bluuebunny/crossref_metadata_2025_split huggingface dataset:
In Vitro Characterisation of Two Naturally Occurring Mutations in the Thrombin-sensitive Region of Anticoagulant Protein S
Authors: Giri Tusar , de Frutos Pablo García , Yamazaki Tomio , Villoutreix Bruno , Dahlbäck Björn 
Published: March 2018

SummaryThe molecular consequences of two naturally occurring mutations in the thrombin-sensitive region of protein S were investigated using a combination of recombinant protein expression, functional analysis and molecular modelling. Both mutations (R49H and R70S) have been found in thrombosis patients diagnosed as having type I protein S deficiency. Molecular modelling analysis suggested the R49H substitution not to disrupt the structure of thrombin-sensitive region, whereas the R70S substitution could affect the 3D structure mildly. To elucidate the molecular consequences of these substitutions experimentally, site directed mutagenesis of protein S cDNA and expression in mammalian cells created the two mutants. The secretion profiles and functional anticoagulant activities of the protein S mutants were characterised. Secretion of the R49H mutant was similar to that of wild type protein S, whereas the R70S mutant showed moderately decreased expression. Neither of the mutants showed any major functional defects as cofactors to activated protein C (APC) in an APTT-based assay or in degradation of factor Va. However, both mutants demonstrated decreased activity in a factor VIIIa degradation assay, which in addition to APC and protein S also included factor V as synergistic APC cofactor. In conclusion, the R49H substitution did not produce a quantitative abnormality in vitro, raising doubts as to whether it caused the type I deficiency. In contrast, the experimental data obtained for the R70S mutant agrees well with the observed type I deficiency. Our study illustrates that in vitro experimental characterisation together with computer-based structural analysis are useful tools in the analysis of the relationship between naturally occurring mutations and clinical phenotypes.
Poor Relationship between Phenotypes of Protein S Deficiency and Mutations in the Protein S Alpha Gene
Authors: Hermida José , Mannucci Pier Mannuccio , Faioni Elena 
Published: March 2018

SummaryBy single strand conformational polymorphism, nucleotide sequencing and enzyme restriction, we analyzed the protein S α gene in 17 protein S-deficient probands and in their available family members. The relationship between genotype and phenotype was also evaluated. Twelve different sequence variations were identified in 17 probands. Ten were putative causal mutations distributed in 16 probands: 4 were nonsense, 5 missense and one a splice site mutation. In most families in which a mutation was identified, more than one phenotype of PS deficiency was present. The same splice site mutation (intron j G-A, exon 10+5) was associated with type I deficiency in one family and with type I/III in another unrelated family. A phenotypic discrepancy was also observed for the Arg474Pro, Gly597Asp and Arg410stop mutations. Glu26Ala, previously reported in kindreds with type I deficiencies, was found in association with I, II and III phenotypes in four unrelated kindreds. Phenotypic analysis of protein S deficiency is poorly related to the underlying genetic defect.
Pharmacokinetics of Recombinant Factor VIII (Recombinate) Using One-stage Clotting and Chromogenic Factor VIII Assay
Authors: Owens D. , Bray G. , Giangrande P. , Collins P. , Hay C. , Gomperts E. , Schroth P. , Barrowcliffe T. , Lee C. A. 
Published: March 2018

