35 research outputs found
Titanium Dioxide and Zinc Oxide Nanoparticles Are Not Mutagenic in the Mouse Lymphoma Assay But Modulate the Mutagenic Effect of Uv-C-Light Post Treatment
No full textWOS: 000395724300055There are no studies in the literature on nanomaterials (NMs) using gene mutation approaches in mammalian cells, which represents an important gap for genotoxic risk estimations. To fill this gap, mouse lymphoma L5178Y Tk(+/-) assay (MLA) was used to evaluate the mutagenic effect of titanium dioxide and zinc oxide nanoparticles (NPs). Two different NP sizes (between 1-50 and 50-100 nm) of each NP were used. The results indicate that both the selected NMs and their microparticulated forms do not have mutagenic effects. Nevertheless, pre-exposure to these NMs reduce the mutagenic effect of posterior UVC-light exposure, in an indirect concentration-effect relationship. As such, cells previously exposed to low concentrations of the selected NPs show better protective effects against posterior exposure to UVC-light. These in vitro results, obtained from mouse lymphoma cells, support the reproduction of the current literature date on these NPs' genotoxic potential as well as to focus on the discussion on the benefits/risks associated with their use in photo protection sunscreens.Scientific and Technological Research Council of Turkey (TUBITAK), Science Fellowships and Grant Programmes Department (BIDEB), International Post Doctoral Research Fellowship Programme, Ankara (Turkey) [2219]; Generalitat de Catalunya (CIRIT)Generalitat de Catalunya [2014SGR-202]Esref Demir was supported by a postdoctoral fellowship from the Scientific and Technological Research Council of Turkey (TUBITAK), Science Fellowships and Grant Programmes Department (BIDEB), 2219-International Post Doctoral Research Fellowship Programme, Ankara (Turkey). This investigation has been supported in part by the Generalitat de Catalunya (CIRIT, 2014SGR-202). We wish to thank Gloria Umbert for her excellent technical assistance
Toxic and genotoxic effects of graphene and multi-walled carbon nanotubes
No full textDemir, Esref/0000-0002-2146-7385WOS: 000435122700004PubMed: 29873610Graphene and multi-walled carbon nanotubes (MWCNT) are widely used in nanomedicine, and other fields, due to their unique physicochemical properties including high tensile strength, ultra-light weight, thermal and chemical stability, and reliable semi-conductive electronic properties. Although extensive amount of data exist describing their adverse effects including potential genotoxicity, few studies using gene mutation detection approaches in mammalian cells are available, which represents an important gap for risk estimations. The aim of the present study was to determine the effects of graphene or MWCNT [as pure, carboxyl (COOH) functionalized, and amide (NH2) functionalized] on cytotoxicity, intracellular levels of reactive oxygen species, apoptosis, gene expression changes, and gene mutation induction in L5178Y/Tk(+/-)3.7.2C mouse lymphoma cell line. Although some adverse effects were observed at concentrations of 350 and 450 mu g/ml, which are excessive and not environmentally relevant levels, no marked effects were detected at concentrations of 250 mu g/ml and lower. This is the first study reporting cytotoxicity, mutagenicity, and gene expression findings in the mouse lymphoma cell line for graphene and different MWCNT forms at high concentrations; however, the biological relevance of these observations needs to be assessed following chronic in vivo exposure
Drosophila as a robust model system for assessing autophagy: a review
No full textAutophagy is the process through which a body breaks down and recycles its own cellular components, primarily inside lysosomes. It is a cellular response to starvation and stress, which plays decisive roles in various biological processes such as senescence, apoptosis, carcinoma, and immune response. Autophagy, which was first discovered as a survival mechanism during starvation in yeast, is now known to serve a wide range of functions in more advanced organisms. It plays a vital role in how cells respond to stress, starvation, and infection. While research on yeast has led to the identification of many key components of the autophagy process, more research into autophagy in more complex systems is still warranted. This review article focuses on the use of the fruit fly Drosophila melanogaster as a robust testing model in further research on autophagy. Drosophila provides an ideal environment for exploring autophagy in a living organism during its development. Additionally, Drosophila is a well-suited compact tool for genetic analysis in that it serves as an intermediate between yeast and mammals because evolution conserved the molecular machinery required for autophagy in this species. Experimental tractability of host–pathogen interactions in Drosophila also affords great convenience in modeling human diseases on analogous structures and tissues.No sponso
