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Biomedical subjects

J N Hunt

Publications and source records attributed to J N Hunt.

At least 37 records · Page 2Linked to original sources
PubMed1978

The slowing of gastric emptying by proteins in test meals.

1. Test solutions containing either glucose, casein, partially hydrolysed gelatin or egg albumin, native or denatured, at concentrations up to 50 g/l. in 33 mM-trisodium citrate solution, were given by tube into the stomachs of nine subjects in volumes of 600 or 750 ml. 2. The volume of the test solution recovered from the stomach after 20 min was measured. 3. The greater the concentration of solute the greater was the volume of the test solution recovered. 4. Gram for gram, gelatin hydrolysate was equivalent to glucose in slowing gastric emptying. Casein was slightly more effective than glucose and native egg albumin was less effective than glucose. 5. The results were explained by assuming that the products of hydrolysis of proteins stimulated osmoreceptors in the walls of the duodenum. 6. The results were in line with the suggestion that proteins in food contribute to the slowing of gastric emptying in such a way that isocaloric amounts of carbohydrate and mixed protein have the same effect. 7. There was a strong correlation between the concentration of glucose giving a recovery of 400 ml. and the corresponding concentration of casein within-subject, but there was no such relationship for gelatin hydrolysate. It was concluded that the between-subject variability in the digestion of casein was small, that for gelatin hydrolysate was large.

Adult↗
PubMed1978

Glucose, glycine and diglycine in test meals at stimuli to a duodenal osmoreceptor slowing gastric emptying.

1. Five subjects took 210 test meals of 750 ml. water containing 30--300 m-molal glucose or glycine, or 15--150 m-molal diglycine, or plain water. 2. The greater the concentration of solute, the greater was the volume of original meal recovered from the stomach after a fixed time. 3. On a molal basis glucose was half as effective as diglycine in slowing gastric emptying. This was consistent with the osmoreceptor being exposed to the diglycine after it had been split by the hydrolase of the cytosol of enterocytes (the absorbing cells of the small intestine). 4. The slowing of gastric emptying (ml./mole.1.) was about 10% greater for glycine than it was for glucose. There was apparently a threshold concentration below which glycine did not slow gastric emptying. 5. It was proposed that the response of the doudenal osmoreceptor might depend upon shrinking and swelling of the lateral intercellular space around the enterocytes.

Chemoreceptor Cells↗
PubMed1978

Relation between volume swallowed and velocity of the bolus ejected from the pharynx into the esophagus.

The velocity of the front face of a liquid saline bolus ejected from the pharynx into the esophagus was measured by recording changes of luminal electrical impedance with three sets of electrodes in 9 subjects. At a site 26 cm from the incisors, the mean velocity of the front face of the bolus increased from 10 to 70 cm sec-1 as the volume swallowed was raised from 5 to 30 ml. The velocity of the front face of the bolus was greater 26 cm from the incisors than it was 32 cm from the incisors.

Deglutition↗
PubMed1977

Effects of hydrochlorides of amino acids in test meals on gastric emptying.

Four subjects were given test meals containing various concentrations of hydrochlorides of glycine, alanine, arginine, phenylalanine and tryptophan. The gastric contents were recovered after 20 min. The volume of the original meal recovered was assessed from the amount of marker substance aspirated. It was found that the slowing of gastric emptying of amino acid hydrochlorides was consistent with their action as weak acids. However, tryptophan and phenylalanine were slightly more effective than was predicted on the basis of their actions as acids.

Amino Acids↗
PubMed1976

A sensitive method for measuring haemoglobin in gastric contents.

A sensitive method for measuring haemoglobin in gastric contents using the rate of change of optical density of a mixture of orthotolidine and hydrogen peroxide in the presence of haemoglobin, is described. The method can measure the blood normally lost in 10 min from the gastric mucosa.

Benzidines↗
PubMed1975

Energy density of food, gastric emptying, and obesity.

