bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heparin-induced Thrombocytopenia: IgG Binding to PF4-Heparin Complexes in the Fluid Phase and Cross-reactivity with Low Molecular Weight Heparin and Heparinoid
Authors: Newman Peter , Swanson Rebecca , Chong Beng 
Published: March 2018

SummaryEarly diagnosis of heparin-induced thrombocytopenia (HIT) is essential to reduce morbidity and mortality. We report an enzyme immunoassay which detects the binding of HIT IgG to PF4-heparin in the fluid phase. Our fluid phase assay produces consistently low background and can detect low levels of anti-PF4-heparin. It is suited to testing alternative anticoagulants because, unlike in an ELISA, a clearly defined amount of antigen is available for antibody binding. We were able to detect anti-PF4-heparin IgG in 26/28 (93%) HIT patients. We investigated cross-reactivity of anti-PF4-heparin antibodies with PF4 complexed to alternative heparin-like anticoagulants. Low molecular weight heparins cross-reacted with 23/26 (88%) of the sera from HIT patients while half of the HIT sera weakly cross-reacted with PF4-danaparoid (Orgaran). The thrombocytopenia and thrombosis of most of these patients resolved during danaparoid therapy, indicating that detection of low affinity antibodies to PF4-danaparoid by immunoassay may not be an absolute contraindication for danaparoid administration.
Prevention and Therapy of Experimental Venous Thrombosis in Rabbits by Desmin 370
Authors: Rossiello Maria Rosaria , Barbanti Miriam , Calanni Fiorella , Semeraro Nicola , Colucci Mario 
Published: March 2018

SummaryDesmin 370 (D370), a low molecular weight dermatan sulfate, has been shown to reduce the size of preformed thrombi in rats, via a mechanism largely independent of its anticoagulant activity. In the present study we investigated the therapeutic efficacy of D370 in rabbits with experimental jugular vein thrombosis. Experiments performed to evaluate the antithrombotic dosages in rabbits indicated that D370 prevented the formation of venous thrombi (Wessler model) in a dose-dependent manner with complete inhibition at 20 mg/kg. When injected to rabbits bearing a 30 min aged thrombus, D370 caused a time- and dose-dependent reduction in thrombus weight. Thrombi harvested 2 h after injection of 50 mg/kg of D370 were 71% smaller than thrombi from saline-treated rabbits and 50% smaller than pretreatment thrombi, suggesting a double effect of the drug: inhibition of thrombus accretion and reduction of the existing thrombus. Interestingly, pretreatment with the fibrinolytic inhibitor EACA (1 g/kg), significantly attenuated the therapeutic efficacy of D370, suggesting a possible involvement of the fibrinolytic system. Heparin (50 and 200 U/kg) was less active as therapeutic agent, the maximal decrease in thrombus weight, as compared to untreated rabbits, amounting to 38%. Heparin, moreover, caused a more pronounced prolongation of APTT than comparable antithrombotic dosages of D370. Our present data extend previous results on the therapeutic efficacy of D370 and underscore its potential as an alternative antithrombotic drug.
Thromboembolic Complications Associated with the Use of Prothrombin Complex and Factor IX Concentrates
Authors: Hellstern Peter , Lechler Eckhard , Überfuhr Peter , Müller-Berghaus Gert , Köhler Michael 
Published: March 2018

SummaryIn 1994, shortly after a heat-treated prothrombin complex concentrate (PCC) had been withdrawn from the German market due to transmission of hepatitis B, the license of another brand was withdrawn, due to 3 acute fatalities associated with the use of this product. We report on the clinical data of altogether 5 patients, who died during a 3 month period in Germany after having received this brand of PCC. All patients had surgery, acquired deficiencies of coagulation factors, and underlying diseases predisposing for thrombosis or disseminated intravascular coagulation. PCC was administered for the prevention of bleeding. In three patients, a drug interaction of PCC with aprotinin may also have played a role. Several points, however, are suspicious of a major causative effect of the respective product, (a) the close temporal correlation between administration of the drug and the subsequent clinical as well as laboratory deterioration, (b) the accumulation of these adverse events in a short period of time, when the use and market share of this brand increased due to the shortage of other products, and (c) laboratory abnormalities of this brand which have been consistently observed in several in vitro studies.
Tissue Factor as a Therapeutic Target
Authors: Bach Ronald , Key Nigel 
Published: March 2018

