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  Subjects -> ENVIRONMENTAL STUDIES (Total: 799 journals)
    - ENVIRONMENTAL STUDIES (729 journals)
    - POLLUTION (22 journals)
    - TOXICOLOGY AND ENVIRONMENTAL SAFETY (39 journals)
    - WASTE MANAGEMENT (9 journals)

ENVIRONMENTAL STUDIES (729 journals)            First | 1 2 3 4 5 6 7 8     

Indiana Journal of Global Legal Studies     Full-text available via subscription   (Followers: 2)
Indoor Air     Hybrid Journal   (Followers: 1)
Information Systems Management     Hybrid Journal   (Followers: 22)
Information Technology and Management     Hybrid Journal   (Followers: 9)
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   (Followers: 1)
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: 2)
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: 2)
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: 1)
International Journal of Corrosion     Open Access   (Followers: 10)
International Journal of Critical Infrastructures     Hybrid Journal   (Followers: 3)
International Journal of Disaster Risk Reduction     Hybrid Journal   (Followers: 6)
International Journal of Disaster Risk Science     Open Access   (Followers: 9)
International Journal of Ecological Economics and Statistics     Full-text available via subscription   (Followers: 1)
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: 6)
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 Engineering     Open Access  
International Journal of Environmental Health Research     Hybrid Journal   (Followers: 2)
International Journal of Environmental Policy and Decision Making     Hybrid Journal   (Followers: 10)
International Journal of Environmental Protection     Open Access   (Followers: 12)
International Journal of Environmental Research and Public Health     Open Access   (Followers: 16)
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: 3)
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: 6)
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: 1)
International Journal of Regulation and Governance     Hybrid Journal   (Followers: 2)
International Journal of Reliability and Safety     Hybrid Journal   (Followers: 7)
International Journal of Renewable Energy Development     Open Access   (Followers: 6)
International Journal of Social Sciences and Management     Open Access  
International Journal of Soil, Sediment and Water     Open Access   (Followers: 8)
International Journal of Stress Management     Full-text available via subscription   (Followers: 9)
International Journal of Sustainable Construction Engineering and Technology     Open Access   (Followers: 8)
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: 7)
International Journal of Water Resources and Environmental Engineering     Open Access   (Followers: 1)
International Review of Environmental and Resource Economics     Full-text available via subscription   (Followers: 1)
International Studies in the Philosophy of Science     Hybrid Journal   (Followers: 10)
Interventions : International Journal of Postcolonial Studies     Hybrid Journal   (Followers: 10)
IOP Conference Series: Earth and Environmental Science     Open Access   (Followers: 7)
Iranian Studies     Hybrid Journal   (Followers: 10)
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: 8)
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: 1)
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: 259)
Journal of Applied Meteorology and Climatology     Full-text available via subscription   (Followers: 8)
Journal of Applied Psychoanalytic Studies     Hybrid Journal   (Followers: 1)
Journal of Applied Sciences and Environmental Management     Open Access   (Followers: 1)
Journal of Applied Sciences in Environmental Sanitation     Open Access   (Followers: 6)
Journal of Applied Toxicology     Hybrid Journal   (Followers: 10)

  First | 1 2 3 4 5 6 7 8     

Journal Cover   Journal of Applied Toxicology
  [SJR: 0.799]   [H-I: 53]   [12 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  [1608 journals]
  • Microminipigs as a new experimental animal model for toxicological
           studies: comparative pharmacokinetics of perfluoroalkyl acids
    • Authors: Keerthi S. Guruge; Michiko Noguchi, Koji Yoshioka, Eriko Yamazaki, Sachi Taniyasu, Miyako Yoshioka, Noriko Yamanaka, Mitsutaka Ikezawa, Nobuhiko Tanimura, Masumi Sato, Nobuyoshi Yamashita, Hiroaki Kawaguchi
      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.
      PubDate: 2015-04-15T08:17:20.50335-05:0
      DOI: 10.1002/jat.3145
       
  • Acrylamide induces locomotor defects and degeneration of dopamine neurons
           in Caenorhabditis elegans
    • Authors: Jia Li; Dan Li, Yongsheng Yang, Tiantian Xu, Ping Li, Defu He
      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.
      PubDate: 2015-04-15T07:51:39.378714-05:
      DOI: 10.1002/jat.3144
       
  • PM2.5‐induced oxidative stress increases adhesion molecules
           expression in human endothelial cells through the
           ERK/AKT/NF‐κB‐dependent pathway
    • Authors: Wei Rui; Longfei Guan, Fang Zhang, Wei Zhang, Wenjun Ding
      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.
      PubDate: 2015-04-15T07:37:09.723701-05:
      DOI: 10.1002/jat.3143
       
  • Aluminium oxide nanoparticles induced morphological changes, cytotoxicity
           and oxidative stress in Chinook salmon (CHSE‐214) cells
    • Authors: Koigoora Srikanth; Amit Mahajan, Eduarda Pereira, Armando Costa Duarte, Janapala Venkateswara Rao
      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.
      PubDate: 2015-04-15T07:06:31.862304-05:
      DOI: 10.1002/jat.3142
       
  • Particulate matter phagocytosis induces tissue factor in differentiating
           macrophages
    • Authors: M. Milano; P. Dongiovanni, A. Artoni, S. Gatti, L. Rosso, F. Colombo, V. Bollati, M. Maggioni, P. M. Mannucci, P. A. Bertazzi, S. Fargion, L. Valenti
      Abstract: Airborne exposure to particulate matter with diameter
      PubDate: 2015-04-08T22:41:25.814999-05:
      DOI: 10.1002/jat.3156
       
  • Impaired aquaporins expression in the gastrointestinal tract of rat after
           mercury exposure
    • Authors: Cinzia Bottino; Marta Vázquez, Vicenta Devesa, Umberto Laforenza
      Abstract: The main route of exposure to mercury in humans is through the diet. Consequently, the gastrointestinal mucosa is exposed to the mercurial forms, where they cause intestinal fluid accumulation, mucosal injuries and diarrhea. The relationship between inorganic mercury (HgCl2) and methylmercury (CH3HgCl) exposure and water movement in the gastrointestinal tract is still unexplored. The leading role of aquaporins (AQPs) in the rapid bidirectional movement of fluid in the gastrointestinal tract of mammals is well established. The present study evaluates the effect of HgCl2 and CH3HgCl exposure on AQP expression in different portions of the gastrointestinal tract of rats treated by gavage (5 mg kg–1 of mercury species, single dose, 4 days). The results show that mercury species reduce mRNA and protein levels of AQPs in different parts of the gastrointestinal tract. In the stomach, treated rats show a significant reduction of expression of AQP3 (80–90% for mRNA and 50% for protein) and AQP4 (95–99% for mRNA and 20–40% for protein). In the small and large intestine, treated rats experience a significant reduction of AQP3 and AQP7 expression. Protein contents of both AQPs are reduced in similar proportions in jejunum (AQP3: 40–50%; AQP7: 45–50%) and colon (AQP3: 35–40%; AQP7: 45–60%), regardless of the treatment. Our results indicate that some AQPs are downregulated in the rat gastrointestinal tract by mercury exposure, suggesting a possible role of AQPs in the development of mercury gastrointestinal symptoms. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-04-08T20:55:50.964966-05:
      DOI: 10.1002/jat.3151
       
  • Co‐treatment with the non‐steroidal anti‐androgen drug,
           flutamide and the natural estrogen, 17β‐estradiol does not lead
           to additive reproductive impairment in juvenile Murray rainbowfish
           (Melanotaenia fluviatilis)
    • Authors: Harpreet Bhatia; Anupama Kumar, Jun Du, John C. Chapman, Mike J. McLaughlin
      Abstract: The aim of this study was to investigate if the anti‐androgen, flutamide, and the estrogen, 17β‐estradiol work together to feminize juvenile Murray rainbowfish (Melanotaenia fluviatilis). Fish (60 days post‐hatch) were exposed to 25 ng/L 17β‐estradiol (E2), 25 µg/L flutamide (Flu low), 250 µg/L flutamide (Flu high), E2 + Flu low and E2 + Flu high. After 35 days of exposure, concentrations of sex steroid hormones, 17β‐estradiol and 11‐keto testosterone (11‐KT), were determined in the head; and vitellogenin (VTG) concentration was measured in the tail. The abdomens were used for histological investigation of the gonads. Treatment with E2 + Flu high resulted in reduction in body weights and lengths in males and condition factor in females. Intersex was noted in Flu high and E2 + Flu high treatments. Exposures to E2 and/or Flu (low and high) resulted in precocious oocyte development but inhibited sperm development. The 17β‐estradiol levels decreased significantly in the heads of both sexes after exposures to E2 and/or Flu (high and low). Flu high and E2 alone increased the 11‐KT levels in both sexes. However, E2 + Flu low decreased 11‐KT levels in males and increased them in females. Flutamide (low and high) induced VTG protein in the tails of both sexes. In males, VTG was not induced in the tail after exposure to E2. No significant effect of flutamide on E2‐induced VTG concentration was noted. We conclude that co‐treatment with flutamide and 17β‐estradiol does not lead to additive reproductive impairment in juvenile Murray rainbowfish. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-04-08T07:40:51.66153-05:0
      DOI: 10.1002/jat.3135
       
  • Titanium dioxide nanoparticles increase plasma glucose via reactive oxygen
           species‐induced insulin resistance in mice
    • Authors: Hailong Hu; Qian Guo, Changlin Wang, Xiao Ma, Hongjuan He, Yuri Oh, Yujie Feng, Qiong Wu, Ning Gu
      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.
      PubDate: 2015-03-31T05:59:02.869333-05:
      DOI: 10.1002/jat.3150
       
  • Augmenting effects of gestational arsenite exposure of C3H mice on the
           hepatic tumors of the F2 male offspring via the F1 male offspring
    • Authors: Keiko Nohara; Kazuyuki Okamura, Takehiro Suzuki, Hikari Murai, Takaaki Ito, Keiko Shinjo, Shota Takumi, Takehiro Michikawa, Yutaka Kondo, Kenichiro Hata
      Abstract: Gestational exposure can affect the F2 generation through exposure of F1 germline cells. Previous studies reported that arsenite exposure of only F0 females during their pregnancy increases hepatic tumors in the F1 males in C3H mice, whose males are predisposed spontaneously to develop hepatic tumors later in life. The present study addressed the effects of gestational arsenite exposure on tumorigenesis of the F2 males in C3H mice. Expression analysis of several genes in the normal livers at 53 and 80 weeks of age clearly showed significant changes in the F2 males obtained by crossing gestational arsenite‐exposed F1 (arsenite‐F1) males and females compared to the control F2 males. Some of the changes were shown to occur in a late‐onset manner. Then the tumor incidence was assessed at 75–82 weeks of age in the F2 males obtained by reciprocal crossing between the control and arsenite‐F1 males and females. The results demonstrated that the F2 males born to arsenite‐F1 males developed tumors at a significantly higher rate than the F2 males born to the control F1 males, irrespective of exposure of F1 females. Gene expressions of hepatocellular carcinoma markers β‐catenin (CTNNB1) and interleukin‐1 receptor antagonist in the tumors were significantly upregulated in the F2 males born to arsenite‐F1 males compared to those born to the control F1 males. These results show that arsenite exposure of only F0 pregnant mice causes late‐onset changes and augments tumors in the livers of the F2 males by affecting the F1 male offspring. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-03-30T22:47:14.094101-05:
      DOI: 10.1002/jat.3149
       
  • Gene expression profiling of the hippocampal dentate gyrus in an adult
           toxicity study captures a variety of neurodevelopmental dysfunctions in
           rat models of hypothyroidism
    • Authors: Ayako Shiraki; Fumiyo Saito, Hirotoshi Akane, Yumi Akahori, Nobuya Imatanaka, Megu Itahashi, Toshinori Yoshida, Makoto Shibutani
      Abstract: We previously found that developmental hypothyroidism changed the expression of genes in the rat hippocampal dentate gyrus, a brain region where adult neurogenesis is known to occur. In the present study, we performed brain region‐specific global gene expression profiling in an adult rat hypothyroidism model to see if it reflected the developmental neurotoxicity we saw in the developmental hypothyroidism model. Starting when male rats were 5 weeks old, we administered 6‐propyl‐2‐thiouracil at a doses of 0, 0.1 and 10 mg kg−1 body weight by gavage for 28 days. We selected four brain regions to represent both cerebral and cerebellar tissues: hippocampal dentate gyrus, cerebral cortex, corpus callosum and cerebellar vermis. We observed significant alterations in the expression of genes related to neural development (Eph family genes and Robo3) in the cerebral cortex and hippocampal dentate gyrus and in the expression of genes related to myelination (Plp1 and Mbp) in the hippocampal dentate gyrus. We observed only minor changes in the expression of these genes in the corpus callosum and cerebellar vermis. We used real‐time reverse‐transcription polymerase chain reaction to confirm Chrdl1, Hes5, Mbp, Plp1, Slit1, Robo3 and the Eph family transcript expression changes. The most significant changes in gene expression were found in the dentate gyrus. Considering that the gene expression profile of the adult dentate gyrus closely related to neurogenesis, 28‐day toxicity studies looking at gene expression changes in adult hippocampal dentate gyrus may also detect possible developmental neurotoxic effects. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-03-30T20:50:06.345358-05:
      DOI: 10.1002/jat.3140
       
