Wyniki wyszukiwania - Biblioteka Nauki

1

Monocykliczne poliprenylowane acylofloroglucynole z szyszek chmielu (Humulus Lupulus) - perspektywa stosowania w żywieniu zwierząt

100%

Stypula-Trebas S.

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2018

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tom 27

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nr 4

2

Comparison of extraction and cleanup procedures for the determination of PCDD/Fs in feed samples with the calux bioassay

63%

Stypula-Trebas S. , Piskorska-Pliszczynska J.

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nr 4

EN

The efficiency of four extraction techniques (shaking extraction, column extraction, accelerated solvent extraction (ASE), and ultrasonic assisted extraction) and two clean-up procedures was evaluated in order to find the best procedure. The ASE proved to be the best extraction method with the highest recovery rales (84%-91%) and imprecision less than 15%. Application of the three- column cleanup procedure delivered slightly better cleanup efficiency in comparison with two-step cleanup but the use of two columns is less time consuming, cost-effective, and enabled to process more samples with the bioassay.

3

Wykrywanie i ocena aktywności związków hormonalnie aktywnych

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Minta M. , Stypula-Trebas S.

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nr 01

EN

During the last two decades concerns have been raised regarding the possible harmful effects of exposure to certain chemicals (natural and synthetic) that can modulate or disrupt the endocrine system (endocrine disrupters, EDs). Their identification and assessment is complicated by a number of mechanisms on which they act. As a result a variety of in silico/in vitro/in vivo methods are used. In this paper the most valuable methods for initial assessment, screening and testing are reviewed. To protect public health, future risk assessment of endocrine disrupters must take into account exposure to the mixtures in which different compounds can interact. The development of fast and sensitive bioassays is crucial to the achievement of this goal.

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Związki hormonalne aktywne w środowisku a zagrożenia zdrowia publicznego

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Minta M. , Stypula-Trebas S.

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nr 08

s.525-529,tab.,bibliogr.

EN

This article is a review of recently published papers dealing with the possible participation of environmental hormonally active compounds (natural and synthetic) in the ethiology of reproductive and other health disorders in animals and man. For some "old" synthetic chemicals (DDT, PCBs, dioxins, diethylstilbestrol, bisphenol A, atrazine and tributyltin) there is a link to the impact on wild animals. It has been hypothesized that in humans these compounds may be responsible for the increased incidence of breast and testicular cancer as well as for reproductive disorders. They generally occur at nontoxic concentrations, but exposure to their mixtures seems to be a major medical challenge. The food and drinking water are the main routes of exposure. During last decades much concern is focused on new groups of chemicals such as brominated flame retardants, phthalates, perfluorinated chemicals, parabens and veterinary drugs (anabolics).

5

Optymalizacja testu wzrostu masy macicy i testu Hershbergera na chomikach z użyciem związków modelowych

51%

Radko L. , Minta M. , Stypula-Trebas S. , Zmudzki J.

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2011

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tom 48

6

Determination of melamine cytotoxicity

51%

Radko L. , Minta M. , Stypula-Trebas S. , Zmudzki J.

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nr 2

223-228

EN

Cytotoxic potential of melamine was evaluated with the use of two in vitro models i.e. cell cultures of rat hepatoma (line FaO) and rat skeletal muscle (line L6). The cultures were exposed for 24, 48, and 72 h to melamine at eight concentrations, ranged from 0.01 to 10 mM. Four different assays were applied in which various biochemical endpoints were assessed: mitochondrial activity - MTT reduction assay, proliferation - Commassie Brilliant Blue (CBB) dye binding assay, lysosomal activity - neutral red uptake (NRU) assay, and membrane integrity - LDH release assay. Effective concentrations (EC₂₀, EC₅₀, EC₈₀) were calculated from concentration-response curves, and then they were averaged over three independently conducted experiments. It was found that MTT assay was the most sensitive to this compound. After 48 h exposure EC₅₀ values (mM, mean ± SD) for FaO and L6 cells were 6.4 ± 0.62, and 8.2 ± 1.51, respectively. The inhibition of lysosomal activity measured by NRU assay, and damage of plasma membrane measured by LDH assay were detected in L6 (but not in FaO) cells; however, the effects took place after longer (72 h) exposure. At that time EC₅₀ values were 5.2 mM and 9.2 mM for NRU and LDH, respectively. In spite of the low cytotoxicity of melamine, more studies are needed for hazard identification and characterization of the compound.

7

Ocena aktywności hormonalnej prenyloflawonoidu chmielowego w kontekście stosowania odpadów browarnianych w żywieniu zwierząt

51%

Stypula-Trebas S. , Radko L. , Posyniak A.

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nr 2

8

Cytotoxic effects of the synthetic oestrogens and androgens on Balb/c 3T3 and HepG2 cells

51%

Minta M. , Radko L. , Stypula-Trebas S. , Zmudzki J.

