Vascular endothelial growth factor and its receptor, FIk-1/KDR, are cytoprotective in the extravascular compartment of the ovarian follicle

Vascular endothelial growth factor (VEGF) is a potent mitogen and cytoprotective factor for vascular endothelial cells. Although VEGF is ubiquitously expressed, its role in nonvascular tissues is poorly understood. VEGF interacts with various cell surface receptors to mediate its cellular effects. It previously has been thought that the VEGF receptor Flk-1/ KDR, its main signaling receptor, was expressed exclusively by endothelial cells. However, in the present study using bovine and rodent models, we demonstrate that VEGF and Flk-1/KDR are coexpressed in ovarian granulosa cells. VEGF and Flk-1/KDR mRNA and protein were both detectable in follicle tissue sections and in vitro cultured granulosa cells. Expression of both ligand and receptor increased in healthy follicles throughout follicular development. VEGF treatment of serum-starved and cytokine-exposed granulosa cells resulted in enhanced survival, and this cytoprotection was ameliorated when Flk-1/KDR signaling was inhibited. Reduced expression of Flk-1/KDR was also associated with the onset and progression of follicle atresia, suggesting involvement in follicular health in vivo. The results of this study demonstrate for the f

Punção aspirativa por agulha fina como método de coleta de material para a histopatologia no osteossarcoma canino

Para a obtenção do diagnóstico definitivo do osteossarcoma realizam-se exames citopatológico e histopatológico. O material para exame citopatológico é coletado através de punção aspirativa por agulha fina (PAAF), já para a realização do exame histopatológico é necessário uma amostra de tamanho maior, geralmente conseguida através de biópsia incisional. Este trabalho tem como objetivo desenvolver uma técnica de coleta de material em cães com suspeita de osteossarcoma através de PAAF para a realização de exame histopatológico. Foram coletadas duas amostras de 12 cães suspeitos de osteossarcoma por PAAF. O material obtido pela primeira coleta foi utilizado para confirmar o diagnóstico através do exame citopatológico, enquanto que o material oriundo da segunda coleta foi fixado em formol a 10% para a análise histopatológica. Quatro das 12 amostras (33,3%) avaliadas histopatologicamente pela metodologia proposta obtiveram também o diagnóstico de osteossarcoma. Esses resultados apontam para uma possível adequação da técnica de coleta de material por PAAF para exame histopatológico.<br>Cytopathologic and histopathologic tests are important to obtain a definitive diagnosis of osteosarcoma. The sample for cytopathological exam is collected through fine-needle aspiration cytology (FNA). On the other hand, histopathological exams need a larger sample that is usually obtained by incisional biopsy. The objective of this article is to develop a FNA technique to biopsy and evaluate histopatologically samples of dogs with suspected osteosarcoma. Two FNS samples were collected from 12 such dogs. Samples obtained in the first procedure were examined cytologically. The material sampled at the second biopsy was fixed in 10% formalin and submitted to histopathological analysis. Four out of the 12 samples (33.3%) examined by the herein proposed method were diagnosed as osteosarcoma. These results indicate a possible adaptation of FNA for histopathological examination