bluuebunny/crossref_metadata_2025 huggingface dataset:
Recurrent Venous Thrombosis and Markers of Inflammation
Authors: van Aken Benien , den Heijer Martin , Bos Gerard , van Deventer Sander , Reitsma Pieter
Published: March 2018

Inflammatory processes may play a key role in venous thrombosis, by inducing a procoagulant state through the action of cytokines and chemokines on monocytes and endothelial cells. Plasma concentrations of three inflammatory mediators, interleukin 6 (IL-6), interleukin 8 (IL-8) and monocyte chemotactic protein 1 (MCP-1), that mediate the cross-talk between inflammation and coagulation, were measured in 182 subjects with recurrent venous thrombosis and 350 healthy subjects recruited through a general practice. Elevated levels of IL-6 (>90th percentile of the control group) were detected in 25.8% of the patients with venous thrombosis in comparison with 10% (by definition) of the controls [odds ratio 2.4 (95%CI 1.5-3.8)]. In 21.5% of the patients elevated plasma levels of IL-8 (>90th percentile) were determined [odds ratio 2.0 (95%CI 1.2-3.5)]. Elevated levels of MCP-1 (>90th percentile) were detected in 24.1% of the patients [odds ratio 1.9 (95%CI 1.2-3.2)]. This is the first large clinical study showing that an increase in inflammatory mediators is associated with venous thrombosis. Future prospective studies are necessary to clarify the causal nature of the inflammatory process with respect to venous thrombosis.
Exclusion of Known Protease Activated Receptors in Factor VIIa-induced Signal Transduction
Authors: Thastrup Ole , Hagel Grith , Sørensen Brit , Freskgård Per-Ola , Rao L. Vijaya , Ezban Mirella , Petersen Lars
Published: March 2018

The protease activity is mandatory for intracellular activities induced by coagulation factor VIIa (FVIIa), and in this way it resembles signal transduction induced by thrombin and trypsin caused by specific, proteolytic cleavage of protease activated receptors (PARs). The mechanism for FVIIa-induced signal transduction is, however, not known although a mechanism involving PAR cleavage has been deduced from studies of cytosolic Ca2+ release and p44/p42 mitogen activated protein kinase (MAPK) activation. In the present work we have examined the possibilities that i) FVIIa-induced signal transduction involves the activation of one of the four known PARs, or ii) exposure of cells to FVIIa releases a soluble ligand that is responsible for MAPK activation. For this purpose, we evaluated the effects of FVIIa, thrombin, FXa, trypsin and PAR agonist peptides on the Ca2+ release and MAPK activation in tissue factor-(TF) transfected baby hamster kidney (BHK[+TF]) cells and Madin-Darby canine kidney (MDCK) cells. FVIIa induced a significant MAPK signal in BHK(+TF) cells and in MDCK-I and -II cells whereas no MAPK activation was observed with thrombin, FXa or PAR agonist peptides. Thrombin, trypsin, PAR-1 and PAR-2 agonist peptides induced a prominent Ca2+ response in both cell types. In contrast the cells did not respond with a detectable Ca2+ signal when treated with FVIIa. These results suggest that the intracellular activity induced by FVIIa is distinctly different from that induced by trypsin, thrombin and FXa not involving any of the known PARs. Conditioned medium from BHK(+TF) cells treated with FVIIa failed to induce a MAPK response in untreated BHK(+TF) cells when FVIIa was removed by immunoadsorption from the medium prior to its transfer to the untreated BHK(+TF) cells. Although it is not possible entirely to exclude a transient response close to the cell surface, the data suggest that the intracellular response was not induced by an autocrine release of a soluble mediator to the medium.
The Thrombogram: Monitoring Thrombin Generation in Platelet Rich Plasma
Authors: Giesen Peter , Ramjee Manoj , Wagenvoord Rob , Béguin Suzette , Hemker Coenraad
Published: March 2018

A method is described in which thrombin activity in clotting plasma can be monitored through the continuous measurement of the fluorescent split-product of the substrate Z-Gly-Gly-Arg-AMC. The signal is not impaired by turbidity; therefore proper measurement is not disturbed by the occurrence of a clot or the presence of platelets and direct measurement in platelet rich plasma is possible.
A Functional Assay Suggests that Heterodimers Exist in Two C-Terminal γ-Chain Dysfibrinogens: Matsumoto I and Vlissingen/Frankfurt IV
Authors: Hogan Kelly , Lord Susan , Okumura Nobuo , Terasawa Fumiko , Galanakis Dennis , Scharrer Inge , Gorkun Oleg
Published: March 2018

Because it contains three pairs of polypeptides, fibrinogen isolated from heterozygous individuals is expected to be a mixture of homodimers and heterodimers. Nevertheless, heterozygous individuals with only homodimers have been identified. We synthesized two recombinant fibrinogens with the mutations from fibrinogen Vlissingen/ Frankfurt IV (γΔ319, 320) and Matsumoto I (γD364H), both identified in heterozygous individuals. We found that polymerization of these fibrinogens was undetectable in 30 min; polymerization of a 1:1 mixture of variant and normal fibrinogen was the same as polymerization of a 1:1 mixture of buffer and normal fibrinogen; polymerization of either plasma fibrinogen was markedly impaired when compared to the 1:1 mixture of the respective variant and normal fibrinogens. We conclude that each plasma fibrinogen is a mix of homodimers and heterodimers, such that the incorporation of heterodimers into the fibrin clot impairs polymerization. We suggest that incorporation of heterodimers can induce clinical symptoms.
In Vivo Penetration of Experimentally Produced Clots by Monoclonal Antibodies
Authors: Edgell T. A. , Webbon P. M. , Gaffney P. J. , McEvoy F. J.
Published: March 2018

Antifibrin monoclonal antibodies show potential as clot targeting agents for diagnosis and possibly therapy in thrombotic disease. To be effective the antibody must bind to the fibrin component of the clot. The ability of two antifibrin mabs (NIB 1H10 and NIB 12B3) to penetrate occlusive clots in vivo was investigated Both mabs react with human fibrin but not with human fibrinogen nor with the fibrin or fibrinogen from the species used in this study.

