bluuebunny/crossref_metadata_2025_split huggingface dataset:
Altered Platelet Shape Change in Hereditary Gelsolin Asp187Asn-related Amyloidosis
Authors: Javela Kaija , Somer Hannu , Kekomäki Riitta , Kiuru Sari 
Published: March 2018

SummaryHereditary gelsolin-related amyloidosis (AGel amyloidosis) is a systemic disorder caused by a G654A or G654T mutation in the gene coding for gelsolin, an actin-modulating protein. Altered platelet shape change has been demonstrated in gelsolin-deficient knock-out mice, but this has not been studied in humans with gelsolin deficiency. We measured platelet shape change, characterized by maximal decrease in light transmission (D) and reaction time (T), and aggregation, associated with stimulation of platelets with different agonists in platelet rich plasma, as well as coagulation factor VIII and ristocetin cofactor activities in 20 patients, 10 healthy sibs and 20 healthy control subjects. Statistically significant alterations of parameters describing platelet shape change (D, T) were observed after stimulation with adenosine diphosphate and collagen in patients when compared to healthy subjects, but not in maximal aggregation responses, platelet counts, coagulation factor VIII or ristocetin cofactor activity levels. Patients had more haemostatic derangements. Our results suggest that, in addition to amyloid deposition, the G654A gelsolin gene defect causes altered gelsolin-mediated cellular mechanisms, which may contribute, e. g., to bleeding tendency in AGel amyloidosis patients.
Inhibition of Platelet Thrombosis Using an Activated Protein C-loaded Stent: In Vitro and In Vivo Results
Authors: Gershlick Anthony , Hogrefe Kai , Baron Julia , Johnston Thomas , Hussey Amanda , Garner Ian , de Bono David , Foo Roger 
Published: March 2018

SummaryIn high-risk and complicated coronary intervention, the risk of acute closure is unpredictable. Thrombus and platelet deposition at the intervention site may also have further effects on subsequent restenosis. In vivo infusion of activated protein C has previously been shown to achieve potent anticoagulation without any haemostatic side effects. We now evaluated the in vitro and in vivo efficacy of polymer-coated coronary stents loaded with purified rabbit Activated Protein C (APC). By measuring 125I-fibrinogen/fibrin deposition APC-loaded stent-wires were antithrombotic compared to albumin-loaded, inhibited-APCloaded, plain polymer-coated and stainless steel stent-wires. In a balloon injury rabbit iliac artery model, APC-loaded stents did not occlude (0/14) compared to plain stents (9/15) and BSA-loaded stents (2/4). Relative 111In-labelled platelet deposition showed a similarly significant degree of inhibition. In conclusion, APC-loading could render stents significantly less thrombotic. Whether an effective antithrombogenic stent like this effectively reduces restenosis rates warrants further evaluation.
Effect of Exercise Training on Oxidized LDL-Mediated Platelet Function in Rats
Authors: Chow Shu-Er , Chen Jan-Kan , Wong May-Kuen , Wang Jong 
Published: March 2018

SummaryThis study investigates how exercise training affects Oxidized LDL (Ox-LDL) mediated-platelet activation. Five-week-old male Wistar rats were assigned to either control or trained groups. Trained rats were treadmill-trained for 10 weeks after familiarization. The following measurements were taken in both control and trained groups: Ox-LDLmediated platelet aggregability and [Ca2+]i, plasma and plateletderived nitric oxide (NO) metabolite (nitrite plus nitrate) levels, and antiaggregating activity of NO derived from endothelial cells. Based on those measurements, major findings in this study can be summarized as follows: 1) the trained group had a higher plasma -NO metabolite level than the control group; 2) the trained group had a lower platelet aggregability and [Ca2+]i elevation and a higher platelet derived-NO metabolite level than the control group; 3) the trained group had lower Ox-LDL-potentiated platelet aggregability and [Ca2+]i elevation and Ox-LDL-attenuated NO metabolite in platelet than the control group; 4) treating the platelet with L-arginine inhibited Ox-LDL-potentiated platelet activation in both control and trained groups; 5) Ox-LDL enhances platelet aggregation directly although impairing NO bioactivity but not guanylate cyclase activity in both control and trained groups. Results in this study demonstrate that exercise training decreases Ox-LDL-potentiated platelet activation most likely by enhancing platelet-derived NO release.
Location and Extent of Deep Vein Thrombosis in Patients with and without FV:R 506Q Mutation
Authors: Nilsson Paul , Nilsson Jan-Åke , Svensson Peter , Björgell Ola 
Published: March 2018

