Homocysteine (Hcy) has been identified as a primary risk factor for atherosclerosis as it induces endothelial cell (EC) activation/dysfunction and thus potentially initiating atherosclerotic plaque formation. There is accumulating evidence indicating a key role for oxidative stress in mediating Hcy atherogenic effects. The aim of this study was to evaluate the effects of chronic treatment with Hcy on EC activation and to explore the role of oxidative stress in these effects. Human umbilical vein endothelial cells (HUVEC) were cultured and treated chronically with DL-Hcy for 5-9 days. An in vitro flow system was also used to characterize the different types of interactions between DL-Hcy-treated HUVEC and neutrophils under physiological flow conditions. EC activation was studied by characterizing the activation of the JNK pathway and the up-regulation of different cell adhesion molecules (CAM) and cytokines, using different techniques including western blot, immunohistochemical staining, enzyme-linked immunosorbent assay and polymerase chain reaction. The role of oxidative stress was investigated by measuring the production of ROS and evaluating the efficiency of antioxidants. Furthermore, the role of nitric oxide and nitric oxide synthase in modulating Hcy effects was investigated. Chronic treatment with DL-Hcy did not kill the EC however, it inhibited cell proliferation. Furthermore, this treatment induced EC activation/dysfunction which was characterized by sustained activation of the JNK pathway, which in turn mediated up-regulation of E-selectin, ICAM-1 and to lesser extent P-selectin. Furthermore, DL-Hcy induced production of IL-8 protein. These CAM and chemokines collectively mediated different interactions between DL-Hcy-treated HUVEC and neutrophils under flow conditions including tethering, rolling, adherence and transmigration. DL-Hcy was also shown to induce significant ROS generation which mediated activation of the JNK pathway. Antioxidants restored DL-Hcy-induced interactions under flow to the basal level. DL-Hcy was shown to induce eNOS uncoupling which mediated, at least in part, the DL-Hcy-induced ROS production. Furthermore, short term treatment with NO inhibited DL-Hcy-induced HUVEC:neutrophil interactions in a cGMP-independent manner. In summary, this research showed that DL-Hcy has several proatherogenic effects, mediated at least in part by the JNK pathway, and induces EC activation/dysfunction priming for atherosclerosis initiation. The data supports that oxidative stress mediates the majority of Hcy atherosclerotic effects. Antioxidants tested, JNK inhibitors and NO showed promising results in reversing all DL-Hcy effects and restoring EC normal status.

論文(碩士)--香港中文大學, 1968. / Ms. / Includes bibliographical references (p.1-13 (4th group)). / Thesis (M.A.)--Xianggang Zhong wen da xue. / 緒言 / Chapter 上　編　 --- 丁日昌之政治、軍事及外交之經歷 / Chapter （一） --- 丁日昌之出身 / Chapter （二） --- 丁日昌在政治上之新作風及其改革意見 / Chapter （三） --- 丁日昌之軍事經歷 / Chapter （甲） --- 隨剿吉安太平軍 / Chapter （乙） --- 調和高州將帥意見肅清積年匪患 / Chapter （丙） --- 淮軍營務委員交涉解散常勝軍 / Chapter （丁） --- 海製造軍火，安定上海秩序及收回國家主權 / Chapter （四） --- 丁日昌在外交事務上之成就´ؤ圓滿解決潮州入城事件 / Chapter （甲） --- 潮州入城事件辦理失敗之原因及其經過 / Chapter （乙） --- 丁日昌解決潮洲入城事件之態度和方法 / Chapter 下　編 --- 丁日昌對中國陸軍近代化之嘗試 / Chapter （一） --- 丁日昌嘗試改變營制之原因 / Chapter （二） --- 丁日昌嘗試改變營制之方法 / Chapter （甲） --- 官軍(綠營)營制之基本缺點 / Chapter （乙） --- 勇營制度之優點 / Chapter （三） --- 丁日昌以前引用勇營營制改變官軍(綠營)營制失敗之原因 / Chapter （四） --- 丁日昌對中國陸軍近代化之新猷 / Chapter （甲） --- 調整江蘇省撫標營編制 / Chapter （乙） --- 以勇補兵´ؤ廢除舊有的兵籍制度 / Chapter （1） --- 以散勇之精銳補額兵之意義及其價值 / Chapter （2） --- 丁日昌防止約束勇丁滋事的辦法 / Chapter （丙） --- 提高將弁素質´ؤ改變武舉制度確立近代化陸軍的幹部政策 / Chapter （丁） --- 撤消營兵駐防汎地：建立正式國防軍及地方自衛保安武力 / Chapter （戊） --- 寓訓練於教育：軍隊學校化 / 結論 / 參考書目

