26 results on '"Liszewska M"'
Search Results
2. Raman scattering of low energy HgCdTe phonons
- Author
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Grodecki, K., primary, Sobieski, J., additional, Majkowycz, K., additional, Madejczyk, P., additional, Jankiewicz, B., additional, Liszewska, M., additional, and Martyniuk, P., additional
- Published
- 2022
- Full Text
- View/download PDF
3. Silver nanoparticles in titanium dioxide host plasmonic absorbers
- Author
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Nyga, P., primary, Chmiel, S., additional, Szczurek, M., additional, Liszewska, M., additional, Stefaniak, M., additional, Firak, J., additional, Michalska-Domanska, M., additional, Mierczyk, J., additional, and Norek, M., additional
- Published
- 2016
- Full Text
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4. Endocrine-disrupting chemicals - pesticide regulatory issues from the EU perspective.
- Author
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Liszewska M, Czaja K, Korcz W, Lewiński R, and Struciński P
- Abstract
Endocrine-disrupting chemicals (EDCs), including substances used in plant protection products (PPPs), are a source of ongoing concern for the EU society. Under the EC Regulation 1107/2009, the endocrine-disrupting (ED) properties of active substances, safeners, and synergists used in PPPs shall be investigated. The scientific criteria established by the Regulation (EU) 2018/605 and the joint guidance of the European Chemicals Agency (ECHA)/European Food Safety Authority (EFSA) provide the basis for this assessment. Data requirements for the approval of safeners and synergists have been recently published in Commission Regulation (EU) 2024/1487, allowing a consistent assessment of these substances. The approach to assessing co-formulant hazards is currently a subject of EU-wide discussion. It outlines the necessity to take into account information or evaluation data from other than pesticides' EU regulatory frameworks, such as REACH or SCCS applications for cosmetic ingredients. This paper outlines: a) current EU approach applied for identification of endocrine disrupting properties of pesticides; b) issues related to European regulations that may have an indirect impact on the safe use of plant protection products and c) an analysis of the European Commission's activities aimed to limit exposure to EDCs associated with use of PPPs in the society., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)
- Published
- 2024
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5. Decabromodifenyl Ether (BDE-209) in Surface Soils from Warsaw and Surrounding Areas: Characterization of Non-Carcinogenic Risk Associated with Oral and Dermal Exposure.
- Author
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Korcz W, Czaja K, Liszewska M, Lewiński R, Słomczyńska A, and Struciński P
- Subjects
- Humans, Poland, Environmental Monitoring methods, Environmental Exposure analysis, Flame Retardants analysis, Risk Assessment, Administration, Oral, Halogenated Diphenyl Ethers analysis, Soil Pollutants analysis, Soil chemistry
- Abstract
Polybrominated diphenyl ethers (PBDEs) have been used for many years as flame retardants. Due to their physicochemical and toxicological properties, they are considered to be persistent organic pollutants (POPs). BDE-209 is the main component of deca-BDE, the one PBDE commercial mixture currently approved for use in the European Union. The aim of this study was to analyse BDE-209 in surface soil samples from Warsaw and surrounding areas (Poland) as an indicator of environmental pollution with PBDEs, and to characterise the associated health risk. A total of 40 samples were analysed using gas chromatography with electron capture detection (GC-µECD). Concentrations of BDE-209 in soil ranged from 0.4 ng g
-1 d.w. (limit of quantification) to 158 ng g-1 d.w. Overall, 52.5% of results were above the method's limit of quantification. The highest levels were found at several locations with heavy traffic and in the vicinity of a CHP plant in the city. The lowest concentrations were observed in most of the samples collected from low industrialized or green areas (<0.4 to 1.68 ng g-1 d.w.). Exposure to BDE-209 was estimated for one of the most sensitive populations, i.e., young children. The following exposure routes were selected: oral and dermal. No risk was found to young children's health.- Published
- 2024
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6. Evaluation of adhesion strength, corrosion, and biological properties of the MWCNT/TiO 2 coating intended for medical applications.
