bluuebunny/crossref_metadata_2025 huggingface dataset:
Protein C: An Automated Activity Assay
Authors: Ødegaard O.R. , Try K. , Andersson T.R.
Published: April 2009

Protein C in citrated plasma is found to be specifically activated by the snake venom derivative Protac, and the activator is used in a simple, automated assay method. The activation is completed in less than 120 s and an isolation of protein C from its inhibitor before activation is not necessary. The activated protein C is determined with the chromogenic substrate S-2366. Therapeutic concentrations of heparin in the test sample do not influence the result. A strong positive correlation to immunoassay of protein C was found (r= 0.92). Three cases of probable hereditary protein C deficiency belonging to the same family were discovered during the study.
Thrombomodulin Activity Is Found in Tissue Thromboplastin Preparations from Placenta and from Lung but Not from Brain
Authors: Freyssinet Jean-Marie , Gauchy Josiane , Spaethe Reiner , Cazenave Jean-Pierre
Published: April 2009

Substantial thrombomodulin activity could be detected in tissue thromboplastin preparations from placenta or from lung but not from brain. When the amount of these preparations was adjusted to contain 1 unit of tissue factor activity, up to 0.85 units of thrombomodulin activity could be measured, corresponding to the generation of 17 pmol/ml/min of activated protein C when 1.5 μM human protein C was activated by 20 nM human α-thrombin in the presence of 5 mM CaCl2. After treatment by phospholipase C, thrombomodulin activity was reduced in these samples. Addition of mixed brain procoagulant phospholipids partially restored thrombomodulin activity in the phospholipase C-treated samples. These results emphasize the role of phospholipids in the expression of optimal thrombomodulin activity in tissue thromboplastin preparations from placenta or from lung.
Further Investigations on the Significance of a Plasma Coagulation-Accelerating Factor in Glomerular Disease
Authors: Howard Margaret A. , Kincaid-Smith Priscilla S. , Firkin Barry G. , Whitworth Judith A.
Published: April 2009

The prevalence of the coagulation acceleration factor (CAF) in patients with renal disease (predominately glomerulonephritis) has been investigated. The relationship between the activated partial thromboplastin time, F.VIII:C/vWf, prekallikrein, plasminogen and the pathogenesis of glomerulonephritis was also investigated. One hundred and seventeen patients were entered into the study on the basis of admission for renal biopsy. Thirteen percent of the patients showed evidence for CAF and 15 % of patients were found to have reduced levels of plasma prekallikrein; however, no correlation was found between any of the variables measured and the type, activity or progression of glomerular disease in these patients.
Laboratory Monitoring of a Low Molecular Weight Heparin (Enoxaparin) with a New Clotting Test (Heptest)
Authors: Bara L. , Combe-Tamzali S. , Conard J. , Horellou M.H. , Samama M.
Published: April 2009

A new simple clotting test (Heptest) for low molecular weight heparins was compared to anti-Xa determination by an amidolytic assay in volunteers and in patients receiving standard calcium heparin or low molecular weight (LMW) heparin (Enoxaparin) by subcutaneous administration. The results obtained with both methods are in very good agreement. It seems that the Heptest, although influenced by various other clotting parameters, is nevertheless relatively specific for anti-Xa activity. Despite our positive first impression, we object to expressing the results in micrograms of heparin per milliliter or anti-Xa units. Until rigorous standardization is possible, we prefer to express the results as clotting times. Preliminary results warrant a more extensive study in order to assess the clinical relevance of Heptest in patients receiving unfractionated or LMW heparins.
Low Molecular Weight Heparin Fractions as an Alternative Therapy in Heparin-induced Thrombocytopenia
Authors: Gouault-Heilmann M. , Huet Y. , Adnot S. , Contant G. , Bonnet F. , Intrator L. , Payen D. , Levent M.
Published: April 2009

Eight patients with a delayed-onset heparin-induced thrombocytopenia, with thrombotic complications requiring immediate anticoagulation in 7 of them, were given low molecular weight heparin (LMWH) fractions as alternative therapy. This treatment led to normalization of platelet count within 3–5 days in 6 patients with clinical recovery in 5. In 2 patients, thrombocytopenia persisted despite LMWH therapy. In vitro platelet aggregation tests performed in all patients gave evidence of a relationship between the presence (or absence) of a LMWH-dependent platelet-aggregating factor in the patients’ plasma and the persistence (or correction) of the thrombocytopenia with LMWH therapy. Although positive in vitro tests may not necessarily be associated with thrombocytopenia, in vitro testing may prove to be a useful guide before giving LMWH fractions as an alternative therapy in patients with heparin-induced thrombocytopenia requiring immediate anticoagulation.
Influence of Splenectomy on Hemostasis in Agnogenic Myeloid Metaplasia
Authors: Brenner B. , Tavori S. , Tatarsky I.
Published: April 2009