by Chau Ho Wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 134-140). / Abstract also in Chinese. / ACKNOWLEDGMENTS --- p.iv / LIST OF TABLES --- p.v / ABBREVIATIONS --- p.vi / CHAPTER / Chapter ONE --- INTRODUCTION --- p.1 / Chapter 1.1 --- The Question: How the civil-military relations evolved during the post-Deng era? / Chapter 1.2 --- The Case of the 1996 Taiwan Straits Crisis / Chapter 1.3 --- Framework: Allison's Model of Decision-Making / Chapter 1.4 --- Data and Organization / Chapter TWO --- LITERATURE REVIEW --- p.11 / Chapter 2.1 --- Non-Communist Regimes / Chapter 2.2 --- Communist Regimes / Chapter 2.3 --- Post-Communist World / Chapter 2.4 --- Military Politics in China / Chapter THREE --- INSTITUTIONAL DEVELOPMENT OF PLA: FROM DENG TO POST-DENG ERA --- p.34 / Chapter 3.1 --- PLA in the Deng Era / Chapter 3.2 --- PLA in the Post-Deng Era / Chapter 3.3 --- "Professionalization, Differentiation and Institutionalization" / Chapter FOUR --- ORGANIZATIONAL INTERESTS OF PLA IN THE TAIWAN STRAITS CRISIS --- p.64 / Chapter 4.1 --- The War Games and the Policy Handle / Chapter 4.2 --- Employing the Organizational Process Model / Chapter 4.3 --- Organizational Interests and Demands of the PLA / Chapter 4.4 --- Information Processing of the PLA / Chapter 4.5 --- Resource Acquisitions of the PLA / Chapter FIVE --- BRINGING THE PLA INTERESTS INTO GOVERNMENTAL POLITICS --- p.100 / Chapter 5.1 --- Employing the Governmental Politics Model / Chapter 5.2 --- Perspectives of Jiang Zemin and PLA on the Taiwan Question / Chapter 5.3 --- Political Pulls and Hauls in the Taiwan Straits Crisis / Chapter 5.4 --- Legitimacy and Leadership Succession / Chapter SIX --- CONCLUSION --- p.126 / Chapter 6.1 --- Summary of Findings / Chapter 6.2 --- Prospects of Future Research / BIBLIOGRAPHY --- p.134

To explore the potential mechanisms of tendon degeneration, we investigated the role of c-Jun N-terminal Kinase (JNK) activation and the regulation of matrix metalloproteinase 1 (MMP1) in tendon matrix degradation under oxidative stress. JNK and MMP1 activity in samples from normal and ruptured human supraspinatus tendons were evaluated by immunohistochemistry. Real-time quantitative PCR was utilized to evaluate MMP1 mRNA expression and western blotting for MMP1 and JNK protein detection. JNK activation and increased MMP1 activity were found in the torn human supraspinatus tendon tissue, as well as in human tendon cells under in vitro oxidative stress. Inhibition of JNK prevented MMP1 over-expression in oxidative stressed human tendon cells. Results from the current study indicated that stress activated JNK plays an important role in tendon matrix degradation, possibly through upregulating of MMP1.

