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Biomedical subjects

R C Heading

Publications and source records attributed to R C Heading.

At least 91 records · Page 5Linked to original sources

Role of motility in the upper digestive tract.

Oesophageal peristalsis is considered in relation to a central regulatory mechanism and circular smooth muscle contraction after cessation of a neural input. The roles of tonic pressure and transient inappropriate relaxation of the oesophageal sphincter in gastro- oesophageal reflux, and the return of refluxed material to the stomach by secondary peristalsis, are examined. Ingested food is accommodated through vagally mediated relaxation of the proximal stomach in response to swallowing. Gastric peristalsis contributes to the disintegration of solids and the regulation of their emptying from the stomach. In humans, vagotomy initially causes marked delay in gastric emptying, but gradual adaptation occurs and peristalsis improves. The movement of fluid across the pylorus is discussed. Duodenogastric reflux is evidently a normal event.

Animals↗

Changes in clinical features of coeliac disease in adults in Edinburgh and the Lothians 1960-79.

From 1960 to 1979 there was a threefold increase in the number of cases of coeliac disease diagnosed annually in adults in Edinburgh and the Lothians. Women accounted for 80% of the increase and their mean age at diagnosis was significantly reduced. The ratio of female to male new cases changed from 1.25 in the '60s to 2.5 in the '70s. In the period 1975-9 56 of 102 adults with coeliac disease presented with no gastrointestinal symptoms, including 30 cases diagnosed as a result of minor biochemical or haematological abnormalities, such as red-cell macrocytosis without anaemia. Over the same period, only 13 presented with a typical malabsorption syndrome compared to 24 of 38 (63%) in the years 1960-4. During 1975-9 58 new cases had no anaemia, compared with eight (21%) in the earlier period. Hypoproteinaemia (concentration less than 60 g/l) and hypocalcaemia of less than 2.00 mmol/l (8 mg/100 ml) were also less common. Though a real increase in the incidence of coeliac disease cannot be discounted, these changes are more likely to be the result of greater awareness of the disease and a lowered threshold for investigation.

Adolescent↗

Vagotomy by chemoneurolysis: an experimental study in the rat.

In the pylorus ligated rat vagotomy has been attempted by chemoneurolysis with alcohol. Surgical truncal vagotomy reduced the intragastric acid produced in a five-hour period from 310 +/- 17.6 (SD) mumol to 5.4 +/- 2.4 mumol with a marked reduction in the ulcer score. Injection of 30% alcohol in the region of the vagal trunks at the level of the lower oesophagus produced a marked reduction in gastric acid secretion (7.6 +/- 3.7 mumol). Injection of solutions of alcohol in concentrations over 10% along the lesser curvature reduced gastric acid output to less than 10 mumol with a corresponding reduction in the ulcer score. Four months after the injection of 30% alcohol along the lesser curvature the acid output was 23.0 +/- 5.7 mumol and no gastric ulceration occurred.

Animals↗

Radionuclide transit studies in the detection of oesophageal dysmotility.

A scintigraphic method is described to measure the transit of a fluid bolus through the oesophagus. Transit times in 16 normal subjects ranged from five to 15 seconds and were highly reproducible. Prolonged transit times were observed in 16 of 19 patients with known oesophageal motility disorders, and in these patients inspection of the time activity curves frequently permitted an adynamic oesophagus to be distinguished from one showing excessive incoordinate contractions. The technique was then applied prospectively to 50 patients referred for oesophageal motility studies and a comparison made between the oesophageal transit measurements and the findings on conventional oesophageal manometry. There was agreement between these tests in 42 (84%) of the 50 patients. The measurement of oesophageal transit may be made quickly and safely, without causing discomfort to the patient, and it appears to be at least as sensitive as manometry in the detection of oesophageal motility disorders.

Adult↗

Clinical spectrum of "solitary ulcer" of the rectum.

A review of 40 patients with "solitary ulcer" of the rectum confirmed by rectal biopsy has provided information about the natural history of this unusual condition. At presentation, symptoms usually were the passage of blood and mucus per rectum, alteration in bowel habits, and anorectal pain. Solitary or multiple ulcers were found within 13 cm of the anal margin in 27 patients and were usually sited anteriorly; in 13 patients macroscopic ulceration was absent, though the histopathology of the rectal biopsy specimens was otherwise similar. Rectal mucosal prolapse was found in 25 of 29 patients examined specifically for this. Thirty-one patients were followed-up for a mean period of 4.8 yr (range 1-15 yr). In 22 patients, rectal ulceration was observed at presentation. In 14 of these patients, ulceration persisted despite treatment. In 9 patients presenting without macroscopic ulceration, rectal ulcers were not observed during follow-up; thus two patient groups were apparent. Neither medical nor local surgical treatment consistently achieved relief of symptoms or healing of the lesion.

Adolescent↗

Gastric emptying of solids in man.

The influence of the type and size of solid particles on their emptying from the stomach was studied using isotopically labelled chicken liver and inert particles in normal subjects and in patients who had undergone gastric surgery. In normal subjects, initial emptying of the liver was slower than that of inert particles both for large liver cubes (1 cm) and small cubes (0.3 cm). Liver emptying subsequently accelerated to be faster than emptying of the inert particles. Overall emptying of the liver given as small cubes was faster than large cubes; 50% emptied in 50 minutes and 70 minutes respectively. In the postoperative subjects, emptying of the liver and of the inert particles was identical. The findings are consistent with the hypothesis that solid foods such as liver are ground down and 'liquified' by the action of gastric peristalsis before being discharged to the duodenum. Ingested particle size appears to influence the rapidity of this process, which should be distinguished from the propulsive function of the stomach where small solid particles are concerned.

