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  Subjects -> ENVIRONMENTAL STUDIES (Total: 805 journals)
    - ENVIRONMENTAL STUDIES (736 journals)
    - POLLUTION (21 journals)
    - TOXICOLOGY AND ENVIRONMENTAL SAFETY (39 journals)
    - WASTE MANAGEMENT (9 journals)

ENVIRONMENTAL STUDIES (736 journals)            First | 1 2 3 4 5 6 7 8     

Hydrology: Current Research     Open Access   (Followers: 10)
IAMURE International Journal of Ecology and Conservation     Open Access   (Followers: 3)
Ideas in Ecology and Evolution     Open Access   (Followers: 11)
IEEE Transactions on Network and Service Management     Hybrid Journal   (Followers: 10)
IMA Journal of Management Mathematics     Hybrid Journal   (Followers: 1)
Indiana Journal of Global Legal Studies     Full-text available via subscription   (Followers: 1)
Indoor Air     Hybrid Journal   (Followers: 1)
Information Systems Management     Hybrid Journal   (Followers: 18)
Information Technology and Management     Hybrid Journal   (Followers: 11)
IngenierĂ­a HidrĂ¡ulica y Ambiental     Open Access  
Inhalation Toxicology     Hybrid Journal   (Followers: 7)
Integrated Environmental Assessment and Management     Hybrid Journal   (Followers: 5)
Interdisciplinary Environmental Review     Hybrid Journal   (Followers: 4)
Interfaces     Full-text available via subscription   (Followers: 6)
International Aquatic Research     Open Access   (Followers: 3)
International Archives of Occupational and Environmental Health     Hybrid Journal   (Followers: 4)
International Environmental Agreements: Politics, Law and Economics     Hybrid Journal   (Followers: 11)
International Gambling Studies     Hybrid Journal   (Followers: 6)
International Innovation - climate     Open Access  
International innovation. Environment     Open Access  
International Journal of Acarology     Hybrid Journal   (Followers: 1)
International Journal of Advancement in Earth and Enviromental Sciences     Open Access   (Followers: 1)
International Journal of African Renaissance Studies - Multi-, Inter- and Transdisciplinarity     Hybrid Journal   (Followers: 2)
International Journal of Agricultural and Environmental Information Systems     Full-text available via subscription   (Followers: 1)
International Journal of Alternative Propulsion     Hybrid Journal   (Followers: 1)
International Journal of Applied Psychoanalytic Studies     Hybrid Journal   (Followers: 2)
International Journal of Chinese Culture and Management     Hybrid Journal   (Followers: 2)
International Journal of Corrosion     Open Access   (Followers: 11)
International Journal of Critical Infrastructures     Hybrid Journal   (Followers: 3)
International Journal of Disaster Risk Reduction     Hybrid Journal   (Followers: 7)
International Journal of Disaster Risk Science     Open Access   (Followers: 10)
International Journal of Ecological Economics and Statistics     Full-text available via subscription  
International Journal of Ecology     Open Access   (Followers: 8)
International Journal of Ecology & Development     Full-text available via subscription   (Followers: 2)
International Journal of Energy and Environmental Engineering     Open Access   (Followers: 2)
International Journal of Environment     Open Access   (Followers: 3)
International Journal of Environment and Health     Hybrid Journal   (Followers: 7)
International Journal of Environment and Pollution     Hybrid Journal   (Followers: 5)
International Journal of Environment and Sustainable Development     Hybrid Journal   (Followers: 16)
International Journal of Environment and Waste Management     Hybrid Journal   (Followers: 6)
International Journal of Environment, Workplace and Employment     Hybrid Journal   (Followers: 3)
International Journal of Environmental Engineering     Hybrid Journal   (Followers: 5)
International Journal of Environmental Health Research     Hybrid Journal   (Followers: 2)
International Journal of Environmental Policy and Decision Making     Hybrid Journal   (Followers: 11)
International Journal of Environmental Protection     Open Access   (Followers: 13)
International Journal of Environmental Research and Public Health     Open Access   (Followers: 17)
International Journal of Environmental Science and Technology     Hybrid Journal   (Followers: 5)
International Journal of Environmental Studies     Hybrid Journal   (Followers: 10)
International Journal of Exergy     Hybrid Journal   (Followers: 4)
International Journal of Forest, Soil and Erosion     Open Access   (Followers: 4)
International Journal of Global Environmental Issues     Hybrid Journal   (Followers: 4)
International Journal of Global Warming     Hybrid Journal   (Followers: 5)
International Journal of Greenhouse Gas Control     Partially Free   (Followers: 6)
International Journal of Health Planning and Management     Hybrid Journal   (Followers: 7)
International Journal of Hygiene and Environmental Health     Hybrid Journal   (Followers: 6)
International Journal of Logistics Research and Applications : A Leading Journal of Supply Chain Management     Hybrid Journal   (Followers: 10)
International Journal of Philosophical Studies     Hybrid Journal   (Followers: 2)
International Journal of Phytoremediation     Hybrid Journal   (Followers: 2)
International Journal of Process Systems Engineering     Hybrid Journal   (Followers: 1)
International Journal of Recycling of Organic Waste in Agriculture     Open Access   (Followers: 2)
International Journal of Reliability and Safety     Hybrid Journal   (Followers: 8)
International Journal of Renewable Energy Development     Open Access   (Followers: 5)
International Journal of Social Sciences and Management     Open Access   (Followers: 1)
International Journal of Soil, Sediment and Water     Open Access   (Followers: 8)
International Journal of Stress Management     Full-text available via subscription   (Followers: 10)
International Journal of Sustainable Construction Engineering and Technology     Open Access   (Followers: 10)
International Journal of Sustainable Engineering     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Materials and Structural Systems     Hybrid Journal   (Followers: 5)
International Journal of Sustainable Society     Hybrid Journal   (Followers: 7)
International Journal of Testing     Hybrid Journal   (Followers: 1)
International Journal of the Commons     Open Access   (Followers: 3)
International Journal of Toxicology     Hybrid Journal   (Followers: 6)
International Journal of Water Resources and Environmental Engineering     Open Access   (Followers: 1)
International Studies in the Philosophy of Science     Hybrid Journal   (Followers: 12)
Interventions : International Journal of Postcolonial Studies     Hybrid Journal   (Followers: 11)
IOP Conference Series: Earth and Environmental Science     Open Access   (Followers: 7)
Iranian Studies     Hybrid Journal   (Followers: 11)
Irish Educational Studies     Hybrid Journal   (Followers: 2)
Irish Journal of Earth Sciences     Full-text available via subscription  
Irish Political Studies     Hybrid Journal   (Followers: 9)
ISLE: Interdisciplinary Studies in Literature and Environment     Hybrid Journal   (Followers: 1)
Isotopes in Environmental and Health Studies     Hybrid Journal   (Followers: 1)
Israel Studies     Full-text available via subscription   (Followers: 5)
Italian Studies     Hybrid Journal   (Followers: 6)
Jahangirnagar University Environmental Bulletin     Open Access  
Journal of Bioremediation & Biodegradation     Open Access   (Followers: 2)
Journal of Earth Science & Climatic Change     Open Access   (Followers: 7)
Journal of Petroleum & Environmental Biotechnology     Open Access   (Followers: 2)
Journal of Advanced Research in Civil and Environmental Engineering     Open Access   (Followers: 1)
Journal of Advances in Environmental Health Research     Open Access   (Followers: 2)
Journal of Agricultural and Environmental Ethics     Hybrid Journal   (Followers: 9)
Journal of Agricultural Biotechnology and Sustainable Development     Open Access  
Journal of Agricultural Chemistry and Environment     Open Access  
Journal of Agriculture and Environment     Open Access   (Followers: 1)
Journal of Agriculture and Environment for International Development     Open Access   (Followers: 6)
Journal of Agrobiology     Open Access   (Followers: 2)
Journal of Applied Ecology     Hybrid Journal   (Followers: 129)
Journal of Applied Meteorology and Climatology     Full-text available via subscription   (Followers: 9)
Journal of Applied Psychoanalytic Studies     Hybrid Journal   (Followers: 1)
Journal of Applied Sciences and Environmental Management     Open Access   (Followers: 1)

  First | 1 2 3 4 5 6 7 8     

Journal Cover   Journal of Applied Toxicology
  [SJR: 0.799]   [H-I: 53]   [10 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0260-437X - ISSN (Online) 1099-1263
   Published by John Wiley and Sons Homepage  [1598 journals]
  • Investigation of ifosfamide and chloroacetaldehyde renal toxicity through
           integration of in vitro liver–kidney microfluidic data and
           pharmacokinetic‐system biology models
    • Authors: Eric Leclerc; Jeremy Hamon, Frederic Yves Bois
      Abstract: We have integrated in vitro and in silico data to describe the toxicity of chloroacetaldehyde (CAA) on renal cells via its production from the metabolism of ifosfamide (IFO) by hepatic cells. A pharmacokinetic (PK) model described the production of CAA by the hepatocytes and its transport to the renal cells. A system biology model was coupled to the PK model to describe the production of reactive oxygen species (ROS) induced by CAA in the renal cells. In response to the ROS production, the metabolism of glutathione (GSH) and its depletion were modeled by the action of an NFE2L2 gene‐dependent pathway. The model parameters were estimated in a Bayesian context via Markov Chain Monte Carlo (MCMC) simulations based on microfluidic experiments and literature in vitro data. Hepatic IFO and CAA in vitro intrinsic clearances were estimated to be 1.85 x 10‐9 μL s–1 cell–1 and 0.185 x 10‐9 μL s–1 cell–1,respectively (corresponding to an in vivo intrinsic IFO clearance estimate of 1.23 l h–1, to be compared to IFO published values ranging from 3 to 10 l h–1). After model calibration, simulations made at therapeutic doses of IFO showed CAA renal intracellular concentrations ranging from 11 to 131 μM. Intracellular CAA concentrations above 70 μM induced intense ROS production and GSH depletion. Those responses were time and dose dependent, showing transient and non‐linear kinetics. Those results are in agreement with literature data reporting that intracellular CAA toxic concentrations range from 35 to 320 μM, after therapeutic ifosfamide dosing. The results were also consistent with in vitro CAA renal cytotoxicity data. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-07-07T23:55:07.334278-05:
      DOI: 10.1002/jat.3191
       
  • Developing Xenopus embryos recover by compacting and expelling single wall
           carbon nanotubes
    • Authors: Brian D. Holt; Joseph H. Shawky, Kris Noel Dahl, Lance A. Davidson, Mohammad F. Islam
      Abstract: Single wall carbon nanotubes are high aspect ratio nanomaterials being developed for use in materials, technological and biological applications due to their high mechanical stiffness, optical properties and chemical inertness. Because of their prevalence, it is inevitable that biological systems will be exposed to nanotubes, yet studies of the effects of nanotubes on developing embryos have been inconclusive and are lacking for single wall carbon nanotubes exposed to the widely studied model organism Xenopus laevis (African clawed frog). Microinjection of experimental substances into the Xenopus embryo is a standard technique for toxicology studies and cellular lineage tracing. Here we report the surprising finding that superficial (12.5 ± 7.5 µm below the membrane) microinjection of nanotubes dispersed with Pluronic F127 into one‐ to two‐cell Xenopus embryos resulted in the formation and expulsion of compacted, nanotube‐filled, punctate masses, at the blastula to mid‐gastrula developmental stages, which we call “boluses.” Such expulsion of microinjected materials by Xenopus embryos has not been reported before and is dramatically different from the typical distribution of the materials throughout the progeny of the microinjected cells. Previous studies of microinjections of nanomaterials such as nanodiamonds, quantum dots or spherical nanoparticles report that nanomaterials often induce toxicity and remain localized within the embryos. In contrast, our results demonstrate an active recovery pathway for embryos after exposure to Pluronic F127‐coated nanotubes, which we speculate is due to a combined effect of the membrane activity of the dispersing agent, Pluronic F127, and the large aspect ratio of nanotubes. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-07-07T08:31:30.511702-05:
      DOI: 10.1002/jat.3203
       
  • Safety concerns of herbal products and traditional Chinese herbal
           medicines: dehydropyrrolizidine alkaloids and aristolochic acid
    • Authors: Bryan L. Stegelmeier; Ammon W. Brown, Kevin D. Welch
      Abstract: In many countries, including the United States, herbal supplements, tisanes and vegetable products, including traditional Chinese medicines, are largely unregulated and their content is not registered, monitored or verified. Consequently, potent plant toxins including dehydropyrrolizidine alkaloids and other potential carcinogens can contaminate these products. As herbal and food supplement producers are left to their own means to determine the safety and purity of their products prior to marketing, disturbingly often good marketing practices currently in place are ignored and content is largely undocumented. Historical examples of poisoning and health issues relating to plant material containing dehydopyrrolizidine alkaloids and aristolochic acids were used as examples to demonstrate the risk and potential toxicity of herbal products, food supplements, or traditional medicines. More work is needed to educate consumers of the potential risk and require the industry to be more responsible to verify the content and insure the safety of their products. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.
      PubDate: 2015-07-07T07:20:45.37385-05:0
      DOI: 10.1002/jat.3192
       
  • Biological effects and toxicity of diluted bitumen and its constituents in
           freshwater systems
    • Authors: William A. Dew; Alice Hontela, Stewart B. Rood, Greg G. Pyle
      Abstract: Approximately 50 billion cubic meters of bitumen resides within the oil sands region of Alberta, Canada. To facilitate the transport of bitumen from where it is extracted to where it is processed, the bitumen is diluted with natural gas condensate (‘dilbit’), synthetic crude from hydrocracking bitumen (‘synbit’), or a mixture of both (‘dilsynbit’). A primary consideration for the effects of diluted bitumen products on freshwater organisms and ecosystems is whether it will float on the water surface or sink and interact with the stream or lake sediments. Evidence from a spill near Kalamazoo, MI, in 2010 and laboratory testing demonstrate that the nature of the spill and weathering of the dilbit, synbit or dilsynbit prior to and during contact with water will dictate whether the product floats or sinks. Subsequent toxicological data on the effects of dilbit and other diluted bitumen products on freshwater organisms and ecosystems are scarce. However, the current literature indicates that dilbit or bitumen can have significant effects on a wide variety of toxicological endpoints. This review synthesizes the currently available literature concerning the fate and effects of dilbit and synbit spilled into freshwater, and the effects of bitumen and bitumen products on aquatic organisms and ecosystems. Dilbit is likely to provide ecological impacts that are similar to and extend from those that follow from exposure to lighter crude oil, but the prospect of bitumen settling after binding to suspended sediments elevates the risk for benthic impacts in streams and lakes. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-07-07T06:57:19.642231-05:
      DOI: 10.1002/jat.3196
       
  • Accumulation and toxicity of intravenously‐injected functionalized
           graphene oxide in mice
    • Abstract: Graphene and its functionalized derivatives have recently emerged as interesting nanomaterials with promising applications in biomedicine. In this study, the long‐term in vivo biodistribution of intravenously injected nanographene oxide (NGO) functionalized with poly sodium 4‐styrenesulfonate (PSS) was systematically examined and the potential toxicity over 6 months of NGO‐PSS nanoparticles was investigated. Our results showed that the nanoparticles mainly accumulate in the lung, liver and spleen, where they persist for at least 6 months. These nanoparticles result in acute liver injury and chronic inflammation of the lung, liver and spleen, as evidenced by blood biochemistry results and histological examinations. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-06-23T04:54:20.261061-05:
      DOI: 10.1002/jat.3187
       