SummaryTissue factor (TF) is a member of the cytokine receptor superfamily that functions as the essential receptor and co-factor for factor VII/ VIIa. Assembly of the TF-VII(a) complex on cellular surfaces initiates blood coagulation by limited proteolysis of zymogen factors IX and X, ultimately leading to the generation of thrombin. The realization that the TF pathway is the primary (if not the sole) mechanism for activation of coagulation in vivo has sparked an explosion in research in the last decade that has documented the central role of TF in certain forms of pathological thrombosis. Although these are too numerous to list, several are especially noteworthy by virtue of strongly supportive data in animal models. These include disseminated intravascular coagulation (DIC) induced by sepsis, and arterial thrombosis overlying an atherosclerotic plaque - the usual final event in myocardial infarction and unstable angina. In the case of arterial injury, inhibition of TF in animal models has also suggested that this pathway is important in mediating intimal hyperplasia. Other recent seminal observations include the recognition of several possible roles for TF that may not depend upon activation of the coagulation mechanism. For example, TF expression by certain tumor cell lines may determine enhanced metastatic potential, and in some tumors TF may promote angiogenesis (1).
Crystal Structures of Fragments D and Double-D from Fibrinogen and Fibrin
Authors: Spraggon Glen , Everse Stephen , Doolittle Russell 
Published: March 2018

IntroductionAfter a long period of anticipation,1 the last two years have witnessed the first high-resolution x-ray structures of fragments from fibrinogen and fibrin.2-7 The results confirmed many aspects of fibrinogen structure and function that had previously been inferred from electron microscopy and biochemistry and revealed some unexpected features. Several matters have remained stubbornly unsettled, however, and much more work remains to be done. Here, we review several of the most significant findings that have accompanied the new x-ray structures and discuss some of the problems of the fibrinogen-fibrin conversion that remain unresolved.
* Abbreviations: GPR—Gly-Pro-Arg-derivatives; GPRPam—Gly-Pro-Arg-Pro-amide; GHRPam—Gly-His-Arg-Pro-amide
Cyclic Nucleotide Phosphodiesterases (PDEs): Diverse Regulators of Cyclic Nucleotide Signals and Inviting Molecular Targets for Novel Therapeutic Agents
Authors: Degerman E. , Manganiello V. C. 
Published: March 2018

IntroductionCyclic adenosine 3’5’-monophosphate (cAMP) and cyclic guanosine 3’5’-monophoshpate (cGMP) are critical intracellular second-messengers involved in the transduction of a wide variety of extracellular stimuli, including peptide hormones, growth factors, cytokines, neurotransmitters and light. These messengers modulate many fundamental biological processes, including growth, differentiation, apoptosis, glycogenolysis, lipolysis, immune/inflammatory responses, etc.By catalyzing hydrolysis of cAMP and cGMP, cyclic nucleotide phosphodiesterases (PDEs) are important determinants in regulating the intracellular concentrations and, consequently, the biological actions of these second-messengers (Fig. 1). The advent of molecular genetics has revealed the extraordinary complexity and diversity of the mammalian PDE superfamily, which contains at least 10 highly regulated and structurally-related gene families (PDEs 1-10).1-8 As depicted in Figure 1, some PDEs are highly specific for hydrolysis of cAMP (PDEs 4,7,8), some are cGMP-specific (PDEs 5,6,9), and some exhibit mixed specificity (PDEs 1,2,3,10). Most gene families are comprised of more than one isogene (indicated by A-D in Table 1). At least 19 genes encoding more than 30 isoforms have been identified. PDE families differ with respect to their primary structures, sensitivity to specific inhibitors, tissue distribution, subcellular localization, and mechanisms of regulation (Table 1).2-6 Within individual families, different mRNAs are generated from the same gene by use of different transcription initiation sites or by alternative mRNA splicing. These variant PDE isoforms are often tissue-specific and selectively expressed in various tissues and cell types.2-6 The importance of cyclic nucleotide signaling in cell regulation and the molecular diversity of PDEs has presented targets for selective interventions and development of family-specific PDE inhibitors as therapeutic agents. This brief review will discuss some general characteristics of PDEs and then focus on the cellular biology and diverse functions of different PDE isoforms and their potential as therapeutic targets.
Molecular Genetics of von Willebrand Disease
Authors: Ginsburg David 
Published: March 2018

