title: The effect of diet on total antioxidant status, erythrocyte membrane Na+,K+-ATPase and Mg2+-ATPase activities in patients with classical galactosaemia.
abstract: OBJECTIVE
  Classical galactosaemia is characterized by high levels of galactose-1-phosphate (Gal-1-P), galactose and galactitol. In vitro studies have shown modulation of the rat brain Na+,K+-ATPase and Mg2+-ATPase activities by Gal-1-P. The aim of this study was to evaluate the erythrocyte membrane Na+,K+-ATPase and Mg2+-ATPase activities in galactosaemic patients and to correlate them to Gal-1-P, total antioxidant status (TAS) and membrane protein content (PC).
  
  
  METHODS
  Nine patients (N=9) originally on "loose diet" (group B) were requested to follow their diet strictly (group A). Twelve healthy children were the controls (group C). The activities of the enzymes, TAS and Gal-1-P in blood were determined spectrophotometrically. In the in vitro study, erythrocyte membranes from controls were preincubated with Gal-1-P (300 microM), and then with l-cysteine (0.83 mM) or reduced glutathione (0.83 mM) whereas these from the patients with the antioxidants only.
  
  
  RESULTS
  Na+,K+-ATPase, Mg2+-ATPase, TAS and PC were significantly (P<0.001) reduced (0.31+/-0.03, 1.7+/-0.2 micromol Pi/hxmg protein, 0.89+/-0.02 mmol/l, 36.8+/-2.0 g/l, respectively) in group B as compared with those of group A (0.58+/-0.06, 2.5+/-0.2 micromol Pi/hxmg protein, 1.41+/-0.11 mmol/l, 51.5+/-3.1g/l, respectively) and controls (0.67+/-0.05, 3.2+/-0.2 micromol Pi/hxmg protein, 1.65+/-0.12 mmol/l, 64.0+/-3.5 g/l, respectively). Gal-1-P levels in group B was significantly higher than those in group A and controls. Positive correlation coefficients were found between the enzyme activities, PC and TAS whereas Gal-1-P inversely correlated to the enzyme activities. Incubation of the erythrocyte membranes from the patients with the antioxidants failed to restore the activities of inhibited enzymes, whereas the inhibition by Gal-1-P in controls was reversed.
  
  
  CONCLUSIONS
  High blood Gal-1-P concentrations resulted in low TAS and PC. The inhibition of Na+,K+-ATPase and Mg2+-ATPase may be due to the presence of free radicals and/or the elevated Gal-1-P.
authors.affiliation: Institute of Child Health, "Aghia Sophia" Children's Hospital, GR-11527 Athens, Greece.
authors.forename: Kleopatra H
authors.initials: KH
authors.lastname: Schulpis
authors.forename: Helen
authors.initials: H
authors.lastname: Michelakakis
authors.forename: Theodore
authors.initials: T
authors.lastname: Tsakiris
authors.forename: Stylianos
authors.initials: S
authors.lastname: Tsakiris
mesh_terms: D000975:Antioxidants / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D017301:Ca(2+) Mg(2+)-ATPase / Q000187:drug effects / Q000378:metabolism*; D002648:Child; D004032:Diet; D004910:Erythrocyte Membrane / Q000201:enzymology*; D005260:Female; D005693:Galactosemias / Q000178:diet therapy* / Q000378:metabolism; D005695:Galactosephosphates / Q000097:blood; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D000254:Sodium-Potassium-Exchanging ATPase / Q000187:drug effects / Q000378:metabolism*; D013053:Spectrophotometry / Q000379:methods
chemical_list: D000975:Antioxidants; D005695:Galactosephosphates; C029973:galactose-1-phosphate; D017301:Ca(2+) Mg(2+)-ATPase; D000254:Sodium-Potassium-Exchanging ATPase