bluuebunny/crossref_metadata_2025_split huggingface dataset:
α1-Antitrypsin Pittsburgh (Met358 → Arg) Inhibits the Contact Pathway of Intrinsic Coagulation and Alters the Release of Human Neutrophil Elastase during Simulated Extracorporeal Circulation
Authors: Wachtfogel Yanina T , Bischoff Rainer , Bauer Ross , Hack C Erik , Nuijens Jan H , Kucich Umberto , Niewiarowski Stefan , Edmunds L Henry , Colman Robert W 
Published: July 2018

SummaryCardiopulmonary bypass prolongs bleeding time, increases postoperative blood loss, and triggers activation of plasma proteolytic enzyme systems and blood cells referred to as the “whole body inflammatory response”. Contact of blood with synthetic surfaces leads to qualitative and quantitative alterations in platelets, neutrophils, contact and complement systems. Contact and complement pathway proteins both induce neutrophil activation, a j-antitrypsin Pittsburgh (Met358 → Arg), a mutant of α1-antitrypsin, is a potent inhibitor of plasma kalli-krein and thrombin. We investigated whether this recombinant mutant protein inhibited platelet activation, as well as contact and/or complement-induced neutrophil activation during simulated extracorporeal circulation.Arg358 α1-antitrypsin did not prevent the 34% drop in platelet count at 5 min of recirculation, did not block the 50% decrease in ADP-induced platelet aggregation at 120 min of recirculation, nor inhibit the release of 6.06 α 1.07 µg/ml (3-thromboglobulin at 120 min of recirculation suggesting that the inhibitor had little effect on platelet activation. However, Arg358 α1 arantitrypsin totally blocked kallikrein-Cl-in-hibitor complex formation but not Cl-Cl-inhibitor complex formation. Most importantly, Arg358 α1-antitrypsin decreased the release of 1.11 α 0.16 µg/ml human neutrophil elastase by 43%. The attenuation of neutrophil activation in the absence of an effect on complement activation via the classical pathway, supports the concept that kallikrein is a major mediator of neutrophil degranulation during cardiopulmonary bypass.
Studies of the Mechanism for Enhanced Cell Surface Factor VIIa/Tissue Factor Activation of Factor X on Fibroblast Monolayers after Their Exposure to N-Ethylmaleimide
Authors: The Le Dzung , Rapaport Samuel I , Vijaya Mohan Rao L 
Published: July 2018

SummaryFibroblast monolayers constitutively expressing surface membrane tissue factor (TF) were treated with 0.1 mM N-ethylmaleimide (NEM) for 1 min to inhibit aminophospholipid translocase activity without inducing general cell damage. This resulted in increased anionic phospholipid in the outer leaflet of the cell surface membrane as measured by the binding of 125I-annexin V and by the ability of the monolayers to support the generation of prothrombinase. Specific binding of 125I-rVIIa to TF on NEM-treated monolayers was increased 3- to 4-fold over control monolayers after only brief exposure to 125I-rVIIa, but this difference progressively diminished with longer exposure times. A brief exposure of NEM-treated monolayers to rVIIa led to a maximum 3- to 4-fold enhancement of VIIa/TF catalytic activity towards factor X over control monolayers, but, in contrast to the binding studies, this 3- to 4-fold difference persisted despite increasing time of exposure to rVIIa. Adding prothrombin fragment 1 failed to diminish the enhanced VIIa/TF activation of factor X of NEM-treated monolayers. Moreover, adding annexin V, which was shown to abolish the ability of NEM to enhance factor X binding to the fibroblast monolayers, also failed to diminish the enhanced VIIa/TF activation of factor X. These data provide new evidence for a possible mechanism by which availability of anionic phospholipid in the outer layer of the cell membrane limits formation of functional VIIa/TF complexes on cell surfaces.
The 4G/5G Genetic Polymorphism in the Promoter of the Plasminogen Activator Inhibitor-1 (PAI-1) Gene Is Associated with Differences in Plasma PAI-1 Activity but not with Risk of Myocardial Infarction in the ECTIM Study
Authors: Ye S , Green F R , Scarabin P Y , Nicaud V , Bara L , Dawson S J , Humphries S E , Evans A , Luc G , Cambou J P , Arveiler D , Henney A M , Cambien F 
Published: July 2018

