2,231 research outputs found
"After this I learned". Moral and Cultural Voices in Chinese Children's Personal Narratives about Peer Conflict
No full textPermission to publish this paper was given by the author. It was submitted on a CD.Bruner (1990) proposed that sharing personal narratives is critical to social and moral development. Stories are told when something goes awry in human interaction. As we tell stories, we attempt to position ourselves vis-à-vis the other actors in our stories, those listening to our story, and the standards and norms of our larger cultural traditions (Bamberg, 2003). Although considerable work has examined parent-child narrative practices in China, no studies have looked at conflict narratives in Chinese elementary schoolers. We have studied 152 stories by Chinese 4th – 6th graders about ―a conflict that really happened to you.‖ Quantitative results showed unexpected grade effects, with firth graders exceeding the older and younger children in their reports of moral lessons, puzzlement and positive resolution of their conflicts. They were the most skilled appropriators of mainstream culture and values that approximate Confucian teachings. Qualitative analyses revealed children‘s use of other resources such as popular culture to form distinctive cultural voices. Both quantitative and qualitative analyses guide our discussion of children‘s use of narrative to position the self vis-à-vis cultural traditions undergoing rapid change in China.This paper was read and approved by Drs. Marsha Walton, Christopher Wetzel, Yeh Hseueh and Natalie Person
The 3, 4, 5 literature : ideopolitical-moral education in Mainland China as a barometer of political and economic change
No full textEThOS - Electronic Theses Online ServiceGBUnited Kingdo
Shifting Selves: Home beyond the House - A Study of Ageing, Housing and Wellbeing of Older Chinese Migrants to New Zealand
No full textOlder Chinese immigrants are one of the largest ethnic ageing groups in New Zealand. However, people‘s everyday experiences of settling in a new and unfamiliar environment have been largely overlooked, particularly for older adults. This research explores the biographies, identities and everyday experiences of filial piety among older Chinese immigrants. Particular consideration is given to the role of filial piety in participants‘ housing and ageing experiences. This research is one of the first explorations of Chinese immigrant ageing in place, which also considers changing enactments of filial piety. The research is informed by a hybrid narrative approach that draws on episodic, go-along and fangtan interview techniques used with 32 older Chinese immigrants in Auckland and Hamilton. Findings support the importance of exploring positive experiences of migration and ageing. Older Chinese immigrants do often experience biographical disruptions and status-discrepancies when they move from China to New Zealand. However, in response, the participants engage in positive activities such as gardening and art as a means of cultivating a new sense of self and place in a new land that is compatible with their existing identities as older Chinese adults. The analysis explores the material-mediated basis for participant adjustment and acculturation. Through adaptive acculturation, older Chinese immigrants‘ abilities for both integrating into the host culture and maintaining their ethnic identities are realised. The analysis also demonstrates that traditional Chinese aged care models of family support with high level of intergenerational co-residence are evolving to encompass practices of filial piety at a distance and to encompass more pluralistic familial living arrangements. The analysis also demonstrates the importance of considering how ageing occurs beyond physical spaces and within cultural, social, relational and imagined landscapes. The analysis shifts away from the focus in existing literature on how older Chinese immigrants are passively transformed into minority subjects to how they are transforming themselves through migration and their efforts to age well in New Zealand
Li yong lin chuang shen he ji hua jia qiang Xianggang de lin chuang guan zhi
No full textPh.D.Clinical audits aim at creating a sustainable quality improvement process, and that is achieved by continuous systematic patient outcome data tracking with consistent follow-up criteria. Previous clinical audit studies focused mainly on its application in intervention effectiveness measurement and analysis of hospital service quality. The compliance on risk preventive model formulation could also be found in some studies. Recent researches on quality improvement largely relied on data collected by the National Surgical Quality Improvement Program (ACS-NSQIP) of the American College of Surgeons. This United States-based clinical record platform that is highly acknowledged on improving patient outcome at the affiliated hospitals. Alongside the rising trend of utilising