title: Diurnal variation in group IIa phospholipase A2 content in tears of contact lens wearers and normal controls.
abstract: OBJECTIVE
  To study the diurnal rhythm in group IIA phospholipase A(2) (GIIAPLA(2)) content of tears and the effect of the wearing time of soft contact lenses (CL) on the content of GIIAPLA(2 )in tears.
  
  
  METHODS
  The GIIAPLA(2 )content of tears was measured by a time-resolved fluoroimmunoassay in 22 healthy controls at 8 a.m., noon, 4 p.m. and 8 p.m. and in 20 CL wearers at 4 p.m. 1-2 days before using CLs and after 4 h (at noon), 8 h (4 p.m.) and 12 h (8 p.m.) use of soft CLs.
  
  
  RESULTS
  The GIIAPLA(2 )content of tears of healthy controls was 80.6+/-47.8 micro g/ml (mean+/-SD). The GIIAPLA(2 )content was lower at 8 a.m. than at noon (p=0.006) and higher at 4 p.m. than at 8 p.m. ( P=0.003). There was no statistically significant difference in the GIIAPLA(2 )content of tears between the CL wearers without CLs (69.47+/-31.2 micro g/ml) and the normal subjects (92.3+/-48.2 micro g/ml) measured at 4 p.m. Compared with healthy controls, the GIIAPLA(2) values in subjects wearing CLs were statistically significantly lower at noon ( P=0.0001) and at 4 p.m. ( P=0.0002).
  
  
  CONCLUSIONS
  In normal subjects, the GIIAPLA(2) content of tears increased from 8 a.m. to noon and decreased from 4 p.m. to 8 p.m. The use of CLs for 4 h and 8 h caused a decrease in the GIIAPLA(2) content of tears. This difference was not seen at 4 p.m. the day when the CL wearers did not use CLs.
authors.affiliation: Department of Ophthalmology, University of Turku, 20520, Turku, Finland.
authors.forename: Valtteri V
authors.initials: VV
authors.lastname: Aho
authors.forename: Ville
authors.initials: V
authors.lastname: Paavilainen
authors.forename: Timo J
authors.initials: TJ
authors.lastname: Nevalainen
authors.forename: Heikki
authors.initials: H
authors.lastname: Peuravuori
authors.forename: K Matti
authors.initials: KM
authors.lastname: Saari
mesh_terms: D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D003263:Contact Lenses, Hydrophilic; D005260:Female; D015200:Fluoroimmunoassay; D054501:Group II Phospholipases A2; D006801:Humans; D008297:Male; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2; D013666:Tears / Q000201:enzymology*
chemical_list: D010741:Phospholipases A; D054501:Group II Phospholipases A2; D054467:Phospholipases A2