bluuebunny/crossref_metadata_2025 huggingface dataset:
Structure–activity relationship of novel low-generation dendrimers for gene delivery
Authors: Gao Yong-Guang , Lin Xiao , Dang Kai , Jiang Shan-Feng , Tian Ye , Liu Fen-Li , Li Di-Jie , Li Yu , Miao Zhi-Ping , Qian Ai-Rong
Published: July 2018

Structure–activity relationship (SAR) studies are very critical to design ideal gene vectors for gene delivery.
Total synthesis of (±)-swermirin
Authors: He Ping , Wang Zhang
Published: July 2018

The synthesis of swermirin features two sequential regioselective Stille couplings and a spontaneous 6π-electrocyclization.
A perylene diimide-based electron transport layer enabling efficient inverted perovskite solar cells
Authors: Jiang Kui , Wu Fei , Yu Hui , Yao Yanqing , Zhang Guangye , Zhu Linna , Yan He
Published: July 2018

High efficiencies of 16.29% and 18.78% are obtained in inverted PSCs using TPE-PDI4 as an electron transporting material and interfacial material, respectively.
Collagen skin, a water-sensitive shape memory material
Authors: Han Yanting , Hu Jinlian , Jiang Lei
Published: July 2018

The water sensitive shape memory ability of collagen skin and its mechanism in terms of morphology and structures were revealed.
Cystamine and cysteamine as inhibitors of transglutaminase activityin vivo
Authors: Jeitner Thomas M. , Pinto John T. , Cooper Arthur J.L.
Published: July 2018

Cystamine is commonly used as a transglutaminase inhibitor. This disulphide undergoes reduction in vivo to the aminothiol compound, cysteamine. Thus, the mechanism by which cystamine inhibits transglutaminase activity in vivo could be due to either cystamine or cysteamine, which depends on the local redox environment. Cystamine inactivates transglutaminases by promoting the oxidation of two vicinal cysteine residues on the enzyme to an allosteric disulphide, whereas cysteamine acts as a competitive inhibitor for transamidation reactions catalyzed by this enzyme. The latter mechanism is likely to result in the formation of a unique biomarker, N-(γ-glutamyl)cysteamine that could serve to indicate how cyst(e)amine acts to inhibit transglutaminases inside cells and the body.
Real-time quantitative PCR: a reliable molecular diagnostic and follow-up tool for ‘minimal residual disease’ assessment in chronic myeloid leukemia
Authors: Azad Niyaz A. , Shah Zafar A. , Pandith Arshad A. , Rasool Roohi , Jeelani Samoon
Published: July 2018

Molecular monitoring of BCR-ABL transcript levels by real-time quantitative PCR is increasingly being used to diagnose the disease and assess treatment response in patients with chronic myeloid leukemia (CML). This has become particularly relevant when residual levels of leukemia usually fall below the level of detection by cytogenetic analysis. Forty-two CML patients, including 18 males (42.86%) and 24 females (57.14%) aged 7–75 years, were enlisted for the study and followed-up for the response to imatinib treatment. Patients were subjected to Multiplex RT-PCR (reverse-transcriptase PCR) and were all found to harbor either e13a2 or the e14a2, which could be analyzed by a single Taqman probe based quantitation kit (Geno-Sen’s) to quantitate the BCR-ABL transcript load. The Multiplex RT-PCR and peripheral blood cytogenetics providing specific and sensitive detection of BCR-ABL fusion transcripts and metaphase signal load respectively were used as parallel reference tools to authenticate the q-PCR findings. There was 100% concordance between the multiplex RT-PCR and the q-PCR as every positive RT-PCR assay for a transcript reflected as q-PCR load of above 0% for that transcript. q-PCR also demonstrated a strong Pearson correlation with the cytogenetic response.
Orientation truncated centre learning for deep face recognition
Authors: Zhang Monica M.Y. , Xu Yifang , Wu Huaming
Published: July 2018

Recently, centre loss that aiming to assist Softmax loss with the objectives of both inter‐class dispension and intra‐class compactness simultaneously, has achieved remarkable performance on convolutional neural network‐based face recognition. However, its advantages highly rely on the centre feature assumption, which influences the capacity of the final obtained face features. Inspired by the centre loss approach, a novel Orientation Truncated Centre Learning is proposed, which takes advantage of an orientation truncated centre function to make the centre feature learning have more suitable orientation for deep face recognition. Three metrics are proposed to evaluate how discriminative are the distributions of the learned features for MNIST visualisation. Experimental results on several challenging benchmarks, including fine‐grained labelled faces in the wild (FGLFW), labelled faces in the wild (LFW), YouTube faces (YTF), and benchmark of large‐scale unconstrained face recognition (BLUFR), show that the proposed approach can easily generate more favourable results than several state‐of‐the‐art competitors.
Co‐occurrence matching of local binary patterns for improving visual adaption and its application to smoke recognition
Authors: Yuan Feiniu , Shi Jinting , Xia Xue , Huang Qinghua , Li Xuelong
Published: July 2018

