bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Role of a Decision Rule in Symptomatic Pulmonary Embolism Patients with a Non-high Probability Ventilation-perfusion Scan
Authors: Michel Bowine C , Kuijer Philomeen M M , McDonnell Joseph , Beek Edwin J R van , Rutten Frans F H , Büller Harry R 
Published: July 2018

Summary
Background: In order to improve the use of information contained in the medical history and physical examination in patients with suspected pulmonary embolism and a non-high probability ventilation-perfusion scan, we assessed whether a simple, quantitative decision rule could be derived for the diagnosis or exclusion of pulmonary embolism. Methods: In 140 consecutive symptomatic patients with a non- high probability ventilation-perfusion scan and an interpretable pulmonary angiogram, various clinical and lung scan items were collected prospectively and analyzed by multivariate stepwise logistic regression analysis to identify the most informative combination of items. Results: The prevalence of proven pulmonary embolism in the patient population was 27.1%. A decision rule containing the presence of wheezing, previous deep venous thrombosis, recently developed or worsened cough, body temperature above 37° C and multiple defects on the perfusion scan was constructed. For the rule the area under the Receiver Operating Characteristic curve was larger than that of the prior probability of pulmonary embolism as assessed by the physician at presentation (0.76 versus 0.59; p = 0.0097). At the cut-off point with the maximal positive predictive value 2% of the patients scored positive, at the cut-off point with the maximal negative predictive value pulmonary embolism could be excluded in 16% of the patients. Conclusions: We derived a simple decision rule containing 5 easily interpretable variables for the patient population specified. The optimal use of the rule appears to be in the exclusion of pulmonary embolism. Prospective validation of this rule is indicated to confirm its clinical utility.
Physical Activity, Fibrinogen Plasma Level and Gene Polymorphisms in Postmenopausal Women
Authors: Rauramaa Rainer , Väisänen Sari , Nissinen Aulikki , Rankinen Tuomo , Penttilä IIkka , Saarikoski Seppo , Tuomilehto Jaakko , Gagnon Jacques , Pérusse Louis , Bouchard Claude 
Published: July 2018

SummaryThe relations between habitual physical activity (PA), fibrinogen gene polymorphisms and plasma fibrinogen were investigated in 191 postmenopausal women. Subjects who reported PA at least 4 times/ week had lower fibrinogen level (3.19 g/1; 95% Cl 3.10; 3.27) than women reporting PA 2-3 times/week (3.43 g/1; 3.29; 3.58) or sedentary subjects (3.64 g/1; 3.33; 3.94). There were no differences in plasma fibrinogen across the α-fibrinogen (Rsal, TaqI) or (β-fibrinogen (Mnll, Bell, Hindlll) genotypes, the frequencies of which were in a Hardy- Weinberg equilibrium. An interaction between Rsal, which was in complete linkage disequilibrium with TaqI, and PA on plasma fibrinogen was observed, even after adjustments for BMI, smoking and medication (p = 0.024). Among women homozygous for the common Rsal allele, the physically most active had lower fibrinogen level (p <0.001) compared to the physically less active subjects. These results suggest that, in postmenopausal women, the relation between physical activity and plasma fibrinogen is modulated by genetic variation in the α-fibrinogen gene.
Heat Stability of Two Candidate International Reference Preparations for Recombinant Human Tissue Factor
Authors: Besselaar A M H P van den , Rijn C J J van , Taberner D A , Goodman L J , Poller L , Clarke K 
Published: July 2018

SummaryAdequate heat stability of international reference preparations (IRP) for thromboplastin (tissue factor) is an essential requirement. Accelerated degradation testing was performed by three laboratories on two candidate IRP for recombinant human tissue factor.Heat treatment of these candidates resulted in slight shortening of the PT, contrasting with heat-induced prolongation of the PT observed with a conventional human brain derived IRP.Heat stability of these candidates was improved when compared with the stability of previous recombinant human tissue factor preparations.The PT-ratio did not change significantly when the candidates were stored for 28 days at 44° C. It’ can therefore be concluded that both candidates are acceptable with regard to stability.
The Migration of Human Smooth Muscle Cells In Vitro Is Mediated by Plasminogen Activation and Can Be Inhibited by α2-Macroglobulin Receptor Associated Protein
Authors: Wijnberg Monique J , Quax Paul H A , Nieuwenbroek Nancy M E , Verheijen Jan H 
Published: July 2018

