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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Quantitative characterization and modeling of the microstructure of solid oxide fuel cell composite electrodes

Zhang, Shenjia 23 August 2010 (has links)
Three-phase porous composites containing electrolyte (ionic conductor), electronic conductor, and porosity phases are frequently used for solid oxide fuel cell (SOFC) electrodes. Performance of such electrodes is microstructure sensitive. Topological connectivity of the microstructural phases and total length of triple phase boundaries are the key microstructural parameters that affect the electrode performance. These microstructural attributes in turn depend on numerous process parameters including relative proportion, mean sizes, size distributions, and morphologies of the electrolyte and electronic conductor particles in the powder mix used for fabrication of the composites. Therefore, improvement of the performance of SOFC composite electrodes via microstructural engineering is a complex multivariate problem that requires considerable input from microstructure modeling and simulations. This dissertation presents a new approach for geometric modeling and simulation of three-dimensional (3D) microstructure of three-phase porous composites for SOFC electrodes and provides electrode performance optimization guidelines based on the parametric studies on the effects of processing parameters on the total length and topological connectivity of the triple phase boundaries. The model yields an equation for total triple phase boundary length per unit volume (LTPB) that explicitly captures the dependence of LTPB on relative proportion of electrolyte and electronic conductor phases; volume fraction of porosity; and mean size, coefficient of variation, and skewness of electrolyte and electronic conductor particle populations in the initial powder mix. The equation is applicable to electrolyte and electronic conductor particles of any convex shapes and size distributions. The model is validated using experimental measurements performed in this research as well as the measurements performed by other researchers. Computer simulations of 3D composite electrode microstructures have been performed to further validate the microstructure model and to study topological connectivity of the triple phase boundaries in 3D microstructural space. A detailed parametric analysis reveals that (1) non-equiaxed plate-like, flake-like, and needle-like electrolyte and electronic conductor particle shapes can yield substantially higher LTPB; (2) mono-sized electrolyte and electronic conductor powders lead to higher LTPB as compared to the powders having size distributions with large coefficients of variation; (3) LTPB is inversely proportional to the mean sizes of electrolyte and electronic conductor particles; (4) a high value of LTPB is obtained at the lowest porosity volume fraction that permits sufficient connectivity of the pores for gas permeability; and (5) LTPB is not sensitive to the relative proportion of electrolyte and electronic conductor phases in the composition regime of interest in composite electrode applications.
122

Effets de l’alcoolisme fœtal sur le développement du corps genouillé latéral du singe