IntroductionVon Willebrand disease (vWD) is a common inherited bleeding disorder that is notable for a high degree of variability in clinical presentation and the considerable heterogeneity of its molecular basis. Confusion about the genetic origin of this disorder has existed since its original description by Eric von Willebrand in 1926.1 Dr. von Willebrand coined the term “pseudohemophilia” to describe the disease in the original pedigree. Though it resembled the bleeding diathesis of hemophilia, von Willebrand also noted findings suggesting an abnormality in platelet function. The severity of bleeding in this family varied widely from mild bleeding to severe hemorrhage, the latter resulting in the death of the proband at the time of her fourth menstrual period.Von Willebrand incorrectly characterized the inheritance pattern in the original Åland Island pedigree as X-linked dominant, because of the apparent greater frequency of the disease in female patients. Now, it is recognized that the greater frequency was largely by chance and due to increased penetrance related to the hemostatic stresses of menstruation and pregnancy. Nonetheless, von Willebrand clearly distinguished the inheritance pattern of vWD from that of classic hemophilia. It is now known that vWD is due to either quantitative or qualitative defects in von Willebrand factor (vWF), encoded by a gene on chromosome 12, whereas hemophilia is due to mutations in the factor VIII gene on the X chromosome.2
Regulation of Leukocyte-Endothelium Interaction by Fibrinogen
Authors: Altieri Dario 
Published: March 2018

IntroductionThe binding of neutrophils and mononuclear cells to vascular endothelium is an essential prerequisite in maintaining effective immune-inflammatory responses. This process has been unraveled as a regulated “adhesion cascade” that involves the expression of multiple adhesion receptors of the integrin, selectin, and immunoglobulin gene superfamilies on both cell types. These adhesive interactions are modulated by disparate environmental signals, ranging from inflammatory and chemotactic cytokines to changes in shear force at the vessel wall. Although of paramount importance in the preservation of immune-inflammatory surveillance, dysregulation of leukocyte-endothelium interaction also constitutes one of the earliest molecular events in the pathogenesis of such vascular diseases as atherosclerosis. This dysregulation leads to the aberrant accumulation of mononuclear cells in the damaged intima.Recently, the interaction of fibrinogen with vascular cells has emerged as an alternate mechanism for recruiting leukocytes at the site of vascular injury. Although the role of fibrinogen as a risk factor for atherosclerosis has long been recognized, this pathway has been associated with complex mechanisms of intercellular adhesion, signal transduction, second-messenger generation, and modulation of gene expression in vascular cells. These studies have revealed a multifaceted and far-reaching molecular link between inflammation and hemostasis–a link that is of potential therapeutic relevance for the pathogenesis of vascular diseases.
Catheter-Directed Thrombolysis of Peripheral Arterial Occlusions and Deep Vein Thrombosis
Authors: Kandarpa Krishna 
Published: March 2018

