bluuebunny/crossref_metadata_2025_split huggingface dataset:
A rapid, automated flow cytometric method to measure activated degranulated platelets by density determination
Authors: Sorette Martin , Hetherington Edward , Zelmanovic David , Kling Gail , Dugailliez Jacques , Pujol-Moix Nuria , Okrongly David , Chapman Sabrinah 
Published: March 2018

SummaryPlatelet activation is reported to correlate with acute coronary syndromes. A platelet analysis method on the ADVIA®120 Hematology System provides rapid analysis of platelet density, reported as mean platelet component (MPC) concentration, utilizes routine hematology specimens, requires no pre-treatment, and thirty seconds to generate results. Sub-populations of platelets separated by density gradients showed excellent correlation with the ADVIA 120 MPC parameter (r = 0.997). Platelet activation induced by thrombin treatment resulted in a shift of platelets into the lowest density fraction (d ≤ 1.068 g/mL) with a corresponding reduction in MPC from 24.7 to 20.6 g/dL, N = 4 subjects (p < 0.004). There was also excellent correlation between expression of CD62P measured by fluorescence flow cytometry and the ADVIA 120 Hematology System MPC values (r = 0.85). These results indicate that the ADVIA 120 MPC parameter may be a useful new test for assessing activated platelets and platelet density.
PAI-1 level and the PAI-1 4G/5G polymorphism in relation to risk of non-fatal myocardial infarction
Authors: Wiman Björn , Hallqvist Johan , Sten-Linder Margareta , de Faire Ulf , Leander Karin 
Published: March 2018

SummaryThis study examines the relationship between plasma Plasminogen Activator Inhibitor-1 (PAI-1) activity and the PAI-1 4G/5G polymorphism, and their association with the risk of myocardial infarction (MI). Furthermore, this study explores whether a high level of PAI-1 or whether the PAI-1 4G/5G polymorphism synergistically interacts with any established environmental risk factor for MI. This case-referent study of subjects aged 45-70 and living in Stockholm includes 851 men and 361 women with first-time MI and 1051 men and 505 women who were randomly chosen as referents from a population register. The adjusted odds ratio (OR) of MI was 1.9 (95% confidence interval [CI] 1.4-2.8) for men with a plasma PAI-1 activity level greater than the 90th percentile value of referents. The corresponding OR for women was 1.5 (95% CI 0.9-2.5). A strong indication of synergistic interaction was found in men for the co-exposure to high plasma PAI-1 activity and current smoking, an adjusted synergy index score of 3.9 (95% CI 1.2-13.2). In women, the 4G allele was associated slightly with an increased risk of MI, OR 1.4 (95% CI 1.0-1.9). This association was not found in men. There were no clear indications of synergistic interaction effects involving the PAI-1 4G/5G polymorphism and the environmental exposures considered (cigarette smoking, physical inactivity, overweight, diabetes mellitus, hypercholesterolaemia, hypertension, high C-reactive protein and hypertriglyceridaemia).
Impact of pretreatment thrombocytosis on survival in primary breast cancer
Authors: Salat Andreas , Gnant Michael , Kwasny Werner , Mlineritsch Brigitte , Menzel Rainer-Christian , Schmid Marianne , Smola Michael , Stierer Michael , Tausch Christoph , Galid Arik , Steger Günther , Jakesz Raimund , Taucher Susanne 
Published: March 2018

SummaryPlatelet count has been reported to have predictive value in various cancer entities. In the case of breast cancer, evidence about involvement of platelets is still incomplete. Our objective was to assess the influence of pretreatment thrombocytosis on survival and establish its prognostic relevance for breast cancer patients.We performed a retrospective, multivariate analysis of 4,300 patients with early-stage breast cancer. All subjects participated in one of five prospective, randomized, multicenter trials conducted by the Austrian Breast and Colorectal Cancer Study Group. Thrombocytosis was defined as a platelet count exceeding 400 G/L. Median follow-up was 52 months. Univariate and multiple Cox regression models were calculated for overall survival (OS), breast cancer-related survival and disease-free survival (DFS). Pretreatment thrombocytosis was observed in 161 patients (3.7%). Estimated median OS, breast cancer-related survival and DFS for patients with versus those without thrombocytosis was 71.0 versus 99.5, 72.0 versus 100.9, and 80.4 versus 88.4 months, respectively (p = 0.0054, p = 0.0095, p = 0.0199). A multiple Cox regression model including tumor and nodal status, grading, age, hormone receptor status and pretreatment thrombocytosis identified pretreatment thrombocytosis as an independent predictive factor for OS (p = 0.0064) and breast cancer-related survival (p = 0.0162). Multivariate analysis failed to identify pretreatment thrombocytosis as an independent risk factor for DFS (p = 0.1355).In our retrospective study, elevated platelet counts at time of diagnosis were associated with poor prognosis in breast cancer. We hypothesize that platelets may contribute to the patho-physiology of hematogenous metastasis.
V34I and V34A substitutions within the factor XIII activation peptide segment (28-41) affect interactions with the thrombin active site
Authors: Trumbo Toni , Maurer Muriel 
Published: March 2018

