National Repository of Grey Literature 103 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Voltammetric behaviour of cholesterol and lanosterol on boron doped diamond electrode
Kubešová, Jana ; Schwarzová, Karolina (advisor) ; Nesměrák, Karel (referee)
The aim of this thesis is to investigate procedures leading to regeneration of boron- doped-diamond's (BDD electrode) surface and study of voltammetric behaviour of cholesterol and lanosterol on BDD electrode. Three options of regeneration of electrode's surface were were studied: the stirring, the mechanical polishing using alumina and the anodic oxidation. The anodic oxidation was studied using electrolytes: 0,1 mol l−1 perchloric acid in acetonitrile, 0,1 mol l−1 sodium perchlorate in acetonitrile and tetrahexylammonium hexafluorofosphate in acetonitrile. Each electrolyte was studied with 0 or 0,43 % and 20 % volume of water. Further, voltammetric behaviour of cholesterol on BDD electrode in the presence of 0,1 mol l−1 perchloric acid in acetonitrile was investigate. The second part of the thesis was the study of voltammetric behaviour of lanosterol on BDD electrode in the presence of 0,1 mol l−1 perchloric acid in acetonitrile and 0,1 mol l−1 sodium perchlorate in acetonitrile. The study was performed using cyclic voltammery. Lanosterol provides two anodic signals in the presence of both electrolytes, the first one at the potential of +1200 mV, the second one at the potential of +1500 mV. The stability of lanosterol in the presence of perchloric acid and sodium perchlorate was studied by...
Chemical experiments for high school - chromatography with natural substances.
Polívková, Michala ; Hybelbauerová, Simona (advisor) ; Klímová, Helena (referee)
This thesis concerns experiments with natural compounds and vitamins. In the first part I described these substances, which I proved by chromatography or I made other experiments with them in the second part. I created four worksheets with instruction for laboratory practise. There are thein solutions in the supplement. I verified these four experiments at Grammar School in Prague 9.
Drop coating deposition Raman spectroscopy of liposomes with different compositions
Antalík, Andrej ; Kočišová, Eva (advisor) ; Holoubek, Aleš (referee)
Method of drop-coating deposition Raman spectroscopy is a special tech- nique that employs deposition of a small droplet of the sample on a hydro- phobic surface with subsequent solvent removal by evaporation. As a result the concentrated material forms a ring at the edge of the droplet. This techni- que has proven to be efficient for liposome studies at low concentrations. We focused on a study of spectral changes and ring formation in phosphatidylcho- line liposomes due to increasing amount of cholesterol. Higher concentration of cholesterol didn't cause significant changes in membrane structure, such as phase transition, however the ring wasn't formed. Second part of this bache- lor thesis concerns with the search for some alternative surface to previously used SpectRIM TM DCDR plates made by Tienta Sciences, Inc. which are no longer available. The polished calcium fluoride glass (CaF2) seems to be the most suitable for the further use from all tested surfaces. Raman signal at the other surfaces was either weak or spectral bands that don't belong to lipid were observed.
Cholesterol and Lipoproteins, Their Metabolism and Effect on Human Health
Záhořová, Karolína ; Pavlasová, Lenka (advisor) ; Ehler, Edvard (referee)
Cholesterol and lipoproteins, their impact (aspect) on human health The thesis is focused on cholesterol, lipoproteins and their metabolism. Detail is devoted to their charakteristics, significance, function in the body and the effects on human health. The first chapter summarizes informations about cholesterol chemical properties and structure, through its processing to the characteristic, importance and function in the human body. There are analyzed opportunities to affect cholesterol levels. The second chapter presents lipoproteins as particles for our body essential. It includes their characteristic, classification, meaning and function in the body. The third chapter provides information about dyslipidemia. It focuses on the classification, significance and treatment. The following chapter deals with atherosclerosis, its causes, consequences and risks. A recent chapter presents a brief overview from part of laboratory analyzes on lipid and lipoproteins. Key words: Cholesterol, lipoprotein, dyslipidemia, hyperlipoproteinemia, atherosclerosis.
Serum markers of cholesterol 7α hydroxylase activity
Bohdanecká, Alena ; Leníček, Martin (advisor) ; Kovář, Jan (referee)
Cholesterol 7-hydroxylase (CYP7A1) is the rate limiting enzyme of the classical pathway of bile acid (BA) synthesis, which catabolizes approximately half of cholesterol in man. Determination of CYP7A enzymatic activity is a key subject of lipid metabolism research. Direct determination of CYP7A1 activity in hepatic biopsy is mostly not allowed for ethical reasons, so indirect methods are used with serum markers such as 7α-hydroxy-4-cholestene-3- one (C4). The first, methodical aim of the work was to convert the introduced HPLC method for the determination of C4 to LC-MS in order to increase the sensitivity. We focused on the solid phase extraction step, adjusting the composition and volumes of the washing and elution solution. By converting the method from HPLC to LC-MS, the sensitivity was increased approximately 7 times (LD = 1.39 ng/ml). In the second, clinical part of our work, we attempted to confirm the preliminary results of our laboratory on the distribution of C4 in lipoprotein fractions (LPP) in order to find parameter that would correlate with CYP7A1 activity better than C4 level itself. Preliminary results (performed in healthy individuals) showed that most of C4 is carried on HDL, and that the C4 distribution within LPP fractions is similar among examined subjects. We repeated the...
