Thesis (MSc)--University of Stellenbosch, 2007. / ENGLISH ABSTRACT: Introduction Cardiovascular disease is one of the leading causes of death in the world. Formation of harmful reactive oxygen species (ROS) is associated with several pathological conditions, and contributes to ischaemia/reperfusion injury. Antioxidants can be added to the diet in an attempt to decrease the prevalence of cardiovascular disease by decreasing the harmful effects of ischaemia/reperfusion injury. Red Palm Oil (RPO) consists of saturated, monounsaturated and polyunsaturated fatty acids and is rich in antioxidants such as -carotene, tocopherols and tocotrienols. It has previously been shown that RPO-supplementation improved reperfusion mechanical function. In these studies it was found that RPO might exert its beneficial effects during reperfusion through increased PKB/Akt pathway activity, which may lead to inhibition of apoptosis and improved mechanical function. Aims The aims of this study were: 1) to determine whether RPO-supplementation protected against ischaemia/reperfusion injury in the isolated perfused rat heart, 2) to confirm RPO-supplementation’s effect on the PKB/Akt pathway activity and, 3) to elucidate the regulators in the PKB/Akt pathway that RPOsupplementation influenced. Methods Male Wistar rats were divided into 4 groups, 2 control groups and 2 experimental groups. The 2 control groups were fed a standard rat chow (SRC) for 4 weeks. The two experimental groups received SRC and RPOsupplementation for 4 weeks. Hearts were excised and transferred to a Langendorff perfusion apparatus and perfused with Krebs-Henseleit buffer. Mechanical functional recovery was measured after 25 min of total global noflow ischaemia. The following parameters were also measured during various time points in the protocol: left ventricular develop pressure, heart rate, coronary flow, rate pressure product. Hearts were also freeze-clamped for biochemical analysis at 10 min during reperfusion. The biochemical analysis was aimed at determining PKB/Akt involvement. In a second protocol, hearts were subjected to the same perfusion protocol, but wortmannin was also added to the perfusion fluid, in order to inhibit PI3- kinase. Results Hearts from the RPO-supplemented rats showed an improved RPP recovery (92.26 ± 5.89 % vs 63.86 ± 7.74 %) after 10 min of reperfusion. This finding corroborated the findings of previous studies. Hearts of the RPOsupplemented rats perfused with wortmannin, showed increased RPP recoveries at several time points. Biochemical results showed that wortmannin did indeed inhibit PI3-K phosphorylation in the RPO-supplemented group, as was expected. The RPO-supplemented group that was perfused with wortmannin had an increased PKB/Akt (Ser473) phosphoyrylation, when compared to the wortmannin control group. It was also found that the combination of RPO and wortmannin had prosurvival effects. Discussion This study showed that RPO-supplementation offered protection against ischaemia/reperfusion injury in the Langendorff-perfusion apparatus at 10 min into reperfusion. Thereafter the significance of the protection was lost. This protection has been confirmed in several previous studies and several mechanisms have been proposed for this protection. Since no conclusive evidence exists on the precise mechanism of protection, our investigation focused on the regulators of the pro-survival PKB/Akt pathway. An improved functional recovery was also seen in the RPO-supplemented group that was perfused with wortmannin. This was an unexpected finding, because Wortmannin is a known PI3-kinase inhibitor (as was confirmed by our biochemical data). PI3-kinase phosphorylation leads to PKB/Akt phosphorylation and therefore, activation of a pro-survival pathway. It would be expected that wortmannin would inhibit PKB/Akt and thus decrease the survival of the cells. The RPO-supplementation thus reversed wortmannin’s detrimental effect to such an extent that the functional recovery was far better than RPO-supplementation alone. In the RPO + wortmannin group, PKB/Akt (Ser473) phosphorylation was increased, contrary to previous findings. This is an indication that RPO may have the ability to override wortmannin’s inhibitory effect on PI3-kinase, or that PKB/Akt (Ser473) may be phosphorylated independently of PI3-kinase. / AFRIKAANSE OPSOMMING: Inleiding Kardiovaskulêre siektes is een van die hoof oorsake van sterftes in die wêreld. Die vorming van skadelike reaktiewe suurstof spesies word geassosieer met verskeie patologiese kondisies en dra ook by tot isgemie/reperfusie skade. ‘n Moontlike manier om die voorkoms van isgemie/herperfusie skade asook kardiovaskulêre siektes te voorkom, is om antioksidante by die dieet te voeg. Rooi Palm Olie (RPO) bevat versadigde, mono-onversadigde en polionversadigde vetsure. RPO bevat ook ‘n oorvloed van antioksidante soos β- karoteen en tokoferole en tokotriënole. Dit is bewys in vorige studies dat RPO-aanvulling verbeter funksionele herstel. Hierdie voordelige effekte mag dalk wees agv verhoogde PKB/Akt pad aktiwiteit. Die PKB/Akt pad word geassosieer met die inhibisie van apoptose en verhoogde meganiese funksie. Doelwitte Die doelwitte van hierdie studie was om te bepaal of 1) RPO-aanvulling beskermende effekte teen isgemie/herperfusie skade in die geisoleerde rotharte het, 2) Bevestig of RPO-aanvulling wel die PKB/Akt pad beïnvloed 3). om die effekte wat RPO-aanvulling het op die reguleerders van die PKB/Akt pad te onthul. Metodes Manlike Wistar rotte is in 4 groepe verdeel. 2 Groepe kontrole rotte is ‘n standaard rotkosmengsel gevoer vir 4 weke. Die 2 eksperimentele groepe het ook ‘n standaard rotkosmengsel gekry plus ‘n RPO-aanvulling vir 4 weke. Harte is uitgesny en op ‘n Langendorff perfusie sisteem gemonteer en met Krebs-Henseleit buffer geperfuseer. Meganiese funksie herstel is gemeet na 25 min totale globale geen-vloei isgemie. Linker ventrikulêre ontwikkelde druk, harttempo, koronêre vloei en tempo druk produk is gemeet by verskillende tydpunte. Sommige harte is na 10 min herperfusie vir biochemiese analiese gevriesklamp. Die biochemiese analisiese was beoog om die PKB/Akt pad betrokkenheid te bepaal. ‘n Tweede stel harte is aan dieselfde perfusie protokol blootgestel, maar wortmannin (PI3-kinase inhibitor) is ook bygevoeg by die perfusie vloeistof. Resultate Die groep wat met RPO aangevul is, het na 10 min herperfusie, ‘n verbeterde tempo druk produk herstel getoon (92.26 ± 5.89 % vs 63.86 ± 7.74. Hierdie bevinding is ook met ander studies bevestig. ‘n Interessante bevinding was dat die groep wat met RPO aangevul is en met wortmannin geperfuseer is, ‘n verbeterde meganiese funksionele herstel getoon het. Biochemiese resultate het getoon dat wortmannin wel PI3-K fosforilering geinhibeer het. Die harte van die rotte in die groep wat aangevul is met RPO en daarna met wortmannin geperfuseer is, het ‘n toename in PKB/Akt (Ser473) fosforilering getoon, relatief tot die wortmannin geperfuseerde harte van die rotte in die kontrole groep. Hierdie groep (RPO-aanvulling en wortmannin perfusie) het beskermende effekte getoon. Bespreking Hierdie studie het getoon dat RPO-aanvulling beskerming gebied het teen isgemie/herperfusie skade in die Langendorff geperfuseerde rothart na 10 min herperfusie. Daarna is die beduidenheid van die beskerming verloor. Hierdie bevindings ondersteun die resultate van vorige studies. Verskeie moontlike meganismes is voorgestel vir die beskerming, maar die presiese meganisme is nog nie duidelik nie. In hierdie studie is daar gekyk na die reguleerders van die PKB/Akt pad. Geen vorige studies het al gefokus op RPO-aanvulling en sy effek op die reguleerders van die PKB/Akt pad nie. ‘n Onverwagte bevinding is dat harte van die rotte in die RPO + wortmannin groep ‘n verbeterde funksionele herstel getoon het. Wortmannin is ‘n PI3- kinase inhibitor. PI3-K fosforilering lei tot PKB/Akt fosforilering, wat tot sel beskerming lei. Dus, aangesien wortmannin PI3-K inhibeer, sou dit verwag word dat wortmannin sel beskerming sal verminder. Die RPO het egter die wortmannin se nadelige effekte tot so ‘n mate oorskrei dat die funksionele herstel baie beter was as die RPO-aanvulling alleen. Die verhoogde PKB/Akt (Ser473) fosforilering, wat gesien is in die RPO + wortmannin groep kan toegeskryf word aan RPO se vermoë om wortmannin se nadelige effekte te oorskrei. ‘n Moontlike verduideliking vir hierdie bevinding mag wees dat rooi palm olie PKB/Akt (Ser473) op ‘n PI3-K onafhanklike manier fosforileer.