SummaryWe have investigated the interrelationships of plasma PAI-1 activity, the PAI-1 4G/5G polymorphism and risk of myocardial infarction (MI) in the ECTIM study, a case-control study of MI based in Belfast, Lille, Strasbourg and Toulouse. Mean PAI-1 levels in cases were similar across all centres but in controls, levels in the French centres were significantly higher. Only in Belfast were PAI-1 levels higher in cases (11.7AU/ml) than controls (10.5AU/ml). The PAI-1 4G allele frequency was similar in cases and controls (0.55 and 0.54). In all groups, 4G homozygotes had the highest mean plasma PAI-1 level (4G4G vs 5G5G; cases overall: 14.2 vs 12.1 AU/ml; controls overall: 15.0 vs 12.6AU/ml), with the heterozygotes generally intermediate. The data from Belfast are consistent with the literature implicating PAI-1 level as an MI risk factor. In ECTIM, the PAI-1 4G/5G polymorphism is not a genetic risk factor for MI but is associated with PAI-1 activity. Thus homozygosity for the 4G allele may predispose to elevated PAI-1 and impaired fibrinolysis, perhaps requiring interaction with other genetic or environmental factors to influence MI risk.
A Collaborative Study of Proposed European Pharmacopoeia Reference Preparations of Low Molecular Mass Heparin
Authors: Gray E , Heath A B , Mulloy B , Spiese J-M , Barrowcliffe T W 
Published: July 2018

SummaryA European collaborative study, in which 16 laboratories participated, was carried out to assess the performance of the European Pharmacopoeia (EP) monograph methods for anticoagulant activities (anti-Xa and anti-IIa assays) of low molecular mass (EMM) heparin and to assess the suitability of six candidate materials as the EP working standard for LMM heparin. There was good interlaboratory agreement for both types of assays as indicated by most gcv’s being less than 10%, indicating acceptable performance of the EP assay methods. All the candidate preparations gave dose-response curves parallel to the 1st International Standard for Low Molecular Weight heparin and to each other. All preparations, possibly with the exception of E and F, gave similar performance as measured by interlaboratory agreement and would be suitable as working standards. Based on these data, preparations A, B, C and D have been established by the EP as official EP Biological Reference Preparations and they will be issued as successive batches.
Hemostasis Abnormalities in Patients with Vascular Dementia and Alzheimer’s Disease
Authors: Mari D , Parnetti L , Coppola R , Bottasso B , Reboldi G P , Senin U , Mannucci P M 
Published: July 2018

SummarySince it has not been established to what extent abnormalities of hemostasis contribute to the occurrence and development of dementia, selected measurements of coagulation and fibrinolysis were obtained in elderly patients with Alzheimer’s disease (n = 22) or vascular dementia (n = 29), compared with healthy individuals in the same age range (n = 61). Hemostasis abnormalities were more frequent and marked in vascular dementia, being expressed as significant increases of plasminogen activator inhibitor type 1, von Willebrand factor, D-dimer. and activated factor VII. However, some hemostasis measurements (von Willebrand factor, activated factor VII) were abnormally high also in the patients with Alzheimer’s disease, a condition in which vascular damage is not considered to play a major pathogenetic role. It could not be established in this study whether or not these hemostatic abnormalities play a causal role in the pathogenesis of dementia, or whether they are secondary to inflammation and chronic vascular disease. Nevertheless, their presence may contribute to aggravating vascular disease.
A Simplified Procedure for Thromboplastin Calibration -The Usefulness of Lyophilized Plasmas Assessed in a Collaborative Study
Authors: Tripodi A , Chantarangkul V , Manotti C , Poggi M , Braga M , Akkawat B , Bucciarelli P , Mannucci P M 
Published: July 2018

