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Echocardiographic assessment of left ventricular systolic function in rats adapted to hypoxia and exercise training
Hrdlička, Jaroslav ; Papoušek, František (advisor) ; Vybíral, Stanislav (referee)
- 4 - Abstract Adaptation to hypoxia or exercise training has cardioprotective effects against acute ischemic injury, but can potentially negatively influence heart function. Possible negative changes depend on the degree of hypoxia and exercise training intensity. It is therefore necessary to evaluate the effects of the specific adaptation protocols used. The ideal technique is echocardiography, which enables non-invasive, repeated and long-term measurements of the same individual allowing to study the development of changes in the course of adaptation. The aim of this study was to determine the effects of selected protocols of adaptation to intermittent hypobaric hypoxia (corresponding to the altitude of 4,000 to 8,000 meters above sea level, for 15 weeks in total) and exercise training (running speed 30 m.min-1 for 60 min a day, 4 weeks in total) on the left ventricle geometry and systolic function in rats. We assessed basic echocardiographic parameters of the ventricle geometry and function such as fractional shortening, ejection fraction, stroke volume, cardiac output etc. The adaptation of rats to intermittent hypobaric hypoxia lead neither to the impairment of systolic function nor to the development of left ventricle hypertrophy compared to controls; signs of moderate hypertrophy were observed only...
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Effect of stress on expression of 11β-hydroxysteroid dehydrogenase in rat brain
Kuželová, Andrea ; Pácha, Jiří (advisor) ; Vybíral, Stanislav (referee)
This thesis examines the influence of stress on the activity of hippocampal CA1 area. The main task was to determine whether the stress load affects the changes of the local metabolism of glucocorticoids, and whether the levels of corticosteroid receptors in the CA1 hippocampus are modulated in response to stress. In order to answer these questions, the experiments were carried out using three different rat strains - Fisher, Lewis and Wistar which differ in their activities of hypothalamic-pituitary-adrenal axis. Our results demonstrate that stress has no effect on expression of MR mRNA. Conversely, stress reduces the levels of GR mRNA in CA1 area of the dorsal hippocampus. Moreover, we confirmed that the Lewis and Wistar rats didn't change metabolism of glucocorticoids after stress response. By the Fisher rats increased levels of 11β-HSD1 mRNA expression and therefore increased the metabolism of corticosterone.
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Effect of stress on corticosteroid metabolism in peripheral tissues
Makal, Jakub ; Pácha, Jiří (advisor) ; Vybíral, Stanislav (referee)
Stressor influence can lead to homeostatic disruption. To eliminate this threat, mechanism which compensates negative effects of stressor was evolved by organisms. It's called stress response. One of two major systems that moderate stress response of organism is hypothalamic- pituitary-adrenal axis (HPA axis). Effectors of the HPA axis are glucocorticoids, steroid hormones secreted from adrenal glands. Enzymes which metabolize glucocorticoids are located in target tissues for these hormones. They convert active glucocorticoids into their inactive forms, or vice versa. Untill now, two such enzymes have been described - 11beta-hydroxysteroid dehydrogenases type 1 and type 2. It was proved that expression and activity of these enzymes can change under the influence of stressor. These changes are tissue-specific and dependent on type of applied stressor.
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Characterization of CART peptide analogs in vitro and in vivo
Nagelová, Veronika ; Maletínská, Lenka (advisor) ; Vybíral, Stanislav (referee)
Peptide CART (cocaine- and amphetamine- regulated transcript) is a neuropeptide acting in the hypothalamus to reduce food intake (anorexigenic peptide). Despite all efforts the receptor and the mechanism of action is still unknown. This peptide has two biologically active forms, CART(55-102) and CART(61-102). Peptide CART is able to bind to pheochromocytoma cells PC12. PC12 cells differentiated in neuronal phenotype with NGF (nerve growth factor) showed a higher number of binding sites (11250 ± 2520 binding sites/cell) compared to undifferentiated cells (3600 ± 570 binding sites/cell). PC12 cells differentiated by dexamethasone to chromaffin cells showed high non-specific binding. Peptide CART contains three disulfide bridges. To clarify the importance of each disulfide bridge to maintain biological activity, analogues with one (analogue 3, 4 and 5) or two (2, 6, 7 and 8) disulfide bridges and a peptide analogue of CART (61-102), which has methionin at position 67 replaced with norleucine were synthesized. We showed that biological activity was unchanged at analogue 1 and analogue 7 containing disulfide bridges in positions 74-94 and 88-101. When investigating cell signaling in PC12 cells, we tested if peptide CART activate of c-Fos, c-Jun, phosphorylated ERK1/2, CREB, JNK and p38. CART peptide...