Thesis (PhD (Biomedical Sciences. Medical Physiology))--Stellenbosch University, 2008. / The overall objective of this thesis is to provide additional data to assist clinicians and experimental neurologists alike in the quest for better understanding, more accurately diagnosing and more successfully treating patients suffering from Parkinson’s disease (PD). The general theme of the thesis is the interaction between certain environmental stimuli, including the exposure to adverse events during early central nervous system (CNS) development and the manifestation of elements of neurodegeneration, whether by means of neurochemical changes or expressed as a dysfunctional voluntary motor system. The first chapter provides a general introduction to the research theme of the thesis. This includes, in particular, a discussion on current understanding concerning the etiology and clinical profile of PD, the relative contribution made by genetic factors compared to environmental ones, and current treatment strategies for treating the disease. Mention is also made of the failure of these therapeutic applications for reversing or protecting against the disease, due to the side-effects associated with them. The material covered in chapter 1 provides the basis for the more complete discussion concerning these various aspects, contained in the chapters to follow. The overall aim was also to characterise the effects of commonly used toxin-induced animal models of PD, and the extent of vulnerability that the CNS displays towards them. The destruction of dopaminergic neurons following the administration of 6-OHDA at targeted points along the nigrostriatal tract is used extensively to model PD pathology in rats and is an established animal model of the disease. However, mature or even aged animals are mainly used in these studies, while the effects that the toxin might have on the developing CNS remain unclear. The study reported in chapter 4 aimed to elucidate some of 6-OHDA’s actions on the young adolescent (35 days-old) CNS by comparing the motor and biochemical effects of a unilateral infusion of the toxin into two anatomically distinct basal ganglia loci: The medial forebrain bundle (MFB) and the striatum. Animals were randomly assigned to receive either a direct delivery of 6-OHDA (12μg/4μl) into the MFB or an indirect injection, into the striatum. Although both lesion types were used, the MFB model is considered a more accurate portrayal of end-stage PD, while the striatum-model better reflects the long-term progressive pathology of the disease. The different lesions’ effects on motor function were determined by observing animal’s asymmetrical forelimb use to correct for weigh shifting during the vertical exploration of a cylindrical enclosure. Following the final behavioral assessment, the concentration of dopamine (DA) and DA metabolites remaining in the post-mortem brains were determined using 4 HPLC electrochemistry (HPLC-EC) and the levels compared between the two groups. The HPLC-EC results revealed a compensatory effect for DA production and DA turnover on the lesioned hemisphere side of the toxin-infused animal group. Thus, following 6-OHDA treatment, there appears to be extensive adaptive mechanisms in place within the remaining dopaminergic terminals that may be sufficient for maintaining relatively high extracellular and synaptic concentrations of DA. However, since substantial changes in motor-function were observed, it is suggested that the capacity of the remaining dopaminergic neurons to respond to increased functional demands may be limited. In addition, the behavioral results indicate that the distinct indices relating to different functional deficits depend on the lesioning of anatomically distinct structures along the nigrostrial tract. It has long been known that far fewer women are diagnosed with PD than men are. This seeming protection offered to females against degenerative disease of the CNS may relate to estrogen, although the hormone’s mechanism of action on the dopaminergic system is poorly defined. With an estimated 10-15 million women using oral contraceptives (OCs) in the United States alone, the aim of chapter 2 was to examine the evidence for a possible relationship between PD and the female reproductive hormone estrogen. A review of the current literature available on the topic was performed by consulting Medline, and by performing a search of the case-reports contained within the World Health Organization’s (WHO) International Drug Monitoring database, for possible PD-related symptoms that may arise from estrogen replacement therapy (ERT). The results, whilst conflicting, seem to suggest that estrogen protects women from obtaining the disease, or at least some features of it. Intensive research efforts are called for, with sufficient power to establish the relationship between ERT and the onset and development of parkinsonism. Chapter 3 reports on the results obtained from an experiment that subjected young Sprague-Dawley rats, 35 days of age, to a lower and a higher dose of 6-OHDA delivered to the MFB. Control rats received equivalent saline infusions. At 14 days post-surgery, the rats were evaluated for forelimb akinesia. For the higher dose of 6- OHDA the female rats were less impaired than males in making adjustment steps in response to a weight shift and in the vibrissae-evoked forelimb placing test. In addition, Tyrosine hydroxylase (TH) immunoreactivity was significantly higher for the female rats. Early gender differences in cell survival factors and/or other promoters of neuroplasticity may have contributed to the beneficial outcome seen in the females. For example, nerve growth factor (NGF) was found to be higher in the female rats following administration of the DA neurotoxin. It is unclear whether gonadal steroids are involved, and, if so, whether female hormones are protective or whether male hormones are prodegenerative. Determining the mechanisms for the improved outcome seen in the young female rats may lead to potential treatment strategies against PD. 5 Many studies have shown that early life stress may lead to impaired brain development, and may be a risk factor for developing psychiatric diseases, including clinical depression. However, few studies have investigated the impact that early stress may have on the onset and development of neurodegenerative disorders such as PD. The study reported on in chapter 5 conjointly subjected rat pups to a maternal separation (MS) paradigm that is a well characterised model of adverse early life events, and a unilateral, intrastriatal injection of 6- OHDA. The combined effects of these models on motor deficits and brain protein levels were investigated. Specifically, the animals were assessed for behavioral changes at 28 days postlesion with a battery of tests that are sensitive to the degree of DA loss sustained. The results show that animals that had been subjected to MS display poorer performance in the vibrissae and single-limb akinesia test compared to non-MS control animals (that had also been subjected to the toxin exposure). In addition, there was a significant increase in the loss of TH staining in MS rats compared to non-MS ones. The results from this study therefore suggest that exposure to adverse experiences during the early stages of life may contribute towards making dopaminergic neurons more susceptible to subsequent insults to the CNS occurring during mature stages of life. Therefore, taken together, early exposure to stress may predispose an individual towards the onset and development of neurodegenerative disease, which especially becomes a threat during the later stages of adult life. Moreover, within the framework of these characteristics, the capacity of a widely-used pharmacological agent (statins) was tested for possible future therapeutic application in PD (chapter 7). Although the precise cause of sporadic PD remains an enigma, evidence suggests that it may associate with defective activity of complex I of the mitochondrial electron transport chain. Mitochondrial DNA transmit and express this defect in host cells, resulting in increased oxygen free radical production, depressed antioxidant enzyme activities, and greater susceptibility to apoptotic cell death. Simvastatin is a member of the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) group of drugs that are widely used for lowering cholesterol levels in patients who display elevated concentrations of low-density lipoprotein cholesterol. The study aimed to investigate the effects that statin-treatment have on motor-function and at the mitochondrial-protein level, using rotenone, a mitochondrial complex I inhibitor, as a rat-model of PD. Adult male Sprague-Dawley rats were treated either with simvastatin (6mg/day for 14 days) or with a placebo. Two different tests to assess motor function were used: The apomorphine-rotation test, and the vibrissae-elicited forelimb placement test. Following the drug administration protocol, the nigrostriatal tract was unilaterally lesioned with either rotenone (3 μg/4 μl) or, for the controls, were sham-operated by infusing the vehicle (DMSO:PEG) only. Five days later the rats were killed and a highly purified concentration of isolated mitochondria was prepared from the substantia nigra (SN) sections. 2- 6 Dimensional electrophoresis (2-DE) with subsequent identification of the spots using electronspray ionization quadruple time-of-flight mass spectrometrical (ESI-Q-TOF MS) was performed and the results BLAST-searched using bio-informatics tools for naming the identified peptides. The motor test results indicate that while unilateral rotenone causes behavioral asymmetries, treatment with simvastatin improved motor function relative to the rotenoneinduced ones. Mass Spectroscopy identified 23 mitochondrial proteins that differ significantly in protein expression (p < 0.05) following simvastatin treatment. The altered proteins were broadly classified according to their cellular function into 6 categories, with the majority involved in energy metabolism. This study effectively illustrated how neuroproteomics, with its sophisticated techniques and non-biased ability to quantify proteins, provides a methodology with which to study the changes in neurons associated with neurodegeneration. As an emerging tool for establishing disease-associated protein profiles, it also generates a greater understanding as to how these proteins interact and undergo post-translational modifications. Furthermore, due to the advances made in bioInformatics, insight is created concerning their functional characteristics. Chapter 4 summarises the most prominent proteomics techniques and discuss major advances made in the fast-growing field of neuroproteomics in PD. Ultimately, it is hoped that the application of this technology will lead towards a presymptomatic diagnosis of PD, and the identification of risk factors and new therapeutic targets at which pharmacological intervention can be aimed. The final chapter (chapter 8) provides a retrospective look at the academic work that had been performed for the purpose of this thesis, recaps on the main findings, and also highlights certain aspects of the project and provides relevant suggestions for future research. Lastly, the appendix provides a detailed overview of the methods followed for the experiments described in this thesis. It provides not only a comprehensive description of the techniques that had been followed, but provides information concerning the care taken with the animals (i.e. post-surgery) in order to control for the potential influence of experimental variables on the results.

