bluuebunny/crossref_metadata_2025_split huggingface dataset:
Early Identification and Prognostic Implications in Disseminated Intravascular Coagulation through Transmittance Waveform Analysis
Authors: Downey Colin , Kazmi Rashid , Toh Cheng Hock 
Published: March 2018

SummaryEfforts to improve the prognosis in disseminated intravascular coagulation (DIC) have been hampered by the lack of an early, useful and rapidly available diagnostic marker. More recently, a characteristic bi-phasic change in the light transmittance waveform profile of the APTT assay has been associated with DIC. In this prospective study, we have assessed the utility of this assay in the routine clinical setting. 1,470 samples were analysed from 747 patients and 41 patients had DIC. The sensitivity and specificity of the bi-phasic waveform pattern for DIC was 97.6% and 98% respectively. The appearance of a biphasic waveform preceded the development of abnormalities in the standard laboratory tests for DIC and waveform changes correlated closely with clinical events. In conclusion, transmittance waveform analysis is not only useful as an early diagnostic and single monitoring marker of DIC but the quantifiable and standardisable changes also allow for prognostic applicability in clinical management.
Use of a Heparin Nomogram for Treatment of Patients with Venous Thromboembolism in a Community Hospital
Authors: Büller Harry , ten Cate Jan , Kooy Marinus van Marwijk , de Groot Marco 
Published: March 2018

SummaryBackground: The application of a heparin dosing nomogram in the treatment of patients with venous thromboembolism resulted in improvement of heparin therapy in clinical research settings. In 1992 a heparin nomogram was introduced in our hospital, which is a community hospital where anticoagulant therapy is supervised by the attending physicians. We studied whether comparable improvements were achieved in such a non-surveyed clinical setting. Methods: Patients were identified from computerized discharge records, and classified into a pre-nomogram (discharged in 1990 or 1991) and a nomogram patient group (discharged in 1993 or 1994). The use of the nomogram was encouraged but the application remained on a voluntary basis. Since the definition of the target APTT range was different in the pre-nomogram period as compared to the nomogram period, a formal analysis of pre- and post-nomogram results was not considered justified. Results: The APTT ratio, six hours after the start of heparin treatment, was below the predefined lower limit in 72% of 127 patients in the pre-nomogram group and in 13% of 127 patients in the nomogram group. During 1043 days heparin therapy in the nomogram group the morning APTT ratio was subtherapeutic in 8%. In 58% of all APTT results the physician responded according to the nomogram. The subsequent APTT was in the target range in 64% of the cases compared to 31% if the adjustement was not performed according to the nomogram (P<.0001). Major bleeding episodes occurred in 3.1% in the pre-nomo-gram period and in 0.7% in the nomogram period.Conclusion: The present study shows that the introduction of a heparin dosing nomogram in a non-research clinical setting results in more adequate heparin anticoagulation with low risks of bleeding.
Influence of Low Molecular Weight Heparin and Low Molecular Weight Dextran Sulfate on the Inhibition of Coagulation Factor XIa by Serpins
Authors: Mauron Thomas , Lämmle Bernhard , Wuillemin Walter 
Published: March 2018

SummaryWe investigated the influence of low molecular weight dextran sulfate (LMWdxs) and low molecular weight heparins (LMWH: dalteparin, enoxaparin and nadroparin) on the inhibition of FXIa by C1-inhibitor, α1-antitrypsin, α2-antiplasmin and antithrombin in a purified system and in plasma.The second order rate constant for inactivation of FXIa by C1-inhibitor, α1-antitrypsin, α2-antiplasmin, and antithrombin was 1.23, 0.056, 0.33 and 0.59 × 103 M–1 s–1, respectively.LMWdxs and LMWH dose-dependently increased the second order rate constant of the inactivation of FXIa by C1-inhibitor up to 39-fold. The second order rate constant of the inactivation of FXIa by anti-thrombin was increased up to 6-fold by LMWH, whereas LMWdxs had no effect. In plasma, FXIa was inactivated to about 50% by C1-inhibitor, while the other serpins contributed together to the remaining 50% of plasma’s inhibitory capacity towards FXIa. In the presence of LMWdxs or LMWH, FXIa was inactivated in plasma to more than 90% by C1-inhibitor. LMWH at maximal therapeutic plasma levels enhanced the contribution of antithrombin to the inactivation of FXIa in plasma up to 5-fold.In conclusion, we found that the tested low molecular weight glycosaminoglycans dalteparin, enoxaparin and nadroparin and LMWdxs stimulate inactivation of FXIa by C1-inhibitor in a system using purified proteins as well as in plasma. Furthermore, LMWH but not LMWdxs slightly enhanced FXIa inhibition by antithrombin.
Control of Oral Anticoagulation in Patients with the Antiphospholipid Syndrome – Influence of the Lupus Anticoagulant on International Normalized Ratio
Authors: Querrec Le , Delahousse B. , Caron C. , Houbouyan L. , Boutière B. , Horellou M.H. , Reber G. , Sié P. , Robert A. ,   the Groupe «Méthodologie en Hémostase» du Groupe d’Etudes sur l’Hémostase et la Thrombose
Published: March 2018

