Sialic acids in human gastric aspirates: detection of 9-O-lactyl- and 9-O-acetyl-N-acetylneuraminic acids and a decrease in total sialic acid concentration with age

Clin Sci (Lond). 1993 May;84(5):573-9. doi: 10.1042/cs0840573.


1. The total sialic acid content of human gastric aspirates was measured using a colorimetric assay. Care was taken to optimize the assay and to eliminate interference. 2. The sialic acid content of gastric aspirates collected under resting conditions from 77 patients with non-ulcer dyspepsia was found to decrease with age from > 100 micrograms/ml at 25 years and younger to < 20 micrograms/ml above 70 years of age. 3. Analysis of the sialic acids by gas chromatography, mass spectrometry and thin-layer chromatography showed the presence of N-acetylneuraminic acid and two O-acylated derivatives, 9-O-acetyl- and 9-O-lactyl-N-acetylneuraminic acids. These forms were predominantly glycosidically bound. 4. Thin-layer chromatographic analysis of individual aspirate samples showed that the O-acetylated sialic acids were present in all samples, with a maximum of 25% and a minimum of 5% of the total sialic acids.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Aging / metabolism*
  • Chromatography, Thin Layer
  • Female
  • Gas Chromatography-Mass Spectrometry
  • Gastric Juice / chemistry
  • Gastric Juice / metabolism*
  • Humans
  • Male
  • Middle Aged
  • Sialic Acids / analysis
  • Sialic Acids / metabolism*


  • Sialic Acids
  • 9-O-acetyl-N-acetylneuraminic acid
  • N-acetyl-9-O-lactylneuraminic acid