It is challenging to recognize smoke from visual scenes due to large variations of smoke colors, textures and shapes. To improve robustness, we propose a novel feature extraction method based on similarity and dissimilarity matching measures of Local Binary Patterns (LBP). Given two bit‐sequences of an LBP code pair, the similarity and dissimilarity matching measures are defined as the ratios of the 1–1 bitwise matching number to the 0–0 bitwise matching number and the 1–0 number to the 0–1 number, respectively. To capture local code variations, we calculate the measures between LBP codes of a center pixel and its neighbors. Then we compare each measure with its global mean to propose Similarity Matching based Local Binary Patterns (SMLBP) and Dissimilarity Matching based Local Binary Patterns (DMLBP). Since SMLBP and DMLBP extract spatial variations of the 1st order LBP codes, they actually represent the 2nd order variations of pixel values. Furthermore, we adopt different mapping modes and multi‐scale neighborhoods to obtain rotation and scale invariances. Finally, we concatenate the histograms of LBP, SMLBP and DMLBP to generate a feature vector containing 1st and 2nd order information. Experiments show that our method obviously outperforms existing methods.
Low‐rank structured sparse representation and reduced dictionary learning‐based abnormity detection
Authors: Xie Wenbin , Yin Hong , Wang Meini , Shao Yan , Yu Bosi
Published: July 2018

A novel abnormity detection method is presented which combines the low‐rank structured sparse representation and reduced dictionary learning. The multi‐scale three‐dimensional gradient is used as low‐level feature by encoding the spatiotemporal information. A group of reduced sparse dictionaries is learnt by low‐rank approximation based on the structured sparsity property of the video sequence. The contribution of this study is three‐fold: (i) the normal feature clusters can be represented effectively by the reduced dictionaries which are learnt based on the low‐rank nature of the data; (ii) the size of dictionary is determined adaptively by the sparse learning method according to the scene, which makes the representation more compact and efficient; and (iii) the proposed abnormity detection method is of low time complexity and real‐time detection can be obtained. The authors have evaluated the proposed method against the state‐of‐the‐art methods on the public datasets and very promising results have been achieved.
Modelling and simulation of chlorophyll fluorescence from photosystem II as affected by temperature
Authors: Xia Qian , Tan Jinglu , Ji Xunsheng , Jiang Yongnian , Guo Ya
Published: July 2018

Emission of chlorophyll fluorescence (ChlF) from photosystem II (PSII) is affected by both plant status and environmental conditions. In this work, a state space model structure for ChlF from PSII with temperature as a variable model parameter was developed to provide insights into the temperature effects on photosynthesis and greenhouse temperature control. Experiments were carried out at 20, 25, and 30°C to validate the capability and flexibility of the developed model structure. Simulations of ChlF emission were performed for different temperatures. The results demonstrated the effectiveness of the ChlF model structure and the findings are useful for the development of greenhouse temperature control strategies.
Very narrow coronal mass ejections producing solar energetic particles
Authors: Bronarska K. , Wheatland M. S. , Gopalswamy N. , Michalek G.
Published: July 2018

Aims. Our main aim is to study the relationship between low-energy solar particles (energies below 1 MeV) and very narrow coronal mass ejections (“jets” with angular width ≤ 20°).

Methods. For this purpose, we considered 125 very narrow coronal mass ejections (CMEs) from 1999 to 2003 that are potentially associated with low-energy solar particles (LESPs). These events were chosen on the basis of their source location. We studied only very narrow CMEs at the western limb, which are expected to have good magnetic connectivity with Earth.

Results. We found 24 very narrow CMEs associated with energetic particles such as ions (protons and 3He), electrons, or both. We show that arrival times at Earth of energetic particles are consistent with onset times of the respective CMEs, and that in the same time intervals, there are no other potential sources of energetic particles. We also demonstrate statistical differences for the angular width distributions using the Kolmogorov–Smirnov test for angular widths for these 24 events. We consider a coherent sample of jets (mostly originating from boundaries of coronal holes) to identify properties of events that produce solar energetic particles (velocities, widths, and position angles). Our study presents a new approach and result: very narrow CMEs can generate low-energy particles in the vicinity of Earth without other activity on the Sun. The results could be very useful for space weather forecasting.
A mobile catenary power supply system for automotive vehicles
Authors: Maciołek Tadeusz
Published: July 2018

Trolleybus type power supply using a two-pole overhead catenary system has been used for over one hundred years. However, energy demand in this type of road transport is the lowest. The main disadvantage of this type of transport is the lack of flexibility. Road electric vehicles equipped with batteries, which are now more and more often being put into service, allow for autonomous run on the roads without overhead contact wires. Therefore, it is possible to use them in a more flexible manner. The main problem is a limited range of autonomous run and long charge time of batteries. The paper presents a concept consisting in the application of an overhead catenary for supplying electric and hybrid vehicles (including automobiles) when a vehicle is in motion (mobile charging). Electric trucks are equipped with controlled current collectors allowing for connection with an overhead catenary during driving. Application of this solution to automobiles is rather impossible, which prevents them from being supplied directly from a catenary. The basis of the original concept presented in the paper is the creation of automobile convoys supplied via a truck equipped with current collectors. A description of the proposed system and an algorithm of its operation are presented in the paper. The discussed transport system has significant advantages in comparison to completely autonomous electric vehicles: increased range of driving with lower capacity of batteries on board and flexibility of use, longer life-time of batteries, lower energy consumption. The paper compares the proposed system with the currently used ones, which employ charging of automobiles during stops, but also underlines the advantages of the first solution.
Realisation of the mechanical characteristic of a series excited DC machine in the drive with converter – fed induction machine
Authors: Skarpetowski Grzegorz
Published: July 2018

