National Repository of Grey Literature 41 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Biological effects of edible algae.
Vaňková, Kateřina
Nutritional factors with antioxidant properties, such as those contained in edible algae or green plants, might be implicated in protection against cancer development. Chlorophyll and other tetrapyrrolic compounds, structurally related to heme and antioxidant bile pigment bilirubin, belong to important candidate molecules, which might be responsible for these effects. Based on our studies demonstrating antiproliferative effects of S. platensis edible alga extract on experimental model of human pancreatic adenocarcinoma we investigated in detail the effect of chlorophyll occurring abundantly in this alga. Since only scarce data exist on the antiproliferative effects of chlorophylls, the aim of our study was to assess these effects. The study was performed on experimental models of human pancreatic and prostate cancer. The inhibitory effects of chlorophylls (chlorophyll a, chlorophyll b, chlorophyllin and pheophytin a) on cell proliferation and cell viability were investigated in in vitro studies. Chlorophylls reduced the mRNA expression as well as activity of hemeoxygenase in tested pancreatic cancer cells. Simultaneously, chlorophylls played an important role in redox environment of studied cancer cell lines including modulation of mitochondrial membrane potential, reactive oxygen species (ROS)...
Myocardial tolerance to ischemia/reperfusion injury - possible protective mechanisms
Alánová, Petra
Ischemic heart disease is the leading cause of death and disability worldwide. The effects of ischemic heart disease are usually attributable to the detrimental effects of acute myocardial ischemia/reperfusion (I/R) injury. The aim of the thesis was to contribute to current effort to clarify the basis of mechanisms that could save the heart from I/R injury. The whole thesis is based on four studies; while the first three are published, the fourth one has been under revision. In the first study, we proved the involvement of nitric oxide (NO) in the cardioprotective mechanism of chronic hypoxia (CH). We described that exogenously increased availability of NO as well as inhibition of phosphodiesterase type 5 led to increased myocardial tolerance of normoxic and chronically hypoxic rats. The effects of both interventions were not additive, suggesting that NO is included in cardioprotective signaling of CH. Second study continued in investigating molecular mechanisms underlying cardioprotection induced by CH. We showed that infarct size-limiting effect of adaptation to CH was accompanied by increased myocardial concentration of tumor-necrosis factor alpha (TNF-α) and TNF-α receptor R2. In the third study, we examined the effect of dexrazoxane (DEX), the only clinically approved drug against...
Signaling effects of adenylate cyclase toxin action on phagocytes
Černý, Ondřej
The adenylate cyclase toxin (CyaA) plays a key role in the virulence of Bordetella pertussis. CyaA penetrates CR3-expressing phagocytes and catalyzes the uncontrolled conversion of cytosolic ATP to the key second messenger molecule cAMP. This paralyzes the capacity of neutrophils and macrophages to kill bacteria by oxidative burst and opsonophagocytic mechanisms. Here we show that CyaA suppresses the production of bactericidal reactive oxygen and nitrogen species in neutrophils and macrophages, respectively. The inhibition of reactive oxygen species (ROS) production is most-likely achieved by the combined PKA-dependent inhibition of PLC and Epac-dependent dysregulation of NADPH oxidase assembly. Activation of PKA or Epac interfered with fMLP-induced ROS production and the inhibition of PKA partially reversed the CyaA-mediated inhibition of ROS production. CyaA/cAMP signaling then inhibited DAG formation, while the PIP3 formation was not influenced. These results suggest that cAMP produced by CyaA influences the composition of target membranes. We further show here that cAMP signaling through the PKA pathway activates the tyrosine phosphatase SHP-1 and suppresses the production of reactive nitrogen species (RNS) in macrophages. Selective activation of PKA interfered with LPS- induced iNOS expression...
