Embora a literatura tenha sugerido que o nível de ácido úrico (AU) está associado com hipertensão arterial (HAS) e a síndrome metabólica( SM), esta relação ainda permanece incerta. O objetivo deste trabalho foi estudar em uma população brasileira não-hospitalar, a associação entre o AU, a HAS, a SM e variáveis de risco cardiovascular. Este é um estudo transversal realizado em 1005 indivíduos de ambos os gêneros com idade variando entre 20 a 96 anos, que se submeteram a uma avaliação clínica rotineira, onde a pressão arterial (PA), o índice de massa corporal( IMC), a circunferência abdominal( CA), o colesterol total, o HDL-C, os triglicerídeos, a glicose, a uréia, a creatinina e o AU foram medidos. A população foi estratificada por quintis de AU de acordo com o sexo, a saber: &#8804; 4,6 mg/dl, > 4,6 e 5,4mg/dl, > 5,4 e 6,0 mg/dl, > 6,0 e 6,8mg/dl e > 6,8mg/dl para os homens. Para o gênero feminino foram encontrados &#8804; 3,2 mg/dl, > 3,2 e 3,9 mg/dl, > 3,9 e 4,5 mg/dl, > 4,5 e 5,3 md/dl e > 5,3 mg/dl. Não havia diferença significativa quanto ao gênero e a idade (c2 = 1,634; p=0,950). A idade média da população era 50,97 ( 17,35) sendo 51,8% de homens. A prevalência da HAS era de 48,9%, 30,1% de sobrepeso/obesidade ( S/O) e 30,5% de SM. Os maiores quintis de AU mostraram maiores prevalência s de HAS, SM S/O, hiperglicemia e alto risco cardiovascular pelo escore de Framingham (P<0,0001). A analise univariada mostrou uma relação positiva e significativa entre o AU, PAS, PAD, IMC, CA, triglicerídeos e creatinina e negativa e significativa com o HDL-c ( p<0,0001). Na análise multivariada o AU permaneceu associado de maneira independente tanto para a SM OR=1,164, CI 1,014-1,335, p=0,038) quanto para a HAS OR=1,206, CI 1,083-1,342, p=0,006), após o ajuste para as clássicas variáveis cardiovascular. Em conclusão o presente estudo demonstra que o ácido úrico se associou de maneira independente as variáveis de risco cardiovascular. / Although several studies have suggested that uric acid (UA) level is associated with hypertension and metabolic syndrome (MS), this relationship remains uncertain. The aim of this study was to investigate in a non-hospitalized Brazilian population, the association between UA and blood pressure, MS and various risk factors. This was a cross-sectional data from 1005 individuals aged 20 to 96 years who underwent general health screening. Blood pressure, body mass index (BMI), abdominal circumference (AC) , total and HDL cholesterol, serum triglycerides, creatinine, glucose and serum uric acid were measured. The population was subdivided according sex-specific quintiles of serum UA, which were &#8804; 4.6 mg/dl, > 4.6 and &#61603; 5.4mg/dl, > 5.4 and &#61603; 6.0 mg/dl, > 6.0 and &#61603; 6.8mg/dl and &#8805; 6.8mg/dl in men. For women we found &#8804; 3.2mg/dl, > 3.2 and &#61603; 3.9mg/dl, > 3.9 and &#61603; 4.5mg/dl, > 4.5 and &#61603; 5.3md/dl and &#8805; 5.3mg/dl. Population was similarly distributed by gender and 10 year-age groups (&#61539;2 = 1.634; p=0.950). At baseline, the mean age was 50.97 ( 17.35) years with 51.8% of men. The prevalence of hypertension in the whole population was 48.9%, 60.1% for overweight/obesity and 30.5% for MS. The fifth UA quintile showed higher prevalences of hypertension, MS, overweight/obesity, hyperglicemia, and high cardiovascular risk individuals estimated by Framingham escore (p<0.0001). Univariate analysis showed a positive correlation between UA and systolic and diastolic BP, BMI, AC, triglycerides and creatinine and a negative correlation with HDL-c (p<0.0001). In multivariate analysis, uric acid remained associated with MS (OR=1.164, CI 1.014-1.335, p=0.038), and with hypertension (OR=1.206, CI 1.083-1.342, p=0.006), after adjusting for classic cardiovascular risk factors. In conclusion, our data indicate that uric acid is independently associated with cardiovascular risk variables.