Papia, Marc 11 1900 (has links)
L’exposition du fœtus à l’éthanol est reconnue comme étant la principale cause de maladies évitables lors du développement. Une forte exposition à l’alcool durant la gestation peut occasionner des dysmorphies cranio-faciales et des retards mentaux, ainsi que des troubles d’apprentissages et du comportement. Le développement du système visuel est également perturbé chez une grande majorité d’enfants qui ont été exposés à l’alcool. Lorsque les doses prises sont élevées, le système visuel peut présenter une panoplie de symptômes comme une augmentation de la tortuosité des vaisseaux rétiniens, de la myopie, de l’hypermétropie, du strabisme et une hypoplasie du nerf optique. Cependant, très peu d’études se sont penchées sur les effets de plus faibles doses sur le développement du système visuel du primate. Le singe est un excellent modèle pour étudier le système visuel car il possède plusieurs similitudes avec l’humain tant au niveau développemental qu’au niveau structurel. De plus, le singe utilisé, le Chlrocebus aethiops sabeus, possède l’avantage que des individus de cette espèce ont une consommation naturelle et volontaire à l’alcool. Une étude (Clarren et al., 1990) a suggéré qu’une faible exposition à l’alcool du fœtus du primate non humain occasionnait une diminution du nombre de cellules ganglionnaires de la rétine (CGRs). Étant donné que le corps genouillé latéral dorsal (CGLd) reçoit la plupart de ses intrants de la rétine, il est raisonnable d’assumer que les couches rétino-récipientes du CGLd devraient être aussi affectées. Nous avons alors émis l’hypothèse que le CGLd devrait également subir une diminution du nombre de neurones. Pour la première fois, nous avons utilisé une méthode stéréologique pour quantifier le nombre de cellules dans les couches parvo- (P) et magnocellulaires (M) du CGLd. Contrairement à notre hypothèse de départ, nous n’avons pas observé de diminution dans le nombre global de neurones dans le CGLd des animaux exposés à l’alcool par rapport à des sujets contrôles, ni une diminution de son volume. Nous avons toutefois observé une diminution de la taille du corps cellulaire seulement dans la population M du CGLd. Ces résultats suggèrent que le système visuel est affecté par une faible exposition à l’alcool durant son développement qui devrait se traduire sur le comportement par des déficits dans les fonctions de la voie M. / An alcohol exposition during the gestation is recognized as the leading causes of preventable developmental disorders. A heavy exposure to ethanol can lead to a litany of symptoms ranging from cranio-facial dysmorphology and mental retardation to developmental learning and behavioural disorders. The visual system development is also the target for a high percentage of children exposed prenatally to alcohol. When the concentrations are relatively high, the visual system can show signs of increased tortuosity of the retina vessels, myopia, hyperopia, strabismus and hypoplasia of the optic nerve. Few studies have examined the effects of a moderate exposure to alcohol on the development of the primate visual system. The monkey is an excellent model to study the visual system because this model owns a lot of similarities with human at the developmental and structural levels. Moreover, the monkey used for this study, Chlrocebus sabeus, naturally and voluntarily consumes alcohol. One study (Clarren et al., 1990) suggested that a low dose exposure of alcohol induce a diminution of neurons in the ganglion retinal cell population. But, no information is given about the numbers and the cell population of neurons. We hypothesized that the lateral geniculate nucleus (LGN) should show a decrease in the number of neurons after moderate prenatal exposure to alcohol. The LGN is a key region because it is situated between the region that receives visual information, the retina, and the first visual region that analyzes the visual information, the primary visual cortex (V1). We utilized a stereological method to study the effects of moderate doses of alcohol on the neuronal population of the LGN in the non-human primate. In opposition to our hypothesis, we have not observed any diminution in the number of neurons or the volume of the LGN. However, we have found a diminution in the neuronal volume of only the magnocellular (M) region. These results suggest that the visual system is affected by a low dose of alcohol that should translate into deficits in the functions of the M pathway.
123

Impact of glucocorticoids on placental growth and vascularisation

Hewitt, Damien Phillip January 2007 (has links)
[Truncated abstract] Glucocorticoids are critical for the maturation of the fetus late in pregnancy. Indeed, clinical administration of glucocorticoids is used to accelerate fetal lung maturation in mothers at risk of pre-term delivery. Increased glucocorticoid exposure, however, can have detrimental effects on fetal and placental growth and increase the risk of disease in later life. Many studies have focused on the effect of an increase in the transplacental passage of glucocorticoids on both fetal growth and subsequent postnatal development. But there is a growing body of evidence to suggest that the impact of glucocorticoids on fetal growth is mediated, in part, via their direct effects on the placenta . . . Overall, these studies quantify the labyrinth zone-specific increases in placental expression of PPARG and VEGF in association with a marked increase in vascularisation observed near term. Furthermore, this study demonstrates for the first time that these increases in gene expression are prevented by maternal dexamethasone treatment which also inhibits growth of the fetal capillary network. Elevated expression of SFRP4 in the regressing basal zone late in gestation and in both placental zones after dexamethasone-induced placental growth restriction is consistent with a role for SFRP4 in glucocorticoid-mediated inhibition of wnt signalling. Collectively, the data presented in this thesis show that glucocorticoid inhibition of fetal growth is mediated in large part via effects on the placenta, specifically through inhibition of signals that promote proliferation and vascularisation.
124

