title: Further studies of the role of surfactant in premature rupture of the membranes.
abstract: OBJECTIVE
  The purpose of this study was to assess the hypothesis that surface-active phospholipid (i.e., amniotic surfactant) plays a major role in maintaining the mechanical integrity of the chorioamniotic sac.
  
  
  METHODS
  Three studies were designed using chorioamniotic sacs from normal term deliveries. First, it was demonstrated how the extreme hydrophobicity (and lubricity) of amniotic and chorionic epithelium could be greatly reduced by incubating the membrane with bile salts, which react with surface-active phospholipid. Second, hydrophobic probes were used under epifluorescence microscopy to identify any structured surface-active phospholipid. Third, electron microscopy was used to investigate the ultrastructure, by means of a novel fixation procedure that does not destroy hydrophobic interfaces.
  
  
  RESULTS
  Both morphologic studies confirmed planar structures of oligolamellar surface-active phospholipid running parallel to the membrane that contained lamellar bodies.
  
  
  CONCLUSIONS
  These sheets of surface-active phospholipid could be very cohesive within the planes, thus improving tensile strength while promoting shearing between planes to provide the type of lubrication afforded by graphite whose ultrastructure they closely resemble.
authors.affiliation: Department of Physiology, University of New England, Armidale, New South Wales, Australia.
authors.forename: B A
authors.initials: BA
authors.lastname: Hills
mesh_terms: D000650:Amnion / Q000502:physiology* / Q000648:ultrastructure; D000653:Amniotic Fluid / Q000737:chemistry; D001647:Bile Acids and Salts; D002823:Chorion / Q000502:physiology* / Q000648:ultrastructure; D005260:Female; D005322:Premature Rupture of Fetal Membranes / Q000209:etiology*; D006801:Humans; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D011247:Pregnancy; D011663:Pulmonary Surfactants / Q000032:analysis / Q000502:physiology*; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D001647:Bile Acids and Salts; D011663:Pulmonary Surfactants