Orientador: Marilda Mazzali / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-14T09:11:43Z (GMT). No. of bitstreams: 1 Nicolielo_RenatoLuizCursino_M.pdf: 2896438 bytes, checksum: 3df4ea3bde6ce115708b78e7b010be98 (MD5) Previous issue date: 2009 / Resumo: Hiperuricemia é associada ao desenvolvimento de remodelamento vascular e hipertensão arterial em modelos experimentais. Por outro lado, o uso de agentes redutores dos níveis de ácido úrico (hipouricemiantes) proporciona a normalização pressórica e proteção contra o desenvolvimento de doença renal. Objetivo: Determinar o efeito de agentes hipouricemiantes sobre a pressão arterial de animais SHR. Métodos: ratos machos SHR e WKY, com 4 semanas de idade, acompanhados durante 9 semanas. Os animais SHR foram tratados com alopurinol (SHRALP) ou benzbromarona (SHRBENZ). Pressão arterial de cauda, função renal e histologia renal foram comparados aos animais SHR não tratados (SHRCT) e aos controles normotensos WKY (WKYCT). Pressão arterial de cauda foi medida no período inicial e semanalmente até o sacrifício. Resultados: Tratamento com agentes hipouricemiantes reduziu a PA em animais SHR, com melhor controle no grupo SHRALP (SHRCT 214±7,7; SHRALP 164±3,5; SHRBENZ 179±2,3 mmHg, p<0,05). O tratamento foi associado com redução significativa dos níveis de ácido úrico comparado aos controles SHR (SHRCT 1,6±0,6; SHRALP 0,9±0,2*; SHRBENZ 1,0±0,4* mg/dl, *p<0.05). A função renal permaneceu inalterada em todos os grupos durante o acompanhamento. Análise histológica dos fragmentos renais mostrou redução significativa do percentual de arteríolas pré-glomerulares remodeladas nos animais tratados, em comparação aos controles SHR (84,3±8,5%SHRCT; 66,4±20,1%SHRALP*; 71,6±15,3% SHRBENZ* p<0,05). Espessamento de arteríolas pré-glomerulares, quantificada por método de captura de imagem computadorizada mostrou redução significativa da área de parede arteriolar nos animais tratados em comparação aos SHR não tratados (SHRCT). A espessura arteriolar do grupo SHRALP foi compatível a dos animais controles WKY. Conclusão: O uso de agentes hipouricemiantes foi associado com redução de PA e de remodelamento vascular de arteríolas préglomerulares em animais SHR. Como esses animais já apresentam nível sérico de ácido úrico mais elevado que os WKY com 4 semanas de vida, apesar de níveis pressóricos normais, intervenção em idades mais precoces talvez possa prevenir o desenvolvimento de hipertensão arterial e remodelamento vascular nestes animais. / Abstract: Hyperuricemia is associated with vascular remodeling and hypertension in experimental models, and use of uric acid (UA) lowering agents is associated with BP normalization and protection of renal disease. Aim: To determine the effect of UA lowering agents on BP in SHR animals. Methods: Male SHR and WKY rats, 4 weeks old, were followed for 9 weeks. SHR animals received allopurinol (SHRALP) or benzbromarone (SHRBENZ) and BP, renal function, and renal histology were compared to untreated SHR (SHRCT) and WKY controls (WKYCT). Blood pressure was measured at baseline and every week until sacrifice. Results: Treatment with UA lowering agents reduced BP in SHR, with better control in SHRALP group (SHRCT 214±7.7, SHRALP 164±3.5, SHRBENZ 179±2.3 mmHg, p<0.05). Treatment was associated with a significant reduction in serum UA levels compared to SHRCT (SHRCT 1.6±0.6, SHRALP 0.9±0.2*, SHRBENZ 1.0±0.4* mg/dl, *p<0.05). Renal function remained unchanged in all groups. Histological analysis showed a significant reduction in vascular remodeling in SHR treated with UA-lowering agents compared to SHRCT (84.3±8.5%SHRCT, 66.4±20.1%SHRALP*, 71.6±15.3% SHRBENZ* p<0.05). Pre-glomerular arterial thickness, measured by computer assisted analysis, showed a reduction in arteriolar wall area in SHR treated compared to SHRCT. Arteriolar thickness in SHRALP group was comparable to WKYCT. Conclusion: The use of UA lowering agents was associated with a reduction in BP and pre glomerular arteriolopathy in SHR. As SHR rats already had higher UA than WKY controls at 4 weeks of life, despite normal BP, an earlier intervention might prevent the development of hypertension and vascular remodeling in these animals. / Mestrado / Ciencias Basicas / Mestre em Clinica Medica

