Národní úložiště šedé literatury Nalezeno 11 záznamů.  1 - 10další  přejít na záznam: Hledání trvalo 0.02 vteřin. 
The role of dispersion medium on nanoparticle aggregation and size in biological systems
Červená, Tereza ; Rössnerová, Andrea ; Závodná, Táňa ; Vrbová, Kristýna ; Sikorová, Jitka ; Topinka, Jan ; Rössner ml., Pavel
The use of nanomaterials (NMs) in different areas has been rising for more than a decade. Along with this growth, there is visible development of different testing tools and approaches for measuring the actual size of nanomaterials in biological systems. Test conditions during in vitro toxicological assays are different from the standard conditions under which nanomaterials are characterized and careful evaluation of results is needed. The unique properties and range variety of NMs require the close look how the NMs behave in different dispersion medium over time. In this study we present the results of five types of well-characterized NMs (TiO2: NM-101 and NM-103, SiO2: NM-200, Ag: NM-300K and NM-302) of specific size and shape. The hydrodynamic size and Zeta potentials in suspensions were measured using a dynamic light scattering technique (DLS) (Zetasizer Nano ZS, Malvern, UK). The DLS method is suitable for spherical particles, nevertheless, all samples were measured in order to obtain a rough insight into agglomerate formation in the medium. NM300, NM302, and NM200 aggregated rapidly in the media, thus the cells would be most likely exposed to settled big aggregates then small clusters or individual particles. More stable NMs (NM100 and NM103) showed slight grow along with cultivation time or concentration corresponding to cluster formation. Cells exposed to those NMs would be in contact with small clusters and aggregates of NMs. Measured zeta potentials fluctuated around the stability limit corresponding to observed aggregation.
Ultrafine particles and their possible role in etiology and development of neurodegenerative diseases
Topinka, Jan ; Závodná, Táňa ; Rössnerová, Andrea ; Rössner ml., Pavel
Air pollutants have been shown to cause a vast amount of different adverse health effects. These effects include impairment of many respiratory (e.g. asthma, chronic obstructive pulmonary disease) and cardiovascular (ischemic heart disease, infarction, stroke) diseases. However, in recent years, the evidence showing effects beyond the lungs and circulatory system are becoming more evident. Neurological diseases, namely Alzheimer's disease (AD) has shown to be associated with living near traffic. However, reason for this has remained unresolved until today. Our new H2020 project TUBE aims on revealing the mechanisms of action of ultrafine particles involved in neurological diseases. The TUBE consortium includes experts in areas of aerosol technology, emission research, engine and fuel research, human clinical studies, epidemiology, emission inventories, inhalation toxicology, neurotoxicology and disease mechanism studies. This enables research of resolving the effects of nanoparticles from different traffic modes for both air quality and concomitant toxic effect of these air pollutants. We will investigate adverse effects of air pollutants using cell cultures, animal exposures and volunteered human exposures as well as the material from epidemiological cohort study. These are going to be compared according to inflammatory, cytotoxic and genotoxic changes and furthermore beyond the current state of the art to neurotoxic and brain health effects. With this approach, we are aiming to a comprehensive understanding of the adverse brain effects of nanoparticles from traffic.
