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Publisher: Springer-Verlag (Total: 2351 journals)

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Showing 1 - 200 of 2351 Journals sorted alphabetically
3D Printing in Medicine     Open Access   (Followers: 2)
3D Research     Hybrid Journal   (Followers: 21, SJR: 0.222, CiteScore: 1)
4OR: A Quarterly J. of Operations Research     Hybrid Journal   (Followers: 10, SJR: 0.825, CiteScore: 1)
AAPS J.     Hybrid Journal   (Followers: 26, SJR: 1.118, CiteScore: 4)
AAPS PharmSciTech     Hybrid Journal   (Followers: 8, SJR: 0.752, CiteScore: 3)
Abdominal Radiology     Hybrid Journal   (Followers: 17, SJR: 0.866, CiteScore: 2)
Abhandlungen aus dem Mathematischen Seminar der Universitat Hamburg     Hybrid Journal   (Followers: 4, SJR: 0.439, CiteScore: 0)
Academic Psychiatry     Full-text available via subscription   (Followers: 29, SJR: 0.53, CiteScore: 1)
Academic Questions     Hybrid Journal   (Followers: 8, SJR: 0.106, CiteScore: 0)
Accreditation and Quality Assurance: J. for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 31, SJR: 0.316, CiteScore: 1)
Acoustical Physics     Hybrid Journal   (Followers: 11, SJR: 0.359, CiteScore: 1)
Acoustics Australia     Hybrid Journal   (SJR: 0.232, CiteScore: 1)
Acta Analytica     Hybrid Journal   (Followers: 7, SJR: 0.367, CiteScore: 0)
Acta Applicandae Mathematicae     Hybrid Journal   (Followers: 1, SJR: 0.675, CiteScore: 1)
Acta Biotheoretica     Hybrid Journal   (Followers: 4, SJR: 0.284, CiteScore: 1)
Acta Diabetologica     Hybrid Journal   (Followers: 19, SJR: 1.587, CiteScore: 3)
Acta Endoscopica     Hybrid Journal   (Followers: 1)
acta ethologica     Hybrid Journal   (Followers: 4, SJR: 0.769, CiteScore: 1)
Acta Geochimica     Hybrid Journal   (Followers: 7, SJR: 0.24, CiteScore: 1)
Acta Geodaetica et Geophysica     Hybrid Journal   (Followers: 3, SJR: 0.305, CiteScore: 1)
Acta Geophysica     Hybrid Journal   (Followers: 11, SJR: 0.312, CiteScore: 1)
Acta Geotechnica     Hybrid Journal   (Followers: 7, SJR: 1.588, CiteScore: 3)
Acta Informatica     Hybrid Journal   (Followers: 5, SJR: 0.517, CiteScore: 1)
Acta Mathematica     Hybrid Journal   (Followers: 13, SJR: 7.066, CiteScore: 3)
Acta Mathematica Hungarica     Hybrid Journal   (Followers: 2, SJR: 0.452, CiteScore: 1)
Acta Mathematica Sinica, English Series     Hybrid Journal   (Followers: 6, SJR: 0.379, CiteScore: 1)
Acta Mathematica Vietnamica     Hybrid Journal   (SJR: 0.27, CiteScore: 0)
Acta Mathematicae Applicatae Sinica, English Series     Hybrid Journal   (SJR: 0.208, CiteScore: 0)
Acta Mechanica     Hybrid Journal   (Followers: 21, SJR: 1.04, CiteScore: 2)
Acta Mechanica Sinica     Hybrid Journal   (Followers: 5, SJR: 0.607, CiteScore: 2)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 7, SJR: 0.576, CiteScore: 2)
Acta Meteorologica Sinica     Hybrid Journal   (Followers: 3, SJR: 0.638, CiteScore: 1)
Acta Neurochirurgica     Hybrid Journal   (Followers: 7, SJR: 0.822, CiteScore: 2)
Acta Neurologica Belgica     Hybrid Journal   (Followers: 2, SJR: 0.376, CiteScore: 1)
Acta Neuropathologica     Hybrid Journal   (Followers: 4, SJR: 7.589, CiteScore: 12)
Acta Oceanologica Sinica     Hybrid Journal   (Followers: 3, SJR: 0.334, CiteScore: 1)
Acta Physiologiae Plantarum     Hybrid Journal   (Followers: 3, SJR: 0.574, CiteScore: 2)
Acta Politica     Hybrid Journal   (Followers: 18, SJR: 0.605, CiteScore: 1)
Activitas Nervosa Superior     Hybrid Journal   (SJR: 0.147, CiteScore: 0)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 8, SJR: 0.103, CiteScore: 0)
ADHD Attention Deficit and Hyperactivity Disorders     Hybrid Journal   (Followers: 25, SJR: 0.72, CiteScore: 2)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 9)
Administration and Policy in Mental Health and Mental Health Services Research     Partially Free   (Followers: 18, SJR: 1.005, CiteScore: 2)
Adsorption     Hybrid Journal   (Followers: 5, SJR: 0.703, CiteScore: 2)
Advances in Applied Clifford Algebras     Hybrid Journal   (Followers: 4, SJR: 0.698, CiteScore: 1)
Advances in Atmospheric Sciences     Hybrid Journal   (Followers: 37, SJR: 0.956, CiteScore: 2)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 20, SJR: 0.812, CiteScore: 1)
Advances in Contraception     Hybrid Journal   (Followers: 3)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 58, SJR: 1.09, CiteScore: 1)
Advances in Gerontology     Partially Free   (Followers: 8, SJR: 0.144, CiteScore: 0)
Advances in Health Sciences Education     Hybrid Journal   (Followers: 32, SJR: 1.64, CiteScore: 2)
Advances in Manufacturing     Hybrid Journal   (Followers: 3, SJR: 0.475, CiteScore: 2)
Advances in Polymer Science     Hybrid Journal   (Followers: 45, SJR: 1.04, CiteScore: 3)
Advances in Therapy     Hybrid Journal   (Followers: 5, SJR: 1.075, CiteScore: 3)
Aegean Review of the Law of the Sea and Maritime Law     Hybrid Journal   (Followers: 7)
Aequationes Mathematicae     Hybrid Journal   (Followers: 2, SJR: 0.517, CiteScore: 1)
Aerobiologia     Hybrid Journal   (Followers: 3, SJR: 0.673, CiteScore: 2)
Aesthetic Plastic Surgery     Hybrid Journal   (Followers: 11, SJR: 0.825, CiteScore: 1)
African Archaeological Review     Hybrid Journal   (Followers: 21, SJR: 0.862, CiteScore: 1)
Afrika Matematika     Hybrid Journal   (Followers: 1, SJR: 0.235, CiteScore: 0)
AGE     Hybrid Journal   (Followers: 7)
Ageing Intl.     Hybrid Journal   (Followers: 7, SJR: 0.39, CiteScore: 1)
Aggiornamenti CIO     Hybrid Journal   (Followers: 1)
Aging Clinical and Experimental Research     Hybrid Journal   (Followers: 3, SJR: 0.67, CiteScore: 2)
Agricultural Research     Hybrid Journal   (Followers: 6, SJR: 0.276, CiteScore: 1)
Agriculture and Human Values     Open Access   (Followers: 14, SJR: 1.173, CiteScore: 3)
Agroforestry Systems     Open Access   (Followers: 20, SJR: 0.663, CiteScore: 1)
Agronomy for Sustainable Development     Open Access   (Followers: 15, SJR: 1.864, CiteScore: 6)
AI & Society     Hybrid Journal   (Followers: 9, SJR: 0.227, CiteScore: 1)
AIDS and Behavior     Hybrid Journal   (Followers: 14, SJR: 1.792, CiteScore: 3)
Air Quality, Atmosphere & Health     Hybrid Journal   (Followers: 4, SJR: 0.862, CiteScore: 3)
Akupunktur & Aurikulomedizin     Full-text available via subscription   (Followers: 1)
Algebra and Logic     Hybrid Journal   (Followers: 6, SJR: 0.531, CiteScore: 0)
Algebra Universalis     Hybrid Journal   (Followers: 2, SJR: 0.583, CiteScore: 1)
Algebras and Representation Theory     Hybrid Journal   (Followers: 1, SJR: 1.095, CiteScore: 1)
Algorithmica     Hybrid Journal   (Followers: 9, SJR: 0.56, CiteScore: 1)
Allergo J.     Full-text available via subscription   (Followers: 1, SJR: 0.234, CiteScore: 0)
Allergo J. Intl.     Hybrid Journal   (Followers: 2)
Alpine Botany     Hybrid Journal   (Followers: 5, SJR: 1.11, CiteScore: 3)
ALTEX : Alternatives to Animal Experimentation     Open Access   (Followers: 3)
AMBIO     Hybrid Journal   (Followers: 10, SJR: 1.569, CiteScore: 4)
American J. of Cardiovascular Drugs     Hybrid Journal   (Followers: 16, SJR: 0.951, CiteScore: 3)
American J. of Community Psychology     Hybrid Journal   (Followers: 29, SJR: 1.329, CiteScore: 2)
American J. of Criminal Justice     Hybrid Journal   (Followers: 9, SJR: 0.772, CiteScore: 1)
American J. of Cultural Sociology     Hybrid Journal   (Followers: 18, SJR: 0.46, CiteScore: 1)
American J. of Dance Therapy     Hybrid Journal   (Followers: 5, SJR: 0.181, CiteScore: 0)
American J. of Potato Research     Hybrid Journal   (Followers: 2, SJR: 0.611, CiteScore: 1)
American J. of Psychoanalysis     Hybrid Journal   (Followers: 22, SJR: 0.314, CiteScore: 0)
American Sociologist     Hybrid Journal   (Followers: 16, SJR: 0.35, CiteScore: 0)
Amino Acids     Hybrid Journal   (Followers: 8, SJR: 1.135, CiteScore: 3)
AMS Review     Partially Free   (Followers: 4)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 7, SJR: 0.211, CiteScore: 1)
Analysis and Mathematical Physics     Hybrid Journal   (Followers: 6, SJR: 0.536, CiteScore: 1)
Analysis in Theory and Applications     Hybrid Journal   (Followers: 1)
Analysis of Verbal Behavior     Hybrid Journal   (Followers: 6)
Analytical and Bioanalytical Chemistry     Hybrid Journal   (Followers: 32, SJR: 0.978, CiteScore: 3)
Anatomical Science Intl.     Hybrid Journal   (Followers: 3, SJR: 0.367, CiteScore: 1)
Angewandte Schmerztherapie und Palliativmedizin     Hybrid Journal  
Angiogenesis     Hybrid Journal   (Followers: 3, SJR: 2.177, CiteScore: 5)
Animal Cognition     Hybrid Journal   (Followers: 20, SJR: 1.389, CiteScore: 3)
Annales françaises de médecine d'urgence     Hybrid Journal   (Followers: 1, SJR: 0.192, CiteScore: 0)
