[Tissue-type plasminogen activator].
Tissue-type plasminogen activator (t-PA) is a serine protease that converts a zymogen plasminogen into an active serine protease, namely, plasmin. Plasmin is the proteolytic enzyme that degrades fibrin. In the absence of fibrin, e.g., in circulating plasma, t-PA activates plasminogen at a very slow rate. However, when fibrin is present, this activity is enhanced two to three orders of magnitude. As a consequence of these kinetic characteristics, plasmin is predominantly generated on the fibrin surface. This in turn results in a relative sparing of circulating fibrinogen and other plasma proteins to plasmin--mediated degradation. Following the demonstration of the potential of natural t-PA as a thrombolytic agent, an intensive effort was launched to enhance its production by recombinant DNA technology. The pharmacological action and the clinical efficacy of t-PA has been tested by several Authors in the treatment of acute myocardial infarction (AMI), and more recently, of pulmonary embolism, a condition for which this drug seems to be very promising: from this point of view this short article provides evidence that the various thrombolytic agents are of equal ability in mediating the rapid lysis of a coronary thrombus after i.v. administration when given appropriately and at the proper time; clinical experience provides little support for the contention of the superiority of t-PA over other thrombolytic agents, particularly for coronary thrombolysis. We are waiting for the results that will come from the GISSI-2 study, that is comparing streptokinase (SK) vs. t-PA in AMI's patients.
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D001157:Arterial Occlusive Diseases / Q000188:drug therapy; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006801:Humans; D009203:Myocardial Infarction / Q000188:drug therapy; D011655:Pulmonary Embolism / Q000188:drug therapy; D013300:Streptokinase / Q000627:therapeutic use; D013924:Thrombophlebitis / Q000188:drug therapy; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*
D005343:Fibrinolytic Agents; D013300:Streptokinase; D010959:Tissue Plasminogen Activator
Attivatore tessutale del plasminogeno.