[Evaluation of hemostasis in thrombotic pathology? A critical study apropos of 200 records].
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Biomedical subjects
Publications and source records attributed to C Soria.
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Unfractionated heparin increased the binding of fibrinogen on ADP-treated platelets. The results varied according to both, the platelets of the donor and the kind of heparin preparation used. Beef lung heparin was more active than porcine intestinal mucosa heparin (p less than 0.02). A fraction of low molecular weight low sulfated heparin, did not significantly increase the binding of fibrinogen, except in one case for which the binding of fibrinogen to platelets was largely increased by standard heparin. On the contrary, pentosane polysulfate, a sulfated polysaccharide (of low molecular weight) significantly increased the binding of fibrinogen (p less than 0.01).
The only disorder of coagulation observed after a timber rattlesnake (Crotalus horridus) bite was a total absence of fibrinogen which lasted 64 hours despite hourly administration of cryoprecipitates. The pure defibrination experimentally obtained with this particular species of crotalid snakes underlines the specificity of the coagulation disorder and the impossibility of identifying the coagulopathy induced by venom poisoning without laboratory examination.
The diagnosis and treatment of apparently idiopathic recurrent thromboembolic disease (RTED) still raise difficult problems. However, recent data suggest that abnormalities of coagulation and fibrinolysis factors are important. Hereditary antithrombin III (AT III) deficiency or abnormal AT III, and hereditary protein C deficiency with autosomal dominant transmission have been associated with severe familiar RTED. More recently, we described a dysfibrinogenemia characterized by abnormal fibrin polymerization and abnormal plasminogen binding to the fibrin clot, responsible for familial RTED. Disorders of fibrinolytic activity in RTED are represented, in 70% of the cases, by reduced release or lack of production by endothelial cells of a vascular plasminogen activator. Hereditary plasminogen deficiency or abnormal plasminogen, although rare, are regularly responsible for RTED.
Venous thrombosis occurred frequently in Behçet's disease. In 12 patients with Behçet's disease of whom 6 have had leg venous thrombosis, some parameters of hemostasis or fibrinolysis have been studied. Platelet count, fibrinogen level, factor VIII coagulant activity, factor VIII antigen, plasminogen and antithrombin III level were in the normal range. Fibrinolytic capacity in response to venous occlusion of the arms was the same in patients and in healthy subjects, in the patients, there was no difference in regard to the occurrence of venous thrombosis. These parameters seemed therefore not able to detect the thrombotic tendency in this disease. These results are discussed with the other reports of the literature.
Congenital dysfibrinogenaemia is described in three members of a family presenting with recurrent thrombosis and in two other young members not yet affected. An abnormality in the polymerization of fibrin monomers was noted. In addition, the pathological fibrin clots were found to be less sensitive to degradation by a post venous occlusion euglobulin solution than normal fibrin. After fibrin clot incubation with lys-plasminogen at different concentrations, the biological activity of plasminogen in patient fibrin clot on S 2251 after SK-addition, was less than that observed with normal fibrin. It is speculated that defective in vivo thrombolysis might explain the recurrent thrombosis observed in this family. This finding represents a new concept in understanding thromboembolic diseases.
Platelet GP IIb-IIIa complex is missing or strongly reduced in thrombasthenia type I or II; in parallel the binding of fibrinogen is either nil or strongly reduced after platelet activation and these platelets do not aggregate. In the platelets of the described variant, GP IIb-IIIa level and PLA1 antigen are around 50% of the normal but the fibrinogen sites are either missing or unavailable. The hypothesis is that the patient's platelets lack the specific receptor site for fibrinogen at the GP IIb-IIIa level. However, platelet fibrinogen is normal as is the clot retraction. The study of this variant allows new concepts on platelet aggregation and clot retraction.
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In the presence of an excess of streptokinase (SK) the amidolytic activity of the plasminogen-SK complex on chromogenic substrates is 12% lower in serum than in the corresponding plasma. However, in subjects in whom venous stasis lead to a shortening of the euglobulin lysis time to less than 60 min (high responders), the amidolytic activity of the plasminogen-SK complex in serum was 60% higher than in the corresponding plasma. Attempts to find alterations of the plasminogen molecule itself which would account for the enhanced activity in high responder serum were negative. No free plasmin was present and the plasminogens isolated from plasma and serum before and after venous stasis had the same amidolytic activity as gluplasminogen in the presence of an excess of SK. N-terminal analysis of these four plasminogens revealed in each instance glutamic acid. The enhancement of the amidolytic activity of the SK-plasminogen complex in serum of high responders (potentiator activity) could be reproduced by adding purified tissue plasminogen activator (TA) to native blood before clotting, but not if TA was added to plasma or to prestasis serum. Removal of fibrin degradation products from poststasis serum resulted in the disappearance of potentiator activity. These experiments suggest that fibrin degradation products, generated during clotting in the presence of vascular or tissular plasminogen activator act as a potentiator of the amidolytic activity of the plasminogen SK-complex.
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The gray platelet syndrome is a rare inherited platelet disorder characterized by the absence of alp ha-granules as observed by electron microscopy. Analysis of the glycoprotein composition of the platelets of 2 such patients by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) revealed decreased or absent staining for carbohydrate of several high molecular weight glycoproteins. The major periodic acid Schiff (PAS) staining membrane glycoproteins were normally detected and were normally labeled with 125I during lactoperoxidase-catalyzed iodination. Analysis of the protein composition of gray platelets by single or two-dimensional SDS-PAGE followed by Coomassie blue staining revealed an apparent absence of GP Ig (thrombospondin), markedly reduced platelet fibrinogen and albumin concentrations, and severely reduced levels of 2 low molecular weight polypeptides exhibiting identical rates of migration on SDS-PAGE as platelet factor 4 and beta-thromboglobulin. SDS-PAGE profiles similar to those of the gray platelets were observed with normal human platelets that had undergone the release reaction induced by thrombin. Analysis of gray platelet proteins by crossed immunoelectrophoresis using a rabbit anti-human platelet antibody preparation and rocket immunoelectrophoresis using monospecific antisera confirmed the above findings and showed additional severe deficiencies of factor VIIIR:Ag and cold-insoluble globulin. In contrast, factor XIII (subunit A), a cytoplasmic protein, was normally detected. Our studies provide further evidence that circulating gray platelets specifically lack, or have markedly decreased concentrations of, the alpha-granule proteins.
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We studied the plasma of 18 patients with a functional deficiency of plasma prekallikrein (Fletcher trait). Samples from 13 subjects contained less than 1 per cent of normal levels of prekallikrein antigen recognized by a specific antiserum (cross-reacting-material negative [CRM-]). In the five other subjects, however, nonfunctional material immunologically indistinguishable from normal prekallikrein was detected by radioimmunoassays at concentrations of 13 to 30 per cent (CRM+ variant). None of the plasma samples contained detectable circulating anticoagulants against prekallikrein. On immunodiffusion against antiserum to kallikrein, each of the five CRM+ samples formed a single precipitin line of complete identity with normal plasma or purified prekallikrein. On immunoelectrophoresis, the precipitin line had the same mobility as that for normal prekallikrein. These studies demonstrate the molecular heterogeneity of human prekallikrein deficiency and show that persons with the CRM+ variant have a nonfunctional form of prekallikrein in their plasma.
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A new case of congenital dysfibrinogenaemia was found in 2 members of the same family. The anomaly was characterized by an abnormal polymerization of fibrin monomers, whereas the release of fibrinopeptides by thrombin and fibrin stabilization by F XIII were normal. Investigation of the fibrinogen molecule did not lead to localizing the structural abnormality.