VictorJuiz/thesis huggingface dataset:
Gene Therapy for Endothelial Progenitor Cell Dysfunction

Endothelial progenitor cells (EPCs) have reduced neovascularization capacity in the context of coronary artery disease (CAD) or cardiac risk factors (RFs). Since, endothelial NO synthase (eNOS) is critical to normal EPC function, we hypothesized that bone marrow cells (BMCs) from rats with RFs and EPCs from humans with CAD and/or RFs show dramatically reduced neovascularization capacity in vitro and in vivo, which can be reversed by eNOS overexpression. BMCs were isolated from rat models of type II diabetes and the metabolic syndrome, and we showed a significant reduction in their ability to stimulate neovascularization in vitro and in vivo. In humans, we isolated circulating ‘early EPCs’ from healthy subjects and patients with CAD and RFs, and transduced them using lentiviral vectors containing either eNOS or GFP (sham). EPCs from patients had reduced in vitro migration in response to SDF-1 or VEGF, which was reversed by eNOS-transduction. In co-culture with human umbilical vein endothelial cells (HUVECs) on Matrigel, eNOS-transduced EPCs contributed to increased and more complex angiogenic tube formation compared to sham-transduced cells. Human EPCs from patients were ineffective in enhancing ischemic hind limb neovascularization and perfusion in a nude mouse, whereas eNOS-transduced EPCs resulted in a significant improvement compared to sham-transduced cells. In a swine model of acute myocardial infarction (MI), eNOS- and non-transfected BMCs both increased left ventricular function compared to sham. However, there was no benefit to eNOS overexpression in this model. Various differences in the models and procedures may explain the incongruous results obtained. Taken together, these results show that eNOS overexpression significantly improves the neovascularization capacity of EPCs of human subjects with CAD and RFs and could represent an effective adjunctive approach for the improvement of autologous cell therapies for cardiovascular disease.

Keywords: cardiovascular disease
cell therapy
nitric oxide
Advisor: Stewart, Duncan John
Rheology of Foaming Polymers and its Influence on Microcellular Processing

The rheological properties of polymer melts and polymer/blowing agent (BA) solutions are determined experimentally and the influences of material rheological properties and crystallization on low-density foaming behaviour of polylactic acid (PLA) are investigated. Understanding the rheological properties of foaming polymers allows the optimization of polymer chemical structure and the development of technologies that produce desired cell morphologies. Although the technology for producing CO2-blown polystyrene (PS) foams is well established, the rheological properties of a PS/CO2 solution, especially its extensional property, are not well understood. In this study, these properties are determined with an in-house developed, online technique, and the measured data are compared with those from commercial rheometers. The online measurement system consists of a tandem foam extrusion system and a die for measuring pressure drops. Shear viscosity is determined from the pressure drop over a straight rectangular channel, while planar extensional viscosity from the pressure drop over a thin hyperbolic channel, taking into account the pressure drop due to shearing. Measured viscosities of the polystyrene without CO2 compare well with those from commercial rheometers. With the presence of dissolved CO2, both the shear and extensional viscosities of the polystyrene are significantly reduced. The influence of CO2 on the two viscosities is found to be similar to an increase of temperature. Polylactic acid is the first mass-produced biodegradable polymer, and has potential to replace petroleum-based polymers in foaming applications. In this study, the influences of material rheological properties and crystallization on the low-density, microcellular extrusion foaming behaviour of polylactic acids (PLAs) are investigated. Comparisons are made between linear and branched PLAs and between amorphous and crystalline PLAs. The branched PLAs are found to produce foams with higher expansion ratios and reduced open-cell content compared to the linear PLA. The foaming behaviour of the linear PLA, then, is significantly improved by adding a small amount of long-chain-branched PLA. The improved cell structure with branched PLAs is attributed to their relatively high melt strength and strain to break. For the first time, it is shown that crystallization, induced by cooling and macroscopic flow during processing, increases melt strength, which aids the production of low-density foams.

