Simultaneous optical imaging and MRI of a dorsal skin-fold window chamber mouse model is investigated as a novel methodology to study the tumor microenvironment. Simultaneous imaging with two modalities allows for cross-validation of results, integration of the capabilities of the two modalities in one study and mitigation of invasive factors, such as surgery and anesthesia, in an in-vivo experiment. To make this investigation possible, three optical imaging systems were developed that operated inside the MRI scanner. One of the developed systems was applied to estimate vascular kinetic parameters of tumors in a dorsal skin-fold window chamber mouse model with simultaneous optical and MRI imaging. The target of imaging was a molecular agent that was dual labeled with both optical and MRI contrast agents. The labeling of the molecular agent, characteristics of the developed optical systems, the methodologies of measuring vascular kinetic parameters using optical imaging and MRI data, and the obtained results are described and illustrated.

Isotopic methods have been developed over the last 10 years as a method for determining chemical interactions of chlorinated solvents. These methods are especially promising for. This study attempts to employ and develop compound specific isotopic analyses of TCE and cDCE, along with chemical data, to characterize the degradation of TCE in a fractured bedrock aquifers. The Smithville site is a contaminated field site with extremely high levels of TCE contamination that is currently undergoing monitored remediation. From December 2008 until April 2010 extended samples were collected from the site to provide additional data analyses including isotopic data. The redox conditions at the site are anoxic to reducing, with sulfate reduction and methanogenesis as dominant terminal electron accepting processes. Redox data indicates that well electrochemical conditions are highly variable within the site, including areas near the source zone that not very reducing. Documented changes in groundwater conditions to much more reducing environments indicate that oxidation of organic matter is occurring at the Smithville site in select wells. Chemical analyses of TCE, DCE, VC, ethene and ethane are employed determine whether reductive dechlorination was occurring at the site. Results of field testing indicate that many wells on site, especially in the proximity of the source zone, dechlorination products were found. The isotopic data had a high range in both carbon and chlorine isotopes. Chlorine isotopic data ranges from a δ37Cl(TCE) of 1.39 to 4.69, a δ37Cl(cDCE) of 3.57 to 13.86, a δ13C(TCE) of -28.9 to -20.7, and a δ13C(cDCE) of -26.5 to -11.82. The range in values indicate varying degrees of degradation throughout the site, with the same wells grouping together. Combined chemical, redox and isotopic data shows that degradation seems to be a removal process for TCE at the Smithville site. Concentrations of chemicals created as a result of TCE degradation verify degradation, especially in wells 15S9, R7 and 17S9. Historically production of DCE in significant amounts, above 1.0 ppb, was observed to only occur after 2003. In addition to this, DCE data shows that the percentage of DCE made up of cDCE is above 96%. This indicates that microbes most likely mediate the processes that formed DCE from TCE. The linear regression of the delta-delta plot for isotopic TCE data shows line that is likely a direct function of the carbon and chlorine isotopic fractionation imparted upon the original TCE released. The slope found is consistent with data collected from other studies though cannot be applied to determining the process directly given the range of variability in isotopic field data.

Orientador: Miguel Arcanjo Areas / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-09T20:50:29Z (GMT). No. of bitstreams: 1 Santos_MonicaAlessandraTeixeirados_D.pdf: 1218402 bytes, checksum: c91dd447b33272e2f271723339af18ec (MD5) Previous issue date: 2008 / Resumo: Ratos Wistar recém desmamados foram expostos, por via oral, a deltametrina e permetrina para avaliação dos efeitos cardiotóxicos assim como o provável efeito protetor de fibras alimentares sobre a ação desses piretróides. O trabalho teve como objetivos específicos à avaliação eletrocardiográfica, o estudo histológico do fígado e coração e a determinação de resíduos no coração e fígado dos animais experimentais. Para tanto, o trabalho foi dividido em três partes: 1) Ensaio agudo, 2) Ensaio subcrônico, 3) Ensaio subcrônico + administração de fibras. Na primeira fase do experimento, os animais receberam doses equivalentes à 1/2 DL50, 1/5 DL50 e 1/10 DL50 de permetrina e deltametrina em dose única, com o objetivo de se determinar a menor dose onde se observa efeito agudo (LOAEL). Durante o ensaio biológico, os inseticidas foram administrados por gavagem com a utilização de óleo de milho (5 mL/kg) como veículo. Os animais do grupo controle receberam apenas óleo de milho, nas mesmas condições. Após a realização dos eletrocardiogramas (ECG) constatou-se que administração de 1/10 DL50 de permetrina e deltametrina foi a melhor dose para a realização do ensaio subcrônico de 28 dias. Durante o ensaio subcrônico, os piretróides foram administrados, diariamente, nas