Tsang Kam Sze, Kent. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1992. / Includes bibliographical references (leaves 155-174). / Abstract --- p.i / Acknowledgements --- p.v / List of Abbreviations --- p.viii / Table of Contents --- p.x / List of Figures --- p.xvi / List of Tables --- p.ixx / Chapter Chapter 1. --- Introduction --- p.1 / Chapter 1.1. --- Idiotype Network --- p.2 / Chapter 1.2. --- Anti-idiotype Classification --- p.8 / Chapter 1.3. --- Blood Transfusion Effect --- p.11 / Chapter 1.4. --- Transfusion Protocol --- p.12 / Chapter 1.5. --- Mechanism of Beneficial Transfusion Effect --- p.15 / Chapter 1.5.1. --- Donor Selection --- p.15 / Chapter 1.5.2. --- Clonal Deletion --- p.16 / Chapter 1.5.3. --- Suppressor Cells Induction --- p.18 / Chapter 1.5.4. --- Prostaglandins Mediation --- p.19 / Chapter 1.5.5. --- Mixed Chimerism Motivation --- p.20 / Chapter 1.5.6. --- Fc-receptor Blocking Antibodies Stimulation --- p.22 / Chapter 1.5.7. --- Anti-idiotypic Antibodies Instigation --- p.23 / Chapter 1.6. --- Study Aims --- p.25 / Chapter 1.7. --- Technical Strategy --- p.26 / Chapter Chapter 2. --- Materials and Methods --- p.30 / Chapter 2.1. --- Materials --- p.31 / Chapter 2.1.1. --- Patient Population --- p.31 / Chapter 2.1.2. --- Normal Control Group --- p.31 / Chapter 2.1.3. --- Serum Samples --- p.32 / Chapter 2.1.4. --- Additional Specimens --- p.32 / Chapter 2.1.5. --- Chemicals --- p.32 / Chapter 2.1.6. --- Antisera --- p.34 / Chapter 2.1.7. --- Buffers --- p.35 / Chapter 2.1.8. --- Consumables --- p.38 / Chapter 2.1.9. --- Apparatus and Equipment --- p.39 / Chapter 2.2. --- Methods --- p.40 / Chapter 2.2.1. --- Purification of Human Polyclonal Anti-HLA Antisera --- p.40 / Chapter 2.2.1.1. --- Affinity Chromatography --- p.41 / Chapter 2.2.1.2. --- Dialysis --- p.41 / Chapter 2.2.1.3. --- Concentration --- p.42 / Chapter 2.2.1.4. --- Quantitation --- p.42 / Chapter 2.2.2. --- Generation of F(ab')2 fragments from the Purified Human Anti-HLA Antibodies --- p.42 / Chapter 2.2.2.1. --- Buffer Exchange --- p.43 / Chapter 2.2.2.2. --- Pepsin Digestion --- p.43 / Chapter 2.2.2.3. --- Purification of (ab')2、 --- p.43 / Chapter 2.2.3. --- Enzyme-Linked Immunosorbent Assay for anti-Idiotypes against anti-HLA antibodies --- p.44 / Chapter 2.2.3.1. --- Optimization --- p.44 / Chapter 2.2.3.2. --- Quality Control --- p.45 / Chapter 2.2.3.2.1. --- F(ab')2 Specificity --- p.45 / Chapter 2.2.3.2.2. --- Fc Contamination --- p.46 / Chapter 2.2.3.2.3. --- Precision Test --- p.47 / Chapter 2.2.4. --- Anti-Casein Interference --- p.47 / Chapter 2.2.5. --- Test Protocol --- p.48 / Chapter 2.3. --- Statistical Analysis --- p.48 / Chapter Chapter 3. --- Purification of Anti-HLA IgG and F(ab')2 --- p.50 / Chapter 3.1. --- Immunoglobulin Concentration --- p.51 / Chapter 3.2. --- F(ab')2 Specificity --- p.51 / Chapter 3.3. --- Fc-fragments Contamination --- p.53 / Chapter 3.4. --- Discussion --- p.56 / Chapter Chapter 4. --- ELISA Optimization --- p.57 / Chapter 4.1. --- Coating F(ab')2 Quantitation --- p.58 / Chapter 4.2. --- Blocking and Diluting Agent Concentration --- p.61 / Chapter 4.3. --- Serum Analyte Dilution --- p.61 / Chapter 4.4. --- Conjugated Detector Antibody Titration --- p.64 / Chapter 4.5. --- Discussion --- p.66 / Chapter Chapter 5. --- Quality Control --- p.70 / Chapter 5.1. --- Avoidance of Prozone Phenomenon --- p.71 / Chapter 5.2. --- Inter-assay and Intra-assay Precision --- p.71 / Chapter 5.3. --- Discussion --- p.74 / Chapter Chapter 6. --- Adjustment of Anti-casein Interference --- p.77 / Chapter 6.1. --- Casein Allergy --- p.78 / Chapter 6.2. --- Prevalence of Anti-casein --- p.80 / Chapter 6.3. --- Discussion --- p.81 / Chapter Chapter 7. --- Prevalence of Anti-idiotypic Antibodies --- p.86 / Chapter 7.1. --- Formation Kinetics --- p.87 / Chapter 7.2. --- Occurrence in Transplant Patients --- p.87 / Chapter 7.3. --- Transfusion Effect --- p.101 / Chapter 7.3.1. --- Comparison between Transfused Transplant Patients and Normal Controls --- p.103 / Chapter 7.3.2. --- Comparison between Transfused Transplant Patients and Non-transfused Transplant Patients --- p.116 / Chapter 7.3.3. --- Association with Graft Survival --- p.117 / Chapter 7.4. --- Discussion --- p.128 / Chapter Chapter 8. --- Correlation of Transfusion with the Outcome of Transplant --- p.137 / Chapter 8.1. --- Rejection Episode --- p.138 / Chapter 8.2. --- Graft Survival --- p.139 / Chapter 8.3. --- Discussion --- p.142 / Chapter Chapter 9. --- General Conclusions --- p.149 / References --- p.153

