bluuebunny/crossref_metadata_2025_split huggingface dataset:
GPV Is a Marker of
In Vivo
Platelet Activation – Study in a Rat Thrombosis Model
Authors: Freund Monique , Mangin Pierre , Azorsa David O. , Schwartz Catherine , Moog Sylvie , Schuhler Simone , Dambach Josiane , Cazenave Jean-Pierre , Lanza François , Ravanat Catherine 
Published: March 2018

SummaryThrombin plays a central role in the genesis of thrombotic events and is the most potent known platelet agonist. This enzyme activates platelets by cleaving G-protein coupled protease activated receptors (PARs) and by binding to glycoprotein (GP) Ib. Thrombin also cleaves platelet GPV to liberate a soluble 69 kDa fragment (GPVf1), leaving a 20 kDa fragment (GPVf2) attached to the membrane. The aim of this study was to assess the value of GPV as an in vivo marker of the activation of platelets by thrombin. Newly developed monoclonal and polyclonal antibodies recognizing rat GPVf1 and GPVf2 respectively were used to detect soluble GPV by ELISA and the new NH2-terminus exposed by thrombin using flow cytometry. These assays were employed in a rat thrombosis model designed to trigger thrombin formation in vivo. When thromboplastin (4.8 ml/kg/h) was infused for 30 min, thrombin generation was reflected by a rapid increase in thrombin-antithrombin (TAT) complexes in plasma and by the appearance of GPVf2 at the surface of circulating platelets. Simultaneously, GPVf1 disappeared from the surface of platelets and accumulated as a soluble fragment in plasma, where it was detected by GPV ELISA. These effects were inhibited by pretreatment of the rats with hirudin. Levels of plasma PF4 also increased in this model, but unlike GPV levels which returned slowly (> 2 hours) to baseline, PF4 had a very short half-life.In conclusion, GPV is cleaved by thrombin in vivo, circulates and is a reliable in vivo marker of the activation of platelets by thrombin. Monitoring of GPV levels in rats should be useful to evaluate the effects of antithrombotic and antiplatelet drugs, while further studies will be required to confirm the potential interest of GPV as a marker of thrombotic states in humans.
Protamine Sulphate Inhibits Platelet Membrane Glycoprotein Ib-von Willebrand Factor Activity
Authors: Stephens Ross , Hamers Maria , Sakariassen Kjell , Barstad R. 
Published: March 2018

SummaryPlatelet adhesion to the injured vessel wall is essential in haemostasis and thrombosis. This process involves the interaction of the platelet glycoprotein Ib (GPIb) with surface bound von Willebrand factor (vWF). Since synthetic polycationic peptides of the general formula (Arg)n, (Lys)n or (Arg-Lys)n inhibit GPIb-vWF interaction, they were suggested as potential antithrombotics. Protamine sulphate is a highly cationic polypeptide, arginine accounting for approximately 60% of the primary sequence, utilized to neutralize the anticoagulant effect of heparin after cardiac surgery. We have investigated potential effects of protamine sulphate on the function of GPIb-vWF.Addition of protamine sulphate to platelet-rich plasma (PRP), reduced significantly the GPIb-vWF activity as assessed by ristocetininduced platelet agglutination. When protamine sulphate was added to PRP containing heparin, even at clinically relevant neutralizing doses the GPIb-vWF activity was reduced by 20-30 % (p < 0.001). Protamine sulphate in excess of heparin nearly abolished the activity. Furthermore, the direct effect of protamine sulphate on collagen-induced platelet thrombus formation in non-anticoagulated human blood was investigated by employing an ex-vivo parallel-plate perfusion chamber device. Protamine sulphate (200 µg/mL) reduced platelet-collagen adhesion at shear rates of 650 and 2600 sec−1 by 40% (p < 0.004) and 45% (p < 0.0001), respectively. The corresponding platelet thrombus volumes were concomitantly reduced by 90% (p < 0.006) and 84% (p < 0.05).Our data are questioning the rationale for empirical repetitive protamine sulphate administration when so-called “heparin rebound” after cardiac surgery is suspected, since protamine sulphate in excess of heparin may impair the platelet GPIb-vWF interaction necessary for normal haemostasis.
A Comparative, Double-blind, Randomised Trial of a New Second Generation LMWH (Bemiparin) and UFH in the Prevention of Post-operative Venous Thromboembolism
Authors: Howes J. , Sharma V. , Kadziola Z. , Kakkar V. V. ,   the Bemiparin Assessment group
Published: March 2018

