bluuebunny/crossref_metadata_2025 huggingface dataset:
Precise manipulation of the carrier recombination zone: a universal novel device structure for highly efficient monochrome and white phosphorescent organic light-emitting diodes with extremely small efficiency roll-off
Authors: Miao Yanqin , Wang Kexiang , Gao Long , Zhao Bo , Wang Hua , Zhu Furong , Xu Bingshe , Ma Dongge
Published: July 2018

The OLEDs, having mixed hosts sandwiched between hole- and electron-transporting hosts, exhibit an EQE exceeding the theoretical limit and extremely small efficiency roll-off.
Monolayer GeS as a potential candidate for NO2 gas sensors and capturers
Authors: Ma Shuhong , Yuan Dongyu , Wang Yiran , Jiao Zhaoyong
Published: July 2018

A GeS monolayer serves as an optimal NO2 gas sensor and capturer even in background water and oxygen.
Ultra-stretchable, sensitive and durable strain sensors based on polydopamine encapsulated carbon nanotubes/elastic bands
Authors: Wang Yalong , Jia Yanyan , Zhou Yujie , Wang Yan , Zheng Guoqiang , Dai Kun , Liu Chuntai , Shen Changyu
Published: July 2018

A polydopamine (PDA)/carbon nanotube (CNT)/elastic band (EB) flexible strain sensor has desirable integration of an ultra-high strain range (920% strain), large sensitivity and superior durability (10 000 cycles).
Rapid macroscale shape morphing of 3D-printed polyrotaxane monoliths amplified from pH-controlled nanoscale ring motions
Authors: Lin Qianming , Li Longyu , Tang Miao , Hou Xisen , Ke Chenfeng
Published: July 2018

Controlling ring motions in a polyrotaxane-based 3D-printed monolith by pH variation results in a rapid and reversible macroscale shape morphing.
In vitro modulation of mercury-induced rat liver mitochondria dysfunction
Authors: Ma Long , Bi Kai-Dong , Fan Yu-Meng , Jiang Zi-Yi , Zhang Xiao-Yi , Zhang Jing-Wen , Zhao Jie , Jiang Feng-Lei , Dong Jia-Xin
Published: July 2018

Multiple methods are employed to reveal the effects of mercury(II) ions and mechanisms of dysfunction caused by them on isolated mitochondria.
Emission of solar chromospheric and transition region features related to the underlying magnetic field
Authors: Barczynski K. , Peter H. , Chitta L. P. , Solanki S. K.
Published: July 2018

Context. The emission of the upper atmosphere of the Sun is closely related to magnetic field concentrations at the solar surface.

Aims. It is well established that this relation between chromospheric emission and magnetic field is nonlinear. Here we investigate systematically how this relation, characterised by the exponent of a power-law fit, changes through the atmosphere, from the upper photosphere through the temperature minimum region and chromosphere to the transition region.

Methods. We used spectral maps from the Interface Region Imaging Spectrograph (IRIS) covering Mg II and its wings, C II, and Si IV together with magnetograms and UV continuum images from the Solar Dynamics Observatory. After a careful alignment of the data we performed a power-law fit for the relation between each pair of observables and determine the power-law index (or exponent) for these. This was done for different spatial resolutions and different features on the Sun.

Results. While the correlation between emission and magnetic field drops monotonically with temperature, the power-law index shows a hockey-stick-type variation: from the upper photosphere to the temperature-minimum it drops sharply and then increases through the chromosphere into the transition region. This is even seen through the features of the Mg II line, this is, from k1 to k2 and k3. It is irrespective of spatial resolution or whether we investigate active regions, plage areas, quiet Sun, or coronal holes.

Conclusions. In accordance with the general picture of flux–flux relations from the chromosphere to the corona, above the temperature minimum the sensitivity of the emission to the plasma heating increases with temperature. Below the temperature minimum a different mechanism has to govern the opposite trend of the power-law index with temperature. We suggest four possibilities, in other words, a geometric effect of expanding flux tubes filling the available chromospheric volume, the height of formation of the emitted radiation, the dependence on wavelength of the intensity-temperature relationship, and the dependence of the heating of flux tubes on the magnetic flux density.
Gangless cross-evaluation in DEA: an application to stock selection
Authors: Amin Gholam R. , Oukil Amar
Published: July 2018

This paper discusses the impact of ganging decision making units (DMUs) on the cross-efficiency evaluation in data envelopment analysis (DEA). A group of DMUs are said to be ganging-together if the minimum and the maximum cross-efficiency scores they give to all other DMUs are identical. This study demonstrates that the ganging phenomenon can significantly influence the cross-efficiency evaluation in favour of some DMUs. To overcome this shortcoming, we propose a gangless cross-efficiency evaluation approach. The suggested method reduces the effect of ganging and generates a more diversified list of top performing units. An application to the Tehran stock market is used to show the benefits of gangless cross-evaluation.
Thyroid Autoantibodies do not Impair the Ovarian Reserve in Euthyroid Infertile Women: A Cross-Sectional Study
Authors: Osuka Satoko , Iwase Akira , Goto Maki , Takikawa Sachiko , Nakamura Tomoko , Murase Tomohiko , Kato Nao , Kotani Tomomi , Kikkawa Fumitaka ,   Bayasula
Published: July 2018