Polymer based membranes play a key role in several industrially important gas separation technologies, e.g., removing CO2 from natural gas, with enormous economic and environmental impact. In this thesis, we develop a novel hybrid membrane construct comprised entirely of inorganic nanoparticles grafted with polymer chains. For all graft architectures studied, the permeability of several small gases and condensable solvents are higher in GNP membranes than the neat polymer analogs. More interestingly, the matrix-free GNPs displayed a non-monotonic peak in gas permeability as a function of grafted chain molecular weight, M_n, at a fixed grafting density, σ. Furthermore, in contrast to neat polymer membranes, which suffer from degraded performance over time due to chain densification and “aging”, the performance of GNP membranes is preserved for months to years. We show that these enhancements are not limited to a single polymer, thus we suggest that this grafting mechanism may be an option to improve permeability in polymer membranes in general. We conjecture the grafted polymer chains must stretch to fill the interstitial voids in the NP “lattice”, as such voids would be free-energetically unfavorable due to the relatively high surface tension of the polymer melt. Since this stretching leads to an unfavorable chain conformational entropy, we expect a decrease in the polymer density, which we verify experimentally as well as through molecular dynamics simulations. When a penetrant molecule is placed in these regions of highest distortion, the chains can assume more favored, undistorted conformations. This in turn creates a driving force for further penetrant uptake. Therefore, we systematically study the structure and dynamics of matrix-free GNP materials at various chain grafting densities and a wide range of graft molecular weight. Small angle scattering experiments reveal that the core nanoparticle spacing systematically increases with increasing molecular weight but the overall morphology remains amorphous and isotropic. Whereas previous studies1 have found the brush height in matrix-free GNPs scales as the degree of polymerization 〖~N〗^0.5, we find that the brush height in our systems scales 〖~N〗^0.7, indicating the chains are indeed highly stretched. Moreover, studies of the structural evolution upon swelling with solvent show that the brush is fully wetted and the solvent distribution is homogeneous within the film. Additionally, we systematically probe the dynamics of matrix-free GNP systems over broad length and time scales using linear and non-linear mechanical rheology, and broadband dielectric spectroscopy. The linear viscoelastic response shows that while the polymeric signal (e.g. glassy and Rouse dynamics) is equivalent for a range of graft chain lengths, the terminal flow of these materials is slowed by several decades compared to the neat melts of corresponding molecular weight. The low frequency (long time) response shows that below a critical molecular weight, these systems transition from polymeric to that of a colloidal system. To understand this behavior, a scaling theory is developed to describe the polymer brush conformation, which reveals that at this transition point the grafted particles behave as a system of packed “rigid” spheres. We note that the transition point coincides with the maximum observed in the transport behavior, and that the reduced system mobility may be responsible for the reduced aging effects. On the other hand, secondary relaxations for GNPs at this transition molecular weight are found to be faster than the neat polymer of corresponding molecular weight, which is attributed to a lower effective polymer density found in these samples. Therefore, the critical question underpinning this work is: how do the structure and dynamics influence and/or result from increased free volume in matrix-free grafted nanoparticle materials? We conclude that matrix-free grafted nanoparticle constructs allow for precise control of structure-property relationships over multiple length scales, and serve as a novel materials design platform with the potential to function as high performance gas separation technologies.

