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Biomedical subjects

J T Hamilton

Publications and source records attributed to J T Hamilton.

68 records · Page 4Linked to original sources
PubMed1967

A controlled clinical trial using placebos in normal subjects: a teaching exercise.

An exercise for medical students was designed to illustrate one method of setting up a clinical trial and incidentally to demonstrate some effects of placebos. Twelve groups of four students participated: one in each group was the "recorder", the other three (volunteers) were randomly assigned to the treatment A, treatment B, or untreated groups. Subjects performed seven psychomotor or mental tests before taking medication and 30 and 60 minutes after medication. The time taken for the tests and the errors made were recorded. Treatment A was one green and yellow gelatin capsule filled with lactose, taken with water; treatment B was a red and white capsule containing lactose; untreated subjects received a drink of water. No large changes in performance occurred and no evidence of fatigue or learning was noted, although the B's took significantly longer to perform the arithmetic test after medication than before. Treated subjects were instructed to check any of 29 listed side effects that they experienced. A total of 44 side effects was reported: 8 of 12 in A group and 10 of 12 in B checked one or more symptoms. Indications are that the results of the trial will not soon be forgotten.

Adult↗
PubMed1966

A comparison of the effects of chlorothiazide, quinethazone and placebo on student volunteers and on rats: a teaching exercise.

Medical student participation in a controlled doubleblind clinical bioassay provides an effective introduction to clinical pharmacology and perhaps the best stimulus to the future rational evaluation and use of drugs. In one such exercise, 27 volunteers were divided into three groups: one received 50 mg. quinethazone, one 500 mg. chlorothiazide and the third a lactose placebo. Urine was collected for three 90-minute periods, volume and pH being recorded; sodium and potassium were measured with a flame photometer, and chloride by the Volhard technique. Although this study was primarily a comparative bioassay of two established diuretics against a placebo, no previous direct comparisons of these diuretics could be found in the literature. The diuretic activity of chlorothiazide and quinethazone compared to placebo therapy was confirmed in both humans and rats, the use of controls was illustrated, and a higher mean sodium-potassium ratio for quinethazone than for chlorothiazide was demonstrated.

Animals↗
PubMedDate not supplied

Isolation of lipid and 2-alkylcyclobutanones from irradiated foods by supercritical fluid extraction.

The 2-alkylcyclobutanone method was adopted as a European Standard (EN1785) and MAFF Validated Method (MAFF V37) in 1996 for the detection of irradiated food containing fat. As the method requires a relatively long period (ca 2 days) of time for extraction of the 2-alkylcyclobutanones from a foodstuff, a means was sought to increase the speed at which these irradiation markers could be isolated while at the same time decreasing the amount of organic solvents required. Thus, the technique of supercritical fluid extraction (SFE) was investigated. Results showed that SFE can be used for the rapid extraction (60 min) of lipid from irradiated foods such as chicken, pork, liquid whole egg, ground beef, and from the seeds of irradiated mango and papaya with only 10 mL n-hexane being necessary for collection of the extracted sample. A method was also developed whereby the 2-alkylcyclobutanones can be selectively extracted from irradiated foods without prior extraction of the lipid. The sample extract, in 10 mL n-hexane, is purified through a Florisil SPE cartridge which is washed with 10 mL n-hexane and the 2-alkylcyclobutanones eluted with 10 mL 2% diethyl ether in n-hexane before analysis by gas chromatography/mass spectrometry. 2-Dodecylcyclobutanone and 2-tetradecylcyclobutanone were selectively extracted from irradiated chicken meat, liquid whole egg, ground beef, and mango as well as from beef burgers and baked products containing irradiated ground beef and liquid whole egg, respectively. Using this method, samples can be analyzed for irradiation treatment within 6 h as opposed to the 2-day period required for the EN1785/MAFF V37 validated method.

Animals↗