title: Radioiodinated plasminogen: an imaging agent for pre-existing thrombi.
abstract: We have reinvestigated radioiodinated plasminogen as an agent for localizing preformed thrombi. Canine plasminogen was isolated from fresh plasma by the affinity chromatography technique on a lysine-sepharose 4B column and tagged with I-123 or I-131, at less than one iodine atom per molecule of enzyme, by the conventional ICI method. When injected into dogs more than 2 days after thrombus induction, radioiodinated plasminogen produced thrombus-to-blood activity ratios of 7.8 +/- 2.4. Thrombi as old as 6 days can be visualized in 80% of the cases. Both the weight of the thrombus and the thrombus-to-blood ratio are more variable for 1-day-old thrombi; this may be associated with plasminogen release accompanying thrombus retraction. The results suggest that radioiodinated plasminogen has potential as an imaging agent for pre-existing thrombi.
mesh_terms: D000818:Animals; D004285:Dogs; D007457:Iodine Radioisotopes; D010958:Plasminogen; D011877:Radionuclide Imaging; D013924:Thrombophlebitis / Q000175:diagnosis*
chemical_list: D007457:Iodine Radioisotopes; D010958:Plasminogen