National Repository of Grey Literature 82 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Mechanisms of resistance and iron metabolism in cancer stem cells
Lettlová, Sandra ; Truksa, Jaroslav (advisor) ; Kovář, Jan (referee) ; Brábek, Jan (referee)
(EN) Analogously to normal stem cells within the tissues, cancer stem cells (CSCs) have been proposed to be responsible for maintenance and growth of tumours. CSCs represent a small fraction of cells within the tumour, which is characterised by self-renewal capacity and ability to give rise to a tumour when grafted into immunocompromised mice. Cells with increased stemness properties are believed to be responsible for tumour resistance, metastases formation and relapse after tumour treatment. The first part of this work concentrates on resistance of the tumours, which is often associated with increased expression of ATP-binding cassete (ABC) transporters pumping chemotherapeutics out of the cells. For the purposes of this study, we utilized an in vitro model of CSCs, based on cultivation of cells as 3D "spheres". Expression profiling demonstrates that our model of CSCs derived from breast and prostate cancer cell lines express higher mRNA level of ABC transporters, particularly ABCA1, ABCA3, ABCA5, ABCA12, ABCA13, ABCB7, ABCB9, ABCB10, ABCC1, ABCC2, ABCC3, ABCC5, ABCC8, ABCC10, ABCC11 and ABCG2 among the cell lines tested. The protein level of ABC transporters tested in breast CSCs showed higher expression of ABCB8, ABCC1, ABCC2, ABCC10 and ABCG2 but downregulation of ABCB10 and ABCF2 proteins....
Molecular mechanisms of apoptosis induction by taxanes in breast cancer cells
Jelínek, Michael ; Kovář, Jan (advisor) ; Brábek, Jan (referee) ; Reiniš, Milan (referee)
Taxanes are cytostatic routinely used for the treatment of solid breast, ovarian, prostate, head and neck tumors and other types of tumors. Resistance of tumor cells to the effect of taxanes represents serious obstacle for the employment of taxanes in the treatment of tumors. This resistance can be associated, among other things, with lower rate of apoptosis induction in cancer cells or also with increased level of transporters transporting taxanes out of the cell. In this PhD thesis we tried: (1) to contribute to elucidation of the role of molecular mechanisms of apoptosis induction by taxanes in cells of human breast cancer. Specifically, it meant to contribute to elucidation of the role of initiator caspase -8 a - 9 and mainly of initiator caspase-2. Next, to contribute to elucidation of the role of executioner caspase -3 - 6, and -7 and selected proteins of the Bcl-2 family. (2) To contribute to elucidation of molecular mechanisms of resistance of human breast cancer cells to taxanes. Specifically, it meant to describe the role of selected functional groups in taxane structure in bringing about and overcoming resistance to taxane and next to contribute to elucidation of the role of P-glycoprotein (ABCB1 transporter) in the resistance to individual taxanes. 1) We found that caspase-2 represents...
Mechanisms of apoptosis induction and inhibition by fatty acids in pancreatic β-cells
Šrámek, Jan ; Kovář, Jan (advisor) ; Brunerová, Ludmila (referee) ; Šeda, Ondřej (referee)
Recently, diabetes mellitus type 2 (DMT2) represents one of the most important metabolic diseases according to its incidence and economic impacts. One of the main reasons of this diesease is loss of function and viability of pancreatic β-cells due to the effect of increased levels of saturated fatty acids (FAs). Unsaturated FAs are better tolerated by β-cells. They are even capable of inhibiting detrimental effects of saturated FAs. Molecular mechanisms of apoptosis induction in pancreatic β-cells by saturated FAs as well as mechanisms of inhibition of this induction by unsaturated FAs are not completely elucidated. The main aim of this study was to contribute to elucidation of these mechanisms. Concerning human pancreatic β-cell line NES2Y we demonstarted: (1) Activation of caspase-2 by stearic acid (SA), in apoptosis inducing concentration (1 mM), is not crucial for the process of apoptosis induction. However, this caspase modulates SA-induced endoplasmic reticulum (ER) stress pathways. (2) SA (1 mM) activates the p38 MAPK signaling pathway and inhibits the ERK signaling pathway. Inhibition of the ERK signaling pathway is probably a consequance of the p38 MAPK pathway activation. However, p38 MAPK is not very likely crutial for the apoptosis induction by SA. Unsaturated oleic acid (OA, 0.2 mM) is able to...
