26 research outputs found

    Style in music seen as restraint : an information theory approach

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    Note:The subject of this thesis is the application of information theory to the analysis and composition of music. Designed as an introduction to the theory for the musician, the initial sections of the thesis describe six concepts from information theory selected for their value in musical application. These are information, stochastic process (including ergodic sources and Markov chains), entropy, redundancy, channel capacity and noise. The next sections describe the range of existing applications and the concluding sections deal with the criticisms of such applications. As illustration, demonstrations of information theory analysis and generation are offered, including an original tape composition based on the principles outlined in this thesis.Le sujet de cette thèse applique la théorie d’information à l'analyse et à la composition de la musique. Les sections initiales de la thèse introduisent le musicien à la théorie; elles décrivent six concepts de la théorie d'information choisis pour leur valeur dans l'application musicale. Ceux-ci comprennent l'information, le processus "stochastic" (incluant les sources "ergodic" et les chaines Markov), l'entropie, la redondance, la capacité du canal et le bruit. Les sections qui suivent décrivent le champ des applications existantes et les sections conclusives traitent des critiques se rapportant à de telles applications. Comme illustration, les démonstrations de la théorie d'information, se rapportant à l’analyse et à la génération, sont présentées l’incluant l'original d'une composition sur bande magnétique, basé sur les principes énoncés dans cette thèse

    The Pathway for New Cancer Drug Access in Canada

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    Cancer treatment has evolved significantly over the past decade with the emergence of a multitude of new treatments across cancer types. Alongside the pace of drug discovery, the cost of cancer drugs has also increased. In the face of this growth in development and spending, it is crucial to have an understanding of the processes and pressures new drugs navigate to get to the market in Canada. This paper is a review of the complex, multi-step regulatory and funding process undertaken by cancer drugs in Canada. It reviews the role of Health Canada, the Patented Medicine Prices Review Board, the Health Technology Assessment, the pan-Canadian Pharmaceutical Alliance, and finally, the provincial, territorial, and federal payers. Recent developments are highlighted. Strategies to minimize duplication of effort, improve timeliness, and increase efficiency are explored. The cancer drug regulatory and funding process in Canada is complex, and an understanding of the current system and ongoing evolution is essential

    Determinants of the Cancer Drug Funding Process in Canada

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    Background: Canada has a publicly funded healthcare system with a complex drug funding process. After Health Canada approval to market a drug, the pan-Canadian Oncology Drug Review (pCODR) (now renamed the CADTH reimbursement review) makes a non-binding funding recommendation to the Canadian provinces (except Quebec), which each then decide whether the drug will be publicly funded. We identified the determinants of funding in this process. Methods: We analyzed drugs for advanced lung (n = 15), breast (n = 8), colorectal (CRC) (n = 7), melanoma (n = 10), and neuroendocrine (NET) (n = 3) cancers undergoing the funding decision process from 2011 to 2019. Determinants of funding assessed in the model included list price, cancer type, drug class, and pCODR recommendation. The primary outcome was the correlation between list price and time to funding (TTF: Health Canada approval to first provincial funding). Secondary outcomes included an exploratory analysis of predictors of drug funding. Results: We analyzed 43 drugs: targeted agents 72%, immunotherapy 20%, chemotherapy 7%. A total of 72% were funded in at least one province. Median TTF was 379 days (IQR 203–601). Median list price (28-day course) was CAD 8213 (IQR CAD 5391–9445). Higher list price was not correlated with TTF (correlation coefficient −0.20, p = 0.28). There was no association between list price and pCODR recommendation or the decision to fund in at least one province. A positive pCODR recommendation correlated with the provinces’ funding decisions (p < 0.001), where 89% of drugs with a positive recommendation were funded and 100% of drugs with a negative recommendation were not funded. Tumor type was predictive of TTF (p < 0.001): CRC drugs were the slowest at a median of 2541 days (IQR 702–4379), and NETs were the quickest at a median of 0 days (IQR 0–502). Cancer type predicted decision to fund in at least one province (p = 0.005), with funding for 100% of NET drugs at the high end and 29% of CRC drugs at the low end. Drug class was predictive of TTF (p = 0.01): 465 days (IQR 245–702) for targeted agents, 443 days (IQR 298–587) for chemotherapy, and 339 days (IQR 164–446) for immunotherapy. Conclusions: Determinants of drug funding included cancer type, drug class, and pCODR recommendation but not list price. Factors other than cost were more heavily weighted in the funding decisions of cancer drugs in Canadian provinces

    Epidermal Growth Factor Receptor Inhibitor–Induced Hypomagnesemia: A Survey of Practice Patterns among Canadian Gastrointestinal Medical Oncologists

