bluuebunny/crossref_metadata_2025 huggingface dataset:
Software defined wireless sensor networks and efficient congestion control
Authors: Letswamotse Babedi Betty , Malekian Reza , Chen Chi‐Yuan , Modieginyane Kgotlaetsile Mathews
Published: August 2018

To achieve greater performance in computing networks, a setup of critical computing aspects that ensures efficient network operation needs to be implemented. One of these computing aspects is quality of service (QoS). QoS capable of networking allows efficient control of traffic, especially for network critical data. However, to achieve this in wireless sensor networks (WSNs) is a serious challenge, since these technologies have computing limitations. It is even difficult to manage networking resources with ease in these types of technologies, due to their communication, processing and memory limitations. Even though this is the case with WSNs, they have been largely used in monitoring/detection systems, and by this proving their application importance. In this study, a resource‐aware OpenFlow‐based active network management QoS scheme that uses software defined networking (SDN) strategies is proposed and implemented to apply QoS requirements for managing traffic congestion in WSNs. This scheme uses SDN programmability strategies to apply network QoS requirements and perform traffic load balancing to ensure congestion control in software defined WSNs. The experimental results show that the developed scheme is able to provide congestion avoidance within the network. It also allows opportunities to implement flexible QoS requirements based on the system's traffic state.
Transformer‐less dynamic voltage restorer based on a three‐leg ac/ac converter
Authors: Zhou Min , Sun Yao , Su Mei , Li Xing , Lin Jianheng , Liang Jian , Liu Yonglu
Published: August 2018

A transformer‐less dynamic voltage restorer (DVR) with bipolar voltage gain capability is proposed in this study. The DVR is formed by a three‐leg ac/ac converter with its output capacitor in series with the transmission line. Since the energy used for voltage compensation is obtained from the grid, long‐time voltage disturbances can be compensated without using bulky energy storage elements. As a result, the proposed DVR has the features of compact structure, light weight, and low cost. Moreover, it also has a high reliability as the commutation problem is avoided by adopting the proposed modulation strategy. A detailed analysis of the topology structure and operation principle is given, followed by the developed control method. Finally, simulations and experimental results are presented to verify the validity of the DVR.
Preyssler‐based nanocomposite as a magnetic photocatalyst: synthesis, characterisation and its photocatalytic activity for decolourisation of rhodamine B
Authors: Bamoharram Fatemeh F. , Mozhdehi AmirMohammad , Radfar Azadeh , Shaker Mohammad , Mallaeke Hassan , Sharifi Amir Hossein
Published: August 2018

In this work, the authors prepared a novel magnetic photocatalyst by grafting of Preyssler‐type polyoxometalate, H14 [NaP5W30O110] onto Fe3O4 nanoparticles via an internal layer of silver nanoparticles. The obtained nanocomposite has been characterised by electron dispersive X‐ray, transmission electron microscopy and scanning electron microscopy. The activity of the synthesised nanomagnetic photocatalyst was tested by the photocatalytic decolourisation of rhodamine B under UV light irradiation in the study's designed reactor. It was found that, compared to pure Preyssler, decolourisation of rhodamine B was occurred four times faster using the synthesised magnetic nanocomposite with easy separation. The magnetic nanocatalyst was separated after ending the reaction and recycled. It just showed 2–3% decrease in catalytic activity after four recycling.
Synthesis, characterisation, and antimicrobial activity of ZnO‐based nanocomposites
Authors: Faraji Naser , Hajimahdi Zahra
Published: August 2018

In this study, ZnO‐based nanocomposites including ZnO/CuO (S1), ZnO/MnO (S2), and ZnO/MnO/CuO (S3), were synthesised. S1, S2, and S3 were characterised through Fourier transform infrared (FTIR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X‐ray spectroscopy (EDS) techniques. Also, the antimicrobial property of the samples was examined against both Gram‐positive Staphylococcus aureus and Gram‐negative Escherichia coli through the colony forming count method. FTIR analysis confirmed the presence of Zn–O, Mn–O, and Cu–O in the samples. The crystalline structure of the sample was analysed by XRD. The surface morphology of the prepared compounds was studied with SEM images. EDS technique was employed for ensuring the presence of Zn, Mn, and Cu elements in the samples. The results clearly showed S1, S2, and S3 had high‐antimicrobial activity especially for S3.
The orientation of galaxy pairs with filamentary structures: dependence on morphology
Authors: Mesa Valeria , Duplancic Fernanda , Alonso Sol , Muñoz Jofré Maria Rosa , Coldwell Georgina , Lambas Diego G.
Published: August 2018

Aims. With the aim of performing an analysis of the orientations of galaxy pair systems with respect to the underlying large-scale structure, we study the alignment between the axis connecting the pair galaxies and the host cosmic filament where the pair resides. In addition, we analyze the dependence of the amplitude of the alignment on the morphology of pair members as well as filament properties.

Methods. We build a galaxy pair catalog requiring rp < 100 h−1 kpc and ΔV < 500 km s−1 within redshift z < 0.1 from the Sloan Digital Sky Survey (SDSS). We divided the galaxy pair catalog taking into account the morphological classification by defining three pair categories composed by elliptical–elliptical (E–E), elliptical–spiral (E–S) and spiral–spiral (S–S) galaxies. We use a previously defined catalog of filaments obtained from SDSS and we select pairs located closer than 1 h−1 Mpc to the filament spine, which are considered as members of filaments. For these pairs, we calculate the relative angle between the axis connecting each galaxy, and the direction defined by the spine of the parent filament.

