bluuebunny/crossref_metadata_2025_split huggingface dataset:
Risk factors and coagulation parameters in relationship to phlebographic response and clinical outcome in the treatment of acute deep vein thrombosis
Authors: Kadziola Zbigniew , Scully Mike , Nakov Roumen , Misselwitz Frank , Kakkar Vijay , Breddin Hans 
Published: March 2018

SummaryPossible correlation of the effects of pharmacotherapy on the inhibition of the in-vivo generation of thrombin and on the prevention of thrombus extension in patients with deep vein thrombosis (DVT) could help to define patients at higher risk.Patients with symptomatic deep vein thrombosis confirmed by phlebography were randomised to intravenous unfractionated heparin (UFH), or a subcutaneous low-molecular-weight heparin (reviparin) twice daily for one week, or a subcutaneous reviparin once daily for four weeks. The patients were treated with oral anticoagulants for at least 3 months. Main endpoints were regression of thrombus on phlebography on Day 21 and recurrent symptomatic venous thromboembolism up to 3 months. Coagulation parameters, markers of in-vivo thrombin generation, and TFPI-release were determined at randomisation, weeks 1 and 3.Four hundred sixty six responders (reduction of at least 30 per cent in Marder score) and 419 non-responders (Marder score unchanged or changed less than ±30%) showed no significantly different baseline characteristics. The non-responder group had a higher median Marder score at baseline and after one and three weeks of treatment, and had significantly higher fibrinogen levels, TAT complexes and F1+2 values than responders. There were no significant differences in coagulation parameters between non-responders and patients with asymptomatic + symptomatic VTE with the exception of higher TAT complexes at baseline.Significant differences in Marder score and coagulation parameters at baseline were found between responders and non-responders. Non-responders have a higher risk tosuffer recurrent VTE and may need intensified treatment.
Activation of human platelets by 2-arachidonoylglycerol is enhanced by serotonin
Authors: Bari Monica , Del Principe Domenico , Finazzi-Agrò Alessandro , Maccarrone Mauro 
Published: March 2018

SummaryThe endocannabinoid 2-arachidonoylglycerol (2-AG) has been shown to activate human platelets in platelet-rich plasma, by binding to a “platelet-type” cannabinoid receptor (CBPT). Here, washed human platelets were used to characterize the binding of [3H]2-AG to CBPT, showing a dissociation constant (Kd) of 140 ± 31 nM and a maximum binding (Bmax) of 122 ± 10 pmol.mg protein-1. Selective antagonists of both CB1 and CB2 cannabinoid receptors inhibited this binding, which was enhanced up to ~230% over the controls by 1 µM serotonin (5-hydroxytryptamine, 5-HT). Human platelets were also able to bind [3H]5-HT (Kd = 79 ± 17 nM, Bmax = 14.6 ± 1.3 pmol.mg protein-1), and 1 µM 2-AG enhanced this binding up to ~150%. Moreover, they were able to take up [3H]5-HT through a high affinity transporter (Michaelis-Menten constant = 22 ± 2 nM, maximum velocity = 344 ± 15 pmol.min-1.mg protein-1), which was not affected by 2-AG. Interestingly, 5-HT did not affect the activity of the 2-AG transporter of human platelets. Treatment of washed platelets with 1 µM 2-AG led to increased intracellular inositol-1,4,5-trisphosphate (up to ~300%) and decreased cyclic AMP (down to ~50%). Furthermore, treatment of pre-loaded platelets with 1 µM 2-AG induced a ~300% increase in [3H]2-AG release, according to a CBPT-dependent mechanism. Also, 1 µM 5-HT enhanced the effect of 2-AG on inositol-1,4,5-trisphosphate (~500% of the controls), cyclic AMP (~20%) and [3H]2-AG release (~570%), and the latter process was shown to be partly (~50%) involved in the 5-HT-dependent platelet activation. Taken together, reported findings represent the first demonstration that 2-AG and 5-HT can mutually reinforce their receptor binding on platelet surface, which might have therapeutic implications.
Fibrinolytic capacity increases with age in healthy humans, while endothelium-dependent vasodilation is unaffected
Authors: Hrafnkelsdóttir Thórdís , Wall Ulrika , Swedberg Karl , Jern Sverker , Gudnason Thorarinn 
Published: March 2018

