Abstract
The surface structure of reticulocytes was examined by scanning electron microscopy (SEM) which does not seem to have been clearly described hitherto.
Based on the results of preliminary experiments the following methods were employed. Erythrocytes were stained with 0.5% new methylene blue (NMB) in 0.15M phosphate buffer. NMB stain by BRECHER generally used for reticulocyte counting was found to remarkably affect the external structure of erythrocytes. Stained erythrocytes were fixed in 1% glutaraldehyde, washed with water and dried on a middle piece cut out from a Thoma's or a Buerker-Tuerk's hemocytometer. The reticulocytes confirmed by light microscopy were identified under SEM by referring their positions on the central sectioned area and photographed. The external structures of 57 reticulocytes from 10 healthy adults were identical to mature erythrocytes with smooth surface, i.e., the majority were concave discs, some were discs and a few were swollen concave discs.
About half of 123 reticulocytes from 4 cases of reticulocytosis had a similar contour but often had some pits on the surface probably indicating BESSIS' “rhopheocytosis.” The remainding were spheroid or spherical with hollows, elevations and pits. The hollows and elevations were frequently accumulated at a pole of the cells, suggesting the previous denucleation though that portion. A possible transformation from a latest erythroblast to a mature erythrocyte was presented. Reticulocytes in reticulocytosis appeared to differ morphologically between different conditions or diseases.