SummaryResistance to activated protein C due to FV:R 506Q mutation is the most common known genetic risk factor for deep leg vein thrombosis (DVT). The aim of this prospective study was to describe and compare the location and extent of DVT, reflected by a scoring system, in a group of patients with and without FV:R 506Q mutation. Of 247 consecutively included patients undergoing phlebography 105 had a DVT, 36 (35%) in the FV:R 506Q mutation group and 69 (65%) in the non-FV:R 506Q mutation group. Compared to the non-FV:R 506Q mutation group there was a significant increase in the incidence of DVT in the FV:R 506Q mutation group (p = 0.041, OR = 1.79 [1.02–3.15]), a significantly lower mean DVT score of the iliofemoral vein segments (p = 0.0081) and a significantly lower incidence of DVT in the iliofemoral vein segments (p = 0.007, OR = 10.6 [1.3–83.3]), 1/36 (2.8%) compared to 16/69 (23.2%). As controls 288 blood donors were included, with and without FV:R 506Q mutation and with no history of DVT in order to evaluate risk factors of DVT. The odds ratio of an iliofemoral DVT was 0.5 ([0.06–3.90), p = 0.50]) when FV:R 506Q mutation was present, compared to the control group, and at locations below the iliofemoral segments 5.28 ([3.01–9.28], p = less than 0.0001). Our findings provide the basis of a detailed phlebographic description and for the first time, to our best knowledge, shows a specific phlebographic pattern that may be linked to an inherited hypercoagulable state.
A Comparison of Point-of-Care Instruments Designed for Monitoring Oral Anticoagulation with Standard Laboratory Methods
Authors: Gosselin Robert , White Richard , Hutchinson Rose , Branch Jennifer , Mahackian Kathy , Johnston Marilyn , Larkin Edward , Owings John 
Published: March 2018

SummaryOur study compared point-of-care (POC) device monitoring with traditional clinical laboratory methods device of patients on oral anticoagulant therapy. The POC devices used in the study were Coumatrak, CoaguChek, CoaguChek Plus, Thrombolytic Assessment System (TAS) PT-One, TAS PTNC, TAS PT, Hemachron Jr. Signature, Protime Microcoagulation System, and Medtronics ACT II. The clinical laboratory method used thromboplastins with different ISI values: Innovin and Thromboplastin C Plus (TPC). All POC INRs showed strong correlation with both laboratory methods, with correlation coefficients of >0.900. All POC methods demonstrated a significant (p <0.05) difference in INR values, except the TAS PTNC and ACT II INRs (p: 0.12 and 0.71 respectively) when compared with Innovin INRs. All POC INRs were significantly different from TPC generated INRs (p <0.05). Comparisons of the POC INRs to the group mean of the POC methods, show higher correlation (R>0.93), but there were still significant (p<0.05) differences noted between the POC group INR mean and CoaguChek Plus, ACT II, TAS PT-One, TAS PTNC, and Hemachron Jr Signature INRs. These data indicate that POC INR biases exist between laboratory methods and POC devices. Until a suitable whole blood INR standardization method is available, we conclude that clinicians using point-of-care anticoagulation monitoring should be aware of differences between POC and parent laboratory values.
Cloning and Characterization of the Murine Coagulation Factor X Gene
Authors: Cooper Adrian , Liang Zhong , Castellino Francis , Rosen Elliot 
Published: March 2018

SummaryThe gene encoding murine coagulation factor X (fX) was isolated and characterized from a λFIX II library generated from murine genomic DNA. The 20130 bp sequence contains 18049 nucleotides that extend from the initiating methionine to the polyadenylation site. 1056 nucleotides 5’ of the start codon were determined and contain putative start sites for the FX mRNA as well as sites for binding of putative transcription factors. The sequence extends 1024 3’ of the polyadenylattion site.The gene contains 8 exons and 7 introns which were determined by comparing the mouse FX cDNA and gene sequences. The exonic structure of the gene is similar to that of the other mammalian vitamin K-dependent serine proteases of the coagulation system. These include an exon encoding the prepropepetide, the gladomain, a short helical stack, two exons for the two EGF domains, the activation pepetide, and two exons encoding the serine protease domain. The 5’ sequence of the mouse FX gene overlaps with the 3’ region of the FVII gene indicating that the murine FVII and FX gene are arranged in a head to tail arrangement as they are in humans.
Abbreviations: fVII, coagulation factor VII; fIX, coagulation factor IX; fX, coagulation factor X; PC, Protein C; fV, coagulation factor V; fVa, activated coagulation factor V; fVIII, coagulation factor VIII; fVIIIa, activated coagulation factor VIII.
Thromboxane Synthase Has the Same Pattern of Expression as Platelet Specific Glycoproteins during Human Megakaryocyte Differentiation
Authors: Vitrat Natacha , Letestu Rémi , Massé Aline , Lazar Vladimir , Debili Najet , Vainchenker William 
Published: March 2018