Implementa??o da rotina de unfolding para determina??o de distribui??o de tamanho de gr?os esf?ricos via distribui??o de interceptos lineares e de ?rea de se??o

Ferreira Filho, Antonio Evangelista 26 February 2009 (has links)
Made available in DSpace on 2014-12-17T14:06:51Z (GMT). No. of bitstreams: 1 AntonioEFF.pdf: 720128 bytes, checksum: febce55b295b3d3be15f1c24bf498884 (MD5) Previous issue date: 2009-02-26 / Na unfolding method of linear intercept distributions and secction ?rea distribution was implemented for structures with spherical grains. Although the unfolding routine depends on the grain shape, structures with spheroidal grains can also be treated by this routine. Grains of non-spheroidal shape can be treated only as approximation. A software was developed with two parts. The first part calculates the probability matrix. The second part uses this matrix and minimizes the chi-square. The results are presented with any number of size classes as required. The probability matrix was determined by means of the linear intercept and section area distributions created by computer simulation. Using curve fittings the probability matrix for spheres of any sizes could be determined. Two kinds of tests were carried out to prove the efficiency of the Technique. The theoretical tests represent ideal cases. The software was able to exactly find the proposed grain size distribution. In the second test, a structure was simulated in computer and images of its slices were used to produce the corresponding linear intercept the section area distributions. These distributions were then unfolded. This test simulates better reality. The results show deviations from the real size distribution. This deviations are caused by statistic fluctuation. The unfolding of the linear intercept distribution works perfectly, but the unfolding of section area distribution does not work due to a failure in the chi-square minimization. The minimization method uses a matrix inversion routine. The matrix generated by this procedure cannot be inverted. Other minimization method must be used / A rotina de desdobramento (unfolding) de distribui??es de intercepto linear e de ?rea de se??o foi implementada para gr?os de formato esf?rico. Apesar da rotina de unfolding ser fortemente dependente do formato do gr?o, estruturas que possuam gr?os com formatos esferoidais podem ser tratadas com esta rotina. Mesmo estruturas com gr?os de formatos n?o esferoidais podem ser tratadas por aproxima??o. Um programa com duas partes foi desenvolvido. Primeira parte determina a tabela de probabilidades. A segunda utiliza esta tabela e aplica o m?todo de minimiza??o do chi-quadrado. Os resultados s?o dados em qualquer n?mero de classes de tamanho de gr?o requerido pelo usu?rio. A tabela de probabilidade foi determinada a partir de distribui??es de intercepto linear e de ?rea de se??o geradas por simula??o computacional. Por meio de ajustes de curvas de distribui??o, tabelas de probabilidades para esferas de qualquer tamanho podem ser determinadas. Dois tipos de testes foram executados para verificar a efici?ncia do m?todo. Os testes te?ricos representam situa??es ideais. O programa conseguiu reproduzir com exatid?o as distribui??es de tamanho de gr?o sugeridas. Os testes simulados consistem em simular em computador distribui??es de tamanho de gr?os e executar todo o procedimento metalogr?fico usual. Este tipo de teste ? mais pr?ximo da situa??o real. Os resultados deste tipo de teste mostram que a rotina de medi??o estereol?gica introduz desvios estat?sticos, afastando o resultado encontrado do valor real. Contudo, a rotina de unfolding funciona perfeitamente para a distribui??o de intercepto linear. No caso de unfolding de ?rea de se??o, a minimiza??o do chi-quadrado pelo m?todo matricial gera matrizes n?o invers?veis e n?o pode ser aplicada. Outro m?todo de minimiza??o deve ser buscado
125

Simula??o computacional de medidas estereol?gicas em estruturas de metal duro (WC-Co)

