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1.
In vitro hepatic 3D cell models and their application in genetic toxicology : a systematic review
Martina Štampar, Bojana Žegura, 2024, pregledni znanstveni članek

Povzetek: The rapid development of new chemicals and consumer products has raised concerns about their potential genotoxic effects on human health, including DNA damage leading to serious diseases. For such new chemicals and pharmaceutical products, international regulations require genotoxicity data, initially obtained through in vitro tests, followed by in vivo experiments, if needed. Traditionally, laboratory animals have been used for this purpose, however, they are costly, ethically problematic, and often unreliable due to species differences. Therefore, innovative more accurate in vitro testing approaches are rapidly being developed to replace, refine and reduce (3R) the use of animals for experimental purposes and to improve the relevance for humans in toxicology studies. One of such innovative approaches are in vitro three-dimensional (3D) cell models, which are already being highlighted as superior alternatives to the two-dimensional (2D) cell cultures that are traditionally used as in vitro models for the safety testing of chemicals and pharmaceuticals. 3D cell models provide physiologically relevant information and more predictive data for in vivo conditions. In the review article, we provide a comprehensive overview of 3D hepatic cell models, including HepG2, HepG2/C3A, HepaRG, human primary hepatocytes, and iPSC-derived hepatocytes, and their application in the field of genotoxicology. Through a detailed literature analysis, we identified 31 studies conducted between 2007 and April 2024 that used a variety of standard methods, such as the comet assay, the micronucleus assay, and the γH2AX assay, as well as new methodological approaches, including toxicogenomics, to assess the cytotoxic and genotoxic activity of chemicals, nanoparticles and natural toxins. Based on our search, we can conclude that the use of in vitro 3D cell models for genotoxicity testing has been increasing over the years and that 3D cell models have an even greater potential for future implementation and further refinement in genetic toxicology and risk assessment.
Ključne besede: genotoxicity, advanced 3D in vitro models, hepatic cells, spheroids, comet assay, micronucleus assay, genotoxicology, toxicological studies
Objavljeno v DiRROS: 14.11.2024; Ogledov: 120; Prenosov: 59
.pdf Celotno besedilo (1,32 MB)
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2.
Impact of indoor air pollution on DNA damage and chromosome stability : a systematic review
Luka Kazensky, Katarina Matković, Marko Gerić, Bojana Žegura, Gordana Pehnec, Goran Gajski, 2024, pregledni znanstveni članek

Povzetek: Indoor air pollution is becoming a rising public health problem and is largely resulting from the burning of solid fuels and heating in households. Burning these fuels produces harmful compounds, such as particulate matter regarded as a major health risk, particularly affecting the onset and exacerbation of respiratory diseases. As exposure to polluted indoor air can cause DNA damage including DNA sd breaks as well as chromosomal damage, in this paper, we aim to provide an overview of the impact of indoor air pollution on DNA damage and genome stability by reviewing the scientific papers that have used the comet, micronucleus, and γ-H2AX assays. These methods are valuable tools in human biomonitoring and for studying the mechanisms of action of various pollutants, and are readily used for the assessment of primary DNA damage and genome instability induced by air pollutants by measuring different aspects of DNA and chromosomal damage. Based on our search, in selected studies (in vitro, animal models, and human biomonitoring), we found generally higher levels of DNA strand breaks and chromosomal damage due to indoor air pollutants compared to matched control or unexposed groups. In summary, our systematic review reveals the importance of the comet, micronucleus, and γ-H2AX assays as sensitive tools for the evaluation of DNA and genome damaging potential of different indoor air pollutants. Additionally, research in this particular direction is warranted since little is still known about the level of indoor air pollution in households or public buildings and its impact on genetic material. Future studies should focus on research investigating the possible impact of indoor air pollutants in complex mixtures on the genome and relate pollutants to possible health outcomes.
Ključne besede: indoor air quality, genome damage, comet assay, micronucleus assay, γ-H2AX assay, health risk
Objavljeno v DiRROS: 06.11.2024; Ogledov: 98; Prenosov: 53
.pdf Celotno besedilo (825,18 KB)
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3.
Evidence driven indoor air quality improvement : an innovative and interdisciplinary approach to improving indoor air quality
Mario Lovrić, Goran Gajski, Jessica Fernández-Agüera, Mira Pöhlker, Bojana Žegura, Matjaž Novak, Alja Štern, Katja Kološa, Martina Štampar, 2024, pregledni znanstveni članek