SummaryIn a study designed to demonstrate the safety and pharmacokinetics of a recombinant factor VIII (Recombinate) manufactured in Andover, MA and Thousand Oaks, CA, two different methods of factor VIII assay (one-stage clotting and Chromogenic substrate) were compared in vivo. The study was performed in four centres in the UK: London, Oxford, Cardiff and Manchester. Two pharmacokinetic studies, at least one week apart, were performed in 30 patients with severe haemophilia A (VIII:C < 2 IU/dl). A dose of 50 IU/kg was administered with sampling pre-infusion, and +0.25, 0.5, 1, 3, 6, 9, 12 and 24 h post-infusion. The aggregate 60 pharmacokinetic study showed a half-life of 12.7 and 13.0 h (p = 0.28) and recovery of 127 and 161 IU/dl (p = 0.0001) using one-stage clotting or chromogenic substrate respectively. In a supplementary experiment, 20 post-infusion samples were re-assayed by 1-stage and chromogenic assay using two plasma (20th British plasma standard and an “in-house” pooled normal plasma) and two concentrate standards, derived from the same type, but different batch of infused concentrate (Recombinate) and pre-diluted in either individual pre-infusion sample or in pooled commercial haemophilic plasma. The use of the Recombinate concentrate standard overcame the significant difference in FVIII levels between 1-stage and chromogenic assay methods when a plasma standard was used (p <0.0001). It is concluded that where potency dosing designation is carried out by an assay system different to that used in the clinical situation, the use of the recombinant concentrate as a standard in post-infusion plasma samples is likely to give more reliable and reproducible results.
Mutations in the αIIb and β3 Genes that Cause Glanzmann Thrombasthenia Can Be Distinguished by a Simple Procedure Using Transformed B-Lymphocytes
Authors: Rosenberg Nurit , Dardik Rima , Rosenthal Ester , Zivelin Ariella , Seligsohn Uri 
Published: March 2018

SummaryGlanzmann thrombasthenia (GT) is caused by a defect in either glycoprotein (GP) IIb (αIIb) or GPIIIa (β3) genes and therefore screening of both genes is required for mutation identification. The β subunit of the GPIIb/IIIa complex (β3) forms a complex with another α subunit (αv) yielding the αvβ3 vitronectin receptor (VnR). GT patients with mutations in the GPIIIa gene that cause diminished synthesis of GPIIIa are deficient in both GPIIb\IIIa and VnR, whereas patients with mutations in the GPIIb gene are deficient in GPIIb\IIIa, yet express normal or increased VnR in their platelets. The presence or absence of VnR in platelet membranes of GT patients has therefore been used for distinguishing between mutations in the GPIIb gene and mutations in the GPIIIa gene. However, the method of assessing VnR in platelets is cumbersome and use of fresh platelets is indispensible. In the present work we devised a procedure for detection of the VnR in B-lymphocytes transformed by Epstein-Bar virus (EBV). The transformed lymphocytes transcribed GPIIIa mRNA but not GPIIb mRNA and expressed VnR on their surface. Using flow cytometry analysis or immuno-precipitation and western blotting VnR was found in B-lymphocytes of GT patients bearing a well characterized mutation in the GPIIb gene. In contrast, in B-lymphocytes of GT patients bearing 2 different mutations in the GPIIIa gene no VnR was detectable. Thus, for determining which gene is mutated in a GT patient, EBV-transformed B-lymphocytes are useful and can as well be used for analyses of GPIIIa mRNA and genomic DNA. Ten ml of blood are sufficient for the procedure.
IgA Anticardiolipin Antibodies – Relation with other Antiphospholipid Antibodies and Clinical Significance
Authors: Ordi-Ros Josep , Monegal-Ferran Francesc , Martinez Nuria , Cortes-Hernandez Fina , Vilardell-Tarres Miquel , Selva-O’Callaghan Albert 
Published: March 2018

SummaryObjective: To evaluate the usefulness of IgA antiphospholipid antibodies as markers of thrombosis and/or antiphospholipid antibody syndrome. Patients and Methods: A cross-sectional study design in a tertiary, university-based, autoimmune reference hospital. Seven-hundred ninety-five patients classified into five different groups – autoimmune diseases (255), deep vein thrombosis (153), transitory ischemic attacks (108), obstetric complications (196), infectious diseases (83) and controls (81) – were tested for IgA, IgG and IgM aPL, and lupus anticoagulant. Plasma and serum samples were drawn for detection of aPL using an internationally standardized ELISA method and LA was carried out using coagulometric assays. Results: True IgA aPL were found only in two patients with systemic lupus erythematosus; these patients were also positive to IgG aPL. Conclusion: The incidence of true positivity to IgA anticardiolipin antibodies is extremely low. Their determination was not helpful in diagnosing the antiphospholipid syndrome or in explaining thrombotic events or aPL related manifestations – fetal loss – in the groups studied.
Patterns of Hepatitis G Viraemia and Liver Disease in Haemophiliacs Previously Exposed to Non-virus Inactivated Coagulation Factor Concentrates
Authors: Jarvis Lisa , Hayes Peter , Lee Amanda , Simmonds Peter , Ludlam Christopher , Hanley John 
Published: March 2018