Patients with primary ovarian insufficiency (POI) have a high prevalence of thyroid autoimmune disorders. However, the extent of the contribution of thyroid autoantibodies or elevated thyroid-stimulating hormone (TSH) levels to decreased ovarian reserve is unclear. Therefore, we evaluated the serum levels of anti-Müllerian hormone (AMH) and thyroid autoantibodies [antithyroperoxidase antibody (TPOAb), and antithyroglobulin antibody (TgAb)] in euthyroid infertile women. One hundred and fifty-three women with normal menstrual cycles were recruited for this retrospective study. Serum levels of AMH were compared between patients with positive and negative thyroid autoantibodies. The correlation between serum levels of AMH and each thyroid autoantibody was also evaluated. Participants were observed to be either TPOAb or TgAb positive (n=27), only TPOAb positive (n=8), only TgAb positive (n=7), TPOAb and TgAb positive (double positive; n=12), and TPOAb and TgAb negative (double negative; n=126). No significant differences were found in serum AMH levels between the TPOAb- or TgAb-positive women and the antibody-double negative women. Serum AMH levels did not show a significant correlation with the concentration of TgAb or TPOAb. On the other hand, serum AMH levels negatively correlated with TSH levels in patients who were either positive for TPOAb or TgAb. Thyroid autoantibodies are not likely to influence ovarian reserve in euthyroid women whose TSH levels fall within the normal range although elevated TSH levels may be involved in the decline of serum AMH levels.
Einfluss einer strukturierten Nachsorge auf die
Therapietreue bei OSAS-Patienten unter CPAP-Therapie
Authors: Ritter Julia , Geißler Katharina , Schneider Gerlind , Guntinas-Lichius Orlando
Published: July 2018

Hintergrund Die Therapie mit CPAP (continuous positive airway pressure
therapy) ist die Referenztherapie beim mittel- und hochgradigen obstruktiven
Schlafapnoesyndrom (OSAS). Die Therapietreue bei diesem Verfahren ist jedoch
nicht zufriedenstellend. Ziel der Untersuchung war die Analyse der
Einflussfaktoren auf die Therapietreue sowie die Evaluation, ob eine
strukturierte Nachsorge die Therapietreue verbessert.

Material und Methoden In dieser Studie wurden alle Patienten (n = 237) mit
der Diagnose eines milden bis schweren OSAS und einer neu angepassten
CPAP-Therapie im Zeitraum zwischen 2011 und 2013 untersucht. Die
Nachsorgetermine fanden alle 1593,7 ± 77,4 CPAP-Betriebsstunden statt.

Ergebnisse Unter Therapie nahm der AHI-Wert (Apnoe-Hypopnoe-Index)
signifikant ab (5,6 ± 8,5/h; p < 0,001). 79 % erfüllten die Kriterien einer
CPAP-Therapietreue (mindestens 4 Betriebsstunden an 7 Tagen pro Woche). Es gab
keine signifikanten Einflüsse von demografischen, klinischen oder
pharmakologischen Charakteristika der Patienten auf die Therapietreue. Die
häufigsten Probleme unter CPAP-Therapie waren Trockenheit der Nasen- und
Rachenschleimhäute (43,7 %) und Druckstellen (22,4 %). Die CPAP-Therapietreue
korrelierte nicht mit den Werten der Epworth Sleepiness Scale. Die Zufriedenheit
mit der Nachsorge korrelierte signifikant mit der Therapietreue (r = 0,185; p =
0,032), während der Therapiedruck keinen signifikanten Einfluss hierauf zeigte
(r = −0,072; p = 0,383).

Schlussfolgerungen Eine strukturierte, individuell angepasste Nachsorge
ist wichtig für die Therapietreue. In Zukunft sollte im Rahmen der Nachsorge
neben der Kontrolle des Therapieerfolges mehr Aufmerksamkeit auf Aspekte der
Problemlösung, Rückkopplung, Schulung und Motivation gerichtet werden.
A Fluorenyl Activating Group Enables Addition of Simple Grignard Reagents to C=N Electrophiles
Authors: Hamilton Gregory , Mukashyaka Patience
Published: July 2018

Nucleophilic addition of organometallic reagents to ketimines and hydrazones can be a challenging transformation. Here we report the use of fluorenone-derived mixed azines which promote facile addition of Grignard reagents. The fluorenylidene activating group is easily installed and removed, thereby offering practical access to highly substituted amines and hydrazines.
C–H Monoarylation of Naphthylpyrimidines with Aryl Chlorides Catalyzed by a Water-Soluble Ruthenium Complex
Authors: Wang Zhi-Qiang , Hao Xin-Qi , Xu Chen , Li Hong-Mei , Tu Tian-Yong , Han Xin , Fu Wei-Jun , Song Mao-Ping
Published: July 2018