Esteves, Ezequias Matos 22 August 2011 (has links)
Made available in DSpace on 2014-12-17T14:07:08Z (GMT). No. of bitstreams: 1 EzequiasME_TESE.pdf: 4077046 bytes, checksum: 10fbafe209b02444fb805640364b456c (MD5) Previous issue date: 2011-08-22 / This work focuses on the creation and applications of a dynamic simulation software in order to study the hard metal structure (WC-Co). The technological ground used to increase the GPU hardware capacity was Geforce 9600 GT along with the PhysX chip created to make games more realistic. The software simulates the three-dimensional carbide structure to the shape of a cubic box where tungsten carbide (WC) are modeled as triangular prisms and truncated triangular prisms. The program was proven effective regarding checking testes, ranging from calculations of parameter measures such as the capacity to increase the number of particles simulated dynamically. It was possible to make an investigation of both the mean parameters and distributions stereological parameters used to characterize the carbide structure through cutting plans. Grounded on the cutting plans concerning the analyzed structures, we have investigated the linear intercepts, the intercepts to the area, and the perimeter section of the intercepted grains as well as the binder phase to the structure by calculating the mean value and distribution of the free path. As literature shows almost consensually that the distribution of the linear intercepts is lognormal, this suggests that the grain distribution is also lognormal. Thus, a routine was developed regarding the program which made possible a more detailed research on this issue. We have observed that it is possible, under certain values for the parameters which define the shape and size of the Prismatic grain to find out the distribution to the linear intercepts that approach the lognormal shape. Regarding a number of developed simulations, we have observed that the distribution curves of the linear and area intercepts as well as the perimeter section are consistent with studies on static computer simulation to these parameters. / Este trabalho versa sobre a cria??o e as aplica??es de um software de simula??o din?mica para estudo da estrutura do metal duro (WC-Co). A base tecnol?gica utilizada para amplia??o da capacidade de hardware foi a GPU Geforce 9600 GT com o chip Physx criada com o prop?sito de dar mais realismo aos jogos eletr?nicos. O software simula a estrutura tridimensional do metal duro com o formato de uma caixa c?bica onde os carbetos de tungst?nio (WC) s?o modelados como prismas triangulares e prismas triangulares truncados. O programa se mostrou eficiente em testes de verifica??o, desde c?lculos de medidas de par?metros como na capacidade de amplia??o do n?mero de part?culas simuladas dinamicamente. Foi poss?vel fazer uma investiga??o de par?metros m?dios e de distribui??es de par?metros estereol?gicos utilizados para caracterizar a estrutura do metal duro atrav?s de planos de cortes. Nos planos de cortes das estruturas analisadas foram investigados os interceptos lineares, intercepto de ?rea e per?metro de se??o dos gr?os interceptados e a fase ligante da estrutura atrav?s do c?lculo do valor m?dio e da distribui??o do livre caminho. Como a literatura ? quase consensual que a distribui??o dos interceptos lineares ? lognormal e que isso sugere que a distribui??o dos gr?os na estrutura tamb?m seja lognormal, foi desenvolvida uma rotina no programa, que possibilitou uma investiga??o mais detalhada dessa quest?o. Foi observado que ? poss?vel, sob certos valores para os par?metros que definem o formato e tamanho do gr?o prism?tico, encontrar distribui??o de interceptos lineares que se aproximam do formato lognormal. Nas v?rias simula??es desenvolvidas foi verificado que as curvas de distribui??es de interceptos lineares, de ?rea e per?metro de se??o, est?o de acordo com trabalhos na literatura de simula??o computacional est?tica desses par?metros.
126

Estudo morfológico do hipocampo de uma espécie de primata da Amazônia: Cebus apella, (Linnaeus, 1758) / Anatomic study of the hippocampus in a primate species of the Amazon Cebus apella (Linnaeus, 1812)