  • Zebrafish as a model for studying the developmental neurotoxicity of
           propofol
    • Authors: Peipei Guo; Zhibin Huang, Tao Tao, Xiaohui Chen, Wenqing Zhang, Yiyue Zhang, Chunshui Lin
      Abstract: Anesthetics can cause widespread apoptotic neurodegeneration and adverse effects on synaptogenesis during early postnatal life. Synaptogenesis correlates with several proteins, including myelin basic protein (MBP). However, little is known about the adverse effects of exposure to propofol on MBP, particularly during embryonic development. Our goal was to use zebrafish to explore the effect of propofol on embryonic development, apoptosis and MBP expression. Zebrafish embryos were exposed to propofol at defined doses and stages from 6 to 48 h postfertilization by immersion. The survival rate, hatchability, aberration rate, cell apoptosis and gene expression were analyzed at defined stages. Analysis revealed that doses of 1, 2 and 3 µg ml–1 propofol were reasonable anesthetic concentrations for zebrafish embryos. These doses of propofol caused a significant decrease in hatchability and an increase in aberration rate. Moreover, 6 days postfertilization (dpf) larvae are anesthetized by immersion into water containing 1, 2 or 3 µg ml–1 of propofol. The number of apoptotic cells in the head of propofol‐treated 36 h postfertilization embryos were significantly increased, and the expression of caspases‐3, ‐8 and ‐9 were upregulated. Apoptosis was also induced in the brain of 3 dpf larvae exposed to propofol. However, propofol caused a decrease in mbp gene and protein (dose‐dependent) expression levels in the central nervous system of 3 dpf zebrafish. These data show that embryonic exposure to propofol is neurotoxic, causing increased apoptosis and decreased MBP expression. We believe zebrafish can be used as a novel model to explore the mechanisms of propofol neurotoxicity. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-06-23T04:30:04.96548-05:0
      DOI: 10.1002/jat.3183
       
  • Biological effect of food additive titanium dioxide nanoparticles on
           intestine: an in vitro study
    • Abstract: Titanium dioxide nanoparticles (TiO2 NPs) are widely found in food‐related consumer products. Understanding the effect of TiO2 NPs on the intestinal barrier and absorption is essential and vital for the safety assessment of orally administrated TiO2 NPs. In this study, the cytotoxicity and translocation of two native TiO2 NPs, and these two TiO2 NPs pretreated with the digestion simulation fluid or bovine serum albumin were investigated in undifferentiated Caco‐2 cells, differentiated Caco‐2 cells and Caco‐2 monolayer. TiO2 NPs with a concentration less than 200 µg ml–1 did not induce any toxicity in differentiated cells and Caco‐2 monolayer after 24 h exposure. However, TiO2 NPs pretreated with digestion simulation fluids at 200 µg ml–1 inhibited the growth of undifferentiated Caco‐2 cells. Undifferentiated Caco‐2 cells swallowed native TiO2 NPs easily, but not pretreated NPs, implying the protein coating on NPs impeded the cellular uptake. Compared with undifferentiated cells, differentiated ones possessed much lower uptake ability of these TiO2 NPs. Similarly, the traverse of TiO2 NPs through the Caco‐2 monolayer was also negligible. Therefore, we infer the possibility of TiO2 NPs traversing through the intestine of animal or human after oral intake is quite low. This study provides valuable information for the risk assessment of TiO2 NPs in food. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-06-23T04:06:17.670193-05:
      DOI: 10.1002/jat.3171
       
  • The toxic effects of Bisphenol A on the mouse spermatocyte GC‐2 cell
           line: the role of the
           Ca2+‐calmodulin‐Ca2+/calmodulin‐dependent protein kinase
           II axis
    • Authors: Wenyi Qian; Yixin Wang, Jingying Zhu, Changfei Mao, Qiang Wang, Fei Huan, Jie Cheng, Yanqing Liu, Jun Wang, Hang Xiao
      Abstract: Bisphenol A (BPA), an endocrine‐disrupting chemical (EDC), is known to induce male reproductive toxicity in rodents. However, its toxic effects on the germ cells are still poorly understood. It has been proposed that Ca2+ homeostasis and Ca2+ sensors, including calmodulin (CaM) and calmodulin‐dependent protein kinase II (CaMKII), play critical roles in spermatogenesis. Therefore, in the present study, we aimed to investigate whether a perturbation in Ca2+‐CaM‐CaMKII signaling was involved in the BPA‐induced injury to mouse spermatocyte GC‐2spd (ts) (GC‐2) cells. Our results showed that BPA (range from 0.2 to 20 μM) induced obvious GC‐2 cell injury, including decreased cell viability, the release of mitochondrial cytochrome c and the activation of caspase‐3. However, these processes could be partially abrogated by pretreatment with a Ca2+ chelator (BAPTA/AM), a CaM antagonist (W7) or a CaMKII inhibitor (KN93). These results, taken together, indicate that BPA exposure contributes to male germ cell injury, which may be partially mediated through a perturbation in Ca2+/CaM/CaMKII signaling and the mitochondrial apoptotic process. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-06-18T07:08:22.642556-05:
      DOI: 10.1002/jat.3188
       
  • Chromium oxide nanoparticle‐induced genotoxicity and
           p53‐dependent apoptosis in human lung alveolar cells
    • Authors: Violet Aileen Senapati; Abhishek Kumar Jain, Govind Sharan Gupta, Alok Kumar Pandey, Alok Dhawan
      Abstract: Chromium oxide (Cr2O3) nanoparticles (NPs) are being increasingly used as a catalyst for aromatic compound manufacture, abrading agents and as pigments (e.g., Viridian). Owing to increased applications, it is important to study the biological effects of Cr2O3 NPs on human health. The lung is one of the main exposure routes to nanomaterials; therefore, the present study was designed to determine the genotoxic and apoptotic effect of Cr2O3 NPs in human lung epithelial cells (A549). The study also elucidated the molecular mechanism of its toxicity. Cr2O3 NPs led to DNA damage, which was deduced by comet assay and cytokinesis block micronucleus assay. The damage could be mediated by the increased levels of reactive oxygen species. Further, the oxygen species led to a decrease in mitochondrial membrane potential and an increase in the ratio of BAX/Bcl‐2 leading to mitochondria‐mediated apoptosis induced by Cr2O3 NPs, which ultimately leads to cell death. Hence, there is a need of regulations to be imposed in NP usage. The study provided insight into the caspase‐dependent mechanistic pathway of apoptosis. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-06-18T06:49:15.366062-05:
      DOI: 10.1002/jat.3174
       
  • Analysis of cytotoxic effects of silver nanoclusters on human peripheral
           blood mononuclear cells ‘in vitro’
    • Abstract: The antimicrobial properties of silver nanoparticles (AgNPs) have made these particles one of the most used nanomaterials in consumer products. Therefore, an understanding of the interactions (unwanted toxicity) between nanoparticles and human cells is of significant interest. The aim of this study was to assess the in vitro cytotoxicity effects of silver nanoclusters (AgNC, < 2 nm diameter) on peripheral blood mononuclear cells (PBMC). Using flow cytometry and comet assay methods, we demonstrate that exposure of PBMC to AgNC induced intracellular reactive oxygen species (ROS) generation, DNA damage and apoptosis at 3, 6 and 12 h, with a dose‐dependent response (0.1, 1, 3, 5 and 30 µg ml–1). Advanced electron microscopy imaging of complete and ultrathin‐sections of PBMC confirmed the cytotoxic effects and cell damage caused by AgNC. The present study showed that AgNC produced without coating agents induced significant cytotoxic effects on PBMC owing to their high aspect ratio and active surface area, even at much lower concentrations (
      PubDate: 2015-06-17T06:02:30.505112-05:
      DOI: 10.1002/jat.3190
       
  • Sub‐chronic exposure to fluoride impacts the response to a
           subsequent nephrotoxic treatment with gentamicin
    • Abstract: Fluoride is an important groundwater contaminant, and more than 200 million people are exposed to high fluoride levels in drinking water, the major source of fluoride exposure. Exposure above 2 ppm of fluoride is associated with renal impairment in humans. In rats, moderate levels of fluoride induce kidney injury at early stages in which the glomerular filtration rate (GFR) is not altered. In the present study, we investigated if sub‐nephrotoxic stimulus induced by fluoride might impact the response to a subsequent nephrotoxic treatment with gentamicin. Male Wistar rats (~21 days) were exposed to 0, 15 or 50 ppm of fluoride through drinking water during 40 days. Afer that, rats were co‐exposed to gentamicin (40 mg kg–1 day–1, 7 days). Gentamicin induced a marked decrease in the GFR and an increase in urinary levels as well as the protein and mRNA expression of biomarkers of early kidney injury, such as Kim‐1. Interestingly, gentamicin nephrotoxicity was less pronounced in groups previously exposed to fluoride than in the group only treated with gentamicin. Fluoride induced Hsp72, a cytoprotective molecule, which might have improved the response against gentamicin. Moreover, fluoride decreased the expression of megalin, a molecule necessary for internalization of gentamicin into the proximal tubule, potentially reducing gentamicin accumulation. The present results suggest that fluoride reduced gentamicin‐induced nephrotoxicity by inducing a compensatory response carried out by Hsp72 and by decreasing gentamicin accumulation. These findings should not be interpreted to suggest that fluoride is a protective agent as megalin deficiency could lead to serious adverse effects on the kidney physiology. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-06-17T05:36:53.142301-05:
      DOI: 10.1002/jat.3186
       
  • Distribution and biomarker of carbon‐14 labeled fullerene C60
           ([14C(U)]C60) in pregnant and lactating rats and their offspring after
           maternal intravenous exposure
    • Authors: Rodney W. Snyder; Timothy R. Fennell, Christopher J. Wingard, Ninell P. Mortensen, Nathan A. Holland, Jonathan H. Shannahan, Wimal Pathmasiri, Anita H. Lewin, Susan C. J. Sumner
      Abstract: A comprehensive distribution study was conducted in pregnant and lactating rats exposed to a suspension of uniformly carbon‐14 labeled C60 ([14C(U)]C60). Rats were administered [14C(U)]C60 (~0.2 mg [14C(U)]C60 kg–1 body weight) or 5% polyvinylpyrrolidone (PVP)‐saline vehicle via a single tail vein injection. Pregnant rats were injected on gestation day (GD) 11 (terminated with fetuses after either 24 h or 8 days), GD15 (terminated after 24 h or 4 days), or GD18 (terminated after 24 h). Lactating rats were injected on postnatal day 8 and terminated after 24 h, 3 or 11 days. The distribution of radioactivity in pregnant dams was influenced by both the state of pregnancy and time of termination after exposure. The percentage of recovered radioactivity in pregnant and lactating rats was highest in the liver and lungs. Radioactivity was quantitated in over 20 tissues. Radioactivity was found in the placenta and in fetuses of pregnant dams, and in the milk of lactating rats and in pups. Elimination of radioactivity was < 2% in urine and feces at each time point. Radioactivity remained in blood circulation up to 11 days after [14C(U)]C60 exposure. Biomarkers of inflammation, cardiovascular injury and oxidative stress were measured to study the biological impacts of [14C(U)]C60 exposure. Oxidative stress was elevated in female pups of exposed dams. Metabolomics analysis of urine showed that [14C(U)]C60 exposure to pregnant rats impacted the pathways of vitamin B, regulation of lipid and sugar metabolism and aminoacyl‐tRNA biosynthesis. This study demonstrated that [14C(U)]C60 crosses the placenta at all stages of pregnancy examined, and is transferred to pups via milk. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-06-17T04:13:53.329712-05:
      DOI: 10.1002/jat.3177
       
  • Complement C5a–C5aR interaction enhances MAPK signaling pathway
           activities to mediate renal injury in trichloroethylene sensitized BALB/c
           mice
    • Abstract: We have previously shown complement activation as a possible mechanism for trichloroethylene (TCE) sensitization, leading to multi‐organ damage including the kidneys. In particular, excessive deposition of C5 and C5b‐9‐the membrane attack complex, which can generate significant tissue damage, was observed in the kidney tissue after TCE sensitization. The present study tested the hypothesis that anaphylatoxin C5a binding to its receptor C5aR mediates renal injury in TCE‐sensitized BALB/c mice. BALB/c mice were sensitized through skin challenge with TCE, with or without pretreatment by the C5aR antagonist W54011. Kidney histopathology and the renal functional test were performed to assess renal injury, and immunohistochemistry and fluorescent labeling were carried out to assess C5a and C5aR expressions. TCE sensitization up‐regulated C5a and C5aR expressions in kidney tissue, generated inflammatory infiltration, renal tubule damage, glomerular hypercellularity and impaired renal function. Antagonist pretreatment blocked C5a binding to C5aR and attenuated TCE‐induced tissue damage and renal dysfunction. TCE sensitization also caused the deposition of major pro‐inflammatory cytokines IL‐2, TNF‐α and IFN‐γ in the kidney tissue (P 
      PubDate: 2015-06-10T05:53:11.117764-05:
      DOI: 10.1002/jat.3179
       
  • Hepatotoxicity mechanisms of isoniazid: A mini‐review
    • Abstract: Isoniazid (INH) is an antituberculosis drug associated with idiosyncratic liver injury in susceptible patients. INH‐induced hepatotoxicity remains a significant clinical problem, but the underlying mechanisms are still unclear, despite the growing evidence that INH and/or its major metabolite, hydrazine, play an important role in hepatotoxicity. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-06-10T05:47:41.354338-05:
      DOI: 10.1002/jat.3175
       
  • Bik subcellular localization in response to oxidative stress induced by
           chemotherapy, in Two different breast cancer cell lines and a
           Non‐tumorigenic epithelial cell line
    • Abstract: Cancer chemotherapy remains one of the preferred therapeutic modalities against malignancies despite its damaging side effects. An expected outcome while utilizing chemotherapy is apoptosis induction. This is mainly regulated by a group of proteins known as the Bcl‐2 family, usually found within the endoplasmic reticulum or the mitochondria. Recently, these proteins have been located in other sites and non‐canonic functions have been unraveled. Bik is a pro‐apoptotic protein, which becomes deregulated in cancer, and as apoptosis is associated with oxidative stress generation, our objective was to determine the subcellular localization of Bik either after a direct oxidative insult due to H2O2, or indirectly by cisplatin, an antineoplastic agent. Experiments were performed in two human transformed mammary gland cell lines MDA‐MB‐231 and MCF‐7, and one non‐tumorigenic epithelial cell line MCF‐10A. Our results showed that in MCF‐7, Bik is localized within the cytosol and that after oxidative stress treatment it translocates into the nucleus. However, in MDA‐MB‐231, Bik localizes in the nucleus and translocates to the cytosol. In MCF10A Bik did not change its cellular site after either treatment. Interestingly, MCF10A were more resistant to cisplatin than transformed cell lines. This is the first report showing that Bik is located in different cellular compartments depending on the cancer stage, and it has the ability to change its subcellular localization in response to oxidative stress. This is associated with increased sensitivity when exposed to toxic agents, thus rendering novel opportunities to study new therapeutic targets allowing the development of more active and less harmful agents. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-06-09T06:56:58.217996-05:
      DOI: 10.1002/jat.3173
       
