919 resultados para Skin tissue engineeringSkin substitutesIn vitro test system
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Introducción: En la actualidad se están implementando nuevas técnicas, para el tratamiento de líneas de expresión facial. El Plasma Rico en Plaquetas (PRP) utiliza factores de crecimiento humano autólogos con fines médicos estéticos. El objetivo de este trabajo fue evaluar el tratamiento con plasma rico en plaquetas en el manejo del rejuvenecimiento periocular. Materiales y métodos: Estudio descriptivo retrospectivo en una cohorte de 27 pacientes entre 30 a 70 años de ambos sexos,tratados con PRP sin tratamientos médicos estéticos previos . Se compararon fotografías del sistema VISIA®, previo y posterior el PRP, para determinar los cambios del área periocular. Con análisis comparativo de medias utilizando pruebas t de student. Resultados: De 27 historias clínicas revisadas 96,3% eran mujeres, la edad promedio fue de 52.67 años. Se observaron cambios clínicos satisfactorios en el manejo del foto envejecimiento periocular con mejoría estadísticamente significativa entre el promedio inicial y el post tratamiento en arrugas, textura y porfirinas (p: 0.000). No se observaron diferencias estadísticamente significativas entre los grupos de edad (p = 0,62). Los pacientes analizados posterior al tratamiento se encuentran en mejor estado que el 63,78% de la población de su mismo sexo, edad y fototipo de piel. Los eventos adversos fueron disminuyendo en su frecuencia en cada una de las sesiones siguientes. Discusión: El PRP proporciona una mejoría global en los parámetros de envejecimiento periocular lo cual se correlaciono con los estudios previos in vitro. Conclusiones: El PRP es seguro y eficaz en contorno de ojos.
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El aumento en la resistencia bacteriana es un problema global que afecta también a nuestro país y que puede llevar a fracasos terapéuticos, peores desenlaces clínicos, uso de terapia combinada, mayor riesgo de interacciones medicamentosas y de reacciones adversas asi como a aumento de los costos del tratamiento. Tigeciclina, un nuevo antibiótico de la clase de las glicilciclinas ha mostrado una promisoria actividad antibacteriana in vitro contra bacterias comunes incluyendo multiresistentes que cada vez son más prevalentes en nuestro país especialmente a nivel hospitalario. Este estudio fue desarrollado para determinar la actividad de tigeciclina en nuestro medio y conocer su potencial utilidad.
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Los solventes orgánicos son sustancias químicas que por sus propiedades físico-químicas son fácilmente inhalados o absorbidos por la piel, pueden causar daños de diversa índole en la salud. En Colombia existen normas que contemplan las medidas de protección, sin embargo persiste la informalidad en el sector de pintores de autos, por lo cual los trabajadores expuestos, a largo plazo pueden ver afectada su salud. En este estudio se analizó la relación entre individuos expuestos laboralmente a los solventes orgánicos versus no expuestos con respecto a la longitud de sus telómeros y formación de fragilidades. Se emplearon muestras de sangre extraídas por venopunción, recolectada en dos tubos: uno con Heparina, destinado al cultivo de linfocitos, para obtener cromosomas metafásicos y evaluar en ellos la presencia de fragilidades; el otro tubo con EDTA, fue empleado para la extracción de ADN y se utilizó para obtener los valores de longitud telomérica mediante la técnica de PCR cuantitativa. Los análisis estadísticos se realizaron aplicando la prueba de rangos de Wilcoxon, en el caso de la presencia de fragilidades se analizó la razón No.Fragilidades/No.Metafases, aplicando el método de Wilcoxon se encontró que existe diferencia estadísticamente significativa entre expuestos y no expuestos (p = 0,036), en donde los expuestos presentan mayor frecuencia de fragilidades. Por otra parte el valor relativo de longitud telomérica del grupo de expuestos fue mayor que el observado en el grupo de no expuestos, esta diferencia fue estadísticamente significativa (Wilcoxon, p = 0.002).
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Penetration enhancers are chemicals that temporarily and reversibly diminish the barrier function of the outermost layer of skin, the stratum corneum, to facilitate drug delivery to and through the tissue. In the current study, the complex mechanisms by which 1,8-cineole, a potent terpene penetration enhancer, disrupts the stratum corneum barrier is investigated using post-mortem skin samples. In order to validate the use of excised tissue for these and related studies, a fibre optical probe coupled to an FT-Raman spectrometer compared spectroscopic information for human skin recorded from in vivo and in vitro sampling arrangements. Spectra from full-thickness (epidermis and dermis) post-mortem skin samples presented to the spectrometer with minimal sample preparation (cold acetone rinse) were compared with the in vivo system (the forearms of human volunteers). No significant differences in the Raman spectra between the in vivo and in vitro samples were observed, endorsing the use of post-mortem or surgical samples for this investigational work. Treating post-mortem samples with the penetration enhancer revealed some unexpected findings: while evidence for enhancer-induced disruption of the barrier lipid packing in the stratum corneum was detected in some samples, spectra from other samples revealed an increase in lipid order on treatment with the permeation promoter. These findings are consistent with phase-separation of the enhancer within the barrier lipid domains as opposed to homogeneous disruption of the lipid lamellae. Copyright (C) 2006 John Wiley & Sons, Ltd.
