bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunological Assay for the Determination of Procarboxypeptidase U Antigen Levels in Human Plasma
Authors: Stromqvist Mats , Schatteman Katinka , Leurs Judith , Verkerk Robert , Andersson Jan-Olof , Johansson Thord , Scharpe Simon , Hendriks Dirk 
Published: March 2018

SummaryThe importance of carboxypeptidase U as a novel regulator of the fibrinolytic rate has attracted a lot of interest recently. In the present work, an ELISA was developed using polyclonal antibodies raised against recombinant proCPU, expressed in DON cells. The assay determines the antigen concentration of the zymogen of carboxypeptidase U, procarboxypeptidase U, in human citrated plasma or EDTA plasma. No interference is observed with plasma carboxypeptidase N. The assay is very reproducible (within-run: 4.6% CV, between-run: 6.8% CV). In a group of 479 healthy individuals the mean proCPU antigen concentration is 13.4 μg/ml (SD 2.5 μg/ml). A good correlation is found with the functional procarboxypeptidase U assay described earlier (r = 0.82, p <0.0001) (Schatteman K, Goossens F, Scharpé S, Neels H, Hendriks D Clin Chem 1999; 45: 807-813). The significant correlation between the proCPU antigen concentration and the 50% clot lysis time stresses its importance as a player in fibrinolysis control.
Abbreviations: CPU, carboxypeptidase U; proCPU, procarboxypeptidase U; TAFI, thrombin activatable fibrinolysis inhibitor; AP, alkaline phosphatase; EDTA, ethylenediamine tetra-acetic acid; Tris, tris-(hydroxyethyl)-aminomethane; PPACK, phenylalanyl-prolyl-chloromethyl ketone; SP, sulphopropyl; HEPES, N-2-hydroxyethylpiperazine-N’-ethanesulfonic acid
Circulating Procoagulant Microparticles in Women with Unexplained Pregnancy Loss: a New Insight
Authors: Laude I. , Rongières-Bertrand C. , Boyer-Neumann C. , Wolf M. , Mairovitz V. , Hugel B. , Freyssinet J. M. , Frydman R. , Eschwège V. , Meyer D. 
Published: March 2018

SummaryOne of the frequently proposed mechanisms for pregnancy losses refers to uteroplacental thrombosis. However the contribution of classical thrombotic risk factors remains questionable and, if real, does not account for a large number of pregnancy losses. The aim of this study was to investigate the presence of circulating procoagulant microparticles, a new marker of cell activation already associated with various prothrombotic clinical settings. Microparticles were assessed by an original prothrombinase assay on platelet depleted plasma obtained from 74 women with a history of pregnancy loss without apparent cause and 50 controls. Patients were studied at least 2 months after the last obstetrical event and were classified into 2 groups: 49 women with at least 3 consecutive spontaneous abortions at or before the 10th postmenstrual week and 25 with at least one fetal death beyond the 10th postmenstrual week. Among the 74 patients, 41 had increased levels of circulating microparticles, 29 belonging to the group of early pregnancy loss (59%) and 12 to the group of late pregnancy loss (48%). The high prevalence of increased levels of procoagulant microparticles in both groups makes this new marker very promising for the understanding, follow up and therapeutical handling of pregnancy loss.
Mechanism of the Immune Response to Human Factor VIII in Murine Hemophilia A
Authors: Wu Huiyun , Reding Mark , Qian Jiahua , Okita David , Parker Ernie , Lollar Pete , Hoyer Leon , Conti-Fine Bianca 
Published: March 2018

