Microglia, the resident immune cells of the central nervous system (CNS), become activated in response to danger signals given out by other cells when homeostasis has been disturbed. Microglial activation is a multifaceted phenomenon that includes numerous distinct phenotypes. The type of activation often influences the survival of surrounding CNS tissue, and thus gaining a better understanding of how microglial activation is regulated has important therapeutic implications. Currently, it is known that the phenotype of activated microglia depends on both the type of CNS insult and the specific activating agent. The aim of this thesis was to investigate the potential involvement of other determining factors. Extrinsic regulators of microglial activation, including the severity of CNS insult and the stimulation strength of activating agents, were examined. Intrinsic differences among different microglial populations, namely differences in region of origin and age of origin, were also investigated. To study microglial behavior without interference from other cells, rat primary cultures were used as the system of study. With regard to extrinsic factors, it was found that different severities of hypoxic neuronal injury induced distinct microglial phenotypes. Among the activating agents released by injured neurons, adenosine 5-triphosphate (ATP) was studied in isolation and was found to induce trophic and toxic effectors in microglia depending on the strength of ATP stimulation. In regards to intrinsic factors, it was found that microglia derived from different regions of the brain had distinct responses to activators, with cortical and hippocampal microglia generating more toxic responses than brainstem, striatal, and thalamic microglia. Microglia derived from various ages of origin also responded differentially to activators, with neonatal and aged microglia being more reactive than microglia derived from other age groups. Together, the results here present several novel concepts, that the phenotype of activated microglia are dependent not only on the type of activating stimulus, but the strength of that stimulus, and that in addition to stimuli from other cells, the regional and age differences among microglia themselves are also crucial in determining their activation phenotype.

Diss. (sammanfattning) Stockholm : Karol. inst., 2001. / Härtill 6 uppsatser.

Thesis (Ph. D.)--Cornell University, May, 2007. / Vita. Includes bibliographical references (leaves 324-341).

Frankfurt (Main), Univ., Diss., 2004.

University, Diss., 2003. --(Nicht für d. Austausch)--Frankfurt (Main). / Zeichendarst. im Sachtitel teilw. nicht vorlagegemäß wiedergegeben.

Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2017-07-21T11:12:03Z No. of bitstreams: 1 texto completo.PDF: 336431 bytes, checksum: 887553804bbe90d701abf5a9a80de79d (MD5) / Made available in DSpace on 2017-07-21T11:12:03Z (GMT). No. of bitstreams: 1 texto completo.PDF: 336431 bytes, checksum: 887553804bbe90d701abf5a9a80de79d (MD5) Previous issue date: 2001-10-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Foram avaliadas pela técnica de ATP-bioluminescência i) a qualidade microbiológica da água do manancial de captação para tratamento na ETA/UFV, da água de resfriamento de amônia e da água industrial de uso em um laticínio, ii) a adesão de Escherichia coli K12 e de esporos de Bacillus sporothermodurans, em suspensões, contendo cerca de 10 4 e 10 6 UFC/mL, em aço inoxidável e em polietileno de baixa densidade a 37°C e tempo de adesão de 24h. e, iii) o procedimento de higienização em superfícies de caminhão tanque, tanque de resfriamento de leite cru, tanque de equilíbrio do pasteurizador, desnatadeira, tanque de armazenamento de leite pasteurizado e tanque de equilíbrio para empacotamento de leite pasteurizado. Nas águas foram efetuadas, também, as contagens de mesófilos aeróbios, expressos em UFC/mL e coliformes totais, expressos em NMP/100mL. Nas superfícies foram determinados os números de mesófilos aeróbios aderidos, expressos em UFC/cm 2 . Foi utilizado o luminômetro UNILITEX-cel (BIOTRACE), para os testes de determinação de ATP, expressos em Unidades Relativas de Luz (URL), incluindo ATP total e livre. Em relação à água industrial, houve a concordância entre os métodos de bioluminescência e de contagem de mesófilos aeróbios e coliformes totais. As amostras de água de manancial e de resfriamento não apresentaram diferença (p<0,05), pelo teste de Tukey, para as quantidades de ATP total, livre e também para as contagens microbianas. Constataram-se concentrações de ATP microbiano diferentes para essas amostras de água. Os resultados indicam que teste de ATP total é mais recomendado e sugerem que qualidade físico-química da água diminui a medida de luz. A bioluminescência não foi apropriada para avaliar a presença de esporos de B. sporothermodurans e de E. coli nas superfícies avaliadas. A determinação das URL foi afetada pelas condições de adesão da E. coli. Os resultados mostram que tanto a concentração de ATP total e a contagem de mesófilos aeróbios foram diferentes (p<0,05) quando se comparou antes - 9772 URL e 1,20 X10 3 UFC/cm 2 - e após - 2511 URL e 1,10x10 1 UFC/cm 2 - o procedimento de higienização. A bioluminescência considerou 100% das superfícies em condições higiênicas insatisfatórias e contagem em placas apenas detectou 50%, considerando a recomendação da APHA e 28% a recomendação da OMS. Não houve concordância entre bioluminescência e a contagem microbiana na classificação quanto às condições higiênicas das diferentes superfícies. Observou-se grande variação na leitura de URL, sugerindo a necessidade de se efetuar mais de uma análise na superfície avaliada. A técnica de ATP-bioluminescência pode ser usada como indicadora das boas condições de limpeza, não apresentando relação com a contagem microbiana, indicando também a possibilidade de adesão microbiana e formação de biofilmes. / ATP-bioluminescence techniques were used to evaluate i) the microbiological quality of the ETA/UFV, treatment water, ammonia-cooling water and industrial water at a dairy, ii) the adhesion of Escherichia coli K12 and Bacillus sporothermodurans spores, in suspensions containing around 10 4 to 10 6 UFC/mL on stainless steel, at 37oC and adhesion time of 24 h and, iii) hygiene monitoring of truck surfaces, raw milk cooling tanks, pasteurizering tanks, milk centrifuge, pausterized milk storing tank and pausterized milk packaging tank. Aerobic mesophyllic and total coliform countings were also conducted in the water samples, respectively, expressed as UFC/mL and NMP/100 mL. The numbers of Aerobic mesophylls, expressed in UFC/cm 2 were determined on the surfaces. The UNILITEX-cel (Biotrace) luminometer was used for determining ATP, expressed as Relative Units of Light (RUL), including total and free ATP. For industrial water, there was an agreement between the bioluminescence and the counting methods of aerobic mesophylls and total coliforms Treatment and cooling water samples did not present any difference (p > 0.05) by the Tukey test for total and free ATP amounts nor for the microbial countings. Different microbial ATP concentrations were found for these water samples. The results indicate that the total ATP test is more adequate, suggesting that the physical chemical quality of water decreases light measurement. Bioluminescence was not appropriate to evaluate the presence of B. sporothermodurans and E. coli spores on the surfaces evaluated. RUL determination was affected by E. coli adhesion conditions. The results show that both total ATP and aerobic mesophyll countings were different (p < 0.05) when hygiene monitoring was compared before - 9772 RUL and 1.20 x 10 3 UFC/cm 2 - and after - 2511 RUL and 1.10 x 10 1 UFC/cm 2 . Biolominescence considered 100% of the surfaces to be under inadequate hygiene conditions while plate counting detected only 50%, based on APHA recommendation and 28%, based on WHO recommendation. There was no agreement between bioluminescence and microbial counting for hygiene condition classification under different surfaces. A great variation in RUL reading was observed, suggesting the need to carry out more than just one analysis on the surface evaluated. / Dissertação importada do Alexandria

