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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.
841

Estudo epidemiológico de Leishmaniose Tegumentar Americana (LTA) no município de Itambaracá, região norte do Estado do Paraná, Brasil, em áreas de influência do complexo hidrelétrico na bacia do rio Paranapanema, 2004-2006 / Epidemiological study of American Cutaneous Leishmaniasis (ACL), in northern Paraná State, Brazil, in areas around the hydroelectric plants on the Paranapanema river, 2004 -2006.

Cruz, Mariza Fordelone Rosa 29 February 2008 (has links)
Resumo. Foi realizado um estudo epidemiológico para avaliação dos fatores determinantes para a transmissão da LTA. O estudo foi realizado na área urbana, periurbana e rural da cidade de Itambaracá, incluindo a Vila Rural e as localidades de Porto Almeida e São Joaquim do Pontal, as duas últimas próximas à área impactada pelas hidrelétricas de Canoas I e II, no rio Paranapanema. Capturou-se de fevereiro de 2004 a junho 2006, 3.187 flebotomíneos. As espécies predominantes foram Nyssomyia neivai (34,36%), Pintomyia pessoai (32,57%), Migonemya migonei (11,61%), Nyssomyia whitmani (8,82%) e Pintomyia fischeri (2,73%) todas elas com capacidade de transmissão da doença. Para Ny neivai, houve predominância de machos e para as outras espécies vetoras, as fêmeas prevaleceram, com diferença estatística significante (p<0,001). As espécies mais abundantes, segundo o índice de abundância das espécies padronizado, foram Ny neivai, Pi. pessoai, Ny whitmani, Br. brumpti, Mg migonei e Pi fischeri. As maiores freqüências e diversidade das espécies foram encontradas na localidade de Porto Almeida (PA), seguida por São Joaquim do Pontal (SJP). Ny neivai apresentou médias sazonais mais elevadas e na distribuição mensal, picos em fevereiro, maio e outubro. A maior média horária desta espécie foi registrada das 19:00 às 20:00 h (1,2) mas mostrou-se ativa das 23:00 às 10:00 h da manhã. A prevalência de Acs da classe IgG para LTA em RIFI, na população humana foi de 6,73%, nos caninos de 1,75% e nos equídeos de 16,0 %. Em EIE/ELISA, a prevalência para os caninos foi de 16,49%. Na PCR, todos os cremes leucocitários correspondentes à soros reagentes a Acs da classe IgG (humanos), e Ac totais (eqüinos e caninos) foram negativos para Leishmania sp. No inquérito sócio econômico, verificou-se que a população entrevistada em sua maioria pertence à etnia branca e à faixa etária de 30-50 anos, recebem em torno de dois salários mínimos, possuem ocupações voltadas à agricultura e pecuária, nível de escolaridade fundamental (1º grau), habita casas de alvenaria, possuem animais domésticos com seus abrigos próximos às casas. Realizam atividades de trabalho e lazer em áreas de risco em proximidades às matas, áreas com animais silvestres e domésticos e com presença de matéria orgânica, que são fatores atrativos aos flebotomíneos. A população entrevistada, de uma forma geral, desconhece os aspectos da transmissão da LTA. Observou-se em todas as localidades amostradas a presença de flebotomíneos, com predominância de cinco espécies com capacidade vetorial de agentes da LTA, destacando-se Ny. Neivai , incluindo os peridomicílios. Houve transmissão ativa da doença, ocorrendo dois casos notificados e autóctones, em área de baixa freqüência de espécimes. A soroprevalência na população humana (6,73%) foi considerável, embora seja uma área de baixa ocorrência da doença. Nas localidades onde havia um foco mais recente da doença, em SJP, os cães e eqüinos apresentaram sorologia positiva. A alta prevalência de reagentes na sorologia observada em eqüídeos sugere que estes animais poderiam ser usados como sentinela para a detecção precoce da circulação do agente da LTA nas áreas estudadas. / Abstract. An epidemiological study was carried out in the urban area of Itambaracá and rural areas of the same municipality, including Vila Rural, Porto Almeida and São Joaquim do Pontal, to investigate the phlebotomine fauna and behavioral aspects of its species and also some determining factors of the transmission of American cutaneous leishmaniasis (ACL). The last two localities mentioned are situated close to the areas impacted by the Canoas I and II hydroelectric plants on the Paranapanema river. A total of 3,187 phlebotomines were captured between February 2004 and June 2006. Nyssomyia neivai predominated (34.36%), followed by Pintomyia pessoai (32.6%), Migonemyia migonei (11.6%), Nyssomyia whitmani (8.8%) and Pintomyia fischeri (2.7%), all of them implicated in the transmission of the disease. Regarding Ny. neivai, males predominated over females which may indicate the proximity of its breeding places to the capture sites. As for all the other vector species, the females were predominant, with significant statistical differences (p < 0,001). Ny neivai, Pi. pessoai, Ny. whitmani, Br. brumpti, Mg. migonei and Pi. fischeri presented the highest values for the species standardized abundance index. The greatest frequencies and diversity of the species were found at Porto Almeida (PA), a locality situated close to a well preserved forest fragment and secondly at São Joaquim do Pontal (SJP), with degraded forest. Of all the species, Ny. neivai presented the highest monthly averages with the main peak occurring in successive months of April. Its greatest hourly average was registered at 19:00-20:00 hours, but the species presented activity from 23:00 p.m. to 10:00 a.m. The prevalence of Ac IgG class, serum-reagents for Leishmania obtained with RIFI from the human, canine and equine populations was 6.73% (20/297), 1.75% (5/285) and 16% (8/50), respectively. A prevalence of 16.4% was observed by the EIE/ELISA test only for the canine population. The buffy-coat of all the reagent human and animal blood samples was tested by the polymerase chain reaction (PCR) to investigate the presence of Leishmania, with negative results. In the socioeconomic survey, it was found that the majority of the people interviewed belonged to the white ethnic and 30-50 year-old groups, earning two minimum salaries, exercising occupations associated with agriculture and livestock breeding, of fundamental school level, inhabiting brick houses and keeping pets and domestic animals in and around them. They exercise their work and leisure activities in risk areas close to forest fragments, thus in areas containing both wild and domestic animals with the presence of organic matter, which attract the sandflies. The population interviewed was, in general, ignorant of the facts involved in ACL transmission. Sandflies were observed at all the sites sampled, with the predominance of five vectors of the ACL agents, with Ny. neivai, the main vector in all three areas, also being captured in the peridomiciles. Active transmission of the disease, with two cases registered, was observed at sites with very low frequency of this sandfly. The serum prevalence in the human population (6.73%) was considerable, despite this being an area of few registered ACL cases. In the localities in which there was a more recent focus of the disease, in SJP, the dogs and equines presented positive serology. The high prevalence of equine serum reagents suggests that these animals could be used as sentinels for the early detection of the presence of the ACL agent in the area studied.
842

