bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects Of Fibrin, Fibrinogen And Fibrin(-Ogen) Degradation Products On The Growth Of Aortic Smooth Muscle Cells In Culture
Authors: Tanaka K , Ishida T , Watanabe K 
Published: July 2018

Importance of smooth muscle cell proliferation has been emphasized as a key event in atherogenesis. A number of factors have been shown to stimulate cell proliferation in vitro. These include platelet, lipoprotein, insulin and so on. We studied the effects of fibrin, fibrinogen and fibrinogen degradation products on the growth of aortic smooth muscle cells in culture. Smooth muscle cells in the 7th-15th subculture were grown from the explants of the media of rabbit thoracic aortas.Growth behavior of the cultured smooth muscle cells in response to fibrin clot was observed with phase-contrast microscope. Fibrin clot stimulated the cell proliferation during the period of 24 hours cultivation.Effects of fibrin,fibrinogen and fibrinogen degradation products on the incorporation of [3H] thymidine by the cultured smooth muscle cells were studied in replicate culture method. Both fibrin and fibrinogen stimulated the incorporation of [3H] thymidine during the period of 24 hours cultivation. But they inhibited the incorporation after 48 hours, and smooth muscle cells were degenerated and detached from the tissue culture dish. Fibrinogen degradation products inhibited the incorporation of [3H] thymidine by smooth muscle cells.The cultured smooth muscle cells showed fibrinolytic activity by Todd’s fibrinolysis autography.These results suggest that both fibrin and fibrinogen have the stimulatory effect, while fibrinogen degradation products have the inhibitory effect on the proliferation of smooth muscle cells, and that fibrinolytic activity of arterial wall might play a role in smooth muscle cell proliferation that leads to the development of atherosclerotic lesions.
The Use Of Proteolytic Probes To Identify Platelet Membrane Receptors
Authors: Bemdt Michael C , Phillips David R 
Published: July 2018

One approach to the study of structure-function relationships with plasma membrane glycoproteins is to use proteases whose substrate specificity permit cleavage of only a single glycoprotein. We have employed this approach using two proteases, human platelet calcium-dependent protease and thrombin, as probes to investigate the identity of the platelet membrane von Willebrand Factor and thrombin receptors, respectively. Extensively purified calcium-dependent protease added exogenously to washed human platelets catalyzed the hydrolysis of only one membrane glycoprotein, glycoprotein Ib. The hydrolytic product of glycoprotein Ib as determined by immunoprecipitation and other criteria was glycocalicin. Correlation of the level of intact glycoprotein Ib with maximal agglutination rate to and binding of Factor VIII/von Willebrand Factor confirms previous observations consistent with glycoprotein Ib being the von Willebrand Factor receptor on human platelets.Since the catalytic integrity of thrombin is requisite for platelet response, we have sought to identify a thrombin substrate(s) on the platelet membrane surface. Glycoprotein V was the sole apparent thrombin substrate evident on O’Farrell gels of periodate-labeled control and thrombin-treated washed human platelets. We have recently purified this glycoprotein to homogeneity and confirmed it to be a thrombin substrate (Bemdt and Phillips (1981) J. Biol. Chem., 256: 59-65). Several lines of evidence will be discussed that are consistent with glycoprotein V being the probable functional thrombin receptor on human platelets.
A Variant of Factor X That Is Defective Only In Extrinsic Coagulation
Authors: Bertina R M , Alderkamp G J H , de Nooy E 
Published: July 2018

