1,721,008 research outputs found
Acetyl salmon endorphin-like and interrenal stress response in male gilthead seabream, Sparus aurata
No full textAcetyl salmon endorphin-like and interrenal stress response in male gilthead sea bream, Sparus aurata
No full textThe present study investigates the role of melanotrope proopiomelanocortinderived peptide in the interrenal stress response to different stressors in male gilthead sea bream, Sparus aur ata. Plasma cortisol and acetyl salmon endorphin (acetyl s-EP), as well as pituitary acetyl s-EP contents, were measured during two stress paradigms: (a) long-term (l-month) confinement and crowding, and (b) short-term (60-min) confinement, crowding, and manipulation. In addition, naltrexone, a highly specific opioid receptor antagonist, was employed in some experimental groups to evaluate the adaptability of the opioid response to interrenal stress. In the long-term (I-month) confinement and crowding, higher plasma cortisol levels and acetyl s-EP concentrations than in the control group were found. However, although plasma cortisol levels significantly increased in both types of stress paradigm, a significant rise in plasma acetyl s-EP was observed only in the case of confinement plus crowding. These data seem to suggest a direct correlation of acetyl s-EP plasma levels exclusively in cases of specific stress, and support previous observations about the different nature of the pituitary-interrenal stress response in salmonids and in mammals. The results obtained in the short-term (60-min) experiments demonstrate the double activation of both the opioid and corticotrope systems when manipulation plus crowding was applied
Expression of pro-opiomelanocortin gene in human ovarian tissue
No full textThe high concentration of pro-opiomelanocortin (POMC)-derived peptides in human follicular fluid, which is several times higher than in plasma, suggested a local expression of the POMC gene. This has previously been observed in the animal ovaries. Peripheral POMC-like mRNAs are not translated in POMC-derived peptides but recent evidence supports the presence of a small amount of full-length transcript in human testes and lymphocytes. The purpose of this study was to test two hypotheses: firstly, that there is a different pattern of POMC mRNA expression in the human ovary of fertile and post-menopausal women, and secondly that there is a tissue-specific localization of POMC transcript. Northern blot analysis showed that a potential relationship exists between POMC gene expression and the reproductive age of a woman, and that POMC mRNA has a tissue-specific localization. The expression of POMC messenger in the ovarian parenchyma collected from women of fertile age and in the germinative follicles appeared higher than that observed in samples from post-menopausal women. No signals were detected in corpora lutea. In conclusion, we believe that the physiological role of the POMC gene in the human ovary remains an unsolved problem, necessitating more sensitive methods of mRNA detection as well as further studies in vitro
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
Activin at parturition: changes of maternal serum levels and evidence for binding sites in placenta and fetal membranes
No full textOBJECTIVE:
To evaluate maternal serum activin A levels in pregnant women at parturition, correlated to the mode of delivery, and to localize activin receptor messenger RNA in human placenta and fetal membranes.
METHODS:
A specific two-site enzyme-linked immunosorbent assay (ELISA) was used to measure maternal activin A levels. Activin receptor mRNA was localized in placenta and fetal membranes by in situ hybridization, using ActRII or ActRIIB antisense riboprobes.
RESULTS:
Serum activin A levels increased significantly in pregnant women during vaginal or cesarean delivery after spontaneous labor. No significant changes of serum activin A were found in patients undergoing elective cesarean delivery. Syncytiotrophoblast and amnion cells hybridized to radiolabeled ActRIIB probe, whereas few cells within the structure of the villi and decidual cells hybridized to radiolabeled ActRII probe.
CONCLUSION:
The present studies indicate that vaginal or cesarean delivery following spontaneous labor is characterized by increased activin A levels and that activin receptors are present on trophoblast and fetal membranes
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