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)

Evidence in the literature suggests that von Willebrand's disease constitutes part of a mesenchymal syndrome accompanied by coagulopathy. The cases of two patients with symptomatic intestinal angiodysplasia and concurrent von Willebrand's disease are summarized along with the eight cases previously reported in the literature. All ten cases were in adults ranging in age from 34 to 80 years (average, 58 years). The vascular lesions were located in the stomach or duodenum (four cases), right colon (three cases), and terminal ileum (two cases). One patient had angiodysplasia of the stomach, jejunum, and sigmoid colon. While the prevalence is unknown, these ten cases linking gastrointestinal angiodysplasia with von Willebrand's disease appear to reflect an association greater than more coincidence. Coagulation testing, including determination of template bleeding time and partial thromboplastin time, should probably be performed in all patients bleeding from gastrointestinal angiodysplasia to screen for von Willebrand's disease.
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PMID:Gastrointestinal angiodysplasia: a possible component of von Willebrand's disease. 660 74

Intravenous adrenalin infusion (5 micrograms/kg, at most 160 micrograms in 10 min) normalized partial thromboplastin time (PTT) and ristocetin induced platelet aggregation (RIPA) in 4 of the 14 patients with von Willebrand's disease (VWD) in a short period of time. Although mean factor VIII (F-VIII) procoagulant activity was almost doubled 5 min following infusion, this was mainly observed in patients with relatively high baseline (> 2%) AHF activity. Mean F-VIII procoagulant activity rose by more than 100% following 10 days of corticosteroid treatment (deltacortil 2 mg/kg/day, at most 60 mg/day). PTT became normal in 6 of the 11 patients, but RIPA normalized only in 2. The improvement of RIPFA did not correspond to bleeding time in every patient. These results may suggest that if the baseline AHF activity is relatively high (greater than or equal to 9.5%), corticosteroid could be tried before schedule surgical intervention in patients with VWD.
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PMID:Effect of intravenous adrenalin infusion and corticosteroid treatment in patients with von Willebrand's disease. 677 88

A 10-month-old Simmental heifer was examined because of a 10-day history of epistaxis and aural hematomas. Examination of the calf also revealed hemarthrosis. Initial laboratory data indicated that platelet count, platelet size, prothrombin time, and partial thromboplastin time were not different from a clinically normal (control) cow. Mucosal bleeding time was prolonged, and platelet adhesion to glass beads was less than expected. The clinical signs, prolonged bleeding time, and platelet adhesion defect were corrected by infusion of bovine plasma. Subsequent laboratory testing revealed that the affected calf had a truncated multimeric structure of von Willebrand factor (vWF), low vWF activity, and impaired platelet aggregation in response to adenosine diphosphate, but concentration of vWF was not different from that in clinically normal control animals. These data were consistent with a diagnosis of variant von Willebrand disease. The relationship of this disease to the thrombopathy of Simmental cattle is unclear.
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PMID:Bleeding diathesis associated with variant von Willebrand factor in a Simmental calf. 774 52

Three male German Shepherd Dog pups were treated for vaccination-induced hematomas. Coagulation tests in 2 of these pups revealed markedly prolonged activated partial thromboplastin times, whereas specific coagulation factor tests revealed severe deficiency of factor IX activity. Investigation of the pedigree supported a sex-linked pattern of inheritance and a distant relationship to a pup found to have hemophilia B 7 years earlier. Dogs in the pedigree had variable manifestations of bleeding, including hematomas, deep muscle bleeding, profuse bloody diarrhea, and sudden neonatal deaths. von Willebrand's disease was concurrently detected in several dogs in the pedigree, and may have contributed to the bleeding tendency in some dogs. Medical management of 2 of the 3 pups included transfusion of fresh whole blood, canine fresh-frozen plasma, and canine plasma cryosupernatant, as indicated, and cage rest. Two pups were euthanatized because of the severity of recurrent bleeding episodes. A third dog remains alive, but requires periodic infusions of blood product to maintain hemostasis.
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PMID:Hemophilia B (factor IX deficiency) in a family of German shepherd dogs. 779 Mar 4

