946 resultados para Perfusion ex vivo de coeur de rat


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Malformations and possible damages to the urogenital system can be originated in the embryonic period. Moreover, fire guns, knives and accidents, where there is the disruption of the urethra, also cause these lesions. The objective was to analyze the contribution of tissue engineering in the construction of neo-urethra, developed by bioengineering. We performed an urothelial ex vivo expansion of cells in 3D scaffolds (platelet gel matrix and acellular porcine aorta) to assess the contribution of this technique in the construction of a neo-urethra. Mechanical dissociation was made of the inner wall of 10 North Folk rabbit’s bladder, weighing 2.5 to 3.0 kg. After dissociation the cell content was centrifuged and obtained a pellet of urothelial cells. The pellet was ressuspended in culture medium DMEM F12 and cells were maintained in culture for 15 days. Immunohistochemical analysis characterized the urothelial culture. The cells were then implanted in the scaffold - platelet gel. In a second experiment using aortic porcine acellular matrix were implanted urothelial cells alone and urothelial cells on platelet gel, on the inner wall of the scaffold - aorta, with space for setting bordered by a urethral probe. The complex probe - cells - aorta and probe - cells in platelet gel - aorta, were sealed with suture material and culture were maintained in a humidified 37ºC incubator with 5% CO2 in air for 12 days to subsequent histological analysis of urothelium cell adhesion to the scaffolds. By observation under an optical microscope, we could see the growth of cells in the scaffold platelet gel, from a monolayer in to a three-dimensional structure. In the acellular porcine aortic matrix containing the platelet gel, we could observe a few quantity of urothelial cells adhered. However with the acellular porcine aortic matrix in which was implanted only the urothelial cells, we have obtained adhesion to the wall

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Biological activities of flavonoids have been extensively reviewed in literature. The biochemical profile of afzelin, kaempferitrin, and pterogynoside acting on reactive oxygen species was investigated in this paper. The flavonoids were able to act as scavengers of the superoxide anion, hypochlorous acid and taurine chloramine. Although flavonoids are naturally occurring substances in plants which antioxidant activities have been widely advertised as beneficial, afzelin, kaempferitrin, and pterogynoside were able to promote cytotoxic effect. In red blood cells this toxicity was enhanced, depending on flavonoids concentration, in the presence of hypochlorous acid, but reduced in the presence of 2,20 -azo-bis(2-amidinopropane) free radical. These flavonoids had also promoted the death of neutrophils, which was exacerbated when the oxidative burst was initiated by phorbol miristate acetate. Therefore, despite their well-known scavenging action toward free radicals and oxidants, these compounds could be very harmful to living organisms through their action over erythrocytes and neutrophils.

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Background. Methods for determining the root canal length of the primary tooth should yield accurate and reproducible results. In vitro studies show some limitations, which do not allow their findings to be directly transferred to a clinical situation. Aim. To compare the accuracy of radiographic tooth length obtained from in vivo digital radiograph with that obtained from ex vivo digital radiograph. Method. Direct digital radiographs of 20 upper primary incisors were performed in teeth (2/3 radicular resorption) that were radiographed by an intraoral sensor, according to the long-cone technique. Teeth were extracted, measured, and mounted in a resin block, and then radiographic template was used to standardise the sensor-target distance (30 cm). The apparent tooth length (APTL) was obtained from the computer screen by means of an electronic ruler accompanying the digital radiography software (CDR 2.0), whereas the actual tooth length (ACTL) was obtained by means of a digital calliper following extraction. Data were compared to the ACTL by variance analysis and Pearson’s correlation test. Results. The values for APTL obtained from in vivo radiography were slightly underestimated, whereas those values obtained from ex vivo were slightly overestimated. No significance was observed between APTL and ACTL. Conclusion. The length of primary teeth estimated by in vivo and ex vivo comparisons using digital radiography was found to be similar to the actual tooth length.