Two heterologous animal (sheep and rabbit) thrombus models were used. Clots in both cases were made within isolated vein segments using a mixture of human and native fibrinogen. The clots in sheep veins were observed radiographically and found to be occlusive for a mean of 4.2 ± 2.2 days and thereafter appeared only partially occlusive. When targeted in their occlusive phase 131I labelled mab accumulated in the clot reaching a maximum ratio of 1.82 ± 0.42 when compared to counts in homologous sheep clots in the contralateral limb. It was confirmed in the rabbit jugular vein model that total occlusivity did not prevent antibody accumulation in the heterologous clot by injecting the fibrin specific mab IH10 and examining the clot excised after 1, 6 and 24 h using immunofluorescence. In a further series of similar experiments 125I labelled mab 1H10 was used and detected using autoradiography. Both sets of experiments indicated that penetration of occlusive clots by the antibody occurred and that considerable accumulation was present at 6 and 24 h.

The results indicate that a circulating antibody can readily gain access to experimentally produced clots in occluded veins.
Demonstration of an Association between Chlamydia pneumoniae Infection and Venous Thromboembolic Disease
Authors: Lozinguez Olivier , Arnaud Emmanuel , Belec Laurent , Nicaud Viviane , Alhenc-Gelas Martine , Fiessinger Jean-Noël , Aiach Martine , Emmerich Joseph
Published: March 2018

Chlamydia pneumoniae infection has been linked to atherosclerosis, but a possible relationship with venous thromboembolism (VTE) has not been sought. We determined circulating anti-C. pneumoniae antibody levels in patients with VTE. We studied 176 case patients with objectively diagnosed VTE and 197 age-and sex-matched healthy controls, in a retrospective study. Acquired risk factors for VTE and frequent predisposing genetic factors (factor V Arg 506 Gln and factor II G 20210 A mutations) were assessed in all the subjects. Anti-C. pneumoniae IgG antibodies were determined by microimmunofluorescence. All positive plasma samples (titer ≥128) were precisely quantified and tested for the presence of specific IgM antibodies. Fiftyfour percent of the cases and 15.9% of the controls had specific IgG titers of at least 256 (p <0.0001). The crude odds ratio for VTE was 6.2 (95% CI, 3.8-10.1), and rose to 7.7 (4.5-13.2) after excluding subjects carrying the factor V Arg 506 Gln or factor II G 20210 A mutations. The odds ratio for VTE increased with the IgG titer: the adjusted odds ratios were 2.1 (95% CI, 1.1-4.1), 5.3 (2.7-10.6) and 33.0 (4.4-248.4) for titers of 256, 512 and 1024, respectively. Only one subject (a case patient) with a high IgG titer (≥256) also had specific IgM. High titers of anti-C. pneumoniae IgG antibodies are frequently found in patients with previous venous thromboembolism. This association deserves to be confirmed in other case-control studies and prospective studies.

All authors have reviewed the manuscript and agree with its content.
The Bβ-sheet in the PAI-1 Molecule Plays an Important Role for Its Stability
Authors: Sui Guang-Chao , Wiman Björn
Published: March 2018

We have investigated the B β-sheet in PAI-1 regarding its role for the stability of the molecule. The residues from His219 to Tyr241 (except for Gly230 and Pro240), covering the s2B and s3B strands, and in addition His185 and His190 were substituted by amino acids with opposite properties. The 23 generated single-site changed mutants and also wild type PAI-1 (wtPAI-1) were expressed in E. coli. Subsequently they were purified by heparin-Sepharose and anhydrotrypsin agarose affinity chromatographies. The stability of the purified PAI-1 variants was analyzed at 37° C and at different pHs (5.5, 6.5 or 7.5). At pH 7.5 and 37° C, single substitutions of the residues in the central portions of both strands 2 and 3 in the B β-sheet (Ile223 to Leu226 on s2B and Met235 to Ile237 on s3B), caused a significant decrease in stability, yielding half-lives of about 10–25% as compared to wtPAI-1. On the other hand, mutations at both sides of the central portion of the B β-sheet (Tyr221, Asp222, Tyr228 and Thr232) frequently resulted in an increased PAI-1 stability (up to 7-fold). While wtPAI-1 exhibited prolonged half-lives at pH 6.5 and 5.5, the PAI-1 variant Y228S was more stable at neutral pH (half-life of 9.6 h at pH 7.5) as compared to its half-life at pH 5.5 (1.1 h). One of the 4 modified histidine residues (His229) resulted in a variant with a clearly affected stability as a function of pH, suggesting that it may, at least in part, be of importance for the pH dependence of the PAI-1 stability. Thus, our data demonstrate that the B β-sheet is of great importance for the stability of the molecule. Modifications in this part causes decreased or increased stability in a certain pattern, suggesting effects on the insertion rate of the reactive center loop into the A β-sheet of the molecule.
Homocysteine as a Risk Factor for Restenosis after Coronary Angioplasty
Authors: Kurihara Hiroki , Kuwaki Tomoyuki , Hamada Chikuma , Kitaoka Masao , Suzuki Shin , Yazaki Yoshio , Nagai Ryozo , Morita Hiroyuki
Published: March 2018

