The disruption of proteostasis in neurodegenerative diseases

Cells count on surveillance systems to monitor and protect the cellular proteome which, besides being highly heterogeneous, is constantly being challenged by intrinsic and environmental factors. In this context, the proteostasis network (PN) is essential to achieve a stable and functional proteome. Disruption of the PN is associated with aging and can lead to and/or potentiate the occurrence of many neurodegenerative diseases (ND). This not only emphasizes the importance of the PN in health span and aging but also how its modulation can be a potential target for intervention and treatment of human diseases.info:eu-repo/semantics/publishedVersio

Effects of different self-assembled monolayers on enzyme immobilization procedures in peroxidase-based biosensor development

Different immobilization procedures for horseradish peroxidase (HRP) were investigated using, as support matrices, self-assembled monolayers (SAM) formed on gold electrodes. The influences of these immobilization processes in the biosensor performance were also evaluated. For this, monolayers were prepared from thiols with different structures, carbon chain sizes and terminal groups. It wits shown that the thiol carbon chain size influences especially in monolayer coverage and, consequently, in the biomolecule immobilization efficiency. From the studies carried out for SAM characterization on the electrode surface it was verified that thiols with shorter chains (n < 9) tend to form monolayers with a considerable amount of defects on the gold surface that lead to a lower coverage. However, thiols with a longer carbon chain present a higher coverage degree, which are not suited as substrate to the development of electrochemical biosensors, because they passivate the transduction interface, making difficult the electron transfer and, consequently, reducing electrode sensitivity. In relation to the enzyme immobilization on gold electrodes, it was verified, using different techniques, that monolayers that possess -NH2 terminal groups provided the best results, probably due to the use of glutaraldeyde as ligand during the immobilization process. Analyzing biosensor performances for hydrogen peroxide, it was verified that SAM formed by cysteamine is the most adequate for HRP immobilization, because it provides better efficiency for enzyme immobilization associated to high sensitivity for H2O2. (c) 2007 Elsevier B.V. All rights reserved.612216417

Electrochemical detection of cysteine in a flow system based on reductive desorption of thiols from gold

A simple strategy for cysteine determination using flow-injection analysis with electrochemical detection is described. The approach is based on the chemisorptions reactions of the sulfur moiety of cysteine upon polycrystalline gold electrodes and its subsequent reductive desorption. The electrochemical measurements were accomplished by the application of differential pulse voltammetry (DPV) for the operational optimization and pulsed electrochemical detection (PED) in combination with flow-injection analysis for the electrochemical detection as time function. The electroactive species could be adsorbed in a potential level (0.1 V versus SCE), at other (-0.6 V versus SCE) occurs their reductive desorption from the electrode, while the analytical current is recorded simultaneously, and a third potential step is applied to the complete regeneration of the gold electrode surface (-1.3 V versus SCE). The linear response range was observed between 1.0 x 10(-6) and 6.0 x 10(-6) mol L-1 with a good reproducibility (R.S.D. < 3.2%) and sensitivity (1.1 mu A/mu M). The repeatability (a series of 27 continuous FIA peaks of 5.0 mu mol L-1 of cysteine) was 3.8 % and the limit of detection was 5.0 x 10(-7) mol L-1. The sample throughput was 23 samples per hour with a very high stability in its voltammetric response. The developed methodology was successfully used for the determination of cysteine in commercial supplementary food sample. (c) 2006 Elsevier B.V. All rights reserved.575217217

Electrochemical Detection in a Paper-Based Separation Device

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Prototypes of microfluidic paper-based separation devices with amperometric detection were developed and evaluated. Photolithography was used to make a gold electrochemical microcell on polyester and that microcell was coupled to a strip of paper where a chromatographic separation occurs. The device performance was demonstrated with the separation and quantification of uric and ascorbic acid in mixtures. The method provides an analytical alternative for the determination of compounds where low cost and simplicity are essential.82311621165Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)INCTBIO (Instituto Nacional de Ciencia e Tecnologia de Bioanalitica)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Development of a disposable amperometric biosensor for salicylate based on a plastic electrochemical microcell

