title: Sedimentation of biliary sludge: effect on composition of gallbladder bile from patients with cholesterol, mixed, or pigment stones.
abstract: BACKGROUND
  Ultracentrifugation of bile has been used extensively to remove insoluble material such as sludge from bile before further studies of cholesterol nucleation. Although it has been recognized that this procedure may affect the composition of gallbladder bile, it has not been studied systematically in different gallstone populations. Therefore, we investigated the concentration of biliary lipids, protein, mucin, and bilirubin before and after ultracentrifugation.
  
  
  METHODS
  Gallbladder bile samples were aspirated during laparoscopic surgery from 66 patients (35 with cholesterol, 16 with mixed, and 15 with pigment stones).
  
  
  RESULTS
  Whereas the concentrations of bile acids, phospholipids, protein, and bilirubin in gallbladder bile did not change significantly after ultracentrifugation, cholesterol (20.6 +/- 1.6 to 14.8 +/- 1.2 mmol/l) and mucin concentrations (0.99 +/- 0.2 to 0.67 +/- 0.1 mg/ml) and the cholesterol saturation index (1.68 +/- 0.12 to 1.31 +/- 0.10) decreased significantly in gallbladder bile from patients with cholesterol stones.
  
  
  CONCLUSIONS
  Sedimentation of biliary sludge may profoundly affect the composition of gallbladder bile, which has to be considered in studies of cholesterol saturation and nucleation. The cholesterol concentration difference between native and ultracentrifuged bile reflects the insoluble crystalline fraction of cholesterol and may be useful for quantitation of the mass of cholesterol crystals in gallstone-associated bile samples.
authors.affiliation: Depts. of Medicine II, Ludwig-Maximilians University Munich, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Jungst
authors.forename: R
authors.initials: R
authors.lastname: Del Pozo
authors.forename: S
authors.initials: S
authors.lastname: Christoph
authors.forename: J F
authors.initials: JF
authors.lastname: Miquel
authors.forename: M I
authors.initials: MI
authors.lastname: Eder
authors.forename: V
authors.initials: V
authors.lastname: Lange
authors.forename: E
authors.initials: E
authors.lastname: Frimberger
authors.forename: C
authors.initials: C
authors.lastname: Von Ritter
authors.forename: G
authors.initials: G
authors.lastname: Paumgartner
mesh_terms: D001646:Bile / Q000737:chemistry*; D001647:Bile Acids and Salts / Q000032:analysis; D001654:Bile Pigments / Q000032:analysis; D001663:Bilirubin / Q000032:analysis; D002769:Cholelithiasis / Q000737:chemistry*; D002784:Cholesterol / Q000032:analysis; D005260:Female; D006801:Humans; D008297:Male; D009077:Mucins / Q000032:analysis; D010743:Phospholipids / Q000032:analysis; D011506:Proteins / Q000032:analysis; D014461:Ultracentrifugation
chemical_list: D001647:Bile Acids and Salts; D001654:Bile Pigments; D009077:Mucins; D010743:Phospholipids; D011506:Proteins; D002784:Cholesterol; D001663:Bilirubin