Exam 1 Review:  Chapter 17:  Fibrinolysis and Anticoagulation

fibrinolysis - The breakdown of the fibrin in a clot, usually by the proteolytic (enzymatic) action of plasmin; a normal ongoing process that dissolves fibrin and results in the removal of small blood clots; drugs causing fibrinolysis are used therapeutically.

plasminogen - The inactive precursor protein to plasmin which is found in body fluids and blood plasma and is incorporated in large quantities into forming clots.

plasmin = fibrinolysin - The a trypsin-like proteolytic enzyme which is formed from the plasminogen by the action of tissue plasminogen activator (t-PA) in blood plasma and dissolves the fibrin in blood clots; it also acts on activated clotting factor XII and on complement to activate the complement cascade.

thrombolytic agents - Any drugs which can break up clots, used therapeutically when a clot is blocking the flow of blood to a vital organ, e.g., the heart or brain, or to debride a wound or burn; commonly used drugs include tissue plasminogen activator (t-PA), APSAC (anisoylated plasminogen streptokinase activator complex), streptokinase, and urokinase.

tissue plasminogen activator (t-PA) - (1) A clot-dissolving (fibrinolytic) enzyme which is produced naturally by the endothelial cells in the walls of blood vessels and which catalyzes the conversion of plasminogen to plasmin;  (2) A preparation of this enzyme that is produced by genetic engineering and used to dissolve clots blocking coronary arteries in acute myocardial infarction = heart attack and cranial arteries in certain cases of stroke.

anticoagulant - (1) Any agent or drug which prevents or retards the clotting of blood in vivo, e.g., endogenous heparin, which must be administered IV, and oral drugs* including warfarin (trade name Coumadin), coumarins, dicumarol,  which interfere with Vitamin K synthesis of certain clotting factors [*nickname - "blood thinners," a very poor choice of words!]  (2) Any agent or drug which prevents the clotting of blood in vitro; used in the preparation of anticoagulated laboratory blood specimens or donor blood for transfusion; e.g., heparin and a variety of calcium-chelating agents including EDTA, citrate, oxalate, and flouride.

heparin - An endogenous anticoagulant; an acidic sulfur-containing mucopolysaccharide found in basophils and tissue mast cells, especially in lung and liver tissue, which has the ability to prevent the clotting of blood by inhibiting the activity of thrombin; intravenous heparin sodium is used in the treatment of thrombosis.

warfarin - A white crystalline compound, C₁₉H₁₆O₄, used as a rodenticide and as an anticoagulant because of its ability to inhibit thrombin activation; (trade name Coumadin).

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