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Synchronization of circadian system during prenatal and early postnatal development
Houdek, Pavel ; Sumová, Alena (advisor) ; Novotná, Růžena (referee)
One of the few attributes common to almost all living organisms is an ability to generate and maintain endogenous rhythms, which are controlled by a biological clock. The processes, which recur with a period of about 24 hours, are known as the circadian rhythms. The circadian clock controls rhythms of molecular, physiological as well as behavioral processes and adapts their activity to regularly appearing changes in day and night or season. In case of mammals, central oscillator is located in the hypothalamic suprachiasmatic nuclei (SCN). The SCN clock entrains rhythms of peripheral oscillators located in cells of other tissues. The central oscillator itself is synchronized with external environment mainly by a light-dark cycle, however, other cues can entrain the SCN clock as well. For example, during prenatal development, entrainment of a fetal clock is entirely dependent on non-photic cues derived from maternal organism. This study aimed to investigate a mechanism of the communication between the maternal and fetal central oscillators. A hypothesis was tested whether maternal melatonin may play a role in entrainment of the circadian clock in the fetal SCN. Furthermore, a mechanism, how melatonin may entrain the fetal clock was investigated at molecular level. The results provided evidence, that...
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Methods and consequences of some neurosurgical interventions in animal model and in human clinic. Pinealectomy and intracerebroventricular application.
Řezáčová, Lenka ; Tichý, Michal (advisor) ; Szárszoi, Ondrej (referee) ; Přibáň, Vladimír (referee)
Clinical surgical techniques of pinealectomy and intracerebroventricular (i.c.v) cannulation are still used in the clinic in indicated cases. In research, there is an effort to replace these classical surgical techniques by other means. However, these various new models often do not reflect the complexity of the functions taking place in the living organism as a whole. The thesis shows that these surgical techniques should be also a part of biomedical research in the future, as they still bring new important information. In the experiment, the pinealectomy can serve as a model of resection or depletion (removal of natural hormone secretion), while i.c.v. application of the active substance to the ventricles on the contrary as a model of addition or substitution. The practical part of the thesis is divided into 4 areas: A) pinealectomy - an animal models, B) pinealectomy - in the experiment, C) pinealectomy - in the clinical practice and D) intracerebroventricular application - in the experiment. The work describes in detail the surgical techniques and discuss possible consequences of pinealectomy in 6 animal species (and their comparison) and in humans. It also includes an experiment with pinealectomy in a rat and a clinical study in patients with pineal cyst and subsequent pinealectomy. The work...
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Pineal lesions: clinical presentation, hormone secretion, sleep quality and effect of surgical treatment
Májovský, Martin ; Netuka, David (advisor) ; Šonka, Karel (referee) ; Lipina, Radim (referee)
Introduction: Pineal region is a deep-seated part of the brain surrounded by highly eloquent structures. Differential diagnosis of space-occupying lesions in this region encompasses pineal gland cysts, pineal gland tumours, metastases, germ cell tumours, meningiomas, gliomas, hemangioblastomas and neuroectodermal tumours. In this thesis, I focused mainly on patients with pineal cysts, which is a benign affection of the human pineal gland on the borderline between pathology and normality. The clinical management of patients with a pineal cyst remains controversial, especially when patients present with non-specific symptoms. A melatonin secretion in patients with a pineal cyst before and after a pineal cyst resection has not been studied yet and the effect of surgery on human metabolism is unknown. Materials and Methods: We performed a prospective study between 2000 and 2016. All patients with a pineal cyst larger than 7 mm were included. Epidemiological data, presenting symptoms, surgical results and radiographic and clinical follow-up were documented. We examined melatonin, cortisol and blood glucose secretion profiles perioperatively in a subgroup of 4 patients. The control group was represented by 3 asymptomatic patients with a pineal cyst. For each patient, 24-h circadian secretion curves of...
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Evaluation of Biological Efficiency of Pilot Installation of Biodynamic Lighting in a Retirement Home
Halászová, Andrea ; Bendová, Zdeňka (advisor) ; Jelínková, Dana (referee)
Many actions we observe in nature show some kind of regularity, therefore we call them rhytms. Rhytms with a period of approximately 24 hours, so called circadian rhytms, can be distinguished in many physiological processes, with the sleep-wake cycle being one of the most prominent ones. Light is the main exogenous circadian synchronizator and thanks to the circadian rhytm influence on physiological function, it's also often spoken about an influence of light on the entire organism. Nowadays, when we spend most of the day indoors under artificial light, we often suffer from a lack of natural daylight and its synchronizing potential. This is even more prominent in elderly population living in nursing homes and in other social facilities. Lately, a new type of lighting, so called biodynamic, has been introduced. Biodynamic lighting can simulate changes in natural light conditions throughout the day and therefore partially compensate for the lack of natural daylight we suffer from, and also minimize risks of the night light. In this study we aimed to test changes in the circadian system of seniors living in the Retirement Home of TGM in Beroun using questionnaires and circadian markers. We have shown a positive effect of the installed biodynamic lighting on our participants' circadian markers and...