Changes in anatomy of coniferous needles in response to anthropogenic pollution
Štěpánová, Kristýna ; Albrechtová, Jana (advisor) ; Votrubová, Olga (referee)
The anatomical structure of conifer needles is affected by external enviromental conditions. From abiotic factors, apart of irradiation, main determining factors are drought and extreme temperatures belonging to factors of climate change. Anthropogenic pollution has a significant position among the external abiotic factors that cause changes in the structure of needles. At present, the main polluting compounds are tropospheric ozone, SO2, NOx and PM. Due to the effect of atmospheric pollutants, the proportion of individual tissues in the needle changes, so does the proportion of intercellular spaces and the internal structure of cellular organelles, especially chloroplasts. Mesophyll cells show signs of degradation, especially around the substomatal cavity. There appears a visible damage on the needle surface - chloroses and necroses. The process of senescence speeds up during the activity of stress enviromental factors, such as anthropogenic pollution. The main objective of the present Thesis is to gather knowledge about changes of conifer needle structure, caused by anthropogenic pollution, especially ozone, SO2 and NOx, in combination with climate change factors - drought and extreme temperatures. The review is focused on modifications on various anatomic hierarchical levels, from visible...
Effect of dihydromyricetin on hepatic ethanol metabolism
Boubínová, Gabriela ; Hodek, Petr (advisor) ; Bebová, Michaela (referee)
Dihydromyricetin (DMH) is a natural flavonoid compound with positive effects on the human organism. In traditional Chinese medicine, plants containing DMH were used to treat liver diseases and to reduce alcohol intoxication. The effects of DHM on ethanol metabolism are not yet completely understood. Effects of DHM during alcohol intoxication were studied on primary hepatocytes of rats. DCFDA and DHR probes were used to prove that DHM (depending on concentration) reduces the number of reactive oxygen and nitrogen species in primary hepatocytes. However, the hepatoprotective effects of DHM were not achieved when presence of the alanine aminotransferase (ALT) was used to measure the damage of cells exposed to alcohol. Further, the effects of DHM on alcohol metabolism were studied in vivo. Rats were administered with single dose of ethanol or ethanol combined with DHM. Measured blood levels of ethanol and acetaldehyde show that DHM has no effects on the rate or levels of alcohol metabolism. The effects of DHM were also studied with repeated alcohol administration. In the group that was administered also DHM, increased blood levels of ethanol were measured. This points that DHM slow down the metabolic rate of ethanol. Obtained results did not prove any positive effects of DHM on alcohol metabolism....
The role of NADPH oxidase in architecture and function of β cells and Langerhans Islets
Tučková, Štěpánka ; Plecitá, Lydie (advisor) ; Bardová, Kristina (referee)
Local production of reactive oxygen species (ROS) and changes in the redox environment influence the metabolism and function of β cells of the Langerhans islets (LO). Changing the ratio between NAD(P)H / NAD(P)+ redox partners significantly affects sensitive proteins and ROS production. ROS are able to reversibly modify some amino acid residues (eg Cys, Met) of antioxidant enzymes and their interaction partners. Such a signaling cascade allows the transmission of a signal over longer distances and can also interfere with the influence of gene expression. The unique enzyme NADPH oxidase 4 (NOX4) is present on membranes within β cells and constitutively produces H2O2 depending on the presence of NAD(P)H. After glucose stimulation, both NAD(P)H and Nox4 mRNA levels increase. As previously observed in our laboratory, C57BL/6J mice with a specific Nox4 deletion in β cells have a disrupted biphasic insulin release and exhibit insulin resistance in fat and muscle tissue. We found that the absence of NOX4 in C57BL/6J mice affects LO architecture. Wildtype (WT) mice on a normal, predominantly carbohydrate diet (ND) have the majority of small LO with an area of up to 5 000 μm2 (measured on histological sections). High-fat diet (HFD) feeding of WT for 8 weeks leads to the development of diabetic phenotype and...
Oxidative stress in pathogenic amoebae
Plíva, Jan ; Šuťák, Róbert (advisor) ; Smutná, Tamara (referee)
Reactive oxygen species are substances that contain an atom of oxygen with an unpaired electron. This substance is highly reactive thanks to that unpaired electron. Organisms are capable of utilizing this reactivity in a lot of reactions. Cells can create reactive oxygen species as a by-product of aerobic respiration or by the action of enzymes such as NADPH oxidase. Reactive oxygen species play a crucial role in host defense against parasitic organisms. During host defense, parasitic organisms are destroyed by immune cells utilizing oxygen species. These reactions are in place also in the case of infection caused by pathogenic amoebae. Amoebae are eukaryotic unicellular organisms that are in some cases capable of causing serious illnesses. During the infections, amoebae must be able to bypass the host immune system, thus reactive oxygen species. This is accomplished by parasitic detoxification systems which helps pathogenic amoebae to overcome oxidative stress induced by reactive oxygen species. However, pathogenic amoebae are also capable of using reactive oxygen species to overcome the host immune system. This fact only confirms how tangled and complicated is the effect of reactive oxygen species during an interaction between the host organism and parasite.
