Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Hemophilia B is an X-linked coagulopathy caused by absence of functional coagulation factor IX (FIX). Using adeno-associated virus (AAV)-mediated, liver-directed gene therapy, we achieved long-term (> 17 months) substantial correction of canine hemophilia B in 3 of 4 animals, including 2 dogs with an FIX null mutation. This was accomplished with a comparatively low dose of 1 x 10(12) vector genomes/kg. Canine FIX (cFIX) levels rose to 5% to 12% of normal, high enough to result in nearly complete phenotypic correction of the disease. Activated clotting times and whole blood clotting times were normalized, activated partial thromboplastin times were substantially reduced, and anti-cFIX was not detected. The fourth animal, also a null mutation dog, showed transient expression (4 weeks), but subsequently developed neutralizing anti-cFIX (inhibitor). Previous work in the canine null mutation model has invariably resulted in inhibitor formation following treatment by either gene or protein replacement therapies. This study demonstrates that hepatic AAV gene transfer can result in sustained therapeutic expression in a large animal model characterized by increased risk of a neutralizing anti-FIX response.
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PMID:Sustained phenotypic correction of hemophilia B dogs with a factor IX null mutation by liver-directed gene therapy. 1267 97

The recent discovery that vitamin E (VE) regulates gene activity at the transcriptional level indicates that VE may exert part of its biological effects by mechanisms which may be independent of its well-recognised antioxidant function. The objective of this study was the identification of hepatic vitamin E-sensitive genes and examination of the effects of VE on their corresponding biological endpoints. Two groups of male rats were randomly assigned to either a VE-sufficient diet or to a control diet deficient in VE for 290 days. High-density oligonucleotide microarrays comprising over 7000 genes were used to assess the transcriptional response of the liver. Differential gene expression was monitored over a period of 9 months, at four different time-points, and rats were individually profiled. This experimental strategy identified several VE-sensitive genes, which were chronically altered by dietary VE. VE supplementation down-regulated scavenger receptor CD36, coagulation factor IX and 5-alpha-steroid reductase type 1 mRNA levels while hepatic gamma glutamyl-cysteinyl synthetase was significantly up-regulated. Measurement of the corresponding biological endpoints such as activated partial thromboplastin time, plasma dihydrotestosterone and hepatic glutathione substantiated the gene chip data which indicated that dietary VE plays an important role in a range of metabolic processes within the liver.
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PMID:Identification of hepatic molecular mechanisms of action of alpha-tocopherol using global gene expression profile analysis in rats. 1515 15

Increased risk of bleeding during oral anticoagulant (OA) treatment may be related to mutations in the precursor of coagulation factor IX. Missense mutations at Ala-10 (Ala-10Thre and Ala-10Val) in the factor IX propeptide lead to impaired carboxylation of factor IX. When patients carrying these mutations are treated with coumarins, functional factor IX levels decrease significantly, leading to an excessively prolonged activated partial thromboplastin time (aPTT) and an increased bleeding risk. Mutations at Ala-10 have been described in northern-European patients, but it is not known whether geographical differences play a role in the prevalence of these mutations. We aimed to analyze the prevalence of mutations at Ala-10 in factor IX in southern-European patients on OA treatment. Patients attending the Oral Anticoagulant Unit of the Hospital Clinic were prospectively included. The aPTT was determined at their normal International Normalized Ratio (INR) control. When the aPTT was excessively prolonged for the INR value, determination of factor IX and genotyping for Ala-10 mutations was performed. A total of 2360 patients were included (1289 men, 1071 women; mean age, 70.5 +/- 12.1 years). Twenty-four patients (16 men, eight women; mean age, 61.0 +/- 16.2 years) had an aPTT over that expected for the INR. The mean aPTT was 69.6 +/- 16.2 s. Only one patient presented with a factor IX level lower than 10%. None of the 24 patients carried mutations at Ala-10. Mutations at Ala-10 in factor IX were non-existent in the southern-European population analyzed, and thus, do not represent a relevant cause of bleeding during OA treatment.
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PMID:No impact of factor IX Ala-10 mutations in acenocoumarol-treated southern Europeans. 1626 29

