bluuebunny/crossref_metadata_2025_split huggingface dataset:
Drotrecogin alfa (activated) (recombinant human activated protein C) reduces host coagulopathy response in patients with severe sepsis
Authors: Yan S. , Margolis Benjamin , Lorente José , Russell James , Freebairn Ross , Spapen Herbert , Riess Hanno , Basson Bruce , Johnson III Gerald , Kinasewitz Gary , Dhainaut Jean-François ,   for the PROWESS Sepsis Study Group
Published: September 2003

SummaryDrotrecogin alfa (activated) improved survival in patients with severe sepsis in PROWESS, a double-blind, study of 1690 adult patients randomized to drotrecogin alfa (activated) at 24 μg/kg/h (N=850) or placebo (N=840) infused for 96 hours. Pharmacodynamic effects of drotrecogin alfa (activated) were assessed with 15 prospectively defined systemic biomarkers of hemostasis, inflammation and endothelial injury. The last-observation-carried-forward (LOCF) method of imputation for missing observations was the prospectively defined statistical method. The results were also analyzed with only the observed values without imputation for missing data (repeated measures analysis). With both statistical methods, drotrecogin alfa (activated)-treated patients demonstrated antithrombotic (reduced markers of thrombin generation and accelerated normalization of anticoagulant factor, protein C and fibrinolytic factors) and anticoagulant (prolonged PT and APTT) effects compared with placebo. A profibrinolytic (reduction in plasminogen activator inhibitor-1) effect was significant only with the LOCF imputation method in observed case and percent change from baseline analyses. An anti-inflammatory (reduction in interleukin-6) effect was significant only with the LOCF imputation method in change from baseline and percent change from baseline analyses. Drotrecogin alfa (activated) is a new and promising agent for treatment of patients with severe sepsis. The extensive analysis of systemic biomarkers confirms the previously published antithrombotic effects. However, the present results using different statistical methods do not provide a strong basis for systemic anti-inflammatory or pro-fibrinolytic effects. These latter two effects may occur at the local or cellular level. The systemic biomarkers reported here might not be the most appropriate approach to demonstrate these potential effects of drotrecogin alfa (activated).
Shedding of active tissue factor by aortic smooth muscle cells (SMCs) undergoing apoptosis
Authors: Brisset Anne-Cécile , Terrisse Anne-Dominique , Dupouy Dominique , Tellier Lise , Pech Stéphane , Navarro Chantal , Sié Pierre 
Published: September 2003

SummaryAs apoptosis of neo-intimal SMCs is a feature of advanced atherosclerotic plaques, the procoagulant properties of SMCs of synthetic phenotype undergoing apoptosis were investigated. SMCs isolated from rat aorta obtained 10 days after balloon injury, previously found to up-regulate Tissue Factor (TF) and Tissue Factor Inhibitor (TFPI) and to release large amounts of TFPI (Ghrib et al. Thromb Haemost 2002;87:1043-50), were sensitive to the apoptosis induced by Fas-ligand. During this process, surface TF activity rose by a factor 10 over 6 hours, in parallel with a proportional increase in prothrombinase, while TF protein expressed at the membrane significantly decreased. The microparticles (MPs) produced during SMC death bore intact and functional TF, but the release of TFPI did not change, so that the balance shifted to a procoagulant state during apoptosis. Shed MPs enhanced thrombus formation in flowing whole blood over collagen coated-glass slides. Apoptotic SMCs in atherosclerotic plaques represent a reservoir of highly thrombogenic material, released into the blood stream in case of spontaneous or mechanical plaque disruption.
Patterns of use of heparins in ACS
Authors: Kraxner Wilfried , Hödl Ronald , Gabriel Steg Philippe , Budaj Andrzej , Gulba Dietrich , Sadiq Immad , Van de Werf Frans , White Kami , Fox Keith , Klein Werner ,   for the GRACE Investigators
Published: September 2003

