National Repository of Grey Literature 28 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Metabolism of cabozantinib by enzymes of first phase of biotransformation
Jurečka, Tomáš ; Indra, Radek (advisor) ; Kubíčková, Božena (referee)
Cabozantinib is an anticancer drug that inhibit tyrosine kinases which allow signal pathways important for growth and development of tumors. It is used for treatment of medullary thyroid cancer, hepatocellular carcinoma and kidney cancer. The major enzymes of the first phase of biotransformation that metabolize cabozantinib are cytochromes P450. In this thesis it was studied metabolism of cabozantinib and cytochromes P450 that participated on this metabolism. Hepatic microsomes of rat, mouse and rabbit were used for studying metabolism of cabozantinib in this thesis. It was also focused on the impact of particular isoforms of cytochromes P450 on metabolism of cabozantinib in rat microsomes. Time dependence of cabozantinib conversion in hepatic rat microsomes was also studied. Enzyme kinetics of metabolism of cabozantinib in hepatic rat microsomes, as well as impact of cytochromes P450 inhibitors on the metabolism were included. Metabolites were analyzed by high performance liquid chromatography (HPLC) and mass spectrometry. Formation of metabolites of cabozantinib increased over time to 30 minutes of incubation and with some others to 40 minutes of incubation. Up to five different metabolites were detected in experiments (M1, desmethyl cabozantinib, M3, monohydroxy cabozantinib and cabozantinib...
Study of interaction of dihydromyricetin and alcohol in vivo
Vargová, Silvia ; Hodek, Petr (advisor) ; Kubíčková, Božena (referee)
- Abstrakt Dihydromyricetin (DHM), also known as ampelopsin, is a natural antioxidant found in the plant Ampelopsis grossedentata, traditionally used in Chinese medicine. Dihydromyricetin exhibits health-benefiting activities. Besides its antioxidative, anti-inflammatory, anticancer, and antimicrobial effects, it is said to suppress intoxication by alcohol and mitigate the symptoms of hangover and abstention. The mechanism of the activity of DHM on the metabolism of ethanol has not been fully explored. Thus, the focal point of the presented thesis was to explore the effect of DHM on the expression of CYP2E1, one of the major enzymes participating in the metabolism of ethanol in organisms. Male rats were administered with ethanol (EtOH) or ethanol in combination with DHM, and the EtOH concentration of the blood was determined. The amount of EtOH and acetaldehyde in the blood of individuals indicates that DHM does not affect the rate of EtOH metabolism. Subsequently, the effect of DHM on repeated premedication of EtOH was monitored. The group of rats treated with DHM showed a slower metabolism of EtOH than the group solely premedicated with EtOH. Ultimately, the effect of DHM on CYP2E1 expression was studied. Microsomal fractions were prepared from the rat livers. By use of Western blotting with a...
Metabolism of inhibitors of tyrosine kinases, the drugs of new generation
Čillíková, Olívia ; Indra, Radek (advisor) ; Kubíčková, Božena (referee)
Cancer is the second major cause of death after heart-attack in the world. In recent years, research has focused on tyrosine kinase inhibitors (TKIs) as part of targeted chemotherapeutic treatment. Vandetanib is a TKI affecting epidermal growth factor receptor (EGFR), rearrangement during transfection (RET) and vascular endothelial growth factor receptor 2 (VEGFR2). It is primary used for treatment of medullary thyroid cancer. Vandetanib is biotransformed by cytochromes P450 and flavin monooxygenases in human organism. Cytochromes P450 (CYPs) oxidaze vandetanib to only one metabolite, N-desmethyl vandetanib, which exhibits similar efficiency as parental molecule. NADPH is the major cofactor of reaction cycle of CYPs. This bachelor thesis studies the effect of various types of cofactors and pH on oxidation of vandetanib by selected human recombinant cytochromes P450, namely CYP2C8 coexpressed with cyt b5, CYP2D6, CYP3A4 and CYP3A4 coexpressed with cyt b5. Here, we investigate the effect of cofactors NADPH, NADH and their mixture in a 1:1 ratio on the amount of N- desmethyl vandetanib formed during the biotransformation of vandetanib. The effect of pH on the oxidation of vandetanib by CYP 3A4 and CYP 3A4 + b5 was also analysed. We analysed the amount of the metabolite formed at the pH range 7 to 8.5...