We examined the relationship between plasma homocysteine levels and restenosis after PTCA (Percutaneous transluminal coronary angioplasty) to investigate whether plasma homocysteine levels can be a predictor of restenosis after PTCA. One hundred and twelve male patients who have undergone a successful elective PTCA were consecutively enrolled and plasma homocysteine levels were measured at the time of follow-up angiography. Plasma homocysteine levels in patients with restenosis were significantly higher than those in patients without restenosis (15.0 ± 3.9 vs. 13 ± 2.9 µmol/L; P = 0.011). The difference was augmented when diabetic patients were selectively studied. The comparison between restenosis group and non-restenosis group indicated the threshold effect of hyperhomocysteinemia. These results suggest that plasma homocysteine is a potential risk factor of restenosis after PTCA, and therapeutic strategy targeted against hyperhomocysteinemia may be beneficial for preventing restenosis.
The Influence of (R)- and (S)-Warfarin, Vitamin K and Vitamin K Epoxide upon Warfarin Anticoagulation
Authors: Edwards Clive , Butler Timothy , Wynne Hilary , Kamali Farhad
Published: March 2018

The contribution of (R)and (S)-warfarin enantiomers, vitamin K and vitamin K epoxide and patient factors to inter-individual variability in daily warfarin requirements were examined in a group of 73 patients. Simple correlation analysis showed a significant positive relationship between INR values and plasma (S)-warfarin concentrations (r = 0.25; p = 0.038). Multivariate analysis for relationships with INR demonstrated a highly significant positive relationship between INR and (S)- warfarin (p = 0.004) and plasma vitamin K epoxide concentrations (p = 0.028), and a significant negative relationship between INR and plasma vitamin K concentrations (p = 0.034). Twenty five percent of variation in INR could be explained by these variables (adjusted R2 = 0.25). Correlation analysis of data showed that warfarin dosage was significantly and negatively correlated with patient age (r = −0.42; p <0.0001). Patient age accounted for 25% of variation in warfarin dosage requirements (R2 = 0.25). The combined effects of age and vitamin K appear to account for much of the inter-individual variability in warfarin dosage requirements.
Effect of Urinary Protein C Inhibitor on Lipopolysaccharide-induced Disseminated Intravascular Coagulation in Rats
Authors: Izutani Wakako , Komurasaki Yoshikazu , Fujita Mitsugu
Published: March 2018

The effect of urinary protein C inhibitor (uPCI) on disseminated intravascular coagulation (DIC) was investigated using an experimental DIC in rats. uPCI (0.5 and 1.0 mg/kg) was continuously administrated into the left femoral vein of the rats with lipopolysaccharide (50 mg/kg)-induced DIC. In all doses, uPCI significantly prevented the drastic changes in the parameters such as fibrinogen concentration, activated partial thromboplastin time (APTT), prothrombin time (PT), fibrin/fibrinogen degradation products (FDP) level, aspartate aminotransferase (AST) level and alanine aminotransferase (ALT) level. Furthermore, uPCI significantly inhibited the increase in the levels of plasma kallikrein and thrombin which act not only as the procoagulant proteases but also as the chemotactic factors to neutrophils and monocytes. These results show that uPCI may prevent hypercoagulation, the induction of secondary fibrinolysis and organ failure in the DIC model. Therefore, uPCI may be a useful agent for the clinical treatment of DIC.
Fluvastatin Inhibits Basal and Stimulated Plasminogen Activator Inhibitor 1, but Induces Tissue Type Plasminogen Activator in Cultured Human Endothelial Cells
Authors: Mussoni Luciana , Banfi Cristina , Sironi Luigi , Arpaia Magda , Tremoli Elena
Published: March 2018

The effects of fluvastatin, a synthetic hydroxymethylglutaryl coenzyme A (HMG-CoA) inhibitor, on the biosynthesis of tissue plasminogen activator (t-PA) and of its major physiological inhibitor (plasminogen activator inhibitor type 1, PAI-1) were investigated in cultured human umbilical vein endothelial cells (HUVEC). Fluvastatin (0.1 to 2.5 µM), concentration-dependently reduced the release of PAI-1 antigen by unstimulated HUVEC, subsequent to a reduction in PAI-1 steady-state mRNA levels and de novo protein synthesis. In contrast, it increased t-PA secretion.

The drug also reduced PAI-1 antigen secreted in response to 10 µg/ml bacterial lipopolysaccharide (LPS), 100 U/ml tumour necrosis factor α (TNFα) or 0.1 µM phorbol myristate acetate (PMA).

Mevalonate (100 µM), a precursor of isoprenoids, added to cells simultaneously with fluvastatin, suppressed the effect of the drug on PAI-1 both in unstimulated and stimulated cells as well as on t-PA antigen. Among intermediates of the isoprenoid pathway, all-trans-geranylgeraniol (5 µM) but not farnesol (10 µM) prevented the effect of 2.5 µM fluvastatin on PAI-1 antigen, which suggests that the former intermediate of the isoprenoid synthesis is responsible for the observed effects.
Assessment of Primary Hemostasis by PFA-100® Analysis in a Tertiary Care Center
Authors: James Andra , Thames Elizabeth , Moore Karen , Greenberg Charles , Ortel Thomas
Published: March 2018

We evaluated the utility of the PFA-100® platelet function analyzer in identifying disorders in platelet function and/or von Willebrand factor (vWF) in patients with various systemic disorders being followed at a tertiary care center. Closure times were determined with collagen/ ADP (CADP) and collagen/epinephrine (CEPI) cartridges for 305 patients, and abnormal results were further evaluated with platelet aggregometry and vWF analysis. Prolonged CADP and/or CEPI closure times were identified in 114 patients (37.3%), but most were isolated prolonged CEPI closure times predominantly due to aspirin therapy (79 patients). Prolonged CADP closure times were most frequently due to qualitative platelet defects and/or decreased vWF levels. Prolonged CADP closure times were encountered most frequently in patients with sickle cell disease and were associated with a decreased hematocrit. This study demonstrated that the PFA-100® analyzer can accurately assess vWF-dependent platelet function and detect other platelet defects under high shear stress in complex patient populations.
A Collaborative Study to Establish the 2nd International Standard for Fibrinogen, Plasma
Authors: Whitton C. M. , Sands D. , Gaffney P. J. , Hubbard A. R.
Published: March 2018

