Thesis (M.B.A.)--University of Hong Kong, 1998. / Includes bibliographical references (leaf 74-75).

published_or_final_version / Nursing Studies / Master / Master of Nursing

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

Thesis (M.S.)--University of Florida, 2004. / Title from title page of source document. Document formatted into pages; contains 65 pages. Includes vita. Includes bibliographical references.

published_or_final_version / Business Administration / Master / Master of Business Administration

Introduction. Safe closure of gastric luminal defects remains a big challenge for development of gastric endoscopic surgery. The aims of this thesis are to assess the effect and efficiency of Eagle Claw VIII (endoscopic suturing device)and adipose tissue-derived mesenchymal stem cells (ADMSCs) for closure and enhancing healing of gastric luminal defects. / Methods and Results. 1. Endoscopic suturing is superior to endoclips for closure of gastrotomy after NOTES. A 2cm linear incision on the body of porcine stomach was closed by hand suturing, Eagle Claw VIII or endoclips, respectively (n=17 for each group). The results indicated that all gastrotomies were successfully closed. Closure time was significantly longer in Eagle Claw VIII group. Bursting pressure of gastrotomies for Eagle Claw VIII was significantly higher than endoclips, but lower than hand suturing. Besides, both Eagle Claw VIII and endoclip closure encountered significantly technical challenges. This study suggested that Eagle Claw VIII had potential for endoscopic closure of gastrotomies, but need further refinement. / 2. ADMSCs for Acceleration of Healing of Sutured Gastric Perforation(SGP). ADMSCs were isolated and expanded in vitro, and characterized by stromal differentiations and cell surface markers. A 2cm SGP was produced on gastric body of rats. 5×10⁶ ADMSCs were transplanted into SGP by local injection (LI-ADMSCs) or topical spraying (TS-ADMSCs). Healing of SGP was assessed. LI-ADMCs significantly decreased peritoneal adhesion and wound dehiscence, and increased bursting pressure of SGP, when comparing to other experimental groups. Histologic analysis indicated that SGPs in LI-ADMSCs group had more re-epithelialization and collagen regeneration, and less inflammation. Expression of TGF-β1 was up-regulated, while IL-6 was down-regulated in LI-ADMSCs group, when comparing to fibrin and control groups. This study suggested that local injection of ADMSCs is an effective approach for accelerating the healing of SGP. / 3. Promoting Effect of ADMSCs on Healing of Gastric Ulcer is abrogated by NSAIDs. Gastric ulcer model in rats was successfully produced by using 70% acetic acid. A total of 1×10⁷ ADMSCs was locally injected into ulcer lesion. Ulcer area was measured at different time points. Therapeutic potentialof ADMSCs was assessed when NSAIDs was simultaneously administrated. The results demonstrated that ADMSCs significantly decreased ulcer area. Histologic assessment indicated that ADMSCs increased re-epithelialization, angiogenesis and collagen deposition, and suppressed inflammation. Transplanted ADMSCs homed into gastric ulcer lesion and differentiated into endothelial and smooth muscle cells. In addition, ADMSCs treatment increased the gene expressions for wound healing, and activated COX-2-PGE₂ and Erk1/2-MAPK signaling pathways. Repeated administration of Indomethacin reduced cell proliferation and angiogenesis, and eliminated ADMSCs-induced ulcer healing on day 10. The results suggested that ADMSCs promoted the healing of peptic ulcer, which is eliminated by NSAIDs. / Conclusions. Endoscopic suturing by Eagle Claw VIII is feasible for closure of gastrotomy, when comparing to endoclips. ADMSC promotes the healing of gastric luminal defects including SGP and ulcer. The promoting effect of ADMSC is PGE₂-dependent, and attenuated by NSAIDs. These evidences implied that combined use of endoscopic suturing and ADMSCs is a helpful approach for safe closure of gastrotomy and gastric perforation. / 引言：胃傷口癒合是胃消化內鏡手術發展的障礙之壹。本課題之目的是評價和探索Eagle Claw VIII和脂肪幹細胞(ADMSCs)縫合和促進胃內傷口癒合的效果和作用。 / 方法和結果：1. 內鏡縫合器Eagle Claw VIII閉合經胃自然腔道手術後傷口的效果評價體外豬胃體上造2cm的胃傷口模型，使用手工縫合、內鏡下Eagle Claw VIII縫合或內鏡夾閉合胃傷口；每組17個樣本。本研究提示所有胃傷口均成功閉合。Eagle Claw VIII縫合胃傷口時間顯著長於其他兩組的閉合時間。Eagle Claw VIII縫合的胃傷口破裂壓顯著高於內鏡夾閉組，但是明顯低於手工縫合組。此外，內鏡縫合和夾閉都面臨較大的技術難度。本研究提示Eagle Claw VIII有臨床運用的潛在價值，但需要進壹步改進。 / 2. 局部移植脂肪幹細胞促進胃穿孔癒合的實驗性研究：建立大鼠2cm胃體穿孔模型，局部註射或傷口表面塗抹法移植ADMSCs，觀察胃傷口癒合情況。局部註射移植ADMSCs顯著減輕胃傷口粘連和裂開發生率，增加胃傷口破裂壓。組織學分析提示ADMSCs治療促進傷口上皮和肉芽組織再生，抑制炎癥反應。此外，局部註射ADMSCs增加TGF-β1抑制IL-6表達。本研究提示局部註射移植ADMSCs是促進胃穿孔傷口癒合的有效方法。 / 3. 局部移植脂肪幹細胞促進胃饋瘍癒合的實驗性研究：使用70%醋酸建立大鼠胃體饋瘍模型；饋瘍病竈內局部註射移植1×107 ADMSCs。研究提示第10和15天ADMSCs顯著減小饋瘍面積。組織學研究提示ADMSCs增加饋瘍傷口上皮和血管再生，促進膠原蛋白分泌和抑制炎癥反應。移植的ADMSCs能夠在饋瘍病竈內成活，並分化成血管內皮細胞和平滑肌細胞。ADMSCs顯著提高促傷口癒合相關基因表達水準。此外，ADMSCs啟動COX-2-PGE2和Erk1/2-MAPK信號通路。第10天，和對照組相比，引哚美辛/ADMSCs組潰瘍病竈內細胞增殖和血管再生顯著降低、饋瘍癒合延遲。本研究提示脂ADMSCs促進胃饋瘍癒合；非甾體抗炎藥顯著減弱ADMSCs的促胃饋瘍癒合作用。 / 結論：與內鏡夾閉相比，Eagle Claw VIII內鏡縫合胃創口有可行性。ADMSCs促進胃穿孔和饋瘍癒合，且依賴於前列腺素E2；引哚美辛抑制前列腺素E2合成從而抑制ADMSCs促胃組織癒合之效能。本研究提示聯合使用內鏡縫合器和ADMSCs是促進胃傷口癒合的潛在有效方法。 / Thesis Ph.D. Chinese University of Hong Kong 2014. / Includes bibliographical references (leaves 152-162). / Abstracts also in Chinese. / Title from PDF title page (viewed on 11, October, 2016). / Liu, Liu. / 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.

