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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.
411

Nanopartículas de PLA e PLA-PEG contendo tamoxifeno: preparação, caracterização e avaliação in vitro e in vivo / PLA and PLA-PEG nanoparticles containing tamoxifeno: preparation, characterization and in vitro and in vivo evaluation

Oliveira, Samantha Sant'Anna Marotta de 22 July 2014 (has links)
O câncer de mama constitui o segundo tipo de câncer mais frequente no mundo e o mais comum entre as mulheres, representando uma das principais causas de morte. O tamoxifeno é um fármaco antiestrogênico utilizado para o tratamento deste tipo de câncer desde 1971 e ainda é o mais utilizado nos casos de tumores mamários que expressam receptores de estrógeno. Apesar de apresentar resultados significativamente positivos, seu efeito antiestrogênico não se restringe apenas ao sítio tumoral causando, com isso, efeitos colaterais graves que podem deixar sequelas. A proposta deste trabalho foi desenvolver sistemas de liberação nanoparticulados à base de PLA e PLA-PEG para veiculação do tamoxifeno, como uma estratégia para o potencial aumento da segurança e da eficácia deste fármaco através de um possível direcionamento passivo ao sítio de ação, devido à permeabilidade vascular aumentada destas regiões tumorais. As nanopartículas foram preparadas pela técnica de nanoprecipitação e apresentaram diâmetro médio inferior a 200 nm para a maioria das formulações. Foram avaliados três estabilizantes, o poloxamer 407, o poloxamer 188 e o polissorbato 80, este último proporcionou maior eficiência de encapsulação, 86,7% e 100%, nas nanopartículas de PLA e PLA-PEG, respectivamente. Quanto à composição das nanopartículas de PLA-PEG, o polímero utilizado inicialmente (PLA(1000)-PEG(750)) apresentou distribuição de tamanho heterogênea, perfil multimodal e alto índice de polidispersividade. Assim, este polímero foi substituído pelo PLA(5000)-PEG(1000), que apresentou distribuição de tamanho uniforme, perfil monomodal e baixo índice de polidispersividade. A caracterização por microscopia eletrônica de varredura comprovou a homogeneidade no tamanho de partícula, mostrando seu formato esférico. As análises de espectrofotometria no infravermelho e calorimetria diferencial exploratória sugeriram que não ocorreu nenhum tipo de interação ou reação entre o fármaco e os demais componentes das formulações. Dois métodos analíticos para a determinação do tamoxifeno foram validados com sucesso por CLAE e espectroscopia UV-vis. O perfil de liberação in vitro do tamoxifeno a partir das nanopartículas de PLA apresentou característica sustentada e alcançou 50% em 180 h, tendo sido totalmente liberado após 288 h. Já as nanopartículas de PLA(5000)-PEG(1000) liberaram apenas 16,9% do fármaco após 216 h. A liberação do fármaco a partir das nanopartículas foi muito mais lenta comparada ao tamoxifeno não encapsulado, evidenciando a vantagem da incorporação do fármaco em nanopartículas compostas por PLA e PLA-PEG. No estudo do perfil de concentração plasmática em ratas Wistar, não foi possível detectar o fármaco e seu principal metabólito pelo método por CLAE desenvolvido, sugerindo que os sistemas nanoparticulados tenham extravasado rapidamente para os órgãos. / Breast cancer is the second most frequent type of cancer in the world and it is the most common among women, representing a major cause of death. Tamoxifen is an antiestrogen drug used in the treatment of this type of cancer since 1971 and it is the most employed drug in the treatment of breast cancer subtypes that expresses estrogen receptors. Despite presenting significantly positive results, its antiestrogen effect is not restricted to the tumour site, causing, as consequence, severe side effects. The purpose of this work was to develop nanostructured drug delivery systems based on PLA and PLA-PEG loaded with tamoxifen, as a strategy to potentially increase the safety and efficacy of this drug through a possible passive accumulation the site of action, due to the enhanced vascular permeability of tumour sites. Nanoparticles were prepared by the nanoprecipitation technique and presented average diameter smaller than 200 nm for the majority of the formulations. Three stabilizing adjuvants were analysed, poloxamer 407, poloxamer 188 and polysorbate 80 and the last one yielded the highest encapsulation efficiency, 86.7% and 100%, for the PLA and PLA-PEG nanoparticles, respectively. Regarding the PLA-PEG nanoparticles composition, the first polymer employed was (PLA(1000)-PEG(750)), which presented heterogeneous particle size distribution, multimodal profile and high polydispersity index. So, it was replaced by PLA(5000)-PEG(1000), which exhibited uniform particle size distribution, monomodal profile and low polydispersity index. The characterization by scanning electron microscopy confirmed the homogeneity of particles size, evidencing their spherical shape. Infrared spectrophotometry and differential scanning calorimetry analysis suggested that any interaction or reaction had occurred between the drug and the other components of the formulations. Two analytical methods for tamoxifen quantification were successfully validated by HPLC and UV-vis spectroscopy. In vitro tamoxifen release profile from PLA nanoparticles presented sustained release and reached 50% in 180 h, being completely released after 288 h, whereas PLA(5000)-PEG(1000) nanoparticles released only 16.9% of tamoxifen after 216 h. Drug release from nanoparticles was much slower compared to the non-encapsulated tamoxifen, showing the advantage of nanoparticles composed of PLA and PLA-PEG. In the plasmatic concentration profile study carried out in Wistar rats, it was not possible to detect tamoxifen or its main metabolite by the HPLC method, suggesting that nanoparticles quickly extravased to organs.
412

Influência do hospedeiro (CHO) e da estratégia de cultivo nas estruturas glicídicas e propriedades moleculares da tireotrofina humana / INFLUENCE OF THE HOST (CHO) AND OF THE CULTIVATION STRATEGY ON GLYCAN STRUCTURES AND MOLECULAR PROPERTIES OF HUMAN THYROTROPHIN