There has been substantial progress in using gene therapy to treat animals with hemophilia. Adeno-associated viral (AAV) gene transfer of coagulation factor IX to skeletal muscle and liver of murine and canine models of hemophilia has resulted in sustained systemic expression and, in several studies, in complete cure of the bleeding disorder. Two AAV vectors widely used at present are AAV-CMV-F.IX and AAV-EF1alpha-F.IX. This work compares the predicted molecular functions of AAV-CMV-F.IX and AAV-EF1alpha -F.IX by sequence docking and gene ontology. It is shown that both AAV-CMV-F.IX and AAV-EF1alpha -F.IX induce coagulation factor IXa activity; however, AAV-CMV-F.IX administration also yields coagulation factor XIa activity and AAV-EF1alpha -F.IX treatment results in coagulation factor Xa activity. Therefore, AAV-CMV-F.IX might be useful for factor XI deficiency. AAV-CMV-F.IX has several additional molecular functions and processes compared with AAV-CMV-F.IX.
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PMID:Functions of AAV-CMV-F.IX And AAV-EF1alpha-F.IX in gene therapy for hemophilia B. 1726 22

Hemophilia B is a congenital recessive disorder caused by deficiency of coagulation factor IX (FIX). Surgical procedures can be performed in patients with hemophilia using high-purity and/or recombinant FIX, which has been shown to be safe and effective in surgical hemostasis. Liver transplantation is the only potentially curative treatment available for these patients, providing a long-term phenotypic cure for hemophilia. End-stage liver disease together with hemophilia exposes patients to greater risks of bleeding complications during the perioperative period with consequent difficulties in managing coagulopathy. The limited experiences reported by different investigators and the various strategies for clotting factor replacement make it difficult to define a single approach with respect to the optimal dose and method of administering FIX to achieve perioperative hemostasis. The limits of plasma-based coagulation tests--prothrombin time, activated partial thromboplastin time--have made thromboelastography a valid alternative in this kind of surgery. It has been demonstrated to be a useful tool for real-time analysis of clot formation using a whole-blood assay format. Further, it accurately illustrates the clinical effects of procoagulant or anticoagulant interventions. In this article, we have described the usefulness of thromboelastography to monitor the ability of high-purity FIX supplementation to restore a normal coagulation state and to guide the perioperative administration of blood products in a successful orthotopic liver transplantation in a hemophilic patient with deficiencies of factors IX and X, presenting with hepatitis C virus-related cirrhosis and hepatocellular carcinoma.
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PMID:Use of recombinant factor IX and thromboelastography in a patient with hemophilia B undergoing liver transplantation: a case report. 1867 36

Anticoagulant mechanism of the coagulation factor IX/factor X-binding protein (IX/X-bp) isolated from the venom of Trimeresurus flavoviridis was investigated. IX/X-bp had no effect on the amidase activity of factor Xa measured with a synthetic peptide substrate Boc-Leu-Gly-Arg-pNA. Prothrombin activation by factor Xa without cofactors, such as factor Va and phospholipids, was only slightly influenced by IX/X-bp. However, prothrombin activation by factor Xa in the presence of factor Va resulted in IX/X-bp inhibiting the increase of k(cat) of thrombin formation through inhibition of interaction between factor Xa and factor Va. IX/X-bp also inhibited the decrease of K(m) for thrombin formation through interaction with phospholipids. Thus, IX/X-bp appears to act as an anticoagulant protein by inhibiting the interaction between factor Xa and its cofactors in the prothrombinase complex by binding to the Gla domain of factor Xa.
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PMID:Anticoagulant mechanism of factor IX/factor X-binding protein isolated from the venom of Trimeresurus flavoviridis. 1897 69

