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1. The metabolism of sulphur mustard, 1,1'-thiobis(2-chloroethane), in vivo was investigated following i.p. administration to rat. 2. Approx. 60% of dose was excreted in the 24 h urine. Many metabolites were present; nine have been isolated by h.p.l.c. and characterized by mass spectrometry. Structural assignments were confirmed by comparison with authentic synthetic standards. 3. Some metabolites result from initial hydrolysis of the sulphur mustard, but the majority are formed by conjugation with glutathione. These are further metabolized to N-acetylcysteine conjugates, or to methylthio/methylysulphinyl derivatives by a pathway probably involving beta-lyase, accompanied by oxidation of the mustard sulphur atom to sulphoxide or sulphone. 4. Thiodiglycol sulphoxide, 1,1'-sulphonylbis[2-S(N-acetylcysteinyl)ethane] and 1,1'-sulphonylbis[2-methylsulphinyl)ethane] or 1-methylsulphinyl-2-[2-(methylthio ethylsulphonyl]ethane were the most prevalent metabolites resulting from the three major pathways. Metabolic pathways for the formation of the excretion products are proposed.

ObjectiveTo determine whether a change in editorial policy, including the implementation of a checklist, has been associated with improved reporting of measures which might reduce the risk of bias.MethodsThe study protocol has been published at doi: 10.1007/s11192-016-1964-8.DesignObservational cohort study.PopulationArticles describing research in the life sciences published in Nature journals, submitted after 1 May 2013.InterventionMandatory completion of a checklist during manuscript revision.Comparators(1) Articles describing research in the life sciences published in Nature journals, submitted before May 2013; and (2) similar articles in other journals matched for date and topic.Primary outcomeThe primary outcome is change in the proportion of Nature articles describing in vivo research published before and after May 2013 reporting the ‘Landis 4’ items (randomisation, blinding, sample size calculation and exclusions). We included 448 Nature Publishing Group (NPG) articles (223 published before May 2013, and 225 after) identified by an individual hired by NPG for this specific task, working to a standard procedure; and an independent investigator used PubMed ‘Related Citations’ to identify 448 non-NPG articles with a similar topic and date of publication from other journals; and then redacted all articles for time-sensitive information and journal name. Redacted articles were assessed by two trained reviewers against a 74-item checklist, with discrepancies resolved by a third.Results394 NPG and 353 matching non-NPG articles described in vivo research. The number of NPG articles meeting all relevant Landis 4 criteria increased from 0/203 prior to May 2013 to 31/181 (16.4%) after (two-sample test for equality of proportions without continuity correction, Χ²=36.2, df=1, p=1.8×10−9). There was no change in the proportion of non-NPG articles meeting all relevant Landis 4 criteria (1/164 before, 1/189 after). There were more substantial improvements in the individual prevalences of reporting of randomisation, blinding, exclusions and sample size calculations for in vivo experiments, and less substantial improvements for in vitro experiments.ConclusionThere was an improvement in the reporting of risks of bias in in vivo research in NPG journals following a change in editorial policy, to a level that to our knowledge has not been previously observed. However, there remain opportunities for further improvement.

The urinary excretion profiles of some metabolites of sulfur mustard were determined by gas chromatography/mass spectrometry after cutaneous application of sulfur mustard in rats. Excretion profiles of the individual metabolites thiodiglycol and thiodiglycol sulfoxide, derived from the hydrolysis of sulfur mustard, were determined in different groups of three rats. Concentrations of thiodiglycol detected increased up to 10 fold after treatment of the urine with hydrochloric acid, presumably because of the excretion of acid-labile esters of thiodiglycol. Free thiodiglycol, free plus esterified thiodiglycol, and thiodiglycol sulfoxide excreted over 8 days accounted for less than 0.3%, 1-1.5%, and 3.4-4.3%, respectively, of the applied dose of sulfur mustard. In a further study, a modified analytical method was applied to determine these hydrolysis products and their acid-labile esters as the single analyte thiodiglycol, after treatment with acidic titanium trichloride. The excretion profile of the combined hydrolysis products was compared with the excretion profile of a different group of metabolites of sulfur mustard derived from the glutathione/beta-lyase pathway. These were also reduced to a common analyte, 1,1'-sulfonylbis-[2-(methylthio)ethane], after similar treatment with titanium trichloride. Urinary excretion of hydrolysis products determined in 4 rats over 8 days accounted for 3.7-13.6% of an applied cutaneous dose of sulfur mustard. Urinary excretion of beta-lyase metabolites accounted for 2.5-5.3% of the applied dose in the same group of rats. The excretion of beta-lyase products showed a much sharper decline than was observed for the hydrolysis products of sulfur mustard.

1. Methods are described for the isolation of radioactively pure thiamine from yeast and its degradation on a small scale to its cyclic components. 2. A degradation of the pyrimidine ring and a thin-layer method for the separation of thiamine, its derivatives and pyrimidine and thiazole residues are described. 3. [(14)C]Formate is more effectively incorporated into the pyrimidine residue than into the thiazole residue, whereas the reverse is true with l-[Me-(14)C]methionine. 4. Experiments with [Me-(14)C,(35)S]methionine demonstrate that methionine provides an intact unit for the biosynthesis of the thiazole ring. 5. [6-(14)C]Orotic acid is insignificantly incorporated into the pyrimidine residue of thiamine. 6. Experiments with [1-(14)C]- and [2-(14)C]-acetate indicate that it is incorporated as a unit into the thiazole residue, but that only C-2 is incorporated into the pyrimidine residue. 7. l-[U-(14)C]Alanine is also effectively incorporated into the thiazole residue. 8. These results are discussed in relation to possible pathways of biosynthesis of the two ring components of the thiamine molecule.