SummaryThe recommended therapeutic range of International Normalized Ratio (INR) for oral anticoagulant treatment in patients with the antiphospholipid syndrome remains controversial. As a part of this controversy, it has been suggested that lupus anticoagulants (LA) could interfere with the determination of prothrombin time, thus questioning the validity of monitoring the treatment of these patients using INR. To clarify this point, we compared the values of INR obtained in the plasmas of two groups of patients, one without LA (n = 47), and the other with LA (n = 43). INR were determined using 8 different thromboplastin reagents on the same automated coagulation instrument. Chromogenic factor X, which is supposed to be insensitive to the presence of LA, was also measured. The results are the following: provided INR was calculated using calibrated reference plasmas, there was no significant difference between INR values obtained with the 8 reagents, both in the non-LA and in the LA groups (CV: 5.9 and 6.7%, respectively). Closer examination revealed that INR results obtained with one reagent (the recombinant thromboplastin Innovin) diverged from those of the 7 others, leading to an overestimation of INR, to a very large extent in some instances. However this effect was restricted to a subset of the patient population with LA (6 out of 43). Finally, the relationship between INR (average value obtained using the 8 reagents) and factor X was identical in non-LA and in LA patient groups. We conclude that, provided the reagents which display the LA interference are identified and excluded for this purpose, the INR system is valid for monitoring oral anticoagulant treatment in patients with LA.
Human Thrombin and Calcium Bound Factor Xa Significantly Shorten tPA-Induced Fibrin Clot Lysis Time via Neutralization of Plasminogen Activator Inhibitor Type 1 Activity
Authors: Urano Tetsumei , Nagai Nobuo , Matsuura Megumi , Ihara Hayato , Takada Yumiko , Takada Akikazu 
Published: March 2018

SummaryEmploying a fibrin clot lysis assay, we reassessed the significance of the neutralization of plasminogen activator inhibitor type 1 (PAI-1) activity by thrombin and factor-Xa in fibrinolysis. When PAI-1 enriched fibrin clots were formed using increasing concentrations of thrombin (0.1, 0.5, 1.0 IU/ml), their lysis times became shorter (43.8 ± 4.9, 25.7 ± 3.7, 13.9 ± 0.8 h respectively). Times were shortened further by either heparin (43.9 ± 11.0, 12.1 ± 2.6, 3.6 ± 0.2 h respectively) or vitronectin (17.0 ± 1.6, 1.9 ± 0.7, 0.9 ± 0.0 h respectively). Factor-Xa together with Ca++ shortened the clot lysis time further. Fibrin autography revealed that both enzymes dose dependently interfered with complex formation between tPA and PAI-1, making large amounts of tPA remaining to be free form. The mechanism seems to play a role in the coagulation associated enhancement of fibrinolysis.
Peripheral Blood Platelets Express VEGF-C and VEGF which Are Released during Platelet Activation
Authors: Wartiovaara Ulla , Salven Petri , Mikkola Hanna , Lassila Riitta , Kaukonen Jaakko , Joukov Vladimir , Orpana Arto , Ristimäki Ari , Heikinheimo Markku , Joensuu Heikki , Alitalo Kari , Palotie Aarno 
Published: March 2018

