bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lipoprotein(a) Levels and Isoforms and Fibrinolytic Activity in Postmenopause – Influence of Hormone Replacement Therapy
Authors: Cano Antonio , Falcó Cristina , España Francisco , Gilabert Juan , Grancha Salvador , Aznar Justo , Estellés Amparo 
Published: March 2018

SummaryEpidemiological studies suggest that hormone replacement therapy (HRT) decreases the risk of cardiovascular disease in postmenopausal women via several mechanisms, including modifications in the fibrinolytic system and lipoprotein(a) [Lp(a)] levels. The aim of this study was to examine the influence of the levels and isoforms of Lp(a) on fibrinolytic activity in 91 postmenopausal women in comparison with premenopause and analyze the effect of HRT on those parameters. In postmenopause, an increase in plasma Lp(a) and plasminogen activator inhibitor-1 (PAI-1) levels was found. A significant inverse correlation was observed between Lp(a) or PAI-1 levels and plasmin generation. Plasma samples with low molecular weight (MW) apo(a) isoforms showed higher plasmin inhibition than plasmas with high MW apo(a) isoforms and similar levels of total Lp(a) and PAI-1. HRT induced a significant decrease in Lp(a) and PAI-1 levels and an increase in estradiol levels, as well as an increase in fibrinolytic activity. A significant correlation was found between the percentages of variation in Lp(a) levels and in plasmin generation and between the percentages of variation in PAI-1 levels and in the euglobulin lysis time under HRT. In conclusion, the increase in fibrinolytic activity observed in women under HRT could be explained by two independent mechanisms: (a) the decrease in PAI-1 and (b) the decrease in the inhibition of plasmin generation due to the decrease in Lp(a) levels.
Clustering of Integrin αIIb-β3Differently Regulates Tyrosine Phosphorylation of pp72syk, PLCγ2 and pp125FAKin Concanavalin A-stimulated Platelets
Authors: Festetics Enrico , Bertoni Alessandra , Sinigaglia Fabiola , Balduini Cesare , Torti Mauro 
Published: March 2018

SummaryTyrosine phosphorylation of the non-receptor tyrosine kinases pp72sykand pp125FAKand of the γ2 isoform of phospholipase C (PLCγ2) in human platelets stimulated with the lectin Concanavalin A was investigated. Concanavalin A induced the rapid tyrosine phosphorylation of pp72sykand PLCγ2 with a similar kinetics, while tyrosine phosphorylation of pp125FAKoccurred in a later phase of platelet activation. When compared with other platelet agonists, Concanavalin A revealed to be at least as potent as collagen in inducing tyrosine phosphorylation of PLCγ2 and pp125FAK, while tyrosine phosphorylation of pp72sykinduced by the lectin was much stronger than that induced by thrombin or collagen. Concanavalin A-induced tyrosine phosphorylation of pp72syk, PLCγ2 and pp125FAKwas not dependent on platelet aggregation as it occurred normally even in the absence of sample stirring and when fibrinogen binding to integrin αIIb-β3was inhibited by the peptide RGDS. Tyrosine phosphorylation of pp72syk, PLCγ2 and pp125FAKrequired the binding of the lectin to the platelet surface, but was not observed in platelets treated with succinyl-Concanavalin A, a derivative of the lectin that interacts with the same receptors but does not promote clustering of membrane glycoproteins. Moreover, the aggregation-independent tyrosine phosphorylation of pp125FAKand pp72sykinduced by Concanavalin A required the expression of integrin αIIb-β3on the platelet surface as it was strongly inhibited in platelets from patients affected by Glanzmann thrombasthenia. By contrast, tyrosine phosphorylation of PLCγ2 occurred normally also in thrombasthenic platelets stimulated with Concanavalin A. These results demonstrate that, even in the absence of aggregation, the clustering of integrin αIIb-β3induced by Concanavalin A on the platelet surface directly promotes tyrosine phosphorylation of pp72sykand pp125FAKand provide further evidence that the oligomerization of the fibrinogen receptor promoted by its natural ligand during platelet aggregation may be responsible for the tyrosine phosphorylation of these proteins induced by physiological agonists.
Assay of von Willebrand Factor (vWF)-cleaving Protease Based on Decreased Collagen Binding Affinity of Degraded vWF
Authors: Gerritsen Helena , Turecek Peter , Schwarz Hans , Lämmle Bernhard , Furlan Miha 
Published: March 2018