IntroductionThis chapter describes the current status of catheter-directed lytic therapy for occlusive thrombi of arteries and veins. A recent international consensus document, concerning the use of lytic therapy for symptomatic lower extremity arterial thrombi, has been endorsed by several international societies.1 A review of this document will serve to summarize current opinion on this topic. The present chapter addresses issues such as patient selection, techniques, and therapeutic efficacy. The techniques of arterial thrombolysis are being adapted to treat venous thrombi. Early results in the venous system are encouraging, but the long-term efficacy is yet to be established.
Fine Mapping of Inhibitory Anti-factor V Antibodies Using Factor V C2 Domain Mutants
Authors: Izumi Tomonori , Greist Anne , Macedo-Ribeiro Sandra , Fuentes-Prior Pablo , Bode Wolfram , Kane William , Kim Suhng Wook , Ortel Thomas 
Published: March 2018

SummaryHemorrhagic factor V inhibitors frequently bind to the second C-type (C2) domain of factor V and interfere with phospholipid binding. To define specific residues recognized by inhibitors from four patients (one bovine thrombin-induced and three spontaneous antibodies), epitope mapping was performed using recombinant human factor V lacking most of the B-type domain (FV des B) and alanine-substituted mutants within the C2 domain (FV des B C2 mutants). FV des B C2 mutants located in the region between Lys2060 and Glu2069 were resistant to inhibition by three IgG preparations including the bovine thrombin-induced antibody in both prothrombinase and phospholipid-binding assays. In contrast, mutations at Lys2087 and Lys2092/ Glu2096 were significantly resistant to inhibition by the fourth IgG preparation in both prothrombinase and phospholipid-binding assays. These results confirm interference of phospholipid binding by hemorrhagic factor V inhibitors and support the role(s) of these residues in phospholipid binding.Presented in part at the 41st Annual Meeting of the American Society of Hematology, New Orleans, Louisiana, December 3–7, 1999
Myocardial Troponin T Release Is Associated with Enhanced Fibrinolysis in Patients with Acute Coronary Syndromes
Authors: Büttcher Eva , Kazmaier Silke , Beyer Martin , Helber Uwe , Szabo Sebastian , Wendel Hans Peter , Hoffmeister Hans Martin , Ehlers Raila 
Published: March 2018

SummaryPatients with acute coronary syndromes (ACS) frequently present with signs of disturbed fibrinolysis. The present study investigates the correlation of alterations in the fibrinolytic system and the amount of myocardial damage characterized by troponin release.In 85 patients with ACS markers of plasmin activation, plasminogen activator system and troponin T (TnT) were measured initially and after 48 h. Patients with TnT release (≥ 0.01 g/l) at admission had higher TPA levels than those without release (10.2 ± 0.7 ng/ml vs. 7.6 ± 0.5 ng/ml; p <0.01). Additionally, patients with positive TnT had higher D-dimer levels initially (457 ± 39 ng/ml vs. 316 ± 22 ng/ml; p < 0.01) and 48 h later (451 ± 42 ng/ml vs. 275 ± 37 ng/ml; p < 0.01). The association of myocardial damage with a prothrombotic state and an enhanced fibrinolysis may explain the high prognostic value of troponin measurements in respect to future coronary events.
Imbalance of Plasminogen Activator Inhibitor-I/ Tissue Plasminogen Activator and Tissue Factor/Tissue Factor Pathway Inhibitor in Young Japanese Men with Myocardial Infarction
Authors: Saigo Masahiko , Ogawa Masakazu , Yamashita Tsuminori , Biro Sadatoshi , Minagoe Shinichi , Maruyama Ikuro , Tei Chuwa , Abe Satoshi 
Published: March 2018

