Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (Co-PCBs) were determined in the liver and pectoral muscle of common cormorants (Phalacrocorax carbo) collected from Lake Biwa, Japan. To clarify the toxicokinetic behaviors and potential toxicities of these chemicals, the present study addresses life-stage- and tissue-specific accumulation of the congeners. Total 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) were in the range of 360 to 50,000 pg/g lipid weight in the liver and 310 to 12,000 pg/g lipid weight in the pectoral muscle. Among congeners, for which toxic equivalency factors were assigned, PCB126, 2,3,4,7,8-P5CDF, and 1,2,3,7,8-P5CDD made a greater contribution to total TEQs in the liver. Hepatic concentrations of T4- to H6CDDs, P5- and H6CDFs, and Co-PCBs (except PCB77) significantly increased with growth of cormorants, leading to life-stage-related compositional changes. The concentration ratios of liver to pectoral muscle revealed preferential accumulation of higher chlorinated congeners in hepatic tissue. For most congeners, concentration ratios significantly increased with an increase in hepatic total TEQs, suggesting their concentration-dependent hepatic sequestration. These results imply the presence of hepatic binding protein(s) such as cytochrome P450, inducible by these chemicals, which mayfunction as a binding species different from aryl hydrocarbon receptor. On the basis of these results, we conclude that the toxicokinetic behavior of each congener is life-stage-, tissue-, and concentration-dependent. TEQs in wildlife populations exposed to multiple congeners with varying concentrations should be used with caution for risk assessment, even within a species.

Hand assisted retroperitoneoscopic nephroureterectomy is an effective and safe alternative to open nephroureterectomy for upper urinary tract transitional cell carcinoma.

The present study examines the effects of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (Co-PCBs) on hepatic cytochromes P450 (CYP) in the wild population of common cormorants from Lake Biwa, Japan, and discusses functional roles of CYP1A in terms of correlation analysis between tissue concentrations of individual congeners and expression levels of CYP1A. Levels of alkoxyresorufin (methoxy-, ethoxy-, pentoxy-, and benzyloxyresorufin) O-dealkylase activities and a protein cross-reacted with anti-rat CYP1A1 polyclonal antibodies showed significant positive correlations with total 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) or TEQs for most individual congeners in the liver of cormorants, suggesting induction of CYP1A-like protein by these chemicals. In contrast, TEQs for lower chlorinated congeners, 2,3,7,8-T4CDF and PCB77, showed relatively low correlations with the expression level of CYP1A-like protein. Concentrations of 2,3,7,8-T4CDF and PCB77 normalized to a relatively recalcitrant congener, PCB169, were negatively correlated with the CYP1A-like protein level. These results indicate preferential metabolism of those congeners by CYP1A-like protein that was induced by TEQs. Concentration ratios of liverto pectoral muscle for certain congeners significantly increased with an elevation of the CYP1A-like protein level. Comparing the results in the present study with those of previous studies using rodents treated with certain dioxin-like congeners, these congeners in the liver may be sequestered by CYP1A. Levels of cross-reactive proteins with anti-rat CYP2B1, CYP2C6, and CYP3A2 polyclonal antibodies correlated with neither TEQs nor liver/muscle concentration ratios of congeners. We conclude that the potential for CYP1A induction, and metabolism and sequestration of dioxin-like compounds by CYP1A, may be a critical factor for assessing the ecological risk in wild avian species.