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Introduction: The radiographic characteristics of a biomaterial, such as its density, may influence the evaluation of the results obtained following its clinical use. Objective: The aim of this study was to evaluate the radiographic density of biomaterials used as bone substitutes, inserted into dental sockets and bone defects in created in the jaws of pigs. The influence of a soft tissue simulator on the results was also evaluated. Material and method: Two and three-millimeter-deep bone defects were created in the pigs mandible and the right first molar extraction socket were used. Commercial samples of five biomaterials were tested: Hydroxyapatite, Lyophilized Bovine Bone, 45S5 bioglass (generic), PerioGlass and β-Tri-Calcium Phosphate, and compared to a positive (mandibular bone) and negative (empty alveolar bone defects) controls. Radiographic images were acquired with and without a 10 mm thick soft-tissue simulator. Result: The results for the extraction sockets showed no differences between the biomaterials and the negative control. For the bone defects, the depth of the defect density influenced the density, both in the negative control (p < 0.01) and biomaterials (p < 0.05) groups. The soft- tissue simulator did not alter the results. Conclusion: The type of the evaluated defect can interfere in the radiographic features presented by each biomaterial, while the simulation of soft tissues was not statistically significant.

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The main objective of this work was to mount and test an experimental model to measure the hydraulic conductance of ex vivo dentin. Seventeen healthy third molars, with indication of extraction of healthy donors aged between 15 and 30 years were obtained by informed consent. After cleaning them, disinfecting them, including them in resin epoxy and cutting them, there were 17 samples of dentin, corresponding to a disk of resin with a coronal section of tooth showing the dentin exposed on both sides of it. Three machines to measure the hydraulic conductance of the dentin were assembled according to the description of the model of Pashley. Samples were installed in a Chamber of diffusion, connected by using silicone tubes to a graduated transfer pipette and a 20cm water column. Through the displacement of a bubble of water in the inside of the pipette, the hydraulic conductance of each sample was measured 3 times on the 14th, 21st, 28th and 35th day post extraction. The data were tabulated and analyzed statistically. There is no SS difference in the rate of flow of a measured sample in the three machines (p=0.5937). There is no SS difference in measurements of the hydraulic conductance of 13 samples of human dentin measured in days 14, 21, 28 and 35 postextraction (p=0.0704). It is possible to mount an experimental model to study the hydraulic conductance of dentin ex vivo, based on the model of Pashley. The model seems to be reliable, but more research is needed in order to validate its reliability.

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The aim of the present study was to investigate the abrasive effect of CaCO3 and SiO2-based fluoride-free experimental toothpastes on eroded human permanent dental enamel and evaluate the effectiveness of waiting periods between acid exposure and tooth brushing. Twelve volunteers wore palatal appliances containing human enamel blocks for two periods of five days each. The appliances were immersed in a soft drink for five minutes four times a day (9:00 am, 11:00 am, 2:00 pm and 4:00 pm). On two occasions, two blocks were not submitted to additional treatment; two blocks were brushed (30 s) either with a CaCO3 or SiO2 toothpaste immediately after erosion and two blocks were brushed 1 h after erosion. Thus, the sample was divided into six groups: erosion alone (CaCO3 and SiO2 control); brushing with fluoride- free toothpaste (CaCO3 immediate and 1 h after erosion; SiO2 immediate and 1 h after erosion). Significant differences in wear depth were found between the enamel blocks in the CaCO3 immediate and 1 h after erosion groups and the blocks in the CaCO3 control group (p=0.001; p=0.022). No significant differences were found regarding the change in roughness and wear depth between blocks submitted to immediate abrasion and 1 h after erosion (CaCO3 and SiO2). The data revealed that surface roughness and wear depth is increased when erosion is combined with dental abrasion, regardless of the abrasive used. Waiting for 1 h to brush the eroded blocks offered no protective effect.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Cirurgia Veterinária - FCAV

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A doença de Chagas é uma doença parasitária causada pelo protozoário Trypanosoma cruzi (T. cruzi), que acomete o sistema digestivo e, principalmente, o cardíaco. É uma doença endêmica principalmente nos países da América Latina. A busca por novos fármacos para o tratamento dessa doença é de suma importância já que os existentes podem causar severos efeitos adversos e são efetivos somente na fase aguda. A molécula tiazolilhidrazona-9 (TZH-9) tem se destacado como uma excelente candidata a fármaco para tratamento da doença de Chagas e a continuidade de seu desenvolvimento deve envolver estudos de farmacocinética e metabolismo. Para a realização destes estudos é necessário o desenvolvimento e validação de um método bioanalítico para a determinação do composto em plasma, assim como avaliar a estabilidade do fármaco nesta matriz biológica com o intuito de verificar a ação de enzimas plasmáticas. Neste trabalho, foi desenvolvido e validado o método bioanalítico para quantificar o TZH-9 em plasma de ratos e humano que apresentou limites de confiança adequados. Também, avaliou-se a estabilidade do TZH-9 nessas matrizes biológicas, em plasma de ratos, o composto apresentou instabilidade após 2 horas na concentração inferior, sugerindo ação de enzimas plasmáticas no seu metabolismo; e em plasma de humanos, apresentou instabilidade após 15 minutos em ambas concentrações, sugerindo a susceptibilidade a ação das enzimas plasmáticas

