bluuebunny/crossref_metadata_2025 huggingface dataset:
Von Willebrand’s Disease caused by Compound Heterozygosity for a Substitution Mutation (T1156M) in the D3 Domain of the Von Willebrand Factor and a Stop Mutation (Q2470X)
Authors: Lethagen Stefan , Isaksson Christina , Schaedel Charlotta , Holmberg Lars
Published: March 2018

Hereditary defects of the von Willebrand factor (VWF) gene cause von Willebrand’s disease (VWD) which shows great variability dependent on the nature and location of the mutation. We here describe the characteristics of a substitution of methionine for threonine 1156 in the D3 domain of the VWF, i.e. the domain involved in the intracellular multimerization of pro-VWF dimers. A VWD patient with severe symptoms was a compound heterozygote for the T1156M mutation and a null allele (Q2470X) on the other chromosome. This led to marked reduction of plasma VWF concentration to about 0.05 U/ml and an abnormality of VWF multimers as in type 2A VWD. Expression in vitro of the mutation demonstrated that 1156M-VWF is secreted from COS-7 cells in a much reduced amount and lacking large multimers. When coexpressed with normal VWF 1156M-VWF decreased the secretion of normal VWF in a dose-dependent manner, the secreted VWF showing all the multimers. Two relatives of the propositus were single heterozygotes for the T1156M mutation and were either asymptomatic or had the manifestations of mild type 1 VWD. The expression data and studies of platelet VWF indicate that the T1156M mutation results in intracellular retention of VWF rather than impaired synthesis. Three other members of the family were heterozygotes for the Q2470X mutation and demonstrated the variable expressivity of a null allele.
Effects of Enhanced P2X1 Receptor Ca2+ Influx on Functional Responses in Human Platelets
Authors: Rolf Michael , Mahaut-Smith Martyn
Published: March 2018

G-protein-coupled P2Y1 and P2Y12 receptors play key roles in platelet activation, however the importance of ionotropic P2X1 receptors remains unclear. Platelet P2X1 responses are highly labile in vitro, but were greatly enhanced by increasing [Ca2+]o in the range 1–10 mM. The P2X1 agonist α,β-MeATP stimulated a shape change which saturated at peak [Ca2+]i of ≥ 400 nM, without evidence for aggregation. The maximal P2X1-evoked transmission decrease was 82% of that obtained via P2Y1 receptors. α., β-MeATP caused a disc to sphere transformation in virtually all platelets, but lacked the long processes produced by ADP. Following block of P2Y1 receptors with A3P5PS, co-stimulation with α., β-MeATP and ADP failed to induce aggregation despite the generation of peak [Ca2+]i responses similar to those stimulated via P2Y1 receptors. Therefore early, transient Ca2+ influx via P2X1 receptors can contribute to platelet activation by stimulating a significant morphological change, but does not readily synergise with P2Y12 receptors to support aggregation.
Magnetic resonance imaging of tumor vasculature
Authors: Chetrit-Dadiani Maya , Bogin Liora , Furman-Haran Edna , Degani Hadassa
Published: March 2018

Angiogenic activity and formation of a vascular network facilitate tumor perfusion and play a critical role in tumor growth and metastasis. Tumor vasculature may be visualized by means of parametric imaging of specific morphological and physiological characteristics that collectively describe its properties. In this review, we describe advanced magnetic resonance imaging (MRI) techniques that have been developed in order to image and quantify the distribution of tumor vasculature throughout the tumor and characterize its function. These techniques have been used to monitor changes in the magnetic resonance signal intensity of tissue water hydrogens generated by intrinsic effects, as well as by exogenous contrast agents administered into the blood circulation. We further describe specific applications of magnetic resonance imaging using a contrast agent, gadolinium diethylene triamine penta-acetic acid (GdDTPA), which has long been approved for clinical use. Examples include studies of the vascular properties of breast cancer tumors and metastases in animal models, as well as of breast cancer vasculature in patients. We also discuss the use of MRI to improve breast cancer diagnosis in humans by quantifying the permeability of the tumor vasculature. By maximizing the spatial resolution of the images in both animal and human studies, the capacity of magnetic resonance imaging to enhance our understanding of the processes regulating tumor angio-genesis, and improve the diagnosis of cancer, could be clearly demonstrated.
The influence of exogenous magnesium chloride on the apparent INR determined with human, rabbit, and bovine thromboplastin reagents
Authors: Witteveen Evelina , Meeuwisse-Braun Joyce , van der Meer Felix , van den Besselaar Anton
Published: March 2018

Magnesium ions can shorten the tissue factor-induced coagulation time. Some blood collection systems with sodium citrate are contaminated with variable amounts of magnesium and influence the results of the prothrombin time (PT) test. The aim of the study was to determine the dose-response relationship between exogenous magnesium chloride added to blood and the PT and the international normalized ratio (INR). Blood specimens from twenty patients on oral anticoagulant therapy were investigated. Four different types of thromboplastin reagents were used: recombinant human, human placenta, rabbit brain, and bovine brain combined with adsorbed bovine plasma. With all four reagents, exogenous magnesium induced a reduction of the apparent INR. Bovine thromboplastin was not as responsive to magnesium as the human and rabbit reagents. The magnitude of the INR deviation induced by 0.1 mmol/l magnesium in the blood was smaller than 10% in all patient samples. At 0.5 mmol/l magnesium in the blood, 10-35% of the patient samples had INR deviations greater than 10%, depending on the thromboplastin reagent used.
Chemical crosslinking of urokinase to pulmonary surfactant protein B for targeting alveolar fibrin
Authors: Ruppert Clemens , Markart Philipp , Schmidt Reinhold , Grimminger Friedrich , Seeger Werner , Lehr Claus-Michael , Günther Andreas
Published: March 2018

