title: Allantoin as a marker of oxidative stress in human erythrocytes.
abstract: BACKGROUND
  Uric acid is the final product of purine metabolism in humans. It was determined that this compound has important antioxidative properties and it may be oxidized to allantoin by various reactive oxygen species. Therefore, the measurement of allantoin may be useful for the determination of oxidative stress in humans.
  
  
  METHODS
  We measured allantoin and uric acid in human plasma and erythrocytes obtained from patients with chronic renal failure before hemodialysis (n=30) and blood donors (n=30). We used a method based on selective isolation of allantoin from deproteinized plasma and erythrocyte lysate samples on AG 1-X8 resin and its derivatization to glyoxylate-2, 4-dinitrophenylhydrazone. Separation of glyoxylate-2, 4-dinitrophenylhydrazone from interfering substances was achieved on reversed phase HPLC with gradient elution and UV/VIS detection at 360 nm. Uric acid was determined by reversed phase HPLC with UV/VIS detection at 292 nm.
  
  
  RESULTS
  We found significant differences in allantoin and uric acid concentration between the patients with chronic renal failure and the control group both in plasma (20.5+/-6.5 micromol/L and 323.9+/-62.9 micromol/L vs. 2.1+/-1.1 micromol/L and 270.1+/-62.3 micromol/L, p<0.05) and erythrocytes [82.8+/-39.1 nmol/g hemoglobin (Hb) and 110.7+/-28.8 nmol/g Hb vs. 20.1+/-6.1 nmol/g Hb and 82.1+/-23.7 nmol/g Hb, p<0.05].
  
  
  CONCLUSIONS
  Significant higher levels of allantoin in both plasma and erythrocytes of patients with chronic renal failure indicate that allantoin may be used as a good marker of oxidative stress.
authors.affiliation: Department of Biological and Biochemical Sciences, Faculty of Chemical Technology, University of Pardubice, Pardubice, Czech Republic. roman.kandar@upce.cz
authors.forename: Roman
authors.initials: R
authors.lastname: Kand'ár
authors.forename: Pavla
authors.initials: P
authors.lastname: Záková
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000481:Allantoin / Q000097:blood*; D000975:Antioxidants / Q000378:metabolism; D015415:Biomarkers / Q000097:blood*; D002851:Chromatography, High Pressure Liquid; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D014527:Uric Acid / Q000097:blood
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D014527:Uric Acid; D000481:Allantoin