1,615 research outputs found
ETUDE DE L'ANGIOGENÈSE PAR PET CARDIAQUE AU 68GA- NODAGA-RGD DANS LES LÉSIONS MYOCARDIQUES SUBAIGUËS ET CHRONIQUES
Contexte: Les maladies cardiovasculaires sont la première cause de décès dans le monde représentant à elles seules 30% des décès. Dans ce groupe, les pathologies coronariennes occupent la première place. Parmi celles-ci, figurent les infarctus aigus du myocarde et les occlusions totales chroniques.
La prolifération de vaisseaux sanguins nouvellement formés, appelé néoangiogenèse, est au centre de nombreux processus physiologiques et pathophysiologiques dont la réparation du muscle cardiaque après une lésion ischémique. Un marqueur particulièrement spécifique de l'angiogenèse est l'intégrine αvβ3. Il a été démontré chez l'animal que l'angiogenèse était un processus quantifiable et prédicateur du remodelage cardiaque après une lésion ischémique. L'imagerie de ce processus chez l'homme pourrait permettre une meilleure évaluation et un meilleur suivi des patients se présentant avec une pathologie coronarienne.
Objectifs: Évaluer par imagerie PET l'angiogenèse au cours du temps chez des patients se présentant pour un infarctus du myocarde à plus de 24 heures d'occlusion ou une occlusion totale chroniques. Le but sera d'établir le profil d'évolution de ce marqueur et de mettre cella en perspective avec l'évolution clinique des patients.
Méthodes: Utilisation du PET cardiaque couplé à un traceur radioactif marqueur de l'intégrine αvβ3, le 68Ga-NODAGA-RGD. Celui-ci sera réalisé au cours d'un examen PET
permettant une mesure de la perfusion cardiaque par 82Rubidium chez des patients se présentant pour un infarctus du myocarde ou une occlusion chronique totale. L'ensemble de la procédure serait réalisée trois fois : 2 à 3 semaines après l'admission, un mois après celle-ci, et finalement 3 mois après l'admission.
Résultats escomptés: On s'attend, chez les patients se présentant pour un infarctus aigu du myocarde, à un pic de détection de l'intégrine αvβ3 lors de la première
mesure puis à une diminution des valeurs au fil des mois. En ce qui concerne les patients se présentant pour une occlusion totale chronique, dont le temps d'ischémie du myocarde est inconnu mais supérieur à 3 mois par définition, le profil sera à priori différent et le niveau d'intégrine pourrait s'atténuer avec la réouverture de l'occlusion. La connaissance de l'évolution de l'angiogenèse, de son étendue et de son activité intrinsèque mesurés in vivo chez l'homme par PET au 68Ga-NODAGA-RGD seront mis en relation avec l'évolution clinique du patient.
Plus-value escomptée: Les conclusions de l'étude devraient apporter une meilleure compréhension du processus physiopathologique de l'ischémie du myocarde et
plus particulièrement de l'évolution de l'angiogenèse lors de ce processus pathologique. L'évaluation et la prise en charge thérapeutique d'un patient avec une artère coronaire occluse pourraient être améliorées dans la mesure où cela représente encore aujourd'hui un défi pour le cardiologue
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Development and validation of a new glaucoma screening test using temporally modulated flicker
Purpose
Describing the psychometric characteristics and diagnostic accuracy of the Accelerator 4‐Alternative Forced‐Choice Flicker Test prototype (A4FTp) for detecting chronic open angle glaucoma (COAG).
Methods
A4FTp measures temporally‐modulated flicker thresholds in regions of the visual field with high susceptibility to glaucomatous loss. We initially evaluated its psychometric properties on 20 normals (aged 33.8 ± 8.5 years) who were tested multiple times over a period of 3 months. All subjects underwent four repetitions for shorter (T8) and longer (T12) staircase termination criteria, to determine the most suitable threshold criterion. Four randomly selected subjects underwent a total of 10 repetitions to study test‐retest repeatability and learning effects. To determine its diagnostic accuracy, one eye of 40 participants with COAG and 38 normal controls were tested with the A4FTp in comparison with the Frequency Doubling Technology (FDT; C20‐5 programme) and iVue Spectral Domain Optical Coherence Tomography (SD‐OCT). Tests were conducted in a random order with results masked to the clinician conducting the reference ophthalmic examination. The accuracy of each test was determined by analysis of the area under the receiver operator characteristic curve (AUROC).
Results
A4FTp flicker thresholds were stable, with standard deviations of only 0.52 decilog (dL) for T8, increasing to 1.32 dL for T12, and no significant flicker sensitivity threshold improvement over the 10 repeat runs. T8 was superior to T12 on several other measures, so it was used for the remaining comparisons. In terms of diagnostic accuracy, the mean AUROC for the three tests were A4FTp [T8 criterion; 0.82, 95% confidence interval (0.73–0.92)]; SD‐OCT [any RNFL parameter p < 1% level; 0.90 (0.83–0.97)]; and FDT [one or more locations missed at p < 5% level; 0.91 (0.82–0.96)]. There was no statistical difference in AUROC between A4FTp and SD‐OCT (p = 0.18) or FDT (p = 0.12). The A4FTp test duration averaged just over 2 min per eye, taking approximately one‐third of the time for completion of the HFA SITA 24‐2 algorithm (conducted as part of the reference examination) and twice the time for the suprathreshold FDT.
