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Biomedical subjects

S R Bloom

Publications and source records attributed to S R Bloom.

At least 1,099 records · Page 61Linked to original sources
PubMed1980

A radioimmunoassay of gastric inhibitory polypeptide in human plasma.

A sensitive radioimmunoassay for the measurement of human gastric inhibitory polypeptide (GIP), using pure porcine GIP, has been developed. Cross-reactivity of the antiserum with all available mammalian gut peptide preparations was negligible with the exception of glucagon when it was approximately 1%. Two major molecular forms of GIP were detectable in plasma and tissue extracts, one of large molecular size and the other corresponding to the elution coefficient of pure porcine standard. Concentrations of GIP in plasma from 50 normal subjects after overnight fasting were 9 +/- 1.0 (S.E.M.) pmol/l rising to a peak of 34 +/- 2.8 pmol/l following the ingestion of a small mixed test meal. Ingestion of glucose or fat resulted in a similar rise of plasma GIP, whereas no change was observed after the ingestion of protein.

Adult↗
PubMed1980

The effect of antral distension in healthy subjects on betazole-stimulated gastric acid secretion and the plasma concentration of immunoreactive neurotensin.

Antral distension in seven healthy subjects had the same inhibitory effect, approximately 20% inhibition, on gastric acid secretion stimulated by pentagastrin and betazole (Histalog). The plasma concentration of neurotensin in peripheral venous blood was unchanged during antral distension in healthy subjects. The plasma concentration of neurotensin in portal blood was also unchanged during antral distension in anaesthetized duodenal ulcer patients and in non-ulcer patients. The inhibition of pentagastrin-stimulated gastric acid secretion by balloon distension of the antrum was unchanged by preceding intramuscular injection of metoclopramide. The inhibitory effect of antral distension on gastric acid secretion in healthy subjects does not seem to be mediated by secretin, cholecystokinin, bulbogastrone, neurotensin, or a dopaminergic mechanism.

Adult↗
PubMed1980

The effect of pirenzepine on meal-stimulated gastrointestinal hormones.

The effects of pirenzepine on the plasma concentrations of gut hormones in the fasting and postprandial states were studied in six healthy subjects. On separate days and in random order, 10 mg pirenzepine, in 2 ml of solvent, or 2 ml saline (0.15 mol/l) were given intravenously 30 min before a standard normal breakfast (2220 kJ). Pirenzepine was not found to affect basal or postprandial levels of insulin, glucagon, gastric inhibitory peptide (GIP), neurotensin, vasoactive intestinal peptide (VIP) or somatostatin. The basal concentration of pancreatic polypeptide (PP) was lowered (p less than 0.05) and the postprandial elevation reduced, though not significantly. While the basal concentration of motilin was also suppressed (p less than 0.05), the postprandial elevation remained unchanged following pirenzepine. The release of enteroglucagon was reduced significantly in the basal and postprandial states (p less than 0.05 and p less than 0.025 respectively). The postprandial gastrin response was prolonged slightly, but insignificantly, by pirenzepine. It is concluded that pirenzepine does not exert any major or unexpected actions on the hormonal control of digestion.

Adult↗
PubMed1980

Trifluoperazine reversal of secretory diarrhea in pancreatic cholera.

Diarrhea in a patient with pancreatic cholera syndrome caused by a vasoactive intestinal polypeptide producing pancreatic islet-cell carcinoma responded rapidly and dramatically to the phenothiazine trifluoperazine. Treatment with intravenous somatostatin decreased the plasma vasoactive intestinal polypeptide level without changing the diarrhea. The chemotherapeutic agent chlorozotocin, the 2-chloroethyl analogue of streptozocin, caused a decrease in plasma vasoactive intestinal polypeptide but caused significant renal toxicity with proteinuria.

Adenoma, Islet Cell↗
PubMed1980

Hormonal abnormalities of the pancreas and gut in cystic fibrosis.

We have investigated the effect of cystic fibrosis on alimentary hormones in 10 children by measuring the pancreatic and gut hormone rsponse to a milk drink. Plasma insulin and gastric inhibitory peptide were both significantly reduced (P < 0.05 and P < 0.005, respectively, at 15 min) in the patients with cystic fibrosis, compared with controls, even though the early glucose rise was greater in the former group (P < 0.05 at 15 min). Fasting levels of pancreatic polypeptide were significantly lower in the fibrocystic children (P < 0.01), and the normal response to milk was completely abolished in these patients (P < 0.001). Fasting plasma enteroglucagon concentrations were grossly abolished in the cystic fibrosis patients (P < 0.001) and these remained elevated throughout the test. No significant differences were seen in basal or postmilk responses of plasma glucagon, gastrin, secretin, vasoactive intestinal peptide, or motilin in cystic fibrosis. It would thus appear that the pancreatic polypeptide cell is more susceptible to the effects of the disease process than the beta or alpha cell in cystic fibrosis. Some aspects of the abnormalities in the gastrointestinal endocrine system were similar to those seen in celiac disease and tropical sprue and may, therefore, effect a similar hormonal response in these patients with cystic fibrosis to those with mucosal damage.

Adolescent↗
PubMed1980

Abnormalities of vasoactive intestinal polypeptide-containing nerves in Crohn's disease.

