RESUMO
A large number of materials with different compositions and shapes have been proposed and studied for the purpose of bone tissue regeneration. Collagen-based materials have shown promising results for this application, with improved physicochemical properties. The aim of the present in vivo animal study was to evaluate and compare two commercially available collagen-based biomaterials for bone regeneration, with these being implanted in circumferential bone defects created in the calvarium of rabbits. Twenty rabbits received bilateral parietal osteotomies, performed with the aid of a 6.5 mm diameter trephine. Two groups were created: the BC group, where the defect was filled with a scaffold composed of 90% bovine bone particles and 10% porcine collagen, and the EG group, where the defect was filled with a scaffold composed of 75% hydroxyapatite particles of bovine origin and 25% bovine collagen. Ten animals were sacrificed at 30 days and another 10 at 45 days after implantation, and the samples were processed and histologically analyzed. In the evaluations of the samples at 30 days, no important differences were found in the results. However, in the samples at 45 days after surgery, the EG group showed better results than the BC group samples, mainly in terms of the amount of bone matrix formation (P < 0.0001) and the volume in area measured in each sample, where the EG group had a value 65% higher than that in the BC group samples. Based on the results obtained, we conclude that the amount of collagen and the particle characteristics present in the composition of the scaffolds can directly influence the amount of neoformation and/or bone regeneration.
Assuntos
Materiais Biocompatíveis , Colágeno , Animais , Materiais Biocompatíveis/química , Regeneração Óssea , Bovinos , Colágeno/química , Durapatita , Coelhos , Crânio , SuínosRESUMO
RESUMO O Lasik é a técnica de cirurgia refrativa mais utilizada no mundo. Apesar de segura e efetiva, ela pode levar a algumas complicações. O crescimento epitelial pós-Lasik é uma complicação pós-operatória incomum, com prevalência maior em casos de retratamento. Geralmente, é um achado não progressivo e assintomático, que não requer tratamento, mas, em uma minoria de pacientes, os sintomas podem ser clinicamente significantes e variados. O tratamento é feito com debridamento mecânico do crescimento epitelial, mas alguns recursos adjuvantes também podem ser utilizados. O presente estudo consiste em um relato de caso de paciente com crescimento epitelial pós-Lasik que apresentou quatro recidivas após intervenções de debridamento epitelial, sutura de lamela corneana e ablação a laser. No quinto procedimento, o paciente foi finalmente tratado com combinação de debridamento epitelial, uso de álcool a 20% e cola de fibrina. Entretanto, a regressão do crescimento epitelial e a melhora da acuidade visual só ocorreram ao longo dos meses após a intervenção, o que mostra a importância de esperar um tempo para que ocorra a melhora da visão no pós-operatório, evitando-se reintervenções.
ABSTRACT Lasik is the most often performed laser refractive surgery worldwide. Despite its efficacy and safety, some complications may occur. Epithelial ingrowth is a rare postoperative complication of Lasik, with an increased prevalence in cases of retreatment. Epithelial ingrowth is usually a nonprogressive and asymptomatic finding, which requires no treatment; however, in a minority of cases, symptoms may be clinically significant and diverse. Treatment is done with mechanical debridement of the affected interface, and additional interventions may be required. This study reported a case of recalcitrant epithelial ingrowth after Lasik, whichrelapsed four times after mechanical debridement, flap lift and laser ablation. In the fifth intervention, the patient was finally treated with a combined scraping/use of 20% alcohol and fibrin glue. However, regression of epithelial ingrowth and better visual acuity were only observed some months after the intervention, which shows the importance of waiting for better vision in the postoperative period, thus avoiding new reinterventions.
Assuntos
Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/terapia , Epitélio Corneano/cirurgia , Epitélio Corneano/patologia , Doenças da Córnea/etiologia , Doenças da Córnea/terapia , Ceratomileuse Assistida por Excimer Laser In Situ/efeitos adversos , Recidiva , Reoperação , Adesivo Tecidual de Fibrina , Terapia Combinada , Desbridamento , Etanol/administração & dosagemRESUMO
Platelets have attracted substantial attention in the current decade owing to their unexpected pleiotropic properties and conflicted functions. In fact, platelets participate in both health (hemostasis) and disease (thrombotic diseases). Much of the plasticity of platelets comes from the fact that platelets are the reservoir and the 'natural factory' of growth factors (GFs), with pivotal functions in wound repair and tissue regeneration. By combining the platelets' plasticity and biotechnological processes, PlateInnove Biotechnology optimized the production of GFs in nanoparticle biointerfacing by platelet content, which opens an avenue of possibilities.
