On metal elements in pure pigment gallstones

T total of 17 metal elements (Ag, Al, B, Bi, Ca, Cu, Fe, K, Mg, Mn, Mo, Na, P, Pb, Si, Sn and Zn) were identified by spectroanalysis of various gallstone specimens. In the pure pigment stone which is characterized by black appearance, the metal elements were more various in sort and the spectra of respective elements were more intense than in the calcium bilirubinate stone and the cholesterol stone. As compared with other gallstones, the pure pigment stone contained Ca, Cu, Fe, Mg and Mn at higher concentrations, as determined by semiquantitative analysis, and on incineration yielded more ash. Concentrations of Ca and Mg seemed to parallel the ash content of gallstone, while Cu and Fe did not show such a tendency and were relatively specific to the pure pigment stone irrespective of ash content. These results indicate that metal elements, particularly Cu and Fe, play a role in the formation of black substances of the pure pigment stone, possibly as complex compounds with bilirubin derivatives.