title: Radiation-induced increased platelet-activating factor activity in mixed saliva.
abstract: BACKGROUND
  Platelet-activating factor (PAF), a family of structurally-related phospholipid mediators of inflammation, is present in normal human mixed saliva; however, its role in oral biology and the homeostasis of oral host defense mechanisms remains to be established.
  
  
  METHODS
  The current study was designed to evaluate the salivary levels of PAF in patients with oral mucositis that developed as a complication of head and neck irradiation for oral cancer. PAF activity was assessed in platelet bioassay and expressed relative to the activity of authentic PAF, 1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphocholine (C16:0-AGEPC).
  
  
  RESULTS
  A significant increase in salivary PAF levels was observed in patients with mucositis (47,032 +/- 12,731 C16:0-AGEPC fmole equivalents/ml of saliva, mean +/- SE, N = 7) as compared with normal subjects (5,568 +/- 1,135 C16:0-AGEPC fmole equivalents/ml of saliva, N = 27). Phospholipid fractionation of the PAF isolated from the saliva of patients with mucositis by reverse phase high performance liquid chromatography revealed a single peak of activity that corresponded with the elution profile of C16:0-AGEPC, the most biologically active molecular species of PAF. In contrast, the PAF isolated from normal human mixed saliva contained multiple molecular species of PAF.
  
  
  CONCLUSIONS
  These results suggest that this potent phospholipid inflammatory mediator may play a role in the inflammation and tissue injury associated with mucositis resulting from radiation treatment for oral cancer.
authors.affiliation: Department of Pathology, University of Texas Health Science Center San Antonio.
authors.forename: L M
authors.initials: LM
authors.lastname: McManus
authors.forename: K K
authors.initials: KK
authors.lastname: Ostrom
authors.forename: C
authors.initials: C
authors.lastname: Lear
authors.forename: E B
authors.initials: EB
authors.lastname: Luce
authors.forename: D L
authors.initials: DL
authors.lastname: Gander
authors.forename: R N
authors.initials: RN
authors.lastname: Pinckard
authors.forename: S W
authors.initials: SW
authors.lastname: Redding
mesh_terms: D006801:Humans; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000378:metabolism / Q000473:pathology; D009062:Mouth Neoplasms / Q000532:radiotherapy*; D010972:Platelet Activating Factor / Q000378:metabolism*; D011832:Radiation Injuries; D012016:Reference Values; D012463:Saliva / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects*; D013280:Stomatitis / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D014081:Tooth Extraction
chemical_list: D010972:Platelet Activating Factor