clinical audit projects in clinical governance enhancement, there is a growing importance of optimising audit programme design, application, and customisation. However, whether it is beneficial to conduct a regional-wide or a department-focused clinical audit in terms of improving surgical outcome quality is unknown. In this thesis, we examine the use of regional and departmental audit programmes – Surgical Outcomes Monitoring and Improvement Programme (SOMIP) and Post-operative Complication Monitoring Programme (PPCMP). Studying these the local programmes would reinforce our knowledge on the benefit of clinical audit programme implementation in Hong Kong. We utilise clinical audit to investigate clinical intervention efficiency and administrative phenomenon in Hong Kong. We also establish locally relevant recommendation on launching an in-house clinical audit programme.Methods and results1) Tackling surgical site infections with specific care bundle in elective hepatobiliary and pancreatic surgeryPost-operative surgical site infection (SSI) is associated with a prolonged hospital stay, and increased post-operative morbidity and mortality. A team-specific SSI care bundle was designed and implemented in the Hepato-biliary and Pancreatic (HBP) surgical team at the Department of Surgery of PWH in 2009. The bundle serves the purpose to reduce SSI in elective surgery. We evaluated the efficiency of SSI care bundle with the SOMIP clinical audit data.1,319 cases were captured in the 6 years period and there were 139 (10.5%) SSI incidence observed. Pre- and post-intervention analysis was performed with the χ² test, it suggested that surgical site infection (SSI) rate significantly dropped (21.7% vs. 8.7%, OR=0.346, 95% C.I.=0.190–0.629; p<0.001). No significant difference on SSI in the subsequent years could be observed and the rates of SSI had maintained between 7.3% and 9.3% The data confirmed a positive impact of SSI care bundle on the reduction of post-operative SSI, and such positive impact remained sustainable in subsequent years when the care bundle is applied in long-term. (Further described in Chapter III)2) The “weekend effect” in emergency general and specialty surgeryIt is believed the weekend service quality may be relatively inferior as a result of the lack of senior surgeons, less available facilities and longer waiting time. The observation of a higher mortality rate among patients admitted over the weekend compared to the weekday is known as the “weekend effect”. The effect would be different according to operative magnitudes, surgical types and the size of surgical units. This study aimed to close our knowledge gap on the presence of “weekend effect” in emergency surgery services from 2010 to 2014 at the PWH Department of Surgery. Individual analysis was conducted respectively for general surgery and specialty surgery.1,860 patients underwent emergent surgeries in the 4-year study period. 1,398 (75.2%) patients’ operations were performed on the weekdays. The overall post-operative 30-day mortality was 115 (6.2%) and 654 (35.2%) for morbidity. We then found there is a significant different between weekday and weekend mortality (p=0.033). Multivariant analysis was performed and suggested the day of operation (weekday/ weekend) was an independent variable for post-operative mortality. We found that weekends had lower mortality than the weekdays (OR=0.538, 95% C.I.=0.315–0.919; p=0.023). Analysis was further separated into general and specialty surgeries. There was a significant difference between weekday and weekend mortality in general surgery. Day of week was an independent variable for mortality and weekends had lower mortality than the weekdays (OR=0.516, 95% C.I.=0.298–0.893; p=0.018). No significant difference could be observed between weekends and weekdays for morbidity in general surgeries, and morbidity and mortality in specialty surgeries. These results suggested emergency surgery services in the Department of Surgery of PWH were not affected by the “weekend effect” (i.e. mortality increases after operations conducted over the weekends). (Further described in Chapter IV)3) Exploring the effect of hospital volume on outcome of elective major hepatectomy in Hong KongSurgical techniques require years of training and practice and it is considered a crucial determinant in surgical outcomes. It is believed that a higher volume hospital provides more practice experience to surgeons than the lower volume hospitals, thus better surgical service is expected. Currently, it is an unknown in the relationship between hospital-volume and surgical outcome in Hong Kong. We focused on studying the volume-outcome relationship of elective major hepatectomy because the operation is technically demanding and variation of hospital-volume in different departments. Hospital volume categories (high-volume hospital and low-volume hospital – HVH and LVH) were defined by the volume threshold that shows a significant