bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thrombophilic Genotypes in Subjects with Idiopathic Antiphospholipid Antibodies – Prevalence and Significance
Authors: Tommasino Catello , D’Andrea Giovanna , Iannaccone Luigi , Brancaccio Vincenzo , Margaglione Maurizio , Ames Paul 
Published: March 2018

SummaryTo evaluate the significance of common thrombophilic genotypes in subjects with idiopathic antiphospholipid antibodies (aPL) we determined the methylenetetrahydrofolate reductase C677→ (MTHFR) and factor V A506→ G (FV Leiden) polymorphisms in 49 subjects with idiopathic aPL (57% of whom suffered spontaneous vein thrombosis), in 70 subjects with a history of spontaneous vein thrombosis and in 193 healthy subjects. The prevalence of MTHFR C677→+/+ (homozygotes) was 25%, 18% and 17% respectively amongst aPL thrombotics, non aPL thrombotics and controls and that of MTHFR C677→+/– (heterozygotes) was 53%, 59% and 53% respectively in the same groups. The prevalence of FV Leiden was higher in aPL thrombotics (14%) and in non aPL thrombotics (18%) than in controls (4%) (p ≤ = 0.05). APL thrombotics with MTHFR C677→+/+ had a lower mean age at first thrombotic event (22 ± 6 years) than aPL thrombotics with MTHFR C677→+/– and non mutated considered together (38 ± 14 years, p = 0.0004) and than non aPL thrombotics with MTHFR C677→+/+ (38 ± 14 years, p = 0.003). FV Leiden may con tribute to the hypercoagulability of a small, albeit significant proportion of thrombotic aPL subjects, whereas the association between MTHFR C677→+/+ and aPL may have an impact on age at first occlusive event and suggests a possible pathogenetic interaction.
Clinical Significance of Neutrophil Adhesion Molecules Expression after Coronary Angioplasty on the Development of Restenosis
Authors: Sakai Yoshihiko , Fujito Tsuneo , Hoshi Kazuhiro , Hayashi Terumi , Takayanagi Kan , Morooka Shigenori , Inoue Teruo 
Published: March 2018

SummaryTo investigate the neutrophil activation process following percutaneous transluminal coronary angioplasty (PTCA), we examined the expressions of Mac-1 (CD11b/CD18), L-selectin (CD62L), and sialyl-LewisX (SLX) on the surface of neutrophils after the PTCA procedure, by flow cytometric analysis. Twenty-nine patients with single vessel coronary artery disease of the left anterior descending artery who underwent elective PTCA were enrolled. In the 17 patients without restenosis at the follow-up angiography, the mean channel fluorescence intensity (MFI) for CD18, CD62L and SLX did not change after PTCA. Only the CD11b level was increased at 48 h after the PTCA. In the remaining 12 patients who developed restenosis, the MFI values for CD18 and CD11b were increased at 24 h and 48 h after the PTCA. The MFI value for CD62L was decreased and that for SLX was increased at 48 h after the PTCA. These changes were more prominent in the coronary sinus blood samples than in those of the peripheral blood samples.Our data indicate the down-regulation of L-selectin, probably by shedding, as well as the up-regulations of Mac-1 and sialyl-LewisX, especially in patients with restenosis. It is suggested that neutrophil activation by an interaction between the selectin family and carbohydrate ligands after PTCA may play a role in the development of restenosis, as does the integrin family.
Beta-2-glycoprotein I Dependent Lupus Anticoagulants Form Stable Bivalent Antibody Beta-2-Glycoprotein I Complexes on Phospholipid Surfaces
Authors: Wittevrongel C. , Vanrusselt M. , Hoylaerts M. , Vermylen J. , Arnout J. 
Published: March 2018