  • Development of toxicity values and exposure estimates for
           tetrabromobisphenol A: application in a margin of exposure assessment
    • Authors: Daniele Wikoff; Chad Thompson, Camarie Perry, Matthew White, Susan Borghoff, Lauren Fitzgerald, Laurie C. Haws
      Abstract: Tetrabromobisphenol A (TBBPA) is used in a diverse array of products to improve fire safety. The National Toxicology Program (NTP) recently completed a 2‐year bioassay for TBBPA. The objective of the present study was to develop a cancer‐based and a non‐cancer based toxicity value and to compare such to appropriate estimates of human exposure. Data from the NTP 2‐year and 13‐week studies were selected to develop candidate toxicity values. Benchmark dose modeling and subsequent evaluation of candidate values resulted in selection of an oral reference dose (RfD) of 0.6 mg kg−1 day−1 based on uterine hyperplasia in rats and an oral cancer slope factor (OSF) of 0.00315 per mg kg−1 day−1 based on an increased incidence of uterine tumors in rats. Lifetime average daily dose (LADD) estimates ranged from 2.2 E−7 to 3.9 E−6 mg kg−1 day−1 based on age‐adjusted exposures to TBBPA via breast milk consumption, dietary intake, soil/dust ingestion and drinking water ingestion in infants, young children, older children and adults. Average daily dose (ADD) estimates ranged from 3.2 E −7 to 8.4 E−5 mg kg−1 day−1. Resulting margin of exposure (MOE) values were > 800 000 for non‐cancer endpoints and > 32 000 000 for cancer‐based endpoints. These data collectively indicate a low level of health concern associated with exposures to TBBPA based on current data. It is anticipated that the exposure estimates, along with the toxicity values described within, should be informative for understanding human health hazards associated with TBBPA. © 2015. The
      Authors . Journal of Applied Toxicology Published by John Wiley & Sons Ltd.
      PubDate: 2015-03-30T20:10:22.288627-05:
      DOI: 10.1002/jat.3132
       
  • Evaluation of combinations of in vitro sensitization test descriptors for
           the artificial neural network‐based risk assessment model of skin
           sensitization
    • Authors: Morihiko Hirota; Shiho Fukui, Kenji Okamoto, Satoru Kurotani, Noriyasu Imai, Miyuki Fujishiro, Daiki Kyotani, Yoshinao Kato, Toshihiko Kasahara, Masaharu Fujita, Akemi Toyoda, Daisuke Sekiya, Shinichi Watanabe, Hirokazu Seto, Osamu Takenouchi, Takao Ashikaga, Masaaki Miyazawa
      Abstract: The skin sensitization potential of chemicals has been determined with the use of the murine local lymph node assay (LLNA). However, in recent years public concern about animal welfare has led to a requirement for non‐animal risk assessment systems for the prediction of skin sensitization potential, to replace LLNA. Selection of an appropriate in vitro test or in silico model descriptors is critical to obtain good predictive performance. Here, we investigated the utility of artificial neural network (ANN) prediction models using various combinations of descriptors from several in vitro sensitization tests. The dataset, collected from published data and from experiments carried out in collaboration with the Japan Cosmetic Industry Association (JCIA), consisted of values from the human cell line activation test (h‐CLAT), direct peptide reactivity assay (DPRA), SH test and antioxidant response element (ARE) assay for chemicals whose LLNA thresholds have been reported. After confirming the relationship between individual in vitro test descriptors and the LLNA threshold (e.g. EC3 value), we used the subsets of chemicals for which the requisite test values were available to evaluate the predictive performance of ANN models using combinations of h‐CLAT/DPRA (N = 139 chemicals), the DPRA/ARE assay (N = 69), the SH test/ARE assay (N = 73), the h‐CLAT/DPRA/ARE assay (N = 69) and the h‐CLAT/SH test/ARE assay (N = 73). The h‐CLAT/DPRA, h‐CLAT/DPRA/ARE assay and h‐CLAT/SH test/ARE assay combinations showed a better predictive performance than the DPRA/ARE assay and the SH test/ARE assay. Our data indicates that the descriptors evaluated in this study were all useful for predicting human skin sensitization potential, although combinations containing h‐CLAT (reflecting dendritic cell‐activating ability) were most effective for ANN‐based prediction. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-03-30T19:40:57.244347-05:
      DOI: 10.1002/jat.3105
       
  • Test battery with the human cell line activation test, direct peptide
           reactivity assay and DEREK based on a 139 chemical data set for predicting
           skin sensitizing potential and potency of chemicals
    • Authors: Osamu Takenouchi; Shiho Fukui, Kenji Okamoto, Satoru Kurotani, Noriyasu Imai, Miyuki Fujishiro, Daiki Kyotani, Yoshinao Kato, Toshihiko Kasahara, Masaharu Fujita, Akemi Toyoda, Daisuke Sekiya, Shinichi Watanabe, Hirokazu Seto, Morihiko Hirota, Takao Ashikaga, Masaaki Miyazawa
      Abstract: To develop a testing strategy incorporating the human cell line activation test (h‐CLAT), direct peptide reactivity assay (DPRA) and DEREK, we created an expanded data set of 139 chemicals (102 sensitizers and 37 non‐sensitizers) by combining the existing data set of 101 chemicals through the collaborative projects of Japan Cosmetic Industry Association. Of the additional 38 chemicals, 15 chemicals with relatively low water solubility (log Kow > 3.5) were selected to clarify the limitation of testing strategies regarding the lipophilic chemicals. Predictivities of the h‐CLAT, DPRA and DEREK, and the combinations thereof were evaluated by comparison to results of the local lymph node assay. When evaluating 139 chemicals using combinations of three methods based on integrated testing strategy (ITS) concept (ITS‐based test battery) and a sequential testing strategy (STS) weighing the predictive performance of the h‐CLAT and DPRA, overall similar predictivities were found as before on the 101 chemical data set. An analysis of false negative chemicals suggested a major limitation of our strategies was the testing of low water‐soluble chemicals. When excluded the negative results for chemicals with log Kow > 3.5, the sensitivity and accuracy of ITS improved to 97% (91 of 94 chemicals) and 89% (114 of 128). Likewise, the sensitivity and accuracy of STS to 98% (92 of 94) and 85% (111 of 129). Moreover, the ITS and STS also showed good correlation with local lymph node assay on three potency classifications, yielding accuracies of 74% (ITS) and 73% (STS). Thus, the inclusion of log Kow in analysis could give both strategies a higher predictive performance. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-03-29T21:26:10.794897-05:
      DOI: 10.1002/jat.3127
       
  • A novel in chemico method to detect skin sensitizers in highly diluted
           reaction conditions
    • Authors: Yusuke Yamamoto; Haruna Tahara, Ryota Usami, Toshihiko Kasahara, Yoshihiro Jimbo, Takanori Hioki, Masaharu Fujita
      Abstract: The direct peptide reactivity assay (DPRA) is a simple and versatile alternative method for the evaluation of skin sensitization that involves the reaction of test chemicals with two peptides. However, this method requires concentrated solutions of test chemicals, and hydrophobic substances may not dissolve at the concentrations required. Furthermore, hydrophobic test chemicals may precipitate when added to the reaction solution. We previously established a high‐sensitivity method, the amino acid derivative reactivity assay (ADRA). This method uses novel cysteine (NAC) and novel lysine derivatives (NAL), which were synthesized by introducing a naphthalene ring to the amine group of cysteine and lysine residues. In this study, we modified the ADRA method by reducing the concentration of the test chemicals 100‐fold. We investigated the accuracy of skin sensitization predictions made using the modified method, which was designated the ADRA‐dilutional method (ADRA‐DM). The predictive accuracy of the ADRA‐DM for skin sensitization was 90% for 82 test chemicals which were also evaluated via the ADRA, and the predictive accuracy in the ADRA‐DM was higher than that in the ADRA and DPRA. Furthermore, no precipitation of test compounds was observed at the initiation of the ADRA‐DM reaction. These results show that the ADRA‐DM allowed the use of test chemicals at concentrations two orders of magnitude lower than that possible with the ADRA. In addition, ADRA‐DM does not have the restrictions on test compound solubility that were a major problem with the DPRA. Therefore, the ADRA‐DM is a versatile and useful method. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-03-25T00:19:24.155741-05:
      DOI: 10.1002/jat.3139
       
  • Particle uptake efficiency is significantly affected by type of capping
           agent and cell line
    • Authors: Fan Zhang; Phillip Durham, Christie M. Sayes, Boris L. T. Lau, Erica D. Bruce
      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.
      PubDate: 2015-03-24T23:21:44.462642-05:
      DOI: 10.1002/jat.3138
       
  • Comparative effects of sulfhydryl compounds on target organellae, nuclei
           and mitochondria, of hydroxylated fullerene‐induced cytotoxicity in
           isolated rat hepatocytes
    • Authors: Yoshio Nakagawa; Akiko Inomata, Akio Ogata, Dai Nakae
      Abstract: DNA damage and cytotoxicity induced by a hydroxylated fullerene [C60(OH)24], which is a spherical nanomaterial and/or a water‐soluble fullerene derivative, and their protection by sulfhydryl compounds were studied in freshly isolated rat hepatocytes. The exposure of hepatocytes to C60(OH)24 at a concentration of 50 μM caused time (0 to 3 h)‐dependent cell death accompanied by the formation of cell surface blebs, the loss of cellular levels of ATP and reduced glutathione, accumulation of glutathione disulfide, and induction of DNA fragmentation assayed using alkali single‐cell agarose‐gel electrophoresis. C60(OH)24‐induced cytotoxicity was effectively prevented by pretreatment with sulfhydryl compounds. N‐acetyl‐L‐cysteine (NAC), L‐cysteine and L‐methionine, at a concentration of 2.5 mM, ameliorated cell death, accompanied by a decrease in cellular ATP levels, formation of cell surface blebs, induction of reactive oxygen species (ROS) and loss of mitochondrial membrane potential caused by C60(OH)24. In addition, DNA fragmentation caused by C60(OH)24 was also inhibited by NAC, whereas an antioxidant ascorbic acid did not affect C60(OH)24‐induced cell death and DNA damage in rat hepatocytes. Taken collectively, these results indicate that incubation of rat hepatocytes with C60(OH)24 elicits DNA damage, suggesting that nuclei as well as mitochondria are target sites of the hydroxylated fullerene; and induction of DNA damage and oxidative stress is ameliorated by an increase in cellular GSH levels, suggesting that the onset of toxic effects may be partially attributable to a thiol redox‐state imbalance caused by C60(OH)24. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-03-23T04:41:18.036497-05:
      DOI: 10.1002/jat.3137
       
  • Metals in cosmetics: implications for human health
    • Authors: Sylwia Borowska; Malgorzata M. Brzóska
      Abstract: Cosmetics, preparations repeatedly applied directly to the human skin, mucous membranes, hair and nails, should be safe for health, however, recently there has been increasing concern about their safety. Unfortunately, using these products in some cases is related to the occurrence of unfavourable effects resulting from intentional or the accidental presence of chemical substances, including toxic metals. Heavy metals such as lead, mercury, cadmium, arsenic and nickel, as well as aluminium, classified as a light metal, are detected in various types of cosmetics (colour cosmetics, face and body care products, hair cosmetics, herbal cosmetics, etc.). In addition, necessary, but harmful when they occur in excessive amounts, elements such as copper, iron, chromium and cobalt are also present in cosmetic products. Metals occurring in cosmetics may undergo retention and act directly in the skin or be absorbed through the skin into the blood, accumulate in the body and exert toxic effects in various organs. Some cases of topical (mainly allergic contact dermatitis) and systemic effects owing to exposure to metals present in cosmetics have been reported. Literature data show that in commercially available cosmetics toxic metals may be present in amounts creating a danger to human health. Thus, the present review article focused on the problems related to the presence of heavy metals and aluminium in cosmetics, including their sources, concentrations and law regulations as well as danger for the health of these products users. Owing to the growing usage of cosmetics it is necessary to pay special attention to these problems. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-03-23T02:26:14.0959-05:00
      DOI: 10.1002/jat.3129
       
  • Meloxicam inhibits fipronil‐induced apoptosis via modulation of the
           oxidative stress and inflammatory response in SH‐SY5Y cells
    • Authors: Jae Hyeon Park; Youn Sun Park, Je‐Bong Lee, Kyung‐Hun Park, Min‐kyoung Paik, Mihye Jeong, Hyun Chul Koh
      Abstract: Oxidative stress and inflammatory responses have been identified as key elements of neuronal cell apoptosis. In this study, we investigated the mechanisms by which inflammatory responses contribute to apoptosis in human neuroblastoma SH‐SY5Y cells treated with fipronil (FPN). Based on the cytotoxic mechanism of FPN, we examined the neuroprotective effects of meloxicam against FPN‐induced neuronal cell death. Treatment of SH‐SY5Y cells with FPN induced apoptosis via activation of caspase‐9 and ‐3, leading to nuclear condensation. In addition, FPN induced oxidative stress and increased expression of cyclooxygenase‐2 (COX‐2) and tumor necrosis factor‐α (TNF‐α) via inflammatory stimulation. Pretreatment of cells with meloxicam enhanced the viability of FPN‐exposed cells through attenuation of oxidative stress and inflammatory response. FPN activated mitogen activated protein kinase (MAPK) and inhibitors of MAPK abolished FPN‐induced COX‐2 expression. Meloxicam also attenuated FPN‐induced cell death by reducing MAPK‐mediated pro‐inflammatory factors. Furthermore, we observed both nuclear accumulation of p53 and enhanced levels of cytosolic p53 in a concentration‐dependent manner after FPN treatment. Pretreatment of cells with meloxicam blocked the translocation of p53 from the cytosol to the nucleus. Together, these data suggest that meloxicam may exert anti‐apoptotic effects against FPN‐induced cytotoxicity by both attenuating oxidative stress and inhibiting the inflammatory cascade via inactivation of MAPK and p53 signaling. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-03-13T12:18:27.333032-05:
      DOI: 10.1002/jat.3136
       
