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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
191

Epigenetic and genetic profiles of rare renal cancers

Slater, Amy Amelia January 2016 (has links)
The aim of this study was to characterise the genetic and epigenetic profiles of rare forms of sporadic renal cancers (RCC) and identify differential patterns of DNA methylation or somatic mutations that may permit distinction between different subtypes of RCC and could facilitate disease prognosis or identify molecular pathways that could be targeted therapeutically. Illumina Infinium HumanMethylation 450K BeadChip permitted the comparison of the epigenome of the malignant chromophobe RCC and the benign renal oncocytoma. This study identified several genes to be differentially hypermethylated in chromophobe RCC, and renal oncocytoma showing that although both visually and pathologically similar, both tumours have a distinct methylation pattern. Whole exome sequencing (WES) of renal oncocytoma samples identified somatic mutations in eighteen genes involved in a variety of cellular functions. Sanger sequencing was then used to confirm the mutations identified, followed by further screening by Sanger in a cohort of additional renal oncocytoma samples to identify if the somatic mutations are recurrent. Modern high throughput and quantitative techniques have permitted further characterisation of these rare renal cancers and have enabled unique insights into their molecular genetics, findings that may hopefully be of clinical benefit in the future.
192

Novel insights into the clinical heterogeneity and treatment of chronic lymphocytic leukaemia

Kwok, Marwan Cheng Kuang January 2018 (has links)
Chronic lymphocytic leukaemia (CLL) is characterised by marked disease heterogeneity and is currently incurable. This thesis presents work undertaken to discover novel biological and therapeutic insights through the investigation of spontaneous CLL regression, the evaluation of ATR inhibition as a therapeutic strategy, and the assessment of the impact of post-treatment minimal residual disease (MRD) in CLL. Firstly, spontaneous regressed CLL tumours were found to express somatically mutated IGHV genes, display unresponsiveness to IgM and IgD BCR stimulation and exhibit a phenotype of short telomeres with low CD49d expression, suggesting a model in which the CLL clone undergoes an initial period of proliferation which subsequently subside into a state of anergy and low proliferation. Secondly, ATR inhibition was found to be a promising therapeutic target for CLL tumours with TP53 or ATM defects. Treatment with ATR inhibitor induced synthetic lethality and selective cytotoxicity to these tumours in vitro and in vivo, and sensitised them to chemotherapy and ibrutinib. Finally, MRD negativity was found to predict for 10-year survival in CLL independent of the type and line of treatment, as well as known prognostic factors including adverse cytogenetics, supporting its use as a prognostic marker and potential therapeutic goal in CLL.
193

Epigenetic analysis of childhood leukaemia and the Hippo pathway

Dunwell, Thomas Lawson January 2010 (has links)
Hypermethylation of CpG islands is one of the many processes that a developing cancer cell may use for the inactivation of tumour suppressor genes. The Sav/Hippo/Warts pathway was originally identified in Drosophila and shown to be responsible for controlling both growth and apoptosis, implying this is a tumour suppressor pathway. This pathway is both evolutionarily and functionally conserved in mammals. Work presented here shows that apart from FAT1 and YAP other pathway members are not epigenetically silenced in common epithelial or haematological cancers. FAT1 and YAP were frequently methylated in childhood acute lymphoblastic leukaemia (ALL) but unmethylated in epithelial cancers. Childhood ALL is a blood cancer with peak prevalence between the ages of 3-5 years. The epigenetics of this cancer were examined with three separate approaches; the first, a candidate gene approach, second a NotI restriction enzyme based array examining the methylation of genes residing on chromosome 3, and thirdly the methylated-CpG island recovery assay (MIRA) combined with CpG island arrays examining methylation on a genome-wide scale. These approaches identified a large number of novel genes which were frequently methylated in ALL. Many of the identified genes were new methylation targets and were shown to be likely targets for methylation in both common epithelial and haematological cancers. A series of these genes was seen to be specifically methylated in different leukaemia sub types, and to cluster T-ALL and B-ALL samples into high and low methylation clusters. When examined in chronic lymphoblastic leukaemia (CLL) methylation of two of the above genes was associated with disease progression and methylation of another gene was associated with response to clinical treatment.
194

The use of alginates and polyphenols in medicinal iron chelation for the improvement of colonic health

