No abstract

A series of 34 histologically verified cases of pancreatic heterotopia in the records of the Department of Pathology at the University of Edinburgh between 1959 and 1979 has been analysed in order to determine the clinical significance of this unusual condition. In 13 patients (38 per cent) the heterotopic pancreatic tissue was symptomatic (i.e. the symptoms regressed completely on its removal). A correlation has been established between the presence of symptoms, the size of the lesion and the extent of mucosal involvement. Clinically significant lesions are greater than 1.5 cm in maximum diameter and are adjacent to or directly involve the mucosa.

Gastric emptying is a significant determinant of the blood glucose response after an oral carbohydrate load [1] due to the key role this process plays in regulating the rate of nutrient delivery to the small intestine. Gastric emptying may therefore be a previously under-recognized contributor to variations in glycaemic control in diabetes mellitus. Faster rates of gastric emptying have been reported not only in rat models of insulin-dependent diabetes mellitus (IDDM) [2,3] but also in patients with IDDM [4,5] and recent studies suggest that modulation of gastric emptying could be used to improve glycaemic control in patients with diabetes [6].Amylin is a 37 amino acid polypeptide co-secreted with insulin by pancreatic beta cells, in response to nutrient stimuli. It circulates at concentrations of 5±30 pmol/l in normal subjects. IDDM patients are not only insulin deficient but also amylin deficient [7,8]. Amylin concentrations in IDDM patients range from the lower end of the normal range to undetectable and do not increase in response to a glucose load. The peptide pramlintide is a stable trisub- Diabetologia (1998) Summary In a previous study we have shown that an intravenous infusion of pramlintide (an analogue of human amylin) delayed gastric emptying, but the dose of pramlintide was supraphysiological in relation to the amylin response to food in non-diabetic subjects. The purpose of this study was to examine the dose response relationship of subcutaneous injections of pramlintide on gastric emptying and to determine whether administration of the drug before one meal has an impact on the subsequent meal. Eleven men with insulin-dependent diabetes mellitus were studied in a double-blind, randomised, four-way crossover design. None had autonomic neuropathy. Euglycaemia was maintained overnight before the study day. At 30 min the patients self-injected their usual morning insulin and at 15 min they injected the study drug (either placebo or 30, 60 or 90 mg pramlintide) subcutaneously. At 0 min they ate a standard meal consisting of a pancake, labelled with 99m Tc, and a milkshake containing 3-ortho-methylglucose (3-OMG). Gastric emptying images were obtained for the next 8 h. At 240 min the subjects ate a similar meal, but on this occasion the pancake was labelled with 111 In. All three doses of pramlintide delayed emptying of the solid component of the first meal (p < 0.004) with no significant difference between the drug doses. There were no differences between placebo and pramlintide after the second meal. All three doses of pramlintide resulted in a prolongation in the time to peak plasma 3-OMG level (p < 0.0001) after the first meal but there was no difference after the second meal. [Diabetologia (1998) 41: 577±583]

Pramlintide, a human amylin analogue, reduces hyperglycaemia after meals in patients with insulin-dependent diabetes mellitus (IDDM). We investigated whether this was due to delayed gastric emptying. Eight men with uncomplicated IDDM were studied twice in a randomised, double-blind crossover design. Euglycaemia was maintained overnight by intravenous infusion of glucose and/or insulin and the following morning a 5-h infusion of pramlintide 25 micrograms/h or placebo was started at 08.00 hours. At 08.30 hours the patients injected their normal morning insulin dose subcutaneously and 30 min later ate a meal (600 kcal, 50% carbohydrate) of which the solid component was labelled with Technetium-99 m and the liquid with Indium-111 to quantify gastric emptying. Gamma-scintigraphic images were obtained every 20 min for the next 4 h. Insulin and glucose were infused as necessary to maintain blood glucose levels within 3 mmol/l of the pre-meal value. Compared to placebo, pramlintide significantly delayed emptying of both liquid (median lag time 69 vs 7.5 min) and solid (median lag time 150 vs 44.5 min) components of the meal. Pramlintide delayed gastric emptying so much that t50 values could not be calculated for solid or liquid. Amylin agonists such as pramlintide may, therefore, be of value in improving glycaemic control in IDDM by modifying gastric emptying.

SUMMARY To study the relationships between gastric antral and proximal duodenal motor activity, and the movement of liquid across the pylorus, 10 Currently available methods for the study of gastric emptying in man do not provide information about the movements of gastric contents in relation to individual gastric peristaltic contractions. Manometric methods permit observation of the timing and magnitude of pressure changes within the gastric lumen'l and some electrical recordings from the human stomach and duodenum have been obtained2 5 6 but although both of these give information about muscle contraction, they do not identify the movement of intragastric contents. Simultaneous studies of antral contractions and gastric emptying in man have been undertaken using intubation methods,5 7 and also with a scintigraphic procedure,8 9 but much of the current knowledge about the relationships between flow of luminal contents and contractions of the human stomach, pylorus, and duodenum has been obtained from radiological investigations using contrast media.3 10