A control algorithm for converter-fed induction machines, which allows the operation of the drive along of mechanical characteristic similar to the characteristic of series-excited direct current machine especially suitable for adhesion traction drives, is presented.
Track insulation verification and measurement
Authors: Bongiorno Jacopo , Mariscotti Andrea
Published: July 2018

Methods for the measurement of track insulation are reviewed pointing out minimum necessary conditions and practical aspects, as well as consistency and repeatability of results. Track configuration, need of electrical sectioning and use of external electrodes or conductive structure are key parameters to determine suitable methods.
Case study of effective current estimation in main circuit of tram vehicle
Authors: Chyła Karol , Urbański Marcin , Sawuła Dominik , Rawicki Stanisław
Published: July 2018

Currently the trams are experiencing the renaissance and more and more Polish cities decide to renew the fleet. New vehicles are usually characterized by high transport capacity, low floor, climate comfort, crash resistance, low energy consumption and low axle loads. Such requirements can only be achieved through optimization in many areas of the vehicle's construction. One of such tasks is the optimal selection of components of the main circuit installation and traction needs. The paper is oriented on the issue of engineering modelling of the effective values of currents flowing in the main circuit and the tramway traction needs circuits. Due to the non-periodic nature of the vehicle traffic loads in urban traffic, the optimal selection of the performance parameters helps in better selection of conductor cross sections, filters and safeguards. A better selection of these components means a reduction of its weight, which is extremely important for meet basic requirements of modern tram vehicles. The paper is intended to gather the experience of authors in this field of knowledge and compares several modelling strategies that the authors use during designing tram vehicles. The elaboration summarizes the results obtained using different modelling strategies, and shows correlation between effective value and selection of components.
Comparison of different tram cars in Poland basing on drive type, rated power and energy consumption
Authors: Kulesz Barbara , Sikora Andrzej
Published: July 2018

Paper deals with tram rolling stock used in Poland nowadays – overview of car types in operation is given. The detailed calculations of energy consumption by a given tram car running over a given route depend in particular on the work carried out (each route is characterized by, among other factors, its profile, length, number of turns, turn radii, number of stops – scheduled or otherwise, number of transferred passengers, number of brakings with possibility of energy recuperation). Results of energy consumption measurements for different car types in Warsaw are provided and analysed.
The latest generation drive for electric buses powered by SiC technology for high energy efficiency
Authors: Biliński Janusz
Published: July 2018

High energy efficiency and increasing the working frequency of the converter will make it possible to minimize the size of the cooling system and reduce energy consumption. The use of the SiC technology in propulsion drives increases the efficiency of the converter by 1÷1.5%. Simultaneously, higher working frequency reduces losses in the traction motor, significantly lowering the cost of the energy consumed by the vehicle. Auxiliary converters using the SiC technology are a new quality. The reduction of weight and size is very significant (ca. 40÷50%). Higher switching frequency reduces the size of magnetic components (ca. 80%), and higher converter efficiency minimizes the size of the cooling system. The overall efficiency of the converter is extremely high (94÷96%). This paper presents comparison of Si and SiC parameters which are important for modern EV solutions. Paper presents also parameters of SiC traction inverter and auxiliary converter, designed and manufactured as state-of-the-art product for modern electric bus.
Evaluation of the efficiency of hybrid drive applications in urban transport system on the example of a medium size city
Authors: Pawełczyk Marek , Szumska Emilia
Published: July 2018

Unconventional drive systems of the urban buses become more and more popular. The reason is clear: reduction of the harmful emissions as well as the fuel consumption reduction. Environmental aspects are becoming of the great importance. Local governments of large cities are “pushing” conventional buses away from city centres, trying to substitute them by the other more environmentally friendly urban vehicles. The goal of the contribution is to present a comparison of the selected types of the urban buses equipped with alternative drive systems under conditions of medium size city. The first part of the paper presents the methodology and construction of urban bus driving cycles prepared for Kielce city (Poland). The next part shows fuel economy and energy consumption obtained from simulation of urban buses powered by conventional diesel engine and hybrid electric drive under the developed driving cycles. The last part presents results of the Total Cost of Ownership (TCO) calculations estimated for selected urban buses.
Analysis of the influence of train timetable on energy consumption on the metro line
Authors: Barański Sławomir , Steczek Marcin
Published: July 2018

The latest technical solutions provide new opportunities for reducing energy consumption in electrified transport systems. The basic solution is to eliminate vehicles based on resistor start-up system and replace them with vehicles equipped with semiconductor based converter propulsion system (choppers and voltage source inverters). This type of drive also allows to recover energy (recuperation) from train braking, which is repeated very often case of metro lines. The problem is to find the receiver for this energy while the vehicle is braking. Large opportunities are also available when using various types of energy storage devices: stationary installed on the side of traction line and mobile ones used on-board the traction vehicles. Choosing the type of energy storage device for operating conditions, their capacity and the location of installation are complex optimization processes. This type of solution involves significant financial input, which reimbursement is spread over a long period of time. Therefore, it seems rational to seek solutions with limited financial outlay. This paper presents a solution analysis of adjusting the timetable and timeshifts between vehicle streams on the metro line to increase the efficiency of energy recovery of regenerative braking vehicles. This operation will reduce the amount of energy consumption by vehicles from the traction substations. The results presented in the paper were obtained by computer simulation of operation on the first line of the Warsaw subway, assuming that there was no energy storage devices and traction substations were operating without recuperation of the energy to the power system.
Electrified lines entering tunnels in Poland, safety aspects of the running with fire
Authors: Pawlik Marek
Published: July 2018

