Tubo de ácido poliglicólico e GM1 na regeneração de nervos periféricos

INTRODUÇÃO: A auto-enxertia de nervo é considerada tratamento de escolha nas grandes perdas de tecido neural que não permitam a reparação através de anastomose primária. Nesses casos, o tubo sintético à base de ácido poliglicólico é uma alternativa para enxertia de nervo. Por outro lado, muitos estudos têm enfatizado a importância dos fatores neurotróficos na regeneração neural: o monossialotetraesosilgangliosídeo (GM1), um dos principais glicoesfingolípides do tecido nervoso de mamíferos, é tido como potencializador dos efeitos desses fatores. OBJETIVO: Comparar, em ratos, o grau de regeneração neural, utilizando análise histológica, contagem do número de axônios mielinizados regenerados e análise funcional com a utilização do neurotubo e do GM1. MÉTODOS: Essa avaliação foi obtida com a interposição de enxerto autógeno (grupo A), tubo de ácido poliglicólico (grupo B) e da associação do tubo de ácido poliglicólico à administração de GM1 (grupo C) em defeitos de 5 mm no nervo ciático. RESULTADOS: Foi observada formação de neuroma apenas no grupo A. Os grupos A e C apresentaram padrões histológicos semelhantes, exceto que os axônios regenerados do grupo C apresentavam-se mais organizados e mielinizados que o grupo A. CONCLUSÃO: Na recuperação funcional, não houve diferença estatisticamente significativa entre os três grupos, a despeito das diferenças histológicas qualitativas e quantitativas verificadas.

Therapeutic Option for Infected Urinary Tract Fistulas in Renal Transplantation

Background. Approximately 20% of urinary tract fistulas after renal allografting are complicated by urinary tract infection, which presents a therapeutic challenge. Objective. To evaluate an option for treatment of urinary tract fistulas associated with urinary tract infection and unsuitable for minimally invasive or primary surgical urinary tract repair. Patients and Methods. The study included 650 recipients who underwent transplantation over 17 years. Urinary leakage was initially treated with indwelling bladder catheterization. Patients with fistulas refractory to treatment underwent surgical intervention to repair the urinary tract. In patients who were not candidates for primary repair of the urinary tract, temporary urinary diversion was performed, rather than classic percutaneous or open nephrostomy, using a ureteral stent (ie, a 6F or 8F Foley catheter with the balloon placed inside the renal pelvis). Results. Overall, urinary leakage occurred in 36 patients (5.5%). Conservative management was successful in 14 vesical fistulas (42.4%) and no ureteral fistulas (0%). Three patients died of sepsis during conservative treatment, before the new surgical approach. Five of 36 urinary leaks (13.9%) were managed using ureteral intubation with an 8F Foley catheter, with a success rate of 80%. Conclusion. Ureteral catheterization with an 8F Foley catheter is a feasible therapeutic option to treat complicated urinary tract fistulas unsuitable for primary surgical repair of the urinary tract.

POLYGLYCOLIC ACID TUBE ASSOCIATED WITH GM1 IN REGENERATION OF PERIPHERAL NERVES

Introduction: Nerve allografting is regarded as a treatment of choice in large neural tissue losses preventing repair by primary anastomosis. In these cases, a synthetic polyglycolic acid tube is an alternative for nerve grafting. On the other hand, several studies have emphasized the importance of neurotrophic factors on neural regeneration, including substances with potential to optimize neural regeneration, especially the GM1, an neurotrophic enhancer factor. Objective: to compare, in rats, the neural regeneration degree using histological analysis, regenerated myelinized axons count, and functional analysis with the use of neurotube and GM1. Methods: This assessment was performed by interposing allograft (group A), polyglycolic acid tube (group B) and polyglycolic acid tube associated to GM1 (group C) on 5-mm sciatic nerve defects. Results: Neuroma formation was found only on group A. Groups A and C showed similar histological patterns, except for the regenerated axons on group C, which were shown to be better organized and myelinized than in group A. Conclusion: on functional recovery, no statistically significant difference was found for the three groups, despite of qualitative and quantitative histological differences found.