Cell coat of podocytes in patients with nephrotic syndrome.

Renal biopsies from 23 patients with the nephrotic syndrome and five patients with slight or no proteinuria were examined for the presence of cell coat of podocytes by light and electron microscopy. Of those with nephrotic syndrome, five had minimal change disease, nine focal glomerular sclerosis, six membraneous nephropathy and three amyloidosis. Colloidal iron and phosphotungstic acid stains were used for the demonstration of anionic and neutral polysaccharide components of the cell coat. On light microscopy, the colloidal iron reaction showed a reduction in intensity of the stain in glomeruli of patients with massive proteinuria, as compared to those with slight or no proteinuria. On electron microscopy, only the cell coat lining the surface of the foot processes disappeared parallel to the loss of these structures, while the coat covering the surface facing the urinary space remained unchanged with both stains.