USE OF HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY IN DEFINING THE ABNORMALITIES IN THE FREE AMINO-ACID PATTERNS IN THE CEREBROSPINAL-FLUID OF PATIENTS WITH ASEPTIC-MENINGITIS

Free amino acids were quantitatively determined in cerebrospinal fluid (CSF) and plasma samples from patients with aseptic meningitis by a newly developed high performance liquid chromatographic (HPLC) method. The method of analysis was based on precolumn derivatization of orthophthalaldehyde in the presence of 2-mercaptoethanol and detection was made at E(ex) = 340 nm and E(em) = 450 nm. The method was sensitive and the limit for detection was < 1 pmol for most of the amino acids. It took 45 min to separate 26 amino acids with highly reproducible results, giving a coefficient of variance for retention times and integrated areas < 0.4% and 2%, respectively, after five replicate runs. The results accumulated in 10 patients were compared statistically with 11 age-matched healthy controls. Among the amino acids almost all the neurotransmitter candidates, such as aspartic acid, glutamic acid, glutamine, glycine, tyrosine, phenylalanine and gamma-aminobutyric acid (GABA), were significantly increased in the patients' CSF, whereas arginine and threonine were low. No change was observed in plasma amino acids in patients as compared to healthy controls. The higher levels of most of the neurotransmitters, especially GABA, aspartic acid and glutamic acid, could be used diagnostically in assessing the progression and remission in aseptic meningitis.