Annales Henri Poincaré     Hybrid Journal   (Followers: 3, SJR: 1.097, CiteScore: 2)
Annales mathématiques du Québec     Hybrid Journal   (Followers: 4, SJR: 0.438, CiteScore: 0)
Annali dell'Universita di Ferrara     Hybrid Journal   (SJR: 0.429, CiteScore: 0)
Annali di Matematica Pura ed Applicata     Hybrid Journal   (Followers: 1, SJR: 1.197, CiteScore: 1)
Annals of Biomedical Engineering     Hybrid Journal   (Followers: 17, SJR: 1.042, CiteScore: 3)
Annals of Combinatorics     Hybrid Journal   (Followers: 4, SJR: 0.932, CiteScore: 1)
Annals of Data Science     Hybrid Journal   (Followers: 12)
Annals of Dyslexia     Hybrid Journal   (Followers: 10, SJR: 0.85, CiteScore: 2)
Annals of Finance     Hybrid Journal   (Followers: 34, SJR: 0.579, CiteScore: 1)
Annals of Forest Science     Hybrid Journal   (Followers: 7, SJR: 0.986, CiteScore: 2)
Annals of Global Analysis and Geometry     Hybrid Journal   (Followers: 1, SJR: 1.228, CiteScore: 1)
Annals of Hematology     Hybrid Journal   (Followers: 15, SJR: 1.043, CiteScore: 2)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 12, SJR: 0.413, CiteScore: 1)
Annals of Microbiology     Hybrid Journal   (Followers: 11, SJR: 0.479, CiteScore: 2)
Annals of Nuclear Medicine     Hybrid Journal   (Followers: 5, SJR: 0.687, CiteScore: 2)
Annals of Operations Research     Hybrid Journal   (Followers: 10, SJR: 0.943, CiteScore: 2)
Annals of Ophthalmology     Hybrid Journal   (Followers: 13)
Annals of Regional Science     Hybrid Journal   (Followers: 8, SJR: 0.614, CiteScore: 1)
Annals of Software Engineering     Hybrid Journal   (Followers: 13)
Annals of Solid and Structural Mechanics     Hybrid Journal   (Followers: 9, SJR: 0.239, CiteScore: 1)
Annals of Surgical Oncology     Hybrid Journal   (Followers: 15, SJR: 1.986, CiteScore: 4)
Annals of Telecommunications     Hybrid Journal   (Followers: 9, SJR: 0.223, CiteScore: 1)
Annals of the Institute of Statistical Mathematics     Hybrid Journal   (Followers: 1, SJR: 1.495, CiteScore: 1)
Antonie van Leeuwenhoek     Hybrid Journal   (Followers: 5, SJR: 0.834, CiteScore: 2)
Apidologie     Hybrid Journal   (Followers: 4, SJR: 1.22, CiteScore: 3)
APOPTOSIS     Hybrid Journal   (Followers: 9, SJR: 1.424, CiteScore: 4)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2, SJR: 0.294, CiteScore: 1)
Applications of Mathematics     Hybrid Journal   (Followers: 3, SJR: 0.602, CiteScore: 1)
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 44, SJR: 0.571, CiteScore: 2)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 18, SJR: 0.21, CiteScore: 1)
Applied Categorical Structures     Hybrid Journal   (Followers: 4, SJR: 0.49, CiteScore: 0)
Applied Composite Materials     Hybrid Journal   (Followers: 50, SJR: 0.58, CiteScore: 2)
Applied Entomology and Zoology     Partially Free   (Followers: 6, SJR: 0.422, CiteScore: 1)
Applied Geomatics     Hybrid Journal   (Followers: 3, SJR: 0.733, CiteScore: 3)
Applied Geophysics     Hybrid Journal   (Followers: 9, SJR: 0.488, CiteScore: 1)
Applied Intelligence     Hybrid Journal   (Followers: 15, SJR: 0.6, CiteScore: 2)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4, SJR: 0.319, CiteScore: 1)
Applied Mathematics & Optimization     Hybrid Journal   (Followers: 9, SJR: 0.886, CiteScore: 1)
Applied Mathematics - A J. of Chinese Universities     Hybrid Journal   (Followers: 1, SJR: 0.17, CiteScore: 0)
Applied Mathematics and Mechanics     Hybrid Journal   (Followers: 5, SJR: 0.461, CiteScore: 1)
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 66, SJR: 1.182, CiteScore: 4)
Applied Physics A     Hybrid Journal   (Followers: 10, SJR: 0.481, CiteScore: 2)
Applied Physics B: Lasers and Optics     Hybrid Journal   (Followers: 25, SJR: 0.74, CiteScore: 2)
Applied Psychophysiology and Biofeedback     Hybrid Journal   (Followers: 8, SJR: 0.519, CiteScore: 2)
Applied Research in Quality of Life     Hybrid Journal   (Followers: 12, SJR: 0.316, CiteScore: 1)
Applied Solar Energy     Hybrid Journal   (Followers: 22, SJR: 0.225, CiteScore: 0)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 7, SJR: 0.542, CiteScore: 1)
Aquaculture Intl.     Hybrid Journal   (Followers: 26, SJR: 0.591, CiteScore: 2)
Aquarium Sciences and Conservation     Hybrid Journal   (Followers: 2)
Aquatic Ecology     Hybrid Journal   (Followers: 37, SJR: 0.656, CiteScore: 2)
Aquatic Geochemistry     Hybrid Journal   (Followers: 4, SJR: 0.591, CiteScore: 1)
Aquatic Sciences     Hybrid Journal   (Followers: 14, SJR: 1.109, CiteScore: 3)
Arabian J. for Science and Engineering     Hybrid Journal   (Followers: 5, SJR: 0.303, CiteScore: 1)
Arabian J. of Geosciences     Hybrid Journal   (Followers: 2, SJR: 0.319, CiteScore: 1)
Archaeological and Anthropological Sciences     Hybrid Journal   (Followers: 21, SJR: 1.052, CiteScore: 2)
Archaeologies     Hybrid Journal   (Followers: 12, SJR: 0.224, CiteScore: 0)
Archiv der Mathematik     Hybrid Journal   (Followers: 1, SJR: 0.725, CiteScore: 1)
Archival Science     Hybrid Journal   (Followers: 68, SJR: 0.745, CiteScore: 2)
Archive for History of Exact Sciences     Hybrid Journal   (Followers: 7, SJR: 0.186, CiteScore: 1)
Archive for Mathematical Logic     Hybrid Journal   (Followers: 3, SJR: 0.909, CiteScore: 1)
Archive for Rational Mechanics and Analysis     Hybrid Journal   (SJR: 3.93, CiteScore: 3)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 6, SJR: 0.79, CiteScore: 2)
Archives and Museum Informatics     Hybrid Journal   (Followers: 159, SJR: 0.101, CiteScore: 0)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 6, SJR: 1.41, CiteScore: 5)
Archives of Dermatological Research     Hybrid Journal   (Followers: 7, SJR: 1.006, CiteScore: 2)
Archives of Environmental Contamination and Toxicology     Hybrid Journal   (Followers: 14, SJR: 0.773, CiteScore: 2)
Archives of Gynecology and Obstetrics     Hybrid Journal   (Followers: 17, SJR: 0.956, CiteScore: 2)
Archives of Microbiology     Hybrid Journal   (Followers: 9, SJR: 0.644, CiteScore: 2)
Archives of Orthopaedic and Trauma Surgery     Hybrid Journal   (Followers: 9, SJR: 1.146, CiteScore: 2)
Archives of Osteoporosis     Hybrid Journal   (Followers: 2, SJR: 0.71, CiteScore: 2)
Archives of Sexual Behavior     Hybrid Journal   (Followers: 10, SJR: 1.493, CiteScore: 3)
Archives of Toxicology     Hybrid Journal   (Followers: 17, SJR: 1.541, CiteScore: 5)
Archives of Virology     Hybrid Journal   (Followers: 5, SJR: 0.973, CiteScore: 2)
Archives of Women's Mental Health     Hybrid Journal   (Followers: 17, SJR: 1.274, CiteScore: 3)
Archivio di Ortopedia e Reumatologia     Hybrid Journal  
Archivum Immunologiae et Therapiae Experimentalis     Hybrid Journal   (Followers: 2, SJR: 0.946, CiteScore: 3)
ArgoSpine News & J.     Hybrid Journal  
Argumentation     Hybrid Journal   (Followers: 6, SJR: 0.349, CiteScore: 1)
Arid Ecosystems     Hybrid Journal   (Followers: 2, SJR: 0.2, CiteScore: 0)
Arkiv för Matematik     Hybrid Journal   (Followers: 2, SJR: 0.766, CiteScore: 1)
Arnold Mathematical J.     Hybrid Journal   (Followers: 1, SJR: 0.355, CiteScore: 0)
Arthropod-Plant Interactions     Hybrid Journal   (Followers: 2, SJR: 0.839, CiteScore: 2)
Arthroskopie     Hybrid Journal   (Followers: 1, SJR: 0.131, CiteScore: 0)
Artificial Intelligence and Law     Hybrid Journal   (Followers: 11, SJR: 0.937, CiteScore: 2)
Artificial Intelligence Review     Hybrid Journal   (Followers: 18, SJR: 0.833, CiteScore: 4)
Artificial Life and Robotics     Hybrid Journal   (Followers: 10, SJR: 0.226, CiteScore: 0)
Asia Europe J.     Hybrid Journal   (Followers: 4, SJR: 0.504, CiteScore: 1)
Asia Pacific Education Review     Hybrid Journal   (Followers: 12, SJR: 0.479, CiteScore: 1)
Asia Pacific J. of Management     Hybrid Journal   (Followers: 16, SJR: 1.185, CiteScore: 2)
Asia-Pacific Education Researcher     Hybrid Journal   (Followers: 13, SJR: 0.353, CiteScore: 1)
Asia-Pacific Financial Markets     Hybrid Journal   (Followers: 3, SJR: 0.187, CiteScore: 0)
Asia-Pacific J. of Atmospheric Sciences     Hybrid Journal   (Followers: 19, SJR: 0.855, CiteScore: 1)
Asian Business & Management     Hybrid Journal   (Followers: 9, SJR: 0.378, CiteScore: 1)
Asian J. of Business Ethics     Hybrid Journal   (Followers: 11)
Asian J. of Criminology     Hybrid Journal   (Followers: 6, SJR: 0.543, CiteScore: 1)
AStA Advances in Statistical Analysis     Hybrid Journal   (Followers: 4, SJR: 0.548, CiteScore: 1)
AStA Wirtschafts- und Sozialstatistisches Archiv     Hybrid Journal   (Followers: 5, SJR: 0.183, CiteScore: 0)
ästhetische dermatologie & kosmetologie     Full-text available via subscription  
Astronomy and Astrophysics Review     Hybrid Journal   (Followers: 22, SJR: 3.385, CiteScore: 5)

