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  • 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.
31

Lesões ulcerativas cutâneas em frangos de corte: estudo histopatológico e epidemiológico

Sesterhenn, Renata January 2013 (has links)
Em função de modificações no processo de criação em escala industrial, associado à expansão do setor avícola nas áreas de genética, nutrição e sanidade, as lesões cutâneas em frangos de corte vêm tornando-se cada vez mais importantes. Na atualidade, as principais doenças que afetam a pele de frangos são a celulite, a varíola aviária, o querato-acantoma (QA) ou carcinoma dérmico de células escamosas (CDCE) e as dermatites inespecíficas, estas últimas geralmente associadas a traumatismos. A classificação das doenças cutâneas é imprecisa, uma vez que os critérios de inspeção tendem a agrupar essas lesões cutâneas nas carcaças de frangos de corte em uma única categoria denominada de “dermatose”. As lesões ulcerativas na pele de frangos de corte são causas comuns de condenação total ou parcial de carcaças em matadouros-frigoríficos. O querato-acantoma é uma das causas mais frequentes dessas lesões, sendo de etiologia desconhecida. Por outro lado, lesões ulcerativas macroscopicamente semelhantes às do querato-acantoma e causadas por granulomas do tipo corpo estranho, possivelmente de origem vegetal, vêm sendo observadas em aves abatidas em alguns matadouros-frigoríficos no estado do Rio Grande do Sul (Brasil). Com base nessas premissas, o objetivo desse trabalho foi avaliar histologicamente e analisar os fatores epidemiológicos envolvidos no aparecimento das lesões ulcerativas cutâneas: querato-acantoma e dermatite granulomatosa por corpo estranho (DGCE) em frangos de corte abatidos em matadouros-frigoríficos sob inspeção federal e estadual. Foram analisadas 363 amostras com lesões ulcerativas, de um total de 1.373.989 aves visualizadas. Destas, 169 carcaças foram diagnosticadas como querato-acantoma, representando uma prevalência de 0,012% e 210 carcaças foram diagnosticadas como dermatite granulomatosa por corpo estranho, representando 0,015%, A prevalência encontrada no presente trabalho para QA é similar aos valores encontrados por autores, já a prevalência encontrada para DGCE foi superior à relatada em 2004. Se verificou uma maior prevalência de QA em frangos abatidos em matadouros-frigoríficos sob inspeção federal e mais casos de DGCE nos abatidos em matadouros-frigoríficos sob inspeção estadual. A localização mais frequente das úlceras foi o dorso para o querato-acantoma e o peito para a DGCE. As lesões ulcerativas disseminadas na carcaça foram 100 % diagnosticadas como querato-acantoma. Macroscopicamente as lesões únicas podem ser tanto diagnósticas para querato-acantoma como dermatite granulomatosa por corpo estranho, sendo necessário o exame histopatológico para o diagnóstico definitivo. Houve grande variabilidade dos fatores epidemiológicos envolvidos no aparecimento de lesões ulcerativas de pele, indicando necessidade de novas análises para aumentar a amostragem das amostras. / Due to changes in the husbandry process on an industrial scale, associated with the expansion of the poultry sector in the areas of genetics, nutrition and health, the skin lesions have become increasingly important. At present, the major diseases that affect the skin in broilers are cellulite, fowl pox, the keratoacantoma (KA) or dermal squamous cell carcinoma (DSCC) and nonspecific dermatitis, the latter generally associated with trauma. The classification of skin diseases is inaccurate, since the inspection tend to group these skin lesions in carcasses of broilers in a single category called "dermatosis". The ulcerative skin lesions of broilers are common causes of total or partial condemnation of carcasses in slaughterhouses. The keratoacantoma is one of the most frequent causes of these injuries, and of unknown etiology. On the other hand, ulcerative lesions macroscopically similar to the keratoacantoma and granulomas caused by foreign body, possibly of plant origin, has been observed in some birds slaughtered in slaughterhouse in Rio Grande do Sul (Brazil). Based on these premises, the aim of this study was to histologically evaluate and analyze the epidemiological factors involved in the appearance of ulcerative skin: keratoacantoma and foreign body granulomatous dermatitis (FBGD) in broilers slaughtered in slaughterhouses under federal and state inspection. 363 samples were analyzed with ulcerative lesions, a total of 1,373,989 poultry displayed. Of these, 169 carcasses were diagnosed as keratoacantoma, representing a prevalence of 0.012% and 210 carcasses were diagnosed as granulomatous dermatitis foreign body, representing 0.015%. The prevalence founded in the present work to KA is within the range found by authors in previous works, since the prevalence DSCC was higher than that reported in 2004. There was a higher prevalence of KA in slaughter plants under federal inspection and more cases of DSCC in slaughter plants under state inspection. The most frequent location of ulcers was the back and chest for keratoacantoma for DSCC. Ulcerative lesions disseminated in the housing 100% were diagnosed as keratoacanthoma. Grossly, the lesions can be both unique diagnostic for keratoacanthoma as granulomatous dermatitis, requiring histopathology for definitive diagnosis. With this work, it was concluded that new skin lesions should be analyzed, to increase the sampling of specimens, decreasing the variability among the predisposing skin lesions.
32