Povzetek: Indoor air pollution is a recognized emerging threat, claiming millions of lives annually. People are constantly exposed to ambient and indoor air pollution. The latest research shows that people in developed countries spend up to 90% of their time indoors and almost 70% at home. Although impaired IAQ represents a significant health risk, it affects people differently, and specific populations are more vulnerable: children, the elderly, and people with respiratory illnesses are more sensitive to these environmental risks. Despite rather extensive research on IAQ, most of the current understanding about the subject, which includes pollution sources, indoor–outdoor relationships, and ventilation/filtration, is still quite limited, mainly because air quality monitoring in the EU is primarily focused on ambient air quality and regulatory requirements are lacking for indoor environments. Therefore, the EDIAQI project aims to improve guidelines and awareness for advancing the IAQ in Europe and beyond by allowing user-friendly access to information about indoor air pollution exposures, sources, and related risk factors. The solution proposed with EDIAQI consists of conducting a characterization of sources and routes of exposure and dispersion of chemical, biological, and emerging indoor air pollution in multiple cities in the EU. The project will deploy cost-effective/user-friendly monitoring solutions to create new knowledge on sources, exposure routes, and indoor multipollutant body burdens. The EDIAQI project brings together 18 organizations from 11 different European countries that provide interdisciplinary skills and expertise in various fields, including environmental science and technology, medicine, and toxicology, as well as policy design and public engagement.
Ključne besede: indoor air pollution, health risk, vulnerable populations, IAQ (Indoor Air Quality), EDIAQI project, monitoring solutions, exposure routes
Objavljeno v DiRROS: 06.11.2024; Ogledov: 109; Prenosov: 70
.pdf Celotno besedilo (2,15 MB)
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4.
Hazard characterization of Alternaria toxins to identify data gaps and improve risk assessment for human health
Henriqueta Louro, Ariane Vettorazzi, Adela López de Cerain, Bojana Žegura, Matjaž Novak, 2024, pregledni znanstveni članek

Povzetek: Fungi of the genus Alternaria are ubiquitous plant pathogens and saprophytes which are able to grow under varying temperature and moisture conditions as well as on a large range of substrates. A spectrum of structurally diverse secondary metabolites with toxic potential has been identified, but occurrence and relative proportion of the different metabolites in complex mixtures depend on strain, substrate, and growth conditions. This review compiles the available knowledge on hazard identification and characterization of Alternaria toxins. Alternariol (AOH), its monomethylether AME and the perylene quinones altertoxin I (ATX-I), ATX-II, ATX-III, alterperylenol (ALP), and stemphyltoxin III (STTX-III) showed in vitro genotoxic and mutagenic properties. Of all identified Alternaria toxins, the epoxide-bearing analogs ATX-II, ATX-III, and STTX-III show the highest cytotoxic, genotoxic, and mutagenic potential in vitro. Under hormone-sensitive conditions, AOH and AME act as moderate xenoestrogens, but in silico modeling predicts further Alternaria toxins as potential estrogenic factors. Recent studies indicate also an immunosuppressive role of AOH and ATX-II; however, no data are available for the majority of Alternaria toxins. Overall, hazard characterization of Alternaria toxins focused, so far, primarily on the commercially available dibenzo-α-pyrones AOH and AME and tenuazonic acid (TeA). Limited data sets are available for altersetin (ALS), altenuene (ALT), and tentoxin (TEN). The occurrence and toxicological relevance of perylene quinone-based Alternaria toxins still remain to be fully elucidated. We identified data gaps on hazard identification and characterization crucial to improve risk assessment of Alternaria mycotoxins for consumers and occupationally exposed workers.
Ključne besede: mycotoxin, exposure routes, genotoxicity, endocrine disruption, immunosuppression, biotransformation, toxicokinetics, tenuazonic acid, alternariol, altenuene, tentoxin, altertoxin
Objavljeno v DiRROS: 07.08.2024; Ogledov: 288; Prenosov: 239
.pdf Celotno besedilo (3,22 MB)
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5.
Synthesis, purification, and cell-toxicity of a choline betainate
Lucija Jurko, Gregor Hostnik, Tobias Alexander Steindorfer, Alja Štern, Perica Bošković, Matej Bračič, Bojana Žegura, Rupert Kargl, 2024, izvirni znanstveni članek

Povzetek: In this work, choline chloride and betaine hydrochloride were condensed into a - to our knowledge - unreported choline betainate (N,N,N-trimethyl-2-oxo-2-(2-(trimethylammonio)ethoxy)ethanaminium chloride) using 1,1′-carbonyldiimidazole (CDI) activation of betaine hydrochloride in dimethylsulfoxide. The product and reaction intermediates were isolated, purified by preparative HPLC and analyzed in detail by infrared and nuclear magnetic resonance spectroscopy. The final product has a high cytotoxicity for L929 mouse fibroblasts, and low antibacterial activity against P. Aeruginosa and S. Aureus at concentrations of up to 20 mg/ml. It could potentially further be investigated for similar uses as suxamethonium chloride, a muscle relaxant drug.
Ključne besede: choline chloride, betaine hydrochloride, carbonyldiimidazole, HPLC, antimicrobial, cytotoxicity
Objavljeno v DiRROS: 07.08.2024; Ogledov: 302; Prenosov: 339
.pdf Celotno besedilo (3,60 MB)
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6.
New approach methodologies to facilitate and improve the hazard assessment of non-genotoxic carcinogens : a PARC project
Marc Audebert, Ann-Sophie Assmann, Amaya Azqueta, Pavel Babica, Emilio Benfenati, Martina Štampar, Bojana Žegura, 2023, pregledni znanstveni članek

