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Bautista, Cynthia A. "Survivorship of a low-grade glioma brain tumor /." View online ; access limited to URI, 2004. http://0-wwwlib.umi.com.helin.uri.edu/dissertations/dlnow/3135892.
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Dave, Nimita D. "Brain/Brain Tumor Pharmacokinetics and Pharmacodynamics of Letrozole." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1368013158.
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Hunt, G. "The metastatic inefficiency of malignant glioma." Thesis, University of Newcastle Upon Tyne, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377441.
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Munson, Jennifer Megan. "Novel nanocarriers for invasive glioma." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41226.
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The invasive nature of glioblastoma (GBM) represents a significant challenge to the standard of care and contributes to poor clinical outcomes. Invasion of tumors into healthy brain restricts chemotherapeutic access and complicates surgical resection. The central hypothesis of the thesis is that an effective anti-invasive agent can enhance the standard chemotherapeutic response in invasive brain tumors. Through a screen of novel compounds, a new anti-invasive small molecule, Imipramine Blue (IB), was identified. This triphenylmethane compound inhibits invasion of highly invasive glioma in vitro and in vivo. To elicit a response in vivo, Imipramine Blue was liposomally encapsulated to yield better delivery to tumor. Using this formulation, it is shown that IB attenuates invasion of glioma in vivo leading to a more compact tumor in an aggressively invasive rodent glioma model. Further, it is shown that this novel compound binds NADPH oxidases and alters expression of actin regulatory elements to elicit this anti-invasive activity. To test our hypothesis that anti-invasive therapy coupled with chemotherapy will enhance efficacy, nano-IB therapy was followed by liposomally encapsulated doxorubicin (DXR) chemotherapy. Additionally, a co-encapsulated formulation of IB and DXR was developed and tested in vivo. This combination therapy significantly enhanced survival compared to IB or DXR alone, resulting in long-term survival in the syngeneic invasive rat astrocytoma model RT2. It was seen that sequential treatment was more effective than the co-encapsulated treatment indicating a benefit of pre-treating the tumor with the anti-invasive. This thesis demonstrates that novel anti-invasive IB mediated 'containment' of diffuse glioma significantly enhances the efficacy of DXR chemotherapy compared to chemotherapy or anti-invasive therapy alone.
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Safdar, Shahana. "Peptide-targeted nitric oxide delivery for the treatment of glioblatoma multiforme." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45797.
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Glioblastoma multiforme (GBM) is the most common malignant central nervous system tumor. The ability of glioma cells to rapidly disperse and invade healthy brain tissue, coupled with their high resistance to chemotherapy and radiation have resulted in extremely poor prognoses among patients. In recent years, nitric oxide (NO) has been discovered to play a ubiquitous of role in human physiology and studies have shown that, at sufficient concentrations, NO is able to induce apoptosis as well as chemosensitization in tumor cells. This thesis discusses the synthesis and characterization of targeted NO donors for the treatment of GBM.
Two glioma targeting biomolecules, Chlorotoxin (CTX) and VTWTPQAWFQWVGGGSKKKKK (VTW) were reacted with NO gas to synthesize NO donors. These NO donors, CTX-NO and VTW-NO, released NO for over 3 days and were able to induce cytotoxicity in a dose dependent manner in glioma cells. The biggest advantage, a result of the targeted delivery of NO, was that the NO donors did not have toxic effects on astrocytes and endothelial cells. To characterize the chemosensitizing effects of CTX-NO, cells were incubated with CTX-NO prior to exposure to temozolomide (TMZ) or carmustine (BCNU). These drugs are the most popular chemotherapeutics used in the treatment of GBM, but have only shown modest improvements in patient survival. Viability studies showed that CTX-NO selectively elicited chemosensitivity in glioma cells, whereas the chemosensitivty of astrocytes and endothelial cells remained unaffected. Further investigation showed that CTX-NO pretreatment decreased O6-methylguanine DNA methyltransferase (MGMT) and p53 levels, suggesting that a decrease in DNA repair ability may be the mechanism by which chemosensitivity is induced.
Lastly, the effects of CTX-NO on glioma cell invasion and migration were studied using Boyden chamber and modified scratch assays. Non-toxic doses of CTX-NO decreased glioma cell invasion in a dose dependent manner. Studies quantifying matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) surface expression demonstrated that while MMP-2 expression was decreased by both CTX and CTX-NO, MMP-9 expression was decreased only by CTX-NO. Furthermore quantifying MMP-2 and MMP-9 activity levels showed that NO and CTX work synergistically to decrease the activity of the enzymes. These studies demonstrate that the decrease in glioma invasion resulting from CTX-NO treatment was partially a consequence of decreased levels of surface and activated MMP-2 and MMP-9. The work presented in this thesis describes a novel approach to treating GBM that can be modified to develop treatments for various other tumors. Furthermore this is the first study to develop glioma-targeting NO donors.
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Clark, Aaron J. "The Expression and Function of Wilms' Tumor 1 in Malignant Glioma." VCU Scholars Compass, 2006. http://hdl.handle.net/10156/1665.
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Roller, Benjamin Thomas. "A nanoencapsulated visible dye for intraoperative delineation of brain tumor margins." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42805.
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Brain and central nervous cancer presents a significant clinical burden, accounting for 2.4% of all cancer deaths. High grade glioma is particularly deadly, with 5 year survival times of 35% or less. Traditional treatment includes tumor resection followed by radiation therapy or chemotherapy. Aggressive resection is essential in order to prolong patient life. In fact, several studies have shown that life expectancy increases with increased extent of resection. Extent of resection is burdened by the fact that surgeons must be careful not to remove functional brain tissue.
Resection is incomplete more often than not due to lack of visual cues for the surgeon. He must rely on tactile sensation to distinguish tumor from healthy tissue. Methods such as intraoperative MRI and CT exist, but these require expensive equipment and special training that is not available in all surgical environments. Some laboratories have proposed small molecule dyes to solve this problem, but these are insufficient when used in an invasive tumor model. It was the goal of this research to provide an objective cue in the form of a nanoencapsulated visible dye without the need for additional equipment of changes to the surgery process itself other than injection of the dye.
We hypothesized that the nanocarrier would allow staining of the tumor through passive targeting by taking advantage of the enhanced permeability and retention effect. Once the nanocarriers have reached the desired target, they would not diffuse out into healthy tissue due to their large size compared to small molecule dyes, which readily diffuse out and stain healthy tissue.
To test this hypothesis, we prepared and characterized a liposomal nanocarrier encapsulating Evans blue dye. The nanocarrier was tested for safety in vitro and in vivo, then used to delineate tumor margins in an invasive rat glioma model in vivo. Microscopic analysis was then conducted to ensure only tumor tissue was stained by the nanocarrier. This thesis presents a successful method of tumor border delineation to provide surgeons with positive visual cues without the need for changes in surgical environment or techniques.
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Felefly, Tony. "Quantum-classical machine learning for brain tumor imaging analysis." Electronic Thesis or Diss., Strasbourg, 2024. http://www.theses.fr/2024STRAJ064.
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La caractérisation des tumeurs cérébrales par des techniques non invasives est nécéssaire. L'objectif est d'utiliser l'apprentissage automatique et la technologie quantique sur des imageries pour caractériser les tumeurs cérébrales. Nous développons un Réseau Neuronal Quantique en utilisant la radiomique des IRM cérébrales pour différencier métastases et gliomes de haut grade. Nous sélectionnons les variables en se basant sur l'information mutuelle et nous utilisons D-Wave pour la solution. Nous entraînons le modèle sur un Simulateur Quantique. Nous utilisons les valeurs de Shapley pour expliquer les prédictions. Nous comparons les résultats á deux modèles classiques performants, DNN et XGB. Le modèle montre une performance comparable. Ensuite, nous développons un Réseau Neuronal Convolutif 3D en utilisant des TDM cérébrales non injectées pour identifier les patients ayant des métastases cérébrales. Nous avons construit deux cohortes de patients, une avec des métastases cérébrales, et une sans anomalies cérébrales. Le cerveau a été segmenté automatiquement. Nous entraînons plusieurs modèles, et le meilleur a montré une bonne performance<br>Brain tumor characterization using non-invasive techniques is eagerly needed. The objective of this thesis is to use advanced machine learning techniques and quantum technology on brain medical images to characterize brain tumors. First, we built a Quantum Neural Network using radiomic features from on brain MRI to differentiate between metastases and gliomas. We used a Mutual Information feature selection technique, and solved the resulting heuristic on D-Wave’s Quantum Annealer. We trained the model on a Quantum Simulator. We employed instance-wise Shapley values to explain the model predictions. We benchmarked the results against two state-of-the-art classical models, Dense Neural Network and Extreme Gradient Boosting. The model showed comparable performance.Second, we developed a 3D Convolutional Neural Network using non-enhanced brain CT scans to identify patients with brain metastases. For this purpose, we curated two cohorts of patients, one with brain metastases, and one without brain abnormalities. The brain was automatically segmented. We trained several versions of the model, and the best model showed an impressive performance
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Woxius, Jonathan. "Att tvingas dela hjärna med en inkräktare : En undersökning av den psykologiska aspekten av att leva med en hjärntumör." Thesis, Högskolan i Halmstad, Akademin för hälsa och välfärd, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-42197.
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Bakgrund: Primär malign hjärntumör medför en tung symtombörda som yttrar sig i en stor variation av fysiska, kognitiva och neurologiska symtom som berör patientens funktionsförmåga och psykiska välmående. Utöver den emotionella och existentiella påfrestningen av att leva med en cancersjukdom ingår hos hjärntumörsjuka patienter även en sviktande kognitiv komponent. Syfte: Syftet med denna litteraturöversikt var att belysa psykologiska påfrestningar för vuxna patienter med primär malign hjärntumör. Metod: Studien utfördes som en allmän litteraturöversikt där tiovetenskapliga kvalitetsgranskades och analyserades för att sedan delas in i tre stycken övergripande teman. Resultat: Det första temat, Osäkerheten i prognosen, belyser den ovisshet som uppstod till följd en oförutsägbar framtid och behovet av mer information gällandes behandlingsmöjligheter och vilka symtom som kan väntas drabba dem. Temat Psykosociala konsekvenser beskriver hur patienter kände att de förlora sig själva i sjukdomen på grund av minnespåverkan, personlighetsförändringaroch en oförmåga att upprätthålla den livsstil som de tidigare haft. Gemensamt bland de sjuka var en rädsla för att vara en börda för dem i patientens närhet och en oro om att förlora sin självständighet. Den existentiella konfrontationen talar om de oundvikliga tankarna om döden och om hoppets betydelse.<br>Background: Primary malignant brain tumor carries a heavy symptom burden that presents itself in a big variation of physical, cognitive and neurological symptoms that affects the patients functioning and psychological wellbeing. Along with the emotional and existential stress of living with cancer, patients diagnosed with brain cancer also suffer from cognitive dysfunction. Purpose: The aim of this study was to illustrate the psychological strain of adult patients living with primary malignant brain tumor. Method: The study was executed as a general literature review based on ten scientific articles. The articles were quality-tested and analyzed to later be sorted into three main themes. Results: The first theme, The uncertainty in the prognosis, illuminate the uncertainty that occurred due to an unpredictable future and the need of information concerning treatment options and what symptoms to expect. The theme The psychosocial consequences, describes how the patients felt as though they had lost themselves to the disease due to memory loss, personality disorders and the inability to maintain the lifestyle they previously had. The patients shared a fear of being a burden to the people around them and a concern of losing their independency. The existential confrontation speaks about the inevitable thoughts of death and the importance of hope.
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Nuthalapati, Silpa. "PRECLINICAL PHARMACOKINETIC AND PHARMACODYNAMIC EVALUATION OF NEW ANTICANCER AGENTS FOR BRAIN TUMOR CHEMOTHERAPY." Diss., Temple University Libraries, 2012. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/181390.
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Pharmaceutical Sciences<br>Ph.D.<br>Glioblastoma multiforme (GBM) is the most common malignant primary brain tumor in adults for which overall prognosis remains poor despite recent treatment advances, thus emphasizing the need for developing effective therapeutic agents. Styryl sulfones belong to a class of non-ATP competitive antineoplastic agents in early stage clinical trials. Detailed investigation of the pharmacokinetics (PKs) and pharmacodynamics (PDs) of novel agents in the preclinical stage plays a pivotal role in drug development that could be applied to guide clinical trials. The main goal of the project was to undertake comprehensive PK and PD evaluation of new agents for brain tumor therapy and in the process establish a PK/PD strategy for the development of such novel agents. The current project was aimed to evaluate the potential of a styryl benzyl sulfone compound, ON01910.Na, as a chemotherapeutic agent for the treatment of GBMs using PK/PD approaches. First, the systemic pharmacokinetics of ON01910 was characterized following single dose intravascular administration of ON01910.Na in healthy mice over a 50-fold dose range of 5 mg/kg - 250 mg/kg. Secondly, an evaluation of the brain and brain tumor disposition of ON01910 was conducted in an orthotopic U87 glioma model in mice using a steady-state dosing regimen, and, in addition, using the same brain tumor model its pharmacodynamic and antiangiogenic activity were determined following multiple dosing. ON01910 exhibited nonlinear pharmacokinetics in the dose range of 50 mg/kg - 250 mg/kg. It showed inadequate brain and brain tumor penetration and insignificant antiangiogenic and antiproliferative activity. The limited brain tumor penetration and activity of ON01910 in the intracerebral glioma model led to the evaluation of ON013105, a prodrug of its more lipophilic anticancer congener, ON013100. A similar PK/PD approach as for ON01910.Na was applied wherein systemic pharmacokinetic properties of ON013105 and its active form, ON013100 in healthy mice, as well as an analysis of their brain and brain tumor distribution following steady-state dosing regimen were determined following administration of prodrug. The active form, ON013100 showed appreciable brain and brain tumor penetration while the prodrug did not. Subsequent pharmacodynamic investigations conducted in vitro identified phosphorylated-ERK (pERK) as a PD marker. To assess time-dependent PK/PD characteristics, mice bearing intracerebral U87 glioma were administered ON013105 at 100 mg/kg intravenously and plasma, brain and brain tumor concentrations of ON013105 and its active form, ON013100 were quantitated as well as tumoral pERK levels. Further, a PK-PD model was developed that characterized plasma, brain and brain tumor concentration-time profiles of ON013105 and ON013100 and tumoral pERK levels. In summary, a PK/PD-driven approach was applied to evaluate and select novel compounds that may have potential in the treatment of brain tumors. The progression of studies yielded one compound, ON013100 that possessed favorable brain tumor distribution and showed PD activity that warrant continued evaluation.<br>Temple University--Theses
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Garcia, Paulo A. "Irreversible Electroporation for the Treatment of Aggressive High-Grade Glioma." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/77269.