difference in post-operative 30-day mortality. The primary endpoints were 30-day morbidity, intra-operative blood loss, and length of in-hospital stay. We also investigated if service networking provided by the HVHs to LVHs would be beneficial to the surgical performance of the LVHs.Over the 7-year study period (June 2009 – July 2016), 2,389 patients were captured by the SOMIP and the overall post-operative 30-day mortality rate was 2.1% (51 patients). A total of 81 annual hospital-volume entries was included and the median annual hospital-volume of elective major hepatectomy was 18 (range from 1 to 170). The relationship between hospital-volume and 30-day mortality was plotted by scattered-plot and tested with χ² test, and the cutoff volume was 40 major hepatectomy cases per year (OR=2.23, 95% C.I.=1.25–3.98; p=0.005). By using this cut-off volume, high-volume hospitals had consistent mortality rates below 4%. We observed a significant difference in 30-day morbidity rate (p<0.001) and length of hospital stay (p=0.027) but no significant difference for intra-operative blood loss between the high-volume and low-volume hospitals. This means receiving elective major hepatectomy from the HVHs would give better surgical outcomes (morbidity and length of stay) than the LVHs. In addition to this, we also found there was a significant difference on the annual 30- day mortality in the service networking supported LVHs to the LVHs without this support (0% vs. 34.5%; p=0.049). (Further elaborated in Chapter V)4) Predicting risk of post-operative pneumonia after elective operations with Post-operative Pneumonia Risk Indication Score in Elective Surgery (PRISES)Post-operative pneumonia (POP) is one of the major morbidities causing an increased length of in-hospital stay and higher operative mortality. Developing a POP risk score with the risk factors for POP is beneficial to healthcare providers with easier high-risk group identification. There were some POP risk scores developed in different places but the accuracy for application in Hong Kong is questionable. This study utilised the local clinical audit data to develop an institutional POP risk score for elective surgeries – PRISES. This risk calculator was formulated and verified with different sets of internal clinical audit programme data for POP prediction accuracy.The retrospective cohort study included 5,433 elective patients aged from 18 to 100 years. 22 risk factors referenced from the SOMIP analysis were tested using multivariate logistic regression in our study. There were 10 variables found significantly related to POP and included in the PRISES (gender, American Society of Anaesthesiologist (ASA), surgical teams, pulse in surgery, surgical magnitude, operating time, steroid use, functional health dependency, presence of dyspnoea, and potassium range). The Hosmer-Lemeshow test showed that this model fit the samples (p=0.878) and the Area Under the curve of the Receiver Operating Characteristic (AUROC) showed a good fit (p=0.819, 95% C.I.= 0.782–0.856). PRISES consists of 5 cut-off points for the likelihood of POP development. PRISES was verified with another set of cohort data and the model fit (Hosmer-Lemeshow test, p=0.360, AUROC p=0.901, 95% C.I.=0.852–0.950). These results suggested individual patient could use PRISES to predict the probability of developing POP after elective operations. (Further elaborated in Chapter VI)5) Improving surgical quality in a surgical department with close to real-time monitoring system – the Post-procedure Complication Monitoring Programme (PPCMP)The surgeon-led PPCMP keeps track of the patients’ post-operative outcomes. This inhouse surgical audit programme was officially launched in 2010, aimed at cultivating higher accountability of surgeons to the operative outcomes and better quality of surgeries. The platform enables prompt responses from surgeons and department management to unanticipated events and regular service quality assurance. This study describes the setup of the PPCMP and the improvement of operative outcomes after introducing the programme to the Department of Surgery at the PWH.PCMP captured 39,104 patients in total and 43,273 procedure records were conducted during the 7-year-period (2010 – 2016). The 30-day morbidity and 30-day mortality decreased significantly after the first year of PPCMP implementation in 2010 (OR=0.626, p<0.001; OR=0.750, p=0.05), and plateaued in subsequent years. Decreased 30-day morbidity and mortality could be observed in all surgical teams, surgical types and surgical magnitudes. These results suggested the introduction of PPCMP could contribute to the improvement of surgical quality through ongoing patient outcome monitoring mechanisms and educational-based reviewing component. (Further described in Chapter VII)6) Accuracy of Post-procedure Complication Monitoring Programme (PPCMP) on capturing surgical outcomeRecord accuracy in clinical audit project is crucial for judgment making