Effects on bone tissue in ewes (<i>Ovies aries</i>) and their foetuses exposed to PCB 118 and PCB 153

The aim of the present study was to investigate whether low levels of mono-ortho PCB 118 and di-ortho PCB 153, affect bone composition and strength in ewes (Dala breed) and their foetuses following exposure starting at conception and ending a week before expected delivery. In male foetuses, trabecular bone mineral content at the metaphysis was almost 30% lower in the PCB 118 (49mug/kg body wt/day) group compared to the control group (corn oil) (ANCOVA, P&lt;0.05). In female foetuses of the PCB 153 (98mug/kg body wt/day) group trabecular cross-sectional area at the metaphysis was 19% smaller than in the controls (ANCOVA, P&lt;0.05). At the diaphysis a smaller marrow cavity area (up to 24% reduction) was observed in female and male foetuses exposed to PCB 153 compared with controls (ANCOVA, P&lt;0.05). There were also significant differences at the mid diaphyseal measure point between the PCB 153 and the control group females (ANCOVA, P&lt;0.05). Cortical and total bone mineral density, cortical thickness were significantly higher, endosteal circumference shorter and marrow cavity significantly smaller in the PCB 153 group (ANCOVA, P&lt;0.05). In conclusion there were gender dependent effects on bone tissue and cortical bone was more affected than trabecular bone.</p

Polychlorinated biphenyls and their hydroxylated metabolites in placenta from Madrid mothers

Introduction Concentrations and congener profiles of polychlorinated biphenyls (PCBs) and their hydroxylated metabolites (OH-PCBs) in placenta samples from a Madrid population (Spain) are reported. Structure dependent retentions of OH-PCBs are known to occur in both humans and wildlife, making it of interest to assess placental transfer of both parent compounds and their metabolites to the developing foetus.Results The Sigma PCB concentrations found in placenta samples were in the range 943-4,331 pg/g fresh weight (f.w.), and their hydroxylated metabolites showed a 20-time lower concentration level (53-261 pg/g f.w.). The PCB profiles were surprisingly dominated by CB-52 and CB-101 accounting for more than 44% of the total PCB concentration. This is indicating a source of exposure that is not yet identified. The OH-PCB profiles were dominated by 4-OH-CB187 and 4-OH-CB146, representing &gt;50% of the Sigma OH-PCB concentration of the placenta samples. Statistical analysis of the data revealed strong correlations between the PCB congeners, among some OH-PCBs, and between OH-PCB metabolites with a meta- and para- substitution pattern. Both PCB and OH-PCB concentrations presented homogeneous distribution, what allowed the establishment of a partial least squares model that correlated the concentrations of OH-PCB with those of PCBs in placenta samples. In addition, causal correlations were observed between the concentrations of OH-PCBs and those of their corresponding PCB precursors.</p