SummaryMice genetically deficient in factor VIII (fVIII) are a model of hemophilia A. As a first step to reproduce in this mouse model what occurs over time in hemophilia A patients treated with human fVIII (hfVIII), we have investigated the time course and the characteristics of their immune response to hfVIII, after multiple intravenous injections. Anti-hfVIII antibodies appeared after four to five injections. They were IgG1 and to a lesser extent IgG2, indicating that they were induced by both Th2 and Th1 cells. Inhibitors appeared after six injections. CD4+ enriched splenocytes from hfVIII-treated mice proliferated in response to fVIII and secreted IL-10: in a few mice they secreted also IFN-γ and in one mouse IL-4, but never IL-2. A hfVIII-specific T cell line derived from hfVIII-treated mice secreted both IL-4 and IFN-γ, suggesting that it included both Th1 and Th2 cells. CD4+ enriched splenocytes of hfVIII-treated mice recognized all hfVIII domains. Thus, hemophilic mice develop an immune response to hfVIII administered intravenously similar to that of hemophilia A patients. Their anti-hfVIII antibodies can be inhibitors and belong to IgG subclasses homologous to those of inhibitors in hemophilic patients; their anti-hfVIII CD4+ cells recognize a complex repertoire and both Th1 and Th2 cytokines, and especially IL-10, may drive the antibody synthesis.
Abbreviations used: antibodies, Ab; antigen presenting cells, APC; Arbitrary Units, AU; enzyme-linked immunosorbant assay, ELISA; factor VIII, fVIII; human factor VIII, hf VIII; intravenous, i.v.; optical density, OD; polymerase chain reaction, PCR; phosphate buffered saline solution, PBS; PBS containing 3% bovine serum albumin, PBS/BSA; PBS containing 0.05% polyoxyethylene sorbitan monolaurate, PBS/Tween-20; phytohemoagglutinin, PHA; stimulation index, SI
Serum Prostaglandin D Synthase Level after Coronary Angioplasty May Predict Occurrence of Restenosis
Authors: Takayanagi Kan , Morooka Shigenori , Uehara Yoshio , Oda Hiroshi , Seiki Kousuke , Nakajima Hiroshi , Urade Yoshihiro , Inoue Teruo 
Published: March 2018

SummaryLipocalin-type prostaglandin D synthase (L-PGDS), which is responsible for the biosynthesis of PGD2, has recently been found to be present in the atherosclerotic plaque of the human coronary artery and also to be secreted in human serum. We measured the serum L-PGDS level and compared it with the expressions of the platelet membrane surface glycoprotein and neutrophil adhesion molecule in patients undergoing PTCA. The L-PGDS level significantly decreased (P < 0.01) and the platelet surface expression of CD62P (P-selectin) significantly increased (P < 0.01) immediately after PTCA in the coronary sinus blood. Both changes were inversely correlated (R = −0.72, P < 0.001). Although the L-PGDS level in the coronary sinus blood remained equivalent to the baseline level in patients who experienced restenosis, the level increased over the baseline level (P < 0.01) at 48 h after PTCA in patients without restenosis. Neutrophil surface expression of CD11b (a subunit of Mac-1) significantly increased at 24 h (P < 0.01) to 48 h (P < 0.001) after PTCA in the coronary sinus blood in patients with restenosis but the change showed less significant in patients without restenosis. The changes in the L-PGDS level and the CD11b expression at 48 h after PTCA were inversely correlated (R = −0.55, P < 0.05). An increased serum L-PGDS level at 48 h after PTCA possibly predicts the avoidance of late restenosis. It is suggested that reduction in PGD2 synthesis triggers platelet activation and that a subsequent increase in the PGD2 synthesis suppresses inflammatory reaction at the intervention site indicated by neutrophil activation and inhibits development of restenosis. Pharmacological or biological intervention that increases endogenous PGD2 synthesis should be tested as a new strategy to prevent restenosis.
Recombinant Factor IX Recovery and Inhibitor Safety: A Canadian Post-licensure Surveillance Study
Authors: Lillicrap David , Hensman Caroline , Card Robert , Scully Mary-Frances , Poon Man-Chiu ,   Members of Asso cia tion of Hemophilia Clinic Directors of Canada* and Canadian Association of Nurses in Hemophilia Care*
Published: March 2018