Environmental Toxicology and Human Health
No full textHumans and animals may be exposed on a continuous daily basis to a mixture of environmental contaminants that may cause adverse consequences. This Topic focuses on environmental pollutants including heavy metals, pesticides, nanoparticles, micro-nanoplastics, indoor air pollutants, pharmaceuticals, and industrial toxicants with effects on human health, risk assessment, and the relationship between various diseases and environmental pollutants. The aim of this Topic is to present a comprehensive overview of various studies carried out with in vivo and in vitro model organisms and the potential risks posed by environmental pollutants to human health. In this Topic, 20 original articles, 6 reviews and 1 communication are collected, with a particular focus on alcohol-based hand sanitizers, polycyclic aromatic hydrocarbons, monochromatic light pollution, paraben as an endocrine disruptor, heavy metal pollution attributed to the antimony and arsenic found in mines in soil, water, and sediments, groundwater with high fluoride levels, the transmission of viruses due to the heating, ventilation, and air conditioning systems of urban subways, chronic home radon exposure, organotin compounds, heavy metal pollutants, polypropylene microplastics, ventral body wall defects in chick embryos, microcystin-LR as an aquatic toxin, N-nitroso compounds, methylmercury as a global pollutant, triazine herbicides, persistent organic pollutants, bisphenol A and trace metals, autophagy, nano- and micro-sized polystyrene particles, tributyltin as an environmental contaminant, polybrominated diphenyl ethers, and per- and polyfluoroalkyl substances
Islamophobia from the inside: how Turkish immigrants responded to the securitization of integration in Germany and the Netherlands
No full textAlthough there is a vast literature on the securitization and Islamophobia phenomena in Western societies, there is relatively less research about the perceptions and mobilization of Muslim immigrants in the West, especially Turks, with respect to these phenomena. Therefore, the research set out to explore whether there has been any change in the forms of mobilization of Turkish immigrants in Germany and the Netherlands after 9/11 as a response to the securitization of integration. The present comparative study identified not only the changes after 9/11, but also the main similarities and differences between the two cases. Characteristics of Turkish immigrants and the context of reception, as well as the subjective aspects (such as perceptions, feelings, emotions, and so on) related to the issue were taken into account in the study. From the methodological perspective, the study employed a mixed methods research approach by including interviews, participant observation, and a quantitative analysis of population and political representation data. In total, in Germany and the Netherlands, 27 face to face semi-structured interviews were conducted with either the representatives of Turkish organizations or the political party members that originated from Turkey. The study concluded that Turkish immigrants in both countries have been negatively affected by the securitization process. They felt that they faced more problems (such as discrimination, hate crimes, more restrictive policies towards them, and so on) in their contexts after 9/11. Along with these perceptions, the changes in their characteristics and the context of reception played an important role in their mobilization in this process. The study revealed that they became more mobilized and organized after 9/11. After evaluating the motives and objectives of mobilization and acculturation strategies of Turkish immigrants, the study identified three main forms of mobilization (political, social, and cultural) as a response to the securitization of integration. Not only differences between the characteristics of Turkish immigrants in Germany and the Netherlands but also dissimilarities in their receiving contexts resulted in differences in their political mobilization approaches. However, their social and cultural mobilization approaches in both countries have mainly been similar.Ph.D.Includes bibliographical referencesIncludes vitaby Esref Ertur
Genotoxicity responses of single and mixed exposure to heavy metals (cadmium, silver, and copper) as environmental pollutants in Drosophila melanogaster
