40,037 research outputs found
Attachment styles as predictors of Facebook-related jealousy and surveillance in romantic relationships
This is the post-print of the Article. The official published version can be accessed from the link below - Copyright @ 2012 John Wiley & SonsFacebook has become ubiquitous over the past five years, yet few studies have examined its role within romantic relationships. In two studies, we tested attachment anxiety and avoidance as predictors of Facebook-related jealousy and surveillance (i.e., checking a romantic partner’s Facebook page). Study 1 found that anxiety was positively associated, and avoidance negatively associated, with Facebook jealousy and surveillance. The association of anxiety with Facebook jealousy was mediated in part by lower trust. Study 2 replicated this finding, and daily diary results further showed that over a one-week period, anxiety was positively associated, and avoidance negatively associated, with Facebook surveillance. The association of anxiety with greater surveillance was mediated in part by daily experiences of jealousy
DISCOVERY OF NOVEL PHARMACOTHERAPEUTICS FOR SUBSTANCE USE DISORDERS
Substance use disorders are serious health concerns in the United States. Furthermore, the National Survey on Drug Use and Health reports a continuous increase in substance use disorders in the United States during the last 10 years. However, there are not many effective pharmacotherapeutics available for substance use disorders. The current dissertation is focused on research aimed at discovering pharmacotherapeutics for substance use disorders. First part of dissertation focused on discovering methamphetamine (METH) use disorder therapeutics targeting specific mechanism of METH action on dopaminergic neurons. The second part of dissertation focused on opioids and cocaine use disorder therapeutics targeting rewarding pathway commonly activated by opioids and cocaine.
With respect to METH, it induces release of dopamine (DA) in neuronal terminals by interacting with the vesicular monoamine transporter-2 (VMAT2) and DA transporter (DAT). VMAT2 inhibitors have been found by our research group to decrease METH-evoked DA release, METH-induced hyperlocomotion, and METH self-administration in rats. However, these VMAT2 inhibitors lacked selectivity and tolerance developed to these pharmacologic effects after repeated administration, thereby limiting their potential as pharmacotherapeutics for METH use disorders. In the current study, analogs from a novel scaffold were found to selectively inhibit VMAT2 and were evaluated using neurochemical and behavioral pharmacological approaches. R- and S-3-(4-methoxyphenyl)-N-(1-phenylpropan-2-yl)propan-1-amine (GZ-11610 and GZ-11608, respectively) exhibited 94- to 3450-fold selectivity for VMAT2 over human-ether-a-go-go (hERG) channel, DAT, serotonin transporter, and nicotinic acetylcholine receptors. GZ-11608 competitively and concentration-dependently inhibited METH-evoked DA release via VMAT2. Also, GZ-11610 (56-300 mg/kg, oral) and GZ-11608 (300 mg/kg, oral; 10-30 mg/kg, s.c.) reduced METH-induced hyperlocomotor activity in METH-sensitized rats. Furthermore, GZ-11608 (1-30 mg/kg, s.c.) inhibited METH self-administration, cue- and METH-induced reinstatement in a dose-dependent manner, and 30 mg/kg (s.c.), 10 mg/kg (s.c.), and 17 mg/kg (s.c.) produced significant effect, respectively. Importantly, the GZ-11608-induced decrease in METH self-administration was not surmounted by increasing the amount of METH available. GZ-11608 did not substitute for METH and did not serve as a reinforcer in rats self-administering METH and drug naïve rats, respectively. Thus, these VMAT2 inhibitors incorporating a new scaffold are novel leads for new pharmacotherapeutics to treat METH use disorders.
