One protein that I've been researching into for the past few decades is plasminogen activator inhibitor-1 (PAI-1), which plays a key part in the fibrinolytic (clot breakdown) system. As a doctoral student I helped to make the first discoveries on the links between PAI-1 and CAD, and since then the protein has become a recurrent theme in my research. For example, I was the first scientist in the world to show that high concentrations of PAI-1 in the blood increase the risk of cardiac infarction.