Orientador: Marilda Mazzali / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-08T15:27:17Z (GMT). No. of bitstreams: 1 Mazali_FernandaCristina_M.pdf: 3384913 bytes, checksum: 0d3a47a884265f3d5949b9aff82161a6 (MD5) Previous issue date: 2006 / Resumo: Objetivo: Hiperuricemia é uma complicação freqüente da terapêutica com ciclosporina (CsA). Estudos anteriores demonstraram que a hiperuricemia exacerba a lesão intersticial e vascular no modelo experimental de nefrotoxicidade por CsA (CsA ntx). O presente estudo tem como hipótese que a normalização da uricemia preveniria o desenvolvimento da nefropatia crônica por CsA. Metodologia: A nefropatia crônica por CsA foi induzida em ratos machos, Sprague Dawley, através da injeção subcutânea diária de CsA (15mg/kg/dia), por um período de 7 semanas, em associação com dieta hipossódica (CSA). O efeito do controle da hiperuricemia foi determinado através do tratamento concomitante com um inibidor de xantina oxidase (alopurinol, 15mg/Kg/dia ? CSA/ALP) ou com um agente uricosúrico (benzbromarona, 15mg/Kg/dia, CSA/BENZ), em bebedouro. O grupo-controle incluiu ratos tratados com veículo (VEH, injeções SC diárias de óleo de oliva). Ao sacrifício foram realizadas análises funcionais e histológicas. Resultados: Os animais do grupo CSA desenvolveram hiperuricemia leve (ácido úrico 4.36 vs 2.49 mg/dl, CSA vs VEH, p<0.05), com hialinose arteriolar, atrofia tubular, fibrose intersticial em faixa, aumento de proliferação celular e redução da expressão de VEGF. O tratamento com alopurinol ou benzbromarona reduziu a lesão renal, assim como os níveis de ácido úrico e creatinina sérica (ácido úrico 2.03 CSA/ALP e 2.93 mg/dl, CSA/BENZ, p<0.05 vs VEH e CSA). Ambos os tratamentos reduziram a fibrose intersticial, a proliferação celular, infiltrado de macrófagos, expressão de osteopontina e hialinose arteriolar, em associação com restauro da expressão de VEGF, com proteção comparável entre as duas drogas. Conclusão: A hiperuricemia exacerba a nefropatia pela CsA em ratos. Tratamento concomitante com alopurinol ou benzbromarone reduz a severidade da lesão. Como ambas as drogas promovem proteção semelhante, concluímos que o efeito protetor é associado ao controle da hiperuricemia, mais importante que o efeito antioxidante do alopurinol / Abstract: Aim: Hyperuricemia frequently complicates cyclosporine (CSA) therapy. Previous studies have shown that hyperuricemia increases the interstitial and vascular lesions in the cyclosporine model. We therefore tested the hypothesis that normalization of uric acid could prevent the development of cyclosporine toxicity. Material and Methods: CSA nephropathy was induced by the administration of CSA (15 mg/kg/day) for 7 weeks to rats on a low salt diet (CSA group). The effect of preventing hyperuricemia on CSA nephropathy was determined by concomitant treatment with the xanthine oxidase inhibitor, allopurinol (CSA-ALP), or with the uricosuric, benzbromarone (CSA-BENZ), in the drinking water. Control groups included rats treated with vehicle (VEH). Histological and functional studies were determined at sacrifice. Results:. CSA treated rats developed mild hyperuricemia with arteriolar hyalinosis, tubular atrophy, striped interstitial fibrosis, increased cell proliferation and decreased VEGF expression. Treatment with either allopurinol (CSA-ALP) or benzbromarone (CSA-BENZ) reduced renal injury. Both treatments reduced interstitial fibrosis, cell proliferation, macrophage infiltration, osteopontin expression and arteriolar hyalinosis in association with restoration of VEGF expression. Both drugs provided comparable protection. Conclusions: An increase in uric acid exacerbates CSA nephropathy in the rat. Concomitant treatment with allopurinol or benzbromarone reduced the severity of renal disease. As both drugs promoted similar protection, we can conclude that the protective effect is associated with lowering uric acid levels, more than the antioxidant effect of allopurinol / Mestrado / Ciencias Basicas / Mestre em Clinica Medica

FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Com a finalidade do desenvolvimento de novos nanodispositivos, hà um grande interesse em conhecer as propriedades eletrÃnicas de materias nanoestruturados. Sobretudo, como modificar as propriedades eletrÃnicas de nanoestruturas jà bem conhecidas de forma controlada. Com este objetivo, muitas metodologias e experimentos tem sido desenvolvidos. Neste trabalho, estudamos de forma inteiramente atomÃstica atravÃs de simulaÃÃo computacional as propriedades eletrÃnicas, Ãpticas e vibracionais de (a) pontos quÃnticos esferÃricos maciÃos e ocos de silÃcio, (b) nanoflocos de grafeno e (c) cristais de Ãcido Ãrico anidro, mono e dihidratado utilizando mÃtodos de DinÃmia Molecular, SemiempÃrico, DFTB+ e DFT, para tanto utilizamos o programa AMPAC e os mÃdulos do Materials Studio (Accelrys), o Forcite, CASTEP, Gulp