Potential fire on board of the passenger train creates risk for passengers health and passengers life. Using non-flammable materials for producing Electric Multiple Units (EMUs) is not considered to be sufficient as passengers are carrying different types of materials as their luggage and belongings. In case of fire on board of the train, the EMU should stop in a place which is appropriate for passengers evacuation and fire fighting. Not all places along railway lines are considered to be appropriate for such purpose. Especially stopping in tunnels is considered inappropriate. Meanwhile the amount of tunnels on the Polish railway network is growing significantly. This requires application of the Technical Specification for Interoperability regarding Safety in Railway Tunnels (TSI SRT) and set of fire standards EN 45545. Using those requirements is associated with putting tunnels and rolling stock into service under railway interoperability directive 2008/57/WE. Additional analyse is however necessary from operational safety point of view due to growing amount of tunnels and growing diversity of rolling stock. Paper proposes conducting risk analyse in accordance with common safety method for risk evaluation and assessment based on a dedicated European Standard EN 50533 which defines requirements regarding running capability in case of fire on board of the rolling stock. Paper analyses applicability of that approach for group of tunnels and rolling stock fleet comprising different types of rolling stock including Electric Multiple Units.
Integrated power supply system for station equipment of rail traffic control
Authors: Mielnik Ryszard , Wróbel Zofia
Published: July 2018

Railway Traffic Control Systems (RTCS) provide a safe, reliable and efficient movement of rolling stock on railway networks. RTCSs are classified as critical process systems. The power supply system is required to provide a high level of power reliability so that a station equipment of an RTCS safely executes the rail traffic process. The article describes typical solutions of power supply of station equipment of RTCSs. Analysis of these solutions led to the development of assumptions and structures for the integrated power supply system of station equipment. Useful tools for the formal modeling of such systems can be Petri Nets. These nets are a graphical and formal tool for modeling, formal analysis, and design of discrete event systems. The basic element of the integrated power system which is described in the article is the Automatic Reserve Switching system (ARS system). The ARS controller Marked Petri Net (ARS controller MPN) that has been developed by the authors is presented here. The net was subject to reduction resulting in an ARS controller hierarchical simplified MPN. The article also presents the practical application of the ARS controller built using the hardware platform and graphical programming environment LabView National Instruments (NI).
The influence of coefficients for the terms of a controller on generation of braking curve
Authors: Anuszczyk Jan , Gocek Andrzej
Published: July 2018

This paper presents the theory about generating a braking curve and the analysis of the influence of the braking controller parameters on generation of the braking curve of the train. It has been demonstrated that the developed algorithms can be used to verify the effectiveness of the braking controller and the adjustment of the terms, and the change of these algorithms affects the shape of the generated braking curve of the train. The developed simulator cooperating with braking control system, which is reflecting the influence of braking function of the applied system used in the subway, has been analysed in terms of the impact of the parameters on the generation of braking curve. The outcomes has been presented and commented. Authors have also shown the results of the tests in the terms of an impact of a selected controller on the generation of braking curve.
Technical parameters of high speed lines as the determinant for selection of rolling stock
Authors: Raczyński Jan
Published: July 2018

Choosing a high-speed rail vehicle depends on many factors. On the one hand, there are requirements for ensuring the quality of service for passengers, on the other hand, there are constraints resulting from the parameters of available infrastructure. Also a relation of the benefit and financial costs associated with the purchase and the operation of rolling stock is essential. Technical characteristics of vehicles selected for operating a particular system is a compromise between the three groups of requirements. In this article technical parameters of railway infrastructure and rolling stock are classified and then analysed from the TSI requirements point of view.
Update mHealth
Authors: Becker Stefan , Jahn Michael , Pramann Oliver , Hasenfuß Gerd , Budde Clemens , Halleck Fabian , Albrecht Urs-Vito
Published: July 2018

Im Gesundheitswesen kommen immer mehr Apps auf den Markt und im klinischen Alltag zum Einsatz. Unabhängig davon, ob es sich um ein Medizinprodukt handelt oder
nicht, besteht bei einer Fehlfunktion im Schadensfall unter Umständen ein erhebliches Haftungsrisiko für den Arzt. Trifft man vor der Anwendung gezielte
Vorkehrungen, lässt sich dieses minimieren. Ein neues Filtersystem für Apps im Bereich der Inneren Medizin soll zudem für eine bessere Orientierung in den
App-Stores bieten.
Imaging of Sacral Stress and Insufficiency Fractures
Authors: Spiegl Ulrich , Schnake Klaus , Osterhoff Georg , Scheyerer Max , Ullrich Bernhard , Bula Philipp , Siekmann Holger
Published: July 2018