Toxic responses in human lung epithelial cells (BEAS-2B) exposed to particulate matter exhaust emissions from gasoline and biogasoline
Závodná, Táňa ; Líbalová, Helena ; Vrbová, Kristýna ; Sikorová, Jitka ; Vojtíšek-Lom, M. ; Beránek, V. ; Pechout, M. ; Kléma, J. ; Cigánek, M. ; Machala, M. ; Neča, J. ; Rössner ml., Pavel ; Topinka, Jan
Motor vehicle emissions substantially contribute to air pollution worldwide and cause serious health problems. While the deleterious effects of diesel exhaust particulate matter (PM) have been widely studied, much less attention is paid to toxicity of PM emitted by gasoline engines although they also produce considerable amount of PM. The primary objective of this research was to assess toxic potencies of exhaust PM released by conventional gasoline engine fueled with neat gasoline (EU) or gasoline-ethanol blend (15% ethanol, v/v, E15). Despite a similar particle mass (mu g PM/kg fuel) produced by both fuels, PM emitted by E15 contained higher amount of harmful polycyclic aromatic hydrocarbons (PAH) as suggested by chemical analysis. To examine the toxicity of organic PM constituents, human lung BEAS-2B cells were exposed for 4h and 24h to a subtoxic dose of E0 and E15 PM organic extracts. We used genome scale transcriptomic analysis to characterize the toxic response and to identify modulated biological process and pathways. Whereas 4h exposure to both PM extracts resulted in modulation of similar genes and pathways related to lipid and steroid metabolism, activation of PPAR alpha, oxidative stress and immune response, 24h exposure was more specific for each extract, although both induced expression of PAH-metabolic enzymes, modulated metabolism of lipids or activated PPAR alpha, E15 additionally deregulated variety of other pathways. Overall, the PM mass produced by both fuels was similar, however, higher PAH content in E15 PM organic extract may have contributed to more extensive toxic response particularly after 24h exposure in BEAS-2B cells.
Males-females differences in the spectrum of chromosomal aberrations in the group of nanocomposites production workers
Rössnerová, Andrea ; Pelcová, D. ; Ždímal, Vladimír ; Elzeinova, Fatima ; Margaryan, Hasmik ; Chvojková, Irena ; Topinka, Jan ; Schwarz, Jaroslav ; Ondráček, Jakub ; Koštejn, Martin ; Komarc, M. ; Vlčková, Š. ; Fenclová, Z. ; Lischková, L. ; Dvořáčková, Š. ; Rössner ml., Pavel
An increase in the use of nanomaterials (NM) has been witnessed in many areas of human life. Therefore, assessment of genotoxicity of NM and nanoparticles (NP) is one of the main objectives of genetic toxicology. Despite this fact, human cytogenetic studies following the exposure to NP are still rare. Moreover, no relevant information on possible differences in sensitivity to NP related to gender is available.\n\nIn this study we periodically (in September 2016, 2017 and 2018; pre-shift and post-shift each year) analyzed a group of workers (both genders), working long time in nanocomposites research, and matched controls. Aerosol exposure monitoring of particulate matter including nano-sized fractions was carried out during working shift. Micronucleus assay using Human Pan Centromeric probes, was applied to distinguish, besides the frequency of total MN in binucleated cells (BNC), also other types of chromosomal damage (losses and breaks). Moreover, whole-chromosome painting (WCP) for autosome #1 and both gonosomes (X and Y) were applied in third sampling period (2018) with the aim to identify the particular structural and numerical chromosomal aberrations.\n\nObtained results showed: (i) differences in the risk of exposure to NP related to individual working processes (welding, smelting and machining); (ii) differences in chemical composition of nano-fraction; (iii) no effect of chronic exposure of NP (total MN) opposite to significant effect of acute exposure; (iv) gender-related DNA damage differences (females seem to be more sensitive to chromosomal losses). Additional data from WCP suggested increased frequency of numerical aberrations in gonosomes.
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Biomarkers of Oxidative Stress and Inflammation in Researches Exposed to Nanoparticles by Inhalation During the Handling of Nanocomposites.
