1,720,976 research outputs found
Trace amine-associated receptors and their ligands
No full textClassical biogenic amines (adrenaline, noradrenaline, dopamine, serotonin and histamine) interact with specific families of
G protein-coupled receptors (GPCRs). The term ‘trace amines’ is used when referring to p-tyramine, b-phenylethylamine,
tryptamine and octopamine, compounds that are present in mammalian tissues at very low (nanomolar) concentrations.
The pharmacological effects of trace amines are usually attributed to their interference with the aminergic pathways, but
in 2001 a new gene was identified, that codes for a GPCR responding to p-tyramine and b-phenylethylamine but not to
classical biogenic amines. Several closely related genes were subsequently identified and designated as the trace amineassociated
receptors (TAARs). Pharmacological investigations in vitro show that many TAAR subtypes may not respond to
p-tyramine, b-phenylethylamine, tryptamine or octopamine, suggesting the existence of additional endogenous ligands.
A novel endogenous thyroid hormone derivative, 3-iodothyronamine, has been found to interact with TAAR1 and possibly
other TAAR subtypes. In vivo, micromolar concentrations of 3-iodothyronamine determine functional effects which are
opposite to those produced on a longer time scale by thyroid hormones, including reduction in body temperature and
decrease in cardiac contractility. Expression of all TAAR subtypes except TAAR1 has been reported in mouse olfactory
epithelium, and several volatile amines were shown to interact with specific TAAR subtypes. In addition, there is evidence that
TAAR1 is targeted by amphetamines and other psychotropic agents, while genetic linkage studies show a significant
association between the TAAR gene family locus and susceptibility to schizophrenia or bipolar affective disorder.
British Journal of Pharmacology (2006) 149, 967–978. doi:10.1038/sj.bjp.0706948; published online 6 November 200
Modulation of cardiac inotropic state by 3-iodothyronamine: evidence for a novel signalling pathway mediated by trace amine-associated receptors
No full text
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
Modulation of cardiac ionic homeostasis by 3-iodothyronamine
No full text3-iodothyronamine (T(1)AM) is a novel endogenous relative of thyroid hormone, able to interact with trace amine-associated receptors, a class of plasma membrane G protein-coupled receptors, and to produce a negative inotropic and chronotropic effect. In the isolated rat heart 20-25 microM T(1)AM decreased cardiac contractility, but oxygen consumption and glucose uptake were either unchanged or disproportionately high when compared to mechanical work. In adult rat cardiomyocytes acute exposure to 20 microM T(1)AM decreased the amplitude and duration of the calcium transient. In patch clamped cardiomyocytes sarcolemmal calcium current density was unchanged while current facilitation by membrane depolarization was abolished consistent with reduced sarcoplasmic reticulum (SR) calcium release. In addition, T(1)AM decreased transient outward current (I(to)) and I(K1) background current. SR studies involving 20 microM T(1)AM revealed a significant decrease in ryanodine binding due to reduced B(max), no significant change in the rate constant of calcium-induced calcium release, a significant increase in calcium leak measured under conditions promoting channel closure, and no effect on oxalate-supported calcium uptake. Based on these observations we conclude T(1)AM affects calcium and potassium homeostasis and suggest its negative inotropic action is due to a diminished pool of SR calcium as a result of increased diastolic leak through the ryanodine receptor, while increased action potential duration is accounted for by inhibition of I(to) and I(K1) currents
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
- …