SummaryA randomised, prospective, double-blind trial was performed, to compare the safety and efficacy of a new low-molecular-weight heparin (LMWH) Bemiparin and standard unfractionated heparin (UFH), for the prophylaxis of postoperative venous thromboembolism. 300 patients scheduled to undergo elective hip arthroplasty were included. The principal outcome measures were the incidence of thromboembolic events and bleeding complications. 149 patients received 3,500 anti-Xa IU of bemiparin plus a placebo injection daily and 149 patients received 5,000 IU of UFH twice a day.The two groups were similar with respect to factors likely to affect the risk of developing post-operative venous thromboembolism (VTE) and risk of bleeding events. During the post-operative period, 34 patients developed VTE complications; 9 (7.2%) in the bemiparin group and 25 (18.7%) in the UFH group. VTE in the two groups was statistically significant (OR of 2.96; 95% CI 1.32-6.62 and p = 0.01).There were no significant differences in the frequency of bleeding complications: major bleeding requiring discontinuation of prophylaxis, (OR 1.21; 95% CI 0.36-4.05; p = 1.00), the measured median operative blood loss (p = 0.77) or the median postoperative drain loss (p = 0.97), and the number of patients who developed wound haematoma (OR 0.87; 95% CI 0.31-2.46; p = 1.00).A comparison of coagulation parameters on the preoperative day with post-operative day 2 ± 1, day 6 ± 1 and day of discharge showed a significantly higher AT concentration, anti-factor Xa activity and TFPI levels in the bemiparin group when compared with UFH.This study demonstrates that bemiparin, in a single daily subcutaneous dose of 3,500 anti-Xa IU in high risk patients undergoing hip arthroplasty is more effective than UFH administered twice daily at a dose of 5,000 IU in the prevention of postoperative VTE. Both agents are equally safe.List of participants, their affiliations and current addresses are listed in the appendix on p. 528
Intermediate and Severe Hyperhomocysteinemia with Thrombosis: A Study of Genetic Determinants
Authors: Gaustadnes Mette , Rüdiger Niels , Rasmussen Karsten , Ingerslev Jørgen 
Published: March 2018

SummaryHyperhomocysteinemia is an independent risk factor for cardiovascular disease. In search of genetic factors causing elevated levels of total homocysteine in plasma (tHcy), we investigated a cohort of consecutively identified, unrelated thrombosis patients (n = 28) having intermediate or severe hyperhomocysteinemia (30 µmol/l<tHcy ≤100 µmol/l, and tHcy >100 µmol/l, respectively). The methylenetetrahydrofolate reductase (MTHFR) 677C→T genotype, and the complete cystathionine β-synthase (CBS) genotype was determined in all patients. We found that the MTHFR T/T genotype was strongly correlated with intermediate hyperhomocysteinemia, being present in 73.9 % of those cases (17 of 23). In three of five patients with severe hyperhomocysteinemia, compound heterozygosity for CBS mutations was detected. Among the mutations, two novel missense mutations: 1265C→T (S422L) and 1397C→T (S466L) were detected. The phenotype in those patients was quite mild, thromboembolism apart. This indicates that a search for CBS mutations in patients with severe hyperhomocysteinemia is important to ensure the detection of a possible CBS deficiency, thus enabling treatment. Co-existence of the MTHFR T/T genotype and the common CBS 844ins68 variant was significantly higher among patients (10.7%) as compared to controls (1.2%), indicating that this genotype combination is a thrombotic risk factor (P <0.05). In a few patients, hyperhomocysteinemia could not be explained by this genetic approach, suggesting that other genetic risk factors were implicated.Abbreviations: MTHFR, methylenetetrahydrofolate reductase; CBS, cystathionine β-synthase; tHcy, total homocysteine in plasma.
Enhanced Tissue Factor Pathway Activity and Fibrin Turnover in the Alveolar Compartment of Patients with Interstitial Lung Disease
Authors: Günther A. , Mosavi P. , Ruppert C. , Heinemann S. , Temmesfeld B. , Velcovsky H. G. , Morr H. , Grimminger F. , Walmrath D. , Seeger W. 
Published: March 2018