e o Dmol3 que sÃo estados de arte em simulaÃÃes atomÃsticas. Do ponto de vista clÃssico utilizamos campos de forÃa Brenner, que permite a formaÃÃo e rompimento de ligaÃÃes covalentes; do ponto de vista quÃntico, utilizamos o mÃtodo do funcional da densidade e DFTB+ . No estudo dos pontos quÃnticos silÃcio obteve-se uma diminuiÃÃo do gap de energia em funÃÃo do aumento do raio para os pontos maciÃos, e comportamento contrÃrio para os pontos ocos, quando fixamos um ponto e variamos tÃo somente o raio do buraco. Para os nanoflocos de grafeno obteve-se por meio de DinÃmica Molecular a estabilidade das estruturas, averiguando que atà 1000K elas conservam sua forma plana; acima de 3400K as estruturas comeÃam a ter suas ligaÃÃes rompidas. Os gaps de energia HOMO-LUMO sÃo sensÃveis Ãs bordas. A anÃlise dos estados de spins revelou que somente os nanoflocos triangulares com borda zigzag possuem excesso de elÃtrons com spin alfa, dependente no entanto da simetria. Os modos de vibraÃÃo para estruturas com nC ~ 50 foram obtidas e observou-se que nanofloco retangular exibe bandas de abosorÃÃo em comum com nanoflocos zigzag em dois intervalos do espectro infravermelho. Finalmente para os cristais de Ãcido Ãrico, observou-se que os parÃmetros de rede para o cristal dihidratado sÃo menos coerentes com valores experiemntais. O gap do cristal de Ãcido Ãrico anidro e mono à direto (~ 3.18 eV e 3.16 eV, respectivamente) e do dihidratado à indireto (~ 2.89 eV). Os orbitais 2p sÃo os maiores contribuintes à densidade de estados. A Ãgua tem bastante influÃncia na banda de conduÃÃo do cristal dihidratado. Hà um comportamento anisotrÃpico quando do estudo das propriedades Ãpticas destes cristais ao longo de quatro direÃÃes de incidÃncia do campo elÃtrico, sendo a anisotropia mais acentuada para o dihidratado. As pesquisas realizadas enquadram-se na temÃtica de atuaÃÃo do Instituto de NanoBioEstruturas & SimulaÃÃoao NanoBioMolecular [NANO(BIO)SIMES], um dos Institutos Nacionais de CiÃncia e Tecnologia financiados pelo CNPq a partir do inÃcio de 2009, que visa desenvolver atividades de pesquisa e formaÃÃo de recursos humanos de alto nÃvel em nanobioestruturas e simulaÃÃo nanobiomolecular / There is a great interest in understanding the electronic properties of nano-structured materials aiming the development of new nano devices, especially how to modify the electronic properties of nano structures already known in a controlled manner. This work shows our studies, which were made in a pure atomistic way by computational simulation, on the electronic, optical and vibrational properties of (a) spherical quantum dots, silicon solid and hollow ones, (b) graphene nanoflakes and (c) crystals of uric acid, anhydrous, mono and dihydrate ones, using methods of Molecular Dynamics, Semiempirical, DFTB+ and DFT. We used the software called AMPAC and the modules of Materials Studio (Accelrys), the Forcite, CASTEP, Gulp and Dmol3 that are states of art in atomistic simulations. From the classical point of view we used Brenner force fields, which allow the formation and breaking of covalent bonds; and from the quantum dots of view, we used the method of density functional and DFTB+. In the study of silicon quantum dots, it was obtained a decrease of the energy gap due to the increase of the radius for massive dots, and contrary behavior to the hollow dots, when we fixed one point and varied only the radius of the hole. In relation to the graphene nanoflakes, it was obtained the stability of structures by the Dynamics Molecular, verifying that they keep their flattened form up to 1000 K; over 3400 K structures begin to have their links broken. The HOMO-LUMO energy gaps are sensitive to edges. Analysis of spin states revealed that only the triangular nanoflakes with zigzag edge have excess of electrons with alpha spin, however symmetry dependent. The modes of vibration for structures with nC ~ 50 were obtained and it was observed that rectangular nanoflake displays absorption bands in common with zigzag nanoflakes in two ranges of the infrared spectrum. Finally for the uric acid crystals, we observed that the lattice parameters for the dihydrate crystal are less consistent with experimental values. The gap of the crystal of uric acid, anhydrous and mono ones, is direct (~ 3.18 eV and 3.16 eV, respectively) and of the dihydrate is indirect (~ 2.89 eV). The 2p orbitals are the largest contributors to the density of states. Water has great influence in the conduction band of the dihydrate crystal. There is an anisotropic behavior in relation to the study of the optical properties of these crystals along four directions of incidence of the electric field, where the anisotropy is more accentuated to the dihydrate. The studies fit in the theme of the role of Instituto de NanoBioEstruturas & SimulaÃÃo NanoBioMolecular [NANO(BIO)SIMES], one of the National Institutes of Science and Technology funded by CNPq from the beginning of 2009, which aims to develop research activities and high-quality human resource training in nanobiostructures and nanobiomolecular simulation

