摘要:

The revised ratio method which is recommended for standardization of the one-stage prothrombin time, presumes that identical regression lines exist between clotting times of abnormal and normal plasma. A modification is proposed which corrects for possible deviation of the mean clotting time of normal plasma from the regression line between clotting times of abnormal plasma. The modified revised ratio method is theoretically preferable and does not need the restrictions in calibration which are recommended for the revised ratio method.

ISSN:1424-8832    

DOI:10.1159/000215763

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

The effect of heparin, hirudin, and a synthetic thrombin inhibitor on antithrombin III, fibrinogen and platelets was studied in a rat model of disseminated intravascular coagulation (DIC) induced by thrombin infusion. Antithrombin III is consumed during thrombin infusion to a limited degree. Simultaneous administration of exogenous thrombin inhibitors ameliorates the consumption of fibrinogen and platelets. At high thrombin doses, tolerated only during additional administration of thrombin inhibitors, heparin leads to increased consumption of antithrombin III, whereas hirudin and the synthetic inhibitor do not. In every case, the thrombin effect on fibrinogen and platelets is inhibited.

ISSN:1424-8832    

DOI:10.1159/000215764

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

It has been suggested that glycosaminoglycans (GAG) such as heparan sulphate (HS), dermatan sulphate (DS), chondroitin-4-sulphate and chondroitin-6-sulphate contribute to the nonthrombogenic properties of the vascular wall [1]. We have investigated the potential role of DS and HS as antithrombotic agents in an experimental model of stasis-induced venous thrombosis in rats. We utilized a range of doses of both DS and HS (0.25–4 mg/kg BW) to test both their antithrombotic activity and potential bleeding effects. The results were evaluated with reference to an unfractionated heparin (0.5–2 mg/kg BW). We report that the antithrombotic activity of DS is not related to its anticoagulant activity as measured by the activated partial thromboplastin time (APTT), thrombin time (TT) and anti-Xa tests. The dose of DS which was able to inhibit thrombus formation by 70% did not prolong the bleeding time measured using two techniques (template and tail transection); in contrast, with HS a prolongation of both times could clearly be seen. On the other hand, standard unfractionated heparin, at a dose which is equipotent to that of DS in preventing thrombus formation, significantly prolonged the bleeding time. These results suggest that DS may be a useful antithrombotic agent with a lower haemorrhagic effect than heparin, unlike HS which expresses a haemorrhagic risk similar to hepa

ISSN:1424-8832    

DOI:10.1159/000215765

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

58 patients with clinically localised breast carcinoma, treated by either mastectomy alone or lumpectomy plus local radiotherapy, have now been followed for up to 51 months (median 12 months). 21 of the 58 patients (36.2%) had a persistently elevated or rising fibrinopeptide A level after surgery and 11 of these patients (52%) to date have subsequently developed recurrent breast carcinoma up to 27 months after the fibrinopeptide A level became elevated (median 6 months). Conversely, only 2 (5.4%) of the 37 patients with persistently normal post-operative fibrinopeptide A levels have developed recurrent disease. Elevated fibrinopeptide A levels appear to be a marker of persistent tumour activity and precede clinical recurrence in certain patients with breast carcinoma, but normal values do not exclude recurrent or residual disease.

ISSN:1424-8832    

DOI:10.1159/000215766

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

In this study the preliminary results obtained by investigating factor VII:antigen and activity in 38 subjects with arterial disease of the extremities are reported. The antigen determination (VIl:Ag) was performed by using an inhibitor neutralization assay; factor VII activity (VIl:C) was determined by one-stage assay with human factor VII artificially depleted plasma. All the patients showed increased levels of VIl:C and VIl·Ag compared to the reference population (p < 0.001). There is a significant correlation between VIl:C and VIl:Ag (r = 0.47), but the ratio VIl:C/VIl:Ag is slightly increased. Our results confirm that elevated levels of factor VII are present in patients with tendency to thrombosis

ISSN:1424-8832    

DOI:10.1159/000215767

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Ketanserin is a well-known serotonin S2 receptor antagonist but its capacity to inhibit serotonin-induced aggregation ex vivo during chronic administration has been a matter of debate. In vitro evidence is presented that the inhibitory capacity of ketanserin is lowered by increasing plasma pH. Since the pH of plasma kept at the open air increases with time, we studied the effect of chronic administered ketanserin on serotonin-induced platelet aggregation in plasma kept at a lowered pH of 7.70, by replacing the air with 95% O2–5% CO2. Using this slightly modified technique, we could, in contrast to our previous studies, observe a complete inhibition of the serotonin-induced aggregation throughout the ketanserin treatment perio

