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Study of redox and adsorption features of bile acids on hanging mercury drop electrode
Yershova, Polina ; Schwarzová, Karolina (advisor) ; Gajdár, Július (referee)
Bile acids are the end products of cholesterol metabolism and are important biological surfactants. The curved shape of their chains allows the cyclization of molecules, and the formation of a supramolecular structure. The goal of this thesis was to study the electrochemical and adsorption behavior of selected bile acids: lithocholic, deoxycholic and cholic acids. The measurements were carried out in the medium Brittonův-Robinson buffer:methanol in the ratio 9:1 using cyclic voltammetry and AC voltammetry methods and measuring the dependence of the differential capacitance Cd on the applied potential E. A hanging mercury drop electrode was used as a working electrode. The measurements showed that bile acids are adsorbed on the surface of the electrode and organizing themselves in self assembled monolayers (SAM). In our case we have observed formation of 2D condensed layers as specific form of SAM. Transfer techniques were used to demonstrate bile acid adsorption. A study of the behavior of lithocholic acid as a function of different pH values showed that only at pH 10.0 to 12.0 2D 2D condensation occurs, i. e. that at pH values in the range of 2.0 to 9.0 it is another type of adsorption. On AC voltammograms, there are a maximum of two areas in which peaks occur: the first is around -0.2 V and the...
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A new approach to the electroanalysis of primary bile acids and related steroids
Klouda, Jan ; Schwarzová, Karolina (advisor) ; Skopalová, Jana (referee) ; Vyskočil, Vlastimil (referee)
In this doctoral thesis, a novel method for the determination of primary bile acids cholic acid and chenodeoxycholic acid is presented. Bile acids play various vital roles in the mammalian body. Moreover, their determination is extremely helpful in liver and biliary disease diagnosis and management. These saturated organic compounds lack strong chromophores and fluorophores in their structure, and thus are usually hard to detect in spectroscopy. For this reason, either instrumentally advanced but expensive methods, such as mass spectrometry, or less reliable enzymatic methods are commonly employed in bile acids quantitation. Hence, the demand for simple and reliable methods for their determination is strong. Bile acids are also known to be virtually inert for direct electrochemical oxidation. Herein, a simple method for their chemical activation for electrochemical oxidation on bare electrode materials was developed, optimized and applied to cholic acid and chenodeoxycholic acid determination. The activation is based on a dehydration reaction of a primary bile acid with 0.1 mol L-1 HClO4 in acetonitrile (water content 0.55%) that introduces double bond(s) into the originally fully saturated steroid core. This naturally increases the electron density in the structure, and thus allows electrochemical...
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Alternation of bile production due to iron depletion.
Šimková, Marie ; Prašnická, Alena (advisor) ; Hyršová, Lucie (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Biological and Medical Sciences Student: Marie Šimková Supervisor: Mgr. Alena Prašnická Title of diploma thesis: Alternation of bile production due to iron depletion Introduction: Liver has an irreplaceable role in the production and secretion of bile. This body fluid serves as the main excretion way of some endogenous and exogenous substances. Another liver property is the ability to store substances essential for correct functions of the body, e.g. iron. It has been shown that iron could have an impact on the bile production and secretion. Aim: The aim of this diploma thesis was to discover an impact of iron depletion on the bile synthesis and metabolism, especially on bile acids, and the way it affects transporters expression. Methods: Male Wistar rats (n=6 in each group, 250 ± 20 g) were divided into two groups: control group (Chow diet) fed with standard diet and iron depletion group (ID), fed with iron depletion diet for 21 days. To investigate the changes in bile flow, the bile had been collected for 120 min during in vivo clearance study. The analysis of the changes in expression of bile transporters and enzymes responsible for de novo bile acid synthesis was performed at the mRNA (qRT-PCR) and protein (Western blot)...
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Alternation of bile production due to iron depletion.