Sakrumfrakturen, die ohne adäquates Trauma entstanden sind, werden in Insuffizienzfrakturen und Stressfrakturen eingeteilt. Während Insuffizienzfrakturen bei physiologischer Belastung meist auf dem Boden einer relevanten Osteoporose entstehen, beruhen Stressfrakturen auf einer mechanischen Überlastung. Der vordere Beckenring ist regelmäßig beteiligt. Aufgrund des fehlenden bzw. niederenergetischen Unfallhergangs wird die korrekte Diagnose oft verspätet gestellt. Demzufolge war es das Ziel der AG Osteoporotische Frakturen der Sektion Wirbelsäule der DGOU, die einzelnen bildgebenden Verfahren zur korrekten, schnellen und kosteneffektiven Diagnostik vorzustellen. Zur Diagnosesicherung sollte neben der konventionell radiologischen Diagnostik zeitnah eine Schnittbildgebung in die Wege geleitet werden. Mittels CT kann die Frakturmorphologie am besten beurteilt werden, wodurch potenzielle Instabilitätszeichen der Verletzung erkannt werden können. Die MRT kann aufgrund der hohen Sensitivität bei fehlendem Frakturnachweis im CT, bei jungen Patienten und unklaren Situationen zusätzliche wichtige Informationen liefern. Im Falle einer Kontraindikation für das MRT stellen nuklearmedizinische Untersuchungen eine gute Alternative dar.
Maschinen statt Menschen
Authors: Alscher Mark Dominik
Published: July 2018

Die Praxis der Medizin sieht sich aktuell großen Herausforderungen gegenüber. Insbesondere die Aspekte der „e-Health“ bieten einerseits Chancen, aber auch
Herausforderungen. Um Exzellenz in der Medizin zu erreichen, ist eine praktische Erfahrungsbasis von 10 000 Stunden notwendig. Heutzutage wird dies aufgrund
mehrerer Faktoren nicht mehr erreicht. Die Exzellenz in der Medizin, welche häufig auch auf Intuition beruht, wird damit verschwinden, wenn wir nicht durch
digitale Lösungen andere Möglichkeiten finden. Eine davon besteht in „Clinical-decision-support“-Systemen. In der Maschine-Mensch-Partnerschaft wird in naher
Zukunft die Exzellenz aufrecht zu erhalten sein.
Conjugate Alkynylation of Electrophilic Double Bonds. From Regioselectivity to Enantioselectivity
Authors: Blay Gonzalo , Pedro José , Sanz-Marco Amparo
Published: July 2018

This review surveys the historical efforts addressed toward the development of the conjugate alkynylation reaction. The regio- and enantioselective conjugate alkynylation of electron-deficient double bonds, most commonly unsaturated carbonyl compounds, has been an elusive reaction for a long time. Intensive research during the last decades has resulted in the identification of a number of effective reagents and catalysts to perform this reaction. Non-stereoselective conjugate alkynylation of unsaturated carbonyl compounds was first achieved by using preformed alkynyl organometallics and later with terminal alkynes under catalytic conditions. These methods paved the way for the development of enantioselective procedures. After initial methods requiring stoichiometric amounts of chiral material, the findings by Corey on Ni-catalyzed addition of alkynylalanes and, particularly, by Carreira on Cu-catalyzed addition of terminal alkynes boosted the research on the development other asymmetric procedures catalyzed by Cu, Zn, Rh, Co, Ru and Pd complexes. The alkynylation of electrophilic alkenes conjugated with groups other than carbonyl and the alkynylation of extended conjugated systems are also discussed in the last part of this review.

1 Introduction

2 Non-Stereoselective Conjugate Alkynylation of α,β-Unsaturated Carbonyl Compounds

3 Enantioselective Conjugate Alkynylation of α,β-Unsaturated Carbonyl Compounds

4 Non-Stereoselective and Enantioselective Alkynylation of Other Electrophilic Alkenes

5 γ-Alkynylation of α,β-Unsaturated Amides and δ-Alkynylation of Electrophilic Dienes

6 Alternative Enantioselective Procedures

7 Conclusion and Outlook
Buttocks Hard as Rocks: Not Wanted after Aortic Dissection Repair
Authors: Cameron-Gagné Maude , Bédard Luc , Lafrenière-Bessi Valérie , Lévesque Marie-Hélène , Dagenais François , Langevin Stéphan , Laflamme Maxime , Voisine Pierre , Jacques Frédéric
Published: July 2018

The authors report the case of a patient developing a gluteal compartment syndrome after DeBakey type I dissection repair. Prompt recognition and treatment led to successful results. The surgical approach to the gluteal compartment is described.
Epigenetics in Ascending Thoracic Aortic Aneurysm and Dissection
Authors: Boileau Adeline , Lindsay Mark , Michel Jean-Baptiste , Devaux Yvan
Published: July 2018

Thoracic aortic aneurysm (TAA) is an asymptomatic and progressive dilatation of the thoracic aorta. Ascending aortic dissection (AAD) is an acute intraparietal tear, occurring or not on a pre-existing dilatation. AAD is a condition associated with a poor prognosis and a high mortality rate. TAA and AAD share common etiology as monogenic diseases linked to transforming growth factor β signaling pathway, extracellular matrix defect, or smooth muscle cell protein mutations. They feature a complex pathogenesis including loss of smooth muscle cells, altered phenotype, and extracellular matrix degradation in aortic media layer. A better knowledge of the mechanisms responsible for TAA progression and AAD occurrence is needed to improve healthcare, nowadays mainly consisting of aortic open surgery or endovascular replacement. Recent breakthrough discoveries allowed a deeper characterization of the mechanisms of gene regulation. Since alteration in gene expression has been linked to TAA and AAD, it is conceivable that a better knowledge of the causes of this alteration may lead to novel theranostic approaches. In this review article, the authors will focus on epigenetic regulation of gene expression, including the role of histone methylation and acetylation, deoxyribonucleic acid methylation, and noncoding ribonucleic acids in the pathogenesis of TAA and AAD. They will provide a translational perspective, presenting recent data that motivate the evaluation of the potential of epigenetics to diagnose TAA and prevent AAD.
Protein C Osaka 10 with Aberrant Propeptide Processing: Loss of Anticoagulant Activity Due to an Amino Acid Substitution in the Protein C Precursor
Authors: Miyata Toshiyuki , Zheng Yan-Zhen , Sakata Toshiyuki , Kato Hisao
Published: July 2018

