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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.
221

Devenir environnemental des antidépresseurs dans les rejets urbains par chromatographie liquide à haute performance couplée à la spectrométrie de masse en tandem

Lajeunesse, André 06 1900 (has links)
Les troubles reliés à la dépression, l’épuisement professionnel et l’anxiété sont de plus en plus répandus dans notre société moderne. La consommation croissante d’antidépresseurs dans les différents pays du monde est responsable de la récente détection de résidus à l’état de traces dans les rejets urbains municipaux. Ainsi, ces substances dites « émergentes » qui possèdent une activité pharmacologique destinée à la régulation de certains neurotransmetteurs dans le cerveau suscitent maintenant de nombreuses inquiétudes de la part de la communauté scientifique. L’objectif principal de ce projet de doctorat a été de mieux comprendre le devenir de plusieurs classes d’antidépresseurs présents dans diverses matrices environnementales (i.e. eaux de surfaces, eaux usées, boues de traitement, tissus biologiques) en développant de nouvelles méthodes analytiques fiables capables de les détecter, quantifier et confirmer par chromatographie liquide à haute performance couplée à la spectrométrie de masse en tandem (LC-QqQMS, LC-QqToFMS). Une première étude complétée à la station d’épuration de la ville de Montréal a permis de confirmer la présence de six antidépresseurs et quatre métabolites N-desmethyl dans les affluents (2 - 330 ng L-1). Pour ce traitement primaire (physico-chimique), de faibles taux d’enlèvement (≤ 15%) ont été obtenus. Des concentrations d’antidépresseurs atteignant près de 100 ng L-1 ont également été détectées dans le fleuve St-Laurent à 0.5 km du point de rejet de la station d’épuration. Une seconde étude menée à la même station a permis l’extraction sélective d’antidépresseurs dans trois tissus (i.e. foie, cerveau et filet) de truites mouchetées juvéniles exposées à différentes concentrations d’effluent dilué traité et non-traité à l’ozone. Un certain potentiel de bioaccumulation dans les tissus (0.08-10 ng g-1) a été observé pour les spécimens exposés à l’effluent non-traité (20% v/v) avec distribution majoritaire dans le foie et le cerveau. Une intéressante corrélation a été établie entre les concentrations de trois antidépresseurs dans le cerveau et l’activité d’un biomarqueur d’exposition (i.e. pompe N/K ATPase impliquée dans la régulation de la sérotonine) mesurée à partir de synaptosomes de truites exposées aux effluents. Une investigation de l’efficacité de plusieurs stations d’épuration canadiennes opérant différents types de traitements a permis de constater que les traitements secondaires (biologiques) étaient plus performants que ceux primaires (physico-chimiques) pour enlever les antidépresseurs (taux moyen d’enlèvement : 30%). Les teneurs les plus élevées dans les boues traitées (biosolides) ont été obtenues avec le citalopram (1033 ng g-1), la venlafaxine (833 ng g-1) et l’amitriptyline (78 ng g-1). Des coefficients de sorption expérimentaux (Kd) calculés pour chacun des antidépresseurs ont permis d’estimer une grande sorption des composés sertraline, desméthylsertraline, paroxetine et fluoxetine sur les solides (log Kd > 4). Finalement, un excellent taux d’enlèvement moyen de 88% a été obtenu après ozonation (5 mg L-1) d’un effluent primaire. Toutefois, la caractérisation de nouveaux sous-produits N-oxyde (venlafaxine, desmethylvenlafaxine) par spectrométrie de masse à haute résolution (LC-QqToFMS) dans l’effluent traité à l’ozone a mis en lumière la possibilité de formation de multiples composés polaires de toxicité inconnue. / Mood disorders such as depression, burn-out and anxiety have increased in our modern society. Increasing amounts of antidepressant prescriptions around the world are now suspected to be the main cause of the recent detection of traces of antidepressant residues within urban wastewaters. These so-called “emerging” substances that possess pharmacological activity towards neurotransmitter regulation in the brain have raised serious concerns from the scientific community. The initial goal of the study was to better understand the fate of various classes of antidepressants present in different environmental matrices (e.g. surface waters, wastewaters, treatment sludge, and biological tissues) by developing novel reliable analytical methods that can detect, quantify and confirm antidepressants using high performance liquid chromatography coupled to tandem-mass spectrometry (LC-QqQMS,LC- QqToFMS). A preliminary study completed at the Montreal sewage treatment plant (STP) confirmed the presence of six antidepressants and four N-desmethyl metabolites in raw sewage (2 – 330 ng L-1). For this primary treatment (physico-chemical), low removal rates (≤ 15%) were obtained. Concentrations of antidepressant close to 100 ng L-1 were also detected directly in the St. Lawrence River at 0.5 km of the effluent outfall. A second study conducted at the same STP allowed the selective extraction of antidepressants in three biological tissues (e.g. liver, brain, and filet) dissected from juvenile brook trouts previously exposed to diluted untreated and treated effluents with ozone. Bioaccumulation of antidepressants was readily observed in fish tissues (0.08-10 ng g-1) for the specimens exposed to untreated effluent (20% v/v), with major distribution in liver and brain. During experiments, a significant correlation was established between the concentrations of three antidepressant detected in brain tissues and the activity of a selected biomarker of exposition (e.g. an N/K ATPase pump involved in the serotonin regulation) measured within dissected synaptosomes from trout exposed to effluents. Investigation of estimated treatment removal efficiencies from various Canadian STPs operating different disinfection modes showed that secondary treatments (biological) were more efficient than primary (physico- chemical) to remove antidepressants (mean removal rates : 30%). The highest amounts detected in treated sludge (biosolids) were obtained respectively with citalopram (1033 ng g-1), venlafaxine (833 ng g-1), and amitriptyline (78 ng g-1). Experimental calculated sorption coefficients (Kd) of each antidepressant predicted fairly good sorption capacities for sertraline, desmethylsertraline, paroxetine, and fluoxetine to solid matters (log Kd > 4). Finally, an excellent mean removal rate of 88% was obtained after ozonation (5 mg L-1) of a primary effluent. However, the characterization of new N-oxide side-products (venlafaxine, desmethylvenlafaxine) in ozonized effluent by high-resolution mass spectrometry (LC-QqToFMS) highlighted the possibility of formation of multiple polar compounds with unknown toxicity.
222