Oliveira, João Ezequiel de 07 December 2007 (has links)
Neste trabalho foi desenvolvida pela primeira vez uma estratégia de purificação com duas etapas, uma cromatografia de troca iônica e uma cromatografia líquida de alta eficiência em fase-reversa (RP-HPLC), para obter um hTSH derivado de CHO (r-hTSH-IPEN), que mostrou-se rápida e prática, permitindo um rendimento de 70% e uma pureza > 99%. Um aumento de ~60% na produtividade de r-hTSH-IPEN foi observado quando condições de cultura celular foram alteradas de 5% de CO2 para ar (0,03% CO2). A qualidade dos produtos obtidos em ambas as condições foi avaliada com relação à estrutura dos N-glicanos, aos isômeros de carga e à atividade biológica em comparação com a única preparação comercial conhecida (Thyrogen®) e com uma preparação de referência de origem hipofisária (p-hTSH) do National Hormone and Pituitary Program (NIDDK, EUA). Os N-glicanos identificados nas preparações recombinantes foram do tipo complexo, apresentando estruturas bi-, tri- e tetra- antenárias, algumas fucosiladas, sendo 86-88% sialiladas com níveis variáveis. As três estruturas mais abundantes foram monosialiladas, representando ~69% de todas as formas identificadas nas três preparações. A principal diferença foi encontrada em termos de antenaridade, com 8-10% mais estruturas bi-antenárias na ausência de CO2 e 7-9% mais estruturas tri-antenárias na presença de CO2. No caso do p-hTSH foram identificadas estruturas do tipo complexo, com alta-manose e híbridas, a maioria delas contendo resíduos terminais de ácido siálico e/ou sulfato. As duas estruturas mais abundantes contem um ou dois resíduos de sulfato, sendo que no primeiro caso ele inesperadamente se liga a uma galactose. A porcentagem de ligação do ácido siálico à galactose nas conformações 2-3 e 2-6 foi de 68 ± 10% e 32 ± 10% respectivamente. Não foram observadas diferenças fundamentais nos isômeros de carga, nas três preparações recombinantes, os perfis da focalização isoelétrica mostrando seis bandas distintas no intervalo de pI de 5,39 a 7,35. Uma distribuição consideravelmente diferente, com várias formas na região ácida, foi observada, no entanto, para duas preparações hipofisárias. Uma bioatividade ligeiramente superior (p <0,02) foi encontrada para o r-hTSH-IPEN obtido na presença de CO2 quando as preparações foram analisadas com boa precisão por um simples bioensaio em dose única; esta atividade, no entanto, não é significativamente diferente da atividade do Thyrogen, as duas preparações sendo 1,6 e 1,8 vezes mais potentes do que a preparação de referência (p-hTSH). Podemos concluir que, pelo menos para o caso dos r-hTSH derivados de CHO, diferentes condições de cultivo não afetam significativamente as estruturas dos N-glicanos, distribuição de isómeros de carga ou atividade biológica. Thyrogen e r-hTSH-IPEN, quando comparados com p-hTSH-NIDDK, apresentaram cerca de 7% de aumento da massa molecular determinada por MALDI-TOF-MS. Esta técnica, que permite uma avaliação exata da massa do heterodímero, apresentou valores de MR de 29611, 29839 e 27829, respectivamente. Diferenças significativas foram encontradas entre o r-hTSH e o p-hTSH pelo que se refere às propriedades hidrofóbicas, avaliadas por RP-HPLC. Também foram observadas diferenças relacionadas à composição de carboidratos, principalmente de ácido siálico e galactose, tendo sido encontrado um menor teor destes resíduos no p-hTSH. / A novel, fast and practical two-step purification strategy, consisting of a classical ion exchange and a reversed-phase high performance liquid chromatography (RP-HPLC), for rapidly obtaining CHO-derived hTSH, was set up providing r-hTSH with 70% yield and > 99% purity. A consistent increase of ~60% in the secretion yields of r-hTSH-IPEN was observed by changing cell culture CO2 conditions from 5% CO2 to air environment (0.03% CO2). The overall quality of the products obtained under both conditions was evaluated for what concerns N-glycan structure, charge isomers and biological activity in comparison with a well known recombinant biopharmaceutical (Thyrogen®) and with a pituitary reference preparation (p-hTSH) from National Hormone and Pituitary Program (NIDDK, USA). The N-glycans identified in the recombinant preparations were of the complex type, presenting bi-, tri- and tetra-antennary structures, sometimes fucosylated, 86-88% of the identified structures being sialylated at variable levels. The three most abundant structures were monosialylated glycans, representing ~69% of all identified forms in the three preparations. The main difference was found in terms of antennarity, with 8-10% more bi-antennary structures obtained in the absence of CO2 and 7-9% more tri-antennary structures in its presence. In the case of p-hTSH, complex, high-mannose and hybrid N-glycan structures were identified, most of them containing sialic acid and/or sulphate terminal residues. The two most abundant structures were shown to contain one or two sulphate residues, one of which unexpectedly bound to galactose. The sialic acid-galactose linkage was also determined, having found that 68 ± 10% was in the 2,6 and 32 ± 10% in the 2,3 conformation. No remarkable difference in charge isomers was observed between the three recombinant preparations, the isoelectric focusing profiles showing six distinct bands in the 5.39 - 7.35 pI range. A considerably different distribution, with more forms in the acidic region, was observed, however, for two native pituitary preparations. When analyzed via a simple and precise single-dose bioassay, a slightly higher bioactivity (p<0.02) was found for r-hTSH-IPEN obtained in the presence of CO2. This potency however, was not significantly different from that of Thyrogen, the two preparations being 1.6-1.8-fold more potent than the reference preparation of p-hTSH. We can conclude that, at least for the case of CHO-derived r-hTSH, different production processes do not greatly affect its N-glycan structures, charge isomer distribution or biological activity. Thyrogen and r-hTSH-IPEN, when compared to p-hTSH-NIDDK, presented about a 7% increased relative molecular mass (MR) determined by MALDI-TOF-MS analysis. This technique, allowing accurate heterodimer mass determinations, provided MR values of 29611, 29839 and 27829, respectively. Significant differences in hydrophobic properties, evaluated by RP-HPLC, were found for r-hTSH and p-hTSH. Also differences related to carbohydrate moiety, mainly in the amount of sialic acid and galactose, were found for these preparations, a much lower content of these sugar residues being observed in p-hTSH
413