Intraalveolar fibrin formation is a consistent finding in acute inflammatory and chronic interstitial lung disease. Polymerization of fibrin in the presence of pulmonary surfactant results in far-reaching incorporation of the hydrophobic surfactant compounds into the growing fibrin matrix, with loss of surface activity, altered fibrin structure and reduced susceptibility of the clot to fibrinolysis. For specific targeting of such alveolar fibrin, we designed a hybrid molecule consisting of the catalytic domain of urokinase (B-chain) and the hydrophobic surfactant protein B (SP-B), termed SPUC. The urokinase B-chain, obtained by limited reduction of human two-chain-urokinase (u-PA) and subsequent affinity purification, was chemically coupled to SP-B in a semi-organic solvent system using a hetero-bifunctional crosslinker. Purification of the chimeric proteins included reversed phase and cation exchange chromatography. SDS-PAGE and Western Blotting with immunostaining were employed for biochemical characterization of the conjugate. Chromogenic substrate assays, 125I-based fibrin plate assays, active site titration and surface tension measurements (pulsating bubble surfactometer) were performed to analyze the specific fibrinolytic activity of the conjugate and its surface activity. SPUC was found i) to be assembled stoichiometrically in a 1:1 fashion (SP-B:u-PA), ii) to fully retain the biophysical activity as compared to native SP-B and iii) to also retain the fibrinolytic activity. SPUC was 2-3 fold more effective in lysis of surfactant containing clots and 5-fold more resistant against plasminogen activator 1 (PAI-1) as compared to the native u-PA. We conclude that urokinase and SP-B can be chemically crosslinked, thereby yielding a fibrinolytic enzyme suitable for targeting alveolar fibrin.
Prolonged elevations in haemostatic and rheological responses following psychological stress in low socioeconomic status men and women
Authors: Kunz-Ebrecht Sabine , Rumley Ann , Lowe Gordon , Steptoe Andrew
Published: March 2018

Low socioeconomic status (SES) and psychological stress are associated with increased risk of coronary heart disease, and both may influence haemostatic responses. Von Willebrand factor (vWF), Factor VIII, plasma viscosity, haematocrit, blood viscosity, tissue plasminogen activator (t-PA) and fibrin D-dimer were measured at rest and following stressful tasks in 238 middle-aged British civil servants. SES was defined by grade of employment. Lower SES was associated with higher resting vWF, Factor VIII and plasma viscosity. Psychological stress stimulated increases in haemostatic and rheological factors. Initial stress responses did not vary with SES, but Factor VIII, plasma viscosity and blood viscosity remained more elevated 45 minutes post-stress in lower SES participants. High blood pressure stress reactivity was also associated with greater haemostatic responses. We conclude that lower SES is characterised by more prolonged elevations in procoagulant responses following psychological stress, and that these processes might contribute to increased cardiac risk.
Diabetes duration may modify the association between genetic variation in the glycoprotein Ia subunit of the platelet collagen receptor and risk of severe diabetic retinopathy: a working hypothesis
Authors: Agardh Elisabeth , Teramura Gayle , Gaur Prashart , Gaur Lakshmi , Agardh Carl-David , Reiner Alexander
Published: March 2018

Genetic factors appear to contribute to the severity and progression of diabetic retinopathy. We assessed the associations of the C807T and Glu505Lys variants of the glycoprotein Ia ( 2 integrin) subunit of the platelet/endothelial collagen receptor and risk of retinopathy in a population-based survey of 288 diabetic patients in one Swedish community. Neither variant was associated with retinopathy risk overall. However, the 807T variant was associated with increased risk of severe retinopathy, and the association was modified by diabetes duration. Among patients with diabetes of longer duration ( 25 years), the 807T variant was strongly associated with risk of severe retinopathy (odds ratio 7.49, 95% confidence interval 1.75 to 32.1). There was no association between the 807T variant and risk of severe retinopathy among patients with diabetes duration <25 years. The Lys505 variant of glycoprotein Ia was associated with an odds ratio for severe retinopathy of 1.88 (95% confidence interval 0.83 to 4.24). Overall, there was a significant interaction between glycoprotein Ia genotype and duration of diabetes on the risk of retinopathy (P-value for interaction = 0.019).These results suggest the hypothesis that genetic variation of platelet glycoprotein Ia may play a particularly important role during the advanced stages of diabetic retinopathy.
Insulin resistance: an atherothrombotic syndrome
Authors: Freeman Mark , Mansfield Michael , Barrett Jenny , Grant Peter
Published: March 2018

The insulin resistance syndrome (IRS) is a clustering of atherothrombotic traits associated with increased vascular risk. We investigated the degree to which the phenotypic correlations between these traits are due to shared genetic and environmental factors.

A multivariate genetic analysis was performed in 537 adults from 89 healthy white north European families. All traits showed significant heritability. BMI had significant genetic correlations with fasting insulin, systolic blood pressure (sBP), plasminogen activator activator inhibitor-1 (PAI-1) and fibrinogen and triglyceride. Fasting insulin had a significant genetic correlation with fibrinogen and triglyceride and Factor VII (FVII). Significant genetic correlations were shown between triglyceride and PAI-1, fibrinogen and FVII. PAI-1 and tissue plasminogen activator (t-PA) showed significant genetic correlation with sBP and with each other. Pleiotropy was demonstrated between fibrino-gen and PAI-1, t-PA and FVII. Significant environmental correlations were also demonstrated.

