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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.
1

Riluzole–Triazole Hybrids as Novel Chemical Probes for Neuroprotection in Amyotrophic Lateral Sclerosis

Sweeney, J.B., Rattray, Marcus, Pugh, V., Powell, L.A. 30 May 2018 (has links)
Yes / Despite intense attention from biomedical and chemical researchers, there are few approved treatments for amyotrophic lateral sclerosis (ALS), with only riluzole (Rilutek) and edaravone (Radicava) currently available to patients. Moreover, the mechanistic basis of the activity of these drugs is currently not well-defined, limiting the ability to design new medicines for ALS. This Letter describes the synthesis of triazole-containing riluzole analogues, and their testing in a novel neuroprotective assay. Seven compounds were identified as having neuroprotective activity, with two compounds having similar activity to riluzole.
2

Alga marinha vermelha Gracilaria cornea: novas perspectivas biotecnolÃgicas e implicaÃÃes neurofarmacolÃgicas / Red seaweed Gracilaria cornea: new biotechnological perspectives and neuropharmacological implications

Ricardo Basto Souza 05 March 2015 (has links)
CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / The red seaweed Gracilaria cornea is presented as a natural source still little explored, with potential bioactive, such as sulfated polysaccharides. Its sulfated polysaccharide, agaran-type (AS-Gc), wherein its structure and has anti-inflammatory and anti-nociceptive activity reported in the literature. However, methodological evaluations in their extraction process as well as new potential biological activities are still little reported in the literature. Thus, this study aimed to analyze a new reagent for isolation of AS-Gc and then evaluate its effects and possible mechanisms of action on valuation models psychotropic activity and neuroprotective in vivo and in vitro. Initially, we evaluated the method for isolating sulfated polysaccharides from algae G. cornea using isoamyl alcohol (IAA), in relation to the classical method using 1-hexadecylpyridinium chloride (CPC), considering qualitative and quantitative parameters (percentage yield analysis, physical-chemical and structural characterization) and evaluation of anticoagulant activity in vitro. For analysis of psychotropic effects of AS-Gc, we evaluated the acute administration of three doses (0.3, 3 or 30 mg / kg) and two routes of administration (per os-p.o. or subcutaneous-s.c.) in mice. Then, animals were assessed in physiological and neurobehavioural tests indicative of action level on nervous system and locomotive disorders and behaviors associated with anxiety, depression and sedation. To investigate the potential neuroprotective, we carried out the Parkinson's disease model in rats induced by intrastriatal injection of the neurotoxin 6-hydroxydopamine (6-OHDA), followed by a single dose of ASGC (15, 30 or 60 μg) via intrastriatal. After 14 days, locomotives, neurobehavioral and physiological analyzes were performed. After euthanasia, brain areas (hippocampus, the prefrontal cortex and striatum) were dissected and used to neurochemical and transcriptional analyzes. Additionally, we evaluated the antioxidant potential of AS-Gc in in vivo and in vitro. The results suggest that the classical method using CCP has greater efficiency and quality to obtain a AS-Gc, in relation to the use of AIA. However, the alternative method, using AIA showed potential biotechnological applications to obtain other molecules of commercial and scientific interest. AS-Gc (30 mg / kg, p.o. and s.c.) presented a safety pharmacology and promoted increased exploratory activity in mice. AS-Gc (60 μg, intraestrital) promoted a neuroprotective activity in vivo and in vitro through mitochondrial protection, reduced glutathione induction, lipid