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  Subjects -> ENVIRONMENTAL STUDIES (Total: 752 journals)
    - ENVIRONMENTAL STUDIES (679 journals)
    - POLLUTION (22 journals)
    - TOXICOLOGY AND ENVIRONMENTAL SAFETY (41 journals)
    - WASTE MANAGEMENT (10 journals)

ENVIRONMENTAL STUDIES (679 journals)            First | 1 2 3 4     

Showing 601 - 378 of 378 Journals sorted alphabetically
Scientific Journal of Environmental Sciences     Open Access   (Followers: 1)
Sepsis     Hybrid Journal  
Smart Grid and Renewable Energy     Open Access   (Followers: 8)
Social and Environmental Accountability Journal     Hybrid Journal   (Followers: 2)
Soil and Sediment Contamination: An International Journal     Hybrid Journal   (Followers: 3)
Soil and Tillage Research     Hybrid Journal   (Followers: 6)
SourceOCDE Environnement et developpement durable     Full-text available via subscription   (Followers: 1)
SourceOECD Environment & Sustainable Development     Full-text available via subscription  
South Pacific Journal of Natural and Applied Sciences     Hybrid Journal  
Southern Forests : a Journal of Forest Science     Hybrid Journal   (Followers: 6)
Stochastic Environmental Research and Risk Assessment     Hybrid Journal   (Followers: 4)
Strategic Behavior and the Environment     Full-text available via subscription  
Strategic Planning for Energy and the Environment     Hybrid Journal   (Followers: 4)
Studies in Conservation     Hybrid Journal   (Followers: 11)
Studies in Environmental Science     Full-text available via subscription   (Followers: 6)
Sustainability     Open Access   (Followers: 18)
Sustainability in Environment     Open Access  
Sustainability of Water Quality and Ecology     Hybrid Journal   (Followers: 2)
Sustainable Cities and Society     Hybrid Journal   (Followers: 25)
Sustainable Development     Hybrid Journal   (Followers: 16)
Sustainable Development Law & Policy     Open Access   (Followers: 6)
Sustainable Development Strategy and Practise     Open Access  
Sustainable Environment Research     Open Access  
Sustainable Technologies, Systems & Policies     Open Access   (Followers: 9)
TECHNE - Journal of Technology for Architecture and Environment     Open Access   (Followers: 5)
Tecnogestión     Open Access  
Territorio della Ricerca su Insediamenti e Ambiente. Rivista internazionale di cultura urbanistica     Open Access  
The Historic Environment : Policy & Practice     Hybrid Journal   (Followers: 4)
The International Journal on Media Management     Hybrid Journal   (Followers: 4)
Theoretical Ecology     Hybrid Journal   (Followers: 9)
Theoretical Ecology Series     Full-text available via subscription   (Followers: 1)
Toxicologic Pathology     Hybrid Journal   (Followers: 16)
Toxicological & Environmental Chemistry     Hybrid Journal   (Followers: 4)
Toxicological Sciences     Hybrid Journal   (Followers: 11)
Toxicology     Hybrid Journal   (Followers: 16)
Toxicology and Applied Pharmacology     Hybrid Journal   (Followers: 17)
Toxicology and Industrial Health     Hybrid Journal   (Followers: 7)
Toxicology in Vitro     Hybrid Journal   (Followers: 12)
Toxicology Letters     Hybrid Journal   (Followers: 12)
Toxicology Mechanisms and Methods     Hybrid Journal   (Followers: 10)
Toxicon     Hybrid Journal   (Followers: 3)
Toxin Reviews     Hybrid Journal   (Followers: 1)
Trace Metals and other Contaminants in the Environment     Full-text available via subscription   (Followers: 2)
Trace Metals in the Environment     Full-text available via subscription   (Followers: 2)
Transportation Research Part D: Transport and Environment     Hybrid Journal   (Followers: 27)
Transylvanian Review of Systematical and Ecological Research     Open Access  
Trends in Ecology & Evolution     Full-text available via subscription   (Followers: 167)
Trends in Environmental Analytical Chemistry     Hybrid Journal   (Followers: 2)
Trends in Pharmacological Sciences     Full-text available via subscription   (Followers: 25)
Turkish Journal of Engineering and Environmental Sciences     Open Access   (Followers: 1)
UCLA Journal of Environmental Law and Policy     Open Access   (Followers: 5)
UD y la Geomática     Open Access  
Universidad y Ciencia     Open Access   (Followers: 1)
Urban Studies     Hybrid Journal   (Followers: 48)
Veredas do Direito : Direito Ambiental e Desenvolvimento Sustentável     Open Access  
VertigO - la revue électronique en sciences de l’environnement     Open Access   (Followers: 3)
Villanova Environmental Law Journal     Open Access  
Waste Management & Research     Hybrid Journal   (Followers: 10)
Water Environment Research     Full-text available via subscription   (Followers: 37)
Water International     Hybrid Journal   (Followers: 12)
Water, Air, & Soil Pollution     Hybrid Journal   (Followers: 22)
Water, Air, & Soil Pollution : Focus     Hybrid Journal   (Followers: 9)
Waterlines     Full-text available via subscription   (Followers: 2)
Weather and Forecasting     Full-text available via subscription   (Followers: 15)
Weather, Climate, and Society     Full-text available via subscription   (Followers: 9)
Web Ecology     Open Access   (Followers: 6)
Wetlands     Hybrid Journal   (Followers: 24)
Wilderness & Environmental Medicine     Hybrid Journal   (Followers: 3)
Wildlife Australia     Full-text available via subscription   (Followers: 2)
Wiley Interdisciplinary Reviews - Climate Change     Hybrid Journal   (Followers: 17)
Wiley Interdisciplinary Reviews : Energy and Environment     Hybrid Journal   (Followers: 4)
William & Mary Environmental Law and Policy Review     Open Access   (Followers: 2)
World Environment     Open Access   (Followers: 1)
World Journal of Entrepreneurship, Management and Sustainable Development     Hybrid Journal   (Followers: 4)
World Journal of Environmental Engineering     Open Access   (Followers: 2)
World Journal of Environmental Research     Open Access   (Followers: 1)
Worldviews: Global Religions, Culture, and Ecology     Hybrid Journal   (Followers: 8)
Zoology and Ecology     Hybrid Journal   (Followers: 4)
气候与环境研究     Full-text available via subscription   (Followers: 1)

  First | 1 2 3 4     

Journal Cover Journal of Applied Toxicology
  [SJR: 0.996]   [H-I: 61]   [15 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  [1609 journals]
  • Natural remedies for non‐steroidal anti‐inflammatory
           drug‐induced toxicity
    • Authors: Jerine Peter Simon; Sabina Evan Prince
      Abstract: The liver is an important organ of the body, which has a vital role in metabolic functions. The non‐steroidal anti‐inflammatory drug (NSAID), diclofenac causes hepato‐renal toxicity and gastric ulcers. NSAIDs are noted to be an agent for the toxicity of body organs. This review has elaborated various scientific perspectives of the toxicity caused by diclofenac and its mechanistic action in affecting the vital organ. This review suggests natural products are better remedies than current clinical drugs against the toxicity caused by NSAIDs. Natural products are known for their minimal side effects, low cost and availability. On the other hand, synthetic drugs pose the danger of adverse effects if used frequently or over a long period. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-09-22T02:20:46.590665-05:
      DOI: 10.1002/jat.3391
       
  • Toxic effects of 4‐methylthio‐3‐butenyl isothiocyanate (Raphasatin)
           in the rat urinary bladder without genotoxicity
    • Abstract: We recently reported that 4‐methylthio‐3‐butenyl isothiocyanate (MTBITC) exerts chemopreventive effects on the rat esophageal carcinogenesis model at a low dose of 80 ppm in a diet. In contrast, some isothiocyanates (ITCs) have been reported to cause toxic effects, promotion activity, and/or carcinogenic potential in the urinary bladder of rats. In the present study, we investigated whether MTBITC had toxic effects in the urinary bladder similar to other ITCs, such as phenethyl ITC (PEITC). First, to examine the early toxicity of MTBITC, rats were fed a diet supplemented with 100, 300 or 1000 ppm MTBITC for 14 days. Treatment with 1000 ppm MTBITC caused increased organ weights and histopathological changes in the urinary bladder, producing lesions similar to those of 1000 ppm PEITC. In contrast, rats treated with 100 or 300 ppm MTBITC showed no signs of toxicity. Additionally, we performed in vivo genotoxicity studies to clarify whether MTBITC may exhibit a carcinogenic potential through a genotoxic mechanism in rats. Rats were treated with MTBITC for 3 days at doses of 10, 30 or 90 mg kg−1 body weight by gavage, and comet assays in the urinary bladder and micronucleus assays in the bone marrow were performed. No genotoxic changes were observed after treatment with MTBITC at all doses. Overall, these results suggested that the effects of MTBITC in the rat urinary bladder are less than those of PEITC, but that MTBITC could have toxic effects through a nongenotoxic mechanism in the urinary bladder of rats at high doses. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-09-15T23:31:54.945759-05:
      DOI: 10.1002/jat.3384
       
  • Oxidative stress and cytotoxic effects of silver ion in mouse lung
           macrophages J774.1 cells
    • Authors: Ilseob Shim; Kyunghee Choi, Seishiro Hirano
      Abstract: Silver is commonly used as a disinfectant, and chronic exposure to silver may cause argyria, resulting in a gray–blue discoloration of human skin. However, the mechanism for cellular toxicity of silver has not been well explained. We studied the mode of cell death, the ratio of glutathione disulfide/glutathione, induction of metallothionein and activation of mitogen‐activated protein kinases in J774.1 cells together with activation of antioxidant responsive element and nuclear factor‐κB in CHO cells following exposure to silver ion (Ag+) to investigate the mechanism by which Ag+ causes lethal effects. Ag+ increased phosphorylation levels of extracellular signal‐regulated, c‐Jun N‐terminal and p38 mitogen‐activated protein kinases and remarkably increased the ratio of glutathione disulfide/glutathione in both a time‐ and concentration‐dependent manner. Luciferase reporter gene assays revealed that antioxidant responsive element and nuclear factor‐κB were activated following exposure to Ag+. In addition, exposure to Ag+ increased the mRNA and protein levels of metallothionein. We investigated whether or not Ag+ killed J774.1 cells by inducing apoptosis. Ag+ increased the activity of caspase‐3/7 which was abrogated by caspase 3 and pan‐caspase inhibitors. However, these inhibitors did not ameliorate the cytotoxic effects of Ag+, suggesting that Ag+ causes oxidative stress, which leads to necrotic rather than apoptotic cell death in J774.1 cells by decreasing functional sulfhydryl groups including glutathione in the cells. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-09-14T04:55:49.311991-05:
      DOI: 10.1002/jat.3382
       
  • Biologic activity of cyclic and caged phosphates: a review
    • Abstract: The recognition in the early 1960s by Morifusa Eto that tri‐o‐cresyl phosphate (TOCP) is hydroxylated by the cytochrome P450 system to an intermediate that spontaneously cyclizes to a neurotoxic phosphate (saligenin phosphate ester) ignited the interest in this group of compounds. Only the ortho isomer can cyclize and clinically cause Organo Phosphate Induced Delayed Neurotoxicity (OPIDN); the meta and para isomers of tri‐cresyl phosphate are not neuropathic because they are unable to form stable cyclic saligenin phosphate esters. This review identifies the diverse biological effects associated with various cyclic and caged phosphates and phosphonates and their possible use. Cyclic compounds that inhibit acetylcholine esterase (AChE), such as salithion, can be employed as pesticides. Others are neurotoxic, most probably because of inhibition of neuropathy target esterase (NTE). Cyclic phosphates that inhibit lipases, the cyclipostins, possibly represent promising therapeutic avenues for the treatment of type 2 diabetes mellitus and/or microbial infections; those compounds inhibiting β‐lactamase may prevent bacterial resistance against β‐lactam antibiotics. Naturally occurring cyclic phosphates, such as cyclic AMP, cyclic phosphatidic acid and the ryanodine receptor modulator cyclic adenosine diphosphate ribose, play an important physiological role in signal transduction. Moreover, some cyclic phosphates are GABA‐antagonists, while others are an essential component of Molybdenum‐containing enzymes. Some cyclic phosphates (cyclophosphamide, ifosfamide) are clinically used in tumor therapy, while the coupling of therapeutic agents with other cyclic phosphates (HepDirect® Technology) allows drugs to be targeted to specific organs. Possible clinical applications of these compounds are considered. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-09-09T11:17:34.349526-05:
      DOI: 10.1002/jat.3369
       
  • Correlation between antibodies to bisphenol A, its target enzyme protein
           disulfide isomerase and antibodies to neuron‐specific antigens
    • Authors: Datis Kharrazian; Aristo Vojdani
      Abstract: Evidence continues to increase linking autoimmunity and other complex diseases to the chemicals commonly found in our environment. Bisphenol A (BPA) is a synthetic monomer used widely in many forms, from food containers to toys, medical products and many others. The potential for BPA to participate as a triggering agent for autoimmune diseases is likely due to its known immunological influences. The goal of this research was to determine if immune reactivity to BPA has any correlation with neurological antibodies. BPA binds to a target enzyme called protein disulfide isomerase (PDI). Myelin basic protein (MBP) and myelin oligodendrocyte glycoprotein (MOG) are neuronal antigens that are target sites for neuroinflammation and neuroautoimmunity. We determined the co‐occurrence of anti‐MBP and anti‐MOG antibodies with antibodies made against BPA bound to human serum albumin in 100 healthy human subjects. Correlation between BPA to PDI, BPA to MOG, BPA to MBP, PDI to MBP and PDI to MOG were all highly statistically significant (P 
      PubDate: 2016-09-09T11:17:13.249387-05:
      DOI: 10.1002/jat.3383
       
  • Comparative genotoxicity of silver nanoparticles in human liver HepG2 and
           lung epithelial A549 cells
    • Authors: J. Wang; B. Che, L. W. Zhang, G. Dong, Q. Luo, L. Xin
      Abstract: With the rapid expanding of human exposure to silver nanoparticles (AgNPs), genotoxicity screening of nanosilver is necessary to ensure consumer safety. Here, we assessed one key DNA damage responsive pathway activated by GADD45a gene after 24 h of AgNPs exposure in stable luciferase reporter cell systems based on two widely used in vitro cell models, human liver HepG2 and lung epithelial A549 cells. The comet assay and micronucleus test were also conducted to confirm the genetic damage induced by AgNPs. Our results showed that AgNPs produced a strong dose‐dependent increase in transcriptional activation of GADD45a promoter indicated by luciferase activity accompanying by the significant decreases in cell viability. Surprisingly, in HepG2‐luciferase cells, the relative luciferase activity was greater than 4.5× the control level after being treated with 200 μg ml–1 AgNPs. These results were generally in line with the positive and dose‐dependent responses in cytotoxicity, DNA strand breaks indicated by Olive tail moment, tail DNA (%) and tail length, and chromosome damage indicated by induction of micronuclei, nucleoplasmic bridges, and nuclear buds. Additionally, compared with the A549‐luciferase cells, the HepG2‐luciferase cells seemed to be more susceptible to AgNPs as higher levels of genotoxicity were induced. We concluded that our GADD45a promoter‐driven luciferase reporter gene cell system, together with the comet assay and micronucleus test, can be used as valuable tools for rapid screening of genotoxic potential of nanosilver. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-09-07T06:45:50.883692-05:
      DOI: 10.1002/jat.3385
       