SummaryHepatitis G virus (HGV), a novel flavivirus, has been implicated as a cause of posttransfusion hepatitis. We have performed a longitudinal study in a cohort of haemophiliacs (n = 68) who previously received non-virus inactivated coagulation factor concentrates to assess both patterns of HGV viraemia and any associated liver disease. Hepatitis C virus (HCV) RNA was present in 58/68 and co-infection with human immunodeficiency virus (HIV) was present in 15/68.HGV RNA was detected in 17/68 (25%) samples from the mid-1980s. There was no association between either HIV infection (p = 0.74) or co-infection with a particular HCV genotype (p = 0.62). However, there was a relationship between HGV viraemia and the severity of haemophilia (p = 0.0004) with HGV RNA detected in 5/19, 9/16 and 3/32 patients with mild, moderate and severe haemophilia respectively.A longitudinal study was performed in 15/17 haemophiliacs with HGV viraemia using stored serum samples from the 1980s and 1990s. HGV viraemia persisted in 8/15 and cleared in 7/15 over a variable period of time. A Weibull model was constructed to estimate the duration of HGV viraemia in the study group. The 75th and 90th percentiles for the duration of HGV were estimated to be 8.7 years (95%, confidence interval 4.8-15.7) and 23.6 years (95% confidence interval 11.8-47.1) respectively. Laparoscopic liver inspection/biopsy was performed in 25/68. There was no association between severity of liver disease and HGV viraemia (p = 0.43). This study demonstrates considerable variation in patterns of HGV viraemia in haemophiliacs. We found little evidence to implicate HGV as a major cause of chronic liver disease in haemophiliacs.
Cloning, Expression, and Characterization of Mouse Tissue Factor Pathway Inhibitor (TFPI)
Authors: Monroe Dougald , Oliver Julie , Liles Darla , Roberts Harold , Chang Jen-Yea 
Published: March 2018

SummaryTissue factor pathway inhibitor (TFPI) acts to regulate the initiation of coagulation by first inhibiting factor Xa. The complex of factor Xa/ TFPI then inhibits the factor VIIa/tissue factor complex. The cDNA sequences of TFPI from several different species have been previously reported. A high level of similarity is present among TFPIs at the molecular level (DNA and protein sequences) as well as in biochemical function (inhibition of factor Xa, VIIa/tissue factor). In this report, we used a PCR-based screening method to clone cDNA for full length TFPI from a mouse macrophage cDNA library. Both cDNA and predicted protein sequences show significant homology to the other reported TFPI sequences, especially to that of rat. Mouse TFPI has a signal peptide of 28 amino acid residues followed by the mature protein (in which the signal peptide is removed) which has 278 amino acid residues. Mouse TFPI, like that of other species, consists of three tandem Kunitz type domains. Recombinant mouse TFPI was expressed in the human kidney cell line 293 and purified for functional assays. When using human clotting factors to investigate the inhibition spectrum of mouse TFPI, it was shown that, in addition to human factor Xa, mouse TFPI inhibits human factors VIIa, IXa, as well as factor XIa. Cloning and expression of the mouse TFPI gene will offer useful information and material for coagulation studies performed in a mouse model system.
Modulation of Pro- and Antifibrinolytic Properties of Human Peritoneal Mesothelial Cells by Transforming Growth Factor β1 (TGF- β1), Tumor Necrosis Factor α (TNF-α) and Interleukin β1 (IL-1β)
Authors: Elbrecht Anne , Schauerte Carsten , Klosterhalfen Bernd , Amo-Takyi Baffour , Gehlen Johanna , Winkeltau Gerd , Mittermayer Christian , Handt Stefan , Tietze Lothar 
Published: March 2018