SummaryBronchoalveolar lavage fluids (BALF) from patients with hyper- sensitivity pneumonitis (HP; n = 35), idiopathic pulmonary fibrosis (IPF, n = 41) and sarcoidosis (SARC, n = 48) were investigated for alterations in the alveolar hemostatic balance. Healthy individuals (n = 21) served as Controls. Procoagulant activity (PCA), tissue factor (TF) activity and F VII activity were assessed by means of specific recalcification assays. The overall fibrinolytic activity (FA) was measured using the 125I-labeled fibrin plate assay. Fibrinopeptide A (FP-A), D-Dimer, plasminogen activators (PA) of the urokinase (u-PA) or tissue type (t-PA), PA-Inhibitor I (PAI-1) and α2-antiplasmin (α2-AP) were determined by ELISA technique. As compared to Controls, all groups with interstitial lung disease (ILD) displayed an increase in BALF PCA by approximately one order of magnitude, and this was ascribed to enhanced TF activity by >98%. Accordingly, F VII-activity was increased in all ILD groups, and elevated FP-A levels were noted. There was no significant difference in procoagulant activi- ties between the different ILD entities, but the increase in TF was significantly correlated with deterioration of lung compliance. Overall fibrinolytic activity did not significantly differ between ILD entities and Controls, although some reduction in IPF subjects was observed. Nevertheless, changes in the profile of the different pro- and anti- fibrinolytic compounds were noted. U-PA, but not t-PA levels were significantly reduced in all ILD groups. α2-AP was markedly elevated throughout, whereas PAI-1 levels were lowered. As a balance of enhanced procoagulant and sustained overall fibrinolytic activity, lavage D-dimer levels were elevated by more than one order of magnitude in all ILD patients. We conclude that the predominant alteration in alveolar hemostatic balance in all groups of ILD patients is an enhancement in TF factor pathway activity. Concomitantly, various compounds of the (anti-)fibrinolytic pathways present with altered concentrations, but the overall BALF fibrinolytic activity is largely unchanged. The net enhancement of fibrin turnover is significantly correlated with the decrease in lung compliance.
Abbreviations: α2-AP – α2-antiplasmin; ARDS – acute respiratory distress syndrome; BAL – bronchoalveolar lavage; BALF – BAL fluids; BSA – bovine serum albumin; FEV1 – forced expired volume within 1 s; FP-A – fibrinopeptide A; FVC – forced vital capacity; ILD – interstitial lung disease; IPF – idiopathic pulmonary fibrosis; HP – hypersensitivity pneumonitis; PAI-1 – plasminogen-activator-inhibitor-1; PBS – phosphate buffered saline; PCA – procoagulant activity; PL – phospholipid; PPQ – phospholipid-proteinquotient; SARC – sarcoidosis; t-PA – tissue-type plasminogen activator; u-PA – urokinase-type plasminogen activator
Nomograms for the Administration of Unfractionated Heparin in the Initial Treatment of Acute Thromboembolism – an Overview
Authors: Bernardi Enrico , Piccioli Andrea , Oliboni Giancarlo , Zuin Renzo , Girolami Antonio , Prandoni Paolo 
Published: March 2018

