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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
251

Albumina modificada por glicação avançada no diabete melito tipo 1 e 2 prejudica o transporte reverso de colesterol e favorece o acúmulo de lípides em macrófagos / Impairment in reverse cholesterol transport and macrophage lipid accumulation induced by advanced glycated albumin drawn from uncontrolled type 1 and type 2 diabetes mellitus patients

Adriana Machado Saldiba de Lima 24 February 2011 (has links)
Produtos de glicação avançada (AGE) são prevalentes no diabete melito e alteram o metabolismo de lípides e lipoproteínas. Neste estudo, avaliou-se a influência da albumina, isolada do soro de indivíduos controles (C, n =12) e de portadores de diabete melito tipo 1 (DM 1, n=13) e tipo 2 (DM 2, n=11), com controle glicêmico inadequado, sobre a remoção de colesterol de macrófagos, o acúmulo intracelular de lípides, o conteúdo do receptor de HDL, ABCA-1 e a captação seletiva de colesterol esterificado de HDL. Além disso, foi determinada a expressão diferencial de genes em macrófagos tratados com albumina C, DM 1 ou DM 2. A concentração plasmática de albumina glicada foi superior no grupo DM 1 e DM 2 em relação ao C e correlacionou-se positivamente com glicemia, hemoglobina glicada e frutosamina. Albumina sérica foi isolada por cromatografia para separação rápida de proteínas e purificada por extração alcoólica. Albumina DM 1 e DM 2 apresentaram maior conteúdo de carboximetil-lisina e apo A-I quando comparada à albumina C. Macrófagos enriquecidos com LDL acetilada e 14C-colesterol foram tratados com albumina C, DM 1 ou DM 2 e, a seguir, incubados na presença ou ausência de apo A-I, HDL3 ou HDL2 para determinação do efluxo de colesterol. Apesar de removerem maior quantidade de colesterol celular, as albumina DM 1 e DM 2 reduziram o efluxo de colesterol mediado por apo A-I (70% e 45%, respectivamente) e HDL2 (55% e 54%, respectivamente) em comparação à albumina C. Com HDL3, a queda no efluxo de colesterol só foi observada em macrófagos expostos à albumina DM 2 (55%). Macrófagos incubados apenas com albumina C, DM 1 ou DM 2 apresentaram conteúdo lipídico semelhante, evidenciado por coloração com Oil Red O. A adição de apo A-I, HDL3 ou HDL2 reduziu o conteúdo lipídico apenas nas células tratadas com albumina C, mas não com albumina DM 1 ou DM 2. A expressão de ABCA-1 foi diminuída 82% e 25% em macrófagos expostos, respectivamente, à albumina DM 1 e DM 2, em comparação às células tratadas com albumina C. As albuminas DM 1 e DM 2 reduziram a captação de 3H colesteril oleoil éter de HDL por células que superexpressam o receptor SR-BI. Estes resultados também foram obtidos com albumina humana modificada in vitro por glicação avançada. As albuminas isoladas dos pacientes diabéticos aumentaram a expressão de receptores envolvidos na captação de LDL modificadas e de proteínas que modulam vias da homeostase do colesterol. Os resultados deste estudo evidenciaram que a modificação in vivo da albumina por glicação avançada prejudica o transporte reverso de colesterol no diabete melito, por reduzir a expressão de ABCA-1 e a remoção de colesterol de macrófagos, bem como a captação seletiva de colesterol esterificado de HDL pelo SR-BI. Independentemente de variação na concentração e composição de HDL, a glicação da albumina pode contribuir para o acúmulo de lípides em macrófagos e gênese da aterosclerose no diabete melito / Advanced glycation end products are prevalent in diabetes mellitus and alter lipids and lipoprotein metabolism. In this study we analyzed the role of albumin, isolated from control individuals (C, n = 12) and uncontrolled type 1 (DM 1, n = 13) and type 2 (DM 2, n = 11) diabetes mellitus patients on macrophage cholesterol removal, intracellular lipid accumulation, expression of the HDL receptor protein level, ABCA-1and the uptake of esterified cholesterol from HDL. It was also investigated the differential gene expression in macrophages treated with C, DM 1 or DM 2 albumin. Glycated albumin was higher in DM 1 and DM 2 groups as compared to C and was positivetly correlated with glycemia, glycated hemoglobin and fructosamine. Serum albumin was isolated by fast protein liquid chromatography and alchoolic extraction. DM 1 and DM 2 albumin presented a higher amount of carboxymethyllysine and apo A-I as compared to C albumin. In order to determine cholesterol efflux acetylated LDL and 14C-cholesterol enriched J- 774 macrophages were treated with C, DM 1 or DM 2 albumin and then incubated in the absence or presence of apo A-I, HDL3 or HDL2. Although presenting a higher ability to remove cell cholesterol by itself, DM 1 and DM 2 albumin reduced cholesterol efflux mediated by apo A-I (70% e 45%, respectively) and by HDL2 (55% e 54%, respectively) as compared to C albumin. With HDL3 the reduction of the cholesterol efflux was only observed in macrophages treated with DM 2 albumin (55%) in comparison to C albumin. Macrophages incubated with C, DM 1 or DM 2 albumin alone presented similar amount of intracellular lipids as assessed by Oil Red O staining. The addition of apo A-I, HDL3 or HDL2 reduced the lipid content in cells treated with C albumin, but not in those exposed to DM 1 or DM 2 albumin. The expression of ABCA-1 was reduced 82% and 25% in macrophages treated, respectively, with DM 1 or DM 2 albumin, in comparison to C albumin. DM 1 and DM 2 albumin reduced the uptake of 3H colesteril oleoyl ether from HDL by SR-BI overexpressing cells. These findings also were obtained when cells were treated in vitro with human serum albumin submitted to advanced glycation. DM 1 and DM 2 albumin enhanced the expression of receptors involved in the uptake of modified LDL and cholesterol homeostasis. Our findings showed that the advanced glycation of albumin that takes place in diabetes mellitus impairs the reverse cholesterol transport efficiency by reducing the ABCA-1 expression and cholesterol exportation to HDL and also by diminishing the uptake of esterified cholesterol from HDL. Independently of changes in HDL composition and concentration, advanced glycated albumin contributes to cholesterol accumulation in macrophages and atherogenesis in diabetes mellitus
252