  • Exposure to cyclic volatile methylsiloxanes (cVMS) causes
           anchorage‐independent growth and reduction of BRCA1 in non‐transformed
           human breast epithelial cells
    • Authors: Abdullah Farasani; Philippa D. Darbre
      Abstract: Dermal absorption of components of personal care products (PCPs) may contribute to breast cancer development. Cyclic volatile methylsiloxanes (cVMS) are used widely in the formulation of PCPs, and their presence has been recently detected in human blood. The objectives of this study were to investigate any genotoxic effects after short‐ (1 week) or longer‐term (30 weeks) exposure to hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4) or decamethylcyclopentasiloxane (D5) in MCF‐10 A and MCF‐10F immortalized non‐transformed human breast epithelial cells. Genotoxic effects were assessed by an ability of cells to grow in suspension culture, from DNA damage measured by comet assays, and from a reduction in levels of DNA repair proteins measured by RT‐PCR and western immunoblotting. Dose‐dependent anchorage‐independent growth in methocel culture was observed after exposure to D3 (10−13 M–10−5 M) and D4/D5 (10−9 M–10−5 M). DNA damage was measured by the comet assay after 1‐h exposure to D3 (10−6 M–10−5 M) and D4 (10−5 M). BRCA1 mRNA and BRCA1 protein levels were reduced after 30‐week exposure to 10−5 M D4 and D5 in both cell lines. Reduced levels of mRNAs for other DNA repair proteins (BRCA2, ATM, ATR, CHK1 and CHK2) were also observed after exposure to 10−5 M D5 in both cell lines, and some reductions after exposure to D3 and D4. If cVMS can not only enable anchorage‐independent growth of non‐transformed breast epithelial cells and damage DNA, but also compromise DNA repair systems, then there is the potential for them to impact on breast carcinogenesis. Further risk assessment now requires information concerning the extent to which cVMS may be present in human breast tissues. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-09-07T06:30:25.910126-05:
      DOI: 10.1002/jat.3378
       
  • The role of surface chemistry in the cytotoxicity profile of graphene
    • Authors: Waqar Majeed; Shawn Bourdo, Dayton M. Petibone, Viney Saini, Kieng Bao Vang, Zeid A. Nima, Karrer M. Alghazali, Emilie Darrigues, Anindya Ghosh, Fumiya Watanabe, Daniel Casciano, Syed F. Ali, Alexandru S. Biris
      Abstract: Graphene and its derivative, because of their unique physical, electrical and chemical properties, are an important class of nanomaterials being proposed as foundational materials in nanomedicine as well as for a variety of industrial applications. A major limitation for graphene, when used in biomedical applications, is its poor solubility due to its rather hydrophobic nature. Therefore, chemical functionalities are commonly introduced to alter both its surface chemistry and biochemical activity. Here, we show that surface chemistry plays a major role in the toxicological profile of the graphene structures. To demonstrate this, we chemically increased the oxidation level of the pristine graphene and compared the corresponding toxicological effects along with those for the graphene oxide. X‐ray photoelectron spectroscopy revealed that pristine graphene had the lowest amount of surface oxygen, while graphene oxide had the highest at 2.5% and 31%, respectively. Low and high oxygen functionalized graphene samples were found to have 6.6% and 24% surface oxygen, respectively. Our results showed a dose‐dependent trend in the cytotoxicity profile, where pristine graphene was the most cytotoxic, with decreasing toxicity observed with increasing oxygen content. Increased surface oxygen also played a role in nanomaterial dispersion in water or cell culture medium over longer periods. It is likely that higher dispersity might result in graphene entering into cells as individual flakes ~1 nm thick rather than as more cytotoxic aggregates. In conclusion, changes in graphene's surface chemistry resulted in altered solubility and toxicity, suggesting that a generalized toxicity profile would be rather misleading. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-09-04T22:00:26.495518-05:
      DOI: 10.1002/jat.3379
       
  • Effects of methyl mercury exposure on pancreatic beta cell development and
           function
    • Authors: Lauren Schumacher; Louise C. Abbott
      Abstract: Methyl mercury is an environmental contaminant of worldwide concern. Since the discovery of methyl mercury exposure due to eating contaminated fish as the underlying cause of the Minamata disaster, the scientific community has known about the sensitivity of the developing central nervous system to mercury toxicity. Warnings are given to pregnant women and young children to limit consumption of foods containing methyl mercury to protect the embryonic, fetal and postnatally developing central nervous system. However, evidence also suggests that exposure to methyl mercury or various forms of inorganic mercury may also affect development and function of other organs. Numerous reports indicate a worldwide increase in diabetes, particularly type 2 diabetes. Quite recently, methyl mercury has been shown to have adverse effects on pancreatic beta (β) cell development and function, resulting in insulin resistance and hyperglycemia and may even lead to the development of diabetes. This review discusses possible mechanisms by which methyl mercury exposure may adversely affect pancreatic β cell development and function, and the role that methyl mercury exposure may have in the reported worldwide increase in diabetes, particularly type 2 diabetes. While additional information is needed regarding associations between mercury exposure and specific mechanisms of the pathogenesis of diabetes in the human population, methyl mercury's adverse effects on the body's natural sources of antioxidants suggest that one possible therapeutic strategy could involve supplementation with antioxidants. Thus, it is important that additional investigation be undertaken into the role of methyl mercury exposure and reduced pancreatic β cell function. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-09-04T22:00:17.284753-05:
      DOI: 10.1002/jat.3381
       
  • Pharmacokinetics of 14C‐ortho‐phenylphenol following
           intravenous administration in pigs
    • Authors: Emma Nixon; James D. Brooks, Patricia A. Routh, Jason T. Chittenden, Ronald E. Baynes
      Abstract: Workers in the USA are exposed to industrial formulations, which may be toxic. These formulations often contain preservatives or biocides such as ortho‐phenylphenol (OPP). There are limited data describing OPP following intravenous administration to assess truly the clearance of this chemical in humans and other species. In vivo experiments were conducted in pigs to determine related pharmacokinetic parameters. 14C‐OPP was administered as an intravenous bolus dose. Blood, feces, urine and tissue samples were collected for analysis by liquid scintillation. Data were analyzed using non‐compartmental and compartmental pharmacokinetic model approaches. These data fitted a three‐compartment model and showed that the half‐life of 14C‐OPP following the intravenous bolus in pigs was 46.26 ± 10.01 h. The kidneys play a crucial role in clearance of 14C‐OPP with a large percentage of the dose being found in the urine (70.3 ± 6.9% dose). Comparisons with other species suggest that 14C‐OPP clearance in pigs (2.48 ml h–1 kg–1) is less than that in humans (18.87 ml h–1 kg–1) and rats (35.51 ml h–1 kg–1). Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-09-04T22:00:09.282996-05:
      DOI: 10.1002/jat.3380
       
  • Differences in the mechanisms of action of BDE‐47 and its metabolites on
           OVCAR‐3 and MCF‐7 cell apoptosis
    • Abstract: Data concerning possible carcinogenic action of polybrominated diphenyl ethers (PBDEs) in hormone‐dependent tissues are limited. Our earlier studies showed that 2,2′,4,4′‐tetrabromodiphenyl ether (BDE‐47) stimulated OVCAR‐3 and MCF‐7 cell proliferation, while its hydroxylated metabolites (5‐OH‐BDE‐47 and 6‐OH‐BDE‐47) increased estrogen receptors protein expression and extracellular signal‐regulated kinase 1/2 and protein kinase Cα phosphorylation in these cell lines. In addition to cell proliferative disorder, a failure in the regulation of apoptosis can also lead to the formation and development of tumors. Therefore, in the present study, we investigated the effect of BDE‐47 and its metabolites (2.5–50 ng ml–1) on the expression of apoptosis regulatory genes and proteins, caspase‐8 and ‐9 activity and DNA fragmentation induced by extracellular signal‐regulated kinase inhibitor (PD098059) and protein kinase Cα inhibitor (Gӧ 6976) in ovarian (OVCAR‐3) and breast (MCF‐7) cancer cells. In OVCAR‐3 cells, BDE‐47 upregulated expression of most of the investigated genes and increased protein expression of tumor necrosis factor (TNF)‐α, TNF receptor 1, caspase‐6, Bcl‐xl and caspase‐8 activity. Whereas in MCF‐7 cells, BDE‐47 resulted in the downregulation of most of the investigated genes, and decreased caspase‐8 and ‐9 activity. In both OVCAR‐3 and MCF‐7 cells, the expression of most of the investigated genes were downregulated by metabolites. Exposure of OVCAR‐3 cells to 5‐OH‐BDE‐47 corresponded with a decrease in the protein expression of caspase‐6, caspase‐9 and Bcl‐xl and treatment with 6‐OH‐BDE‐47 decreased Bcl‐xl and TNF receptor 1 expression in OVCAR‐3 cells and caspase‐9 expression in MCF‐7 cells. Hydroxylated metabolites of BDE‐47 have strong inhibitory effects on apoptosis in ovarian and breast tumor cells and thus should be considered potential carcinogens in hormone‐dependent cancers. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-09-02T10:05:24.975284-05:
      DOI: 10.1002/jat.3375
       
  • Methylparaben stimulates tumor initiating cells in ER+ breast cancer
           models
    • Abstract: A body of epidemiological evidence implicates exposure to endocrine disrupting chemicals (EDCs) with increased susceptibility to breast cancer. To evaluate the physiological effects of a suspected EDC in vivo, we exposed MCF‐7 breast cancer cells and a patient‐derived xenograft (PDX, estrogen receptor positive) to physiological levels of methylparaben (mePB), which is commonly used in personal care products as a preservative. mePB pellets (4.4 μg per day) led to increased tumor size of MCF‐7 xenografts and ER+ PDX tumors. mePB has been thought to be a xenoestrogen; however, in vitro exposure of 10 nM mePB failed to increase MCF‐7 cell proliferation or induction of canonical estrogen‐responsive genes (pS2 and progesterone receptor), in contrast to 17β‐estradiol (E2) treatment. MCF‐7 and PDX‐derived mammospheres exhibited increased size and up‐regulation of canonical stem cell markers ALDH1, NANOG, OCT4 and SOX2 when exposed to mePB; these effects were not observed for MDA‐MB‐231 (ER−) mammospheres. As tumor‐initiating cells (TICs) are also believed to be responsible for chemoresistance, mammospheres were treated with either tamoxifen or the pure anti‐estrogen fulvestrant in the presence of mePB. Blocking the estrogenic response was not sufficient to block NANOG expression in mammospheres, pointing to a non‐classic estrogen response or an ER‐independent mechanism of mePB promotion of mammosphere activity. Overall, these results suggest that mePB increases breast cancer tumor proliferation through enhanced TIC activity, in part via regulation of NANOG, and that mePB may play a direct role in chemoresistance by modulating stem cell activity. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-09-01T02:21:04.824239-05:
      DOI: 10.1002/jat.3374
       
  • Observations on conducting whole‐cell patch clamping of the hERG cardiac
           K+ channel in pure human serum
    • Authors: Jiesheng Kang; Yongyi Luo, Michelle Searles, David Rampe
      Abstract: Inhibition of the human ether‐a‐go‐go‐related gene (hERG) K+ channel by drugs leads to QT prolongation on the electrocardiogram and can result in serious cardiac arrhythmia. For this reason, screening of drugs on hERG is mandatory during the drug development process. Patch clamp electrophysiology in a defined physiological saline solution (PSS) represents the standard method for assaying drug effects on the channel. To make the assay more translatable to clinical studies, we have conducted whole‐cell patch clamping of hERG using pure human serum as the extracellular medium. Pure human serum had little effect on the hERG channel waveform or the current–voltage relationship when compared to PSS. hERG current recordings were highly stable in serum at room temperature, but prolonged recordings at the physiological temperature required prior heat inactivation of the serum. Compared to PSS, the IC50 values, conducted at room temperature, of the classic hERG blocking drugs cisapride, moxifloxacin, and terfenadine were shifted to the right by an extent predicted by their known plasma protein binding, but we did not detect any differences in IC50s between male and female serum. Total plasma levels of these drugs associated with clinical QT prolongation corresponded to small (
      PubDate: 2016-08-24T01:35:38.572982-05:
      DOI: 10.1002/jat.3377
       
  • RNA‐sequencing analysis reveals the hepatotoxic mechanism of
           perfluoroalkyl alternatives, HFPO2 and HFPO4, following exposure in mice
    • Authors: Jianshe Wang; Xiaoyang Wang, Nan Sheng, Xiujuan Zhou, Ruina Cui, Hongxia Zhang, Jiayin Dai
      Abstract: The toxicological impact of traditional perfluoroalkyl chemicals has led to the elimination and restriction of these substances. However, many novel perfluoroalkyl alternatives remain unregulated and little is known about their potential effects on environmental and human health. Daily administration of two alternative perfluoroalkyl substances, HFPO2 and HFPO4 (1 mg kg−1 body weight), for 28 days resulted in hepatomegaly and hepatic histopathological injury in mice, particularly in the HFPO4 group. We generated and compared high‐throughput RNA‐sequencing data from hepatic tissues in control and treatment group mice to clarify the mechanism of HFPO2 and HFPO4 hepatotoxicity. We identified 146 (101 upregulated, 45 downregulated) and 1295 (716 upregulated, 579 downregulated) hepatic transcripts that exhibited statistically significant changes (fold change ≥2 or ≤0.5, false discovery rate 
      PubDate: 2016-08-24T01:25:56.405956-05:
      DOI: 10.1002/jat.3376
       
  • Comparative ovarian microarray analysis of juvenile hormone‐responsive
           genes in water flea Daphnia magna: potential targets for toxicity
    • Authors: Kenji Toyota; Timothy D. Williams, Tomomi Sato, Norihisa Tatarazako, Taisen Iguchi
      Abstract: The freshwater zooplankton Daphnia magna has been extensively employed in chemical toxicity tests such as OECD Test Guidelines 202 and 211. Previously, it has been demonstrated that the treatment of juvenile hormones (JHs) or their analogues to female daphnids can induce male offspring production. Based on this finding, a rapid screening method for detection of chemicals with JH‐activity was recently developed using adult D. magna. This screening system determines whether a chemical has JH‐activity by investigating the male offspring inducibility. Although this is an efficient high‐throughput short‐term screening system, much remains to be discovered about JH‐responsive pathways in the ovary, and whether different JH‐activators act via the same mechanism. JH‐responsive genes in the ovary including developing oocytes are still largely undescribed. Here, we conducted comparative microarray analyses using ovaries from Daphnia magna treated with fenoxycarb (Fx; artificial JH agonist) or methyl farnesoate (MF; a putative innate JH in daphnids) to elucidate responses to JH agonists in the ovary, including developing oocytes, at a JH‐sensitive period for male sex determination. We demonstrate that induction of hemoglobin genes is a well‐conserved response to JH even in the ovary, and a potential adverse effect of JH agonist is suppression of vitellogenin gene expression, that might cause reduction of offspring number. This is the first report demonstrating different transcriptomics profiles from MF and an artificial JH agonist in D. magna ovary, improving understanding the tissue‐specific mode‐of‐action of JH. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-08-24T01:25:51.702113-05:
      DOI: 10.1002/jat.3368
       
  • Salinity‐dependent toxicity of water‐dispersible, single‐walled
           carbon nanotubes to Japanese medaka embryos
    • Authors: Chisato Kataoka; Kousuke Nakahara, Kaori Shimizu, Shinsuke Kowase, Seiji Nagasaka, Shinsuke Ifuku, Shosaku Kashiwada
      Abstract: To investigate the effects of salinity on the behavior and toxicity of functionalized single‐walled carbon nanotubes (SWCNTs), which are chemical modified nanotube to increase dispersibility, medaka embryos were exposed to non‐functionalized single‐walled carbon nanotubes (N‐SWCNTs), water‐dispersible, cationic, plastic‐polymer‐coated, single‐walled carbon nanotubes (W‐SWCNTs), or hydrophobic polyethylene glycol‐functionalized, single‐walled carbon nanotubes (PEG‐SWCNTs) at different salinities, from freshwater to seawater. As reference nanomaterials, we tested dispersible chitin nanofiber (CNF), chitosan‐chitin nanofiber (CCNF) and chitin nanocrystal (CNC, i.e. shortened CNF). Under freshwater conditions, with exposure to 10 mg l−1 W‐SWCNTs, the yolk sacks of 57.8% of embryos shrank, and the remaining embryos had a reduced heart rate, eye diameter and hatching rate. Larvae had severe defects of the spinal cord, membranous fin and tail formation. These toxic effects increased with increasing salinity. Survival rates declined with increasing salinity and reached 0.0% in seawater. In scanning electron microscope images, W‐SWCNTs, CNF, CCNF and CNC were adsorbed densely over the egg chorion surface; however, because of chitin's biologically harmless properties, only W‐SWCNTs had toxic effects on the medaka eggs. No toxicity was observed from N‐SWCNT and PEG‐SWCNT exposure. We demonstrated that water dispersibility, surface chemistry, biomedical properties and salinity were important factors in assessing the aquatic toxicity of nanomaterials. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-08-18T04:50:32.43129-05:0
      DOI: 10.1002/jat.3373
       