An International Collaborative Study involving 12 laboratories in 7 different countries was undertaken in order to replace the 1st International Standard (IS) for Fibrinogen, Plasma (89/644). The candidate replacement standard was the ampouled and freeze-dried residue of solvent/detergent treated plasma and was calibrated as coded duplicates (A and B) versus the 1st IS Fibrinogen, Plasma by automated Clauss assay and by a recommended clot collection (gravimetric) assay. This latter method had been used to calibrate the 1st IS Fibrinogen, Plasma.

Comparing the ratios of the potency estimates of sample A to sample B (the coded duplicates), all of the laboratories obtained a ratio within 5% of the expected value of 1.0 by automated Clauss assay, which suggests that the laboratories were able to perform this assay well. Scrutiny of the data obtained from the gravimetric assays revealed that in almost all cases the results were invalid. The results of these assays are included in this report but clearly should be treated with caution and indeed produced significantly lower mean estimates of potency than the other assay methods. The overall geometric mean of all estimates of potency of the proposed 2nd IS Fibrinogen, Plasma (98/612) is 2.19 mg/ampoule by the automated Clauss assay. These data have been presented to the Fibrinogen Sub-Committee of the Standardisation and Scientific Committee (SSC) of the International Society on Thrombosis and Haemostasis (ISTH) (Washington, DC, August 1999), which recommended the establishment of 98/612 as the 2nd IS Fibrinogen, Plasma. This report has been presented to the Expert Committee on Biological Standardisation of the World Health Organisation (ECBS-WHO) at their 1999 session and 98/612 was established as the 2nd IS Fibrinogen, Plasma with a potency of 2.2 mg/ ampoule.
Endothelial Cell Seeding on Crosslinked Collagen: Effects of Crosslinking on Endothelial Cell Proliferation and Functional Parameters
Authors: Wissink M. J. B. , van Luyn M. J. A. , Beernink R. , Dijk F. , Poot A. A. , Engbers G. H. M. , Beugeling T. , van Aken W. G. , Feijen J.
Published: March 2018

Endothelial cell seeding, a promising method to improve the performance of small-diameter vascular grafts, requires a suitable substrate, such as crosslinked collagen. Commonly used crosslinking agents such as glutaraldehyde and formaldehyde cause, however, cytotoxic reactions and thereby hamper endothelialization of currently available collagen-coated vascular graft materials.

The aim of this study was to investigate the effects of an alternative method for crosslinking of collagen, using N-(3-dimethylaminopropyl)-N’-ethylcarbodiimide (EDC) in combination with N-hydroxysuccinimide (NHS), on various cellular functions of human umbilical vein endothelial cells (HUVECs) in vitro. Compared to non-crosslinked type I collagen, proliferation of seeded endothelial cells was significantly increased on EDC/NHS-crosslinked collagen. Furthermore, higher cell numbers were found with increasing crosslink densities. Neither the morphology of the cells nor the secretion of prostacyclin (PGI2), von Willebrand factor (vWF), tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI-1) was affected by the crosslink density of the collagen substrate. Therefore, EDC/NHScrosslinked collagen is candidate substrate for in vivo application such as endothelial cell seeding of collagen-coated vascular grafts.
Deficiency Causing Mutations and Common Polymorphisms in the Factor XIII-A Gene
Authors: Muszbek L.
Published: March 2018

Blood coagulation factor XIII (FXIII), for its unique features, used to be considered a stepchild among clotting factors. In contrast to other proenzyme clotting factors, it is the precursor of a transglutaminase and not of a proteolytic enzyme. By cross-linking peptide-bound glutamine and lysine side chains transglutaminases make, rather than break, peptide bonds. Activated FXIII (FXIIIa) cross-links fibrin α-chains and γ-chains and covalently attaches α2-plasmin inhibitor to fibrin α-chains to strengthen fibrin mechanically and to protect it from fibrinolysis. In addition to being a clotting factor, FXIII is also an intracellular proenzyme present in platelets and monocytes/macrophages. The plasma factor is of heterotetrameric structure consisting of two potentially active A (FXIII-A) and two inhibitory/protective B (FXIII-B) subunits (A2B2), while its cellular counterpart is a dimer of FXIII-A. Plasma FXIII is activated by the concerted action of thrombin and Ca2+. Thrombin cleaves FXIII-A at Arg37-Gly38, then in the presence of Ca2+ FXIII-B dissociates and FXIII-A assumes an active configuration (reviewed in ref. 1).
Low Molecular Weight Heparin (Enoxaparin) Versus Oral Anticoagulant Therapy (Acenocoumarol) in the Long-Term Treatment of Deep Venous Thrombosis in the Elderly: a Randomized Trial
Authors: Escribá A. , Maluenda M. P. , Rubio M. , Margalet I. , Lezana A. , Gallego J. , Ribera J. M. , Veiga F.
Published: March 2018

This study aims to establish the relative effectiveness and safety of low molecular weight heparin in elderly patients with venous thrombosis in order to find an alternative to oral anticoagulant therapy with less bleeding complications in the long-term treatment of deep venous thrombosis (DVT).

