bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phosphorotioated Oligonucleotides Trigger Synthesis of Human Coagulation Serine Proteases
Authors: Hellstrand Kristoffer , Tarkowski Andrej , Bokarewa Maria 
Published: March 2018

SummaryCpG containing phosphorotioated oligonucleotides (ODN) are efficient adjuvants able to enhance macrophage and B cell activities. Their impact in the generation of coagulation and fibrinolytic factors has not been analysed.Production of coagulation and fibrinolytic proteins by human peripheral blood mononuclear cells (PBMC) treated with ODN was assessed.ODN induced in vitro generation of tissue factor (TF), thrombin and plasminogen, by PBMC. Synthesis of TF and thrombin occurred mostly in monocytes, while plasminogen was produced by both monocytic and lymphocytic cell populations. Generation of these proteins stimulated by CpG was totally blocked by cycloheximide, indicating the requirement of ongoing protein synthesis. Protein synthesis was equally pronounced at stimulation with cytosine-phosphate-guanosine (CpG)- and GpC- containing ODN, and dependend on the presence of the phosphorotioate moiety backbone in the ODN. Plasminogen, synthesized by monocytes and lymphocytes, was shown to be the primary product of ODN activation, leading subsequently to the expression of TF and thrombin generation.Our findings should be taken into consideration when assessing advantages and drawbacks of immunotherapy and gene therapy.
Characterization of a Ligand-attenuated Binding Site on Glycoprotein IIb/IIIa
Authors: Quinn Martin , Fullard John , Kerrigan Steven , Harriott Patrick , Cox Dermot , Fitzgerald Desmond 
Published: March 2018

SummaryWe describe an epitope on the platelet integrin, GPIIb/IIIa, identified by the monoclonal antibody, 4F8, which is attenuated by small-molecule GPIIb/IIIa ligands. 4F8 did not bind to the ligand binding pocket as it did not compete with a radiolabelled antagonist, 3H-SC-52012. This indicates that the 4F8 epitope behaves as a ligand-attenuated binding site (LABS). Ligand-induced attenuation of 4F8 was an active process as it was prevented by pretreating platelets with cytochalasin D and reduced by prostaglandin E1 or inhibition of protein kinase C. Disappearance of the epitope was required for full platelet activation as 4F8 prevented platelet aggregation without inhibiting fibrinogen binding. These results suggest a model where disappearance of the 4F8 epitope is a secondary event required for full “outside-in” signaling through GPIIb/IIIa.
F11-Receptor (F11R/JAM) Mediates Platelet Adhesion to Endothelial Cells: Role in Inflammatory Thrombosis
Authors: Babinska Anna , Ahmed Tahir , Batuman Olcay , Ehrlich Yigal , Hussain M. , Kedees Mamdouh , Athar Humra , Kornecki Elizabeth 
Published: March 2018

SummaryThe F11 receptor (F11R) is a cell adhesion molecule (CAM), member of the immunoglobulin superfamily found on the surface of human platelets, and determined to play a role in platelet aggregation, secretion, adhesion and spreading. The same molecule is present also at tight junctions of endothelial cells (EC) where it is known as JAM and acts as a CAM through homophilic interactions. The role of F11R/JAM in the interaction of platelets with endothelial cells was investigated in the current studies. We report here that washed human platelets adhere specifically to a matrix made of immobilized, recombinant sF11R. Furthermore, platelets adhere to cytokine(TNF-α, INF-γ) stimulated human umbilical vein endothelial cells (HUVEC), and approximately 40-60% of the adhesive force is exerted by homophilic interactions between the F11R of platelets and EC. This is evidenced by the inhibition of platelet adhesion to endothelial cells by recombinant soluble form of the F11R, and by two F11R peptides with amino acid sequences of the N-terminal region, and in the 1st Ig fold of the F11R, respectively. This study suggests a role for F11R in the adhesion of platelets to cytokine-inflamed endothelial cells and thus in thrombosis and atherosclerosis induced in non-denuded blood vessels by inflammatory processes. Agents that block the F11R-mediated adhesion of platelets to EC may be of therapeutic value in controlling thrombosis and preventing heart attacks and stroke.
Ultrasound Improves Tissue Perfusion in Ischemic Tissue through a Nitric Oxide Dependent Mechanism
Authors: Suchkova Valentina , Baggs Raymond , Sahni Sanjeev , Francis Charles 
Published: March 2018

