81 resultados para Matriz extracelular Teses
Resumo:
Squamous cell carcinoma (SCC ) is the most common malignancy of the oral cavity (OSCC), with a high mortality rate. Due to this, the discovery of biomarkers that facilitate the understanding of the biological behavior of the tumor and improve treatment is necessary. Urokinase type plasminogen activator (uPA) and its receptor, uPAR, are responsible for the proteolysis of structures of the basement membrana and extracellular matrix, facilitating tumor invasion. This study aims to assess the immuno expression of these proteins in 46 cases of squamous cell carcinoma of the oral tongue (OTSCC). These results were related to the presence of metastasis, clinical TNM staging, locoregional recurrence, outcome of the lesion and histological grading. Immunostaining of each case was evaluated semiquantitatively, in the front of invasion and center of the tumor, in which scores were assigned: 0 (0% of positive cells), 1 (1-10% of positive cells), 2 (11 -50% positive cells) and 3 (more than 50% positive cells). The expression of uPA was observed in 93.5% (n=43) of the cases in the front of invasion, with predominance of score 2 (n=16; 34.8%) and in 67.9% (n=31) of the cases in the center of the tumor, with predominance of score 1 (n=15; 32.6%). Overall, the immunoexpression of uPA was not associated with clinical parameters. Regarding the malignant histological grading, a higher expression of uPA was observed in cases of high-grade malignancy comp ared to low-grade malignancy (p=0.05). Regarding the morphological parameters, increased expression of uPA was observed in the worst mode of invasion (p=0.03 ). The expression of uPAR was observed in 73.9% of cases in the front of invasion, with a predominance of score 1 (n=21; 45.6 %), and in 47.5% (n=21) of the cases in the center of the tumor, with a predominance of score 0 (n=25; 54.4%). Although no statistical differences were observed in relation to lymph node metastasis, clinical TNM staging, outcome, and histological grading, there was a higher expression of uPAR in cases with locoregional recurrence (p=0.04). Regarding the tumor intra -localization, it was observed an increased expression of uPA and uPAR at the front of invasion in relation to the center of the tumor (p<0.001). Regarding the correlation between uPA and uPAR, there was no statistical sign ificance. Based on these results, it is suggested that uPA and uPAR are involved in the progression of CELO, mainly in the deeper region of the tumor.
Resumo:
Squamous cell carcinoma (SCC ) is the most common malignancy of the oral cavity (OSCC), with a high mortality rate. Due to this, the discovery of biomarkers that facilitate the understanding of the biological behavior of the tumor and improve treatment is necessary. Urokinase type plasminogen activator (uPA) and its receptor, uPAR, are responsible for the proteolysis of structures of the basement membrana and extracellular matrix, facilitating tumor invasion. This study aims to assess the immuno expression of these proteins in 46 cases of squamous cell carcinoma of the oral tongue (OTSCC). These results were related to the presence of metastasis, clinical TNM staging, locoregional recurrence, outcome of the lesion and histological grading. Immunostaining of each case was evaluated semiquantitatively, in the front of invasion and center of the tumor, in which scores were assigned: 0 (0% of positive cells), 1 (1-10% of positive cells), 2 (11 -50% positive cells) and 3 (more than 50% positive cells). The expression of uPA was observed in 93.5% (n=43) of the cases in the front of invasion, with predominance of score 2 (n=16; 34.8%) and in 67.9% (n=31) of the cases in the center of the tumor, with predominance of score 1 (n=15; 32.6%). Overall, the immunoexpression of uPA was not associated with clinical parameters. Regarding the malignant histological grading, a higher expression of uPA was observed in cases of high-grade malignancy comp ared to low-grade malignancy (p=0.05). Regarding the morphological parameters, increased expression of uPA was observed in the worst mode of invasion (p=0.03 ). The expression of uPAR was observed in 73.9% of cases in the front of invasion, with a predominance of score 1 (n=21; 45.6 %), and in 47.5% (n=21) of the cases in the center of the tumor, with a predominance of score 0 (n=25; 54.4%). Although no statistical differences were observed in relation to lymph node metastasis, clinical TNM staging, outcome, and histological grading, there was a higher expression of uPAR in cases with locoregional recurrence (p=0.04). Regarding the tumor intra -localization, it was observed an increased expression of uPA and uPAR at the front of invasion in relation to the center of the tumor (p<0.001). Regarding the correlation between uPA and uPAR, there was no statistical sign ificance. Based on these results, it is suggested that uPA and uPAR are involved in the progression of CELO, mainly in the deeper region of the tumor.