SummaryVEGF-C is a recently characterised endothelial growth factor structurally related to vascular endothelial growth factor (VEGF). We studied the expression of VEGF-C and VEGF in the cells of peripheral blood and in the umbilical cord blood CD 34+ cells, representing haematopoietic progenitor cells. Expression of VEGF-C was detected in the CD34+ cells. In peripheral blood VEGF-C mRNA was restricted to platelets and T-cells. In contrast to the expression pattern of VEGF-C, VEGF mRNA was detected in all peripheral blood cell fractions studied, and also in CD34+ cells. VEGF-C mRNA was also detected in fresh bone marrow samples of acute leukaemia patients, but the expression did not show lineage specificity. VEGF-C and VEGF polypeptides were present in platelets and they were released from activated platelets together with the release of β-thromboglobulin, suggesting that VEGF-C and VEGF reside in the α-granules of platelets. VEGF-C and VEGF, released from activated platelets, may have a role in angiogenesis during wound healing, and possibly also in other pathological conditions, such as atherosclerosis, tumour growth, and metastasis formation.
Effective Use of BCH-2763, a New Potent Injectable Direct Thrombin Inhibitor, in Combination with Tissue Plasminogen Activator (tPA) in a Rat Arterial Thrombolysis Model
Authors: Deschênes Isabelle , Finkle Carolyn , Winocour Peter 
Published: March 2018

SummaryCurrent therapeutic use of heparin as an adjunct to thrombolytic therapy for myocardial infarction is suboptimal with respect to efficacy and bleeding risk. In a rat carotid arterial thrombolysis model (FeCl3-induced injury) we evaluated the combined effect of tPA (2.0 mg/kg/ 30 min) with our potent injectable direct thrombin inhibitor, BCH-2763 (Ki 0.11 nM; MW 1.5 kDa), which, unlike heparin, inhibits bound and free thrombin; comparisons were with standard heparin (SH), other direct thrombin inhibitors, r-hirudin (MW 6.5 kDa) and hirulog (MW 2.3 kDa), or tPA alone. Time to lysis (TL), patency time (PT), aPTT (fold increase) and bleeding time (BT) were determined. ED100 (100% of rats reperfused) for BCH-2763, hirulog or r-hirudin was 1, 3 or 2 mg/kg/60 min, respectively; 67% of rats reperfused with SH at the highest dose tested (220 U/kg/60 min) and 43% with tPA alone. At these doses, TL (min) was shorter (p <0.01) with BCH-2763 (0.5 ± 0.1), hirulog (3.3 ± 2.3) or r-hirudin (2.3 ± 1.0) than SH (66.3 ± 30.8) or tPA alone (93.4 ± 21.4). The aPTT fold increase after 15 min infusion was markedly greater (p <0.001) for SH (32.0 ± 0.8) than BCH-2763 (3.7 ± 0.5), hirulog (5.2 ± 0.3) or r-hirudin (4.5 ± 0.8) in combination with tPA or tPA alone (1.1 ± 0.1). In addition, the BT (min) for BCH-2763 (3.0 ± 0.4) was similar to tPA alone (1.6 ± 0.3), but prolonged (p <0.05) for hirulog (7.5 ± 2.7), r-hirudin (6.6 ± 0.8) or SH (7.3 ± 1.8). Comparisons at same aPTT fold increase revealed that in combination with tPA, BCH-2763 required a lower anticoagulant level to shorten the TL and prolong the PT than hirulog, r-hirudin or SH. Thus, in this rat arterial thrombolysis model direct thrombin inhibitors are more effective than SH as antithrombotic adjuncts to tPA. BCH-2763 is effective at a lower gravimetric dose and more modest aPTT fold increase than hirulog or r-hirudin with less alteration in haemostasis, which may confer an improved safety index.
Effects of Recombinant Human Soluble Thrombomodulin (rhs-TM) on Clot-induced Coagulation in Human Plasma
Authors: Suzuki Makoto , Sugimoto Emika , Sata Minako , Yamamoto Syuji , Maruyama Ikuro , Mohri Mitsunobu 
Published: March 2018

SummaryRecent studies have suggested that clot-bound thrombin plays an important role in thrombus growth. In this study, we examined the effects of recombinant human soluble thrombomodulin (rhsTM) on clot-induced coagulation. rhsTM enhanced the activation of protein C by clots, and attenuated clot-induced thrombin generation and fibrinopep-tide A (FPA) production in a dose-dependent manner. The inhibitory effect of rhsTM was abolished by anti-protein C antibody. The inhibitory effect of rhsTM on clot-induced thrombin generation continued for over 60 min after the addition of the clot, while an active site-directed thrombin inhibitor, argatroban, produced a more transient inhibition. rhsTM also inhibited the regrowth of the clot in 125I-fibrinogen-supplemented plasma. We also examined the effect of rhsTM by thromboelastography; rhsTM reduced the growth of the clot but had little effect on the time to begin clotting, while heparin and Fragmin (low molecular weight heparin) had effects opposite to those of rhsTM.These findings suggest that rhs-TM attenuates the growth of the clot by activating protein C and inhibiting further thrombin generation in the clot.
A Plasma Coagulation Assay for an Activated Protein C-independent Anticoagulant Activity of Protein S
Authors: van ’t Veer Cornelis , Meijers Joost , Bertina Rogier , Wijnen Merel van , Bouma Bonno 
Published: March 2018

