Repair of lamellar scleral lesions in dogs with preserved equine renal capsule: short report

OBJETIVO: Avaliar o uso da cápsula renal de eqüino preservada em glicerina 98% no reparo de lesões lamelares esclerais em cães. MÉTODOS: Foram utilizados 12 cães, machos e fêmeas, com peso médio de 12kg. Foram realizadas avaliações clínica e morfológica aos 1, 3, 7, 15, 30 e 60 dias de pós-operatório. Após anestesia geral e procedimentos padrões de preparo do campo operatório, foi realizada cantotomia temporal, seguida de incisão conjutival e escleral com área de 0,5x0,5 cm na posição de 1hora, próxima ao limbo. em seguida, um fragmento de mesma dimensão de cápsula renal de eqüino preservada em glicerina, previamente hidratado em solução salina, foi aplicado ao defeito escleral criado sendo fixado com pontos simples isolados com vicryl 7-0®. RESULTADOS: A avaliação clínica revelou blefaroespasmo/fotofobia até o sétimo dia de pós-operatório. Foi observado edema conjuntival até o quinto dia, acompanhado de secreção ocular mucóide, que persistiu até o décimo dia de pós-operatório. Não foram observados sinais clínicos de rejeição do enxerto em todos os animais, em todos os períodos avaliados. Os segmentos anterior e posterior do bulbo ocular não apresentaram sinais de inflamação. A análise morfológica revelou exsudação inflamatória aguda nos períodos precoces e intermediários da avaliação e inflamação crônica nos períodos tardios da observação. Houve incorporação do enxerto ao leito receptor. CONCLUSÃO: Os resultados sugerem que a cápsula renal de eqüino preservada pode ser mais uma alternativa de membrana biológica para o reparo de lesões esclerais lamelares em cães e no homem.

Mechanism of anticlastogenicity of Agaricus blazei Murill mushroom organic extracts in wild type CHO (K-1) and repair deficient (xrs5) cells by chromosome aberration and sister chromatid exchange assays

Agaricus blazei Murill is a medicinal mushroom native to Brazil. The present work assessed the clastogenic and anticlastogenic potential of organic extracts (ethanol and chloroform/methanol) from the lineage AB97/11 in chinese hamster CHO-K-1 (wild type) and CHO-xrs5 (repair deficient) cells using the chromosome aberration (CA) and sister chromatid exchange (SCE) assays. In these experimental conditions were observed: (a) anticlastogenic effect at concentrations of 0.06 and 0.09% of the EtOH extract and at the 0.03 and 0.06% concentrations of the C/MetOH extract in CHO-K-1; (b) absence of protector effect on CHO-xrs5 cells; and (c) absence of protector effect in the SCE assay. These results indicate that organic extracts of A. blazei lineage AB97/11 present bio-antimutagenic type protective activity. (C) 2003 Elsevier B.V. B.V. All rights reserved.

Considerations on corrosion and weld repair effects on the fatigue strength of a steel structure critical to the flight-safety

The aim of this study is to analyze the effects of corrosion and successive tungsten inert gas (TIC) welding repairs on the reverse bending fatigue strength of AISI 4130 steel used in components critical to the flight-safety. The tests were performed on hot-rolled steel plate specimens, 1.10 mm and 1.60 mm thick, by means of a SCHENK PWS equipment, with load ratio R = -1, constant amplitude, 30 Hz frequency and room temperature. It was observed that the reverse bending fatigue strength of AISI 4130 steel decreases due to the corrosion and the TIC welding and re-welding processes. (C) 2010 Elsevier Ltd. All rights reserved.

Repair Welding Effects on the Bending Fatigue Strength of AISI 4130 Aeronautical Steel used in a Critical to the Flight-Safety Structure

The aim of this study was to analyze the effect of successive TIG (tungsten inert gas) welding repairs on the reverse bending fatigue strength of AISI 4130 steel, which is widely used in components critical to the flight-safety. In order to simulate the abrupt maneuvers, wind bursts, motor vibration and helixes efforts, which generate cyclic bending loadings at the welded joints of a specific aircraft component called motor cradle, experimental reverse bending fatigue tests were carried out on specimens made from hot-rolled steel plate, 1.10 mm (0.043 in) thick, by mean of a SCHENK PWS equipment, with load ratio R = -1, under constant amplitude, at 30 Hz frequency and room temperature. It was observed that the bending fatigue strength decreases after the TIG (Tungsten Inert Gas) welding process application on AISI 4130 steel, with subsequent decrease due to re-welding sequence as well. Microstructural analyses and microhardness measurements on the base material, heat-affected zone (HAZ) and weld metal, as well as the effects of the weld bead geometry on the obtained results, have complemented this study.

