title: Diffusion of substances into human cholesterol gallstones.
abstract: OBJECTIVE
  The possibility that substances penetrate gallstones and accumulate after stones have formed has not been examined. The specific aims of this study were to determine whether cholesterol gallstones are permeable and, if so, the effect of molecular weight on permeability.
  
  
  METHODS
  Cholesterol gallstones from patients with multiple stones were collected during surgery and incubated in fluorescein solution or in solutions of fluoresceinated albumin or immunoglobulin (Ig) G. To determine egress from the stones, some stones were removed from the fluoresceinated solution after incubation and placed in bicarbonate buffer. The total area of the stone and the area of dye that had diffused into the calculi were calculated. To determine mass of penetrating IgG, stones were powdered after incubation, and IgG was measured by an enzyme-linked immunosorbent assay.
  
  
  RESULTS
  All substances penetrated stones. Although all compounds tested diffused back out of the stones when they were replaced in buffer, proteins did so more slowly than fluorescein.
  
  
  CONCLUSIONS
  Substances of different molecular weights can diffuse into and out of cholesterol gallstones. These findings must be taken into account when considering the role of substances contained in stones on stone formation and growth.
authors.affiliation: Department of Surgery, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, University of Toronto, Canada.
authors.forename: J R
authors.initials: JR
authors.lastname: Sanabria
authors.forename: G A
authors.initials: GA
authors.lastname: Upadhya
authors.forename: R P
authors.initials: RP
authors.lastname: Harvey
authors.forename: S M
authors.initials: SM
authors.lastname: Strasberg
mesh_terms: D002769:Cholelithiasis / Q000378:metabolism*; D002784:Cholesterol / Q000378:metabolism*; D004058:Diffusion; D019793:Fluorescein; D005452:Fluoresceins / Q000737:chemistry / Q000493:pharmacokinetics; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry / Q000378:metabolism; D008970:Molecular Weight; D010539:Permeability; D012710:Serum Albumin, Bovine / Q000493:pharmacokinetics
chemical_list: D005452:Fluoresceins; D007074:Immunoglobulin G; D012710:Serum Albumin, Bovine; D002784:Cholesterol; D019793:Fluorescein