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The photoperiodism and hibernation
Pařezová, Lucie ; Bendová, Zdeňka (advisor) ; Weissová, Kamila (referee)
Many organisms living in seasonal environments use annual changes in the length of the day for timing of their responses, such as reproduction, migration or hibernation. Hibernation allows animals to survive difficult periods associated particularly with cold temperatures and lack of food resources. This adaptation requires many physiological, morphological and behavioral changes. Some of these changes take longer, so their right timing is crucial. For most hibernators in temperate regions shortening of the photoperiod is the most reliable signal for initiation of these changes. This work describes the transduction of photoperiodic information to the melatonin signal, its effects in the pars tuberalis and the significance of this structure in seasonal physiology. A more detailed description is devoted to hibernation, and in the last chapter there is briefly mentioned photoperiodism in nonhibernating organisms. Powered by TCPDF (www.tcpdf.org)
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Circadian system in patients with Alzheimer's disease
Weissová, Kamila ; Sumová, Alena (advisor) ; Stuchlík, Aleš (referee)
Alzheimer's disease (AD) is a severe neurodegenerative disease that primarily affects the elderly population. Recently, epidemiological studies have pointed to significant increase in the disease cases within the world population, and therefore, it is important to pay more attention to it. The most distinctive symptom of AD is an impairment of memory, especially its episodic component. Apart from this, sleep-wake rhythm disturbance is also very burdensome symptom of this disease. An increasing sleep fragmentation during the night and an increasing number of naps during the day in AD patients represents one of the biggest complications for home caregivers. Therefore, sleep problems are one of the most common reasons for a permanent hospitalization of patients with AD. Apart from these difficulties for the patient's surroundings, the irregular and altered sleep-wake rhythm has also many negative physiological impacts on the patient's health. The alternation in sleep and waking follows a prominent daily rhythm. The sleep-wake rhythm is driven by a circadian system and, therefore, the episodes of sleep and waking regularly alternate with approximately 24h period even in a non-periodic environment. Master circadian clock is located in the suprachiasmatic nucleus of hypothalamus (SCN). SCN is an...
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Association of selected polymorphisms with clock genes with a extreme chronotypes
Turečková, Lucie ; Bendová, Zdeňka (advisor) ; Weissová, Kamila (referee)
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...
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Cerebral organoids as a neurodevelopmental model of schizophrenia
Sovíčková, Lucie ; Weissová, Kamila (advisor) ; Olejníková, Lucie (referee)
The neurodevelopmental model of schizophrenia incorporates genetic and environmental factors, which both play a role in the development of this disorder. For example the risk of developing schizophrenia is increased by prenatal stress in a sex-dependant manner. Fibroblast growth factor receptor 1 plays a role in neurodevelopmental abnormalities and has been found to influence cortical development, development of dopaminergic neurons and genes dysregulated in schizophrenia. Circadian, hypothalamic-pituitary-adrenal axis and sleep abnormalities are also common in schizophrenia patients and they might increase susceptibility to psychosis via dopaminergic system. The schizophrenia susceptibility gene Disc1 has been found to play a role in sleep abnormalities and regulation of radial glia cell cycle. Cerebral organoids, which are generated by using human induced pluripotent stem cells, model human brain development and could be used for further studies of neurodevelopmental model of schizophrenia. Cerebral organoids could be improved in the future by vascularization and bioengineering methods. Key words: cerebral organoids, schizophrenia, circadian rhythms, stress, FGFR1, DISC1, glucocorticoids
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Circadian system in peripheral clock in neurodegenerative disorder and affective disorder and their synchronization in constant light condition
Weissová, Kamila ; Kopřivová, Jana (advisor) ; Kemlink, David (referee) ; Svoboda, Jan (referee)
Summary: The circadian system plays an important role in human physiology and pathophysiology. It controls all processes that repeat in our body within a 24-hour period. It is a complex system that works from the behavioral level to the molecular level. This system is controlled from the central brain structure located in the hypothalamus, but its rhythmic manifestations can also be observed in almost any individual body cells. Disruption of this system in humans is often associated with the development of affective disorders or neurodegenerative diseases. The affective disorder has often been associated with a phase shift in some of the circadian driven outputs, as for example, rhythm in their physical activity. The patients with neurodegenerative disorders are seen to have circadian amplitude damping in a series of circadian rhythms. Therapeutic approaches which aim to stabilize and strengthen the circadian rhythms have also a positive long term effect on the course of these diseases. Interestingly, in the genetic studies of these diseases, a couple of specific polymorphisms have been identified in areas related to the molecular mechanism of the internal clock. In this thesis, I tried to look at the human circadian rhythms from several different angles. In the first part of this thesis I tried to identify...