Selective monoarylation of naphthylpyrimidines with a variety of aryl chlorides through C–H bond activation in water was achieved by using a water-soluble [RuCl2-(η6-PhOCH2CH2OH)]2/phosphine catalytic system. The monoarylation occurred at the C-2 carbon of the naphthalene moiety, and selectively polysubstituted naphthylpyrimidines were obtained by a one-pot reaction involving a subsequent hetarylation with 2-pyridyl chlorides.
Diagnostic Value of Compression Ultrasonography and Fibrinogen-related Parameters for the Detection of Postoperative Deep Vein Thrombosis following Elective Hip Replacement: a Pilot Study
Authors: Crippa Luciano , Ravasi Flavio , D’Angelo Silvana Vigano , Varagona Roberto , Milani Emanuela , Safa Ormid , Tessari Luigi , D’Angelo Armando
Published: July 2018

To determine their ability to diagnose postoperative deep vein thrombosis (DVT) D-dimer – by three methods – fibrinogen degradation products (FgDP) and fibrinogen levels were measured in 68 consecutive patients before elective surgery for hip replacement and on postoperative day 1, 3, 6, and 10. All patients received prophylaxis and underwent compression real-time B-mode ultrasonography (C-US) on postoperative day 5 and 9, and bilateral ascending venography on day 10. Twenty-two out of 68 patients developed asymptomatic postoperative DVT, which was limited to the calf veins in 14 and involved the proximal veins in 8 patients. C-US was negative in all patients on day 5. On day 9, C-US sensitivity and specificity for proximal DVT were 63% (95% confidence interval: 26%-90%) and 98% (89%-100%) respectively. Postoperative changes in the laboratory parameters evaluated were not different in patients with or without DVT until day 10. On day 10, mean D-dimer, FgDP and fibrinogen levels were significantly higher in patients with DVT than in those without DVT (p values between 0.006 and 0.032), but only D-dimer was higher with DVT involving two or more venous segments than with thrombosis involving one venous segment only (p <0.05). Stepwise logistic regression analysis identified D-dimer and fibrinogen on day 10 as predictors of postoperative DVT. In a receiver operator curve and after weighing for the coefficients generated by logistic regression analysis, the combination of a latex photometric immunoassay and of PT-derived fibrinogen yielded - at a cut-off value of 7.0 - a sensitivity of 100% (73%-100%) and a specificity of 58% (39%-75%) for DVT, with a negative predictive value of 100% (78%-100%), a positive predictive value of 52% (32%-71%) and an overall accuracy of 71% (55%-83%). These results suggest that two simple, fast and reproducible tests may permit the identification of patients at low risk of having postoperative DVT and that a combination of sensitive laboratory assays and of the highly specific C-US may select patients requiring anticoagulant treatment. Efficacy and cost-effectiveness of this approach should be evaluated in large clinical management studies.
Low Prevalence of the Factor V Leiden Mutation Among “Severe” Hemophiliacs with a “Milder” Bleeding Diathesis
Authors: Arbini Arnaldo A , Mannucci Pier Mannuccio , Bauer Kenneth A
Published: July 2018

Patients with hemophilia A and B and factor levels less than 1 percent of normal bleed frequently with an average number of spontaneous bleeding episodes of 20–30 or more. However there are patients with equally low levels of factor VIII or factor IX who bleed once or twice per year or not at all. To examine whether the presence of a hereditary defect predisposing to hypercoagulability might play a role in amelio rating the hemorrhagic tendency in these so-called “mild severe” hemophiliacs, we determined the prevalence of prothrombotic defects in 17 patients with hemophilia A and four patients with hemophilia B selected from 295 and 76 individuals with these disorders, respectively, followed at a large Italian hemophilia center. We tested for the presence of the Factor V Leiden mutation by PCR-amplifying a fragment of the factor V gene which contains the mutation site and then digesting the product with the restriction enzyme Mnll. None of the patients with hemophilia A and only one patient with hemophilia B was heterozygous for Factor V Leiden. None of the 21 patients had hereditary deficiencies of antithrombin III, protein C, or protein S. Our results indicate that the milder bleeding diathesis that is occasionally seen among Italian hemophiliacs with factor levels that are less than 1 percent cannot be explained by the concomitant expression of a known prothrombotic defect.
Semi-Automated Detection of the Factor V Mutation by Allele Specific Amplification and Capillary Electrophoresis
Authors: Locht Louis T F van de , Kuypers Aldy W H M , Verbruggen Bert W , Linssen Peter C M , Nováková Irena R O , Mensink Ewald J B M
Published: July 2018

summary

Recently a point mutation (G1691A) in the coagulation factor V gene was shown to cause resistance for cleavage by activated protein C.The mutation is associated with an increased thrombotic risk and thus- far the most common genetic cause of thrombophilia.Current techniques to investigate the single base pair mutation at the DNA level use an assay based upon the polymerase chain reaction followed by restriction enzyme digestion or Southern blotting and allele specific probing.The method we describe here consists of a single PCR in which two specially designed allele specific primers and two consensus primers were used in one reaction to distinguish between homozygous normal,heterozygous and homozygous mutant individuals.Amplification products were analysed using Capillary Electrophoresis and on line UV monitoring.