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Similar Journals
Journal Cover
Archives of Toxicology
Journal Prestige (SJR): 1.541
Citation Impact (citeScore): 5
Number of Followers: 17  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1432-0738 - ISSN (Online) 0340-5761
Published by Springer-Verlag Homepage  [2351 journals]
  • Dietary diisononylphthalate contamination induces hepatic stress: a
           multidisciplinary investigation in gilthead seabream ( Sparus aurata )
           liver
    • Abstract: In this study, adult gilthead seabream (Sparus aurata) were exposed for 21 days to Di-iso-nonylphthalte (DiNP at 15 and 1500 μg kg−1 bw day−1) via the diet. This plastic additive has been recently introduced to replace the di-(2-ethylhexyl)phthalate, the toxicity of which has been demonstrated conclusively both in vivo and in vitro trials. An analysis of a set of biomarkers involved in stress and immune response provides evidence of hepatic toxicity by DiNP in the present study. Both hsp70 and gr mRNA levels were upregulated significantly by DiNP, while plasma cortisol increased only in fish fed with the lowest DiNP dose. The oxidative stress markers g6pdh, glut red, gpx1 and CAT were upregulated by DiNP; gst mRNA was induced by the high dose and gck mRNA was downregulated significantly by the low dose. The mRNA levels of genes involved in the immune response, such as pla2, 5-lox, tnfa and cox2, were upregulated significantly only by the high dose of DiNP, while il1 mRNA increases in both doses. These molecular evidences were complemented with features obtained by Fourier Transform Infrared Imaging (FTIRI) analysis regarding the hepatic distribution of the main biological macromolecules. The FTIRI analysis showed an alteration of biochemical composition in DiNP samples. In particular, the low dose of DiNP induced an increase of saturated and unsaturated lipids and phosphorylated proteins, and a decrease of glycogen levels. The levels of caspase did not change significantly in the study, suggesting that DiNP does not activate apoptosis. Finally, the results also suggested the onset of hepatic oxidative stress and the activation of immune response, adding new knowledge to the already described hepatic DiNP toxicity.
      PubDate: 2019-06-22
       
