Morphometric Studies of Megakaryocytes in Human and Rat Fetal, Infantile and Adult Hematopoiesis. I. Observations on human fetuses and blood dyscrasias

As a basic study of the thrombocytic productivity of megakaryocytes. Author have investigated the megakaryocyte size from fetal stage to the adult stages.
In the present study, a comparative review was made on the megakaryocyte size in blood dyscrasias (AML, ALL and ITP). In comparison with the mean megakaryocyte size of adult used as control, the mean size in AML and ALL was smaller, but the mean size in ITP was larger than the control.
The megakaryocyte size during fetal hematopoietic stage was remarkably smaller than that in acute leukemia.
Further data were added to author findings reported previously on the megakaryocyte size during the fetal, neonatal, infantile and adult stages of man, but these additional data did not bring about hardly any change to the results of author previous report.
1) There was no significant difference between fetal hepatic megakaryocytes and fetal marrow megakaryocytes of the same age.
2) The mean megakaryocyte size during the fetal hematopietic stage increased with lapse of time.
3) The mean megakaryocyte size after birth increased from the fetal stage for at least to one year after birth when they became almost equivalent in size to those of adults.