Screening - prior to liver biopsy - of the blood of a 48- year-old patient with a negative anamnesis for bleeding complications, revealed a strongly prolonged prothrombin time (PT), while the APTT was normal. The PT prolongation was not the consequence of an antithromboplastin, vitamin K deficiency, oral anticoagulation or factor VII deficiency (FVII 0.5 U/ml). A more detailed analysis demonstrated the presence of an abnormal factor X molecule with the following properties: coagulation assays: 0.016 U/ml (thromboplastin), 0.43 U/ml (RVV/cephalin), 0.44 U/ml (kaolin/cephalin); spectrophoto- metric assay (RVV-X/S2337), 0.47 U/ml; immunological assay (Laurell), 0.50 U/ml. The low reactivity towards the extrinsic activator depends on the thromboplastin used: human brain, 0.016 U/ml; bovin brain, 0.11 U/ml.The FX-variant has a normal electrophoretic mobility (crossed immunoelectrophoresis) and can be absorbed from plasma by Al(OH)3 The variant has been purified from the patients plasma using affinity chromatography on anti-factor X Sepharose, followed by DEAE-Sephadex gradient elution.The isolated variant shows the same low reactivity towards extrinsic activation. Comparison with isolated normal FX showed that it has the same molecular weight (NR 70,000; R 51,000 and 19,000). The heavy chain stains positive with the Schiff’s reagent. Variant FX can be activated by RVV-X under formation of αXa (51,000), which in the presence of phospholipid is degraded to αβXa (48,000) and αγX (35,000).Analysis of the kinetics of activation of normal and abnormal FX by FIXa, FIXa plus FVIII, or RVV-X revealed no essential differences. Only the activation by FVII-thrombo- plastin showed to be abnormal.The complete absence of bleeding complications in this particular patient, might indicate that in vivo the extrinsic activation of factor X is only of minor importance.
A Novel Method For The Direct Determination Of Platelet-Associated IgG (PAIgG) Employing Rocket Immunoelectrophoresis (Laurell)
Authors: Kunicki T J , Kristopeit S M , Aster R H 
Published: July 2018

The diagnosis and management of immune thrombocytopenia requires an effective method for the quantitation of platelet- associated IgG (PAIgG). Although several methods have been recently devised for this purpose, the search continues for a method which will prove to be accurate and reproducible, and yet simple enough to be utilized by the general clinical hemostasis laboratory. We now describe the development of an assay for PAIgG which we believe satisfies these criteria.Human platelets were isolated by differential centrifugation, washed five times in Tris-HCl pH 7.4 or phosphate buffered saline pH 7.4, both containing 5mM EDTA, and disrupted in 0.1M sodium acetate buffer pH 5.0 containing 1% (v/v) Triton X-100. Rabbit antibody specific for γ chains of human IgG (purified IgG fraction from DAKO) was carbamylated such that its isoelectric point was decreased to roughly 5.0. Total PAIgG was measured by electrophoresis at pH 5.0 of Triton X-100 disrupted washed platelets against the carbamylated rabbit anti-human IgG (γ) in 1% agarose gels containing 0.5% Triton X-100.The mean total PAIgG for 8 normals, was 5.7 fg/platelet (range 4.9 to 7.0). This technique is applicable to the quantitation of alloantibodies bound to normal platelets (indirect assay) as well as the quantitation of PAIgG on platelets of individuals with immune thrombocytopenic states, such as ITP.
Factors Affecting Thrombus Formation On Surfaces
Authors: Schultz J S , Lindenauer S M , Penner J 
Published: July 2018

An ex-vivo test device consisting of a flow-through cylinder with a rotatable central rod has been developed for evaluating thrombus formation on surfaces. The rod can be coated with polymers, or segments of blood vessels can be placed on the rod. Blood access to the device is obtained by means of a A-V shunt, using dogs as the test animal. Measurement of platelet, fibrinogen, and red cell content characterizes thrombus composition on the rod and provides several indicies of the coagulation systems involved in thrombus development.Tests of more than a dozen biomaterials showed that thrombus amount and composition on surfaces differ many fold under similar flow conditions. Increases in shear from 100 sec-l to 200 sec-l on the rod surface, by increasing the rotation rate of the rod, resulted in virtually complete reduction of rbc attachment, corresponding to a 75% inhibition of fibrinogen deposition while platelet attachment was only reduced by 50%. This demonstrates that shear has a differential effect on the various components of the clotting system.The use of systemic drugs like aspirin and heparin showed that the effects on thrombus formation are quite different for materials with various degrees of thrombo-genicity. Also it was demonstrated that when the same polymer material was cast from two different solvents to obtain variations in surface morphology the thrombogenicity was quite different.A direct comparison of the thrombogenicity of biomaterials and vascular endothelium is possible by placing an everted piece of vein on the coated rod.Tests showed that silastic and vein endothelium were similar with respect to platelet and frbrinogen deposition. This ex-vivo procedure provides an opportunity to assess the antithrombogenic effect of drugs applied directly to the surface of the excised vessel segment.
The Lack Of Relationship Between Anti-Xa Activity And Antithrombotic Activity Of Low Molecular Weight Heparin
Authors: Ockelford P A , Carter C J , Hirsh J 
Published: July 2018