  • Investigation on cobalt‐oxide nanoparticles cyto‐genotoxicity
           and inflammatory response in two types of respiratory cells
    • Authors: Delia Cavallo; Aureliano Ciervo, Anna Maria Fresegna, Raffaele Maiello, Paola Tassone, Giuliana Buresti, Stefano Casciardi, Sergio Iavicoli, Cinzia Lucia Ursini
      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.
      PubDate: 2015-03-13T12:08:33.285112-05:
      DOI: 10.1002/jat.3133
       
  • Cellular localization of uranium in the renal proximal tubules during
           acute renal uranium toxicity
    • Authors: Shino Homma‐Takeda; Keisuke Kitahara, Kyoko Suzuki, Benjamin J. Blyth, Noriyoshi Suya, Teruaki Konishi, Yasuko Terada, Yoshiya Shimada
      Abstract: Renal toxicity is a hallmark of uranium exposure, with uranium accumulating specifically in the S3 segment of the proximal tubules causing tubular damage. As the distribution, concentration and dynamics of accumulated uranium at the cellular level is not well understood, here, we report on high‐resolution quantitative in situ measurements by high‐energy synchrotron radiation X‐ray fluorescence analysis in renal sections from a rat model of uranium‐induced acute renal toxicity. One day after subcutaneous administration of uranium acetate to male Wistar rats at a dose of 0.5 mg uranium kg–1 body weight, uranium concentration in the S3 segment of the proximal tubules was 64.9 ± 18.2 µg g–1, sevenfold higher than the mean renal uranium concentration (9.7 ± 2.4 µg g–1). Uranium distributed into the epithelium of the S3 segment of the proximal tubules and highly concentrated uranium (50‐fold above mean renal concentration) in micro‐regions was found near the nuclei. These uranium levels were maintained up to 8 days post‐administration, despite more rapid reductions in mean renal concentration. Two weeks after uranium administration, damaged areas were filled with regenerating tubules and morphological signs of tissue recovery, but areas of high uranium concentration (100‐fold above mean renal concentration) were still found in the epithelium of regenerating tubules. These data indicate that site‐specific accumulation of uranium in micro‐regions of the S3 segment of the proximal tubules and retention of uranium in concentrated areas during recovery are characteristics of uranium behavior in the kidney. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-03-13T11:52:31.309239-05:
      DOI: 10.1002/jat.3126
       
  • Time profiles and toxicokinetic parameters of key biomarkers of exposure
           to cypermethrin in orally exposed volunteers compared with previously
           available kinetic data following permethrin exposure
    • Authors: Mylène Ratelle; Jonathan Coté, Michèle Bouchard
      Abstract: Biomonitoring of pyrethroid exposure is largely conducted but human toxicokinetics has not been fully documented. This is essential for a proper interpretation of biomonitoring data. Time profiles and toxicokinetic parameters of key biomarkers of exposure to cypermethrin in orally exposed volunteers have been documented and compared with previously available kinetic data following permethrin dosing. Six volunteers ingested 0.1 mg kg–1 bodyweight of cypermethrin acutely. The same volunteers were exposed to permethrin earlier. Blood samples were taken over 72 h after treatment and complete timed urine voids were collected over 84 h postdosing. Cis‐ and trans‐3‐(2,2‐dichlorovinyl)‐2,2‐dimethylcyclopropane‐1‐carboxylic acids (trans‐ and cis‐DCCA) and 3‐phenoxybenzoic acid (3‐PBA) metabolites, common to both cypermethrin and permethrin, were quantified. Blood and urinary time courses of all three metabolites were similar following cypermethrin and permethrin exposure. Plasma levels of metabolites reached peak values on average ≈ 5–7 h post‐dosing; the elimination phase showed mean apparent half‐lives (t½) for trans‐DCCA, cis‐DCCA and 3‐PBA of 5.1, 6.9 and 9.2 h, respectively, following cypermethrin treatment as compared to 7.1, 6.2 and 6.5 h after permethrin dosing. Corresponding mean values obtained from urinary rate time courses were peak values at ≈ 9 h post‐dosing and apparent elimination t½ of 6.3, 6.4 and 6.4 h for trans‐DCCA, cis‐DCCA and 3‐PBA, respectively, following cypermethrin treatment as compared to 5.4, 4.5 and 5.7 h after permethrin dosing. These data confirm that the kinetics of cypermethrin is similar to that of permethrin in humans and that their common biomarkers of exposure may be used for an overall assessment of exposure. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-03-13T11:33:30.932661-05:
      DOI: 10.1002/jat.3124
       
  • Non‐clinical safety assessment of single and repeated intramuscular
           administration of a human papillomavirus‐16/18 vaccine in rabbits
           and rats
    • Authors: Lawrence Segal; Danielle Morelle, Kari Kaaber, Eric Destexhe, Nathalie Garçon
      Abstract: The human papillomavirus (HPV)‐16/18 vaccine (Cervarix®) is a prophylactic vaccine for the prevention of cervical cancer. The vaccine contains recombinant virus‐like particles assembled from the L1 major capsid proteins of the cervical cancer‐causing viral types HPV‐16 and HPV‐18, and Adjuvant System 04 (AS04), which contains the immunostimulant MPL and aluminium salt. To evaluate potential local and systemic toxic effects of the HPV‐16/18 vaccine or AS04 alone, three repeated‐dose studies were performed in rabbits and rats. One rabbit study also included a single‐dose evaluation. In rabbits (~2.5 kg), the full human dose (HD) of the vaccine was evaluated (0.5 ml per injection site), and in rats (~250 g), 1/5 HD of vaccine was evaluated, corresponding to ≥ 12 times the dosage in humans relative to body weight. In both animal models, the treatment‐related changes included a slight transient increase in the number of circulating neutrophils as well as a local inflammatory reaction at the injection site. These treatment‐related changes were less pronounced after four doses of AS04 alone than after four doses of the HPV‐16/18 vaccine. Additional treatment‐related changes in the rat included lower albumin/globulin ratios and microscopic signs of inflammation in the popliteal lymph nodes. In both animal models, 13 weeks after the fourth dose, recovery was nearly complete, although at the injection site in some animals there were signs of discoloration, muscle‐fibre regeneration and focal points of macrophage infiltration. Therefore, in these non‐clinical models, the single and repeated dose administrations of the HPV‐16/18 vaccine or AS04 alone were safe and well tolerated. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-03-06T09:02:51.11051-05:0
      DOI: 10.1002/jat.3131
       
  • Comparative toxicity of silicon dioxide, silver and iron oxide
           nanoparticles after repeated oral administration to rats
    • Authors: Jun‐Won Yun; Seung‐Hyun Kim, Ji‐Ran You, Woo Ho Kim, Ja‐June Jang, Seung‐Kee Min, Hee Chan Kim, Doo Hyun Chung, Jayoung Jeong, Byeong‐Cheol Kang, Jeong‐Hwan Che
      Abstract: Although silicon dioxide (SiO2), silver (Ag) and iron oxide (Fe2O3) nanoparticles are widely used in diverse applications from food to biomedicine, in vivo toxicities of these nanoparticles exposed via the oral route remain highly controversial. To examine the systemic toxicity of these nanoparticles, well‐dispersed nanoparticles were orally administered to Sprague–Dawley rats daily over a 13‐week period. Based on the results of an acute toxicity and a 14‐day repeated toxicity study, 975.9, 1030.5 and 1000 mg kg–1 were selected as the highest dose of the SiO2, Ag and Fe2O3 nanoparticles, respectively, for the 13‐week repeated oral toxicity study. The SiO2 and Fe2O3 nanoparticles did not induce dose‐related changes in a number of parameters associated with the systemic toxicity up to 975.9 and 1000 mg kg–1, respectively, whereas the Ag nanoparticles resulted in increases in serum alkaline phosphatase and calcium as well as lymphocyte infiltration in liver and kidney, raising the possibility of liver and kidney toxicity induced by the Ag nanoparticles. Compared with the SiO2 and Fe2O3 nanoparticles showing no systemic distribution in all tissues tested, the Ag concentration in sampled blood and organs in the Ag nanoparticle‐treated group significantly increased with a positive and/or dose‐related trend, meaning that the systemic toxicity of the Ag nanoparticles, including liver and kidney toxicity, might be explained by extensive systemic distribution of Ag originating from the Ag nanoparticles. Our current results suggest that further study is required to identify that Ag detected outside the gastrointestinal tract were indeed a nanoparticle form or ionized form. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-03-06T08:26:46.365271-05:
      DOI: 10.1002/jat.3125
       
  • Potential of biofluid components to modify silver nanoparticle toxicity
    • Authors: Anna Murphy; Kate Sheehy, Alan Casey, Gordon Chambers
      Abstract: Establishing realistic exposure scenarios is critical for cytotoxic investigation of silver nanoparticles (AgNP) in the gastrointestinal tract. This study investigated the potential interaction with and effect of biofluid components, namely cholic acid, deoxycholic acid and ursodeoxycholic acid, on AgNP toxicity. Two cell lines corresponding to organs related to the biofluid components were employed. These were HepG‐2 a hepatocellular carcinoma derived from liver tissue and Hep2 an epithelial cell line. Physiochemical and cytotoxic screening was performed and the ability of biofluid components to modify AgNP cytotoxicity was explored. No alteration to the physiochemical characteristics of AgNP by biofluid components was demonstrated. However, biofluid component addition resulted in alteration of AgNP toxicity. Greater reactive oxygen species induction was noted in the presence of cholic acid and deoxycholic acid. Ursodeoxycholic acid demonstrated no modification of toxicity in HepG‐2 cells; however, significant modification was noted in Hep2 cells. It is concluded that biofluid components can modify AgNP toxicity but this is dependent on the biofluid component itself and the location where it acts. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-03-06T08:15:00.892247-05:
      DOI: 10.1002/jat.3123
       
  • T‐helper cell‐mediated factors in drug‐induced liver
           injury
    • Authors: Xinzhi Wang; Luyong Zhang, Zhenzhou Jiang
      Abstract: Drug‐induced liver injury (DILI) leads to a large burden on the healthcare system due to its potential morbidity and mortality. The key for predicting and preventing DILI is to understand the underlying mechanisms. Hepatic inflammation is one of the most common features of DILI. The inflammation can be attributed to the innate immune response. The adaptive immune system is also affected by the innate immune response resulting in liver damage. T‐helper cells are important regulators of acquired immunity. T‐helper cell‐mediated immune responses play pivotal roles in the pathogenesis of a variety of liver disorders. This review summarizes recent advances in the T‐helper cell‐mediated factors in DILI and potential mechanisms, which may lead to a better understanding of DILI. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-03-06T08:01:17.043191-05:
      DOI: 10.1002/jat.3115
       
  • Non‐clinical safety and biodistribution of AS03‐adjuvanted
           inactivated pandemic influenza vaccines
    • Authors: Lawrence Segal; Sandrine Wouters, Danielle Morelle, Gaëlle Gautier, Julien Le Gal, Thomas Martin, Frieke Kuper, Eric Destexhe, Arnaud M. Didierlaurent, Nathalie Garçon
      Abstract: Pandemic‐influenza vaccines containing split‐inactivated‐virus antigen have been formulated with the immunostimulatory Adjuvant System AS03 to enhance the antigen immunogenicity and reduce antigen content per dose. AS03 is an oil‐in‐water emulsion containing α‐tocopherol, squalene and polysorbate 80. To support the clinical development of AS03‐adjuvanted pandemic‐influenza vaccines, the local and systemic toxicity of test articles containing split‐influenza A(H5N1) and/or AS03 were evaluated after 3–4 intramuscular (i.m.) injections in rabbits. Treatment‐related effects were restricted to mild inflammatory responses and were induced primarily by the test articles containing AS03. The injection‐site inflammation was mild at 3 days, and minimal at 4 weeks after the last injection; and was reflected by signs of activation in the draining lymph nodes and by systemic effects in the blood including a transient increase of neutrophils. In addition, a study in mice explored the biodistribution of A(H5N1) vaccines or AS03 through radiolabelling the antigen or constituents of AS03 prior to injection. In this evaluation, 57–73% of AS03's principal constituents had cleared from the injection site 3 days after injection, and their different clearance kinetics were suggestive of AS03's dissociation. All these AS03 constituents entered into the draining lymph nodes within 30 min after injection. In conclusion, the administration of repeated doses of the H5N1/AS03 vaccine was well tolerated in the rabbit, and was primarily associated with transient mild inflammation at the injection site and draining lymph nodes. The biodistribution kinetics of AS03 constituents in the mouse were consistent with AS03 inducing this pattern of inflammation. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-02-27T07:18:21.001473-05:
      DOI: 10.1002/jat.3130
       
  • Toxicity induced by Basic Violet 14, Direct Red 28 and Acid Red 26 in
           zebrafish larvae
    • Authors: Bing Shen; Hong‐Cui Liu, Wen‐Bin Ou, Grant Eilers, Sheng‐Mei Zhou, Fan‐Guo Meng, Chun‐Qi Li, Yong‐Quan Li
      Abstract: Basic Violet 14, Direct Red 28 and Acid Red 26 are classified as carcinogenic dyes in the European textile ecology standard, despite insufficient toxicity data. In this study, the toxicity of these dyes was assessed in a zebrafish model, and the underlying toxic mechanisms were investigated. Basic Violet 14 and Direct Red 28 showed acute toxicity with a LC50 value at 60.63 and 476.84 µg ml–1, respectively, whereas the LC50 of Acid Red 26 was between 2500 and 2800 µg ml–1. Treatment with Basic Violet 14, Direct Red 28 and Acid Red 26 resulted in common developmental abnormalities including delayed yolk sac absorption and swimming bladder deflation. Hepatotoxicity was observed in zebrafish treated with Basic Violet 14, and cardiovascular toxicity was found in zebrafish treated with Acid Red 26 at concentrations higher than 2500 µg ml–1. Basic Violet 14 also caused significant up‐regulation of GCLC gene expression in a dose‐dependent manner whereas Acid Red 26 induced significant up‐regulation of NKX2.5 and down‐regulation of GATA4 at a high concentration in a dose‐dependent manner. These results suggest that Basic Violet 14, Direct Red 28 and Acid Red 26 induce developmental and organ‐specific toxicity, and oxidative stress may play a role in the hepatotoxicity of Basic Violet 14, the suppressed GATA4 expression may have a relation to the cardiovascular toxicity of Acid Red 26. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-02-27T06:35:48.327256-05:
      DOI: 10.1002/jat.3134
       
