human breast cancer. Clinical applications Urokinase is effective for the restoration of flow to intravenous catheters blocked by clotted blood or fibrin (catheter clearance). Catheters are used extensively to administer treatments to patients for such purposes as dialysis, nutrition, antibiotic treatment and cancer treatment. Approximately 25% of catheters become blocked, meaning that affected patients cannot receive treatment until the catheter has been cleared or replaced. Urokinase is also used clinically as a thrombolytic agent in the treatment of severe or massive deep venous thrombosis, peripheral arterial occlusive disease, pulmonary embolism, acute myocardial infarction (AMI, heart attack), and occluded dialysis cannulas (catheter clearance). It is also administered intrapleurally to improve the drainage of complicated pleural effusions and empyemas. Urokinase is marketed as Kinlytic (formerly Abbokinase) and competes with recombinant tissue plasminogen activator (e.g., alteplase) as a thrombolytic drug. All plasminogen activators (urokinase, tPA) catalyze the production of plasmin, which in turn leads to the breakdown of the fibrin mesh structure in blood clots. While there are commonalities in the mode of action for urokinase and tPA, urokinase has some advantages for treatment of peripheral clots (Pulmonary Embolism, Deep Vein Thrombosis, Peripheral arterial occlusive disease). Unlike tPA, which is activated by binding to the fibrin within clots, urokinase is not sequestered by fibrin and therefore does not specifically attack hemostatic clots. This makes urokinase less likely to break down such hemostatic clots that are essential for ongoing blood vessel repair throughout the body. Dissolution of these “good” clots can lead to serious adverse events through hemorrhagic bleeding. Years of clinical study have confirmed the safety advantage of using urokinase. Consequently, urokinase has been preferentially used in deep venous thrombosis and peripheral arterial occlusive disease where it is administered directly to the site of the clot while tPA is preferred in AMI where peripheral bleeding is a secondary consideration. A revolutionary method for the production of urokinase was patented by Evelyn Nicol in 1976 (U.S. Patent No. 3,930,944). Nicol was believed to be the first African American woman to receive a molecular biology patent. Society and culture The presence of a fibrinolytic enzyme in human urine was reported in 1947, without a name given for such an enzyme behind its effect. In 1952 a purified form of the enzyme was extracted from human urine and named "urokinase" for "urinary kinase". The full text for this article is lost, and the only citation points