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Organization of the auditory cortex and changes in the auditory system in presbycusis.
Profant, Oliver ; Syka, Josef (advisor) ; Vymazal, Josef (referee) ; Chrobok, Viktor (referee)
2. Abstract The aim of my study was to identify specific features of the structure and function of neurons in the auditory cortex of rat and to analyze age-related changes in the inhibitory system (GAD 65 and 67) in the central auditory structures of the same species. Based on the findings in the animal model we focused on changes in the central part of the auditory pathway and auditory cortex in aging human population that were examined by various MRI techniques (spectroscopy, morphometry, diffusion tensor imaging and functional MRI). We found that the most significant feature of neurons in the auditory cortex is the presence of the hyperpolarization-activated cation current that influences functional properties of neurons. The differences among neurons in different fields of the AC were based on their specific functional characteristics, with the tonotopy being the key factor of the AC structural organization. Aging of the auditory system has a negative influence on the speech understanding in which the processing of temporal parameters of the sound plays a significant role. In animal experiments we observed decreases of the enzymes GAD65 and 67 (that catalyze synthesis of the main inhibitory neurotransmitter GABA) in central parts of the auditory system. Inhibition is the key factor in coding and...
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The comparison of two waste water treatment systems - constructed wetlands and mechanical.
Dudíková, Kristýna ; Benešová, Libuše (advisor) ; Vymazal, Jan (referee)
This thesis is focused to the comparison of two wastewater treatment systems - constructed wetlands and mechanical-biological wastewater treatment plant. The main goal of the theses is to compare two types of wastewater treatment systems and to evaluate hypothesis that constructed wetlands are cheaper and more efficient than mechanical-biological wastewater treatment plant. To be able to compare two various wastewater treatment systems 18 (9 constructed wetlands and 9 mechanical-biological plants, three size groups of both types of plants) wastewater treatment plant were chosen and compared. The treatment effectiveness, investment and operating costs, advantages and disadvantages of both the systems were compared. The information about all individual systems was obtained from the local municipalities, operators and partially from the Ministry of Environment of CR. Obtained data involved treatment technology, amount of annual treated water, building data and capital and operating costs. In some waste water treatment plant (WWTP) the water samples were taken and the analyses of chosen parameters (not measured in WWTP) were done. Once in 2010 year the samples of water, sediments and sludges were taken and the analyses of heavy metals was done. For assessment of operational problems in constructed...
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Influence of corticosteroids and movement disorder on development of osteoporosis in patients with multiple sclerosis (MS)
Týblová, Michaela ; Kubala Havrdová, Eva (advisor) ; Vymazal, Josef (referee) ; Taláb, Radomír (referee)
Introduction: Multiple sclerosis (MS) is associated with impaired bone health in comparison to an equally healthy population, even already in patients at the onset of this disease. The main risk factors for development of osteoporosis in MS patients are known. The aim of the study was to find the relationship of the decrease in bone mineral density (BMD) to the administered cumulative dose of steroids and to other risk factors in MS, mainly to the degree of motor deficit. Further goal was to evaluate the occurence of the risk of low-trauma fractures in multiple sclerosis patients.. The BMD and muscle mass was compared in MS patients (women and men) and control subjects, to examine the effect of main ones - physical disability and long-term glucocorticoid (GC) therapy on BMD. Clinical values of bone remodeling markers were evaluated in assessment of rate of bone loss in patients with multiple sclerosis long term treated with low dose of GC. Patients and methods: We used dual -energy X-ray absorptiometry for a measurement of BMD in 591 MS patients (455 females and 136 males) in 2004 and in cross-sectional longitudinal study published in 2014 with 474 patients (353 women and 121 men). Out of the whole study group body composition was evaluated in 250 MS females, 104 males and 247 healthy controls (193...