Estudo da expressão da albumina no desenvolvimento pós-natal do trato reprodutor masculino de murinos / Albumin expression in the postnatal development of murine male reproductive tract

Barbieri, Mainara Ferreira, 1987- 24 August 2018 (has links)
Orientadores: Luis Antonio Violin Dias Pereira, Lúcia Elvira Alvares / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-24T14:05:01Z (GMT). No. of bitstreams: 1 Barbieri_MainaraFerreira_M.pdf: 6077469 bytes, checksum: c80011c6f6fca680e92ac99691a9c348 (MD5) Previous issue date: 2014 / Resumo: A origem da albumina nos órgãos do trato reprodutor masculino tem sido questionada ao longo dos anos sendo sua presença tecidual constantemente atribuída a um mecanismo de extravasamento do plasma sanguíneo para o espaço extravascular intersticial, atribuindo-se ao fígado o papel de sítio de síntese desta proteína no período pós-natal. O padrão de distribuição da proteína albumina nos tecidos epiteliais de órgãos do trato reprodutor masculino reserva questionamentos quanto à veracidade de seu alcance luminal pelo rompimento de suas barreiras hematoteciduais. Carreador de esteroides; estimulador de células de Leydig; mediador do mecanismo parácrino de comunicação entre células de Sertoli e germinativas; promotor de proliferação celular e mediador de mudanças estruturais em membranas celulares, com suposta participação na reação acrossômica e capacitação do espermatozoide são possíveis papéis atribuídos à albumina no trato reprodutor masculino. A associação da proteína albumina a componentes glicídicos não é usual para mamíferos, porém há respaldo a essa hipótese através das PES (glicoproteínas pré-albumínicas epidídimo-específicas de ovinos) e dados de nosso grupo de pesquisa através do epítopo reconhecido pelo anticorpo monoclonal (Amc) TRA 54 (testicular germ cells immunized to rat). Essa dissertação de mestrado retoma a polêmica discussão centrada na presença, origem, localização e função da albumina no trato reprodutor masculino e se propôs, através de uma abordagem cronológica pós-natal (períodos neonatal, pré-púbere, púbere, adulto e idoso) a rediscutir os fundamentos teóricos associados à principal proteína sérica de mamíferos bem como o dúbio perfil de expressão dessa proteína em Ratos analbuminêmicos Nagase (NAR). Nesse estudo, a presença da proteína albumina foi evidenciada por immunoblotting em todos os grupos e períodos do desenvolvimento pós-natal, apresentando padrão distinto de bandeamento para testículos e epidídimos NAR. A localização celular da proteína albumina foi identificada em camundongos, por imunohistoquímica, principalmente no tecido intersticial e nas células da linhagem germinativa. Testículos de ratos Sprague Dawley adultos apresentaram marcação adicional para células de Sertoli. Testículos e epidídimos de NAR mantiveram reatividade intersticial, sugerindo, ainda que em níveis extremamente baixos, a expressão de albumina. Para epidídimos, foi identificado amplo espectro de perfis de imunomarcação das células epiteliais e estereocílios. Ductos deferentes apresentaram, na região proximal ao epidídimo, imunomarcação citoplasmática e, na região distal, marcação de estereocílios e espermatozoides luminais. Perfis de imunomarcação citoplasmática também foram observados em vesícula seminal, próstata e uretra peniana, principalmente, no período adulto. Por fim, a presença de transcritos de RNAm detectados por ensaios de RT PCR (reação em cadeia de polimerase via transcriptase reversa) para testículos e epidídimos foi confirmada desde o período neonatal até idoso, mostrando-se também presente para ducto deferente a partir da puberdade. A abordagem do desenvolvimento pós-natal revelou um pico