Les récepteurs 5-HT4b adoptent différentes conformations ligand-spécifique ayant des propriétés de signalisation et de régulation distinctes

Younes, Stephane Y. 04 1900 (has links)
Les antidépresseurs actuels sont très similaires au niveau de leur mécanisme d’action et sont plus ou moins efficaces. Un des problèmes majeurs est leur long temps de latence à fournir une action thérapeutique dû aux adaptations des sites pré et post synaptiques. Dans un modèle animal, nous avons récemment découvert que l’agoniste RS67333 des récepteurs 5-HT4 était en mesure de produire en trois jours les mêmes effets antidépresseurs qui normalement prennent de deux à trois semaines à apparaître avec les antidépresseurs actuellement disponibles. De plus, nous avons constaté que les effets antidépresseurs de cet agoniste possédaient une résistance à la tolérance. Il y a d’autres agonistes du même récepteur, tel que le prucalopride qui ne produit pas d’effets antidépresseurs comme RS67333. Étant donné que l’efficacité du Prucalopride à stimuler les 5-HT4Rs est similaire sinon plus grande que celle de RS67333, nous avons énoncé l’hypothèse que le récepteur 5-HT4 pourrait adopter différentes conformations actives suite à son activation par différents agonistes. Nous avons ainsi décidé d’explorer les principales réponses fonctionnelles des récepteurs 5-HT4B en observant leurs propriétés de régulation et de signalisation. Nous avons montré que l’isoforme B du récepteur 5-HT4, étant hautement exprimé dans le système limbique, détient une signalisation et une régulation différentes dépendant du ligand activateur. Nos résultats indiquent que chacun des agonistes testés (5-HT, RS67333, ML10302, Zacopride, Prucalopride) modulent distinctivement la production d’AMPc et l’internalisation du récepteur. Les résultats nous ont clairement permis de déterminer que les agonistes possèdent une efficacité et ou puissance différentes les uns par rapport aux autres. De plus, l’ordre d’efficacité des agonistes à moduler la voie de l’AMPc était (Prucalopride > Zacopride = ML10302 = 5-HT > RS67333) et est différente de leur ordre d’efficacité à induire la régulation du récepteur par internalisation (5-HT > Zacopride > Prucalopride > ML10302 = RS67333). Ainsi, nous avons montré que les 5-HT4Rs adoptent des conformations qui sont ligand-spécifiques. Cela implique que la sélectivité fonctionnelle serait un facteur important à considérer dans les mécanismes d’action antidépresseur des agonistes de ce récepteur. / Antidepressants currently available are very similar toward their mechanism of action and are more or less effective. One major problem is their long latency to provide a therapeutic effect due to adaptations of pre and post synaptic locations. In an animal model, we recently discovered that the agonist RS67333 of the 5-HT4 receptors was able to produce in three days the same antidepressant effects that normally take two to three weeks to appear with the currently available antidepressants. In addition, we found that the antidepressant effects of this agonist had a resistance to tolerance. There are others agonists of the same receptor such as prucalopride, which does not produce antidepressant effects as RS67333. Since the effectiveness of prucalopride to stimulate 5-HT4Rs is similar if not greater than RS67333, we stated the hypothesis that the 5-HT4 receptor could adopt different active conformations following its activation by various agonists. We decided to explore the major functional responses of 5-HT4B by observing their regulatory and signaling properties. We showed that the B isoform of the 5-HT4, being highly expressed in the limbic system, has a different signaling and regulation depending on the ligand. Our results indicate that each of the agonists tested (5-HT, RS67333, ML10302, Zacopride, Prucalopride) distinctively modulate cAMP production and receptor internalization. The results have clearly identified that agonists differed in potency and efficacy. Moreover, the order of effectiveness of agonists to modulate the cAMP pathway was (prucalopride> zacopride = 5-HT = ML10302> RS67333) different from their order of effectiveness in inducing receptor regulation by internalization (5-HT> Zacopride> Prucalopride> RS67333 = ML10302). Thus, we have shown that 5-HT4Rs adopt conformations that are ligand-specific. This implies that functional selectivity is an important factor in the mechanisms of antidepressant action of this receptor agonists.
223

Desenvolvimento da fase extratora SPME de poli(pirrol) e avaliação das técnicas SPME/LC e SBSE/LC para análises de antidepressivos em amostras de plasma / Developmento of polypyrrole SPME extraction phase and evaluation of the SPME/LC and SBSE/LC techniques to antidepressants plasma samples analyses