The effectiveness of low dose heparin in the prevention of venous thrombosis and pulmonary embolism has been attributed to its enhancement of plasma anti-Xa activity. Low molecular weight (MW) heparin fractions have a relatively high anti-Xa activity, both in vitro and ex vivo, and it has been assumed that this high anti-Xa activity correlates with antithrombotic activity.We have compared the antithrombotic effect of a very low MW heparin fraction (mean MW 3,000) with standard heparin (mean MW 15,000) using a rabbit prophylaxis model and thromboplastin as the thrombogenic stimulus. The antithrombotic effect of these heparins was related to ex vivo anti-Xa heparin activity. Both heparins showed a dose-dependent antithrombotic effect, enabling the relative antithrombotic and anti-Xa activities to be compared over a dosage range. Even when the ex vivo anti-Xa activity achieved with the low MW heparin was significantly greater than for the standard heparin (0.41 and 0.16 anti-Xa units per ml; p < 0.01), significantly less inhibition of thrombosis was observed with the low MW heparin fraction (24% and 88%; p < 0.02). For an equivalent antithrombotic effect (50% inhibition of thrombosis) an ex vivo anti-Xa activity in excess of five fold was required in the low MW heparin treated animals. These findings are in contrast with our previous experience using a low MW fraction (mean MW 4,600) and suggest that the relationship between anti-Xa activity and antithrombotic effect may be MW dependent.
Association Between Plasma Concentration Of Factor VIII Related Antigen, ABO Blood Type And Lewis Blood Type
Authors: Orstavik K H , Magnus P 
Published: July 2018

Individuals with blood type 0 have a lower plasma concentration of factor VIII than individuals with blood type A. Since the Lewis blood type system and the ABO blood type system are related, we looked for a possible association between the plasma concentration of factor VIII and Lewis blood type.Plasma concentration of factor VIII related antigen (FVIIIR:Ag) was determined by the Laurell electroimmunoassay in 333 individuals. These individuals were identical and fraternal twins who had been bled as part of a twin study on coagulation factors. The association between factor VIII and ABO blood type was confirmed since a significantly lower concentration of FVIIIR:Ag was found in individuals with blood type 0 (77%) than in individuals with blood type A (106%). Lewis blood type had no significant effect on the concentration of FVIIIR:Ag when the whole material was examined. Within individuals with blood type 0, a much lower concentration of FVIIIR:Ag was found in individuals with Lewis blood type Le(a-b-) (52%) compared to individuals with Lewis blood type Le(a-b+) (80%) or Le(a+b-) (88%).The possibility that individuals with blood type 0 and no Lewis antigens have a low plasma concentration of factor VIII may have implications for the detection of carriers of hemophilia A.
Improvement Of Shortened Platelet Survival Half-Life From The Early To The Late Phase Of Myocardial Infarction
Authors: Chesebro J H , Fuster V , Byrne J 
Published: July 2018

The incidence of reinfarction, death and systemic thromboembolism is greatest in the first 2 months after acute myocardial infarction and decreases with time after infarction. Reasons for this are unknown, but increased platelet vascular wall interaction may be a contributing factor. Thirteen patients, mean age 53 years, had a platelet survival determination (platelet half-life calculated by least square analysis) within 1 month (mo) after acute, uncomplicated myocardial infarction (10 transmural, 3 subendocardial); a platelet survival study was repeated 3-8 mo (average 4 mo) later. All patients were on oral anticoagulants and during the time of observation none of the patients had any clinical thromboembolic events.Ten of the 13 patients had a shortened (<92 hours) platelet survival half-life of 75 hours (avg) within 1 mo after myocardial infarction which increased significantly (P<.01) to 94 hours (avg) four mo (avg) later. Ten control patients with angiographically proven coronary artery disease, stable angina pectoris, and a shortened platelet survival of 85 hours (avg) had a repeat platelet survival 6 mo later that was not significantly changed (mean variability 5%).The shortened platelet survival that improves with time after myocardial infarction is compatible with the increased incidence of reinfarction, death and thromboembolism early after myocardial infarction. Whether the increased platelet consumption reflects platelet deposition in the coronary vessels or in the left ventricle (as a mural thrombus) is at present under investigation with imaging of III-Indium-labeled platelets.
A Plasma Fibrinogen Fraction With High Sialic Acid Content And Eecngated γ-Chains
Authors: Kuyas C , Haeberli A , Straub P W 
Published: July 2018