Resumo:
INTRODUCTION AND OBJECTIVE: The study of biological behavior of odontogenic lesions is essential to the establishment of appropriate therapeutic approach and prognosis. The production of extracellular matrix metalloproteinases (MMPs), angiogenesis and cell proliferation contribute to tumor growth. This paper aims to review the literature on odontogenic tumors (OT) selected according to the new World Health Organization classification (WHO- 2005) by evaluating the expression of MMPs, angiogenic and cell proliferation. Furthermore, it aims to verify the relation between these markers and the biological behavior of these lesions. RESULTS: it was found that MMPs -1, -2, -7, -9 and -26 had a higher expression in both epithelial component and stroma, and 13 particularly in the stroma. Increased angiogenesis was observed in more aggressive OT. CD105 expression was higher in keratocystic odontogenic tumour (KOT) and CD34 in solid ameloblastomas (SA). It was observed a higher expression of Ki-67 and p53 in SA and KOT and a low cell proliferation rate in the adenomatoid odontogenic tumour (AOT). CONCLUSION: These results show that MMPs are involved in invasion and recurrence of some odontogenic lesions and are associated with the biological behavior of these tumors. Angiogenesis is critical to provide support to cell proliferation and these concomitant events are correlated with different levels of biological behavior in OT when compared to odontogenic cysts, hence the use of angiogenic inhibitors may be a potential therapeutic approach in these lesions.
Resumo:
INTRODUCTION AND OBJECTIVE: The study of biological behavior of odontogenic lesions is essential to the establishment of appropriate therapeutic approach and prognosis. The production of extracellular matrix metalloproteinases (MMPs), angiogenesis and cell proliferation contribute to tumor growth. This paper aims to review the literature on odontogenic tumors (OT) selected according to the new World Health Organization classification (WHO- 2005) by evaluating the expression of MMPs, angiogenic and cell proliferation. Furthermore, it aims to verify the relation between these markers and the biological behavior of these lesions. RESULTS: it was found that MMPs -1, -2, -7, -9 and -26 had a higher expression in both epithelial component and stroma, and 13 particularly in the stroma. Increased angiogenesis was observed in more aggressive OT. CD105 expression was higher in keratocystic odontogenic tumour (KOT) and CD34 in solid ameloblastomas (SA). It was observed a higher expression of Ki-67 and p53 in SA and KOT and a low cell proliferation rate in the adenomatoid odontogenic tumour (AOT). CONCLUSION: These results show that MMPs are involved in invasion and recurrence of some odontogenic lesions and are associated with the biological behavior of these tumors. Angiogenesis is critical to provide support to cell proliferation and these concomitant events are correlated with different levels of biological behavior in OT when compared to odontogenic cysts, hence the use of angiogenic inhibitors may be a potential therapeutic approach in these lesions.
Resumo:
Fucan is a term used to denominate a family of sulfated polysaccharides rich in L-fucose. They are extracted mainly from the extracellular matrix of brown algae and echinoderms. The brown alga Spatoglossum schrederi (Dictyotaceae) has three heterofucans named A, B and C. Our research group have been extracted non anticoagulant heterofucan from S. schrederi which possess antithrombotic activity in vivo. However, their toxicity in vitro and in vivo has not yet been determined. For the results in toxicity in vitro, we observed that the fucan A at 20, 500 and 1000 μg/plate showed no mutagenic activity in Kado test (Microsuspension), when the bacterial strains TA97a, TA98, TA100 and TA102, with and without S9 were used. The comet assay showed that fucan A (from 20 to 1000 μg/mL) did not cause any genotoxic effect on CHO cells. There was no damage to the DNA of these cells, as evidenced by the tail length and tail moment, which were similar to that found for the negative control. The fucan A from S. schrederi was administered at 20 μg/g of rat (dose which it showed high antithrombotic activity) during two months. After that, the animals were killed and examined. The data showed that fucan A did not cause any change in biochemistry and hematological parameters, as well as, in the morphology and size of the rat s organs analyzed. In conclusion, this study indicates that fucan is a compound with potential pharmacological that has no toxicity
Resumo:
Marine algae are one of the major sources of biologic compounds. In extracellular matrix of these organisms there are sulfated polysaccharides that functions as structural components and provides protection against dehydration. The fraction 1.0 (F1.0) rich in sulfated galactans obtained from red seaweed Hypnea musciformis was physicochemical characterized and evaluated for pharmacologic activity through antioxidant activity, cytotoxic action on erythrocytes, anticoagulant, stimulatory action under antithrombotic heparan sulfate synthesis and their effects on cell proliferation and cycle cell progression. The main components of F1.0 were carbohydrates (49.70 0.10%) and sulfate (44.59 0.015%), presenting phenolic compounds (4.79 0.016%) and low protein contamination (0.92 0.001%). Fraction 1.0 showed polidisperse profile and signs in infrared analysis in 1262, 1074 and 930, 900 and 850 attributed to sulfate esters S=O bond, presence of a 3,6- anidrogalactose C-O bond, non-sulfated -D-galactose and a C-O-SO4 bond in galactose C4, respectively. The fraction rich in sulfated galactans exhibited strong antioxidant action under lipid peroxidation assay with IC50 of 0.003 mg/mL. Besides the inhibition of hemolysis induced by H2O2 in erythrocytes treated with F1.0, this fraction did not promote significant cytotoxity under erythrocytes membranes. F1.0 exhibited low anticoagulant activity causing moderate direct inhibition of enzimatic activity of thrombin. This fraction promoted stimulation around of 4.6 times on this synthesis of heparan sulfate (HS) by rabbit aortic endothelial cells (RAEC) in culture when was compared with non treated cells. The fraction of this algae displayed antiproliferative action under RAEC cells causing incresing on cell number on S fase, blocking the cycle cell progression. Thus F1.0 presented cytostatic and no cytotoxic action under this cell lineage. These results suggest that F1.0 from H. musciformis have antioxidant potential which is a great effect for a compound used as food and in food industry which could be an alternative to food industry to prevent quality decay of lipid containing food due to lipid peroxidation. These polysaccharides prevent the lipid peroxidation once the fraction in study exhibited strong inhibitory action of this process. Furthermore that F1.0 present strong antithrombotic action promoting the stimulation of antithrombotic HS synthesis by endothelial cells, being important for thrombosis preventing, by its inhibitory action under reactive oxygen species (ROS) in some in vitro methods, being involved in promotion of hypercoagulability state.
Resumo:
Seaweeds are a major source of biologically active compounds . In the extracellular matrix of these organisms are sulfated polysaccharides that functions as structural components preventing it against dehydration. The fraction 0.9 (FucB) rich in sulfated fucans obtained from brown seaweed Dictyota menstrualis was chemical characterized and evaluated for pharmacological activity by testing anticoagulant activity, stimulatory action on the synthesis of an antithrombotic heparan sulfate, antioxidant activity and its effects in cell proliferation. The main components were FucB carbohydrates (49.80 0.10 %) and sulfate (42.30 0.015 %), with phenolic compounds ( 3.86 0.016 %) and low protein contamination ( 0.58 0.001 % ) . FucB showed polydisperse profile and analysis of signals in the infrared at 1262, 1074 and 930 cm -1 and 840 assigned to S = O bonds sulfate esters , CO bond presence of 3,6- anhydrogalactose , β -D- galactose non- sulfated sulfate and the axial position of fucose C4 , respectively. FucB exhibited moderate anticoagulant activity , the polysaccharides prolonged time (aPTT ) 200 ug ( > 90s ) partial thromboplastin FucB no effect on prothrombin time (PT), which corresponds to the extrinsic pathway of coagulation was observed. This stimulation promoted fraction of about 3.6 times the synthesis of heparan sulfate (HS) by endothelial cells of the rabbit aorta ( RAEC ) in culture compared with cells not treated with FucB . This has also been shown to compete for the binding site with heparin. The rich fraction sulfated fucans exhibited strong antioxidant activity assays on total antioxidant (109.7 and 89.5 % compared with BHT and ascorbic acid standards ) , reducing power ( 71 % compared to ascorbic acid ) and ferric chelation ( 71 , comparing with 5 % ascorbic acid). The fraction of algae showed cytostatic activity on the RAEC cells revealed that the increase of the synthesis of heparan sulfate is not related to proliferation. FucB showed antiproliferative action on cell lines modified as Hela and Hep G2 by MTT assay . These results suggest that FucB Dictyota menstrualis have anticoagulant , antithrombotic , antioxidant potential as well as a possible antitumor action, promoting the stimulation of the synthesis of antithrombotic HS by endothelial cells and is useful in the prevention of thrombosis, also due to its inhibitory action on species reactive oxygen ( ROS ) in some in vitro systems , being involved in promoting a hypercoagulable state
Resumo:
VITULLO, Nadia Aurora Vanti. Avaliao do banco de dissertaes e teses da Associao Brasileira de Antropologia: uma anlise cienciomtrica. 2001. 143 f. Dissertaao (Mestrado) - Curso de Mestrado em Biblioteconomia e Cincia da Informao, Pontifcia Universidade Catlica de Campinas, Campinas, 2001.
