THE APPLICATION OF PEDRI TO THE STUDY OF FREE-RADICALS IN-VIVO

Proton-electron double-resonance imaging (PEDRI) has considerable valu e for study of the distribution and elimination pathways of nitroxide foe radicals (NFRs). This has been illustrated by its use in studies o f kidney function in the living rat in which the NFR proxyl carboxylic acid (PCA) has been employed as a 'tracer'. The technique, at its pre sent stage of development, can demonstrate location of PCA in enough d etail to observe the passage through kidney cortex and medulla differe ntially, and to see the NFR within the major abdominal blood vessels. These studies are helping towards an understanding of the metabolic fa te of PCA, as well as providing information about kidney performance a fter challenge with a nephrotoxin. In addition, nitric oxide complexes , formed in vivo by providing rats with a nitrite-rich diet, have been observed ex vivo using PEDRI and field-cycled DNP.