We propose a computer integrated endoscopic simulator for training in upper endoscopy as a low-cost alternative to the traditional training methods and virtual reality simulators. The use of a real endoscope in conjunction with our simulator and computer system in an actual operating room setup makes the training environment similar to a real procedure. Endoscopic surgery is the performance of surgery through a small incision with the aid of special medical equipment called a flexible endoscope. The advantage of this technique over open surgery is that there is significantly less operative trauma, resulting in less pain and a shorter recovery time. Side effects of the surgery, such as the risk of infection, are also reduced. While endoscopy procedure has tremendous benefits, surgeons require considerable practice and time to develop competency. Traditionally, the procedure has been taught at the expense of patient comfort and safety, in other words, gastroenterology training fellows have performed the surgery under the supervision of physicians. Patients who undergo the endoscopies performed by fellows, particularly early in the training period, have been more likely to suffer more discomfort and prolonged procedures. In this study, we introduce a new type of simulator which combines the use of mechanical model and computer system as an additional or low-cost alternative for training in upper endoscopy. Our approach is to integrate a computer system with a realistic mechanical model to create a computer-based simulator for upper endoscopy training. The simulator will cover the basics of flexible endoscopy and teach a trainee the skills required to perform upper endoscopy. The mechanical training model with a sensor system that simulates a human upper gastrointestinal tract, including pathologies such as ulcers and polyps, will be built and integrated with computer software. The software offers the following functions: provides help to the trainee, provides curriculum-required learning tasks, and assesses the performance and diagnostic skills. Due to the optical nature of an endoscopic lens, the obtained image suffers from a barrel-type spatial distortion, which results in an inconsistent measurement of object size and distance. Our distortion correction system with automatic calibration, based on least squares estimation, offers a better perception of size and distance from the endoscopic images. In order to examine the endoscopic maneuvering skills of the trainee, the automatic evaluation system is created. The system uses images from the exam procedure to verify the trainee skills. We use Support Vector Machine to classify endoscopic images of different regions in upper gastrointestinal tract. The experimental results on the distortion correction and image classification are reported. Simulator validation survey result from gastroenterology surgeons and fellows is included in this dissertation. A recommendation for further study is also enclosed.

