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Results for “Factor XI Deficiency”

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PubMed1981

The role of HF cofactor in the Hageman factor-dependent fibrinolytic mechanism.

In 1969, Ogston et al. reported that the normal activation of fibrinolysis by surface contact requires, in addition to Hageman factor and plasminogen, a HF cofactor which is present in the euglobulin fraction and other factor(s) present in the supernatant. It has also been suggested that the glass-treated plasma is deficient in HF cofactor, In our laboratory the glass-treated plasma was found not to be deficient in HF or in a streptokinase-activated proactivator or in plasminogen. The glass-treated plasma was found deficient in prekallikrein in kininogen and in clotting factors XI, IX, VIII and V. The results presented indicate that HF cofactor activity is not different from that of kallikrein and that HF cofactor does not act as a plasminogen proactivator. Furthermore, the results indicate that the "other factors' present in the supernatant are not involved in contact-activated fibrinolysis.

Blood Coagulation Factors↗
PubMed2003

Retrospective analysis of 1312 patients with haemophilia and related disorders in a single Chinese institute.

With 1.3 billion people, China has the largest population in the world, and therefore has the largest population of persons with haemophilia (PWH). As there is no national registry for haemophilia, it is difficult to ascertain how many PWH have actually been diagnosed. Between January 1983 and June 2002, 1312 patients with coagulation disorders were referred to our hospital, and 1190 patients were evaluable. Among them, 1069 (89.8%) patients had haemophilia, 68 had vWD, 20 had factor XI deficiency, 10 had acquired factor VIII inhibitor and 23 had other coagulation disorders. Of the 1069 PWH, 14.7% were unclassified, 38.4% severe, 35.7% moderate and 11.1% mild. If the unclassified cases were excluded, 45.1% were severe, 41.9% moderate and 13.0% mild. Twenty-nine of the 68 vWD patients had vWF:Ag <5%, and subcategorized as type 3 vWD. Because vWF multimer analysis was not performed in our centre, the remaining vWD patients were not subdivided.

Adolescent↗
PubMed2002

Clinical and laboratory features of 178 children with recurrent epistaxis.

PURPOSE: To determine the clinical and laboratory features of 178 children referred for the evaluation of recurrent epistaxis to an outpatient hematology clinic in a university medical center. PATIENTS AND METHODS: Medical records of 3681 outpatient pediatric hematology referrals were retrospectively review, and 178 children with recurrent epistaxis from 1985 to 1999 were identified. Historic (other bleeding symptoms: gingival bleeding, easy bruising, menorrhagia, and gross blood in the urine or stool: duration and severity of the epistaxis episodes; and family history of bleeding) and laboratory (complete blood count and coagulation tests) data were analyzed. RESULTS: There were 103 boys and 75 girls with a median age of 84 months (range 15-219 months). Sixty-seven percent (n = 119) did not have a coagulopathy diagnosed and 33% (n = 59) did. The diagnoses included von Willebrand disease in 33, platelet aggregation disorders in 10, thrombocytopenia in seven, mild factor VIII deficiency in three, Bernard-Soulier syndrome in two, factor VII deficiency in one, factor IX deficiency in one, and factor XI deficiency in one, and coagulation inhibitor in one. Of the historic data, only a family history of bleeding was predictive of diagnosing a coagulopathy (P = 0.023). The duration and severity of the epistaxis and the presence of other bleeding symptoms had no predictive value. Children with a coagulopathy diagnosed had a longer median partial thromboplastin time (PTT) (33.1 vs. 30.5 seconds; P = 0.012). CONCLUSIONS: One-third of children presenting with recurrent epistaxis have a diagnosable coagulopathy. A positive family history and a prolonged PPT are useful predictive data.

Adolescent↗
PubMed1979

Reduction of salivary tissue factor (thromboplastin) activity by warfarin therapy.

The coagulant of normal human saliva has been identified as tissue factor (thromboplastin, TF) by virtue of its ability to cause rapid coagulation in plasmas deficient in first-stage coagulation factors and to activate factor x in the presence of factor VII and by virtue of the fact that its activity is expressed only in the presence of factor VII and is inhibited by an antibody to TF. The TF is related to cells and cell fragments in saliva. Salivary TF activity has been found to be significantly reduced in patients taking warfarin. The decline in TF activity during induction of warfarin anticoagulation occurs during the warfarin-induced decline in vitamin-K-dependent clotting factor activity, as judged by the prothrombin time. The decrease in TF activity is not related to a reduction in salivary cell count or total protein content or to a direct effect of warfarin on the assay. It is hypothesized that the mechanism by which warfarin inhibits TF activity may be related to the mechanism by which it inhibits expression of the activity of the vitamin-K-dependent clotting factors. Inhibition of the TF activity may be involved in the antithrombotic effect of warfarin.