  • Sex‐specific characterization and evaluation of the Alzheimer's disease
           genetic risk factor sorl1 in zebrafish during aging and in the adult brain
           following a 100 ppb embryonic lead exposure
    • Authors: Jinyoung Lee; Samuel M. Peterson, Jennifer L. Freeman
      Abstract: Developmental lead (Pb) exposure is suggested in laboratory studies to be a trigger for neurodegenerative diseases such as Alzheimer's disease (AD). Sortilin‐related receptor, L (DLR class) A repeats‐containing (SORL1) is a recently identified AD genetic risk factor. SORL1 has limited characterization in vertebrate models in comparison to other AD genetic risk factors. To characterize SORL1 further, protein sequence homology between humans, mice and zebrafish was analyzed and showed conservation of functional repeats and domain orientation. Next, spatial expression of sorl1 in zebrafish larvae was completed and diffuse expression in neural tissue that was not restricted to the brain was observed. Influences of sex and age on quantitative expression of sorl1 in the brain of adult zebrafish were then assessed. Sex‐specific alteration of sorl1 expression transpired during the aging process in females. The zebrafish was then utilized to investigate the impacts of a 100 ppb embryonic Pb exposure on sorl1 expression and other known AD genetic risk factors. Sex‐specific quantitative gene expression analysis was completed with adult zebrafish brain to compare those developmentally exposed to Pb or a control treatment, but no significant difference in sorl1 expression or other AD genetic risk factors was observed. Overall, this study provided characterization of sorl1 with changes in brain expression during aging being female‐specific. This finding is in agreement with females being more prone to the onset of AD, but analysis of additional AD genetic risk factors is needed to facilitate our understanding of the impact of a 100 ppb embryonic Pb exposure. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-08-18T04:45:32.56419-05:0
      DOI: 10.1002/jat.3372
       
  • Effects of soap–water wash on human epidermal penetration
    • PubDate: 2016-08-05T06:31:46.866476-05:
      DOI: 10.1002/jat.3370
       
  • Combining web‐based tools for transparent evaluation of data for risk
           assessment: developmental effects of bisphenol A on the mammary gland as a
           case study
    • Abstract: Different tools have been developed that facilitate systematic and transparent evaluation and handling of toxicity data in the risk assessment process. The present paper sets out to explore the combined use of two web‐based tools for study evaluation and identification of reliable data relevant to health risk assessment. For this purpose, a case study was performed using in vivo toxicity studies investigating low‐dose effects of bisphenol A on mammary gland development. The reliability of the mammary gland studies was evaluated using the Science in Risk Assessment and Policy (SciRAP) criteria for toxicity studies. The Health Assessment Workspace Collaborative (HAWC) was used for characterizing and visualizing the mammary gland data in terms of type of effects investigated and reported, and the distribution of these effects within the dose interval. It was then investigated whether there was any relationship between study reliability and the type of effects reported and/or their distribution in the dose interval. The combination of the SciRAP and HAWC tools allowed for transparent evaluation and visualization of the studies investigating developmental effects of BPA on the mammary gland. The use of these tools showed that there were no apparent differences in the type of effects and their distribution in the dose interval between the five studies assessed as most reliable and the whole data set. Combining the SciRAP and HAWC tools was found to be a useful approach for evaluating in vivo toxicity studies and identifying reliable and sensitive information relevant to regulatory risk assessment of chemicals. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-08-04T02:55:33.536584-05:
      DOI: 10.1002/jat.3363
       
  • A modified multiparametric assay using HepaRG cells for predicting the
           degree of drug‐induced liver injury risk
    • Authors: Takafumi Tomida; Hayao Okamura, Tsuyoshi Yokoi, Yoshihiro Konno
      Abstract: The approach for predicting the degree of drug‐induced liver injury (DILI) risk was investigated quantitatively in a modified multiparametric assay using HepaRG cells. Thirty‐eight drugs were classified by DILI risk into five categories based on drug labels approved by the Food and Drug Administration (FDA) as follows: withdrawn (WDN), boxed warning (BW), warnings and precautions (WP), adverse reactions (AR), and no match (NM). Also, WP was classified into two categories: high and low concern. Differentiated HepaRG cells were treated with drugs for 24 h. The maximum concentration was set at 100‐fold the therapeutic maximum plasma concentration (Cmax). After treatment with drugs, the cell viability, glutathione content, caspase 3/7 activity, lactate dehydrogenase leakage and albumin secretion were measured. As modified cut‐off values of each parameter, the TC50 (toxic concentration that decreased the response by 50%) and EC200 (effective concentration giving a response equal to 200% of controls) were calculated. In addition, the toxicity score (total sum score of the cytotoxic level of each parameter) was calculated. This modified multiparametric assay showed an 87% sensitivity and 87% specificity for predicting the DILI risk. The toxicity score showed a good predictive performance for WDN, BW and WP (high concern) categories [cut‐off: score ≥ 1; area under a receiver operating characteristic curve (ROC‐AUC): 0.88], and for WDN and BW categories (cut‐off: score ≥ 3; ROC‐AUC: 0.88). This study newly indicated that the degree of DILI risk might be predictable quantitatively by assessing the toxicity score in the modified multiparametric assay using HepaRG cells. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-08-02T06:16:51.114998-05:
      DOI: 10.1002/jat.3371
       
  • Cytotoxicity and proliferative capacity impairment induced on human brain
           cell cultures after short‐ and long‐term exposure to magnetite
           nanoparticles
    • Abstract: Since magnetic iron oxide nanoparticles (IONP) as magnetite (Fe3O4NPs) have potential applications in life sciences, industrial fields and biomedical care, the risks for occupational, general population and patients rises correspondingly. Excessive IONP accumulation in central nervous system (CNS) cells can lead to a disruption of normal iron metabolism/homeostasis, which is a characteristic hallmark resembling that of several neurodegenerative disorders. Fe3O4NPs‐ versus Fe3O4 bulk‐induced toxic effects have been assessed in two human CNS cells namely astrocytes (D384) and neurons (SH‐SY5Y) after short‐term exposure (4–24‐48 h) to 1–100 μg ml−1, and long‐term exposure to lower concentrations. Short‐term Fe3O4NPs induced significant concentration‐ and time‐dependent alterations of mitochondrial function in D384 (25–75% cell viability decrease): effects started at 25 μg ml−1 after 4 h, and 1 μg ml−1 after 48 h. SH‐SY5Y were less susceptible: cytotoxicity occurred after 48  h only with 35–45% mortality (10–100 μg ml−1). Accordingly, a more marked intracellular iron accumulation was observed in astrocytes than neurons. Membrane integrity was unaltered in both CNS cell types. Lowering Fe3O4NP concentrations (0.05–10 μg ml−1) and prolonging the exposure time (up to 10 days), D384 toxicity was again observed (colony number decrease at ≥0.05 μg ml−1, morphology alterations and colony size reduction at ≥0.5 μg ml−1). Effects on SH‐SY5Y appeared at the highest concentration only. Fe3O4 bulk was always remarkably toxic toward both cells. In summary, human cultured astrocytes were susceptible to both Fe3O4NP and bulk forms following short‐term and extended exposure to low concentrations, while neurons were more resistant to NPs. Cellular iron overload may trigger adverse responses by releasing iron ions (particularly in astrocytes) thus compromising the normal functions of CNS. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-08-02T06:06:33.450912-05:
      DOI: 10.1002/jat.3367
       
  • Multivariate models for prediction of human skin sensitization hazard
    • Authors: Judy Strickland; Qingda Zang, Michael Paris, David M. Lehmann, David Allen, Neepa Choksi, Joanna Matheson, Abigail Jacobs, Warren Casey, Nicole Kleinstreuer
      Abstract: One of the Interagency Coordinating Committee on the Validation of Alternative Method's (ICCVAM) top priorities is the development and evaluation of non‐animal approaches to identify potential skin sensitizers. The complexity of biological events necessary to produce skin sensitization suggests that no single alternative method will replace the currently accepted animal tests. ICCVAM is evaluating an integrated approach to testing and assessment based on the adverse outcome pathway for skin sensitization that uses machine learning approaches to predict human skin sensitization hazard. We combined data from three in chemico or in vitro assays – the direct peptide reactivity assay (DPRA), human cell line activation test (h‐CLAT) and KeratinoSens™ assay – six physicochemical properties and an in silico read‐across prediction of skin sensitization hazard into 12 variable groups. The variable groups were evaluated using two machine learning approaches, logistic regression and support vector machine, to predict human skin sensitization hazard. Models were trained on 72 substances and tested on an external set of 24 substances. The six models (three logistic regression and three support vector machine) with the highest accuracy (92%) used: (1) DPRA, h‐CLAT and read‐across; (2) DPRA, h‐CLAT, read‐across and KeratinoSens; or (3) DPRA, h‐CLAT, read‐across, KeratinoSens and log P. The models performed better at predicting human skin sensitization hazard than the murine local lymph node assay (accuracy 88%), any of the alternative methods alone (accuracy 63–79%) or test batteries combining data from the individual methods (accuracy 75%). These results suggest that computational methods are promising tools to identify effectively the potential human skin sensitizers without animal testing. Published 2016. This article has been contributed to by US Government employees and their work is in the public domain in the USA.
      PubDate: 2016-08-02T06:03:58.640092-05:
      DOI: 10.1002/jat.3366
       
  • Development of an in vivo anti‐androgenic activity detection assay using
           fenitrothion in Japanese medaka (Oryzias latipes)
    • Authors: Yoshifumi Horie; Haruna Watanabe, Hitomi Takanobu, Ayano Yagi, Takahiro Yamagishi, Taisen Iguchi, Norihisa Tatarazako
      Abstract: The effects of endocrine disruptors, including anti‐androgenic chemicals, on aquatic environments have received increased attention in recent years. Currently, the method used to screen chemicals for anti‐androgenic activity is called the androgenized female stickleback screen, and it was established by the Organization of Economic Cooperation and Development in 2011 using the three‐spined stickleback. However, screening chemicals for anti‐androgenic activity has yet to be established using Japanese medaka. Thus, the purpose of this study was to establish a screening method for anti‐androgenic activity utilizing the number of papillary processes in Japanese medaka (Oryzias latipes) as an indicator of the chemical's anti‐androgenic activity. Thus, at 35 days post‐fertilization, medaka were exposed to fenitrothion, an anti‐androgenic compound, for 28 days. In the control group, the formation of papillary processes was observed in XY medaka, but not in XX medaka. However, after fenitrothion exposure, the number of papillary processes was significantly decreased in a dose‐dependent manner in XY medaka; in the 300 μg l−1 concentration group, four of 11 XY medaka showed no papillary processes even if there were no significant effects on total length and wet body weight compared with the control group. Our results indicate that the number of papillary processes in Japanese medaka can be used as an indicator of anti‐androgenic activity and that this model may prove useful as a chemical screening method. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-07-27T07:20:27.803937-05:
      DOI: 10.1002/jat.3365
       
  • Gender and geographical variability in the exposure pattern and metabolism
           of deoxynivalenol in humans: a review
    • Abstract: Deoxynivalenol (DON, also known as vomitoxin) is a common mycotoxin found worldwide, especially in contaminated food. DON is toxic to a variety of cells and tissues in humans. Three kinds of conjugated products (DON‐3‐glucuronide, DON‐15‐glucuronide and DON‐7‐glucuronide) can be found as major metabolites in human urine. Females and males show different patterns of exposure levels, and human exposure to DON also shows some geographical differences because of different DON levels in cereal‐based foods, food intake habits and UDP‐glucuronosyltransferase expression. Specifically, the C12, 13‐deepoxy metabolite was found predominantly in French adults but was rarely detected in UK adults. However, a cohort of Spanish individuals demonstrated even lower DON levels than the levels in the UK populations, whereas a very high DON exposure level was detected in South Africa and Linxian, China. Recent publications have further indicated that DON could be detected in the urine of pregnant women from different countries, which suggests that there is a potential risk to both mothers and foetuses. Additionally, phytochemicals have been shown to be less toxic to cells and laboratory animals in research studies and may also be used as food additives for reducing the toxic effects of DON. In this review, we provide global information on DON metabolism, human exposure and gender differences in humans. Also, control strategies for this mycotoxin are discussed. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-07-26T03:56:47.324771-05:
      DOI: 10.1002/jat.3359
       
  • Effect of 4‐week inhalation exposure to 1‐bromopropane on
           blood pressure in rats
    • Authors: Fen Huang; Sahoko Ichihara, Yuki Yamada, Shameema Banu, Gaku Ichihara
      Abstract: The pathophysiology of hypertension is complex and multifactorial, and includes exposure to various chemical substances. Several recent studies have documented the reproductive and neurological toxicities of 1‐bromopropane (1‐BP). Given that 1‐BP increased reactive oxygen species in the brain of rats, we hypothesized that 1‐BP also has cardiovascular toxicity through increased oxidative stress. To test this hypothesis, male F344 and Wistar Nagoya rats (n = 7–8 per group per test) were exposed to 0 or 1000 ppm of 1‐BP via inhalation for 4 weeks (8 h per day, 7 days per week). The exposure to 1‐BP increased systolic blood pressure. This effect was associated with a significant decrease in the reduced/oxidized glutathione ratio. A significant increase in nitrotyrosine levels, activation of the NADPH oxidase pathway, which was evidenced by upregulation of gp91phox, a NADPH oxidase subunit, and significant decreases in the expressions of antioxidant molecules such as Cu/Zn‐ and Mn‐superoxide dismutase catalase, and nuclear factor erythroid 2‐related factor 2, were observed in the aortas of Wistar Nagoya rats exposed to 1‐BP. Our results indicate that subacute (4‐week) inhalation exposure to 1‐BP increases blood pressure and suggest that this cardiovascular toxic effect is due, at least in part, to increased oxidative stress mediated through activation of the NADPH oxidase pathway. Further study is needed to assess whether NADPH oxidase activation causes the increase in blood pressure in the rats exposed to 1‐BP. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-07-25T00:30:39.872069-05:
      DOI: 10.1002/jat.3364
       
  • The C. elegans model in toxicity testing
    • Authors: Piper Reid Hunt
      Abstract: Caenorhabditis elegans is a small nematode that can be maintained at low cost and handled using standard in vitro techniques. Unlike toxicity testing using cell cultures, C. elegans toxicity assays provide data from a whole animal with intact and metabolically active digestive, reproductive, endocrine, sensory and neuromuscular systems. Toxicity ranking screens in C. elegans have repeatedly been shown to be as predictive of rat LD50 ranking as mouse LD50 ranking. Additionally, many instances of conservation of mode of toxic action have been noted between C. elegans and mammals. These consistent correlations make the case for inclusion of C. elegans assays in early safety testing and as one component in tiered or integrated toxicity testing strategies, but do not indicate that nematodes alone can replace data from mammals for hazard evaluation. As with cell cultures, good C. elegans culture practice (GCeCP) is essential for reliable results. This article reviews C. elegans use in various toxicity assays, the C. elegans model's strengths and limitations for use in predictive toxicology, and GCeCP. Published 2016. This article is a U.S. Government work and is in the public domain in the USA. Journal of Applied Toxicology published by John Wiley & Sons Ltd.
      PubDate: 2016-07-22T01:45:37.492847-05:
      DOI: 10.1002/jat.3357
       
