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Biomedical subjects

M R Lucey

Publications and source records attributed to M R Lucey.

83 records · Page 5Linked to original sources

Primary biliary cirrhosis in men.

To determine whether primary biliary cirrhosis differed in men and women we reviewed the presenting features and clinical course of 39 men and 191 women with primary biliary cirrhosis followed at this unit between 1970 and 1984. Age and severity of disease at time of diagnosis were similar in both groups. Pruritus was significantly less common in men than in women both at diagnosis and throughout the period of follow up (p less than 0.01). The difference in incidence of pruritus at diagnosis was most evident when the male group were compared with a group of premenopausal women, an observation which is consistent with involvement of sex steroid metabolism in the origin of pruritus. Skin pigmentation was also less marked in men at diagnosis (p less than 0.05). Autoimmune associated conditions, especially sicca syndrome, were more common in women. Survival was similar among men and women although hepatoma developed significantly more frequently in male patients (p less than 0.01).

Female↗

Autonomic regulation of postprandial plasma somatostatin, gastrin, and insulin.

To evaluate the neural regulation of postprandial somatostatin release we studied the effect of blockade of (a) alpha-adrenergic and beta-adrenergic and (b) cholinergic receptors on the plasma somatostatin, gastrin and insulin responses to a standard meal in two groups of five fasting healthy male volunteers. Thymoxamine (0.1 mg/kg iv over two minutes then 10 mg/hour for two hours) and propranolol (0.15 mg/kg iv over two minutes, then 0.75 mg/kg/hour for two hours) were started just before eating while atropine (0.04 mg/kg/im) was given at 15 minutes on completion of the meal. There was a prompt and sustained rise in plasma somatostatin after a control meal in all experiments. This rise was arrested by atropine but not altered by either thymoxamine or propranolol. The plasma gastrin response to a meal was moderately enhanced by thymoxamine and markedly enhanced by atropine. Postprandial insulin release was not affected by alpha- or beta-adrenergic blockade but was abolished by atropine. The effect of atropine on the postprandial plasma somatostatin rise might have been mediated through reduction in gastric acidity or delay in gastric emptying. Hence we gave five fasting male volunteers and intraduodenal infusion of fat emulsion (25 calories in 30 minutes) on two occasions both alone and after atropine. Plasma somatostatin rose during the fat infusion alone and this rise was abolished by atropine. These data suggest that (a) cholinergic but not adrenergic mechanisms are important modulators of plasma somatostatin release after orally ingested and intraduodenally infused nutrients (b) atropine abolishes plasma somatostatin release independently of its effects on gastric acidity and motility and (c) are consistent with the hypothesis that atropine potentiates postprandial gastrin release through reduction of somatostatin mediated inhibition.

Adult↗

Response of circulating somatostatin, insulin, gastrin and GIP, to intraduodenal infusion of nutrients in normal man.

We have studied the effect of direct infusion of nutrients into the duodenum of normal subjects on circulating plasma somatostatin, insulin, gastrin and gastric inhibitory polypeptide (GIP) levels. Six normal subjects were given on four separate occasions 150 ml of isotonic solutions containing 100 calories of carbohydrate, protein, or fat, and a control solution of saline, by infusion into the second part of the duodenum. Plasma somatostatin rose slightly after carbohydrate, mean basal 30 +/- 3 pg/ml, peak 46 +/- 16 pg/ml at 15 min; and more markedly after protein, peak 57 +/- 9 pg/ml at 30 min. However, fat was the most potent intraduodenal stimulus to plasma somatostatin release into circulation, peak 101 +/- 11 pg/ml at 30 min. The plasma insulin rise was greatest after carbohydrate, peak 68 +/- 10 i.u., but there was a significant rise after protein also, peak 34 +/- 6 i.u. Plasma gastrin rose significantly after protein only, peak 70 +/- 22 pg/ml. Plasma GIP rose markedly after carbohydrate, basal 506 +/- 50 pg/ml, peak 1480 +/- 120 pg/ml. Protein was also a potent stimulus of circulating plasma GIP release, peak 1200 +/- 190 pg/ml, while fat was the least potent, peak 730 +/- 190 pg/ml. Thus, calorie for calorie, fat is the most potent intraduodenal nutrient stimulus of circulating somatostatin. We postulate therefore that somatostatin may be an enterogastrone--a circulating hormone released by intraduodenal fat which inhibits gastric acid secretion. Fat is the least potent intraduodenal nutrient stimulus of circulating GIP release. This is evidence against the hypothesis that circulating GIP acts as an enterogastrone.

Adult↗

Does gastric acid release plasma somatostatin in man?

Food and insulin hypoglycaemia raise plasma concentrations of somatostatin. Both also stimulate gastric acid secretion but it is not clear whether gastric acid itself has any effect on somatostatin secretion. We, therefore, studied the effect on plasma concentrations of somatostatin of infusion of 0.1 N HC1 into the stomach and duodenum of healthy subjects. Plasma somatostatin did not rise with a small dose of HC1 given intragastrically (15 mmol) or intraduodenally (4 mmol). After an intraduodenal infusion of 60 mmol HC1 over 30 minutes, sufficient to reduce intraluminal pH to 2, plasma somatostatin rose moderately in five subjects from a mean value (+/- SEM) of 32 +/- 3 pg/ml to a peak at 10 minutes of 54 +/- 11 pg/ml. It is concluded that: (a) intragastric acid infusions do not release circulating somatostatin in man; and (b) that intraduodenal acidification albeit at grossly supraphysiological doses is a moderate stimulus of plasma somatostatin release. Therefore, gastric acid is unlikely to be a major factor mediating postprandial plasma somatostatin release in man.

Adult↗

Alcoholism treatment after liver transplantation: lessons learned from a clinical trial that failed.

Alcoholic liver disease is the second most common indication for liver transplantation in the United States. The lack of alcoholism treatment studies led us to study motivational enhancement therapy (MET) plus naltrexone after transplant. The authors could not complete this study. Sixty alcoholic patients were to receive MET plus naltrexone or placebo for 6 months. Fifty men and 5 women were screened. Nine died and 15 were not approached. Of 31 approached, 20 were ineligible, 11 refused, and 5 entered but dropped out before completion. Barriers to posttransplant alcoholism included infirmity, intensive medical management, and denial for alcoholism treatment. Because 30%-50% of alcoholic patients drink after transplant, the authors suggest using MET alone pretransplant.

Adaptation, Psychological↗