Biomedical subjects

C Gisolfi

Publications and source records attributed to C Gisolfi.

9 recordsLinked to original sources

PubMed1999

Effects of acute graded exercise on human colonic motility.

Whether physical exercise stimulates colonic motility is unclear. Our aim was to determine the immediate effects of graded exercise on colonic motility. Colonic motility was recorded at six sites in 11 untrained subjects, by colonoscopically placing a solid-state probe. Subjects were free to ambulate. The next day, subjects exercised on a bicycle at 25, 50, and 75% of peak oxygen uptake for 15 min, with each followed by a 15-min rest. Motor patterns, motility indexes, and regional variations before, during exercise, during rest, and during postexercise periods were compared. During exercise, there was an intensity-dependent decrease (P < 0.001) in the number and area under the curve of pressure waves. The incidence of propagated or simultaneous pressure waves and cyclical events also decreased (P < 0.05). After exercise, the pressure activity reverted to baseline, but the number and amplitude of propagated waves increased (P < 0.01), whereas the simultaneous waves and cyclical events remained lower. Acute graded exercise decreases colonic phasic activity. This may offer less resistance to colonic flow, whereas the postexercise increase in propagated activity may enhance colonic propulsion.

Adult↗

PubMed1995

Effect of absorption of D-glucose and water on paracellular transport in rat duodenum-jejunum.

Paracellular transport is thought to be a major absorptive pathway for small nutrient molecules. The authors used in vivo in situ perfusion of rat duodenum-proximal jejunum to examine paracellular transport using lactulose as a probe. They perfused solutions with a constant lactulose concentration but varied initial D-glucose concentration (range 12-176 mM) to open paracellular pathways and to increase water absorption, thereby optimizing potential for paracellular transport of lactulose and other solutes in its molecular weight range. All solutions contained sodium chloride to approach isotonicity. Water absorption was measured as the difference in weight of solution perfused and sample collected. Absorption of D-glucose increased with mean luminal D-glucose concentration, and water absorption more than doubled (from 0.12 +/- 0.03 to 0.26 +/- 0.05 mL/min per g dry wt of segment) as mean luminal glucose concentration was increased from 10 to 80 mM. Lactulose absorption was at the threshold of detection and did not correlate with D-glucose or water absorption. Expressed as percent per segment, D-glucose absorption ranged from 29-50%, and the lactulose absorption rate was 4-5%. The fraction of D-glucose absorption that could be attributed to lactulose absorptive pathways was 12% at the highest rate of water absorption. In conclusion, based on lactulose as a probe, under conditions of opening tight junctions by D-glucose, the paracellular component of D-glucose absorption was of the order of 1/10 of total D-glucose absorption (ie, not a major absorptive pathway.

Animals↗

PubMed1993

Effect of graded exercise on esophageal motility and gastroesophageal reflux in trained athletes.

We evaluated the effect of graded exercise on esophageal motility and gastroesophageal reflux. We studied eight trained cyclists using a catheter with three strain-gauge transducers connected to a solid-state datalogger and an ambulatory intraesophageal pH monitor. Each study lasted 4 hr during which subjects exercised on a stationary bike for 1 hr at 60% of peak O2 uptake (O2 max), 45 min at 75% of O2 max, and for 10 min at 90% of O2 max. Subjects rested 1 hr before exercise (control period) and for 30 min between exercise sessions. Studies were performed after an overnight fast and subjects received only intravenous infusion of 5% glucose solution during the study. Plasma concentrations of gastrin, motilin, glucagon, pancreatic polypeptide (PP), and vasoactive intestinal peptide (VIP) were determined at rest and before and after each exercise session. The duration, amplitude, and frequency of esophageal contractions declined with increasing exercise intensity, and the differences were significant (P < or = 0.05) for all three variables at 90% O2 max. The number of gastroesophageal reflux episodes and the duration of esophageal acid exposure were significantly (P < or = 0.05) increased during exercise at 90% O2 max. Plasma hormone concentrations showed no significant changes between rest and the various exercise sessions. Thus, exercise has profound effects on esophageal contractions and gastroesophageal reflux which are intensity dependent. These effects are not mediated by the hormones measured.

Adult↗

PubMed1991

Effect of exercise on intestinal motility and transit in trained athletes.

We measured the effect of exercise, at different intensities, on duodenojejunal motor activity in eight trained, ambulant cyclists, using a catheter with two strain gauge transducers connected to a solid-state data logger. Orocecal transit time was measured by H2 breath test. Subjects were studied for two consecutive days and fed twice a day with a similar, 860-kcal meal. Control recordings on the first day were made at rest and a naloxone infusion was given after the evening meal. On the second day, the athletes exercised after meals for 20 min at 80% of peak O2 uptake (VO2max) and naloxone was infused during the second session. On separate days, five subjects exercised for 3 h at 60% VO2max and for 10 min at 90% VO2max. Plasma concentrations of beta-endorphin were determined before and after exercise. The fed pattern was interrupted by an activity front during 2 of 16 sessions of exercise at 80% VO2max, in the presence of naloxone, and 5 of 8 sessions at 90% VO2max, with and without naloxone. It was not affected by exercise at 60% VO2max. Orocecal transit was not affected by intense exercise. The results show that exercise can affect intestinal postprandial motor activity. The effect is intensity related and may not be mediated by opioids.

Adult↗

PubMed1982