SummaryAs part of the Canadian post-licensure surveillance on the safety of recombinant factor IX (rFIX, BeneFIX®), factor IX recovery and inhibitor development were studied. The recovery following rFIX infusion in 126 patients (mean = 0.77, median 0.72, range 0.36-1.85, 95% CI of mean 0.74-0.81, expressed as FIX activity increase in U/dL per IU FIX concentrate/kg body weight infused) was significantly lower than that following the last plasma-derived factor IX (pdFIX) infusion in 74 patients (mean 1.05, median 1.00, range 0.37-2.29, 95% CI of mean 0.99-0.97). The recovery for rFIX for patients aged ≤15 years (n = 41, mean recovery 0.64) and that for patients aged >15 years (n = 85, mean 0.84) was each significantly lower than that for pdFIX (aged ≤15 years: n = 21, mean recovery 0.91; aged >15 years: n = 53, mean recovery 1.10). For both rFIX and pdFIX concentrates, the recovery was lower in patients ≤15 years of age compared to those >15 years of age. Similar data and conclusions were obtained on 66 patients with paired recovery data from rFIX and pdFIX. Overall, our data are similar to those obtained in formal clinical trials. Two of 244 patients treated with rFIX for up to 5 years have developed de novo inhibitors associated with anaphylaxis, an incidence that is similar to that reported for pdFIX. No other serious adverse events, including thrombotic episodes, were reported. To the best of our knowledge, this is the first formal report of recovery and inhibitor formation on rFIX in a peer-reviewed manuscript form.
Plasminogen Has a Broad Extrahepatic Distribution
Authors: Seiffert Dietmar , Fowler Bruce , Jenkins George , Thinnes Therese , Loskutoff David , Parmer Robert , Miles Lindsey , Zhang Lu 
Published: March 2018

SummaryPlasmin is the major enzyme that dissolves fibrin in the vasculature and the predominant source of its zymogen, plasminogen, is liver. However, plasmin has a broad substrate spectrum and, if present in other tissues, may perform additional functions. We tested the hypothesis that plasminogen is expressed broadly extrahepatically. A sensitive and specific isotopic quantitative RT-PCR assay was developed to detect plasminogen mRNA from total RNA isolated from C57BL/6J mice tissues. Plasminogen mRNA was detected in adrenal, kidney, brain, testis, heart, lung, uterus, spleen, thymus and gut. Of these tissues, adrenal had the highest plasminogen mRNA content. In situ hybridization was utilized to localize plasminogen mRNA expressing cell types. Besides hepatocytes, positive cells were identified in both adrenal and kidney medullae and cortexes. Plasminogen mRNA expression was detected in cerebral, hippocampal and cerebellar neurons. Plasminogen mRNA was detected in cells in early stages of spermatogenesis in testis, present in the cortex and medulla of the thymus and in splenic white and red pulps. Our results suggest that the plasminogen gene is expressed broadly in extrahepatic tissues. Thus, tissues separated by local anatomic barriers as well as tissues accessible to circulating plasminogen have the capacity to provide local sources of plasminogen.
Comparison of Venography and Ultrasound for the Diagnosis of Asymptomatic Deep Vein Thrombosis in the Upper Body in Children
Authors: Male Christoph , Chait Peter , Ginsberg Jeffrey , Hanna Kim , Andrew Maureen , Halton Jacqueline , Anderson Ron , McCusker Patricia , Wu John , Abshire Thomas , Cherrick Irene , Mahoney Donald , Mitchell Lesley 
Published: March 2018