and broadening of its applications. Following the previous study on PPCMP setup and implementation, this study validates the accuracy of PPCMP surgical outcome records by comparing with the SOMIP standard. The hypotheses the accuracy on operative outcome archive of the PPCMP was high. This would strengthen the creditability of adopting the PPCMP audit data for various quality improvement strategies. Record concordance was defined by if the presence or absence of post-operative complication on the particular patient, was listed the same in both PPCMP and SOMIP systems. We conducted logistic regression analysis for the trend of record concordance on post-operative 30-day mortality and morbidity. We also study the characteristics of the discrepant records.A total of 9,416 patients was captured in the SOMIP (reference records) programme in the 4-year study period, and PPCMP captured 9,410 (99.9%) of them. The overall concordance rate of post-operative morbidity was 84.0% and 99.7% for 30-day mortality. In-depth studies found the discrepancy dropped from 2010 to 2011 for both morbidity (p<0.01) and mortality (p<0.05) records, and showed no significant difference in the subsequent years (2011–2014). Sub-group analysis was performed on the accuracy of capturing 30-day morbidity record characteristics. Discrepant records in morbidity were significantly higher in patients of the Colorectal surgery (OR=1.197, p<0.05) and significantly lower in Paediatric Surgery and Paediatric Urology (OR=0.579, p<0.001). In surgical types, the 30-day morbidity discrepant rate in elective operations is lower than emergency operations (OR=0.601, p<0.001). In surgical magnitude, major operations matched better with the SOMIP gold standard than the ultra-major operations (OR=0.710, p<0.001). As the overall discrepancy was low, we conclude that PPCMP recorded patient outcomes in a precise and up-to-standard manner, and is fit to be utilised for future retrospective studies. (Further elaborated in Chapter VIII)ConclusionClinical audit data has proven to be useful in multiple aspects that include retrospective studies, formulate risk prevention model and monitoring the quality of surgical care. We explored with a series of studies using clinical audit. Our results suggested a customised SSI care bundle was an effective tool to lower surgical site infection in elective HBP surgery. Followed by that, our findings discovered service quality of emergent surgeries performed over the weekends is no different from the weekdays. By using clinical audit data, we also found HA hospitals that have a higher volume of elective major hepatectomy is associated with lower 30-day post-operative morbidity and shorter length of hospital stay. This represented an effective use of clinical audit data on health services planning in different hospitals within the same public healthcare system. Then we explored the use of audit programme data to formulate a POP risk model for elective surgery (PRISES). The risk score demonstrated a good POP prediction fit in our setting. Next, we studied on the surgical outcome audit programme that is instituted in our department – PPCMP. Our researches suggested that even with the support of a regional clinical audit project – SOMIP, introducing an in-house audit programme offers multiple benefits. PPCMP supplemented with a direct enhancement of clinical service improvement climate in a surgical department, it enabled prompt responses to adverse clinical phenomena. We concluded that audit programmes, such as PPCMP and SOMIP, facilitate long-term monitoring of surgical quality. Continuous commitment in carrying out clinical audit programmes offers sustainable and efficient surgical quality assurance; strengthen clinical governance in Hong Kong.臨床審核是英國國民保健署(NHS) 管治臨床工作的關鍵部分之一。它是透過分析系統、團隊或組織的表現，將提供優質的住院管理服務。現時臨床審核被多地的醫療機關視為提高醫療質量的重要工具，它的應用亦日趨增加。在香港，香港醫院管理局(醫管局)於2008 起引進了《于衛成效監察計劃》 (SOMIP) ，通過提供年度臨床審核分析數據及質量改進建議，支持並提升公立醫院的外科服務質寰。次年，沙田威爾斯親王醫院(PWH) 的中文大學醫學外科部亦成立了該部門的臨床審核一《手術後併發症監測計劃》 (PPCMP) 。目標以更便於前線外科醫護人員的臨床審核小組加強外部門臨床管治。由於臨床審核所帶動的效益並不顯注，所以不少醫療服務提供者忽視了臨床審核的重要性。這種尚未有清晰了解的互動關係成為了一個研究領域。因此這論文將香港臨床審核進行全面研究，並為在香港實施有系統的臨床審核計劃提供應用和效益層面的參考作用。本論文將對現存於香港的兩個臨床審核計劃- SOMIP 及PPCMP，進行研究。研究分開為三個主體。第一，研究臨床審核所收集的數據，並對預防併發痕針對性工具進行強率分析，同時亦了解並發症和死亡率的出現模式。第三，使用臨床審核計劃數據制定手術後出現併發症的風險評分血統。第三亦是在最後，對香港中文大學外科部的臨床審核一PPCMP 進行深入研究，展示了這個個別部門外科屬隊採用的部門式的臨床審核計劃當中所以應用的結構、工作編制和接勤安排。同時亦針對審核計劃引進以後所帶動的于術表現數據變化進行了解。然後，亦針對研究這個部門式的臨床審核計劃在記銬子術數據的準確性。這將加強PWH 外科臨床審核計劃反映準確數據的可信度，並為其他機構設實臨床審核計劃提供參考基準。本論文總結了臨床審核計劃對外科手術成效及質量改進的重要性。臨床審核計劃需要透過跨團樺的協同努力來維持及實蹺，它將提供多樣化的改進工具以確保香港在外科護理標準方面能夠發揮優質服務水平。Chan, Ho Man.Thesis Ph.D. Chinese University of Hong Kong 2019.Includes bibliographical references (leaves 157-173).Abstracts also in Chinese.Title from PDF title page (viewed on 18, May, 2021).Chan, Ho Man
Revealed likelihood and knightian uncertainty
No full textexpected utility theory;uncertainty;revealed preference
Prototyping and characterising a spatial audio visual aid that models planar structures using 3D sensing