Assuntos
Biotecnologia , Plaquetas/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/biossíntese , Biologia Celular , HumanosRESUMO
The Cerrado has a wide diversity of fauna and flora, and the knowledge of its horizontal structure, in different time intervals allows the prediction of its structural and floristic characteristics. The aim of this study was to evaluate the changes in structure and composition of tree community in three fragments of Cerrado with low anthropization, in an interval of 11 years at Minas Gerais state. Rectangular plots of fixed size were sampled, measuring stem diameter and height of all living arboreal individuals with diameter at 1.30 meters above ground (DBH) ≥ 5 cm. The tree vegetation dynamics study of the areas was performed, as well as the floristic analysis and the diametric structure. Considering all fragments and years of measurement, the recruitment of trees surpassed its mortality. The basal area varied between 3.67 and 13.07 m².ha-1. The studied areas, considering all fragments and years of measurement, showed a Shannon diversity index (H') from 3.43 to 3.87 nat.ind-1 and Pielou equitability index (J') ranged an interval between 0.77 and 0.82. The similarity calculated by the Jaccard index (J), when performed per plot considering the three fragments, showed a value of 0.2653. Also, related to the development and growth of the study areas, it can be inferred that all fragments and their respective years of measurement had a J-inverse pattern. In conclusion, it can be inferred that the three fragments maintained a representative growth in number of individuals and basal area.(AU)
Assuntos
Pradaria , Estruturas Vegetais/química , Monitoramento AmbientalRESUMO
The Cerrado has a wide diversity of fauna and flora, and the knowledge of its horizontal structure, in different time intervals allows the prediction of its structural and floristic characteristics. The aim of this study was to evaluate the changes in structure and composition of tree community in three fragments of Cerrado with low anthropization, in an interval of 11 years at Minas Gerais state. Rectangular plots of fixed size were sampled, measuring stem diameter and height of all living arboreal individuals with diameter at 1.30 meters above ground (DBH) ≥ 5 cm. The tree vegetation dynamics study of the areas was performed, as well as the floristic analysis and the diametric structure. Considering all fragments and years of measurement, the recruitment of trees surpassed its mortality. The basal area varied between 3.67 and 13.07 m².ha-1. The studied areas, considering all fragments and years of measurement, showed a Shannon diversity index (H') from 3.43 to 3.87 nat.ind-1 and Pielou equitability index (J') ranged an interval between 0.77 and 0.82. The similarity calculated by the Jaccard index (J), when performed per plot considering the three fragments, showed a value of 0.2653. Also, related to the development and growth of the study areas, it can be inferred that all fragments and their respective years of measurement had a J-inverse pattern. In conclusion, it can be inferred that the three fragments maintained a representative growth in number of individuals and basal area.
Assuntos
Estruturas Vegetais/química , Monitoramento Ambiental , PradariaRESUMO
Bone defects created after curettage of benign bone tumors are customarily filled with solid poly(methyl methacrylate) (PMMA) or other bone substitutes. In this study, we depicted a porous PMMA-based cement (produced by mixing sodium bicarbonate and citric acid) and evaluated the prospect of its clinic application. Cement samples were characterized by high-performance liquid chromatography (HPLC) coupled to mass spectrometry and its cytotoxicity evaluated in fibroblast cultures. Implantation in rabbits allowed the histologic analysis of bone, kidneys, and liver for toxicity and coagulation tests, and MRI images for hemostasis evaluation. Osseointegration was analyzed through radiography, microtomography (micro-CT), SEM, and histology of sheep specimens. Rabbit specimens were analyzed 1, 4, and 7 days after implantation of porous or solid bone cement in 6.0 mm femoral defects. Sheep specimens were analyzed 3 and 6 months after implantation or not of porous or solid cement in 15.0 mm subchondral tibial defects. The production process did not release any detectable toxic substance but slightly reduced fibroblast proliferation in vitro. Until 7 days after surgery, no local or systemic alterations could be detected in histology, or hematoma formation in histology or MRI. Sheep implants showed 6 mm linear ingrowth from the bone-cement interface and 20% bone ingrowth considering the whole defect area. Radiography, micro-CT, SEM, and histology confirmed these findings. We conclude that our porous PMMA-based cement is an attractive alternative treatment for bone defect filling that combines osseointegration and early weight bearing. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 649-658, 2018.