- Author
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Rogala-Wielgus D, Majkowska-Marzec B, Zieliński A, Roszek K, and Liszewska M
- Abstract
Multi-wall carbon nanotube (MWCNT) coatings are gaining increasing interest because of their special properties used in many science fields. The titania coatings are known for their improvement of osteoblast adhesion, thus changing the surface architecture. Bi-layer coatings comprising 0.25 wt% of the MWCNTs and 0.30 wt% of titania (anatase structure) were synthesized in a two-stage procedure using the electrophoretic deposition method (EPD). The MWCNT and TiO
2 coatings were deposited with voltage and time parameters, respectively, of 20 V and 0.5 min, and 50 V and 4 min. EDS, AFM, SEM, Raman spectroscopy, nano-scratch test, potentiodynamic corrosion tests, wettability studies, and cytotoxicity determined with MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test on human dermal fibroblasts (HDF) and mouse osteoblast precursors (MC3T3), and lactate dehydrogenase (LDH) activity test were carried out on examined surfaces. The prepared MWCNT/TiO2 coating is uniformly distributed by MWCNTs and agglomerated by TiO2 particles of size ranging from 0.1 to 3 μm. Raman spectroscopy confirmed the anatase structure of the TiO2 addition and showed typical peaks of the MWCNTs. The MWCNT/TiO2 coating had higher roughness, higher adhesion strength, and improved corrosion resistance compared to the MWCNT basic coating. The results of biological tests proved that physicochemical properties of the surface, such as high porosity and wettability of MWCNT/TiO2 -coated material, would support cell adhesion, but toxic species could be released to the culture medium, thus resulting in a decrease in proliferation., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2023
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7. Assessment of Furan and Its Derivatives Intake with Home Prepared Meals and Characterization of Associated Risk for Polish Infants and Toddlers.
- Author
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Minorczyk M, Czaja K, Starski A, Korcz W, Liszewska M, Lewiński R, Robson MG, Postupolski J, and Struciński P
- Abstract
Furan and its derivatives are found in various heat-treated foods. Furan is classified as a possible human carcinogen. The European Union authorities recommend collecting data on the occurrence of these compounds, estimating consumer exposure, and taking measures to protect human health based on a scientific risk assessment. The aim of this study was to estimate the exposure of infants and toddlers to furan and its methyl derivatives-2-methylfuran, 3-methylfuran, and ∑2,5-dimethylfuran/2-ethylfuran-present in home-prepared foods and to characterize the associated health risks. The compounds of interest were determined using the HS-GC/MS. The risk was characterized by the calculation of the margin of exposure (MoE). Levels of furan and its derivatives in analyzed samples were in the range of
- Published
- 2023
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8. α-Amino Acids as Reducing and Capping Agents in Gold Nanoparticles Synthesis Using the Turkevich Method.
- Author
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Figat AM, Bartosewicz B, Liszewska M, Budner B, Norek M, and Jankiewicz BJ
- Abstract
Amino acid-capped gold nanoparticles (AuNPs) are a promising tool for various applications, including therapeutics and diagnostics. Most often, amino acids are used to cap AuNPs synthesized with other reducing agents. However, only a few studies have been dedicated to using α-amino acids as reducing and capping agents in AuNPs synthesis. Hence, there are still several gaps in understanding their role in reducing gold salts. Here, we used 20 proteinogenic α-amino acids and one non-proteinogenic α-amino acid in analogy to sodium citrate as reducing and capping agents in synthesizing AuNPs using the Turkevich method. Only four of the twenty-one investigated amino acids have not yielded gold nanoparticles. The shape, size distribution, stability, and optical properties of synthesized nanoparticles were characterized by scanning electron microscopy, differential centrifugal sedimentation, the phase analysis light scattering technique, and UV-vis spectroscopy. The physicochemical characteristics of synthesized AuNPs varied with the amino acid used for the reduction. We proposed that in the initial stage of gold salts reduction most of the used α-amino acids behave similarly to citrate in the Turkevich method. However, their different physicochemical properties resulting from differences in their chemical structures significantly influence the outcomes of reactions.
- Published
- 2023
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9. SERS performance of GaN/Ag substrates fabricated by Ag coating of GaN platforms.
- Author
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Zając MA, Budner B, Liszewska M, Bartosewicz B, Gutowski Ł, Weyher JL, and Jankiewicz BJ
- Abstract
The results of comparative studies on the fabrication and characterization of GaN/Ag substrates using pulsed laser deposition (PLD) and magnetron sputtering (MS) and their evaluation as potential substrates for surface-enhanced Raman spectroscopy (SERS) are reported. Ag layers of comparable thicknesses were deposited using PLD and MS on nanostructured GaN platforms. All fabricated SERS substrates were examined regarding their optical properties using UV-vis spectroscopy and regarding their morphology using scanning electron microscopy. SERS properties of the fabricated GaN/Ag substrates were evaluated by measuring SERS spectra of 4-mercaptobenzoic acid molecules adsorbed on them. For all PLD-made GaN/Ag substrates, the estimated enhancement factors were higher than for MS-made substrates with a comparable thickness of the Ag layer. In the best case, the PLD-made GaN/Ag substrate exhibited an approximately 4.4 times higher enhancement factor than the best MS-made substrate., (Copyright © 2023, Zając et al.)
