Study on sideroblasts as a determi­nation method of the erythropoietic function of bone marrow

With the purpose to study sideroblasts as a means of diagnosing blood diseases and to pursue the metabolism of non-hemin iron in erythroblasts we investigated sideroblasts (erythroblasts containing iron granules stainable by Prussian blue) under various erythropoietic conditions in the human and rabbits, and obtained the following results: 1. In blood diseases the proportion of sideroblasts in the case of low erythropoietic condition is higher and in the case with accelerated erythropoietic condition and of iron deficiency it tends to be lower than that in normal persons. Further, obtaining sideroblastogram and sideroblast ratio (S. r.) from the classification of Types I, Ⅱ, and Ⅲ according to the iron granule content, it has been proven that abnormal conditions can be clearly distinguished from the normal, indicating that sideroblasts are closely associated with erythropoietic function. This is proven to be a far superior method for the diagnosis as well as for the prognosis of blood diseases than the determination of serum iron. 2. In experimental anemic rabbits the relationship of sideroblasts to the condition of erythropoietic function is still more clearly recognized, and it has been found that variations in the sideroblast count is dependent upon the condition of the equilibrium between the iron supply from serum iron and the iron utilization controlled by the erythropoietic function. 3. In addition, in the iron-treated rabbits under various erythropoietic conditions we have been able to confirm that there are a certain mechanism and a limitation to the iron intake by erythroblasts, and that erythroblasts take essentially three steps of metabolic processes, namely, intake, retention, and utilization of iron almost simultaneously, in the latter half of the maturation stage.