SummaryPatients with thrombotic thrombocytopenic purpura (TTP) have a deficiency of von Willebrand factor (vWF)-cleaving protease, whereas patients with hemolytic-uremic syndrome (HUS) show normal activity of this protease. Present methods for assaying vWF-cleaving protease by immunoblotting are time-intensive and cumbersome. We therefore developed a new functional assay based on the preferential binding of high-molecular-weight forms of vWF to collagen. In this assay, the diluted plasma sample to be tested is added to normal human plasma in which protease activity had been abolished. The vWF present in the protease-depleted plasma is digested by the vWF-cleaving protease in the test plasma. The proteolytic degradation leads to low-molecular-weight forms of vWF, which show impaired binding to microtiter plates coated with human collagen type III. The collagen-bound vWF is quantified using a peroxidase-conjugated rabbit antibody against human vWF. The values of vWF-cleaving protease activity in tested plasma samples are read from a calibration curve achieved by incubating the vWF-substrate with dilutions of a normal human plasma pool (NHP). Testing of plasma from patients with TTP and HUS showed that the assay can be used to distinguish between these two syndromes. The presence of an inhibitor can be detected by carrying out the test after incubation of NHP with the patient plasma sample, thus enabling differentiation of patients with familial TTP from those with non-familial TTP.
Atorvastatin Increases ecNOS Levels in Human Platelets of Hyperlipidemic Subjects
Authors: Tannous Marie , Cheung Raphael , Vignini Arianna , Mutus Bulent 
Published: March 2018

Summary
Background. The purpose of this study was to probe the pleiotrophic effects of Atorvastatin on intraplatelet-nitric oxide metabolism. Methods and Results. Hyperlipidemic subjects (n = 19) were treated for 1 month (following a 3-week washout) with either Atorvastatin or placebo in a double-blinded randomized (n = 2, crossover), placebo-controlled study. Changes in the levels of intraplatelet nitric oxide synthase, nitrotyrosine were correlated with cholesterol, LDL-C, HDL-C and triglyceride levels. These studies indicate that with atrovastatin ecNOS levels increased on average by ~1.7-fold (paired t-test p = 0.009). Interestingly, levels of nitrotyrosylated platelet proteins, an indication of peroxynitrite damage, decreased as ecNOS levels increased in presence of the drug (paired t-test p = 0.33). Atorvastatin, at 10 mg per day, lowered cholesterol and LDL-C levels in all patients with the average lowering of ~21% and ~17% respectively. The effect on HDL was not significant whilst triglyceride levels were lowered by an average of ~18%. Conclusions. This study adds to the volume of evidence that statins have beneficial effects other than lipid lowering. Here, Atorvastatin is shown to significanly elevate intraplatelet ecNOS levels in hyperlipidemic subjects without affecting iNOS expression. The net result of this would be the elevation of NO production which would promote platelet deaggregation and vasodilation.
Automated Latex Agglutination and ELISA Testing Yield Equivalent D-Dimer Results in Patients with Recent Myocardial Infarction
Authors: Zareba Wojciech , Horan John , Moss Arthur , Kanouse Joel ,   for the THROMBO Research Investigators, Marder Victor 
Published: March 2018

SummaryOur previous prospective study of post-infarction patients described a strong and significant association of increased plasma D-dimer concentrations in those who experienced a subsequent coronary death or non-fatal myocardial infarction. In the present study, we compare results on stored plasma obtained two months after the index myocardial infarction from 1,038 patients of this trial, using a simple automated latex agglutination (LA) assay in parallel with the standard ELISA test. Results show a somewhat higher mean value for the LA assay (702 ± 1092 vs. 638 ± 986 ng/ml, p = 0.0002), a strong linear correlation of the two assays (r = 0.86) and 88% agreement for values below 500 ng/ml by the ELISA test. D-dimer concentrations determined by each assay were highly correlated in patients with subsequent coronary artery events (p = 0.93) and quartile values for both the LA and ELISA were equally predictive of such events (p = 0.003 and p = 0.001, respectively). This is the first demonstration that a latex agglutination assay for D-dimer can be used to assess the prognostic risk of recurrent coronary thrombotic disease after myocardial infarction
Dermatan Sulfate and LMW Heparin Enhance the Anticoagulant Action of Activated Protein C
Authors: Fernández José , Petäjä Jari , Griffin John 
Published: March 2018