Metodologia otimizada para a determinção de digestibilidade de dietas para camarões marinhos em cultivo / Improved methodology for determination of digestibility in diets for cultured penaeid shrimp

Oliveira, Gabriela Faria 29 April 2008 (has links)
A aqüicultura desenvolveu-se rapidamente nos últimos anos, sendo a carcinicultura um dos segmentos mais lucrativos e crescentes, onde a ração representa o custo mais elevado da produção e a maior fonte de poluição das fazendas de camarão. Nesse contexto, verifica-se a busca por rações de qualidade e novos ingredientes. Assim, o presente trabalho objetivou aperfeiçoar o método in vivo de análise da digestibilidade de rações, desenvolvendo sistemas de cultivo (aquários: 14,3L e tanques: 160L), com recirculação de água marinha e filtro biológico, empregando rações comerciais (fase de crescimento) e dietas experimentais com diferentes produtos da soja (farelo de soja, farelo de soja texturIzado e farelo de soja micronizado) e marcador de óxido crômico (teste de digestibilidade) em camarões da espécie Litopenaeus vannamei. Os sistemas e a manutenção aplicada foram eficientes na conservação da estabilidade dos parâmetros abióticos monitorados (compostos nitrogenados, temperatura, salinidade e pH). Os camarões apresentaram maior ganho de peso (P<0,05) com menores coeficientes de variação nos tanques. Não houve diferenças (P>0,05) entre as dietas testadas (aquários), mas a digestibilidade acompanhou o maior processamento da soja (tanques). Os resultados sugerem a maior adequabilidade dos tanques para testes nutricionais. / Aquaculture have developed quickly in the last years, being the shrimp culture the more profitable and increasing sector. Feed comprise the highest variable costs of production and a major pollution source from shrimp farms. Hence is the search for quality feeds and new ingredients. Thus, the present work aimed to improve the in vivo method of feed protein digestibility, developing culture systems (aquariums: 14,3L and tanks: 160L) with seawater recirculation and biological filters. Commercial feeds (growth phase) and experimental diets with different soy products (soybean meal, texturized soybean meal and micronized soybean meal) with chromic oxide as marker (digestibility test) in Litopenaeus vannamei shrimps. Systems and maintenance procedures were efficient in the conservation of abiotic parameters (nitrogen products, temperature, salinity and pH). Shrimps showed higher weight gain (P<0,05) with low variation coefficient in the tanks compared to aquaria. No difference (P>0,05) was observed between the diets tested in the aquaria. But the digestibility was major to higher processed soybean meal (tanks). The results suggest the better adequacy to nutritional tests.
414

Micelas de longo tempo de circulação contendo tamoxifeno como sistema nanocarreador para otimização da terapia do câncer de mama / Long time circulation micelles containing tamoxifen as nanocarrier system for otimization of the breast cancer therapy