Results. We find a statistically significant alignment signal between the pair axes and the spine of the host filaments consistent with a relative excess of ∼15% aligned pairs. We obtain that pairs composed by elliptical galaxies exhibit a stronger alignment, showing a higher alignment signal for pairs closer than 200 h−1 kpc to the filament spine. In addition, we find that the aligned pairs are associated with luminous host filaments populated with a high fraction of elliptical galaxies. The findings of this work show that large-scale structures play a fundamental role in driving galactic anisotropic accretion as induced by galaxy pairs exhibiting a preferred alignment along the filament direction.
Étude de la composition minérale et des teneurs en protéines et en matières grasses de huit variétés de sésame (Sesamum indicum L.) introduites au Sénégal pour un criblage variétal
Authors: Sene Birama , Sarr Fallou , Diouf Diegane , Kane Amadou , Traore Djibril
Published: August 2018

Huit variétés de sésame (EF153, EF147, LC162, LC164, HB168, 32-15, 38-1-7 et Birkan) qui, selon le Centre d’Étude Régional pour l’Amélioration de l’Adaptation à la Sécheresse (CERAAS), sont les mieux appréciées sur le plan agro-morphologique, ont fait l’objet de cette étude. Les teneurs en protéines, en matières grasses et en éléments minéraux de chacune d’elles ont été déterminées. L’étude des éléments minéraux a porté sur le calcium, le phosphore, le magnésium, le fer et le zinc. Les résultats ont montré que, pour les huit variétés de sésame étudiées, les teneurs en protéines varient de 22,59 % à 29,37 % tandis que celles en matières grasses s’établissent dans une fourchette de 48,65 % à 52,45 %. L’étude montre aussi que toutes les variétés sont riches en éléments minéraux. Cependant, le calcium demeure l’élément le plus important dans toutes les variétés étudiées, suivi du phosphore, du magnésium, du fer et du zinc. Les meilleures teneurs minérales obtenues, pour tous les minéraux étudiés, sont avec la variété 38-1-7 : magnésium 455,04 mg/100 g ; phosphore 711,17 mg/100 g ; calcium 973,22 mg/100 g de ; fer 10,86 mg/100 g et le zinc 7,88 mg/100 g. L’étude statistique des teneurs en protéines, en matières grasses et en composition minérale des variétés a permis d’identifier trois variétés plus appréciées, mais aussi d’indiquer leurs domaines potentiels d’utilisation. Ainsi, les variétés LC162 et 38-1-7 pourraient être utilisées respectivement comme additifs en protéines et en éléments minéraux dans les aliments destinés aux enfants. Quant à la variété EF147, elle pourrait être recommandée pour la consommation d’huile.
Adulte Lumbalskoliose – ändert sich die Therapie mit zunehmendem Alter?
Authors: Quante Markus
Published: August 2018

Patienten mit adulter lumbaler Skoliose werden meist in der 2. Lebenshälfte zunehmend therapiebedürftig. Neben konservativen und interventionellen Maßnahmen können mitunter sehr umfangreiche operative Therapien indiziert werden. Diese Arbeit befasst sich mit den Möglichkeiten, die Therapiestratifizierung auch altersabhängig zu betreiben. Hierzu werden 3 biologische Altersgruppen (jung, mittel, alt) definiert und in therapeutischer Hinsicht gegeneinander abgegrenzt.
A novel device for intracolonoscopy cleansing of inadequately prepared colonoscopy patients: a feasibility study
Authors: van Keulen Kelly , Neumann Helmut , Schattenberg Jörn , van Esch Aura , Kievit Wietske , Spaander Manon , Siersema Peter
Published: August 2018

Background The importance of high quality preprocedural bowel preparation is widely acknowledged, but suboptimal bowel cleansing still occurs in up to 20 % of all colonoscopy patients. The aim of this study was to evaluate the performance of a novel intraprocedural cleaning device for cleaning poorly prepared colons.

Methods This multicenter feasibility study included patients aged 18 – 75 years who were referred for colonoscopy. Intraprocedural cleaning was performed in patients after a limited preprocedural bowel preparation regimen (2 days of dietary restrictions and 2 × 10 mg bisacodyl). The primary outcome was the proportion of adequately prepared patients (Boston Bowel Preparation scale [BBPS] ≥ 2 in each segment) before and after segmental washing with the new device. Secondary outcomes included: cecal intubation rate, procedure time, system usability, patient satisfaction, and safety.

Results 47 patients (42.6 % male), with a median age of 61 years (interquartile range [IQR] 46 – 67 years), were included at three clinical sites. Cecal intubation was achieved in 46/47 patients (97.9 %). The cleaning device significantly improved the proportion of patients with adequate bowel cleansing (from 19.1 % to 97.9 %; P < 0.001) and median BBPS score (from 3.0 [IQR 0.0 – 5.0] to 9.0 [IQR 8.0 – 9.0]). Median cecal intubation time and total procedure time were 16.5 minutes (IQR 9.0−28.3) and 34.0 minutes (IQR 25.0 – 42.8), respectively. Physicians were satisfied with the ease of use of the device and it was well tolerated by patients. No severe adverse events occurred during the study period.

Conclusions This feasibility study suggests that the intraprocedural cleaning device appears to be safe and effective in cleaning poorly prepared colons to an adequate level, allowing a thorough colorectal examination.
Rescue Adjuvant Vaginal Progesterone May Improve Outcomes in Cervical Cerclage Failure
Authors: Roman Alina , Da Silva Costa Fabricio , Araujo Júnior Edward , Sheehan Penelope
Published: August 2018

Introduction Aim of the study was to evaluate the effect of rescue adjuvant vaginal progesterone in women with ongoing, transvaginal ultrasound (TVUS)-confirmed cervical shortening despite cervical cerclage.