mesmas condições do ensaio agudo tendo sido verificado no ECG dos animais experimentais efeito cronotrópico negativo, prolongamento do intervalo PR e do complexo QRS, sugerindo retardo na condução dos estímulos dos átrios para os ventrículos. Além disso, o prolongamento dos intervalos QT e QTc indicaram retardo no processo de despolarização e repolarização ventricular, sugerindo risco de morte súbita. O complexo QRS apresentou maior prolongamento somente nos animais que receberam a deltametrina. Na terceira fase do experimento, foi avaliado o possível efeito protetor da pectina (fibra solúvel) e da celulose (fibra insolúvel), sobre a ação cardiotóxica dos piretróides, com a utilização da dose testada no ensaio subcrônico. A pectina se mostrou eficiente na redução dos efeitos tóxicos observados, já que sua presença aumentou a freqüência cardíaca e reduziu o intervalo PR, QT e QTc além do complexo QRS. A ingestão de celulose não alterou o quadro de toxicidade observado nos animais submetidos às substâncias testadas. Após o término dos ensaios subcrônicos, o coração e o fígado foram retirados dos animais experimentais para a avaliação histológica. O coração dos animais não apresentou alterações histológicas após a exposição a ambos os piretróides, no entanto, os fígados dos ratos que ingeriram deltametrina apresentaram células inflamatórias, hapatócitos irregulares, alterações citoplasmáticas, núcleo condensado e nucléolo indefinido. A exposição oral a permetrina induziu as mesmas alterações histológicas observadas nos fígados expostos a deltametrina, com exceção de infiltrações inflamatórias. A administração de pectina na dieta reduziu todas as alterações histológicas observadas anteriormente. No entanto, a celulose não se mostrou eficaz na proteção dos tecidos contra os efeitos histológicos dos piretróides estudados. Ao final do ensaio de toxicidade subcrônica, os resíduos de deltametrina e permetrina foram determinados no fígado e coração através do desenvolvimento/validação de método por cromatografia gasosa acoplada ao detector de captura de elétrons, não tendo sido detectada a presença destes resíduos nos tecidos estudados (LD < 0.9/0.2 para deltametrina e LD < 1/0.2 para permetrina em fígado e coração, respectivamente) / Abstract: The study was conducted on male wealing Wistar rats. They were exposed, by gavage, to deltamethrin and permethrin and the carditoxic effects of the pyrethroids and protective effects of dietary fibres were determinated. The purposes of this study were the eletrocardiographics evaluation, the histopathological study of the liver and heart and the residues determination in heart and liver of the rats. For that, this worky was divided in three parts: 1) Acute exposure, 2) Subchronic exposure, 3) Subchronic exposure + dietary fibres. In the first step, the animals were exposed to LD50, ½ LD50, 1/5 LD50 and 1/10 LD50 of permethrin and deltamethrin to determinate the lowest (LOAEL) dose which the acute effect could be observed. The insecticides were administrated in corn oil (5 ml/kg), intragastrically, in a single dose. Parallel studies were conduced in a control group that received only corn oil. The ECG records showed that 1/10 LD50 dose of permethrin and deltamethrin was the best dose for the conduction of subchronic assay. The experimental groups received the pyrethroids once a day for 28 days, in the same conditions of the first study. The subchronic poisoning resulted in negative chronotropism, prolongation of the PR interval and QRS complex, suggesting decrease of the stimulus from the atriums to ventricles. Besides, the prolongation of QT and QTc intervals indicated a decrease of the despolarization and repolarization processes suggesting sudden cardiac death. The QRS complex prolongation appeared only in the animals that received deltamethrin. In the third fase, the possible protective effects of pectin (soluble fiber) and cellulose (insoluble fiber) on pyrethroids cariotoxicity were evaluated. For this study, 1/10 LD50 dose was utilizated. Pectin increased the heart rate and decreased the PR, QT and QTc intervals and QRS complex, showing be efficient in reducing the cardiotoxicity. The ingestion of cellulose did not change the effects in heart observed in experimental animals. After the subchronic exposition, the heart and liver were taken in order to evaluate histologic changes. No changes were observed in the hearts of the rats exposed to both of pyrethroids. However, the liver of the animals exposed to deltamethrin showed inflamatory cells, irregular hepatocytes, cytoplasmatic changes, condensed nucleus and indefinite nucleolus. The permethrin induced the same histological changes observed in the livers exposed to the deltamethrin, exception of the inflamatory infiltrations. The pectin in the diet reduced all the histological changes previously observed and the cellulose did not efficient in the protection of the studied tissues. In the end of the subchronic essay, the tissue residues levels of permethrin and deltamethrin in heart and liver were estimated by gas chromatography with electron-capture detection. Residues of permethrin and deltamethrin were not observed in the studied tissues. (LOD < 0.9/0.2 for deltamethrin and LOD < 1.0/0.2 for permethrin in liver and heart, respectively) / Doutorado / Doutor em Ciência de Alimentos