We studied the molecular basis of protein C deficiency in a family with a history of thromboembolic disease. An approximately 50% reduction in anticoagulant activity despite normal levels of protein C amidolytic activity and antigen was detected in plasma from the proband. All the exons and intron/exon junctions of the protein C gene were studied using a strategy that combined polymerase chain reaction amplification with DNA sequencing of the amplified fragments. We identified a C-to-A change at nucleotide number 1387 of the protein C gene in the proband and his mother, and this mutant was designated protein C Osaka 10. The C-to-A change resulted in the substitution of Ser for Arg at position -1, which is the processing protease cleavage site. The mutant protein C was partially purified from plasma of the patient’s mother using barium adsorption followed by ion-exchange column chromatography. It eluted at the same sodium chloride concentration as normal protein C, and thus γ-carboxylation of the mutant protein appeared to be normal. The apparent molecular weight of this mutant protein C was the same as that of the normal protein on immunoblotting. Amino-terminal sequence analysis showed that the light chain of the mutant protein C had an additional Ser at position -1. Thus, the loss of anticoagulant activity of protein C Osaka 10 can be explained by alteration of the conformation of the Gla domain by the additional Ser in the mutant molecule.
Studies on the Haemostatic Defect in a Complicated Syndrome
Authors: Stormorken H , Holmsen H , Sund R , Sakariassen K S , Hovig T , Jellum E , Solum N O
Published: July 2018

The Stormorken syndrome is a multifacetted syndrome including a bleeding tendency. No deviations were found in the coagulation- or fibrinolytic systems. Platelet number was low normal, and size abnormal, whereas EM findings were unremarkable. Survival time was half normal. Clot retraction was initially rapid, but clearly decreased, whereas prothrombin consumption was also initially rapid, but complete. Membrane GP’s were normal, so was AA metabolism, PI-cycle, granule storage and secretion, and c-AMP function, whereas 5-HT uptake and storage was decreased. Optical platelet aggregation was low normal with all physiological agonists. The only clearly abnormal finding was that coagulant activity was present on non stimulated platelets at the same level as kaolin-stimulated normal platelets. This indicated a platelet abnormality which should lead to a thrombogenic, not to a haemorrhagic trait. This paradox may have its origin in rheology, because when challenged with in vivo shear rates in an ex vivo perfusion chamber, platelet cohesion was abnormally low. Further studies to better delineate the membrane abnormality are underway.
Identification and Genetic Analysis of a Common Molecular Variant of Histidine-rich Glycoprotein with a Difference of 2KD in Apparent Molecular Weight
Authors: Hennis B C , van Boheemen P A , Wakabayashi S , Koide T , Hoffmann J J M L , Klevit P , Dooijewaard G , Jansen J G , Kluft C
Published: July 2018

Two forms of histidine-rich glycoprotein (HRG) were detected on SDS-PAGE by silver staining and immunoblotting after isolation of the protein from pooled plasma using immuno-affinity chromatography followed by chromatography with heparin-Sepharose. Both forms were single-chain molecules and the apparent molecular weights of form 1 and form 2 were 77 kD and 75 kD respectively. Mendelian inheritance of both HRG forms was observed in four families with 24 informative meioses, strongly suggesting that the two forms are encoded by different alleles. The frequency of form 1 and form 2 in a group of 36 individuals was 0.35 and 0.65 respectively.

The difference between the two molecular variants was studied by direct sequence analysis of amplified exons of the HRG gene from 6 individuals who were homozygous either for form 1 or form 2. Five amino acid polymorphisms in three different exons were observed: Ile/Thr in exon 4; Pro/Ser in exon 5; His/Arg, Arg/Cys and Asn/Ile in exon 7. Analysis of these polymorphisms in 20 volunteers showed that only the Pro/Ser polymorphism at position 186 in exon 5 was coupled to the form of the HRG protein. Ser was found in form 1 and Pro in form 2. The presence of Ser at position 186 introduces a consensus sequence for a N-glycosylation site (Asn-X-Ser/Thr). By removing N-linked sugars with N-glycanase, it could be demonstrated that the difference between the two forms of HRG is caused by an extra carbohydrate group at Asn 184 in form 1.
Uptake, Internalization and Degradation of the Novel Plasminogen Activator Reteplase (BM 06.022) in the Rat
Authors: Kuiper J , van de Bilt H , Martin U , van Berkel Th J C
Published: July 2018

The catabolism of the novel plasminogen activator reteplase (BM 06.022) was described. For this purpose BM 06.022 was radiolabelled with l25I or with the accumulating label l25I-tyramine cellobiose (l25I-TC).

