Activity of nitric oxide (NO) synthases is increased in the bronchial epithelium of allergic asthmatics following allergen provocation.

<p>Bronchial biopsies were collected during fiberoptic bronchoscopy of allergic asthmatics (n = 9), before (light grey) and 24 hours after allergen provocation (dark grey). Representative image of the epithelial (Ep) activity of NO synthases was assessed by nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) staining (purple) in bronchial biopsies from allergic asthmatics A) before and B) after allergen provocation. C) Morphometric analysis was performed. Samples where intact bronchial epithelium could not be identified were omitted from the analysis. Epithelial cells detached from the basal membrane were excluded. Percentage of bronchial epithelium stained positive for NAPDH-d. Significant differences were assessed using paired t-test. Scale bars indicate 200 µm. * indicates p<0.05.