SummaryThe capacity for stimulated endothelial release of tissue-type plasminogen activator (tPA) and endothelium-dependent vasodilation is diminished in patients with cardiovascular risk factors. We examined the effect of age on desmopressin-stimulated tPA release and endothelium-dependent vasodilation, using the perfused-forearm model. Thirty-two healthy subjects were divided into quartiles by age (mean age 24, 36, 54, and 72 years, respectively). Baseline fibrinolytic parameters, baseline forearm blood flow (FBF), and increase in stimulated FBF were all similar across age. By contrast, the capacity for desmopressin-stimulated release of tPA increased linearly by age. For tPA antigen, the total amount released (area-under-the-curve) was 1015, 1282, 2139, and 2845 ng/L tissue (p = 0.011) and the peak release rates were 62, 80, 113, and 163 ng/min/L tissue (p = 0.008) in the age-quartiles, respectively. A similar significant age-related response was observed for tPA activity. We conclude that in healthy individuals there is an up-regulation of the fibrinolytic response by age.
Human/chicken urokinase chimeras demonstrate sequences outside the serine protease domain that dictate autoactivation
Authors: Aimes Ronald , Regazzoni Karine , Quigley James 
Published: March 2018

SummaryMammalian urokinase-type plasminogen activator (uPA) is produced as a stable single polypeptide chain zymogen and requires a distinct proteolytic cleavage to become an active, two-chain enzyme. In contrast, chicken uPA, both native and recombinant, is found predominantly as a two-chain, active enzyme even in the absence of plasmin, a physiological activator. Here we show that the proclivity to autoactivate is not a unique property of the chicken uPA catalytic domain but requires sequences distinct from and independent of the serine protease domain. Human/chicken chimeric uPA molecules and point mutants were used to determine the structural requirements for uPA autoactivation versus zymogen stability. The amino terminal fragment of chicken uPA engineered onto the human uPA molecule can induce the autoactivation of the human uPA. In fact, the first twenty residues of the chicken uPA are necessary and sufficient to induce the autoactivation of chicken and human uPA. These results indicate that sequence motifs, distal to the active site, control the substrate specificity and catalytic efficiency of uPA activity in autolytic activation.
Contributions of Asn2198, Met2199, and Phe2200 in the factor VIII C2 domain to cofactor activity, phospholipid-binding, and von Willebrand factor-binding
Authors: Lewis Deborah , Pound Mary , Ortel Thomas 
Published: March 2018

SummaryThe crystal structure of the factor VIII C2 domain consists of a β-sandwich core from which β-hairpins and loops extend to form a hydrophobic surface. The hydrophobic surface includes M2199 and F2200 at the tip of the 1st β-hairpin. To determine the individual contributions of residues N2198, M2199, and F2200 to phospholipid and von Willebrand factor (vWF) binding properties of factor VIII, we prepared mutant proteins with single alanine substitutions. We found that single mutations at N2198 and M2199 had relatively little impact on cofactor activity, or phospholipid and vWF binding. However the F2200A mutant had slightly lower cofactor activity at subsaturating phospholipid concentrations. Competitive ELISAs suggested that F2200 plays a more important role in both phospholipid-binding and vWF-binding than N2198 and M2199. All mutant proteins were still recognized by a monoclonal antibody and two factor VIII inhibitors that neutralized cofactor activity and blocked factor VIII binding to phospholipids.Presented in part at the XVIII Congress of the International Society on Thrombosis and Haemostasis, Paris, France, 6-12 July 2001, and the 43rd Annual Meeting of the American Society of Hematology, Orlando, Florida, 7-11 December 2001
Effects of recombinant factor VIIa on platelet function and clot structure in blood with deficient prothrombin conversion
Authors: Martin Erika , Kuhn Jan , Seremetis Stephanie , Carr Marcus 
Published: March 2018

SummaryWhile recombinant factor VIIa (rFVIIa) shows promise as a broad-spectrum hemostatic agent, questions remain regarding the most appropriate dose and the best way to monitor its effects. In this study we tested the sensitivity of a thrombin dependent platelet assay, platelet contractile force, to the effects of rFVIIa in normal, factor-deficient, and inhibitor-containing blood samples. Dose dependent effects of rFVIIa on platelet contractile force (PCF) and clot elastic modulus (CEM) were measured in all blood samples.rFVIIa minimally affected PCF and CEM in normal blood clotted with thrombin or batroxobin. While rFVIIa minimally altered PCF and CEM in factor VIII (FVIII) deficient blood clotted with thrombin, rFVIIa increased PCF and CEM and shortened the lag phase in a dose dependent manner in batroxobin-induced clots. The effects of rFVIIa in factor IX (FIX) deficient blood mirrored the effects seen in FVIII deficient samples. Whether clotted with thrombin or batroxobin, baseline PCF and CEM were abnormally low in FVIII deficient samples containing FVIII inhibitors. In such samples, rFVIIa caused dose dependent improvement of PCF, CEM, and lag phases. In one patient with a spontaneous inhibitor, rFVIIa caused dose dependent increases in PCF and CEM in blood clotted with either enzyme.rFVIIa corrects the deficient thrombin generation seen in FVIII and FIX deficiency, and in blood containing FVIII inhibitors. As a consequence, platelet function is improved and clot structure is enhanced. Platelet contractile force and clot elastic modulus measurements are sensitive to the dose dependent effects of rFVIIa.
Stimulation of plasminogen activation by recombinant cellular prion protein is conserved in the NH2-terminal fragment PrP23-110
Authors: Praus Michael , Kettelgerdes Gerhard , Holzhütter Hermann-Georg , Jungblut Peter , Maissen Manuela , Epple Guido , Schleuning Wolf-Dieter , Köttgen Eckart , Aguzzi Adriano , Geßner Reinhard , Baier Michael 
Published: March 2018

