bluuebunny/crossref_metadata_2025_split huggingface dataset:
An important role for the activation peptide domain in controlling factor IX levels in the blood of haemophilia B mice
Authors: Begbie Megan E. , Mamdani Asif , Gataiance Sharon , Eltringham-Smith Louise J. , Bhakta Varsha , Hortelano Gonzalo , Sheffield William P. 
Published: November 2005

SummaryThe factors responsible for the removal of injected factor IX (fIX) from the blood of individuals with haemophilia B are only partly understood, and may include binding to endothelial or subendothelial sites, passive extravasation related to size or charge, or interactions requiring fIX activation. To investigate these issues, we have produced and characterised recombinant fIX proteins with amino acid changes: Δ155–177, an internal deletion which removes most of the activation peptide while retaining the activation cleavage sites; S365A, which inactivates the serine protease activity of fIXa; and K5A, previously shown to eliminate fIX binding of endothelial/subendothelial collagen IV. All proteins were expressed in stably transfected HEK 293 cells, purified by immunoaffinity chromatography, and compared to the wild type HEK 293-derived protein (fIX (WT)). Mutant fIX proteins K5A and Δ155–177 exhibited 72 and 202% of the specific activity of fIX (WT), respectively; S365A was without activity. Following intravenous injection in haemophilia B (fIX knockout) mice, recoveries did not differ for fIX (WT) and Δ155–177, but were higher for K5A and S365A. The terminal catabolic halflife of Δ155–177, alone among the mutants, was increased, by 45% versus fIX (WT). Nine hours post-injection, the observed areas under the clearance curve (AUCs) of Δ155–177 and K5, but not S365A, were elevated 2-fold. Δ155–177 was equally effective as fIX (WT) in reducing blood loss following tail vein transection in haemophilia B mice. Our results suggest that deletion of the multiple sites of fIX post-translational modification found within the activation peptide eliminated important fIX clearance motifs.
Platelet adhesion: Structural and functional diversity of short dystrophin and utrophins in the formation of dystrophinassociated-protein complexes related to actin dynamics
Authors: Cerecedo Doris , Martínez-Rojas Dalila , Chávez Oscar , Martínez-Pérez Francisco , García-Sierra Francisco , Rendon Álvaro , Mornet Dominique , Mondragón Ricardo 
Published: November 2005

SummaryPlatelets are dynamic cell fragments that modify their shape during activation. Utrophin and dystrophins are minor actin-binding proteins present in muscle and non-muscle cytoskeleton. In the present study, we characterised the pattern of Dp71 isoforms and utrophin gene products by immunoblot in human platelets. Two new dystrophin isoforms were found, Dp71f and Dp71d, as well as the Up71 isoform and the dystrophin-associated proteins, α and β-dystrobrevins. Distribution of Dp71d/Dp71Δ110
m, Up400/Up71 and dystrophin-associated proteins in relation to the actin cytoskeleton was evaluated by confocal microscopy in both resting and platelets adhered on glass. Formation of two dystrophin-associated protein complexes (Dp71d/Dp71Δ110
m ~DAPC and Up400/Up71~DAPC) was demonstrated by co-immunoprecipitation and their distribution in relation to the actin cytoskeleton was characterised during platelet adhesion. The Dp71d/Dp71Δ110
m ~DAPC is maintained mainly at the granulomere and is associated with dynamic structures during activation by adhesion to thrombin-coated surfaces. Participation of both Dp71d/Dp71Δ110
m ~DAPC and Up400/Up71~DAPC in the biological roles of the platelets is discussed.
Inverse relationship between plasminogen activator inhibitor-1 activity and adiponectin in overweight and obese women
Authors: Mertens Ilse , Ballaux Dominique , Funahashi Tohru , Matsuzawa Yuji , Planken Marc Van der , Verrijken An , Ruige Johannes B. , Van Gaal Luc F. 
Published: November 2005