SummaryRegulation of the platelet formation process is poorly understood. It has been shown that p45NF-E2 deficient mice have a profound defect in platelet formation and recently the first platelet/megakaryocytic gene regulated by NF-E2, thromboxane synthase (TXS), has been identified. In this study, we investigated TXS expression as a model of a gene regulated by NF-E2 during MK differentiation. Megakaryocytic cells derived from blood CD34+ cells were purified according to their stage of maturation on the basis of expression of CD34, CD41a and CD42a, permitting to define different stages in MK differentiation. By means of real-time quantitative RT-PCR, we could determine that the level of TXS increased during differentiation in parallel with the expression of c-mpl and GPIIb (CD41). However, amounts of TXS transcripts increased about 1.6-fold more than that of GPIIb or c-mpl transcripts during maturation. Expression of TXS and MK specific proteins such as CD41a, CD42a and vWF was also correlated in maturing MKs. In addition, staining by anti-TXS antibody of proplatelet bearing MKs was not increased in comparison to that observed in mature MK, suggesting that TXS is not upregulated during platelet formation. In addition, we investigated whether TXS and cyclooxygenase could be involved in platelet formation by adding aspirin into the cultures. No significant decrease of platelet production was observed.In conclusion, this study shows that TXS is coordinately expressed with the other platelet proteins during MK differentiation but is not directly involved in platelet formation.
Mechanisms Involved in the Antiplatelet Activity of Staphylococcus aureus Lipoteichoic Acid in Human Platelets
Authors: Lee Cheng-Rong , Lin Chien-Huang , Hsiao George , Ko Wun-Chang , Chen Yao-Chang , Yen Mao-Hsiung , Sheu Joen-Rong 
Published: March 2018

SummaryIn this study, Gram-positive Staphylococcus aureus lipoteichoic acid (LTA) dose-dependently (0.1-1.0 µg/ml) and time-dependently (10-60 min) inhibited platelet aggregation in human platelets stimulated by agonists. LTA also dose-dependently inhibited phosphoinositide breakdown and intracellular Ca+2 mobilization in human platelets stimulated by collagen. LTA (0.5 and 1.0 µg/ml) also significantly inhibited thromboxane A2 formation stimulated by collagen in human platelets. Moreover, LTA (0.1-1.0 µg/ml) dose-dependently decreased the fluorescence of platelet membranes tagged with diphenylhexatrience. Rapid phosphorylation of a platelet protein of Mr. 47,000 (P47), a marker of protein kinase C activation, was triggered by PDBu (30 nM). This phosphorylation was markedly inhibited by LTA (0.5 and 1.0 µg/ml) within a 10-min incubation period.These results indicate that the antiplatelet activity of LTA may be involved in the following pathways: LTA’s effects may initially be due to induction of conformational changes in the platelet membrane, leading to a change in the activity of phospholipase C, and subsequent inhibition of phosphoinositide breakdown and thromboxane A2 formation, thereby leading to inhibition of both intracellular Ca+2 mobilization and phosphorylation of P47 protein. Therefore, LTA-mediated alteration of platelet function may contribute to bleeding diathesis in Gram-positive septicemic and endotoxemic patients.
Extended Anticoagulation for Prevention of Recurrent Venous Thromboembolism in Carriers of Factor V Leiden
Authors: Pistorio Angela , Barosi Giovanni , Marchetti Monia 
Published: March 2018

SummaryThere is much debate over the appropriateness of prescribing prolonged anticoagulation to heterozygous carriers of factor V Leiden suffering a first episode of deep vein thrombosis (DVT). We, thus used meta-analysis to estimate from six eligible studies the summary odds-ratio of recurrent DVT in carriers of factor V Leiden versus noncarriers: 1.36 (CI, 1.05–1.78). After that, we used a decision model to compare lifelong costs and benefits of 6 months standard anticoagulation with those of screening for carriers of factor V Leiden and extending for 2 years their anticoagulation. Screening was a cost-effective strategy, since it provided 2 additional quality-adjusted days of life per patient at the cost of $ 12,833 per quality-adjusted year of life saved, as compared to standard management. However, screening was not costeffective in patients who were predicted to incur fatal bleeding at a rate higher than 0.34% per year or recurrent DVT at a rate lower than 9% in the first 2 years. The screening policy was cost-saving if restricted to patients with idiopathic DVT and compliant to warfarin therapy.
Preliminary Evaluation of two New Rapid Immunoturbidimetric D-dimer Assays in Patients with Clinically Suspected Venous Thromboembolism (VTE)
Authors: Mihoubi Amine , Houdijk Wim , Qanadli Salah , Joseph Thierry , Courret Jean-Paul , Page Bernard , Goguel Alain , Houbouyan-Reveillard Lucie 
Published: March 2018