Materials and Methods A retrospective case control study was performed of women undergoing cervical surveillance following either history- or ultrasound-indicated cervical cerclage. We compared women managed with cervical cerclage and vaginal progesterone to women managed with cervical cerclage alone. Women with a singleton pregnancy who underwent cervical cerclage were identified from a database. Data on the concurrent use of vaginal progesterone, cervical length measurements, interventions and birth outcomes were collected from patient notes and clinical pathology notes. Patients from each intervention group were matched, based on exact shortest cervical length measurements obtained during surveillance and age of gestation when the measurement was obtained.

Results 66 women were matched and included in the study, based on exact shortest cervical length measurements. Each group had an identical mean shortest cervical length of 12.09 mm. The outcomes of 33 women who received both cervical cerclage and vaginal progesterone were compared to the outcomes of 33 women who were treated with cervical cerclage alone. The administration of vaginal progesterone to women with ongoing cervical shortening despite cervical cerclage was found to significantly prolong the pregnancy (36.36 weeks vs. 32.63 weeks; p = 0.0036) compared to women treated with cerclage alone. This use of rescue adjuvant vaginal progesterone was also associated with higher birth weights (2829 g vs. 2134 g; p = 0.0065) compared to women who had cervical cerclage alone; however, there was no difference in Apgar scores, composite neonatal morbidity or neonatal intensive care admission.

Conclusion Women with cervical shortening despite the presence of cervical cerclage may benefit from further TVUS cervical length surveillance and the administration of vaginal progesterone if further cervical shortening occurs. Despite both groups having clinically significant shortened cervical lengths and cervical cerclage in situ, adjunct vaginal progesterone treatment resulted in older gestational age at birth and higher birth weight. Further investigation and confirmation of this finding in a larger prospective trial is warranted to explore this potential benefit for the management of preterm birth in future.
Foetal Morbidity Depending on the Day and Time of Delivery
Authors: von Ehr Julia , Wiebking Nina , Kundu Sudip , von Kaisenberg Constantin , Hillemanns Peter , Soergel Philipp
Published: August 2018

Introduction It is known that perinatal mortality is increased with births at night and at the weekend. The aim of the study was to investigate whether there is also an association between the time of delivery (weekday, night, weekend) and perinatal morbidity.

Material and Methods All births at Hannover Medical College between 2000 and 2014 were included in a retrospective data analysis. Multiple births, primary sections, severe foetal malformations and intrauterine deaths were not included. A 5-minute Apgar score ≤ 5 and cord arterial pH < 7.10 were defined as perinatal morbidity. Besides the time of delivery, different variables that are regarded as risk factors for increased perinatal morbidity were studied. Univariate logistical regression analysis was performed, followed by multivariate analysis.

Results 18 394 deliveries were included in the study. Pathological prepartum Doppler, medical induction of labour and delivery at night and/or at the weekend significantly increased the probability of an Apgar score ≤ 5 after 5 minutes. The probability that a child will have cord arterial pH < 7.1 post partum is significantly increased with a BMI > 25 before pregnancy, primiparity, medical induction of labour, peripartum administration of oxytocic agents, when the delivery took place at night and weekend combined, but also when the delivery took place at night or at the weekend/on a public holiday. Multivariate regression analysis showed that a time of delivery at night and/or at the weekend or on a public holiday is not a prognostic factor for a 5-minute Apgar score ≤ 5 (p = 0.2377) but is a prognostic factor for cord arterial pH < 7.1 (p = 0.0252).

Conclusion The time of delivery at night or at the weekend/on a public holiday increases the risk for cord arterial pH < 7.1 by ~ 30% compared with delivery on a weekday. However, the time of delivery at night or at the weekend/on a public holiday does not increase the risk for the baby of having a 5-minute Apgar score ≤ 5.
Neoadjuvant Therapy of Cervical Carcinoma with the Angiogenesis Inhibitor Bevacizumab: a Single-Centre Analysis
Authors: Junker Philip , Puppe Julian , Thangarajah Fabinshy , Domröse Christian , Cepic Angela , Morgenstern Bernd , Ratiu Dominik , Hellmich Martin , Mallmann Peter , Wirtz Marina
Published: August 2018

Introduction Cervical cancer is the fourth most frequent cancer in women worldwide. Addition of the VEGF antibody bevacizumab in combination with platinum-containing chemotherapy achieved an improvement in overall survival in advanced cervical cancer. To date there are no data on neoadjuvant use of bevacizumab. We therefore studied the benefit of neoadjuvant combined therapy with bevacizumab in a group of cervical cancer patients.

Patients and Methods This retrospective cohort study analysed 14 patients with cervical cancer FIGO stages 1b1 to IV who received neoadjuvant platinum-containing chemotherapy in combination with bevacizumab. The comparative cohort consisted of 16 patients who were treated with neoadjuvant platinum-containing chemotherapy alone. The response rates were determined by means of preoperative clinical examination, diagnostic imaging (RECIST), changes in tumour markers (SCC) and by histopathology.

Results A clinical response was found in 93.8% (n = 15) of patients after bevacizumab-free therapy and in 100% (n = 14) of the patients who were treated with bevacizumab in addition. Combined therapy with bevacizumab led to a higher rate of clinical complete remission (42.9 vs. 12.5%; p = 0.072) and significantly improved the reduction in tumour size (Δ longest diameter: 3.7 vs. 2.5 cm; p = 0.025). Downgrading was observed in 100% of all patients treated with bevacizumab compared with 75% in the control arm. The rate of pathological complete remission (pCR) was not altered significantly (28.6% [n = 4] vs. 37.5% [n = 6]; p = 0.460).