Lesões ulcerativas cutâneas em frangos de corte: estudo histopatológico e epidemiológico

Sesterhenn, Renata January 2013 (has links)
Em função de modificações no processo de criação em escala industrial, associado à expansão do setor avícola nas áreas de genética, nutrição e sanidade, as lesões cutâneas em frangos de corte vêm tornando-se cada vez mais importantes. Na atualidade, as principais doenças que afetam a pele de frangos são a celulite, a varíola aviária, o querato-acantoma (QA) ou carcinoma dérmico de células escamosas (CDCE) e as dermatites inespecíficas, estas últimas geralmente associadas a traumatismos. A classificação das doenças cutâneas é imprecisa, uma vez que os critérios de inspeção tendem a agrupar essas lesões cutâneas nas carcaças de frangos de corte em uma única categoria denominada de “dermatose”. As lesões ulcerativas na pele de frangos de corte são causas comuns de condenação total ou parcial de carcaças em matadouros-frigoríficos. O querato-acantoma é uma das causas mais frequentes dessas lesões, sendo de etiologia desconhecida. Por outro lado, lesões ulcerativas macroscopicamente semelhantes às do querato-acantoma e causadas por granulomas do tipo corpo estranho, possivelmente de origem vegetal, vêm sendo observadas em aves abatidas em alguns matadouros-frigoríficos no estado do Rio Grande do Sul (Brasil). Com base nessas premissas, o objetivo desse trabalho foi avaliar histologicamente e analisar os fatores epidemiológicos envolvidos no aparecimento das lesões ulcerativas cutâneas: querato-acantoma e dermatite granulomatosa por corpo estranho (DGCE) em frangos de corte abatidos em matadouros-frigoríficos sob inspeção federal e estadual. Foram analisadas 363 amostras com lesões ulcerativas, de um total de 1.373.989 aves visualizadas. Destas, 169 carcaças foram diagnosticadas como querato-acantoma, representando uma prevalência de 0,012% e 210 carcaças foram diagnosticadas como dermatite granulomatosa por corpo estranho, representando 0,015%, A prevalência encontrada no presente trabalho para QA é similar aos valores encontrados por autores, já a prevalência encontrada para DGCE foi superior à relatada em 2004. Se verificou uma maior prevalência de QA em frangos abatidos em matadouros-frigoríficos sob inspeção federal e mais casos de DGCE nos abatidos em matadouros-frigoríficos sob inspeção estadual. A localização mais frequente das úlceras foi o dorso para o querato-acantoma e o peito para a DGCE. As lesões ulcerativas disseminadas na carcaça foram 100 % diagnosticadas como querato-acantoma. Macroscopicamente as lesões únicas podem ser tanto diagnósticas para querato-acantoma como dermatite granulomatosa por corpo estranho, sendo necessário o exame histopatológico para o diagnóstico definitivo. Houve grande variabilidade dos fatores epidemiológicos envolvidos no aparecimento de lesões ulcerativas de pele, indicando necessidade de novas análises para aumentar a amostragem das amostras. / Due to changes in the husbandry process on an industrial scale, associated with the expansion of the poultry sector in the areas of genetics, nutrition and health, the skin lesions have become increasingly important. At present, the major diseases that affect the skin in broilers are cellulite, fowl pox, the keratoacantoma (KA) or dermal squamous cell carcinoma (DSCC) and nonspecific dermatitis, the latter generally associated with trauma. The classification of skin diseases is inaccurate, since the inspection tend to group these skin lesions in carcasses of broilers in a single category called "dermatosis". The ulcerative skin lesions of broilers are common causes of total or partial condemnation of carcasses in slaughterhouses. The keratoacantoma is one of the most frequent causes of these injuries, and of unknown etiology. On the other hand, ulcerative lesions macroscopically similar to the keratoacantoma and granulomas caused by foreign body, possibly of plant origin, has been observed in some birds slaughtered in slaughterhouse in Rio Grande do Sul (Brazil). Based on these premises, the aim of this study was to histologically evaluate and analyze the epidemiological factors involved in the appearance of ulcerative skin: keratoacantoma and foreign body granulomatous dermatitis (FBGD) in broilers slaughtered in slaughterhouses under federal and state inspection. 363 samples were analyzed with ulcerative lesions, a total of 1,373,989 poultry displayed. Of these, 169 carcasses were diagnosed as keratoacantoma, representing a prevalence of 0.012% and 210 carcasses were diagnosed as granulomatous dermatitis foreign body, representing 0.015%. The prevalence founded in the present work to KA is within the range found by authors in previous works, since the prevalence DSCC was higher than that reported in 2004. There was a higher prevalence of KA in slaughter plants under federal inspection and more cases of DSCC in slaughter plants under state inspection. The most frequent location of ulcers was the back and chest for keratoacantoma for DSCC. Ulcerative lesions disseminated in the housing 100% were diagnosed as keratoacanthoma. Grossly, the lesions can be both unique diagnostic for keratoacanthoma as granulomatous dermatitis, requiring histopathology for definitive diagnosis. With this work, it was concluded that new skin lesions should be analyzed, to increase the sampling of specimens, decreasing the variability among the predisposing skin lesions.
33

