ABSTRACr A rapid, simple method for measuring bronchial responsiveness to inhaled histamine is described. The method was used to obtain dose response curves in 50 atopic subjects with varying respiratory and nasal symptoms. The cumulative dose of histamine which caused a 20% fall in the one second forced expiratory volume (PD2>FEV.) varied between 0*046 and greater than 39 ,umol and correlated with the severity of symptoms. The reproducibility of the PD2,FEv,, determined from duplicate measurements in 15 subjects with varying degrees of bronchial responsiveness was found to be satisfactory. When the PD2OFEV, from this rapid method was compared with that obtained from the dosimeter method no significant difference was found. The dose delivered by this method was shown to be cumulative. May 1983 drive the nebuliser, so the equipment is cumbersome.

A study was done to compare the efficacy and safety of the coprescription of salmeterol 50 microgram twice daily or 100 microgram twice daily with beclomethasone dipropionate (BDP) 500 micrograms twice daily (SALM 50 and SALM 100) with BDP 1,000 microgram twice daily (BDP 1,000) in patients with asthma not controlled by BDP 500 microgram twice daily (or the equivalent). Following a run-in period, 738 patients at 72 centers were randomized to treatment for 24 wk in a double-blind, parallel-group study during which they maintained a daily record of peak expiratory flow rates (PEFRs) and symptom scores. At about 40 of the centers, bronchial hyperresponsiveness (BHR) to histamine was measured during and at 3 and 14 d after stopping treatment. Both groups taking salmeterol showed an improvement of more than 45 L/min in their morning PEFR and 30 L/min in their evening PEFR, compared with respective improvements of 16 L/min and 6 L/min in the group taking BDP 1,000. Both the SALM 50 and SALM 100 groups had a significantly increased percentage of symptom-free and rescue-free days and nights compared with the BDP 1,000 group, and there was no difference between the two salmeterol groups. None of the treatments altered BHR. Exacerbation rates did not differ among the three groups. We conclude that in this selected group of symptomatic patients taking BDP 500 micrograms twice daily, the addition of salmeterol provides better improvement in lung function and symptom control, without altering BHR or increasing exacerbation rates, than does doubling the dose of BDP.

Objective-To investigate whether prevalence of asthma in children increased in 10 years.

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To determine predictors for failed reduction of inhaled corticosteroids (ICS), in 50 subjects with well-controlled asthma (age 43.7 [18-69]; 22 males) taking a median dose of 1,000 microg ICS/d (100-3,600 microg/d), ICS were halved every 8 wk. Airway hyperresponsiveness (AHR) to a bronchial provocation test (BPT) with histamine was measured at baseline. AHR to BPT with mannitol, spirometry, exhaled nitric oxide (eNO), and, in 31 subjects, sputum inflammatory cells were measured at baseline and at monthly intervals. Thirty-nine subjects suffered an asthma exacerbation. Seven subjects were successfully weaned off ICS. Using a Kaplan- Meier survival analysis, the significant predictors of a failure of ICS reduction were being hyperresponsive to both histamine and mannitol at baseline (p = 0.039), and being hyperresponsive to mannitol during the dose-reduction phase of the study (p = 0.02). Subjects older than 40 yr of age tended to be at greater risk of ICS reduction failure (p = 0.059). Response to mannitol and percentage sputum eosinophils were significantly greater before a failed ICS reduction than before the last successful ICS reduction, whereas there were no significant differences in symptoms, spirometry, or eNO. These findings suggest that documentation of patient's AHR or sputum eosinophils may be useful in guiding the reduction of ICS doses.

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Objective: To investigate the association between diet and airway disease in children in the light of epidemiological studies suggesting that consumption of fish more than once a week reduces the risk of developing airway hyperresponsiveness (AHR).Design: Diet was assessed by a detailed food frequency questionnaire and airway disease by respiratory symptoms or airway responsiveness to exercise.Methods: A questionnaire, containing questions about the frequency of eating more than 200 foods, was sent to the parents of 574 children in whom we had measured recent wheeze (by questionnaire), AHR (by exercise) and atopy (by skin prick tests) six months before this study. We defined current asthma as the presence of both recent wheeze and AHA.Results: Response rate to the questionnaire was 81.5% (n=468). After adjusting for confounders such as sex, ethnicity, country of birth, atopy, respiratory infection in the first two years of life and a parental history of asthma or smoking, children who ate fresh, oily fish (>2% fat) had a significantly reduced risk of current asthma (odds ratio, 0.26; 95% confidence interval, 0.09-0.72; P<0.01). No other food groups or nutrients were significantly associated with either an increased or reduced risk of current asthma.Conclusion: These data suggest that consumption of oily fish may protect against asthma in childhood.