Keywords: polymer
rheology
foam
biodegradable
Advisor: Park, Chul B.
James, David F.
Molecular Investigation of Chloroethene Reductive Dehalogenation by the Mixed Microbial Community KB1

Bioaugmentation with Dehalococcoides-containing cultures is a successful technology for the remediation of chlorinated ethene-contaminated roundwater. The overall goal of this research was to identify and characterize genes that are used by a Dehalococcoides-containing culture, KB-1, during degradation of Trichloroethene (TCE) to ethene, via cis-Dichloroethene (cDCE) and vinyl chloride. Firstly, the diversity and dynamics of the microbial populations within KB1 was assessed using 16S rRNA clone libraries and quantitative PCR analyses. Secondly, reductive-dehalogenase-homologous- (RDH) genes in KB1 were identified, sequenced and their transcription compared through RNA-generated RDH cDNA clone libraries. Finally, to elucidate functionally important genes within the community, Shotgun metagenome microarrays were constructed and used to investigate transcription during dechlorination. Results of the phylogenetic analyses indicated that KB1 is a diverse community of microorganisms whose stability is enhanced by functional redundancy within the culture. To fully understand this diverse community of uncultivated microorganisms a metatranscriptome approach was used. Experiments with shotgun metagenome microarrays identified spots which were statistically significantly differentially expressed during dechlorination. These spots were then sequenced, revealing Dehalococcoides and non-Dehalococcoides-genes which are important during dechlorination. These results demonstrated that shotgun microarrays can be constructed without prior sequence knowledge and used to effectively examine differential transcription within an uncultivated community. Subsequently, all of the spots of the array were sequenced, and additional array experiments were conducted. Sequencing identified 24 reductive dehalogenase genes in the culture, and analysis of the microarray results indicated that many of these RDH genes were differentially expressed in response to certain chlorinated compounds. Interspecies interactions were also highlighted as results suggested that non- Dehalococcoides microorganisms provide partial corrinoids which Dehalococcoides salvages to synthesize cobalamin which is essential for reductive dehalogenation. Transcription of CRISPR-associated genes also indicated interaction between phage and other microorganism in the KB1 community. Overall these results provided sequence and transcription information about possible biomarkers for reductive dechlorination by KB1 and can be used for more effective design and monitoring of bioremediation technologies.

Keywords: Biodegradation
Microarrays
Advisor: Edwards, Elizabeth A.
Children's Perception of Speaker Identity from Spectrally Degraded Input

Speaker identification is a challenge for cochlear implant users because their prosthesis restricts access to the cues that underlie natural voice quality. The present thesis examined speaker recognition in the context of spectrally degraded sentences. The listeners of interest were child implant users who were prelingually deaf as well as hearing children and adults who listened to speech via vocoder simulations of implant processing. Study 1 focused on child implant users' identification of a highly salient speaker—the mother (identified as mother)—and unfamiliar speakers varying in age and gender (identified as man, woman, or girl). In a further experiment, children were required to differentiate their mother's voice from the voices of unfamiliar women. Young hearing children were tested on the same tasks and stimuli. Although child implant users performed more poorly than hearing children overall, they successfully differentiated their mother's voice from other voices. In fact, their performance surpassed expectations based on previous studies of child and adult implant users. Even when natural variations in speaking style were reduced, child implant users successfully identified the speakers. The findings imply that person-specific differences in articulatory style contributed to implanted children's successful performance. Study 2 used vocoder simulations of cochlear implant processing to vary the spectral content of sentences produced by the man, woman, and girl from Study 1. The ability of children (5-7 years and 10-12 years) and adults with normal hearing to identify the speakers was affected by the level of spectral degradation and by the gender of the speaker. Female voices were more difficult to identify than was the man's voice, especially for the younger children. In some respects, hearing individuals' identification of degraded voices was poorer than that of child implant users in Study 1. In a further experiment, hearing children and adults were required to provide verbatim repetitions of spectrally degraded sentences. Their performance on this task greatly exceeded their performance on speaker identification at comparable levels of spectral degradation. The present findings underline the importance of ecologically valid materials and methods when assessing speaker identification, especially in children. Moreover, they raise questions about the efficacy of vocoder models for the study of speaker identification in cochlear implant users.

Keywords: speaker identification
cochlear implants
children
speech perception
cochlear implant simulation
Advisor: Trehub, Sandra E.
Schellenberg, E. Glenn
Quantitative Ultrasound Characterization of Responses to Radiotherapy in vitro and in vivo