SummaryThe plasminogen activation system is thought to be important in cell migration processes. A role for this system during smooth muscle cell migration after vascular injury has been suggested from several animal studies. However, not much is known about its involvement in human vascular remodelling. We studied the involvement of the plasminogen activation system in human smooth muscle cell migration in more detail using an in vitro wound assay and a matrix invasion assay. Inhibition of plasmin activity or inhibition of urokinase-type plasminogen activator (u-PA) activity resulted in approximately 40% reduction of migration after 24 h in the wound assay and an even stronger reduction (70-80%) in the matrix invasion assay. Migration of smooth muscle cells in the presence of inhibitory antibodies against tissue-type plasminogen activator (t-PA) was not significantly reduced after 24 h, but after 48 h a 30% reduction of migration was observed, whereas in the matrix invasion assay a 50% reduction in invasion was observed already after 24 h. Prevention of the interaction of u-PA with cell surface receptors by addition of soluble u-PA receptor or α2-macroglobulin receptor associated protein (RAP) to the culture medium, resulted in a similar inhibition of migration and invasion. From these results it can be concluded that both u-PA and t-PA mediated plasminogen activation can contribute to in vitro human smooth muscle cell migration and invasion. Furthermore, the interaction between u-PA and its cell surface receptor appears also to be involved in this migration and invasion process. The inhibitory effects on migration and invasion by the addition of RAP suggests an involvement of a RAP sensitive receptor of the LDL receptor family, possibly the LDL-receptor related protein (LRP) and/or the VLDL receptor.
Activation of Human Platelets Causes Post-translational Modifications to Cytoplasmic Dynein
Authors: Rothwell Stephen W , Calvert Valerie S 
Published: July 2018

SummaryIn our studies of human platelets we have detected the presence of the molecular motors kinesin and dynein. Dynein is present at a concentration (0.8 μg/g tissue) that is approximately 1/3 the concentration reported for neuronal tissue. Immunofluorescence microscopy of resting platelets shows that, while platelet microtubules are arranged in coiled hoops forming the marginal band in the cortical region of the platelet, dynein is distributed in a pattern of punctate staining throughout the cytoplasm of the platelets. Fractionation of unactivated platelets shows that dynein partitions to the soluble fraction. Stimulation of platelets with thrombin, ADP or epinephrine causes a partial translocation of dynein from the soluble fraction to the particulate fraction with thrombin being the most efficient agent at promoting this shift. Dynein intermediate chain recovered in the soluble fraction of disrupted platelets following activation displays a transient, time-dependent phosphorylation. In contrast, dynein intermediate chain recovered in the particulate fraction shows decreased phosphorylation. These results indicate that human platelets contain a complex microtubule-based system of motor proteins that is an integral part of the physiological changes occurring during platelet activation.
Plasma Derived von Willebrand Factor Preparations: Collagen Binding and Ristocetin Cofactor Activities
Authors: Chang Ping , Aronson D L 
Published: July 2018

SummaryFive plasma preparations (11 lots) used in the treatment of von Willebrand’s disease (vWD) were evaluated. The collagen binding function of von Willebrand factor (vWF) containing preparations was compared with the ristocetin cofactor activity and the vWF antigen. Some preparations have higher ratio of functional activity (ristocetin cofactor and collagen binding) relative to the antigen than is found in normal plasma. The ristocetin cofactor activity and the collagen binding activity are tightly correlated (r = .95). Ultracentrifugal (UCF) analysis was used to compare the size distribution of vWf antigen, ristocetin cofactor and collagen binding activity. The sedimentation of all of the vWF parameters in the plasma products was slower than in plasma. In plasma products the ristocetin cofactor activity sediments the most rapidly, the collagen binding activity is slower and the antigen the slowest. The collagen/antigen ratio decreases with decreasing vWF size. Assignment of potency to vWF containing preparations utilizing the collagen binding activity may be more precise and as accurate as with the traditional ristocetin cofactor assay.
Endothelium-derived Nitric Oxide Decreases Polymorphonuclear Leukocyte Interaction with the Deeply Injured Arterial Wall under Intermediate and High Shear Conditions
Authors: Provost Patrick , Merhi Yahye 
Published: July 2018

