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Determination of organic tin compounds in the environment
Fojt, Jakub ; Mravcová, Ludmila (referee) ; Řezáčová, Veronika (advisor)
Organotin compounds are one of the most produced and most used organometallic compounds. Some of these substances are endocrine disruptors, persistent organic polutants and their high toxic effects are observed. That’s why their presence in the environment caused by human activity could endanger many organisms. The aim of this thesis is summarize their properties and their occurrence in the environment. Then the quick, easy and relatively cheap method for determination of trialkyltin compounds in heavily poluted aquatic sediments using capillary zone electrophoresis is developed.
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Hormonally active substances in the aquatic environment and risk to aquatic organisms and human.
Duisembay, Zhuldyz ; Bušová, Milena (advisor) ; Ezechiáš, Martin (referee)
This bachelor thesis aims to investigate the presence, sources and impacts of hormonally active substances, or endocrine disruptors (EDs), in the aquatic environment. These substances, including long-lived persistent organic pollutants (POPs), e. g. pesticides and polycyclic aromatic hydrocarbons (PAHs), and non-persistent pollutants such as bisphenol A and alkyphenols, directly or indirectly affect the hormonal systems of aquatic organisms and humans. For instance, it was observed, that elevated concentrations of certain progestogens impact fertility, reproductive processes, induce transcriptional changes, and alter sex ratios within fish populations. Numerous studies in the field focus on evaluating the manifestation of EDs in water, their effects on behavior and vital functions of aquatic organisms and humans, and the challenges associated with their detection and removal from the wastewater discharged into the environment. Recent researches have revealed elevated concentrations of specific EDs in various regions, including Czech Republic (significant concentrations of levonorgestrel, megestrol acetate (MGA), drospirenone and dienogest were detected in Blanice river). This indicates a lack of regulations and potential difficulties in effectively removing these substances from water with...
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Effect of selected perfumes on aromatase activity
Drejslarová, Iva ; Hodek, Petr (advisor) ; Smrček, Stanislav (referee)
Cytochromes P450 are enzymes involved in many physiological processes in the body, besides the metabolism of xenobiotics also in the biosynthesis and catabolism of endogenous substances such as hormones and steroids. Cytochromes P450 that are responsible for the transformation of endogenous compounds can be affected by xenobiotics, which interfere with the secretion, metabolism, transport or elimination of endogenous hormones by various mechanisms. These substances are also referred to as endocrine disruptors and include, for example, pesticides, insecticides, certain pharmaceuticals, or compounds contained in cosmetic products. One of their mechanisms of action is to interfere with steroid hormone biosynthesis through interactions with steroidogenic enzymes. One such enzyme is cytochrome P450 19, aromatase, which catalyses the conversion of testosterone to ß-estradiol in the final step of steroid hormone biosynthesis. Modulation of the activity of this enzyme by endocrine disruptors results in an imbalance of estrogen levels in the body, which can lead to impaired reproduction, osteoporosis, atherosclerosis, dementia, and the development of certain types of cancer. In this context, the effect of commercially available perfumes on the conversion of testosterone to ß-estradiol, which is catalyzed by...
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Vplyv vybraných endokrinných disruptorov na metabolismus lipidov v pečeňových bunkových modeloch
Konopová, Veronika
Endocrine Disrupting Compounds (EDCs) are exogenous compounds that interfere with the endocrine system and consequently elicit toxic outcomes. One of their possible consequences in the organism is their negative impact on metabolic processes linked with development of metabolic diseases, including liver steatosis. In this research area, it is important to develop suitable in vitro cellular models. In this thesis, we evaluated the possibility of using of cell model of immortalized human hepatocytes, MIHA cell line, for detection of activation of nuclear receptors, PXR, LXRa a PPARa, which might be targeted by some EDC. We studied in particular the induction of expression of target genes of these receptors, CYP3A4, SCD, PDK4, CPTT1A, with the aim to compare the sensitivity of MIHA cells with a commonly used of liver cells, HepaRG cell line. The results showed that although some EDC (or model ligands of nuclear receptors) may induce the expression of target genes of nuclear receptors in MIHA cells, in general, this cell model appears to be less suitable for studying the impact of EDC than HepaRG cell line. The MIHA cell line, though, allows to study the compounds activating PPARa, which is an important regulator of metabolism of fatty acids in the liver tissue.
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Effect of on in vitro maturation of porcine oocytes
Laštůvková, Viktorie ; Petr, Jaroslav (advisor) ; Benc, Michal (referee)
Lysmeral (Lilial, Butylphenyl Methylpropional) is a synthetically produced aldehyde. It is used for its typical lily of the valley-like scent as a perfume ingredient in cosmetic products. It is typically found, for example, in cleaning products. It is on the list of the 26 most well-known synthetic allergens and has been shown to be present in human urine and subsequently in wastewater. According to some opinions, lysmeral should be classified as an endocrine disruptor, which are substances that can interfere with the body's endocrine system. As these substances often affect mammalian reproduction, it is in society's interest to address them, given that they are commonly found in the environment. Lysmeral was not properly tested before being placed on the market and all its effects on organisms are still unknown. The hypothesis of this thesis is that exposure to lysmeral causes undesirable changes in the meiotic maturation of porcine oocytes in vitro and the aim is to investigate the effect of lysmeral, at concentrations corresponding to normal human exposures, on specific markers of meiotic maturation of porcine oocytes. The results confirm the negative effect of lysmeral on the smooth progression of meiotic maturation and the achievement of the final stage of porcine oocyte maturation in vitro....