The effect of splenectomy on hemostatic tests was studied in 10 patients with agnogenic myeloid metaplasia. Prolonged partial thromboplastin time and abnormal prothrombin consumption were found before splenectomy and were normalized postoperatively in the majority of patients. Prolonged bleeding time and prothrombin time were normalized in some patients. While platelet counts and fibrinogen levels rose significantly following splenectomy, platelet aggregation remained impaired. Thrombocytosis and increased fibrinogen level after splenectomy in patients with agnogenic myeloid metaplasia can enhance a thromboembolic tendency.
Inhibition of Fibrinolytic System by Liquoid (Polyanetholesulfonate)
Authors: Gilboa Nisan , Ryan Thomas J. , MacColl Robert
Published: April 2009

Liquoid induces microvascular thrombosis and renal cortical necrosis in experimental animals. We hypothesized that thrombosis and renal cortical necrosis may, at least in part, result from the inhibition of the fibrinolytic system by liquoid. Effects of liquoid on plasminogen activation by rat kidney, purified human tissue plasminogen activator (TPA), urokinase, streptokinase, and on the amidolytic activities of TPA, urokinase, and plasmin were studied using chromogenic substrates and clot lysis. Liquoid had a strong inhibitory effect on the fibrinolytic system in vivo and in vitro. The inhibition was most effective at the plasminogen activation level, with activation by streptokinase being most susceptible. The demonstrated stoichiometric binding between liquoid and plasminogen, and to a lesser degree the direct inactivation of plasminogen activators and plasmin, is probably responsible for the reduction of plasminogen activation in circulation and in the kidneys.
Examination of the Utility of the Rat as an Animal Model for Human Anticoagulation
Authors: Smith Lawrence J. , Schaible Keith L. , Fessler Richard G. , Rachlin Jacob R. , Brown Frederick D.
Published: April 2009

The feasibility of employing the rat as an experimental model for investigation of full-dose heparin anticoagulation was assessed. Striking similarities were found to exist between rats and humans regarding (1) baseline-activated partial thromboplastin time (APTT) values, and (2) dosage per kilogram of heparin required to produce an APTT value of 1 ½-3 times normal, the clinical definition of full-dose heparinization. Based upon these similarities, it appears that the rat can effectively serve as an experimental model for investigating the effects of heparin in humans.
Platelet Count Is Positively Correlated with White Cell Count and Red Cell Count
Authors: Milner P.C. , Johl S. , Martin J.F.
Published: April 2009

Platelet count is positively correlated with the white cell count in healthy males aged 20–68 years (p < 0.002) and in healthy medical students of both sexes aged 18–22 years (p < 0.0001). Platelet count is also positively correlated with red cell count in healthy males (p < 0.02). Red cell count is positively correlated with white cell count in the older healthy males (p < 0.02) and in the male medical students (p < 0.003). These findings provide support for the concept of a single hormone-dependent pluripotent stem cell whose effect is seen concomitantly in all circulating blood cells. The white cell count and platelet count correlation is less significant in the males aged 35 or above which may represent the development of pathological mechanisms.
Use of a Centrifugal Analyzer for a Chromogenic Prothrombin Time, a Chromogenic Activated Partial Thromboplastin Time and a Kinetic Fibrinogen Assay in a Routine Hospital Laboratory
Authors: de Metz M. , van Wersch J.W.J.
Published: April 2009

A Cobas Bio® centrifugal analyzer was used in a clinical laboratory for the performance of chromogenic clotting assays. Three commercially available photometric clotting tests – prothrombin time (PT), activated partial thromboplastin time (aPTT) and fibrinogen – were compared with the traditional clotting assays during 3 months. No great discrepancies were found between the traditional assays and the new photometric assays. The chromogenic PT could replace the traditional thrombotest®, PT and Normotest®, because it was sensitive and accurate over a broad range of clotting factor activity. Furthermore the chromogenic PT could be used to discriminate between a decreased clotting activity due to vitamin K deficiency or to a decreased protein synthesis by the liver. A decreased protein synthesis was confirmed by measuring a decrease in the serum cholinesterase activity. The chromogenic aPTT could be used for the assay of heparin concentrations in the therapeutic range and turned out to be more sensitive for deficiencies of factor VIII and factor IX than a traditional clotting aPTT. We conclude that the accuracy and practicability of clotting assays are improved by the new assays without diminishing the clinical value of the results.
Rapid Determination of Five Coagulation Parameters in One Sample with a Centrifugal Analyzer
Authors: Bas B.M. , Costongs G.M.P.J. , Janson P.C.W.
Published: April 2009