Summary
Green tea epigallocatechin-3-gallate inhibits platelet signalling pathways triggered by both proteolytic and non-proteolytic agonists
Authors: Deana Renzo , Turetta Loris , Donà Massimo , Brunati Anna , Michiel Lucia , Garbisa Spiridione , Donella-Deana Arianna 
Published: March 2018

SummaryEpigallocatechin-3-gallate (EGCG), a component of green tea, inhibits human platelet aggregation and cytosolic [Ca2+]cincreases more strongly when these processes are induced by thrombin than by the non-proteolytic thrombin receptor activating peptide (TRAP), thromboxane mimetic U46619, or fluoroaluminate. In line with the previously demonstrated EGCG anti-proteolytic activity, a marked inhibition on aggregation is obtained by pre-incubation of thrombin with EGCG prior to addition to cellular suspension. The catechin also reduces cellular Ca2+ influx following thapsigargin-induced calcium emptying of endoplasmic reticulum, and the agonist-promoted cellular protein tyrosine phosphorylation. Both tyrosine kinases Syk and Lyn, immuno-precipitated from stimulated platelets, are greatly inhibited upon cellular pre-incubation with EGCG, which also inhibits the in vitro auto-phosphorylation and exogenous activity of these two enzymes purified from rat spleen. Both thrombin-induced aggregation and [Ca2+]c increase are reduced in platelets from rats that drank green tea solutions. It is concluded that EGCG inhibits platelet activation, by hindering the thrombin proteolytic activity, and by reducing the agonist-induced [Ca2+]cincrease through inhibition of Syk and Lyn activities.
Anandamide induces apoptosis in human endothelial cells: its regulation system and clinical implications
Authors: Yamaji Kazuyo , Sarker Krishna , Kawahara Koichi , Iino Satoshi , Yamakuchi Munekazu , Abeyama Kazuhiro , Hashiguchi Teruto , Maruyama Ikuro 
Published: March 2018

SummaryAnandamide (AEA), an endogenous cannabinoid, is generated by macrophages during shock conditions, and is thought to be a causative mediator of septic shock. Thus, we hypothesized that AEA plays a crucial role in endothelial cell (EC) injury. Here, we demonstrate that AEA induces apoptosis in a time-and dose-dependent manner in human umbilical vein endothelial cells (HUVECs). AEA triggered phosphorylation of c-Jun NH2-terminal kinase (JNK) and p38 mitogen activated protein kinase. AEA also showed a marked increase of interleukin 1β–converting enzyme (ICE)CED-3 family protease (caspase-3) activity. AEA-induced EC death was inhibited by a selective vanilloid receptor 1 (VR1) antagonist, capsazepine, and was enhanced by a VR1 agonist, capsaicin, indicating that AEA induces apoptosis in ECs via VR1. In conclusion, we propose that AEA may play a crucial role in EC injury under conditions of shock, and that the use of inhibitors of the AEA regulation system may have a therapeutic effect under these conditions.
Reactive oxygen species modulate HIF-1 mediated PAI-1 expression: involvement of the GTPase Rac1
Authors: Berchner-Pfannschmidt Utta , Wotzlaw Christoph , Cool Robbert , Fandrey Joachim , Acker Helmut , Jungermann Kurt , Görlach Agnes , Kietzmann Thomas 
Published: March 2018

