Дисертації з теми "Brain parenchyma"
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Berengeno, Andrea Lorena. "Impact of unconjugated bilirubin on brain parenchyma of the Gunn rat." Doctoral thesis, Università degli studi di Trieste, 2011. http://hdl.handle.net/10077/4601.
Повний текст джерелаIn infants and in the Crigler-Najjar syndrome type I patients, severe hyperbilirubinemia due to high levels of unconjugated bilirubin (UCB) may cause Kernicterus, leading to an irreversible and selective brain damage. The Gunn rat is the animal model for the study of these pathologies. It has been suggested that different enzymes of the phase I (cytochrome P-450-dependent mixed function oxygenases 1A1, 1A2, 2A3), phase II (glutathione-S-transferases α2, α3, µ3, µ4, π) and phase III transporters (particularly, Mrp1) seems to be involved in UCB detoxification pathways. However, to date, their in vivo brain expression has been evidenced only at the blood-brain interfaces, while remains largely unexplored in brain parenchyma. Particularly for Mrp1, in vitro evidence reported a role of this transporter in protection of neural primary cultures from dissected cortex, by extruding bilirubin out of the cell. The aim of this study is establish the developmental profile of these genes in brain parenchyma, and assess their alteration in hyperbilirubinemic jj animals. Due to the high regional selectivity of UCB-induced neurotoxicity, cerebellum (Cll), striatum (St), hippocampus (Hip) and cerebral cortex (Cx) were chosen for this study. Our results regard the Mrp1 protein in cerebral cortex of normobilirubinemic (JJ) rats showed that its expression varied during the post-natal age, reaching the highest levels at 9 days after birth. No changes were found between JJ and Jj (having a temporary hyperbilirubinemia in the first week of life) rat for all ages analyzed. Similarly, no differences were detected among JJ/Jj and jj (hyperbilirubinemic) rats at P2, P17 and P60, while a significant increase (p < 0.005) was evidenced in P9 jj rats as compared to age-matched JJ animals. Our Mrp1 mRNA analysis in four regions of P9 animals by Real Time-qPCR revealed the absence of differences among Cx, Cll, St and Hip of P9 normobilirubinemic JJ rats. Moreover, no variations between jj and JJ control animals were detected. Regarding the Mrp1 protein expression in the same four regions by Western blot analysis, our results showed that the levels of this transporter in normobilirubinemic JJ rats were lower in Cx, similar in Cll, St and Hip (p < 0.05 vs Cx). Comparing genotypes, a reduction on Mrp1 in jj animals (compared to Mrp1 amount in the same region of JJ pups) was detected in Cll, St, but reached the statistical significance only in Hip (p < 0.05 vs Hip JJ). The analysis of CYPs gene expression in P9 Gunn rats indicate that CYP1A1, 1A2 and 2A3 mRNA were differently expressed among Cx, Cll, St and Hip of JJ rat. Similarly a region-specific modulation of CYPs expression in jj Gunn rats (compared to JJ) was pointed-out. Surprisingly, UCB seems to generate a plateau effect on CYPs mRNA levels among brain regions of jj rats. In P60 JJ Gunn rats the CYPs expression is higher than in P9 animals, with the following pattern among regions: Cx CllSt Hip. A down-regulation (p < 0.05) in St of P60 jj compared to normal animals was observed. Analyzing the GSTs expression in P9 animals, higher variability in the GSTs expression among the four brain areas was evidenced. In hyperbilirubinemic (jj) rats (compared to JJ), statistically relevant down-regulations were detected for GSTα2 (in St;p < 0.05), GSTα3 (in Hip;p < 0.05), µ3 (in Cx;p < 0.01), µ4 (in Cx; p < 0.05) and π (in Cll: p < 0.05); while GSTµ4 was up-regulated in St (p < 0.05). From P9 to P60, in JJ animals: GSTα3 expression increased (13-75-fold depending on the region); while GSTα2 (5-fold), µ3 (p < 0.05), µ4 (2-fold) and π (2-fold) mRNA amounts decreased. In P60 jj Gunn rats, compared