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Malignant gliomas (MG), most notably glioblastoma multiforme (GBM), are among the most aggressive of all malignancies. High-grade variants of this type of brain cancer are generally considered incurable with singular or multimodal therapies. Many patients with GBM die within one year of diagnosis, and the 5-year survival rate in people is approximately 10%. Despite extensive research in diagnostic and therapeutic technologies, very few developments have emerged that significantly improve survival over the last seven decades.
Irreversible electroporation (IRE) is a new non-thermal focal tissue ablation technique that uses low-energy electric pulses to destabilize cell membranes, thus achieving tissue death. The procedure is minimally invasive and is performed through small electrodes inserted into the tissue with treatment duration of about one minute. The pulses create an electric field that induces an increase in the resting transmembrane potential (TMP) of the cells in the tissue. The induced increase in the TMP is dependent on the electric pulse parameters. Depending on the magnitude of the induced TMP the electric pulses can have no effect, transiently increase membrane permeability or cause spontaneous death.
In this dissertation we hypothesize that irreversible electroporation is capable of ablating normal (gray and white matter) and pathological (MG and/or GBM) brain tissue in a highly focused non-thermal manner that is modulated through pulse parameters and electrode configuration. Through a comprehensive experimental and numerical investigation, we tested and attained results strongly supporting our hypothesis. Specifically, we developed numerical models that were capable of simulating an entire IRE treatment protocol and would take into account pulse parameters (e.g. duration, frequency, repetition rate and strength) in addition to the dynamic changes in tissue electrical conductivity due to electroporation and joule heating, as well as biologically relevant processes such as blood perfusion and metabolic heat. We also provided a method to isolate the IRE effects from undesired thermal damage in models that were validated with real-time temperature measurements during the delivery of the pulses. Finally we outlined a procedure to use 3D volumetric reconstructions of IRE lesions using patient specific MRI scans in conjunction with the models described for establishing field thresholds or performing treatment planning prior to the surgical procedure; thus supplying the readers with the tools and understanding necessary to design appropriate treatment protocols for their specific application.
Experimentally we presented the first systematic in vivo study of IRE in normal canine brain and the multimodal treatment of a canine MG patient. We confirmed that the procedure can be applied safely in the brain and was well tolerated clinically. The lesions created with IRE were sub-millimeter in resolution and we achieved 75% tumor volume reduction within 3 days post-IRE in the patient. In addition to the sharp delineation between necrotic and normal brain, the treatments spared the major blood vessels, making it appropriate for treatment of tumors adjacent to, or enveloping critical vascular structures. We believe that irreversible electroporation will play a key role in the treatment of intracranial disorders including malignant brain cancer in which the intent is to focally kill undesired tissue while minimizing damage to surrounding healthy tissue.<br>Ph. D.
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Xiong, Anqi. "Novel Regulators of Brain Tumor Development : – From neural stem cell differentiation to in vivo models." Doctoral thesis, Uppsala universitet, Institutionen för immunologi, genetik och patologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-264470.
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Malignant brain tumors are diseases with poor prognosis and/or severe long-term side effects of treatment. This thesis aimed to discover novel regulators in brain tumor development, based on studying neural stem cell and progenitor cell (NSPC) differentiation and using animal models to introduce new insights to mechanisms of human brain tumors. The enzyme heparanase (HPSE) that degrades heparan sulfate (HS) is active in cell signaling and ECM remodeling. In paper I, we found an enhanced differentiation to oligodendrocytes in ES cell-derived NSPCs overexpressing HPSE. Further analysis suggested that this enhanced formation of oligodendrocytes was associated with alterations in receptor tyrosine kinase signaling, and that HPSE might also exert anti-apoptotic functions. Subsequently, in paper II we studied the involvement of HPSE in glioma development. We observed that high HPSE levels associated with poor survival in glioma patients. In experimental models, we found that HPSE promoted glioma growth, and that an inhibitor of HPSE reduced glioma progression both in vitro and in vivo. We hypothesize that regulators in NSPC differentiation could have a potential role in brain tumor development. In paper III, we explored the function of NRBP2, a pseudokinase that is up-regulated during NSPC differentiation. We found low expression of NRBP2 in brain tumors, in comparison to normal brain. In medulloblastoma, in particular, low NRBP2 expression is linked to poor prognosis. Overexpression of NRBP2 in medulloblastoma cells led to impaired cell growth and migration, concomitant with an increased cell death. In paper IV, we searched for novel glioma susceptibility genes by sequencing dog breeds from the same ancestor but with different glioma incidence. In this way we identified three new glioma-associated genes. Two of these are significantly regulated in human glioma and one of those might have a role in glioblastoma stem cell differentiation.
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Zouaoui, Sonia. "Epidémiologie clinique des tumeurs primitives du système nerveux central et en particulier des gliomes." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTT002.
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Les gliomes ont des conséquences dévastatrices. La morbidité et la mortalité sont élevées. Les gliomes représentent un groupe hétérogène complexe d'entités pathologiques et aucune cause n'a été identifiée pour la majorité des gliomes. Les données épidémiologiques varient d'une étude à l'autre. Le nombre de chaque sous-type histologique est trop petit, même pour un grand centre de neurochirurgie, pour permettre une bonne recherche sur chaque sous-type de gliome. Les spécificités oncologiques et cliniques (épilepsie, troubles cognitifs, troubles moteurs, etc.) nécessitent une prise en charge et une analyse spécifique. De plus, il est important de recueillir et d'enregistrer tous les nouveaux cas et le suivi sur une grande région ou un pays entier pour permettre des études fondamentales et cliniques de qualité. En effet, les études en population sont la seule façon de connaitre l'impact en pratique des différentes thérapeutiques effectuées. Les sociétés françaises impliquées en neuro-oncologie (Société Française de Neurochirurgie, Société Française de Neuropathologie, Association des Neuro-Oncologues d'Expression Française) ont récemment créé le Recensement national histologique des tumeurs primitives du système nerveux central (RnhTPSNC) ou French Brain Tumor DataBase (FBTDB) en anglais. L'objectif principal du RnhTPSNC est d'enregistrer de manière prospective tous les cas incidents de tumeur primitive du système nerveux central (TPSNC), en France, pour lesquels le diagnostic histologique est confirmé (1-3). Les objectifs à long terme du RnhTPSNC sont de créer un registre histologique et un réseau national pour : (1) réaliser des études épidémiologiques, (2) mettre en place une base de données pour favoriser toute étude clinique ou fondamentale à grande échelle, (3) permettre l'évaluation des pratiques médicales d'une région ou du pays tout entier, (4) harmoniser et optimiser la prise en charge médicale des patients atteints de TPSNC. La présente étudiante en thèse, Sonia Zouaoui, concentrera son travail sur les gliomes. D'abord, elle devra recueillir les données des patients, puis analyser les facteurs pronostiques, la survie et les prises en charges oncologiques. Deuxièmement, elle participera à l'étude de la répartition géographique des principaux types de gliomes et à la recherche de facteurs de causaux. Troisièmement, elle procédera à un inventaire du matériel cryopréservé disponible pour la réalisation d'études translationnelles<br>Gliomas have devastating consequences. Morbidity and mortality are high. Gliomas represent a complex heterogeneous group of pathologic entities and no underlying cause has been identified for the majority of them. Epidemiologic data vary from study to study. The number of each histological subtype is too small, even for a big neurosurgical center, to allow a good research on each subtype of glioma. Oncological and clinical specificities (epilepsy, cognitive disorders, motor impairments, etc) require a specific care and analysis. Indeed, we need to collect and record all new cases and follow up in large area, to allow good basic and clinical studies. Furthermore, population study is the only way to know what clinicians do to the patients, and make possible evaluating the medical care. The French societies involved in Neuro-Oncology (Société Française de Neurochirurgie, Société Française de Neuropathologie, Association des Neuro-Oncologues d'Expression Française) have recently created the French Brain Tumor DataBase (FBTDB). The main objective of the FBTDB is to prospectively record all primary central nervous system tumors (PCNST), in France, for which histological diagnosis is available (1-3). The long-term goals of the FBTDB are to create a histological national registry and a national network to (1) perform epidemiological studies, (2) implement a new database and use it for setting up both clinical and basic research protocols, (3) allow the evaluation of the medical practices of an area or of the entire country, and (4) harmonize the healthcare of patients affected by PCNST at the higher level. The present PhD student, Sonia Zouaoui, will focus her work on gliomas. First, she will collect data, and will analyze prognostic factors, survival and oncological patterns of care for patients with newly diagnosed glioma in France. Secondly, she will participate in the study of geographical distribution of the main types of glioma and in search of causal factors. Thirdly, she will conduct an inventory of cryopreserved material available for translational research
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Yu, Jennifer. "Bioinformatics Analysis of Vasorin in Gliomas." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1484927314447688.
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Shazeeb, Mohammed Salman. "MRI Contrast Agent Studies of Compartmental Differentiation, Dose-dependence, and Tumor Characterization in the Brain." Digital WPI, 2010. https://digitalcommons.wpi.edu/etd-dissertations/417.
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"Magnetic resonance imaging (MRI) has increasingly become the preferred imaging modality in modern day research to study disease. MRI presents an imaging technique that is practically non-invasive and without any ionizing radiation. This dissertation presents the use of contrast agents in MRI studies to differentiate compartments, to study dose dependence of relaxation times, and to characterize tumors using signal amplifying enzymes in the brain. Differentiating compartments in the brain can be useful in diffusion studies to detect stroke at an early stage. Diffusion-weighted NMR techniques have established that the apparent diffusion coefficient (ADC) of cerebral tissue water decreases during ischemia. However, it is unclear whether the ADC change occurs due to changes in the intracellular (IC) space, extracellular (EC) space, or both. To better understand the mechanism of water ADC changes in response to ischemic injury, making IC and EC compartment specific measurements of water diffusion is essential. The first study was done where manganese (Mn2+) was used as an IC contrast agent. Mn2+ uptake by cells causes shortening of the T1 relaxation time of IC water. The relative difference in T1 relaxation times between the IC and EC compartments can be used to discriminate between the MR signals arising from water in the respective compartments. Mn2+ is also widely used in manganese-enhanced MRI (MEMRI) studies to visualize functional neural tracts and anatomy in the brain in vivo. In animal studies, the goal is to use a dose of Mn2+ that will maximize the contrast while minimizing its toxic effects. The goal of dose study was to investigate the MRI dose response of Mn2+ in rat brain following SC administration of Mn2+. The dose dependence and temporal dynamics of Mn2+ after SC injection can prove useful for longitudinal in vivo studies that require brain enhancement to persist for a long period of time to visualize neuroarchitecture like in neurodegenerative disease studies. Contrast agents, in addition to their use in compartmental differentiation and dose studies, can be used for imaging tumors. The last study in this dissertation focuses on imaging EGF receptors in brain tumors. We tested a novel pretargeting imaging approach that includes the administration of humanized monoclonal antibody (anti-EGFR mAb, EMD72000) linked to enzymes with complementing activities that use a low-molecular weight paramagnetic molecule (diTyr-GdDTPA) as a reducing substrate administered following the mAb conjugates. We analyzed the differential MR tumor signal decay in vivo using orthotopic models of human glioma. The patterns of MR signal change following substrate administration revealed differences in elimination patterns that allowed distinguishing between non-specific and specific modes of MR signal decay. "
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McCready, Jessica. "The Influence of a Single Nucleotide Polymorphism In The Matrix Metalloproteinase-1 Promoter on Glioma Biology." VCU Scholars Compass, 2006. http://scholarscompass.vcu.edu/etd/1123.
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Glioblastomas are an incurable type of brain tumor with a mean survival time of 9-12 months following diagnosis. One of the reasons for this poor prognosis is the ability of tumor cells to invade the surrounding normal brain tissue. Enzymes responsible for this invasive nature include the matrix metalloproteinase family. MMP-1 is a member of this family which has been well studied in many types of invasive tumors, with gliomas being an exception. We studied a single nucleotide polymorphism (SNP) in the MMP-1 promoter that may influence glioma biology. This SNP consists of the presence (2G) or absence (1G) of a guanine nucleotide at position -1607. The additional guanine nucleotide creates a binding site for ETS transcription factors and combined with the AP-1 binding site at position -1602 creates a Ras Responsive Element. We determined that the distribution of the MMP-1 genotype differed significantly between the healthy population and the glioblastoma patient population, with the 2G/2G genotype more prevalent in the glioblastoma patients. In addition, MMP-1 mRNA and protein examined in a select group of patient tissue had significantly higher levels when compared to normal brain controls, however, there was no correlation with genotype. Promoter reporter assays indicated that the 2G promoter was approximately three times more active than the 1G promoter in three different glioma cell lines.We investigated potential signaling mechanisms responsible for increases in MMP-1 transcription due to the presence of the RAS responsive element. Treatment of glioma cell lines with hepatocyte growth factor/scatter factor (HGF/SF) led to significant increases in MMP-1 transcription, via the MAP kinase ERK pathway. AP-1 transcription factor proteins, cJun and cFos were increased in response to HGF treatment but not Ets-1 and ETV-1. HGF/SF treatment of glioma cell lines differing in their MMP-1 genotype affected binding of ETS and AP-1 proteins to the endogenous MMP-1 distal promoter. Using chromatin immunoprecipitation assays, we identified these differentially DNA-bound AP-1 and ETS proteins. The data presented indicate that the MMP-1 SNP (-1607) is important in glioma biology and may contribute to tumor function and future investigations into its role in glioma biology is warranted.
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Mazzara, Gloria Patrika. "Brain tumor target volume determination for radiation therapy treatment planning through the use of automated MRI segmentation." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000600.
