Thrombolysis with tissue plasminogen activator in acute myocardial infarction: no additional benefit from immediate percutaneous coronary angioplasty

A randomised trial of 367 patients with acute myocardial infarction was performed to determine whether an invasive strategy combining thrombolysis with recombinant tissue-type plasminogen activator (rTPA), heparin, and acetylsalicylic acid, and immediate percutaneous transluminal coronary angioplasty (PTCA) would be superior to a noninvasive strategy with the same medical treatment but without immediate angiography and PTCA. Intravenous infusion of 100 mg rTPA was started within 5 h after onset of symptoms (median 156 min). Angiography was performed 6-165 min later in 180 out of 183 patients allocated to the invasive strategy; 184 patients were allocated to the non-invasive strategy. Immediate PTCA reduced the percentage stenosis of the infarc

EFFECTS OF COLD-ROLLING AND POST-DEFORMATION ANNEALING ON THE MARTENSITIC TRANSFORMATION OF A TiNi SHAPE MEMORY ALLOY

The thermoelastic transformation of shape-memory titanium -nickel alloys is highly influenced by the microstructural state of the alloy and particularly by the plastic deformation of the metal. In this study, the influence of cold-work and annealing on martensitic and austenitic transformations is performed with "in situ" thermoelectric power measurements during thermal cycling. In the recrystallized state the transformations are very well defined, and the thermal hysteresis is generally less than 30 degrees. After work hardening the transformation becomes "diffuse" and is no longer observed if the deformation is greater than a critical value of approximately 25%. The effects of post-deformation heat treatments were also characterized using a heavily cold- worked metal within a temperature range of 300-600°C. Thermoelectric power measurements applied to the characterization of shape-memory alloy transformation proves to be a high performance tool displaying a great sensitivity to martensitic transformation