SummaryThe International Sensitivity Index (ISI) of thromboplastins is determined by calibration using fresh plasmas from 60 patients stabilized on oral anticoagulants and 20 healthy subjects. This procedure is demanding, particularly for those who have no easy access to patients. The alternative use of a smaller number of lyophilized plasmas has already been considered, but one important issue, the number of repeated measurements to be carried out, has never been addressed. Two commercial rabbit thromboplastins, A and B, were calibrated in 3 laboratories against CRM 149R. On each of 10 working days, prothrombin times were measured for a different set of 8 fresh plasmas and for the same set of 8 lyophilized plasmas. The ISI values for both thromboplastins were estimated by orthogonal regression on fresh and lyophilized plasmas. The between- and within-laboratory CV values of the estimated ISI were taken as measures of precision of the calibration. In addition, ISI and CV were calculated daily on cumulative results obtained with lyophilized plasmas from day 1 to day 10. The ISI values for both thromboplastins calculated with lyophilized plasmas were not significantly different from those with fresh plasmas (mean of 3 laboratories: 1.42 vs 1.48 for A and 1.22 vs 1.20 for B). The between-laboratory precision of the calibration with lyophilized plasmas was not considerably different from that with fresh plasmas (CV for 3 labs: 5.2% vs 6.8% for A and 0.9% vs 2.2% for B). The ISI estimated with lyophilized plasmas on results of day 1 were not different from those of days 2 through 10. Good within-laboratory precision of the calibration (CV around 2%) was already achieved on day 3. In conclusion, this study shows that lyophilized plasmas pooled from normals and patients on oral anticoagulants can be used as substitutes for individual fresh plasmas to simplify the existing procedure for thromboplastin calibration.
Characterization of Recombinant Human Coagulation Factor XFriuli
Authors: Kim D J , Girolami A , James H L 
Published: July 2018

SummaryNaturally occurring plasma factor XFriuli (pFXFr) is marginally activated by both the extrinsic and intrinsic coagulation pathways and has impaired catalytic potential. These studies were initiated to obtain confirmation that this molecule is multi-functionally defective due to the substitution of Ser for Pro at position 343 in the catalytic domain. By the Nelson-Long site-directed mutagenesis procedure a construct of cDNA in pRc/CMV was derived for recombinant factor XFriuli (rFXFr) produced in human embryonic (293) kidney cells. The rFXFr was purified and shown to have a molecular size identical to that of normal plasma factor X (pFX) by gel electrophoretic, and amino-terminal sequencing revealed normal processing cleavages. Using recombinant normal plasma factor X (rFXN) as a reference, the post-translational y-carboxy-glutamic acid (Gla) and (β-hydroxy aspartic acid (β-OH-Asp) content of rFXFr was over 85% and close to 100%, respectively, of expected levels. The specific activities of rFXFr in activation and catalytic assays were the same as those of pFXFr. Molecular modeling suggested the involvement of a new H-bond between the side-chains of Ser-343 and Thr-318 as they occur in anti-parallel (3-pleated sheets near the substrate-binding pocket of pFXFr. These results support the conclusion that the observed mutation in pFXFr is responsible for its dysfunctional activation and catalytic potentials, and that it accounts for the moderate bleeding tendency in the homozygous individuals who possess this variant procoagulant.
Aggregated, Conformationally Changed Fibrinogen Exposes the Stimulating Sites for t-PA-Catalysed Plasminogen Activation
Authors: Haddeland Unni , Sletten Knut , Bennick Anne , Nieuwenhuizen Willem , Brosstad Frank 
Published: July 2018

SummaryThe present paper shows that conformationally changed fibrinogen can expose the sites Aα-(148-160) and γ-(312-324) involved in stimulation of the tissue-type plasminogen activator (t-PA)-catalysed plasminogen activation. The exposure of the stimulating sites was determined by ELISA using mABs directed to these sites, and was shown to coincide with stimulation of t-PA-catalysed plasminogen activation as assessed in an assay using a chromogenic substrate for plasmin. Gel permeation chromatography of fibrinogen conformationally changed by heat (46.5° C for 25 min) demonstrated the presence of both aggregated and monomeric fibrinogen. The aggregated fibrinogen, but not the monomeric fibrinogen, had exposed the epitopes Aα-(148-160) and γ-(312-324) involved in t-PA-stimulation. Fibrinogen subjected to heat in the presence of 3 mM of the tetrapeptide GPRP neither aggregates nor exposes the rate-enhancing sites. Thus, aggregation and exposure of t-PA-stimulating sites in fibrinogen seem to be related phenomena, and it is tempting to believe that the exposure of stimulating sites is a consequence of the conformational changes that occur during aggregation, or self-association. Fibrin monomers kept in a monomeric state by a final GPRP concentration of 3 mM do not expose the epitopes Aα-(148-160) and γ-(312-324) involved in t-PA-stimulation, whereas dilution of GPRP to a concentration that is no longer anti-polymerizing, results in exposure of these sites. Consequently, the exposure of t-PA-stimulating sites in fibrin as well is due to the conformational changes that occur during selfassociation.
Factor VII Gene Polymorphisms, Factor VII:C Levels and Features of Insulin Resistance in Non-Insulin-Dependent Diabetes mellitus
Authors: Heywood Daniella M , Mansfield Michael W , Grant Peter J 
Published: July 2018