This study demonstrates pleiotropy between coagulation and fibrinolytic factors. Shared genetic and environmental factors influencing haemostatic, metabolic and anthropometric traits underlie the atherothrombotic nature of the IRS.
A Common Polymorphism Flanking the ATG Initiator Codon of GPIbα Does not Affect Expression and Is not a Major Risk Factor for Arterial Thrombosis
Authors: Corral J. , Lozano M. L. , González-Conejero R. , Martínez C. , Iniesta J. A. , Rivera J. , Vicente V.
Published: March 2018

The platelet membrane glycoprotein (GP) Ibα plays a key role in the initial formation of thrombi. Polymorphisms (VNTR and HPA-2) in this receptor are associated with increased risk of coronary heart disease (CHD) and cerebral vascular disease (CVD). We investigated whether a recently described polymorphism (S/R), due to a single base change (T → C) five nucleotides upstream the initiator codon of GPIbα, might influence the expression of the protein, and be implicated in the development of arterial thrombosis.

One hundred and thirty nine healthy individuals provided blood samples for DNA analysis of platelet GPIbα polymorphisms, and for flow cytometric analysis of the surface expression of the receptor. A group of 20 S/R normal individuals and an identical number of S/S participants, age and sex matched, was investigated for the analysis of the density of various platelet receptors. The distribution of the S/R polymorphism was also analyzed in two case/control studies including 104 CVD patients, 101 CHD patients, and one control age, sex, and environmental risk factors matched for each case patient. Surface density of GPIbα showed no wide variations between individuals, was not influenced by the presence of S or R alleles, nor associated with the VNTR or HPA-2 polymorphisms. The prevalence of the S/R genotype among CVD and CHD patients was not distinct from that in the control groups. We conclude that the S/R polymorphism of GPIbα, flanking the initiator codon of the receptor, does not seem to be associated with surface levels of the protein, and is not an independent risk factor for arterial thrombosis.
Screening for Autoimmune Markers Is Unnecessary during Follow-up of Adults with Autoimmune Thrombocytopenic Purpura and no Autoimmune Markers at Onset
Authors: Vantelon J. M. , Godeau B. , André C. , Bierling P.
Published: March 2018

In an attempt to evaluate the frequency of autoimmune markers in autoimmune thrombocytopenic purpura (AITP) and to determine if autoimmune markers in patients with isolated AITP were associated with particular disease manifestations, we analyzed records of 122 consecutive adults with AITP. Twenty-nine patients (24%) had significant titers of one or several autoimmune markers at AITP onset. Among them, 16 (13%) had antinuclear antibodies. The presence of autoimmune markers did not correlate with presenting feature, response to treatment or long-term outcome of AITP. Six patients (5%) developed seven autoimmune diseases during follow-up, comprising systemic lupus erythematosus, an antiphospholipid syndrome, autoimmune haemolytic anemia (n = 2), Grave’s disease, Hashimoto’s disease and primary biliary cirrhosis. At AITP onset, three of these patients had isolated biological markers of the autoimmune disease they later developed. The annual average incidence rate of autoimmune diseases was 1% per patient-year in the entire group and 0.4% in the group of patients with no autoimmune markers at AITP onset. This low rate is probably due to careful assessment at diagnosis for concomitant overt autoimmune disease. We recommend extensive screening for autoimmune markers at AITP onset, and careful follow-up of patients with autoimmune markers. Routine screening for autoimmune markers during AITP follow-up is not necessary for patients with no autoimmune markers at AITP onset.

Systemic lupus erythematosus (SLE) and other autoimmune disorders can complicate autoimmune thrombocytopenic purpura (AITP) or be diagnosed concomitantly with otherwise unremarkable AITP (1, 2). However, the frequency and prognostic value of isolated autoimmune markers (i. e. not associated with an autoimmune disorder), particularly antinuclear antibodies (ANA) at AITP onset or during follow-up is controversial (3-8). For example, the committee organized by George et al. (9) to write guideline on the diagnosis and treatment of AITP stated that the search for ANA and lupus anticoagulant were of “uncertain appropriateness at diagnosis and during follow-up”. In an attempt to help practicians to make decisions, we analyzed the frequency of autoimmune markers and autoimmune disorders at onset and during the follow-up in 122 adults with AITP and no overt autoimmune disease at diagnosis. These consecutive patients were followed by the same physician for a mean period of 6 years, and had routine screening tests for autoimmune markers and disorders at onset, before steroid therapy, and regularly during follow-up.
Fluvastatin Decreases Soluble Thrombomodulin in Cardiac Transplant Recipients
Authors: Aillaud Marie-Françoise , Habib Gilbert , Kreitmann Bernard , Métras Dominique , Luccioni Roger , Bouvenot Gilles , Juhan-Vague Irène , Ambrosi Pierre
Published: March 2018

We conducted a randomized, placebo controlled, double-blind, cross-over study, to assess the effects of a 4-week fluvastatin therapy on plasma markers of endothelial activation or injury in 20 transplanted heart recipients. The levels of thrombomodulin and von Willebrand factor antigen were higher at baseline in cardiac transplant recipients than in age and sex-matched healthy controls. Plasma total cholesterol showed a 21% reduction on fluvastatin therapy (p = 0.0001). Fluvastatin treatment had no significant effect on creatininemia, plasma cyclosporine, PAI-1 antigen, PAI-1 activity, tPA antigen, and Von Willebrand factor. However, fluvastatin produced a significant decrease of plasma thrombomodulin (66.7 ng/ml on placebo versus 58.8 ng/ml on fluvastatin, p <0.001), suggesting a rapid improvement of endothelial injury in these patients.
The Management of Oral Anticoagulant Therapy: The Patient’s Point of View
Authors: Barcellona Doris , Contu Paolo , Sorano Gian , Pengo Vittorio , Marongiu Francesco
Published: March 2018

