AN IMPROVED TECHNIQUE FOR THE ASSAY OF RED-BLOOD-CELL SUPEROXIDE-DISMUTASE (SOD) ACTIVITY

Superoxide dismutase (SOD) activity of erythrocytes from normal pregna nt women (controls) and from pre-eclamptic toxaemia (PET) cases was de termined by the method of Winterbourn et al. (J Lab Clin Med 1975;85:3 37-341) with slight modifications. Instead of the Michaelis-Menten typ e of plot that is usually obtained and which these authors have found to be imprecise, a linear plot was obtained when the reciprocal values for the percentage inhibition of nitroblue tetrazolium (NET) reductio n were plotted against the corresponding volumes of red blood cell (RB C) extract. This plot was found to give precise values for the volumes of RBC extracts required for 50% inhibition of NET reduction. Consequ ently, a clearer understanding is beginning to emerge regarding the SO D activity of PET cases compared with that of normal pregnant women.