bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hemoglobin Enhances the Binding of Bacterial Endotoxin to Human Endothelial Cells
Authors: Roth Robert I 
Published: July 2018

SummaryHuman endothelial cells, when incubated with bacterial endotoxin (lipopolysaccharide, LPS), modify their surface in association with prominent production of procoagulant tissue factor (TF) activity. This deleterious biological effect of LPS has been shown previously to be enhanced approximately 10-fold by the presence of hemoglobin (Hb), a recently recognized LPS binding protein that causes disaggregation of LPS and increases the biological activity of LPS in a number of in vitro assays. The present study was performed to test the hypothesis that Hb enhances the LPS-induced procoagulant activity of human umbilical vein endothelial cells (HUVEC) by increasing LPS binding to the cells. The binding of 3H-LPS to HUVEC was determined in the absence or presence of Hb or two other known LPS-binding proteins, human serum albumin (HSA) and IgG. LPS binding was substantially increased in the presence of Hb, in a Hb concentration-dependent manner, but was not increased by HSA or IgG. Hb enhancement of LPS binding was observed in serum-free medium, indicating that there was no additional requirement for any of the serum factors known to participate in the interaction of LPS with cells (e.g., lipopolysaccharide (LPS)-binding protein (LBP) and soluble CD14 (sCD14)). Hb enhancement of LPS binding also was observed in the more physiologic condition of 100% plasma. LPS-induced TF activity was stimulated by Hb, but not by HSA or IgG. In serum-free medium, TF activity was not stimulated under any of the conditions tested. Ultrafiltration of LPS was dramatically increased after incubation with Hb but not with HSA or IgG, suggesting that LPS disaggregation by Hb was responsible for the enhanced binding of LPS to HUVEC and the subsequent stimulation of TF activity.
Postprandial Activation of Coagulant Factor VII by Long-chain Dietary Fatty Acids
Authors: Sanders T A B , Miller G J , de Grassi Tamara , Yahia Najat 
Published: July 2018

SummaryFactor VII coagulant activity (FVIIc) is associated with an increased risk of fatal ischaemic heart disease (IHD). Several reports have suggested that dietary fat intake or hypertriglyceridaemia are associated with elevated levels of FVII. This study demonstrates that an intake of long-chain fatty acids sufficient to induce postprandial lipaemia in healthy subjects leads to a substantial elevation in both FVIIc and the concentration of FVII circulating in the activated form. Such an increase in FVIIc could not be induced by medium-chain triglycerides. These results suggest that the consumption of a sufficient amount of long-chain triglycerides to induce postprandial lipaemia induces the activation of FVII.
Normal Binding of Calcium to Five Fibrinogen Variants with Mutations in the Carboxy Terminal Part of the γ-Chain
Authors: Furlan Miha , Stucki Bettina , Steinmann Colette , Jungo Myriam , Lämmle Bernhard 
Published: July 2018

SummaryCalcium ions are known to accelerate polymerization of fibrin monomers. Each of the two carboxy terminal domains of normal fibrinogen contains one high-affinity calcium binding site that seems to be situated close to the polymerization site in the γ-chain. Most hitherto described functionally defective fibrinogen variants showed impaired clot formation. Since the tightly bound calcium ions may influence the conformation of the polymerization site, the question arises whether the abnormal clotting of a dysfibrinogen might be due to defective calcium binding. We investigated binding of calcium to fibrinogen and the effect of calcium on the clotting properties of five heterozygous fibrinogen variants showing normal thrombin-induced fibrinopeptide release but abnormal polymerization of fibrin monomers. Each of these dysfibrinogens has one single amino acid substitution in the carboxy-terminal part of the γ-chain: fibrinogen Claro (γ 275 Arg ⟶ His), Milano V (γ 275 Arg Cys), Milano I (γ 330 Asp ⟶ Val), Bern I (γ 337 Asn Lys), and Milano VII (γ 358 Ser Cys). The shortest thrombin clotting time and the earliest onset of turbidity increase were observed in fibrinogen γ 358 Ser ⟶ Cys; both parameters were little affected by calcium concentration. In the variant γ 337 Asn ⟶ Lys, the thrombin time was abnormally prolonged at 0.01 mM Ca2+, but it was normalized at 1 mM calcium. In contrast, the abnormal fibrin polymerization of fibrinogen γ 330 Asp ⟶ Val was barely improved at increasing calcium concentrations. Both variants with the substitution of γ 275 Arg, the residue indispensable for normal D:D interactions, showed the slowest rate of fibrin polymerization and the lowest turbidity of fibrin clots at any Ca2+ concentration used. High affinity calcium binding was found to be normal in all five fibrinogen variants studied, suggesting that their abnormal clotting was not due to defective binding of calcium. The γ-chain in the fragment D1 derived from the variant γ 337 Asn ⟶ Lys was further degraded by plasmin in the presence and in the absence of calcium, whereas fragments D1 from the other four γ-chain variants as well as from normal fibrinogen were protected against plasmic degradation in the presence of 1 mM Ca2+.
Experimental Pharmacology of Hirunorm: a Novel Synthetic Peptide Thrombin Inhibitor
Authors: Cirillo Rocco , Lippi Annalisa , Subissi Alessandro , Agnelli Giancarlo , Criscuoli Marco 
Published: July 2018

