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Biomedical subjects

R C Heading

Publications and source records attributed to R C Heading.

At least 109 records · Page 6Linked to original sources
PubMed1980

Dynamic imaging of the stomach by real-time ultrasound--a method for the study of gastric motility.

The use of real-time ultrasonic imaging of the stomach for the study of gastric contractions in response to a liquid test meal is described. Gastric contractions in the pyloric antrum and distal body of the stomach were observed on closed circuit television, recorded on to cassette tape and also imaged on polaroid and ciné film. Gastric contractions were recorded from the pyloric antrum by longitudinal scanning in the lower epigastrium and reproducible motility tracings were obtained on a fibreoptic chart recorded. Intravenous metoclopramide enhanced the magnitude and frequency of antral movement, which was abolished by intravenous propantheline. Real-time ultrasonic imaging permits the non-invasive study of gastric contractions. It is safe, may be repeated as required, and provides a method for the study of the effect of drugs and disease states on gastric motility.

Food↗
PubMed1980

Gastric motility.

Explore the source record for details and available documents.

Action Potentials↗
PubMed1980

Gastric emptying in diabetic autonomic neuropathy.

Gastric emptying was studied in 12 diabetic patients, six with and six without objective evidence of autonomic neuropathy and in 20 nondiabetic controls, using a double isotope scintiscanning technique which differentiated between solid and liquid emptying. Three patients with autonomic neuropathy exhibited gastric stasis, although this was detected by conventional radiology in only one. Neither the patients with stasis nor those without exhibited abnormally rapid early gastric emptying. In patients without stasis, the normal differentiation between solid and liquid emptying was impaired, suggesting an abnormality of antral peristalsis not attributable to vagal denervation. Both intravenous and oral metoclopramide produced symptomatic improvement in two patients with gastric stasis and restored their gastric emptying to normal.

Adult↗
PubMed1979

Effect of gel fibre on gastric emptying and absorption of glucose and paracetamol.

To determine the part played by altered gastric emptying in the modification of glucose absorption by gel fibres, glucose tolerance tests were done in seven healthy volunteers with and without the addition of pectin to the ingested glucose solution and after pharmacological inhibition of gastric emptying with propantheline. Compared with the controls, pectin significantly reduced blood-glucose. Propantheline had a similar but more pronounced effect. Pectin and guar gum did not substantially alter glucose tolerance in a patient who had had total gastrectomy. In a further investigation, gastric emptying and paracetamol absorption were studied simultaneously in fourteen subjects. In eight of these the study was repeated after addition of guar gum and pectin to the ingested paracetamol. Both gastric emptying and paracetamol absorption were slower after gel fibre but the total absorption of the drug, reflected in urinary recovery, was not significantly reduced. The results suggest that the effects of guar gum and pectin on glucose tolerance and paracetamol absorption could be due simply to alteration in the rate of gastric emptying.

Absorption↗
PubMed1979

Effects of 'elemental' diets on absorptive and enzymic activities and on 5-fluorouracil toxicity in rat small intestine.

1. Water absorption and cytoplasmic dipeptidase activities were determined in isolated rat small intestine after animals had fed on various 'elemental' diets or a standard rat diet and after a single injection of 5-fluorouracil. 2. Vivonex diets were associated with a decrease in dry weight of the small intestine and an increase in glucose and water absorption in vitro. 3. The nature of the dietary nitrogen profoundly affects the activities of intestinal peptidases. 4. Water absorption was severly depressed 3 days after 5-fluorouracil administration: the extent of depression was independent of the diet. Thus, any ameliorative effects of 'elemental' diets on 5-fluorouracil toxicity are unlikely to be mediated by direct protection of intestinal absorption.

Animals↗
PubMed1979

Effect of long-term cimetidine on gastric acid secretion, serum gastrin, and gastric emptying.

