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Query: UMLS:C0684275 (haemophilia)
 10,958 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Difficulties in the detection of haemophilia A carriers by the determination of the ratio factor VII coagulation activity to factor VII antigen concentration are shown in part one of our investigations. The second part evaluates methodical parameters of the quantitative immunoelectrophoretic technique. According to our results reliable data can only be obtained under the following conditions: 1. At least three determinations of each sample are required and the mean value should be used as the final result. 2. Each gel plate should be calibrated separately 3. The calibration line should include values less than 100%. Factor VIII concentrates are not suitable for determination of the calibration curve, as higer dilution results in lower calculated concentration of the undiluted concentrate. Storage of pooled normal plasma at--25 degrees C is possible without significant loss of antigen concentration over 5 months. However, plasma samples of a single person show an unpredictable variation in the antigen concentration during storage over the same time.
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PMID:[Problems of conductor demonstration in haemophilia A: error possibilities in the determination of factor-VIII-associated antigen]. 6 59

A fluid-phase immunoradiometric assay has been developed which identifies an antigen on the Factor VIII (antihemophilic factor) procoagulant protein. This sensitive and quantitative assay is not influenced by levels of Favor VIII-related antigen (von Willebrand factor) or other plasma proteins. There is a close correlation of procoagulant activity and immunologically detectable protein in normal and von Willebrand's disease plasmas. In contrast, several different patterns have been identified in hemophilic plasmas. Neither procoagulant activity nor procoagulant antigen is detectable in plasmas from patients with severe classic hemophilia. Patients with mild and moderate hemophilia have either comparable plasma concentrations of procoagulant activity and procoagulant antigen or relatively greater levels of immunologically detectable protein.
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PMID:Immunoradiometric measurement of the factor VIII procoagulant antigen. 8 38

Factor VIII is a complex molecule comprising a series of homologous oligomers with biological activity related to primary haemostasis (factor VIII related antigen/Willebrand factor; FVIIIRAg/WF). The structure or distribution of these oligomers is abnormal in von Willebrand's disease (vWd). The oligomers are associated with, or contain, a lower molecular weight entity with procoagulant activity (factor VIIIC) which has distinct antigenic determinants and is reduced or abnormal in haemophilia. Recessive and dominant forms of vWd have been recognised but two families are described each with features of both dominant and recessive inheritance; this is of importance in genetic counselling. Results of a new immunoradiometric assay for factor VIIIC antigen showed reduced levels in vWd and haemophilia and it was absent in 3 of 6 samples from fetuses of obligate carriers of haemophilia. The potential use of this assay for the prenatal diagnosis of haemophilia is described.
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PMID:Factor VIII: new clinical and genetic aspects. 9 Mar 82

The incidence of post-transfusion hepatitis and liver dysfunction is presented in fifty-four patients with classical hemophilia who received episodic and/or prophylactic Factor VIII concentrate. 42.5% had persistent biochemical evidence of liver dysfunction with elevated SGOT and SGPT; 3.8% have persistent (HBs) antigenicity and 90% have (HBsAb) antibodies. The results are the same for those who were treated episodically and received an average of 753 units Factor VIII per week as those treated prophylactically who received an average of 686 Factor VIII units per week. The incidence of clinical and/or subclinical disease is unaffected by the transfusion regimen or the amount of concentrate used. The necessity for close follow is emphasized for determination of chronic liver disease and its further therapy.
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PMID:Liver dysfunction in patients with hemophilia. 26 1

The effect of the enzymes phospholipases C and D on Factor VIII were investigated. Phospholipase D was found to activate the partially purified intact Factor-VIII molecule maximally at a final concentration of 0.6 U/ml. Neither the dissociated small molecular weight component nor the high molecular weight component were activated. Phospholipase C, on the other hand, inactivated both the intact and the dissociated Factor-VIII molecule. Phospholipase D, however, had no effect on the haemophilic cryoprecipitate or the partially purified haemophilic Factor VIII. The implications of these results for the genetic control of the Factor-VIII molecule are discussed. In this connection, haemophilia A is hypothesized to be caused by an X-linked enzyme effect that impairs phospholipid assembly of the Factor-VIII protein, whereas von Willebrand's disease might be due to a structural defect of the Factor-VIII protein.
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PMID:Effect of phospholipases on factor-VIII activity. 30 30