Adult↗

An evaluation of 99mTc pertechnetate scanning for the detection of coeliac disease and Crohn's disease.

To investigate the use of abdominal scintiscanning in the detection of small bowel pathology, the accumulation of pertechnetate (99mTc), following intravenous injection, has been studied in 21 patients with coeliac disease, 13 patients with Crohn's disease and in 83 control subjects without known small bowel disease. Although a trend for a greater accumulation of 99m Tc was noted in patients with coeliac disease and Crohn's disease compared with controls (P less than 0.025) there was a large overlap in individual studies. Under the conditions of this study the accumulation of 99mTc by the small bowel did not provide a reliable diagnostic test for coeliac disease or Crohn's disease of the small intestine. The accumulation of 99mTc pertechnetate by normal small bowel suggests that scintiscanning with this radiopharmaceutical does not provide a consistently reliable method for the detection of small bowel pathology.

Adult↗

Acetaminophen absorption and metabolism in celiac disease and Crohn's disease.

To investigate further the conflicting results in reports of drug absorption in patients with small intestinal mucosal disease, gastric emptying and the disposition of acetaminophen were assessed simultaneously in 41 subjects (13 controls, 12 patients with Crohn's disease, and 16 with celiac disease). Acetaminophen absorption as judged by plasma concentrations and gastric emptying were slower in patients with celiac disease and Crohn's disease. Total drug absorption as indicated by urinary recovery did not differ, but plasma acetaminophen half-life was shorter and glucuronide conjugation was enhanced in the patients with Crohn's disease. Contrary to expectation, the mean rate constant for acetaminophen absorption from the small intestine was not decreased in Crohn's disease and celiac disease. The abnormally slow acetaminophen absorption in the patients with Crohn's or celiac disease could be explained by slower gastric emptying of the drug solution.

Acetaminophen↗

Effect of nifedipine on oesophageal motility and gastric emptying.

Manometric studies have been performed to determine the effect of nifedipine on lower oesophageal sphincter (LOS) pressure and distal oesophageal motility in healthy subjects, in patients with diffuse oesophageal spasm, and in a patient with achalasia. Significant reductions in LOS pressure and in the amplitude of peristaltic oesophageal contractions were observed. In the patients with diffuse oesophageal spasm the amplitude and frequency of non-peristaltic (spasm) contractions were also reduced. Nifedipine did not significantly influence gastric emptying rates of solid and liquid components of a test meal in normal subjects nor in patients who had undergone gastric surgery.

Adolescent↗

Abnormal gastric emptying in primary anorexia nervosa.

The gastric emptying rate was measured in 10 female patients with primary anorexia nervosa and 12 healthy volunteers, using a scinti-scanning technique for the simultaneous study of the liquid and solid components of a test meal. The emptying rate of both the liquid and the solid phase components of the meal was significantly slower in patients with anorexia nervosa. The aetiological and therapeutic implications of this finding are discussed.

Adolescent↗

Benign gastric ulceration in pernicious anemia.

Benign gastric ulceration occurred in a patient with pernicious anemia in association with aspirin therapy. Previous reports of benign gastric ulceration in patients with achlorhydria are reviewed, and the potential role of aspirin in the pathogenesis of benign ulceration in the absence of acid is discussed.

Achlorhydria↗

The effect of posture on errors in gastric emptying measurements.

Scintigraphic gastric emptying measurements were made with subjects supine and upright using a dual-detector rectilinear scanner. Previously reported variations of the depth of activity during the course of a study were again found with both postures. Although there was no significant mean depth change in the group when upright, some individual variations were substantial. Measurements with a gamma camera demonstrated similar changes of depth of stomach contents with seated subjects. The resulting variations of attenuation of the emergent radiation lead to appreciable errors in the emptying rates determined by unilateral detection. In about half the cases the mean movement of a 99Tcm-labelled solid phase marker exceeded 1 cm; such a movement led to an average 20% error in emptying rate determination by an anterior detector. Depth changes of a liquid marker were less marked, exceeding 0.5 cm in half the subjects; this movement gave rise to an average 6% error when 113Inm was used as the tracer.

Diagnostic Errors↗

Sedation for upper gastro-intestinal endoscopy. A comparison of oral temazepam and i.v. diazepam.

Temazepam 20 mg orally was compared with titrated doses of i.v. diazepam as sedation for elective upper gastro-intestinal endoscopy. The mean time from taking oral temazepam to endoscopy was 66 min, and from i.v. diazepam to endoscopy was 10 min. The endoscopists found that the sedation achieved was the same in both groups and allowed adequate examination of the upper alimentary tract. The oral presentation, avoiding the pain of injection and the possible shorter duration of action, made oral temazepam preferable to i.v. diazepam.

Administration, Oral↗

Alcohol absorption, gastric emptying and a breathalyser.

1 The value of a portable breathlyser (Alcometer AE-M2) in the assessment of gastric emptying after alcohol ingestion was investigated by comparing breath and venous blood alcohol concentrations with simultaneous scintigraphic measurements of gastric emptying rate. 2 Alcohol absorption, as determined by the area under the venous blood alcohol concentration-time curve during the first 30 min, correlated with gastric emptying during the same period, implying dependence of the rate of alcohol absorption on gastric emptying rate. 3 There was no correlation between breath and venous alcohol concentrations during the first 15 min after alcohol ingestion, but a significant correlation was observed thereafter. 4 Breath alcohol measurements may be sufficient to detect gross alterations in gastric emptying but measurements of venous blood alcohol are likely to be more reliable.

Breath Tests↗