Chaves, Andréa Rodrigues 27 June 2008 (has links)
A depressão em idosos é uma desordem persistente e recorrente, resultado do stress psicossocial ou efeito de doenças fisiológicas, que podem acarretar a desabilidade do indivíduo, aumento dos sintomas das doenças clínicas, na maior utilização dos serviços de saúde e altas taxas de suicídios.A monitorização terapêutica permite a ndividualização do regime de dosagem, assegurando a eficácia clínica e minimizando os efeitos adversos dos fármacos, prescritos na clínica. Os antidepressivos têm sido monitorados, pois, apresentam intervalos terapêuticos bem estabelecidos, ou seja, a maioria dos pacientes, que apresentam concentrações plasmáticas dentro deste intervalo fixo, tem as desordens psiquiátricas mantidas sob controle e efeitos adversos aceitáveis. Os antidepressivos tricíclicos (ADTs): imipramina, amitriptilina, nortriptilina e desipramina, embora eficazes e ainda muito utilizados, apresentam efeitos adversos, não desejáveis. Os antidepressivos, inibidores seletivos da recaptação de serotonina (SSRIs): citalopram, fluoxetina, paroxetina e sertralina, apresentam eficácia clínica comparável aos clássicos ADTs, mas destituídos dos efeitos adversos associados aos mesmos. Os métodos convencionais, empregados no tratamento de amostras biológicas, para análises de antidepressivos por técnicas cromatográficas, têm sido a extração líquido-líquido e extração em fase sólida. A microextração em fase sólida tem sido empregada em diferentes análises em fluidos biológicos, porém essa técnica apresenta certas limitações como, o número limitado de fases extratoras disponíveis no comércio que sejam adequadas para a análise de compostos não iônicos. A avaliação de novas fases extratoras, mais seletivas, estáveis e de baixo custo tem sido requerida para a análise de fármacos. O interesse no uso de poli(pirrol) (PPY), como fase extratora para SPME, está relacionado às diferentes interações dos fármacos (hidrofóbicas, -, com o grupo funcional polar, troca iônica, ácido-base) aos grupos multifuncionais deste polímero. Sua polimerização pode ser alcançada tanto por oxidação química, quanto por eletrodeposição em meio aquoso ou orgânico. O método eletroquímico apresenta algumas vantagens, tais como: o polímero ou mistura de polimeros podem ser revestidos diretamente em um metal, incorporação de diferentes grupos funcionais, entre outras, a polimerização pode ser eletroquimicamente controlada através da voltametria cíclica. Neste trabalho o poli(pirrol) (PPY) foi eletrodepositado em eletrodo de aço inox e empregado para a microextração em fase sólida dos antidepressivos: paroxetina, fluoxetina, mirtazapina, duloxetina, sertralina e citalopram. As variáveis da eletrodeposição, número de ciclos e contra-íon empregado no processo de eletrodeposição foram otimizadas. Assim como as variáveis SPME: tempo, temperatura, pH e volume de amostra, e tempo e solvente de dessorção; almejando maior sensibilidade para o método SPME-PPY/LC UV proposto. A extração sortiva em barra de agitação (SBSE), técnica recente de preparo de amostras, para a pré-concentração de compostos orgânicos presentes em amostras biológicas, baseia-se na extração estática, através do polímero polidimetilsiloxano (PDMS), no qual ocorre a dissolução (sorção) do analito. Neste trabalho, as técnicas SBSE e cromatografia líquida de alta eficiência com detecção UV (SBSE/LC UV) foram avaliadas para a análise simultânea de antidepressivos em amostras de plasma para fins de monitorização terapêutica. As condições cromatográficas de análise, assim como as variáveis SBSE de extração (tempo, temperatura, força iônica, pH da matriz) e tempo de dessorção, foram otimizadas, visando adequada sensibilidade analítica. A validação analítica foi realizada segundo normas da ANVISA, para ambos os métodos propostos, em diferentes concentrações plasmáticas, as quais contemplam o intervalo terapêutico. Segundo os parâmetros de validação avaliados, os métodos SBSE/LCUV e SPMEPPY/LCUV padronizados poderão ser empregados nas análises dos antidepressivos, para fins de monitorização terapêutica. / Depression in the elderly is a persistent and recurrent disorder resulting from psychosocial stress or physiological effect or disease. This condition can lead to disability, cognitive impairment, enhanced symptoms of medical illnesses, increased use of health care services and, increased of suicide rates. Therapeutic monitoring allows individualization of the dose regimen, ensuring clinical effectiveness and minimizing the adverse effects of drugs, prescribed at the clinic. Antidepressants have been monitored because they present well - established therapeutic intervals; in other words, most of the patients present plasmatic concentrations within this fixed range, so that their psychiatric disorders are kept under control and the adverse effects are acceptable. The tricyclic antidepressants (ADTs) imipramine, amitriptyline, nortryptiline, and desipramine, have adverse effects. The selective serotonin reuptake inhibitors (SSRIs) antidepressants citalopram, fluoxetine, paroxetine, and sertraline, are clinically effectiveness as the classic ADTs, but they do not lead to the adverse effects associated to the latter. The conventional methods employed in the treatment of biological samples for analysis of antidepressants by chromatographic techniques have been the liquid-liquid extraction (LLE) and solid phase extraction (SPE) techniques. Solid-phase microextraction (SPME) has been used in various analyses of biological fluids. However, this technique has limitations such as the small number of comemercially available extracting phases that are appropriate for the analysis of non-ionic compounds. Investigation of new extraction phases that are more selective and stable, as well as inexpensive, has been requested for drug analysis. The interest in the use of poly(pirrole) (PPY) as an extraction phase for SPME is related to the different interactions of the drugs (hydrophobic, - , with the polar functional group, ionic exchange and acid-base) with the multifunctional groups on this polymer. The PPY polymerization can be achieved by chemical oxidation or electropolymerization in aqueous solution or organic solvents. The electrochemical method has advantages such as, the polymer or a mixes of polymers can be directly deposited on a metal wire, different functional groups can be incorporated, polymerization can be electrochemically controlled by cyclic voltammetry. In this work poly(pyrrole) was electropolymerized on stainless steel electrodes and employed for the solid phase microextraction of the antidepressants paroxetine, fluoxetine, mirtazapine, duloxetine, sertraline, and citalopram. The electropolymerization variables, the number of cycles and counterion employed in the process were optimized, as well as the SPME variables, time, temperature, pH, sample volume, and desorption solvent; aiming at a better sensibility for the proposed method SPME-PPY/LC-UV. The stir bar sorptive extraction (SBSE), recently established technique for samples preparation, that targets the pre concentration of organic compounds present in biological samples. It is based on static extraction, through the polymeric polydimethylsiloxane (PDMS), where there is analyte dissolution (sorption). In this work, the SBSE technique and liquid chromatography with UV detector (SBSE/LC-UV) were evaluated for the simultaneous determination of antidepressants in plasma samples for therapeutic monitoring purposes. The cromatographic conditions, the SBSE extraction variables (time, temperature, ionic strength and matrix pH), and the dessorption time were optimized for appropriate analytical sensibility. The analytical validation was accomplished according to the norms of ANVISA for both of the proposed methods, in different plasmatic concentrations, which contemplate the therapeutic interval. According to the evaluated validation parameters, the standardized methods SBSE/LC-UV and SPME-PPY/LC-UV can be used in the analyses of antidepressants for therapeutic drug monitoring purposes.
224

