1,721,272 research outputs found
Prodynorphin gene regulation by epigenetic mechanisms following ethanol and acetaldehyde exposure in SH-SY5Y cells
No full textThe role of acetaldehyde in mediating effects of alcohol on expression of endogenous opioid system genes in a neuroblastoma cell line
No full textEthanol (EtOH) alters neural activity through interaction with various neurotransmitters and neuromodulators. The endogenous opioid system seems to play a key role in the activities of EtOH, since the opioid antagonist naltrexone (ReVia) attenuates craving. We have investigated the transcriptional regulation of opioid system genes in response to EtOH exposure for up to 96 h in human neuroblastoma SH-SY5Y cells using quantitative real-time polymerase chain reaction. We observed a significant decrease in the expression of opioid peptide precursors (proopiomelanocortin, proenkephalin, and prodynorphin) and of the kappa opioid receptor after 48 and 72 h of EtOH exposure (10 and 40 mM). These alterations were not present when the EtOH metabolism was blocked by 4-methylpyrazole. To evaluate whether the effects evoked by EtOH were possibly due to the first product of EtOH metabolism, cells were exposed to 0.4 mM acetaldehyde. We observed the same pattern of changes for prodynorphin, proenkephalin, and the kappa opioid receptor as after 72 h exposure to EtOH. These results contribute to our understanding of EtOH action at a cellular level and provide evidence of the role of acetaldehyde in mediating some of the EtOH-induced effects
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
A role for epigenetic mechanisms in the regulation of prodynorphin expression by alcohol
No full textBackground and Aim: Alcohol alters several neurotransmitter
systems within the brain and accumulated
evidences indicate the endogenous opioid system as an
important target of its action. We studied, in vitro and in
vivo the molecular alterations occurring in the prodynorphin
gene following different exposures to alcohol.
Methods: Human neuroblastoma SH-SY5Y cells were
exposed to low, clearly not intoxicating, and high etha-
208
European Opioid Conference 2011, Kraków, Poland
nol concentrations at different time points. Sprague
Dawley rats received alcohol intragastrically trying to
mimic human drinking that establishes tolerance and dependence
conditions. Real-time RT-PCR was used to assess
the abundance of mRNAs of interest. DNA methylation
was analyzed by Methylation Specific-Real Time
PCR and bisulfite-Pyrosequencing. Specific histone
modifications at gene promoters were evaluated by
Chromatin ImmunoPrecipitation.
Results: In the cellular model we demonstrated
a temporal relationship between selective chromatin
modifications induced by ethanol or acetaldehyde,
and changes in prodynorphin gene expression were
demonstrated. In the amygdala complex of alcoholtreated
rats differential changes in prodynorphin gene
expression changes were observed depending on the
time of exposure; consistently, we propose potential
epigenetic mechanisms responsible for these alterations,
at least upong short ethanol exposure.
Conclusion: Our findings indicate a linkage between
gene expression alterations and epigenetic modulation
in prodynorphin promoter, thus adding novel information
on how the opioid system can be affected by alcohol
in several ways. Studies are ongoing to evaluate
the chromatin remodelling in the neuroplasticity occurring
in the progression of alcohol abuse. It will be
also of value to study the ability of epigenetic modulators
in reverting dynorphin genetic/epigenetic alterations
and alcohol abuse-related behaviours. Moreover,
opioid drugs already available in alcoholism treatment
could also have possible epigenetic modulating
properties
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
Fluorescence Correlation Spectroscopy (FCS) study of mu-opioid receptor dynamics in live cells
No full textA role for epigenetic mechanisms in the regulation of prodynorphin expression by alcohol
No full textNew strategies to study endogenous opioid system regulation in alcoholism: evaluation of ethanol mechanisms by molecular imaging, genetic and epigenetic analysis
No full textAppropriate 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
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