Cultivo de célula BHK-21 C13 em meio de cultura livre de soro fetal bovino adaptada para crescimento em suspensão / Cell bhk-21 c13 culture in the means of free culture of fetal bovine serum adapted for suspension growth

Leme, Jaci 14 December 2016 (has links)
Células de mamíferos são os hospedeiros mais frequentemente utilizados para a fabricação de proteínas biofarmacêuticas e para a produção de vacinas virais, A qualidade é um elemento-chave para o estabelecimento de um processo de bioconversão eficiente. No presente trabalho utilizamos a linhagem de células BHK- 21C13(Baby Hamster Kidney) adaptadas para cultivo em suspensão. O uso de Soro Fetal Bovino (SFB) é tradicionalmente utilizado, sendo considerado um suplemento universal, pois permite o crescimento em várias linhagens de células de mamíferos; porém, uso de SFB apresenta risco de infecção por prions, variabilidade entre lotes e aumento no custo em etapa de purificação (Downstream processing). O objetivo do presente trabalho foi comparar o cultivo de células BHK-21 C13 entre dois meios suplementados com SFB e sem SFB, através do estudo cinético para cultivo em suspensão estático e agitado com frascoT, frasco spinner e biorreator, respectivamente. Os parâmetros; Xmáx e &#181;máx, não foram significativamente influenciados pelo meio de cultura em cultivo estático, em cultivo com agitação em frasco spinner e também no cultivo em biorreator. O tempo de duplicação ficou próximo para todas as condições testadas. A produtividade alcançada foi: 0,032x106 cel/mL.h-1 para o meio com SFB e 0,031 X106 cel/mL.h-1 para o meio sem SFB. Ao final do processo foi possível obter uma concentração celular em torno de 4,7x106 cel/mL, tanto para o cultivo com SFB quanto para o cultivo sem SFB. Dessa forma, o uso de meio de cultivo sem SFB não alterou os principais parâmetros cinéticos, não apresentando as desvantagens do uso do SFB. / Mammalian cells are the most frequently used hosts for the production of biopharmaceutical proteins and viral vaccines. Quality is a key element for the establishment of an efficient bioconversion process. In this work, we used the cell line Baby Hamster Kidney C13 (BHK-21 C13) adapted to suspension culture was used. Fetal Bovine Serum (FBS) is traditionally used and it is considered a universal insert due to its power to increase cell growth in this kind of animal cells. However, the utilization of FBS introduces risks of infection from prions, variability between batches and increase in cost associated to purification stages (downstream processing). This work aimed to compare the kinetic behaviors of BHK-21 C13 cells in two media supplemented with FBS and without FBS using both one static and two suspension systems, T-flask, spinner flask and bioreactor respectively. The parameters; Xmax and &#181;max were not significantly influenced by the culture medium in T- flask culture static, in spinner flask cultivation and were neither significantly influenced by growing in culture media stirred bioreactor. The doubling time was close to all conditions tested. At the end of the growth phase it was possible to obtain a nearby cell concentration of 4.7 x 106 cells / ml, both for cultivation with FBS as for FBS without cultivation. Thus, the use of culture medium without FBS did not affect the main kinetic parameters. Besides, it does not show the disadvantages of culture media using FBS.
843

Diferentes metodologias para isolamento, expansão e caracterização de células-tronco derivadas de tecido adiposo humano. / Different methodologies for isolattion and cultivation human adipose-derived stem cells.

Fuoco, Natalia Langenfeld 16 September 2014 (has links)
Os procedimentos para uso clínico de células-tronco derivadas de tecido adiposo (CT-TA) exigem grandes quantidades de células, por isso, em geral os protocolos envolvem a expansão e cultura celular in vitro. No entanto, as metodologias utilizadas rotineiramente para o cultivo de CT-TA envolvem a utilização de componentes xenobióticos, como a colagenase e o soro fetal bovino (SFB), que representam riscos potencias de reações imunológicas e transmissão de doenças infecciosas. Sendo assim, pretendeu-se no presente estudo analisar diferentes parâmetros metodológicos para isolamento e expansão de CT-TA, na ausência de componentes xenobióticos. Para tanto, as células-tronco foram isoladas por digestão enzimática ou dissociação mecânica e submetidas à expansão na presença de SFB ou lisado de plaquetas humano (LP). Os resultados mostraram que a metodologia de dissociação mecânica representa uma alternativa viável e eficiente para cultivo de CT-TA, e que o emprego de LP como suplemento para o meio de cultura aumentou de forma significativa a proliferação celular. Em função desses resultados, pode-se concluir que é possível a implementação de técnicas de isolamento e expansão de CT-TA, prescindindo-se de componentes xenobióticos. / The procedures for the clinical use of adipose-derived stem cells (ASC) require large amounts of cells, so in general protocols involve culture and cell expansion in vitro.However, the methods routinely used for the culture of ASC involves the use of xenobiotic components, such as collagenase and fetal bovine serum (FBS), that may representing potential risk of immunological reactions and the risk of transmission of infectious diseases. Thus, it was intended in this study to analyze different methodological parameters for the isolation and expansion of ASC in the absence of xenobiotic components. For this, stem cells were isolated by enzymatic digestion and mechanical dissociation and were submitted to expansion in the presence of FBS or human platelet lysate (PL). The results showed that the mechanical dissociation method represents an effective alternative to growing ASC, and that the use of PL as a supplement to the culture medium significantly increased cellular proliferation. In view of these results, we can conclude that it is possible to implement techniques for isolation and expansion of ASC, dispensing xenobiotic components.
844

