LIPIDS AND MEMBRANES IN THE ORGANIC MATRIX OF URINARY CALCIFIC CRYSTALS AND STONES

The ultrastructure of the organic matrix of de-mineralized urinary sto nes was examined by standard transmission and scanning electron micros copy as well as after malachite green-glutaraldehyde fixation. Crystal ghosts of both calcium oxalate and calcium phosphate were made of amo rphous material and were dispersed in a matrix containing amorphous, f ibrillar, and membranous substances. Malachite green positive material was seen to be associated with the ghosts, as well as with the membra nous and fibrillar components of the organic matrix. Calcium oxalate a nd calcium-phosphate crystals, induced in human urine in vitro were al so found to be associated with an organic matrix containing lipids and proteins. It is suggested that the intimate association between cryst als and lipids is a result of the involvement of cellular membranes in the nucleation of these crystals.