bluuebunny/crossref_metadata_2025 huggingface dataset:
Pluvial conditions in Wroclaw, Poland
Authors: Wartalska Katarzyna , Wdowikowski Marcin , Wilk Paweł , Oktawiec Michał , Kaźmierczak Bartosz
Published: July 2018

The paper presents rainfall conditions for the city of Wroclaw (Poland) in the multi-annual period 1960–2017. A decreasing tendency of annual precipitation totals on the level of –12.5 mm/decade and decreasing trend of the monthly total in November of –2.9 mm/decade has been shown. In remaining months, no statistically significant change trends were observed. The maximum daily rainfall amounts were recorded in summer months: 56.4 mm in June, 74.4 mm in July and 67.5 mm in August. The analysis of variability in the number of precipitation with daily amounts exceeding 10 mm showed statistically significant decreasing trends – a decrease in the number of days in the amount of 0.69 per decade (linear regression). In the case of rainfall exceeding 20 mm and 30 mm no statistically significant trends were noted – the number of days with such heavy precipitation is practically constant and amounts to an average of 3.84 and 1.44 precipitation per year.
Analysis of thermal comfort in education building in surveys
Authors: Witkowska Agata , Gładyszewska-Fiedoruk Katarzyna
Published: July 2018

Main parameters of indoor air quality could influence people health and ability to work and ability to learning. The research was conducted in University of Technology building located in Białystok, north-eastern Poland. Research - surveys was devoted to issues related to the thermal comfort in a classroom of university. Interviewees declared perceptible temperature and described their feelings connected to the temperature sensation. Other indoor parameters were also analysed such as: temperature, humidity and indoor air quality and noise level. Peoples – students filled the surveys about thermal comfort and indoor parameters. The research included indoor thermal comfort.
Architecture, that wins peaks – triumph or confusion
Authors: Wojtas Harań Anna
Published: July 2018

The natural landscape provokes artists to revive it with architecture. Architects overcome technical limitations, physiographic, customary more or less picturesquely incorporating their works into the richness of natural forms. Many benefits come from this recklessness for the region. The hit trend is also appreciated for the triumph of technical thought. It puts into confusion at once because of the gradual takeover of the natural environment. The aim of the work is to search for solutions that would help preserve the beauty of the mountain environment and at the same time make the widest group of recipients available. Analyzing the above issues, the comparative method was used, presenting achievements in the field of high-altitude objects design in extreme physiographic conditions, implemented in the Alps region. The region has a developed ski and tourist infrastructure. It is an example of maintaining moderation and specific character, despite growing new needs and expectations from tourists and sportsmen. However, it is not free from the over-investment trap.
Numerical modeling of the hydraulic impact of riparian vegetation
Authors: Wolski Krzysztof , Tymiński Tomasz , Chrobak Grzegorz
Published: July 2018

This paper presents results of numerical modelling of riverbed segment with riparian vegetation performed with use of CCHE2 software. Vegetation zones are places where dynamic of water flow increases. Therefore, there is a need of careful examination of hydraulic impact structure of such zones. Accurate research is necessary and should be performed with use of physical or numerical models, two or three dimensional. Paper presents distribution of velocity and area of water surface for two variants of vegetation deposition acquired in CCHE2D software and modelled for riverbed with distinctive riparian vegetation. Results point to significant (30–40%) increase of maximal velocities in riverbed with riparian vegetation, while directly near the vegetation there were zones with very low velocities. Local damming occurs before vegetal zone. Maximal shear stress in zones with increased velocity is significantly augmented compared to conditions with no vegetation, which can cause more intensive erosion in those zones
Optimization Algorithm for DOA Estimation of a Shallow Sea Target Based on Active Time Reversal
Authors: Jing Haixia , Wang Haiyan , Liu Zhengguo , Shen Xiaohong , Zhang Zhichen
Published: July 2018

Time reversal technique is applied to the DOA estimation of a shallow sea target, and a method based on active time reversal (ATR) is proposed to achieve correct estimation under multipath and low signal-to-noise (SNR) conditions. Combining the classical ray theory with array signal processing theory, the conventional multipath DOA estimation model based on uniform line array and the ATR-based DOA estimation model are set up respectively. The Capon algorithm is employed to simulate the models and compare it with conventional one. The simulation results show that the ATR-based estimation model can better estimate the azimuth angle of the target than the conventional counterpart, provide higher resolution and better suppress side lobes with the same signal-to-noise ratio (SNR), especially the low SNR.
Sliding Mode Variable Structure Vector Control of Permanent Magnet Synchronous Machine Servo System for Side Scan Sonar
Authors: Wu Yanchen , Wang Yingmin
Published: July 2018

To control the distance between the side scan sonar and the seabed, a permanent magnet synchronous machine(PMSM) servo system is designed, and the overall structure of the system and the design scheme of each part are presented. The maximum torque per ampere (MTPA) vector control method is adopted to enhance the power factor and dynamic performances of the system, and based on MTPA vector control method, according to the harmful effects of the dynamic load in the servo control of sonar, the sliding mode variable structure (SMVS) vector control method is proposed, and the robustness of the servo system is effectively improved. The mechanism of the MTPA and SMVS vector control method is demonstrated in detail, and their effectiveness is verified.
Structure-Preserving Analysis of Skeleton Structure of Solar Sail in the Deploying Process
Authors: Yin Tingting , Deng Zichen , Hu Weipeng , Wang Xindong
Published: July 2018

