Search PubMed⌕ Search

Biomedical subjects

S R Bloom

Publications and source records attributed to S R Bloom.

At least 991 records · Page 55Linked to original sources
PubMed1981

The distribution of nine peptides in rat spinal cord with special emphasis on the substantia gelatinosa and on the area around the central canal (lamina X).

The comparative distribution of nine peptides was examined in the L4 segment of the rat cord using the peroxidase antiperoxidase technique. The peptides examined were substance P, neurotensin, cholecystokinin, methionine-enkephalin, oxytocin, neurophysin, adrenocorticotrophin, thyrotropin releasing hormone, and vasoactive intestinal polypeptide. No transport blocking agents were used and in spite of this cell bodies containing substance P, neurotensin, cholecystokinin, and methionine-enkephalin were observed. All peptides except for thyrotropin releasing hormone were observed in fibers in laminae I and II. All peptides were present in the area around the central canal, lamina X. Each peptide had its own characteristic distribution within fibers in the gray and white matter.

Adrenocorticotropic Hormone↗
PubMed1981

Vipergic nerves in the penis.

High concentrations of vasoactive intestinal polypeptide (VIP) were detected by immunocytochemistry and radioimmunoassay in thirty surgical specimens of male external genitalia. VIP was found exclusively in fine autonomic nerves. VIPergic nerves were most densely concentrated in the penis around the pudendal arteries and in the erectile tissue of the corpus cavernosum. Considerable numbers of VIP nerve fibres were also seen in the vas deferens and epididymis. VIP is known to exert regulatory actions on blood-flow, secretion, and muscle tone. Its presence in considerable amounts in the male genital tract suggests that this newly discovered peptide neurotransmitter may be important in the nervous control of male external genitalia.

Adult↗
PubMed1981

Clinicopathological study of pancreatic and ganglioneuroblastoma tumours secreting vasoactive intestinal polypeptide (vipomas).

During a six-year period (1973-9) 52 patients with pancreatic tumours and 10 with ganglioneuroblastomas were found to have raised plasma vasoactive intestinal polypeptide (VIP) concentrations. All the patients had severe secretory diarrhoea, weight loss, dehydration, hypokalaemic acidosis, and a raised plasma urea concentration. Reduced gastric acid secretion was seen in 72% of patients. Plasma VIP concentrations were not raised in patients with diarrhoea due to other types of tumour or disease or in hormone-secreting tumours not associated with diarrhoea. Plasma VIP measurement may therefore give clinical guidance in a patient with persistent watery diarrhoea and hypokalaemic acidosis. Surgical excision was clearly the treatment of choice, but metastatic pancreatic tumours usually responded to streptozotocin.

Adult↗
PubMed1981

Neuron-specific enolase is produced by neuroendocrine tumours.

Neuron-specific enolase (NSE) is a neuronal form of the glycolytic enzyme enolase, which was first found in extracts of brain tissue, and was later shown to be present in APUD (amine precursor uptake and decarboxylation) cells and neurons of the diffuse neuroendocrine system but not in other peripheral cells. 90 neuroendocrine neoplasias (APUDomas) (including islet-cell tumours, phaeochromocytomas, medullary thyroid carcinomas, oat-cell tumours, and APUDomas of the gut, pancreas, and lung) reacted strongly with antisera to NSE. In addition, large amounts of the enzyme were found by radioimmunoassay in the tumours (mean 1626 +/- 479 SEM ng of NSE/mg protein), whereas control non-endocrine neoplasias contained less than 15 ng NSE/mg protein. Thus NSE, a specific enzyme produced in the neural and endocrine systems, was found to be produced in considerable quantities by all types of APUDomas but not in any non-endocrine tumours. NSE seems to be a useful and easily detected marker which may be used to distinguish endocrine from nonendocrine neoplasias. Clinical detection of endocrine tumours is difficult and such tumours are often missed. Use of NSE as a marker may avoid this.

Apudoma↗
PubMed1981

Release of vasoactive intestinal peptide in the dumping syndrome.