The purpose of this prospective study in patients undergoing tonsillectomy was to determine whether perioperative bleeding could be predicted by use of a standardized questionnaire concerning bleeding risk combined with measurement of the activated partial thromboplastin time and prothrombin time. Of the 96 patients enrolled in the study, none had a history of a severe bleeding disorder, but 6 (6%) had histories suggestive of a mild bleeding disorder. Further evaluation showed possible von Willebrand's disease in one of these patients. Of the 90 patients with negative questionnaires, 16% had prolongation of the activated partial thromboplastin time. One of these patients had possible von Willebrand's disease. However, none of the patients with positive questionnaires or a prolonged activated partial thromboplastin time bled after surgery. Bleeding that resulted in additional hospital use occurred in 2% of patients, and blood-tinged sputum was described by 4% after discharge; all of these patients had negative questionnaires and normal screening studies. The data provide further evidence that routine measurement of the activated partial thromboplastin time and prothrombin time in asymptomatic patients is not useful for predicting postoperative bleeding. In addition, histories suggestive of a mild bleeding disorder are also not accurate predictors of postoperative bleeding. Excessive bleeding associated with tonsillectomy is usually not a result of an identifiable coagulation disorder.
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PMID:Hemostatic assessment of patients before tonsillectomy: a prospective study. 799 Dec 52

Von Willebrand's disease (vWD) is the most common inherited bleeding disorder. Typical clinical features such as bleeding after surgery or trauma might suggest the disease. We present a series of 24 patients with vWD treated between 1989 and 1992. Diagnosis was confirmed by a reduction in plasma factor VIII antigen concentration, reduction of ristocetin cofactor activity and reduced factor VIII activity. Seventeen of the patients underwent surgery (7 adenoidectomies, 8 tonsillectomies, 2 paranasal sinus operations) and received preoperative stimulation of von Willebrand factor (vWF) using DDAVP. This resulted in a rapid increase in plasma vWF concentration from an average of 56% before stimulation to 190% of the normal value after stimulation. A reduction of partial thromboplastin time from an average of 44.4 seconds to 34.4 seconds was observed following DDAVP. No bleeding complications or other side-effects occurred. Preoperative stimulation of vWF using DDAVP proved to be a safe method to reduce the risk of bleeding in patients with vWD undergoing surgery.
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PMID:[Von Willebrand syndrome--risk of hemorrhage in ENT interventions in childhood]. 806 Apr 55

Factor VIII is an important cofactor in the intrinsic activation of factor X. To function effectively as a cofactor, factor VIII must be activated. In plasma, factor VIII circulates in a complex with von Willebrand factor, and although thrombin can activate complexed factor VIII, the activation by activated factor X is inhibited by von Willebrand factor. In this study, the effect of von Willebrand factor on the generation of factor Xa by the factor IXa-VIII complex was investigated. Purified human factors VIII, IXa, and X were incubated on human umbilical vein endothelial cells or phospholipid vesicles in the presence of calcium ions, and the generation of factor Xa was followed. In the presence of von Willebrand factor, a prolonged lag-phase and a dose-dependent inhibition of factor X activation was observed. These effects were not observed when von Willebrand factor was preincubated with a monoclonal antibody directed against von Willebrand factor that blocks factor VIII binding. When factor VIII was activated with thrombin before the incubation, neither the monoclonal antibody nor von Willebrand factor had an effect on the rate of factor X activation. Preincubation of endothelial cells with the monoclonal antibody resulted in a somewhat higher rate of factor X activation. When endothelial cells from a patient with von Willebrand's disease type I were used, preincubation of the monoclonal antibody had no effect on the rate of factor X activation. We conclude that von Willebrand factor on the surface of endothelial cells can modulate the intrinsic factor X activation. This effect is greatly enhanced, however, by the addition of exogenous von Willebrand factor.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:von Willebrand factor as a regulator of intrinsic factor X activation. 814 7

