1,720,955 research outputs found
Impaired remyelination in late-onset multiple sclerosis
No full textAbstract A reduced regenerative capacity may contribute to faster disease progression and poorer relapse recovery in multiple sclerosis patients with disease onset after the age of 50, a condition known as late-onset multiple sclerosis (LOMS). We hypothesized that lesions in LOMS patients show more pronounced axonal damage, less remyelination and an altered inflammatory composition, and performed a detailed histopathological analysis of MS biopsies in patients with early-stage LOMS. The number of T cells, B cells, plasma cells, microglia/macrophages, different oligodendrocyte populations as well as the axonal density and acute axonal damage were assessed in 31 LOMS and 30 normal-onset MS (NOMS, 20–40 years old) patients. No major differences in the inflammatory infiltrate or axonal damage were found. BCAS1-positive oligodendrocytes indicating early myelinating oligodendrocytes, and mature oligodendrocytes were significantly lower in the normal-appearing white matter of LOMS compared to NOMS patients ( p = 0.05; p = 0.01), with a negative correlation with age (r = − 0.5, p = 0.01). In active demyelinating lesions, the number of BCAS1-positive oligodendrocytes did not differ between LOMS and NOMS, but NOMS lesions showed a higher proportion of ramified cells indicating active remyelination. In LOMS, BCAS1-positive oligodendrocytes decreased with increasing lesion age, with the lowest numbers found in inactive demyelinated lesions. In contrast, NOMS patients showed high numbers of BCAS1-positive cells with an activated morphology, even in inactive demyelinated lesions. At the last follow-up, LOMS patients had a significantly higher EDSS score (median 3.5) than NOMS patients (median 3.0, p = 0.05). A higher EDSS score correlated with fewer mature and oligodendrocyte precursor cells in active demyelinating lesions (r = − 0.4, p = 0.01 and r = − 0.6, p = 0.003). These findings suggest a clinically relevant impaired oligodendrocyte differentiation and remyelination in LOMS. Since remyelination is essential for axonal protection, it will be necessary to consider the complex and dynamic tissue environment when researching therapeutics aimed at fostering the differentiation of oligodendrocyte precursor cells into myelinating oligodendrocytes.Sanofi-Aventis Deutschland https://doi.org/10.13039/100019944Herzzentrum Göttinge
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
Dimethyl fumarate impairs differentiated B cells and fosters central nervous system integrity in treatment of multiple sclerosis
No full textn multiple sclerosis (MS), the effect of dimethyl fumarate (DMF) treatment is primarily attributed to its capacity to dampen pathogenic T cells. Here, we tested whether DMF also modulates B cells, which are newly recognized key players in MS, and to which extent DMF restricts ongoing loss of oligodendrocytes and axons in the central nervous system (CNS). Therefore, blood samples and brain tissue from DMF-treated MS patients were analyzed by flow cytometry or histopathological examination, respectively. Complementary mechanistic studies were conducted in inflammatory as well as non-inflammatory CNS demyelinating mouse models. In this study, DMF reduced the frequency of antigen-experienced and memory B cells and rendered remaining B cells less prone to activation and production of pro-inflammatory cytokines. Dissecting the functional consequences of these alterations, we found that DMF ameliorated a B cell-accentuated experimental autoimmune encephalomyelitis model by diminishing the capacity of B cells to act as antigen-presenting cells for T cells. In a non-inflammatory model of toxic demyelination, DMF limited oligodendrocyte apoptosis, promoted maturation of oligodendrocyte precursors and reduced axonal damage. In a CNS biopsy of a DMF-treated MS patient, we equivalently observed higher numbers of mature oligodendrocytes as well as a reduced extent of axonal damage when compared to a cohort of treatment-naïve patients. In conclusion, we showed that besides suppressing T cells, DMF dampens pathogenic B cell functions, which probably contributes to its clinical effectiveness in relapsing MS. DMF treatment may furthermore limit chronically ongoing CNS tissue damage, which may reduce long-term disability in MS apart from its relapse-reducing capacity
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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