摘要:

In contrast to earlier assays, the prothrombin determination described here uses a two-step reaction: first, prothrombin is activated with human factor Xa, phospholipids, Ca++ and factor V; second, the amount of activated prothrombin is assayed by the proteolysis of added fibrinogen. The assay is dependent only on prothrombin, and independent of other components of thrombin generation. Carboxy- and decarboxyprothrombin can be differentiated by means of using Echis carinatus venom instead of factor Xa as activator. The micro-coagulation assay is compared with a conventional one-stage coagulation test, with a prothrombin determination using chromogenic substrate and immunologically by Laurell electrophoresis.

ISSN:1424-8832    

DOI:10.1159/000214697

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

A sensitive solid phase enzyme immunoassay (EIA) was developed for the measurement of factor IX antigen (IX:AG), using rabbit antihuman factor IX antiserum and β-D-galactosidase, which enabled us to detect IX:AG as low as 10-4 U/ml. 37 patients with severe hemophilia B have been investigated by EIA, inhibitor neutralization assay and bovine brain prothrombin time. They could be divided into four genetic variants. 25% had normal levels of IX:AG but decreased levels of factor IX clotting activity. On crossed immunoelectrophoresis of the hemophilia B+ and hemophilia BM, we could not find abnormalities in electrophoretic mobilities compared to normal subjects in the presence of 1 mM Ca++ lactate

ISSN:1424-8832    

DOI:10.1159/000214698

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Platelets are well suited to X-ray microanalysis as there is no need for chemical fixation or sectioning, and the concentrations of calcium and phosphorus are above 10-3. The principles of the technique, the methods of specimen preparation, instrumental conditions during analysis and ways of quantitation are described. This is followed by a review of published reports and a brief summary of the author’s own work in the fiel

ISSN:1424-8832    

DOI:10.1159/000214699

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The specificity, distribution and rate of uptake of radiolabelled 125I-Lys-plasminogen by in vitro thrombi was investigated. 125I-Lys-plasminogen was added to whole blood perfusion mediums containing preformed thrombi and to whole blood prior to thrombus formation. Uptake was assessed by means of radioisotopic analysis and autoradiography. The plasminogen was taken up by thrombi during and after their formation. The largest percentage was in the fibrin component. ε-Aminocaproic acid-blocking experiments confirmed the specificity of plasminogen binding to fibrin. Autoradiography of the thrombi revealed plasminogen in the RBC-fibrin part and in platelet-fibrin aggregates. Plasminogen uptake and penetration into preformed thrombi were found to increase as a function of time. However, formation of thrombi from plasminogen-enriched blood was a more effective means for increasing the plasminogen content of thrombi than perfusion of preformed thrombi in a plasminogen-enriched medium, over the time period studied

ISSN:1424-8832    

DOI:10.1159/000214700

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The effect of normal and nonenzymatically glycosylated rat type I acid-soluble collagen on normal human platelets was investigated. Glycosylated collagen was obtained either after in vitro incubation with glucose or from rats made diabetic by streptozotocin. The amount of nonenzymatically bound glucose was as follows: normal 2.3, diabetic 7.6 and in vitro glycosylated collagen 9.0 nmol/mg. When investigated under conditions leading to identical diameters and molecular packings for all the samples, the aggregation potency was markedly stronger for diabetic and glycosylated collagens than for normal ones. These results show the potential role of this posttranslational modification of collagen which can be considered as a risk factor in the thrombotic pathogeny of diabetes.

ISSN:1424-8832    

DOI:10.1159/000214701

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Acetylsalicylic acid (ASA), given i.v. to male rats 10 min before electrical injury to the carotid artery, was found to reduce rate and extent of thrombosis at 3.3 and 10.0 mg/kg but not at 1.7, 20 or 100 mg/kg, indicating a narrow, low-dose window for antithrombotic effect. ASA was more effective in rats in which body temperature was allowed to fall > 0.5 °C but protection was lost if injury was delayed 15 min or more after ASA administration. Serum salicylate studies did not support the view that loss of protection was due to competition between salicylate and ASA for cyclooxygenase-binding sites. ASA was also protective at 200 mg/kg i.v., possibly through non-specific toxic effects

ISSN:1424-8832    

DOI:10.1159/000214702

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

A modification of the original thiobarbituric acid (TBA) method for malondialdehyde (MDA) assay is described. The improvement is essentially based on the clearing effect of KClO4 that makes measurements more simple and sensitive. MDA values obtained in normal subjects were almost eightfold higher than those obtainable with Stuart’s original assay method, so that after cyclooxygenase block it was possible to assess platelet regeneration time even in thrombocytopenic patients with at least 60,000 platelets/µl and MDA production early after aspirin intake. To challenge this modification, platelet regeneration time was studied in normal subjects as well as in thrombocytopenic patients, either hypoplastic or idiopathic, and in hypoxemic patients with increased platelet consumption. The initial disappearance kinetics of platelet MDA and thromboxane B2 production after aspirin suggests that TBA-reactive material is synthesized through the lipoxygenase pathway. The reversible block determined by acetylsalicylic acid and salicylate on hydroperoxieicosatetraenoic acid peroxidase can be responsible for the initial increase of this TBA-reactive materi

ISSN:1424-8832    

DOI:10.1159/000214703

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

A method to induce microthrombi in small mesenteric arteries (ø 15–25 μm) has been developed to study platelet reactions and to investigate antithrombotic drugs. A high power water immersion interference contrast system, based on a Leitz Orthoplan microscope, was used. In Nembutal-anesthetized male Wistar rats and in fawn hooded bleeder rats, vascular lesions were produced with a Hadron-512-Ruby-bio-laser or with a Coherent CR-2 supergraphite ion laser (Argon laser). The ruby laser produced intravascular precipitates consisting of proteins and erythrocytes which usually stuck to the vessel wall and on which platelets immediately adhered, transformed with pseudopode formation and formed loose aggregates. The Argon laser induced vascular damage, usually without intravascular heat precipitates which also led to platelet adhesion, transformation and aggregation. Fibrin threads rarely formed in the early platelet thrombi. Thrombus formation was significantly reduced in this model by dipyridamole (10 mg/kg orally), by Ditazole (50 mg/kg orally), heparin (100 IU/kg i.v.), Molsidomine (50 mg/kg orally), Nafazatrom (Bay G 6575, 10 mg/kg i.v. and orally), Ticlopidine (100 and 200 mg/kg orally) and Tioxaprofen (EMD 26644, 10 mg/kg orally). Thrombus formation was also significantly reduced in fawn hooded bleeder r

ISSN:1424-8832    

DOI:10.1159/000214704

出版商:S. Karger AG    

年代:1983

数据来源: Karger

ISSN:1424-8832    

DOI:10.1159/000214705

出版商:S. Karger AG    

年代:1983

数据来源: Karger

ISSN:1424-8832    

DOI:10.1159/000214832

出版商:S. Karger AG    

年代:1983

数据来源: Karger