Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.6 (thromboplastin)
 13,278 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The established antithrombotic agents are effective but they have limitations which have provided opportunities for the development of new antithrombotic compounds. Of these new agents, the antithrombin III-independent thrombin inhibitors and the platelet GPIIb/IIIa receptor antagonists are the most advanced in their development. Other new antithrombotic agents include the antithrombin III-independent factor Xa inhibitors, activated protein C, soluble thrombomodulin and tissue factor pathway inhibitor. Of the GPIIb/IIIa antagonists, the humanized 7E3 antibody and integrin have been evaluated in phase III studies. The 7E3 antibody was effective in preventing both short-term and longer-term complications of coronary angioplasty. The antithrombin III-independent thrombin inhibitors hirudin and hirulog have also been evaluated in phase III studies. The studies with hirudin as an adjuvant to coronary thrombolysis had to be terminated and restarted at lower dosages because of an unacceptable incidence at intracranial hemorrhage and the study with hirulog produced equivocal results.
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PMID:New antithrombotics for the treatment of acute and chronic arterial ischemia. 954 19

We report a complication observed in a 77-year-old man admitted to another hospital for "de novo" angina, in which coronary angiography showed a proximal 65% stenosis of the left anterior descending artery. The patient was medically stabilized, but one month later he developed unstable angina that was not controlled by heparin, nitrate and calcium antagonist infusions. Therefore, he was started on ReoPro (0.25 mg/kg bolus and 10 micrograms/min infusion) but because of persisting symptoms, he was transferred to our unit for urgent PTCA. Angioplasty plus stenting was successful and angina disappeared. The ReoPro infusion was stopped (6 hours after it had been started) for mild oral bleeding. Blood analysis was normal (including platelet count) except for the activated partial thromboplastin (PTT) and prothrombin (PT) time, which exceeded the laboratory limits of determination. Consequently, heparin infusion was also stopped. Eight hours after PTCA, he suddenly developed hypotension, bradycardia and loss of consciousness. The echocardiogram revealed a large pericardial effusion with diastolic collapse of the right cardiac chambers. The patient was treated with volume expanders, plasma and platelet units in an attempt to reestablish a normal hemodynamic pattern and normal platelet function. Elective pericardiocentesis was performed 24 hour later, with drainage of 800 ml of hematic effusion. Severe hemorrhagic complication was induced by ReoPro despite a normal platelet count. This was successfully counteracted with plasma and platelet infusion.
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PMID:[Cardiac tamponade after coronary angioplasty induced by treatment with ReoPro]. 1032 29

In addition to inhibiting platelet (plt) aggregation abciximab, a glycoprotein (GP) IIb/IIIa antagonist, reduces coagulation in blood or platelet-rich plasma. We assessed the effects of abciximab (10 micro g mL(-1)) on adhesion-dependent procoagulant activity (PCA) of plt upon: (i) collagen to model initial adhesion; or (ii) plasma clot or fibrin to model a preformed thrombus with retained thrombin activity. In a two-stage assay gel-filtered plt (GFP) first adhered on collagen, plasma clot, or fibrin, and plt activation was traced with platelet factor 4 (PF 4) release. Second, PCA was measured on adherent plt (i) by soluble prothrombin fragments (F1 + 2); and (ii) chromogenically by adding defibrinated plasma and thromboplastin. Abciximab inhibited aggregation upon collagen-adherent plt both in the absence and presence of plasma. In contrast, without plasma abciximab enhanced plt deposition to fibrin surfaces depending on thrombin generation and fibrin polymerization. However, abciximab reduced PCA and generation of F1 + 2 on adherent plt surface-independently by 35%, whereas PF 4 release persisted. Also, a GP Ib inhibitor, mAb SZ2, attenuated PCA by 40% alone, and by 65% together with abciximab, leaving 35% of PCA unaltered. Abciximab decreased generation of new thrombin on both collagen- and clot-adherent plt. However, abciximab did not inhibit alpha-granule release, suggesting distinct pathways for PCA and release reaction. Deposition of isolated plt on clots in the presence of abciximab was dependent on thrombin and polymerizing plt-derived fibrin(ogen). Due to local consumption of natural anticoagulants adjacent to a preformed thrombus the antithrombotic effect of abciximab benefits from additional inhibition of thrombin.
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PMID:Abciximab inhibits procoagulant activity but not the release reaction upon collagen- or clot-adherent platelets. 1287 19

Thromboembolic disorders are one of the disorders for which we are still on the look out for a safe and efficient drug. Despite the widespread use of antithrombotic drugs for the prevention and treatment of arterial and venous thrombosis, thromboembolic diseases continue to be a major cause of death and disability worldwide. This shows our inefficiency in searching efficacious and safe antithrombotic drugs. We have reached the basic mechanism of thrombus formation and by interrupting various steps of this mechanism, we can prevent as well as treat thromboembolic disorders. In continuation of Aspirin, now, we are using Clopidogrel, Ticlopidine and GpIIb/IIIa inhibitors (Abciximab, Tirofiban and Eptifibatide). Warfarin is an old antithrombotic drug which is still being used; but due to various side effects and drug interactions, we are bound to use newer drugs. Newer antiplatelet drugs include Prasugrel, Ticagrelor and Cangrelor, whereas newer thrombin inhibitors are Ximelgatran and Dabigatran. Apixaban is also a newer entry in this category as factor Xa inhibitor. Idrabiotaparinux is an indirect inhibitor of Xa as it accelerates the activity of antithrombin. Moreover, researches and trials for better and safe drugs are ongoing.
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PMID:Newer antithrombotic drugs. 2157 50