SummaryUnfractionated heparin potentiates the anticoagulant action of activated protein C (APC) through several mechanisms, including the recently described enhancement of proteolytic inactivation of factor V. Possible anticoagulant synergism between APC and physiologic glycosaminoglycans, pharmacologic low molecular weight heparins (LMWHs), and other heparin derivatives was studied. Dermatan sulfate showed potent APC-enhancing effect. Commercial LMWHs showed differing abilities to promote APC activity, and the molecular weight of LMWHs correlated with enhancement of APC activity. Degree of sulfation of the glycosaminoglycans influenced APC enhancement. However, because dextran sulfates did not potentiate APC action, the presence of sulfate groups per se on a polysaccharide is not sufficient for APC enhancement. As previously for unfractionated heparin, APC anticoagulant activity was enhanced by glycosaminoglycans when factor V but not factor Va was the substrate. Thus, dermatan sulfate and LMWHs exhibit APC enhancing activity in vitro that could be of physiologic and pharmacologic significance.
The Effects of Angiotensin Metabolites on the Regulation of Coagulation and Fibrinolysis in Cultured Rat Aortic Endothelial Cells
Authors: Tsuji Hajime , Masuda Haruchika , Kasahara Teruhisa , Yoshizumi Masami , Sugano Tatsuya , Kimura Shinzo , Kawano Hidehiko , Kunieda Yasufumi , Yano Shingo , Nakagawa Katsumi , Kitamura Hidetsugu , Nakahara Yoshifumi , Sawada Shohei , Nakagawa Masao , Nishimura Hiromi 
Published: March 2018

SummaryNot only angiotensin II (Ang II) but also other angiotensin metabolites such as angiotensin I (Ang I), angiotensin III (Ang III), angiotensin IV, or angiotensin 1-7 have recently been reported to have various activities. Few data, however, are available on the regulation of thrombus formation. In this study, we investigated the effects of angiotensin metabolites on the mRNA expression of tissue factor (TF), tissue factor pathway inhibitor (TFPI), plasminogen activator inhibitor-1 (PAI-1), and tissue type plasminogen activator (TPA) in cultured rat aortic endothelial cells. None of the used angiotensin metabolites altered TFPI or TPA mRNA expression levels. Ang I, Ang II, and Ang III made TF and PAI-1 mRNA inductions which were inhibited by an selective antagonist of angiotensin II type 1 receptors. These metabolites made TF predominant to TFPI or PAI-1 to TPA, and could render endothelial cells thrombogenic.
Differential Effects of Dietary Supplementation with Fish Oil or Soy Lecithin on Human Platelet Adhesion
Authors: Carletto Antonio , Guarini Patrizia , Galvani Simonetta , Biasi Domenico , Bellavite Paolo , Corrocher Roberto , Andrioli Giuseppe 
Published: March 2018

SummaryTo investigate the possible regulating role of ω-6 and of ω-3 fatty acids on platelet adhesiveness, we randomised 60 volunteers into three groups to take 20 ml (equivalent to 0.3 g ω-6, 3.6 g ω-3; ω-6/ω-3 ratio 0.1) per day of a fish oil supplement, or to take 25 g (equivalent to 1.5 g ω-6, 0.5 g ω-3; ω-6/ω-3 ratio 3) per day of a soy lecithin supplement, or to continue on their usual diet without any supplement (control group) for a period of 15 days. Platelet adhesion on fibrinogen-coated 96-well microtitre plates was evaluated in the resting condition and after stimulation with 2 ωM ADP or 0.02 U/ml thrombin. Compared to the values before the experimental period, the fish oil group showed a significant reduction in stimulated adhesion (with ADP: from 18.8% to 15.6%, p <0.01; with thrombin: from 24.4% to 20.8%, p <0.005), whereas no difference was noted in the resting condition (from 3.6% to 3.5%, NS). In the soy lecithin group, platelet adhesion was increased in all test conditions (with ADP: from 18.7% to 23.2%, p <0.001; with thrombin: from 24.0% to 29.9%, p <0.001; resting: from 3.5% to 6.6%, p <0.001). No significant changes were observed in the control group. A good correlation was found between platelet adhesion data and the changes in the platelet fatty acid ω-6/ω-3 ratio caused by the different supplementations. Our results indicate an inhibitory effect of fish oil rich in ω-3 fatty acids on stimulated human platelet adhesiveness and a stimulatory effect of soy lecithin rich in ω-6 fatty acids on resting and stimulated adhesion. They suggest moreover that the ω-6/ω-3 ratio is a determinant of platelet adhesion.
Analysis of CD39/ATP Diphosphohydrolase (ATPDase) Expression in Endothelial Cells, Platelets and Leukocytes
Authors: Koziak Katarzyna , Sévigny Jean , Robson Simon , Siegel Jonathan , Kaczmarek Elzbieta 
Published: March 2018

