66 resultados para Glandulas mamarias


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Ciências Biológicas (Zoologia) - IBRC

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Human salivary gland tumors originated from intercalated ducts present a broad range of histologic and cytologic patterns, mainly due to the presence of myoepithelial cells. The aim of this study is to verify the differentiation grade of neoplastic cells and a possible relation between myoepithelial cell differentiation and the presence of luminal secretory contents. The expression of vimentin and cytokeratin (CK) intermediate filaments, actin myofilament and epithelial membrane antigen (EMA) was investigated by double labeling immunocytochemical technique, in thirty salivary gland neoplasms: 5 pleomorphic adenomas, 5 myoepitheliomas, 3 basal cell adenomas, 7 adenoid cystic carcinomas (ACC) and 10 polimorphous low grade adenocarcinomas (PLGA). Tumors with intercalated duct differentiation (pleomorphic adenomas, basal cell adenomas and ACC) express CKs 7, 8, 18 and 19 in the luminal cells and coexpress eventually CK14 with these CKs. Some luminal cells stained with anti-EMA antibody, mainly where a secretory content in the lumen was observed. Outer ductal cells and other myoepithelial-like cells express vimentin, sometimes coexpressing actin and/or CK14 with vimentin. Plasmacytoid cells in myoepitheliomas and pleomorphic adenomas express vimentin and rarely CKs 7, 8, 18 and 19, sometimes coexpressing these CKs with CK14 but they are negative for the remaining antigens. Tumors without intercalated duct differentiation (solid basal cell adenoma and PLGA) express vimentin and CKs 7, 8, 14 and 18, sometimes coexpressing CKs 8 and 18 with CK14. In conclusion, in tumors with intercalated duct differentiation, myoepithelial cells express vimentin and sometimes coexpress actin and/or CK14 with vimentin, never coexpressing other CKs with vimentin. CK14 and actin are independently expressed by myoepithelial cells, so their expression is probably induced by different stimulus. However, the secretory function of luminal cells, visualized by EMA staining, ....

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Devido à grande importância médico-veterinária dos carrapatos e a ampla utilização de produtos químicos sintéticos para o seu controle, tais como a permetrina, o presente estudo trouxe uma análise morfofisiológica, citoquímica e da reorganização do citoesqueleto durante os processos de degeneração e de morte celular que ocorreram nas glândulas salivares de fêmeas semi-ingurgitadas de carrapatos Rhipicephalus sanguineus quando expostas a 206, 1031 e 2062 ppm de permetrina. Os resultados obtidos mostraram que a permetrina é um potente agente químico que interfere na morfofisiologia do tecido glandular desta espécie, causando severas alterações na forma dos ácinos, bem como intensa vacuolização citoplasmática nas células acinares e acentuada desorganização do tecido glandular, culminando num avançado processo de degeneração, com consequente formação de corpos apoptóticos. Além disso, este piretróide comprometeu a capacidade de secreção das glândulas salivares, visto a drástica redução de proteínas, lipídeos e polissacarídeos nas diferentes células acinares. O material genético do tecido glandular também mostrou severas alterações induzidas pela permetrina, tais como: na forma e no tamanho do núcleo das células acinares, marginalização da cromatina, fragmentação nuclear, bem como surgimento de núcleos picnóticos, principalmente quando aplicadas as maiores concentrações do produto. Com relação à reorganização do citoesqueleto, os resultados revelaram que a permetrina foi capaz de modificar o citoesqueleto das glândulas salivares de R. sanguineus por meio de um processo gradual de desintegração à medida que as concentrações do acaricida aumentaram. Nestas células glandulares, os processos de morte celular ocorreram num ritmo mais acelerado do que em condições naturais, nas quais esse processo dar-se-ia somente no final do ingurgitamento da fêmea. Como consequência da...

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Melatonin is an endoleamine that has anti-inflammatory, immunomodulating and antioxidants properties. But there is a contradiction between the antioxidant effects of melatonin and glutathione (GSH). Therefore, the main objective of this work was to study the effect of melatonin on the oxidation of GSH and the effect of GSH on the oxidation of melatonin by peroxyl radicals generated by thermolysis of 2,2 -Azobis(2- amino-propane)-dihydrochloride (AAPH). The influence of the reaction conditions and the identity of the products of oxidation were also studied. The main products obtained during the oxidation of melatonin were its monohydroxylated derivative and N1-acetyl- N2-formyl-5-methoxykynuramine (AFMK), which is the product obtained by oxidative cleavage of the melatonin indole ring. By studying the buffer type, pH and the presence or absence of dissolved oxygen in the reaction system, it was observed that, the yield of AFMK was higher when the pH or the concentration of oxygen was increased. Comparing the reactivity of both molecules GSH and melatonin, it can be seen that intermediates radicals generated during the oxidation of melatonin are able to oxidize GSH itself. We propose that this chemical property could justify the recent reports that demonstrated the inability of melatonin to inhibit the oxidation of GSH in cells

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Pós-graduação em Cirurgia Veterinária - FCAV

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Medicina Veterinária - FCAV

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Serán objetivos de este programa: a) Alcanzar para la población el nivel más elevado de salud sexual y procreación responsable con el fin de que pueda adoptar decisiones libres de discriminación, coacciones o violencia; b) Disminuir la morbimortalidad materno-infantil; c) Prevenir embarazos no deseados; d) Promover la salud sexual de los adolescentes; e) Contribuir a la prevención y detección precoz de enfermedades de transmisión sexual, de vih/sida y patologías genital y mamarias; f) Garantizar a toda la población el acceso a la información, orientación, métodos y prestaciones de servicios referidos a la salud sexual y procreación responsable; g) Potenciar la participación femenina en la toma de decisiones relativas a su salud sexual y procreación responsable.