No full text<p>Heavy metals are now persistently present in living things' environments, in addition to their potential toxicity. Therefore, the aim of this study was to utilize D. melanogaster to determine the biological effects induced by different heavy metals including cadmium chloride (CdCl2), copper (II) sulfate pentahydrate (CuSO 4.5 H2O), and silver nitrate (AgNO3). In vivo experiments were conducted utilizing three low and environmentally relevant concentrations from 0.01 to 0.5 mM under single and combined exposure scenarios on D. melanogaster larvae. The endpoints measured included viability, reactive oxygen species (ROS) generation and genotoxic effects using Comet assay and the wing-spot test. Results indicated that tested heavy metals were not toxic in the egg-to adult viability. However, combined exposure (CdCl2+AgNO3 and CdCl2+AgNO3+CuSO 4.5 H2O) resulted in significant genotoxic and unfavorable consequences, as well as antagonistic and/or synergistic effects on oxidative damage and genetic damage.</p>
Absence of Adverse Effects on Pulmonary Histopathology and Functions Following Inhalation Exposure to Chloromethylisothiazolinone/Methylisothiazolinone
No full textIn South Korea, issues have been raised regarding exposure to humidifier disinfectant products containing certain chemicals postulated to induce lung diseases in consumers. Several rodent studies utilizing whole-body inhalation, which comprises freely moving animals breathing through the nares, and intranasal instillation involving restraint, were conducted by various Korean Governmental Agencies on these products to investigate whether there is a causal relationship between these products and the development of lung diseases. In particular, the humidifier disinfectant product Kathon, containing chloromethylisothiazolinone and methylisothiazolinone (CMIT and MIT), when directly introduced into inhalation chambers at varying concentrations for up to 13 weeks, produced no significant histopathological alterations and no marked changes in pulmonary function parameters. Further, there was no evidence of cytotoxicity; total and differential cell counts did not differ from control. In addition, the levels of cytokine markers of inflammation were not markedly altered. In contrast to published papers utilizing intratracheal and intranasal instillation, where the animal is anesthetized and chemical bypasses the defense mechanisms in the respiratory tract, then reaches the pulmonary region, ignoring recommended dose levels was found to initiate fibrotic responses in mice and rats. However, the usefulness of experimental results to extrapolate to humans obtained following intratracheal and intranasal instillation studies is of limited value because the data generated did not use a realistic design and appropriate dosimetry. Therefore, these findings have significant drawbacks in their use to characterize an inhalation risk for pulmonary fibrosis in humans and cannot be used for the extrapolation of such risk to humans. It is thus evident that the inhalation data generated by the Korean Regulatory Agencies are more realistic and show that exposure to CMIT and MIT does not initiate pulmonary fibrosis. Although inhalation studies still do not fully replicate real-world human exposure scenarios and have limitations for direct extrapolation to humans, they are nevertheless more appropriate than intratracheal or intranasal instillation models
More Than Vision : The Works of Three Blind Artists
No full text64 p.The author discusses the experience of the blind with visual arts and reviews the life and work of American sculptor Michael Naranjo, photographers David Plakke and Tim Vallender, and Turkish painter Esref Armagan
Genotoxic effects of synthetic amorphous silica nanoparticles in the mouse lymphoma assay
No full textSynthetic amorphous silica nanoparticles (SAS NPs) have been used in various industries, such as plastics, glass, paints, electronics, synthetic rubber, in pharmaceutical drug tablets, and a as food additive in many processed foods. There are few studies in the literature on NPs using gene mutation approaches in mammalian cells, which represents an important gap for genotoxic risk estimations. To fill this gap, the mouse lymphoma L5178Y/Tk+/− assay (MLA) was used to evaluate the mutagenic effect for five different concentrations (from 0.01 to 150 μg/mL) of two different sizes of SAS NPs (7.172 and 7.652 nm) and a fine collodial form of silicon dioxide (SiO2). This assay detects a broad spectrum of mutational events, from point mutations to chromosome alterations. The results obtained indicate that the two selected SAS NPs are mutagenic in the MLA assay, showing a concentration-dependent effect. The relative mutagenic potencies according to the induced mutant frequency (IMF) are as follows: SAS NPs (7.172 nm) (IMF = 705.5 × 10−6), SAS NPs (7.652 nm) (IMF = 575.5 × 10−6), and SiO2 (IMF = 57.5 × 10−6). These in vitro results, obtained from mouse lymphoma cells, support the genotoxic potential of NPs as well as focus the discussion of the benefits/risks associated with their use in different areas. Keywords: Synthetic amorphous silica nanoparticles, Mouse lymphoma assay, Mutagenic agents, Thymidine kinase (Tk) gene, In vitro mutagenicit
