Background-Nitric oxide (NO) and prostanoids are mediators of vascular and bronchial tone that are postulated to be involved in asthma. Increased levels of both are found in asthmatic subjects and are synthesised by enzymes that have cytokine inducible forms: inducible NO synthase (iNOS) and cyclo-oxygenase-2 (COX-2), respectively. We hypothesised that the in vivo expression of iNOS and COX-2 in the airways would be increased in asthma, and that these cytokine inducible enzymes may represent targets for regulation by corticosteroid treatment. Methods-Bronchial biopsy specimens were obtained from three groups of subjects: atopic asthmatics treated with 2 agonists alone (n=7), atopic asthmatics additionally receiving regular treatment with corticosteroids (n=8), and nonasthmatic control subjects (n=10). Expression of iNOS and COX-2 mRNA and immunoreactive protein was studied using in situ hybridisation and quantitative immunohistochemistry. Results-Immunoreactivity and the hybridisation signal for iNOS and COX-2 were mainly localised in the airway epithelium. The proportion of epithelium immunostained was significantly greater in the non-steroid treated asthmatic subjects (iNOS 8.6 (1.8)%; COX-2 26.3 (4.6)%) than either the steroid treated asthmatics (iNOS 3.4 (1.0)%, p=0.009; COX-2 13.0 (0.6)%, p=0.0015) or the non-asthmatic controls (iNOS 4.2 (0.9)%, p=0.018; COX-2 11.6 (0.6)%, p=0.0003). Similarly, the hybridisation signal was stronger in the non-steroid treated group of asthmatic subjects than in the other two groups. Conclusions-These findings highlight the potential role of the airway epithelium both as a contributor to the inflammatory process in asthma and as a target for inhaled corticosteroid treatment in this disease.

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Background-Two clinical formulae (CF conference formula and estimation based on 120% of average requirement for energy) have been recommended for the estimation of energy requirements in cystic fibrosis but their accuracy is unknown. Aim-To compare the accuracy of estimates of energy requirement derived from the two formulae. Methods-Energy requirement, defined as total daily energy expenditure, was measured using the doubly labelled water method in 15 patients (six girls, nine boys; mean (SD) age, 10.0 (2.4) years) who were well and clinically stable. The accuracy of the formulae was assessed using calculation of biases and limits of agreement relative to measured energy requirement. Results-Estimates from the CF conference formula were lower than measured values (mean paired diVerence, 0.52 MJ/ day; 95% confidence interval (CI), −1.10 to 0.10), but this bias was not significant, and was smaller than that from the alternative formula (mean paired diVerence, 0.77 MJ/day; 95% CI, −0.20 to 1.74). Limits of agreement relative to measured total daily energy expenditure were narrower for the CF conference formula (−2.72 to 1.68 MJ/ day) than for that based on 120% of estimated average requirement (−2.75 to 4.29 MJ/day), but with both formulae errors in estimation at the individual level were large. Conclusions-The CF conference formula oVers improved prediction of energy requirements, but the accuracy of both formulae at the individual level is not sufficiently good for clinical purposes. (Arch Dis Child 1999;81:120-124)

Starch digestion and oxidation are diminished in children with cystic fibrosis, but pancreatic enzymes restored them to near normal levels. A second peak in 13CO2 enrichment, suggestive of colonic starch fermentation was absent in healthy children, but present in some children with cystic fibrosis and abolished by pancreatic enzymes.