For the simplified dynamic model of the skeleton structure of solar sail in the solar power satellite via arbitrarily large phased array system (SPS-ALPHA) in the deploying process, the symplectic method is employed to simulate the dynamic behaviors of the skeleton structure of solar sail and the characteristic of vibration, the constraints default as well as the energy-preserving of the system are all discussed in this paper.Firstly, the simplified dynamic model of the skeleton structure is established based on the variational principle, which is rewritten in the form of the associated canonical equation in Hamilton framework from the Lagrange equation that describes the deploying process of the skeleton structure of solar sail. And then, the equation is numerically simulated by the symplectic Runge-Kutta method and the classical Runge-Kutta method respectively. Comparing with the classical Runge-Kutta method, the symplectic Runge-Kutta method employed in this paper can preserve the displacement constraint and the system energy well with excellent numerical stability.
Low-Energy-Orientated Resource Scheduling in Cloud Computing by Particle Swarm Optimization
Authors: Jia Jia , Mu Dejun
Published: July 2018

In order to reduce the energy cost in cloud computing, this paper represents a novel energy-orientated resource scheduling method based on particle swarm optimization. The energy cost model in cloud computing environment is studied first. The optimization of energy cost is then considered as a multiobjective optimization problem, which generates the Pareto optimization set. To solve this multiobjective optimization problem, the particle swarm optimization is involved. The states of one particle consist of both the allocation plan for servers and the frequency plans on servers. Each particle in this algorithm obtains its Pareto local optimization. After the assembly of local optimizations, the algorithm generates the Pareto global optimization for one server plan. The final solution to our problem is the optimal one among all server plans. Experimental results show the good performance of the proposed method. Comparing with the widely-used Round robin scheduling method, the proposed method requires only 45.5% dynamic energy cost.
Transoral Spine Surgery – an Update
Authors: Castein Jens , Hoffmann Christoph-Heinrich , Kandziora Frank
Published: July 2018

Even though in recent years the number of transoral spinal interventions has decreased in Europe and North America – mainly because of the progress in the drug therapy of rheumatism, there are still pathologies that can only be addressed by a transoral approach. The classical transoral approach can be expanded in collaboration with oral-maxillofacial surgery and ear, nose and throat surgery, but this is rarely necessary. The transoral approach is now mainly used for resection of pathological tissue. Additional stabilisation is often necessary and is performed in Europe and North America via a posterior approach, due to the lack of availability of anterior plate systems. Anterior plate systems are still used in India and China. In these countries, the numbers of transoral operations are generally still increasing. Today the indications for transoral spinal surgery consist mainly of infections and tumours, and more rarely of trauma and congenital malformations of the craniocervical junction. The numbers of surgical interventions for these indications has remained constant in recent years. The most recent advancement is the use of endoscopes and transnasal access. With these techniques, additional alternatives and supplements are available for further reducing the morbidity of transoral surgery. Despite the low number of cases, surgical therapy of the corresponding pathologies can be offered to patients with a calculable risk.
Der Landarzt-Abgrenzungsalgorithmus (La-Abal)
Authors: Marschner Christian , Wasem Jürgen , Heymann Romy
Published: July 2018

Vor dem Hintergrund der anhaltenden Diskussionen um die Sicherstellung der medizinischen Versorgung – insbesondere in ländlichen, strukturschwachen Regionen
Deutschlands, ist der Begriff „Landarzt“ ein häufig verwendeter Terminus. Bis dato mangelte es jedoch an einer konkreten Definition des Landarztbegriffes.
Dieses Defizit soll durch den Landarzt-Abgrenzungsalgorithmus (La-Abal) behoben werden. Anhand einer einheitlichen Abgrenzungssystematik kann nun die
Differenzierung zwischen Land- und städtisch/urban tätigen Ärzten realisiert werden. Der vorliegende Artikel gibt Auskunft darüber, ob der La-Abal generell auf
Gesamtdeutschland anwendbar ist, in welchen Regionen sich Landärzte befinden und inwieweit die als Landarztbereiche identifizierten Regionen mit hausärztlich
unterversorgten Regionen übereinstimmen. Die Methodik des La-Abals basiert im Kern auf den drei Parametern: „Grundzentrum“, „Ländliche Besiedelung“ und
„Räumliche Lage“. Einheitsgemeinden und Gemeindeverbände dienen in diesem Kontext als Analyseebene. Eindeutige, durch den La-Abal vorgegebene Bedingungen
ermöglichen es, Einheitsgemeinden/Gemeindeverbände als Landarztbereiche zu definieren und somit zu identifizieren. Als Ergebnis zeigt sich, dass der La-Abal auf
Gesamtdeutschland anwendbar ist. Des Weiteren existieren Landarztbereiche, einige davon korrespondieren mit denen als hausärztlich unterversorgt geltenden
Regionen. Der La-Abal ist ein ergebnisorientiertes, praktikables und standardisiertes Modell, das es ermöglicht, ein einheitliches Landarztverständnis zu
etablieren. Dies ist notwendig, um Antworten auf gesellschaftliche Veränderungen entwickeln und den damit einhergehenden Forderungen nach Sicherstellung der
gegenwärtigen und zukünftigen Gesundheitsversorgung gezielt planen und steuern zu können.
Signaling through G Proteins and G Protein-coupled Receptors during Platelet Activation
Authors: Brass Lawrence F , Hoxie James A , Manning David R
Published: July 2018

