Clinical Trial of Methyl Cysteine Hydrochloride in Chronic Bronchitis

Palmer, K.N.V.; Geake, M. R.; Brass, W.

doi:10.1136/bmj.1.5274.280

Cited by 5 publications

(1 citation statement)

References 4 publications

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“…, 1999) and in several other vegetables. It has (not only recently) aroused an increasing interest as a protective agent against oxidative stress in several different pathological states, including chronic bronchitis (Palmer, 1962) and in experimental models of human disease, encompassing murine MPTP‐induced (Chen et al. , 2007) and transgenic Drosophila (Wassef et al.…”

Section: Introductionmentioning

confidence: 99%

Measurement of S‐methylcysteine and S‐methyl‐mercapturic acid in human urine by alkyl‐chloroformate extractive derivatization and isotope‐dilution gas chromatography–mass spectrometry

Rubino

Pitton

Fabio

et al. 2011

Biomedical Chromatography

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S-methylcysteine (SMC) is a minor amino acid naturally excreted in human urine, a protective agent against oxidative stress and a biotransformation product of the fumigant biocide methyl bromide and of nicotine. A metabolic source of SMC is catabolism of the repair catalytic protein MGMT (EC 2.1.1.37), which specifically removes the methyl group from the modified DNA nucleotide O-6-methyl-guanine to revert the normal GC base pairing. To assess the value of SMC and of S-methylmercapturic acid (SMMA) as candidate biomarkers of proliferative phenomena, a sensitive analytical method by GC-MS was applied in a pilot study of healthy subjects to assess their urinary elimination and the intra- and inter-individual variability. Extractive alkylation with butylchloroformate-n-butanol-pyridine (Husek technique) was employed for sample derivatization and isotope dilution GC-MS with S-[CD(3) ]-SMC and -SMMA was applied for specific and sensitive detection. To resolve the target analytes from the main coeluting interferents in the derivatized urine extract a medium-polarity stationary phase was employed. SMMA was not detected in the morning urine of three healthy fertile-age women followed for one month above the minimum detectable level of approx. 500 µg/L while SMC concentrations were in the 0.02-0.7 µg/mL range (n = 61) with large inter-day and inter-individual variations. In a young healthy male urine samples taken throughout a few days yielded concentrations in the same 90-810 µg/L range (n = 11). These preliminary results points at SMC as a candidate biomarker for the study of methylation turnover in several biochemical processes.

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Section: Introductionmentioning

confidence: 99%