<p>Elderly committing suicide can be in a “preclinical phase” of dementia. Depressive symptoms may indicate a risk to develop a disease of dementia, for example Alzheimer’s Disease. Today almost 10% of the Swedish population older than 65 years suffer from a cognitive impairment diagnosed as dementia. Symptoms of dementia are associated with degenerative changes in the brain caused by a deposition of amyloid, leading among others things to a nerve cell death. A clinical diagnosis can be hard to set, and a definitive diagnose can only be set after a pathological examination, which only is possible after death. For this study we used Congo red staining of brains sections to find amyloid in autopsies from elderly people committing suicide. 35 cases (>60 year) were studied. Of the 35 cases 1/3 showed to be positive for amyloid deposition. This result in addition to other studies suggest that depressive symptoms is a “preclinical phase” of dementia, and therefore the suicide risk for this group must be consider to be elevated. However, more reliable prospective studies most be done to confirm this retrospective study.</p>

Elderly committing suicide can be in a “preclinical phase” of dementia. Depressive symptoms may indicate a risk to develop a disease of dementia, for example Alzheimer’s Disease. Today almost 10% of the Swedish population older than 65 years suffer from a cognitive impairment diagnosed as dementia. Symptoms of dementia are associated with degenerative changes in the brain caused by a deposition of amyloid, leading among others things to a nerve cell death. A clinical diagnosis can be hard to set, and a definitive diagnose can only be set after a pathological examination, which only is possible after death. For this study we used Congo red staining of brains sections to find amyloid in autopsies from elderly people committing suicide. 35 cases (&gt;60 year) were studied. Of the 35 cases 1/3 showed to be positive for amyloid deposition. This result in addition to other studies suggest that depressive symptoms is a “preclinical phase” of dementia, and therefore the suicide risk for this group must be consider to be elevated. However, more reliable prospective studies most be done to confirm this retrospective study.

Prion diseases are fatal and incurable neurodegenerative diseases that share many pathological similarities to other neurodegenerative diseases such as Alzheimer’s or Parkinson’s disease. One of the earliest pathological signs commonly detected in all of these diseases is the dysfunction followed by loss of neuronal synapses, spines and eventually dendrites that collectively contribute to disruption of normal brain function. These pathologies tend to progressively accumulate within the brain tissue such that extensive damage typically precedes clinical symptom manifestation and ultimate death of neurons. Clearly, understanding the molecular processes responsible for these pathologies could uncover critical pathway(s) that are responsible for propagating this brain damage and could therefore be exploited for therapy development. However, molecular mechanisms implicated in this early pathology remain unidentified. To address this gap in knowledge, this thesis describes a transcriptional approach coupled with specific isolation of neuronal-enriched tissue which was used to help delineate cellular pathways involved in prion-induced neurodegeneration. Profiling cell bodies of CA1 hippocampal neurons known to be affected during early prion disease revealed temporal alteration in both gene and microRNA (gene regulators) expression throughout disease. On a gene expression level, changes in transcript expression during preclinical disease were reminiscent of an activity-dependent neuroprotective gene signature previously described in the literature. These neuroprotective genes were induced during preclinical disease, diminished as disease progressed and were abolished at clinical disease. In support of this process, upregulation of the phosphorylated form of the neuroprotective transcription factor CREB was detected during preclinical disease in these neurons. Furthermore, several genes known to be induced by CREB were also upregulated at preclinical disease in prion-infected mice. Interestingly, expression of numerous deregulated microRNAs paralleled the neuroprotective gene signature of which several are known to remodel neuronal spines and dendrites. To determine whether other preclinically induced microRNAs were also capable of remodeling neuronal structures, gain-of-function studies were performed in primary mouse hippocampal neurons for the uncharacterized miR-26a-5p. Neurons over-expressing miR-26a-5p had enhanced spine density and dendrite arborization, similar to other preclinically-induced microRNAs. Together, these data suggests that CA1 hippocampal neurons induce a neuroprotective transcriptional signature that is evident early in the course of disease within CA1 hippocampal neurons and is abolished by clinical disease. Reestablishment of key molecules that can induce this neuroprotective signature at a time when these genes begin to dissipate could prolong prion disease onset and delay clinical symptom manifestation. / October 2015

Delayed or impaired bone healing occurs in 5-10% of all fractures, yet cost effective solutions to enhance the healing process are limited. Lithium, a current treatment for bipolar disorder, is not clinically indicated for use in fracture management, but has been reported to positively influence bone biology. The objective of this study was to identify lithium administration parameters that maximize bone healing in a preclinical, rodent femur fracture model. Using a three factor, two level, design of experiments (DOE) approach, bone healing was assessed through mechanical testing and &mu;CT-image analysis. Significant improvements in healing were found at a low dose, later onset, longer duration treatment combination, with onset identified as the most influential parameter. The positive results from this DOE screening focuses the optimization phase towards further investigation of the onset component of treatment, and forms a crucial foundation for future studies evaluating the role of lithium in fracture healing.

