A reassessment of the nomenclature of polychlorinated biphenyl (PCB) metabolites.

Polychlorinated biphenyls (PCBs) are a widespread class of persistent organic chemicals that accumulate in the environment and humans and are associated with a broad spectrum of health effects. PCB biotransformation has been shown to lead to two classes of PCB metabolites that are present as contaminant residues in the tissues of selected biota: hydroxylated (HO) and methyl sulfone (MeSO2) PCBs. Although these two types of metabolites are related structures, different rules for abbreviation of both classes have emerged. It is important that a standardized nomenclature for the notation of PCB metabolites be universally agreed upon. We suggest that the full chemical name of the PCB metabolite and a shorthand notation should be adopted using the International Union of Pure and Applied Chemistry's chemical name/original Ballschmiter and Zell number of the parent congener, followed by the assignment of the phenyl ring position number of the MeSO2- or HO-substituent. This nomenclature provides a clear, unequivocal set of rules in naming and abbreviating the PCB metabolite structure. Furthermore, this unified PCB metabolite nomenclature approach can be extended to the naming and abbreviation of potential metabolites of structurally analogous contaminants such as HO-polybrominated biphenyls and HO-polybrominated diphenyl ethers

Modeling the public health impact of different meningococcal vaccination strategies with 4CMenB and MenACWY versus the current toddler MenACWY National Immunization Program in Chile

Invasive meningococcal disease (IMD) is an uncommon yet unpredictable, severe, and life-threatening disease with the highest burden in young children. In Chile, most IMD is caused by meningococcal serogroup B (MenB) and W (MenW) infection. In response to a MenW outbreak in 2012, a toddler vaccination program was implemented using quadrivalent meningococcal conjugate vaccine against serogroups A, C, W and Y (MenACWY). The vaccine program, however, does not protect infants or other unvaccinated age groups and does not protect against MenB IMD. Since 2017, MenB IMD cases are becoming increasingly prevalent. Using a dynamic transmission model adapted for Chile, this analysis assessed the public health impact (reduction in IMD cases, long-term sequelae, deaths, and quality-adjusted life-years) of six alternative vaccination strategies using MenACWY and/or the four-component MenB (4CMenB) vaccine in infants, toddlers, and/or adolescents compared to the National Immunization Program (NIP) implemented in 2014. Strategies that added infant 4CMenB to MenACWY in toddlers or adolescents would prevent more IMD than the current NIP, observed within the first 5 years of the program. Replacing the NIP by an adolescent MenACWY strategy would prevent more IMD in the longer term, once herd immunity is established to protect unvaccinated infants or older age groups. The strategy that maximized reduction of IMD cases and associated sequelae in all age groups with immediate plus long-term benefits included infant 4CMenB and MenACWY in both toddlers and adolescents. This analysis can help policymakers determine the best strategy to control IMD in Chile and improve public health. A set of audio slides linked to this manuscript can be found at https://doi.org/10.6084/m9.figshare.16837543

Uptake and tissue-specific distribution of selected polychlorinated biphenyls in developing chicken embryos

Fertilized chicken eggs were injected with high doses of individual polychlorinated biphenyl (PCB) congeners (0.5 microg of PCB 77, 9.8 microg of PCB 153, or 10.9 microg of PCB 180) before incubation to investigate the structure-specific uptake of these compounds by the embryo and their accumulation in brain and liver tissue. In accordance with earlier publications, a gradual uptake and accumulation of these compounds was observed during the last week of embryonic development. The PCB uptake and distribution to the specific tissues did not appear to be structure dependent. Wet-weight liver PCB concentrations (18, 266, and 278 ng/g at hatching for PCB 77, PCB 153, and PCB 180, respectively) were consistently two- to fourfold higher than carcass levels (7 ng/g of PCB 77, 117 ng/g of PCB 153, and 81 ng/g of PCB 180 at hatching). Whereas liver and carcass concentrations increased exponentially between day 13 of incubation and hatching, PCB levels in brain tissue remained unaltered (range, 0.6-1.0 ng/g of PCB 77 and 8-12 ng/g of PCB 153 and PCB 180 throughout the last week of incubation). Lipid analysis of the organs suggested that the lipid composition of brain may be an important factor explaining the low PCB accumulation in this tissue.status: publishe