Thesis presented in partial fulfilment for the degree of Master of Management (in the field of Public Sector Monitoring and Evaluation) to the Faculty of Commerce, Law, and Management, University of the Witwatersrand 2016 / The purpose of this research was to assess outcomes of the antiretroviral treatment intervention in Mankweng. The antiretroviral treatment intervention was conceived with the aim to reduce HIV transmission through viral load suppression. Literature has shown that viral load is used as a tool to measure the performance of the intervention and studies on viral load outcomes in rural settings of Limpopo are limited. For this reason, the research was focused on viral load suppression with the aim of (1) determining the proportion of adults with viral load suppression among people taking antiretroviral treatment for 12 months, and (2) identifying factors associated with failure to achieve viral load suppression among people on antiretroviral treatment for 12 months. Binomial logistic regression model was used to identify factors associated with failure to suppress viral load. This study used the theory of change to interpret its findings as well as theories of behavioural planning and self-regulation models to understand the logic that underpins the theory of change. The findings revealed that the majority (78%) of adults achieved viral load suppression, and a quarter of the individuals failed to suppress the viral load. There was no significant difference in baseline characteristics between people who achieved viral load suppression and those who did not. In addition, males, with a low CD4 and opportunistic illnesses when in the primary disease stages were more likely to fail to suppress the viral load. Moreover, people who were initiated on a 3-pill containing treatment and do not have social support were also likely to fail to achieve viral load suppression. Although the study showed a trend of likelihood towards failure to achieve viral load suppression, the estimates were not statistically significant. Theoretical arguments from this study suggest that failure to achieve viral load was attributed to poor adherence to treatment. This is supported by the logic that underpins the theory of change, in which the assumption of adherence was possibly violated. However, the results chain framework highlighted that the implementation of the intervention was effective as it led to good outcomes and an effective intervention. Drawing all this together, the study highlights the need for intensified adherence counseling during treatment in order to improve the performance of the intervention. Author: Ramatsobane Johanna Ledwaba, Thesis Title: Outcomes of the antiretroviral treatment intervention in Mankweng, Johannesburg, March 2016 / GR2018

Thesis (MTech (Environmental Health))--Cape Peninsula University of Technology, 2010 / This study aimed to evaluate the "Antiretroviral Programme" in two informal townships, Du Noon and Doombacht, in the Westem Cape, South Africa. It evaluated how AIDS patients access Antiretroviral Therapy (ART'), their knowledge of ART's efficacy, their adherence to ART as well as their experiences of the quality of service at the Du Noon Clinic. Employing a questionnaire survey among 124 (12%) respondents on ART of the registered 1, 050 clients at the Du Noon Clinic, a systematic sampling of every 9th client (of the 1,050) was done. To generate findings of a qualitative nature, the study also used focus group discussions with a total of 36 AIDS patients on ART (18 of this number were also part of the survey), 11 community health/home-based workers and in-depth interviews with 2 nurses in charge of the rollout programme at the Clinic. Based on the survey results, the study determined that 93% (n=115) of AIDS patients access ART at the Du Noon Clinic, 75% (n=93) of respondents reported to ART adherence and 75% (n=93) displayed an understanding of ART's efficacy. It also revealed that 77% (n=95) of AIDS patients made good comments regarding the quality of service at the Du Noon Clinic. However, 25% (n=31) of AIDS patients were not adhering to ART. A Mann Whitney U test confirmed a significant relationship between the respondents' length of time on ART and the increase in CD4 count (p=0.01). However, AIDS patients who adhered to ART with the same length of time on ART have a higher CD4 count difference (p=0.04). The focus group discussions revealed AIDS patients' experiences of lack of confidentiality at the Du Noon Clinic. In addition, in five of the six focus group discussions, respondents expressed concern over disability grants not being awarded to patients with CD4 counts 200 cells lML and below². Notably, more than half of the respondents have been on treatment for more than one year. The study concluded that ART access is humanizing in the Western Cape and controversial AIDS treatment discourse has not significantly influenced the perceptions of AIDS patients regarding ART's efficacy. A high percentage (75%) of AIDS patients were adhering to ART in Du Noon and Doombacht. Addressing concerns over lack of confidentiality when accessing ART at the Du Noon Clinic, as well as the quest for disability grants within the context of AIDS treatment, could have further improved ART adherence in these communities. The study recommends that monitoring and evaluation (M&E) should involve measuring factors that influence adherence alongside accessibility to ART. Secondly, there should be mechanisms in place to maintain confidentiality in accessing ART as it is with Voluntary

初級運動皮質直接負責運動控制。大量關於帕金森式癥(PD)的有效治療手段的研究已經證明，初級運動皮質在病理情況下的功能改變，直接與患者運動障礙相關。本論文的研究重點在於探索初級運動皮質在深部腦刺激治療帕金森氏症的運動障礙的過程中發揮的作用及其與運動學習功能障礙的聯繫。 / 丘腦底核深部腦刺激(STN-DBS) 已被廣泛應用於治療帕金森式症。雖然該項治療手段能顯著地改善患者的運動功能障礙，但其確切的治療機制仍未明確。理論上來說，丘腦底核深部腦刺激能夠直接啟動丘腦底核內部和其周圍很大範圍的神經組織，包括丘腦底核內部本身的神經元胞體，以及與其相連接的輸入輸出核團的神經元軸突。在丘腦底核眾多輸入核團之中，一個重要的神經輸入來自於初級運動皮質(MI)第五層的離皮質神經元(CxFn)，電刺激引起的逆行皮質啟動作用被提出，用於解釋丘腦底核深部腦刺激的治療機制。 / 為了研究逆行皮質啟動效應究竟如何在丘腦底核深部腦刺激的過程之中帶來治療效果，我們採用多通道神經電生理信號記錄系統在自由活動的單側帕金森大鼠的初級運動皮質進行鋒電位元和局部場電位元信號的記錄。實驗結果證明，當對丘腦底核進行高頻電刺激，在運動皮質第五層的離皮質神經元能成功記錄到保持固定延時的逆行鋒電位。由於增加刺激頻率會引起逆行鋒電位被成功記錄到的百分比下降，因此當深部腦刺激的頻率選擇在125Hz時，逆行鋒電位的放電頻率達到最高，而此刺激頻率正好與行為學實驗中帶來最佳治療效果的刺激頻率一致。於此同時，逆行皮質啟動作用還伴隨著初級運動皮質離皮質神經元的自發放電頻率增加、同步性爆發式放電減少等電生理信號特點。場電位分析的結果進一步表明，丘腦底核深部腦刺激減弱了病理情況下出現的beta波頻譜能量增高以及鋒電位-場電位相干性增強。更重要的是，我們發現只有逆行鋒電位被成功誘發，離皮質神經元的發放電機率才能被調節。這點有力地表明由電刺激隨機誘發的逆行鋒電位傳導至初級運動皮質，直接幹預並抑制了離皮質神經元在病理情況下的同步性爆發式放電活動，從而緩解了帕金森氏症的運動障礙。 / 另外，初級運動皮質並不僅僅是一個靜態的運動控制中樞，更為重要的功能在於它參與著與運動學習和運動記憶相關的動態資訊編碼。帕金森氏症患者普遍存在皮質可塑性減弱以及運動技能學習障礙。由於初級運動皮質分層結構的存在，層內神經元之間的突觸連接為神經可塑性提供了很好的結構基礎。因此，我們在初級運動皮質誘發在體長時程增強(LTP)，旨在研究與運動技能學習相關的皮質神經可塑性的動態變化過程，以及探索中腦多巴胺能投射系統對皮質神經可塑性的影響。 / 一方面，我們採用間斷性高頻刺激誘發在體長時程增強，證實六羥多巴損毀後皮質的長時程增強水準顯著下降。另一方面，我們設計前肢抓食的行為學範式用來評價動物在運動技能學習的不同階段皮質可塑性發生的動態變化。實驗結果表明，直接損毀皮質的多巴胺能輸入，模型組大鼠與假實驗組大鼠的行為表現在初期的技能獲取階段並無明顯差異，而只在後期的技能鞏固階段模型組大鼠表現出技能鞏固障礙。更為有趣的是，兩組行為學變化趨勢與各自的在體長時程增強的變化趨勢有很高的一致性。本研究表明多巴胺對初級運動皮質的支配在運動記憶的鞏固過程中起著關鍵作用。在帕金森氏症的病理情況下，多巴胺耗竭將影響皮質的突觸可塑性，從而造成帕金森患者在運動技能的鞏固階段表現出障礙。 / The primary motor cortex (MI) controls movement directly, but is an under-investigated brain region in the pathogenesis and treatment of Parkinsonian motor disability, when compared with the basal ganglia circuitry. In this study, the roles of MI in underlying the therapeutic action of surgical deep brain stimulation and motor learning impairment were investigated. / Deep brain stimulation of the subthalamic nucleus (STN-DBS) is now a recognized therapeutic option for Parkinson’s disease (PD). Although this surgical strategy provides behavioral benefits remarkably, its exact mechanism is still a matter of controversy. In principle, STN-DBS can directly activate a wide range of neuronal elements within the STN and surrounding areas. As the corticofugal neurons (CxFn) in the layer V motor cortex provide a major input to the STN, we hypothesized that the stimulation evoked antidromic cortical activation is involved in the therapeutic mechanism of STN-DBS. In the first series of experiments, we performed simultaneous recordings of multi-unit neuronal activities and local field potentials (LFPs) in MI in freely moving hemi-parkinsonian rats. By identifying stimulation evoked antidromic spike, which occurred at a fixed, short latency, CxFn located in the layer V MI were identified. Increasing stimulation frequency also increased failure rate of activation, resulting in a peak frequency of stochastic antidromic spikes at 