SummaryPrevious studies have shown that nitric oxide (NO) inhibits specific agonist-induced polymorphonuclear leukocyte (neutrophil) and platelet aggregation in vitro. However, the inhibitory effects of NO on neutrophil interaction with the deeply injured arterial wall under conditions of flow is unknown. Therefore, we investigated the influence of NO derived from the endothelium on neutrophil and platelet interactions with the downstream arterial media under controlled flow conditions. Porcine aortic media, simulating deep arterial wall injury, was exposed to flowing porcine non-anticoagulated arterial blood for 5 min at intermediate (1006 s1) and high (3397 s1) shear conditions, and deposition of radiolabeled neutrophils and platelets was quantified. Neutrophil deposition on the exposed arterial media was reduced, by more than 30%, by pretreatment of the endothelium with the physiological precursor of NO, L-arginine, from 84.1 ± 13.7 to 57.4 ± 7.2 X 103/cm2 (p < 0.05) at 1006 s*1, and from 99.3 ± 9.8 to 65.5 ± 8.7 X KP/cm2 (p < 0.05) at 3397 s1 of shear rate, relative to control. Pretreatment of the endothelium with the inactive stereoisomer D-arginine had no effect on neutrophil deposition. These specific inhibitory effects of L-arginine were completely abolished by the inhibitor of NO synthesis, N^-nitro- L-arginine methyl ester (l-NAME) at both shear rates. Endothelial pretreatment with D-arginine, or with L-arginine, in the absence or presence of l-NAME, did not significantly influence platelet interaction with the thrombogenic arterial media at intermediate and high shear rates. These results indicate that NO derived from the endothelium can modulate and has a greater influence on neutrophil, than on platelet, interaction with the injured arterial wall exposing the media under conditions of flow typical to moderately and severely stenosed arteries.
Coagulation Factor VII, Serum-Triglycerides and the R/Q353 Polymorphism: Differences between Older Men and Women
Authors: Mennen Louise I , de Maat Moniek P M , Schouten Evert G , Kluft Cornelis , de Jong Paulus T V. M , Hofman Albert , Grobbee Diederick E 
Published: July 2018

SummaryCoagulation factor VII activity (FVIIC) is a risk indicator for cardiovascular disease. It is related to serum-triglycerides and the R/Q353 polymorphism (alleles R and Q) in the gene coding for factor VII is strongly associated with factor VII. The association of serum- triglycerides with factor VII may differ between the genotypes, but the results of earlier studies were inconsistent and did not include older people. We studied FVII, triglycerides and the R/Q353 polymorphism in the Rotterdam Study.In 1158 older subjects (489 men and 669 women) FVIIC, factor VII: Chr, serum-triglycerides and the R/Q353-genotype were determined.In women triglycerides were positively associated with FVIIChr and FVIIC (FVIIChr: β = 12.4 % PP/mmol/L, CI: 10.3-14.5; FVII:C: β = 13.1% PP/mmol/L, CI: 10.4-15.8). These associations varied by genotype (FVII:Chr: RR: β = 11.7, CI: 9.6-13.8, RQ/QQ: β = 7.9, CI: 4.6-11.2; FVII:C: RR: β = 12.5, CI: 9.5-15.5, RQ/QQ: β = 6.4, CI: 1.4-11.4).In men, the associations of FVII:Chr and FVII:C with triglycerides were weaker (FVII:Chr: β = 5.9, CI: 4.1-7.7; FVII:C: β = 8.7, CI: 6.2-11.2). There was no difference between the genotype groups.These results suggest that only in older women the strength of the association of factor VII with serum-triglycerides varies according to genotype of the R/Q353 polymorphism.
Use of Modified Functional Assays for Activated Protein C Resistance in Patients with Basally Prolonged aPTT
Authors: Montaruli Barbara , Schinco Piercarla , Pannocchia Antonella , Giorgianni Angelica , Borchiellini Alessandra , Tamponi Giacomo , Pileri Alessandro 
Published: July 2018