Abdominal aortic aneurysms are a focal dilation of the aorta which can be potentially life threatening if left untreated. Endovascular aneurysm repair (EVAR) is a noninvasive treatment that can reduce the mortality rate when compared to the standard open repair. Yet, EVAR is associated with other complications that can arise such as migration, endoleaks, or device related failures. These complications drive the need for reinterventions which have been shown to occur more frequently with EVAR than with open repair. The long term fixation and sealing characteristics of these devices is likely related to the nature of its apposition to the aortic wall. Currently there is little understanding of these mechanics and factors in how the device performs at the time of deployment. A computational model that reflects the compressive nature of an endovascular graft is beneficial in investigating these mechanics. The aims of the study are; 1) formulate an experimental methodology that captures the radial compressive nature of the stent graft, 2) develop a parameterized finite element model of the stent structure, and 3) compare the compressive behavior this model against the acquired experimental data. A 2 mil polyethylene sleeve was used to transfer a compressive vacuum pressure from the sleeve onto 10 independent stent grafts. The loading-unloading pressure was cycled from 0 to -50 mmHg (complete collapse) over 5 minutes. A pressure transducer and optical micrometer were used to capture the vacuum pressure and diameter relationship. All ten grafts compressed in a similar elliptical shape configuration. Commercial software was leveraged to construct a parameterized model of the stent geometry. All crest and trough vertex locations of the sinusoidal stent structure were validated within 1 mm of a measured value. A dynamic quasi-static computational simulation was completed that included large deformations and contact between the sleeve and stent as well as self-contact in the sleeve. Our results show that the model is representative of the experiments and can be used to interrogate how a stent graft will perform during certain stages of deployment and immediately after deployment with some caution in regard to the stated limitations.

<p> </p><p>The aim of the study was auditing medical records examine postoperative blood glucose levels after undergoing CABG surgery. Furthermore the aim was to determine if the ward staff abides the local guidelines frame of reference concerning each ward, regarding blood glucose measurements and blood glucose levels. The study included 70 patients undergoing CABG surgery at the cardiothoracic surgery, Uppsala University Hospital. The study was conducted by retrospective medical record auditing. Studied factors were postoperative blood glucose levels, number of registered blood glucose measurements, a current diagnosis of DM and preoperative HbA_1c. Mean level of blood glucose levels stayed continuously above the local guidelines frame of reference for both TIVA/TIMA and the care ward throughout the continuity of patient care. The number of registered blood glucose measurements per postoperative day at TIVA/TIMA where within the local guidelines. The result showed that the local guidelines frame of reference concerning the ward were not reached. A difference could be seen between patients with DM and patients without DM regarding the previously mentioned factors. Preoperative elevated levels of HbA_1c could have influenced the number of postoperative blood glucose measurements. Recommendations will therefore be too audit the current local guideline that concerns the treatment, therapy goals and the number of blood glucose measurements. Establishing criterions regarding termination of blood glucose measurements and the transfer day between TIVA/TIMA and the care ward are recommended.</p><p> </p>