SummaryAdipose tissue is an active endocrine organ secreting different adipokines such as plasminogen activator inhibitor-1 (PAI-1) and adiponectin, among many others. In this study, we investigated the association between PAI-1 activity and serum adiponectin levels in a group of 444 overweight and obese women and assessed the interrelationship with visceral adipose tissue (VAT; CT-scan L4-L5), insulin resistance (HOMA-IR), HDL cholesterol (HDL-chol) and inflammation (hs-CRP). PAI-1 was inversely related to adiponectin (r=-0.25, p<0.001; adjusted for age and BMI).After adjustment for age, VAT, HOMA-IR and hs-CRP, the relationship remained significant (r=-0.15; p=0.001), but disappeared after additional adjustment for HDL-chol (r=-0.09; p=0.067). Subjects were divided in two groups according to the median levels of adiponectin or PAI-1 levels. PAI-1 activity (19.1±11.4 vs. 15.8±8.6 AU/ml; p=0.003) and adiponectin levels (9.8±4.6 vs. 8.4±4.0 μg/ml; p<0.001) were significantly higher in the low adiponectin/PAI-1 groups. The difference in PAI-1 remained significant after adjustment for age and BMI (p=0.001), became borderline significant after adjustment for age and VAT (p=0.052), and disappeared after adjustment for age and HOMA-IR (p=0.116) or age and HDL-chol (p=0.443).The difference in adiponectin levels remained significant after adjustment for age, VAT, HOMA-IR and hs-CRP (p=0.006), but disappeared after additional adjustment for HDL-chol (p=0.089). Further analyses suggest a contribution of HOMA-IR and/or HDL-chol in the relationship between PAI-1 and adiponectin. HDL-chol was found to be the only factor independently determining both factors. In conclusion, in overweight and obese women, PAI-1 activity was inversely related to serum adiponectin, independent of visceral adipose tissue.
The effects of supra-normal protein C levels on markers of coagulation, fibrinolysis and inflammation in a human model of endotoxemia
Authors: Spiel Alexander O. , Firbas Christa , Mayr Florian B. , Leitner Judith M. , Schmidt Bily , Knöbl Paul , Varadi Katalin , Jilma Bernd 
Published: November 2005

SummaryThe protein C pathway serves as a modulating system with both anti-inflammatory and anticoagulant properties and is intimately involved in the pathophysiology of inflammation and sepsis. Treatment with recombinant human activated protein C (rhAPC) can reduce the mortality of severe sepsis. We investigated whether an elevation of plasma protein C levels to supranormal levels by infusion of a protein C zymogen concentrate has an effect on coagulation, protein C activation or inflammation in a human endotoxemia model. Eleven healthy male volunteers were enrolled in a double-blind, placebo-controlled two-way cross-over trial. Ten minutes after infusion of 2ng/kg endotoxin each volunteer received either placebo or a plasmaderived protein C zymogen concentrate (Ceprotin®, Baxter) (150 U/kg as a slow bolus infusion followed by 30 U/kg/h continuous infusion until 4 hours after LPS-infusion). Protein C antigen and activity increased 4– to 5-fold after infusion of the concentrate. APC was generated during endotoxin-induced inflammation in the placebo (1.6 fold increase) and the protein C period (4.0-fold increase).The increase of APC levels correlated with the TNF-α and IL-6 release in both periods (r=0.65–0.68; p<0.05) and paralleled the protein C antigen and activity levels in the period with supranormal protein C levels. Supra normal protein C levels resulted in slightly, although non-significant, lower tissue factor mRNA expression and thrombin generation (TAT, F1+2). Systemic inflammation (TNF-α, IL-6) was not influenced by protein C zymogen concentrate administration. Infusion of protein C zymogen was safe and no adverse effects occurred. The increase of protein C levels several fold above the normal range resulted in a proportional increase of the APC levels, but had no major anticoagulant, anti-inflammatory or profibrinolytic effects. Low grade endotoxemia itself induces significant protein C activation, which correlates with the TNF release.
Endurance training reduces circulating asymmetric dimethylarginine and myeloperoxidase levels in persons at risk of coronary events
Authors: Penka Martina , Grdić Marija , Steiner Sabine , Strasser Barbara , Ziegler Sophie , Zorn Gerlinde , Maurer Gerald , Simeon-Rudolf Vera , Wojta Johann , Huber Kurt , Richter Bernhard , Niessner Alexander 
Published: November 2005