125Hz STN-DBS, which was correlated with the optimal therapeutic efficacy observed in behavioral tests. Meanwhile, this antidromic effect was accompanied by the rectification of pathological neuronal activities including increased spontaneous firing rate, reduced burst discharge and synchrony among the CxFn. Field potential analysis revealed that STN-DBS alleviated the dominance of pathological beta band oscillation and spike-field coherence in the MI. More importantly, it was found that the firing probability of CxFn could only be modified following the occurrence of antidromic spikes, suggesting that direct interference of stochastic antidromic spikes with pathological neuronal activities underlies the beneficial effect of STN-DBS. / The MI is not simply a static motor control structure. It also contains a dynamic substrate that participates in motor learning or stores motor memory. In PD patients, loss of cortical plasticity and impaired motor learning is a common feature. As the intrinsic horizontal neuronal connections in MI are a strong candidate of cellular correlate for activity-dependent plasticity, in the second series of experiments, we developed in vivo long-term potentiation (LTP) technique in the MI to investigate the dynamics of cortical plasticity during motor skill learning and the role of the innervation by mesocortical dopamine input. Local depletion of dopamine in the primary motor cortex resulted in reduced performance in the forelimb reaching for food learning task. Although the performance of the PD rats in the initial learning phase was comparable to that of the sham-operated group, as training continued, these animals exhibited deficit in consolidating the motor skill. These deficits closely paralleled the impairment in training-enhanced synaptic connections in layer V neurons, and the in vivo LTP of evoked field excitatory postsynaptic potentials induced by intermittent high frequency stimulation. In addition, progressive recruitment of task-specific neurons was suppressed. Our study therefore revealed that dopamine depletion confined to the MI could lead to impairment in cortical synaptic plasticity which may preferentially affect the consolidation, but not the acquisition, of motor skills. These findings shed light on the cellular mechanisms of motor skill learning and could explain the decreased ability of PD patients in learning new motor skills. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Li, Qian. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 168-190). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese. / CHAPTER 1 --- p.1 / General Introduction --- p.1 / Chapter 1.1 --- Anatomical organization of the basal ganglia --- p.1 / Chapter 1.1.1 --- Overview of the basal ganglia circuit --- p.1 / Chapter 1.1.2 --- Cortico-basal ganglia-cortical circuit --- p.1 / Chapter 1.1.2.1 --- Direct and indirect pathway --- p.2 / Chapter 1.1.2.2 --- Hyperdirect pathway --- p.2 / Chapter 1.1.2.3 --- The midbrain dopamine system --- p.2 / Chapter 1.2 --- Striatum --- p.3 / Chapter 1.2.1 --- Cell types in the striatum. --- p.3 / Chapter 1.2.2 --- The Cortico-striatal system --- p.4 / Chapter 1.3 --- Subthalamic Nucleus --- p.5 / Chapter 1.3.1 --- Neuronal property of the STN. --- p.5 / Chapter 1.3.2 --- Electrophysiological property of the STN --- p.6 / Chapter 1.3.3 --- Cortico-subthalamic system --- p.7 / Chapter 1.3.4 --- Functional significance of the cortico-subthalamic and corticostriatal system. --- p.8 / Chapter 1.4 --- Parkinson’s disease --- p.9 / Chapter 1.4.1 --- Pathogenesis of PD --- p.9 / Chapter 1.4.2 --- Genetic risk factors of PD --- p.10 / Chapter 1.4.3 --- Progressive motor symptoms of PD --- p.11 / Chapter 1.4.4 --- Non-motor symptoms of PD --- p.13 / Chapter 1.4.5 --- Pathological neuronal rhythms in the basal ganglia of PD. --- p.16 / Chapter 1.5 --- Experimental studies of PD. --- p.18 / Chapter 1.5.1 --- Animal modeling of PD. --- p.18 / Chapter 1.5.2 --- Motor deficits evaluation in rodent models of PD --- p.21 / Chapter 1.5.3 --- Non-motor symptoms evaluation in experimental models of PD --- p.24 / Chapter 1.6 --- Deep Brain Stimulation --- p.27 / Chapter 1.6.1 --- DBS in alleviating Parkinsonian motor symptoms --- p.28 / Chapter 1.6.2 --- DBS in alleviating Parkinsonian non-motor symptoms --- p.29 / Chapter 1.6.3 --- Investigation of the STN-DBS mechanism. --- p.31 / Chapter 1.6.3.1 --- Local inhibitory effect within the STN --- p.32 / Chapter 1.6.3.2 --- Excitatory effect at output nuclei --- p.33 / Chapter 1.6.3.3 --- The de-coupling of soma and axons at system level --- p.34 / Chapter 1.6.3.4 --- Effects of DBS on abnormal rate or pattern --- p.35 / Chapter 1.6.3.5 --- Antidromic propagation of DBS effect towards cortex --- p.37 / Chapter 1.7 --- Objective --- p.38 / Chapter 1.8 --- Figures --- p.41 / CHAPTER 2 --- p.47 / General Methods --- p.47 / Chapter 2.1 --- Animals --- p.47 / Chapter 2.2 --- Stereotaxic surgery --- p.47 / Chapter 2.2.1 --- Preoperative preparation --- p.47 / Chapter 2.2.2 --- Anesthesia and craniotomy --- p.48 / Chapter 2.2.3 --- Induction of hemi-Parkinsonian rat model --- p.48 / Chapter 2.2.4 --- Electrode implantation techniques. --- p.49 / Chapter 2.3 --- Behavioral assessment. --- p.50 / Chapter 2.3.1 --- Apomorphine-induced contralateral rotation. --- p.50 / Chapter 2.3.2 --- Open field test --- p.50 / Chapter 2.4 --- STN-DBS protocol --- p.50 / Chapter 2.5 --- Electrophysiological data acquisition --- p.51 / Chapter 2.6 --- Data analysis --- p.52 / Chapter 2.6.1 --- Statistical analysis of behavioral data --- p.52 / Chapter 2.6.2 --- Electrophysiological data --- p.52 / Chapter 2.6.2.1 --- Stimulation artifact removal --- p.52 / Chapter 2.6.2.2 --- Multi-unit spike sorting --- p.53 / Chapter 2.6.2.3 --- Electrophysiological identification of pyramidal neuron and interneuron. --- p.54 / Chapter 2.6.2.4 --- Identification of antidromic cortical activation --- p.54 / Chapter 2.6.2.5 --- Discharge pattern classification --- p.54 / Chapter 2.6.2.6 --- Synchrony level evaluation --- p.55 / Chapter 2.6.2.7 --- Oscillatory rhythm characterization --- p.55 / Chapter 2.6.2.8 --- Coherence Level Measurement --- p.56 / Chapter 2.7 --- Histological verification --- p.56 / Chapter 2.8 --- Figures --- p.58 / CHAPTER 3 --- p.60 / Alleviation of Parkinsonian Motor Symptoms during Deep Brain Stimulation in Hemi-Parkinsonian Rats --- p.60 / Chapter 3.1 --- Introduction --- p.60 / Chapter 3.2 --- Materials & Methods --- p.61 / Chapter 3.2.1 --- Animals --- p.61 / Chapter 3.2.2 --- Chemicals --- p.61 / Chapter 3.2.3 --- Equipment --- p.61 / Chapter 3.3 --- Results --- p.62 / Chapter 3.3.1 --- Time course of the Apomorphine induced rotation behavior --- p.62 / Chapter 3.3.2 --- Dose-dependence of the Apomorphine induced rotation --- p.62 / Chapter 3.3.3 --- Acute behavioral response to STN-DBS. --- p.63 / Chapter 3.3.4 --- The dependence of STN-DBS effect on stimulation paradigm. --- p.64 / Chapter 3.3.5 --- Acute effects of STN-DBS on APO induced rotation. --- p.64 / Chapter 3.3.6 --- Long-term effects of STN-DBS on APO induced rotation --- p.64 / Chapter 3.3.7 --- Histological confirmation of the stimulation electrodes localization --- p.65 / Chapter 3.3.8 --- Loss of DA neurons in the SNc --- p.65 / Chapter 3.3.9 --- Reductions of the DA axon terminals in the striatum --- p.65 / Chapter 3.3.10 --- Chronic STN-DBS failed to rescue nigrostsriatal and striatal DA --- p.66 / Chapter 3.4 --- Discussion --- p.66 / Chapter 3.4.1 --- Neurotoxic mechanism of 6-OHDA --- p.66 / Chapter 3.4.2 --- Time course of dopamine degeneration induced by 6-OHDA --- p.66 / Chapter 3.4.3 --- Failure in observing worsened motor symptoms during low frequency STN-DBS. --- p.67 / Chapter 3.4.4 --- Experimental DBS based on rat model: does it mimic human case? --- p.67 / Chapter 3.4.5 --- Technical issues about STN-DBS --- p.69 / Chapter 3.5 --- Figures --- p.72 / CHAPTER 4 --- p.82 / Direct involvement of the Corticofugal Neurons in Motor Cortex during Therapeutic Deep Brain Stimulation --- p.82 / Chapter 4.1 --- Introduction --- p.82 / Chapter 4.2 --- Materials --- p.83 / Chapter 4.2.1 --- Animals --- p.83 / Chapter 4.2.2 --- Chemicals --- p.83 / Chapter 4.2.3 --- Equipment --- p.83 / Chapter 4.3 --- Results --- p.84 / Chapter 4.3.1 --- Identification of CxFn based on antidromic effect --- p.84 / Chapter 4.3.2 --- Antidromic spikes frequency