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A nivel mundial, el cáncer de mama es el tipo de cáncer más frecuente además de una de las principales causas de muerte entre la población femenina. Actualmente, el método más eficaz para detectar lesiones mamarias en una etapa temprana es la mamografía. Ésta contribuye decisivamente al diagnóstico precoz de esta enfermedad que, si se detecta a tiempo, tiene una probabilidad de curación muy alta. Uno de los principales y más frecuentes hallazgos en una mamografía, son las microcalcificaciones, las cuales son consideradas como un indicador importante de cáncer de mama. En el momento de analizar las mamografías, factores como la capacidad de visualización, la fatiga o la experiencia profesional del especialista radiólogo hacen que el riesgo de omitir ciertas lesiones presentes se vea incrementado. Para disminuir dicho riesgo es importante contar con diferentes alternativas como por ejemplo, una segunda opinión por otro especialista o un doble análisis por el mismo. En la primera opción se eleva el coste y en ambas se prolonga el tiempo del diagnóstico. Esto supone una gran motivación para el desarrollo de sistemas de apoyo o asistencia en la toma de decisiones. En este trabajo de tesis se propone, se desarrolla y se justifica un sistema capaz de detectar microcalcificaciones en regiones de interés extraídas de mamografías digitalizadas, para contribuir a la detección temprana del cáncer demama. Dicho sistema estará basado en técnicas de procesamiento de imagen digital, de reconocimiento de patrones y de inteligencia artificial. Para su desarrollo, se tienen en cuenta las siguientes consideraciones: 1. Con el objetivo de entrenar y probar el sistema propuesto, se creará una base de datos de imágenes, las cuales pertenecen a regiones de interés extraídas de mamografías digitalizadas. 2. Se propone la aplicación de la transformada Top-Hat, una técnica de procesamiento digital de imagen basada en operaciones de morfología matemática. La finalidad de aplicar esta técnica es la de mejorar el contraste entre las microcalcificaciones y el tejido presente en la imagen. 3. Se propone un algoritmo novel llamado sub-segmentación, el cual está basado en técnicas de reconocimiento de patrones aplicando un algoritmo de agrupamiento no supervisado, el PFCM (Possibilistic Fuzzy c-Means). El objetivo es encontrar las regiones correspondientes a las microcalcificaciones y diferenciarlas del tejido sano. Además, con la finalidad de mostrar las ventajas y desventajas del algoritmo propuesto, éste es comparado con dos algoritmos del mismo tipo: el k-means y el FCM (Fuzzy c-Means). Por otro lado, es importante destacar que en este trabajo por primera vez la sub-segmentación es utilizada para detectar regiones pertenecientes a microcalcificaciones en imágenes de mamografía. 4. Finalmente, se propone el uso de un clasificador basado en una red neuronal artificial, específicamente un MLP (Multi-layer Perceptron). El propósito del clasificador es discriminar de manera binaria los patrones creados a partir de la intensidad de niveles de gris de la imagen original. Dicha clasificación distingue entre microcalcificación y tejido sano. ABSTRACT Breast cancer is one of the leading causes of women mortality in the world and its early detection continues being a key piece to improve the prognosis and survival. Currently, the most reliable and practical method for early detection of breast cancer is mammography.The presence of microcalcifications has been considered as a very important indicator ofmalignant types of breast cancer and its detection and classification are important to prevent and treat the disease. However, the detection and classification of microcalcifications continue being a hard work due to that, in mammograms there is a poor contrast between microcalcifications and the tissue around them. Factors such as visualization, tiredness or insufficient experience of the specialist increase the risk of omit some present lesions. To reduce this risk, is important to have alternatives such as a second opinion or a double analysis for the same specialist. In the first option, the cost increases and diagnosis time also increases for both of them. This is the reason why there is a great motivation for development of help systems or assistance in the decision making process. This work presents, develops and justifies a system for the detection of microcalcifications in regions of interest extracted fromdigitizedmammographies to contribute to the early detection of breast cancer. This systemis based on image processing techniques, pattern recognition and artificial intelligence. For system development the following features are considered: With the aim of training and testing the system, an images database is created, belonging to a region of interest extracted from digitized mammograms. The application of the top-hat transformis proposed. This image processing technique is based on mathematical morphology operations. The aim of this technique is to improve the contrast betweenmicrocalcifications and tissue present in the image. A novel algorithm called sub-segmentation is proposed. The sub-segmentation is based on pattern recognition techniques applying a non-supervised clustering algorithm known as Possibilistic Fuzzy c-Means (PFCM). The aim is to find regions corresponding to the microcalcifications and distinguish them from the healthy tissue. Furthermore,with the aim of showing themain advantages and disadvantages this is compared with two algorithms of same type: the k-means and the fuzzy c-means (FCM). On the other hand, it is important to highlight in this work for the first time the sub-segmentation is used for microcalcifications detection. Finally, a classifier based on an artificial neural network such as Multi-layer Perceptron is used. The purpose of this classifier is to discriminate froma binary perspective the patterns built from gray level intensity of the original image. This classification distinguishes between microcalcifications and healthy tissue.