Spectrophotometric clotting assays using chromogenic substrates were adapted for use in a routine laboratory batch analyzer. Contrary to another described method the same plasma dilution can be used for each of the different coagulation parameters. Optimal assay conditions were determined. The within- and between-assay variation, the intraindividual variation during 1 day and from month-to-month were determined; the chromogenic assay was compared to a clotting assay. No significant difference (p < 0.01) between manual and automated methods was found.
Study of Different Factor VII Deficiency Variants in Nine Families from Spain
Authors: Pardo A. , Oteyza J.P. , Blanco L. , Correa M.A. , Cesar J. , Steegman J.L. , Tamayo M. , Fernandez I. , Escribano L. , Navarro J.L.
Published: April 2009

Twenty-three patients with congenital factor VII (FVII) deficiency, belonging to 9 kindreds were studied. Immunological variants were classified according to the relationship between FVII coagulant activity (FVIIC) and the level of FVII antigen (FVIIAg), considering 3 previously described groups: VII-, VII+ and VIIR. Activation variants were determined by the reactivity pattern with three different thromboplastins. One patient was classified as VII-, 16 as VII+, and 6 as VIIR. Three patients belonging to the same kindred showed a Padua 2 FVII deficiency, and 1 patient showed a Padua 1 variant. There was no correlation between antigenic or activation variants and severity of bleeding tendency. Classical autosomal recessive mode of inheritance was observed in VII- and VII+ families. Nevertheless, a possible autosomal dominant trait was observed in VII+ kindreds.
Hip Surgery in a Patient with Severe Factor VII Deficiency
Authors: Briët E. , Onvlee G.
Published: April 2009

We describe the clinical history of a 35-year-old woman with severe cross-reacting-material-negative factor VII deficiency. Because of a severe hemophilic arthropathy of the hips, reconstructive surgery was indicated. After advice was obtained from 11 clinical hemostasis experts it was decided to use plasma for factor VII replacement during and after surgery and to use pneumatic boots to prevent thrombosis. Volume overload was treated with plasmapheresis and diuretics. The operation was carried out without abnormal blood loss and the patient recovered without thromboembolic complications. We conclude that continuous infusion of plasma is a suitable way to replace factor VII provided adequate venous access is available for plasmapheresis.
Severity of Coronary Artery Disease and Basal Fibrinolysis
Authors: Small M. , Lowe G.D.O. , Beattie J.M. , Hutton I. , Lorimer A.R. , Forbes C.D.
Published: April 2009

Basal venous blood levels of several components of the fibrinolytic enzyme system (plasminogen activator, plasminogen, fibrin degradation products, α2-antiplasmin, and α2-macroglobulin) were measured in 100 white men with angiographically defined coronary artery disease. The tests of fibrinolysis were not related to the severity of coronary artery disease, as indicated either by the number of vessels involved or by a coronary score system. Fibrinogen levels, however, did show a modest association with the extent of coronary atheroma (r = 0.21, p < 0.05). Triglyceride levels were associated with the inhibitors of fibrinolysis: positively with α2-antiplasmin (r = 0.31, p < 0.005) and negatively with α2-macroglobulin (r = -0.25, p < 0.05). The α2-antiplasmin levels were significantly elevated in patients with hypertriglyceridaemia. Neither smoking nor β-blockade had any effect on the tests of fibrinolysis. This study adds support to the association of plasma fibrinogen with ischaemic heart disease.
Effect of Heparin, Hirudin, and a Synthetic Thrombin Inhibitor on Antithrombin III in Thrombin-Induced Disseminated Intravascular Coagulation in Rats
Authors: Hauptmann J. , Brüggener Ellen , Markwardt F.
Published: April 2009

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.
Antithrombotic Properties of Dermatan Sulphate in a Rat Venous Thrombosis Model
Authors: Maggi Antonio , Abbadini Marzia , Pagella P.G. , Borowska Anna , Pangrazzi Jerta , Donati Maria Benedetta
Published: April 2009

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 heparin.
Factor VII in Subjects at Risk for Thromboembolism: Activation or Increased Synthesis?
Authors: Orlando M. , Leri O. , Macioce G. , Mattia G. , Ferri G.M.
Published: April 2009

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.
Continuous Inhibition of Serotonin-Induced Platelet Aggregation during Chronic Ketanserin Administration to Man Can Be Detected after Plasma pH Control
Authors: Arnout J. , van Russelt M. , Deckmyn H. , Vermylen J.
Published: April 2009

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 period.
Heat-Treated Factor VIII/von Willebrand Factor Concentrate in Platelet-Type von Willebrand’s Disease
Authors: Takahashi Hoyu , Tatewaki Wataru , Nagayama Reizo , Hanano Masaharu , Tamura Makoto , Yamaguchi Toshio , Takizawa Shin-ichiro , Wada Ken , Shibata Akira
Published: April 2009