The Allele Specific Amplification Protocol and subsequent CE analysis (ASAP-CE) is a convenient,fast,automated and highly reproducible method that can be used in a routine laboratory setting.
Effects of Ticlopidine Administered to Healthy Volunteers on Platelet Function in Whole Blood
Authors: Heptinstall S , May J A , Glenn J R , Sanderson H M , Dickinson J P , Wilcox R G
Published: July 2018

Ticlopidine is thought to be a selective inhibitor of ADP-induced platelet function. Here we have investigated the effects of ticlopidine on platelet function in whole blood induced by ADP and by other platelet agonists. Whole blood was used because it was considered that ADP derived from red cells might act synergistically with other platelet agonists to enhance platelet responses, and that ticlopidine might interfere with this process. Measurements were performed using blood from 16 healthy volunteers before ticlopidine administration, after taking ticlopidine 250 mg daily for 10 days, after taking ticlopidine 250 mg twice daily for a further 10 days, and after 14 days off treatment.

Ticlopidine proved to be a very effective inhibitor of the platelet aggregation induced by ADP; it was most effective in enhancing the reversibility of the aggregation response. The drug modestly but significantly reduced streptokinase, adrenaline, collagen, sodium arachidonate, PAF and U46619 – induced platelet aggregation. The drug significantly reduced the extent of the release reaction (14C-5HT release) induced by ADP, streptokinase, PAF, ristocetin and sodium arachidonate, and also reduced the extent of the synergistic 14C-5HT release induced by combinations of ADP and PAF, ADP and adrenaline and PAF and adrenaline.

The various inhibitory effects of ticlopidine were evident after treatment with 250 mg daily but were more pronounced after 250 mg twice daily. All values had returned to normal after 14 days off treatment. Ticlopidine had no effect on serum thromboxane B2 production nor on several parameters of coagulation and fibrinolysis.

We conclude that ticlopidine is an effective inhibitor of ADP-induced platelet aggregation and also the platelet aggregation and 14C-5HT release induced in whole blood by a number of platelet agonists and combinations of agonists. These latter effects are probably mainly via a selective effect on ADP. The inhibitory effects of the drug are dose-related.
Different Abilities of Thrombin Receptor Activating Peptide and Thrombin to Induce Platelet Calcium Rise and Full Release Reaction
Authors: Lasne Dominique , Donato José , Falet Hervé , Rendu Francine
Published: July 2018

Synthetic peptides (TRAP or Thrombin Receptor Activating Peptide) corresponding to at least the first five aminoacids of the new N-terminal tail generated after thrombin proteolysis of its receptor are effective to mimic thrombin. We have studied two different TRAPs (SFLLR, and SFLLRN) in their effectiveness to induce the different platelet responses in comparison with thrombin. Using Indo-1/AM- labelled platelets, the maximum rise in cytoplasmic ionized calcium was lower with TRAPs than with thrombin. At threshold concentrations allowing maximal aggregation (50 μM SFLLR, 5 μM SFLLRN and 1 nM thrombin) the TRAPs-induced release reaction was about the same level as with thrombin, except when external calcium was removed by addition of 1 mM EDTA. In these conditions, the dense granule release induced by TRAPs was reduced by over 60%, that of lysosome release by 75%, compared to only 15% of reduction in the presence of thrombin. Thus calcium influx was more important for TRAPs-induced release than for thrombin-induced release. At strong concentrations giving maximal aggregation and release in the absence of secondary mediators (by pretreatment with ADP scavengers plus aspirin), SFLLRN mobilized less calcium, with a fast return towards the basal level and induced smaller lysosome release than did thrombin. The results further demonstrate the essential role of external calcium in triggering sustained and full platelet responses, and emphasize the major difference between TRAP and thrombin in mobilizing [Ca2+]j. Thus, apart from the proteolysis of the seven transmembrane receptor, another thrombin binding site or thrombin receptor interaction is required to obtain full and complete responses.
Blood Coagulation and Fibrinolysis Activation during Sudden Arterial Occlusion of Lower Extremities – an Association with Ischemia and Patient Outcome
Authors: Peltonen Seija , Lassila Riitta , Rossi Perttu , Salenius Juha-Pekka , Lepäntalo Mauri
Published: July 2018

We compared hemostatic and fibrinolytic plasma markers in 41 patients having acute or subacute occlusion of lower limb arteries with 20 patients suffering stable peripheral arterial occlusive disease (PAOD). During occlusion, the amount of thrombin-antithrombin III (TAT) complex was five-fold higher compared with stable PAOD, being 16 μg/l [95% confidence interval (CI) 11-21 μg/1] vs 3 μg/l (95% CI 2-4 μg/l), p <0.003. Similarly, D-dimer was over four-fold (p = 0.0001), while tissue plasminogen activator and plasminogen activator inhibitor-1 (PAI-1) antigens were about two-fold (p = 0.02 and p <0.003, respectively) higher than in PAOD. Coagulation and fibrinolysis markers were increased most in patients with recent symptom onset, which mainly represented embolus rather than thrombosis. The marker levels assessing coagulation and fibrinolysis were related with myoglobin and CK, indicators of skeletal muscle damage. Finally, increased TAT, PAI-1 antigen, and myoglobin concentrations associated with poor outcome.
Role of FCγRIIA Gene Polymorphism in Human Platelet Activation by Monoclonal Antibodies
Authors: Bachelot Christilla , Saffroy Raphaël , Gandrille Sophie , Aiach Martine , Rendu Francine
Published: July 2018