de maior expressão da albumina no período adulto com início do declínio registrado no período idoso. Como ressalva final, a confirmação da presença de RNAm para órgãos do trato reprodutor masculino não invalida a hipótese da também presença de albumina circulante, sintetizada, em primeira instância, pelas células hepáticas / Abstract: The origin of the albumin in the male reproductive tract has been questioned over the years and their presence tissue constantly assigned to a mechanism for extravasation of plasma into the interstitial extravascular space, assigning the role of the liver as the site of synthesis of this protein in the postnatal period. The distribution pattern of the albumin protein in the epithelial tissues of organs of the male reproductive tract reserves inquiries as to the veracity of their luminal reach through the disruption of their tissue blood-barriers. Carrier steroids; stimulator of Leydig cells; mediator of paracrine mechanism of communication between Sertoli and germ cells; promoter of cell proliferation and mediator of structural changes in cell membranes, with alleged involvement in the acrosome reaction and capacitation of sperm are possible roles of albumin in the male reproductive tract. The association of the albumin protein to glycidyl components is unusual for mammals, but there is support to this hypothesis by the PES (prealbumins epididymis-specific glycoproteins of sheep) and data from our research group through the epitope recognized by the monoclonal antibody (mAb) TRA 54 (testicular germ cells immunized to rat). This dissertation takes up the controversial discussion centered on the presence, source, location and function of albumin in the male reproductive tract and proposed, through a chronological postnatal approach (neonatal, prepubertal, puberal, adult and elderly periods) to revisit the theoretical foundations associated with major serum protein of mammals as well as the dubious expression profile of this protein in Nagase analbuminemic rats (NAR). In this study, the presence of albumin protein was detected by immunoblotting in all groups and periods of postnatal development, with distinct banding pattern in testis and epididymis of NAR. The cellular localization of the albumin protein has been identified in mice by immunohistochemistry mainly in the interstitial tissue and in germline cells. Testes of Sprague Dawley rats showed additional labeling of Sertoli cells. Testes and epididymides of NAR maintained interstitial reactivity, suggesting the expression of albumin even at extremely low levels. To epididymis a broad spectrum of immunostaining of epithelial cells and stereocilia profiles were identified. Vas deferens showed cytoplasmic immunostaining in the region proximal to epididymis, and in the distal region, stereocilia and luminal spermatozoa labeling. Cytoplasmic immunostaining profiles were also observed in the seminal vesicle, prostate and penile urethra, especially in adult period. Finally, the presence of mRNA transcripts detected by RT PCR (reverse transcriptase polymerase chain reaction) assays to testis and epididymis was confirmed from neonates to the elderly, being also present in vas deferens from puberty. The approach of postnatal development revealed a peak with the highest expression of albumin in the adult period beginning to decline at elderly. As a final caveat, the presence of mRNA confirmed for organs of the male reproductive tract does not invalidate the hypothesis of the also presence of circulating albumin in reproductive tissue, which must be synthesized at first instance, by liver cells / Mestrado / Biologia Tecidual / Mestra em Biologia Celular e Estrutural
253

