• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 54
  • 36
  • 9
  • 5
  • 5
  • 4
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 136
  • 33
  • 31
  • 28
  • 24
  • 20
  • 19
  • 16
  • 15
  • 15
  • 14
  • 12
  • 11
  • 11
  • 11
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Implication de la chaîne α1 de laminine dans l’angiogenèse physiologique et tumorale / Involvement of laminin alpha 1 chain in physiological and tumor angiogenesis

Bach, Elmina 26 September 2012 (has links)
Les laminines, composants majeurs des lames basales, sont des hétérodimères glycosylés formés de trois chaînes α, β et γ. La chaîne α1 de laminine (LMα1), caractéristique du trimère LM111 est indispensable au développement de la membrane limitante interne de la rétine, sa perte de fonction et mutation impactant négativement l’angiogenèse physiologique, tandis que sa surexpression stimule l’incidence de la tumorigenèse colique, la maturation des vaisseaux sanguins et l’expansion des fibroblastes. La LMα1 favorise la prolifération des cellules cancéreuses coliques et stimule l’expression du VEGFA, des composants de la voie Notch, de Dll4 et de ses cibles Hey1 et Hey2 dans le stroma tumoral. Inversement, la perte de fonction et la mutation de la LMα1 diminuent l’expression de Dll4, Hey1 et Hey2 dans la rétine. L’action de la LMα1 sur l’expression de ces facteurs proangiogéniques est sélective, car en étant une molécule chémoattractante pour les fibroblastes associés au cancer elle y stimule l’expression de VEGFA et de Dll4. Tandis que dans les cellules endothéliales, son action stimulatrice sur Dll4 s’accompagne de l’activation de la voie Notch. Chez l’homme, dans le contexte de tumorigenèse colique, la LMα1 est fortement exprimée. Cette surexpression s’accompagne d’une augmentation de l’expression du VEGFA et de Dll4. A la lumière de ces résultats, LMα1 pourrait constituer une cible potentielle dans les thérapies anti-anticancéreuses. / Laminins, major components of basement membrane are glycosylated heterodimers composed of three chains α, β and γ. Laminin α1 chain (LMα1), specific to LM111 trimer is essential in development of retinal inner limiting membrane. Loss of function and mutation of LMα1 negatively impact physiological angiogenesis, whereas its overexpression promotes colon cancer incidence, tumor cell proliferation, blood vessel maturation and fibroblast expansion. LMα1 stimulates VEGFA, Notch pathway components Dll4 and its targets Hey1 and Hey2 in tumor stroma. Contrarily, mutation and loss of function of LMα1 decrease Dll4, Hey1 and Hey2 expression in retina. LMα1 differentially regulates the expression of pro-angiogenic factors. As a chemoattractive molecule for cancer associated fibroblasts, LMα1 stimulates VEGFA and Dll4 expression in these stromal cells, while in endothelial cells, LMα1 stimulated Dll4 triggers Notch pathway activation. LMα1 is overexpressed in human cancer, which associated with increased expression of VEGFA and Dll4. In settings of these data, LMα1 could be a potential target in anticancer therapies.
122

Peptídeo AG73, derivado da laminina-111, induz migração, invasão e secreção de proteases em linhagem celular derivada de carcinoma epidermóide oral através de sindecana-1 e integrina b1 / Laminin-111-derived peptide AG73 regulates migration, invasion and protease activity of cell line derived from oral squamous cell carcinoma through syndecan-1 and b1 integrin.

Adriane Sousa de Siqueira 24 September 2009 (has links)
Carcinona epidermóide é um prevalente tumor de cabeça e pescoço relacionado a altas taxas de mortalidade. Neste trabalho, verificamos se AG73 (RKRLQVQLSIRT, cadeia a1), peptídeo derivado da laminina-111, regula migração, invasão e secreção de protease em células de carcinoma epidermóide oral (OSCC). Cadeia a1 da laminina e MMP9 estão expressas neste tumor in vivo e in vitro. AG73 induziu aumento da taxa migratória de células OSCC em ensaios de ferida e migração, e também estimulou invasão em ensaio em câmaras bipartites com Matrigel. Células OSCC crescidas sobre AG73 exibiram aumento dose-dependente de MMP9, detectado por zimografia. Buscamos receptores de AG73 que regulariam atividade nesta linhagem. Células OSCC crescidas sobre AG73 exibiram colocalização de sindecana-1 e integrina b1, e silenciamento desses receptores com RNA de interferência promoveu diminuição de migração e invasão dependente de AG73 nestas células. Esses resultados sugerem que sindecana-1 e integrina b1, ativados por AG73, podem regular migração, invasão e secreção de MMPs em células OSCC. / Oral squamous cell carcinoma is a prevalent head and neck tumor, related to high mortality rates. Here we studied the role played by AG73 (RKRLQVQLSIRT, a1 chain) on migration, invasion and protease secretion of a cell line (OSCC) from human oral squamous cell carcinoma. Laminin a1 chain and MMP9 are expressed in oral squamous cell carcinoma cells in vivo and in vitro. AG73 increased migratory activity of OSCC cells, as shown by monolayer wound assays and migration assays. This peptide also stimulated cell invasion in chemotaxis chambers coated with Matrigel. OSCC cells cultured on AG73 showed a dose-dependent increase of MMP9 secretion, detected by zymography. We searched for AG73 receptors regulating activities in this cell line. OSCC cells grown on AG73 exhibited colocalization of syndecan-1 and b1 integrin, and siRNA knockdown of these receptors decreased AG73-dependent migration and invasion of OSCC cells. Our results suggest that syndecan-1 and b1 integrin signaling downstream of AG73 regulate migration, invasion and MMP secretion by OSCC cells
123