  • Distribution and biomarkers of carbon‐14‐labeled fullerene C60
           ([14C(U)]C60) in female rats and mice for up to 30 days after intravenous
           exposure
    • Authors: Susan C. J. Sumner; Rodney W. Snyder, Christopher Wingard, Ninell P. Mortensen, Nathan A. Holland, Jonathan H. Shannahan, Suraj Dhungana, Wimal Pathmasiri, Li Han, Anita H. Lewin, Timothy R. Fennell
      Abstract: A comprehensive distribution study was conducted in female rats and mice exposed to a suspension of uniformly carbon‐14‐labeled C60 ([14C(U)]C60). Rodents were administered [14C(U)]C60 (~0.9 mg kg−1 body weight) or 5% polyvinylpyrrolidone‐saline vehicle alone via a single tail vein injection. Tissues were collected at 1 h and 1, 7, 14 and 30 days after administration. A separate group of rodents received five daily injections of suspensions of either [14C(U)]C60 or vehicle with tissue collection 14 days post exposure. Radioactivity was detected in over 20 tissues at all time points. The highest concentration of radioactivity in rodents at each time point was in liver, lungs and spleen. Elimination of [14C(U)]C60 was < 2% in urine and feces at any 24 h time points. [14C(U)]C60 and [14C(U)]C60‐retinol were detected in liver of rats and together accounted for ~99% and ~56% of the total recovered at 1 and 30 days postexposure, respectively. The blood radioactivity at 1 h after [14C(U)]C60 exposure was fourfold higher in rats than in mice; blood radioactivity was still in circulation at 30 days post [14C(U)]C60 exposure in both species (
      PubDate: 2015-02-27T06:04:19.725928-05:
      DOI: 10.1002/jat.3110
       
  • The effect of Fe2O3 and ZnO nanoparticles on cytotoxicity and glucose
           metabolism in lung epithelial cells
    • Authors: Xiaofeng Lai; Yifang Wei, Hu Zhao, Suning Chen, Xin Bu, Fan Lu, Dingding Qu, Libo Yao, Jianyong Zheng, Jian Zhang
      Abstract: Metallic nanoparticles (NPs) have potential applications in industry and medicine, but they also have the potential to cause many chronic pulmonary diseases. Mechanisms for their cytotoxicity, glucose and energy metabolism responses need to be fully explained in lung epithelial cells after treatment with metallic nanoparticles. In our study, two different metallic nanoparticles (Fe2O3 and ZnO) and two cell‐based assays (BEAS‐2B and A549 cell lines) were used. Our findings demonstrate that ZnO nanoparticles, but not Fe2O3 nanoparticles, induce cell cycle arrest, cell apoptosis, reactive oxygen species (ROS) production, mitochondrial dysfunction and glucose metabolism perturbation, which are responsible for cytotoxicity. These results also suggest that the glucose metabolism and bioenergetics had a great potential in evaluating the cytotoxicity and thus were very helpful in understanding their underlying molecular mechanisms. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-02-27T05:37:21.369699-05:
      DOI: 10.1002/jat.3128
       
  • Sertoli cell as a model in male reproductive toxicology: Advantages and
           disadvantages
    • Authors: Mariana M. S. Reis; Ana C. Moreira, Mário Sousa, Premendu P. Mathur, Pedro F. Oliveira, Marco G. Alves
      Abstract: Pressure towards population aging in the demographic pyramid is not only due to sociological/personal choices but also due to subfertility or infertility. There are several chemicals and mixtures that impair male fertility. While experimental animal models are crucial to identify compounds that affect male fertility, it is essential to use reliable in vitro models to determine cellular targets and intracellular pathways that mediate chemical toxicity in the male reproductive system. In this review, we focused on the somatic Sertoli cell (SC) that, within the testis, is a major target for hormonal signaling and provides physical and nutritional support to developing germ cells. The different outcomes possible in each type of study: in vivo versus in vitro (either in primary or immortalized cell cultures) are analyzed. Herein, we intend to clarify the unique features that render SCs as excellent candidates for a robust in vitro model to study the deleterious effects of chemicals on male reproductive health. The sensitivity of SCs to toxicants/pharmaceuticals is discussed and, based on the literature reviewed we propose the in vitro study of SC physiology as a model to disclose deleterious effects of substances to male fertility. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-02-18T22:01:36.896633-05:
      DOI: 10.1002/jat.3122
       
  • The effect of a methyl‐deficient diet on the global DNA methylation
           and the DNA methylation regulatory pathways
    • Authors: Shota Takumi; Kazuyuki Okamura, Hiroyuki Yanagisawa, Tomoharu Sano, Yayoi Kobayashi, Keiko Nohara
      Abstract: Methyl‐deficient diets are known to induce various liver disorders, in which DNA methylation changes are implicated. Recent studies have clarified the existence of the active DNA demethylation pathways that start with oxidization of 5‐methylcytosine (5meC) to 5‐hydroxymethylcytosine by ten‐eleven translocation (Tet) enzymes, followed by the action of base–excision–repair pathways. Here, we investigated the effects of a methionine–choline‐deficient (MCD) diet on the hepatic DNA methylation of mice by precisely quantifying 5meC using a liquid chromatography–electrospray ionization–mass spectrometry and by investigating the regulatory pathways, including DNA demethylation. Although feeding the MCD diet for 1 week induced hepatic steatosis and lower level of the methyl donor S‐adenosylmethionine, it did not cause a significant reduction in the 5meC content. On the other hand, the MCD diet significantly upregulated the gene expression of the Tet enzymes, Tet2 and Tet3, and the base–excision–repair enzymes, thymine DNA glycosylase and apurinic/apyrimidinic‐endonuclease 1. At the same time, the gene expression of DNA methyltransferase 1 and a, was also significantly increased by the MCD diet. These results suggest that the DNA methylation level is precisely regulated even when dietary methyl donors are restricted. Methyl‐deficient diets are well known to induce oxidative stress and the oxidative‐stress‐induced DNA damage, 8‐hydroxy‐2′‐deoxyguanosine (8OHdG), is reported to inhibit DNA methylation. In this study, we also clarified that the increase in 8OHdG number per DNA by the MCD diet is approximately 10 000 times smaller than the reduction in 5meC number, suggesting the contribution of 8OHdG formation to DNA methylation would not be significant. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-02-17T19:31:53.091825-05:
      DOI: 10.1002/jat.3117
       
  • Heterozygous p53 knockout mouse model for dehydropyrrolizidine
           alkaloid‐induced carcinogenesis
    • Authors: Ammon W. Brown; Bryan L. Stegelmeier, Steven M. Colegate, Kip E. Panter, Edward L. Knoppel, Jeffery O. Hall
      Abstract: Dehydropyrrolizidine alkaloids (DHPA) are a large, structurally diverse group of plant‐derived protoxins that are potentially carcinogenic. With worldwide significance, these alkaloids can contaminate or be naturally present in the human food supply. To develop a small animal model that may be used to compare the carcinogenic potential of the various DHPAs, male heterozygous p53 knockout mice were administered a short‐term treatment of riddelliine 5, 15 or 45 mg kg–1 bodyweight day–1 by oral gavage for 14 days, or dosed a long‐term treatment of riddelliine 1 mg kg–1 bodyweight day–1 in pelleted feed for 12 months. Exposure to riddelliine increased the odds of tumor development in a dose‐responsive manner (odds ratio 2.05 and Wald 95% confidence limits between 1.2 and 3.4). The most common neoplastic process was hepatic hemangiosarcoma, which is consistent with published lifetime rodent riddelliine carcinogenesis studies. Angiectasis (peliosis hepatis) and other previously unreported lesions were also identified. The results of this research demonstrate the utility of the heterozygous p53 knockout mouse model for further investigation of comparative carcinogenesis of structurally and toxicologically different DHPAs and their N‐oxides. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.
      PubDate: 2015-02-17T19:17:03.837317-05:
      DOI: 10.1002/jat.3120
       
  • Involvement of mitogen‐activated protein kinase and NF‐κB
           signaling pathways in perfluorooctane sulfonic acid‐induced
           inflammatory reaction in BV2 microglial cells
    • Authors: Jingying Zhu; Wenyi Qian, Yixin Wang, Rong Gao, Jun Wang, Hang Xiao
      Abstract: Microglial activation is closely related to the pathogenesis of neurodegenerative diseases by producing proinflammatory cytokines. Perfluorooctane sulfonic acid (PFOS), known as an emerging persistent organic pollutant, is reported to disturb human immune homeostasis; however, whether it affects cytokine production or the immune response in the central nervous system remains unclear. The present study was aimed to explore whether PFOS contributed to inflammatory action and to investigate the corresponding mechanisms in BV2 microglia. PFOS‐mediated morphologic changes, cytokine responses and signaling events were examined by light microscopy, real‐time polymerase chain reaction, enzyme‐linked immunosorbent assay and Western blot assays. Our results indicated that PFOS increased BV2 cells activation and simultaneously increased tumor necrosis factor alpha and interleukin‐6 expression. In addition, the c‐Jun N‐terminal protein kinase inhibitor (SP600125), as well as ERK1/2 blocker (PD98059), transcriptionally at least, displayed anti‐inflammatory properties on PFOS‐elicited cytokine responses. Moreover, the inflammatory transcription factor NF‐κB was specifically activated by PFOS as well. These results, taken together, suggested that PFOS exerts its functional effects on the response of microglial cell activation via, in part, the c‐Jun N‐terminal protein kinase, ERK and NF‐κB signaling pathways with its subsequent influence on proinflammatory action. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-02-12T07:33:11.644658-05:
      DOI: 10.1002/jat.3119
       
  • Two‐generation reproduction and teratology studies of feeding
           aditoprim in Wistar rats
    • Authors: Xu Wang; Ziqiang Tan, Guyue Cheng, Ihsan Awais, Lingli Huang, Dongmei Chen, Yuanhu Pan, Zhenli Liu, Zonghui Yuan
      Abstract: Aditoprim, a new bacteriostatic agent that belongs to diaminopyrimidines, has a broad antimicrobial spectrum, good antibacterial activity and excellent pharmacokinetics. To evaluate the reproductive toxicity and teratogenic potential of aditoprim, different concentrations of aditoprim were administered to Wistar rats by feeding diets containing 0, 20, 100 and 1000 mg kg–1, respectively. Each group consisting of 18 males and 25 females (F0) was treated with different concentrations of aditoprim through a 13‐week period before mating and during mating, gestation, parturition and lactation. At weaning, 20 males and 25 females of the F1 generation weanlings per group were selected randomly as parents for the F2 generation. Selected F1 weanlings were exposed to the same diet and treatment as their parents. At 1000 mg kg–1 dose group, body weights in F0 and F1 rats, fetal body weight on day 21 (0, 4 and 21) after birth and number of viable fetuses in the F0 and F1 generation significantly decreased. Teratogenicity study was performed in combination with the F1 generation of a two‐generation reproduction study. F1 parents of the reproduction study were mated after weaning of the F2a pups. Pregnant female rats were subjected to cesarean section on gestational day 20 for teratogenic examination. At 1000 mg kg–1 group, body weights, fetal body lengths, tail lengths, litter weights and number of viable fetuses were significantly decreased. No obvious external, skeletal or visceral malformations in fetuses were noted in any groups in the teratogenic test. The no‐observed‐adverse‐effect level for reproduction/development toxicity of aditoprim was 100 mg kg–1 diet (about 7.89–9.25 mg kg–1 body weight day–1). Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-02-07T02:26:45.347717-05:
      DOI: 10.1002/jat.3121
       
  • Human bone morphogenetic protein‐7 does not counteract aristolochic
           acid‐induced renal toxicity
    • Authors: Marie‐Hélène Antoine; Frédéric Debelle, Julie Piccirilli, Fadoua El Kaddouri, Anne‐Emilie Declèves, Eric De Prez, Cécile Husson, Frédérique Mies, Marie‐Françoise Bourgeade, Joëlle L. Nortier
      Abstract: Aristolochic acids (AA) are nephrotoxic and profibrotic agents, leading to chronic kidney disease. As some controversial studies have reported a nephroprotective effect of exogenous recombinant human bone morphogenetic protein (rhBMP)‐7 in several models of renal fibrosis, we investigated the putative effect of rhBMP‐7 to prevent progressive tubulointerstitial damage after AA intoxication in vitro and in vivo. In vitro, the toxicity of AA on renal tubular cells was demonstrated by an increase in vimentin as well as a decrease in β‐catenin expressions, reflecting a dedifferentiation process. Increased fibronectin and interleukin‐6 levels were measured in the supernatants. Enhanced α‐SMA mRNA levels associated to decreased E‐cadherin mRNA levels were also measured. Incubation with rhBMP‐7 only prevented the increase in vimentin and the decrease in β‐catenin expressions. In vivo, in a rat model of AA nephropathy, severe tubulointerstitial lesions induced by AA after 10 and 35 days (collagen IV deposition and tubular atrophy), were not prevented by the rhBMP‐7 treatment. Similarly, rhBMP‐7 did not ameliorate the significant increase in urinary concentrations of transforming growth factor‐β. In summary, our in vitro data demonstrated a poor beneficial effect of rhBMP‐7 to reverse cell toxicity while, in vivo, there was no beneficial effect of rhBMP‐7. Therefore, further investigations are needed to confirm the exact role of BMP‐7 in progressive chronic kidney disease. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-02-07T01:38:35.977963-05:
      DOI: 10.1002/jat.3116
       
