title: Measurement of the expiratory ammonia concentration and its clinical significance.
abstract: Although gaseous ammonia (NH3) can freely enter cells through the plasma membrane where NH3 is cyto(neuro)toxic, NH3 and ionic ammonia (NH4+) contents have not been studied in biological materials. We developed a new method for measurement of expiratory NH3 concentration, which may reflect blood NH3 concentrations. The method is a sensor tube type-gas assay system. Expiratory NH3 concentration in patients with chronic liver diseases increased when their blood ammonia (NH4(+)+NH3) concentrations increased above 90 micrograms/dl (normal range; 12-66 micrograms/dl). However, cirrhotic patients, who had relatively higher expiratory NH3 concentration compared to blood NH3 concentrations (calculated from Henderson-Hasselbalch formula), were found to have subclinical encephalopathy. Measurement of expiratory NH3 concentration may be of clinical significance for the diagnosis of encephalopathy associated with hyperammonemia.
authors.affiliation: Third Department of Internal Medicine, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Wakabayashi
authors.forename: Y
authors.initials: Y
authors.lastname: Kuwabara
authors.forename: H
authors.initials: H
authors.lastname: Murata
authors.forename: K
authors.initials: K
authors.lastname: Kobashi
authors.forename: A
authors.initials: A
authors.lastname: Watanabe
mesh_terms: D000641:Ammonia / Q000097:blood / Q000378:metabolism*; D001944:Breath Tests; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008103:Liver Cirrhosis / Q000378:metabolism; D008297:Male; D008875:Middle Aged
chemical_list: D000641:Ammonia