Considerations about the welding repair effects on the structural integrity of an airframe critical to the flight-safety

Structures critical to the flight-safety are commonly submitted to several maintenance repairs at the welded joints in order to prolong the in-service life of aircrafts. The aim of this study is to analyze the effects of Tungsten Inert Gas (TIG) welding repair on the structural integrity of the AISI 4130 aeronautical steel by means of experimental fatigue crack growth tests in base-material, heat-affected zone (HAZ) and weld metal. The tests were performed on hot-rolled steel plate specimens, 0.89 mm thick, with load ratio R = 0.1, constant amplitude, at 10 Hz frequency and room temperature. Increase of the fracture resistance was observed in the weld metal but decreasing in the HAZ after repair. The results were associated to microhardness and microstructural changes with the welding sequence. (C) 2010 Published by Elsevier Ltd.

Comparative study between two techniques of incisional hernia repair with polypropylene mesh in rabbits

OBJETIVO: Comparar duas técnicas de tratamento da hérnia incisional em coelhos utilizando a tela de polipropileno apoiando um reforço peritônio - aponeurótico ou suturada nas bordas do anel herniário 'em ponte . MÉTODOS: Foram operados 60 coelhos para a produção de hérnia incisional, em uma incisão mediana de 4 centímetros. Após 30 dias, metade dos animais foram operados com o fechamento primário da parede, com colocação de uma tela de polipropileno apoiando o reforço e a outra metade dos animais com a colocação da tela suturada nas bordas do anel herniárioem ponte . Os animais foram avaliados com 30 (M1), 60 (M2)e 90 (M3) dias de pós-operatório. Os parâmetros analisados foram a evolução clínica, análise da força de ruptura da cicatriz, estudo macroscópico, análise microscópica e morfométrica. RESULTADOS: Não foram observadas diferenças significantes com relação a força de ruptura e estudos histológicos nos dois grupos e vários momentos estudados. Não houve diferença estatística com relação às complicações, embora os animais que receberam a telaem ponte tiveram aderências mais firmes e intensas à parede abdominal. CONCLUSÕES: As duas técnicas utilizadas para correção da hérnia incisional em coelhos não mostraram diferenças significantes quanto a força de ruptura, análise histológica e morfométrica. O número de complicações foi semelhante, porém a aderência de órgãos da cavidade abdominal à área de cicatriz foi muito mais intensa no grupo em que a tela foi colocadaem ponte .

Repair of the anophthalmic cavity of rats with synthetic hydroxyapatite

We placed spheres of synthetic hydroxyapatite (calcium chloride combined with sodium phosphate) in the eviscerated or enucleated orbital cavity of rats in order to evaluate the biocompatibility of this material with the orbital cavity. The study was conducted on 50 albino rats, 25 of which were submitted to enucleation and 25 to evisceration of one eye. The animals were sacrificed 7, 15, 21, 30 and 60 days after surgery and the orbital content was submitted to histopathological examination. A reaction of the young granulation tissue type was observed first. The hydroxyapatite was gradually surrounded by a granulomatous macrophage inflammatory response and covered with dense connective tissue that formed a sort of mesh septating and supporting progressively smaller blocks of the substance. The same type of reaction was observed in the enucleated and eviscerated cavities. We conclude that synthetic hydroxyapatite is an inert nonallergenic material which is appropriate for volume replacement in the anophthalmic cavity

Vegetal polymer in repair of defects of the orbital floor: an experimental study in rabbits

Background: An experimental study was done to assess the ability of the vegetal polymer miniplates and screws to repair defects of the orbital floor.Methods: An artificial standard-sized defect was created in the bony floor of right orbit of 45 albino rabbits. The animals were divided into three experimental groups: control group (G1) involving animals with orbital floor defect and no treatment; titanium group (G2) containing animals with orbital floor defect repaired by titanium miniplates and screws; vegetal polymer group (G3) composed of animals with similar orbital floor defects repaired by vegetal polymer miniplates and screws. Throughout the course of the experiment, the animals were clinically evaluated. At 15, 30 and 60 days after surgery, the animals were killed. They were X-rayed immediately after the floor defect and at the moment of sacrifice. Histological and morphometric evaluation of inflammatory reaction and bone healing was done. Data were statistically evaluated.Results: No implants were extruded. Bone consolidation was similar in G2 and G3 and better than in G1 group animals. Inflammatory reaction was most pronounced in animals of G3 15 days after surgery, and it subsided over time.Conclusion: Vegetal polymer miniplates and screws induces small inflammatory reaction and had the ability to stimulate bone growth with good integration in the orbital floor defect allowing to consider the vegetal polymer adequate option to treat orbital floor defects. Future studies involving long-term follow-up and biomechanical tests to evaluate material resistance to traction are needed.