Horniblow, Richard David January 2016 (has links)
Iron is central to the aetiology of gastrointestinal disease. Specifically, the toxic effects of excess, unabsorbed "luminal" iron ingested from the diet has been shown to be important in the development of inflammatory bowel disease and intestinal cancer. A platform for therapeutic intervention is likely to involve chelation of this luminal pool of iron. As such, a range of dietary iron chelators have been tested for their iron binding capacity. Natural biopolymers extracted from seaweed (alginates) and a variety of natural polyphenolic compounds were stratified in terms of their iron binding potential. One alginate, Manucol LD, was unique in its iron binding and demonstrated luminal iron chelation properties. With respect to the polyphenols, only one of the tested compounds (quercetin) displayed iron chelation activity in vitro and was able to suppress cellular concentrations of reactive oxygen species acting as an antioxidant. As such, it has been demonstrated that a unique alginate, Manucol LD, is an excellent candidate for sequestering luminal iron present in the gastrointestinal tract. These results underpin the rationale in utilising these types of natural and safe bio-polymers for the prevention and treatment of gastrointestinal disease.
195

PTTG, PBF and p53 in head and neck cancer

Modasia, Bhavika January 2017 (has links)
Head and neck squamous cell carcinoma (HNSCC) is the 6th most common cancer worldwide and poses a significant health burden due to its rising incidence. The proto-oncogene PTTG is overexpressed in HNSCC and correlates with poor patient prognosis. A recent unpublished GEO profile eDNA array analysis has further suggested a potential upregulation of its binding partner PBF in HNSCC. PTTG and PBF cause transformation in vitro and tumour formation in vivo, both effects thought to be partly mediated by their interactions with the tumour suppressor protein p53. Dysregulation of the p53 pathway is frequently observed in HNSCC, thus alluding to the importance of functionally active p53 in the suppression of HNSCC initiation and progression. The work presented in this thesis describes the functional relationship between PTTG, PBF and p53 in HNSCC. Initial studies confirmed that PTTG and PBF are overexpressed in HNSCC tumours compared to matched normal tissue. In addition, high tumoural PTTG expression correlated with HPV status, whereas high tumoural PBF expression was associated with a significant gender bias. Further investigations established that PTTG and PBF functionally interact with p53 and cooperate to reduce p53 protein stability in HNSCC cells. Moreover, attenuation of PTTG or PBF expression led to dysregulated expression of p53-related genes involved in DNA repair and apoptosis, indicating that both proto-oncogenes may serve to promote genomic instability and HNSCC cell survival. Functionally, depletion of PTTG or PBF significantly repressed cellular migration and invasion, and impaired colony formation in HNSCC cells. Overall, this research has provided novel insights into the roles of PTTG and PBF in HNSCC tumour initiation and progression, through modulation of p53 activity and function.
196

Nuclear magnetic resonance spectroscopy based metabolomics of breast cancer in hypoxia

Chong, Geokmei January 2015 (has links)
Hypoxia has emerged as a crucial part of the aetiology of tumours. It is a negative prognostic factor which is associated to chemoresistance, invasiveness and metastasis. There is a strong association between hypoxia and metabolic transformation in breast cancer due to the alterations of multiple metabolic pathways. However, the current understanding of the nature of metabolic alterations in hypoxia is insufficient. This thesis uses NMR as a tool to investigate both the static metabolome by measuring metabolite concentrations, as well as to determine \(^1\)\(^3\)C metabolic fluxes using stable isotope tracers to reveal metabolic pathway alterations by hypoxia in vitro and by tumour growth in vivo. Firstly, we developed the \(^1\)\(^3\)C isotopomer distribution (CID) analysis to quantify metabolic fluxes by following the evolution of specific isotopomers of specific pathways of interests. MCF7 breast cancer cells were analysed in hypoxia using an integrated approach using gene expression, steady-state metabolite levels and \(^1\)\(^3\)C metabolic flux analysis to pinpoint hypoxia induced metabolic alterations. These most significant alterations were an up-regulation of the pentose phosphate pathway and a down-regulation of mitochondrial oxidative metabolism by lowering the PDH flux. The latter was partially compensated by carbon entry into the mitochondria by increasing flux through pyruvate carboxylase (PC). Further attention was focused towards identifying the shifts in metabolic activity in PC altered cells using [1,2-\(^1\)\(^3\)C]glucose and [3-\(^1\)\(^3\)C]glutamine as precursor nutrients correlated to cellular transformation potential accessed by cell viability. Finally, the \(^1\)\(^3\)C labelled glucose strategy was applied to a cancer model in mice model by infusing mice with [1,2-\(^1\)\(^3\)C]glucose. \(^1\)\(^3\)C glucose administration protocol was optimised in order to enable an investigation of \(^1\)\(^3\)C metabolic fluxes in tumour tissue to identify metabolic pathway differences between earlier stage and advanced stage of mammary gland tumours. In conclusion, an NMR based metabolomics analysis is suitable for discovering metabolic pathway alterations using both in vitro and in vivo models.
197