SummaryThe precise mechanism by which Beta-2-glycoprotein I (β2GPI-) dependent lupus anticoagulants lengthen phospholipid-dependent clotting reactions is still poorly understood. In order to study this, murine monoclonal antibodies (moabs) against human β2GPI were raised. Eight of the 21 anti-β2GPI moabs, obtained from 2 fusions, fulfilled the criteria for lupus anticoagulant (LA) activity as tested with a variety of sensitive screening assays and confirmatory tests. Seven moabs did not influence any clotting test. The LA positive moabs were found to compete for similar or closely spaced epitopes on immobilized β2GPI. Two moabs with potent LA activity (moabs 22 F 6 and 22 B 3) and 1 moab without LA activity (moab 16 B 3) were selected to study the interaction between antibody, β2GPI and phospholipid. Interactions were investigated by real-time biospecific interaction analysis (BIA) based on plasmon surface resonance technology on a BIA-core instrument using a sensor chip coated with phospholipid. When 22 F 6, the moab with the most pronounced LA activity, was allowed to interact with the phospholipid surface at concentrations between 0 and 400 nmol/l, no appreciable binding could be detected. Likewise, no binding could be measured when β2GPI at concentrations between 0 and 400 nmol/l was passed over the phospholipid coated sensor chip. Combinations of β2GPI and 22 F 6 resulted in significant binding. Similar results were obtained with 22 B 3, another moab with LA activity. A LA negative Moab, 16 B 3, did not cause binding of antibody-β2GPI complexes. Fab’ fragments, derived from moab 22 F 6, inhibited the binding of β2GPI-22 F 6 and β2GPI-22 B 3 in a concentration dependent way, indicating that only bivalent β2GPI-antibody complexes bind with high affinity to phospholipids. Fab’ fragments, derived from moab 22 F 6, also inhibited the LA effect of moabs 22 F 6 and 22 B 3 in diluted plasma. In summary, these experiments indicate that the β2GPI-dependent LA effect depends on the formation of bivalent β2GPI-antibody complexes on phospholipid surfaces.
Pharmacokinetics of a Slower Clearing Tissue Plasminogen Activator Variant, TNK-tPA, in Patients with Acute Myocardial Infarction
Authors: Eppler Stephen , Breed Judy , Cannon Christopher , Braunwald Eugene , Love Ted , Modi Nishit 
Published: March 2018

SummaryThe rapid clearance of t-PA from plasma requires administration by intravenous (IV) infusion. A slower clearing, fibrin-specific rt-PA variant may allow single intravenous bolus administration, thereby simplifying dosing. This study was designed to characterize the pharmacokinetics of the slower clearing, fibrin-specific tissue-plasminogen activator variant, TNK-tPA, in patients with acute myocardial infarction (AMI) following a single IV bolus injection. Single IV bolus doses of 5 to 50 mg of TNK-tPA were studied in an open-label, multicenter, dose escalation study. A total of 113 AMI patients were enrolled. Blood sampling for pharmacokinetics was conducted in eighty-two patients (72 men, 10 women), with 5 to 27 patients per dose. TNK-tPA was administered as an IV bolus over 5–10 s. Following IV bolus administration, there was a biphasic elimination of TNK-tPA from plasma. The initial phase had a mean half-life that ranged from 11 ± 5 to 20 ± 6 min and was followed by a terminal phase with a mean half-life that ranged from 41 ± 16 to 138 ± 84 min. Mean TNK-tPA plasma clearance was 125 ± 25 - 216 ± 98 ml/min, and the initial volume of distribution was 4.3 ± 2 - 8.4 ± 6 l. A decrease in TNK-tPA plasma clearance with increasing TNK-tPA dose was noted. In addition, women and patients with lower body weight or older age had a slower plasma clearance. In conclusion, TNK-tPA has a slower plasma clearance in patients with AMI than that reported for rt-PA, allowing administration as a single IV bolus.
Flow Cytometry Analysis of Intracellular VASP Phosphorylation for the Assessment of Activating and Inhibitory Signal Transduction Pathways in Human Platelets
Authors: Schwarz Ulrike , Geiger Jörg , Walter Ulrich , Eigenthaler Martin 
Published: March 2018