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 vWD.
Morphometric and Ultrastructural Study of Experimental Venous Thrombosis
Authors: Fumagalli Guido , Angelaccio Erenia , Lombardo Nunzio , Clementi Francesco
Published: April 2009

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.
Platelet Contribution to Cancer Cell Growth and Migration: The Role of Platelet Growth Factors
Authors: Poggi Andreina , Vicenzi Elisa , Cioce Vittoria , Wasteson Åke
Published: April 2009

Blood platelets contain several growth factors and inhibitors. The better known among them are named platelet-derived growth factor (PDGF) and transforming growth factor β (TGFβ), active as modulators of growth of normal mesenchymal and epithelial cells. Cancer cell growth in vitro seems to be independent of the effects of exogenous peptides, but dependent on the cell ability to release autocrine growth factors, similar to PDGF or TGFβ. In addition, platelet-associated growth factors and inhibitors, which are able to induce a fibrotic response in connective tissue cells, might also play a role to modulate the desmoplastic reaction surrounding the tumor.
Platelet Contribution to the Formation of Metastatic Foci: The Role of Cancer Cell-Induced Platelet Activation
Authors: Bastida Eva , Ordinas Antonio
Published: April 2009

Platelets are thought to be involved in the development of blood borne metastasis. Ultrastructural and experimental studies demonstrate that association between tumor cells and platelets with subsequent activation of the coagulation cascade takes place in malignancy. Several hypotheses have been proposed to explain the mechanisms by which tumor cells activate platelets including generation of thrombin, ADP release and involvement of arachidonate metabolism. Perfusion studies with human homologous systems showed that intact tumor cells and tumor cell microvesicles were able to induce platelet thrombogenicity under defined flow conditions. The presence of divalent cations and plasma factors was necessary for the cancer cells to exert their activating capacity. These results suggest a role for platelets in the development of secondary metastasis as well as in the thrombotic events of malignancy.
Expression of Plasminogen Activator as a Marker of Stimulation in Tumor-Associated Macrophages
Authors: Mussoni Luciana , Donati Maria Benedetta
Published: April 2009

Tumor-associated macrophages (TAM) are a peculiar subpopulation of resident phagocytes with activities possibly important at the tumor host interface. Among these activities the production of proteases could obviously influence tumor cell detachment and migration from the primary. We have evaluated the expression of plasminogen activator (PA) in different types of murine tumors with differing immunogenic capacity. In TAM from all tumors studied the expression of PA was markedly greater than that of resident peritoneal macrophages. The fact that PA was similarly enhanced in peritoneal macrophages responding to a standard stimulation (thioglycolate) and in TAM suggests that the expression of PA is part of a more general cellular inflammatory response to injury.
Enhanced Activator Activity of the Mixture of Streptokinase and a Modified Form of Plasminogen (Lys-Plasminogen) in the Presence of Fibrin: Role of Conformational Change of Plasminogen
Authors: Takada Akikazu , Takada Yumiko , Sugawara Yoshiaki
Published: April 2009

Equimolar concentrations of Lys-plasminogen (Lys-PLG) and streptokinase (SK) were mixed with various concentrations of fibrin, fibrinogen, fragment D or E (potentiating agents). The activity of the mixture was measured by the hydrolysis of S-2251. Kinetic analyses indicated that catalytic rate constant (kcat) of the hydrolysis of S-2251 increased in the presence of increasing amounts of potentiating agents. Km did not change in their presence. Effectiveness of the enhancement of the hydrolysis of S-2251 was in the order of fibrin > fibrinogen > E > D. It could be concluded that a complex of SK, Lys-PLG and potentiating agent is a better enzyme, thus activator, than a complex of SK and Lys-PLG. Since Lys-PLG does not change its conformation and its activation rate upon interaction with fibrin, the enhanced activator activity of complex of SK, Lys-PLG and potentiating agent may not be due to the conformational change of Lys-PLG.
Magnetically Driven Thrombolytic Preparation Containing Immobilized Streptokinase-Targeted Transport and Action
Authors: Torchilin V.P. , Papisov M.I. , Orekhova N.M. , Belyaev A.A. , Petrov A.D. , Ragimov S.E.
Published: April 2009

Streptokinase was immobilized on the magnetic carrier at a concentration of 2,000–2,700 IU/ml of preparation. Thrombosis was induced in both canine carotid arteries by means of the vascular wall flap inverting into its lumen. The red, completely occluding thrombus was formed inside the vessel 4–5 h later. A samarium-cobalt magnet was secured externally to one of the arteries. After the clot formation the magnetically immobilized streptokinase was injected intravenously. The preparation concentrated in the region of the magnetic field action caused complete thrombus degradation and normal blood flow restoration; no effect on the clot in the control artery was observed.
Fibrinopeptide A and Bβ 15–42 in Liver Cirrhosis
Authors: Marongiu F. , Mameli G. , Acca M.R. , Mulas G. , Medda A. , Tronci M.B. , Mamusa A.M. , Balestrieri A.
Published: April 2009

