bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sensitivity to Activated Protein C; Influence of Oral Contraceptives and Sex
Authors: Henkens C M A , Bom V J J , Seinen A J , van der Meer J 
Published: July 2018

SummaryWe investigated sensitivity to activated protein C (APC) in 43 men, 42 women not using oral contraceptives (OC) and 38 women using OC containing 30.0-37.5 μg ethinyl estradiol. A commercially available kit was used. Men were more sensitive to APC as compared with women not using OC (p <0.005), but this difference seems not to be of clinical importance. Women using OC showed to be significantly less sensitive to APC, reflected by a lower APC-ratio, as compared with men (p <0.005) and women not using OC (p <0.05).So, in normal individuals the APC-sensitivity differs according to sex and estrogen intake. This should be taken into account when interpreting APC-ratios.
Glycoprotein IIb/IIIa Blockade Inhibits Platelet-mediated Force Development and Reduces Gel Elastic Modulus
Authors: Carr Marcus E , Carr Sheryl L , Hantgan Roy R , Braaten Julie 
Published: July 2018

SummaryThe effects of GPIIb/IIIa blockade on clot retraction were studied utilizing an instrument which directly measures force produced by platelets. GPIIb/IIIa disruption by calcium chelation, and GPIIb/IIIa blockade by peptides and anti-GPIIb/IIIa antibodies were investigated. One mM EDTA suppressed ADP-induced platelet aggregation by 72% and reduced force developed at 1200 s by 33%. At 234 μM, the tetrapeptide Arg-Gly-Asp-Ser (RGDS) suppressed platelet aggregation by 74%, reduced force at 1200 s by 45% and reduced gel elastic modulus by 19%. At 10 μM, the peptide D-Arg-Gly-L-Asp-L-Try (D-RGDW) completely suppressed platelet aggregation, reduced force development by 38% and reduced gel elastic modulus by 29%. At 0.133 μM, monoclonal anti-GPIIIa antibody (AP-3) reduced force development by 74% and reduced gel modulus by 60%. Murine antiGPIIb/IIIa antibodies 10E5 and 7E3 markedly suppressed force development. At 0.133 μM, 10E5 reduced force by 89% and reduced gel modulus by 67%. At 0.053 μM, 7E3 completely stopped force development and reduced gel modulus by 46%. Platelet aggregation was blocked by 0.027 μM 7E3. Selective GPIIb blockade by antibodies did not affect force development. None of the agents studied altered fibrin structure as monitored by effects on fibrin mass/length ratios. Suppression of platelet aggregation occurred at inhibitor concentrations substantially lower than those required to suppress force development. Complete suppression of platelet aggregation did not assure inhibition of clot retraction probably due to profound platelet activation by thrombin. These results indicate that inhibition of fibrin(ogen) binding to GPIIb/IIIa, either by disruption of GPIIb/IIIa or by competitive blockade, inhibits platelet mediated force development and results in clot structures which are substantially less resistant to deformation by outside forces.
Anticoagulant-induced Pseudothrombocytopenia and Pseudoleucocytosis
Authors: Schrezenmeier Hubert , Müller Hilke , Gunsilius Eberhard , Heimpel Hermann , Seifried Erhard 
Published: July 2018

