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158 SECTION | I General




  VetBooks.ir  it is possible to eliminate compounds that exhibit high  will therefore be to continue monitoring and improving
                                                                the welfare of animals used in toxicity testing and to
             levels of basal toxicity in several cell types and reduce
                                                                advise on issues relating to the development of in vitro
             unnecessary suffering in animals. In both in vitro and
             in vivo testing it is important to use a battery of appropri-  alternatives.
             ate endpoint measurements of both basal toxicity and cell/
             tissue-specific toxicity at each level, in order to increase
             the reliability and predictive potential of the data
             produced.                                          REFERENCES
                In vitro toxicology has made significant advances in  Arnold, D.L., Grice, H.C., Krewski, D.R., 1990. Handbook of In Vivo
             the last few decades, by improving and finding solutions  Toxicity Testing. Academic Press, San Diego, CA.
             to its limitations. For example, cell culture systems are  Auletta, C.S., 2004. Current in vivo assays for cutaneous toxicity: local
             now being designed to be metabolically competent and  and systemic toxicity testing. Pharmacol. Toxicol. 95, 201 208.
             viable for several weeks, making them appropriate not  Barlow, S.M., Greig, J.B., Bridges, J.W., et al., 2002. Hazard identifica-
             only for short- but also for long-term toxicity testing  tion by methods of animal-based toxicology. Food Chem. Toxicol.
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             (Bhogal et al., 2005). Extending this approach to a wider
                                                                Bhogal, N., Grindon, C., Combes, R., Balls, M., 2005. Toxicity testing:
             range of cell culture systems will improve the prospect of
                                                                  creating a revolution based on new technologies. Trends Biotechnol.
             using in vitro methods for studying a wider range of
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             chronic toxicological phenomena. However, further devel-
                                                                Breier, J.M., Gassmann, K., Kayser, R., et al., 2010. Neural progeni-
             opment and validation of in vitro models is required if  tor cells as models for high-throughput screens of developmental
             they are to be adopted on a much wider scale in order to  neurotoxicity: state of the science. Neurotoxicol. Teratol. 32,
             secure further reduction, replacement, and refinement of  4 15.
             animal models. This will require further improvements in  Buse, E., Habermann, G., Ostrburg, I., et al., 2003. Reproductive/devel-
             cell culture technology and growth conditions, such as the  opmental toxicity and immunotoxicity assessment in the nonhuman
             increased use of hollow fiber systems to facilitate continu-  primate model. Toxicology. 185, 221 227.
             ous replenishment of media and supplements (Nussler  Cocks, G., Romanyuk, N., Amemori, T., et al., 2013. Conditionally
                                                                  immortalized stem cell lines from human spinal cord retain regional
             et al., 2001). The increased use of microsomal activation
                                                                  identity and generate functional interneurons and motor neurons.
             systems and/or established cell lines transfected with
                                                                  Stem Cell Res. Ther. 4, 69.
             genes for mixed function oxidases is another approach
                                                                Cohen, J., Wilkin, G.P., 1996. Neural Cell Culture. A Practical
             that will help to increase the metabolic competence of
                                                                  Approach. Oxford University Press, Oxford.
             in vitro models. Another promising in vitro approach  Davila, J.C., Rodriguez, R.J., Melchert, R.B., Acosta Jr, D., 1998.
             involves the use of adult or ESCs of human or rodent ori-  Predictive value of in vitro model systems in toxicology. Annu. Rev.
             gin. These cells can be either continuously cultured with-  Pharmacol. Toxicol. 38, 63 96.
             out being differentiated or they can generate a wide  Davila, J.C., Cezar, G.G., Thiede, M., et al., 2004. Use and application
             variety of functional mammalian cell types. In addition to  of stem cells in toxicology. Toxicol. Sci. 79, 214 223.
             its application in developmental toxicity testing, stem cell  Davis, J., 2002. Basic Cell Culture. A Practical Approach. Oxford
             technology has been successfully used to study mechan-  University Press, Oxford.
                                                                deBlois, D., Horlick, R.A., 2001. Endotoxin sensitization to kinin B(1)
             isms of toxicity and to screen new pharmaceutical com-
                                                                  receptor agonist in non-human primate model: haemodynamic and
             pounds for teratogenicity, genotoxicity, hepatotoxicity,
                                                                  pro-inflammatory effects. Br. J. Pharmacol. 132, 327 335.
             and cardiotoxicity (Davila et al., 1998, 2004).
                                                                Dhillon, V.S., Singh, J., Singh, H., Kler, R.S., 1995. In vitro and in vivo
                The development of medium to high throughput meth-
                                                                  genotoxicity of hormonal drugs. VI. Fluoxymesterone. Mutat. Res.
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             with the revolution in bioinformatics, will lead to the  Downs, T.R., Wilfinger, W.W., 1983. Fluorometric quantification of
             accumulation of vast toxicological information, helping to  DNA in cells and tissue. Anal. Biochem. 131, 538 547.
             elucidate mechanisms of toxicity in both in vitro and  Efthymiou, A., Shaltouki, A., Steiner, J.P., et al., 2014. Functional
             in vivo models (Bhogal et al., 2005). These approaches  screening assays with neurons generated from pluripotent stem cell-
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             new biomarkers of effect or exposure.              EPA (Environmental Protection Agency), (1998a). Health Effects Test
                                                                  Guidelines OPPTS 870.7200 Companion Animal Safety. EPA 712-
                In conclusion, although it is a desirable goal to replace
                                                                  C-98-349.
             all animal testing, animal-based toxicological testing is
                                                                EPA (Environmental Protection Agency), (1998b). Health Effects Test
             likely to continue for the foreseeable future. Further
                                                                  Guidelines OPPTS 870.3700 Prenatal Developmental Toxicity
             improvements in animal models will make them more reli-
                                                                  Study. EPA 712-C-98-207.
             able indicators of human toxicity, while the development  EPA (Environmental Protection Agency), (1998c). Health Effects Test
             of improved in vitro systems will eventually minimize the  Guidelines OPPTS 870.5450 Rodent Dominant Lethal Assay. EPA
             use of animals for toxicity studies. The veterinarian’s role  712-C-98-227.
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