Long-term exposure to constant light results in desynchronization of the circadian system in an adult and is associated with reduced efficiency of many physiological functions timed to the exact time of day, or with the development of some of the so-called civilization diseases. Constant light in adults also results in deterioration of the cognitive abilities or changes in the sleep structure. The effect of night light on the health of an adult organism is studied mainly in connection with shift work or with light pollution. The question of what effect the increased level of night light has on the development of the organism, especially on the development of the nervous system and the circadian system itself, is less studied. This diploma thesis focused on the identification of the extent of changes in the expression of Per2, Nr1d1, Stat3, BDNF genes, as well as genes encoding NMDA receptor subunits and some tissue-specific genes in the retina. Our experiments were performed on adult Long-Evans rats, that spent the first 20 days of their postnatal development in low-intensity constant light. Changes in expression were determined by quantification of mRNA by RT-qPCR in the structures of the frontal and parietal cortex, olfactory bulb, hippocampus, suprachiasmatic nucleus and retina. Behavioral tests...

Circadian rhythm of parathyroid hormone (PTH) is well documented, but its physiological role is not fully understood. In healthy individuals, biochemical markers of bone remodeling follow a similar circadian rhythm to PTH with a nocturnal rise in bone resorption and formation. The loss of PTH diurnal variation was observed not only in primary hyperparathyroidism, but also in patients with postmenopausal osteoporosis. Continuously elevated concentrations of PTH lead to excessive stimulation of bone resorption, whereas intermittent PTH administration has a strong osteoanabolic effect in patients with osteoporosis. It has not been examined whether the skeletal sensitivity to PTH action depends also on the time of its application. The aim of our study was to verify the hypothesis that the application of teriparatide (TPTD, recombinant human PTH [1-34]) at different times of the day in the context of its diurnal variability affects the physiological circadian rhythm of bone remodeling and also the bone mineral density (BMD) after the long-term TPTD treatment. Fourteen women with postmenopausal osteoporosis treated with 20 micrograms of TPTD daily, applied subcutaneously either in the morning or evening, were included in the first study. The concentration of serum C-terminal telopeptide of type I collagen...

In order to adapt to changing external conditions, organisms developed the endogenous biological clock for predicting daily alterations. This so-called circadian system drives functions and processes in the whole body with an approximately 24h period. The central oscillator, located in hypothalamic suprachiasmatic nuclei (SCN), is synchronized by light and subsequently sends the information about the time of the day to the rest of the body. Even in the ontogenesis, the functional SCN clock is crucial for proper development as well as health later in life. Since the maturation of embryonic SCN is not completed before birth, maternal signals seem to play a fundamental role in setting and synchronizing the fetal clock. During my PhD studies, we focused on elucidating the nature of maternal signals and their diverse impact on fetal SCN of rat and mouse models. We have revealed that developing SCN is able to sense distinct signals related to various maternal behavioral regimes. Importantly, we have discovered eminent role of glucocorticoids in synchronizing the fetal SCN, along with their ability to accelerate SCN development. These observations point out the importance of regular daily routine and noxious effect of stress during pregnancy. Since the mother communicates with the fetus through placenta...

The circadian system has evolved in organisms as an adaptation to periodic changes in the environment. Its task is to ensure regular entrainment between the solar cycle and the internal period of the organism, and to generate signals that synchronize behavioral and physiological processes in the body with the solar cycle. The whole mechanism takes place at the cell level, where there are regular oscillations of the transcriptional translation loops of the clock genes occur within 24 hours, thus ensuring a regular rhythm of the organism. However, the circadian system may not generate the same length of period in humans and may differ in the degree of entrainment with the external cycle. Base on that there are developed so-called individual time preferences. These different preferences are referred to as chronotypes, which fall into five categories: extremely evening, moderate evening, intermediate, moderate morning, and extremely morning type. Clock gene polymorphisms are considered to be one of the possible causes of these differences. The association of selected clock gene polymorphisms with extreme chronotypes is the subject of this diploma thesis. We obtained a saliva sample for DNA isolation from volunteers with extreme chronotypes. Using molecular methods of PCR, restriction digest and...