The aim of this study was to determine if there is a correlation between the activity of a MoAb as an agonist and its ability to bind to the Fc platelet receptor, FcγRIIa. A polymorphism at amino acid 131 [arginine (Arg) or histidine (His)] of FcγRIIa was first shown to be determinant for MoAb-IgG1 binding on monocytes. To clarify the role of this polymorphism in platelet activation by MoAb-IgG1 we (i) established the FCγRIIA polymorphism at the gene level by adapting the denaturating gradient gel electrophoresis method, (ii) analyzed the binding affinity of the MoAbs to FrγRIIa on platelets from homozygous Arg, homozygous His, and heterozygous Arg/His donors, and (iii) characterized the different reactivities of platelets according to the FCγRIIA polymorphism. Among 167 Caucasian donors we found 46% heterozygous Arg/His, 36% homozygous His and 18% homozygous Arg. ALB6, an anti CD9, P256 an anti GPIIb-IIIa, and AP3 an anti-GPIIIa were chosen according to their ability (ALB6, P256) or not (AP3) to activate platelets. These 3 MoAbs-IgG1 bind to FcγRIIa with a stronger affinity for the Arg-form of FcγRIIa, a result which was confirmed with the use of diverse MoAbs directed against various antigens. The different abilities of MoAbs to bind to the two FcγRIIa forms were well correlated to the different platelet responses induced by ALB6 and P256. However, low concentrations of ALB6, which allow full activation of platelets from homozygous Arg donors, as did P256, did not induce any activation of platelets from homozygous His donors, whereas P256 is able to induce a low aggregation. The results further define the respective roles of the antigen and the Fc receptor, depending on the MoAb, and the role of the FcγRIIa polymorphism in platelet activation induced by MoAbs. In addition, the results obtained with MoAbs unable to induce platelet activation provide evidence that the binding of a MoAb on FcγRIIa does not predict its ability to activate platelets.
Smoking, Haemostatic Factors and the Severity of Aorto-lliac and Femoro-Popliteal Disease
Authors: Smith F B , Lee A J , Fowkes F G R , Rumley A , Lowe G D O
Published: July 2018

To determine relationships between haemostatic and rheological factors and severity of peripheral atherosclerosis and differences by site, an angiographic cross-sectional survey was carried out on 192 men and women with intermittent claudication or rest pain. 34 patients were classified as having aorto-iliac disease, 85 femoro-popliteal disease and 73 dual-site disease. Mean levels of haemostatic or rheological factors did not differ significantly between the three site groups. In all 192 patients, disease severity in the femoro-popliteal segments was correlated with plasma nephelometric fibrinogen (r = 0.20, p ≤0.01), von Willebrand factor (r = 0.14, p ≤0.05) and fibrin D-dimer (r = 0.22, p ≤0.001). On multiple regression analyses, fibrinogen was independently associated with disease severity in the femoro-popliteal segments (p ≤0.05), but not in the aorto-iliac segments. Adjustment for packyears or serum thiocyanate had little effect on the association of fibrinogen with severity of disease. An inverse relationship between plasminogen activator inhibitor and disease severity in the femoro-popliteal segments was found only in men (r = -0.24, p ≤0.01). We conclude that elevated fibrinogen and disturbed fibrinolytic activity may be related to the extent of disease within the femoro-popliteal arteries, more so than in the aorto-iliac arteries.
Platelet Adhesion following the Administration of Tissue-type Plasminogen Activator and Its Reversal by Vitamin E in Rats
Authors: Jen Chauying J , Dong Huei-Ping , Chen Hsiun-ing , Wing Lih-Yuh C , Tang Ming-Jer , Chang Wen-Chang , Lin Ming T , Shi Guey-Yueh
Published: July 2018

Thrombolytic therapy is known to induce platelet-related side effects. We used a parallel-plate flow chamber, which was connected to the femoral artery of the rat, to measure platelet adhesion ex vivo. A collagen-coated arterioarterial shunt between two carotid arteries was used to measure shunt patency duration as an index of antithrombotic efficacy. Tissue-type plasminogen activator (t-PA), vitamin E, and the combination of these two were intravenously administered for 60 min. Measurements were performed before drug administration, and at 30, 60, 120 min after the initiation of drug infusion. Our results indicated that (1) treatments with t-PA or t-PA/vitamin E prolonged the time to shunt occlusion at 30 and 60 min; (2) t-PA enhanced platelet adhesion at 60 and 120 min; (3) vitamin E tended to reduce platelet adhesion; (4) t-PA/vitamin E reduced the t-PA-enhanced platelet adhesion; (5) at the high-density area of platelet adhesion under t-PA treatment, the adherent platelets demonstrated severe morphological changes which could be blocked by vitamin E. These data suggest that t-PA may enhance platelet adhesion in rats and that this adverse effect can be suppressed by co-administration of vitamin E.
Inhibition by Argatroban, a Specific Thrombin Inhibitor, of Platelet Activation by Fibrin Clot-associated Thrombin
Authors: Lunven Catherine , Gauffeny Christiane , Lecoffre Catherine , O’Brien Donogh P , Roome Nigel O , Berry Christopher N
Published: July 2018