SummaryPurinergic signaling may influence hemostasis, inflammatory responses and apoptosis. Therefore, hydrolysis of extracellular ATP and ADP by the ATP diphosphohydrolase (ATPDase) could regulate these processes. We have previously demonstrated the identity between the vascular ATPDase and CD39. Here we show that levels of CD39 expression correlate with ATPDase activity in human endothelial cells (EC), platelets and selected monocyte, NK, and megakaryocyte cell lines. Western blotting revealed one to three isoforms of CD39/ ATPDase; mobility variations of major protein resulted from post-translational modifications. Northern blotting and primer extension indicated two major mRNA transcripts and one transcription start point, respectively. In addition, mRNAs specific for purinergic P2 receptors were detected in all of the investigated cells, suggesting that the co-expressed CD39/ATPDase may regulate purinergic signaling. Thrombotic and inflammatory responses may be modulated by the expression of CD39/ATPDase.
Novel Deletion and Insertion Mutations Cause Splicing Defects, Leading to Severe Reduction in mRNA Levels of the A Subunit in Severe Factor XIII Deficiency
Authors: Izumi Tomonori , Nagaoka Utako , Saito Tetsuo , Takamatsu Junki , Saito Hidehiko , Ichinose Akitada 
Published: March 2018

SummaryIn order to explore molecular mechanisms for factor XIII deficiency, a patient (Nagoya I) was examined at the DNA and RNA levels. Nucleotide sequence analysis of the patient’s DNA amplified by PCR revealed that he had a 20 bp deletion at the boundary of exon I/intron A, and an insertion of T in the invariant GT dinucleotide at the splicing donor site of exon IV/intron D. The presence of these heterozygous mutations was confirmed by restriction digestion of the amplified fragments of the proband and his parents. RT-PCR analysis demonstrated that only one kind of mRNA without exon IV was detected in Nagoya I, although its level was greatly reduced to less than 5% of normal. The other defective allele of the A subunit gene containing the 20 bp deletion was not detected. Thus, both mutations impaired normal processing of mRNA for the A subunit, resulting in his severe factor XIII deficiency.
Standardization of the APC Resistance Test. Effects of Normalization of Results by Means of Pooled Normal Plasma
Authors: Chantarangkul Veena , Negri Barbara , Mannucci Pier Mannuccio , Tripodi Armando 
Published: March 2018

SummaryResults for APC resistance tests are expressed as the ratio of the clotting time with and without APC (APC ratio). Normalization by dividing the patient’s APC ratio by that of the pooled normal plasma (PNP) (n-APC ratio) was proposed to minimize between-lot reagent variability. To evaluate the merits of different expressions of the results, sets of 80 coded frozen plasmas from carriers (n = 30), non-carriers (n = 30) of the FV:Q506 mutation and 10 copies each of two control plasmas were sent to 7 expert laboratories which were asked to assess APC resistance by their methods. Results were expressed as APC ratio and nAPC ratio by the local PNP and 2 common PNP (A and B). These contained plasmas from the same (n = 20) non-carriers. In PNP A, plasma from one non-carrier was replaced with that from one heterozygous carrier. The merits of different expression of results were judged by (i) within-laboratory reproducibility; (ii) discrimination of carriers from non-carriers; (iii) between-method comparability of results. The influence of FV:Q506 plasma in the preparation of PNP was also assessed. Reproducibility, generally good even with results expressed as APC ratio (median CV 4.6% and 3.0% for normal and abnormal control), was not changed by normalization. Discrimination did not change whatever the method of result expression. Between-method comparability of results was scarcely affected by normalization with the local PNP, whereas it was considerably improved after normalization with the common PNP, but only for the non-carriers. APC ratios for PNP A by all methods were significantly lower than those for PNP B. Thus, the presence of mutant FV in a proportion as low as 2.5% may reduce the APC ratio of the PNP.
Sex Differences in the Determinants of Fibrinolytic Activity
Authors: Cooper J. A. , Howarth D. J. , Meade T. W. , Miller G. J. , MacCallum P. K. 
Published: March 2018

