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Biomedical subjects

W J Dodds

Publications and source records attributed to W J Dodds.

At least 325 records · Page 18Linked to original sources
PubMed1975

Effect of glucagon on esophageal motor function.

This study evaluates the effect of exogenous glucagon on esophageal motor function in man. Manometric studies were performed using an infused catheter system. Resting lower esophageal sphincter (LES) pressure was monitored before and after intravenous pulse doses of glucagon (1 to 100 mug). The effect of glucagon (0 mug ) on esophageal peristalsis was also studied. Multiple blood samples were taken for determination of glucagon, insulin, and glucose concentration. Glucagon effect on LES pressure was also evaluated after LES stimulation by continuous intravenous infusion and pentagastrin (0.04 mug per kg per min). Glucagon caused a transient significant decrease of LES pressure only at pulse doses (20 and 100 mug) which caused nonphysiological elevation of plasma glucagon levels. The temporal profile of decreased LES pressure correlated closely with maximal blood glucagon levels. Glucagon caused no demonstrable change in esophageal peristalsis. During LES stimulation by pentagastrin, glucagon caused significant transient decreases of LES pressure at doses as low as 1 mug per kg. We conclude that glucagon at sufficient dosage has an inhibitory effect on LES pressure. This inhibitory effect is not mediated through changes in serum insulin or glucose and appears to be pharmacological.

Adolescent↗
PubMed1975

Radial distribution of esophageal peristaltic pressure in normal subjects and patients with esophageal diverticulum.

This study was designed to determine the radial profile of peristaltic pressure waves in the esophageal body of normal subjects and patients with isophageal diverticulum. We used a manometric assembly featuring four radial side hole recording orifices oriented at equidistant 90 degree angles. Each recording catheter was infused with water at a rate (6.1 ml per min) which provided high fidelity pressure recording. In normal subjects, the radially recorded peristaltic pressure complexes were similar in peak amplitude and wave form. The range of pressure differences between the four radial recordings averaged 9.0 +/- 4 SD mm Hg A range is less than or greater to 25 mm Hg occurring in 99% of observations. These variations in pressure amplitude showed no consistant spacial orientation. In 5 of the 6 patients with esophageal diverticulum, the range of radial peristaltic pressure differences exceeded 25 mm Hg in the region of the diverticulum, the lowest pressure occurring at the recording orifice facing the diverticulum mouth. In occasional peristaltic sequences abnormal wave forms featuring abrupt onsets or offsets were observed. These bizarre wave forms were probably caused by oralaboral diverticulum movement relative to the recording sensor during peristalsis. Two patients had abnormally high peristaltic pressure amplitudes, greater than 250 mm Hg. This latter finding introduces the possibility that hypertensive peristaltic contractions may contribute to diverticulum production in some patients.

Adult↗
PubMed1973

Movement of the feline esophagus associated with respiration and peristalsis. An evaluation using tantalum markers.

The outer, lateral esophageal walls in the distal half of the esophagus in each of five cats were labeled with small tantalum wires. About 8 wk later, esophageal motion associated with respiration and peristalsis, induced by injecting barium boli (5 ml each) into the proximal esophagus, was recorded on cine and serial biplane roentgenograms while recording intraluminal esophageal pressures simultaneously by manometry. Esophageal motion was also evaluated without a manometric tube in place. The coordinates for each marker were digitized and a computer was used to plot marker position against time. During respiration, the markers passively made a shallow, 2-10 mm excursion on the longitudinal esophageal axis. This movement was synchronous with thoracic and diaphragmatic movement and changes in intraluminal esophageal pressure. Immediately after the onset of peristalsis, the markers made a pronounced oral movement of 10 mm or more above their mean respiratory position, as if to engulf the bolus. Markers in opposing esophageal walls approximated one another and commenced an aboral movement as the bolus tail, which was essentially co-incident with onset of the manometric pressure complex, passed the marker sites. The markers returned to their respective rest positions essentially coincident with passage of the pressure complex peak and then moved below their respective rest positions. The aboral excursion occurred predominantly after the bolus had emptied into the stomach. The magnitude and duration of oral excursion was significantly greater for the distal than for the more proximal markers; conversely, the magnitude and duration of aboral excursion was greater for the proximal than for the more distal markers. During the peristaltic sequence, the labeled portion of the esophagus shortened from 26 to 46% of its resting length. No evidence of esophageal torque was shown. These findings suggest that both the longitudinal and circular esophageal musculature play an active and important role during peristaltic transport of a bolus through the esophagus.

Animals↗