The delivery of lipid to the duodenum has been shown to slow gastric emptying and to increase the resistance to gastric outflow. To investigate mechanisms responsible for these effects, we have recorded antropyloroduodenal motility in nine healthy volunteers during alternate intraduodenal infusions of normal saline and triglyceride emulsion (Intralipid 10%). During the lipid infusions there were reproducible, major changes in the patterns of motility. Pressure waves, apparently isolated to the pylorus, usually started within 10 min of initiation of the lipid infusion. After 20-25 min of lipid infusion these waves occurred at median rates of 2.4 and 2.8/min (1st and 2nd lipid infusions, respectively); these rates were significantly greater (P less than 0.05) than the median rates (all less than or equal to 0.4/min) observed during the equivalent period of the succeeding saline infusions. During 10 of 22 lipid infusions, isolated pyloric pressure waves were associated with sustained pyloric tone. Infusion of lipid into the duodenum suppressed antral pressure waves in all subjects and initiated brief periods of regular duodenal contractions during 11 of 22 infusions. These studies have demonstrated alterations of antropyloroduodenal motor patterns in response to changes in the duodenal luminal content. The effects on antral and pyloric motility are probably of importance in the regulation of transpyloric flow by nutrients in the duodenal lumen.

This study has demonstrated that a 6 week diet with Optifast VLCD results in significant related reductions in liver size and liver fat content. This suggests that the reduction in liver volume is due to loss of fat. The reduction in liver fat and volume likely accounts for the perceived improved operability in patients undergoing LAGB.

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The topography of human pyloric pressure is ill defined, and previous studies of pyloric motility in humans have given conflicting results. A detailed profile of pyloric pressure has been recorded in seven healthy volunteers using a manometric assembly with 13 side holes spaced at 3-mm intervals on reverse aspect of a 3.5-cm long sleeve sensor. After a fasting control period of 40 min, recordings were made for 40 min during intraduodenal infusion of a lipid emulsion. Two major patterns of pressure waves were seen during the fasting control period, namely pressure waves confined to a narrow pyloric zone (isolated pyloric pressure waves) and pressure waves that were less localized and involved the antrum and/or duodenum. During lipid infusion the motility pattern was dominated by isolated pyloric pressure waves and localized pyloric tone. Ninety-two percent of the isolated pyloric pressure waves recorded by the sleeve were recorded by only one or two side holes, consistent with a phasically active zone less than 9 mm in length. Pyloric tone was confined to an even narrower zone and was most often recorded by only one side hole. When both tone and isolated pyloric pressure waves occurred together, they were recorded by the same side holes. By comparison with the side holes, the sleeve recorded 89% of isolated pyloric pressure waves and 98% of nonlocalized waves and recorded pyloric tone with a moderate sensitivity but high specificity. The technical challenge of recording localized pyloric contraction is considerable, and much of the conflict between previous studies of the human pylorus is explicable on methodological grounds.(ABSTRACT TRUNCATED AT 250 WORDS)

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