- Published
- 2023
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10. Validation of a Modified QuEChERS Method for the Determination of Selected Organochlorine Compounds in Honey.
- Author
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Lewiński R, Hernik A, Liszewska M, Buckley B, Czaja K, Korcz W, Słomczyńska A, and Struciński P
- Subjects
- DDT chemistry, Dichlorodiphenyl Dichloroethylene analysis, Dieldrin analysis, Reproducibility of Results, Heptachlor analysis, Honey analysis, Hydrocarbons, Chlorinated chemistry, Pesticides analysis
- Abstract
Honey is considered to be a health-promoting food product. Therefore, it is assumed that it should be free of contaminants. Although the use of organochlorine pesticides (OCPs) was banned a few decades ago in developed countries, persistent organic pollutants (POPs) are still detected in various environmental and biological matrices, including food. These contaminants exhibit toxic properties and bioaccumulate in some food chains. The validation of a modified QuEChERS extraction method was successfully performed for o,p' -DDT, o,p' -DDE, o,p' -DDD, p,p' -DDT, p,p' -DDE, p,p' -DDD, heptachlor and dieldrin. 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153) was used as an internal standard. The modification involved changing the solvent from acetonitrile to n-hexane after extraction. Quantitation was carried out using gas chromatography with an electron capture detector (µECD). The mean recovery values for o,p' -DDT, o,p' -DDE, o,p' -DDD, p,p' -DDT, p,p' -DDE, p,p' -DDD and dieldrin, spiked at 2.9 ng/g and 20 ng/g, ranged from 64.7% to 129.3%, and, for heptachlor spiked at 5.6 ng/g and 20 ng/g, ranged from 68.0% to 88.3%. The relative standard deviation (RSD) for these concentrations did not exceed 20%, and the within-laboratory reproducibility was below 20%, except o,p' -DDE and p,p' -DDT, which were 25.2% and 20.7%, respectively. This modified QuEChERS extraction method for selected organochlorine compounds was demonstrated as effective for routine testing in honey.
- Published
- 2023
- Full Text
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11. Investigation of organic monoradicals reactivity using surface-enhanced Raman spectroscopy.
- Author
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Gutowski Ł, Liszewska M, Bartosewicz B, Budner B, Weyher JL, and Jankiewicz BJ
- Abstract
Surface-enhanced Raman spectroscopy (SERS) and self-assembled monolayer (SAM) approaches were used to investigate the reactions of organic monoradicals with methanol. An attempt was made to generate monoradicals from thiophenols and phenylmethanethiols substituted with bromine, iodine, and nitro groups by irradiation with UV light. Monolayers of radical precursors were deposited on SERS substrates, which were then immersed in methanol and irradiated for 1 and/or 3, 6, 12 and 24 h in a UV photochemical reactor. Pre- and postreaction SERS spectra were obtained by using a confocal Raman microscope and compared with the spectra of expected products of the radical reaction with methanol. Our studies have shown that the efficiency of monoradical generation is highly dependent on the chemical structure of the precursor. In addition, it is shown that both the SERS substrate and experimental conditions used strongly influence the obtained results., (Copyright © 2022 The Author(s). Published by Elsevier B.V. All rights reserved.)
- Published
- 2022
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12. The Multi-Gas Sensor for Remote UAV and UGV Missions-Development and Tests.
- Author
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Kaliszewski M, Włodarski M, Młyńczak J, Jankiewicz B, Auer L, Bartosewicz B, Liszewska M, Budner B, Szala M, Schneider B, Povoden G, and Kopczyński K
- Abstract
In this article, we present a versatile gas detector that can operate on an unmanned aerial vehicle (UAV) or unmanned ground vehicle (UGV). The device has six electrochemical modules, which can be selected to measure specific gases, according to the mission requirements. The gas intake is realized by a miniaturized vacuum pump, which provides immediate gas distribution to the sensors and improves a fast response. The measurement data are sent wirelessly to the operator's computer, which continuously stores results and presents them in real time. The 2 m tubing allows measurements to be taken in places that are not directly accessible to the UGV or the UAV. While UAVs significantly enhanced the versatility of sensing applications, point gas detection is challenging due to the downwash effect and gas dilution produced by the rotors. In our work, we demonstrated the method of downwash effect reduction at aerial point gas measurements by applying a long-distance probe, which was kept between the UAV and the examined object. Moreover, we developed a safety connection protecting the UAV and sensor in case of accidental jamming of the tubing inside the examined cavity. The methods presented provide an effective gas metering strategy using UAVs.
- Published
- 2021
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13. Analysis of the Morphology and Structure of Carbon Deposit Formed on the Surface of Ni 3 Al Foils as a Result of Thermocatalytic Decomposition of Ethanol.