SummaryIncreased platelet adhesion or aggregation are key events in the pathogenesis of cardiovascular diseases. Exact determination of the platelet activation state is essential to recognize, prevent, and treat cardiovascular complications due to platelet dysfunction. Initial phases of platelet activation and inhibition are characterized by phosphorylation of specific intracellular proteins. However, methodological problems often prevent analysis of platelet protein phosphorylation under clinical conditions. A novel flow cytometry-based method using a phosphorylation-specific antibody was developed for fast and easy quantification of the phosphorylation state of a specific intracellular platelet protein. This method was used to analyze various platelet receptors and their intracellular signaling which may be impaired in genetic or acquired disorders or altered due to therapeutic interventions. In a first clinical application, the inhibitory effects of ticlopidine and clopidogrel on the platelet P2YAC ADP receptor were monitored.Abbreviations: ADP: adenosine 5’-diphosphate; cAMP: cyclic adenosine-3’,5’-monophosphate; cGMP: cyclic guanosine-3’,5’-monophosphate; HUVECs: human umbilical vein endothelial cells; MAPK: mitogen-activated protein kinase; PG-E1: prostaglandin E1; PRP: platelet-rich plasma; SNP: sodium nitroprusside; VASP: vasodilator-stimulated phosphoprotein
D-glucose Increases the Synthesis of Tissue-type Plasminogen Activator (t-PA) in Human Peritoneal Mesothelial Cells
Authors: Mandl-Weber Sonja , Wörnle Markus , Haslinger Bettina , Goedde Martin , Kooistra Teake , Sitter Thomas 
Published: March 2018

SummaryPhysical and chemical irritation of the peritoneum through glucose-based hyperosmolar dialysis solutions results in a nonbacterial serositis with fibrinous exudation. Thereby, human peritoneal mesothelial cells (HMC) play an important role in maintaining the balance between the peritoneal generation and degradation of fibrin by expressing the fibrinolytic enzyme tissue-type plasminogen activator (t-PA) as well as the specific plasminogen activator inhibitor-1 (PAI-1). In this study, we analyzed the effect of D-glucose and metabolically inert monosaccharides on the synthesis of t-PA and PAI-1 in cultured HMC.Incubation of HMC with D-glucose or the metabolically inert monosaccharides mannitol and L-glucose (5-90 mM) resulted in a time- and concentration-dependent increase in t-PA mRNA expression and antigen secretion without affecting PAI-1 synthesis. A similar effect was evident when HMC were first exposed sequentially to pooled spent peritoneal dialysis effluent for up to 4 hours, and subsequently incubated for 20 hours in control medium. The stimulating effect of high D-glucose on t-PA expression in HMC was prevented by treating the cells with different protein kinase C (PKC) inhibitors (Ro 31-8220, Gö 6976), but could not be mimicked by the PKC-activating phorbol ester PMA, indicating that this effect of high glucose is dependent on PKC activity, but not mediated through PKC activation. Also, using specific inhibitors (PD 98059, SB 203580) and activators (PMA, anisomycin, IL-1α) of the major routes of the mitogen-activated protein kinases (MAPKs) cascade, we found no evidence for a role of this cascade in regulating t-PA expression in HMC.We conclude that hyperosmolarity induces t-PA (but not PAI-1) in HMC via a regulatory mechanism that requires active PKC, but that does not involve a major pathway in the MAPK cascade.
Thrombostatin Inhibits Induced Canine Coronary Thrombosis
Authors: Hasan Ahmed , Rebello Sam , Smith Edward , Srikanth Sujata , Werns Steven , Driscoll Edward , Faul Jessica , Brenner Dean , Normolle Daniel , Lucchesi Benedict , Schmaier Alvin 
Published: March 2018

