1,720,957 research outputs found
Cell and Tissue Microarray Technologies for Protein and Nucleic Acid Expression Profiling
No full textTissue microarray (TMA) and cell microarray (CMA) are two powerful techniques that allow for the immunophenotypical characterization of hundreds of samples simultaneously. In particular, the CMA approach is particularly useful for immunophenotyping new stem cell lines (e.g., cardiac, neural, mesenchymal) using conventional markers, as well as for testing the specificity and the efficacy of newly developed antibodies. We propose the use of a tissue arrayer not only to perform protein expression profiling by immunohistochemistry but also to carry out molecular genetics studies. In fact, starting with several tissues or cell lines, it is possible to obtain the complete signature of each sample, describing the protein, mRNA and microRNA expression, and DNA mutations, or eventually to analyze the epigenetic processes that control protein regulation. Here we show the results obtained using the Galileo CK4500 TMA platform
iPS cells : quality controls and validation to become a cell product
No full textHuman embryonic stem cells (hESCs) provide new resources for the biomedical community by virtue of their dual capacities: long-term self-renewal and production of differentiated progeny. hESCs may constitute an endless source of cells for the treatment of debilitating diseases and degenerative disorders. In the last few years alternatives to hESCs have been generated, the ”induced pluripotent stem cells” (iPS) which can repro-gram their adult somatic fate to acquire an embryonic-like feature thanks to the ectopic over-expression of four transcription factors (OCT-4, SOX-2, KL44 and c-MYC). iPS cells nowadays represent the biggest expectation for the emerging molecular stem cell medicine branch, although they are not as versatile as the hESCs, but much still needs to be learned of their characteristics and capacities. These cells retain their own genome and an imprint or un-erasable memory of their somatic cellular origin and whatever has occurred in the organ from which they originate. It is then of paramount importance to invest on “methyloma” or methylation profiles of these cells in order to identify their memory stick.
Since the number of iPS lines will steadily increase, to become an accreditable cell product, they must be submitted to a number of quality control tests to assure that they are morphologically and biochemically undistinguishable from ESCs. Particularly it is essential to analyze the reactivation of the appropriate stage-specific embryonic antigens, the capacity to differentiate into lineages from all three embryonic germ layers, the teratomas formation in immunodeficient mice, the expression of functional telomerase, the epigenetic status and the transcriptionally permissive chromatin structure of pluripotent genes. iPS should be evaluated by integrative genome-wide approaches, allowing the supervising of pluripotency, or the eventual DNA damage subsequent to the reprogramming
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
SEL1L in pancreas development and ß-cell function
No full textThe study of genes governing pancreas development could help the advancement of cell-replacement therapies for diabetes. SEL1L, a component of the endoplasmic reticulum associated degradation (ERAD) pathway, has been reported to regulate: (i) the differentiation of the pancreatic endocrine and exocrine tissue during the secondary transition of mouse embryonic development (Li et al., Dev Bio 2010), (ii) the neural stem cell self-renewal and lineage commitment (Cardano et al., JBC 2011), and (iii) cell cycle progression through regulation of genes related to cell-matrix interaction (Cattaneo et al., Neoplasia 2005).
Here, we show that SEL1L expression is developmentally regulated, such that it is expressed in developing islet cells and in nascent acinar clusters adjacent to basement membranes, whereas in the adult pancreas it becomes restricted to the islets of Langherans. This expression pattern, together with the identification of two inverse RGD motifs in the fibronectin type II domain of SEL1L, led us to investigate its possible interaction with cell adhesion molecules to regulate islets architecture. Co-immunoprecipitation studies revealed an interaction between SEL1L and ß1-integrin, while down-modulation of SEL1L in pancreatic ß-cells negatively influences cell adhesion on selected matrix components.
Furthermore, the absence of SEL1L protein strongly inhibits glucose-stimulated insulin secretion in isolated mouse pancreatic islets unveiling an important role of SEL1L in insulin trafficking.
These results provide preliminary insights into the cross-talk between extracellular matrix and insulin signalling in creating a favourable micro-environment for ß-cell development and function
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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