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Biomedical subjects

J N Hunt

Publications and source records attributed to J N Hunt.

At least 55 records · Page 3Linked to original sources
PubMed1972

The slowing of gastric emptying by four strong acids and three weak acids.

1. Test meals of 750 ml. water containing a range of concentrations of hydrochloric, nitric, sulphuric, cyclamic (cyclohexylsulphamic), tartaric, L-ascorbic and citric acids were instilled into the stomachs of sixteen healthy subjects.2. The greater the concentration of an acid in the instilled meal, the greater was the volume of meal recovered after a fixed interval.3. For the weak acids, tartaric, ascorbic and citric, the concentrations which gave a recovery of 450 ml., out of the 750 ml. instilled, increased with increase in the molecular weight of the acid.4. For the strong acids, hydrochloric, nitric, sulphuric and cyclamic, the concentrations which gave a recovery of 450 ml., out of the 750 ml. instilled, were approximately equal. These concentrations were less than those for weak acids.5. The strong acids with high molecular weights were slightly more effective in slowing gastric emptying than were those with low molecular weights.6. The approximate equality of effectiveness of nitric, sulphuric and cyclamic acids to hydrochloric acid is attributed to the presence of chloride ion in the duodenal contents. Thus all the strong acids instilled produce an environment of hydrochloric acid around the receptor.7. A model for a duodenal receptor responding to acids is proposed.

Acetates↗
PubMed1970

Studies of the effect of metoclopramide and apomorphine on gastric emptying and secretion in man.

With oral and intravenous doses of metoclopramide there was no constant effect on the gastric emptying of test meals of glucose or sodium citrate, nor was secretion of acid by the stomach in response to test meals of glucose or sodium citrate affected. Apomorphine, in subnauseous doses (0.25 mg intravenously) slowed the gastric emptying of test meals containing sodium citrate, and 10 mg of intravenous metoclopramide abolished the slowing of gastric emptying caused by apomorphine.

Amides↗
PubMed1969

Sedative properties of simple analgesics.

1. An attempt has been made to assess under double blind conditions the sedative action of phenacetin, paracetamol, and aspirin by testing their ability to prolong sleep in the face of a rapidly filling bladder.2. The volume in the bladder on awakening was independent of the rate of urine formation.3. Although phenacetin prolonged sleep there was no corresponding increase in urine volume on awakening. Apparently phenacetin sensitized the bladder to the distending volume and reduced the rate of urine formation. It was unnecessary to postulate sedative action to explain the results.4. Paracetamol had no effect on the mean sleep interval or mean urine volume although the drug was not totally inactive since it increased the variance of the results for sleep interval and urine volume.5. Aspirin prolonged sleep interval, but this effect would be explained if it were an antidiuretic because there was no increase in urine volume on awakening.6. Apparently no sedative or hypnotic has been shown to increase the urine volume on awakening under similar conditions.

Acetaminophen↗
PubMed1969

The slowing of gastric emptying by nine acids.

1. Test meals containing a range of concentrations of nine different acids were given to twenty healthy subjects. The acids used were hydrochloric, acetic, lactic, tartaric, phosphoric, citric, propionic, butyric and hexanoic.2. The greater the concentration of acid in the meal the greater was the volume of the meal recovered after a fixed interval.3. A rectilinear relationship between the mean concentrations of acid (m-equiv/l.) required to give a recovery of 450 ml. and the molecular weights of the acids used was found. The acids with high molecular weights were less effective than those with low molecular weights.4. The results indicate that the molecular weights of the anions play the dominant part in determining the effectiveness of the various acids. Slowing of gastric emptying by acids does not seem to be dependent upon their pK values provided they are less than 5. The oil/water partition coefficients are also apparently irrelevant to effectiveness.5. These findings are considered to be consistent with the view that a barrier to movement of the anions in an aqueous system limits the access of the hydrogen ions to duodenal receptors, which activate the mechanism slowing gastric emptying.

Acetates↗
PubMed1968

The slowing of gastric emptying by monosaccharides and disaccharides in test meals.

1. Test meals containing various concentrations of glucose, maltose, sucrose, fructose, lactose, galactose and mixtures of these solutes were given to six healthy subjects. All meals contained 40 mM sodium citrate.2. The slowing of gastric emptying produced by the disaccharides in test meals was generally consistent with the stimulation of duodenal osmoreceptors occuring after the hydrolysis of the disaccharides.3. Glucose was slightly more effective, per osmole, in slowing gastric emptying than was galactose.4. By comparison with glucose or galactose, fructose was much less effective in slowing gastric emptying. In three subjects out of six there was a threshold for its effect.5. The results may be indicative of the relative activities of disaccharidases in the brush border of the small intestine. They are consistent with there being an osmoreceptor deep to these enzymes which slows gastric emptying.

Adult↗
PubMed1968

A relation between the chain length of fatty acids and the slowing of gastric emptying.

1. Test meals of solutions and suspensions of potassium and sodium salts of a series of saturated fatty acids, from C(2) to C(18), were given to healthy subjects.2. From the volume of these meals recovered after a fixed interval the relative effectiveness of the salts of the acids in slowing gastric emptying was assessed.3. On a molar basis the salts of fatty acids from acetic up to decanoic were relatively ineffective in slowing gastric emptying.4. The salts of fatty acids with 12-18 carbon atoms were much more effective than those with up to 10 carbon atoms. Myristate was the most effective of the salts.5. Buffering the test meals with 33 mM sodium citrate increased the effectiveness of the salts in slowing gastric emptying.

Acetates↗