SummaryPseudothrombocytopenia (PTP) is the phenomenon of falsely low platelet counts due to in vitro platelet clumping in the presence of platelet autoantibodies and anticoagulants. We assessed anticoagulant- dependence, time course of platelet counts and impact of different counter devices on the phenomenon. Blood of 10 persons with previously recognized pronounced EDTA-dependent PTP was collected into 7 different anticoagulants and counted after different intervals in parallel in a Coulter T540 and a Coulter STKS counter and by phase contrast microscopy. With the Coulter T540 model PTP was most pronounced in blood samples anticoagulated with EDTA, Na-oxalate or Na-citrate. In the STKS counter EDTA, heparin and oxalate presented as the worst anticoagulants. The time course of platelet counts was significantly different between the two counters. Our results demonstrate that PTP is not restricted to EDTA, but is also present with other anticoagulants. In contrast, pseudoleucocytosis was observed only in EDTA-anticoagulated blood in the Coulter T540 device.We investigated the expression of platelet integrins and activation antigens on platelets of persons with anticoagulant-dependent PTP and in healthy controls without PTP. In the presence of EDTA the expression of GpIIb/IIIa was significantly reduced in the PTP subjects compared to control. Activation antigens CD62, CD63 and thrombospondin-antigen were upregulated in the presence of EDTA. These alterations in the expression of platelet antigens could also be induced on platelets of normal donors by incubation with sera of PTP subjects and EDTA. The downregulation of GP IIb/IIIa in EDTA-blood of PTP subjects supports the hypothesis that the GPIIb/IIIa complex might be the binding site for the anti-platelet antibodies present in the sera of PTP subjects. Our results suggest that the binding of the autoantibodies causes platelet activation similar to other platelet-activating stimuli leading to subsequent platelet agglutination.
Arg506GIn Factor V Mutation (Factor V Leiden) in Patients with Ischaemic Cerebrovascular Disease and Survivors of Myocardial Infarction
Authors: Kontula Kimmo , Ylikorkala Antti , Miettinen Helena , Vuorio Alpo , Kauppinen-Mäkelin Ritva , Hämäläinen Liisa , Palomäki Heikki , Kaste Markku 
Published: July 2018

SummaryThe point mutation Arg506->Gln of factor V was recently shown to be an important and relatively common genetic cause of venous thromboembolism. Using a DNA technique based on polymerase chain reaction, we surveyed the blood samples of 236 patients with ischaemic stroke or a transient ischaemic attack, 122 survivors of myocardial infarction and 137 control subjects for the presence of this mutation. Although the frequency of the factor V mutation in patients with arterial disease (4.5%) was not significantly different from that in healthy blood donors (2.9%), a carrier status for this mutant gene was associated with symptoms of migraine and relatively mild angiographic abnormalities among patients with cerebrovascular disease. A more extensive study addressing the occurrence and significance of the mutant factor V mutation in patients with vasospastic cerebrovascular diseases seems to be warranted.
Raised Plasma Fibrinogen Concentrations in Subjects Attending a Metabolic Ward - Relation to Family History and Vascular Risk Factors
Authors: Margaglione Maurizio , Di Minno Giovanni , Grondone Elvira , Vecchione Gennaro , Celentano Egidio , Cappucci Giuseppe , Giordano Mauro , Grilli Massimo , Simone Pasquale , Fusilli Saverio , Panico Salvatore , Mancini Mario 
Published: July 2018

SummaryWe have evaluated plasma fibrinogen levels in 171 subjects attending a metabolic ward. As in the general population, a significant difference in plasma fibrinogen concentrations (p <0.05) was found between subjects with diabetes mellitus or hypertension and those without. However, fibrinogen was also abnormally high (p <0.05) when evaluated according to the presence of a family history of ischemic complications of atherosclerosis (p <0.05). In this setting, fibrinogen correlated with diabetes mellitus or hypertension as well as with familial risk, and the latter interacted with hypertension (p <0.05) in accounting for plasma fibrinogen.The relationships between certain fibrinogen genotypes and familial risk have then been evaluated. Analysis of a locus (1.3 kb, HAE III digestion) of the promoter region of the BB fibrinogen gene, identified a polymorphic cutting site. The allele with the alternative restriction site (HI) was associated with mean fibrinogen levels which were 0.1-0.3 g/1 lower than those associated with the other allele (H2). This difference was not statistically significant. No obvious association was found between the familial risk and the presence of the H2 allele. We conclude that in a group of subjects from a metabolic ward, a positive family history for ischemic complications of atherosclerosis is consistently associated with high plasma fibrinogen levels. Interaction with hypertension significantly strengthens the association.
Variability of In Vivo Recovery of Factor IX after Infusion of Monoclonal Antibody Purified Factor IX Concentrates in Patients with Hemophilia B
Authors: White Gilbert C , Shapiro Amy D , Kurczynski Elizabeth M , Kim Hugh C , Bergman Garrett E ,   Mononine® Study Group
Published: July 2018

