Archives of disease in childhood
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There is much interest in the use of holding chambers with an attached facemask to deliver aerosols from metered dose inhalers to infants. In order to study the influence of various design factors on the dose inhaled at different tidal volumes, a model was constructed in which a Starling ventilator was used to generate an inspiratory/expiratory cycle across a filter. Sodium cromoglycate was administered via a Nebuhaler and mask, Aerochamber and mask, and a coffee cup using tidal volumes of 25, 50, and 150 ml and the dose deposited upon the filter after six breaths was assayed using an ultraviolet spectrophotometric method. ⋯ Multiple breaths ensured that the dose inhaled per kilogram from each chamber was relatively large and also permitted significant drug delivery despite the introduction of a relatively large dead space between valve and filter. The dose delivered was increased by increasing the dose introduced into the chamber though not proportionately. These devices appear likely to deliver significant quantities of aerosol to infants, though drug delivery may be enhanced by the use of an appropriate valve.
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Soluble interleukin-2 receptor (sIL-2R-CD25) concentrations were measured in the sera of 115 children with cystic fibrosis and 45 aged matched controls. Above the age of 4 years children with cystic fibrosis had significantly raised concentrations irrespective of disease status as judged by Shwachman score, lung function, or evidence of pseudomonas colonisation. It is believed that these data indicate that T lymphocyte activation can be detected before there is clinical evidence of lung inflammation due to infection in cystic fibrosis. They support the notion that early use of anti-inflammatory (immunosuppressive) drugs may have a role in delaying the progress of lung damage in cystic fibrosis.