Pan, Tak Yin. / Thesis submitted in: November 2007. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references. / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract (English) --- p.ii / Abstract (Chinese) --- p.iv / Content --- p.v / Abbreviations --- p.x / List of Figures --- p.xi / List of Tables --- p.xii / Chapter Chapter 1: --- Introduction --- p.1 / Chapter 1.1 --- Alzheimer's Disease --- p.1 / Chapter 1.1.1 --- Cholinergic hypothesis --- p.2 / Chapter 1.1.2 --- p-amyloid hypothesis --- p.2 / Chapter 1.1.3 --- Taupathy hypothesis --- p.3 / Chapter 1.1.4 --- Current therapies --- p.4 / Chapter 1.2 --- Proteins Involved in Alzhemer's Disease --- p.5 / Chapter 1.2.1 --- Acetylcholinesterase (AChE) --- p.5 / Chapter 1.2.2 --- p-amyloid --- p.6 / Chapter 1.2.3 --- Paired helical filaments (PHF) --- p.7 / Chapter 1.2.4 --- Protein kinases --- p.8 / Chapter 1.2.4.1 --- Glycogen synthase kinase-3 (GSK-3) --- p.9 / Chapter 1.2.4.2 --- Cyclin-dependent kinase-5 (CDK-5) --- p.9 / Chapter 1.2.5 --- Protein phosphatase (PP) --- p.10 / Chapter 1.2.5.1 --- Protein phosphatase 1 (PP-1) --- p.11 / Chapter 1.2.5.2 --- Protein phosphatise 2A (PP-2A) --- p.12 / Chapter 1.2.5.3 --- Protein phosphatise 2B (PP-2B) --- p.13 / Chapter 1.2.6 --- Apoptotic and Anti-apoptotic proteins --- p.14 / Chapter 1.2.6.1 --- Caspase-3 --- p.15 / Chapter 1.2.6.2 --- Bcl-2 --- p.15 / Chapter 1.3 --- Flavonoids --- p.16 / Chapter 1.3.1 --- Biosynthesis of flavonoids --- p.17 / Chapter 1.3.2 --- Biological functions of flavonoids in plants --- p.18 / Chapter 1.3.3 --- Beneficial effects of flavonoids on human health --- p.19 / Chapter Chapter 2: --- Materials and Methods --- p.20 / Chapter 2.1 --- Differentiation of SHSY-5Y cells --- p.20 / Chapter 2.1.1 --- SHSY-5Y cell culture --- p.20 / Chapter 2.1.2 --- Counting cells --- p.20 / Chapter 2.1.3 --- Retinoic acid differentiation --- p.21 / Chapter 2.2 --- Western blot analysis --- p.21 / Chapter 2.2.1 --- Extraction of proteins from mammalian cells --- p.21 / Chapter 2.2.2 --- Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) --- p.22 / Chapter 2.2.3 --- Semi-dry protein transfer to nitrocellulose membrane --- p.23 / Chapter 2.2.4. --- Membrane blocking and immunostaining --- p.24 / Chapter 2.3 --- MTT assay --- p.25 / Chapter 2.4 --- Hoechst 33342 Nuclei staining --- p.25 / Chapter 2.5 --- Cell cycle analysis --- p.25 / Chapter 2.5.1 --- Ethanol fixation --- p.25 / Chapter 2.5.2 --- Propidium iodide staining --- p.26 / Chapter 2.6 --- Annexin V-FITC & Propidium iodide staining --- p.26 / Chapter 2.7 --- DNA fragmentation analysis --- p.26 / Chapter 2.7.1 --- Phenol/Chloroform extraction of DNA --- p.26 / Chapter 2.7.2 --- Ethanol precipitation of DNA --- p.27 / Chapter 2.7.3 --- Agarose gel electrophoresis of DNA --- p.27 / Chapter 2.8 --- Proteomic analysis --- p.28 / Chapter 2.8.1 --- First dimension: isoelectric focusing --- p.28 / Chapter 2.8.2 --- Second dimension: SDS PAGE --- p.29 / Chapter 2.8.3 --- Gel staining --- p.30 / Chapter 2.8.3.1 --- Silver staining --- p.30 / Chapter 2.8.3.2 --- SYBRO Ruby staining --- p.31 / Chapter 2.8.4 --- Gel scanning and image analysis --- p.31 / Chapter 2.8.5 --- ln-gel digestion --- p.32 / Chapter 2.8.6 --- Zip Tip for desalting the digested sample --- p.33 / Chapter 2.8.7 --- Protein identification with mass spectrometry and database search --- p.33 / Chapter Chapter 3: --- Characterization of Okadaic acid-induced tail hyperphosphorylation in SHSY-5Y cells --- p.35 / Chapter 3.1 --- Introduction --- p.35 / Chapter 3.2 --- Objectives --- p.37 / Chapter 3.3 --- Results --- p.38 / Chapter 3.3.1 --- Differentiation of SH-SY5Y cell --- p.38 / Chapter 3.3.2 --- Changes of protein expression after okadaic acid treatment --- p.40 / Chapter 3.3.3 --- Neurite Retraction Induced by okadaic acid --- p.42 / Chapter 3.3.4 --- Okadaic acid-induced Cell Death measured by MTT assay --- p.44 / Chapter 3.3.5 --- Hoechst 33342 Nuclei Staining --- p.44 / Chapter 3.3.6 --- Cell cycle analysis by propidium iodide staining --- p.47 / Chapter 3.3.7 --- Early Apoptotic cells detection by Annexin V/PI staini --- p.49 / Chapter 3.3.8 --- DNA fragmentation --- p.51 / Chapter 3.4 --- Discussion --- p.53 / Chapter Chapter 4: --- Flavonoids screening for protecting neuronal death by preventing tau