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A doença de Chagas é uma doença parasitária causada pelo protozoário Trypanosoma cruzi (T. cruzi), que acomete o sistema digestivo e, principalmente, o cardíaco. É uma doença endêmica principalmente nos países da América Latina. A busca por novos fármacos para o tratamento dessa doença é de suma importância já que os existentes podem causar severos efeitos adversos e são efetivos somente na fase aguda. A molécula tiazolilhidrazona-9 (TZH-9) tem se destacado como uma excelente candidata a fármaco para tratamento da doença de Chagas e a continuidade de seu desenvolvimento deve envolver estudos de farmacocinética e metabolismo. Para a realização destes estudos é necessário o desenvolvimento e validação de um método bioanalítico para a determinação do composto em plasma, assim como avaliar a estabilidade do fármaco nesta matriz biológica com o intuito de verificar a ação de enzimas plasmáticas. Neste trabalho, foi desenvolvido e validado o método bioanalítico para quantificar o TZH-9 em plasma de ratos e humano que apresentou limites de confiança adequados. Também, avaliou-se a estabilidade do TZH-9 nessas matrizes biológicas, em plasma de ratos, o composto apresentou instabilidade após 2 horas na concentração inferior, sugerindo ação de enzimas plasmáticas no seu metabolismo; e em plasma de humanos, apresentou instabilidade após 15 minutos em ambas concentrações, sugerindo a susceptibilidade a ação das enzimas plasmáticas

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The success of endodontic treatment depends on the complete elimination of microorganisms from the root canal system, thus the search for new procedures to eliminate them is justified. The aim of this study was to assess bacterial reduction after intracanal irradiation with the Er:YAG laser. The canals of 70 extracted human maxillary canines were prepared up to file #40 using 1% NaOCl, irrigated with 17% EDTA, and then washed with physiological solution activated by ultrasound. The roots were sterilized by autoclaving, inoculated with 10 mu l of a suspension containing 1.5 x 10(8) CFU/ml of Enterococcus faecalis ATCC 29212 and incubated at 37A degrees C for 72 h. The canals were irradiated with the Er:YAG laser using two energy settings: 60 mJ and 15 Hz, and 100 mJ and 10 Hz. The remaining bacteria were counted immediately and 48 h after laser irradiation. The results showed a high bacterial reduction at both time points. With 60 mJ and 15 Hz there was an immediate reduction of 99.73% and the reduction was 77.02% after 48 h, and with 100 mJ and 10 Hz there was an immediate reduction of 99.95% and the reduction was 84.52% after 48 h. Although the best results were observed with 100 mJ of energy, the difference between the two settings was not statistically significant. The count performed 48 h after irradiation showed that E. faecalis were able to survive, and can grow even from small numbers.

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Objective: The aim of this study was to evaluate, ex vivo, the precision of five electronic root canal length measurement devices (ERCLMDs) with different operating systems: the Root ZX, Mini Apex Locator, Propex II, iPex, and RomiApex A-15, and the possible influence of the positioning of the instrument tips short of the apical foramen. Material and Methods: Forty-two mandibular bicuspids had their real canal lengths (RL) previously determined. Electronic measurements were performed 1.0 mm short of the apical foramen (-1.0), followed by measurements at the apical foramen (0.0). The data resulting from the comparison of the ERCLMD measurements and the RL were evaluated by the Wilcoxon and Friedman tests at a significance level of 5%. Results: Considering the measurements performed at 0.0 and -1.0, the precision rates for the ERCLMDs were: 73.5% and 47.1% (Root ZX), 73.5% and 55.9% (Mini Apex Locator), 67.6% and 41.1% (Propex II), 61.7% and 44.1% (iPex), and 79.4% and 44.1% (RomiApex A-15), respectively, considering ±0.5 mm of tolerance. Regarding the mean discrepancies, no differences were observed at 0.0; however, in the measurements at -1.0, the iPex, a multi-frequency ERCLMD, had significantly more discrepant readings short of the apical foramen than the other devices, except for the Propex II, which had intermediate results. When the ERCLMDs measurements at -1.0 were compared with those at 0.0, the Propex II, iPex and RomiApex A-15 presented significantly higher discrepancies in their readings. Conclusions: Under the conditions of the present study, all the ERCLMDs provided acceptable measurements at the 0.0 position. However, at the -1.0 position, the ERCLMDs had a lower precision, with statistically significant differences for the Propex II, iPex, and RomiApex A-15.

