New neurons are generated throughout adulthood in the dentate gyrus of the hippocampus. The aim of the current study was to address whether differences in the morphological complexity of adult-born granule cells affect their integration into existing dentate gyrus circuitry. To selectively label proliferating cells, we injected a CAG-retrovirus into the dentate gyrus of mice. Either 10, 20, 40, or 80 days following viral infection, mice were injected with pentylenetetrazol (PTZ) to induce hippocampal activation, and expression of the immediate early gene c-fos was used as a marker of activated neurons. We then compared morphological features of neurons across age groups and between Fos+ and Fos- neurons within each age group. We found that dendritic length and branch number increased from 10 to 20 days post infection. Unexpectedly, we also found that dendritic length and branch number decreased from 20 to 40 days post infection, suggesting that the maturation of adult-generated neurons is associated with an active pruning process. Furthermore, we found no significant difference in morphological complexity between Fos+ and Fos- neurons, suggesting that dendritic morphology does not influence integration into dentate gyrus circuitry.

Postoperative pain is a major concern to patients undergoing surgical procedures but little research has been conducted on pain management after hospital discharge for orthopaedic patients. Since pain medication is a key component of pain management, it is important to study medication usage from a patient’s perspective, for greater patient–health care provider concordance. A qualitative descriptive approach was taken to investigate the experience of 14 participants with managing pain at home immediately after total knee arthroplasty. Most participants limited their consumption and weaned themselves off prescription analgesics and used over-the-counter pain medications. The participants adapted their regimens in response to several factors and generally were content to self-manage their pain but required access to professional support. The study suggests that when developing postoperative pain management plans, health care providers may need to increase the time they spend addressing patients’ concerns and considering patients’ preferences.

New neurons are generated throughout adulthood in the dentate gyrus of the hippocampus. The aim of the current study was to address whether differences in the morphological complexity of adult-born granule cells affect their integration into existing dentate gyrus circuitry. To selectively label proliferating cells, we injected a CAG-retrovirus into the dentate gyrus of mice. Either 10, 20, 40, or 80 days following viral infection, mice were injected with pentylenetetrazol (PTZ) to induce hippocampal activation, and expression of the immediate early gene c-fos was used as a marker of activated neurons. We then compared morphological features of neurons across age groups and between Fos+ and Fos- neurons within each age group. We found that dendritic length and branch number increased from 10 to 20 days post infection. Unexpectedly, we also found that dendritic length and branch number decreased from 20 to 40 days post infection, suggesting that the maturation of adult-generated neurons is associated with an active pruning process. Furthermore, we found no significant difference in morphological complexity between Fos+ and Fos- neurons, suggesting that dendritic morphology does not influence integration into dentate gyrus circuitry.

Objective: To conduct an open label clinical pilot trial using Ginkgo biloba in the treatment of vitiligo in Toronto to test the feasibility of recruitment, patient retention, variability of outcome measures, identify safety concerns, and magnitude of treatment effect ahead of a full randomized clinical trial. Methods: 12 participants 12 to 35 years old were recruited to a prospective nonrandomized open-label pilot trial and treated with 60 mg of standardized G. biloba BID for 12 weeks. The primary outcome was the validated Vitiligo European Task Force (VETF). Secondary outcomes included the Vitiligo Area Scoring Index (VASI), photographs, and adverse reactions. Results: Ingestion of Ginkgo biloba was associated with a trend towards improvement on VETF measures of vitiligo lesion area and staging, and significant improvement in VETF spread and total VASI vitiligo measures. Conclusions: By achieving full recruitment, showing benefit, and indicating no adverse reactions the pilot study shows that a future RCT is feasible.

Postoperative pain is a major concern to patients undergoing surgical procedures but little research has been conducted on pain management after hospital discharge for orthopaedic patients. Since pain medication is a key component of pain management, it is important to study medication usage from a patient’s perspective, for greater patient–health care provider concordance. A qualitative descriptive approach was taken to investigate the experience of 14 participants with managing pain at home immediately after total knee arthroplasty. Most participants limited their consumption and weaned themselves off prescription analgesics and used over-the-counter pain medications. The participants adapted their regimens in response to several factors and generally were content to self-manage their pain but required access to professional support. The study suggests that when developing postoperative pain management plans, health care providers may need to increase the time they spend addressing patients’ concerns and considering patients’ preferences.

