Thesis (M.S.)--University of Wisconsin. School of Nursing, 1975. / eContent provider-neutral record in process. Description based on print version record.

Thesis (M.S.)--University of Wisconsin-Madison, 1993. / Typescript. Appendix B in Chinese. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 70-78).

Thesis (M.S.)--Catholic University of America. / Includes bibliographical references.

Thesis (Ph. D.)--Dept. of Psychology. University of Missouri--Kansas City, 2005. / "A dissertation in psychology." Advisor: C. Keith Haddock. Typescript. Vita. Title from "catalog record" of the print edition Description based on contents viewed June 20, 2006. Includes bibliographical references (leaves 91-113). Online version of the print edition.

Thesis (MScIng)--University of Stellenbosch, 2005. / Bibliography. Also available via the Internet.

Thesis (Ph.D.)--York University, 2004. Graduate Programme in Biology. / Typescript. Includes bibliographical references. Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNQ99153

One of the major achievements in cardiac surgery over the past 30 years has been the ability to replace severely diseased heart valves with prosthetic ones. The option of using prosthetic heart valves for the treatment of valvular diseases has improved and prolonged many lives. This is reflected in around 120,000 heart valve replacement operations carried out every year in North America alone to correct the cardiovascular problems of stenosis, insufficiency, regurgitation, etc. The development of artificial heart valves depends on reliable knowledge of the hemodynamic performance and physiology of the cardiovascular system in addition to a sound understanding, at the fundamental level, of the associated fluid mechanics. It is evident from the literature review that noninvasive measurements in a confined area of complex transient geometry, providing critical information relating to valve performance, are indeed scarce. This thesis presents results of an extensive test program aimed at measuring turbulence stresses, steady and transient velocity profiles and their decay downstream of the mitral valve. Three mechanical tilting disc-type heart valves (Björk-Shiley convexo- concave, Björk-Shiley monostrut, and Bicer-Val) and two biological tissue valves (Hancock II and Carpentier-Edwards supraannular) are studied. The investigation was carried out using a sophisticated and versatile cardiac simulator in conjunction with a highly sensitive, noninvasive, two-component three-beam laser doppler anemometer system. The study covers both the steady (valve fully open) and pulsatile (resting heart rate) flow conditions. The continuous monitoring of the parametric time histories revealed useful details of the complex flow as well as helped establish location and timing of the peak parameter values. In addition, orientation experiments are conducted on the mechanical valves in an attempt to reduce stresses by altering the position of the major orifice. The experiments suggest correlation between high stresses and orientation. Based on the the data, the following general conclusions can be made: (i) Hemodynamic test results should be presented in nondimensional form to render them independent of test facilities, flow velocities, size of models, etc. This would facilitate comparison of results by different investigators, using different facilities and test conditions. (ii) The valves tested showed very disturbed flow fields which generated high turbulent stresses presenting a possibility of thromboembolism and, perhaps, haemolysis. (iii) Implantation orientation of the valve significantly affect the mechanical prostheses flow field. The single vortex formation in the posterior orientation results in a reduction in stresses compared to the anterior configuration. (iv) The present results together with the earlier information on pressure drop and regurgitation provide a comprehensive and organized picture of the valve performance. (v) The information is fundamental to the improvement in valve design, and development of guidelines for test methodology and acceptable performance criteria for marketing of the valves. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