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    Background: The optimal management of hypomagnesemia (hMg) induced by epidermal growth factor receptor inhibitors (EGFRIS) for advanced colorectal cancer is unclear. We surveyed gastrointestinal medical oncologists in Canada to determine practice patterns for the management of EGFRI-induced hMg. Methods: Based on distribution lists from the Eastern Canadian Colorectal Cancer Consensus Conference and the Western Canadian Gastrointestinal Cancer Consensus Conference, medical oncologists were invited to participate in an online questionnaire between November 2013 and February 2014. Results: From the 104 eligible physicians, 40 responses were obtained (38.5%). Panitumumab was more commonly prescribed than cetuximab by 70% of respondents, with 25% prescribing cetuximab and panitumumab equally. Most respondents obtain a serum magnesium level before initiating a patient on an EGFRI (92.5%) and before every treatment (90%). Most use a reactive strategy for magnesium supplementation (90%) and, when using supplementation, favour intravenous (IV) alone (40%) or IV and oral (45%) dosing. Magnesium sulfate was used for IV replacement, and the most common oral strategies were magnesium oxide (36.4%) and magnesium rougier (18.2%). Under the reactive strategy, intervention occurred at hMg grade 1 (70.3%) or grade 2 (27%). Of the survey respondents, 45% felt that 1–5 of their patients have ever developed symptoms attributable to hMg, and 35% have had to interrupt EGFRI therapy because of this toxicity, most commonly at grade 3 (30%) or grade 4 (45%) hMg. The most important question about EGFRI-induced hMg was its relevance to clinical outcomes (45%) and its symptoms (37.5%). Conclusions: In Canada, various strategies are used in the management of EGFRI-induced hMg, including prophylactic and reactive approaches that incorporate IV, oral, or a combination of IV and oral supplementation. Clinicians are concerned about the effect of hMg on clinical outcomes and about the symptoms that patients experience as a result of this toxicity

    Real-Life Treatment of Metastatic Colorectal Cancer with Regorafenib: A Single-Centre Review

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    Background: Various tyrosine kinase signalling pathways affect the development and progression of colorectal cancer (crc). In clinical trials, regorafenib has been associated with a survival benefit in metastatic crc (mcrc). We assessed the safety and efficacy of regorafenib in real-world patients. Methods: In a retrospective review of patients with mcrc treated with regorafenib at our institution from 2013 to 2015, patient demographics, treatment, and survival data were collected. Progression-free survival (pfs) and overall survival (os) were estimated using the Kaplan–Meier method. Results: In total, 48 patients were offered regorafenib, and 35 (73%) started treatment. Of the patients who started regorafenib, 57% were men. Median age in the cohort was 61 years, and all patients had a performance status in the range 0–2. Time from diagnosis of mcrc to regorafenib treatment was more than 18 months in 71% of patients. Starting dose was 160 mg in 54% of the patients, 120 mg in 40%, and 80 mg in 6%. Dose reductions occurred in 34% of the patients, and interruptions, in 29%. Best response was progressive disease (60%) and stable disease (17%); response in the rest of the patients was unknown. The most common adverse events on regorafenib (any grade) were fatigue (57%), hyperbilirubinemia (43%), thrombocytopenia (37%), anorexia (31%), and hypertension (31%). The most common grade 3 or 4 adverse events were fatigue (29%), hypophosphatemia (17%), weight loss (11%), and hyperbilirubinemia (9%). Common reasons for discontinuing regorafenib included progressive disease (51%) and toxicity (26%). In patients treated with regorafenib, pfs was 2.4 months (95% confidence interval: 1.8 to 3.3 months) and os was 5.6 months (95% confidence interval: 3.7 to 8.9 months). No factors were associated with survival in univariate or multivariate analysis. Conclusions: In a real-world setting, regorafenib is associated with survival similar to that reported in the randomized controlled trials, but at the expense of toxicity leading to discontinuation in many patients. Future studies of regorafenib should focus on identifying the patients most likely to benefit and on minimizing toxicity

    Therapeutic inhibition of miR-33 promotes fatty acid oxidation but does not ameliorate metabolic dysfunction in diet-induced obesity

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    Objective— miR-33 has emerged as an important regulator of lipid homeostasis. Inhibition of miR-33 has been demonstrated as protective against atherosclerosis; however, recent studies in mice suggest that miR-33 inhibition may have adverse effects on lipid and insulin metabolism. Given the therapeutic interest in miR-33 inhibitors for treating atherosclerosis, we sought to test whether pharmacologically inhibiting miR-33 at atheroprotective doses affected metabolic parameters in a mouse model of diet-induced obesity. Approach and Results— High-fat diet (HFD) feeding in conjunction with treatment of male mice with 10 mg/kg control anti-miR or anti-miR33 inhibitors for 20 weeks promoted equivalent weight gain in all groups. miR-33 inhibitors increased plasma total cholesterol and decreased serum triglycerides compared with control anti-miR, but not compared with PBS-treated mice. Metrics of insulin resistance were not altered in anti-miR33–treated mice compared with controls; however, respiratory exchange ratio was decreased in anti-miR33–treated mice. Hepatic expression of miR-33 targets Abca1 and Hadhb were derepressed on miR-33 inhibition. In contrast, protein levels of putative miR-33 target gene SREBP-1 or its downstream targets genes Fasn and Acc were not altered in anti-miR33–treated mice, and hepatic lipid accumulation did not differ between groups. In the adipose tissue, anti-miR33 treatment increased Ampk gene expression and markers of M2 macrophage polarization. Conclusions— We demonstrate in a mouse model of diet-induced obesity that therapeutic silencing of miR-33 may promote whole-body oxidative metabolism but does not affect metabolic dysregulation. This suggests that pharmacological inhibition of miR-33 at doses known to reduce atherosclerosis may be a safe future therapeutic
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