I Propriedades mecânicas de meniscos frescos de coelhos e preservados em glicerina 98%Mechanical properties of the fresh rabbit menisci and of the menisci preserved in glycerin 98%
In the present study was evaluated the effect of 98% glycerin on the collagen fibers, tissue architecture and size of medial meniscuses of New Zealand rabbits. The animals were separated into three groups: (1) Group MF of fresh meniscus, (2) Group MG of meniscus preserved in glycerin for 30 days, and (3) Group MR of meniscus preserved in glycerin for 30 days and rehydrated in NaCl 0.9% for 12 hours. Histological sections were stained with sirius red for identification of collagen types, which were examined with a polarized light microscope. The total collagen concentration and the fiber arrangement were evaluated. Group MF presented higher Type I collagen concentration and lower Type III collagen concentration when compared with Group MG and MR. This fact is due to the water loss and consequent reduction in size and subsequent retraction of the collagen fibers of the meniscus from these groups, caused by dehydration. This may have occurred because those Type I fibers, thicker and in larger quantities, become more evident than Type III collagen fibers, which are more slender and fragile (fibrils). In the three groups studied, the collagen fibers presented themselves in a circumference form, interposed by radially oriented fibers. All of the meniscuses from Group MF presented fibers arranged obliquely, while in the treated groups, a slight disorganization of collagen fibers could be observed in some areas, what corresponds to 42.8% and 14.3% of the meniscuses, respectively. The MG group presented a significant decrease (p<0.05) in size if compared with the MF group. In the MR group, 85.7% of the meniscuses went back to the original size after rehydratation. The 98% glycerin is effective in preserving the meniscus, following rehydratation, maintaining size, structural architecture, integrity and percentage of collagen of the meniscus preserved similar to the fresh one.INDEX TERMS: Allograft, articular cartilage, meniscus.RESUMO.-No presente estudo foi avaliado o efeito da glicerina 98% sobre as fibras colágenas, arquitetura tecidual e o tamanho de meniscos mediais de coelhos da raça Nova Zelândia. Os meniscos foram separados em três grupos: (1) Grupo MF com meniscos frescos (grupo controle), (2) Grupo MG com meniscos preservados em glicerina 98% por 30 dias, e (3) Grupo MR com meniscos preservados em glicerina 98% por 30 dias e reidratados em NaCl 0,9%, por 12 horas. Os cortes histológicos fo-
295Pesq. Vet. Bras. 30(4):295-300, abril 2010 RESUMO.-No presente estudo foi avaliada a arquitetura tecidual, a população celular, assim como a integridade e a distribuição dos tipos celulares em meniscos frescos de coelhos e preservados em glicerina 98%. Foram analisados meniscos mediais de coelhos recém abatidos, que foram distribuídos em três grupos: o grupo MF (n=7), composto por meniscos frescos, correspondeu ao grupo controle; o grupo MG (n=7), composto por meniscos preservados em glicerina 98%, por 30 dias, e o grupo MR (n=7), por meniscos preservados em glicerina 98% e reidratados em NaCl 0,9%, por 12 horas. Em todos os meniscos foram identificados e quantificados os diferentes tipos celulares: fibroblastos/fibrócitos e condrócitos. A população celular foi estatisticamente semelhante nos três grupos de meniscos, sendo que os meniscos preservados, grupos MG e MR, apresentaram menor intensidade de coloração e retração das fibras colágenas, diminuição de volume e maior intensidade de coloração dos núcleos (condensação da cromatina), em relação aos meniscos frescos (MF), caracterizando o fenômeno de lise celular. In the present study was evaluated the tissue architecture, the percentage of cellular population, as well as viability and distribution of cells in fresh menisci of rabbits and preserved in 98% glycerin. Were analyzed medial menisci of rabbits freshly slaughtered, which were distributed into three groups: the MF group (n=7), composed of fresh menisci, corresponded to the control group; the MG group (n=7), composed by menisci preserved in 98% glycerin, for 30 days, and the MR group (n=7) by menisci preserved in 98% glycerin and rehydrated in NaCl 0.9% for 12 hours. In all menisci were identified and quantified the different cell types: fibroblasts/fibrocytes and condrocytes. The cell population percentage was statistically similar in all groups. All menisci preserved in the MG and MR groups showed a lower intensity of color and shrinkage of collagen fibers, reduced volume and higher intensity of staining of nucleus (chromatin condensation), as compared to fresh menisci (MF), featuring the phenomenon of cell lysis. The cartilaginous matrix of preserved menisci proved to be well preserved because the tissue architecture was maintained. It was concluded that 98% glycerin is an optional preservation mean for meniscal allografts with a devitalized collagenous matrix.INDEX TERMS: Articular cartilage, meniscal allograft, knee.
