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Results for “Factor XII Deficiency”

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At least 253 records · Page 14Linked to original sources
PubMed1995

Amidolytic assay of factor XI in human plasma--significance of kallikrein for the activity measured.

Factor XI (FXI) deficiency is associated with an abnormal bleeding state. The extent of bleeding does not correlate well with the plasma concentration of FXI, and it has been suggested that also unknown factors interfere with the bleeding tendency. In a recent paper (Thromb. Res. 74, 477-485, 1994) we found that FXIa activated in human plasma was present in association with part of factor XIIa (FXIIa) and part of kallikrein, influencing their functional activities. Should the activity level of FXIa also be altered by the other contact factors this might provide one approach to the problem of the failure of assays of FXIa to correlate with bleeding tendency. In the present study we have developed an assay procedure for FXIa based on its amidolytic (S-2366) activity, and allowing at the same time a quantification of the amount of FXIa associated to kallikrein. The total amidase activity obtained was separated into two main fractions by use of soybean trypsin inhibitor (STI), corn inhibitor (CI) and lima bean trypsin inhibitor (LTI). One fraction contained free FXIa which could be specifically blocked by LTI. An inhibitor resistant fraction was found to contain FXIa inactive in association with kallikrein. The content of FXIa could be assessed in experiments with mixtures of normal plasma and plasma deficient in prekallikrein, and was taken into account in the calculations. This fraction increased during storage of plasma at -70 degrees C. To obtain stable and comparable assay conditions the method was based on plasma stored for at least four weeks. The specificity of the method was verified by parallel radial immunodiffusion tests. The results imply that the activity level of FXIa is dependent on kallikrein present. If the experimental results has relevance to the situation under physiological conditions, they indicate one possible cause of the failure of assays of FXI to correlate with bleeding tendency.

Adult↗
PubMed1996

Studies of the platelet filter test (shear dependent platelet aggregation) in patients with uncommon haemorrhagic disorders.

Platelets of anticoagulated whole blood forced at 40 mmHg through a fine filter are activated, aggregated and retained, so block the filter (platelet filter test, O'Brien JR, Salmon GP. Blood 1987; 1354-1361). Our clinical experiences with this simple and quick haemostasis test are summarized. Patients were investigated with different types of vWD (type-1 = 35, type-2A = 7, type-2B = 7, type-3 = 1), Glanzmann's thrombasthenia, congenital deficiency of cyclo-oxygenase, acquired Bernard-Soulier syndrome, FXII-, FXIII-deficiency and a control group. The cumulative drop count and the platelet retention were carefully measured during two phases of the filter test. Platelet count, bleeding time, vWF:Ag and vWF:Rcof activity were measured along with the platelet filter test. The filter was not blocked and the platelet retention was abnormally low in all patients with thrombasthenia, type-2a, type-2B, type-3 vWD. Treatment with 1-desamino-8-D-arginine-vasopressin (DDAVP) caused enhanced platelet retention in 16 patients with type-1 vWD. The test is simple, quick and cheap, has good reproducibility, and may be useful in clinical haemostasis laboratories for examination of high shear induced platelet functions.

Adolescent↗
PubMed1986

The contact activation system: biochemistry and interactions of these surface-mediated defense reactions.

This review is intended to be a critical state-of-the-art overview of the activation and inhibition of the proteins (factor XII, prekallikrein, high molecular weight kininogen, and factor XI) of the contact phase of coagulation. Specifically, this review will reconsider the concept of the reciprocal activation of the proteases of the contact phase of coagulation, factor XII, and prekallikrein, in light of much recent evidence indicating that factor XII, itself, autoactivates when associated with negatively charged surfaces. In addition, the mechanisms for amplification of activation of the proteins of the contact phase of coagulation will be discussed from the pivotal role of high molecular weight kininogen, or one of its altered forms, serving as a cofactor to order the activation of the zymogens it is associated with. The role and relative importance of each of the naturally occurring plasma protease inhibitors (C1-inhibitor, alpha-2-macroglobulin, alpha-1-antitrypsin, antithrombin III, and alpha-1-antiplasmin) will be assessed as they relate to the dampening of contact phase activation. Finally, the contact phase of coagulation activation will be discussed not only as a plasma proteolytic mechanism, but also as it interacts with platelets.

Blood Coagulation↗
PubMed1980

Immunoquantitation of Hageman factor in urine and plasma of children with nephrotic syndrome.

Children with nephrotic syndrome frequently have decreased plasma levels of Hageman factor (factor XII). Studies were designed to determine whether this finding results primarily from a loss of Hageman factor in the urine or is related to an alteration in the Hageman factor protein itself. A monospecific anti-Hageman factor goat antibody was prepared and used for quantitative measurements of Hageman factor in urine and plasma by a radial immunodiffusion method. Samples of 24 hr urine collections from 14 children with nephrotic syndrome were examined by this immunoassay technique; no Hageman factor was detected in the urine in 13/14 patients. Comparative studies using plasma from the nephrotic syndrome patients and nine normal controls demonstrated: (1) a significantly reduced level of Hageman ACT in the nephrotic syndrome patients (p < 0.001); (2) a reduction to a lesser degree of the levels of CRM in the same group (p < 0.001); and (3) a significantly increased CRM/ACT ratio in the plasma of the patients with nephrotic syndrome (p < 0.01) indicating partial inactivation of the Hageman factor enzymatic function. However, no inhibitory activity to added Hageman factor could be detected in the plasma or urine of the patients. These findings indicate that the decreased plasma Hageman factor activity that accompanies the nephrotic syndrome cannot be adequately explained by simple urinary loss of Hageman factor as has previously been suggested.

