Nanosilver is one of the most commonly used engineered nanomaterials (ENMs). In our study we focused on assessing the size-dependence of the toxicity of nanosilver (Ag ENMs), utilising materials of ...three sizes (50, 80 and 200 nm) synthesized by the same method, with the same chemical composition, charge and coating.
Uptake and localisation (by Transmission Electron Microscopy), cell proliferation (Relative growth activity) and cytotoxic effects (Plating efficiency), inflammatory response (induction of IL-8 and MCP-1 by Enzyme linked immune sorbent assay), DNA damage (strand breaks and oxidised DNA lesions by the Comet assay) were all assessed in human lung carcinoma epithelial cells (A549), and the mutagenic potential of ENMs (Mammalian hprt gene mutation test) was assessed in V79-4 cells as per the OECD protocol. Detailed physico-chemical characterization of the ENMs was performed in water and in biological media as a prerequisite to assessment of their impacts on cells. To study the relationship between the surface area of the ENMs and the number of ENMs with the biological response observed, Ag ENMs concentrations were recalculated from μg/cm2 to ENMs cm2/cm2 and ENMs/cm2.
Studied Ag ENMs are cytotoxic and cytostatic, and induced strand breaks, DNA oxidation, inflammation and gene mutations. Results expressed in mass unit μg/cm2 suggested that the toxicity of Ag ENMs is size dependent with 50 nm being most toxic. However, re-calculation of Ag ENMs concentrations from mass unit to surface area and number of ENMs per cm2 highlighted that 200 nm Ag ENMs, are the most toxic. Results from hprt gene mutation assay showed that Ag ENMs 200 nm are the most mutagenic irrespective of the concentration unit expressed.
We found that the toxicity of Ag ENMs is not always size dependent. Strong cytotoxic and genotoxic effects were observed in cells exposed to Ag ENMs 50 nm, but Ag ENMs 200 nm had the most mutagenic potential. Additionally, we showed that expression of concentrations of ENMs in mass units is not representative. Number of ENMs or surface area of ENMs (per cm2) seem more precise units with which to compare the toxicity of different ENMs.
Topicality. Today, the New Ukrainian School was introduced, and with it, inclusive education. The importance of providing high-quality educational services for schoolchildren is growing. Scientific ...research devoted to the fundamental aspects of inclusive physical education appears to be insufficient. The Purpose of the work is to establish a rating of factors that prevent the effective organization of the physical education process in inclusive classes of general secondary education institutions; to find out which approaches are important for physical education in inclusive classrooms to be effective. Methods. A survey of physical education teachers (n=73) was conducted. Consistency of respondents’ answers was determined using Kendall’s concordance coefficient. The Results. Among the main problems are the imperfection of the legislative framework, the lack of proper content of the program material, limited access to methodical support for inclusive physical education lessons. It is also necessary to solve the problems associated with ignoring the motivation of students and the low level of children’s physical condition. Problems also arise as a result of the mismatch of human resources with modern needs. The lack of objective information about the health and physical development of schoolchildren, an imperfect system of medical and pedagogical control, in particular, incorrect criteria for dividing students of inclusive classes into groups make it difficult to form homogeneous groups in an inclusive class. Teachers need support from specialists in the field of medicine and rehabilitation. Conclusions. The survey of teachers confirms the presence of numerous obstacles in the physical education of students in inclusive classes. The introduction of the position of a rehabilitation teacher can significantly increase the effectiveness of physical education lessons in inclusive classes. In order for the physical education lesson in inclusive classes to be effective, it is important to divide the class into homogeneous groups that are small in number of participants depending on the level of children’s abilities and for each of them to adapt the means and differentiate the volume and intensity of the load. Modification of equipment for students with special educational needs is rational.
