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Thirteen allergic adolescent subjects without clinical asthma but with exercise-induced bronchoconstriction participated in this study. In a double-blind protocol, they were given placebo, 4 mg, or 12 mg chlorpheniramine at bedtime the evening before exposure to 1 ppm sulfur dioxide (S02) during moderate exercise. Pulmonary function (forced expiratory volume in 1 second and total respiratory resistance) and nasal work of breathing were measured before and after exposure. Chlorpheniramine did not alter the statistically significant changes in pulmonary function seen after SO, exposure. However, 12 mg chlorpheniramine did block the S02-induced increase in the nasal work of breathing. It is concluded that treatment with an H, blocking antihistamine does not affect the mecha¬ nisms underlying S02-induced bronchoconstriction, although it does inhibit S02-induced nasal function changes.

Human nasal turbinate tissue from surgical specimens was dissected free of connective tissue, and primary epithelial cultures were established by explant techniques. Transmission electron microscopy revealed that cultured cells retained homogeneous cytoplasmic granules, tonofilaments, and desmosomes and formed a homogeneous monolayer. The epithelial cells stained positively with cytokeratin antibodies AE1, AE3, and 35BH11 but failed to stain with two other cytokeratin antibodies, AE2 and 34BE12. Staining was also positive with anti-desmoplakin I and II but negative with antivimentin (43BE8), anti-desmin, and anti-human factor VIII antibodies. Cultured cells were exposed to filtered air or sulfur dioxide at 1-5 ppm for 30-60 min. Although there was no increase in cell lysis as measured by chromium-51 release, SO2 exposure significantly inhibited [3H]leucine incorporation compared to air exposure. This effect was dependent on both SO2 concentration and exposure duration. Control experiments revealed that these SO2 effects were not caused by the [H+] load produced by SO2 exposure. Electron microscopy of cells exposed to air or SO2 did not show any significant morphological differences.