CD4+CD25+Foxp3+ T regulatory (Treg) cells are critical in maintaining self tolerance and promoting the acceptance of allogeneic tissue/organ grafts. To be widely applied in clinical settings, there needs to be a readily available source of Treg cells, a requirement that is better met if non-histocompatible donor cells could be utilized in adoptive therapy. Therefore, to investigate the therapeutic potential of fully allogeneic Treg cells to control autoimmune disease or allograft rejection, we utilized IL-2R beta-deficient mice that exhibit rapid lethal autoimmunity due to low production of an ineffective population of Treg cells. We show that adoptive transfer of MHC-mismatched Treg cells into IL-2R beta-/- mice resulted in life-long engraftment of the donor cells, which exhibited skewed reactivity toward host alloantigens, and prevented autoimmunity. When such animals received skin grafts, they exhibited tolerance to those grafts that expressed MHC molecules from which the donor Treg cells were derived. Collectively, these data provide proof-of-principle that effective engraftment by allogeneic Treg cells controls autoimmunity and leads to favorable conditions for long-term acceptance of allografts. Current data indicates that CD4+CD25+Foxp3+ Treg cells exhibit a broad TCR repertoire. However, the relationship between this diversity and capacity to control a similarly diverse population of potentially autoreactive T cells remains to be defined. To investigate this issue, we assessed the TCR repertoire of chimeric donor Treg cells in IL-2R beta-/- mice that were adoptively treated with a diverse polyclonal Treg inoculums. We demonstrate that autoimmune disease was fully prevented by engrafted donor Treg cells in spite of a TCR repertoire that is less diverse than the input cells. However, in settings where the input TCR repertoire is limited by utilizing donor Treg cells that express a single TCR beta chain, control of disease was hampered, correlating with a limited TCR alpha repertoire within the engrafting donor Treg cells. Collectively, these findings suggest that for adoptive therapy, a diverse TCR repertoire of input Treg cell inoculums is an essential requirement for effective control of polyclonal autoreactive T cells but perturbations in the repertoire that results in significant limitation to this diversity may compromise Treg cell efficacy at fully keeping autoaggressive cells in check.

Thesis (M. Phil.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

The aim of the study was auditing medical records examine postoperative blood glucose levels after undergoing CABG surgery. Furthermore the aim was to determine if the ward staff abides the local guidelines frame of reference concerning each ward, regarding blood glucose measurements and blood glucose levels. The study included 70 patients undergoing CABG surgery at the cardiothoracic surgery, Uppsala University Hospital. The study was conducted by retrospective medical record auditing. Studied factors were postoperative blood glucose levels, number of registered blood glucose measurements, a current diagnosis of DM and preoperative HbA1c. Mean level of blood glucose levels stayed continuously above the local guidelines frame of reference for both TIVA/TIMA and the care ward throughout the continuity of patient care. The number of registered blood glucose measurements per postoperative day at TIVA/TIMA where within the local guidelines. The result showed that the local guidelines frame of reference concerning the ward were not reached. A difference could be seen between patients with DM and patients without DM regarding the previously mentioned factors. Preoperative elevated levels of HbA1c could have influenced the number of postoperative blood glucose measurements. Recommendations will therefore be too audit the current local guideline that concerns the treatment, therapy goals and the number of blood glucose measurements. Establishing criterions regarding termination of blood glucose measurements and the transfer day between TIVA/TIMA and the care ward are recommended.