  • Quantification of freely dissolved effect concentrations in in vitro
           cell-based bioassays
    • Abstract: Improved understanding of chemical exposure in in vitro bioassays is required for quantitative in vitro–in vivo extrapolation (QIVIVE). In this study, we quantified freely dissolved concentrations in medium sampled from in vitro cell-based bioassays (Cfree,medium) for nine chemicals with different hydrophobicity and speciation at the time point of dosing and after an incubation period of 24 h using solid-phase microextraction. The chemicals were tested in two reporter gene assays, the AREc32 assay indicative of the oxidative stress response and the PPARγ-GeneBLAzer assay that responds to chemicals which bind to the peroxisome proliferator-activated receptor gamma. For seven of the nine chemicals, Cfree,medium did not change significantly over time in both assays and the experimentally determined Cfree,medium generally agreed well with predictions of a mass balance model that describes the partitioning between proteinaceous and lipidous medium constituents, cells and the aqueous phase. Two chemicals showed a decrease of Cfree,medium in the AREc32 assay over time that was probably caused by cellular metabolism. Furthermore, Cfree,medium of the acidic chemical diclofenac deviated from the model predictions by more than a factor of 10 at higher concentrations, which indicates nonlinear binding and saturation of the medium proteins. Bioassay results are typically reported as nominal effect concentrations (ECnom), although it is established that freely dissolved effect concentrations (ECfree) are a better measure for the bioavailable dose and the method developed here provides a simple experimental approach to measure and model ECfree in in vitro bioassay for improved QIVIVE models.
      PubDate: 2019-06-22
       
  • Distribution of the (synthetic) cannabinoids JWH-210, RCS-4, as well as
           ∆9-tetrahydrocannabinol following pulmonary administration to pigs
    • Abstract: New psychoactive substances, especially synthetic cannabinoids (SC), are gaining increasing relevance in postmortem forensic toxicology. Particularly, the interpretation of analytical results is challenging, as usually, no toxicokinetic (TK) data concerning distribution in organs and tissues are available. Thus, a controlled pig TK study allowing for examination of organ and tissue distribution of SC was performed. For this purpose, 12 pigs received a single pulmonary dose of 200 µg/kg body weight each of 4-ethylnaphthalene-1-yl-(1-pentylindole-3-yl)methanone (JWH-210), 2-(4-methoxyphenyl)-1-(1-pentylindole-3-yl)methanone (RCS-4), and Δ9-tetrahydrocannabinol (THC) via an ultrasonic nebulizer. Eight hours after administration, the animals were put to death by the administration of T61. Thereupon, relevant organs, important body fluids such as bile and colon content, and tissues such as muscle tissue were collected. After enzymatic hydrolysis and solid-phase extraction, analysis was performed by liquid chromatography–tandem mass spectrometry. For quantification, a standard addition method was applied. The parent compounds could be detected in every analyzed specimen with the exception of colon content. Regarding JWH-210, the kidneys and lungs are viable matrices for postmortem analysis. In terms of RCS-4, the lungs were found to be an appropriate matrix. Concerning THC, the liver, bile fluid as well as duodenum content were suitable matrices for detection. Metabolites were only detected in tissues/body fluids involved in metabolism and/or elimination. Bile fluid and duodenum content were shown, as the most appropriate specimens for quantification of metabolites.
      PubDate: 2019-06-21
       
