The detection of effaced podocytes by high resolution light microscopy.

Fifteen cases of renal minimal change disease and five normal glomeruli were studied by high resolution light microscopy (HRLM) and transmission electron microscopy (TEM). Effacement of podocytes usually is accompanied by aggregation of microfilaments in the cytoplasm of the epithelial cells parallel to the glomerular basement membrane (GBM). The aggregated microfilaments were detected as a dense blue line by high resolution light microscopy. The presence of this line appears to be a reliable sign for the detection of diffusely effaced podocytes by light microscopy. However, when effacement of podocytes was not accompanied by the condensation of microfilaments, the detection of this change by HRLM was more difficult.