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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

The Effects of Stress and Placebo Alcohol on Cognitive Activation and Inhibitory Control in Male Problem Drinkers and Healthy Controls

Tremblay, Anne-Marie 16 February 2010 (has links)
This study assessed the separate and combined effects of two important instigators of relapse, alcohol cues and stress, on the salience of alcohol target stimuli and inhibitory control, in 12 male problem drinkers and 16 male controls. Subjects underwent two test sessions where they received alcohol cues (non-alcoholic beer) and/or stress (uncontrollable noise) in a counterbalanced manner. Testing was carried out through validated, computer-based tasks: modified Stroop, gambling-word Shift task; and conventional and modified (Alcohol word) Stop-Signal tasks. Inhibitory control was preferentially impaired to Alcohol stimuli in both groups. Beer and stress in combination increased incentive salience of Alcohol stimuli and moderated self-reported desire for alcohol in problem drinkers but not controls. Results suggest that alcohol cues and stress have interactive effects on subjective motivation, and disinhibit behaviour due to distraction in problem drinkers. Findings from this paradigm may improve understanding and facilitate treatment for relapse prevention in problem drinkers.
72

The Effects of Stress and Placebo Alcohol on Cognitive Activation and Inhibitory Control in Male Problem Drinkers and Healthy Controls

Tremblay, Anne-Marie 16 February 2010 (has links)
This study assessed the separate and combined effects of two important instigators of relapse, alcohol cues and stress, on the salience of alcohol target stimuli and inhibitory control, in 12 male problem drinkers and 16 male controls. Subjects underwent two test sessions where they received alcohol cues (non-alcoholic beer) and/or stress (uncontrollable noise) in a counterbalanced manner. Testing was carried out through validated, computer-based tasks: modified Stroop, gambling-word Shift task; and conventional and modified (Alcohol word) Stop-Signal tasks. Inhibitory control was preferentially impaired to Alcohol stimuli in both groups. Beer and stress in combination increased incentive salience of Alcohol stimuli and moderated self-reported desire for alcohol in problem drinkers but not controls. Results suggest that alcohol cues and stress have interactive effects on subjective motivation, and disinhibit behaviour due to distraction in problem drinkers. Findings from this paradigm may improve understanding and facilitate treatment for relapse prevention in problem drinkers.
73

Parathyroid Hormone Regulates Osterix Promoter Activity In Vitro and Expression In Vivo

Barbuto, Richard 01 December 2011 (has links)
Osterix (Osx) is a transcription factor required for osteoblast differentiation and bone formation. We previously demonstrated that continuous parathyroid hormone (PTH) treatment inhibited Osx expression in murine calvaria and osteoblastic UMR106-01 cells through the regulation of two regions on the Osx promoter. Mutational analysis of transcription factor elements within these regions revealed two "Sp-sites" were vital for Osx promoter activity. Blockage of these Sp-sites with Mithramycin A demonstrated their importance for Osx expression. Osx bound to its own promoter at these sites, while PTH treatment inhibited this association. PTH regulation of Osx expression in vivo was investigated in mice by: daily injection of PTH for 3 days, continuous infusion of PTH from osmotic pumps for 14 days, or mice fed a calcium-deficient diet for 21 days. Osx expression was decreased by daily injection, while Osx expression was stimulated in mice receiving continuous PTH infusion and mice fed a calcium-deficient diet.
74

The Anticonvulsant Effects of Docosahexaenoic Acid in Rodents

Trepanier, Marc-Olivier 02 January 2012 (has links)
Introduction: One potential new therapy for epilepsy involves the omega-3 polyunsaturated fatty acids (PUFAs), and more specifically docosahexaenoic acid (DHA).   Methods: The anticonvulsant properties of the n-3 PUFAs were assessed in a series of different experiments. Subjects received chronic dietary supplementation, sub-chronic and acute injections of either fish oil (chronic) or DHA (sub-chronic, acute). Animals were tested in the electrical afterdischarge thresholds (ADTs) model in the amygdale and the maximal pentylenetetrazol (PTZ) model.   Results: Chronic, sub-chronic, and acute administrations of n-3 PUFAs were anticonvulsant in both the electrical stimulation and maximal PTZ models. In chronic experiments, amygala ADTs increased following 3 months of fish oil administration. Fourteen days of DHA i.p. injections increased latencies to maximal PTZ seizures. Acute injection of DHA s.c. and i.v. increased unesterified serum DHA and seizure latency. Conclusions: The present research suggests that n-3 PUFAs, and more specifically DHA, have anticonvulsant effects in vivo.
75

