Clinical science
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1. Patency of the upper airway is critical to respiration. Although about half of patients with the sleep apnoea/hypopnoea syndrome obstruct their upper airway at the retropalatal level, the respiratory actions of the palatal muscles have been little studied. ⋯ One hundred milliseconds after negative pressure application, activity increased in both genioglossus (7% +/- 2% and 13% +/- 3% respectively, P = 0.02) and palatoglossus (8% +/- 2% and 23% +/- 6% respectively, P < 0.001). After lignocaine surface anaesthesia to the nose and pharynx both genioglossus and palatoglossus still increased their activity in response to negative upper airway pressure, the extent of the increase being decreased for palatoglossus (P = 0.02) but not for genioglossus. 5. Thus, palatoglossus has respiratory activity and is activated by negative upper airway pressure.
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Randomized Controlled Trial Clinical Trial
Effect of oral digoxin, topical ouabain and salbutamol on transepithelial nasal potential difference in patients with cystic fibrosis.
1. Airway epithelium in cystic fibrosis is characterized by a defect in chloride secretion across the apical membrane and an increase in sodium absorption. The increased rate of sodium absorption can be inhibited in vitro by ouabain, a Na(+)-K(+)-ATPase inhibitor, and in cystic fibrosis patients the number and activity of nasal epithelial Na(+)-K(+)-ATPase pumps is increased. 2. ⋯ In study 1, nasal potential difference measurements were repeated on non-consecutive days in 20 patients with cystic fibrosis and 20 healthy individuals. Healthy subjects had a mean (SEM) potential difference value of -19.5 (0.9) mV with a 95% range for a single estimate of 75-133%. In patients with cystic fibrosis, the mean (SEM) potential difference was -40.4, (2.1) mV, with a 95% range for a single estimate of 74-136%.(ABSTRACT TRUNCATED AT 250 WORDS)