SummaryUltrasound accelerates enzymatic fibrinolysis in vitro and in animal models and may be used as an adjunct to thrombolytic therapy. Ultrasound can also affect vascular tone directly, and we have now investigated the effect of ultrasound on tissue perfusion in a rabbit model of acute muscle ischemia to characterize the magnitude and temporal course of vasodilation and determine its mechanism. After ligation of the femoral artery of rabbits, tissue perfusion in the gracilis muscle as determined using a laser Doppler probe declined by 53% from 13.7 ± 0.3 U to 6.4 ± 0.2 U. The tissue became acidotic as pH declined from normal to 7.05 ± 0.2. Application of 40 kHz ultrasound at intensities from 0.25 to 0.75 W/cm2 progressively improved perfusion over 60 min and reversed acidosis, but these effects were both completely blocked by pre-treatment with the nitric oxide synthase inhibitor LNAME. Nitric oxide synthase activity in muscle was measured using an assay based on the conversion of radiolabeled L-arginine to L-citrulline and demonstrated an increase of 3.6-fold following ultrasound exposure. This effect was greatest at locations close to the transducer and declined progressively away from it. Histologic examination showed greater capillary circumference in ultrasound exposed muscle compared to unexposed tissue with no other histologic changes. We conclude that the application of 40 kHz at low intensity improves perfusion and reverses acidosis in acutely ischemic muscle through a nitric oxide dependent mechanism.
Diacylglycerol Kinases: Regulation and Signaling Roles
Authors: Prescott Stephen , Topham Matthew 
Published: March 2018

SummaryDiacylglycerol kinases (DGKs) are thought to attenuate diacylglycerol signals by converting diacylglycerol to phosphatidic acid. The nine mammalian diacylglycerol kinases that have been identified are widely expressed, but each isoform has a unique tissue and subcellular distribution. The activity of DGKs is regulated by mechanisms that can modify their access to diacylglycerol, affect their activity, or alter their ability to bind to other proteins. Although little is known of the specific function of DGKs in platelets, they likely influence actin reorganization and other signaling events requiring diacylglycerol.
Multicentre Evaluation of IL Test™ Free PS: A Fully Automated Assay to Quantify Free Protein S
Authors: Sales Miquel , Chitolie Andrew , Domènech Pere , Rossi Edoardo , Borrell Montserrat , Dahlbäck Björn , Serra Josep 
Published: March 2018

SummaryDeficiency of the anticoagulant vitamin K-dependent protein S (PS) is associated with increased risk of venous thrombosis. In human plasma, PS circulates in two forms: as free protein (free PS) and PS bound to C4b-binding protein (C4BP), a regulator of the complement system. Assays for free PS have higher sensitivity and specificity for protein S deficiency than assays for total protein S. We have extensively evaluated the analytical performance of a novel assay for free PS, the IL Test™ Free Protein S, which takes advantage of the affinity of C4BP for free PS, and compared its performance to existing methods. IL Test™ Free Protein S is a rapid, fully automated turbidimetric assay consisting of two reagents: a C4BP coated latex and an anti-PS monoclonal antibody coated latex. The test range, precision and linearity were adequate and the assay tolerated high concentrations of interfering substances of clinical significance. The reference range agreed with previously published studies. The analysis of 903 patient samples belonging to 20 different clinical categories with the new assay yielded free PS results that agreed well with those obtained using the assays established in the participating laboratories. The study demonstrated the IL Test™ Free Protein S to be rapid, reliable and easy to perform.
Pathogenic Effects of Anti-Glycoprotein Ib Antibodies on Megakaryocytes and Platelets
Authors: Alimardani Gulie , Guichard Josette , Fichelson Serge , Cramer Elisabeth 
Published: March 2018

SummaryAntibodies directed against the glycoprotein (GP) Ib have been identified as the potential cause of various platelet disorders: Immune thrombocytopenic purpura (ITP) may be caused by such autoantibodies; Anti-thrombotic drugs targeting GPIb also induce thrombocytopenia. In order to elucidate the potential mechanism(s) of the anti-GPIb effects, we have examined by electron microscopy (EM) the effect of several antibodies directed against GPIb and GPIIb-IIIa on human culture megakaryocytes (MK). Virtually all antibodies to GPIb enhanced the interaction of newly formed platelets with MK when compared to other antibodies. These effects were retrieved when antibodies were tested on platelets. We conclude that antibodies to GPIb can potentially inhibit platelet release by MK, and can also induce homotypic platelet adhesion. These results may have implications in the pathophysiology of thrombocytopenia and platelet recovery in ITP, and shed light on the pathological effect of anti-GPIb antibodies used as antithrombotic drugs.
Different mechanisms contribute to the biphasic pattern of carboxypeptidase U (TAFIa) generation during in vitro clot lysis in human plasma
Authors: Leurs Judith , Wissing Britt-Marie , Nerme Viveca , Schatteman Katinka , Björquist Petter , Hendriks Dirk 
Published: March 2018