Biomaterials and the Foreign Body Reaction: Surface Chemistry Dependent Macrophage Adhesion, Fusion, Apoptosis, and Cytokine Production

Jones, Jacqueline Ann 16 April 2007 (has links)
No description available.
34

Development and Characterization of Anti-Inflammatory Coatings for Implanted Neural Probes

Zhong, Yinghui 21 November 2006 (has links)
Stable single-unit recordings from the nervous system using microelectrode arrays can have significant implications for the treatment of a wide variety of sensory and movement disorders. However, the long-term performance of the implanted neural electrodes is compromised by the formation of glial scar around these devices, which is a typical consequence of the inflammatory tissue reaction to implantation-induced injury in the CNS. The glial scar is inhibitory to neurons and forms a barrier between the electrode and neurons in the surrounding brain tissue. Therefore, to maintain long-term recording stability, reactive gliosis and other inflammatory processes around the electrode need to be minimized. This work has succeeded in the development of neural electrode coatings that are capable of sustained release of anti-inflammatory agents while not adversely affecting the electrical performance of the electrodes. The effects of coating methods, initial drug loadings on release kinetics were investigated to optimize the coatings. The physical properties of the coatings and the bioactivity of released anti-inflammatory agents were characterized. The effect of the coatings on the electrical property of the electrodes was tested. Two candidate anti-inflammatory agents were screened by evaluating their anti-inflammatory potency in vitro. Finally, neural electrodes coated with the anti-inflammatory coatings were implanted into rat brains to assess the anti-inflammatory potential of the coatings in vivo. This work represents a promising approach to attenuate astroglial scar around the implanted silicon neural electrodes, and may provide a promising strategy to improve the long-term recording stability of silicon neural electrodes.
35

Telas depolipropileno revestidas por quitosana/polietilenoglicol na ocorrência de aderências peritoniais: Estudo experimental em ratas / Polypropylene meshes coated by chitosan/polyethyelene glycol in event of peritoneal adhesions: experimental study in females rats

