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In Metaphysics A, Aristotle makes a curious reference to 'automatic marionettes' (τῶν θαυμάτων ταὐτόματα) as things that inspire metaphysical curiosity. In this article I argue that the reference is an allusion to the difference between his understanding of metaphysical mimesis and that of Plato's. Aristotle's reference to 'self-moving' thaumata, when read contrastively with Plato's static thaumata in the cave allegory, implies that whereas Plato's mimesis is static, Aristotle's is kinetic. Aristotle's claim that puppets are an impetus to metaphysical inquiry becomes less strange when one sees that Plato had suggested something similar. Some of Plato's writings and those of his contemporaries offer evidence that the thaumata in Plato's cave are static, supporting the idea that Aristotle's kinetic thaumata stand in meaningful contrastive allusion to them. I conclude by offering a brief sketch of Aristotle's theory of kinetic mimesis, in which all things manifest principles of circularity, including, significantly, the automatic marionettes that Aristotle mentions in Metaphysics A. [ABSTRACT FROM AUTHOR]

Cadmium and cadmium compounds are contaminants of the environment, food, and drinking water and are important constituents of cigarette smoke. Cd exposure has also been associated with airborne particulate CdO and with Cd-containing quantum dots in medical therapy. Adverse cadmium effects reported in the literature have stimulated during recent years an ongoing discussion to better elucidate cadmium outcomes at cell and molecular level. The present work is designed to gain an insight into the mechanism of p53 impairment at gene and protein level to understand Cd-induced resistance to apoptosis. We used a hepatoma cell line (HepG2) derived from liver, known to be metal responsive. At genotoxic cadmium concentrations no cell cycle arrest was observed. The p53 at gene and protein level was not regulated. Fluorescence images showed that p53 was correctly translocated into the nucleus but that the p21Cip1/WAF-1, a downstream protein of p53 network involved in cell cycle regulation, was not activated at the highest cadmium concentrations used. The miRNAs analysis revealed an upregulation of mir-372, an miRNA able to affect p21Cip1/WAF-1 expression and promote cell cycle progression and proliferation. The role of metallothioneins and possible conformational changes of p53 are discussed. [ABSTRACT FROM AUTHOR]

Existing work demonstrates that animals alternate between engaged and disengaged states during perceptual decision-making. To understand the neural signature of these states, we performed cortex-wide measurements of neural activity in mice making auditory decisions. The trial-averaged magnitude of neural activity was similar in the two states. However, the trial-to-trial variance in neural activity was higher during disengagement. To understand this increased variance, we trained separate linear encoding models on neural data from each state. The models demonstrated that although task variables and task-aligned movements impacted neural activity similarly during the two states, movements that are independent of task events explained more variance during disengagement. Behavioral analyses uncovered that during disengagement, movements become uncoupled to task events. Taken together, these results argue that the neural signature of disengagement, though obscured in trial-averaged neural activity, is evident in trial-to-trial variability driven by changing patterns of spontaneous movements.

Good Cell and Tissue Culture Practice (GCCP) 2.0 is an updated guidance document from GCCP 1.0 (published by ECVAM in 2005), which was developed for practical use in the laboratory to assure the reproducibility of in vitro (cell-based) work. The update in the guidance was essential as cell models have advanced dramatically to more complex culture systems and need more comprehensive quality management to ensure reproducibility and high-quality scientific data. This document describes six main principles to consider when performing cell culture including characterization and maintenance of essential characteristics, quality management, documentation and reporting, safety, education and training, and ethics. The document does not intend to impose detailed procedures but to describe potential quality issues. It is foreseen that the document will require further updates as the science and technologies evolve over time.

The prefrontal cortex (PFC) integrates incoming information to guide our actions. When motivation for food-seeking competes with avoidance of danger, the PFC likely plays a role in selecting the optimal choice. In platform-mediated active avoidance, rats avoid a tone-signaled footshock by stepping onto a nearby platform, delaying access to sucrose pellets. This avoidance requires prelimbic (PL) PFC, basolateral amygdala (BLA), and ventral striatum (VS). We previously showed that inhibitory tone responses of PL neurons correlate with avoidability of shock (Diehl et al., 2018). Here, we optogenetically modulated PL terminals in VS and BLA to identify PL outputs regulating avoidance. Photoactivating PL-VS projections reduced avoidance, whereas photoactivating PL-BLA projections increased avoidance. Moreover, photosilencing PL-BLA or BLA-VS projections reduced avoidance, suggesting that VS receives opposing inputs from PL and BLA. Bidirectional modulation of avoidance by PL projections to VS and BLA enables the animal to make appropriate decisions when faced with competing drives., Competing Interests: MD, JI, JM, GR, FG, VV, GQ No competing interests declared, (© 2020, Diehl et al.)