To determine the effect of gastric surgery on the plasma vasoactive intestinal peptide (VIP) concentration, 13 patients with gastrectomy and seven controls were given an oral hypertonic load (200 ml 50% glucose solution). Blood was taken at intervals during the test for measurement of VIP and blood glucose concentrations and packed cell volume. At the same time observations were made on the occurrence of dumping symptoms and a record kept of the pulse rate. VIP values in the patients with gastrectomy were significantly increased by glucose ingestion, while these did not alter in controls (p less than 0.001). There was a highly significant correlation between the rate of rise in plasma VIP concentration and the rates of rise in packed cell volume (r = 0.85; p less than 0.001) and blood glucose concentration (r = 0.76; p less than 0.01) in patients with gastrectomy. Changes in packed cell volume and blood glucose values and the occurrence of dumping symptoms during the test were significantly different when postoperative patients were compared with controls (p less than 0.001, p less than 0.005, and p less than 0.001 respectively). Furthermore, when the patients with gastrectomy were divided into those without symptoms and those with dumping after meals the latter group showed a significantly greater rise of VIP (p less than 0.05). Despite the increased plasma VIP concentrations observed during dumping, VIP cannot be taken as the sole factor in the pathogenesis of the dumping syndrome.

Aged↗
PubMed1981

The effects of caerulein and a meal stimulus on gallbladder intraluminal pressure and bile flow in the pig.

The intraluminal gallbladder pressure has been measured in a conscious unsedated pig model by the use of a radiotelemetry pressure capsule. A loop fistula was incorporated to measure bile output simultaneously. Mean fasting intraluminal gallbladder pressure was found to be 15 +/- 4 mmHg above atmospheric pressure, and mean fasting bile output 7.5 +/- 0.8 ml/10 min. Following intravenous caerulein pressure peaked at 2 min with a mean rise of 17 +/- 3 mmHg above basal (P less than 0.005). Bile output was increased for 30 min following caerulein with a total mean increase for this period of 13.5 +/- 2.2 ml (P less than 0.005). Gallbladder pressure rose significantly 5 min after commencing a meal by 6.0 +/- 1.9 mmHg (P less than 0.025) reaching a peak pressure 65 min after the meal with a mean rise of 14.8 +/- 2.3 mmHg (P less than 0.005). Bile output was significantly increased for 50 min following the ingestion of food. The total increments above basal values for bile output being 15.9 +/- 2.7 ml (P less than 0.005) in the first 30 min post-prandially and 1.6 +/- 2.4 ml (P less than 0.005) in the 30--60 min period. This model re-emphasizes the rapidity of the hormonal response and may be valuable for further studies on the physiology of post-prandial gallbladder emptying.

Animals↗
PubMed1981

The influence of an intact pylorus on postprandial enteroglucagon and neurotensin release after upper gastric surgery.

Upper partial gastrectomy for carcinoma of the gastric cardia or fundus is unavoidably accompanied by truncal vagotomy, so it is orthodox practice to carry out pyloroplasty with this procedure. In order to assess the effect of leaving an intact pylorus in this operation, 21 patients were investigated with an oral hypertonic load (200 ml 50 per cent glucose solution), and blood was taken at intervals during the test, for the ileal gut hormones, enteroglucagon and neurotensin, as well as for measurements of haematocrit and blood glucose. Clinical features of dumping during the test were sought. There were 7 patients with upper partial gastrectomy, truncal vagotomy and an intact pylorus, 7 patients without a pylorus (total or near total gastrectomy) and 7 patients not subjected to gastric surgery. No significant difference was found in any of the measurements between gastrectomy patients with an intact pylorus and those draining through an enterostomy. However, both these groups differed significantly from normal controls in having greater rates of rise and higher peak values of enteroglucagon, neurotensin, haematocrit and blood glucose, together with a more frequent occurrence of dumping symptoms during the test. As the above measurements probably reflect transit of glucose into the small intestine, the findings in this study suggest that leaving an intact unstenosed pylorus is unlikely to lead to gastric stasis following upper partial gastrectomy.

Aged↗
PubMed1981

Vasoactive intestinal polypeptide (VIP)-like immunoreactivity in anuran intestine.

Immunocytochemical and radioimmunological techniques with region specific antisera have been used to identify a vasoactive intestinal polypeptide-like material in the anuran intestine. Seven species of Anura were investigated: Bombina bombina, Alytes obstetricans, Rana temporaria, Rana esculenta, Hyla arborea, Hyla crepitans and Bufo bufo. In five of the species (A. obstetricans, R. temporaria, H. arborea, H. crepitans and B. bufo) vasoactive intestinal polypeptide-like immunoreactive mucosal endocrine cells and nerve fibres in all layers of the gut wall, were detected by both immunofluorescence and peroxidase-antiperoxidase methods. In the other two species, R. esculenta and B. bombina, no mucosal endocrine cells were detected although the vasoactive intestinal polypeptide-immunoreactive nerve fibres were plentiful. Radioimmunoassay showed the presence of significant amounts of vasoactive intestinal polypeptide-immunoreactivity in intestinal extracts from all species. The highest quantities were present in those anurans with both immunostained cells and nerves. Gel permeation chromatography showed that most of the vasoactive intestinal polypeptide-like peptide eluted in a position identical to that of natural mammalian (porcine) vasoactive intestinal polypeptide. The results indicate that a vasoactive intestinal polypeptide-like peptide is well represented in the Anura and that it is immunologically very similar to the mammalian peptide.

