INTRODUÇÃO: A isquemia cerebral é uma das principais causas de morte no Brasil, segundo levantamento da Sociedade Brasileira de Neurologia em 2000, sendo a terceira causa de morte após doenças cardiovasculares e o câncer, além de ser uma das maiores causas de sequela permanente capaz de gerar incapacidade. Nas últimas décadas, estudos experimentais tem demonstrado efeitos benéficos do exercício físico associado à isquemia cerebral. Vários mecanismos moleculares estão envolvidos na fisiopatologia da isquemia cerebral, entre eles as alterações nos perfis de expressão de neurotransmissores. Pesquisas atuais também destacam o papel dos microRNAs na isquemia cerebral quanto na regulação dos neurotransmissores. Portanto, analisar a expressão de neurotransmissores e microRNAs associados à isquemia cerebral, assim como o papel dos benefícios promovidos pelo exercício físico poderá contribuir na elucidação de possíveis vias moleculares com efeito neuroprotetor. MATERIAIS E MÉTODOS: Foram utilizados 48 animais divididos em quatro grupos experimentais: controle, submetido à isquemia cerebral, submetido ao exercício físico e submetido ao exercício físico associado à isquemia cerebral. A metodologia de PCR em tempo real foi utilizada para analisar a expressão dos miRNAs; miR15b, miR29b, miR-219 e miR-222. RESULTADOS E CONCLUSÃO: não observamos diferenças estatísticas significativas na expressão dos miRNAs miR-15b, miR- 12 29b, miR-219 e miR-222 no tecido cerebral dos grupos submetidos à isquemia cerebral, submetidos ao exercício físico e na associação dos dois grupos quando comparados ao grupo controle. Entretanto, os miRNAs miR-15b e miR222 apresentaram maior expressão no grupo com a associação da isquemia cerebral e exercício físico / INTRODUCTION: Cerebral ischemia is one of the main causes of death in Brazil, according to a survey by the Brazilian Society of Neurology in 2000, being the third cause of death after cardiovascular diseases and cancer, besides being one of the major causes of permanent sequela capable of generate disability. In the last decades, experimental studies have shown beneficial effects of physical exercise associated with cerebral ischemia. Several molecular mechanisms are involved in the pathophysiology of cerebral ischemia, including changes in neurotransmitter expression profiles. Current research also highlights the role of microRNAs both in the process of cerebral ischemia and in the regulation of neurotransmitters. Therefore, analyzing the expression of neurotransmitters and microRNAs associated with cerebral ischemia, as well as the role of the benefits promoted by physical exercise may contribute to the elucidation of possible molecular pathways with neuroprotective effect. MATERIALS AND METHODS: 48 animals were divided into 4 experimental groups: control, cerebral ischemia, physical exercise and physical exercise associated with cerebral ischemia. The real-time PCR methodology was used to analyze miRNA expression: miR15b, miR-29b, miR219 and miR-222. RESULTS AND CONCLUSION: We did not observe statistically significant differences in the miRNA expression of miRNAs: miR 15b, miR-29b, miR-219 and miR-222 in brain tissue groups submitted to 15 cerebral ischemia, physical exercise and in the association of the two groups when compared to the group control. However, the miR-15b and miR-222 levels of expression increased in the group of cerebral ischemia associated with physical exercise