SummaryAsymmetric dimethylarginine (ADMA), myeloperoxidase (MPO) and paraoxonase 1 (PON1) are directly involved in the pathogenesis of atherosclerosis by modulation of oxidative stress and/or NO bioavailability. We aimed to assess whether endurance exercise which is known to be cardioprotective could beneficially affect these novel risk markers. Thirty-two subjects (31–68 yrs, 56% males) with elevated cardiovascular risk including ten patients with coronary artery disease volunteered for a supervised 12-week endurance training (196 ± 15 min/week).Their fitness evaluated by 2 km test runs improved significantly after training (pre: 17.3±0.8 vs. post: 15.7±0.9min, p<0.001). ADMA (pre: 0.94±0.03 vs. post: 0.75±0.04 μmol l−1) and MPO (pre:296.8±22.2 vs.post:185.7±19.5 ng ml−1) serum levels decreased significantly by 17.6±4.6% and 28.5±7.5%, respectively, after training (both p<0.001).Their down-regulation was inversely correlated (ADMA: r=-0.609, p<0.001, MPO: r=-0.437, p=0.014) with the up-regulation of plasma cGMP levels (Cyclic-guanosine 3`,5`-monophosphate; pre: 1.6±0.12 vs. post: 2.21±0.2 μmol ml−1, p=0.001) reflecting NO production. PON1 activity towards phenylacetate was not significantly influenced by training (pre: 133±6 vs. post: 130±5 μmol ml−1 min−1, p=0.375). In a matched inactive control group (n=16) ADMA, MPO, cGMP levels and PON1 activity did not change over time. ADMA, MPO and cGMP changes were significantly different between participants and controls (all p<0.05). Regular endurance exercise was successful in reducing the circulating levels of two promising cardiovascular risk markers, ADMA and MPO, in persons prone to cardiac events. These changes may result in numerous antiatherosclerotic effects such as improvement of NO bioavailability, reduction of oxidative stress and lipid peroxidation.
Functional heterogeneity of alloantibodies against the human platelet antigen (HPA)-1a
Authors: Kroll Hartmut , Penke Gabriele , Santoso Sentot 
Published: November 2005

SummaryThe integrin αIIbβ3 is the major fibrinogen receptor on the platelet membrane and plays a crucial role for platelet aggregation. The β3-subunit carries the human platelet alloantigen (HPA)-1a, which is the main target for alloantibodies (alloabs) responsible for foetal and neonatal alloimmune thrombocytopenia (FNAIT) and post-transfusion purpura (PTP).Whereas PTP is almost invariably associated with severe bleeding, the clinical presentation of FNAIT ranges from mild thrombocytopenia to severe haemorrhagic diathesis. However, this clinical heterogeneity is not fully understood as it is not explained solely by the variability of the platelet count. Here, we examined the ability of HPA-1a alloabs from mothers with FNAIT (n = 43) and PTP patients (n = 8) to inhibit cell adhesion to fibrinogen and asked if this inhibition was correlated with the heterogeneity of the clinical picture. Stably transfected cells expressing HPA-1a (β3-Leu33) and –1b (β3-Pro33) isoforms were incubated with sera containing HPA-1a alloabs and were allowed to adhere to immobilised fibrinogen. The inhibitory activity was measured as percentage of cell adhesion in the presence of patient sera versus normalAB serum. Only two FNAIT sera specifically inhibited the adhesion of HPA-1a, but not HPA-1b cells. Two other FNAIT sera blocked the adhesion of HPA-1a as well as HPA-1b cells. Interestingly, all four neonates with inhibitory HPA-1a alloabs (9% of all sera) suffered severe bleeding. In comparison, the majority of PTP sera (75%) inhibited cell binding to fibrinogen, four PTP sera selectively inhibited the adhesion of HPA-1a cells whilst 2 sera impaired the binding of both allotypes. Our observations indicate that 1) HPA-1a alloabs are heterogeneous in their ability to interfere with fibrinogen binding, and 2) inhibition of the αIIbβ3 fibrinogen receptor by HPA-1a alloabs may contribute to pronounced bleeding in patients with alloimmune thrombocytopenia.
Urokinase plasminogen activator released by alveolar epithelial cells modulates alveolar epithelial repair in vitro
Authors: Leer Coretta Van , Stutz Monika , Haeberli André , Geiser Thomas 
Published: November 2005

SummaryIntra-alveolar fibrin is formed following lung injury and inflammation and may contribute to the development of pulmonary fibrosis. Fibrin turnover is altered in patients with pulmonary fibrosis, resulting in intra-alveolar fibrin accumulation, mainly due to decreased fibrinolysis. Alveolar type II epithelial cells (AEC) repair the injured alveolar epithelium by migrating over the provisional fibrin matrix. We hypothesized that repairing alveolar epithelial cells modulate the underlying fibrin matrix by release of fibrinolytic activity, and that the degree of fibrinolysis modulates alveolar epithelial repair on fibrin. To test this hypothesis we studied alveolar epithelial wound repair in vitro using a modified epithelial wound repair model with human A549 alveolar epithelial cells cultured on a fibrin matrix. In presence of the inflammatory cytokine interleukin-1β, wounds increase by 800% in 24 hours mainly due to detachment of the cells, whereas in serum-free medium wound areas decreases by 22.4 ± 5.2 % (p<0.01). Increased levels of D-dimer, FDP and uPA in the cell supernatant of IL-1β-stimulated A549 epithelial cells indicate activation of fibrinolysis by activation of the plasmin system. In presence of low concentrations of fibrinolysis inhibitors, including specific blocking anti-uPA antibodies, alveolar epithelial repair in vitro was improved, whereas in presence of high concentrations of fibrinolysis inhibitors, a decrease was observed mainly due to decreased spreading and migration of cells. These findings suggest the existence of a fibrinolytic optimum at which alveolar epithelial repair in vitro is most efficient. In conclusion, uPA released by AEC alters alveolar epithelial repair in vitro by modulating the underlying fibrin matrix.
Dose-finding and pharmacokinetics of therapeutic doses of tinzaparin in pediatric patients with thromboembolic events
Authors: Kuhle Stefan , Massicotte Patti , Dinyari Maria , Vegh Patsy , Mitchell Debra , Marzinotto Velma , Chan Antony , Pieniaszek Hank , Mitchell Lesley G. 
Published: November 2005