SummaryA systematic study that compares the patterns of use of unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) in patients with acute coronary syndromes (ACS) has, to date, not been carried out in the “real-world” setting. The aim of this report is to identify patterns of use of UFH and LMWH and to report their correlates and outcomes in a broad spectrum of ACS patients enrolled in the observational Global Registry of Acute Coronary Events (GRACE).The use of LMWH and UFH was analysed in 13,231 ACS patients according to patient history, concomitant treatment and invasive procedures in US and non-US sites. Frequency of use in hospitals with and without facilities for percutaneous coronary interventions (PCI) was investigated, and outcomes were analysed.Results show that younger patients (<60 years), those receiving antiplatelet therapies, thrombolytics, beta-blockers, angiotensin-converting enzyme inhibitors, patients admitted to hospitals with PCI facilities, and patients undergoing invasive procedures were more likely to receive UFH, or both UFH and LMWH than LMWH alone (80.1% enoxaparin, 19.9% other LMWH). LMWH was used less often in US than non-US sites. After adjusting for confounding variables, patients receiving LMWH had significantly lower rates of hospital mortality (P=0.009) and major bleeding (P<0.0001). Similar results were observed in patients with ST-segment elevation myocardial infarction and non-ST-segment elevation myocardial infarction or unstable angina.We can conclude that UFH tends to be used more frequently than LMWH, but hospital outcomes appeared to be better with LMWH after adjusting for covariables.
The antiaggregating activity of clopidogrel is not affected by N-acetyl L-cysteine
Authors: Lalé Alain , Savi Pierre , Herbert Jean-Marc 
Published: September 2003

SummaryN-acetyl L-cysteine (NAC) is widely used to treat obstructive bronchopulmonary diseases. It has thiol reactive properties, accounting for its mucolytic activity. Clopidogrel is a potent antithrombotic compound, metabolised by the liver which generates an active metabolite containing a thiol reactive group, responsible for an irreversible interaction with the platelet P2Y12ADP receptor.The aim of this study was to determine if NAC interferes with the antiaggregating activity of clopidogrel. For this purpose, NAC (100 µM) was incubated with platelets from rats treated or not with clopidogrel (5 mg/kg, PO, -2 h). Clopidogrel treatment strongly inhibited aggregation but this effect was not modified by NAC. In another experiment, a low concentration of the active metabolite of clopidogrel (0.3 µg/ml) was incubated with platelets from men or rats, in the absence or presence of NAC (100 µM). When stimulated by ADP (2.5 µM), platelet aggregation was inhibited by the active metabolite when incubated alone. In the presence of NAC, the inhibition by the active metabolite was not modified, therefore clearly indicating that NAC cannot reduce the thiol reactive part of the active metabolite of clopidogrel and does not interfere with its anti-aggregating activity. Moreover, in rats treated for 5 days with NAC (150 mg/kg), the activity of clopidogrel (5 or 10 mg/kg) against ADP-induced platelet aggregation was neither inhibited nor increased. This demonstrates that the generation of the active metabolite of clopidogrel is not affected by NAC.In conclusion, we have found that NAC does not restore the “normal” properties of P2Y12on platelets from clopidogrel-treated animals, it does not interfere with the antiaggregating activity of the active metabolite of clopidogrel, and does not interfere with the generation of the active metabolite.
Comparison of PFA-100 testing and bleeding time for detecting platelet hypofunction and von Willebrand disease in clinical practice
Authors: Posan Emoke , McBane Robert , Grill Diane , Motsko Cheri , Nichols William 
Published: September 2003

