Background: The "small phylogeny" problem consists in inferring ancestral genomes associated with each internal node of a phylogenetic tree of a set of extant species. Existing methods can be grouped into two main categories: the distance-based methods aiming at minimizing a total branch length, and the synteny-based (or mapping) methods that first predict a collection of relations between ancestral markers in term of "synteny", and then assemble this collection into a set of Contiguous Ancestral Regions (CARs). The predicted CARs are likely to be more reliable as they are more directly deduced from observed conservations in extant species.
View Article and Find Full Text PDFGiven a phylogenetic tree involving whole genome duplication events, we contribute to solving the problem of computing the rearrangement and double cut-and-join (DCJ) distances on a branch of the tree linking a duplication node d to a speciation node or a leaf s. In the case of a genome G at s containing exactly two copies of each gene, the genome halving problem is to find a perfectly duplicated genome D at d minimizing the rearrangement distance with G. We generalize the existing exact linear-time algorithm for genome halving to the case of a genome G with missing gene copies.
View Article and Find Full Text PDFObjectives: In light of recent results from observational studies showing prolonged survival in subjects taking long-acting beta2-agonists (LABA) and/or inhaled corticosteroids (ICS) for chronic obstructive pulmonary disease (COPD), we investigated their cost-effectiveness (CE).
Methods: Costs and survival data were collected for a sample of members enrolled in a large Health Maintenance Organization in the United States. An observational study design was used to evaluate cumulative costs and health benefits of LABA, ICS, ICS+LABA, or comparison drugs.
Goals: To estimate resource use and expected annual cost of care for subjects with chronic hepatitis B and resulting complications in Canada.
Background: Patients chronically infected with hepatitis B virus are at an increased risk of progressing to complications from deteriorating liver function.
Study: The direct medical costs for six disease states associated with chronic hepatitis B virus infection were estimated for the year 2001.
Purpose: This pilot study was designed to test the hypothesis that the use of a single oral splint may aggravate respiratory disturbance in sleep apneic patients.
Materials And Methods: A group of 10 patients with a history of snoring and a recording night confirming a diagnosis of sleep apnea were included. Patients were then invited to spend 2 nights in the sleep laboratory: night 2 to establish baseline data (baseline night) and night 3, 1 week later, to assess the influence of an occlusal maxillary splint on sleep (splint night).
Objectives: Administering proton pump inhibitors (PPI) intravenously (iv) after endoscopic treatment of bleeding peptic ulcers reduces the incidence of rebleeding, the need for operative procedures, and hospitalizations. We assessed the cost implications of iv PPI initiated in all patients presenting to the emergency department (ED) with signs of upper gastrointestinal (UGI) bleeding.
Methods: From a third-party payer perspective with a time horizon of 60 days, we built a decision analytic model comparing standard endoscopic therapy to a strategy in which all patients presenting to the ED with UGI bleeding would start iv PPI before endoscopy.
The fiscal "cat" of healthcare spending - drug expenditures - is out of the bag: drug costs are now the fastest rising component of healthcare expenditures in Canada. Laupacis, Anderson and O'Brien describe the current process of listing drugs on the provincial drug formulary in Ontario, identify factors that may contribute to the rapid growth in drug expenditures, and make a number of recommendations for controlling drug expenditures, including (1) improving the evidence on cost-effectiveness; (2) disseminating the evidence to prescribers; (3) re-evaluating the evidence; and (4) increasing the transparency about the acquisition costs of drugs. These are recommendations that, if implemented, would theoretically help decision-makers make more rational decisions about which drugs to list on provincial formularies.
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