SummaryIn children, there is an increasing off-label use of low molecular weight heparin (LMWH). However, there is an absence of information on dosing and pharmacokinetics of LMWH over all age groups. The objectives of the current study were to determine i) the once daily dose required to achieve anti-Xa levels of 0.5–1.0 IU/mL, ii) the pharmacokinetics and iii) preliminary safety data using tinzaparin. The study took the form of a single centre open-label Phase II study performed in 35 children requiring anticoagulation for treatment of thromboembolism. Age groups studied were: 0-<2 months; 2 months-<1 year; 1-<5 years; 5-<10 years; 10–16 years. Both population pharmacokinetic analysis using nonlinear mixed-effect modeling techniques and model-independent pharmacokinetic methods were employed. Results showed a relationship of age and dose requirements, clearance, time to peak anti-Xa level and volume of distribution. Younger children required an increased dose, cleared tinzaparin more rapidly, had anti-Xa levels peak earlier and had an increased volume of distribution. Younger children were more likely to be below target range than older children, with up to 75% of children <1 year being below the target anti-Xa level. Four recurrences and one major bleed occurred. In conclusion, there is an inverse relationship of age on dose requirements related to volume of distribution, clearance and time to peak anti- Xa. Children <5 years likely require dose adjustment samples to be drawn 2–3 hours post injection. Infants require anti-Xa levels to be monitored at least twice monthly.
The first assessment of soluble CD146 in women with unexplained pregnancy loss
Authors: Bardin Nathalie , Martin Luc De Saint , Le Martelot Marie Thérèse , Bohec Caroline , Roche Sylvie , Mottier Dominique , Dignat-George Françoise , Pasquier Elisabeth 
Published: November 2005

SummaryThe mechanisms responsible for pregnancy loss have not all been elucidated. CD146 is a cell adhesion molecule involved in the control of both endothelium integrity and intermediate trophoblast invasiveness, two potential key features in the pathogenesis of pregnancy loss. As CD146 is detectable as a soluble form in the plasma (sCD146), we investigated sCD146 plasma levels in women with a history of pregnancy loss. We conducted a paired case-control study to compare sCD146 plasma levels in 100 women with unexplained pregnancy losses (2 or more consecutive losses at or before 21 weeks of gestation, or at least one later loss) and in 100 age-matched control women (no pregnancy loss and at least one living child). The sCD146 concentrations were determined at least 2 months after the last obstetrical event. Patients and controls were comparable regarding thrombophilia. Among the patients, 83 women experienced early pregnancy losses (average of 3 losses, mean gestation of 6.6 weeks) and 22 women suffered at least one late pregnancy loss. We found significantly higher sCD146 plasma levels in the 100 patients compared to age matched control women (p<0.001). The sCD146 plasma levels did not correlate with the number of pregnancy losses nor with the mean gestation time. Alterations in sCD146 plasma levels could be related to endothelial dysfunction associated to defective endovascular trophoblast invasiveness. Additional studies should explore whether sCD146 assessment could provide diagnostic and prognostic information with a view to screening and thus managing women with unexplained pregnancy loss.
Is factor V Leiden a risk factor for thrombotic microangiopathies without severe ADAMTS13 deficiency?
Authors: Krieg Soraya , Studt Jan-Dirk , Sulzer Irmela , Lämmle Bernhard , Hovinga Johanna A. Kremer 
Published: November 2005