Inibição do estresse do retículo endoplasmático restaura o conteúdo de ABCA-1 e o efluxo de colesterol em macrófagos tratados com albumina modificada por glicação avançada / Inhibition of endoplasmic reticulum stress restores the ABCA-1 protein level and cholesterol efflux in advanced glycated albumin-treated macrophages

Castilho, Gabriela 14 August 2012 (has links)
Produtos de glicação avançada (AGE) prejudicam o metabolismo de lipoproteínas e o transporte reverso de colesterol, o que contribui para a aterosclerose no diabete melito (DM). Em particular, a albumina modificada por AGE (albumina-AGE) reduz a remoção de colesterol por diminuir o conteúdo do receptor ABCA-1 em macrófagos. Isto se vincula ao insulto oxidativo e inflamatório, os quais são indutores do estresse do retículo endoplasmático (RE). O objetivo do presente estudo foi avaliar, em macrófagos, os efeitos do tratamento com albumina-AGE sobre o estresse do RE e suas vias adaptativas (UPR), relacionando-os com o prejuízo na expressão do ABCA-1 e efluxo de colesterol celular. Albumina-AGE foi produzida pela incubação de albumina isenta em ácidos graxos com glicolaldeído 10 mM e, albumina controle (albumina-C) com PBS apenas. Albumina foi isolada do soro de pacientes portadores de DM com controle glicêmico inadequado (albumina-DM) ou indivíduos controles (albumina não- DM) por cromatografia para separação rápida de proteínas seguida por purificação alcoólica. Macrófagos de peritônio de camundongos ou macrófagos da linhagem J774 foram tratados com os diferentes tipos de albumina na presença ou ausência de ácido fenil butírico (PBA; chaperona química que alivia o estresse do RE) ou MG-132 (inibidor do sistema proteasomal) por diferentes intervalos de tempo. A expressão de marcadores do estresse do RE, UPR, proteína dissulfeto isomerase (PDI), calreticulina e ubiquitina foi determinada por imunoblot e o conteúdo de ABCA-1, por citometria de fluxo e imunocitoquímica. O efluxo de 14Ccolesterol foi avaliado, utilizando-se apoA-I como aceptora de colesterol. A albumina-AGE induziu aumento tempo-dependente na expressão das chaperonas marcadoras do estresse do RE - Gr78 e Grp94 - e de proteínas da UPR (ATF6 e eIF2-P) em comparação à albumina-C. O conteúdo de ABCA-1 e o efluxo de colesterol foram reduzidos em, respectivamente, 33% e 47% e ambos foram restaurados pelo tratamento com PBA, o qual também reduziu o estresse do RE. A associação entre estresse de RE e redução de ABCA-1 foi confirmada pelo uso da tunicamicina (indutor clássico de estresse do RE), que diminuiu em 61% o conteúdo de ABCA-1, prejudicando em 82% o efluxo de colesterol. A albumina-AGE aumentou o conteúdo total de ubiquitina. A inibição do sistema proteasomal não foi capaz de restaurar o conteúdo de ABCA-1 em células tratadas com albumina-AGE. Em macrófagos expostos à albumina-DM evidenciou-se maior expressão da PDI e calreticulina, com tendência à maior expressão da Grp94. A albumina-AGE (produzida in vitro ou isolada de portadores de DM) induz estresse de RE, o qual se vincula à redução no conteúdo de ABCA-1 e efluxo de colesterol. Estes eventos podem contribuir para a aterosclerose no DM. Chaperonas químicas, que aliviam o estresse do RE, podem ser ferramentas úteis na prevenção e tratamento da aterosclerose / Advanced glycation end products (AGE) disturb lipoprotein metabolism and reverse cholesterol transport, contributing to atherosclerosis in diabetes mellitus (DM). Particularly, advanced glycated albumin (AGE-albumin) reduces cell cholesterol removal by impairing the expression of ABCA-1 in macrophages. This is ascribed to the oxidative and inflammatory stress, conditions that elicit endoplasmic reticulum (ER) stress. In this study it was investigated the effect of AGE-albumin on ER stress and adaptative pathways (UPR) development in macrophages, and its relationship to the reduction in ABCA-1 expression and cholesterol efflux. AGE-albumin was prepared by incubating fatty acid free albumin with 10 mM glycolaldehyde and control albumin (C-albumin) with PBS only. Albumin was isolated from poorly controlled DM patients (DM-albumin) and control individuals (nonDMalbumin) by fast liquid chromatography and purified by alchoolic extraction. Mouse peritoneal macrophages or J774 cells were treated along time with the different types of albumin in the absence or presence of phenyl butiric acic (PBA; a chaperone that aleviates ER stress) or MG132 (a proteasomal inhibitor). The expression of ER stress and UPR markers, protein disulfide isomerase (PDI), calreticulin and ubiquitin was determined by immunoblot and ABCA-1 protein level, by flow cytometry and imunocytochemistry. 14Ccholesterol efflux was evaluated utilizing apo A-I as cholesterol acceptor. AGE-albumin induced a time-dependent increase in the expression of ER stress chaperone markers - Gr78 and Grp94 - and UPR proteins (ATF6 and eIF2-P) in comparison to C-albumin. ABCA-1 content and cholesterol efflux were diminished by, respectively, 33% and 47% and both were recovered by the treatment with PBA. The association between ER stress and ABCA-1 reduction was confirmed by the reduction, induced by tunicanycin (a classical ER stress inductior) in ABCA-1 protein level (61%) and cholesterol efflux (82%). AGE-albumin increased the amount of cellular total ubiquitin. The inhibiton of proteasomal system was unable to restore ABCA-1 protein level in cells treated with AGE-albumin. In macrophages exposed to DM-albumin a higher expression of PDI and calreticulin was observed together with a trend of enhanced Grp94 expression. In conclusion, AGE-albumin (produced in vitro or isolated from DM patients) induces ER stress which is related to the reduction in ABCA-1 level and cholesterol efflux in macrophages. These events can contribute to atherosclerosis in DM. Chemical chaperones that alleviate ER stress may be useful in the prevention and treatment of atherosclerosis
845

