Laryngeal and voice disorders in patients with gastroesophageal symptoms. Correlation with pH-monitoring

OBJETIVO: Investigar as alterações laríngeas e vocais em pacientes com sintomas de refluxo gastroesofágico e correlacioná-las com o exame de phmetria. MÉTODOS: Estudo prospectivo que incluiu os pacientes atendidos nos ambulatórios de Distúrbios da Voz da Faculdade de Medicina de Botucatu no período de cinco anos com sintomas vocais e gastroesofágicos. Os pacientes foram submetidos à videolaringoscopia, às análises vocais perceptivo-auditivas, a analise vocal acústica computadorizada e ao exame de pHmetria de dois canais com monitorização durante 24 horas. RESULTADOS: Foram incluídos 57 pacientes (entre 21 a 65 anos; 45 mulheres e 12 homens). Desses, 18 apresentavam pHmetria normal (31,6%) e 39 alterada (68,4%). As videolaringoscopias registraram diversas lesões laríngeas tanto nos pacientes com pHmetria normal como alterada, sendo mais relevantes neste último grupo, destacando-se a paquidermia posterior. As avaliações vocais perceptivo-auditivas identificaram alterações vocais de diversas intensidades em ambos os grupos, mais importantes nos pacientes com pHmetria alterada. Todos os parâmetros acústicos, exceto Fo, mostraram-se alterados em ambos os grupos, quando comparados aos controles. CONCLUSÕES: Alterações vocais perceptivas e acústicas, e lesões laríngeas foram registradas tanto nos pacientes com phmetria normal como alterada, sinalizando para a importância da historia clínica e dos achados videolaringoscópicos no diagnóstico das laringites ácidas.

The Use of Response Surface Methodology in Optimization of Lactic Acid Production: Focus on Medium Supplementation, Temperature and pH Control

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Rhamnolipid emulsifying activity and emulsion stability: pH rules

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A stability transition at mildly acidic pH in the alpha-hemolysin (alpha-toxin) from Staphylococcus aureus

The effects of mildly acidic conditions on the free energy of unfolding (Delta G(u)(buff)) of the pore-forming alpha-hemolysin (alpha HL) from Staphylococcus aureus were assessed between pH 5.0 and 7.5 by measuring intrinsic tryptophan fluorescence, circular dichroism and elution time in size exclusion chromatography during urea denaturation, Decreasing the pH from 7.0 to 5.0 reduced the calculated Delta G(u)(buff) from 8.9 to 4.2 kcal moI(-1), which correlates with an increased rate of pore formation previously observed over the same pH range, It is proposed that the lowered surface pH of biological membranes reduces the stability of alpha HL thereby modulating the rate of pore formation. (C) 1999 Federation of European Biochemical Societies.

Interfacial surface charge and free accessibility to the PLA(2)-active site-like region are essential requirements for the activity of Lys49 PLA(2) homologues

Lys49 phospholipase A(2) homologues are highly myotoxic and cause extensive tissue damage but do not display hydrolytic activity towards natural phospholipids. The binding of heparin, heparin derivatives and polyanionic compounds such as suramin result in partial inhibition (up to 60%) of the myotoxic effects due to a change in the overall charge of the interfacial surface. In vivo experiments demonstrate that polyethylene glycol inhibits more than 90% of the myotoxic effects without exhibiting secondary toxic effects. The crystal structure of bothropstoxin-I complexed with polyethylene glycol reveals that this inhibition is due to steric hindrance of the access to the PLA(2)-active site-like region. These two inhibitory pathways indicate the roles of the overall surface charge and free accessibility to the PLA2-active site-like region in the functioning of Lys49 phospholipases A(2) homologues. Molecular dynamics simulations, small angle X-ray scattering and structural analysis indicate that the oligomeric states both in solution and in the crystalline states of Lys49 phospholipases A2 are principally mediated by hydrophobic contacts formed between the interfacial surfaces. These results provide the framework for the potential application of both clinically approved drugs for the treatment of Viperidae snakebites. (c) 2006 Elsevier Ltd. All rights reserved.