Increased prandial air swallowing and postprandial gas-liquid reflux among patients refractory to proton pump inhibitor therapy.

BACKGROUND & AIMS: Many patients with gastroesophageal reflux disease (GERD) have persistent reflux despite treatment with proton pump inhibitors (PPIs). Mixed gas-liquid reflux events are more likely to be perceived as symptomatic. We used esophageal impedance monitoring to investigate whether esophageal gas is processed differently among patients with GERD who do and do not respond to PPI therapy. METHODS: We performed a prospective study of 44 patients with typical reflux symptoms with high levels of esophageal acid exposure during a 24-hour period; 18 patients were fully responsive, and 26 did not respond to PPI therapy. Twenty-four-hour pH impedance recordings were analyzed for fasting and prandial air swallows and reflux characteristics, including the presence of gas in the refluxate. RESULTS: PPI-refractory patients had a higher number (83.1 ± 12.7 vs 47.8 ± 7.3, P < .05) and rate (10.5 ± 1.4 vs 5.9 ± 0.8/10 minutes, P < .05) of prandial air swallows than patients who responded to PPI therapy; they also had a higher number (25.5 ± 4.0 vs 16.8 ± 3.3, P < .05) and proportion (70% ± 0.03% vs 54% ± 0.06%, P < .05) of postprandial, mixed gas-liquid reflux. Symptoms of PPI-refractory patients were more often preceded by mixed gas-liquid reflux events than those of PPI responders. Fasting air swallowing and other reflux characteristics did not differ between patients who did and did not respond to PPIs. CONCLUSIONS: Some patients with GERD who do not respond to PPI therapy swallow more air at mealtime than those who respond to PPIs and also have more reflux episodes that contain gas. These factors, combined with mucosal sensitization by previous exposure to acid, could affect perception of symptoms. These patients, who can be identified on standard 24-hour pH impedance monitoring, might be given behavioral therapy to reduce mealtime air swallowing.

Central calcitonin exerts anorectic effects via the hypothalamus in chicks.

Calcitonin (CT) causes satiety in mammals, but the mechanisms that mediate this effect are poorly understood. Additionally, there are no reports on CT-induced satiety within the avian class. Therefore, the purpose of this study was to elucidate some of the central mechanisms regulating CT-induced satiety in a non-mammalian vertebrate, the chick. Broiler-type chicks, at 4 days of age, responded to central CT (0.3, 1.0 and 3.0 nmol) with both reduced food and water intake. The effect on water intake was secondary to that of food. An increased number of c-Fos immunoreactive cells were found in hypothalamic nuclei associated with satiety including the arcuate nucleus, dorsomedial nucleus and ventromedial hypothalamus after central CT injection. Increased jumps, distance traveled and time spent perching on food containers were also observed, and these behaviors are likely not competitive with ingestion. Also, central CT injection was associated with reduced food pecks, but increased pecking efficiency. Blockage of corticotrophin releasing factor receptors did not prevent central CT-induced satiety. Central CT appears to be a regulator of satiety in chicks and this effect is likely mediated via interactions within the hypothalamus.