Estratégias para a produção de fator VIII recombinante (FVIIIr) em uma linhagem humana em condições de cultivo livres de soro e em suspensão / Strategies for the production of recombinant factor VIII (FVIIIr) in a human cell line cultured under serum-free suspension conditions

Caron, Angelo Luis 02 September 2016 (has links)
A hemofilia A é uma doença ligada ao cromossomo X causada pela deficiência do fator VIII da coagulação sanguínea (FVIII). O tratamento disponível consiste na terapia de reposição da proteína do fator VIII derivada do plasma (FVIIIdp) ou recombinante (FVIIIr). Atualmente, dos 7 produtos recombinantes disponíveis no mercado, 6 são produzidos em linhagens celulares de roedores. A expressão dessa proteína em sistemas celulares não-humanos pode gerar uma molécula com perfil de modificações diferente do endógeno, podendo levar a reações imunogênicas e geração de inibidores anti-FVIIIr. Em função disso, novas estratégias de produção têm sido avaliadas, como a utilização de células hospedeiras mais eficientes no que diz respeito ao potencial de expressão da proteína de interesse. Dentre as linhagens de interesse, a linhagem hepática SK-HEP-1 tem se destacado por apresentar altos níveis de expressão do FVIIIr e potencial para o cultivo em suspensão em meios livres de soro fetal bovino (SFB). Dessa forma, o objetivo deste trabalho foi avaliar a produção de FVIIIr na linhagem celular humana SK-Hep-1 comparando duas estratégias para o estabelecimento de processos de produção em condições livres de soro e em suspensão: Estratégia 1 - adaptação para tais condições da linhagem já modificada geneticamente e Estratégia 2 - modificação gênica para a expressão da proteína já em células previamente adaptadas à tais condições. Para a estratégia 1, foram geradas duas linhagens recombinantes produtoras de FVIIIr, SK-HEP-F8/Neo-E1 e SK-HEP-F8/GFP-E1 aderentes e em cultivos suplementados com SFB. Na caracterização da cinética e produção do FVIIIr as linhagens apresentaram taxas específicas máxima de crescimento (?max) de 0,064 e 0,0031h-1 produzindo 1,0 e 0,78UI/mL de FVIIIr, respectivamente. Diversos protocolos de adaptação foram empregados, entretanto, não foi possível obter sucesso na adaptação das linhagens recombinantes para condições livres de soro e em suspensão. Para a estratégia 2, as células SK-HEP-1 selvagens adaptadas ao meio de cultura livre de SFB SFMII apresentaram um valor de ?max de 0,0186h-1 e Xmax de 1,9x106cels/mL. Para as etapas de modificação gênica da linhagem selvagem foram utilizados os mesmos vetores lentivirais empregados para a geração das células recombinantes aderentes, pLVmpsvFVIII?B-Neo e pLVCMVFVIII?B-GFP. Para o primeiro, não foi possível gerar uma linhagem produtora do FVIIIr. Para o segundo, foi possível obter duas linhagens produtoras do FVIIIr com 0.14 e 0.12IU/mL de atividade pelo ensaio cromogênico. O presente trabalho mostrou que a linhagem humana Sk-Hep-1 é apropriada para a produção de altos níveis de FVIIIr. No entanto, maiores esforços devem ser voltados ao desenvolvimento de meios de cultura livres de soro específicos para a linhagem para possibilitar a produção eficiente do FVIIIr em suspensão em meios livre de soro. / Hemophilia A is a genetic X-linked disorder caused by the coagulation factor VIII (FVIII) deficiency. The current treatment is the replacement therapy with plasma derived FVIII (pdFVIII) or recombinant FVIII (rFVIII) products. Nowadays, of the seven products available in the market, six are produced in rodent expression systems, which can result in a rFVIII molecule with different post-translational modifications and may lead to immune responses to non-human epitopes. Therefore, new production strategies have been evaluated, as the use of more efficient hosts in terms of protein expression potential. Among potential cell lines, the hepatic SK-HEP-1 cell line features high levels of rFVIII production and potential for serum-free suspension culture. In face of the exposed above, the goal of this study was to evaluate rFVIII production in the SK-HEP-1 human cell line comparing two strategies for the establishment of production process in a suspension serum-free condition: strategy 1 - adaptation to these conditions of a genetic modified cell line; strategy 2 - genetic modification of an already adapted cell line to rFVIII protein expression. For strategy 1, two adherent rFVIII producer cell lines were established in serum containing medium, SK-HEP-F8/Neo-E1 e SK-HEP-F8/GFP-E1. Characterization of cell growth and rFVIII production showed a maximum specific growth rate (?max) of 0.064 and 0.00311h-1 with rFVIII production of 1.0 and 0.78UI/mL, respectively. Different adaptation protocols were used; however, it was not possible to adapt the recombinant cell lines to growth in suspension serum-free conditions. For strategy 2, the wildtype SK-HEP-1 cell line adapted growth in SFMII BSF medium, showed a ?max of 0.0186h-1 and a maximum cell concentration (Xmax) of 1.9x106cells/mL. For the genetic modification, it were employed the same lentiviral vectors used for the recombinant adherent cells generation, pLVmpsvFVIII?B-Neo and pLVCMVFVIII?B-GFP. For the first, no attempts were successful. For the second, it was possible to generate two rFVIII producer populations with 0.14 and 0.12IU/mL activity, measured by chromogenic assay. These results demonstrate that the SK-HEP-1 cell line is appropriate for the production of high levels of rFVIII. Nevertheless, efforts should be made in developing specific medium to support efficient rFVIII production in suspension and suspension serum-free conditions.
846