FORMAÇÃO DE PRODUTOS PROTEICOS DE OXIDAÇÃO AVANÇADA A PARTIR DA REAÇÃO DE FENTON E COLÁGENO: EFEITOS SOBRE PROCESSOS INFLAMATÓRIOS EM NEUTRÓFILOS E CÉLULAS RENAIS EMBRIONÁRIAS / ADVANCED OXIDATION PROTEIN PRODUCTS FORMATION THROUGH THE FENTON REACTION AND COLLAGEN: EFFECTS ON INFLAMMATORY PROCESSES IN NEUTROPHILS AND EMBRYONIC KIDNEY CELLS

Bochi, Guilherme Vargas 05 July 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The advanced oxidation protein products (AOPPs) are a new class of compounds identified as markers of oxidative damage to proteins. The physiology role of these products is not limited to assess the oxidative stress, and these products may actively participate in the inflammatory process, promoting different cell disorders, including induction of apoptosis and alterations in the processes of cell proliferation and differentiation. Myeloperoxidase (MPO)-derived hypochlorous acid (HOCl) produced by activated neutrophils contribute significantly to AOPP formation, and human serum albumin (HSA) is considered the main protein responsible for the generation of AOPPs However, the molecular composition of AOPPs is unclear. Additional pathways and protein targets for AOPP formation are largely unknown. The aim of this study was to induce the formation of AOPPs in vitro through Fenton reaction and to investigate whether this generation could be counteracted by N-acetylcysteine (NAC) and fructose-1,6-bisphosphate (FBP). In addition, this study aimed to examine whether AOPPs produced by Fenton reaction may induce the activation of the gene transcription of inflammatory molecules, including the nuclear factor-κB (NF-κB), cyclooxygenase-2 (COX-2) and interleukin-6 (IL-6) in human embryonic kidney cells (HEK 293). Additionally, it was investigated the collagen as a potential source of AOPPs via its exposure to HOCl. The HOCl-modified collagen stimulated the production of oxidants, such as HOCl and superoxide anion radical (O2 -), and pro-inflammatory agents, such as nitric oxide (NO) and AOPPs in human neutrophil. Furthermore, HOCl-modified collagen induced a decrease in cell viability and an increase of apoptosis in these cells. Finally, alpha-tocopherol inhibited the release of oxidants, decreased cell viability and apoptosis, suggesting a therapeutic potential means to prevent deleterious effects caused by AOPPs. Furthermore, these findings indicate that alternative pathways can form AOPPs, and these new products may contribute to the pathogenesis of several clinical conditions related to the accumulation of AOPPs. / Os produtos proteicos de oxidação avançada (AOPPs) são uma nova classe de compostos formados em consequência do estresse oxidativo e considerados biomarcadores úteis na detecção de dano oxidativo proteico. No entanto, o papel desses produtos não se limita apenas a refletir o grau oxidativo de proteínas, mas também podem participar de forma ativa no processo inflamatório, promovendo diferentes perturbações celulares, incluindo a indução de apoptose e alterações nos processos de proliferação e diferenciação celular. O principal mecanismo de formação dos AOPPs é através do ácido hipocloroso (HOCl) produzido pela enzima mieloperoxidase (MPO), sendo a albumina, a principal fonte proteica para a formação desses produtos. No entanto, a via MPO/HOCl parece não ser a única responsável pela formação de AOPPs, e uma série de estudos indicam que há vias alternativas que podem contribuir para formação de AOPPs. Outro fator importante, que também não está totalmente esclarecido, é se a albumina é a única proteína suscetível a formação dos AOPPs, uma vez que a composição molecular desses produtos ainda não está totalmente definida. Além dessas questões, é de interesse avaliar se os AOPPs formados por outra via mantém as características pró-infamatórias e pró-apoptóticas dos AOPPs originados pela via MPO/HOCl. Assim, o presente estudo teve como objetivo investigar se a reação de Fenton, importante geradora de radicais hidroxilas (OH ), é uma potencial via de formação de AOPPs, bem como se o colágeno, principal proteína da matriz extracelular, é uma proteína suscetível a formação desses produtos. Em um primeiro momento, foi demonstrado que a reação de Fenton induziu a formação de AOPPs e esse processo foi inibido por agentes antioxidantes, como N-acetilcisteína (NAC) e frutose-1,6-bisfosfato (FBP). Além disso, os AOPPs gerados através da reação de Fenton induziram um aumento da transcrição gênica de agentes envolvidos no processo inflamatório, incluindo o fator de transcrição κB (NF-κB), a cicloxigenase-2 (COX-2) e a interleucina-6 (IL-6), em células renais embrionárias (HEK 293) através de ensaio de transfecção celular e atividade da Luciferase. Outro importante achado deste estudo foi demonstrar que o colágeno exposto ao HOCl também é uma fonte proteica para a formação de AOPPs. Os AOPPs formados a partir do colágeno estimularam a produção de oxidantes, como o HOCl e radical ânion superóxido (O2 -), e de agentes inflamatórios, como óxido nítrico (NO) e AOPPs, em neutrófilos humanos isolados. Além disso, os AOPPs derivados do colágeno induziram uma diminuição da viabilidade celular e um aumento do processo apoptótico nessas células. Por fim, o alfa-tocoferol inibiu a liberação de oxidantes, preveniu a diminuição da viabilidade celular e o aumento do processo apoptótico, sugerindo que esse composto pode ser uma potencial ferramenta terapêutica para prevenir os efeitos deletérios promovidos pelos AOPPs. Do mesmo modo, esses achados indicam que os AOPPs podem ser formados por vias alternativas, e esses novos produtos podem contribuir na fisiopatogênese de diversas condições clínicas relacionadas com o acúmulo de AOPPs.
254

