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Oestrogenic activity and nonylphenol
Informal :ion
Polnoks R - developmental toxicity Polnoks R (poly-1,2dihydro_2,2&rimethylquinoline), an antioxidant used in the processing of elastomers, was given by stomach tube to female rats on days 6-15 of pregnancy. It was embryo- and foetotoxic and produced birth defects at the top and maternally toxic dose of 670 mg/kg body weight/ day. Foetal and maternal toxicity were also seen at 340 mg/kg body weight/day. There was some indication of a foetotox;c effect at the lowest tested dose of 170 mg/kg body weight/day (Sitarek K. et al., Teratogenesis, Carcinogenesis and Mutagenesis 1996, 16, 75).
Nervous system effects from low levels of styrene Subtle central and peripheral nervous system changes were detected in 41 workers in Taiwanese plants producing fibreglass-reinforced plastics. The mean daily styrene exposure was 22 ppm (range 0-181 ppm); the (8-hr) exposure limit in the UK is 100 ppm (Tsai S.-Y. and Chen J.-D., Neurotoxicology and Temtology 1996, 18,463).
Thiuram mix sensitization - elicitation threshold A Danish investigation .indicates that synthetic sweat may be a more rel.evant medium for patch-testing for thiuram sensitization than is petrolatum. Even with the more appropriate vehicle, an acceptable threshold for leachable thiurams in rubber gloves was not identified from the patch-testing of 19 patients, since sensitization reactions were elicited at the lowest test concentration of 0.005% thiuram mix. The acceptable threshold was considered likely to be “substantially less than 0.001 mg/cm2” (Knudsen B.B. and Menne T., Contact Dermatitis 1996,34, 410). Prenatal PCB exposure and IQ A battery of IQ and achievement tests was conducted in 212 ll-yr-old children, 167 of whom were born to women wlho had eaten PCB-contaminated fish from Lake Michigan and 45 of whom were born to women who had not. The most highly exposed group of children were three times as likely to have low IQ scores (P< 0.001) and twice as likely to be at least 2 yr behind in reading comprehension (P-0.03). The investigators concluded that prenatal exposure to PCBs “in concentrations slightly higher than those in the general population can have a long-term impact on intellectual function” (Jacobson J.L. and Jacobson
Section
1197
S.W., New England Journal ofMedicine 1996,335, 783).
Mutagenic catalyst in dentine bonding material Tri-n-butyl borane oxide, a catalyst of a dentine bonding agent, was mutagenic in Salmonella typhimurium (Ames test) in the absente of metabolic activation. The mutagenic potential was detectable when the catalyst was dissolved in saline, but not when dimethyl sulfoxide was the solvent (Schweikl H. et al, Biomaterials 1996, 17, 1451).
Photocopier toner dust A 3%yr-old man who worked in a newspaper agency developed a disease of the lymph system (mediastinal lymphadenopathy) and lung damage (granulomatous pneumonitis) associated with his exposure to photocopier toner dust. The link was based on the detection of copper in both lung biopsies and the toner. His symptoms, including dry cough and breathing difficulty, began after about 6 months’ employment at the agency (Armbruster C. et al., Lancet 1996,348, 690).
Oestrogenic activity and nonylphenol Nonylphenol, which is present in the environment, including drinking water, has been shown to be oestrogenic (causing increases in uterine weight, uterine protein and DNA contents, and uterine peroxidase activity) when given as a single intraperitoneal injection at 1 mg/animal (about 20 mg/kg body weight) to immature rats. The effects mimicked those seen with oestradiol (tested at doses of about 0.05 mg/kg body weight). The investigators reported that “nonylphenol was ineffective when used at a pg range”, indicating that it is 1000 to 2OOO-fold less potent than estradiol (Lee P.-C. and Lee W., Bulletin ofEnvironmenta1 Contamination and Toxicology 1996,57,341).
Genotoxicity of humic acid A single oral dose of humic acid given to mice at 100 mg/kg body weight induced chromosome damage and numerical aberrations (aneuploidy) in the intestinal cells. Humic acid is a complex by-product arising from the degradation of soil organic matter. The Italian investigators claim that this is the first demonstration of its genotoxic activity in vivo (Bernacchi F. et al., Mutagenesis 1996,11,467).
