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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Vliv vybraných potravních doplňků na metabolismus karcinogenů přítomných v potravě / Vliv vybraných potravních doplňků na metabolismus karcinogenů přítomných v potravě

Fousová, Petra January 2014 (has links)
The consumption of dietary supplements such as flavonoids may reduce risk of many civilization diseases. Flavonoids are able to modulate the activity of cytochromes P450 (CYPs), xenobiotic-metabolising phase I enzymes of biotransformation that are involved in the activation and detoxification of food-derived carcinogens. Inhibition of CYP activities by flavonoids has been extensively studied because of their potential use as agents blocking the initiation stage of carcinogenesis. On the other hand, flavonoids have been shown to enhance the activation of carcinogens and/or influence their metabolism via induction of specific CYPs. In the first part of this study, flavonoids dihydromyricetin and α-napthoflavone were explored for their possible effects on CYP1A1 expression and activity when administered in combination with carcinogen benzo[a]pyrene (BaP). For this purpose, liver, small intestine and colon microsomal fractions were isolated from treated rats and induction of CYP1A1 was evaluated by immunodetection and EROD activity measurements. In liver and small intestine, all combinations of BaP and flavonoids led to strong induction of CYP1A1 expression. Moreover, the CYP1A1 protein levels were almost identical to levels observed when the rats were treated with BaP alone. However, in comparison...
22

Vliv inhibice proteazomu na antiproliferační účinek antracyklinových antibiotik. / The effect of the proteasome inhibition of the antiproliferative effect of anthracycline antibiotics.

Kroupová, Jana January 2016 (has links)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biochemical Sciences Candidate: Jana Kroupová Supervisor: PharmDr. Anna Jirkovská, Ph.D. Title of diploma thesis: The effect of the proteasome inhibition of the antiproliferative effect of anthracycline antibiotics Anthracycline antibiotics (daunorubicin, doxorubicin) belong to the most effective antitumor drugs. In current clinical practice they are used mostly in the combinations with either "classical" or new targeted antitumor drugs. The proteasome inhibitors (bortezomib and carfilzomib) are also viewed as a part of new "targeted" antitumor drugs. The proteasome is a multienzyme complex in eukaryotic cells which is responsible for intracellular degradation of proteins. The proteasome inhibitors have been largely used in the therapy of multiple myeloma, but their potential has been also studied in the case of other malignancies. Their use in the combination with anthracyclines could be a possible alternative in the therapy of some tumor illnesses, but the effect of combination of anthracyclines and proteasome inhibitors on tumor cells have not been sufficiently explained. The anthracycline therapy is also accompanied by serious adverse side effect - the cardiotoxicity, which potential could be influenced by the...
23

Modulace aktivity HIV-1 proteasy / Modulation of HIV-1 Protease Activity

Pokorná, Jana January 2013 (has links)
HIV-1 protease plays a crucial role in the late state of the life cycle of HIV virus when it cleaves the viral polyprotein precursors into the structural and functional proteins. If it is effectively inhibited, HIV particles remain immature and noninfectious. The application of highly active antiretroviral therapy (HAART) including protease inhibitors can reduce plasma HIV-1 levels below the detection limit in adherent patients and thus dramatically change their life expectancy. The clinical utility of the first inhibitors was limited by severe side effects, low bioavailability, high pill burdens, and rapid development of viral resistance under the selection pressure of HIV antiretrovirals. To overcome these difficulties, second-generation inhibitors were developed. Despite an indisputable improvement they brought to antiretroviral therapy, the development of new highly active HIV-1 protease inhibitors with optimal pharmacokinetic properties, higher metabolic stability, little off-target activity, and particularly, more favorable resistance profiles is still of high importance. This thesis provides an overview of anti-HIV- drugs including development of substituted metallacarboranes, a new class of potent, unusual, nonpeptidic HIV protease inhibitors with therapeutic potential. Next, the impact of...
24

