Allergen-Induced Bronchoconstriction in Asthmatic Children (7)
BN52021 at the concentration of 50 ng/ml had only a little effect on PAF-induced bronchospasm; at a concentration of 150 ng/ml, BN52021 could inhibit PAF-induced bronchospasm in four of the six responders and at a concentration of450 ng/ml, BN52021 was capable of preventing PAF-induced bronchospasm in all six responders. However, as the dose-response study of BN52021 was done successively, a cumulative effect of BN52021 should be considered. After the dose-dependent nature of inhibitory effect of BN52021 on PAF-induced bronchospasm was established, BN52021 at a concentration of450 ng/ml was used in the methacholine and allergen challenge studies.
The specificity of the inhibitory effect of BN52021 on PAF-induced bronchospasm was studied by using methacholine challenge. Figure 2 shows that there was no difference in methacholine PD20 units between placebo and BN52021 pretreated groups (40.8 ±20.2 U vs 41.2 ±20.6 U).
To study the possible role of PAF in the pathogenesis of allergic bronchial asthma — Buy Advair Diskus Online, a double-blind, placebo-controlled, crossover allergen challenge study was conducted. Patients were instructed to inhale either BN52021 or placebo and then perform the allergen challenge. Two tests were done seven days apart.
Figure 2. Specificity of inhibitory effect of BN52021 on platelet-activating factor (PAF)-induced bronchoconstriction. Each subject inhaled either placebo (A) or BN52021 (B) in a double-blind, crossover fashion and then performed methacholine challenge. No difference in methacholine PD20 units was found between placebo group and BN52021 pretreated group. Thus, BN52021 had no protective effect on methacholine-induced bronchoconstriction.