Intestinal tone and gas motion

The intestine propels and evacuates large gas loads without detectable phasic contractions by manometry. We hypothesized that intestinal gas motion is produced by changes in gut tone and capacitance. In 13 healthy subjects, changes in duodenal tone were measured by a barostat during continuous perfusion of lipids (Intralipid, 1 kcal min(-1)) into the duodenum for 60 min. In separate groups, the effects of jejunal gas infusion (N2, CO2 and O2 in venous proportions at 12 mL min(-1) starting after 15 min lipid perfusion) and sham infusion were tested. Gas outflow was collected continuously via an intrarectal cannula. Duodenal lipid perfusion produced a rapid duodenal relaxation (volume increased by 48 +/- 18%; P < 0.01 vs basal). Gas infusion increased gas evacuation (184 +/- 59 mL), and this was associated with a tonic contraction of the duodenum (R = 0.86; P < 0.01) that completely reverted the lipid-induced duodenal relaxation (volume decreased by 42 +/- 13%; P < 0.05). During sham infusion only 52 +/- 28 mL of gas were evacuated (P < 0.05 vs gas infusion), and the duodenum remained relaxed due to the effect of lipids (0 +/- 1% volume reduction; ns). In conclusion, intestinal gas propulsion and clearance is associated with a tonic contraction of the gut wall and reduced gut capacitance.     

Irritable bowel syndrome in childhood: visceral hypersensitivity and psychosocial aspects

Abstract Visceral hypersensitivity is often considered to play a major etiologic role in the pathophysiology of irritable bowel syndrome in adults, and some authors argue that this increased sensitivity is mainly due to psychological factors. In contrast, there are no data in children with irritable bowel syndrome which confirm this relationship. The aim of the study was to evaluate the relationship between psychosocial aspects and sensorymotor function in children affected by irritable bowel syndrome. Ten children fulfilling the Rome II criteria for irritable bowel syndrome and seven healthy controls were enrolled. We studied the thresholds and the perception of visceral stimuli in the rectum by means of an electronic barostat (isobaric phasic distentions, 3 mmHg/1 min, interval 1 min) and a validated questionnaire. Personality features were evaluated by means of the Big Five Questionnaire for Children. Sleep, mood disturbance, anxiety and individual performance (missed school days, school results and social activities) were also evaluated. Children with irritable bowel syndrome showed significantly lower thresholds for discomfort (14.8 ± 3.5 vs 22.3 ± 6.9 mmHg, P = 0.010) and a higher cumulative perception score (28.2 ± 11.1 vs 12.3 ± 8.0, P = 0.005) compared with healthy controls. A higher emotional instability (57.8 ± 7.0 vs 48.7 ± 10.1, P = 0.047), sleep disturbance (7.2 ± 1.0 vs 9.3 ± 0.5, P = 0.004) and anxiety (6.3 ± 2.0 vs 2.3 ± 1.7, P = 0.009) were observed in irritable bowel syndrome patients. Moreover, in a multivariate analysis, the cumulative perception score was significantly related to emotional instability (P = 0.042). In conclusion children with irritable bowel syndrome exhibit visceral hypersensitivity and psychosocial impairment. Emotional instability, as a personality feature in these children, seems to modulate the perception response to visceral stimulations.     

Proximal stomach function in obesity with normal or abnormal oesophageal acid exposure

There is an increased prevalence of gastro-oesophageal reflux and symptoms in obese patients. Information about the proximal stomach in obese patients with reflux is lacking. Gastric volume and compliance are similar between obese and lean subjects. To study the proximal stomach function and perception in obese patients with normal or abnormal oesophageal acid exposure, thirty-one obese patients, with normal or abnormal oesophageal acid exposure, underwent medical evaluation of oesophageal and gastrointestinal symptoms by a questionnaire and measurement of proximal stomach function and perception by an electronic barostat and a standardized questionnaire. Nineteen obese patients had abnormal oesophageal acid exposure. The percentage of total time with pH <4 is significantly related to the presence of hiatal hernia, the oesophageal intensity-frequency symptom score and gender, i.e. higher percentage in men. The perception cumulative score was significantly different between patients with normal and abnormal oesophageal acid exposure after adjusting for covariates (gender, body mass index, age, minimal distending pressure, gastric tone and gastric compliance). Gastric tone and compliance were significantly related to the perception cumulative score. In conclusion, patients with abnormal oesophageal acid exposure have increased gastric perception. A significant relation among gastric tone, gastric compliance and upper gastrointestinal sensations was shown.