bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lupus Anticoagulant is the Strongest Risk Factor for both Venous and Arterial Thrombosis in Patients with Systemic Lupus Erythematosus
Authors: Horbach Daniëlle A , Oort Erica V , Donders Richard C J M , Derksen Ronald H W M , de Groot Philip G 
Published: July 2018

SummaryAntiphospholipid antibodies (aPL) characterize patients at risk for both arterial and venous thrombotic complications. Recently it has been recognized that the presence of plasma proteins such as β2-glycoprotein I (β2GPI) and prothrombin are essential for the binding of aPL to phospholipids and that these proteins are probably the real target of aPL. The discovery of these new antigens for aPL introduces the possibility of new assays to detect the presence of aPL. However, it is not known whether these assays improve the identification of patients at risk for thrombosis.In this retrospective study we compared the value of the classic assays LAC (lupus anticoagulant) and ACA (anticardiolipin antibodies) to detect aPL associated with thrombotic complications, with new assays which are based on the binding of aPL to the plasma proteins prothrombin and P2GPI. To do so, we have used these assays in a group of 175 SLE patients and correlated the positivity of the different assays with the presence of a history of venous and arterial thrombosis. Control groups were patients without SLE but with LAC and/or ACA and thrombosis (n = 23), patients with thrombosis without LAC and ACA (n = 40) and 42 healthy controls.In the univariate analysis, in which no distinction has been made between high and low antibody levels, we confirmed LAC and ACA to be related to both arterial and venous thrombosis. Anti-β2GPI- and anti-prothrombin-antibodies, both IgG and IgM correlate with venous thrombosis and anti-β2GPI-IgM with arterial thrombosis. Multivariate analysis showed that LAC is the strongest risk factor (OR 9.77; 95% CI 1.74-31.15) for arterial thrombosis. None of the other factors is a significant additional risk factor. For venous thrombosis LAC is the strongest risk factor (OR 6.55; 95% Cl 2.36-18.17), but ACA-IgM above 20 MPL units also appeared to be a significant (p = 0.0159) risk factor (OR 3.90; 95% Cl 1.29-11.80). Furthermore, the presence of anti-β2GPI- and/or anti-prothrombin-antibodies in LAC positive patients (n = 60) does not increase the risk for thrombosis.The results showed that (i) the LAC assay correlates best with a history of both arterial and venous thrombosis and (ii) neither the anti-P2GPI ELISA nor the anti-prothrombin ELISA gives additional information for a thrombotic risk in SLE patients.
Nucleotide Structure and Characterization of the Murine Blood Coagulation Factor VII Gene
Authors: Idusogie Esohe , Rosen Elliot D , Carmeliet Peter , Collen Desire , Castellino Francis J 
Published: July 2018

SummaryThe gene encoding murine coagulation factor VII (fVII) has been cloned. Seven introns and eight exons are present, with the introns positioned as splice junctions between the major domain units of the protein. A total of 11,748 bp of the gene was sequenced, and included 1,077 bp of a 5’-flanking region, in which several high probability binding sites for liver transcription factors were present, as well as a CCAAT sequence and possible GC boxes. Primer extension analysis revealed that the major transcription start site was positioned only 9 residues upstream of the ATG initiation codon, thus providing a very short 5’-untranslated region of the gene. The sequence of the CAP site in the murine fVII gene matched exactly the consensus eukaryotic sequence. A total of 1,484 bp of 3’-flanking nucleotides included a probable polyadenylation site (ATTAAA) and an appropriately positioned downstream consensus sequence (AGTGTTTC) for the efficient formation of a 3’ terminus of mRNA. These results indicate that all elements are present for liver-based transcription of the gene for murine factor VII. The sequence and restriction endonuclease map of this gene will facilitate construction of fVII deficient mice and mice containing mutant fVII genes.
Age and Sex Dependent Regulation of the Factor IX Gene in Mice
Authors: Kurachi Sumiko , Hitomi Eri , Kurachi Kotoku 
Published: July 2018

