948 resultados para Reflective light microscopy


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

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A recently described non-viral gene delivery system [dioctadecyldimethylammonium bromide (DODAB)/monoolein (MO)] has been studied in detail to improve knowledge on the interactions between lamellar (DODAB) and non-lamellar-forming (MO) lipids, as a means to enhance their final cell transfection efficiency. Indeed, the morphology, fluidity, and size of these cationic surfactant/neutral lipid mixtures play an important role in the ability of these systems to complex nucleic acids. The different techniques used in this work, namely dynamic light scattering (DLS), fluorescence spectroscopy, differential scanning calorimetry (DSC), cryogenic transmission electron microscopy (cryo-TEM), light microscopy (LM), and surface pressure-area isotherms, allowed fully characterization of the phase behavior and aggregate morphology of DODAB/MO mixtures at different molar ratios. Overall, the results indicate that the final morphology of DODAB/MO aggregates depends on the balance between the tendency of DODAB to form zero-curvature bilayer structures and the propensity of MO to form non-bilayer structures with negative curvature. These results also show that in the MO-rich region, an increase in temperature has a similar effect on aggregate morphology as an increase in MO concentration. (C) 2012 Elsevier B.V. All rights reserved.

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Atualmente, muito se discute a respeito da natureza pré-maligna do líquen plano bucal. OBJETIVO: O presente trabalho tem como objetivo analisar as alterações das células epiteliais presentes no líquen plano bucal, comparando-as com aquelas observadas no carcinoma epidermóide. MATERIAL E MÉTODO: Cortes histológicos de líquen plano bucal e carcinoma epidermóide, corados com hematoxilina-eosina, foram analisados por meio da microscopia de luz. RESULTADO: As alterações mais frequentemente observadas no líquen plano bucal foram aumento da relação núcleo/citoplasma (93,33%), espessamento da membrana nuclear (86,67%) e bi-ou multinucleação (86,67%). O teste t de Student (alfa=5%) revelou haver diferença estatisticamente significante entre o número médio de alterações celulares no líquen plano bucal (5,87±1,57) e no carcinoma epidermóide (7,60±1,81). Quanto aos tipos de alterações, o teste de qui-quadrado também revelou haver diferença estatisticamente significante entre as lesões avaliadas em relação às seguintes alterações celulares: hipercromatismo nuclear, mitoses atípicas, pleomorfismo celular e diferenciação celular anormal (p<0,05). CONCLUSÃO: Apesar de que, em alguns casos, alguns patologistas possam fazer confusão no diagnóstico histopatológico do líquen plano bucal, os resultados obtidos neste estudo mostram que as alterações presentes no líquen plano bucal diferem consideravelmente daquelas observadas no carcinoma epidermóide, evidenciando o quão distintas são estas duas doenças.

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

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Purpose: The aim of this study was to evaluate the possibility of obtaining guided bone regeneration using a poly-tetrafluoroethylene (PTFE) nonporous barrier for 2 endosseous implants, partially inserted in tibiae of rabbits.Materials and Methods: Histologic characteristics of the interface between titanium implants (one group with titanium plasma-coated implants and the other group with acid-treated surfaces) and of the regenerated bone were also studied. Twenty screw-vent implants were placed in tibiae of 5 male New Zealand rabbits, 2 at the right side and 2 at the left side, protruding 3 mm from the bone level, to create a horizontal bone defect. At the experimental group the implants were with a PTFE nonporous barrier, whereas no barriers were used in contralateral implants. Animals were sacrificed 3 months after surgery and biopsy specimens were evaluated histologically and histomorphometrically under light microscopy. Student's t test was used for statistical analysis.Results: The histologic measurements showed a mean gain in bone height of 2.15 and 2.42 mm for the barrier group and 1.95 and 0.43 mm for the control group, for the titanium plasma-spray and acid-treated implant surfaces, respectively.Conclusion: The results of the investigation revealed that the placement of implants protruding 3 nun from crestal bone defects may result in vertical bone augmentation using a nonporous PTFE barrier. (Implant Dent 2009;18:182-191)

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As alterações morfológicas pulpares, decorrentes de um estímulo externo experimental (interferência oclusal), foram estudadas, em nível de microscopia de luz. Utilizaram-se restaurações de amálgama, em sobreoclusão nos primeiros molares superiores direitos de dez ratos Wistar, divididos em 3 grupos e sacrificados por perfusão transcardíaca com formol a 10%, aos 10, 20 e 30 dias. A avaliação foi feita nos molares inferiores direitos (lado experimental) e esquerdos (lado controle). As peças ósseas após descalcificação em solução de EDTA associada às microondas, seguiram técnica histológica de rotina e coloração por hematoxilina-eosina e tricrômico de Mallory. Verificou-se no lado controle uma reação intensa caracterizada por um posicionamento atípico dos odontoblastos, seguida pelo aparecimento de cálculos pulpares e posteriormente por uma aparente e uniforme acomodação tecidual em toda a polpa, com moderada incidência de fibras colágenas. No lado experimental, as alterações foram similares parecendo, porém, aumentar com o tempo, principalmente aos 30 dias, onde a imagem histológica era semelhante à do lado controle aos 10 dias. Os resultados obtidos permitiram concluir que a interferência oclusal provocou alterações no tecido conjuntivo pulpar tanto no lado experimental como no controle e que as mesmas foram proporcionais à direção dos movimentos mandibulares.