SummaryMonoclonal antibody purified factor IX concentrate, Mononine® (Armour Pharmaceutical Company, Kankakee, Illinois, USA), is a recently developed replacement factor concentrate for the treatment of patients with hemophilia B. The pharmacokinetic properties of monoclonal antibody purified factor IX concentrate (MAb Factor IX concentrate) have been evaluated in only small samples of patients, and little is known about those factors that might influence in vivo recovery of factor IX after infusion in a larger patient population. In vivo recovery of factor IX was therefore evaluated for 80 different indications in 72 patients who received MAb Factor IX concentrate for the management of spontaneous or trauma-induced bleeding, or as prophylaxis with surgery. The average recovery after infusions for presurgical pharmacokinetic analysis (mean ± standard deviation) was 1.28 ± 0.56 U/dl rise per U/kg infused (range 0.41-2.80), and the average recovery after all infusions for treatment was 1.23 ± 0.49 U/dl rise per U/kg infused (range -0.35-2.92). Recovery values for multiple MAb Factor IX doses in a given patient were also variable; the average recovery was 1.22 ± 0.53 U/dl rise per U/kg given, and standard deviations ranged from 0.03 to 1.26. Patient age, weight, and MAb Factor IX concentrate dose minimally but significantly influenced factor IX recovery. There was no significant effect of either race, history of previous thrombotic complications during treatment with other replacement factor concentrates, or bleeding state on recovery. All of the patients treated with this preparation experienced excellent hemostasis, and no thrombotic complications were observed.
Cellular Localization of Enzymatically Active Thrombin in Intact Human Tissues by Hirudin Binding
Authors: Zacharski Leo R , Memoli Vincent A , Morain William D , Schlaeppi Jean-Marc , Rousseau Sandra M 
Published: July 2018

SummaryCellular sites of coagulation activation within complex, intact tissues have been studied by immunohistochemical techniques. Hirudin, a specific and high affinity inihibitor of the active site of thrombin, together with antibody to hirudin were applied to sections of AMeX-fixed specimens of normal lung, kidney, placenta, freshly incised skin and unperturbed skin obtained at fresh autopsy; to rheumatoid synovial tissue; and to malignant tissue from a variety of tumor types. Staining for thrombin was observed selectively on pulmonary alveolar, rheumatoid synovial, and placental macrophages that express an intact extrinsic coagulation pathway. Staining was also observed restricted to the endothelium of capillaries in freshly incised skin but not in either unperturbed skin or in aged incisions. Staining of tumor cell bodies was observed in small cell carcinoma of the lung, renal cell carcinoma, and malignant melanoma tissues that we found previously to show tumor cell-associated procoagulant activity. This staining occurred commonly on cells within the tumor mass that were distant from stromal fibrinogen/fibrin. By contrast, tumor-associated macrophage but not tumor cell staining was seen in adenocarcinoma and squamous cell carcinoma of the lung, and little or no staining was seen in colon cancer tissue. Negative controls in which either the hirudin probe or its antibody were omitted failed to show staining. These results are in accord with previous findings and suggest that such techniques may be useful for studying the cellular sites of thrombin generation in intact tissues. We postulate that administration of potent and specific thrombin antagonists, such as hirudin, to patients with relevant tumor types might be followed by homing of hirudin to tumor cells in vivo so that effects of local thrombin generation on malignant progression can be determined.
IL-6 Upregulates Protein S Expression in the HepG-2 Hepatoma Cells
Authors: Hooper W Craig , Phillips Donald J , Ribeiro Maria , Benson Jane , Evatt Bruce L 
Published: July 2018

