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

A black man with a prolonged partial thromboplastin time has a severe deficiency of plasma thromboplastin antecedent (PTA) (factor XI) measured both in clotting assays and immunoassays, suggesting a diagnosis of homozygous PTA deficiency. His offspring seemed to be heterozygous carriers of PTA deficiency. Additionally, the proband and two of his children had decreased Hageman factor (factor XII) levels consistent with those of heterozygous carriers of Hageman trait. To our knowledge, this is the first case known of PTA deficiency in a black person. Its pattern of inheritance was independent of that of factor VII deficiency.
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PMID:Plasma thromboplastin antecedent (Factor XI) deficiency in a black family. 723 15

Normal newborn infants have a prolonged partial thromboplastin time compared to that of older infants or adults. This finding has been related to combined deficiencies of multiple clotting factors, with the exception of proaccelerin (factor V) and antihemophilic factor (factor VIII). The present study confirms the presence of decreased titers of Hageman factor (HF, factor XII), plasma prekallikrein, and high molecular weight kininogen during the neonatal period, as demonstrated in clotting assays; the degree of these relative deficiencies is usually such that only the low titer of HF appears to contribute significantly to the abnormally long PTT. Additionally, procoagulant titers of HF and plasma prekallikrein were relatively lower than the concentration of these factors determined immunologically. The mechanisms underlying this phenomenon are not known.
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PMID:Studies on some coagulation factors (Hageman factor, plasma prekallikrein, and high molecular weight kininogen) in the normal newborn. 743 82

Fifty-six strains of lactobacilli were examined for the production of glycosidases and proteases (arylamidases) that could be associated with the ability to grow in vivo and/or be a factor in the pathogenesis of endocarditis. The strains were from seven species, with an emphasis on Lactobacillus rhamnosus and Lact. paracasei subsp. paracasei, both of which have been associated with endocarditis and provided 12 of the 13 strains isolated from cases of the disease. Other species were Lact. acidophilus, Lact. plantarum, Lact. salivarius, Lact. fermentum and Lact. oris. Commonly expressed glycosidase activities were alpha-D-galactosidase and beta-N-acetyl-D-glucosaminidase followed by beta-D-glucosidase and alpha-L-fucosidase. The combined production of beta-N-acetyl-D-glucosaminidase and alpha-D-galactosidase was a feature of the endocarditis isolates. In contrast, beta-D-galactosidase was produced by very few of the strains within species implicated in endocarditis but most of the strains of Lact. salivarius, Lact. fermentum and Lact. oris. The most commonly produced arylamidases active against substrates employed for testing human blood clotting cascade were activated protein C(Ca)-like, activated factor X(Xa)-like and Hageman factor-like followed by kallikrein-like and chymotrypsin-like enzymes.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Enzyme production by lactobacilli and the potential link with infective endocarditis. 769 50

Amyloid precursor protein forms that contain Kunitz protease inhibitor domains are released from activated platelets, T-lymphocytes, and leukocytes and inhibit trypsin, plasmin, and activated factor XI. We investigated the effects of amyloid precursor protein isoforms on activated Hageman factor (factor XII), activated factor X (Stuart factor), and thrombin. Recombinant amyloid precursor proteins with or without the Kunitz domain, 770 and 695 amino acids, respectively, were produced in insect cells by Baculovirus expression (BAC770 and BAC695). Neither BAC695 nor BAC770 inhibited human alpha-thrombin or activated factor X. The partial thromboplastin time was prolonged by both amyloid precursor proteins, only one of which, BAC770, contains the Kunitz protease inhibitor domain. Both forms of amyloid precursor proteins inhibited ellagic acid-induced activation of Hageman factor but did not inhibit activated Hageman factor. Bismuth subgallate, which is an insoluble analog of ellagic acid, lost its ability to activate Hageman factor on being exposed to BAC770. Inhibition of ellagic acid-induced activation of Hageman factor by both forms of amyloid precursor protein was enhanced by heparin. These findings suggested that the heparin-binding domain of amyloid precursor proteins is not in the Kunitz domain. This heparin-binding domain may block the activation of Hageman factor by negatively charged agents. Thus, amyloid precursor proteins may be involved in the control of hemostasis, properties not all dependent on the Kunitz domain.
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PMID:Inhibitory action of amyloid precursor protein against human Hageman factor (factor XII). 784 73