Good Cell Culture Practices (GCCP) is of high relevance to in vitro toxicology. The European Society of Toxicology In Vitro (ESTIV), the Center for Alternatives for Animal Testing (CAAT) and the In Vitro Toxicology Industrial Platform (IVTIP) joined forces to address by means of an ESTIV 2016 pre-congress session the different aspects and applications of GCCP. The covered aspects comprised the current status of the OECD guidance document on Good In Vitro Method Practices, the importance of quality assurance for new technological advances in in vitro toxicology including stem cells, and the optimized implementation of Good Manufacturing Practices and Good Laboratory Practices for regulatory testing purposes. General discussions raised the duality related to the difficulties in implementing GCCP in an academic innovative research framework on one hand, and on the other hand, the need for such GCCP principles in order to ensure reproducibility and robustness of in vitro test methods for toxicity testing. Indeed, if good cell culture principles are critical to take into consideration for all uses of in vitro test methods for toxicity testing, the level of application of such principles may depend on the stage of development of the test method as well as on the applications of the test methods, i.e., academic innovative research vs. regulatory standardized test method., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

This chapter focuses on practical aspects of conducting prospective in vitro validation studies, and in particular, by laboratories that are members of the European Union Network of Laboratories for the Validation of Alternative Methods (EU-NETVAL) that is coordinated by the EU Reference Laboratory for Alternatives to Animal Testing (EURL ECVAM). Prospective validation studies involving EU-NETVAL, comprising a multi-study trial involving several laboratories or "test facilities", typically consist of two main steps: (1) the design of the validation study by EURL ECVAM and (2) the execution of the multi-study trial by a number of qualified laboratories within EU-NETVAL, coordinated and supported by EURL ECVAM. The approach adopted in the conduct of these validation studies adheres to the principles described in the OECD Guidance Document on the Validation and International Acceptance of new or updated test methods for Hazard Assessment No. 34 (OECD 2005). The context and scope of conducting prospective in vitro validation studies is dealt with in Chap. 4 . Here we focus mainly on the processes followed to carry out a prospective validation of in vitro methods involving different laboratories with the ultimate aim of generating a dataset that can support a decision in relation to the possible development of an international test guideline (e.g. by the OECD) or the establishment of performance standards.

This review looks at the recent findings in the neuroimaging of the psychoses, with a view to clarifying the question of the unitary versus the two-disorder theory of psychosis. Schizophrenia is associated with significantly more cortical grey matter loss than bipolar disorder. The distribution of these losses is different; schizophrenia is characteristically associated with loss of the medial and middle frontal, the superior temporal gyri, and the dorsolateral prefrontal cortex, while bipolar disorder has particular loss in the medial frontal gyrus and the anterior cingulate cortex. Both disorders were associated with extensive white matter deficits. In summary, neuroimaging indicates different patterns of grey matter loss for schizophrenia and bipolar disorder. However, neuroimaging of white matter reveals a good deal of overlap between these two disorders. Thus, neuroimaging does not suggest a unitary psychosis or a two-psychosis model, instead it suggests a two-dimensional psychosis field, on which disorders are located according to two dimensions, the degree of grey matter loss and the degree of white matter abnormality.

Inorganic arsenic (iAs) is a human carcinogen, well known as a clastogenic compound. To evaluate the molecular mechanism of arsenite (iAs(III)) toxicity, we investigated the effects on cell growth and apoptosis, telomere length, telomerase expression, as well as the formation of reactive oxygen species (ROS) in male and female human cord blood cells in vitro. Incubation with iAs(III) at the concentration of 0.0001 microM increased telomerase mRNA and protein expression maintained both telomere length and cellular growth, and induced mRNA over-expression of the two oncogenes ras and myc. Our results suggest that female cord blood cells are more sensitive than male ones to iAs(III) induced telomerase stimulation at low concentrations, possibly related to the increased expression of ras and myc oncogenes. On the contrary, at the concentration of 1 microM, iAs(III) decreased telomerase expression and telomere length, and induced apoptosis, necrosis and production of reactive oxygen species. Buthionine sulfoximine (BSO), an inhibitor of glutathione (GSH) synthesis, markedly increased the percentage of apoptotic cells, suggesting that GSH is fundamental for detoxification of iAs(III) in cord blood cells. The reactive oxygen species (ROS) scavenger, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), protected cord blood cells from iAs(III) toxicity, and prevented telomere shortening and telomerase down-modulation. It can be concluded that telomerase expression and telomere length are associated with iAs(III) induced cell death, via production of reactive oxygen species, as well as with iAs(III) induced effects on cell differentiation processes and rate of cell growth.