Delayed or impaired bone healing occurs in 5-10% of all fractures, yet cost effective solutions to enhance the healing process are limited. Lithium, a current treatment for bipolar disorder, is not clinically indicated for use in fracture management, but has been reported to positively influence bone biology. The objective of this study was to identify lithium administration parameters that maximize bone healing in a preclinical, rodent femur fracture model. Using a three factor, two level, design of experiments (DOE) approach, bone healing was assessed through mechanical testing and &mu;CT-image analysis. Significant improvements in healing were found at a low dose, later onset, longer duration treatment combination, with onset identified as the most influential parameter. The positive results from this DOE screening focuses the optimization phase towards further investigation of the onset component of treatment, and forms a crucial foundation for future studies evaluating the role of lithium in fracture healing.

Imaging Iodine-125 requires an increased focus on developing an understanding of how fundamental processes used by imaging systems work to provide quantitative output for the imaging system. Isotopes like I-125 pose specific imaging problems that are a result of low energy emissions as well as how closely spaced those emissions are in the spectrum. This work seeks to characterize the performance of a small animal SPECT-CT imaging system with respect to imaging I-125 for use in a preclinical translational research environment and to understand how the performance of this system relates to critical applications such as attenuation and scatter correction. The specific aims of this work examined several key areas of system function and performance with respect to I-125 imaging. The first aim examined the geometric SPECT calibration routine used for the Inveon imaging system with a particular focus on determining the accuracy of the calibration as well as the robustness of the algorithm under routine and adverse imaging conditions. The second aim was to characterize detector uniformity issues that may arise by comparing the uniformity performance of the system with both I-125 and Co-57 as well as examining the possibility of altering the acquisition method for normalization scans to increase the uniformity performance. The third aim sought to optimize the energy window used for acquisition of I-125 data and to determine the effects the selection of the window had on valid and scatter events. The fourth aim used the optimized windows, determined by the third aim, to assess the performance of a reconstruction algorithm, currently under development, that corrects for attenuation and scatter effects. The fifth and final aim of this work sought to assess the feasibility acquiring SPECT-CT data simultaneously and to assess the quality of data that could be achieved if simultaneous acquisition of the two imaging modalities was, in fact, possible. This work met these aims by performing an extensive series of studies examining the response of the system to I-125 imaging. These included multiple series of phantom imaging using both manufacturer as well as custom-designed sources for use with measurements involving I-125 and Co-57. Statistics from over 60 datasets with analysis in greater than 480 regions of interest were used for the analysis of attenuation and scatter correction data alone. The final study involving simultaneous SPECT-CT acquisition required modification of the imaging hardware to enable this type of data collection as well as development of a reconstruction algorithm to correctly handle the CT data acquired in a step-and-shoot helical mode. A number of key findings resulted from this work including the validation of the calibration routine of this imaging system, even under non-ideal imaging conditions for both the SPECT and CT modalities. Uniformity performance with I-125 was found to be a challenge with this imaging system but reductions in performance compared to other isotopes were not significant enough to introduce severe artifacts into the image data. Optimization of I-125 parameters resulted in improvements of the processed data indicating that the recommended settings provided by the manufacturer could be altered to provide results that better balance between minimizing scatter effects and maximizing detection of valid events. Assessment of the proposed scatter and attenuation correction algorithm for this system showed marked improvement as compared to data processed without these corrections. The final study of simultaneous SPECT-CT imaging proved this acquisition method to be feasible on a commercial system with minimal The primary conclusions drawn from this study indicate that the system is adequate for imaging with I-125 when care is taken to properly maintain the system as well as keeping sources current and properly centered in the scanner field of view during calibration. The study strongly illustrates the necessity of compensating any data collected using I-125 for attenuation and scatter effects; with some regions showing greater than 25% attenuation and approximately 30% improvement in quantitative values for scatter affected regions with the corrections applied. The study also concludes that simultaneous SPECT-CT is feasible with minor adjustments to a commercial platform.