No full textThis thesis presents novel computer vision technologies and spatial audio user interfaces that the author has developed for use in electronic visual aids for vision impaired people. It focuses on the challenges of assisted indoor navigation and object localisation, both active and expanding areas of research with many unsolved problems. The presented research leverages 3D sensing technologies to develop 3D modelling algorithms and spatial sonification techniques that cumulatively result in the development and characterisation of a visual aid prototype for object localisation. Planar surfaces are a common geometrical feature in many man-made environments. The detection of planes could be useful in various applications such as mapping and developing an understanding of the environment. This thesis presents a novel method of allowing a computer system to automatically detect multiple planar surfaces. The proposed algorithm leverages on the RanSaC paradigm to fit plane models to the depth data from an RGB-D sensor. Plane modelling and fitting is performed in inverse depth coordinates which is advantageous in simplifying the error modelling of depth data from the RGB-D sensor. In order to evaluate the performance of the multiple plane detection algorithm, it is first applied to perform egomotion estimation of a moving RGB-D sensor. The proposed egomotion estimation algorithm leverages on the re-detection of planar correspondences between consecutive image frames in order to estimate the movement of the sensor. Next, the plane detection algorithm is used to develop a novel staircase detector. The staircase detection algortihm iteratively detects the multiple planar surfaces of a staircase based on the assumption that staircases consist of multiple evenly spaced steps. The plane detection algorithm is then integrated with a spatial audio user interface to develop an end-to-end visual aid prototype that helps vision impaired users localise objects at close range. The visual aid prototype uses plane detection to narrow the search space for objects in a scene. The location of detected objects are conveyed to the user via spatial audio cues. Characterisation of the prototype is performed by conducting quantitative user trials with both normally sighted individuals who are blindfolded as well as vision impaired individuals. These trials allow for the quantification of human-in-the-loop performance and also reveal interesting trends in user bias and variability. The trials also provide an understanding of the similarities and differences in performance and preference between both normally sighted and vision impaired user groups. Additional user trials are conducted with the use of a simultaneous sonification strategy in an attempt to study how such a communication strategy could be used to improve on the effectiveness and efficiency of existing spatial audio user interfaces. This strategy is based on the hypothesis that human listeners can pay selective attention to relevant streams of audio in the presense of multiple sound sources. Trial results show that simultaneously sonifying multiple sound sources does not adversely impact user performance. Finally, the lessons learned from user trials are applied towards improving the spatial audio user interface. A new spatial audio sonification strategy that spatially distorts the sonified location of objects is introduced. User trials with the new sonification strategy reveal a statistically significant improvement of about 24% on average compared to earlier trials
Mechanistic study of anti-obesity effect of polymethoxyflavones through their bioavailability, biotransformation and interaction with gut microbiota in vivo
No full textPolymethoxyflavones (PMFs) are a unique class of flavonoids that have at least two methoxy groups on the flavone skeleton. About 80 PMFs have been identified from the citrus so far. Among them, tangeretin and nobiletin are the two most prevalent PMFs and widely studied for their biological activities. PMFs have demonstrated a broad spectrum of bioactivities, including neuroprotection, anti-inflammatory, anti-cancer, anti-obesity, anti-atherosclerosis activities. In particular, emerging studies find that PMFs have beneficial effect to maintain the metabolic homeostasis by regulating signals coordinating multiple organs, including the brain, pancreas, liver, adipose tissues, muscles and gastrointestinal (GI) track. However, the underlying mechanisms of their anti-obesity effect still remain unclear. This study aims to explore the anti-obesity activity and biological fate of PMFs in in vivo by investigating their bioavailability, biotransformation and interaction with gut microbiota. Besides, we also have developed delivery systems with the aim of improving PMFs bioavailability. The delivery systems are found to play important roles on the biological fate of PMFs, and thus may influence their bioefficacy in vivo.
