Gallstones--mineralogical and chemical investigations.

A comparative study of the mineralogical-structural characteristics and chemical composition of gallstones was performed on stone samples removed intraoperatively from the gallbladders of 12 patients. The study included all the types of gallstones. Their chemical components determined were: bilirubin, cholesterol, phospholipids, calcium, proteins. The stones were examined physically (size, number, shape, color) and the radial or concentric disposition of the layers was estimated on cross-sections. Thin sections (2 X 10(-2)mm) were obtained and examined by polarizing microscope in order to observe the inner structural characteristics. The crystallographic analysis of all the types of stones studied is reported. In all the samples, a perfect concordance was found between the mineralogical structure and the chemical composition of the gallstones. The results obtained are valuable premises for further research in the formation of stones, since a mineralogical study offers the possibility to estimate variations of crystal aggregation, according to the local changes of the gallbladder (inflammation, bacterial growth, pH, etc.).