Discussion Overall, combined therapy with bevacizumab led to a better clinical response. Operability was therefore improved more often. Because of the small patient cohort, larger prospective studies are necessary to validate the effect of neoadjuvant combined therapy with bevacizumab.
Communication in The Clinical Routine of Neonatologists
Authors: Börner Nele , Mache Stefanie , Scutaru Cristian , Metze Boris , Bührer Christoph
Published: August 2018

Introduction Communication is essential to clinical routine, especially in NICUs with their vulnerable patients and the special team caring for them. Communication breakdowns and resulting treatment errors are described in the literature. The aim of this study is to provide an initial quantitative assessment of medical communication in a NICU.

Methods For task analysis, 15 Level III-NICU physicians were accompanied for 60 days in early and late shifts; each physician completed the COPSOQ questionnaire. Recorded tasks were assigned to main task categories and subcategories.

Results A total of 550 h of main and 100 h of secondary tasks were recorded, on average 9 h daily. The most time-consuming main activity was “Communication” (3 h), followed by “Indirect care/Administration” (2 h) and “Direct patient care” (1.5 h). “Communication” mainly consisted of discussions with colleagues and during early shifts. At 2 min, communication with nursing personnel during rounds was especially low. Communication showed a negative correlation to physician job satisfaction.

Discussion This work shows the suspected high proportion of communication in a NICU, especially among physicians themselves. The effectiveness of this communication is not assessable. However, a low proportion of communication with nursing staff is noticeable and reflects the variabiliy in team communication. Improvement of communication is necessary through training on and the application of existing techniques for handoffs and rounds.
Between Access and Privacy: Challenges in Sharing Health Data
Authors: Malin Bradley , Goodman Kenneth ,   Section Editors for the IMIA Yearbook Special Section
Published: August 2018

Objective: To summarize notable research contributions published in 2017 on data sharing and privacy issues in medical informatics.

Methods: An extensive search of PubMed/Medline, Web of Science, ACM Digital Library, IEEE Xplore, and AAAI Digital Library was conducted to uncover the scientific contributions published in 2017 that addressed issues of biomedical data sharing, with a focus on data access and privacy. The selection process was based on three steps: (i) a selection of candidate best papers, (ii) the review of the candidate best papers by a team of international experts with respect to six predefined criteria, and (iii) the selection of the best papers by the editorial board of the Yearbook.

Results: Five best papers were selected. They cover the lifecycle of biomedical data collection, use, and sharing. The papers introduce 1) consenting strategies for emerging environments, 2) software for searching and retrieving datasets in organizationally distributed environments, 3) approaches to measure the privacy risks of sharing new data increasingly utilized in research and the clinical setting (e.g., genomic), 4) new cryptographic techniques for querying clinical data for cohort discovery, and 5) novel game theoretic strategies for publishing summary information about genome-phenome studies that balance the utility of the data with potential privacy risks to the participants of such studies.

Conclusion: The papers illustrated that there is no one-size-fitsall solution to privacy while working with biomedical data. At the same time, the papers show that there are opportunities for leveraging newly emerging technologies to enable data use while minimizing privacy risks.
Contributions from the 2017 Literature on Clinical Decision Support
Authors: Koutkias V. , Bouaud J. ,   Section Editors for the IMIA Yearbook Section on Decision Support
Published: August 2018

Objectives: To summarize recent research and select the best papers published in 2017 in the field of computerized clinical decision support for the Decision Support section of the International Medical Informatics Association (IMIA) yearbook.

Methods: A literature review was performed by searching two bibliographic databases for papers referring to clinical decision support systems (CDSSs). The aim was to identify a list of candidate best papers from the retrieved bibliographic records, which were then peer-reviewed by external reviewers. A consensus meeting of the IMIA editorial team finally selected the best papers on the basis of all reviews and the section editors' evaluation.

Results: Among the 1,194 retrieved papers, the entire review process resulted in the selection of four best papers. The first paper studies the impact of recency and of longitudinal extent of electronic health record (EHR) datasets used to train a data-driven predictive model of inpatient admission orders. The second paper presents a decision support tool for surgical team selection, relying on the history of surgical team members and the specific characteristics of the patient. The third paper compares three commercial drug-drug interaction knowledge bases, particularly against a reference list of highly-significant known interactions. The fourth paper focuses on supporting the diagnosis of postoperative delirium using an adaptation of the “anchor and learn” framework, which was applied in unstructured texts contained in EHRs.

Conclusions: The conducted review illustrated also this year that research in the field of CDSS is very active. Of note is the increase in publications concerning data-driven CDSSs, as revealed by the review process and also reflected by the four papers that have been selected. This trend is in line with the current attention that “Big Data” and data-driven artificial intelligence have gained in the domain of health and CDSSs in particular.
STRUCTURAL AND FUNCTIONAL CHARACTERIZATION OF DOMAINS IN THE HEAVY CHAIN REGION OF FACTOR XI (XIa) INVOLVED IN BINDING HIGH MOLECULAR WEIGHT KININOGEN AND FACTOR IX
Authors: Baglia F A , Sinha D , Walsh P N
Published: August 2018

