批發(fā)和零售貿(mào)易零售業(yè)-在線瀏覽
2025-02-03 05:39本頁面
【正文】 g enzymes (activated factors). ? AT IIIheparin pathway: major system 80% of the thrombin inhibitory action in plasma. ? Destruction of protein cofactors (., TMPCPS system). ? TMPCPS system degrades cofactors V VIII:C, inhibiting prothrombinase and tenase plexes, respectively. ? Blocking receptor availability needed for plex formation (., Tissue factor pathway inhibitor (TFPI) and annexin V). Proposed Mechanism of AT IIIHeparin System Heparin Thrombin Antithrombin III Lysine sites Serine site Arginine site H Th H AT III AT III Th Proposed Mechanism of Thrombomodulin, Protein C and Protein S (TMPCPS) System Thrombin Prothrombin Protein C Thrombomodulin Thrombin FXa Activated platelet PS FVa x Ca++ Ca++ Activated Protein C Proposed Mechanism of Tissue Factor Pathway Inhibitor (TFPI) Activity FXa Endothelium Tissue factor FVIIa TFPI FXa TFPI TFPI FXa Anticoagulant Factors Fibrinolytic System Method for removing clots and maintenance of a patent vascular system and fibrin deposited during inflammation and tissue injury must be removed. ? Plasmin (serine protease) primarily responsible for fibrinolysis. ? Produced in the liver and kidney, it circulates in an inactive form (plasminogen). ? Activators: tissue plasminogen activator (tPA), cytokinasesurokinases (urine, CSF, tears, saliva, milk, bile, synovial, prostatic and amniotic fluids), erythrocyte erythrokinase, neutropil activator and factor XIIdependent activator (XIIprekallikrienhageman factor cofactor plex). ? In addition to fibrin and fibrinogen, plasmin will hydrolyse a variety of proteins. ? While plasminogen is normally found in blood and body fluids, plasmin is usually absent due to numerous antiplasmins. ? Inactivators: antithrombin III, a2macroglobulin, a1antitrypsin and C1 inactivator. Fibrinolytic System and Factors Regulating Fibrinolysis (Fibrinogenolysis) Plasminogen Activation Inhibition Damaged endothelium Kallikrein Plasminogen activator inhibitor eaminocaproic acid Prekallikrein Streptokinase Urokinase FHIIa tPA Plasmin a2Antiplasmin a2Macroglobulin Complement activation Fibrin/fibrinogen Degradation products Biodegradation of FV, FVIII, FIX, FXI fibrinogen Firbrinogen/fibrin Degradation of Fibrin/Fibrinogen Fibrinogen or Fibrin Fragment X Small Peptides Fragment Y Fragment D Small Peptides Fragment E Fragment D Small Peptides Plasmin Plasmin Plasmin Evaluation of Hemostasis Fundamental physiology and pathophysiology of hemostasis is similar in mammalian species. ? Variables identical for laboratory animals and human patients Platelets ? Platelet count detection of thrombocytopenia ? Clot retraction nonanticoagulated blood ? Failure to separate platelet function defect or thrombocytopenia ? Bleeding time (BT) in vivo test。 low sensitivity ? Used to evaluate platelet function defects ? Thrombocytopenia prolongs BT ? Clotting factor deficiency does not alter BT
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