Torres, Laila Brito [UNIFESP] 24 November 2010 (has links) (PDF)
Made available in DSpace on 2015-07-22T20:50:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-11-24 / Os primatas constituem modelos animais insubstituíveis para áreas de investigação científica devido a sua estreita relação evolutiva com os seres humanos o que assegura modelos de alta fidelidade com capacidade preditiva e discriminativa que podem não estar disponíveis em outras espécies. O Cebus apella, uma espécie de primata do novo mundo que pertence à família Cebidae, subordem Cebinae (Linnaeus, 1758), são comumente usados em pesquisas biomédicas e comportamental sendo uma espécie eleita para muitos modelos experimentais com enfoque cognitivo. O hipocampo, estrutura límbica altamente plástica situado no lóbulo temporal é importante para a aprendizagem e consolidação da memória. Desta forma, o objetivo deste estudo foi caracterizar quantitativamente e qualitativamente as células parvalbumina-positivas no hipocampo de Cebus apella, bem como estimar o volume e o número de neurônios em seus diferentes subcampos, utilizando o método do fracionador óptico. Os resultados obtidos em nosso estudo podem ser úteis para diversos projetos experimentais que tenham como foco a medicina translacional. / The nonhuman primates constitute irreplaceable animal models for research areas in which their close evolutionary relationship to humans ensures high fidelity models with predictive and discriminative abilities that may not be available in other species. The Cebus apella, a New World primate specie belonging to the Cebidae family, Cebinae suborder (Linnaeus, 1758) are commonly used in biomedical and behavior research being the specie of choice for many cognitive experimental tasks. The hippocampus, a highly plastic limbic structure situated in the temporal lobe is important for learning and memory consolidation. In this way, the aim of this study was to characterize quantitatively and qualitatively the Parvalbumin positive cells in the hippocampal formation of the Cebus monkey and also estimate the volume and neuronal number in their different subfields using an optical fractionator design method. The results obtained in our study will be useful for many experimental designs in translational medicine. / TEDE / BV UNIFESP: Teses e dissertações
127

Estereologia, imuno-histoquímica e microscopia eletrônica de varredura na análise da reação tecidual a implantes de discos de adesivo dentinário fotoativado, hidróxido de cálcio e cimento de ionômero de vidro: estudo experimental em ratos / Stereology, imunohistochemistry, and scanning electron microscopy in the analysis of tissue reaction to disks implants of light-cured dentin adhesive, calcium hydroxide, and glass ionomer cement: experimental study in rats