RODRIGUES, Danilo Ferreira 25 February 2011 (has links)
Made available in DSpace on 2014-07-29T15:07:34Z (GMT). No. of bitstreams: 1 Dissert-Danilo Ferreira Rodrigues.pdf: 452744 bytes, checksum: 0d66f9b822194b140597d873ca8c4a8c (MD5) Previous issue date: 2011-02-25 / Peritoneal adhesions are highly important in clinical and surgical practice because of the potential to cause sequelae such as chronic abdominal pain, infertility and bowel obstruction; thus, preventing the formation of this process becomes a challenge for surgeons. Due to biocompatibility, bioabsorption, healing and antimicrobial properties, chitosan is a polymer which has aroused interest of researchers studying the prevention of peritoneal adhesions. The objective of this research was to determine whether the intraperitoneal implantation of polypropylene mesh coated with a film of chitosan/polyethylene glycol is effective for the prevention of adhesions in rats with induced abdominal defects. We sought to further characterize the tissue reactions in acute and chronic phases of the inflammation process, and the tissue repair processes triggered by this biomaterial and the polypropylene mesh without coating. Defect of about 1cm was made in the abdominal wall, with reference to anatomical aponeurosis of the fascia of the rectus abdominis and obliquus externus abdominis muscles, followed by the implantation of polypropylene meshes coated with chitosan / polyethylene glycol (QP Group, n= 12) and uncoated polypropylene meshes (PP group, n= 12). Six animals from each group were euthanized at four and 45 days after implantation and the involvement of the mesh area by the adhesion, the type of adhesion, the inflammation process and tissue repair, and the quantification and characterization of collagen fibers were evaluated. The average of the meshes involved by adhesions in the QP and PP groups was 39.088% and 84.024%, respectively, and the structure involved in abdominal adhesions in the QP group usually consisted of the omentum around the implant, while in the PP group, adhesions were usually on the surface of the mesh. After four days of surgery, the amount of mononuclear cells was lower in QP, but the amount of polymorphonuclear cells, fibrin and collagen fibers was in greater quantity in this group; besides, the later variable showed better spatial organization. After 45 days of biomaterials implantation, there was a reduction in the amount of inflammatory cells, and spatial organization of collagen fibers in the QP group remained strong. It is concluded that the meshes coated with the film based on chitosan/polyethylene glycol did not prevent adhesion formation, but significantly minimized the seriousness of this process. In the acute phase of inflammation and tissue repair, the foreign body reaction was less intense in the group receiving the coated polypropylene mesh, but the tissue reactions caused by the studied biomaterials were similar to the chronic phase. The mesh coated with film-based chitosan/polyethylene glycol stimulated higher production and better orientation of collagen type I in the acute phase of inflammation and tissue repair, and better orientation of collagen fibers in the chronic phase of this process. / As aderências peritoniais possuem grande importância na prática clínico-cirúrgica pela possibilidade de causarem sequelas como dor abdominal crônica, infertilidade e obstrução intestinal, portanto a prevenção do desenvolvimento deste processo torna-se um desafio para os cirurgiões. Devido às propriedades de biocompatibilidade, bioabsorção, cicatrizante e antimicrobiana, a quitosana é um polímero que tem despertado interesse no estudo da prevenção de aderências peritoniais. O objetivo com esta pesquisa foi verificar se o implante intraperitonial de telas de polipropileno revestidas com o filme de quitosana/polietilenoglicol é eficiente na prevenção de aderências em ratos com defeitos abdominais induzidos, além de caracterizar as reações teciduais nas fases aguda e crônica do processo de inflamação e reparo tecidual desencadeadas por este biomaterial, e a tela de polipropileno sem revestimento. Foram realizados defeitos na parede abdominal de aproximadamente 1cm, tendo como referência anatômica a aponeurose das fáscias externas dos músculos reto abdominal e oblíquo abdominal externo, seguida da implantação de telas de polipropileno revestidas com quitosana/polietilenoglicol (Grupo QP, n=12) e telas de polipropileno sem revestimento (Grupo PP, n=12). Seis animais de cada grupo foram submetidos à eutanásia aos quatro e 45 dias após o implante, e foram avaliadas a área de envolvimento da tela pela aderência, o tipo de aderência, o processo de inflamação e reparo tecidual, além da quantificação e tipificação de fibras colágenas. A média das telas envolvidas pelas aderências no grupo QP foi de 39,088% e de 84,024% no grupo PP e a estrutura abdominal envolvida nas aderências no grupo QP geralmente consistiam pelo omento ao redor do implante, no grupo PP, as aderências geralmente estavam na superfície da tela. Após quatro dias do procedimento cirúrgico, a quantidade de células mononucleares foi menor no grupo QP, porém a quantidade de células polimorfonucleares, fibrina e fibras colágenas estavam em maior quantidade nesse grupo, além desta última variável apresentar melhor organização espacial. Após 45 dias da implantação dos biomateriais, houve a redução na quantidade de células inflamatórias, e a organização espacial das fibras colágenas no grupo QP foi permaneceu acentuada. Conclui-se que as telas revestidas com o filme à base de quitosana/polietilenoglicol não preveniram a formação de aderências, porém minimizaram significativamente a gravidade deste processo. Na fase aguda do processo de inflamação e reparo tecidual, a reação de corpo estranho foi menos intensa no grupo que recebeu a tela de polipropileno com revestimento, porém as reações teciduais provocadas pelos biomateriais analisados foram similares na fase crônica. A tela revestida com o filme a base de quitosana/polietilenoglicol estimulou a maior produção e melhor orientação de fibras colágenas tipo I na fase aguda do processo de inflamação e reparação tecidual, e melhor orientação de fibras colágenas na fase crônica deste processo.
36

