Background: Acoustic rhinometry is a noninvasive method that uses sound waves to measure dimensions of the nasal cavity. Methods: In this study, nasal patency was measured by acoustic rhinometry in allergic Beagle dog...
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Background: Acoustic rhinometry is a noninvasive method that uses sound waves to measure dimensions of the nasal cavity. Methods: In this study, nasal patency was measured by acoustic rhinometry in allergic Beagle dogs sensitized to ragweed allergen. Ragweed (0.03-0.3%) or vehicle were administered intranasally in isoflurane-anesthetized dogs. Results: The instillation of ragweed caused a dose-related decrease in nasal cavity volume and minimal cross-sectional area (A(min)) without adverse systemic effects. Nasal cavity volume and A(min) decreased within 30 minutes after instillation of the highest ragweed dose by 35.1 +/- 6.0% and 66.4 +/- 13.8%, respectively, and persisted for at least 90 minutes. Oral administration of alpha-adrenergic agonist, d-pseudoephedrine (3 mg/kg), or histamine H-1 antagonist chlorpheniramine (10 mg/kg) blocked the ragweed-induced nasal congestion. Conclusion: These results suggest that the canine model may be used to study upper-airway diseases such as allergic rhinitis and to evaluate the pharmacologic activity of nasal decongestants.
Acute effects of oral terbutaline (5 mg), ephedrine (25 mg) and placebo on bronchial dynamics, heart rate, systolic and diastolic pressure and arterial blood gases at rest were compared over a period of 7 hours in 20 ...
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Acute effects of oral terbutaline (5 mg), ephedrine (25 mg) and placebo on bronchial dynamics, heart rate, systolic and diastolic pressure and arterial blood gases at rest were compared over a period of 7 hours in 20 subjects with bronchial asthma using a double-blind crossover technique. Both terbutaline and ephedrine caused significant bronchodilation, but the effect of terbutaline on specific airway conductance (SGA) was significantly greater (peak mean increase in SGA 0.069 vs 0.027 L/sec/cm H2O/L), had an earlier onset (30 minutes vs 1 hour) and lasted longer (7 hours vs 4 hours) than that of ephedrine. Slight but significant increases in arterial P02 were noted following institution of both ephedrine and terbutaline, suggesting improvement in ventilation-perfusion relationships. Both drugs caused modest but statistically significant increases in heart rate of 8.4-10.9 beats/min and the mean peak increase following terbutaline (8.4 beats/min) was comparable to that following ephedrine. In contrast to ephedrine, terbutaline caused significant, although slight, increases in systolic pressure and decreases in diastolic pressure, indicating that this drug, in the dose recommended for clinical use, is not free of cardiovascular effects.
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