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Morphologische und histopathologische Untersuchung der sympathischen Innervation der Arteriae renales und Arteriae carotides
Full text linkHintergrund: Die Reduktion eines erhöhten Blutdrucks kann das Risiko für kardiovaskuläre Komplikationen, wie Herzinsuffizienz, Myokardinfarkt, Schlaganfall und Sterblichkeit senken. Trotzdem erreichen bis zu 40% der Patienten mit arterieller Hypertonie nicht die empfohlenen Zielblutdrucke. Da für die Blutdruckregulation unter anderem das sympathische Nervensystem und die arteriellen Barorezeptoren im Bereich des Karotissinus eine zentrale Rolle spielen, werden zur Behandlung der Hypertonie interventionelle Therapien untersucht, die die renalen sympathischen Nervenfasern veröden oder den Barorezeptorreflex modulieren. Für die Entwicklung von Kathetersystemen und zur Verbesserung der Prozedur sind Kenntnisse über die Verteilung vegetativer Nervenfasern entlang der Arteriae (Aa.) renales und Aa. carotides essenziell. Das Ziel der vorliegenden Arbeit ist es, die Dichte und den Verlauf von vegetativen Nerven entlang der Aa. renales und Aa. carotides zu untersuchen. Methoden: Die Aa. renales von zehn und die Aa. carotides von neun Körperspendern wurden im anatomischen Institut der Universität des Saarlandes entnommen. Nach der Thorakotomie und Präparation des Herzens und der Lungen, wurden die Aorta und die abdominellen Organe en-bloc entnommen. Die Aa. renales und abdominelle Gefäße wurden nach Feinpräparation und Markierung abgesetzt. Die Aa. carotides wurden durch einen lateralen Zugang entlang des M. Sternocleidomastoideus präpariert, markiert und an ihrem Austritt aus dem Thorax, sowie auf der Höhe des Eintritts in die Schädelbasis abgesetzt. Die Präparate wurden verarbeitet und mit histologischen Färbungen (Hämatoxylin & Eosin, S100, Tyrosinhydroxylase, Calcitonin gene-related peptide) gefärbt. Die Lokalisation der Nerven entlang der Arterien und das Vorliegen relevanter Strukturen wurde dokumentiert. Weiterhin wurde die Lumen-Nerv-Distanz, der Durchmesser der Nerven und der efferente und afferente Anteil der Nerven bestimmt.
Ergebnisse: Insgesamt wurden 6781 Nerven entlang 18 Aa. renales (zwei Patienten mit unilateraler Nephrektomie in der Vorgeschichte) und 3496 Nerven entlang 17 (bei drei Arterien durch starke Beschädigungen keine Analyse möglich) Aa. carotides analysiert.
Die mittlere Lumen-Nerv-Distanz der Nervenfasern entlang der linken und rechten Aa. renales betrug 2,32±1,95 mm und 2,29±2,03 mm (p=0,161). Die Lumen-Nerv-Distanz nahm von ostial nach distal ab. Im proximalen Segment lag sie bei 3,7±2,3 mm, im mittleren Segment bei 2,5±2,0 mm, im distalen Segment proximal der Bifurkation der Arterien bei 1,9±1,6 mm und distal der Bifurkation bei 1,3±1,0 mm (p140 μm) registriert. Die Tyrosinhydroxlase-positiv-gefärbte Fläche (efferente Anteile) überwog deutlich der Calcitonin gene-related peptide-positiv- gefärbte Fläche (afferente Anteile). Insgesamt lagen diese bei 95,5±5,9 % und 4,5±5,9 %.
Entlang der Aa. carotides war die Lumen-Nerv-Distanz in den Prä-Bulbus-, Bulbus- und Post- Bulbus-Segmenten der Aa. carotides: 2,85±1,4 mm, 2,91±1,38 mm bzw. 2,45±1,48 mm (p<0,001). Die Zahl der Nerven pro Quadranten unterschied sich nicht signifikant zwischen dem Prä-Bulbus- (7,1±7,3 Nerven pro Quadranten), Bulbus- (7,8±7,0 Nerven pro Quadranten) und Post-Bulbus- (7,6±8,7 Nerven pro Quadranten) Segment (p=0,567). Im Gefäßsegment Prä-Bulbus besaß die Nervengröße „groß“ den höchsten Anteil (38,8 %). In allen anderen Segmenten hatten „kleine“ Nerven den größten Anteil. Dieser zeigte sich im arteriellen Verlauf weiter steigend. Die Tyrosinhydroxylase-positiv-gefärbte (efferente) Fläche der Nerven machte den größten Anteil der positiv gefärbten Fläche aus (90,5±11,1 %). Die Calcitonin gene-related peptide-positiv-gefärbte (afferente) Fläche lag bei 9,5±11,1 % der insgesamt positiv gefärbten Fläche.
Schlussfolgerung: Die Lumen-Nerv-Distanz der Nerven im perivaskulären Bereich der Aa. renales nahm von proximal nach distal ab. Nerven in den distalen Bereichen waren überwiegend kleiner, efferent und näher am Lumen gelegen. Basierend auf diesen Erkenntnissen könnte die Behandlung von distalen Gefäßabschnitten mittels renaler Denervation eine effektivere Ablation sympathischer Nervenfasern ermöglichen.