Functional Magnetic Resonance Imaging (fMRI) based studies are rapidly expanding in the field of preclinical research. The majority of these studies use Echo Planar Imaging (EPI) to measure Blood Oxygenation Level Dependent (BOLD) signal contrasts in the brain. In such studies the magnitude and statistical significances of these contrasts are then related to brain function and cognition. It is assumed that any observed signal contrast is ultimately due to differences in biological state and that scanner performance is stable and repeatable between subjects and studies. However, due to confounding issues introduced by in vivo subjects, little work has been undertaken to test this basic assumption. As the BOLD signal contrasts generated in such experiments are often very low, even small changes in scanner performance may dominate the BOLD contrast, distorting any biological conclusions drawn. A series of fMRI phantoms were produced to measure scanner performance independent of biological subjects. These phantoms produce specified signal contrast levels on demand during an fMRI scan by means of current-induced magnetic field gradients. These were used to generate data sets that emulated the BOLD signal contrast of in vivo imaging. Two studies examining scanner performance were then conducted on high-field preclinical MRI scanners. Firstly, in a longitudinal study on a single scanner, measurements were taken over a number of days across a week long period and then every two months over a year long period. Secondly, the behaviour of four preclinical scanners (three at 7T, one at 9.4T) was comparatively assessed. Measurements of several imaging parameters including contrast generated and functional contrast to noise ratio (fCNR) were obtained in both studies. If the scanners involved are truly comparable then they should generate similar measurement values. Across both studies parameter measurements showed significant differences for identical contrast settings on the phantom. Although signal contrast itself proved very comparable across the studies fCNR proved to be highly variable. As well as these measurements of longer tem behaviour proving variable, short and mid-term signal stability displayed a wide range of variability. Variations in the level and quality of both signal and noise were observed. Modelling of signal changes based on fundamental physical principles was also performed for comparison. The impact of these behaviours and variations on in vivo studies could result in skewed biological conclusions at any single site, with some sites exhibiting greater problems than others. The multisite results suggest potential difficulties when comparing biological conclusions between sites, even when using identical imaging parameters. In summary, these results suggest that a cautious approach should be taken with the conclusions of both fMRI and associated resting state connectivity studies that use EPI as their acquisition sequence. Improvements to both the experimental design of studies and regular quality monitoring of scanners should be undertaken to minimise these effects. Clinical MRI scanners should also be assessed for similar aberrations in behaviour.

