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Biomedical subjects

A W Hall

Publications and source records attributed to A W Hall.

At least 37 records · Page 2Linked to original sources
PubMed1978

Effect of gastrointestinal hormone infusions of lower oesophageal competence of rhesus monkeys.

The lower oesophageal high pressure zone (HPZ) was studied in 5 non-refluxing and 3 refluxing Rhesus monkeys. The changes in HPZ and reflux status in response to infusion of various doses of secretin, cholecystokinin and glucagon were measured in all animals, and, in the 5 non-refluxing monkeys, after oesophagogastrectomy with replacement of the lower oesophagus by a stomach tube. All three hormones consistently produced a transient decrease in the HPZ pressure. The only change in response following oesophagagastrectomy and gastric tube replacement was a significant delay in the response to each hormone. Neither hormone infusion nor operation altered gastro-oesophageal reflux status. It appears that lower oesophageal competence in primates is more dependent on the presence of narrow, muscular, intra-abdominal tube than on a specialized segment of the lower oesophagus.

Animals↗
PubMed1978

Value of laparoscopy in the diagnosis and management of pancreatic carcinoma.

Our experience with laparoscopy in the diagnosis and staging of 23 cases of pancreatic cancer is reported. This endoscopic procedure has proved useful in the diagnosis of the disease, in the assessment of operability, and in the retrieval of material for histological and cytological confirmation of pancreatic cancer. An infra-gastric laparoscopic method for inspection of the body and tail of the pancreas is described and the technique may allow the earlier detection of neoplasms in this region.

Adult↗
PubMed1977

The effect of small bowel resection and subsequent precise antrectomy on lower esophageal function in rhesus monkeys.

The lower esophageal high pressure zone (HPZ) was characterized manometrically and reflux status determined in eight male rhesus monkeys. The studies were repeated six weeks and six months after 50 per cent distal small bowel resection. At the same time fasting serum gastrin and gastric inhibitory polypeptide values were assayed. In seven animals precise antrectomy with gastroduodenal anastomosis was performed and the studies repeated. HPZ pressure increased from 6.7 +/-0.67 mm Hg (+/-1 SEM) to 10.3 +/- 0.76 mm Hg at six weeks (p less than 0.005). At six months the pressure was 9.3 +/- 1.02 mm Hg (p less than 0.02) and after antrectomy 15.2 +/- 3.1 (not significant from 6 month value, p less than 0.02 from control). Serum gastrin and GIP values showed significant elevations at six weeks, but six month and postantrectomy results were not statistically different from control. Reflux episodes for the group were reduced at six weeks and six months. After antrectomy increased reflux was noted.

Animals↗
PubMed1977

Effect of 50% distal small bowel resection on gastric emptying in Rhesus monkeys.

The effect of bowel resection, sufficient to cause gastric secretory changes, on gastric emptying is unknown. Gastric evacuation was characterized in 8 Rhesus monkeys by a modification of George's double sampling test meal. Fifty per cent distal small bowel resection was then performed. Gastric emptying was again studied at 6 weeks and 6 months. The rate constant fell from -0.00289 +/- 0.000467 (+/-1 SEM) to -0.00232 +/- 0.00106 during the early phase, but role to -0.00308 +/- 0.00186 by 6 months, neither value being statistically different from the preoperative values. T1/2 rose from 125.2 +/- 19.2 mins to 367 +/- 173.4 mins by 6 weeks and to 380.9 +/- 161.6 mins by the end of the experiments. Corresponding values for T were: control period 425.8 +/- 63.2 mins, early phase 1223 +/- 589 mins and late phase 1245.9 +/- 529.6 mins. None of these changes were statistically significant. Alterations in emptying time within each animal were consistent at the two postoperative phases. Although the two animals showing acceleration of evacuation were those with least change in secretion, compensation for the observed increase in output of gastric juice did not materially alter the results.

Animals↗
PubMed1977

Evaluation of a new monkey model for the repeated study of bile secretory physiology.

An unchaired monkey model for the repeated long-term study of biliary secretory physiology is reported. Postoperative management with cholre recorded. Evaluation was performed by repeated measurement, over a period of months, of bile flow and 14C erythritol clearance at three rates of taurocholate infusion given intravenously in a random order. Response to secretin was tested at the final infusion rate of taurocholate for each experiment. The outcomes of 9 monkeys were described of which 5 were repeatedly studied. They demonstrated an increase in bile flow and 14C erythritol clearance with increasing bile salt output. A dramatic choleresis over a wide range of bile salt excretion was noted with secretin and a linear relationship between bile bicarbonate output and bile salt secretion rate was observed. The new model has several major advantages and gives higher bile flows than previously recorded in the chaired model.

Animals↗
PubMed1977

Effect of antrectomy on gastric hypersecretion induced by distal small bowel resection.