  • Bisphenol A promotes X‐linked inhibitor of apoptosis
           protein‐dependent angiogenesis via G protein‐coupled estrogen
           receptor pathway
    • Authors: Jian Liu; Xin Jin, Nana Zhao, Xiaolei Ye, Chenjiang Ying
      Abstract: Bisphenol A (BPA), one of the high‐volume chemicals worldwide, has a core structure resembling that of natural estradiol. Recent evidence has demonstrated that exposure to BPA has a relationship with the risk of cancer. The objective of our study is to investigate the mechanisms underlying the pro‐angiogenic effects of BPA. We demonstrated that BPA markedly induces endothelial cell proliferation, migration and tube formation by activating endothelial nitric oxide synthase. BPA‐induced nitric oxide generation appeared to be associated with the X‐linked inhibitor of apoptosis protein (XIAP), which competes with endothelial nitric oxide synthase for caveolin‐1. BPA was shown to exert its pro‐angiogenic effect by upregulating XIAP expression via G protein‐coupled estrogen receptor (ER) activation but not via ERα or ERβ. Our data suggest that 100 nM BPA promote angiogenesis in a G protein‐coupled ER‐dependent genomic pathway, and provide a novel insight into the potential role of XIAP in mediating the pro‐angiogenic effects of BPA in endothelial cells. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-02-07T01:22:35.541079-05:
      DOI: 10.1002/jat.3112
       
  • Safety assessment of aditoprim acute, subchronic toxicity and mutagenicity
           studies
    • Authors: Xu Wang; Ziqiang Tan, Yuanhu Pan, Awais Ihsan, Qianying Liu, Lingli Huang, Guyue Cheng, Dongmei Chen, Yanfei Tao, Zhenli Liu, Zonghui Yuan
      Abstract: Aditoprim (ADP), a new developed dihydrofolate reductase (DHFR) inhibitor, has great potential in clinical veterinary medicine because of its greater pharmacokinetic properties than structural analogs. Preclinical toxicology studies were performed to assess the safety of ADP including an acute oral toxicity test, a subchronic toxicity test and five mutagenicity tests. In the acute oral toxicity test, ADP was administered singly by oral gavage to Wistar rats and Kunming mice. The LD50 calculated was 1400 mg kg–1 body weight (BW) day–1 in rats and 1130 mg kg–1 BW day–1 in mice. In a subchronic study, Wistar rats were administered ADP at dose levels of 0, 20, 100 and 1000 mg kg–1 diet for 90 days. Significant decreases were observed on body weight and food efficiency in the high‐dose group. Treatment‐related changes in clinical serum biochemistry were found in the medium‐ and high‐dose groups. Significant increases in the relative weights of livers and kidneys in females and testis in males in the 1000 mg kg–1 diet, and significant decrease in relative weights of livers in males in the 100 mg kg–1 diet were noted. Histopathological observations revealed that the 1000 mg kg–1 ADP diet could induce lymphocytic infiltration and hepatocytic necrosis near the hepatic portal area. The genotoxicity of ADP was negative in tests, such as the bacterial reverse mutation assay, mice bone marrow erythrocyte micronucleus assay, in vitro chromosomal aberration test, in vitro cho/hgprt mammalian cell mutagenesis assay and mice testicle cells chromosome aberration. Based on the subchronic study, the no‐observed‐adverse‐effect level for ADP was a 20 mg kg–1 diet, which is about 1.44‐1.53 mg kg–1 BW day–1 in rats. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-02-07T00:21:09.972171-05:
      DOI: 10.1002/jat.3107
       
  • Comparative cytotoxicity of dolomite nanoparticles in human larynx HEp2
           and liver HepG2 cells
    • Authors: Maqusood Ahamed; Hisham A. Alhadlaq, Javed Ahmad, Maqsood A. Siddiqui, Shams T. Khan, Javed Musarrat, Abdulaziz A. Al‐Khedhairy
      Abstract: Dolomite is a natural mineral of great industrial and commercial importance. With the advent of nanotechnology, natural minerals including dolomite in the form of nanoparticles (NPs) are being utilized in various applications to improve the quality of products. However, safety or toxicity information of dolomite NPs is largely lacking. This study evaluated the cytotoxicity of dolomite NPs in two widely used in vitro cell culture models: human airway epithelial (HEp2) and human liver (HepG2) cells. Concentration‐dependent decreased cell viability and damaged cell membrane integrity revealed the cytotoxicity of dolomite NPs. We further observed that dolomite NPs induce oxidative stress in a concentration‐dependent manner, as indicated by depletion of glutathione and induction of reactive oxygen species (ROS) and lipid peroxidation. Quantitative real‐time PCR data demonstrated that the mRNA level of tumor suppressor gene p53 and apoptotic genes (bax, CASP3 and CASP9) were up‐regulated whereas the anti‐apoptotic gene bcl‐2 was down‐regulated in HEp2 and HepG2 cells exposed to dolomite NPs. Moreover, the activity of apoptotic enzymes (caspase‐3 and caspase‐9) was also higher in both kinds of cells treated with dolomite NPs. It is also worth mentioning that HEp2 cells seem to be marginally more susceptible to dolomite NPs exposure than HepG2 cells. Cytotoxicity induced by dolomite NPs was efficiently prevented by N‐acetyl cysteine treatment, which suggests that oxidative stress is primarily responsible for the cytotoxicity of dolomite NPs in both HEp2 and HepG2 cells. Toxicity mechanisms of dolomite NPs warrant further investigations at the in vivo level. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-02-06T23:47:14.312666-05:
      DOI: 10.1002/jat.3097
       
  • Are zebrafish larvae suitable for assessing the hepatotoxicity potential
           of drug candidates?
    • Authors: Natalie Mesens; Alexander D. Crawford, Aswin Menke, Pham Duc Hung, Freddy Van Goethem, Rik Nuyts, Erik Hansen, Andre Wolterbeek, Jacky Van Gompel, Peter De Witte, Camila V. Esguerra
      Abstract: Drug‐induced liver injury (DILI) is poorly predicted by single‐cell‐based assays, probably because of the lack of physiological interactions with other cells within the liver. An intact whole liver system such as one present in zebrafish larvae could provide added value in a screening strategy for DILI; however, the possible occurrence of other organ toxicities and the immature larval stage of the zebrafish might complicate accurate and fast analysis. We investigated whether expression analysis of liver‐specific fatty acid binding protein 10a (lfabp10a) was an appropriate endpoint for assessing hepatotoxic effects in zebrafish larvae. It was found that expression analysis of lfabp10a was a valid marker, as after treatment with hepatotoxicants, dose–response curves could be obtained and statistically significant abnormal lfabp10 expression levels correlated with hepatocellular histopathological changes in the liver. However, toxicity in other vital organs such as the heart could impact liver outgrowth and thus had to be assessed concurrently. Whether zebrafish larvae were suitable for assessing human relevant drug‐induced hepatotoxicity was assessed with hepatotoxicants and non‐hepatotoxicants that have been marketed for human use and classified according to their mechanism of toxicity. The zebrafish larva showed promising predictivity towards a number of mechanisms and was capable of distinguishing between hepatotoxic and non‐hepatotoxic chemical analogues, thus implying its applicability as a potential screening model for DILI. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-02-06T22:52:02.514727-05:
      DOI: 10.1002/jat.3091
       
  • Bupropion treatment increases epididymal contractility and impairs sperm
           
    • Authors: Marilia Martins Cavariani; Luiz Ricardo Almeida Kiguti, Josiane Lima Rosa, Gabriel Adan Araújo Leite, Patrícia Villela e Silva, André Sampaio Pupo, Wilma De Grava Kempinas
      Abstract: Bupropion is a dopamine (DA) and norepinephrine (NE) reuptake inhibitor used as smoking cessation and antidepressant drug with a lower incidence of male sexual dysfunction. We showed previously that sibutramine, a norepinephrine/serotonine reuptake inhibitor, reduced male rat fertility. As there are no studies evaluating the impact of bupropion treatment on spermatic parameters and male fertility, we evaluated the effects of bupropion treatment (15 and 30 mg kg−1, 30 days) on sexual behavior, spermatic parameters and fertility of male Wistar rats and on the epididymal duct in vitro contractility. Bupropion 15 mg kg−1 increased the serum luteinizing hormone level and the epididymal duct contractility, but the sperm quality was not affected. At 30 mg kg−1 bupropion impaired sperm quality increasing the incidence of non‐progressive sperm. The male sexual behavior and fertility were not modified at both bupropion doses. These results, in rats, suggest the importance of studies evaluating the effects of bupropion on the human male sperm quality. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-02-02T20:20:56.934592-05:
      DOI: 10.1002/jat.3089
       
  • Molecular mechanisms of human thyrocyte dysfunction induced by low
           concentrations of polychlorinated biphenyl 118 through the Akt/FoxO3a/NIS
           pathway
    • Authors: Hongwei Guo; Hui Yang, Huanhuan Chen, Wen Li, Jinmei Tang, Pei Cheng, Yuchun Xie, Yun Liu, Guoxian Ding, Dai Cui, Xuqin Zheng, Yu Duan
      Abstract: Polychlorinated biphenyls (PCBs) are typical persistent organic pollutants that can interfere with multiple organ systems of humans. Previously, we concluded that persistent exposure to low doses of PCB118 could severely damage the thyroidal structure, dramatically decrease the concentration of serum thyroid hormones and inhibit the pivotal gene expressions such as sodium/iodide symporter (NIS) and thyroglobulin (Tg). To explore the molecular mechanisms of thyrocyte dysfunction induced by 2,3′,4,4′,5‐pentachlorobiphenyl (PCB118), monolayer cultured human thyroid epithelial cells (HTECs) were treated with PCB118 or dimethyl sulfoxide (DMSO) as a control. Our results indicated that relatively higher concentrations of PCB118 could induce a loss in the viability of HTEC. In cultures with concentrations of PCB118 from 0.025 to 25 nM, which did not affect cell viability or apoptosis, concentrations of Tg and thyroxine (T4) were significantly decreased compared with those in the controls. In addition, mRNA and protein levels of Akt were increased significantly in the PCB118‐treated groups, whereas FoxO3a expression did not show particular variation. Furthermore, exposure to PCB118 was associated with a significant increase of the protein levels of p‐Akt and p‐FoxO3a, and these effects were blocked by LY294002. In contrast, mRNA and protein expression levels of NIS were decreased significantly, and this effect was blocked by LY294002. Unlike control cells, a cytoplasmic shift of FoxO3a was observed in the PCB118‐treated group. Our research suggests that PCB118 may induce thyrocyte dysfunction through the Akt/FoxO3a/NIS signalling pathway, which provides potential new insights for finding interventions to counteract the damage to the human body caused by PCBs. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-02-02T19:57:38.986114-05:
      DOI: 10.1002/jat.3032
       
  • Different cytotoxicity responses to antimicrobial nanosilver coatings when
           comparing extract‐based and direct‐contact assays
    • Authors: Eric M. Sussman; Brendan J. Casey, Debargh Dutta, Benita J. Dair
      Abstract: This study was performed to understand how the choice of cytotoxicity assay format affects the observed biocompatibility of nanosilver (nAg). nAg coatings are physical coatings containing silver (Ag) that have feature sizes of 100 nm or less, often in the form of nanoparticles or grains. They are used on medical devices to prevent infection, but in spite of this intended benefit, observations of potential cytotoxicity from nAg have been reported in numerous published studies. For medical device regulation, cytotoxicity testing is part of a biocompatibility evaluation, in which specific test methods are chosen based on the technological characteristics and intended use of a device. For this study, nAg‐coated tissue culture polystyrene surfaces were prepared using magnetron sputter coating, resulting in nAg films of 0.2 to 311 µg cm−2 Ag. These coatings exhibited nanometer‐scale morphologies and demonstrated a > 4log10 reduction in Escherichia coli viability. It was observed that extracts of nAg caused no cytotoxicity to L929 mouse fibroblasts, but cells cultured directly on nAg coatings (direct‐contact assay format) showed a dose‐dependent reduction in viability by up to 100% (P 
      PubDate: 2015-02-02T18:51:12.25067-05:0
      DOI: 10.1002/jat.3104
       
  • Effects of cylindrospermopsin on the phagocytic cells of the common carp
           (Cyprinus carpio L.)
    • Authors: Anna Sieroslawska; Anna Rymuszka, Łukasz Adaszek
      Abstract: Cylindrospermopsin is a cyanotoxin with cytotoxic activity. It is released into water during and after cyanobacterial water blooms and thus poses a threat to the health of fish. There is very little information available concerning the effects of the toxin on fish immune cells. In this study, we assessed the potential impact of cylindrospermopsin on the basic functions of phagocytic cells from common carp (Cyprinus carpio L.), including phagocytosis, reactive oxygen and nitrogen species production, and the structure of microfilaments and selected cytokine expression. Phagocytic cells, isolated from fish head kidneys, were exposed to the toxin at concentrations of 0.05, 0.1, 0.5 or 1 µg ml−1, for up to 24 h. Cytotoxicity, detected by lactate dehydrogenase release, was observed at the highest studied concentration. A decrease in phagocytic activity and changes in actin cytoskeletal structures were observed after the cell exposure to the toxin at 0.5 and 1 µg ml−1. Moreover, at all tested concentrations, cylindrospermopsin increased the production of reactive oxygen and nitrogen species. It also evidently influenced the expression of genes of proinflammatory cytokines interleukin‐1β and tumour necrosis factor‐α and, to a minor extent, anti‐inflammatory transforming growth factor‐β, but had no effects on interleukin‐10. The results indicated that the cyanotoxin cylindrospermopsin is able to modify basic features of carp phagocytic cells, which might result in adverse consequences for fish health. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-01-29T08:58:37.744329-05:
      DOI: 10.1002/jat.3118
       