Antihemophilic factor (Factor VIII) is an agent in normal plasma that corrects the coagulative defect of classic hemophillia. The plasma of hemophiliacs contains normal amounts of a variant of antihemophilic factor deficient in clot-promoting properties. In contrast, von Willebrand's disease is usually associated with a true deficiency of this protein. In this disorder, the platelets are poorly aggregated by ristocetin, a defect ascribed to deficiency of antihemophilic factor. Structural studies of antihemophilic factor suggest that it is composed of two dissociable subcomponents, one of high molecular weight that contains the bulk of protein and sustains ristocetin-induced platelet aggregation, and another of lower molecular weight with procoagulant activity. Both subcomponents have been identified in hemophilic plasma, as if the smaller subcomponent were qualitatively abnormal. Carriers of hemophilia can often be detected because their plasmas contain a disproportionately high concentration of antihemophilic factor, measured immunologically, compared with the titer of procoagulant antihemophilic factor.
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PMID:Antihemophilic factor (factor VIII). 34 83

The predictive odds for suspected carriers of hemophilia have been calculated using data derived from normal and known carrier populations. For each individual, the concentration of Factor VIII-related antigen and Factor VIII biological (procoagulant) activity was measured and the data were studied by linear discriminant analysis. Forty-five suspected carriers were evaluated, with 31 percent (14/45) classified as carriers. Using Factor VIII procoagulant activity alone, 18 percent (8/45) appeared as carriers, while the ratio method of activity level to antigen level showed 44 percent (20/45).
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PMID:Experience in the laboratory detection of the carrier state of classic hemophilia. 43 79

Factor VIII (fVIII) activity and antigenicity were determined on replicate fresh blood samples drawn on three separate occasions in 48 normal females and 37 obligatory haemophilia A carriers, in an attempt to improve the detection rate. fVIII activity was assayed by a one-stage method and fVIII antigenicity by the Laurell's technique employing an anti-fVIII antiserum prepared in rabbits. The mean results for the individual subjects were analysed after establishing a discriminant function. The probability of being a carrier was determined on the basis of laboratory data and family history. The probability data were translated into more simple terms applicable for genetic counselling by defining three categories: Definite carriers, doubtful carriers and definite normals. Of the obligatory carriers, 83.8% were classified definite carriers, 13.5% doubtful carriers and 2.7% as definite normals. Of the normal females, 4.2% were classified as definite carriers, 18.7% doubtful carriers and 77.1% as definite normals. Adjustment of the results according to age was found unnecessary. The precision of the determinations of fVIII antigenicity and fVIII activity in individual subjects was calculated for different numbers of replicate tests performed in the same individual. It was found that if only one test is performed, a substantial error might occur. Three replicate tests considerably diminish this error, although it is still in the range of +/- 16--29%. For suspected carriers who fall in the doubtful category it is suggested that six or even more tests are performed.
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PMID:Detection of Haemophilia A carriers by replicate factor VIII activity and factor VIII antigenicity determinations. 47 99

Factor VIII inhibitor levels were measured on 261 occasions in 76 hemophilia-A inhibitor patients before and after prothrombin complex concentrate infusion at 13 treatment centers. A rise in inhibitor level to at least twice the pretreatment value occurred in 35 treatment episodes (13.5%), in 27 patients (36%). In 16 patients (21%), such an anamnestic immune response occurred with the first treatment. Factors predisposing to anamnestic responses may include patient idiosyncrasy, low pretreatment inhibitor levels, and exposure to concentrate over several days.
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PMID:Effect of prothrombin complex concentrates on factor VIII inhibitor levels. 50 42

Fanconi's anaemia and haemophilia A are born inherited diseases creating haemostatic defects. The association of these two rare diseases in one patient is described. The patient's haemophilia was studied with a newly developed immunological technique determining the plasma antigen associated with Factor VIII activity, and was found to be a genetic variant of moderately severe haemophilia A. It was not possible to demonstrate a common bone marrow defect or a common immunological or genetical background of the two diseases. The double haemostatic defect created, i.e. Factor VIII deficiency and thrombocytopenia, resulted in only a slight increase in bleeding tendency. A favourable result was obtained with corticosteroid and androgenic treatment.
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PMID:Fanconi's anaemia associated with haemophilia A. 51 7


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