  • Intestinal and hepatic biotransformation of pyrrolizidine alkaloid N
           -oxides to toxic pyrrolizidine alkaloids
    • Abstract: Pyrrolizidine alkaloids (PAs) are among the most significant groups of phytotoxins present in more than 6000 plants in the world. Hepatotoxic retronecine-type PAs and their corresponding N-oxides usually co-exist in plants. Although PA-induced hepatotoxicity is known for a long time and has been extensively studied, the toxicity of PA N-oxide is rarely investigated. Recently, we reported PA N-oxide-induced hepatotoxicity in humans and rodents and also suggested the association of such toxicity with metabolic conversion of PA N-oxides to the corresponding toxic PAs. However, the detailed biochemical mechanism of PA N-oxide-induced hepatotoxicity is largely unknown. The present study investigated biotransformation of four representative cyclic retronecine-type PA N-oxides to their corresponding PAs in both gastrointestinal tract and liver. The results demonstrated that biotransformation of PA N-oxides to PAs was mediated by both intestinal microbiota and hepatic cytochrome P450 monooxygenases (CYPs), in particular CYP1A2 and CYP2D6. Subsequently, the formed PAs were metabolically activated predominantly by hepatic CYPs to form reactive metabolites exerting hepatotoxicity. Our findings delineated, for the first time, that the metabolism-mediated mechanism of PA N-oxide intoxication involved metabolic reduction of PA N-oxides to their corresponding PAs in both intestine and liver followed by oxidative bioactivation of the resultant PAs in the liver to generate reactive metabolites which interact with cellular proteins leading to hepatotoxicity. In addition, our results raised a public concern and also encouraged further investigations on potentially remarkable variations in PA N-oxide-induced hepatotoxicity caused by significantly altered intestinal microbiota due to individual differences in diets, life styles, and medications.
      PubDate: 2019-06-20
       
  • Validity of different biomonitoring parameters in human urine for the
           assessment of occupational exposure to naphthalene
    • Abstract: Up to date, information on the validity of human biomonitoring (HBM) parameters of naphthalene exposure is poor. This study was performed to reveal the relation between occupational exposure to naphthalene and biological exposure markers. Therefore, ten lowly and highly exposed workers from the abrasives industry were selected to characterise a broad exposure range. Naphthalene in air was determined by personal air monitoring during one shift. For biological monitoring, pre- and post-shift urine samples collected on 2 days of a working week were analysed for 1,2-dihydroxynaphthalene (1,2-DHN), 1- and 2-naphthol, 1- and 2-naphthylmercapturic acid (NMA). The naphthalene concentration in air was in the range of 0.5 to 11.6 mg/m3. The biomarkers in urine showed post-shift concentration in the range of 114–51,809 µg/L for 1,2-DHN, 0.8–666 µg/L for 1–NMA, 2–2698 µg/L for 1-naphthol and 4–1135 µg/L for 2-naphthol, respectively. 2-NMA was not detected. The urinary levels increased significantly from pre- to post-shift for all analysed parameters and an accumulation over the working week was observed. Significant positive correlations were observed between 1,2-DHN, 1-NMA, 1- and 2-naphthol in post-shift urine samples and personal exposure to naphthalene in the air. 1-NMA and 1,2-DHN, 1- and 2-naphthol have been demonstrated as suitable biomarkers for naphthalene exposure monitoring. Of the determined biomarkers, 1,2-DHN is by far the metabolite with the highest concentration in the urine samples.
      PubDate: 2019-06-20
       
  • Deciphering the uranium target proteins in human dopaminergic SH-SY5Y
           cells
    • Abstract: Uranium (U) is the heaviest naturally occurring element ubiquitously present in the Earth’s crust. Human exposure to low levels of U is, therefore, unavoidable. Recently, several studies have clearly pointed out that the brain is a sensitive target for U, but the mechanisms leading to the observed neurological alterations are not fully known. To deepen our knowledge of the biochemical disturbances resulting from U(VI) toxicity in neuronal cells, two complementary strategies were set up to identify the proteins that selectively bind U(VI) in human dopaminergic SH-SY5Y cells. The first strategy relies on the selective capture of proteins capable of binding U(VI), using immobilized metal affinity chromatography, and starting from lysates of cells grown in a U(VI)-free medium. The second strategy is based on the separation of U-enriched protein fractions by size-exclusion chromatography, starting from lysates of U(VI)-exposed cells. High-resolution mass spectrometry helped us to highlight 269 common proteins identified as the urano-proteome. They were further analyzed to characterize their cellular localization and biological functions. Four canonical pathways, related to the protein ubiquitination system, gluconeogenesis, glycolysis, and the actin cytoskeleton proteins, were particularly emphasized due to their high content of U(VI)-bound proteins. A semi-quantification was performed to concentrate on the ten most abundant proteins, whose physico-chemical characteristics were studied in particular depth. The selective interaction of U(VI) with these proteins is an initial element of proof of the possible metabolic effects of U(VI) on neuronal cells at the molecular level.
      PubDate: 2019-06-20
       
  • PON1 increases cellular DNA damage by lactone substrates
    • Abstract: Paraoxonase 1 (PON1) is a high-density lipoprotein (HDL)-associated enzyme that by hydrolysing exogenous and endogenous substrates can provide protection against substrate induced toxicity. To investigate the extent to which PON1 provides protection against lactone induced DNA damage, DNA damage was measured in HepG2 cells using the neutral Comet assay following lactone treatment in the presence and absence of exogenous recombinant PON1 (rPON1). Low dose lactones (10 mM) caused little or no damage while high doses (100 mM) induced DNA damage in the following order of potency: α-angelica lactone > γ-butyrolactone ~ γ-hexalactone > γ-heptalactone ~ γ-octaclactone ~ γ-furanone ~ γ-valerolactone > γ-decalactone. Co-incubation of 100 mM lactone with rPON1, resulted in almost all cells showing extensive DNA damage, particularly with those lactones that decreased rPON1 activity by > 25%. In contrast, with the lactones that are poor rPON1 subtrates (γ-decalactone and γ-furanone), rPON1 did not increase DNA damage. DNA damage induced by a 1 h co-treatment with 10 mM α-angelica lactone and rPON1 was reduced when cells when incubated for a further 4 h in fresh medium suggesting break formation was due to induced DNA damage rather than apoptosis. Preincubation (1–6 h) of α-angelica lactone with rPON1 in the absence of cells, decreased cellular DNA damage by around 40%  in comparison to cells treated without preincubation. These results suggest that in addition to its well-recognised detoxification effects, PON1 can increase genotoxicity potentially by hydrolysing certain lactones to reactive intermediates that increase DNA damage via the formation of DNA adducts.
      PubDate: 2019-06-17
       
