title: The measurement of the lactonase activity of paraoxonase-1 in the clinical evaluation of patients with chronic liver impairment.
abstract: OBJECTIVE
  We investigated the analytical performance of a new assay of the lactonase activity of paraoxonase-1 and its efficacy in the assessment of liver damage.
  
  
  METHODS
  Serum lactonase activity was determined by the hydrolysis of 5-thiobutyl butyrolactone in 633 healthy individuals and 369 patients with chronic liver disease. Paraoxonase-1, 2, and 3 gene polymorphisms were analyzed by the MassArray method.
  
  
  RESULTS
  Linearity was up to 10 U/L. Detection limit was 0.12 U/L. Imprecision was < or = 17.7%. Lactonase values in our normal population were 5.99 (3.29-13.61) U/L. Lactonase activity showed a lower influence of genetic polymorphisms than the classical assay using paraoxon. Both measurements showed a similar efficiency in testing for liver dysfunction.
  
  
  CONCLUSIONS
  We report a reliable assay using a non-toxic substrate for the measurement of serum lactonase activity. The influence of genetic variability is low. The assay could be a useful addition to tests evaluating liver impairment.
authors.affiliation: Centre de Recerca Biomèdica, Hospital Universitari de Sant Joan, Institut d'Investigacions Sanitàries Pere Virgili, Universitat Rovira i Virgili, Reus, Spain.
authors.forename: Judit
authors.initials: J
authors.lastname: Marsillach
authors.forename: Gerard
authors.initials: G
authors.lastname: Aragonès
authors.forename: Raul
authors.initials: R
authors.lastname: Beltrán
authors.forename: Joan
authors.initials: J
authors.lastname: Caballeria
authors.forename: Juan
authors.initials: J
authors.lastname: Pedro-Botet
authors.forename: Carlos
authors.initials: C
authors.lastname: Morcillo-Suárez
authors.forename: Arcadi
authors.initials: A
authors.lastname: Navarro
authors.forename: Jorge
authors.initials: J
authors.lastname: Joven
authors.forename: Jordi
authors.initials: J
authors.lastname: Camps
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D043303:Aryldialkylphosphatase / Q000235:genetics / Q000378:metabolism*; D002908:Chronic Disease; D004950:Esterases / Q000235:genetics / Q000378:metabolism; D005260:Female; D005838:Genotype; D006801:Humans; D008075:Lipoproteins, HDL / Q000378:metabolism; D008077:Lipoproteins, LDL / Q000378:metabolism; D008107:Liver Diseases / Q000201:enzymology*; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D004950:Esterases; D043303:Aryldialkylphosphatase; C468411:PON2 protein, human; C113656:PON3 protein, human