Avalia����o histopatol��gica da luxa����o extrusiva em molares de ratos

P��s-gradua����o em Odontologia - FOA

Estudos citogen��ticos para detec����o de marcadores de diagn��stico e progn��stico em sarcomas ��sseos

A busca pela identifica����o de fatores que possam apontar o diagn��stico, a resposta terap��utica e a sobrevida dos pacientes portadores de sarcoma ��sseos tem sido incessante. Presumir a agressividade tumoral, capacidade de invas��o tecidual, probabilidade de recidiva, propens��o ao desenvolvimento de met��stases e resposta ao tratamento, poder�� ser valioso expediente na escolha da proposta terap��utica. Embora fatores ambientais e diet��ticos contribuam para a etiologia do c��ncer, as neoplasias se originam de um processo de m��ltiplos passos envolvendo altera����es de genes e sele����o clonal da prog��nie variante. Estas muta����es ocorrem em classes de genes reguladores da prolifera����o celular como os oncogenes, genes supressores de tumor, fatores de crescimento, vias de sinaliza����o e genes de reparo de DNA. Os conhecimentos sobre a biologia tumoral melhoraram o entendimento sobre os m��ltiplos aspectos da carcinog��nese. No entanto, embora as perspectivas permane��am, at�� agora, h�� poucos benef��cios para preven����o, diagn��stico, tratamento e seguimento dos pacientes com sarcomas ��sseos. Este trabalho teve por objetivo detectar e descrever altera����es cromoss��micas consistentes e recorrentes, atrav��s da utiliza����o de an��lises com a citogen��tica cl��ssica. Tamb��m descreveu o envolvimento dessas altera����es com o progn��stico em sarcomas ��sseos prim��rios e secund��rios, na tentativa de contribuir para a realiza����o de estrat��gias mais eficazes para melhorar as taxas de sobrevida e beneficiar maior n��mero de pacientes portadores de sarcomas ��sseos. As les��es ��sseas apresentaram altera����es citogen��ticas clonas e recorrentes, das quais as principais foram: sarcoma pouco diferenciado, o qual apresentou del(7)(p21); osteossarcoma metast��tico, apresentando del(4)(q32), add(13)(p13), add(14)(p13); tumor de células gigantes com add(14)(p13); ...(Resumo completo, clicar acesso eletr��nico abaixo)

Odontoma em pacientes odontopedi��trico: diagn��stico e tratamento. Relato de caso cl��nico.

Odontoma is a term that refers to a benign tumor of odontogenic and mixed nature, composed of epithelial and mesenchymal components. Histologically, they are compounds of different configurations including dental enamel, dentin, cementum and in some cases the pulp tissue. A slow growing asymptomatic tumor, odontoma is usually discovered through routine radiographic examination. A 3-year old male patient sought care at the School of Dentistry���s Baby Clinic (UNESP-Ara��atuba), complaining of ���small ball close to the teeth.��� During the interview, the mother reported that the lesion was observed soon after a trauma, and evolved in less than one month. An ulcerated lesion with a 0.8 cm diameter was found during intraoral clinical examination. It was located in the inferior and anterior region of the mouth, between teeth 81 and 82, and there was also crown distalization. A radiographic examination showed a radiolucent area and root distance. In the absence of clinical and radiographic characteristics suggesting a case of odontoma, the differential diagnosis was peripheral giant cell lesion and pyogenic granuloma. So the area was punctured. Nonetheless, due to the absence of liquid, the surgical removal of the lesion was performed, followed by histological examination, which showed the definite diagnosis of a suggestive case of emerging odontoma.

