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Biomedical subjects

M Toyoda

Publications and source records attributed to M Toyoda.

At least 253 records · Page 14Linked to original sources
PubMed1979

Gas-liquid chromatographic determination of thiourea in citrus peels.

A gas-liquid chromatographic (GLC) method was developed for the detection and determination of thiourea in citrus peels. After the peel is extracted with ethyl ether, the ether extract is adsorbed on sodium sulfate together with water. Thiourea is recoverd from both the sodium sulfate and the peel residue with ethyl acetate-acetone(2+1). The extracted mixture is cleaned on an alumina column, the eluate is concentrated under vacuum, and thiourea is extracted from the concentrate with sodium carbonate solution. GLC was carried out on the prepared benzoyl derivative of thiourea. The average recoveries of thiourea from lemon peel were 85.3, 93.1, and 97.6% at the fortification levels of 1, 10, and 100 ppm, respectively. The detection limit was low as 0.08 ppm.

Chromatography, Gas↗
PubMed1978

Chemical control of cerebral circulation. Modification by a new vasodilator (YC-93).

This study was undertaken to investigate influences of a new vasodilator, YC-93, a derivative of 1,4-dihydropyridine, on cerebral circulation and cerebrovascular CO2 reactivity. Cerebrocortical PO2, cerebrocortical PCO2, cerebrocortical blood flow and arterial blood pressure were continuously recorded by means of a PO2 electrode, a PCO2 electrode and a plate-type crossed thermocouple flowmeter placed on an exposed pial surface of the cat brain. The changes in each parameter induced by YC-93 were compared with those induced by papaverine hydrochloride. The effects of 5% CO2 inhalation were compared before and after the intravenous injection of YC-93. YC-93 (0.01 mg/kg) showed a more marked and longer-lasting hypotensive effect that papaverine (1 mg/kg) and yet produced a significant increase in cerebrocortical PO2. After the administration of YC-93, the degree of the increase in cerebrocortical PO2 during 5% CO2 inhalation was reduced significantly in comparison with that before the administration. The above data indicates that YC-93 has a vasodilating effect on cerebral blood vessels and that the drug causes a decrease in cerebrovascular CO2 reactivity.

Animals↗
PubMed1978

Gas-liquid chromatographic determination of nitrate and nitrite in cheese, ham, fish sausage, cod roes, and salmon roes.

The 2,4-xylenol method was modified and a gas-liquid chromatographic (GLC) method was developed for nitrate and nitrite determinations in several foods. Either a flame ionization (FID) or an electron capture detector (ECD) can be used. Proteins and fats are removed from warm alkaline water with zinc sulfate and filtered. The filtrate is evaporated to dryness, redissolved in water, and reacted with 2,4-xylenol in the presence of sulfuric acid to form 6-nitro-2,4-xylenol. Interfering chlorides are precipitated with silver sulfate and the nitrosylenol is extracted with hexane, concentrated, and injected. Nitrite in the filtrate is distilled at pH 5, collected in alkaline solution, and dried. The residue is oxidized to nitrate with permanganate in the presence of sulfuric acid, and then chromatographed in the same manner as nitrate. Recoveries from several foods were 83--100% for nitrate and 80--100% for nitrite. The limit of sensitivity was 0.1 ppm for both residues.

Cheese↗