Substances with high abuse potential including opioids and cocaine elevate extracellular DA concentration in the nucleus accumbens, and this mechanism has long been considered to underly substance-induced reward. DA in the nucleus accumbens originates from DA neuron cell bodies located in the ventral tegmental area in the midbrain. Interestingly, M5 muscarinic acetylcholine receptors (mAChRs) are proteins that are highly expressed on ventral tegmental area DA neurons. Also, studies investigating M5 mAChRs knockout mice showed reduced responding for cocaine in cocaine self-administration and decreased time spent in cocaine-paired and morphine-paired place preference studies. Pharmacological inhibition of M5 mAChRs function via microinfusing mAChR antagonists exhibiting no selectivity among M1-M5 mAChRs subtypes into the ventral tegmental area where expression of M5 mAChRs are dominant, reduced morphine-induced hyperlocomotion and cocaine seeking behaviors in rats. These studies support therapeutic potential of M5 mAChRs selectivity antagonists in opioids and cocaine use disorders. Thus, in the current study, affinity of a series of pethidine and quinuclidinyl N-phenylcarbamate analogs for M5 mAChRs was evaluated using in vitro and ex vivo neuropharmacological assays. Among the pethidine analogs, compound 6a showed the highest binding affinity at M5 (Ki = 0.38 µM), but also high affinity at M1 and M3 mAChRs (0.67 and 0.37 µM, respectively). Among the quinuclidinyl N-phenylcarbamate analogs, compound 13c exhibited the highest affinity at M5 (Ki = 1.8 nM), but also high affinity at M1, M2, M3 and M4 mAChRs (Ki = 1.6, 13, 2.6, 2.2 nM, respectively). Also, 13c acted as an agonist of mAChRs on oxotremorine-induced DA release from rat striatal slices. In addition, compound 13b was found exhibiting the highest selectivity (17-fold) at M3 over M2 mAChRs, suggesting potential of 13b as a chronic obstructive pulmonary disease therapeutics. Taken together, these novel analogs serve as leads for further discovery of subtype-selective M5 mAChR antagonists that may have potential as therapeutics for substance use disorders, as well as for chronic obstructive pulmonary disease
Biphasic euchromatin-to-heterochromatin transition on the KSHV genome following de novo infection.
The establishment of latency is an essential step for the life-long persistent infection and pathogenesis of Kaposi's sarcoma-associated herpesvirus (KSHV). While the KSHV genome is chromatin-free in the virions, the viral DNA in latently infected cells has a chromatin structure with activating and repressive histone modifications that promote latent gene expression but suppress lytic gene expression. Here, we report a comprehensive epigenetic study of the recruitment of chromatin regulatory factors onto the KSHV genome during the pre-latency phase of KSHV infection. This demonstrates that the KSHV genome undergoes a biphasic chromatinization following de novo infection. Initially, a transcriptionally active chromatin (euchromatin), characterized by high levels of the H3K4me3 and acetylated H3K27 (H3K27ac) activating histone marks, was deposited on the viral episome and accompanied by the transient induction of a limited number of lytic genes. Interestingly, temporary expression of the RTA protein facilitated the increase of H3K4me3 and H3K27ac occupancy on the KSHV episome during de novo infection. Between 24-72 hours post-infection, as the levels of these activating histone marks declined on the KSHV genome, the levels of the repressive H3K27me3 and H2AK119ub histone marks increased concomitantly with the decline of lytic gene expression. Importantly, this transition to heterochromatin was dependent on both Polycomb Repressive Complex 1 and 2. In contrast, upon infection of human gingiva-derived epithelial cells, the KSHV genome underwent a transcription-active euchromatinization, resulting in efficient lytic gene expression. Our data demonstrate that the KSHV genome undergoes a temporally-ordered biphasic euchromatin-to-heterochromatin transition in endothelial cells, leading to latent infection, whereas KSHV preferentially adopts a transcriptionally active euchromatin in oral epithelial cells, resulting in lytic gene expression. Our results suggest that the differential epigenetic modification of the KSHV genome in distinct cell types is a potential determining factor for latent infection versus lytic replication of KSHV
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Distributions of brominated organic compounds in the troposphere and lower stratosphere