The aims of this study were to investigate on the general adhesion of the patients to oral anticoagulant therapy, and particularly on the quality of life of our patients, the doctor-patient relationship and the Centre-patient relationship. For this purpose we administered a questionnaire containing 17 main questions each with a maximum of 4 secondary questions. The questionnaire was administered to two groups of 127 and 137 oral anticoagulated patients (127 males and 137 females, mean age 55 ± 19 years), followed at two Anticoagulation Clinics, in two Italian cities, Cagliari (Sardinia) and Padua (North East Italy). The cities differed in the number of patients monitored and the management modalities of anticoagulation. The results show that oral anticoagulant therapy does not limit the life-style of the patients. Only 11% of the patients complain of limitations to their daily life. Fifty-two percent believe their health has improved, and 87% are not afraid of negative consequences. The doctor-patient relationship is considered very important by 96% of patients. Seventy-eight percent refer to the Anticoagulation Clinic also for other health problems, 93% consider it important to be assessed by the doctor at the Anticoagulation Clinic, while 83% believe the doctor should always hand out the results personally. We conclude that in general oral anticoagulant therapy is accepted by the majority of patients, in spite of the need for periodic monitoring. The doctor-patient relationship should be taken into account, even in the case of a monitored, computer-assisted method of dose-adjustment.
Characterization of Transgenic Mice that Secrete Functional Human Protein C Inhibitor into the Circulation
Authors: van Vuuren A. , Girma Merone , Tiekstra Margriet , Kwast Liane , Koster Johanna , Rijneveld Anita , Elisen Marc , van der Poll Tom , Meijers Joost , Wagenaar Gerry
Published: March 2018

Protein C inhibitor (PCI) is a heparin binding serine protease inhibitor in plasma, which exerts procoagulant activity by inhibiting thrombomodulinbound thrombin or activated protein C (APC). Since the role of PCI in vivo is largely unknown we generated genetically modified mice with expression of human PCI mRNA in hepatocytes only. Three transgenic lines have been characterized. Transgenic mice did not show gross developmental abnormalities. Two lines showed a pericentral and one line showed a periportal expression pattern of human PCI mRNA in the liver. Genetically modified mice secreted a functional transgenic protein into the circulation (3-5 µg/ml plasma in heterozygous mice and 10 µg/ml in homozygous mice), which inhibited human APC activity in the presence of heparin. Interestingly, transgenic mice in which human PCI was expressed periportally in the liver had the highest specific activity. Endogenous mouse PCI mRNA could only be detected in the male and female reproductive system, but not in the liver, indicating that endogenous PCI levels in the circulation are low or even absent in mice. These results demonstrate that the human PCI transgenic mice are a suitable model for studying the in vivo role of PCI in blood coagulation.
Platelets Release their Lysosomal Content In Vivo in Humans upon Activation
Authors: Ciferri Silvia , Emiliani Carla , Guglielmini Giuseppe , Orlacchio Antonio , Nenci Giuseppe , Gresele Paolo
Published: March 2018

Platelets contain, besides α- and δ-granules, lysosomes which store glycohydrolases able to degrade glycoproteins, glycolipids and glycosaminoglycans. While several studies have shown that α- and δ-granule secretion takes place “in vivo” in humans upon platelet activation, no data are available on the “in vivo” release of lysosomes. We have studied the release of platelet lysosomal contents “in vivo” in healthy volunteers at a localized site of platelet activation by measuring markers of lysosomal secretion in the blood oozing from a skin wound inflicted for the measurement of the bleeding-time. The levels of β-N-acetylhexosaminidase (Hex) were 13.1 ± 0.85 mU/ml in bleedingtime blood and 10.2 ± 0.66 mU/ml in plasma (p <0.001). Hex in serum was 16.4 ± 0.72 mU/ml. The levels of β-galactosidase were also higher in bleeding-time blood than in plasma (0.85 ± 0.07 mU/ml vs 0.4 ± 0.05 mU/ml, p <0.001). In bleeding-time blood collected at one minute intervals, Hex rose progressively consistent with ongoing platelet activation and flow-cytometry showed a progressive increase of the expression of LIMP and LAMP-2, two lysosomal associated proteins. In conclusion, our data demonstrate that platelet lysosomal glycohydrolases are released “in vivo” in humans upon platelet activation.
Hypofibrinogenaemia with Compound Heterozygosity for Two γ Chain Mutations – γ 82 Ala→Gly and an Intron Two GT→AT Splice Site Mutation
Authors: Wyatt Jane , May Stephen , George Peter , Brennan Stephen
Published: March 2018

We investigated the molecular basis of hypofibrinogenaemia in a woman with a history of recurrent, pregnancy-associated bleeding, and miscarriage. She had a Clauss fibrinogen of 0.9 mg/ml and SDS PAGE of purified fibrinogen showed a normal pattern of chains. However careful inspection of reverse phase chain separation profiles showed apparent homozygosity for a more hydrophilic form of the γ chain. DNA Sequencing showed only heterozygosity for a CGT→GGT (Ala→Gly) mutation at codon γ82, but further sequencing showed an additional GT splice sequence mutation at the 5’ end of intron 2 of the γ gene. Translation of mRNA containing this intron would result in premature truncation explaining the phenotypic homozygosity of the γ82 Ala→Gly substitution. The patient’s sister had a mild bleeding disorder with hypofibrinogenaemia and she too was a compound heterozygote for the γ mutations. Her nephew had only the novel splice site mutation, while her mother and daughter inherited only the γ82 Ala→Gly substitution.
Use of a New Monoclonal Antibody-Based Enzyme Immunoassay for Soluble Fibrin to Exclude Pulmonary Embolism
Authors: Sanson Bernd-Jan , de Monyé Wouter , Lijmer Jeroen , Huisman Menno , Büller Harry , Nieuwenhuizen Willem , Brandjes Dees P. , Mac Gillavry Melvin ,   the ANTELOPE-Study Group
Published: March 2018