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002. / Includes bibliographical references (leaves 106-108). Also available in electronic version. Access restricted to campus users.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2006. / Includes bibliographical references (leaves 112-116). Also available in electronic version.

Background: Coronary Artery Bypass Grafting (CABG) surgery is one of the most commonly performed surgical procedures to improve the symptoms of coronary artery disease. The Long Saphenous Vein (LSV) is typically used as a graft to bypass the blocked coronary arteries. The traditional way of harvesting the LSV is to make a long skin incision in the patient's leg. This technique has a high rate of incidence of wound complications and postoperative pain and poorer patient satisfaction. Endoscopic Vein Harvesting (EVH) techniques, introduced more than a decade ago, reduce these complications and improve quality of life. Findings regarding the safety and efficacy of EVH techniques and the quality of the vessel harvested by this technique are contradictory. Adoption of EVH techniques is still inconsistent globally and it is not completely accepted by all cardiac centres. Many studies are available in the literature measuring either histological outcome or clinical outcome in relation to different harvesting techniques. However, there remains no definitive randomised data available directly correlating harvesting-induced vein damage with clinical outcome. The aim of this Vein Integrity and Clinical Outcome (VICO) randomised trial was designed to assess the direct relationship between the histological damage caused during different methods of vein harvesting and clinical outcome post coronary artery bypass surgery. Methods: 100 patients were randomised in each group: Group 1 consists of closed tunnel CO2 endoscopic vein harvesting (EVH) (CT-EVH) and Group 2 consists of open tunnel CO2 EVH (OT-EVH) with the control Group 3 consists of standard open vein harvesting (OVH) with a total of 300 patients in this study. All the veins were harvested by an experienced practitioner who has performed &gt;2000 OVH and &gt;250 EVH. 1cm x 3 segments from three different parts of the vein were obtained for all patients (n=900). The histological levels of damage (endothelial and muscular layers) of the harvested vein and post clinical outcome for Major Adverse Cardiac Events (MACE) were measured using validated measuring tools. Health economic (cost effectiveness, EQ-5D) and health-related quality of life (SF-36) data were also recorded to assess the impact of these surgical techniques. Results: The level of endothelial disruption was greatest in the OT-EVH group in the proximal, distal and random samples (all p < 0.001). Internal muscle migration was greatest in OT-EVH compared to the other groups for proximal, distal and random samples (all p < 0.001). Smooth muscle circular layer detachment was observed on a much greater scale in the endoscopic groups compared to OVH in proximal (p=0.008), distal (p < 0.001) and random (p=0.001). Smooth muscle longitudinal layer detachment was consistent between groups in proximal (p=0.113) and distal (p=0.380) samples but was greater in endoscopic groups compared to OVH (p=0.012). Secondary clinical outcomes demonstrated no significant differences in composite MACE scores at 3, 6, 12, 18 and 24 months. The quality adjusted life in years (QALYs) gain per patient was: 0.11 (p < 0.001) for closed tunnel CO2 EVH and 0.07 (p=0.003) for open tunnel CO2 EVH compared with open vein harvesting. The likelihood of being cost-effective, at a pre-defined threshold of £20,000 per QALYs gained was: 75% for closed tunnel EVH, 19% for open tunnel EVH and 6% for open vein harvesting. Conclusion: In this study, open vein harvesting was associated with better preservation of vein layers in non-distended proximal samples than endoscopic vein harvesting. Both EVH groups displayed some degree of histological damage; OT-EVH was associated with more endothelial disruption. Clinical outcomes suggest that histological findings do not directly contribute to MACE outcomes. Gains in health status were observed and cost-effectiveness was better with CT-EVH compared with the other two surgical techniques. These results suggest that EVH can be utilised safely, but with careful selection of patients.