Gastric acid secretion, gastric emptying, fasting serum gastrin and the serum gastrin response to a meal were measured in duodenal ulcer patients before, and at least five days after completing prolonged treatment with cimetidine (1 or 2 g/day for four or eight weeks followed by 600 mg twice daily for six months). Fasting serum gastrin and the gastrin response were also measured during treatment. Compared with pretreatment values, fasting serum gastrin concentrations were raised both during and five to 31 days after stopping treatment (P less than or equal to 0.02). The integrated gastrin response and the rate of gastric emptying of the solid component of the meal were increased during treatment (P less than 0.001 and P less than 0.002 respectively) but returned to pretreatment levels after stopping therapy. No significant changes were observed in the basal or maximal acid outputs or the rate of emptying of the liquid component of the meal. The results imply that the hypergastrinaemia associated with long-term cimetidine therapy does not result in increased gastric acid secretion.

Cimetidine↗
PubMed1979

High flow oxygen therapy for pneumatosis coli.

Symptomatic and radiological resolution of pneumatosis coli was achieved by intermittent high flow oxygen therapy in five patients. In each case the extent of the disease was defined by colonoscopy and contrast radiography before treatment. Despite the confirmation of pneumocyst resolution, recurrence of colonic gas cysts was noted in two patients at six months and one year after treatment. Bacteriological studies indicated that resolution of the disease, induced by oxygen therapy, was not associated with eradication of anerobic bacteria from stool and colonic mucosa. The clinical features and response to treatment of this group of patients are discussed, with particular reference to previously reported methods of oxygen administration.

Aged↗
PubMed1979

A single scan technique for estimating acid output.

A single scan technique using 99mTc has been developed for the measurement of gastric acid output. After an overnight fast, pentagastrin (6 microgram/kg S.C.) was given 15 min before 99mTc (1 mCi i.v.), and a scan of the abdomen was performed 15 min later using a double-headed scanner. Accumulation of isotope within the stomach was then calculated from the scan and expressed as a percentage of the injected dose. Pentagastrin-stimulated intragastric activity correlated with acid output measured conventionally on a separate occasion (r = 0.87, P less than 0.0001). The test is rapidly performed with minimal inconvenience and discomfort to the patient, and the dose of irradiation used is small. The advantages of the method compared with intubation and gastric aspiration are discussed.

Gastric Acidity Determination↗
PubMed1978

Kinetics of acetaminophen absorption and gastric emptying in man.

Eight healthy male volunteers ingested an aqueous solution containing acetaminophen (20 mg/kg) and a nonabsorbable isotopic marker. The concentrations of unconjugated acetaminophen in samples of blood plasma taken at frequent intervals were measured by gas-liquid chromatography. The data points followed a smooth curve in most cases and were fitted to the classical two-compartment pharmacokinetic model to obtain KA, the apparent first-order rate constant for absorption from the gastrointestinal tract. Gastric emptying was measured simultaneously from serial scintiscans of the subject's abdomen. The subjects were also studied after intramuscular injection of meperidine (150 mg) and pentazocine (60 mg) with and without naloxone (1.2 mg). The acetaminophen absorption curves and gastric emptying patterns were consistent with negligible absorption from the stomach. A new model is proposed in which the conventional single compartment used to represent the gastrointestinal tract is replaced by two compartments: one represents the stomach and the other the small intestine, from which absorption occurs rapidly. Pharmacokinetic analysis using this model showed good agreement in all cases, and provided an estimate of KA, the first-order rate constant for drug transfer from the intestinal lumen into the systemic circulation. The mean half-time for transfer was 6.8 +/- 0.9 min. As expected, KA was greater than KG (the first-order rate constant for gastric emptying), showing that gastric emptying was rate-limiting in the absorption of acetaminophen. The value of KA was greater than KA and the two were not related. The value of KA was not equal to KG in most studies because gastric emptying was not a single exponential process.

Acetaminophen↗
PubMed1978

Changes in absorptive and peptide hydrolase activities in rat small intestine after administration of 5-fluorouracil.