Avalia����o da biocompatibilidade de implantes de silicone gel em subcut��neo de ratos: estudo histomorfom��trico

Objective: Histomorphometric study to evaluate the biological tissue compatibility of silicone implants suitable for plastic surgery. Methods: Thirty Wistar white rats received subcutaneous implants ande the revestiment of silicone gel Silimed, and randomized into six groups of five animals each, according to the type of implanted material and the time of sacrifice. Eight areas of 60.11 mm2 corresponding to the obtained surgical pieces were analyzed, counting mesenchymal cells, eosinophils, and foreign body giant cells, observing an acceptable biocompatibility in all implants, for subsequent statistical analysis by Tukey test. Results: Silicone gel showed inflammation slightly greater than for other groups, with tissue reactions varying from light to moderate, whose result was the formation of a fibrous capsule around the material, recognized by the organism as a foreign body. Conclusion: In general, it is possible to affirm that silicone gel had acceptable levels of biocompatibility, confirmed the rare presence of foreign body giant cells, and when of the rupture, formed a fibrous capsule around the material, separating the material of the organism.

Cisto ��sseo simples: relatos de casos

Usually diagnosed in routine radiographs, the simple bone cyst occurs infrequently. Etiology is unknown and differential diagnosis has to be made with dentigerous cyst, keratocystic odontogenic tumor, adenomatoid odontogenic tumor, ameloblastoma and central giant cell granuloma. Treatment is surgical, by perforating the cortical bone. In most cases an empty cavity, without any capsule or epithelial covering, is encountered, but it may have a liquid content. Perforation of the mandibular cortical bone elicits a response that results in bone repair of the empty cavity. This article reviews the subject and presents two cases of this entity and discusses the possible factors that could interfere in healing course.

Avalia����o microsc��pica da propriedade biol��gica e da biocompatibilidade do osso composto e do osso integral de origem bovina

The aim of this study was to evaluate the biological properties and biocompatibility of bovine non-demineralized lyophilized and composite bones implanted in tibiae bone cavities and at the subcutaneous level. Twenty-four rats were used and sacrificed 15 and 45 days later. At the subcutaneous level, after 15 days an inflammatory reaction was seen around biomaterial particles with the presence of giant cells and at 45 days fibrous connective tissue had also developed. No signs of ectopic bone formation were observed at tibiae regions; more bone neoformation was observed at the control group (15 days) with 42.8% of the outer cortex layer against 22.6% at Orthogen and 25% at GenMix groups. At 45 days, correspondent values for bone neoformation were 62.5% at control, 26% at Orthogen, and 35% at GenMix groups, respectively. It can be concluded that both materials tested were biocompatible aiming to bone neoformation by their osteoconductive properties with no ectopic formation sites observed.

Avalia����o histomorfom��trica dos efeitos da movimenta����o dent��ria induzida sobre molares de ratos submetidos �� luxa����o extrusiva

P��s-gradua����o em Odontologia - FOA

Propriedades f��sicas, qu��micas, antimicrobianas e biol��gicas de cimentos endod��nticos com ��xido de c��lcio e resina salicilato

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Rat subcutaneous tissue response to MTA Fillapex�� and Portland cement

The aim of this study was to evaluate the response of rat subcutaneous tissue to MTA Fillapex�� (Angelus), an experimental root canal filling material based on Portland cement and propylene glycol (PCPG), and a zinc oxide, eugenol and iodoform (ZOEI) paste. These materials were placed in polyethylene tubes and implanted into the dorsal connective tissue of Wistar rats for 7 and 15 days. The specimens were stained with hematoxylin and eosin, and evaluated regarding inflammatory reaction parameters by optical microscopy. The intensity of inflammatory response against the sealers was analyzed by two blinded and previously calibrated examiners for all experimental periods (kappa=0.96). The histological evaluation showed that all materials caused a moderate inflammatory reaction at 7 days, which subsided with time. A greater inflammatory reaction was observed at 7 days in the tubes filled with ZOEI paste. Tubes filled with MTA Fillapex presented some giant cells, macrophages and lymphocytes after 7 days. At 15 days, the presence of fibroblasts and collagen fibers was observed indicating normal tissue healing. The tubes filled with PCPG showed similar results to those observed in MTA Fillapex. At 15 days, the inflammatory reaction was almost absent at the tissue, with several collagen fibers indicating normal tissue healing. Data were analyzed by the nonparametric Kruskal-Wallis test (?=0.05). Statistically significant difference (p<0.05) was found only between PCPG at 15 days and ZOEI at 7 days groups. No significant differences were observed among the other groups/periods (p>0.05). MTA Fillapex and Portland cement added with propylene glycol had greater tissue compatibility than the PCPG paste.