Animals↗
PubMed1981

Plasma vasoactive intestinal polypeptide and other regulatory peptides in children with neurogenic tumours.

Plasma regulatory peptide levels were studied in a group of 21 children with neurogenic tumours and in 22 control children. Plasma vasoactive intestinal polypeptide (VIP) levels were significantly higher in children with neurogenic tumours than in normal children or those with other tumours (p less than 0.05). There was no significant difference between the groups in plasma levels of gastrin, pancreatic glucagon or pancreatic polypeptide. The plasma VIP level may thus be a helpful diagnostic marker for neurogenic tumours in children.

Adolescent↗
PubMed1981

Intractable diarrhoea in a patient with vasoactive intestinal peptide-secreting neuroblastoma. Attempted control by somatostatin.

A 1 1/2 year old child developed profuse watery diarrhoea, shown to be due to excessive plasma vasoactive intestinal peptide (VIP) levels, whilst on treatment for metastatic neuroblastoma. Because it was unresponsive to alternative treatment, an attempt was made to control the diarrhoea with a somatostatin infusion. The attempt failed despite the fact that serum VIP levels were substantially reduced. Possible reasons for failure are discussed and the importance of plasma VIP as a marker for maturation in neuroblastoma emphasised.

Diarrhea↗
PubMed1981

Colonic inhibition of gastric secretion in man.

The effect of colonic infusion of various solutions on submaximal pentagastrin-stimulated gastric secretion was determined in healthy volunteers. Hypertonic (823 mOsm/kg) glucose, mannitol, and saline, and also isotonic glucose significantly induced a marked and sustained inhibition of gastric acid secretion of 74%, 66%, 79%, and 54%, respectively. A similar degree of inhibition was obtained for pepsin secretion with hypertonic glucose and mannitol. Isotonic triglycerides and isotonic saline solutions had no significant effect on gastric acid secretion. Hypertonic glucose, mannitol, and saline infusions significantly increased plasma concentrations of enteroglucagon, whereas other solutions had no effect. No correlation, however, was found between the percentage rise of enteroglucagon and the percentage inhibition of gastric secretion obtained from any of the three hypertonic solutions. The physiological significance of these findings remains to be established.

Adult↗
PubMed1981

A qualitative comparison of canine plasma gastroenteropancreatic hormone response to bombesin and the porcine gastrin-releasing peptide (GRP).

The effect on plasma gastroenteropancreatic hormone levels on infusing the porcine gastrin-releasing peptide and bombesin into dogs demonstrated no qualitative difference in the spectrum of activity of the two peptides. Sustained elevation in plasma immunoreactive gastrin, pancreatic polypeptide, enteroglucagon, gastric inhibitory polypeptide, pancreatic glucagon and transient elevations in plasma insulin were seen during infusions of both peptides. The similar spectrum of activities and the structural homology between the two peptides suggests that the porcine gastrin releasing peptide is the porcine counterpart of the amphibian peptide bombesin.

Animals↗
PubMed1981

Characterisation of gut hormone storage granules from normal human jejunum using metrizamide density gradients.

Analytical subcellular fractionation techniques using metrizamide density gradients have been used to investigate the properties of the gut hormone storage granules and the principal organelles from homogenates of normal human jejunal mucosa obtained by peroral mucosal biopsy. The individual hormones, detected by radioimmunoassay, each showed single discrete peaks in the density gradient experiments indicating localisation to single granules each with characteristic modal densities. Thus motilin showed a modal density of 1.15, gastrin 1.16, gastric inhibitory polypeptide (GIP) 1.17, enteroglucagon 1.18 and somatostatin and vasoactive intestinal peptide (VIP) 1.10 g/ml. The following organelles, characterised by their marker enzymes were located in the density gradients; plasma membrane (5'-nucleotidase) brush border (alpha-glucosidase, pH 6.0) mitochondria (particulate malate dehydrogenase), peroxisomes (catalase), lysosomes (N-acetyl-beta-glucosaminidase), endoplasmic reticulum (alpha-glucosidase, pH 8.0), cytosol (lactate dehydrogenase). These studies provide biochemical evidence of the distinct nature of the individual gut hormone storage granules and provide a basis for studying dynamic changes in the granules in response to physiological stimuli and pathological processes.

Adult↗