SummaryDespite the availability of low-molecular-weight heparins, unfractionated heparin (UFH) still remains the drug of choice for the initial treatment of acute venous thromboembolism in many countries. When appropriately employed, UFH treatment results in a degree of efficacy and safety that is fully comparable with that obtained with the use of heparin derivatives. The use of nomograms for the intravenous or subcutaneous administration of UFH assures that virtually all patients will promptly achieve adequate levels of anticoagulation, thus decreasing the likelihood of recurrent venous thromboembolism without extra bleeding-risk.In this article we reviewed clinical studies on the implementation and validation of UFH dosing nomograms, and attempted a quantitative analysis of their performance. According to the results of our analysis, a statistically significantly higher proportion of patients treated on the basis of a nomogram reached a therapeutic anticoagulant level within 24 h of treatment, as compared to patients treated following the standard practice (odds ratio, 3.6; 95% CI, 2.6 to 4.9). The rate of recurrent thromboembolic events was significantly lower for patients treated according to a nomogram (odds ratio, 0.3; 95% CI, 0.1 to 0.8), while no significant differences in terms of either major or minor bleedings were detected between nomogram patients and controls.
Ontogeny of Beta 2 Glycoprotein I and Annexin V in Villous Placenta of Normal and Antiphospholipid Syndrome Pregnancies
Authors: Kingdom John , Mackie Ian , Burrell Stephen , Quenby Siobhán , Jauniaux Eric , Machin Samuel , Donohoe Siobhán 
Published: March 2018

Summaryβ2-glycoprotein I (β2GPI) and annexin V (AV) have been implicated in the pathophysiology of the antiphospholipid syndrome (APS). We investigated their placental expression in normal villous tissues throughout gestation; first trimester n = 10, early second trimester; n = 4, preterm; n = 5) and term; n = 7 and in APS (2 first trimester, 1 preterm and 8 term deliveries). β2GPI and AV were both expressed by the placenta from as early as seven weeks gestation and were colocalised to the syncytiotrophoblast. β2GPI staining was also observed in stromal cells, being present in phagocytic Hofbauer cells and surrounding newly formed fetal vessels in a perivascular pattern, from seven to seventeen weeks gestation. An abnormal morphological distribution of AV was noted in one first trimester APS placenta, and for β2GPI in a further first trimester placenta. When placental proteins were extracted from villous tissue, the concentration of AV/mg protein in term APS placentas (median, interquartile range) (aPS; 8.16, 7.87-9.72 µg/mg) was significantly higher (p <0.005) than normal term levels (normal; 2.47, 2.28-2.54 µg/mg). β2GPI increased with advancing gestation (first trimester; 0.93, 0.64-1.26 µg/mg, term; 3.67, 2.58-4.48 µg/mg) in normal pregnancy. Term APS placentas had a reduced β2GPI content (2.31, 1.87-2.49 µg/mg), p <0.05. The placental role of these proteins remains to be identified.
Inhibition of Tissue Factor Synthesis by Disruption of ERK Kinases and PKC Signaling Pathways in Human Vascular SMCs
Authors: Xuereb J. M. , Sié P. , Boneu B. , Constans J. 
Published: March 2018