SummaryEnhanced thrombin activity has been associated with coronary thrombosis and with acute and long-term complications following coronary balloon angioplasty. Blocking thrombin activity with specific inhibitors is proposed as a promising antithrombotic therapy. We describe the anticoagulant and antithrombotic properties of hirunorm, a novel synthetic 26-aminoacid peptide thrombin inhibitor, in comparison with r-hirudin and hirulog-1. Hirunorm was equipotent to hirulog-1 and 1/30 as potent as r-hirudin in blocking a-thrombin amidolytic activity (IC50 = 10 ± 2,15 ± 1 and 0.3 ± 0.1 nM, respectively), but it did not affect trypsin, plasmin and t-PA activities at 10 μM. All the compounds inhibited clot-bound thrombin to clots prepared by thrombin hydrolysis of purified fibrinogen in buffer. Hirunorm and hirulog-1 showed similar species-dependent potency in doubling basal in vitro clotting times of human, rat and rabbit plasma (EC200 varied 70 to 200 nM for TT, 0.7 to 16 μM for aPTT and 0.8 to 17 μM for PT), while r-hirudin was always at least three times more active. When assayed by HPLC or by bioassay of the intact peptide, hirunorm was stable against a-thrombin and plasma hydrolases, but it was catabolized by rat liver and kidney enzymes. Venous thrombosis was produced in anaesthetized rats by vena cava ligation following a procoagulant serum injection. Intravenous and subcutaneous hirunorm inhibited venous thrombosis at doses (≤0.3 mg/kg) two-three times higher than those of r-hirudin. Hirulog-1 was as active as hirunorm only after i. v. infusion. Arterial thrombosis was obtained in the anaesthetized rat by chemical (FeCl2) stimulation of a common carotid and i.v. infused hirunorm (1-3 mg/kg/30 min) inhibited it dose-dependently; r-hirudin was partly active only at 3 mg/kg, but hirulog-1 was inactive at either dose. Full antithrombotic doses of hirunorm did not affect the bleeding time as measured from punctured mesenteric vessels, in anaesthetized rats. In conclusion, hirunorm is a potent peptide thrombin inhibitor endowed with antithrombotic activity in models of venous and arterial thrombosis.
The Interaction of Protein S with the Phospholipid Surface Is Essential for the Activated Protein C-independent Activity of Protein S
Authors: Wijnen Merel van , Stam Jeanette G , van't Veer Cornells , Meijers Joost C M , Reitsma Pieter H , Bertina Rogier M , Bouma Bonno N 
Published: July 2018

SummaryProtein S is a vitamin-K dependent glycoprotein involved in the regulation of the anticoagulant activity of activated protein C (APC). Recent data showed a direct anticoagulant role of protein S independent of APC, as demonstrated by the inhibition of prothrombinase and tenase activity both in plasma and in purified systems. This anticoagulant effect of protein S can be explained either by a direct interaction of protein S with one of the components of the complexes and/or by the interference with the binding of these components to phospholipid surfaces.During our investigation we noted that protein S preparations purified in different ways and derived from different sources, expressed discrepant APC cofactor and direct anticoagulant activity. In order to elucidate these differences and to study the mechanism of the APC-inde-pendent activity of protein S, we compared the protein S preparations in phospholipid-binding properties and anticoagulant activity. The dissociation constant for the binding of protein S to immobilized phospholipids ranged from 7 to 74 nM for the different protein S preparations. APC-independent inhibition of both prothrombinase and tenase activity performed on phospholipid vesicles and in plasma showed a strong correlation with the affinity for phospholipids. The APC-independent activity could be abolished by monoclonal antibodies that were either calcium-dependent and/or directed against epitopes in the Gla-region of protein S, suggesting that the protein S-phospholipid interaction is crucial for the APC-independent anticoagulant function of protein S. Protein S preparations with a low APC-independent activity expressed a high APC-cofactor activity suggesting that the affinity of protein S for phospholipids is of less importance in the expression of APC-cofactor activity of protein S.We conclude that high affinity interactions of protein S with the membrane surface are essential for the direct anticoagulant activity of protein S and we suggest that inhibition of the prothrombinase and the tenase complex by protein S is a consequence of the occupation of the phospholipid surface by protein S molecules.
Haemostatic Parameters and Lifestyle Factors in Elderly Men in Italy and The Netherlands
Authors: Bijnen Fransje C H , Feskens Edith J M , Giampaoli Simona , Menotti Alessandro , Fidanza Flaminio , Hornstra Gerard , Caspersen Carl J , Mosterd Willem L , Kromhout Daan 
Published: July 2018