- Author
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Jóźwik P, Baran A, Płociński T, Dziedzic D, Nawała J, Liszewska M, Zasada D, and Bojar Z
- Abstract
This article presents the results of investigations of the morphology and structure of carbon deposit formed as a result of ethanol decomposition at 500 °C, 600 °C, and 700 °C without water vapour and with water vapour (0.35 and 1.1% by volume). scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM) observations as well as energy dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD), and Raman spectroscopic analyses allowed for a comprehensive characterization of the morphology and structure of cylindrical carbon nanostructures present on the surface of the Ni
3 Al catalyst. Depending on the reaction mixture composition (i.e., water vapour content) and decomposition temperature, various carbon nanotubes/carbon nanofibres (CNTs/CNFs) were observed: multiwalled carbon nanotubes, herringbone-type multiwall carbon nanotubes, cylindrical carbon nanofibers, platelet carbon nanofibers, and helical carbon nanotubes/nanofibres. The discussed carbon nanostructures exhibited nickel nanoparticles at the ends and in the middle part of the carbon nanostructures as catalytically active centres for efficient ethanol decomposition.- Published
- 2021
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14. Fabrication of Ag-modified hollow titania spheres via controlled silver diffusion in Ag-TiO 2 core-shell nanostructures.
- Author
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Bartosewicz B, Liszewska M, Budner B, Michalska-Domańska M, Kopczyński K, and Jankiewicz BJ
- Abstract
Inorganic hollow spheres find a growing number of applications in many fields, including catalysis and solar cells. Hence, a simple fabrication method with a low number of simple steps is desired, which would allow for good control over the structural features and physicochemical properties of titania hollow spheres modified with noble metal nanoparticles. A simple method employing sol-gel coating of nanoparticles with titania followed by controlled silver diffusion was developed and applied for the synthesis of Ag-modified hollow TiO
2 spheres. The morphology of the synthesized structures and their chemical composition was investigated using SEM and X-ray photoelectron spectroscopy, respectively. The optical properties of the synthesized structures were characterized using UV-vis spectroscopy. Ag-TiO2 hollow nanostructures with different optical properties were prepared simply by a change of the annealing time in the last fabrication step. The synthesized nanostructures exhibit a broadband optical absorption in the UV-vis range., (Copyright © 2020, Bartosewicz et al.; licensee Beilstein-Institut.)- Published
- 2020
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15. Revisiting semicontinuous silver films as surface-enhanced Raman spectroscopy substrates.
- Author
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Liszewska M, Budner B, Norek M, Jankiewicz BJ, and Nyga P
- Abstract
Surface-enhanced Raman spectroscopy (SERS) is a very promising analytical technique for the detection and identification of trace amounts of analytes. Among the many substrates used in SERS of great interest are nanostructures fabricated using physical methods, such as semicontinuous metal films obtained via electron beam physical vapor deposition. In these studies, we investigate the influence of morphology of semicontinuous silver films on their SERS properties. The morphologies studied ranged from isolated particles through percolated films to almost continuous films. We found that films below the percolation threshold (transition from dielectric-like to metal-like) made of isolated silver structures provided the largest SERS enhancement of 4-aminothiophenol (4-ATP) analyte signals. The substrate closest to the percolation threshold has the SERS signal about four times lower than the highest signal sample.
- Published
- 2019
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16. Fabrication of silver nanoisland films by pulsed laser deposition for surface-enhanced Raman spectroscopy.