magister en fisiología / El transportador ATP Binding Cassette A1 (ABCA1) facilita el flujo de salida de colesterol hacia las apolipoproteinas A-1 (apoA-1) libre de lípidos, siendo una proteína de membrana esencial en las etapas iniciales de la biogénesis de las lipoproteínas de alta densidad (HDL, High Density Lipoprotein, de sus siglas en inglés). Evidencia reciente sugiere que ABCA1 regula el contenido lipídico, la tolerancia a la glucosa y la sensibilidad a la insulina en el tejido adiposo. La mayor parte del transporte de glucosa mediado por GLUT4 ocurre en los túbulos transversales (TT), un sistema de membrana especializado enriquecido en colesterol y esfingolípidos presente en las células del músculo esquelético. De manera interesante, el contenido de colesterol en los TT está aumentado en ratones con resistencia a la insulina (RI). Sin embargo, aún es desconocido el papel de ABCA1 en el metabolismo de la glucosa del músculo esquelético. El objetivo principal de este trabajo fue evaluar el papel funcional del transportador ABCA1 sobre la homeostasis de la glucosa y la acumulación de colesterol en el músculo esquelético. Ratones C57BL/6J fueron alimentados por 8 semanas con una dieta control (NCD, Normal Chow Diet, de sus siglas en inglés) o una dieta alta en grasas (HFD, High Fat Diet, de sus siglas en inglés). Se realizaron ensayos de qPCR y Western blot sobre homogeneizados del músculo completo e inmunofluorescencia en fibras aisladas de músculo. Los ratones alimentados con NCD fueron electroporados con plasmidios shABCA1-RFP o scrambled y posteriormente se evaluó la vía de señalización dependiente de insulina, la captación de glucosa medida por 2-NBDG y el contenido de colesterol con la tinción de Filipina III en fibras aisladas del músculo flexor digitorum brevis (FDB). Los niveles de ARNm y el contenido de ABCA1 fue menor en los homogeneizados de músculo de ratones alimentados con HFD comparado con los ratones alimentados con NCD. ABCA1 fue localizado en los TT de fibras aisladas de FDB y la inmunotinción fue menor en fibras provenientes de músculos de ratones HFD comparados con los NCD. La electroporación in vivo del plasmidio shABCA1-RFP de los músculos FDB de ratones NCD resultó en una disminución del 70% del contenido de la proteína ABCA1, con un aumento de 1,6 veces el contenido de colesterol y una disminución de la fosforilación de Akt y de la captación de 2-NBDG dependiente de insulina, comparada con las fibras electroporadas con el plasmidio scrambled-RFP. Basado en estos resultados concluimos que ABCA1 regula el contenido de colesterol y afecta la captación de glucosa en fibras aisladas de músculo esquelético. La evidencia presentada en este trabajo, podría ayudarnos a definir si los cambios en la expresión/función de ABCA1 contribuye a la acumulación anómala de colesterol y el transporte alterado de glucosa, observado en las membranas de los TT del músculo esquelético en una condición de RI.

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京都大学 / 0048 / 新制・課程博士 / 博士(生命科学) / 甲第18430号 / 生博第310号 / 新制||生||41(附属図書館) / 31288 / 京都大学大学院生命科学研究科高次生命科学専攻 / (主査)教授 垣塚 彰, 教授 石川 冬木, 教授 松田 道行 / 学位規則第4条第1項該当 / Doctor of Philosophy in Life Sciences / Kyoto University / DFAM

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