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Biomedical subjects

P E Harding

Publications and source records attributed to P E Harding.

12 recordsLinked to original sources

Relationships between oesophageal transit and solid and liquid gastric emptying in diabetes mellitus.

In 87 randomly selected diabetic patients (67 type 1, 20 type 2) and 25 control subjects, gastric emptying of digestible solid and liquid meals and oesophageal transit of a solid bolus were measured with scintigraphic techniques. Gastrointestinal symptoms, autonomic nerve function and glycaemic control were evaluated in the diabetic patients. Gastric emptying and oesophageal transit were slower (P less than 0.001) in the diabetic patients compared with the control subjects, and each was delayed in about 40% of them. There was a relatively weak (r = 0.32; P less than 0.01) relationship between solid and liquid gastric emptying, and no significant correlation (r = 0.11, NS) between oesophageal transit and gastric emptying of the solid meal. Scores for upper gastrointestinal symptoms and autonomic nerve function correlated weakly (r = 0.21; P less than 0.05) with both oesophageal transit and gastric emptying. Gastric emptying of the liquid meal was slower (P less than 0.05) in patients with blood glucose concentrations greater than 15 mmol/l. These results indicate that gastric emptying in patients with diabetes mellitus should be assessed by liquid as well as by solid test meals and that oesophageal transit should not be used as a predictor of generalised diabetic gastroenteropathy.

Diabetes Mellitus

Hyperglycaemia slows gastric emptying in type 1 (insulin-dependent) diabetes mellitus.

In 10 patients with Type 1 (insulin-dependent) diabetes mellitus gastric emptying of a digestible solid and liquid meal was measured during euglycaemia (blood glucose concentration 4-8 mmol/l) and during hyperglycaemia (blood glucose concentration 16-20 mmol/l). Gastric emptying was studied with a scintigraphic technique and blood glucose concentrations were stabilised using a modified glucose clamp. Patients were also evaluated for gastrointestinal symptoms, autonomic nerve function and glycaemic control. When compared to euglycaemia, the duration of the lag phase before any of the solid meal emptied from the stomach (p = 0.032), the percentage of the solid meal remaining in the stomach at 100 min (p = 0.032) and the 50% emptying time for the solid meal (p = 0.032) increased during hyperglycaemia. The 50% emptying time for the liquid meal (p = 0.042) was also prolonged during the period of hyperglycaemia. These results demonstrate that the rate of gastric emptying in Type 1 diabetes is affected by the blood glucose concentration.

Adult

Prolactin suppression in the treatment of premenstrual syndrome.

Abnormal secretion of prolactin is amongst the many disorders of hormone secretion which have been proposed as potential causes for the common syndrome of premenstrual tension. Eight women suffering from this disorder participated in a five-month double-blind crossover trial of bromocriptine (5 mg per day) given in the luteal phase of the cycle. Significant improvement in most symptoms occurred during active as opposed to placebo therapy, together with objective evidence of a decrease in premenstrual weight gain and breast enlargement. This corresponds with the results of other studies which used bromocriptine in this dosage. The effect may be mediated by suppression of prolactin secretion, but could equally be a direct effect of bromocriptine.

Adult

DDAVP in the treatment of diabetes insipidus: a clinical study.

In three cases of established cranial diabetes insipidus, the effectiveness of the new vasopressin analogue 1-desamino-8-D-arginine vasopressin (DDAVP) in controlling diabetes insipidus is demonstrated. A single dose of 20 micrograms of DDAVP given intranasally had an antidiuretic action from 16 to 24 hours in the three cases, and 10 micrograms given twice daily intranasally was effective in controlling the diabetes insipidus with no side effects. All the patients preferred this form of therapy to their previous treatment.

Adult

A case of myxoedema coma successfully treated by low dose oral triiodothyronine.

Myxoedema coma is fortunately rare and is probably rarer in a warm climate such as Australia. It carries a high mortality rate. Its correct management is still a controversial issue. A case of severe myxoedema coma who was successfully treated is described. Thyroid hormone was replaced in the form of triiodothyronine given orally in doses of 20-40 microng/day. There was an improvement in body temperature within six hours of the first dose; this was accompanied by a brisk fall in serum CPK and cholesterol with a rapid rise of plasma T3 into the euthyroid range. There was a defect in water excretion which was rapidly reversed as renal function returned to normal. Review of the literature suggests that low dose oral therapy with T3 is a satisfactory form of initial management.

Aged

Phenformin and lactic acidosis.

Thirty-eight patients who presented with diabetes and a changed state of consciousness satisfied the criteria for lactic acidosis. Sixteen patients were non-ketotic, and 15 of these were receiving phenformin on admission. In all but one of these 15 patients, however, additional renal or cardiovascular abnormalities, or both, could be identified, which supported a multifactorial aetiology for lactic acidosis. Advanced age and cardiovascular and renal disease are absolute contraindications to the use of phenformin in diabetics.