Previous studies from our laboratory (J. Biol. Chem. 260:10714,1985; J. Clin. Invest. 78:1631,1986) provide evidence that a monoclonal antibody (3C1) directed against the heavy chain region of factor XIa (FXIa) recognizes an epitope near a substrate binding site for FIX and a binding site for high molecular weight kininogen (HMWK). The present studies were carried out to determine whether these two sites are identical or different. Another heavy-chain-specific murine monoclonal antibody (5F7) was found to recognize an epitope distinct from that recognized by 3C1 since 3C1 did not compete with 5F7 for binding to FXI in a solid-phase radioimmunoassay. Antibody 3C1 was a competitive inhibitor of F-XIa-catalyzed F-IX activation, assayed by the release of a 3H-labeled activation peptide from FIX, whereas 5F7 had no effect on F—IX activation by FXIa. In contrast, 5F7 (which also inhibited F-XIIa-catalyzed F-XI activation in the presence of HMWK and kaolin) completely blocked FXI binding to immobilized HMWK at concentrations 1,000-fold lower than 3C1. Finally, HMWK had no effect on F-IX activation by FXIa. We therefore conclude that two separate and distinct domains are present in the heavy-chain region of FXI, one of which is a substrate binding site for FIX and the other a binding site for HMWK. A 15,000 Mr peptide containing the HMWK binding site was isolated using cyanogen bromide digests of factor XI which were bound to and eluted from a ,5F7 antibody affinity column and further purified using high performance liquid chromatography. Gas phase sequencing studies are in progress to characterize this peptide and place its sequence within the known structure of the heavy chain of FXIa. In conclusion, our antibodies have defined two domains within the heavy chain region of FXI: one defined by 5F7 is near the HMWK binding site, whereas the other, recognized by 3C1, is a substrate binding site for FIX. Finally, a peptide domain in the heavy chain of FXI that compriaes the HMWK binding site has been identified and isolated.
ACTIVATION OF HUMAN ENDOTHELIAL TYPE PLASMINOGEN ACTIVATOR INHIBITOR (PAI-1) BY NEGATIVELY CHARGED PHOSPHOLIPIDS
Authors: Lambers J W J , Cammenga M , Konig B , Pannekoek H , van Mourik J A
Published: August 2018

The endothelial cell type plasminogen activator inhibitor (PAI-1) may exist in an active, latent form that can be converted into an active form upon exposure to denaturants such as sodium dodecyl sulphate (SDS), guanidine-HCl or urea. Here we show that latent PAI-1 can be activated with lipid vesicles, consisting of the negatively charged phospholipids phosphatidylserine (PS) or phosphatidylinositol (PI). The presence of a net negative charge on the phospholipid headgroup is essential for activation. Incubation with lipid vesicles, consisting of the zwitterionic phospholipids phosphatidylcholine (PC) and phosphatidylethanol-amine (PE), does not result in activation of the inhibitor. In the presence of PS vesicles, the capacity of PAI-1 to inhibit tissue type plasminogen activator (t-PA) is 50-fold higher than that of the untreated protein. For comparison, the activity of PAI-1 was enhanced 25-fold by treatment of the protein with SDS. PS induces activation of the inhibitor at much lower concentrations than SDS. For example, to achieve 50% inhibition of t-PA with a more than 100-fold excess of PAI-1, 0.25 nmoles of PS are required, whereas L.60 nmoles of SDS are necessary to reach half maximal inactivation of t-PA. Activation of PAI-1 by PS can be reversed by the addition of Ca2+-ions, suggesting that Ca2+-ions interfere with the interaction of PAI-1 with the negatively charged lipid surface, thus preventing its activation. The lipid-induced activation of PAI-1 points to a possibly important role of phospholipids in fibrinolysis; regulation of the fibrinolytic activity in blood plasma may ultimately be determined by the extent to which these phospholipids activate the inhibitor of t-PA.

This study was supported by the Netherlands Thrombosis Foundation.
THE LOCALIZATION OF PLATELET GpIIb-IIIa RELATED PROTEINS IN ENDOTHELIAL CELL ADHESION STRUCTURE
Authors: Dejana E , Languino L R , Colella S , Plow E , Ginsberg M , Marchisio P C
Published: August 2018

Different laboratories bave reported that human endothelial cells (EC) synthesize and express surface proteins biochemically and immunologically related to platelet GpIIb-IIIa. However the functional role of this glycoprotein complex in EC has not yet been elucidated. In this study we investigated whether these molecules are involved in the process of EC adhesion to different substrata. Cultured human umbilical vein ECs ,seeded on purified fibrinogen(fg), or vitronectin(VN) coated coverslips, adhered ,underwent spreading, organization of thick microfilament bundles and formation of focal contacts as shown by immunofluorescence and interference reflection microscopy.Polyclonal antibodies raised against human platelet GpIIb-IIIa and cross reacting with the EC form, showed by immunofluorescence a discrete and well organized distribution at cell adhesion structures, Indeed they distributed at vinculin rich focal contacts at the membrane insertion of microfilament bundles of stress fiber type.They were also found at cell to cell contacts and in a diffuse pattern at the dorsal surface of EC.GpIIb-IIIa antibodies added to EC suspensions prior to plating inhibited EC adhesion and spreading in a concentration dependent way. This effect was present at different degrees when EC were seeded on fg or VN being clearly more evident on VN and somehow less apparent on fg.In addition when the antibodies were added to confluent EC monolayers for 24 h they disrupted cell to cell contacts and caused cell rounding and detachment Preimmune serum or control antibodies able to bind to EC external membrane but which did not recognized GpIIb-IIIa proteins were unable to inhibit EC attachment and spreading. These results indicate that EC GpIIb-IIIa complex is involved in the adhesion mechanism of these cells to extracellular matrix proteins.
PLATELET AND ENDOTHELIAL CELL CYTOADHESINS ARE BIOSYNTHESIZED AND PROCESSED VIA SIMILAR PATHWAYS
Authors: Polack B , Duperray A , Berthier R
Published: August 2018

The cytoadhesin family represents a group of heterodimeric adhesion receptors with common structural, fonctional and immunochemical properties. Platelet and endothelial cell (EC) GPIIbIII a related proteins exemplify two members of this family. In the present study the biosynthesis and processing of EC GPIIbIII a were examined and compared with that of platelet GPIIbIIIa to verify whether the diversity of these cytoadhesins was related to post translational events.