SummaryThrombostatin (RPPGF), an angiotensin converting enzyme metabolite of bradykinin, is an inhibitor of α-thrombin’s ability to activate platelets. We examined the in vivo pharmacokinetics and pharmacodynamics of thrombostatin in rabbits and its ability to inhibit coronary thrombosis induced by electrolytic injury in dogs. Plasma half-life of thrombostatin had a t1/2α of 2.6 min and a t1/2β of 24 min in rabbits. Ligating the renal arteries did not prolong clearance (t1/2α = 2.4 min; t1/2β = 12 min). Thrombostatin produced a prolonged in vivo antiplatelet effect. At 30 min after a single intravenous administration in rabbits, thrombostatin’s plasma concentration was <8.7 μM (5 μg/ml). However, ex vivo 20 and 40 nM γ-thrombin-induced platelet aggregation of these rabbits’ platelets was inhibited 40% for 2.75 and 1 h, respectively. In vitro, flow cytometry studies revealed that thrombostatin specifically bound to human platelets and washed human platelets treated with thrombostatin were less responsive to γ-thrombin than control platelets. Using electrolytic injury to induce coronary artery thrombosis, dogs treated with thrombostatin, aspirin, or combined thrombostatin and aspirin occluded in 62 ± 25 (mean ± SD), 62 ± 36, or 89 ± 32 min versus untreated animals which occluded at 39 ± 27 min, (p <0.01, p <0.01 and p <0.001, respectively). These studies show that thrombostatin binds to platelets and can delay coronary occlusion in vivo.
Abbreviations: RPPGF: thrombostatin; PAR1: protease activated receptor 1, the first cloned thrombin receptor; PRP: platelet-rich plasma; PPP: plateletpoor plasma; LCX: left circumflex coronary artery; APTT: activated partial thromboplastin time; PT: prothrombin time
Efficacy of a Synthetic Pentasaccharide, a Pure Factor Xa Inhibitor, as an Antithrombotic Agent – A Pilot Study in the Setting of Coronary Angioplasty
Authors: Vuillemenot Alain , Schiele François , Meneveau Nicolas , Claudel Sophie , Donat François , Fontecave Sylvie , Cariou Roger , Samama Meyer , Bassand Jean-Pierre 
Published: March 2018

Summary
Aim of the study. To assess the antithrombotic properties of SR90107/ORG31540, a sulfated pentasaccharide, which enhances specifically antithrombin III mediated inactivation of factor-Xa, in a clinical setting known to promote arterial thrombosis, i.e. coronary angioplasty.
Methods and results. Percutaneous transluminal coronary angioplasty (PTCA) was carried out with conventional balloons with a single 5 min intravenous infusion of 12 mg pentasaccharide, and 500 mg intravenous aspirin. Heparin was not allowed before, during PTCA, and within 24 h after PTCA. The primary end point was the rate of abrupt vessel closure during and within 24 h after the procedure. The sample size was set at 60 evaluable patients, in order to be able to conclude with a good level of confidence (>95%) that the abrupt vessel closure rate was less than 10%, if less than 3 abrupt vessel closures were observed. Seventy-one patients were included in the study, of whom 10 needed elective stenting, and were not considered as evaluable for efficacy. Two out of the 61 remaining evaluable patients experienced acute vessel closure during the study period [3.28%, 95% confidence interval (0.4%; 11.4%)]. No major bleeding occurred. The drug plasma concentrations reached 1.91 ± 0.39 mg/l, 10 min after pentasaccharide injection, and decreased on average to 1.18 ± 0.27 mg/l at 2 h, and to 0.36 ± 0.11 mg/l at 23 h after administration of pentasaccharide. Activated clotting time (ACT) and activated partial thromboplastin (aPTT) time remained within normal range. Thrombinantithrombin complex levels fell from 22 ± 17.1 to 4.5 ± 3.4 μg/ml, prothrombin fragment 1+2 levels decreased from 2.15 ± 1.01 to 1.73 ±
0.87, and activated factor VII levels decreased from 43.4 ± 16.8 mU/ml to 18.9 ± 7.3 mU/ml respectively from baseline to 2 h following injection of the tested drug.
Conclusions. Administration of pentasaccharide led to the inhibition of thrombin generation without modification of aPTT and ACT. The rate of abrupt vessel closure was within range of rates reported in historical series. Thus we conclude that the anti-thrombotic activity of pentasaccharide, as shown in this pilot trial in the setting of coronary angioplasty, deserves further investigation.
Evaluation of an Adenoviral Vector Encoding Full-Length Human Factor VIII in Hemophiliac Mice
Authors: Connelly Sheila , Andrews Julie , Gallo-Penn Angela , Tagliavacca Luigina , Kaufman Randal , Kaleko Michael 
Published: March 2018

