Effects of intraoperative irradiation (IORT) and intraoperative hyperthermia (IOHT) on canine sciatic nerve: Histopathological and morphometric studies

Purpose/Objective: Peripheral neuropathies have emerged as the major dose-limiting complication reported after intraoperative radiation therapy (IORT). The combination of IORT with hyperthermia may further increase the risk of peripheral nerve injury. The objective of this study was to evaluate histopathological and histomorphometric changes in the sciatic nerve of dogs, after IORT with or without hyperthermia treatment. Methods and Materials: Young adult beagle dogs were randomized into five groups of 3-5 dogs each to receive IORT doses of 16, 20, 24, 28, or 32 Gy, Six groups of 4-5 dogs each received IORT doses of 12, 16, 20, 24, or 28 Gy simultaneously with 44 degrees C of intraoperative hyperthermia (IOHT) for 60 min. One group of dogs acted as hyperthermia-alone controls. Two years after the treatment, dogs were euthanized, and histopathological and morphometric analyses were performed. Results: Qualitative histological analysis showed prominant changes such as focal necrosis, mineralization, fibrosis, and severe fiber loss in dogs which received combined treatment. Histomorphometric results showed a significantly higher decrease in axon and myelin and small blood vessels, with a corresponding increase in connective tissue in dogs receiving IORT plus hyperthermia treatment, The effective dose for 50% of nerve fiber loss (ED50) in dogs exposed to IORT only was 25.3 Gy, The ED50 for nerve fiber loss in dogs exposed to IORT combined with IOHT was 14.8 Gy, The thermal enhancement ratio (TER) was 1.7. Conclusion: The probability of developing peripheral neuropathies in a large animal model is higher when IORT is combined with IOHT, when compared to IORT application alone. To minimize the risk of peripheral neuropathy, clinical treatment protocols for the combination of IORT and hyperthermia should not assume a thermal enhancement ratio (TER) to be lower than 1.5, (C) 1999 Elsevier Science Inc

ULTRASTRUCTURAL MORPHOMETRIC ANALYSIS OF PERIPHERAL-NERVES AFTER INTRAOPERATIVE IRRADIATION

Intraoperative irradiation (IORT) is used to enhance local tumour control by using large, single doses while removing critical structures from the treatment field. Peripheral nerve remains a dose-limiting normal tissue that often cannot be removed from the field. To assess ultrastructural changes in canine sciatic nerve after IORT, computerized morphometric analysis of plastic sections and electron micrographs of nerve cross-sections was used. Surgically exposed sciatic nerves were irradiated with 6 MeV electrons to 12, 20 or 28 Gy. Twelve months after treatment dogs were killed humanely and the nerves from three dogs per dose group, including non-irradiated controls, were analyzed. Twelve months after 28-Gy IORT a significant decrease in nerve fiber density occurred. Nerve fiber loss was particularly prominent in the central portion of the nerve predominantly among large nerve fibers. Other nerve fiber parameters including fiber and axon area, diameter and perimeter, myelin thickness, form factor (measure of roundness), and G ratio (axon diameter/fiber diameter) did not show significant, dose-related changes. An increase in microtubule and neurofilament density in irradiated nerve axons was found. These changes are suggestive of radiation-induced hypoxia (damage to microvasculature) resulting in axon damage and subsequent nerve fiber loss as a possible mechanism of late radiation injury to peripheral nerve

Effects of intraoperative irradiation (IORT) and intraoperative hyperthermia (IOHT) on canine sciatic nerve:Histopathological and morphometric studies