In vivo and in vitro evaluation of an Acetobacter xylinum synthesized microbial cellulose membrane intended for guided tissue repair

Background: Barrier materials as cellulose membranes are used for guided tissue repair. However, it is essential that the surrounding tissues accept the device. The present study histologically evaluated tissue reaction to a microbial cellulose membrane after subcutaneous implantation in mice. Furthermore, the interaction between mesenchymal stem cells and the biomaterial was studied in vitro to evaluate its ability to act as cellular scaffold for tissue engineering.Methods: Twenty-five Swiss Albino mice were used. A 10 x 10 mm cellulose membrane obtained through biosynthesis using Acetobacter xylinum bacteria was implanted into the lumbar subcutaneous tissue of each mouse. The mice were euthanatized at seven, 15, 30, 60, and 90 days, and the membrane and surrounding tissues were collected and examined by histology.Results: A mild inflammatory response without foreign body reaction was observed until 30 days post-surgery around the implanted membrane. Polarized microscopy revealed that the membrane remained intact at all evaluation points. Scanning electron microscopy of the cellulose membrane surface showed absence of pores. The in vitro evaluation of the interaction between cells and biomaterial was performed through viability staining analysis of the cells over the biomaterial, which showed that 95% of the mesenchymal stem cells aggregating to the cellulose membrane were alive and that 5% were necrotic. Scanning electron microscopy showed mesenchymal stem cells with normal morphology and attached to the cellulose membrane surface.Conclusion: The microbial cellulose membrane evaluated was found to be nonresorbable, induced a mild inflammatory response and may prove useful as a scaffold for mesenchymal stem cells.

Influence of diet on oxidative DNA damage, uracil misincorporation and DNA repair capability

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Two Surgical Approaches to Fracture Malunion Repair

Two birds were presented with malunion fractures. The first was a young toco toucan (Ramphastos toco) with malunion of the tarsometatarsus that was treated by an opening-corrective osteotomy and an acrylic-pin external skeletal fixator (type II) to stabilize the osteotomy. The second bird was m adult southern caracara (Caracara plancus) with radial and ulnar malunion that was treated by closing-wedge osteotomies. Stabilization of the osteotomy sites was accomplished through 1 bone plate fixed cranially on the ulna with 6 cortical screws and an interfragmentary single wire in radius. In both cases, the malunion was corrected, but the manus of the southern caracara was amputated because of carpal joint luxation that induced malposition of the feathers.

Miniplate fixation for the repair of segmental mandibular defects filled with autogenous bone in cats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Miniplate 1.5 fixation for the repair of mandibular osteotomies in cats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of alveolex on the bone defects repair stimulated by rhBMP-2: Histomorphometric study

OBJECTIVE: The aim of this study was to evaluate histomorphometrically the effect of alveolex (Propolis 10%) on the repair of bone cavities in the calvaria of rats. MATERIALS and METHODS: A 5 mm diameter bone defect was made in the calvaria of male Wistar rats using the drill-type trephine. The defects were filled with rhBMP-21Alveolex, rhBMP-2, Alveolex, or coagulum. Twenty-eight animals with seven subjects on each were sacrificed 30 days after surgery and samples were fixed and embedded in paraffin. Histological sections stained by HE (hematoxylin and eosin) were obtained from the calvaria bone defect and analyzed by a differential point-counting method. RESULTS: Group I and II, rhBMP-21Alveolex and rhBMP-2, respectively, presented higher levels of newly formed bone than other groups (P < 0.001). There were not significant differences between groups I and II (P > 0.05). In addition, there was not significant difference between groups III and IV, Control-Coagulum and Alveolex, respectively (P > 0.05). CONCLUSION: Alveolex has increased the bone repair in calvaria defects of rats when associated to rhBMP-2, however without significant differences for rhBMP-2 isolated group; Alveolex isolated group showed the lowest levels of newly formed bone with no significant differences to coagulum group (control). Microsc. Res. Tech. 75: 36-41, 2012. (C) 2011 Wiley Periodicals, Inc.