  • Pulmonary persistence of graphene nanoplatelets may disturb physiological
           and immunological homeostasis
    • Abstract: Accumulated evidence suggests that chronic pulmonary accumulation of harmful particles cause adverse pulmonary and systemic health effects. In our previous study, most of the graphene nanoplatelet (GNP) remained in the lung until 28 days after a single instillation. In this study, we sought to evaluate the local and systemic health effect after a long pulmonary persistence of GNP. As expected, GNP remained in the lung on day 90 after a single intratracheal instillation (1.25, 2.5 and 5 mg kg−1). In the lung exposed at the highest dose, the total number of cells and the percentage of lymphocytes significantly increased in the BAL fluid with an increase in both the number of GNP‐engulfed macrophages and the percentage of apoptotic cells. A Th1‐shifted immune response, the elevated chemokine secretion and the enhanced expression of cytoskeletal‐related genes were observed. Additionally, the expression of natriuretic‐related genes was noteworthy altered in the lungs. Moreover, the number of white blood cells (WBC) and the percentage of macrophages and neutrophils clearly increased in the blood of mice exposed to a 5‐mg kg−1 dose, whereas total protein, BUN and potassium levels significantly decreased. In conclusion, we suggest that the long persistence of GNP in the lung may cause adverse health effects by disturbing immunological‐ and physiological‐homeostasis of our body. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-07-21T05:50:40.280098-05:
      DOI: 10.1002/jat.3361
       
  • Hepatocytes cocultured with Sertoli cells in bioreactor favors Sertoli
           barrier tightness in rat
    • Authors: P. Zeller; A. Legendre, S. Jacques, M. J. Fleury, F. Gilard, G. Tcherkez, E. Leclerc
      Abstract: The lack of a reliable in vitro system to assess reprotoxicity is an emerging problem in the context of European law for Registration, Evaluation, Authorization and Restriction of Chemicals (REACH, 2007), as it requires a reduction in animal utilization for testing. Furthermore, in vitro reprotoxicological tests would be more relevant and greatly improved by integrating both hepatic metabolism and the blood–testis barrier. Here, we took advantage of an integrated insert in a dynamic microfluidic platform (IIDMP) to co‐cultivate hepatocytes in biochip and Sertoli cells in the bicameral chamber. This microfluidic tool has been previously demonstrated to be helpful in cell function and/or quality improvement. We demonstrate that permeability of the Sertoli barrier is reduced by dynamic coculture in our system. Exometabolomics analysis reveals that interactions between hepatocytes and Sertoli cells may have been mediated by the polyamines increase and/or mid‐chain fatty acid decrease in the circulating medium. These metabolic changes may be involved in permeability reduction by contributing to modifying junction protein quantity and localization. The present study gives an example of IIDMP as an in vitro partitioning/transport model for cell culture and toxicological testing. Further, based on both our previous results using an intestinal–hepatic cell coculture and the present study, IIDMP seems to be well‐suited for (i) assessing the dose–response effect of chemicals within the rodent or human male reproductive tract, and (ii) improving the quality of reprotoxicological assays by including hepatic metabolism. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-07-21T05:45:34.727774-05:
      DOI: 10.1002/jat.3360
       
  • In vitro toxicology studies of extracellular vesicles
    • Authors: Sayantan Maji; Irene K. Yan, Mansi Parasramka, Swathi Mohankumar, Akiko Matsuda, Tushar Patel
      Abstract: Extracellular vesicles (EVs) are membrane‐bound vesicles released from cells into the extracellular environment. There is emerging interest in the use of EVs as potential therapeutic interventions. We sought to evaluate the safety of EVs that may be therapeutically used by performing in vitro toxicological assessments. EVs were obtained from mesenchymal stem cells (MSC‐EV) or from bovine milk (BM‐EV) by differential ultracentrifugation, and quantitated using nanoparticle tracking analysis. Genotoxic effects, hematological effects, immunological effects and endotoxin production were evaluated at two dose levels. Neither MSC‐EVs nor BM‐EVs elicited detectable genotoxic effects using either the alkaline comet assay or micronucleus assay. Hemolysis was observed with BM‐EVs but not with MSC‐EVs. MSC‐EVs did not have any significant effect on either spontaneous or collagen‐induced platelet aggregation. In contrast, BM‐EVs were noted to increase collagen‐induced platelet aggregation, even though no spontaneous increase in platelet aggregation was noted. Both types of EVs induced leukocyte proliferation, which was greater with BM‐EV. Neither MSC‐EVs nor BM‐EVs induced HL‐60 phagocytosis, although BM‐EVs decreased zymosan‐induced phagocytosis. Furthermore, neither MSC‐EVs nor BM‐EVs induced nitric oxide production. Unlike MSC‐EVs, BM‐EVs tested positive for endotoxin and induced complement activation. There are significant differences in toxicological profiles between MSC‐EVs and BM‐EVs that may reflect variations in techniques for EV isolation, EV content or cross‐species differences. The safety of MSC‐EV supports their use for disease therapeutics, whereas detailed safety and toxicological assessment will be necessary before the use of BM‐EVs. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-07-20T05:20:51.296356-05:
      DOI: 10.1002/jat.3362
       
  • Molecular docking reveals the potential of phthalate esters to inhibit the
           enzymes of the glucocorticoid biosynthesis pathway
    • Authors: Shahzad Ahmad; Mohemmed Faraz Khan, Suhel Parvez, Mohammad Akhtar, Sheikh Raisuddin
      Abstract: Glucocorticoids (GCs) are well known to exert broad‐based effects on metabolism, behavior and immunity. Their impaired synthesis and production lead to adverse health effects. Some environmental toxicants, including phthalate esters (PAEs), are associated with endocrine disruption. These endocrine‐disrupting chemicals (EDCs) also cause adrenal toxicity and alteration of GC biosynthesis and their functions. Using in silico tools of Schrodinger Maestro 9.4, we performed a molecular docking study of 32 ligands including PAEs of a known endocrine‐disrupting potential with the selected enzymes of the GC biosynthesis pathway (GBP) such as CYP11A1, CYP11B2, CYP19A1, CYP17A1, CYP21A2 and 3α/20β‐HSD. Binding affinities of the PAEs were compared with known inhibitors of these enzymes. Amongst PAEs, diphenyl benzene‐1, 2 – dicarboxylate (DPhP) showed the lowest docking score of −8.95616 kcal mol−1 against CYP21A1. Besides, benzyl butyl benzene‐1,2‐dicarboxylate (BBzP), bis(7‐methylnonyl) benzene‐1,2 dicarboxylate (DIDP) and bis(2‐ethylhexyl) benzene‐1,2‐dicarboxylate (DEHP) also showed comparable molecular interaction with enzymes of GBP. DPhP showed a significant molecular interaction with different enzymes of GBP such as CYP21A1, CYP11A1 and CYP11B2. These interactions mainly included H‐bonding, hydrophobic, polar and van dar Waals' interactions. Interestingly, this in silico study revealed that certain PAEs have more inhibitory potential against enzymes of GBP than their respective known inhibitors. Such studies become more relevant in the risk assessment of exposure to mixtures of phthalate eaters. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-07-18T01:01:17.086181-05:
      DOI: 10.1002/jat.3355
       
  • Identification of microRNA biomarker candidates in urine and plasma from
           rats with kidney or liver damage
    • Authors: Francis S. Wolenski; Pooja Shah, Tomoya Sano, Tadahiro Shinozawa, Hugues Bernard, Matt J. Gallacher, Shylah D. Wyllie, Georgianna Varrone, Lisa A. Cicia, Mary E. Carsillo, Craig D. Fisher, Sean E. Ottinger, Erik Koenig, Patrick J. Kirby
      Abstract: MicroRNAs (miRNA) are short single‐stranded RNA sequences that have a role in the post‐transcriptional regulation of genes. The identification of tissue specific or enriched miRNAs has great potential as novel safety biomarkers. One longstanding goal is to associate the increase of miRNA in biofluids (e.g., plasma and urine) with tissue‐specific damage. Next‐generation sequencing (miR‐seq) was used to analyze changes in miRNA profiles of tissue, plasma and urine samples of rats treated with either a nephrotoxicant (cisplatin) or one of two hepatotoxicants (acetaminophen [APAP] or carbon tetrachloride [CCL4]). Analyses with traditional serum chemistry and histopathology confirmed that toxicant‐induced organ damage was specific. In animals treated with cisplatin, levels of five miRNAs were significantly altered in the kidney, 14 in plasma and six in urine. In APAP‐treated animals, five miRNAs were altered in the liver, 74 in plasma and six in urine; for CCL4 the changes were five, 20 and 6, respectively. Cisplatin treatment caused an elevation of miR‐378a in the urine, confirming the findings of other similar studies. There were 17 in common miRNAs elevated in the plasma after treatment with either APAP or CCL4. Four of these (miR‐122, −802, −31a and −365) are known to be enriched in the livers of rats. Interestingly, the increase of serum miR‐802 in both hepatotoxicant treatments was comparable to that of the well‐known liver damage marker miR‐122. Taken together, comparative analysis of urine and plasma miRNAs demonstrated their utility as biomarkers of organ injury. Copyright © 2016 The
      Authors . Journal of Applied Toxicology published by John Wiley & Sons Ltd.
      PubDate: 2016-07-11T03:20:51.930644-05:
      DOI: 10.1002/jat.3358
       
  • Anthophyllite asbestos: state of the science review
    • Authors: Shannon H. Gaffney; Matthew Grespin, Lindsey Garnick, Derek A. Drechsel, Rebecca Hazan, Dennis J. Paustenbach, Brooke D. Simmons
      Abstract: Anthophyllite is an amphibole form of asbestos historically used in only a limited number of products. No published resource currently exists that offers a complete overview of anthophyllite toxicity or of its effects on exposed human populations. We performed a review focusing on how anthophyllite toxicity was understood over time by conducting a comprehensive search of publicly available documents that discussed the use, mining, properties, toxicity, exposure and potential health effects of anthophyllite. Over 200 documents were identified; 114 contained relevant and useful information which we present chronologically in this assessment. Our analysis confirms that anthophyllite toxicity has not been well studied compared to other asbestos types. We found that toxicology studies in animals from the 1970s onward have indicated that, at sufficient doses, anthophyllite can cause asbestosis, lung cancer and mesothelioma. Studies of Finnish anthophyllite miners, conducted in the 1970s, found an increased incidence of asbestosis and lung cancer, but not mesothelioma. Not until the mid‐1990s was an epidemiological link with mesothelioma in humans observed. Its presence in talc has been of recent significance in relation to potential asbestos exposure through the use of talc‐containing products. Characterizing the health risks of anthophyllite is difficult, and distinguishing between its asbestiform and non‐asbestiform mineral form is essential from both a toxicological and regulatory perspective. Anthophyllite toxicity has generally been assumed to be similar to other amphiboles from a regulatory standpoint, but some notable exceptions exist. In order to reach a more clear understanding of anthophyllite toxicity, significant additional study is needed. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-07-11T03:05:57.857656-05:
      DOI: 10.1002/jat.3356
       
  • Is skin penetration a determining factor in skin sensitization potential
           and potency' Refuting the notion of a LogKow threshold for skin
           sensitization
    • Authors: Jeremy M. Fitzpatrick; David W. Roberts, Grace Patlewicz
      Abstract: It is widely accepted that substances that cannot penetrate through the skin will not be sensitizers. LogKow and molecular weight (MW) have been used to set thresholds for sensitization potential. Highly hydrophilic substances e.g. LogKow ≤ 1 are expected not to penetrate effectively to induce sensitization. To investigate whether LogKow >1 is a true requirement for sensitization, a large dataset of substances that had been evaluated for their skin sensitization potential under Registration, Evaluation, Authorisation and restriction of CHemicals (REACH), together with available measured LogKow values was compiled using the OECD eChemPortal. The incidence of sensitizers relative to non‐sensitizers above and below a LogKow of 1 was explored. Reaction chemistry principles were used to explain the sensitization observed for the subset of substances with a LogKow ≤0. 1482 substances were identified with skin sensitization data and measured LogKow values. 525 substances had a measured LogKow ≤ 1, 100 of those were sensitizers. There was no significant difference in the incidence of sensitizers above and below a LogKow of 1. Reaction chemistry principles that had been established for lower MW and more hydrophobic substances were found to be still valid in rationalizing the skin sensitizers with a LogKow ≤ 0. The LogKow threshold arises from the widespread misconception that the ability to efficiently penetrate the stratum corneum is a key determinant of sensitization potential and potency. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-06-29T20:40:33.379277-05:
      DOI: 10.1002/jat.3354
       
  • Toxicity of single‐wall carbon nanotubes functionalized with
           polyethylene glycol in zebrafish (Danio rerio) embryos
    • Abstract: Single‐wall carbon nanotubes functionalized with polyethylene glycol (SWCNT‐PEG) are promising materials for biomedical applications such as diagnostic devices and controlled drug‐release systems. However, several questions about their toxicological profile remain unanswered. Thus, the aim of this study was to investigate the action of SWCNT‐PEG in Danio rerio zebrafish embryos at the molecular, physiological and morphological levels. The SWCNT used in this study were synthesized by the high‐pressure carbon monoxide process, purified and then functionalized with distearoyl phosphatidylethanolamine block copolymer‐PEG (molecular weight 2 kDa). The characterization process was carried out with low‐resolution transmission electron microscopy, thermogravimetric analysis and Raman spectroscopy. Individual zebrafish embryos were exposed to the SWCNT‐PEG. Toxic effects occurred only at the highest concentration tested (1 ppm) and included high mortality rates, delayed hatching and decreased total larval length. For all the concentrations tested, the alkaline comet assay revealed no genotoxicity, and Raman spectroscopy measurements on the histological slices revealed no intracellular nanotubes. The results shown here demonstrate that SWCNT‐PEG has low toxicity in zebrafish embryos, but more studies are needed to understand what mechanisms are involved. However, the presence of residual metals is possibly among the primary mechanisms responsible for the toxic effects observed, because the purification process was not able to remove all metal contamination, as demonstrated by the thermogravimetric analysis. More attention must be given to the toxicity of these nanomaterials before they are used in biomedical applications. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-06-20T03:40:51.371492-05:
      DOI: 10.1002/jat.3346
       
  • Cytotoxic effects of psychotropic benzofuran derivatives,
           N‐methyl‐5‐(2‐aminopropyl)benzofuran and its N‐demethylated
           derivative, on isolated rat hepatocytes
    • Authors: Yoshio Nakagawa; Toshinari Suzuki, Yukie Tada, Akiko Inomata
      Abstract: The novel psychoactive compounds derived from amphetamine have been illegally abused as recreational drugs, some of which are known to be hepatotoxic in humans and experimental animals. The cytotoxic effects and mechanisms of 5‐(2‐aminopropyl)benzofuran (5‐APB) and N‐methyl‐5‐(2‐aminopropyl)benzofuran (5‐MAPB), both of which are benzofuran analogues of amphetamine, and 3,4‐methylenedioxy‐N‐methamphetamine (MDMA) were studied in freshly isolated rat hepatocytes. 5‐MAPB caused not only concentration‐dependent (0–4.0 mm) and time‐dependent (0–3 h) cell death accompanied by the depletion of cellular ATP and reduced glutathione and protein thiol levels, but also accumulation of oxidized glutathione. Of the other analogues examined at a concentration of 4 mm, 5‐MAPB/5‐APB‐induced cytotoxicity with the production of reactive oxygen species and loss of mitochondrial membrane potential was greater than that induced by MDMA. In isolated rat liver mitochondria, the benzofurans resulted in a greater increase in the rate of state 4 oxygen consumption than did MDMA, with a decrease in the rate of state 3 oxygen consumption. Furthermore, the benzofurans caused more of a rapid mitochondrial swelling dependent on the mitochondrial permeability transition than MDMA. 5‐MAPB at a weakly toxic level (1 mm) was metabolized slowly: levels of 5‐MAPB and 5‐APB were approximately 0.9 mm and 50 μm, respectively, after 3 h incubation. Taken collectively, these results indicate that mitochondria are target organelles for the benzofuran analogues and MDMA, which elicit cytotoxicity through mitochondrial failure, and the onset of cytotoxicity may depend on the initial and/or residual concentrations of 5‐MAPB rather than on those of its metabolite 5‐APB. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-06-13T01:10:49.273901-05:
      DOI: 10.1002/jat.3351
       
