James J. Hagan

Comparative chemical structure and pharmacokinetics of MRI contrast agents.

Tweedle MF, Eaton SM, Eckelman WC, Gaughan GT, Hagan JJ, Wedeking PW, Yost FJ. Comparative chemical structure and pharmacokinetics of MRI contrast agents. Invest Radiol 1988; 23(Suppl 1):S236‐S239. The blood clearance kinetics of five gadolinium complexes, Gd(L), were determined in rats and the results interpreted in terms of an open two‐compartment pharmacokinetic model. The complexes were tested in vitro for stability in serum and in aqueous solutions of ions that they might encounter in vivo and that might be expected to react with the Gd(L) complexes to produce uncomplexed gadolinium. Reaction with serum was observed in two instances. Chemical structural differences among the chelating ligands appear to govern the overall reactivity of their Gd(L) complexes. It may be inferred from the results that a preferred structural feature of the ligand is the presence of a 12‐membered 1,4,7,10‐tetraaza macrocycle.

A predictive test for adverse reactions to contrast media. Preliminary results.

Eaton SM, Hagan JJ, Tsay HM, Tweedle MF, Nickoloff EL, Loberg MD, Yost FJ. A predictive test for adverse reactions to contrast media: preliminary results. Invest Radiol 1988;23(Suppl 1):S206‐S208. In a prospective study, whole blood samples drawn from patients prior to their being injected with contrast media were incubated with zymosan to activate the complement cascade. The samples were tested for various analytes, including C3a, thromboxane B2 (TxB2), beta thromboglobulin and platelet factor 4 (PF4). Of 207 patients receiving contrast media, only eight experienced reactions, which were mild. Levels of the platelet constituents were generally elevated in these patients. Specificity and sensitivity were 89% and 83%, respectively, for the combined TxB2 and PF4 radioimmunoassay data. Using the Wilcoxon‐Mann‐Whitney rank sum test, both PF4 and TxB2 were collected with RCM reactions at the R < .05 level. Although preliminary, the results suggest that RCM reactions are predictable by the in vitro test procedures described.