In clinical oncology and experimental therapeutics, changes in tumour growth rate or volume have been traditionally the first indication of treatment response. These changes typically occur late in the course of therapy. Currently, no routinely available imaging modality is capable of assessing tumour response to cancer treatment within hours or days after delivery of radiation treatment. Therefore, the goal of this thesis is to develop the use of ultrasound imaging and ultrasound characterization methods with frequencies of 10 to 30 MHz to assess non-invasively tumour response to radiotherapy, early, within hours to days after delivery of radiotherapy. Responses to radiotherapy were characterized initially in vitro in a well-controlled environment using cell samples. It was demonstrated experimentally that the changes in ultrasound integrated backscatter and spectral slopes were the direct consequences of cell and nuclear morphological changes associated with cell death. The research in vitro provided a basis for the in vivo research that characterized responses to radiotherapy in cancer mouse models. The results from mouse tumour models indicated that quantitative ultrasound could detect the regions in a tumour that corresponded in histology to areas of cell death. In order to understand the cellular morphological changes responsible for ultrasound scattering at these frequencies and assist in the interpretation of experimental data, numerical simulations of ultrasound scattering from four different cell lines exposed to radiotherapy were conducted and compared to experimental results. It was concluded that the increases measured in ultrasound backscatter could in part be explained by the increase in the randomization of cell nuclei resulting from the increase in the variance of cell sizes following cell death. In this thesis, it is demonstrated that ultrasound imaging and quantitative ultrasound methods were able to detect non-invasively early responses to radiotherapy in vitro and in vivo. The mechanism behind this detection was linked to changes in the acoustic properties of nuclei and changes in the spatial organization of cells and nuclei following cell death. This provides the groundwork for future investigations regarding the use of ultrasound in cancer patients to individualize treatments non-invasively based on their responses to specific interventions.

Keywords: 0541
0786
Advisor: Kolios, Michael Christopher
Czarnota, Gregory J.
Clinical Practice Guidelines: Sustaining in Organizational Memory

Organizational theory can assist in better understanding how changes made in clinical practice can be sustained in healthcare organizations. Organizational learning and knowledge transfer theories were used to develop and test a theoretical model, “Sustaining in Memory” (SIM) model, to explore how organizations disperse or distribute newly transferred knowledge in knowledge reservoirs situated in the organization. Three hypotheses were generated from the theoretical model and tested with data from a cross sectional postal survey of 148 patient/resident care units in one large Canadian province where a CPG on prevention of falls was widely disseminated. Findings confirmed that fall prevention practice knowledge was transferred and embedded in all six knowledge reservoirs; however, there were three specific knowledge reservoirs that were found to be significant predictors of perceived CPG adherence (activities consistent with the CPG recommendations). These were staff, policy and role expectation knowledge reservoirs. There was variation in the adherence to the eight CPG recommendations with greater adherence to recommendations that were mandatory. Additionally, findings showed that the relationship between staff knowledge reservoir and CPG adherence was the only relationship moderated by the practices that helped to prevent/address knowledge loss through various activities designed for reviewing and updating practice knowledge. Interestingly, although CPG adherence was reported significantly greater in LTC resident care units, its association with patient outcomes was much weaker than in hospital patient care units. Hospital units had significantly greater correlation between perceived CPG adherence and all four of the falls prevention outcomes reported by study participants. Lastly, quality management culture as managed by senior leaders in the organization was also found to be a significant predicator of adherence to the CPG. The research study validated key assumptions made in the theoretical model while helping to clarify the distinct influence of different knowledge reservoirs. The SIM model provided an alternate perspective within which to study knowledge transfer and sustainability of clinical practices and has potential to apply to other change initiatives. This study answered the call for greater theoretically driven studies of CPG implementation as well as attention on the organizational influences of CPG implementation and sustainability.

Keywords: Organizational Memory
Clinical Practice Guidelines
Sustainability
Evidence Based Practice
Advisor: Lemieux-Charles, Louise
Davis, David
De la utopía de la solidaridad al dolor del cambio: discursos alrededor de un terremoto

This dissertation proposes an analysis of representative texts that portray the earthquake that hit Mexico City in 1985 as a historical event that contributed to forging new ways of interaction among the people itself, as well as between the community as a whole and its government. By examining the representations of this historically important episode in the life of the city, this project compensates for a significant omission of literary criticism—that has relegated the substantial corpus of texts about this catastrophe to brief comments or footnotes on other topics. Through analysis of testimonial chronicles, newspaper articles, political cartoons, music videos, poetry, drama, and narratives, this dissertation investigates the process through which intellectuals created discursive constructions of a new relationship between Mexican society and its government. The following pages give an account of the debate to shape the historical interpretation of the catastrophe: some texts challenged the patrimonialism institutionalized by the government bureaucracy of the PRI State, while others supported the structures in place even though they acknowledged the need for a nimbler bureaucracy. Therefore, this study is focused on texts that incorporate previous discursive traditions to propose new symbolic ways to understand the nation after the earthquake. This discussion engages texts by authors committed to diverse perspectives—such as Elena Poniatowska, Carlos Monsiváis, José Emilio Pacheco, Carlos Olmos, Enrique Serna, and Rodrigo Fresán, among others—to offer a panorama on the arguments presented on the cultural field. This dissertation considers four specific moments in the construction of the new national narrative: (1) the call for solidarity with the victims of the disaster; (2) the redefinition of the idea of civil society; (3) the debate within mass media to impose a particular meaning to both solidarity and civil society; and (4) the questioning of the main discourses related to the earthquake. This study illuminates the ways that the earthquake narratives have been deployed to challenge political inequities and injustices and to attempt political change towards a modern Mexican State.