SummaryThe association between plasma fibrinogen, factor VII, factor X, activated partial thromboplastin time, antithrombin III and the lifestyle factors cigarette smoking, alcohol use, fat intake and physical activity was assessed in 802 men aged 70-90 years in Zutphen (The Netherlands), Montegiorgio and Crevalcore (Italy).Smoking was positively associated with fibrinogen, also after adjustment for other lifestyle factors, age, use of anticoagulants and aspirin like drugs, body mass index, and history of myocardial infarction. Alcohol use was associated with increased levels of factor X and decreased levels of antithrombin III. Fat intake was positively associated with antithrombin III. Between cohorts, considerable differences were observed in levels of haemostatic parameters and the lifestyle factors. Compared to the mediterranean cohorts the Zutphen cohort showed the highest levels of fibrinogen and factor VII. Differences in lifestyle factors could, however, not explain differences between cohorts in levels of any of the haemostatic parameters, despite the observed associations between lifestyle factors and haemostatic parameters.
Inhibitory Effect of Prostacyclin and Nitroprusside on Type IIB von Willebrand Factor-promoted Platelet Activation
Authors: Francesconi Mariangela , Casonato Alessandra , Pagan Stefano , Donella-Deana Arianna , Pontara Elena , Girolami Antonio , Deana Renzo 
Published: July 2018

SummaryVon Willebrand disease (vWD) of type IIB is a hereditary haemorragic disorder characterised by an excessive interaction of von Willebrand factor (vWF) with the platelet receptor GPIb which promotes platelet activation and aggregation through a phospholipase A2-mediated release of arachidonic acid.The present report shows that prostacyclin and nitroprusside, vaso-dilator-compounds that enhance the cAMP and cGMP concentration respectively, cause a drastic inhibition of the type IIB vWF-induced platelet responses including increase of cytosolic Ca2+ concentration, phosphorylation of pleckstrin (47 kDa) and myosin light chain (20 kDa), secretion of ATP and serotonin, and aggregation parallel to a decrease of arachidonic acid release. Type IIB vWF also elicits tyrosine phosphorylation of proteins with apparent molecular mass of 60,74,82 and 130 kDa. Prostacyclin, which induces per se tyrosine-phosphoryla-tion of proteins of about 38 and 45 kDa, inhibits drastically the type IIB vWF-promoted tyrosine-phosphorylation of the 74 kDa protein while inhibits slightly that of 60 kDa band. The protein tyrosine-kinase inhibitor genistein causes a little decrease in the type IIB vWF-induced release of arachidonic acid.It is concluded that the inhibition exerted by prostacyclin and nitroprusside on type IIB vWF-elicited platelet activation seems to be largely ascribable to prevention of the phospholipase A2 activation with the ensuing decrease of the subsequent protein tyrosine phosphorylation
Pre- and Postoperative State of Coagulation and Fibrinolysis in Plasma of Patients with Benign and Malignant Colorectal Disease - A Preliminary Study
Authors: Iversen L H , Okholm M , Thorlacius-Ussing O 
Published: July 2018

SummaryThis study was carried out in order to compare the coagulation balance in patients with colorectal cancer before and after surgical removal of tumor with an age matched non-malignancy control group. Furthermore, it was studied whether preoperative coagulation state in cancer patients was correlated to the postoperative development of deep venous thrombosis (DVT) diagnosed by venography. Plasma was collected preoperatively in 93 cancer patients and 30 controls, and postoperatively on day one, two, seven, and ninety in 88 cancer patients and 18 controls. Prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin complex (TAT), and total fibrin(ogen) degradation products (TDP) were quantitated in plasma by enzyme linked immunosorbent assays (ELISA). As compared to controls, patients admitted for cancer treatment displayed significantly higher levels of F1 + 2 and TAT. Patients suffering from advanced colorectal cancer had significantly higher levels of TAT and TDP as compared to patients with localized colorectal cancer. Twenty-three percent of cancer patients developed DVT postoperatively. Preoperatively these patients displayed significantly higher TDP levels, and postoperatively higher levels of F1 + 2, TAT, and TDP compared to cancer patients without DVT. The marked activation of blood coagulation and fibrinolysis observed in all patients following major abdominal surgery was even more pronounced in patients not cured for cancer.
Proneness to Formation of Tight and Rigid Fibrin Gel Structures in Men with Myocardial Infarction at a Young Age
Authors: Fatah Kamaran , Silveira Angela , Tornvall Per , Karpe Fredrik , Blombäck Margareta , Hamsten Anders 
Published: July 2018