BM 06.022 was injected at a pharmacological dose of 380 μg/kg b.w. and it was cleared from the plasma in a biphasic manner with a half-life of about 1 min in the α-phase and t1/2of 20-28 min in the β-phase. 28% and 72% of the injected dose was cleared in the α-phase and β-phase, respectively. Initially liver, kidneys, skin, bones, lungs, spleen, and muscles contributed mainly to the plasma clearance. Only liver and the kidneys, however, were responsible for the uptake and subsequent degradation of BM 06.022 and contributed for 75% to the catabolism of BM 06.022. BM 06.022 was degraded in the lysosomal compartment of both organs. Parenchymal liver cells were responsible for 70% of the liver uptake of BM 06.022. BM 06.022 associated rapidly to isolated rat parenchymal liver cells and was subsequently degraded in the lysosomal compartment of these cells. BM 06.022 bound with low-affinity to the parenchymal liver cells (550 nM) and the binding of BM 06.022 could be displaced by t-PA (IC50 5.6 nM), indicating that the low-density lipoprotein receptor-related protein (LRP) could be involved in the binding of BM 06.022. GST-RAP, which is an inhibitor of LRP, could in vivo significantly inhibit the uptake of BM 06.022 in the liver.

It is concluded that BM 06.022 is metabolized primarily in the liver and the kidneys. These organs take up and degrade BM 06.022 in the lysosomes. The uptake mechanism of BM 06.022 in the kidneys is unknown, while LRP is responsible for a low-affinity binding and uptake of BM 06.022 in parenchymal liver cells.
Effects of an Epoxymethano Stable Analogue of Prostaglandin Endoperoxides (U-46619) on Human Platelets
Authors: di Minno G , Bertelé V , Bianchi L , Barbieri B , Cerletti C , Dejana E , de Gaetano G , Silver M J
Published: July 2018

U-46619 is a stable epoxymethano analogue of cyclic endoperoxide PGH2. We studied platelet aggregation, 14C-5HT release, LDH extrusion and prostaglandin and thromboxane production induced by this compound in platelet-rich plasma samples from 15 healthy volunteers. Each subject was tested both before and 90 min after aspirin (500 mg) ingestion. The threshold aggregating concentration (TAC) of U-46619 ranged between 0.18 and 0.90 µM. Aggregation was maximal between 40 and 60 min after venipuncture and was concentration-dependent. At concentrations below the TAC, U-46619 induced primary reversible aggregation with minimal 14C-5HT release. At TAC or higher concentrations aggregation and release proceded as parallel events. Neither prostaglandin or thromboxane production nor LDH loss could be detected in any of the situations tested. Aspirin ingestion did not modify the pattern of platelet responses. In unstirred, not aggregated platelet samples 14C-5HT release by U-46619 occurred to a similar extent as in stirred, aggregated platelet samples. Addition to citrated PRP of 0.3 mM Na2 EDTA blocked both aggregation and release induced by U-46619. This compound, however, aggregated washed platelets resuspended in Ca++-free-tyrode-albumin containing fibrinogen. The mechanism by which U-46619 activates platelets differs from that of all other common aggregating agents.
Induction of Human Factor VIII Inhibitors in Rats by Immunization with Human Recombinant Factor VIII: a Small Animal Model for Humans with High Responder Inhibitor Phenotype
Authors: Jarvis M A , Levin L G , Harrison J A , DePianto D J , Suzuki C M , Ziaja C L , Brown J E , Jolly K W , Reisner H M , Abidgaard C F , Powell J S
Published: July 2018

Hemophilia A is a clotting disorder that is due to reduced or absent coagulation factor VIII (FVIII) activity. In approximately 25% of people with severe hemophilia A, standard treatment with intravenous plasma-derived or recombinant FVIII (rFVIII) induces anti-FVIII antibodies that inhibit FVIII activity (inhibitors). We describe the development of a rat model to study the formation of inhibitors. Immunization of rats with human rFVIII in adjuvant induced an anti-human rFVIII antibody response characteristic of an anti-FVIII inhibitor response in hemophilia A patients. The rats exhibited a rapid, polyclonal secondary antibody response to human rFVIII. These antibodies were reactive against epitopes located in the heavy and light chains. All the rFVIII-immunized rats developed antibodies against the FVIII C2 domain, a region of major reactivity in hemophilia A patients with inhibitors. Furthermore, competition ELISAs demonstrated that rat and human anti-FVIII antibodies recognized identical or overlapping epitopes of the FVIII molecule. The rat anti-FVIII antibodies also functioned as human FVIII inhibitors with titers ranging from 120 to 2048 Bethesda Units (B.U.). We propose that this rat model may be useful to investigate immune responses to FVIII and may lead to better therapies for FVIII inhibitors.
Retinoids Induce t-PA Synthesis by C6 Glioma Cells -Role in Tumoral Haemorrhagic Necrosis
Authors: Pernod Gilles , Amalfltano Guy , Le Magueresse Brigitte , Berger Francois , Polack Benolt , Kolodie Lucien
Published: July 2018

Treatment of rat C6 glioma with high doses of 13 cis-retinoic acid (cRA) was responsible for death related to haemorrhagic necrosis localized to the tumor. Our aim was to explore this adverse effect of retinoid treatment. We show that cRA-treated C6 glioma at 25 mg/kg/day for 18 days exhibits in vivo an increased t-PA activity, which is responsible for a localized tumor fibrinolytic activity. Production of t-PA is supported by specific enhancement of gene expression, as was shown by the increase in t-PA mRNA (X 2.3). This production is a direct effect of cRA when treating the tumor, since tumor cells themself do not produce enough t-PA and treatment of control rats does not increase the t-PA level. t-PA production by rat C6 glioma is in vivo related to the specific synthesis of t-PA by the C6 cell-line. The stimulation of C6 cell-line by cRA in vitro is dose-dependent and reached a maximum for 3 and 30 |iM at the 72nd h. So cRA-treated C6 glioma cells produce t-PA which appears to be the major species associated with the fibrinolytic activity-induced intra-tumoral haemorrhage after exposure to retinoid treatment.
Platelet-derived Microvesicles in Thrombotic Thrombocytopenic Purpura and Hemolytic Uremic Syndrome
Authors: Galli Monica , Grassi Anna , Barbui Tiziano
Published: July 2018