The circadian system controls the timing of most of the physiological functions and behaviour within approximately 24 hours period. The light/dark cycle aligns this circadian period with the exact length of the solar day. Light information is conveyed via ipRGC cells in the retina, with maximum sensitivity in the blue part light (460-480nm wavelength). The information proceeds to the main circadian clocks located in the suprachiasmatic nuclei. This clock regulates the synthesis of neurohormone melatonin in the pineal gland whose high night level can be rapidly downregulated by the light at night. The major aim of this study was to test the effectiveness of the blue or green light-emitting device, potentially utilized in clinical practice, to suppress the night melatonin level and provide thus the first evidence that this device may affect the circadian system. The results show that the light emitted by this device has the potential to lower melatonin levels in most subjects with the higher efficiency in the blue range. Key words: circadian rhythms, melatonin, light pulse, eyelids, blue and green light

The aim of this diploma thesis is to deal with the issue of both mental and social health in relation to the circadian rhythm. This work was created at the same time as a project GAJU no. 101/2011/S. "The Psychosocial and Somatic Indicators in Comparison to the Circadian Rhythm". In the theoretic part of this work the issue of the mental and social health is solved as well as the definition and characterization of the pubescent period is given here. The matter of the circadian and diurnal rhythms is explicated here as well. In the experimental part there is a questionnaire research involving 250 pubescents (125 girls, 125 boys). The age of the pubescents ranged from 11 up to 13 years. The average age for both of the sexes was 13 years. The data capture was proceeding from May 2011 till February 2012. For this purpose the method of two standardized questionnaires was used. The questions from the social sphere originated from the questionnaire called The Quality of Life, Cummins (1997) ComQol S5. The questions solving the issue of the circadian rhythms were chosen from the questionnaire called The Circadian Typology CIT, Harada, Krejčí (2012). The gained data were evaluated by the means of the basic statistic methods and reciprocal correlation. On the basis of results I concluded that some data are correlated with social and mental health, strongly affecting the concept and the importance of sleeping. At the beginning of this work 5 hypothesis were provided. Three of them were confirmed by data analyze.

This thesis deals with quality of life with regard to circadian and diurnal rhytm of children at children´s homes in South Bohemia. The theoretical part deals with pubescent and adolescent age of a child, circadian and diurnal rhytm, sleep and life quality of children. I also describe issues of value orientation, family and upbringing at children´s institutions. The most important part of the thesis was questionnaire development. QuestionnaireThe Circadian Typology CIT Harada, Krejčí (2010). There is a group of pubescents (10-14 years) and a group of adolescents (15-19 years). My research involves children´s homes in Písek, Volyně, Radenín, Žíchovec, Koryto, Boršov nad Vltavou, Homole and in Zvíkovské Podhradí. Data collecting took place since February 2012, to October 2012. The conclusion of the thesis shows results of completed questionnaires from 118.

This thesis deals with monitoring changes of body weight of adolescent girls at the age of 16 20 years old through one calendar year in the context of a season of the year and chronotypology of a personality. According to this typology the monitored people are divided into so called "larks", who are more active early in the morning and during the day and "owls" whose activity rises in the evening and at night. The theoretical part deals with circadian rhythms, their function, role in the life of an individual and also their disorders. It focuses on a developmental specification of adolescent girls, lifestyle in this period of life, changes of body weight and diet. Another part is the meaning of the sleep, its need and associated with good sleep habits and sleep hygiene. In the practical part there is described a methodology along with the results of the research and employment of this project in practice.

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...

The main objective of the diploma thesis was to create a project of a tutorial on the subject of animal and human biorhythms. The tutorial is intentioned as an additional biology curriculum at grammar schools. Analysis of teaching biorhythms in secondary Biology schoolbooks used in the Czech Republic preceded a composition of this tutorial. Processing literary research based on reading Czech and foreign-language literature was another theoretical resource. The tutorial is divided into three parts {--} {\clqq}Animal Biorhythms``, {\clqq}Human Biorhythms`` and {\clqq}Seasonal Animal Biorhythms``. Some parts of the tutorial were verified in practice.