Povzetek: Carcinogenic chemicals, or their metabolites, can be classified as genotoxic or non-genotoxic carcinogens (NGTxCs). Genotoxic compounds induce DNA damage, which can be detected by an established in vitro and in vivo battery of genotoxicity assays. For NGTxCs, DNA is not the primary target, and the possible modes of action (MoA) of NGTxCs are much more diverse than those of genotoxic compounds, and there is no specific in vitro assay for detecting NGTxCs. Therefore, the evaluation of the carcinogenic potential is still dependent on long-term studies in rodents. This 2-year bioassay, mainly applied for testing agrochemicals and pharmaceuticals, is time-consuming, costly and requires very high numbers of animals. More importantly, its relevance for human risk assessment is questionable due to the limited predictivity for human cancer risk, especially with regard to NGTxCs. Thus, there is an urgent need for a transition to new approach methodologies (NAMs), integrating human-relevant in vitro assays and in silico tools that better exploit the current knowledge of the multiple processes involved in carcinogenesis into a modern safety assessment toolbox. Here, we describe an integrative project that aims to use a variety of novel approaches to detect the carcinogenic potential of NGTxCs based on different mechanisms and pathways involved in carcinogenesis. The aim of this project is to contribute suitable assays for the safety assessment toolbox for an efficient and improved, internationally recognized hazard assessment of NGTxCs, and ultimately to contribute to reliable mechanism-based next-generation risk assessment for chemical carcinogens.
Ključne besede: non-genotoxic carcinogens, NGTxC, new approach methodologies, NAM, PARC
Objavljeno v DiRROS: 05.08.2024; Ogledov: 262; Prenosov: 140
.pdf Celotno besedilo (761,23 KB)
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7.
Double strand breaks and cell-cycle arrest induced by the cyanobacterial toxin cylindrospermopsin in HepG2 cells
Alja Štern, Metka Filipič, Matjaž Novak, Bojana Žegura, 2013, izvirni znanstveni članek

Povzetek: The newly emerging cyanobacterial cytotoxin cylindrospermopsin (CYN) is increasingly found in surface freshwaters, worldwide. It poses a potential threat to humans after chronic exposure as it was shown to be genotoxic in a range of test systems and is potentially carcinogenic. However, the mechanisms of CYN toxicity and genotoxicity are not well understood. In the present study CYN induced formation of DNA double strand breaks (DSBs), after prolonged exposure (72 h), in human hepatoma cells, HepG2. CYN (0.1–0.5 µg/mL, 24–96 h) induced morphological changes and reduced cell viability in a dose and time dependent manner. No significant increase in lactate dehydrogenase (LDH) leakage could be observed after CYN exposure, indicating that the reduction in cell number was due to decreased cell proliferation and not due to cytotoxicity. This was confirmed by imunocytochemical analysis of the cell-proliferation marker Ki67. Analysis of the cell-cycle using flow-cytometry showed that CYN has an impact on the cell cycle, indicating G0/G1 arrest after 24 h and S-phase arrest after longer exposure (72 and 96 h). Our results provide new evidence that CYN is a direct acting genotoxin, causing DSBs, and these facts need to be considered in the human health risk assessment.
Ključne besede: cylindrospermopsin, cell-cycle, cell-proliferation, double-strand breaks, HepG2 cells
Objavljeno v DiRROS: 02.08.2024; Ogledov: 338; Prenosov: 235
.pdf Celotno besedilo (689,29 KB)
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8.
DNAqua-Net : developing new genetic tools for bioassessment and monitoring of aquatic ecosystems in Europe
Florian Leese, Tina Eleršek, Cene Fišer, Ana Rotter, Bojana Žegura, Irena Maček, 2016, izvirni znanstveni članek