Adolescent

Intentional radioiodine ablation in Graves' disease.

In a series of 50 cases of Graves' disease qualifying for therapy with radioiodine, "ablative" doses of radioiodine resulted in hypothyroidism in 92% of cases at six months. Hypothyroidism was treated by thyroxine or tri-iodothyronine replacement therapy. Rapid responses and predictable outcome were regarded as important advantages. Intentional ablation is particularly convenient in situations where clinical and biochemical follow-up may be difficult. Further follow-up studies are needed to determine whether ablative therapy is the treatment of choice in all cases of Graves' disease.

Administration, Oral

Effect of infusion of insulin into portal vein on hepatic extraction of insulin in anesthetized dogs.

Hepatic extraction of insulin was examined in anesthetized dogs before and after constant infusion of insulin (20 and 50 mU/min) with use of samples from the portal vein, mesenteric vein, left common hepatic vein, and the femoral artery. In 19 dogs, measurement of portal vein insulin concentration indicated an overall recovery of 110% of the insulin infused. The range varied from 9 to 303%, indicating the potential for serious error in sampling the portal vein. Equilibrium arterial insulin concentrations were achieved 20 min after starting the infusion. Prior to insulin infusion, hepatic extraction of insulin averaged 4.56 plus or minus 0.43 mUmin, representing an extraction coefficient of 0.42 of the insulin presented to the liver. The proportion of insulin extracted by the liver did not change significantly during insulin infusion despite a 10-fold increase in portal vein insulin concentrations. During the infusion of insulin, a significant proportion of the extraheptic clearance of insulin occurred in the mesenteric circulation. Infusion of insulin was associated with a significant increase in insulin extraction by tissues other than the liver and splanchnic beds. Initially, hepatic glucose output average 36 plus or minus 3 mg/min; by 20 min after insulin infusion, it was 16 plus or minus 5 mg/min. Despite continuation of insulin infusion, hepatic glucose output returned to control values even though arterial glucose concentration continued to fall. Hepatic glucose output increased with termination of insulin infusion.

Animals

Persistent pancreatic glucagon but not insulin response to arginine in pancreatectomized dogs.

Effects of total pancreatectomy on plasma glucagon, insulin and glucose responses to arginine were determined in 5 dogs. Portal vein and femoral artery samples were obtained in response to an arginine infusion (10 g/30 min) prior to, 1 h, 1 day and 1 week after pancreatectomy. Glucagon was measured using pancreatic-specific antiserum 30K (Unger, Dallas). Before pancreatectomy arginine significantly increased portal vein glucagon from 373 plus or minus 36 to 595 plus or minus 31 pg/ml and femoral artery levels from 233 plus or minus 28 to 342 plus or minus 74 pg/ml. Portal vein and femoral artery insulin concentrations of 74 plus or minus 21 and 17 plus or minus 3 muU/ml increased significantly to 173 plus or minus 64 and 31 plus or minus 7 muU/ml. Glucose levels did not change. One h after pancreatectomy, portal vein glucagon decreased to 121 plus or minus 15 pg/ml but increased to 230 plus or minus 42 pg/ml after arginine. Elevated blood glucose and the necessity for insulin treatment established the adequacy of pancreatectomy. Furthermore portal vein insulin levels were undetectable and unresponsive to arginine or a combination of glucose, glucagon, and tolbutamide 1 week after pancreatectomy. One day after pancreatectomy arginine significantly increased portal vein glucagon from 343 plus or minus 42 to 776 plus or minus 152 pg/ml. One week after pancreatectomy basal glucagon values were 374 plus or minus 30 in the portal vein and 360 plus or minus 49 in the femoral artery and responded to 1226 plus or minus 641 and 825 plus or minus 270 pg/ml, respectively, with arginine. Chromatography of plasma from one pancreatectomized dog on Sephadex G-50 after arginine stimulation revealed that much of the material cross-reacting with antibody 30K was eluted from the column earlier than either 125I-insulin or 125I-glucagon. In contrast, peak glucagon activity in plasma obtained from a normal human given arginine eluted from the column between the peak of 125I-insulin and 125I-glucagon; glucagon added to human plasma also was recovered in this same area between the 125I-insulin and 125I-glucagon peaks. These results suggest that some of the material that reacted with 30K antibody and which increased after pancreatectomy in response to arginine has a molecular weight greater than pancreatic glucagon. At autopsy no pancreatic tissue could be identified. Thus, after pancreatectomy, validated by absent insulin responses, the glucagon response to arginine was normal or increased. Since arginine is not thought to increase intestinal glucagon-like immunoreactive material, the source and nature of the material measured as glucagon after pancreatectomy is unknown, but may be important to any understanding of plasma glucagon measurements.

Animals