Endothelial cells of human umbilical cord vein origin were metabolicaly labeled with 35S-methionine. The newly synthesized proteins were analyzed and immunoprecipitated with polyclonal antibodies against the purified platelet GPIIbllla complex and the isolated GPIIb and GPIIIa. Under non-reducing conditions three bands were detected at 135 kD, 125 kD and 90kD with the anti GPIIbIIIa. Samples obtained from pulse chase experiments and analysed under non reducing conditions indicated that the 135 kD band derived from the 125 kD band. Under reducing conditions the 135 kD generated two bands at 118 kD and 25 kD. The 125 KD band also gave a 118 kD band and the 90 kD band shifted to 100 kD. These results indicated that the mature form of 135 kD is composed of two polypeptidic chains which derive from a common single chain precursor similar to that observed in the megakaryocyte. The mature protein and the precursor molecule were not recognised by anti GPIIb antibodies. Also immunoprecipitated by polyclonal anti GPIIIa antibodies was a single chain protein of 100kD. In addition, endoglycosidase treatement showed that both EC GPIIIa and platelet GPIIIa were glycosylated protein of the high mannose type.

These results indicate that although structural differences exists between platelet and endothelial cell GPIIbllla, the two membrane glycoproteins have a similar cellular transit.
MONTREAL PLATELET SYNDROME: DECREASED ACTIVITY OF PLATELET CALPAINS ASSOCIATED WITH AGGREGATION ABNORMALITIES
Authors: Okita J R , Frojmovic M M , Kristopeit S , Wong T , Kunicki T J
Published: August 2018

The Montreal platelet syndrome (MPS) is an inherited disorder of platelet function characterized by a) severe thrombocytopenia, b) formation of "giant" platelets upon physical or biochemical stimulation, c) spontaneous aggregation (stir-induced microaggregate formation) and d) a lack of aggregation in response to thrombin. The Bernard-Soulier syndrome (BSS) is similar to MPS in that both syndromes are characterized by "giant" platelets and an abnormal aggregation response to thrombin. BSS patients have a deficiency of specific platelet glycoproteins (GPs). From our investigations we conclude MPS patients have apparently normal amounts of major platelet GPs. However, a defect in calpains (calcium-activated neutral proteinases) was detected in MPS platelets. The specific activity of calpains was decreased by 70% (p<0.001) in the cytosolic fraction of platelets from MPS patients as compared to that of platelets from normal control donors. The calpain activity of platelets from BSS patients was within the normal range.

During the course of the biochemical studies, platelets from the MPS patients were shown to exhibit concurrent functional defects, i.e., stir-induced spontaneous aggregation and reduced to absent aggregation response to thrombin. It is concluded that MPS can be distinguished from BSS at the molecular level as follows: 1) MPS platelets contain normal amounts of GPs Ib, V and IX which are decreased or absent in BSS platelets; 2) The specific activity of calpains is reduced in MPS platelets but normal in BSS platelets. Supported by NIH (HL-33925, HL-32279), Amer. Heart Assoc. (85—GA—67, 83-186), Canadian Med. Res. Council (248-59) and Quebec Heart Fndn.
STUDIES ON ROLE OF CALPAIN IN PLATELET REACTION, UTILIZING NEWLY SYNTHETIZED PEPTIDE ANTAGONISTS
Authors: Kajiwara Y , Sakon M , Tsujinaka T , Kambayashi J , Mori T , Murachi T
Published: August 2018

The system of calpain (Ca2+-activated protease) and its inhibitor calpastatin in platelets have been well characterized in our laboratory but the role of the system has not been fully elucidated yet, though various endogenous substrates have been identified. Employing SH inhibitors as calpain antagonists, We have proposed a possible role of platelet calpain in myosin light chain (20K) phosphorylation (Biochem.Int. 6,767,1986) but more specific calpain antagonists were required to draw conclusion. Recentry, series of peptide calpain antagonists(PCAs) were syn-thetized such as Ac-Leu-Leu-Nle.al(PCA-I), Ac-Leu-Leu-Met.al(PCA-II) and Leu-Leu-Phe.CH2Cl(PCA-III)(J.Biochem.99,173,1986) and attempts were made to apply them to platelet reaction. ID50 of PCAs against platelet calpain I was as follows; PCA-I:0.04uM,PCA-II:0.luM and PCA-III:0.4uM. Thus, these antagonists were 1000 times more potent than N-ethylmaleimide(NEM), and they did not inhibit Mg2+-ATPase activity of platelet myosin B in contrast to NEM. When PCAs were applied to intact platelets, no effect was obtained against stimulus-linked proteolysis of ABP(aotin binding protein) and P235, indicating poor permeability of the antagonists across the plasma membrane. Thereby PCA was applied to lysed platelets or to permeabilized platelets. Lysed platelets suspension with 2mM EGTA, 2mM EDTA was incubated at 37 C with 32P -ATP,2mM MgCl2, 3mM CaCl2 in the presence or absence of PCA-II and proteolysis of. ABP,P235 and phosphorylation of 20K,47K were studied. The proteolysis and phosphorylation were inhibited by PCA-II in a dose-related manner. Then, PCA-II was applied to permeabilized platelet prepared by a high voltage electric charge to which acriflavine was loaded. PCA-II inhibited Ca2+ stimulated proteolysis and phosphsrylation of the permeabilized platelets likewise but no effect was obtained on Ca2+ stimulated acriflavine secretion from dense granules. These observations indicated that the proteolysis and protein phosphorylation are mediated by calpain but that these phenomena may not be related to secretory process.
A COMPARISON OF THE BINDING OF ANTITHROMBIN III AND HEPARIN COFACTOR II TO HEPARINS, NATURALLY OCCURRING GLYCOSAMINOGLYCANS AND OTHER SULPHATED POLYMERS
Authors: Dawes J , Pepper D S
Published: August 2018

