Angina, Unstable/drug therapy; Coronary Thrombosis/prevention & control; Disease Models, Animal; Drugs, Investigational/therapeutic use; Fibrinolytic Agents/therapeutic use; Oligopeptides/therapeutic use; Platelet Glycoprotein GPIIb-IIIa Complex/antagonists & inhibitors; Angina, Unstable/physiopathology; Animals; Anticoagulants/administration & dosage; Anticoagulants/adverse effects; Anticoagulants/pharmacology; Anticoagulants/therapeutic use; Blood Coagulation/drug effects; Coronary Thrombosis/etiology; Dogs; Dose-Response Relationship, Drug; Drugs, Investigational/administration & dosage; Drugs, Investigational/adverse effects; Drugs, Investigational/pharmacology; Female; Femoral Artery; Fibrinolytic Agents/administration & dosage; Fibrinolytic Agents/adverse effects; Fibrinolytic Agents/pharmacology; Hemodynamics/drug effects; Humans; Infusions, Intravenous; Male; Oligopeptides/administration & dosage; Oligopeptides/adverse effects; Oligopeptides/pharmacology; Platelet Aggregation/drug effects; Platelet Aggregation Inhibitors/administration & dosage; Platelet Aggregation Inhibitors/adverse effects; Platelet Aggregation Inhibitors/pharmacology; Platelet Aggregation Inhibitors/therapeutic use; Rabbits; Thrombosis/etiology; Thrombosis/prevention & control