to controls (JJ):a relevant up-regulation of GSTα3 was observed in Cll (p < 0.005) and Hip (p < 0.05), while GSTµ3 in jj was down-regulated (p < 0.05). The Mrp1 results obtained in the present in vivo study seems not to be in agreement with the in vitro data reported, to date. Thus, the Mrp1 expression is low in brain parenchyma and bilirubin affect (up-regulation) only marginally the protein amounts in cortex of P9 animals, while in other regions Mrp1 is not modulated, indicating a marginal role in vivo in bilirubin clearance. Similarly, while in liver GSTα2 and α3 act together as ligandin, this seems not happens in brain where the two subunit are expressed at very low levels (P9: α2 77000- α3 1500 fold difference; P60: α2 112000-α3 2200 fold difference with respect to age matched livers). For all genes under analysis, a very complex and variable pattern of expression among brain areas was evidenced. Consequently, no general rules concerning bilirubin-induced modulation could be drawn, as both up and down-regulation were observed. Additionally, in Cx of P9 jj animals, a translational control of Mrp1 might be hypothesized due to a significant increase in Mrp1 protein, without changes in mRNA level. Therefore, the genomic screening made in this work provides the first general overview on the mRNA developmental profiles of several CYPs and GSTs genes in brain parenchyma (specifically Cx, Cll, St and Hip) of normal rats, and of animals suffering from hyperbilirubinemia, underlying the necessity to find functional evidence to finally understand the role of these enzymes associated with the kernicterus and Crigler-Najjar type I syndrome pathologies.
XXIII Ciclo
1978
Simon, Christiane. "Progenitors in the intact brain parenchyma and their reaction towards acute injury." Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-144896.
Повний текст джерелаSimon, Christiane Verfasser], and Magdalena [Akademischer Betreuer] [Götz. "Progenitors in the intact brain parenchyma and their reaction towards acute injury / Christiane Simon. Betreuer: Magdalena Götz." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2012. http://d-nb.info/1024243362/34.
Повний текст джерелаAlbargothy, Nazira. "Pathways of communication between the subarachnoid space and the brain parenchyma : are they relevant to neurodegenerative diseases?" Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/417992/.
Повний текст джерелаPoncelet, Brigitte P. G. "Study of Physiological Motions in the Human Body using Echo-Planar Magnetic Resonance Imaging :From Brain Parenchyma Motion to Coronary Blood Flow." Doctoral thesis, Universite Libre de Bruxelles, 1995. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212549.
Повний текст джерелаSandsveden, Li. "Evaluation of the Robustness of the Brain Parenchymal Fraction for Brain Atrophy Measurements." Thesis, Linköpings universitet, Medicinsk informatik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-105801.
Повний текст джерелаVågberg, Mattias. "Brain parenchymal fraction in healthy individuals and in clinical follow-up of multiple sclerosis." Doctoral thesis, Umeå universitet, Klinisk neurovetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-128697.
Повний текст джерелаBhat, Danish. "Image Registration and Analysis within quantitative MRI to improve estimation of brain parenchymal fraction." Thesis, Linköpings universitet, Institutionen för medicinsk teknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-132973.
Повний текст джерелаBoccazzi, M. "PURINERGIC SIGNALING AND NEUROGENESIS: MODULATION OF ADULT BRAIN SUBVENTRICULAR ZONE CELL FUNCTIONS AND PARENCHIMAL PROGENITORS MULTIPOTENCY." Doctoral thesis, Università degli Studi di Milano, 2014. http://hdl.handle.net/2434/229414.
Повний текст джерелаSantos, Tânia Custódio. "Alterations at the blood-brain barrier and brain parenchyma along brain metastasization of breast cancer." Master's thesis, 2016. http://hdl.handle.net/10451/34359.
