title: Spectroscopic and mechanical evaluation of thin film commonly used for banding congenital portosystemic shunts in dogs.
abstract: OBJECTIVE
  To (1) determine whether different types of thin film used to occlude congenital portosystemic shunts are cellophane, and (2) evaluate the influence of saline immersion and sterilization on the tensile properties of cellophane.
  
  
  METHODS
  Ex vivo spectroscopic evaluation and mechanical testing.
  
  
  METHODS
  Rectangular strips of thin film from 4 sources.
  
  
  METHODS
  Samples were evaluated with Fourier Transform Infrared Spectroscopy and microscopy with a polarizing lens. Samples consistent with cellophane were divided into 5 sterilization groups: non-sterile, autoclave, gamma irradiation, hydrogen peroxide and ethylene oxide. Samples were tested while dry or after saline solution immersion. Tensile properties were compared using ANOVA, unpaired t-tests, Mann-Whitney U-tests and Fisher's exact tests. P < 0.05 was considered significant.
  
  
  RESULTS
  One thin film was consistent with cellophane and it could be differentiated from the other thin films by visible striations. Cellophane was strongest when strips were oriented parallel with its fiber direction and saline immersion reduced its strength by 48% (P < .001). All sterilization methods except autoclave significantly weakened wet cellophane (ethylene oxide [P < .001], gamma irradiation [P < .001], and hydrogen peroxide [P < .001]).
  
  
  CONCLUSIONS
  Thin film from most sources was not consistent with cellophane. Autoclave sterilization is the best way to preserve the strength of wet cellophane.
authors.affiliation: Department of Surgical and Radiological Sciences, University of California-Davis, Davis, CA 95616, USA.
authors.forename: Rebecca R
authors.initials: RR
authors.lastname: Smith
authors.forename: Geraldine B
authors.initials: GB
authors.lastname: Hunt
authors.forename: Tanya C
authors.initials: TC
authors.lastname: Garcia-Nolen
authors.forename: Samuel
authors.initials: S
authors.lastname: Stump
authors.forename: Susan M
authors.initials: SM
authors.lastname: Stover
mesh_terms: D000818:Animals; D002476:Cellophane / Q000737:chemistry*; D004283:Dog Diseases / Q000601:surgery*; D004285:Dogs; D019563:Mechanics; D009996:Osmotic Fragility; D011168:Portal System / Q000473:pathology*; D017550:Spectroscopy, Fourier Transform Infrared; D013242:Sterilization; D013499:Surface Properties; D013718:Tensile Strength; D054079:Vascular Malformations / Q000601:surgery / Q000662:veterinary*
chemical_list: D002476:Cellophane