SummaryInherited resistance to activated protein C (APCr) is currently recognized as the most prevalent cause underlying venous thrombophilia, with an estimated prevalence around 20% in thrombotic patients and around 1.8-7% in the general population. A correct laboratory diagnosis of APCr is therefore essential. Two different diagnostic approaches are at present at our disposal: the semi-quantitative plasma test based on the measurement of two aPTTs (in the presence and absence of activated protein C), and the detection of the factor V Arg506 GIn mutation by DNA analysis.In this study we firstly evaluated sensitivity, specificity and diagnostic efficiency of an aPTT-based plasma clotting test (Chromogenix, Sweden) versus DNA analysis; then, since the APC resistance test is invalidated by a basally prolonged aPTT (i.e. during warfarin and heparin therapy or in patients with clotting factor deficiencies or in the presence of a lupus anticoagulant), patient plasmas were conveniently diluted in factor V deficient plasma in order to correct clotting factor abnormalities. Nevertheless, patients with a LA and an aPTT ratio range 1.8-3.17 were still all misclassified. We obtained correct diagnoses in LA positive patients by preincubating plasmas with a mixture of phospholipids; therefore we decided to perform a double modified clotting test adding a mixture of platelet derived phospholipids to samples previously diluted in factor V deficient plasma. The performance characteristics of this novel method with a different aPTT reagent (Behring, Germany) were also evaluated. With this double modified test all patients were correctly classified as negative or positive for factor V mutation in agreement with DNA analysis, irrespectfully of the basal aPTT value and the aPTT reagent employed. We propose this modified version of the APCr clotting test as an easily reproducible, reliable, very sensitive and specific screening test which possibly reduces the need for DNA analysis.
Characterization and Targeting of the Murine α2-Antiplasmin Gene
Authors: Okada K , Lijnen H R , Dewerchin M , Belayew A , Matsuo O , Collen D , Bernaerts R 
Published: July 2018

Summaryα2-Antiplasmin (α2-AP) is the main physiological plasmin inhibitor in mammalian plasma. As a first step toward the generation of α2-AP deficient mice, the murine α2-AP
1 gene was characterized and a targeting vector for homologous recombination in embryonic stem (ES) cells constructed. Alignment of nucleotide sequences obtained from genomic subclones allowed location of exons 2 through 10 of the α2-AP 1gene, but failed to identify the 5’ boundary of exon 1. Compared to the human gene, exons 2 through 9 in the murine gene have identical size and intron-exon boundaries obeying the GT/AG rule. The 5’ boundary of exon 10 is identical in both genes while the 3’ non-coding region is 64 bp longer in the human gene. Introns 2,3,6 and 8 have similar sizes in the mouse and human genes; intron 1 is 6-fold smaller, introns 5, 7 and 9 are 2- to 3-fold smaller, whereas intron 4 is about 2-fold larger in the mouse gene. Compared to the human 5’ flanking sequence, an insertion of a simple repeat region with sequence (TGG)n has occurred. The open reading frame of the mouse α2-AP gene encodes a 491-amino acid protein comprising the experimentally determined NH2-terminus of the mature protein Val-Asp-Leu-Pro-Gly-.A targeting vector, ppPNT.α2-AP, was constructed by introducing a homologous sequence of 8.3 kb in total in the parental pPNT vector. In pPNT.α2-AP, the neomycin resistance expression cassette replaces a 7 kb genomic fragment comprising exon 2 through part of exon 10 (including the stop codon), which represents the entire sequence encoding the mature protein, including the fibrin-binding domain, the reactive site peptide bond and the plasmin(ogen)-binding region. Electroporation of 129R1 embryonic stem (ES) cells with the linearized vector pPNT.α2-AP yielded three targeted clones with correct homologous recombination at the 5’- and 3’-ends, as confirmed by Southern blot analysis of purified genomic DNA with appropriate restriction enzymes and probes. These targeted clones will be used to generate α2-AP deficient mice.
Selection of S18326 as a New Potent and Selective Boronic Acid Direct Thrombin Inhibitor
Authors: Rupin A , Mennecier P , Lila C , de Nanteuil G , Verbeuren T J 
Published: July 2018