SummaryThe practical utility and diagnostic accuracy of two new rapid, automated and quantitative immunoturbidimetric D-dimer methods have been evaluated in a population of 123 randomly selected patients with suspected VTE. The STA Liatest D-dimer and MDA D-dimer methods are based on the photo-optical measurement of the rate of agglutination of antibody-coated latex particles. The VIDAS D-dimer automated Elisa was used as the reference method. Diagnosis was confirmed in 51 patients (29 PE, 19 DVT, 3 DVT+PE). The immunoturbidimetric methods compared favorably with the VIDAS Elisa as judged from the correlation coefficients of linear regression lines (r = 0.82, MDA vs VIDAS; r = 0.75, STA vs VIDAS) and areas under the curve of ROC plots (VIDAS 0.83; STA 0.83; MDA 0.81). At a discriminant value of 500 ng/mL, all three D-dimer assays showed high sensitivity (96-98%), high NPV (93-97%) and moderate specificity (39-42%). Reproducibility of results around the cut-off is an important aspect of the diagnostic utility of D-dimer assays. CV's of duplicate determinations in this critical zone showed average values of 5.4% and 17.0% for MDA and STA, respectively. These data demonstrate that such rapid and automated latex-based methods for the quantitative measurement of D-dimer hold promise as reliable and cost-efficient approaches for the exclusion of VTE. Prospective patient management studies will be required to confirm this.
A Study of Platelet Functions with a New Analyzer Using High Shear Stress (PFA100™) in Patients Undergoing Coronary Artery Bypass Graft
Authors: Fiemeyer Annick , Chatellier Gilles , Chammas Carine , Baron Jean-François , Aiach Martine , Lasne Dominique 
Published: March 2018

SummaryPlatelet dysfunction can be a major factor in excessive bleeding following cardiopulmonary bypass (CBP). A rapid, specific and sensitive method to identify platelet dysfunction would be a useful tool for identifying patients at an increased risk of bleeding. The ability of PFA100™, an in vitro bleeding test, to predict increased bleeding risk linked to platelet dysfunction was tested in 146 patients undergoing primary coronary artery bypass graft. Blood samples were taken the day before surgery, and 15 min and 5 h after heparin neutralization. The preoperative closure times (CT), i. e. the time required for platelets in citrated whole blood to occlude an aperture cut into a membrane coated with collagen plus either epinephrine (CTEPI) or adenosine diphosphate (CTADP) were longer in blood-group-O patients than in patients with other groups. The 15 min postoperative values were significantly longer from preoperative values essentially owing to CBP-induced hemodilution. Interestingly, 5 h after CBP, a significant reduction in CT values probably reflected platelet hyperaggregability. No correlation was found between calculated blood loss (CBL) and either preoperative or postoperative PFA values.
Evidence for New Endothelial Cell Binding Sites on Fibrinogen
Authors: Rooney Michael , Lord Susan , Mosesson M. W. , Gartner T. , Smith Richard 
Published: March 2018