- Author
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Budner B, Kuźma M, Nasiłowska B, Bartosewicz B, Liszewska M, and Jankiewicz BJ
- Abstract
The results of studies on the fabrication and characterization of silver nanoisland films (SNIFs) using pulsed laser deposition (PLD) and the evaluation of these films as potential surface-enhanced Raman scattering (SERS) substrates are reported. The SNIFs with thicknesses in a range of 4.7 ± 0.2 nm to 143.2 ± 0.2 nm were deposited under different conditions on silicon substrates. Size and morphology of the fabricated silver nanoislands mainly depend on the substrate temperature, and number and energy of the laser pulses. SERS properties of the fabricated films were evaluated by measuring SERS spectra of para -mercaptoaniline (pMA) molecules adsorbed on them. SERS enhancement factors are shown to depend on the SNIF morphology, which is modified by changes of the deposition conditions. The highest enhancement factor in the range of 10
5 was achieved for SNIFs that have oval and circular silver nanoislands with small distances between them.- Published
- 2019
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17. Hypomethylation of the c-myc promoter region induced by phenobarbital in rat liver
- Author
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Urbanek-Olejnik K, Liszewska M, Winczura A, Hernik A, Strucinski P, and Ludwicki JK
- Subjects
- Animals, Dose-Response Relationship, Drug, Male, Rats, Rats, Wistar, DNA Methylation, Liver drug effects, Phenobarbital toxicity, Promoter Regions, Genetic drug effects, Proto-Oncogene Proteins c-myc metabolism
- Abstract
Background: The changes in DNA methylation are considered as one of the early events in hepatocarcinogenesis., Objective: We evaluated the ability of phenobarbital (PB) – the most widely used anticonvulsant worldwide and classical rodent liver carcinogen – to cause the promoter region of the c-myc protooncogene hypomethylation as well as changes of mRNA level of this gene. Moreover, the expression of Dnmt1 protein in rat treated with this compound was analyzed., Material and Methods: Male Wistar rats received PB in daily oral doses of 92.8 mg kg-1 b.w. day-1 (at 24-h intervals; for one, three and fourteen days). Methylation of the c-myc promoter region was measured by PCR-based methylationsensitive restriction enzyme analysis (MSRA). Levels of mRNA for c-myc and protein Dnmt1 were assayed using Real-Time PCR and Western Blot, respectively., Results: The study showed that phenobarbital stimulated persistent changes in DNA methylation, i.e. loss of methylation in the promoter region of the c-myc gene and up-regulated its mRNA level. In addition, a significant increase in protein level of Dnmt1 in the c-myc over-expressing liver cells was observed., Conclusion: The oppose relationship between Dnmt1 activity and methylation status of c-myc gene was demonstrated. The c-myc over-expression by demethylation might represent an important, early events in the mechanism of action (MOA) of phenobarbital.
- Published
- 2018
18. Synthesis and characterization of noble metal-titania core-shell nanostructures with tunable shell thickness.
- Author
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Bartosewicz B, Michalska-Domańska M, Liszewska M, Zasada D, and Jankiewicz BJ
- Abstract
Core-shell nanostructures have found applications in many fields, including surface enhanced spectroscopy, catalysis and solar cells. Titania-coated noble metal nanoparticles, which combine the surface plasmon resonance properties of the core and the photoactivity of the shell, have great potential for these applications. However, the controllable synthesis of such nanostructures remains a challenge due to the high reactivity of titania precursors. Hence, a simple titania coating method that would allow better control over the shell formation is desired. A sol-gel based titania coating method, which allows control over the shell thickness, was developed and applied to the synthesis of Ag@TiO
2 and Au@TiO2 with various shell thicknesses. The morphology of the synthesized structures was investigated using scanning electron microscopy (SEM). Their sizes and shell thicknesses were determined using tunable resistive pulse sensing (TRPS) technique. The optical properties of the synthesized structures were characterized using UV-vis spectroscopy. Ag@TiO2 and Au@TiO2 structures with shell thickness in the range of ≈40-70 nm and 90 nm, for the Ag and Au nanostructures respectively, were prepared using a method we developed and adapted, consisting of a change in the titania precursor concentration. The synthesized nanostructures exhibited significant absorption in the UV-vis range. The TRPS technique was shown to be a very useful tool for the characterization of metal-metal oxide core-shell nanostructures.- Published
- 2017
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19. Changes of c-Myc and DNMT1 mRNA and protein levels in the rat livers induced by dibutyl phthalate treatment.
- Author
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Urbanek-Olejnik K, Liszewska M, Winczura A, and Kostka G
- Subjects
- Animals, DNA (Cytosine-5-)-Methyltransferase 1, DNA (Cytosine-5-)-Methyltransferases genetics, DNA Methylation drug effects, DNA Replication drug effects, Liver metabolism, Male, Promoter Regions, Genetic, Proto-Oncogene Proteins c-myc genetics, RNA, Messenger genetics, RNA, Messenger metabolism, Rats, Rats, Wistar, Reactive Oxygen Species metabolism, DNA (Cytosine-5-)-Methyltransferases metabolism, Dibutyl Phthalate toxicity, Liver drug effects, Proto-Oncogene Proteins c-myc metabolism
- Abstract
We investigated the relationship between dibutyl phthalate (DBP)-induced hypomethylation of the c-Myc promoter region (as evident in our early study) and the expression of c-Myc and DNMT1 genes (at messenger RNA (mRNA) and protein level) in the rat liver. Male Wistar rats received DBP in 1, 3, or 14 daily doses of 1800 mg kg(-1) body weight. Levels of DNMT1, c-Myc mRNA, and proteins were detected using real-time polymerase chain reaction and Western blot analysis, respectively. Our findings indicate that DBP caused an increase in mRNA levels of c-Myc at all time points. The results showed that protein levels of c-Myc in rat liver also increased significantly by DBP treatment, which were more pronounced at last time point (after 14 doses). Furthermore, overexpression of DNMT1gene have been found after one dose of DBP, which was confirmed at the protein level by Western blot analysis. Reduced levels of DNMT1mRNA and proteins (3 and 14 doses) were coordinated with depletion DNA synthesis (reported previously). Based on our previous results and those presented here, the following conclusion could be drawn: (1) DBP exerted biological activity through epigenetic modulation of c-Myc gene expression; (2) it seems possible that DBP-induced active demethylation of c-Myc gene through mechanism(s) linked to generation of reactive oxygen species by activated c-Myc; and (3) control of DNA replication was not directly dependent on c-Myc transcriptional activity and we attribute this finding to DNMT1gene expression which was tightly coordinated with DNA synthesis., (© The Author(s) 2013.)
