VictorJuiz/thesis huggingface dataset:
Retinal Stem Cells: Expansion and Progeny Characterization
Keywords: Bioreactors
Microcarriers
Retinal degeneration
Retinal stem cells
Stem cells
Vision

Growing retinal stem cell (RSC) clonal spheres in traditional static culture is associated with low expansion rate and poor survival attributed to loss of cells during the enzymatic dissociation steps. Another problematic issue is the difficulty to mimic in vivo stem cell niche conditions. Using our traditional lab protocol, only 0.2% of the pigmented ciliary epithelium cells (CE) give rise to floating RSC clonal spheres in serum free conditions. These issues have hindered our ability to study the signaling pathways governing RSC proliferation and expansion in vitro. To overcome these limitations, I used microcarriers (MCs) in a suspension stirring bioreactor (SSB) to help achieve sufficient numbers suitable for differentiation and transplantation. Using this new protocol, I achieved a significant (10-fold) enrichment of RSC yield compared to conventional static culture techniques using a combination of FACTIII MCs and relative hypoxia (5%) inside the bioreactor. My work showed that hypoxia (5% O2) was associated with better RSC expansion across all platforms which was attributed to hypoxia-induced boosting survival and/or symmetric division of stem cells. RSC spheres were thought to be unvaried and were randomly picked and placed on laminin extracellular matrix (ECM) in static plates. In my work, I found noticeable variance in the pigment distribution between RSC spheres which led me to categorize them into three different groups according to their pigmentation, I also noted that this variance in pigment level and distribution was associated with contrasting differentiation potentials. RSCs were classified into three morphological groups: heavily pigmented (HP), lightly pigmented (LP) and centrally pigmented (CP) spheres. Unlike the other two sphere types, CP spheres were capable of producing highly proliferative progenitors (producing large number of cobblestone-like cell lawns) in adherent culture that differentiate into retinal pigment epithelium (RPE) cells. I found that the individual stem cells that (clonally) formed the three sphere types appear homogeneous, but it is their downstream progenitors that are different. I showed that CP spheres contain a population of early RPE progenitors that respond to proliferative signals from the surrounding non-pigmented neural retinal cells while The HP and LP spheres do not respond to these signals.
Association Between Early Life Exposure to Phthalates and Organophosphate Esters and the Development of Childhood Asthma and Wheeze
Keywords: Asthma
Children
House dust
Organophosphate esters
Phthalates
Wheeze

Asthma is the most common chronic disease among children. Children spend most of their early life indoors, exposed to chemicals used in consumer and building products, which may present a risk to asthma development, including phthalates, used as plasticizers, and organophosphate esters (OPEs), used as flame retardants and plasticizers. Few epidemiological studies have examined early life exposure to these chemicals and the development of childhood asthma, as well as the interplay with genetics, which was examined by this dissertation using data from the Canadian CHILD Cohort Study. Using urine samples from 1,578 children collected across early life and 726 house dust samples collected at 3-4 months, I found that Canadian children have ubiquitous early life exposure to phthalates and OPEs. I found higher phthalate metabolite concentrations among children in lower income families. OPE concentrations were higher in dust collected here compared to other studies, possibly due to sampling of the child’s sleeping environment that contains sources of OPEs and phthalates. Using a case-cohort study, I examined the association between early life exposure to phthalates and OPEs, measured in house dust samples collected at 3-4 months, and the development of asthma at 5 years and recurrent wheeze between 2 to 5 years. I found a four-fold increased risk of asthma associated with the highest concentration quartile of di(2-ethyl-hexyl) phthalate (DEHP) and a two-fold increased risk of recurrent wheeze across all quartiles of DEHP compared to the lowest quartile. For OPEs, I observed a two to four-fold increased risk of asthma diagnosis across quartiles of tris(2-butoxyethyl) phosphate exposure compared to the lowest quartile. Using a Genetic Risk Score (GRS) combining multiple genetic loci, I examined whether genetics modifies the association between early life phthalate exposure and the risk of childhood asthma and recurrent wheeze. The GRS did not modify the association with childhood asthma or recurrent wheeze. These results highlight the need to reduce exposure to phthalates and OPEs during early life, especially the first year of life, and the importance of exposures among low-income populations and within the sleeping microenvironment.
The Sustainment and Sustainability of Quality Improvement Initiatives for the Health Care of Older Adults
Keywords: Implementation science
Older adult
Quality improvement
Sustainability