  • The relationship between Cd‐induced autophagy and lysosomal
           activation in WRL‐68 cells
    • Authors: Su‐Fang Meng; Wei‐Ping Mao, Fang Wang, Xiao‐Qian Liu, Luan‐Luan Shao
      Abstract: This study shows that Cd induces autophagy in the human's embryonic normal liver cell line (WRL‐68). The expression of LC3B‐II and the mature cathepsin L were analyzed by Western blotting. The autophagosomes and lysosomes were directly visualized by electron microscopy and confocal microscopy analysis in Cd‐exposed WRL‐68 cells. In this study, we first found that autophagy induced the activation of lysosomal function in WRL‐68 cells. The lysosomal activation was markedly decreased when the cells were co‐treated with 3‐MA (an inhibitor of autophagy). Secondly, we provided the evidence that the activation of lysosomal function depended on autophagosome–lysosome fusion. The colocalization of lysosome‐associated membrane protein‐2 (LAMP2) and GFP‐LC3 was significantly reduced, when they were treated with thapsigargin (an inhibitor of autophagosome–lysosome fusion). We demonstrated that deletion or blockage of the autophagosome–lysosome fusion process effectively diminished lysosomal activation, which suggests that lysosomal activation occurring in the course of autophagy is dependent on autophagosome–lysosome fusion. Thirdly, we provided evidence that the activation of lysosomal function was associated with lysosomal acid. We investigated the relationship between autophagosome–lysosome fusion and pH in acidic compartments by visualizing fusion process in WRL‐68 cells. This suggests that increasing pH in acidic compartments in WRL‐68 cells inhibits the autophagosome–lysosome fusion. Finally, we found that the activation of lysosomal function was associated with Ca2+ stores and the intracellular Ca2+ channels or pumps were possibly pH‐dependent. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-01-29T08:46:15.013806-05:
      DOI: 10.1002/jat.3114
       
  • Bisphenol A exposure induces metabolic disorders and enhances
           atherosclerosis in hyperlipidemic rabbits
    • Authors: Chao Fang; Bo Ning, Ahmed Bilal Waqar, Manabu Niimi, Shen Li, Kaneo Satoh, Masashi Shiomi, Ting Ye, Sijun Dong, Jianglin Fan
      Abstract: Bisphenol A (BPA) is an artificial environmental endocrine disrupter. Excess exposure to BPA may induce many disorders in the metabolism and cardiovascular system. However, the underlying toxicological mechanisms remain largely unknown. In this study, we administered genetically hyperlipidemic Watanabe heritable hyperlipidemic (WHHL‐MI) rabbits (male, 14 week old), which have more common features with humans than the mouse and rat especially in the metabolism and cardiovascular system, with BPA at 40 mg kg–1 day–1 for 8 weeks by gavage and compared their plasma lipids, glucose and insulin response with those of the vehicle group. All of the rabbits were sacrificed, and their pancreas, liver, adipose tissue, heart and aorta were analyzed using histological and morphometric methods. Furthermore, we treated human hepatoma HepG2 cells and human umbilical cord vein endothelial cells (HUVECs), with different doses of BPA based on the serum BPA levels in the WHHL rabbits for 6 h to investigate the possible molecular mechanisms. Our results showed that BPA‐treated rabbits showed insulin resistance, prominent adipose accumulation and hepatic steatosis. Additionally, BPA exposure also caused myocardial injury and enhanced the development of atherosclerosis in the aortic arch with increased macrophage number (86%) and advanced lesion areas (69%). Increased expression of inflammatory genes found in the liver of BPA‐treated rabbits along with the up‐regulation of ER stress, lipid and glucose homeostasis and inflammatory genes in the cultured HepG2 cells and HUVECs suggest that BPA may induce metabolic disorders and enhance atherosclerosis through regulating above molecular pathways in the liver and endothelium. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-01-23T13:24:22.578133-05:
      DOI: 10.1002/jat.3103
       
  • Effects of homocysteine on mesenchymal cell proliferation and
           differentiation during chondrogenesis on limb development
    • Authors: Gilian Fernando Bourckhardt; Manuela Sozo Cecchini, Dib Ammar, Karoline Kobus‐Bianchini, Yara Maria Rauh Müller, Evelise Maria Nazari
      Abstract: High levels of homocysteine (Hcy) are related to an increased risk of the occurrence of congenital anomalies, including limb defects. However, few evaluations about how toxic levels of Hcy affect limb development have been reported. We investigated whether Hcy can affect the cell cycle proteins and proteins involved in mesenchymal cell differentiation during limb development, in a chicken embryo model. Embryos were treated with 20 µmol d‐l Hcy/50 µl saline at embryonic day 2 and analyzed at embryonic day 6. Untreated control embryos received exclusively 50 µl saline solution. To identify cells in proliferation and cell cycle proteins, as well as Pax1/9 and Sox9 proteins, we performed immunolocalization and flow cytometry analyses using the antibodies anti‐phosphohistone H3, anti‐p53, anti‐p21, anti‐proliferating cell nuclear antigen, anti‐Pax1, anti‐Pax9 and anti‐Sox9. No significant differences in cell proliferation were observed between Hcy‐treated and untreated embryos. We observed a decrease of the proliferating cell nuclear antigen and p21 proteins, both involved in the G1 phase of cell cycle progression. On the other hand, in mesenchymal cells of the limbs, Hcy induces an increase of p53 protein, which can be activated by DNA damage. In cell differentiation, Hcy induced an increase mainly of Pax9 and Sox9 proteins. Our data indicate that the treatment with Hcy changes the mesenchymal cell dynamics during limb development, but does not change the morphology of the cartilage molds. These findings provide information to understand better the cellular basis of the toxicity of Hcy on chondrogenesis during limb development. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-01-23T12:15:56.210643-05:
      DOI: 10.1002/jat.3111
       
  • Quantitative evaluation of the pulmonary microdistribution of TiO2
           nanoparticles using X‐ray fluorescence microscopy after
           intratracheal administration with a microsprayer in rats
    • Authors: Guihua Zhang; Naohide Shinohara, Hirokazu Kano, Hideki Senoh, Masaaki Suzuki, Takeshi Sasaki, Shoji Fukushima, Masashi Gamo
      Abstract: The unevenness of pulmonary nanoparticle (NP) distribution, which hinders the establishment of an absolute dose–response relationship, has been described as one of the limitations of intratracheal administration techniques for toxicological assessment of inhaled NPs. Quantification of the NP microdistribution would facilitate the establishment of a concentration–response relationship in localized regions of the lung; however, such quantitative methods have not been reported. Here, we established a quantitative method for evaluating pulmonary TiO2 NP microdistribution in rats using X‐ray fluorescence microscopy. Ti intensity in lung sections from rats intratracheally administered 10 mg kg–1 TiO2 NPs with a microsprayer was measured using X‐ray fluorescence with a 100 µm beam size. Ti reference samples were prepared by dropping different concentrations of Ti solutions on glass slide or lung sections of untreated rat. Ti intensity increased linearly with Ti content in the reference samples on both substrates. The detection limit of TiO2 was estimated to be 6.3 ng mm–2. The reproducibility was confirmed for measurements done in the short‐ (2 weeks) and long‐term (6 months). The quantitative results of TiO2 NP microdistribution suggested that more TiO2 NPs were distributed in the right caudal and accessory lobes, which are located downstream of the administration direction of the NP suspension, and the lower portion of each lobe. The detection rates of TiO2 NPs were 16.6–25.0%, 5.19–15.6%, 28.6–39.2%, 21.4–38.7% and 10.6–23.2% for lung sections from the right cranial, middle, caudal, accessory and left lobes, respectively. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-01-23T11:49:20.327102-05:
      DOI: 10.1002/jat.3109
       
  • Endocrine‐disrupting potentials of equine estrogens equilin,
           equilenin, and their metabolites, in the medaka Oryzias latipes: in silico
           and DNA microarray studies
    • Authors: Masaya Uchida; Hiroshi Ishibashi, Ryoko Yamamoto, Akiko Koyanagi, Teruhiko Kusano, Nobuaki Tominaga, Yasuhiro Ishibashi, Koji Arizono
      Abstract: Although several previous studies have demonstrated the presence of equine estrogens in the aquatic environment, limited data are currently available on the endocrine‐disrupting potentials in fish and the risks they pose to aquatic organisms. To investigate the interactions of major equine estrogens equilin (Eq) and equilenin (Eqn), as well as their metabolites 17α‐dihydroequilin, 17β‐dihydroequilin, 17α‐dihydroequilenin and 17β‐dihydroequilenin, with the estrogen receptor α (ERα) of medaka (Oryzias latipes), a three‐dimensional model of the ligand‐binding domain (LBD) of ERα was built in silico, and docking simulations were performed. The docking simulation analysis indicated that the interaction of 17β‐dihydroequilenin with the ERα LBD is the most potent, followed by those of 17α‐dihydroequilin and 17β‐dihydroequilin, whereas those of Eq and Eqn were least potent. We further analyzed gene expression profiles in the livers of male medaka exposed to Eq and Eqn. A DNA microarray representing 6000 genes revealed that 24‐h exposure to Eq and Eqn (100 ng/L) upregulated the expression of 6 and 34 genes in the livers of males, respectively. Genes upregulated by Eq included the estrogenic biomarker genes vitellogenins and choriogenins, suggesting the estrogenic potential of Eq. In contrast, Eqn exposure upregulated several cancer‐related genes, such as mediator complex subunit 16 and RAS oncogene family members, suggesting a carcinogenic potential for Eqn. These results suggest that equine estrogens may have not only endocrine‐disrupting potentials via the ERα signaling pathway but also carcinogenic potency in male medaka. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-01-22T00:34:36.505314-05:
      DOI: 10.1002/jat.3098
       
  • Effects of lithium on growth, maturation, reproduction and gene expression
           in the nematode Caenorhabditis elegans
    • Authors: Ayako Inokuchi; Ryoko Yamamoto, Fumiyo Morita, Shota Takumi, Hiromi Matsusaki, Hiroshi Ishibashi, Nobuaki Tominaga, Koji Arizono
      Abstract: Lithium (Li) has been widely used to treat bipolar disorder, and industrial use of Li has been increasing; thus, environmental pollution and ecological impacts of Li have become a concern. This study was conducted to clarify the potential biological effects of LiCl and Li2CO3 on a nematode, Caenorhabditis elegans as a model system for evaluating soil contaminated with Li. Exposure of C. elegans to LiCl and Li2CO3 decreased growth/maturation and reproduction. The lowest observed effect concentrations for growth, maturation and reproduction were 1250, 313 and 10 000 µm, respectively, for LiCl and 750, 750 and 3000 µm, respectively, for Li2CO3. We also investigated the physiological function of LiCl and LiCO3 in C. elegans using DNA microarray analysis as an eco‐toxicogenomic approach. Among approximately 300 unique genes, including metabolic genes, the exposure to 78 µm LiCl downregulated the expression of 36 cytochrome P450, 16 ABC transporter, 10 glutathione S‐transferase, 16 lipid metabolism and two vitellogenin genes. On the other hand, exposure to 375 µm Li2CO3 downregulated the expression of 11 cytochrome P450, 13 ABC transporter, 13 lipid metabolism and one vitellogenin genes. No gene was upregulated by LiCl or Li2CO3. These results suggest that LiCl and Li2CO3 potentially affect the biological and physiological function in C. elegans associated with alteration of the gene expression such as metabolic genes. Our data also provide experimental support for the utility of toxicogenomics by integrating gene expression profiling into a toxicological study of an environmentally important organism such as C. elegans. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-01-21T22:52:27.326537-05:
      DOI: 10.1002/jat.3058
       
  • Cytotoxicity of luteolin in primary rat hepatocytes: the role of
           CYP3A‐mediated ortho‐benzoquinone metabolite formation and
           glutathione depletion
    • Authors: Fuguo Shi; Peng Zhao, Xiaobing Li, Hong Pan, Shiping Ma, Li Ding
      Abstract: Luteolin (LUT), an active ingredient in traditional Chinese medicines and an integral part of the human diet, has shown promising pharmacological activities with a great potential for clinical use. The purpose of this study was to evaluate the role of cytochrome P450 (CYP450)‐mediated reactive ortho‐benzoquinone metabolites formation and glutathione (GSH) depletion in LUT‐induced cytotoxicity in primary rat hepatocytes. A reactive ortho‐benzoquinone metabolite was identified by liquid chromatography coupled with tandem mass spectrometry (LC‐MS/MS) in rat liver microsomes (RLMs) and rat hepatocytes. Using a specific chemical inhibitor method, the CYP3A subfamily was found to be responsible for the reactive metabolite formation in RLMs. Induction of CYP3A by dexamethasone enhanced LUT‐induced cytotoxicity, whereas inhibition of CYP3A by ketoconazole (Keto) decreased the cytotoxicity. The cytotoxicity and cell apoptosis induced by LUT were related to the amount of reactive metabolite formation. Furthermore, Keto inhibited the LUT‐induced GSH exhaustion. The cytotoxicity was significantly enhanced by pretreatment with L‐buthionine sulfoximine to deplete the intracellular GSH. A time course experiment showed that GSH depletion by LUT was not via oxidation of GSH and occurred prior to the increase in 2', 7'‐dichlorofluorescein in hepatocytes. Collectively, these data suggest that CYP3A‐mediated reactive metabolite formation plays a critical role in LUT‐induced hepatotoxicity, and the direct GSH depletion is an initiating event in LUT‐mediated cytotoxicity in primary rat hepatocytes. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-01-21T22:30:19.0298-05:00
      DOI: 10.1002/jat.3106
       