SummaryThe PFA-100 instrument (Platelet Function Analyzer, Dade Behring) has been reported to be superior to the bleeding time (BT) as a screening test of primary hemostasis. However evaluation of this device has been principally limited to selected populations.The study’s aim was to determine testing performance in clinical practice, by comparing the PFA-100 to the BT for the identification of von Willebrand disease (VWD) and intrinsic platelet hypofunction.From 1998-2000, PFA-100 closure time (CT) for epinephrine-collagen (EPI) and ADP-collagen (ADP) cartridges and modified Ivy BTs were performed on outpatients referred for testing for suspected or known hemorrhagic diathesis (n=346). Evaluation included assays of von Willebrand factor and platelet aggregometry in addition to platelet flow cytometry and electron microscopy when indicated. The normal distribution of PFA-100 CTs was determined using blood samples from 61 normal donors studied on 155 occasions.Results show that thirty-four patients met the diagnostic criteria for VWD and 31 patients were diagnosed with congenital or acquired intrinsic platelet hypofunction. The sensitivity of the PFA-100 for identification of VWD was significantly better (p<0.01) than the BT with similar specificity. In contrast, the PFA-100 was comparable, but not superior to the BT for detecting platelet hypofunction.We conclude that the PFA-100 performance compares favor-ably to the BT for the identification of intrinsic platelet hypofunction in clinical practice with superior sensitivity for detecting VWD.Therefore, the PFA-100 could replace the BT for purposes of screening for VWD and intrinsic platelet hypofunction. When clinical suspicion is strong, testing should be supplemented with assays of von Willebrand factor and platelet aggregometry.
Regulation of human factor IX expression using doxycycline-inducible gene expression system
Authors: Wang Xiaomin , Siemetzki Ulrike , Albert Thilo , Oldenburg Johannes , Hanfland Peter , Poller Wolfgang , Brackmann Hans-Hermann , Srour Mahmoud , Fechner Henry , Schwaab Rainer 
Published: September 2003

SummaryFollowing substitution therapy with human factor IX (hFIX) concentrate, therapy of haemophilia B by viral gene transfer has become an attractive alternative therapy in recent years. However, high doses of expressed hFIX, which can already be achieved in animal studies, may cause thrombosis in humans (van Hylckama Vlieg et al., 2000). Thus, it should be possible to maintain transgene expression within the therapeutic range. Therefore, we inserted elements of the tetracycline (Tet)-dependent Tet-On gene regulatory system into replication deficient adenovectors. The new system consists of two adenovec-tors: a response vector expressing hFIX (Ad5. TRE.hFIX), and a regulator vector expressing a second generation reverse tetracycline transactivator controlled by a CMV- (Ad5. CMV.rtTA) or human alpha1-antitrypsin-promoter (Ad5.hAAT.rtTA). Expression studies in four human cell lines showed high expression of hFIX from Ad5. TRE.hFIX in all cell lines in combination with Ad5. CMV.rtTA regulator vector, but only high specific expression in HepG2-cells in combination with Ad5.hAAT.rtTA regulator vector. Additionally, up- and down-regulation of hFIX expression could be demonstrated in vitro with the Ad5. TRE.hFIX/Ad5. CMV.rtTA combination and modulating doxycycline concentrations. When SCID-mice were infected with the Ad5. TRE.hFIX/Ad5. CMV.rtTA combination, up- and down-regulation of hFIX expression was achieved by oral doses of doxycycline for a period of at least two months. Replacement of the Ad5. CMV.rtTA vector by the Ad5.hAAT.rtTA vector showed minimal expression of hFIX in vivo. Although hFIX expression showed a slow and gradual decrease over time in vivo with the Ad5. CMV.rtTA vector, it remained within the therapeutic range. To date, regulation of hFIX has not been described in this way.
Thrombin generation in severe haemophilia A and B: the endogenous thrombin potential in platelet-rich plasma
Authors: Siegemund Thomas , Siegemund Annelie , Scholz Ute , Engelmann Lothar , Petros Sirak 
Published: September 2003