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Johansson, Fredrik. "Screening for Candidate Brain Tumor Genes : Identifying Genes that Cooperate with Platelet-Derived Growth Factor in Glioma Development and Progression." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis Univ.-bibl. [distributör], 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7185.
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Lindberg, Nanna. "Cellular Origin and Development of Glioma." Doctoral thesis, Uppsala universitet, Institutionen för genetik och patologi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-109486.
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Gliomas are the most common primary tumors of the central nervous system believed to arise from glial cells. Invasive growth and inherent propensity for malignant progression make gliomas incurable despite extensive treatment. I have developed a life-like orthotopic glioma model and used this and other in vivo models to study basic mechanisms of glioma development and treatment. Previous studies had indicated that experimental gliomas could arise from glial stem cells and astrocytes. The present thesis describes the making and characterization of a novel mouse model, Ctv-a, where gliomas are induced from oligodendrocyte progenitor cells (OPCs). Our study shows that OPCs have the capacity to give rise to gliomas and suggests in light of previous data that the differentiation state of the cell of origin affects tumor malignancy. CDKN2A encodes p16INK4a and p14ARF (p19Arf in mouse) commonly inactivated in malignant glioma. Their roles in experimental glioma have been extensively studied and both proteins have tumor suppressor functions in glial stem cells and astrocytes. Here, we demonstrate that p19Arf only could suppress gliomagenesis in OPCs while p16Ink4a had no tumor suppressive effect. Functional DNA repair is pivotal for maintaining genome integrity, eliminating unsalvageable cells and inhibiting tumorigenesis. We have studied how RAD51, a central protein of homology-directed repair, affected experimental glioma development and have found that expression of RAD51 may protect against genomic instability and tumor development. Angiogenesis, the formation of new blood vessels from pre-existing ones, is a central feature of malignant progression in glioma. Antiangiogenic treatment by inhibition of vascular endothelial growth factor receptor signaling is used in the clinic for treatment of some cancers. We have investigated the effect of an alternative antiangiogenic protein, histidine-rich glycoprotein (HRG), on glioma development and found that HRG could inhibit the formation of malignant gliomas and completely prevent the formation of glioblastoma.
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Bielecki, Peter. "Advanced Mesoporous Silica Nanoparticles for the Treatment of Brain Tumors." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case159558503832021.
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Zhang, Zhihan. "NSEA: n-Node Subnetwork Enumeration Algorithm Identifies Lower Grade Glioma Subtypes with Altered Subnetworks and Distinct Prognostics." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case148595901371196.
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Beccaria, Kévin. "Evaluation de la diffusion intracérébrale des drogues antinéoplasiques après ouverture de la barrière hémato-encéphalique induite par ultrasons : Application aux gliomes malins de l’enfant Brainstem Blood-Brain Barrier Disruption and Enhanced Drug Delivery with an Unfocused Ultrasound Device – A Preclinical Study in Healthy and Tumor-Bearing Mice Ultrasound-Induced Blood-Brain Barrier Disruption for the Treatment of Gliomas and other Primary CNS Tumors Blood-Brain Barrier Disruption with Low-Intensity Pulsed Ultrasound for the Treatment of Pediatric Brain Tumors: A Review and Perspectives." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS044.
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Les gliomes de haut grade représentent près de 15% de l’ensemble des tumeurs cérébrales de l’enfant. Aucun progrès thérapeutique n’a été fait depuis 30 ans et leur pronostic reste effroyable. La barrière hémato-encéphalique (BHE) est l’une des causes de l’échec des traitements médicaux car elle limite le passage de la majorité des molécules vers le cerveau, empêchant la plupart des drogues antinéoplasiques d’atteindre le tissu tumoral. L’ouverture de la BHE par les ultrasons pulsés de faible intensité en association avec des microbulles injectées par voie intraveineuse est une technique qui permet d’ouvrir transitoirement la BHE de manière localisée et sécurisée. Dans cette étude, nous avons confirmé la capacité d’un nouvel agent de contraste (microbulles) à ouvrir la BHE avec des ultrasons. Nous avons par ailleurs montré qu’il était possible d’ouvrir la BHE dans le tronc cérébral avec un dispositif ultrasonore non focalisé (SonoCloud®), à la fois sur des souris saines et des modèles murins de DIPG. Nous avons pu augmenter la distribution de l’irinotécan et du panobinostat dans le tronc cérébral de souris saines et de modèles de DIPG après ouverture de la BHE, sans cependant améliorer la survie de notre modèle de DIPG. Des études préliminaires ont été réalisées avec des inhibiteurs de chekpoints et des cellules natural killer, qui n’ont pas permis d’améliorer la survie d’un modèle murin de gliome malin sus-tentoriel. Enfin, nous avons mis au point le premier essai clinique pédiatrique qui visera, dès le premier semestre 2020, à évaluer la faisabilité et la tolérance de l’ouverture de la BHE avec le dispositif SonoCloud® chez l’enfant et l’adolescent<br>High-grade gliomas represent about 15% of pediatric brain tumors. No progress has been made in the treatment of these tumors during the last decades, and their prognosis remains dismal. The blood-brain barrier (BBB) plays a major role in the failure of medical treatments since it prevents most molecules to reach the brain, thus limiting the delivery of antineoplastic drugs to brain tumors. Disruption of the BBB (BBBD) with low intensity pulsed ultrasound in association with intravenous microbubbles is a technique that allows for safe, transient, and localized opening of the BBB. In this thesis, we confirmed the capacity of a new microbubble contrast agent to induce BBBD with ultrasound. We showed that opening of the BBB in the brainstem is possible with a nonfocused ultrasound device (SonoCloud®), in both healthy mice and a murine model of DIPG. We were able to increase irinotecan and panobinostat delivery in the brainstem of both healthy and tumor-bearing mice after BBBD, but we did not observe increased in overall survival. Preliminary studies have also been performed with checkpoints inhibitors and natural killer cells in a murine model of supra-tentorial high-grade glioma, but we were not able to increase survival in these models anymore. Finally, we prepared the first clinical trial that will evaluate the feasibility and tolerance of ultrasound-induced BBBD with the SonoCloud® device in the pediatric population. This trial will begin during the first semester of 2020
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Mainio, A. (Arja). "Depressive and anxious symptomatology in relation to a primary brain tumor:prospective study of neurosurgical patients in Northern Finland." Doctoral thesis, University of Oulu, 2005. http://urn.fi/urn:isbn:9514277163.
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Abstract
The findings on depression and anxiety among brain tumor patients have so far been based on case series and case samples. In Finland, psychiatric research in relation to psychiatric symptoms among patients with different types of brain tumors is lacking.
The study population of this thesis consisted of 101 patients (39 males and 62 females) aged between 20 and 82 years with a solitary primary brain tumor treated surgically at the Oulu Clinic for Neurosurgery, Oulu University Hospital between February 1990 and March 1992. The major histological subgroup consisted of gliomas (40%), and the rest were meningiomas (33%), acoustic neurinomas (13%), pituitary adenomas (8%) and other types (6%).
The psychiatric symptoms of the patients were assessed at three time points, namely before tumor operation as well as at three months and at one year after operation by two valid measurement instruments, the Beck Depression Inventory and the Crown Crisp Experiential Index. In addition, the patients' functional state was evaluated by the Karnofsky Performance Scale and their quality of life according to Sintonen 15 D.
Prevalence of at least mild depression before tumor operation was 30% for males and 38% for females. The mean depressive scores decreased significantly for up to one-year during follow-up for both males and females, but they remained notably high in all patients. Decreased functional status (KPS under 70) in the patients was significantly associated with high depressive scores at all measurement points. The decrease in the mean depressive scores was significant among patients with an anterior tumor and those with a pituitary adenoma.
Five-year survival of the brain tumor patients was found to be mainly associated with the histology of the tumor. Survival time in months (SD) of the patients with high-grade (III–IV) gliomas was shown to be 22.5 (21.4), while it was 50.2 (19.9) for the patients with low-grade (I–II) gliomas, and 58.2 (9.4) for the rest of the patients. Depression among low-grade glioma patients was significantly associated with worse survival at five years follow-up.
The level of anxiety was shown to be significantly higher among patients with a primary brain tumor in the right hemisphere compared to the anxiety scores among patients with left hemispheric tumors. A significant increase was found in the level of obsessionality over time in the female patients with a brain tumor in the left anterior location of the brain at three months after operation.
The level of quality of life (QOL) was significantly worse among female brain tumor patients compared to males. Depressive females had significantly lower quality of life compared to that of non-depressive females up to one-year follow-up after surgical operation of the tumor.
Depression, anxiety and obsessive-compulsive symptoms have to be recognized and be treated by psychotherapy and pharmacotherapy as soon as possible at every unit where brain tumor patients are followed and encountered.
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Grieger, Wolfgünter Helwig. "Differenzierung von Hirntumoren mittels dynamischer Magnetresonanztomographie." Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2005. http://dx.doi.org/10.18452/15344.
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Die hier verwendete Methode der dynamischen Magnetresonanztomographie (dMRT) erlaubte bei Hirntumorpatienten erstmals, gleichzeitig neben dem regionalen zerebralen Blutvolumen (rCBV) und dem regionalen zerebralen Blutfluß weitere Parameter, wie Permeabilitäten, die interstitiellen Volumina und das Zellvolumen, zu bestimmen. Anhand dieser Parameter sollte erstens geprüft werden, inwieweit diese zu einer besseren Malignitätseinstufung von Hirntumoren beitragen. Zweitens sollte geklärt werden, inwiefern sich die untersuchten Tumorgruppen voneinander unterscheiden lassen. Drittens war es Ziel, ein in-vivo-Grading für die Gliome zu entwickeln. Es wurden 60 Patienten mit verschiedenen Tumoren, wie Gliome, Metastasen, Meningeome und Lymphome, untersucht. Die aus der dMRT-Untersuchung erhaltenen Daten wurden mit einem pharmakokinetischen Modell ausgewertet. Für jeden Patienten wurden die oben genannten Parameter in Form von Bildern dargestellt und quantitativ berechnet. Für die Tumordifferenzierung eignete sich das mittlere rCBV am besten: Innerhalb der Gliome konnte signifikant zwischen den Grad-II- und Grad-III-Gliomen und den Grad-II- und Grad-IV-Gliomen unterschieden werden. Weiterhin konnten die Meningeome signifikant von den anderen untersuchten Tumorentitäten abgegerenzt werden. Das in-vivo-Grading der Gliome erlaubte in 71 % der Fälle eine korrekte Zuordnung zum WHO-Grad. Die Parameterbilder lieferten neben Informationen für die Tumordifferenzierung auch beispielsweise Hinweise auf den heterogenen Tumoraufbau. Des weiteren ermöglichten sie, Narbengewebe gegenüber Tumorgewebe abzugrenzen und Folgen einer Strahlentherapie zu beobachten. Schließlich waren Aussagen über die Gefäßarchitektur und das Wachstum unterschiedlicher Tumorgruppen möglich. Die mit der hier verwendeten Methode der dMRT erhaltenen Parameter boten mehrere Vorteile: Eine Differenzierung einzelner Tumorgruppen war möglich. Für die Gliome konnte mittels des in-vivo-Gradings eine quantitative Malignitätseinschätzung erfolgen. Die gewonnenen Informationen über den heterogenen Tumoraufbau erlauben bessere Biopsieergebnisse. Zusätzlich wurden Hinweise auf die Tumorpathophysiologie erhalten und es erschien möglich Veränderungen nach Therapie zu beobachten.<br>A method of dynamic magnet resonance imaging (dMRI) was used, which allowed for the first time to determine simultaneously several parameters in patients with brain tumors. These parameters were the regional cerebral blood volume (rCBV), the regional cerebral blood flow, and in addition, permeabilities, interstitial volumes, and the cell volume. First, it should be determined to what extent these parameters allow a better classification of the malignancy of brain tumors. Second, it should be evaluated how far it is possible to differentiate the examined tumor groups from each other. Third, a method for an in-vivo-grading specifically for gliomas should be developed. Altogether 60 patients with different tumors such as gliomas, metastasis, meningiomas, and lymphomas were examined. The data of the dMRI examination were evaluated using a pharmacokinetic model. For every patient, the parameters mentioned above were shown in maps and calculated quantitatively. The mean rCBV resulted in the best tumor differentiation: within the group of gliomas it was possible to differentiate significantly between grade-II- and grade-III-gliomas and grade-II- and grade-IV-gliomas. Furthermore, meningiomas were differentiated significantly from the other tumors. In respect to the group of gliomas, the tumor grades determined by the developed in-vivo-grading corresponded with the WHO grade of each glioma in 71 % of the cases. The parameter maps were not only usefull for tumor differentiation, but also yielded information concerning the heterogenous tumor structure. Additionally, these maps allowed to differentiate scar tissue from tumor tissue and effects of a radiotherapy could be observed. Finally, information about the vessel architecture and the growth of different tumor groups could be obtained. The parameters determined by the dMRI method used here offered several advantages: it was possible to differentiate between single tumor groups. For the gliomas, a quantitative malignancy classification resulted from the in-vivo-grading. The information concerning the structure of the heterogeneity of the tumor allows for better biopsy results. Additionally, information was also obtained concerning the pathophysiology of the tumors and it seemed possible to observe changes after a therapy.
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Mohan, Vandana. "Computer vision and machine learning methods for the analysis of brain and cardiac imagery." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/39628.
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Medical imagery is increasingly evolving towards higher resolution and throughput. The increasing volume of data and the usage of multiple and often novel imaging modalities necessitates the use of mathematical and computational techniques for quicker, more accurate and more robust analysis of medical imagery. The fields of computer vision and machine learning provide a rich set of techniques that are useful in medical image analysis, in tasks ranging from segmentation to classification and population analysis, notably by integrating the qualitative knowledge of experts in anatomy and the pathologies of various disorders and making it applicable to the analysis of medical imagery going forward. The object of the proposed research is exactly to explore various computer vision and machine learning methods with a view to the improved analysis of multiple modalities of brain and cardiac imagery, towards enabling the clinical goals of studying schizophrenia, brain tumors (meningiomas and gliomas in particular) and cardiovascular disorders.
In the first project, a framework is proposed for the segmentation of tubular, branched anatomical structures. The framework uses the tubular surface model which yields computational advantages and further incorporates a novel automatic branch detection algorithm. It is successfully applied to the segmentation of neural fiber bundles and blood vessels.