A mecanização de procedimentos analíticos em análises clínicas traz vantagens tais como minimização de erros sistemáticos e do tempo das análises. Sistemas de análises em fluxo com multicomutação apresentam grandes potencialidades nesse sentido, atendendo às necessidades da mecanização de procedimentos analíticos de maneira versátil e robusta. Estes sistemas permitem minimizar o consumo de reagentes e a geração de resíduos, devido ao gerenciamento preciso de pequenos volumes de soluções por dispositivos controlados eletronicamente, tais como microbombas solenoide. O fluxo pulsado proporcionado pelas microbombas e a estratégia da amostragem binária melhoram a mistura entre amostra e reagentes. O ácido úrico é o principal produto final do metabolismo de purinas. A determinação deste analito em amostras de urina apresenta importância clínica, uma vez que sua concentração pode auxiliar no diagnóstico de disfunções no organismo humano, como a gota e o mau funcionamento dos rins. Um procedimento analítico empregando sistema de análises em fluxo com microbombas solenoide foi desenvolvido para a determinação de ácido úrico em amostras de urina. Os íons Cu(II) são reduzidos pelo ácido úrico a íons Cu(I), que podem ser quantificados por espectrofotometria na presença do ácido 4,4\'-dicarboxi-2,2\'- biquinolínico (BQA). Resposta linear foi observada entre 10 e 100 &#181;mol L-1 de ácido úrico, sendo a curva analítica representada pela equação A=(0,0063±0,0002)CAU + (0,0285±0,0040), r = 0,999, em que CAU é a concentração de ácido úrico em &#181;mol L-1. O limite de detecção foi estimado em 3,0 &#181;mol L-1 (99,7% de nível de confiança; n = 20). O coeficiente de variação foi estimado em 1,2% com 20 medidas de uma solução de ácido úrico 75 &#181;mol L-1 e a frequência de amostragem foi de 150 h-1. As principais espécies concomitantes presentes na urina não interferem na determinação de ácido úrico em concentrações até 5 vezes maiores que as usualmente encontradas. Recuperações entre 91 e 112% foram estimadas e os resultados das análises de 4 amostras de urina concordaram com os obtidos pelo procedimento enzimático para a determinação de ácido úrico (95% de nível de confiança). O alto grau de diluição da amostra necessário (100 vezes) minimiza o volume de amostra utilizado e os efeitos de matriz. Uma simples reconfiguração do sistema e a reotimização das frações volumétricas permitiram que a amostra fosse diluída em linha por reamostragem na zona dispersa. Resposta linear foi observada até 5,0 mmol L-1 de ácido úrico, sendo a curva analítica obtida representada pela equação A=(0,105±0,001) CAU + (0,023±0,003), r=0,999, em que CAU é a concentração de ácido úrico em mmol L-1. O coeficiente de variação, o limite de detecção e a frequência de amostragem foram estimados em 1,0%, 0,2 mmol L-1 e 95 h-1, respectivamente. Os resultados da análise de 3 amostras de urina concordaram com os obtidos pelo procedimento enzimático, com nível de confiança de 95% / Mechanization of analytical procedures in clinical analysis brings advantages such as minimization of systematic errors and analysis time. Multicommuted flow systems attain the requirements to mechanization of analytical procedures in a versatile and robust way, minimizing reagent consumption and waste generation, due to the low solution volumes handled by electronically controlled devices, such as solenoid micro-pumps. The pulsed flow characteristic of the micro-pumps and the binary sampling approach improve sample and reagent mixing. Uric acid is the main end product of purine metabolism and its determination in urine shows clinical importance, because its concentration can be related to human organism dysfunctions, such as gout and renal disorders. An analytical procedure employing a flow system with solenoid micro-pumps was developed, aiming the determination of uric acid in urine samples. Cu(II) ions are reduced by uric acid to Cu(I) ions that can be quantified by spectrophotometry in the presence of 2,2´-biquinoline 4,4´-dicarboxylic acid (BCA). Linear analytical