SummarySeveral pro-inflammatory cytokines have been shown to be important in the modulation of the procoagulant response. However, what role these cytokines may have in the regulation of coagulation inhibitors is poorly understood. While the hepatocyte is a primary site of synthesis for the anticoagulant proteins C and S, it is also a major target cell for the proinflammatory cytokine, IL-6. We have found that stimulation of HepG-2 hepatoma cells with IL-6 (5 ng/ml) significantly increased the production of the anticoagulant cofactor, protein S, in both a time and dose dependent fashion. This increase was seen at both the RNA and protein level. A mouse monoclonal neutralizing antibody to human IL-6 suppressed the IL-6 effect in a concentration dependent fashion. IL-6 also increased the release of the C4b-binding protein but had no effect on protein C production. When combined with either dexamethasone or soluble IL-6 receptor, the IL-6 response was significantly enhanced. Oncostatin M, a functionally related cytokine, had a similar effect while other related cytokines, IL-11 and leukemia inhibitory factor, only had a marginal effect. IL-1, TGF-β, and TNF-α had no significant effect on protein S production. These results indicate that IL-6 may play an important regulatory role in the anticoagulant pathway.
Plasminogen Activator Inhibitor Type-1 Determines Plasmin Formation in Patients with Ischaemic Heart Disease
Authors: Pedersen Ole Dyg , Gram Jørgen , Jespersen Jørgen 
Published: July 2018

SummaryThe aim of the present study was to find out whether plasminogen activator inhibitor type-1 (PAI-1) controls the formation of plasmin in patients with ischaemic heart disease.We examined PAI activity, PAI-1 antigen, tissue type plasminogen activator (t-PA) activity, t-PA antigen, plasmin-α2-antiplasmin complex (PAP-complex) and fibrin degradation products D-dimer in 62 patients before (unstimulated) and after infusion of l-desamino-8- D-arginine vasopressin (DDAVP; stimulated). DDAVP was used in a standardized dose to trigger the release of t-PA from the vascular endothelium.We observed that under basal conditions (unstimulated) median plasma t-PA activity for the whole group of patients was 86.5 mlU/ml (0-900), and after stimulation 2550 mlU/ml (0-6800), P <0.0001; median plasma concentration of t-PA antigen was 14.7 ng/ml (7.0-115.5) under basal conditions, and after stimulation 34.1 ng/ml (15.8-58.6), P <0.0001; median plasma PAI activity was 16.9 IU/ml (1.5-144.8) under basal conditions, and after stimulation 3.1 IU/ml (0-118.5), P <0.0001; median plasma concentration of PAI-1 antigen was 21.5 ng/ml (8.1-132.2) under basal conditions, and after stimulation 14.9 ng/ml (4.8-149.0), P <0.0001; the median plasma concentration of PAP-complex was 469.5 ng/ml (185.0-1802.0) under basal conditions, and after stimulation 695.5 (243.0-2292.0), P <0.0001; median plasma concentration of D-dimer was 298.0 ng/ml (103.0-948.0) under basal conditions, and after stimulation 296.5 ng/ml (97.0-917.0), P <0.0008.Under basal conditions plasma PAI activities and plasma concentrations of PAI-1 antigen were both significantly negatively correlated with plasma concentrations of PAP-complex (rs = -0.32; P <0.02 and rs = -0.42; P <0.002, respectively). After stimulation of the fibrinolytic system by infusion of DDAVP, plasma PAI activities and plasma concentrations of PAI-1 antigen were also significantly negatively correlated with plasma concentrations of PAP-complex (rs = -0.41; P <0.002 and rs = - 0.33; P <0.009, respectively).Our results indicate that PAI-1 regulates formation of plasmin in patients with ischaemic heart disease. These observations support that PAI-1 may play a critical role in the evolution of thrombosis.
Enhanced Vascular Plasminogen Activator (t-PA) Release by Epinephrine in Aged Rats
Authors: lacoviello Licia , D’Adamo Maria Cristina , Curtis Amalia De , Buczko Wlodzimierz , Donati Maria Benedetta 
Published: July 2018

