Biomedical subjects

E BOYLAND

Publications and source records attributed to E BOYLAND.

At least 19 recordsLinked to original sources

PubMed1965

CHEMOTHERAPY OF TUBERCULOSIS.

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Carcinogens↗

PubMed1965

AN ENZYME CATALYSING THE CONJUGATION OF EPOXIDES WITH GLUTATHIONE.

1. Liver supernatant preparations from rats and ferrets catalyse the conjugation of some epoxides with glutathione. The enzyme involved might be called ;glutathione S-epoxidetransferase', as it is different from glutathione S-aryltransferase, the enzyme catalysing the conjugation of 1,2-dichloro-4-nitrobenzene, 4-nitro-pyridine N-oxide and other cyclic compounds with glutathione and from the enzyme catalysing the conjugation of iodomethane and glutathione. 2. The enzyme does not catalyse the reaction with cysteine. It is not inactivated by dialysis but is unstable at pH 5.0. 3. The role of the enzyme in metabolism of foreign compounds is discussed.

Carnivora↗

PubMed1965

THE MATABOLISM OF URETHANE AND RELATED COMPOUNDS.

1. Urethane is metabolized in the rat, rabbit and man by a process of N-hydroxylation. This occurs to a smaller extent when methyl, n-propyl and n-butyl carbamates are administered to the rat and rabbit. 2. Other metabolites which have been detected in urine of animals dosed with urethane and N-hydroxyurethane are ethylmercapturic acid, ethylmercapturic acid sulphoxide and N-acetyl-S-carbethoxycysteine. 3. Substances which appear to be S-ethylglutathione and S-ethylglutathione sulphoxide have been detected in the bile of rats dosed with urethane or N-hydroxyurethane. 4. Methyl, ethyl, n-propyl and n-butyl N-hydroxycarbamates are excreted unchanged in the urine of rats dosed with these compounds to extents depending on the dose administered. 5. Animals dosed with methyl, ethyl, n-propyl or n-butyl carbamate or the corresponding N-hydroxycarbamate excrete the corresponding carbamate and N-hydroxycarbamate in the urine. 6. Methyl, n-propyl and n-butyl carbamates and N-hydroxycarbamates are excreted more slowly than are urethane and N-hydroxyurethane. 7. The probable role of N-hydroxyurethane and the processes of alkylation and carbethoxylation, and of hydroxylamine, nitroxyl and hyponitrous acid in carcinogenesis and chemotherapy with urethane, have been discussed.

Animals↗

PubMed1965

METABOLISM OF POLYCYCLIC COMPOUNDS. THE METABOLISM OF 7,12-DIMETHYLBENZ(ALPHA)ANTHRACENE BY RAT-LIVER HOMOGENATES.

1. The main products of the metabolism of 7,12-dimethylbenz[a]anthracene by rat-liver homogenates are the isomeric monohydroxymethyl derivatives. The syntheses of these compounds are described. 2. Two phenolic products and two dihydrodihydroxy compounds were formed, but none of these appeared to have been formed by hydroxylation at the ;K region'. There was little evidence for the formation of a glutathione conjugate of the hydrocarbon. 3. The monohydroxymethyl derivatives are products of the hydroxylation of the hydrocarbon in the ascorbic acid-Fe(2+)-oxygen model hydroxylating system.

Anthracenes↗

PubMed1965

METABOLISM OF POLYCYCLIC COMPOUNDS. THE METABOLISM OF 9,10-EPOXY-9,10-DIHYDROPHENANTHRENE IN RATS.

1. 9,10-Epoxy-9,10-dihydrophenanthrene is converted by rats into trans-9,10-dihydro-9,10-dihydroxyphenanthrene and its conjugates and into N-acetyl-S-(9,10-dihydro-9-hydroxy-10-phenanthryl)-l- cysteine. Small amounts of 9-phenanthryl sulphate and glucosiduronate are also formed, together with 9-hydroxy-10-phenanthryl sulphate. 2. The epoxide readily rearranges to 9-hydroxyphenanthrene and reacts with water to give the dihydrodihydroxy compound and with N-acetylcysteine to give the mercapturic acid. One of the diastereoisomeric forms of the methyl ester of the mercapturic acid is identical with the ester of the mercapturic acid excreted by rats dosed with the epoxide or by rats and rabbits dosed with phenanthrene. 3. A rat-liver homogenate converts the epoxide into trans-9,10-dihydrodihydroxyphenanthrene and S-(9,10-dihydro-9-hydroxy-10-phenanthryl)glutathione. The latter compound was not formed when boiled rat-liver homogenate was used, but was formed chemically from the epoxide and glutathione under more vigorous conditions. 4. The results provide further indications that the metabolism of aromatic hydrocarbons involves the intermediary formation of epoxides.

Acetylcysteine↗

PubMed1965