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)

Acquired hemophilia A is a life-threatening immune-mediated hemorrhagic disorder that is most often found in individuals older than 50 who present with an unexplained activated partial thromboplastin time (aPTT) prolongation and clinically significant bleeding. The prolonged aPTT associated with acquired hemophilia A reflects factor VIII activity deficiency due to neutralizing or clearing autoantibodies. Deep venous thrombosis, in contrast, is a veno-occlusive disorder associated with several distinct hypercoagulable states that can result in significant morbidity and mortality due to pulmonary embolism, thrombus extension, and the post-thrombotic syndrome. A prolonged aPTT in the setting of thrombosis may reflect the presence of a lupus anticoagulant. In the absence of accurate diagnosis and the immediate institution of specific therapy, both disorders can be fatal. Three cases of acquired factor VIII inhibitors that included a prolonged aPTT, bleeding, and duplex ultrasound evidence of deep venous thrombosis are presented. The diagnostic and therapeutic challenges posed by these cases as well as a proposed mechanism by which pathologic thrombosis can develop in a patient with a life-threatening bleeding disorder are discussed.
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PMID:Simultaneous deep venous thrombosis and acquired factor VIII inhibitor. 1251 88

The hemostatic process initiated by the exposure of tissue factor to blood is a threshold limited reaction which occurs in two distinct phases. During an initiation phase, small amounts of factor (F)Xa, FIXa and thrombin are generated. The latter activates the procofactors FV and FVIII to the activated cofactors which together with their companion serine proteases form the intrinsic FX activator (FVIIIa-FIXa) and prothrombinase (FVa-FXa) which generate the bulk of FXa and thrombin during a propagation phase. The clotting process (fibrin formation) occurs at the inception of the propagation phase when only 5-10 nM thrombin has been produced. Consequently, the vast majority (greater than 95%) of thrombin is produced after clotting during the propagation phase of thrombin generation. The blood of individuals with either hemophilia A or hemophilia B has no ability to generate the intrinsic FXase, and hence is unable to support the propagation phase of the reaction. Since clot based assays conclude before the propagation phase they are not sensitive to hemophilia A and B. The inception and magnitude of the propagation phase of thrombin generation is influenced by genetic polymorphisms associated with thrombotic and hemorrhagic disease, by the natural abundance of pro- and anticoagulants in healthy individuals and by pharmacologic interventions which influence thrombotic pathology. Therefore, it is our suspicion that the performance of the entire process of thrombin generation from initiation through propagation and termination phases of the reaction are relevant with respect to both hemorrhagic and thrombotic pathology.
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PMID:What is all that thrombin for? 1287 Dec 86

Hemophilia A is relatively rare and the number of patients with this disorder who undergo surgery is limited. We herein report a surgical case of bilateral pneumothorax accompanied by mild deficiency type of hemophilia A. Although this patient had undergone major surgery at another institution, a diagnosis of hemophilia A had not been made, nor had he noticed unusual bleeding in his daily life. Laboratory studies showed a slight prolongation of the activated partial thromboplastin time. A thoracoscopic operation was performed for bilateral pneumothorax in 1996. After the initial operation, the blood discharge from the right thoracic drainage tube continued. Despite two reoperations, oozing from the chest wall could not be controlled. Finally, the patient had achieved a stable condition with hemothorax encompassing the right thorax. After a diagnosis of hemophilia A was made, we removed any coagulated blood while administering a factor VIII preparation. Clinical and laboratory indications in daily life of mild deficiency type hemophilia A are not manifest in comparison with those of severe or moderate types. It is therefore necessary to consider this disorder in cases of abnormal bleeding at or after operation.
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PMID:Bilateral pneumothorax accompanied by mild deficiency type hemophilia a: report of a case. 1460 59