Adesão e atividade de protease são reguladas pelo peptídeo derivado da laminina AG73, sindecan-1 e integrina 1 em linhagem celular derivada de carcinoma adenóide cístico / Ahesion and protease activity are regulated by the laminin-derived peptide AG73, syndecan-1 and bintegrin in cell line derived from adenoid cystic carcinoma.

Elaine Cyreno Oliveira 01 October 2009 (has links)
Estudamos indução da atividade de MMP pelo peptídeo da laminina a1 AG73 em linhagem celular (CAC2) de carcinoma adenóide cístico. CAC2 cultivadas em laminina-111 com AG73 geraram espaços pseudocísticos. Inibidor de MMP diminuiu tais espaços, sugerindo ação de MMPs. CAC2 crescidas sobre AG73 mostraram aumento dose-dependente de MMP9. RNAi para MMP9 diminuiu remodelação em cultura 3D. Buscamos receptores de AG73 ligados à atividade de MMP9. CAC2 crescidas sobre AG73 exibiram colocalização de sindecan-1 e integrina b1. RNAi para sindecan-1 ou para integrina b1 geraram, isolados, redução na adesão a AG73 e nas atividades de remodelação e de protease. Duplo RNAi estudou a cooperação entre os receptores e promoveu diminuição na adesão a AG73 e na atividade de MMP. Distinção de receptores foi feita por cromatografia de afinidade e espectrometria de massa, através de colunas de afinidade com AG73 acoplado, que resultou em possíveis receptores, como integrinas b1 e aV. Sugerimos que AG73 regula adesão e secreção de MMP em células CAC2 através de sindecan-1 e integrina b1. / We studied induction of MMP activity by b1-laminin peptide AG73 in adenoid cystic carcinoma cell line (CAC2). Cells grown inside AG73-enriched laminin-111 exhibited pseudocystics spaces. MMP inhibitor decreased those spaces, suggesting MMPs action. Cells grown on AG73 showed a dose-dependent increase of MMP9 secretion. MMP9 siRNAi decreased remodeling in 3D culture. We searched for AG73 receptors regulating MMP9 activity. CAC2 grown on AG73 exhibited colocalization of syndecan-1 and b1 integrin. Syndecan-1 siRNA or siRNA b1 integrin showed reduction in adhesion to AG73 and in remodeling and protease activities. Double-knockdown explored syndecan-1 and 1 integrin cooperation and showed decrease in adhesion to AG73 and in MMP activity. Receptors characterization was made by affinity chromatography followed by mass spectrometry through AG73-affinity columns and showed putative receptors, like b1 and aV integrins. We suggest that AG73 peptide regulates adhesion and MMP secretion in CAC2 cells through syndecan-1 and b1 integrin.
124

Imunoproteção de ilhotas pancreáticas microencapsuladas em biomateriais inovadores e seu potencial terapêutico no diabetes mellitus tipo 1 / Immunoprotection of pancreatic islets microencapsulated in inovative biomaterials and its therapeutic potential in type 1 Diabetes Mellitus