Seven male Rhesus monkeys, with demonstrated gastric hypersecretory response to 50% distal small bowel resection, were studied. This increase in gastric acid output had persisted for more than 6 months. Precise, anatomical antrectomy without vagotomy was performed and intestinal continuity restored by gastroduodenostomy. Complete abolition of basal acid secretion and of the secretory response to histamine occurred. These effects could not be reversed by continuous (5 hour) infusions of pentagastrin at 0.2 microgram/kg hr-1 or 2 microgram/kg hr-1. The dose response curve to gastrin pentapeptide was altered; maximum secretion was greatly reduced and occurred at 10 microgram/kg hr-1. Neither basal serum gastrin or basal serum GIP was significantly reduced by antrectomy. These findings indicate that in this animal model the antrum is essential in the genesis of the hypersecretory state. If these findings are relevant to man precise antrectomy may be the procedure of choice for symptomatic acid hypersecretion after small bowel resection or disease.

Animals↗
PubMed1976

Functional evaluation of the interposed colon as an esophageal substitute.

Five Rhesus monkeys and four human adults with colonic reconstruction of the esophagus have been studied by manometric, fluoroscopic and reflux tests. Transit through the graft is mainly under the influence of gravity. Infrequent colon contractions can be propulsive, and sequential haustral contractions give the appearance of peristalsis. The diaphragmatic hiatus and esophagocolic anastomosis are the sites of weak barriers to reflux which are readily overcome by abdominal compression and gastric distension. Esophageal peristalsis is necessary to return refluxed material and cricopharyngeus muscle is the final barrier to regurgitation.

Adult↗
PubMed1976

Patterns of gastroesophageal reflux in health and disease.

Twenty-four pH monitoring the distal esophagus quantitates gastroesophageal reflux in a near physiologic setting by measuring the frequency and duration of acid exposure to the esophageal mucosa. Fifteen asymptomatic volunteers were studies with 24-hour pH and esophageal manometry. The normal cardia was more competent supine than in the upright position. Physiologic reflux was unaffected by age, rarely occurred during slumber, and was the rule after alimentation. One hundred symptomatic pateitns with an abnormal 24-hour pH record (2 S.D. above the mean of controls) could be divided into three patterns of pathological reflux: those who refluxed only in the upright position (9), only in the supine position (37), and in both positions (54). Upright differed from supine refluxers by excessive aerophagia causing reflux episodes by repetitive belching. Compared to controls, they had excessive post-prandial reflux, lower DES pressure, and less DES exposed to the positive pressure of the abdomen. Supine differed from upright refluxers by having a higher incidence of esophagitis and an inability to clear the esophagus of acid after a supine reflux episode. Compared to controls, they had only a lower DES pressure. Combined refluxers had a higher incidence of esophagitis than supine refluxers. Stricture (15%) was seen only in this group. They were similar to supine refluxers in their inability to clear a supine reflux episode. Compared to controls, they had a lower DES pressure and less DES exposed to the positive pressure of the abdomen. Forty of the 100 patients had an antireflux procedure (4 upright, 8 supine, 28 combined). The most severe postoperative flatus and abdominal distention was seen in the upright refluxers. It is concluded that minimal reflux is physiological. Patients with pathological reflux all have lower DES pressure. Patients with upright reflux have less of their DES exposed to the positive pressure environment of the abdomen. Patients with supine reflux have an inability to clear the esophagus of reflux acid and are prone to develop esophagitis. Patients with both upright and supine reflux have the most severe disease and are at risk in developing strictures. In patients with only upright reflux, aerophagia and delayed gastric emptying may be an important etiological factor.

Deglutition Disorders↗
PubMed1976

Effect of fifty percent small bowel resection on gastric secretory function in rhesus monkeys.

Basal acid output (BAO) and histamine-stimulated acid output (MAO) were studied in 11 fasting rhesus monkeys. Serum gastrin and gastric inhibitory polypeptide (GIP) were assayed in eight. Fifty percent distal small bowel resection was performed and the studies were repeated at 6 weeks and 6 months. Highly significant increases were seen in BAO (0.37 "/- 0.05 to 1.73 +/- 0.37 mEq. per hour; P less than 0.005) and MAO (1.7 +/- 0.22 to 3.21 +/- 0.45 mEq. per hour P less than 0.01) at 6 weeks. These levels persisted at 6 months. The ratio BAO:MAO increased throughout the experiment, the changes being significant at both time intervals. A significant rise was noted in the levels of both fasting serum gastrin (P less than 0.05) and GIP (P less than 0.01) during the early phase. By 6 months the levels of both hormones had fallen and were not significantly different from the control values. It was concluded that 50 percent small bowel resection causes a persistent increase in gastric acid secretion. No corresponding sustained change in serum gastrin or GIP occurs.

Animals↗
PubMed1975

The continuing challenge of gallbladder cancer. Survey of thirty years' experience at the University of Chicago.

The current concepts of the etiologic factors and spread of carcinoma of the gallbladder are discussed. The experience at the university of Chicago with this condition over a period of thirty years is reviewed. Of eighty-two cases diagnosed during this time, 88 per cent of the patients died within one year of diagnosis and the five year survival rate was 5 per cent. The difficulties in diagnosis of cholecystic neoplasms are considered, and the possibility of increasing diagnostic accuracy by the use of celiac axis angiography, immunologic tests for tumor-associated antigens, peptide hormone assays, and cytologic study of duodenal juice is discussed. The place of palliative surgery in the management of cancer of the gallbladder is outlined. Means of improving the current high mortality of this condition are evaluated, and a plea is made for a controlled trial of the various forms of treatment that have been suggested.

Adult↗