Souza, Marina Claro de 10 May 2013 (has links)
O câncer de mama é a segunda principal causa de morte entre as mulheres nos países em desenvolvimento, devido ao seu alto grau de malignidade. O tratamento baseia-se, principalmente, em terapias hormonais, uma vez que as células deste tipo de tumor expressam, em sua maioria, um elevado número de receptores hormonais, responsáveis pela regulação do crescimento do mesmo. O tamoxifeno é um fármaco da classe dos moduladores seletivos de receptores de estrógeno, que atua através do antagonismo à ativação de tais receptores por este hormônio, reduzindo, assim, a taxa de crescimento celular do tecido tumoral. Embora o tratamento com tamoxifeno seja altamente efetivo, este se relaciona a severos efeitos colaterais dosedependentes. O objetivo central deste trabalho foi desenvolver sistemas micelares de longo tempo de circulação contendo tamoxifeno, preparados à base do fosfolipídeo DSPE-PEG(n), associado ou não ao derivado de vitamina E TPGS, para administração intravenosa, capazes de permitir um acúmulo maior do fármaco no sítio tumoral devido a suas dimensões nanométricas, permitindo, desta forma, a redução da dose e a consequente redução dos efeitos colaterais. A determinação da eficiência de encapsulação e a quantificação do tamoxifeno no estudo de liberação in vitro a partir dos sistemas obtidos foram realizadas por CLAE, utilizando métodos previamente validados. Os melhores resultados foram alcançados com as formulações à base de DSPE-PEG(2000) e TPGS, preparadas pelo método de evaporação do solvente, as quais apresentaram diâmetro médio inferior a 20 nm, baixo índice de polidispersividade e eficiência de encapsulação entre 70 e 95%. A análise por microscopia eletrônica de transmissão evidenciou o formato esférico e comprovou a homogeneidade do tamanho das partículas. Os sistemas foram caracterizados, ainda, por espectrofotometria no infravermelho para avaliação de possíveis interações entre os componentes das formulações. O perfil de liberação in vitro demonstrou que após 168 h, no máximo cerca de 30% do fármaco foi liberado, verificando-se que o aumento na quantidade de TPGS na formulação reduziu a porcentagem de tamoxifeno liberado. A baixa taxa de liberação in vitro sugere que a maior parte do fármaco mantenha-se no interior da estrutura micelar durante o período de permanência no sangue, favorecendo a chegada da nanoestrutura íntegra ao sítio tumoral. No estudo do perfil de concentração plasmática em ratas Wistar, não foi possível detectar o fármaco e seu principal metabólito pelo método por CLAE desenvolvido, sugerindo que os sistemas micelares tenham extravasado rapidamente para os órgãos. / Breast cancer is the second main cause of death among women in development countries due to their high malignance grade. The treatment is mainly based on hormonal therapies, once the cells of the majority of mammary tumors express a high number of hormone receptors, responsible for the tumor growth. Tamoxifen is a selective estrogen receptor modulator drug, acting through the antagonism of the activation of the estrogen receptor, reducing thus the tumor growing rate. Despite the treatment with tamoxifen is highly effective, it is related to severe dose-dependent side effects. The central objective of this work was the development of long time circulation micelles containing tamoxifen, prepared with the phospholipid DSPEPEG(n) and TPGS, a vitamin E derivative, by the method of solvent evaporation, for intravenous administration, able to allow a higher accumulation of the drug at the tumoral site due to their nanometric dimensions, leading to a reduction in the dose and consequently in the side effects. The determination of the encapsulation efficiency and the quantification of tamoxifen in the in vitro release profile study from the micellar systems were carried out by HPLC, using methods previously validated. The best results were achieved with the formulations based on DSPE-PEG(2000) and TPGS, which showed mean particle diameter less than 20 nm, low polydispersity index and encapsulation efficiency ranging from 70 to 95%. The transmition electronic microscopy pointed the spherical shape and proved the homogeneity of particle size. The systems were also characterized by infrared spectrophotometry to identify eventual interactions among the components of the formulations. The in vitro release profile study showed that after 168 h, a maximum of about 30% of tamoxifen was released, evidencing that the increase of the TPGS amount in the formulation reduced the amount of tamoxifen released. The low rate of in vitro release drug suggests that the major part of the drug will remain encapsulated during the period of blood permanence, favoring the arrival of the intact nanostructure at the tumoral site. During the evaluation of the plasmatic concentration profile, conducted with Wistar rats, it was not possible to detect neither the tamoxifen nor its main metabolite, suggesting that the intact micelles may have quickly accumulated in the organs.
415

Somatosensory cortical processing in the mouse forepaw system

Zhao, Wen-Jie 14 September 2016 (has links)
Der primäre somatosensorische Kortex (S1) besteht aus sechs Schichten (L1L6).Die koordinierte Aktivität dieser sechs Schichten kortikaler Neurone ist entscheidend für die sensorische Wahrnehmung und die Steuerung willkürlichen Verhaltens. Es ist jedoch noch wenig über die synaptischen Mechanismen bekannt, die die Verarbeitung zwischen den kortikalen Schichten bei sich aktiv verhaltenden Tieren bestimmen. Ich habe einfache und doppelte in vivoGanzzellableitungen im VorderpfotenAreal von S1 in der Maus gemacht, und gezeigt, dass Pyramidalzellen in L2/3 und L5 während einer Bewegung der Vorderpfote Unterschiede in ihren intrinsischen Eigenschaften und der Dynamik ihrer Membranpotenziale zeigen. Doppelableitungen haben gezeigt, dass sensorisch und motorisch ausgelöste synaptische Eingänge zwischen den Zellschichten weitgehend korreliert waren, niederfrequente unterschwellige Potenzialschwankungen und spontane Aktionspotenziale jedoch einen schichtspezifischen Zeitverlauf zeigten. Auf einer längeren Zeitskala beobachteten wir, dass spontane Bewegungen der Vorderpfote eine Dekorrelation unterschwelliger Aktivität zwischen den Schichten auslösten. Des Weiteren zeigten L5Pyramidalzellen durch ihre Aktivität sensorisch ausgelöste und spontane Bewegungen der Vorderpfote stärker an, als L2/3Neurone. Insgesamt deuten meine Daten darauf hin, dass Unterschiede zwischen den Zellschichten beim Timing von Aktionspotenzialen, bei der unterschwelligen Synchronisierung und bei den mittleren Feuerraten sowohl von der Quelle des zu Grunde liegenden synaptischen Eingangs als auch vom resultierenden Verhalten abhängen. Außerdem konnte ich zeigen, dass Neurone im VorderpfotenAreal von S1 auf leichte Kältereizung der Vorderpfote antworten, und dass diese Antwort vom Ionenkanal transient receptor potential cation channel subfamily M member 8 (TRPM8) in primären sensorischen afferenten Neuronen vermittelt wird. / The primary somatosensory cortex (SI) is composed of six layers (L1L6). The coordination of neural activities across six layers of cortical neurons is essential for reliable sensory perception and the control of voluntary behavior. However, the synaptic neural mechanisms governing translaminar cortical processing in behaving animals are still unknown. I made in vivo single and dual whole cell recordings in mouse forepaw SI, my work revealed that L2/3 and L5 pyramidal neurons have distinct intrinsic properties and membrane potential dynamics during forepaw behavior. Dual recordings showed that sensory and movement evoked synaptic inputs were closely correlated across layers, but low frequency subthreshold fluctuations and spontaneous action potentials exhibited a laminar specific temporal profile. At longer time scales, my data showed that spontaneous forepaw movement evoked a decorrelation of subthreshold activity across layers. Furthermore, L5 pyramidal neurons signaled sensory evoked and spontaneous forepaw movements more strangely than L2/3 neurons. Overall, my work suggests that laminar differences in the timing of action potential firing, subthreshold synchrony and mean firing rates are dependent both on the origin of the underlying synaptic input and the behavioral outcome of the event. In addition, I identified that forepaw SI neurons respond to mild cooling stimulation of the forepaw and that this response is mediated by the Transient receptor potential cation channel subfamily M member 8 (TRPM8) in primary sensory afferent neurons.
416

