1,720,971 research outputs found
Substance P is diminished and vasoactive intestinal peptide is augmented in psoriatic lesions and these peptides exert disparate effects on the proliferation of cultured human keratinocytes
No full textAn involvement of neurogenic components in the pathogenesis of psoriatic lesions has been suggested and neuropeptides are thought to play a modulatory role in cutaneous inflammation. In this study, we evaluated the immunoreactivity of the neuropeptides vasoactive intestinal polypeptide (VIP) and substance P (SP) in the skin of patients with chronic plaque psoriasis, by immunohistochemistry and radioimmunoassay. No differences were observed, by immunohistochemistry, in the expression and localization of VIP and SP between psoriatic and normal skin. Using the radioimmunologic technique on whole skin homogenates, VIP levels were significantly increased in psoriatic lesions as compared to normal skin. By contrast, SP levels were significantly lower in lesional and non-lesional psoriatic skin than in normal skin. In addition, we examined the effect of VIP and SP on the proliferation of cultured normal human keratinocytes. VIP (1-28) (1 nM-1μM) as well as VIP fragments (10-28) (1 nM-1 μM) and (22-28) (1 nM-1μM) stimulated the proliferation of keratinocytes in a dose-dependent manner, whereas the VIP fragment (1-12) (1 nM-1 μM) was ineffective. The VIP antagonist (N-Ac-Tyr1, D-Phe2)-GRF (1-29)-NH2 (0.1 μM) significantly inhibited the VIP effect on keratinocytes. On the other hand, SP (0.1 μM) not only failed to stimulate keratinocyte growth, but also blocked the VIP-induced stimulation of these cells. The imbalance of cutaneous VIP and SP and their disparate effects on the proliferation of normal human keratinocytes in culture would suggest that these peptides are involved in the pathogenesis of psoriasis and may exert different modulatory activities in the mechanisms underlying the psoriatic lesion. © 1992
Alterations in vasoactive intestinal polypeptide-related peptides after pentylenetetrazole-induced seizures in rat brain
No full textThe possible involvement of vasoactive intestinal polypeptide-related peptides in pentylenetetrazol (PTZ)-induced seizures in rats was investigated. The chemoconvulsant PTZ was administered (45 mg/kg i.p.) either acutely or chronically for three days. The detailed time course of changes in VIP-(1-28) and VIP-(22-28) was examined in several rat brain areas 5 and 20 min and 24 h after acute treatment and after three days chronic treatment. Ir-VIP levels dramatically decreased in all areas 5 min after PTZ injection, remained low after 20 min and progressively increased back to control values after 24 h and after three days of repeated treatment (except for the cortex). Chromatographic analysis of extracts prepared from PTZ-treated rats revealed a concomitant decrease in VIP-(1-28) and increase in VIP-(22-28). Thus VIP-(22-28)might be a product of the internal cleavage of the precursor VIP-(1-28) after its neuronal release; alternatively, VIP-(22-28) might be generated by post-transcriptional processing of VIP-(1-28), and thus be an 'independent' neuropeptide. The results suggest VIP-(1-28)/VIP-(22-28)-containing neurons might be involved in PTZ-induced seizures in rat brain, and that VIP-(22-28) might play a role in these experimental seizures. © 1992
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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