SummaryIn the blood coagulation cascade, thrombin helps activate Factor XIII by cleaving the Factor XIII Activation Peptide at the R37-G38 peptide bond. The common polymorphism V34L yields a Factor XIII that is more easily activated than the wild-type enzyme. Peptides based on the Factor XIII (28-41) ( 28TVELQGVVPRGVNL41) sequence serve as an important model system for evaluating how to regulate thrombin activation of Factor XIII and subsequently fibrin clot character. Kinetic and NMR (1D proton line broadening and 2D transferred NOESY) studies have revealed that the P4-P1 region of the activation peptides is critical for binding to the thrombin surface. These results have led to an interest in exploring two new mutations at the P4 position including V34I and V34A. The V34I peptide was found to have the lowest Km of the peptides studied. However, unlike the V34L peptide, there are no P4 to P2 interactions observed in the transferred NOESY spectrum. The Leu thus promotes a bound conformation that cannot be achieved with the similar amino acid Ile. The V34A peptide exhibited a decrease in Km but also a substantial decrease in kcat. With this smaller amino acid, 1D proton line broadening NMR studies indicate that further contact of the Q32 residue with the thrombin surface is now possible. From these studies, valuable kinetic and structural information is being obtained to characterize interactions between thrombin and the Factor XIII activation peptide.Theme paper: Part of this paper was originally presented at the joint meetings of the 16th International Congress of the International Society of Fibrinolysis and Proteolysis (ISFP) and the 17th International Fibrinogen Workshop of the International Fibrinogen Research Society (IFRS) held in Munich, Germany, September, 2002.
Formation of platelet microaggregates correlates with adverse clinical outcome in patients with coronary artery disease
Authors: Miyamoto Shinzo , Kawano Hiroaki , Sakamoto Tomohiro , Soejima Hirofumi , Kajiwara Ichiro , Shimomura Hideki , Kojima Sunao , Hokamaki Jun , Sugiyama Seigo , Hirai Nobutaka , Yoshimura Michihiro , Ozaki Yukio , Ogawa Hisao 
Published: March 2018

SummaryPlatelet activation plays a pivotal role in the pathogenesis of acute coronary syndromes. Laser-light scattering in a platelet aggregometer was used to evaluate aggregate size and number quantitatively. Small platelet aggregates ultimately develop into medium and then large platelet aggregates. Thus the measurement of small platelet aggregates is important in the evaluation of thrombus formation.We examined the relationship between small platelet aggregates and the occurrence of subsequent cardiovascular events. We followed-up 204 patients (149 men and 55 women, mean age 68 ± 9 years) with coronary artery disease (CAD) for 48 months. Blood sampling to determine platelet aggregation was performed on the day of hospital discharge.The degree of small platelet aggregates [relative risk 4.34, 95% confidence interval (1.62-11.7), p = 0.004] and low left-ventricular ejection fraction [relative risk 2.88, 95% confidence interval (1.23-6.73), p = 0.015] were independent predictors of the occurrence of cardiovascular events in multivariate Cox hazard analysis. In Kaplan-Meier analysis, the degree of small platelet aggregates correlated with the probability of cardiovascular event occurrence.In patients with CAD, an increase in small platelet aggregates is closely correlated with the future occurrence of cardiovascular events
Blood Coagulation Factor X Deficiency Causes Partial Embryonic Lethality and Fatal Neonatal Bleeding in Mice
Authors: Dewerchin Mieke , Liang Zhong , Moons Lieve , Carmeliet Peter , Castellino Francis , Collen Désiré , Rosen Elliot 
Published: March 2018