Desenvolvimento das barras imunosorventes de agitação e avaliação das técnicas extração sortiva em barra de agitação, microextração em sorvente empacotado e cromatografia líquida para análise de antidepressivos em amostras de plasma / Development of immunosorbent stir bars and evaluation of stir bar sorptive extraction, microextraction by packed sorbent and liquid chromatography for the analysis of antidepressants in plasma samples

Leandro, Fernanda Zampieri 15 December 2010 (has links)
Neste trabalho, os anticorpos policlonais e monoclonais anti-fluoxetina foram produzidos em coelhos e camundongos, respectivamente, por imunização com o conjugado fluoxetina-soroalbumina bovina. Os anticorpos obtidos foram caracterizados em função da especificidade contra o fármaco por ELISA (enzyme linked immunosorbent assay) e posteriormente, purificados por afinidade em coluna fluoxetina-agarose labmade. Os anticorpos purificados foram imobilizados covalentemente na superfície vítrea das barras SBSE (extração sortiva em barra de agitação) labmade. Após a derivatização das barras com 3-aminopropiltrietoxisilano, dois métodos distintos de acoplamento dos anticorpos às barras SBSE foram avaliados: ativação com glutaraldeído e succinilação seguida de ativação via éster N-hidroxisuccinimida (NHS). A funcionalização das barras SBSE foi comprovada através da imobilização de enzima peroxidase (HRP) em lugar do anticorpo e posterior ensaio enzimático com as barras. Várias barras SBSE com diferentes áreas (1,2; 2,4; e 4,0 cm2) foram preparadas, dentre as quais, as com maior área imunosorvente apresentaram maiores taxas de recuperação do fármaco. A avaliação da morfologia da superfície da barra SBSE imunosorvente foi realizada através de Microscopia Eletrônica de Varredura (MEV). As variáveis do processo SBSE de imunoafinidade foram otimizadas para estabelecer o equilíbrio de sorção antígeno-anticorpo em um menor tempo de análise e obtenção de limite de quantificação compatível com o intervalo terapêutico do fármaco. As capacidades adsortivas das barras imunosorventes foram de 1,2 e 8 microgramas por cm2 para anticorpos policlonais e monoclonais, respectivamente. Os imunosorventes desenvolvidos apresentaram reatividade-cruzada apenas com norfluoxetina (metabólito ativo de fluoxetina). As barras imunosorventes foram reutilizadas aproximadamente 30 vezes, sem perda significativa da eficiência das extrações. Baseados nos parâmetros de validação analítica avaliados, os métodos de SBSE/LC-FD de imunoafinidade desenvolvidos são adequados para a determinação de fluoxetina em amostras de plasma de pacientes em terapia com o fármaco, para fins de monitorização terapêutica. Por conseguinte, esses métodos foram aplicados com êxito para análises de amostras de plasma de pacientes idosos em terapia com Prozac®. Neste trabalho, o método MEPS (microextração em sorvente empacotado)/LC-UV também foi desenvolvido e validado para análise simultânea de sertralina, paroxetina, citalopram, fluoxetina e mirtazapina em amostras de plasma para fins de monitorização terapêutica. As variáveis do processo MEPS foram otimizadas (pH e volume da amostra, força iônica, volume dos ciclos aspirar-dispensar e condições de dessorção) para estabelecer o equilíbrio de sorção em menor tempo de análise e obter sensibilidade analítica adequada para a determinação dos antidepressivos no intervalo terapêutico. O método MEPS/LC-UV desenvolvido permitiu integração da dessorção dos analitos e injeção da amostra no sistema cromatográfico (LC-UV) em uma única etapa, usando a microsseringa de extração MEPS. A fase extratora MEPS, M1 (C8/SCX), foi reutilizada mais de 50 vezes com perda mínima da eficiência da extração, comprovando a robustez do material sorvente. Segundo os parâmetros de validação analítica avaliados, o método MEPS/LC-UV desenvolvido é adequado para a determinação de antidepressivos em amostras de plasma para fins de monitorização terapêutica. / In this work, polyclonal and monoclonal anti-fluoxetine antibodies were developed in rabbits and mice by immunization with fluoxetine-bovine albumin conjugate, respectively. The developed antibodies were characterized on the basis of the specificity against the drug by ELISA (enzyme linked immunosorbent assay) and, subsequently they were purified by labmade fluoxetine-agarose affinity column. The purified antibodies were covalently immobilized onto the glass surface of labmade SBSE (stir bar sorptive extraction) bars. After derivatization of the bars with 3-aminopropyltriethoxysilane, two distinct methods were evaluated for the antibodies coupling to the SBSE bars: activation with glutaraldehyde and succinylation activation via ester N-hydroxysuccinimide (NHS). The functionalization of SBSE bars was confirmed by the immobilization of peroxidase (HRP) instead of the antibody and, subsequent enzymatic assay with the bars. Several SBSE bars with different areas (1.2, 2.4, and 4.0 cm2) were prepared, among of them the largest immunosorbent area showed higher recovery rates of the drug. The evaluation of surface morphology of the SBSE immunosorbent bar was performed using scanning electron microscopy (SEM). The SBSE immunoaffinity variables were optimized to establish sorption equilibrium of antigen-antibody in a short time analysis and to obtain the limit of quantification compatible with the therapeutic range of the drug. The adsorptive capacities of the immunosorbent bars were 1.2 and 8 micrograms per cm2 for polyclonal and monoclonal antibodies, respectively. The developed immunosorbents showed cross-reactivity only with norfluoxetine (active metabolite of fluoxetine). The immunosorbent bars were reused approximately 30 times without significant loss of the extraction efficiency. Based on evaluated analytical validation parameters, the developed immunoaffinity SBSE/LC-FD methods are suitable for the determination of fluoxetine in plasma samples from patients on therapy with the antidepressant for therapeutic drug monitoring. Therefore, these methods were successfully applied for the analysis of plasma samples from elderly patients undergoing therapy with Prozac®. In this work, the method MEPS (microextraction by packed sorbent)/ LC-UV was also developed and validated for the simultaneous analysis of sertraline, paroxetine, citalopram, fluoxetine and mirtazapine in plasma samples for therapeutic drug monitoring. The MEPS process variables were optimized (pH, sample volume, ionic strength, draw-eject cycles volume and desorption conditions) to establish the sorption equilibrium in a short time analysis and to obtain adequate analytical sensitivity for determination of antidepressants within therapeutic range. The developed MEPS/LC-UV method allowed integration of the analytes desorption and sample injection in the chromatographic system (LC-UV) in a single step, using a MEPS extraction microsyringe. The MEPS extraction phase, M1 (C8/SCX) was reused over 50 times with minimum loss of extraction efficiency, proving the robustness of the sorbent material. According to the evaluated analytical validation parameters, the developed MEPS/LC-UV method is suitable for the determination of antidepressants in plasma samples for therapeutic drug monitoring.
225