The monitoring of coagulation-inhibitor bypassing agents, including recombinant factor VIIa (rFVIIa), remains a major issue in the management of clinical hemophilia. Clotting assays using prothrombin time (PT) and measurements of factor VII (FVII) activity do not always reflect the hemostatic effects of treatment. Thrombelastography can be used to observe the global effects of treatment on the overall coagulation process and is especially useful for observing the effects of hemostatic treatment in hemophilia patients with inhibitors. Waveform analysis is another technique for evaluating global hemostatic condition where changes in light transmission during routine clotting assays, such as the activated partial thromboplastin time (aPTT), are measured. We found that waveforms differed between individual patients with severe hemophilia A (FVIII:C < 1.0 IU/dL) with levels of sensitivity at below FVIII:C 1.0 IU/dL. Clot waveforms indicated dose-dependent improvements in clot formation after the addition of rFVIIa to both FVIII-deficient and factor IX (FIX)-deficient plasma. The improvements were further enhanced in the presence of both platelets and synthetic phospholipids, and were more pronounced with FVIII-deficient plasma than with FIX-deficient plasma. It appears that clot waveform analysis provides a very useful means for monitoring hemostasis in hemophilia A patients with inhibitors.
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PMID:Understanding the hemostatic effects of recombinant factor VIIa by clot wave form analysis. 1487 33

A case of sporadic hemophilia A in a young child was investigated from a molecular biology point of view. The propositus is a 4-year-old severe hemophiliac who was first seen when he was 2 years old. At that time, easy bruising and hematomas were noted because of accidental falls while toddling. The coagulation study showed a prolonged partial thromboplastin time and a factor VIII level of 1.3% of normal. Molecular biologic analysis showed a large deletion involving intron 13 up to exon 23. In the inversion study, the propositus exhibited only a 10 kb band, and this result suggests that intron 22 was deleted while his mother shows a normal pattern. To further examine the length of the deletion, a long polymerase chain reaction by means of primers amplifying the region from exon 13 to 23. In the index patient, an approximate 13-kb product was obtained, whereas no product was obtained from his mother. The mother investigated by means of polymorphism was shown not to be a carrier.
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PMID:A large deletion due to a new mutation (intron 13/exon 23) in a sporadic case of severe hemophilia A. 1497 7

A 54-year-old man presented with unconsciousness. Computed tomography revealed acute subdural hematoma. Emergency evacuation of hematoma was performed showing any excessive tendency to bleed or difficulty to stop bleeding during the operation. However transfusion of fresh frozen plasma was needed to stop continuous bleeding from the surgical wound after the operation. The patient underwent craniotomy again 18 days after the operation because he suffered hemorrhagic infarction and recurrence of acute subdural hematoma. After the second operation, a coagulability examination revealed that his activated partial thromboplastin test was prolonged (74.5 seconds) and his plasma factor VIII level was 20% of normal, so he was diagnosed as having mild hemophilia A. Cranioplasty was accomplished with replacement therapy, and he was discharged with mild recent memory disturbance and homonymous hemianopsia.
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PMID:[A surgical case of subdural hematoma with hemophilia A]. 1552 90

Activated recombinant human factor VIIa (rFVIIa) has been used as a hemostatic agent in patients with hemophilia and acquired inhibitors. Other indications for rFVIIa may include liver disease, warfarin sodium (Coumadin) overdose, or trauma. Monitoring patients on this treatment with standard laboratory testing is problematic. Bleeding risk does not correlate well with the prothrombin time (PT) or the activated partial thromboplastin time (aPTT) during therapy with rFVIIa. In addition, there is no identifiable literature on the effect of rFVIIa on assays of inhibitors in this patient group. Monitoring inhibitors may be important during interventions aimed at acutely reducing inhibitor levels, such as during plasma exchange or protein adsorption. We performed factor assays and evaluated inhibitor levels in plasma from 3 patients with deficiencies in FVIII (2 patients) or FIX (1 patient) and inhibitors (titer range, 5.8-17.4 Bethesda units) before and after adding rFVIIa (range, 0.25-8 microg/mL) in vitro. Additionally, we performed assays of factors of both intrinsic and extrinsic systems to determine the impact of rFVIIa on these tests. We found that both factor levels and inhibitor titers from patients with hemophilia A or B could be measured accurately, even in the presence of suprapharmacologic doses of rFVIIa (8 microg/mL). We also obtained accurate measurements for other assays of the intrinsic coagulation system (FXI and FXII) based on the aPTT. Conversely, we found that assays of the extrinsic system based on the PT (FII, FV, and FX) produced results that were unreliable. FVII results were very high but reproducible. These results suggest that assays based on the PT are inaccurate and should be avoided during FVIIa treatment. Conversely, FVIII and FIX levels and inhibitor titers can be accurately monitored in hemophilia patients receiving rFVIIa according to results of aPTT-based coagulation tests.
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PMID:Effect of activated recombinant human factor 7 (Niastase) on laboratory testing of inhibitors of factors VIII and IX. 1602 35