The prolonged partial thromboplastin time observed in the plasma of a 71-yr-old asymptomatic man was related to the deficiency of a hitherto unrecognized agent. The patient's plasma also exhibited impaired surface-mediated fibrinolysis and esterolytic activity and impaired generation of kinins and of the property enhancing vascular permeability designated PF/Dil. The patient's plasma contained normal amounts of all known clotting factors except Fletcher factor (a plasma prekallikrein) which was present at a concentration of 10-15% of pooled normal plasma. Fletcher trait plasma, however, contained normal amounts of the agent missing from the patient's plasma and corrected the defects in clotting, fibrinolysis, and vascular permeability. Fletcher trait plasma was less effective in correcting generation of kinins and esterolytic activity, presumably because of the patient's partial deficiency of prekallikrein. The site of action of the factor deficient in the patient's plasma appeared to be subsequent to the activation of Hageman factor and plasma prekallikrein. A fraction of normal plasma, devoid of other clotting factors, corrected the defect in clotting in the patient's plasma; a similar fraction of the patient's plasma did not correct this abnormality. No evidence yet exists pointing to the familial nature of the patient's defect. Tentatively, the patient's disorder may be referred to by his surname as Fitzgerald trait, and the agent apparently deficient in his plasma as Fitzgerald factor.
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PMID:Fitzgerald Trait: Deficiency of a Hitherto Unrecognized Agent, Fitzgerald Factor, Participating in Surface-Mediated Reactions of Clotting, Fibrinolysis, Generation of Kinins, and the Property of Diluted Plasma Enhancing Vascular Permeability (PF/Dil). 1669 63

Factor XII (FXII), also known as Hageman factor, is a coagulation protein that is necessary for the functioning of the intrinsic coagulation cascade and fibrin formation. When deficient, it results in a significant prolongation of activated partial thromboplastin time (aPTT), mimicking a bleeding disorder. However, it does not result in clinical bleeding tendency. We report a case of an elderly male who was found to have prolonged aPTT, discovered during preoperative evaluation for operative repair of hip fracture. Although laboratory investigation was suggestive of bleeding tendency, he was diagnosed with factor XII deficiency and had no bleeding complications intra-operatively or in the post-operative period.
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PMID:Factor XII Deficiency Mimicking Bleeding Diathesis: A Unique Presentation and Diagnostic Pitfall. 3012 21

Hageman factor (factor XII) has a key role in activation of intrinsic coagulation system gauged by activated partial thromboplastin time (aPPT). Hageman factor deficiency is more often an autosomal recessive condition, but an autosomal dominant inheritance is also reported. This condition in its own is not known to cause bleeding complications rather is associated with paradoxical fatal thromboembolic complications. Exact prevalence of this condition is not known, as under normal conditions they are asymptomatic. In literature, a prevalence of 2.3% has been reported in one study on 300 patients presenting with complications. Homozygous patients has non-detectable levels of factor XII, while heterozygous individuals has variable levels ranging from 20-60%. Hageman factor is a pro-coagulation protein initiating intrinsic pathway. Intrinsic pathway is activated either by direct contact with a negative charged surface or by proteolytic activation on the endothelial cells via prekallikerin/kallikerin system. Factor XII as an integral part of this system leads to factor XI activation resulting in production of thrombin orchestrated by intrinsic system. In addition, there is concomitant activation of complement components C3 and C5 via C1-estrase activation. Patients with this condition are known to have spontaneous thromboembolic complications although less common but are prone to life threatening complications under provocating circumstances. The aim of this case report is to study the relation of factor XII deficiency and isolated raised activated partial thromboplastin time (aPPT) and how it can be prevented. We are presenting a Saudi female patient, 29 years of age who presented to accident and emergency room (A&E room) of our hospital with sudden severe breathlessness and chest pain.
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PMID:Factor XII (Hageman Factor) Deficiency: a rare harbinger of life threatening complications. 3138 54


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