4 4 | Chulalongkorn University (original) (raw)
Papers by 4 4
PLOS Biology, 2006
Open access (OA) to the research literature has the potential to accelerate recognition and disse... more Open access (OA) to the research literature has the potential to accelerate recognition and dissemination of research findings, but its actual effects are controversial. This was a longitudinal bibliometric analysis of a cohort of OA and non-OA
Environmental Science & Technology, 1987
Numerous reports have illustrated the versatility of polychlorinated biphenyls (PCBs) and related... more Numerous reports have illustrated the versatility of polychlorinated biphenyls (PCBs) and related halogenated aromatics as inducers of drug-metabolizing enzymes and the activity of individual compounds are remarkably dependent on structure. The most active PCB congeners,, are substituted at both para and at two or more meta positions. The four coplanar PCBs resembled 3-methylcholanthrene (3-MC) and 2, in their mode of induction of the hepatic drug-metabolizing enzymes. These compounds induced rat hepatic microsomal benzo(a)pyrene hydroxylase (aryl hydrocarbon hydroxylase, AHH) and cytochromes P-450a, P-450c and P-450d. 3,4,4',5-Tetrachlorobiphenyl, the least active coplanar PCB, also induced dimethylaminoantipyrine N-demethylase and cytochromes P-450b + e and resembled Aroclor 1254 as an inducer of the mixed-function oxidase system. Like Aroclor 1254, all the mono-orthoand at least eight di-ortho-chloro analogs of the coplanar PCBs exhibited a "mixed-type" induction pattern and induced microsomal AHH, dimethylaminoantipyrine NM-demethylase and cytochromes P-450a-P-450e. Quantative structure-activity relationships (QSARs) within this series of PCBs were determined by comparing their AHH induction potencies (EC.4) in rat hepatoma H-4-II-E cells and their binding affinities (ED50) for the 2,3,7,8-TCDD cytosolic receptor protein. The results showed that there was an excellent correlation between AHH induction potencies and receptor binding avidities of these compounds and the order of activity was coplanar PCBs (3,3',4,4'-tetra-, 3,3',4,4',5-penta-and 3,3',4,4',5,5'-hexachlorobiphenyls) > 3,4,4',5-tetrachlorobiphenylmono-ortho coplanar PCBs > di-ortho coplanar PCBs. It was also apparent that the relative toxicities of this group of PCBs paralleled their biological potencies.
PLOS Biology, 2006
Open access (OA) to the research literature has the potential to accelerate recognition and disse... more Open access (OA) to the research literature has the potential to accelerate recognition and dissemination of research findings, but its actual effects are controversial. This was a longitudinal bibliometric analysis of a cohort of OA and non-OA
Environmental Science & Technology, 1987
Numerous reports have illustrated the versatility of polychlorinated biphenyls (PCBs) and related... more Numerous reports have illustrated the versatility of polychlorinated biphenyls (PCBs) and related halogenated aromatics as inducers of drug-metabolizing enzymes and the activity of individual compounds are remarkably dependent on structure. The most active PCB congeners,, are substituted at both para and at two or more meta positions. The four coplanar PCBs resembled 3-methylcholanthrene (3-MC) and 2, in their mode of induction of the hepatic drug-metabolizing enzymes. These compounds induced rat hepatic microsomal benzo(a)pyrene hydroxylase (aryl hydrocarbon hydroxylase, AHH) and cytochromes P-450a, P-450c and P-450d. 3,4,4',5-Tetrachlorobiphenyl, the least active coplanar PCB, also induced dimethylaminoantipyrine N-demethylase and cytochromes P-450b + e and resembled Aroclor 1254 as an inducer of the mixed-function oxidase system. Like Aroclor 1254, all the mono-orthoand at least eight di-ortho-chloro analogs of the coplanar PCBs exhibited a "mixed-type" induction pattern and induced microsomal AHH, dimethylaminoantipyrine NM-demethylase and cytochromes P-450a-P-450e. Quantative structure-activity relationships (QSARs) within this series of PCBs were determined by comparing their AHH induction potencies (EC.4) in rat hepatoma H-4-II-E cells and their binding affinities (ED50) for the 2,3,7,8-TCDD cytosolic receptor protein. The results showed that there was an excellent correlation between AHH induction potencies and receptor binding avidities of these compounds and the order of activity was coplanar PCBs (3,3',4,4'-tetra-, 3,3',4,4',5-penta-and 3,3',4,4',5,5'-hexachlorobiphenyls) > 3,4,4',5-tetrachlorobiphenylmono-ortho coplanar PCBs > di-ortho coplanar PCBs. It was also apparent that the relative toxicities of this group of PCBs paralleled their biological potencies.