We prospectively evaluated the diagnostic performance of a new soluble fibrin assay in 303 consecutive patients with suspected pulmonary embolism and examined potentially useful cut-off levels at which this disease can be safely excluded. In addition, the diagnostic accuracy was calculated in the subgroups of in- and outpatients. The ROC curve of the assay in the total study cohort had an area under the curve of 0.69. The cut-off level associated with a sensitivity and negative predictive value of 100% was 20 ng/ml, but the specificity was only 4%. The cut-off level with a sensitivity of 90% was 30 ng/ml, which corresponded with a specificity and negative predictive value of 27% and 86%, respectively. The diagnostic performance was comparable in the subgroups of in- and outpatients. We conclude that the soluble fibrin assay has a low diagnostic accuracy and seems unsuitable as a screening test for the exclusion of pulmonary embolism.
Factor Xa Acts as a PDGF-Independent Mitogen in Human Vascular Smooth Muscle Cells
Authors: Braun Marina , Fischer Annett , Wittpoth Michael , Glusa Erika , Schrör Karsten , Bretschneider Ellen
Published: March 2018

This study investigates the mitogenic effect of the coagulation factor Xa in smooth muscle cells (SMC) from human saphenous vein and the procoagulant activity of these cells. Factor Xa elicited a concentrationdependent increase in [3H]thymidine incorporation. This mitogenic effect of factor Xa was inhibited by DX-9065a and BABCH, indicating the requirement of proteolytic activity of the enzyme. Factor Xa activated the MAP kinases ERK1/2 concentration-and time-dependently. PDGF-neutralizing antibodies neither inhibited the increase in [3H]thymidine incorporation nor ERK-1/2 phosphorylation in factor Xa-stimulated cells, suggesting that factor Xa-induced signaling and mitogenic activity in human venous SMC are independent of PDGF. Exposure of SMC to recalcified plasma resulted in a significant thrombin generation which was inhibited by anti-tissue factor antibody, tissue factor pathway inhibitor, inactivated factor VIIa and DX-9065a. These data indicate that interaction of SMC with the clotting system may contribute to venous graft disease, i.e. thrombus formation and intimal hyperplasia.
TERIMA-2: National Extension of Thrombolytic Treatment with Recombinant Streptokinase in Acute Myocardial Infarct in Cuba
Authors: Marrero-Miragaya María ,   The TERIMA Group of Investigators
Published: March 2018

Aim: The extension of recombinant streptokinase (rSK) use in Cuba and to evaluate its effect on in-hospital mortality of patients with acute myocardial infarct (AMI). Methods: A phase IV clinical study was performed in 52 hospitals from the 14 Cuban provinces. Patients (any age) with ST segment elevation or bundle branch block were included if they came less than 12 h after the onset of AMI symptoms, without contraindications for thrombolytic therapy. They received 1.5 × 106 IU of rSK (Heberkinasa, Heberbiotec, Havana) intravenously, during one hour. Endpoints were death due to cardiac (pump failure, wall rupture, arrhythmia) or any cause and cardiovascular events at hospital release. Results: The study included 2923 patients, 22 – 98 years-old, 74.4% men, which represented 37.2% of the total AMI patients attended at the participating hospitals from November 1992 to May 1995. Aspirin was given to 92.5% and betablockers to 65.3%. AMI was confirmed in 93.5% of the patients. The mean symptoms – rSK infusion time interval was 5.25 h (22.3% of the patients treated within the first 3 h). 302 patients died, 80.1% of them due to cardiac causes, 12 attributed to rSK treatment, and 16 to non-cardiac causes. This 10.4% mortality represents a 4% absolute and a 28.3% relative reduction (179 lives saved per year) as compared to a survey made before rSK treatment was introduced. In a logistic regression analysis, mortality was favored by age, symptoms – infusion time, Killip class, and not having taken aspirin or betablockers. Feminine gender was close to the limit of significance. The more frequent adverse events were arrhythmias and hypotension during infusion. Major bleeding occurred in 27 patients (9 strokes). Conclusion: Local recombinant-DNA biotechnology can influence on a major health problem with favorable cost/ and risk/ benefit balances, not possible in a developing country with an imported drug. The further extension of this treatment in the country is feasible and recommended, monitored through an appropriate pharmacosurveillance program.
Short-term Prognostic Value of Lipid Measurements in Patients with Angina pectoris
Authors: Bolibar Ignasi , Assmann Gerd , Thompson Simon , von Eckardstein Arnold ,   The ECAT Angina Pectoris Study Group
Published: March 2018

We studied the role of various markers of lipid metabolism, hemostasis and inflammation in a two year follow-up of 3000 patients with angina pectoris, during which time 106 patients experienced myocardial infarction or sudden coronary death. Low levels of high density lipoprotein (HDL) cholesterol and of apolipoprotein (apo) A-I were most strongly associated with increased coronary risk. The relative risk per standard deviation increase was 0.68 for HDL cholesterol (95% confidence interval 0.55 to 0.84) and 0.66 for apoA-I (0.54 to 0.81). These associations were independent of other coronary risk factors, other lipid measurements, hemostatic factors, and C-reactive protein (CRP). The associations of total and LDL cholesterol, triglycerides, apoB, and lipoprotein(a) with coronary events were not independent of HDL cholesterol or hemostatic factors. We conclude that HDL cholesterol or apoA-I, hemostatic risk factors, and CRP are important prognostic markers of coronary events in secondary prevention.
Unopposed Estrogen Increases Total Plasma Factor VII, but not Active Factor VII
Authors: de Valk-de Roo Gerdien , Emeis Jef , Nicolaas-Merkus Ans , Netelenbos Coen , Stehouwer Coen D.
Published: March 2018