Ana Lúcia Campanha Rodrigues 08 May 2012 (has links)
O transplante de ilhotas microencapsuladas constitui uma alternativa terapêutica interessante para o Diabetes Mellitus tipo 1, permitindo um melhor controle glicêmico e eliminando a necessidade de imunossupressão. Entretanto, a manutenção a longo prazo da viabilidade das células-&#946; ainda é um desafio. No isolamento, a perda da matriz extracelular e as condições hipóxicas subsequentes afetam decisivamente a sobrevivência e funcionalidade das ilhotas. Objetivo Para diminuir o estresse sobre o enxerto, levando a um sucesso prolongado do transplante, propôs-se a adição de perfluorocarbono (PFC) ou laminina (LN), moléculas associadas respectivamente à oxigenação e interações célula-célula, ao biomaterial baseado em alginato, Biodritina, adequado ao encapsulamento celular. Metodologia Para testar a estabilidade das formulações PFC-Biodritina e LN-Biodritina, microcápsulas foram submetidas a diferentes estresses (rotacional, osmótico, temperatura e cultura) por 7 e 30 dias. A pureza do biomaterial foi avaliada pela coincubação com macrófagos murinos RAW264.7, por 3, 9 e 24h, quando a ativação dos macrófagos foi observada pela expressão gênica de IL- 1&#946; e TNF&#945;. Microcápsulas implantadas i.p. em camundongos foram recuperadas após 7 ou 30 dias, para análises de biocompatibilidade. A expressão de níveis de mRNA (bax, bad, bcl-2, bcl-XL, xiap, caspase 3, mcp1/ccl2, hsp70, ldh, insulina 1 e 2), proteínas (Bax, Bcl-XL e Xiap) e a atividade de Caspase3 foram avaliadas em ilhotas microencapsuladas com PFC- e LN-Biodritina, após cultura de 48h em condições de normóxia e hipóxia (<2% O2). Camundongos diabéticos foram transplantados com ilhotas encapsuladas nas diferentes formulações e os animais foram monitorados pelas variações de massa corporal, glicêmicas e pela funcionalidade do enxerto (TOTGs). As ilhotas foram recuperadas de animais normo ou hiperglicêmicos e uma análise de biocompatibilidade das cápsulas foi realizada, assim como a avaliação funcional das células-&#946;. Após o explante, a glicemia dos animais normoglicêmicos foi monitorada para se atestar a eficiência das ilhotas transplantadas. Resultados Microcápsulas de PFC- e LN-Biodritina são tão estáveis e biocompatíveis quanto as de Biodritina. Para ilhotas encapsuladas em ambos os materiais, em normóxia ou hipóxia, observou-se uma modulação gênica que sugere proteção contra apoptose. Adicionalmente, encontrou-se uma diminuição na expressão de genes indicadores de estresse (mcp1, hsp70). Uma diminuição nos níveis de mRNA de ldh foi vista para PFC-Biodritina, mas o oposto foi encontrado para LN-Biodritina. As diferenças encontradas na expressão proteica sugerem o mesmo padrão anti-apoptótico. Caspase3 não foi modulada por nenhum biomaterial. Nos experimentos de transplante, apenas LN-Biodritina levou reversão prolongada do diabetes, com 60% dos animais normoglicêmicos, 198 dias pós-cirurgia, comparado a 9% do grupo Biodritina. O TOTG demonstrou que camundongos transplantados com ilhotas encapsuladas secretaram mais insulina do que controles, 60 (LN-Biodritina) ou 100 (PFC- e LN-Biodritina) dias pós-cirurgia. O explante restabeleceu a hiperglicemia nos camundongos. Microcápsulas recuperadas de animais hiperglicêmicos apresentavam uma extensa adesão celular. Testes de secreção de insulina in vitro demonstraram que somente ilhotas do grupo normoglicêmico responderam às variações da concentração de glicose. Conclusão A adição de moléculas bioativas à Biodritina é capaz de diminuir o estresse em ilhotas isoladas e tem o potencial de melhorar a terapia pelo transplante de ilhotas. / Transplantation of microencapsulated islets represents an attractive therapeutical approach to treat type 1 Diabetes Mellitus, accounting for an improved glycemic control and the abolishment of immunosuppressive therapies. However, maintenance of long-term &#946;-cell viability remains a major problem. During islet isolation, the loss of extracellular matrix interactions and the hypoxic conditions thereafter dramatically affect &#946;-cell survival and function. Objective To lessen the burden of islet stress and achieve a better outcome in islet transplantation we tested the addition of perfluorocarbon (PFC) or laminin (LN), molecules associated respectively with oxygenation and cell-cell interaction, to Biodritin, an alginate-based material suitable for cell microencapsulation. Methodology To test the stability of PFC-Biodritin and LN-Biodritin composites, microcapsules were subjected to different stresses (rotational, osmotic, temperature and culture) for 7 and 30 days. To assess biomaterial purity microcapsules were co-incubated with RAW264.7 murine macrophage cell line for 3, 9 and 24h and macrophage activation was detected through mRNA levels of IL-1&#946; and TNF&#945;. Microcapsules were implanted i.p. in mice and retrieved after 7 or 30 days, for biocompatibility analyses. Gene expression at mRNA (bax, bad, bcl-2, bcl-XL, xiap, caspase 3, mcp1/ccl2, hsp70, ldh, insulin 1 and 2) and protein (Bax, Bcl-XL and Xiap) levels, together with Caspase3 activity, were evaluated in islets microencapsulated in PFC- or LN-Biodritin, upon culturing for 48h in normoxic or hypoxic (<2% O2) conditions. Diabetic mice were transplanted with PFC- or LN-Biodritin microencapsulated islets, followed by assessments of body weight, glycemia and graft function by oral glucose tolerance tests (OGTTs). Microencapsulated islets were retrieved from normoglycemic or hyperglycemic mice and biocompatibility analyses of the beads together with a functional assessment of the graft followed. After graft removal, normoglycemic animals had their glycemias monitored to attest the efficacy of the transplanted islets. Results PFC- and LN-Biodritin microcapsules were as stable and biocompatible as Biodritin. For both biomaterials in normoxia and hypoxia a modulation in gene expression was observed in islets associated with a protection against apoptosis. Also, a decreased expression of stress-related genes (mcp1, hsp70) was evidenced. ldh mRNA levels were down-regulated in PFC-Biodritin microencapsulated islets but upregulated in the presence of LN. Increased levels of insulin mRNA were observed. The differences seen in protein expression indicated the same anti-apoptotic pattern. Caspase3 activity was not different between groups. Concerning diabetes reversal experiments, only mice transplanted with LN-Biodritin microencapsulated islets presented a better outcome, with 60% remaining euglycemic at 198 days post-surgery, compared with 9% for the Biodritin group. OGTT showed that mice transplanted with encapsulated islets secreted more insulin than normal mice, 60 (LN-Biodritin) or 100 days (PFC- and LN-Biodritina) posttransplant. Hyperglycemia was achieved after the retrieval of microcapsules showing graft efficacy. Retrieved microcapsules revealed an extensive overgrowth in most beads from hyperglycemic mice. A static glucose stimulated insulin secretion test revealed that only islets from normoglycemic subjects were able to secrete insulin according to glucose concentration. Conclusion- The addition of bioactive molecules to Biodritin may lessen the stress of isolated islets and have the potential to improve islet transplantation therapy.
125