One hundred consecutive elderly patients (>75 years old) with venographically demonstrated proximal DVT were included in a randomized trial. All patients were treated for ten days with adjusted doses of intravenous heparin. Informed consent was obtained and on the eight day, patients were randomly allocated to receive acenocoumarol (INR 2.0-3.0) or subcutaneous enoxaparin (4000 anti-Xa units once a day) for three months. All patients were followed-up clinically and venographically for a one year period. The results were analyzed with Fisher’s exact test or chi-square test as appropriate.

During the treatment and surveillance period, 6 of the 50 patients (12%) who received acenocoumarol and 8 of the 50 patients (16%) who received enoxaparin had new episodes of venous thromboembolism confirmed by objective testing (p = 0.6; 95% CI for the difference: −19.5 to 11.5). Hemorrhagic complications occurred in six of the 50 patients (12%) who received acenocoumarol and in one (2%) of those on enoxaparin (p = 0.1; 95% CI for the difference: -1.8 to 21.8). Vertebral fractures developed in 2 patients (4%) in the enoxaparin group (p = 0.5; 95% CI for the diference: −11.4 to 3.4).

These results show that fixed dose enoxaparin seems to be effective and safe in the long-term treatment of proximal DVT in the elderly. In comparison with oral anticoagulants, the findings are inconclusive due to the wide confidence intervals for differences between outcomes, however they suggest that the former may have less bleeding complications with similar efficacy.
Increased Fibrinogen Levels and Hemostatic Abnormalities in Patients with Arteriolar Nephrosclerosis: Association with Cardiovascular Events
Authors: Zingaro Laura , Catena Cristiana , De Marchi Sergio , Sechi Leonardo
Published: March 2018

Increased plasma fibrinogen levels and hemostatic abnormalities suggestive of a prothrombotic state are present in patients with endstage renal failure and could contribute to increased cardiovascular morbidity in these patients. We investigated the relationship between abnormalities of the hemostatic system and the degree of renal failure and whether these abnormalities are associated with increased prevalence of cardiovascular events in patients with arteriolar nephrosclerosis. In 425 patients recruited at a hypertension clinic we assessed the renal function by creatinine clearance, urinary protein excretion, and microalbuminuria, the prevalence of atherosclerotic disease, and measured prothrombin time, activated partial thromboplastin time, fibrinogen, prothrombin fragment 1+2 (F1+2), D-dimer, and antithrombin. Early impairment of renal function (creatinine clearance, 30 to 89 ml/min per 1.73 m2 of body surface area) caused by arteriolar nephrosclerosis was found in 172 patients. Patients with early renal failure were significanly older and had significantly greater values of blood pressure, plasma fibrinogen, F1+2, and D-dimer than patients with normal renal function. Elevated D-dimer and fibrinogen levels were independently associated with the presence of decreased creatinine clearance. Log fibrinogen, log F1+2, and log D-dimer were inversely correlated with creatinine clearance. The prevalence of coronary artery, cerebrovascular, and peripheral vascular disease was significantly greater in patients with mild renal failure than in those with normal renal function. Elevated levels of fibrinogen and D-dimer were associated with the presence of atherosclerotic disease independent of renal function and other risk factors. In conclusion, changes in hemostatic parameters occur early in the course of renal failure in patients with arteriolar nephrosclerosis, suggesting a prothrombotic state that may contribute to the risk for atherosclerotic disease at all levels of renal function.
Contribution of the Cystathionine β-Synthase Gene (844ins68) Polymorphism to the Risk of Early-onset Venous and Arterial Occlusive Disease and of Fasting Hyperhomocysteinemia
Authors: de Franchis Raffaella , Fermo Isabella , Mazzola Giuseppina , Sebastio Gianfranco , Di Minno Giovanni , Coppola Antonio , Andria Generoso , D’Angelo Armando
Published: March 2018

The frequency of the heterozygous 844ins68 mutation of the cystathionine β-synthase (CBS) gene and of its association with the homozygous C677T transition of the methylenetetrahydrofolate reductase (MTHFR) gene, plasma fasting tHcy, folate and vitamin B12 levels were evaluated in 309 consecutive patients with objectively diagnosed early-onset venous (n = 200) or arterial thromboembolic disease (n = 109) recruited over 25 months in Milan (North Italy) and Naples (South Italy). The above gene polymorphisms were also evaluated in a population of 787 unmatched controls, 204 of whom – similar to patients for age- and sex-distribution – had fasting tHcy, vitamins and activated protein C resistance measured in their plasma.

Moderate fasting hyperhomocysteinemia was detected in 15.5% of patients and in 5.9% of 204 controls (Mantel-Haenszel OR after stratification for type of occlusive disease and gender: 2.88; 1.48–5.32). The frequencies of the 677TT mutation of the MTHFR gene and of the heterozygous 844ins68 insertion of the CBS gene were not significantly different in the patient (19.4% and 6.9%) and the control population (16.5% and 7.8%), but the association of the two gene polymorphisms – found in 3.9% of patients and in 1.1% of controls – was significantly associated with an increased risk of venous or arterial occlusive diseases (RR = 3.63; 1.48–8.91). The MTHFR 677TT mutation (RR: 6.92; 3.86–12.4) and its association with the 844ins68 insertion (RR: 21.9; 8.35–57.4), but not the isolated insertion (RR: 0.71), were more frequent in patients and controls with fasting hyperhomocysteinemia than in normohomocysteinemic subjects, irrespective of the type of occlusive disease (venous or arterial). When adjusted for determinants of hyperhomocysteinemia in the patient and the control populations (generalized linear model), fasting tHcy levels were significantly higher in subjects with association of the two gene abnormalities (24.2 ± 3.8 µmol/L) than in subjects with the MTHFR 677TT mutation only (14.0 ± 5.8 µmol/L, p = 0.004). Activated protein C resistance was significantly more prevalent in venous patients (9.9%) than in controls (3.9%, OR = 2.69; 1.08–6.88). Six of 21 venous patients with APCresistance also had hyperhomocysteinemia (RR = 5.04; 0.68–37.6), but isolated fasting hyperhomocysteinemia retained statistical significance for the association with venous occlusive disease (RR = 2.84; 1.34–6.01).