Background: Angiogenesis is the process by which new blood vessels develop from existing vasculature and is a critical step in all tumours to facilitate growth beyond a few millimetres. As this process is largely inactive in physiological circumstances in adults, it represents an attractive therapeutic target in oncology. Drugs that target the angiogenic process are classified as anti-angiogenic agents. The first anti-angiogenic drug to be approved by the FDA was bevacizumab; a recombinant humanized monoclonal antibody against VEGF. Randomised studies in colorectal cancer (and other solid malignancies) have reported prolonged progression free survival and overall survival for bevacizumab. However, standard radiological criteria, Response Evaluation Criteria In Solid Tumours (RECIST), although widely employed to assess response to therapy in clinical trials, are generally insensitive to the predominantly cytostatic effects of anti-angiogenic and other targeted therapies. Alternative methods of predicting or assessing early response to such agents are needed, particularly given the cost and toxicity implications of such treatments. However, biomarkers to aid selection of patients for anti-angiogenic therapies, including bevacizumab, remain elusive. Purpose: To investigate Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI), Diffusion Weighted Imaging (DWI) and circulating angiocytokines, measured using an ELISA multiplex, as prognostic markers in patients with metastatic colorectal cancer treated with bevacizumab and chemotherapy. Results: Seventy patients were treated. DCE-MRI and DWI parameters showed good reproducibility with coefficient of variation between 3.7 to 23% for parameters. The median progression free survival, the primary end point of the trial, was 9.3 months. The overall response rate was 44%. The clinical variables which were significant for progression free survival on univariate analysis were: performance status (p=0.005), CEA (p=0.04) and serum LDH (p=0.005). Biomarkers which were significant for progression free survival on univariate analysis were serum VEGF-A (p=0.02), serum HGF (p=0.005), sVEGFR-2 (p=0.02). In each case, low values of the biomarker were associated with improved outcome. Multivariate analysis identified Ktrans (p=0.015), performance status (p=0.008) and serum HGF (p=0.003) as the most significant predictors of progression free survival. A prolonged progression free survival was associated with a good ECOG performance status, high Ktrans and low serum HGF.Conclusions: Whilst these results are encouraging, future work is required to establish whether HGF and Ktrans are prognostic markers for metastatic colorectal cancer and their precise role in the prediction of patients likely to benefit from treatment with bevacizumab.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第22741号 / 医博第4659号 / 新制||医||1046(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 辻川 明孝, 教授 伊達 洋至, 教授 羽賀 博典 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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In Dynamic Contrast Enhanced MRI there are several steps from the initial signal to obtaining the pharmacokinetic parameters for tumor characterization. The aim of this work was to validate the steps in the flow of data focusing on T1-mapping, Contrast Agent (CA)-quantification and the pharmacokinetical (PK) model, using a digital phantom of a head. In the Digital Phantom tissues are assigned necessary values to obtain both a regular and contrast enhanced (using Parker AIF) representation and simulating an SPGR signal. The data analysis was performed in a software called MICE, as well as the Digital Phantom developed at the department of Radiation Sciences at Umeå University. The method of variable flip angles for the T1-mapping was analyzed with respect to SNR and number of flip angles, finding that the median value in each tissue is correct and stable. A "two point" inversion recovery sequence was tested with optimal combination of inversion times for white matter and CSF and obtaining correct T1-values when the inversion times were close to the tissue T1, otherwise with large deviations seen. Three different methods for CA-quantification were analyzed and a large underestimation was found assuming a linearity between signal and CA-concentration mainly for vessels at about 60%, but also for other tissue such as white matter at about 15%, improving when the assumption was removed. Still there was a noticeable underestimation of 30% and 10% and the quantification was improved further, achieving a near perfect agreement with the reference concentration, taking the T2*-effect into account. Applying Kety-model, discarding the vp-term, Ktrans was found to be stable with respect to noise in the tumor rim but ve noticeably underestimated with about 50%. The effect of different bolus arrival time, shifting the AIF required in the PK-model with respect to the CA-concentration, was tested with values up to 5 s, obtaining up to about 5% difference in Ktrans as well as the effect of a vascular transport function obtained by the means of an effective mean transit time up to 5 s and up to about 5% difference in Ktrans.

