[Clinical and experimental studies on the formation of calcium bilirubinate gallstones].

We identified the bacteria in the bile and measured the activity of bacterial beta-glucuronidase and analyzed the percentage of bilirubin glucuronide and unconjugated bilirubin by high performance liquid chromatography in the bile of human biliary stone disease. The percentage of positive bacterial infection in the bile are 72.0% with calcium bilirubinate gallstone, and 42.3% with cholesterol gallstone. The activity of beta-Glucuronidase (U/dl.hr.) was significantly higher in the bile of calcium bilirubinate gallstone than that of cholesterol gallstone (7013 +/- 5113 vs 3338 +/- 2615, mean +/- S.D.). Also, the percentage of unconjugated bilirubin (IX alpha) of the bile was significantly higher in calcium bilirubinate gallstone than in cholesterol gallstone (5.7 +/- 4.7% vs 2.6 +/- 2.0%, mean +/- S.D.). The beta-Glucuronidase activity of bacteria was as follows; E. coli 18752, K. pneumoniae 333, E.cloacae 124, S.faecalis 324, and B.fragilis 983. After 60 minutes' incubation at 37 degrees C of normal bile with E.coli, the percentage of unconjugated bilirubin (IX alpha) increased from 1.1% to 9.1%. Whereas, the other four bacteria did not increase the unconjugated bilirubin at all. We confirmed that the increase of unconjugated bilirubin caused by the high bacterial beta-Glucuronidase activity was the most important factor in the formation of calcium bilirubinate gallstone.