In order to detect even minimal fibrinolysis activation in liver cirrhosis, we measured fibrinopeptide Bβ 15–42 (Bβ 15–42), an indicator of plasmin activity in vivo and α2-antiplasmin (α2-AP) in a group of cirrhotic patients. The second goal of this study was to investigate whether an increased fibrinolytic activity is related to a chronic disseminated intravascular coagulation. For this purpose we concomitantly measured fibrinopeptide A (FPA), marker of thrombin activity in vivo. Results show significantly higher levels of Bβ 15–42 in cirrhotic patients than in control (p < 0.01). In patients with high FPA levels we found significantly higher values than in patients with normal FPA (p < 0.01). α2-AP was lower in patients with high FPA levels than in patients with normal FPA (p < 0.05). A significant negative correlation was found between FPA and α2-AP only in patients with high FPA (p < 0.05). There was no relationship between Bβ 15–42 and FPA nor between Bβ 15–42 and α2-AP when all patients were considered. These findings confirm that in liver cirrhosis fibrinolysis activation may occur. The primary pathogenetic role of DIC may be important in this respect. However the lack of correlation between FPA and Bβ 15–42 suggests that other pathogenetic factors may be involved in determining fibrinolysis activation.
Fibrinolytic Activity in Plasma after Gynecological and Urological Surgery
Authors: Aranda A. , Paramo J.A. , Rocha E.
Published: April 2009

Fibrinolytic activity was studied in 51 patients subjected to major surgery (27 urological and 24 gynecological) without prophylaxis. Postoperative deep-vein thrombosis (DVT) was diagnosed by venography in 6 patients (11 %). Blood samples were obtained preoperatively and on days 1, 3 and 7 postoperatively. Reduced fibrinolytic activity, as determined by prolongation of euglobulin lysis time (ELT), decrease in plasminogen activators on fibrin plate and decrease in tissue-type plasminogen activator (t-PA) activity were present postoperatively. Moreover, a marked increase in short duration in fast-acting inhibitor (PA-inhibitor) levels was observed on postoperative day 1 (p < 0.001). Patients with DVT had higher fibrinogen degradation product (FDP) levels on postoperative days 3 and 7 (p < 0.02). Preoperative PA-inhibitor activity was higher (p < 0.02) in those patients who developed postoperative DVT. It is concluded that the decrease in t-PA and the increase in PA-inhibitor may contribute to the reduced postoperative fibrinolytic activity after major surgery. PA-inhibitor may represent a useful predictive marker of postoperative DVT.
Modulation of Endothelial Cell Synthesis of von Willebrand Factor by Mononuclear Cell Products
Authors: Breit Samuel N. , Green Ira
Published: April 2009

Von Willebrand factor (vWf:Ag) is an important product of endothelial cells whose major known functions are coagulation and platelet adhesion. It appears to behave as an acute-phase reactant, levels being elevated in the plasma in a wide variety of inflammatory disorders and in the extravascular compartment in at least some of them. To determine if products of mononuclear cells, activated as part of these disease processes, may directly influence the synthesis and or release of this substance, confluent human umbilical vein endothelial cells were cultured in the presence of supernatants of mononuclear cells undergoing a mixed lymphocyte reaction, and a variety of other purified or recombinant mediators including interleukin-1 (IL-1), interleukin-2, gamma-interferon and prostaglandin E2. The endothelial cell supernatants were then assayed for vWf:Ag levels using a sensitive enzyme-linked immunoassay. The results of this study demonstrate that supernatants of a mixed lymphocyte reaction increase the synthesis and or release of vWf:Ag from endothelial cells in culture by about 100–150%. As these supernatants did not cause any increase in the release of radioisotope from 51Cr-labeled endothelial cells, it appears very unlikely that this increase was simply due to the passive release of this material from dead and dying cells. Increased vWf:Ag release was also demonstrable with purified IL-1 but not with any of the other mediators tested. These results suggest that IL-1 is able to increase the release of vWf:Ag from endothelial cells largely by an increase in synthesis and indicate at least one mechanism whereby mononuclear cells, activated during the course of an inflammatory response, may be able to influence coagulation and platelet function.
Platelet Thromboxane Formation Capacity after Ethanol Withdrawal in Chronic Alcoholics
Authors: Hillbom Matti , Neiman Jack
Published: April 2009

