Ecological similarity plays an important role in biotic interactions. Increased body size similarity of competing species, for example, increases the strength of their biotic interactions. Body sizes of many exothermic species are forecast to be altered under global warming, mediating shifts in existing trophic interactions among species, in particular for species with different thermal niches.
View Article and Find Full Text PDFPurpose: There is a pressing need to investigate the impact of type II diabetes mellitus on the posterior cornea in donor tissues given its increasing prevalence and potential impact on endothelial keratoplasty surgical outcomes.
Methods: Immortalized human cultured corneal endothelial cells (CECs; HCEC-B4G12) were grown in hyperglycemic media for 2 weeks. Extracellular matrix (ECM) adhesive glycoprotein expression and advanced glycation end products (AGEs) in cultured cells and corneoscleral donor tissues, as well as the elastic modulus for the Descemet membrane (DMs) and CECs of diabetic and nondiabetic donor corneas, were measured.
The electrochemical oxidation of small organic molecules (SOMs) such as methanol and glucose is a critical process and has relevant applications in fuel cells and sensors. A key challenge in SOM oxidation is the poisoning of the surface by carbon monoxide (CO) and other partially oxidized intermediates, which is attributed to the presence of Pt-Pt pair sites. A promising pathway for overcoming this challenge is to develop catalysts that selectively oxidize SOMs via "direct" pathways that do not form CO as a primary intermediate.
View Article and Find Full Text PDFGenetic resistance remains a key component in integrated pest management systems. The cosmopolitan root-knot nematode (RKN; spp.) proves a significant management challenge as virulence and pathogenicity vary among and within species.
View Article and Find Full Text PDFChanging climate is forcing many terrestrial and marine species to extend their ranges poleward to stay within the bounds of their thermal tolerances. However, when such species enter higher latitude ecosystems, they engage in novel interactions with local species, such as altered predator-prey dynamics and competition for food. Here, we evaluate the trophic overlap between range-extending and local fish species along the east coast of temperate Australia, a hotspot for ocean warming and species range extensions.
View Article and Find Full Text PDFAs ocean waters warm due to climate change, tropical species are shifting their ranges poleward to remain within their preferred thermal niches. As a result, novel communities are emerging in which tropical species interact with local temperate species, competing for similar resources, such as food and habitat. To understand how range-extending coral reef fish species perform along their leading edges when invading temperate ecosystems, we studied proxies of their fitness, including somatic growth (length increase), feeding rates, and body condition, along a 730-km latitudinal gradient situated in one of the global warming hotspots.
View Article and Find Full Text PDFTranscatheter aortic valve implantation (TAVI) is the treatment of choice for inoperable and high-risk patients with severe aortic stenosis. Our objectives were to elucidate potential differences in clinical outcomes and safety between balloon-expandable versus self-expandable transcatheter heart valves (THV). We performed a retrospective cohort study of all transfemoral TAVI procedures in Ontario, Canada, from 2007 to 2013.
View Article and Find Full Text PDFCatheter Cardiovasc Interv
September 2017
Objective: Our objective was to evaluate sex-differences in outcomes after trans-catheter aortic valve replacement (TAVR) in a population-based cohort from Ontario, Canada.
Background: Prior studies comparing outcomes in men and women after TAVR have yielded divergent results. Some studies have suggested that women have better survival than men while others have not corroborated this finding.
Objective: Transcatheter aortic valve implantation (TAVI) is generally more expensive than surgical aortic valve replacement (SAVR) due to the high cost of the device. Our objective was to understand the patient and procedural drivers of cumulative healthcare costs during the index hospitalisation for these procedures.
Design: All patients undergoing TAVI, isolated SAVR or combined SAVR+coronary artery bypass grafting (CABG) at 7 hospitals in Ontario, Canada were identified during the fiscal year 2012-2013.
Although the appropriate use criteria incorporate common clinical scenarios for coronary revascularization, a significant proportion of patients with stable coronary artery disease (CAD) cannot be assigned an appropriateness score. Our objective was to characterize these patients and to evaluate whether coronary revascularization is associated with improved outcomes. A population-based cohort of patients aged ≥66 years, who underwent cardiac catheterization in Ontario, Canada, were included.
View Article and Find Full Text PDFBackground: The ratio of revascularization to medical therapy (referred to herein as the revascularization ratio) for the initial treatment of stable ischemic heart disease varies considerably across hospitals. We conducted a comprehensive study to identify patient, physician and hospital factors associated with variations in the revascularization ratio across 18 cardiac centres in the province of Ontario. We also explored whether clinical outcomes differed between hospitals with high, medium and low ratios.
View Article and Find Full Text PDFBackground: Radial access is associated with less bleeding and vascular complications. However, it may delay reperfusion during primary percutaneous coronary intervention for ST-segment-elevation myocardial infarction.
Methods And Results: A provincial database prospectively collected clinical and procedural characteristics for all urgent percutaneous coronary intervention procedures performed between June 2010 and September 2011 in Ontario for ST-segment-elevation myocardial infarction, including time of arrival in the catheterization laboratory and time of first balloon inflation.