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Il presente studio ha come obbiettivo lo sviluppo di composti di origine naturale come potenziali farmaci antitumorali, attraverso la definizione dei loro specifici target cellulari e molecolari su diversi modelli cellulari ad alta predittività. Gli isotiocianati, contenuti nei vegetali appartenenti alla famiglia delle Crucifereae, sono dotati di una comprovata capacità di inibire la formazione di tumori in modelli animali preventivamente trattati con cancerogeni. Questa attività è riconducibile principalmente alla modulazione degli enzimi coinvolti nell’attivazione/detossificazione di xenobiotici e ad effetti citostatici e citossici, osservati su numerose linee cellulari. Un isotiocianato particolarmente promettente è il sulforafane (SFN). La ricerca condotta durante il periodo di dottorato si è, quindi, focalizzata sull’isotiocianato SFN e in particolare sulla sua capacità di modulare specifici eventi cellulari e molecolari coinvolti nel processo di leucemogenesi. Inizialmente è stato indagato il potenziale citostatico e citotossico del SFN su una linea cellulare T linfoblastoide (cellule Jurkat), con particolare attenzione agli effetti sulla proliferazione cellulare, all’induzione di apoptosi/necrosi e all’analisi di alcuni dei meccanismi molecolari coinvolti negli effetti citostatici e citotossici dell’isotiocianato ( livelli proteici di p53, bax e bcl-2). Successivamente, poiché requisiti fondamentali di un antitumorale sono selettività d’azione e scarsa tossicità, è stato indagato il potenziale citostatico e citotossico dell’isotiocianato SFN sulla controparte non trasformata delle cellule leucemiche T linfoblastoidi, analizzando gli stessi eventi studiati su cellule tumorali e alcuni dei meccanismi molecolari coinvolti (livelli proteici di ciclina D2, ciclina D3, chinasi ciclina dipendente (CDK) 4 e CDK6 ). Il SFN si è dimostrato in grado di indurre apoptosi sulle cellule Jurkat e di inibirne la proliferazione, mediante un blocco in fase G2/M del ciclo cellulare e un incremento dei livelli di p53 e bax. Il SFN è in grado di indurre effetti citostatici e citotossici anche su linfociti T non trasformati. Tuttavia, le dosi necessarie per esibire tali effetti sono ben più elevate di quelle attive su cellule leucemiche. Una tappa importante nello sviluppo di un farmaco antitumorale è, la definizione, dove possibile, dei suoi effetti in un modello ex vivo, altamente predittivo di quella che sarà la risposta farmacologica in vivo. Sono stati quindi valutati gli effetti del SFN su colture primarie di blasti provenienti da pazienti affetti da diversi tipi di leucemia , sia mieloide che linfoblastica. Il SFN non sembra possedere alcuna attività su campioni da pazienti affetti da LLC, mentre un importante attività proapoptotica si registra nei campioni da pazienti affetti da LMA, dove l’effetto del SFN è sorprendentemente marcato anche su campioni da pazienti multiresistenti. L’attività dell’isotiocianato sui campioni da pazienti affetti da LLA è decisamente più marcata sul campione da paziente affetto da LLA a cellule B, mentre sul campione di Leucemia Acuta Bifenotipica l’effetto proapoptotico del SFN si registra dopo tempi di trattamento brevi piuttosto che dopo tempi di trattamento più lunghi. In conclusione, i risultati ottenuti evidenziano che il SFN possiede un’interessante attività antileucemica in vitro e, dato di particolare rilevanza, anche ex vivo.