Повний текст джерелаDespite the restricted permeability of the blood-brain barrier (BBB), the brain is a privileged organ regarding the appearance of metastases, particularly from breast cancer. Patients with brain metastases from breast cancer have a severe prognosis, rendering this issue a serious oncologic problem that deserves further attention. Therefore, additional studies are required to establish when breast cancer cells cross the brain endothelium and what are the routes used for the transendothelial migration, to understand what is their precise phenotype along the processes of transmigration and establishment of brain metastases, to determine the alterations occurring in brain endothelium, to study how endothelial cells communicate with malignant ones to promote the attraction of malignant cells into the brain vasculature and tumour-associated vascular development. Based on this, we aimed at establishing the temporal profile of breast cancer metastasization to the brain and characterize the metastasizing cells phenotype, as well as, to investigate the vascular events and BBB properties along the process of metastasization to this target organ. In addition, we aimed to assess signalling mechanisms involved in attraction of carcinoma cells into the brain and proliferation in the nervous tissue. To establish the temporal evolution of the players involved in such processes, we used cerebella, cranial hippocampi, and striata of female mice inoculated with 4T1 breast cancer cells sacrificed at 5 hours, 3 days, 7 days or 10 days, and of female mice injected with vehicle (control) sacrificed at 5 hours. Our results showed the presence of brain metastasis of breast cancer at 7-days after inoculation, which increased thereafter. The malignant cells crossed the BBB as mesenchymal cells and, once inside the brain, these cells underwent a complete or partial mesenchymal-epithelial transition to acquire the epithelial characteristics that allow the establishment of new tumours. In addition, the process of brain metastasization of BC contributed to the downregulation of the tight junction protein claudin-5 of brain microvascular endothelial cells, as well as to the entrance of the blood-borne component thrombin in brain parenchyma. On the other hand, hypervascularization in cranial hippocampus appeared to be associated to the process of brain colonization by breast cancer cells. Regarding the role of platelet-derived growth factor B signalling along the process of brain metastasization, we found that this growth factor was expressed by tumour cells and its expression increased during the formation of brain metastasis. Interestingly, a continuous entrance of cysteine-X amino acid-cysteine receptor 4 (CXCR4)-positive cells into the brain parenchyma appeared to occur along the process of brain metastasization of breast cancer. In sum, this study contributes to clarify the time-course and interdependence of the signalling events, BBB breach and phenotypic transition of malignant cells along endothelial transposition and brain metastases establishment by breast cancer cells. Moreover, the demonstration of early cellular and molecular events points to novel targets for modulation in order to prevent metastasis formation and development.
Apesar da barreira hematoencefálica (BHE) ter uma permeabilidade restrita, o cérebro é um órgão preferencialmente afetado pelo aparecimento de metástases, particularmente de cancro mama. Pacientes com metástases cerebrais provenientes do cancro da mama têm um prognóstico severo, tornando a metastização num sério problema oncológico que merece toda a atenção. Por este motivo, novos estudos são necessários para estabelecer quando é que as células cancerígenas da mama atravessam o endotélio cerebral e quais são as vias que utilizam para migrarem através do endotélio, para se perceber qual o fenótipo que têm ao longo dos processos de migração para dentro do encéfalo e durante o estabelecimento de metástases, para determinar as alterações que ocorrem no endotélio cerebral, para estudar como as células endoteliais comunicam com as células malignas para promover a atracão das células cancerígenas da mama para a vasculatura do encéfalo e o desenvolvimento vascular associado ao tumor. Com base nisto, tivemos com objetivos estabelecer o perfil temporal da metastização do cancro da mama para o encéfalo e caracterizar o fenótipo destas mesmas células, assim como, estudar as alterações vasculares e as propriedades da BHE ao longo do processo de metastização para este órgão secundário. Para além disso, também