SummaryAbout 60% of patients diagnosed with acute thrombotic thrombocytopenic purpura (TTP) display a severe ADAMTS13 deficiency. Recently, Raife et al. concluded from a small case series, that factor V Leiden (FVL) might constitute a risk factor for acute thrombotic microangiopathy (TMA) without severe ADAMTS13 deficiency. Therefore, we determined ADAMTS13 activity and FVL carrier-ship in 256 consecutive patients presenting with various forms of acute TMA, including patients diagnosed with TTP or hemolytic-uremic syndrome (HUS). The overall prevalence of FVL was 8.2% (6.25% among patients diagnosed with TTP, and 9% among those with HUS) concordant with the FVL prevalence reported in Europe. FVL was present in 9.9% of patients with ADAMTS13 activity <10% and in 9.7% of those with normal ADAMTS13 activity (>50%). We conclude that FVL is not more prevalent inTMA patients without as compared to those with severe ADAMTS13 deficiency. The prevalence of FVL carriers in certain HUS subgroups (HUS with ADAMTS13 activity >50%) reaching 12.3% suggests that a contributory role of FVL in the pathogenesis of defined forms of HUS needs further study.
Molecular weight determines the frequency of delayed type hypersensitivity reactions to heparin and synthetic oligosaccharides
Authors: Alban Susanne , Kaufmann Roland , Lindhoff-Last Edelgard , Boehncke Wolf-Henning , Ludwig Ralf J. , Schindewolf Marc 
Published: November 2005

SummaryEczematous lesions, resulting from type IV sensitizations are well-known and relatively frequent cutaneous adverse effects of s.c. heparin therapy. If anticoagulation is further required intravenous heparin, heparinoids or lepirudin may be used as a substitute. However, these alternatives are not optimal in terms of practicability and/or safety-profiles. As molecular weight of different heparin preparations has repetitively been implied to determine the frequency of sensitization, we hypothesized, that due to its low molecular weight the pentasaccharide fondaparinux may provide a practicable and safe anticoagulant therapy in patients with delayed type hypersensitivity reactions (DTH) to heparin and other oligosaccharides. To test this concept, patients referred for diagnosis of cutaneous reactions after s.c. anticoagulant treatment underwent a series of in vivo skin allergyand challenge-tests with unfractionated heparin, a series of low molecular weight heparins (nadroparin, dalteparin, tinzaparin, enoxaparin and certoparin), the heparinoid danaparoid and the synthetic pentasaccharide fondaparinux. In total, data from twelve patients was evaluated. In accordance with previously published data, we report a high crossreactivity among heparins and heparinoids. In contrast – and in support of our initial hypothesis – sensitization towards the synthetic pentasaccharide fondaparinux was rarely observed. Plotting the cumulative incidence against the determined molecular weight of the individual anticoagulant preparations, shows that molecular weight generally is a key determinant of sensitization towards heparins and other oligosaccharides (r2=0.842, p=0.009). Hence, fondaparinux may be used as a therapeutic alternative in patients with cutaneous DTH relations towards heparin and other polysaccharides.
Pharmacodynamic markers in the early clinical assessment of otamixaban, a direct factor Xa inhibitor
Authors: Ozoux Marie-Laure , Chu Valeria , Simcox Kelly , Marks Vanessa , Freyburger Geneviève , Sibille Michel , Paccaly Anne , Shukla Umesh 
Published: November 2005

SummaryThis manuscript reports the assessment of pharmacodynamic (PD) markers of anti-coagulation in the first-in-man study with the novel direct Factor Xa (FXa) inhibitor, otamixaban, with a brief description of safety and pharmacokinetic (PK) findings. The study comprised ten consecutive parallel groups of healthy male subjects (6 active, 2 placebo per group). Eight groups received escalating intravenous doses of otamixaban as 6-hour infusions (1.7 to 183 μg/kg/h) and two groups received a bolus dose (30 or 120 μg/kg) with a 6-hour infusion (60 or 140 μg/ kg/h, respectively). PD markers included anti-FXa activity and clotting time measurements, i.e. activated Thromboplastin Time (aPTT), ProthrombinTime (PT), Heptest® ClottingTime (HCT), and Russell’s Viper Venom-induced clotting Time (RVVT). In addition, Endogenous Thrombin Potential (ETP) was assessed in the bolus-plus-infusion dose groups. Otamixaban was well tolerated. Otamixaban plasma concentrations increased with escalating dose, were maximal at the end-of-infusion (Ceoi), and decreased rapidly as the infusion was stopped. Anti-FXa activity coincided with otamixaban plasma concentrations and clotting time measurements followed the same pattern. Maximal changes from baseline at Ceoi were 1.9 ± 0.2 for aPTT, 2.0 ± 0.2 for PT, 5.1 ± 0.6 for HCT, and 4.5 ± 1.2 for RVVT. Otamixaban inhibited thrombin generation (24% decrease in ETP) and a delay in thrombin generation was noticed in vitro at high concentrations.