Having recently been able to separate Bβ- and γ-chains of human fibrinogen heterogeneous with respect to sialic acid, we were faced with the question whether a carbohydrate heterogeneity might be present in the original native fibrinoge.Using DEAE 52 cellulose and stepwise elution with phosphate buffer human fibrinogen from pooled or single donor plasma could indeed be separated into 3 populations with different sialic acid content. The most acidic fraction contained 30% more sialic acid (8 moles) than the original fibrinogen (6 moles). After reduction the 3 fibrinogen fractions were analyzed by two-dimensional electrophoresis. The first fraction (15%) contained partly degraded Aα-chains and a pattern of Bβ and γ-chains similar to the one described for the main fraction. The latter (70%) consisted of intact Act-chains, two main Bβ- and two main γ-chains and one additional minor band for each chain, all with the previously described carbohydrate heterogeneity.The third, most acidic fibrinogen fraction (15%) revealed an unusual γ-chain pattern. In addition to the two normal chains, two γ-chains with higher mol. wt. and more acidic IEP were found. The Aα- and Bβ-chains did not differ from those of the original fibrinogen. Again a heterogeneity with respect to sialic acid was visible both in the Bβ- and the normal as wsll as the elongated γ-chains. Desialylation of the elongated γ-chains resulted in only partial normalisation of the IEP.The binding of EDTA and citrate shows a strong ^-dependence suggesting a (partly) ionogenic binding between charged areas on the fibrinogen molecule and charged groups on EDTA or citrateIt has thus been possible to attribute the recently described elongated γ-chain variants to a particular sialic acid rich subfraction of normal human fibrinogen and therefore to conclude that the observed fibrinogen heterogeneity is at least to a considerable extent of inter- rather than intramolecular nature.
Comparative Effects Of Tissular Urokinase And Urinary Urokinase In The Treatment Of 30 Patients With Pulmonary Embolism And Deep Venous Thrombosis
Authors: Lorient-Roudaut M F , Vergnes C , Bonnet J , Boisseau M R , Bricaud H 
Published: July 2018

Two types of Urokinase are actually available for the clinical use : tissular urokinase (tUK), isolated from cell culture and urinary urokinase (uUK), partially purified from human urine. Their clinical and biological effects have to be compared.In this study 30 patients with acute pulmonary embolism and/or deep venous thrombosis were treated, using tUK or uUK, 4500 units/kg, during 12 hours.In the clinical field pulmonary angiographies, scintigrams, and phlebographies were obtained before and after the treatment. The biological study was first established on serial determination of fibrinogen, platelets, Quick Time, FDP using two methods and euglo- biiin lysis time. At the end of the treatment plasmatic samples of each patients were studied by immunoprecipitations followed by polyacrylamid gel electrophoresis, in the view of evaluation of the D dimer E complex. Two methods were used (LANE D.A. and al., 1977and WHITAKER A.N. and al, 1980).The results showed a quick similar improvement of the clinical situation. In return tUK appeared to be more effective on the biological point of view. Significant differences were found in : decrease of fibrinogen, increase of FDP and the presence of D dimer fragments. The better action of tUK, especially on the fibrin depositions, is so far unexplained.
A Monoclonal Antibody To Factor IX
Authors: Goodall A H , Janossy G , Kemble G , O’Brien D P , Rawlings E , Rotblat F , Russell G , Tuddenham E G D 
Published: July 2018