SummaryThrombin generation was investigated in platelet-rich plasma (PRP) from 11 healthy controls, 17 patients with severe haemophilia A and 7 patients with severe haemophilia B. Mean endogenous thrombin potential (ETP) in arbitrary fluorescence units (FU) was 226.9 ± 44.6, 186.4 ± 22.5, 154.2 ± 41.3 in controls, haemophilia A and B, respectively, all at a platelet count of 200 × 109/l (p = 0.004 for controls vs.haemophilia A, p = 0.003 for controls vs. haemophilia B, no significant difference between haemophilia A and B). The contribution of FVIII to thrombin generation in haemophilia A was 1.31 ± 0.16 FU/% of FVIII:C activity , while for FIX in haemophilia B this was 0.80 ± 0.21 FU/% of FIX activity. There was an almost linear relationship between increasing platelet count and thrombin generation up to a mean platelet count of 100 × 109/l. Further increase in platelet count has only a marginal influence on thrombin generation. Platelets increase ETP in haemophilia A by 0.184 ± 0.022 FU/109platelets/l and in haemophilia B by 0.319 ±
0.085 FU/109platelets/l, and this was significantly different between the two groups (p = 0.0002). This influence of platelets diminishes with increasing concentration of either FVIII or FIX. In conclusion, there is a difference in thrombin generation between haemophilia A and B, and this may be attributed to the role of platelets in the assembly of the tenase complex on their surface.
Frequency of the TAFI –438 G/A and factor XIIIA Val34Leu polymorphisms in patients with objectively proven pulmonary embolism
Authors: Zidane Majida , de Visser Marieke , ten Wolde Marije , L.Vos Hans , de Monyé Wouter , Bertina Rogier , Huisman Menno ,   the Antelope study group
Published: September 2003

SummaryDeep vein thrombosis (DVT) and pulmonary embolism (PE) are considered to be two forms of the same disease, however it is not fully understood what determines their clinical presentation.Proteins encoded by the FXIIIA and TAFI genes are involved in stabilizing the fibrin clot and in making it more lysis resistant. The FXIIIA 34Leu and TAFI –438A alleles might protect against DVT. Information on such an association with PE is either contradictory or missing. We hypothesized that both polymorphisms might influence the formation and fate of emboli and accordingly the risk of PE. We determined the frequencies of both polymorphisms in patients with objectively demonstrated PE.The frequency of FXIIIA Leu34Leu in PE patients and non-PE patients was 4.5% and 8.8%, [OR 0.5 (95% CI: 0.1 to 1.9)], respectively. For –438 A/A TAFI genotype the frequency was 1.5% and 8.1% [OR 0.1 (95% CI: 0.02 to 1.1)], respectively.
Induction of plasminogen activator inhibitor 1 by the PPARα ligand, Wy-14,643, is dependent on ERK1/2 signaling pathway
Authors: Banfi Cristina , Auwerx Johan , Poma Federica , Tremoli Elena , Mussoni Luciana 
Published: September 2003

SummaryImpairment of the fibrinolytic system, mostly due to elevated plasma levels of plasminogen activator inhibitor 1 (PAI-1), is often associated with metabolic disorders such as diabetes mellitus and insulin-resistance syndrome. Moreover, insulin, as we have previously shown, directly stimulates PAI-1 production with a mechanism underlying a complex signaling network which ultimately leads to ERK activation.In this study we have analyzed the effects of agonists of the per-oxisome proliferator-activated receptor (PPAR) alpha and gamma on PAI-1 biosynthesis in HepG2 cells in the presence or absence of insulin. The high affinity PPARα agonist, Wy-14,643, increased basal and insulin-stimulated PAI-1 antigen release with a mechanism involving gene transcription. We then investigated whether the MAP kinase pathway also plays a role in the stimulatory properties of Wy-L4,643. Wy-L4,643 increases phosphorylation of ERK and p38 in a time-dependent manner without affecting that of SAPK/JNK or ERK5. Moreover, the MEK (ERK kinase) inhibitors, PD98059 and UO126, completely prevented PAI-1 induction by Wy-14,643 without inhibiting the activation of a reporter gene carrying the PPRE element. Interestingly, the addition of p38 inhibitor followed by insulin and Wy-14,643 resulted in a greater than additive stimulation of PAI-1 secretion acting through ERK1/2 phosphorylation.In contrast, the synthetic PPARγ agonist, rosiglitazone, did not change PAI-1 level, although this compound induced transcription from the PPRE-driven luciferase reporter construct.In conclusion, Wy-14,643 induces PAI-1 gene expression, in the presence or absence of insulin, with a mechanism which is independent on PPARα activation and requires signaling through the ERK1/2 signaling pathway.
High prevalence of elevated clotting factor VIII in chronic thromboembolic pulmonary hypertension
Authors: Bonderman Diana , Turecek Peter , Jakowitsch Johannes , Weltermann Ansgar , Adlbrecht Christopher , Schneider Barbara , Kneussl Meinhard , Rubin Lewis , Kyrle Paul , Klepetko Walter , Maurer Gerald , Lang Irene 
Published: September 2003