SummaryA decreased fibrinolytic activity of serosal surfaces appears to be a major factor in the development of peritoneal fibrous adhesions. Serosal fibrinolysis is regulated by mesothelial release of tissue type plasminogen activator (t-PA) and plasminogen activator inhibitor types 1 and 2 (PAI-1 and PAI-2). We investigated the influence of tumor necrosis factor alpha (TNF-α), transforming growth factor β (TGF- β1) and interleukin 1β (IL-1β) on pro- and antifibrinolytic properties of mesothelial cells (HOMC) using a cell/fibrin clot assay. TGF-β1, TNF-α and IL-1β induced a dose dependent 2.9, 2.3 and 1.9-fold increase of PAI-1 antigen, respectively, whereas t-PA concentrations decreased to one third of the control values. This modified PAI-1/t-PA secretion pattern leads to a significant delay of fibrinolysis. Analysis of m-RNA levels revealed increased PAI-1 m-RNA concentrations after 12 h and decreased m-RNA concentrations for t-PA after 6 h. Serosal hypofibrinolysis during peritonitis may be explained at least in part by cytokine effects which thus may favor adhesion formation.
Effect of Antihypertensive Treatment with Doxazosin on Insulin Sensitivity and Fibrinolytic Parameters
Authors: Christ Günter , Gabriel Harald , Mundigler Gerald , Beckmann Renate , Binder Bernd , Huber Kurt , Zehetgruber Manfred 
Published: March 2018

SummaryThe effects of the selective alpha-1-adrenoceptor antagonist doxazosin on metabolic and fibrinolytic parameters were studied in hypertensive patients with various degrees of fasting plasma insulin levels (Group A: 22.5 ± 3 μU/ml, Group B: 8.1 ± 1.5 μU/ml; p <0.01) to disclose a potential link between a doxazosin-induced alteration of insulin and/or lipid metabolism and possible changes of these parameters on the fibrinolytic system. Doxazosin treatment resulted in a dose-dependent reduction of basal insulin levels in group A to 16 ± 3 μU/ml; p <0.05. This finding was paralleled by a dose-dependent increase in t-PAmass concentration in the same patient group (basal t-PAmass from 9.7 ± 1 to 15.5 ± 2 ng/ml; p <0.05). As PAI-1 “active” as well as total antigen levels were not altered in parallel, the net effect on the endogenous fibrinolytic system is an increase of the fibrinolytic potential.
In Vitro Anticoagulant Properties of a Minimum Functional Fragment of Human Thrombomodulin and In Vivo Demonstration of its Benefit as an Anticoagulant in Extracorporeal Circulation Using a Monkey Model
Authors: Suzuki Makoto , Yamamoto Syuji , Mohri Mitsunobu 
Published: March 2018

