1,720,963 research outputs found
Similar sequence-free amplification of human glyceraldehyde-3- phosphate dehydrogenase for real time RT-PCR applications
No full textOne of the major applications of real time polymerase chain reaction (PCR) is
relative quantification, where the expression of a target gene is determined as a
ratio to a stably expressed reference gene, the so-called housekeeping gene.
Glyceraldehyde-3-phosphate dehydrogenase (GAPD) is a glycolytic enzyme, which is
active in all mammalian tissues and is frequently used as housekeeping gene in
expression studies. The functional locus maps to human chromosome 12p13, but
several GAPD-related sequences, including processed pseudogenes, GenBank
homologous sequences and computationally predicted sequences are present along
the human genome. Due to the high level of GAPD-related sequences it is very
important to avoid genomic DNA amplification when GAPD is used as endogenous
control in mRNA quantification. We have outlined a GAPD couple of primers that
avoid any genomic DNA amplification for real time reverse transcription PCR
applications by SYBR-Green Dye. These new designed primers are an useful and chip
alternative to probe technologies, and can carry out specific and reproducible
data in mRNA expression studies
Expression of adrenomedullin and its receptors in the human adrenal cortex and aldosteronomas
No full textAdrenomedullin (ADM) is a hypotensive peptide, that derives from the proteolytic cleavage of pro(p)ADM and acts through at least two subtypes of receptors, called L1-receptor (L1-R) and calcitonin receptor-like receptor (CRLR). CRLR may function as a calcitonin gene-related peptide (CGRP) or a selective ADM receptor depending on the expression of the subtype 1 or the subtypes 2 and 3 of a family of proteins, referred to as receptor-activity-modifying proteins (RAMPs). Although adrenal cortex is known to be one of the main target organs of ADM, its expression of the ADM and its receptor has not yet been extensively investigated. Reverse transcription (RT)-polymerase chain reaction (PCR) revealed the expression of the pADM and peptidyl-glycine alpha-amidating monooxigenase (PAM) genes in four human adrenal cortexes and four aldosteronomas. Since PAM is the enzyme that converts immature ADM to the mature and active form, these findings suggest that the two tissues are able to produce ADM. RT-PCR also demonstrated high levels of L1-R mRNA and relatively low levels of CRLR mRNA, as well as the presence of specific mRNAs for the three RAMPs, thereby indicating that human adrenal cortex and aldosteronomas are provided with the two subtypes of classic ADM receptors. In conclusion, our investigation provides the first evidence that human adrenal cortex and aldosteronomas express the ADM system, that may play a role in the paracrine or autocrine control of their functions
Expression and function of adrenomedullin and its receptors in Conn's adenoma cells
No full textAdrenomedullin (ADM) is a hypotensive peptide, that derives from the proteolytic cleavage of pro(p)ADM and acts through two subtypes of receptors, called L1-receptor (L1-R) and calcitonin receptor-like receptor (CRLR). CRLR may function as a calcitonin gene-related peptide or a selective ADM receptor depending on the expression of the subtype 1 or the subtypes 2 and 3 of a family of proteins, named receptor-activity modifying proteins (RAMPs). Reverse transcription (RT)-polymerase chain reaction (PCR) allowed the detection of pADM mRNA in dispersed cells of eight Conn's adenomas (aldosteronomas). These cells also expressed peptidyl-glycine α-amidating monooxigenase, the enzyme converting immature ADM to the mature form, and contained sizeable amounts of ADM-immunoreactivity as measured by radioimmunoassay. RT-PCR also demonstrated the presence in aldosteronoma cells of the specific mRNAs of L1-R, CRLR and RAMPs 1-3. ADM (10-8 M) inhibited angiotensin-II (10-9 M)-simulated aldosterone secretion from cultured aldosteronoma cells, without affecting basal production. ADM (10-8 M) also enhanced basal proliferation rate of cultured cells, as estimated by the 5-bromo-2'-deoxyuridine immunocytochemical technique. Both effects of ADM were annulled by the ADM-receptor selective antagonist ADM22-52 (10-7 M). In conclusion, our study provides evidence that aldosteronoma cells express both ADM and ADM22-52-sensitive receptors. These findings, coupled with the demonstration that ADM exerts an aldosterone antisecretagogue action and a proliferogenic effect on cultured aldosteronoma cells, make it likely that endogenous ADM system plays a potentially important role in the paracrine or autocrine functional control of Conn's adenomas
Calcitonin gene-related peptide (CGRP), acting via CGRP type 1 receptors, inhibits potassium-stimulated aldosterone secretion and enhances basal catecholamine secretion from rat adrenal gland
No full textCalcitonin gene-related peptide (CGRP) is a potent hypotensive peptide, that acts via two main subtypes of receptors, named CGRP1 and CGRP2. CGRP belongs to a regulatory-peptide family, that includes adrenomedullin (ADM) whose aldosterone antisecretagogue and catecholamine secretagogue actions are well demonstrated. Quantitative autoradiography showed the presence of [125I]CGRP binding sites in both rat adrenal zona glomerulosa (ZG) and medulla. Binding was displaced by the CGRP1-receptor antagonist CGRP(8-37), but not by the CGRP2-receptor agonist [cys(Et)2,7]-alphaCGRP (CGRP2-A). CGRP concentration-dependently inhibited 10 mM-stimulated (but not basal) aldosterone secretion from dispersed rat ZG cells, and enhanced basal catecholamine secretion from rat adrenomedullary fragments. The responses to the maximal effective concentration of CGRP (10-8 M) were blocked by 10-7 M CGRP(8-37). CGRP2-A (10-7 M) neither altered aldosterone response to 10 mM K+ nor enhanced basal catecholamine secretion. The conclusion is drawn that CGRP, like ADM, inhibits agonist-stimulated aldosterone secretion and stimulates basal catecholamine release in the rat, exclusively acting via CGRP1 receptors
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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