Pelclová, D. ; Ždímal, Vladimír ; Schwarz, Jaroslav ; Komarc, M. ; Vlčková, Š. ; Fenclová, Z. ; Lischková, L. ; Dvořáčková, Š. ; Rössnerová, Andrea ; Rössner ml., Pavel
At present, little is known about the health effects in the workers processing nanocomposites. In our study, 20 researchers (41.8 +/- 11.4 y/o), handling nanocomposites for 17.8 +/- 10.0 years were examined pre-shift and post-shift, together with 21 controls (42.7 +/- 11.5 y/o). Biomarkers of oxidative stress derived from lipids, nucleic acids, proteins and markers of inflammation were analyzed in the exhaled breath condensate (EBC). Aerosol exposure was monitored during three nanoparticle generation operations: smelting, welding and nanocomposite machining. Mass concentrations during these operations ranged from 0.120 to 1.840 mg/m(3), and median particle number concentrations from 4.8x10(4) to 5.4x10(5) particles/cm(3). Nanoparticles accounted for 40 to 95 % of particles, with Fe and Mn prevailing. Significant elevations were already seen in most oxidative stress markers and in several inflammation markers in the pre-shift samples relative to the controls. Significant associations were found between working in nanocomposite synthesis and the majority of EBC biomarkers. Chronic bronchitis was more frequent in researchers. A minor, but significant post-shift decrease of lung function parameters was found. We conclude that workers in nanocomposite synthesis may be at risk of developing airway disorders with time. From all the markers analyzed in EBC, the following markers were most robust and could be recommended for preventive examinations: 8-hydroxy-2-deoxyguanosine (8-OHdG) and 5-hydroxymethyl uracil (5-OHMeU) from nucleic acids, o-tyrosine (o-Tyr) and 3-nitrotyrosine (3-NOTyr) from proteins, and malondialdehyde and aldehydes C6-C13 from lipids. Among the markers of inflammation, tumor necrosis factor (TNF) and leukotriene B4 appeared to be the most useful.
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Optimalizace kultivačních podmínek lidských jaterních buněk HepG2 na 4 typech nano- a micro- vlákenných nosičů
Rössner ml., Pavel
Technologie popisuje optimalizaci počtu nasazovaných lidských hepatocytů HepG2, vhodných pro využívání v oblasti toxikologického ověřování nových léčiv či potravin, na 3D kultivační systém tvořený čtyřmi typy nano- a mikrovlákenných nosičů. Motivací pro hledání vhodných modelů testování potenciálně genotoxických účinků léčiv je nízká relevance tkáňových modelů užívaných v prvních fázích preklinického hodnocení nových látek a také redukce testování na zvířatech.
Modifikovaná metoda hodnocení mikrojader v lymfocytech s použitím hybridizace pancentrometrických fluorescenčně značených sond
Rössner ml., Pavel ; Rössnerová, Andrea
Tato metodika je založena na současném fluorescenčním barvení jak celých chromozomů, tak jejich centromer pomocí pancentrometrických sond. Díky tomu je možné vyhodnotit frekvenci mikrojader s / bez centromer, tedy určit rozdíly mezi strukturálními a numerickými aberacemi. Cílem metodiky bylo vytvořit inovativní postup pro vyhodnocení genotoxických účinků nanočástic, chemických látek včetně léků či záření na DNA živých organismů.
SIZE AS AN IMPORTANT FACTOR IN NANO-TiO2 TOXICITY IN MACROPHAGE-LIKE CELLS
Líbalová, Helena ; Sikorová, Jitka ; Brzicová, Táňa ; Milcová, Alena ; Vrbová, Kristýna ; Pikal, P. ; Topinka, Jan ; Rössner ml., Pavel
A set of NPs consists of 5 variants of anatase and 5 variants of rutile nanoparticles differing in their diameter (from 3 to 165 nm). TiO2 samples were characterized in the powder form and dispersed in water and cell culture media. Three cytotoxicity assays were used: MTS, WST-1, and LDH. For all nanomaterials, three independent repetitions were carried out. \n\nOverall, cytotoxicity of all NPs was low even at the highest concentration of 256 mu g/ml. The viability of cells did not decrease below 60% for WST-1 and MTS assays and 80% for the LDH assay. Besides concentration, crystalline size was identified as the most important cytotoxic factor. Clear nonlinear relationship between crystalline size and cytotoxicity was detected, higher toxicity induced NPs within the size range 20-60 nm. Increased cytotoxicity in given diameter size range would give an answer to inconsistent findings at size and cytotoxicity relationship.