SummaryTissue Factor (TF), the receptor for plasma VII/VIIa and the initiator of blood coagulation, is inducible in vascular smooth muscle cells (SMCs) by growth factors and bacterial lysopolysaccharides (LPS) and is expressed in vivo after vascular injury. As TF expression is a determinant of the thrombogenicity of vascular lesions, we investigated the signal pathways involved in this process.Human vascular SMCs were obtained from normal arteries and made quiescent by serum deprivation. Baseline TF antigen and activity were up-regulated by various agonists: fetal calf serum (FCS), LPS, and platelet derived growth factor (PDGF) being the most effectives but with different kinetics. TF expression induced by LPS was transient with a maximum 6 h after stimulation and returned to baseline levels after 24 h whereas TF expression induced by serum or PDGF was sustained for at least 24 h. Rapid and transient activation of Extracellular signal-Regulated Kinase (ERK) was observed after stimulation by PDGF and FCS, but not by LPS. The role of ERK, Ras and protein kinase C activities were investigated using specific inhibitors, PD 98059, manumycin A and calphostin C respectively. For TF induction by LPS, PKC activity was required and the ERK/Ras pathway was not involved. In contrast, the effect of PDGF was strictly ERK and Ras dependent, but partially prevented by PKC inhibitors. TF induction by FCS was ERK dependent but partially Ras and PKC dependent. In conclusion, TF expression appears to be a non-specific response of SMCs to numerous stimuli through multiple signal pathways which differ according to the inducing agent.
Procoagulant Activity of Endothelial Cells after Infection with Respiratory Viruses
Authors: Bouwman J. J. M. , Bouter K. P. , Diepersloot R. J. A. , de Groot Ph. G. , Erkelens D. W. , Visseren F. L. J. 
Published: March 2018

SummaryInfluenza virus epidemics are associated with excess mortality due to cardiovascular diseases. There are several case reports of excessive coagulation during generalised influenza virus infection. In this study, we demonstrate the ability of respiratory viruses (influenza A, influenza B, parainfluenza-1, respiratory syncytial virus, adenovirus, cytomegalovirus) to infect lung fibroblasts and human umbilical vein endothelial cells in culture. All viral pathogens induced procoagulant activity in infected endothelial cells, as determined in a one-stage clotting assay, by causing an average 55% reduction in the clotting time. When factor VII deficient plasma was used clotting time was not reduced. The induction of procoagulant activity was associated with a 4- to 5-fold increase in the expression of tissue factor, as measured by the generation of factor Xa. Both experiments indicate that the procoagulant activity of endothelial cells in response to infection with respiratory viruses is caused by upregulation of the extrinsic pathway. Although both enveloped viruses and a non-enveloped virus (adenovirus) induced procoagulant activity in endothelial cells by stimulating tissue factor expression, the role of the viral envelope in the assembly of the prothrombinase complex remains uncertain.We conclude that both enveloped and non-enveloped respiratory viruses are capable of infecting cultured human endothelial cells and causing a shift from anticoagulant to procoagulant activity associated with the induction of tissue factor expression.
Thrombotic Thrombocytopenic Purpura: A Paradigm Shift?
Authors: Konkle Barbara , Furlan Miha , Cines Douglas 
Published: March 2018

SummaryThe pathophysiology of thrombotic thrombocytopenic purpura (TTP) has fascinated hematologists for decades. What causes seemingly healthy individuals to suddenly develop widespread platelet-rich microthrombi in specific microvascular beds while sparing other vascular sites completely? Is the disorder caused by the sudden appearance of a novel platelet-agglutinating factor or do platelet-rich thrombi form as a consequence of insult to the capillary endothelium? Is the disease self-limiting, does plasma exchange fundamentally alter the pathophysiology of an autoimmune attack on a normal endothelium, or does the immune response develop to microvasculature that has been perturbed and, if so, by what? It has been thought by many of us that the answers to these questions will provide insight into how platelet-vessel wall interactions are normally regulated in the microvasculature and the differences that characterize the behavior of microvascular, arterial and venous systems in various organs. The corollary to these scientific issues is the anticipation that such answers would also lead to new strategies for intervention in other, more common thrombotic diseases.
Insulin Sensitivity and Hemostatic Factors in Clinically Healthy 58-year-old Men
Authors: Bokemark Lena , Wikstrand John , Lindahl Anders , Fagerberg Björn , Agewall Stefan 
Published: March 2018

