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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.
41

Konsumtion av kosttillskott bland träningsaktiva : En kvantitativ undersökning om köns- och åldersskillnader och samband med träningsform

Strandberg Keijser, Alina January 2015 (has links)
Att konsumera kosttillskott ökar i dagens samhälle. Exempel på kosttillskott är energigivande tillskott, prestationshöjande tillskott samt vitaminer och mineraler. En sammanställning av enkätundersökningar i Sverige visar att 61 % av männen och 41 % av kvinnorna konsumerar kosttillskott. Träningsverksamma upplever att produkterna är välgörande och ger positiva effekter på träningen, trots att riskerna med konsumtion av kosttillskott är omdebatterat och ett delvis obeforskat område. Bland träningsverksamma inom styrketräning förekommer även konsumtion av dopningspreparat. Dopning innebär att påverka eller förändra prestationer med olika substanser. Det finns olika slags dopningspreparat och anabola androgena steroider (AAS) är vanligast. Prevalensen av AAS har ökat under 2000-talet. I uppsatsen redovisas omfattningen av konsumtion av kosttillskott och dopningspreparat i Västmanlands län. Köns- och åldersskillnader samt samband mellan konsumtion och träningsform redovisas. Analyser har genomförts på enkätdata från Västmanlands Idrottsförbund, utifrån deras arbete med anti-dopning i Västmanland. Resultaten visar att det är vanligast att män i 17 – 30 års ålder konsumerar kosttillskott. Sannolikheten för att ha en hög konsumtion av kosttillskott ökar vid styrketräning. Socialkognitiv teori används föra att tolka den sociala aspekten på konsumtionen och ger en djupare förståelse för hur beteendet att konsumera kosttillskott och/eller dopningspreparat kan uppstå hos en individ. / Consuming dietary supplements is common in today's society. Examples of dietary supplements is energizing supplements, performance enhancing supplements and vitamins and minerals. A compilation of surveys in Sweden show that 61% of men and 41% of women consume dietary supplements. Athletes are experiencing that the products are beneficial and provides positive effects on the performance, even though there is a lack of knowledge about all the risks of consuming dietary supplement and a field partly un-researched. Consumption of doping substances also occur among athletes. Doping means to affect or change the performance with various substances. There are different types of doping substances, where anabolic androgenic steroids (AAS) are the most common. The prevalence of AAS has increased during the 2000s. The prevalence of the consumption of dietary supplements and doping in Västmanlands län are presented in the present study. Results revealed differences in gender and age and the relationship between consumption and exercise. Analyses have been performed on data from Västmanland Sports Federation, which through its anti-doping work conducted a survey in Västmanlands län. The results show that it is most common among men between the ages 17 – 30 to consume dietary supplements and to consume a few times a week or more often. The likelihood of consuming dietary supplements increases with strength training. Social cognitive theory is being used to interpret the social aspect of consumption and provides a deeper understanding for how a behavior can be developed in an individual.
42

Genome-Wide Identification and Characterization of Stimulus-Responsive Enhancers in the Nervous System

Malik, Athar Naveed 08 June 2015 (has links)
During development, intrinsic genetic programs give rise to distinct cellular lineages through the establishment of cell type specific chromatin states. These distinct chromatin states instruct gene expression primarily through the genome-wide demarcation of enhancers. In addition to maintaining cellular identity, the chromatin state of a cell provides a platform for transcriptional responses to environmental signals. However, relatively little is known about the influence of extracellular stimuli on chromatin state at enhancers, and it is not clear which enhancers among the tens of thousands that have been recently identified function to drive stimulus-responsive transcription. In the nervous system, the chromatin state of terminally differentiated neurons not only maintains neuronal identity but also provides a platform for sensory experience-dependent gene expression, which plays a critical role in the development and refinement of neural circuits and in long-lasting changes in neuronal function that underlie learning, memory, and behavior. Using chromatin-immunoprecipitation followed by high through put sequencing (ChIP-Seq), we determined the effects of neuronal stimuli on the active chromatin landscape of mouse cortical neurons. We discover that stimulation with neuronal activity and brain derived neurotrophic factor (BDNF) cause rapid, widespread, and distinct changes in the acetylation of histone H3 lysine 27 (H3K27Ac) at thousands of enhancers throughout the neuronal genome. We find that functional stimulus-responsive enhancers can be identified by stimulus- inducible H3K27Ac, and we use this dynamic chromatin signature to discover neuronal enhancers that respond to neuronal activity, BDNF, or both stimuli. Finally, we investigate the transcriptional mechanisms underlying the function of stimulus responsive enhancers. We show that a subset of stimulus-responsive enhancers in the nervous system require the coordinated action of the stimulus-general transcription factor activator protein 1 (AP1) with additional stimulus-specific factors. Our studies reveal the genome-wide basis for transcriptional specificity in response to distinct neuronal stimuli. Furthermore, the comprehensive identification of neuronal activity and BDNF-dependent enhancers in cortical neurons provides a critical resource for elucidating the role of stimulus-responsive transcription in synaptic plasticity, learning and memory, behavior, and disease. Finally, the epigenetic signature of stimulus-inducible H3K27Ac may aid in the identification and study of stimulus- regulated enhancers in other tissues.
43