pretendíamos avaliar os mecanismos de sinalização envolvidos na atracão das células tumorais para o encéfalo e na proliferação no tecido nervoso. Para estabelecer a evolução temporal dos intervenientes envolvidos em tais processos, utilizámos cerebelos, hipocampos craniais e estriados de ratinhos fêmea inoculados com células cancerígenas da mama 4T1 sacrificados às 5 horas, 3 dias, 7 dias, ou 10 dias, e de ratinhos fêmea injetados com veículo (controlo) sacrificados às 5 horas. Os nossos resultados mostraram a presença de metástases cerebrais do cancro mama 7 dias após a inoculação, aumentando ao longo do tempo. As células malignas atravessaram a BHE como células mesenquimais e, uma vez dentro do encéfalo, estas células sofreram uma transição completa ou parcial de fenótipo mesenquimal para epitelial para adquirirem as características epiteliais necessárias para o estabelecimento de novos tumores no encéfalo. Além disso, o processo de metastização cerebral do cancro da mama contribuiu para a diminuição da expressão da proteína das junções de oclusão claudina-5 nas células endoteliais microvasculares cerebrais, assim como para a entrada do componente sanguíneo trombina no parênquima cerebral. Por outro lado, o aumento de vascularização no hipocampo cranial aparentou estar associado ao processo de colonização do encéfalo pelas células cancerígenas da mama. Relativamente ao papel da sinalização do fator de crescimento B derivado de plaquetas ao longo do processo de metastização cerebral, descobrimos que as células tumorais expressavam este fator de crescimento e que a sua expressão aumentou durante a formação de metástases no encéfalo. Curiosamente, a entrada contínua de células que expressam o recetor CXCR4 para dentro do parênquima cerebral aparentou ocorrer ao longo do processo de metastização cerebral do cancro da mama. Deste modo, este estudo contribui para clarificar o curso temporal e a interdependência de vias de sinalização, a quebra da BHE e a transição fenotípica das células malignas ao longo na transposição do endotélio e estabelecimento de metástases cerebrais pelas células cancerígenas da mama. Além disso, a demonstração dos eventos celulares e moleculares iniciais aponta para novos alvos para modulação de modo a prevenir a formação e desenvolvimento de metástases.
This study was supported by Fundação para a Ciência e Tecnologia (FCT – UID/DTP/04138/2013), Portugal, and by National Research, Development and Innovation/Hungarian Scientific Research Fund (NKFIH/OTKA – K-100807 and K-116158), Hungary.
Ju, Shau-Wei, and 朱邵威. "Automatic Vector Seeded Region Growing for Parenchyma Classification in Brain MRI." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/71352922053858606292.
Повний текст джерела國立勤益科技大學
電子工程系
98
Making use of magnetic field theory, magnetic resonance imaging (MRI) which employs pulses radio waves and intense magnetic fields to vibrate hydrogen atoms in the body is a method of obtaining computer images. After long-term clinical trials, MRI has been proved to use in humans harmlessly because of its advantages of non-invasive and non-radiation. In addition, MRI provides cross-sectional images of the objective and scans with different frequency. In light of the procedure, it will generate the difference in strength characteristics, combining powerful imaging sequence changes to provide abundant organization information, which is the key to use computer algorithms to reduce the burden on physician interpretation. How to use computer to decrease processing time is the point, comparing to burden of the physicians diagnosis. In this study, the automatic vector seed region growing is applied in the brain MRI classification. First, vector seed is selected automatically. Second, base on seed regional growth, brain is segmented in detailed. Finally, using K-mean to classify the brain segmentation images, according to gray matter, white matter, and cerebral spinal fluid. When physicians face many images, automatic analysis of medical images become the most challenging task. Nowadays automatic vector seed region growing which is proposed can be the reference for many researchers because it can decrease processing time particularly. This approach makes physicians’ diagnosis acute and effectiveness. Compare to K-means and FMRIB’s Automated Segmentation Tool, FAST, the classified statistics of AVSRG is above all else. To prove the automatic classification results Vector seeds of regions growing, using the receiver operating characteristic analysis to evaluate classification performance, and prove its superiority.
