Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.7 (plasmin)
 9,023 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Six monoclonal antibodies raised against human fibrinogen have been characterized. Mouse monoclonal antibodies were targeted against sequential epitopes on the immunodominant D-domain of fibrinogen and they crossreacted with all molecules containing the D-domain [fibrin, fibrin(ogen)-degradation products]. Their behavior was not influenced by proteolytic degradation of fibrinogen with plasmin. Rat MoAbs were specific for the conformational epitopes on intact fibrinogen. Their reactivities were substantially lower with fibrin(ogen)-degradation products. Degradation of structures on intact fibrinogen was concomitant with the decay of rat MoAbs reactivity. Those structures were presumably on the C-terminal end of fibrinogen alpha chain and/or on the N-terminal end of fibrinogen beta chain.
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PMID:Comparison of several mouse and rat monoclonal antibodies against human fibrinogen. 898 53

We report on a patient with coagulation abnormalities induced by a wasp sting anaphylaxis. First, we observed an unclottable activated partial thromboplastin time and a significant anti-Xa activity (equivalent to a therapeutic heparin range), whereas the patient had received no heparin. This phenomenon is probably due to activated mast cells that release mediators such as heparin and tryptase. Heparin can then act as an anticoagulant by binding to antithrombin. This "heparinization" explains the anti-Xa activity contributing to the unclottable activated partial thromboplastin time detected in our patient. Second, we noted an extremely low fibrinogen level in the presence of normal platelet count and only a slight increase of D-dimers (absence of important disseminated intravascular coagulation). This is probably due to serum tryptase released during massive mast cell activation. Tryptase cleaves the alpha and beta chains of fibrinogen. This results in the removal of the thrombin cleavage site and of the critical polymerization site from the fibrinogen beta chain. Thrombin- initiated clot formation is therefore inhibited. Tryptase also acts directly on the fibrinolytic pathway by activating the single-chain urinary-type plasminogen activator, resulting in conversion of plasminogen into plasmin and therefore degradation of fibrinogen and other coagulation factors. This hyperfibrinogenolysis explains both the prolonged clotting times and the low fibrinogen level observed. Although our patient did not bleed, in other settings (trauma, during surgery) patients with anaphylaxis may present bleeding disorders. Although the mechanisms underlying these abnormalities have been described in vitro and in vivo animal trials, this is the first time they are described in a human clinical setting.
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PMID:"Heparinization" and hyperfibrinogenolysis by wasp sting. 2207 26