Keywords: Mexico City 1985 Earthquake
Mexican Literature XXth Century
Poniatowska, Elena
Monsivais, Carlos
Solidarity
Civil Society
Disaster
Fresan, Rodrigo
Olmos, Carlos
Testimonial narratives
Advisor: Rodríguez, Néstor E.
Transition Metal-catalyzed Carbon-carbon/Carbon-heteroatom Bond Formation Reactions Utilizing Strained Ring Systems

This thesis focuses on the development of carbon-carbon/carbon-heteroatom bond forming reactions using strained ring systems under transition metal catalysis. The first chapter describes the use of bifunctional organoboron reagents with a rhodium catalyst to synthesize carbocycles through a cascade sequence. The reaction of norbornene derivatives gives vinylcyclopropane and cyclopentene products in moderate to good yield. The mechanistic proposal and insights into the reaction mechanism are presented. Preliminary results from studies toward an enantioselective sequential addition/cyclization process are described. The methodology is subsequently applied in the synthesis of a variety of polycyclic heteroaromatics using bifunctional heteroaryl boronate esters. The second chapter describes studies toward the formation of carbon-heteroatom bonds using cyclopropane derivatives. Under a recently developed Pd(OAc)2/PhI(OAc)2 catalytic system, methylenecyclopropanes are isomerized to substituted pyridines via a sequential fragmentation/cyclization process. Under same reaction conditions, allylic acetate products are obtained from the isomerization of cyclopropanes through a similar process.

Keywords: rhodium
vinylcyclopropane
palladium
catalysis
Advisor: Lautens, Mark
The Regulation of Expression of Hemokinin-1

The regulation of the immune system is complex, with many factors involved in controlling immune cell development, activation and homeostasis. These factors include neuropeptides as well as classic immunoregulatory molecules such as cytokines, chemokines and hormones. Neuropeptides and tachykinins in particular are known to be involved in immune response modulation through a cascade of events including vasodilation, plasma extravasation, the activation of immune cells, the secretion of pro-inflammatory cytokines and the recruitment of more immune cells. Furthermore, there is growing evidence that tachykinins play a role in hematopoiesis with Substance P as the proposed effector molecule. In 2000, our lab discovered a new tachykinin with remarkable structural similarity to SP and SP-like neurokinin receptor binding affinity. This molecule was designated Hemokinin-1 due to its expression in hematopoietic cells and its function in B cell development. Further gene expression analysis of HK-1 reveals a wide expression pattern although HK-1 transcripts are found predominantly in peripheral tissues while SP is mainly expressed in neuronal tissue. Based on this differential expression pattern, it has been suggested that HK-1 may act as the peripheral tachykinin and may have functions distinct from SP. In addition, given the crossreactivity of the SP antibodies to HK-1, it is important to determine whether HK-1 is the actual mediator of some functions previously attributed to SP. In this thesis, we examine the differential expression pattern of HK-1 to determine molecular mechanisms of regulation of HK-1 transcription and ultimately provide clues to its function in the immune system. In our analysis of the HK-1 promoter, we found a major difference in the basic transcriptional control of HK-1 and SP at the level of transcription initiation and identified several transcription factors including CREB and NFκB involved in regulating TAC4 gene expression in immune cells. Data presented in this thesis also reveal that the HK-1 gene is a direct target of Early B-cell Factor, a transcription factor known to activate B cell-specific genes as well as genes involved in adipogenesis and neuronal development. Our results show EBF regulates HK-1 gene expression in differentiating B cells as well as a monocytic cell line. Our data indicate EBF may also be responsible for the high levels of HK-1 transcript in the olfactory epithelium, suggesting a bridge between the nervous system and the immune system.

Keywords: Tachykinin
Neuropeptide
Neuroimmunology
Transcription
Promoter
Expression
Advisor: Paige, Christopher J.
Wu, Gillian E.