- Published
- 2016
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20. The effect of acute dichlorodiphenyltrichloroethane exposure on hypermethylation status and down-regulation of p53 and p16INK4a genes in rat liver.
- Author
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Kostka G, Urbanek-Olejnik K, Liszewska M, and Winczura A
- Subjects
- Animals, CpG Islands, Cyclin-Dependent Kinase Inhibitor p16 metabolism, DNA metabolism, DNA (Cytosine-5-)-Methyltransferase 1, DNA (Cytosine-5-)-Methyltransferases genetics, DNA (Cytosine-5-)-Methyltransferases metabolism, Liver metabolism, Male, Promoter Regions, Genetic, RNA, Messenger metabolism, Rats, Rats, Wistar, Real-Time Polymerase Chain Reaction, Tumor Suppressor Protein p53 metabolism, Cyclin-Dependent Kinase Inhibitor p16 genetics, DDT toxicity, DNA Methylation drug effects, Down-Regulation drug effects, Insecticides toxicity, Liver drug effects, Tumor Suppressor Protein p53 genetics
- Abstract
The aim of the study was to investigate the early effect of acute dichlorodiphenyltrichloroethane (DDT) exposure on the methylation status of the promoter region of two tumor suppressor genes: p53 and p16(INK4a) (p16) in rat liver. We analyzed their transcript and protein expression profiles concurrently with the examination of transcriptional and protein expression levels of DNA (cytosine-5)-methyltransferase 1 (Dnmt1). Male Wistar rats were treated with a single dose of DDT (57 mg kg(-1) of body weight) and the methylation status of p53 and p16 genes was examined after 24 h using methylation-sensitive restriction analysis-MSRA. The obtained results indicate that DDT induced alternations in methylation of the promoter region in both p53 and p16 genes. In all the tested samples, the promoter CpG islands of p53 (-261, -179, and -450) were methylated within 100% as compared to control samples (0%). The methylation status of the p16 promoter (-11 and +77) was also altered due to exposure to DDT. Methylated cytosines were detectable in 75% of the tested DNA samples. The Real-time PCR and western blot analyses showed a decrease in mRNA and protein levels of p53, respectively, which was related to the increase in DNA synthesis. These relationships were also observed for mRNA and protein expressions of p16, although to a slighter extent. We also showed that hypermethylation in the promoter region of both tumor suppressor genes was consistent with an increased Dnmt1 mRNA level, and this relationship was further confirmed at the protein level of DNMT1. Concluding, our data suggests that epigenetically mediated changes in gene expression may play an important role in the mechanism of DDT toxicity, including carcinogenic action., (© 2014 Wiley Periodicals, Inc.)
- Published
- 2016
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21. Validation of the analytical method for the simultaneous determination of selected polybrominated diphenyl ethers, polychlorinated biphenyls and organochlorine pesticides in human blood serum by gas chromatography with microelectron capture detector.
- Author
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Matuszak M, Minorczyk M, Góralczyk K, Hernik A, Struciński P, Liszewska M, Czaja K, Korcz W, Łyczewska M, and Ludwicki JK
- Subjects
- Gas Chromatography-Mass Spectrometry, Humans, Endocrine Disruptors blood, Environmental Pollutants blood, Halogenated Diphenyl Ethers blood, Pesticides blood, Polybrominated Biphenyls blood
- Abstract
Background: Polybrominated diphenyl ethers (PBDEs) as other persistent organic pollutants like polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) pose a significant hazard to human health, mainly due to interference with the endocrine system and carcinogenetic effects. Humans are exposed to these substances mainly through a food of animal origin. These pollutants are globally detected in human matrices which requires to dispose reliable and simple analytical method that would enable further studies to assess the exposure of specific human populations to these compounds., Objective: The purpose of this study was to modify and validate of the analytical procedure for the simultaneous determination of selected PBDEs, PCBs and OCPs in human blood serum samples., Material and Methods: The analytical measurement was performed by GC-µECD following preparation of serum samples (denaturation, multiple extraction, lipid removal). Identity of the compounds was confirmed by GC-MS., Results: The method was characterised by the appropriate linearity, good repeatability (CV below 20%). The recoveries ranged from 52.9 to 125.0% depending on compound and level of fortification. The limit of quantification was set at 0.03 ng mL(-1) of serum., Conclusions: The modified analytical method proved to be suitable for the simultaneous determination of selected PBDEs, PCBs and OCPs in human blood serum by GC-µECD with good precision.