Measurement of Spine Density in Mouse Models of Hypodopaminergia

Bermejo, Marie Kristel 11 July 2013 (has links)
Dopamine (DA) is a key catecholamine neurotransmitter involved in motor control, cognition, and neuroendocrine regulation. Reduced DA transmission is associated with Parkinson’s disease, depression, and anhedonia. An overexpression of the dopamine transporter in mice (DAT-tg) results in a 40% reduction in extracellular DA, and can be classified as a genetic model of hypodopaminergia. Reserpine treatment depletes extracellular DA, and is a pharmacological model of hypodopaminergia. The aim of this study was to determine morphological and proteomic changes to medium spiny neurons (MSNs), which receive dopaminergic input, as a consequence of reduced DA transmission. To achieve this, MSNs were fluorescently labelled using a diolistics method and immunofluorescence. There were no observable changes to morphology or proteomic profile of MSNs in DAT-tg animals. Reserpine treatment resulted in reduced spine density in MSNs. DAT-tg animals may present a level of DA depletion that is below the threshold to induce morphological changes to MSNs.
76

Genetic Variations Associated with Resistance to Doxorubicin and Paclitaxel in Breast Cancer

Ibrahim-zada, Irada 05 December 2012 (has links)
Anthracycline- and taxane-based regimens have been the mainstay in treating breast cancer patients using chemotherapy. Yet, the genetic make-up of patients and their tumors may have a strong impact on tumor sensitivity to these agents and to treatment outcome. This study represents a new paradigm assimilating bioinformatic tools with in vitro model systems to discover novel genetic variations that may be associated with chemotherapy response in breast cancer. This innovative paradigm integrates drug response data for the NCI60 cell line panel with genome-wide Affymetrix SNP data in order to identify genetic variations associated with drug resistance. This genome wide association study has led to the discovery of 59 candidate loci that may play critical roles in breast tumor sensitivity to doxorubicin and paclitaxel. 16 of them were mapped within well-characterized genes (three related to doxorubicin and 13 to paclitaxel). Further in silico characterization and in vitro functional analysis validated their differential expression in resistant cancer cell lines treated with the drug of interest (over-expression of RORA and DSG1, and under-expression of FRMD6, SGCD, SNTG1, LPHN2 and DCT). Interestingly, three and six genes associated with doxorubicin and paclitaxel resistance, respectively, are involved in the apoptotic process in cells. A constructed interactome suggested that there is cross-talk at the Nrf-2 oxidative stress pathway between genes associated with resistance to doxorubicin and paclitaxel. This unique GWA approach serves as a proof-of-principle study and systematically investigates targets responsible for variable response to chemotherapy in breast tumor cells and possibly the tumors of breast cancer patients. Overall, the model discovered novel candidate genes that have not been previously associated with doxorubicin and paclitaxel cytotoxicity. Future studies will be directed at illustrating a causative relationship between the observed genomic changes and drug resistance in breast cancer patients undergoing doxorubicin and paclitaxel chemotherapy.
77

Parathyroid Hormone Regulates Osterix Promoter Activity In Vitro and Expression In Vivo