A Saudi Arabian family is reported in which Glanzmann's thrombasthenia and von Willebrand's disease occurred simultaneously. The daughter presented with menorrhagia and gave a history of gastrointestinal bleeding and a strong family history of bleeding disorder. Full haematological investigations were performed on the propositus, parents, and siblings, including complete blood count, bleeding time, prothrombin time, partial thromboplastin time, factor VIII:C, von Willebrand factor, ristocetin cofactor, platelet aggregometry, platelet glycoprotein Ib and IIb/IIIa and platelet antigen PLT-1 (Coulter Clone). The propositus had Glanzmann's thrombasthenia, both parents had mild von Willebrand's disease and were carriers of Glanzmann's thrombasthenia. Three symptomatic brothers had both Glanzmann's thrombasthenia and von Willebrand's disease; two asymptomatic brothers had von Willebrand's disease only and one had completely normal results. Those family members with both diseases were more severely affected than those with just one disease. In areas where consanguineous marriage is common, such as Saudi Arabia, multiple haemostatic abnormalities may occur, and investigation should not stop with the discovery of a single abnormality. The increased clinical severity of bleeding, including haemarthroses, in those patients having both congenital defects emphasises the importance of von Willebrand factor in glycoprotein Ib-mediated platelet adhesion.
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PMID:Glanzmann's thrombasthenia with mild von Willebrand's disease. 828 41

1. The effects of venous occlusion on the coagulation and fibrinolytic systems were investigated in six patients with type 1 (insulin-dependent) diabetes and 11 age- and sex-matched non-diabetic control subjects. The coagulation parameters (fibrinogen, prothrombin time, partial thromboplastin time with kaolin, von Willebrand factor antigen) did not differ between patients and control subjects either before or after 20 min of venous occlusion. No rise was observed in von Willebrand factor antigen after venous occlusion in either group. 2. In the diabetic patients, chronic activation of the fibrinolytic system was found at baseline, which was indicated by a shortened euglobulin lysis time (P < 0.01), increased tissue plasminogen activator activity (P < 0.05) and decreased plasminogen activator inhibitor type 1 antigen level (P < 0.05), when compared with control subjects. In both groups venous occlusion resulted in significant increments in all measurements, except plasminogen activator inhibitor type 1 antigen level. The post-occlusion values did not differ between the two groups, except the plasminogen activator inhibitor type 1 antigen level, which remained significantly lower in the diabetic patients. The mean increments in each parameter did not differ between the two groups. 3. Coagulation and fibrinolysis were assessed in response to acute insulin-induced hypoglycaemia. Von Willebrand factor antigen levels increased significantly in both groups, with no difference in maximal increments. Significant activation of the fibrinolytic system occurred in response to hypoglycaemia, demonstrated by shortened euglobulin lysis time and increased fibrin plate lysis, tissue plasminogen activator antigen level and tissue plasminogen activator activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Coagulation and fibrinolytic systems in type I diabetes: effects of venous occlusion and insulin-induced hypoglycaemia. 838 39

We report a family with a combined factor VII Padua defect and von Willebrand's disease (vWd). The propositus is a 9-year-old child with a moderate bleeding tendency who appeared to be heterozygous for both factor VII Padua and type I vWd. The diagnosis of factor VII Padua was based on a normal factor VII antigen and factor VII activity which was low with rabbit brain thromboplastin but normal with ox brain thromboplastin. Type I vWd was diagnosed because of a concomitant decrease of von Willebrand factor antigen (vWf:Ag) and vWf ristocetin-cofactor activity (vWf:RCoF), associated with the presence of vWf multimers of all sizes in plasma and platelets. The parents were not consanguineous but came from the same isolated river Piave valley in North Eastern Italy where the factor VII Padua defect was first described. The father had the factor VII Padua defect but was clinically asymptomatic in accordance with the heterozygous state. The propositus's mother had type I vWd and was mildly symptomatic. The propositus' sisters, who were clinically asymptomatic, were both heterozygotes for factor VII Padua. The infusion of DDAVP normalized the factor VIII/vWf pattern in all patients. In the propositus, in contrast to the mother and normal subjects, showed a more rapid clearance both of vWf and factor VIII. The same pattern, albeit to a lesser degree, was also observed in the father.
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PMID:First report of combined factor VII Padua defect and von Willebrand's disease due to casual association of the two defects. 845 48


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