[en] AUTOMATED SYSTEM FOR MAPPING FERROMAGNETIC FOREIGN BODIES USING GMI MAGNETOMETER / [pt] SISTEMA AUTOMATIZADO PARA MAPEAMENTO DE CORPOS ESTRANHOS FERROMAGNÉTICOS UTILIZANDO MAGNETÔMETRO GMI

BRYAN RODRIGUES CUPELLO DE OLIVEIRA 01 February 2021 (has links)
[pt] A informação sobre o posicionamento de objetos estranhos no interior do corpo humano é essencial para a sua eficiente remoção cirúrgica. Entretanto, os métodos convencionalmente utilizados não fornecem informação suficiente sobre a localização do objeto metálico para garantia de sucesso cirúrgico. No presente trabalho foi desenvolvido um sistema automatizado para mapear a densidade de fluxo magnético estático produzido por corpos ferromagnéticos posicionados em variados graus de liberdade 3D, utilizando um sensor de baixo custo, baseado no fenômeno da magnetoimpedância gigante (GMI - Giant Magnetoimpedance), que detecta somente campos magnéticos variantes no tempo. Assim, as medições automatizadas foram realizadas com a amostra em movimento a uma velocidade constante. Por meio de modelagens computacionais do campo magnético gerado foi possível reproduzir o comportamento da densidade de fluxo magnético gerado por uma fonte de campo magnético como a agulha retilínea utilizada nas medições in vitro. O software considerou as características do sensor GMI utilizado e a condição de medição com a fonte magnética em movimento. Os resultados da simulação foram validados por meio de comparações com os resultados experimentais, possibilitando a solução do problema direto com a caracterização da configuração espacial da densidade de fluxo magnético para variados posicionamentos da fonte magnética em relação ao sensor magnético GMI. Com a validação dos resultados simulados, os mesmos podem ser empregados no desenvolvimento de procedimento para solução do problema inverso de imageamentos clínicos utilizando o sensor GMI de baixo custo, limitado a medições magnéticas variantes no tempo, realizados para detecção e posicionamento de corpos estranhos que geram campos magnéticos estáticos. / [en] Information about the positioning of foreign objects inside the human body is essential for its efficient surgical removal. However, the methods conventionally used do not provide sufficient information on the location of the metallic object to guarantee surgical success. In the present work, an automated system was developed to map the static magnetic flux density produced by ferromagnetic bodies positioned in varying degrees of 3D freedom, using a low-cost sensor based on the giant magnetoimpedance phenomenon (GMI - Giant Magnetoimpedance), which detects only time-varying magnetic fields. Thus, automated measurements were performed with the sample moving at a constant speed. Through computational modeling of the generated magnetic field, it was possible to reproduce the behavior of the magnetic flux density generated by a magnetic field source, such as the straight needle used in in vitro measurements. The software considered the GMI sensor s characteristics and the measurement condition with the magnetic source in motion. The simulation results were validated through comparisons with the experimental results, enabling the solution of the direct problem with the characterization of the spatial configuration of the magnetic flux density for various magnetic source positions in relation to the GMI magnetic sensor. With the validation of the simulated results, they can be used in the development of a procedure to solve the inverse problem of clinical imaging using the low-cost GMI sensor, limited to time-varying magnetic measurements, performed for the detection and positioning of foreign bodies that generate static magnetic fields.
37

[pt] ESTRATÉGIA HÍBRIDA DAS ABORDAGENS QUALITY BY DESIGN E FAILURE MODE AND EFFECT ANALYSIS PARA APLICAÇÃO NO DESENVOLVIMENTO DE TECNOLOGIA BIOMÉDICA / [en] HYBRID STRATEGY OF QUALITY BY DESIGN AND FAILURE MODE AND EFFECT ANALYSIS APPROACHES FOR APPLICATION IN BIOMEDICAL TECHNOLOGY DEVELOPMENT

