The clinical efficacy and safety of Netilmicin (NTL) and Sisomicin (SISO) were compared in this randamized, double-blind study of 226 patients with respiratory tract infections .
We have investigated the effect of nifedipine on acetylcholine-induced bronchoconstriction in 8 asthmatics and on histamine-induced bronchoconstriction in another 8 asthmatics on a single-blind basis. Expiratory spirograms were done at the beginning of the examination in all subjects, and repeated after 10 mg of oral nifedipine or a placebo. The change of respiratory resistance during the inhalation of acetylcholine or histamine was recorded continuously by an Astograph庐. Using this device, we were able to obtain the direct-writing dose-response curve of respiratory resistance measured during quiet breathing. Resting airway tone appeared to be generally unaffected by nifedipine, as there was no significant change in baseline spirograms. Nifedipine increased significantly the threshold of bronchial responsiveness, i.e., the cumulative dose of acetylcholine (Dmin) at which the respiratory resistance started to increase, compared with placebo (p < 0.02). However, Sd, the slope of the increasing rate of respiratory resistance in the dose-response curve, was not attenuated by nifedipine. In histamine inhalation tests, neither Dmin nor Sd were modified by nifedipine. The discrepancy observed between the effects of nifedipine on acetylcholine- and histamine-induced bronchoconstriction may imply that, in asthmatics, nifedipine exerts its effect mainly by stabilizing mast cells rather than by directly inhibiting bronchial smooth muscle contractility. This hypothesis is based on the fact that mast cells have acetylcholine receptors on their surfaces but no histamine H1-receptors
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations鈥揷itations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.