Nasal delivery of insulin with Pheroid technology / Tanile de Bruyn

De Bruyn, Tanile January 2006 (has links)
Approximately 350 million people worldwide suffer from diabetes mellitus (DM) and this number increases yearly. Since the discovery and clinical application of insulin in 1921, subcutaneous injections have been the standard treatment for DM. Because insulin is hydrophilic and has a high molecular weight and low bioavailability, this molecule is poorly absorbed if administered orally. The aim of this study is to evaluate nasal delivery systems for insulin, using Sprague Dawley rats as the nasal absorption model. Pheroid technology and N-trimethyl chitosan chloride (TMC) with different dosages of insulin (4, 8 and 12 IU/kg bodyweight insulin) was administered in the left nostril of the rat by using a micropipette. Pheroid technology is a patented (North-West University) carrier system consisting of a unique oil/water emulsion that actively transports drug actives through various physiological barriers. These formulations were administered nasally to rats in a volume of 100 p/kg bodyweight in different types of Pheroids (vesicles, with a size of 1.7 1 - 1.94 pm and microsponges, with a size of 5.7 1 - 8.25 pm). The systemic absorption of insulin was monitored by measuring arterial blood glucose levels over a period of 3 hours. The TMC formulation with 4 IU/kg insulin produced clinically relevant levels of insulin in the blood and as a result also the maximal hypoglycaemic effect. TMC is a quaternary derivative of chitosan and is able to enhance the absorption of various peptide drugs by opening tight junctions between epithelial cells. Pheroid formulations were also effective in lowering blood glucose levels but only at higher doses (8 and 12 IU/kg) of insulin. This study indicated that Pheroid rnicrosponges had a faster onset of action and a slightly better absorption of insulin when compared to Pheroid vesicles, but many more studies are needed in this field. Although the results of this study with absorption enhancers are encouraging, nasal insulin bioavailability is still very low, and the Pheroid formulations and long-term safety of nasal insulin therapy have yet to be investigated. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2007.
44

BEHAVIORAL INTENTIONS AND NONMEDICAL ANABOLIC STEROID USE AMONG NON INTERCOLLEGIATE ATHLETE MALES AGES 18-30

Enaker, Vitesh 01 January 2013 (has links)
The purpose of this study was to increase understanding of factors associated with nonmedical anabolic steroid use among males ages 18-30 who do not participate in intercollegiate athletics. The Behavioral Intentions and Ergogenic Aid/Performance Enhancer use among non-intercollegiate athlete males survey instrument was developed, reviewed for content validity by a jury of experts, and pilot tested. The pilot testing results (n=25) demonstrated acceptable reliability (Cronbach’s alpha= 0.74). The final version of the Behavioral Intentions and Ergogenic Aid/Performance Enhancer use among non-intercollegiate athlete males survey instrument was administered at two distribution sites which included Ford’s Fitness Center in Lexington, Kentucky and the Johnson Center on the University of Kentucky’s campus to non-intercollegiate athlete men between the ages of 18-30 (n=121). The final version of the survey instrument was also found to be reliable (Cronbach’s alpha= 0.86).Of the 121 respondents, 7 (5.9%) reported using nonmedical anabolic steroids at least 1-2 days a week or more. A total of 9 (7.4%) men reported intending to use nonmedical anabolic steroids within the next year. Age was found to have a statistically significant association with intention to use nonmedical anabolic steroids (p=.037).Perceived behavioral control (p=.029) was found to be the strongest predictor variable of study participants’ intention to use nonmedical anabolic steroids. Muscle mass builder use (p=.011) and muscle mass builder use in combination with multivitamin use (p=.000) were found to be significant predictors of actual nonmedical anabolic steroid use. Study participants were more likely to use nonmedical anabolic steroids if they were currently using a muscle mass builder or using a muscle mass builder in combination with a multivitamin. No decision about the effectiveness of the components of perceived behavioral control (self-efficacy and control) as a one or two part construct was possible because of the small number of study participants. Two additional demographic predictor variables were found to be statistically significant with predicting the intention to use nonmedical anabolic steroids. Being a competitive bodybuilder (p=.001) was positively correlated and being satisfied with body image (p=.025) was negatively correlated with the intention to use nonmedical anabolic steroids.
45