Collagen-, arachidonate- and ADP-stimulated platelet thromboxane B2 (TXB2) formation was studied in platelet-rich plasma (PRP) of 14 alcoholics, 7 of whom had a biopsy-verified alcoholic fatty liver. On admission for detoxication, the alcoholics showed decreased platelet count and aggregability (p < 0.001) as compared to nonalcoholic healthy controls. Platelet TXB2 formation was decreased (p < 0.01), if PRP was stimulated by arachidonate, but not if it was stimulated by ADP or collagen. In contrast, 9–14 days after ethanol withdrawal platelet TXB2 formation had increased to markedly higher levels than those seen in nonalcoholic controls (p < 0.01), if PRP was stimulated by ADP, but not if it was stimulated by arachidonate or collagen. Skin bleeding time was found to be prolonged (p < 0.05) on admission in alcoholics having fatty liver, but it normalized within 2 weeks after ethanol withdrawal. We conclude that the effect of ethanol withdrawal in alcoholics on platelet TXB2 formation is influenced by platelet count, aggregability and the agonist used to induce platelet aggregation.
Effectiveness, Specificity and Safety of Intranasal l-Deamino-8-D-Arginine Vasopressin Treatment of Normal Blood Donors
Authors: Palmer Douglas S. , Harris Allan S. , Tittley Pauline , Rock G.
Published: April 2009

A study of the absorption of 300 µg of l-deamino-8-D-arginine vasopressin (DDAVP) given intranasally to normal blood donors was carried out to determine (a) the correlation between plasma levels of DDAVP and the percent rise of factor VIII procoagulant activity (VIIl:C) and (b) the efficacy, specificity and safety of this treatment in increasing the recovery of factor Vlll:C in donated blood. The maximum drug concentration was highly correlated to the maximum percent rise of Vlll:C (r = 0.858, p < 0.01). A differentiated effect of DDAVP on increases of Vlll:C, VIIl:Ag, vWF:Ag and vWF multimers was observed. A transient rise of fibrinopeptide A from 5 to 16 ng/ml, 30 min post-DDAVP, was not accompanied by changes in fibrinogen levels or generation of detectable factor Xa or thrombin. DDAVP had no effect on the factor XII-dependent pathway of plasminogen activation, or on the donor’s vital signs and hematological parameters. Side effects were minor and of short duration. Intranasal DDAVP treatment of blood donors is considered to be a practical means of improving the recovery of Vlll:C from normal donors.
Physiology of Plasminogen: With Special Reference to Activation and Degradation
Authors: Takada A. , Takada Y.
Published: April 2009

Plasminogen is said to be synthesized in many organs, but the major source of its production is considered to be the liver. The production of plasminogen is observed in fetal life, but its plasma level is low in new born infants, rising rapidly to attain adult levels in about 13 weeks. The plasma levels do not change much with age. Although the fibrinolytic enzyme system is influenced by many factors such as hormones, exercise, emotion, age, sex, nutritional states etc., the plasma levels of plasminogen are relatively stable. In this presentation we would like to discuss three important subjects related to the physiology of plasminogen. The first subject is the activation pathway of the native form of plasminogen (Glu-plg) by various activators in the plasma or clotted plasma. Glu-plg was not easily activated by activators such as urokinase (UK) or tissue plasminogen activator (t-PA), but activated very easily in the presence of fibrin clot. In the presence of purified clot, Glu-plg was partly activated by activators to Glu-plasmin, but also converted to Lys-plg by preformed plasmin, subsequently being activated to plasmin. Glu-plg I (containing two carbohydrate chains) changed conformation more easily upon interaction with fibrin than Glu-plg II (containing one carbohydrate chain) and Glu-plg I was also more easily activated by activators than Glu-plg II. Although Glu-plg was hardly activated by activators in the plasma, Glu-plg was activated easily in the presence of plasma clot. Results of immunoblotting experiments indicated that Glu-plg was mainly activated by activators directly to plasmin, not via Lys-plg in contrast to purified systems. The second subject is the degradation of plasminogen by elastase. Plasminogen may be degraded by proteolytic enzymes such as cathepsin or elastase. The degradation of plasminogen by elastase is shown to give rise to K1 to K3, K4, and mini-pig (containing K5). We have shown that the degradation rate to Glu-plg by elastase increased in the presence of tranexamic acid, indicating that the conformational change of Glu-plg in the presence of tranexamic acid resulted in the exposure of the hydrophobic regions connecting K3, K4 and K5, thus making them accessible to elastase. Consequently, Lys-plg or conformationally altered Glu-plg (possibly bound to fibrin or FDP) is more easily degraded in vivo. The last subject is relationship between plasma plasminogen levels and fibrinolytic activity in various ages. Although plasma plasminogen levels do not change with age, the fibrinolytic activity lowers. We found that t-PA antigen levels increased, PA inhibitor levels decreased, and PA activity decreased with age. These results suggest that the major factor influencing the activity of fibrinolytic system is not plasminogen but other components such as PA, PA inhibitors or inhibitors of plasmin.
Reference Values and Variability of Plasminogen in Healthy Blood Donors and Its Relation to Parameters of the Fibrinolytic System
Authors: Leipnitz G. , Miyashita C. , Heiden M. , Blohn G.v. , Köhler M. , Wenzel E.
Published: April 2009