Vocational teachers' experiences of using an online learning platform

Wong, Bo Man January 2018 (has links)
Much research has been carried out to demonstrate how the online platforms can be used to improve teaching and learning processes. However, they have been less explored in relation to vocational education, where the situation is often more complex and the possible solution options tend to be more constrained than in the contexts where these online technologies have been created. The aim of this research is to investigate the experience of teachers' current use of the online platform (Moodle) in vocational teaching by using a multi-method phenomenographic approach. With data collected by a quantitative survey and in-depth interviews, a complete picture has been developed for the phenomenon being investigated. Findings from the survey and interviews have been used to identify different approaches that teachers can adopt in using Moodle for their vocational subjects in Hong Kong Institute of Vocational Education. Through an iterative process of analysis, numerous issues related to vocational teaching with Moodle are revealed in the research process to extend previous knowledge, including: shift in the vocational teachers' role, adjustment of communication with students, necessity of face-to-face coaching, blended learning, control of the learning progress, preparation of the online content, teaching and learning effectiveness, change of student quality and expectations, and amplified support by the media richness. In addition to analyzing the complexity of the phenomenon, the findings of this research highlight the value of sharing teachers' experience; this provides guidance and insights for other vocational teachers to explore the possibilities and opportunities of using the online platforms in their areas of vocational teaching. Complexity and opportunities have been created, not only for both vocational teachers and students, but also for the stakeholders such as course administrators, curriculum developers, faculty members, educational specialists, and organization leaders considering or using online learning platforms for vocational teaching. Recommendations are given in the conclusion for development of staff capacity and capability in vocational teaching with online platforms, particularly with Moodle. Above all, the results of this research substantiate previous ones in showing the importance of teaching with technology, rather than teaching about technology, or technology for teaching.
198

A political economy of TVET professionalisation : a case study of chefs at a Canadian polytechnic

Loblaw, Timothy J. January 2018 (has links)
This thesis focuses on a political economy analysis of the relationship between the professional identity and professional development practices of instructors in the postsecondary educational sector of technical and vocational education and training (TVET). My study brings together the concept of the dual-professional identity of postsecondary TVET instructors, the practice of professional development in TVET, and a political economy approach. The research methods adapted for this postgraduate research study were from a qualitative perspective using a case study approach. The case study involved eight culinary instructors, the supervisor of the professional cooking programme, and the director of the hospitality and culinary careers school at a postsecondary polytechnic in Canada, selected using a non-probability sampling technique. My research explored what a political economy analysis would reveal about the relationship between the professional identity and the professional development practices of the culinary instructors/chefs. Throughout this thesis, I use the term, TVET professionalisation, to denote this relationship This case study contributes to knowledge and the TVET community in three intersecting ways. Its first contribution is in context - the research took place in the Canadian postsecondary TVET sector, for purposes of analysing the professional identity/professional development relationship in consideration of the historical, structural, and socio-cultural contexts of the institution. The case study's second contribution is in extending the literature of the political economy of skills. The findings demonstrate that analysing the professionalisation of the TVET culinary instructors, in consideration of the inter-relationship among the cultural, economic, political, and social contexts of the TVET system, is a suitable extension of the literature on the political economy of skills. From another perspective, the study also adds to the literature on the professionalisation of TVET instructors by considering professionalisation as an extension of the TVET workforce development imperative, which I note in this study as the discourse promoting employability and the axiomatic assumptions of TVET as 'training-for-growth' and 'skills-for work' (Anderson 2008). Thus, the study contributes to wider debates about the applicability of a political economy analysis beyond skill formation systems. Lastly, the case study contributes a conceptual framework for TVET professionalisation by interpreting the relationship between TVET professional identity and professional development through a political economy lens. The findings demonstrate that both the professional identity and the professional development practices of the culinary instructors in the case study were shaped by various contextual factors within the field of practice: namely, the instructor's personal history and sense of agency, the socio-cultural conventions of the culinary trade under investigation, the social and structural setting of the postsecondary TVET institution, and the workforce development imperative of TVET. The conceptual framework for TVET professionalisation also contributes another perspective toward the dual-professional identity of TVET instructors. Dual-professional identity formation within this study, and drawing upon the language of the research participants, refers to the process where the 'recipe' for the chefs' base identity was written in the professional trade of culinary arts. Once they joined the polytechnic, though, the chefs used the institution as 'stage' to 'go beyond the recipe' and elevate their identities by adding the ingredient of 'becoming an educator'. Based on an interpretation of the case study's findings, through a political economy lens of analysis, I suggest that the 'skilled-educator' identity of the culinary instructors is bound by the structural and socio-economic contexts of the postsecondary polytechnic, whereas the 'skilled-tradesperson' identity of the culinary instructors reflects the historical and socio-cultural contexts of the instructors' lived experience as chefs. Further, I posit that each instructor's perception of meaningful professional development reflects the individual's personal sense of agency; what constitutes both a personal and shared sense of legitimacy concerning the value of professional development; and, an allegiance to one of the dual-professional identities over the other.
199