Polnoks R - developmental toxicity Polnoks R (poly-1,2dihydro_2,2&rimethylquinoline), an antioxidant used in the processing of elastomers, was given by stomach tube to female rats on days 6-15 of pregnancy. It was embryo- and foetotoxic and produced birth defects at the top and maternally toxic dose of 670 mg/kg body weight/ day. Foetal and maternal toxicity were also seen at 340 mg/kg body weight/day. There was some indication of a foetotox;c effect at the lowest tested dose of 170 mg/kg body weight/day (Sitarek K. et al., Teratogenesis, Carcinogenesis and Mutagenesis 1996, 16, 75).
Nervous system effects from low levels of styrene Subtle central and peripheral nervous system changes were detected in 41 workers in Taiwanese plants producing fibreglass-reinforced plastics. The mean daily styrene exposure was 22 ppm (range 0-181 ppm); the (8-hr) exposure limit in the UK is 100 ppm (Tsai S.-Y. and Chen J.-D., Neurotoxicology and Temtology 1996, 18,463).
Thiuram mix sensitization - elicitation threshold A Danish investigation .indicates that synthetic sweat may be a more rel.evant medium for patch-testing for thiuram sensitization than is petrolatum. Even with the more appropriate vehicle, an acceptable threshold for leachable thiurams in rubber gloves was not identified from the patch-testing of 19 patients, since sensitization reactions were elicited at the lowest test concentration of 0.005% thiuram mix. The acceptable threshold was considered likely to be “substantially less than 0.001 mg/cm2” (Knudsen B.B. and Menne T., Contact Dermatitis 1996,34, 410). Prenatal PCB exposure and IQ A battery of IQ and achievement tests was conducted in 212 ll-yr-old children, 167 of whom were born to women wlho had eaten PCB-contaminated fish from Lake Michigan and 45 of whom were born to women who had not. The most highly exposed group of children were three times as likely to have low IQ scores (P< 0.001) and twice as likely to be at least 2 yr behind in reading comprehension (P-0.03). The investigators concluded that prenatal exposure to PCBs “in concentrations slightly higher than those in the general population can have a long-term impact on intellectual function” (Jacobson J.L. and Jacobson
Section
1197
S.W., New England Journal ofMedicine 1996,335, 783).
Mutagenic catalyst in dentine bonding material Tri-n-butyl borane oxide, a catalyst of a dentine bonding agent, was mutagenic in Salmonella typhimurium (Ames test) in the absente of metabolic activation. The mutagenic potential was detectable when the catalyst was dissolved in saline, but not when dimethyl sulfoxide was the solvent (Schweikl H. et al, Biomaterials 1996, 17, 1451).
Photocopier toner dust A 3%yr-old man who worked in a newspaper agency developed a disease of the lymph system (mediastinal lymphadenopathy) and lung damage (granulomatous pneumonitis) associated with his exposure to photocopier toner dust. The link was based on the detection of copper in both lung biopsies and the toner. His symptoms, including dry cough and breathing difficulty, began after about 6 months’ employment at the agency (Armbruster C. et al., Lancet 1996,348, 690).
Oestrogenic activity and nonylphenol Nonylphenol, which is present in the environment, including drinking water, has been shown to be oestrogenic (causing increases in uterine weight, uterine protein and DNA contents, and uterine peroxidase activity) when given as a single intraperitoneal injection at 1 mg/animal (about 20 mg/kg body weight) to immature rats. The effects mimicked those seen with oestradiol (tested at doses of about 0.05 mg/kg body weight). The investigators reported that “nonylphenol was ineffective when used at a pg range”, indicating that it is 1000 to 2OOO-fold less potent than estradiol (Lee P.-C. and Lee W., Bulletin ofEnvironmenta1 Contamination and Toxicology 1996,57,341).
Genotoxicity of humic acid A single oral dose of humic acid given to mice at 100 mg/kg body weight induced chromosome damage and numerical aberrations (aneuploidy) in the intestinal cells. Humic acid is a complex by-product arising from the degradation of soil organic matter. The Italian investigators claim that this is the first demonstration of its genotoxic activity in vivo (Bernacchi F. et al., Mutagenesis 1996,11,467).