Estrogen therapy may increase the risk of arterial thromboembolism, at least in the short term. In a randomized, double-blind and placebocontrolled study in 25 healthy postmenopausal women (52.5 ± 2.8 years), we therefore examined the short-term effect of unopposed estrogen on the fasting and fat-load-stimulated plasma levels of total factor VII versus active factor VII. Plasma total factor VII was measured by use of a chromogenic assay; plasma active FVII by a recently developed method using truncated tissue factor. As compared to placebo, 8 weeks of oral 17β-estradiol (2 mg daily) increased the mean fasting and postprandial plasma levels of total factor VII by 17 and 21% points, respectively (both P < 0.01), but did not affect the fasting and/or postprandial plasma levels of active factor VII (mean change both 0.05 ng/mL; P > 0.35). Furthermore, the change in the fasting level of total factor VII after therapy was not associated with the change in the fasting level of active factor VII (r = 0.27; P = 0.21). These findings argue against the idea that elevated levels of total factor VII underlie an increased risk of arterial thromboembolism in postmenopausal women using unopposed estrogen replacement.
Compression Ultrasonography of the Leg Veins in Patients with Clinically Suspected Pulmonary Embolism
Authors: Sanson Bernd-Jan , Büller Harry , Brandjes Dees P. , Mac Gillavry Melvin ,   the ANTELOPE-Study Group
Published: March 2018

We performed a multi-center study in consecutive patients with suspected pulmonary embolism to compare the diagnostic accuracy of a two-point compression ultrasonography (only the common femoral vein and popliteal vein) with an extensive examination of compressibility (from the common femoral vein until the trifurcation of calf veins). A total of 479 patients underwent the two-point compression ultrasonography. The prevalence of pulmonary embolism was 32%. The sensitivity and specificity of this procedure were 23% (95% CI 19-26) and 98% (95% CI 96-99), respectively. Extensive compression ultrasonography was performed in 461 (96%) of these 479 patients and showed comparable accuracy indices (sensitivity 25%, 95% CI 20-28 and specificity 97%, 95% CI 95-99). We conclude that compression ultrasonography has a limited sensitivity for the detection of thrombosis in patients with acute pulmonary embolism within 24 h of presentation. A more extensive assessment of compressibility of the leg veins in these patients has no additional value as compared to the two-point assessment.
Endogenous Clotting Factor Activity and Long-term Outcome in Patients with Moderate Haemophilia
Authors: van der Bom J. G. , Mauser-Bunschoten E. P. , Roosendaal G. , Beek F. J. A. , de Kleijn P. , Grobbee D. E. , van den Berg H. M. , Fischer K.
Published: March 2018

In order to address the question of the optimum target level for prophylactic treatment of severe haemophilia patients, the association between endogenous clotting factor activity and outcome was studied in a cohort of 46 patients with moderate haemophilia. Data on treatment and outcome were collected annually.

Median follow-up was 8.0 years (range 1-26). Median joint bleed frequency was 1 per year and median radiological score according to Pettersson was 1 point (max. 78) at the age of 25 years. One percent increase in clotting factor level was associated with a 4 months later onset of joint bleeds (95% Confidence Interval (CI): 2-6 months) and a 16% lower Pettersson score (95% CI: 3-27%). No statistically significant effect of clotting factor activity on joint bleed frequency could be demonstrated.

These findings confirm that patients with moderate haemophilia experience only mild arthropathy, and provide evidence for a protective effect of higher clotting factor levels on joint damage.
Epitope Location on Tissue Factor Determines the Anticoagulant Potency of Monoclonal Anti-tissue Factor Antibodies
Authors: Moran Paul , Chiang Nancy , Kim Jin , Riederer Markus , Eigenbrot Charles , Kelley Robert , Kirchhofer Daniel
Published: March 2018

Tissue factor (TF), the cellular cofactor for the serine protease factor VIIa (F. VIIa), triggers blood coagulation and is involved in the pathogenesis of various thrombosis-related disorders. Therefore, agents which specifically target tissue factor, such as monoclonal antibodies, may provide promising new antithrombotic therapy. We mapped the epitopes of several anti-TF antibodies using a panel of soluble TF mutants. They bound to three distinct TF regions. The epitope of the 7G11 antibody included Phe50 and overlapped with a TF-F. VIIa light chain contact area. The common epitope of the antibodies 6B4 and HTF1 included residues Tyr94 and Phe76 both of which make critical contacts to the catalytic domain of F. VIIa. The antibodies D3 and 5G6 had a common epitope outside the TF-F. VIIa contact region. It included residues Lys165, Lys166, Asn199, Arg200 and Lys201 and thus overlapped with the substrate interaction region of tissue factor. The antibodies 5G6 and D3 were potent anticoagulants when infused to flowing human blood in an ex-vivo thrombosis model. Plasma fibrinopeptide A levels and fibrin deposition were completely inhibited. In contrast, 6B4 was a weak inhibitor in this ex-vivo thrombosis model, and HTF1 displayed no inhibition at all. These disparate activities were also reflected in TF-dependent F. X activation assays performed with human plasma. The potency differences could neither be explained by the determined binding affinities nor by the on-rates of antibodies. Therefore, the results suggest that antibody binding epitope and hence the particular mechanism of inhibition, is the main determinative factor of anticoagulant potency of anti-TF antibodies.
Occurrence of Amphoterin (HMG1) as an Endogenous Protein of Human Platelets that Is Exported to the Cell Surface upon Platelet Activation
Authors: Imai Shinji , Rauvala Heikki , Parkkinen Jaakko , Rouhiainen Ari
Published: March 2018