During a survey of four month’s duration the following parameters were determined in 43 healthy blood donors (22 males, 21 females; mean age 29 years /20 – 49/): plasminogen activity, plasminogen concentration, α2-antiplasmin (α2-AP) activity, α2-AP concentration, tissue type plasminogen activator (t-PA) activity, t-PA concentration, plasminogen activator inhibitor – I (PAI-I) activity, AT III activity, AT III concentration and heparin cofactor II (HC II) activity. Normal values including standard deviation (x ± 2s) were: plasminogen activity: 96.3 % (65.9 – 126.8), plasminogen concentration: 12.2 mg/dl (7.7 – 16.8), α2-APactivity: 99.9 % (83.8 – 116), α2-APconcentration: 108.1% (84.5 -131.8), t-PA activity: 0.85 IU/1 (0.0 – 1.92), t-PA concentration: 10.3 ng/ml (2.5 – 18.1), PAI-I activity: 15.2 AU/ml, AT III activity: 111.4 % (87.8 – 134.9), AT III concentration: 31.6 mg/dl (24.2 – 39.1) and HC II activity: 110.7 % (81.4 – 140.0). Concerning plasminogen values no sex related difference could be stated. Women who were smokers and used oral contraceptives tended to present elevated t-PA activity levels due to a lower activity of PAI-I, although this tendency was not significant. Determining concentration and activity of components in the fibrinolytic system plays an important part in the diagnosis, therapy and prognosis of thrombophilic disorders.
Congenital Abnormal Plasminogen, Frankfurt I, a Cause for Recurrent Venous Thrombosis
Authors: Scharrer I. , Hach-Wunderle V. , Wohl R.C. , Sinio L. , Boreisha I. , Robbins K.C.
Published: April 2009

A new abnormal plasminogen, Frankfurt I, has been identified in the plasma of a 42 year-old male patient who had recurring thromboses, thrombophlebitis and pulmonary embolism since his age of 29. Reduced functional and also slightly reduced antigen plasminogen concentrations were found in both the proposituts and his mother. Plasmin generation rates carried out by Streptokinase and Urokinase were also abnormal. The plasmin generated was very unstable in the absence of stabilizing ligands and/or substrates. Crossed immunoelectrophoresis of the purified Frankfurt I revealed a peak with normal size and shape, but displaced with respect to normal Glu-plasminogen toward the anode. Isoelectric focusing followed by zymography on an agarose-fibrin plate proved this observation but did not indicate a separation of the normal from the abnormal plasminogen molecular species, also, fewer bands were found in the abnormal plasminogen isozyme pattern. Kinetic studies of Frankfurt I Glu-plasminogen and plasmin showed that most of the functional abnormality is related to absence of active sites in half of the molecules.
Characterizing Hereditary and Acquired Defects of Plasminogen
Authors: Hedner U. , Tengborn L.
Published: April 2009

Since plasminogen is the proenzyme of plasmin most acquired defects of plasminogen are associated with situations with an increased fibrinolytic activity. Congenital defects also have been described both such associated with thrombotic disease and such that are not. An increased fibrinolytic activity leading to an acquired plasminogen defect is seen 1) in situations complicated with a free proteolytic activity most often involving both the fibrinolytic and the coagulation systems, 2) as a result of locally increased fibrinolytic activity (angiomas), 3) during thrombolytic therapy using plasminogen activators (SK, UK, tPA). A congenital plasminogen defect characterized by 1) a low protein level as well as one with 2) a normal plasminogen protein level in plasma but a defect activation pattern has been reported. Plasminogen can be determined immunochemically, a method which does not differentiate between functionally active plasminogen/plasmin and complexes between these proteins and inhibitors. Plasminogen activity is measured in a chromogenic method using the chromogenic substrate S2251 (Kabi Diagnostica, Stockholm). In this latter method SK is used as a plasminogen activator and the total plasmin formed is measured amidolytically. Using both the immunochemical and the amidolytical methods it has been possible to identify congenital plasminogen defects characterized by a defective activation of plasminogen into plasmin, a defect that has been associated with thromboembolic disease. Another congenital plasminogen defect seems to be caused by a decreased synthesis of a normal plasminogen molecule. Such a defect may not be associated with thrombotic disease. In situations complicated with an increased fibrinolytic activity, decreased plasminogen levels (in both types of assay) are of diagnostic help. Values down to below 50 % or even lower may be seen. Decreased plasminogen levels are thus seen in acute catastrophies (free proteolytic activity), but also in diseases such as leukaemias, myeloma, liver diseases (is also caused by a defective synthesis in the liver). During thrombolytic therapy with SK or UK an excessive lowering of plasma plasminogen takes place (10 – 20 %). Also during acyl-SK-plasminogen complex treatment, the plasma plasminogen decreases. Following tPA-treatment a more modest plasminogen decrease (∼ 50 %) is seen.
Reduced Fibrinolytic Potential in Patients with Arterial Occlusive Disease (AOD) in Comparison with Normal Subjects
Authors: Hartl D. , Tiso E. , Anderle K. , Philapitsch A. , Anger G.
Published: April 2009