Lin, Wenhua. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 162-190). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Lam, Ming Yiu. / "September 2011." / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 149-169). / Abstracts in English and Chinese. / Thesis / Assessment Committee --- p.ii / Abstract (English) --- p.iii / Abstract (Chinese) --- p.vi / Acknowledgements --- p.viii / Table of contents --- p.x / List of figures --- p.xvi / List of tables --- p.xix / Abbreviations --- p.xx / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Cerebral stroke --- p.1 / Chapter 1.2 --- Epidemiology --- p.2 / Chapter 1.3 --- Risk factors and symptoms --- p.5 / Chapter 1.3.1 --- Non-modifiable risks --- p.5 / Chapter 1.3.2 --- Modifiable risks --- p.6 / Chapter 1.3.3 --- Symptoms --- p.9 / Chapter 1.4 --- Mechanisms of cell injury --- p.10 / Chapter 1.4.1 --- Energy failure and loss of ionic homeostasis --- p.10 / Chapter 1.4.2 --- Excitotoxicity and calcium-modulated cell damage --- p.11 / Chapter 1.4.3 --- Oxidative stress --- p.13 / Chapter 1.4.4 --- Inflammation --- p.16 / Chapter 1.4.5 --- Apoptosis --- p.18 / Chapter 1.5 --- Current treatment of ischemia --- p.19 / Chapter 1.6 --- Chinese herbal medicine --- p.21 / Chapter 1.6.1 --- Traditional Chinese medicine theory on stroke --- p.21 / Chapter 1.6.2 --- Danshen --- p.22 / Chapter 1.6.3 --- Gegen --- p.25 / Chapter 1.6.4 --- Danshen-Gegen formula --- p.28 / Chapter 1.7 --- Aim of study --- p.30 / Chapter Chapter 2 --- General methodology --- p.31 / Chapter 2.1 --- Induction of transient focal cerebral ischemia by middle cerebral artery occlusion (MCAO) --- p.31 / Chapter 2.1.1 --- Intraluminal filament production --- p.32 / Chapter 2.1.2 --- Cerebral blood flow measurement by laser Doppler flowmetry --- p.33 / Chapter 2.1.3 --- Middle cerebral artery occlusion --- p.35 / Chapter 2.2 --- Neurological scoring --- p.38 / Chapter 2.3 --- Brain infarction measurement by triphenyltetrazolium chloride (TTC) staining --- p.40 / Chapter 2.4 --- Statistical analyses --- p.42 / Chapter Chapter 3 --- Preparation of herbal medicine --- p.43 / Chapter 3.1 --- Authentication of Chinese herbs --- p.43 / Chapter 3.1.1 --- Morphological authentication --- p.43 / Chapter 3.1.2 --- Chemical authentication using thin layer chromatography --- p.44 / Chapter 3.1.2.1 --- Danshen --- p.44 / Chapter 3.1.2.2 --- Gegen --- p.48 / Chapter 3.2 --- Danshen-Gegen (DG) extract preparation --- p.50 / Chapter 3.3 --- Chemical analysis of DG extract --- p.51 / Chapter 3.3.1 --- TLC --- p.51 / Chapter 3.3.2 --- HPLC --- p.54 / Chapter 3.4 --- Conclusion --- p.57 / Chapter Chapter 4 --- Protective effect of DG extract on cerebral ischemia --- p.58 / Chapter 4.1 --- Introduction --- p.58 / Chapter 4.1.1 --- Different models of ischemia --- p.58 / Chapter 4.1.2 --- Anti-oxidative enzymes in cerebral ischemia --- p.61 / Chapter 4.1.2.1 --- Superoxide dismutase (SOD) --- p.61 / Chapter 4.1.2.2 --- Catalase --- p.62 / Chapter 4.1.2.3 --- Glutathione peroxidase (GPX) --- p.62 / Chapter 4.2 --- Materials and methods --- p.64 / Chapter 4.2.1 --- "DG extract treatment, neurological deficit and brain infarction" --- p.64 / Chapter 4.2.2 --- Anti-oxidative enzymes activity determination --- p.65 / Chapter 4.2.2.1 --- Treatment with DG extract and induction of cerebral ischemia --- p.65 / Chapter 4.2.2.2 --- Extraction of enzymes from the brain --- p.66 / Chapter 4.2.2.3 --- Determination of protein concentration --- p.66 / Chapter 4.2.2.4 --- Assay kits --- p.67 / Chapter 4.3 --- Results --- p.70 / Chapter 4.4 --- Discussion --- p.80 / Chapter 4.4.1 --- Neurological score and percentage brain infarction --- p.80 / Chapter 4.4.2 --- Anti-oxidative enzyme induction --- p.82 / Chapter Chapter 5 --- Behavioral assessment using the shuttle box avoidance test on rats suffering from cerebral ischemia: effect of DG extract treatment --- p.86 / Chapter 5.1 --- Introduction --- p.86 / Chapter 5.1.1 --- Behavioral tests --- p.86 / Chapter 5.1.2 --- Theory of the test --- p.90 / Chapter 5.2 --- Materials and methods --- p.91 / Chapter 5.2.1 --- DG extract treatment --- p.91 / Chapter 5.2.2 --- Shuttle box training and MCAO --- p.92 / Chapter 5.2.3 --- Shuttle box testing --- p.96 / Chapter 5.2.4 --- Neurological score and brain infarction --- p.96 / Chapter 5.3 --- Results --- p.97 / Chapter 5.3.1 --- Shuttle box performance --- p.97 / Chapter 5.3.2 --- Neurological score --- p.105 / Chapter 5.3.3 --- Brain infarction --- p.109 / Chapter 5.4 --- Discussion --- p.112 / Chapter 5.4.1 --- The shuttle box protocol --- p.112 / Chapter 5.4.2 --- Shuttle box performance --- p.114 / Chapter 5.4.2.1 --- Pretreatment groups --- p.114 / Chapter 5.4.2.2 --- Pre + post treatment groups --- p.115 / Chapter 5.4.2.3 --- Comparison of pretreatment and pre + post treatment groups --- p.116 / Chapter 5.4.3 --- Neurological score --- p.117 / Chapter 5.4.4 --- Brain infarction --- p.118 / Chapter 5.4.5 --- Conclusion --- p.119 / Chapter Chapter 6 --- Anti-blood coagulation effect of DG extract --- p.121 / Chapter 6.1 --- Introduction --- p.121 / Chapter 6.2 --- Materials and methods --- p.125 / Chapter 6.2.1 --- Treatment with DG extract and warfarin --- p.125 / Chapter 6.2.2 --- Tail bleeding time and volume --- p.126 / Chapter 6.2.3 --- Prothrombin time --- p.127 / Chapter 6.2.4 --- Platelet aggregation --- p.127 / Chapter 6.3 --- Results --- p.128 / Chapter 6.4 --- Discussion --- p.138 / Chapter Chapter 7 --- General discussion --- p.141 / Chapter 7.1 --- General discussion and conclusion --- p.141 / Chapter 7.2 --- Clinical significance of the study --- p.145 / Chapter 7.3 --- Limitations of the study --- p.146 / Chapter 7.4 --- Future work --- p.147 / References --- p.149 / Publications --- p.170

Thesis (M.Sc.)--Memorial University of Newfoundland, 2005. / Bibliography: leaves 31-42.

The peripheral immune system plays a role in delayed neural injury after stroke. This response originates from the spleen as splenectomy prior to middle cerebral artery occlusion (MCAO) in rats significantly reduces infarct volume in the brain. This research is based on the hypothesis that inhibiting the splenic response will reduce neurodegeneration after stroke. Studies in animals have implicated lymphocytes as the immune cell type that is detrimental following MCAO. Interferon gamma (IFNγ) has been identified as a pro-inflammatory cytokine that is also detrimental following stroke. IFNγ is important because it activates microglia and macrophages in a pro-inflammatory nature that increases neural injury following stroke. Therefore IFNγ was examined in the brain and the spleen following MCAO. IFNγ protein was elevated at 24 h in the spleen and at 72 h in the brain post MCAO. Microglia/macrophages become maximally activated at 72 h in the brain after MCAO. Splenectomy decreases the levels of IFNγ in the brain following MCAO. Systemic administration of IFNγ reversed the protective effects of splenectomy. The cellular response to MCAO was examined next because of the difference in time between the spike in IFNγ in the spleen and the delayed increase in the brain. The cellular response from the spleen was studied by labeling splenocytes five days prior to MCAO with a fluorescein dye. Tissues were examined 48 and 96 h post MCAO or sham MCAO for fluorescence. These cells were released from the spleen into circulation at 48 h post MCAO and migrated to the brain where the cells produced IFNγ at 96 h post MCAO. IFNγ appears to play a role in the splenic response to stroke. One protein that is up regulated by cells that have been activated by IFNγ, interferon-inducible protein 10 (IP-10) is part of the inflammatory cycle driven by IFNγ. IP-10 recruits more IFNγ producing T helper (Th) cells to the site of injury. IP-10 has the unique ability to attract Th1 cells, the pro-inflammatory Th cells, and inhibit Th2 cells, the anti-inflammatory Th cells. This leads to more IFNγ production as IFNγ is the signature cytokine of a Th1 response. IP-10 is significantly increased in