Šimková, Marie ; Prašnická, Alena (advisor) ; Hyršová, Lucie (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Biological and Medical Sciences Student: Marie Šimková Supervisor: Mgr. Alena Prašnická Title of diploma thesis: Alternation of bile production due to iron depletion Introduction: Liver has an irreplaceable role in the production and secretion of bile. This body fluid serves as the main excretion way of some endogenous and exogenous substances. Another liver property is the ability to store substances essential for correct functions of the body, e.g. iron. It has been shown that iron could have an impact on the bile production and secretion. Aim: The aim of this diploma thesis was to discover an impact of iron depletion on the bile synthesis and metabolism, especially on bile acids, and the way it affects transporters expression. Methods: Male Wistar rats (n=6 in each group, 250 ± 20 g) were divided into two groups: control group (Chow diet) fed with standard diet and iron depletion group (ID), fed with iron depletion diet for 21 days. To investigate the changes in bile flow, the bile had been collected for 120 min during in vivo clearance study. The analysis of the changes in expression of bile transporters and enzymes responsible for de novo bile acid synthesis was performed at the mRNA (qRT-PCR) and protein (Western blot)...
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Genetic diseases of the liver
Šepsová, Marika ; Doleželová, Eva (advisor) ; Tripská, Katarína (referee)
Author: Marika Šepsová Title: Genetic diseases of the liver Form: Bachelor Thesis University: Charles University, Faculty of Pharmacy in Hradec Králové Degree: Medical Laboratory Technician Liver function may be affected by various factors including genetic diseases. The aim of this bachelor thesis is to collect and summarize current information about genetic diseases of the liver. Diseases with the highest incidence in the population are Dubin-Johnson syndrome, Rotor syndrome, Crigler-Najjar syndrome and Gilbert's syndrome. They are known as inherited hyperbilirubinemia characterized by an impairment in bilirubin metabolism. These genetic diseases are very rare with exception of Gilbert's syndrome. However, despite low prevalence and incidence it is necessary not to prolong their diagnosis. Most of them do not have any complications and do not require any treatment. The exception is Crigler-Najjar's syndrome, as untreated can have fatal consequences. Wilson's disease and hereditary hemochromatosis are inherited disorders of metal metabolism. Wilson's disease is a rare disease caused by an impairment in copper metabolism. Inherited hemochromatosis causes excessive iron deposition in the liver and other organs. Alpha-1 antitrypsin deficiency is characterized by impaired alpha-1 antitrypsin protein...
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Endoglin and livers
Jozefčeková, Nikola ; Doleželová, Eva (advisor) ; Prašnická, Alena (referee)
Author: Nikola Jozefčeková Title: Endoglin and liver Form: Diploma Thesis University: Charles University, Faculty of Pharmacy in Hradec Králové Degree: Pharmacy This diploma thesis concludes the available information about endoglin, its isoforms in the liver and its impact on the liver during various pathological conditions. In the first part of the thesis describes morphology and physiology of the liver, its structure, histology and metabolic functions. Second part contains an information about endoglin, its isoforms and role in TGF-β signaling complex, expression of endoglin and regulation of the expression. In the third part are described liver diseases during which is expression of endoglin changed. This part deals with the significance of endoglin as a diagnostic and prognostic marker. Endoglin (CD105, TGF-β receptor III) is a homodimeric transmembrane glycoprotein and a membrane co-receptor TGF-β with high expression in endothelial cells. Endoglin plays an important role in the vascular development. Endoglin is involved in the processes of angiogenesis, vascular homeostasis and TGF-β signalization. It affects activity of TGF-βRII, ALK1 and ALK5 receptors. Due to the interactions with TGF-β complex, modulation of activity of ALK receptors and Smads, endoglin controls fibrotic and anti-...