Nasal delivery of insulin with Pheroid technology / Tanile de Bruyn

De Bruyn, Tanile January 2006 (has links)
Approximately 350 million people worldwide suffer from diabetes mellitus (DM) and this number increases yearly. Since the discovery and clinical application of insulin in 1921, subcutaneous injections have been the standard treatment for DM. Because insulin is hydrophilic and has a high molecular weight and low bioavailability, this molecule is poorly absorbed if administered orally. The aim of this study is to evaluate nasal delivery systems for insulin, using Sprague Dawley rats as the nasal absorption model. Pheroid technology and N-trimethyl chitosan chloride (TMC) with different dosages of insulin (4, 8 and 12 IU/kg bodyweight insulin) was administered in the left nostril of the rat by using a micropipette. Pheroid technology is a patented (North-West University) carrier system consisting of a unique oil/water emulsion that actively transports drug actives through various physiological barriers. These formulations were administered nasally to rats in a volume of 100 p/kg bodyweight in different types of Pheroids (vesicles, with a size of 1.7 1 - 1.94 pm and microsponges, with a size of 5.7 1 - 8.25 pm). The systemic absorption of insulin was monitored by measuring arterial blood glucose levels over a period of 3 hours. The TMC formulation with 4 IU/kg insulin produced clinically relevant levels of insulin in the blood and as a result also the maximal hypoglycaemic effect. TMC is a quaternary derivative of chitosan and is able to enhance the absorption of various peptide drugs by opening tight junctions between epithelial cells. Pheroid formulations were also effective in lowering blood glucose levels but only at higher doses (8 and 12 IU/kg) of insulin. This study indicated that Pheroid rnicrosponges had a faster onset of action and a slightly better absorption of insulin when compared to Pheroid vesicles, but many more studies are needed in this field. Although the results of this study with absorption enhancers are encouraging, nasal insulin bioavailability is still very low, and the Pheroid formulations and long-term safety of nasal insulin therapy have yet to be investigated. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2007.
46

Functional Analysis of the Cis-Regulatory Elements I56i, I56ii and I12b that Control Dlx Gene Expression in the Developing Forebrain of Mouse and Zebrafish

Yu, Man 22 August 2011 (has links)
The vertebrate Dlx gene family consists of multiple convergently transcribed bigene clusters and encodes a group of homeodomain-containing transcription factors crucial for the development of forebrain, branchial arches, sensory organs and limbs. At least four cis-regulatory elements (CREs) are responsible for Dlx expression in the forebrain: URE2 and I12b in the Dlx1/Dlx2 (zebrafish dlx1a/dlx2a) locus, and, I56i and I56ii in the Dlx5/Dlx6 (zebrafish dlx5a/dlx6a) locus. Here, we first show that unlike the other three enhancers, mouse I56ii CRE targets a group of GABAergic projection neurons expressing striatal markers Meis2 and Islet1. Meis2 and Islet1 proteins can activate reporter gene transcription via the I56ii CRE, suggesting that they may be potential upstream regulators of Dlx genes in vivo. To determine whether there exists a dlx-mediated regulatory pathway during zebrafish GABAergic neuron formation, we establish two independent lines of transgenic fish in which the GFP reporter gene is controlled by a 1.4kb dlx5a/dlx6a intergenic sequence (encompassing zebrafish I56i and I56ii) and a 1.1kb fragment containing only I56i CRE, respectively. Our observations reveal that dlx5a/dlx6a regulatory elements exhibit a fairly specific activity in the zebrafish forebrain and may be essential for GABAergic neuron generation, while I56i and I56ii are likely to play distinct roles in modulating this process in different subpopulations of cells. Disruption of dlx1a/dlx2a or dlx5a/dlx6a function leads to a marked decrease of enhancer activity in the diencephalon and midbrain as well as a comparatively lesser extent of reduction in the telencephalon. In order to define the specific contribution of various individual CREs to overall Dlx regulation, we also generate a mutant mouse model in which I12b CRE is selectively deleted. Despite that mice homozygous for I12b loss develop normally and harbor no overt morphological defects in the forebrain, targeted deletion of this enhancer results in a significant reduction of Dlx1/Dlx2 transcript levels and seemingly perturbs cell proliferation in the subpallial telencephalon, particularly in the ventricular and subventricular zones of ganglionic eminences. Taken together, these data illustrate a complex and dynamic Dlx regulation in the early developing forebrain through the implications of multiple Dlx CREs with overlapping and diverse functions.
47