SummaryAdenoviral vectors provide a promising gene therapy system for the treatment of hemophilia A. Potent vectors encoding a human factor VIII (FVIII) cDNA were developed that mediated sustained FVIII expression in normal and hemophiliac mice and complete phenotypic correction of the bleeding disorder in hemophiliac mice and dogs (Connelly and Kaleko, Haemophilia 1998; 4: 380-8). However, these studies utilized vectors encoding a truncated version of the human FVIII cDNA lacking the B-domain (BDD FVIII). In this work, an adenoviral vector encoding the human full-length (FL) FVIII cDNA was generated and characterized. While functional FL FVIII was secreted in vitro, expression of the FL protein was not detected in the plasma of vector-treated hemophiliac mice. Unexpectedly, the FL FVIII vector-treated animals demonstrated phenotypic correction of the bleeding defect as measured by a tail-clip survival study. FL FVIII protein was visualized in the mouse livers using human FVIII-specific immunohistochemical analyses. These data demonstrate that adenoviral vector-mediated in vivo expression of BDD FVIII is more efficient than that of the FL protein and that phenotypic correction can occur in the absence of detectable levels of FVIII.
Fibrinogen St. Gallen I (γ 292 Gly → Val): Evidence for Structural Alterations Causing Defective Polymerization and Fibrinogenolysis
Authors: Stucki Bettina , Schmutz Peter , Schmid Luzius , Haeberli André , Lämmle Bernhard , Furlan Miha 
Published: March 2018

SummaryFibrinogen St. Gallen I was detected in an asymptomatic Swiss woman. Routine coagulation tests revealed a prolonged thrombin and reptilase time. Functionally measured fibrinogen levels were considerably lower than those determined immunologically. Polymerization of fibrin monomers derived from purified fibrinogen was delayed in the presence of either calcium or EDTA. Normal fibrinopeptide A and B release by thrombin was established. An abnormal degradation of fibrinogen St. Gallen I by plasmin was observed. Fragment D1 of normal fibrinogen was fully protected against further proteolysis in the presence of 10 mM calcium, whereas fibrinogen St. Gallen I was partially further degraded to fragments D2 and D3. In the presence of 10 mM EDTA, the conversion of variant fragment D1 to D2 was accelerated whereas the degradation of fragment D2 to D3 was delayed in comparison to degradation of fragments D1 and D2 of normal fibrinogen. Three high-affinity calcium binding sites were found in both normal and variant fibrinogen. Mutation screening with SSCP analysis suggested a mutation in exon VIII of the → Val) as previously described in fibrinogen Baltimore I (4, 5). Dysfibrinogen St. Gallen I is characterized by delayed polymerization and abnormal fibrinogenolysis compared to normal fibrinogen. Computer modeling of the variant fibrinogen revealed structural changes that may explain its abnormal functional behaviour.γ-chain gene. Cycle sequencing of this gene portion revealed a single base substitution from G to T of the base 7527, leading to replacement of γ 292 glycine by valine. The same mutation has already been described for the fibrinogen variant Baltimore I. Molecular modeling was performed of a part of the γ-chain containing the mutation site, based on recently published X-ray crystal structures of human fibrinogen fragment D and of a 30 kD C-terminal part of the γ-chain. Significant structural alterations due to the substitution of glycine by valine at γ 292 were observed, e.g. spreading of the protein backbone, probably leading to a modified accessibility of the plasmic cleavage sites in the γ-chain at 356 Lys and 302 Lys. A shift of γ 297 Asp that is involved in interactions of fragment D with the Gly-Pro-Arg-Pro-peptide was noted by molecular modeling. The latter observation is compatible with delayed polymerization of fibrin monomers.
Profile of Recombinant Pro-urokinase Given by Intraarterial versus Intravenous Routes of Administration in a Canine Thrombosis Model
Authors: Lubbers Nathan , Nelson Richard , Wegner Craig , Cox Bryan , Burke Sandra 
Published: March 2018