  • Bisphenol A affects placental layers morphology and angiogenesis during
           early pregnancy phase in mice
    • Authors: Sabrina Tait; Roberta Tassinari, Francesca Maranghi, Alberto Mantovani
      Abstract: Bisphenol A (BPA) is a widespread endocrine disrupter mainly used in food contact plastics. Much evidence supports the adverse effects of BPA, particularly on susceptible groups such as pregnant women. The present study considered placental development – relevant for pregnancy outcomes and fetal nutrition/programming – as a potential target of BPA. Pregnant CD‐1 mice were administered per os with vehicle, 0.5 (BPA05) or 50 mg kg−1 (BPA50) body weight day−1 of BPA, from gestational day (GD) 1 to GD11. At GD12, BPA50 induced significant degeneration and necrosis of giant cells, increased vacuolization in the junctional zone in the absence of glycogen accumulation and reduction of the spongiotrophoblast layer. In addition, BPA05 induced glycogen depletion as well as significant nuclear accumulation of β‐catenin in trophoblasts of labyrinthine and spongiotrophoblast layers, supporting the activation of the Wnt/β‐catenin pathway. Transcriptomic analysis indicated that BPA05 promoted and BPA50 inhibited blood vessel development and branching; morphologically, maternal vessels were narrower in BPA05 placentas, whereas embryonic and maternal vessels were irregularly dilated in the labyrinth of BPA50 placentas. Quantitative polymerase chain reaction evidenced an estrogen receptor β induction by BPA50, which did not correspond to downstream genes activation; indeed, the transcription factor binding sites analysis supported the AhR/Arnt complex as regulator of BPA50‐modulated genes. Conversely, Creb appeared as the main transcription factor regulating BPA05‐modulated genes. Embryonic structures (head, forelimb) showed divergent perturbations upon BPA05 or BPA50 exposure, potentially related to unbalanced embryonic nutrition and/or to modulation of genes involved in embryo development. Our findings support placenta as an important target of BPA, even at environmentally relevant dose levels. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-06-09T05:54:55.40227-05:0
      DOI: 10.1002/jat.3176
       
  • Probabilistic hazard assessment for skin sensitization potency by
           dose–response modeling using feature elimination instead of
           quantitative structure–activity relationships
    • Abstract: Supervised learning methods promise to improve integrated testing strategies (ITS), but must be adjusted to handle high dimensionality and dose–response data. ITS approaches are currently fueled by the increasing mechanistic understanding of adverse outcome pathways (AOP) and the development of tests reflecting these mechanisms. Simple approaches to combine skin sensitization data sets, such as weight of evidence, fail due to problems in information redundancy and high dimensionality. The problem is further amplified when potency information (dose/response) of hazards would be estimated. Skin sensitization currently serves as the foster child for AOP and ITS development, as legislative pressures combined with a very good mechanistic understanding of contact dermatitis have led to test development and relatively large high‐quality data sets. We curated such a data set and combined a recursive variable selection algorithm to evaluate the information available through in silico, in chemico and in vitro assays. Chemical similarity alone could not cluster chemicals' potency, and in vitro models consistently ranked high in recursive feature elimination. This allows reducing the number of tests included in an ITS. Next, we analyzed with a hidden Markov model that takes advantage of an intrinsic inter‐relationship among the local lymph node assay classes, i.e. the monotonous connection between local lymph node assay and dose. The dose‐informed random forest/hidden Markov model was superior to the dose‐naive random forest model on all data sets. Although balanced accuracy improvement may seem small, this obscures the actual improvement in misclassifications as the dose‐informed hidden Markov model strongly reduced " false‐negatives" (i.e. extreme sensitizers as non‐sensitizer) on all data sets. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-06-05T07:10:27.019247-05:
      DOI: 10.1002/jat.3172
       
  • Difficulties in establishing regulations for engineered nanomaterials and
           considerations for policy makers: avoiding an unbalance between benefits
           and risks
    • Abstract: Current evidence of engineered nanomaterials’ (ENM) toxicity has led to a latent concern about hazards for both humans and the environment. For this reason, some efforts have been made to suggest frameworks or other guidance to regulate ENM handling; however, the real exposure risk to humans has not been well established. The aims of this work were to analyze the difficulties in establishing regulations for ENM and to discuss some considerations that may be helpful for policy makers involved in the regulation of ENM. Difficulties in establishing regulations are based on the novel properties of ENM associated with cytotoxic effects, the insufficiency of standardized methods to test those effects and the lack of epidemiological evidence of ENM toxicity, especially in occupational settings. Nevertheless, we offer some suggestions for establishing regulations, which include frameworks oriented towards protecting personnel exposed to ENM without decreasing production. In addition, we propose an ENM data sheet to offer available information of ENM. Finally, ethical aspects should also be considered in developing ENM regulations because every person who is working around or consuming ENM has the right to be informed about the potential risk. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-06-05T07:04:23.407074-05:
      DOI: 10.1002/jat.3180
       
  • Non‐clinical safety evaluation of repeated intramuscular
           administration of the AS15 immunostimulant combined with various antigens
           in rabbits and cynomolgus monkeys
    • Abstract: Combination of tumor antigens with immunostimulants is a promising approach in cancer immunotherapy. We assessed animal model toxicity of AS15 combined with various tumor antigens: WT1 (rabbits), or p501, dHER2 and recPRAME (cynomolgus monkeys), administered in seven or 20 dose regimens versus a saline control. Clinical and ophthalmological examinations, followed by extensive post‐mortem pathological examinations, were performed on all animals. Blood hematology and biochemistry parameters were also assessed. Antigen‐specific antibody titers were determined by enzyme‐linked immunosorbent assay. Additional assessments in monkeys included electrocardiography and immunohistochemical evaluations of the p501 expression pattern. Transient increases in body temperature were observed 4 h or 24 h after injections of recPRAME + AS15 and dHER2 + AS15. Edema and erythema were observed up to 1 week after most injections of recPRAME + AS15 and all injections of dHER2 + AS15. No treatment‐related effects were observed for electrocardiography parameters. Mean fibrinogen levels were significantly higher in all treated groups compared to controls, but no differences could be observed at the end of the treatment‐free period. Transient but significant differences in biochemistry parameters were observed post‐injection: lower albumin/globulin ratios (p501 + AS15), and higher bilirubin, urea and creatinine (dHER2 + AS15). Pathology examinations revealed significant increases in axillary lymph node mean weights (recPRAME + AS15) compared to controls. A 100% seroconversion rate was observed in all treated groups, but not in controls. p501 protein expression was observed in prostates of all monkeys from studies assessing p501 + AS15. These results suggest a favorable safety profile of the AS15‐containing candidate vaccines, supporting the use of AS15 for clinical development of potential anticancer vaccines. Copyright © 2015 The
      Authors . Journal of Applied Toxicology Published by John Wiley & Sons Ltd.
      PubDate: 2015-06-01T20:18:59.225297-05:
      DOI: 10.1002/jat.3167
       
  • Toxicogenomic responses of human liver HepG2 cells to silver nanoparticles
    • Authors: Saura C. Sahu; Jiwen Zheng, Jeffrey J. Yourick, Robert L. Sprando, Xiugong Gao
      Abstract: The increased use of silver nanoparticles (AgNPs) in foods and cosmetics has raised public safety concerns. However, only limited knowledge exists on the effect of AgNPs on the cellular transcriptome. This study evaluated global gene expression profiles of human liver HepG2 cells exposed to 20 and 50 nm AgNPs for 4 and 24 h at 2.5 µg ml–1. Exposure to 20 nm AgNPs resulted in 811 altered genes after 4 h, but much less after 24 h. Exposure to 50 nm AgNPs showed minimal altered genes at both exposure times. The HepG2 cells responded to the toxic insult of AgNPs by transiently upregulating stress response genes such as metallothioneins and heat shock proteins. Functional analysis of the altered genes showed more than 20 major biological processes were affected, of which metabolism, development, cell differentiation and cell death were the most dominant categories. Several cellular pathways were also impacted by AgNP exposure, including the p53 signaling pathway and the NRF2‐mediated oxidative stress response pathway, which may lead to increased oxidative stress and DNA damage in the cell and potentially result in genotoxicity and carcinogenicity. Together, these results indicate that HepG2 cells underwent a multitude of cellular processes in response to the toxic insult of AgNP exposure, and suggest that toxicogenomic characterization of human HepG2 cells could serve as an alternative model for assessing toxicities of NPs. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.
      PubDate: 2015-05-26T00:18:17.224014-05:
      DOI: 10.1002/jat.3170
       
  • Short‐term, low‐dose cadmium exposure induces
           hyperpermeability in human renal glomerular endothelial cells
    • Authors: Liqun Li; Fengyun Dong, Dongmei Xu, Linna Du, Suhua Yan, Hesheng Hu, Corrinne G. Lobe, Fan Yi, Carolyn M. Kapron, Ju Liu
      Abstract: The kidney is the principal organ targeted by exposure to cadmium (Cd), a well‐known toxic metal. Even at a low level, Cd damages glomerular filtration. However, little is known about the effects of Cd on the glomerular endothelium, which performs the filtration function and directly interacts with Cd in blood plasma. In this study, we cultured human renal glomerular endothelial cells (HRGECs) in the presence of serum with treatment of a short term (1 h) and low concentration (1 μm) of Cd, which mimics the pattern of glomerular endothelium exposure to Cd in vivo. We found that this short‐term, low‐dose Cd exposure does not induce cytotoxicity, but increases permeability in HRGECs monolayers and redistributes adherens junction proteins vascular endothelial‐cadherin and β‐catenin. Though short‐term, low‐dose Cd exposure activates all three major mitogen activated protein kinases, only the inhibitor of p38 mitogen activated protein kinase partially prevents Cd‐induced hyperpermeability in HRGECs. Our data indicate that the presence of Cd in blood circulation might directly disrupt the glomerular endothelial cell barrier and contribute to the development of clinical symptoms of glomerular diseases. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-05-25T21:57:08.646349-05:
      DOI: 10.1002/jat.3168
       
  • Onset of hepatocarcinogen‐specific cell proliferation and cell cycle
           aberration during the early stage of repeated hepatocarcinogen
           administration in rats
    • Authors: Masayuki Kimura; Hajime Abe, Sayaka Mizukami, Takeshi Tanaka, Megu Itahashi, Nobuhiko Onda, Toshinori Yoshida, Makoto Shibutani
      Abstract: We have previously reported that a 28‐day treatment of carcinogens evoking target cell proliferation activates G1/S checkpoint function and apoptosis, as well as induction of aberrant ubiquitin D (Ubd) expression, suggesting disruptive spindle checkpoint function, in rats. The present study aimed to determine the onset time of rat liver cells to undergo carcinogen‐specific cell cycle aberration and proliferation. Animals were treated orally with a hepatocarcinogenic dose of methyleugenol or thioacetamide for 3, 7 or 28 days. For comparison, some animals were subjected to partial hepatectomy or treated with noncarcinogenic hepatotoxicants (acetaminophen, α‐naphthyl isothiocyanate or promethazine). Carcinogen‐specific liver cell kinetics appeared at day 28 as evident by increases of cell proliferation, p21Cip1+ cells, phosphorylated‐Mdm2+ cells and cleaved caspase 3+ cells, and upregulation of DNA damage‐related genes. Hepatocarcinogens also downregulated Rbl2 and upregulated Cdkn1a and Mdm2, and decreased Ubd+ cells co‐expressing phosphorylated‐histone H3 (p‐Histone H3) and p‐Histone H3+ cell ratio within the Ki‐67+ proliferating population. These results suggest that it takes 28 days to induce hepatocarcinogen‐specific early withdrawal of proliferating cells from M phase due to disruptive spindle checkpoint function as evidenced by reduction of Ubd+ cells staying at M phase. Disruption of G1/S checkpoint function reflected by downregulation of Rbl2 as well as upregulation of Mdm2 suggestive of sequestration of retinoblastoma protein is responsible for the facilitation of carcinogen‐induced cell proliferation at day 28. Accumulation of DNA damage probably in association with facilitation of p53 degradation by activation of Mdm2 may be a prerequisite for aberrant p21Cip1 activation, which is responsible for apoptosis. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-05-22T07:41:41.042646-05:
      DOI: 10.1002/jat.3163
       
  • RNA sequencing provides insights into the toxicogenomic response of ZF4
           cells to methyl methanesulfonate
    • Authors: Zhouquan Li; Yong Long, Liqiao Zhong, Guili Song, Xiaohua Zhang, Li Yuan, Zongbin Cui, Heping Dai
      Abstract: Whole genome transcriptomic studies are powerful for characterizing the molecular mechanisms underlying the physiological effects of chemicals, and are informative for environmental health risk assessment. Alkylating agents are an abundant class of chemicals that can damage DNA in the environment, and are used for anticancer treatments. Currently, little is known regarding the molecular mechanisms of toxic alkylating agents in zebrafish cell lines. In this study, RNA‐sequencing was used to investigate the transcriptomic responses of zebrafish ZF4 cells following exposure to the model genotoxicant methyl methanesulfonate (MMS). The half‐maximal inhibitory concentration (IC50) of MMS was 639.16 ± 61.8 µm, and apoptosis was induced within 24 h of exposure. RNA sequencing identified 3601 differentially expressed genes (DEGs) that were upregulated and 3037 that were downregulated. Gene ontology enrichment analysis revealed that most DEGs belonged to synthesis and metabolism categories. RNA‐associated processes were the most upregulated, while cell cycle and adhesion were the most repressed processes, and neuron‐related processes were the most downregulated developmental process. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis identified DNA damage repair, cell cycle, apoptosis and spliceosome as overrepresented terms. Six types of alternative splicing were detected. In total, 1156 alternative splicing DEGs were specifically expressed following MMS treatment, many of which belonged to metabolism and catabolic process categories. Cluster analysis of orthologs was able to extrapolate toxicotranscriptomic data between zebrafish and yeast. These results provide insight into the genome‐wide response of ZF4 cells following exposure to MMS, and this knowledge will inform future toxicogenomic data analysis and environmental health risk assessment. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-05-22T07:22:45.239857-05:
      DOI: 10.1002/jat.3147
       
  • A method for estimating the glomerular filtration rate in conscious
           monkeys
    • Authors: Hiroshi Satoh; Nana Nomiya, Daiki Imai, Shigeru Sato, Ken Sakurai, Kiyoshi Takasuna, Kazuhisa Furuhama
      Abstract: To establish a method for estimating the glomerular filtration rate (GFR) in conscious monkeys, the radiographic contrast medium iodixanol and the standard agent inulin were coadministered as tracers to male cynomolgus monkeys (Macaca fascicularis) as a bolus injection; blood was collected after 60, 90 and 120 min. An equation based on a single‐blood‐sample method derived from Jacobsson's formula was prepared using the data from healthy and saline‐ and gentamicin‐treated monkeys by a multisample strategy with iodixanol. The GFR using the equation with iodixanol was in agreement with that from the multisample method with inulin or iodixanol. When the GFR decreased to more than 60% of the basal reference level, serum creatinine concentrations tended to increase, whereas serum blood urea nitrogen concentrations fluctuated. The results suggest that the single‐sample‐blood method with iodixanol is a practical tool for estimating the monkey GFR in a toxicological research setting therefore minimizing animal sufferings. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-05-21T00:40:24.316596-05:
      DOI: 10.1002/jat.3178
       