Background: The use of invasive coronary angiography in stable ischemic heart disease (IHD) varies widely.
Objective: To validate the 2012 appropriate use criteria for diagnostic catheterization by examining the relationship between the appropriateness of cardiac catheterization in patients with suspected stable IHD and the proportion of patients with obstructive coronary artery disease (CAD) and subsequent revascularization.
Design: Population-based, observational, multicenter cohort study.
Background: Wide variation exists in the detection rate of obstructive coronary artery disease (CAD) with elective coronary angiography for suspected stable ischemic heart disease. We sought to understand the incremental impact of nonclinical factors on this variation.
Methods And Results: We included all patients who underwent coronary angiography for possible suspected stable ischemic heart disease, from October 1, 2008, to September 30, 2011, in Ontario, Canada.
Background: The Variation in Revascularization Practice in Ontario (VRPO) project helped describe variations in revascularization across Ontario. Coronary anatomy was the most important predictor of revascularization strategy. We conducted a novel angiographic substudy of the VRPO cohort to: (1) validate "real-world" coronary angiographic reporting in the province of Ontario; and (2) understand the relationship between variability in revascularization and coronary anatomy complexity.
View Article and Find Full Text PDFBackground: Coronary angiograms are important in the diagnostic workup of patients with suspected coronary artery disease. However, little is known about the clinical predictors of normal angiograms and whether this rate varies across different cardiac centers in Ontario.
Methods: We conducted a study using the Cardiac Care Network Variations in Revascularization Practice in Ontario database of 2,718 patients undergoing an index cardiac catheterization for an indication of stable angina between April 2006 and March 2007 at one of 17 cardiac hospitals in Ontario.
Activation of melanocortin 4 receptors (MC4-Rs) in brain nuclei associated with food intake profoundly influences consummatory behavior. Of these nuclei, the dorsal motor vagal nucleus (DMV), which has a dense concentration of MC4-Rs, is an important regulator of gastric tone and motility. Hence, the present study sought to examine the role of MC4-Rs in this nucleus on these activities.
View Article and Find Full Text PDFBackground: Patient and provider-related factors affecting access to cardiac rehabilitation (CR) have been extensively studied, but health-system administration factors have not. The objectives of this study were to investigate hospital administrators' (HA) awareness and knowledge of cardiac rehabilitation (CR), perceptions regarding resources for and benefit of CR, and attitudes toward and implementation of inpatient transition planning for outpatient CR.
Methods: A cross-sectional and observational design was used.
In March of 2010, the Ontario Ministry of Health and Long-term Care and Ontario Medical Association jointly commissioned a Working Group to make recommendations regarding the provision and accreditation of echocardiographic services in Ontario. That commission undertook a process to examine all aspects of the provision, reporting and interpretation of echocardiographic examinations, including the echocardiographic examination itself, facilities, equipment, reporting, indications, and qualifications of personnel involved in the acquisition and interpretation of studies. The result was development of a set of 54 performance standards and a process for accreditation of echocardiographic facilities, initially on a voluntary basis, but leading to a process of mandatory accreditation.
View Article and Find Full Text PDFObjectives: The study assessed the appropriateness of coronary revascularization in Ontario, Canada, and examined its association with longer-term outcomes.
Background: Although appropriate use criteria for coronary revascularization have been developed to improve the rational use of cardiac invasive procedures, it is unknown whether greater adherence to appropriateness guidelines is associated with improved clinical outcomes in stable coronary artery disease.
Methods: A population-based cohort of stable patients undergoing cardiac catheterization was assembled from April 1, 2006, to March 31, 2007.
Background: Multi-disciplinary heart failure (HF) clinics have been shown to improve outcomes for HF patients in randomized clinical trials. However, it is unclear how widely available specialized HF clinics are in Ontario. Also, the service models of current clinics have not been described.
View Article and Find Full Text PDFHealth system stakeholders at different levels are focused more than ever on improvements to quality of care. With heart disease continuing to be a top health issue for Canadians, quality improvement initiatives aimed at improving cardiac care are increasingly important. The Cardiac Care Quality Indicators are one such initiative, with the goal of supporting cardiac care centres in their quality improvement efforts by providing comparable facility-level information on a number of cardiac quality outcome indicators.
View Article and Find Full Text PDFBackground: The ratio of percutaneous coronary interventions to coronary artery bypass graft surgeries (PCI:CABG ratio) varies considerably across hospitals. We conducted a comprehensive study to identify clinical and nonclinical factors associated with variations in the ratio across 17 cardiac centres in the province of Ontario.
Methods: In this retrospective cohort study, we selected a population-based sample of 8972 patients who underwent an index cardiac catheterization between April 2006 and March 2007 at any of 17 hospitals that perform invasive cardiac procedures in the province.
Background: Although cardiac procedures are commonly used to treat cardiovascular disease, they are costly. Administrative data sources could be used to track cardiac procedures, but sources of such data have not been validated against clinical registries.
Objectives: To examine accuracy of cardiac procedure coding in administrative databases versus a prospective clinical registry.