Acute and chronic rejection continue to be the most important problems in maintaining a functioning organ allograft. Despite advances in immunosuppression, organs are still damaged or destroyed by the recipient's immune system. In order to protect the transplanted organ it is necessary to overwhelm the host's immune system and thus expose the host to the complications of invasion from fungi, bacteria, protazoa, reduction in oncologic surveillance, and reduction of stem cell production. Donor specific immunosuppression would provide graft protection and allow maintenance of the host's immunologic competence. Graft enhancement has been described for many years. Current practice uses this principle by pretransfusing prospective kidney transplant recipients with type specific blood. Previous work has supported the concept that this clinical effort can be produced by certain cells in the blood, specifically, lymphocytes. To study the effects of preimmunization with T or B lymphocytes and platelets in a rat heterotopic heart transplant model, the following experiments were performed. Experiment 1: The effect of pretransplant immunization with lxlO7 donor specific T cells or B cells showed that T cells have little affect on rejection of heterotopic heart allograft and B cells caused prolongation of graft function. This effect is species specific and not due to a pure anti-idiotype phenomenon. Experiment 2: The effect of heating the purified T and B cells at 56°C for 30 minutes is known to denature the presenting protein antigens on the cell membranes without destroying the cell membrane. After pretransplant immunization, seven days prior to heterotopic heart transplant in the rat model, the previously observed prolongation of graft survival after nonheated B cell immunization was still present but not as marked. Experiment 4: The effect of pretransplant immunization of donor specific T and B cells treated by heating to 85°C for 10 minutes followed by heterotopic heart graft showed that there was a significant prolongation of the engrafted heart following immunization with the denatured B cells. Cellular proteins are denatured by this pretreatment but polysaccharides are not. Experiment 5: The effect of pretransplant immunization with purified donor specific platelets followed by heterotopic heart rat transplant showed no prolongation or shortening of graft survival. It is concluded that, in the heterotopic rat heart transplant model, immunization with purified T cells 7 days prior to transplant has little effect on rejection. When B cells are immunized in the same way, graft survival is prolonged. If the cells are heated to 56°C for 30 minutes this effect is reduced but not eliminated. This effect indicates that denaturation of protein HLA antigens on the presenting cell surface reduces the enhancing effect of the intact antigens on B cells. By denaturing, the presenting B cell protein graft enhancement is still present, suggesting the phenomenon of graft enhancement is not totally dependent on protein antigens but may have a contribution from mucopolysaccharides or other carbohydrates. Donor specific purified platelet pretransplant immunizations produced no statistically significant prolongation of either PV6 or F₁ heart grafts. This observation is consistent with the findings that purified T cell immunization do not produce graft enhancement. / Surgery, Department of / Medicine, Faculty of / Graduate

This study evaluates the outcomes of a hospital-based cardiac rehabilitation program designed to deliver the first phase of cardiac rehabilitation services at home. The program was established in a community hospital in 1985, operating under the administration of the hospital's Medical Day Centre. Patients suffering from acute myocardial infarction (MI) are referred to the program by their physician and receive services from a cardiac nurse specialist immediately upon discharge. The services continue for a period of 6 weeks. The outcomes of importance in the study are the effects of the program on hospital services in the initial 10 month period and on patient's health related behaviour 3 months post infarction. Results of the study indicate that program goals were achieved during the initial 10 months of the study. Physicians referred 92% of the eligible patients and the average length of stay (ALOS) in hospital was satisfactorily reduced. For patients with uncomplicated MI the ALOS was 8.6 days by the tenth month. At 3 month follow up, patients reported significant improvements over their pre infarction health related behaviour. There were significant increases in the frequency of light exercise (p<-0005), in the regular use of low fat dairy products (p=.0003) and in the practice of restricting calories (p=.003) while significant decreases were reported in the frequency of consuming fried foods (p<.0005), salted foods (p<.0005) and rich foods (p<.005) and in the regular use of table salt (p=.00003). Smoking cessation was reported by 50% of the smokers at follow up. Patients reported a high level of satisfaction with the program, describing the service as well timed, informative, practical and valuable in restoring their self confidence. While these results were satisfactory with regards to the program goals, the evaluation was based on a single group design and further investigation is desirable with comparisons between hospitals and between patients with and without exposure to the program. / Medicine, Faculty of / Population and Public Health (SPPH), School of / Graduate

Objectives A substantial number of patients with severe tricuspid regurgitation (TR) and congestive heart failure (CHF) are medically managed without undergoing corrective surgery. We sought to assess the characteristics and outcomes of CHF patients who underwent tricuspid valve surgery (TVS), compared with those who did not. Methods Retrospective observational study involving 2556 consecutive patients with severe TR from the Cleveland Clinic Echocardiographic Database. Cardiac transplant patients or those without CHF were excluded. Survival difference between patients who were medically managed versus those who underwent TVS was compared using Kaplan-Meier survival curves. Multivariate analysis was performed to identify variables associated with poor outcomes. Results Among a total of 534 patients with severe TR and CHF, only 55 (10.3%) patients underwent TVS. Among the non-surgical patients (n=479), 30% (n=143) had an identifiable indication for TVS. At 38 months, patients who underwent TVS had better survival than those who were medically managed (62% vs 35%; p<0.001). On multivariate analysis, advancing age (HR: 1.23; 95% CI 1.12 to 1.35 per 10-year increase in age), moderate (HR: 1.39; 95% CI 1.01 to 1.90) and severe (HR: 2; 95% CI 1.40 to 2.80) right ventricular dysfunction were associated with higher mortality. TVS was associated with lower mortality (HR: 0.44; 95% CI 0.27 to 0.71). Conclusion Although corrective TVS is associated with better outcomes in patients with severe TR and CHF, a substantial number of them continue to be medically managed. However, since the reasons for patients not being referred to surgery could not be ascertained, further randomised studies are needed to validate our findings before clinicians can consider surgical referral for these patients. / Revisión por pares