Vécu de la stigmatisation des femmes atteintes de dépression majeure au Québec : une étude qualitative

Durr, Joanne 04 1900 (has links)
No description available.
226

Pharmakologische und situationsbedingte Beeinflussung der schlafabhängigen Gedächtniskonsolidierung

Görke, Monique 04 September 2013 (has links)
Eine Reihe von Studien konnte zeigen, dass sich Schlaf förderlich auf den Prozess der Gedächtniskonsolidierung auswirkt. Dabei wurde die Konsolidierung unterschiedlicher Lerninhalte mit bestimmten Schlafstadien – z. B. perzeptiv-prozedurale Inhalte mit dem REM (von engl. rapid eye movement) Schlaf – in Verbindung gebracht. Da viele Antidepressiva den REM Schlaf teilweise oder sogar vollständig unterdrücken, stand die Frage im Raum, ob bzw. unter welchen Umständen deren Einnahme die Gedächtniskonsolidierung im Schlaf beeinträchtigen kann. In diesem Zusammenhang scheint zudem die Rolle von Schlafstörungen interessant, da der REM Schlaf im Falle einer Schlafstörung auch Bedeutung für die schlafabhängige Gedächtniskonsolidierung deklarativer Inhalte erlangen kann. Die Arbeit basiert auf einer klinischen Studie (EudraCT 2007-003546-14), in deren Rahmen 32 männliche Probanden im Alter von 18 bis 39 Jahren jeweils über eine Zeitspanne von 48 Stunden im Schlaflabor untersucht wurden. Sie umfasst drei Manuskripte. Im ersten Manuskript wird gezeigt, dass die Einnahme eines REM Schlaf-reduzierenden Antidepressivums (Amitriptylin) die REM Schlaf abhängige perzeptiv-prozedurale Gedächtniskonsolidierung im Schlaf beeinträchtigt, während sie auf die Konsolidierung REM Schlaf unabhängiger Inhalte keinen Effekt hat. Eine weitere unerwünschte Arzneimittelwirkung von Amitriptylin wird im Manuskript 2 beschrieben: Amitriptylin kann den Schlaf stören, indem es das Auftreten periodischer Gliedmaßenbewegungen im Schlaf verstärkt. Im dritten Manuskript wird dargestellt, dass eine neue, fremde Schlafumgebung den Schlaf beeinträchtigen und sich eine solche Beeinträchtigung ähnlich wie eine chronische Schlafstörung auf die schlafabhängige Gedächtniskonsolidierung auswirken kann. Die Ergebnisse werden in den Manuskripten ausführlich diskutiert und im Epilog zusammengefasst sowie in Zusammenhang gesetzt. / Numerous studies suggest that sleep benefits memory consolidation and that the consolidation of different types of memory is differentially influenced by certain sleep stages. For example, consolidation of a perceptual skill is linked with rapid eye movement (REM) sleep whereas declarative memory consolidation is linked with slow wave sleep. Antidepressants strongly suppress REM sleep. Therefore, it is important to determine whether their use can affect memory consolidation. In this context, sleep disturbances are also of interest because when these are experienced REM sleep rather than slow wave sleep seems to become important for sleep-dependent declarative memory consolidation. The work in this thesis is based on a clinical trial (EudraCT 2007-003546-14) in which 32 male subjects (aged 18 through 39 years) were studied in a sleep laboratory over a 48 hour period. Three manuscripts are included. In the first manuscript, it is demonstrated that the REM sleep-suppressing antidepressant amitriptyline specifically impairs REM sleep-dependent perceptual skill learning, but not REM sleep-independent motor skill or declarative learning. In the second manuscript, another adverse effect of amitriptyline is presented: for the first time it is shown that amitriptyline can disturb sleep by inducing or increasing the number of periodic limb movements during sleep. In the third manuscript, it is demonstrated how sleeping in an unfamiliar environment can disturb sleep and how this kind of sleep disturbance can affect memory consolidation during sleep. The results from the specific studies are discussed in detail in the respective manuscripts and are summarized in the epilogue.
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Avaliação das técnicas de microextração e eletroforese capilar em meio não aquoso (NACE) para determinação de antidepressivos em amostras de plasma para fins de monitorização terapêutica / Evaluation of microextractions techniques and nonaqueous capillary electrophoresis (NACE) for the determination of antidepressants in plasma samples for therapeutic drug monitoring