response was observed between 10 and 100 &#181;mol L-1 uric acid and the analytical curve corresponds to the equation A=(0.0063±0.0002) CUA + (0.0285±0.0040), r = 0.999, in which CUA is the uric acid concentration in &#181;mol L-1. The detection limit was estimated as 3.0 &#181;mol L-1 (99.7% confidence level; n = 20). The coefficient of variation was estimated in 1.2% with 20 replicates of a 75 &#181;mol L-1 uric acid solution and sampling rate of 150 h-1 was achieved. The main concomitant species does not interfere in uric acid determination in concentrations up to 5-fold higher than that usually found in urine samples. Recoveries from 91 to 112% were estimated and the results for 4 urine samples agreed with those obtained by the commercially available enzymatic kit for determination of uric acid (95% confidence level). The 100-fold sample dilution minimizes sample consumption and matrix effects. A simple system reconfiguration and a re-optimization of volumetric fractions attained on-line sample dilution by zone sampling. Linear response was observed up to 5.0 mmol L-1 uric acid and the analytical curve corresponds to the equation A=(0.105±0.001) CUA\' + (0.023±0.003), r = 0.999, in which CUA\' is the uric acid concentration in mmol L-1. The coefficient of variation, detection limit and sampling frequency were estimated as 1.0%, 0.2 mmol L-1 and 95 h-1, respectively. The results of the analysis of 3 urine samples also agreed with those obtained with the enzymatic procedure at the 95% confidence level

O trabalho apresentado nesta Dissertação de Mestrado descreve o desenvolvimento e aplicação de eletrodos de pasta de carbono modificados eletroquimicamente em soluções de guanina e de eletrodos de grafite pirolítico modificados em soluções de dopamina. Estes eletrodos foram empregados na detecção e, a quantificação, por voltametria de pulso diferencial (VPD), de alguns compostos de importância biológicas tais como NADH, NADPH, 8-oxo-guanina, ácido úrico (AU), ácido ascórbico (AA), dopamina (DA) e xantina (XA). No primeiro caso, os eletrodos de pasta de carbono foram modificados em solução de guanina por aplicação de um potencial de 1,1 V (vs Ag/AgCl, KClsat) ao eletrodo de trabalho por 12 minutos sob sat agitação constante. Com estes eletrodos detectaram-se NADH, NADPH, 8-oxo-guanina e AU, com limites de detecção de 3,3, 3,7, 2,0 e 6,6 x 10-6 mol L-1 respectivamente, na faixa de concentração de 7,5 x 10-6 a 8,1 x 10-4 mol L-1 . No segundo caso, eletrodos de grafite pirolítico, previamente tratados em solução de NaOH, foram modificados eletroquimicamente em solução de DA por aplicação de um potencial 1,5 V (vs Ag/AgCl, KClsat ) ao eletrodo de trabalho durante 2 minutos. Com estes eletrodos foi possível a determinação simultânea de AA, AU e DA. Para obtenção das curvas analíticas variou- se a concentração do analito de interesse, mantendo-se constante a concentração dos possíveis interferentes nos valores de 1,0 x 10-4 mol L-1 (DA), 5,0 x 10-5 mol L-1 (AU) e 1,0 x 10-3 mol L-1 (AA). Os limites de detecção calculados para AU, AA e DA foram respectivamente de 1,4 x 10-6 mol l-1 , 2,5 x 10-5 mol l-1 e 1,1 x 10-7 mol l-1 . Ácido úrico foi determinado em amostras de urina, sangue e soro humano com 92 a 103 % de recuperação, sem a necessidade de tratamento prévio das amostras. / Chemically Modified Carbon Paste and Pyrolitic Graphite Electrodes were prepared via electrochemical deposition from guanine and dopamine solutions. Carbon paste electrodes were modified in guanine solutions under an applied potential of 1.1 V (vs Ag/AgCl, KClsat ) during 12 minutes under constant stirring. They were used for sat electrochemical detection of NADH, NADPH, uric acid and 8-oxoguanine. Detection limits were 3.3, 3.7, 6.6 and 2.0 10-6 mol L-1 respectively, with sensitivity of 0.13, 0.10, 0.26 and 0.40 A mol-1 L cm-2 , respectively. The electrodes showed high reproducibility and absence of surface poisoning effects. Good analytical performance was attributed to the formation of superficial dimer or trimers species of guanine during the modification process. Pyrolitic graphite electrodes, previously submitted an electrochemical treatment in NaOH solution, were modified in dopamine solution (phosphate buffer, pH 10) under an applied potential of 1.5 V (vs Ag/AgCl, KClsat ) during 2 minutes under constant sat stirring and, further used for the simultaneous determination of ascorbic acid (AA), uric acid (AU) and dopamine (DA). The analytical curves were obtained changing the concentration of the wished analyte, at constant concentration levels of the interferences: 1.0 x 10-4 mol L-1 (DA), 5.0 x 10-5 mol L-1 (UA) and 1.0 x 10-3 mol L-1 (AA). Detection limits were 1.4 x 10-6 mol L-1 , 2.5 x 10-5 mol L-1 and 1.1 x 10-7 mol L-1 for UA, AA and DA, respectively. Uric acid was determined in human urine, blood and serum samples without any previous treatment. Recovering percentages of 92 to 103 % were obtained.

