The domestic dog, Canis lupus familiaris, has emerged as a model system for the study of human hereditary diseases. Of the approximately 450 hereditary diseases described in the dog, half have clinical presentations that are quite similar to specific human diseases. Understanding the genetic bases of canine hereditary diseases will not only complement comparative genetics studies but also facilitate selective breeding practices to reduce incidences in the dog. Whole genome screens have great potential to identify the marker(s) that segregate with canine hereditary diseases for which no reasonable candidate genes exist. The Minimal Screening Set-1 (MSS-1) was the first set of microsatellite markers described for linkage analysis in the dog and was, until recently, the best tool for genome screens. The MSS-2 is the most recently described screening set and offers increased density and more polymorphic markers. The first objective of this work was to develop tools to streamline genomic analyses in the study of canine hereditary diseases. This was achieved through the development of 1) multiplexing strategies for the MSS-1, 2) a multiplex of microsatellite markers for use in canine forensics and parentage assays and 3) chromosome-specific multiplex panels for the MSS-2. Multiplexing is the simultaneous amplification and analysis of markers and significantly reduces the expense and time required to collect genotype information. Pancreatic acinar atrophy (PAA) is a disease characterized by the degeneration of acinar cells of the exocrine pancreas and is the most important cause of exocrine pancreatic insufficiency (EPI) in the German Shepherd Dog (GSD). Although the prognosis for dogs having EPI is typically good with treatment, many dogs are euthanized because the owners are unable to afford the expensive enzyme supplements. The second objective of this work was to determine the mode of transmission of EPI in the GSD and conduct a whole genome screen for linkage. Two extended families of GSDs having PAA were assembled and used to determine the pattern of transmission. The results of this indicate that PAA is an autosomal recessive disease. The multiplexed MSS-1 was used to conduct an initial whole genome screen, although no markers were suggestive of linkage.

No description available.

A method was developed to produce and incorporate a network of discrete, genipin-crosslinked gelatin microfibers around a pancreatic islet within a barium alginate microcapsule. This technique allows for the encapsulation of a porous fibrous matrix without the geometrical restrictions required for cellular aggregate seeding. Microfibers were produced from a novel vortex-drawn extrusion system with an alginate support matrix. Optimization culminated in a hydrated fiber diameter of 22.3 ± 0.4 μm, a 98% reduction in cross sectional area, while making the process more reliable and less labour intensive. The optimized microfibers were encapsulated at 40 vol% within 294 ± 4 μm 1.6% barium alginate microparticles by an electrostatic-mediated dropwise extrusion system. Pancreatic islets extracted from Sprague Dawley rats were encapsulated within the microparticles, and analyzed over a 21-day preliminary in vitro study. Acridine orange and propidium iodide fluorescent viability staining and light microscopy indicated a significant increase in viability for the fiber-laden particles relative to fiber-free control particles at days 7, 14, and 21. The fiber-laden system also reduced the incidence of disrupted islet cohesion from 31% to 8% at day 21, and showed evidence of islet-fiber adhesion. Preliminary investigations into insulin secretion and metabolic activity showed no significant difference between test and control groups. Further investigation into benefits of islet encapsulation within an extracellular matrix fiber network will be the subject of future studies with this body of work serving as a foundation. The system developed in this investigation could be developed into a modular scaffold system for tissue engineering beyond the field of islet research. / Thesis (Master, Chemical Engineering) -- Queen's University, 2011-08-18 15:05:50.917

Our objective was to examine the impact of palliative care (PC) on aggressive care near death for patients with advanced pancreatic cancer. Measures of aggressive care included (i) chemotherapy within 14 days of death; (ii) more than one emergency department (ED) visit; (iii) more than one hospitalization; and (iv) at least one intensive care unit (ICU) admission, all within 30 days of death. A retrospective population-based cohort study was conducted with patients diagnosed with advanced pancreatic cancer in Ontario. Multivariable logistic analyses were performed. Our final cohort consisted of 5,381 patients (median survival of 75 days). 52% received a PC consultation. PC consultation was associated with decreased use of chemotherapy near death (OR=0.34); and lower risk of ICU admission (OR=0.12), multiple ED visits (OR=0.19), and multiple hospitalizations near death (OR=0.24). A per unit increase in the monthly rate of PC visits was associated with lower odds of aggressive care.

Our objective was to examine the impact of palliative care (PC) on aggressive care near death for patients with advanced pancreatic cancer. Measures of aggressive care included (i) chemotherapy within 14 days of death; (ii) more than one emergency department (ED) visit; (iii) more than one hospitalization; and (iv) at least one intensive care unit (ICU) admission, all within 30 days of death. A retrospective population-based cohort study was conducted with patients diagnosed with advanced pancreatic cancer in Ontario. Multivariable logistic analyses were performed. Our final cohort consisted of 5,381 patients (median survival of 75 days). 52% received a PC consultation. PC consultation was associated with decreased use of chemotherapy near death (OR=0.34); and lower risk of ICU admission (OR=0.12), multiple ED visits (OR=0.19), and multiple hospitalizations near death (OR=0.24). A per unit increase in the monthly rate of PC visits was associated with lower odds of aggressive care.

No description available.