L’échographie dynamique de contraste (DCE-US) est actuellement proposée comme technique d’imagerie fonctionnelle permettant d’évaluer les nouvelles thérapies anti-angiogéniques. Dans ce contexte, L'UPRES EA 4040, Université Paris-Sud 11, et le service d'Echographie de l'Institut Gustave Roussy ont développé une méthodologie permettant de calculer automatiquement, à partir de la courbe de prise de contraste moyenne obtenue dans la tumeur après injection en bolus d’un agent de contraste, un ensemble de paramètres semi-quantitatifs. Actuellement, l’état hémodynamique du patient ou encore les conditions d’injection du produit de contraste ne sont pas pris en compte dans le calcul de ces paramètres à l’inverse d’autres modalités (imagerie par résonance magnétique dynamique de contraste ou scanner de perfusion). L’objectif de cette thèse était donc d’étendre la méthode de déconvolution utilisée en routine dans les autres modalités d’imagerie à l’échographie de contraste. Celle-ci permet de s’affranchir des conditions citées précédemment en déconvoluant la courbe de prise de contraste issue de la tumeur par la fonction d’entrée artérielle, donnant ainsi accès aux paramètres quantitatifs flux sanguin, volume sanguin et temps de transit moyen. Mon travail de recherche s’est alors articulé autour de trois axes. Le premier visait à développer la méthode de quantification par déconvolution dédiée à l’échographie de contraste, avec l’élaboration d’un outil méthodologique suivie de l’évaluation de son apport sur la variabilité des paramètres de la microvascularisation. Des évaluations comparatives de variabilité intra-opérateur ont alors mis en évidence une diminution drastique des coefficients de variation des paramètres de la microvascularisation de 30% à 13% avec la méthode de déconvolution. Le deuxième axe était centré sur l’étude des sources de variabilité influençant les paramètres de la microvascularisation portant à la fois sur les conditions expérimentales et sur les conditions physiologiques de la tumeur. Enfin, le dernier axe a reposé sur une étude rétrospective menée sur 12 patients pour lesquels nous avons évalué l’intérêt de la déconvolution en comparant l’évolution des paramètres quantitatifs et semi-quantitatifs de la microvascularisation en fonction des réponses des tumeurs obtenues par les critères RECIST à partir d’un scan effectué à 2 mois. Cette méthodologie est prometteuse et peut permettre à terme une évaluation plus robuste et précoce des thérapies anti-angiogéniques que les méthodologies actuellement utilisées en routine dans le cadre des examens DCE-US. / Dynamic contrast-enhanced ultrasonography (DCE-US) is currently used as a functional imaging technique for evaluating anti-angiogenic therapies. A mathematical model has been developed by the UPRES EA 4040, Paris-Sud university and the Gustave Roussy Institute to evaluate semi-quantitative microvascularization parameters directly from time-intensity curves. But DCE-US evaluation of such parameters does not yet take into account physiological variations of the patient or even the way the contrast agent is injected as opposed to other functional modalities (dynamic magnetic resonance imaging or perfusion scintigraphy). The aim of my PhD was to develop a deconvolution process dedicated to the DCE-US imaging, which is currently used as a routine method in other imaging modalities. Such a process would allow access to quantitatively-defined microvascularization parameters since it would provide absolute evaluation of the tumor blood flow, the tumor blood volume and the mean transit time. This PhD has been led according to three main goals. First, we developed a deconvolution method involving the creation of a quantification tool and validation through studies of the microvascularization parameter variability. Evaluation and comparison of intra-operator variabilities demonstrated a decrease in the coefficients of variation from 30% to 13% when microvascularization parameters were extracted using the deconvolution process. Secondly, we evaluated sources of variation that influence microvascularization parameters concerning both the experimental conditions and the physiological conditions of the tumor. Finally, we performed a retrospective study involving 12 patients for whom we evaluated the benefit of the deconvolution process: we compared the evolution of the quantitative and semi-quantitative microvascularization parameters based on tumor responses evaluated by the RECIST criteria obtained through a scan performed after 2 months. Deconvolution is a promising process that may allow an earlier, more robust evaluation of anti-angiogenic treatments than the DCE-US method in current clinical use.

This dissertation deals with quantitative perfusion analysis of MRI contrast-enhanced image time sequences. It focuses on two so far separately used methods -- Dynamic contrast-enhanced MRI (DCE-MRI) and Dynamic susceptibility contrast MRI (DSC-MRI). The common problem of such perfusion analyses is the unreliability of perfusion parameters estimation. This penalizes usage of these unique techniques on a regular basis. The presented methods are intended to improve these drawbacks, especially the problems with quantification in DSC in case of contrast agent extravasation and instability of the deconvolution process in DCE using advanced pharmacokinetic models. There are a few approaches in literature combining DCE and DSC to estimate new parameters of the examined tissue, namely the relaxivity of the vascular and of the interstitial space. Originally, in this scheme, the 2CXM DCE model was used. Here various models for DCE analysis are tested keeping in mind the DCE-DSC combination. The ATH model was found to perform better in this setting compared to 2CXM. Finally, the ATH model was used in alternating DCE-DSC optimization algorithm and then in a truly fully simultaneous DCE-DSC. The processing was tested using simulated and in-vivo data. According to the results, the proposed simultaneous algorithm performs better in comparison with sequential DCE-DSC, unleashing full potential of perfusion analysis using MRI.