- Published
- 2016
22. Risk assessment for pesticides' MRL non-compliances in Poland in the years 2011-2015.
- Author
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Struciński P, Ludwicki JK, Góralczyk K, Czaja K, Hernik A, and Liszewska M
- Subjects
- Consumer Product Safety legislation & jurisprudence, Environmental Monitoring legislation & jurisprudence, European Union, Food Contamination legislation & jurisprudence, Humans, Plants, Edible chemistry, Poland, Retrospective Studies, Risk Assessment methods, Risk Factors, Consumer Product Safety standards, Environmental Monitoring methods, Food standards, Food Contamination analysis, Pesticide Residues analysis
- Abstract
Background: Human exposure to trace levels of pesticide residues present in food of plant origin is inevitable as long as pesticides continue to be applied in agriculture. Since Maximum Residue Levels (MRL) are not toxicological endpoint values, their violation is not by default equivalent to health risk for consumers. However, its essential to provide a health- based risk assessment for each case of MRL non-compliance reported during monitoring and official control of foodstuffs., Objective: To assess the potential short-term risk associated with consumption of food products of plant origin containing pesticide residues above MRL values based on notifications forwarded by the National Contact Point for RASFF in Poland during 2011-2015., Material and Methods: 115 notifications including 127 analytical results non-compliant with respective MRL values were forwarded to provide risk assessment. An internationally accepted deterministic approach based on conservative model assumptions for short-term exposure assessment was applied. The risk was characterized by comparing an estimated dietary intake with respective acute reference dose (ARfD)., Results: Black currant, tea, lettuce, Chinese cabbage and carrot were among the most frequently notified products in years 2011-2015. Among pesticides exceeding respective MRL values, over 90% belonged to fungicides and insecticides/acaricides such as acetamiprid, chlorpyrifos, dimethoate, imidacloprid, dithiocarbamates and procymidone. For 15 and 6 results noncompliant with respective MRL value, a predicted short-term intake exceeded ARfD for children and adults, respectively., Conclusions: Residue levels that could potentially pose a health threat are found incidentally. The science-based and transparent risk assessment process with regard to the data, methods and assumptions that are applied is essential to risk management authorities., Key Words: risk assessment, pesticide residues, MRL, dietary intake, RASFF, food safety.
- Published
- 2015
23. The effect of phenobarbital on gene expression levels of p53 and Dnmt1 in the liver of Wistar rats.
- Author
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Urbanek-Olejnik K, Liszewska M, and Kostka G
- Subjects
- Administration, Oral, Animals, DNA Methylation, DNA Replication drug effects, Liver drug effects, Organ Size drug effects, Rats, Rats, Wistar, Anticonvulsants toxicity, Genes, p53 drug effects, Phenobarbital toxicity, Promoter Regions, Genetic drug effects
- Abstract
Background: Our previous studies have shown that short-term treatment with phenobarbital (PB) resulted in cytosine methylation of CpG sites on the p53 gene promoter in male Wistar rats' liver. Furthermore, PB induced DNA-methyltransferases (DNMTs) activity was also demonstrated; being the enzymes that catalyze methyl group transfer to cytosine in CpG dinucleotides., Objective: Since DNA methylation is involved in regulating gene transcription and that DNMT1 is implicated in regulating DNA methylation, this study assessed whether PB-induced hypermethylation of the p53 promoter region was associated with an altered expression of p53 and Dnmt1 genes., Material and Methods: Male Wistar rats received PB in three daily oral doses (at 24-h intervals) of 92,8 mg/kg b.w. x day-1. Levels of mRNA for p53 and Dnmt1 and levels of relevant proteins were respectively examined by Real-Time PCR and Western blot analysis., Results: Gene expression analysis revealed that exposure of Wistar rats to PB caused statistically significant alternations in the expression of tested genes. We found that both mRNA and protein expression of p53 was down-regulated, whereas expression of Dnmt1 (both mRNA and protein) was up-regulated after PB treatment., Conclusions: Suppression of p53 mRNA and protein expression, which is probably a result of epigenetic changes, (in particular aberrant p53 promoter hypermethylation), can be associated with tumour promoting activity of phenobarbital.