Development of ADAPT-based tracers for radionuclide molecular imaging of cancer

Garousi, Javad January 2017 (has links)
ABD-Derived Affinity Proteins (ADAPTs) is a novel class of small engineered scaffold proteins based on albumin-binding domain (ABD) of streptococcal protein G. High affinity ADAPT  binders against various therapeutic targets can be selected.  In this thesis, we report a development of ADAPT-based radionuclide imaging agents providing high sensitivity and specificity of molecular imaging of HER2 expression in disseminated cancers. We investigated the feasibility of the use of ADAPTs as imaging agents and influence of molecular design and radiolabeling chemistry on in vivo targeting and biodistribution properties of the tracers. In Paper I we demonstrated the feasibility of the use of anti-HER2 ADAPT6 molecule as a high contrast imaging agent; In Paper II we evaluated the influence of composition of histidine-containing tag on in vivo biodistribution of ADAPT-based tracers labeled with 99mTc using 99mTc(CO)3 binding to histidine-containing tags and 111In using DOTA chelator at N-terminus; In Paper III we evaluated the influence of different aspects of N-terminus leading sequence on targeting including effect of sequence size on clearance rate and effect of the composition of the sequence on biodistribution profile; In Paper IV, we evaluated the influence of residualizing properties and positioning of the label on biodistribution and targeting; and In Paper V, we compared tumor-targeting properties of the ADAPT6 labeled at C-terminus with 99mTc using N3S chelator and 111In using DOTA chelator. In conclusion, ADAPTs constitute a very promising class of targeting probes for molecular imaging providing high contrast. Molecular design of the ADAPT proteins and chelators/linkers for labeling has an appreciable effect on their imaging properties.
255