Barbuto, Richard 01 December 2011 (has links)
Osterix (Osx) is a transcription factor required for osteoblast differentiation and bone formation. We previously demonstrated that continuous parathyroid hormone (PTH) treatment inhibited Osx expression in murine calvaria and osteoblastic UMR106-01 cells through the regulation of two regions on the Osx promoter. Mutational analysis of transcription factor elements within these regions revealed two "Sp-sites" were vital for Osx promoter activity. Blockage of these Sp-sites with Mithramycin A demonstrated their importance for Osx expression. Osx bound to its own promoter at these sites, while PTH treatment inhibited this association. PTH regulation of Osx expression in vivo was investigated in mice by: daily injection of PTH for 3 days, continuous infusion of PTH from osmotic pumps for 14 days, or mice fed a calcium-deficient diet for 21 days. Osx expression was decreased by daily injection, while Osx expression was stimulated in mice receiving continuous PTH infusion and mice fed a calcium-deficient diet.
78

The Anticonvulsant Effects of Docosahexaenoic Acid in Rodents

Trepanier, Marc-Olivier 02 January 2012 (has links)
Introduction: One potential new therapy for epilepsy involves the omega-3 polyunsaturated fatty acids (PUFAs), and more specifically docosahexaenoic acid (DHA).   Methods: The anticonvulsant properties of the n-3 PUFAs were assessed in a series of different experiments. Subjects received chronic dietary supplementation, sub-chronic and acute injections of either fish oil (chronic) or DHA (sub-chronic, acute). Animals were tested in the electrical afterdischarge thresholds (ADTs) model in the amygdale and the maximal pentylenetetrazol (PTZ) model.   Results: Chronic, sub-chronic, and acute administrations of n-3 PUFAs were anticonvulsant in both the electrical stimulation and maximal PTZ models. In chronic experiments, amygala ADTs increased following 3 months of fish oil administration. Fourteen days of DHA i.p. injections increased latencies to maximal PTZ seizures. Acute injection of DHA s.c. and i.v. increased unesterified serum DHA and seizure latency. Conclusions: The present research suggests that n-3 PUFAs, and more specifically DHA, have anticonvulsant effects in vivo.
79

Measurement of Spine Density in Mouse Models of Hypodopaminergia

Bermejo, Marie Kristel 11 July 2013 (has links)
Dopamine (DA) is a key catecholamine neurotransmitter involved in motor control, cognition, and neuroendocrine regulation. Reduced DA transmission is associated with Parkinson’s disease, depression, and anhedonia. An overexpression of the dopamine transporter in mice (DAT-tg) results in a 40% reduction in extracellular DA, and can be classified as a genetic model of hypodopaminergia. Reserpine treatment depletes extracellular DA, and is a pharmacological model of hypodopaminergia. The aim of this study was to determine morphological and proteomic changes to medium spiny neurons (MSNs), which receive dopaminergic input, as a consequence of reduced DA transmission. To achieve this, MSNs were fluorescently labelled using a diolistics method and immunofluorescence. There were no observable changes to morphology or proteomic profile of MSNs in DAT-tg animals. Reserpine treatment resulted in reduced spine density in MSNs. DAT-tg animals may present a level of DA depletion that is below the threshold to induce morphological changes to MSNs.
80

The Role of Dopamine in Cue-induced Craving: A [11C]-(+)-PHNO PET Study in Tobacco-dependent Smokers

Chiuccariello, Lina 13 January 2010 (has links)
Environmental stimuli associated with drug use are related to drug craving and relapse. The mechanism of cue-induced craving is thought to involve the release of dopamine (DA) in brain regions associated with reward and habit formation. The aim of the study was to investigate the role of DA in cue-induced craving in tobacco-dependent smokers using Positron Emission Tomography (PET) and a picture cue paradigm. Tobacco-associated cues were capable of eliciting significantly greater subjective reports of craving relative to neutral cues in tobacco smokers (n=6) in a neuroimaging environment. Using this cue paradigm and [11C]-(+)-PHNO PET (n=6), a non-significant trend towards a greater decrease in binding potential, indicative of dopamine release, was shown in selected brain regions of interest. These findings are similar to findings in cocaine-dependent individuals and suggest the involvement of dopamine in the response to smoking-associated cues in tobacco-dependent individuals.

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