Rogério Luiz de Oliveira Mussel 17 May 2002 (has links)
Objetivo: avaliar a biocompatibilidade de materiais indicados como protetores pulpar no tecido subcutâneo de ratos ao longo do tempo. Métodos: Implantes padronizados de Hidróxido de Cálcio (HC), Cimento de Ionômero de Vidro (CIV) e Adesivo Dentinário Fotoativado (ADF) foram colocados cirurgicamente no dorso de ratos Wistar e deixados por 15 e 30 dias (cada grupo com 5 animais) e os respectivos grupos sham (S). Após a experimentação os animais foram sacrificados e material do dorso dos animais foi retirado para estudo ao microscópio de luz com estereologia e imuno-histoquímica para &#945;-actina de músculo liso (ACML, detecção de miofibroblastos). As pastilhas e a superfície das cápsulas fibrosas foram analisadas quanto a textura, em microscopia eletrônica de varredura (MEV) com microanálise. Resultados: Houve diferenças na fibrose e no número de mastócitos na região peri-implante dependente do tipo de implante. Não foram detectados miofibroblastos expressando ACML. O menor valor de densidade volumétrica de fibrose intersticial (Vv[f]) ocorreu no grupo HC, e o maior no grupo ADF (diferença significativa em relação ao grupo S, nos dois tempos experimentais, p<0,05). Entretanto, aos 30 dias, houve acréscimo de 30% de Vv[f] do grupo ADF, determinando, neste período, diferença significativa em relação ao grupo HC. Quanto a densidade numérica de mastócitos por área (NA[mastócito]) o menor valor ocorreu no grupo HC sem diferença para o grupo S, mas diferença para o grupo ADF (este com o maior valor de NA[mastócito] nos dois tempos experimentais). O grupo CIV apresentou, para Vv[f] e NA[mastócito], durante toda a experimentação, resultados intermediários aos grupos HC e ADF. Houve fibrose discreta e restrita a área cirúrgica com poucos mastócitos juntos aos vasos no grupo S. Houve correlação positiva para Vv[f] e NA[mastócito], no grupo ADF. Ao MEV viu-se interação, no grupo HC, entre o material da pastilha e sua cápsula fibrótica, mas não nos grupos ADF e CIV. Conclusão: Os materiais estudados induziram a formação de fibrose e migração de mastócitos de modo diferenciado. Os resultados sugerem o HC como o material mais compatível biologicamente dentre os testados neste trabalho. / Purpose: to evaluate the biocompatibility of some pulpar protecting materials in the subcutaneous tissue of rats along the time. Methods: standardized implants of Calcium Hydroxide (CH), Glass Ionomer Cement (GIC) and Light-cured Dentin Adhesive (LDA) surgically were put in the back of Wistar rats and left by 15 and 30 days (each group with 5 animals) and the respective sham groups (S). After the experimentation the animals were sacrificed and material from the back of the animals was removed for study with light microscope, stereology and immunohistochemistry for smooth muscle alfa-actin (SMAA, myofibroblast detection). The implants and the fibrous capsule surfaces were analyzed with the scanning electronic microscopy (SEM) adapted with microanalysis. Results: the fibrosis and the number of mastocytes were different in the implant area depending of the implant type. Myofibroblasts were not detected expressing SMAA. The smallest value of the volume density of interstitial fibrosis (Vv[f]) occured in the CH group, and the largest in the LDA group (the difference was significant in relation to the S group, in the two experimental times, p < 0.05). However, to the 30 days, the Vv[f] of the LDA group increase 30%, being different from the CH group in this period. The numerical density of mastocytes per area (NA[mastocyte]) was smaller in the CH group without difference for the S group, but with difference from the LDA group (this group had the largest NA[mastocyte] value in the two experimental times). The GIC group had, for Vv[f] and NA[mastocyte] all experimentation time, intermediary values ranging from CH to LDA values. There was discreet and restricted fibrosis in the surgical area with few mastocytes associated to vessels in the S group. There was positive correlation for Vv[f] and NA[mastocyte] in the LDA group. In the CH group the SEM observed interaction between the implant material and its fibrotic capsule, but not in the LDA and GIC groups. Conclusion: The studied materials induced the fibrosis formation and mastocytes migration in a differentiated way. The results suggest that CH as the most biologically compatible material among the materials tested in this work.
128

Análise estrutural do corpo cavernoso de pacientes com priapismo isquêmico / Structural analysis of the corpus cavernosum of patients with ischemic priapism