Warfarin has well-proven benefit (stroke prevention) but an associated increase in harm (major bleeding) in patients with atrial fibrillation (AF). Current clinical prediction rules (CPRs) are limited in that stroke CPRs predict only the probabilities of “stroke” and “no stroke” and bleeding CPRs predict only “bleed” and “no bleed” despite the fact that outcomes actually include combinations of these four groups. The study objective was to evaluate methods to create a CPR that calculates individual patient probabilities of warfarin’s four combined benefit/harm outcome groups: i) no stroke/no bleed; ii) no stroke/bleed; iii) stroke/no bleed; iv) stroke/bleed. Methods: Patient-level data were analyzed from a randomized controlled trial database (n=9,155) and an observational anticoagulant clinic database (n=5,475) from start of trial or time of AF diagnosis respectively (baseline), until end of follow-up. Patients were stratified into the four groups based on their outcomes during follow-up. Due to high mortality in both datasets, death was included as an outcome. Decision tree modeling and polytomous logistic regression (PLR) were conducted to identify baseline patient factors predicting each outcome group. Results: Based on a literature review of recent high quality RCTs, benefit and harm are reported separately and not at a more individualized level than subgroup analysis. In this individualized combined benefit/harm analysis, both PLR and decision tree modeling identified predictors of no stroke/no bleed, no stroke/bleed, stroke/no bleed and death without a prior stroke or bleed. PLR results predicted probabilities of combined benefit/harm outcomes for every patient but required detailed computation. However, results could potentially be converted into automated form for ease of use. Decision trees provided a visual algorithm approach to risk assessment but did not i) predict the probability of warfarin’s combined benefit/harm outcomes based on all predictors simultaneously, ii) predict the probability of these outcomes for every patient or iii) provide statistical parameters of predictive value (odds ratios). Conclusions: The PLR technique could be used to predict patient probabilities of combined benefit/harm outcomes with warfarin. The study results require validation, preferably prospectively, in other cohorts. If validated, this approach should be tested to determine if it aids patient decision-making.

In this thesis we are particularly concerned about the development of new and improved influenza vaccines with in the changing external economic environment. The thesis covers two major objectives: 1) Developing methods to estimate the costs of influenza vaccine development The ability to calculate the development costs for specific medicines and vaccines are important to inform investments in innovation. Unfortunately, the literature is predominated by non-reproducible studies only measuring aggregate level drug research and development (R&D) costs. Further, the literature appears very scant on the development costs of new vaccines. In the first objective we therefore describe methodology that improves the transparency and reproducibility of primary indication expected R&D expenditures of influenza vaccines. 2) Developing methods to focus influenza vaccine R&D towards meeting cost-effectiveness targets The second objective is focused on how to forecast evidence requirements for cost effectiveness analysis (CEA) of influenza vaccines. The guidance to manufacturers on what evidence would optimally support acceptable CEA is scant. The absence of such guidance and the increased emphasis on CEA can add significant risk to the vaccine development process. Thus we perform a Value of Information (VOI) analysis on the parameters of a cost effectiveness model designed to evaluate new influenza vaccines designed for use in elderly adults. The results of this study highlight what type of endpoints that should be studied in influenza vaccine R&D programs. From our work on these objectives we are able to shed light on economics that should be considered while developing a new influenza vaccine. Though our contribution is mainly methodological, we conclude the thesis suggesting changes in the way the vaccine industry and HTA agencies work. These changes are in our view necessary to meet society’s demand for new vaccines that deliver high value for money.