Immunhistokemisk undersökning av slemhinnepemfigoid och orala lichenoida reaktioner med epitelsläpp - En pilotstudie

Odobasic, Dennis, Mysliwiec, Marcel January 2020 (has links)
Syfte: Är att ta reda på om man med hjälp av immunhistokemi (IHC) med infärgning avantikroppar mot laminin-5 och C3d kan särskilja mellan slemhinnepemfigoid (MMP) ochorala lichenoida reaktioner (OLR) med epitelsläpp. Vidare undersöks graden inflammation för MMP och OLR för att fastställa om det går att se ett samband mellan grad av inflammation och antikroppsinfärgning.Material och metod: En pilotstudie utfördes på 10 prover med diagnosen MMP respektive 9 prover med OLR, som hämtades från Malmö universitets biobank. Proverna genomgickrutinfärgning respektive antikroppsinfärgning mot laminin-5 och C3d. Granskning av prover skedde i digitalmikroskop. Efteråt delades proverna in i grupper efter var infärgningen sågs. Sammanställning gjordes i Excel med stapeldiagram.Resultat: Ingen tendens till särskiljning ses mellan MMP och OLR avseende infärgning mot laminin-5 och C3d. Positiva utslag för infärgning mot Laminin-5 ses enhetligt på enbart en sida om epitelsläppet hos både snitten för MMP och OLR. Vidare kan det inte ses att snitt med diagnosen OLR har slumpartad infärgning mot laminin-5 på båda sidor om släppet. Det finns en tendens till att MMP-snitt får mer positiva utslag för infärgning mot C3d än för OLR snitt. Graden inflammation var högre i OLR snitt än för MMP snitt.Slutsats: Enligt studien går det inte att, med IHC, med infärgning av antikroppar mot laminin5 och C3d, kunna särskilja MMP och OLR med epitelsläpp. Större urval krävs för definitiva slutsatser. Vidare studier behövs för att utreda om det går att använda IHC för att särskilja MMP och OLR.Nyckelord: C3d, immunhistokemi (IHC), laminin-5, orala lichenoida reaktioner (OLR),slemhinnepemfigoid (MMP) / Aim: To investigate if it is possible to differentiate between the diagnoses mucous membrane pemphigoid (MMP) and oral lichenoid reactions (OLR) with epithelial detachment using immunohistochemistry (IHC) with antibodies against laminin-5 and C3d. Furthermore, the extent of inflammation was examined for MMP and OLR to determine if a correlation between the inflammation and immunostaining is evident.Material and method: A pilot study is conducted using 10 samples diagnosed with MMP and 9 samples diagnosed with OLR, collected from Malmö University’s biobank. H&E staining and immunostaining against laminin-5 and C3d is performed on the samples. Analysis is conducted using a microscope. Samples are then divided into groups depending on the staining. Excel is used to compile the results.Result: No differentiating tendencies are observed between MMP and OLR regardingimmunostaining against laminin-5 and C3d. Immunostaining against laminin-5 is positive for MMP and OLR and is seen continuously on only one side of the epithelial detachment.Furthermore, staining with laminin-5 is not seen as random staining on both sides of theepithelial detachment. Samples with MMP have a higher tendency to stain against C3dcompared to OLR samples. Inflammation is higher in OLR samples than those for MMP.Conclusion: According to this study it is not possible to differentiate between the diagnoses MMP and OLR with epithelial detachment using immunostaining against laminin-5 and C3d. A larger sample size is needed for a definitive conclusion. Additionally, further studies are required to conclude if IHC can be used to differentiate between MMP and OLR.Keywords: C3d, immunohistochemistry (IHC), laminin-5, mucous membrane pemphigoid(MMP), oral lichenoid reactions (OLR)
126