SummaryAdrenergic stimulation induces an acute fibrinolytic response in the vascular wall and can play an important role in limiting thrombus growth. The incidence of thrombotic disease increases with age. As many adrenergic functions are affected by aging, the vascular response to adrenergic stimulation was studied in young (3 ± 1 months) and aged (18 ± 3 months) rats, using an experimental model of vascular perfusion. Five min epinephrine (EPI) infusion (0.15-25 μM) induced a dose-dependent increase in tissue-type plasminogen activator (t-PA) release and in perfusion pressure, in both young and aged rats. In the latter, however, the basal activity of t-PA was significantly higher than in young animals (0.22 ± 0.02 vs 0.13 ± 0.01 U/ml; means ± SE; p <0.01, n = 40) and EPI infusion induced a significantly higher increase in t-PA activity (0.78 ± 0.06 vs 0.47 ± 0.08 U/ml, p <0.01, for 6.25 μM EPI). The response was characterized by a delayed onset. In contrast, the increase in the perfusion pressure by EPI was significantly lower in aged that in young rats, its basal levels being normal.To evaluate whether the increased vascular response of t-PA was peculiar for adrenergic stimulation, we infused platelet activating factor (PAF), an inducer of t-PA release, not related to catecholamines. PAF, during five-minute infusion induced a rapid and dose-dependent (100-1250 pM) increase in t-PA release, to the same extent in both young and aged rats.In conclusion, basal t-PA secretion was increased in aged rats probably as a response of vascular endothelium to chronic stimulation. Moreover, the vascular fibrinolytic response to acute EPI stimulation was greater in aging. This response was specific for adrenoceptor stimulation and could represent an adaptative mechanism of adrenergic receptors, counteracting an increased thrombotic tendency.
The Relationship of Venous Diameter to Reflux, Cephalad Thrombus and Cephalad Reflux Following Deep Venous Thrombosis
Authors: Tullis M J , Meissner M H , Bergelin R O , Caps M T , Manzo R A , Strandness D E 
Published: July 2018

SummaryDuplex ultrasonography was used to measure the diameters of the common femoral, superficial femoral and popliteal vein segments in 123 patients following DVT. A cross sectional analysis was done based on the most recent visit to determine chronic venous diameter changes following DVT.Venous diameters in recanalized segments were smaller at all levels compared to those never occluded (p = 0.06 for CFV and p <0.05 for SFV and PV). After accounting for a previous history of occlusion, the diameters of the segments with and without reflux were not significantly different. There was also no evidence of venodilation in segments caudal to cephalad reflux or thrombus.Recanalized veins are smaller in diameter than those which were never thrombosed. Cephalad thrombus or reflux is not associated with venodilatation of caudal segments. Reflux following DVT is probably secondary to valvular damage rather than hypertension, since there was no diameter difference between refluxing and non-refluxing segments.
Inhibition of Urokinase-type Plasminogen Activator (uPA) Abrogates Myogenesis In Vitro
Authors: Muñoz-Cánoves Pura , Miralles Francesc , Baiget Montserrat , Félez Jordi 
Published: July 2018