Recent studies have helped to define the early events of signal transduction in platelets. The best-described of these events are those in which heterotrimeric guanine nucleotide binding regulatory proteins (G proteins) mediate the interaction between cell surface receptors for agonists and intracellular second messenger generating enzymes. To date nine different G proteins have been identified in platelets. The:r targets include phospholipases C and A2, and adenylyl cyclase. Efforts to clone the receptors that can couple to these G proteins have been successful for epinephrine, thrombin, TxA2 and platelet activating factor. Each of these is comprised of a single polypeptide with seven transmembrane domains and an extracellular N-terminus. In the case of the thrombin receptor, activation occurs by a novel mechanism in which thrombin cleaves its receptor, creating a new N-terminus that can serve as a tethered ligand. Shortly after activation, thrombin receptors become resistant to re-activation by thrombin. This desensitization, which appears to involve receptor phosphorylation and internalization, provides a potent mechanism for limiting the duration of thrombin-initiated events in platelets and other thrombin-responsive vascular cells.
Low-Dose Heparin and Deep-Vein Thrombosis after Total Hip Replacement
Authors: Mannucci P. M , Citterio Luisa E. , Panajotopoulos N
Published: July 2018

The effect of subcutaneous low-dose heparin on postoperative deep-vein thrombosis (D. V. T.) (diagnosed by the 125I-labelled fibrinogen test) has been investigated in a trial of 143 patients undergoing the operation of total hip replacement. Two randomized studies were carried out: in one the scanning for D.V.T. was carried out daily for 7 days post operatively and in the other for 15 days. In both, the incidence of D.V.T. was significantly lower in the heparin-treated patients (P<0.005). Bilateral D.V.T. was also prevented (P<0.05), through the extension of D.V.T. to the distal veins of the thigh was not significantly reduced. Heparin treatment was, however, followed by a higher incidence of severe postoperative bleeding (P< 0.02) and wound haematoma formation (P< 0.005), and the postoperative haemoglobin was significantly lower than in the control group (P<0.005). A higher number of transfused blood units was also needed by the heparin treated patients (P<0.001).
Effects of Matrix Contact during Gel Filtration of Human Platelets in Plasma
Authors: Lindon Jack N. , Rodvien Robert , Waugh David F.
Published: July 2018

When gel filtration is used to transfer platelets from plasma into an established environment, alterations in platelet characteristics may result from the change in environment or from the effects of platelet contact with the gel matrix. To approach the problem of evaluating the relative contributions from these sources, a Sepharose 2B matrix was employed and platelets transferred from citrate anticoagulated PRP into autologous PPP to yield plasma-GFP. Platelet recoveries averaged 93 %. PRP: plasma-GFP pairs were found to be indistinguishable with respect to: morphology; ADP, thrombin or collagen-induced aggregation response; uptake of 5-hydroxytryptamine (5-HT) or adenosine; and thrombin or collagen-induced release of accumulated 5-HT or adenosine. Pairs are distinguishable by prostaglandin E2 synthesis assayed immediately after filtration.
Platelet Dysfunction in Migraine: Effect of Self-Medication with Aspirin
Authors: Deshmukh Sunanda V. , Meyer John Stirling , Mouche Richard J.
Published: July 2018

Circulating microembolic index (CMI) was determined by drawing one blood sample into EDTA-formalin and the other into DTA alone in patients with migraine and compared with matched normal controls. Platelet aggregates, if any, are fixed in EDTA-formalin but dis- aggregated by EDTA. Ratios of these two counts approximate “unity” in normals and are proportionately less than unity, depending on the number of platelet aggregates. 26 untreated migraineurs and 19 migraineurs with history of self-medication with aspirin taken within 72 hours of the test, were studied in headache-free intervals. Results were compared with those from 20 healthy, age and sex matched volunteers, without migraine, who were medication- free for at least one week. Mean CMI in untreated migraineurs (0.77±0.03 SEM) was significantly lower than the mean in normal controls (0.94±0.02, p. <0.002). Migraineurs with selfadministration of aspirin had mean CMI of 0.88±0.02, differing significantly from untreated migraineurs (p <0.01) but not from normal controls (0.1<p<0.2). Results suggest excessive platelet aggregation in migraineurs which tends to be corrected by treatment with platelet inhibitors such as aspirin.
Release, Aggregation and Lysis of Human Platelets by Antilymphocyte Globulin and Antiplatelet Serum
Authors: Lekas Nicholas , Rosenberg J. C
Published: July 2018

Human platelets labeled with 51Cr were used to determine the contribution made by platelet lysis to the platelet release reaction and platelet aggregation induced by rabbit antihuman platelet serum (APS) and equine antihuman thymocyte globulin (ATG). Platelets were tested in both plasma (PRP) and non-plasma containing media. Antibodies directed against platelets, either as APS or ATG, induced significant amounts of platelet release and aggregation, as well as some degree of lysis, in the absence of complement. The presence of complement increased platelet lysis and aggregation, but not the release reaction. Non-immune horse gamma globulin produced different responses depending upon whether platelets were investigated in PRP or non-plasma containing media. Aggregation was seen in the latter but not the former. These differences can be explained by the presence of plasma components which prevent non-specific immune complexes from causing platelet aggregation. Since platelets in vivo are always in a plasma medium, one must be wary of utilizing data from platelet studies in synthetic plasma-free media as the basis of explaining clinical events. These observations demonstrate at least two, and possibly three, different mechanisms whereby ATG could activate platelets causing thrombotic complications and thrombocytopenia, i.e., via 1) specific and, 2) non-specific non-lytic pathways and 3) a lytic pathway.
An immunological Method for Detection of the Carrier of Hemophilia B
Authors: Matsuoka Matsuzo , Ito Masakazu , Takahashi Kaoru , Sakuragawa Nobuo
Published: July 2018

This paper presents the results of an immunological study of hemophilia B and its carriers which used two kinds of antibodies, a heterologous antibody of high specificity and a homologous antibody developed in a patient with severe hemophilia B.