SummaryUsing enzymatic microassays, the potency of a series of new boroarginine tripeptides was determined versus thrombin and a panel of serine-proteases implicated in the coagulation and fibrinolysis pathways. The inhibition of the serine-protease complement factor I was also studied. Factor I regulates the alternate pathway of the complement and its inhibition appears to be responsible for the toxic effects of the orally available thrombin inhibitor Ac-D-Phe-Pro-boro-Arg (DuP-714). The structure of the new boronic acid derivatives tested was modified from that of DuP-714 by replacing the proline in the P2 position by N-cycloalkyl-glycine residues of increasing size (SI8989: cyclopropyl; S18563: cyclobutyl; S18326: cyclopentyl; S18229: cyclohexyl). All compounds were found to be slow-tight binding inhibitors of thrombin versus purified human fibrinogen. Replacement of proline by N-cycloalkyl-glycines did not decrease the anti-thrombin potency of the substances up to the cyclopentyl size and this result was confirmed by classical coagulation assays with human plasma in vitro. In contrast, the inhibitory activities of the four new boronic acids were found to be lower than those of DuP-714 versus plasmin, urokinase (u-PA), plasmatic kallikrein, activated protein C (aPC) and complement factor I. The cyclopentyl derivative SI8326 is a slightly more active inhibitor of thrombin than DuP-714 (initial IC50 values 3.99 ± 0.18 nM versus 4.73 ± 0.27 nM, respectively). Moreover SI8326 was identified as the most selective compound of the series with relative potencies being 2 to 29 fold higher than that of DuP-714 versus the panel of serine-proteases tested; the rank order of potency versus the other serine-proteases for S18326 was t-PA>kallikrein>aPC> factor I>plasmin>fXa>u-PA. These results indicate that the size of the thrombin hydrophobic pocket S2 is sufficient to accept larger residues than proline in the P2 position of Ac-D-Phe-X-boroArg derivatives while this is not the case for other important serine-proteases of the fibrinolysis, coagulation and complement pathways. The N-cyclopentyl glycine containing derivative SI8326, which is the most potent and the most selective anti-thrombin compound of the series, currently undergoes major preclinical testing.
Standardisation of Protein S in Plasma: Calibration of the 1st International Standard
Authors: Hubbard Anthony R 
Published: July 2018

SummaryAn international collaborative study, involving 16 laboratories, was carried out to calibrate the 1st International Standard Protein S, plasma, for total and free Protein S antigen and for Protein S function. Potency estimates were calculated relative to locally collected fresh normal plasma pools. Estimates of total Protein S antigen showed good agreement between laboratories with inter-laboratory geometric coefficient of variation (gcv%) of 8.8% and a mean value of 0.89 IU/ampoule. Estimates of free Protein S antigen calculated relative to total Protein S antigen in the fresh normal pools were more variable (gcv 26.8%) than estimates calculated relative to free Protein S antigen (gcv 15.3%); the latter comparison was used for calibration with a mean value of 0.89 IU/ampoule. Functional Protein S was estimated using commercial kits which gave an overall mean value of 0.92 IU/ampoule (gcv 14.0%). The 1st International Standard Protein S, plasma, (coded 93/590) was established in October 1995 with a single potency of 0.90 IU/ampoule for all three parameters.
von Willebrand Factor Activity Detected in a Monoclonal Antibody-based ELISA: an Alternative to the Ristocetin Cofactor Platelet Agglutination Assay for Diagnostic Use
Authors: Murdock Paul J , Woodhams Barry J , Matthews Kathy B , Pasi K John , Goodall Alison H 
Published: July 2018

SummaryThe monoclonal antibody RFF-VIII:R/1 recognises an epitope on von Willebrand factor involved in its interaction with GPIbα. A two-site, solid phase ELISA has been established using RFF-VIII:R/1 as the solid-phase, capture antibody and an enzyme-conjugated, polyclonal antibody to human VWF, which provides an assay for VWF functional activity with a detection limit of 0.5 U/dl VWF and an interassay %CV<10. Plasma from 192 VWD patients (48 studied retrospectively; 144 prospectively) showed VWF levels of <50 U/dl in type 1 patients (n = 156), <25 U/dl in type 2A (n = 26) and <35 U/dl in type 2B (n = 8) which, in type 1 and 2A patients, correlated with RiCoF activity (r >0.82). In plasma from patients with type 1 VWD values of VWF in the Mab-based ELISA were similar to levels of VWF:Ag measured in a polyclonal antibody-based ELISA (r >0.87) but were significantly lower than VWF:Ag in type 2A and 2B plasmas (p <0.0005), allowing discrimination of variant VWD. The Mab-based ELISA has advantages of sensitivity and reproducibility over the RiCoF assay to measure VWF activity and can be used to analyse stored samples. In conjunction with an ELISA for VWF:Ag and VWF multimer analysis, it provides a reliable method, for the laboratory diagnosis of VWD.