SummaryPlasma factor IX and liver factor IX mRNA levels in two normal mouse strains (B6D2F1 and BALB/CJNIA) were determined in relation to aging and sex of the animals. With male B6D2F1 mice, mean plasma factor IX activity levels for the 14 and 21-22 month-old animals were found to be 124% and 226%, respectively, of the 5 month-old group. Similarly, liver factor IX mRNA levels for the same age animal groups were 145% and 227%, respectively, of the reference group. Mean plasma factor IX levels for the same age female animals were 132% and 175%, respectively, and were accompanied by similarly elevated liver factor IX mRNA levels, 119 and 175%, respectively, of the 5 month-old female group. Factor IX activity and mRNA levels for the 5,14 and 21-22 month-old female animal groups were lower than those of the corresponding male age groups by 25, 20 and 37%, and 20,36 and 38%, respectively. With BALB/CJNIA mice, similar correlation was observed between the advancing age and substantial elevations in the factor IX mRNA level as well as on the unequal factor IX mRNA levels in females and males.These results indicate that the plasma factor IX level in both male and female mice is greatly elevated with aging, in general agreement with a similar phenomenon observed for human populations, and that this increase is due to a similar elevation in the factor IX mRNA level in the liver. In mice, both factor IX activity and mRNA levels are significantly higher in males than in females, which has not been described for humans.
Distinct Patterns of Urokinase Receptor (uPAR) Expression by Leukemic Cells and Peripheral Blood Cells
Authors: Jardi Mercè , Inglés-Esteve Julia , Burgal Maria , Azqueta Carmen , Velasco Francisco , López-Pedrera Chary , Miles Lindsey , Félez Jordi 
Published: July 2018

SummaryThe urinary type plasminogen activator, urokinase (uPA) is localized on the cell surface through the binding of a specific receptor, the uPA receptor (uPAR). The uPA localization enhances plasmin formation on the cell surface and facilitates cell migration. The cellular and tissue distribution of uPAR is not fully established. We have analyzed uPAR expression in nine leukemic cell lines of distinct lineages and maturational states and correlated this with expression of plasminogen receptors, tissue-type plasminogen activator (tPA) receptors and LDL receptor-related protein (LRP). The most immature and least differentiated cell line (an erythro-myeloid cell line) and cells of lymphoid lineage, did not express uPAR, whereas cells differentiated along the myelo-monocytic pathway displayed this receptor. Plasminogen and tPA receptors were expressed by all leukemic cell lines and by all nucleated peripheral blood cells but B and T lymphocytes were negative for cell surface expression of both uPAR and LRP while monocytes and neutrophils were positive for expression of both uPAR and LRP. PMA stimulation induced surface expression of uPAR in lymphocytes but did not induce expression of LRP by these cells. In contrast, lymphoid cell lines were negative for uPAR expression even after PMA stimulation, indicating differences in regulation of uPAR expression between lymphocytes and lymphoid cell lines. The pattern of uPAR expression on leukemic cell lines was also studied on bone marrow blast cells from leukemic patients. Only the most mature myeloid cells expressed uPAR on their surfaces. In contrast, M3 leukemic cells and other blast cells displaying lymphoid markers such as TdT (+) and/or CD2 (+) did not express intracellular or cell-surface associated uPAR, indicating an heterogeneity among these promyelo-cytic cells and suggesting that uPAR may be a useful marker for leukemia typing. Myeloid blast cells from some patients contained intracellular pools of uPAR but displayed no receptor on the cell surface, suggesting that translocation may be a mechanism regulating uPAR expression in these cells. The comparison of uPAR expression between these cell lines and peripheral blood cells and it correlation with plasminogen receptors, tPA receptors and LRP expression offers new insights regarding potential mechanisms for regulation of uPA-uP-AR-mediated pericellular proteolysis.
PAICA: A Method for Characterizing Platelet-Associated Antibodies - Its Application to the Study of Idiopathic Thrombocytopenic Purpura and to the Detection of Platelet-bound c7E3
Authors: Macchi Laurent , Clofent-Sanchez Gisèle , Marit Gérald , Bihour Claude , Durrieu-Jais Catherine , Besse Pierre , Nurden Paquita , Nurden Alan T 
Published: July 2018