Intralesional corticosteroid injections in the treatment of central giant cell lesions of the jaws

Objective: The aim of this study was to evaluate the response of treatment of central giant cell lesion to intralesional corticosteroid injections. Study Design: Review of articles indexed in PubMed on the topic between the years 1988 and 2011, and development of a descriptive meta-analysis of the results. Results: Sample of 41 patients primarily treated with intralesional corticosteroid injections was obtained, with a male female ratio of 1:0.95, being 23 aggressive and 18 non-aggressive central giant cell lesions. Triamcinolone acetonide and triamcinolone hexacetonide were the drugs used, and 78.0% cases were considered as good result, 14.6% were considered as moderate response and 7.3% were considered as negative result to treatment. Considering the aggressiveness, 88.9% of non-aggressive lesions presented a good response to treatment, in aggressive central giant cell lesions, 69.6% presented a good response to intralesional corticosteroid injections. Conclusion: In view of the results analyzed, intralesional corticosteroid injections could be considered as first treatment option for central giant cell lesion.

Central giant cell granuloma

Background: Central giant cell granuloma is a benign condition of the jaws which may present an aggressive behavior. Case report: A 9-year-old boy was complaining of swelling in the floor of the mouth. A solid swelling was observed in the area of the lower incisors. From the radiographic exam, we observed a radiolucent image in the mandibular bone with well-defined limits extending from the apical region of tooth 33 to the apical region of tooth 42. Discussion: Due to the diagnosis and the age of the patient, we chose a conservative treatment, administering subcutaneous injections of calcitonin. During this treatment, no reduction to the lesion was observed. Therefore, we chose to treat the lesion with triamcinolone acetonide. Monthly follow-ups demonstrated good lesion reduction and the absence of any clinical symptoms during the first 2 years. After a 3-year follow-up, the patient returned, presenting mobility of the lower incisors. A significant increase in the size of the lesion was observed. After a biopsy, with the removal of tissuewhich had the appearance of a cyst capsule, microscopic analyses were found to be compatible with a secondarily infected cyst. Two months following this procedure, the patient did not present tooth mobility anymore and the oral mucosa presented a normal aspect. Following a radiographic exam, full lesion repair was observed. These conservative treatments should be the first option in cases of central giant cell granuloma and the patient must be observed for a long period of time, until no further clinical or radiographic signs of lesions are observed

Expresi��n de la resistencia en plantas de tomate a nematodos formadores de n��dulos (Meloidogyne javanica)