Genomanalyse beim landwirtschaftlichen Nutztier / Genome analysis in livestock

Beck, Julia 22 January 2008 (has links)
No description available.
127

Caracterização do perfil funcional de função motora e qualidade de vida de pacientes com diferentes subtipos de distrofia muscular congênita / Motor function profile characterization and quality of life in patients with different subtypes of congenital muscle dystrophy

Pontarolli, Marilia Nascimento 13 July 2015 (has links)
A Distrofia Muscular Congênita (DMC) se caracteriza clinicamente por hipotonia e fraqueza muscular, retardo do desenvolvimento motor e retrações fibrotendíneas. Instrumentos de avaliação clínica, como as escalas funcionais, motoras e de qualidade de vida, têm como objetivo quantificar o impacto da doença sobre as atividades diárias da vida do paciente, além de auxiliarem na caracterização de grupos de estudo heterogêneos. Sendo a DMC altamente heterogênea, traçar o perfil funcional dos pacientes com diferentes subtipos seria útil para caracterizar padrões funcionais e auxiliar no tratamento em equipe multidisciplinar. Objetivos: Caracterizar o perfil de funcionalidade e qualidade de vida de pacientes com DMC de diferentes subtipos e correlacioná-lo com a força muscular e grau de amplitude de movimento. Metodologia: Em uma amostra de 18 pacientes com DMC com idade de 12 + 3,2 anos e 13 pacientes com outras miopatias congênitas com idade de 13 + 2,6 anos foram aplicados em três visitas (V1, V2 e V3) os questionários SF-36 e Índice de Barthel (IB), além de realizada avaliação físico-motora (goniometria, força muscular) seguido de correlação com a escala funcional MFM-32 (Medida de Função Motora). Resultados: Houve significativa queda na qualidade de vida em pacientes Merosina (-) e em outras formas de DMC. O índice de Barthel (IB) apontou \"grave dependência\" final em pacientes merosina (-) e \"moderada dependência\" em outras formas de DMC. A goniometria mostrou diminuição da movimentação global em todos os grupos articulares avaliados em pacientes com merosina (-). Em outras formas de DMC, houve exceção de diminuição apenas em articulação distal de membros superiores. A força de todos os grupos musculares é significativamente afetada em ambos os grupos. Pacientes merosina (-) mostram diminuição significativa de funcionalidade nas três dimensões da escala MFM-32 (D1, D2 e D3), e em outras formas de DMC, apenas diminuição em D2 e D3. Houve moderada correlação positiva entre força muscular e D1 da escala MFM-32, forte correlação positiva entre goniometria e D2 e D3 em pacientes com merosina (-), não havendo correlação entre nenhuma variável e MFM-32 em outras formas de DMC. Conclusão: Pacientes com DMC apresentaram perfil funcional \"gravemente dependente\", com diminuição da qualidade de vida, observada em cinco de oito quesitos do questionário SF-36. A força muscular e a amplitude de movimento articular foram afetadas de forma generalizada em ambos os grupos de pacientes. Pacientes com merosina (-) mostraram-se mais afetados funcionalmente em posturas eretas e transferências, sendo correlacionada positivamente com a força muscular dos grupos dessa tarefa / Congenital Muscular Dystrophy (CMD) is characterized by hypotonia and weakness, motor development delay and muscular contractures. Instruments of clinical assessment, such as functional motor and quality of life scales are essential to quantify the impact of the disease on daily activities of the patient\'s life in addition to helping in the characterization of heterogeneous study groups. As the DMC highly heterogeneous, trace the functional profile of patients with different subtypes would be useful to characterize functional patterns and aid in the treatment by a multidisciplinary team. Objectives: To characterize the functionality and quality of life of children with different subtypes of DMC and to correlate them with the degree of muscle strength and range of motion. Methods: In a sample of 18 patients with CMD (aged 12 + 3.2 years) and 13 patients with other congenital myopathies (aged 13 ± 2.6 years) were applied in three visits (V1, V2 and V3) the SF-36 and Barthel Index (BI), and performed physical-motor assessment (goniometry, muscle strength) followed by correlation with functional scale MFM-32 (motor Function Measure. ). Results: There was a significant decrease in the quality of life in patients Merosin (-) and other forms of CMD. IB indicated \"severe dependence\" final in Merosin patients (-) and \"moderate dependence\" in other forms of CMD. Goniometry showed a decrease of the overall joint movement in all groups evaluated in patients with merosin (-).In other forms of DMC was decreased joint movement in all joint groups, except for the distal joint of the upper limbs. The strength of each muscle group was significantly affected in both groups. Patients merosin (-) show a significant decrease in the functionality on the 3 dimensions of MFM-32 scale (D1, D2, D3) in patients with other forms of DMC only reduction in D2 and D3. There was a moderate positive correlation between muscle strength and D1 of the SF-32 scale, strong positive correlation between goniometry and D2 and D3 in patients with Merosin (-), there was no correlation between this variable and MFM-32 in other forms of CMD. Conclusion: Patients with CMD showed functional profile \"severely dependent\" to low quality of life observed in five of eight areas of the SF-36 questionnaire. Muscle strength and range of motion were affected in a generalized manner in both patient groups. Patients with Merosin (-) are even more affected functionally in standing and transfers being positively correlated with muscle strength of the groups of this task postures
128