SummaryIn idiopathic thrombocytopenic purpura (ITP), autoantibodies reacting with antigens on the platelet membrane bring about accelerated platelet destruction. We now report PAICA (“Platelet-Associated IgG Characterization Assay”), a method for detecting autoantibodies bound to specific membrane glycoproteins in total platelet lysates. This monoclonal antibody (MAb) capture assay takes into account the fact that antibodies on circulating platelets may be translocated to internal pools as well as being on the surface. A total of twenty ITP patients were examined by PAICA, and the results compared with those obtained by measuring (i) serum antibodies bound to paraformaldehyde-fixed control platelets by ELISA, (ii) IgG bound to the surface of the patient’s own platelets by flow cytometry (PSIgG), (iii) total platelet-associated IgG (PAIgG) by ELISA and (iv) serum antibodies reacting with control platelets by MAIPA (“Monoclonal Antibody-specific Immobilization of Platelet Antigens”). Of twelve patients with elevated PAIgG, nine had increased PSIgG yet eleven reacted positively in PAICA. Of these, eight possessed antibodies directed against GP Ilb-IIIa, two against GP Ib-IX and one patient possessed antibodies directed against GP Ilb-IIIa and GP Ia-IIa respectively. Only seven of the patients possessed serum antibodies detectable by MAIPA. PAICA was also able to detect platelet-associated c7E3 (the chimeric form of Fab fragments of the MAb 7E3) following its infusion during antithrombotic therapy, when it proved more sensitive over a seven-day period than a MAIPA assay adapted for assessing surface-bound antibody. We propose that PAICA provides added sensitivity to the detection of platelet-associated antibodies in immune thrombocytopenias or following therapy with humanized MAbs.
A Novel Regulatory Epitope Defined by a Murine Monoclonal Antibody to the Platelet GPIIb-IIIa Complex (αIIbβ3 Integrin)
Authors: Tokuhira Michihide , Handa Makoto , Kamata Tetsuji , Oda Atsushi , Katayama Masahiko , Tomiyama Yoshiaki , Murata Mitsuru , Kawai Yohko , Watanabe Kiyoaki , Ikeda Yasuo 
Published: July 2018

SummaryWe characterized a murine monoclonal antibody, PT25-2 (IgG1), raised against washed human platelets. The antibody and its Fab fragments were both capable of inducing platelet aggregation in a fibrinogen-dependent manner and induced 125I-fibrinogen binding to unstimulated platelets (120,000 molecules/platelet at a 100 nM IgG concentration). The antibody immunoprecipitated the αIIbβ3 complex from lysates of iodinated platelets but did not react with the respective subunits when complex formation was disrupted by treatment with 5 mM EDTA at 37°C for 30 min. However, simply removing the extracellular divalent cation with EDTA had no effect on antibody binding indicating that the antibody’s epitope depends upon a conformational structure maintained by αβ subunit association. Antibody binding to unstimulated, washed platelets yielded binding parameters (Kd = 40 nM, Bmax = 100,000 molecules/platelet), which were found to be virtually unchanged when binding was performed using thrombin or RGDS-peptide-stimulated platelets. Thus, the PT25-2 antibody defines a novel regulatory epitope expressed by the αIIbβ3 integrin on unstimulated, quiescent platelets.
Platelets from Bleeding Simmental Cattle Have a Long Delay in both ADP-activated Expression of GpllB-IIIA Receptors and Fibrinogen-dependent Platelet Aggregation
Authors: Frojmovic Mony M , Wong Truman , Searcy Gene P 
Published: July 2018

SummaryWe have previously reported that platelets from bleeding Simmental cattle do not aggregate in vitro in response to ADP, collagen and calcium ionophore A23187, though calcium mobilization and myosin light chain phosphorylation do occur. The aggregation abnormality, measured by aggregometry, was ascribed to abnormal cytoskeletal expression, with the maximal numbers of activated GpIIb-IIIa receptors per platelet no different from that seen in normal bovine platelets activated with ADP. We have therefore sought to compare the kinetics of microaggregation with the rate of expression of GpIIb-IIIa receptors required for mediating fibrinogen (Fg)-dependent platelet aggregation, to provide a more direct molecular explanation for the aggregation abnormality. We compared aggregation kinetics of ADP-activated platelets using both aggregometry and particle counting to monitor microaggregation. Fibrinogen receptor expression was monitored with FITC-labelled human Fg and with the reporting antibody for activated GpIIb-IIIa, FITC-PAC1, using flow cytometry. The affected platelets show a marked delay in onset of microaggregation for ADP-activated platelets stirred with human Fg, paralleded by an unusual delay in activated GpIIb-IIIa receptor expression (DARE) for otherwise competent Fg binding. The on-rates for Fg binding to platelets maximally pre-activat-ed with PMA are identical for normal and affected platelets, whether comparing the binding of human or bovine Fg. The unique DARE syndrome explains the observed delay in aggregation of platelets from affected Simmental cattle and predicts the bleeding problems due to delayed binding of adhesive proteins.
Two Distinct Novel Splice Site Mutations in a Compound Heterozygous Patient with Protein S Deficiency
Authors: Yamazaki Tomio , Katsumi Akira , Okamoto Yoshihiro , Takafuta Toshio , Tsuzuki Shinobu , Kagami Kazuo , Sugiura Isamu , Kojima Tetsuhito , Fujimura Kingo , Saito Hidehiko 
Published: July 2018