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Circadian sleep regulation and sleep deprivation
Zeithamlová, Barbora ; Weissová, Kamila (advisor) ; Honzlová, Petra (referee)
The circadian system is designed to generate circadian rhythms and serve as the human inner clock. This is achieved through the molecular mechanism of autonomous transcriptional-translational feedback loops, in which so-called clock genes are involved. Circadian rhythms regulate the timing of physiological and behavioral processes, including sleep. Sleep is important for the proper functioning of the human organism. As a result of desynchronization of circadian rhythm, disturbances of sleep arise which threaten the mental and physical state of man. One of the examples is sleep deprivation which is deffined as a lack of necessary amount of sleep. Besides its negative effect on human health, there had been also reported positive effect in the treatment of symptoms in patients with unipolar depression. Other studies suggest that deprivation causes a reset of the circadian system, correcting the abnormal functioning of the internal clock. These effects have only a short duration, but it appears that they could be stabilized by combining sleep deprivation therapy with other therapeutic approaches. However, it is crucial to understand the exact mechanism that causes the positive effect in sleep deprivation therapy.
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Dysfunctions of interneurons in schizophrenia
Hrůzová, Karolína ; Stuchlík, Aleš (advisor) ; Weissová, Kamila (referee)
Schizophrenia is a serious neuropsychiatric disorder characterised by abnormal behaviours, perception and thoughts. It is a neurodevelopmental disease of two types of factors - genetic predispositions and environmental factors. The exact cause of schizophrenia remains, however, elusive. Interneurons are types of neurons, mostly exerting inhibitory action and their dysfunctions are associated with pathogenesis of schizophrenia. They are essential in the generation of neuronal oscillations, which play an important role in cognitive functions. Disruption of these oscillations (especially gamma band) could be paralleled by negative, positive or cognitive symptoms of schizophrenia. These interactions could be possible discerned with an innovative technique called optogenetics. Optogenetics is a combination of genetic and optical approaches to controlling activity of specific targeted neurons. With this method we can study animal models of schizophrenia with great insight, which could give us an explanation of abnormalities in behaviour caused by neuronal disruption. Keywords: schizophrenia; interneurons; animal models; neuronal oscillations; optogenetics
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The photoperiodism and hibernation
Pařezová, Lucie ; Bendová, Zdeňka (advisor) ; Weissová, Kamila (referee)
Many organisms living in seasonal environments use annual changes in the length of the day for timing of their responses, such as reproduction, migration or hibernation. Hibernation allows animals to survive difficult periods associated particularly with cold temperatures and lack of food resources. This adaptation requires many physiological, morphological and behavioral changes. Some of these changes take longer, so their right timing is crucial. For most hibernators in temperate regions shortening of the photoperiod is the most reliable signal for initiation of these changes. This work describes the transduction of photoperiodic information to the melatonin signal, its effects in the pars tuberalis and the significance of this structure in seasonal physiology. A more detailed description is devoted to hibernation, and in the last chapter there is briefly mentioned photoperiodism in nonhibernating organisms. Powered by TCPDF (www.tcpdf.org)
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Circadian system in patients with Alzheimer's disease
Weissová, Kamila ; Sumová, Alena (advisor) ; Stuchlík, Aleš (referee)
Alzheimer's disease (AD) is a severe neurodegenerative disease that primarily affects the elderly population. Recently, epidemiological studies have pointed to significant increase in the disease cases within the world population, and therefore, it is important to pay more attention to it. The most distinctive symptom of AD is an impairment of memory, especially its episodic component. Apart from this, sleep-wake rhythm disturbance is also very burdensome symptom of this disease. An increasing sleep fragmentation during the night and an increasing number of naps during the day in AD patients represents one of the biggest complications for home caregivers. Therefore, sleep problems are one of the most common reasons for a permanent hospitalization of patients with AD. Apart from these difficulties for the patient's surroundings, the irregular and altered sleep-wake rhythm has also many negative physiological impacts on the patient's health. The alternation in sleep and waking follows a prominent daily rhythm. The sleep-wake rhythm is driven by a circadian system and, therefore, the episodes of sleep and waking regularly alternate with approximately 24h period even in a non-periodic environment. Master circadian clock is located in the suprachiasmatic nucleus of hypothalamus (SCN). SCN is an...
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