SummaryThe objective of this cross-sectional study was to investigate the relationship between factors of the coagulation- and fibrinolysis systems and insulin sensitivity in 104 clinically healthy, 58-years-old men. Insulin sensitivity (hyperinsulinemic euglycemic clamp) adjusted for lean body mass, the metabolic syndrome according to a suggested definition, and different factors in the coagulation- and fibrinolysis system were determined. Subjects with the metabolic syndrome were characterised by increases in PAI-1 activity, tPA antigen, protein C and protein S and low concentrations of tPA activity. Insulin sensitivity was independently and reversibly associated with PAI-1 (p = 0.014) and directly with tPA activity (p = 0.001). Insulin sensitivity was also significantly negatively associated with protein S and protein C and several components in the metabolic syndrome, however not remaining significant in multivariate analyses. Protein C and protein S were significantly associated with PAI-1 activity, tPA activity (negatively), tPA antigen and antithrombin III. In conclusion, the data indicated that insulin resistance and several of the clustering components in the metabolic syndrome are accompanied by increased plasma concentrations of the anticoagulatory proteins C and S which may represent a mechanism which counteracts the concomitantly occurring hypofibrinolysis.
Antithrombin Therapy for Severe Preeclampsia
Authors: Maki Masahiro , Terao Toshihiko , Ikenoue Tsuyomu , Satoh Kazuo , Nakabayashi Masao , Sagara Yusuke , Kajiwara Yayoi , Urata Masao , Kobayashi Takao ,   for BI51.017 Study Group
Published: March 2018

SummaryA double-blind, randomized, placebo-controlled trial was conducted to evaluate whether treatment with Antithrombin (AT) concentrates improved the clinical and perinatal outcome in patients with severe preeclampsia. Severe preeclamptic patients (24 to 35 weeks of gestation, Gestosis Index (GI) > 6 points) were randomized into two groups: 66 received AT and 67 received placebo. There were no statistical differences in the clinical profiles of the two groups. Study drugs were given intravenously once daily for 7 consecutive days. Maternal symptoms were evaluated from the difference of GI between before and after treatment, and fetal findings were evaluated from the changes of the biophysical profile score and the estimated fetal weight gain. Improvement was significantly greater in the AT group for both the GI (p = 0.020) and the estimated fetal weight gain (p = 0.029). The improvement of coagulation parameters was also evaluated. The D-dimer levels increased significantly in the placebo group (p = 0.026), but did not change in the AT group. Gestation was significantly prolonged (p = 0.007), and the number of low-birth weight infants was significantly smaller (p = 0.011) in the AT group. No adverse events related to AT were observed. It is revealed that AT concentrate therapy for preeclampsia is effective and safe, leading to an improved perinatal outcome.
Factor XIII Deficiency Causing Mutation, Ser295Arg, in Exon 7 of the Factor XIIIA Gene
Authors: Gallivan Louise , Miloszewski Krzysztof , Markham Alexander , Anwar Rashida 
Published: March 2018

SummaryInherited factor XIII (FXIII) deficiency is an autosomal recessive disorder which results in a serious bleeding diathesis, problems with wound healing and a very high risk of recurrent miscarriage in deficient females. We have analysed the molecular basis of factor XIII deficiency in two patients and their parents, who originate from the North of Pakistan. Four sequence changes were identified: an AGC→AGG (Ser→Arg) FXIII deficiency-causing mutation in codon 295; G→A at position -246 upstream of exon 1; T→C and C→T at positions -23 and -24, respectively, in intron 9. Using molecular modelling we predict that the Ser295Arg mutation would prevent the FXIIIA molecule from folding correctly and thus result in an unstable FXIIIA mutant polypeptide. The sequence changes −246G→A, −23T→C and −24C→T are normal polymorphisms. RT-PCR analysis demonstrates that the intronic sequence changes do not appear to affect the accuracy of FXIIIA RNA processing.