Amphoterin (HMG1) is a 30-kD heparin-binding protein which is functionally associated with the outgrowth of cytoplasmic processes in developing neurones. Amphoterin has been shown to mediate adhesive and proteolytic interactions at the leading edge of motile cells. Recently it was shown that inhibition of amphoterin interactions with its cell surface receptor (RAGE) suppresses tumour growth and metastasis. In this work we have identified amphoterin polypeptide and its mRNA in human platelets. Amphoterin had a cytoplasmic localisation in resting platelets according to subcellular fractionation studies and immunogold electronmicroscopy. After platelet activation, part of amphoterin was associated with the external surface of plasma membrane. Externalisation of amphoterin during platelet activation was also detected in immunofluorescence studies. Amphoterin was detectable in human serum (0.2 ng/ml) but not in plasma. Resting platelets treated with PGI2 and forskolin bound to immobilised recombinant amphoterin independently of divalent cations. The binding induced a spicular morphology in platelets, and was effectively inhibited by heparin. Amphoterinbinding protein components on the platelet surface were not identified, but amphoterin bound to phosphatidylserine and sulfatide in lipid binding assays. Our results suggest that amphoterin is an endogenous protein in human platelets, which is exported to the cell surface during platelet activation. Interaction of amphoterin with the platelet surface may be mediated by sulfoglycolipids and phospholipids.
Effect of Sodium Arachidonate on Thrombin Generation through Platelet Activation – Inhibitory Effect of Aspirin
Authors: Scazziota Alejandra , Rouvier Jorge , Gonzalez Claudio , Altman Raul
Published: March 2018

Background. Sodium arachidonate was used in this study to determine its capacity to generate thrombin through platelet activation. Whether aspirin prevent this effect was also investigated. Methods and Results. Seventeen healthy volunteers without and after 160 mg/day aspirin intake for 3-5 days were studied. Lag-time and TG at basal condition and after platelet stimulation by sodium arachidonate (AA) were measured in normal non-aspirinated as well as “in vivo” aspirinated platelet rich plasma. (PRP). The lag-time was statistically significant shorter in non-aspirinated PRP activated with AA compared with non-activated PRP. This effect was inhibited by aspirin. In non-aspirinated PRP, there was an increase of TG at 4 and 6 min. incubation when platelets were activated with AA but the difference disappeared after 8 min. incubation, (84 ± 71; 148 ± 58 and 142 ± 92 nmol/L respectively) compared with non-aspirinated, non-activated platelets (16 ± 23; 55 ± 56 and 111 ± 76 nmol/L at 4, 6 and 8 min, p < 0.0001, p < 0.0001 and p = 0.292, respectively). The AUCo→22 min were 520.6 ± 545.5 in nonaspirinated, non-stimulated PRP and 808.9 ± 617, in non-aspirinated PRP activated with sodium arachidonate (p = 0.014). Aspirin administered in vivo produced a decrease of TG in PRP activated with AA.

Conclusion. Platelet activated by AA trigged TG. This effect was inhibited by aspirin and could be an additional beneficial effect of aspirin in the prevention of thrombosis.
Genetic Risk Factors for Superficial Vein Thrombosis
Authors: Cattaneo Marco , Taioli Emanuela , De Stefano Valerio , Chiusolo Patrizia , Mannucci Pier Mannuccio , Martinelli Ida
Published: March 2018

Inherited thrombophilic states are associated with an increased risk for deep vein thrombosis (DVT), but whether they are also risk factors for superficial vein thrombosis (SVT) is uncertain. We assessed the risk conferred by inherited thrombophilic states in patients with a first episode of SVT in whom the coexistence of DVT had been ruled out by ultrasonography. Sixty-three patients with SVT, after exclusion of patients with varicose veins, malignant or autoimmune disease, and 537 healthy individuals were investigated. The G1691A mutation in the factor V gene, the G20210A mutation in the prothrombin gene, and deficiencies of the naturally occurring inhibitors of coagulation (antithrombin, protein C, protein S) were searched. The prevalence of each thrombophilic state was higher in patients than in controls. The odds ratios for SVT were 6.1 (95% confidence interval [CI], 2.6 to 14.2) in patients with the G1691A factor V mutation, 4.3 (95% CI, 1.5 to 12.6) in those with the G20210A prothrombin mutation, and 12.9 (95% CI, 3.6 to 46.2) in those with deficiencies of the naturally occurring inhibitors of coagulation taken together. Risks did not substantially change when the analysis was restricted to 43 patients who had SVT as their only thrombotic manifestation, being 4.3 (95% CI, 1.5 to 12.3) in patients with factor V mutation, and 3.6 (95% CI, 1.0 to 13.1) in those with the prothrombin mutation. Among the circumstantial risk factors investigated (surgery, trauma, prolonged immobilization, oral contraceptives and pregnancy or puerperium), pregnancy or puerperium was the most frequently associated with SVT, being present in 38% of women. Our findings indicate that inherited thrombophilic states are associated with an increased risk for SVT. Hence, a laboratory search of these alterations is recommended in patients with SVT, because it allows the identification of patients at high risk of DVT in whom antithrombotic prophylaxis is particularly warranted.
Prospective Evaluation of Hemostatic System Activation and Thrombin Potential in Healthy Pregnant Women with and without Factor V Leiden
Authors: Weltermann Ansgar , Philipp Karl , Hafner Erich , Kaider Alexandra , Kittl Eva-Maria , Brenner Brigitte , Mannhalter Christine , Lechner Klaus , Kyrle Paul , Eichinger Sabine
Published: March 2018