Introduction: Gout is a painful form of acute inflammatory arthritis associated with elevated uric acid crystal deposition especially in the joints, but also in tendons and the kidney. Between 1 and 2% of Western populations are affected and in severe cases, gout sufferers can be completely incapacitated. Despite the number of gout sufferers, the high number of risk factors and high incidence of adverse drug reactions using the standard treatment regimens, little research involving gout has been done within the highly diverse multiracial and multicultural population of South Africa. Hypothesis: This study was a hypothesis generating observational study to assess whether serum levels of pro-inflammatory cytokines and acute phase protein levels could be used as markers of the gout status of a patient. Method: Thirty gout patients were enrolled onto the study and attended two visits. At the screening visit; medical history, vital signs and demographic details were collected from intercritical gout patients. At both visits, patients completed visual analogue scales; namely: subject’s assessment of pain and subject’s assessment of disease activity. A doctor completed the physician’s assessment of disease activity at both of the visits. At the end visit, patients experiencing an acute gout attack were asked to list various foods and beverages that triggered said attacks. Patients were requested to return for their second visit as soon as they experienced a gout attack, however, those patients that did not experience a gout attack were asked to return to the clinic to complete the follow up visit four months after their baseline visit. Uric acid, IL-1β, TNF-α and CRP were measured for each patient at both visits. Results: Many of the patients displayed risk factors for metabolic syndrome. The mean subject’s assessment of pain score increased from 31mm at the screening visit to 40mm at the end visit (p=0.1947; n=26), while the mean subject’s assessment of disease activity score and the mean physician’s assessment of disease activity increased from 30mm to 37mm (p=0.3196; n=26) and 23mm to 35 mm (p=0.0937; n=26) respectively. Uric acid levels decreased from 1.053mmol/L to 0.871mmol/L between visits (p=0.0926; n=25) while CRP concentrations increased significantly from 10.2mg/L to 26.6mg/L (p=0.0278, n=24). IL-1β concentrations remained similar (12.17pg/ml to 12.54pg/ml) while TNF-α concentrations decreased from 12.63pg/ml to 3.54pg/ml, however neither of these were statistically significant differences. Upon stratifying results into active and non-active patients, both IL-1β and TNF-α concentrations decreased between non-active and active patients, while CRP and urate concentrations increased. However, none of these differences were statistically significant. Conclusion: The visual analogue scales all showed an increase between the screening and final visits, although this was not statistically significant. Uric acid concentrations decreased between visits, however this increase was once again not statistically significant. There appears to be no association between inflammatory markers and the level of gout activity, although this needs to be tested in a larger sample population. Results in South African patients have confirmed results from previous studies where gout patients are at a higher risk of metabolic syndrome than the normal population. Copyright / Dissertation (MSc)--University of Pretoria, 2011. / Pharmacology / unrestricted

Hyperlipidemia caused by a diet high in saturated fat can lead to visceral fat weight gain, obesity, and metabolic syndrome. Being over-weight from visceral fat has been linked to increased risk of developing most age-related diseases and disability, along with a lower income potential and quality of life. However, researchers are just beginning to understand the biological mechanisms that regulate the conversion of excess calories into visceral fat storage rather than glycogen or muscle. Epidemiological studies have repeatedly shown a comorbid association between age-related diseases involving hyperlipemia and circulating levels of uric acid, but not a direct association. This study utilized archival data from 31 