SummaryGenetic analysis revealed two distinct novel splice site mutations in a compound heterozygous patient with protein S deficiency. The paternal mutation was a G-to-T transition at position -1 of the acceptor splice site of intron N (Mutation I), and the maternal mutation was a G-to-C transversion at position -1 of the donor splice site of intron C (Mutation II). Both splice site mutations decreased the mutated mRNA accumulation to the same extent, approximately 40% of the normal mRNA. However, the mutations were associated with different phenotypical expressions: the paternal mutant protein S was not detected in vivo, while the maternal mutant protein S was present in the plasma in reduced quantity. Because Mutation I caused a cryptic splicing in the mutated mRNA, resulting in a reading frameshift and premature termination, the predicted mutant protein S might be highly unstable. In contrast, Mutation II led to the substitution of Val46 by Leu, which might be much less deleterious for the synthesis, secretion and stability of the predicted mutant protein S. It was supposed that the different post-translational metabolisms produced the distinct phenotypical expressions of the mutations.
Thromboprophylaxis with Low Molecular Weight Heparin (Fragmin) in High Risk Pregnancies
Authors: Hunt Beverley J , Doughty Heidi-Ann , Majumdar G , Copplestone Adrian , Kerslake Sian , Buchanan Neil , Hughes Graham , Khamashta Munther 
Published: July 2018

SummaryVenous thromboembolic disease remains the commonest cause of maternal death. The management of thromboprophylaxis in high risk women during pregnancy is contentious. Low molecular weight heparins (LMW) have theoretical advantages compared with unfractionated heparin and warfarin but have been poorly studied in pregnancy. We report on the use of LMW heparin (Fragmin) as thromboprophylaxis in thirty four high risk pregnancies.All the women had a previous thrombosis or a thrombosis in their current pregnancy +/- a recognised thrombophilic state (eleven had the antiphospholipid syndrome).Fragmin was given subcutaneously to maintain trough anti-Xa activity of 0.15-0.2 U/ml and 2 h post injection levels of 0.4-0.6 U/ml. The levels were checked monthly during pregnancy. Most women required 5,000U Fragmin once daily during the first trimester unless they were greater than 100 kg at the start of pregnancy. The mean time for dosage increase was 20.5 week (S.D. 8.2). 26/34 pregnancies (76%) required twice daily at the end of pregnancy. Epidural anaesthesia was managed by omitting Fragmin dose or inserting the needle 6 hours after the previous Fragmin injection. There were no thromboembolic events, thrombocytopenias or excessive haemorrhage. One woman had osteoporotic vertebral collapse post partum, she had no other risk factors for osteoporosis.LWM heparin (Fragmin) appears to be efficacious in preventing recurrent thromboembolic disease in pregnant women at high risk, but it is notable that osteoporotic fractures occurred post partum in one woman. Further trials are required to determine optimal dosage and safety.
Tissue Factor (TF) and Urokinase Plasminogen Activator Receptor (uPAR) and Bleeding Complications in Leukemic Patients
Authors: López-Pedrera Chary , Jardí Merce , del Mar Malagón Maria , Inglés-Esteve Julia , Dorado Gabriel , Torres Antonio , Félez Jordi , Velasco Francisco 
Published: July 2018

SummaryTissue factor (TF) and urokinase receptor (uPAR) are key cellular receptors triggering, respectively, coagulation and fibrinolysis. Bleeding complications among leukemic patients have been related to an abnormal expression of TF by blast cells and/or to an abnormal fibrinolytic response. In this study the expression of TF and uPAR has been assessed in 18 acute non-lymphoblastic and 8 lymphoblastic leukemic blast cells using several methodological approaches. TF mRNA was evaluated by in situ hybridization and TF and uPAR antigen were evaluated immunologically in cell lysates and on the cell surface by flow cytometry. In addition, TF-procoagulant activity was measured in coagulation-based assays. The reliability of these methods was corroborated in six leukemic cell lines of different lineages and states of maturation. Disseminated intravascular coagulation was detected in two M3 leukemia patients whose blast cells expressed high amounts of TF. Hyperfibrinolysis was detected in one M1 and two M2 patients, whose blast cells displayed a high content of uPAR antigen, but no TF. Furthermore, M5 leukemia blast cells expressed both TF and uPAR, although no hemostatic defects or bleeding complications were detected in these patients. Taken together, although a limited number of patients was included in this study, these data suggest that in leukemia patients exhibiting bleeding, either TF or uPAR are expressed by their blast cells. However, the presence of these receptors does not necessarily imply the existence of a hemostatic disorder.
Genetic Diagnosis of Factor V Leiden Using Heteroduplex Technology
Authors: Bowen D J , Standen G R , Granville S , Bowley S , Wood N A P , Bidwell J 
Published: July 2018

