Striated membranous structures in renal glomerular tufts. An electron microscopy study of 340 human renal biopsies.

Striated membranous structures are membranes 200 plus or minus 20 A thick. They are very common in both normal and pathologic human glomeruli, since they were found in 221 of 340 renal biopsies studied. Their appearance varies according to the plane of the section: on cross-section they resemble a pile of plates or double longitudinal bands. On tangential section they have an areolar appearance. Striated membranous structures are located in the basement membrane, mesangial matrix, or extracellular pathologic deposits such as amyloid or "immune" deposits. These membranes, probably double layered, are of unknown origin. They might derive from the focal or total lysis of cellular elements included within basement membrane-like material or extracellular deposits.