1,721,016 research outputs found
Granular Media Calcinosis in the Aortic Walls of Patients With Bicuspid and Tricuspid Aortic Valves
No full textBackground. Bicuspid aortic valve (BAV), the most frequent congenital cardiac abnormality, is associated with a higher risk for ascending aortic aneurysms and aorta-related complications (ie, dissection and rupture). The aim of this study was to quantify granular media calcinosis (GMC) in the ascending aortic wall of patients with BAV. Methods. We analyzed samples of the ascending aorta from patients with BAV (n = 54) and patients with tricuspid aortic valve (TAV) (n = 33) who underwent aortic repair, regarding medial thickness and diameter expansion. Additionally, the convexity and concavity of the samples were stained for GMC and elastin fragmentation. Results. The quantitative analysis revealed a significantly higher extent of GMC in patients with BAV at the aortic convexity and concavity compared with patients with TAV, independent of aortic diameter. Additionally, GMC increased with enlargement of the aortic diameter in patients with BAV. Furthermore, we found a significantly reduced total medial thickness in patients with BAV compared with patients with TAV. Conclusions. Our findings highlight GMC as a prominent feature of bicuspid aortopathy. (C) 2017 by The Society of Thoracic Surgeon
Surgical management of the aorta in BAV patients
No full textPatients with a bicuspid aortic valve (BAV) frequently develop aneurysms of the aortic root and tubular ascending aorta. Aneurysms of the aortic arch, in the absence of concomitant aortopathies, are much less common. According to the 2018 American Association of Thoracic Surgery consensus guidelines on BAV-related aortopathy, prophylactic surgical aortic repair / replacement is recommended starting at a maximum aortic diameter of 50 mm in patients with risk factors. Concomitant aortic surgery is also recommended at an aortic diameter of 45 mm in those patients with other indications for cardiac surgery (most commonly aortic valve procedures). The ultimate goal of prophylactic aortic surgery is the prevention of aortic catastrophes, e.g. aortic rupture or acute aortic dissection, which are associated with high morbidity and mortality. The surgical technique used - in elective and emergency cases depends on the involvement and nature of the aortic valve disease, as well as the extent of aortic aneurysm formation. The current review focusses on the surgical management of the aortic root, tubular ascending aorta, and proximal aortic arch in BAV patients. Despite the abovementioned recommendations, many BAV patients develop acute aortic syndromes below the recommended aortic diameter thresholds. Further research is therefore required in order to identify high-risk BAV subgroups that would benefit from earlier surgical repair. (c) 2020 Elsevier Inc. All rights reserved
Contemporary spinal cord protection during thoracic and thoracoabdominal aortic surgery and endovascular aortic repair: a position paper of the vascular domain of the European Association for Cardio-Thoracic Surgery†.
Full text linkIschaemic spinal cord injury (SCI) remains the Achilles heel of open and endovascular descending thoracic and thoracoabdominal repair. Neurological outcomes have improved coincidentially with the introduction of neuroprotective measures. However, SCI (paraplegia and paraparesis) remains the most devastating complication. The aim of this position paper is to provide physicians with broad information regarding spinal cord blood supply, to share strategies for shortening intraprocedural spinal cord ischaemia and to increase spinal cord tolerance to transitory ischaemia through detection of ischaemia and augmentation of spinal cord blood perfusion. This study is meant to support physicians caring for patients in need of any kind of thoracic or thoracoabdominal aortic repair in decision-making algorithms in order to understand, prevent or reverse ischaemic SCI. Information has been extracted from focused publications available in the PubMed database, which are cohort studies, experimental research reports, case reports, reviews, short series and meta-analyses. Individual chapters of this position paper were assigned and after delivery harmonized by Christian D. Etz, Ernst Weigang and Martin Czerny. Consequently, further writing assignments were distributed within the group and delivered in August 2014. The final version was submitted to the EJCTS for review in September 2014
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Untersuchung von AGE und RAGE im proximalen Aortenaneurysma von Patienten mit bikuspider oder trikuspider Aortenklappe
Full text linkIn der vorliegenden Arbeit wurde aneurysmatisches Aortengewebe von Patienten mit
bikuspider oder trikuspider Aortenklappe untersucht. Im Laufe des Lebens ist die
bikuspide Aortenklappe als häufigste angeborene Anomalie des Herzens mit
zahlreichen, potentiell lebensbedrohlichen Komplikationen verbunden. Betroffene
Patienten zeigen eine frühere Entwicklung und rapidere Progression von Dilatationen
und – im schlimmsten Fall – Dissektionen der Aorta ascendens. Die Ätiologie dessen
konnte bis dato nicht ausreichend geklärt werden. Hintergrund der Studie war eine
Untersuchung von Branchetti et al., wobei eine Erhöhung von RAGE im Plasma bei
Patienten mit bikuspider Klappe nachgewiesen werden konnte. Daraus wurde die
Hypothese entwickelt, dass eine Expressionserhöhung von RAGE und dessen
Liganden AGE im Aortengewebe selbst ursächlich mit der Aortendilatation verbunden
sein könnte. In Proben von 93 Patienten wurde mittels Western Blot, ELISA und
Immunhistochemie die Expression von RAGE und AGE untersucht. Hierbei zeigte sich
eine signifikante Expressionserhöhung beider Proteine im Aortenaneurysma bei
bikuspider Klappe im Vergleich zu Patienten mit trikuspider Aortenklappe. Auch die
exemplarisch angefertigten Immunhistologien stützen diese Ergebnisse. Mögliche
Folgen können Steifigkeitserhöhung der Aortenwand, Aktivierung von
Matrixmetalloproteinasen sowie Erhöhung des oxidativen Stresses sein.
