Pionefrose unilateral em cão - relato de caso / Unilateral pyonephrosis in a dog - case report / Pionefrosis unilateral en perro - relato de caso

A pionefrose consiste em uma hidronefrose contaminada, associada à destruição do parênquima renal. Tem como causas o bloqueio ureteral ou uretral por urólitos, inflamação crônica, neoplasia e ureter ectópico, seguidos de contaminação. O diagnóstico é realizado através de exames de imagem, principalmente a ultrassonografia e também através de urinálise e urocultura. Em casos avançados o tratamento preconizado é a nefrectomia. O presente trabalho tem como objetivo relatar um caso de um cão com suspeita inicial de hidronefrose. O paciente passou por nefrectomia, no pós-operatório observou-se melhora do seu quadro clínico, porém permanecendo a anemia. O diagnóstico definitivo, realizado por exame histopatológico, revelou pionefrose, entretanto sua causa não foi estabelecida.(AU)

Pyonephrosis consists of a contaminated hydronephrosis associated with the destruction of the renal parenchyma. Its causes include ureter or urethra blockage by uroliths, chronic inflammation, neoplasm, and ectopic ureter, followed by contamination. The diagnosis is made through image exams, mainly ultrasound, and also through urinalysis and uroculture. In advanced cases, nephrectomy is the recommended treatment. The objective of this study is to report a case of a dog with initial suspicion of hydronephrosis. The patient underwent nephrectomy, and during the postoperative period, an improvement in the clinical scenario was observed, despite the persistent anemia. The definitive diagnosis, carried out by histopathological examination, revealed pyonephrosis; however, its cause was not established.(AU)

La pionefrosis es una hidronefrosis contaminada, asociada con la destrucción del parénquima renal. Sus causas son el bloqueo ureteral o uretral por urolitos, inflamación crónica, neoplasia y uréter ectópico, seguido de contaminación. El diagnóstico se realiza mediante exámenes de imágenes, principalmente ultrasonografía y también mediante análisis de orina y urocultivo. En casos avanzados el tratamiento recomendado es la nefrectomía. Este artículo tiene como objetivo informar un caso de un perro con sospecha inicial de hidronefrosis. El paciente se sometió a nefrectomía; después de la operación, su estado clínico mejoró, pero la anemia permaneció. El diagnóstico definitivo realizado por el examen histopatológico reveló pionfrosis, sin embargo, su causa no se ha establecido.(AU)

In vitro evaluation of three different biomaterials as scaffolds for canine mesenchymal stem cells.

PURPOSE: To evaluate in vitro ability the of three different biomaterials - purified hydroxyapatite, demineralized bone matrix and castor oil-based polyurethane - as biocompatible 3D scaffolds for canine bone marrow mesenchymal stem cell (MSC) intending bone tissue engineering. METHODS: MSCs were isolated from canine bone marrow, characterized and cultivated for seven days with the biomaterials. Cell proliferation and adhesion to the biomaterial surface were evaluated by scanning electron microscopy while differentiation into osteogenic lineage was evaluated by Alizarin Red staining and Sp7/Osterix surface antibody marker. RESULTS: The biomaterials allowed cellular growth, attachment and proliferation. Osteogenic differentiation occurred in the presence of hydroxyapatite, and matrix deposition commenced in the presence of the castor oil-based polyurethane. CONCLUSION: All the tested biomaterials may be used as mesenchymal stem cell scaffolds in cell-based orthopedic reconstructive therapy.

In vitro evaluation of three different biomaterials as scaffolds for canine mesenchymal stem cells

PURPOSE: To evaluate in vitro ability the of three different biomaterials - purified hydroxyapatite, demineralized bone matrix and castor oil-based polyurethane - as biocompatible 3D scaffolds for canine bone marrow mesenchymal stem cell (MSC) intending bone tissue engineering. METHODS: MSCs were isolated from canine bone marrow, characterized and cultivated for seven days with the biomaterials. Cell proliferation and adhesion to the biomaterial surface were evaluated by scanning electron microscopy while differentiation into osteogenic lineage was evaluated by Alizarin Red staining and Sp7/Osterix surface antibody marker. RESULTS: The biomaterials allowed cellular growth, attachment and proliferation. Osteogenic differentiation occurred in the presence of hydroxyapatite, and matrix deposition commenced in the presence of the castor oil-based polyurethane. CONCLUSION: All the tested biomaterials may be used as mesenchymal stem cell scaffolds in cell-based orthopedic reconstructive therapy.