SummaryTo evaluate the association between haemostatic parameters and increased risk of myocardial infarction (MI) at a young age, we measured fibrinogen, factor VII, antithrombin III, protein C, protein S, tissue factor (TF), free form tissue factor pathway inhibitor (TFPI), plasminogen, 2-antiplasmin, tissue plasminogen activator (tPA), plasminogen activator inhibitor-I (PAI-I), and lipoprotein (a) in 140 young men with MI before age 45 and 150 age-matched healthy men. TF, TF/TFPI ratio, PAI-I, PAI-I/tPA ratio, plasminogen, and lipoprotein (a) in young MI patients were all significantly higher than controls, while TFPI, antithrombin III, and tPA were significantly lower (P <0.001 of each). Significant determinants of MI risk were PAI-I/tPA ratio (R2 = 0.300, P <0.001), TF/TFPI ratio (R2 = 0.049, P <0.001), antithrombin III (R2 = 0.034, P <0.001), hyperlipidaemia (R2 = 0.019, P = 0.004), diabetes (R2 = 0.014, P = 0.015), lipoprotein (a) (R2 = 0.012, P = 0.023), 2-antiplasmin (R2 = 0.014, P = 0.012), and protein C (R2 = 0.012, P = 0.018). We conclude that the imbalances of PAI-I/tPA and TF/TFPI are significantly associated with MI at a young age, perhaps mediated via impaired fibrinolytic activity.
Role of Protease-activated Receptor 1 in Tumor Metastasis Promoted by Tissue Factor
Authors: Bailly Michelle , Konigsberg William , Bromberg Michael 
Published: March 2018

SummaryTissue factor (TF) is a transmembrane glycoprotein that complexes with factor VIIa to initiate blood coagulation. We previously reported that expression of high levels of TF in a human melanoma cell line promotes metastasis. Both the cytoplasmic domain of TF and its extracellular domain complexed with factor VIIa are required for the meta-static effect. To further explore the mechanism of TF-mediated metastasis, we investigated the possibility that a protease-activated receptor (PAR) might play a role. For this purpose, we first determined the expression levels of the known PARs (PAR1-4) in a human melanoma cell line, SIT1, that has low endogenous levels of TF and low meta-static potential. We found negligible levels of all of the known PARs and transfection of this cell line with human TF cDNA did not alter expression of the known PARs. To study the possible role of PAR1 in TF-mediated metastasis, we prepared a panel of transfected cell lines with varying levels of TF and PAR1. Our studies show that TF promotes metastasis by a pathway that does not involve high expression of known PARs by tumor cells. In addition, while overexpression of PAR1 is insufficient to induce metastasis in cells with low TF expression, it enhances the metastatic potential of cells with high TF expression, indicating a possible synergy between TF and PAR1 in promoting metastasis.
The Kringle V-Protease Domain Is a Fibrinogen Binding Region within Apo(a)
Authors: Xue Song , Madison Edwin , Miles Lindsey 
Published: March 2018

SummaryLp(a) binds directly to fibrin and competes for the interaction of plasminogen with this substrate. This competition may play a role in the proatherothrombogenic consequences of high Lp(a) levels. Previous studies by us and others showed that apo(a) Kringle IV-10 competes for the interaction of Lp(a) with plasmin-treated fibrinogen. However, kringle IV-10 cannot account for the entire high affinity interaction of Lp(a) with fibrinogen. Therefore, we tested the hypothesis that the apo(a) kringle V protease-like domain (KV-PD) could interact with plasmin-treated fibrinogen. We cloned the apo(a) KV-PD region from a human liver cDNA library. Fusion apo(a) KV-PD was expressed in COS 7 cells and purified from the conditioned media. Western blotting of the apo(a) KV-PD protein revealed two bands migrating with apparent molecular weights of 45K and 48K. When fusion apo(a) KV-PD was treated with O-glycosidase and neuraminidase, the higher molecular weight band disappeared suggesting that the apo(a) KV-PD was O-glycosylated. Apo(a) KV-PD bound to plasmin-treated fibrinogen in a dose-dependent fashion. An EC50 of 3.9 ± 0.2 μM was determined for this interaction. Treatment of the apo(a) KV-PD with O-glycosidase did not significantly affect its ability to bind to plasmin-treated fibrinogen. In addition, apo(a) KV-PD competed for the binding of 125I-Lp(a) to plasmin-treated fibrinogen. An IC50 of 7.90 ± 0.95 μM was obtained. Our data suggest that the KV-PD of apo(a) shares binding sites on plasmin-treated fibrinogen with Lp(a) and also may participate in the interaction of the Lp(a) particle with plasmin-treated fibrinogen.
A Missense Mutation (Tyr88 to Cys) in the Platelet Membrane Glycoprotein Ibβ Gene Affects GPIb/IX Complex Expression
Authors: Kurokawa Yumi , Kamijo Takehiko , Kunishima Shinji , Kenny Dermot , Kitano Kiyoshi , Koike Kenichi , Ishida Fumihiro 
Published: March 2018

