Composition of bile pigment in gallstones and bile and their etiological significance.

Abstract

Abstract In order to gain further information on the etiology of bile pigment-calcium stones, gallstone samples from 37 patients were visually classified as cholesterol stones (19 subjects), bile pigment-calcium stones (10 subjects), and pure-pigment stones (eight subjects). Bile from each gallstone case was analyzed with ethyl anthranilate and p -iodoaniline diazo reagent. The mean concentration of bilirubin in gallbladder bile from each gallstone case was significantly lower than that of the controls, regardless of their type. Unconjugated and monoconjugated bilirubin was significantly increased in all stone types, particularly with bile pigment-calcium stones, and the difference between each group was significant except between cholesterol and pure-pigment stones. A significant decrease of glucuronide (δ-azopigment) was noted in the bile pigment-calcium stone and pure-pigment stone cases; the latter also had a considerable increase in isomeric glucuronides (β- and γ-azopigment). Bacteriological study suggested a close relationship between the increase in unconjugated bilirubin and the over-all infection rates of the bile. Gallstone analysis revealed that the proportion of conjugated bilirubin was significantly lower in the bile pigment-calcium stones than in cholesterol and pure-pigment stones. These findings all agree with the general belief that during the formation of bile pigment-calcium stone, bacterially mediated hydrolysis of bilirubin conjugates occurs, leading to the formation of monoconjugate and further to unconjugated bilirubin, which in turn precipitates as calcium bilirubinate, thus resulting in stone formation.