Protein stability : impact of formulation excipients and manufacturing processes in protein-based pharmaceuticals

Darkwah, Joseph January 2017 (has links)
Presently, over 300 proteins or peptide based therapeutic medicines have been approved by the FDA owing to advances in protein engineering and technology. However, majority of these protein-based medications are unstable or have limited shelf life when in aqueous form. During pre-formulation and manufacturing, various technological processes including mixing, dissolving, filling (through pipes) can produce strong mechanical stresses on proteins. These stresses may cause the protein molecule to unfold, denature or aggregate. To improve stability upon formulation, they may be manufactured as freeze dried cakes that requires reconstitution with a buffer or water prior to administration. Although it has been successful in improving the stability of protein-based formulations, the freeze drying process itself also contributes to protein aggregation. This process introduces other stresses such as freezing, thawing and drying. In addition to these stresses, the agitation processes used during reconstitution may also destabilize the protein’s native structure. Two key processes used in preparation of protein based formulations were studied in this work; mechanical agitation and freeze drying. The aim of this project was to explore the aggregation of proteins that occur due to the various technological processes typical in the production of protein based formulations. The project has two parts that relates to liquid and solid formulations. In the first part, the effect of different methods of mechanical agitations on BSA protein was investigated. In the second part, the focus was on the effect of formulation (i.e. the application of amino acids) on aggregation of protein (BSA) in freeze dried formulations. Arginine and lysine were added individually into protein-based freeze-dried formulation to study their potential of improving the stability of the proteins during manufacturing, storage and reconstitution. In the formulation development, additional excipients were added to prevent moisture uptake due to the hygroscopic properties of the amino acids and to provide lyo- and cryo- protection for the protein molecule during freeze drying. Without further purification, BSA solutions prepared by using sonication, low shear rotor mixer or high shear tube/pipe mixing were studied using dynamic light scattering (DLS). Thioflavin T assay and turbidimetry analysis were used as complementary studies. In protein-based freeze dried formulations, at accelerated storage conditions, the presence of aggregates were studied in samples containing arginine or lysine using ThT assay and turbidimetry analysis. Characterisation of the freeze dried cakes was performed relative to their moisture sorption, cake shrinkage, mechanical properties and morphology using various analytical techniques. iv In the BSA solution studies, particle size analysis indicated two distributions for non-agitated BSA solution that corresponds to the average particle sizes of BSA molecules and their aggregates. Under mechanical stresses (all types), the intensity of distribution centered ≈ 7.8 nm reduces and broadens as the agitation time increases, indicating a reduction in the amount of “free” BSA macromolecules. The second distribution, as a result of increasing agitation time or shear intensity, reveals a significant shift towards larger sizes, or even splits into two particle size populations. These particle size growths reflect the formation of aggregates due to intensive collisions and, as a result, partial unfolding followed by hydrophobic interactions of exposed non-polar amino acids. UV spectra showed that aggregation in both low shear and mechanical vibration agitations were lower compared to the high shear stress. When compared to non-agitated BSA solution, ThT assay recorded ≈15 times higher fluorescence emission from the high shear samples, ≈2 times fluorescence emission from low shear and ≈6 times fluorescence emission from mechanical vibrations. Thus all the three agitation methods showed a good correlation between the results. The second part of this project was performed in three stages. In the initial 2 stages, 2- and 3-excipients component system were investigated to develop an optimal preliminary formulations which will be used in the final protein based 4-components formulations. From the 1st stage (ArgHCl/LysHCl + sugar/polyol), among 4 tested excipients (polyol and sugar), mannitol was observed to have resisted moisture uptake by the highly hygroscopic ArgHCl/LysHCl amino acids. However, mannitol is considered a good cryoprotector but has poor lyoprotection properties. Therefore, in the following stage, a 3rd excipient (in a 3-excipients component system) sucrose or trehalose, was introduced into the formulation. The formulation was made up of 20% ArgHCl (LysHCl), and various ratios of mannitol and sugar were explored. The criteria for selecting the best systems were based on ideal physicochemical properties i.e. moisture uptake, shrinkage, mechanical properties, matrix structure and appearance, and thermal properties. The final stage was the formulation of a 4-components system comprising the three excipients and combinations selected from the stage 2 studies, and the addition of BSA as the model protein. To study aggregation in this system, a freeze dried 4-components excipient/protein system was reconstituted and incubated at accelerated storage conditions over time. Fluorescence spectroscopy and turbidimetry were used to study aggregation of proteins, moisture uptake kinetics with gravimetric balance, and thermal analytical techniques were used to characterise the freeze dried cakes with and without BSA protein. This study represented a systematic analysis of aggregation of proteins in both liquid and solid formulations. Some of the novel aspects of this study include: v 1. The new experimental results obtained for aggregation of proteins in solution subjected to mechanical agitations. The high shear stress created by syringe agitation, simulated the real situation in post manufacturing process during filling through narrow pipes, and has been shown here to strongly affect the aggregation of protein macromolecules. 2. The development of a methodical approach for optimization of multi component (up to 4 excipients) protein based formulations. 3. The unexpected non-linear behavior of the physicochemical properties of the 3-excipients component system as a function of composition. To the best of my knowledge, this novel aspect has not been previously reported in literature. 4. Application of amino acid in protein based formulations has shown the inhibition of aggregation of BSA, with the highest effect observed with ArgHCl. The results of this study coincide with the conclusions published previously for aggregation of proteins in solution.
847