1. The factor IX related antigen for hemophilia B could be determined by a neutralization test and not by a precipitation reaction.

2. The activity of factor IX in a definite carrier of hemophilia B was significantly lower than that of factor VIII in a definite carrier of hemophilia A.

3. In hemophilia B, there were no differences between the factor IX antigen determined by either the heterologous rabbit antibodies or the homologous antibodies. And there was no discrepancy between the factor IX antigen and the factor IX activity. Therefore, we cannot use this discrepancy for the detection of a carrier of hemophilia B.

4. However, there was a discrepancy between the factor IX antigen determined by the neutralization test and the factor IX procoagulant activity in the patients of both hemophilia BM and hemophilia B+. The identical results were obtained in the cases of carriers of both hemophilia BM and hemophilia B+. These facts are very useful for the detection of carriers of hemophilia BM and hemophilia B+.
Effects of Ions on ADP-Induced Aggregation of Bovine or Human Platelets
Authors: Waugh David F. , Lindon Jack N.
Published: July 2018

Effects of divalent cations on ADP-induced aggregation response were examined. Bovine platelets were transferred by Sepharose 2B gel filtration from citrate-PRP into citrate free buffer (buffer-GFP). Response increases, reaches a maximum and decreases with increasing calcium and/or magnesium concentration. For either calcium or magnesium alone, increasing response is proportional to a rate coefficient and, through an apparent ion-platelet association constant, to the fraction of platelet critical sites bound to cation. With both ions present, bound magnesium appears to inhibit bound calcium in excess of that accounted for by competition and a lower rate coefficient for bound magnesium. With citrate present in buffer-GFP, apparent association constants increase, excess magnesium inhibition is present, but systems are path dependent. Initial conditions appear to establish a response which is thereafter immutable to environmental magnesium alteration. Citrate-PRP resembles buffer-GFP: response is sensitive to the selective removal of calcium and excess magnesium inhibition is present. With heparin-PRP, response is immutable to the selective removal of ~90% of initial calcium. The dependency of response inhibition observed at high divalent cation concentrations indicates that aggregation is not due to interplatelet cross linking by ions. Ion effects are similar for bovine and human platelets.
Clottability and Cross-Linking Reactivity of Fibrin(ogen) Following Differential Release of Fibrinopeptides A and B
Authors: Furlan M , Seelich T , Beck E. A
Published: July 2018

Human fibrinogen was treated at pH 6.0, 7.3 and 9.0 with thrombin, batroxobin (thrombinlike fraction of Bothrops atrox venom) or an extract of the venom from Ancistrodon contortrix contortrix. These three enzymes released the NH2-terminal fibrinopeptides A and B at different rates. Thrombin-free, preactivated factor XIII (factor XIIIa) was added to incubation mixtures to stabilize resulting fibrin(ogen) aggregates. Cross-linking of γ-chains and the size of covalently linked fibrin-fibrinogen oligomers were studied in an early stage of fibrinopeptide cleavage using polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate.

Batroxobin (pH 7.3) and thrombin (pH. 6.0) preferentially released fibrinopeptide A, and resulting fibrin aggregates became rapidly insoluble. However, when fibrinopeptide B was removed with the contortrix enzyme, soluble cross-linked oligomers appeared initially. The opaque fibrin clots, produced by thrombin (pH 6.0) or contortrix procoagulant fraction (pH 7.3), were found to be devoid of α-polymers even after prolonged incubation with factor XIIIa. Our data suggest that the solubility and opacity of fibrin networks are not primarily related to the type of the cross-link (γ-γ versus α-α interactions).
In Vivo Anticoagulant and Antiplatelet Effect of D-Phe-Pro-Arg-H and D-MePhe-Pro-Arg-H
Authors: Bagdy Dániel , Barabás Éva , Szabó Gabriella , Bajusz Sándor , Széll Erzsébet
Published: July 2018

D-Phe-Pro-Arg-H and D-MePhe-Pro-Arg-H synthetized in our institute were administered to mice, rats, rabbits and beagle dogs. The kinetics of the anticoagulant and antiplatelet effect was recorded by measuring various clotting parameters, platelet count and aggregation, and evaluated as proposed by Verstraete and Verwilghen. The minimum effective doses were found to be 0.25-0.5 mg kg-1h-1 by intravenous continuous infusions and 0.5-1.0 mg/kg by single injections. The dose-dependent prolongation of clotting times appeared after application within minutes and returned to baseline values as a function of dose. Blood level of the inhibitors was determined by a bioassay. Unlike heparin, no higher starting dose was required to reach the anticoagulant threshold level, i.e. 0.03-0.1 ¼g/ml whole blood. The peptides did not cause significant changes in platelet count and function or in hemodynamic parameters (blood pressure, heart rate and ECG) and in respiration. They blocked platelet aggregation induced by thrombin ex vivo specifically. No rebound effect or bleeding could be demonstrated even after subtoxic doses of the compounds. The onset of the anticoagulant and antithrombotic effect appeared within 60 min after single oral doses and lasted for 3-6 h. In close correlation with the anticoagulant effect a complete or significant inhibition of platelet aggregation induced by thrombin ex vivo could also be recorded by using 5-10 mg/kg doses.
Thrombin Activity by Intrinsic Activation of Plasma In-Vitro Accelerates with Increasing Age of the Donor
Authors: Ibbotson S H , Tate G M , Davies J A
Published: July 2018

