Search PubMed⌕ Search

Biomedical subjects

D L Wingate

Publications and source records attributed to D L Wingate.

At least 109 records · Page 6Linked to original sources
PubMed1981

Fasting motor activity occurs during a day of normal meals in healthy subjects.

Using a radiotelemetric technique of pressure recording which did not interfere with normal feeding, jejunal motor activity was recorded in seven healthy human subjects, who were given three hospital meals during the course of a day, and allowed ad libitum supplementary snacks. Fasting motor activity was detected during the day in five subjects, and, although its occurrence was very variable, tended to occur shortly before the next meal.

Adult↗
PubMed1980

Normal patterns of human upper small bowel motor activity recorded by prolonged radiotelemetry.

In order to characterise human interdigestive cyclical motor activity, and its interruption by food, jejunal pressure changes in healthy volunteers were recorded continuously for 24 hours, using an ingested pressure-sensitive radiotelemetry capsule tethered at the duodenojejunal flexure. In 20 studies, the subjects fasted throughout; in another 20 studies they received a single standard meal. Using this technique, fasting motor complexes were easily detected. There was considerable variation in interdigestive cycle duration and in the interruption caused by food. The data were not normally distributed. The study indicates that any descriptions of 'atypical' jejunal motility patterns must take into account the wide variations seen in health, before they can be regarded as representing dysfunction or disease.

Adult↗
PubMed1978

The logical analysis of the electroenterogram.

Simple--and inexpensive--logic circuitry is described which will discriminate three types of spike activity in the canine electroenterogram. Used during high-speed replay of tape-recorded myoelectric activity, it provides a numerical analysis of the duration and spike content of the three types of activity, without the need for sophisticated (and costly) computer analysis. The ability of the analyzer to detect types of activity is illustrated by the analysis of the effects of a peptide hormone infusion on the canine electroenterogram. The device might also serve as the prototype for other applications in which simple digital logic could be used to detect different patterns in continous analog signals.

Animals↗
PubMed1978

Quantitative comparison of the effects of cholecystokinin, secretin, and pentagastrin on gastrointestinal myoelectric activity in the conscious fasted dog.

The effects on gastrointestinal myoelectric activity of infused pentagastrin, cholecystokinin (CCK), and secretin at physiological doses were studied in live dogs with implanted serosal electrodes during 56 six-hour studies. Pentagastrin dose-dependently increased gastric and duodenal slow-wave frequencies; secretin and CCK did not. Pentagastrin and CCK diminished the incidence of fasting migrating myoelectric complexes (MMCs), but MMCs were abolished only in the proximal small intestine. Pentagastrin infusion was not reflected in an increased number of spikes, whereas CCK induced a dose-dependent increase in jejunal spike activity. Secretin dose-dependently decreased duodenal and jejunal spike incidence without a marked effect on MMC incidence. Analysis of patterns of spike activity showed significant dose-dependent changes with all three peptides. The different effects of pentagastrin and CCK on spike activity in these studies may have been a consequence of pentagastrin-stimulated gastric acid secretion. None of the three peptides produced a pattern of myoelectric activity which closely resembled that seen on feeding; since, unlike food, all three peptides had little or no effect on the distal small intestine, it seems unlikely that combinations of these peptides are responsible for the change induced by food. The failure of these peptides to abolish fasting patterns in the distal intestine suggests a possible mechanism for some types of post-vagotomy dysfunction.

Action Potentials↗
PubMed1977

The gastrointestinal myoelectric response to 13-Nle-motilin infusion during interdigestive and digestive states in the conscious dog.

Gastrointestinal myoelectric activity was studied in three conscious fasted dogs with electrodes surgically implanted in the stomach and small intestine, during separate and combined intravenous infusions of 13-norleucine motilin (13-nle-motilin) and pentagastrin (PG). Basal recordings confirmed the presence of regular interdigestive myoelectric complexes (MC's). 13-nle-motilin infusion below 50 ng/kg-h was without effect: higher doses up to 400 ng/kg-h resulted in the interpolation of one or more MC's in the spontaneous sequence. The rate of aboral transit of 13-nle-molitin-induced MC's did not differ significantly from that of spontaneous MC's. When MC's were abolished by feeding or PG infusion, simultaneous 13-nle-motilin administration was without effect on spike activity, but slightly attenuated the accelerating effect of gastrin on the gastric pacemaker frequency. The myoelectric events triggered by 13-nle-motilin suggest that in the conscious dog the polypeptide may not act directly on the smooth muscle cell, as it does in vitro, but through an extra-enteric neural control mechanism which is uncoupled by gastrin.

Aminocaproates↗
PubMed1976

Motilin-induced electrical activity in the canine gastrointestinal tract.

Myoelectric activity induced by a synthetic analogue of the duodenal polypeptide motilin, was studied in isolated vascular-perfused canine duodenum and stomach, and in conscious dogs with serosal electrodes implanted in the stomach and the small intestine. In the isolated preparation, the duodenum was found to be four times as sensitive as the antrum to the polypeptide, showing a dose-dependent increase in spike activity within two minutes after administration of the polypeptide. By contrast, in the conscious fasted animal, the only response to motilin, above a threshold dose, was the interpolation of a premature migrating myoelectric complex in the spontaneous interdigestive sequence, appearing fifteen to twenty minutes after the start of infusion. Since the essential difference between the ex vivo and the intact intestine was the preservation of efferent and afferent nervous connections in the latter, it seems that in the conscious animal, the response to exogenous motilin is modulated by the innervation of the intestine, or, alternatively, motilin interacts with the centre controlling the pattern of motor activity in the small intestine rather than directly with smooth muscle. The latter hypothesis is supported by the observation that motilin had no effect on the motor activity of the small intestine during the infusion of pentagastrin which abolishes spontaneous migrating myoelectric complexes.

Action Potentials↗
PubMed1976

Effects of 13-nle-motilin on the electrical and mechanical activity of the isolated perfused canine stomach and duodenum.

Synthetic 13-norleucine-motilin (13-nle-motilin), structural and biological analogue of the naturally-occurring duodenal polypeptide, motilin, is known to stimulate antral and duodenal motor activity in vitro, but delays gastric emptying in man. In this study the direct actions of the synthetic polypeptide on myoelectrical activity and intraluminal pressure have been studied in the isolated vascular-perfused canine stomach and duodenum. 13-nle-motilin increased intraluminal pressure in the pylorus and duodenum, and dose-response analysis showed the duodenum to be twice as sensitive as the pylorus to the polypeptide. Pressure changes in the antrum were small and not dose-related, but, whereas the basic electrical rhythm in the duodenum was not altered, slow wave frequency, rhythm, and propagation in the antrum were disturbed. Electronic analysis of the duodenal spike increase which accompanied pressure rises demonstrated correlations between increases in spikes, intraluminal pressure, and dose. These results show that the direct effect of the polypeptide on adjacent organs may explain the combination of increased motor activity with delayed gastric emptying as a consequence of disturbance in the co-ordination between antrum, pylorus, and duodenum.

Animals↗