1,721,003 research outputs found
Rat strains that differ in corticotropin-releasing hormone production exhibit different sleep-wake responses to interleukin 1
No full textCorticotropin-releasing hormone (CRH) is a mediator of responses to a variety of stressors, including immune challenge. CRH and the hypothalamic-pituitary-adrenal (HPA) axis constitute a negative feedback mechanism for actions of immunomodulators, such as interleukin (IL) 1. CRH is a potent inducer of waking, whereas IL-1 induces slow-wave sleep (SWS). We hypothesize that the complex changes in sleep-wake behavior during immune challenge are mediated in part by CRH and its antagonism of IL-1-induced enhancement of SWS. To further explore this hypothesis, we administered IL-1 intracerebroventricularly into rats of genetically related strains that differ in CRH/HPA axis responsiveness to IL-1 and determined subsequent alterations in their sleep-wake behavior. Sprague-Dawley rats responded to central administration of IL-1 with alterations in sleep-wake behavior as previously reported; SWS increased, and rapid eye movement sleep (REMS) and waking decreased. CRH and the HPA axis of Lewis rats are reported to be hyporesponsive to challenge; the onset of the IL-1-induced increase in SWS was quicker and the peak magnitude of the response greater than in Sprague-Dawley rats. In contrast, Fischer 344 rats exhibit greater CRH release and HPA axis activation in response to IL-1. IL-1 induced a profound and transient increase in waking of Fischer 344 rats before SWS increased. The febrile responses to IL-1 of Fischer 344 and Lewis rats were identical and of greater magnitude than those observed in Sprague-Dawley rats. Pretreatment with the CRH receptor antagonist -helical CRH(9-41) blocked the initial IL-1-induced increase in waking of Fischer 344 rats. CRH receptor blockade did not affect the IL-1-induced alterations in sleep-wake behavior of Lewis or Sprague-Dawley rats or brain temperature of any rat strain. These observations support the hypothesis that CRH is both a modulator of responses to IL-1 and is involved in the regulation of waking
Serotonergic activation stimulates the pituitary-adrenal axis and alters interleukin-1 mRNA expression in rat brain
No full textInteractions between neurotransmitters and immunomodulators within the central nervous system may be functionally relevant for communication between the immune system and the brain. Previous studies indicate that cytokines such as interleukin-1 (IL-1) alter activity of the serotonergic system at multiple levels. This study tested the hypothesis that serotonergic activation modulates cytokine mRNA expression in brain. Serotonergic activation was induced by injecting rats intraperitoneally (i.p.) prior to dark onset with the serotonin precursor -5-hydroxytryptophan (5-HTP; 100 mg/kg). Cytokine mRNA expression in discrete brain regions at selected time points was determined by means of ribonuclease protection assay. Plasma corticosterone concentrations were also measured to determine if the hypothalamic-pituitary-adrenal axis is activated in response to this treatment, which potentially could exert feedback regulating cytokine message expression in brain. Plasma corticosterone was elevated for 4 h after 5-HTP administration. At this time IL-1a mRNA expression was reduced in the hippocampus, hypothalamus, and brainstem, and IL-1b mRNA was reduced in the hippocampus. Six hours after 5-HTP injection, IL-1b mRNA increased in the hypothalamus. These results show that activation of the serotonergic system affects cytokine message expression in rat brain, possibly by actions of corticosterone
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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