Assuntos
Cimentos Ósseos/farmacologia , Substitutos Ósseos/farmacologia , Osseointegração/efeitos dos fármacos , Polimetil Metacrilato/farmacologia , Animais , Cimentos Ósseos/química , Substitutos Ósseos/química , Transplante Ósseo , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Ácido Cítrico/química , Ácido Cítrico/farmacologia , Modelos Animais de Doenças , Humanos , Rim/efeitos dos fármacos , Fígado/efeitos dos fármacos , Masculino , Camundongos , Células NIH 3T3 , Polimetil Metacrilato/química , Porosidade , Coelhos , Ovinos , Bicarbonato de Sódio/química , Bicarbonato de Sódio/farmacologiaRESUMO
Objetivo: Describir el uso de adhesivo tisular de fibrina para el sellamiento del flap en el tratamiento de un paciente con endocrecimiento epitelial severo posterior a Laser In Situ Keratomileusis (LASIK). Diseño: Reporte de caso. Metodología: Reporte de Caso retrospectivo, mediante la recopilación de datos clínicos, imágenes, video y valoraciones postoperatorias. Resultado: Se reporta el uso de adhesivo tisular para el sellamiento del flap en el tratamiento de un paciente con endocrecimiento epitelial severo bilateral posterior a LASIK. Se documenta la recuperación de la agudeza visual en el ojo izquierdo (el ojo tratado) posterior a el uso de adhesivo tisular de fibrina para el sellamiento del flap en el tratamiento del endocrecimiento epitelial severo posterior a LASIK, llegando a una visión mejor corregida de 20/30. Conclusión: Se han descrito varias opciones de manejo: remoción mecánica junto con adhesión del flap mediante sutura, cianoacrilato, adhesivo tisular de fibrina o hidrogel. En la literatura mundial hay publicaciones de casos sobre el uso de adhesivo tisular de fibrina con buenos resultados, hasta la fecha este es el primer caso reportado en nuestro país, siendo demostrativo de buenos resultados, en cuanto a la tasa de recidiva y agudeza visual.
Purpose: To describe the use of fibrin adhesive for flap sealing in the treatment of a patient with severe epithelial ingrowth following Laser In Situ Keratomileusis (LASIK). Design: Case Report. Methods: Retrospective Case Report study, was performed by collecting clinical data, images, video and postoperative evaluations. Results: The use of tissue adhesive for flap sealing is reported in the treatment of a patient with severe bilateral epithelial ingrowth post-LASIK Subsequent recovery of the visual acuity in the left eye (treated eye) after the use of fibrin adhesive for fl ap sealing in the treatment of severe epithelial post-LASIK epithelial ingrowth, reaching a better-corrected vision of 20/30. Conclusion: Several management options have been described: mechanical removal along with flap adhesion by suture, cyanoacrylate, fibrin adhesive or hydrogel. In the world literature there are case reports on the use of fibrin adhesive with good results, to date this is the fi rst case reported in our country, demonstrating good results in terms of relapse rate and visual acuity.