correlates with therapeutic effect of STN-DBS. --- p.84 / Chapter 4.3.3 --- Pathological changes of neuronal firing rate in MI --- p.85 / Chapter 4.3.4 --- Only high frequency STN-DBS normalizes neuronal firing rate in MI --- p.86 / Chapter 4.3.5 --- Pathological changes of neuronal discharge pattern in MI --- p.88 / Chapter 4.3.6 --- Pathological synchrony of MI neuronal population, especially during burst discharge --- p.89 / Chapter 4.3.7 --- High frequency STN-DBS successfully suppresses synchronized burst discharge in MI --- p.89 / Chapter 4.3.8 --- Pathological β-band oscillatory activity in MI-LFPs induced by 6-OHDA lesion --- p.90 / Chapter 4.3.9 --- High frequency STN-DBS alleviates the β-band oscillation in MI-LFPs --- p.90 / Chapter 4.3.10 --- Synchronized bursting discharge correlates with oscillatory activity --- p.91 / Chapter 4.3.11 --- Pathological increased spike-LFP coherence level induced by 6-OHDA lesion --- p.92 / Chapter 4.3.12 --- High frequency STN-DBS modulated the spike-LFP coherence properties --- p.92 / Chapter 4.3.13 --- Antidromic spikes directly modulate the firing probability of CxFn --- p.93 / Chapter 4.3.14 --- Antidromic spikes modulate the firing probability of INs and non-CxFn nearby. --- p.94 / Chapter 4.3.15 --- The efficiency of antidromic cortical modulation depends on DBS frequency --- p.94 / Chapter 4.3.16 --- Orthodromic vs. antidromic effect: which one is responsible for the beneficial effect of DBS? --- p.95 / Chapter 4.3.17 --- Histology --- p.96 / Chapter 4.4 --- Discussion --- p.96 / Chapter 4.4.1 --- Origin of pathogenic rhythm in basal ganglia circuit --- p.96 / Chapter 4.4.2 --- Suppression of oscillatory synchronization equals to therapeutic effects of DBS? --- p.97 / Chapter 4.4.3 --- Beneficial effect of DBS corresponds to the topographic distribution of cortico-subthalamic projection. --- p.98 / Chapter 4.4.4 --- What is the reason for a stochastic pattern of antidromic activation effect? --- p.99 / Chapter 4.4.5 --- Desynchronization of pathological oscillatory rhythm by antidromic activation --- p.100 / Chapter 4.4.6 --- Antidromic vs. orthodromic: which is the cause of the beneficial effects of DBS? --- p.101 / Chapter 4.4.7 --- Wide propagation of antidromic effect by cortical horizontal circuits --- p.102 / Chapter 4.4.8 --- Significance of antidromic cortical activation in during STN-DBS --- p.102 / Chapter 4.4.9 --- Implication of antidromic activation effect on pathogenesis and treatment of PD --- p.104 / Chapter 4.5 --- Figures --- p.105 / CHAPTER 5 --- p.132 / Impaired Synaptic Plasticity in the Primary Motor Cortex after Dopamine Depletion: Potential Role in Motor Memory Consolidation --- p.132 / Chapter 5.1 --- Introduction --- p.132 / Chapter 5.1.1 --- Characteristics of motor learning --- p.132 / Chapter 5.1.2 --- Motor learning related cortical plasticity. --- p.133 / Chapter 5.1.3 --- Dopaminergic signals in the primary motor cortex --- p.134 / Chapter 5.1.4 --- Impaired cortical plasticity in PD --- p.135 / Chapter 5.1.5 --- Objective --- p.136 / Chapter 5.2 --- Materials --- p.136 / Chapter 5.2.1 --- Animals --- p.136 / Chapter 5.2.2 --- Chemicals --- p.136 / Chapter 5.2.3 --- Equipment --- p.136 / Chapter 5.3 --- Methods --- p.136 / Chapter 5.3.1 --- Functional mapping of the forelimb territory in MI --- p.136 / Chapter 5.3.2 --- Stereotaxic surgery --- p.137 / Chapter 5.3.3 --- Forelimb-reaching Task. --- p.137 / Chapter 5.3.4 --- In-vivo LTP Induction. --- p.138 / Chapter 5.4 --- Results --- p.139 / Chapter 5.4.1 --- Functional mapping of rat forelimb territory. --- p.139 / Chapter 5.4.2 --- Morphologies of evoked field potential response --- p.139 / Chapter 5.4.3 --- LTP of the early, monosynaptic plasticity within horizontal layer V MI --- p.140 / Chapter 5.4.4 --- LTP of the late, polysynaptic plasticity within horizontal layer V MI --- p.140 / Chapter 5.4.5 --- Impaired synaptic plasticity in MI after dopamine depletion --- p.140 / Chapter 5.4.6 --- Learning curve of forelimb-reaching task --- p.140 / Chapter 5.4.7 --- Physiologically enhanced cortical plasticity during motor learning --- p.141 / Chapter 5.4.8 --- Dynamic modulation of cortical neuronal activities during motor skill learning. --- p.142 / Chapter 5.4.9 --- Statistical analysis of ‘task related’ neuron’s modulation pattern. --- p.143 / Chapter 5.4.10 --- Loss of dopamine modulation in the MI --- p.144 / Chapter 5.5 --- Discussion --- p.144 / Chapter 5.5.1 --- Distinguishing between monosynaptic and polysynaptic transmission --- p.144 / Chapter 5.5.2 --- Artificially vs physiologically induced cortical plasticity. --- p.145 / Chapter 5.5.3 --- Cortical synaptic plasticity interprets motor learning dynamics --- p.146 / Chapter 5.5.4 --- Balance between neuronal recruitment and withdrawal in the consolidation stage --- p.147 / Chapter 5.5.5 --- Dopamine’s involvement in mediating the cortical synaptic plasticity. --- p.148 / Chapter 5.6 --- Figures --- p.150 / Conclusion --- p.162 / Abbreviations --- p.165 / References --- p.168

Choy Wai Yan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 98-122). / Abstracts in English and Chinese. / Thesis committee --- p.i / Statement --- p.ii / Abstract --- p.iii / Acknowledgements --- p.vi / General abbreviations --- p.viii / Abbreviations of chemicals --- p.x / Table of contents --- p.xi / List of figures --- p.xv / List of tables --- p.xviii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Severe acute respiratory syndrome (SARS) - An overview --- p.1 / Chapter 1.1.1 --- Epidemiology of SARS --- p.1 / Chapter 1.1.2 --- Clinical presentation of SARS --- p.2 / Chapter 1.1.3 --- Diagnostic tests of SARS --- p.5 / Chapter 1.1.4 --- Treatment of SARS --- p.7 / Chapter 1.2 --- Severe acute respiratory syndrome coronavirus (SARS- CoV) --- p.8 / Chapter 1.2.1 --- The etiological agent of SARS --- p.8 / Chapter 1.2.2 --- The coronaviruses --- p.9 / Chapter 1.2.3 --- Genome of SARS-CoV --- p.11 / Chapter 1.3 --- Spike (S) glycoprotein of SARS-CoV --- p.14 / Chapter 1.3.1 --- Functions of SARS-CoV S glycoprotein --- p.15 / Chapter 1.3.2 --- Receptors for S glycoprotein of SARS-CoV --- p.17 / Chapter 1.4 --- 3C-like protease (3CLPro) of SARS-CoV --- p.20 / Chapter 1.4.1 --- Extensive proteolytic processing of SARS-CoV replicase polyproteins --- p.20 / Chapter 1.4.2 --- SARS-CoV 3CLPro --- p.21 / Chapter 1.4.3 --- Substrate specificity of SARS-CoV 3CLPro --- p.22 / Chapter 1.5 --- Combating SARS - Vaccine and drug development --- p.24 / Chapter 1.5.1 --- Vaccine development against SARS --- p.24 / Chapter 1.5.2 --- Drug development against SARS --- p.25 / Chapter 1.6 --- Project objectives of this thesis --- p.27 / Chapter 1.6.1 --- Synthetic Peptide Studies on SARS-CoV S glycoprotein --- p.27 / Chapter 1.6.2 --- Synthetic Peptide Studies on SARS-CoV 3CLPro --- p.28 / Chapter 2 --- Materials and Methods --- p.30 / Chapter 2.1 --- Synthetic peptide studies on SARS-CoV S glycoprotein --- p.30 / Chapter 2.1.1 --- Bioinformatics analyses of SARS-CoV S gly- coprotein --- p.30 / Chapter 2.1.2 --- Peptide design and molecular modeling --- p.32 / Chapter 2.1.3 --- Solid phase peptide synthesis (SPPS) --- p.33 / Chapter 2.1.4 --- Peptide conjugation --- p.35 / Chapter 2.1.5 --- Immunization in rabbits and monkeys --- p.36 / Chapter 2.1.6 --- ELISA analysis --- p.37 / Chapter 2.1.7 --- Immunofluorescent confocal microscopy --- p.39 / Chapter 2.2 --- Synthetic peptide studies on SARS-CoV 3CLpro --- p.40 / Chapter 2.2.1 --- Protein expression and purification --- p.40 / Chapter 2.2.2 --- Solid phase peptide synthesis (SPPS) --- p.41 / Chapter 2.2.3 --- Peptide cleavage assay --- p.44 / Chapter 2.2.4 --- Molecular docking --- p.46 / Chapter 3 --- Results --- p.48 / Chapter 3.1 --- Synthetic peptide studies on SARS-CoV S glycoprotein --- p.48 / Chapter 3.1.1 --- General features and structural analyses of the S glycoprotein --- p.48 / Chapter 3.1.2 --- Peptides design and synthesis --- p.53 / Chapter 3.1.3 --- ELISA analysis and immunofluorescent con- focal microscopy --- p.55 / Chapter 3.2 --- Synthetic peptide studies on SARS-CoV 3CLpro --- p.62 / Chapter 3.2.1 --- Substrate specificity of SARS-CoV 3CLPro . . --- p.62 / Chapter 3.2.2 --- Molecular docking of SARS-CoV 3CLPro and peptide substrates --- p.74 / Chapter 4 --- Discussion --- p.78 / Chapter 4.1 --- Synthetic peptide studies on SARS-CoV S glycoprotein --- p.78 / Chapter 4.1.1 --- Synthetic peptides elicited SARS-CoV specific antibodies --- p.78 / Chapter 4.1.2 --- Factors affecting the specificity and antigenic- ity of synthetic peptides --- p.80 / Chapter 4.1.3 --- Next step towards vaccine development --- p.83 / Chapter 4.1.4 --- A synthetic peptide-based approach --- p.84 / Chapter 4.2 --- Synthetic peptide studies on SARS-CoV 3CLpro --- p.86 / Chapter 4.2.1 --- A comprehensive overview of the substrate specificity of SARS-CoV 3CLpro --- p.87 / Chapter 4.2.2 --- Sequence comparison between SARS-CoV 3CLpro cleavage sites --- p.90 / Chapter 4.2.3 --- A rapid and high throughput approach to screen protease substrate specificity --- p.94 / Bibliography --- p.98

