1,721,197 research outputs found
Investigation of adult corneal limbal neurosphere cells: a potential autologous cell resource for retinal repair
No full textThe potential of limbal neurosphere cells to differentiate into retinal cell phenotypes
No full textPurpose: Neural colonies (neurospheres) can be generated from adult corneal limbus in vitro. We previously showed that neurospheres derived from limbus were of neural crest origin and can differentiate into functional neurons in vitro. The aim of this study was to investigate whether limbal neurosphere cells (LNS) could differentiate into retinal like cells in vitro and in vivo when exposed to a retinal developing microenvironment.Methods: Cells from adult (8-week old) murine corneal limbus were isolated and cultured in a serum-free sphere-forming system in the presence of mitogens. Following co-culture with developing retinal cells in vitro, LNS and their progeny were characterized using immunocytochemistry, reverse transcription-polymerase chain reaction (RT-PCR) and transmission electron microscopy (TEM). Enhanced Green Fluorescent Protein (eGFP) labelled limbal neurosphere cells were transplanted into the subretinal space (SRS) of neonatal mice. The potential for limbal cells to differentiate into retinal like cells and integrate into the host retina was assessed by immunohistochemistry after 2-5 weeks.Results: LNS cells formed a monolayer, with cells displaying neuronal morphologies following co-culture with neonatal retinal cells. Expression of retinal progenitor cell markers Pax6, Lhx2 and Six6 were observed by RT-PCR after 2-4 days of co-culture. Following 7-10 days in co-culture, LNS cells were immunopositive for the photoreceptor specific marker rhodopsin (13 ± 3%), the mature neuronal marker neurofilament 200 (31 ± 10%) and a major component of synapses within the retina Syntaxin3 (9± 2%)). LNS also displayed ultrastructural changes following differentiation. TEM revealed loss of junctions within the LNS and the presence of putative presynaptic dense bodies. In addition, non-motile primary cilia were also detected in differentiated LNS cells. Although not specific to retinal lineage cells, the same subtype of sensory cilia is present in photoreceptor and RPE cells. Following transplantation into the SRS of wildtype neonatal mice, rhodopsin was detected in eGFP labelled LNS cells.Conclusions: These data highlight that corneal limbal stromal stem/ progenitor cells can transdifferentiate to a retinal like phenotype in vitro and in vio. Therefore LNS cells could be a potential resource for autologous cell rescue of degenerative retinal diseases
Characterisation of mouse limbal neurosphere cells: a potential cell source of functional neurons
No full textBACKGROUND/AIMS:To characterise the origin, ultrastructure and functional properties of corneal limbal neurospheres (LNS).METHODS:Limbal cells were isolated from the corneal limbus of adult mice and cultured in a serum-free sphere forming culture system. LNS were characterised by immunocytochemistry, Reverse-transcription-PCR and electron microscopy. LNS cells were also cocultured with neonatal mouse retinal cells. Phenotype and function were then assessed by immunofluorescence and a calcium influx/efflux assay.RESULTS:LNS cells displayed clonal growth and self-renewal, and expressed a wide range of stem cell and neural lineage markers. The acquisition of neural properties was concordant with expression of neural crest markers including CD34, Sca1, Sox9, Twist1, but not CD45. LNS exhibited similar morphology and microstructure to neurospheres derived from the central nervous system. Following culture in a conducive environment, the derived cells displayed mature neural markers and exhibited electrical excitability.CONCLUSIONS:Corneal limbal stromal progenitor cells are a potential and convenient autologous cell source to generate functional neurons
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
- …