Thrombotic diseases increase in incidence with advancing years and this might be partly due to an increased propensity for fibrin formation in older individuals. Accordingly we decided to investigate whether the time taken to generate 50% thrombin activity in vitro varied with the age of the plasma donor. Coagulation was initiated in defibrinated, diluted plasma by contact activation and thrombin activity measured using the chromogenic substrate, S2238. The rate of thrombin generation was assessed by measuring the time taken to reach 50% maximal activity (T50/s). There was a highly significant negative correlation between T50 and age, T50 declining from 93 s at 19 years to 71 s at 65 years (r = −0.637, p <0.0001). A strong negative correlation was demonstrated between T50 and FVII level (r = -0.415, p = 0.0007) and FVIII: C level (r = -0.465, p = 0.0001). Although FVII concentration correlated with age (r = 0.307, p = 0.014) no relationship was seen between age and FVIII :C. These data suggest that coagulation rates in plasma accelerate with age.
D-Dimer and Thrombin-Antithrombin III Complexes in Patients with Clinically Suspected Pulmonary Embolism
Authors: Demers Christine , Ginsberg Jeffrey S , Johnston Marilyn , Brill-Edwards Patrick , Panju Akbar
Published: July 2018

One hundred and fifty-six consecutive patients with clinically suspected pulmonary embolism (PE) had blood drawn to measure levels of D-dimer and thrombin-antithrombin (TAT) complexes and underwent ventilation/perfusion (V/Q) lung scanning and bilateral impedance plethysmography (IPG); pulmonary angiography was performed in 10 patients. Patients were classified as: PE-positive (positive pulmonary angiography or high probability lung scan or non-high probability lung scan and abnormal IPG) or, PE-negative (normal lung scan or normal pulmonary angiography) or PE-unlikely (non-high probability lung scan and normal serial IPG and absence of venous thromboembolism in follow-up). Thirty patients were classified as PE-positive, 64 as PE-negative and 62 patients as PE-unlikely. PE-positive patients were treated with anticoagulants, whereas PE-negative and PE-unlikely patients were not. PE-unlikely patients were followed for 3 months with repeat IPG and clinical evaluation for the occurrence of venous thromboembolism. The sensitivities, specificities, positive predictive values and negative predictive values of the D-dimer and TAT complex assays were calculated for patients classified as PE-positive and PE-negative. In addition, the prevalences of normal D-dimer and TAT complex assays were calculated for PE-unlikely patients.

Cutoffs of 300 ng/ml for D-dimer and 3.5 μg/ml for TAT complexes provided sensitivities of 96% for both assays, negative predictive values of 97% for D-dimer and 96% for TAT complexes and specificities of 52% for D-dimer and 51% for TAT complexes. The specificities of the assays were higher in patients without comorbid conditions and in outpatients. Among PE-unlikely patients, 14 had normal D-dimer levels and 5 had normal levels of TAT complexes. None of these patients developed venous thromboembolism in follow-up.

Our study indicates that: 1) PE is highly unlikely in patients who have D-dimer levels of less than 300 ng/ml and/or levels of TAT complexes below 3.5 μg/ml, and 2), because of their relatively low positive predictive values, further investigation is required if levels of D-dimer and/or TAT complexes are above these cutoffs. These results should be confirmed in future clinical management trials.
A Collaborative Study to Establish an International Standard for Alpha-Thrombin
Authors: Gaffney P J , Heath A B , Fenton II J W
Published: July 2018

Since 1975 an International Standard for Thrombin of low purity has been used. While this standard was stable and of value for calibrating thrombins of unknown potency the need for a pure a-thrombin standard arose both for accurate calibration and for precise measurement of thrombin inhibitors, notably hirudin. An international collaborative study was undertaken to establish the potency and stability of an ampouled pure a-thrombin preparation. A potency of 97.5 international units (95% confidence limits 86.5-98.5) was established for the new a-thrombin standard (89/ 588) using a clotting-assay procedure. Stability data at various elevated temperatures indicated that the standard could be transported and stored with no significant loss of potency.

Ampoules of lyophilised a-thrombin (coded 89/588) have been recommended as an International Standard for a-thrombin with an assigned potency of 100 international units per ampoule by the International Society for Thrombosis and Haemostasis (Thrombin and its Inhibitors Sub-Committee) in Barcelona, Spain in July 1990 while the Expert Committee on Biological Standardisation and Control of the World Health Organisation will consider its status at its next meeting in Geneva in 1991.
Gemfibrozil Reduces Plasma Prothrombin Fragment F1+2 Concentration, a Marker of Coagulability, in Patients with Coronary Heart Disease
Authors: Wilkes H C , Meade T W , Barzega S , Foley A J , Hughes L O , Bauer K A , Rosenberg R D , Miller G J
Published: July 2018