Factor VII↗
PubMed1981

Alternative pathways of thromboplastin-dependent activation of human factor X in plasma.

To determine the interrelationships of the major coagulation pathways, the activation of 3H-labeled factor X in normal and various deficient human plasmas was evaluated when clotting was triggered by dilute rabbit or human thromboplastin. Various dilutions of thromboplastin and calcium were added to plasma samples containing 3H-factor X, and the time course of factor X activation was determined. At a 1/250 dilution of rabbit brain thromboplastin, the rate of factor X activation in plasmas deficient in factor VIII or factor IX was 10% of the activation rate of normal plasma or of factor XI deficient plasma. Reconstitution of the deficient plasmas with factors VIII or IX, respectively, reconstituted normal factor X activation. Similar results were obtained when various dilutions of human thromboplastin replaced the rabbit thromboplastin. From these plasma experiments, it is inferred that the dilute thromboplastin-dependent activation of factor X requires factors VII, IX, and VIII. An alternative extrinsic pathway that involves factors IX and VIII may be the physiologic extrinsic pathway and hence help to explain the consistent clinical observations of bleeding diatheses in patients deficient in factors IX or VIII.

Animals↗
PubMed2006

Targeting coagulation factor XII provides protection from pathological thrombosis in cerebral ischemia without interfering with hemostasis.

Formation of fibrin is critical for limiting blood loss at a site of blood vessel injury (hemostasis), but may also contribute to vascular thrombosis. Hereditary deficiency of factor XII (FXII), the protease that triggers the intrinsic pathway of coagulation in vitro, is not associated with spontaneous or excessive injury-related bleeding, indicating FXII is not required for hemostasis. We demonstrate that deficiency or inhibition of FXII protects mice from ischemic brain injury. After transient middle cerebral artery occlusion, the volume of infarcted brain in FXII-deficient and FXII inhibitor-treated mice was substantially less than in wild-type controls, without an increase in infarct-associated hemorrhage. Targeting FXII reduced fibrin formation in ischemic vessels, and reconstitution of FXII-deficient mice with human FXII restored fibrin deposition. Mice deficient in the FXII substrate factor XI were similarly protected from vessel-occluding fibrin formation, suggesting that FXII contributes to pathologic clotting through the intrinsic pathway. These data demonstrate that some processes involved in pathologic thrombus formation are distinct from those required for normal hemostasis. As FXII appears to be instrumental in pathologic fibrin formation but dispensable for hemostasis, FXII inhibition may offer a selective and safe strategy for preventing stroke and other thromboembolic diseases.

Animals↗
PubMed1991

Inherited bleeding disorders.

Congenital bleeding disorders comprise a heterogeneous group of diseases that reflect abnormalities of blood vessels, coagulation proteins and platelets. Studies of these diseases, many of which are rare and several of which result in a mild bleeding diathesis only, have significantly increased our understanding of normal haemostasis. Two lessons have been learned. First, quantitative abnormalities of coagulation proteins and platelets are an important, but not the only, cause of significant haemorrhage; some cases of inherited bleeding disorders reflect synthesis of a dysfunctional coagulation protein or production of abnormal platelets. Diagnostic tests that reflect qualitative abnormalities are therefore important in the evaluation of selected patients with inherited bleeding disorders. Second, in occasional patients the inherited disorder is complex and reflects combined abnormalities of coagulation proteins alone or in association with platelet disorders. In clinical practice it is useful to distinguish disorders that cause significant clinical bleeding from those that cause few or no symptoms. Examples of the former include severe deficiencies of factors VIII and IX, and the homozygous forms of factor II, V, VII, X, XI, XIII, fibrinogen and von Willebrand factor. Comparable platelet disorders include the inherited thrombocytopenias with platelet counts less than 20 x 10(9) litre-1 and the homozygous forms of Bernard-Soulier syndrome and Glanzmann's thrombasthenia. The most frequently encountered mild haemostatic abnormalities include type I von Willebrand's disease, the platelet storage pool deficiency syndromes and the mild and moderate forms of haemophilia A and B; occasionally heterozygous or homozygous forms of the rarer coagulation disorders, e.g. factor XI deficiency, may present with a mild bleeding diathesis. Finally, some disorders are entirely asymptomatic, e.g. factor XII deficiency and deficiencies of other contact coagulation factors. Management of patients with inherited bleeding disorders should reflect knowledge of the specific disorder to be treated plus careful consideration of the clinical circumstance for which therapy is proposed. In all cases, once a decision to treat has been made, the safest efficacious therapy should be given (for example DDAVP in the treatment of patients with mild haemophilia A or type I von Willebrand's disease). Although blood products are now much safer and the risk of blood transmitted viral infections is low, there still remains a risk that transfusion of any blood product may be associated with serious side-effects. As a result, therapy should be given only after careful consideration of the risk: benefit ratio and not merely to treat an abnormal laboratory result.(ABSTRACT TRUNCATED AT 400 WORDS)

Afibrinogenemia↗
PubMed1990

[Isolated prolongation of the PTT: 2-year retrospective study].