Functional Analysis of Dlx Intergenic Enhancers in the Developing Mouse Forebrain

Fazel Darbandi, Siavash 08 May 2014 (has links)
The Distal-less homeobox (Dlx) genes encode a group of transcription factors that are involved in various developmental processes including forebrain development. Dlx genes are arranged in convergently transcribed bigene clusters with enhancer sequences located in the intergenic region of each cluster. The expression patterns of Dlx1/Dlx2 and of Dlx5/Dlx6 are attributed in part to the activity of I12a/I12b and I56i/I56ii intergenic enhancers, respectively. In an effort to determine how Dlx intergenic enhancers interact with the promoter regions of each cluster, I employed the Chromosome Conformation Capture (3C) technique on developing forebrain at E13.5 and E15.5. My 3C analysis provided potential enhancer-promoter interaction, in cis, that are consistent with previously known regulatory mechanisms. Furthermore, trans interactions may exist between Dlx1/Dlx2 and Dlx5/Dlx6 clusters in the developing forebrain at E13.5, thus providing a possible novel cross-regulatory mechanism between these two loci. I have also investigated the phenotypic consequences of Dlx enhancer deletion(s) on forebrain development by characterizing mice with I56ii and I56ii/I12b enhancer deletions. Enhancer deletions significantly impair Dlx expression as well as that of Evf2, Gad2 and of the striatal markers Islet1 and Meis2. Enhancer deletion(s) also reduce the expression of ISLET1 and CTIP2 proteins and Semaphorin 3A, Slit1 and Ephrin A5 that are thought to provide guidance cues in the corridor cells. Overall, these changes may disrupt the guidance of the thalamocortical axons. The data presented here further our understanding of the interactions between Dlx intergenic enhancers and promoter regions. Enhancer deletion(s) furthers our understanding of Dlx regulatory networks necessary that ensure proper Dlx expression, which, in turn may be involved in a genetic pathway underlying the synthesis of GABA, which may be further essential in maintaining the GABAergic phenotype.
48

Formulace a (trans)dermální podání lipozómů s obsahem imiquimodu / Formulation and trans(dermal) delivery of liposomes containing imiquimod

Tirala, Petr January 2018 (has links)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Author: Petr Tirala Supervisor: PharmDr. Barbora Švecová, Ph.D. Title of thesis: Formulation and (trans)dermal application of liposomes containing imiquimod Imiquimod (IMQ), a substance belonging to the class of heterocyclic imidazoquinolines, shows significant immunomodulatory effects after topical administration, which is used to treat a variety of viral and malignant diseases of the skin. IMQ is currently used in clinical practice in the form of cream Aldara® containing 5% of active substance, which is unstable and irritating and after removal from the skin IMQ poses an ecological load for the environment. The aim of this thesis was preparation of liposomes for topical administrativ containing lower - 1% amount of IMQ and evaluation of penetration of IMQ into human skin in vitro. To improve the properties of liposomes and promote patency of the active ingredient through the skin barrier to the deeper skin layers various additives were used. Permeation experiments were carried out in Franz diffusion cells on the human skin in order to create the conditions that are as physiological as possible. Amount of IMQ was determined in the uppermost layer of the skin, epidermis, dermis, acceptor phase...
49

Neuropsychological and electrophysiological biomarkers of the schizophrenia spectrum

