摘要:

Methods for the assay of antifactor Xa activity in the presence and absence of heparin are described. Diluted plasma is incubated with bovine, activated factor X (Xa) in stage I and remaining Xa is measured with the chromogenic substrate Bz-Ile-Glu-Gly-Arg-pNA in stage II. In the presence of heparin, the inactivation is completed in 30 sec, and this method measures total Xa-inactivating capacity in diluted plasma (Method I). In a clinical material, this capacity showed a strong positive correlation (r = 0.85) to the thrombin-inacti-vating capacity of diluted heparinized plasma (heparin cofactor activity) and apparently reflects antithrombin III (At-III) concentration. In the absence of heparin, the inactivation of factor Xa occurs slowly. With an incubation of 5 min, about 25 % of Xa is inactivated, and this assay reflects initial inactivation of Xa (Method II). With this method, a positive, but less strong correlation to the throm-bin-inactivating capacity was found (r = 0.58), indicating that inhibitors different from At-III accounts for a minor part of the initial inactivation. Determinations in plasma, in which At-III was removed by immunoadsorption, indicated that At-III accounts for about 80% of the initial inactivation. The results of the assays are not significantly influenced by varying concentrations of fibrinogen, fibrinogen degradation products or heparin in the test plasma.

ISSN:1424-8832    

DOI:10.1159/000214145

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

A girl with symptoms of von Willebrand’s disease was found to have a slightly reduced or normal FVIII procoagulant activity, normal FVIII-related antigen (VIIIR :AG) and virtually absent von Willebrand’s factor. The electrophoretic mobility of the VIIIR :AG in this patient’s plasma and plasma fractions was increased and has been compared with that of two reported patients with FVIII variants. Her lysed platelets contained increased amounts of VIIIR:AG, which had an increased anodal migration identical to her plasma VIIIR: AG. Experiments involving the selective absorption of a rabbit antiserum with the patient’s plasma provide evidence that VIIIR :AG and von Willebrand’s factor are immunologically

ISSN:1424-8832    

DOI:10.1159/000214146

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

Soluble fibrin monomer complexes (SFMC) were determined in patients with septic abortion (body temperatures of more than 39 °C and/or chills without apparent signs of endotoxic shock), with infected abortion, with non-infected abortion and with normal pregnancies. Quantitative gel filtration (4% agarose) of β-alanine precipitated plasma samples yielded the relative (percent of total fibrinogen content) and absolute (mg/l00 ml plasma) amount of SFMC. The relative (5.5 ± 1.4%, mean ± SD) and absolute (21.5 ± 8.6 mg/l00 ml) amount of SFMC was significantly increased in patients with septic abortion compared to patients with normal pregnancies or non-infected abortion (p < 0.001). Patients with infected abortion already revealed increased levels of SFMC (4.3 ± 1.2%, 14.2 ± 6.8 mg/l00 ml) though their platelet count was still unaltered (infected abortion: 221 ± 47 × 103 platelets/mm3; septic abortion: 99 ± 36 × 103 platelets/mm3). The use of heparin in patients with septic abortion resulted in a decrease in SFMC. Chain characterization of SFMC frequently revealed a slight degradation of the α-chains probably due to fibrinolytic activity in vivo; γ-γ dimers representing inter-molecular covalent bindings were not observed. The findings are in agreement with our former assumption that patients with septic abortion have a pronounced state of hyper

ISSN:1424-8832    

DOI:10.1159/000214147

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

It has previously been shown, that large differences exist between the effects of 6-aminohexanoic acid or α1-antitrypsin on fibrinolysis caused by a porcine tissue plasminogen activator or by human urokinase, while insignificant differences exist between the effects of a number of natural protease inhibitors on fibrinolysis caused by the two types of plasminogen activator. The present study shows that changes in substrate composition (pH, ionic strength, fibrinogen concentration, plasminogen concentration) may influence to different degrees the fibrinolytic activities of human urokinase and the porcine tissue plasminogen activator. It is suggested, that this finding is partly related to marked differences in affinity for fibrin of the two activators

ISSN:1424-8832    

DOI:10.1159/000214148

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

Defective ADP-induced aggregation was observed in in vitro streptokinase (SK)-treated normal platelet-rich plasma. Classic haemophilia and normal platelet-poor plasmas (PPP) treated with SK inhibit the aggregation of washed platelets; plasmin-treated normal human serum also shows an inhibitory effect on platelet aggregation. However, SK-treated von Willebrand plasmas do not inhibit the aggregation of washed platelets. This confirms the fact that the anti-aggregating effect is mainly linked to the digested factor VIII but not to the digested fibrinogen. Defective ristocetin-induced platelet aggregation has also been observed in SK-treated plasmas. The presence of normal PPP does not modify the inhibition of the ADP-induced aggregation of washed platelets in SK-treated PPP. However, it does correct the ristocetin-induced aggregation. These results suggest that the inhibition of the ADP-induced aggregation is caused by the factor VIII degradation products, while the inhibition of the ristocetin-induced aggregation appears because of a defective von Willebrand activity of the factor VIII molecule.

ISSN:1424-8832    

DOI:10.1159/000214149

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

A method for the evaluation in vitro of platelet-collagen adhesiveness has been developed. This method is based on counting platelets both before and after their contact with an insoluble collagen (IC) suspension. The results are expressed as adhesiveness index (AI). A number of variables which could influence the test has been evaluated and standardized in a way suitable for the routinary use of the technique described.

ISSN:1424-8832    

DOI:10.1159/000214150

出版商:S. Karger AG    

年代:1976

数据来源: Karger

ISSN:1424-8832    

DOI:10.1159/000214151

出版商:S. Karger AG    

年代:1976

数据来源: Karger