When combining angioplasty and local lysis with urokinase (UK) in treatment of peripheral arterial occlusions we have observed marked differences in the individual patient’s response irrespective of the age of the thrombus. The extensive arteriosclerotic changes revealed by angioghraphy in some of these patients suggest a reduced fibrinolytic potential depending on the underlying disease. In the standard in vitro test system we measured the UK-dependent thrombolysis in blood samples from 10 normal controls at UK concentrations of 150, 200, and 300 IU/ml of whole blood. In comparison we determined the whole blood thrombolysis time (WBTT) of 10 patients with AOD using UK concentrations of 150, 200, and 300 IU/ml of whole blood. The mean WBTT values for normal controls obtained at UK concentrations of 150 IU/ml, 200 IU/ml, and 300 IU/ml, respectively, amounted to 9.5, 5.5, and 3.5 minutes, respectively, while in patients mean values of 20.7, 8.1, and 5.5 minutes, respectively, were found. Studies on plasma samples had shown that the lysis time could be shortened in a dose-dependent manner by addition of lys-plasminogen (LYS-PLASMINOGEN Steam Treated) and to some extent also glu-plasminogen. Since lys-plasminogen gave clearly superior results we tried to improve the lytic potential in terms of a shortening of the WBTT by adding different doses of lys-plasminogen (0.14 – 0.56 CU/ml whole blood) to each patient sample. Although the individual response varied, the addition of lys-plasminogen to the patient samples resulted in a clear dose-dependent improvement of pathologically prolonged lysis times. We conclude from these in vitro findings that the failure of fibrinolytic therapy may in some cases be due to a reduced lytic potential, which may be enhanced by administration of lys-plasminogen, even when the plasminogen level is normal.
Purification of Plasma Protein
Authors: Mannhalter Ch.
Published: April 2009

The purification of coagulation proteins from plasma milieu is a complex and sometimes difficult task. Most clotting factors are present in plasma in trace amounts. They are sensitive to proteolytic degradation and adsorption to surfaces. Thus for most coagulation proteins it was not until the seventies that highly purified preparations were available. Nowadays, most coagulation proteins are isolated from plasma using combinations of ion exchange, molecular sieve and affinity chromatographies. Sometimes, e.g. for Vitamin K dependent factors, specific adsorption properties are utilized. During affinity chromatography, proteins may be bound to specific immobilized receptors, antibodies, substrates, or inhibitors. An example for the latter is the use of bezamidine-Sepharose for the purification of thrombin. Immunoadsorption to immobilized monoclonal antibodies allowed the isolation of highly purified factor VIII:C. For factor XI and prekallikrein the binding of these proteins to the immobilized cofactor high molecular weight kinonogen is utilized for an effective separation of contaminations. Antithrombin III can be isolated by linkage to its cofactor, heparin, on heparin-Sepharose. Using affinity chromatography on lysine-Sepharose it is possible to isolate plasminogen from plasma, serum or urine in a one step procedure with high yield and quality. This, of course, is an ideal situation, where the goal of a purification, namely the separation of a highly purified, biologically active product with high yield can be accomplished in a simple, fast procedure.
Characterization of Commercially Available Plasminogen Preparations in vitro: Purity and Reactivity
Authors: Miyashita C. , Heiden M. , Leipnitz G. , Pindur G. , Wenzel E.
Published: April 2009

Three different commercially available plasminogen preparations (Immuno-, Kabi-, and Behring-plasminogens) were examined regarding purity and reactivity to different activators (high molecular weight [HMW] or low molecular weight [LMW] two-chain urokinase type plasminogen activator [tcu-PA] single chain urokinase type plasminogen activator [scu-PA], tissue type plasminogen activator [t-PA], and streptokinase [SK]). The Immuno-preparation was a Lys-plasminogen, commercially available for therapeutical use, whereas the research reagents from KabiVitrum and Behringwerke were Glu-plasminogen. Activity data provided by the manufacturers correlated well with our findings. Also a good correlation of reactivity to activators measured with a chromogenic substrate and on fibrin plates could be observed. The Immuno-plasminogen showed a minimum contamination with plasmin which has to be taken into consideration for the interpretation for its apparently higher activation by plasminogen activators compared to the plasmin-free plasminogens. Further in vitro and in vivo research has to be performed to find out criteria for a practicable scheme of administration of fibrinolytic agents for therapeutical thrombolysis.