SummaryImpaired whole blood fibrinolytic activity (FA), measured by the dilute clot lysis time (DCLT), is associated with first episodes of ischaemic heart disease (IHD) in the Northwick Park Heart Study in men, especially under 55 years, and in women. In a community-based study to investigate possible determinants of the DCLT, and therefore to assess which fibrinolytic components might be predictors of first IHD events, we measured fibrinolytic variables in a sub-sample of 150 healthy adults (73 males, 77 females) randomly selected from a single general practice.Most of the variance in DCLT (68% in men, 63% in women) was explained by tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor type-1 (PAI-1) activities. In multiple regression analysis there was a significant difference in the strength of the association of t-PA activity with DCLT in men compared to women (test for interaction p = 0.05), the association of t-PA activity with DCLT being significant in males but not in females. Plasma PAI-1 activity was strongly associated with DCLT in both sexes. There was no independent association of DCLT with plasma fibrinogen, t-PA antigen, other fibrinolytic inhibitors, body mass index, serum lipids or C-reactive protein.Plasma PAI-1 activity in females and both t-PA and PAI-1 activities in males are the main determinants of whole blood FA measured by DCLT. It is therefore likely that these modulators of the plasma fibrinolytic system are associated with the onset of first clinical episodes of IHD. Elevated levels of t-PA antigen were positively associated with DCLT after adjustment for age and sex and therefore indicate impaired rather than enhanced FA. Further studies of the association of FA with risk of IHD should include not only “global” measures but also assessment of t-PA and PAI-1 activities, particularly as our results suggest that their associations with IHD may differ in men and women.
Atrial Natriuretic Peptide Inhibits the Expression of Tissue Factor and Plasminogen Activator Inhibitor 1 Induced by Angiotensin II in Cultured Rat Aortic Endothelial Cells
Authors: Tsuji Hajime , Nishimura Hiromi , Kasahara Teruhisa , Sugano Tatsuya , Masuda Haruchika , Nakagawa Katsumi , Nakahara Yoshifumi , Kitamura Hidetsugu , Yamada Keizou , Yoneda Mitsuru , Sawada Shohei , Nakagawa Masao , Yoshizumi Masami 
Published: March 2018

SummaryThe pharmacological characteristics of atrial natriuretic peptide (ANP), such as natriuresis, vasodilation, or suppression of smooth muscle cell proliferation, are well investigated. However, this is the first study to report its role on blood coagulation and fibrinolysis mediated by vascular endothelial cells. In this study, the effects of ANP on the enhanced expression of tissue factor (TF) and plasminogen activator inhibitor 1 (PAI-1) by angiotensin II (Ang II) in cultured rat aortic endothelial cells (RAECs) were examined. The expressions of TF and PAI-1 mRNA were detected by northern blotting methods. The activities of TF on the surface of RAECs and PAI-1 in the culture media were measured by chromogenic assay. ANP suppressed mRNA expressions of TF and PAI-1 induced by Ang II in a concentration-dependent manner. This suppression was accompanied by the decreased activities of TF and PAI-1.
Role of Integrin αvβ3 in Vascular Biology
Authors: Byzova Tatiana , Rabbani Ramin , D’Souza Stanley , Plow Edward 
Published: March 2018

IntroductionA defining characteristic of vascular cells is their adhesive status. The predominant cells of the blood vessel, endothelial cells (EC) and smooth muscle cells (SMC), are normally adherent but can be induced to migrate in response to vascular injury and angiogenic stimuli. The circulating blood cells are ordinarily nonadhesive but can rapidly acquire an adhesive phenotype in response to physiologic and pathophysiologic stimuli. As prime examples, platelets become adherent to the subendothelial matrix and to one another during thrombus formation, and leukocytes first adhere to EC and then transmigrate during the inflammatory response. At a molecular level, the adhesive properties of the vascular cells are determined by the adhesion receptors on their cell-surface and the functional state of these receptors. To match the variety of requisite cellular adhesive reactions, the repertoire of adhesion receptors expressed by vascular cells is broad. Multiple representatives of the immunoglobulin-like, the selectin, the cadherin and the integrin families of adhesion receptors are present on and have been implicated in the functions of the vascular cells. The importance of these adhesion receptors in vascular cell function is underscored by the severe pathogenetic consequences of their congenital deficiencies, such as in Glanzmann’s thrombasthenia, LAD (Leucocyte Adhesion deficiency) I and LAD II (1-3).The integrins are the largest and most broadly distributed of the families of cellular adhesion receptors. Of the integrins, αvβ3, originally identified as the vitronectin receptor, is particularly widely distributed. It is expressed at variable density on many types of vascular cells. Obviously, the adhesive properties of a cell are determined by its full repertoire of adhesion receptors. As an example, the adhesion of EC to fibrinogen/fibrin is mediated by no fewer than five receptors. Nevertheless, it is possible to dissect out the contributions of individual adhesion receptors, and αvβ3 has been implicated in many functional responses of vascular cells. This review focusses upon the role of αvβ3 in vascular cell biology. Other contributions of this multifunctional receptor, such as its role in neoplastic growth and invasion and in osteoclast-mediated bone resorption, are beyond the scope of this article and have been reviewed elsewhere (4, 5).