Bruno Félix Patrício 25 February 2009 (has links)
O objetivo do presente trabalho é avaliar através de métodos quantitativos e qualitativos, as alterações nos corpos cavernosos de indivíduos com priapismo isquêmico. Foram estudados fragmentos de corpos cavernosos obtidos por biópsia de sete pacientes com, pelo menos, 48 horas de priapismo isquêmico, com idade entre 27 e 44 anos (média de 38 anos). Os pacientes foram submetidos a tratamento cirúrgico pela técnica de Al-ghorab. O material foi submetido a técnicas histoquímicas e imunohistoquímicas para a caracterização e quantificação do músculo liso e dos elementos fibrosos do tecido conjuntivo. A análise do corpo cavernoso dos pacientes com priapismo e do grupo controle, mostrou os seguintes resultados: Colágeno: controle = 34.76 4.64, priapismo = 39.64 2.91 (p = 0.0019); sistema elástico: controle 28.10 2.85, priapismo 36.10 3.06 (p = 0.0012) fibras musculares: controle = 43.37 4.96, priapismo = 26.48 5.00 (p < 0.0001). Ficou caracterizado aumento estatisticamente significativo dos elementos fibrosos do tecido conjuntivo e diminuição significativa nas fibras musculares lisas do corpo cavernoso dos pacientes com priapismo isquêmico. O presente estudo mostrou que o priapismo isquêmico está associado a alterações significativas nos componentes da matriz extracelular e na musculatura lisa do corpo cavernoso. Esses resultados poderiam explicar a disfunção erétil que acompanha os pacientes com priapismo isquêmico. / The purpose of the present study was to evaluate through quantitative and qualitative methods, the changes in the corpora cavernosa of patients with ischemic priapism. We obtained samples of corpora cavernosa from 7 patients with ischemic priapism, aged between 28 and 44 years (mean = 38), who underwent a cavernosal-glandular shunt. The control tissues were fragments of corpora cavernosa obtained from autopsies of 7 age-matched men who died of causes not related to the urogenital tract. Histochemical and immunohistochemical techniques were used to assess and quantify the extra-cellular matrix and smooth muscle fibers. The volumetric density of smooth muscle, elastic fibers and collagen were determined in corpora cavernosa. The stereological analysis showed the following values of volumetric density in the structures studied. Collagen: controls = 34.76 4.64, priapism = 39.64 2.91 (p = 0.0019); elastic system fibers: controls 28.10 2.85, priapism 36.10 3.06 (p = 0.0012), smooth muscle fibers: controls = 43.37 4.96, priapism = 26.48 5.00 (p < 0.0001). Our results demonstrated a significant increase in the fibrous elements of the connective tissue and a significant decrease of smooth muscle fibers in the corpora cavernosa of patients with ischemic priapism, when compared to controls. As conclusion, this study showed that ischemic priapism is associated with early significant changes in the components of the extra cellular matrix and smooth muscle fibers of corpora cavernosa. This could explain the frequent occurrence of erectile dysfunction found in patients with ischemic priapism.
129

Envolvimento cardíaco e pulmonar na esquistossomose aguda e crônica de camundongos alimentados com dieta hiperlipídica / Cardiac and pulmonary involvement on acute and chronic schistosomiasis in mice fed high-fat diet

Vanessa Coelho de Góes 14 March 2011 (has links)
Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / O objetivo desse trabalho foi avaliar as alterações no tecido cardíaco e pulmonar de camundongos dislipidêmicos, esquistossomóticos e seus controles que haviam sido eutanasiados com 9 (fase aguda) e 17 (fase crônica) semanas de infecção. Foram estudados quatro grupos de camundongos, segundo a dieta e tempo de infecção: dieta padrão (SCa e SCc), dieta hiperlipídica (HFCa e HFCc), dieta padrão infectados (ISCa e ISCc) e dieta hiperlipídica infectados (IHFCa e IHFCc). O coração e o pulmão foram retirados, seccionados e os fragmentos foram submetidos a processamento histológico e corados com Hematoxilina e Eosina e Picrosirius red. Foram realizadas análises histopatológicas dos dois órgãos, além de estudos estereológico (dissector óptico) e morfométrico (vasos, cardiomiócitos e quantificação de colágeno) do coração. Os grupos foram comparados pelos Testes T de Student e/ou ANOVA. Todos os animais com dieta hiperlipídica, infectados ou não, apresentaram menor densidade de número e número total de cardiomiócitos (p<0,05), além de vasos intramiocárdicos com lúmen mais reduzido e paredes mais espessas que os controles, independente da semana em que foram eutanasiados. Os cardiomiócitos dos grupos IHFCa e IHFCc estavam mais hiperplásicos (p<0,0001) e continham mais colágeno ao redor (p<0,05) que os dos demais grupos estudados. Os corações dos grupos IHFC, nas duas fases, apresentaram maior quantidade de nichos inflamatórios, inúmeras regiões contendo coagulação de fibras cardíacas, maior número de áreas com desaparecimento de fibras e proliferação de fibroblastos quando comparados aos grupos ISC. Os pulmões de camundongos do grupo IHFCc apresentaram aumento do número de reações granulomatosas e infiltrados perivasculares quando comparados aos demais grupos infectados. Esses dados sugerem que a infecção por S. mansoni causa danos às estruturas miocárdica e pulmonar que se intensificam com a interação com a dieta rica em lipídios. / The aim of this work was to evaluate changes in heart and lung tissue of mice underlying dyslipidemia, schistosomiasis and their controls euthanized in 9th (acute phase) and 17th (chronic phase) weeks post-infection. Four groups of mice were studied, according to the diet and time of infection: standard chow (SCa and SCc), high-fat chow (HFCa and HFCc), infected standard chow (ISCa and ISCc) and infected high-fat chow (IHFCa and IHFCc). The heart and lungs were extracted, sectioned and their fragments passed by histological procedures and were stained with Hematoxilin and Eosin and Picrosirius Red. Histopathological analysis was performed on both organs, and also stereological (optical disector) and morphometric studies (vessels, cardiomyocytes and quantification of collagen) of the heart. Groups were compared by: Student T and/or ANOVA tests. All animals fed high-fat chow, infected or not, had a lower numerical density and total number of cardiomyocytes (p<0.05), and also intramyocardial vessels with smaller lumens and thicker walls than controls, independent of the week that were euthanized. Cardiomyocytes of IHFCa and IHFCc groups were more hyperplastic (p<0.0001) and contained more collagen around (p<0.05) than those of all other groups. The hearts of the IHFC groups, in both phases, showed a higher number of inflammatory niches, several areas containing coagulation of cardiac fibers, a greater number of cardiomyocytes losses and proliferation of fibroblasts compared to ISC groups. Mice lungs of IHFCc group presented an increased number of reports of granulomatous reactions and perivascular infiltrates when compared to other infected groups. These data suggest that S. mansoni infection causes damages to myocardial and pulmonary structures which are intensified by high-fat diet association.
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Avaliação quantitativa e qualitativa das alterações no tecido esplênico de camundongos esquistossomóticos e dislipidêmicos / Quantitative and qualitative assessment of changes in splenic tissue of mice with schistossomiasis and dyslipidemic