  • Detection of exposure effects of mixtures of heavy polycyclic aromatic
           hydrocarbons in zebrafish embryos
    • Authors: Alejandro Barranco; Laura Escudero, Jon Sanz Landaluze, Sandra Rainieri
      Abstract: In this study we evaluated the exposure effects of mixtures of five polycyclic aromatic hydrocarbons (PAHs); namely, benzo[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene and chrysene on zebrafish embryos. Supplementation of the exposure media with 0.45% dimethyl sulfoxide and 50 ppm of Tween 20 could guarantee the solubilization and stabilization of the PAHs up to 24 h without affecting the embryos development. The exposure effects were tested by detecting the differential expression of a number of genes related to the aryl hydrocarbon receptor gene battery. Effects were detectable already after 6 h of exposure. After 24 h of exposure, all PAHs, except for benzo[a]anthracene, acted as potent inducers of the gene cyp1a1. Benzo[k]fluoranthene was the major inducer; the effect caused by the mixture at the lower concentration tested (1 ng ml−1) was dominated by its presence. However, in the mixture at the highest concentration tested (10 ng ml−1) it caused less induction and was not dominant. No significant bioaccumulation values were detected on embryos exposed to the PAHs tested in this study; however, the results obtained, indicated that PAHs undergo a very rapid metabolization inside the embryos, and that those biotransformation products yield changes on the expression of genes involved in the aryl hydrocarbon receptor pathway. Future work should focus on identification of the PAH metabolization products and on the effect of these metabolites on toxicity. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-06-10T01:25:31.717541-05:
      DOI: 10.1002/jat.3353
       
  • What determines skin sensitization potency: Myths, maybes and realities.
           The 500 molecular weight cut‐off: An updated analysis
    • Authors: Jeremy M. Fitzpatrick; David W. Roberts, Grace Patlewicz
      Abstract: It is widely accepted that substances must have a molecular weight (MW)  500, five were sensitizers. This provided good evidence to refute such a MW 500 threshold. While Roberts et al. (2012) made a convincing case that the MW > 500 cut‐off was not a true requirement for sensitization, the number of counter examples identified were too few to draw any statistical conclusions. This updated analysis systematically interrogated a large repository of sensitization information collected under the EU REACH regulation. A data set of 2904 substances that had been tested for skin sensitization, using guinea pigs and/or mice were collected. The data set contained 197 substances with a MW > 500; 33 of these were skin sensitizers. Metal containing complexes, reaction products and mixtures were excluded from further consideration. The final set of 14 sensitizers substantiated the original findings. The study also assessed whether the same reaction chemistry principles established for low MW sensitizers applied to chemicals with a MW > 500. The existing reaction chemistry considerations were found appropriate to rationalize the sensitization behaviour of the 14 sensitizers with a MW > 500. The existence of the MW 500 threshold, based on the widespread misconception that the ability to penetrate efficiently the stratum corneum is a key determinant of skin sensitization potential and potency, was refuted. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-06-10T01:15:33.619414-05:
      DOI: 10.1002/jat.3348
       
  • Comparative oral dose toxicokinetics of sodium selenite and
           selenomethionine
    • Authors: T. Zane Davis; Asheesh K. Tiwary, Bryan L. Stegelmeier, James A. Pfister, Kip E. Panter, Jeffery O. Hall
      Abstract: Selenium (Se) poisoning by different forms of Se occurs in the United States. However, the toxicokinetics of different selenocompounds after oral ingestion is not well documented. In this study the toxicokinetics of Se absorption, distribution and elimination were determined in serum and whole blood of lambs that were orally dosed with increasing doses of Se as sodium selenite (inorganic Se) or selenomethionine (SeMet, organic Se). Thirty‐two lambs were randomly assigned to eight treatment groups, with four animals per group. Se was administered at 1, 2 or 3 mg kg−1 body weight, as either sodium selenite or SeMet with proper control groups. Blood and serum were collected at predetermined time points for 7 days post‐dosing. Resulting Se concentrations in both serum and whole blood from SeMet treatment groups were significantly greater than those given equimolar doses of Se as sodium selenite. Se concentrations in serum and whole blood of lambs dosed with SeMet peaked at significantly greater concentrations when compared with lambs dosed with equimolar doses of sodium selenite. Based on the serum and whole blood kinetics, the rate of Se absorption was greater for SeMet than for sodium selenite although rates of absorption for both Se forms decreased with increasing dose. The rates of Se elimination increased with dose. These results demonstrate that SeMet has a greater absorption rate and a similar retention time resulting in a greater area under the curve and thus bioavailability than sodium selenite, which must be considered in both overdose and nutritional exposures. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.
      PubDate: 2016-06-10T01:05:25.404061-05:
      DOI: 10.1002/jat.3350
       
  • Does industry take the susceptible subpopulation of asthmatic individuals
           into consideration when setting derived no‐effect levels'
    • Abstract: Asthma, a chronic respiratory disease, can be aggravated by exposure to certain chemical irritants. The objectives were first to investigate the extent to which experimental observations on asthmatic subjects are taken into consideration in connection with the registration process under the EU REACH regulation, and second, to determine whether asthmatics are provided adequate protection by the derived no‐effect levels (DNELs) for acute inhalation exposure. We identified substances for which experimental data on the pulmonary functions of asthmatics exposed to chemicals under controlled conditions are available. The effect concentrations were then compared with DNELs and other guideline and limit values. As of April 2015, only 2.6% of 269 classified irritants had available experimental data on asthmatics. Fourteen of the 22 identified substances with available data were fully registered under REACH and we retrieved 114 reliable studies related to these. Sixty‐three of these studies, involving nine of the 14 substances, were cited by the REACH registrants. However, only 17 of the 114 studies, involving four substances, were regarded as key studies. Furthermore, many of the DNELs for acute inhalation were higher than estimated effect levels for asthmatics, i.e., lowest observed adverse effect concentrations or no‐observed adverse effect concentrations, indicating low or no safety margin. We conclude that REACH registrants tend to disregard findings on asthmatics when deriving these DNELs. In addition, we found examples of DNELs, particularly among those derived for workers, which likely do not provide adequate protection for asthmatics. Copyright © 2016 The
      Authors Journal of Applied Toxicology Published by John Wiley & Sons Ltd.
      PubDate: 2016-06-09T20:45:26.640453-05:
      DOI: 10.1002/jat.3352
       
  • Development of the Larval Amphibian Growth and Development Assay: Effects
           of benzophenone‐2 exposure in Xenopus laevis from embryo to juvenile
    • Authors: Jonathan T. Haselman; Maki Sakurai, Naoko Watanabe, Yasushi Goto, Yuta Onishi, Yuki Ito, Yu Onoda, Patricia A. Kosian, Joseph J. Korte, Rodney D. Johnson, Taisen Iguchi, Sigmund J. Degitz
      Abstract: The Larval Amphibian Growth and Development Assay (LAGDA) is a globally harmonized chemical testing guideline developed by the U.S. Environmental Protection Agency in collaboration with Japan's Ministry of Environment to support risk assessment. The assay is employed as a higher tiered approach to evaluate effects of chronic chemical exposure throughout multiple life stages in a model amphibian species, Xenopus laevis. To evaluate the utility of the initial LAGDA design, the assay was performed using a mixed mode of action endocrine disrupting chemical, benzophenone‐2 (BP‐2). X. laevis embryos were exposed in flow‐through conditions to 0, 1.5, 3.0 or 6.0 mg l–1 BP‐2 until 2 months post‐metamorphosis. Overt toxicity was evident throughout the exposure period in the 6.0 mg l–1 treatment due to elevated mortality rates and observed liver and kidney pathologies. Concentration‐dependent increases in severity of thyroid follicular cell hypertrophy and hyperplasia occurred in larval tadpoles indicating BP‐2‐induced impacts on the thyroid axis. Additionally, gonads were impacted in all treatments with some genetic males showing both testis and ovary tissues (1.5 mg l–1) and 100% of the genetic males in the 3.0 and 6.0 mg l−1 treatments experiencing complete male‐to‐female sex reversal. Concentration‐dependent vitellogenin induction occurred in both genders with associated accumulations of protein in the livers, kidneys and gonads, which was likely vitellogenin and other estrogen‐responsive yolk proteins. This is the first study that demonstrates the endocrine effects of this mixed mode of action chemical in an amphibian species and demonstrates the utility of the LAGDA design for supporting chemical risk assessment. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-05-30T21:20:47.46234-05:0
      DOI: 10.1002/jat.3336
       
  • Preclinical safety study of a recombinant Streptococcus pyogenes vaccine
           formulated with aluminum adjuvant
    • Abstract: A recombinant vaccine composed of a fusion protein formulated with aluminum hydroxide adjuvant is under development for protection against diseases caused by Streptococcus pyogenes. The safety and local reactogenicity of the vaccine was assessed by a comprehensive series of clinical, pathologic and immunologic tests in preclinical experiments. Outbred mice received three intramuscular injections of 1/5th of the human dose (0.1 ml) and rabbits received two injections of the full human dose. Control groups received adjuvant or protein antigen. The vaccine did not cause clinical evidence of systemic toxicity in mice or rabbits. There was a transient increase of peripheral blood neutrophils after the third vaccination of mice. In addition, the concentration of acute phase proteins serum amyloid A and haptoglobin was significantly increased 1 day after injection of the vaccine in mice. There was mild transient swelling and erythema of the injection site in both mice and rabbits. Treatment‐related pathology was limited to inflammation at the injection site and accumulation of adjuvant‐containing macrophages in the draining lymph nodes. In conclusion, the absence of clinical toxicity in two animal species suggest that the vaccine is safe for use in a phase I human clinical trial. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-05-30T21:05:44.533104-05:
      DOI: 10.1002/jat.3349
       
  • Lithium limits trimethyltin‐induced cytotoxicity and proinflammatory
           response in microglia without affecting the concurrent autophagy
           impairment
    • Authors: Cinzia Fabrizi; Elena Pompili, Francesca Somma, Stefania De Vito, Viviana Ciraci, Marco Artico, Paola Lenzi, Francesco Fornai, Lorenzo Fumagalli
      Abstract: Trimethyltin (TMT) is a highly toxic molecule present as an environmental contaminant causing neurodegeneration particularly of the limbic system both in humans and in rodents. We recently described the occurrence of impairment in the late stages of autophagy in TMT‐intoxicated astrocytes. Here we show that similarly to astrocytes also in microglia, TMT induces the precocious block of autophagy indicated by the accumulation of the autophagosome marker, microtubule associated protein light chain 3. Consistent with autophagy impairment we observe in TMT‐treated microglia the accumulation of p62/SQSTM1, a protein specifically degraded through this pathway. Lithium has been proved effective in limiting neurodegenerations and, in particular, in ameliorating symptoms of TMT intoxication in rodents. In our in vitro model, lithium displays a pro‐survival and anti‐inflammatory action reducing both cell death and the proinflammatory response of TMT‐treated microglia. In particular, lithium exerts these activities without reducing TMT‐induced accumulation of light chain 3 protein. In fact, the autophagic block imposed by TMT is unaffected by lithium administration. These results are of interest as defects in the execution of autophagy are frequently observed in neurodegenerative diseases and lithium is considered a promising therapeutic agent for these pathologies. Thus, it is relevant that this cation can still maintain its pro‐survival and anti‐inflammatory role in conditions of autophagy block. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-05-25T23:20:33.492046-05:
      DOI: 10.1002/jat.3344
       
  • Toxic effects of chemical dispersant Corexit 9500 on water flea Daphnia
           magna
    • Authors: Kenji Toyota; Nicole A. McNabb, Demetri D. Spyropoulos, Taisen Iguchi, Satomi Kohno
      Abstract: In 2010, approximately 2.1 million gallons of chemical dispersants, mainly Corexit 9500, were applied in the Gulf of Mexico to prevent the oil slick from reaching shorelines and to accelerate biodegradation of oil during the Deepwater Horizon oil spill. Recent studies have revealed toxic effects of Corexit 9500 on marine microzooplankton that play important roles in food chains in marine ecosystems. However, there is still little known about the toxic effects of Corexit 9500 on freshwater zooplankton, even though oil spills do occur in freshwater and chemical dispersants may be used in response to these spills. The cladoceran crustacean, water flea Daphnia magna, is a well‐established model species for various toxicological tests, including detection of juvenile hormone‐like activity in test compounds. In this study, we conducted laboratory experiments to investigate the acute and chronic toxicity of Corexit 9500 using D. magna. The acute toxicity test was conducted according to OECD TG202 and the 48 h EC50 was 1.31 ppm (CIs 0.99–1.64 ppm). The reproductive chronic toxicity test was performed following OECD TG211 ANNEX 7 and 21 days LOEC and NOEC values were 4.0 and 2.0 ppm, respectively. These results indicate that Corexit 9500 has toxic effects on daphnids, particularly during the neonatal developmental stage, which is consistent with marine zooplankton results, whereas juvenile hormone‐like activity was not identified. Therefore, our findings of the adverse effects of Corexit 9500 on daphnids suggest that application of this type of chemical dispersant may have catastrophic impacts on freshwater ecosystems by disrupting the key food chain network. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-05-25T23:10:32.196468-05:
      DOI: 10.1002/jat.3343
       
  • Integrated approach to testing and assessment for predicting rodent
           genotoxic carcinogenicity
    • Authors: Petko I. Petkov; Terry W. Schultz, E. Maria Donner, Masamitsu Honma, Takeshi Morita, Shuichi Hamada, Akihiro Wakata, Masayuki Mishima, Jiro Maniwa, Milen Todorov, Elena Kaloyanova, Stefan Kotov, Ovanes G. Mekenyan
      Abstract: We investigated the performance of an integrated approach to testing and assessment (IATA), designed to cover different genotoxic mechanisms causing cancer and to replicate measured carcinogenicity data included in a new consolidated database. Genotoxic carcinogenicity was predicted based on positive results from at least two genotoxicity tests: one in vitro and one in vivo (which were associated with mutagenicity categories according to the Globally Harmonized System classification). Substances belonging to double positives mutagenicity categories were assigned to be genotoxic carcinogens. In turn, substances that were positive only in a single mutagenicity test were assigned to be mutagens. Chemicals not classified by the selected genotoxicity endpoints were assigned to be negative genotoxic carcinogens and subsequently evaluated for their capability to elicit non‐genotoxic carcinogenicity. However, non‐genotoxic carcinogenicity mechanisms were not currently included in the developed IATA. The IATA is docked to the OECD Toolbox and uses measured data for different genotoxicity endpoints when available. Alternatively, the system automatically provides predictions by SAR genotoxicity models using the OASIS Tissue Metabolism Simulator platform. When the developed IATA was tested against the consolidated database, its performance was found to be high, with sensitivity of 74% and specificity of 83%, when measured carcinogenicity data were used along with predictions falling within the models' applicability domains. Performance of the IATA would be slightly changed to a sensitivity of 80% and specificity of 72% when the evaluation by non‐genotoxic carcinogenicity mechanisms was taken into account. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-05-25T22:50:32.162628-05:
      DOI: 10.1002/jat.3338
       