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nr 4

EN

The aim of the study was to test and compare the cytotoxic potential of two synthetic oestrogens: diethylstilboestrol (DES) and ethinyloestradiol (EE₂) and two androgens: testosterone propionate (TP) and trenbolone (TREN) on two cell lines. The fibroblast cell line Balb/c 3T3 and the hepatoma cell line HepG2 were selected. To get more insight into the mode of toxic action, four methods were used, which evaluated different biochemical endpoints: mitochondrial activity (3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide reduction assay), lysosomal activity (neutral red uptake assay), total protein content, and lactate dehydrogenase release. Cytotoxicity was assessed after 24, 48, and 72 h exposure to eight concentrations ranging from 0.78 to 100 µg/mL. Concentration- and time- dependent effects were observed. Depending on the line and assay used, half maximal effective concentration after 72 h (EC₅₀₋₇₂ₕ) values ranged as follows: DES 1-13.7 µg/mL (Balb/c 3T3) and 3.7-5.2 µg/mL (HepG2); EE₂ 2.1-14.3 µg/mL (Balb/c 3T3) and 1.8-7.8 µg/mL (HepG2); TP-14.9-17.5 µg/mL (Balb/c 3T3), and 63.9- 100 µg/mL (HepG2); and TREN 11.3-31.4 µg/mL (Balb/c 3T3) and 12.5-59.4 µg/mL (HepG2). The results revealed that oestrogens were more toxic than androgens and the most affected endpoint was mitochondrial activity. In contrast to oestrogens, for which EC₅₀₋₇₂ₕ values were similar in both lines and by all assays used, Balb/c 3T3 cells were more sensitive than HepG2 cells to TP.

9

Differential toxicities of albendazole and its two main metabolites to Balb/c 3T3, HepG2, and FaO lines and rat hepatocytes

51%

Radko L. , Minta M. , Stypula-Trebas S.

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nr 4

10

Evaluation of the recombinant cell-based bioassay as a screening method for PCDD/Fs monitoring in fish tissue

45%

Stypula-Trebas S. , Warenik M. , Gembal M. , Malagocki P. , Piskorska-Pliszczynska J.

Environmental Biotechnology

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2009

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tom Vol. 5, No. 1

32-41

EN

Among 210 congeners only 17 highly toxic, 2,3,7,8-chlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) are of toxicological concern. They exhibit high binding affinity to an intracellular aryl hydrocarbon receptor (AhR), causing harmful effects at exposure levels of thousands of times lower than most environmental toxicants. The Chemically Activated LUciferase gene expression bioassay (CALUX) utilizes recombinant cells that were transfected with a luciferase reporter gene, which responds to dioxin-like compounds with the induction of luciferase in a time-, dose-, AhR-dependent and chemical-specific manner. The bioassay evaluation concerning the European Community (EC) requirements for the PCDD/Fs determination for the official control of foodstuffs was performed on salmon tissue. In order to evaluate the bioassay performance characteristics, recovery range, limit of detection (LOD), limit of quantification (LOQ) and precision were determined. The results revealed that combining a dichloromethane: hexane extraction, an acid silica plus activated carbon clean-up provides reliable, reproducible (CV = 9-20%) measurements with acceptable recovery (78%) and sensitivity at the required ppt range. Due to the low cost and high throughput characteristics of the CALUX assay, food monitoring for PCDD/Fs may benefit from use of this bioassay as a prescreening tool to select and prioritize samples for subsequent analysis by high resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). Although the bioassay may not be able to specify identity of the reactive substances, it may serve as a very useful tool for the evaluation of contamination sources.

11

Usefulness of immature golden hamster (Mesocricetus auratus) as a model for uterotrophic assay

45%

Radko L. , Minta M. , Jasik A. , Stypula-Trebas S. , Zmudzki J.

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tom 59

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nr 4

EN

The present study assessed the sensitivity of immature hamster uterotrophic assay to reference oestrogen agonists/antagonists in order to develop a sensitive model for evaluation of endocrine-active compounds in diets. After performing a baseline for control animals, the sensitivity of immature females (postnatal day 18) to reference compounds was evaluated in a three-day uterotrophic assay. The absolute and adjusted dry uterine weights, fold induction over control for absolute wet uterine weight, and wet uterine weight/body weight ratio (%) were used as endpoints. The significantly active doses for reference oestrogens were as follows: 0.6 µg/kg for 17α-ethinyloestradiol (s.c.): 1 µg/kg/day (s.c.) and 40 µg/kg (p.o.) for diethylstilboestrol; 40 mg/kg (s.c.) and 160 mg/kg (p.o.) for bisphenol A. Co-treatment with tamoxifen at a dose of 1 mg/kg significantly antagonised the uterotrophic effect induced by 1 µg/kg 17α-ethinyloestradiol, and showed the attenuated proliferative effect in histopathological examination. We found immature hamster uterotrophic assay as a sensitive model that could be a good alternative to the rat assay.

12

Wpływ mykotoksyn wykrywanych w paszach na rozwój ryb Danio rerio

45%

Radko L. , Jedziniak P. , Jakubaszek A. , Stypula-Trebas S. , Posyniak A.

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nr 2