Catai, Ana Paula Formenton 02 March 2012 (has links)
A monitorização terapêutica tem sido descrita como um recurso clínico valioso, na individualização do regime de dosagem, de acordo com a concentração do fármaco em amostras de plasma ou soro. O objetivo da monitorização terapêutica é assegurar a eficácia clínica e minimizar os efeitos adversos dos fármacos prescritos na clínica. A química analítica moderna tem sido direcionada para a simplificação dos métodos através da miniaturização dos sistemas analíticos, minimização do consumo de solvente orgânico e do volume da amostra. Neste contexto, metodologias analíticas utilizando as técnicas de microextração, extração sortiva em barra de agitação (SBSE) e microextração em sorvente empacotado (MEPS), juntamente com a eletroforese capilar em solução não-aquosa (NACE) foram desenvolvidas para fins monitorização terapêutica de antidepressivos inibidores seletivos da recaptação de serotonina (ISRSs: fluoxetina, sertralina, paroxetina e citalopram) em amostras de plasma de pacientes em terapia com ISRSs. Inicialmente foram padronizadas as condições eletroforéticas com detecção espectrofotométrica (UV) para análise simultânea dos ISRSs em amostras de plasma. Dentre as condições avaliadas (diferentes soluções de eletrólitos em meio aquoso e não aquoso, cromatografia eletrocinética micelar e NACE), a técnica NACE-UV foi a única que apresentou resolução dos fármacos adequada. Em seguida, otimizou-se as variáveis inerentes das técnicas de microextração (SBSE e MEPS), visando minimizar o tempo de análise e aumento da sensibilidade analítica. Para o método SBSE/NACE, as variáveis tempo e temperatura de extração, pH da amostra biológica e processo de dessorção foram otimizadas, já para o método MEPS/NACE, as variáveis, pH da amostra biológica, volume da amostra e número dos ciclos aspirar/dispensar foram otimizadas. A validação analítica foi realizada segundo as normas preconizadas pela Agência Nacional de Vigilância Sanitária (ANVISA), com adição de padrão de padrão interno às amostras de plasma enriquecidas com os antidepressivos em diferentes concentrações plasmáticas que contemplam o intervalo terapêutico dos ISRSs. Para avaliar a aplicabilidade das metodologias padronizadas, amostras de plasma de pacientes em terapia com os ISRSs foram analisadas. Os métodos padronizados (SBSE/NACE e MEPS/NACE) foram comparados ao método de referência (LLE/NACE), utilizando a extração líquido-líquido. As técnicas de microextração, quando comparadas à LLE, apresentaram as seguintes vantagens: a reutilização das fases extratoras, procedimentos de extração com reduzido número de etapas, menores volumes de amostras biológicas e de solventes orgânicos. Segundo os parâmetros de validação avaliados, os métodos SBSE/NACE e MEPS/NACE padronizados podem ser empregados nas análises dos antidepressivos (ISRSs) em amostras de plasma, para fins de monitorização terapêutica. / Therapeutic monitoring allows individualization of the dose regimen and has been indicated for the monitoring of well-established therapeutic intervals. In psychiatric disorders, most of the patients require that the plasmatic concentrations to be within a fixed range, so the disorders are kept under control and the adverse effects are acceptable. The aim of the therapeutic monitoring is ensure clinical effectiveness and minimization of adverse effects of drugs prescribed at the clinic. New trends in analytical chemistry have been directed towards simplification and miniaturization of analytical systems, and minimization of organic solvents and sample volume. In this work, analytical methodologies using microextraction techniques, such as stir bar sorptive extraction (SBSE) and microextraction by packed sorbent (MEPS), in conjunction with capillary electrophoresis in a nonaqueous background electrolyte (NACE) were developed for therapeutic drug monitoring of selective serotonin reuptake inhibitors (SSRIs: fluoxetine, sertraline, paroxetine and citalopram) in plasma sample of patients in therapy with SSRIs. First, the optimization of electrophoretic separation of the SSRIs was carried out to obtain simultaneous analysis of all antidepressants. Among the conditions evaluated (different background electrolytes in aqueous and nonaqueous medium, micellar electrokinetic capillary chromatography, and NACE), NACE-UV gave the best results. In the sequence, the optimization of the inherent variables of microextraction techniques (SBSE and MEPS)aiming analyses time minimization and increase of analytical sensibilitywas carried out. For SBSE/NACE methodology development the variables such as time of extraction, temperature of extraction, and matrix pH were optimized. For MEPS/NACE methodology the variables matrix pH and the volume of draw-eject cycles were optimized. Analytical validation was carried out in agreement with the norms of National Health Surveillance Agency (ANVISA) for both of the proposed methods, in different plasmatic concentrations, which completed the therapeutic interval. The developed methods (SBSE/NACE e MEPS/NACE) were compared to the reference method, using liquid-liquid extraction (LLE/NACE). Microextraction techniques, compared to LLE, gave the following advantages: reutilization of the extraction phase, fewer numbers of steps for extraction, reduction of sample volume, and less consumption of organic solvents. According to the evaluated validation parameters, the standardized methods SBSE/NACE and MEPS/NACE can be used in the analyses of antidepressants (SSRIs) in plasma sample for therapeutic drug monitoring purposes.
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Analyse de profils d'expression génique dans des modèles murins d'anxiété/dépression / Gene expression profiles analyses in mouse models of anxiety / depression