Resposta tecidual a implantes de discos de poliuretana de mamona nas formas pré-moldada ou biomassa moldada / Tissue reaction to premolded or molded biomass disks of polyurethanes containing castor oil

O trabalho teve por objetivo avaliar a resposta tecidual à implantação de discos de poliuretana derivada do óleo de mamona confeccionados de duas formas distintas, na forma pré-moldada fornecida pela indústria e em biomassa moldada no momento da aplicação, de forma a observar se haveria algum tipo de reação local tardia associada à possível continuidade do processo de endurecimento final do biomaterial. Foram utilizados 20 ratos, linhagem Wistar, fêmeas, com peso de 300-350g, nos quais foi inserido o disco pré-moldado no tecido subcutâneo do flanco direito e o de biomassa moldada no flanco esquerdo. Ambos os discos tinham 0,8cm de diâmetro por 0,5cm de espessura. Para o procedimento histológico, cinco ratos foram submetidos à eutanásia aos 3, 7, 15 e 30 dias de pós-cirúrgico. Os implantes e tecidos circundantes foram colhidos, processados e corados pela técnica de hematoxilina-eosina. Foi observada inicialmente uma reação inflamatória moderada, composta especialmente por células polimorfonucleares e macrófagos. Os linfócitos variaram de ausentes a discretos. A reação inflamatória diminui de intensidade à medida que se intensificou a formação de tecido conjuntivo fibroso ao redor dos implantes, porém sem modificação dos números de macrófagos. Sendo assim, conclui-se que ambos os discos de poliuretana induzem uma reação inflamatória similar, que varia de moderada a discreta na dependência do momento de avaliação.

The aim of this study was to histologically evaluate the tissue reaction to implantation of polyurethane disks containing castor oil produced in premolded form, supplied commercially, and biomass molded at the moment of application; since a late tissue reaction may occur during the total hardening process of the biomaterial. Twenty female Wistar rats, about 3 months of age, weighing 300-350g, and polyurethane disks 0.8cm in diameter and 0.5cm in thickness were used. The premolded disk was implanted into the subcutaneous tissue at the right flank and the molded biomass disk at the left flank. Five rats each were submitted to euthanasia at 3, 7, 15 and 30 days after surgery, and the polyurethane disks and surrounding tissue were collected. The specimens were processed for HE staining and examined microscopically. A moderate inflammatory reaction was primarily composed of polymorphonuclear cells and macrophages. The lymphocytes varied from absent to discreet. The intensity of the inflammatory reaction decreased at the same time the formation of fibrous conjunctive tissue increased around the implants. However, the numbers of macrophages remained the same. In conclusion, both polyurethane disks induce the same type of inflammatory reaction that varies from slight to moderate according to evaluation time.

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.

Comparison between polyurethanes containing castor oil (soft segment) and cancellous bone autograft in the treatment of segmental bone defect induced in rabbits.

The aim of this study is to compare polyurethanes containing castor oil (soft segment) in granular form compared to cancellous bone autograft applied to a segmental bone defect. Norfolk adult female rabbits - approximately 13 months of age with a mean body weight of 4.5 kg - are used. In both radial diaphyses, 1 cm osteoperiosteal segmental defects are created. The defect in the left radius is filled with the castor-oil-based polyurethane, and the right one, filled with cancellous bone autograft, collected from the left proximal humerus. The rabbits are euthanazed at 15, 30, 60, and 120 days postsurgery (5 animals/ period), for histological analyses. By radiographic analyses, at these time points, the bone regeneration is more evident and accelerated in the bone defects treated with the cancellous bone autograft. At 120 days postsurgery, the segmental bone defects treated with the cancellous bone autograft are totally reconstituted and remodeled, while the bone defects treated with polyurethane polymer have bone formation of 79%. Histological study shows that the polyurethane acts as a space filler, minimizing the local production of fibrous tissue. No granule degradation, resorption or any inflammatory reaction is detected. Thus, it is possible to conclude that the castor-oil-plant-based polyurethane - in the granule presentation - is biocompatible and osteointegrated, but does not show the same bone regeneration capacity as the cancellous bone autograft.