In the first part of this work, we have studied the interplay of PMFs and gut microbiota and its implication for obesity control. Using the high fat diet (HFD) induced obese mice, we investigate the modulation effect on gut microbiota by PMFs extracted from the aged citrus peels. PMFs are found to have prebiotic effect by reducing biomarkers of microbial dysbiosis caused by HFD and promoting beneficial bacteria, such as Bifidobacteria and Lactobacillius. PMFs treatment increases the fecal short chain fatty acids (SCFA) production. The metagenomic analysis of the feces shows that the xenobiotics metabolism of the gut microbiota is enhanced by PMFs treatment. Besides, we also study the biotransformation of nobiletin by gut microbiota and in the host organs (in the liver and brain) after 8-week feeding of nobiletin for the HFD-fed mice. The concentration ratio of demethylated metabolites in feces increases dramatically in the feces during the 8 weeks. Both the metagenomics and biotransformation analysis suggest that the long-term metabolic input of PMFs would enable gut microbiota with enhanced biotransformation activity for metabolizing PMFs.
PMFs have shown good anti-obesity activity from recent studies. However, the biological fate of PMFs in vivo remains unclear. The second part of this study is to compare the bioavailability and biotransformation of a typical PMF--nobiletin in the lean- and obese rats. From the excretion study, gut microbiota demonstrates higher extent of demethylation activity than the host, since more di-demethylated nobiletin is found in the feces than the urine. The bioavailability of nobiletin in the lean- and obese- rats is similar, which is about 20%. Higher ratio of demethylated metabolites to nobiletin was found in the feces and plasma in the obese rats than the lean rats after oral administration of 100mg/kg nobiletin. The metabolites profile in the plasma after intravenous injection does not show significant difference for lean- and obese rats. Comparing the results for the oral and injected administration, it suggests that gut microbiota (the microbiome from the lean- and obese rats) plays important role on the biotransformation of PMFs in vivo.
Due to the multiple methoxy groups, PMFs have poor water solubility. We have developed two emulsion systems to enhance the bioavailability of PMFs: the conventional emulsion and organogel-based emulsion. The lecithin-based conventional emulsion with 1% nobiletin has an average droplet size of around 330 nm; has the viscoelastic and gel-like behavior; but could not completely prevent the crystallization of PMFs. According to the pharmacokinetic study using rat model, the conventional emulsion can increase the bioavailable nobiletin and its major metabolite in the blood by about 2 times, as compared to the oil suspension. To further optimize the emulsion formulation, we develop the organogel-based emulsion, which increases the solubility of PMFs by about 3.5 times in the oil phase without crystallization in the room temperature. Furthermore, from the in vitro lipolysis results, the organogel-based emulsion shows better efficiency to improve the bioaccessibility of PMFs, compared to the conventional emulsion.Ph.D.Includes bibliographical reference
利Li yong xuan fu pei yang ji shu ji xiao fen zi zhong xin bian cheng ti xi bao yi biao da yu duo neng xing xiang guan ji yin zhi yan jiu
No full textPh.D.The concept of stem cells and tissue engineering have been regarded as the future of regenerative medicine. Stem cell is the most crucial building block and starting material. These cells could be obtained from the embryos, various parts of our body or generated from somatic cells that have been reprogramed and induced to become pluripotent stem cells (iPSC). To date, research have been focused on reducing the use of exogenous factors and also increasing the efficiency of generating iPSC, in order to render stem cells safe to use and cost effective to produce. Small chemical molecules have now been applied in various stem cell production protocols to induce somatic cell de-differentiation and promote their reprogramming