S Sa al lm me et te er ro ol l i in n e ex xe er rc ci is se e--i in nd du uc ce ed d b br ro on nc ch ho oc co on ns st tr ri ic ct ti io on n i in n a as st th hm ma at ti ic c c ch hi il ld dr re en n: : c co om mp pa ar ri is so on n o of f t tw wo o d do os se es s Twelve children (aged 7-14 yrs) with asthma were studied in a double-blind, cross-over, placebo-controlled design. On three separate days, exercise tests were performed 1 h and 12 h after administration of the drug. Pulmonary function measurements were performed before drug inhalation, before every exercise test and 1, 5, 10, 15 and 30 min after the end of exercise. The response was expressed as maximal decrease in forced expiratory volume in one second (FEV1).Both doses of salmeterol provided significant bronchodilation for up to 12 h, with no difference between them. Maximal exercise-induced decrease in FEV1 (% fall) 1 h after pretreatment was (mean±SD) 35±16, 10±10 and 4±3% for placebo, 25 and 50 µg salmeterol, respectively. At 12 h after pretreatment these values were 31±14, 19±12 and 15±13%, respectively. Individual protection against exercise-induced bronchoconstriction at 1 and 12 h did not vary between the dosages (p<0.05), even though the protection obtained by 25 µg at 12 h was no longer significant versus placebo.We conclude that 25 µg of inhaled salmeterol provides equally effective long-lasting bronchodilation and acute protection against exercise-induced bronchoconstriction as 50 µg, and may be a suitable dose for most asthmatic children.
A study was designed to determine the sensitivity and specificity of a cold air bronchial provocation test. A total of 18 children with asthma (mean age 12 years) and 18 normal children (mean age 14 years) were studied. The cold air challenge consisted of a 4 min period of isocapnic hyperventilation of subfreezing air (mean temperature -15 degrees C). In-Induced response in forced expiratory volume in 1 sec (FEV1) expressed as a percentage of predicted normal values was obtained at 4, 6, and 8 min post-challenge. The average response to the cold air was a 27% decrease of FEV1 in asthmatics, which was significantly different from that of the normal children, who showed no statistically significant drop. In both the asthmatic and normal groups, the maximal drop in FEV1 had occurred by the time measurements 4 min post-challenge had been made. At that time, the smallest overlap was observed between normal and asthmatic children. This suggests that the fourth minute post-challenge can be chosen as a cut-off time to distinguish normal from asthmatic children. Considering a decrease of FEV1 greater than 10% as a positive test, the sensitivity of the cold air challenge was 95% and the specificity was 89%.
The biological role of T cell receptor (TCR) gamma delta bearing cells is not yet fully understood. We studied 12 children with Bordetella pertussis infection and 12 age- and sex-matched healthy controls. Patients with whooping-cough yielded significantly lower relative and absolute numbers of blood TCR-gamma delta + cells than normal controls (both p < 0.001). It is suggested that the depletion of circulating gamma delta T cells in patients with Bordetella pertussis infection might be the result of the dispatch of these cells to the site of inflammation, i.e. the bronchial mucosa. Interestingly, other human lung diseases, such as allergic bronchial asthma and sarcoidosis display similar pulmonary phenotypical features.
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