Studies on levels and interactions of contact activation factors in plasma. A basis for the elucidation of their function in anaphylactoid reactions to dextran and to radiographic contrast media

摘要

Summary of findings and conclusions of relevance: A part of the thesis concerns the effects of intravenous contrast media on the blood pressure and on factors of the contact activation system in the rat. The intravenous injection of dextran induced a profound and lasting fall in blood pressure, preceded by significant lowering in prekallikrein and activation factor 12. The non-ionic radiographic contrast media iohexol caused no significant alterations, neither in blood pressure, nor in levels of contact factors, whereas the ionic radiographic contrast media iodipamide had effects. It induced a rapid, but short-lived, fall in blood pressure and a small, but statistically significant reduction in the measurable amount of activation factor 12a. An observation of significance was that pretreatment of the rats with iodipamide almost blocked the dextran-induced blood pressure fall, and abolished the reduction in prekallikrein and activation factor 12a. It is concluded that the ionic radiographic contrast media used was capable of blocking dextran shock in the rat by preventing an activation of contact activation system. 130 refs., 5 figs. (Atomindex citation 24:041673)