  • Developmental toxicity and endocrine disruption of naphthenic acids on the
           early life stage of zebrafish (Danio rerio)
    • Authors: Jie Wang; Xiaofeng Cao, Yi Huang, Xiaoyan Tang
      Abstract: Oil sands process‐affected water (OSPW) has been reported to exhibit adverse effects on the environment and wildlife. Although the compounds responsible are unknown, naphthenic acids (NAs) have been considered to be implicated. The current study was designed to investigate whether NAs might cause developmental toxicity and endocrine disruption on the early life stage of zebrafish (Danio rerio). The success of embryo hatch was inhibited by 2.5 mg l–1 oil sands NAs (OS‐NAs) exposure, and both OSPW NAs and commercial NAs (C‐NAs) exposure resulted in a variety of developmental lesions in the fish larvae, such as yolk sac edema, pericardial edema and spinal malformation. The transcription of genes involved cytochrome P450 aromatase (CYP19a and CYP19b), estrogen receptors (ERα, ERβ1 and ERβ2), and vitellogenin (VTG) was analyzed to evaluate the endocrine disrupting effects of NAs. Significant up‐regulated gene expressions of CYP19b, ERα and VTG were observed in both OS‐NAs and C‐NAs groups, which indicated the deleteriously estrogenic potential of NAs. These results confirmed that NAs derived from crude petroleum could negatively impact the development and endocrine function of zebrafish, and be primarily responsible for the toxicity of OSPW. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-05-21T00:36:44.988264-05:
      DOI: 10.1002/jat.3166
       
  • Directional and color preference in adult zebrafish: Implications in
           behavioral and learning assays in neurotoxicology studies
    • Authors: Zachary A. Bault; Samuel M. Peterson, Jennifer L. Freeman
      Abstract: The zebrafish (Danio rerio) is a useful vertebrate model organism for neurological studies. While a number of behavior and learning assays are recently reported in the literature for zebrafish, many of these assays are still being refined. The initial purpose of this study was to apply a published T‐maze assay for adult zebrafish that measures how quickly an organism can discriminate between different color stimuli after receiving reinforcement to measure learning in a study investigating the later life impacts of developmental Pb exposure. The original results were inconclusive as the control group showed a directional and color preference. To assess directional preference further, a three‐chambered testing apparatus was constructed and rotated in several directions. The directional preference observed in males was alleviated by rotating the arms pointing west and east. In addition, color preference was investigated using all combinations of five different colors (orange, yellow, green, blue and purple). With directional preference alleviated results showed that both male and female zebrafish preferred colors of shorter wavelengths. An additional experiment tested changes in color preference due to developmental exposure to Pb in adult male zebrafish. Results revealed that Pb‐exposed males gained and lost certain color preferences compared to control males and the preference for short wavelengths was decreased. Overall, these results show that consideration and pretesting should be completed before applying behavioral and learning assays involving adult zebrafish to avoid innate preferences and confounding changes in neurotoxicology studies and that developmental Pb exposure alters color preferences in adult male zebrafish. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-05-20T21:12:27.765722-05:
      DOI: 10.1002/jat.3169
       
  • Effect‐directed identification of endocrine disruptors in plastic
           baby teethers
    • Abstract: Concerns have been raised regarding the human health effects of endocrine disrupting chemicals (EDCs), many of which are associated with and leaching from plastics. As infants are particularly vulnerable to EDCs, we have investigated whether plastic teethers for babies represent a relevant source of exposure. Applying effect‐directed analysis, we use bioassays to screen teethers, toys used to soothe a baby's teething ache, for endocrine activity and chemical analysis to identify the causative compounds. We detected significant endocrine activity in two of 10 plastic teethers. Those samples leached estrogenic and/or antiandrogenic activity as detected in the Yeast Estrogen Screen and Yeast Antiandrogen Screen. After sample fractionation, gas chromatography–mass spectrometry non‐target screening revealed that methyl‐, ethyl‐ and propylparaben were responsible for the observed estrogenic and antiandrogenic activity in one product. The second product is likely to contain at least six different antiandrogenic compounds that remain so far unidentified. This study demonstrates that plastic teethers can be a source of infant exposure to well‐established and unknown EDCs. Because of their limited value to the product, but potential toxicity, manufacturers should critically revisit the use of parabens in plastic teethers and further toys. Moreover, plastic teethers might leach EDCs that escape routine analysis and, thus, toxicological evaluation. The resulting uncertainty in product safety poses a problem to consumers, producers and regulators that remain to be resolved. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-05-18T07:27:48.753651-05:
      DOI: 10.1002/jat.3159
       
  • Acute and subchronic toxicity of 20  kHz and
           60  kHz magnetic fields in rats
    • Authors: Izumi Nishimura; Atsushi Oshima, Kazumoto Shibuya, Takashi Mitani, Tadashi Negishi
      Abstract: Despite increasing use of intermediate frequency (IF) magnetic fields (MFs) in occupational and domestic settings, scientific evidence necessary for health risk assessments of IF MF is insufficient. Male and female Crl:CD(SD) rats (12 per sex per group) were exposed to 20 kHz, 0.20 mT(root mean square, rms) or 60 kHz, 0.10 mT(rms) sinusoidal MFs for 22 h day−1 for 14 days (acute) or 13 weeks (subchronic). Experiments were duplicated for each frequency to ensure outcome reproducibility, and examinations were blinded for quality assurance. All rats survived without significant clinical signs until the end of experiments. Some changes in body weight between the MF‐exposed and control groups were observed over the course of exposure, although the directions of the changes were inconsistent and not statistically significant after subchronic exposure. There were significant differences between MF‐exposed and control groups in some organ weights and parameters in hematology and clinical chemistry, but these were minor in magnitude and not repeated in duplicate experiments. Histopathological findings reflecting toxicity were sporadic. Frequencies of other findings were similar to historic data in this rat strain, and findings had no specific relationship to changes in organ weight or parameters of hematology and clinical chemistry in each animal. The changes observed throughout this study were considered biologically isolated and were attributable to chance associations rather than to MF exposure. The results, in particular the histopathological evidence, indicate an absence of toxicity in IF MF‐exposed rats and do not support the hypothesis that IF MF exposure produces significant toxicity. Copyright © 2015. The
      Authors . Journal of Applied Toxicology Published by John Wiley & Sons Ltd.
      PubDate: 2015-05-17T23:57:37.168612-05:
      DOI: 10.1002/jat.3161
       
  • Silver nanoparticles affect the neural development of zebrafish embryos
    • Authors: Qi Xin; Jeanette M. Rotchell, Jinping Cheng, Jun Yi, Qiang Zhang
      Abstract: Silver nanoparticles (AgNPs) have been widely used in commercial products. This study aims to understand the impact of AgNPs on the early developmental stages in zebrafish (Danio rerio) embryos. Embryos were exposed to two sizes of AgNPs at three dose levels, as well to free Ag+ ions, for a range of 4–96 h post‐fertilization (hpf). The acute exposure study showed that exposure to AgNPs affected the neurological development, and the exposed embryos exhibited anomalies such as small head with hypoplastic hindbrain, small eye and cardiac defects. At the molecular level, AgNPs altered the expression profiles of neural development‐related genes (gfap, huC and ngn1), metal‐sensitive metallothioneins and ABCC genes in exposed embryos. The expression of AhR2 and Cyp1A, which are usually considered to mediate polycyclic aromatic hydrocarbon toxicity, were also significantly changed. A size‐dependent uptake of AgNPs was observed, whereby 4 nm AgNPs were more efficiently taken up compared with the 10 nm‐sized particles. Importantly, the head area accumulated AgNPs more efficiently than the trunk area of exposed zebrafish embryos. No free Ag+ ions, which can be potentially released from the AgNP solutions, were detected. This study suggests that AgNPs could affect the neural development of zebrafish embryos, and the toxicity of AgNPs may be partially attributed to the comparatively higher uptake in the head area. These results indicate the potential neurotoxicity of AgNPs and could be extended to other aquatic organisms. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-05-15T00:29:17.852587-05:
      DOI: 10.1002/jat.3164
       
  • Intracellular calcium levels as screening tool for nanoparticle toxicity
    • Abstract: The use of engineered nano‐sized materials led to revolutionary developments in many industrial applications and in the medical field. These materials, however, also may cause cytotoxicity. In addition to size, surface properties and shape were identified as relevant parameters for cell damage. Cell damage may occur as disruption of membrane integrity, induction of apoptosis and by organelle damage. Generation of oxidative stress may serve as an indicator for cytotoxicity. Effects occurring upon short contact of particles with cells, for instance in the systemic blood circulation, could be identified according to increases of intracellular [Ca2+] levels, which are caused by variety of toxic stimuli. Negatively charged, neutral and positively charged polystyrene particles of different sizes were used to study the role of size and surface properties on viability, membrane disruption, apoptosis, lysosome function, intracellular [Ca2+] levels and generation of oxidative stress. Silica particles served to test this hypothesis. Twenty nm polystyrene particles as well as 12 nm and 40 nm silica particles caused membrane damage and apoptosis with no preference of the surface charge. Only 20 nm plain and amine functionalized polystyrene particles cause oxidative stress and only the plain particles lysosomal damage. A potential role of surface charge was identified for 200 nm polystyrene particles, where only the amidine particles caused lysosomal damage. Increases in intracellular [Ca2+] levels and cytotoxicity after 24 h was often linked but determination of intracellular [Ca2+] levels could serve to characterize further the type of membrane damage. © 2015 The
      Authors . Journal of Applied Toxicology Published by John Wiley & Sons Ltd.
      PubDate: 2015-05-14T21:12:31.32087-05:0
      DOI: 10.1002/jat.3160
       
  • Toxicological effects of pet food ingredients on canine bone
           marrow‐derived mesenchymal stem cells and enterocyte‐like
           cells
    • Abstract: We developed an in vitro method to assess pet food ingredients safety. Canine bone marrow‐derived mesenchymal stem cells (BMSC) were differentiated into enterocyte‐like cells (ELC) to assess toxicity in cells representing similar patterns of exposure in vivo. The toxicological profile of clove leave oil, eugenol, guanosine monophosphate (GMP), GMP + inosine monophosphate, sorbose, ginger root extract, cinnamon bark oil, cinnamaldehyde, thyme oil, thymol and citric acid was assessed in BMSC and ELC. The LC50 for GMP + inosine monophosphate was 59.42 ± 0.90 and 56.7 ± 3.5 mg ml–1 for BMSC and ELC; 56.84 ± 0.95 and 53.66 ± 1.36 mg ml–1 for GMP; 0.02 ± 0.001 and 1.25 ± 0.47 mg ml–1 for citric acid; 0.077 ± 0.002 and 0.037 ± 0.01 mg ml–1 for cinnamaldehyde; 0.002 ± 0.0001 and 0.002 ± 0.0008 mg ml–1 for thymol; 0.080 ± 0.003 and 0.059 ± 0.001 mg ml–1 for thyme oil; 0.111 ± 0.002 and 0.054 ± 0.01 mg ml–1 for cinnamon bark oil; 0.119 ± 0.0004 and 0.099 ± 0.011 mg ml–1 for clove leave oil; 0.04 ± 0.001 and 0.028 ± 0.002 mg ml–1 for eugenol; 2.80 ± 0.11 and 1.75 ± 0.51 mg ml–1 for ginger root extract; > 200 and 116.78 ± 7.35 mg ml–1 for sorbose. Lemon grass oil was evaluated at 0.003–0.9 in BMSC and .03‐0.9 mg ml–1 in ELC and its mechanistic effect was investigated. The gene toxicology studies showed regulation of 61% genes in CYP450 pathway, 37% in cholestasis and 33% in immunotoxicity pathways for BMSC. For ELC, 80% for heat shock response, 69% for beta‐oxidation and 65% for mitochondrial energy metabolism. In conclusion, these studies provide a baseline against which differential toxicity of dietary feed ingredients can be assessed in vitro for direct effects on canine cells and demonstrate differential toxicity in differentiated cells that represent gastrointestinal epithelial cells. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-05-14T18:22:26.588619-05:
      DOI: 10.1002/jat.3158
       
  • Safety data on 19 vehicles for use in 1 month oral rodent
           pre‐clinical studies: administration of
           hydroxypropyl‐ß‐cyclodextrin causes renal toxicity
    • Authors: Guy Healing; Tabassum Sulemann, Peter Cotton, Jayne Harris, Adam Hargreaves, Rowena Finney, Sarah Kirk, Carolin Schramm, Clare Garner, Perrine Pivette, Lisa Burdett
      Abstract: Potential new drugs are assessed in pre‐clinical in vivo studies to determine their safety profiles. The drugs are formulated in vehicles suitable for the route of administration and the physicochemical properties of the drug, aiming to achieve optimal exposure in the test species. The availability of safety data on vehicles is often limited (incomplete data, access restricted/private databases). Nineteen potentially useful vehicles that contained new and/or increased concentrations of excipients and for which little safety data have been published were tested. Vehicles were dosed orally once daily to HanWistar rats for a minimum of 28 days and a wide range of toxicological parameters were assessed. Only 30% (w/v) hydroxypropyl‐ß‐cyclodextrin was found unsuitable owing to effects on liver enzymes (AST, ALT and GLDH), urinary volume and the kidneys (tubular vacuolation and tubular pigment). 20% (v/v) oleic acid caused increased salivation and hence this vehicle should be used with caution. As 40% (v/v) tetraethylene glycol affected urinary parameters, its use should be carefully considered, particularly for compounds suspected to impact the renal system and studies longer than 1 month. There were no toxicologically significant findings with 10% (v/v) dimethyl sulphoxide, 20% (v/v) propylene glycol, 33% (v/v) Miglyol®812, 20% (w/v) Kolliphor®RH40, 10% (w/v) Poloxamer 407, 5% (w/v) polyvinylpyrrolidone K30 or 10% (v/v) Labrafil®M1944. All other vehicles tested caused isolated or low magnitude effects which would not prevent their use. The aim of sharing these data, including adverse findings, is to provide meaningful information for vehicle selection, thereby avoiding repetition of animal experimentation. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-05-10T20:18:00.800754-05:
      DOI: 10.1002/jat.3155
       
  • Maternal exposure to hexachlorophene targets intermediate‐stage
           progenitor cells in the hippocampal neurogenesis involving myelin
           vacuolation of cholinergic and glutamatergic inputs in mice
    • Authors: Mizuho Kato; Hajime Abe, Megu Itahashi, Yoh Kikuchihara, Masayuki Kimura, Sayaka Mizukami, Toshinori Yoshida, Makoto Shibutani
      Abstract: Hexachlorophene (HCP) has been shown to induce myelin vacuolation due to intramyelinic edema of the nerve fibers in animal neural tissue. We investigated the maternal exposure effect of HCP on hippocampal neurogenesis in the offspring of pregnant mice supplemented with 0 (control), 33 or 100 ppm HCP in diet from gestational day 6 to day 21 after delivery. On postnatal day (PND) 21, offspring as examined in males exhibited decreased granule cell lineage populations expressing paired box 6, sex‐determining region Y‐box 2 and eomesodermin in the hippocampal subgranular zone (SGZ) accompanied by myelin vacuolation involving white matter tracts of the hippocampal fimbria at ≥ 33 ppm. However, SGZ cellular populations expressing brain lipid binding protein and doublecortin were unchanged at any dose. Transcript expression of cholinergic receptor genes, Chrna4 and Chrnb2, and glutamate receptor genes, Grm1 and Grin2d, examined at 100 ppm, decreased in the dentate gyrus. HCP exposure did not alter the number of proliferating or apoptotic cells in the SGZ, or reelin‐ or calcium‐binding protein‐expressing γ‐aminobutyric acid (GABA)ergic interneurons in the dentate hilus, on PND 21 and PND 77. All neurogenesis‐related changes observed in HCP‐exposed offspring on PND 21 disappeared on PND 77, suggesting that maternal HCP exposure at ≥ 33 ppm reversibly decreased type 2 intermediate‐stage progenitor cells in the hippocampal neurogenesis. Myelin vacuolation might be responsible for changes in neurogenesis possibly by reducing nerve conduction velocity of cholinergic inputs from the septal–hippocampal pathway to granule cell lineages and/or GABAergic interneurons, and of glutamatergic inputs to granule cell lineages. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-05-05T09:13:26.853194-05:
      DOI: 10.1002/jat.3162
       