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The role of accumulation of iron and other metals in the pathophysiology of neurodegenerative diseases
Mašková, Jana ; Dušek, Petr (advisor) ; Vymazal, Josef (referee) ; Bártová, Petra (referee)
The role of metal accumulation in the pathophysiology of neurodegenerative diseases has been a hot topic in recent years due to the possibility of its treatment by chelating agents. Although the mechanisms of neurodegeneration are well known, the role of metal accumulation is still unclear. The main limitation are unsatisfactory methods for in vivo metal imaging; the most widely used technique is magnetic resonance imaging (MRI). Our aim was to assess the possibility of using transcranial sonography (TCS) in differential diagnosis of neurodegenerative diseases and to further explore the underlying factors of echogenicity. In the first study, using TCS fusion with MRI, we focused on location verification of the commonly assessed structures (substantia nigra and nucleus lentiformis) and exclusion of possible focal structural changes affecting the echogenicity in WD and PD patients. Moreover, obtained MRI were used for semi-quantitative comparison with TCS images. Although TCS has been confirmed to be highly beneficial in differential diagnosis of Wilson's disease and it should be recommended as a screening method for extrapyramidal patients with atypical course of the disease, the direct relationship between TCS and metal deposits could not be proven. The obtained results from the ultrasound fusion...
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The use of functional magnetic resonance imaging and MR tractography for neuropsychiatirc studies of cognitive functions
Ibrahim, Ibrahim ; Hájek, Milan (advisor) ; Vymazal, Josef (referee) ; Žižka, Jan (referee)
5. Summary Although conventiona! MR imaging techniques play a crucia! role in the examination of the centra!nervous system (CNS), these techniques can not give any information about functiona! properties of the brain tissue. Besides conventional MRl techniques, however, there are some MR methods enabling evaluation of these functiona! properties. These methods include functiona! magnetic resonance imaging (!MRl), diffusion-weigbted imaging (DWI) or diffusion tensor imaging (DTI), and voxel based morphometry (VBM). fMRI is a method monitoring the activity of the individua! parts of the brain duriog specific tasks and thus c1arifying their functions. fMRI has become the method of choice especia!ly in neurosurgica! procedures plarming, when it is necessary to know the relative location of the pathological lesion and to localize functiona!ly important areas of the cerebra! cortex, and thereby to reduce the risk of damage associated with the neurosurgical operations. DWI and DT[ are very important methods that may be used to assess the severity of cerebra! ischemia and the integrity ofwhite matter tracts based on diffusion properties ofthe brain tissue. Voxel·based morphometry (VBM) is an objective method and fuHy automated whole brain structura! ana! ysis. Neuropathological changes in the brain tissue of...
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Application of Diffusion Tensor Imaging to Brain Gray and White Marker
Rulseh, Aaron Michael ; Vymazal, Josef (advisor) ; Hluštík, Petr (referee) ; Hájek, Milan (referee)
Application of Diffusion Tensor Imaging to Brain Gray and White Ma er A In the present work we explore the gray and white ma er applicability of diffusion tensor imaging (DTI). To evaluate effect of ferritin-bound iron on gray ma er contrast in DTI, we created an in vitro model consisting of agarose gel phantoms doped with ferritin, and validated our results in vivo on healthy volunteer subjects - years of age in the basal ganglia. We further explored the application of DTI to amyotrophic lateral sclerosis (ALS) and multiple system atrophy (MSA); neurodegenerative diseases with gray and white ma er pathophysiological components. In the ALS study, patients and age- and sex-matched controls were recruited, while the MSA study included probable MSA subjects ( MSA-P, MSA-C) and age- and sex-matched controls. We found that ferritin-bound iron may make a signi cant contribution to DTI scalars in gray ma er regions of the brain, mediated by eigenvalue repulsion. is has important implications for DTI studies targeting gray ma er regions, especially in adolescence and in diseases associated with altered brain-iron load. In ALS, we found altered diffusion in the corona radiata and callosal body, and changes in R in the caudate nucleus and frontal white ma er. In MSA, we observed widespread white ma er changes associated...