Quality Improvement (QI) is increasingly viewed as the vehicle of choice by health care organizations seeking to respond to the changing health care needs of an aging population while making efficient use of limited resources. However, evidence suggests that 40% to 60% of QI initiatives fail to achieve lasting improvements. Despite the potential waste this statistic represents, we have a limited understanding of factors which promote a QI intervention’s continued use in practice (sustainment) and the maintenance of its benefits (sustainability). Moreover, existing research has largely focused on large academic institutions in urban centres. As such, recommendations derived from these studies may not be appropriate for less-resourced, rural, or remote settings, where adaptations—planned changes to the intervention—may be needed to ensure its survival. The impact of such adaptations on QI sustainment or sustainability has not been studied. This thesis draws from a scoping review and subsequent artificial neural network analysis of empirical studies of the sustainment and sustainability of QI interventions for the health care of older adults to identify contextual, intervention and implementation factors which predict sustainment and sustainability. This model significantly predicted sustainability, but not sustainment. Omission of organization type, intervention target, or reported adaptations resulted in a significant loss of predictive power. To further investigate this result, I conducted a comparative case study to examine how the dynamic interaction between adaptations and organizational context impacts sustainment and sustainability. By comparing 3-year trajectories for elder care QI interventions implemented through participation in a quality improvement collaborative in a 375-bed academic hospital and a 56-bed remote hospital 2500 km away from its nearest referral centre, I found evidence that ongoing adaptations which are responsive to changes in organizational or environmental context (e.g. patient needs, government and local health authority supports) promote sustainment. In addition, adaptations that promote sustainment and are consistent with the core functions of a QI intervention contribute to the sustainability of QI. To close, I offer a new framework informed by organizational learning theory which will help contextualize adaptations’ impact on the people, tasks and/or tools of an intervention and its long-term sustainment and sustainability.
Identifying Novel Therapies to Reduce Injury following Ischemia Reperfusion in Kidney
Keywords: Acute Kidney Injury
BRD4
Ischemia Reperfusion Injury
NEVKP
NF kappaB

Renal ischemia reperfusion injury (IRI) is associated with early inflammation, including neutrophil infiltration, that exacerbates the initial ischemic insult. The molecular pathways involved in these responses are poorly characterized and there is no treatment targeting these early events. We first performed a proteomic analysis of porcine kidneys biopsies collected during transplantation to identify early changes in protein expression following IRI. Systems biology analysis identified animportant role of inflammation, specifically pathways converging on NFκB. Normothermic exvivo kidney perfusion of kidneys during transplantation attenuated inflammation. Based on these findings, we then performed an in silico analysis and confirmed marked changes in NFκB-mediated gene expression in early renal IRI. We then evaluated the effect of NFκB-blockade with a BRD4 inhibitor on neutrophil adhesion to endothelial cells in vitro prior to testing the effect of BRD4 inhibition in an in vivo murine IRI model. BRD4 inhibition attenuated TNFα-induced and hypoxia re-oxygenation-induced neutrophil capture and adhesion to endothelial cells in vitro, and improved cell viability following hypoxia re-oxygenation. In vivo, IRI led to increased expression of pro-inflammatory cytokines and adhesion molecules at 6 hours post-IRI with sustained upregulated expression up to 48 hours post-IRI. These effects were attenuated, in part, by pretreatment with the BRD4 inhibitor. Flow cytometry analysis showed absolute neutrophil counts increased significantly in the bone marrow, blood, and kidney 24 hours post-IRI. Activated neutrophils also increased in the blood and kidney as early as 6 hours post-IRI and remained elevated at 24 and 48 hours-post IR. BRD4 inhibition reduced both total and activated neutrophil counts in the kidney. IR-induced tubular injury correlated with the neutrophil infiltration and was reduced by BRD4 inhibition. In summary, NFκB signaling is the primary pathway upregulated following SCS, and targeting NFκB with a BRD4 inhibitor reduces neutrophil infiltration, neutrophil activation, and tubular cell injury in kidneys subjected to IRI. BRD4 inhibition may represent a new therapeutic approach to the management of acute kidney injury.
Influencing Oral-nasal Balance in Speech and Song
Keywords: hypernasality
oral-nasal balance
resonance
singing voice pedagogy
speech language pathology
velopharyngeal sphincter

