Tsukada M

Temperature-dependent formation of vacuolar and canalicular systems in association with degranulation in stimulated neutrophils

Effects of temperature on the morphological changes and degranulation were studied in stimulated neutrophils. Neutrophils were stimulated by formyl‐methionyl‐leucyl‐phenylalanine (FMLP) and cytochalasin B at 4°C, 20°C and 37°C, and they were processed for electron microscopy and biochemical assays of myeloperoxidase (MPO) activity. When neutrophils were stimulated at 4°C, they did not show apparent morphological changes nor release MPO activity. In the cells stimulated at 20°C, there were many cytoplasmic vacuoles, localization of MPO‐positive granules adjacent to the cell membrane and around the vacuoles, MPO‐positive materials in the cavity of the vacuoles, and slightly decreased numbers of granules. They released moderate amounts of MPO activity. The neutrophils at 37° C showed formation of small vacuoles and canaliculi and a marked decrease in the number of MPO‐positive granules indicative of degranulation, and they released increased amounts of MPO activity. There were MPO‐positive materials on the membrane and in the cavity of the vacuoles. Ruthenium red staining showed that the vacuoles were formed open outside the cell. These results indicate that the vacuolar systems are involved in degranulation in stimulated neutrophils and that their formation is dependent on temperature.

Scanning electron microscopic study on red blood cells in several diseases of newborns and infants

Introduction The scanning electron microscope (SEM) has a resolution of 200A which is ten times that of the conventional light microscope, and presents a three-dimensional view of cells. The scanning electron micrograph of blood cells was first reported by Hayes et al. in 1966.1) Since then, several studies have been undertaken on the surface ultrastructure of normal and pathologic blood cells.2-8) Light microscopically, red blood cells are known to show biconcave disk and display morphological alterations under certain circumstances. It is obvious that the scanning electron microscopy enables more accurate morphological analysis of erythrocyte abnormalities than does the light microscopy. Only a few observations under SEM, however, have been carried on the abnormal erythrocytes in a variety of diseases. The present paper reports the scanning electron micrograph of abnormal red blood cells in several disorders of newborns and infants.