Clot-associated thrombin retains amidolytic activity, and is resistant to inhibition by heparin, but not to low molecular weight thrombin inhibitors. We show that clot-associated thrombin induces platelet aggregation, is resistant to heparin:antithrombin III, less so to recombinant hirudin (rHV2Lys47) but not to argatroban, an active-site directed thrombin inhibitor. Fibrin clots prepared with human fibrinogen and thrombin were used to aggregate rabbit washed platelets assessed by single platelet counting, thromboxane B2 (TXB2) immunoassay and scanning electron microscopy. Fibrin clots decreased platelet counts, and released TXB2. Electron microscopy showed platelet aggregates on the clot surface. Argatroban concentration-dependently inhibited such aggregation with IC50s of 21 nM and 13 nM versus aggregation and TXB2 release respectively. The IC50s of Argatroban against fluid-phase thrombin producing similar aggregation were 12 nM (aggregation) and 33 nM (TXB2). rHV2Lys47 was less active against clot-induced aggregation (IC50 = 1.8 nM) than against fluid-phase thrombin (IC50 = 0.06 nM). Heparin had an IC50 of 0.02 mU/ml against aggregation induced by fluid-phase thrombin, but much greater concentrations are required to inhibit clot-induced aggregation (IC50 = 48 mU/ml). These data provide a basis for the superiority of direct-acting thrombin inhibitors over heparin in platelet rich thrombi.
Fibrinogen Binding to ICAM-1 on EA.hy 926 Endothelial Cells Is Dependent on an Intact Cytoskeleton
Authors: van de Stolpe Anja , Jacobs Nancy , Hage Willem J , Tertoolen Leon , van Kooyk Yvette , Nováková Irena RO , de Witte Theo
Published: July 2018

Fibrinogen is a ligand for Intercellular Adhesion Molecule-1 (ICAM-1), and enhances monocyte-endothelial cell interaction by coupling Mac-1 on monocytes to ICAM-1 on endothelial cells. We investigated the role of the cytoskeleton in fibrinogen binding to the human endothelial cell line EA.hy 926 using immunofluorescence techniques. In this cell line TNFα induced the simultaneous appearance of stress fibers and of ICAM-1, which was clustered predominantly on endothelial cell projections. Incubation of TNFα-stimulated endothelial cells with fibrinogen resulted in binding of fibrinogen to ICAM-1 on these cell projections. Disruption of the cytoskeleton by cytocholasin B abolished fibrinogen binding. Activation of protein kinase C with 12-O-tetradecanoyl phorbol- 13-acetate resulted in simultaneous loss of both stress fibers and fibrinogen binding. These results suggest that a connection between ICAM-1 and the cytoskeleton results in clustering of ICAM-1 on cell projections, which is required for fibrinogen binding.
Inhibition of Protein S by Autoantibodies in Patients with Acquired Protein S Deficiency
Authors: Sorice M , Arcieri P , Griggi T , Circella A , Misasi R , Lenti L , Di Nucci G D , Mariani G
Published: July 2018

This study was undertaken to analyze antibodies to protein S (PS) in patients with an acquired PS deficiency. Plasma from symptomatic patients with acquired (n = 14) or congenital (n = 10) PS deficiency and 10 healthy donors was screened for PS antibodies by immunoblotting and for anti-phospholipid antibodies. PS antibodies (IgG) were detected in five of the patients with acquired PS deficiency. These antibodies belonged to the G1 and G4 immunoglobulin subclasses. IgG fractions from the same 5 patients were shown to inhibit PS activity. The inhibition of PS activity by the 5 IgG fractions was shown to be time-and dose-dependent and was abolished following incubation with purified PS, while no effect was found after absorption with cardiolipin micelles. In addition, anticardiolipin monoclonal or human purified antibodies, failed to exert significant PS inhibition. These findings demonstrate that anti-PS antibodies are able to inhibit PS activity and that this is independent of anti-phospholipid antibodies. Given the clinical features of the patients, these antibodies should be regarded as an expression of the broad autoimmune syndrome involving the phospholipid-binding plasma proteins.
Increased Expression of Plasminogen Activator Inhibitor-1 in R.rickettssi-infected Endothelial Cells
Authors: Shi Rui-Jin , Simpson-Haidaris Patricia J , Marder Victor J , Silverman David J , Sporn Lee Ann
Published: July 2018

Changes in PAI-1 expression in human umbilical vein endothelial cells (HUVEC) were studied following in vitro infection with Rickettsia rickettsii. A 1.8-fold increase in secreted PAI-1 activity occurred in infected versus control cultures (p = 0.03) at 24 h but not at earlier timepoints. A similar increase (1.4-fold) in secreted PAI-1 antigen (p <0.005) was measured by ELISA. To determine whether this increase was due to increased synthesis of PAI-1, HUVEC were metabolically labeled with 35S-methionine concurrent with R. rickettsii infection. Such infection resulted in a 1.9-fold increase in labeled PAI-1 in the medium at 24 h (p = 0.036). Increase in steady-state levels of PAI-1 mRNA were detected as early as 18 h by Northern blot analysis, peaking (5.5-fold) at approximately 24 h. These results indicate that PAI-1 production is increased in RR-infected endothelial cells, an effect that may contribute to the vascular occlusions noted in Rocky Mountain spotted fever.
Influence of Maximal Ergometric Exercise on Endothelin Concentrations in Relation to Molecular Markers of the Hemostatic System
Authors: Röcker Lothar , Möckel Martin , Westpfahl-W Klaus-Peter , Gunga Hanns-Christian
Published: July 2018