1. Glucose absorption, water absorption and dipeptide hydrolase activities have been determined in isolated rat small intestine at 1, 3, 5 and 21 days after a single intraperitoneal injection of 5-fluorouracil. 2. Absorption rates and enzyme activities were elevated 1 day after treatment, but were reduced to 40% of control values at 3 and 5 days. Changes were seen regardless of whether absorption was expressed per unit length or per unit dry weight of intestine. 3. There were highly significant positive correlations between glucose or water absorption rates and peptidase activities, especially in proximal jejunum. The most significant correlation was observed between water absorption rate and jejunal L-Leu-Gly hydrolase activity. 4. Malabsorption may account for some of the gastrointestinal side effects associated with treatment with 5-fluorouracil. Enzyme measurements may be useful as an index of intestinal function.

Animals↗
PubMed1978

Premedication for upper gastrointestinal endoscopy: a comparative study of flunitrazepam, diazepam and neuroleptanalgesia.

Flunitrazepam or diazepam with atropine and a combination of phenoperidine, droperidol and cyclizine (neuroleptanalgesia) were compared as premedication in three groups of 25 patients undergoing routine upper gastrointestinal endoscopy. Drug doses were titrated carefully against response and all three regimes were found to be similar in terms of safety, patient co-operation, relaxation and speed of recovery. Neuroleptanalgesia however produced a statistically significant rise in endtidal pCO2 and systolic blood pressure. The benzodiazepines, and in particular flunitrazepam, produced a significantly greater amnesia for the procedure, patients given these drugs being more willing to undergo repeat endoscopy.

Anti-Anxiety Agents↗
PubMed1978

Lower oesophageal sphincter response to gastrin--pharmacological or physiological?

The response of the lower oesophageal sphincter (LOS) to intragastric instillation of protein was assessed in 10 healthy volunteers. Sphincter pressures were measured by a rapid pull-through technique and serum gastrin concentrations during each test were determined by radioimmunoassay. Despite stimulation of gastrin release by protein instillation, no significant change in LOS pressure was observed. However, intravenous pentagastrin (0.25 and 0.5 microgram/kg) produced an immediate increase in sphincter pressure, which then returned to the basal level within four minutes. Thus, although pentagastrin is an effective pharmacological stimulant of the sphincter, endogenous gastrin appears not to be a physiological determinant of LOS pressure in man.

Adult↗
PubMed1978

Obsolete but dangerous antacid preparations.

One case of acute hypercalcaemia and two of recurrent nephrolithiasis are reported in patients who had regularly consumed large amounts of calcium carbon-ate-sodium bicarbonate powders for more than 20 years. The powders had been obtained from pharmacists unknown to the patients' medical practitioners. It is suggested that these preparations were responsible for the patient's problems, and that such powders should no longer be freely obtainable.

Aged↗
PubMed1978

Spontaneous mid-oesophageal rupture.

The clinical presentation and management of spontaneous rupture of the middle third of the oesophagus is described in two patients. Early presentation and treatment in one case led to uncomplicated recovery. In the other patient late presentation and diagnosis resulted in delayed surgical intervention with an unsuccessful outcome. The nature of this rare lesion is discussed and nine previously described cases are reviewed.

Adult↗
PubMed1978

Effect of cimetidine on serum gastrin and gastric emptying in man.

Paired studies of gastric emptying were performed in 10 healthy volunteers using a scintiscanning technique which provides information about the rate of emptying of both the liquid and solid components of a standard meal. Emptying rates of both components were not significantly different after oral administration of 400 mg cimetidine than after placebo. The increase in serum gastrin concentration produced by the meal was significantly greater after cimetidine than after placebo but there was no relationship between individual cimetidine-placebo differences in gastrin response and the corresponding cimetidine-placebo differences in rates of emptying. A positive correlation was demonstrated between the gastric emptying rate of the liquid component and the 1 h cimetidine absorption, indicating that normal individual variation in gastric emptying is probably responsible for much of the normal individual variation in the rate of cimetidine absorption.

Adult↗