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The Impact of Selected Endocrine Disruptors on Human Spermatogenesis
Vítků, Jana ; Hill, Martin (advisor) ; Pohanka, Michal (referee) ; Lapčík, Oldřich (referee)
Steroid hormones in testis play an important role in spermatogenesis, maintenance of the male reproductive tract, production of semen and the maintenance of secondary sex characteristics and libido. They are also discussed as a target for substances called endocrine disruptors (EDs). No complex study was conducted on evaluation of relationships between EDs and steroid spectrum in 2 biological fluids; seminal plasma and plasma. The aim of the PhD. thesis was to develop and validate a method for determination of bisphenol A (BPA) and steroid spectrum in plasma and seminal plasma and to shed more light into mechanisms of ED action and effects of BPA and polychlorinated biphenyls (PCBs) on human spermatogenesis and steroidogenesis. Two new liquid-chromatography mass spectrometry methods for determination of BPA and 11 steroids in plasma and seminal plasma were developed and validated. The methods were used for estimation of analyte concentrations in 191 men with a different degree of fertility. Concurrently, the levels of six congeners of PCBs, gonadotropins, selenium and zinc in plasma were estimated. Partial correlations adjusted for age and BMI were calculated to evaluate relationships between these analytes. Seminal BPA, but not plasma BPA, was negatively associated with sperm concentration...
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The Impact of Selected Endocrine Disruptors on Human Spermatogenesis
Vítků, Jana
Steroid hormones in testis play an important role in spermatogenesis, maintenance of the male reproductive tract, production of semen and the maintenance of secondary sex characteristics and libido. They are also discussed as a target for substances called endocrine disruptors (EDs). No complex study was conducted on evaluation of relationships between EDs and steroid spectrum in 2 biological fluids; seminal plasma and plasma. The aim of the PhD. thesis was to develop and validate a method for determination of bisphenol A (BPA) and steroid spectrum in plasma and seminal plasma and to shed more light into mechanisms of ED action and effects of BPA and polychlorinated biphenyls (PCBs) on human spermatogenesis and steroidogenesis. Two new liquid-chromatography mass spectrometry methods for determination of BPA and 11 steroids in plasma and seminal plasma were developed and validated. The methods were used for estimation of analyte concentrations in 191 men with a different degree of fertility. Concurrently, the levels of six congeners of PCBs, gonadotropins, selenium and zinc in plasma were estimated. Partial correlations adjusted for age and BMI were calculated to evaluate relationships between these analytes. Seminal BPA, but not plasma BPA, was negatively associated with sperm concentration...
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Effect of endocrine disruptor bisphenol S on human health and reproduction
Procházková, Bára ; Petr, Jaroslav (advisor) ; Děd, Lukáš (referee)
Bisphenol S (BPS) is an environmental pollutant that has replaced bisphenol A (BPA) in plastic and paper products since 2011 as a safer "BPA-free" alternative. However, due to its rapid replacement, its potential adverse effects have not been investigated in detail, and due to its structural similarity to BPA, many studies suggest that it acts, like BPA, as an endocrine disruptor. Its use is wide and BPS is globally widespread, found in the environment and has been detected in both animal and human tissues. Nevertheless, an overall effect of BPS on an organism remains unclear. This work is focusing on gathering sources for its effect on reproductive ability and its association with metabolic disorders.
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Epignetic Modifications of the Sperm and the Application in Clinical Practice of Human Assisted Reproduction Therapy
Štiavnická, Miriama ; Nevoral, Jan (advisor) ; Kloudová, Soňa (referee) ; Vašíček, Jaromír (referee)
Basement of healthy embryo development comes from quality of oocytes and spermatozoa. Today, when percentage of couples suffering infertility together with assisted reproductive therapy (ART) is increasing, understanding to gamete biology and heritable epigenetic code is crucial. The study is focused on promising epigenome based markers that could serve as indicators of gamete quality for either their screening or selection for ART. Accordingly selected markers were used for the investigation of environmental pollutant bisphenol S (BPS) effect on gametes quality. To obtain these aims, we have used human semen samples, boar semen samples and ICR mice gametes. Samples were analyzed by flow cytometry, immunocytochemistry and western blot analysis. All experimental work was in accordance with Ethics committee University Hospital in Pilsen and approved experimental designs for appropriate experimental animal project. In the study, we detected the dimethylation of histone H3 on lysine K4 (H3K4me2) as potential epigenetic marker of sperm quality and chromatin immaturity. Secondly, we observed the role of the gasotransmitter hydrogen sulphide (H2S) as anti-capacitating agents, slowing down capacitation possibly through post-translational modification of proteins. Thirdly, SIRT1 histone deacetylase was...
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