title: [Sialic acid in normal human tears].
abstract: OBJECTIVE
  We measured the concentration of sialic acid, the terminal component of mucin, in normal human tears.
  
  
  METHODS
  Tear samples were collected from 31 healthy volunteers(50.7 years old on average) using micropipett after instillation of saline. We investigated the correlation of concentration between glycoprotein and sialic acid, the difference between these in the right eye and left eye, and the reproducibility of the sampling procedure.
  
  
  RESULTS
  There was significant correlation of concentration between glycoprotein and sialic acid(right eye: r = 0.989, p < 0.0001; left eye: r = 0.988, p < 0.0001). There was no significant difference between these in the right and left eye. Also, the reproducibility was considered acceptable in three measurements of sialic acid with the present procedure. The concentration of sialic acid in normal diluted tears was 37.1 micrograms/ml on average.
  
  
  CONCLUSIONS
  Our data indicates that concentration of sialic acid reflects that of glycoprotein and this method of measurement is applicable to the analysis of disorders with mucin deficiency.
authors.affiliation: Department of Ophthalmology, Kyoto Prefectural University of Medicine, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Nakamura
authors.forename: N
authors.initials: N
authors.lastname: Yokoi
authors.forename: H
authors.initials: H
authors.lastname: Tokushige
authors.forename: S
authors.initials: S
authors.lastname: Kinoshita
mesh_terms: D005260:Female; D006023:Glycoproteins / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D019158:N-Acetylneuraminic Acid / Q000032:analysis*; D015203:Reproducibility of Results; D013666:Tears / Q000737:chemistry*
chemical_list: D006023:Glycoproteins; D019158:N-Acetylneuraminic Acid