ISSN:1424-8832    

DOI:10.1159/000215768

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Microscopic particles of microfibrillar collagen hemostat (MCH) have been shown to pass through a 40-μm blood transfusion filter. This study indicates that MCH passing through the filter retains a significant portion of its ability to aggregate platelets in vitro and the aggregating ability is dose related. The extent of platelet aggregation in the presence of the MCH filtrate or an ADP standard was measured photometrically and log dose-response curves constructed from the data. An ED50 of 3.6 μg protein/ml platelet-rich plasma (PRP) was calculated at a protein concentration of 7.6 mg/ml in the MCH filtrate and an ED50 of 5.9 μg protein/ml PRP at 12 mg/ml protein in the MCH filtrate. The platelet aggregating ability of the MCH filtrates corresponded to 18.8 and 39.6% of the maximum response produced by adenosine-5’-diphosphate. These findings support the view that blood contaminated with MCH should not be returned to a patient’s circu

ISSN:1424-8832    

DOI:10.1159/000215769

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Cryoprecipitate has proved to correct the hemostatic defects in von Willebrand’s disease (vWD) and platelet-type vWD. However, recent studies have revealed that transmission of the AIDS retrovirus (HIV) occurs through exposure to blood products including cryoprecipitate. Treatment with heat-treated factor VlII/von Willebrand factor (vWf) concentrates may have certain advantages over treatment with nonheated products, if these preparations are efficacious in these disorders. We found that a commercially available factor VIII/vWf concentrate, Haemate P, contained the high-molecular-weight multimers of vWf and had a ratio of ristocetin cofactor (RCof) to vWf antigen (vWf: Ag) close to unity. In addition, its capacity to directly induce aggregation of platelet-type vWD platelets in vitro was similar to that for cryoprecipitate. When infused into a patient with platelet-type vWD, Haemate P shortened the prolonged bleeding time and caused spontaneous platelet aggregation in vitro with a mild diminution of platelet count. These results indicate that some of the heat-treated factor VIII/vWf concentrates may provide a safer, yet still effective, treatment for platelet-type vW

ISSN:1424-8832    

DOI:10.1159/000215770

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Defibrotide is a profibrinolytic agent which has potent stimulatory effects on vascular prostacyclin (PGI2) production and secretion. We have studied the effects of this substance on the morphological organization of venous thrombi by combining ultrastructural evaluation with histometric analysis. Thrombosis was induced by inserting a collagen-coated thread into the femoral vein of rabbits 2 h before sacrifice. The results show that Defibrotide is highly effective in reducing the size of the thrombus. This is due to combined profibrinolytic action and interference with platelet and leukocyte adhesion as indicated by results showing that: (i) large deposits of fibrin-like material are smaller and less abundant; (ii) platelet aggregates are smaller, and (iii) the density of leukocytes in thrombus is strongly decreased. Polymorphism is prominent in platelets which are indistinguishable from control suggesting that the primary site of action of Defibrotide is on adhesion. The inhibitory effect on leukocyte participation to the thrombotic process is probably due to PGI2 release and may be of relevance on maturation and aging of the thrombus.

ISSN:1424-8832    

DOI:10.1159/000215771

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Plasma levels of Bβ15-42 peptide and fibrinopeptide A (FPA) were measured as indicators of plasmin-mediated fibrin(ogen)olysis and thrombin activity of fibrinogen in 34 middle-aged men, at rest and following a standard exercise test. In the group as a whole no significant changes in Bβ15-42 or FPA were noted after exercise. When the group was subdivided into men with (n = 20) and without (controls n = 14) coronary heart disease, exercise-stimulated thrombin and plasmin generation was found only in the control group who exercised for a significantly longer duration. The rise in Bβ15-42 was related to both the intensity and duration of exercise. Similar increases in plasma fibrinolytic activity (fibrin plate) occurred in both groups and no other differences in the components of the fibrinolytic system (plasminogen, α2-antiplasmin, fibrin degradation product) were noted either after exercise or between the groups. Exercise in normal middle-aged men is associated with modest thrombin and plasmin activat

ISSN:1424-8832    

DOI:10.1159/000215772

出版商:S. Karger AG    

年代:1987

数据来源: Karger