The effects of moderate 30 min cycle ergometer exercise (aerobic metabolism; 0.85-3.71 mmol · 1−1 lactate) followed by short-term exercise at maximal capacity (anaerobic metabolism; 5.09 to 17.75 mmol · 1−1 lactate) on endothelin (ET) and hemostatic variables (tissue plasminogen activator [t-PA] antigen, prothrombin fragments [F1,2], thrombin-antithrombin III complex [TAT], prothrombin time and partial thromboplastin time) were investigated in 15 male healthy subjects of varying fitness levels. Endothelin was measured twice, before and immediately after maximal cycle exercise. The results show an increase in endothelin concentration [10.0 pg · m1−1 (baseline) + 6.1 pg · m1−1 (increase post exercise)]. ET did not increase under control conditions. Moderate 30 min exercise caused an increase in t-PA antigen concentration (3.66 + 3.15 ng · m1−1) and short-term maximal exercise produced a markedly higher elevation in this variable (+10.6 ng · m1−1). F1,2 increased (810 + 40 pmol · 1−1) under moderate and by 150 pmol · 1−1 under anaerobic exercise. TAT increased only at maximal exercise levels (1.01 + 0.32 ng · 1−1). No changes were found in any of these variables under control conditions. No correlation of endothelin and the hemostatic variables was found.

It is concluded that endothelin and hemostatic markers increase independently during moderate and maximal exercise.
Factor V (Arg506⟶ Gln) Mutation in Young Survivors of Myocardial Infarction
Authors: Ardissino Diego , Peyvandi Flora , Merlini Piera Angelica , Colombi Elisabetta , Mannucci Pier Mannuccio
Published: July 2018

Many young patients with venous thromboembolic disease are partially resistant to the anticoagulant action of activated protein C as a result of factor V (Arg506 ⟶ Gln) mutation. The frequency of this mutation in young patients with arterial thrombotic diseases, such as myocardial infarction, is less well established. We studied 100 young patients with myocardial infarction and 100 age- and sex-matched controls. One patient (1%; 95% CL 0.05-6.2) and two controls (2%; 95% CL 0.3-7.7) were heterozygotes for the mutation; there was no homozygote in either group. Hence, premature myocardial infarction is not associated with heterozygosity for factor V (Arg506 ⟶ Gln) mutation.
The Therapeutic Range for Heparin Therapy: Relationship between Six Activated Partial Thromboplastin Time Reagents and Two Heparin Assays
Authors: Kitchen S , Preston F E
Published: July 2018

The activated partial thromboplastin time (APTT) is the most commonly used test for laboratory monitoring of unfractionated heparin therapy. Since there are differences between APTT reagents in respect of responsiveness to heparin the widely used therapeutic range of 1.5-2.5 (APTT ratios) may not be appropriate for all reagents.

The aim of this study was to assess the relationship between 6 different APTT reagents using a manual technique, 2 of these reagents used in combination with a coagulometer, a heparin assay by protamine titration and a chromogenic anti-Xa assay. Samples from 42 patients treated with unfractionated heparin for thromboembolic disease were studied, 12 of whom were receiving warfarin therapy with International Normalised Ratios (INR) of >1.3.

For normal subjects, APTT results were highly dependent on the method used and statistically significant differences were noted. The ratio of patient to mean normal APTT was calculated for each APTT method. When 30 samples from heparinised patients (with INRs of <1.3) were analysed manually, the APTT ranges equivalent to 0.2-0.4 u/ml heparin by protamine titration (by regression analysis) were 1.6-1.9 for Boehringer reagent (the least responsive) up to 2.2-2.9 for Instrumentation Laboratory reagent (the most responsive). The concentration of heparin associated on average with APTT ratios of 1.5-2.5 varied approximately twofold to threefold between reagents.
Hereditary Macrothrombocytopenia and Pregnancy
Authors: Altès Albert , Pujol-Moix Nuria , Muñiz-Diaz Eduardo , Madoz Pedro , Parra Juan , Fontcuberta Jordi
Published: July 2018

Introduction. Hereditary macrothrombocytopenias (HM) are a group of infrequent disorders characterized by hereditary giant platelets. Little has been published about the course of these diseases during pregnancy and delivery. Subjects and methods. Forty consecutive thrombocytopenic pregnant women were studied. Platelet count, mean platelet volume and blood smear examination were performed. Platelet antibodies were studied by immunofluorescence. Familial study, bleeding time, ultrastructural platelet examination, a von Willebrand disease screening and aggregation tests were carried out when HM was suspected. Results. Four cases of HM were diagnosed. Giant platelets were observed in all cases, with the typical ultrastructural pattern. Dohle-like cytoplasmic inclusions in granulocytes were observed in one case. Platelet antibodies were detected in only one case. No prophylactic measures to prevent haemorrhage were adopted, and all patients underwent vaginal deliveries. Haemorrhagic events were absent in both mothers and children. Conclusions. The prevalence of HM in pregnant trombocytopenic women is higher than assumed. Prophylactic treatment should be avoided in the absence of a history of haemorrhagic complications and obstetrical risk factors.
The Antiaggregating and Antithrombotic Activity of Ticlopidine Is Potentiated by Aspirin in the Rat
Authors: Herbert J M , Bernat A , Samama M , Maffrand J P
Published: July 2018