SummaryThe native fibrin gel structure formed in vitro from plasma samples was examined by liquid permeation of hydrated fibrin gel networks in 38 unselected men who had suffered a myocardial infarction before the age of 45 years and in 88 age-matched population-based control men. Both the fibrin gel porosity (permeability coefficient, Ks) and the calculated fiber mass-length ratio varied considerably within the two groups, but were generally lower in the patients. Ks was 8.3 ± 5.2 cm2 × 109 (mean ± SD) in the patient group and 12.5 ± 5.7cm2 × 109 among controls (p <0.001). The corresponding figures for fiber mass-length ratio were 13.1 ± 7.7 and 16.5 ± 7.5 Dalton/ cm × 10−13, respectively (p <0.01). Around 50% of the patients had Ks values below the 10th percentile of the control group. A strong inverse correlation was seen between plasma plasminogen activator inhibitor-1 (PAI-1) activity and Ks (r = -0.603, p <0.001) or fiber mass-length ratio (r = -0.565, p <0.001) in the patient group. Corresponding weaker associations of PAI-1 with fibrin gel properties were also present in the control group. In addition, inverse relationships of very low density lipoprotein (VLDL) triglyceride concentrations to Ks (r = -0.362, p <0.001) and fiber mass-length ratio (r = -0.283, p <0.01) were found among the controls. Proneness to formation of tight and rigid fibrin gel networks with abnormal architecture in vitro is in vivo associated with myocardial infarction at a young age. Impaired fibrinolytic function secondary to a raised plasma PAI-1 activity level is associated with abnormal fibrin gel structure.
The Effects on Platelet Aggregation and Prostanoid Biosynthesis of two Parenteral Analgesics: Ketorolac Tromethamine and Dipyrone
Authors: geisslinger G , Peskar B A , Pallapies D , Sittl R , Levy M , Brune K 
Published: July 2018

SummaryThe pharmacokinetics and effects on platelet function of dipyrone (1.0 g; 2.5 g; i. v.) and ketorolac tromethamine (30 mg; i.m.) were studied in a three-way crossover study in twelve healthy subjects. The biosynthesis of thromboxane A2 in clotting whole blood ex vivo as well as collagen-induced platelet aggregation were determined before and up to 48 h after administration. Both prostanoid biosynthesis and platelet aggregation were inhibited by ketorolac tromethamine for a significantly longer period of time than by both doses of dipyrone. The changes in platelet functions correlated well with the serum concentrations of ketorolac or 4-methylaminoantipyrine and 4-aminoantipyrine. Using the sigmoidal Emax model the mean serum concentration (SD) of ketorolac, 4-methylaminoantipyrine and 4-aminoantipyrine inhibiting platelet TXB2 generation by 50% (EC50) in vitro was found to be 0.088 ± 0.031, 1.2 ± 0.3 and 10.2 ± 3.4 µg ml-1, respectively. In conclusion the recovery of platelet function after dipyrone administration is faster as compared to ketorolac tromethamine. This is in line with clinical observations and may be an advantage when these drugs are given as postoperative analgesics at the doses tested.
Antithrombotic Effect of Human Recombinant Tissue Factor Pathway Inhibitor on Endotoxin-induced Intravascular Coagulation in Rats: Concerted Effect with Antithrombin
Authors: Kamikubo Yu-ichi , Hamuro Tsutomu , Matsuda Jun-ichi , Shinya Noriko , Miyamoto Seiji , Funatsu Akinobu , Kato Hisao 
Published: July 2018