hyperphosphorylation --- p.57 / Chapter 4.1 --- Introduction --- p.57 / Chapter 4.2 --- Objectives --- p.58 / Chapter 4.3 --- Tested flavonoids --- p.59 / Chapter 4.4 --- Results --- p.60 / Chapter 4.4.1 --- Toxicity of flavonoids --- p.60 / Chapter 4.4.2 --- Effects of flavonoid pre-treatment on OA-induced neu retractions and cell death --- p.62 / Chapter 4.4.3 --- Western blot analysis --- p.65 / Chapter 4.4.4 --- The effect of different concentrations of hesperidin or OA treatment --- p.70 / Chapter 4.4.5 --- Proteomic analysis --- p.74 / Chapter 4.5 --- Discussion --- p.78 / Chapter Chapter 5: --- General Discussion --- p.82 / References

Estudamos os achados da espectroscopia de prótons no córtex parietal-cíngulo posterior e das escalas MEEM, BRDS e FAST em pacientes com doença de Alzheimer - DA, comprometimento cognitivo amnéstico - CCA e controles normais - CN. Apenas as razões NAA/Cr e MI/NAA diferenciaram (p < 0.002) os grupos DA e CN. Houve correlação significativa do NAA/Cr e do MI/NAA com o BRDS (pontuação total - PT; atividades cotidianas - AC) e FAST, e do MI/NAA com o MEEM. Houve acréscimo de 5% na especificidade (CN x DA; CN x CCA), e de 2.4% (CN x DA) e 3.4% (CN x CCA) na acurácia diagnóstica, ao adicionar as razões NAA/Cr e MI/NAA às escalas BRDS (PT e AC) e FAST, aumentando a detecção de indivíduos com CCA e DA / We studied the findings of proton spectroscopy of the posterior parietal-cingulate cortex, and of MMSE, BRDS and FAST scales in subjects with Alzheimer disease - AD, amnestic mild cognitive impairment - MCI-A and normal controls - NC. Only NAA/Cr and MI/NAA differentiated (p < 0.002) the AD and NC groups. Significant correlation was found between NAA/Cr and MI/NAA with BRDS (total score - TS; everyday activities - EA) and FAST scales, and between MI/NAA and MMSE. Specificity increased in 5% (NC x AD; NC x MCI-A) and diagnostic accuracy in 2.4% (NC x AD) and 3.4% (NC x MCI-A) when NAA/Cr and MI/NAA ratios were added up to BRDS (TS & EA) and FAST scales, increasing MCI-A and AD detectability

Estudamos os achados da espectroscopia de prótons no córtex parietal-cíngulo posterior e das escalas MEEM, BRDS e FAST em pacientes com doença de Alzheimer - DA, comprometimento cognitivo amnéstico - CCA e controles normais - CN. Apenas as razões NAA/Cr e MI/NAA diferenciaram (p < 0.002) os grupos DA e CN. Houve correlação significativa do NAA/Cr e do MI/NAA com o BRDS (pontuação total - PT; atividades cotidianas - AC) e FAST, e do MI/NAA com o MEEM. Houve acréscimo de 5% na especificidade (CN x DA; CN x CCA), e de 2.4% (CN x DA) e 3.4% (CN x CCA) na acurácia diagnóstica, ao adicionar as razões NAA/Cr e MI/NAA às escalas BRDS (PT e AC) e FAST, aumentando a detecção de indivíduos com CCA e DA / We studied the findings of proton spectroscopy of the posterior parietal-cingulate cortex, and of MMSE, BRDS and FAST scales in subjects with Alzheimer disease - AD, amnestic mild cognitive impairment - MCI-A and normal controls - NC. Only NAA/Cr and MI/NAA differentiated (p < 0.002) the AD and NC groups. Significant correlation was found between NAA/Cr and MI/NAA with BRDS (total score - TS; everyday activities - EA) and FAST scales, and between MI/NAA and MMSE. Specificity increased in 5% (NC x AD; NC x MCI-A) and diagnostic accuracy in 2.4% (NC x AD) and 3.4% (NC x MCI-A) when NAA/Cr and MI/NAA ratios were added up to BRDS (TS & EA) and FAST scales, increasing MCI-A and AD detectability

Alzheimer's disease (AD) is the most common form of dementia. As the prevalence of AD increases with age, population aging will inevitably lead to an exponential increase in the proportion of older persons suffering from this disease. According to 2005 WHO estimate, 26.6 million people (approximately 0.55% of the general population) suffered from this disease. AD not only affects intellectual and functional abilities, it is also associated with significant neuropsychiatric disturbances. The pathogenesis of AD is characterized by widespread cerebral atrophy, abnormal deposition of amyloid plaques and tau protein in the central nervous system. While the classical histopathological features of AD are well recognized, exact physiological mechanisms that initiate the cascade of neural degeneration are still under active investigation. / As mentioned, the