title: Improved facial nerve identification with novel fluorescently labeled probe.
abstract: OBJECTIVE
  By phage display, we have developed a novel peptide (NP41) that binds selectively to nerves following systemic administration. We evaluated the pattern of facial nerve labeling with fluorescently-labeled NP41 (F-NP41). We also tested whether F-NP41 highlights facial nerves well enough to identify nerve stumps accurately several weeks after nerve transection.
  
  
  METHODS
  Forty-seven wild-type mice were studied prospectively. One surgeon performed the nerve transection, reanastomosis, and monitoring of functional recovery.
  
  
  METHODS
  Fluorescent labeling: F-NP41 was administered intravenously (20 mice). Nerve labeling was studied with fluorescence microscopy. Transection and reanastomosis: the right facial nerve was transected (25 mice). Three weeks after transection, F-NP41 was administered intravenously and fluorescence microscopy was used to identify the nerve stumps and reanastomosis in one group. Nerve identification and reanastomosis was performed with white light in another group without F-NP41. The control group underwent sham surgery. Time to nerve identification was recorded. Functional recovery was monitored for at least 8 weeks.
  
  
  RESULTS
  We found excellent labeling of intact and transected facial nerves following F-NP41 administration. Several weeks following nerve transection, F-NP41 provided accurate identification of the proximal and distal nerve stumps. Following reanastomosis, time to recovery and level of functional recovery was similar in the absence and presence of F-NP41.
  
  
  CONCLUSIONS
  We show improved visualization of facial nerves with a novel systemically applied fluorescently labeled probe. Use of F-NP41 resulted in accurate identification of facial nerve stumps several weeks following transection. Functional recovery was similar with and without the use of F-NP41.
authors.affiliation: Division of Otolaryngology-Head and Neck Surgery, University of California-San Diego, San Diego, California 92093-0647, USA.
authors.forename: Amy P
authors.initials: AP
authors.lastname: Wu
authors.forename: Michael A
authors.initials: MA
authors.lastname: Whitney
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Crisp
authors.forename: Beth
authors.initials: B
authors.lastname: Friedman
authors.forename: Roger Y
authors.initials: RY
authors.lastname: Tsien
authors.forename: Quyen T
authors.initials: QT
authors.lastname: Nguyen
mesh_terms: D000714:Anastomosis, Surgical; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D005154:Facial Nerve / Q000473:pathology* / Q000601:surgery; D020220:Facial Nerve Injuries / Q000473:pathology* / Q000601:surgery; D005452:Fluoresceins; D005456:Fluorescent Dyes; D008164:Luminescent Proteins / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D009410:Nerve Degeneration / Q000473:pathology; D009416:Nerve Regeneration / Q000502:physiology; D019151:Peptide Library; D010455:Peptides; D018800:Thy-1 Antigens / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; C558459:F-NP41 peptide; D005452:Fluoresceins; D005456:Fluorescent Dyes; D008164:Luminescent Proteins; D019151:Peptide Library; D010455:Peptides; D018800:Thy-1 Antigens; C054562:yellow fluorescent protein, Bacteria