title: Protein Z Plasma Levels are Not Elevated in Patients with Non-Arteritic Anterior Ischemic Optic Neuropathy.
abstract: BACKGROUND
  Protein Z is a glycoprotein that acts as a co-factor for the inhibition of activated coagulation factor X. Protein Z circulating in abnormal levels has been associated with increased risk for acute ischemic events. Non-arteritic Anterior Ischemic Optic Neuropathy (N-AION) is caused by acute ischemic infarction of the optic nerve head, supplied by the posterior ciliary arteries.
  
  
  OBJECTIVE
  The aim was to investigate whether there is an association between N-AION and plasma protein Z levels.
  
  
  METHODS
  Twenty-six cases of confirmed N-AION and fifty-two controls were included in the study group. Protein Z was estimated in thawed citrate plasma on both N-AION cases and controls by an enzyme immunoassay. The imprecision of the estimation was satisfactory (CV = 4, 6%).
  
  
  RESULTS
  The controls' protein Z values distributed within a range 340 to 4200 ng/ml (median = 1420, mean = 1673, SD = 1040 ng/ml). Patients' protein Z values distributed within a range 420 to 3600 ng/ml (median = 1030, mean = 1520, SD = 939 ng/ml). There was no statistical difference between the two distributions (Independent t-test, p=0.529).
  
  
  CONCLUSIONS
  In our study, protein Z levels are not implicated in the pathogenesis of non-arteritic anterior ischemic optic neuropathy (N-AION).
authors: University Eye Clinic of Ioannina, Greece.
authors: Ioannis
authors: I
authors: Asproudis
authors: Taxiarchis L
authors: TL
authors: Felekis
authors: Spiridon
authors: S
authors: Gorezis
authors: Lefkothea
authors: L
authors: Dova
authors: Eleni
authors: E
authors: Dokou
authors: Georgios
authors: G
authors: Vartholomatos
authors: Miltiadis
authors: M
authors: Aspiotis
authors: Nikolaos I
authors: NI
authors: Kolaitis