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The use of an amperometric biosensor for rapid salicylate determination in blood is described. Photolitography was used to make gold electrodes on a polyester film. The plastic microcell was characterized using cyclic voltammetry to demonstrate the electrochemical performance of the system. The biosensor was constructed by immobilizing salicylate hydroxylase onto the working electrode of the plastic electrochemical microcell. The optimized working conditions were 0.1 mol L(-1) phosphate buffer at pH 7.6 with 0.5 mmol L(-1) of NADH and 300 mV vs. Au as the applied potential. The resulting biosensor exhibited a high sensitivity (97.4 nA/mmol L(-1) salicylate) and an adequate linear response range (1.2 x 10(-4) to 1.0 x 10(-3) mol(-1)). The biosensor performance was verified by determining salicylate in spiked blood samples and the results were statistically equivalent to the values obtained from the standard Trinder spectrophotometric method, with a 95% confidence level. This study shows the potential development of a portable, inexpensive and disposable device for point-of-care monitoring. (C) 2010 Elsevier B.V. All rights reserved.251022002204Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Probing the surface oxidation of chemically synthesised gold nanospheres and nanorods

In this study, the electrochemical behaviour of commercially available gold spheres and rods stabilised by carboxylic acid and cetyl trimethyl ammonium bromide (CTAB) moieties, respectively, are investigated. The cyclic voltammetric behaviour in acidic electrolyte is distinctly different with the nanorods exhibiting unusual oxidative behaviour due to an electrodissolution process. The nanospheres exhibited responses typical of a highly defective surface which significantly impacted on electrocatalytic activity. A repetitive potential cycling cleaning procedure was also investigated which did not improve the activity of the nanorods and resulted in deactivating the gold spheres due to decreasing the level of surface defects

Produção científica sobre eliminações urinárias em periódicos de enfermagem brasileiros Producción científica sobre eliminaciones urinarias en periódicos de enfermería brasileños Scientific literature on urinary elimination in Brazilian nursing journals

OBJETIVO: Verificar a produção científica sobre eliminações urinárias divulgada em periódicos de enfermagem brasileiros. MÉTODOS: Estudo realizado por meio de revisão integrativa da literatura, contemplando as bases de dados MEDLINE, LILACS e Web of Science, utilizando 30 descritores para busca de artigos publicados entre 1999 a 2009; assim, foram selecionados 18 artigos, disponíveis na integra, produzidos por enfermeiros. Os manuscritos foram analisados tendo por base um instrumento de coleta de dados discriminando-se nome do periódico, ano de publicação, tipo do estudo, assunto abordado e nível de evidências. RESULTADOS: Os 18 estudos foram classificados com nível de evidência IV e a incontinência urinária foi o tema mais freqüente nos artigos analisados. CONCLUSÃO: Embora as alterações nas eliminações urinárias integrem a prática clínica do enfermeiro, nos artigos selecionados, o tema foi limitado a um âmbito restrito de assuntos, com baixo nível de delineamento, oriundos da produção de reduzido número de autores, indicando a importância de maior investimento em pesquisas nessa área<br>OBJETIVO: Verificar la producción científica sobre eliminaciones urinarias difundidas en periódicos de enfermería brasileños. MÉTODOS: Estudio realizado por medio de revisión integrativa de la literatura, contemplando las bases de datos MEDLINE, LILACS y Web of Science, utilizando 30 descriptores para búsqueda de artículos publicados entre 1999 al 2009; así, fueron seleccionados 18 artículos, disponibles íntegramente, producidos por enfermeros. Los manuscritos fueron analizados teniendo como base un instrumento de recolección de datos discriminándose el nombre del periódico, año de publicación, tipo del estudio, asunto abordado y nivel de evidencias. RESULTADOS: Los 18 estudios fueron clasificados con nivel de evidencia IV y la incontinencia urinaria fue el tema más frecuente en los artículos analizados. CONCLUSIÓN: A pesar que las alteraciones en las eliminaciones urinarias integren la práctica clínica del enfermero, en los artículos seleccionados, el tema fue limitado a un ámbito restringido de asuntos, con bajo nivel de delineamiento, procedentes de la producción de un reducido número de autores, indicando la importancia de una mayor inversión en investigaciones en esa área<br>OBJECTIVE: To assess the scientific literature on urinary elimination in nursing journals published in Brazil. METHODS: An integrative literature review was used to review the databases MEDLINE, LILACS and Web of Science. The authors used 30 descriptors to search for articles published between the years 1999 to 2009, resulting in a total of 18 articles that met criteria and which were published by nurses. The papers were analyzed using a data collection instrument to identify journal name, year of publication, type of study, subject matter, and level of evidence. RESULTS: Eighteen studies were classified as Level of Evidence IV; urinary incontinence was the most frequent theme in the articles analyzed. CONCLUSION: While the clinical practice of nurses was integrated into articles addressing changes in urinary elimination, we found that this topic was narrowly defined, studies used lower level research designs, and it was noted that few authors published on the topic. All of these findings indicate the importance of greater investment in nursing research in this area of nursing knowledge and practic