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Objective: This study investigated the effect of different sodium content diets on rat adipose tissue carbohydrate metabolism and insulin sensitivity. Methods and Procedures: Male Wistar rats were fed on normal- (0.5% Na+; NS), high- (3.12% Na+; HS), or low-sodium (0.06% Na+; LS) diets for 3, 6, and 9 weeks after weaning. Blood pressure (BP) was measured using a computerized tail-cuff system. An intravenous insulin tolerance test (ivITT) was performed in fasted animals. At the end of each period, rats were killed and blood samples were collected for glucose and insulin determinations. The white adipose tissue (WAT) from abdominal and inguinal subcutaneous (SC) and periepididymal (PE) depots were weighed and processed for adipocyte isolation and measurement of in vitro rates of insulin-stimulated 2-deoxy-d-[H-3]-glucose uptake (2DGU) and conversion of -[U-C-14]-glucose into (CO2)-C-14. Results: After 6 weeks, HS diet significantly increased the BP, SC and PE WAT masses, PE adipocyte size, and plasma insulin concentration. The sodium dietary content did not influence the whole-body insulin sensitivity. A higher half-maximal effective insulin concentration (EC50) from the dose - response curve of 2DGU and an increase in the insulin-stimulated glucose oxidation rate were observed in the isolated PE adipocytes from HS rats. Discussion: The chronic salt overload enhanced the adipocyte insulin sensitivity for glucose uptake and the insulin-induced glucose metabolization, contributing to promote adipocyte hypertrophy and increase the mass of several adipose depots, particularly the PE fat pad.
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The rates of oximolysis of p-nitrophenyl diphenyl phosphate (PNPDPP) by Acetophenoxime; 10-phenyl-10-hydi-oxyiminodecanoic acid; 4-(9-carboxynonanyl)-1-(9-carboxy-1-hydroyiminononanyl) benzene; 1-dodecyl-2-[(hydroxyimino)methyl]-pyridinium chloride (IV) and N-methylpyridinium-2-aldoxime chloride were determined in micelles of N-hexadecyl-N,N,N-trimethylammonium chloride (CTAC), N-hexadecyl-N,N-dimethylammonium propanesulfonate and dioctadecyldimethylammonium chloride (DODAC) vesicles. The effects of CTAC micelles and DODAC vesicles on the rates of oxymolysis of O,O-Diethyl O-(4-nitrophenyl) phosphate (paraoxon) by oxime IV were also determined. Analysis of micellar and vesicular effects on oximolysis of PNPDPP, using pseudophase or pseudophase with explicit consideration of ion exchange models, required the determination of the aggregate`s effects on the pK(a), of oximes and on the rates of PNPDPP hydrolysis. All aggregates increased the rate of oximolysis of PNPDPP and the results were analyzed quantitatively. In particular, DODAC vesicles catalyzed the reaction and increased the rate of oximolysis of PNPDPP by IV several million fold at pH`s compatible with pharmaceutical formulations. The rate increase produced by DODAC vesicles on the rate of oximolysis paraoxon by IV demonstrates the pharmaceutical potential of this system, since the substrate is used as an agricultural defensive agent and the surfactant is extensively employed in cosmetic formulations. (C) 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:1040-1052, 2009
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The aim of this study was to evaluate the tensile strength of orthodontic wires bonded onto the enamel with cyanoacrylate ester. To obtain the specimens, 120 human premolars (extracted for orthodontic or periodontal reasons) were included in acrylic blocks of rapid polymerization with three teeth each. Four groups were formed with ten specimens each. In the specimens, a dental splint model was made with cyanoacrylate ester and round stainless steel wire. In groups I, II and III, cyanoacrylate ester was used with round steel wires, with variation in diameter: 0.014 inches; 0.016 inches and 0.018 inches, respectively. In group IV, round steel wire 0.018 inches was used with photo polymerizing resin composite with previous acid etching. The adhesive force of the materials was measured in two points under the action of the tensiometer (ETM-USA). The number of loose wires was counted along with those that remained fixed according to the different levels of force applied because of the direction of the tensile force (vertical or horizontal) and the diameter of the wire used. The data obtained were first submitted to a descriptive analysis and then submitted to a statistical analysis (Friedman's Test and Dunn's Test of Multiple Comparison - Epi-info 3.2). Within the limitations of the experimental conditions presented, the cyanoacrylate ester or 'Super Bonder (R)' maintained bonded to enamel and steel wires (0.016 and 0.018 inches) during the tensile strength tests under different levels of applied forces.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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This study carried out an in vitro evaluation and comparison of the occurrence of marginal leakage in bonded restorations using mechanical or chemical-mechanical (Carisolv) removal of carious tissue. For that purpose, 40 extracted decayed human molars were divided into 4 groups: GI (burs + Prime & Bond NT + TPH), GII (Carisolv + Prime & Bond NT + TPH), GIII (burs + SBMP + Z100) and GIV (Carisolv + SBMP + Z100). After accomplishment of the restorations and thermal cycling, the teeth were exposed to dye, sectioned and qualitatively evaluated. The results demonstrated that the system of removal of carious tissue did not influence the results of microleakage at any of the cavity margins. At dentinal margins, use of the Prime & Bond NT + TPH restorative system allowed the occurrence of less microleakage than the SBMP + Z100 system.