Micro-injection moulded microneedles for drug delivery

Nair, Karthik Jayan January 2014 (has links)
The emergence of microneedle (MN) technologies offers a route for a pain free, straightforward and efficient way of transdermal drug delivery, but technological barriers still exist which pose significant challenges for manufacture of MN systems with high volume outputs at low cost. The main aim of this research was to develop new ways for MN manufacture primarily using micro-injection moulding processes with high performance engineering thermoplastics. During the moulding process these polymeric melts will be subjected to extreme stress and temperature gradients and detailed material characterisation combined with in-line monitoring is desirable to optimise the moulding parameters and will help in achieving sharp microneedles with acceptable quality. Hence high shear rheology of these selected materials was performed at wall shear rates carried out in excess of 107 s-1 over a range of temperatures to predict the flow behaviour of polymer melts at such high shear strain rates. This information was fed into injection moulding simulation software tools (Moldflow) to assist the MN production process design. The optimal design was then used to produce a full 3D solid model of the injection mould and mould insert. Furthermore various design of experiments were conducted considering input parameters such as injection pressure, injection speed, melt temperature, filling time and mould cavity temperature. Response variables including product quality and data acquired from the cavity pressure and temperature transducers were used to optimise the manufacturing process. The moulded MNs were geometrically assessed using a range of characterisation techniques such as atomic force microscopy, confocal microscopy and scanning electron microscopy. An attempt to make hollow MNs was performed and encountered many challenges like partial cavity filling and part ejection during processing. Studies were carried out to understand the problem and identified the major problem was in tool design and improvements to the moulding tool design were recommended. Plasma treatment and mechanical abrasion were employed to increase the surface energy of the moulded polymer surfaces with the aim of enhancing protein adsorption. Sample surface structures before and after treatment were studied using AFM and surface energies have been obtained using contact angle measurement and calculated using Owens-Wendt theory. Adsorption performance of bovine serum albumin and release kinetics for each sample set was assessed using a Franz diffusion cell. Results indicate that plasma treatment significantly increases the surface energy and roughness resulting in better adsorption and release of BSA. To assist design-optimisation and to assess performance, a greater understanding of MN penetration behaviour is required. Contact stiffness, failure strength and creep behaviour were measured during compression tests of MN against a steel surface, and in-vitro penetration of MNs into porcine skin. The MN penetration process into porcine skin was imaged using optical coherence tomography. Finally, a finite element model of skin was established to understand the effect of tip geometry on penetration. The output of findings from this research will provide proof of concept level development and understanding of mechanisms of MN penetration and failure, facilitating design improvements for micro-injection moulded polymeric MNs.
256

Stress oxydant et pathologie diabétique à l’île de La Réunion – Identification et caractérisation des propriétés structurales et fonctionnelles de l’albumine glyquée / Oxidant stress and diabetes – Deciphering structural and functional impacts of glycoxidation on human albumin

Baraka-Vidot, Marie-Jennifer 03 December 2014 (has links)
La glycoxydation est un processus délétère directement impliqué dans la pathologie diabétique. Ce phénomène touche principalement les protéines circulantes. Une des cibles majoritaires de ce phénomène est l'albumine, protéine plasmatique la plus abondante. L'objectif de ce travail de thèse vise une meilleure compréhension du phénomène de glycoxydation dans le diabète. Pour cela, les conséquences fonctionnelles et physiologiques liées aux altérations structurales et biochimiques de l'albumine glyquée ont été étudiées, à travers la comparaison d'un modèle d'albumine glyquée in vivo purifiée de patients diabétiques avec celui correspondant à la protéine glyquée par un processus in vitro. Notre étude montre des modifications de type structural et oxydatif attestées par des mesures de fluorescence (accessibilité du tryptophane) et de groupements spécifiques comme les fructosamines, les amines primaires, résidus thiols et carbonyles. D'un point de vue fonctionnel, l'albumine glyquée purifiée de patients diabétiques exerce, sur des cultures cellulaire, un effet proinflammatoire et prooxydant, encore plus marqué que ne le fait l'albumine glyquée in vitro. Également, les capacités de liaison de l'albumine avec les médicaments ainsi que l'activité estérase diminuent avec le phénomène de glycation. Les résultats de cette étude apportent de nouveaux éléments de compréhension sur le phénomène de glycation de l'albumine tel qui pourrait apparaitre dans la pathologie diabétique et ouvre de nouvelles pistes d'études sur l'impact réel des AGEs issus de l'albumine dans des désordres physiologiques inhérents à cette pathologie. / Albumin constitutes the major circulating protein in blood and represents a very beneficial biological actor through its multifunctional properties such as antioxidant activities and drug binding capacities. But, in hyperglycemic conditions, such as those encountered in diabetes, albumin can undergo glycoxidative modifications which may impact the protein quality. Objectives of my thesis were to clarify the impact of glycoxidative modification of albumin on its structure and its functions and to determine whether such impairments may be encountered in albumin purified from diabetics. The occurrence of structural and oxidative modifications were found to be enhanced in in vitro glycoxidized HSA and albumin purified from diabetics, after determination of their free thiol group content, relative electrophoretic migration, carbonyl content, fructosamines and antioxidant activities. In addition, glycoxidized albumins exhibited impaired pharmaceutic molecule binding capacities and reduced esterase activities. Also, cells treated with glycoxidized albumin purified from diabetics, exhibited a proinflammatory state even more exacerbated than those incubated with in vitro glycated albumins. We evidenced the triggering action of metals (copper and iron) on glycoxidative-induced modifications in albumin. This work needs further studies and opens doors to many perspectives aiming to reach a better understanding of glycoxidative modification of albumin in diabetic patients.
257

Adipocinas, excreção urinária de albumina, sensibilidade insulínica e função da célula beta na deficiência isolada do hormônio de crescimento / ADIPOKINES, URINARY ALBUMIN EXCRETION, INSULIN SENSITIVITY AND BETA CELL FUNCTION IN ISOLATED GROWTH HORMONE DEFICIENCY.