SummaryDeep vein thrombosis (DVT) in children occurs primarily in the upper body venous system. This prospective diagnostic study compared bilateral venography and ultrasound for detection of DVT in the upper venous system in 66 children with acute lymphoblastic leukemia. Results were interpreted by central blinded adjudication.Deep venous thrombosis occurred in 29% (19/66) patients. While 15/19 DVT were detected by venography (sensitivity 79%), only 7/19 were detected by ultrasound (sensitivity 37%). The 12 DVT detected by venography but not by ultrasound were located in the subclavian vein or more central veins. Three of 4 DVT detected by ultrasound but not by venography were in the jugular vein. We conclude that ultrasound is insensitive for DVT in the central upper venous system but may be more sensitive than venography in the jugular veins. A combination of both venography and ultrasound is required for screening for DVT in the upper venous system.
Decreased Concentrations of Heparinoids Are Required to Inhibit Thrombin Generation in Plasma from Newborns and Children Compared to Plasma from Adults due to Reduced Thrombin Potential
Authors: Berry Leslie , Monagle Paul , Andrew Maureen , Chan Anthony 
Published: March 2018

SummaryThrombin generation is decreased and delayed in plasma from newborns and children compared to adults. We hypothesized that lower doses of heparinoid anticoagulants are required to give similar thrombin generation in newborn (umbilical cord) and child plasmas compared to that of adults. Thrombin generation was performed in either the absence or presence of unfractionated heparin (UFH), low molecular weight heparin (LMWH) or a covalent antithrombin-heparin complex (ATH). After contact activation and recalcification of each plasma, thrombin activity was measured by periodic sub-sampling into chromogenic substrate. UFH inhibited thrombin generation to a greater extent compared to LMWH in all plasmas. Cord plasma was more sensitive to inhibition and displayed a greater difference in the effectiveness of UFH compared to LMWH than other plasmas. Lower concentrations of UFH and LMWH were required to inhibit thrombin generation in cord and child plasmas compared to adult plasma. In comparison, ATH strongly inhibited thrombin generation in all 3 plasmas. Similar peak thrombin concentrations were observed at lower ATH concentrations (0.1 U/mL) compared to either UFH (0.25 U/mL) or LMWH (0.25 U/mL). As with UFH and LMWH, cord plasma was more sensitive to inhibition by ATH than the other plasmas and lower ATH concentrations inhibited thrombin generation in cord and child plasmas compared to adult plasma. Decreased thrombin generation with heparinoids in cord and child plasmas compared to adult plasma coincided with decreased rates of prothrombin consumption and increased proportion of thrombin- α2-macroglobulin inhibitor complexes. In summary, lower doses of UFH, LMWH or ATH result in similar peak thrombin generation in newborn and child plasmas compared to adult plasma. Cord plasma was the most sensitive to inhibition, with ATH being more effective than UFH or LMWH.
Internal Quality Control of PCR-based Genotyping Methods in Research Studies and Patient Diagnostics
Authors: Gram Jørgen , Jespersen Jørgen , de Maat Moniek , Bladbjerg Else-Marie 
Published: March 2018

SummaryGenetic analyses are increasingly integrated in the clinical laboratory, and internal quality control programmes are needed. We have focused on quality control aspects of selected polymorphism analyses used in thrombosis research. DNA was isolated from EDTA-blood (n = 500) by ammonium acetate precipitation and analysed for 18 polymorphisms by polymerase chain reaction (PCR), i. e. restriction fragment length polymorphisms, allele specific amplification, or amplification of insertion/deletion fragments. We evaluated the following aspects in the analytical procedures: sample handling and DNA-isolation (pre-analytical factors), DNA-amplification, digestion with restriction enzymes, electrophoresis (analytical factors), result reading and entry into a database (post-analytical factors). Furthermore, we evaluated a procedure for result confirmation. Isolated DNA was of good quality (42 µ.g/ml blood, A260/A280 ratio >1.75, negative DNAsis tests), and the reagent blank was contaminated in <1% of the results. Occasionally, results were re-analysed because of positive reagent blanks (<1%) or because of problems with the controls (< 5%). On confirmation, we observed 4 genotyping discrepancies. Control of data handling revealed 0.1% reading mistakes and 0.5% entry mistakes. Based on our experiences we propose an internal quality control programme for widely used PCR-based haemostasis polymorphism analyses.
Dosing in Heavy-weight/Obese Patients with the LMWH, Tinzaparin: A Pharmacodynamic Study
Authors: Barrett Jeffrey , Assaid Christopher , Fossler Michael , Cox Donna , Leathers Todd , Leese Philip , Hainer James 
Published: March 2018