Resumo:
OLIVEIRA, Raimundo Muniz de. Biblioteca digital de teses e dissertaoes: uma referencia fundamental. In: CINFORM ENCONTRO NACIONAL DE ENSINO E PESQUISA DA INFORMAAO,HUMANISMO E DESENVOLVIMENTO CIENTIFICO E TECNOLOGICO,7.,2007,Salvador. Anais...Salvador:UFBA, 2007.Disponivel em:www.cinform.ufba.br>. Acesso em: 27 set. 2007. Acesso em: 27 set. 2010.
Resumo:
CUNHA, Jacqueline de Arajo. Biblioteca Digital de Teses e Dissertaes: uma estratgia de preservao da memria cientfica. 2009. 141f. Dissertao (Mestrado)- Programa de Ps-Graduao em Cincia da Informao. Universidade Federal da Paraba, Joo Pessoa, 2009.
Resumo:
A pesquisa aborda o uso das Tecnologias de Informao e Comunicao, que vem revolucionando as atividades e ocasionando muitas mudanas relacionadas ao acesso e uso de informaes. O objetivo foi analisar o grau de utilizao do conhecimento cientfico produzido pelos Programas de Ps-Graduao das Universidades Pblicas Brasileiras, atravs da BDTD, pelos mestrandos dos referidos programas. Nos procedimentos metodolgicos realizados, procurou-se inicialmente analisar o amplo espectro da populao do corpus da pesquisa. Em razo da impossibilidade de trabalhar com os Programas de Ps-Graduao como um todo, optou-se por fazer um recorte, elegendo os cursos de Ps-Graduao em Cincia da Informao, vez que estes representam o principal segmento social de interesse da pesquisa. Foi utilizado o mtodo de estudo de usurios, onde se optou por adotar o grupo, estudos orientados aos usurios, que identifica as necessidades e comportamento de acesso e uso da informao. Para coletar os dados, elaborou-se um questionrio semi-estruturado com 25 questes, que versavam sobre o uso, dificuldades de acesso e recuperao da informao, bem como a satisfao na utilizao dessa fonte informacional. Dentre os vrios resultados obtidos, podemos destacar o fato de que a maioria dos mestrandos (71,8%) s teve contato com a BDTD somente no momento em que se encontrava cursando o mestrado e, somente 24,3%, tiveram contato durante a graduao. Estes resultados representam um problema, que pode afetar o bom desempenho do projeto BDTD, o qual consiste em disseminar e divulgar a produo cientfica dos Programas de Ps-Graduao das Universidades Pblicas Brasileiras para a sua comunidade. Foi observado tambm, que os mestrandos oriundos do curso de Biblioteconomia tende a ter contato com a BDTD bem mais cedo do que mestrandos de outros cursos de graduao. A fim de minimizar o problema detectado, prope-se uma divulgao mais eficaz na graduao atravs de dois procedimentos: Primeiro, o docente deve fazer uma divulgao mais eficaz da BDTD junto aos discentes de todos os cursos de graduao; segundo: dever ser feita a divulgao na mdia eletrnica, atravs da insero de cones da BDTD, nos portais dos Departamentos dos Cursos de Graduao das Universidades Pblicas Brasileiras. Acredita-se que com estes procedimentos seja possvel aperfeioar o uso dessa fonte de informao cientfica.
Bibliotecas digitais de teses e dissertaes brasileiras: paradigma do acesso livre informao cientfica
Resumo:
A evoluo da comunicao cientfica ao longo do tempo e o impacto causado pela A evoluo da comunicao cientfica ao longo do tempo e o impacto causado pela A evoluo da comunicao cientfica ao longo do tempo e o impacto causado pela se analisar as contribuies da Biblioteca Digital de Teses e Dissertaes (BDTD)para a comunicao cientfica atual, destacando possibilidades emergentes e desafios a serem superados. Apresenta uma breve evoluo da comunicao cientfica ao longo do tempo; discute os impactos causados pela Internet na comunicao, disponibilizao e acessibilidade de informaes tcnico-cientficas; e caracteriza BDTD destacando os desafios a serem superados. Dentre eles esto, a questo dos direitos autorais que ocasionam a baixa adeso dos autores ao projeto piloto do IBICT para disponibilizar teses e dissertaes no meio eletrnico. Para este desafio, so apontadas sugestes.