SummaryCarboxypeptidase U (CPU, TAFIa) recently gained interest as a significant player in dampening the fibrinolytic rate. The aim of this study was to investigate the time course of the generation of CPU activity during coagulation and fibrinolysis using an in vitro clot lysis model in human plasma. A first peak of CPU activity appeared after initiation of the coagulation phase and a second rise in CPU activity was observed during the fibrinolysis. The decrease in the proCPU plasma concentration followed the same trend as the appearance of the CPU activity. The direct thrombin inhibitor inogatran eliminated the CPU generation during coagulation but not during fibrinolysis. Addition of the plasmin inhibitor aprotinin during fibrinolysis resulted in a decrease in CPU activation during the lysis phase. These results demonstrate that proCPU was activated during coagulation by thrombin and during fibrinolysis by plasmin. Addition of a CPU inhibitor before initiation of clotting decreased the clot lysis time as expected. However, addition in the time period between the two peaks of CPU activity had no apparent effect on the clot lysis time.
Prospective assessment of the natural history of positive D-dimer results in persons with acute venous thromboembolism (DVT or PE)
Authors: Kuruvilla John , Wells Phil , Morrow Bev , MacKinnon Karen , Keeney Michael , Kovacs Michael 
Published: March 2018

SummaryThe natural history of initially positive D-dimers for venous thromboembolism is not known. If it returns to negative in the majority of patients, it would be potentially helpful to diagnose a recurrence. In this study, we prospectively measured D-dimer levels in outpatients with a diagnosis of venous thrombo-embolism. There were a total of 152 patients with an average age of 57. D-dimer results were performed at baseline and repeated at one week, one month and three months.At baseline 120 of 152 (79%) had a positive D-dimer result. Of those with an initially positive result, 80% were still positive at one week and 39% were still positive at one month. Finally at three months, 13% remained positive. Seven patients had recurrent events and all had persistently elevated D-dimers at one month. This study suggests that a persistently positive D-dimer result after one month of treatment may indicate a higher risk of recurrent venous thromboembolism. D-dimer testing for the diagnosis of recurrence of venous thromboembolism deserves further study.
Direct thrombin inhibitor melagatran followed by oral ximelagatran in comparison with enoxaparin for prevention of venous thromboembolism after total hip or knee replacement
Authors: Agnelli Giancarlo , Cohen Alexander , Dahl Ola , Mouret Patrick , Rosencher Nadia , Eskilson Christina , Nylander Ingela , Frison Lars , ögren Mats , Eriksson Bengt ,   on behalf of the METHRO III Study Group* (* see Appendix for METHRO III study participants)
Published: March 2018

SummaryWe evaluated whether a postoperative regimen with melagatran followed by oral ximelagatran, two new direct thrombin inhibitors, was an optimal regimen for thromboprophylaxis in major orthopaedic surgery. In a double-blind study, 2788 patients undergoing total hip or knee replacement were randomly assigned to receive for 8 to 11 days either 3 mg of subcutaneous melagatran started 4-12 h postoperatively, followed by 24 mg of oral ximelagatran twice-daily or 40 mg of subcutaneous enoxaparin once-daily, started 12 h preoperatively. Ximelagatran was to be initiated within the first two postoperative days. The primary efficacy endpoint was venous thromboembolism (deep-vein thrombosis detected by mandatory venography, pulmonary embolism or unexplained death). The main safety endpoint was bleeding. Venous thromboembolism occurred in 355/1146 (31.0%) and 306/1122 (27.3%) patients in the ximelagatran and enoxaparin group, respectively, a difference in risk of 3.7% in favour of enoxaparin (p = 0.053). Bleeding was comparable between the two groups.
Effect of fibrinogen concentration and platelet count on the inhibitory effect of abciximab and tirofiban
Authors: Renda Giulia , Rocca Bianca , Crocchiolo Roberto , De Cristofaro Raimondo , Landolfi Raffaele 
Published: March 2018

