1,720,975 research outputs found
Gut endocrine cell population in coeliac disease estimated by immunocytochemistry using a monoclonal antibody to chromogranin
No full textAbstract
Abnormalities of gut endocrine responses, as well as changes in the number of different endocrine cell types, have been reported convincingly in coeliac patients. Nevertheless, no estimation of total numbers of gut endocrine cells has yet been made in well defined groups of coeliacs. In this study, we have visualised all endocrine cell types in jejunal biopsies from coeliac patients with active and quiescent disease as well as in controls, using a monoclonal antibody to chromogranin. This protein was purified originally from bovine adrenal medulla and is known to be a reliable marker for all endocrine cells of the gut. The following groups were considered: (a) nine coeliacs with active illness, (b) 10 coeliacs under gluten-free diet, (c) eight coeliacs receiving gluten challenge, (d) five non-coeliacs (controls). Histological (haematoxylin and eosin) and immunocytochemical (peroxidase anti-peroxidase) stains were applied to 3 μm paraffin sections. Quantitative estimation of endocrine cell density was made using four different methods in order to evaluate the results fully (number of cells/mm2, number of cells/visual field, number of cells/8 crypts-villi, number of cells/unit of length of muscularis mucosae). In patient groups (a) and (c), coeliacs with active disease and coeliacs on gluten challenge diet respectively, a significantly higher number of endocrine cells was observed in comparison with normal controls (group d). In group (b) patients, coeliacs on gluten-free diet, no significant changes in the number of endocrine cells were observed in comparison with controls. Our results show that a significant increase in endocrine cell density exists ion coeliacs with active illness (group a and c), in comparison with controls. This condition is resolved in coeliacs receiving a gluten-free diet (group b)
Increased populations of endocrine cells in Crohn's ileitis
No full textAbstract
Hyperplasia of nerves has been described previously in Crohn's disease. To determine whether similar alteration of the enteric endocrine system occurs, endocrine cells of the ileal epithelium were quantified in typical cases of the disease. In the ileum from patients with Crohn's disease, there was an increase in the endocrine cell population, as visualised by immunostaining of chromogranin. Quantification of endocrine cell numbers showed significant increases in both macroscopically uninvolved (i.e. histologically normal) (35.0±3.8, cells per unit length of muscularis mucosae mean ±SEM, P<0.05) and involved (44.5±5.5, P<0.01) Crohn's disease samples, compared with normal controls (23.7±3.4). Although individual types of endocrine cell showed slight increases in Crohn's samples, only the enterochromaffin cells in abnormal bowel showed a significantly greater population (normal controls 10.5±2.3; involved Crohn's 21.3±4.4, P<0.05)
Neuron specific enolase: a common marker for the endocrine cells and innervation of the gut and pancreas.
No full textNeuron specific enolase, the most acidic isoenzyme of the glycolytic enzyme
enolase, was first believed to be present exclusively in central neurons. More
recently, it has been found in peripheral autonomic nerves and in a number of
endocrine cells. An immunocytochemical study was carried out concerning the
distribution of neuron specific enolase in the gastrointestinal tract and
pancreas of humans and rats. In addition, immunocytochemistry and histochemistry
were used to obtain a characterization of the different types of cells and nerves
in which neuron specific enolase can be detected. Neuron specific enolase was
found in all currently identifiable endocrine cell types and nerves of the gut
and pancreas. Neuron specific enolase is therefore a common marker for both
endocrine cells and enteric nerves, thus providing a simple means for their
simultaneous demonstration and examination of their morphologic characteristics
and integration
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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