The effects of gemfibrozil on several indices of haemostatic activity were explored in male patients with coronary heart disease (CHD). Sixty-three of 71 patients completed a crossover study in which gemfibrozil 1,200 mg/day and matching placebo were each taken in randomised order for 2 months in a doubleblind manner, separated by a 2-month washout period. Serum cholesterol decreased by an average (95% confidence interval) of 12 (9 to 15)% and non-fasting triglyceride concentration by 43 (34 to 51)% during active treatment. Plasma prothrombin fragment Fi + 2 concentration, a marker of the in vivo rate of generation of thrombin, was 25 (12 to 37)% lower on average while on gemfibrozil than during the placebo phase. Factor VII coagulant activity (VIIC) and antigen concentration, and fibrinopeptide A concentration were not influenced by gemfibrozil in the group overall. However, the VIIC response appeared to be dependent upon the untreated cholesterol level. Hypercholesterolaemic men (cholesterol >6.5 mmol/1) experienced a significant reduction in VIIC averaging 6% of standard during active therapy. Other effects of gemfibrozil were a 5 (2 to 9)% increase in plasma fibrinogen by a gravimetric method, an 11 (8 to 13)% increase in platelet count, and a 6 (2 to 10)% reduction in white cell count. The reduced incidence of CHD following gemfibrozil therapy in hyperlipidaemic patients may arise in part through a reduction in procoagulant activity and thus the risk of an occlusive coronary thrombosis.
Insertions/Deletions in the Antithrombin Gene: 3 Mutations Associated with Non-Expression
Authors: Daly Martina , Perry David J , Harper Paul L , Daly Helena M , Roques Antoine W W , Carrell Robin W
Published: July 2018

We have investigated the molecular basis of antithrombin deficiency in 3 individuals, 2 of whom had a proven family history of thromboembolic disease. An approximate 50% reduction in functional and immunologic levels of antithrombin was detected in plasma from the propositi indicating an allelic deficiency of antithrombin. In each case direct sequencing of amplified DNA revealed a novel mutation involving single bases: two being insertions, of a T in codon 48 and an A in codon 208, and the third being the deletion of an A in codon 370. The three mutations, which were confirmed by cloning and sequencing the normal and variant alleles, all caused frameshifts leading to premature termination of protein translation. In no case could a truncated antithrombin be detected in plasma from the propositus suggesting either that it fails to be secreted, or is rapidly degraded.
Membrane Fluidity Is Related to the Extent of Glycation of Proteins, but not to Alterations in the Cholesterol to Phospholipid Molar Ratio in Isolated Platelet Membranes from Diabetic and Control Subjects
Authors: Winocour Peter D , Watala Cezary , Kinglough-Rathbone Raelene L
Published: July 2018

Platelets from diabetic subjects are hypersensitive to aggregating agents in vitro. Membrane fluidity modulates cell function and we previously reported reduced membrane fluidity associated with hypersensitivity to thrombin in intact platelets from diabetic subjects. Reduced membrane fluidity and hypersensitivity to agonists has also been reported in platelets from non-diabetic subjects whose platelets have an increased cholesterol/phos-pholipid molar ratio. Glycation of platelet membrane proteins is enhanced in diabetic subjects, and could contribute to the decreased membrane fluidity in these platelets. We examined the relation among fluidity, cholesterol/phospholipid molar ratio, and glycation of proteins in isolated platelet membranes from diabetic and control subjects. Seven poorly controlled diabetic subjects were compared with 7 age- and sex-matched control subjects. The mean steady-state fluorescence polarization value in 1,6-diphenyl-1,3,5-hexatriene-labeled isolated platelet membranes from diabetic subjects (0.184 ± 0.004) was significantly greater than from control subjects (0.171 ± 0.004, p <0.01); thus, fluidity in platelet membranes from diabetic subjects is decreased. Reduced fluidity in platelet membranes from diabetic subjects could not be attributed to changes in the cholesterol/phospholipid molar ratio. Total or very low density (VLDL), low density (LDL), or high density (HDL3) lipoprotein cholesterol concentration in plasma was not significantly different between groups, but the ratio of VLDL + LDL to HDL2 + HDL3 cholesterol was significantly greater in diabetic subjects (4.79 ± 0.73) than in control subjects (2.54 ± 0.30, p <0.02). Proteins were glycated significantly more extensively in platelet membranes from diabetic subjects (25.5 ± 0.9 nmol glucose/mg protein) than those from control subjects (21.0 ± 0.6 nmol glucose/mg protein, p <0.001). The extent of glycation of proteins in platelet membranes correlated significantly with the steady state fluorescence polarization values for platelet membranes from diabetic and control subjects (r = 0.715, p <0.01). More extensive glycation of proteins appears to be associated with reduced fluidity of platelet membranes from diabetic subjects, but not with increased cholesterol/phospholipid molar ratio.
Monoclonal Antibody-Based Enzyme-Linked Immunosorbent Assays (ELISA) for the Measurement of Vitamin K-Dependent Protein S: The Effect of Antibody Immunoreactivity on Plasma Protein S Antigen Determinations
Authors: D’Angelo Silvana Vigano , Tombesi Sandra , Marcovina Santica , Albertini Alberto , Valle Patrizia Della , D’Angelo Armando
Published: July 2018