Chronic inflammation surrounding intra-cortical electrodes is correlated with a local, neurodegenerative state

McConnell, George Charles 18 November 2008 (has links)
Thanks to pioneering scientists and clinicians, prosthetic devices that are controlled by intra-cortical electrodes recording one's 'thoughts' are a reality today, and no longer merely in the realm of science fiction. However, widespread clinical use of implanted electrodes is hampered by a lack of reliability in chronic recordings, independent of the type of electrodes used. The dominant hypothesis has been that astroglial scar electrically impedes the electrodes. However, recent studies suggest that the impedance changes associated with the astroglial scar are not high enough to interfere significantly impair neural recordings. Furthermore, there is a time delay between when scar electrically stabilizes and when neural recordings fail (typically >1 month lag), suggesting that scar, per se, does not cause chronic recording unreliability. In this study, an alternative hypothesis was tested in a rat model, namely, that chronic inflammation surrounding microelectrodes causes a local neurodegenerative state. Chronic inflammation was varied in three ways: 1) stab wound control, 2) age-matched control, and 3) inter-shank spacing of a multishank electrode. The results of this study suggest that chronic inflammation, as indicated by activated microglia and reactive astrocytes, is correlated with local neurodegeneration, marked by neuron cell death and dendritic loss. Surprisingly, axonal pathology in the form of hyperphosphorylation of the protein Tau (the hallmark of many tauopathies, including Alzheimer's Disease) was also observed in the immediate vicinity of microelectrodes implanted for 16 weeks. Additionally, work is presented on a fast, non-invasive method to monitor the astrocytic response to intra-cortical electrodes using electrical impedance spectroscopy. This work provides a non-invasive monitoring tool for inflammation, albeit an indirect one, and fills a gap which has slowed the development of strategies to control the inflammatory tissue response surrounding microelectrodes and thereby improve the reliability of chronic neural recordings. The results of these experiments have significance for the field of neuroengineering, because a more accurate understanding of why recordings fail is integral to engineering reliable solutions for integrating brain tissue with microelectrode arrays.
129

Caracterização do perfil funcional de função motora e qualidade de vida de pacientes com diferentes subtipos de distrofia muscular congênita / Motor function profile characterization and quality of life in patients with different subtypes of congenital muscle dystrophy