SummaryChronic thromboembolic pulmonary hypertension (CTEPH) is an enigmatic disorder lacking signs, symptoms and classical risk factors for venous thromboembolism.The objective of the prospective case controlled study, carried out at the Pulmonary Hypertension Unit, University Hospital Vienna, Austria, was to investigate whether plasma FVIII is elevated in CTEPH patients.The study examined 122 consecutive patients diagnosed with CTEPH. Plasma FVIII was measured and compared with plasma FVIII of healthy controls (n=82) and of patients with non-thromboembolic pulmonary arterial hypertension (PAH, n=88).Results show that CTEPH patients had higher FVIII levels than controls (233±83IU/dl versus 123±40IU/dl, p<0.0001) and PAH patients (158±61IU/dl, p<0.0001). Plasma FVIII one year after surgery (212±94IU/dl) was statistically unchanged compared with preoperative values (FVIII: 226±88IU/dl, n=25). FVIII>230IU/dl was more prevalent in CTEPH patients (41%) than in controls (5%, p<0.0001) and PAH patients (22%, p=0.022).We can conclude that elevated plasma FVIII is the first prothrombotic factor identified in a large proportion of CTEPH patients.
Platelet factor 4 localization in carotid atherosclerotic plaques: correlation with clinical parameters
Authors: Pitsilos Stephanie , Hunt Jennifer , Mohler Emile , Prabhakar Anand , Poncz Mortimer , Dawicki Jennine , Khalapyan Tigran , L.Wolfe Megan , Fairman Ronald , Mitchell Marc , Carpenter Jeffrey , Golden Michael , Cines Douglas , Sachais Bruce 
Published: September 2003

SummaryEmerging evidence supports a role for platelets in the progression of atherosclerosis in addition to an involvement in thrombotic vascular occlusion. Platelet Factor 4 (PF4), a chemokine released by activated platelets, stimulates several pro-atherogenic processes. Therefore, we examined the localization of PF4 and the homologous protein, Neutrophil Activating Protein-2 (NAP-2) in lesions representing the evolution of human atherosclerotic plaques. Carotid plaques from 132 patients with critical carotid stenosis and 6 autopsy specimens were studied. Clinical, histologic and immunohistochemical data were analyzed using a χ2-test. PF4 was detected in the cytoplasm of luminal and neovascular endothelium, in macrophages and in regions of plaque calcification. The presence of PF4 in macrophages and neovascular endothelium correlated with lesion grade (p = 0.004; p = 0.044). Staining of macrophages for PF4 correlated with the presence of symptomatic atherosclerotic disease (p = 0.028). In early lesions, PF4 was commonly found in macrophages of early lesions (Grade I/II), whereas NAP-2 was rarely present.In conclusion, correlation between PF4 deposition, lesion severity and symptomatic atherosclerosis suggests that persistent platelet activation may contribute to the evolution of athero-sclerotic vascular lesions. These studies support the rationale for the chronic use of anti-platelet therapy in patients at risk for developing symptomatic atherosclerosis.
Matrix metalloproteinase-9 expression in post-hypoxic human brain capillary endothelial cells: H2O2 as a trigger and NF-κB as a signal transducer
Authors: Kolev Krasimir , Skopál Judit , Simon László , Csonka Éva , Nagy Zoltán , Machovich Raymund 
Published: September 2003

