Arterial Occlusive Diseases/prevention & control; Fibrinolytic Agents/pharmacology; Hirudins/analogs & derivatives; Thrombosis/prevention & control; Venous Thrombosis/prevention & control; Amino Acid Sequence; Animals; Arginine/analogs & derivatives; Arterial Occlusive Diseases/chemically induced; Arterial Occlusive Diseases/drug therapy; Arteriovenous Shunt, Surgical; Chlorides; Drug Evaluation, Preclinical; Ferric Compounds/toxicity; Fibrinolytic Agents/therapeutic use; Fibrinolytic Agents/toxicity; Glass; Hemorrhage/chemically induced; Heparin/pharmacology; Heparin/therapeutic use; Heparin/toxicity; Hirudin Therapy; Hirudins/chemistry; Hirudins/pharmacology; Hirudins/toxicity; Molecular Sequence Data; Pipecolic Acids/pharmacology; Pipecolic Acids/therapeutic use; Pipecolic Acids/toxicity; Platelet Aggregation/drug effects; Platelet Aggregation Inhibitors/pharmacology; Platelet Aggregation Inhibitors/therapeutic use; Platelet Aggregation Inhibitors/toxicity; Rats; Recombinant Proteins/chemistry; Recombinant Proteins/pharmacology; Recombinant Proteins/therapeutic use; Recombinant Proteins/toxicity; Sequence Alignment; Sequence Homology, Amino Acid; Serine Proteinase Inhibitors/pharmacology; Serine Proteinase Inhibitors/therapeutic use; Serine Proteinase Inhibitors/toxicity; Sulfonamides; Thrombin/antagonists & inhibitors; Thrombin/pharmacology; Thrombosis/chemically induced; Thrombosis/drug therapy; Vena Cava, Inferior; Venous Thrombosis/drug therapy