The Impact of Climate Change on the Food System in Toronto.

As part of its Climate Change and Health Strategy, in 2017, Toronto Public Health engaged stakeholders from across the food system to complete a high-level vulnerability assessment of the impact of climate change on the food system in Toronto. Using the Ontario Climate Change and Health Vulnerability and Adaptation Assessment Guidelines, the City of Toronto's High-Level Risk Assessment Tool, and a strategic framework developed by the Initiative for a Competitive Inner City, Toronto Public Health identified the most significant extreme weather event risks to food processing, distribution and access in Toronto. Risks associated with three extreme weather events that are the most likely to occur in Toronto due to climate change were analyzed: significant rain and flooding, an extended heat wave, and a major winter ice storm.

A combined emission and receptor-based approach to modelling environmental noise in urban environments.

The state of practice for noise assessment utilizes established standards for emission and propagation modelling of linear and point sources. Recently, land use regression (LUR) modelling has emerged as an alternative method due to relatively low data and computing resource demands. However, a limitation of LUR modelling is that is does not account for noise attenuation and reflections by features of the built environment.

Development of a guide to applying precaution in local public health.

Purpose: The precautionary principle (PP) urges actions to prevent harm even in the face of scientific uncertainty. Members of Toronto Public Health (TPH) sought guidance on applying precaution.

Methods: We searched five bibliographic databases (yield 60 articles from 1996 to 2009 and 8 from 2009 to 2011) and Google (yield 11 gray literature sources) for material relevant to local public health.

Healthy Toronto by Design: Promoting a healthier built environment.

Chronic diseases, obesity and sedentary lifestyles are some of the health challenges facing Canada today. There is increasing recognition and evidence that the way our cities are planned, designed and built can contribute to these problems. Many of the policy levers to address the built environment exist outside the health sector and at the municipal level in areas such as urban planning, transportation, parks and recreation, and housing.

Novel lipoprotein density profiling in healthy dogs of various breeds, healthy Miniature Schnauzers, and Miniature Schnauzers with hyperlipidemia.

Background: Despite the importance of abnormalities in lipoprotein metabolism in clinical canine medicine, the fact that most previously used methods for lipoprotein profiling are rather laborious and time-consuming has been a major obstacle to the wide clinical application and use of lipoprotein profiling in this species. The aim of the present study was to assess the feasibility of a continuous lipoprotein density profile (CLPDP) generated within a bismuth sodium ethylenediaminetetraacetic acid (NaBiEDTA) density gradient to characterize and compare the lipoprotein profiles of healthy dogs of various breeds, healthy Miniature Schnauzers, and Miniature Schnauzers with primary hypertriacylglycerolemia. A total of 35 healthy dogs of various breeds with serum triacylglycerol (TAG) and cholesterol concentrations within their respective reference intervals were selected for use as a reference population.

Human HDL containing a novel apoC-I isoform induces smooth muscle cell apoptosis.

Aims: We discovered that some adults with coronary heart disease (CHD) have a high density lipoprotein (HDL) subclass which induces human aortic smooth muscle cell (ASMC) apoptosis in vitro. The purpose of this investigation was to determine what properties differentiate apoptotic and non-apoptotic HDL subclasses in adults with and without CHD.

Methods And Results: Density gradient ultracentrifugation was used to measure the particle density distribution and to isolate two HDL subclass fractions, HDL2 and HDL3, from 21 individuals, including 12 without CHD.

Mobilization of ectopic yolk in Gallus gallus domesticus: a novel reverse lipid transport process.

In many oviparous animals, bursting type atresia of ovarian follicles occurs during the reproductive cycle, resulting in the escape of yolk into the extracellular compartment. In birds, this ectopic yolk is rapidly cleared by an unknown process that involves the appearance of yolk-engorged macrophage-like cells. To study this unique type of lipid transport, we injected young male chickens intra-abdominally with egg yolk.

Developing high performance lipoprotein density profiling for use in clinical studies relating to cardiovascular disease.

Early detection of the beginning stage of cardiovascular disease (CVD) is an approach to prevention because the process is reversible at this stage. Consequently, several methods for screening for CVD have been introduced in recent years incorporating different analytical methods for characterizing the population of blood-borne lipoprotein subclasses. The gold standard method for lipoprotein subclassification is based on lipoprotein density measured by sedimentation equilibrium using the ultracentrifuge.

Isoforms of apolipoprotein C-I associated with individuals with coronary artery disease.