An investigation of gastric emptying suggested that people choosing an energy-dense mixture of dood and drink have an empty stomach sooner--and might, therefore, eat more--than people who take their energy in more dilute form. Support for the notion that energy density (kcal divided by volume of food and drink) might be related to relative body-weight comes from a study in healthy males. A proportion, albeit a small one, of the variance in relative body-weight (Quetelet) could be ascribed to energy density, and the relationship was stronger among the more obese men.

Adult↗
PubMed1975

The volume and energy content of meals as determinants of gastric emptying.

1. Results were collected from thirty-three published and unpublished studies of gastric emptying. The volumes of the meals ranged from 50 to 1250 ml., and composition varied from pure carbohydrates to ordinary food. 2. From the published composition of the meals, their nutritive density, as kcal/ml. (4-18 KJ/ml.) was computed: it ranged from zero to 2-3 kcal/ml. 3. The volume of each meal, or test meal, delivered to the duodenum in 30 min was determined, assuming that gastric emptying was exponential. 4. The greater the nutritive density of a meal, the less was the volume transferred to the duodenum in 30 min. The original volume of meal given was not a determinant of the rate of emptying (ml./min). 5. The slowing of gastric emptying with a meal of high nutritive density was not sufficient to prevent an increased rate of delivery of energy to the duodenum (nutritive density times volume delivered in unit time) with a meal of high nutritive density. 6. Assuming an appropriate relationship for the interaction of a stimulus (kcal/ml.) and duodenal receptors, it was possible to predict a rate of gastric emptying for each meal, given its nutritive density. Knowing the initial volume of the meal, it was possible to predict the mean half time for its emptying. 7. There were eight sets of anomalous results: in four the volumes of meal given were less than 200 ml.; explanations of the anomalies in the other four results could not be provided. 8. The results are consistent with equal slowing of gastric emptying by the duodenal action of the products of digestion of isocaloric amounts of fat, protein and carbohydrate, for example, 4 g fat or 9 g carbohydrate, both 36 kcal, taking carbohydrate and protein as 4 kcal/g and fat as 9 kcal/g.

Dietary Carbohydrates↗
PubMed1975

A relation between the energy of food and gastric emptying in men with duodenal ulcer.

Using information about the volume and energy density of meals, results from the literature on gastric emptying for healthy men can be marshalled into a consistent body. The same process applied to the published papers on men with duodenal ulcer shows that they have abnormally rapid gastric emptying, especially for meals of high-energy density. This provides confirmation of the view of Shay (1944) that the slowing of gastric emptying by duodenal receptors is less in men with duodenal ulcer than it is in healthy men.

Duodenal Ulcer↗
PubMed1974

Actions of glucose and potassium chloride on osmoreceptors slowing gastric emptying.

1. Five subjects were given 373 test meals of 750 ml. water containing a range of concentrations of glucose or potassium chloride.2. The greater the concentration of solute in the meals, the greater was the volume of the test meal recovered from the stomach after a fixed time.3. When the concentrations of the solutes were expressed as m-osmole/l. corrected by osmotic coefficients based on vapour pressures at 37 degrees C, glucose and potassium chloride were indistinguishable in slowing gastric emptying.4. These results are consistent with the regulation of gastric emptying by a duodenal receptor responding to osmotic pressure.5. Potassium chloride was more nauseating than glucose on an osmolar basis.

Duodenum↗
PubMed1973

The effect of citric acid and its sodium salts in test meals on the gastric outputs of acid and of chloride.

Five subjects were given 750 ml. test meals lasting 10-20 min, containing 0-300 mN citric acid, monosodium dihydrogen citrate, disodium monohydrogen citrate or trisodium citrate.1. Increase in concentration of sodium citrate in the range 0-125 mN gave increasing outputs of acid and chloride.2. The more acid the meal for any given citrate ion concentration, the less the output of acid and chloride.3. The greater the concentration of an acid citrate salt, the less the output of acid.4. There was evidence of loss of acid from the stomach by diffusion with the more acid meals.

Chlorides↗
PubMed1972

Effect of a hot milk drink on movements during sleep.

The effects on sleep of a hot drink of milk and Horlicks were compared with those of hot water taken before retiring by medical student volunteers. Horlicks reduced the number of small movements made during sleep.

Adult↗