THE FINE STRUCTURE OF GLOMERULAR EPITHELIAL CELLS IN EXPERIMENTAL RENAL AMYLOIDOSIS

The fine structure of the three types of glomerular cells, especially glomerular epithelial cells was studied In experimental renal amyloidosis induced by both prolonged sensitization of focus antigens and casein. The presence of cytoplasmic invaginations which contained a bundle of amyloid fibrils in almost parallel array and intracytoplasmlc membrane‐surrounded amyloid fibrils were observed in the glomerular epithelial cells. They are quite comparable to those which were demonstrated in reticuloendothelial cells In other reports. The intracytoplasmlc invaginations opened at the plasma membrane either in the urinary space or in the basement membrane. By processing serial sections on the minimal deposition of amyloid, some of the Intracytoplasmlc membrane‐surrounded amyloid fibrils were found to be connected with parallel arrayed extracellular amyloid fibrils. Amyloid accumulated usually In large amount In mesangial matrix and along the basement membrane adjacent to the mesangium, but isolated depositions of amyloid, minimal though definite, were sometimes observed in the subepithelial and subendothelial areas, and in the epithelial cells far from the mesangium.