  • mRNAs and miRNAs in whole blood associated with lung hyperplasia,
           fibrosis, and bronchiolo‐alveolar adenoma and adenocarcinoma after
           multi‐walled carbon nanotube inhalation exposure in mice
    • Abstract: Inhalation exposure to multi‐walled carbon nanotubes (MWCNT) in mice results in inflammation, fibrosis and the promotion of lung adenocarcinoma; however, the molecular basis behind these pathologies is unknown. This study determined global mRNA and miRNA profiles in whole blood from mice exposed by inhalation to MWCNT that correlated with the presence of lung hyperplasia, fibrosis, and bronchiolo‐alveolar adenoma and adenocarcinoma. Six‐week‐old, male, B6C3F1 mice received a single intraperitoneal injection of either the DNA‐damaging agent methylcholanthrene (MCA, 10 µg g−1 body weight) or vehicle (corn oil). One week after injections, mice were exposed by inhalation to MWCNT (5 mg m−3, 5 hours per day, 5 days per week) or filtered air (control) for a total of 15 days. At 17 months post‐exposure, mice were euthanized and examined for the development of pathological changes in the lung, and whole blood was collected and analyzed using microarray analysis for global mRNA and miRNA expression. Numerous mRNAs and miRNAs in the blood were significantly up‐ or down‐regulated in animals developing pathological changes in the lung after MCA/corn oil administration followed by MWCNT/air inhalation, including fcrl5 and miR‐122‐5p in the presence of hyperplasia, mthfd2 and miR‐206‐3p in the presence of fibrosis, fam178a and miR‐130a‐3p in the presence of bronchiolo‐alveolar adenoma, and il7r and miR‐210‐3p in the presence of bronchiolo‐alveolar adenocarcinoma, among others. The changes in miRNA and mRNA expression, and their respective regulatory networks, identified in this study may potentially serve as blood biomarkers for MWCNT‐induced lung pathological changes. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-04-29T23:36:08.828959-05:
      DOI: 10.1002/jat.3157
       
  • In vitro neurotoxicity evaluation of piperazine designer drugs in
           differentiated human neuroblastoma SH‐SY5Y cells
    • Authors: M. D. Arbo; R. Silva, D. J. Barbosa, D. Dias Silva, S. P. Silva, J. P. Teixeira, M. L. Bastos, H. Carmo
      Abstract: Abuse of synthetic drugs is widespread worldwide. Studies indicate that piperazine designer drugs act as substrates at dopaminergic and serotonergic receptors and/or transporters in the brain. This work aimed to investigate the cytotoxicity of N‐benzylpiperazine, 1‐(3‐trifluoromethylphenyl)piperazine, 1‐(4‐methoxyphenyl)piperazine and 1‐(3,4‐methylenedioxybenzyl)piperazine in the differentiated human neuroblastoma SH‐SY5Y cell line. Cytotoxicity was evaluated after 24 h incubations through the MTT reduction and neutral red uptake assays. Oxidative stress (reactive oxygen and nitrogen species production and glutathione content) and energetic (ATP content) parameters, as well as intracellular Ca2+, mitochondrial membrane potential, DNA damage (comet assay) and cell death mode were also evaluated. Complete cytotoxicity curves were obtained after 24 h incubations with each drug. A significant decrease in intracellular total glutathione content was noted for all the tested drugs. All drugs caused a significant increase of intracellular free Ca2+ levels, accompanied by mitochondrial hyperpolarization. However, ATP levels remained unchanged. The investigation of cell death mode revealed a predominance of early apoptotic cells. No genotoxicity was found in the comet assay. Among the tested drugs, 1‐(3‐trifluoromethylphenyl)piperazine was the most cytotoxic. Overall, piperazine designer drugs are potentially neurotoxic, supporting concerns on risks associated with the abuse of these drugs. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-04-20T20:48:22.46823-05:0
      DOI: 10.1002/jat.3153
       
  • In vitro study of biocompatibility of a graphene composite with gold
           nanoparticles and hydroxyapatite on human osteoblasts
    • Authors: Liana Crisan; Bogdan Crisan, Olga Soritau, Mihaela Baciut, Alexandru Radu Biris, Grigore Baciut, Ondine Lucaciu
      Abstract: The purpose of this study was to evaluate the biocompatibility of some composites consisting of different proportions of graphene in combination with gold nanoparticles (AuNPs) and nanostructured hydroxyapatite (HA) on osteoblast viability, proliferation and differentiation. Au/HA@graphene composites synthesized by the catalytic chemical vapor deposition induction heating method with acetylene as the carbon source and over an Au/HA catalyst, were characterized by transmission electron microscopy, thermogravimetric analysis and Raman spectroscopy and showed that the few‐layer graphene was grown over the Au/HA catalyst. The cytocompatibility study was performed using the fluorescein diacetate assay for assessment of the viability and proliferation of osteoblasts cultivated in the presence of HA, Au/HA and Au/HA@graphene composites as colloidal suspensions or as substrates. The most favorable composites for cell adhesion and proliferation were HA, Au/HA and Au/HA composites with 1.6% and 3.15% concentration of graphenes. Immunocytochemical staining performed after 19 days of osteoblasts cultivation on substrates showed that the graphene composites induced low expression of alkaline phosphatase compared to the control group and HA and Au/HA substrates. The presence of graphene in the substrate composition also induced an increased level of intracellular osteopontin and cytoskeleton reorganization (actin‐F) depending on graphene concentration, suggesting cell activation, increased cellular adhesion and acquisition of a mechanosensorial osteocyte phenotype. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-04-20T20:15:45.376371-05:
      DOI: 10.1002/jat.3152
       
  • Preclinical safety evaluation of low molecular weight
           heparin–deoxycholate conjugates as an oral anticoagulant
    • Abstract: The preclinical safety of a newly developed oral anticoagulant, the low molecular weight heparin–deoxycholate conjugate (OH09208), was evaluated by a comprehensive evaluating program in compliance with standard guidelines. The single dose oral toxicity study in rats receiving 2000 and 5000 mg kg−1 of OH09208 did not reveal any mortality, unusual body weight changes or necropsy findings. The results of the 4‐week oral toxicity study with a 4‐week recovery program in rats receiving OH09208 in doses of 100, 300 and 1000 mg kg−1 day−1 did not reveal any mortality, or indicate any unusual clinical signs, or show any toxicokinetic relationships to the administration of OH09208. Although the increase in liver enzymes in one male dog treated with 300 mg kg−1 day−1 and one female dog treated with 1000 mg kg−1 day−1 could not be excluded from the effect of the test substance, no other toxicologically significant changes were observed in the 4‐week oral toxicity study with a 4‐week recovery in beagle dogs. Thus, while the no‐observed‐adverse‐effect level value from the 4‐week study in both male and female rats was 1000 mg kg−1 day−1, those from the 4‐week study in male and female beagle dogs were 300 and 1000 mg kg−1 day−1, respectively. Furthermore, OH09208 did not induce anaphylactic reactions in guinea pigs, micronucleated bone marrow cells in male ICR mice, chromosomal aberration in Chinese hamster lung cell lines, bacterial reverse mutation, and any abnormalities in hERG current assay, mouse central nervous system and dog cardiovascular studies. Overall, there were no unexpected toxicities in this preclinical study that might have precluded the safe administration of OH09208 to humans. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-04-20T19:26:21.800263-05:
      DOI: 10.1002/jat.3146
       
  • Establishment of a mouse model for amiodarone‐induced liver injury
           and analyses of its hepatotoxic mechanism
    • Authors: Shohei Takai; Shingo Oda, Koichi Tsuneyama, Tatsuki Fukami, Miki Nakajima, Tsuyoshi Yokoi
      Abstract: Drug‐induced liver injury (DILI) is the most frequent cause of post‐marketing warnings and withdrawals. Amiodarone (AMD), an antiarrhythmic, presents a risk of liver injury in humans, and its metabolites, formed by cytochrome P450 3A4, are likely more toxic to hepatocytes than AMD is. However, it remains to be clarified whether the metabolic activation of AMD is involved in liver injury in vivo. In this study, to elucidate the underlying mechanisms of AMD‐induced liver injury, mice were administered AMD [1000 mg kg–1, per os (p.o.)] after pretreatment with dexamethasone [DEX, 60 mg kg–1, intraperitoneal (i.p.)], which induces P450 expression, once daily for 3 days. The plasma alanine aminotransferase (ALT) levels were significantly increased by AMD administration in the DEX‐pretreated mice, and the liver concentrations of desethylamiodarone (DEA), a major metabolite of AMD, were correlated with the changes in the plasma ALT levels. Cytochrome c release into the hepatic cytosol and triglyceride levels in the plasma were increased in DEX plus AMD‐administered mice. Furthermore, the ratio of reduced glutathione to oxidized glutathione disulfide in the liver significantly decreased in the DEX plus AMD‐administered mice. The increase of ALT levels was suppressed by treatment with gadolinium chloride (GdCl3), which is an inhibitor of Kupffer cell function. From these results, it is suggested that AMD and/or DEA contribute to the pathogenesis of AMD‐induced liver injury by producing mitochondrial and oxidative stress and Kupffer cell activation. This study proposes the mechanisms of AMD‐induced liver injury using an in vivo mouse model. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-04-20T19:19:47.146916-05:
      DOI: 10.1002/jat.3141
       
  • Bisphenol A inhibits duodenal movement ex vivo of rat through nitric
           oxide‐mediated soluble guanylyl cyclase and α‐adrenergic
           signaling pathways
    • Authors: Kaushik Sarkar; Panchali Tarafder, Goutam Paul
      Abstract: The gastrointestinal tract is directly exposed to bisphenol A (BPA)‐tainted foods and beverages stored in polycarbonate plastic containers. The effect of BPA on the movement of small intestine has not been reported until now. We report here the effect of BPA on the movement of the duodenum ex vivo in a rat model. We found significant inhibition of duodenal movement by BPA (10–320 µ M). We suggest that BPA‐induced inhibition of duodenal movement might be due to the suppression of stimulatory and/or activation of inhibitory motor neurons in enteric plexuses innervating the longitudinal and circular visceral smooth muscle cells in the duodenal wall. We observed a significant reversal of BPA‐induced depression of duodenal movement by methylene blue, a soluble guanylyl cyclase blocker and N‐ω‐nitro‐ L‐arginine methyl ester, a nitric oxide (NO) synthase inhibitor; but significant potentiation of the movement by sodium nitroprusside, a NO donor. From the results, we may suggest that BPA‐induced inhibition of the movement might be partially due to activation of inhibitory motor neurons that secrete NO, a relaxant, on to smooth muscle cells. Furthermore, we found significant reversal of BPA‐induced depression of the movement in phentolamine, an α‐adrenergic receptor blocker, pretreated preparation. This result proves that norepinephrine secreting motor neurons may also be involved in BPA‐induced inhibition of the movement. From the results, we conclude that BPA inhibits the movement of the duodenum through NO‐mediated soluble guanylyl cyclase and α‐adrenergic signaling pathways in visceral smooth muscle cells. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-04-16T05:40:57.910581-05:
      DOI: 10.1002/jat.3154
       