Mastzellen sind entscheident an der Thrombin-induzierten kutanen Entzündungsreaktion beteiligt

Sünder, Cathleen Annett 01 February 2012 (has links)
Zusätzlich zu seiner Funktion innerhalb des Gerinnungssystems vermittelt Thrombin inflammatorische Reaktionen. Mastzellen (MZ) sind durch die Freisetzung von proinflammatorischen Mediatoren wie Maus-Mastzell Proteasen (MCPTs mouse mast cell proteases auch als mMCPs bekannt), Zytokinen und Chemokinen. charakterisiert. Da Thrombinrezeptoren, auch als Proteinase-aktivierbare Rezeptoren (PAR) bekannt, von MZ exprimiert werden, wurde untersucht ob eine MZ-Aktivierung über die Thrombin/PAR Interaktion bei einer dermalen Entzündung eine Rolle spielt. Die intrakutane Injektion von Thrombin in die Ohren von C57BL/6 Kit+/+ Mäusen löste eine sofortige kutane Entzündung, einhergehend mit einer starken Ohrschwellung, aus. Im Vergleich dazu war diese Schwellung in MZ-defizienten C57BL/6 KitW-sh/W-sh Mäusen deutlich stärker, was darauf hindeutet, dass MZ anti-inflammatorisch wirken. Die lokale Rekonstitution von C57BL/6 KitW-sh/W-sh Mäusen mit knochenmarksgenerierten MZ normalisierte diesen Effekt. Die quantitative histomorphometrische Untersuchung der MZ bestätigte zusätzlich eine starke Degranulation der MZ nach Thrombininjektion nach. PCR-Analysen der MZ wiesen die Expression aller bekannten Thrombin-Rezeptoren. Die Stimulation mit verschiedenen Konzentrationen von Thrombin oder PAR-agonistischen Peptiden führte zu einer dosis-abhängigen Degranulation der MZ, was nahe legt, dass die Degranulation der MZ für die Limitierung der thrombin-induzierten Entzündung nötig ist. Gestützt wird die Hypothese durch die Tatsache, dass Zellkulturüberstand von degranulierten MZ zu einer Inaktivierung der Thrombinaktivität führt. Des Weiteren führte die Injektion von Thrombin in die Ohren von MCTP4-defizienten Mäusen zu einer deutlich erhöhten Ohrschwellung im Vergleich zur korrespondierenden Wildtyp-Maus. Zusammengenommen zeigen die Ergebnisse, dass die sofortige thrombin-induzierte Entzündungsreaktion durch kutane MZ kontrolliert wird. Dieser Mechanismus wird teilweise durch MCPT4 vermittelt. / In addition to its function in the coagulation system, thrombin mediates inflammatory reactions. Mast cells (MCs) are characterized by releasing inflammatory mediators like mouse mast cell proteases (MCPTs, also designated mMCPs), cytokines, and chemokines, upon activation. Since thrombin-receptors, also known as Proteinase-activated receptors (PAR), are expressed by MCs, it was questioned whether MC activation via the thrombin/PAR axis plays a role in skin inflammation. Intracutaneous injection of thrombin in ears of C57BL/6 Kit+/+ mice induced immediate inflammatory skin reactions associated with a distinct ear swelling. This swelling was more pronounced in MC-deficient C57BL/6 KitW-sh/W-sh mice, indicating that MCs are anti-inflammatory, local reconstitution of C57BL/6 KitW-sh/W-sh mice with C57BL/6 Kit+/+ bone marrow-derived MCs normalized this effect. Additionally thrombin injection resulted in a strong degranulation of MCs assessed by quantitative histomorphometry. PCR analysis of MCs displayed expression of all known thrombin receptors. Stimulation with thrombin or PAR agonistic peptides resulted in a dose-dependent degranulation of MC, suggesting MC degranulation could be necessary for the limitation of thrombin-induced inflammatory responses. Supporting this hypothesis, supernatant from degranulated MCs inactivated thrombin activity. Furthermore, injection of thrombin in ears of C57BL/6 MCPT4-deficient mice, resulted in markedly increased ear swelling compared to the corresponding wild type mice. Together our results suggest that thrombin-induced immediate inflammatory skin reactions are controlled by cutaneous MCs, a mechanism partly mediated via MCPT4.
417

Vitamin D3-Analogon /Beta-Cyclodextrin-Kavitate- Herstellung,Charackterisierung und In-vitro-Liberation aus Dermatika-