In the second project, a novel population analysis framework is built using the shape model proposed as part of the first project. This framework is applied to the analysis of neural fiber bundles towards the detection and understanding of schizophrenia.
In the third and final project, the use of mass spectrometry imaging for the analysis of brain tumors is motivated on two fronts, towards the offline classification analysis of the data, as well as the end application of intraoperative detection of tumor boundaries. SVMs are applied for the classification of gliomas into one of four subtypes towards application in building appropriate treatment plans, and multiple statistical measures are studied with a view to feature extraction (or biomarker detection). The problem of intraoperative tumor boundary detection is formulated as a detection of local minima of the spatial map of tumor cell concentration which in turn is modeled as a function of the mass spectra, via regression techniques.
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Lagaert, Jean-Baptiste. "Modélisation de la croissance tumorale : estimation de paramètres d’un modèle de croissance et introduction d’un modèle spécifique aux gliomes de tout grade." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14308/document.
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Les travaux présentés dans le cadre de cette thèse traitent de la modélisation mathématique de la croissance tumorale. La première partie de cette thèse traite de l’estimation des paramètres. Plus précisément, il s’agit de déterminer la vascularisation d’une tumeur à partir de sa dynamique. Pour cela, nous générons à partir d’un modèle d’équations aux dérivées partielles l’évolution en temps de la densité de cellules tumorales. Ensuite, nous résolvons des problèmes inverses afin de retrouver la densité de vascularisation correspondante. Nous montrons que la vascularisation estimée permet de prédire efficacement la croissance future de la tumeur. Dans un second temps, nous introduisons une classe de modèles pour la croissance de gliomes qui sont adaptés à la fois aux gliomes de bas grades et aux glioblastomes multiformes. Afin de tenir compte des spécificités des gliomes, le modèle prend en considération le caractère infiltrant de ce type de tumeur ainsi que l’hétérogénéité, l’anisotropie et la géométrie du cerveau. Nos modèles permettent d’étudier l’efficacité des traitements anti-angiogéniques et de la comparer à celle d’un traitement qui inhiberait la capacité d’invasion de gliomes. Les modèles ont été implémentés en 2D et en 3D dans des géométries réalistes obtenues grâce à un atlas<br>This thesis deals with mathematical modeling of tumor growth. Firstly, we present a parameter estimation method. More precisely, it consists in recovering the position of the tumor blood vessel, starting from imaging. The first step is to design a particular vascularization, then we compute the tumor growth with this blood-vessel network by using a model based on partial differential equations and hence we try to recover the initial vascularization solving the inverse problem. We show that the estimated vasculature could be used to efficiently predict the future tumor growth. In the second part of this thesis, we introduce a class of models dedicated to glioma, adapted both to low grade and multiform glioblastoma. In order to take into account their specificities, we include mainly two effects in the model : on the one hand, the infiltrate behaviors of gliomas, and on the other hand, the impact of brain heterogeneity, of brain anisotropy and of brain geometry on the tumor growth. Our models allow us to evaluate the efficiency of anti-angiogenic drugs and to compare it with the effect of drugs inhibiting the invasion ability of glioma. The models have been implemented in 2D and 3D in actual geometry provided by an atlas
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Stretton, Erin. "Simulation de modèles personnalisés de gliomes pour la planification de thérapies." Thesis, Paris, ENMP, 2014. http://www.theses.fr/2014ENMP0064/document.
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Les modèles de croissance tumorale fondés sur l'équation de réaction-diffusion Fisher Kolmogorov FK ont montré des résultats probants dans la reproduction et la prédiction de l'invasion de cellules tumorales du cerveau pour les gliomes. Nous utilisons différentes formulations du modèle FK pour évaluer la nécessité de l’imagerie de diffusion pour construire des modèles spécifiques de Gliomes de Bas Grade GBG, l'étude de l'infiltration de cellules tumorales après une résection chirurgicale de la tumeur, et définir une métrique pour quantifier l’évolution de GBG. L'imagerie en tenseur de diffusion ITD a été suggérée pour modéliser la diffusion anisotrope des cellules tumorales dans la matière blanche du cerveau. Les ITD acquises en basse résolution impactent la précision des résultats des modèles de croissance. Nous utilisons une formulation FK pour décrire l'évolution de la frontière visible de la tumeur pour étudier l'impact du remplacement de l'ITD patient par une hypothèse de diffusion isotrope ou une ITD de référence anisotrope en haute résolution formée par la moyenne des ITD de plusieurs patients. Nous quantifions l'impact du remplacement de l'ITD acquise sur un patient à aide de simulations de croissance tumorales synthétiques et des prévisions d'évolution de la tumeur d'un cas clinique. Cette étude suggère que la modélisation de la croissance du gliome à base de motilité différentielle de tissus donne des résultats un peu moins précis qu'à l'aide d'une ITD. S'abstenir d'utiliser une ITD serait suffisant lors de la modélisation de GBG. Par conséquent, toutes ces options d'ITD sont valides dans une formulation FK pour modéliser la croissance de GBG dans le but d'aider les cliniciens dans la planification du traitement. Après la résection d’une tumeur cérébrale, ils veulent savoir quel serait le meilleur traitement de suivi pour chaque patient : une chimiothérapie pour des tumeurs diffuses ou bien une deuxième résection après un laps de temps donné pour les tumeurs massives. Nous proposons une méthode pour tirer profit de modèles de croissance de gliome FK sur les cas post-opératoires montrant des distorsions du cerveau pour estimer l'infiltration des cellules tumorales au-delà des frontières visibles dans les IRM FLAIR. Notre méthode répond à 2 défis de modélisation : celui du mouvement du parenchyme cérébral après la chirurgie avec une technique de recalage non-linéaire et celui de la segmentation incomplète de la tumeur post-opératoire en combinant 2 cartes d'infiltration : une ayant été simulée à partir d'une image pré-opératoire et l’autre à partir d'une image post-opératoire. Nous avons utilisé les données de 2 patients ayant des GBG afin de démontrer l'efficacité de la méthode. Celle-ci pourrait aider les cliniciens à anticiper la récurrence de la tumeur après une résection et à caractériser l’étendue de l'infiltration non visible par la radiologie pour planifier la thérapie. Pour les GBG visibles par une IRM FLAIR/T2, il y a un débat important au sein du groupe de travail RANO Response Assessment in Neuro-Oncology sur la sélection d'un seuil pertinent des métriques basées sur l’évolution de la taille de la tumeur pour déterminer si la maladie est évolutive ME. Nous proposons une approche pour évaluer la ME du GBG en utilisant des estimations de la vitesse de croissance de la tumeur à partir d'une formulation FK qui prend en compte les irrégularités de forme de la tumeur, les différences de vitesse de croissance entre la matière grise et la matière blanche, et les changements volumétriques. En utilisant les IRM FLAIR de 9 patients, nous comparons les estimations de ME de notre approche proposée avec celles calculées en utilisant les estimations manuelles de la vitesse de croissance tumorale 1D, 2D et 3D et celles calculées en utilisant un ensemble de critères basés sur la taille critères RECIST, Macdonald et RANO. Notre approche est prometteuse pour évaluer la ME du GBG à partir d'un nombre limité d'examens par IRM<br>Tumor growth models based on the Fisher Kolmogorov (FK) reaction-diffusion equation have shown convincing results in reproducing and predicting the invasion patterns of glioma brain tumors. In this thesis we use different FK model formulations to i) assess the need of patient-specific DTIs when modeling LGGs, ii) study cancer cell infiltration after tumor resections, and iii) define a metric to determine progressive disease for low-grade glimoas (LGG).Diffusion tensor images (DTIs) have been suggested to model the anisotropic diffusion of tumor cells in brain white matter. However, patient specific DTIs are expensive and often acquired with low resolution, which compromises the accuracy of the tumor growth models' results. We used a FK formulation to describe the evolution of the visible boundary of the tumor to investigate the impact of replacing the patient DTI by i) an isotropic diffusion map or ii) an anisotropic high-resolution DTI atlas formed by averaging the DTIs of multiple patients. We quantify the impact of replacing the patient DTI using synthetic tumor growth simulations and tumor evolution predictions on a clinical case. This study suggests that modeling glioma growth with tissue based differential motility (not using a DTI) yields slightly less accurate results than using a DTI. However, refraining from using a DTI would be sufficient in situations when modeling LGGs. Therefore, any of these DTI options are valid to use in a FK formulation to model LGG growth with the purpose of aiding clinicians in therapy planning.After a brain resection medical professionals want to know what the best type of follow-up treatment would be for a particular patient, i.e., chemotherapy for diffuse tumors or a second resection after a given amount of time for bulky tumors. We propose a thorough method to leverage FK reaction-diffusion glioma growth models on post-operative cases showing brain distortions to estimate tumor cell infiltration beyond the visible boundaries in FLAIR MRIs. Our method addresses two modeling challenges: i) the challenge of brain parenchyma movement after surgery with a non-linear registration technique and ii) the challenge of incomplete post-operative tumor segmentations by combining two infiltration maps, where one was simulated from a pre-operative image and one estimated from a post-operative image. We used the data of two patients with LGG to demonstrate the effectiveness of the proposed three-step method. We believe that our proposed method could help clinicians anticipate tumor regrowth after a resection and better characterize the radiological non-visible infiltrative extent of a tumor to plan therapy.For LGGs captured on FLAIR/T2 MRIs, there is a substantial amount debate on selecting a definite threshold for size-based metrics to determine progressive disease (PD) and it is still an open item for the Response Assessment in Neuro-Oncology (RANO) Working Group. We propose an approach to assess PD of LGG using tumor growth speed estimates from a FK formulation that takes into consideration irregularities in tumor shape, differences in growth speed between gray matter and white matter, and volumetric changes. Using the FLAIR MRIs of nine patients we compare the PD estimates of our proposed approach to i) the ones calculated using 1D, 2D, and 3D manual tumor growth speed estimates and ii) the ones calculated using a set of well-established size-based criteria (RECIST, Macdonald, and RANO). We conclude from our comparison results that our proposed approach is promising for assessing PD of LGG from a limited number of MRI scans. It is our hope that this model's tumor growth speed estimates could one day be used as another parameter in clinical therapy planning
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Ghasimi, Soma. "Genotype-phenotype studies in brain tumors." Doctoral thesis, Umeå universitet, Onkologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-83185.
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Meningioma and glioma are the most common primary brain tumors, but their etiologies are largely unknown. Although meningioma is usually benign, their intracranial location can lead to lethal consequences, and despite progress in surgery, radiotherapy, and chemotherapy the prognosis for patients with glioma remains poor. The only well-established environmental risk factor for meningioma and glioma is ionizing radiation. Evidence for inherited predisposition to meningioma and glioma is provided by a number of rare inherited syndromes where collectively these diseases account for only a small proportion of the twofold increased risk of brain tumors seen in first-degree relatives for meningioma and glioma patients. It is very possible that much of the excess familial risk is a consequence of co-inheritance of multiple low-risk genetic variations. With this in mind, the aims of the studies in this thesis were to discover genetic risk variants influencing the probability of acquiring the disease and to identify the association between risk variants on the tumor phenotype. To identify genetic variants influencing meningioma risk, a comprehensive tagging of the selected genes in a case-control study was performed. We identified nine risk variants in EGF, ERBB2, and LRIG2 genes. However, these findings could not be confirmed in another larger independent dataset. In addition, the study identified a correlation between LRIG2 protein expression and ER status when analyzed with different parameters. In a separate study with a larger sample of meningioma patients, the same correlation between LRIG2 and ER status was observed. To explore the potential association between reported germline risk variants and somatic genetic events, matched tumor and blood samples from glioma patients were analyzed by SNP array. The results identified correlations between EGFR gene variants and somatic aberrations within the EGFR locus and CDKN2A/B locus. To further study the relationship between germline risk variants and tumor phenotype, the same patient material was used and analyzed by three different techniques: SNP array, IHC, and FISH. The results revealed EGFR risk variants effecting copy number variation of the EGFR gene and the expression of the IDH1 and p53. Further comparison between different techniques such as SNP array and FISH analysis revealed the difficulty in achieving consistent results with different techniques. To summarize, the glioma studies show a link between genotype and phenotype where genetic risk variants in the EGFR gene were found to be associated with specific somatic aberrations. These associations are biologically interesting because EGFR is involved in multiple cellular processes. Additional studies of the direct functional role of these observations need to be conducted to elucidate the molecular mechanisms underlying the identified association between germline gene variants and somatic aberrations. For the meningioma studies, no significant risk variants influencing the disease were found but a correlation between LRIG2 and ER status was observed. This result suggests a potential role for the LRIG protein in the pathogenesis of meningioma, but more studies are needed to confirm this hypothesizes.<br><p>Cancer research foundation in northern Sweden and Lions cancer research foundation at Umeå university</p>
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Agarwal, Abhiruchi. "Nanocarrier mediated therapies for the gliomas of the brain." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39468.
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Existing methods of treating glioma are not effective for eradicating the disease. Therefore, new and innovative methods of treatment alone or in combination with existing therapies are necessary. Delivery of therapeutic agents through delivery carriers such as liposomes diminishes the harmful effects of the agent in healthy tissues and allows increased accumulation in the tumor. In addition, targeted chemotherapy using liposomes provides the opportunity for further increase in drug accumulation in tumor. However, the current targeting strategies suffer accelerated plasma clearance and are not advantageous in improving efficacy. The search for new tumor targets, novel ligands, new strategies for targeting, and particle stabilization will advance our ability to improve delivery at the tumor level while decreasing toxicity to normal tissues.