  • Acetyl L‐carnitine targets adenosine triphosphate synthase in protecting
           zebrafish embryos from toxicities induced by verapamil and ketamine: An in
           vivo assessment
    • Authors: Xiaoqing Guo; Melanie Dumas, Bonnie L. Robinson, Syed F. Ali, Merle G. Paule, Qiang Gu, Jyotshna Kanungo
      Abstract: Verapamil is a Ca2+ channel blocker and is highly prescribed as an anti‐anginal, antiarrhythmic and antihypertensive drug. Ketamine, an antagonist of the Ca2+‐permeable N‐methyl‐d‐aspartate‐type glutamate receptors, is a pediatric anesthetic. Previously we have shown that acetyl l‐carnitine (ALCAR) reverses ketamine‐induced attenuation of heart rate and neurotoxicity in zebrafish embryos. Here, we used 48 h post‐fertilization zebrafish embryos that were exposed to relevant drugs for 2 or 4 h. Heart beat and overall development were monitored in vivo. In 48 h post‐fertilization embryos, 2 mm ketamine reduced heart rate in a 2 or 4 h exposure and 0.5 mm ALCAR neutralized this effect. ALCAR could reverse ketamine's effect, possibly through a compensatory mechanism involving extracellular Ca2+ entry through L‐type Ca2+ channels that ALCAR is known to activate. Hence, we used verapamil to block the L‐type Ca2+ channels. Verapamil was more potent in attenuating heart rate and inducing morphological defects in the embryos compared to ketamine at specific times of exposure. ALCAR reversed cardiotoxicity and developmental toxicity in the embryos exposed to verapamil or verapamil plus ketamine, even in the presence of 3,4,5‐trimethoxybenzoic acid 8‐(diethylamino)octyl ester, an inhibitor of intracellular Ca2+ release suggesting that ALCAR acts via effectors downstream of Ca2+. In fact, ALCAR's protective effect was blunted by oligomycin A, an inhibitor of adenosine triphosphate synthase that acts downstream of Ca2+ during adenosine triphosphate generation. We have identified, for the first time, using in vivo studies, a downstream effector of ALCAR that is critical in abrogating ketamine‐ and verapamil‐induced developmental toxicities. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.
      PubDate: 2016-05-18T07:05:10.31434-05:0
      DOI: 10.1002/jat.3340
       
  • Dibutyltin‐induced alterations of interleukin 1beta secretion from
           human immune cells
    • Authors: Shyretha Brown; Shahin Tehrani, Margaret M. Whalen
      Abstract: Dibutyltin (DBT) is used to stabilize polyvinyl chloride plastics (including pipes that distribute drinking water) and as a de‐worming agent in poultry. DBT is found in human blood, and DBT exposures alter the secretion of tumor necrosis factor alpha and interferon gamma from lymphocytes. Interleukin (IL)‐1β is a proinflammatory cytokine that regulates cellular growth, tissue restoration and immune response regulation. IL‐1β plays a role in increasing invasiveness of certain tumors. This study reveals that exposures to DBT (24 h, 48 h and 6 days) modify the secretion of IL‐1β from increasingly reconstituted preparations of human immune cells (highly enriched human natural killer cells, monocyte‐depleted [MD] peripheral blood mononuclear cells [PBMCs], PBMCs, granulocytes and a preparation combining both PBMCs and granulocytes). DBT altered IL‐1β secretion from all cell preparations. Higher concentrations of DBT (5 and 2.5 μm) decreased the secretion of IL‐1β, while lower concentrations of DBT (0.1 and 0.05 μm) increased the secretion of IL‐1β. Selected signaling pathways were examined in MD‐PBMCs to determine if they play a role in DBT‐induced elevations of IL‐1β secretion. Pathways examined were IL‐1β converting enzyme (caspase 1), mitogen‐activated protein kinases and nuclear factor kappa B. Caspase 1 and mitogen‐activated protein kinase pathways appear to be utilized by DBT in increasing IL‐1β secretion. These results indicate that DBT alters IL‐1β secretion from human immune cells in an ex. vivo system utilizing several IL‐1β regulating signaling pathways. Thus, DBT may have the potential to alter IL‐1β secretion in an in vivo system. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-05-17T01:35:28.9227-05:00
      DOI: 10.1002/jat.3339
       
  • Revision of the affinity constant for perchlorate binding to the
           sodium‐iodide symporter based on in vitro and human in vivo data
    • Authors: Paul M. Schlosser
      Abstract: A series of previously published physiologically based pharmacokinetic (PBPK) models describe the effect of perchlorate on iodide uptake by the thyroid, with the mechanism being competitive inhibition of iodide transport by the sodium‐iodide symporter (NIS). Hence a key parameter of these models is the affinity of perchlorate for the NIS, characterized as the Michaelis–Menten kinetic constant, Km. However, when model predictions were compared to published results of a human study measuring radio‐iodide uptake (RAIU) inhibition after controlled perchlorate exposures, it was found to only fit the lowest exposure level and underpredicted RAIU inhibition at higher levels. Published in vitro data, in which perchlorate‐induced inhibition of iodide uptake via the NIS was measured, were re‐analyzed. Km for binding of perchlorate to the NIS originally derived from these data, 1.5 μm, had been obtained using Lineweaver–Burk plots, which allow for linear regression but invert the signal–noise of the data. Re‐fitting these data by non‐linear regression of the non‐inverted data yielded a 60% lower value for the Km, 0.59 μm. Substituting this value into the PBPK model for an average adult human significantly improved model agreement with the human RAIU data for exposures
      PubDate: 2016-05-13T08:40:22.50649-05:0
      DOI: 10.1002/jat.3337
       
  • Non‐clinical safety assessment of single and repeated administration of
           gE/AS01 zoster vaccine in rabbits
    • Abstract: HZ/su is an investigational recombinant subunit vaccine for the prevention of shingles, a disease resulting from the reactivation of varicella zoster virus. The vaccine is composed of recombinant varicella zoster virus glycoprotein E (gE), and liposome‐based Adjuvant System AS01. To evaluate the potential local and systemic effects of this vaccine, three studies were performed in rabbits. In the first two studies, rabbits received a single intramuscular (IM; study 1) or subcutaneous (SC; study 2) dose of gE/AS01, AS01 alone (in study 2 only) or saline, and the local tolerance was evaluated up to 3 days after administration. Under these conditions, only local inflammatory reactions at the injection sites were detected by microscopic evaluation. In the third study, gE/AS01, AS01 alone or saline, were injected SC or IM on four occasions at 2 week intervals. General health status, local tolerance, ophthalmology, haematology and blood chemistry parameters were monitored. Macroscopic and microscopic evaluations were performed after termination of the study. The only treatment‐related changes included a transient increase in neutrophils, C‐reactive protein and fibrinogen levels and microscopic signs of inflammation at the injection sites, which are expected observations related to the elicited inflammatory reaction. The SC and IM routes of administration produced similar systemic effects. However, microscopic findings at the injection sites differed. One month after the last injection, recovery was complete in all groups. In conclusion, the single and repeated SC and IM administration of the gE/AS01 vaccine were locally and systemically well‐tolerated in rabbits and support the clinical development of the vaccine. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-05-12T08:03:54.99173-05:0
      DOI: 10.1002/jat.3329
       
  • 4‐Nitrophenol exposure alters the AhR signaling pathway and related gene
           expression in the rat liver
    • Authors: Ruonan Li; Meiyan Song, Zhi Li, Yansen Li, Gen Watanabe, Kentaro Nagaoka, Kazuyoshi Taya, Chunmei Li
      Abstract: 4‐Nitrophenol (PNP) is well known as an environmental endocrine disruptor. The aim of this study was to clarify the mechanism of PNP‐induced liver damage and determine the regulatory involvement of the aryl hydrocarbon receptor (AhR) signaling pathway and associated gene expression. Immature male Wistar–Imamichi rats (28 days old) were randomly divided into control and PNP groups, which consisted of 1‐ and 3‐day exposure (1 DE and 3 DE, respectively) and 3‐day exposure followed by 3‐day recovery (3 DE + 3 DR), groups. Each group was administered the vehicle or PNP (200 mg kg–1 body weight). The body and liver weight were significantly decreased in the 3 DE group. The mRNA expression levels of estrogen receptor‐α (ERα), glutathione S‐transferase (GST) and AhR exhibited a significant increase in the 1 DE group whereas, in contrast, that of cytochrome P450 (CYP) 1A1 decreased significantly in the 3 DE +3 DR group. AhR and CYP1A1 proteins were detected in the cytoplasm of hepatocytes of the 1 DE and 3 DE +3 DR groups whereas the ERα protein was found in the hepatocyte nuclei of the 1 DE and 3 DE groups. The present study demonstrates that PNP activated the AhR signaling pathway and regulated related CYP1A1 and GST gene expression in the liver. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-05-12T07:51:04.421728-05:
      DOI: 10.1002/jat.3332
       
  • Lack of genotoxic mechanisms in early‐stage furan‐induced
           hepatocellular tumorigenesis in gpt delta rats
    • Authors: Daisuke Hibi; Yu Yokoo, Yuta Suzuki, Yuji Ishii, Meilan Jin, Aki Kijima, Takehiko Nohmi, Akiyoshi Nishikawa, Takashi Umemura
      Abstract: Furan has been used as an intermediate in the chemical‐manufacturing industry and has been shown to contaminate various foods. Although furan induces hepatocellular tumors in rodents, equivocal results from in vitro and in vivo mutagenicity tests have caused controversy regarding the involvement of genotoxic mechanisms in furan‐induced carcinogenesis. In the present study, to elucidate the possible mechanisms underlying furan‐induced hepatocarcinogenesis, a comprehensive medium‐term analysis was conducted using gpt delta rats treated with furan at carcinogenic doses for 13 weeks. In the liver, the frequencies of gpt and Spi‐ mutants derived mainly from point and deletion mutations, respectively, were not changed, and there were no furan‐specific gpt mutations in furan‐treated rats. In contrast, the number and area of glutathione S‐transferase placental form (GST‐P)‐ positive foci were significantly increased in the high‐dose group. Also, the ratio of PCNA‐positive hepatocytes was significantly elevated in the same group, as supported by significant increases in cyclin d1 and cyclin e1 mRNA levels. Thus, it is highly probable that cell proliferation, but not genotoxic mechanisms, contribute to the development of GST‐P foci in furan‐treated rats. Based on the close relationship between GST‐P and neoplastic hepatocytes, these data allowed us to hypothesize that cell proliferation following signal transduction other than the mitogen‐activated protein kinase (MAPK)/ERK pathway may play a crucial role in early‐stage furan‐induced hepatocarcinogenesis. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-05-03T07:51:06.035242-05:
      DOI: 10.1002/jat.3331
       
  • Development of the Larval Amphibian Growth and Development Assay: effects
           of chronic 4‐tert‐octylphenol or 17β‐trenbolone exposure in Xenopus
           laevis from embryo to juvenile
    • Authors: Jonathan T. Haselman; Patricia A. Kosian, Joseph J. Korte, Allen W. Olmstead, Taisen Iguchi, Rodney D. Johnson, Sigmund J. Degitz
      Abstract: The Larval Amphibian Growth and Development Assay (LAGDA) is a globally harmonized test guideline developed by the U.S. Environmental Protection Agency in collaboration with Japan's Ministry of the Environment. The LAGDA was designed to evaluate apical effects of chronic chemical exposure on growth, thyroid‐mediated amphibian metamorphosis and reproductive development. During the validation phase, two well‐characterized endocrine‐disrupting chemicals were tested to evaluate the performance of the initial assay design: xenoestrogen 4‐tert‐octylphenol (tOP) and xenoandrogen 17β‐trenbolone (TB). Xenopus laevis embryos were exposed, in flow‐through conditions, to tOP (nominal concentrations: 0.0, 6.25, 12.5, 25 and 50 µg l–1) or TB (nominal concentrations: 0.0, 12.5, 25, 50 and 100 ng l–1) until 8 weeks post‐metamorphosis, at which time growth measurements were taken, and histopathology assessments were made of the gonads, reproductive ducts, liver and kidneys. There were no effects on growth in either study and no signs of overt toxicity, sex reversal or gonad dysgenesis. Exposure to tOP caused a treatment‐related decrease in circulating thyroxine and an increase in thyroid follicular cell hypertrophy and hyperplasia (25 and 50 µg l–1) during metamorphosis. Müllerian duct development was affected after exposure to both chemicals; tOP exposure caused dose‐dependent maturation of oviducts in both male and female frogs, whereas TB exposure caused accelerated Müllerian duct regression in males and complete regression in >50% of the females in the 100 ng l–1 treatment. Based on these results, the LAGDA performed adequately to evaluate apical effects of chronic exposure to two endocrine‐active compounds and is the first standardized amphibian multiple life stage toxicity test to date. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.
      PubDate: 2016-05-03T07:51:03.166644-05:
      DOI: 10.1002/jat.3330
       
  • Characterization of three human cell line models for high‐throughput
           neuronal cytotoxicity screening
    • Abstract: More than 75 000 man‐made chemicals contaminate the environment; many of these have not been tested for toxicities. These chemicals demand quantitative high‐throughput screening assays to assess them for causative roles in neurotoxicities, including Parkinson's disease and other neurodegenerative disorders. To facilitate high throughput screening for cytotoxicity to neurons, three human neuronal cellular models were compared: SH‐SY5Y neuroblastoma cells, LUHMES conditionally‐immortalized dopaminergic neurons, and Neural Stem Cells (NSC) derived from human fetal brain. These three cell lines were evaluated for rapidity and degree of differentiation, and sensitivity to 32 known or candidate neurotoxicants. First, expression of neural differentiation genes was assayed during a 7‐day differentiation period. Of the three cell lines, LUHMES showed the highest gene expression of neuronal markers after differentiation. Both in the undifferentiated state and after 7 days of neuronal differentiation, LUHMES cells exhibited greater cytotoxic sensitivity to most of 32 suspected or known neurotoxicants than SH‐SY5Y or NSCs. LUHMES cells were also unique in being more susceptible to several compounds in the differentiating state than in the undifferentiated state; including known neurotoxicants colchicine, methyl‐mercury (II), and vincristine. Gene expression results suggest that differentiating LUHMES cells may be susceptible to apoptosis because they express low levels of anti‐apoptotic genes BCL2 and BIRC5/survivin, whereas SH‐SY5Y cells may be resistant to apoptosis because they express high levels of BCL2, BIRC5/survivin, and BIRC3 genes. Thus, LUHMES cells exhibited favorable characteristics for neuro‐cytotoxicity screening: rapid differentiation into neurons that exhibit high level expression neuronal marker genes, and marked sensitivity of LUHMES cells to known neurotoxicants. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-05-03T07:44:26.906766-05:
      DOI: 10.1002/jat.3334
       
  • Regucalcin counteracts tert‐butyl hydroperoxide and cadmium‐induced
           oxidative stress in rat testis
    • Abstract: Regucalcin (RGN) is a calcium (Ca2+)‐binding protein with multiple physiological roles and has also been linked to the suppression of oxidative stress. It is widely known that oxidative stress adversely affects spermatogenesis, disrupting the development of germ cells, and interfering with sperm function. The present study aims to analyze the role of RGN modulating testicular oxidative stress. To address this issue, seminiferous tubules (SeT) from transgenic rats overexpressing RGN (Tg‐RGN) and wild‐type (WT) were cultured ex vivo for 24 h in the presence/absence of pro‐oxidant stimuli, tert‐butyl hydroperoxide (TBHP, 250 and 500 μM) and cadmium chloride (Cd, 10 and 20 μM). Noteworthy, SeT from Tg‐RGN animals displayed a significantly higher antioxidant capacity and diminished levels of thiobarbituric acid reactive substances relatively to their WT counterparts, both in control and experimental conditions. Regarding the antioxidant defense systems, a significant increase in the activity of glutathione‐S‐transferase was found in the SeT of Tg‐RGN whereas no differences were observed in superoxide dismutase activity throughout experimental conditions. The activity of apoptosis executioner caspase‐3 was significantly increased in the SeT of WT rats treated with 250 μM of TBHP or 10 μM of Cd, an effect not seen in Tg‐RGN animals. These results showed that the SeT of Tg‐RGN animals displayed lower levels of oxidative stress and increased antioxidant defenses, exhibiting protection against oxidative damage and apoptosis. Moreover, the present findings support the antioxidant role of RGN in spermatogenesis, which may be an important issue of further research in the context of male infertility. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-04-25T02:46:48.66054-05:0
      DOI: 10.1002/jat.3333
       