Algorithms for the analysis of bone marrow cancer histology images

Song, Tzu-Hsi January 2017 (has links)
Automated computer-aided systems and approaches are widely required to investigate and analyze histology images for improving the accuracy of cancer diagnosis and effective treatment decision making. Quantitative analysis has immense potential to investigate and analyze the tissue and cellular characteristics of histology images in cancer research. It is based on accurate cellular, morphological, and tissue features. Automated approaches not only make the feature extraction and analysis more objective and more reproducible, but they can also help pathologists look for useful potential clues from a vast amount of hidden information in cancer tissues, whose clinical value may not be fully realized and visualized. This entails the automated computer algorithms with a key role of quantitative analysis of histology images for different cancers. In this thesis, I concentrate on bone marrow cancers and develop automated computer algorithms to extract and realize cellular and texture characteristics of bone marrow biopsies for efficiently characterizing different types of bone marrow cancers in further investigation and analysis. We focus on the development of automated algorithms for identifying various types of cells in bone marrow trephine biopsies, which are tiny cores of bone marrow tissues. All the algorithms are specifically designed for histological sections stained by a standard hematoxylin and eosin (H&E) stain. Firstly, we propose an automated framework with a novel segmentation model for delineating and segmenting megakaryocytes. Secondly, we create a novel deep learning network that processes the nuclear detection with irregular shape for various types of bone marrow stem cells. Then we construct another synchronized deep learning approach to simultaneously do detection and classification. We demonstrate the effectiveness of the network of detection and classification at same time and the training time consumed in this synchronized network.
200

Modelling immunoglobulin metabolism and its effect on prognostic utility in multiple myeloma

Kendrick, Felicity January 2018 (has links)
Multiple myeloma is a cancer of plasma cells. In multiple myeloma, a clone of plasma cells in the bone marrow secretes a unique, monoclonal immunoglobulin (Ig), whose biological properties depend on its type and structure. The monoclonal Ig offers a convenient opportunity for clinicians to monitor the response of the tumour to therapy via the secreted protein, which is readily quantified in a blood sample. Responses to treatment are assigned based on the percentage reduction in monoclonal Ig; however, response criteria do not take into account the different metabolic half-lives of the proteins. 70% of multiple myeloma patients have either monoclonal IgA- or monoclonal IgG-producing clones. IgA and IgG have metabolic half-lives of 6 days and 23 days, at normal concentrations, respectively. The large difference in their metabolic half-lives suggests that they would respond at different rates during therapy. The elimination rate of IgG is concentration-dependent due to saturable recycling by a receptor. This could further impact upon its response during therapy, with the possibility that IgG is eliminated from the body at different rates at the beginning of therapy, when its concentration is high, and at the end of therapy, when its concentration has decreased. In this thesis compartmental models of IgG metabolism from the literature are analysed and parameter values are estimated from available data. A model of IgA metabolism is sourced in the literature. These models are used to predict the responses of monoclonal IgA and IgG during therapy. The simulations are able to replicate typical monoclonal IgA and IgG responses seen in a clinical trial of patients with relapsed and refractory multiple myeloma. Importantly, the plasma cell clone is not directly accessible to measurement and therefore not available to validate model-based predictions. However, monoclonal Ig responses are not evaluated by their ability to predict the tumour burden, but by the strength of their association with patient survival. In this thesis, a prediction is made of how the different metabolic properties of IgA and IgG may influence their association with survival outcomes. Evidence for this effect is then evaluated in data from a clinical trial using the methods of survival analysis.

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