SummaryUrokinase-type plasminogen activator (uPA) is one of the components of blood’s fibrinolytic cascade. uPA acts as a broad spectrum proteolytic enzyme involved in different physio-pathological processes including cellular fibrinolysis, adhesion, migration, invasion and remodeling. Here, we present evidence that uPA participates in myogenesis, a process which requires drastic cell membrane reorganization, leading to the plurinucleated myotube from the progenitor myoblast. We have dissected the expression of uPA throughout the different myogenic compartments and found an increase in uPA enzymatic activity associated with myotube formation in C2C12 myoblast cells, with uPA mRNA increasing prior the onset of fusion and differentiation. When both fusion and differentiation were blocked by specific inhibitors (DMSO, cyto-chalasin B) the levels of uPA were strongly downregulated. This process was reversible and specific: the removal of the inhibitors immediately restored the levels of uPA mRNA while the specific inhibition of uPA enzymatic activity by an anti-uPA antibody resulted in a 50% reduction of the extent of fusion and in the abrogation of muscle-specific gene products, such as a-actin and MyoD. Moreover, the conversion of fibroblasts to muscle-like cells upon acquisition of MyoD resulted in a dramatic increase of uPA mRNA, which was partially due to transcriptional activation of the uPA gene. These results indicate that the increase in uPA expression prior to fusion and differentiation occurs via a MyoD-mediated mechanism whereas the normal MyoD expression requires the plasminogen activation-dependent activity of this protease. Therefore, these studies extend the sphere of influence of myogenic factors to fibrinolysis, an intrinsic component of the hematological system. Taken together, one mechanism used by the myoblast cell to become a differentiated myotube, involving the inductive extracellular proteolysis of urokinase, is proposed.
Ganglioside Content of Human Platelets – Differences in Resting and Activated Platelets
Authors: Ferroni Patrizia , Lenti Luisa , Martini Francesca , Ciatti Filippo , Pontieri Giuseppe M , Gazzaniga Pier Paolo 
Published: July 2018

SummaryGangliosides may play functional roles in platelet physiology, therefore this study has been designed to evaluate whether changes in ganglioside composition may occur as a consequence of platelet activation. The results obtained indicate that lactosylceramide and GM3 are the major glycosphingolipids of human platelets. The lipid-bound sialic acid (LBS A) content was 1.27 ± 0.04µεg/mg of protein. Resting platelets did not express GD3; GD3 was synthesized upon platelet activation (24 ± 8 ng/mg of protein). The stimulation of platelets with adenosine diphosphate showed the appearance of GD3 even in the absence of degranulation. Finally, incorporation of pyrene-labeled GM3 into platelet membranes, followed by stimulation with adenosine diphosphate, resulted in the appearance of a fluorescent band comigrating with GD3. The present studies indicate that sialyltransferase activation may occur as an early event following platelet stimulation, leading to GD3 synthesis mainly from the GM3 pool.
The Routine Determination of the Endogenous Thrombin Potential, First Results in Different Forms of Hyper- and Hypocoagulability
Authors: Wielders Simone , Mukherjee Manjari , Michiels Jan , Rijkers Dirk T S , Cambus Jean-Pierre , Knebel Richard W C , Kakkar Vijay , Hemker H Coenraad , Béguin Suzette 
Published: July 2018

SummaryThe area under the thrombin generation curve (the endogenous thrombin potential; ETP) has been proposed as a parameter for plasma-based hypercoagulability and to monitor anticoagulant treatment. We present an ETP assay for the routine laboratory using a centrifugal analyser. Throughput is 30 samples/h, within and between run imprecision is 4-5.6%. Suitable substrates were developed for the ranges of 10-500% and 2-100% of normal.Independent of tissue factor concentration (if >4 pM), the normal value of the extrinsic ETP is 384.8 ±51.7 nM.min. The intrinsic ETP, triggered by ellagic acid, is 414 ± 41 nM.min.The ETP is decreased to 15 and 35% of normal by oral anticoagulation (INR 2.5-4.0) and by heparin administration (APTT 1.5-2.5 X control).The ETP is increased in untreated subjects with congenital antithrombin deficiency and in women using oral contraceptives. In deep vein thrombosis (phlebographically confirmed), it is increased by 29.4% (extrinsic) and 53% (intrinsic). In (angiographically assessed) coronary artery disease the increase is by 10% and 17% respectively.