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Obesity its causes and cosequences
Ondráčková, Anna ; Vybíral, Stanislav (advisor) ; Kuda, Ondřej (referee)
Obesity is one of the most common health problems in the Word. Over 500 million adults and over 40 million children are obese. The aim of this work is to summarize findings of causes and consequences of this health problem. Even though in some cases only genetic mutations are responsible for obesity for example mutation in ob gene or Prader-Willi syndrome most cases are caused by lifestyle of people -excessive food intake and insufficient physical activity. There are many health problems accompanying obesity. The most serious problems are metabolic syndrome, diabetes mellitus, cardiovascular diseases and cancer. The consequences of obesity are, however, not confined only to health. We can also observe the economic consequences. Financial cost of treatment of obesity and related diseases are estimated in billions of dollars. Pharmacological treatment has so far proved to be ineffective. If drugs are effective, the side effects are so severe that their use is not possible. So far, the adipose tissue hormones that regulate food intake provide the best hope.
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Metabolic effects of chronic metformin administration in obese mice depending on the composition of high-fat diet
Roubalová, Jana ; Rossmeisl, Martin (advisor) ; Vybíral, Stanislav (referee)
Obesity leads to many severe metabolic disorders, e.g. dyslipidemia, insulin resistance, ectopic fat accumulation in the liver and skeletal muscles, non-alcoholic fatty liver disease and finally diabetes mellitus type 2. Metformin (1,1-dimethylbiguanide) is the most favored medicament for the treatment and prevention of these disorders. It stimulates cellular glucose uptake and normalizes blood levels of lipid metabolites without triggering insulin secretion. Research on insulin resistance and diabetes is often realized through developing diet- induced obesity in laboratory animals. The aim of this project is to compare metabolic effects of two different high-fat diets named HFD and HSD. The HFD diet consists chiefly of n-6 polyunsaturated fatty acids (corn oil) and starch (100% glucose). The HSD diet contains mainly saturated fatty acids (lard) and sucrose (50% glucose and 50% fructose). I also studied metabolic effects of metformin by adding it continuously to the drinking water given to obese mice fed with the HFD or the HSD diet. Methods: Intraperitoneal glucose tolerance test (IPGTT), blood and tissue levels of lipid metabolites assessment, radio-immunological assessment of blood levels of insulin, assessment of AMPK activity in liver by western blotting. Results: Increased consumption of the...
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Microclimatic characteristics of natural and synanthropic roosts of dendrophilous and crevice-dwelling bats.
Nodžáková, Kateřina ; Vybíral, Stanislav (advisor) ; Benda, Petr (referee)
This study has tested microclimatic characteristics of natural and synanthropic roosts in the Trebonsko Biosphere Reserve - an important area in South Bohemia. Using a data logger, we measured the temperature in cavities used and unused by bats and compared them with temperature in artificial roost - window shutter and limekiln. Our results provide direct evidence that limekiln and cavities are occupied by different species of bats in comparison with window shutter and we contend that selecting microclimatic conditions of roosts are species-specific. Using limekiln may be more advantageous to bats than tree cavities, especially during pregnancy and lactation, since it provides suitable microclimate for roosting. This may be one of the factors associated with aggregation of maternity colonies during gestation period. Further we measured metabolic rate (oxygen consumption) in various temperatures of surroundings. Following species were taken into experiments: Eptesicus serotinus and Nyctalus noctula. The temperature interval was 26 - 43 řC. Our results confirmed different demands on microclimatic conditions in both species. We hypothesize that high roost temperatures within the thermal neutral zone enables bats to maintain body temperature passively thereby minimize energetic costs.
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