into stem cells.In this study, we examined the relationship between suspension spheroid fibroblast culture and the reprogramming of these fibroblasts into stem cells. There is now increasing evidence that show a variety of somatic cells could be induced to express pluripotency stem cell markers simply by culturing these cells in the form of spheroids. The most convincing results to date are reports that adult and cancer stem cells could acquire enhanced differentiation capacities when these cells are cultured as spheroids.We investigated this phenomenon further by first developing and standardizing a protocol for generating spheroids from fibroblasts and human umbilical cord perivascular (HUCPV) cells. We demonstrated for the first time that when human fibroblasts are manipulated to become a spheroid in vitro, they are induced to express pluripotency-associated gene, OCT4, SOX2 and NANOG. These hallmark genes are expressed when somatic cells are reprogrammed to become pluripotent stem cells. We also observed that expression of genes associated with mesenchymal-to-epithelial transition. We determined that the addition of a small molecule, named Reversine, could exert a synergistic effect with the fibroblast spheroids to enhance changes in gene expression. The combined used of spheroid culture and Reversine treatment could induce fibroblasts and HUCPV cells to express pluripotency-associated genes. The transcription profile of these genes resembled that of somatic cells being reprogrammed as stem cells.We then profiled and compared the transcriptomes of human fibroblasts grown as monolayer and spheroid cultures, as well as after Reversine treatments. We identified a high number genes, ranging from 600-3300, which were differentially expressed in fibroblasts during spheroid formation and with/without Reversine treatment compared with normal fibroblasts monolayer cultures. These differentially expressed genes were enriched for pluripotent-associated cell signalling pathways and modelling of the extracellular matrix (ECM) associated with the maintenance of pluripotency. By analysis and validation, we determined that spheroid formation with/without Reversine treatment increased the activity of the PI3K/AKT pathway, expression of upstream cytokines (LIF, LIFR) and downstream effectors (TBX3). This increase in bio-activity may in turn induce the expression of the pluripotency markers. We propose that changes in three variables during the formation of the spheroids (namely (1) hypoxia, (2) secretome of fibroblasts and (3) ECM remodelling) were responsible for inducing the expression of the pluripotent genes. Using MALDI-TOF/TOF analysis, we identified several ECM proteins that were down-regulated in the fibroblast spheroids, including collagen type I, fibronectin and thrombospondin 1. Importantly, it has been reported that thrombospondin 1 is normally suppressed by the PI3K/AKT signalling which inhibits the expression of pluripotent genes.In conclusion, we have demonstrated that spheroid culture plus Reversine treatment can induce human fibroblast to express pluripotent genes and deduced the possible mechanisms involved.組織工程和再生醫學被認為是新一代組織修復與器官移植的研究方向，其中幹細胞是最重要的原材料。除了從胚胎和身體獲得活的胚胎或成體幹細胞，將體細胞重編程為多能幹細胞是現時負有最大期望的途徑。為了增加幹細胞重編程在臨床應用的安全性和成本效益，科學家正不斷地研究減少使用外生因素並提高重編程效率的實驗方法。現時，合成小分子已被應用在誘導去分化和促進重編程的各種實驗中，同時取代使用病毒或會與基因組整合的質粒。另一方面，細胞懸浮球狀體培養方法與幹細胞重編程之間的關係曾被提出但沒有仔細研究。這個假設是通過積累各種細胞在培養為球狀體時獲得多能幹細胞表型的證據來支持的。其中最具說服力的實驗結果是懸浮球狀體培養方法增強了成體和癌細胞在球狀體培養中的分化能力。為了測試這個假設，我們標準化了人和小鼠成纖維細胞以及人臍帶血管周皮幹細胞的球狀體培養方案。我們首次表明了當人類成纖維細胞在體外形成球狀體時，會過度表達多能性以及重編程的標誌基因，包括幹細胞和間充質--上皮轉化過程會表達的基因。我們還發現，添加名為Reversine的小分子可以在基因表達變化方面與球狀體形成發揮協同作用。球狀體培養和Reversine的組合可誘導上述三種細胞類型表達多能性相關基因，而其表達譜類似於幹細胞重編程。然後我們針對人成纖維細胞在生長為單層和球狀體或添加了Reversine的情況下分析和比較它們的轉錄組。相對於正常單層培養，人成纖維細胞在生長為球狀體或添加了Reversine時有高達600-3300的差異表達基因。這些基因被顯著且反复地富集於與細胞多能性相關的細胞信號通路及外基質建模。我們確定球狀體形成會增加PI3K / AKT通路的活性以及上游細胞因子LIF，LIFR和下游效應子TBX3的表達，最後引致多能性標記基因表達的上調。基於實驗結果和掃描電子顯微鏡下細胞的觀察，我們推測細胞在球狀體形成中的三個變量，即缺氧環境，成纖維細胞的分泌和外基質重塑，是基因表達變化的原因。我們發現缺氧因素和球狀體的細胞分泌物質對人成纖維細胞沒有影響，但細胞球狀體的外基質組成可影響基因表達。使用蛋白質質譜法，我們發現幾種外基質蛋白在成纖維細胞球狀體中表達較低，包括膠原I型(Collagen Type I)，纖連蛋白(Fibronectin) 和血小板反應蛋-1(thrombospondin 1)，其中血小板反應蛋-1曾被證實能抑制多能性基因的表達，同時被PI3K / AKT途徑抑制。在本研究中，我們證明球狀體培養和Reversine對多種細胞類型有很大的影響，能將其表型和轉錄組分佈轉移到近似於幹細胞重編程時的狀態。這些發現可以應用於未來的幹細胞研究和重編程方案中。本研究還對三維培養方法和培養微環境在幹細胞重編程中的重要性和益處的提供了新的見解。Lo, Lok Man.Thesis Ph.D. Chinese University of Hong Kong 2017.Includes bibliographical references (leaves 145-162).Abstracts also in Chinese.Title from PDF title page (viewed on …).Lo, Lok Man