The global objective of this thesis was to improve the status of current liposomal therapy to achieve higher efficacy in tumors. Here, we show a novel mechanism to increase targeting to tumor while uncompromising on the long circulation of stealth liposomes. Long circulation is essential for passive accumulation of the nanocarriers due to EPR effect, in order to see benefits of targeting. Using phage display technique, a variety of tumor specific peptides were identified for use as targeting moieties. One potential advantage of the approach proposed here is the rapid identification of patient tumor specific peptide that evades the RES. This could lead to the development of a nanocarrier system with high avidity and selectivity for tumors. Therefore, tumor accumulation of the targeted formulations will be higher than that of non‐targeted liposomes due to increased drug retention at the tumor site and uncompromised blood residence time.In addition, it has been shown that the distribution of nanocarriers, spatially within the tumor, is limited that might further hinder the distribution of the encapsulated drug, thereby limiting efficacy. It is necessary to release the drug from within the nanocarrier to promote increased efficacy. Here, we were able to address the problem of drug diffusion within the tumor interstitium using a combination therapy employing a remotely triggered thermosensitive liposomal chemotherapeutic. We fabricated a thermosensitive liposomal nanocarrier that maintained its stability at physiological temperature to minimize toxicity to healthy cells. We, then, showed a remote triggering mechanism mediated by gold nanorods heated via NIR can help in achieving precise control over the desired site for drug release. These strategies enabled increased drug availability at the tumor site and contributed to tumor retardation. Additionally, we show that the synergistic therapy employing gold nanorods and thermosensitive liposomes may have great potential to be translated to the clinic.
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Mörén, Lina. "Metabolomics and proteomics studies of brain tumors : a chemometric bioinformatics approach." Doctoral thesis, Umeå universitet, Kemiska institutionen, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-111309.
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The WHO classification of brain tumors is based on histological features and the aggressiveness of the tumor is classified from grade I to IV, where grade IV is the most aggressive. Today, the correlation between prognosis and tumor grade is the most important component in tumor classification. High grade gliomas, glioblastomas, are associated with poor prognosis and a median survival of 14 months including all available treatments. Low grade meningiomas, usually benign grade I tumors, are in most cases cured by surgical resection. However despite their benign appearance grade I meningiomas can, without any histopathological signs, in some cases develop bone invasive growth and become lethal. Thus, it is necessary to improve conventional treatment modalities, develop new treatment strategies and improve the knowledge regarding the basic pathophysiology in the classification and treatment of brain tumors. In this thesis, both proteomics and metabolomics have been applied in the search for biomarkers or biomarker patterns in two different types of brain tumors, gliomas and meningiomas. Proteomic studies were carried out mainly by surface enhanced laser desorption ionization time of flight mass spectrometry (SELDI-TOF-MS). In one of the studies, isobaric tags for relative and absolute quantitation (iTRAQ) labeling in combination with high-performance liquid chromatography (HPLC) was used for protein detection and identification. For metabolomics, gas-chromatography time-of-flight mass spectrometry (GC-TOF-MS) has been the main platform used throughout this work for generation of robust global metabolite profiles in tissue, blood and cell cultures. To deal with the complexity of the generated data, and to be able to extract relevant biomarker patters or latent biomarkers, for interpretation, prediction and prognosis, bioinformatic strategies based on chemometrics were applied throughout the studies of the thesis. In summary, we detected differentiating protein profiles between invasive and non-invasive meningiomas, in both fibrous and meningothelial tumors. Furthermore, in a different study we discovered treatment induce protein pattern changes in a rat glioma model treated with an angiogenesis inhibitor. We identified a cluster of proteins linked to angiogenesis. One of those proteins, HSP90, was found elevated in relation to treatment in tumors, following ELISA validation. An interesting observation in a separate study was that it was possible to detect metabolite pattern changes in the serum metabolome, as an effect of treatment with radiotherapy, and that these pattern changes differed between different patients, highlighting a possibility for monitoring individual treatment response. In the fourth study of this work, we investigated tissue and serum from glioma patients that revealed differences in the metabolome between glioblastoma and oligodendroglioma, as well as between oligodendroglioma grade II and grade III. In addition, we discovered metabolite patterns associated to survival in both glioblastoma and oligodendroglioma. In our final work, we identified metabolite pattern differences between cell lines from a subgroup of glioblastomas lacking argininosuccinate synthetase (ASS1) expression, (ASS1 negative glioblastomas), making them auxotrophic for arginine, a metabolite required for tumor growth and proliferation, as compared to glioblastomas with normal ASS1 expression (ASS1 positive). From the identified metabolite pattern differences we could verify the hypothesized alterations in the arginine biosynthetic pathway. We also identified additional interesting metabolites that may provide clues for future diagnostics and treatments. Finally, we were able to verify the specific treatment effect of ASS1 negative cells by means of arginine deprivation on a metabolic level.
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Cavers, Debbie Grant. "Understanding the supportive care needs of glioma patients and their relatives : a qualitative longitudinal study." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/10630.
Full textAbstract:
Background: Malignant cerebral glioma is a rare cancer but has a devastating impact on patients and their families. In Scotland each year, around 450 people are diagnosed with glioma. Prognosis is generally poor and treatment is essentially palliative. There is a growing recognition that non-clinical aspects of care for both patients and their families need to be acknowledged and integrated into health care provision in line with a patient-focused ethos of care. Currently, there is relatively little research exploring the psychosocial issues and needs of this patient group. Aims: To give patients being investigated for malignant cerebral glioma and their families the opportunity to describe their shared experiences of their illness journey and voice their concerns and unmet needs. To examine how these experiences and needs change over time as the patient progresses through the illness journey. To ascertain the extent to which these needs are recognised and supported, taking into accounts professionals’ views and making suggestions for steps forward in improving patients’ psychosocial care. Methods: A total of 80 qualitative prospective longitudinal interviews (30 paired and 50 separate) were conducted with 26 people with a suspected or confirmed diagnosis of malignant cerebral glioma being treated at a regional hospital and 24 primary relative/informal carers. Patients and carers were interviewed at the following five times: leading up to diagnosis; following a formal diagnosis; around the end of initial treatment (radiotherapy); at a designated six-month follow-up stage; and bereavement interviews with carers. One-off interviews were carried out with 66 health professionals (19 case-linked GPs and 47 other health, health-related and social care professionals involved in patients' care). Interviews were recorded and transcribed verbatim and analysed using the constant comparative method from a grounded theory approach assisted by QSR NVivo Version 7. Findings: Distress, anxiety and shock were overwhelming reactions in the period leading up to a diagnosis of glioma, making it difficult for participants to make sense of their experience. Over time, participants employed a range of strategies in order to cope with their diagnosis. Social and emotional support from professionals and friends, family and other patients were vital in many cases but support often felt inadequate. The role of information and the manner in which it was communicated was closely linked to participants’ ability to cope. Information needs were variable but on the whole patients and carers did not feel well informed. Dealing with cognitive and physical symptoms of their illness and side effects of treatment inhibited patients’ ability to resume their everyday activities. The lives of relatives were also affected as they struggled to care for their loved ones. People with a diagnosis of glioma were faced with the possibility of death from an early point in their illness trajectory and awareness of this, coupled with ability to make sense of existential issues, varied across participants. Issues around support, communication, information and palliative care were considered to be important among health professionals involved in the care of people with a diagnosis of glioma but provision fell short. Conclusions: Concerns regarding information, communication and support reported elsewhere in the literature are enduring in glioma patients and their relatives. Reporting of unmet psychosocial and supportive care issues by patients and recognition by professionals of the need to improve these dimensions of care for people affected by glioma emphasises previous recommendations yet to be fully implemented into patient care.
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Lombardi, Giuseppe. "2-Hydroxyglutarate as a biomarker in glioma patients." Doctoral thesis, Università degli studi di Padova, 2014. http://hdl.handle.net/11577/3423791.
Full textAbstract:
Background: mutation of IDH1 gene is a prognostic factor and a diagnostic hallmark of gliomas. Mutant IDH1 enzyme can convert α-KG into 2-Hydroxyglutarate (2HG) and mutated gliomas have elevated amounts of intracellular 2HG. Since 2HG is a small molecule it seems possible that it could reach the systemic circulation and to be excreted by urine. And so, we analyzed 2HG concentration in plasma and urine in glioma patients to identify a surrogate biomarker of IDH1 gene mutation.
Materials and Methods: All patients had a prior histological confirmation of glioma, a recent brain MRI (within 2 weeks) showing the neoplastic lesions. The exclusion criteria were any chemotherapy performed within 28 days prior, other neoplastic and metabolic diseases. Plasma and urine samples were taken from all patients and 2HG concentrations determined by liquid chromatography tandem mass spectrometry; exon 4 of IDH1 genes were analyzed by Sanger sequencing; differences in metabolite concentrations between mutant and wild-type IDH1 patients were examined with the Mann-Whitney U test for non-parametric data; Student’s t-test was used to compare parametric data. ROC curve was used to evaluate the cut off value of the 2HG biomarker.
Results: 84 patients were enrolled: 38 with IDH1 mutated and 46 IDH1 wild-type.
All the mutations were R132H. Among patients with mutant IDH1 we had 21 highgrade gliomas (HGG) and 17 low-grade gliomas (LGG); among patients with IDH wild-type we had 35 HGG and 11 LGG.. In all patients we analyzed the mean 2HG concentration in plasma (P_2HG), in urine (U_2HG) and the ratio between P_2HG and U_2HG (R_2HG).
We found an important significant difference in R_2HG between glioma patients with and without IDH1 mutation (22.2 versus 15.6, respectively, p<0.0001). The optimal cut-off value of R_2HG to identify glioma patients with and without IDH mutation was 19 (sensitivity 63%, specificity 76%, accuracy 70%); in only PTS with HGG the optimal cut-off value was 20 (sensitivity 76%, specificity 89%, accuracy 84%, positive predictive value 80%, negative predictive value 86%). No associations between the grade or size of tumor and R_2HG were found. In 7 patients with highgrade gliomas we found a correlation between R_2HG value and response to treatment.
Conclusions: analyzing R_2HG derived from individual plasma and urine 2HG levels is possible discriminate glioma patients with and without IDH mutation, in particular in high grade gliomas. Moreover, a larger samples need to be analyzed to investigate this method in patients follow-up for recurrence detection and to monitor treatment efficacy.<br>Background: la mutazione del gene IDH1 rappresenta un importante fattore prognostico e diagnostico per i tumori gliali. L’enzima IDH1 avente la mutazione ha la capacità di convertire α-KG in 2-Idrossiglutarato (2HG) e i gliomi mutati hanno una elevata concentrazione di 2HG all’interno delle cellule tumorali. Poichè 2HG è una piccola molecola, tale metabolita potrebbe raggiungere la circolazione sistemica ed essere escreta con le urine. Per tale ragione, nel nostro studio abbiamo analizzato la concentrazione di 2HG nel plasma e nelle urine nei pazienti con glioma per identificare un biomarcatore surrogato della presenza della mutazione IDH1.
Materiali e Metodi: per l’arruolamento, tutti i pazienti dovevano avere avuto una precedente conferma istologica di glioma, una recente risonanza magnetica cerebrale (entro 2 settimane) mostrante la lesione tumorale. Qualsiasi chemioterapia eseguita nei 28 giorni precedenti l’analisi del metabolita, la presenza di altre malattie tumorali e malattie metaboliche escludevano l’arruolamento del paziente. Campioni plasmatici e urinari sono stati ottenuti da tutti i pazienti e le concentrazioni di 2HG ottenute mediante cromatografia liquida-spettrometria di massa; il test di Mann-Whitney è stato usato per calcolare le differenze di concentrazione dei metaboliti tra pazienti con IDH1 mutato e non-mutato, per dati non parametrici; il test di Student per comparare dati parametrici. La curva ROC è stata usata per calcolare il valore di cut-off del 2HG come biomarcatore.
Risultati: sono stati arruolati 84 pazienti: 38 con IDH1 mutato e 46 con IDH1 wildtype.
Tutte le mutazioni sono state R132H. Tra i pazienti con mutazione IDH1 abbiamo avuto 21 gliomi ad alto grado (HGG) e 17 gliomi a basso grado (LGG). Tra i pazienti con IDH1 wild-type abbiamo avuto 35 pazienti con HGG e 11 con LGG. In tutti i pazienti abbiamo analizzato la concentrazione media di 2HG nel plasma (P_2HG), nell’urina (U_2HG) e il rapporto tra la concentrazione plasmatica e urinaria (R_2HG). E’ emersa una importante differenza statisticamente significativa per l’R_2HG tra pazienti con e senza mutazione dell’IDH1 (22.2 verso 15.6, p<0.0001). Il cut-off ottimale di R_2HG per identificare lo stato mutazionale di IDH1 nei pazienti con glioma è risultato essere 19 (sensibilità 63%, specificità 76%, accuratezza 70%); nei soli pazienti con glioma ad alto grado il cut-off ottimale è risultato essere 20 (sensibilità 76%, specificità 89%, accuratezza 84%, valore predittivo positivo 80%, valore predittivo negativo 86%). Non è emersa nessuna associazione tra il grado o la dimensione del tumore con il valore di R_2HG. In 7 pazienti con glioma ad alto grado analizzati abbiamo, inoltre, trovato una correlazione tra il valore di R_2HG e la risposta al trattamento.
Conclusioni: attraverso l’analisi di R_2HG, derivato dalla concentrazione plasmatica e urinaria di 2HG, è possibile discriminare gliomi con e senza mutazione IDH1, soprattutto in gliomi di alto grado. Occorrerà analizzare un campione più grande di pazienti con glioma per investigare tale metodica anche nel follow up allo scopo di individuare precocemente la recidiva di malattia e per monitorare l’efficacia del trattamento.
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Konnully, Augustus Meera Bessy. "Characterization of cellular heterogeneity in Diffuse Low Grade Glioma." Thesis, Montpellier, 2020. http://www.theses.fr/2020MONTT038.