Актуальність. Сьогодні запроваджено Нову українську школу, а з нею – й інклюзивну освіту. Зростає важливість забезпечення якісних освітніх послуг для школярів. Наукових досліджень щодо фундаментальних аспектів інклюзивного фізичного виховання виявляється недостатньо. Мета роботи – установити рейтинг чинників, які перешкоджають ефективній організації процесу фізичного виховання в інклюзивних класах закладів загальної середньої освіти; з’ясувати підходи, важливі для того, щоб фізичне виховання в інклюзивних класах було ефективним. Методологія. Здійснено опитування вчителів фізичної культури (n=73). Узгодженість відповідей респондентів визначали за допомогою коефіцієнта конкордації Кендалла. Результати. Серед основних проблем визначаються недосконалість законодавчої бази, відсутність належного змісту програмного матеріалу, обмежений доступ до методичного забезпечення для інклюзивних уроків фізичної культури. Також потрібно розвʼязувати проблеми, пов’язані з ігноруванням мотивації учнів та низьким рівнем фізичного стану дітей. Проблеми також виникають унаслідок невідповідності кадрових ресурсів сучасним потребам. Недостат- ність об’єктивної інформації про здоров’я й фізичний розвиток школярів, недосконала система медико- педагогічного контролю, зокрема некоректні критерії поділу учнів інклюзивних класів на групи ускладнюють формування однорідних груп в інклюзивному класі. Учителі потребують підтримки від спеціалістів у галузі медицини й реабілітації. Висновки. Опитування вчителів підтверджує наявність численних перешкод у фізич- ному вихованні учнів інклюзивних класів. Уведення посади вчителя-реабілітолога може значно підвищити ефективність уроків фізичної культури в інклюзивних класах. Для того щоб урок фізичної культури в інклюзивних класах був ефективним, важливо поділити клас на однорідні, невеликі за кількістю учасників групи залежно від рівня можливостей дітей і для кожної з них адаптувати засоби та диференціювати обсяг й інтенсивність навантаження. Раціональною є модифікація обладнання для учнів з особливими освітніми потребами.
Abstract
Applying validated in vitro assays to the study of nanoparticle toxicity is a growing trend in nanomaterial risk assessment. Precise characterisation of reference nanomaterials and a ...well-regulated in vitro testing system are required to determine the physicochemical descriptors which dictate the toxic potential of nanoparticles. The use of automated, high-throughput technologies to facilitate the identification and prioritisation of nanomaterials which could pose a risk is desirable and developments are underway. In this study, two mammalian fibroblast lines (Balb/c 3T3 and COS-1 cells) were treated with a range of concentrations of iron oxide nanomaterials manufactured for use in medical diagnostics, using an automated platform and high-content-imaging endpoints for cell viability, oxidative stress and DNA damage (double-strand breaks). At the same time, the high-throughput comet assay was employed to measure DNA strand breaks and oxidised bases. Our results show that these methods provide a fast way to determine the toxicity of coated and uncoated iron oxide nanoparticles and, furthermore, to predict the mechanism of toxicity in vitro.
The quality and relevance of nanosafety studies constitute major challenges to ensure their key role as a supporting tool in sustainable innovation, and subsequent competitive economic advantage. ...However, the number of apparently contradictory and inconclusive research results has increased in the past few years, indicating the need to introduce harmonized protocols and good practices in the nanosafety research community. Therefore, we aimed to evaluate if best-practice training and inter-laboratory comparison (ILC) of performance of the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay for the cytotoxicity assessment of nanomaterials among 15 European laboratories can improve quality in nanosafety testing. We used two well-described model nanoparticles, 40-nm carboxylated polystyrene (PS-COOH) and 50-nm amino-modified polystyrene (PS-NH2). We followed a tiered approach using well-developed standard operating procedures (SOPs) and sharing the same cells, serum and nanoparticles. We started with determination of the cell growth rate (tier 1), followed by a method transfer phase, in which all laboratories performed the first ILC on the MTS assay (tier 2). Based on the outcome of tier 2 and a survey of laboratory practices, specific training was organized, and the MTS assay SOP was refined. This led to largely improved intra- and inter-laboratory reproducibility in tier 3. In addition, we confirmed that PS-COOH and PS-NH2 are suitable negative and positive control nanoparticles, respectively, to evaluate impact of nanomaterials on cell viability using the MTS assay. Overall, we have demonstrated that the tiered process followed here, with the use of SOPs and representative control nanomaterials, is necessary and makes it possible to achieve good inter-laboratory reproducibility, and therefore high-quality nanotoxicological data.