SummaryIn our current study, we examined the antithrombotic effect of Chinese hamster ovary cell-derived human recombinant tissue factor pathway inhibitor (h-rTFPI) by intravenous injection of h-rTFPI with or without antithrombin into endotoxin-treated rats. An injection of h-rTFPI at a high dose (4 mg/kg of h-rTFPI or three doses of 1 mg/kg) significantly prevented the decrease of fibrinogen and factor VIII and the increase of fibrin/fibrinogen degradation products and glutamic-pyruvic transaminase in rats, while a single injection of 1 mg/kg of h-rTFPI or 250 U/kg of antithrombin did not significantly prevent intravascular coagulation. However, a simultaneous injection of 1 mg/kg of h-rTFPI and 250 U/kg of antithrombin did significantly prevent intravascular coagulation. From the studies on the clearance rate and immunohistochemical staining of injected h-rTFPI into normal rats, we found that most of the intravenously-injected h-rTFPI was localized on the central vein and sinusoids in the liver and catabolized via the proteoglycan-mediated pathway with a half-life of 48 min. These results suggest that h-rTFPI and antithrombin prevented endotoxin-induced intravascular coagulation in concert by binding to the vascular walls of the liver and by inhibiting fibrin formation on Kupffer cells in hepatic sinusoids.
Coagulation and Fibrinolytic Profile of Paediatric Patients Undergoing Cardiopulmonary Bypass
Authors: Chan Anthony K C , Leaker Michael , Burrows Frederick A , Williams William G , Gruenwald Colleen E , Whyte Linda , Adams Margaret , Brooker Lu Ann , Adams Helen , Mitchell Lesley , Andrew Maureen 
Published: July 2018

SummaryThe haemostatic system and the use of heparin during cardiopulmonary bypass (CPB) have been studied extensively in adults but not in children. Results from adult trials cannot be extrapolated to children because of age-dependent physiologic differences in haemostasis. We studied 22 consecutive paediatric patients who underwent CPB at The Hospital for Sick Children, Toronto. Fibrinogen, factors II, V, VII, VIII, IX, XI, XII, prekallikrein, protein C, protein S, antithrombin (AT), heparin cofactor II, α2-macroglobulin, plasminogen, α2-antiplas- min, tissue plasminogen activator (tPA), plasminogen activator inhibitor, thrombin-AT complexes (TAT), D-dimer, heparin (by both anti-factor Xa assay and protamine titration) and activated clotting time (ACT) were assayed perioperatively. The timing of the sampling was: pre heparin, post heparin, after initiation of CPB, during hypothermia, post hypothermia, post protamine reversal and 24 h post CPB. Plasma concentrations of all haemostatic proteins decreased by an average of 56% immediately following the initiation of CPB due to haemodilution. During CPB, the majority of procoagulants, inhibitors and some components of the fibrinolytic system (plasminogen, α2AP) remained stable. However, plasma concentrations of TAT and D-dimers increased during CPB showing that significant activation of the coagulation and fibrinolytic systems occurred. Mechanisms responsible for the activation of haemostasis are likely complex. However, low plasma concentrations of heparin (<2.0 units/ml in 45% of patients) during CPB were likely a major contributing etiology. ACT values showed a poor correlation (r = 0.38) with heparin concentrations likely due to concurrent haemodilution of haemostatic factors, activation of haemostatic system, hypothermia and activation of platelets. In conclusion, CPB in paediatric patients causes global decreases of components of the coagulation and fibrinolytic systems, primarily by haemodilution and secondarily by consumption.
Differential Expression of Low Mr GTP-binding Proteins in Human Megakaryoblastic Leukemia Cell Line, MEG-01, and their Possible Involvement in the Differentiation Process
Authors: Nagata Koh-ichi , Okano Yukio , Nozawa Yoshinori 
Published: July 2018

SummaryThe expression of various low Mr GTP-binding proteins at various states of differentiation of a human megakaryoblastic leukemia cell line, MEG-01, was analyzed using thermocycle amplification of mRNA and immunoblotting. MEG-01 cells were found to express mRNAs of rap1A, rap1B, rap2B, ralA, rhoA, rac1, rac2, CDC42Hs, rab1, rab3B, rab6, ram and ran, but not rab4, and the proteins of Rap 1, Rap2, RhoA, Rac1, Rac2, Rab3B, Rab4, Rab6 and Rab8 were expressed. Differentiation of MEG-01 cells induced by 100 nM 12-O-tetradecanoylphorbol-13-acetate revealed the considerable increases in mRNA expression of rap1B, rab3B, rabA, ram and ran whereas the levels of rap2B, rhoA and rac1 decreased. During the differentiation process, significant changes in protein levels of Rap1, RhoA, Rac1, Rac2, Rab3B, Rab4 and Rab6 were observed among three subcellular (cytosol, Triton X-100-soluble membrane and -insoluble cytoskeleton) fractions. The present investigation may be useful for the study of the megakaryocyte differentiation.