Comparação entre as concentrações de tetraciclina no plasma, líquido sinovial e leite de vacas com doença do casco, submetidas às administrações intravenosa e intravenosa regional e sua implicação na presença de resíduos no leite / Comparision among tetracycline concentrations in plasma, synovial fluid and milk in cows with lameness in foot, subjected to intravenous and regional intravenous administration and their implications in the presence of residues in milk

Esteban, Cláudia 26 August 2003 (has links)
O presente trabalho visa desenvolver métodos que permitam determinar as concentrações de tetraciclina, por Cromatografia Líquida de Alta Eficiência, no plasma e líquido sinovial, além de analisar as concentrações correspondentes em leite de gado leiteiro em lactação submetidos aos tratamentos intravenoso e intravenoso regional. Desta forma, objetivando determinar a depuração da tetracic1ina no organismo dos animais tratados, a concentração do fármaco no sítio de ação e a quantidade residual em leite, as amostras biológicas foram colhidas e quantificadas em diferentes tempos pré e pós-administração do fármaco. Os métodos analíticos validados apresentaram linearidade, limite de detecção, quantificação, exatidão, precisão e recuperação adequados à quantificação do antibiótico nas matrizes biológicas estudadas. As amostras de leite de animais tratados com o medicamento por via intravenosa regional, não apresentaram resíduos após 120h da administração do fármaco. O mesmo ocorreu plasma e líquido sinovial após 48 h. Através da administração via intravenosa do medicamento foram observados resíduos no leite em todos os tempos avaliados, ao passo que no plasma e líquido sinovial, a presença do princípio ativo não foi detectada após 72 horas pós-tratamento. / The purpose of the present work is to develop methods which allow the determination of tetracycline by High Pressure Liquid Chromatography in serum, synovial fluid, as well as analyze the corresponding milk concentrations in milk cows subjected to intravenous and regional intravenous treatment. Therefore, aiming to determine the clearance of tetracycline in the body of the treated animals, the concentration of the active principle in the action site and the residual quantity in milk, biological matrices were collected at different times. The validated analytical methods depicted suitable linearity, detection and quantification limits, accuracy, precision and recovery, allowing the quantification of the antibiotic in the studied biological matrices. In relation to the milk samples from animals treated with the drug by regional intravenous via, they did not present residues of tetracycline after 120 h post-administration. The values were also null for both serum and synovial fluid after 48 h. Through regional intravenous drug administration, milk residues were observed in all the evaluated times whereas for serum and synovial fluid, the presence of the active principle was not detected after 72h post-treatment.
848

Perfil de ativação de basófilos e evidência de fatores liberadores de histamina na urticária crônica idiopática / Basophils activation profile and evidence of histamine release factor in Chronic Idiopathic Urticaria

Lourenço, Francinelson Duarte 07 December 2009 (has links)
INTRODUÇÃO: A Urticária Crônica é caracterizada pelo aparecimento de pápulas eritematosas, pruriginosas recorrentes e transitórias que duram por mais de seis semanas. Na maioria dos pacientes a causa é indeterminada, definida como idiopática (UCI), entretanto, um sub-grupo apresentam autoanticorpos contra a cadeia alfa do receptor de alta afinidade para IgE (FceRI), que são expressos na superfície de mastócitos e basófilos, tornando-os células alvo nesta doença. OBJETIVOS: Avaliar em pacientes com UCI, submetidos ao teste intradérmico de soro autólogo (ASST), o perfil de ativação dos basófilos, pela intensidade de expressão de marcadores de ativação/desgranulação e pela capacidade dos basófilos em responder aos estímulo com a IL-3 e anticorpo anti-IgE. Além disto, a presença de fator liberador de histamina foi avaliado nos soros dos pacientes. METODOLOGIA: Pacientes com UCI (n= 37) foram selecionados no Ambulatório de Urticária do Departamento de Dermatologia do Hospital das Clínicas da Faculdade de Medicina da USP e submetidos ao ASST. O grupo controle foi constituído por indivíduos saudáveis (n=38). A análise da expressão de FceRI, CD63, CD123 e CD203c em basófilos de sangue periférico foi realizada por citometria de fluxo. No ensaio in vitro de estimulação dos basófilos com anti-IgE, as células foram previamente incubadas com IL-3. O ensaio de liberação de histamina mediada por soros de pacientes com UCI foi realizado com três diferentes doadores de leucócitos e a histamina liberada dosada por ELISA de competição. RESULTADOS: Há um baixo número de basófilos no sangue periférico nos pacientes com UCI, coincidente com o baixo nível sérico de histamina. Os escassos basófilos no sangue periférico mostram elevada expressão de FceRI e uma regulação positiva da expressão de CD203c e CD63, independentemente do ASST. A análise funcional dos basófilos, mostra que somente a incubação com IL-3 recombinante já induz aumento significante da expressão de CD203c e da liberação de histamina dos basófilos de pacientes com UCI, que são intensificados com o estímulo por anticorpos anti-IgE após 15 e 40 minutos em relação ao grupo controle. Já a expressão de CD63 em basófilos após estímulo com anti-IgE, aumentou somente nos basófilos de indivíduos sadios, uma vez que os níveis de expressão basal estavam previamente aumentados. A presença de autoanticorpos liberadores de histamina foi analisada nos soros de pacientes com UCI. Três experimentos independentes foram realizados, evidenciando a ocorrência de 17% de positividade. CONCLUSÕES: Os resultados mostram que na UCI, os basófilos são sensibilizados in vivo, por fatores além dos autoanticorpos anti-FceRI e que funcionalmente, estão hiper-reativos a estímulos imunológicos. A presença de fatores séricos liberadores de histamina, independente do ASST, enfatiza que o teste intradérmico é sugestivo de autorreatividade e não de autoimunidade na UC / INTRODUCTION: Chronic Urticaria is characterized by recurrent, transitory, pruritic and erythematous wheals present for at least six weeks. In most patients the cause is unknown, defined as idiopathic (CIU), however, a sub-group has autoantibodies against the alfa chain of the high affinity IgE receptor (FceRIa) expressed on mast cells and basophils surface making it the target cells in this disease. OBJECTIVES: To evaluate in CIU patients, undergone autologous serum skin test (ASST), the activation profile of the basophils assessed by the expression of activation/degranulation markers and by the ability to release histamine in response to IL-3 priming and cross-linking with anti-IgE antibodies. Furthermore, the presence of histamine releasing factor in sera of patients was evaluated. METHODS: CIU patients (n = 37) were selected from the Dermatological Outpatient Clinic of the Hospital das Clínicas de São Paulo (HC-FMUSP) and submitted to the ASST. The control group consisted of healthy subjects (n=38). The analysis of the expression of FceRI, CD63, CD123 and CD203c on basophils from peripheral blood was assessed by flow cytometry. For the in vitro stimulation with anti-IgE antibodies, the cells were previously primed with human recombinant IL-3. The histamine release assay mediated by sera from patients with CIU was performed with three different donors of leukocytes and released histamine measured by competition ELISA. RESULTS: There is a low number of basophils in peripheral blood of patients with CIU, reflecting a low serum levels of histamine. The scarce basophils in peripheral blood show high expression of FceRI and an up-regulation of CD203c and CD63 marker expression, independently of the ASST. The functional analysis of basophils, revealed that recombinant IL-3 per se induces a significant increase in CD203c expression and the histamine release from basophils of patients with CIU, which are enhanced followed for 15 and 40 minutes of anti-IgE estimulation. The expression of CD63 in basophils upon anti-IgE stimulation, increased only in basophils of healthy individuals, since the baseline levels of CD63 expression on basophils of patients was already up-regulated. The presence of histamine release factors was examined in sera from CIU patients. Three independent experiments were performed, showing the occurrence of 17% of positivity. CONCLUSION: The results show that in CIU, the basophils are primed in vivo due to factor other than autoantibodies anti-FceRI and they have an hyperactive status to the immunological stimuli. The presence of serum histamine releasing factors, independent of the ASST, emphasizes that the intradermal test is suggestive of autorreactivity and not for autoimmunity in UC
849