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The effect of evening exposure to blue light on sleep quality
Baumová, Nikola ; Šteffl, Michal (advisor) ; Bunc, Václav (referee)
Title: The effect of evening exposure to blue light on sleep quality Objective: The main aim of this bachalar thesis is to compare and determine the effect of exposure to blue light in the evening on the quality and parameters of sleep using the results obtained from previous studies dealing with evening exposure to blue light on sleep quality. Methods: The bachalar thesis was carried out as a systemastic review. The source of information were scientific articles and studies from the electronic database PubMed and scientific literature related to the issue. Results: Exposure to blue light in the evening decreased the quality and parameters of sleep. These negative effects were eliminated by using blue light blocking glasses. Keywords: Blue light, sleep, blue light blocking glasses, melatonin
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Determination of tryptophan, serotonine and melatonin in plants by using HPLC
Pavlů, Věra ; Křížek, Tomáš (advisor) ; Kozlík, Petr (referee)
This thesis deals with the development and optimization of a method for the determination of tryptophan and its metabolites - serotonin and melatonin - in plant material, in grapevine, during one analysis. It uses a high-pressure liquid chromatography. The theoretical part is about tryptophan, its metabolism and basic properties of its metabolites - serotonin and melatonin. Their occurrence in wine is also discussed. Analytical techniques by which these analytes can be determined are also provided. Then information about modern stationary phases, that are suitable for this species, is included. The experimental part consists of optimization of the method, measurement of calibration dependences and measurement of real samples. It is measured by the method of reverse phase chromatography. As first stationary phase it is used a C18 column with core-shell packing, second is a BEH Phenyl column. The mixture of 10 mM acetate buffer (pH = 4.5) and methanol is used as the mobile phase. For detection UV at wavelength 254 nm is used, then for greater sensitivity mass detectionis is used. The basic conditions for the experiment have been set. At the beginning of the analysis, the mobile phase contains 95 % (v/v) buffer and 5 % (v/v) methanol. Then the methanol content is linearly increased to 80 % (v/v) from...
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Expression of enzymes of kynurenine and methoxyindole pathway in the rat pineal gland, liver and heart in circadian profile and after lipopolysacharide administration
Hrubcová, Leona ; Bendová, Zdeňka (advisor) ; Svobodová, Irena (referee)
Tryptophanis anaminoacidwhichhasmanyfunctionsinthebody. Besidesitsparticipationin theproductionofproteins,itactsasasubstrateforthekynurenineandmethoxyindolemetabolic pathways. The kynurenine pathway ends with the production of nikotinamid e adenin dinukleotide ( NAD + ) ,whichisneededfortheproductionofcellularenergy. Thus,withincreased energy demand during immune system activation, the activity of the kynurenine pathway is increased. Dueto increasedactivity,itproduces more immunoactiveandneuroactivemetab olites suchaskynurenicacidandquinolinicacid.Thesemetabolitesareinvolvedinmanyprocessesin the body and affect the pathology of many diseases. Studies show that regulation of these metabolites could be a key innovation in the treatment of cance r, cardiovascular or neurodegenerative diseases. The methoxyindole pathway is another important tryptophan processingpathway.Itsbest - knownmetabolitesareserotonin,whichactsasaneurotransmitter, andmelatonin,ahormonewithimmunomodulatoryeffect sregulatedby thecircadianclock . This workdeals with thecircadian rhythmicityofenzymeexpressionofthesetwo metabolic pathways.Italsodescribestheeffectofsystemicadministrationoflipopolysaccharideendotoxin ontheexpressionofgenesoft heseenzymes.OurexperimentsusedWistarratsat30daysofage. The lipopolysaccharide was administered...
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Molecular mechanisms of mammalian circadian clocks, its sensitivity to constant light and aging
Novosadová, Zuzana ; Sumová, Alena (advisor) ; Doležel, David (referee) ; Mráz, Miloš (referee)
Many processes in mammalian body exhibit circadian rhythms. These rhythms are driven by an intricate system composed of the central pacemaker, suprachiasmatic nuclei (SCN) in the brain, which entrains the peripheral oscillators in various organs, such as pancreas, liver, colon and lungs. Circadian clocks are autonomously driven in each cell based on molecular circuits involving so called clock genes, such as BMAL, CLOCK, PER and CRY. Age- dependent impairment of physiological functions of mammalian body, such as behaviour and metabolic functions, has been well documented. However, it has not been fully elucidated whether the impairment is linked with worsening of the circadian clock function. The aim of our study was to find out whether i) aging affects basic properties of the circadian clock in SCN and peripheral organs, such as pancreas, colon, liver and lungs, ii) aging- induced changes in glucose homeostasis affect the properties of the circadian clock in the pancreas, and iii) the sensitivity of circadian clock in SCN and peripheral organs to disturbances in environmental lightning conditions is altered during aging. We used groups of adult (9 months) and aged (25 months) animals which were subjected to 3 different light regimes, namely to light/dark regime (LD 12:12), constant light (LL) and...
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The effect of melatonin on rhythmic ATP release from organotypic cultures of the rat SCN
Dvořáková, Barbora ; Svobodová, Irena (advisor) ; Jelínková, Dana (referee)
The rhythm of ATP accumulation is an one of examples of circadian rhythmicity which is demonstrated across the animal kingdom. It is located in the suprachiasmatic nucleus of hypothalamus, which is a centre of circadian clock and imposes rhytmicity on a whole organism. The question concering the ATP rhythm in an organotypic culture and the impact of melatonin on it has been discussing in this thesis. The synthesis of melatonin is regulated by the activity of the SCN and the hormon itself is known for its feedback on the SCN and a capability of regulating it. It has been shown that ATP rhythm is significantly inhibited under the constant control of melatonin and this inhibition is dose-dependent on a scale of 0,1-10 nM. In case of one-time applied melatonin in 4 p.m. there is no reduction in the accumulation of extracellular ATP but there is a phase shift in ATP rhythm. It has also been shown that ATP rhythm is inhibited and desynchronized under the control of tetrodotoxin which blocks an electric activity of neurons. These results show that melatonin is capable of inducing phase delay of ATP rhythm in SCN and reducing an amount of extracellular ATP, that the effect of melatonin is probably mediated by specific receptors and lastly that ATP rhythm is a result of cell-cell interaction between neurons...
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