Aminoglycoside antibiotics exhibit their bactericidal effect by interfering with normal ribosomal activity. In this pilot study, we have evaluated the effect of the aminoglycoside antibiotic gentamicin on the factor VIII (FVIII) and IX levels of severe hemophiliacs with known nonsense mutations. Five patients were enrolled and each patient was given 3 consecutive days of gentamicin at a dose of 7 mg/kg intravenously every 24 hours. Two patients (patient no. 1: hemophilia A, Ser1395Stop; and patient no. 5: hemophilia B, Arg333Stop) showed a decrease in their activated partial thromboplastin time (aPTT), an increase in their FVIII (0.016 IU/mL, 1.6%) or FIX (0.02 IU/mL, 2%) levels, and an increase in thrombin generation. The remaining 3 patients (patient no. 2: hemophilia B, Arg252Stop; patient no. 3: hemophilia A, Arg2116Stop; and patient no. 4: hemophilia A, Arg427Stop) showed no response in the aPTTs or factor levels, but one (patient no. 2: hemophilia B, Arg252Stop) showed an increase in the factor IX antigen level (2%-5.5%) that persisted throughout the period of the study and was concordant with an increase in thrombin generation. Gentamicin is unlikely to be an effective treatment for severe hemophilia due to its potential toxicities and the minimal response documented in this report. This study, however, does provide a proof of principle, suggesting that ribosomal interference with a less toxic agent may be a potential therapeutic mechanism for severe hemophilia patients with nonsense mutations.
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PMID:Aminoglycoside suppression of nonsense mutations in severe hemophilia. 1605 41

Hemophilia A is a congenital bleeding disorder characterized by a deficiency of coagulation factor VIII. Intramural hematoma of the colon is a very rare complication of this disease. We report a case of intramural hematoma of the cecum serving as the lead point of intussusception in a 65-year-old man with hemophilia A. The patient presented with right-sided abdominal pain and bloody stool. Palpation of his abdomen revealed a fist-sized mass. Abdominal computed tomography (CT) showed a circular mass with concentric rings, consistent with an intussuscepted intestine. Because his activated partial thromboplastin time (APTT) was prolonged, we gave him a continuous infusion of factor VIII during and after surgery. Laparotomy revealed an irreducible colo-colic intussusception and we identified a cecal hematoma as the lead point. After an unsuccessful attempt at Hutchinson's maneuver, we performed right colectomy. We report this case to illustrate the necessity of monitoring APTT in patients with hemophilia A who undergo surgery.
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PMID:Intramural hematoma of the cecum as the lead point of intussusception in an elderly patient with hemophilia A: report of a case. 1671 31

A 66-year-old man with hypertension and hyperlipidemia developed a hemorrhagic stomal ulcer and massive hematoma of the face at 4 and 7 months, respectively, after fundusectomy for early gastric cancer. The diagnosis of acquired hemophilia A was made based on the marked prolongation of activated partial thromboplastin time, an extremely low factor VIII activity, and a very high-titer factor VIII inhibitor. After admission, oral prednisolone and cyclophosphamide were started. In addition, activated prothrombin complex concentrates and recombinant activated factor VII were intravenously administered which successfully controlled his hemorrhage. Only 1 week after the episode of bleeding, however, he complained of abdominal pain accompanied by watery stool with fresh blood. The diagnosis of ischemic colitis was made based on the clinical course and the findings on both CT-scan and colon fiberoscopy. The colitis spontaneously and quickly resolved with conservative observation. To the best of our knowledge, this is the first reported case of ischemic colitis that occurred in an acquired hemophilia patient without simultaneous administration of coagulation factors or antifibrinolytic agents. We should thus pay attention to the possible occurrence of thrombotic events even in acquired hemophilia patients in the presence of risk factors for thrombosis.
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PMID:[Ischemic colitis following the treatment of acute hemorrhage in a patient with acquired hemophilia A]. 1671 66


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