No description available.

No description available.

No description available.

Yes / Peripheral nerve injuries affect a large proportion of the global population, often causing significant morbidity and loss of function. Current treatment strategies include the use of implantable nerve guide conduits (NGC's) to direct regenerating axons between the proximal and distal ends of the nerve gap. However, NGC's are limited in their effectiveness at promoting regeneration Current NGCs are not suitable as substrates for supporting either neuronal or Schwann cell growth, as they lack an architecture similar to that of the native extracellular matrix (ECM) of the nerve. The aim of this study was to create an acellular porcine peripheral nerve using a novel decellularisation protocol, in order to eliminate the immunogenic cellular components of the tissue, while preserving the three-dimensional histoarchitecture and ECM components. Porcine peripheral nerve (sciatic branches were decellularised using a low concentration (0.1%; w/v) sodium dodecyl sulphate in conjunction with hypotonic buffers and protease inhibitors, and then sterilised using 0.1% (v/v) peracetic acid. Quantitative and qualitative analysis revealed a ≥95% (w/w) reduction in DNA content as well as preservation of the nerve fascicles and connective tissue. Acellular nerves were shown to have retained key ECM components such as collagen, laminin and fibronectin. Slow strain rate to failure testing demonstrated the biomechanical properties of acellular nerves to be comparable to fresh controls. In conclusion, we report the production of a biocompatible, biomechanically functional acellular scaffold, which may have use in peripheral nerve repair. / Engineering and Physical Sciences Research Council. Grant Number: EPSRC EP/F500513/1

No description available.

No description available.

Neurofibromatosis Type II (NF2) is a neurological disorder arising from mutations in the rif2 gene. NF2 is characterized by formation of bilateral vestibular schwannomas. These tumors arise from Schwann cells, the myelin-forming glia in nerves. Schwannoma cells lose the characteristic bipolar, spindle morphology and assume a round fibroblast-like phenotype. Phenotypic de-differentiation of schwannomas has been attributed to increased levels of Cdc42/Rac-GTP and activation of downstream pathways. The n/2 gene encodes the tumor suppressor called merlin. It is targeted to the plasma membrane by direct binding to paxillin at paxillin-binding domain 1, encoded by exon 2 of the nj2 gene. At the plasma membrane, merlin associates with B1-integrin and erbB2/3 receptors and actin regulating proteins. We hypothesize that merlin modulates actin polymerization, and thus cell shape, by controlling the activity of actin filament regulating proteins. We developed an in vitro model ofNF2 using ad-ere ( ad-Cre) viral mediated deletion of nj2 exon 2 in primary mouse Schwann cells. Within 5 days of ad-Cre infection, merlin levels fall to 40% of normal levels in Schwann cells. Moreover, the expressed merlin protein has the expected lower molecular weight and does not target to the plasma membrane. Schwann cells expressing this mutant merlin lose their characteristic bipolar shape. We tested the activation levels of2 candidate Cdc42/Rac dependent-actin regulating proteins in these cells. Using immunofluorescence, we found that the activity of these proteins increased dramatically within 4 days of n/2 inactivation. This increase in activity was then confirmed with western blotting. We conclude that the function of these actin-filament regulating proteins could contribute to changes in morphology associated with schwannoma formation in NF2.