Franke, Patrick 17 April 1998 (has links)
Das Ziel der vorliegenden Arbeit war die Evaluierung der Möglichkeit der Bildung von Einschlußverbindungen eines neuen Vitamin D3 Analogon mit nativem [beta]-Cyclodextrin, Dimethyl-[beta]-Cyclodextrin, [beta]-Cyclodextrin-Polymer, Maltosyl-[beta]-Cyclodextrin, Hydroxypropyl-[beta]-Cyclodextrin und Carboxyethyl-[beta]-Cyclodextrin. Die resultierenden Addukte wurden im Hinblick auf Zusammensetzung und Eigenschaften charakterisiert. Weiterhin wurden in vitro und in vivo Untersuchungen durchgeführt, um den Einfluß von [beta]-Cyclodextrinen, vor allem im Hinblick auf Retardierungseffekte, nach Einarbeitung in Salben für die Indikation Psoriasis zu interpretieren. Die Herstellung der festen Kavitate erfolgte in Abhängigkeit vom Cyclodextrin-Typ mittels Knetmethode oder Kopräzipitation. Die Assoziatbildung mit [beta]-Cyclodextrinen in Lösung führte zu einer deutlichen Verbesserung der Löslichkeit des Vitamin D3 Analogon. Zur Ermittlung von Löslichkeitsisothermen wurden von den Systemen Phasenlöslichkeitsdiagramme aufgenommen sowie Komplexstabilitätskonstanten berechnet. Zur Charakterisierung der festen dienten DSC-Untersuchungen. Die Anwesenheit von [beta]-Cyclodextrinen führte zu einer Reduktion der Freisetzungsrate der aktiven Verbindung in vitro, besonders im Falle von nativem [beta]-Cyclodextrin. Auch ein deutlich reduzierter Effekt im Hinblick auf die Epidermishyperplasie von Nacktmäusen ist in vivo demonstrierbar. Die Ergebnisse werden im Rahmen der Fragestellung eines Retardierungseffektes sowie einer besseren Hautverträglichkeit, systemischen Nebenwirkungen und lokaler Effektivität des neuen Vitamin D3 Analogon diskutiert. / The aim of the present work was to study the possibility of forming cavitates of a new Vitamin D3 analogue in native [beta]-cyclodextrin, dimethyl-[beta]-cyclodextrin, [beta]-cyclodextrin-polymer, maltosyl-[beta]-cyclodextrin, hydroxypropyl-[beta]-cyclodextrin and carboxyethyl-[beta]-cyclodextrin and to characterize the resulting adducts as regards their composition and properties. Furthermore, in vitro and in vivo studies will be conducted to examine the influence of the [beta]-cyclodextrins in view to retardation effects after incorporation in ointments chosen for the treatment of psoriasis. The solid inclusions are produced with the kneading method or by co-precipitation, depending on the type of cyclodextrin. Phase-solubility diagrams will be drawn and complex stability constants calculated. The formation of associates with the cyclodextrins leads to a substantial improvement of the solubility of the drug. DSC studies are used to characterize the solid associates. The presence of [beta]-cyclodextrins leads to a reduction of the release rate of the active substance in vitro, especially in the case of native [beta]-cyclodextrin. A much reduced effect with regard to epidermal hyperplasia of nude mice is also demonstrable in vivo. The findings are discussed within the framework of the question of retardation and better tolerance as regards skin irritation, systemic side effects and local efficacy of the Vitamin D3 analogue.
418

Coordination of innate behaviors by GABAergic cells in lateral hypothalamus

Carus-Cadavieco, Marta 03 May 2018 (has links)
Der laterale Hypothalamus (LH) reguliert angeborene Verhaltensweisen. Ob und wie die Koordination von hypothalamischen Neuronengruppen Verhaltensübergänge reguliert, blieb jedoch unbekannt. In dieser Arbeit wurde Optogenetik mit neuronalen Ableitungen in verhaltenden Mäusen kombiniert. LHVgat Neurone erhöhten ihre Aktivitätsrate während Übergängen vom NREM-Schlaf zum Wachzustand. LHVgat Zellen projizieren zum Nucleus reticularis des Thalamus (RTN). Optogenetische Aktivierung von Vgat Ausgängen im RTN führte eine starke, frequenzabhängige Inhibierung von RTN Zellen herbei und replizierte Verhaltenszustands-abhängige Aktivitätsraten in RTN Neuronen. Ableitungen von LH Neuronen während Umgebungserkundung ergaben, dass 65% der LH Neurone ihre Aktivitätsrate erhöhten, wenn das Tier began sich fortzubewegen. 'Top-down’ Vorderhirn Innervation des LH erfolgt größtenteils durch Signale ausgehend vom lateralen Septums (LS). Während spontaner Umgebungserkundung und freiem Zugang zu Futter wiesen der LH und das LS Gamma-Oszillationen (30-90 Hz) auf, welche neuronale Aktivität innerhalb und zwischen diesen beiden Gehirnregionen synchronisierten. Optogenetische Stimulation von Somatostatin-positiven GABAergen Projektionen zum LH mit Gamma-Frequenz förderte die Nahrungssuche und erhöhte die Wahrscheinlichkeit des Betretens der Nahrungszone. Inhibitorische Signale des LS bewirkten eine Unterteilung der LH Neurone: entsprechend ihrer Aktivität im Bezug zur Nahrungsstelle wurden sie während bestimmter Phasen der Gamma-Oszillation aktiviert. Dabei führte optogenetische Stimulation von LS-LH Neuronen mit Gamma-Frequenz keine Veränderung bei der Nahrungsaufnahme selbst herbei. Insgesamt liefert diese Arbeit neue Einsichten über die Funktion der neuronalen Netzwerke des LH, welche durch Signalgebung mit unterschiedlichen Zeitskalen über die Koordination mit vor- und nachgeschalteten neuronalen Netzwerken Übergange zwischen verschiedenen angeborenen Verhaltensweisen regeln. / Lateral hypothalamus (LH) is crucial for regulation of innate behaviors. However, it remained unknown whether and how temporal coordination of hypothalamic neuronal populations regulates behavioral transitions. This work combined optogenetics with neuronal recordings in behaving mice. LHVgat cells were optogenetically identified. LHVgat neurons increased firing rates upon transitions from non-REM (NREM) sleep to wakefulness, and their optogenetic stimulation during NREM sleep induced a fast transition to wakefulness. LHVgat cells project to the reticular thalamic nucleus (RTN). Optogenetic activation of LHVgat terminals in the RTN exerted a strong frequency-dependent inhibition of RTN cells and replicated state-dependent changes in RTN neurons activity. Recordings of LH neurons during exploration revealed that 65% of LH neurons increased their activity upon the onset of locomotion. Top-down forebrain innervation of LH is provided, to a great extent, by inhibitory inputs from the lateral septum (LS). During spontaneous exploration in a free-feeding model, LS and LH displayed prominent gamma oscillations (30-90 Hz) which entrained neuronal activity within and across the two regions. Optogenetic gamma-frequency stimulation of somatostatin-positive GABAergic projections to LH facilitated food-seeking, and increased the probability of entering the food zone. LS inhibitory input enabled separate signaling by LH neurons according to their feeding-related activity, making them fire at distinct phases of the gamma oscillation. In contrast to increased food intake during optogenetic stimulation of LHVgat cells, food intake during gamma-rhythmic LS-LH stimulation was not changed. Overall this works provides new insight into the function of LH circuitry, that employs signalling at different time scales, which, in coordination with upstream and downstream circuits, regulates transitions between innate behaviors.
419

