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The purpose of this study was to evaluate a suitable animal model for the in vivo evaluation of patency and vascular tissue regeneration in small intestinal submucosa (SIS) vascular grafts for hemodialysis access. First, a 4-mm U-shaped SIS vascular graft was implanted between the internal carotid artery (CA) and the external jugular vein (JV) in five sheep and six swine. The U-shape grafts remained functional for 53 ± 4 days in sheep and 32 ± 2 days in swine. The sheep model presented exaggerated inflammation, so the swine model was selected for the in vivo study. Based on these initial results, a 4-mm C-shape SIS vascular graft with SIS circumferential reinforcement was developed to mechanically improve the vascular graft and manage complications identified during surgery in both sheep and swine. The C-shape vascular graft was implanted in a swine model (n = 3) between the CA and JV. GORE-TEX® vascular grafts were used as controls in the contralateral side of the neck. C-shape grafts remained patent for 47 ± 4 days, whereas the GORE-TEX® grafts were patent for 30 ± 15 days. The C-shape vascular graft was easier to handle during surgery, and its circumferential reinforcement improved in vivo patency, avoiding kinks in the graft after implantation. Histological results showed neovascularization and some regeneration with the alignment of endothelial cells in the vascular wall of the grafts. The model developed may be helpful in other research involving in vivo studies of vascular grafts for hemodialysis access.

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Liver transplantation is the only available treatment for some patients with end-stage liver disease. Despite reduction in mortality rates due to advances related to surgical techniques, intensive medical management and immunosuppressive therapy, invasive fungal infections remain a serious complication in orthotopic liver transplantation. We report the case of an 18-year-old male diagnosed with autoimmune cirrhosis in 2009 who was assessed and listed for liver transplantation for massive variceal hemorrhage. One year after listing a successful orthotopic liver transplantation was performed. Uneventful early recovery was achieved; however, he developed pulmonary and neurological Aspergillus infection 23 and 40 days after surgery, respectively. Antibiotic therapy with voriconazole and amphotericin was started early, with no major response. Neuroimaging revealed multiple right frontal and right parietal lesions with perilesional edema; surgical management of the brain abscesses was performed. A biopsy with periodic acid-Schiff and Gomori stains revealed areas with mycotic microorganisms morphologically consistent with Aspergillus, later confirmed by culture. The patient developed necrotizing encephalitis secondary to aspergillosis and died. Necrotizing encephalitis as a clinical presentation of Aspergillus infection in an orthotopic liver transplant is not common, and even with adequate management, early diagnosis and prompt antifungal treatment, mortality rates remain high.