Xia, Lin 28 June 2012 (has links)
Dans le cadre de la modélisation des pathologies anxio-dépressives, notre équipe a créé par des approches génétiques et pharmacologiques deux modèles de souris, les souris privées des récepteurs 5-HT1A et 5-HT1B de la sérotonine (5-HT1A/1B-/-) et les souris CORT ayant reçu une exposition chronique de corticostérone exogène (modèle CORT). Ces modèles présentent respectivement un phénotype hyper anxieux et anxio-dépressif. A l’aide de la technique des puces à ADN, nous avons tenté de caractériser le phénotype moléculaire des troubles comportementaux observés dans les différentes régions cérébrales cortico-limbiques de ces modèles et de rechercher les effets des antidépresseurs sur le transcriptome. Nos études ont montré que les états anxio-dépressifs induisent des changements transcriptomiques spécifiques des différentes régions cérébrales du circuit cortico-limbique. Les traitements antidépresseurs ont non seulement inversé ces changements moléculaires, mais également induit des transcriptions génomiques régionales spécifiques. / In the goal of modeling anxio/depressive states, our group has created two mouse models for using different approaches: knockout mice for both 5-HT1A and 5-HT1B receptors (5-HT1A/1B-/-) and stressed mice induced by long-term exposure of exogenous corticosterone (CORT model). These models display a hyper-anxious and an anxio-depressive phenotype, respectively. Using advantage of microarrays, we aimed at characterizing the molecular phenotype in different cortico-limbic brain regions of these mice associated with the behavioral impairments observed in these mice and we investigate the effects of antidepressants on the transcriptome. Our studies showed that anxious/depressive states in mice induced specific transcriptome changes in different brain regions of cortico-limbic circuit. Chronic antidepressant treatment did not only reverse these changes in gene expression, but also induced region-specific genomic transcripts.
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Impact, détection et correction du biais de publication dans la méta-analyse en réseau / Impact, detection and adjustment for reporting bias in network meta-analysis

Trinquart, Ludovic 28 March 2013 (has links)
La méta-analyse (MA) en réseau, en généralisant la MA conventionnelle, permet d'évaluer toutes les comparaisons deux à deux possibles entre interventions. Les biais de publication ont reçu peu d’attention dans ce contexte. Nous avons évalué l’impact des biais de publication en utilisant un réseau de 74 essais randomisés évaluant 12 antidépresseurs contre placebo enregistrés à la FDA et un réseau de 51 essais parmi les 74 dont les résultats étaient publiés. Nous avons montré comment les biais de publication biaisaient les quantités d'effet estimées et le classement des traitements. L'effet du biais de publication peut différer entre MA en réseau et MA conventionnelle en ce que les biais affectant un traitement peuvent affecter le classement de tous les traitements. Nous avons ensuite généralisé un test de détection des biais à la MA en réseau. Il est basé sur la comparaison entre les nombres attendu et observé d’essais avec résultats statistiquement significatifs sur l’ensemble du réseau. Nous avons montré par des études de simulation que le test proposé avait une puissance correcte après ajustement sur l’erreur de type I, excepté lorsque la variance inter-essais était élevée. Par ailleurs, le test indiquait un signal significatif de biais sur le réseau d’essais d’antidépresseurs publiés. Enfin, nous avons introduit deux modèles d’analyse de sensibilité des résultats d'une MA en réseau aux biais de publication: un modèle de méta-régression qui relie la quantité d’effet estimée à son erreur standard, et un modèle de sélection dans lequel on estime la propension d’un essai à être publié puis l’on redresse le poids des essais en fonction de cette propension. Nous les avons appliqués aux réseaux d’essais d’antidépresseurs. Ce test et ces modèles d'ajustement tirent leur force de tous les essais du réseau, sous l’hypothèse qu'un biais moyen commun opère sur toutes les branches du réseau. / Network meta-analysis (NMA), a generalization of conventional MA, allows for assessing all possible pairwise comparisons between multiple treatments. Reporting bias, a major threat to the validity of MA, has received little attention in the context of NMA. We assessed the impact of reporting bias empirically using data from 74 FDA-registered placebo-controlled trials of 12 antidepressants and their 51 matching publications. We showed how reporting bias biased NMA-based estimates of treatments efficacy and modified ranking. The effect of reporting bias in NMAs may differ from that in classical meta-analyses in that reporting bias affecting only one drug may affect the ranking of all drugs. Then, we extended a test to detect reporting bias in network of trials. It compares the number of expected trials with statistically significant results to the observed number of trials with significant p-values across the network. We showed through simulation studies that the test was fairly powerful after adjustment for size, except when between-trial variance was substantial. Besides, it showed evidence of bias in the network of published antidepressant trials. Finally, we introduced two methods of sensitivity analysis for reporting bias in NMA: a meta-regression model that allows the effect size to depend on its standard error and a selection model that estimates the propensity of trial results being published and in which trials with lower propensity are weighted up in the NMA model. We illustrated their use on the antidepressant datasets. The proposed test and adjustment models borrow strength from all trials across the network, under the assumption that conventional MAs in the network share a common mean bias mechanism.
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Padronização e validação do método extração sortiva em barra de agitação e cromatografia líquida de alta eficiência (SBSE/HPLC) para a determinação de antidepressivos em amostras de plasma / Standardization and validation of the stir-bar sorptive-extraction and high-performance liquid chromatography (SBSE/HPLC) method for antidepressant determination in plasma samples

Silva, Silvana Maciel 13 April 2007 (has links)
A monitorização terapêutica permite a individualização do regime de dosagem, assegurando a eficácia clínica e minimizando os efeitos adversos dos fármacos, prescritos na clínica. Os antidepressivos têm sido monitorados, pois, apresentam intervalos terapêuticos bem estabelecidos, ou seja, a maioria dos pacientes, que apresentam concentrações plasmáticas dentro deste intervalo fixo, tem as desordens psiquiátricas mantidas sob controle e efeitos adversos aceitáveis. Os antidepressivos tricíclicos (ADTs): imipramina, amitriptilina, nortriptilina e desipramina, embora eficazes e ainda muito utilizados, apresentam efeitos adversos, não desejáveis. Os antidepressivos, inibidores seletivos da recaptação de serotonina (ISRSs): citalopram e sertralina, apresentam eficácia clínica comparável aos clássicos ADTs, mas destituídos dos efeitos adversos associados aos mesmos. Os métodos convencionais, empregados no tratamento de amostras biológicas, para análises de antidepressivos por técnicas cromatográficas, têm sido a extração líquido-líquido e extração em fase sólida. A extração sortiva em barra de agitação (SBSE), técnica recente de preparo de amostras para a préconcentração de compostos orgânicos presentes em amostras biológicas, baseiase na extração estática, através do polímero polidimetilsiloxano (PDMS), no qual ocorre a dissolução (sorção, partição) do analito. Neste trabalho, as técnicas SBSE e cromatografia líquida de alta eficiência foram avaliadas para a análise simultânea dos antidepressivos em amostras de plasma para fins de monitorização terapêutica. As condições cromatográficas de análise, assim como as variáveis SBSE de extração (tempo, temperatura, força iônica, pH da matriz) e tempo de dessorção, foram otimizadas, visando adequada sensibilidade analítica. A validação analítica foi realizada segundo normas da ANVISA, em diferentes concentrações plasmáticas, as quais contemplam o intervalo terapêutico. O método SBSE/HPLC padronizado apresentou linearidade na faixa de concentração plasmática de 20 a 1000 ng mL-1, precisão interensaio com coeficientes de variação menor que 14% e recuperação relativa de 83 a 110%. Segundo a validação analítica, a metodologia SBSE/HPLC apresentou linearidade, alta sensibilidade, seletividade e precisão analítica adequadas para a análise dos antidepressivos: imipramina, amitriptilina, nortriptilina, desipramina, citalopram e sertralina, em amostra de plasma, para fins de monitorização terapêutica. / Therapeutic drug monitoring allows individualization of drug dosage assuring its clinical efficacy and at the same time minimizing adverse effects of the drugs prescribed in clinics. The antidepressants have been monitored since they present a very well established therapeutic interval. In this sense, most of the patients whose plasmatic concentrations are ranged at that interval present psychiatric disorders under control and drug adverse effects at bearable levels. Despite tricyclic antidepressants (TCAs) such as imipramine, amitriptyline, nortriptyline and desipramine are highly efficient and widely used, they also present undesirable adverse effects. The antidepressants: citalopram and sertraline, which are selective serotonin reuptake inhibitors (SSRIs), present clinical efficacy comparable to the classic TACs, but with no adverse effects associated to the last ones. Liquid-liquid extraction (LLE) and solid phase extraction (SPE) have been usually employed in biological sample pre-treatment for chromatographic analysis. A new technique named sorptive stir bar extraction (SBSE) for sample pre-concentration of organic compounds from biological samples was recently proposed. This technique is based on static extraction through the polymer polidimetilsiloxane (PDMS), in which analyte sorption occurs. In this work, SBSE and HPLC techniques have been evaluated for out antidepressants simultaneous analysis in plasma samples for therapeutic drug monitoring. The chromatographic conditions of analysis, as well as SBSE parameters (time, temperature, ionic strength, matrix pH, desorption time) have been optimized in order to obtain best analytical sensitivity. Analytical validation was carried out according to the norms established by ANVISA, in different plasmatic concentrations, which represent the therapeutic interval. The SBSE/HPLC method developed showed linearity in a concentration plasmatic ranging from 20 to 1000 ng mL-1, inter assay precision with coefficient of the variation lower than 14%, and relative recovery from 83 a 110%. Based on analytical validation, the SBSE/HPLC methodology showed good linearity, high sensitivity, selectivity and suitable repeatability to the analyzed antidepressants: imipramine, amitriptyline, nortriptyline, desipramine, citalopram and sertraline in plasma samples for therapeutic drug monitoring.

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