SummaryTo study the physiological importance of the activated protein C (APC)-independent anticoagulant activity of protein S, we developed an assay specific for this activity. The ability of protein S to prolong the clotting time in an APC-independent way was expressed as the ratio of the clotting time in a plasma sample divided by the clotting time in the presence of a polyclonal antibody against human protein S (both after 1:1 dilution in protein S-C4BP deficient plasma). The mean protein S-dependent anticoagulant ratio (PSdAR) was 1.53 ± 0.18 in 34 healthy controls, and was significantly lower in 16 heterozygous protein S deficient patients (PSdAR = 1.15 ± 0.09). In plasmas from patients under oral anticoagulant therapy the mean PSdAR was within the range of the control population (1.50 ± 0.18). The mean total protein S antigen level in these plasmas was 58%, suggesting a higher specific APC-independent anticoagulant activity of protein S in these patients than in normals.This functional protein S assay can be used for the laboratory diagnosis of protein S deficiency, and to study the mechanism of the APC-independent anticoagulant activity in plasma.
Identification and Characterization of Two Thrombin-activatable Fibrinolysis Inhibitor Isoforms
Authors: Morser John , Bajzar Laszlo , Nesheim Michael , Nagashima Mariko , Zhao Lei 
Published: March 2018

SummaryThrombin-activatable fibrinolysis inhibitor (TAFI) is synthesized by the liver and is thought to circulate in plasma as a plasminogen-bound zymogen. When it is activated by the thrombin/thrombomodulin complex, activated TAFI exhibits carboxypeptidase B-like activity. To study the structure-function relationship of TAFI, we expressed recombinant human TAFI in insect cells. During the cloning of TAFI cDNA from several human liver cDNA libraries, we identified a second TAFI cDNA which differed from the published sequence at 2 positions. One of these sequences resulted in a substitution of alanine for threonine at residue 147, the other was a silent mutation. These substitutions were found in several cDNA libraries from different sources. Using Southern blot analysis, we confirmed the existence of this TAFI polymorphism in the population. In order to compare the activation and activity of TAFI isoforms, we expressed both isoforms in the baculovirus expression system, and compared the enzyme kinetics of the purified proteins. The molecular weight of recombinant TAFI is lower than plasma TAFI due to differences in glycosylation. The two recombinant TAFI iso-forms had similar activation kinetics and the activated enzymes had similar carboxypeptidase B-like activity towards small molecule substrates. Their ability to retard clot lysis was found to be similar in a plate clot lysis assay.
4G/5G Polymorphism of PAI-1 Gene Promoter and Fibrinolytic Capacity in Patients with Deep Vein Thrombosis
Authors: Sartori Maria Teresa , Wiman Björn , Vettore Silvia , Dazzi Francesco , Girolami Antonio , Patrassi Giovanni Maurizio 
Published: March 2018

SummaryA deletion/insertion polymorphism (4G or 5G) in the promoter of the plasminogen activator inhibitor type 1 gene has been suggested to be involved in regulation of the synthesis of the inhibitor, the 4G allele being associated with enhanced gene expression. A relationship between 4G/5G polymorphism and PAI-1 levels was found in patients with cardiovascular and metabolic diseases, but not in healthy subjects. In the present work we studied the distribution of PAI-1 4G/5G geno-type and its relation to fibrinolytic capacity in 70 unrelated patients with deep vein thrombosis. Each patient was assayed before and after 20 min. Venous occlusion for euglobulin lysis time, t-PA antigen and activity, and PAI-1 antigen and activity. The prevalence of 5G homozygous carriers was significantly lower in patients than in controls (10% vs. 26%, p = 0.009). The 5G allele frequency was reduced, even though not significantly, in DVT patients compared to healthy subjects (0.40 vs. 0.51, respectively). In the patient group, the mean PAI-1 antigen and activity levels were significantly higher than among controls and related to the 4G/5G polymorphism. In patients with 4G/5G and 4G/4G genotype a significant correlation was found between PAI-1 levels and the global fibrinolytic activity as evaluated by euglobulin lysis time. The prevalence of a reduced fibrinolytic potential due to PAI-1 excess was 45.7% among DVT patients. Moreover, the prevalence of PAI-1 induced hypofibrinolysis was strongly related to PAI-1 polymorphism, since it was significantly lower in 5G homo-zygous patients (28.6%) than in both 4G/5G carriers (55.3%, p <0.001) and 4G homozygous patients (57.9%, p <0.001).In conclusion, in patients with deep vein thrombosis the 4G polymorphism of PAI-1 gene promoter may influence the expression of PAI-1 and it should be taken into consideration as a facilitating condition for pathological fibrinolysis together with other environmental and genetic factors. Whether this has any significance in regard to the pathogenesis of venous thrombosis remains to be proven.
The Effects of MPL-Ligand, Interleukin-6 and Interleukin-11 on Megakaryocyte and Platelet Alpha-granule Proteins
Authors: Remmler Jill , Zucker-Franklin Dorothea , Philipp Claire 
Published: March 2018