We describe a mouse monoclonal antibody with high affinity for a functional site on coagulation factor IX.Mice were hyperimmunised to factor IX by repeated intraperitoneal injections of between 15 and 20 µg of purified factor IX in complete Freunds adjuvant, over a period of 5 months. Three days after a final boost with 15 /ug of factor IX in saline, the spleen was removed from a mouse that had a serum anti factor IX activity of 200 NIH units measured in the standard coagulation assay. The spleen cells were fused with the HAT sensitive, nonsecreting mouse myeloma cell line, P3-NSI/1-Ag4-1 (donated by C. Milstein) using polyethylene glycol 1500 (40% w/w). After plating at 1 × 106 cells/ml in 2 ml multiwell culture plates (211 cultures) hybrid cells were selected from the mixed cell population by culturing in the presence of HAT medium for a period of 33 days. Hybrid clones of cells appeared from day 10 onwards and culture supernatants were tested for the production of antibody to factor IX in a coagulation assay.One of the cultures that produced an inhibitory effect in this assay has been subcloned twice and established as a monoclonal cell line that can be maintained in continuous culture or can be grown as an ascites tumour in syngeneic mice. This.cell line secretes an IgG1(k) antibody designated RFF-IX/I, that binds to the coagulation site of factor IX. RFF-IX/I inhibits only factor IX and no other coagulation factor. A solid-phase radiometric assay is also described that detects the presence of RFF-IX/Ia by its ability to bind to factor IX linked to polystyrene beads and that can be used to screen for production of similar antibodies by hybrid cell lines.
Modulation Of Adenylate Cyclase Activity In Platelets By β2-Glycoprotein I
Authors: Schousboe Inger 
Published: July 2018

β2GlycoProtein I, purified from human serum, has been shown to bind to negatively charged phospholipids. Such phospholipids axe essential reactants in several surface mediated reactions. In blood coagulation, platelets, to which β2-glycoprotein I recently has been shown to bind, furnish a major portion of these phospholipids. Concomitant with this binding, a change in platelet adenylate cyclase activity has been observed. The purpose of this study is to further investigate the effect of β2-glycoprotein I on the adenylate cyclase activity in platelets.Human platelets isolated immediately after bleeding were washed in buffered isotonic solutions at low ionic strength. At 0 °C intact or sonicated platelets were incubated with various concentrations of β2-glycoprotein I and prostaglandin E1xs. Intact platelets were then sonicated, platelet membranes isolated and frozen at -180 °C, and adenylate cyclase activity of the membranes determined.The results showed that adenylate cyclase activity in platelets increases about 4 times when intact platelets are preincubated with β2-glycoprotein I at saturation. This increase is also seen when low concentrations of PGE1 (≤ lµM) are present in the preincubation mixture. There was no increase in adenylate cyclase activity when sonicated platelets were incubated with β2-glycoprotein I.On the basis of these results it is suggested that in vivo β2-glycoprotein I may have one or both of the following functions, l) It may prevent circulating platelets from aggregation by protecting the negatively charged phospholipids and/or by increasing the adenylate cyclase activity and 2) it may catalyze the deaggregation of aggregated platelets.
Subcutaneous Heparin For Prophylaxis For Recurrent ThromBoembolism
Authors: Caprini J A , Thorpe C J , Torkelson S J , Vagher J P , Reyes A Z Delos , Mitchell J 
Published: July 2018

One hundred consecutive patients with thromboembolic disease were treated with subcutaneous heparin to prevent recurrence of deep venous thrombosis (70 patients), pulmonary embolus (21), or both deep venous thrombosis and pulmonary embolus (9). Thrombosis was documented by venography, doppler ultrasound, impedance plethysmography, V-P lung scanning, or pulmonary angiography. The hospitalized patients received intravenous heparin for an average of 12.3 days. Intravenous heparin was overlapped with the first dose of 5000 units of subcutaneous heparin which was then given every 12 hours. Fifteen patients had the subcutaneous dosage increased before discharge and 52 had changes in dosage at some point during therapy according to test results. Subcutaneous heparin therapy averaged 111 days per patient (range - 15 days to 16 months). No episodes of major bleeding occurred, although 5 patients had minor localized eccymosis or rash. Self-injection was well accepted and tolerated by the patients. Clinical examination, hematocrit platelet count, prothrombin time, activated partial thromboplastin time, fibrinogen, fibrin split products, and thrombelastography were performed every six weeks. Doppler and impedance plethysmography studies were repeated if clinical signs persisted or recurred. Two patients had recurrent nonfatal deep vein thrombosis 3 months after starting subcutaneous heparin therapy. Both of these patients originally had above knee thrombi.The results suggest that self-administered subcutaneous heparin injections titered to laboratory tests are effective in preventing recurrent thromboembolism without bleeding complications. This approach represents an effective alternative to oral anticoagulant therapy.