SummaryThe hypoxia-inducible transcription factor HIF-1 mediates upregulation of plasminogen activator inhibitor-1 (PAI-1) expression under hypoxia. Reactive oxygen species (ROS) have also been implicated in PAI-1 gene expression. However, the role of ROS in HIF-1-mediated regulation of PAI-1 is not clear. We therefore investigated the role of the GTPase Rac1 which modulates ROS production in the pathway leading to HIF-1 and PAI-1 induction.Overexpression of constitutively activated (RacG12V) or dominant-negative (RacT17N) Rac1 increased or decreased, respectively, ROS production. In RacG12V-expressing cells, PAI-1 mRNA levels as well as HIF-1α nuclear presence were reduced under normoxia and hypoxia whereas expression of RacT17N resulted in opposite effects. Treatment with the antioxidant pyrrolidinedithiocarbamate or coexpression of the redox factor-1 restored HIF-1 and PAI-1 promoter activity in RacG12V-cells. In contrast, NFκB activation was enhanced in RacG12V-cells, but abolished by RacT17N. Thus, these findings suggest a mechanism explaining modified fibrinolysis and tissue remodeling in an oxidized environment.
Molecular characterization of coagulation factor XII deficiency in a Japanese family
Authors: Nishioka Junji , Kasai Yasunari , Kato-Nakazawa Keiko , Abe Yasunori , Morishita Yoshitaka , Nakatani Kaname , Nobori Tsutomu , Wada Hideo 
Published: March 2018

SummaryWe report the identification in a Japanese family of a novel homozygous W486C mutation in the protease domain of coagulation factor XII (FXII), which was associated with the reduction of plasma FXII activity and antigen level to less than 5% of normal. Sequences of each exon for FXII gene was analysed in family members by polymerase chain reaction (PCR) amplification followed by a direct sequencing method. Sequence analysis showed a homozygous substitution of G to C at nucleotide position 10587 (cDNA position 1458) in proband’s FXII gene, resulting in a Trp to Cys substitution in the catalytic domain of FXII. PCR-fragment length polymorphism analysis of 55 healthy volunteers showed no such mutation. Transient expression of FXII in HK-293T cells and analysis of FXII antigen in culture media and cell lysates showed reduced secretion of mutant protein by more than 84% relative to that of wild type protein although the intracellular contents were similar. Our results suggest that the reduced secretion of FXII protein was due to incorrect folding caused by the introduction of Cys486. We designated this mutation as FXII Mie-1.
Effect of hemostatic risk factors on the individual probability of thrombosis during pregnancy and the puerperium
Authors: Gerhardt Andrea , Zotz Rainer , Scharf Rüdiger 
Published: March 2018

SummaryIn a retrospective study of 190 women with a first history of venous thromboembolism during pregnancy and the puerperium and 190 age-matched women with at least one prior pregnancy and no history of venous thromboembolism, the individual probability of thrombosis was determined. Assuming an overall risk of 1 in 1500 pregnancies, the probability of pregnancy-related thrombosis in carriers of homozygous factor V Leiden was 1 in 80 (odds ratio 20.6, p=0.005) and among carriers of combined heterozygous factor V Leiden and heterozygous G20210A mutation in the prothrombin gene 1 in 20 (odds ratio 88, p<0.001). The probability of thrombosis per pregnancy among women with elevated levels of factor VIII:C (>172 % activity) was 1 in 385 (odds ratio 4.5, p<0.001) and among those with increased levels of von Willebrand factor antigen (>190 %) 1 in 435 (odds ratio 4.0, p=0.002), independent of elevated factor VIII:C levels. The high prevalence of combined and homozygous defects of hemostatic components (21.6%) in patients as compared with normal women (0.86%) supports the concept that venous thromboembolism is a multicausal disorder.
Thromboembolic risk in patients with high titre anticardiolipin and multiple antiphospholipid antibodies
Authors: Neville Carolyn , Rauch Joyce , Kassis Jeannine , Chang Erika , Joseph Lawrence , Le Comte Martine , Fortin Paul 
Published: March 2018

SummaryAsymptomatic antiphospholipid antibody (aPL) carriers with high risk for thrombosis may benefit from preventive anticoagulation.It was our objective to test whether the risk of thrombosis increases with: 1) increasing titres of anticardiolipin antibodies (aCL) after adjustment for other cardiovascular risk factors and 2) the number of aPL detected.In a cross-sectional study, blood was collected from clinics in two teaching hospitals. The study included 208 individuals suspected of having an aPL and 208 age- and sex-matched controls having blood drawn for a complete blood count.Clinical variables included history of previous arterial (ATE) or venous (VTE) thrombotic events, traditional risk factors for cardiovascular disease, and systemic lupus erythematosus (SLE). Laboratory variables included IgG/IgM aCL, lupus anticoagulant, and IgG/IgM anti-β2-glycoprotein I.Mean age was 46.5 years and 83% were female. Seventy-five of the 416 participants had > 1 aPL, and 69 had confirmed > 1 ATE or VTE. Family history was positive in 48% of participants, smoking in 28%, hypertension in 16%, diabetes in 6%, and SLE in 20%. A 10-unit increase in aCL IgG titre was associated with an odds ratio (OR) [95% CI] of 1.07 [1.01-1.13] for ATE and 1.06 [1.02 - 1.11] for VTE. The odds of a previous thrombosis increased with each additional aPL detected: 1.5 [0.93-2.3] for ATE and 1.7 [1.1-2.5] for VTE.These results indicate that increased titres of aCL and multiple aPL were associated with an increased risk of a previous thrombotic event.
Unexpected persistence of platelet hyporeactivity beyond the neonatal period: a flow cytometric study in neonates, infants and older children
Authors: Hézard Nathalie , Potron Gérard , Schlegel Nicole , Amory Catherine , Leroux Bernard , Nguyen Philippe 
Published: March 2018

