Breast milk samples, randomly collected from 32 Kuwaiti donors were analysed for chlorinated pesticides. DDE residues ranged from 127 to 3333 micrograms/kg, averaging, 833 micrograms/kg, expressed on a fat weight basis. DDT levels ranged from 0.6 to 67 micrograms/kg fat and averaged 12.4 micrograms/kg, fat. High DDE/DDT ratios were found, which indicated that the exposure to DDT, in most cases, happened quite some time ago. In addition many of the samples also contained isomers of HCH, heptachlor-epoxide, aldrin, dieldrin and endrin. Residue levels of non-DDT pesticides were generally low. Overall levels of DDT-pesticides in Kuwaiti milk samples were lower than levels reported from other Middle Eastern countries, although methodologies may not be directly comparable.
Aims: This study describes the transformation of cholic acid to hydroxylated cholic acid metabolites that could not be easily synthesized. Study Design: The transformation was catalyzed by thermophilic Geobacillus stearothermophilus comb. nov., isolated from oil contaminated soil in Kuwait. Cholic acid, as the sole source of carbon, was added to G. stearothermophilus cells in phosphate buffer pH 7 and shaken at 65ºC for 5 days. Methodology: The cholic acid transformation products were extracted with ethyl acetate, purified on preparative TLC plates and their molecular structures were established from their spectral data. Results: The bacterium could selectively oxidize hydroxyl-groups at C3 and C7 while leaving the C12-hydroxyl-group unoxidized, in cholic acid. Five commonly found metabolites of cholic acid and a novel transformation product, 16α-hydroxycholic acid, were identified.
Conclusion:Our results indicate that G. stearothermophilus can hydroxylate/oxidize a steroid nucleus at various ring positions, and has a unique ability for hydroxylation at C16α in cholic acid.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.