Antithrombin III (ATIII) and heparin cofactor II (HCII) are currently thought to be the most important protein mediators of the anticoagulant and antithrombotic activities of glycosamino-glycans. A simple, quantitative method for assessing the affinity of a protein for a sulphated polymer in the liquid phase, based on competition with immobilised heparin, has been developed. Using this technique, the binding of ATIII and HCII to a wide range of glycosaminoglycans and other sulphated polymers have been compared, and the contributions to binding of size, degree of sulphation and backbone structure of the polymers analysed.

In the presence of the high protein concentrations found in plasma, unfractionated heparin inhibited the binding of ATIII to immobilised heparin with a Ki of 1 x 10-6. Binding was destroyed by N-desulphation. 1 Results with a range of low molecular weight (LMW) heparins and heparan sulphates are consistent with the view that they all contain the ATIII-binding sequence, but at a lower molar ratio than heparin. Highly sulphated synthetic polymers such as dextran sulphate bound ATIII by a different mechanism, which was molecular weight-dependent.

The affinity of HCII for heparins increased markedly with heparin chain length. Binding was largely, but not entirely, mediated by sulphate residues. HCII bound to heparan and dermatan sulphates with lower affinities than to heparin, and to synthetic sulphated polymers with similar or higher affinities. Pentosan polysulphate (SP54) bound HCII as effectively as did heparin. Binding of HCII to dextran sulphate was highly dependent on molecular weight. The affinity of HCII for a sulphated polymer appears to depend both on its chain length and density of sulphation.

Thus the profiles of binding of ATIII and HCII to glycosaminoglycans and other sulphated polymers are quite different. This technique is useful both for investigating the interactions of existing therapeutic anticoagulants and assessing new products.
MOLECULAR CONFORMATION OF THE PENTASACCHARIDE CORRESPONDING TO THE BINDING SITE OF HEPARIN TO ANTITHROMBIN III
Authors: Choay J , Petitou M , Perly B , Casu B , Ragazzi M , Ferro D
Published: August 2018

The knowledge of the tridimensional structure of the sequence required in heparin for binding to anti thrombin III (AT) is essential for the understanding of the molecular basis of the anticoagulant and antithrombotic activity of this glycosamino-glycan. This problem was approached by a combined experimental (chemical synthesis and Nuclear Magnetic Resonance, "NMR") and theoretical (force field calculations) study of the pentasaccharide I reproducing the minimal sequence for high affinity binding to AT.

NMR data (interproton coupling constants and nuclear-Over-hauser-enhancement) were used to test a number of possible conformation of I proposed on the basis of-molecular energy calculation. In particular, these studies, confirming the results obtained by force field calculations, showed that the sulfated iduronic residue (Is) conformation is an equilibrium between the chair 4C4 and the skew boat2S0, and permitted to discard models with the Is residue in the alternate chair 4C1. It is of interest that the relative population of the 4C4 and 2S0 conformers of IS in sequence I (40:60) is reversed with respect to that found for the same residue in the regular sequences of heparin (60:40), such a reversal being largely associated with electrostatic interactions caused by the unique 3-0-sulfo group ot the preceding amino sugar residue. The most favoured models of I are characterized by a cluster of anionic groups including all the sulfate groups proposed as essential for full expression of the activity (full line square on the formula) but one (dotted line square on the formula), plus the carboxylate group of the glucuronic acid residue.
MOLECULAR CLONING OF THE HUMAN GENE FOR VON WILLEBRAND FACTOR AND IDENTIFICATION OF THE TRANSCRIPTION INITIATION SITE
Authors: Collins Corolyn J , Levene Richard B , Ravera Christina P , Dombalagian Marker J , Livingston David M , Lynch Dennis C
Published: August 2018

Most patients with von Willebrand's disease appear to have a defect affecting the level of expression of the von Willebrand factor (vWf) gene. Thus, an understanding of the pathogenesis of von Willebrand's disease will require an analysis of the structure and function of the vWf gene in normals and in patients. To begin such analyses, we have screened a human genomic cosmid library with probes obtained from vWf cDNA and isolated a colinear segment spanning ≈175 kb in five overlapping clones. This segment extends ≈25 kb upstream and ≈5 kb downstream of the transcription start and stop sites for vWf mRNA, implying the vWf gene has a length of ≈150 kb. Within one of these clones, the vWf transcription initiation sites have been mapped. A portion of the promoter region has been sequenced, revealing a typical TATA box, a downstream CCAAT box, and a perfect downstream repeat of the 8 base pairs containing the major transcription start site. Primer extension analysis suggests that sequences contained within the downstream repeat of the transcription start site may be used as minor initiation sites in endothelial cells. Transfection studies are underway to evaluate the role of sequences within this promoter region in gene regulatory activity. Comparative restriction analyses of cloned and chromosomal DNA segments strongly suggests that no major alterations ocurred during cloning and that there is only one complete copy of the vWf gene in the human haploid genome. Similar analyses of DNA from vWf-expressing endothelial cells and non-expressing white blood cells suggests that no major rearrangements are associated with vWf gene expression. Finally, cross hybridization patterns among seven mammalian species suggests a strong conservation of genomic sequences encoding the plasma portion of vWf, but a lower degree of conservation of sequences encoding the N terminal region of provWf.
VON WILLEBRAND FACTOR (vWF) PRO-POLYPEPTIDE IS REQUIRED FOR vWF MULTIMER FORMATION
Authors: Verweij C L , Hart M , Pannekoek H
Published: August 2018

The von Willebrand factor (vWF) is a multimeric plasma glycoprotein synthesized in vascular endothelial cells as a pre-pro-polypeptide with a highly repetitive domain structure, symbolized by the formula:

(H)-D1-D2-D'-D3-A1-A2-A3-D4-B1-B2-B3-C1-C2-(0H).