the brain at 72 h post MCAO, similar to IFNγ expression. In the spleen IP-10 increased at 24 h and remained elevated out to 96 h following MCAO. IFNγ signaling was inhibited by utilizing an IFNγ neutralizing antibody administered beginning 24 h post MCAO. The IFNγ antibody treated group had decreased infarct volumes, IP-10 levels in the brain, and appeared to have decreased T cells in the ipsilateral hemisphere at 96 h post MCAO. Following ischemic stroke splenocytes are released into circulation and migrate to the brain. They release IFNγ to activate microglia/macrophages in a proinflammatory phenotype causing an increase in IP-10 levels. IP-10 then potentiates the Th1 driven inflammation which inhibits the Th2 response. The elevated levels of IFNγ increase neural injury following MCAO. Blocking IFNγ selectively blocks the inflammatory facet of the immune response to reduce stroke induced neurodegeneration. This leaves the other immune responses intact and able to contribute to tissue repair, regeneration, and able to respond to infections. Selectively inhibiting IFNγ signaling is a promising stroke therapeutic.

The overarching aim of the thesis research was to investigate mechanisms altered by protein-energy malnutrition (PEM), a common stroke co-morbidity factor that could affect the extent of brain damage and recovery following stroke. To model stroke, the rat 2-vessel occlusion model of global brain ischemia was employed. To characterize the effects of PEM, three states of malnutrition were assessed: PEM co-existing with brain ischemia (Study 1), effects of PEM independent of brain ischemia (Study 2), and PEM developing after brain ischemia (Study 3). The first hypothesis tested was co-existing PEM triggers an exacerbated glial response to global brain ischemia. The failure to achieve a consistent model of global ischemia prevented us from drawing conclusions on whether co-existing PEM exacerbates reactive gliosis. Nonetheless, this study demonstrated that mean temperature and temperature fluctuation are increased within the first 24hr of exposure to a low protein diet. The second hypothesis tested was PEM causes sustained changes in core temperature that are associated with an inflammatory response. Exposure to a low protein diet caused an immediate small and transient increase in mean temperature and a larger sustained increase in temperature amplitude. As malnutrition evolved, mean temperature declined. PEM stimulated an acute-phase response, characterized by an increase in the positive acute-phase protein, alpha-2-macroglobulin (A2M), and a decrease in the negative acute-phase protein, albumin. This response appeared to be aberrant, since the positive acute-phase protein, alpha-1-acid glycoprotein (AGP), was decreased with PEM. The final hypothesis tested was PEM developing after global brain ischemia exacerbates systemic and hippocampal inflammation, which is associated with diminished neuroplasticity. The effects of PEM on the acute-phase response are persistent following brain ischemia, as demonstrated by decreased serum albumin and increased serum A2M. A decrease in the positive acute-phase protein, haptoglobin, strengthened the evidence that PEM triggers an atypical reaction. The strong glial response elicited by global ischemia was unaltered by PEM. However, PEM influenced hippocampal neuroplasticity mechanisms, as GAP-43 and synaptophysin were significantly lower at d21. In summary, it has been demonstrated that PEM affects core temperature, the systemic acute-phase reaction and the neuroplasticity response to global brain ischemia.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 5 uppsatser.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2006. / Härtill 5 uppsatser.

Thesis (doctoral)--Lund University, 1998. / Added t.p. with thesis statement inserted.