1,720,967 research outputs found
Rat schwann cells express M1-M4 muscarinic receptors subtypes
No full textThe expression of different muscarinic receptor subtypes was analyzed in immature Schwann cells obtained from sciatic nerve of 2-day neonatal rats. By using RT-PCR analysis, we demonstrated the presence of M1, M2, M3, and M4 receptor subtypes in cultured Schwann cells, with M2 displaying the highest expression levels. Muscarinic subtypes were also quantified by immunoprecipitation and [3H]QNB binding. With this approach, we found the levels of receptor expression to be M2 > M3 > M1. M4 is expressed at very low levels, and M5 receptor was not detectable. Moreover, we also demonstrated that stimulation of the receptors by muscarinic agonists activates previously described signal transduction pathways, leading to a decrease of cAMP and an increase of IP3 levels not associated with an efficient intracellular Ca2+ release. The presence and activity of particular muscarinic receptors in immature Schwann cells suggest that ACh may play an important role in Schwann cell development
Peripheral nerve ultrasound changes in CIDP and correlations with nerve conduction velocity
No full textTo evaluate the ultrasound (US) characteristics of peripheral nerves in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and their correlations with electrodiagnostic (EDX) characteristics.
METHODS:
Nineteen patients with CIDP and 19 healthy controls matched by age and body mass index were included in a blind case-control, observational study. All patients underwent a neurologic examination (including inflammatory neuropathy cause and treatment [INCAT] and Medical Research Council [MRC] sum score) and an EDX study. Each patient and each control underwent a US study of 14 nerve segments, yielding a total number of 266 segments scanned in each group.
RESULTS:
US changes, characterized by an increased nerve cross-sectional area (NCSA), were detected in 53% of the 266 patient nerve segments. Mean NCSA was higher in nerve segments of patients than in those of controls (p < 0.001). Nerve segments with abnormal US belonged to patients with longer disease duration, lower MRC sum score, higher INCAT score, and progressive disease form (all p < 0.0001). All the aforementioned variables were independently associated with the occurrence of US changes. Motor nerve conduction was significantly lower in nerve segments with increased NCSA than in those with normal NCSA (p < 0.0001). NCSA in segments with prevalent myelin damage was higher than that in segments with prevalent axonal damage (p = 0.001) or in segments with normal EDX characteristics (p < 0.0001). NCSA and motor nerve conduction velocity were inversely correlated in nerve segments with EDX evidence of myelin damage (R = 0.599; p < 0.0001). Conduction blocks were associated with increased NCSA (p = 0.001).
CONCLUSIONS:
US may, similar to MRI, have a supporting role in the diagnosis of CIDP. US and EDX changes are correlated
Widening the phenotypical spectrum of EGR2-related CMT: unusual phenotype for R409W mutation
No full textThe Authors report a 46-year-old man who had presented, since his late thirties, a slowly progressive symmetric distal limb weakness and atrophy, associated with mild distal sensory loss. A heterozygous c.1225C > T (R409W) mutation on EGR2 gene was detecte
Acetylcholine inhibits cell cycle progression in rat Schwann cells by activation of the M2 receptor subtype
No full textCultures of schwalla cells froill ncoaatal rat sciatic aenes ivere treated with acety1cholilic agonists tvid the cjj cts oil cell Prolificratiou cniluatcd. 3[HI-thyaiidiac incorporation shows that accty1choliac (ACh) receptor agoiiists ilillibit cell proliftratioti, aiid FACS analysis deinoustratcs ccll-cyclc arrest and accunlulatioii of cells ill the Gi phase. The use of arecaiditie, a selective agouist of niuscariiiic M2 receptors reveals that this effect depends nictitily oil jW2 receptor acth,atioii. The arecaidine i1cpetialci i t- block ill Gi is rci,ersible becausc reinoval of arecaidiue froai the culture iiieditaii mduccs progrcssioil to the S phase. The block of the Gj-S transitioil is also characterized by inodulatiou of the expressioti ofscwrol cell-cycic inarkcrs. Morcoi,cr, trcatnicat ivith ACh receptor agmist causes both a decreasc ill the PCNA prolcin lci,cls ill Schivaiiii cell iniclci aad all iiicreasc ill P27 Olld P53 proteins. Filially, iinnnuio-elcctrou inicroscopy dcalonStl-atCS that M2 receptors arc expressed by Schivanii cells ill i,ivo. These results inclicate that ACh, by aiodulatiiig Schwaiin cell prolificratioii through M2 I-CCCPtOl- aclivatioa,)iiight cowributc to their progression to a niore dif rewiated phenotype
SCHWANN CELL TRANSITION FROM PROLIFERATING TO MATURE PHENOTYPE, COUNTERACTING NRG1 ACTION
No full text
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
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