SummaryMice with a total deficiency in blood coagulation Factor X (FX) were generated by targeted replacement of an 18-kb fragment of the FX gene, comprising all exons encoding the mature FX protein, with a neor
cassette. The genotype distribution among the offspring from heterozygous breeding pairs suggested that FX deficiency resulted in partial embryonic lethality, with approximately one-third of the FX
−/− embryos dying around embryonic day (E) 11.5-12.5. Two of 44 non-resorbed FX
−/− embryos analyzed at these stages showed signs of massive bleeding, one of which into the brain ventricles, but no histological defects in the vasculature of these embryos or their yolk sac were observed. The remainder of the FX
−/− embryos appeared normal and survived to term, but the majority of neonates (90%) died within 5 days, most frequently from intraabdominal bleeding. The remaining FX
−/− animals succumbed between postnatal day (P)5 and P20 with intraabdominal, subcutaneous, or intracranial bleeding or a combination thereof. The lethal phenotype of the FX
−/− mice illustrates the importance of FX function in embryonic and postnatal survival and demonstrates that these mice serve as effective models of the bleeding disorders observed in severe FX deficiency in humans.
Comparison of a Clinical Probability Estimate and Two Clinical Models in Patients with Suspected Pulmonary Embolism
Authors: Lijmer Jeroen , Mac Gillavry Melvin , Turkstra Franktien , Prins Martin , Büller Harry , Sanson Bernd-Jan ,   the ANTELOPE-Study Group
Published: March 2018

SummaryRecent studies have suggested that both the subjective judgement of a physician and standardized clinical models can be helpful in the estimation of the probability of the disease in patients with suspected pulmonary embolism (PE). We performed a multi-center study in consecutive in- and outpatients with suspected PE to compare the potential diagnostic utility of these methods. Of the 517 study patients, 160 (31%) were classified as having PE. Of these patients, 14% had a low probability as estimated by the treating physician, while 25 to 36% were categorized as having a low clinical probability with the use of two previously described clinical models. The objectively confirmed prevalence of PE in these three low probability categories was 19%, 28% and 28%, respectively. The three methods yielded comparable predictive values for PE in the other probability categories. We conclude that a physician’s clinical judgement alone and two standardized clinical models, although comparable, perform disappointingly in categorizing the pre-test probability in patients with suspected PE.
Outpatient Treatment of Pulmonary Embolism with Dalteparin
Authors: Anderson D. , Morrow B. , Gray L. , Touchie D. , Wells P. S. , Kovacs M. J. 
Published: March 2018

SummaryPulmonary embolism is a common complication of deep vein thrombosis. It has been established that low molecular weight heparin may be used to treat deep vein thrombosis or pulmonary embolism and randomized studies have established that outpatient management of deep vein thrombosis with low molecular weight heparin is at least as effective as in-hospital management with unfractionated heparin.This was a prospective cohort study of eligible patients with pulmonary embolism managed as outpatients using dalteparin (200 U/kg s/c daily) for a minimum of five days and warfarin for 3 months. Outpatients included those managed exclusively out of hospital and those managed initially for 1-3 days as inpatients who then completed therapy o out of hospital. Reasons for admission included hemodynamic instability; hypoxia requiring oxygen therapy; admission for another medical reason; severe pain requiring parenteral analgesia or high risk of major bleeding. Patients were followed for three months for clinically apparent recurrent venous thromboembolism and bleeding.Between three teaching hospitals, a total of 158 patients with pulmonary embolism were identified. Fifty patients were managed as inpatients and 108 as outpatients. Of the outpatients, 27 were managed for an average of 2.5 days as inpatients and then completed dalteparin therapy as outpatients. The remaining 81 patients were managed exclusively as outpatients with dalteparin. For all outpatients the overall symptomatic recurrence rate of venous thromboembolism was 5.6% (6/108) with only 1.9% (2/108) major bleeds. There were a total of four deaths with none due to pulmonary embolism or major bleed.This prospective study suggests that outpatient management of pulmonary embolism is feasible and safe for the majority of patients.
Inherited Thrombophilia as a Risk Factor for the Development of Ischemic Stroke in Young Adults
Authors: Voetsch Barbara , Damasceno Benito , Camargo Erica , Massaro Ayrton , Bacheschi Luiz , Scaff Milberto , Annichino-Bizzacchi Joyce , Arruda Valder 
Published: March 2018