La resistencia gen��tica mediada por los genes R es uno de los sistemas de defensa de las plantas frente a pat��genos y se activa una vez que los pat��genos han superado la defensa basal que otorgan la cut��cula y pared celular. Los mecanismos de resistencia gen��tica se inician a su vez, por el reconocimiento de productos derivados de genes de avirulencia de los pat��genos (avr) por parte de las prote��nas R. Tanto la respuesta de defensa basal como la respuesta de defensa por genes R est��n influenciadas por patrones de regulaci��n hormonal, que incluye a las principales hormonas vegetales ��cido salic��lico (SA), ��cido jasm��nico (JA) y etileno (ET). En tomate (Solanum lycopersicum) uno de los genes R es el gen MiG1, que confiere resistencia a nematodos formadores de n��dulos (Meloidogyne javanica, M. incognita y M. arenaria). Uno de los eventos m��s importantes que caracterizan a la respuesta de resistencia es la reacci��n hipersensible (HR), que est�� mediada por la activaci��n temprana de una serie de sistemas enzim��ticos, entre los que destaca el de las peroxidasas (PRXs) Clase III. Su funci��n es importante tanto para limitar el establecimiento y expansi��n del nematodo, al generar ambientes altamente t��xicos por su contribuci��n en la producci��n masiva de ROS, como por su implicaci��n en la s��ntesis y dep��sito de lignina generando barreras estructurales en el sitio de infecci��n. Adem��s de estos mecanismos de defensa asociados a la resistencia constitutiva, las plantas pueden desarrollar resistencia sist��mica adquirida (SAR) que en la naturaleza ocurre, en ocasiones, en una fase posterior a que la planta haya sufrido el ataque de un pat��geno. As�� mismo hay diferentes productos de origen qu��mico como el benzotiadiazol o BTH (��cido S-metil benzol-(1,2,3)-tiadiozole-7-carb��nico ester) que pueden generar esta misma respuesta SAR. Como resultado, la planta adquiere resistencia sist��mica frente a nuevos ataques de pat��genos. En este contexto, el presente trabajo aborda en primer lugar el an��lisis comparativo, mediante microarrays de oligonucle��tidos, de los transcriptomas de los sistemas radicales de plantas de tomate de 8 semanas de edad de dos variedades, una portadora del gen de resistencia MiG1 (Motelle) y otra carente del mismo y, por tanto, susceptible (Moneymaker), antes y despu��s de la infecci��n por M. javanica. Previo a la infecci��n se observ�� que la expresi��n de un gran n��mero de transcritos era m��s acusada en la variedad resistente que en la susceptible, entre ellos el propio gen MiG1 o los genes PrG1 (o P4), LEJA1 y ER24, lo que indica que, en ausencia de infecci��n, las rutas hormonales del SA, JA y ET est��n m��s activas en la ra��z de la variedad resistente. Por el contrario, un n��mero mucho menor de transcritos presentaban su expresi��n m��s reducida en Motelle que en Moneymaker, destacando un gen de se��alizaci��n para sintetizar la hormona giberelina (GA). La infecci��n por M. javanica causa importantes cambios transcripcionales en todo el sistema radical que modifican sustancialmente las diferencias basales entre plantas Motelle y Moneymaker, incluida la sobreexpresi��n en la variedad resistente de los transcritos de MiG1, que se reduce parcialmente, mientras que las rutas hormonales del SA y el JA continuan m��s activas que en la susceptible (evidente por los genes PrG1 y LEJA1). Adem��s, los cambios asociados a la infecci��n del nematodo se evidencian por las grandes diferencias entre los dos tiempos post-infecci��n considerados, de tal forma que en la fase temprana (2 dpi) de la interacci��n compatible predomina la sobreexpresi��n de genes de pared celular y en la tard��a (12 dpi) los relacionados con el ARN. En el an��lisis de la interacci��n incompatible, aunque tambi��n hay muchas diferencias entre ambas fases, hay que destacar la expresi��n diferencial com��n de los genes loxA y mcpi (sobrexpresados) y del gen loxD (reprimido) por su implicaci��n en defensa en otras interacciones planta-pat��geno. Cabe destacar que entre las interacciones compatible e incompatible hubo muy pocos genes en com��n. En la etapa temprana de la interacci��n compatible destac�� la activaci��n de genes de pared celular y la represi��n de la se��alizaci��n; en cambio, en la interacci��n incompatible hubo prote��nas principalmente implicadas en defensa. A los 12 d��as, en la interacci��n compatible los genes relacionados con el ARN y la pared celular se sobreexpresaban principalmente, y se reprim��an los de prote��nas y transporte, mientras que en la incompatible se sobreexpresaron los relacionados con el estr��s, el metabolismo secundario y el de hormonas y se reprimieron los de