The hemorrhagic risk associated with isolated prolongation of the PTT has been evaluated in a 2-year retrospective study. Of the 60 cases thus found, a hemorrhagic risk was present in 15 patients of whom 7 had hemophilia A, 5 von Willebrand's disease and 3 factor XI deficiency. Among the other etiologies not associated with a bleeding tendency, there were 31 proved or suspected cases with inhibitors of the PTT, most of whom were children, 2 factor XII deficiencies, 2 prekallikrein deficiencies and 4 contact phase activations. Isolated prolongation of the PTT is therefore without specificity and needs further investigation of hemostasis to determine the associated hemorrhagic risk.

Factor XI Deficiency↗
PubMed1977

Activation of factor IX by the reaction product of tissue factor and factor VII: additional pathway for initiating blood coagulation.

A study was carried out on mechanisms, independent of activated Factor XI, capable of activating Factor IX. The reaction product of tissue factor and Factor VII functioned as a potent Factor IX activator in the assay system used. Activated Factor IX itself activated Factor X; thrombin failed to activate Factor IX. Sodium dodecyl sulfate/polyacrylamide gel electrophoresis confirmed that the reaction product of tissue factor and Factor VII activated Factor IX, with replacement of the band corresponding to native factor IX [molecular weight (Mr) 55,000] by bands corresponding to the heavy chain (Mr 27,000) and light chain (Mr 17,000) of activated Factor IX. When either Factor VII or calcium ions were left out of incubation mixtures, the band of native Factor IX persisted unchanged. Contact of blood with tissue factor represents a second mechanism, bypassing activated Factor XI, for the activation of Factor IX during hemostasis. It may help to explain the discrepancy between the mild bleeding of hereditary Factor XI deficiency and the severe bleeding of hereditary Factor IX deficiency.

Animals↗
PubMed1990

Correction of facial deformities in patients with mild bleeding disorders: a report of three cases.

A bleeding diathesis need not be a contra-indication to elective surgical correction of facial deformities. Preoperative haemostatic assessment and management of haemostasis during and after surgery is described. Two cases of mild von Willebrand's disease and one case of factor XI deficiency who successfully underwent orthognathic surgery for the correction of facial deformities are reported.

Adolescent↗
PubMed1991

Platelet and coagulation studies in Ehlers-Danlos syndrome.

Fifty-one patients with Ehlers-Danlos syndrome were investigated for abnormalities of platelets and coagulation. Thirty-eight were examined prospectively and 13 retrospectively. A bleeding history was taken from all patients; only four (8%) gave no history of a bruising or bleeding tendency. Nine patients (18%) had significant haemostatic abnormalities of whom four (8%) had a platelet release defect, three (6%) had a factor XI deficiency and two (4%) had a factor XIII deficiency. Additionally 16 patients (31%) had mild abnormalities of uncertain significance of whom four (8%) had prolonged bleeding times (three in association with platelet aggregation abnormalities), 13 (26%) had platelet aggregation abnormalities and two had a positive Hess test. Twenty-four patients (47%) had normal tests for haemostasis of whom 20 (39%) had a bleeding diathesis and four (8%) had no such tendency. Results were analysed according to the type of Ehlers-Danlos syndrome, but there was no pattern to the abnormalities. The high frequency of a bleeding tendency in Ehlers-Danlos patients with normal tests for haemostasis (83%) supports the conventional explanation for this clinical feature, that defects in the structural integrity of skin and blood vessels lead to easy bruising.

Adolescent↗
PubMed1992

Rare inherited bleeding disorders secondary to coagulation factors in Jordan: a nine-year study.

This work reports on rare inherited coagulation factors defects which were seen in a developing country over a 9-year period. There were a total of 30 cases which fulfilled this diagnosis. Fibrinogen abnormalities were the most frequently encountered. There were 10 patients with afibrinogenemia, 2 with hypofibrinogenemia and 1 case with dysfibrinogenemia. Factor XI deficiency was found in 7 patients, factor V and VII deficiencies accounted for 3 cases each. Factor X and XIII deficiencies were found in 2 patients each. All these rare deficiencies accounted for 10% of all inherited bleeding disorders in the population studied over 9 years.

Blood Coagulation Disorders↗