Regulation of cholesterol metabolism in hepatocytes
Ziková, Kateřina ; Vlachová, Miluše (advisor) ; Zlatohlávek, Lukáš (referee)
This thesis summarizes current data about cholesterol metabolism and its regulation in the liver. First part describes cholesterol transport among tissues by lipoproteins. Second part of this work deals with description of metabolic pathways of cholesterol conversion - how the cells obtain and metabolise cholesterol. Almost all cells can synthesize cholesterol or take it up from the circulation. The cells dispose of abundant cholesterol by several mechanisms - they convert cholesterol to cholesteryl esters that can be stored in lipid droplets; they turn cholesterol into oxysterols that can escape easier from the cell; or they export cholesterol through ATP-binding cassette (ABC) transporters. Specialized tissues (adrenal, gonads) transform cholesterol to steroid hormones. However, only the liver can remove cholesterol from the body in physiologically significant amount - it secretes cholesterol into the bile either directly or after conversion to bile acids. Third section deals with regulation of cholesterol metabolism in hepatocyte. Three transcription factors - sterol regulatory element binding protein (SREBP), liver X receptor (LXR), and farnesoid X receptor (FXR) - play the main role in regulation. Their activities are determined by concentration of cellular cholesterol or its metabolites -...
Students' Awareness about the Nutritional Value of Fats
Hlaváčková, Zuzana ; Marádová, Eva (advisor) ; Vodáková, Jitka (referee)
Bachelor theses is concerned with the fats in terms of nutrition, where fats are regarded as one of the basic nutrients in human nutrition. Specifically, is concerned with the characteristics of fats, their technological processing and importance in human boarding. Detail is focused on finding specific knowledge about fats among selected adults. The aim of this work is to clarify the extent to which selected adult overview of fats and what have the knowledge, which in turn can use in your everyday life when choosing foods and preparing meals. At the same time also to provide input for knowledge of fats, which are subsequently used in further work, which will focus on a different target group namely students from secondary schools and grammar schools. Keywords Fats, nutrition, margarine, fatty acids, cholesterol
Effect of cholesterol depletion on signalling cascade initiated with receptors coupled to G protein class Gq/G11
Ostašov, Pavel ; Svoboda, Petr (advisor) ; Teisinger, Jan (referee) ; Hof, Martin (referee)
Membrane domains are an important structure in plasamatic membrane. They concentrate various signaling molecules. Their main structural component is cholesterol and by its removal the membrane domains are disrupted. The aim of our work was to examine the effect of cholesterol depeletion on signaling initiated thyreothropin releasing hormone (TRH). Although its signaling cascade is located within membrane domains the receptor itself is not. We showed that cholesterol depletion by -cyclodextrin caused release of Gq/11 proteins and caveolin 2 from membrane domains. We also discovered that cholesterol depletion decreases potency of TRH to activate G proteins as well as induction of release of intracellular Ca2+ In the last part we investigated the effect of disruption of the cell membrane integrity by cholesterol depletion on thyrotropin-releasing hormone receptor (TRH-R) surface mobility and internalization in HEK293 cells stably expressing TRH-R-eGFP fusion protein. CLSM studies indicated that the internalization of receptor molecules initiated by TRH stimulation was significantly attenuated. The detailed analysis of recovery of TRH-R-eGFP fluorescence in bleached spots of different sizes indicated that cholesterol depletion results in an increase of overall receptor mobility. We suggest that migration of...
Incorporation of small organic hydrophilic substances into vesicular systems
Janoušková, Vendula ; Krouská, Jitka (referee) ; Mravec, Filip (advisor)
This bachelor thesis deals with the study of the encapsulation efficiency of hydrophilic drugs and their releasing from the aqueous core depending on the different composition of the components of individual liposomal systems. The hydrophilic fluorescent probe called pyranine was chosen as a model drug. The aim was to prepare liposomes which would be suitable for inhalation administration in terms of their properties. These liposomes would provide passive targeting with prolonged release time without causing negative side effects on the organism. We have succeeded in developing a standard operating procedure for the incorporation of hydrophilic drugs. Liposomal systems have been prepared consisting of the addition of various components as cholesterol, phosphatidic acid, pegylated phosphatidylethanolamine and trimethylchitosan. Furthermore, we were able to characterize the individual liposomal systems in terms of size, stability and encapsulation efficiency which are important physicochemical properties for further application potential.

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