Full textAbstract:
Les gliomes diffus de bas grade (DLGG) sont des tumeurs gliales de grade II qui affectent principalement les jeunes adultes. Elles sont caractérisées par une croissance lente et une activité mitotique réduite. Cependant, ces tumeurs diffusent et envahissent le cerveau sain via les vaisseaux sanguins et les fibres nerveuses. Après plusieurs années de croissance lente, ces tumeurs peuvent évoluer vers des glioblastomes, des tumeurs cérébrales très agressives dont la survie médiane moyenne est alors de 12 à 15 mois après le diagnostic. La caractérisation cellulaire des DLGG est encore limitée ce qui nuit à la recherche d’un traitement à un stade précoce. Dans ma thèse de doctorat, je me suis focalisée sur la caractérisation de 'hétérogénéité cellulaire des DLGG mutés pour IDH1. En effectuant une analyse d'immunofluorescence sur des astrocytomes et oligodendrogliomes de grade II, j'ai identifié deux sous-populations cellulaires largement non chevauchantes et exprimant respectivement les facteurs de transcription SOX9 et OLIG1. Ces cellules s’apparentent à des cellules de type astrocytaire et oligodendrocytaire et expriment des marqueurs moléculaires distincts. Les cellules SOX9 expriment APOE, KCNN3, CRYAB et ID4, tandis que les cellules OLIG1 expriment préfentiellement PDGFRA, SOX8, MASH1 et SOX4. Par ailleurs, j’ai montré que les cellules SOX9 présentent une activation particulière des voies de signalisation, notamment Notch, BMP et leurs cibles en aval. Pour étudier le rôle de la voie de signalisation Notch dans la formation de ces 2 sous-populations tumorales, j'ai purifié par tri magnétique les cellules tumorales à partir d'échantillons de gliomes fraîchement réséqués et j'ai surexprimé le domaine intracellulaire Notch (NICD), une forme active de Notch. J’ai ainsi montré que cette activation augmentait l’expression des marqueurs cellulaires associés aux cellules SOX9+ et une baisse de ceux associés aux cellules OLIG1+. J'ai ensuite étendu ces analyses à une lignée cellulaire anaplasique dérivée d'un patient et mutée pour IDH1. Ces résultats indiquent un rôle clé de la signalisation Notch dans la régulation de la plasticité des cellules tumorales. Des expériences similaires pour étudier l'activation de la signalisation BMP (bone morphogenetic protein) n'ont pas montré d'effet notable sur la plasticité. Néanmoins, le traitement des cellules par des membres de la famille BMP a fortement augmenté l’expression de CRYAB, un marqueur associé à SOX9, et a diminué l’expression de OLIG1 et OLIG2. En conclusion, j'ai identifié deux sous-populations tumorales non chevauchantes dans des gliomes diffus de bas grade et j'ai démontré le rôle déterminant de la voie de signalisation Notch dans leur formation. Ces résultats permettront de mieux comprendre l'hétérogénéité tumorale dans les DLGG et de concevoir de nouvelles stratégies thérapeutiques contre ces tumeurs<br>Diffuse Low-Grade Gliomas (DLGG) are WHO grade II glial tumors affecting younger adults. They are characterized as silent, slow growing tumors with fewer mitotic activities. However, they diffuse and invade the healthy brain via blood vessels and nerve fibers. These, over a period of years develop to malignant Glioblastoma, aggressive brain tumors where patients have an average medial survival of 12-15 months after diagnosis. Ill-defined phenotypic and cellular diversity of DLGG poses serious limitation to treatment and prevention at the early stage.In my PhD thesis, I aimed to address this limitation by characterizing the cellular heterogeneity in IDH1-mutated DLGG. By performing immunofluorescence analysis on grade II astrocytoma and oligodendroglioma, I have identified two largely non-overlapping cellular subpopulations expressing SOX9 and OLIG1 transcription factors, which represent astrocyte-like and oligodendrocyte-like cells, respectively. Upon further investigation, I have shown that these subpopulations express distinct molecular markers. Sox9 cells are associated with APOE, KCNN3, CRYAB and ID4, while Olig1 cells showed strong correlation with the expression of PDGFRA, SOX8, MASH1, and SOX4. In addition, the sox9 cells show a particular activation of signaling pathways including Notch, BMP and their downstream targets.To ascertain the role of Notch signaling in regulating the formation of these tumoral subpopulations, I used magnetic sorting of tumor cells from freshly resected glioma samples and overexpressed Notch Intracellular Domain (NICD), an active form of Notch. Increased Notch activation resulted in an upregulation of Sox9- and downregulation of Olig1-associated cell markers. I have then extended these analyses on one anaplastic IDH1 mutated patient derived cell line which reproduced similar gene expression profile confirming the robustness of the role of Notch signaling in regulating the plasticity of the cells. Parallel experiments performed by activation of Bone Morphogenetic Protein (BMP) signaling on IDH1 mutated cell line did not show a prominent effect on the plasticity. Nevertheless, BMP signal activation highly upregulated CRYAB, a SOX9 related marker and downregulated OLIG1 and OLIG2.In conclusion, I have identified two non-overlapping tumor subpopulations in diffuse low-grade gliomas and demonstrated the deterministic role of Notch signaling pathway in their formation. I believe that these findings would aid in better understanding tumoral heterogeneity in DLGG and be extended in designing new therapeutic strategies against these tumors
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Geremia, Ezequiel. "Spatial random forests for brain lesions segmentation in MRIs and model-based tumor cell extrapolation." Phd thesis, Université Nice Sophia Antipolis, 2013. http://tel.archives-ouvertes.fr/tel-00838795.
Full textAbstract:
The large size of the datasets produced by medical imaging protocols contributes to the success of supervised discriminative methods for semantic labelling of images. Our study makes use of a general and efficient emerging framework, discriminative random forests, for the detection of brain lesions in multi-modal magnetic resonance images (MRIs). The contribution is three-fold. First, we focus on segmentation of brain lesions which is an essential task to diagnosis, prognosis and therapy planning. A context-aware random forest is designed for the automatic multi-class segmentation of MS lesions, low grade and high grade gliomas in MR images. It uses multi-channel MRIs, prior knowledge on tissue classes, symmetrical and long-range spatial context to discriminate lesions from background. Then, we investigate the promising perspective of estimating the brain tumor cell density from MRIs. A generative-discriminative framework is presented to learn the latent and clinically unavailable tumor cell density from model-based estimations associated with synthetic MRIs. The generative model is a validated and publicly available biophysiological tumor growth simulator. The discriminative model builds on multi-variate regression random forests to estimate the voxel-wise distribution of tumor cell density from input MRIs. Finally, we present the "Spatially Adaptive Random Forests" which merge the benefits of multi-scale and random forest methods and apply it to previously cited classification and regression settings. Quantitative evaluation of the proposed methods are carried out on publicly available labeled datasets and demonstrate state of the art performance.
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Soldatelli, Jéssica Silveira. "Efeitos da combinação de temozolomida e ditelureto de difenila em linhagens celulares de glioblastoma." reponame:Repositório Institucional da UCS, 2018. https://repositorio.ucs.br/11338/4064.
Full textAbstract:
Os gliomas representam mais de 70% dos tumores cerebrais primários. Os glioblastomas multiformes são gliomas malignos caracterizados por baixa incidência, mas altas taxas de mortalidade. Apesar da responsividade inicial ao tratamento padrão realizado com o quimioterápico alquilante temozolomida (TMZ), poucos foram os avanços para o prognóstico dos pacientes nos últimos 10 anos. Isso deve-se ao fato desses tumores serem raramente passíveis de ressecção cirúrgica e apresentarem alta taxa de recorrência. Além disso, a eficácia de seu tratamento encontra barreiras como efeitos colaterais indesejáveis e resistência quimioterápica. Nesse cenário, a descoberta de novas substâncias que possam atuar com efeito aditivo ou sinérgico e aumentem a sensibilização de células tumorais ao tratamento, torna-se uma estratégia terapêutica no campo da oncologia. O ditelureto de difenila (DTDF) é um composto orgânico contendo telúrio que apresenta interessantes efeitos biológicos in vitro, como antioxidante, quimioprotetivo, citotóxico e antitumoral. Sendo assim, o objetivo deste estudo foi avaliar os efeitos do DTDF e do quimioterápico TMZ, em regimes isolados e em associação. Para tal foram investigados seus efeitos citotóxicos, após exposição aguda e crônica, em culturas celulares de glioma não-resistente (M059J) e resistente à TMZ (GBM). No ensaio de viabilidade celular a TMZ apresentou citotoxicidade para as linhagens celulares testadas, com valor de IC50 maior na linhagem resistente do que quando comparado à linhagem não-resistente. Este dado foi confirmado pelo teste de duplicação cumulativa de população e, também, pela coloração com laranja de acridina, após o tratamento de 120 h, por observar-se um aumento na frequência de células positivas para a formação de organelas vesiculares ácidas em ambas as linhagens, sendo predominantemente em células GBM. Além disso, foi observado que o tratamento associando DTDF e a TMZ apresentou uma maior citotoxicidade quando comparado aos tratamentos isolados, após 120 h de tratamento. Portanto, o DTDF sensibilizou as células ao tratamento com TMZ. Essa sensibilização ocorreu em níveis aproximados para ambas as linhagens, sendo os efeitos do DTDF independentes do perfil de resistência à TMZ. Em conjunto, os dados desse trabalho sugerem o uso do DTDF em associação à TMZ como uma estratégia para reduzir as doses de TMZ empregadas na clínica e diminuir efeitos colaterais aos pacientes em tratamento de glioma<br>Gliomas represent more than 70% of primary brain tumors. Malignant gliomas are characterized by low incidence, but high mortality rates. Despite the initial responsiveness to the standard treatment with the chemotherapeutic alkylating temozolomide (TMZ), few advances have been made in the prognosis of patients in the last 10 years. This is due to the fact that these tumors are rarely amenable to surgical resection and have a high rate of recurrence. Moreover, the effectiveness of this treatment encounters barriers such as undesirable side effects and chemotherapeutic resistance. In this scenario, the discovery of new substances that may act with additive or synergistic effect and increase the sensitization of tumor cells to the treatment becomes a therapeutic strategy in the field of oncology. Diphenyl ditelluride (DPDT) is a derivative of tellurium used in various reactions of organic synthesis and has interesting in vitro biological effects, as antioxidant, chemoprotective, cytotoxic and antitumor agent. Therefore this work aimed to evaluate the cytotoxic effects of this organotellurium compound and the chemotherapeutic, TMZ, in isolated and in association regimens, after acute and chronic exposure, of non-resistant (M059J) and TMZ- resistant (GBM) glioma cells. Through the cell viability assay, it was shown that TMZ is cytotoxic for both cell lines tested, showing a higher IC50 value in the resistant line when compared to the other line. This data was confirmed by the cumulative population doubling test. In addition, by the acridine orange staining, it was verified that autophagy might favor the chemoresistance, although not being the main resistance mechanism in the lines tested. It was observed that DPDT clearly has a dose-dependent cytotoxic effect on the M059J and GBM cell lines, in a lower concentration range than that used with TMZ. DPDT sensitized the cells to TMZ treatment as evidenced by the decline in cell viability. It is important to point out that this sensitization occurred in low and approximate IC50 values after both 24 h and 120 h of treatment, being the effects of the DPDT independent of the resistance profile to TMZ. Taken together, data from this work suggest the use of DPDT in association with TMZ as an interesting strategy to reduce the doses of TMZ used in the clinic and to reduce side effects to patients under treatment of glioma.
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Legge, Dianne M. "Accommodating life disruption: An interpretive exploration of living with a low-grade glioma." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/126757/1/Dianne_Legge_Thesis.pdf.
Full textAbstract:
This research focuses on understanding how people living with a low-grade glioma diagnosis accommodate significant disruption to their lives and future plans. Exploring the meaning of social interactions, processes and language exposed the ambiguous clinical context and the necessity for people to reappraise values and connections, and renegotiate their identity to live with this illness. Findings suggest the need for greater attention to the survivorship needs of people with low-grade glioma to facilitate connection with identity and engage in productive community life. The importance of continued improvement in health professionals' communication with patients is reinforced.
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Andrade, Fernanda Gonçalves de. "Estudo das alterações na expressão gênica dos ependimomas." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/5/5138/tde-01092014-154140/.