  • Biodistribution of polyacrylic acid‐coated iron oxide nanoparticles is
           associated with proinflammatory activation and liver toxicity
    • Abstract: Iron oxide nanoparticles (IONs) have physical and chemical properties that render them useful for several new biomedical applications. Still, so far, in vivo safety studies of IONs with coatings of biomedical interest are still scarce. The aim of this study, therefore, was to clarify the acute biological effects of polyacrylic acid (PAA)‐coated IONs, by determining their biodistribution and their potential proinflammatory and toxic effects in CD‐1 mice. The biodistribution of PAA‐coated IONs in several organs (liver, spleen, kidneys, brain, heart, testes and lungs), the plasma cytokines, chemokine and aminotransferases levels, white blood cell count, oxidative stress parameters, adenosine triphosphate and histologic features of liver, spleen and kidneys were evaluated 24 h after a single acute (8, 20 or 50 mg kg−1) intravenous administration of PAA‐coated IONs in magnetite form. The obtained results showed that these IONs accumulate mainly in the liver and spleen and, to a lesser extent, in the lungs. Although our data showed that PAA‐coated IONs do not cause severe organ damage, an inflammatory process was triggered in vivo, as evidenced by as evidenced by increased neutrophils and large lymphocytes in the differential blood count. Moreover, an accumulation of iron in macrophages of the liver and spleen was observed and hepatic lipid peroxidation was elicited, showing that the IONs are able to induce oxidative stress. The effects of these nanoparticles need to be further investigated regarding the mechanisms involved and the long‐term consequences of intravenous administration of PAA‐coated IONs. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-04-22T04:16:14.285691-05:
      DOI: 10.1002/jat.3323
       
  • Neuroglial alterations in the zebrafish brain exposed to cadmium chloride
    • Authors: Antonio Monaco; Maria C. Grimaldi, Ida Ferrandino
      Abstract: Cadmium is an extremely toxic heavy metal that widely occurs in industrial workplaces with various hazardous effects on brain functions. The cytotoxic effects of cadmium chloride (CdCl2) on the neuroglial components of the zebrafish brain were analysed by detecting the glial fibrillary acidic protein (GFAP) expression and the mRNA levels of myelin genes mbp, mpz and plp1 in adult specimens exposed to cadmium for 2, 7 and 16 days. A significant decrease in the GFAP protein by Western blotting experiments was observed after 2 days of treatment, reaching 55% after 16 days. No change was observed in the mRNA levels. Using immunohistochemistry, a reduction in GFAP‐positive structures was revealed with a progressive trend in all the brains at 2, 7 and 16 days of treatment. In particular, a considerable reduction in GFAP‐positive fibres, with a different course, was observed in the ventricle areas and at the pial surface and in blood vessels after 16 days. Our experiments also showed a structural and chemical alteration of myelin and upregulation of mpz mRNA levels, the oligodendrocyte gene that is upregulated in experiments of neuronal injury, but not of plp1 and mbp mRNA levels, other myelin structural genes. These data confirm the toxic action of cadmium on the zebrafish brain. This action is time‐dependent and involves the glial cells, key components of the protection and function of nerve cells, hence the basis for many neurological diseases. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-04-15T04:01:49.760995-05:
      DOI: 10.1002/jat.3328
       
  • Impact of silver nanoparticles on marine diatom Skeletonema costatum
    • Authors: Jun Huang; Jinping Cheng, Jun Yi
      Abstract: When silver nanoparticles (AgNPs) are used commercially at a large scale, they infiltrate the environment at a rapid pace. However, the impact of large quantities of AgNPs on aquatic ecosystems is still largely unknown. In aquatic ecosystems, the phytoplanktons have a vital ecological function and, therefore, the potential impact of AgNPs on the microalgae community has elicited substantial concern. Therefore, in this study, the impacts of AgNPs on a marine diatom, the Skeletonema costatum, are investigated, with a focus on their photosynthesis and associated mechanisms. Exposure to AgNPs at a concentration of 0.5 mg l−1 significantly induces excess intracellular reactive oxygen species (ROS, 122%) and reduces 28% of their cell viability. More importantly, exposure to AgNPs reduces the algal chlorophyll‐a content. Scanning electron microscopy (SEM) was conducted, which revealed that AgNPs obstruct the light absorption of algae because they adhere to their surface. The maximum photochemical efficiency of photosystem II (Fv/Fm) demonstrates that exposure to AgNPs significantly inhibits the conversion of light energy into photosynthetic electron transport. Moreover, the genes of the photosystem II reaction center protein (D1) are significantly down‐regulated (P 
      PubDate: 2016-04-15T03:56:09.579116-05:
      DOI: 10.1002/jat.3325
       
  • Accounting for data variability, a key factor in in vivo/in vitro
           relationships: application to the skin sensitization potency (in vivo LLNA
           versus in vitro DPRA) example
    • Authors: S. Dimitrov; A. Detroyer, C. Piroird, C. Gomes, J. Eilstein, T. Pauloin, C. Kuseva, H. Ivanova, I. Popova, Y. Karakolev, S. Ringeissen, O. Mekenyan
      Abstract: When searching for alternative methods to animal testing, confidently rescaling an in vitro result to the corresponding in vivo classification is still a challenging problem. Although one of the most important factors affecting good correlation is sample characteristics, they are very rarely integrated into correlation studies. Usually, in these studies, it is implicitly assumed that both compared values are error‐free numbers, which they are not. In this work, we propose a general methodology to analyze and integrate data variability and thus confidence estimation when rescaling from one test to another. The methodology is demonstrated through the case study of rescaling the in vitro Direct Peptide Reactivity Assay (DPRA) reactivity to the in vivo Local Lymph Node Assay (LLNA) skin sensitization potency classifications. In a first step, a comprehensive statistical analysis evaluating the reliability and variability of LLNA and DPRA as such was done. These results allowed us to link the concept of gray zones and confidence probability, which in turn represents a new perspective for a more precise knowledge of the classification of chemicals within their in vivo OR in vitro test. Next, the novelty and practical value of our methodology introducing variability into the threshold optimization between the in vitro AND in vivo test resides in the fact that it attributes a confidence probability to the predicted classification. The methodology, classification and screening approach presented in this study are not restricted to skin sensitization only. They could be helpful also for fate, toxicity and health hazard assessment where plenty of in vitro and in chemico assays and/or QSARs models are available. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-04-15T03:45:36.191466-05:
      DOI: 10.1002/jat.3318
       
  • A 28‐year observational study of urinary cadmium and β2‐microglobulin
           concentrations in inhabitants in cadmium‐polluted areas in Japan
    • Authors: Hoang Duc Phuc; Teruhiko Kido, Ho Dung Manh, Le Thai Anh, Nguyen Thi Phuong Oanh, Rie Okamoto, Akie Ichimori, Kazuhiro Nogawa, Yasushi Suwazono, Hideaki Nakagawa
      Abstract: The biological half‐life of cadmium (Cd) is as long as 10–30 years. Exposure to this element induces renal tubular dysfunction, which is considered irreversible. β2‐microglobulin (β2‐MG) is a low‐molecular‐weight protein, and urinary β2‐MG is one of the most useful and critical indicators for the early detection of renal tubular dysfunction. However, very little research has been published concerning the long‐term observation of Cd‐induced adverse health effects. As such, this follow‐up study was conducted for 28 years to clarify the relationship between the concentration of Cd and β2‐MG in the urine of 28 inhabitants (14 male and 14 female) living in the Kakehashi River basin, Ishikawa prefecture (Japan), previously one of the most highly Cd‐polluted regions in this country. All subjects were over 60 years old in 2014 and participated in all six health examinations conducted over 28 years (1986–2014). Urine was collected at the appropriate time and kept frozen to analyze urinary Cd and β2‐MG concentrations. The urinary Cd concentration was found to decrease by nearly half between 1986 and 2008 in both male and female subjects, whereas it increased significantly from 2008 to 2014 in males. In contrast, urinary β2‐MG concentrations tended to increase over the 28‐year study period in both sexes. Urinary Cd and β2‐MG concentrations in females were significantly higher than those in males in this Cd‐polluted region. Age is more strongly associated with urinary β2‐MG concentration than recent Cd body burden. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-04-15T02:36:12.90087-05:0
      DOI: 10.1002/jat.3327
       
  • Airborne nanoparticles (PM0.1) induce autophagic cell death of human
           neuronal cells
    • Abstract: Airborne nanoparticles PM0.1 (
      PubDate: 2016-04-15T01:51:59.577605-05:
      DOI: 10.1002/jat.3324
       
  • MicroRNA profiles in a monkey testicular injury model induced by
           testicular hyperthermia
    • Authors: Ken Sakurai; Kei Mikamoto, Makoto Shirai, Takuma Iguchi, Kazumi Ito, Wataru Takasaki, Kazuhiko Mori
      Abstract: To characterize microRNAs (miRNAs) involved in testicular toxicity in cynomolgus monkeys, miRNA profiles were investigated using next‐generation sequencing (NGS), microarray and reverse transcription‐quantitative real‐time‐PCR (RT‐qPCR) methods. First, to identify organ‐specific miRNAs, we compared the expression levels of miRNAs in the testes to those in representative organs (liver, heart, kidney, lung, spleen and small intestine) obtained from naïve mature male and female monkeys (n = 2/sex) using NGS analysis. Consequently, miR‐34c‐5p, miR‐202‐5p, miR‐449a and miR‐508‐3p were identified to be testicular‐specific miRNAs in cynomolgus monkeys. Next, we investigated miRNA profiles after testicular–hyperthermia (TH) treatment to determine which miRNAs are involved in testicular injury. In this experiment, mature male monkeys were divided into groups with or without TH‐treatment (n = 3/group) by immersion of the testes in a water bath at 43 °C for 30 min for 5 consecutive days. As a result, TH treatment induced testicular injury in all animals, which was characterized by decreased numbers of spermatocytes and spermatids. In a microarray analysis of the testis, 11 up‐regulated (>2.0 fold) and 13 down‐regulated (
      PubDate: 2016-04-12T21:45:55.640689-05:
      DOI: 10.1002/jat.3326
       
  • Accessing the molecular interactions of phthalates and their primary
           metabolites with the human pregnane X receptor using in silico profiling
    • Authors: M. K. Sarath Josh; S. Pradeep, Aparna K. Balan, M. N. Sreejith, Sailas Benjamin
      Abstract: Phthalates are known to cause endocrine disruption in humans and animals. Being lipophilic xenobiotic chemicals, phthalates from the surrounding environments can easily be absorbed into the biological system, thereby causing various health dysfunctions. This molecular docking study evaluates a variety of molecular interactions of 12 commonly used diphthalates and respective monophthalates onto the ligand binding domain (LBD) of the human pregnane X receptor (hPXR), a xenosensor, which would be beneficial for further in vitro and in vivo studies on hazardous phthalates. Out of 12 diphthalates and their monophthalates tested, diisodecyl phthalate (–9.16 kcal mol–1) showed more affinity toward hPXR whereas diisononyl phthalate (–8.77) and di(2‐ethyhexyl)phthalate (–8.56), the predominant plasticizers found in a variety of plastics and allied products, showed comparable binding scores with that of the control ligands such as hyperforine (–9.99) and dexamethasone (–7.36). In addition to the above diphthalates, some of their monophthalates (monoisodecyl phthalate, mono‐2‐etheylhexyl phthalate, etc.) also established similar interactions with certain crucial amino acids in the LBD, which led to higher G scores. In fact, bisphenol A, a well‐studied and proven endocrine disruptor, showed lesser G scores (–6.69) than certain phthalates. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-04-12T21:21:30.335434-05:
      DOI: 10.1002/jat.3321
       
  • Pyrazinamide induced hepatic injury in rats through inhibiting the
           PPARα pathway
    • Abstract: Pyrazinamide (PZA) causes serious hepatotoxicity, but little is known about the exact mechanism by which PZA induced liver injury. The peroxisome proliferator‐activated receptors alpha (PPARα) is highly expressed in the liver and modulates the intracellular lipidmetabolism. So far, the role of PPARα in the hepatotoxicity of PZA is unknown. In the present study, we described the hepatotoxic effects of PZA and the role of PPARα and its target genes in the downstream pathway including L‐Fabp, Lpl, Cpt‐1b, Acaa1, Apo‐A1 and Me1 in this process. We found PZA induced the liver lipid metabolism disorder and PPARα expressionwas down‐regulated which had a significant inverse correlation with liver injury degree. These changeswere ameliorated by fenofibrate, the co‐treatment that acts as a PPARα agonist. In contrast, short‐termstarvation significantly aggravated the severity of PZA‐induced liver injury. In conclusion, this study demonstrated the critical role played by PPARα in PZA‐induced hepatotoxicity and provided a better understanding of the molecular mechanisms underlying PZA‐induced liver injury. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-04-12T21:16:46.631941-05:
      DOI: 10.1002/jat.3319
       
  • Polymatin A from Smallanthus macroscyphus leaves: A safe and promising
           antidiabetic compound
    • Abstract: Smallanthus macroscyphus is an herb native to South America whose leaves are a source of antidiabetic compounds, although complete information about their safe use is not available yet. This study was developed to evaluate the toxicity profile of both 10% decoction and the sesquiterpene lactone polymatin A from S. macroscyphus leaves through in vitro cytotoxicity assays and in vivo subchronic oral toxicity. Cell viability of Hep‐G2, COS1, CHO‐K1 and Vero cell lines decreased in a concentration‐dependent manner when cells were incubated with 0.4–200 μg ml–1 of dry extract or 0.12–60 μg ml–1 of polymatin A. In subchronic studies, decoction was orally administered to Wistar rats for 90 days at daily doses of 70, 140 and 280 mg kg–1 of dry extract, whereas polymatin A was administered in the same way at doses of 7, 14 and 28 mg kg–1. No toxicity signs or deaths were observed. There were no changes in the behavior, body or organ weights, hematological, biochemical or urine parameters of the rats. No histopathological lesions were observed in the examined organs. The results indicate that the 10% decoction and polymatin A from S. macroscyphus leaves may be considered as non‐toxic substances at a wide range of doses, including the effective hypoglycemic dose. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-04-07T01:15:44.738352-05:
      DOI: 10.1002/jat.3312
       
  • Issue Information ‐ TOC
    • Pages: 1247 - 1249
      Abstract: No abstract is available for this article.
      PubDate: 2016-08-08T09:57:40.729943-05:
      DOI: 10.1002/jat.3244
       