Avec 42 000 nouveaux cas diagnostiqués en 2012, le cancer colorectal (CCR) représente en France le troisième cancer en termes d’incidence. Les métastases, qui surviennent principalement au niveau du foie et des poumons, en constituent la principale cause de décès. Malgré les progrès récents de la chimiothérapie et des agents ciblés, le taux de survie à 5 ans des patients présentant un CCR métastasé reste faible. Aujourd’hui, la résection chirurgicale est le seul traitement curatif, cependant moins de 20% des patients porteurs de métastases sont opérables. Il existe donc un grand nombre de patients présentant un CCR métastasé pour lequel aucun traitement curatif ne peut être proposé. La formation des métastases à partir d’une tumeur primaire résulte d’une longue série d’étapes séquentielles liées les unes aux autres. L’issue de ce processus dépend à la fois des propriétés intrinsèques des cellules tumorales et de la réponse de l’hôte. Il a récemment été montré que les couples chimiokines/récepteurs interviennent dans le contrôle des différentes étapes de la progression tumorale.Le projet de recherche développé au cours de mon travail de thèse avait pour objectif d’utiliser les chimiokines et leurs récepteurs dans de nouvelles stratégies thérapeutiques pour bloquer et/ou éradiquer les métastases hépatiques et pulmonaires des CCRs. Le travail s’est articulé selon deux axes dans lesquels nous avons montré d’une part que, le blocage du récepteur de chimiokines CXCR7 permet de limiter les métastases pulmonaires de CCRs et d’autre part que, le transfert de gène codant CX3CL1 au niveau du foie entraîne une réponse anti-tumorale efficace dans les métastases hépatiques de CCRs. / With 42 000 newly-diagnosed patients in 2012, the colorectal cancer (CRC) represents the third type of cancer in terms of incidence in France. The leading cause of death from CRC is the development of metastases and these metastases will occur mostly within the liver (50% of the patients) and within the lungs (15%). Despite recent progress, notably in the chemotherapies now used and the targeted agents, the rate of 5-years survival for late stage CRC remains low. Nowadays, the surgical resection is the only curative treatment proposed to patients with metastatic CRC, however less than 20% of them have an operable tumour. There is therefore a high number of patients for whom no cure is currently available. A primary tumour’s dissemination to a second organ is the result of a long process made of numerous cross-linked steps. The final outcome of this process depends on the intrinsic properties of tumour cells as well as the host response. Recently, it has been shown that the chemokine-chemokine receptor pairs (initially described as regulating the leukocyte migration) play crucial roles in the various stages involved in tumour progression. The aim of the research project developed during my PhD was to assess the use of the chemokines and their receptors in new therapeutic strategies to block and/or eradicate the hepatic and pulmonary metastases of CRC. Our work has been organized along two main lines of approach. We have shown that the blockage of the CXCR7 chemokine receptor enables the limitation of the CRC metastases within the lungs and that the CX3CL1 gene transfer into the hepatocytes leads to an efficient anti-tumor response in the CRC metastases within the liver.

Submitted by Maike Costa (maiksebas@gmail.com) on 2017-09-11T11:28:08Z No. of bitstreams: 1 arquivototal.pdf: 1135288 bytes, checksum: d807f92b4e8e4ae03efbf3563f40f411 (MD5) / Made available in DSpace on 2017-09-11T11:28:09Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1135288 bytes, checksum: d807f92b4e8e4ae03efbf3563f40f411 (MD5) Previous issue date: 2015-02-28 / Medicinal plants are used in the treatment of various diseases, often indiscriminately, without prior knowledge of possible toxic effects due to their use. In this context, it is essential to carry out toxicological studies of medicinal plants. Zornia brasiliensis (Fabaceae), popularly known as "urinária", "urinana" and "carrapicho", is used by the population as a diuretic. Previous studies reported antioxidant activity and cytotoxicity in brine shrimp larvae. As there are no reports in the literature of its possible in vivo toxicity, the assessment of the toxicological profile is essential for safe use by the population as well as to support the conduct of clinical trials and subsequently the production of an herbal formulation. Thus, this study aimed to evaluate the preclinical toxicity of alcoholic extract of aerial parts of Zornia