ARN, se��alizaci��n, metabolismo de hormonas y prote��nas. Por otra parte, la t��cnica de silenciamiento g��nico VIGS revel�� que el gen TGA 1a est�� implicado en la resistencia mediada por el gen MiG1a M. javanica. As�� mismo se evalu�� el transcriptoma de todo el sistema radical de la variedad susceptible tras la aplicaci��n del inductor BTH, y se compar�� con el transcriptoma de la resistente. Los resultados obtenidos revelan que el tratamiento con BTH en hojas de Moneymaker ejerce notables cambios transcripcionales en la ra��z; entre otros, la activaci��n de factores de transcripci��n Myb (THM16 y THM 27) y del gen ACC oxidasa. Las respuestas inducidas por el BTH parecen ser de corta duraci��n ya que no hubo transcritos diferenciales comunes a las dos fases temporales de la infecci��n comparadas (2 y 12 dpi). El transcriptoma de Moneymaker tratada con BTH result�� ser muy diferente al de la variedad resistente Motelle, ambas sin infectar, destacando la mayor expresi��n en el primero del gen LeEXP2, una expansina relacionada con defensa frente a nematodos. Las respuestas inducidas por los nematodos en Moneymaker-BTH tambi��n fueron muy distintas a las observadas previamente en la interacci��n incompatible mediada por MiG1, pues s��lo se detectaron 2 genes sobreexpresados comunes a ambos eventos. Finalmente, se abord�� el estudio de la expresi��n diferencial de genes que codifican PRXs y su relaci��n con la resistencia en la interacci��n tomate/M. javanica. Para ello, se realiz�� en primer lugar el estudio del an��lisis del transcriptoma de tomate de la interacci��n compatible, obtenido en un estudio previo a partir de tejido radical infectado en distintos tiempos de infecci��n. Se han identificado 16 unigenes de PRXs con expresi��n diferencial de los cuales 15 se relacionan por primera vez con la respuesta a la infecci��n de nematodos. La mayor��a de los genes de PRXs identificados, 11, aparecen fuertemente reprimidos en el sitio de alimentaci��n, en las células gigantes (CG). Dada la implicaci��n directa de las PRXs en la activaci��n del mecanismo de producci��n de ROS, la supresi��n de la expresi��n g��nica local de genes de PRXs en el sitio de establecimiento y alimentaci��n pone de manifiesto la capacidad del nematodo para modular y superar la respuesta de defensa de la planta de tomate en la interacci��n compatible. Posteriormente, de estos genes identificados se han elegido 4: SGN-U143455, SGN-U143841 y SGN-U144042 reprimidos en el sitio de infecci��n y SGN-U144671 inducido, cuyos cambios de expresi��n se han determinado mediante an��lisis por qRT-PCR y de hibridaci��n in situ en dos tiempos de infecci��n (2 dpi y 4 dpi) y en distintos tejidos radicales de tomate resistente y susceptible. Los patrones de expresi��n obtenidos demuestran que en la interacci��n incompatible la transcripci��n global de los 4 genes estudiados se dispara en la etapa m��s temprana en el sitio de infecci��n, detect��ndose la localizaci��n in situ de transcritos en el citoplasma de las células corticales de la zona meristem��tica afectadas por el nematodo. A 4 dpi se observ�� que los niveles de expresi��n en el sitio de infecci��n cambian de tendencia y los genes SGN-U144671 y SGN-U144042 se reprimen significativamente. Los diferentes perfiles de expresi��n de los genes PRXs en los dos tiempos de infecci��n sugieren que su inducci��n en las primeras 48 horas es crucial para la respuesta de defensa relacionada con la resistencia frente a la invasi��n del nematodo. Por ��ltimo, al analizar el tejido radical sist��mico, se detect�� una inducci��n significativa de la expresi��n en la fase m��s tard��a de la infecci��n del gen SGN-U144042 en el genotipo susceptible y del SGN-U143841 en ambos genotipos. En este estudio se describe por primera vez la inducci��n de la expresi��n sist��mica de genes de PRXs en tomate durante la interacci��n compatible e incompatible con M. javanica lo que sugiere su posible implicaci��n funcional en la respuesta de defensa SAR activada por la infecci��n previa del nematodo. ABSTRACT Plants defend themselves from pathogens by constitutive and/or induced defenses. A common type of induced defense involves plant resistance genes (R), which are normally activated in response to attack by specific pathogen species. Typically, a specific plant R protein recognizes a specific pathogen avirulence (avr) compound. This initiates a complex biochemical cascade inside the plant that results in synthesis of antipathogen compounds. This response can involve chemical signaling, transcription, translation, enzymes and metabolism, and numerous plant hormones such as salicylic acid (SA), jasmonates (JA) and ethylene (ET). Induced plant defense can also activate Class III peroxidases (PRXs), which produce reactive oxygen species (ROS), regulate extracellular H2O2, and play additional roles in plant defense. R-gene activation and the resulting induced defense often remain localized in the specific tissues invaded by the plant pathogen. In other cases, the plant responds by signaling the entire plant to produce defense compounds (systemic induction). Plant defense can also be induced by the exogenous application of natural or synthetic elicitors, such as benzol-(1,2,3)-thiadiazole-7-carbothionic acid. There is much current scientific interest in R-genes and elicitors, because they might be manipulated to increase agricultural yield. Scientists also are interested in systemic induction, because this allows the entire plant to be defended. In this context, one of the aims of this investigation was the transcriptoma analysis of the root systems of two varieties of tomato, the resistant variety (Motelle) that carrier MiG1 and the susceptible (Moneymaker) without MiG1, before and after infection with M. javanica. The overexpression was more pronounced in the transcriptoma of the resistant variety compared with susceptible, before infection, including the MiG1 gene, PrG1 (or P4) genes, LEJA1 and ER24, indicating that hormone SA, JA and ET are active in the resistant variety. Moreover, GA hormone presents an opposite behavior. M. javanica infection causes significant transcriptional changes in both compatible (Moneymaker-M. javanica) and incompatible (Motelle-M. javanica) interaction. In the incompatible transcriptome root system, was notably reduced the expression of the MiG1 gene, and a continuity in the expression of the hormonal pathways of SA and JA. In other hand, transcriptional profile changes during compatible interaction were associated with nematode infection. The large differences between the two times point infection considered (2 dpi and 12 dpi) indicates an overexpression of cell wall related genes in the first phase, and conversely an overexpression of RNA genes in the late phase. Transcriptoma analysis of incompatible interaction, although there were differences between the two phases, should be highlighted the common differential gene expression: loxA and mcpi (overexpressed) and loxD gene (suppressed), as they are involved in defenses in other plant-pathogen interactions. The VIGS tool has provided evidence that TGA 1a is involved in MiG1 mediated resistance to M. javanica. Likewise, the systemic application of BTH was assessed and compared with susceptible and resistant variety. Root system transcriptoma of BTH treatment on leaves showed the activation of Myb transcription factors (THM16 and THM27), the ACC oxidase gene. and the LeEXP2 gene, encoding for an expansin enzyme, related with defense against nematodes. The activation appears to be reduced by subsequent infection and establishment of nematodes. To assist in elucidate the role of tomato PRXs in plant defence against M. javanica, the transcriptome obtained previously from isolated giant cells (GC) and galls at 3 and 7 dpi from the compatible interaction was analysed. A total of 18 different probes corresponding to 16 PRX encoding genes were differentially expressed in infection site compared to the control uninfected root tissues. Most part of them (11) was down-regulated. These results yielded a first insight on 15 of the PRX genes responding to tomato���Meloidogyne interaction and confirm that repression of PRX genes might be crucial for feeding site formation at the initial stages of infection. To study the involvement of PRX genes in resistance response, four genes have been selected: SGN-U143455, SGN-U143841 and SGN-U144042 consistently down-regulated and SGN-U144671 consistently up-regulated at infection site in compatible interaction. The expression changes were determined by qRT-PCR and in situ location at 2 dpi and 4 dpi, and in different root tissues of resistant and susceptible plants. Early upon infection (2 dpi), the transcripts levels of the four genes were strongly increased in infected tissue of resistant genotype. In situ hybridization showed transcript accumulation of them in meristem cortical cells, where the nematode made injury. The results obtained provide strong evidence that early induction of PRX genes is important for defence response of the resistance against nematode invasion. Moreover, the induction patterns of SGN-U144042 gene observed at 4 dpi in distal noninfected root tissue into the susceptible genotype and of SGN-U143841 gene in both genotypes suggest a potential involvement of PRX in the systemic defence response.