SummaryGlycoprotein (Gp) IIb/IIIa blockers are powerful antithrombotic agents, but display a wide variability of their effect using weight-adjusted dosing. We investigated whether some hemostatic variables affected in vitro platelet inhibition exerted by the antibody abciximab and the peptidomimetic tirofiban. High fibrinogen concentrations reduced platelet inhibition by tirofiban, assessed in whole blood (r = –0.85, n = 10, p <0.01) and in platelet rich plasma (r = –0.89, n = 10, p <0.01) through PFA 100 and Born’s aggregometry assay, respectively. Both drugs were unaffected by von Willebrand factor levels, while platelet count was inversely related to their inhibitory effect (tirofiban: r = –0.9, n = 7, p <0.01; abciximab: r = –0.81, n = 9, p <0.01). Analysis of GpIIb-IIIa blockade showed that receptor occupancy at a fixed abciximab dose was inversely related to platelet counts. These experimental data were in agreement with the classical model of receptor saturation by a tight binding inhibitor.A role for fibrinogen and/or platelet count in influencing the antithrombotic properties of platelet GpIIb-IIIa antagonists can be hypothesized.
Blood coagulation and fibrinolytic factors in 105 patients with hemorrhagic syndrome caused by accidental contact with Lonomia obliqua caterpillar in Santa Catarina, Southern Brazil
Authors: Zannin Marlene , Lourenço Dayse , Motta Guacyara , Dalla Costa Luis , Grando Margaret , Gamborgi Geni , Noguti Maria , Chudzinski-Tavassi Ana 
Published: March 2018

SummaryHaemostatic disorders caused by Lonomia obliqua caterpillars has reached epidemic proportions in southern Brazil. Here we evaluated coagulation and fibrinolysis in 105 patients after accidental contact with Lonomia obliqua caterpillars. Global coagulation tests were prolonged in most cases and patients were divided into 3 groups according to fibrinogen (Fg) level: 0.5 g/l (group A); 0.51–1.5 g/l (group B), >1.5 g/l (group C). There was a significant reduction of factors V, XIII, VIII and prekallikrein in group A, with no change in factors X, II and von Willebrand factor. Thrombin-antithrombin and prothrombin F1+2 were elevated in most patients. Antithrombin and protein S were not changed whereas protein C levels were reduced in group A. Plasminogen and alfa2-antiplasmin levels were significantly reduced in group A and D-Dimer levels were extremely high in all groups, showing that fibrinolysis had been activated, possibly secondary to fibrin production. Levels of t-PA were normal and PAI-1 was mildly elevated in group A. The platelet count remained above 150 × 109 platelets/ml in 97% of cases. In summary, our results suggest that Lonomia obliqua envenoming is characterized by a consumption coagulopathy and secondary fibrinolysis.
The preparation and phospholipid binding property of the C2 domain of human factor VIII
Authors: Takeshima Kazuya , Smith Christina , Tait Jonathan , Fujikawa Kazuo 
Published: March 2018

SummaryThe C2 domain of human factor VIII was expressed in a yeast secretion system and its binding properties were studied. A cDNA coding the C2 domain sequence of human factor VIII with a N-terminal six amino acids extension (C-C2) was constructed, transformed into Pichia pastoris cells and expressed. The product was purified by ammonium sulfate fractionation and anion exchange chromatography. It emerged as a single peak from both ion exchange and gel filtration columns, indicating C-C2 is a homogenous monomer. The binding activity of C-C2 to phosphatidylserine-containing phospholipid vesicles was measured by competitive binding with annexin V. The values of IC50were approximately 70nM for both factor VIII and its light chain, but were about 7000nM for C-C2. These results indicated C-C2 has 100-fold less binding affinity than factor VIII or the light chain. Direct binding to solidified phosphatidylserine-containing phospholipids also showed that C-C2 has ~50-fold less binding affinity than does the light chain. C-C2 poorly inhibited Xase activity. These results together clearly show that the C2 domain alone does not have full membrane binding activity, and suggest that the other light chain domains, A3 and/or C1, are also involved in the phospholipid binding activity of factor VIII.
Evidence of prolonged disturbances in the haemostatic, hemorheologic and inflammatory profiles in transmural myocardial infarction survivors
Authors: Saldanha Carlota , Monteiro José , Perdigão Carlos , eSilva João Martins , Sargento Luis 
Published: March 2018