SummaryA new genetic test has been developed for detection of the mutation known as factor V Leiden. The test employs heteroduplex technology and comprises a single PCR reaction followed immediately by PCR product analysis. It therefore represents the minimum practical route from blood/tissue sample to genetic result. A cohort of 100 patients with a history of thrombosis have been screened using both the new heteroduplex test and a previously described PCR-restriction endonuclease test. Results gave 100% correlation: normals 75 (75%), heterozygotes 24 (24%) and homozygotes 1 (1%). The heteroduplex test has been shown to give straightforward diagnosis in three different analytical systems: standard polyacrylamide gel electrophoresis (PAGE), mini-gel PAGE and capillary electrophoresis. The latter system is semiautomated, therefore rapid through-put of large sample numbers is now · possible.
Utilization of Dilute Russell’s Viper Venom Time to Detect Autoantibodies against β2-Glycoprotein I which Express Anticoagulant Activity in the Presence but not in the Absence of Exogenous Phospholipids
Authors: Pengo V , Balestrieri G , Tincani A , Spatola L , Biasiolo A , Brocco T 
Published: July 2018

SummaryLupus anticoagulant (LA) is a general term to define immunoglobulins interfering with phospholipid-dependent coagulation tests. It is now clear that the phospholipid-dependence of some LA is related to the presence of the phospholipid-binding plasma protein β2-glycoprotein I β2-GPI) and that autoantibodies to β2-GPI might represent a specific category of LA. To verify this hypothesis we have purified IgG autoantibodies to β2-GPI from plasma of 6 patients with antiphospholipid antibody syndrome, by means of agarose-immobilized human β2-GPI. All 6 preparations tested positive in anti-β2-GPI IgG antibody ELISA and showed a marked LA activity by prolonging dilute Russell Viper Venom Time (dRVVT) from a minimum of 5.3 s in patient # 1 to a maximum of 41.1 s in patient # 3. These IgG preparations behaved as typical LA, with this activity tending to disappear in the presence of increasing phospholipid (PL) concentrations. Moreover, the LA activity of the IgG preparations was not detectable in the absence of PL, in which case the ratio between dRVVT obtained in the presence and absence of IgG autoantibodies to β2-GPI was close to 1. This pattern was confirmed by using plasma from patients with antiphospholipid antibody syndrome testing positive for anti-β2-GPI IgG antibodies. These findings suggest that dRVVT performed both in the presence and absence of PL might constitute a sensitive screening test to detect specific antibodies with LA activity.
Effect of a 15-Minute Infusion of DDAVP on the Pharmacokinetics and Pharmacodynamics of ™REVASC during a Four-Hour Intravenous Infusion in Healthy Male Volunteers
Authors: Amin Dipti M , Mant Timothy G K , Walker Stephen M , Kerry Roger , Lloyd Peter , Lefèvre Gilbert , Close Philippe 
Published: July 2018

SummaryPlasma pharmacokinetics, effect on coagulation parameters, and safety and tolerability of an intravenous infusion of ™REVASC before, during and after a DDAVP infusion were investigated.Twelve healthy volunteers were given an intravenous bolus dose followed by a constant rate four-hour infusion of ™REVASC. Fifteen-minute infusions of 0.9% saline and DDAVP were started two and three hours respectively after the start of the ™REVASC infusion.Plasma ™REVASC concentrations were not affected by either the saline or DDAVP infusion. ™REVASC infusion produced an increase in APTT which plateaued between 0.5 and 3 hours. After the DDAVP infusion there was a tendency towards a new lower plateau whilst the ™REVASC infusion continued. There were no serious adverse events or bleeding episodes throughout the study.In conclusion, the co-administration of intravenous DDAVP has no effect on the plasma pharmacokinetics of ™REVASC and partially reverses the ™REVASC-induced increase in APTT. This may represent a role for DDAVP in the partial reversal of anticoagulation induced by ™REVASC.