Koychev, Ivan January 2011 (has links)
Schizophrenia is a neuropsychiatric disorder lying at the extreme of a spectrum of disorders that possibly share a common abnormality in neural connectivity. Efforts to reverse the core cognitive manifestations of schizophrenia using drug treatments have so far been unsuccessful. This thesis investigates the cognitive abnormalities and their electrophysiological correlates across the schizophrenia spectrum in order to identify and validate biomarkers for proof of concept studies of cognitive enhancers. Such studies in milder disorders of the schizophrenia spectrum such as schizotypal personality trait may be a crucial method in identifying new effective compounds, as reviewed in Chapter 3, and tested in Chapter 4. The latter features the results of a large three-centre study which probed the sensitivity of several neuropsychological measures to the schizotypy phenotype, as well as to the effects of amisulpride, risperidone and nicotine. Schizotypal volunteers showed impaired performance only on the more difficult tasks. The most consistent pharmacological finding was that amisulpride tended to improve performance in the high schizotypy group but to impair it in the average schizotypy controls. One interpretation is that the ability of low dose amisulpride to enhance dopamine function in frontal cortex reversed an impairment of dopamine function present in the high schizotypes which is thought to occur in schizophrenia. Chapter 5 explored the methodological question of whether low or average schizotypy individuals should be used as controls in cognitive comparisons versus high schizotypy. The results suggest that low schizotypes have the most intact cognitive performance and are therefore the control group of choice. Chapters 6, 7 and 8 tested the hypothesis that cognitive deficits are part of a larger information processing abnormality in the schizophrenia spectrum. In accordance, both high schizotypy and schizophrenia patients exhibited reduced amplitude of an early visual evoked potential P1 (Chapters 6 and 8, respectively) and disruptions of the underlying evoked neural oscillations (Chapters 7 and 8). The pattern of abnormalities suggested an inefficient top-down modulation of perception in the schizophrenia spectrum. These data argue that cognitive abnormalities and their electrophysiological correlate may be sensitive biomarkers of the core dysconnectivity deficit in schizophrenia. This thesis supports their use in proof of concept studies to foster the development of cognitive enhancers.
50

Functional Analysis of the Cis-Regulatory Elements I56i, I56ii and I12b that Control Dlx Gene Expression in the Developing Forebrain of Mouse and Zebrafish

Yu, Man January 2011 (has links)
The vertebrate Dlx gene family consists of multiple convergently transcribed bigene clusters and encodes a group of homeodomain-containing transcription factors crucial for the development of forebrain, branchial arches, sensory organs and limbs. At least four cis-regulatory elements (CREs) are responsible for Dlx expression in the forebrain: URE2 and I12b in the Dlx1/Dlx2 (zebrafish dlx1a/dlx2a) locus, and, I56i and I56ii in the Dlx5/Dlx6 (zebrafish dlx5a/dlx6a) locus. Here, we first show that unlike the other three enhancers, mouse I56ii CRE targets a group of GABAergic projection neurons expressing striatal markers Meis2 and Islet1. Meis2 and Islet1 proteins can activate reporter gene transcription via the I56ii CRE, suggesting that they may be potential upstream regulators of Dlx genes in vivo. To determine whether there exists a dlx-mediated regulatory pathway during zebrafish GABAergic neuron formation, we establish two independent lines of transgenic fish in which the GFP reporter gene is controlled by a 1.4kb dlx5a/dlx6a intergenic sequence (encompassing zebrafish I56i and I56ii) and a 1.1kb fragment containing only I56i CRE, respectively. Our observations reveal that dlx5a/dlx6a regulatory elements exhibit a fairly specific activity in the zebrafish forebrain and may be essential for GABAergic neuron generation, while I56i and I56ii are likely to play distinct roles in modulating this process in different subpopulations of cells. Disruption of dlx1a/dlx2a or dlx5a/dlx6a function leads to a marked decrease of enhancer activity in the diencephalon and midbrain as well as a comparatively lesser extent of reduction in the telencephalon. In order to define the specific contribution of various individual CREs to overall Dlx regulation, we also generate a mutant mouse model in which I12b CRE is selectively deleted. Despite that mice homozygous for I12b loss develop normally and harbor no overt morphological defects in the forebrain, targeted deletion of this enhancer results in a significant reduction of Dlx1/Dlx2 transcript levels and seemingly perturbs cell proliferation in the subpallial telencephalon, particularly in the ventricular and subventricular zones of ganglionic eminences. Taken together, these data illustrate a complex and dynamic Dlx regulation in the early developing forebrain through the implications of multiple Dlx CREs with overlapping and diverse functions.

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