SummaryHaemostatic, hemorheologic and inflammatory disturbances have been associated with acute coronary syndromes. Most knowledge is reported in cross sectional studies and are without time dependent evolution of these profiles.The aim of this study was to evaluate, during the first year, the evolution of the haemostatic, hemorheologic and inflammatory profiles determined at hospital discharge in survivors with transmural myocardial infarction (MI).Eighty eight (79 male; 9 female) mean age of 58 ± 11 years, survivors of a transmural MI were prospectively studied at discharge, 6 months and one year after the event. Haemostatic (protein C, antithrombin III and plasminogen activator inhibitor 1), hemorheologic (blood fluidity and components) and inflammatory profiles (polymorphonuclear elastase and leukocyte count) were determined using standard methodology.The results of the study can be summarized as follows: (1) Protein C decreased (p < 0.05) over time while PAI-1 only varied significantly until 6th month. (2) Plasma viscosity and fibrinogen (p < 0.001) decrease over time, while erythrocyte aggregation (p < 0.001) and haematocrit increased. Whole blood viscosity did not vary. (3) Leukocyte decreased (p < 0.001) and elastase did not (4). Those patients with cardiovascular events (n = 7) had higher PAI-1 concentration (p<0.05) and leukocyte count (p < 0.01), at discharge (5) Left ventricle ejection fraction correlated significantly with plasma viscosity (r = 0.35 p < 0.05). The results of this longitudinal study show dynamic modifications of the haemostatic, hemorheologic and inflammatory profiles during the first year of a transmural myocardial infarction. In addition, there are interrelations between them and the clinical profile that could help to explain the clinical evolution of this group of patients.
Urokinase-induced migration of human vascular smooth muscle cells requires coupling of the small GTPases RhoA and Rac1 to the Tyk2/PI3-K signalling pathway
Authors: Tkachuk Natalia , Haller Hermann , Dumler Inna , Kiian Ioulia 
Published: March 2018

SummaryUrokinase-type plasminogen activator (uPA) facilitates cell migration by localizing proteolisys on the cell surface and by inducing intracellular signalling pathways. In human vascular smooth muscle cell (VSMC) uPA stimulates migration via the uPA receptor (uPAR) signalling complex containing the Janus kinase Tyk2 and phosphatidylinositol 3-kinase (PI3-K). We report that active GTP-bound forms of small GTPases RhoA and Rac1, but not Cdc42, are directly associated with Tyk2 and PI3-K in an uPA/uPAR-dependent fashion. Endogenous RhoA, but not Rac1 or Cdc42, was significantly activated in response to uPA. RhoA activation was abolished by cell treatment with two unrelated, structurally distinct, specific inhibitors of PI3-K, wortmannin, and LY294002. Downstream of RhoA, phosphorylation of myosin light chain (MLC) was dramatically upregulated by uPA in a Rho kinase- and PI3-K-dependent manner. Thus, selective Rho kinase inhibitor Y27632 and PI3-K inhibitors wortmannin and LY294002 prevented the uPA-induced stimulation of MLC phosphorylation. Rho kinase inhibition also decreased uPA-stimulated VSMC migration as observed in a Boyden chamber. VSMC immunocytochemical staining demonstrated redistribution of RhoA and Rac1 active forms to the newly formed leading edge of migrating cell. VSMC microinjection with antibodies to either Rho or Rac1 decreased uPA-stimulated cell migration, indicating the involvement of both GTPases in the migration process. Our results provide evidence that the small GTPases RhoA and Rac1, together with Rho kinase, are necessary to mediate the uPA/uPAR-directed migration via the Tyk2/PI3-K signalling complex in human VSMC.
Independence of growth factor induced plasminogen activator inhibitor type-1 (PAI-1) expression from the 4G/5G polymorphism of the PAI-1 gene
Authors: Eschenfelder Esther , Peter Karlheinz , Sobel Burton , Bode Christoph , Nordt Thomas 
Published: March 2018

SummaryIncreased PAI-1 expression has been implicated in accelerating atherogenesis. Increases under some conditions are modulated by growth factors. Genetic factors such as the 4G/5G poly-morphism in the promoter of the PAI-1 gene play a role under certain circumstances. The present study was designed to delineate for the first time interactions between growth factors and the 4G/5G polymorphism with respect to PAI-1 expression in human arterial smooth muscle cells (HASMC).HASMC were genotyped and exposed to growth factors. PAI-1 gene and protein expression were induced consistently by TGF-β (up to 4.0-fold), PDGF (2.1-fold),TNF-α (1.7-fold), and thrombin (2.3-fold). Results were similar regardless of which genotype (4G/4G [n=9], 4G/5G [n=13], and 5G/5G [n=7]) was present.The induction of increased PAI-1 expression in human arterial smooth muscle cells by growth factors implicated in accelerated atherogenesis is independent of the PAI-1 4G/5G polymorphism. Accordingly, modulation of PAI-1 expression is likely to be influenced predominantly by environmental factors acting on, rather than genetic factors intrinsic to the PAI-1 promoter.