Evaluation of the effects of Gd complexes used as magnetic resonance imaging contrast agents, on superoxide dismutase: Comparison of two methods

Investigations are currently being made into the safety of gadolinium compl ex contrast agents used in Magnetic Resonance Imaging. Their hyperosmolalit y or potential Gd3+ release is evoked as a cause of various anaphylactoid r eactions to be observed in humans after intravenous injection. An estimatio n has already been made of their effects on the liberation of reactive oxyg en intermediates by neutrophils. The purpose of this study was to find a su itable method to measure SOD activity in the presence of these hyperosmolar solutions, and to evaluate their action on this activity. Two techniques w ere compared to measure this activity. Results and statistical analysis sho wed that pyrogallol autoxidation was greatly affected by solution osmolalit ies, whereas ferricytochrome C reduction was not. Gadopentetate dimeglumine and gadoterate meglumine seemed to activate Cu, Zn SOD in vitro, but did n ot exhibit any SOD-like activity. Gadodiamide did not interfere with this s ystem of detoxication.