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Developmental changes in expression levels of the chosen subunits of NMDA and AMPA receptors and action of their antagonists on physiological and epileptic phenomena
Szczurowska, Ewa Katarzyna ; Mareš, Pavel (advisor) ; Rokyta, Richard (referee) ; Bendová, Zdeňka (referee)
During early stages of postnatal development, glutamate receptors of NMDA and AMPA type, undergo intensive functional changes due to modifications of their subunit composition (Pachernegg et al., 2012: Paoletti et al., 2013). The NR2B-containing NMDARs (NR2B/NMDARs) and GluA2-lacking AMPARs (Ca 2+ -permeable) that are highly expressed in immature brain, are implicated in increased excitability, seizures generation, excitotoxicity, and neuronal death (Vizi et al., 2013). Pharmacological blockade of these types of receptors by their specific antagonists, can exhibit anticonvulsant effects at early stages of postnatal development. Therefore, we tested the influence of the IEM1460, a specific antagonist of Ca 2+ -permeable AMPARs and the Ro 25-6981 maleate, a highly selective and activity-dependent antagonist of NR2B/NMDARs on physiological excitability and epileptic phenomena induced in immature rats. Anticonvulsant action of IEM1460 was tested in two models of epileptic seizures: pentylenetetrazol (PTZ)- induced convulsions and cortical afterdischarges (ADs), induced in animals at P12, P18 and P25. Our results indicate that the effects of IEM1460 on various types of seizures depend on their sites of origin in the brain, developmental stage, and GluA2 subunit expression profile. To clarify the action...
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Utilization of biocompatible hydrogels based on 2-hydroxyethylmethacrylate to bridge the spinal cord lesion
Lesný, Petr ; Syková, Eva (advisor) ; Rokyta, Richard (referee) ; Hampl, Aleš (referee)
Utilization of biocompatible hydrogels based on 2-hydroxyethylmethacrylate to bridge the spinal cord lesion MUDr. Petr Lesný Biocompatible hydrogels based on copolymers of 2-hydroxyethylmethacrylate are suitable for implantation into a central nervous tissue lesion. Our prepared hydrogels were macroporous with predominantly communicating pores, and their mechanical properties were similar to those of spinal cord tissue. After we confirmed their biocompatibility by the growth of mesenchymal stem cells and determined the hydrogel diffusion properties, we implanted the prepared hydrogels into acute spinal cord injury in laboratory rats and studied the process of spinal cord tissue regeneration within the implants. When the hydrogels were implanted in subacute phase of spinal cord injury, we observed favorable impact on the spinal cord tissue regeneration and reduction of pseudocyst formation. Using histological and immunohistochemical methods, we observed the ingrowth of central nervous tissue elements (connective tissue, vessels, neurofilaments, Schwann cells, astrocyte processes) into the hydrogels implanted into the spinal cord hemisections. We have found that copolymerization with a positively charged ammonium salt increases the adhesion of the cells to the hydrogels in vitro and the ingrowth of...
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Obstetric brachial plexus palsy
Mencl, Libor ; Haninec, Pavel (advisor) ; Rokyta, Richard (referee) ; Ehler, Edvard (referee)
Obstetrical brachial plexus palsy (OBPP) displays a stable incidence of 0.15 - 3 per 1,000 live births. Most children show good spontaneous recovery, but a recent literature reviews show that a residual deficit remains in 20% to 30% of children. Shoulder dystocia, macrosomia and instrument delivery, forceps or vacuum extraction present the greatest risk for brachial plexus injury. Caesarean section, having a twin or multiple birth mates seems to offer some protection against injury. The resulting nerve injury may vary from neurapraxia or axonotmesis to neurotmesis and root avulsion from spinal cord. In neurapraxia or axonotmetic lesions complete recovery will usually occur over the course of weeks or months. In a neurotmetic injury or in case of root avulsion, the most sever type of lesion, useful regeneration of axons cannot take place. Although we perform electromyography and imaging studies, the final decision of operation relies heavily on the clinical examination. Manual muscle testing system although reliable for examination of motor power in adults is not suited for use with infants. All patients involved in the study were evaluated using the Active Movement Scale (AMS), which greatly increases the ability to detect partial movements. The results of neurophysiological investigations in older...