  • Genomic and gene expression responses to genotoxic stress in PAC2
           zebrafish embryonic cell line
    • Authors: Maja Šrut; Jean‐Paul Bourdineaud, Anamaria Štambuk, Göran I. V. Klobučar
      Abstract: PAC2 cell line is, along most of the developed zebrafish cell lines, poorly characterized concerning its response to genotoxicants. To define the PAC2 cell line response to different forms of genotoxic stress, we exposed the cells to model genotoxic agents (benzo[a]pyrene, B[a]P, and ethyl methanesulfonate) and subsequently monitored DNA damage and alterations by using the battery of tests, including the Comet assay, quantitative random‐amplified polymorphic DNA and amplified fragment length polymorphism. The expression of several DNA repair (xpc, xpd, hr23b, rad51, msh2) and oxidative stress response (sod (Cu/Zn)) genes was monitored as well. To obtain an indication of the PAC2 cell line metabolizing capacity, the expression of genes belonging to cyp1, cyp2 and cyp3 families was assessed upon exposure to B[a]P. Genotoxic responses were observed in all the used methods, and quantitative random‐amplified polymorphic DNA and amplified fragment length polymorphism proved to be more sensitive by revealing DNA alterations even when the Comet assay indicated lack of significant damage. The PAC2 cell line demonstrated basal and B[a]P‐induced expression of several cyp genes, suggesting its ability to metabolize indirect acting xenobiotics to a certain point. Based on these results, PAC2 cells seem to be sensitive zebrafish in vitro model in the genotoxicity assessment of the direct acting genotoxicant; however, they are less sensitive toward the indirect acting genotoxicant due to their limited metabolizing properties. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-01-21T22:16:15.203856-05:
      DOI: 10.1002/jat.3113
       
  • Toxicity of cobalt–chromium nanoparticles released from a
           resurfacing hip implant and cobalt ions on primary human lymphocytes in
           vitro
    • Authors: Olga M. Posada; R. J. Tate, M. H. Grant
      Abstract: Adverse tissue responses to prostheses wear particles and released ions are important contributors to hip implant failure. In implant‐related adverse reactions T‐lymphocytes play a prominent role in sustaining the chronic inflammatory response. To further understand the involvement of lymphocytes in metal‐on‐metal (MoM) implant failure, primary human lymphocytes were isolated and treated with cobalt–chromium (Co‐Cr) wear debris and Co ions, individually, and in combination, for 24, 48 and 120 h. There was a significant increase in cell number where debris was present, as measured by the Neutral Red assay. Interleukin‐6 (IL‐6), interferon‐γ (IFN‐γ) and tumour necrosis factor‐α (TNF‐α) secretion levels significantly decreased in the presence of metal particles, as measured by ELISA. Interleukin‐2 (IL‐2) secretion levels were significantly decreased by both debris and Co ions. Flow cytometry analysis showed that the metal nanoparticles induced a significant increase in apoptosis after 48‐h exposure. This investigation showed that prolonged exposure (120 h) to metal debris induces lymphocyte proliferation, suggesting that activation of resting lymphocytes may have occurred. Although cytokine production was affected mainly by metal debris, cobalt toxicity may also modulate IL‐2 secretion, and even Co ion concentrations below the MHRA guideline levels (7 ppb) may contribute to the impairment of immune regulation in vivo in patients with MoM implants. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-01-21T21:31:14.028782-05:
      DOI: 10.1002/jat.3100
       
  • Cobalt oxide nanoparticles induced oxidative stress linked to activation
           of TNF‐α/caspase‐8/p38‐MAPK signaling in human
           leukemia cells
    • Authors: Sourav Chattopadhyay; Sandeep Kumar Dash, Satyajit Tripathy, Balaram Das, Santanu Kar Mahapatra, Panchanan Pramanik, Somenath Roy
      Abstract: The purpose of this study was to determine the intracellular signaling transduction pathways involved in oxidative stress induced by nanoparticles in cancer cells. Activation of reactive oxygen species (ROS) has some therapeutic benefits in arresting the growth of cancer cells. Cobalt oxide nanoparticles (CoO NPs) are an interesting compound for oxidative cancer therapy. Our results showed that CoO NPs elicited a significant (P
      PubDate: 2015-01-11T19:52:09.170136-05:
      DOI: 10.1002/jat.3080
       
  • Quantitative toxicoproteomic analysis of zebrafish embryos exposed to a
           retinoid X receptor antagonist UVI3003
    • Authors: Liang Zheng; Jianlan Yu, Huahong Shi, Liang Xia, Qi Xin, Qiang Zhang, Heng Zhao, Ji Luo, Wenhai Jin, Daoji Li, Junliang Zhou
      Abstract: Retinoid X receptor (RXR) antagonists, including some environmental endocrine disruptors, have a teratogenic effect on vertebrate embryos. To investigate the toxicological mechanism on the protein expression level, a quantitative proteomic study was conducted to analyze the proteome alterations of zebrafish (Danio rerio) embryos exposed to gradient concentrations of a representative RXR antagonist UVI3003. Using isobaric Tags for Relative and Absolute Quantitation (iTRAQ) labeling coupled nano high‐performance liquid chromatography‐tandem mass spectrometry (nano HPLC‐MS/MS), in total 6592 proteins were identified, among which 195 proteins were found to be differentially expressed by more than a two‐fold change in exposed groups compared with the control. Gene ontology analysis showed that these differential proteins were mostly involved in anatomical structure development, biosynthetic process, ion binding and oxidoreductase activity. Moreover, the biological pathways of translation, lipoprotein metabolism, cell survival and gluconeogenesis were intensively inhibited after exposure. Some significantly downregulated proteins such as apolipoprotein A‐I and vitellogenin and upregulated proteins such as calcium activated nucleotidase 1b, glutathione S‐transferase and glucose 6‐dehydrogenases showed a strong dose‐dependent response. The results provided new insight into the molecular details of RXR antagonist‐induced teratogenicity and added novel information of pathways and potential biomarkers for evaluation of RXR interfering activity. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-01-11T19:41:31.661922-05:
      DOI: 10.1002/jat.3099
       
  • The toxicity and distribution of iron oxide–zinc oxide
           core‐shell nanoparticles in C57BL/6 mice after repeated subcutaneous
           administration
    • Authors: Jun‐Won Yun; Jung‐Hee Yoon, Byeong‐Cheol Kang, Nam‐Hyuk Cho, Seung Hyeok Seok, Seung‐Kee Min, Ji Hyun Min, Jeong‐Hwan Che, Young Keun Kim
      Abstract: Therapeutic cancer vaccines promote immune responses by delivering tumour‐specific antigens. Recently, we developed iron oxide (Fe3O4)–zinc oxide (ZnO) core‐shell nanoparticles (CSNPs) as carriers for antigen delivery into dendritic cells (DCs), and the CSNPs were injected subcutaneously into C57BL/6 mice to examine the systemic toxicity, tissue distribution and excretion of the CSNPs. The doses injected were 0, 4, 20 and 200 mg kg–1 weekly for 4 weeks. No significant changes were observed after the CSNPs administration with respect to mortality, clinical observations, body weight, food intake, water consumption, urinalysis, haematology, serum biochemistry,and organ weights. A dose‐dependent increase in granulomatous inflammation was observed at the injection site of the CSNP‐treated animals, but no other histopathological lesions in other organs could be attributed to the CSNPs. The Zn concentration, which is an indicator for CSNPs, was not significantly higher in the sampled tissues, urine, or faeces after the CSNP injection. In contrast, the Zn concentration at the subcutaneous skin of the site injected with the CSNPs increased in a dose‐dependent manner, along with a macroscopic deposition of the CSNPs. The CSNP residue at the injection site resulted in a foreign body response with the appearance of macrophage infiltration, but otherwise did not show any systemic distribution or toxicity at up to 200 mg kg–1 during this study. In conclusion, CSNPs could be used as good antigen carriers for DC‐based immunotherapy, although further study is needed to completely clear the residue of the CSNPs at the injection site. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-01-08T20:58:03.730817-05:
      DOI: 10.1002/jat.3102
       
  • Enhanced QSAR models for drug‐triggered inhibition of the main
           cardiac ion currents
    • Authors: Barbara Wiśniowska; Aleksander Mendyk, Jakub Szlęk, Michał Kołaczkowski, Sebastian Polak
      Abstract: The currently changing cardiac safety testing paradigm suggests, among other things, a shift towards using in silico models of cellular electrophysiology and assessment of a concomitant block of multiple ion channels. In this study, a set of four enhanced QSAR models have been developed: for the rapid delayed rectifying potassium current (IKr), slow delayed rectifying potassium current (IKs), peak sodium current (INa) and late calcium current (ICaL), predicting ion currents changes for the specific in vitro experiment from the 2D structure of the compounds. The models are a combination of both in vitro study parameters and physico‐chemical descriptors, which is a novel approach in drug–ion channels interactions modeling. Their predictive power assessed in the enhanced, more demanding than standard procedure, 10‐fold cross validation was reasonably high. Rough comparison with published pure in silico hERG interaction models shows that the quality of the model predictions does not differ from other models available in the public domain, however, it takes its advantage in accounting for inter‐experimental settings variability. Developed models are implemented in the Cardiac Safety Simulator, a commercially available platform enabling the in vitro–in vivo extrapolation of the drugs proarrhythmic effect and ECG simulation. A more comprehensive assessment of the effects of the compounds on ion channels allows for making more informed decisions regarding the risk – and thus avoidance – of exclusion of potentially safe and effective drugs. Copyright © 2015 John Wiley & Sons, Ltd.
      PubDate: 2015-01-05T20:26:17.842509-05:
      DOI: 10.1002/jat.3095
       
  • Tl(I) and Tl(III) alter the expression of EGF‐dependent signals and
           cyclins required for pheochromocytoma (PC12) cell‐cycle resumption
           and progression
    • Authors: María T. L. Pino; Sandra V. Verstraeten
      Abstract: The effects of thallium [Tl(I) and Tl(III)] on the PC12 cell cycle were evaluated without (EGF−) or with (EGF+) media supplementation with epidermal growth factor (EGF). The following markers of cell‐cycle phases were analyzed: cyclin D1 (G1); E2F‐1, cyclin E and cytosolic p21 (G1→S transition); nuclear PCNA and cyclin A (S); and cyclin B1 (G2). The amount of cells in each phase and the activation of the signaling cascade triggered by EGF were also analyzed. Tl(I) and Tl(III) (5–100 μM) caused dissimilar effects on PC12 cell proliferation. In EGF− cells, Tl(I) increased the expression of G1→S transition markers and nuclear PCNA, without affecting cyclin A or cyclin B1. In addition to those, cyclin B1 was also increased in EGF+ cells. In EGF− cells, Tl(III) increased the expression of cyclin D1, all the G1→S and S phase markers and cyclin B1. In EGF+ cells, Tl(III) increased cyclin D1 expression and decreased all the markers of G1→S transition and the S phase. Even when these cations did not induce the activation of EGF receptor (EGFR) in EGF− cells, they promoted the phosphorylation of ERK1/2 and Akt. In the presence of EGF, the cations anticipated EGFR phosphorylation without affecting the kinetics of EGF‐dependent ERK1/2 and Akt phosphorylation. Altogether, results indicate that Tl(I) promoted cell proliferation in both EGF− and EGF+ cells. In contrast, Tl(III) promoted the proliferation of EGF− cells but delayed it in EGF+ cells, which may be related to the toxic effects of this cation in PC12 cells. Copyright © 2014 John Wiley & Sons, Ltd.
      PubDate: 2014-12-22T10:41:36.332836-05:
      DOI: 10.1002/jat.3096
       
  • All‐cause mortality increased by environmental cadmium exposure in
           the Japanese general population in cadmium non‐polluted areas
    • Authors: Yasushi Suwazono; Kazuhiro Nogawa, Yuko Morikawa, Muneko Nishijo, Etsuko Kobayashi, Teruhiko Kido, Hideaki Nakagawa, Koji Nogawa
      Abstract: The aim of the present study was to evaluate the effect of environmental cadmium (Cd) exposure indicated by urinary Cd on all‐cause mortality in the Japanese general population. A 19‐year cohort study was conducted in 1067 men and 1590 women aged 50 years or older who lived in three cadmium non‐polluted areas in Japan. The subjects were divided into four quartiles based on creatinine adjusted U‐Cd (µg g−1 cre). The hazard ratio (HR) and 95% confidence interval (CI) for continuous U‐Cd or the quartiles of U‐Cd were estimated for all‐cause mortality using a proportional hazards regression.The all‐cause mortality rates per 1000 person years were 31.2 and 15.1 in men and women, respectively. Continuous U‐Cd (+1 µg g−1 cre) was significantly related to the all‐cause mortality in men (HR 1.05, 95% CI: 1.02–1.09) and women (HR 1.04, 95% CI: 1.01–1.07). Furthermore in men, the third (1.96–3.22 µg g−1 cre) and fourth quartile (≥3.23 µg g−1 cre) of U‐Cd showed a significant, positive HR (third: HR 1.35, 95% CI: 1.03–1.77, fourth: HR 1.64, 95% CI: 1.26–2.14) for all‐cause mortality compared with the first quartile (
      PubDate: 2014-12-22T09:48:50.933751-05:
      DOI: 10.1002/jat.3077
       
  • In vitro neurotoxicity evaluation of piperazine designer drugs in
           differentiated human neuroblastoma SH‐SY5Y cells
    • 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.
       
