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Biomedical subjects

N S Track

Publications and source records attributed to N S Track.

At least 37 records · Page 2Linked to original sources
PubMed1982

Sustained pectin ingestion delays gastric emptying.

The effects of sustained fiber ingestion on gastric emptying glucose tolerance, hormone responses, and jejunal absorption of glucose and lysine were studied in healthy volunteers. Subjects were placed on a low-fiber (3 g) diet for 2 wk, followed by 4 wk of an isocaloric diet supplemented with 20 g/day of either apple pectin (7 subjects) or alpha-cellulose (6 subjects). At the conclusion of each dietary period subjects ingested a low-fiber breakfast surface-labeled with 99mtechnetium sulfur-colloid. Gastric emptying half-time, plasma glucose, calcium, phosphorus, insulin, glucagon, gastrin, human pancreatic polypeptide, and motilin were determined. Gastric emptying half-time was prolonged approximately twofold after pectin supplementation (p less than 0.005) and returned to normal 3 wk after discontinuing pectin supplementation. Cellulose supplementation did not alter the gastric emptying rate. Plasma glucose, calcium, phosphorus, and hormonal responses to the meal were unchanged after either pectin or cellulose supplementation. Pectin ingestion did not impair intestinal absorption of glucose or lysine. In contrast to sustained cellulose ingestion, sustained pectin ingestion slows the gastric emptying rate; the mechanism underlying this adaptive effect is unknown.

Adolescent↗
PubMed1981

Diets rich in natural fibre improve carbohydrate tolerance in maturity-onset, non-insulin dependent diabetics.

The influence of low and high fibre diets upon carbohydrate tolerance was examined in five maturity-onset, non-insulin dependent diabetics. After 14 days on a diet rich in natural fibre (30 g/day), the subjects consumed a high fibre (13 g) test meal. They then ate a low fibre diet (10 g/day) followed by a low fibre (1 g) test meal. Mean basal plasma glucose concentrations were similar after both fibre diets; however, both mean basal plasma insulin and gastric inhibitory polypeptide (GIP) were significantly lower after the high fibre diet. After the high fibre test meal, significantly lower mean plasma glucose, insulin and GIP concentrations were measured. This study is the first study to demonstrate the ability of an institutionally supervised diet of natural foodstuffs rich in fibre to improve carbohydrate tolerance in maturity-onset, non-insulin dependent diabetics. This findings is relevant to the dietary management of diabetics.

Aged↗
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

Initiation of migrating myoelectric complexes in human subjects: role of duodenal acidification and plasma motilin.

The hypothesis that acid, emptied intermittently from the stomach during fasting, might initiate the duodenal phase of the migrating motor complex was tested in normal human subjects. In addition, the relationship between plasma motilin concentrations and the initiation of migrating motor complexes was examined. Migrating complexes occurred spontaneously in the absence of acid in the duodenal bulb and in the presence of duodenal bulb neutralization with sodium bicarbonate. Thus duodenal bulb acidification is not necessary for initiation of the duodenal phase of the migrating motor complexes. Furthermore, cyclical increases in plasma motilin concentrations were not closely correlated with the initiation of the gastric phase of maximal activity of the migrating motor complexes. However, motilin concentrations were decreased significantly following onset of the duodenal phase III. We conclude that neither duodenal acidification nor increases in motilin concentration are necessary to initiate migrating motor complexes in man.

Adult↗
PubMed1981

Changes in plasma motilin concentration in response to manipulation of intragastric and intraduoduenal contents in man.