SummaryThe haemorrhagic transformation in ischemic stroke involves disruption of the integrity of the microvascular beds, partially based on the action of matrix metalloproteinases (MMPs). The objective of the present study was to evaluate the contribution of microvascular endothelial cells from human brain (HBECs) to MMPs’ expression and regulation under conditions relevant to brain ischemia. MMPs and their inhibitors were examined with zymography, Western-blotting, ELISA and MMP-activity assay in cultured HBECs. Four-hour hypoxia (pO2=60 mmHg) elevated the level of MMP-9 in the supernatant of the HBECs and this early response required collagen-matrix. Active oxygen species sustained the increased MMP-9 activity for at least 24 h. In the post-hypoxic period 20 μmol/L H2O2 caused a 6-fold increase in the specific activity of MMP-9 over the nor-moxic cells and a comparable effect was exerted by thrombin (50 nmol/L) and leukocyte elastase (10 nmol/L). The role of NF-κB, a redox-state sensitive transcription factor, was evaluated with immunofluorescence confocal microscopy and immunoblotting of nuclear and cytoplasmic extracts. The oxidative stress-dependent MMP-9 induction was accompanied by a significant increase in the NF-κB localized in the nuclei and these responses were blunted with a proteasome inhibitor (MG132). Consequently, according to our in vitro data HBECs are a source of MMP-9, which is under the control of triggers relevant to the ischemic/reperfused brain (reactive oxygen species, thrombus and inflammation related proteases) and this regulation is partially based on NF-κB activation. The reported regulation of endothelium-derived MMP-9 supports its potential involvement in the post-hypoxic disturbances of the cerebral micro-circulation.
A tetrameric glycoprotein Ib-binding protein, agglucetin, from Formosan pit viper: structure and interaction with human platelets
Authors: Wang Wen-Jeng , Ling Qing-Dong , Liau Ming-Yi , Huang Tur-Fu 
Published: September 2003

SummaryAgglucetin, a tetrameric agglutination inducer from the Formosan pit viper, has been identified as a platelet membrane glycoprotein (GP) Ib agonist and directly agglutinated fixed-platelets in the absence of von Willebrand factor (vWf). Here, we resolved the complete cDNA sequences of agglucetin subunits (α1, α2, β1 and β2) by molecular cloning. Each cloned cDNA encoding the leader peptide (23 residues) and the mature subunit (131/135/123/126 residues) shares a high degree of homology to each other and the C-type lectin-like GP Ib-binding proteins (BPs). Furthermore, agglucetin specifically caused platelet agglutination and surface exposure of integrin αIIbβ3 with a GPIb-dependent manner in washed platelets, based on the observation that the enhanced expression of functional αIIbβ3 was suppressed by a GPIb-cleaving metalloproteinase, crotalin. Pretreating platelets with staurosporine or BAPTA-AM also completely blocked the exposure of functional αIIbβ3, suggesting that the activation of protein kinase C and intracellular calcium mobilization are involved in the GPIb-dependent signaling. In human platelet-rich plasma (PRP), agglucetin elicited sequential biphasic responses of platelet agglutination and aggregation in a GPIb- and αIIbβ3-dependent manner, respectively, implying that other cofactors may amplify platelet activation to trigger aggregation.The nucleotide sequences reported in Figs. 1 and 2 have deposited in the GenBank, EMBL and DDBJ Nucleotide Sequence Databases under the accession numbers: AF540645 for agglucetin-α1 subunit, AF540646 for agglucetin-α2 subunit, AF540647 for agglucetin-β1 subunit and AF540648 for agglucetin-β2 subunit.