SummaryIn vitro assays were used to characterize adhesion of human aortic, microvascular and umbilical vein endothelial cells to various forms of immobilized fibrinogen. All three types of endothelial cells adhered to fibrinogen in a manner that was independent of the Aα-chain 572-574 RGD cell binding site. In fact, all three adhered to a fragment of the molecule which is composed of only one D domain (D1) of fibrinogen. A time course study revealed that extensive adhesion of endothelial cells on the ligand coated surface occurred between one and two hours incubation. The anti-fibrinogen γA-chain monoclonal antibody 4A5 as well as 4A5 Fabs, blocked adhesion of endothelial cells to fibrinogen, not vitronectin. The inhibitory effects of 4A5 seemed to be indirect because the endothelial cells adhered to the recombinant fibrinogen γ407 (which lacks the γ-chain AGDV sequence of the carboxyl terminal 4A5 binding site) as well as they did to normal recombinant fibrinogen. A recombinant fibrinogen lacking the γ-chain AGDV sequence, containing RGE in place of RGD at the γ-chain 572-574 and 95-97 positions, also supported endothelial cell adhesion. The anti-αvβ3 antibody, LM609, blocked adhesion of endothelial cells to fibrinogen. The peptide GRGDSP inhibited endothelial cell adhesion on fibrinogen and vitronectin. These results demonstrate that αvβ3 mediated adhesion (attachment and spreading) of HUVECs to fibrinogen may use a site in the D domain of fibrinogen and is not dependent on the Aα-chain RGD (95-97 and 572-574) sequences, as has been shown in shorter term (where cells were rounded) experiments, or the γA-chain 408-411 cell binding sites. Thus, the data reveal the existence of another unidentified site(s) on fibrinogen which can support the irreversible adhesion (attachment and spreading) of endothelial cells.
Molecular Genetic Analysis of Factor XI Deficiency: Identification of Five Novel Gene Alterations and the Origin of Type II Mutation in Portuguese Families
Authors: Ventura Célia , Santos Ana I. , Tavares Alice , Gago Teresa , Lavinha João , McVey John , David Dezsö 
Published: March 2018

SummaryCoagulation factor XI (FXI) deficiency is an inherited autosomal recessive mild bleeding disorder. In this study, we report the molecular genetic analysis of FXI deficiency in six unrelated families of Portuguese origin. The Jewish type II mutation was found in two families, of seemingly Portuguese origin. Haplotype analysis in these families demonstrated that this mutation is of Jewish origin. In the remaining families, five novel FXI mutations have been identified. Two of these mutations (FXI IVS K -10T→A and FXI 1026G→T, cd 324) affect the FXI pre-mRNA splicing. A further two (FXI 307 ins AAGCAAT, cd 85 and FXI 1072 del A, cd 340) introduce frameshifts leading to premature termination codons. The FXI splicing mutation, 1026G→T cd 324, was found in compound heterozygosity with missense mutation FXI K518N. Analysis of the FXI mRNA from the latter genotype demonstrated new donor splice site usage. All reported mutations most likely result in functional null-alleles. In addition, three novel polymorphisms have been identified: at nt -138 in intron A, at codon D125 in exon 5 and at codon T249 in exon 8.
Three-dimensional Model of Coagulation Factor Va Bound to Activated Protein C
Authors: Pellequer Jean-Luc , Gale Andrew , Getzoff Elizabeth , Griffin John 
Published: March 2018

SummaryA complete molecular model of blood coagulation factor Va (FVa) bound to anticoagulant activated protein C (APC) and to a phospholipid membrane was constructed. The three homologous A domains and the two homologous C domains of FVA were modeled based on the X-ray crystallographic structures of ceruloplasmin and C2 domain of factor V, respectively. The final arrangement of the five domains in the complete FVa model bound to a membrane incorporated extensive published experimental data. FVa binds the phospholipid membrane through its C2 domain while the A-domain trimer is located from 40 through 100 Å above the membrane plane. From our model we infer a probable role for metal ions at the interface between FVa light and heavy chains, provide an explanation for the slower APC cleavage at Arg306 relative to Arg506, and predict specific interactions between positively and negatively charged exosites in APC and FVa, respectively.
Successful Attenuation of Venous Thrombus Growth in Rabbits after the Administration of a Novel Oral Thrombin Inhibitor
Authors: Keller Tymen , Biemond Bart , Peters Ron , Hornberger Wilfried , Büller Harry , Levi Marcel , Friederich Philip 
Published: March 2018

SummaryCurrent antithrombotic compounds have several limitations in clinical practice. The present study was designed to investigate a novel orally available direct thrombin inhibitor, BSF 208791. Intravenous administration of BSF 208791 showed superior antithrombotic properties as compared with Polyethylenglycol-Hirudin (PEG-Hirudin) and low molecular weight heparin (LMWH) in a model of venous thrombosis in rabbits. The thrombus growth was 22%, 30%, 37% and 50% after BSF 208791, PEG-Hirudin, LMWH, and saline administration, respectively. Moreover, bleeding time was less affected after administration of BSF 208791 as compared with PEG-Hirudin. The oral administration of BSF 208791 resulted in adequate bioavailability and significantly reduced venous thrombus growth to 36% as compared with 60% in the saline treated rabbits. The antithrombotic effect of BSF 208791 appears to be superior to PEG-Hirudin and LMWH without affecting the bleeding time. BSF 208791 is an orally available agent that might be a promising candidate for future antithrombotic therapy.