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Magnetic resonance volumetric techniques in monitoring disease activity in patients with multiple sclerosis
Andělová, Michaela ; Horáková, Dana (advisor) ; Vymazal, Josef (referee) ; Hluštík, Petr (referee)
Clinical course of multiple sclerosis (MS) is heterogenous and white matter lesion count and volume on brain magnetic resonance imaging (MRI) correlate with clinical course only partially. Therefore, there is an urgent need for more reliable prognostic biomarkers. This work explored three imaging markers - spinal cord (SC) imaging (specifically SC volume measurement and assessment of focal and diffuse SC changes), atlas-based model of "disconnectome" (i.e. disruption of brain connectivity due to white matter lesions) and periventricular white matter gradient assessed with T1 relaxometry. For the SC projects, we assessed MRI from 2044 MS patients with a semi-automatic method for SC volume measurement. We confirmed (i) a relationship between diffuse SC changes, SC volume and disability; (ii) a novel finding was that in patients with EDSS ≤ 4.0, diffuse changes contributed to higher disability more than SC volume; (iii) SC volume explains the paradox in patients with dissociation between brain white matter lesion load and disability; (iv) SC focal and/or diffuse changes are present in 75% patients with early MS, of which 43% have diffuse changes that are related to brainstem lesions. In the disconnectome project, we evaluated the disruption of connectivity caused by white mater lesions in 745 patients...
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The therapeutic benefit of the repetetive transcranial magnetic stimulation on the specific symptoms of schizophrenia
Novák, Tomáš ; Horáček, Jiří (advisor) ; Vymazal, Josef (referee) ; Rektorová, Irena (referee)
The therapeutic benefit of the repetetive transcranial magnetic stimulation on the specific symptoms of schizophrenia Tomas NOVAK Prague Psychiatric Center Summary Transcranial magnetic stimulation is the modern non-invasive method based on the principle of electromagnetic induction. The TMS is widely used in research, diagnostics and treatment of neuropsychiatric disorders. Previous studies imply that repetetive TMS (rTMS) might be useful also in the treatment of some specific symptoms of schizophrenia. The thesis consists of three studies focused on the evaluation of the therapeutic effect of rTMS on specific symptoms of schizophrenia, particularly on negative symptoms and auditory hallucinations. Study 1. The double-blind sham-controlled study of high-frequency rTMS (20Hz) for negative symptoms in schizophrenia The high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) over the prefrontal cortex is a promising method for the treatment of negative symptoms of schizophrenia. Using double-blind, sham- controlled, parallel design, we evaluated the effect of HF-rTMS over the left dorsolateral prefrontal cortex (DLPFC) on negative symptoms in patients with schizophrenia. Sixteen schizophrenia patients with predominantly negative symptoms on stable antipsychotic medication were treated with 20Hz...
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Complex Preoperative Brain Tumor Imaging
Tupý, Radek ; Ferda, Jiří (advisor) ; Vymazal, Josef (referee) ; Tüdös, Zbyněk (referee)
Title Complex preoperative brain tumor imaging Abstract The differentiation of glioblastoma, metastases and brain lymphoma using modern diagnostic imaging methods has a major impact on the strategy of further diagnostic examinations and treatment. In a group of 67 patients with glioblastoma and 31 with cerebral metastasis, the ability to differentiate them according to the evaluation of perfusion parameters changes in peritumoral white matter by T1 dynamic post-contrast magnetic resonance imaging was verified, with the positive predictive value in glioblastoma detection up to 91%. In a group of 36 brain lymphoma patients the importance of imaging submodalities and contribution of a complex magnetic resonance imaging protocol to detect lymphoma up to 80% were evaluated. Key words brain, glioblastoma, lymphoma, magnetic resonance imaging, neoplasm metastasis
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Somatomotor and somatosensory modulation of pain in the EEG and fMR image
Vrána, Jiří ; Stančák, Andrej (advisor) ; Vymazal, Josef (referee) ; Jech, Robert (referee) ; Hájek, Milan (referee)
Pain processing is modulated at different levels of the central nervous system by concurrent sensory and motor processes. From previous studies with innocuous somatosensory evoked potentials we know of the phenomenon of gating by movement. The classical explanation [Melzack R, Wall PD. Pain mechanisms: a new theory. Science 1965;150(699):971-979.] of the mechanism of gating in the posterior horn of spinal cord is complemented by other, lesser understood data, suggesting supraspinal mechanisms. A similar lack of understanding of the cortical mechanisms is seen in pain modulating methods using concurrent electrical nerve stimulation. This work is intended to further our understanding of the cortical mechanisms of pain modulation in the specific cases of (a) isometric muscle contraction of the right or left hand during painful electrical intraepidermal stimulation of the right index finger and (b) during observation of the acute effects of concurrent innocuous median nerve stimulation on painful tonic thermal stimulation of the thenar eminence.
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