GENOTOXICITY OF NANOMATERIALS IN BEAS-2B CELLS ANALYZED BY THE IN VITRO MICRONUCLEUS ASSAY
Rössnerová, Andrea ; Červená, Tereza ; Brzicová, Táňa ; Vrbová, Kristýna ; Sikorová, Jitka ; Topinka, Jan ; Rössner ml., Pavel
The tremendous increase of the use of nanomaterials (NMs) has been witnessed during the last decade in many areas of human life including the chemical industry, cosmetics, biomedicine or food technology. The variety of NMs, their unique properties, almost ubiquitous presence and the size range of 1-100 nm raised the interest of toxicologists. The evaluation of the frequency of micronuclei (MN) as a result of the genotoxic events is a broadly utilized and well-established approach in in vitro studies for testing the risk of chemical exposure. Nevertheless, properties of the NMs give rise to the questions concerning the optimal methodological variants of the MN assay. \n\nIn our study, five types of well-characterized NMs (TiO2: NM-101 and NM-103, SiO2: NM-200, Ag: NM-300K and NM-302) of specific size, shape, or e.g. dimensions of aggregates were involved in the genotoxicity testing using four variants of protocols differing in the time of NM exposure, application of cytochalasin-B combined with simultaneous and delayed co-treatment with nanoparticles (NPs). Bronchial epithelial cells (BEAS-2B) were used in this study to fulfil these tasks. Presence of NPs was controlled by transmission electron microscopy (TEM). \n\nObtained results showed the different genotoxic potential of the various TiO2 and Ag NMs (NM-101< NM-103 and NM-300K> NM-302, respectively). Comparison of all testing strategies revealed, that the level of DNA damage can differ based on the time of exposure and the methodological approach. In general, using cytochalasin-B led most frequently to the increase of the genotoxic potential of the tested NMs.
WHOLE-GENOME EXPRESSION ANALYSIS IN THP-1 MACROPHAGE-LIKE CELLS EXPOSED TO DIVERSE NANOMATERIALS
Brzicová, Táňa ; Líbalová, Helena ; Vrbová, Kristýna ; Sikorová, Jitka ; Philimonenko, Vlada ; Kléma, J. ; Topinka, Jan ; Rössner ml., Pavel
From the perspective of the immune system, nanomaterials (NMs) represent invading agents. Macrophages are immune cells residing in all organs and tissues as the first line of defense. Interactions of macrophages with NMs can determine the fate of NMs as well as their potential toxic effects. In the present study, we compared toxicity of four different types of NMs [NM-100 (TiO2, 110 nm), NM-110 (ZnO, 20 nm), NM-200 (SiO2, 150 nm) and NM-300K (Ag, 20 nm)], towards THP-1 macrophage-like cells. Cells were incubated with non-cytotoxic concentrations (1-25 mu g/ml) of NMs for 24 hours and microarray technology was used to analyze changes in whole-genome expression. Gene expression profiling revealed a substantially different molecular response following exposure to diverse NMs. While NM-100 did not exert any significant effect on gene expression profile, all other NMs triggered a pro-inflammatory response characterized by an activation of the NF-kappa B transcription factor and induced expression of numerous chemokines and cytokines. NM-110 and NM-300K further modulated processes such as DNA damage response, oxidative and replication stress as well as cell cycle progression and proteasome function. We suppose that genotoxicity of ZnO and Ag NMs leading to DNA damage and alternatively to apoptosis in THP-1 macrophages is probably caused by the extensive intracellular dissolution of these NPs, as confirmed by TEM imaging.

Národní úložiště šedé literatury : Nalezeno 11 záznamů.   1 - 10další  přejít na záznam:
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