Anticoagulation factor II (ACF II) isolated from the venom of Agkistrodon acutus is a member of the coagulation factor IX/coagulation factor X-binding protein (IX/X-bp) family. ACF II forms a 1:1 complex with activated coagulation factor X in a Ca(2+)-dependent fashion and thereby blocks the amplification of the coagulation cascade. In the present study, we have investigated the effect of ACF II on the mean arterial blood pressure (MABP) and heart rate (HR) in anaesthetized rats. The results indicate that ACF II induces a dose-dependent response in rats with a short fast drop of MABP followed by an increase and then a longer lasting slight decrease in MABP, but does not obviously affect HR. ACF II-induced hypotension is significantly blocked by the nitric oxide (NO) synthase inhibitor N-omega-L-arginine methyl ester (L-NAME). ACF II produces a concentration-dependent relaxation of rat aortic rings with functional-endothelium. The ACF II-induced vasodilatation is completely inhibited by removal of endothelium and significantly inhibited by pretreatment with L-NAME. These observations demonstrate that ACF II induces hypotension through an endothelium-dependent vasodilation, which is strongly mediated by the release of NO from endothelium. ACF II exhibits high anticoagulation activity in vivo based on activated partial thromboplastin time assay. Therefore, ACF II is so far identified as the first unique bifunctional protein in the IX/X-bp family that has both anticoagulant and hypotensive effects on the blood of rats through different pathways.
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PMID:Identification of a nitric oxide-dependent hypotensive effect of anticoagulation factor II from the venom of Agkistrodon acutus. 1972 11

This study was planned for searching possible changes of the total coagulation and fibrinolysis system in inflammatory bowel disease (IBD) in order to obtain some clues for explaining the relation between IBD and hypercoagulability. A total of 24 patients with ulcerative colitis, 12 patients with Crohn disease, and 20 healthy controls were studied. Platelets; prothrombin time (PT); partial thromboplastin time (PTT); fibrinogen; D-dimer; fibrinogen degradation products; protein C; protein S; antithrombin; thrombin time; von Willebrand factor; coagulation factors V, VII, VIII, IX, XI, and XIII; plasminogen; antiplasmin; tissue plasminogen activator; plasminogen activator inhibitor 1; and prothrombin fragments 1 + 2 were studied. Most of the procoagulants (platelets, fibrinogen, von Willebrand factor, coagulation factor IX, and plasminogen activator inhibitor 1) were found increased together with decreases in some anticoagulants (protein S and antithrombin) in IBD. Also the activation markers of coagulation (D-dimer, fibrinogen degradation products, and prothrombin fragments 1 + 2) were all increased. The parameters of the total coagulation-fibrinolysis system were increased in IBD, regardless of the form and the activity of the disease.
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PMID:Continuous active state of coagulation system in patients with nonthrombotic inflammatory bowel disease. 2159 18

Haemophilia B is an X-linked recessive bleeding disorder caused by mutations in the F9 gene on Xq27.1, which lead to deficient coagulation factor IX (FIX). The mild form of haemophilia B has been known to be underdiagnosed due to mild clinical symptoms and minimally prolonged activated partial thromboplastin time. We herein describe a sporadic case of mild haemophilia B from a novel missense mutation of F9. The proband was a 4-year-old boy with a mild bleeding history. He had no family history of bleeding tendency. Coagulation screening tests revealed prolonged aPTT at 42.6s (STA-PTT Automate, reference range, 29.1-41.9s) and a decreased FIX activity at 13% in factor assays. Molecular genetic analysis of F9 revealed that he was hemizygous for a missense mutation, c.1048T>G (p.Ser350Ala), which has not been reported previously. His mother was a carrier of the mutation. This case represents a novel missense mutation from non-CpG transversion of F9.
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PMID:Mild haemophilia B from a novel missense mutation Ser350Ala of the F9 gene. 2349 13


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