Die Verteilung der Nerven entlang der Aa. carotides unterschied sich von der der Aa. carotides. Eine sinkende Lumen-Nerv-Distanz mit sinkender Nervengröße im arteriellen Verlauf war ebenfalls vorhanden, jedoch scheint dies zu den Aa. renales geringer ausgeprägt zu sein. Das Überwiegen von efferenten Anteilen der Nerven war hier ebenfalls gegeben, jedoch in geringerem Ausmaß als bei den Aa. renales. Studien zur Nervendistribution in diesem Bereich sind rar, womöglich könnten durch weitere Erkenntnisse Therapieverfahren verbessert werden.
Im Rahmen dieser Arbeit wurde ein Vorgehen zur präzisen Entnahme von Gefäßen entwickelt, eine Methodik erarbeitet mit der Nervenverteilungen um verschiedene Gefäße untersucht werden können und Erkenntnisse gewonnen, die wichtige Informationen zum Innervationsmuster der Nieren- und hirnversorgenden Gefäße liefern.Background: Treatment of arterial hypertension can reduce the risk of cardiovascular morbidity and mortality, including myocardial infarction, heart failure and stroke. The kidney, the sympathetic nervous system, and arterial baroreceptors, particularly along the carotid arteries, play crucial roles in blood pressure regulation. Therefore, interventional procedures, such as renal denervation, carotid body ablation, and baroreceptor stimulation are investigated for treating hypertension. Knowledge of the distribution of nerves along the renal and carotid arteries is essential for developing catheter systems and optimizing procedures. Herein, we aimed to assess the distribution of nerves along the renal and carotid arteries.
Methods: The renal arteries of ten and the carotid arteries of nine body donors were explanted and analyzed at the anatomical institute of Saarland University, Homburg (Saar).
After thoracotomy and removal of lungs and heart, the aorta and abdominal organs were explanted en bloc. The renal and abdominal vessels were removed after fine dissection and marking. The carotid arteries were prepared via a lateral approach along the sternocleidomastoid muscle, marked, and cut at their exit from the thorax, as well as proximal to their entry into the skull base. The tissue was processed and stained (haematoxylin and eosin, S100, tyrosine hydroxylase, calcitonin gene-related peptide). Digital analysis was used to measure lumen-nerve distance and nerve diameter and register surrounding anatomical structures. The ratio of efferent and afferent nerves was calculated by dividing the area of tyrosine hydroxylase and calcitonin gene-related peptide staining of the same nerves in the same section.
Results: A total of 6,781 nerves surrounding 18 renal arteries (two patients with a history of unilateral nephrectomy) and 3,496 nerves surrounding 17 (in three arteries no analysis because of damage) carotid arteries were analyzed. The average lumen-nerve distance of the left renal artery (2.32±1.95 mm) was slightly larger compared to the right renal artery (2.29±2.03 mm; p=0.161). These distances varied in different segments of the arteries: 3.7±2.3 in the proximal, 2.5±2.0 in the middle, 1.9±1.6 in the distal pre-bifurcation, and 1.3±1.0 mm in the distal post-bifurcation segments (p140 μm) were found. The tyrosine hydroxlase-positive-stained area (efferent) outweighed the calcitonin gene-related peptide-positive-stained area (afferent). Overall, these were 95.5±5.9% and 4.5±5.9%, respectively.
The mean distances in the pre-bulbar (n=792), bulbar (n=408) and post-bulbar (n=1714) segments of the carotid artery were: 2.85±1.4 mm, 2.91±1.38 mm and 2.45±1.48 mm (p<0.001). The number of nerves per quadrant was not significantly different between the pre- bulbus (7.1±7.3 nerves per quadrant), bulbus (7.8±7.0 nerves per quadrant) and post-bulbus (7.6±8.7 nerves per quadrant) segments (p=0.567). In the pre-bulbus vascular segment, the nerve size large possessed the highest proportion (38.8%). In all other segments, small nerves had the largest proportion. This was shown to increase further in the arterial course. Tyrosine hydroxylase-positive-stained (efferent) area of nerves accounted for the largest proportion of positively stained area (90.5±11.1%). Calcitonin gene-related peptide-positive-stained (afferent) area was 9.5±11.1% of the total positively stained area.
Conclusion: In the distal segments and along branches nerves converge to the lumen of the renal arteries. This results in the fewest number of nerves per quadrant and the shortest lumen- nerve distance in the distal post-bifurcation segments. Predominantly small and efferent nerves occur. Based on these findings, treatment of distal vessel segments by renal denervation may translate into more effective ablation of sympathetic nerve fibers.
The distribution of nerves along the carotid arteries differs from that of the renal arteries. The nerves also converge to the carotid arteries, with decreasing nerve size in arterial course, however, to a lesser extent than along renal arteries. Likewise, the predominance of efferent fibers is less pronounced than along renal arteries. Studies on nerve distribution and density may facilitate revision of technique and technology to renal denervation.
In the course of this work, a technique for precise sampling of vessels was developed, a methodology was worked out with which nerve distributions around different vessels can be analyzed, and findings were obtained that support existing knowledge but also provide new data on innervation patterns of the kidneys and brain
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
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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