  • Cellular uptake and toxicity effects of silver nanoparticles in mammalian
           kidney cells
    • Abstract: The rapid progress and early commercial acceptance of silver‐based nanomaterials is owed to their biocidal activity. Besides embracing the antimicrobial potential of silver nanoparticles (AgNPs), it is imperative to give special attention to the potential adverse health effects of nanoparticles owing to prolonged exposure. Here, we report a detailed study on the in vitro interactions of citrate‐coated AgNPs with porcine kidney (Pk15) cells. As uncertainty remains whether biological/cellular responses to AgNPs are solely as a result of the release of silver ions or whether the AgNPs themselves have toxic effects, we investigated the effects of Ag+ on Pk15 cells for comparison. Next, we investigated the cellular uptake of both AgNPs and Ag+ in Pk15 cells at various concentrations applied. The detected Ag contents in cells exposed to 50 mg l−1 AgNPs and 50 mg l−1 Ag+ were 209 and 25 µg of Ag per 106 cells, respectively. Transmission electron microscopy (TEM) images indicated that the Pk15 cells internalized AgNPs by endocytosis. Both forms of silver, nano and ionic, decreased the number of viable Pk15 cells after 24 h in a dose‐dependent manner. In spite of a significant uptake into the cells, AgNPs had only insignificant toxicity at concentrations lower than 25 mg l−1, whereas Ag+ exhibited a significant decrease in cell viability at one‐fifth of this concentration. The Comet assay suggested that a rather high concentration of AgNP (above 25 mg l−1) is able to induce genotoxicity in Pk15 cells. Further studies must seek deeper understanding of AgNP behavior in biological media and their interactions with cellular membranes. Copyright © 2014 John Wiley & Sons, Ltd.
       
  • Organ‐specific distribution of gold nanoparticles by their surface
           functionalization
    • Abstract: The behavior and fate of intravenously (i.v.) injected nanoparticles (NPs) can be controlled by several physicochemical factors including size, shape and surface charge. To evaluate the role of surface charge on distribution of NPs, we used neutral‐charged 15‐nm‐sized polyethylene glycol‐coated gold nanoparticles (AuNPPEG) as a core NP and carboxyl or amine groups were conjugated to AuNPPEG to generate negative (AuNPCOOH) or positive AuNP (AuNPNH2), respectively. Each type of AuNP was i.v. injected into mice (1 mg kg–1) and the concentration of Au was measured in different organs at 30 min, 4, 24 h, 7, 14 days, 1, 3 and 6 months post‐injection. The organ distribution also showed the higher deposition rate depending on their functional groups: AuNPPEG for mesenteric lymph node, kidney, brain and testis; AuNPCOOH for liver; AuNPNH2 for spleen, lung and heart. The blood circulation time and the major excretion route were different depending on their functional groups. In conclusion, functional groups conjugated on the surface of AuNPs produce differences in blood kinetics, organ distribution and elimination pattern which can be important information for directing NPs to specific organs or improving the kinetic properties. Copyright © 2014 John Wiley & Sons, Ltd.
       
  • Maternal exposure to 3,3’‐iminodipropionitrile targets
           late‐stage differentiation of hippocampal granule cell lineages to
           affect brain‐derived neurotrophic factor signaling and interneuron
           subpopulations in rat offspring
    • Abstract: 3,3’‐Iminodipropionitrile (IDPN) causes neurofilament (NF)‐filled swellings in the proximal segments of many large‐caliber myelinated axons. This study investigated the effect of maternal exposure to IDPN on hippocampal neurogenesis in rat offspring using pregnant rats supplemented with 0 (controls), 67 or 200 ppm IDPN in drinking water from gestational day 6 to day 21 after delivery. On postnatal day (PND) 21, female offspring subjected to analysis had decreased parvalbumin+, reelin+ and phospho‐TrkB+ interneurons in the dentate hilus at 200 ppm and increased granule cell populations expressing immediate‐early gene products, Arc or c‐Fos, at ≥  67 ppm. mRNA expression in the dentate gyrus examined at 200 ppm decreased with brain‐derived neurotrophic factor (Bdnf) and very low density lipoprotein receptor. Immunoreactivity for phosphorylated NF heavy polypeptide decreased in the molecular layer of the dentate gyrus and the stratum radiatum of the cornu ammonis (CA) 3, portions showing axonal projections from mossy cells and pyramidal neurons, at 200 ppm on PND 21, whereas immunoreactivity for synaptophysin was unchanged in the dentate gyrus. Observed changes all disappeared on PND 77. There were no fluctuations in the numbers of apoptotic cells, proliferating cells and subpopulations of granule cell lineage in the subgranular zone on PND 21 and PND 77. Thus, maternal IDPN exposure may reversibly affect late‐stage differentiation of granule cell lineages involving neuronal plasticity as evident by immediate‐early gene responses to cause BDNF downregulation resulting in a reduction in parvalbumin+ or reelin+ interneurons and suppression of axonal plasticity in the mossy cells and CA3 pyramidal neurons. Copyright © 2014 John Wiley & Sons, Ltd.
       
  • Induction of the estrogen‐responsive genes encoding choriogenin H
           and L in the liver of male medaka (Oryzias latipes) upon exposure to
           estrogen receptor subtype‐selective ligands
    • Abstract: Choriogenin (Chg) H and L are estrogen‐induced chorion precursors. We measured the induction of ChgH and ChgL mRNA in the livers of male medaka fish treated with Orthoester‐2k, a selective ligand for estrogen receptor (ER) α, and 2‐(4‐hydroxyphenyl)‐5‐hydroxy‐1,3‐benzoxazole (HPHB), a selective ligand of ERβ. Although both ChgH and ChgL mRNA were induced by treatment with Orthoester‐2k or HPHB separately, their combination induced much greater expression of each Chg. ChgH expression correlated more closely with Orthoester‐2k dosage when combined with a small fixed dose of HPHB (1 μm), whereas ChgL mRNA expression was more responsive to HPHB dose when combined with a fixed dose of Orthoester‐2k (2.8 nm). Moreover, upon long‐term treatment with Orthoester‐2k, ChgH mRNA and ERα mRNA expression showed similar patterns with peak expression between days 6 and 10. These results imply that ERβ primarily regulates ChgL mRNA expression and ERα action primarily regulates ChgH mRNA expression. Thus, it is necessary to develop screening methods for fish ER subtype‐specific ligands. Copyright © 2014 John Wiley & Sons, Ltd.
       
  • HepaRG culture in tethered spheroids as an in vitro
           three‐dimensional model for drug safety screening
    • Abstract: Conventional two‐dimensional (2D) monolayer cultures of HepaRG cells allow in vitro maintenance of many liver‐specific functions. However, cellular dedifferentiation and functional deterioration over an extended culture period in the conventional 2D HepaRG culture have hampered its applications in drug testing. To address this issue, we developed tethered spheroids of HepaRG cells on Arg–Gly–Asp (RGD) and galactose‐conjugated substratum with an optimized hybrid ratio as an in vitro three‐dimensional (3D) human hepatocyte model. The liver‐specific gene expression level and drug metabolizing enzyme activities in HepaRG‐tethered spheorids were markedly higher than those in 2D cultures throughout the culture period of 7 days. The inducibility of three major cytochrome P450 (CYP) enzymes, namely CYP1A2, CYP2B6 and CYP3A4, was improved in both mRNA and activity level in tethered spheroids. Drug‐induced cytotoxic responses to model hepatotoxins (acetaminophen, chlorpromazine and ketoconazole) in tethered spheroids were comparable to 2D cultures as well as other studies in the literature. Our results suggested that the HepaRG‐tethered spheroid would be an alternative in vitro model suitable for drug safety screening. Copyright © 2014 John Wiley & Sons, Ltd.
       
  • Combined exposure to lead, inorganic mercury and methylmercury shows
           deviation from additivity for cardiovascular toxicity in rats
    • Abstract: Environmental exposure to metal mixtures in the human population is common. Mixture risk assessments are often challenging because of a lack of suitable data on the relevant mixture. A growing number of studies show an association between lead or mercury exposure and cardiovascular effects. We investigated the cardiovascular effects of single metal exposure or co‐exposure to methylmercury [MeHg(I)], inorganic mercury [Hg(II)] and lead [Pb(II)]. Male Wistar rats received four different metal mixtures for 28 days through the drinking water. The ratios of the metals were based on reference and environmental exposure values. Blood and pulse pressure, cardiac output and electrical activity of the heart were selected as end‐points. While exposure to only MeHg(I) increased the systolic blood pressure and decreased cardiac output, the effects were reversed with combined exposures (antagonism). In contrast to these effects, combined exposures negatively affected the electrical activity of the heart (synergism). Thus, it appears that estimates of blood total Hg levels need to be paired with estimates of what species of mercury dominate exposure as well as whether lead co‐exposure is present to link total blood Hg levels to cardiovascular effects. Based on current human exposure data and our results, there may be an increased risk of cardiac events as a result of combined exposures to Hg(II), MeHg(I) and Pb(II). This increased risk needs to be clarified by analyzing lead and Hg exposure data in relation to cardiac electrical activity in epidemiological studies. Copyright © 2014 John Wiley & Sons, Ltd.
       
  • Ginsenoside Re protects methamphetamine‐induced mitochondrial
           burdens and proapoptosis via genetic inhibition of protein kinase C δ
           in human neuroblastoma dopaminergic SH‐SY5Y cell lines
    • Abstract: Recently, we have demonstrated that ginsenoside Re protects methamphetamine (MA)‐induced dopaminergic toxicity in mice via genetic inhibition of PKCδ and attenuation of mitochondrial stress. In addition, we have reported that induction of mitochondrial glutathione peroxidase (GPx) is also important for neuroprotection mediated by ginsenoside Re. To extend our knowledge, we examined the effects of ginsenoside Re against MA toxicity in vitro condition using SH‐SY5Y neuroblastoma cells. Treatment with ginsenoside Re resulted in significant attenuations against a decrease in the activity of GPx and an increase in the activity of superoxide dismutase (SOD) in the cytosolic and mitochondrial fraction. The changes in glutathione (GSH) paralleled those in GPx in the same experimental condition. Consistently, ginsenoside Re treatment exhibited significant protections against cytosolic and mitochondrial oxidative damage (i.e. lipid peroxidation and protein oxidation), mitochondrial translocation of PKCδ, mitochondrial dysfunction (mitochondrial transmembrane potential and intra‐mitochondrial Ca2+), apoptotic events [i.e., cytochrome c release from mitochondria, cleavage of caspase‐3 and poly(ADP‐ribose)polymerase‐1, nuclear condensation, terminal deoxynucleotidyl transferase‐mediated dUTP nick‐end labeling (TUNEL)‐positive apoptotic cells], and a reduction in the tyrosine hydroxylase (TH) expression and TH activity induced by MA in SH‐SY5Y neuroblastoma cells. These protective effects of ginsenoside Re were comparable to those of PKCδ antisense oligonucleotide (ASO). However, ginsenoside Re did not significantly provide additional protective effects mediated by genetic inhibition of PKCδ. Our results suggest that PKCδ is a specific target for ginsenoside Re‐mediated protective activity against MA toxicity in SH‐SY5Y neuroblastoma cells. Copyright © 2014 John Wiley & Sons, Ltd.
       
  • Culture conditions profoundly impact phenotype in BEAS‐2B, a human
           pulmonary epithelial model
    • Abstract: BEAS‐2B, an immortalized, human lung epithelial cell line, has been used to model pulmonary epithelial function for over 30 years. The BEAS‐2B phenotype can be modulated by culture conditions that include the presence or absence of fetal bovine serum (FBS). The popularity of BEAS‐2B as a model of arsenic toxicology, and the common use of BEAS‐2B cultured both with and without FBS, led us to investigate the impact of FBS on BEAS‐2B in the context of arsenic toxicology. Comparison of genome‐wide gene expression in BEAS‐2B cultured with or without FBS revealed altered expression in several biological pathways, including those related to carcinogenesis and energy metabolism. Real‐time measurements of oxygen consumption and glycolysis in BEAS‐2B demonstrated that FBS culture conditions were associated with a 1.4‐fold increase in total glycolytic capacity, a 1.9‐fold increase in basal respiration, a 2.0‐fold increase in oxygen consumed for ATP production and a 2.8‐fold increase in maximal respiration, compared with BEAS‐2B cultured without FBS. Comparisons of the transcriptome changes in BEAS‐2B resulting from FBS exposure to the transcriptome changes resulting from exposure to 1 μM sodium arsenite revealed that mRNA levels of 43% of the arsenite‐modulated genes were also modulated by FBS. Cytotoxicity studies revealed that BEAS‐2B cells exposed to 5% FBS for 8 weeks were almost 5 times more sensitive to arsenite cytotoxicity than non‐FBS‐exposed BEAS‐2B cells. Phenotype changes induced in BEAS‐2B by FBS suggest that culture conditions should be carefully considered when using BEAS‐2B as an experimental model of arsenic toxicity. Copyright © 2014 John Wiley & Sons, Ltd.
       
  • Establishment of a mouse model for amiodarone‐induced liver injury
           and analyses of its hepatotoxic mechanism
    • 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.
       
  • 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.
       
  • In vitro study of biocompatibility of a graphene composite with gold
           nanoparticles and hydroxyapatite on human osteoblasts
    • 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.
       
  • Bisphenol A inhibits duodenal movement ex vivo of rat through nitric
           oxide‐mediated soluble guanylyl cyclase and α‐adrenergic
           signaling pathways
    • 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.
       
  • 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.
       
 
 
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