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Synthesis of ligands for farnesoid X receptor
Kašpar, Miroslav ; Chodounská, Hana (advisor) ; Kasal, Alexander (referee)
Farnesoid X receptor is mostly expressed in liver cells and its activation may be used for the treatment of cirrhosis causing diseases, especially biliary cirrhosis and nonalcoholic steatosis. These two latter diseases are most common in developed countries and, as of date, no effective treatments are available. Therefore, the aim of this project is the design and synthesis of novel bile acid analogues with subsequent biological evaluation towards farnesoid X receptor. Thus, a series of new compounds were designed using computational modeling studies and chemical synthesis was done to develop structure-activity relationships. Chemical structure analysis and purity was confirmed by conventional analytical methods. Finally, synthetic compounds were profiled against farnesoid X receptor in collaboration with the Pharmaceutical faculty of Charles University in Hradec Králové. Keywords: farnesoid X receptor, FXR, bile acids
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The Development of HPLC-FLD Method for the Determination of the Bile Acids in the Bile of Mice
Kacerovská, Veronika ; Nesměrák, Karel (advisor) ; Bosáková, Zuzana (referee)
Aim of the master thesis was the development and the optimization of the HPLC method with fluorescence detection for the determination of the bile acids in the bile of mice. On the basis of literature, the HPLC-FLD method has been proposed and optimized for the quantification of eight bile acids (cholic acid, glycocholic acid, deoxycholic acid, glycodeoxycholic acid, chenodeoxycholic acid, glycochenodeoxycholic acid, α-muricholic acid, and λ-muricholic acid) in the biological material. 1,2-benzo-3,4-dihydrocarbazole-9-ethyl-p-toluenesulfonate is suitable derivatization reagent for labeling of the bile acids. The calibration dependences, limits of detection and quantification (in the range of 0.88-1.78 μmol dm -3 ) for all bile acids are measured. In the biological sample five bile acids have been successfully identified and then determined (cholic acid, glycocholic acid, glycodeoxycholic acid, glycochenodeoxycholic acid, and α-muricholic acid). Key words: bile acids, HPLC, fluorescence detector, derivatization reaction, bile
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The use of mercury-based electrode materials for the study of electrochemical reduction of selected bile acids
Hulová, Dagmar ; Schwarzová, Karolina (advisor) ; Navrátil, Tomáš (referee)
The electrochemic's behaviour of the bile acids (cholic, glycocholic, deoxycholic, ursodeoxycholic and lithocholic acid) was studied on the meniscus-modified silver solid amalgam electrode (m-AgSAE) by differential pulse voltammery. Bile acids provide in the solution of the Britton - Robinson buffer and methanol (9:1) in the pH range 3.0 to 12.0 a cathodal signal in the high negative potentials: cholic acid, deoxycholic acid, ursodeoxycholic acid and lithocholic acid about −1400 mV and glycocholic acid, which alone is the conjugate with glycine, about −1500 mV. Cholic acid, glycocholic acid, deoxycholic acid and ursodeoxycholic acid provide the highest peaks to pH 5.0, approximately in their pKa values. Lithocholic acid provides peaks from pH 7.0. It was demonstrated by the cyclic voltammetry that the electrochemical behavior is influenced by the adsorption of the bile acids to the electrode; presumed reaction at the working electrode - a reduction of a proton of a carboxylic group, is controlled by the diffusion and the process is quasireversible. Utilization of the electrochemical reduction of bile acids for the voltammetric determination does not seem very suitable. It has been proven that the presence of the methanol deteriorates the measuring results for glycocholic acid. In the presence of...
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Electrochemical oxidation of Bile Acids on Carbon Based Electrodes. The Possible Use in Electroanalysis.
Klouda, Jan ; Nesměrák, Karel (advisor) ; Zima, Jiří (referee)
The goal of this master's thesis was to examine the possibility of oxidation of seven selected bile acids and evaluate whether such processes are suitable for analytical purposes. The secondary goal was to describe the oxidation products of bile acid electrolysis. The experiments were carried out in a non-aqueous medium of acetonitrile and in a mixed medium of acetonitrile:water using linear sweep and cyclic voltammetry. The working electrode materials employed for voltammetric experiments were: highly oriented pyrolytic graphite, -cyclodextrin modified glassy carbon and boron doped diamond. Preparative electrolysis was carried out on a platinum electrode in the non-aqueous medium of acetonitrile. Experiments have shown that neither the highly oriented pyrolytic graphite electrode nor the -cyclodextrin modified glassy carbon electrode are suitable for analytical purposes under conditions used. The results achieved on the boron doped diamond electrode, on the other hand, have not yet been described in the literature. Primary bile acids cholic and chenodeoxycholic were oxidized at approximately 0.5 V lower potential in the mixed medium of acetonitrile:water than in the papers using carbon electrodes published until now. Products of oxidation on the platinum electrode were separated by TLC and...
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