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The purpose of this study was to evaluate the correlation between the hybrid layer thickness, resin tag length and resin bond strength of a self-etching adhesive system to sound dentin tissue in vivo. After performing restorative procedures and tooth extractions, ten specimens were sectioned in a mesiodistal direction. One dental section was used for light microscope analysis, in which both the resin tag length and hybrid layer thickness were measured, while the other section was analyzed using a microtensile test (0.5 mm/min). The fractured surface of the latter section was characterized using a stereoscopic magnifying glass (40x magnifcation). The results were subject to statistical analysis using the Pearson Correlation Test (a = 0.05). The hybrid layer thickness, resin tag length and resin bond strength mean values were 2.19 microm (0.34), 4.34 microm (0.28) and 9.73 MPa (5,55), respectively. In addition, correlation tests between the resin tag length and the resin bond strength (r=0.014) and also between the hybrid layer thickness and bond strength (r=0.43), showed no statistically significant correlation. The microtensile bond strength of Adper Prompt L Pop self-etching adhesive system does not depend on hybrid layer thickness or resin tag length.
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Cytotoxicity and subcutaneous tissue reaction of innovative blends composed by polyvinylidene fluoride and polyvinylidene fluoride-trifluoroethylene associated with natural polymers (natural rubber and native starch) forming membranes were evaluated, aiming its applications associated with bone regeneration. Cytotoxicity was evaluated in mouse fibroblasts culture cells (NIH3T3) using trypan blue staining. Tissue response was in vivo evaluated by subcutaneous implantation of materials in rats, taking into account the presence of necrosis and connective tissue capsule around implanted materials after 7, 14, 21, 28, 35, 60, and 100 days of surgery. The pattern of inflammation was evaluated by histomorphometry of the inflammatory cells. Chemical and morphological changes of implanted materials after 60 and 100 days were evaluated by Fourier transform infrared (FTIR) absorption spectroscopy and scanning electron microscopy (SEM) images. Cytotoxicity tests indicated a good tolerance of the cells to the biomaterial. The in vivo tissue response of all studied materials showed normal inflammatory pattern, characterized by a reduction of polymorphonuclear leukocytes and an increase in mononuclear leukocytes over the time (p < 0.05 Kruskal-Wallis). On day 60, microscopic analysis showed regression of the chronic inflammatory process around all materials. FTIR showed no changes in chemical composition of materials due to implantation, whereas SEM demonstrated the delivery of starch in the medium. Therefore, the results of the tests performed in vitro and in vivo show that the innovative blends can further be used as biomaterials. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 101B: 1284-1293, 2013. Copyright © 2013 Wiley Periodicals, Inc.
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Pós-graduação em Odontologia - FOAR
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Currently, there has been a growing concern for men and women with the appearance of the face and body, driven primarily by aesthetic standards set by the media. For this, the pharmaceutical and cosmetic industries have conducted numerous research projects aiming at the development of formulations that mitigate the aging and some skin disorders such as hipercromies. One of the most frequent pathologies of skin is melasma, a manifestation of hyperpigmentation caused by hipermelanogenesis symmetrical and progressive, caused usually by hormonal irregularities, exposure to sunlight and genetic factors. In addition to sunscreen, the treatment is indicated the use of depigmenting substances, among them the kojic dipalmitate (DK), which is cleaved into kojic acid (5- hydroxy-2-hydroxy-methyl-4H-piran-4-one) by esterase after absorption by the skin cells. The kojic acid inhibits the action of tyrosinase as a chelator of ions and promotes the reduction of eumelanin and its precursor monomer. To promote a controlled release and improve the stability of the system, the DK can be incorporated into multiple emulsions, that is, complex systems composed of two emulsifications, where the two types of emulsions (W/O and O/W or O/W and W/O) exist simultaneously, forming emulsions of type W/O/W or O/W/O. This work aimed to incorporate the DK in emulsion W/O/W, physical-chemical systems obtained and to evaluate the antioxidant and depigmenting action in vitro of the developed formulations. The physico-chemical characterization was performed by microscopic analysis, quantification and size distribution, determination of pH, conductivity, zeta potential and bioadhesive test of the formulations. The droplet size in accordance with the use of light microscopy and dynamic light scattering is approximately 1μm. The pH, electrical conductivity and bioadhesion have not changed with the addition... (Complete abstract click electronic access below)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)