Tribologie du Ti-6AI-4V et d'un revêtement DLC en fretting : applications au contact tige/col dans les prothèses de hanches modulaires / Tribology of Ti-6AI-4V and DLC coating in fretting : applications to stem/neck contact of modular hip implant

Ding, Haohao 24 October 2018 (has links)
L’utilisation d’un col modulaire lors de la pose d’une prothèse totale de hanche introduit une nouvelle interface, entre la tige et le col, qui est susceptible de s’endommager par fretting lors de la marche. L’alliage Ti–6Al–4V est très largement utilisé pour les tiges et les cols. Cependant, les contacts Ti–6Al–4V / Ti–6Al–4V présentent un frottement élevé et une forte usure adhésive dans les conditions de fretting. Les revêtements DLC (diamond-like carbon) ont été largement utilisés comme revêtements protecteurs pour les pièces métalliques. Ainsi, ils peuvent être introduits dans les contacts entre la tige en Ti–6Al–4V et le col en Ti–6Al–4V. L’objectif de cette thèse est d’étudier les comportements tribologiques du revêtement DLC et de l’alliage Ti–6Al–4V dans les conditions de fretting pour application au contact entre la tige et le col. Les essais de fretting sont menés avec un contact cylindre sur plan sous différentes valeurs d’amplitude de déplacement (± 20 μm, ± 40 μm, et ± 70 μm) et de force normale (entre 200 N et 1 200 N). En outre, les effets de différents revêtements (DLC A et DLC B), différentes rugosités de surface (lisse et rugueuse), différentes positions de revêtement (revêtement sur le plan, sur le cylindre et sur les deux surfaces), différents environnements (dans l’air et dans le sérum de veau) sont analysés. Par ailleurs, l'origine du faible frottement du contact entre Ti–6Al–4V et revêtement DLC est explorée. Les propriétés mécaniques du tribofilm formé sur la surface de Ti–6Al–4V frottée sont également étudiées.Pour les tests de fretting sans revêtement (contact Ti–6Al–4V / Ti–6Al–4V) dans l’air, le coefficient de frottement est élevé, entre 0.8 et 1.2. Le volume d’usure croît avec l’amplitude de déplacement. Pour les tests avec revêtement, le Ti–6Al–4V peut être bien protégé, sous des charges relativement faibles. Le coefficient de frottement (d’environ 0,2) et le volume usé sont faibles. Sous fortes charges, le revêtement est presque totalement éliminé. Le frottement et le volume d'usure sont similaires à ceux des essais sans revêtement. Le revêtement plus dur (DLC A) a de meilleures propriétés tribologiques que le DLC B. Le revêtement sur la surface lisse présente une meilleure performance en fretting que sur la surface rugueuse. Le revêtement sur une surface cylindrique présente une meilleure performance tribologique que sur une surface plane. Le revêtement DLC est plus endommagé lorsqu'il glisse contre un revêtement DLC que contre du Ti–6Al–4V non revêtu. Le revêtement fonctionne mieux en présence de sérum que dans l’air. Un tribofilm est formé sur la surface de Ti–6Al–4V frottée lorsqu'il glisse contre un revêtement DLC sous de faibles charges. Le tribofilm présente une dureté plus élevée, un module de Young plus élevé, un module de compression plus élevé, une limite d'élasticité plus élevé que l’alliage Ti–6Al–4V. Un modèle tribologique est proposé pour la formation du tribofilm et l'explication de l'origine du faible frottement, par une analyse approfondie des surfaces de contact, sur les points de vue mécaniques et chimiques. / The use of modular neck adapter when placing a total hip prosthesis introduces a new interface, between the femoral stem and the neck adapter, which is propitious to fretting damage during walking. Ti–6Al–4V alloy has been widely used in neck adapters and femoral stems. However, the Ti–6Al–4V / Ti–6Al–4V contacts present high friction and severe adhesive wear under fretting conditions. Diamond-like carbon (DLC) coatings have been widely used as protective coatings for metallic parts. Thus, they can be introduced into Ti–6Al–4V neck adapter / Ti–6Al–4V femoral stem contacts.The objective of this thesis is to investigate the tribological behaviors of DLC coating and Ti–6Al–4V alloy under fretting conditions for application to neck adapter / femoral stem contact. Fretting tests are conducted with a cylinder / flat contact under different values of displacement amplitude (±20 µm, ±40 µm, and ±70 µm) and normal force (between 200 N and 1 200 N). Furthermore, the effects of different DLC coatings (DLC A and DLC B), different surface roughness (smooth and rough), different coating positions (coating on the flat, on the cylinder, and on both surfaces), different environments (laboratory air and calf serum) are analyzed. Besides, the origin of low friction of Ti–6Al–4V / DLC coating contact is explored. The mechanical properties of tribofilm formed on the rubbed Ti–6Al–4V surface is studied.For fretting tests without coating (Ti–6Al–4V / Ti–6Al–4V contact) under laboratory air condition, the friction coefficient is high, between 0.8 and 1.2. The wear volume increases with the displacement amplitude. For fretting tests with coating, Ti–6Al–4V can be well protected under relatively low load conditions. The friction coefficient is low (around 0.2) and the wear volume is small. Under high load conditions, the coating is almost totally removed. The friction and wear volume are similar to tests without coating. The harder coating (DLC A) has better tribological property than DLC B. The coating on the smooth surface exhibits better fretting performance than on the rough surface. Coating on a cylindrical surface shows better tribological performance than on a flat surface. The DLC coating is damaged more severely when it slides against a DLC coating than against the uncoated Ti–6Al–4V alloy. The coating performs better under the serum condition than under the laboratory air condition. A tribofilm is formed on the rubbed Ti–6Al–4V surface when sliding against a DLC coating under low load conditions. The tribofilm shows higher hardness, higher Young’s modulus, higher compression modulus, higher yield strength than the Ti–6Al–4V alloy. A tribological model is proposed for tribofilm formation and explanation of origin of low friction, by in-depth analysis of contact surfaces, on mechanical and chemical points of view.
850