SummarySeveral recent studies have analyzed a possible effect of thrombophilia risk factors such as factor V Leiden, the prothrombin variant (allele 20210 A), and homozygosity for thermolabile methylenetetrahydrofolate reductase (MTHFR-T) on the development of ischemic stroke (IS). In the present study, we determined the role of these prothrombotic polymorphisms in the early onset of arterial IS or cerebral venous thrombosis (CVT) in a group of young Brazilian adults of Caucasian and African descent.We conducted a cross-sectional study of 167 survivors of IS (153 patients with arterial IS and 14 cases of CVT; 66 men: 101 women; 124 of Caucasian and 43 of African origin; median age: 32.6 years; range: 15 to 45 years) and compared the prevalence of inherited thrombophilia risk factors with a control group of 225 sex and age matched individuals of the same ethnic background. To determine the interaction with atherogenic risk factors, the following diagnoses were considered: hypertension, hyperlipoproteinemia, diabetes mellitus, smoking status and use of oral contraceptives.In the arterial IS group, no significant variation was found between patients and controls of Caucasian origin regarding the prevalence of factor V Leiden (P = 0.92), the prothrombin variant (P = 0.13) or homozygosity for MTHFR-T (P = 0.61). Among Brazilians of African descent, 10.3%were homozygous for MTHFR-T, which was significantly elevated, odds ratio of 5.9 (95%CI: 0.88 to 49.15). In the CVT group, two Caucasian patients (20%) were heterozygous for the prothrombin variant, odds ratio of 9.7 (95%CI: 0.95 to 89.71) and one patient was carrier of factor V Leiden (P = 0.49). No prothrombotic polymorphism was identified in patients with CVT of African descent. All women in the CVT group were in use of oral contraceptives or in the post-partum stateInherited thrombophilia risk factors were not found to increase the risk of arterial IS among young patients of Caucasian descent. However, a potential role of homozygosity for MTHFR-T was observed in a small group of patients of African origin. The analysis of patients with CVT revealed an increased risk due to the prothrombin gene variant or oral contraceptive use. Further studies including all incoming patients with IS are necessary to evaluate the impact of inherited thrombophilia risk factors on early mortality.
Fast and Efficient Mutation Detection Method Using Multiplex PCR and Cycle Sequencing
Authors: Costa J. M. , Ernault P. , Vidaud D. , Vidaud M. , Meyer D. , Lavergne J. M. 
Published: March 2018

SummaryA method using multiplex PCR followed by cycle-sequencing has been developed to detect mutations in the FIX gene. The procedure was evaluated in 45 severe or mild haemophilia B patients from 45 unrelated families. At least one deleterious mutation was identified in every haemophiliac demonstrating the efficiency of the method. Furthermore the described procedure offers many advantages compared to other screening detection methods: it is fast (less than 48 h), simple (partly automated) and of relatively low cost (it requires only one PCR).
The Influence Exerted by a Restricted Phospholipid Microenvironment on the Expression of Tissue Factor Activity at the Cell Plasma Membrane Surface
Authors: Kunzelmann-Marche Corinne , Toti Florence , Zhang Youming , Nawroth Peter , Morrissey James , Freyssinet Jean-Marie , Satta Nathalie 
Published: March 2018

SummaryPhosphatidylserine (PhtdSer) is an anionic aminophospholipid necessary for the development of optimal tissue factor (TF) activity at the cell surface. This study investigates the implication of a restricted lipid environment with respect to PhtdSer availability on TF expression and activity. K562 cells, showing a reduced ability to externalize PhtdSer, were transfected with human TF cDNA. PhtdSer exposure and TF activity were examined in transfected cells and compared to monocytic THP-1 cells expressing constitutive and inducible TF or megakaryocytic HEL cells showing a high PhtdSer externalization potency. TF expression was evidenced by flow cytometry and its activity measured using functional assays. PhtdSer exposure was monitored by enzymatic prothrombinase assay. One clone (DC9) expressed a stable amount of TF antigen without global modification of its membrane status. Despite a noticeable TF expression level, clone DC9 presented only a weak TF activity even after ionophore stimulation. The apparent Km
, relative to factor X (FX) activation by TF-factor VIIa (FVIIa) complex, was 335 nM versus 70 nM for THP-1 cells. The velocity of the reaction was found 3-fold slower in DC9 than THP-1 cells. Ionophore treatment resulting in slightly enhanced amounts of available PhtdSer abolished this difference. The DC9 clone appears suitable for further investigations on the biology of TF expressed at the surface of cells where the contribution of PhtdSer is significantly attenuated. Such cells should enable further assessment of the role of TF as a receptor coupled to intracellular signaling pathways and its fate during apoptotic cell death.
Abbreviations: TF: tissue factor, FX: factor X, FVII(a): factor VII(a), PhtdSer: phosphatidylserine, PhtdCho: phosphatidylcholine, PhtdEth: phosphatidylethanolamine, BSA: bovine serum albumin, dcTF: des-cyto tissue factor (TF1-244: membrane-anchored TF lacking the cytoplasmic tail)
Thrombotic Variables and Risk of Idiopathic Venous Thromboembolism in Women Aged 45-64 Years
Authors: Woodward Mark , Vessey Martin , Rumley Ann , Gough Parimala , Daly Edel , Lowe Gordon 
Published: March 2018