brasiliensis (EHZB). The value of HC50 obtained in hemolysis assay was 1.954 (1840-2074) / mL, demonstrating that the extract has low toxicity in mouse erythrocytes. During the preclinical acute toxicity test, there were no deaths nor behavioral changes in mice treated with 2000 mg / kg EHZB. There was a significant decrease in feed intake in male animals compared to the control group, however, there was no significant change in weight gain of animals, which showed weight regain after the treatment. No significant difference was observed in the organs indexes (heart, liver, kidneys, spleen and thymus) after acute treatment with EHZB. As regards the evaluation of preclinical repeated dose toxicity (28 days), death was no evidenced in animals treated with the EHZB (250, 500 and 1000 mg / kg) as well, there were no significant changes in weight gain and body temperature of the animals. The EHZB administration resulted in a significant increase in AST and ALT activities in male animals (1000 mg / kg) and in female animals treated with all doses there was increased ALT activity, suggesting the induction of hepatic toxicity by the extract. However, no significant clinical finding was observed in liver histopathology, suggesting that these changes were minor and not damaged the tissue structure. Changes in hematological parameters and exploratory activity were demonstrated, especially with the higher dose of the extract. The results did not show any change in the index of the organs, nor significant changes were revealed in the histopathological study in liver and kidneys. Moreover, EHZB showed no genotoxic activity in vivo, evaluated by micronucleus test in peripheral blood (2000 mg / kg). The data shows that EHZB has low pre-clinical toxicity. / As plantas medicinais são utilizadas no tratamento de diversas doenças, muitas vezes, de forma indiscriminada, sem o conhecimento prévio de possíveis efeitos tóxicos decorrentes de seu uso. Nesse contexto, torna-se imprescindível a realização de estudos toxicológicos de plantas medicinais. Zornia brasiliensis (Fabaceae), popularmente conhecida como "urinária", "urinana" e "carrapicho", é usada pela população como diurético. Estudos com a espécie relataram atividade antioxidante e citotóxica em larvas de Artemia salina. Como não há relatos na literatura de sua possível toxicidade in vivo, a avaliação do perfil toxicológico é essencial para o uso seguro pela população, bem como para subsidiar a realização de ensaios clínicos e posteriormente a produção de um medicamento fitoterápico. Desse modo, o presente estudo objetivou avaliar a toxicidade pré-clínica do extrato hidroalcoólico das partes aéreas de Zornia brasiliensis (EHZB). O valor de CH50 obtido no ensaio de hemólise foi 1.954 (1.840 - 2.074) μg/mL, demostrando que o extrato apresenta baixa toxicidade em eritrócitos de camundongos. Durante o ensaio de toxicidade pré-clínica aguda, não ocorreram mortes nem alterações comportamentais nos camundongos tratados com 2.000 mg/kg do EHZB. Houve diminuição significativa no consumo de ração nos animais machos em comparação ao grupo controle, entretanto, não houve alteração significativa na evolução ponderal dos animais, os quais apresentaram a recuperação do peso ao final do tratamento. Nenhuma diferença significativa foi observada nos índices dos órgãos (coração, fígado, rins, baço e timo) após tratamento agudo com EHZB. No tocante à avaliação da toxicidade pré-clínica de doses repetidas (28 dias), não foram evidenciadas mortes nos animais tratados com o EHZB (250, 500 e 1000 mg/kg) como também, não foram observadas alterações significativas na evolução ponderal e temperatura corporal desses animais. A administração de EHZB resultou em um aumento significativo da atividade de AST e ALT nos animais machos (1000 mg/kg), e nos animais fêmeas tratados com todas as doses houve aumento da ALT, sugerindo a indução de toxicidade hepática pelo extrato. No entanto, nenhum achado clínico importante foi observado na histopatologia do fígado, sugerindo que essas alterações são leves e não danificaram a estrutura do tecido. Alterações nos parâmetros hematológicos e na atividade exploratória foram demonstradas, especialmente, com a maior dose do extrato. Os resultados não evidenciaram qualquer alteração no índice dos órgãos, nem tampouco, foram reveladas alterações significativas no estudo histopatológico realizado em fígado e rins. Ainda, EHZB não apresentou atividade genotóxica in vivo no ensaio de micronúcleo em sangue periférico (2000 mg/kg). Os dados permitem concluir que EHZB apresenta baixa toxicidade pré-clínica.