A thorough understanding of beta-cell proliferation, function, death and regeneration under normal condition as well as in the progression of diabetes is crucial to the conquest of this disease. The work presented in this thesis aimed to investigate the expression and role of a novel transcription factor, Zinc finger BED domain-containing protein 6 (ZBED6), in beta-cells. ZBED6 was present in mouse βTC-6 cells and human islets as a double nuclear band at 115/120 kDa and as a single cytoplasmic band at 95-100 kDa, which lacked N-terminal nuclear localization signals. Lentiviral shRNA-mediated stable silencing of ZBED6 in βTC-6 cells resulted in altered morphology, decreased proliferation, a partial S/G2 cell cycle arrest, increased expression of beta-cell specific genes, and higher rates of apoptosis. ChIP sequencing of human islets showed that ZBED6 binding was preferentially to genes that control transcription, macromolecule biosynthesis and apoptosis. We proposed that ZBED6 supported proliferation and survival of beta-cells, possibly at the expense of specialized beta-cell function, i.e. insulin production. To further investigate the role of ZBED6 in beta-cells, ChIP sequencing and whole transcriptome analysis were performed using MIN6 cells. More than 4000 putative target genes of ZBED6 were identified, including Pdx1, MafA and Nkx6.1. ZBED6-silencing resulted in differential expression of more than 700 genes, which was paralleled by an increase in the content and release of insulin in response to a high glucose concentration. Altered morphology/growth patterns as indicated by increased cell clustering were observed in ZBED6 silenced cells. We found also that ZBED6 decreased the ratio between N- and E-cadherin. A lower N- to E-cadherin ratio may hamper the formation of three-dimensional beta-cell clusters and cell-to-cell junctions with neural crest stem cells, and instead promote efficient attachment to a laminin support and monolayer growth. Thus, by controlling beta-cell adhesion and cell-to-cell junctions, ZBED6 might play an important role in beta-cell differentiation, proliferation and survival.

Pancreatic adenocarcinoma (PDAC) putatively arises from the pancreatic duct, thus usage of the normal human pancreatic duct epithelial (HPDE) cell line is an ideal model to examine the successive accumulation of genetic alterations involved in carcinogenesis. KRAS mutations have been reported in 90% of PDACs. Oncogenic KRAS elicits activation of downstream pathways involved in survival, motility, and cell cycle progression. KRASG12V introduction in the HPDE cell line upregulates Lipocalin-2 (LCN2) expression. LCN2 has been identified in numerous carcinomas and is associated with survival, tumorigenicity, and invasion. In this work, LCN2 was found to be commonly expressed in high grade pancreatic duct neoplastic precursor lesions and PDAC illustrating its potential as a biomarker. Moreover, in vitro and in vivo studies demonstrate that high LCN2 expression promotes gemcitabine resistance, MMP-9 activity, angiogenesis, and tumorigenicity. Loss of Smad4 function is found in 55% of PDAC cases. Smad4 is a critical component in the TGF-β signaling which mediates the transcription of genes involved in processes such as cell cycle arrest, apoptosis, and invasion. This work examined the consequences of KRASG12V expression and Smad4 loss in the HPDE model. Cellular invasion was promoted by KRASG12V expression or knocking down Smad4 by 80% in the HPDE model. A TGF-β resistant HPDE cell line, TβR, was shown to lack Smad4 expression due to deletion, promoter methylation, and nonsense mutation. KRASG12V expression in the TβR model (TβR KRAS) promoted neoplastic transformation and tumour formation in immunodeficient mice with complete penetrance. Smad4 expression in the TβR KRAS cell line reinstated TGF-β signaling, delayed tumour formation, and decreased metastatic spread. This study provides evidence that Smad4 acts as a restriction point in the transformation of HPDE cells. Overall, this work examines the contribution of genes involved in transformation, and identifies a potential therapeutic and diagnostic biomarker in PDAC.

No description available.

Severe and progressive weight loss is a feature of pancreatic cancer but it has been unclear whether dietetic intervention can improve patient outcomes. This study is a post hoc analysis of the extensive data available from the multicentre BH80 Cancer Cachexia trial to examine how patients with unresectable pancreatic cancer respond to intensive dietetic intervention. The BH80 study compared an n-3 fatty acid enriched oral supplement with an isonitrogenous, isocaloric supplement given over an eight week period. Additional qualitative data was also collected and examined for the patients recruited by the Australian sites. The aims were to determine whether achieving weight stabilisation is an appropriate goal of nutrition intervention for people with unresectable pancreatic cancer; to identify determinants of weight stabilisation; and to describe nutrition-related features of patients recruited by the Australian sites, prior to and during intensive nutrition intervention. Data from 107 patients for whom weight change data over an eight week nutrition intervention period was available, was divided into weight losing (less than 1kg lost) and weight stable (less than or equal to 1 kg lost) patients. Group survival duration (Kaplan Meier log rank test) and global quality of life (EORTC QLQ-C30 global health status/quality of life) were compared. Variables including energy intake, BMI, presence of pain, nausea and vomiting, and appetite loss, C reactive protein and stage of disease were also compared to determine predictors of weight stability using logistic regression analysis. This study demonstrates that weight stabilisation is not only achievable for some patients in the short term, but it is also associated with improved outcomes. Those patients who were able to stabilise their weight after eight weeks of oral nutrition support lived longer from baseline and reported better quality of life than those who continued to lose weight. Weight stabilisation is therefore a reasonable and worthwhile goal for this patient group.