Oral-nasal balance is dependent on the valving of the velopharyngeal sphincter. This dissertation examined the control and modification of oral-nasal balance in speech and song. Literature was reviewed from the fields of speech science and singing voice pedagogy, which motivated three projects. The first project (Santoni et al., 2018) explored the role of altered nasal signal level feedback on the regulation of oral-nasal balance in singing in trained and untrained singers. Results indicated that all participants showed lower nasalance scores in response to both increased and decreased nasal signal level feedback. The findings implied that trained singers’ internal models for controlling oral-nasal balance may not be as refined as those that guide other vocal parameters. The second project (Santoni et al., 2019) explored the influence of voice focus adjustments (forward and backward vocal tract shape and length modifications) (Boone, 2007; Boone et al., 2010) on the control of oral-nasal balance in typical speakers in speech and song. Results indicated that forward focus led to higher and backward focus to lower nasalance scores. There was one exception wherein one female participant produced lower nasalance scores in forward focus during the nasal stimulus. The results confirmed that voice focus maneuvers influence oral-nasal balance in typical speakers. Findings from project 2 led to the clinical experiment described in project 3. The third project (Santoni, Thaut Bressmann, 2020) explored the influence of voice focus adjustments on the control of oral-nasal balance in speakers with hypernasality in speech and song. Results indicated that for a group of five speakers with hypernasality, forward focus resulted in higher and backward focus resulted in lower nasalance scores. There was one exception wherein one male participant produced lower nasalance scores in forward focus during the nasal stimulus. The results provided preliminary evidence that voice focus maneuvers influence oral-nasal balance in speakers with hypernasality. With further development of the voice focus method, the intervention could become a useful therapeutic approach for speakers with hypernasality.
The Precarity of Men: Youth, Masculinity, and Money in a Papua New Guinean Town
Keywords: Masculinity
Men
Money
Papua New Guinea
Youth

This dissertation is a study of uneducated young men (“youths”) in urban Papua New Guinea (PNG). Seeking to move beyond analyses that focus upon the themes of rupture and alienation caused by socio-economic changes that impinge upon young men’s abilities to mature and leave them “stuck” as youth, I deploy both historical and ethnographic data to examine how young men’s lives have been shaped by, and how they in turn shape their lives in the wake of change. Part I of this dissertation explores how the masculine life course and men’s aspirations were recast as local populations were incorporated into the nation state during the colonial era. In particular, I bring attention to the way in which becoming an educated person and living in town became key distinctions that structure post-colonial society. Part II of this dissertation draws upon 24 months of ethnographic research with men who experience the abjection of being forced out of school and turn to several activities: crime, rugby league football, and street sales. These activities provide men with parallel educational trajectories and the ability to claim a place in the city while aligning themselves with core masculine values. Although these activities appear to be a response to exclusion from formal wage labour opportunities, local views of money prevent such an interpretation. Money, I argue, is viewed as an inalienable object that men use as partible complements of their gendered substance, so stolen money or money from rugby (“easy money”), cannot be held, and is instead rapidly spent to re-enter circulation. Instead, men participate in crime and rugby to cultivate “fame,” that is conceived of as the socio-spatial extension of the self through the circulation of “name” and “face.” Although fame is so attractive to men that they may consciously try to prolong their status as youth as they continue to seek it out, this fame is fleeting, and depends upon forsaking social reproduction. “Street sales,” in contrast, allow men to generate a special kind of wealth (“hard work money”) that they can use for provisioning. Through “fathering,” which is predicated upon the flow of material resources to their children, men pass on their name and face to their children. Through partible personhood men thereby transcend death and achieve enduring fame. Attending to men’s practices illustrates how, while social change has made masculine social maturity increasingly disaggregated, men’s core values and desires remain coherent over time, including the desire to cultivate the body, achieve fame, and reproduce themselves socially within a framework of partible personhood. Similarly, examining young men’s actions illustrates how, while young men’s lives are shaped and constrained by broader social processes, being a youth can also be examined as a socially productive period as well.
Uncovering the Neural Pathways Mediating the Bladder-inhibitory Effects of Percutaneous Tibial Nerve Stimulation: A Novel Approach to Treating Overactive Bladder
Keywords: Bladder
Neuromodulation
Saphenous Nerve
Tibial Nerve

Each year, millions of Canadians suffer from the debilitating effects of overactive bladder (OAB) resulting in profound socio-economic costs. Various treatment algorithms, such as behavioral therapies and pharmacotherapies have been introduced to counter the unwanted results of this disorder. Such treatments are, however, modest in their effectiveness. An alternative to conventional therapies, neuromodulation, is proven efficient in reducing OAB symptoms. However, it’s the invasiveness and the surgical cost (e.g., sacral nerve stimulation – SNS), which precludes it as a first line of treatment in the algorithm of incontinence care. Consequently, percutaneous tibial nerve stimulation (PTNS) was introduced as a less-invasive yet effective therapy for treating OAB symptoms. In PTNS, clinical efficacy is achieved by repeatedly applying electrical stimulation through a percutaneous needle electrode, which is used to target the tibial nerve (TN). However, the lack of rationale for using the set stimulation parameters (20 Hz coupled with intensities below the motor threshold), the need for repeated treatments to maintain the therapeutic effects as well as the inconsistent response rates pose a major barrier to its widespread use. The focus of this work is therefore, to rationalize the lack of consistency in the bladder-inhibitory output following standard TNS techniques. In particular, we investigated the role of saphenous nerve (SAFN), largest cutaneous branch of the femoral nerve which, intercedes with the anatomical point of PTNS delivery, in modulating bladder function. This project uses well-established animal models to explore and systematically characterize the effects of TNS and SAFNS on bladder function and is divided into three main aims. The first aim focuses on rationalizing the inconsistency in response rates observed during non-selective TNS approaches by optimizing the role of stimulation parameters. The second aim targets the investigation of SAFN afferents in inhibiting bladder activity in a continuous urodynamic model. Finally, the last aim validates the consistency of SAFN-evoked bladder inhibitory reflexes at high stimulation amplitudes and its role in the development of a model for underactive bladder (UAB). Together, these results improve our understanding of the neural network underlying the therapeutic output of PTNS and the role of SAFN afferents within the urodynamic circuitry.
The Sensual Body and Artistic Prowess in Netherlandish Painting ca. 1540â 1570
Keywords: Antwerp
Erotics
Nude
Renaissance
Senses