SummaryCatheter-directed thrombolysis has gained increasing acceptance for the treatment of patients who present with vascular occlusion; however, intravenous injection may be preferable in selected patients. Recombinant prourokinase (r-proUK) is a recently-developed fibrin-selective thrombolytic agent with specificity for clot-bound plasminogen. To compare the effects of r-proUK on clot lysis and restoration of blood flow when injected by either intraarterial or intravenous routes of administration, we utilized a dog model of arterial thrombosis in which a radiolabelled clot is formed in the femoral artery. The r-proUK was given by intravenous infusion to one group of 18 animals in doses ranging from 10,000 IU/kg to 100,000 IU/kg; a second group of 27 dogs was treated with r-proUK administered by the intra-arterial route in a dose range from 300 IU to 10,000 IU. Clot lysis was measured by monitoring the loss of counts from the radiolabelled clot over time; blood flow was also monitored throughout the experimental period. Animals which received intravenous treatment showed dose-related clot lysis ranging from 14% to 70% at 2 h, while those which received intra-arterial infusions showed lysis ranging from 22% to 79% over the same period. For similar degrees of clot lysis attained at the highest dose levels of 100,000 IU/kg and 10,000 IU, blood flow was restored to 77% and 35% of control levels in dogs which received intravenous and intraarterial treatment, respectively. The hemostatic protein fibrinogen was not reduced in any of the treatment groups. The results indicate that 100 times more intravenous than intra-arterial r-proUK is required to produce similar clot lysis in this canine model, and that the agent can be administered at this level without induction of a systemic lytic state.
Pharmacokinetics and Pharmacodynamics of Melagatran, a Novel Synthetic LMW Thrombin Inhibitor, in Patients with Acute DVT
Authors: Eriksson H. , Frison L. , Hansson P. O. , Held P. , Holmström M. , Hägg A. , Jonsson T. , Lapidus L. , Leijd B. , Stockelberg D. , Säfwenberg U. , Taghavi A. , Thorsén M. , Eriksson U. G. 
Published: March 2018

SummaryForty-eight patients with acute proximal deep vein thrombosis (DVT) were randomised to intravenous infusions for 4 to 6 days with melagatran, a novel synthetic low molecular weight thrombin inhibitor, or unfractionated heparin adjusted by the activated partial thromboplastin time (APTT). The aim of the study was to investigate the pharmacokinetics, pharmacodynamics and the safety of melagatran therapy at three different doses. Steady-state plasma concentrations were rapidly achieved and maintained throughout the infusion period. The mean plasma concentrations in the low, medium and high dose groups were 0.17, 0.31 and 0.53 μmol/l, respectively. The prolongation of APTT was stable during the melagatran infusions and correlated to the plasma concentration. Phlebographically verified regression of thrombus size measured as decrease in Marder score was seen after 4 to 6 days in 8 of 12 patients, 6 of 12 patients and 5 of 11 patients in the low, medium and high dose groups of melagatran and in 5 of the heparin-treated patients. In the low dose group with melagatran, thrombus extension was seen in one patient. At the dose levels studied, melagatran was well tolerated with no clinically significant bleeding problems, suggesting that melagatran could safely be given to patients suffering from DVT.