SummaryPrevious studies, using flow cytometry, have reported a lower platelet reactivity in neonates compared to adults. Only few studies were carried out in older children, and results were controversial in terms of age to reach adult platelet function. We studied a total of 125 healthy neonates, infants and older children, and 15 adults. αIIbβ3 expression on resting and activated platelets was lower in all children, with an impaired capability of αIIbβ3 activation (PAC1 and bound fibrinogen). This defect was observed until the age of fifteen with a gradual recovery with age. In neonates, we observed a defect of GPIbα internalization, and demonstrated that this defect persisted in older children as well. In contrast with αIIbβ3 integrin activation, we did not observe a gradual age-dependent recovery. These unexpected results point out the need for reference values in childhood.
Differential effects of oral and transdermal postmenopausal estrogen replacement therapies on C-reactive protein
Authors: Oger Emmanuel , Le Gal Grégoire , Blouch Marie-Thérèse , Abgrall Jean-François , Kerlan Véronique , Scarabin Pierre-Yves , Mottier Dominique , Lacut Karine ,   and the SARAH investigators
Published: March 2018

SummaryC-reactive protein (CRP) is one of the main independent predictors of cardiovascular events. Oral post-menopausal estro-gen replacement therapy (ERT) increases CRP levels, but the effect of transdermal ERT is not well documented.CRP, interleukine-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels were evaluated in a randomised study of 196 healthy postmenopausal women, who were allocated to receive continuous oral estradiol-17β, (n=63) or transdermal estradiol-17β, (n=68) both combined with micronised progesterone, or placebo (n=65). Oral estrogen increased CRP levels compared with both placebo (p=0.010) and transdermal estrogen (p=0.004) at 6 months. There was no significant effect of transdermal estro-gen on CRP levels compared with placebo (p=0.997). No significant difference was found in the median changes for IL-6 and TNF-α between the three treatment groups.In conclusion, transdermal estrogen has no significant effect on CRP levels at 6 months, but CRP concentrations increased significantly with oral estrogen although no changes in cytokine levels were detected. The clinical relevance of these effects remains to be determined.
Haemostatic and Lipid Determinants of Prothrombin Fragment F1.2 and D-dimer in Plasma
Authors: Cooper Jackie , Martin Janet , Howarth David , Meade Thomas , Miller George , MacCalum Peter 
Published: March 2018

SummaryThe determinants of plasma levels of prothrombin fragment F1.2 (F1.2) and D-dimer in different populations are unclear and this may complicate their interpretation as predictors of thrombotic risk, particularly in the case of D-dimer. We therefore measured F1.2 and D-dimer levels together with a number of other haemostatic and lipid variables in a cross-sectional community-based study of 150 healthy adults (73 male, 77 female), age range 23-80 years, identified from the list of a general practice by stratified random sampling within sex and decade of age. Plasma F1.2 was significantly higher in females than males and was independently and positively associated with age, factor VII activity (FVIIc) and C1 inhibitor, and inversely associated with high density lipoprotein (HDL) cholesterol. Plasma D-dimer showed a quadratic association with age (p <0.0001). In those ≤55 years D-dimer was inversely associated with dilute clot lysis time (DCLT) and activated protein C (APC) ratio. In those >55 years it was significantly higher in females than males and associated positively with age, fibrinogen and, in males, activated factor XII (FXIIa). In a multiple-linear model which combined both age groups, F1.2 and D-dimer were independently associated with each other (r = 0.22, p = 0.03). Thus, thrombin generation and fibrin turnover/fibrinolysis are associated in healthy subjects. HDL cholesterol (inversely) and FVIIc are associated with basal thrombin generation (i.e. F1.2). Determinants of D-dimer differ according to age and interpretation of the biological significance of D-dimer levels in epidemiological studies may therefore not be straightforward.