Bronchoalveolar neutrophilia during late asthmatic reactions induced by toluene diisocyanate

Developments in anti-asthma glucocorticoids

Studies carried out by Swedish and English workers in the mid 1950s appear to be the first successful uses of topical glucocorticoids in asthma. As shown with beclomethasone dipropionate during the 1970s, and expanded with budesonide during the 1980s, inhaled glucocorticoids have a very broad clinical efficacy and are safe to use. With increasing lung selectivity glucocorticoid drugs may well become a primary treatment for asthma. Even prolonged treatment with large doses of budesonide may not affect the contractile and relaxant characteristics of airway smooth muscle suggesting that this tissue is not a direct target for glucocorticoid actions. In IgE-sensitized guinea-pigs, as in atopic asthmatics, inhalational budesonide and other glucocorticoids inhibit both immediate and late phase pulmonary reactions occurring after allergen provocation. The anti-anaphylactic lung effects of glucocorticoids are not necessarily associated with inhibition of histamine and leukotriene release and, although PAF release was reduced by budesonide, the importance of this effect is as yet unknown. Airway eosinophilia is seen at the late phase reaction but may not consistently be reduced by glucocorticoids. These drugs reduce plasma leakage that is associated with both atopic and non-atopic asthma. Hence, a stabilising effect on airway endothelial-epithelial barriers may be one of the significant actions of glucocorticoids in the inflamed airways of patients with asthma or chronic obstructive pulmonary disease.

Atropine does not inhibit late asthmatic responses induced by toluene-diisocyanate in sensitized subjects

To determine whether early and/or late asthmatic responses induced by toluene diisocyanate (TDI) are caused by a reflex mechanism involving stimulation of muscarinic receptors, we studied the effect of the muscarinic antagonist atropine on early and late airway response induced by TDI. A preliminary study was conducted in asthmatics to assess whether the selected dose of atropine provided adequate muscarinic blockade. On different days we measured the provocation dose (in milligrams) of carbachol causing a 15% decrease in FEV1 (PD15FEV1) without and with atropine premedication (0.008 or 0.012 mg/kg subcutaneous atropine 30 or 90 min before carbachol challenge test). We found that 0.008 to 0.012 mg/kg subcutaneous atropine increased the PD15FEV1 carbachol by 6- to 10-fold, inducing a consistent and prolonged decrease in nonspecific bronchial hyperresponsiveness to cholinergic agent. Then we examined 10 subjects with a history of sensitization to TDI in 2 sets of experiments. In the first set of experiments, we studied the subjects before and after exposure to TDI (0.04 ppm; 30 min) after no treatment. In the second set of experiments, carried out 1 to 2 wk later, we repeated the same procedure after treatment with atropine (0.008 to 0.012 mg/kg atropine sulfate administered subcutaneously 30 min before TDI challenge, and then at 90-min intervals after TDI exposure); all patients showed symptoms of atropine effect (dryness of mouth, cycloplegia, increased heart rate).(ABSTRACT TRUNCATED AT 250 WORDS)