MARIA ALEXANDRA MATALLANA CASTELLANOS 12 January 2023 (has links)
[pt] Este trabalho apresenta a estratégia híbrida das abordagens Quality by Design e Failure Mode and Effects Analysis para aplicação no desenvolvimento de tecnologia biomédica. A qualidade e a gestão de riscos precisam evoluir com o avanço do desenvolvimento farmacêutico e tecnológico na saúde, permitindo um maior controle dos processos de fabricação de cada dispositivo biomédico. A Análise de Modo e Efeito de Falha (FMEA) tem sido amplamente utilizada na saúde para garantir a qualidade dos produtos fabricados. Ela se dedica a prevenir eventos ou incidentes adversos, identificando falhas para priorizar o risco e otimizando recursos, para uma melhor qualidade em dispositivos ou equipamentos médicos. A Qualidade por Projeto (QbD), por sua vez, tem sido aplicada na indústria farmacêutica para garantir a qualidade dos produtos desde a fase de desenvolvimento. Os resultados obtidos com a estratégia híbrida desenvolvida determinaram os atributos da qualidade e os parâmetros do processo mais críticos para aplicação no desenvolvimento de sistema de medição para localização de corpo estranho metálico em pacientes. A abordagem QbD-FMEA contribuiu para a determinação mais adequada e abrangente dos elementos críticos mais relevantes e associadas ações preventivas do que o emprego dessas sistemáticas isoladamente. / [en] This work presents the hybrid strategy of Quality by Design and Failure Mode and Effects Analysis approaches for application in biomedical technology development. Quality and risk management need to evolve with the advancement of pharmaceutical and technological development in healthcare, allowing greater control of the manufacturing processes of each biomedical device. Failure Mode and Effect Analysis (FMEA) has been widely used in healthcare to ensure the quality of manufactured products. It is dedicated to preventing adverse events or incidents, identifying failures to prioritize risk, and optimizing resources for better medical devices or equipment quality. In turn, Quality by Design (QbD) has been applied in the pharmaceutical industry to ensure product quality from the development phase. The results obtained with the developed hybrid strategy determined the most critical quality attributes and process parameters for application in developing a measurement system for metallic foreign body location in patients. The hybrid QbD-FMEA approach contributed to a more adequate and comprehensive determination of the most relevant critical elements, associating with preventive actions, than the isolated use of these approaches.
38

Fremdkörperaspiration bei Kindern

Link, Sarah 07 May 2012 (has links) (PDF)
In der vorliegenden Arbeit wurden retrospektiv 66 Fälle stattgehabter Fremdkörperaspirationen aus den kinderchirurgischen Akten und Ambulanzakten der Jahre 1997 bis 2008 des Universitätsklinikums Leipzig rekonstruiert und im Hinblick auf die nachfolgend genannten Kriterien statistisch ausgewertet: Geschlecht und Alter der Kinder, Indikation zur Bronchoskopie, Einweisungsart, Dauer bis zur Diagnosestellung, endoskopische Sichtbarkeit des Fremdkörpers, Entfernungsschritte, erforderliche Nachbeatmung, Anhalt durch Röntgenbefund, auskultatorischer Anhalt, anamnestischer Anhalt, Eigen- oder Fremdanamnese, das Vorhandensein von Husten und die Dauer bis zur Entlassung aus dem Krankenhaus. Die Kriterien wurden standardisiert und mittels des Statistikprogramms SPSS 18 ausgewertet. Anhand der ausgewerteten Daten wurde ein Algorithmus zur innerklinischen Vorgehensweise bei Verdacht auf Fremdkörperaspiration erstellt, welcher eine interdisziplinäre Arbeitsrichtlinie (Standard Operation Procedure, SOP) für andere Kinderzentren liefern kann. Das geschärfte Bewusstsein für die Häufigkeit einer Fremdkörperaspiration vor allem bei Kindern und die damit verbundene problemorientierte Diagnostik und Therapie soll mit einer einschlägigen Arbeitsrichtlinie in Zukunft mehr Kindern als bisher zunutze gemacht werden.
39

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.
40

Gewebereaktionen auf nicht-metallische kardiovaskuläre Implantatmaterialien zum Einsatz bei der Therapie angeborener Herzfehler / Tissue reactions to non-metallic cardiovascular implants for the treatment of congenital heart defects