Detection of car approach speed using camera imge processing
Kovář, Jan ; Číka, Petr (referee) ; Šmirg, Ondřej (advisor)
The thesis deals with digital image processing, from the initial acquisition of digital picture frames, subsequent processing segmentation and algorithms to detect visual shapes on the scene. Image processing is a very broad topic, so here are analyzed for more understanding of the fundamental principles of perception and processing of video signals, image representation, his starting shooting through filters governing digital image processing methods to detect the objects in an image. It is also demonstrated by the size dependence of the object in the image on the distance from the camera, whereby we can determine the speed of approaching or moving away from the object. We will show you the specific determination of the distance we need to know the actual result size of the object. This is because the ratio between the size of the object depending on the distance is the same for each object. Finally, this work presents the resulting image frames for implementation using OpenCV library.
Molecular mechanisms of apoptosis induction in tumor cells
Koc, Michal ; Kovář, Jan (advisor) ; Červinka, Miroslav (referee) ; Haškovec, Cedrick (referee)
V. Závěr Tato práce se zaměřila na studium procesů uplatňujících se v indukci apoptosy různými faktory. V našem případě jsme indukovali buněčnou smrt u nádorových buněk deprivací železa, klinicky používanými taxany (paclitaxel, docetaxel) a nově syntetisovanými fotosensitivními látkami. Z presentovaných publikací jsme získali tyto závěry. (1) Studie týkající se indukce apoptosy deprivací železa prokázaly účast odlišných signálních drah vedoucí k indukci apoptosy u myších a lidských nádorových buněk. V obou případech byla použita B lymfomová buněčná linie citlivá k deprivaci železa. U myších buněk jsme popsali významnou část apoptotické signální dráhy u 38C13 buněk sensitivních k indukci apoptosy deprivací železa. Deprivace železa u těchto buněk vede k translokaci proapoptotického proteinu Bax z cytosolu na mitochondrie, která je následována zhroucením mitochondriálního membránového potenciálu v důsledku porušení integrity vnější mitochondriální membrány, uvolněním cytochromu c z mitochondrií, aktivací kaspasy 9 a následnou aktivací kaspasy 3. U lidských buněk jsme taktéž zaznamenali indukci apoptosy deprivací železa, avšak charakterem mechanismu odlišnou od apoptosy popsané u myších 38C13 buněk. V případě lidských Raji buněk sensitivních k indukci apoptosy deprivací železa docházelo pouze k aktivaci kaspasy...
Regulation of triglyceride metabolism in circulation in postprandial phase.
Zemánková, Kateřina ; Kovář, Jan (advisor) ; Kazdová, Ludmila (referee) ; Zlatohlávek, Lukáš (referee)
Increased triglyceride (TG) concentration has been generally accepted as a risk factor for ischemic heart disease and, therefore, lowering TG is therapeutic target that should reduce cardiovascular disease risk. Traditionally, concentration of TG is measured in the fasting state (8-12 hours after an overnight fasting) mainly because the rise in TG levels after meal leads to the high variation in TG values. However, human beings spend larger portion of the day in a postprandial state and postprandial hypertriglyceridemia may then play a substantial role in determination of cardiovascular disease risk. The increased and prolonged postprandial lipemia has been found in patients with coronary heart disease. Moreover, recent data from Copenhagen Heart Study point out that the non-fasting TG concentration is associated with cardiovascular disease risk more tightly than the fasting TG concentration. Importantly, concentration of non-fasting TG is substantially affected by individual behavioural habits such as diet composition and physical activity. It remains to be determined whether it would be appropriate to identify individuals at higher risk of cardiovascular disease due to increased postprandial TG using tolerance test analogous to glucose tolerance test. The protocol of standardized fat tolerance...

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