  • Combined transcriptomic and proteomic analysis reveals a diversity of
           venom-related and toxin-like peptides expressed in the mat anemone
           Zoanthus natalensis (Cnidaria, Hexacorallia)
    • Abstract: Venoms from marine animals have been recognized as a new emerging source of peptide-based therapeutics. Several peptide toxins from sea anemone have been investigated as therapeutic leads or pharmacological tools. Venom complexity should be further highlighted using combined strategies of large-scale sequencing and data analysis which integrated transcriptomics and proteomics to elucidate new proteins or peptides to be compared among species. In this work, transcriptomic and proteomic analyses were combined to identify six groups of expressed peptide toxins in Zoanthus natalensis. These include neurotoxin, hemostatic and hemorrhagic toxin, protease inhibitor, mixed function enzymes, venom auxiliary proteins, allergen peptides, and peptides related to the innate immunity. Molecular docking analysis indicated that one expressed Zoanthus Kunitz-like peptide, ZoaKuz1, could be a voltage-gated potassium channels blocker and, hence, it was selected for functional studies. Functional bioassays revealed that ZoaKuz1 has an intrinsic neuroprotective activity in zebrafish model of Parkinson’s disease. Since pharmacological blockade of KV channels is known to induce neuroprotective effects, ZoaKuz1 holds the potential to be developed in a therapeutic tool to control neural dysfunction by slowing or even halting neurodegeneration mediated by ion-channel hyperactivity.
      PubDate: 2019-06-15
       
  • Bioactivation of the tobacco carcinogens 4-aminobiphenyl (4-ABP) and
           2-amino-9 H -pyrido[2,3- b ]indole (AαC) in human bladder RT4 cells
    • Abstract: Occupational and tobacco exposure to aromatic amines (AAs) including 4-aminobiphenyl (4-ABP) and 2-naphthylamine (2-NA) are associated with bladder cancer (BC) risk. Several epidemiological studies have also reported a possible role for structurally related heterocyclic aromatic amines (HAAs) formed in tobacco smoke or cooked meats with BC risk. We had screened for DNA adducts of 4-ABP, 2-NA, and several prominent HAAs formed in tobacco smoke or grilled meats including 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-3,8-dimethylmidazo[4,5-f]quinoxaline (MeIQx), and 2-amino-9H-pyrido[2,3-b]indole (AαC) in the bladder DNA of BC patients, using liquid chromatography/mass spectrometry. We detected DNA adducts of 4-ABP, but not adducts of the other carcinogens. In this study, we have examined the capacity of RT4 cells, an epithelial human bladder cell line, to bioactivate AAs and HAAs to DNA damaging agents, which may contribute to BC. 4-ABP and AαC formed DNA adducts, but DNA adducts of 2-NA, PhIP, and MeIQx were not detected. 4-ABP DNA adducts were formed at tenfold higher levels than AαC adducts. Pretreatment of RT4 cells with α-naphthoflavone (1–10 µM), a specific cytochrome P450 1 (CYP1) inhibitor, decreased AαC adduct formation by 50% but did not affect the level of 4-ABP adducts. However, cell pretreatment with 8-methoxypsoralen (0.1–1 µM), a potent inhibitor of CYP2A, resulted in a 90% decrease of 4-ABP DNA adducts levels. These data signify that CYP2A and CYP1A isoforms expressed in the target urothelium bioactivate 4-ABP and AαC, respectively, and may be a critical feature of aromatic amine-induced urinary bladder carcinogenesis. The bioactivation of other tobacco and environmental AAs by bladder CYPs and their ensuing bladder DNA damage warrants further study.
      PubDate: 2019-06-15
       
  • Development of a neurotoxicity assay that is tuned to detect mitochondrial
           toxicants
    • Abstract: Many neurotoxicants affect energy metabolism in man, but currently available test methods may still fail to predict mito- and neurotoxicity. We addressed this issue using LUHMES cells, i.e., human neuronal precursors that easily differentiate into mature neurons. Within the NeuriTox assay, they have been used to screen for neurotoxicants. Our new approach is based on culturing the cells in either glucose or galactose (Glc–Gal–NeuriTox) as the main carbohydrate source during toxicity testing. Using this Glc–Gal–NeuriTox assay, 52 mitochondrial and non-mitochondrial toxicants were tested. The panel of chemicals comprised 11 inhibitors of mitochondrial respiratory chain complex I (cI), 4 inhibitors of cII, 8 of cIII, and 2 of cIV; 8 toxicants were included as they are assumed to be mitochondrial uncouplers. In galactose, cells became more dependent on mitochondrial function, which made them 2–3 orders of magnitude more sensitive to various mitotoxicants. Moreover, galactose enhanced the specific neurotoxicity (destruction of neurites) compared to a general cytotoxicity (plasma membrane lysis) of the toxicants. The Glc–Gal–NeuriTox assay worked particularly well for inhibitors of cI and cIII, while the toxicity of uncouplers and non-mitochondrial toxicants did not differ significantly upon glucose ↔ galactose exchange. As a secondary assay, we developed a method to quantify the inhibition of all mitochondrial respiratory chain functions/complexes in LUHMES cells. The combination of the Glc–Gal–NeuriTox neurotoxicity screening assay with the mechanistic follow up of target site identification allowed both, a more sensitive detection of neurotoxicants and a sharper definition of the mode of action of mitochondrial toxicants.
      PubDate: 2019-06-12
       
  • Correction to: A high-cholesterol diet promotes steatohepatitis and liver
           tumorigenesis in HCV core gene transgenic mice
    • Abstract: In the original publication of the article.
      PubDate: 2019-06-08
       