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Changes of the eExtracellular space diffusion parameters during acute pathological states in the rodent brain and the role of AQP4 channels in cell swelling
Dmytrenko, Lesia ; Vargová, Lýdia (advisor) ; Druga, Rastislav (referee) ; Rokyta, Richard (referee)
1. SUMMARY The diffusion properties of the extracellular space (ECS), which govern the movement of neuroactive substances through its volume and thus extrasynaptic transmission, are profoundly affected in states associated with cell swelling. In this work we compared ECS diffusion parameter changes during acute cell swelling in vivo in models of pilocarpine-induced status epilepticus (SE) and ischemia/anoxia evoked by cardiac arrest. To elucidate mechanisms involving the aquaporin 4 (AQP4) water channel in pathological cell swelling, we used models of hypotonic stress and elevated K+ in coronal slices of genetically modified mice. The ECS diffusion parameters volume fraction ( = ECS volume/total tissue volume), tortuosity factor (2 = apparent diffusion coefficient/free diffusion coefficient) and non-specific uptake (k') were determined by the real-time iontophoretic method, which was the primary method used in my thesis work. Changes in the activity-related extracellular K+ concentration ([K+ ]e) were measured using ion-selective microelectrodes. The apparent diffusion coefficient of water (ADCW) was determined by diffusion-weighted MRI. In both models in vivo, ECS volume fraction and ADCW decreased; these changes were more profound and their time course was faster during terminal ischemia/anoxia in...
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Learning and memory in Nogo-A knockdown rats
Petrásek, Tomáš ; Stuchlík, Aleš (advisor) ; Zach, Petr (referee) ; Rokyta, Richard (referee)
The Nogo-A protein belongs among the most important regulatory molecules in the brain, regulating development of neuronal and glial cells, axon guidance and adult synaptic plasticity. Although it has been studied mainly as an obstacle to axon regeneration after CNS injury, it plays a role in many pathological conditions, including neurodegenerative and neuropsychiatric diseases. This work offers a literature review of the current knowledge about functions of Nogo-A and related proteins, and then recapitulates the results of experiments focused on the impact on decreased expression of Nogo-A on behavior in a transgenic rat model. The most important finding is that the Carousel Maze performance, tapping higher cognitive functions such as cognitive coordination and cognitive flexibility, is remarkably impaired in this model, while other cognitive functions, such as spatial navigation and both spatial and non-spatial memory are spared in the Nogo-A deficient rats. The results are discussed in the context of a hypothesis linking Nogo-A mutations or abnormal expression to human schizophrenia. We conclude that the Nogo-A deficient rats constitute a very promising animal model of schizophrenia and deserve further attention. Powered by TCPDF (www.tcpdf.org)
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Age related changes in the central auditory system in the laboratory rat
Burianová, Jana ; Popelář, Jiří (advisor) ; Stuchlík, Aleš (referee) ; Rokyta, Richard (referee)
Age-related hearing loss, presbyacusis, is becoming one of the most common health disabilities in elderly people. Despite intensive research, age-related changes are still poorly understood and, given the continuous aging of the population, it is desirable to improve our knowledge of the mechanisms of presbyacusis. Consequently we decided to study age-related changes that appear in the structure and function of the central auditory system in the brain of experimental animals. In the first experiment we tested the hypothesis that during aging there is substantial decline of GABA-mediated inhibition in the central auditory system of the rat. We evaluated levels of both isoforms of glutamatedecarboxylase (GAD65, GAD67), a key enzyme in GABA synthesis. Western blot analysis revealed an overall decrease in levels of both isoforms in the inferior colliculus as well as the auditory cortex in aged rats. The same pattern was found when we used immunohistochemistry analysis; there was a decrease in the number of GAD65 and GAD67-ir neuronal bodies and a decrease in the density of the labeling. The results were similar for both GAD isoforms and both studied strains - the normally aging Long Evans strain (LE) and the Fischer 344 (F344) strain known for accelerated aging. In the next experiment we evaluated...
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Muscarinic acetylcholine transmission and Alzheimer's disease
Janíčková, Helena ; Doležal, Vladimír (advisor) ; Blahoš, Jaroslav (referee) ; Rokyta, Richard (referee)
Impairment of the cholinergic neurotransmission system is regularly detected in animal models of Alzheimer's disease as well as in human patients suffering from this serious disease. Moreover, there is increasing amount of evidence suggesting that activation of individual mAChR subtypes specifically influences the cleavage of APP, the precursor for β-amyloid. APP can be processed in an amyloidogenic or non-amyloidogenic pathway and a relative abundance of these patways contributes to establishing the final concentration of neurotoxic β-amyloid in the brain. In this work, I have studied the acute and chronic effects of A β1-42 on binding and functional characteristics of mAChR. I have demonstrated that Aβ1-42 present in cell culture expressing the individual subtypes of mAChR negatively and specifically influences the function of the M1 mAChR subtype. I have also detected a decline in muscarinic receptor-mediated signal transduction in brain tissue of young adult APPswe/PS1dE9 mice, a commonly used animal model of Alzheimer's disease. Demonstration of the impairment of muscarinic transmissin in transgenic mice by soluble β-amyloid that occurs earlier than amyloid pathology and behavioral deficit, and its imitation by soluble Aβ1-42 in vitro lend strong support to the notion of the early involvement...