Resumo:
As bibliotecas de teses e dissertaes tm um papel fundamental para o desenvolvimento cientfico e cultural de um pas. Nesse sentido, buscou-se, de modo geral, analisar o panorama brasileiro das bibliotecas digitais de teses e dissertaes. Especificamente, objetivou-se caracterizar a sociedade da informao enquanto contexto das BDTD; caracterizar os vrios tipos de bibliotecas surgidos a partir da insero das novas tecnologias de informao e comunicao; identificar as diretrizes norteadoras da implantao de BDTD; e levantar as BDTD existentes no Brasil. Para tato, alm de levantamento bibliogrfico, realizou-se uma pesquisa nos sites de instituies de ensino superior brasileiras que j dispe de bibliotecas digitais de teses e dissertaes em funcionamento. A anlise e interpretao destes dados nos permite considerar que no Brasil as BDTD encontram-se num estgio embrionrio, sendo relevante pesquisar a histrica implantao e configurao desse novo modelo de biblioteca.
Resumo:
Nowadays the environmental issues are increasingly highlighted since the future of humanity is dependent on the actions taken by man. Major efforts are being expended in pursuit of knowledge and alternatives to promote sustainable development without compromising the environment. In recent years there has been a marked growth in the development of reinforced composite fiber plants, as an alternative for economic and ecological effects, especially in the substitution of synthetic materials such as reinforcement material in composites. In this current study the chemical- physical or (thermophysics )characteristics of the babassu coconut fiber, derived from the epicarp of the fruit (Orbignyda Phalerata), which the main constituents of the fiber: Klason lignin, insoluble, cellulose, holocellulose, hemicellulose and the content of ash and moisture will be determined. A study was conducted about the superficial modification of the fibers of the epicarp babassu coconut under the influence of chemical treatment by alkalinization, in an aqueous solution of NaOH to 2.5% (m/v) and to 5.0% to improve the compatibility matrix / reinforcement composite with epoxy matrix. The results of the changes occurred in staple fibers through the use of the techniques of thermogravimetric analyses (TG) and differential scanning calorimetry (DSC). The results found on thermal analysis on samples of fiber without chemical treatment (alkalinities), and on fiber samples treated by alkalinization show that the proposed chemical treatment increases the thermal stability of the fibers and provides a growth of the surface of area fibers, parameters that enhance adhesion fiber / composite. The findings were evaluated and compared with published results from other vegetable fibers, showing that the use of babassu coconut fibers has technical and economic potential for its use as reinforcement in composites
Resumo:
Microalloyed steels constitute a specific class of steel with low amount of carbon and microalloying elements such as Vanadium (V), Niobium (Nb) and Titanium (Ti). The development and application of microalloyed steels and steels in general are limited to the handling of powders with particles of submicron or nanometer dimensions. Therefore, this work presents an alternative in order to construction of microalloyed steels utilizing the deposition by magnetron sputtering technique as a microalloying element addiction in which Ti nanoparticles are dispersed in an iron matrix. The advantage of that technique in relation to the conventional metallurgical processes is the possibility of uniformly disperse the microalloying elements in the iron matrix. It was carried out deposition of Ti onto Fe powder in high CH4, H2, Ar plasma atmosphere, with two deposition times. After the deposition, the iron powder with nanoparticles of Ti dispersed distributed, were compacted and sintered at 1120 C in resistive furnace. Characterization techniques utilized in the samples of powder before and after deposition of Ti were Granulometry, Scanning Electron Microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (DRX). In the case of sintered samples, it was carried out characterization by SEM and Vickers Microhardness assays. The results show which the deposition technique by magnetron sputtering is practicable in the dispersion of particles in iron matrix. The EDX microanalysis detected higher percentages of Ti when the deposition were carried out with the inert gas and when the deposition process was carried out with reactive gas. The presence of titanium in iron matrix was also evidenced by the results of X-ray diffraction peaks that showed shifts in the network matrix. Given these results it can be said that the technique of magnetron sputtering deposition is feasible in the dispersion of nanoparticles of iron matrix in Ti.