Influência do hospedeiro (CHO) e da estratégia de cultivo nas estruturas glicídicas e propriedades moleculares da tireotrofina humana / INFLUENCE OF THE HOST (CHO) AND OF THE CULTIVATION STRATEGY ON GLYCAN STRUCTURES AND MOLECULAR PROPERTIES OF HUMAN THYROTROPHIN

João Ezequiel de Oliveira 07 December 2007 (has links)
Neste trabalho foi desenvolvida pela primeira vez uma estratégia de purificação com duas etapas, uma cromatografia de troca iônica e uma cromatografia líquida de alta eficiência em fase-reversa (RP-HPLC), para obter um hTSH derivado de CHO (r-hTSH-IPEN), que mostrou-se rápida e prática, permitindo um rendimento de 70% e uma pureza > 99%. Um aumento de ~60% na produtividade de r-hTSH-IPEN foi observado quando condições de cultura celular foram alteradas de 5% de CO2 para ar (0,03% CO2). A qualidade dos produtos obtidos em ambas as condições foi avaliada com relação à estrutura dos N-glicanos, aos isômeros de carga e à atividade biológica em comparação com a única preparação comercial conhecida (Thyrogen®) e com uma preparação de referência de origem hipofisária (p-hTSH) do National Hormone and Pituitary Program (NIDDK, EUA). Os N-glicanos identificados nas preparações recombinantes foram do tipo complexo, apresentando estruturas bi-, tri- e tetra- antenárias, algumas fucosiladas, sendo 86-88% sialiladas com níveis variáveis. As três estruturas mais abundantes foram monosialiladas, representando ~69% de todas as formas identificadas nas três preparações. A principal diferença foi encontrada em termos de antenaridade, com 8-10% mais estruturas bi-antenárias na ausência de CO2 e 7-9% mais estruturas tri-antenárias na presença de CO2. No caso do p-hTSH foram identificadas estruturas do tipo complexo, com alta-manose e híbridas, a maioria delas contendo resíduos terminais de ácido siálico e/ou sulfato. As duas estruturas mais abundantes contem um ou dois resíduos de sulfato, sendo que no primeiro caso ele inesperadamente se liga a uma galactose. A porcentagem de ligação do ácido siálico à galactose nas conformações 2-3 e 2-6 foi de 68 ± 10% e 32 ± 10% respectivamente. Não foram observadas diferenças fundamentais nos isômeros de carga, nas três preparações recombinantes, os perfis da focalização isoelétrica mostrando seis bandas distintas no intervalo de pI de 5,39 a 7,35. Uma distribuição consideravelmente diferente, com várias formas na região ácida, foi observada, no entanto, para duas preparações hipofisárias. Uma bioatividade ligeiramente superior (p <0,02) foi encontrada para o r-hTSH-IPEN obtido na presença de CO2 quando as preparações foram analisadas com boa precisão por um simples bioensaio em dose única; esta atividade, no entanto, não é significativamente diferente da atividade do Thyrogen, as duas preparações sendo 1,6 e 1,8 vezes mais potentes do que a preparação de referência (p-hTSH). Podemos concluir que, pelo menos para o caso dos r-hTSH derivados de CHO, diferentes condições de cultivo não afetam significativamente as estruturas dos N-glicanos, distribuição de isómeros de carga ou atividade biológica. Thyrogen e r-hTSH-IPEN, quando comparados com p-hTSH-NIDDK, apresentaram cerca de 7% de aumento da massa molecular determinada por MALDI-TOF-MS. Esta técnica, que permite uma avaliação exata da massa do heterodímero, apresentou valores de MR de 29611, 29839 e 27829, respectivamente. Diferenças significativas foram encontradas entre o r-hTSH e o p-hTSH pelo que se refere às propriedades hidrofóbicas, avaliadas por RP-HPLC. Também foram observadas diferenças relacionadas à composição de carboidratos, principalmente de ácido siálico e galactose, tendo sido encontrado um menor teor destes resíduos no p-hTSH. / A novel, fast and practical two-step purification strategy, consisting of a classical ion exchange and a reversed-phase high performance liquid chromatography (RP-HPLC), for rapidly obtaining CHO-derived hTSH, was set up providing r-hTSH with 70% yield and > 99% purity. A consistent increase of ~60% in the secretion yields of r-hTSH-IPEN was observed by changing cell culture CO2 conditions from 5% CO2 to air environment (0.03% CO2). The overall quality of the products obtained under both conditions was evaluated for what concerns N-glycan structure, charge isomers and biological activity in comparison with a well known recombinant biopharmaceutical (Thyrogen®) and with a pituitary reference preparation (p-hTSH) from National Hormone and Pituitary Program (NIDDK, USA). The N-glycans identified in the recombinant preparations were of the complex type, presenting bi-, tri- and tetra-antennary structures, sometimes fucosylated, 86-88% of the identified structures being sialylated at variable levels. The three most abundant structures were monosialylated glycans, representing ~69% of all identified forms in the three preparations. The main difference was found in terms of antennarity, with 8-10% more bi-antennary structures obtained in the absence of CO2 and 7-9% more tri-antennary structures in its presence. In the case of p-hTSH, complex, high-mannose and hybrid N-glycan structures were identified, most of them containing sialic acid and/or sulphate terminal residues. The two most abundant structures were shown to contain one or two sulphate residues, one of which unexpectedly bound to galactose. The sialic acid-galactose linkage was also determined, having found that 68 ± 10% was in the 2,6 and 32 ± 10% in the 2,3 conformation. No remarkable difference in charge isomers was observed between the three recombinant preparations, the isoelectric focusing profiles showing six distinct bands in the 5.39 - 7.35 pI range. A considerably different distribution, with more forms in the acidic region, was observed, however, for two native pituitary preparations. When analyzed via a simple and precise single-dose bioassay, a slightly higher bioactivity (p<0.02) was found for r-hTSH-IPEN obtained in the presence of CO2. This potency however, was not significantly different from that of Thyrogen, the two preparations being 1.6-1.8-fold more potent than the reference preparation of p-hTSH. We can conclude that, at least for the case of CHO-derived r-hTSH, different production processes do not greatly affect its N-glycan structures, charge isomer distribution or biological activity. Thyrogen and r-hTSH-IPEN, when compared to p-hTSH-NIDDK, presented about a 7% increased relative molecular mass (MR) determined by MALDI-TOF-MS analysis. This technique, allowing accurate heterodimer mass determinations, provided MR values of 29611, 29839 and 27829, respectively. Significant differences in hydrophobic properties, evaluated by RP-HPLC, were found for r-hTSH and p-hTSH. Also differences related to carbohydrate moiety, mainly in the amount of sialic acid and galactose, were found for these preparations, a much lower content of these sugar residues being observed in p-hTSH
420