Full textAbstract:
Ependimomas são tumores gliais raros. Podem ser encontrados em qualquer localização do sistema nervoso central e, apesar de histologia similar, parecem apresentar alterações genômicas distintas. As variáveis clínicas são intercorrelacionadas e, geralmente, incapazes de predizer o curso da doença. O objetivo do presente estudo foi analisar a expressão aumentada de genes e proteínas em ependimomas e correlacionar com dados clínicos dos pacientes. Foram estudados casos de pacientes com ependimoma submetidos à ressecção cirúrgica no Hospital das Clínicas, Universidade de São Paulo, no período entre 1996 e 2011 (33 amostras de tecido congelado para análise de expressão gênica por PCR quantitativo em tempo real e 149 amostras com tecido incluído em parafina, correspondentes a 121 casos devido a recidivas, para análise de proteína por imuno-histoquímica de tissue microarrays). As reações de imuno-histoquímica foram analisadas semiquantitativamente e graduadas com um índice de marcação calculado pelo produto da porcentagem de núcleos marcados pela intensidade de marcação. Oitenta e um casos eram adultos (média de 27,2 anos). Havia 60 casos intracranianos e 61 intramedulares, dos quais 10 eram mixopapilares, 92 grau II e 19 grau III. Ressecção completa foi possível em 62% dos casos e recidiva foi confirmada em 41,1%. Observou-se menor tempo para recidiva em crianças e tumores intracranianos, supratentoriais (p < 0,001 em ambos), histologia anaplásica e ressecções incompletas (p < 0,05 em ambos). Os seguintes genes foram selecionados em dados públicos de SAGE e literatura: ARMC3, CCND1, CHST5, DNALI1, FGFRL1, GNA13, IGF2, MSX1, NOTCH1 e RSPH3. ARMC3, RSHL3, CHST5 e DNALI1 apresentaram maiores níveis de expressão em ependimomas intramedulares (p < 0,05), e FGFRL1, NOTCH1 e CCND1 nos casos supratentoriais (p < 0,01). IGF2 apresentou maiores níveis de expressão em crianças e CHST5 em adultos (p < 0,05 em ambos). Foram observados maiores níveis de expressão de FGFRL1 (p < 0,05), CCND1 e IGF2 (p < 0,01 em ambos) em casos com histologia anaplásica. Nenhum dos genes analisados apresentou impacto no tempo livre de progressão ou na sobrevida. A expressão da proteína codificada por CCND1, ciclina D1, também foi avaliada por imuno-histoquímica, por ser uma proteína com expressão aumentada em diversos tipos de neoplasias e não ter ainda um valor prognóstico bem estabelecido em ependimomas. Houve correlação entre expressão de ciclina D1 a nível de mRNA e da proteína (p < 0,0001). As correlações entre ciclina D1 e histologia anaplásica e localização supratentorial foram confirmadas pela análise proteica (p < 0,0001 em ambos). Adicionalmente, foi também observada maior expressão de ciclina D1 em pacientes mais jovens (p < 0,01). A maior expressão de ciclina D1 em tumores com localização supratentorial foi independente do grau histológico e da idade do paciente. Recidiva foi mais frequente em casos com maiores níveis de expressão de ciclina D1 (p < 0,05), embora uma maior correlação com tempo livre de progressão foi observada apenas em casos com ressecção completa (p < 0,001). Os ependimomas apresentaram expressão gênica diferencial de acordo com idade, localização do tumor e grau histológico nesse estudo. A determinação dos níveis da expressão de ciclina D1 pode ser útil para guiar o seguimento e tratamento dos casos supratentoriais com ressecções completas<br>Ependymomas are rare glial cell-derived tumors. They can be found in any central nervous system localization and despite the histological similarity, they seem to display distinct genomic abnormalities. Clinical variables are intercorrelated and they are usually unable to predict the disease course. We aimed to analyze increased gene and protein expression in ependymomas and to correlate with patients\' clinical data. We studied patients with ependymoma submitted to surgical resections at Hospital das Clinicas, University of São Paulo, from 1996 to 2011 (33 fresh-frozen samples for gene expression analysis by quantitative real-time PCR and 149 formalin-fixed, paraffin-embedded samples, relative to 121 patients due to relapses, for protein analysis by tissue microarray immunohistochemistry). Immunohistochemical reactions were analyzed semi-quantitatively and scored with a labeling index (LI) calculated as the product of the percentage of the positively stained nuclei by the intensity of staining. Eighty-one cases were adults (mean 27.2 years). There were 60 intracranial and 61 spinal cases, of which 10 tumors were myxopapillary, 92 were grade II and 19 were grade III. Gross total resection was achieved in 62% of cases and relapse was confirmed in 41.4% of cases. We observed a shorther time to relapse in children and supratentorial intracranial tumor localization (p<0.001 for both), anaplastic histology and incomplete resections (p<0.05 for both). The following genes were selected based on public SAGE database and literature: ARMC3, CCND1, CHST5, DNALI1, FGFRL1, GNA13, IGF2, MSX1, NOTCH1 and RSPH3. ARMC3, RSHL3, CHST5 and DNALI1 presented higher expression levels in intramedullary ependymomas (p < 0.05) and FGFRL1, NOTCH1 and CCND1 in supratentorial cases (p < 0.01). IGF2 presented higher expression levels in pediatric cases and CHST5 in adults cases (p < 0.05 in both). Higher expression levels of FGFRLI1 (p < 0.05), CCND1 and IGF2 (p < 0.01 for both) were observed in anaplastic histology cases. None of the genes impacted in progression free survival or overall survival of patients. The expression of protein codified by CCND1, cyclin D1, was also evaluated by immunohistochemistry, because its overexpression has been related with several types of neoplasias and its prognostic value has not yet been fully established in ependymomas. There was a correlation of cyclin D1 expression at mRNA and protein levels (p < 0.0001). Correlations between cyclin D1 and anaplastic histology and supratentorial localization were confirmed by protein analyses (p < 0.0001 for both parameters). Additionally, high expression of cyclin D1 was observed in younger patients (p < 0.01). The higher cyclin D1 expression in supratentorial tumor localization was independent of histological grade and age of patient. Relapse was more frequent in cases with higher cyclin D1 expression levels (p < 0.05) although correlation with progression free survival was just observed in gross total resection cases (p < 0.001). Ependymomas presented differential gene expression according to age, tumor localization and histological grade in our study. Determination of cyclin D1 expression levels may be useful to guide follow-up and treatment in supratentorial cases with gross total resection
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Mullet, Emily. "Functional Consequences of Matrix Metalloproteinase-1 Over-Expression in Human Gliomas." VCU Scholars Compass, 2006. http://hdl.handle.net/10156/1437.
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Uyar, Ramazan [Verfasser], and Rainer [Akademischer Betreuer] Glaß. "Glioma-associated mesenchymal stem cells have profound effects on brain tumors / Ramazan Uyar ; Betreuer: Rainer Glaß." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2019. http://d-nb.info/1202011683/34.
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Sångberg, Dennis. "Automated Glioma Segmentation in MRI using Deep Convolutional Networks." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171046.
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Manual segmentation of brain tumours is a time consuming process, results often show high variability, and there is a call for automation in clinical practice. In this thesis the use of deep convolutional networks for automatic glioma segmentation in MRI is investigated. The implemented networks are evaluated on data used in the brain tumor segmentation challenge (BraTS). It is found that 3D convolutional networks generally outperform 2D convolutional networks, and that the best networks can produce segmentations that closely resemble human segmentations. Convolutional networks are also evaluated as feature extractors with linear SVM classifiers on top, and although the sensitivity is improved considerably, the segmentations are heavily oversegmented. The importance of the amount of data available is investigated as well by comparing results from networks trained on both 2013 and the greatly extended 2014 data set, but it is found that the method of producing ground-truth was also a contributing factor. The networks does not beat the previous high-scores on the BraTS data, but several simple improvement areas are identified to take the networks further.<br>Manuell segmentering av hjärntumörer är en tidskrävande process, segmenteringarna är ofta varierade mellan experter, och automatisk segmentering skulle vara användbart för kliniskt bruk. Den här rapporten undersöker användningen av deep convolutional networks (ConvNets) för automatisk segmentering av gliom i MR-bilder. De implementerade nätverken utvärderas med hjälp av data från brain tumor segmentation challenge (BraTS). Studien finner att 3D-nätverk har generellt bättre resultat än 2D-nätverk, och att de bästa nätverken har förmågan att ge segmenteringar som liknar mänskliga segmenteringar. ConvNets utvärderas också som feature extractors, med linjära SVM som klassificerare. Den här metoden ger segmenteringar med hög känslighet, men är också till hög grad översegmenterade. Vikten av att ha mer träningsdata undersöks också genom att träna på två olika stora dataset, men metoden för att få fram de riktiga segmenteringarna har troligen också stor påverkan på resultatet. Nätverken slår inte de tidigare rekorden på BraTS, men flera viktiga men enkla förbättringsområden är identifierade som potentiellt skulle förbättra resultaten.
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Singh, Anushree. "A clinicopathological and molecular genetic analysis of low-grade glioma in adults." Thesis, University of Wolverhampton, 2014. http://hdl.handle.net/2436/578733.
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The aim of the study was to identify molecular markers that can determine progression of low grade glioma. This was done using various approaches such as IDH1 and IDH2 mutation analysis, MGMT methylation analysis, copy number analysis using array comparative genomic hybridisation and identification of differentially expressed miRNAs using miRNA microarray analysis. IDH1 mutation was present at a frequency of 71% in low grade glioma and was identified as an independent marker for improved OS in a multivariate analysis, which confirms the previous findings in low grade glioma studies. IDH1 mutation was associated with MGMT promoter methylation when partially methylated tumours were grouped with methylated tumours. Grade II and grade III tumour comparison analysis revealed 14 novel significant miRNAs with differential expression. A miRNA signature was shown for histological subtypes, oligoastrocytoma and anaplastic oligoastrocytoma, following the miRNA expression analysis in grade II and grade III tumors based on histology. Oligoastrocytoma presented a more similar profile to oligodendroglioma, but anaplastic oligoastrocytoma was more similar to anaplastic astrocytoma. Five novel miRNAs were identified in grade III tumours, when comparing IDH1 mutant and IDH1 wild type tumours. Analysis of paired samples of primary/recurrent tumours revealed that additional genomic changes may promote tumour progression. For each of the pair, the two samples were genomically different and in each case, the reccurent tumours had more copy number aberrations than the corresponding primary tumours. Cell cultures derived from the tumour biopsies were not representative of the low grade glioma in vivo, which was evident from the differences identified in the miRNA expression and copy number changes in the paired samples. IDH1 mutation present in tumour biopsies was not maintained in their respective cell cultures. These findings give an insight into the molecular mechanisms involved in the tumourigenesis of low grade glioma and also tumour progression.
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Kao, Chen-Yu. "Developing a Minimally Invasive Sustained Release System for Glioma Therapy." Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19757.
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Malignant brain tumor is one of the most lethal forms of cancers. In the United States alone, approximately 20,500 new cases of primary malignant brain and central nervous system tumors are expected to be diagnosed in 2007 with 12,740 deaths estimated. Treatment of malignant brain tumor remains a major challenge despite recent advance in surgery and other adjuvant therapies, such as chemotherapy. The failure of potential effective chemotherapeutics for brain tumor treatment is usually not due to the lack of potency of the drug, but rather can be attributed to lack of therapeutic strategies capable of overcoming blood brain barrier for effective delivery of drug to the brain tumor. In this thesis, we developed a minimally invasive sustained release system for glioma therapy. The present study was initiated in an effort to incorporated Doxorubicin (DOX) loaded PLGA particle into an agarose gel, which can provide a continuous release of DOX locally to the tumor site. DOX, a toposiomearase II inhibitor, is not currently used clinically for brain tumor treatment because when delivered systemically it does not cross BBB. Our hydrogel particle system can overcome this shortcoming of DOX. The results from this study demonstrate that the DOX/PLGA particle gel system can maintain the bioactivity of DOX and sustained release DOX for at least 15 day in vitro. The result of in vivo study showed the DOX/PLGA particle gel treated group had significantly extend the medium survival of 9L glioma bearing rat from 21 days to 29 days. Therefore, the success experience of this local and sustained delivery device might benefit the development of future glioma therapy strategy.
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Ali, Dulfikar A. "The feasibility of exercise in low and high grade glioma patients during radiation with or without adjuvant chemotherapy." Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/233465/1/Dulfikar_Ali_Thesis.pdf.
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This research was a longitudinal mixed methods study that involved the delivery of an exercise intervention in brain cancer patients undergoing treatment. Three studies were conducted to examine post-surgical functioning, feasibility and safety, and a qualitative review of patients’ acceptability and experiences.
This research highlighted functional deficits after surgery, limiting independence. The delivery of an exercise intervention during treatment is both feasible and safe. Clinically important improvements in aerobic functioning, lower-body strength and mobility were observed after cancer treatment. Participating in the exercise intervention provided patients with respite from their cancer journey and promoted positive coping ability towards future outlook.
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Suwala, Abigail Kora [Verfasser]. "Targeted glioma stem cell depletion through pharmacological WNT inhibition as a novel therapy for malignant brain tumors / Abigail Kora Suwala." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2019. http://d-nb.info/1190884062/34.
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Lanser, Brittany. "Characterization of checkpoint adaptation in human fibroblastic glioma cells and an analysis of protein phosphatase inhibitors." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences, c2012, 2012. http://hdl.handle.net/10133/3390.
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This thesis reports that checkpoint adaptation occurs in human brain cancer cells. M059K cells, after treatment with camptothecin (CPT), recruited γ-histone H2AX, phosphorylated Chk1 and arrested in the G2 phase. Strikingly, cells escaped the checkpoint, became rounded and entered mitosis as measured by phospho-histone H3 signals. Lamin A/C immunofluorescence microscopy revealed that 48% of the cells that survived checkpoint adaptation contained micronuclei. These data suggest that brain cancer cells undergo checkpoint adaptation and may have an altered genome. This thesis also explored if phosphatases participate in checkpoint adaptation. Human colon cancer cells were treated with CPT and the PP2A inhibitor cantharidin. Following treatment the cells became rounded and 65% were positive for phospho-histone H3 signals indicating that cantharidin caused cells to be in mitosis following CPT treatment. These data suggest that PP2A might have a role in checkpoint adaptation, or participate in a pathway that bypasses checkpoint adaptation.<br>xi, 114 leaves : ill. (some col.) ; 29 cm
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Pincerato, Rita de Cassia Maciel. "Classificação multiparamétrica dos tumores gliais por RM." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/5/5151/tde-01022011-172343/.