Characterization and application of microwave plasma on wound healing
Truchlá, Darina ; Němcová, Andrea (referee) ; Krčma, František (advisor)
Non-thermal plasma has a lot of ways for using in nowadays medicine. It presents many useful actions like charged particles, UV light, electric field, radicals, excited atoms and molecules. That complicated chemistry directs to uncountable synergistic interaction between cold plasma and biological systems, involve cells and tissues. This thesis is about effects of cold plasma to wound healing. Two different microwave plasma systems were used for the presented study. The first one was argon plasma torch generated by surface wave using the quartz capillary, the second one was plasma torch with reverse vortex argon flow. Diagnostics of plasma jet by optical emission spectroscopy shown the presence of active particles, which are responsible for a lot of impact of plasma treatment. Concentrations of active particles generated by plasma are dependent on conditions of plasma generation like power of generator and gas flow. For visual evidence of effects on skin caused by active particles was created simulation of skin tissue. Interaction between plasma jet and artificial skin tissue shown that UV light and temperature are not responsible for all observed effects which are noticed after plasma treatment. Some part of experiments was realized in collaboration with Medical University of Sofia in Bulgaria. The theory of positive effect to wound healing was supported by experiments based on treating artificially created wounds on laboratory mice by cold plasma. It was proved, that process of wound healing is significantly shorter after using plasma treatment in comparison with normal wound healing. Plasma treating of wound for 10 seconds in two consequent days seems like more effectively than application of plasma only one day. This Thesis was carried out as a part of international project PLASMABORDER that was supported by European commission under cohesion funds; programme INTEREG SK-CZ under contract No. 304011P709.
Role of carbohydrate metabolism in defence against oxidative stress induced by arsenic
Kofroňová, Monika ; Lipavská, Helena (advisor) ; Száková, Jiřina (referee) ; Kovalíková, Zuzana (referee)
Heavy metal contamination significantly reduces crop yields, causing serious problems in agriculture and having a major impact on human health if these contaminants enter the food chain. Understanding the mechanisms of plant responses could help to increase their resistance to heavy metals as well as their potential use in phytoremediation. Carbohydrates play an important role in plant growth and development as well as in defense reactions. This work summarizes the results of four publications focused on the effects of arsenic and thorium on antioxidant mechanisms in tobacco plants and horseradish root crops. Attention is paid, among other things, to the dynamics of sugar contents, which are potentially important molecules involved in the fight against oxidative stress. The first publication summarizes arsenic effects on plant physiological parameters, focusing on arsenic tolerance-enhancing mechanisms as well as summarizing the ability of plants to cope with arsenic-induced oxidative and nitrosative stress. Emphasis was placed on, among other things, a topic that was unjustly neglected in previous publications - i.e. carbohydrate metabolism. Further work was already experimental and dealt with the study of arsenic as a trigger of oxidative stress in the root culture of horseradish and...
Influence of electrical pulses on human blood phagocytes
Chorvátová, Michaela ; Číž,, Milan (referee) ; Kubala,, Lukáš (advisor)
The phagocytic cells circulating in the bloodstream play a key role in both the defense of the body and the pathology of inflammatory diseases. Thus, targeting their functions has potential to modulate an immune response, especially during the inflammatory phase. This master's thesis was focused on the influence of electric pulses on the most abundant phagocyte population in human peripheral blood, namely neutrophils. The theoretical part describes the role of neutrophils in the development of the immune response and the effects of the electric field on various cells. Consequent part of the thesis was the optimization of the electrical stimulation of neutrophils using a unique platform with a network of gold electrodes. In stimulated cells by electrical pulses, activation of selected signaling pathways, degranulation, ROS production, citrullination of histone H3 and expression of surface markers were monitored. Overall, electrical stimulation was observed to induce neutrophil activation but only electrical pulses of size 1 V were found to be statistically significant in the case of ROS production and 10 mV and 100 mV electrical pulses in the case of metalloproteinase MMP8 degranulation. The absence of significant effects in the most observed parameters was probably due to unwanted activation of neutrophils in control samples.

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