SummaryThe macrovascular complications of non-insulin-dependent diabetes mellitus (NIDDM) are related to the features of insulin resistance (IR). High Factor VII :C (FVII:C) levels are associated with increased cardiovascular risk and relate to a base change in the FVII gene detected by Msp I endonuclease, and also to an insertion polymorphism in the promoter region. To examine the association between FVII:C levels, genotype and features of IR, 95 NIDDM patients were studied. Genotype was related to FVII:C levels (M1M1 137%, n = 75; M1M2 and M2M2 114%, n = 20, p <0.005; AA 136%, n = 71; Aa 119%, n = 21, p <0.05), which is consistent with previous studies in healthy populations. FVII: C correlated with cholesterol (r = 0.51, p <0.0005), insulin (r = 0.36, p = 0.002), triglycerides (r = 0.34, p = 0.001), age (r = 0.23, p <0.005) and body mass index (r = 0.23, p <0.05). When analysed by Msp I genotype, the stronger predictor of FVII: C levels, these correlations remained, with no difference in regression slopes. In a multiple regression model, genotype, cholesterol, insulin, and gender remained as independent predictors of FVII:C levels. In conclusion, FVII :C concentrations are elevated in NIDDM in relation to both FVII genotypes and features of IR.
Isolation and Characterization of Canine Factor IX
Authors: Sugahara Yuichi , Catalfamo James , Brooks Marjory , Hitomi Eri , Bajaj S Paul , Kurachi Kotoku 
Published: July 2018

SummaryCanine plasma factor IX was purified to homogeneity by a combination of barium citrate precipitation and three-step column chromatographies of DEAE sepharose, heparin agarose and a monoclonal antifactor IX antibody-linked agarose. Canine factor IX has an apparent molecular size of 61 kDa, which is slightly smaller than that of human factor IX, as determined by denatured polyacrylamide gel electrophoresis. Its amino acid composition, amino-terminal and carboxyterminal amino acid sequences agreed well with those predicted from the reported cDNA. Unlike purified human factor IX, canine factor IX preparation often showed a discrete smaller molecular species (∼50 kDa) which was generated by a specific proteolytic cleavage between Arg310 and Val311. When purified canine factor IX was utilized as a standard for enzyme linked immunosorbent assay, the concentration of canine factor IX in the pooled normal dog plasma was determined to be 5.3 Μg/ml with 11.2% carbohydrate content (or 4.7 Μg/ml for its polypeptide chain moiety). Concentration of plasma factor IX antigen was measured in six severely affected, unrelated hemophilia B dogs. Four had factor IX antigen of less than 1% of the normal, and two had undetectable levels. The latter two had gross molecular abnormalities in their factor IX genes. Three obligate carrier females had variable but proportionately reduced factor IX antigen and factor IX coagulant activity levels. These results provide a quantitative method for measuring canine factor IX antigen which is a prerequisite for studying hemostasis and development of gene transfer approaches in the canine model of hemophilia B.
Technical and Biological Conditions Influencing the Functional APC Resitance Test
Authors: Freyburger G , Bilhou-Nabera C , Dief S , Javorschi S , Labrouche S , Lerebeller M J , Boisseau M R 
Published: July 2018

SummaryPoor anticoagulant response to APC is conveniently screened by a commercially available functional test (Coatest® APC Resistance) allowing identification of APC-resistant patients. These patients may then be genotyped with respect to factor V, the Arg - > Gin mutation being the principle cause of APC resistance. However, determination of phenotype generally precedes that of genotype, and the need for an “abnormality threshold” prompted a study of inter-batch variations and the clinical conditions associated with an altered APC response. The response to APC was assessed twice in plasma from 111 patients using two of four successive kit batches. A modest but significant inter-batch variability was observed. At the same time, we also tested 130 patients with retinal venous occlusion (RVO), 28 patients with glaucoma and 24 normal volunteers. The APCaPTT/aPTT ratio was found to be lower in the presence of elevated thrombin-antithrombin complexes (r = 0.167, p <0.02) and low blood viscosity (at high shear rate: r = 0.305, p <0.0001) independently of any alteration in genotype.
Comparison between Recombinant and Rabbit Thromboplastin in the Management of Patients on Oral Anticoagulant Therapy
Authors: Barcellona D , Biondi G , Vannini M L , Marongiu F 
Published: July 2018