  • Verification of soman-related nerve agents via detection of phosphonylated
           adducts from rabbit albumin in vitro and in vivo
    • Abstract: A major challenge in organophosphate compound (OP) and OP nerve agent (OPNA) research has been in the identification and utilization of reliable biomarkers for rapid, sensitive, and efficient detection of OP exposure. Albumin has been widely studied as a biomarker for retrospective verification of exposure to OPNAs, including soman (GD), by detecting the phosphonylation of specific amino acid residues. The aim of the present study was to identify binding sites between GD and rabbit serum albumin in vitro and in vivo. A nano-liquid chromatography coupled with a quadrupole-orbitrap mass spectrometry (nLC-Q-Orbitrap-MS) was used to examine the GD-modified adducts of rabbit albumin. A total of 11 GD-modified sites were found in rabbit serum albumin across three experimental models. The following five GD-modified rabbit albumin sites, which were all lysine residues, were established in vivo: K188, K329, K162, K233, and K525. Two of these five lysine residues, K188 in peptide EK*ALISAAQER and K162 in peptide YK*AILTECCEAADK, were stable for at least 7 days in vivo. Molecular simulation of the GD–albumin interaction provided theoretical evidence for reactivity of the identified lysine residues. The findings suggest that these modifiable lysine residues are potential biomarkers of GD exposure for retrospective analysis by Q-Orbitrap-MS.
      PubDate: 2019-06-03
       
  • Comment on ‘Kim, S.-J., Choi, E.-J., Choi, G.-W., Lee, Y.-B., and Cho,
           H.-Y. (2019). Exploring sex differences in human health risk assessment
           for PFNA and PFDA using a PBPK model, Arch Toxicol 93:311–330’
    • PubDate: 2019-05-29
       
  • Uptake and effects of orally ingested polystyrene microplastic particles
           in vitro and in vivo
    • Abstract: Evidence exists that humans are exposed to plastic microparticles via diet. Data on intestinal particle uptake and health-related effects resulting from microplastic exposure are scarce. Aim of the study was to analyze the uptake and effects of microplastic particles in human in vitro systems and in rodents in vivo. The gastrointestinal uptake of microplastics was studied in vitro using the human intestinal epithelial cell line Caco-2 and thereof-derived co-cultures mimicking intestinal M-cells and goblet cells. Different sizes of spherical fluorescent polystyrene (PS) particles (1, 4 and 10 µm) were used to study particle uptake and transport. A 28-days in vivo feeding study was conducted to analyze transport at the intestinal epithelium and oxidative stress response as a potential consequence of microplastic exposure. Male reporter gene mice were treated three times per week by oral gavage with a mixture of 1 µm (4.55 × 107 particles), 4 µm (4.55 × 107 particles) and 10 µm (1.49 × 106 particles) microplastics at a volume of 10 mL/kg/bw. Effects of particles on macrophage polarization were investigated using the human cell line THP-1 to detect a possible impact on intestinal immune cells. Altogether, the results of the study demonstrate the cellular uptake of a minor fraction of particles. In vivo data show the absence of histologically detectable lesions and inflammatory responses. The particles did not interfere with the differentiation and activation of the human macrophage model. The present results suggest that oral exposure to PS microplastic particles under the chosen experimental conditions does not pose relevant acute health risks to mammals.
      PubDate: 2019-05-28
       
  • Proteomic analysis of hippocampal proteins in acrylamide-exposed Wistar
           rats
    • Abstract: Acrylamide has been used industrially and also found in certain foods cooked at high temperatures. Previous reports described acrylamide-related human intoxication who presented with ataxia, memory impairment, and/or illusion. The aim of this study was to characterize the molecular mechanisms of neurotoxicity of acrylamide by analyzing the expression levels of various proteins in the hippocampus of rats exposed to acrylamide. Male Wistar rats were administered acrylamide by gavage at 0, 2, and 20 mg/kg for 1 week or 0, 0.2, 2, and 20 mg/kg for 5 weeks. At the end of the experiment, the hippocampus was dissected out and proteins were extracted for two-dimensional difference gel electrophoresis combined with matrix-assisted laser-desorption ionization time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF/MS). MALDI-TOF/TOF/MS identified significant changes in two proteins in the 1-week and 22 proteins in the 5-week exposure groups. These changes were up-regulation in 9 and down-regulation in 13 proteins in the hippocampus of rats exposed to acrylamide at 20 mg/kg for 5 weeks. PANTHER overrepresentation test based on the GO of biological process showed significant overrepresentation in proteins annotated to nicotinamide nucleotide metabolic process, coenzyme biosynthetic process, pyruvate metabolic process, and carbohydrate metabolic process. The test also showed significant overrepresentation in proteins annotated to creatinine kinase activity for the GO of molecular function as well as myelin sheath, cytoplasmic part, and cell body for the GO of cellular component. Comparison with a previous proteomic study on hippocampal proteins in rats exposed to 1-bromopropane identified triosephosphate isomerase, mitochondrial creatine kinase U-type, creatine kinase β-type and proteasome subunit α type-1 as proteins affected by exposure to acrylamide and 1-bromopropane, suggesting a common mechanism of neurotoxicity for soft electrophiles.
      PubDate: 2019-05-23
       
  • Ecdysteroids as non-conventional anabolic agent: performance enhancement
           by ecdysterone supplementation in humans
    • Abstract: Recent studies suggest that the anabolic effect of ecdysterone, a naturally occurring steroid hormone claimed to enhance physical performance, is mediated by estrogen receptor (ER) binding. In comparison with the prohibited anabolic agents (e.g., metandienone and others), ecdysterone revealed to be even more effective in a recent study performed in rats. However, scientific studies in humans are very rarely accessible. Thus, our project aimed at investigating the effects of ecdysterone-containing products on human sport exercise. A 10-week intervention study of strength training of young men (n = 46) was carried out. Different doses of ecdysterone-containing supplements have been administered during the study to evaluate the performance-enhancing effect. Analysis of blood and urine samples for ecdysterone and potential biomarkers of performance enhancement has been conducted. To ensure the specificity of the effects measured, a comprehensive screening for prohibited performance-enhancing substances was also carried out. Furthermore, the administered supplement has been tested for the absence of anabolic steroid contaminations prior to administration. Significantly higher increases in muscle mass were observed in those participants that were dosed with ecdysterone. The same hypertrophic effects were also detected in vitro in C2C12 myotubes. Even more relevant with respect to sports performance, significantly more pronounced increases in one-repetition bench press performance were observed. No increase in biomarkers for liver or kidney toxicity was noticed. These data underline the effectivity of an ecdysterone supplementation with respect to sports performance. Our results strongly suggest the inclusion of ecdysterone in the list of prohibited substances and methods in sports in class S1.2 “other anabolic agents”.
      PubDate: 2019-05-23
       