  • Human ketosteroid receptors interact with hazardous phthalate plasticizers
           and their metabolites: an in silico study
    • Abstract: Phthalic acid esters or phthalates are ubiquitous environmental pollutants known for their adverse health effects in test animals and, of late, in humans. Thus, in this molecular docking study – using Glide (Schrödinger) – the molecular interactions of 31 ligands, including 12 diphthalates, their monophthalates and phthalic acid with selected human ketosteroid receptors, i.e., androgen (hAR), progesterone (hPR) and glucocorticoid (hGR) receptors were explored and their binding affinities were compared with that of corresponding natural steroids and a known endocrine disrupting xenobiotic, bisphenol A (BPA). Mostly, diphthalates and monophthalates showed the potential for antisteroidal activity by interacting with hAR, hPR and hGR. Of them, diphenyl phthalate showed the highest G score (–7.70 kcal mol–1) with hAR, and the crucial amino acid (aa) residues in the ligand binding domain (LBD) of this receptor involved in the molecular interactions were Phe 764, Leu 704, Asn 705 and Thr 877. The mono‐iso‐decyl phthalate showed the highest G score (–8.36) with the hPR, and the crucial aa residues in the LBD interactions were Arg 766 Gln 725 and Phe 778. The mono‐iso‐decyl phthalate also showed more affinity (–8.44) towards hGR than the natural ligand, and the aa residues in the LBD interactions were Gln 570 and Met 604. In addition to these, some other phthalates established comparable interactions with certain aa residues located in the LBD of these receptors, which resulted in higher G scores. Contrastingly, BPA and some natural ligands tested in this study showed lower G scores with these receptors than certain phthalates reported herein, i.e., certain phthalates are more toxic than the proven toxic BPA. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • The toxic effects of indoor atmospheric fine particulate matter collected
           from allergic and non‐allergic families in Wuhan on mouse peritoneal
           macrophages
    • Abstract: Recent studies have shown that fine particulate matter (PM2.5) is associated with multiple adverse health outcomes and PM2.5‐induced oxidative stress is now commonly known as a proposed mechanism of PM2.5‐mediated toxicity. However, the association between allergic symptoms in children and exposure to PM2.5 has not been fully elucidated, particularly the role of PM2.5 on the indoor environment involved in allergy or non‐allergy is unknown. The aim of the present study was to explore whether indoor PM2.5 from the homes of children with allergic symptoms had more increased risks of allergy than that of healthy ones and then compare the toxicity and inflammatory response of them. In this study, indoor PM2.5 was collected from the homes of schoolchildren with allergic symptoms and those of healthy ones respectively, and components of PM2.5 were analyzed. PM2.5‐mediated oxidative damage and inflammatory response were further evaluated in mouse peritoneal macrophages based on its effects on the levels of reactive oxygen species accumulation, lipid peroxidation, DNA damage or cytokine production. It seems that oxidative stress may contribute to PM2.5‐induced toxicity, and PM2.5 from the allergic indoor environment produced more serious toxic effects and an inflammatory response on mouse peritoneal macrophages than that from a non‐allergic indoor environment. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • The impact of caffeine on connexin expression in the embryonic chick
           cardiomyocyte micromass culture system
    • Abstract: Cardiomyocytes are electrically coupled by gap junctions, defined as clusters of low‐resistance multisubunit transmembrane channels composed of connexins (Cxs). The expression of Cx40, Cx43 and Cx45, which are present in cardiomyocytes, is known to be developmentally regulated. This study investigates the premise that alterations in gap junction proteins are one of the mechanisms by which teratogens may act. Specifically, those molecules known to be teratogenic in humans could cause their effects via disruption of cell‐to‐cell communication pathways, resulting in an inability to co‐ordinate tissue development. Caffeine significantly inhibited contractile activity at concentrations above and including 1500 μm (P < 0.05), while not affecting cell viability and total protein, in the embryonic chick cardiomyocyte micromass culture system. The effects of caffeine on key cardiac gap junction protein (Cx40, Cx43 and Cx45) expression were analysed using immunocytochemistry and in‐cell Western blotting. The results indicated that caffeine altered the expression pattern of Cx40, Cx43 and Cx45 at non‐cytotoxic concentrations (≥2000 μm), i.e., at concentrations that did not affect total cell protein and cell viability. In addition the effects of caffeine on cardiomyocyte formation and function (contractile activity score) were correlated with modulation of Cxs (Cx40, Cx43 and Cx45) expression, at above and including 2000 μm caffeine concentrations (P < 0.05). These experiments provide evidence that embryonic chick cardiomyocyte micromass culture may be a useful in vitro method for mechanistic studies of perturbation of embryonic heart development. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • The surfactant dipalmitoylphophatidylcholine modifies acute responses in
           alveolar carcinoma cells in response to low‐dose silver nanoparticle
           exposure
    • Abstract: Nanotechnology is a rapidly growing field with silver nanoparticles (AgNP) in particular utilized in a wide variety of consumer products. This has presented a number of concerns relating to exposure and the associated toxicity to humans and the environment. As inhalation is the most common exposure route, this study investigates the potential toxicity of AgNP to A549 alveolar epithelial carcinoma cells and the influence of a major component of lung surfactant dipalmitoylphosphatidylcholine (DPPC) on toxicity. It was illustrated that exposure to AgNP generated low levels of oxidative stress and a reduction in cell viability. While DPPC produced no significant effect on viability studies its presence resulted in increased reactive oxygen species formation. DPPC also significantly modified the inflammatory response generated by AgNP exposure. These findings suggest a possible interaction between AgNP and DPPC causing particles to become more reactive, thus increasing oxidative insult and inflammatory response within A549 cells. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Aluminium oxide nanoparticles induced morphological changes, cytotoxicity
           and oxidative stress in Chinook salmon (CHSE‐214) cells
    • Abstract: Aluminium oxide nanoparticles (Al2O3 NPs) are increasingly used in diverse applications that has raised concern about their safety. Recent studies suggested that Al2O3 NPs induced oxidative stress may be the cause of toxicity in algae, Ceriodaphnia dubia, Caenorhabditis elegans and Danio rerio. However, there is paucity on the toxicity of Al2O3 NPs on fish cell lines. The current study was aimed to investigate Al2O3 NPs induced cytotoxicity, oxidative stress and morphological abnormality of Chinnok salmon cells (CHSE‐214). A dose‐dependent decline in cell viability was observed in CHSE‐214 cells exposed to Al2O3 NPs. Oxidative stress induced by Al2O3 NPs in CHSE‐214 cells has resulted in the significant reduction of superoxide dismutase, catalase and glutathione in a dose‐dependent manner. However, a significant increase in glutathione sulfo‐transferase and lipid peroxidation was observed in CHSE‐214 cells exposed to Al2O3 NPs in a dose‐dependent manner. Significant morphological changes in CHSE‐214 cells were observed when exposed to Al2O3 NPs at 6, 12 and 24 h. The cells started to detach and appear spherical at 6 h followed by loss of cellular contents resulting in the shrinking of the cells. At 24 h, the cells started to disintegrate and resulted in cell death. Our data demonstrate that Al2O3 NPs induce cytotoxicity and oxidative stress in a dose‐dependent manner in CHSE‐214 cells. Thus, our current work may serve as a base‐line study for future evaluation of toxicity studies using CHSE‐214 cells. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Titanium dioxide nanoparticles increase plasma glucose via reactive oxygen
           species‐induced insulin resistance in mice
    • Abstract: There have been few reports about the possible toxic effects of titanium dioxide (TiO2) nanoparticles on the endocrine system. We explored the endocrine effects of oral administration to mice of anatase TiO2 nanoparticles (0, 64 and 320 mg kg–1 body weight per day to control, low‐dose and high‐dose groups, respectively, 7 days per week for 14 weeks). TiO2 nanoparticles were characterized by scanning and transmission electron microscopy (TEM) and dynamic light scattering (DLS), and their physiological distribution was investigated by inductively coupled plasma. Biochemical analyzes included plasma glucose, insulin, heart blood triglycerides (TG), free fatty acid (FFA), low‐density lipoprotein cholesterol (LDL‐C), high‐density lipoprotein cholesterol (HDL‐C), total cholesterol (TC), tumor necrosis factor‐alpha (TNF‐α), interleukin (IL)‐6 and reactive oxygen species (ROS)‐related markers (total SOD, GSH and MDA). Phosphorylation of IRS1, Akt, JNK1, and p38 MAPK were analyzed by western blotting. Increased titanium levels were found in the liver, spleen, small intestine, kidney and pancreas. Biochemical analyzes showed that plasma glucose significantly increased whereas there was no difference in plasma insulin secretion. Increased ROS levels were found in serum and the liver, as evidenced by reduced total SOD activity and GSH level and increased MDA content. Western blotting showed that oral administration of TiO2 nanoparticles induced insulin resistance (IR) in mouse liver, shown by increased phosphorylation of IRS1 (Ser307) and reduced phosphorylation of Akt (Ser473). The pathway by which TiO2 nanoparticles increase ROS‐induced IR were included in the inflammatory response and phosphokinase, as shown by increased serum levels of TNF‐α and IL‐6 and increased phosphorylation of JNK1 and p38 MAPK in liver. These results show that oral administration of TiO2 nanoparticles increases ROS, resulting in IR and increasing plasma glucose in mice. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Particle uptake efficiency is significantly affected by type of capping
           agent and cell line
    • Abstract: Surface‐functionalized silver nanoparticles (AgNPs) are the most deployed engineered nanomaterials in consumer products because of their optical, antibacterial and electrical properties. Almost all engineered nanoparticles are coated with application‐specific capping agents (i.e. organic/inorganic ligands on particle surface) to enhance their stability in suspension or increase their biocompatibility for biomedicine. The aim of this study was to investigate the contribution of the selected capping agents to their observed health impacts using realistic dose ranges. AgNPs capped with citrate, polyvinylpyrrolidone (PVP) and tannic acid were studied with human bronchoalveolar carcinoma (A549) and human colon adenocarcinoma (Caco‐2) cell lines and compared against exposures to Ag ions. Cellular uptake and cytotoxicity were evaluated up to 24 h. Tannic acid capped AgNPs induced higher cellular uptake and rate in both cell lines. Citrate‐capped and PVP‐capped AgNPs behaved similarly over 24 h. All three of the capped AgNPs penetrated more into the A549 cells than Caco‐2 cells. In contrast, the uptake rate of Ag ions in Caco‐2 cells (0.11 ± 0.0001 µg h–1) was higher than A549 cells (0.025 ± 0.00004 µg h–1). The exposure concentration of 3 mg l–1 is below the EC50 value for all of the AgNPs; therefore, little cytotoxicity was observed in any experiment conducted herein. Exposure of Ag ions, however, interrupted cell membrane integrity and cell proliferation (up to 70% lysed after 24 h). These findings indicate cellular uptake is dependent on capping agent, and when controlled to realistic exposure concentrations, cellular function is not significantly affected by AgNP exposure. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Investigation on cobalt‐oxide nanoparticles cyto‐genotoxicity
           and inflammatory response in two types of respiratory cells
    • Abstract: The increasing use of cobalt oxide (Co3O4) nanoparticles (NPs) in several applications and the suggested genotoxic potential of Co‐oxide highlight the importance of evaluating Co3O4 NPs toxicity. Cyto‐genotoxic and inflammatory effects induced by Co3O4 NPs were investigated in human alveolar (A549), and bronchial (BEAS‐2B) cells exposed to 1–40 µg ml–1. The physicochemical properties of tested NPs were analysed by transmission electron microscopy (TEM) and dynamic light scattering (DLS). Cytotoxicity was studied to analyze cell viability (WST1 test) and membrane damage (LDH assay), direct/oxidative DNA damage was assessed by the Formamido‐pyrimidine glycosylase (Fpg)‐modified comet assay and inflammation by interleukin (IL)‐6, IL‐8 and tumor necrosis factor‐alpha (TNF‐α) release (ELISA). In A549 cells, no cytotoxicity was found, whereas BEAS‐2B cells showed a viability reduction at 40 µg ml–1 and early membrane damage at 1, 5 and 40 µg ml–1. In A549 cells, direct and oxidative DNA damage at 20 and 40 µg ml–1 were detected without any effects on cytokine release. In BEAS‐2B cells, significant direct DNA damage at 40 µg ml–1 and significant oxidative DNA damage with a peak at 5 µg ml–1, that was associated with increased TNF‐α release at 1 µg ml–1 after 2 h and increased IL‐8 release at 20 µg ml–1 after 24 h, were detected. The findings show in the transformed alveolar cells no cytotoxicity and genotoxic/oxidative effects at 20 and 40 µg ml–1. In normal bronchial cells, moderate cytotoxicity, direct DNA damage only at the highest concentration and significant oxidative‐inflammatory effects at lower concentrations were detected. The findings confirm the genotoxic‐oxidative potential of Co3O4 NPs and show greater sensitivity of BEAS‐2B cells to cytotoxic and oxidative‐inflammatory effects suggesting the use of different cell lines and multiple end‐points to elucidate Co3O4 NPs toxicity. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Particulate matter phagocytosis induces tissue factor in differentiating
           macrophages
    • Abstract: Airborne exposure to particulate matter with diameter
       