Biochemical characterization of tomato plants infected with fungal pathogens
Oušková, Marie ; Hýsková, Veronika (advisor) ; Kubíčková, Božena (referee)
Fungal pathogens including Verticillium longisporum which causes verticillium wilt are among the serious diseases of crops that easily spread worldwide. One of the ways to prevent fungal infection is to use fungal biocontrol agents applied as a seed coating. This control agent, the non-pathogenic oomycete Pythium oligandrum, enters the soil together with the seed and acts symbiotically in the plant's root system. On the one hand, it stimulates the plant's defence mechanism by secreting elicitors, and on the other hand, by providing tryptamine, it stimulates growth and increases the plant's fitness with auxin. In this work we studied the effect of seed treatment of Solanum lycopersicum L. cv. Micro-Tom with three different isolates of the genus Pythium (including the commercially used isolate M1 and two yet unused isolates X42 and X48) on the activities of antioxidant and NADP(H)-dependent enzymes in the leaves of plants infected with fungal pathogen V. longisporum. Two weeks after pathogen inoculation, no significant difference was found in the studied enzymes except for increased glucose-6phosphate dehydrogenase and NADP-malate dehydrogenase (oxaloacetate decarboxylation) activity in plants treated with X42 isolate and increased shikimate dehydrogenase activity and antioxidant capacity in plants...
Study of enzymes secreted by oomycete Pythium oligandrum
Hrdinová, Karolína ; Ryšlavá, Helena (advisor) ; Kubíčková, Božena (referee)
Pythium oligandrum is one of the non-pathogenic microorganisms of Pythium species which found its use as biological control agent. The main modes of action of this oomycete lie in inducing the plant immunity and in mycoparasitism of pathogenic fungi and fungus-like organisms. The oomycete attacks the pathogens by secretion of hydrolytic enzymes into the environment. In the first part of this bachelor's thesis, activity of hydrolytic enzymes endo-1,3-β-glucanase, cellulase, chitinase and proteases was observed in a commercial product based on Pythium oligandrum, called Polyversum-Biogarden. It was conclu- ded that the direct hydrolysis of phytopathogens is probably not the main mechanism of this product because the activity of glycosidases increased only after six hour-long incubation of the Polyversum-Biogarden in water and the proteolytic activity was not detected. In the second part of the bachelor's thesis, properties of proteases secreted by orga- nism Pythium oligandrum were studied. The highest proteolytic activity was observed at pH 6,5. Ovomucoid acted as an inhibitor of secreted proteases. The stability of pro- teases was lowered by SDS, detergents present in liquid soaps and by a solution of a solid soap or NaOH. Only the highest concentrations of urea lowered the activity of proteases....
Antibody against bacterial lectins as a tool preventing lung infections of cystic fibrosis patients
Bolshova, Arina ; Hodek, Petr (advisor) ; Kubíčková, Božena (referee)
Cystic fibrosis is an autosomal recessive disease that is caused by mutation of the CFTR protein ("cystic fibrosis transmembrane conductance regulator"). The CFTR protein is an ion channel for chloride and bicarbonate ions transmission. This defect leads to the formation of dense mucus in lungs that causing breathing problems and chronic bacterial infections. Passive immunization by administering chicken antibodies produced against pathogen can be used as a prophylaxis for patients with cystic fibrosis. Immunoglobulins Y reduce adhesion of bacteria to lung epithelial cells and prevent infection. This strategy is a good alternative to classical antibiotic therapy because it targets the pathogen and doesn't affect normal bacterial microflora. At first the chicken antibodies produced after immunization of the experimental hen by Burkholderia cenocepacia lectin (BC2L-A) were isolated and further purified on an affinity column with covalently bound lectin. The affinity purified fraction was 9 times concentrated compared to original fraction as far as the content of the specific anti-lectin antibody is concerned. The amount of affinity purificated antibodies is approx. 0.2% of the total isolated immunoglobulins. Their immunoreactivity has been verified using recombinant lectin and the lectin produced by...
