Resumo O reparo por excisão de nucleotídeos (NER) atua reparando danos no DNA, como lesões causadas por cisplatina. A proteína Xeroderma Pigmentosum complementation group C (XPC) está envolvida no reconhecimento de danos pela via de reparação global do genoma pelo NER (GG-NER) e tem sido estudada em diferentes organismos devido à sua importância em outros processos celulares. Neste trabalho, estudamos proteínas do NER em Trypanosoma cruzi e Trypanosoma evansi, parasitos de humanos e animais, respectivamente. Modelos tridimensionais das proteínas XPC de T. cruzi e T. evansi foram feitos e observou-se poucas diferenças estruturais entre estas proteínas. Durante testes, a inserção do gene XPC de T. evansi (TevXPC) em T. cruzi resultou em crescimento celular mais lento em condições normais. Após o tratamento com cisplatina, T. cruzi superexpressando seu próprio gene XPC (TcXPC) foi capaz de recuperar as taxas de divisão celular mais rapidamente do que T. cruzi expressando o gene TevXPC. Com base nesses testes, sugere-se que TevXPC (sendo uma proteína exógena em T. cruzi) interfere negativamente nos processos celulares em que TcXPC (a proteína endógena) está envolvida. Isso provavelmente ocorreu pois TevXPC é capaz de interagir com algumas moléculas ou proteínas endógenas de T.cruzi, mas é incapaz de interagir com outras. Isso reforça a importância do correto funcionamento de XPC dentro da célula.

Abstract Nucleotide excision repair (NER) acts repairing damages in DNA, such as lesions caused by cisplatin. Xeroderma Pigmentosum complementation group C (XPC) protein is involved in recognition of global genome DNA damages during NER (GG-NER) and it has been studied in different organisms due to its importance in other cellular processes. In this work, we studied NER proteins in Trypanosoma cruzi and Trypanosoma evansi, parasites of humans and animals respectively. We performed three-dimensional models of XPC proteins from T. cruzi and T. evansi and observed few structural differences between these proteins. In our tests, insertion of XPC gene from T. evansi (TevXPC) in T. cruzi resulted in slower cell growth under normal conditions. After cisplatin treatment, T. cruzi overexpressing its own XPC gene (TcXPC) was able to recover cell division rates faster than T. cruzi expressing TevXPC gene. Based on these tests, it is suggested that TevXPC (being an exogenous protein in T. cruzi) interferes negatively in cellular processes where TcXPC (the endogenous protein) is involved. This probably occurred due interaction of TevXPC with some endogenous molecules or proteins from T.cruzi but incapacity of interaction with others. This reinforces the importance of correctly XPC functioning within the cell.

The popliteal artery is located deep inside the popliteal fossa, and is an important landmark in surgical procedures. Lesions of this vessel and its branches can be dangerous, blocking circulation to the lower limb and leading to gangrene or even vascular failure. The aim of this work was to describe the biometric characteristics of the bifurcations of the popliteal artery and the tibiofibular trunk in relation to the head of the fibula in 38 lower limbs through dissection. The bifurcation of the both arteries was present in all the cases. The mean confidence interval for the bifurcation of the popliteal artery was from 2.82 cm to 3.18 cm from the head of the fibula, and that of the bifurcation of the tibiofibular trunk was from 5.72 cm to 6.68 cm. The bifurcation of the popliteal artery into the anterior tibial artery and tibiofibular trunk showed a more constant positioning than the level of the birfurcation of the posterior tibial artery and fibular artery. These data can help in the development of new access routes to these arteries, or the optimization of surgical planning in the region in question.

La arteria poplítea se encuentra en la fosa del mismo nombre y es un punto de referencia importante en los procedimientos quirúrgicos. Las lesiones de este vaso y sus ramas pueden ser peligrosas, bloqueando la circulación a la extremidad inferior pudiendo llevar a gangrena o incluso a la insuficiencia vascular. El objetivo de este trabajo fue describir la anatomía de la arteria poplítea y el nivel de su primera bifurcación en tronco tibiofibular y arteria tibial anterior, y además el nivel de bifurcación del tronco en arterias tibial posterior y fibular (segunda bifurcación), en relación a la cabeza de la fíbula. Para ello se realizó disección en 38 miembros inferiores. El intervalo de confianza para la media de la primera bifurcación fue de 2,82 cm a 3,18 cm de la cabeza de la fíbula y la de la segunda bifurcación fue de 5,72 cm a 6,68 cm. La bifurcación de la arteria poplítea en la arteria tibial anterior y el tronco tibiofibular mostró un posicionamiento más constante que la altura de la bifurción de la arteria tibial posterior y la arteria fibular. Estos datos pueden ayudar en el desarrollo de nuevas vías de acceso a estas arterias, o la optimización de la planificación quirúrgica de la región.