Adolescent↗
PubMed1998

Transcatheter closure of atrial septal defect and patent foramen ovale with ASDOS device (a multi-institutional European trial).

A clinical trial was conducted to assess the feasibility, safety, and efficacy of the atrial septal defect (ASD) occlusion system for transcatheter closure of secundum ASD and patent foramen ovale (PFO) after episodes of cerebral embolism. Occlusion was attempted in 200 patients aged 1 to 74 years (mean 32). The procedure failed in 26 patients (13%); the device was retrieved through a catheter in 20 and through surgery in 6 patients. Procedure-related complications necessitating surgical removal of the device included device embolization in 2, device entrapment within the Chiari network in 1, frame fracture in 1, and perforation of atrial wall in 2. All 6 patients experienced an uneventful postoperative course. An additional 11 patients (6%) underwent surgical removal of the device during follow-up. There were 163 patients (81%) with an implanted ASD occlusion system at follow-up of from 6 to 36 months (mean 17). Thrombus formation around the device was detected by transesophageal echocardiography in 9 patients 1 to 4 weeks after implantation. One of these patients (who had a coagulation factor XII deficiency) suffered a cerebral thromboembolism. Late atrial wall perforation (5, 6, and 8 months after implantation) occurred in 3 adult patients. Infectious endocarditis developed in 2 adult patients (1%). No late device embolization and no atrioventricular valve injury occurred. An asymptomatic device frame fracture was found in 14% and frame deformity in 4% of all patients during the follow-up period of >230 patient-years. Immediately after closure, a moderate/large residual shunt remained in 8% and a small shunt in 29% of patients. After 1 year, a moderate/large shunt was present in 2% and a small one in 26% of patients. During a total follow-up of 49 patient-years, only 1 of 46 patients with PFO had a transient neurologic event after the closure. The study indicates that patients with centrally situated secundum ASD and those with PFO after cerebral embolism can be treated with this system with a high success rate and an acceptable morbidity.

Adolescent↗
PubMed1988

Inherited coagulation disorders.

Inherited coagulation disorders have been diagnosed in many breeds of dogs as well as in mongrels and cats. This article presents the different coagulation factor deficiencies that are known to exist in small animals. A description is given of each coagulation factor along with the relevant clinical signs, inheritance, and the breeds affected. Suggestions are also given for the diagnosis and therapy of these deficiencies.

Afibrinogenemia↗
PubMed1999

Treatment of hereditary and acquired thrombophilic disorders.

The treatment of hereditary and acquired thrombophilic disorders is based on an understanding of the disease pathophysiology, prevalence, associated morbidity and mortality, and available therapeutic options. Genetic mutations are identified that result in activated protein C (APC) resistance and hyperhomocyst(e)inemia. The underlying etiologies are less well-defined; however, the disorders of factor XII deficiency, dysfibrinogenemia, Wien-Penzing platelet defect, and sticky platelet syndrome (SPS) are treatable inherited thrombophilias. Antithrombin deficiency, protein C and protein S deficiencies, and plasminogen deficiency are disorders both inherited and acquired. Antiphospholipid antibodies, myeloproliferative syndromes, and Trousseau's syndrome are acquired. Treatment for acute arterial thrombosis or venous thromboembolism is the same or similar for all thrombophilic disorders. Long-term management is based on the risk of a primary or recurrent acute thrombotic event, compared with the risk of the proposed therapy. Few blinded, controlled studies are available to validate treatment recommendations. When long-term anticoagulation is advised, careful consideration should be given to the risk associated with therapy. Bleeding risk, variable efficacy, and the risk of cutaneous necrosis limit the use of warfarin. Fixed low-dose unfractionated porcine heparin and low-molecular-weight heparins (LMWH) offer significant advantages for long-term management. These recommendations are derived from an analysis of the pertinent medical literature and are expected to change with the progress of clinical and laboratory investigation.

Disease Management↗
PubMed1983

Thrombosis or myocardial infarction in congenital clotting factor abnormalities and chronic thrombocytopenias: a report of 21 patients and a review of 50 previously reported cases.

Nine patients are described with hereditary clotting factor abnormalities and thrombosis and 35 others previously reported in the literature. An additional 11 patients with myocardial infarction observed by the authors and 12 more reported by others are also included. A patient with non-immune thrombocytopenia and myocardial infarction is presented, as well as three additional patients recorded in the literature. This study underscores the little-recognized phenomenon of uncontrolled thrombosis in these patients with "experiments of nature," in whom clotting studies reflect an impairment of coagulation comparable in degree to that achieved by oral anticoagulant therapy.

Adult↗
PubMed2004

Ketanserin in women with chronic hypertension and underlying thrombophilia.

BACKGROUND: Pregnant women with chronic hypertension and thrombophilia have an increased risk for preeclampsia and/or intrauterine growth restriction (IUGR). Ketanserin lowers blood pressure and inhibits serotonin-induced platelet aggregation. CASES: A 38-year-old woman with chronic hypertension had a first pregnancy with severe hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome. A second pregnancy with prophylactic oral ketanserin and low-dose aspirin was uneventful. The third pregnancy without oral ketanserin was again complicated by severe superimposed preeclampsia and IUGR. During this pregnancy a prothrombin mutation was found. A 37-year-old woman with chronic hypertension developed severe early-onset superimposed preeclampsia in her first pregnancy. In the 3 consecutive pregnancies, she was treated with low-molecular-weight heparin because of a factor XII deficiency. Only the pregnancy with the use of prophylactic oral ketanserin was uncomplicated. CONCLUSION: Clinical trials are warranted to analyze the role of oral ketanserin in preventing preeclampsia and IUGR.

Adult↗