The complementary role of scanning electron microscopy in renal pathological diagnosis.

Techniques applied in SEM studies of a solid organ such as the kidney are reviewed. The tissue can be prepared by razor sectioning, ethanol cryofracture and ultraplanning of polyethylene glycol embedded tissue. Tissues embedded in paraffin can also be used. Glomeruli and tubuli can be isolated from renal biopsies. A new procedure for tubular isolation is based on sequential digestion by trypsin, pepsin and Pronase E. SEM examination has proved useful in a number of renal diseases, such as glomerular diseases, hypertensive renal disease, an tubular diseases, including medullary cystic disease, adult polycystic disease, and acute tubular necrosis. Particularly in human acute tubular necrosis, SEM was helpful. SEM has also contributed to the study of the physiologically important basal-lateral surfaces of human, dog, rat, rabbit and frog renal tubules, and in particular allowed the elucidation of patterns of processes on the basal-lateral surfaces of proximal S1, S2, and S3 tubular segments, thin limbs, distal ascending and convoluted limbs and collecting ducts in human tubules.