Structural biology of receptor NKp44 and its ligand PCNA
Herynek, Štěpán ; Vaněk, Ondřej (advisor) ; Kubíčková, Božena (referee)
Natural killer cells (NK cells) are part of the immune system in human and other mammals. The task of these cells, which belong to the non-specific immunity, is to induce apoptosis in other cells of the body that may represent a threat for the body (i.e., tumour or virally infected cells). NK cells have a variety of surface receptors to recognize their target cells. A number of receptors are well-known today and they may be divided into groups based, e.g., on their structural similarities or on the type of signal which these receptors present to NK cells. Accordingly, we distinguish activation and inhibitory receptors. Inhibitory receptors inhibit NK cell response, while activation receptors elicit this response. During NK cell contact with another cell, the resulting NK cell behaviour is always the result of a certain balance of activation and inhibitory receptor responses. The NKp44 receptor is an immunoglobulin-like receptor. This receptor is very unique among other receptors in many respects, for example because it is associated with both activation and inhibitory motif. The ligand of this receptor is a proliferating cell nuclear antigen (PCNA). PCNA is a clamp protein important, inter alia, during DNA replication, in which it anchors other replisome proteins. This work is focused on...
Recombinant expression of protein NKp46 and its ligand Epa1
Houserová, Jana ; Vaněk, Ondřej (advisor) ; Kubíčková, Božena (referee)
Natural killer cells (NK cells) are cells of innate immunity that play an essential role in the immune response of an organism. In contact with infected, stressed or tumour cells, the NK cells can trigger cytotoxic mechanisms. The initiation of mechanisms depends on the presence of activating or inhibitory ligands on the surface of the cells. On the surface of the NK cells, there are activating and inhibiting receptors that upon binding their respective ligands send a signal to the NK cell. One of the activating mechanisms is the decrease of expression in MHC gp I molecules on the surface of the infected cells. This molecule is a ligand of the inhibiting receptors. One of the activating receptors of NK cells is NKp46. This receptor belongs to the natural cytotoxicity receptor (NCR) family. NKp46 has many ligands, one of them being the adhesin Epa1 of yeast Candida glabrata. This thesis aims at preparing plasmids and producing extracellular domains of the NKp46 receptor and its ligand adhesin Epa1.The interaction of NKp46 and its ligand Epa1 remains to be the subject of future research. Plasmids containing NKp46 and Epa1 genes were successfully prepared and verified by DNA sequencing. The NKp46 protein was produced in eukaryotic expression system of HEK293S GnTI- cell line. A stably transfected...
Role of gut microflora in metabolism of drugs and carcinogens
Hucková, Pavlína ; Hodek, Petr (advisor) ; Kubíčková, Božena (referee)
We can consider intestinal microflora as another large organ of human body, that isn't sufficiently explored yet. It is very complex system with many functions for host organism. It contains a large number of bacteria, viruses and archea. Intestinal microflora has an important function on food decomposition and metabolism of foreign substances. Foreign substances has a positive or negative effect on intestinal bacteria. That's why the research focuses on metabolism of these substances and their effect on digestive tract disease. Research also focus at intestinal bacteria diversity which may be important in treating patients. Fecal samples (A, B, C) was incubated at time 0, 3 and 6 hours in two mediums (McDougall buffer and BHI medium). Incubated samples was analyzed by RP-HPLC method. Focus was on degradation of myricetin and his potential transformation into dihydromyricetin. Research proved, that degradation myricetin in 6 hours was at every fecal sample (A, B, C). It can not be evaluated what medium is best for the bacteria because in first fecal sample (A) there was a faster degradation myricetin in McDougallov's buffer then in BHI medium. Another sample (B) on the others side reacted faster in BHI medium then in McDougallov's buffer. The last sample (C) occured practically same degradation for...

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5 KUBIČKOVÁ, Barbora
5 Kubičková, Barbora
5 Kubíčková, Barbora
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