Avaliação dos teores de oxitetraciclina por cromatografia a líquido de alta eficiência em gado leiteiro com doença do casco / Oxitetraciclina, Administração intramuscular, Administração tópica, Resíduos em leite, Plasma e líquido sinovial, Medicamentos veterinários, Doença do casco, Cromatografia a líquido de alta eficiência

Esteban, Cláudia 14 April 2008 (has links)
O presente trabalho visa desenvolver métodos analíticos que permitam determinar as concentrações de oxitetraciclina por Cromatografia Líquida de Alta Eficiência, no leite, plasma e líquido sinovial, além de analisar as concentrações correspondentes em gado leiteiro em lactação portadoras de doença do casco submetidos aos tratamentos intramuscular e tópico. Adicionalmente, são tecidos comentários sobre a eficácia clínica destes tratamentos. Desta forma, objetivando determinar a depuração de oxitetraciclina no organismo dos animais tratados, a concentração no sítio de ação e a quantidade residual em leite, as amostras biológicas foram colhidas e quantificadas em diferentes tempos pré e pós-administração do fármaco. Os métodos analíticos validados apresentaram linearidade, limite de detecção, quantificação, exatidão, precisão e recuperação adequadas à quantificação do antibiótico nas matrizes estudadas. Através da administração do medicamento por via intramuscular, observou-se resíduos acima dos limites máximos (100ppb) estabelecidos pela legislação brasileira para oxitetraciclina no leite até 120 horas após a última administração do medicamento pelo esquema seriado de doses. Já pela via tópica, não foram observados valores residuais na matriz biológica. Do ponto de vista clínico, o tratamento tópico foi eficiente nos animais tratados, levando a cura das lesões. Com relação ao tratamento intramuscular, não foram observados resultados satisfatórios, pois a maioria das lesões não regrediu após as administrações. / The purpose of the present work is to develop methods which allow the determination of oxytetracycline by High Pressure Liquid Chromatography in milk, serum and synovial fluid, as well as analyze the corresponding concentration in milk cattle with foot lameness subjected to intramuscular and topical administration of the antibiotic. It is also commented the clinical efficacy of these two treatments. Thus, to determine the clearance of oxytetracycline in the body of the treated animals, the concentration on the site of action, and the antibiotic residue in milk, biological samples have been collected and analyzed for the oxytetracycline content at different times before and after the drug administrations. The validated analytical methods showed suitable linearity, detection and quantification limits, accuracy, precision and recovery, allowing proper quantification of the antibiotic in the studied biological matrices. When administered intramuscular1y, oxytetracycline residues were observed in milk above the maximum limits (100ppb) established by the brazilian legislation up to 120 hour after the last administration of the medicine using multiple doses treatment, whereas on topical use, residues were not observed in this matrix. When analyzing the clinical aspects, topical treatment was very efficient, leading to the healing of the treated animals. In relation to intramuscular treatment, non satisfactory results were observed, as most of lesion did not disappear after the antibiotic administration.

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