title: Serum platelet-activating factor acetylhydrolase (PAF-AH) activity in more than 3000 healthy Japanese.
abstract: BACKGROUND
  A spectrophotometric assay for platelet-activating factor acetylhydrolase (PAF-AH) activity differs from the radioisotopic assay in its value because of a difference in substrate specificity. The spectrophotometric assay is more precise than the radioisotopic assay, providing information that is not clear with the radioisotopic assay.
  
  
  METHODS
  We measured the serum PAF-AH activity in 3106 healthy Japanese, utilizing the spectrophotometric assay with an Hitachi 7170 automatic analyzer. We also measured the serum PAF-AH activity in 18 healthy volunteers to investigate the effect of diet and the change in activity in a day and over 6 weeks. Changes were examined at 0 (day 1), 1, 2, 4 and 6 weeks.
  
  
  RESULTS
  The mean value for females was significantly lower than that of males at the 5% level and both male and female activity had a tendency to increase with advancing age. It is known that the PAF-AH is primarily associated with LDL in blood and the PAF-AH activity correlated with the total cholesterol (r=0.52, n=126) and the LDL cholesterol (r=0.60, n=126) concentrations. In the diet study, there was no observable effect on activity. No difference in PAF-AH activity was observed between serum and plasma sample types. The serum PAF-AH activity was stable at 7 degrees C for at least 7 days and at -20 degrees C for at least 2 months.
  
  
  CONCLUSIONS
  The serum PAF-AH activity in women was lower than in men until the menopausal age was reached. We could use not only fresh fasting serum, but also plasma sample, non-fasting sample and stored sample to estimate the PAF-AH activity.
authors.affiliation: Diagnostic Research and Development Department, R&D Division, Nesco Company, Azwell Inc., 2-24-3 Sho, Osaka 567-0806, Ibaraki, Japan. te-kosaka@azwell.co.jp
authors.forename: T
authors.initials: T
authors.lastname: Kosaka
authors.forename: M
authors.initials: M
authors.lastname: Yamaguchi
authors.forename: K
authors.initials: K
authors.lastname: Miyanaga
authors.forename: K
authors.initials: K
authors.lastname: Mizuno
mesh_terms: D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase; D000328:Adult; D000367:Age Factors; D002784:Cholesterol / Q000097:blood; D002940:Circadian Rhythm; D004032:Diet; D004435:Eating; D005260:Female; D006801:Humans; D008297:Male; D008593:Menopause; D008875:Middle Aged; D010741:Phospholipases A / Q000097:blood*; D012016:Reference Values; D012737:Sex Factors; D013053:Spectrophotometry / Q000379:methods; D014280:Triglycerides / Q000097:blood
chemical_list: D014280:Triglycerides; D002784:Cholesterol; D010741:Phospholipases A; D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase