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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.
251

Retenção do óleo de pequi em micropartículas de concentrado protéico de soro de leite e maltodextrina / Retention of pequi oil in microparticules of whey protein

Matta, Lucidarce Martins da 25 February 2013 (has links)
Submitted by Jaqueline Silva (jtas29@gmail.com) on 2014-12-12T19:37:04Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação-Lucidarce Martins da Matta-2013.pdf: 1987813 bytes, checksum: e8a399f287dfd24a6150990ec96a859d (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2014-12-16T09:24:05Z (GMT) No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação-Lucidarce Martins da Matta-2013.pdf: 1987813 bytes, checksum: e8a399f287dfd24a6150990ec96a859d (MD5) / Made available in DSpace on 2014-12-16T09:24:05Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação-Lucidarce Martins da Matta-2013.pdf: 1987813 bytes, checksum: e8a399f287dfd24a6150990ec96a859d (MD5) Previous issue date: 2013-02-25 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The main objective this bstudy was microencapsulate pequi oil in whey protein concentrate (WPC) and maltodextrin by spray drying, studying the variables of microencapsulation process and subsequently to evaluate the stability of the microcapsules pequi oil by sorption isotherms, glass transition temperature and thermal stability. The study of the production process of microcapsules in pequi oil maltodextrin DE4-7 and WPC by atomization were conducted using a design central composite rotational complete. The independent variables were atomization pressure (2.6 - 5.5 bar) and inlet temperature (136-165 ° C) and the responses were mean diameter, yield and encapsulation efficiency. Microcapsules intended for the stability study were produced following process conditions: inlet temperature 170 °C, 4 bar atomizing pressure, compressed air flow, air drying and feeding, 2.4 m3.h-1 270 m3. h-1 and 120.0 mL.h-1, respectively. The sorption isotherms were determined by generating isotherms at temperatures of 20 °C, 30 °C and 40 °C, the glass transition temperature was measured by DSC and thermal stability by TG. Pequi oil used had monounsaturated fatty acid profile, with over 50% oleic acid, and thermal stability at temperatures of maximum 225 °C. Increasing the inlet temperature led to increased encapsulation efficiency and reduction in process yield. The microcapsules have spherical shape and their surfaces showed no pores and tooth, has similar capacity to absorb water at temperatures evaluated, being different between 0.4 <Aw <0.6. The GAB model was the best set for the isotherms obtained at temperatures of 20 ° C and 30 ° C, while at 40 ° C adjusted to better model Oswin. The transition temperatures of the microcapsules Ton = -22.5 ° C and Toff = -2.5 ° C. The microcapsule pequi oil has thermal stability up to 180 ° C / O objetivo deste trabalho foi microencapsular o óleo de pequi em concentrado protéico de soro de leite e maltodextrina utilizando a técnica de atomização ou “spray drying”, estudando as variáveis de processo de microencapsulação envolvidas na técnica e, posteriormente, avaliar a estabilidade das microcápsulas de óleo de pequi produzidas na condição otimizada determinada no estudo de processo de microencapsulação pelas isotermas de sorção, transição vítrea e estabilidade térmica. O estudo do processo de produção de microcápsulas de óleo de pequi em maltodextrina dextrose equivalente 4-7 e concentrado protéico de soro de leite por atomização foi realizado utilizando o delineamento composto central rotacional completo. As variáveis independentes foram a pressão de atomização (2,6 – 5,5 bar) e a temperatura de entrada (136 – 165 °C) e as respostas o diâmetro médio, o rendimento e a eficiência de encapsulação. As isotermas de sorção foram determinadas por gerador de isotermas nas temperaturas de 20°C, 30 °C e 40 °C; a temperatura transição vítrea foi medida por Calorimetria Diferencial Exploratória e a estabilidade térmica por Termogravimetria. O óleo de pequi utilizado apresentou perfil de ácidos graxo monoinsaturados, sendo que apresentava mais de 50% de ácido oléico e estabilidade térmica a temperaturas máximas de 220 °C. O estresse fotoxidativo aplicada na avaliação da estabilidade do óleo de pequi produziu processos oxidativos de modo que houve degradação de β-caroteno e produção de peróxidos e aldeídos, produtos do processo oxidativo lipídica. O óleo de pequi exposto diretamente ao estresse apresentou redução da entalpia de cristalização em comparação ao branco, sugerindo que a calorimetria diferencial exploratória pode ser uma análise útil para verificação do estagio oxidativos de produtos lipídicos. O aumento da temperatura de entrada conduziu ao aumento da eficiência de encapsulação e redução no rendimento de processo. As microcápsulas apresentaram formatos e superfícies, respectivamente, esféricos e com enrugamentos e ausência de poros; exibiram semelhantes capacidades de adsorverem água nas temperaturas avaliadas, sendo diferentes entre o intervalo 0,4 < Aw <0,6 onde essa capacidade foi maior com o aumento da temperatura. O modelo GAB foi o que melhor ajustou-se para as isotermas obtidas nas temperaturas de 20 °C e 30 °C, enquanto, em 40 °C melhor ajustou-se o modelo de Oswin. As temperaturas de transição vítrea das microcápsulas Ton =-22,5 °C e Toff=-2,5 °C. A microcápsula de óleo de pequi possui estabilidade térmica até 180°C.
252

Desenvolvimento e caracterização de sistemas multiparticualdos de liberação prolongada para o antiinflamatório cetoprofeno / Development and characterization of systems multiparticualdos of extended release for the anti-inflammatory ketoprofen

OLIVEIRA, Rodinelli Borges de 08 February 2010 (has links)
Made available in DSpace on 2014-07-29T15:29:05Z (GMT). No. of bitstreams: 1 Tese Rodinelli resumo.pdf: 19418 bytes, checksum: 1be52e77b9ebe222b50b13d4efcfa7a5 (MD5) Previous issue date: 2010-02-08 / Ketoprofen is a nonsteroid anti-inflammatory drug (NSAID) which is used in rheumatic disorders and in mild to moderate pain. Ketoprofen has a short biological half life and the commercially available conventional release formulations require dosages to be administered at least 2-3 times a day. Due to these characteristics, ketoprofen is a good candidate for the preparation of controlled release formulations. In this work, a multiparticulate sustained release dosage form containing ketoprofen in a carnauba wax matrix was developed. Particles were prepared by emulsion congealing technique, spray drying, fluidized bed and conventional granulation. Hydroxypropylmethylcellulose (HPMC) and carnauba wax were used in the formulations as the main ingredients to promote sustained release. Particles were evaluated for their rheological properties, morphology and drug release characteristics. For the emulsion congealing technique, system variables were optimized using fractional factorial and response surface experimental design in order to obtain spherical particles with high drug load and sustained drug release profile. The optimized particles had an average diameter of approximately 200 &#956;m, 50% (w/w) drug load, good flow properties and a prolonged release profile (up to 24 hours) for ketoprofen. Particles prepared with HPMC 2208 by spray drying, fluidized bed and conventional granulation did not exhibit prolonged release of the ketoprofen after the dispersion of the drug dosage for in the dissolution medium. Due to their good flowability and capability in prolonging ketoprofen release, carnauba wax pellets prepared by emulsion congealing were submitted to permeation studies through Wistar rats intestinal segments. Results demonstrated that carnauba wax microparticles were able to promote continuous and sustained ketoprofen release, leading to high apparent permeability coefficient in the upper small intestine. Carnauba wax microspheres prepared in this work represent a new multiparticulate sustained release system for the NSAID ketoprofen, exhibiting good potential for application in further pharmaceutical processes. In addition, the microspheres can be prepared without incorporating the drug and used as an excipient in direct compression processes. / O cetoprofeno é um antiinflamatório não-esteróide usado em doenças reumáticas e dores leves a moderadas. Apresenta meia-vida curta e as formulações convencionais de liberação imediata são administradas de 2 a 3 vezes ao dia. Essas características de farmacocinética e posologia, além do aparecimento de efeitos colaterais relacionados à administração de altas doses do fármaco, diminuem o seu uso clínico. O presente trabalho propõe o desenvolvimento de sistemas multiparticulados de liberação prolongada para o antiinflamatório cetoprofeno. As partículas foram preparadas pela técnica de emulsão congelante, spray drying, leito fluidizado e granulação convencional. Nas formulações foram utilizados hidroxipropilmetilcelulose e cera de carnaúba como os principais agentes promotores de liberação prolongada. As partículas foram avaliadas principalmente quanto às suas propriedades reológicas, morfologia e perfil de dissolução do fármaco. A otimização da técnica de emulsão congelante permitiu a preparação de partículas esféricas de cera de carnaúba com carga do cetoprofeno em torno de 50 %, diâmetro próximo de 200 &#956;m e liberação do fármaco de forma contínua por período maior do que 24 h. As partículas constituídas por hidroxipropilmetilcelulose (HPMC) 2208, preparadas pelas técnicas de spray drying, leito fluidizado e granulação convencional, não resultaram em liberação prolongada após a dispersão da forma farmacêutica em meio de dissolução, como ocorre para as partículas de cera de carnaúba preparadas por emulsão congelante. Os pellets de cera de carnaúba, por apresentarem melhores propriedades de fluxo, alta dispersibilidade e liberação contínua e prolongada, foram utilizados para estudo de permeação em diferentes segmentos intestinais de ratos Wistar. Este estudo demonstrou que as partículas de cera de carnaúba disponibilizaram o cetoprofeno de forma lenta e gradual e proporcionaram alto coeficiente de permeabilidade aparente no intestino delgado superior. Em virtude das suas propriedades, os pellets de cera de carnaúba preparados no presente trabalho podem ser perfeitamente utilizados nos processos farmacêuticos e representam um novo sistema multiparticulado para a liberação prolongada do fármaco cetoprofeno. Além disso, as partículas podem ser preparadas sem a incorporação do fármaco e utilizadas como excipiente nos processos de compressão direta.
253

Preparação e caracterização in vitro de micropartículas de heparina fracionada potencialmente aplicáveis ao tratamento da trombose venosa profunda / Preparation and in vitro characterization of microparticles containing fractionated heparin potentially applicable to treatment of deep vein thrombosis.

Samantha Sant'Anna Marotta de Oliveira 28 April 2009 (has links)
A trombose venosa profunda (TVP) é uma patologia grave de alta incidência mundial. Quando não diagnosticada precocemente e tratada adequadamente pode evoluir causando sérias complicações, como a embolia pulmonar e insuficiência venosa crônica, as quais são responsáveis por altas taxas de morbidade e mortalidade. Seu tratamento utiliza terapia com anticoagulantes pelas vias parenteral e oral (para manutenção) que estão associadas a prejuízos bem documentados limitando seu uso, além de resultar em baixa adesão do paciente ao tratamento. Os sistemas de liberação modificada de fármacos, tais como as micropartículas poliméricas, representam uma grande área em desenvolvimento, a qual tem recebido atenção de pesquisadores e indústrias de todo o mundo e recebido investimentos crescentes nas últimas três décadas. As micropartículas poliméricas possuem grande estabilidade, capacidade industrial e possibilitam ajustes para alcançar o perfil de liberação adequado e/ou o direcionamento para determinado sítio de ação. O estudo teve início com o desenvolvimento e validação do método analítico para a quantificação da enoxaparina sódica. A turbidimetria foi a técnica de escolha, pois os resultados utilizando CLAE não foram satisfatórios. Este estudo teve como objetivo a obtenção e caracterização físico-química de um sistema de liberação microparticulado para veiculação de uma heparina fracionada (HF), a enoxaparina sódica, muito utilizada no tratamento da TVP, visando um aumento da biodisponibilidade do fármaco com controle da sua biodistribuição. As micropartículas contendo a enoxaparina sódica foram preparadas utilizando o copolímero dos ácidos lático e glicólico (50:50) (PLGA), biodegradável, através do método da dupla emulsificação/ evaporação do solvente. As partículas obtidas foram caracterizadas pela técnica de microscopia eletrônica de varredura (MEV) e apresentaram forma esférica com superfície lisa e regular. As análises do tamanho e distribuição dos tamanhos de partícula foram realizadas por dispersão de luz laser e apresentaram perfil monomodal para a maioria das formulações. O perfil de liberação in vitro do fármaco encapsulado foi avaliado por 35 dias e apresentou cinética de liberação de pseudo ordem zero, modelo de Higuchi (1961), indicando que a difusão foi o principal mecanismo de liberação. A velocidade de degradação das micropartículas é, através da difusão do fármaco, um parâmetro muito importante e determinante da liberação in vivo. / Deep vein thrombosis (DVT) is a severe disease with high incidence worldwide. When it is not early diagnosed and properly treated it can develop and to cause serious complications, such as pulmonary embolism and chronic venous insufficiency, which are responsible for high morbidity and mortality rates. The treatment of DVT is accomplished with parenteral and oral (for maintenance) anticoagulants. They are associated to damage well documented that limit their use resulting in poor adherence of patients to treatment. Drug delivery systems, such as polymeric microparticles, represent a significant development area. It has received attention of researchers and industries around the world and increased investments in last three decades. The polymeric microparticles have great stability, industrial capacity and they allow adjustments to achieve the suitable release profile and / or direction for a particular site of action. The study started with development and validation from the analytical method to quantification of enoxaparin sodium. Turbidimetric technique was used because the results by HPLC were not satisfactory. The aim of this work was the preparation and physical-chemical characterization of a microparticle release system for delivery of a fractionated heparin (FH), enoxaparin sodium, widely used to the treatment of DVT to increase the drug bioavailability and control their biodistribution. The microparticles containing enoxaparin sodium were prepared from a biodegradable polymer poly (lactic-co-glycolic acid) (50:50) (PLGA) using double emulsification / evaporation of the solvent method. The particles obtained were characterized by scanning electron microscopy technique (SEM) and showed spherical shape with smooth and regular surface. The analysis of the size and distribution of particle sizes were performed by scattering of laser light and showed unimodal profile for the most of formulations. In vitro drug release profile from the microparticles was evaluated in 35 days showing pseudo zero order kinetics, Higuchi model (1961). This indicated that main mechanism of drug release was diffusion.
254

Avaliação de formulações de uso tópico a base de insulina no distúrbio das glândulas lacrimais e na regeneração da córnea em ratos diabéticos / Evaluation of topical formulations based insulin disorder of lacrimal glands and in the regeneration of the cornea in diabetic rats

Estael Luzia Coelho Madeira da Cruz 18 July 2014 (has links)
Distúrbios na superfície da córnea e nas glândulas lacrimais acometem com frequência os indivíduos com diabetes mellitus. Atualmente não existe tratamento seguro e eficaz para feridas na córnea e o tratamento da síndrome do olho seco (SOS) é predominantemente sintomático. A administração tópica da insulina (INS) é uma estratégia promissora para tratar esses distúrbios, devido à presença de seus receptores na superfície ocular e na glândula lacrimal, e aos seus efeitos metabólicos e mitogênicos. No entanto, os fármacos aplicados topicamente na forma de solução são rapidamente drenados do olho, resultando em uma baixa biodisponibilidade local. O objetivo deste trabalho foi desenvolver formulações contendo INS e avaliar a sua influência no distúrbio das glândulas lacrimais e na regeneração da córnea em ratos diabéticos. Foram desenvolvidas quatro formulações contendo 1 UI/mL de INS: dispersão contendo insulina (DISP INS), dispersão contendo micropartículas quitosana/INS (DISP MP INS), gel termorreversível in situ com INS (Gel INS) e Gel contendo as micropartículas quitosana/INS (Gel MP INS). Também foram produzidas formulações \"brancas\", sem a veiculação do fármaco: dispersão contendo micropartículas sem insulina (DISP MP s/INS); gel termorreversível in situ sem insulina (Gel s/INS). As MP incorporadas nas formulações foram preparadas por spray drying e apresentaram tamanho de 4,0±0,1 ?m, morfologia adequada e grande quantidade de INS (77±6%). Todas as formulações apresentaram pH e osmolalidade compatíveis com o uso ocular. Durante o estudo in vivo, foi realizado o tratamento diário (15 dias) dos animais diabéticos, com as formulações (50 ?L) em ambos os olhos, exceto nos controles positivo (sem diabetes) e controle negativo (diabético não tratado). Todos os animais tratados com INS aumentaram a produção de fluido lacrimal, sendo que, ao término do tratamento, não foi observada diferença estatística entre o controle positivo e aqueles tratados com DISP INS e com Gel MP INS. A INS foi detectada na glândula lacrimal e no globo ocular dos animais tratados com DISP MP INS, Gel INS e Gel MP INS, sendo que a maior concentração de INS foi encontrada nos ratos tratados com Gel MP INS. Ao término do tratamento houve redução da glicemia dos animais tratados com a INS, o que pode sugerir um tratamento coadjuvante em pacientes diabéticos. Estudos de citologia de impressão mostraram que o Gel INS e Gel MP INS foram capazes de aumentar o número de células do epitélio da córnea e melhorar a relação núcleo/citoplasma em relação ao controle negativo. A histologia do globo ocular mostrou que essas duas formulações também melhoraram a espessura do epitélio da córnea, que foi semelhante a dos controles positivos. Conclui-se que a incorporação da INS nos géis e nas micropartículas desenvolvidas desempenhou um efeito positivo no tratamento da síndrome do olho seco e de lesões na córnea. / Disorders in the corneal surface and the lachrymal glands often affect individuals with diabetes mellitus. Nowadays there is no safe and effective treatment for wounds in the cornea and the treatment of dry eye syndrome (DES) is primarily symptomatic. Topical administration of insulin (INS) is a promising strategy for treating these disorders due to the presence of receptors on the ocular surface and lacrimal gland, besides its metabolic and mitogenic effects. However, the drugs applied topically in the form of a solution are quickly drained from the eye, resulting in a low local bioavailability. The aim of this study was to develop formulations containing INS and evaluate their influence on disorders of lacrimal glands and cornea healing in diabetic rats. Four formulations containing 1 IU/mL of INS were developed: dispersion containing insulin (DISP INS), dispersion containing chitosan microparticles/INS (DISP MP INS), in situ forming gel containing INS (Gel INS) and in situ forming gel containing microparticles chitosan/INS (Gel MP INS). \"White\" formulations were also produced without the drug: dispersion containing microparticles without insulin and in situ forming gel without insulin. MP incorporated in the formulations were prepared by spray drying and showed size of 4.0±0.1 ?m, proper morphology and high INS load (77±6%). All formulations exhibited pH and osmolarity compatible with the ocular use. In vivo studies were performed using diabetic rats that were treated daily (15 days) with instillation of the formulations (50 ?L) in both eyes, except in the positive controls (health rats) and negative control (untreated diabetic rats). All animals treated with INS showed an increase in the production of tear fluid. After treatment, no statistical difference was observed between the positive control and those treated with DISP INS and Gel MP INS. The INS was detected in the lacrimal gland of the animals treated with DISP MP INS, Gel INS and Gel MP INS, with the highest concentration of INS found in mice treated with Gel MP INS. After treatment there was a reduction in blood glucose of the animals treated with formulations containing INS, which suggests that developed formulations may be used as an adjuvant treatment in diabetic patients. Impression cytology studies showed that the Gel INS and Gel MP INS were able to increase the number of the corneal epithelium cells and improve nucleus/cytoplasm ratio compared to the negative control. The histology of the eyeball showed that these two formulations have improved the thickness of the corneal epithelium, which was similar to the positive controls. In conclusion, incorporation of INS in the gels and MP developed induced a positive effect in the treatment of dry eye syndrome and corneal wound.
255

Influência de micro e nanopartículas lipídicas sólidas na eficácia de formulações fotoprotetoras bioativas / Influence of solid lipid micro and nanoparticles on the efficacy of bioactive photoprotective formulations

Rodrigo Molina Martins 22 April 2014 (has links)
O presente trabalho teve o objetivo de desenvolver uma formulação tópica contendo os filtros solares benzofenona-3 e avobenzona microencapsulados em associação com filtro solar não encapsulado octocrileno e nanoparticulas lipídicas sólidas contendo rutina (formulação completa) e avaliar a eficácia fotoquimiopreventiva dessa formulação usando biópsias de pele humana e pele reconstruída in vitro. Microparticulas lipídicas sólidas contendo grandes quantidades de filtros solares, benzofenona-3 e avobenzona foram obtidas pela técnica do spray congealing com propriedades adequadas para aplicação tópica. Além disso, o processo de microencapsulação foi capaz de diminuir a penetração de benzofenona-3 na pele, aumentar a estabilidade da avobenzona frente à radiação ultravioleta A e a capacidade fotoprotetora desses filtros microencapsulados em formulações tópicas quando expostos a radiação ultravioleta. Nanopartículas lipídicas sólidas contendo o flavonóide rutina foram produzidas pelo processo de homogeneização a alta pressão e suas condições foram otimizadas pelo método da desejabilidade rendendo nanopartículas lipídicas sólidas com tamanho médio de 74,22 ±2,77 nm, índice de polispersividade de 0,161±0,03 e eficiência de encapsulação de 98,90 ±0,25 %. Em adição, as nanopartículas mostraram serem capazes de proteger a viabilidade celular de fibroblastos de ratos L929 irradiados com radiação ultravioleta A e B. Para a eficácia fotoquimiopreventiva a formulação completa foi capaz de evitar/diminuir a formação de células apoptóticas, caspase-3, dímeros de ciclobutanodipirimidina, metaloproteinases e peroxidação lipídica em pele humana e pele reconstruída expostos a UVB. O processo tecnológico de microencapsulação e nanoencapsulação dos ativos avaliados mostrou ser eficaz, não comprometendo as propriedades de fotoproteção dos filtros solares e rutina, apresentando resultados similares ou melhores do que as formulações contendo os ativos na forma livre. Portanto, o desenvolvimento de formulações contendo ativos microencapsulados e nanoencapsulados é uma alternativa interessante para o emprego em produtos comerciais para proteção solar, por diminuir as características indesejáveis como penetração e instabilidade, melhorando as propriedades fotoprotetoras e evitando a necessidade de desenvolver novos compostos com propriedades fotoprotetoras. / This study aimed the pharmaceutical development of a topical formulation containing an association of microencapsulated sunscreens benzophenone-3 and avobenzone, free sunscreen octocrylene and rutin flavonol solid lipid nanoparticles (complete formulation). This formulation was assessed for photochemoprotective ability using human skin obtained surgically and reconstructed human skin. Solid lipid microparticles containing large amounts of sunscreens benzophenone-3 and avobenzone were obtained by the spray congealing technique under conditions that allowed the manufacture of microparticles with suitable properties for topical application. The microencapsulation conditions were also able to reduce the penetration of benzophenone-3 through the skin, enhanced the stability of avobenzone against the ultraviolet radiation (UVR) and increased the photoprotective ability of both filters in topical formulations exposed to UVR. Solid lipid nanoparticles containing rutin were produced by the high pressure homogenization process whose conditions were optimized using the desirability method, yielding nanoparticles with size of 74.22 ± 2.77 nm, polispersivity index of 0.161 ± 0.03 and encapsulation efficiency of 98.90 ± 0.25%. In addition, the nanoparticles were able to avoid the death of L929 mice fibroblasts exposed to UVR A and B. For the photochemopreventive ability studies, the complete formulation was able to reduce/avoid the induction of apoptotic cells, caspase-3, CPDs, metalloproteinases and lipid peroxides in human skin obtained surgically and reconstructed human skin in vitro exposed to UVB.Thus, the micro and nanoencapsulation solved some intrinsic problems related to sunscreens and rutin without, however, compromising their photohemoprotective ability, since the results showed similar or better efficacy when compared to the formulations containing actives in free form. Therefore, the development of formulations containing microencapsulated and nanoencapsulated compounds is an interesting alternative for employment in commercial products for sun protection by decreasing the undesirable characteristics, such as penetration and instability, improving the photoprotective properties and avoiding the need to develop new compounds with photoprotective characteristics.
256

Analyse quantitative et qualitative sur puce de vésicules extracellulaires en milieux complexes au sein d'une plateforme nanobioanalytique / On-chip analysis and nanometrology of blood microparticles with label-free detection and characterization techniques

Obeid, Sameh 11 May 2017 (has links)
Les vésicules extracellulaires (VEs) sont des nanovésicules circulantes (30 à 100nm de diamètre) libérées dans l'espace extracellulaire par la plupart des cellules humaines, suite à leur activation ou à leur apoptose. Les VEs se divisent en 3 grandes catégories ; les exosomes (Exo), les microparticules (MPs) et les corps apoptotiques (cAPO). Les VEs sont présentes à l'état physiologique dans les différents fluides biologiques du corps humain et jouent un rôle majeur dans différents processus physio-pathologiques. De nos jours, plusieurs techniques, certaines en routine, sont utilisées pour étudier les VEs. Cependant, aucune d'entre elles ne permet de déterminer à la fois leur concentration, leur taille et leurs caractéristiques biochimiques. Un consensus existe sur la nécessité de combiner des techniques pour disposer enfin d'une caractérisation fine et complète des VEs. Il est d'un intérêt majeur de développer des plateformes analytiques dédiées à ces VEs en vue d'améliorer la qualification des échantillons biologiques et de découvrir de nouveaux biomarqueurs de pathologies humaines ou de bio-indicateurs de suivi thérapeutique.Notre projet consiste à développer une plateforme NanoBioAnalytique (NBA) combinant trois techniques : l'imagerie par Résonance des Plasmons de Surface (SPRi), la Microscopie à Force Atomique (AFM) et la Spectrométrie de Masse (MS). L'enjeu est de développer une interface biopuce-instruments qui permettra d'effectuer des investigations multiphysiques et multiéchelles apportant, en une stratégie globale, les informations plus complètes sur les différentes populations de VEs.[...]Ces travaux ont montré la capacité de notre plateforme à détecter sélectivement, et simultanément, différentes sous-populations des VEs co-existantes dans un échantillon complexe tel que du plasma, en s'appuyant sur l'expression différentielle des marqueurs protéiques membranaires. Les taux de capture se sont avérés être directement corrélés à la concentration des vésicules dans l'échantillon injecté. L'analyse AFM a permis de déterminer la distribution en taille de différentes sous-populations de VEs et permettre une analyse différentielle de la distribution en taille sur la gamme 20 nm - 1000 nm. Enfin, des études protéomiques "sur-puce" ont été également engagées afin de caractériser la composition en protéines des VEs libérées sous différentes conditions. Cette analyse a permis d'établir des premiers profils protéomiques différentiels des VEs dans les échantillons étudiés.La plateforme NBA est une méthode efficace pour caractériser et quantifier les VEs, sans marquage et avec une grande sensibilité, sur une large gamme dynamique (environ 10(7) à 10(12) particules/mL) cohérente avec celle existante en fluide physiologique et sur une plage de taille couvrant 2 décades. Elle s'inscrit parmi les approches les plus prometteuses pour l'investigation des VEs en complément de la cytométrie en flux. La grande adaptabilité de cette méthode d'analyse des VEs ouvre de larges perspectives de déploiement dans les secteurs de la Santé, de l'Environnement et de l'Agro-alimentaire. / Extracellular vesicles (EVs) are small vesicles (30 to 1000 nm) released from different cell types, upon activation or apoptosis, and present in most body fluids (Blood, Urine….). Based on the current state of knowledge of their biogenesis and biochemical properties, EVs can be devided into three distinct populations: exosomes (EXO), microparticles (MPs) and apoptotic bodies (APOb). EVs have been found to play important biological roles and are also biomarkers of different pathologies. […] The first step consists of the injection of the samples containing EVs onto the biochip surface. This step is accomplished by SPR technique that allows label-free monitoring of EVs immunocapture onto the surface of a biochip presenting different specific bioreceptors. Following the capture of EVs, a nanometrological investigation of the biochip surface by AFM is engaged to characterize the physical properties of captured vesicles (size, morphology, etc..). Owning a nanometrical resolution, AFM can discriminate between individual EVs and vesicles or protein aggregates, leading to an accurate characterization of individual vesicles. The coupling of SPR technique with AFM was adapted to offer a representative global view of each array of bioreceptors and to measure the size of thousands of individual EVs. A proteomic investigation was also engaged to characterize the proteomic compositions of the different subpopulations of EVs. Such an investigation could contribute to the understanding of EVs biogenesis, biology and pathophysiology. To evaluate the potential of our platform to detect, quantify and characterize nanoparticles, two calibration particles, which cover the lower and upper size range of EVs, were chosen: (i) virus-like particles of 50 nm of diameter, also called CP50, and (ii) protein-functionnalized synthetic beads of 920 nm of diameter, called CP920. The capture tests in SPR showed a specific capture of these two calibration particles with their specific bioreceptors, immobilized onto the biochip surface, regardless the complexity of the media in which they were diluted. Also, a positive correlation was obtained between the capture level, measured by SPR, and the particle 9
257

Encapsulation de protéines dans des systèmes polymériques particulaires par des procédés sans solvants toxiques pour l'ingénierie tissulaire du cartilage / Protein encapsulation into polymeric particulate systems using non-toxic solvents for cartilage tissue engineering

Swed, Amin 10 July 2015 (has links)
Ce travail a été mené afin de développer des systèmes polymériques particulaires chargés en facteur de croissance (TGF-β1) en vue d’une application à l’ingénierie tissulaire du cartilage. Tout d’abord, des nanoparticules d’acide poly(lactique-co-glycolique) (PLGA) ont été générées par un procédé basé sur la séparation de phase. De plus, des microparticules de PLGA ont été formées à l’aide d’un procédé d’émulsification/extraction du solvant en milieu CO2 pressurisé. L’un des avantages de ces procédés de formulation est l’utilisation de solvants injectables, non toxiques et non volatils. Les systèmes polymériques préparés ont été caractérisés et des particules sphériques à libération contrôlée ont été obtenues avec un rendement d’encapsulation satisfaisant tout en préservant l’activité biologique du facteur de croissance. Les particules chargées en TGF-β1 ont ensuite été incorporées dans un hydrogel injectable à base d’un dérivé cellulosique silanisé (Si-HPMC) contenant des cellules souches. Le biomatériau obtenu a été caractérisé en termes de morphologie, de propriétés rhéologiques et pour sa capacité à libérer le facteur de croissance. La libération contrôlée et localisée du TGF-β1 pourrait induire la survie, la prolifération ainsi que la différenciation chondrocytaire des cellules souches associées ce qui contribuerait à la régénération du cartilage. En conclusion, le biomatériau hybride élaboré au cours de ce travail possède un potentiel prometteur pour l’ingénierie tissulaire du cartilage. / The aim of this work is to develop polymeric particulate systems loaded with transforming growth factor (TGF-β1) for cartilage tissue engineering application. First, nanoparticles of PLGA (poly(lactic-co-glycolic) acid) were generated using a phase separation method while PLGA microparticles were prepared by an emulsification/extraction process in CO2 medium. Interestingly, non-toxic, non-volatile injectable solvents were used in the formulation processes. The prepared polymeric systems were characterized; spherical particles with sustained release were obtained and satisfactory encapsulation efficiency was achieved with preservation of the growth factor bioactivity. TGF-β1-loaded particles were then incorporated within injectable silanized cellulose-based hydrogel (Si-HPMC) containing stem cells. The obtained biomaterial was characterized in terms of morphology, rheological properties and release study. The local and sustained release of TGF-β1 could induce survival, proliferation and differentiation of stem cells into chondrocytes which may promote cartilage regeneration. To conclude, the elaborated hybrid biomaterial has a promising potential for cartilage tissue engineering.
258

Der CytoBead-Assay – Eine neue Möglichkeit der multiparametrischen Autoantikörperanalytik bei systemischen Autoimmunerkrankungen

Sowa, Mandy, Großmann, Kai, Scholz, Juliane, Röber, Nadja, Rödiger, Stefan, Schierack, Peter, Conrad, Karsten, Roggenbuck, Dirk, Hiemann, Rico 18 June 2020 (has links)
Bei Verdacht auf Vorliegen einer systemischen Autoimmunerkrankung wird für die serologische Routinediagnostik ein Zwei-Stufen-Verfahren empfohlen. Zuerst werden Autoantikörpern (AAK) mittels sensitiver zellbasierter indirekter Immunfluoreszenz (IIF)-Teste bestimmt. Ein positives Ergebnis muss aufgrund der Möglichkeit von falsch-positiven Ergebnissen mit einem weiteren, spezifischen Test bestätigt werden. Dieses sukzessive Vorgehen ist notwendig, da zurzeit keine Assaytechnik die notwendigen Anforderungen an ein einstufiges Verfahren hinsichtlich Sensitivität und Spezifität erfüllt. Im Sinne einer effektiven AAK-Diagnostik kann heute schon eine simultane Bestimmung von mehreren AAK mittels multiparametrischer Bestätigungstests die Diagnosefindung im Vergleich zu konventionellen, monoparametrischen Tests wesentlich verkürzen. Jedoch erlauben die verfügbaren multiparametrischen AAK-Nachweismethoden nicht die Kombination von Screening- und Bestätigungstesten. Deshalb wurde basierend auf der digitalen Fluoreszenz mit der hier vorgestellten CytoBead Technologie ein neuer Ansatz entwickelt. Ziel war die Kombination der empfohlenen Stufendiagnostik bestehend aus sensitivem Screening und spezifischer Bestätigungsdiagnostik in einer Reaktionsumgebung und darüber hinaus die Möglichkeit der Adaption auf die serologische Diagnostik mehrerer Autoimmunerkrankungen. Durch a) die Nutzung von Standardglasobjektträgern, b) die Kombination von nativen zellulären oder Gewebesubstraten mit antigenbeladenen fluoreszierenden Mikropartikeln (Beads) in einer Reaktionsumgebung, c) die Möglichkeit der manuellen und automatischen Auswertung mittels IIF und d) die Erhebung von quantitativen Fluoreszenzmessergebnissen konnten die Nachteile der bisher bestehenden Testsysteme überwunden werden. Das neue Prinzip ist auf verschiedene multiparametrische AAK-Nachweise wie zum Beispiel die Bestimmung von antinukleären Antikörpern und AAK gegen entsprechende nukleäre und zytoplasmatische autoantigene Zielstrukturen anwendbar. Damit wurde weiterhin die Basis für die simultane AAK-Multiparameterbestimmung für die Serologie der Zöliakie und von ANCA-assoziierten systemischen Vaskulitiden geschaffen.
259

Metabolic Mechanisms in Physiologic and Pathologic Oxygen Sensing

Stephens, Olivia R. 28 August 2019 (has links)
No description available.
260

Analýza DNA izolované z probiotických výrobků s využitím magnetických mikročástic / Analysis of DNA isolated from probiotic products using magnetic microparticles

Oliva, Jan January 2015 (has links)
This thesis is interested in isolation and identification of probiotic bacteria in three different probiotic products using polymerase chain reaction (PCR). DNA in quality suitable for PCR was isolated from crude lysates using three different types of magnetic microparticles and phenol extraction. Identification genera and species of probiotic bacteria was proven using genus and species specific PCRs. Results were in accordance with data presented by manufacturers.

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