Abstract
Given the multiplicity of nanoparticles (NPs), there is a requirement to develop screening strategies to evaluate their toxicity. Within the EU-funded FP7 NanoTEST project, a panel of ...medically relevant NPs has been used to develop alternative testing strategies of NPs used in medical diagnostics. As conventional toxicity tests cannot necessarily be directly applied to NPs in the same manner as for soluble chemicals and drugs, we determined the extent of interference of NPs with each assay process and components. In this study, we fully characterized the panel of NP suspensions used in this project (poly(lactic-co-glycolic acid)-polyethylene oxide PLGA-PEO, TiO2, SiO2, and uncoated and oleic-acid coated Fe3O4) and showed that many NP characteristics (composition, size, coatings, and agglomeration) interfere with a range of in vitro cytotoxicity assays (WST-1, MTT, lactate dehydrogenase, neutral red, propidium iodide, 3H-thymidine incorporation, and cell counting), pro-inflammatory response evaluation (ELISA for GM-CSF, IL-6, and IL-8), and oxidative stress detection (monoBromoBimane, dichlorofluorescein, and NO assays). Interferences were assay specific as well as NP specific. We propose how to integrate and avoid interference with testing systems as a first step of a screening strategy for biomedical NPs.
The main goal of this research was to study the interactions of a fully characterized set of silver nanomaterials (Ag ENMs) with cells in vitro, according to the standards of Good Laboratory ...Practices (GLP), to assure the quality of nanotoxicology research. We were interested in whether Ag ENMs synthesized by the same method, with the same size distribution, shape and specific surface area, but with different charges and surface compositions could give different biological responses.
A range of methods and toxicity endpoints were applied to study the impacts of interaction of the Ag ENMs with TK6 cells. As tests of viability, relative growth activity and trypan blue exclusion were applied. Genotoxicity was evaluated by the alkaline comet assay for detection of strand breaks and oxidized purines. The mutagenic potential of Ag ENMs was investigated with the in vitro HPRT gene mutation test on V79-4 cells according to the OECD protocol. Ag ENM agglomeration, dissolution as well as uptake and distribution within the cells were investigated as crucial aspects of Ag ENM toxicity. Ag ENM stabilizers were included in addition to positive and negative controls.
Different cytotoxic effects were observed including membrane damage, cell cycle arrest and cell death. Ag ENMs also induced various kinds of DNA damage including strand breaks and DNA oxidation, and caused gene mutation. We found that positive Ag ENMs had greater impact on cyto- and genotoxicity than did Ag ENMs with neutral or negative charge, assumed to be related to their greater uptake into cells and to their presence in the nucleus and mitochondria, implying that Ag ENMs might induce toxicity by both direct and indirect mechanisms.
We showed that Ag ENMs could be cytotoxic, genotoxic and mutagenic. Our experiments with the HPRT gene mutation assay demonstrated that surface chemical composition plays a significant role in Ag ENM toxicity.
The changes in the economy impact on increasing importance of professionals. Businesses are increasingly recognizing the impact of human capital to create value for the company. Therefore, are ...created some special systems for training, development, motivation, and employee development programmes. To this group we can include talent management programmes, which are to maintain, develop, and motivate employees deemed talents. The aim of the article is to present the issues related to talent management programmes and determine the impact and role of mentoring in these programmes. Article is a theoretical and empirical.
The comet assay is widely used to test the genotoxicity of engineered nanomaterials (ENMs) but outcomes may vary when results from different laboratories, or even within one laboratory, are compared. ...We address some basic methodological considerations, such as the importance of carrying out physico-chemical characterisation of the ENMs in test-medium, performing uptake and cytotoxicity tests, and testing several genotoxicity-related endpoints. In this commentary, we discuss the different ways in which concentration of ENMs can be expressed, and stress the need to include appropriate controls and reference standards to monitor variation and avoid interference. Treatment conditions, including cell number, cell culture plate format and volume of treatment medium on the plate are crucial factors that may impact on results and thus should be kept constant within the study.
PDF