Introdução: A simpatectomia torácica é o único tratamento, definitivo e eficaz, para a hiperidrose primária. A ramicotomia é um procedimento cirúrgico tão eficaz, mais conservador e com menos efeitos adversos que a simpatectomia convencional, contudo foi abandonada pela alta taxa de recidiva, atribuída, até então, à secção incompleta dos ramos comunicantes, ao desenvolvimento de outras vias de condução para o estímulo central e à regeneração neural. A avaliação histológica dos ramos comunicantes simpáticos após a ramicotomia, pode ajudar a entender o processo de recidiva dos sintomas da hiperidrose e, dessa forma contribuir para o desenvolvimento de estratégias para evitá-la. MATERIAL E MÉTODOS: 28 suínos foram submetidos à ramicotomia por videotoracospia e divididos randomicamente em 5 grupos, sacrificados com 15, 45, 90, 135 e 180 dias de pós-operatório (DPO). Os segmentos operados foram removidos cirurgicamente e submetidos à avaliação macroscópica da regeneração assim como análise histológica dos ramos comunicantes brancos e cinzentos para quantificação da reação inflamatória, deposição de fibras de colágeno grossas e finas, fibras reticulares e células de Schwann por imuno-histoquímica. Os dados foram comparados ao grupo controle, composto por segmentos intactos, não operados. RESULTADOS: Não houve regeneração macroscópica no grupo de 15 DPO sendo presente em 41,6% dos casos no grupo 180 DPO (p < 0,05). A reação inflamatória foi determinante no processo de degeneração Walleriana, com presença importante das células de Schwann nos ramos pré-ganglionares (p < 0,05), as células de Schwann apresentaram evolução semelhante nos dois ramos a partir do grupo de 45DPO, mantendo-se em menor número nos ramos cinzentos. As fibras de colágeno foram cruciais na cicatrização e as fibras reticulares importantes na regeneração neural, com correlação negativa entre elas (r = - 0,414; p < 0,01). A deposição de fibras de colágeno foi maior nos ramos cinzentos, apresentando pico de deposição no grupo 135 DPO e declínio importante no grupo 180 DPO (p < 0,05). CONCLUSÕES: A ramicotomia permite a secção completa de todos os ramos comunicantes do gânglio simpático. A taxa de regeneração histológica deve ser maior que a taxa de recidiva dos sintomas no humano, devido a regenerações não funcionais. O processo regenerativo é similar nos ramos brancos e cinzentos, com tendências menores para os últimos. A regeneração dos ramos comunicantes deve ser um dos principais fatores de recidiva da hiperidrose após a ramicotomia / INTRODUCTION: Thoracic sympathectomy is the only definitive and efficient treatment for primary hyperhidrosis. The ramicotomy is a surgical procedure that is as efficient as conventional sympathectomy but more conservative, having less adverse effects then conventional sympathectomy. This procedure was abandoned on account of the high recurrence rate, attributed to the incomplete section of the rami communicantes and to the development of new pathways of conduction to the central stimuli. MATHERIAL AND METHODS: Twenty-eight swine underwent bilateral videothoracoscopic ramicotomy and were randomly divided into 5 groups. The animals were sacrificed at 15, 45, 90, 135 and 180 days post-operative POD. The segments were removed and evaluated for macroscopic regeneration and histological analysis of the white and gray rami communicantes analyzing the inflammatory reaction, deposition of thin and thick collagen fibers, reticular fibers and Schwann cells. The data was compared to intact segments of sympathetic trunk as a positive control. RESULTS: There was neither macroscopic nor microscopic regeneration at the 15 POD group. The remaining groups had an average of 41,6% of regeneration, more significant at the 180 POD group (p<0.05). The inflammatory reaction was crucial in the process of Wallerian degeneration, with an important participation of the Schwann cells in the pre-ganglionic rami (p<0.05). The Schwann cells presented a similar evolution in both rami beginning at the 45 POD group, with a smaller count in the gray rami. The collagen fibers were significant in the cicatrization and the reticular fibers were important in neural regeneration, with a meaningful negative correlation between them (r = - 0,414; p < 0,01). The rate of deposition of the collagen fibers was greater in the white rami when compared to the gray rami in the first trimester and less important in the second trimester (p<0.05). CONCLUSIONS: Ramicotomy allows complete section of all rami communicantes of the sympathetic ganglia. The histological regeneration might be greater than the recurrence rates of clinical symptoms as seen in the human being due to non-functional regenerations. The restoration process is similar in both white and gray rami, with smaller tendencies in the last one. The regeneration of the could be one of the main factors for recurrence of hyperhidrosis following ramicotomy

