In Vitro Effect of Bile Acids
Herman Autrup, Gary M. Williams in Experimental Colon Carcinogenesis, 2019
Silverman and Andrews52 attempted to reproduce the promoting effect of bile acids on chemical carcinogens administered to the colon of rats using the Ames Salmonella-Mammalian Microsome Mutagenicity test. After testing some 30 bile acids with the various tester strains, with and without a phenobarbital-stimulated 9000 × g postmitochondrial supernatant fraction (S9), the authors found none of the bile acids to be mutagenic. Using suboptimal levels of two model carcinogens, MNNG (N-methyl-N′-nitro-N-nitrosoguanidine) and 2-aminoanthracene, lithocholic acid was found to enhance the mutagenicity of the aromatic amine only. In addition, lithocholic acid derivatives including the glycine and taurine conjugates as well as 3-keto-5β-cholanic acid enhanced the mutagenicity of 2-aminoanthracene when coincubated with the carcinogen. When an Aroclor-induced S9 preparation was used, no enhancement effects were observed. The different mutagen-enhancing activities of the bile acids with various S9 preparations are shown in Figure 2.
Risk Characterization
Ted W. Simon in Environmental Risk Assessment, 2019
The chlorine used to produce toxaphene was produced at a nearby chlor-alkali plant. Both polychlorinated biphenyls and mercury are used in the electrolytic cells needed for the chlor-alkali process. Toxaphene, Aroclor 1268, a high-molecular weight polychlorinated biphenyl (PCB) mixture, and mercury were released during chlorine production and toxaphene manufacture. All three chemicals bioaccumulate in fish, and this example demonstrates the risk assessment of consumption of fish contaminated with these three chemicals. The last number in the Aroclor designation represents the weight percentage of chlorine in the PCB mixture. The most highly chlorinated mixture is Aroclor 1268, with 68% chlorine by weight.
Halogenated hydrocarbons
Bev-Lorraine True, Robert H. Dreisbach in Dreisbach’s HANDBOOK of POISONING, 2001
Chloronaphthalenes, dichloronaphthalenes, polychlorinated naphthalene (Halowax), polybrominated biphenyl (PBB), and polychlorinated biphenyl (PCB, Arochlor) are used as high-temperature dielectrics for electric wires, electric motors, transformers, and other electrical equipment. They are also used as heat-exchange fluids, plasticizers, coatings, fillers, adhesives, and in paints, inks, and duplicating papers. Depending on the amount of chlorination, the melting point for these compounds varies from 80 to 130°C.
Concentration dependence of human and mouse aryl hydrocarbon receptor responsiveness to polychlorinated biphenyl exposures: Implications for aroclor mixtures
Published in Xenobiotica, 2019
Hongxue Shi, Josiah E. Hardesty, Jian Jin, Kimberly Z. Head, K. Cameron Falkner, Matthew C. Cave, Russell Allen Prough
PCBs are polyhalogenated aromatic hydrocarbons and consist of up to 10 chlorine atoms attached to a biphenyl ring. PCBs were manufactured as mixtures (US tradename Aroclor) and sold by the percentage of chlorine in the mix. For example, Aroclor 1254 is 54% chlorine by mass, while Aroclor 1260 is 60% chlorinated. Of the 209 theoretical PCB congeners, approximately 130 were present in commercial PCB mixtures. PCB mixtures were used in a variety of industrial applications, such as insulating agents for electrical transformers. Approximately 1.3 million tons were produced worldwide before PCBs were banned (Ockenden et al., 2003). The primary routes of human PCB exposure are ingestion of contaminated food (Schecter et al., 2003) or breast milk, and inhalation of contaminated air (Ampleman et al., 2015). PCB metabolism varies considerably with low molecular weight PCBs being metabolized at a higher rate than the more heavily chlorinated PCBs. This leads to bioaccumulation patterns in adipose that greatly favor retention of the more highly chlorinated congeners being similar to those present in Aroclor 1260. However, there is an important exception. Aroclor 1260 is not believed to contain significant amounts of DL PCBs (Battelle Memorial Institute, 2012; Wahlang et al., 2014a; Wahlang et al., 2014b).
Impact of selenium status on Aroclor 1254-induced DNA damage in sperm and different tissues of rats
Published in Toxicology Mechanisms and Methods, 2018
Sevtap Aydin, Pinar Erkekoglu, Nurşen Başaran, Belma Kocer-Gumusel
Aroclor 1254, an important PCB congener was commonly used in some countries as a non-flammable heat transfer agent in electric capacitors, power transformers, vacuum pumps and gas-transmission turbines (Shields 2006; Erickson and Kaley 2011). Aroclor 1254 has been shown to increase ROS production in various organs (i.e. liver, brain and spleen) and the toxicity of Aroclor 1254 may be attributable to free radical generation (Banudevi et al. 2006; Aly and Domènech 2009). Aroclor 1254 was shown to significantly reduce renal antioxidant enzyme activities, hepatic and renal glutathione (GSH) levels and increase lipid peroxidation, H2O2 and hydroxyl radical levels in rat liver, kidney and lung (Banudevi et al. 2006). Moreover, studies have also reported that Aroclor 1254 caused changes in antioxidant systems of the ventral prostate, seminal vesicle and testis in rats. These alterations, in turn, disrupted sperm parameters (Venkataraman et al. 2004a; Venkatarama et al. 2004b; Aly et al. 2009).
Sex differences in the association of measures of sexual maturation to common toxicants: Lead, dichloro-diphenyl-trichloroethane (DDT), dichloro-diphenyl-dichloroethylene (DDE), and polychlorinated biphenyls (PCBs)
Published in Annals of Human Biology, 2021
Casey N. West, Lawrence M. Schell, Mia V. Gallo
The problem of comparing results is especially severe in comparing studies of PCBs. Most PCBs were sold under the trade name Aroclor and these were manufactured with different percentages of chlorine (usually indicated by the last two digits of the name, as in Aroclor 1254 which is 54% chlorine by weight). That percentage is achieved by a mixture of different congeners, some highly chlorinated and others much less so. Any studied population will have a mix of PCB congeners in serum depending on which Aroclors it was exposed to. Thus, no two populations have the same combination of PCB congeners. As specific congeners are related to endocrine activity, different effects are to be expected from different combinations of congeners and each study is virtually unique in exposure.
Related Knowledge Centers
- Chloride
- Persistent Organic Pollutant
- Toxicity
- Carcinogen
- Organochlorine Chemistry
- Carbon
- Hydrogen
- Carbonless Copy Paper
- Dioxins & Dioxin-Like Compounds
- Polychlorinated Dibenzodioxins