Conclusion
Test accuracy for the A4FTp was comparable to those of the FDT and SD‐OCT for the detection of COAG. Time taken to complete the A4FTp was relatively short and initial results are promising. With further refinement, the A4FTp could have a future role in glaucoma detection
Vulnerabilidade dos solos à erosão: estimativa da perda de solos na bacia hidrográfica do Rio Guapi-Macacu - RJ.
Este trabalho apresenta metodologias para estimativa de perda de solos na Bacia Hidrográfica do Rio Guapi-Macacu - RJ. Para a estimativa anual de perdas de solo foi utilizada a ferramenta InVest (Integrated Valuation of Environmental Services and Tradeoffs) através do módulo que desenvolve retenção de sedimentos. Esse módulo permite calcular a perda de solo média anual de cada parcela de terra, além de determinar o quanto de solo pode chegar a um determinado ponto de interesse. Para identificar a perda potencial de solo, o modelo emprega a Equação Universal de Perda de Solo (USLE) na escala do pixel, integrando informações sobre relevo, precipitação, padrões de uso da terra e propriedades do solo. Seus resultados são dados em toneladas por sub-bacias. Os resultados obtidos neste trabalho permitiram concluir que embora haja limitações no uso da Equação Universal de Perda de Solo, o modelo possibilitou a espacialização de classes de perdas de solos com indicações de áreas consideradas mais ou menos vulneráveis aos processos erosivos, considerando os dados disponíveis e suas escalas. O uso do InVest para calcular a USLE apresentou como principal vantagem a possibilidade de integração dos dados necessários em um único ambiente, reduzindo a possibilidade de erros na conversão de dados. Contudo, a maior limitação encontrada a sua aplicação está na dificuldade de obtenção de dados de entrada necessários ao modelo.bitstream/item/129097/1/BPD-237-Vulnerabilidade-Solos.pd
Estimativa da perda de solos por meio da equação universal de perdas de solos (USLE) com uso do invest para a bacia hidrográfica do Rio Guapi-Macacu.
Este trabalho apresenta metodologia para estimativa de perda de solos na bacia hidrográfica do rio Guapi-Macacu ? RJ, a partir do módulo de estimativa de retenção de sedimentos da ferramenta InVest (Integrated Valuation of Environmental Services and Tradeoffs). Para identificar a perda potencial de solo, o módulo emprega a Equação Universal de Perdas de Solo (USLE), integrando informações sobre relevo, precipitação, padrões de uso da terra e propriedades do solo. Os resultados obtidos permitiram concluir que embora haja limitações no uso da Equação Universal de Perda de Solo, o modelo possibilitou a espacialização de classes de perdas de solos com indicações de áreas consideradas mais ou menos vulneráveis aos processos erosivos, considerando os dados disponíveis e suas escalas. O uso do InVest para calcular a USLE apresentou como principal vantagem a possibilidade de integração dos dados necessários em um único ambiente, reduzindo a possibilidade de erros na conversão de dados. Contudo, a maior limitação encontrada a sua aplicação esta na dificuldade de obtenção de dados de entrada necessários ao model
Construction of MV - and SMV - optimum designs for binary response models.
Recently, Dette and Sahm (1998) have put forward a procedure to construct MV-and SMV-optimurn designs for binary response models. In order to implement computationally this procedure some assumptions have to be made and some theoretical results must be proved. This paper provides the background to produce a computer code for computing local designs for different regions of the parameters of the model. Designs for some models used in practice are also provided as well as the efficiencies for estima the parameters
Comparative study on the potential of agritourism in two Brazilian municipalities.
The knowledge acquired by studying different aspects that can influence agritourism provide for adequate guidelines to carry out this rural activity, leading to greater sustainability and higher chances of success. This study was developed to identify the more important aspects that can improve or limit agritourism and, accordingly, analyse the potential and the limitations for agritourism development in two municipalities of Southeast Brazil. The municipalities are Venda Nova do Imigrante in the state of Espírito Santo, where the agritourism is successfully consolidated and Cachoeiras de Macacu in Rio de Janeiro state, where it is not very significant. This comparison was based on secondary and primary data - the latter were collected during field trips in these municipalities and by getting in touch with representatives of institutions and other local stakeholders. The results showed that the main similarities between the municipalities, which promote agritourism, are environmental, historic and cultural aspects; the presence of family farming with diversified production; and small rural industries. The main differences are the aspects related to land use, tourism management and agritourism infrastructure. An aspect that limits the activity in both municipalities is the lack of specific norms and legislation to guide and organize agritourism
Caracterização climática do Município de São José de Ubá, Estado do Rio de Janeiro.
bitstream/CNPS-2010/14921/1/bpd95-2006-clima-sao-jose-uba.pd
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