Global metabolite profiling of human colorectal cancer xenografts in mice using HPLC-MS/MS.

Reversed-phase gradient LC-MS was used to perform untargeted metabonomic analysis on extracts of human colorectal cancer (CRC) cell lines (COLO 205, HT-29, HCT 116 and SW620) subcutaneously implanted into age-matched athymic nude male mice to study small molecule metabolic profiles and examine possible correlations with human cancer biopsies. Following high mass accuracy data analysis using MS and MS/MS, metabolites were identified by searching against major metabolite databases including METLIN, MASSBANK, The Human Metabolome Database, PubChem, Biospider, LipidMaps and KEGG. HT-29 and COLO 205 tumor xenografts showed a distribution of metabolites that differed from SW620 and HCT 116 xenografts (predominantly on the basis of relative differences in the amounts of amino acids and lipids detected).

Methodological considerations in the development of HPLC-MS methods for the analysis of rodent plasma for metabonomic studies.

A study of the factors involved in obtaining valid global metabolite profiles from the HPLC-MS of rat or mouse plasma for the purposes of metabonomic analysis has been undertaken. Plasma proteins were precipitated with three volumes of either methanol or acetonitrile. Chromatographic separations were performed on a C18-bonded stationary phase using 3.

UPLC-MS-based analysis of human plasma for metabonomics using solvent precipitation or solid phase extraction.

A study of the factors involved in obtaining valid global metabolite profiles from the LC-MS of human plasma for the purposes of metabonomic analysis has been undertaken. Plasma proteins were either precipitated with 3 vol of organic solvent (methanol or acetonitrile) or subjected to solid phase extraction (SPE) on a C18-bonded phase. For chromatography, a reversed-phase gradient system, based on acidified water/methanol, was used.

Frequency of biocide resistance genes, antibiotic resistance and the effect of chlorhexidine exposure on clinical methicillin-resistant Staphylococcus aureus isolates.

Objectives: To detect genes conferring resistance to biguanides, quaternary ammonium compounds, beta-lactams and fluoroquinolones in clinical methicillin-resistant Staphylococcus aureus (MRSA) and to demonstrate whether reduced susceptibility is spread clonally and if the presence of any of the detected genes links to a specific epidemic MRSA. Finally, to identify if exposure to chlorhexidine may cause reduced susceptibility to antibiotics and chlorhexidine.

Methods: In total, 120 clinical MRSA isolates were isolated.