Adriana Matias da Silva 27 April 2012 (has links)
Neste estudo, investigamos a organização qualitativa e quantitativa do tecido esplênico na fase aguda (nona semana) da infecção pelo Schistosoma mansoni em camundongos Swiss alimentados com uma dieta hipercolesterolêmica (29% lipídios) ou uma ração padrão (12% de lipídios). O volume do baço foi medido pelo método de Scherle. Os cortes histológicos (5m) foram corados com hematoxilina-eosina, Lennerts Giemsa e Picrosirius. O tecido foi avaliado por histopatologia, morfometria e estereologia. A análise estatística foi realizada utilizando-se o programa Graph Pad Instat. Nossos resultados demonstraram que tanto a dieta quanto a infecção determinam perturbações em compartimentos esplênicos. Camundongos infectados, independentemente da dieta, tiveram aumento do baço (P=0,004) e arquitetura esplênica desorganizada quando comparado aos não infectados. O compartimento de polpa branca foi reduzida, enquanto a polpa vermelha e centro germinativo foram aumentadas (P<0,01). Camundongos infectados alimentados com alto teor de gordura apresentaram maior diâmetro de polpa branca (P=0,013) do que os não infectados. O exame microscópico do baço de camundongos não infectados alimentados com ração hipercolesterolêmica indicou que a polpa branca foi reduzida e indistinta. Além disso, camundongos infectados mostraram infiltrados celulares caracterizados por células polimorfonucleares, com mitose linfocítica intensa e células de Mott. Hemossiderina tende a ser em menor grau em camundongos infectados em comparação com os controles não infectados. A polpa vermelha mostrou um aumento significativo (P=0,008) no número médio de megacariócitos em comparação com camundongos não infectados. Camundongos alimentados com dieta padrão mostraram granuloma exsudativo-produtivo em torno de ovos do S. mansoni distribuídas apenas escassamente na polpa vermelha, enquanto que uma resposta do tecido caracterizada por uma infiltração de células em camundongos alimentados com alto teor de gordura foi encontrado. Os resultados do estudo sugerem que a ingestão de dieta rica em gorduras e a infecção contribuíram para a desorganização esplênica

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