A Esclerose Lateral Amiotrófica (ELA) é uma doença neurodegenerativa progressiva e incurável, caracterizada pela perda seletiva dos neurônios motores (NM) superiores e inferiores com uma sobrevida média de 3 anos. As manifestações clínicas dependem da topografia e comprometimento dos NM. De causa desconhecida, descrições apontam para a participação das células gliais (astrócitos, microglia e célula de Schwann) na toxicidade neuronal. A retração precoce do axônio no músculo esquelético sugere a participação da célula de Schwann na morte neuronal retrógrada (dying back). Este estudo descreveu as alterações na expressão gênica no nervo motor extensor curto do hálux ainda funcionante dos pacientes ELA e o ramo motor do nervo acessório de sujeitos-controle (19 ELA, sendo 9 ELA espinhal e 5 ELA bulbar; 5 controles), utilizando-se plataformas expandidas de microarranjos de DNA (microarray) e análises de bioinformática (DAVID e os seus bancos de dados Kyoto Encyclopedia of Genes and Genomes e o Gene Onthology Consorciun Anottation). Os resultados foram validados por PCRq e Redes de Interação de Proteínas foram geradas pelo Cytoscape. Foram encontrados 138 genes diferencialmente expressos entre esses grupos. O ribossomo e a síntese proteica foram apontados como elementos centrais no estudo em eventos relacionados tanto à neurotoxicidade quanto a protetivos. As Redes destacaram o gene EPS8 na ELA (ambas as formas, ELA bulbar e espinhal) em relação aos controles e o gene FAU na ELA bulbar em relação à ELA espinhal. Os genes e as vias apontados neste estudo deverão ser testados como alvos terapêuticos em estudos futuros envolvendo a ELA / Amyotrophic lateral sclerosis (ALS) is an incurable progressive neurodegenerative disease characterized by the selective loss of upper and lower motor neurons (MN), with a median survival of 3 years. Clinical manifestations depend on onset site and involvement of the MN. Although the cause of ALS is unknown, reports point towards the participation of glial cells (astrocytes, microglia and Schwann cells) in the neuronal toxicity. The early retraction of the axonium indicates a participation of the Schwann cells in retrograde neuronal death (dying back). The current study described the abnormalities in the genic expression of the functioning extensor hallucis brevis motor neuron from ALS subjects, and the motor branch of the accessory nerve from control subjects (19 ALS, being 9 spinal and 5 bulbar types; 5 controls), through an expanded platform of DNA microarrays and bioinformatics analyses (DAVID, Kyoto Encyclopedia of Genes and Genomes, and Gene Onthology Consortium Annotation databases). The results were validated by Quantitative PCR (PCRq) and Protein-Protein interaction network generated by Cytoscape. A total of 138 differentially expressed genes were found in these groups. In this study, the ribosome and protein synthesis were pointed as central elements related both to neurotoxicity and protective events. These networks highlighted the EPS8 gene in ALS (in both types, bulbar and spinal) when correlated to controls, and the FAU gene in bulbar ALS in relation to spinal ALS. The genes and pathways identified in this study should be tested as therapeutic targets in future studies approaching ALS

