Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0034065 (pulmonary embolism)
 14,979 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hageman factor, a coagulation factor (Factor 12) is reported to be deficient in users of OCs (oral contraceptives) in this letter to the editor. A 21-year-old female on OCs for 4 months was admitted with sudden onset of chest pain and shortness of breath; a lung scan confirmed bilateral pulmonary embolism. She underwent a coagulation screen, prior to heparin therapy, which revealed a partial thromboplastin time of 120 seconds. A 15% Hageman factor deficiency was found. It is suggested that before prescribing OCs, physicians should screen patients by partial thromboplastin time, at the least, to determine if Hageman factor is deficient.
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PMID:Hageman factor deficiency and oral contraceptives. 610 95

Coagulation factor XII (FXII, Hageman factor, EC = 3.4.21.38) is the zymogen of the serine protease, factor XIIa (FXIIa). FXII is converted to FXIIa through autoactivation induced by "contact" to charged surfaces. FXIIa is of crucial importance for fibrin formation in vitro, but deficiency in the protease is not associated with excessive bleeding. For decades, FXII was considered to have no function for coagulation in vivo. Our laboratory developed the first murine knockout model of FXII. Consistent with their human counterparts, FXII(-/-) mice have a normal hemostatic capacity. However, thrombus formation in FXII(-/-) mice is largely defective, and the animals are protected from experimental cerebral ischemia and pulmonary embolism. This murine model has created new interest in FXII because it raises the possibility for safe anticoagulation, which targets thrombosis without influence on hemostasis. We recently have identified platelet polyphosphate (an inorganic polymer) and mast cell heparin as in vivo FXII activators with implications on the initiation of thrombosis and edema during hypersensitivity reactions. Independent of its protease activity, FXII exerts mitogenic activity with implications for angiogenesis. The goal of this review is to summarize the in vivo functions of FXII, with special focus to its functions in thrombosis and vascular biology.
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PMID:In vivo roles of factor XII. 2299 91