Successful axon regeneration appears to depend on the development of an injury response. Dorsal root ganglion neurons exemplify the necessity of this injury response in a unique way. Peripheral nerve transection leads to development of an injury response and successful regeneration whereas central root transection does neither. The injury response may involve extracellular and intracellular pathways. To investigate the extraneuronal influences, we performed nerve transection of either the central or peripheral axon branches and studied the expression of GAP-43, a key growth associated protein, and the transcription factors ATF3, c-Jun, and STAT3. Our results show that the responses to peripheral versus central nerve transection are fundamentally different. Peripheral but not central nerve transection increases GAP-43, ATF3, and c-Jun expression. STAT3, however, is upregulated as a result of central but not peripheral nerve transection. To investigate potential intracellular signalling pathways, we applied FGF-2, an extracellular mitogen, or an analog of cAMP, an intracellular second messenger to the cut end of the peripheral axon. Our results indicate that FGF-2 and cAMP act as activators of GAP-43 expression. On the other hand, FGF-2 and cAMP act to downregulate the expression of ATF3. FGF-2 upregulates c-Jun and the activated form of STAT3. Paradoxically, the regulation of GAP-43 expression by cAMP or by FGF-2 in vivo shows opposing results from the previously reported in vitro studies. Our present results suggest that the peripheral nerve injury response may be governed by at least three different signalling pathways.

Successful axon regeneration appears to depend on the development of an injury response. Dorsal root ganglion neurons exemplify the necessity of this injury response in a unique way. Peripheral nerve transection leads to development of an injury response and successful regeneration whereas central root transection does neither. The injury response may involve extracellular and intracellular pathways. To investigate the extraneuronal influences, we performed nerve transection of either the central or peripheral axon branches and studied the expression of GAP-43, a key growth associated protein, and the transcription factors ATF3, c-Jun, and STAT3. Our results show that the responses to peripheral versus central nerve transection are fundamentally different. Peripheral but not central nerve transection increases GAP-43, ATF3, and c-Jun expression. STAT3, however, is upregulated as a result of central but not peripheral nerve transection. To investigate potential intracellular signalling pathways, we applied FGF-2, an extracellular mitogen, or an analog of cAMP, an intracellular second messenger to the cut end of the peripheral axon. Our results indicate that FGF-2 and cAMP act as activators of GAP-43 expression. On the other hand, FGF-2 and cAMP act to downregulate the expression of ATF3. FGF-2 upregulates c-Jun and the activated form of STAT3. Paradoxically, the regulation of GAP-43 expression by cAMP or by FGF-2 in vivo shows opposing results from the previously reported in vitro studies. Our present results suggest that the peripheral nerve injury response may be governed by at least three different signalling pathways.

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The survival of several neuron populations during development, including sympathetic neurons, is strictly regulated by neurotrophins such as nerve growth factor (NGF) released from innervation targets. NGF activates its receptor, TrkA, at axon terminals, to generate signals that are transmitted retrogradely to cell bodies to induce signaling cascades regulating survival. A general view of this process is that NGF generates retrograde survival signals that, when delivered to cell bodies, induce downstream survival signaling that prevents apoptosis. A retrograde survival signal proposed to be necessary for sympathetic neuron survival consists of endosomes containing NGF and phosphorylated TrkA. For this signal, phosphorylated TrkA arriving at cell bodies is required to initiate survival signaling. Studies have tested the necessity of TrkA phosphorylation in the cell bodies for survival: results from different studies contradict each other. Moreover, the Trk inhibitor, K252a, used in these studies, has reported non-specific effects. Using an alternate Trk inhibitor, Gö6976, data presented in this thesis demonstrates that NGF can promote survival by retrograde signaling that does not require TrkA phosphorylation in the cell bodies. These retrograde signals may be composed of signaling molecules activated downstream of TrkA in axons since pro-survival molecules downstream of TrkA, Akt and CREB, were found activated in the cell bodies/proximal axons. Data presented in this thesis also reveals a fundamentally different mechanism for how NGF promotes sympathetic neuron survival: a retrograde apoptotic signal that is suppressed by NGF. NGF withdrawal from axons induced the “axon apoptotic signal” that was retrogradely transmitted to cell bodies to activate a key pro-apoptotic molecule, c-jun. The axon apoptotic signal, which was blocked by the kinase inhibitors rottlerin and chelerythrine, was necessary for apoptosis in response to NGF deprivation. Evidence GSK3 is involved in generation or transmission of the axon apoptotic signal was provided by experiments with GSK3 inhibitors and siRNA. The axon apoptotic signal discovery refutes the previous view that NGF acting on axon terminals supports survival exclusively by generating retrograde survival signals. The axon apoptotic signal has broad implications for understanding nervous system development and other conditions where neuronal apoptosis occurs, such as neurotrauma and neurodegenerative diseases.

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