SummaryThis pharmacodynamic study examined weight-based dosing of the low molecular weight heparin (LMWH), tinzaparin, in heavyweight/obese subjects. Single doses (175 and 75 IU/kg) were administered subcutaneously (SC) to 37 healthy heavy-weight subjects (101-165 kg; 26-61 kg/m2). AUA and Amax values of anti-Xa and anti-IIa activities were consistent over these body weight and body mass index (BMI) ranges, indicating that tinzaparin pharmacodynamics are not influenced by body weight or BMI. The range of AUA and Amax values in the study population overlapped that of historical control normal-weight subjects (<100 kg), indicating that weightadjusted tinzaparin dosing yields a predictable response regardless of body weight or BMI. Tinzaparin was well tolerated, although injection site bruising was commonly reported. SC tinzaparin dosing in heavy or obese patients is appropriate based on body weight alone; the dose need not be capped at a maximal absolute dose.
Pharmacokinetics of Recombinant Factor IX after Intravenous and Subcutaneous Administration in Dogs and Cynomolgus Monkeys
Authors: McCarthy K. , Stewart P. , Sigman J. , Read M. , Keith J. C. , Brinkhous K. M. , Nichols T. C. , Schaub R. G. 
Published: March 2018

SummaryHemophilia B therapy requires intravenous (IV) infusions of large volumes of factor IX due to the low concentration of factor IX in concentrates (∼100 IU/mL). High concentration recombinant factor IX (rFIX) could be a significant advance since it would reduce the large volumes necessary for IV dosing and allow for low-volume subcutaneous (SC) administration. To evaluate high concentration factor IX, we produced formulations with either 2,000 or 4,000 IU/mL and studied the SC bioavailability in beagle dogs, cynomolgus monkeys and hemophilia B dogs along with efficacy in hemophilia B dogs. Beagle dog SC bioavailability was 86.4% using a 2000 IU/mL formulation and 77.0% using a 4000 IU/mL formulation. Monkey bioavailability of a 4000 IU/mL formulation of rFIX was 34.8%. A single SC administration of 200 IU/kg (4000 IU/mL) of rFIX to hemophilia B dogs, produced factor IX clotting activity above 5% for 5 days with a bioavailability of 48.6%. High concentration SC rFIX has an acceptable pharmacokinetic profile in monkeys and dogs, and produces a sustained FIX activity in hemophilic dogs.
Tirofiban Blocks Platelet Adhesion to Fibrin with Minimal Perturbation of GpIIb/IIIa Structure
Authors: Stahle Mary , Jerome Gray , Nagaswami Chandrasekaran , Weisel John , Hantgan Roy 
Published: March 2018

