MICROSTRUCTURE OF GALLSTONES

Abstract

Electron microprobe analysis, X-ray diffraction, and IR spectroscopy were used to investigate the nature and arrangement of materials present in human gallstones. Ca phosphate and carbonate deposits present centrally in many stones were mixed with a pigmented phase containing Cu and protein. In several stones, the central Ca deposits were surrounded by discrete adjacent layers of Ca bilirubinate and cholesterol. The Ca bilirubinate layer was distinguished from other pigmented layers by its higher protein content and increased Fe/Cu ratio. This sequence of Ca salt and cholesterol deposition occurred in the outer layers of some stones. The phase relationships are consistent with a biphasic mechanism of stone growth in which Ca salts and lipid were alternately deposited. Ca salt precipitation was inferred to initiate the sequence, as Ca salts were found at the stone centers. The layer sequence was discussed in terms of some possible effects of damage to the gallbladder wall caused by the Ca salt deposits.