Early deterioration and long-term recurrence were common after stroke or transient ischemic attach (TIA), however, it is unclear whether they were correlated with active embolization and the consequent new cerebral infarct in acute phase. By employing TCD and diffusion weighted imaging (DWI), we studied the significance of the progression of MES and infarcts during acute phase on the clinical outcomes. We found that the disappearance of MES was correlated with better improvement on day 7 of recruitment; for the long-term outcome, occurrence of exacerbating infarct tended to predict recurrent stroke. Treatment aiming to reduce MES and prevent infarct exacerbation in acute phase may improve the prognosis after stroke. / Finally, one study was performed to assess the changes of hemodynamic parameters after stenting of severe stenosis in the MCA. We aimed to investigate whether TCD can reflect the lumen changes after revascularization and detect hyperperfusion. The findings showed that the velocity of stented MCA in most patients normalized within 24 hours after procedure, but the role of TCD in detecting restenosis in long run needed to be verified; no one suffered from hyperperfusion during the period of our study. The long-term outcomes of patients with normalized velocity versus those with persistently high velocity needed to be further studied. Apart from the velocity changes, changes of the collateral flow after intervention may also be an important part of hemodynamic changes. (Abstract shortened by UMI.) / It was suggested that anti-platelet therapy can reduce the MES, but little was known about the efficacy of low molecular weight heparin (LMWH) although in theory LMWH can reduce the red fibrin-dependent thromboemboli. As a sub-analysis of Fraxiparine in Ischemic Stroke (FISS)-tris study, our study did not show advantages of LMWH in eliminating MES compared with aspirin. / Previous studies showed the accuracy of TCD in diagnosis of middle cerebral artery (MCA) stenosis was variable and the positive predictive value (PPV) was less than 50% in a recent report. One of the important reasons was that most criteria were based on the velocity-only method, ignoring other non-velocity information. Thus, we tried to establish new diagnostic criteria by means of designing an assessment form which integrated more characteristics apart from the velocity acceleration. A composite score for each MCA was calculated according to following parameters in the form: Velocity Scale (score 0-6 for peak systolic velocities&lt;140 to &ge;300cm/s), Hemodynamic Scale (score 0-5 for focal or diffuse velocity increase; score 0-6 for differences between bilateral MCA; score 17 for damping velocity), Spectrum Scale (score 0-2 for normal spectrum, turbulence and musical murmurs). Our results showed that compared with the previously reported criteria, the score calculated from the assessment form yielded much more balanced accuracy against magnetic resonance angiography (MRA) and digital subtraction angiography (DSA). However, the composition of the assessment form was only based on personal experience and need to be further modified. Multicenter studies with large sample size are also needed to confirm the advantages of this new method. / Second, we performed three studies to investigate the relationship between the progression of MES and the short or long-term outcome and the relationship between MES and different treatments. / Hao, Qing. / Adviser: Ka Sing Wong. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3419. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 155-181). / 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, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

For the purpose of developing an effective therapeutic strategy for HSCR, the enteric neural crest stem cells were investigated firstly which were isolated from the E14.5 mouse embryonic gut, cultured as neurospheres and characterized by multiple immunofluorescence and reverse transcription-PCR, population doubling time, frequency of forming secondary neurospheres and limited dilution assay. In the differentiation culture medium, several types of cells were induced to form from the neurospheres derived from single cells. Hence the putative enteric neural crest stern cells, which were isolated from the embryonic mouse gut tube and cultured as neurospheres for many passages ex vivo with the demonstrated capacity of proliferation, self-renewal and differentiation, showed properties of stem cells. / Hirschsprung's disease (HSCR) is caused by the absence of the enteric neural crest-derived neurons at the distal region of the gut. Cell-based therapy using stem cells or progenitors gives the potential to supplement these missing enteric neurons in the gut. Enteric neural crest stem cells isolated from the human or rodent gut can give rise to neurons and glia after they are transplanted into the recipient guts of the mouse or rat. However, numbers of issues are unresolved about the basic biology of the enteric nervous system, the characteristics of the stem cells isolated from the enteric nervous system and the biological significance of these cells in prenatal and postnatal periods. In this study, the characteristics and therapeutic potential on HSCR of the enteric neural crest stem cells were explored. / In addition to the above, a recombination organotypic gut culture ex vivo showed that the colonization of enteric neural crest-derived cells in the recipient gut was influenced not only by the genotypes of enteric neural crest-derived cells themselves but also the microenvironment of the gut through which enteric neural crest-derived cells migrated. For instance, the developmental stage of the recipient gut and also the presence of endogenous enteric neural crest-derived cells along the migratory pathway of neural crest-derived cells both affected the extent of the migration and colonization of exogenous enteric neural crest-derived cells and stem cells. The gradual maturation and differentiation of the neighboring structures, such as the smooth muscle layer, during the time period of the enteric neural crest cells migration, might also suggest that these neighboring tissues may have a role in regulating the neural crest-derived cells migration. / In conclusion, enteric neural crest stem cells isolated from the embryonic mouse gut tube showed properties of stem cells, and had the potential to compensate missing enteric neural crest-derived cells both ex vivo and in vivo. However, the colonization of enteric neural crest-derived cells in the developing gut was affected cell-autonomously and also by the microenvironment of the gut and the presence of existing enteric neural crest-derived cells. / Their potential applications in the transplantation experiments were shown by transplantation of the neurospheres isolated to the gut tube maintained in an organotypic culture or to the descending colon of neonates at postnatal day 7. The development of the enteric neural crest stern cells from the neurospheres was found to be compatible to endogenous enteric neural crest-derived cells in the recipient gut as evidenced by the formation of interconnected cellular networks of donor stem cells and endogenous neural crest-derived cells. The enteric neural crest stem cells also possess the potential to compensate the loss of enteric neural crest-derived cells ex vivo and in vivo in recipient prenatal and postnatal guts. / Bao, Lihua. / Adviser: Wood Yee Chan. / Source: Dissertation Abstracts International, Volume: 73-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 208-228). / 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.

