title: Prolidase activity and its diagnostic performance in bipolar disorder.
abstract: OBJECTIVE
  Proline has an important role in the brain. Prolidase, a proline splitting enzyme, which is also involved in oxidative stress is not investigated in bipolar disorder (BD).
  
  
  METHODS
  66 BD type I patients and 66 healthy controls were enrolled. Serum prolidase activity was measured in both groups via venous sampling. We have compared patients and controls as well as 3 subgroups of patients (24 euthymic, 22 manic, and 20 depressive patients).
  
  
  RESULTS
  Prolidase activity was significantly higher in patients (p<0.001, t=14.517). There wasn't any significant difference among euthymic, manic and depressives (p=0.305, f=1.211). Positive predictive value was 98.5% and negative predictive value was 92.4% above the cutoff point 502.9375U/L of prolidase activity.
  
  
  CONCLUSIONS
  Prolidase activity is impaired in BD, which may be associated with oxidative stress. Prolidase activity may be a trait marker for diagnosing bipolar disorder.
authors.affiliation: Psychiatry Department, Medical School, Harran University, S.Urfa, Turkey. drselek@yahoo.com
authors.forename: Salih
authors.initials: S
authors.lastname: Selek
authors.forename: Abdurrahman
authors.initials: A
authors.lastname: Altindag
authors.forename: Gulben
authors.initials: G
authors.lastname: Saracoglu
authors.forename: Hakim
authors.initials: H
authors.lastname: Celik
authors.forename: Nurten
authors.initials: N
authors.lastname: Aksoy
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D001714:Bipolar Disorder / Q000097:blood / Q000175:diagnosis / Q000201:enzymology*; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D003866:Depressive Disorder / Q000097:blood / Q000201:enzymology; D004150:Dipeptidases / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D012372:ROC Curve
chemical_list: D015415:Biomarkers; D004150:Dipeptidases; C022449:proline dipeptidase