A heterologous expression system, consisting of a monkey kidney cell line (C0S-1), transfected with full-length vWF cDNA, is shown to mimic the constitutively, secretory pathway of vWF in endothelial cells. The assembly of pro-vWF into multimers and the proteolytic processing of these structures is found to oro-ceed along the following, consecutive steps. Pro-vWF subunits associate to form dimers, a process that does not involve the pro-polypeptide of pro-vWF. This observation is derived from transfection of C0S-1 cells with vWF cDNA, lacking the genetic information encoding the pro-polypeptide, composed of the domains D1 and D2. Pro-vWF dimers are linked intracellularly to form a regular series of multimeric structures that are secreted and cannot be distinguished from those released constitutively by endothelial cells. The presence of the pro-polypeptide, embedded in pro-vWF, is obligatory for multimerization since the deletion mutant lacking the D1 and D2 domains fails to assemble beyond the dimer stage. It is argued that the D domains are involved in interchain interactions.
DIVERGENT PATES OF VON WILLEBRAND FACTOR AND ITS PROPOLYPEPTIDE (VON WILLEBRAND ANTIGEN II) AFTER SECRETION FROM ENDOTHELIAL CELLS
Authors: Wagner D D , Fay P J , Sporn L A , Sinha S , Lawrence S O , Marder V J
Published: August 2018

The intracellular site of cleavage of pro-von Willebrand factor subunit and the subsequent fate of the propolypeptide (von Willebrand antigen II) and of the mature von Willebrand factor (vWf) were investigated. Both the propolypeptide, which was found to be a homodimer of non-covalently linked subunits, and mature vWf were released from Weibel-Palade bodies of endothelial cells following stimulation with secretagogues. The stoichiometry of the two proteins in the releasate was essentially equimolar. This indicates that vWf and the propolypeptide were packaged into the Weibel-Palade bodies as one unit, pro-vWf, and that the proteolytic cleavage of pro-vWf is likely to be a post-Golgi event. The association of prosequences into dimers provides support for their hypothetical role in the multimerization process. After secretion, the two proteins were distributed differently, as based on the following observations. The propolypeptide did not associate with vWf in the culture medium, did not co-distribute with vWf in the extracellular "patches of release" on stimulated endothelial cells, and was not detected in the endothelial cell extracellular matrix, which did contain vWf. Additionally, in contrast to vWf, the propolypeptide did not bind to matrix of human foreskin fibroblasts. Since the propolypeptide does not associate with vWf and does not interact witji extracellular matrices in vitro, it is highly unlikely that it would promote platelet adhesion to subendothelium in vivo.
PREVENTION OF OCCLUSIVE CORONARY THROMBOSIS BY MONOCLONAL ANTIBCDY TO VON WILLEBRAND FACTOR IN SWINE
Authors: Nichols T C , Bellinger D A , Read M S , Reddick R L , Brinkhous K M , Griggs T R , Lamb M A
Published: August 2018

Von Willebrand's disease protects pigs from developing cyclic or permanent coronary thrombosis (C/P-Th) following experimentally induced stenosis and injury (S/I) in an open chest anesthetized pig (Nichols et al, Circ Res., 1986; 59:1526). To confirm that this protection is related specifically to absence of von Willebrand factor (vWF), an IgG kappa monoclonal antibody (MAb) to purified porcine vWF was produced in mice. MAb inhibited platelet aggregation by ristocetin and botrocetin, but not ADP, thrombin, or collagen. MAb was infused into seven normal pigs. Bleeding times (BT) in all pigs were prolonged to >10 min, and platelet agglutinating factor levels as a measure of vWF activity were <2% for approximately 2 hours or longer. There was no significant change of hematocrit, platelet count or Factor VIII coagulant activity. Coronary stenosis was produced by placing a Goldblatt clanp (GC) around the left anterior descending coronary artery (LAD). A 20-MHz Doppler velocity crystal was placed distal to GC to measure LAD blood flow velocity. The LAD was injured at the GC site with spring loaded forceps. C/P-Th were detected by flow velocity changes and vessels were examined by light and scanning electron microscopy. Five of seven pigs were given MAb prior to S/I; after S/I, four of these five had no C/P-Th. The fifth pig developed C/P-Th after 2 hours when vWF activity had returned to 10% and BT had shortened to 2.5 min. The other two pigs were given MAb after S/I had produced C/P-Th. The first had total resolution and the second partial resolution of these cyclic thromboses. This S/I technique produced C/P-Th in 8 of 9 normal pigs. Thus, this MAb reduces vWF activity and prevents C/P-Th. This study confirms a direct role of vWF in supporting occlusive coronary thrombosis in this porcine model and suggests reduction of vWF activity could be a therapeutic approach to arterial thrombotic diseases. (Supported by Grant Nos. HL26309-06 and HL01648-40. MAb supplied by Bruce Evatt, M.D., C.D.C., Atlanta, Georgia)