Hiperparatiroidismo secund��rio e compromisso neurol��gico, que rela����o? : apresenta����o de um caso de osteodistrofia renal

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

Endometrial tuberculosis simulating an ovarian cancer

Female genital tuberculosis remains a major health problem in developing countries and is an important cause of infertility. As symptoms, laboratory data and physical fndings are non-specifc, its diagnosis can be diffcult. We describe a case of a 39-year-old woman suffering from peri-umbilical pain and increased abdominal size for one year, anorexia, asthenia, weight loss, occasionally dysuria and dyspareunia, and four months amenorrhea. Laboratory data revealed cancer antigen 125 (CA-125) level of 132.3 U/mL, erythrocyte sedimentation rate of 42 mm/h, and gamma-globulins of 2.66 g/dL. Computer Tomography scan showed loculated ascites. It was initially suspected a carcinomatous origin, but ascites evaluation was negative for malignant cells. Magnetic Resonance Imaging from another hospital showed endometrial heterogeneity. Therefore, an endometrial biopsy was performed demonstrating an infammatory infltrate with giant cells of type Langhans and bacteriological culture identifed Mycobacterium tuberculosis

Desenvolvimento e estudo em microcanais de fluidos inovadores an��logos ao sangue baseados em ves��culas unilamelares gigantes

O escoamento sangu��neo �� um dos temas de grande interesse para a comunidade cient��fica. Assim, a busca de fluidos que sejam an��logos ao sangue bem como o estudo do seu escoamento em microcanais, tal como acontece com o sangue nos capilares, continua a ser alvo de investiga����o. Numa primeira fase deste trabalho, procedeu-se ao desenvolvimento de um modelo inovador para produzir gl��bulos vermelhos artificiais, constitu��do por Ves��culas Unilamelares Gigantes, vulgarmente designadas Giant Unilamellar Vesicles (GUVs), com tr��s concentra����es diferentes. Pretende-se que estas ves��culas tenham um comportamento reol��gico id��ntico ao escoamento dos gl��bulos vermelhos (GVs) em microcanais, permitindo assim proceder a v��rios estudos hemodin��micos. No desenvolvimento destas ves��culas, foi verificado que as mais adequadas s��o constitu��das por uma mistura natural de l��pidos e lecitina de soja. Foi realizado um estudo relativamente �� sua concentra����o, onde se verificou que, com o aumento da quantidade da lecitina de soja nas solu����es, a concentra����o de GUVs tende a aumentar. Foi tamb��m realizado um estudo relativo aos di��metros dos GUVs para verificar se estes se aproximavam em termos de tamanho dos GVs, onde foi verificado que a maioria dos GUVs possuem di��metros com dimens��es entre os 5 e 7 ��m, tal como os GVs. Foi ainda verificado que a solu����o com a menor concentra����o de lecitina de soja possui uma maior quantidade de GUVs com di��metros entre os 5 e 7 ��m. Na segunda fase, foi estudado experimentalmente o escoamento das tr��s solu����es de GUVs em microcanais hiperb��licos, com tr��s caudais diferentes, com o objetivo de visualizar a Camada Livre de Células (CLC), determinar a deforma����o e estudar as velocidades destes. Foi verificado que existe a forma����o de CLC em todas as concentra����es e que aumenta com o aumento do caudal. Relativamente �� deforma����o, esta �� bastante mais evidente na contra����o do microcanal onde a taxa deforma����o �� m��xima. Para o caso da velocidade, foi observado um aumento bastante significativo e linear da velocidade na regi��o da contra����o do microcanal hiperb��lico e uma velocidade baixa e aproximadamente constante a montante e jusante da contra����o. vi Por fim, foi tamb��m realizado o estudo reol��gico dos GUVs, de forma a investigar se estes t��m uma viscosidade pr��xima do sangue. Foi verificado que os GUVs apresentam uma viscosidade inferior �� do sangue total e que existe um ligeiro aumento da viscosidade dos GUVs com o aumento da sua concentra����o. Por ��ltimo, tamb��m foi efetuada uma compara����o da viscosidade da solu����o de GUVs com uma solu����o de 5% de Hemat��crito (Hct) em soro fisiol��gico, onde foi verificado que ambas as viscosidades s��o muito pr��ximas.