  • PM2.5‐induced oxidative stress increases adhesion molecules
           expression in human endothelial cells through the
           ERK/AKT/NF‐κB‐dependent pathway
    • Abstract: The aim of this study was to explore the intracellular mechanisms underlying the cardiovascular toxicity of air particulate matter (PM) with an aerodynamic diameter of less than 2.5 µm (PM2.5) in a human umbilical vein cell line, EA.hy926. We found that PM2.5 exposure triggered reactive oxygen species (ROS) generation, resulting in a significant decrease in cell viability. Data from Western blots showed that PM2.5 induced phosphorylation of Jun N‐terminal kinase (JNK), extracellular signal regulatory kinase (ERK), p38 mitogen‐activated protein kinase (MAPK) and protein kinase B (AKT), and activation of nuclear factor kappa B (NF‐κB). We further observed a significant increase in expressions of intercellular adhesion molecule‐1 (ICAM‐1) and vascular adhesion molecule‐1 (VCAM‐1) in a time‐ and dose‐dependent manner. Moreover, the adhesion of monocytic THP‐1 cells to EA.hy926 cells was greatly enhanced in the presence of PM2.5. However, N‐acetylcysteine (NAC), a scavenger of ROS, prevented the increase of ROS generation, attenuated the phosphorylation of the above kinases, and decreased the NF‐κB activation as well as the expression of ICAM‐1 and VCAM‐1. Furthermore, ERK inhibitor (U0126), AKT inhibitor (LY294002) and NF‐κB inhibitor (BAY11‐7082) significantly down‐regulated PM2.5‐induced ICAM‐1 and VCAM‐1 expression as well as adhesion of THP‐1 cells, but not JNK inhibitor (SP600125) and p38 MAPK inhibitor (SB203580), indicating that ERK/AKT/NF‐κB is involved in the signaling pathway that leads to PM2.5‐induced ICAM‐1 and VCAM‐1 expression. These findings suggest PM2.5‐induced ROS may function as signaling molecules triggering ICAM‐1 and VCAM‐1 expressions through activating the ERK/AKT/NF‐κB‐dependent pathway, and further promoting monocyte adhesion to endothelial cells. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Acrylamide induces locomotor defects and degeneration of dopamine neurons
           in Caenorhabditis elegans
    • Abstract: Acrylamide can form in foods during the cooking process and cause multiple adverse effects. However, the neurotoxicity and mechanisms of acrylamide have not been fully elucidated. In Caenorhabditis elegans, we showed that 48 h exposure to 10–625 mg l−1 acrylamide resulted in a significant decline in locomotor frequency of body bending, head thrashing and pharynx pumping. In addition, acrylamide exposure reduced crawling speeds and changed angles of body bending. It indicates that acrylamide induces locomotor defects, along with parkinsonian‐like movement impairment, including bradykinesia and hypokinesia. Acrylamide also affected chemotaxis plasticity and reduced learning ability. Using transgenic nematodes, we found that acrylamide induced downexpression of Pdat‐1 and led to the degeneration of dopaminergic neurons. Moreover, the enhanced expression of unc‐54, encoding a subunit of α‐synuclein was found. It illustrates that acrylamide is efficient in inducing crucial parkinsonian pathology, including dopaminergic damage and α‐synuclein aggregation. These findings suggest the acrylamide‐induced locomotor defects and neurotoxicity are associated with Parkinson's disease. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Microminipigs as a new experimental animal model for toxicological
           studies: comparative pharmacokinetics of perfluoroalkyl acids
    • Abstract: In this study, we evaluated the efficacy of a novel minipig strain, the Microminipig (MMPig), as an animal model for studying the pharmacokinetics of a mixture of 10 perfluoroalkyl acids (PFAAs). After a single oral dose was given, we found that the blood depuration of PFAAs (blood t1/2), which we calculated using first‐order elimination curves, ranged from 1.6 to 86.6 days. Among the five body compartments analyzed, the liver was the greatest site of accumulation of perfluorooctanesulfonate and longer chain perfluorinated carboxylates such as perfluorodecanoic acid, perfluoroundecanoic acid and perfluorododecanoic acid. We observed an increasing accumulation trend of perfluorinated carboxylates in the organs associated with the fluorinated carbon chain length. The perfluorononanoic acid burden was the highest among the treated compounds 21 days after a single exposure, as 29% of the given perfluorononanoic acid dose was accumulated in the tissues. The persistence of PFAAs in edible pig tissues even after 21 days post‐exposure raises concerns about the safety of swine products. This was the first study to use MMPigs to elucidate the pharmacokinetics of a group of environmental pollutants. We found that MMPigs could be excellent experimental animals for toxicological studies due to their easy handling, cost efficacy for target compounds and ease of waste treatment. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Aryl hydrocarbon receptor knockout rats are insensitive to the
           pathological effects of repeated oral exposure to
           2,3,7,8‐tetrachlorodibenzo‐p‐dioxin
    • Abstract: Sustained activation of the aryl hydrocarbon receptor (AHR) is believed to be the initial key event in AHR receptor‐mediated tumorigenesis in the rat liver. The role of AHR in mediating pathological changes in the liver prior to tumor formation was investigated in a 4‐week, repeated‐dose study using adult female wild‐type (WT) and AHR knockout (AHR‐KO) rats treated with 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD). Beginning at 8 weeks of age, AHR‐KO and WT rats were dosed by oral gavage with varying concentrations of TCDD (0, 3, 22, 100, 300 and 1000 ng kg−1 day−1). Lung, liver and thymus histopathology, hematology, serum chemistry and the distribution of TCDD in liver and adipose tissue were examined. Treatment‐related increases in the severity of liver and thymus pathology were observed in WT, but not AHR‐KO rats. In the liver, these included hepatocellular hypertrophy, bile duct hyperplasia, multinucleated hepatocytes and inflammatory cell foci. A loss of cellularity in the thymic cortex and thymic atrophy was observed. Treatment‐related changes in serum chemistry parameters were also observed in WT, but not AHR‐KO rats. Finally, dose‐dependent accumulation of TCDD was observed primarily in the liver of WT rats and primarily in the adipose tissue of AHR‐KO rats. The results suggest that AHR activation is the initial key event underlying the progression of histological effects leading to liver tumorigenesis following TCDD treatment. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Sensitive periods for 17β‐estradiol exposure during immune
           system development in sea bass head kidney
    • Abstract: An increasing body of evidence suggests that sex steroids play an important role in the development and regulation of vertebrate immune defense. Therefore, compounds with estrogenic activity may influence the immune system via receptor‐mediated pathways. The presence of estrogen receptors in immune cells and organs during the early stages of development may indicate that female steroid hormones are involved in the maturation of the fish immune system. This is of particular importance, as some marine fish are probably exposed to sources of exogenous estrogens while they reside in their estuarine nursery grounds. In this study, the influence of 17β‐estradiol (E2) on estrogen receptor and cytokine gene expression was assessed in juvenile sea bass (Dicentrarchus labrax) together with characterization of the head kidney leukocyte populations and corresponding phagocytic activity during organ regionalization from 98 to 239 dph. E2 exposure, beginning at 90 dph resulted in indirect and delayed modifications of interleukin 1β and estrogen receptor α gene expression, which may affect B‐lymphocyte proliferation in the sea bass head kidney. The E2 treatment of 120 dph fish led to an increase in estrogen receptor β2 and a decrease in transforming growth factor β1 gene expression, which coincided with decreased phagocytic activity of head kidney lymphocytes and monocytes/macrophages. Additionally, these changes were observed during developmental periods described as critical phases for B‐lymphocyte development in mammals. Consequently, exogenous estrogens have the potential to modify the innate immune response in juvenile sea bass and to exert detrimental effects on head kidney development. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • An in vitro human skin test for assessing sensitization potential
    • Abstract: Sensitization to chemicals resulting in an allergy is an important health issue. The current gold‐standard method for identification and characterization of skin‐sensitizing chemicals was the mouse local lymph node assay (LLNA). However, for a number of reasons there has been an increasing imperative to develop alternative approaches to hazard identification that do not require the use of animals. Here we describe a human in‐vitro skin explant test for identification of sensitization hazards and the assessment of relative skin sensitizing potency. This method measures histological damage in human skin as a readout of the immune response induced by the test material. Using this approach we have measured responses to 44 chemicals including skin sensitizers, pre/pro‐haptens, respiratory sensitizers, non‐sensitizing chemicals (including skin‐irritants) and previously misclassified compounds. Based on comparisons with the LLNA, the skin explant test gave 95% specificity, 95% sensitivity, 95% concordance with a correlation coefficient of 0.9. The same specificity and sensitivity were achieved for comparison of results with published human sensitization data with a correlation coefficient of 0.91. The test also successfully identified nickel sulphate as a human skin sensitizer, which was misclassified as negative in the LLNA. In addition, sensitizers and non‐sensitizers identified as positive or negative by the skin explant test have induced high/low T cell proliferation and IFNγ production, respectively. Collectively, the data suggests the human in‐vitro skin explant test could provide the basis for a novel approach for characterization of the sensitizing activity as a first step in the risk assessment process. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Perfluorinated chemicals, PFOS and PFOA, enhance the estrogenic effects of
           17β‐estradiol in T47D human breast cancer cells
    • Abstract: Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are the two most popular surfactants among perfluorinated compounds (PFCs), with a wide range of uses. Growing evidence suggests that PFCs have the potential to interfere with estrogen homeostasis, posing a risk of endocrine‐disrupting effects. This in vitro study aimed to investigate the estrogenic effect of these compounds on T47D hormone‐dependent breast cancer cells. PFOS and PFOA (10−12 to 10−4 M) were not able to induce estrogen response element (ERE) activation in the ERE luciferase reporter assay. The ERE activation was induced when the cells were co‐incubated with PFOS (10−10 to 10−7 M) or PFOA (10−9 to 10−7 M) and 1 nM of 17β‐estradiol (E2). PFOS and PFOA did not modulate the expression of estrogen‐responsive genes, including progesterone (PR) and trefoil factor (pS2), but these compounds enhanced the effect of E2‐induced pS2 gene expression. Neither PFOS nor PFOA affected T47D cell viability at any of the tested concentrations. In contrast, co‐exposure with PFOS or PFOA and E2 resulted in an increase of E2‐induced cell viability, but no effect was found with 10 ng ml−1 EGF co‐exposure. Both compounds also intensified E2‐dependent growth in the proliferation assay. ERK1/2 phosphorylation was increased by co‐exposure with PFOS or PFOA and E2, but not with EGF. Collectively, this study shows that PFOS and PFOA did not possess estrogenic activity, but they enhanced the effects of E2 on estrogen‐responsive gene expression, ERK1/2 activation and the growth of the hormone‐deprived T47D cells. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • In vitro cytotoxicity of superparamagnetic iron oxide nanoparticles on
           neuronal and glial cells. Evaluation of nanoparticle interference with
           viability tests
    • Abstract: Superparamagnetic iron oxide nanoparticles (ION) have attracted great interest for use in several biomedical fields. In general, they are considered biocompatible, but little is known of their effects on the human nervous system. The main objective of this work was to evaluate the cytotoxicity of two ION (magnetite), coated with silica and oleic acid, previously determining the possible interference of the ION with the methodological procedures to assure the reliability of the results obtained. Human neuroblastoma SHSY5Y and glioblastoma A172 cells were exposed to different concentrations of ION (5–300 µg ml–1), prepared in complete and serum‐free cell culture medium for three exposure times (3, 6 and 24 h). Cytotoxicity was evaluated by means of the MTT, neutral red uptake and alamar blue assays. Characterization of the main physical–chemical properties of the ION tested was also performed. Results demonstrated that both ION could significantly alter absorbance readings. To reduce these interferences, protocols were modified by introducing additional washing steps and cell‐free systems. Significant decreases in cell viability were observed for both cell lines in specific conditions by all assays. In general, oleic acid‐coated ION were less cytotoxic than silica‐coated ION; besides, a serum‐protective effect was observed for both ION studied and cell lines. These results contribute to increase the knowledge of the potential harmful effects of ION on the human nervous system. Understanding these effects is essential to establish satisfactory regulatory policies on the safe use of magnetite nanoparticles in biomedical applications. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Antimicrobial agent triclosan is a proton ionophore uncoupler of
           mitochondria in living rat and human mast cells and in primary human
           keratinocytes
    • Abstract: Triclosan (TCS) is an antimicrobial used widely in hospitals and personal care products, at ~10 mm. Human skin efficiently absorbs TCS. Mast cells are ubiquitous key players both in physiological processes and in disease, including asthma, cancer and autism. We previously showed that non‐cytotoxic levels of TCS inhibit degranulation, the release of histamine and other mediators, from rat basophilic leukemia mast cells (RBL‐2H3), and in this study, we replicate this finding in human mast cells (HMC‐1.2). Our investigation into the molecular mechanisms underlying this effect led to the discovery that TCS disrupts adenosine triphosphate (ATP) production in RBL‐2H3 cells in glucose‐free, galactose‐containing media (95% confidence interval EC50 = 7.5–9.7 µm), without causing cytotoxicity. Using these same glucose‐free conditions, 15 µm TCS dampens RBL‐2H3 degranulation by 40%. The same ATP disruption was found with human HMC‐1.2 cells (EC50 4.2–13.7 µm), NIH‐3 T3 mouse fibroblasts (EC50 4.8–7.4 µm) and primary human keratinocytes (EC50 3.0–4.1 µm) all with no cytotoxicity. TCS increases oxygen consumption rate in RBL‐2H3 cells. Known mitochondrial uncouplers (e.g., carbonyl cyanide 3‐chlorophenylhydrazone) previously were found to inhibit mast cell function. TCS‐methyl, which has a methyl group in place of the TCS ionizable proton, affects neither degranulation nor ATP production at non‐cytotoxic doses. Thus, the effects of TCS on mast cell function are due to its proton ionophore structure. In addition, 5 µm TCS inhibits thapsigargin‐stimulated degranulation of RBL‐2H3 cells: further evidence that TCS disrupts mast cell signaling. Our data indicate that TCS is a mitochondrial uncoupler, and TCS may affect numerous cell types and functions via this mechanism. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Intersex in fishes and amphibians: population implications, prevalence,
           mechanisms and molecular biomarkers
    • Abstract: Intersex is defined as the abnormal presence of both testicular and ovarian cells in gonads of gonochoristic animals. Its occurrence is widespread and reports on its presence in the gonads of vertebrates continues to increase. In this review, we use standardized terminology to summarize the current knowledge of intersex in gonochoristic fishes and amphibians. We describe the different indices that have been used to assess the severity of intersex and synthesize reports discussing the prevalence of intersex in relation to different types of pollutants. In addition, we evaluate the geographic distribution and chronology of the reported cases of intersex in fishes and amphibians, their pathological descriptions and severity and discuss species sensitivities. We also summarize molecular biomarkers that have been tested for early detection of intersex in wild populations and highlight additional biomarkers that target molecular pathways involved in gonadal development that require further investigation for use in the diagnosis of intersex. Finally, we discuss the needs for future research in this field. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • BDE‐209 inhibits pluripotent genes expression and induces apoptosis
           in human embryonic stem cells
    • Abstract: Decabromodiphenyl ether (BDE‐209) has been detected in human serum, semen, placenta, cord blood and milk worldwide. However, little is known regarding the potential effects on the early human embryonic development of BDE‐209. In this study, human embryonic stem cell lines FY‐hES‐10 and FY‐hES‐26 were used to evaluate the potential effects and explore the toxification mechanisms using low‐level BDE‐209 exposure. Our data showed that BDE‐209 exposure (1, 10 and 100 nM) reduced the expression of pluripotent genes such as OCT4, SOX2 and NANOG and induced human embryonic stem cells (hESCs) apoptosis. The downregulation of BIRC5/BCL2 and upregulation of BAX were related to apoptosis of hESCs induced by BDE‐209 exposure. A mechanism study showed that OCT4 down‐regulation accompanied by OCT4 promoter hypermethylation and increasing miR‐145/miR‐335 levels, OCT4 inhibitors. Moreover, BDE‐209 could increase the generation of intracellular reactive oxygen species (ROS) and decrease SOD2 expression. The ROS increase and OCT4 downregulation after BDE‐209 exposure could be reversed partly by antioxidant N‐acetylcysteine supplement. These findings showed that BDE‐209 exposure could decrease pluripotent genes expression via epigenetic regulation and induce apoptosis through ROS generation in human embryonic stem cells in vitro. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Proposed human stratum corneum water domain in chemical absorption
    • Abstract: Compounds with varying physical and chemical properties may have different affinities to the stratum corneum (SC) and/or its intercellular lipids, keratin protein, and possible water domains. To better understand the mechanism of percutaneous absorption, we utilized 21 carbon‐14 labeled chemicals, with wide hydrophilicity (log P = −0.05 to 6.17), and quantified their absorption/adsorption properties for a short incubation time (15 min) with regards to intact SC membrane, delipidized SC membrane and SC lipid. A facile method was developed for SC/lipid absorption, providing a more equivalent procedure and comparable data. SC lipid absorption of chemical solutes positively correlated with the octanol/water partition coefficient (log P). Differences between the percent dose of chemical absorption to intact SC and the total percent dose contributed by the protein and lipid domains suggest the possibility and significance of a water domain. Absorption rate experiments showed a longer lag time for intact SC than for delipidized SC or SC lipid, suggesting that the water domain may delay chemical binding to protein and lipid domains, and may be a factor in the resistance of many chemicals to current decontamination methods. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Automated swimming activity monitor for examining temporal patterns of
           toxicant effects on individual Daphnia magna
    • Abstract: Aquatic pollutants are often biologically active at low concentrations and impact on biota in combination with other abiotic stressors. Traditional toxicity tests may not detect these effects, and there is a need for sensitive high‐throughput methods for detecting sublethal effects. We have evaluated an automated infra‐red (IR) light‐based monitor for recording the swimming activity of Daphnia magna to establish temporal patterns of toxicant effects on an individual level. Activity was recorded for 48 h and the sensitivity of the monitor was evaluated by exposing D. magna to the reference chemicals K2Cr2O7 at 15, 20 and 25 °C and 2,4‐dichlorophenol at 20 °C. Significant effects (P < 0.001) of toxicant concentrations, exposure time and incubation temperatures were observed. At 15 °C, the swimming activity remained unchanged for 48 h at sublethal concentrations of K2Cr2O7 whereas activity at 20 and 25 °C was more biphasic with decreases in activity occurring after 12–18 h. A similar biphasic pattern was observed after 2,4‐dichlorophenol exposure at 20 °C. EC50 values for 2,4‐dichlorophenol and K2Cr2O7 determined from automated recording of swimming activity showed increasing toxicity with time corresponding to decreases in EC50 of 0.03–0.07 mg l–1 h–1. EC50 values determined after 48 h were comparable or lower than EC50 values based on visual inspection according to ISO 6341. The results demonstrated that the swimming activity monitor is capable of detecting sublethal behavioural effects that are toxicant and temperature dependent. The method allows EC values to be established at different time points and can serve as a high‐throughput screening tool in toxicity testing. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Cytotoxicity and apoptosis induced by silver nanoparticles in human liver
           HepG2 cells in different dispersion media
    • Abstract: Silver nanoparticles (Ag NPs) have been widely used in medical and healthcare products owing to their unique antibacterial activities. However, their safety for humans and the environment has not yet been established. This study evaluated the cellular proliferation and apoptosis of Ag NPs suspended in different solvents using human liver HepG2 cells. The ionization of Ag NPs in different dispersion media [deionized water, phosphate‐buffered saline (PBS), saline and cell culture] was measured using an Ag ion selective electrode. The MTT assay was used to examine the cell proliferation activities. The effects of Ag NPs on cell cycle, induction of apoptosis, production of reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were analyzed using flow cytometry. The degree of Ag NPs ionization differed with dispersion media, with the concentrations of silver ions in deionized water being the highest in all suspensions. Ag NPs could inhibit the viability of HepG2 cells in a time‐ and concentration‐dependent manner. Ag NPs (40, 80 and 160 µg ml−1) exposure could cause cell‐cycle arrest in the G2/M phase, significantly increasing the apoptosis rate and ROS generation, and decreasing the MMP in HepG2 cells more sensitive to deionized water than in cell culture. These results suggested that the cellular toxicological mechanism of Ag NPs might be related to the oxidative stress of cells by the generation of ROS, leading to mitochondria injury and induction of apoptosis. It also implies that it is important to assess the physicochemical properties of NPs in the media where the biological toxicity tests are performed. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Cytochrome P450 induction response in tethered spheroids as a
           three‐dimensional human hepatocyte in vitro model
    • Abstract: Cytochrome P450 (CYP) induction is a key risk factor of clinical drug–drug interactions that has to be mitigated in the early phases of drug discovery. Three‐dimensional (3D) cultures of hepatocytes in vitro have recently emerged as a potentially better platform to recapitulate the in vivo liver structure and to maintain long‐term hepatic functions as compared with conventional two‐dimensional (2D) monolayer cultures. However, the majority of published studies on 3D hepatocyte models use rat hepatocytes and the response to CYP inducers between rodents and humans is distinct. In the present study, we constructed tethered spheroids on RGD/galactose‐conjugated membranes as an in vitro 3D model using cryopreserved human hepatocytes. CYP3A4 mRNA expression in the tethered spheroids was induced to a significantly greater extent than those in the collagen sandwich cultures, indicating the transcriptional regulation was more sensitive to the CYP inducers in the 3D model. Induction of CYP1A2, CYP2B6 and CYP3A4 activities in the tethered spheroids were comparable to, if not higher than that observed in the collagen sandwich cultures. The membrane‐based model is readily integrated into multi‐well plates for higher‐throughput drug testing applications, which might be an alternative model to screen the CYP induction potential in vitro with more physiological relevance. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • An improved model of predicting hepatocarcinogenic potential in rats by
           using gene expression data
    • Abstract: Carcinogenicity studies using animals are expensive and time consuming. Therefore, the development of a highly accurate carcinogenicity prediction system to interpret short‐term test results would be beneficial. The Ames test is popular for mutagens; however, it cannot detect non‐genotoxic carcinogens. Previously, we reported a prediction system using gene expression data obtained from a short‐term (28‐day) study that screened candidate compounds for testing in long‐term carcinogenicity studies. In this study, our system was improved by adding more gene expression data. To establish our new system, we used the data of 93 test compounds (41 hepatocarcinogens and 52 non‐hepatocarcinogens). Analysis of liver gene expression data by dividing compounds into ‘for training’ and ‘for test’ categories (20 cases assigned randomly) using Support Vector Machine (SVM) identified a set of marker probe sets that could be used to predict hepatocarcinogenicity. The assigned 42 probe sets have included the cancer‐ or c‐Myc‐related genes such as Hsp90, Pink1, Hspc111, Fbx29, Hepsin, Syndecan2 and Synbindin. Compared with the older version, the improved system had a higher concordance rate with the training data and a good performance with the external test data. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • An assay to determine the sensitive window of embryos to chemical exposure
           using Xenopus tropicalis
    • Abstract: The frog embryo teratogenesis assay‐Xenopus (FETAX) is an established method to evaluate the developmental toxicity of chemicals. In FETAX, a 48 h continuous exposure is usually conducted when the X. tropicalis embryo is used as the test model. In the present study, we exposed X. tropicalis embryos to nine known teratogens for four separate 12‐h periods. The embryos showed great variations in response to nine tested compounds during different exposure periods. Based on the value of the score of malformations, the most sensitive 12 h exposure periods of embryos were significantly distinguished for all the compounds with the exception of NiCl2. The embryos were the most sensitive to retinols (e.g. all‐trans‐retinoic acid and 9‐cis‐retinoic acid) during 0–12 h and to metal compounds (e.g. triphenlytin and CdCl2) during a 24 to 36 h exposure period. In the further 3 h exposure experiment, the most sensitive period could only be determined for one of three tested compounds. Based on the present results, we proposed an assay to determine a 12 h sensitive window of embryos to chemical exposure using Xenopus tropicalis. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Angiogenesis is repressed by ethanol exposure during chick embryonic
           development
    • Abstract: It is now known that excess alcohol consumption during pregnancy can cause fetal alcohol syndrome to develop. However, it is not known whether excess ethanol exposure could directly affect angiogenesis in the embryo or angiogenesis being indirectly affected because of ethanol‐induced fetal alcohol syndrome. Using the chick yolk sac membrane (YSM) model, we demonstrated that ethanol exposure dramatically inhibited angiogenesis in the YSM of 9‐day‐old chick embryos, in a dose‐dependent manner. Likewise, the anti‐angiogenesis effect of ethanol could be seen in the developing vessel plexus (at the same extra‐embryonic regions) during earlier stages of embryo development. The anti‐angiogenic effect of ethanol was found associated with excess reactive oxygen species (ROS) production; as glutathione peroxidase activity increased while superoxide dismutase 1 and 2 activities decreased in the YSMs. We further validated this observation by exposing chick embryos to 2,2′‐azobis‐amidinopropane dihydrochloride (a ROS inducer) and obtained a similar anti‐angiogenesis effect as ethanol treatment. Semiquantitative reverse transcription–polymerase chain reaction analysis of the experimental YSMs revealed that expression of angiogenesis‐related genes, vascular endothelial growth factor and its receptor, fibroblast growth factor 2 and hypoxia‐inducible factor, were all repressed following ethanol and 2,2′‐azobis‐amidinopropane dihydrochloride treatment. In summary, our results suggest that excess ethanol exposure inhibits embryonic angiogenesis through promoting superfluous ROS production during embryo development. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Investigating the effect of excess caffeine exposure on placental
           angiogenesis using chicken ’functional‘ placental blood vessel
           network
    • Abstract: It is now known that over‐consumption of caffeine by pregnant mothers could have detrimental effects on normal fetal development. However, it remains obscure how caffeine's harmful effect impacts directly or indirectly on the developing embryo/fetus through damaging placenta development. In this study, we demonstrated the morphological similarities between the yolk sac and chorioallantoic membranes (CAM) of chick embryos and the villi of the mammalian placenta. Using the chick yolk sac and the CAM as a model, we found that 5–15 µmol per egg of caffeine exposure inhibited angiogenesis. Under the same condition, cell proliferation in extraembryonic mesoderm was reduced while apoptosis was enhanced. Semi‐quantitative RT‐PCR analysis revealed that caffeine treatment down‐regulated VEGF, VEGFR2, PIGF, IGF2 and NRP1 expression, but up‐regulated Ang1 and Ang2 expression. We performed in situ hybridization to show VE‐cadherin expression and as to demonstrate the blood vessels in the CAM and yolk sac membranes. This distribution of the VE‐cadherin+ blood vessels was determined to be reduced after caffeine treatment. Furthermore, MDA activity was induced after caffeine exposure, but GSH‐PX activity was inhibited after caffeine exposure; SOD activity was unchanged as compared with the control. In summary, our results suggest that caffeine exposure could negatively impact on angiogenesis in the chick yolk sac and CAM by targeting angiogenesis‐related genes. Some of these genes are also involved in regulating excess ROS generation. The results implied that the negative impact of caffeine on fetal development was partly attributed to impaired placental angiogenesis. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Effects of urban particulate matter with high glucose on human monocytes
           U937
    • Abstract: Epidemiological studies and animal experiments have shown that individuals with preexisting diseases, such as diabetes mellitus (DM), are more susceptible to particulate matter (PM)‐related cardiovascular diseases. However, the underlying mechanisms are still unclear. We hypothesized that PM and high glucose combined would cause enhanced effects on activation of monocytes and p38 mitogen‐activated protein kinase (MAPK) by inducing oxidative stress, which would further activate matrix metalloproteinases (MMPs). Human monocytes U937 were used to test the effects of urban particulate matter (U‐PM) and high glucose. The results showed that exposure of monocytes to non‐toxic doses of U‐PM alone caused generation of reactive oxygen species (ROS), increased phosphorylation of p38, and activation of monocytes which was reflected by up‐regulation of MMP‐2, MMP‐9 and proinflammatory cytokines IL‐1β and IL‐8 expression and increased activity of pro‐MMP‐2 and pro‐MMP‐9. These effects were enhanced significantly when cells were exposed to U‐PM in a high‐glucose environment. Our results also showed that pre‐treatment of cells with ROS scavengers or inhibitors abolished U‐PM and high glucose‐induced increased phosphorylation of p38. Up‐regulation of pro‐MMP‐2 and pro‐MMP‐9 activity by U‐PM in the setting of high glucose level was dramatically attenuated by treatment of cells with the p38‐specific inhibitor, SB203580. These results suggest that activation of MMPs by U‐PM with high glucose is partly through p38 phosphorylation that is induced by oxidative stress. Our findings may have important implications in understanding the potential health effects of PM on susceptible populations such as those with DM. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Kupffer cell‐mediated exacerbation of methimazole‐induced
           acute liver injury in rats
    • Abstract: Methimazole (MTZ), an anti‐thyroid drug, is known to cause liver injury in humans. It has been demonstrated that MTZ‐induced liver injury in Balb/c mice is accompanied by T helper (Th) 2 cytokine‐mediated immune responses; however, there is little evidence for immune responses associated with MTZ‐induced liver injury in rats. To investigate species differences in MTZ‐induced liver injury, we administered MTZ with a glutathione biosynthesis inhibitor, L‐buthionine‐S,R‐sulfoximine (BSO), to F344 rats and subsequently observed an increase in plasma alanine aminotransferase (ALT) and high‐mobility group box 1 (HMGB1), which are associated with hepatic lesions. The hepatic mRNA expression of innate immune‐related genes significantly increased in BSO‐ and MTZ‐treated rats, but the change in Th2‐related genes was not much greater than the change observed in the previous mouse study. Moreover, an increase in Kupffer cells and an induction of the phosphorylation of extracellular signal‐regulated kinase (ERK)/c‐Jun N‐terminal kinase (JNK) proteins were accompanied by an increase in Toll‐like receptor 4 (TLR4) expression, indicating that Kupffer cell activation occurs through HMGB1‐TLR4 signaling. To elucidate the mechanism of liver injury in rats, gadolinium chloride, which inactivates the function of Kupffer cells, was administered before BSO and MTZ administration. The gadolinium chloride treatment significantly suppressed the increased ALT, which was accompanied by decreased hepatic mRNA expression related to innate immune responses and ERK/JNK phosphorylation. In conclusion, Kupffer cell‐mediated immune responses are crucial factors for the exacerbation of MTZ‐induced liver injury in rats, indicating apparent species differences in the immune‐mediated exacerbation of liver injury between mice and rats. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • The comparative toxicity of a reduced, crude comfrey (Symphytum
           officinale) alkaloid extract and the pure, comfrey‐derived
           pyrrolizidine alkaloids, lycopsamine and intermedine in chicks (Gallus
           gallus domesticus)
    • Abstract: Comfrey (Symphytum officinale), a commonly used herb, contains dehydropyrrolizidine alkaloids that, as a group of bioactive metabolites, are potentially hepatotoxic, pneumotoxic, genotoxic and carcinogenic. Consequently, regulatory agencies and international health organizations have recommended comfrey be used for external use only. However, in many locations comfrey continues to be ingested as a tisane or as a leafy vegetable. The objective of this work was to compare the toxicity of a crude, reduced comfrey alkaloid extract to purified lycopsamine and intermedine that are major constituents of S. officinale. Male, California White chicks were orally exposed to daily doses of 0.04, 0.13, 0.26, 0.52 and 1.04 mmol lycopsamine, intermedine or reduced comfrey extract per kg bodyweight (BW) for 10 days. After another 7 days chicks were euthanized. Based on clinical signs of poisoning, serum biochemistry, and histopathological analysis the reduced comfrey extract was more toxic than lycopsamine and intermedine. This work suggests a greater than additive effect of the individual alkaloids and/or a more potent toxicity of the acetylated derivatives in the reduced comfrey extract. It also suggests that safety recommendations based on purified compounds may underestimate the potential toxicity of comfrey. Published 2015. This article has been contributed to by US Government employees and their work is in the public domain in the USA.
       