In this thesis we are particularly concerned about the development of new and improved influenza vaccines with in the changing external economic environment. The thesis covers two major objectives: 1) Developing methods to estimate the costs of influenza vaccine development The ability to calculate the development costs for specific medicines and vaccines are important to inform investments in innovation. Unfortunately, the literature is predominated by non-reproducible studies only measuring aggregate level drug research and development (R&D) costs. Further, the literature appears very scant on the development costs of new vaccines. In the first objective we therefore describe methodology that improves the transparency and reproducibility of primary indication expected R&D expenditures of influenza vaccines. 2) Developing methods to focus influenza vaccine R&D towards meeting cost-effectiveness targets The second objective is focused on how to forecast evidence requirements for cost effectiveness analysis (CEA) of influenza vaccines. The guidance to manufacturers on what evidence would optimally support acceptable CEA is scant. The absence of such guidance and the increased emphasis on CEA can add significant risk to the vaccine development process. Thus we perform a Value of Information (VOI) analysis on the parameters of a cost effectiveness model designed to evaluate new influenza vaccines designed for use in elderly adults. The results of this study highlight what type of endpoints that should be studied in influenza vaccine R&D programs. From our work on these objectives we are able to shed light on economics that should be considered while developing a new influenza vaccine. Though our contribution is mainly methodological, we conclude the thesis suggesting changes in the way the vaccine industry and HTA agencies work. These changes are in our view necessary to meet society’s demand for new vaccines that deliver high value for money.

Colorectal cancer is the second leading cause of death from cancer (men and women combined) in the U.S. and Canada. The mainstay of treatment remains surgical resection and although new agents are constantly emerging to treat colorectal cancer, to date none of the agents have been successful at curing patients with advanced disease. In recent years there has been an increasing interest in the notion that cancers are organized as a hierarchy with the cancer-initiating cell (C-IC or cancer stem cell) existing at the apex. The C-ICs only represent a subset of the total tumour cells; however, research indicates that they are responsible for both the initiation and maintenance of tumour growth. In the studies presented here, we determined that human colon cancers are organized in a hierarchical manner. Furthermore, we prospectively isolated a subset of colon cancer-initiating cells (CC-ICs) based on the expression of the cell surface marker, CD133. The identification of CC-ICs has led to a number of questions concerning the molecular mechanisms driving these cells. Functionally all C-ICs are characterized by their ability to: i) generate a xenograft that histologically resembles the parent tumour from which it was derived, (ii) be serially transplanted in a xenograft assay thereby demonstrating the ability to self-renew and, (iii) generate daughter cells that possess some proliferative capacity but are unable to maintain the cancer because they lack intrinsic regenerative potential. It is becoming evident that cancer cells evolve as a result of their ability to hijack normal self-renewal pathways, a process that can drive malignant transformation. Studying self-renewal in the context of cancer and C-IC maintenance will lead to a better understanding of the mechanisms driving tumour growth. In this work we demonstrate that the inhibitors of differentiation genes (Id1 and Id3) play a central role in driving self-renewal in the CC-IC subset. Furthermore, we demonstrate that this effect is partially mediated through the cdk-inhibitor, p21cip1/waf1.

Colorectal cancer is the second leading cause of death from cancer (men and women combined) in the U.S. and Canada. The mainstay of treatment remains surgical resection and although new agents are constantly emerging to treat colorectal cancer, to date none of the agents have been successful at curing patients with advanced disease. In recent years there has been an increasing interest in the notion that cancers are organized as a hierarchy with the cancer-initiating cell (C-IC or cancer stem cell) existing at the apex. The C-ICs only represent a subset of the total tumour cells; however, research indicates that they are responsible for both the initiation and maintenance of tumour growth. In the studies presented here, we determined that human colon cancers are organized in a hierarchical manner. Furthermore, we prospectively isolated a subset of colon cancer-initiating cells (CC-ICs) based on the expression of the cell surface marker, CD133. The identification of CC-ICs has led to a number of questions concerning the molecular mechanisms driving these cells. Functionally all C-ICs are characterized by their ability to: i) generate a xenograft that histologically resembles the parent tumour from which it was derived, (ii) be serially transplanted in a xenograft assay thereby demonstrating the ability to self-renew and, (iii) generate daughter cells that possess some proliferative capacity but are unable to maintain the cancer because they lack intrinsic regenerative potential. It is becoming evident that cancer cells evolve as a result of their ability to hijack normal self-renewal pathways, a process that can drive malignant transformation. Studying self-renewal in the context of cancer and C-IC maintenance will lead to a better understanding of the mechanisms driving tumour growth. In this work we demonstrate that the inhibitors of differentiation genes (Id1 and Id3) play a central role in driving self-renewal in the CC-IC subset. Furthermore, we demonstrate that this effect is partially mediated through the cdk-inhibitor, p21cip1/waf1.