Hüll, Stephanie 08 December 2016 (has links)
Bei angeborenen Herzfehlern, die bei 1 bis 1,2 % aller Lebendgeburten auftreten und so-mit die häufigste behandlungsbedürftige Organfehlbildung darstellen, kommen regelhaft kardiovaskuläre Implantate im Rahmen der chirurgischen bzw. interventionellen Therapie zum Einsatz. Hierzu zählen u. a. Shunts, Patches und Okkluder, die aus verschiedenen Implantatmaterialien hergestellt werden. Das Ziel dieser Arbeit bestand darin – basierend auf histologischen Untersuchungen – Unterschiede bzw. Gemeinsamkeiten bezüglich der Biokompatibilität nicht-metallischer Implantatmaterialien zu prüfen, da eine bewusste Materialauswahl kardiovaskulärer Implantate zur Therapie angeborener Herzfehler zu besseren Langzeitergebnissen der Implantate beitragen kann. Untersucht wurden Implantate, die im Rahmen von Korrekturoperationen entnommen wurden und anschließend im Forschungslabor für Pädiatrische Kardiologie und Intensivmedizin der Universitätsmedizin Göttingen ausgewertet wurden: Shunts aus PTFE (n = 21, durchschnittliche Implantationszeit: 18 Monate), Patches aus PTFE (n = 13, durchschnittliche Implantationszeit: 247 Monate) und Polyester (n = 4, durchschnittli¬che Implantationszeit: 321 Monate) sowie Okkluder aus PTFE (n = 3, durchschnittliche Implantationszeit: 74 Monate), Polyester (n = 9, durchschnittliche Implantationszeit: 30 Monate) und PVA (n = 2, durchschnittliche Implantationszeit: 23 Monate). Zur Herstellung histologischer Präparate wurden metallhaltige Implantate (Okkluder) sowie solche mit bereits makroskopisch sichtbarer Verkalkung in Methylmethacrylat-Kunstharz eingebettet und anschließend gesägt und geschliffen, sodass sie lichtmikroskopisch ausgewertet werden konnten. Die anderen Implantate wurden in Paraffin eingebettet und geschnitten. Neben konventionellen Färbungen zur Übersicht und Darstellung von Verkalkungen wurden immunhistochemische Färbungen eingesetzt. Unabhängig vom Implantatmaterial konnte regelhaft eine endothelialisierte und neovaskularisierte Pseudointima, hauptsächlich am ehesten aus Myofibroblasten und Fibroblasten bestehend, dargestellt werden. Das im Implantatmaterial neu gebildete Gewebe bestand hauptsächlich aus Fibroblasten und war neovaskularisiert. Implantatassoziierte, chronische Entzündungsreaktionen – getragen durch Makrophagen und Lymphozyten – sowie Fremdkörperreaktionen – getragen durch FKR – waren bei den Polyester- und PVA-Implantaten stärker ausgeprägt als bei den PTFE-Implantaten. Verkalkungen in Pseudointima- und Implantatgewebe wurden bei den Polyester-Implantaten ab einer Implantationszeit von 3 Jahren und 4 Monaten, bei den PTFE-Implantaten ab einer Implantationszeit von 5 Jahren und 10 Monaten beobachtet. Die durch Polyester hervorgerufene, stärker ausgeprägte Entzündungsreaktion ist als Ursache der zu einem früheren Zeitpunkt einsetzenden Verkalkung von Polyester-Implantaten anzusehen. Während bei den Polyester-Implantaten häufig eher ungleichmäßig verteilte und unregelmäßig geformte, punktförmige Verkalkungen bis hin zu kleinen Kalkaggregaten in Pseudointima- und Implantatgewebe vorhanden waren, wiesen die PTFE-Implantate zumeist gleichmäßige, großflächig-konfluierende Verkalkungen auf. Es konnte gezeigt werden, dass bei Implantaten, die Polyester- oder PTFE-Anteile enthal¬ten, mittelfristig mit der Entwicklung von lokalen Verkalkungen zu rechnen ist, die im Langzeitverlauf zu Komplikationen führen können. Dies muss bei der Implantatauswahl beachtet werden. Möglicherweise kann in Zukunft durch die Entwicklung neuartiger Materialien eine Verminderung der Verkalkungstendenz, zum Beispiel durch Biodegra¬dierbarkeit des Implantatmaterials, erreicht werden.

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