Chen, Ting-Yi, and 陳婷儀. "Identification of Normal Brain Parenchyma by Using Support Vector Machine and MR Perfusion Parameters." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/h6dahx.
Повний текст джерела國立陽明大學
生物醫學影像暨放射科學系
102
Background: Brain perfusion parameters are altered by the presence of stenosis or occlusion of internal carotid artery. A lesion can’t be distinguished from normal tissue by using a single perfusion parameter perfectly because the parameter values varied with the components of different brain tissues. The distinct distributions of lesion and normal brain parenchyma in a scatter plot with two parameters can be separated by support vector machine (SVM) with an optimal dividing line. According to the algorithm, the mask of normal brain parenchyma can be identified. Material and method: We retrospectively analyzed 7 cases with severe unilateral internal carotid artery stenosis. Six combinations of perfusion parameters were choosing from all scatter plots for classification by SVM. Sifting the best combination for SVM to identify normal brain parenchymal mask, and then the mean values of perfusion parameters of the mask calibrated with standard values from literature. The scaling factors were applied to whole brain to calculate the absolute perfusion parameters. Two different approaches for identification of normal brain masks, the contralateral cerebral hemisphere and the median of time to peak (TTP), were compared with SVM to evaluate the accuracy of normal brain masks. Result: Tmax-TTP scatter plot provided the best result with classification by SVM. The percentage of difference between absolute values of perfusion parameters and standard values demonstrated the superiority of SVM. Conclusion: The accuracy of normal brain mask identified by SVM can improve the absolute values of brain perfusion parameters.
Beggs, Clive B., C. P. Chung, N. Bergsland, P. N. Wang, Simon J. Shepherd, C. Y. Cheng, Michael G. Dwyer, H. H. Hu, and R. Zivadinov. "Jugular venous reflux and brain parenchyma volumes in elderly patients with mild cognitive impairment and Alzheimer's disease." 2013. http://hdl.handle.net/10454/9626.
Повний текст джерелаTo determine whether or not jugular venous reflux (JVR) is associated with structural brain parenchyma changes in individuals with mild cognitive impairment (MCI) and Alzheimer's disease (AD). 16 AD patients (mean (SD): 81.9 (5.8) years), 33 MCI patients (mean (SD): 81.4 (6.1) years) and 18 healthy elderly controls (mean (SD): 81.5 (3.4) years) underwent duplex ultrasonography and magnetic resonance imaging scans to quantify structural brain parenchyma changes. Normalized whole brain (WB), gray matter (GM) and white matter (WM) volumes were collected, together with CSF volume. JVR was strongly associated with increased normalized WB (p = 0.014) and GM (p = 0.002) volumes across all three subject groups. There was a trend towards increased WB and GM volumes, which was accompanied by decreased CSF volume, in the JVR-positive subjects in both the MCI and AD groups. When the MCI and AD subjects were aggregated together significant increases were observed in both normalized WB (p = 0.009) and GM (p = 0.003) volumes for the JVR-positive group. No corresponding increases were observed for the JVR-positive subjects in the control group. Through receiver operating characteristic analysis of the brain volumetric data it was possible to discriminate between the JVR-positive and negative AD subjects with reasonable accuracy (sensitivity = 71.4%; specificity = 88.9%; p = 0.007). JVR is associated with intracranial structural changes in MCI and AD patients, which result in increased WB and GM volumes. The neuropathology of this unexpected and counterintuitive finding requires further investigation, but may suggest that JVR retrogradely transmits venous hypertension into the brain and leads to brain tissues swelling due to vasogenic edema.
Fergus, Andrea H. "Regulation of parenchymal microvessels in the brain by endogenous neurotransmitters /." 1997. http://wwwlib.umi.com/dissertations/fullcit/9724640.
Повний текст джерелаDyrna, Felix. "Systematic ultrastructural analyses of meningeal and parenchymal vessels of the central nervous system." 2018. https://ul.qucosa.de/id/qucosa%3A33633.
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