SummaryA biophysical approach tested the hypothesis that tirofiban, like eptifibatide, perturbs GpIIb/IIIa structure. Tirofiban bound tightly to platelet GpIIb/IIIa (EC50 ∼ 24 nmol/L) and effectively inhibited platelet aggregation (IC50 ∼ 37 nmol/L) but blocked platelet adhesion to clotted fibrin only at much higher doses (IC50 ∼ 580 nmol/L). Electrophoretic analyses demonstrated that tirofiban protected GpIIb/IIIa from SDSinduced subunit dissociation. However, saturating tirofiban concentrations had little or no effect on GpIIb/IIIa secondary or tertiary structure, as determined by circular dichroic spectroscopy, dynamic light scattering, and sedimentation velocity measurements performed with purified receptors in octyl glucoside. Moderate dose-dependent effects on GpIIb/IIIa quaternary structure were detected by sedimentation equilibrium. Transmission electron microscopy showed minimal tirofiban-induced receptor activation or oligomerization. Thus, even at the increased concentrations needed to block platelet:fibrin adhesive interactions, tirofiban exhibited only limited effects on GpIIb/IIIa conformation and clustering. Our results provide new insights into the mechanisms and potential prothrombotic complications of integrin antagonists.
Genome-wide linkage analysis of von Willebrand factor plasma levels: results from the GAIT project
Authors: Almasy Laura , Manuel Soria Jose , Buil Alfonso , Stone William , Lathrop Mark , Blangero John , Fontcuberta Jordi , Carlos Souto Juan 
Published: March 2018

SummaryHigh plasma levels of von Willebrand factor (vWF) have been associated with the risk of thromboembolic disease. As a complex trait, this phenotype must be influenced by genetic and environmental factors. Among the genetic factors, only the ABO gene located on chromosome 9q34 has been clearly linked to the plasma levels of vWF. This locus explains about 30-40% of the genetic variability. Therefore, the source of the majority of the genetic component remains to be identified.To search for these unknown loci, we conducted a genome-wide linkage screen for genes affecting normal variation in vWF levels in 21 Spanish families as part of the GAIT (Genetic Analysis of Idiopathic Thrombophilia) Project.The results showed that the strongest linkage signal (LOD = 3.46, p = 0.00003) for vWF was found on chromosome 9q34 at the DNA marker D9S290, where the ABO gene is located. Additional suggestive linkage signals were found on chromosomes 2q23.2 (LOD = 1.65, p = 0.003) and 1p36.13 (LOD = 1.32, p = 0.007). After refining the linkage analysis, conditional to the ABO genotype, three additional loci on chromosomes 5, 6 and 22 showed LOD scores higher than 1, suggesting the presence of other genes linked to vWF levels. Curiously, no linkage signals were detected in other chromosome regions previously associated with vWF levels (like the structural VWF gene on 12p13.2 or Lewis blood group gene on 19q13). These results indicate that these loci are not important genetic determinants of the normal variation of vWF levels.Our results indicate that the ABO locus is the major genetic determinant of the plasma levels of the vWF in Spanish population. It is possible that there are other potential regions on chromosomes 1, 2, 5, 6 and 22 that influence this thrombosis risk factor. However, the structural vWF gene itself has a very low influence (if any) on the plasma levels of vWF.
Circulating microparticles: a marker of procoagulant state in normal pregnancy and pregnancy complicated by preeclampsia or intrauterine growth restriction
Authors: Bretelle Florence , Sabatier Florence , Desprez Dominique , Camoin Laurence , Grunebaum Leila , Combes Valérie , D’Ercole Claude , Dignat-George Françoise 
Published: March 2018

SummaryIn the present study, we explored the microparticles involved in the control of hemostatic equilibrium, i.e microparticles originating from platelet, endothelial cells and total MP defined as annexin V positive microparticles. Our aim was to analyze the level and procoagulant activity of these microparticles in normal pregnancy and pregnancies complicated with preeclampsia or isolated intrauterine growth restriction. We reported increased levels of platelet and endothelial microparticles in normal pregnancy compared to non pregnant healthy women. Number of annexin V microparticles was significantly increased together with their procoagulant activity. In pathological pregnancies, significant reduction in platelet microparticle number was found in preeclampsia. The procoagulant activity generated by the total annexin V MP was unchanged, suggesting that the microparticles remaining in the circulation were pro-coagulant. This study evidenced that microparticles constitute a cellular marker of a proinflammatory and procoagulant responses in normal pregnancy. In pregnancies with vascular complications, circulating MP with procoagulant potential may be part of the exacerbation of these responses.