Marilia Nascimento Pontarolli 13 July 2015 (has links)
A Distrofia Muscular Congênita (DMC) se caracteriza clinicamente por hipotonia e fraqueza muscular, retardo do desenvolvimento motor e retrações fibrotendíneas. Instrumentos de avaliação clínica, como as escalas funcionais, motoras e de qualidade de vida, têm como objetivo quantificar o impacto da doença sobre as atividades diárias da vida do paciente, além de auxiliarem na caracterização de grupos de estudo heterogêneos. Sendo a DMC altamente heterogênea, traçar o perfil funcional dos pacientes com diferentes subtipos seria útil para caracterizar padrões funcionais e auxiliar no tratamento em equipe multidisciplinar. Objetivos: Caracterizar o perfil de funcionalidade e qualidade de vida de pacientes com DMC de diferentes subtipos e correlacioná-lo com a força muscular e grau de amplitude de movimento. Metodologia: Em uma amostra de 18 pacientes com DMC com idade de 12 + 3,2 anos e 13 pacientes com outras miopatias congênitas com idade de 13 + 2,6 anos foram aplicados em três visitas (V1, V2 e V3) os questionários SF-36 e Índice de Barthel (IB), além de realizada avaliação físico-motora (goniometria, força muscular) seguido de correlação com a escala funcional MFM-32 (Medida de Função Motora). Resultados: Houve significativa queda na qualidade de vida em pacientes Merosina (-) e em outras formas de DMC. O índice de Barthel (IB) apontou \"grave dependência\" final em pacientes merosina (-) e \"moderada dependência\" em outras formas de DMC. A goniometria mostrou diminuição da movimentação global em todos os grupos articulares avaliados em pacientes com merosina (-). Em outras formas de DMC, houve exceção de diminuição apenas em articulação distal de membros superiores. A força de todos os grupos musculares é significativamente afetada em ambos os grupos. Pacientes merosina (-) mostram diminuição significativa de funcionalidade nas três dimensões da escala MFM-32 (D1, D2 e D3), e em outras formas de DMC, apenas diminuição em D2 e D3. Houve moderada correlação positiva entre força muscular e D1 da escala MFM-32, forte correlação positiva entre goniometria e D2 e D3 em pacientes com merosina (-), não havendo correlação entre nenhuma variável e MFM-32 em outras formas de DMC. Conclusão: Pacientes com DMC apresentaram perfil funcional \"gravemente dependente\", com diminuição da qualidade de vida, observada em cinco de oito quesitos do questionário SF-36. A força muscular e a amplitude de movimento articular foram afetadas de forma generalizada em ambos os grupos de pacientes. Pacientes com merosina (-) mostraram-se mais afetados funcionalmente em posturas eretas e transferências, sendo correlacionada positivamente com a força muscular dos grupos dessa tarefa / Congenital Muscular Dystrophy (CMD) is characterized by hypotonia and weakness, motor development delay and muscular contractures. Instruments of clinical assessment, such as functional motor and quality of life scales are essential to quantify the impact of the disease on daily activities of the patient\'s life in addition to helping in the characterization of heterogeneous study groups. As the DMC highly heterogeneous, trace the functional profile of patients with different subtypes would be useful to characterize functional patterns and aid in the treatment by a multidisciplinary team. Objectives: To characterize the functionality and quality of life of children with different subtypes of DMC and to correlate them with the degree of muscle strength and range of motion. Methods: In a sample of 18 patients with CMD (aged 12 + 3.2 years) and 13 patients with other congenital myopathies (aged 13 ± 2.6 years) were applied in three visits (V1, V2 and V3) the SF-36 and Barthel Index (BI), and performed physical-motor assessment (goniometry, muscle strength) followed by correlation with functional scale MFM-32 (motor Function Measure. ). Results: There was a significant decrease in the quality of life in patients Merosin (-) and other forms of CMD. IB indicated \"severe dependence\" final in Merosin patients (-) and \"moderate dependence\" in other forms of CMD. Goniometry showed a decrease of the overall joint movement in all groups evaluated in patients with merosin (-).In other forms of DMC was decreased joint movement in all joint groups, except for the distal joint of the upper limbs. The strength of each muscle group was significantly affected in both groups. Patients merosin (-) show a significant decrease in the functionality on the 3 dimensions of MFM-32 scale (D1, D2, D3) in patients with other forms of DMC only reduction in D2 and D3. There was a moderate positive correlation between muscle strength and D1 of the SF-32 scale, strong positive correlation between goniometry and D2 and D3 in patients with Merosin (-), there was no correlation between this variable and MFM-32 in other forms of CMD. Conclusion: Patients with CMD showed functional profile \"severely dependent\" to low quality of life observed in five of eight areas of the SF-36 questionnaire. Muscle strength and range of motion were affected in a generalized manner in both patient groups. Patients with Merosin (-) are even more affected functionally in standing and transfers being positively correlated with muscle strength of the groups of this task postures
130

The roles of collagens XV and XVIII in vessel formation, the function of recombinant human full-length type XV collagen and the roles of collagen XV and laminin α4 in peripheral nerve development and function