Inorganic arsenic (iAs) and its metabolites are transferred to the foetus through the placental barrier and this exposure can compromise the normal development of the unborn. For this reason, we assessed the toxicity of sodium arsenite (iAs(III)) and its metabolites dimethylarsinic acid (DMA(V)), monomethylarsonic acid (MMA(V)) and monomethylarsonous acid (MMA(III)) on human haematopoietic cord blood cells and murine bone marrow progenitors in vitro, looking at the effects induced at different concentrations in the two genders. The expression of two enzymes responsible for arsenic biotransformation arsenic methyltranferase (AS3MT) and glutathione S-transferase omega 1 (GSTO1) was evaluated in human cord blood cells. Cord blood and bone marrow cells were exposed in vitro to iAs(III) at a wide range of concentrations: from 0.0001 microM to 10 microM. The methylated arsenic metabolites were tested only on human cord blood cells at concentrations ranging from 0.00064 microM to 50 microM. The results showed that iAs(III) was toxic on male and female colony forming units to about the same extent both in human and in mouse. Surprisingly, very low concentrations of iAs(III) increased the proliferation rate of both human and murine female cells, while male cells showed no significant modulation. MMA(V) and DMA(V) did not exert detectable toxicity on the cord blood cells, while MMA(III) had a marked toxic effect both in male and female human progenitors. AS3MT mRNA expression was not induced in human cord blood cells after iAs(III) exposure. GSTO1 expression decreased after MMA(III) treatment. This study provides evidence that exposure to iAs(III) and MMA(III) at muM concentrations is associated with immunosuppression in vitro.

It is a requirement that parenteral medicines be tested for pyrogens (fever causing agents) using one of two animal-based tests: the rabbit pyrogen test and the bacterial endotoxin test. Understanding the human fever reaction has led to novel non-animal alternative tests based on in vitro activation of human monocytoid cells in response to pyrogens. Using 13 prototypic drugs, clean or contaminated with pyrogens, we have validated blindly six novel pyrogen tests in ten laboratories. Compared with the rabbit test, the new tests have a lower limit of detection and are more accurate as well as cost and time efficient. In contrast to the bacterial endotoxin test, all tests are able to detect Gram-positive pyrogens. The validation process showed that at least four of the tests meet quality criteria for pyrogen detection. These validated in vitro pyrogen tests overcome several shortcomings of animal-based pyrogen tests. Our data suggest that animal testing could be completely replaced by these evidence-based pyrogen tests and highlight their potential to further improve drug safety.

Acrylonitrile is a very high volume industrial chemical used primarily in the manufacture of plastics and rubber, which displays a pronounced acute toxicity and may be carcinogenic. The damage to the hematopoietic function by acrylonitrile may result from interference with cytokine production and cytokine receptor binding. Our present data show that acrylonitrile modulates the expression of some genes implicated in cell differentiation, cell-cycle progression, and clonogenic potential of human cord blood cells. A macroarray hybridization analysis showed that expression of the CXCR4, MCP-1, and MRP8 genes was modified by acrylonitrile exposure. Moreover, the acrylonitrile cell target seems to be the myeloid compartment, as assessed by a CFU-GM assay. In particular, the downregulation of CXCR4, MCP1, and MRP8 can be responsible for the observed reduction of cell proliferation and clonogenic capability of CFU-GM precursors. A Western blot assay showed an acrylonitrile-dependent induction of Bax, while Bcl-2 expression changed only after 48 h of chemical exposure. Bax was overexpressed in respect to Bcl-2, and this fact can be responsible for the induction in cell death after 24 h of treatment. C-fos and c-jun were also downregulated after 24 h and 6 h of treatment, respectively., (Copyright 2005 Wiley Periodicals, Inc)

Styrene is one of the most important monomers produced worldwide, and it finds major use in the production of polystyrene, acrylonitrile-butadiene-styrene resins and unsaturated polystyrene resins. Epidemiological studies on styrene showed that the malignancies observed most frequently in humans after exposure are related to the lymphatic and haemopoietic system. IARC classified styrene a possible carcinogenic to humans (Group 2B). In this study, we evaluated the effect of styrene on gene expression profiles of human cord blood cells, as well as its activity on the apoptosis and bcl-2 related protein expression. Data demonstrated that, after 24 and 48 h of exposure, styrene (800 microM) induced an increase in the necrosis of mononuclear cord blood cells, whereas it did not cause any increase in the apoptotic process. Western blot analysis revealed a modified expression of Bax, BCl-2, c-Jun, c-Fos and Raf-1 proteins in the human cord blood cells after direct exposure to styrene, whereas p53 expression did not change. Furthermore, Macroarray analysis showed that styrene changed cord blood gene expression, inducing up-regulation of monocyte chemotactic protein 1 (MCP-1), and down-regulation of CC chemokine receptor type 1 (CCR-1) and SLP-76 tyrosine-phosphoprotein.

In this study, the effect of naphthalene on the induction of apoptosis and gene expression profiles in cord blood cells has been evaluated, as well as its activity on the BCL-2 related protein expression. After 6, 24, and 48 h of exposure to naphthalene (500 microM), a decrease in cell death was observed: the cells became more resistant to the toxicant and capable of surviving after the treatment. A Western blot analysis revealed an overexpression of BCL-2, c-JUN, c-FOS, and RAF-1 proteins, which are involved in the antiapoptotic response and in the regulation of cell growth, differentiation, and development. Furthermore, macroarray analysis showed that naphthalene modified cord blood gene expression, inducing IL-8 precursor and T-cell transcription factor and decreasing the level of RNA-binding protein FUS/TLS., (Copyright 2003 Wiley Periodicals, Inc. J Biochem Mol Toxicol 17:286-294, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.10091)