1,720,957 research outputs found
Neuron-glia interactions and neuroinflammation: in vitro approaches to elucidate spinal cord disorders pathophysiology
Get PDFNeuroinflammation is a characterizing trait of various central nervous system (CNS) pathologies, from neurodegenerative diseases to neuropsychiatric disorders.
In the effort of dissecting the impact of immune status alterations on neural circuit function, we focused our study on the effects of local inflammation in a controlled micro-environment where neurons and neuroglial cells maintain their appropriate organization: the organotypic spinal cord slices. These cultures, developed from the spinal cord of mouse embryos, represent a complex in vitro model where sensory-motor cytoarchitecture, synaptic properties and spinal cord resident cells, encompassing heterogeneous neuronal phenotypes and neuroglia, are retained in a 3D fashion.
I have used this model to mainly investigate: 1) synaptic spinal changes induced by inflammation and mechanisms by which the inhibitory transmission is modulated; 2) resident microglia and astrocytes reactivity to inflammatory stress; 3) astrocytes calcium activity tuned by inflammation; 4) mechanisms which modulate calcium release and spreading in the inflamed tissues. Overall, my main aim was to understand the link between neuroinflammation and spinal pre-motor network. For the purpose, organotypic spinal cord slices are cultured for two weeks in vitro. Then, they are exposed for 4 and 6 hours to a cocktail of cytokines (CKs, 10 ng/mL), composed by tumor necrosis factor alpha (TNF alpha), interleukin-1 beta (IL-1 beta) and granulocyte macrophage-colony stimulating factor (GM-CSF), or to lipopolysaccharide (LPS, 1 μg/mL). I use single cell electrophysiology, live cell calcium imaging, immunocytochemistry, confocal microscopy and immunoblotting analysis to investigate and compare the spinal tissue responses to neuroinflammation induced by CKs and LPS. I first focus on the synaptic level, describing a progressive increase in the frequency of spontaneous post-synaptic currents (sPSCs) and inhibitory post-synaptic currents (IPSCs) and the shortening of GABAergic current due to CKs incubations, absent in LPS treated ones. I further explore by immunofluorescence and confocal microscopy, resident neuroglia reactivity, describing the activation of different inflammatory status, given by the two different paradigms, confirmed by the presence of cytokines and chemokines released in the supernatants. By live calcium imaging, I document an increase in the occurrence of calcium oscillations displayed by the astrocytes located in the ventral horn, and by several pharmacological treatments, I dissect the behavior of the oscillations, trying to understand their origin and mechanism of spreading.
In conclusion, my work compared the effects of a cytokines cocktail and of LPS in altering the pre-motor circuits signaling, that may contribute to sustain spinal network increased excitability, eventually leading to neurodegeneration
Cytokine inflammatory threat, but not LPS one, shortens GABAergic synaptic currents in the mouse spinal cord organotypic cultures
Get PDFBackground: Synaptic dysfunction, named synaptopathy, due to inflammatory status of the central nervous system (CNS) is a recognized factor potentially underlying both motor and cognitive dysfunctions in neurodegenerative diseases. To gain knowledge on the mechanistic interplay between local inflammation and synapse changes, we compared two diverse inflammatory paradigms, a cytokine cocktail (CKs; IL-1β, TNF-α, and GM-CSF) and LPS, and
their ability to tune GABAergic current duration in spinal cord cultured circuits.
Methods: We exploit spinal organotypic cultures, single-cell electrophysiology, immunocytochemistry, and confocal microscopy to explore synaptic currents and resident neuroglia reactivity upon CK or LPS incubation. Results: Local inflammation in slice cultures induced by CK or LPS stimulations boosts network activity; however, only CKs specifically reduced GABAergic current duration. We pharmacologically investigated the contribution of
GABAAR α-subunits and suggested that a switch of GABAAR α1-subunit might have induced faster GABAAR decay time, weakening the inhibitory transmission. Conclusions: Lower GABAergic current duration could contribute to providing an aberrant excitatory transmission
critical for pre-motor circuit tasks and represent a specific feature of a CK cocktail able to mimic an inflammatory reaction that spreads in the CNS. Our results describe a selective mechanism that could be triggered during specific inflammatory stress
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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