A comprehensive suite of brominated organic compounds was measured from whole air samples collected during the 1996 NASA Stratospheric Tracers of Atmospheric Transport aircraft campaign and the 1996 NASA Global Tropospheric Experiment Pacific Exploratory Mission-Tropics aircraft campaign. Measurements of individual species and total organic bromine were utilized to describe latitudinal and vertical distributions in the troposphere and lower stratosphere, fractional contributions to total organic bromine by individual species, fractional dissociation of the long-lived species relative to CFC-11, and the Ozone Depletion Potential of the halons and CH3Br. Spatial differences in the various organic brominated compounds were related to their respective sources and chemical lifetimes. The difference between tropospheric mixing ratios in the Northern and Southern Hemispheres for halons was approximately equivalent to their annual tropospheric growth rates, while the interhemispheric ratio of CH3Br was 1.18. The shorter-lived brominated organic species showed larger tropospheric mixing ratios in the tropics relative to midlatitudes, which may reflect marine biogenic sources. Significant vertical gradients in the troposphere were observed for the short-lived species with upper troposphere values 40-70% of the lower troposphere values. Much smaller vertical gradients (3-14%) were observed for CH3Br, and no significant vertical gradients were observed for the halons. Above the tropopause, the decrease in organic bromine compounds was found to have some seasonal and latitudinal differences. The combined losses of the individual compounds resulted in a loss of total organic bromine between the tropopause and 20 km of 38-40% in the tropics and 75-85% in midlatitudes. The fractional dissociation of the halons and CH3Br relative to CFC-11 showed latitudinal differences, with larger values in the tropics. Copyright 1999 by the American Geophysical Union
ciliaFA : a research tool for automated, high-throughput measurement of ciliary beat frequency using freely available software
Background: Analysis of ciliary function for assessment of patients suspected of primary ciliary dyskinesia (PCD) and
for research studies of respiratory and ependymal cilia requires assessment of both ciliary beat pattern and beat
frequency. While direct measurement of beat frequency from high-speed video recordings is the most accurate and
reproducible technique it is extremely time consuming. The aim of this study was to develop a freely available
automated method of ciliary beat frequency analysis from digital video (AVI) files that runs on open-source software
(ImageJ) coupled to Microsoft Excel, and to validate this by comparison to the direct measuring high-speed video
recordings of respiratory and ependymal cilia. These models allowed comparison to cilia beating between 3 and 52 Hz.
Methods: Digital video files of motile ciliated ependymal (frequency range 34 to 52 Hz) and respiratory epithelial cells
(frequency 3 to 18 Hz) were captured using a high-speed digital video recorder. To cover the range above between 18
and 37 Hz the frequency of ependymal cilia were slowed by the addition of the pneumococcal toxin pneumolysin.
Measurements made directly by timing a given number of individual ciliary beat cycles were compared with those
obtained using the automated ciliaFA system.
Results: The overall mean difference (± SD) between the ciliaFA and direct measurement high-speed digital imaging
methods was −0.05 ± 1.25 Hz, the correlation coefficient was shown to be 0.991 and the Bland-Altman limits of
agreement were from −1.99 to 1.49 Hz for respiratory and from −2.55 to 3.25 Hz for ependymal cilia.
Conclusions: A plugin for ImageJ was developed that extracts pixel intensities and performs fast Fourier
transformation (FFT) using Microsoft Excel. The ciliaFA software allowed automated, high throughput measurement of
respiratory and ependymal ciliary beat frequency (range 3 to 52 Hz) and avoids operator error due to selection bias. We
have included free access to the ciliaFA plugin and installation instructions in Additional file 1 accompanying this
manuscript that other researchers may use
Identifying Risks in IT Projects for Developing Economies
The emergence of information technology (IT) projects for developing economies is becoming a trend, as developing economies are striving to achieve modernization and industrialization. The IT project environment in developing economies is complex and susceptible to the economies\u27 unique social, cultural, political, and financial contexts. This study proposes a framework for identifying the risks involved in IT projects for developing economies. For this, the study identifies unique characteristics of project management in the context of developing economies, which involve a broader stakeholder group, lack of precedence, infrastructural limitations, and cultural uniqueness. The study discusses how these characteristics shape project risk factors in terms of both internal (people, process, and technology) and environmental (legal and natural) elements of an IT project
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