telomere length studies focused on ethically Chinese subjects recruited from two independent samples. The first clinical sample consisted of 411 older people and the other sample from healthy aging study, 976 community dwelling men were recruited. All subjects were assessed with the Cantonese version of the Mini-mental State Examination (CMMSE) for global cognitive function. Genomic DNA of the subjects was extracted from the peripheral whole blood sample. Lengths of the telomere were measured with Quantitative Real-Time PCR and the Ct ratio of the telomere and a control gene (36B4) of each sample was compared with the standard curve constructed with 4 selected sample's telomere lengths measured previously by Southern blotting. / For the first association study of the cell cycle checkpoint genes and AD, sample was recruited from a prospective study of cognitive function and risk factors for development of AD. 701 elderly were clinically evaluated for diagnosis of AD by psychiatrists. For this sample, genotyping of tagging SNPs of the 10 cell-cycle checkpoint genes were carried out by Restriction Fragment Length Polymorphism (RFLP) analysis. All tagging SNPs were selected from HapMap database and 5000bp upstream and downstream regions of each gene was also included. / For the results, the association study with cell cycle checkpoint genes, there was no SNPs found to be associated with diagnosis of clinical AD. We also found out that telomere length was associated with age in both two healthy aging men and clinical samples. There was no association between education and telomere lengths. For subjects in the healthy aging study, participants with CMMSE scores fell into the lowest 25% were found to have shorter telomere lengths. Similar result was found in the clinical AD sample. / In the study, telomere lengths were negatively associated with age. As the telomere will be shortened for each cell cycle, this finding correlated with physiological function at a cellular level. Statistical analysis also showed that shorter telomere lengths were found in subjects with poorer cognitive function. However, as age is a major determinant for cognitive impairments, further studies are recommended to evaluate the interaction effects of age in this association. Telomere shortening will cause cell senescence, and may be associated with faster neuronal degeneration, thus affecting cognitive function. Further studies should be conducted to examine its usefulness as an adjuvant biomarker for risk stratification of AD intervention trials. / Recent researches begin to unfold the physiological significance of telomere. A telomere is a repetitive region at the end of a chromosome. Basic functions of telomeres are involved with protection of the chromosome during replication and preventing chromosomal rearrangement or fusion. Abnormal telomere lengthening may be related to cancerous conditions. At a cellular level, telomere may also be related to aging and limitation in cell lifespan. In my study, I aimed to evaluate the association between the lengths of telomere and global cognitive function in community dwelling Chinese older persons in Hong Kong. As the length of telomere is also determined by the turnover rates of cells, apart from association study of telomere lengths and cognitive function, I also tried to study the association of genes related to cell cycles and AD. Polymorphisms of ten cell-cycle checkpoint genes, i.e. RB1, CDKN1A, CDK5R1, CDK2AP1, CDKN2A, CDKN2C, MDM2, P53, GSK3B, TPND1 and CDKN1B genes, were chosen in my project. / The thesis comprised of three studies. The first study was an association study of cell cycle checkpoint gene single nucleotide polymorphisms (SNPs) with clinical diagnosis of AD. The second study was an association study of telomere lengths and clinical diagnosis of AD in a clinical sample of patients suffering from the disease. The third study was an association study of the telomere lengths and global cognitive status in a group of active community dwelling older men who participated in a healthy aging study. / Lau, San Shing. / Adviser: Linda C.W. Lam. / Source: Dissertation Abstracts International, Volume: 73-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 101-124). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.