SummaryThe aim of this study was to compare recombinant thromboplastin (rTF, ISI = 0.82) with rabbit thromboplastin (RT, ISI = 1.46) in order to evaluate which performed better in our thrombosis centre. To this purpose we randomized 67 patients to be double-blind monitored in two groups for three months either with PT performed with RT or with PT performed with rTF. After this period each patient was shifted to the other group. We considered the following as end points of the study: percentages of PT results within the therapeutic range, number of visits and therapeutic dose adjustments per patient. The “last check in file” method was used to evaluate the laboratory quality of oral anticoagulation for both thromboplastins. The results show that there was no difference in the number of visits per patient between the two groups: 6.9 ± 1.7 in the rTF group versus 7.3 ± 1.9 in the RT group (p = 0.19). The variations of therapeutic dose per patient were not different in the two groups: the dose was changed once (range 0-8) in the rTF group and once (range 0-11) in the RT group (p = 0.15). The percentages of PT results within the therapeutic range were not different between the two groups. The “last check in file” method showed similar percentages in both groups: PT results in the therapeutic range were 67.2% in the RT group and 68.8% in the rTF group. We conclude that the two thromboplastins had a similar effect on the end points of the study in spite of the relatively high ISI of the RT.
Physico-Chemical Properties and the Structure of Dermatan Sulfate Fractions Purified from Plasma after Oral Administration in Healthy Human Volunteers
Authors: Volpi Nicola 
Published: July 2018

SummaryDermatan sulfate (DS) was administered by oral route in healthy human volunteers. The structure, physico-chemical properties and biological activity of DS purified from human plasma after oral administration were studied and compared with those of native DS.DS extracted and purified from pig mucosa has a relative molecular mass (Mr) of about 23,100 and is composed of about 10% nonsulfated disaccharide, 80% monosulfated disaccharides and about 10% disulfat-ed disaccharides, with a sulfate to carboxyl ratio of 1.00 and a heparin cofactor II (HCII) activity of about 160 units/mg. This native polysaccharide is composed of about 94% iduronic acid.One gram of native DS was orally administered to five healthy human volunteers, and 50 ml of blood were collected after 4 h. DS possibly present in plasma after oral administration was extracted and purified. About 130 ± 42 Μg of DS per 50 ml of blood were detected by agarose-gel electrophoresis and DMB assay. This DS shows a broad Mr range. After oral absorption, substantial amounts of species with a Mr of about 7,500 are detected in blood but chains with Mr ranging from 7,500 to 20,000 are also found. Moreover, some very low-Mr species are detected, with a prevalence of disaccharides. After oral absorption, DS is sulfated above all in position 4 of the N-acetyl-galactosamine (60%), with a sulfate to carboxyl ratio of about 0.64, demonstrating that DS is desulfated during or after oral absorption by about 30-40%. A small amount of disulfated disaccharide (in particular 2,4-disulfated, 1.4%) is preserved from catabolic processes, as DS extracted from human plasma is able to inhibit thrombin activity mediated by HCII (about 16 U/mg).
Effect of Lipoprotein(a) and LDL on Plasminogen Binding to Extracellular Matrix and on Matrix-dependent Plasminogen Activation by Tissue Plasminogen Activator
Authors: Pekelharing Hadewijch L M , Kleinveld Henne A , Duif Pieter F C.C.M , Bouma Bonno N , van Rijn Herman J M 
Published: July 2018

SummaryLp(a) is an LDL-like lipoprotein plus an additional apolipoprotein apo(a). Based on the structural homology of apo(a) with plasminogen, it is hypothesized that Lp(a) interferes with fibrinolysis. Extracellular matrix (ECM) produced by human umbilical vein endothelial cells was used to study the effect of Lp(a) and LDL on plasminogen binding and activation. Both lipoproteins were isolated from the same plasma in a single step. Plasminogen bound to ECM via its lysine binding sites. Lp(a) as well as LDL were capable of competing with plasminogen binding. The degree of inhibition was dependent on the lipoprotein donor as well as the ECM donor. When Lp(a) and LDL obtained from one donor were compared, Lp(a) was always a much more potent competitor. The effect of both lipoproteins on plasminogen binding was reflected in their effect on plasminogen activation. It is speculated that Lp(a) interacts with ECM via its LDL-like lipoprotein moiety as well as via its apo(a) moiety.