We wished to define the physiology of the canine ileocolonic sphincter (ICS) and to examine function in relation to the region's anatomy. Prolonged recordings of tone at the ICS were made from seven dogs with isolated ileocolonic loops, and the effects of ileal and colonic distension on sphincteric tone were assessed. In acute experiments, pull-through pressures were measured at the ICS, and the location of the high-pressure zone was related to the region's anatomy. Basal tone at the ICS of approximately 30 cmH2O was confirmed; tone was augmented by colonic and ileal distension. The high-pressure zone was always centered on the anatomic ICS, but it extended into the adjacent ileum and colon for a total length of 2.0 cm (range 1.5-3.0 cm). Phasic contractions contributed to the maintenance of tone at the ICS, and a coordinated pattern of phasic contractions appears to contribute to the sphincteric properties of the region.

A series of 500 cholecystectomies performed over a 7-year period was reviewed retrospectively. The reliability of preoperative clinical features such as jaundice and pancreatitis was assessed in determining the presence of choledocholithiasis, and was found to be of limited value. Investigations such as intravenous cholangiography and liver function tests were found also to be inaccurate in the detection of common duct stones as was the appearance of the duct at operation. The usefulness of the peroperative cholangiogram in the detection of common duct stones that would otherwise have been overlooked is emphasized. Common duct stones would have remained undetected in 25 per cent of patients with choledocholithiasis. Despite the use of routine peroperative cholangiography common duct stones were overlooked in 11.25 per cent of patients who underwent exploration.

We wondered whether Roux gastrojejunostomy alone or with intestinal pacing would slow gastric emptying and ameliorate the dumping syndrome after truncal vagotomy and subtotal distal gastrectomy. In five conscious dogs with vagotomy and distal gastrectomy, the Roux loop alone slowed gastric emptying of 100 ml 5% glucose instillates, but not of 100 ml 25% glucose instillates, while pacing the loop backwards slowed emptying of both. Pacing also decreased the postcibal hemoconcentration and hyperglycemia found after the 25% instillates. However, pacing did not alter the postprandial hyper-GIP-emia (gastric inhibitory peptide) and hyperinsulinemia found in Roux gastrectomy dogs, suggesting that pacing worked by slowing emptying of glucose rather than by releasing enteric hormones. Although pacing did not stimulate jejunal action potentials (contractions), the greater the number of action potentials occurring during pacing, the more the slowing (r = .738, p less than .001). We concluded that the combination of Roux gastrojejunostomy and pacing ameliorated postgastrectomy dumping in dogs. The tests provide a basis for treating humans with postgastrectomy dumping.

The ileal pouch-anal anastomosis improves clinical results after colectomy and mucosal proctectomy compared to the straight ileoanal anastomosis. The question was what physiologic changes brought about by the pouch led to the improvement. Among 124 patients who had had ileoanal anastomosis, 25 volunteered for a detailed clinicophysiologic evaluation. Fourteen had had the ileal pouch-anal operation a mean of 8 months previously, and 11 had the straight ileoanal operation a mean of 25 months previously. Both groups of patients had satisfactory anal sphincter resting pressures (mean +/- SEM, pouch = 68 +/- 8 cm H2O, straight = 65 +/- 9 cm H2O, p greater than 0.05) and neorectal capacities (pouch = 278 +/- 26 ml, straight = 233 +/- 36 ml, p less than 0.05), and all could evacuate spontaneously. However, the pouch patients had a more distensible neorectum (delta V/delta P pouch = 9.5 +/- 1.3 ml/cm H2O, straight = 4.9 +/- 0.9 ml/cm H2O, p less than 0.05) and smaller amplitude neorectal contractions (pouch = 36 +/- 5 cm H2O, straight = 90 +/- 13 cm H2O; p less than 0.05). We concluded that the pouch-anal anastomosis increased the distensibility of the neorectum and decreased its propulsive drive, and so improved clinical results.