Ticp e liga Ti-13Nb-13Zr com diferentes tratamentos de superfície-testes in vitro e in vivo / Ticp and Ti-13Nb-13Zr alloy with different surface treatments in vitro and in vivo tests

Carola Gomez Agreda 12 April 2013 (has links)
O titânio e suas ligas são biomateriais metálicos extensamente utilizados em aplicações médicas e odontológicas, apesar de não formarem ligação química com o osso circundante. Por isto é desejável técnicas que proporcionem a bioatividade na superfície desses metais. A proposta deste estudo foi avaliar e comparar, por testes in vitro e in vivo o comportamento de Ticp e da liga Ti-13Nb-13Zr utilizando diferentes tratamentos de superfície frente à formação do recobrimento biomimético e ao processo de osteointegração. Foram utilizadas placas comerciais de Ti e amostras da liga e de Ticp, obtidas por M/P. As amostras foram submetidas a quatro diferentes tratamentos de superfície (padrão - tratamento alcalino; 1°- tratamento alcalino e térmico; 2°- tratamento ácido e alcalino; 3º- tratamento alcalino, CaCl2, térmico e água quente), analisadas quanto à formação de apatita em SBF em períodos de 1 a 21 dias. Os recobrimentos obtidos foram caracterizado por MEV e DRIFT. Para a avaliação in vivo dos implantes, obtidos por M/P, de Ticp e da liga, com e sem tratamentos superficiais, foram utilizados coelhos adultos machos. A avaliação teve duração de 7 semanas em que foram aplicados marcadores celulares ósseos em tempos e sequência específicos do pós-operatório. Na avaliação in vitro, os recobrimentos de maior espessura foram nas amostras obtidas por M/P, comparativamente à amostra laminada. Todos os tratamentos foram efetivos na promoção da bioatividade. O 2º tratamento obteve recobrimento com maior espessura nos períodos avaliados para todas as superfícies. Na avaliação in vivo, ocorreu crescimento ósseo com osteointegração em todos os implantes com e sem tratamentos superficiais. O crescimento ósseo na interface osso/implante ocorreu de forma contínua em todo o período de reparação para o Ticp, o Ticp com tratamento padrão, o Ticp com o 2º tratamento e a liga com o 1° tratamento; e ocorreu de forma mais intensa no primeiro e terceiro período de reparação para os demais implantes. Os resultados dos testes in vitro e in vivo não são passíveis de analogia direta neste estudo, pois forneceram informações importantes sobre a formação, morfologia e taxa de aposição do recobrimento aos diferentes tratamentos de superfície e a efetividade da osteointegração destes tratamentos de superfície em modelo animal. / Titanium and its alloys are widely used metallic biomaterials in medical and dental applications for patient rehabilitation. However, these materials cannot bond with surrounding bone. For this reason, it is desirable to provide a bone-bonding ability for metallic surface. The aim of this study was to evaluate and compare in vitro and in vivo tests of Ti and Ti-13Nb-13Zr alloy subjected to different surface treatments. Laminate titanium plates and Ti and alloy Ti samples obtained by powder metallurgy were used in this study. The samples were subjected to four different surface treatments (pattern- alkali treatment; 1°- alkali and heat treatments; 2°- acid and alkali treatments; 3°- alkali, CaCl2,heat and hot water treatments) and evaluated for apatite coating in SBF for periods of 1 to 21 days. The coated specimens were analyzed by SEM (surface and cross section) and DRIFT. For in vivo evaluation of osseointegration were used Ticp and alloy implants obtained by powder metallurgy with and without surface treatments in male adult rabbits. The evaluation was 7 weeks which were applied bone cell markers at selected times. In vitro evaluation, surfaces obtained by powder metallurgy had a coating of greater thickness when compared to the laminate surface. All treatments were effective in promoting the bioactivity. The 2nd treatment provided coating thicker in the evaluation periods for all surfaces. The osseointegration occurred in all implants with and without surface treatments. However, growth in the bone/ implant interface was continued all over repair period for Ticp, Ticp with pattern treatment, Ticp with 2nd treatment and alloy with 1st treatment. Bone growth in interface occurred more intensely for first and third period to repair for remaining implants. In vitro and in vivo tests are not liable to direct analogy in this study because provided important information on the formation, morphology and apposition rate of coating on different surface treatments and the effectiveness of osseointegration in animal model.

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