The possible involvement of nerves containing vasoactive intestinal polypeptide in Crohn's disease was investigated by immunocytochemistry and radioimmunoassay of specimens from 17 patients with well-defined clinical and histologic features of the disease. The characteristic pattern of slender fibers, evenly distributed across the gut wall, was seen in specimens taken from controls, which consisted of (a) specimens from uninvolved areas of gut from carcinoma resection (n = 17) and (b) jejunoileal specimens obtained during bypass operation for obesity (n = 8) as well as in four of the six specimens from patients with ulcerative colitis. In contrast, this characteristic pattern was lost in all 17 patients with Crohn's disease, the pattern being replaced by thickened and more intensely immunostained fibers. These changes were consistently found in the mucosa and submucosa, and in 13 of the Crohn's disease cases, the abnormal pattern was totally transmural, involving both the myenteric and submucous plexus as well as the muscle layers. There was a > 200% increase in VIP content, as determined by radioimmunoassay, in Crohn's disease (294 +/- 29 pmol/g wet wt, mean +/- SEM) in comparison with (a) ulcerative colitis (93 +/- 5 pmol/g [P < 0.001]), and (b) controls consisting of carcinoma resection (108 +/- 39) and bypassed gut from obese patients (86 +/- 27 [P < 0.001]). At least part of the previously documented autonomic nerve changes in Crohn's disease are, thus, due to an increase in vasoactive intestinal polypeptide innervation.

Adolescent↗
PubMed1979

Gut hormones in tropical malabsorption.

Concentrations of various gut hormones were measured after a test breakfast in eight patients with severe tropical malabsorption and 12 controls. The patients with tropical malabsorption had greatly raised basal plasma motilin and enteroglucagon concentrations, but their postprandial release of both gastric inhibitory polypeptide and insulin was significantly reduced. The pattern of gut hormone release differed from that found in coeliac disease. The measurement of gut hormones, each of which has a specific site and function, thus throws new light on the pathophysiology of tropical malabsorption and may suggest approaches of treatment.

Adult↗
PubMed1979

Combined use of guar and acarbose in reduction of postprandial glycaemia.

Symptoms associated with carbohydrate malabsorption limit the usefulness to diabetics of a powerful glycoside-hydrolase inhibitor (acarbose) which reduces postprandial glycaemia. Addition of a low dose (50 mg) of a acarbose together with 14.5 g guar gum to a breakfast test meal taken by 8 healthy volunteers reduced the mean peak rise in blood-glucose at 30 min by 70%. Areas under the insulin and gastrointestinal-polypeptide response curves were also greatly reduced. No evidence of carbohydrate malabsorption, as assessed by measurement of breath hydrogen, was found during any of the test periods. When acarbose was taken alone, 3 of the 8 subjects had troublesome symptoms and the 30 min rise in blood-glucose was reduced by only 28%. Thus, combination of these two agents effectively reduces the rate of carbohydrate absorption without increasing side-effects and may make combined acarbose and guar acceptable in the management of some diabetics.

Adult↗
PubMed1979

Suppression of pancreatic endocrine tumour secretion by long-acting somatostatin analogue.

A new long-acting octapeptide analogue of somatostatin, Des AA1,2,4,5,12,13 D Try8 somatostatin, has been tested in 8 patients with pancreatic endocrine tumours. The analogue given subcutaneously suppressed the tumour-derived hormones in patients with insulinomas, glucagonomas, and gastrinomas for up to 24 h. The prolonged action appeared to be the result of slow release from the injection site. No side-effects were observed. Studies of long-term administration of this new peptide are now warranted.

Adult↗
PubMed1979

Plasma trypsin in chronic pancreatitis and pancreatic adenocarcinoma.

We have used a simple and precise radioimmunoassay to measure trypsin in human plasma. Fasting plasma trypsin concentrations were extremely low in patients with chronic pancreatitis with steatorrhoea (5 +/- 2 ng/ml) when compared to healthy controls (86 +/- 7 ng/ml, p less than 0.001). In patients with chronic pancreatitis but no steatorrhoea basal plasma trypsin levels were similar to those of the normal controls (99 +/- 25 ng/ml). A small but significant postprandial rise in plasma trypsin concentrations was observed in normal subjects (mean increment 15 +/- 4%, p less than 0.005, paired t test) but was absent in patients with chronic pancreatitis with steatorrhoea. In contrast to exocrine deficient chronic pancreatitis, other malabsorptive conditions associated with steatorrhoea (active coeliac disease and acute tropical sprue) demonstrated mean fasting trypsin concentrations similar to controls. Patients with adenocarcinoma of the pancreas had basal trypsin concentrations similar to healthy subjects as did patients with adenocarcinoma of the stomach, colon, rectum, brochus, and breast. In some cases measurement of plasma trypsin may be of help in the differential diagnosis of steatorrhoea.

Adenocarcinoma↗
PubMed1979

Hypotrypsinaemia in diabetes mellitus.

Plasma trypsin concentrations were measured in 403 fasting diabetics and 106 healthy controls. Basal trypsin concentrations in the normal subjects were 88 +/- 6 ng/ml (mean +/- S.E.M.). Mean plasma trypsin concentrations in diabetics treated with diet alone (n = 74) were 45 +/- 2 ng/ml, while in a group of young (less than 35 years, n = 88) insulin-dependent diabetics, they were very low at 29 +/- 2 ng/ml and these levels were inversely related to insulin dosage. The findings may help in the understanding of the pathophysiological changes in the exocrine pancreas in the diabetic state and may also shed some light on the physiological interrelationship between the endocrine and exocrine pancreas.

Adolescent↗