1,720,956 research outputs found
Stage and quantify regenerative myogenesis in FES-induced functional recovery of human long-term permanent denervated muscle
No full textAbstract
Following denervation, skeletal muscle undergoes rapid loss in both mass and contractile
force, with an accompanying series of changes in structure, biochemistry and physiology.
Morphologic features of the long-term denervated muscle suggest that the original fibers are
lost and those seen are the results of repeated cycles of cell death and regeneration. Markers
of myogenic events in adult muscles are activated satellite cells, presence of embryonic my-
osin and myogenic transcription factors. Electrical stimulation of permanent denervated mus-
cle increases the mean size of the myofibers, maintains the sarcomeres and possibly prevents
apoptosis/necrosis and secondary degeneration.
We here describe histological, immunohistochemical and molecular methods, which identify
markers of damage, regeneration, and repair on a muscle sample of just a few milligrams. A
suitable source is a small biopsy, whose cryostat sections allow fiber typing and histopathol-
ogy by immunochemical analyses. A few additional serial cryostat sections are used for mo-
lecular analyses. By light morphometry percent fat and/or interstitial tissue area, and fiber size
distribution are determined. Myosin ATPases and immunohistochemistry are used to quantify
fiber types, including early or late regenerated myofibers. By electron microscopy we identify
abnormalities of sarcomeric organization, nuclear distribution, mitochondrial content, and ac-
tivated satellite cells. Myosin heavy chain profiles are indicators of regenerative events and of
muscle adaptation to changing demands. Total protein content, myosin: total protein and my-
osin: actin ratios are determined by SDS-PAGE to reliably complement or substitute mor-
phometry in quantifying muscle trophism in skeletal muscle biopsies.
Taken together the results of morphometry and molecular analyses solidly demonstrate that
two-year-long FES substantially reverses the severe atrophy expected in four-year dener-
vated human muscles, and that generative/regenerative myogenic events significantly con-
tribute to the functional recovery of long-term paralyzed human muscles.
Key words: atrophy, FESS, long-term permanent denervation, morphometry, regeneration,
SDS-PAGE, skeletal muscle, therapeutic functional electrical stimulation.
Basic Appl Myol 12 (6): 277-286, 200
Apoptosis in mouse skeletal muscles after physical exercise.
No full textApoptosis in mouse skeletal muscles after physical exercise.
Podhorska-Okołów M, Krajewska B, Carraro U, Zabel M.
Folia Histochem Cytobiol. 1999;37(2):127-8. No abstract available.
PMID:
10352991
[PubMed - indexed for MEDLINE
Functional in vivo gene transfer into the myofibers of adult skeletal muscle
No full textBiochem Biophys Res Commun. 2003 Dec 26;312(4):1132-8.
Functional in vivo gene transfer into the myofibers of adult skeletal muscle.
Donà M, Sandri M, Rossini K, Dell'Aica I, Podhorska-Okolow M, Carraro U.
Source
Department of Biomedical Sciences, C.N.R. Institute of Neuroscience, Unit for Neuromuscular Biology and Physiopathology, University of Padova, Viale G. Colombo 3, I-35121, Padova, Italy.
Abstract
The postmitotic nature and longevity of skeletal muscle fibers permit stable expression of any transfected gene. Direct in vivo injection of plasmid DNA, in both adult and regenerating muscles, is a safe, inexpensive, and easy approach. Here we present an optimized electroporation protocol based on the use of spatula electrodes to transfer cDNA in vivo into the adult myofibers of an anatomically defined muscle, which could be functionally characterized. In our hands, about 80% of adult myofibers were transfected in vivo by different plasmids for GFP fusion proteins or for beta-galactosidase. The luciferase activity increased several orders of magnitude when compared to standard DNA delivery. In an anatomical defined muscle, the wide gene transfer was comparable to or better than that of retrovirus delivery, that recently has been shown to be prone to severe side-effects in human clinical studies. Furthermore, with our method the tissue damage was greatly decreased. Thus, the present work describes in vivo functional electrotransfer of genes in adult skeletal muscle fibers by a protocol that is of great potential for gene therapy, as well as for basic research.
PMID:
14651990
[PubMed - indexed for MEDLINE
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
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