Purpose/Objective: Peripheral neuropathies have emerged as the major dose-limiting complication reported after intraoperative radiation therapy (IORT). The combination of IORT with hyperthermia may further increase the risk of peripheral nerve injury. The objective of this study was to evaluate histopathological and histomorphometric changes in the sciatic nerve of dogs, after IORT with or without hyperthermia treatment. Methods and Materials: Young adult beagle dogs were randomized into five groups of 3-5 dogs each to receive IORT doses of 16, 20, 24, 28, or 32 Gy, Six groups of 4-5 dogs each received IORT doses of 12, 16, 20, 24, or 28 Gy simultaneously with 44 degrees C of intraoperative hyperthermia (IOHT) for 60 min. One group of dogs acted as hyperthermia-alone controls. Two years after the treatment, dogs were euthanized, and histopathological and morphometric analyses were performed. Results: Qualitative histological analysis showed prominant changes such as focal necrosis, mineralization, fibrosis, and severe fiber loss in dogs which received combined treatment. Histomorphometric results showed a significantly higher decrease in axon and myelin and small blood vessels, with a corresponding increase in connective tissue in dogs receiving IORT plus hyperthermia treatment, The effective dose for 50% of nerve fiber loss (ED50) in dogs exposed to IORT only was 25.3 Gy, The ED50 for nerve fiber loss in dogs exposed to IORT combined with IOHT was 14.8 Gy, The thermal enhancement ratio (TER) was 1.7. Conclusion: The probability of developing peripheral neuropathies in a large animal model is higher when IORT is combined with IOHT, when compared to IORT application alone. To minimize the risk of peripheral neuropathy, clinical treatment protocols for the combination of IORT and hyperthermia should not assume a thermal enhancement ratio (TER) to be lower than 1.5, (C) 1999 Elsevier Science Inc

Calçado para pessoas com diabetes como forma de prevenção ao pé diabético

Este Trabalho de Conclusão de Curso (TCC) tenciona o desenvolvimento de um calçado para pessoas com diabetes, com foco no público feminino, como forma de prevenção aos pés diabéticos. O trabalho é divido em duas etapas, a primeira aborda o planejamento de projeto, a fundamentação teórica, o projeto informacional e o projeto conceitual, fundamentando o processo de desenvolvimento do produto para a realização da segunda etapa, que se conclui com a geração de um protótipo do produto proposto, um calçado que contribua para o não aparecimento de lesões nos pés. A segunda etapa abrange a criação do produto e suas etapas de desenvolvimento (criação de ideias, seleção e detalhamento da melhor alternativa). Inicialmente foi exposto o contexto no qual o produto será desenvolvido, definiu-se o público-alvo ao qual será destinado e fez-se um panorama dos conhecimentos necessários para o andamento do projeto, que culminou na elaboração de um conceito do produto, utilizado como foco na geração de alternativas. Posteriormente a ideia mais adequada foi selecionada, respeitando os requisitos elencados. A alternativa final combina tecnologias utilizadas em calçados de conforto e calçados de prevenção a lesões como o uso de palmilha que absorva impacto, forro com poucas costuras e capaz de absorver suor, flexibilidade do cabedal e forma maior, condizentes com as necessidades do público-alvo. O projeto foi validado através do prótipo avaliado pelo público-alvo, tanto em seu aspecto (estética) quanto no conforto propiciado.This Course Completion Work (TCC) intends to develop footwear for people with diabetes, focusing on the female audience, as a way to prevent diabetic foot. The work is divided in two stages. The first one deals with the project planning, the theoretical basis, the informational project and the conceptual project, basing the product development process for the second stage, which concludes with the generation of a prototype of the proposed product, a footwear that contributes to the non-appearance of foot injuries. The second stage covers the creation of the product and its stages of development (creation of ideas, selection and detailing of the best alternative). Initially, the context in which the product will be developed was defined, the target audience was defined and an overview of the necessary knowledge for the progress of the project, culminating in the elaboration of a concept of the product, used as focus on generating alternatives. Subsequently, the most appropriate idea was selected, respecting the requirements that were listed. The ultimate alternative combines technologies used in comfort footwear and injury-prevention footwear such as the use of impact-absorbing insole, a lining with few seams, and able to absorb sweat, flexibility of the material of the shoe and a bigger shape, consistent with the needs of the target audience. The project was validated through the prototype evaluated by the target public, based in their appearance (aesthetic) and in the comfort provided