Jerry F. Schlegel

Pressure profile of the rectum and anus of healthy persons

SummaryThis study was undertaken to determine the pressure profile of the rectum and anal sphincter of healthy persons. Open-tip tubes and tiny balloons of various sizes connected to pressure transducers were withdrawn in stages from the lower part of the sigmoid to the exterior in 11 healthy males in the Sims position. Records of the pressures encountered during the withdrawals were made photokymographically. Mean sigmoid and rectal resting pressures were 2 to 5 cm. of water above ambient pressure. A band of elevated pressure about 4 cm. in width was always detected in the anal sphincter. The mean maximal pressure in the sphincter as detected by open-tip tubes was 45 cm. of water; greater maximal pressures were encountered when balloons were withdrawn through the sphincter. Bands or zones of increased pressure were consistently detected in the rectum during withdrawal of even tiny balloons. These zones have been interpreted as being produced by pressure applied to the balloon as it was withdrawn past a bend in the rectum or over folds in the rectum. The suggestion is made that these structures may act as incomplete or feeble valves resisting the analward movement of rectal contents, just as they resisted the analward movement of the balloons.

The Changes in the Intra-Arterial Pressure during Immersion of the Hand in Ice-Cold Water

The response of the intra-arterial pressure to the cold immersion stimulus was studied in 42 healthy young adults, continuous direct (arterial-pressure) recording being used. The average systolic elevation was 22.6 mm. Hg and the average diastolic elevation was 16.3 mm. Hg. The difference between direct and indirect methods of measuring blood pressure was studied in 351 simultaneous determinations in 35 of these young adults. The direct systolic pressure averaged 9.7 mm. Hg higher and the diastolic pressure was 7.3 mm. Hg lower than the indirect measurement.

The pressure profile of the gastroduodenal junctional zone in dogs

EDITORIAL SYNOPSIS A narrow zone of raised pressure has been found at the gastroduodenal junction in fasting dogs, indicating that the diameter of the lumen is less than 1-7 mm. most of the time. Instillation of acid into the duodenum increased the pressure in the junctional zone and stimulated duodenal motility while antral motility decreased. Instillation of olive oil into the duodenum also increased the pressure at the junction but only after a lapse of 15 minutes whereas antral motility was inhibited immediately.

Identification of the Gastroesophageal Mucosal Junction by Transmucosal Potential in Healthy Subjects and Patients with Hiatal Hernia

Summary The purpose of this investigation was to determine whether the contrasting transmucosal potentials of the stomach and the esophagus can be used to identify the gastroesophageal mucosal junction. To relate changes in the potential difference (PD) to other characteristics of the junctional zone, pressure and pH determinations were made simultaneously with those of PD. Observations were made during fasting on 18 healthy persons, 5 dogs, and 12 patients with hiatal hernia. A zone of elevated pressure was found at the junctional region in the healthy persons and the dogs. The PD changed within the region of elevated pressure. The greatest change was at the physiologic hiatus (site of respiratory reversal) or just distal to it. The pH in the healthy persons and the dogs usually changed within the zone of elevated pressure, and, as with PD, the greatest change usually occurred just distal to the point of respiratory reversal. In some tests, an acid pH extended into the esophagus. When the gastroesophageal junction was visualized in an anesthetized dog with the exploring electrode previously fixed at the site of maximal change in PD, the electrode was found within 5 mm of the mucosal junction. Pressure characteristics indicative of hiatal hernia were detected in the 12 patients known to have hiatal hernia. In these patients, the site of greatest change in PD was shifted to the proximal region of the zone, indicating displacement of the mucosal junction into the chest. An acid pH in the esophagus was common in the patients with hiatal hernia.

The Effect of Sympathectomy, Vagotomy, and Oesophageal Interruption on the Canine Gastro-oesophageal Sphincter

The nature of the control of the gastrooesophageal sphincter is obscure. It has been thought to be under the regulation of the autonomic nervous system so that through the influences of the vagus and sympathetic nerves the resting tone is maintained and relaxation and contraction are initiated. Beyond this broad generalization, however, there is considerable divergence of opinion as to the precise function of the various nervous elements and their interrelationships. The purpose of this investigation was to determine the effect of certain nerve and oesophageal interruption procedures on the resting tone of the sphincter and its relaxation and contraction during swallowing.

Gastric bicarbonate appearance with ethanol ingestion. Mechanism and significance.

Increasing quantities of HCO3− appeared in the stomach and in gastric pouches of conscious dogs with gastric infusion of increasing concentrations of ethanol. HCO3− appearance was closely correlated with gains of K+ and of glucose to the contents and with reductions in transmucosal potential differences, each of which is associated with increased mucosal permeability. We concluded that increased diffusion of HCO3− through a more permeable mucosa accounted for the appearance of HCO3− with the lower concentrations of ethanol we used (5–20%) and that bulk movement of the interstitial fluid into the contents added to HCO3− entry with the most damaging, desquamating, concentration (40%). With the gastric contents at 100 mM HCl, an unstirred layer of mucus gel over the mucosa would need to be of greater depth than previous estimates to produce mucosal surface neutrality at the rates of HCO3− appearance we observed. However, faster rates of HCO3− production combined with an unstirred layer could provide significant protection to the gastric mucosa.