- Published
- 2014
24. [The effect of dibutyl phthalate (DBP) on the methylation and expression level of p53 gene in the liver of Wistar rats].
- Author
-
Urbanek-Olejnik K, Liszewska M, and Kostka G
- Subjects
- Administration, Oral, Animals, Carcinogens toxicity, Gene Expression drug effects, Male, Methylation, RNA, Messenger drug effects, RNA, Messenger metabolism, Rats, Rats, Wistar, Toxicity Tests, Chronic, Dibutyl Phthalate toxicity, Genes, p53 drug effects, Genes, p53 genetics, Liver drug effects, Liver metabolism
- Abstract
Background: Currently, nongenotoxic carcinogens-induced changes in DNA methylation profile are considered as mechanism of their toxicity, including carcinogenic action., Objective: The aim of the study was to determine the effect of dibutyl phthalate (DBP) on the methylation levels of the p53 promoter region, as well as mRNA and protein level of this gene., Material and Method: Male Wistar rats received DBP in one, three or fourteen daily oral doses (at 24-h intervals) of 1800 mg/kg b.w. x day(-1). The methylation level of c-myc gene was determined by PCR-based methylation sensitive restriction enzyme analysis (MSRA). The expression of gene was assessed by Real-Time PCR (at mRNA level) and Western blot (at protein level) analysis., Results: There was observed the hypermethylation of p53 promoter region after short (1 day) exposure of the animals to DBP. No correlation was found between mRNA expression and methylation level of p53 gene. The present study showed decreased level of p53 protein, during the whole period of study., Conclusions: No direct correlation was observed between the methylation and expression level of p53. The decreased protein level might be a consequence of the repressive effect of c-myc, which was involved in signal transduction pathways, the same as p53 protein.
- Published
- 2012
25. [Cumulative exposure to pesticide residues in food].
- Author
-
Kostka G, Urbanek-Olejnik K, and Liszewska M
- Subjects
- Consumer Product Safety standards, European Union, Government Regulation, Humans, Maximum Allowable Concentration, Pesticides analysis, Poland, Environmental Exposure analysis, Environmental Monitoring methods, Food Analysis methods, Food Contamination statistics & numerical data, Pesticide Residues analysis, Risk Assessment standards
- Abstract
The results of food monitoring studies indicate that humans are constantly exposed to residues ofplant protection products (pesticides) in marketed food products. Hence, assessment of the risk to consumers associated with the consumption of products containing residues of the active substances of pesticides is a key stage in both the registration of pesticides and official control of foodstuffs. However there are frequent cases of exposure not only to individual active substances but also to mixtures of pesticide residues. These levels are usually low, below of effective action, and interaction such as synergism orpotentiation is not expected to occur At the same time, literature data indicate that for mixtures sharing a common MOA (Mode of Action/Mechanism of Action), the probability of additive effects is high, even after adjusting for the low levels of the mixed pesticide residues present. Accordingly, health risk assessment for consumers exposed to such mixtures (cumulative/aggregate risk) has become an issue of topical importance. EU-level initiatives regarding the development of appropriate methodology for the estimation of cumulative/aggregate risk have brought about considerable progress in this area. The article discusses various aspects of estimation of cumulative risk for consumers associated with exposure to mixtures of pesticide residues in food.
- Published
- 2011
26. [Toxicogenomics in hazard assessment of chemicals].
- Author
-
Kostka G, Liszewska M, and Urbanek-Olejnik K
- Subjects
- Ecotoxicology organization & administration, Europe, Genomics legislation & jurisprudence, Humans, Organic Chemicals toxicity, Pesticides toxicity, Risk Assessment legislation & jurisprudence, Toxicogenetics organization & administration, Ecotoxicology legislation & jurisprudence, Hazardous Substances toxicity, Toxicity Tests methods, Toxicogenetics legislation & jurisprudence
- Abstract
Recent changes in the European legislation of chemicals suggest an urgent need for introduction of novel, alternative methods for testing chemical substances. Such possibility is offered by toxicogenomics--a scientific discipline combining knowledge from the field of toxicology, i.e., a science investigating the properties of toxic agents and the negative effects these agents exert on health and environment, with genomics, i.e., a science investigating the structure and function of genomes. New research strategies within the field of toxicology (transcriptomics, proteomics, metabolomics) offer conditions to assess the hazards associated with the effects of chemicals with both established and suspected toxic potentials.
- Published
- 2010
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