Thoracoscopic-assisted diaphragmatic hernia repair using a thoracic rib resection.

OBJECTIVE: To describe the surgical treatment of a dorsal diaphragmatic hernia in an adult horse using thoracic rib resection aided by thoracoscopy and a flank incision. STUDY DESIGN: Case report. ANIMAL POPULATION: One client-owned horse. RESULTS: A six-year-old Dutch warmblood gelding was admitted for colic-associated colonic incarceration in a diaphragmatic hernia. Seven weeks after the initial colic surgery, the gelding underwent surgery to repair the defect. Thoracoscopy and a flank incision were used to identify the location of the hernia and the subsequent site of rib resection. The stomach was adhered to the edges of the defect, leaving only a small residual hole. Resection of the 14th rib provided excellent exposure of the defect and closure of the remaining hernia. CONCLUSION AND CLINICAL RELEVANCE: Thoracic rib resection can provide access to diaphragmatic hernias in adult horses. Thoracoscopy or a flank incision, or both, may aid in determining which rib is best resected.

Hepatoblastoma with erythrocytosis in a young female horse.

A 2.5-year-old female Thoroughbred was examined because of lethargy, anorexia, and weight loss. Analysis of a CBC revealed erythrocytosis and an increase in PCV. Serum biochemical analysis revealed increases in activities of several hepatic enzymes. Ultrasonography revealed hepatomegaly and a heterogeneous appearance of the hepatic parenchyma. The horse did not improve despite supportive care, and it was euthanatized. Necropsy revealed numerous raised white to gray foci in the liver. Histologically, these foci consisted of neoplastic cells that resembled fetal hepatocytes, embryonal-type cells, and cells with features intermediate between those 2 cell types. Immunohistochemical staining revealed that hepatocytes stained strongly with anti-alpha-fetoprotein. On the basis of these results, hepatoblastoma was diagnosed. Diagnosis of hepatoblastoma is difficult, because it can appear histologically similar to other hepatic tumors, such as hepatocellular carcinomas. Definitive diagnosis requires histologic evaluation of tumor architecture and cell morphology. Immunohistochemical staining for alpha-fetoprotein in tumor cells may serve as a tumor marker but is not pathognomonic of hepatoblastoma. Paraneoplastic syndromes, such as erythrocytosis, can accompany hepatoblastoma. The prognosis for horses with hepatoblastoma is grave.

Mechanism of BMP-2 stimulated adhesion of osteoblastic cells to titanium alloy.

Cell adhesion is dependent on many factors, including the repertoire of extracellular matrix (ECM) proteins and their receptors, e.g. integrins, synthesized by the cell, the composition of the ECM adsorbed to the surface, and the intrinsic chemistry of the surface. Factors that govern bone cell, i.e. osteoblast, adhesion and ECM elaboration significantly influence its re-modeling into mature bone, and ultimately its ability to integrate with biomaterials used for orthopedic prostheses. In this study, we have investigated how treatment with bone morphogenetic protein-2 (BMP-2), a member of the transforming growth factor-beta (TGF-beta) superfamily that promotes ectopic bone formation, modulates the organization and expression of osteoblastic cell proteins. Specifically, we analyzed how BMP-2 treatment affects cytoskeletal components, ECM, and alpha 5 and beta 1 integrin receptor subunits in osteoblastic cells plated on Ti6A14V, a titanium alloy widely used for orthopedic implants that interacts with bone cells in vitro and in vivo. Osteoblastic cells were pre-treated with BMP-2 for 12 h prior to plating; BMP-2 treatment stimulated adhesion and proliferation of osteoblastic cells and this adhesive advantage was reflected in enhanced long-term matrix mineralization in the BMP-2 pretreated cultures. Confocal laser scanning microscopic analysis of BMP-2 treated cells showed that enhanced cytoskeletal organization and focal contact formation occurred. These changes were accompanied by a concomitant increase in the spatial organization of fibronectin, whereas vitronectin, collagen type I, osteopontin, and osteocalcin showed little change. The changes in ECM organization correlated with increased fibronectin, alpha 5 and beta 1 integrin subunit, and focal adhesion kinase (p125FAK) expression, as well as increased p125FAK phosphorylation. By confocal microscopy, the alpha 5 integrin subunit was more concentrated in lamellipodia after BMP-2 treatment. These results demonstrate that BMP-2 significantly altered osteoblastic cytoskeletal and ECM organization and enhanced expression of fibronectin and of specific integrin receptor subunits, with concomitant changes in the levels and phosphorylation of p125FAK. These effects may contribute to downstream cellular responses important for bone cell function, and growth.