| 1. |
- Holmberg, Lars, et al.
(författare)
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Prenatal diagnosis of hemophilia B by an immunoradiometric assay of factor IX
- 1980
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Ingår i: Blood. - 0006-4971. ; 56:3, s. 397-401
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Tidskriftsartikel (refereegranskat)abstract
- An immunoradiometric assay of factor IX was developed based on homologous antibodies that arose in a hemophilic patient. With this assay, 11 of 12 patients with severe hemophilia B had factor IX antigen levels below 1 U/dl and 6 patients with mild hemophilia B had various levels. Factor IX antigen in 8 fetuses (16th-20th gestational week) aborted for therapeutic reasons ranged from 1.8 to 10.0 U/dl. Six amniotic fluids contained 0.28-1.2 U/dl factor IX antigen. Using the immunoradiometric assay, we could diagnose hemophilia B prenatally in one fetus at risk. No factor IX antigen (< 0.2 U/dl) was detectable in the fetoscopic sample. After termination of the pregnancy, analysis of blood from the abortus confirmed the diagnosis of severe hemophilia B. We conclude that very sensitive immunologic assays, such as the one described here, will prove useful in prenatal diagnosis of severe hemophilia B, since determination of factor IX activity in fetoscopic samples is unrealiable because of possible contamination with thromboplastic material.
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| 2. |
- Holmberg, Lars, et al.
(författare)
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The effects of plasmin and protein Ca on factor VIII:C and VIII:CAg
- 1983
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Ingår i: Thrombosis Research. - : Elsevier BV. - 0049-3848. ; 31:1, s. 41-50
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Tidskriftsartikel (refereegranskat)abstract
- The effects of various concentrations of plasmin and activated protein C on the factor VIII procoagulant activity (VIII:C) and coagulant antigen (VIII:CAg) were studied in factor VIII concentrates and normal plasma. Small amounts (0.1 CTA U/ml) of plasmin rapidly destroyed VIII:C, and affected, but did not destroy VIII:CAg, in factor VIII concentrates. In normal plasma larger amounts of plasmin (1.8 CTA U/ml) was required to inactivate VIII:C in order to exceed the neutralizing capacity of alpha 2-antiplasmin. VIII:CAg was unchanged indicating a limited proteolysis. The difference between VIII:C and VIII:CAg was found also in urokinase-activated plasma. Activated protein C (5 micrograms/ml), in the presence of Ca2+ and phospholipids, inactivated VIII:C without affecting VIII:CAg in a high purity factor VIII concentrate. Higher concentrations of activated protein C (25 micrograms/ml) caused a slight decrease of VIII:CAg, even in the absence of Ca2+ and phospholipids, but did not change VIII:CAg in normal plasma or serum.
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| 3. |
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| 4. |
- Ljung, R, et al.
(författare)
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Inheritable molecular variants of moderate and mild hemophilia A
- 1981
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Ingår i: Acta Medica Scandinavica. - 0001-6101. ; 209:1-2, s. 11-16
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Tidskriftsartikel (refereegranskat)abstract
- Factor VIII clotting activity (VIII:C) and factor VIII clotting antigen (VIII:CAg) were investigated in 54 patients with hemophilia A of moderate or mild severity. The patients belonged to 28 kindreds. The study showed a genetically determined molecular variation within hemophilia A of both moderate and mild forms. Each form can be classified into 3 types according to the content of demonstrable VIII:CAg. Type I has no demonstrable VIII:CAg, type IIa has VIII:CAg in an amount smaller than, or approximately equal to, that of VIII:C and type IIb has a larger amount of VIII:CAg than VIII:C. Affected members of one and the same kindred always have the same type of the disease.
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