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No. of bitstreams: 2 Tese - Giselle Bonifacio Neves Mendonça - 2013.pdf: 4442248 bytes, checksum: fd3c1ae469f5bfd89f5767680dc30981 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-12-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Peripheral nerves are constant targets of traumatic injuries such as crushing and partial or complete sections resulting in decrease or loss of motor function and sensitivity of the innervated area, its severity will depend on the involvement of nervous structures. The worst damage frame is that of total nerve collapse (neurotmesis), which invariably requires surgical treatment. This study aimed to evaluate the morphological and functional effects of rat’s sciatic nerve regeneration after surgical section tubing with silicone chamber and treatment with low-intensity laser (830 nm) in 126 days. We used two groups, control (GC) and laser (GL) with six animals in each. All animals underwent left sciatic nerve neurotmesis followed by tubing with silicone chamber with five mm distance between nerve stumps. Animals in GL received radiation with a wavelength of 830 nm, energy density of 4.13 J/cm², on eight points from the spinal cord to nerve injury site, totaling 40 days of irradiation divided into two distinct periods. The first stage began at the immediate post-operative period where 20 laser applications were performed on alternate days. The second stage occurred 40 days before performing euthanasia in animals submitted to more than 20 days of laser applications on alternate days. During the experiment, we performed functional assessment through the Sciatic Functional Index and Ankle Angle. After 126 days, the animals were euthanized and the fragments of the nerves were removed and fixed in 10% formalin buffered for histological analysis with HE, Luxol Fast Blue and Picrosirius Red staining, and immunohistochemistry with neurofilament antibody (NF), FGF-2 and S-100. Microscopically, we observed the presence of axonal growth, Wallerian degeneration, inflammatory infiltrate and fascicular reorganization. For HE analysis, we stablished descriptive scores and for the other histological data we carried out quantitative analysis through program Image J. In GL we observed better axonal growth, reorganization of issues, absence of inflammatory infiltrate, greater amount of myelin and less collagen, increased expression of S-100 and NF and lower expression of FGF-2. Regarding the function of the sciatic nerve, no functional improvement was observed. / Os nervos periféricos são alvos constantes de lesões de origem traumática, como esmagamento e secções parciais ou totais que resulta em diminuição ou perda da motricidade e da sensibilidade no território inervado, cuja severidade dependerá do acometimento de estruturas nervosas. O pior quadro de lesão é aquele em que ocorre ruptura total do nervo (neurotmese), o qual requer invariavelmente tratamento cirúrgico. Este estudo teve o objetivo de avaliar os efeitos morfológicos e funcionais da regeneração do nervo isquiático de rato após secção cirúrgica, tubulização com câmara de silicone e tratamento com laser de baixa intensidade (830 nm) em 126 dias. Utilizaram-se dois grupos, controle (GC) e laser (GL) com seis animais em cada. Todos os animais foram submetidos à neurotmese do nervo isquiático esquerdo, seguido de tubulização com câmara de silicone com cinco mm de distância entre os cotos nervosos. Os animais do GL receberam radiação com comprimento de onda de 830nm, densidade de energia de 4,13J/cm², em oito pontos, desde a região da medula espinhal até o local de lesão do nervo, totalizando 40 dias de irradiação divididos em dois momentos distintos. O primeiro momento iniciou-se no pós-cirúrgico imediato em que foram realizadas 20 aplicações de laser, em dias alternados. O segundo momento ocorreu 40 dias antes de realizar a eutanásia dos animais com mais 20 dias de aplicações de laser, em dias alternados. Durante o experimento procedeu-se avaliação funcional por meio do Índice Funcional do Ciático e Ângulo do Tarso. Após 126 dias os animais foram submetidos à eutanásia e os fragmentos dos nervos foram retirados e fixados em formol tamponado a 10% para análise histológica, com as colorações de HE, Luxol Fast Blue e Picrosirius Red, e imunoistoquímica com os anticorpos neurofilamento (NF), S100 e FGF-2. Microscopicamente, avaliou-se a presença de proliferação axonal, degeneração Walleriana, reorganização fascicular e infiltrado inflamatório. Para a análise do HE estabeleceram-se escores descritivos e para os demais dados histológicos procedeu-se análise quantitativa por meio do programa Image J. Observou-se no GL melhor proliferação axonal, reorganização dos fascículos, ausência de infiltrado inflamatório, maior quantidade de mielina e menor quantidade de colágeno, maior expressão de S-100 e NF e menor expressão de FGF-2. Com relação à função do nervo isquiático, não se observou melhora funcional.