SummaryThrombopoietin (Mpl ligand), interleukin-6 (IL-6), and interleukin-11 (IL-11) differ in their effects on megakaryocyte maturation and development. In the present study, the impact of these thrombocytopoietic cytokines on biochemical and structural granule and membrane components was examined. Western blotting was performed on equivalent amounts of isolated megakaryocyte or platelet protein and the relative intensities of the enhanced chemiluminescent-visualized bands were quantitated by densitometry. Megakaryocyte growth and development factor (MGDF), a recombinant thrombopoietin-related molecule, significantly increased megakaryocyte fibronectin (72%), thrombospondin (55%), von Willebrand factor (28%) and p-selectin (CD62p) (37%) when compared to equivalent amounts of protein from saline-treated controls (p < 0.01). Megakaryocyte fibrinogen was not increased. Ultrastructurally, there was a marked increase in ribosomes and rough endoplasmic reticulum even in mature-appearing megakaryocytes. Platelets from MGDF-treated mice showed small increases in fibronectin (8%), and CD62p (18%), but did not show increases in other measured α-granule proteins. Neither IL-6 nor IL-11 increased megakaryocyte or platelet α-granule proteins over levels observed in saline controls. IL-11 treated megakaryocytes, while also exhibiting an increase in ribosomes, were characterized by prominent cytoplasmic fragmentation. The study demonstrates the impact of Mpl ligand in increasing synthesized megakaryocyte α-granule proteins and of IL-11 in promoting megakaryocyte fragmentation.
Melagatran, a Low Molecular Weight Thrombin Inhibitor, Counteracts Endotoxin-induced Haemodynamic and Renal Dysfunctions in the Pig
Authors: Larsson Anders , Saldeen Tom , Mattsson Christer , Eriksson Mats 
Published: March 2018

SummaryCoagulation and fibrinolysis are crucial in septic shock and inhibition of thrombin may be beneficial in this circumstance. Since porcine endotoxaemia has been found to replicate severe septic shock, a low molecular weight thrombin inhibitor, melagatran, was infused during the first 3 out of 6 h of endotoxaemia in pigs. Plasma creatinine (p <0.01) and urinary output (p <0.05) were less affected in the melagatran + endotoxin group (n = 6) as compared to endotoxaemic controls (n = 9). The left ventricular stroke work index, systemic vascular resistance index and oxygen extraction were all less affected (p <0.05) by endotoxin during the infusion of melagatran. The plasma concentration of melagatran declined with an apparent plasma half-life of 5 h as soon as the infusion was stopped. APTT, however, continued to increase after the infusion of melagatran had stopped and reached a maximum of 113 s at 5 h (baseline 17 s). APTT in endotoxaemic control pigs reached a maximum of 22 s. Thus, melagatran may counteract some consequences of endotoxaemia.
Modeling Human Zymogen Factor IX
Authors: Perera Lalith , Darden Thomas , Pedersen Lee 
Published: March 2018

SummaryModern theoretical techniques are employed to provide complete three dimensional structure for the zymogen and activated forms of human coagulation factors IX and IXa. These structures are fully calcium bound and equilibrated in an electrically neutral aqueous environment. The relationship of structure to mutational data is examined. We find that a substantial relative orientational change of the catalytic domain occurs on activation. Also, we find that the electrostatistically dipolar nature of the catalytic domain is substantially modified upon activation, with cleavage of the negatively charged activation peptide leaving behind a largely hydrophobic face in factor IXa. While the backbone atoms of the catalytic residues have little relative movement, nearby loops are found that do move. The presence or absence of these changes likely defines specificity.