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INTRODUÇÃO: A referência padrão para determinação do grau tumoral é a avaliação histopatológica. Entretanto, algumas limitações estão associadas com a correta graduação histopatológica dos gliomas: (a) erro inerente da amostra associada a biópsia estereotáxica, sendo que a porção mais maligna do tumor pode não estar incluída na amostra obtida; (b) dificuldade em obter uma gama suficiente de amostras se o tumor for inacessível ao cirurgião;(c) dinâmica própria dos tumores do sistema nervoso central, com diferenciação freqüente em graus de maior malignidade; (d) variabilidade entre patologistas; (e) inabilidade para avaliação de tecido tumoral residual após cirurgia redutora. Embora a ressonância magnética (RM) convencional seja a técnica de maior utilidade no diagnóstico e avaliação de tumores cerebrais, de forma isolada não possui acurácia em predizer o grau tumoral. Técnicas avançadas de RM, tais como caracterização de alterações metabólicas na espectroscopia de prótons (ERM), valores de volume sanguíneo cerebral relativo (VSCr) obtido com a perfusão por RM e imagem de difusão com o cálculo do coeficiente de difusão aparente (CDA), têm sido avaliadas como ferramentas diagnósticas na graduação prospectiva dos gliomas cerebrais. OBJETIVOS: Determinar quais são os parâmetros derivados da perfusão, difusão e espectroscopia que auxiliam a graduação tumoral. Determinar a sensibilidade, especificidade, valor preditivo positivo (VPP) e valor preditivo negativo (VPN) de cada método. Determinar se há alguma correlação entre os parâmetros utilizados na determinação do grau de malignidade tumoral. Determinar se a combinação destas técnicas aumenta a efetividade diagnóstica para graduação tumoral. MÉTODOS: 56 pacientes com tumores de origem glial, sendo 37 glioblastomas multiforme, 2 astrocitoma anaplásico, 1 oligoastrocitoma anaplásico, 3 oligoastrocitomas grau II, 9 astrocitomas grau II e 4 astrocitomas pilocíticos, foram submetidos a RM convencional, difusão, perfusão e ERM em aparelho 1,5 T (GE-Horizon LX9.1). O estudo da difusão foi realizado com sequência SE-EPI com tempo de repetição (TR)/tempo de eco (TE) = 8000/110,8ms. A perfusão foi adquirida com sequência GRE-EPI com TR/TE = 2000/34,7ms. Para o estudo de ERM utilizamos sequência multivoxel com TR/TE=1500/135ms. RESULTADOS: Diferenças significativas foram encontradas entre gliomas de baixo grau (BG) e alto grau (AG), com maiores valores de VSCr, Lip e Lip/Cr nos tumores de AG e maior valor de Cr nos tumores de BG. Tumores de AG apresentaram valores menores de CDA do que os de BG, porém sem diferença significativa. Correlação inversa foi observada entre valores de VSCr e CDA. O melhor parâmetro isolado para graduação tumoral foi o valor do VSCr. A combinação de VSCr e Cr, e VSCr e Lip, mostrou aumento da sensibilidade e especificidade na graduação dos gliomas. CONCLUSÕES: As alterações metabólicas utilizando a razão Lip/Cr, e os valores de Lip e Cr, assim como os valores de VSCr foram úteis na graduação tumoral. O melhor parâmetro para graduação tumoral foi o valor de VSCr. A combinação do VSCr e Cr, e VSCr e Lip aumenta a sensibilidade e especificidade na determinação da graduação dos gliomas<br>INTRODUCTION: The current reference standard for determining glioma grade is histopathologic assessment. However some limitations are associated with correct histopathologic grading of gliomas: (a) inherent sampling error associated with stereotactic biopsy and the risk of missing the most malignant portion of the tumor in the sampling; (b) difficulty in obtaining a representative range of samples if the tumor is inaccessible to the surgeon; (c) the dynamic nature of central nervous system tumors, with frequent dedifferentiation into more malignant grades; (d) interpathogist variability and (e) inability to evaluate residual tumor tissue after reductive surgery. Although MR imaging is the most useful radiologic technique in the diagnosis and evaluation of common brain tumors, it is not accurate enough in predicting tumor grade. Advanced MR imaging techniques such as characterization of metabolic changes in MR spectroscopy (MRS), relative cerebral blood volume (rCBV) measurements derived from perfusion MR imaging, and diffusion-weighted MR imaging with calculation of apparent diffusion coefficient (ADC), have been evaluated as diagnostic tool in prospective grading of cerebral gliomas. OBJECTIVES: To determine the usefulness of perfusion, diffusion, and spectroscopy values for glioma grading. To determine sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), of each method. To determine if there is any correlation between parameters used in glioma grading. To determine whether the combination of these techniques can improve the diagnostic effectiveness of glioma grading. METHODS: 56 patients with glial tumors: 37 glioblastoma multiforme, 2 anaplastic astrocytoma, 1 anaplastic oligoastrocytoma, 3 oligoastrocytomas grade II, 9 astrocytomas grade II and 4 pylocitic astrocytomas. Patients underwent conventional MR, diffusion, perfusion and MRS, performed with a 1.5-T unit (GE-Horizon LX9.1). The diffusion-weighted images were acquired by using a SE-EPI imaging sequence with repetition time (TR)/echo time (TE) = 8000/110.8ms. Perfusion-weighted imaging were acquired by using GRE-EPI with TR/TE = 2000/34.7ms. Multivoxel MRS imaging were acquired by using TR/TE=1500/135ms. RESULTS: Significant differences were noted between low-grade (LG) and high-grade (HG) gliomas with higher values of rCBV, Lip, Lip/Cr in HG, and higher values of Cr in LG. HG tumors had lower ADC values than LG, but with no statistical significant difference. An inverse relationship was observed between rCBV and ADC values. The best performing single parameter for glioma grading was rCBV value. Combination of rCBV and Cr, and rCBV and Lip, showed improvement in sensitivity and specificity in grading of gliomas. CONCLUSIONS: Metabolic changes using Lip/Cr ratio and Lip and Cr, and rCBV values were useful in tumor grading. The best parameter for glioma grading was rCBV value. The combination of rCBV and Cr, and rCBV and Lip increased the sensitivity and specificity in determining glioma grade
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DONISELLI, FABIO MARTINO. "NEW ADVANCES IN QUANTITATIVE RADIOLOGY: RADIOMICS IN NEURORADIOLOGY APPLIED TO PRIMARY BRAIN TUMORS USING A MACHINE LEARNING APPROACH." Doctoral thesis, Università degli Studi di Milano, 2022. http://hdl.handle.net/2434/932853.
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Arterial spin labelling (ASL) radiomics analysis to predict IDH mutation and MGMT methylation status in gliomas
Fabio M. Doniselli1,2, Riccardo Pascuzzo1, Eleonora Bruno3, Domenico Aquino1, Mattia Verri, Alberto Redolfi, Valeria Cuccarini1, Marco Moscatelli1,2, Maria Grazia Bruzzone1, Luca Maria Sconfienza2,4
Abstract
Objectives: To evaluate the strength and ability of radiomics features extracted from multiple tumor subregions on MR brain images to predict MGMT promoter (MGMT) methylation status and isocitrate dehydrogenase (IDH) mutation in glioma patients through a multiparametric MRI-based radiomics model, using arterial-spin labelling (ASL) perfusion imaging.
Methods: Retrospective single-institution study in a cohort of 52 glioma patients. Radiomics-based models with a minimal set of relevant features and clinical parameters were built for MGMT methylation and IDH-mutation prediction from a training cohort (31 patients) and tested on an validation cohort (13 patients).
Results: Feature selection methods (Boruta, RFE and LR-EL) identified age and 3 radiomics features for MGMT prediction and 3 features for IDH prediction. For IDH prediction, SVM classifier achieved average 96.8% accuracy and 0.929 AUC during the training phase, and 84.6% accuracy and 0.60 AUC on the test set. For MGMT methylation prediction, SVM classifier achieved average 67.7% accuracy and 0.765 AUC during the training phase, and 38.5% accuracy and 0.429 AUC on the test set.
Conclusions: The classification model based on both demographic (age) and radiomic ASL perfusion characteristics had the best performance in predicting the IDH mutational status of gliomas. This result suggests that the proposed method has promising efficacy in predicting IDH mutational status. We have not obtained a sufficient result trying to correlate radiomics with the MGMT mutational pattern.<br>Assessment of quality and classification performances of MRI-based radiomics studies on MGMT methylation in gliomas: a systematic review
Fabio M. Doniselli1,2*, Riccardo Pascuzzo1*, Massimiliano Agrò3, Domenico Aquino1, Federica Mazzi1, Francesco Padelli1, Marco Moscatelli1, Maria Grazia Bruzzone1, Luca M. Sconfienza2,4
Objectives
To evaluate the quality of MRI-based radiomics studies predicting the O6-methylguanine-DNA methyltransferase (MGMT) methylation status in gliomas, using radiomics quality score (RQS) and Image Biomarkers Standardization Initiative (IBSI) guidelines, and examine their classification performance.
Methods
PubMed Medline and EMBASE were searched to identify MRI-based radiomics studies on MGMT methylation in gliomas until January 31, 2022. Included studies were scored according to RQS (16 components) and IBSI (six items) scales by two raters.
Results
We included 20 out of 62 identified studies. The median RQS total score was 32% of the maximum (11.5 out of 36), ranging between 8% and 44%. Eleven studies performed external validation; only three studies performed decision curve analysis to report potential clinical utility. All studies reported area under the curve (AUC) or accuracy, and 14 computed these statistics using resampling methods (e.g., cross-validation). No study performed phantom study, cost-effectiveness analysis, and prospective validation. Regarding IBSI items, 14 studies (70%) performed signal intensity normalization, while few performed N4 bias-field correction (4, 20%) and skull stripping (3, 15%). Good classification performance (AUC>0.75) was obtained by 11 (55%) studies, but only four of them performed external validation (on sets with 20-60 patients). On the contrary, seven out of the nine studies with lower classification results performed external validation (on sets with 27-126 patients).
Conclusions
Adherence to RQS and IBSI guidelines was generally low. MGMT methylation status appears to be correlated with radiomic features, but with great heterogeneity of results. To confirm this trend, strict implementation of RQS and IBSI criteria is needed.<br>Radiomics for MGMT methylation detection in GBM using conventional pre-operative MRI
Fabio M. Doniselli1,2, Riccardo Pascuzzo1, Massimiliano Agrò3, Domenico Aquino1, Elena Anghileri, Bianca Pollo, Valeria Cuccarini1, Marco Moscatelli1, Francesco DiMeco, Maria Grazia Bruzzone1, Luca M. Sconfienza2,4
Abstract
Objectives: To evaluate the strength and ability of radiomics features extracted from multiple tumor subregions on MR brain images to predict MGMT promoter (MGMT) methylation status in GBM patients through a multiparametric MRI-based radiomics model.
Methods: Retrospective single-institution study in a cohort of 277 GBM patients. Radiomics-based models with a minimal set of relevant features and clinical parameters were built for MGMT methylation prediction from a training cohort (196 patients) and tested on an validation cohort (81 patients). Radiomic Quality Score (RQS) was equal to 15.
Results: Feature selection methods (Boruta, RFE and LR-EL) identified age and 218 radiomics features. SVM classifier achieved average 73.6% (standard deviation: 6.5%) accuracy and 0.836 (0.054) AUC during the training phase, and 59.3% (95% confidence interval: 47.8%-70.0%) accuracy and 0.553 (0.412-0.686) AUC on the test set.
Conclusions: We agree on the probable presence of subtle association between imaging characteristics and MGMT methylation status. However, further verification on the strength of this association is needed, as the low diagnostic performance in the validation cohort is still not sufficiently robust to allow clinically meaningful predictions.
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Leidgens, Verena Jeannine [Verfasser], and Peter [Akademischer Betreuer] Hau. "In situ and in vitro profiling of brain tumour initiating cells of high-grade gliomas / Verena Jeannine Leidgens. Betreuer: Peter Hau." Regensburg : Universitätsbibliothek Regensburg, 2016. http://d-nb.info/1100276777/34.
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Gualtieri, Marco. "In vivo analysis and manipulation of an invasive brain tumour." Electronic Thesis or Diss., Sorbonne université, 2022. http://www.theses.fr/2022SORUS388.
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Les tumeurs cérébrales primaires sont extrêmement agressives, et souvent incurables. Des cellules partageant de nombreuses caractéristiques des cellules souches neurales (CSNs) ont été identifiées dans plusieurs tumeurs cérébrales primaires. Celles-ci sont appelées cellules souches cancéreuses (CSCs) et présentent un potentiel d'autorenouvellement avec une prolifération illimitée. Les tumeurs dépendent fortement de leur microenvironnement cellulaire, qui résulte en parti du remodelage de populations préexistantes, telles que les cellules gliales et les vaisseaux sanguins (la barrière hémato-encéphalique). Dans ce projet, le système nerveux central de la drosophile est utilisé comme modèle in vivo afin de suivre les tumeurs cérébrales tout au long de la vie de l’hôte. Les CSNs de la drosophile représentent un modèle de cellules souches bien caractérisé à partir duquel des tumeurs peuvent être générées au cours du développement de l’hôte, puis survivre et proliférer largement à l’âge adulte. Dans ce système, je peux distinguer différentes populations de cellules dans la niche et explorer leur comportement par rapport aux CSC pendant la croissance tumorale. Je me suis particulièrement intéressé aux mécanismes d'interaction cellulaire qui se produisent dans les cellules gliales à l'interface avec les tumeurs. Mes résultats montrent qu'une sous-population de cellules gliales (les cellules gliales du cortex) subit une apoptose lors de la croissance tumorale, un mécanisme qui semble favoriser la propagation de la tumeur. Lorsque la mort des cellules gliales du cortex est stoppée, la croissance tumorale est réduite, ce qui suggère que la tumeur a, en partie, besoin de la mort des cellules gliales afin de se développer. En retour, une apoptose précoce des cellules gliales du cortex favorise la croissance tumoral, soulignant une interaction à double sens entre ces deux populations. Une analyse transcriptionnelle des cellules gliales du cortex durant la croissance tumorale a révélé des voies de signalisation augmentées ou réduites, et dont la fonction est en train d'être testée. En parallèle, prenant avantage d'une analyse transcriptionnelle de telles tumeur déjà disponible, j'ai sélectionné plusieurs candidats potentiels servant de médiateurs des interactions entre protéines à l'interface entre la tumeur et les cellules gliales. Enfin, j'ai évalué le rôle des protéines Rab dans la croissance tumorale. Ces travaux permettront de mieux comprendre comment les tumeurs des CSN envahissent et progressent dans les tissus sains<br>Primary brain tumours are extremely aggressive, and often incurable. Interestingly, cells sharing many of the features of neural stem cells (NSCs) have been identified in several primary brain tumors. These cells are coined cancer stem cells (CSCs), and display self-renewal potential with illimited proliferation. Tumours strongly depend on a cellular microenvironment, which results in part from the remodelling of pre-existing populations, such as glial cells and blood vessels (the blood-brain barrier). The project uses the Drosophila Central Nervous System as an in vivo model to track brain tumors during the entire life of the host. The fly NSCs are a well-characterised stem cell model from which tumous can be generated during development, are CSC-driven and can survive and proliferate extensively during adulthood. In this system I can discriminate between different cell populations within the niche, and explore their behavior with respect to the CSCs during tumor growth. In particular I am interested in the mechanisms of cellular interactions happening in glial cells at the interface with the tumors. My results show that a sub-population of glial cells (cortex glia) undergoes apoptosis upon tumor growth, a mechanism that appears to promote tumor propagation. Interestingly, preventing cortex glia death leads to reduced tumor growth, suggesting that the tumour is at least in part required to eliminate glia to grow. In return, precocious killing of cortex glia favors tumor growth, pinpointing a reciprocal relationship between these two cell populations. Performing a transcriptional analysis of cortex glia during tumor growth has revealed multiple signalling pathways with a changing expression, and whose functional relevance is currently being assessed. In parallel, taking advantage of a published tumor transcriptome, I have selected several potential candidates mediating protein protein interactions at the interface between the tumour and the glia cells. Finally, I have also evaluated the role of known Rab proteins in the context of tumor development. This on-going work will shed light on how CNS tumors progress within and invade the healthy tissue
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Reich, Thomas R. [Verfasser]. "The role of inhibitor of apoptosis proteins and XAF1 in the resistance to anti-cancer treatment in brain tumor cells and high-grade gliomas / Thomas R. Reich." Mainz : Universitätsbibliothek Mainz, 2017. http://d-nb.info/1132545323/34.
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