The effect of denervation on feline esophageal function and morphology

Abstract Denervation of the feline esophagus leads to a severe motility disorder which is different from that recorded after denervation of the dog and monkey esophagus. Bilateral cervical vagotomy resulted in complete paralysis of the body of the esophagus, but peristalsis returned to that portion composed of smooth muscle. Esophageal dilatation occurred, and the incidences of relaxation and contraction of the inferior sphincter in response to swallowing were markedly reduced. These sphincteric abnormalities returned to normal after 6 months, but those in the body of the esophagus were unchanged for periods of 9 months. Esophageal dilatation occurred after vagotomy in all cats. Esophagomyotomy did not prevent this. Periesophageal vagotomy had a very inconstant effect. Sympathectomy had little effect on esophageal motility but caused marked diminution in the resting pressure of the inferior sphincter. When combined with vagotomy, sympathectomy prevented the effect of vagotomy on the sphincter but not on the body of the esophagus. None of these procedures induced a loss of ganglion cells in Auerbachs plexus.

Electric and motor activity of innervated and vagally denervated feline esophagus

Motor and electric activities of the feline esophagus were detected before and after vagotomy by use of intraluminal pressure detectors and chronically implanted platinum electrodes. These were placed in the midesophagus (E1), at the three-quarter point (E2) and in the lower 2 cm (E3). Both inner and outer layers of muscle were skeletal at E1 and smooth at E3, whereas at E2 the outer layer was predominantly skeletal and the inner predominantly smooth. Before vagotomy, contractions of the skeletal muscle fibers of the midesophagus were associated with pressure changes and action potentials of lesser amplitude, briefer duration and faster propagation than those of the smooth muscle fibers of the lower esophagus. The frequency of the skeletal muscle action potentials was greater than 25 cycles per second (cps), and that of the smooth muscle action potentials was less than 25 cps. The first recorded event during peristalsis was orad movement of the electrodes due to contraction of longitudinal fibers. After vagotomy, action potentials occurred with nearly every stimulation, but the incidence of intraluminal pressure increases was reduced. Repetitive responses were common. Action potentials with frequencies faster than 25 cps were eliminated in the lower quarter of the esophagus were orad movement of electrodes was also abolished owing to paralysis of longitudinal muscle fibers. The incidence of peristalsis was reduced during the first month after vagotomy to between 33 and 44% of responses, but thereafter its occurrence improved to 40 to 80% of responses. The predominant electromotor features of the period after vagotomy were persistent weakness, incoordination and repetitive responses in the lower esophagus, which prevented normal emptying of the organ.

Electrical activity of the canine esophagus and gastroesophageal sphincter: its relation to intraluminal pressure and movement of material.

Myogenic electrical activity of the sphincter and adjacent esophagus and stomach was detected by the chronic implantation of bipolar silver/silver chloride electrodes. Action potentials occurred in the esophagus following deglutition and were synchronous with the peristaltic contractions detected from within the lumen. Continuous phasic activity was present in the gastroesophageal sphincter and the adjacent gastric fundus. Reduction of the continuous phasic electrical activity occurred in the sphincter with relaxation. Reduction of it also occurred in the fundus with distention of the esophagus or stomach and during anesthesia. With swallowing, sphincteric action potentials, related to sphincteric contraction, followed the inhibition of phasic activity in the orad segment of the sphincter, while only inhibition of phasic activity and its return occurred in the caudad segment. Esophageal distention caused inhibition of action potentials in the esophagus distal to the distention as well as inhibition of the sphincteric continuous phasic activity. The inhibition continued until the distention was terminated. After subhilar bilateral vagotomy, intraluminal pressures and myogenic action potentials were simultaneous and of lesser magnitude in the vagotomized segment of the esophagus. The motor action of the gastroesophageal sphincter was not altered by vagotomy but the incidence of response to swallowing was reduced by about 50%.

Pressure and Potential Difference Characteristics of Surgically Created Canine Hiatal Hernia

Summary Small hiatal hernias were made in four dogs, large hernias were made in five dogs. Roentgenological, manometric, electrical potential difference studies were done before and after operation. In dogs with hernia, the zone of increased pressure between the abdominal stomach and the esophagus was elongated and at times showed more than one respiratory reversal and two peaks of pressure with an intervening plateau. The observations confirm the usefulness of these pressure abnormalities in the diagnosis of hiatal hernia in human beings. Acute observations in dogs with and without hiatal hernia demonstrated that the site of maximal change in potential difference was at, or within, a few millimeters of the gastroesophageal mucosal junction. Displacement of the point of greatest change in potential difference from the middle of, or distal part of, the zone of elevated pressure into the proximal half of the zone and particularly to its orad extremity was confirmed as a characteristic of hiatal hernia. Reflux was demonstrated roentgenographically in all dogs with small hernia and in all but one dog with a large hernia. In small hernias, reflux occurred only when the sphincter relaxed as a consequence of deglutition or distension of the lower esophagus. Spontaneous reflux occurred in dogs with large hernia. Thus, displacement of the sphincter into the chest reduces the ability of the sphincter to prevent reflux.