healthy, middle-aged adults, who participated in a randomized, double-blind, crossover clinical trial on blood markers of lipidemia and inflammation following a high saturated fat (HSF) verses a "healthy" polyunsaturated fat (PUFA) meal. This primary study was conducted and funded by the National Institute on Aging. A secondary analysis of this data using Pearson's correlation with least squares (2-tailed) regression modeling found that when stratified by gender, baseline uric acid level was an independent and significant predictor of the lipemic response from the HSF, but not the PUFA meal. The linear regression plots indicated that males with uric acid levels above 4.5, and females above 3.0 mg/dL, had a progressively increased lipemic response to the HSF meal. The public health utility of this finding may include the clinical use of the gender-specific linear regression plots of uric acid values to identify and advise individuals at risk for hyperlipidemia from a diet high in saturated fats.

There are localised proteins (so-called urate transporters) in the renal proximal tubules and in the intestine, which excrete and reabsorb uric acid. Polymorphisms in the genes coding these proteins can result in the disruption of the transport function and development of hyperuricemia and gout. However the serum level of uric acid is also determined by other factors which include the intake of exogenous purines in food, synthesis of endogenous purines and degradation of nucleic acids, but also certain conditions. In 250 patients with primary hyperuricemia and gout we used Sanger sequencing to analyse the exons and adjacent intron regions in ten genes coding urate transporters: ABCG2, ABCC4, SLC2A9, SLC22A12, SLC22A11, SLC22A13, SLC17A1, SLC17A3, SLC22A6 and SLC22A8. We examined a possible connection between the identified genetic variants and primary hyperuricemia and gout based on a comparison of allele frequencies with the European population, according to topological models, according to programs predicting the functional impacts of variants and searches in specialised literature. We also took into account the conclusions of functional studies analysing the impact of nonsynonymous variants in the ABCG2 and SLC2A9 genes. We also focused on the effect of the concomitant occurrence of several...

<p>BACKGROUND: The ontogeny of peanut allergy (PA) is poorly understood, and the treatment of its most severe manifestation, peanut-induced anaphylaxis (PIA), remains limited to rescue epinephrine. We argued that an untargeted metabolomic analysis would be a useful hypothesis-generating tool to identify novel biomarkers, mediators and possibly therapeutic targets in PA and PIA.</p> <p>METHODS: Models of PA and PIA used in this thesis involved either the oral administration of peanut along with cholera toxin or the topical application of peanut on tape-stripped skin. Liquid-chromatography mass-spectrometry (LC-MS) was performed to identify chemical changes in the serum of mice undergoing sensitization and anaphylaxis. Flow cytometry as well as <em>in vivo</em> gain-of-function and loss-of-function immunological studies were used to determine the biological significance of particular molecules in sensitization.</p> <p>RESULTS: LC-MS followed by multivariant analysis showed that the purine metabolism pathway was altered with elevated levels of uric acid (UA) in sensitized mice. UA depletion using allopurinol and uricase fully prevented the development of the allergic and anaphylactic phenotype. Conversely, administration of UA crystals, instead of cholera toxin or tape stripping along with peanut induced a typical allergic and anaphylactic phenotype. The effects of UA and UA crystals are likely a consequence of effects on the activation of resident dendritic cells. Post-challenge metabolic analysis also revealed a distinct metabolic signature in sensitized mice, highlighted by an increase in several metabolites such as histamine. Likewise, peanut allergic patients display a distinct metabolic profile after oral peanut challenge.</p> <p>CONCLUSION: We identified UA, released after damage to the mucosa and/or skin, as a critical alarmin that facilitates the development of Th2 immunity, specifically PA and PIA. Metabolomics analyses of either mice undergoing anaphylaxis or peanut allergic children subjected to a peanut oral challenge provided an extensive overview of metabolomic changes underlying these conditions. Further studies may lead to the identification of novel biomarkers and mediators.</p> / Master of Science in Medical Sciences (MSMS)