Immunoreactive plasma motilin concentrations were studied following a variety of stimuli in 24 healthy fasting subjects. Plasma motilin was measured by a radioimmunoassay using antibody GP 71 (J. C. Brown) and natural porcine motilin as standard. Basal motilin levels ranged from undetectable to 365 pg/mL. Antral and intraduodenal infusion of 50 mL o.1 N HCl (pH 1.2) at 5 mL/min failed to alter significantly plasma motilin levels but duodenal acid infusions at 17 mL/min caused a significant increase (70.8 +/- 29.5 pg/mL, mean +/- SEM; n = 6), maximal at 40 min. Duodenal alkalinization with 50 mL 0.3 M Tris buffer (pH 8.0) infused at 5 mL/min produced no change in plasma motilin. A mixed meal did not affect plasma motilin levels. Ingestion of 60 g fat significantly increased plasma motilin (n = 13; maximal increase 150.3 +/- 43.3 pg/mL at 30 min) but duodenal infusions of fat failed to increase plasma motilin levels. These results suggest that motilin secretion induced by fat requires that the fat be present initially within the stomach for secretion to occur. We conclude that ingested fat is a potent stimulus of motilin release. As duodenal acidification (50 mL 0.1 N HCl over 10 min) induces duodenal activity resembling migrating motor complexes but does not release motilin, our data argue against the release of motilin following duodenal acidification as a trigger for the initiation of these complexes in man.

Adult↗
PubMed1980

The gastrointestinal endocrine system.

Gastrointestinal endocrinology is the study of the hormonal regulation of digestion. A number of characterized polypeptide hormones have been localized in specific gastroenteropancreatic endocrine cells. The fact that some of these hormones are also found in nerve and brain cells has given rise to the concept of a gut-brain axis. The functional capacities of these endocrine cells are determined by their anatomic location; the luminal exposure of gastroenteric endocrine cells represents an additional avenue for stimulation and release that is not open to pancreatic endocrine cells. Gastroenteropancreatic hormones regulate carbohydrate metabolism, gastric acid secretion, pancreatic exocrine and gallbladder function, gastrointestinal motility and blood flow. These important regulatory hormones may in turn be controlled by a series of gastroduodenal releasing hormones.Diabetes mellitus is the most important metabolic disorder related to a gastroenteropancreatic hormone imbalance. Most tumours producing these hormones are of pancreatic origin and produce a number of hormones; insulinomas and gastrinomas are detected readily because of the serious metabolic distrubances they cause. Other instances of altered circulating concentrations of these hormones result from rather than cause the disease.The challenge of future study is to determine if postprandial changes in the plasma concentrations of these hormones are sufficient or necessary, or both, for the control of digestion.

Carbohydrate Metabolism↗
PubMed1980

Human pancreatic polypeptide: studies of fasting and postprandial plasma concentrations.

Circulating human pancreatic polypeptide (HPP) was studied in 16 human subjects during two 24-h test periods, one fasting and another eating meals at 0830, 1230, and 1730. In six subjects the tests were repeated with propantheline administration. Blood was sampled every 30 min; additional blood samples were drawn 15 and 45 min postprandially. Mean HPP concentrations increased gradually during the day in 13 out of 16 fasting subjects, reaching an average peak at 2100. By 0200 mean HPP concentrations returned to initial fasting concentration. Propantheline eliminated this circadian rhythm. Biphasic plasma HPP responses were recorded after each of the three meals during the test. Calculation of integrated HPP outputs revealed similar outputs to the three meals; the percentage contribution of the first release phase increased with successive meals. Propantheline caused a 60% decrease in integrated HPP outputs. The first release phase was practically absent after the 0830 meal; however, distinct biphasic responses were present after the 1230 and 1730 meals. These studies demonstrate that fasting plasma HPP displays a cholinergic-dependent circadian rhythm, that postprandial plasma HPP responses are quantitatively similar throughout the day, and that different cholinergic activities are involved in the maintenance of these fasting and postprandial plasma HPP patterns.

Adult↗
PubMed1980

The gastroplasty tube and its role in reflux control: an experimental and clinical study.