peroxidation and nitrite levels reduction, and modulation of transcriptional pathways in the striatum of rats and returning locomotive and renal activities to normal conditions. Thus, this study show new perspectives for biotechnological obtaining chemically different molecules seaweed and suggests new neuropharmacological implications for the use of sulfated agaran from G. cornea. Furthermore, the AS-Gc present therapeutic potential against neurodegenerative disorders. / A alga marinha vermelha Gracilaria cornea apresenta-se como uma fonte natural ainda pouco explorada, com bioativos em potencial, como os polissacarÃdeos sulfatados. Seu polissacarÃdeo sulfatado, do tipo agarana (AS-Gc), possui sua estrutura caracterizada e atividade anti-inflamatÃria e anti-nociceptiva reportada na literatura. Entretanto, avaliaÃÃes metodolÃgicas no seu processo de extraÃÃo, bem como novas atividades biolÃgicas em potencial ainda sÃo pouco reportadas na literatura. Deste modo, o presente estudo objetivou analisar um novo reagente para o isolamento de AS-Gc e, posteriormente, avaliar seus efeitos e possÃveis mecanismos de aÃÃo em modelos de avaliaÃÃo de atividades psicotrÃpicas e neuroprotetoras in vivo e in vitro. Inicialmente, realizou-se uma avaliaÃÃo da metodologia de isolamento de polissacarÃdeos sulfatados isolados da alga G. cornea utilizando Ãlcool isoamÃlico (AIA), em relaÃÃo ao mÃtodo clÃssico utilizando cloreto de 1-hexadecilpiridinio (CCP), considerando parÃmetros qualitativos e quantitativos (anÃlises de percentual de rendimento, de caracterizaÃÃo fÃsico-quÃmica e estrutural) e de uma avaliaÃÃo de atividade anticoagulante in vitro. Para anÃlise de efeitos psicotrÃpicos de AS-Gc, avaliou-se a administraÃÃo aguda de trÃs doses (0,3; 3 ou 30 mg/Kg) e duas vias de administraÃÃo (oral-v.o. ou subcutÃnea-s.c.) em camundongos. Em seguida, os animais foram submetidos a avaliaÃÃo fisiolÃgica e a ensaios neurocomportamentais, indicativo de nÃvel de aÃÃo no sistema nervoso e relacionados a alteraÃÃes locomotoras e de comportamentos associados de ansiedade, depressÃo e sedaÃÃo. Para a investigaÃÃo do potencial neuroprotetor, realizou-se o modelo de induÃÃo de doenÃa de Parkinson em ratos com injeÃÃo intraestriatal da neurotoxina 6-hidroxidopamina (6-OHDA), seguido por Ãnica administraÃÃo de AS-Gc (15, 30 ou 60 Âg), via intraestriatal. ApÃs 14 dias, os animais foram submetidos a anÃlises locomotoras, neurocomportamentais e fisiolÃgicas. ApÃs eutanÃsia, Ãreas cerebrais (hipocampo, cÃrtex prÃ-frontal e corpos estriados) foram dissecadas e utilizadas para anÃlises neuroquÃmicas e transcricionais. Adicionalmente, avaliou-se o potencial antioxidante de AS-Gc em ensaios in vivo e in vitro. Os resultados sugerem que o mÃtodo clÃssico, utilizando CCP, apresenta maior eficiÃncia e qualidade para obtenÃÃo de AS-Gc, em relaÃÃo ao uso de AIA. Entretanto, o mÃtodo alternativo, utilizando AIA, demonstrou potenciais aplicaÃÃes biotecnolÃgicas para obtenÃÃo de outras molÃculas de interesse comercial e cientÃfico. AS-Gc (30 mg/kg, v.o. e s.c.) apresentou uma seguranÃa farmacolÃgica e promoveu o aumento da atividade exploratÃria em camundongos. AS-Gc (60 Âg, intraestrital) promoveu uma atividade neuroprotetora in vivo e in vitro, atravÃs de proteÃÃo mitocondrial, induÃÃo de glutationa reduzida, reduÃÃo dos nÃveis de peroxidaÃÃo lipÃdica e de nitrito, e modulaÃÃo de vias transcricionais em corpo estriado de ratos, retornando atividades locomotoras e renais a condiÃÃes normais. Desta forma, o presente estudo apresenta novas perspectivas biotecnolÃgicas para obtenÃÃo de molÃculas quimicamente diferentes de algas marinhas e sugere novas implicaÃÃes neurofarmacolÃgicas para o uso da agarana sulfatada de G. cornea. Adicionalmente, AS-Gc apresenta potencial terapÃutico contra desordens neurodegenerativas.

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