SummaryRecently, we demonstrated that the last three consecutive epidermal growth factor-like structures of human thrombomodulin form the minimum functional fragment for protein C activating activity. In this study, the recombinant minimum functional fragment of human thrombomodulin (E456) had similar activities for protein C activation and clotting time compared to the recombinant extracellular domains of human thrombomodulin (rhsTM) previously described. E456 had a shorter half-life (6-9 min) in animals, compared to rhsTM (5 h). To evaluate whether or not E456 is a suitable anticoagulant for extra-corporeal circulation, the effects of E456 were investigated in the extracorporeal circulation model in monkeys. The effect of E456 at a dose of 0.03 mg/kg plus 0.113 mg/kg/h on circuit pressure was as potent as that of low molecular weight heparin, Fragmin, at a dose of 30 IU/kg plus 15IU/kg/h. E456, however, also more effectively suppressed an increase of thrombin-antithrombin III complex than Fragmin. Also the APTT quickly returned to the pre-treatment level following E456, but did not when using Fragmin. Moreover, E456 had no influence on the plasma free fatty acid levels, while Fragmin significantly increased them. Thus, E456 appears to have anticoagulant properties which make it more suitable anticoagulant in extracorporeal circulation than Fragmin.
BCH-2763, a Novel Potent Parenteral Thrombin Inhibitor, Is an Effective Antithrombotic Agent in Rodent Models of Arterial and Venous Thrombosis – Comparisons with Heparin, r-Hirudin, Hirulog, Inogatran and Argatroban
Authors: Finkle Carolyn , Pierre Annie , Leblond Lorraine , Deschenes Isabelle , DiMaio John , Winocour Peter 
Published: March 2018

SummaryCurrent clinical use of heparin as an antithrombotic agent is limited by suboptimal efficacy and safety considerations. Thrombin’s central role in thrombosis makes it an attractive target to develop more effective and safer antithrombotic agents. BCH-2763 is a novel, potent (Ki: 0.11 nM), low molecular weight (1.51 kDa), bivalent direct thrombin inhibitor. The antithrombotic efficacy of BCH-2763 in vivo following i.v. bolus plus infusion in rats was compared in arterial and venous thrombosis models with two other bivalent direct thrombin inhibitors, r-hirudin and hirulog, with two catalytic site-directed thrombin inhibitors, inogatran and argatroban, and with heparin. In vivo efficacy was related to inhibition in vitro of fibrin clot formation, thrombin-induced aggregation of rat or human washed platelets and activity of free and plasma clot-bound thrombin. All the direct thrombin inhibitors were effective on both arterial and venous thrombosis at markedly lower fold aPTT increases than heparin. The antithrombotic doses of all inhibitors against venous thrombosis were less than against arterial thrombosis. The rank order of potency based on doses (mg/kg/h) required for full efficacy against arterial thrombosis was BCH-2763 (1.2) inogatran (1.5) r-hirudin (1.8) hirulog (3.3) argatroban ( 3.0); heparin required a markedly higher dose (5.7). In venous thrombosis the doses required for full efficacy were substantially lower for the bivalent (BCH-2763: 0.12; r-hirudin: 0.12; hirulog: 0.18) than for the catalytic site-directed (inogatran: 0.48; argatroban: 0.90) thrombin inhibitors; the dose required for heparin was 0.19. All the direct thrombin inhibitors caused similar shifts in aPTT at doses required to inhibit arterial thrombosis, but BCH-2763 inhibited venous thrombosis at lower aPTT fold increases. In vivo antithrombotic efficacy of direct thrombin inhibitors correlated with their inhibitory activity in vitro against fibrin clot formation and platelet aggregation. In contrast to heparin, all the direct thrombin inhibitors inhibited plasma clot-bound thrombin, but the relative IC50s did not correlate with their antithrombotic efficacy. In summary, direct thrombin inhibitors are more effective than heparin in inhibiting arterial and venous thrombosis in rats with less aPTT increases. BCH-2763 is effective at lower doses than the other direct thrombin inhibitors and for venous thrombosis at a smaller aPTT increase. BCH-2763 may offer an improved therapeutic index in the treatment of thromboembolic complications over heparin and other direct thrombin inhibitors.
Comparative Studies of an Orally-active Factor Xa Inhibitor, YM-60828, with other Antithrombotic Agents in a Rat Model of Arterial Thrombosis
Authors: Sato Kazuo , Sakai Yumiko , Hirayama Fukushi , Koshio Hiroyuki , Taniuchi Yuta , Matsumoto Yuzo , Kawasaki Tomihisa 
Published: March 2018