Hodnocení jaterní toxicity in vitro / Evaluation of liver toxicity in vitro

Kafuňková, Kateřina January 2020 (has links)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology and Toxicology Student: Kateřina Kafuňková Supervisor: RNDr. Jana Maixnerová, Ph.D. Title of diploma thesis: Evaluation of liver toxicity in vitro The subject of the diploma thesis is toxicity evaluation of newly synthesised substances on a cellular model representing a hepatocyte. The tested substances have been provided by the Department of Organic and Bioorganic Chemistry at the Faculty of Pharmacy in Hradec Králové, Charles University, as potential antifungal pharmaceuticals and medicine effective against Methicillin-resistant Staphylococcus aureus (MK-NO2-1, MK-NO2-2, DAB-5-K, PABA-Me-5, PABA-Et-5, MK-F-1, PABAN- 3, PABAN-5, MK-F-2, MK-CF3-1, MK-CF3- 2). In order to determine the toxicity we have implemented two methods. The first method is based upon measuring metabolic activity of cells by means of reducing tetrazolium to a colored product. The second method detects the amount of LDH released as a marker of toxicity. The human hepatoma cell line HepG2was used as a model. . The IC50 and EC50 parameters were used to assess the degree of viability and cytotoxicity. The final values obtained from the first method indicated all tested substances showed a certain level of toxicity to the hepatic tissue. MK-CF3-2 is the most...
25

Fixace olova v alkalicky aktivovaných materiálech na bázi různých typů popílků / Fixation of the lead in alkali activated materials based on different types of ashes

Cába, Vladislav January 2020 (has links)
The aim of this work was to develop an alkali activated matrix based mainly on fly ash, to determine the ability to fix lead in these matrices, the impact of added lead on mechanical properties and to reveal the way of lead fixation in these matrices. The matrices consisted mainly of fly ash (four from fluidized bed combustion, one pulverized coal combustion) with an admixture of blast furnace slag and sodium silicate as an activator. Lechates were prepared on the basis of the ČSN EN - 12457-4 standard, lead concentrations in them were measured using an atomic emission spectrometer with inductively coupled plasma. The strengths of the samples were measured after 28 days. Images, element maps and element spectra were taken to determine the structure using a scanning electron microscope with an electron dispersion spectrometer, the samples were analyzed on an infrared spectrometer with a Furier transform, X-ray diffraction analysis and electron spectroscopy for chemical analysis were also used. The individual measurements showed that lead is accumulated in the form of hydroxide. The impact of lead doping on strength of the matrix was different for individual samples. Matrices from both types of fly ash released minimal amounts of lead into leachates, so it is possible to use them to fixate lead.
26

Inhibice enzymové aktivity cytochromů P450 endokrinním disruptorem 17α-ethinylestradiolem / Inhibition of enzyme activity of cytochromes P450 by endocrine disruptor 17α-ethinylestradiol

Otáhalová, Barbora January 2020 (has links)
17α-ethinylestradiol (EE2) is a synthetic hormone, derivative of the natural hormone estradiol. EE2 is one of the the most prescribed drugs in the world. It belongs to the estrogenic endocrine disrupter chemicals. These compounds are able to alter functions of the endocrine system and cause adverse effects in the organism, offspring and (sub)population. In this thesis, there are observed effects of 17α-ethinylestradiol on enzyme activities of main enzymes involved in phase I of xenobiotic biotransformation, i.e. cytochromes P450 (CYP), in vitro. Isoforms of CYP subfamilies 1A, 2B, 2C, 2E and 3A were studied in rats and humans. Each CYP isoform was incubated with EE2 at two concentrations, 10μM EE2 and the concentration corresponding to the substrate concentration in the specific marker reactions of individual CYP isoforms. The results indicate, that in rat liver microsomes the activity of all studied isoforms except CYP1A2 was decreased in the presence of EE2. When EE2 was added to the incubation mixture at the concentration of the reaction substrate, the greatest decrease in enzyme activity was observed for CYP2C6, with the remaining activity only 36%. In human liver microsomes, the activity of CYP2B6, CYP2C9, CYP2E1 and CYP3A4 was also effected by EE2. As in the case of rat model, CYP2C subfamily...
27

Biologická aktivita sekundárních metabolitů rostlin XXX. Základní screening vybraných taxonů na anticholinesterasovou aktivitu. / Biological activity of plants secondary metabolites XXX. Basic search of selected taxons on anticholinesterase activity.