A medicina nuclear é a área da ciência médica que usa radiofármacos, isto é um radionuclídeo ligado a uma molécula de interesse biomédico, para estudar o funcionamento do organismo. Com isso, essa ciência pode realizar diagnósticos de patologias ou tratamento oncológico. Os estudos pré-clínicos, estudo com pequenos animais, são requisitos de suma importância para o desenvolvimento dessa área. São esses estudos que permitem os testes de novos radiofármacos que possivelmente serão usados em humanos. Quando se trata de pequenos animais, os órgãos de estudo são muito pequenos, portanto é vital que o equipamento tenha uma ótima resolução espacial e boa sensibilidade. Na medicina nuclear, a tomografia por emissão de pósitron (Positron Emission Tomography, PET) tem as características necessárias para desenvolver esses estudos com pequenos animais. Os animais mais usados são ratos e camundongos, e como nem sempre esses animais representam modelo humano seria interessante ter um equipamento que também funcionasse em outros animais. Sendo esse tomógrafo caro, não é viável ter um equipamento para cada tipo de animal. O presente trabalho propõe justamente um único tomógrafo que possa ser usado em diferentes animais ou eventualmente em dois animais simultaneamente. Isso será alcançado variando o anel de detecção usado nesse tipo de tomógrafos. Isso é alcançado mais facilmente em geometrias retangulares, pois com apenas 4 hastes se consegue variar a distância máxima entre os detectores preservando a forma da geometria. O custo envolvido na construção física desse tomógrafo é elevado, consequentemente é interessante ter um teste preliminar que forneça dados que possam sustentar essa ideia. A melhor alternativa para esse teste é o uso de simulação computacional. GATE (Geant4 Application for Tomographic Emission) foi o programa escolhido para essa simulação, porque já é um software validado, isto quer dizer que é compatível com experimentos reais. Assim sendo, quatro simulações foram montadas, duas para geometrias circulares com diâmetros diferentes, e analogamente, duas quadradas. Para verificar qual das geometrias tem melhor performance, foram usados os métodos sugeridos pela norma NEMA NU 4-2008. Efetuados esses testes, pode-se observar que as geometrias quadradas tem resolução semelhante às circulares. A sensibilidade e a relação sinal-ruído são maiores nas geometrias quadradas. Portanto, conclui-se que no geral, as geometrias retangulares simuladas são melhores que as circulares. Esse resultado é motivador para dar início à construção física do tomógrafo, pois o mesmo permite desenvolver novos produtos de modo mais eficiente e com menos custo / Nuclear medicine is an area of medical science that uses radiopharmaceutical (a radionuclide bounded to a molecule of biomedical interest) to study human physiology by images. Thus, this science can perform diagnostics of diseases and eventually, in specific cases, cancer treatment. Before using a new radiopharmaceutical in humans it is necessary to test it in small animals. The organs in these animals are very small, consequently it is vital that the equipment has a great spatial resolution and high sensitivity. In nuclear medicine Positron Emission Tomography (PET) has this requirement. The most animal used to develop this kind of studies are rats and mice. However, they are not always representing human animal model, so equipment that works to other animals also it would be interesting. But it is not feasible to have equipment for each animal, because it will be very expensive. Therefore, the aim of this work is test one scanner that can be used in different animals or possibly in two animals at the same time. This will be achieved by varying the detection ring used in this type of scanners (PET). To do it, it is easier using rectangular geometries because moving only four stalks the distance between the detectors can be varied preserving the shape of the geometry. The cost involved in physical construction of this kind of tomograph is too high, therefore it is interesting have a preliminary test that provides some data which supports this idea. Computer simulation is a cheap alternative for this test and it is able to provide a reliable data. The software used to do the simulations was GATE (Geant4 Application for Tomographic Emission) because it has already validated, what means it is compatible with real experiments. Thus, four simulations were builded, two for circular geometries with different diameters and two for rectangular geometries. To check which kind of geometry has better performance, it used the methods suggested by NEMA NU 4-2008. At end of these tests, it is possible to observe that the spatial resolution in square geometries is similar to circular. The sensitivity and signal to noise ratio are higher in the square geometries. So, in general, it is concluded that the simulated rectangular geometries are better than circular certainly, this result can be motivating to begin physical construction of the scanner, as it allows developing new products more efficiently and with less cost.