Heterozygosity for the 844ins68 mutation of the CBS gene is not per se a risk factor for premature arterial and/or venous occlusive diseases. However, when detected in combination with thermolabile MTHFR, it increases by almost 4-fold the risk of occlusive diseases (arterial and/or venous), by increasing the risk and the degree of fasting hyperhomocysteinemia.
Effect of Val34Leu Polymorphism on the Activation of the Coagulation Factor XIII-A
Authors: Mikkola H. , Szôke G. , Haramura G. , Kárpáti L. , Balogh I. , Lassila R. , Muszbek L. , Palotie A. , Wartiovaara U.
Published: March 2018

Coagulation factor XIII (FXIII) is a protransglutaminase involved in the last step of the coagulation cascade by stabilising the fibrin clot. Recently, a common variation (FXIII Val34Leu) has been associated with a decreased risk of myocardial infarction and deep venous thrombosis. Val34Leu is critically located near the thrombin activation site of FXIII-A. In this study we investigated its effects on the activation of FXIII. Both recombinant and platelet-derived FXIII Val34Leu variants were shown to be more susceptible to thrombin cleavage than the wild type FXIII. The rate of enzymatic activation of FXIII Val34Leu was found increased, however, the specific activity of fully activated wild type FXIII and the Val34Leu mutant did not differ. During the course of thrombin-induced activation of FXIII fibrin γ-chain dimerisation and α-chain polymerisation developed more rapidly with the Val34Leu mutant. The increased rate of fibrin stabilisation brought about by the Val34Leu FXIII seems to be paradoxically associated with a protective effect against pathological thrombosis.

Abbreviations: AP, activation peptide of factor XIII; FXIII, blood coagulation factor XIII; FXIII-A, factor XIII subunit A; FXIII-A’, proteolytically activated subunit A; FXIII-B, factor XIII subunit B; SDS PAGE, sodium dodecyl sulfate polyacrylamide gel electrophoresis
Antibodies to β2-Glycoprotein I Associated with Antiphospholipid Syndrome Suppress the Inhibitory Activity of Tissue Factor Pathway Inhibitor
Authors: Salemink Irene , Blezer Ron , Willems George , Galli Monica , Bevers Edouard , Lindhout Theo
Published: March 2018

Anionic phospholipid membranes have a dual role in blood coagulation: they are essential for the initiation and propagation as well as for the limitation and termination of the blood coagulation process. Patients with the anti-phospholipid syndrome (APS) carrying antibodies against complexes of anionic phospholipids and plasma proteins, show in vitro inhibited phospholipid dependent coagulation reactions, whereas in vivo the presence of these antibodies is associated with an increased risk of thrombosis. In this study we focussed on the effects of these anti-phospholipid antibodies on the regulation of TF-mediated factor Xa (FXa) generation in plasma. We hypothesized that anti-phospholipid antibodies interfere with the phospholipiddependent inhibition by tissue factor pathway inhibitor (TFPI) of TFinduced coagulation. Indeed, total-IgG, anti-cardiolipin-IgG (aCL) and anti-β2GPI-IgG, isolated from patient plasmas, all stimulated TF-induced FXa generation in normal plasma. This enhanced FXa generation was not observed when the patient’s IgG was depleted of anti-β2GPI-IgG or when normal plasma was depleted of β2GPI or TFPI. Taken together, these data indicate that antibodies to β2GPI, circulating in patients with APS, suppress TFPI-dependent inhibition of TF-induced coagulation, which results in an increased FXa generation.
A Comparison of Two Sodium Citrate Concentrations in Two Evacuated Blood Collection Systems for Prothrombin Time and ISI Determination
Authors: Chantarangkul V. , Tripodi A. , van den Besselaar A. M. H. P.
Published: March 2018

The prothrombin time is usually measured in citrated plasma. The W.H.O. recommended concentration of sodium citrate for blood collection for laboratory control of oral anticoagulant therapy is 0.109 M. Some evacuated blood collection systems include 0.105 M sodium citrate. The purpose of the present study was to establish the difference in ISI calibration between 0.109 and 0.105 M citrate, using 7 types of thromboplastin and various types of instrumentation. The two citrate concentrations were provided in both evacuated siliconised glass tubes and in evacuated polyethylene terephtalate (PET) tubes. The ISI difference between the two citrate concentrations was 5.4% for one system but not greater than 3% for all other systems when blood samples were collected with either siliconized glass or PET tubes. Most of the ISI differences between the two citrate concentrations were not significant at the 5% level. It is concluded that the ISI differences between 0.105 M and 0.109 M citrate are not of practical importance. In contrast, ISI differences between siliconised glass and PET tubes, using either 0.105 or 0.109 M citrate, were significant (p <0.05) for most thromboplastin systems and amounted to 7%. ISI interchange between these glass and PET tubes could induce INR differences amounting to 14%, which could affect clinical dosage of oral anticoagulants.
Platelet and Platelet-derived Microparticle Surface Factor V/Va Binding in Whole Blood: Differences between Neonates and Adults
Authors: Rajasekhar Damodara , Bednarek Francis , Barnard Marc , Michelson Alan
Published: March 2018

