|Budget Amount *help
¥2,000,000 (Direct Cost : ¥2,000,000)
Fiscal Year 1991 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1990 : ¥1,200,000 (Direct Cost : ¥1,200,000)
1. Studies on human erythroblasts derived from cord blood
(1) Effect of compression : Proper compression applied to erythroblasts to enhance visualization of their fine structures was proved to affect no influence on their capability to proliferate and differentiate.
(2) Characterization of differentiation Cytoplasmic hemoglobinization was qualitatively surveyed by Soret band micrography. Cell size, movement and enucleation were also proved to be useful indices of differntiation of erythroblasts.
2. Studies on Congenital dyserythropoietic anemia type III (CDA III) erythroblasts The majority of CDA III erythroblasts showed proliferation and differntiation similar to that of normal erythroblasts. Morphogenesis of dysplastic erythroblasts showed the 2 patterns of progression outlined below.
(1) More frequently, morphogenesis began with the appearance of a well demarcated clear area in the nucleus of immature erythroblasts. This clear area reappeared in the daughter cells and granddaughter cel
ls after mitosis. In the latter, the clear area, which increased in frequency, size and rigidity, occupied most of and compartmentalized the nucleus. Terminal differentiation, such as maximal hemoglobinization and vigorous movement, appeared in these cells and the nucleus became lobular. These cells seemed to belong to the end cell generation, because they showed the capacity to grow and attained the cell size at which most CDA III erythroblasts would divide. However, they did not divide. We speculate that this sequence could culminate in the most common type of dysmorphic erythroblasts in CDA III, the large orthochromatic normoblasts with lobular or segmented nucleus with DNA content ranging from 2C to 4C.
(2) Less frequently, abnormalities of mitosis and subsequent cellular behavior, such as tri- or bi-polar mitosis and subsequent fusion of the daughter cells or rapid growth of one daughter cell concomitamt with shrinkage of the other daughter cell were noted. These process preceded cell death. Giant erythroblasts and some binucleate erythroblasts were apparently yielded by this process.