Hurskainen, M. (Merja) 23 November 2010 (has links)
Abstract Transgenic mice were used to evaluate the roles of collagens XV and XVIII in retinal vessel development and to examine the roles of collagen XV and laminin α4 in peripheral nerve development and function. Also, in vitro methods were used to study the functions of recombinant, full-length human collagen XV produced in insect cells. The lack of collagen XVIII alone was found to result in overproliferation of astrocytes in the mouse retina and deficient vascularization of the retina, which was ultimately rescued by the persistent hyaloid vessels. VEGF mRNA expression was appropriately regulated in the retina of the collagen XVIII deficient mice, which also showed reduced susceptibility to oxygen-induced neovascularization. Lack of collagen XV alone had no obvious effect on the mouse eye, but an abnormal migration of astrocytes onto the persistent hyaloid vessels could be seen in mice lacking both collagens XVIII and XV. Recombinant full-length human collagen XV was seen in rotary shadowing EM as an extended protein with numerous kinks and a globular domain at its N-terminus. The mean length of the molecules was 241 nm and they had a tendency to form aggregates. Collagen XV attaches to the collagen binding region of fibronectin and to a lesser extent to vitronectin and laminin. It was rapidly bound to cultured cells with a staining pattern co-localizing with fibronectin. Collagen XV was also found to inhibit the adhesion and migration of cells in vitro. Lack of collagen XV in mice was found to result in ultrastructural abnormalities in the sciatic nerves, such as polyaxonal myelination and more loosely packed C-fibres, mild impairment of BM assembly and mild motor dysfunction with a lower sensory nerve conduction velocity. Polyaxonal myelination and a failure in the segregation of axons were evident in laminin α4 null mice, which also had diminished amounts of C-fibres, BM abnormalities, diminished myelin and a greater myelin period compared with wild-type mice. They performed poorly in the round beam test and showed diminished compound muscle action potentials. A simultaneous lack of collagen XV and laminin α4 resulted in a permanent defect in the segregation of axons and C-fibre development. The performance of the double null mice on the round beam was poor relative to the other genotypes. / Tiivistelmä Tässä väitöskirjatyössä on tutkittu kollageenien XV ja XVIII merkitystä silmän verkkokalvon verisuonituksen kehittymiselle sekä kollageeni XV:n ja laminiini α4:n merkitystä ääreishermon kehittymiselle ja toiminnalle käyttäen hyväksi muuntogeenisiä hiiriä. Lisäksi tässä työssä on käytetty in vitro –menetelmiä hyönteissoluissa yhdistelmä-DNA-tekniikalla tuotetun kollageeni XV:n toiminnan tutkimiseksi. Kollageeni XVIII:n puutteen todettiin johtavan verkkokalvon astrosyyttien määrän lisääntymiseen sekä verkkokalvon suonituksen kehittymiseen epänormaalilla tavalla lasiaissuonista, jotka eivät olleetkaan hävinneet kehityksen aikana. VEGF:n lähetti-RNA:n ilmentyminen oli asianmukaisesti säädelty eri verkkokalvon alueilla kollageeni XVIII:n suhteen poistogeenisillä hiirillä, joilla kehittyi myös vähemmän uudissuonia matalalle hapen osapaineelle altistamisen jälkeen. Kollageeni XV:n puute ei johtanut havaittaviin muutoksiin silmässä, mutta molempien kollageenien XV ja XVIII puuttuessa havaittiin silmässä epänormaalia astrosyyttien soluvaellusta lasiaissuonten päälle. Tässä väitöskirjatyössä osoitetaan, että yhdistelmä-DNA-tekniikalla tuotettu kokopitkä ihmisen kollageeni XV näytti elektronimikroskopiassa pitkältä molekyyliltä, jonka pituus oli keskimäärin 241 nm ja joka sitoutui helposti toisiin kollageeni XV -molekyyleihin. Kollageeni XV sitoutuu fibronektiinin kollageenia sitovaan osaan sekä vitronektiiniin ja laminiiniin. Viljeltyihin soluihin kollageeni XV sitoutui siten, että vasta-ainevärjäyksellä todettiin sen paikallistuvan samoille alueille fibronektiinin kanssa. Kollageeni XV:n todettiin myös vähentävän solujen kiinnittymistä ja liikkumista. Hiirissä kollageeni XV:n puutoksen todettiin johtavan iskiahermoissa polyaksonaaliseen myelinisaatioon, C-säikeiden lievään kehityshäiriöön, tyvikalvon koostumuksen häiriöön, lieviin motorisiin vaikeuksiin ja matalampaan tuntohermojen johtonopeuteen. Laminiini α4 –puutteisilla hiirillä oli todettavissa myös polyaksonaalista myelinisaatiota ja lisäksi häiriö aksonien erottelussa. Niiden hermoista löytyi myös tyvikalvon epämuodostumia, vähemmän myeliiniä ja C-säikeitä sekä suuremmat myeliinijaksot verrattuna villityypin hiiriin. Ne selviytyivät huonosti kävelytestissä ja niiden lihasten aktiopotentiaalit olivat pienemmät kuin kontrollihiirillä. Samanaikainen kollageeni XV:n ja laminiini α4:n puutos johti pysyvään aksonien erottelun ja C-säikeiden kehittymisen häiriöön. Kävelytestissä tuplapoistogeeniset hiiret selviytyivät huonoiten muihin genotyyppeihin verrattuna.

Page generated in 0.0919 seconds