Since ticlopidine specifically inhibits ADP-induced platelet aggregation without affecting prostaglandin metabolism, it seemed interesting to evaluate the effect of aspirin with regard to the antithrombotic efficacy of ticlopidine. Ticlopidine was administered orally to rats alone or in combination with aspirin and the efficacy of the association was determined in several experimental models. A synergistic effect of the ticlopidine/aspirin association was demonstrated with regard to ADP- and collagen-induced platelet aggregation measured ex vivo but also in several experimental thrombosis models including silk thread-induced thrombosis in an arteriovenous shunt, wire coil-induced thrombosis and 111In-labelled platelet deposition on the subendothelium following air drying injury of the rat carotid artery. Similar results were obtained with regard to myointimal proliferation following air-induced injury of the rat carotid artery which occurred as a consequence of vascular injury. The ticlopidine/aspirin combination showed only additive-type effects on bleeding time prolongation induced by tail transection in the rat.
Genetic Diagnosis of Dysplasminogenemia: Detection of an Ala601 -Thr Mutation in 118 out of 125 Families and Identification of a New Asp676-Asn Mutation
Authors: Tsutsumi Seiji , Saito Tetsuo , Sakata Toshiyuki , Miyata Toshiyuki , Ichinose Akitada
Published: July 2018

Dysplasminogenemia (plasminogen abnormality) is frequently found in association with thrombosis. Two types of mutation, Ala601-Thr and Val355-Phe, have already been identified; the precise genetic defects of most of these patients, however, remain unknown. In this study, we examined the genetic DNAs of two unrelated cases by single-strand conformational polymorphism and nucleotide sequencing analysis. A new mutation, designated as Asp676-Asn, has been identified in these cases. This mutation leads to the loss of a negatively-charged residue and the creation of a potential carbohydrate attachment site, which may impair the enzymatic properties of plasminogen. As many as 158 individuals with dysplasminogenemia were analyzed by a combination of in vitro amplification and restriction digestion. Among 125 unrelated families, the Ala601-Thr mutation accounted for about 94% of cases. The Val355-Phe mutation was found in four unrelated families, indicating that it is a recurring mutation and is not very rare.
Association of Factor VII:C Levels with Environmental and Genetic Factors in Patients with Ischaemic Heart Disease and Coronary Atheroma Characterised by Angiography
Authors: Heywood Daniella M , Ossei-Gerning Nicholas , Grant Peter J
Published: July 2018

Elevated Factor VII:C (FVII:C) levels are an independent risk factor for acute myocardial infarction. To examine the association between FVII:C levels, genetic and environmental factors in patients with a history suggestive of ischaemic heart disease, 270 patients were studied. FVII:C levels were significantly associated with the Msp I and promoter insertion polymorphisms. FVII:C correlated with environmental factors, and these correlations remained when analysed by genotype. In a multiple regression model, genotype, body mass index, cholesterol, triglycerides and gender remained as independent and significant predictors of FVII:C levels. There was no significant difference in FVII:C concentrations with severity of atheroma, or in patients with a history of myocardial infarction. These findings provide further evidence linking FVII:C with Msp I and promoter insertion genotypes and with environmental factors in established IHD, but suggest there is not a genotype-environment interaction or a relationship between FVII:C levels and severity of ischaemic heart disease.
The Largest Isoform of Platelet Membrane Glycoprotein Iba Is Commonly Distributed in Eastern Asian Populations
Authors: Ishida Fumihiro , Furihata Kenichi , Ishida Kimitaka , Kodaira Hiroshi , Sup Han Kyou , Da-Zhuang Liu , Kitano Kiyoshi , Kiyosawa Kendo
Published: July 2018

Platelet membrane glycoprotein Iba has at least two polymorphisms which affect phenotype. One is the dimorphism at codon 145, and the other is a molecular weight polymorphism due to variable numbers of tandem repeats (TR) in the macroglycopeptide region. These two polymorphisms are in linkage disequilibrium. The frequencies of these polymorphisms differ considerably depending on race, and the largest variant with four TR is almost exclusively present in the Japanese population. We examined the genotypes of HPA-2 and TR polymorphism in three different races from Eastern Asia; the Japanese (n = 103), Korean (n = 101) and Chinese population (n = 177). The gene frequency of HPA-2 differed significantly among these three populations. Among HPA-2b-positive individuals, the A isoform with four TR and B with three TR were present in all three populations and A dominated over B. Individuals homozygous for the A isoform were found in both Japanese and Korean populations. These findings indicate that the largest haplotype is common in the Eastern Asian region.
Hemoglobin Enhances the Binding of Bacterial Endotoxin to Human Endothelial Cells
Authors: Roth Robert I
Published: July 2018

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

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

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