Povzetek: The protection, preservation and restoration of aquatic ecosystems and their functions are of global importance. For European states it became legally binding mainly through the EU-Water Framework Directive (WFD). In order to assess the ecological status of a given water body, aquatic biodiversity data are obtained and compared to a reference water body. The quantified mismatch obtained determines the extent of potential management actions. The current approach to biodiversity assessment is based on morpho-taxonomy. This approach has many drawbacks such as being time consuming, limited in temporal and spatial resolution, and error-prone due to the varying individual taxonomic expertise of the analysts. Novel genomic tools can overcome many of the aforementioned problems and could complement or even replace traditional bioassessment. Yet, a plethora of approaches are independently developed in different institutions, thereby hampering any concerted routine application. The goal of this Action is to nucleate a group of researchers across disciplines with the task to identify gold-standard genomic tools and novel eco-genomic indices for routine application in biodiversity assessments of European fresh- and marine water bodies. Furthermore, DNAqua-Net will provide a platform for training of the next generation of European researchers preparing them for the new technologies. Jointly with water managers, politicians, and other stakeholders, the group will develop a conceptual framework for the standard application of eco-genomic tools as part of legally binding assessments.
Ključne besede: aquatic ecosystems, biodiversity, monitoring, genomic tools
Objavljeno v DiRROS: 25.07.2024; Ogledov: 288; Prenosov: 135
.pdf Celotno besedilo (361,20 KB)
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9.
Use of HuH6 and other human-derived hepatoma lines for the detection of genotoxins : a new hope for laboratory animals?
Monika Waldherr, Miroslav Mišík, Franziska Ferk, Jana Tomc, Bojana Žegura, Metka Filipič, Wolfgang Mikulits, Sören Mai, Oskar Haas, Wolfgang W. Huber, Elisabeth Haslinger, Siegfried Knasmüller, 2018, izvirni znanstveni članek

Povzetek: Cell lines which are currently used in genotoxicity tests lack enzymes which activate/detoxify mutagens. Therefore, rodent-derived liver preparations are used which reflect their metabolism in humans only partly; as a consequence misleading results are often obtained. Previous findings suggest that certain liver cell lines express phase I/II enzymes and detect promutagens without activation; however, their use is hampered by different shortcomings. The aim of this study was the identification of a suitable cell line. The sensitivity of twelve hepatic cell lines was investigated in single cell gel electrophoresis assays. Furthermore, characteristics of these lines were studied which are relevant for their use in genotoxicity assays (mitotic activity, p53 status, chromosome number, and stability). Three lines (HuH6, HCC1.2, and HepG2) detected representatives of five classes of promutagens, namely, IQ and PhIP (HAAs), B(a)P (PAH), NDMA (nitrosamine), and AFB1 (aflatoxin), and were sensitive towards reactive oxygen species (ROS). In contrast, the commercially available line HepaRG, postulated to be a surrogate for hepatocytes and an ideal tool for mutagenicity tests, did not detect IQ and was relatively insensitive towards ROS. All other lines failed to detect two or more compounds. HCC1.2 cells have a high and unstable chromosome number and mutated p53, these features distract from its use in routine screening. HepG2 was frequently employed in earlier studies, but pronounced inter-laboratory variations were observed. HuH6 was never used in genotoxicity experiments and is highly promising, it has a stable karyotype and we demonstrated that the results of genotoxicity experiments are reproducible.
Ključne besede: hepatic cell lines, p53, comet assay, genotoxicity
Objavljeno v DiRROS: 24.07.2024; Ogledov: 298; Prenosov: 195
.pdf Celotno besedilo (1,18 MB)
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10.
Genotoxic effects of cylindrospermopsin, microcystin-LR and their binary mixture in human hepatocellular carcinoma (HepG2) cell line
Leticia Díez-Quijada, Klara Hercog, Martina Štampar, Metka Filipič, Ana M. Cameán, Angeles Jos, Bojana Žegura, 2020, izvirni znanstveni članek

Povzetek: Simultaneous occurrence of cylindrospermopsin (CYN) and microcystin-LR (MCLR) has been reported in the aquatic environment and thus human exposure to such mixtures is possible. As data on the combined effects of CYN/MCLR are scarce, we aimed to investigate the adverse effects related to genotoxic activities induced by CYN (0.125, 0.25 and 0.5 µg/mL) and MCLR (1 µg/mL) as single compounds and their combinations in HepG2 cells after 24 and 72 h exposure. CYN and CYN/MCLR induced DNA double-strand breaks after 72 h exposure, while cell cycle analysis revealed that CYN and CYN/MCLR arrested HepG2 cells in G0/G1 phase. Moreover, CYN and the combination with MCLR upregulated CYP1A1 and target genes involved in DNA-damage response (CDKN1A, GADD45A). Altogether, the results showed that after 72 h exposure genotoxic activity of CYN/MCLR mixture was comparable to the one of pure CYN. On the contrary, MCLR (1 µg/mL) had no effect on the viability of cells and had no influence on cell division. It did not induce DNA damage and did not deregulate studied genes after prolonged exposure. The outcomes of the study confirm the importance of investigating the combined effects of several toxins as the effects can differ from those induced by single compounds.
Objavljeno v DiRROS: 23.07.2024; Ogledov: 267; Prenosov: 208
.pdf Celotno besedilo (1,68 MB)
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