Oliveira, Carla Raquel Pereira 29 November 2010 (has links)
The aim of this study was to assess the dissociation between the presence of cardiovascular risk factors, and the lack of premature atherosclerosis and left venticular hipertrophy (LVH) in isolated GH deficiency (IGHD) due to a mutation in the GH releasing hormone receptor gene. A two step protocol was performed. In the first experiment, serum adiponectin and leptin, and urinary albumin excretion (UAE) were studied in 20 IGHD individuals (7 M/ 13 F; 50,8 ± 14,6 years) and 22 control subjects (C) (8 M/ 14 F; 49,9 ± 11.5 years). IGHD subjects in comparison to C presents high adiponectin levels (p= 0,041) whereas leptin and UAE were similar. In the second experiment, oral glucose tolerance test (1,75 g/Kg in IGHD and 75 g in C) with glucose and insulin mesuarements at 0, 30, 60, 90, 120 e 180 minutes was performed in 24 IGHD subjects (12 M/ 12 F; 39,25 ± 11,73 years) and 25 C subjects (14 M/ 11 F; 39,96 ± 12,49 years). Insulin sensitivity (IS) was assessed by HOMAir, lower values, higher IS; QUICKI, OGIS 2 and OGIS, higher values, higher IS (for the three parameters). Beta cell function was assayed by HOMA-beta, insulinogenic index and area under the curve of the relation between insulin and glucose (AUC I/G). ANOVA indicated glucose response was higher (p<0,0001) and insulin response presented a trend of reduction (p=0,08) in the IGHD gruop. The number of pacients with glucose intolerance was higher (p= 0,001) in the IGHD group. HOMAir was lower (p= 0,041), QUICKI and OGIS 2 showed a trend of elevation (p= 0,066 and p= 0,09, respectively) in the IGHD subjects, whereas OGIS 3 showed no difference between both groups. IGDH presented reduction in HOMA-beta (p= 0,015), insulinogenic index (p<0,0001) and AUC I/G (p=0,02). These different adipokine profile with high adiponectin and normal leptin levels, linked to normal insulin sentitivity may delay vascular damage, LVH and lesions of the renal endothelium (normal UAE). Normal IS and reduced beta cell function featured this IGDH model. / O objetivo deste trabalho foi aprofundar a avaliação da dissociação entre a presença de marcadores de risco cardiovascular (CV) e a ausência de doença CV (DCV) na deficiência isolada do GH (DIGH) por mutação no gene do receptor do hormônio liberador do GH. Foi realizado um protocolo com duas etapas. No primeiro experimento, foram avaliados os níveis séricos de adiponectina e leptina e a excreção urinária de albumina (EUA) em 20 indivíduos com DIGH (7 M/ 13 F; 50,8 ± 14,6 anos) e 22 controles (C) (8 M/ 14 F; 49,9 ± 11.5 anos). Os indivíduos com DIGH em comparação a C apresentaram adiponectina mais elevada (p= 0,041) sem alteração nos níveis de leptina e EUA. No segundo experimento, foi realizado teste de tolerância à glicose oral de glicose (1,75 g/kg no DIGH e 75 g no C) com dosagens de glicose e insulina nos tempos 0, 30, 60, 90, 120 e 180 minutos em 24 indivíduos DIGH (12 M/ 12 F; 39,25 ± 11,73 anos) e 25 C (14 M/ 11 F; 39,96 ± 12,49 anos). A sensibilidade à insulina (SI) foi avaliada pelo HOMAir, onde menores valores, indicam maior SI; e pelos QUICKI, OGIS 2 e OGIS 3, onde maiores valores, indicam maior SI. A função da célula beta foi avaliada pelo HOMA-beta, índice insulinogênico e área sobre a curva da razão insulina/ glicose (ASC I/G). ANOVA indicou que a resposta glicêmica (p< 0,0001) foi maior e a insulinêmica apresentou uma tendência de redução (p= 0,08) no grupo DIGH. O número de pacientes com intolerância à glicose foi maior (p= 0,001) no grupo DIGH. HOMAir foi mais baixo (p= 0,031), e QUICK e OGIS 2 apresentaram uma tendência de elevação (p= 0,066 e p= 0,09, respectivamente) no grupo DIGH, enquanto o OGIS 3 foi semelhante nos dois grupos. DIGH apresentou HOMA-beta (p= 0,015), índice insulinogênico (p< 0,0001) e ASC I/G (p= 0,02) menores. O perfil de adipocinas caracterizado por adiponectina elevada e leptina normal, associado à SI normal pode retardar DCV e disfunção endotelial (EUA normal). SI normal e menor função da célula beta caracterizam este modelo de DIGH.
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Improving Caco-2 cell permeability assay using phospholipid covered silica beads