阻塞性睡眠呼吸暂停（OSA）是一种常见的睡眠障碍，睡眠过程中反复发作的气道阻塞，导致间歇性低氧血症。OSA 中的間歇性缺氧（IH）一直被视為一個主要致病因素。會影響神經認知功能，包括記憶障礙，遲鈍的反應和其它。以前的研究提示氧化应激产物（ROS）和细胞凋亡是間歇性缺氧引起的认知功能障碍的主要機制之一。然而，确切的机制仍然知之甚少，并没有得到解决。我们基于間隙性缺氧 （IH）的动物模型的实验结果首次发现，即在IH 模型中海馬長時程增強（LTP）的降低，以及腦源性神經營養因子（BDNF）的表达减少。同時我們發現，大脑内注射BDNF 可以有效地恢复LTP 的幅度。因此，我们的研究提供了一种新的可能机制，即在缺乏脑源性神经营养因子可能是阻塞性睡眠呼吸暂停導致的伴有脑功能障碍一个关键因素。 / Ampakine 是一種AMPA 受體調節劑，更重要的是可以增加腦內BDNF 的表達。在这项研究中，我們在不同缺氧時間處理的動物模型中通过腹部注射ampakine 來觀察其效應。我們使用了四组成年雄性小鼠，其中組接受7 天IH处理，另外两组接受14 天缺氧处理。所有四组均分别接受腹腔ampakine 和对照生理盐水注射。 IH 模式仍然是氧含量在90 秒内从21 降到10%，再回复到21%。缺氧时间是每天8 小時周期。从整个IH /正常氧环境的第一天开始，八臂放射迷宮被用来研究参考记忆和工作记忆的表现。然后，我们对脑源性神经营养因子，活性氧和细胞凋亡的分子标记和海马的树突棘形态的表达进行了检查， 海馬突触可塑性的表現，包括E-LTP，L-LTP 也都被檢測。 / Western blot 分析显示，ampakine 注射有效恢复了IH 導致的海马BDNF 水平下降。同时， 我們也發現在ampakine 注射組中ROS 的表达减少，细胞凋亡的减轻，其中包括内质网应激诱导的细胞凋亡。树突棘被認為是海马突触可塑性的结构基础之一。高尔基体染色也表明， ampakine 注射IH 成功回復了7 天IH 導致的較大的，成熟树突棘的減少。 / 此外，八臂放射迷宮的结果表明，无论是参考记忆和工作记忆在7 天IH和14 天IH 均有受損表現。但是，ampkine 的使用同樣挽救了IH 引起的這些记忆障碍。 / 最後，通過研究AMPA 受體調節劑（ampakines）對IH-誘導的神經認知功能障礙及長時程增強障礙影響，我們發現進一步的闡明BDNF 在OSA 所起的重要作用。這些結果也將探索新的藥物治療的OSA 了新的思路。 / 阿爾茨海默病（AD），也叫老年癡呆癥，在65 歲的人的失憶症中，是最常見的原因，也是最常見的神經退行性疾病。 AD 的原因並不清楚，其起病也並不明顯。它的特點是逐漸喪失記憶，語言障礙及其他認知功能障礙，這些症狀可能會變得明顯。在AD 中，兩種蛋白質聚集體的參與和特點的AD 病理澱粉樣斑塊，由澱粉樣蛋白-β 肽，並導致細胞外病變和tau 蛋白纏結，這是由過度磷酸化的絲微管相關蛋白tau，並導致細胞內的病變。 / 鐵是最豐富的微量金屬，在大腦中參與範圍廣泛的細胞過程的運作。然而，鐵臭名昭著的另一方面是其強大的氧化催化性能。事實上，失調的鐵已被發現與細胞老化和各種各樣的神經退行性疾病有牽連。鐵在突觸功能的重要性是對突觸的影響，例如其可以順行軸突運輸突觸功能區域，這也是阿爾茨海默病中的澱粉樣蛋白斑的沉積的起始部位。然而，到現在，鐵的積累是如何影響突觸功能以及更普及的大腦功能很少被研究。 / 為了調查是否高鐵食有任何正常或阿爾茨海默氏病的影響，我們在實驗中引入了APPswe/ps1 轉基因小鼠，這是一個經典的老年癡呆症的疾病的動物模型。研究中，我們使用四組動物模型，即野生型（WT）和APPswe/ps1 小鼠（TG），每組給予至少10 個月正常（ctrl）的食和高鐵（HI）食。 / 海馬LTP 記錄表明，野生小鼠與正常食（WT-HI）的海馬長時程增強下降。 Tg-ctrl 組也相比wt-ctrl 組顯示LTP 水準下降，包括E-LTP 和L-LTP。引人注目的是，高鐵食下的APPswe/ps1 下顯示了被提高和恢復的海馬長時程突觸可塑性。 / 八臂放射迷宮的結果還表明，與高鐵食的野生型以及正常食的APPswe/ps1，無論是在參考記憶體或工作記憶，比野生型與正常食組有較差的記憶水準。同樣，我們驚訝地發現，和APPswe/ps1 正常食的小鼠相比，給予高鐵食的APPswe/ps1 組的迷宮成績要好得多,几乎回复到和野生型对照组一样的水平。 / 這些結果表明，鐵在阿爾茨海默病的功能是非常複雜的，可能會對其神經可塑性顯示雙相調節作用特性。詳細機制有待進一步探討。 / Obstructive sleep apnea (OSA) is a common sleep disorder, characterized by repeated episodes of airway obstruction during sleep resulting in intermittent hypoxemia. Previous studies proposed that reactive oxygen species (ROS) and apoptosis caused by intermittent hypoxia (IH) contributed to cognitive deficits. However, the exact mechanism is still poorly understood and not settled. Our recent studies, for the first time, showed that there is decreased expression of brain-derived neurotrophic factor (BDNF) in the hippocampus and impairment in long-term potentiation (LTP). Intra-brain injection of BDNF can effectively restore the magnitude of LTP. Thus, our study provides a novel mechanism and insight in the etiology of OSA-induced brain dysfunction in that lacking BDNF could be a critical factor. / In this study, ampakine application was used as “BDNF raiser“ during 7-day IH and 14-day IH treatment by intraperitoneal (i.p.) injection. Four groups of adult male mice were used, two of them exposed to 7-day IH and two of them exposed to 14-day IH, each received either vehicle or ampakine i.p. injection. The paradigm of IH consisted of cycles of oxygen levels between 10% and 21% every 90s during the daytime for 8 hrs. Radial arm maze was used to investigate the performance of reference memory and working memory during the whole IH/ normoxia treatment from the first day. After that, expression of BDNF, ROS and molecular markers of apoptosis and morphology of hippocampal dendritic spines were examined, together with the investigation of both hippocamal synaptic plasticity, including early phase LTP (E-LTP) and late phase L-LTP (L-LTP). / Ampakine treatment restored the decreased level of hippocampal BDNF in the IH-treated group, as revealed by Western blot. Meanwhile, decreased ROS expression and alleviated cell death, including ER stress induced-apoptosis are all found in those ampakine injected groups. Golgi staining also showed that ampakine injection IH treatment rescued the decrease of mature dendritc spines, which is the structural basis of hippocampal synaptic plasticity, under 7-day IH treatment. Hippocampal long-term synaptic plasticity, which underlies the proposed mechanism of memory, was also found reversed in those ampakine injected groups, compared with groups under IH treatment. / Furthermore, results of radial arm maze showed that both the reference memory and working memory are impaired by 7-day IH treatment or 14-day IH treatment. However, the application of ampakine rescued IH-induced memory deficits. / Finally, by studying the effects of the ampakines on IH-induced neurocognitive dysfunction and LTP impairment, the role played by BDNF in OSA was further elucidated. These results were shed new lights on the exploration of novel pharmacological treatments in the OSA. / Alzheimer’s disease is the most common cause of dementia among aged people. The causes of AD are not clear and onset of the disease is also not obvious. Iron is the most abundant trace metal in the brain and dysregulation of iron has been implicated in cell aging and a wide variety of neurodegenerative diseases including Alzheimer disease. However, up to now, very little is known about how iron accumulation is involved in Alzheimer disease. / To investigate whether high iron diet has any effects on normal or Alzheimer’s disease, we introduced APPswe/ps1 transgenic mice, an Alzheimer’s disease animal model, and used four groups in our study, namely wild type (wt) and APPswe/ps1 mice (tg), each with normal (ctrl) diets and high iron (HI) diet for at least 10 months. / Hippocampal LTP recording showed that wild type with high iron diet (wt-HI) decreased than that of wt-ctrl group. Tg-ctrl group also displayed decreased LTP level, including E-LTP and L-LTP, than that of wt-ctrl group. Strikingly, that of APPswe/ps1 under HI diets rescued the impaired hippocampal long-term synaptic plasticity than that of APPswe/ps1 mice under normal diets. / Results from radial arm maze also showed that both APPswe/ps1 with normal diet and wild type with HI diet had worse performance, either in reference memory or working memory, than those of wild type with normal diets. Again, it is surprised to find that performances of tg-HI group were much better than APPswe/ps1 mice under normal diet. / These results showed that the function of iron are very complicated, may have different effects on neural function of normal and AD objects. The detailed mechanisms needs to be further explored. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Xie, Hui. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 200-225). / Abstracts also in Chinese. / Declaration --- p.II / ABSTRACT OF THESIS ENTITLED --- p.III / 中文摘要 --- p.VII / Acknowledgements --- p.XI / List of abbreviations --- p.XIII / List of publications --- p.XVI / Chapter CHAPTER 1 --- INTRODUCTION --- p.4 / Chapter 1.1 --- Overview of the study --- p.4 / Chapter 1.2 --- Obstructive sleep apnea --- p.7 / Chapter 1.2.1 --- Epidemiology --- p.8 / Chapter 1.2.2 --- Pathogenesis --- p.10 / Chapter 1.2.3 --- Pathophysiologic Consequences --- p.11 / Chapter 1.2.4 --- Diagnosis --- p.14 / Chapter 1.2.5 --- Treatment --- p.15 / Chapter 1.3 --- Memory and long-term potentiation --- p.17 / Chapter 1.3.1 --- Memory --- p.17 / Chapter 1.3.2 --- Hippocampal Synaptic plasticity --- p.19 / Chapter 1.3.3 --- Dendritic Spines --- p.23 / Chapter 1.4 --- Brain-derived neurotrophic factor --- p.35 / Chapter 1.4.1 --- Introduction of BDNF --- p.35 / Chapter 1.4.2 --- BDNF and synaptic plasticity --- p.36 / Chapter 1.5 --- Intermittent hypoxia impaired memory and neuroplasticity --- p.38 / Chapter 1.5.1 --- Clinical and basic studies on IH-induced neurological dysfunction --- p.38 / Chapter 1.5.2 --- Current mechanisms of IH-induced neurological dysfunction --- p.39 / Chapter 1.5.3 --- ROS generation and intermittent hypoxia --- p.41 / Chapter 1.5.4 --- Critical role of decreased BDNF expression in chronic intermittent hypoxia --- p..46 / Chapter 1.6 --- Ampakine --- p.48 / Chapter 1.6.1 --- Effects of ampakine on receptor activities --- p.49 / Chapter 1.6.2 --- Effects of ampakine on synaptic transmission --- p.50 / Chapter 1.6.3 --- Effects of ampakine on long-term potentiation --- p.52 / Chapter 1.6.4 --- Ampakine, BDNF and neurological disease --- p.53 / Chapter CHAPTER 2 --- METHODS --- p.61 / Chapter 2.1 --- Experimental procedure --- p.61 / Chapter 2.1 --- Animal model of Obstructive Sleep Apnea --- p.62 / Chapter 2.1.1 --- Chronic Intermittent Hypoxia --- p.62 / Chapter 2.1.2 --- Oxygen saturation measurement under normoxia and intermittent hypoxia --- p.64 / Chapter 2.1.3 --- Body weight during hypoxia treatment --- p.64 / Chapter 2.2 --- Western Blot Analysis --- p.65 / Chapter 2.3 --- ROS measurement --- p.67 / Chapter 2.4 --- Golgi staining --- p.67 / Chapter 2.4.1 --- Analysis of spine density --- p.68 / Chapter 2.4.2 --- Measurement of dendritic spines --- p.68 / Chapter 2.5 --- Electrophysiological Experiments --- p.69 / Chapter 2.5.1 --- Brain Slice Preparation --- p.69 / Chapter 2.5.2 --- Multi-electrode Recording Setup (MED64) --- p.70 / Chapter 2.5.3 --- Slice Superfusion --- p.72 / Chapter 2.5.4 --- Field Potential Recordings --- p.73 / Chapter 2.5.5 --- LTP Induction Protocol --- p.74 / Chapter 2.6 --- Radial arm maze --- p.76 / Chapter CHAPTER 3 --- RESULTS --- p.91 / Chapter 3.1 --- Molecular detection under IH treatment and ampakine injection --- p.91 / Chapter 3.1.1 --- BDNF expression under IH treatment and ampakine injection --- p.91 / Chapter 3.1.2 --- ROS measurement under IH treatment and ampakine injection --- p.92 / Chapter 3.1.3 --- Involvement of ER stress during IH treatment --- p.93 / Chapter 3.2 --- Changes of dendritic spines under IH treatment and ampakine injection --- p.100 / Chapter 3.2.1 --- Changes of total dendritic spine density under IH treatment and ampakine injection --- p.100 / Chapter 3.2.2 --- Changes of different dendritic spine density under IH treatment and ampakine injection --- p.101 / Chapter 3.2.3 --- Changes of dendritic spine morphology under IH treatment and ampakine injection --- p.103 / Chapter 3.3 --- IH-induced impairment in hippocampal synaptic plasticity --- p.110 / Chapter 3.3.1 --- E-LTP measurement of 7-day intermittent hypoxia treatment in long-term synaptic plasticity --- p.110 / Chapter 3.3.2 --- L-LTP measurement of 7-day intermittent hypoxia treatment in long-term synaptic plasticity --- p.111 / Chapter 3.3.3 --- E-LTP measurement of 14-day intermittent hypoxia treatment in long-term synaptic plasticity --- p.112 / Chapter 3.3.4 --- L-LTP measurement of 14-day intermittent hypoxia treatment in long-term synaptic plasticity --- p.113 / Chapter 3.4 --- Behavioral studies under IH treatment and ampakine injection --- p.119 / Chapter 3.4.1 --- Reference memory test under IH treatment and ampakine injection --- p.119 / Chapter 3.4.2 --- Working memory measurement under IH treatment and ampakine injection --- p..122 / Chapter CHAPTER 4 --- DISCUSSION --- p.140 / Chapter 4.1 --- Molecular changes under IH treatment and ampakine application --- p.140 / Chapter 4.1.1 --- Intermittent hypoxia down regulate BDNF expression in hippocampus while ampakine injection rescued IH-induced decreased BDNF level --- p.140 / Chapter 4.1.2 --- Ampakine injection against ROS and apoptosis --- p.143 / Chapter 4.1.3 --- Involvement of ER stress-induced apoptosis during IH treatment --- p.145 / Chapter 4.2 --- Changes of spine morphology and density under IH treatment and ampakine injection --- p.146 / Chapter 4.3 --- Ampakine rescued hippocampal synaptic plasticity --- p.152 / Chapter 4.4 --- IH impaired reference memory and working memory --- p.156 / Chapter 4.5 --- Summary --- p.160 / Chapter Chapter 5 --- Effects of High-iron diet in Alzheimer’s Disease --- p..164 / Chapter 5.1 --- Overview of the study --- p.164 / Chapter 5.2 --- Introduction --- p.166 / Chapter 5.2.1 --- Alzheimer's disease --- p.166 / Chapter 5.2.2 --- Function of iron in brain --- p.167 / Chapter 5.2.3 --- Involvement of iron in oxidative damage --- p.168 / Chapter 5.2.4 --- Role of iron in neurodegeneration diseases --- p.168 / Chapter 5.2.5 --- Role of iron in Alzheimer's disease --- p.169 / Chapter 5.2.6 --- Deleterious effects of iron in memory function --- p.171 / Chapter 5.3 --- Methods --- p.172 / Chapter 5.3.1 --- Experimental design --- p.172 / Chapter 5.3.2 --- T-maze --- p.172 / Chapter 5.4 --- Results --- p.174 / Chapter 5.4.1 --- Validation of animal model of Alzheimer's disease --- p.174 / Chapter 5.4.2 --- Examination of normal and high iron diet on body weight --- p.174 / Chapter 5.4.3 --- Effects of Aβ accumulation and high-iron diet on hippocampal synaptic plasticity --- p.175 / Chapter 5.4.4 --- Effects of Aβ accumulation and high-iron diet on spatial memory measured by T-maze --- p.177 / Chapter 5.4.5 --- Effects of Aβ accumulation and high-iron diet on reference memory and working memory measured by radial arm maze --- p.178 / Chapter 5.5 --- Discussion --- p.180 / Chapter Chapter 6 --- General discussion --- p.195 / Reference --- p.200

Thesis (M. A. (Social Work)) -- University of Limpopo, 2004. / The aim of this study was to explore the impact of culture on the prevention and reatment of HIV/AIDS amongst people in low-resourced areas like Malamulele. he study focused on the lifestyles, beliefs, attitudes and perceptions around ultural elements and practices, which might impact negatively on the prevention nd treatment of the HIV/AIDS epidemic. There were three groups of research espondents namely: learners from three high schools in Malamulele, some arents of the learners and the traditional/cultural leaders. The researcher ollected both qualitative and quantitative data. The data was gathered through he use of an interview schedule (questionnaire), focus group discussions and ound-table discussion sessions. The data was presented, analysed and nterpreted by means of tables and charts. t was found that people in low-resourced (rural) areas have little knowledge about HIV/AIDS, causes, symptoms and how the disease is transmitted. Despite the fact that awareness and educational campaigns and programmes are being rendered, people in low-resourced (rural) areas have little knowledge and needed skills about prevention and treatment of the pandemic. Polygamy and extra-marital relations by men is still highly valued and viewed at high esteem. Religious structures seem to be detached to the issue of HIV/AIDS as they mentioned that talking about HIV/AIDS is immoral and against their principles. The study also tried to explore the extent to which people in low-resourced areas view and use condoms as a protective means.