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Biomedical subjects

I MacDonald

Publications and source records attributed to I MacDonald.

At least 55 records · Page 3Linked to original sources
PubMed1980

Comparison of personal pollution monitoring techniques for use in the operating room.

Three personal pollution monitors (adsorption tubes, diffusion dosimeters and evacuated bottles) have been tested, in routinely used operating rooms and under controlled laboratory conditions, for their accuracy and reproducibility relative to one another and to measurements by infra-red spectroscopy. All the techniques provide time-weighted average measurements of pollutant concentrations. Tubes and dosimeters measure halothane with greater accuracy than that required by N.I.O.S.H. regulations, but neither technique can measure inorganic pollutants such as nitrous oxide. The prototype evacuated bottles tested are unsatisfactory at their present stage of development for the measurement of both halothane and nitrous oxide concentrations. We believe that, at the present time, surveys of operating room pollution can best be carried out using adsorption tubes of diffusion dosimeters for personal halothane concentrations and a portable infra-red spectrometer for measurement of background nitrous oxide concentrations.

Adsorption↗
PubMed1979

Survey of operating room pollution within an N.H.S. district.

Pollution by waste anaesthetic gases was measured in all operating departments in a typical N.H.S. district. Methods were chosen to provide time-weighted average levels over the period of each operating session. The results showed that air-conditioning alone could not guarantee pollution levels below suggested maximum levels and that to meet those requirements air-conditioning plus scavenging was necessary. Background pollution levels were found to be representative of the personal exposure of nursing staff but approximated to only one third of the anaesthetists' personal exposure. Dental clinics presented special problems, namely the very high levels of pollution to which the dentist and his assistants were exposed.

Air Conditioning↗
PubMed1979

Effect of glycerol on triglyceride metabolism in the rat.

Lipid metabolic studies were carried out on the male Wistar rats fed on glycerol-rich diet in order to elucidate the mechanism of glycerol-induced hypertriglyceridemia. No difference was found between the glycerol fed rats and the control rats in the rate of triglyceride secretion from the liver measured by the Triton WR-1339 method as well as in the rate of incorporation of labeled glycerol into liver triglyceride. The facts that the half-life of the intravenously injected Intralipid in the blood was significantly delayed in the glycerol fed rats and that the lipoprotein lipase activity released from epididymal adipose tissue of the glycerol fed rats was markedly decreased to 19% of that of the control rats seem to account for the serum triglyceride elevation induced by the glycerol feeding.

Adipose Tissue↗
PubMed1977

Gas chromatographic determination of Ostwald solubility coefficients for cyclopropane, halothane and trichloroethene (trichloroethylene).

Gas chromatographic methods using solvent extraction for the analysis of cyclopropane and and trichloroethene (trichloroethylene) are described and evaluated; cyclopropane was extracted into carbon tetrachloride and trichloroethene into carbon disulphide, using chloroform and toluene respectively as the internal standards. Ostwald solubility coefficients were measured for cyclopropane, halothane and trichloroethene in Krebs solution: at 310 K the respective values +/- SEM of the Ostwald coefficients are 0.181 +/- 0.009, 0.78 +/- 0.02 and 1.54 +/- 0.02; over the temperature range 295-310 K the respective temperature coefficients of solubility are -2.27, -4.18 and -3.81 in units of per cent/K at 310 K.

Chromatography, Gas↗
PubMed1976

Prazosin and hydrallazine in the treatment of hypertension.

1. Two vasodilators, prazosin and hydrallazine, have been compared in three double-blind cross-over studies designed to test their effect when used in combination with a beta-adrenoceptor-blocking agent and a thiazide. 2. Single doses of 3 mg of prazosin or 75 mg of hydrallazine were administered to patients whose blood pressures remained uncontrolled on a thiazide and a beta-adrenoceptor-blocking agent. Both agents produced significant falls in systolic and diastolic blood pressure apparent at 1 h. The effects of prazosin persisted for 6-7 h and those of hydrallazine for 4-6 h. Tachycardia was more marked and more prolonged after hydrallazine and continued after the blood pressure had risen to base-line levels or above. 3. In 6 week and 12 week double-blind cross-over studies, mean falls in blood pressure were similar with prazosin and hydrallazine. Similar falls in the supine diastolic blood pressure were achieved with 1 mg of prazosin and 20 mg of hyrallazine, but for a given fall in supine diastolic blood pressure, prazosin produced a significantly lower standing diastolic blood pressure. 4. Severe side effects were more pronounced after hydrallazine, which necessitated withdrawal of seven patients, whereas only one patient on prazosin withdrew from the trial because of side effects.

Heart Rate↗
PubMed1976

Halothane 0.2-4% analysis by gas chromatography.

The katharometer detector is better suited to the analysis of gaseous halothane (0.2-4%) than is the flame ionization detector, since the peak heights are directly proportional to concentration, and are more reproducible.

Chromatography, Gas↗