SummaryWe examined the antithrombotic activity of a novel synthetic inhibitor of factor Xa, YM-60828, in an electrically-induced carotid artery thrombosis model in rats. In the first experiment, the antithrombotic activity of YM-60828 after i.v. infusion was compared with those of heparin, darteparin and argatroban. Test drug was administered by i.v. infusion from 30 min before electrical stimulation to the end of the experiment. YM-60828 at 1 mg/kg/h significantly improved patency status, prolonged the time to occlusive thrombus formation and duration of patency. Heparin at 300 U/kg/h also improved these parameters, but were accompanied by a marked increase in systemic coagulation time. In the second experiment, the antithrombotic activity of YM-60828 after oral administration was compared with those of ticlopidine, cilostazol, aspirin, beraprost, ethyl icosapentate and warfarin. Test drug was orally administered to fasted rats 60 min before electrical stimulation. YM-60828 at 30 mg/kg p.o., but not ticlopidine, cilostazol, aspirin, beraprost, ethyl icosapentate or warfarin, significantly reduced the incidence of occlusion and improved carotid arterial patency. These results suggest that YM-60828 may be a promising antithrombotic agent for the treatment and prevention of arterial thrombosis which can be given by oral as well as intravenous administration.
Predictive Value of Plasma Thrombomodulin in Preeclampsia and Gestational Hypertension
Authors: Valsecchi Luca , Fausto Alfonso , Gozin Danielle , Vigano’ D’Angelo Silvana , Safa Omid , Castiglioni Maria Teresa , Amiral Jean , D’Angelo Armando , Boffa Marie-Claire 
Published: March 2018

SummaryIn a prospective longitudinal study, 130 primigravidae at risk for preeclampsia were examined and plasma sampling performed in 45 of them. Plasma thrombomodulin (pTM) was sequentially measured at weeks 12, 24 and 32 of gestation and after delivery in 20 primigravidae who developed either mild preeclampsia (n = 8) or gestational hyper-tension (n = 12) between weeks 32 and 39 of gestation and in 25 (age-matched) primigravidae who had uneventful pregnancies. pTM elevations were not observed until week 32 in uneventful pregnancies, but were present by week 24 (p = 0.002) in patients who later developed hypertensive complications. A net individual pTM increase ≥4.2 ng/ml between weeks 12 and 24 (more than 8 times that of normotensive primigravidae) and/or pTM level ≥47.5 ng/ml at week 32 predicted the development of hypertensive complications with 80% accuracy. Serial pTM determinations can be useful to select pregnancies who may benefit from early pharmacological intervention.
Elevation of Serum Thrombopoietin Precedes Thrombocytosis in Kawasaki Disease
Authors: Ishikita Takashi , Shimbo Toshikazu , Matsubara Kousaku , Baba Kunizou , Hayashi Yasuhide , Naritaka Shin-ichi , Nakahata Tatsutoshi , Ishiguro Akira 
Published: March 2018

SummaryKawasaki disease (KD) is an acute systemic vasculitis causing coronary arterial aneurysms and myocardial infarction in young children. Prominent thrombocytosis with increased megakaryocytes develops during the convalescent period. To clarify the mechanisms of thrombocytosis, we studied serum levels of thrombopoietin (TPO) and other thrombopoietic cytokines in 40 patients with KD (149 samples) and 106 age-matched controls using ELISA. TPO values in the controls were 1.94 ± 0.69 fmol/ml (mean ± SD) with a 95% reference interval of 0.85 to 3.27 fmol/ml. In the first week of KD, platelet counts were normal but TPO values increased (~ 15.5 fmol/ml). TPO levels peaked on day 6 ± 2 at 5.94 ± 2.64 fmol/ml and then fell gradually. When platelet counts peaked in the second to third weeks, TPO levels were still high or comparable with the controls. TPO levels in KD patients with normal platelet counts were significantly higher than control levels. Interleukin (IL)-6 levels in the first week rose, but neither IL-11 nor leukemia inhibitory factor was detectable. These results suggest that TPO contributes to thrombocytosis in KD in conjunction with IL-6 and TPO production may be enhanced during the acute phase.