@article{mercadante_herrera_pettiglio_foster_johnson_dorman_bartnikas_2016, title={The effect of high dose oral manganese exposure on copper, iron and zinc levels in rats}, volume={29}, ISSN={["1572-8773"]}, DOI={10.1007/s10534-016-9924-6}, abstractNote={Manganese is an essential dietary nutrient and trace element with important roles in mammalian development, metabolism, and antioxidant defense. In healthy individuals, gastrointestinal absorption and hepatobiliary excretion are tightly regulated to maintain systemic manganese concentrations at physiologic levels. Interactions of manganese with other essential metals following high dose ingestion are incompletely understood. We previously reported that gavage manganese exposure in rats resulted in higher tissue manganese concentrations when compared with equivalent dietary or drinking water manganese exposures. In this study, we performed follow-up evaluations to determine whether oral manganese exposure perturbs iron, copper, or zinc tissue concentrations. Rats were exposed to a control diet with 10 ppm manganese or dietary, drinking water, or gavage exposure to approximately 11.1 mg manganese/kg body weight/day for 7 or 61 exposure days. While manganese exposure affected levels of all metals, particularly in the frontal cortex and liver, copper levels were most prominently affected. This result suggests an under-appreciated effect of manganese exposure on copper homeostasis which may contribute to our understanding of the pathophysiology of manganese toxicity.}, number={3}, journal={BIOMETALS}, author={Mercadante, Courtney J. and Herrera, Carolina and Pettiglio, Michael A. and Foster, Melanie L. and Johnson, Laura C. and Dorman, David C. and Bartnikas, Thomas B.}, year={2016}, month={Jun}, pages={417–422} }
 @article{foster_bartnikas_johnson_herrera_pettiglio_keene_taylor_dorman_2015, title={Pharmacokinetic Evaluation of the Equivalency of Gavage, Dietary, and Drinking Water Exposure to Manganese in F344 Rats}, volume={145}, ISSN={["1096-0929"]}, DOI={10.1093/toxsci/kfv047}, abstractNote={Concerns exist as to whether individuals may be at greater risk for neurotoxicity following increased manganese (Mn) oral intake. The goals of this study were to determine the equivalence of 3 methods of oral exposure and the rate (mg Mn/kg/day) of exposure. Adult male rats were allocated to control diet (10 ppm), high manganese diet (200 ppm), manganese-supplemented drinking water, and manganese gavage treatment groups. Animals in the drinking water and gavage groups were given the 10 ppm manganese diet and supplemented with manganese chloride (MnCl(2)) in drinking water or once-daily gavage to provide a daily manganese intake equivalent to that seen in the high-manganese diet group. No statistically significant difference in body weight gain or terminal body weights was seen. Rats were anesthetized following 7 and 61 exposure days, and samples of bile and blood were collected. Rats were then euthanized and striatum, olfactory bulb, frontal cortex, cerebellum, liver, spleen, and femur samples were collected for chemical analysis. Hematocrit was unaffected by manganese exposure. Liver and bile manganese concentrations were elevated in all treatment groups on day 61 (relative to controls). Increased cerebellum manganese concentrations were seen in animals from the high-manganese diet group (day 61, relative to controls). Increased (relative to all treatment groups) femur, striatum, cerebellum, frontal cortex, and olfactory bulb manganese concentrations were also seen following gavage suggesting that dose rate is an important factor in the pharmacokinetics of oral manganese. These data will be used to refine physiologically based pharmacokinetic models, extending their utility for manganese risk assessment by including multiple dietary exposures.}, number={2}, journal={TOXICOLOGICAL SCIENCES}, author={Foster, Melanie L. and Bartnikas, Thomas B. and Johnson, Laura C. and Herrera, Carolina and Pettiglio, Michael A. and Keene, Athena M. and Taylor, Michael D. and Dorman, David C.}, year={2015}, month={Jun}, pages={244–251} }
 @article{johnson_welch_whitfield_2013, title={Interactive effects of pesticide mixtures, predators, and environmental regimes on the toxicity of two pesticides to red-eyed tree frog larvae}, volume={32}, number={10}, journal={Environmental Toxicology and Chemistry}, author={Johnson, L. A. and Welch, B. and Whitfield, S. M.}, year={2013}, pages={2379–2386} }