The gastroplasty tube has been used in the control of reflux since it was originally described by Collis in 1961. Several variations of the procedure have been reported indicating a low frequency of anatomic recurrence but a high frequency of reflux. Two forms of gastroplasty procedure are used: partial fundoplication in which gastric fundus incompletely wraps the gastroplasty and high pressure zone, and total fundoplication in which a circumferential wrap is constructed. The authors conducted a clinical review, using the patient's history, radiology and manometry, of 135 patients with partial fundoplication gastroplasty (PFG) and 250 patients with total fundoplication gastroplasty (TFG). In both groups the anatomic recurrence rate was low; however, with PFG the frequency of reflux was 44.6% and 25.7% of patients had notable symptoms. With TFG no patient had reflux. The response of the gastroplasty tube to meal-induced gastrin release and to neurogenic stimulation was tested. Basal tube pressure was low and showed no response to gastrin release and no augmented neurogenic response. It was concluded that the gastroplasty tube did not have intrinsic properties of value in controlling reflux and that reflux control depended upon the method of fundoplication. The role of the gastroplasty tube is in preventing anatomic recurrence.

Eating↗
PubMed1979

Motilin, human pancreatic polypeptide (HPP) and gastrin plasma concentrations in fasting subjects.

Motilin, human pancreatic polypeptide (HPP) and gastrin plasma concentrations have been determined in 196 fasting subjects ranging in age from the third to ninth decade. Detailed descriptions of the motilin, HPP and gastrin radioimmunoassays are presented. Plasma motilin concentrations ranged from undetectable to 1253 ng/L with a median value at 157 ng/L. Age and sex did not influence plasma motilin concentrations. Plasma HPP concentrations ranged from undetectable to 1564 ng/L with a median value at 142 ng/L. Plasma HPP concentrations increased significantly with age; males generally had higher concentrations than females. Plasma gastrin concentrations ranged from undetectable to 1658 ng/L with a median value of 21 ng/L. Age and sex did not influence plasma concentrations. These data establish ranges for plasma motilin, HPP and gastrin in fasting subjects aged 21--90 years using the described radioimmunoassays.

Adult↗
PubMed1979

Extraordinary hyperbilirubinemia in a neonate with idiopathic hypertrophic pyloric stenosis.

This case describes an extraordinarily elevated total bilirubin level that reverted to normal 9 1/2 wk after Fredet-Ramstedt pyloromyotomy. Although the etiology of jaundice occurring in patients with IHPS remains uncertain, theories implicating inhibition of the glucuronyl transferase system have been proposed. Infants with IHPS have a documented hypergastrinemia. An hypothesis is offered, illustrated by this case, to explain the inhibition of the glucuronyl transferase system with resultant hyperbilirubinemia by the hypergastrinemia of idiopathic hypertrophic pyloric stenosis.

Exchange Transfusion, Whole Blood↗
PubMed1979

Appearance of gastrin and somatostatin in the human fetal stomach, duodenum and pancreas.

The gestational time of appearance of gastrin and somatostatin in the human fetal stomach, duodenum and pancreas was examined. Immunoreactive gastrin (IRG) is detected in antral, duodenal and pancreatic extracts of a 7.0-cm (crown-heel length) fetus. More IRG is extracted from the duodenum than the antrum. Duodenal IRG concentration from fetuses of 16.0--26.0 cm are higher than younger fetal and adult concentrations. Antral IRG concentrations are one tenth of the adult contents. Very small IRG concentrations are present in the human fetal pancreas. Gastrin immunohistochemical staining is positive first in duodenal (6.5-cm fetus) and later in antral (12.5-cm fetus) mucosa; pancreatic tissue is negative for gastrin immunohistochemistry. Type IV cells are encountered in antral and duodenal mucosa of 4.0-cm fetuses; other endocrine cells appear with fetal growth. Not until much later in gestation (21.0 cm) do typical G cells appear. These results suggest that early in fetal life gastrin is produced by the type IV cell. Somatostatin immunohistochemical staining is positive in stomach, duodenum and pancreas in 6.5-cm fetuses. Immature D cells are found in antral and duodenal mucosa of 5.0-cm fetuses and mature D cells in 11.0-cm fetuses.

Chromatography, Gel↗