Normal pregnancy is associated with alterations of the hemostatic system towards a hypercoagulable state and an increased risk of venous thromboembolism. The risk of venous thrombosis is higher in pregnant women with factor V Leiden (FVL) than in those with wildtype factor V. Routine laboratory assays are not useful to detect hypercoagulable conditions. A prospective and systematic evaluation of hemostatic system activation in women with and without FVL during an uncomplicated pregnancy employing more sensitive markers of hypercoagulability, such as prothrombin fragment 1+2 (F1+2), thrombin-antithrombin complex (TAT), D-Dimer, or the endogenous thrombin potential (ETP), an indicator of the plasma’s potential to generate thrombin, has not been performed. We prospectively followed 113 pregnant women with (n = 11) and without (n = 102) FVL and measured F1+2, TAT, D-Dimer and the ETP at the 12th, 22nd and 34th gestational week as well as 3 months after delivery (baseline) in each subject. None of the women developed clinical signs of venous thromboembolism during pregnancy or postpartum. Pregnant women with and without FVL exhibited substantial activation of the coagulation and fibrinolytic system as indicated by a gradual increase of F1+2, TAT and D-Dimer throughout uncomplicated pregnancy up to levels similar to those found in acute thromboembolic events (p < 0.0001 by analysis of variance for each parameters). Levels of F1+2 and TAT were comparable between women with and without FVL, but levels of D-Dimer were significantly higher in women with FVL than in those without the mutation (p = 0.0005). The ETP remained unchanged in both women with and without FVL at all timepoints. Our data demonstrate a substantial coagulation and fibrinolytic system activation in healthy women with and without FVL during uncomplicated pregnancy. An elevated F1+2, TAT or D-Dimer level during pregnancy is not necessarily indicative for an acute thromboembolic event. The normal ETP in both women with and without FVL suggests that the capacity of the plasma to generate thrombin after in vitro activation of the clotting system is not affected by pregnancy. Higher levels of D-Dimer in women with FVL than in women with wildtype factor V at baseline as well as during pregnancy indicate increased fibrinolytic system activation in carriers of the mutation.
A Flow Cytometric Assay of Platelet Activation Marker P-Selectin (CD62P) Distinguishes Heparin-induced Thrombocytopenia (HIT) from HIT with Thrombosis (HITT)
Authors: Jy Wenche , Mao Wei Wei , Horstman Lawrence , Valant Peter , Ahn Yeon
Published: March 2018

Heparin induced thrombocytopenia (HIT) is a well-known complication of heparin administration but usually resolves upon discontinuation without sequelae. However, a small proportion of HIT patients develop thrombosis associated with HIT, designated as HITT, which is often life-threatening and may lead to gangrene and amputations. Existing laboratory methods of confirming HIT/HITT do not distinguish between HIT and HITT. We report a flow cytometric assay of platelet activation marker CD62P to distinguish the effects of addition of HIT vs. HITT plasma to normal blood. Briefly, normal whole blood was incubated with platelet-poor plasma from 12 patients with HITT, 30 with HIT, and 65 controls, in presence and absence of heparin, and expression of CD62P was assayed by flow cytometry. When the ratios of fluorescent intensity of CD62P with heparin divided by that without heparin were compared, HITT plasma induced significantly higher ratios than HIT plasma (HITT ratios ~2.5 vs. HIT ratios ~1.2; p <0.001). Eleven of 12 HITT patients were positive by this test but only 5 of 30 HIT patients were positive (p < 0.0005). In a case of HIT with silent thrombosis, this assay gave a positive results prior to clinically evident thrombosis. In conclusion, this method distinguishes HITT from HIT and may be clinically useful in the detection of HITT, allowing early intervention for preventing catastrophic thrombosis.
Platelet Aging In Vivo Is Associated with Loss of Membrane Phospholipid Asymmetry
Authors: Palomo Iván , Ocqueteau Mauricio , Soto Mónica , Aranda Eduardo , Mezzano Diego , Pereira Jaime
Published: March 2018

The mechanism(s) involved in the clearance of senescent platelets are largely unknown. The loss of membrane phospholipid (PL) asymmetry, with phosphatidylserine (PS) exposure appears to be an important signal for the ingestion by macrophages of apoptotic nucleated cells and it has also been suggested as a signal for the removal of aged erythrocytes. Accordingly, it seems possible that the clearance of normal aged platelets from circulation might be triggered by PS exposure. To investigate this, we determined PS exposure in human aging platelets taking advantage of the relationship between platelet density and platelet age and in dog platelets in a model of platelet aging in vivo. PS exposure was determined in two experimental conditions: 1) human platelet density subpopulations obtained by centrifugation in arabinogalactan gradients; 2) circulating canine platelets during decline in platelet count after suppression of thrombopoiesis following estradiol injection. PS exposure was determined by flow cytometry after labeling the cells with FITC-conjugated annexin V. The proportion of human platelets with exposed PS was significantly higher in high density (HD) platelets compared to low density (LD) platelets (11.3 ± 8.0% vs 5.2 ± 3.7%; p <0.05, respectively). In dogs, the proportion of cells with exposed PS rises dramatically with age, from 3.1 ± 0.4% before to 17.7 ± 12.3% ten days after estradiol injection. These findings suggest that platelet aging is associated with loss of phospholipid asymmetry and PS exposure on the outer leaflet of cell membrane, which may play an important role in the recognition and subsequent removal of senescent platelets.