Neben der Expression im aneurysmatischen Aortengewebe wurden auch
Plasmaproben hinsichtlich AGE und RAGE analysiert, wobei sich keine Erhöhung
feststellen ließ. Die Ergebnisse der Studie, die eine RAGE – Erhöhung im Plasma
detektierten und ihn somit als potentiellen Biomarker für eine bikuspide Klappe
diskutierten, ließen sich bei der vorliegenden Untersuchung einer kleineren Stichprobe
nicht bestätigen. Ebenso stellt sich die Etablierung eines Biomarkers als
anspruchsvolle Aufgabe dar. Eine Eignung von RAGE als Biomarker zur Identifikation
von Patienten mit bikuspider Klappe ist kritisch zu betrachten.:Inhaltsverzeichnis
Bibliographische Beschreibung
Abkürzungsverzeichnis
1. Einleitung
1.1. Die bikuspide Aortenklappe (BAV)
1.1.1. Prävalenz
1.1.2. Klassifikation
1.1.3. Ätiologie
1.1.4. Assoziierte Pathologien
1.1.5. Hypothesen der Dilatationsentstehung
1.1.6. Diagnostik
1.1.7. Therapie
1.2. RAGE und AGE
1.2.1. Advanced Glycation End Products (AGE)
1.2.2. Receptor for Advanced Glycation End Products (RAGE)
1.2.3. Interaktion von AGE und RAGE
1.2.4. Bezug zum thorakalen Aortenaneurysma
2. Zielstellung
3. Material
3.1. Allgemeine Geräte
3.2. Allgemeine Materialien
3.3. Allgemeine Chemikalien
3.4. Proteinextraktion
3.5. Proteinkonzentrationsbestimmung
3.6. SDS – Gelelektrophorese
3.7. Antikörper (AK)
3.8. Western Blot Analyse
3.9. Enzyme – linked Immunosorbent Assay (ELISA)
3.10. Immunhistochemie (IHC)
3.11. Software
4. Methoden
4.1. Patientenpopulation und Probengewinnung
4.2. Isolation der Proteine aus Aortengewebe
4.3. Konzentrationsbestimmung nach BCA – Methode
4.4 Elektrophoretische Auftrennung der Proteine
4.5. Detektion von AGE und RAGE mittels Western Blot Analyse
4.6. Nachweis von AGE und RAGE mittels ELISA
4.7. Immunhistochemische Färbung von AGE und RAGE
4.8. Statistische Auswertung
5. Ergebnisse
5.1. Patientenpopulation
5.2. Expression von AGE in humanen aneurysmatischen Gewebeproben der Aorta ascendens
5.2.1. Analyse der AGE – Expression mittels Western Blot
5.2.2. Analyse der AGE – Expression mittels ELISA
5.2.3. Darstellung der Lokalisation von AGE in der Aortenwand mittels Immunhistochemie
5.3. Expression von RAGE im Aortengewebe
5.3.1. Analyse der Expression von RAGE mittels Western Blot
5.3.2. Analyse der RAGE – Expression mittels ELISA
5.3.3. Darstellung der Lokalisation von RAGE in der Aortenwand mittels Immunhistochemie
5.4. Bestimmung der Plasmaspiegel von AGE und RAGE in ausgewählten Plasmaproben
6. Diskussion
6.1. Expressionserhöhung von AGE in der Aortenwand von Patienten mit BAV
6.1.1. Mögliche Ursachen der Expressionserhöhung
6.1.2. Zusammenhang von AGE und Gefäßsteifigkeit
6.2. Expressionserhöhung von RAGE im Aortengewebe von Patienten mit BAV
6.2.1. Ätiologie der Expressionserhöhung unter Einbeziehung der Liganden
6.2.2. Folgen der RAGE – Erhöhung und ihr Einfluss auf die Gefäßwand
6.3. RAGE in seiner Rolle als Biomarker
Schlussfolgerung
Limitationen
7. Zusammenfassung
8. Literaturverzeichnis
9. Abbildungsverzeichnis
10. Tabellenverzeichnis
Erklärung über die eigenständige Abfassung der Arbeit
Lebenslauf
Danksagun
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Aortic events and reoperations after elective arch surgery: incidence, surgical strategies and outcomes
No full textThe true incidence of aortic events (AEs) and reoperations (REDO) following elective total aortic arch replacement remains unknown. The aim of this study was to review the incidence of AEs and surgical REDO, and its respective outcomes after 1232 elective arch repairs at 11 European aortic centres
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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