  • Neurotoxicity of Micrurus lemniscatus lemniscatus (South American
           coralsnake) venom in vertebrate neuromuscular preparations in vitro and
           neutralization by antivenom
    • Abstract: We investigated the effect of South American coralsnake (Micrurus lemniscatus lemniscatus) venom on neurotransmission in vertebrate nerve–muscle preparations in vitro. The venom (0.1–30 µg/ml) showed calcium-dependent PLA2 activity and caused irreversible neuromuscular blockade in chick biventer cervicis (BC) and mouse phrenic nerve–diaphragm (PND) preparations. In BC preparations, contractures to exogenous acetylcholine and carbachol (CCh), but not KCl, were abolished by venom concentrations ≥ 0.3 µg/ml; in PND preparations, the amplitude of the tetanic response was progressively attenuated, but with little tetanic fade. In low Ca2+ physiological solution, venom (10 µg/ml) caused neuromuscular blockade in PND preparations within ~ 10 min that was reversible by washing; the addition of Ca2+ immediately after the blockade temporarily restored the twitch responses, but did not prevent the progression to irreversible blockade. Venom (10 µg/ml) did not depolarize diaphragm muscle, prevent depolarization by CCh, or cause muscle contracture or histological damage. Venom (3 µg/ml) had a biphasic effect on the frequency of miniature end-plate potentials, but did not affect their amplitude; there was a progressive decrease in the amplitude of evoked end-plate potentials. The amplitude of compound action potentials in mouse sciatic nerve was unaffected by venom (10 µg/ml). Pre-incubation of venom with coralsnake antivenom (Instituto Butantan) at the recommended antivenom:venom ratio did not neutralize the neuromuscular blockade in PND preparations, but total neutralization was achieved with a tenfold greater volume of antivenom. The addition of antivenom after 50% and 80% blockade restored the twitch responses. These results show that M. lemniscatus lemniscatus venom causes potent, irreversible neuromuscular blockade, without myonecrosis. This blockade is apparently mediated by pre- and postsynaptic neurotoxins and can be reversed by coralsnake antivenom.
      PubDate: 2019-05-23
       
  • The in vivo developmental toxicity of diethylstilbestrol (DES) in rat
           evaluated by an alternative testing strategy
    • Abstract: In the present study, we evaluated an alternative testing strategy to quantitatively predict the in vivo developmental toxicity of the synthetic hormone diethylstilbestrol (DES). To this end, a physiologically based kinetic (PBK) model was defined that was subsequently used to translate concentration–response data for the in vitro developmental toxicity of DES, obtained in the ES-D3 cell differentiation assay, into predicted in vivo dose–response data for developmental toxicity. The previous studies showed that the PBK model-facilitated reverse dosimetry approach is a useful approach to quantitatively predict the developmental toxicity of several developmental toxins. The results obtained in the present study show that the PBK model adequately predicted DES blood concentrations in rats. Further studies revealed that DES tested positive in the ES-D3 differentiation assay and that DES-induced inhibition of the ES-D3 cell differentiation could be counteracted by the estrogen receptor alpha (ERα) antagonist fulvestrant, indicating that the in vitro ES-D3 cell differentiation assay was able to mimic the role of ERα reported in the mode of action underlying the developmental toxicity of DES in vivo. In spite of this, combining these in vitro data with the PBK model did not adequately predict the in vivo developmental toxicity of DES in a quantitative way. It is concluded that although the EST qualifies DES as a developmental toxin and detects the role of ERα in this process, the ES-D3 cell differentiation assay of the EST apparently does not adequately capture the processes underlying DES-induced developmental toxicity in vivo.
      PubDate: 2019-05-22
       
  • Novel insight in estrogen homeostasis and bioactivity in the ACI rat model
           of estrogen-induced mammary gland carcinogenesis
    • Abstract: Despite being widely used to investigate 17β-estradiol (E2)-induced mammary gland (MG) carcinogenesis and prevention thereof, estrogen homeostasis and its significance in the female August Copenhagen Irish (ACI) rat model is unknown. Thus, levels of 12 estrogens including metabolites and conjugates were determined mass spectrometrically in 38 plasmas and 52 tissues exhibiting phenotypes ranging from normal to palpable tumor derived from a representative ACI study using two different diets. In tissues, 40 transcripts encoding proteins involved in estrogen (biotrans)formation, ESR1-mediated signaling, proliferation and oxidative stress were analyzed (TaqMan PCR). Influence of histo(patho)logic phenotypes and diet on estrogen and transcript levels was analyzed by 2-way ANOVA and explanatory variables influencing levels and bioactivity of estrogens in tissues were identified by multiple linear regression models. Estrogen profiles in tissue and plasma and the influence of Hsd17b1 levels on intra-tissue levels of E2 and E1 conclusively indicated intra-mammary formation of E2 in ACI tumors by HSD17B1-mediated conversion of E1. Proliferation in ACI tumors was influenced by Egfr, Igf1r, Hgf and Met levels. 2-MeO-E1, the only oxidative estrogen metabolite detected above 28–42 fmol/g, was predominately observed in hyperplastic tissues and intra-tissue conversion of E1 seemed to contribute to its levels. The association of the occurrence of 2-MeO-E1 with higher levels of oxidative stress observed in hyperplastic and tumor tissues remained equivocal. Thus, the present study provides mechanistic explanation for previous and future results observed in the ACI model.
      PubDate: 2019-05-22
       
  • Okadaic acid activates Wnt/β-catenin-signaling in human HepaRG cells
    • Abstract: The lipophilic phycotoxin okadaic acid (OA) occurs in the fatty tissue and hepatopancreas of filter-feeding shellfish. The compound provokes the diarrhetic shellfish poisoning (DSP) syndrome after intake of seafood contaminated with high levels of the DSP toxin. In animal experiments, long-term exposure to OA is associated with an elevated risk for tumor formation in different organs including the liver. Although OA is a known inhibitor of the serine/threonine protein phosphatase 2A, the mechanisms behind OA-induced carcinogenesis are not fully understood. Here, we investigated the influence of OA on the β-catenin-dependent Wnt-signaling pathway, addressing a major oncogenic pathway relevant for tumor development. We analyzed OA-mediated effects on β-catenin and its biological function, cellular localization, post-translational modifications, and target gene expression in human HepaRG hepatocarcinoma cells treated with non-cytotoxic concentrations up to 50 nM. We detected concentration- and time-dependent effects of OA on the phosphorylation state, cellular redistribution as well as on the amount of transcriptionally active β-catenin. These findings were confirmed by quantitative live-cell imaging of U2OS cells stably expressing a green fluorescent chromobody which specifically recognize hypophosphorylated β-catenin. Finally, we demonstrated that nuclear translocation of β-catenin mediated by non-cytotoxic OA concentrations results in an upregulation of Wnt-target genes. In conclusion, our results show a significant induction of the canonical Wnt/β-catenin-signaling pathway by OA in human liver cells. Our data contribute to a better understanding of the molecular mechanisms underlying OA-induced carcinogenesis.
      PubDate: 2019-05-21
       
 
 
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