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In this work structural features of anionic microemulsions, containing the pharmaceutical biocompatible components soya phosphatidylcholine (SPC), eumulgin HRE 40 (EU) and sodium oleate (SO) as surfactant, cholesterol (CHO) as oil phase and aqueous buffer were studied. Microemulsions were formulated with and without the antitumor drug doxorubicin (DOX). The various microstructures characterized in the pseudo-temary phase diagram were analyzed by polarized light microscopy, small-angle X-ray scattering (SAXS) and X-ray diffraction (XRD) as well as by their ability to incorporate and release DOX. The experimental results demonstrated a correlation between the composition, the structural features and drug delivery. It was found that at higher cholesterol contents, the crystallization of CHO polymorph phases changed the mobility of DOX molecules. Droplets were formed with short-range spatial correlation from a microemulsion (ME) with a low surfactant:oil ratio. More ordered structures with lamellar arrangements formed by the increasing of the CHO proportions in the formulation may be due to CHO crystallization. The in vitro release of DOX showed that the presence of a high content of crystalline CHO prolongs the release of DOX from ME. The retention of DOX in the internal oil phase of the ME may modulate the drug release for a prolonged time. These results clearly demonstrate the potential of ME as a drug-delivery system. (c) 2007 Elsevier B.V. All rights reserved.

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

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Depending on the composition, the mixture of surfactant, oil and water, may form supramolecular aggregates with different structures which can significantly influence the drug release. In this work several microemulsion (ME) systems containing soya phosphatidylcholine (SPC) and eumulgin HRE40 (TM) (EU) as surfactant, cholesterol (O) as oil phase, and ultra-pure water as an aqueous phase were studied. MEs with and without the antitumoral drug doxorubicin (DOX) were prepared. The microstructures of the systems were characterized by photon correlation spectroscopy, rheological behavior, polarized light microscopy, small-angle X-ray scattering (SAXS) and X-ray diffraction (XRD). The results reveal that the diameter of the oil droplets was dependent on the surfactant (S) amount added to formulations. The apparent viscosity was dependent on the O/S ratio. High O/S ratio leads to the crystallization of cholesterol polymorphs phases which restricts the mobility of the DOX molecules into the ME structure. Droplets with short-range spatial correlation were formed from the ME with the low O/S ratio. The increase of the cholesterol fraction in the O/S mixture leads to the formation of ordered structures with lamellar arrangements. These different structural organizations directly influenced the drug release profiles. The in vitro release assay showed that the increase of the O/S ratio in the formulations inhibited the constant rate of DOX release. Since the DOX release ratio was directly dependent on the ratio of O/S following an exponential decay profile, this feature can be used to control the DOX release from the ME formulations. (C) 2008 Elsevier B.V. All rights reserved.

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Anatomical characterization and chemical profile of Laguncularia racemosa (L.) Gaertn leaf blades, from impacted and non-impacted mangroves of the São Paulo Coast. Several sources of environmental impact have caused great damage to the flora in mangroves. Therefore, this study aimed to analyze the anatomy and chemical composition of Laguncularia racemosa (L.) Gaertn leaf blades, from impacted (Municipality of Santos) and non-impacted mangroves (Municipality of Peruibe) of the São Paulo Coast. For the leaf anatomy studies, light microscopy and scanning electron microscopy (SEM) were used. For chemical analysis, high performance liquid chromatography (HPLC) was conducted. The biometry revealed leaf tissues of plants from impacted mangroves with a less thick epidermis and mesophyll and higher width of the central vascular beam. A smaller number of stomata and higher amounts of daises in these leaves were also observed. Results were confirmed by the Student t-test (alpha = 5%). The chemical profiles revealed a higher ammount of secondary metabolites in leaves from the impacted environment.

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

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

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O diagnóstico histopatológico do líquen plano bucal não é fácil, pois alguns casos de displasia epitelial podem apresentar características bastante semelhantes às do líquen plano. OBJETIVO: Comparar as alterações celulares sugestivas de malignidade presentes no líquen plano bucal com as da displasia epitelial. MATERIAL E MÉTODOS: Cortes histológicos de líquen plano bucal e displasia, corados com hematoxilina-eosina, foram analisados por meio da microscopia de luz. RESULTADOS: A análise de variância (alfa=5%) revelou haver diferença estatisticamente significante entre o número médio de alterações celulares no líquen plano bucal (5,83±1,61) e na displasia epitelial (4,46±1,26). O teste de qui-quadrado não mostrou diferença estatisticamente significante entre o líquen plano bucal e a displasia epitelial em relação às seguintes alterações celulares: aumento da relação núcleo/citoplasma, hipercromatismo nuclear, distribuição irregular da cromatina e núcleos aumentados (p>0,05). CONCLUSÃO: Algumas alterações celulares sugestivas de malignidade presentes no líquen plano bucal também podem ser encontradas na displasia epitelial, dificultando o seu diagnóstico e, consequentemente enfatizando a importância do acompanhamento a longo prazo dos pacientes com a doença.