Thrombotic thrombocytopenic purpura (TTP) and the related hemolytic uremic syndrome (HUS) are disorders characterized by thrombocytopenia, microangiopathic hemolytic anemia, a variable degree of impairment of renal function and fluctuating neurological symptoms, which are thought to be due to platelet activation and subsequent formation of thrombi in the microcirculation. Since platelet activation is accompanied by the generation of microvesicles (PMPs), we determined their presence in patients with TTP and HUS by flow cytometry. The analysis was performed in whole blood, using FITC-conjugated monoclonal antibodies (CD 42b and/or CD 61a). PMPs were discriminated from platelets on the basis of size and fluorescence profiles. Their levels in 21 normal controls ranged between 2.4% and 9.4% (mean ± SD: 5.2 ± 1.99%). No correlations were found with platelet number. PMPs were then evaluted in 13 patients with TTP and 2 cases of HUS. In all patients they were found higher than in controls, ranging from 11.0 to 91.1% (45.0 ± 26.0%; p = 0.0001 vs controls). PMPs were serially measured in patients with TTP: at diagnosis a correlation between PMPs and platelet number was found (R^2 = 0.669) and the time-course showed that the improvement of both microangiopathy and clinical manifestations of cerebral and renal involvement was accompanied by a progressive normalization of PMP levels and platelet count.

PMP levels were measured also in patients suffering from other forms of thrombocytopenia: they were 17 patients with idiopathic thrombocytopenic purpura and 10 patients with acute leukemias and severe thrombocytopenia during the aplastic phase following chemotherapy. PMP ranges were: 2.0−79.6% (21.6 ± 20.8%; p = 0.001 vs controls) and 4.6−12.5% (8.8 ± 2.4%; p = 0.0001 vs controls), respectively. No correlations were found between platelet number and the absolute number of PMPs in these 2 groups of patients.

These findings show that increased levels of PMPs may be found in peripheral thrombocytopenias and suggest that their presence may be clinically relevant, particularly in the microangiopathic forms.
Characterization Of The In Vitro “Factor VIII Bypassing Activity”
Authors: Aronson D L , Bagley J
Published: July 2018

The in vitro correction of the prolonged APTT of hemophilic plasma has been ascribed to an uncharacterized entity “Factor VIII Bypassing Activity.” Such products also correct the prolonged APTT plasma deficient in Factor IX, Factor X and Factor XII, but not of Factor V deficient plasma. Correction of the APTT in Factor VIII deficient plasma by early stage coagulants such as Factor XIIa, Kallikrein and Factor IXa is minimal. These results indicate that this in vitro activity acts at the level of either the activation of Factor X or the activation of prothrombin.

A coagulant has been prepared from serum by barium precipitation, heparin-agarose, DEAE cellulose and high pressure liquid chromatography (HPLC). The in vitro coagulant properties are similar to “activated” prothrombin complex (Autoplex) and the biologic and chemical properties are identical to activated Factor X.

Infusion of the partially purified serum coagulant into normal dogs was well tolerated and, in contrast to Factor IX concentrates, gave no signs of DIC. Infusion into bleeding hemophilic dogs had no hemostatic effect. It is concluded that a major portion of the in vitro potency of activated prothrombin concentrates is due to activated Factor X, a material which when infused has no in vivo hemostatic effect.

Acknowledgments - The authors gratefully acknowledge the studies of Dr. Henry Kingdon in hemophilic dogs.
The Development Of Monoclonal Antibodies To Factor VIII Related Antigen (VIIIRAG)
Authors: Thomas J E , Furlong R A , Giddings J C , Peake I R , Bloom A L
Published: July 2018

A human VIIIRAg rich fraction was prepared from human factor VIII concentrate by gel chromatography on Sepharose CL6B to give 40 u/ml VIIIRAg and 0.06 u/ml factor VIII clotting antigen (VIIICAg). Balb/c mice were immunised with this fraction (1-2 u VIIIRAg per mouse) and polyclonal antibody to VIIIRAg was detected in the serum of the mice by conventional immunodiffusion and by a specially developed immunoradlometric test (IRMT). This test utilised polystyrene tubes coated with polyclonal (sheep) antibody to VIIIRAg which were then incubated with a source of human VIIIRAg (pooled normal plasma). After incubation with mouse anti human VIIIRAg the bound mouse immunoglobulin was detected by binding of 125I labelled rabbit anti mouse IgG. This was prepared from commercial rabbit anti mouse IgG by immunoadsorption and elution from immobilised mouse immunoglobulin. Using the IRMT a monoclonal antibody to VIIIRAg was detectable at a dilution of 5 × 105. Mice with the highest serum antibody titre were selected, hyper- immunised and used as spleen donors. Spleen cells were harvested, fused with homologous NS-1 myeloma cells and cultured in HAT selective medium. Hybrids producing specific antibody to VIIIRAg were detected by the IRMT and cloned by the limiting dilution method. Antibodies were tested for their activity against VIIIRAg and factor VIII related ristocetin cofactor activity, and also for any activity against VIIICAg and procoagulant factor VIII.