Faradj, Lana January 2021 (has links)
The Caco-2 cell assay is widely used for in vitro permeability measurements. However, a draw back with the assay that this study will focus on improving, is compound adsorption to the plastic material. Lipophilic compounds such as Cyclosporin A and Peptide J, that will be used in this study, tend to bind to the plastic material in the assay. This can result in poor recovery and misleading permeability predictions. Bovine serum albumin (BSA) is an alternative used today to prevent this but is not always successful.    The aim of this study is therefore to improve the Caco-2 permeability assay by adding phospholipid covered silica beads (PLB) to the basolateral chamber. The role of the PLB is to bind the compound of interest and decrease the amount of compound bound to the plastic material and thus better predict the permeability of the compound of interest.   The PLB was produced using phosphatidylcholine and silica beads. Caco-2 cells were seeded and maintained for 21-29 days ahead of the experiment. PLB concentration of 20, 60 and 100 mg/ml were prepared. Samples were analyzed with HPLC-MSMS. The results showed that with increasing PLB concentration we had a significantly decrease in non-specific plastic binding resulting in reliable permeability predictions, concluding that the hypothesis was correct.
259

Analýza mazání TEP kyčle s využitím fluorescenční mikroskopie / Analysis of THR lubrication with the use of fluorescent microscopy

Tkadlec, Tadeáš January 2018 (has links)
This diploma thesis deals with an experimental analysis of lubrication of total hip joint replacement using fluorescence microscopy, focusing on so-called soft bearing pairs. Experiments were realized using a hip joint simulator, which was modified and refined for fluorescence microscopy. The aim of this diploma thesis was to determine the effect of the individual components of the synovial fluid on the lubrication mechanisms. For this purpose, different model fluids were designed to represent the composition of proteins and other synovial fluid constituents to elucidate the effect of albumin, -globulin and hyaluronic acid on the resulting lubrication performance. The experiments were separate into two categories different in type of load, dynamic (representative walking) and combined (representing standing with short walk). The experimental results were time-dependent fluorescence intensity values, representing dimensionless film thickness parameters. The values were recorded on the graphs and supplemented with fluorescence images taken during the characteristic sections of the measurements. The measured data was subsequently confronted with previously published articles. It was found that the dominant constituent responsible form film thickness is albumin, while -globulin and hyaluronic acid forms thin stable layer enhancing adsorption ability of albumin which contributes to increase of film thickness eventually.
260

Studium mazání náhrady kolenního kloubu / An investigation of lubrication of knee joint replacement

Sýkora, Tomáš January 2020 (has links)
This diploma thesis deals with an experimental analysis of knee joint replacement lubrication. The experiments were realized at a knee joint simulator which can apply conditions according to certain standard and survey the phenomena by using fluorescence microscopy. The aim of thesis is to clarify the influence of particular components of synovial fluid on the lubrication process. The intensity of fluorescence expresses dimensionless parameter of a lubrication film thickness. There was a fundamental study with mineral oils before the experiments with the synovial fluid. The study allows to have a look at contact transformation during walk. Results are shown in graphs as dependency of intensity on time, including pictures showing phenomena in the contact zone. Experiment results show that protein -globulin creates a layer on the surface. There is albumin on the layer and it makes the lubricating film thicker. The protein interaction is supported by hyaluronic acid and fosfolipids which stabilizes the created structure. According to lubrication is behaviour of film related to a complex structure of synovial fluid. Thesis gives more information about behaviour of synovial fluid and can be used for future development of knee replacements.

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