Assuntos
Doenças da Córnea , Oftalmopatias , Terapia a Laser , Procedimentos Cirúrgicos OftalmológicosRESUMO
Local changes caused by dams can have drastic consequences for ecosystems, not only because they change the water regime but also the modification on lakeshore areas. Thus, this work aimed to determine the changes in soil moisture after damming, to understand the consequences of this modification on the arboreal community of dry forests, some of the most endangered systems on the planet. We studied these changes in soil moisture and the arboreal community in three dry forests in the Araguari River Basin, after two dams construction in 2005 and 2006, and the potential effects on these forests. For this, plots of 20m x10m were distributed close to the impoundment margin and perpendicular to the dam margin in two deciduous dry forests and one semi-deciduous dry forest located in Southeastern Brazil, totaling 3.6ha sampled. Besides, soil analysis were undertaken before and after impoundment at three different depths 0-10, 20-30 and 40-50cm. A tree minimum DBH of 4.77cm community inventory was made before T0 and at two T2 and four T4 years after damming. Annual dynamic rates of all communities were calculated, and statistical tests were used to determine changes in soil moisture and tree communities. The analyses confirmed soil moisture increases in all forests, especially during the dry season and at sites closer to the reservoir; besides, an increase in basal area due to the fast growth of many trees was observed. The highest turnover occurred in the first two years after impoundment, mainly due to the higher tree mortality especially of those closer to the dam margin. All forests showed reductions in dynamic rates for subsequent years T2-T4, indicating that these forests tended to stabilize after a strong initial impact. The modifications were more extensive in the deciduous forests, probably because the dry period resulted more rigorous in these forests when compared to semideciduous forest. The new shorelines created by damming increased soil moisture in the dry season, making plant growth easier. We concluded that several changes occurred in the T0-T2 period and at 0-30m to the impoundment, mainly for the deciduous forests, where this community turned into a riparian-deciduous forest with large basal area in these patches. However, unlike other transitory disturbances, damming is a permanent alteration and transforms the landscape to a different scenario, probably with major long-term consequences for the environment.
Los cambios locales provocados por las represas pueden tener consecuencias para un ecosistema, ya que no solo cambian el régimen de las aguas, sino que también modifican las áreas a la orilla de los lagos. Por lo tanto, este trabajo tuvo como objetivo observar los cambios en la humedad del suelo después de la construcción de represas, para entender las consecuencias de esta modificación a la comunidad arbórea de los bosques secos, que son uno de los sistemas más amenazados del planeta. Después de la construcción de tres represas, se estudiaron los cambios en la humedad del suelo y la comunidad arbórea en 3 bosques secos de la cuenca del río Araguari, en donde se construyeron dos represas en 2005 y 2006. Se demarcaron parcelas de 20x10m que se distribuyeron cerca y perpendicular al margen de la represa en dos bosques secos caducifolios y un bosque seco semideciduo ubicado en el sureste de Brasil, en total se muestrearon 3.6 hectáreas. Se realizó un análisis de la humedad del suelo antes y después de la construcción del embalse en tres profundidades 0-10, 20-30, 40-50cm. El inventario de la comunidad arbórea DAP de 4.77cm se realizó antes T0, dos T2 y cuatro T4 años a partir de la retención del agua. Además se calcularon las tasas anuales dinámicas de todas las comunidades, y se utilizaron pruebas estadísticas para confirmar los cambios en la humedad del suelo y las comunidades de árboles. Los análisis confirmaron aumento de humedad del suelo en todos los bosques, especialmente durante la estación seca y en los lugares más cercanos al embalse, con un aumento del área basal debido al rápido crecimiento de muchos árboles. El mayor volumen de modificaciones se produjo en los primeros dos años después de La construcción del embalse, principalmente debido a la mayor mortalidad de los árboles más cerca del margen de la represa. Sin embargo, todos los bosques mostraron reducción de las tasas dinámicas en los años siguientes T2-T4, lo que indica que estos bosques tienden a estabilizarse después de un fuerte primer impacto. Las modificaciones fueron más severas en los bosques caducifolios, probablemente debido a una estación seca más severa en estos bosques en comparación con el semideciduo. Las nuevas márgenes creadas por el embalse aumentaron la humedad del suelo en la época seca facilitando el crecimiento de muchas plantas. Se concluye que los cambios que se produjeron en el período de T0-T2 y de 0-30m del embalse, principalmente en los bosques caducifolios estan transformando estas comunidades en bosque de ribera-caducifolia con gran área basal en estos parches. Sin embargo, este impacto es diferente a otras alteraciones transitorias, así la construcción del embalse es un cambio permanente y transforma el paisaje en otro escenario, probablemente con importantes consecuencias a largo plazo para el ambiente.