Regional anaesthesia for caesarean section in severe preeclampsia: spinal anaesthesia is the preferred choice
No full textPart of the Portfolio Thesis by Geoffrey H. Sharwood-Smith: The inferior vena caval compression theory of hypotension in obstetric spinal anaesthesia: studies in normal and preeclamptic pregnancy, a literature review and revision of fundamental concepts, available at http://hdl.handle.net/10023/1815Standard textbooks advocate epidural rather than spinal anaesthesia for caesarean section in severe preeclampsia. The basis for this recommendation is the theoretical risk of severe hypotension but no published scientific studies have been identified to support this assertion. We therefore designed a prospective study to compare spinal versus epidural anaesthesia in severely pre-eclamptic patients requiring hypotensive therapy. Following ethics committee approval, 28 women with preeclampsia requiring hypotensive medication who were scheduled for urgent (not emergency) or elective caesarean section consented to receive epidural or spinal anaesthesia by random assignment. Seven patients were excluded due to protocol violations. Four of these were in the epidural group of which two were excluded due to inadequate analgesia. No spinal patient was excluded because of inadequate analgesia. Mean ephedrine dosage was 5.2 mg (range 0–24 mg) in the spinal group and 6.3 mg (range 0–27 mg) in the epidural group. Six of the 11 patients in the spinal group required no ephedrine as did five of 10 in the epidural group. One patient in the spinal group suffered from mild intraoperative pain. By contrast in the epidural group three patients had mild pain and four others had pain severe enough to warrant intraoperative analgesia. There were no differences in neonatal outcomes. These findings support recent studies suggesting the safety and efficacy of spinal anaesthesia in this group of patients.Publisher PD
The inferior vena caval compression theory of hypotension in obstetric spinal anaesthesia: studies in normal and preeclamptic pregnancy, a literature review and revision of fundamental concepts
No full textFull metadata records and copyright statements for publications contained in this portfolio thesis are available at the identifiers listedThree clinical investigations together with a combined editorial and review of the cardiovascular physiology
of spinal anaesthesia in normal and preeclamptic pregnancy form the basis of a thesis to be submitted for the
degree of Doctor of Medicine at the University of St Andrews. First, the longstanding consensus that spinal
anaesthesia could cause severe hypotension in severe preeclampsia was examined using three approaches.
The doses of ephedrine required to maintain systolic blood pressure above predetermined limits were first
compared in spinal versus epidural anaesthesia. The doses of ephedrine required were then similarly studied
during spinal anaesthesia in preeclamptic versus normal control subjects. The principal outcome of these
studies, that preeclamptic patients were resistant to hypotension after a spinal anaesthetic, was then further
investigated by studying pulse transit time (PTT) changes in normal versus preeclamptic pregnancy. PTT
was explored both as beat-to-beat monitor of cardiovascular function and also as an indicator of changes in
arterial stiffness. The cardiovascular physiology of obstetric spinal anaesthesia was then reviewed in the light
of the three clinical investigations, developments in reproductive vascular biology and the regulation of
venous capacitance. It is argued that the theory of a role for vena caval compression as the single cause of
spinal anaesthetic induced hypotension in obstetrics should be revised
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