Background: Splenic stromal neoplasms are a heterogeneous group of tumors that shares the morphology of spindle cells, and are considered a primary mesenchymal neoplasm of the spleen. Among these neoplasms, some are as yet unclassified. Although stromal neoplasms represent 25 a 50% of dog splenic neoplasms in dogs, subtypes rarely occur alone. As these neoplasms are difficult to diagnose in the routine veterinary medical examination, the objective of this article was to report a case of splenic stromal sarcoma in a dog treated at a private veterinary hospital in Recife, Pernambuco, Brazil. Case: An 8-year-old male labrador dog was treated at a veterinary hospital for an initial clinical suspicion of gastroenteritis. Clinical examinations showed anemic ocular mucosa and a distended abdomen. Considering the animal’s condition, blood count, serum biochemistry, and abdominal ultrasonography (US) were requested. The laboratory tests revealed anemia, thrombocytopenia, leukocytosis with neutrophilia, and changes in the indices of alanine aminotransferase (ALT) and alkaline phosphatase (ALP), among other findings. Abdominal ultrasound showed hepatomegaly, diffuse splenomegaly, a neoformation in the spleen suggestive of splenic neoplasia, and mild cystic prostatic hyperplasia. The dog underwent exploratory laparotomy with splenectomy. During the procedure, a nodule was found attached to the spleen. It was removed, fixed in a 10% neutral buffered formalin solution, and sent for histopathological and immunohistochemical examinations (vimentin, S100, desmin, MyoD1, HHF35, CD31, and alpha smooth muscle actin). The histopathological diagnosis was poorly differentiated spindle cell splenic sarcoma, compatible with splenic stromal sarcoma. Immunohistochemistry showed neoplastic cells immunoreactive for vimentin and S100, and it was not reactive for other markers. Based on the immunohistochemical and morphological profile, the diagnosis of splenic stromal sarcoma was confirmed. Discussion: Dogs affected by splenic neoplasms are generally aged between three and 17 years, and clinically present withanorexia, emesis, lethargy, weight loss, and abdomen distension, which were observed in the present case. However, a purelyclinical diagnosis is disputable, since other diseases can present the same signs. Thus, complementary exams are essential for a correct diagnosis. Laboratory changes in blood count and serum biochemistry are considered nonspecific for splenic neoplasms, with neutrophilic leukocytosis and anemia being consistent with paraneoplastic syndromes frequently diagnosed in small animals. Microscopically, splenic stromal sarcomas are characterized by focal splenic nodules composed of cohesive polygonal to spindle-shaped cell layers. The cells usually exhibit anisokaryosis and often have large oval to round vesicular nuclei and, occasionally, multinucleated cells. They have large areas of necrosis, diffuse or nodular lymphoid aggregates, and foci of extramedullary hematopoiesis, consistent with the histopathological examination reported in the present case. The immunohistochemical analysis included evaluation of seven markers to elucidate the histogenesis of the neoplasm, with the anti-vimentin and anti-S100 markers demonstrating positive cytoplasmic immunoreactivity, revealing the mesenchymal origin of the neoplasm. Thus, the definitive diagnosis was splenic stromal sarcoma, a rare and aggressive neoplasm. Keywords: spleen, histopathology, immunohistochemistry, neoplasm. Descritores: baço, histopatologia, imunohistoquímica, neoplasia
agrariacad Saculectomia anal em cão pelo método fechado utilizando polietileno -relato de caso. Anal saculectomy in dog by the closed method using polyethylene -case report.
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