Platelet-derived microparticles (PDMP) appear to play a major role in the generation of procoagulant activity. In this study, we describe a novel flow cytometric method that allows direct evaluation of the procoagulant activity of PDMP and platelets in the physiological milieu of whole blood. The percent PDMP generated in response to calcium ionophore A23187 and calcium was increased in preterm neonates (67.5 ± 3.4%, mean ± S. E. M., n = 8, p <0.05) and term neonates (67.2 ± 2.7%, n = 7, p<0.05) compared with adults (49.5 ± 3.4%, n = 13). However, in preterm neonates A23187/calcium-induced binding of factor V/Va to PDMP and platelets (22.8 ± 5.6 fluorescence units) was markedly reduced (p <0.05) compared to term neonates (58.2 ± 7.2) and adults (50.6 ± 6.3). In preterm blood, A23187/calciuminduced binding of factor V/Va to PDMP and platelets returned to adult levels when: a) adult plasma, rather than autologous preterm neonatal plasma, was added; or b) factor V, but not factor VIII, was added to autologous preterm neonatal plasma. In summary: 1) We have developed a flow cytometric method for the direct detection of procoagulant PDMP and platelets in whole blood. 2) Compared to adults and term neonates, PDMP and platelets of preterm neonates bound markedly less factor V/Va (reflecting reduced procoagulant activity), because of a relative lack of factor V in preterm neonates. 3) This procoagulant defect in PDMP and platelets may contribute to the propensity of preterm neonates, but not term neonates, to intraventricular hemorrhage. 4) The percent PDMP does not necessarily reflect the degree of procoagulant activity of PDMP or platelets.
In Vivo Stimulation of Vascular Plasminogen Activator Inhibitor-1 Production by very Low-Density Lipoprotein Involves Transcription Factor Binding to a VLDL-Responsive Element
Authors: Ares Mikko , Stollenwerk Maria , Giachelli Cecilia , Scatena Marta , Hamsten Anders , Eriksson Per , Nilsson Jan , Dichtl Wolfgang
Published: March 2018

High plasma levels of plasminogen activator inhibitor-1 (PAI-1) are associated with an increased risk of cardiovascular disease. There is also a close relation between high plasma levels of PAI-1 and hypertriglyceridemia. Cell culture studies have shown that very low density lipoprotein (VLDL) increases the production and secretion of PAI-1 in endothelial cells and hepatocytes, suggesting a possible mechanism for this association. To determine whether VLDL stimulates PAI-1 production in vascular cells also in vivo, Sprague-Dawley rats were injected intravenously with 6 mg/kg of VLDL (derived from human subjects with type IV hyperlipidemia). Previous studies have demonstrated that this results in an accumulation of human VLDL in the aorta and other arteries followed by increased nuclear factor-kappa B (NF-κB) activation. Endothelial, but not smooth muscle cells, showed a basal PAI-1 mRNA and protein expression as assessed by in situ hybridization and immunohistochemistry, respectively. Six to twenty-four hours after the VLDL injection, lipoprotein particle accumulation was seen in the aortic wall, which was accompanied by increasing PAI-1 mRNA and protein expression in endothelial and smooth muscle cells. Within the rat PAI-1 promoter we identified a sequence located at −589 to −571 with 74% homology with the recently described VLDL responsive element in the human PAI-1 promoter and located adjacent to a 4-guanosine motif presumably corresponding to the human 4G/5G polymorphism. Transient transfection studies showed that VLDL exerts its stimulatory effects on rat PAI-1 gene expression in vascular cells by interaction with promoter sequences located within bp −656 and −505. Electrophoretic mobility shift assays showed that VLDL increases the binding of as yet incompletely characterized factors to this response element. Taken together these observations support a direct influence of VLDL on vascular PAI-1 gene expression in vivo. This stimulation is exerted on the level of PAI-1 gene transcription, and involves transcription factor binding to a VLDL responsive element adjacent to a 4G motif within the PAI-1 promoter.
Evaluation of D-dimer ELISA Test in Elderly Patients with Suspected Pulmonary Embolism
Authors: Tardy-Poncet Brigitte , Viallon Alain , Lafond Pierre , Page Y. , Venet Christophe , Bertrand Jean , Tardy Bernard
Published: March 2018

Study Objective: To determine the clinical usefulness of D-dimer ELISA test in elderly patients with clinically suspected pulmonary embolism (PE). Design: Prospective cohort study. Patients: Ninety-six consecutive outpatients older than 70 years with a duration of symptoms shorter than one week and without metastatic cancer or recent surgery, trauma, infection, stroke, myocardial infarction, deep vein thrombosis (DVT) or PE, or treatment with curative doses of heparin or oral anticoagulant. Intervention: All patients underwent at least ventilation/perfusion scan and bilateral ultrasonic duplex scan and a blood sample collection within 24 hours of admission. When necessary a pulmonary angiography and/or a bilateral venography were also performed. Patients were classified as follows: (1) PE-positive; positive angiography or high probability V/Q scan and deep vein thrombosis (proven either by venography or by ultrasonic duplex scan) or non high probability V/Q scan and either DVT (proven at presentation by venography or by ultrasonic duplex scan) or symptomatic thromboembolic event within 3 months of follow-up; or (2) PE-negative; normal V/Q scan or normal angiography or non high probability V/Q scan and either negative ultrasonic duplex scan or normal venography and low clinical probability and absence of symptomatic thromboembolism within 3 months of follow-up. D-dimer measurements were performed using both a conventional and a single semi-quantitative ELISA test (Asserachrom D-di, Instant I.A.D-dimer). Results: Using a cutoff value of 500 ng/ml, the conventional ELISA D-dimer test showed a sensitivity and a negative predictive value of 100% with poor specificity and positive predictive value of 14.3% and 45.5% respectively. The new rapid semi-quantitative D-dimer test displays worse results with sensitivity, negative predictive value, specificity and positive predictive value of 92.3%, 82.4%, 25% and 46% respectively. Conclusion: In a geriatric population, conventional ELISA D-dimer is a good marker to exclude PE but, due to the comorbid conditions, only a few patients presented with D-dimer values less than 500 ng/ml.
Anti-β2 Glycoprotein I Antibodies and Platelet Activation in Patients with Antiphospholipid Antibodies: Association with Increased Excretion of Platelet-Derived Thromboxane Urinary Metabolites
Authors: Forastiero Ricardo , Martinuzzo Marta , Maclouf Jacques , Carreras Luis
Published: March 2018