Karaščáková, Diana January 2020 (has links)
CHARLES UNIVERSITY Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Botany Candidate: Diana Karaščáková Supervisor: prof. RNDr. Lubomír Opletal, CSc. Title of diploma thesis: Biological activity of plants secondary metabolites XXX.; Basic search of selected taxons on anticholinesterase activity As part of the study of the biological activity of secondary metabolites, 7 taxa of higher plants were selected. The study deals with basic research of summary and alkaloid extracts prepared from morphological parts of plants Annona muricata (leaves), Leonotis leonurus (perch), Turnera diffusa (perch), Hamelia patens (perch), Uncaria guianensis (bark), Allamanda cathartica (perch) and Morinda citrifolia (leaves). To elucidate the presence of the major types of secondary metabolites, extracts were prepared and subjected to detection reactions by TLC using ten detection reagents. After detection by Dragendorff's reagent of ethyl acetate extracts, alkaloids were significantly present only in Annona muricata. Alkaloids were not detected in the bark of Uncaria guianensis. Using the Ellman method, the extracts were tested for potential inhibitory activity against human brain cholinesterases, using both recombinant enzymes. No significant active substances were present in any of the measured...
28

Hodnocení fytotoxicity průsakových vod ze skládky tuhých komunálních odpadů Bukov

Šourková, Markéta January 2019 (has links)
Master thesis is focused on the monitoring and evaluation of the phytotoxicity of lea-chate of municipal solid waste landfill from Bukov. Introduction includes statistical data, waste management methods, legislation and terminology of waste management. Further, the thesis contains a description of the landfilling process with a focus on water monitoring, description of phytotoxicity tests and basic information about Bukov municipal solid waste landfill. Experiment is focused on phytotoxicity tests of leachate water from a given landfill. The final part contains the evaluation of the results and their in-terpretation.
29

Vliv neurosteroidů na aktivitu neuronální sítě in vitro. / Neurosteroid effects on neuronal network activity in vitro.

Strnadová, Lenka January 2021 (has links)
GABA receptors type A (GABAAR) are ligand-gated ion channels permeable for chloride anions. In the mammalian brain they mediate most of the inhibitory transmission. Moreover, the dysfunctions of the GABA-mediated system result in many neurological disorders, including epilepsy, anxiety and depression. Neurosteroids are cholesterol metabolites interacting with a variety of membrane receptors and have a direct effect on neuronal excitability. The neurosteroids allo-pregnanolone (allo-PA) and pregnanolone (PA) are potent positive modulators of the GABAAR. The goal of this work is to establish a newly constructed application system and a calcium imaging method using the GCaMP sensor to examine the effects of PA on the activity of primary hippocampal cultures. In this work we validate the application system and test the GCaMP calcium sensor in vitro. Application of PA inhibited the spontaneous calcium peaks, which agrees with its known actions on the GABAAR. We discovered that the neurosteroid inhibitory effect on the neuronal network activity changes after repeated applications. The results suggest that there might be some compensatory actions on the GABAAR level during prolonged or repeated exposition to PA. Key words: GABAAR; neurosteroid; pregnanolone; allopregnanolone; calcium; GCaMP; inhibition
30

Příprava inhibitorů chřipkové neuraminidasy a polymerasy / Preparation of Influenza Neuraminidase and Polymerase Inhibitors

Zima, Václav January 2021 (has links)
Influenza is an infectious disease caused by the influenza virus. This virus causes a severe viral infection that spreads easily from person to person in yearly pandemics. Vaccination is the most effective way to prevent the infection, however, due to the high rate in mutations of the virus, the vaccine needs to be often reformulated. Another option to combat influenza is based on administration of antiviral drugs. Clinical studies of isolated influenza strains ("avian flu" H5N1, 2004; "swine flu" H1N1, 2009) revealed resistance towards known influenza neuraminidase inhibitors (zanamivir, oseltamivir). The resistance is caused by structural changes close to the enzymatic site. This calls for the development of new neuraminidase inhibitors as well for development of inhibitors targeting different influenza enzymes. This Thesis is focused on design and synthesis of new inhibitors of influenza neuraminidase and RNA-dependent RNA polymerase, namely PA subunit and the assembly of PA-PB1 heterodimer enzymes (Scheme 1). Influenza neuraminidase inhibitors were prepared by C-5 derivatization of oseltamivir followed by subsequent extension of its structure with binders of 150-cavity. Binding potencies of new oseltamivir derivatives against two influenza strains were determined. The next part contributed to...

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