Laboratory:Determining the concentration of superoxide and catecholamines (adrenaline and noradrenaline) in plasma and urine anion will be determined by ELISA (CatCombi ELISA, IBL, Deventer, The Netherlands), following the manufacturers instructions. Superoxide dismutase activity in plasma will be also assessed using ELISA kits (Cu-Zn superoxid-dismutase ELISA, IBL), and the urinary excretion and plasma levels of lipid peroxides by measuring products react with thiobarbituric acid (TBARS) (OxiSelect TBARS Assay Kit, Cell Biolabs, Inc., San Diego, CA 92126).