| 1. |
- 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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| 2. |
- Holst, Jan, et al.
(författare)
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The effect of protamine sulphate on plasma tissue factor pathway inhibitorreleased by intravenous and subcutaneous unfractionated and low molecularweight heparin in man
- 1997
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Ingår i: Thrombosis Research. - 0049-3848 .- 1879-2472. ; 86:4, s. 343-348
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Tidskriftsartikel (refereegranskat)abstract
- Heparin, a negatively charged sulphated glycosaminoglycan, is clinically the most important antithrombotic drug. Heparin augments the inhibitory activity of antithrombin (AT) towards thrombin, factor Xa (FXa) and other activated clotting enzymes. Tissue factor pathway inhibitor (TFPI) is an endogenous heparin releasable three domain Kunitz-type coagulation inhibitor which inhibits the crucial tissue factor-factor VIIa (TF-FVIIa) dependent coagulation pathway in the presence of FXa. The importance of the TF-FVIIa pathway and TFPI has recently been reviewed (1). TFPI is located to different vascular pools, the largest being the vascular endothelium from where TFPI can be released dose-dependently to the blood by heparins (2). TFPI is speculated to contribute to the anticoagulant properties of heparins, but to which degree is not yet fully understood. In recent years low molecular weight heparins (LMWH) have proven to be effective and safe both for prophylactic (3) and therapeutic treatment (4) of deep vein thrombosis (DVT). Protamine is the least toxic and clinically most commonly used antidote to heparin. However, in vitro and in vivo LMW heparinized blood is not fully neutralized by protamine, as substantial anti-Xa activity remains following neutralization (5). This post-protamine effect has been shown to be partly TFPI dependent when measured in a dilute TF-dependent assay (6,7). We undertook this in vivo study on healthy volunteers in order to investigate whether TFPI released by UH or LMWH (intravenous (iv) or subcutaneous (sc)) remains in the circulation following neutralization of the heparin activity with protamine sulphate (PS). We measured TFPI by three different methods-chromogenic activity, anticlotting activity and a new antigen assay specific for full-length and three-domain TFPI.
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| 3. |
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| 4. |
- Larsson, J, et al.
(författare)
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The prothrombin gene G20210A mutation and the platelet glycoprotein IIIa polymorphism PlA2 in patients with central retinal vein occlusion
- 1999
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Ingår i: Thrombosis Research. - : Elsevier BV. - 0049-3848. ; 96:4, s. 7-323
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Tidskriftsartikel (refereegranskat)abstract
- The prothrombin gene G20210A mutation and the platelet glycoprotein IIIa polymorphism PlA2 have been shown to be associated with thromboembolic disease. We wondered if mutations were overrepresented in patients with central retinal vein occlusion. We studied 129 consecutive patients with a history of central retinal vein occlusion. We analysed for the prothrombin gene G20210A mutation and the platelet glycoprotein IIIa polymorphism PlA2 and compared the results to controls with no history of thrombosis. For the platelet glycoprotein IIIa polymorphism PlA2, 69% were normal, 26% were heterozygous, and 5% were homozygous. For the G20210A prothrombin mutation, 97% were normal and 3% were heterozygous. Neither the prothrombin gene G20210A mutation nor the platelet glycoprotein IIIa polymorphism PlA2 seem to be associated with central retinal vein occlusion.
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| 5. |
- Ljung, R., et al.
(författare)
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Purification of F.VIII:C by antigen-antibody chromatography
- 1978
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Ingår i: Thrombosis Research. - : Elsevier BV. - 0049-3848. ; 12:4, s. 667-675
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Tidskriftsartikel (refereegranskat)abstract
- Purification of F.VIII:C devoid of F.VIII:Ag was achieved by antigen-antibody chromatography. The antibody used neutralized VIIIR:Ag but not VIII:C in liquid phase but extracted both VIII:Ag and VIII:C from plasma when bound to Sepharose. VIII:C was eluted with calcium-containing buffer. When plasma was used as starting material VIII:C was obtained free from VIIIR:Ag but contaminated with some other proteins. When a well-defined pure F.VIII preparation was used as starting material the VIII:C active fractions contained no immunoradiometrically detectable VIIIR:Ag, no VIIIR:RCF and no detectable protein. When stabilized with albumin VIII:C could be frozen and thawed with retained activity and could be activated with thrombin.
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| 6. |
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| 7. |
- Persson, E, et al.
(författare)
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Plasma lipolytic activity after subcutaneous administration of heparin and a low molecular weight heparin fragment
- 1987
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Ingår i: Thrombosis Research. - : Elsevier BV. - 1879-2472 .- 0049-3848. ; 46:5, s. 697-704
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Tidskriftsartikel (refereegranskat)abstract
- The effect of heparin and a low molecular weight heparin fragment (LMWH, mean molecular weight 4000-6000) on plasma anticoagulation and lipolysis was studied in eight healthy men. The activities of antifactor Xa (antiFXa), lipoprotein lipase (LPL), hepatic lipase (HL) and plasma levels of free fatty acids (FFA) were analysed after the injection of 5000 antiFXa units of heparin or LMWH subcutaneously. In comparison with heparin, the administration of LMWH resulted in a significantly higher antiFXa activity (p less than 0.001) but a lower release of LPL and HL (p less than 0.001), which did not increase plasma FFA. It is concluded that subcutaneous injection of LMWH in men elicits an adequate anticoagulant effect measured as antiFXa activity but has a negligible effect on plasma lipolytic activity.
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