Two monoclonal antibodies (Mabs) specifically directed to human protein S (PS) - named 5E9E9 and 3B10.25 - were produced and their properties compared to those of 2 previously characterized anti-PS-Mabs (HPS-2 and S10). 3B10.25, similar to S10, was directed to the calcium-free conformation of PS and had virtually identical affinity for free and C4b-binding protein (C4b-BP)-bound PS; 5E9E9 similar to HPS-2, had no calcium-dependency and was selectively directed to free PS. All Mabs were equally reactive to freshly purified and thrombin-cleaved PS. To evaluate the influence of C4b-BP bound PS on PS antigen determinations, ELISA systems employing the four Mabs individually as capture antibody (Ab) and peroxidase-conjugated polyclonal anti-PS IgG as detecting Ab were developed and compared to immunoelectrophoresis (EIA) and to an ELISA employing polyclonal anti-PS IgG as capture and detecting Ab, in the determination of PS in purified systems and in plasma. With all the ELISAs there was parallelism of dilution cuiyes obtained with normal plasma and purified PS; however, supplementation of plasma with purified C4b-BP resulted in loss of parallelism when employing the Mabs directed to free PS as capture Ab. Influence of high C4b-BP on PS antigen determinations was confirmed in a series of plasma samples from patients with C4b-BP levels ranging from 70% to over 200%. Compared to the values obtained with the S10- or 3B10.25 - based ELISAs - which were similar despite a 10-fold difference in sample dilution -plasma PS was underestimated by the ELISAs employing 5E9E9 or HPS-2 while it was overestimated by EIA. In addition, plasma PS and C4b-BP levels were significantly correlated only when it was measured by EIA or the ELISAs employing S10, 3B10.25 or polyclonal IgG. These results highlight the potential influence of high C4b-BP on plasma PS antigen determination. Accurate measurement of PS by ELISA requires selection of antibodies with identical affinity for all plasma PS forms.
Heparin Binding to Plasma Proteins, an Important Mechanism for Heparin Resistance
Authors: Young Edward , Prins Martin , Levine Mark N , Hirsh Jack
Published: July 2018

Heparin dosage requirements vary widely among patients with venous thromboembolism. In this study, we measured the proportion of anticoagulantly-active heparin which was reversibly bound and neutralized by plasma proteins (defined as reversible heparin neutralization) in the pre-treatment plasma (in vitro) and in the 6 h post-treatment plasma (ex vivo) of patients with venous thromboembolism treated with a fixed dose of heparin. Reversible heparin neutralization was assessed by comparing the heparin levels measured as anti-factor Xa activity before and after the addition of low affinity heparin which is essentially devoid of antifactor Xa activity, in order to displace heparin bound to plasma proteins. The results indicate that reversible heparin neutralization due to binding to plasma proteins is a major determinant of the anticoagulant response to a fixed dose of standard heparin 6 h post-treatment and of the eventual heparin dose required to achieve a therapeutic anticoagulant effect on days 3-5 of heparin treatment.
The Role of Phospholipids and the Factor VII Gla-Domain in the Interaction of Factor VII with Tissue Factor
Authors: Wildgoose Peter , Jørgensen Tony , Komiyama Yutaka , Nakagaki Tomohiro , Pedersen Anders , Kisiel Walter
Published: July 2018

Whether or not the factor VII Gla-domain is involved in the high-affinity interaction of factor VII and tissue factor via calcium-dependent interactions with surrounding phospholipids is unknown. To investigate this, we have purified the factor VII Gla-peptide (FVII-GP) from digested recombinant human factor VII a and assessed its effect on factor VII: tissue factor interactions. FVII-GP inhibited the activation of factor X by factor Vila in the presence of either soluble or cell surface tissue factor halfmaximally at 0.5 μM and 2.7 μM, respectively. However, FVII-GP failed to inhibit the specific binding of factor Vila to cell-surface tissue factor, and did not inhibit the ability of tissue factor to stimulate the amidolytic activity of factor Vila. Unrelipidated tissue factor apoprotein stimulated the amidolytic activity of factor Vila to the same extent as relipidated tissue factor apoprotein. These findings suggest that the factor VII Gla-domain does not directly interact with tissue factor, but rather is important for calcium binding and concomitant expression of other factor VII epitopes necessary for tissue factor recognition and binding. To test this hypothesis, we have prepared a monoclonal antibody against a putative factor VII epitope that participates in the interaction of factor VII with cell-surface tissue factor (peptide 195-206) and assessed its ability to bind to factor VII in the presence and absence of calcium. Binding of this monoclonal antibody (PW-4) to intact factor VII a was calcium-dependent and could be inhibited in a dose-dependent manner by peptide 195-206. The antibody reacted with Gla-domainless factor Vila, but only 37% as compared to intact factor Vila. In addition, PW4 as well as its Fab’ fragment, inhibited factor Vila binding to cell-surface tissue factor. These studies indicate that the factor VII Gla-domain does not provide structural elements that contribute to the formation of a stable factor VII/VII a-tissue factor binary complex. The factor VII Gla-domain appears to be necessary, however, in binding calcium ions and inducing a calcium-dependent conformational change in factor VII/VII a that expresses one or more neoepitopes that participates in the interaction of factor VII/VII a with the extracellular domain of tissue factor apoprotein.
Comparison of Recombinant Plasminogen Activator Inhibitor-1 and Epsilon Amino Caproic Acid in a Hemorrhagic Rabbit Model
Authors: Racanelli Adrienne L , Diemer Mark J , Dobies A Cathy , Dubin Joan R , Reilly Thomas M
Published: July 2018