  • Pluripotent stem cells: An in vitro model for nanotoxicity assessments
    • Authors: Harish K. Handral; Huei Jinn Tong, Intekhab Islam, Gopu Sriram, Vinicus Rosa, Tong Cao
      First page: 1250
      Abstract: The advent of technology has led to an established range of engineered nanoparticles that are used in diverse applications, such as cell–cell interactions, cell–material interactions, medical therapies and the target modulation of cellular processes. The exponential increase in the utilization of nanomaterials and the growing number of associated criticisms has highlighted the potential risks of nanomaterials to human health and the ecosystem. The existing in vivo and in vitro platforms show limitations, with fluctuations being observed in the results of toxicity assessments. Pluripotent stem cells (PSCs) are viable source of cells that are capable of developing into specialized cells of the human body. PSCs can be efficiently used to screen new biomaterials/drugs and are potential candidates for studying impairments of biophysical morphology at both the cellular and tissue levels during interactions with nanomaterials and for diagnosing toxicity. Three‐dimensional in vitro models obtained using PSC‐derived cells would provide a realistic, patient‐specific platform for toxicity assessments and in drug screening applications. The current review focuses on PSCs as an alternative in vitro platform for assessing the hazardous effects of nanomaterials on health systems and highlights the importance of PSC‐derived in vitro platforms. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-05-30T21:25:25.567452-05:
      DOI: 10.1002/jat.3347
       
  • Nanosuspension formulations of poorly water‐soluble compounds for
           intravenous administration in exploratory toxicity studies: in vitro and
           in vivo evaluation
    • Authors: Hisako Fujimura; Takao Komasaka, Taizo Tomari, Yasunori Kitano, Kouji Takekawa
      Pages: 1259 - 1267
      Abstract: This study was conducted to investigate the use of a nanosuspension for intravenous injection into dogs to increase exposure without toxic additives for preclinical studies in the discovery stage. Nanosuspensions were prepared with a mixer mill and zirconia beads with a vehicle of 2% (w/v) poloxamer 338, which was confirmed to lead to no histamine release in dogs. Sterilized nanosuspensions of poorly water‐soluble compounds, cilostazol (Cil), spironolactone (Spi) and probucol (Pro), at 10 mg ml−1 were obtained by milling for 30 min, followed by autoclaving for 20 min at 121 °C and milling for 30 min (mill–autoclave–mill method). The particle sizes (d50) of Cil, Spi and Pro were 0.554, 0.484 and 0.377 µm, respectively, and the percentages of the nominal concentration were 79.1%, 99.6% and 75.4%, respectively. In chromatographic data, no extra peaks were observed. The particle size of Cil was 0.564 µm after storage for 16 days at 2–8 °C. Cil in nanosuspension, but not in microsuspension, rapidly dissolved in dog plasma. Cil nanosuspension at 0.4 mg kg−1 and Cil saline solution at 0.03 mg kg−1, around the saturation solubility, were intravenously administered to dogs. Nanosuspension increased exposure. The versatility of the mill–autoclave–mill method was checked for 15 compounds, and the particle size of 12 compounds was in the nano range. The nanosuspension optimized in this study may be useful for intravenous toxicological and pharmacological studies in the early stage of drug development. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-02-05T05:35:05.545267-05:
      DOI: 10.1002/jat.3280
       
  • Quantitative evaluation of local pulmonary distribution of TiO2 in rats
           following single or multiple intratracheal administrations of TiO2
           nanoparticles using X‐ray fluorescence microscopy
    • Authors: Guihua Zhang; Naohide Shinohara, Hirokazu Kano, Hideki Senoh, Masaaki Suzuki, Takeshi Sasaki, Shoji Fukushima, Masashi Gamo
      Pages: 1268 - 1275
      Abstract: Uneven pulmonary nanoparticle (NP) distribution has been described when using single‐dose intratracheal administration tests. Multiple‐dose intratracheal administrations with small quantities of NPs are expected to improve the unevenness of each dose. The differences in local pulmonary NP distribution (called microdistribution) between single‐ and multiple‐dose administrations may cause differential pulmonary responses; however, this has not been evaluated. Here, we quantitatively evaluated the pulmonary microdistribution (per mesh: 100 μm × 100 μm) of TiO2 in lung sections from rats following one, two, three, or four doses of TiO2 NPs at a same total dosage of 10 mg kg−1 using X‐ray fluorescence microscopy. The results indicate that: (i) multiple‐dose administrations show lower variations in TiO2 content (ng mesh−1) for sections of each lobe; (ii) TiO2 appears to be deposited more in the right caudal and accessory lobes located downstream of the administration direction of NP suspensions, and less so in the right middle lobes, irrespective of the number of doses; (iii) there are not prominent differences in the pattern of pulmonary TiO2 microdistribution between rats following single and multiple doses of TiO2 NPs. Additionally, the estimation of pulmonary TiO2 deposition for multiple‐dose administrations imply that every dose of TiO2 would be randomly deposited only in part of the fixed 30–50% of lung areas. The evidence suggests that multiple‐dose administrations do not offer remarkable advantages over single‐dose administration on the pulmonary NP microdistribution, although multiple‐dose administrations may reduce variations in the TiO2 content for each lung lobe. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-02-16T06:44:51.139091-05:
      DOI: 10.1002/jat.3287
       
  • Oxidative stress and lung pathology following geogenic dust exposure
    • Authors: M. Leetham; J. DeWitt, B. Buck, D. Goossens, Y. Teng, J. Pollard, B. McLaurin, R. Gerads, D. Keil
      Pages: 1276 - 1283
      Abstract: This study was designed to evaluate markers of systemic oxidative stress and lung histopathology following subacute exposure to geogenic dust with varying heavy metal content collected from a natural setting prone to wind erosion and used heavily for off‐road vehicle recreation. Adult female B6C3F1 mice were exposed to several concentrations of dust collected from seven different types of surfaces at the Nellis Dunes Recreation Area in Clark County, Nevada, designated here as CBN 1‐7. Dust representing each of the seven surface types, with an average median diameter of 4.2 μm, was selected and administered via oropharyngeal aspiration to mice at concentrations from 0.01 to 100 mg of dust kg–1 of body weight. Exposures were given four times spaced a week apart over a 28 day period to mimic a month of weekend exposures. Lung pathology was evaluated while plasma markers of oxidative stress included levels of reactive oxygen and nitrogen species, superoxide dismutase, total antioxidant capacity and total glutathione. Overall, results of these assays to evaluate markers of oxidative stress indicate that no single CBN surface type was able to consistently induce markers of systemic oxidative stress at a particular dose or in a dose–response manner. All surface types were able to induce some level of lung inflammation, typically at the highest exposure levels. These data suggest that dust from the Nellis Dunes Recreation Area may present a potential health risk, but additional studies are necessary to characterize the full extent of health risks to humans. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-02-29T06:29:37.960919-05:
      DOI: 10.1002/jat.3297
       
  • Differential cytotoxicity of copper ferrite nanoparticles in different
           human cells
    • Pages: 1284 - 1293
      Abstract: Copper ferrite nanoparticles (NPs) have the potential to be applied in biomedical fields such as cell labeling and hyperthermia. However, there is a lack of information concerning the toxicity of copper ferrite NPs. We explored the cytotoxic potential of copper ferrite NPs in human lung (A549) and liver (HepG2) cells. Copper ferrite NPs were crystalline and almost spherically shaped with an average diameter of 35 nm. Copper ferrite NPs induced dose‐dependent cytotoxicity in both types of cells, evident by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazoliumbromide and neutral red uptake assays. However, we observed a quite different susceptibility in the two kinds of cells regarding toxicity of copper ferrite NPs. Particularly, A549 cells showed higher susceptibility against copper ferrite NP exposure than those of HepG2 cells. Loss of mitochondrial membrane potential due to copper ferrite NP exposure was observed. The mRNA level as well as activity of caspase‐3 enzyme was higher in cells exposed to copper ferrite NPs. Cellular redox status was disturbed as indicated by induction of reactive oxygen species (oxidant) generation and depletion of the glutathione (antioxidant) level. Moreover, cytotoxicity induced by copper ferrite NPs was efficiently prevented by N‐acetylcysteine treatment, which suggests that reactive oxygen species generation might be one of the possible mechanisms of cytotoxicity caused by copper ferrite NPs. To the best of our knowledge, this is the first report showing the cytotoxic potential of copper ferrite NPs in human cells. This study warrants further investigation to explore the mechanisms of differential toxicity of copper ferrite NPs in different types of cells. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-02-25T06:25:05.26449-05:0
      DOI: 10.1002/jat.3299
       
  • Optimization of an air–liquid interface exposure system for assessing
           toxicity of airborne nanoparticles
    • First page: 1294
      Abstract: The use of refined toxicological methods is currently needed for characterizing the risks of airborne nanoparticles (NPs) to human health. To mimic pulmonary exposure, we have developed an air–liquid interface (ALI) exposure system for direct deposition of airborne NPs on to lung cell cultures. Compared to traditional submerged systems, this allows more realistic exposure conditions for characterizing toxicological effects induced by airborne NPs. The purpose of this study was to investigate how the deposition of silver NPs (AgNPs) is affected by different conditions of the ALI system. Additionally, the viability and metabolic activity of A549 cells was studied following AgNP exposure. Particle deposition increased markedly with increasing aerosol flow rate and electrostatic field strength. The highest amount of deposited particles (2.2 μg cm–2) at cell‐free conditions following 2 h exposure was observed for the highest flow rate (390 ml min–1) and the strongest electrostatic field (±2 kV). This was estimated corresponding to deposition efficiency of 94%. Cell viability was not affected after 2 h exposure to clean air in the ALI system. Cells exposed to AgNPs (0.45 and 0.74 μg cm–2) showed significantly (P < 0.05) reduced metabolic activities (64 and 46%, respectively). Our study shows that the ALI exposure system can be used for generating conditions that were more realistic for in vitro exposures, which enables improved mechanistic and toxicological studies of NPs in contact with human lung cells.Copyright © 2016 The
      Authors Journal of Applied Toxicology Published by John Wiley & Sons Ltd.
      PubDate: 2016-03-03T04:41:36.223457-05:
      DOI: 10.1002/jat.3304
       
  • Let‐7a modulates particulate matter (≤ 2.5 μm)‐induced oxidative
           stress and injury in human airway epithelial cells by targeting arginase 2
           
    • Authors: Lei Song; Dan Li, Yue Gu, Xiaoping Li, Liping Peng
      First page: 1302
      Abstract: Epidemiological studies show that particulate matter (PM) with an aerodynamic diameter ≤ 2.5 μm (PM2.5) is associated with cardiorespiratory diseases via the induction of excessive oxidative stress. However, the precise mechanism underlying PM2.5‐mediated oxidative stress injury has not been fully elucidated. Accumulating evidence has indicated the microRNA let‐7 family might play a role in PM‐mediated pathological processes. In this study, we investigated the role of let‐7a in oxidative stress and cell injury in human bronchial epithelial BEAS2B (B2B) cells after PM2.5 exposure. The let‐7a level was the most significantly decreased in B2B cells after PM2.5 exposure. The overexpression of let‐7a suppressed intracellular reactive oxygen species levels and the percentage of apoptotic cells after PM2.5 exposure, while the let‐7a level decreased arginase 2 (ARG2) mRNA and protein levels in B2B cells by directly targeting the ARG2 3′‐untranslated region. ARG2 expression was upregulated in B2B cells during PM2.5 treatment, and ARG2 knockdown could remarkably reduce oxidative stress and cellular injury. Moreover, its restoration could abrogate the protective effects of let‐7a against PM2.5‐induced injury. In conclusion, let‐7a decreases and ARG2 increases resulting from PM2.5 exposure may exacerbate oxidative stress, cell injury and apoptosis of B2B cells. The let‐7a/ARG2 axis is a likely therapeutic target for PM2.5‐induced airway epithelial injury. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-03-15T05:50:53.102023-05:
      DOI: 10.1002/jat.3309
       
  • Silver nanoparticles induce pro‐inflammatory gene expression and
           inflammasome activation in human monocytes
    • Authors: A. Murphy; A. Casey, G. Byrne, G. Chambers, O. Howe
      First page: 1311
      Abstract: A complete cytotoxic profile of exposure to silver (AgNP) nanoparticles investigating their biological effects on the innate immune response of circulating white blood cells is required to form a complete understanding of the risk posed. This was explored by measuring AgNP‐stimulated gene expression of the pro‐inflammatory cytokines interleukin‐1 (IL‐1), interleukin‐6 (IL‐6) and tumour necrosis factor‐alpha (TNF‐α) in THP‐1 monocytes. A further study, on human monocytes extracted from a cohort of blood samples, was carried out to compare with the AgNP immune response in THP‐1 cells along with the detection of pro‐IL‐1β which is a key mediator of the inflammasome complex.The aims of the study were to clearly demonstrate that AgNP can significantly up‐regulate pro‐inflammatory cytokine gene expression of IL‐1, IL‐6 and TNF‐α in both THP‐1 cells and primary blood monocytes thus indicating a rapid response to AgNP in circulation. Furthermore, a role for the inflammasome in AgNP response was indicated by pro‐IL‐1β cleavage and release. These results highlight the potential inflammatory effects of AgNP exposure and the responses evoked should be considered with respect to the potential harm that exposure may cause. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-03-10T05:13:09.077377-05:
      DOI: 10.1002/jat.3315
       
  • Investigation on the mechanism of non‐photocatalytically TiO2‐induced
           
    • Authors: Nirmal Kumar Gali; Zhi Ning, Walid Daoud, Peter Brimblecombe
      First page: 1355
      Abstract: Titanium dioxide (TiO2) nanoparticles are widely used in daily human life, and were reported to elicit biological effects such as oxidative stress either generating reactive oxygen species (ROS) or causing cell necrosis without generating ROS, whose underlying molecular mechanisms are not yet known. In this study, the role of dissolved oxygen in TiO2 catalytic activity in dark environment, and long‐term cytotoxic effects of TiO2 exposure were investigated. To determine the effect of dissolved oxygen, the anatase‐TiO2 nanoparticle suspension was prepared both in deoxygenated and regular MilliQ water, and a ~ 9‐fold higher ROS in regular MilliQ samples was observed compared to deoxygenated samples while in the dark, which suggested dissolved oxygen as the driving agent behind the TiO2 catalytic reaction. On the other hand, the differential cell viability and endogenous ROS activity was demonstrated through a sensitive macrophage‐based assay, on a dose‐ and time‐dependent manner. Both the cell number and endogenous ROS activity increased with increase in time till 48 h, followed by a reduction at 72 h exposure period. Long‐term exposures to these nanoparticles even at low concentrations were found detrimental to cells, where late apoptosis until 48 h and necrosis at 72 h leading to cell death were noted. Late apoptotic events and cell membrane cytoskeletal actin rearrangement observed were hypothesized to be induced by particle‐mediated cellular ROS. This in addition to radical generation ability of TiO2 in the dark will help further in better understanding of the toxicity mechanism in cells beyond ROS generation. Copyright © 2016 John Wiley & Sons, Ltd.
      PubDate: 2016-05-18T07:13:13.067956-05:
      DOI: 10.1002/jat.3341
       
  • Cytotoxic and inflammatory responses of TiO2 nanoparticles on human
           peripheral blood mononuclear cells
    • Authors: Supunsa Kongseng; Krongtong Yoovathaworn, Kanokpan Wongprasert, Rodjana Chunhabundit, Patinya Sukwong, Dakrong Pissuwan
      First page: 1364
      Abstract: Titanium dioxide nanoparticles (TiO2‐NPs) have been widely used in many applications. Owing to their nanoscale size, interactions between cells and NPs have been expansively investigated. With the health concerns raised regarding the adverse effects of these interactions, closer examination of whether TiO2‐NPs can induce toxicity towards human cells is greatly needed. Therefore, in this study, we investigated the cytotoxicity of TiO2‐NPs towards human blood cells (peripheral blood mononuclear cells [PBMCs]) in serum‐free medium, for which there is little information regarding the cytotoxic effects of TiO2‐NPs. Our results provide evidence that PBMCs treated with TiO2‐NPs (at concentrations ≥25 μg ml−1) for 24 h significantly reduced cell viability and significantly increased production of toxic mediators such as reactive oxygen species and inflammatory response cytokines such as interleukin‐6 and tumor necrosis factor‐α (P 
      PubDate: 2016-05-25T23:01:11.35977-05:0
      DOI: 10.1002/jat.3342
       
 
 
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