  • Effects of sulpiride and ethylene glycol monomethyl ether on endometrial
           carcinogenicity in Donryu rats
    • Abstract: Sulpiride and ethylene glycol monomethyl ether (EGME) are known ovarian toxicants that stimulate prolactin (PRL) secretion, resulting in hypertrophy of the corpora lutea and increased progesterone (P4) production. The purpose of the present study was to investigate how the PRL stimulatory agents affected uterine carcinogenesis and to clarify the effects of PRL on endometrial adenocarcinoma progression in rats. Ten‐week‐old female Donryu rats were treated once with N‐ethyl‐N′‐nitro‐N‐nitrosoguanidine (20 mg kg−1), followed by treatment with sulpiride (200 ppm) or EGME (1250 ppm) from 11 weeks of age to 12 months of age. Sulpiride treatment inhibited the incidence of uterine adenocarcinoma and precancerous lesions of atypical endometrial hyperplasia, whereas EGME had no effect on uterine carcinogenesis. Sulpiride markedly prevented the onset of persistent estrus throughout the study period, and EGME delayed and inhibited the onset of persistent estrus. Moreover, sulpiride‐treated animals showed high PRL and P4 serum levels without changes in the levels of estradiol‐17β, low uterine weights and histological luteal cell hypertrophy. EGME did not affect serum PRL and P4 levels. These results suggest that the prolonged low estradiol‐17β to P4 ratio accompanied by persistent estrous cycle abnormalities secondary to the luteal stimulatory effects of PRL may explain the inhibitory effects of sulpiride on uterine carcinogenesis in rats. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • The potential health challenges of TiO2 nanomaterials
    • Abstract: Titanium dioxide (TiO2) nanomaterials (NMs) have found widespread applications owing to their attractive physical and chemical properties. As a result, the potential adverse impacts of nano‐TiO2 exposure on humans have become a matter of concern. This review presents the state‐of‐the‐art advances on the investigations of the adverse effects of NMs, including the potential exposure routes of nano‐TiO2 (e.g. respiratory system, skin absorption and digestive system), the physico‐chemical characterizations of nano‐TiO2 (e.g. crystal structure, shape,size, zeta potential, treatment media, aggregation and agglomeration tendency, surface characteristics and coatings), risk evaluation of nanotoxicity (e.g. cytotoxicity, ecotoxicity, phototoxicity, and phytotoxicity) and potential mechanisms of adverse effects (e.g. generation of reactive oxygen species, oxidative stress and organelle dysfunction). The review aims to facilitate scientific assessments of health risks to nano‐TiO2, which would guide the safe applications of NMs in our daily life. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Defensive and adverse energy‐related molecular responses precede
           tris (1, 3‐dichloro‐2‐propyl) phosphate cytotoxicity
    • Abstract: To understand the potentially adverse effects of human exposure to tris (1, 3‐dichloro‐2‐propyl) phosphate (TDCIPP) and explore the underlying molecular mechanisms, combined transcriptomic and metabolomic approaches were employed to investigate the molecular responses of two human cell lines exposed to different concentrations of TDCIPP. Comparative analyses of transcriptional and metabolic profiles of HepG2/C3A and A549 cells were performed after exposure to 1, 10 and 100 μM TDCIPP for 24 and 72 h. Stress responses (e.g. xenobiotic metabolism and ABC transporter pathways) were observed at the transcriptional level after 24‐h exposure to a sub‐cytotoxic concentration (10 μM). Transcription of an energy metabolism‐related pathway (oxidative phosphorylation) was down‐regulated more severely at 100 μM TDCIPP exposure, accompanied by the suppression of pathways relevant to cell proliferation (e.g. cell cycle and DNA replication), while no significant cytotoxic effects were observed. Functional metabolic changes were observed after 72 h in HepG2/C3A cells exposed to 100 μM TDCIPP that corresponded to changes detected at the transcriptional level after 24 h. Taken together, defensive responses to chemical exposure and energy‐related changes both precede the cytotoxic effects of TDCIPP in HepG2/C3A cells. Copyright © 2015 John Wiley & Sons, Ltd.
       
  • Protein profiles of cardiomyocyte differentiation in murine embryonic stem
           cells exposed to perfluorooctane sulfonate
    • Abstract: Perfluorooctane sulfonate (PFOS) is a persistent organic contaminant that may affect diverse systems in animals and humans, including the cardiovascular system. However, little is known about the mechanism by which it affects the biological systems. Herein, we used embryonic stem cell test procedure as a tool to assess the developmental cardiotoxicity of PFOS. The differentially expressed proteins were identified by quantitative proteomics that combines the stable isotope labeling of amino acids with high‐performance liquid chromatography‐electrospray ionization tandem mass spectrometry. Results of the embryonic stem cell test procedure suggested that PFOS was a weak embryotoxic chemical. Nevertheless, a few marker proteins related to cardiovascular development (Brachyury, GATA4, MEF2C, α‐actinin) were significantly reduced by exposure to PFOS. In total, 176 differential proteins were identified by proteomics analysis, of which 67 were upregulated and 109 were downregulated. Gene ontology annotation classified these proteins into 13 groups by molecular functions, 12 groups by cellular locations and 10 groups by biological processes. Most proteins were mainly relevant to either catalytic activity (25.6%), nucleus localization (28.9%) or to cellular component organization (19.8%). Pathway analysis revealed that 32 signaling pathways were affected, particularly these involved in metabolism. Changes in five proteins, including L‐threonine dehydrogenase, X‐ray repair cross‐complementing 5, superoxide dismutase 2, and DNA methyltransferase 3b and 3a were confirmed by Western blotting, suggesting the reliability of the technique. These results revealed potential new targets of PFOS on the developmental cardiovascular system. Copyright © 2015 John Wiley & Sons, Ltd.
       
 
 
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