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Biomedical subjects

T A Baillie

Publications and source records attributed to T A Baillie.

5 recordsLinked to original sources

The identification of 5beta,7alpha-dihydroxy-11-oxotetranor-prostane-1,16-dioic acid as a urinary metabolite of prostaglandin F2alpha in the rat.

5beta,7alpha-Dihydroxy-11-oxotetranor-prostane-1,16-dioic acid has been identified by gas chromatography-mass spectrometry as a urinary metabolite of [9beta-3H]prostaglandin F2alpha in the rat. This tetranor prostaglandin F derivative, which is the 5beta epimer of the major urinary metabolite of prostaglandin F2alpha, accounted for at least 2% of the total dose. Absence from the metabolite of tritium label at the C-5 position indicated the existence of a minor, previously unknown metabolic pathway by which prostaglandin Falpha derivatives may be converted by oxido-reduction into prostaglandins of Fbeta stereochemistry.

Animals

The analysis of terbutaline in biological fluids by gas chromatography electron impace mass spectrometry.

A highly sensitive and specific assay is described for the bronchodilator drug terbutaline in human plasma and urine, based on single ion monitoring gas chromatography mass spectrometry and employing a homologue of the drug as internal standard. Recovery of terbutaline and internal standard into ethyl acetate is effected at pH 9.8, while back-extraction into dilute acid serves to purify the initial extract. Following preparation of O-TMS, N-TFA derivatives, the drug and its homologue are detected by selected ion monitoring of their common base ion at m/e 355. The limit of detection of terbutaline by this procedure is 0.3 ng ml-1 from a 4 ml sample of plasma.

Chromatography, Gas

A comparison of t-butyldimethylsilyl and trimethylsilyl ether derivatives for the characterization of urinary metabolites of prostaglandin F2alpha by gas chromatography mass spectrometry.

t-Butyldimethylsilyl and trimethylsilyl ether derivatives of a series of methylated prostaglandin F2alpha metabolites have been compared with respect to their gas chromatographic and mass spectrometric properties. The t-butyldimethylsilyl derivatives had considerably higher retention indices (approximately 2.2 C units per silyl group) than their trimethylsilyl ether counterparts when analysed on the (non-polar) OV-1 stationary phase. Electron impact induced fragmentation patterns were strongly dependent upon the type of silyl ether employed and on the nature of the prostaglandin omega sidechain; the mass spectra of pairs of t-butyldimethylsilyl and trimethylsilyl ether derivatives were found to differ appreciably in several respects and to afford complementatary structural information.

Animals

A non-enzymic procdure for the quantitative analysis of (3-methoxy-4-sulphoxyphenyl)ethylene glycol(MHPG sulphate) in human urine using stable isotope dilution and gas chromatography-mass spectrometry.

A method is described for the quantitative analysis of (3-methoxy-4-sulphoxyphenyl)-ethylene glycol (MHPG sulphate) in human urine, based on selected ion monitoring gas chromatography--mass spectrometry and using a specifically deuterium-labelled analogue of MHPG sulphate as internal standard. The procedure involves extraction of the urine sample on Amberlite XAD-2, followed by isolation of MHPG sulphate by column chromatography on Sephadex LH-20. Cleavage of the sulphate conjugate and formation of the MHPG tris(trifluoroacetate) derivative are carried out in a one-step reaction, without recourse to enzymic hydrolysis.

Chromatography, Gas