In the middle of the sixteenth century, Netherlandish painters turned their attention toward the sensual nude. The leading contemporaries of Pieter Bruegel, including Frans Floris, Willem Key, Jan Massys, Maerten van Heemskerck, and Michiel Coxcie, favoured subjects that allowed them to elaborate their respective approaches to the ideal body. Artistsâ deliberate attention to the visual and tactile qualities of their painted figures had affective and artistic aims: painters sought to cultivate empathetic responses in their viewers while simultaneously asserting their individual brands. These artists also favoured subjects that presented the sensual nude as a problemâ an object for erotic delectation and one that could raise salient social concerns around gender, love, and coupling. An important feature of the paintings in this study is the way they orchestrate the possibility for contrasting points of view, thus complicating attempts to derive unequivocal interpretations. Indeed, contemporary rederijker drama, public festivity, vernacular literature and poetry, authoritative classical texts, and prints from across Europe suggest the range of issues that might have been projected onto Netherlandish depictions of the nude. While little is known of the patrons of such works, the scale, quality, and erudite subject matter point to a relatively affluent and educated class of individual; we know, for example, that Frans Florisâ s nudes were collected by Antoine Perrenot de Granvelle, a Habsburg official and the Bishop of Arras, and by the wealthy Antwerp financier, Nicholas Jonghelinck. Such patrons were as attracted by the visceral, affective qualities of the sensual body as they were by the opportunities it gave to display their erudition. They also valued how the leading artists adapted the fashionable formal vocabulary of antiquity and post-Raphaelesque figure painting to Netherlandish thematic demands and artistic traditions. By allowing their works to negotiate between the international and the local, Frans Floris and his contemporaries were active participants in a discourse on the sensual nude that had regional relevance and pan-European purchase. This very prominent and prestigious image category must be better integrated into art historical narratives of Netherlandish painting and Renaissance art.
Uncovering ‘Cryptic’ Natural Products from Streptomyces Bacteria
Keywords: Antibiotics
Cryptic Metabolites
Microbial Interactions
Natural Products
Secondary Metabolism
Streptomyces

The Streptomyces bacteria produce natural products that have potent biological activity against other organisms: 60% of our antibiotics are derived from this source. Genome sequencing reveals genes for many more. One view in the field is that these “cryptic” metabolites could serve as badly needed antibiotics for antibiotic resistant infections. However, many of them are produced at too low yields for structural and mechanistic characterization. The top priority is finding broadly applicable approaches to enhancing the yields of these molecules. To address this, I took advantage of a conserved regulator of specialized metabolism to develop a generally applicable tool, called AfsQ1*, that heterologously induces many specialized metabolic genes. Using this technology, I developed two antibiotic discovery screens. First, I identified afsQ1*-induced antibacterial activities and purified the active agents. This led to the discovery of the antibiotic siamycin-I, a potent inhibitor of antibiotic resistant Gram-Positive bacteria. I demonstrated that this compound targets the lipid-II component of cell wall biogenesis, the first of this class of molecules to do so. The second approach used comparative metabolomics to identify afsQ1*-induced novel masses. By NMR I identified a new pepticinnamin analogue, whose family are inhibitors of an eukaryotic post-translational modification called farnesylation. Farnesyl transferase inhibitors were previously investigated (unsuccessfully) as anticancer medicines. I demonstrate, however, that they are candidates for antifungal therapy, because they block morphological switching- a key virulence trait in lower fungi. This work suggests a new paradigm in antifungal therapy. Finally, I dissect an interaction between Lactobacillus reuteri and C. albicans. When co-cultured together C. albicans cannot undergo filamentous growth and I found that this inhibition is molecule-mediated. 1-acetyl β-carboline is the active metabolite isolated from L. reuteri and I found that its production is prevalent throughout the Lactobacillus genera. I also synthesized a new β-carboline analogue for future clinical trials.