Background: Myocardial failure and dysfunction is not uncommon during critical illness and following cardiac surgery. For optimal treatment, a better understanding of the effects of inotropic drugs is needed. In this thesis, two non-adrenergic mediated inotropes, milrinone and levosimendan were studied in different models of myocardial dysfunction. The study aims were to assess the following: the effects of milrinone on blood flow in coronary artery bypass grafts during CABG surgery; the effects of milrinone on left ventricular diastolic function during post-ischaemic myocardial dysfunction; whether milrinone or levosimendan are protective or injurious during acute myocardial ischaemia, and if levosimendan potentiates myocardial function when added to milrinone in an experimental model of post-ischaemic (stunned) myocardium. Material and Methods: In Study I, 44 patients undergoing coronary artery bypass surgery(CABG) were included as subjects. Milrinone or saline was administrated in a single dose during cardio-pulmonary bypass (CPB) and coronary graft flow measurements were recorded after 10 and 30 min following CPB. In Study II; 24 patients undergoing CABG had estimations of peak ventricular filling rates made before and after CPB with administration of milrinone or saline as a single dose during CPB, performed by assessment of the rate of change in diastolic cross-sectional left ventricular area. In Study III, energy-metabolic effects of milrinone and levosimendan were measured in an anaesthetized porcine model during 45 minutes of regional myocardial ischemia. Microdialysis sampling of metabolites of local ischemic metabolism allowed assessment of glycolytic activity and the degree of myocardial calcium overload. In Study IV, in a porcine model of postischaemic myocardial stunning, ventricular pressure-volume relationships were analyzed when milrinone or a combination of milrinone and levosimendan were given together. Results: In Study I, there was a clear increase in non-sequential saphenous vein graft blood flow with milrinone at 10 minutes (64.5 ± 37.4 compared to placebo 43.6 ± 25.7 ml/min (mean ± SD).). A decreasing but still measureable flow increase was seen for milrinone at 30 minutes. In Study II, an increase in early left ventricular filling rate (ventricular cross-sectional area rate of change,dA/dt) was seen in the milrinone treated group. Pre-bypass milrinone group dA/dt 22.0 ± 9.5 changed to post-bypass values dA/dt 27.8 ± 11.5 cm2/sec). Placebo group pre-bypass dA/dt was 21.0 ± 8.7 and post-bypass 17.1 ± 7.1 cm2/sec. A milrinone effect was demonstrated in an adjusted regression model (p = 0.001). In Study III, neither milrinone nor levosimendan led to a change in energy-metabolic activity during ischemia as reflected by interstitial glucose, pyruvate, lactate orglycerol. Neither drug exacerbated the relative myocardial calcium overload during ischemia. In Study IV, milrinone improved active relaxation (tau) in post-ischemic stunned myocardium, but did not markedly improve systolic function by preload recruitable stroke work. Levosimendan added to milrinone showed minimal effect on active relaxation but a positive effect on systolic function in combination with milrinone. Conclusions: We conclude that milrinone treatment leads to an increase in blood flow in newly implanted coronary saphenous vein grafts, and improves ventricular relaxation post-cardiopulmonary bypass. Neither milrinone nor levosimendan, in this porcine model, negatively influence myocardial energy metabolism or calcium overload during acute ischaemia. Addition of levosimendan to milrinone treatment during post-ischaemic ventricular dysfunction may provide additive inotropic effects on systolic function but probably not for active relaxation.

Living anionic polymerization techniques were applied to the synthesis of arborescent (dendritic) well-defined graft polymers having core-shell morphologies, with a hydrophobic core and a hydrophilic shell. Cycles of polystyrene substrate acetylation and anionic grafting yielded successive generations of arborescent polystyrenes. The anionic polymerization of styrene with sec-butyllithium provided polystyryllithium serving as side chains. These were coupled with a linear acetylated polystyrene substrate to obtain a generation zero (G0) arborescent polymer. An analogous G0 hydroxyl-functionalized polystyrene substrate with hydroxyl end groups was also obtained by a variation of the same technique, using a bifunctional organolithium initiator containing a hydroxyl functionality protected by a silyl ether group to generate the polystyrene side chains. These were coupled with the linear acetylated polystyrene substrate and subjected to a deprotection reaction to give the G0 polymer functionalized with hydroxyl groups at the chain ends. A similar procedure was used to generate a hydroxyl-functionalized arborescent G1 polymer from the corresponding G0 acetylated polystyrene substrate. The growth of polyglycidol chain segments was attempted from the hydroxyl-functionalized cores, to form a hydrophilic shell around the hydrophobic cores, but led to extensive degradation. A click reaction was also developed to synthesize the amphiphilic copolymers and was much more successful. In this case alkyne-functionalized arborescent polystyrene substrates, obtained by a modification of the hydroxyl-functionalized arborescent polystyrenes, were coupled with azide-functionalized polyglycidol side chains.

No description available.