1,720,955 research outputs found
Sedation of Patients with Acute Aneurysmal Subarachnoid Hemorrhage with Ketamine Is Safe and Might Influence the Occurrence of Cerebral Infarctions Associated with Delayed Cerebral Ischemia
No full textBACKGROUND: Ketamine has neuroprotective characteristics as well as beneficial cardiocirculatory properties and may thus reduce vasopressor consumption. In contrast, sedation with ketamine (like any other sedative drug) has side effects. This study assesses the influence of ketamine on intracranial pressure (ICP), on the consumption of vasopressors in induced hypertension therapy, and on the occurrence of delayed cerebral ischemia (DCI)-associated cerebral infarctions, with particular focus on the complications of sedation in patients with aneurysmal subarachnoid hemorrhage (SAH). METHODS: This is a retrospective, observational study. Sixty-five patients with SAH who underwent a period of sedation were included. The clinical course variables (Richmond Agitation and Sedation scale score, ICP values, consumption of vasopressors, complications of sedation, outcome, and other clinical parameters) were analyzed. Cranial computed tomography results were analyzed. RESULTS: Forty-one patients underwent sedation including ketamine (63.1%). Ketamine decreased the ICP in 92.7% of the cases. Vasopressors was reduced in 53.6%. DCI-associated cerebral infarctions occurred significantly less often in the patient cohort being treated with sedation including ketamine (7.3% vs. 25% in the nonketamine group; P = 0.04). The rate of major complications was not higher in the ketamine group. Outcome was not different regarding the groups if they were sedated with or without ketamine. CONCLUSIONS: Ketamine decreases the ICP and is not associated with a higher rate of complications. The rate of DCI-associated cerebral infarctions was lower in the ketamine group. Ketamine administration led to a reduction of vasopressors used for induced hypertension
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
Characterization of the microglia in glioblastoma and their interaction with tumor blood vessels
No full textGlioblastoma multiforme (GBM) ist ein primärer bösartiger Hirntumor bei
Erwachsenen. Das Tumorparenchym enthält verschiedene Zelltypen, darunter ein
Drittel Mikroglia/Makrophagen. In den Untersuchungen haben wir uns mit der
Interaktion von Mikroglia/Makrophagen mit Blutgefäßen befasst und die
Lokalisierung von Mikroglia/Makrophagen in bestimmten Bereichen des Tumors
angeschaut, um ihre mögliche Rolle in der Tumorvaskularisation zu definieren.
Wir verwendeten ein syngenes Tumor – Mausmodell vom Glioblastoma multiforme.
Dabei wurden GL261 – Tumorzellen in die Gehirne von C57/BL6-Mäusen
implantiert. Dann wurden die Gehirnschnitte bezüglich der Interaktion der
Mikroglia/Makrophagen mit Endothelzellen und/oder Perizyten mit Hilfe von
Immunfluoreszenzfärbungen analysiert. Weiterhin wurden TUNEL – und Hif1α –
positive Zellen analysiert, um die apoptotische Aktivität von
Mikroglia/Makrophagen und ihr Verhalten in den hypoxischen Tumorarealen zu
beschreiben. Wir fanden, dass bis zu 30% der Blutgefäße von Tumoren mit zwei
oder mehr Mikroglia/Makrophagen assoziiert sind. Diese Iba1 – positive Zellen
befanden sich überwiegend in Kontakt mit Endothelzellen im Tumorbereich.
Außerdem stellten wir auch die Interaktion der Mikroglia/Makrophagen mit
Perizyten fest (ca. 20% im Tumorareal). Darüber hinaus zeigten
Mikroglia/Makrophagen im hypoxischen Tumorbereich teilweise die Expression von
Hif1α. Überraschenderweise zeigten die Analysen der TUNEL – Färbung nur wenige
apoptotische Zellen im Tumor an. Die meisten dieser apoptotischen Zellen waren
dabei Mikroglia/Makrophagen, die keine Hif1α – Expression zeigten. Desmin
zeigte sich als nur schwer zu verwendender Marker für die Perizytenanalyse, da
auch Desmin+ - Zellen detektiert wurden, die keinen Kontakt zu den
Endothelzellen der Tumorblutgefäße aufwiesen. Zudem waren diese Zellen zum
Teil auch Iba-1+. Dabei wurde die zelluläre Transformation von Perizyten in
Mikroglia/Makrophagen postuliert. Ferner wurden im Tumor Gliomzellen entdeckt,
welche das Protein mesenchymalen Ursprunges Desmin exprimierten. Darüber
hinaus erwiesen einige der Gliomzellen die mikroglialen Eigenschaften, wie
z.B. die Iba-1 – Expression, was die neue Hypothese der zellulären Fusion
zwischen Tumorzellen und Mikroglia/Makrophagen unterstützen würde. In
zukünftigen Studien könnte die detaillierte Untersuchung der
Mikroglia/Makrophagen – Gefäß – Interaktion zu einem besseren Verständnis der
Rolle der Mikroglia/Makrophagen in der Tumorangiogenese und damit auch für die
Progression des Glioms führen.Glioblastoma multiforme (GBM) is the most malignant primary brain tumor in
adults. The tumor compartment contains various cell types, with about one
third of microglia/macrophages. In our investigations, we analyzed the
interaction of microglia/macrophages with blood vessels and at the
localization of microglia/macrophages in specific areas of the tumor to define
their putative role for tumor vascularisation. We used a syngenic tumor mouse
model of glioblastoma multiforme. Therefore, we implanted GL261 tumor cells
into brains of C57/BL6 mice. Then, we evaluated brain sections for the
interaction of microglia/macrophages with endothelial cells and/or pericytes
by immunofluorescence stainings. Furthermore, we analyzed TUNEL and Hif1α
positive cells to clarify the apoptotic activity of microglia/macrophages and
their appearance in hypoxic areas of the tumor. We found that up to 30% of the
tumor blood vessels are associated with two or more microglia/macrophages.
These Iba1 positive cells are predominantly contacting endothelial cells but
in the intratumoral area we detected also interaction of microglia/macrophages
and pericytes (approx. 20%). In addition, microglia/macrophages in the hypoxic
tumor area partly showed expression of Hif1α. Most of the hypoxic
microglia/macrophages are located in the perivascular niche or around Hif1α
positive tumor cells. Surprisingly, the analyses of TUNEL staining showed only
a few apoptotic cells in the tumor area. And most of these apoptotic cells
were microglia/macrophages, which did not express Hif1α. Desmin proved to be a
difficult-to-use marker for analysis of pericytes, as well as desmin+ - cells
were detected which had no contact with the endothelial cells of tumor blood
vessels. In addition, these cells were also partly Iba-1+. The cellular
transformation of pericytes in microglia / macrophages has been postulated.
Furthermore, glioma cells were detected in the tumor expressing the protein of
mesenchymal origin desmin. Some of the glioma cells demonstrated the
microglial characteristics, such as the Iba-1 - expression, which would
support the new hypothesis of cellular fusion between tumor cells and
microglia / macrophages. In future studies, the detailed investigation of the
microglia/macrophages and vessel interaction could lead to a better
understanding of the role of microglia/macrophages on tumor angiogenesis
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
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