SummaryHormone replacement therapy (HRT) has been shown to increase the relative risk of idiopathic venous thromboembolism (VTE) about threefold in several observational studies and one randomised controlled trial. Whether or not this relative risk is higher in women with underlying thrombophilia phenotypes, such as activated protein C (APC) resistance, is unknown. We therefore restudied the participants in a case-control study of the relationship between the use of HRT and the occurrence of idiopathic VTE in women aged 45-64 years. After protocol exclusions, 66 of the cases in the original study and 163 of the controls were studied. Twenty haematological variables relevant to risk of VTE were analysed, including thrombotic states defined from the literature. The relative risk of VTE showed significant associations with APC resistance (OR 4.06; 95% CI 1.62, 10.21); low antithrombin (3.33; 1.15, 9.65) or protein C (2.93; 1.06, 8.14); and high coagulation factor IX (2.34; 1.26, 4.35), or fibrin D-dimer (3.84; 1.99, 7.42). HRT use increased the risk of VTE in women without any of these thrombotic states (OR 4.09; 95% CI 1.26, 13.30). A similar effect of HRT use on the relative risk of VTE was also found in women with prothrombotic states. Thus for example, the combination of HRT use and APC resistance increased the risk of VTE about 13-fold compared with women of similar age without either APC resistance or HRT use (OR 13.27; 95% CI 4.30, 40.97).We conclude that the combination of HRT use and thrombophilias (especially if multiple) increases the relative risk of VTE substantially; hence women known to have thrombophilias (especially if multiple) should be counselled about this increased risk prior to prescription of HRT. However, HRT increases the risk of VTE about fourfold even in women without any thrombotic abnormalities: possible causes are discussed.
Analysis of Prothrombotic Effects of two Human Monoclonal IgG Antiphospholipid Antibodies of Apparently Similar Specificity
Authors: von Landenberg Christine , Barlage Stefan , Schmitz Gerd , Lackner Karl 
Published: March 2018

SummaryTwo human monoclonal antiphospholipid antibodies (APA) of the IgG type, HL-5B and RR-7F have been generated from a patient with primary antiphospholipid syndrome and recurrent cerebral microemboli (H.L.) and from a patient with SLE without evidence of recurrent thrombosis (R.R.). Both monoclonal APA have similar characteristics in ELISA tests. To further analyse the prothrombotic potential, their effect on human monocytes and platelets, and bovine aortic endothelial cells (BAEC) was investigated. Monocytes were isolated from buffy coats by standard techniques. They were incubated either with the respective monoclonal APA in different concentrations, or a control monoclonal IgG of the same subtype, or plasma of the patients, from whom the antibodies were isolated. Incubation with LPS served as positive control. BAEC were grown to confluence, and then incubated with the appropriate agonists. Procoagulant activity (PCA) was determined by a single stage clotting assay. PCA expression after incubation is given as the ratio of the coagulation times observed with media only divided by that observed with the agonist. A PCA ratio >1 indicates the induction of PCA by the agonist. At 1 µg/ml HL-5B yielded a PCA ratio of 1.63 ± 0.16 while RR-7F induced no significant rise to 1.06 ± 0.18. Dose response curves showed that RR-7F can induce PCA at higher concentrations. However, its effect is approx. 1/50 of HL-5B based on equimolar antibody concentration. Further analysis indicates that the majority of the PCA induced by monoclonal APA can be inhibited by a specific tissue factor antibody. Neither monoclonal antibody induced PCA in BAEC. Sera from both patients were able to induce PCA in monocytes. However, the PCA ratio of serum from H.L. was higher (1.78) than that of R.R. (1.44). Neither monoclonal APA had an effect on platelets as determined by flow cytometric analysis of CD62P, CD41, CD42b expression and fibrinogen binding with and without previous activation with 5 µM ADP or 15 µM TRAP-6. Similarly, there were no differences in platelet aggregation to different stimuli including submaximal activation. In summary, these data provide further evidence that induction of tissue factor in monocytes is one of the procoagulant effects of APA. Furthermore, the binding specificity of APA is perhaps not suited to predict the biological effects of the antibodies.