SummaryThis study examined the molecular basis of a missense mutation of the platelet glycoprotein (GP) Ibβ gene in two families. In the propositus with a novel form of Bernard-Soulier syndrome (BSS) from Family I, only GPIbα was detectable in reduced amounts on platelet surfaces by flow cytometry. There were no GPIX or GPIbβ found by immunoblotting. DNA sequencing analysis showed a homozygous mutation in the GPIbβ gene which changed Tyr (TAC) to Cys (TGC) at residue 88. Her parents were heterozygous for Tyr88Cys in the GPIbβ gene. In transient transfection studies on 293T cells, both Tyr88Cys and Tyr88Ala mutations suppressed the expression of GPIb/IX complexes. In addition, Tyr88Cys GPIbβ mutation was found to exert a dominant negative effect on the GPIb expression.Five individuals from Family II, four of whom reported elsewhere as having giant platelet disorders with normal aggregation (BLOOD, 1997; 89: 2404) and one newly analyzed in this study, were heterozygous for Tyr88Cys in the GPIb gene. Microsatellite analysis of chromosome 22 showed a common haplotype in 8 of the individuals with Tyr88Cys mutations in Families I and II. Tyr88 in the GPIbβ gene plays a significant role in the GPIb/IX expression; the defect causes BSS in a homozygous form and possibly giant platelets in a heterozygous form.
The Value of Ultrasound Screening for Proximal Vein Thrombosis after Total Hip Arthroplasty
Authors: Verlato Fabio , Bruchi Olinto , Camporese Giuseppe , Maso Gianni , Busonera Flavio , Girolami Antonio , Andreozzi Giuseppe Maria , Prandoni Paolo ,   for the W. O. D. O. S. Investigators Group
Published: March 2018

SummaryThe role of ultrasound screening for proximal deep-vein thrombosis (DVT) following major hip surgery is controversial. 202 consecutive patients, who had received warfarin prophylaxis after total hip arthroplasty underwent a bilateral ultrasound assessment of the proximal vein system (using the criterion of vein compressibility) before hospital discharge. In the 9 patients (4.5%; 95% CI, 2.1-8.3%) with positive test anticoagulant treatment was successfully continued for three months. In all the remaining 193 patients the warfarin treatment was withdrawn. A second ultrasound test was performed 15 days later, and showed a new (asymptomatic) abnormality compatible with proximal DVT in 2 patients (1.0%; 95% CI, 0.1-3.7%). All other 191 patients remained asymptomatic until the completion of a 3-month follow-up period (rate of symptomatic thromboembolism, 0/191, 0%; 95% CI, 0-1.9%).Because of the relatively high incidence of proximal DVT in patients undergoing major orthopaedic surgery under warfarin prophylaxis, screening for proximal DVT at hospital discharge in these patients is indicated. The negativity of this test has the potential of safely preventing the extension of anticoagulation beyond hospital stay. A larger controlled study in which the value of this strategy is tested against the prolongation of oral anticoagulation in patients with a negative ultrasound screening at discharge is indicated.