A rabbit ear model of blood loss was developed to compare the effects of an active form of recombinant plasminogen activator inhibitor-1 (rPAI-1) with epsilon amino caproic acid (EACA) in antagonizing tissue-type plasminogen activator (r-tPA)-induced blood loss. The antagonism of both rebleeding, which occurs as a result of hemostatic plug degradation, and r-tPA-induced hemorrhage, where rabbits lose approximately 30% of their blood volume, was studied. rPAI-1 (1 mg/kg i. v.) or EACA (70 mg/kg i. v.) antagonized the rebleeding induced by r-tPA (10 μg kg-1 min-1) to a similar extent. In the hemorrhagic studies, rPAI-1 effectively antagonized the r-tPA-induced hemorrhage with an ED50 of 3 mg/kg i. v., while the ED50 obtained for EACA was 230 mg/kg i. v. rPAI-1 may be of value in reversing r-tPA-induced blood loss during thrombolytic therapy or in clinical situations where excessive fibrinolysis contributes to bleeding.
Platelet Interaction with Collagen Fibrils in Flowing Blood
Authors: Baumgartner Hans R. , Tschopp Thomas B. , Weiss Harvey J.
Published: July 2018

Anticoagulated whole blood from patients and control subjects was circulated through an annular perfusion chamber in which the fibrillar collagen of α chymotrypsin-digested subendothelium and intact subendothelium were exposed. The blood flow conditions corresponded to those in arteries (830 sec–1 wall shear rate). Platelet surface interaction was measured mor-phometrically.

Decreased adhesion to fibrillar collagen associated with normal spreading and normal adhesion-induced formation of platelet thrombi was found with blood of patients with von Willebrand’s disease and the Bernard Soulier Syndrome, indicating a defect in the initial attachment reaction of platelets with collagen. Platelets of patients with thrombasthenia did normally adhere to the collagen fibrils and also lost their subcellular organelles during this reaction, but they totally failed to adhere to each other. In storage pool disease platelet thrombus formation was consistently inhibited whereas adhesion and spreading was inhibited in some patients and normal in others. In contrast adhesion was always normal after ingestion of aspirin which consistently caused a marked inhibition of platelet thrombi. These findings correspond – in essence – to those previously described on intact subendothelium. However, the observed defects are more pronounced on the fibrillar collagen than on intact subendothelium.
A Comparative Ex Vivo Study of Plasminogen Activators and Proteases for Fibrinolytic Activity and Side Effects in Rabbits
Authors: Janik B. A , Papaioannou S. E
Published: July 2018

Urokinase, streptokinase, Brinase, trypsin, and SN 687, a bacterial exoprotease, have been evaluated in an ex vivo assay system. These enzymes were injected into rabbits and the fibrinolytic activity as well as other coagulation parameters were measured by in vitro techniques. Dose-response correlations have been made using the euglobulin lysis time as a measure of fibrinolytic activity and the 50% effective dose has been determined for each enzyme. Loading doses, equal to four times the 50% effective dose, were administered to monitor potential toxicity revealing that Brinase, trypsin, and SN 687 were very toxic at this concentration.

Having established the 50% effective dose for each enzyme, further testing was conducted where relevant fibrinolytic and coagulation parameters were measured for up to two days following a 50% effective dose bolus injection of each enzyme. Our results have demonstrated that urokinase and streptokinase are plasminogen activators specifically activating the rabbit fibrinolytic system while Brinase, trypsin and SN 687 increase the general proteolytic activity in vivo.

The advantages of this ex vivo assay system for evaluating relative fibrinolytic potencies and side effects for plasminogen activators and fibrinolytic proteases have been discussed.
In Vitro and in Vivo Measurement of Total Antiplasmin Activity
Authors: Matsuo Osamu , Mihara Hisashi
Published: July 2018

Total antiplasmin was measured in vitro and in vivo. In the former case, rabbit plasma was mixed with various concentrations of Urokinase (UK) and the least concentration for appearance of fibrinolytic activity was estimated. This concentration was multiplied by the plasma volume of the rabbit to give the in vitro total antiplasmin. The mean value for 14 rabbits was 4,068.6 units.

In order to estimate the total antiplasmin in vivo, UK solution was infused into rabbits. The infusion speed was multiplied by the time of the first appearance of fibrinolytic activity to give the total antiplasmin, although when the infusion speed was low, fibrinolytic activity did not appear during infusion. The mean in vivo total antiplasmin calculated for 6 cases where the infusion speed was high and fibrinolytic activity was observed, was 28,699.8 units, i.e. about 7 (range, 3-11) times the in vitro value.
Comparative Studies of Coagulative and Fibrinolytic Faculties between the Japanese Monkey and the Human
Authors: Suzuki K , Egawa H , Hashimoto S
Published: July 2018

In the present study, the coagulative and the fibrinolytic faculties of the Japanese monkey (Macaca fuscata) were investigated and compared with those of the human.

Regarding the coagulative faculty, the plasmic fibrinogen level, prothrombin times, and partial thromboplastin times of the Japanese monkey were similar to those of the human, but the antithrombin level in the monkey was higher than that in the human.

Regarding the fibrinolytic faculty, the simian plasminogen level was significantly higher than the human, but the simian, plasma clot and the euglobulin clot lysis times were extremely prolonged, which means that the Japanese monkey has a great fibrinolytic potential, but that it is difficult to activate.

In addition, the human and simian reactivities of plasminogen to streptokinase were also investigated and compared.