Diameter and Wall Thickness Recording of Canine Pylorus with Implantable Miniature Ultrasonic Transducers

Abstract

Outer diameter and thickness of the muscular wall of canine pylorus were measured simultaneously by determining the distance between pairs of implanted ultrasonic transducers, evaluating the sonic transit time with a digital sonometer. For the study of the motility in the gastroduodenal transit zone, the ultrasonically determined pyloric responses were compared with signals from conventional strain-gauge transducers sutured to the neighboring duodenum and gastric antrum. After stimulation of the gastrointestinal motility by an intravenous bolus injection of cholecystokinin octapeptide, pyloric contractions with a frequency of 5.2 min-¹ could be recorded for some minutes; those contractions were independent of the more rapid antral and duodenal motility. Together with the observed tonic constriction of the pyloric ring, which could be inhibited by intravenous injection of adrenaline, an autonomous role of the gastroduodenal junction as a true sphincter is supported.

Gastrointestinal Motility During Cardiopulmonary Bypass: A Sonomicrometric Study

“…For the gastrointestinal system, there are only limited reports in literature using sonomicrometry to study gut motility. In an earlier study, the sonomicrometric technique had been applied to study the motility of canine pylorus (13). However, due to the irregular movement of the gut and the lack of appropriate analytical software to remove the recorded artifacts, there was hardly any progress in using this technique until recently, when Adelson and coworkers reported their experimental work in rats (14).…”

“…One of its main features is to record the shortening of myocardial segment length during heart movement during which a pair or several pairs of echo crystals are imbedded in the myocardium to access the distance of two relevant points over the elapsed time. With this principle, sonomicrometry has also been suggested to be used for monitoring the gastrointestinal motility in a rat model (13,14). In this study, we sought to explore the feasibility of using the sonomicrometric technique in a large animal model to either qualify or quantify the movement of the gastrointestinal tract during CPB.…”

A review of the physiology of the canine digestive tract related to the development ofin vitrosystems

“…Besides the effects of the food, motility (Prove & Ehrlein, 1982;Azpiroz & Malagelada, 1984;Mandrek, 1991;Eagon & Kelly, 1993) and hormones (Landor & Wild, 1970;van Kruiningen et al 1987;Patronella et al 1988;Lawson et al 1994;Jin et al 1994a, b) play an important role in the regulation of gastric emptying. Although these parameters are very important, their effects are not discussed in this review because such parameters cannot be used in in vitro models.…”