Studies on the Pathogenesis of Idiopathic Thrombocytopenic Purpura Part Ⅱ. Studies on Megakaryocytes of the Bone Marrow of Normal Human Beings.

In order to study the function of normal megakaryocytes, experiments were performed by means of the tissue culture of the sternal bone marrow of normal adults. The results are summarized as follows: 1) The author has confirmed the motility, hitherto unknown, of the megakaryocyte, and the observations in detail disclosed it to be one of the important function of this cell. 2) Mature megakaryocytes showed a complicated shape, and the pseudopodia protruded from the margin of the cytoplasm. They seldom sent out tentacle-like filaments, and these exhibited active movement and sometimes separated a platelet from the top. The average of the migration velocity was 3.3 μ/min. 3) The movement of megakaryocytes therefore was classified into 3 types as follows: (1) Movement of deformation (2) Movement of pseudopodia formation (3) Movement of tentacle-like filaments formation 4) The immature megakaryocytes showed only the rotatory movement and no migration. 5) The phagocytosis of carbon particles could not be observed in mature megakaryocytes