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Astrocytic changes in a mouse model of Alzheimer's disease
Kulijewicz-Nawrot, Magdalena ; Syková, Eva (advisor) ; Rokyta, Richard (referee) ; Zach, Petr (referee)
1. SUMMARY: In this thesis we reported astrocytic atrophy characterized by a reduction in the surface area and volume of GFAP-positive glial cells in the prefrontal cortex of 3xTg-AD mice - an important morphological alteration starting far before any well known histopathological hallmark of AD. This change is present in parallel with homeostatic failure suggested by the decreased expression of GS. Those alterations can have drastic effects on brain connectivity and the biochemistry of the main neurotransmitters within the brain, such as glutamate and GABA. GFAP is implicated in a variety of processes, such as cell migration and proliferation, neurite outgrowth, astrocytic glutamate transporter expression (GLAST and GLT-1) and synaptic plasticity, so that every change can shift the astrocytes' role from physiology to pathology. In the case of affected GFAP-IR astrocytes, the withdrawal of processes from neurons and synapses can lead to a severe transmission crush, due to the uncontrolled spillover of the neurotransmitter from the synaptic cleft, inadequate metabolic support and the lack of a physiological barrier between the affected synapse and other synapses in its close vicinity. This will directly disturb the reciprocal connections between the affected brain regions, inluding the important structures...
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The coronary atherosclerosis regression during hypolipidemic therapy
Kovárník, Tomáš ; Aschermann, Michael (advisor) ; Rokyta, Richard (referee) ; Pudil, Radek (referee)
Background: There is no study focusing on changes of coronary atherosclerosis during dual hypolipidemic therapy with statin and ezetimibe. Methods: 107 patients with stable angina were enrolled and the final analysis was performed in 89 patients. Randomization was 1:1 to the group A (atorvastatin 80mg and ezetimibe 10mg) and to the standard group S. Treatment period was 12 months. Results: Changes of percent atheroma volume (PAV) were -0,4% in group A and + 1,4% in group S, p=0,014. Combine atherosclerosis regression (increase of lumen volume together with decrease of PAV) was found more frequent in group A (40,5%) than the group S (14,9%), p=0,007. The target LDLc level < 2mmol/l, presence of at least four of five atherosclerotic risk factors, and decrease of VCAM level were independent predictors for plaque regression. There were no significant differences in plaque composition between the two groups over the duration of the study. However during analysis the two groups together, fibrous and fibro-fatty tissues decreased and dense calcification and necrotic core increased during follow-up. Conclusion: The dual hypolipidemic therapy starts atherosclerosis regression. Despite significant decrease of lipid levels the continuous plaque shift from fibro and fibro-fatty to necrotic with calcification...
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Neuromodulation in treatment of selected dystonic syndromes
Havránková, Petra ; Jech, Robert (advisor) ; Štětkářová, Ivana (referee) ; Rokyta, Richard (referee)
Dystonia is a neurological syndrome characterized by the involuntary contraction of opposing muscles, causing twisting movements or abnormal postures (modified by Fahn, 1987). Writer's cramp is the most common form of task-specific focal dystonia. In the first study, patients with writer's cramp were evaluated for differences in cortical activation during movements likely to induce cramps (complex movements) and movements which rarely lead to dystonia (simple movements). Although complex patient movements during fMRI were never associated with dystonic cramps, they exhibited abnormally decreased cortical activity. This was not observed in simple movements and was unrelated to the character of handwriting or the presence/absence of visual feedback. Our results support the theory of dualistic sensorimotor system behavior in writer's cramp. As the somatosensory system is believed to be affected in focal dystonia, we focused on modulation of the primary somatosensory cortex (SI) induced by repetitive transcranial magnetic stimulation (rTMS) in the second study, in order to improve writer's cramp. In conclusion, 1 Hz rTMS of the SI cortex can improve manifestations of writer's cramp while increasing cortical activity in both hemispheres. Handwriting as well as subjective assessment improved in most...
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