Platelet activation may contribute to the increased risk of thrombotic complications in patients with antiphospholipid antibodies (aPL). The increased urinary excretion of 11-dehydro-thromboxane B2 (11-DH-TXB2) reported in patients with lupus anticoagulant (LA) and/or anticardiolipin antibodies (aCL) reflects in vivo platelet activation. However the majority of autoimmune aPL are directed to β2 glycoprotein I (β2GPI) or prothrombin (II). We investigated the relationship of these antibodies with 11-DH-TXB2 urinary excretion in 34 patients with aPL. The urinary 11-DH-TXB2 was measured by EIA after extraction on octadecyl columns and purification on silica gel columns, which was validated by thin-layer chromatography/EIA procedure. A significantly increased excretion of 11-DH-TXB2 was found in aPL patients as compared to 18 normal controls (p <0.01). But no differences were seen in the excretion of 11-DH-TXB2 between patients with or without LA, or aCL. The number of patients with anti-II antibodies was too small to draw any conclusion. In contrast, patients with anti-β2GPI antibodies IgG at moderate/high titre (group A, n = 14) had higher levels of urinary 11-DH-TXB2 than those at low titre or negative (group B, n = 20) (p = 0.01). The group A of patients presented an increase in 11-DH-TXB2 compared to controls (p <0.001), but no statistically significant difference was found between patients from the group B and normal controls. A correlation between levels of urinary 11-DH-TXB2 and titre of antibodies was only found for anti-β2GPI-IgG (rs = 0.51, p <0.005). Our data show that the observed platelet activation in aPL patients is related to the presence of antibodies reacting with β2GPI.
Clot Accumulation Characteristics of Plasminogen-bearing Liposomes in a Flow-system
Authors: Feitsma H. , Kluft C. , Heeremans J. L. M. , Prevost R. , Crommelin D. J. A.
Published: March 2018

In this study, the clot accumulation properties of liposome-coupled plasminogen were compared to those of free (non-liposomal) plasminogen in an in vitro, closed-loop, flow-system. After introduction of a clot into the closed system, double-radiolabelled plasminogen-liposomes were administered and the accumulation of radiolabel on the entire clot was measured.

Liposomal plasminogen showed improved accumulation over free plasminogen, on both a fibrin clot and a whole blood clot. Moreover, once liposomal plasminogen was fibrin associated, it could not be washed away with buffer, in contrast to free plasminogen. Liposomal plasminogen was able to compete successfully with an excess of free plasminogen. The plateau levels for the accumulated amount of plasminogen depended on the incubated amount of plasminogen and were influenced by partial degradation of the clot. Furthermore, it was shown that a threshold liposomal plasminogen surface-density was needed for optimum clot accumulation.
Presence of Two Plasminogen Alleles in Normal Populations
Authors: Kida Masafumi , Kawabata Masuyo H.- , Yamazaki Tomio , Ichinose Akitada
Published: March 2018

When we compared nucleotide sequences of the 5’-flanking regions for plasminogen genes from 11 individuals, six substitutions were identified even among normal subjects. A new haplotype (termed allele II) was screened by PCR-RFLP analysis among 54 Japanese and 58 Caucasian normal subjects. The frequency of allele II was 0.787 in the Japanese and 0.560 in the Caucasians, indicating that the ratio of alleles differs between populations. Examination of 118 cases with dysplasminogenemia revealed that the Ala601-Thr mutation was present on allele I in most cases. This mutation was also associated with allele II in one-fourth of all cases, suggesting possible recombination within the plasminogen gene. Interestingly, we previously demonstrated that the expression activity of allele II was about 1.8 fold that of allele I in vitro.
Thrombopoietin Activates Human Platelets and Induces Tyrosine Phosphorylation of p80/85 Cortactin
Authors: Huret Guillaume , Loza Jean-Pierre , Adda Raphaël , Melle Josiane , Maclouf Jacques , Dreyfus François , Lévy-Toledano Sylviane , Fontenay-Roupie Michaëla
Published: March 2018

The mechanism of human platelet activation by thrombopoietin (TPO) was investigated in vitro. We found that rHuTPO stimulated thromboxane A2 formation and serotonin secretion, despite the absence of shape change and aggregation. Blockade of the arachidonic acid pathway did not inhibit rHuTPO-induced platelet secretion. rHuTPO stimulated the tyrosine phosphorylation of 64, 80/85, 95, 130 and 140 kDa proteins, but phosphoproteins of 100-105 and 125 kDa obtained when platelets aggregated in the presence of thrombin were absent. rHuTPO stimulated and potentiated the thrombin-induced tyrosine phosphorylation of a 80 kDa protein identified as the cortical actin-associated protein, p80/85 cortactin. When platelets were aggregated in the presence of rHuTPO and fibrinogen, cortactin phosphorylation was enhanced as compared to rHuTPO alone. Treatment with RGDS or cytochalasin D respectively reduced or abolished cortactin tyrosine phosphorylation. This confirms the existence of fibrinogen binding-dependent and independent pools of phosphorylated cortactin, both requiring intact actin polymerization. Cytoskeleton-binding proteins may be implicated in in vitro platelet activation by rHuTPO.