Apolipoprotein C-I (apoC-I) is a 6.6kDa serum protein associated with high density lipoproteins (HDL) and triglyceride-rich lipoproteins. In this study, apoC-I was examined in high density lipoprotein subfractions from individuals with and without coronary artery disease (CAD).

Effect of sterol carrier protein-2 gene ablation on HDL-mediated cholesterol efflux from cultured primary mouse hepatocytes.

Although HDL-mediated cholesterol transport to the liver is well studied, cholesterol efflux from hepatocytes back to HDL is less well understood. Real-time imaging of efflux of 22-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-amino)-23,24-bisnor-5-cholen-3beta-ol (NBD-cholesterol), which is poorly esterified, and [(3)H]cholesterol, which is extensively esterified, from cultured primary hepatocytes of wild-type and sterol carrier protein-2 (SCP-2) gene-ablated mice showed that 1) NBD-cholesterol efflux was affected by the type of lipoprotein acceptor, i.e.

Overexpression of sterol carrier protein-2 differentially alters hepatic cholesterol accumulation in cholesterol-fed mice.

Although in vitro studies suggest a role for sterol carrier protein-2 (SCP-2) in cholesterol trafficking and metabolism, the physiological significance of these observations remains unclear. This issue was addressed by examining the response of mice overexpressing physiologically relevant levels of SCP-2 to a cholesterol-rich diet. While neither SCP-2 overexpression nor cholesterol-rich diet altered food consumption, increased weight gain, hepatic lipid, and bile acid accumulation were observed in wild-type mice fed the cholesterol-rich diet.

UC/MALDI-MS analysis of HDL; evidence for density-dependent post-translational modifications.

The purpose of this study is to determine whether the nature of the post-translational modifications of the major apolipoproteins of HDL is different for density-distinct subclasses. These subclasses were separated by ultracentrifugation using a novel density-forming solute to yield a high-resolution separation. The serum of two subjects, a control with a normolipidemic profile and a subject with diagnosed cardiovascular disease, was studied.

Anatomy of heat waves and mortality in Toronto: lessons for public health protection.

Background: Periods of unusually hot weather, especially in temperate climates, carry with them a burden of morbidity and mortality, particularly in urban areas. With lessening debate on its origins, and signs of global warming already apparent, it is becoming imperative for public health practitioners to recognize and predict the risks of "heat waves", and to develop protective community responses to them. This study makes use of historical data and a methodology developed previously to examine the pattern of hot weather experienced over the last five decades in the City of Toronto, and to assess the associated burden of mortality.

Electronegative LDLs from familial hypercholesterolemic patients are physicochemically heterogeneous but uniformly proapoptotic.

A highly electronegative fraction of human plasma LDLs, designated L5, has distinctive biological activity that includes induction of apoptosis in bovine aortic endothelial cells (BAECs). This study was performed to identify a relationship between LDL density, electronegativity, and biological activity, namely, the induction of apoptosis in BAECs. Plasma LDLs from normolipidemic subjects and homozygotic familial hypercholesterolemia subjects were separated into five subfractions, with increasing electronegativity from L1 to L5, and into seven subfractions according to increasing density, D1 to D7.

Remnant lipoprotein density profiling by CsBiEDTA density gradient ultracentrifugation.

Remnant lipoproteins (RLPs) are now considered a strong marker of the triglyceride-rich lipoprotein (TRL) class for cardiovascular heart disease. The purpose of this research is to demonstrate the efficacy of a novel method that combines an established immunoseparation assay used to measure the RLP class in human serum with ultracentrifugal density gradient separation. These two methods are combined to obtain an RLP density profile.

Method for lipoprotein(a) density profiling by BiEDTA differential density lipoprotein ultracentrifugation.

In this article, we demonstrate the analytical power of linking density gradient ultracentrifugation with affinity separations. Here we address some of the analytical challenges in the study of lipoprotein(a), (Lp(a)). The mean density distribution of Lp(a) was determined by a differential density lipoprotein profile (DDLP).

Metal ion complexes of EDTA as solutes for density gradient ultracentrifugation: influence of metal ions.

In the study reported here, we study the nature of the metal ion complexes of EDTA as solute systems for analysis of lipoproteins by density gradient ultracentrifugation (DGU) by varying both the complexing metal ion and the counterion. Specifically, the sodium and cesium salts of complexes of Bi/EDTA, Pb/EDTA, Cd/EDTA, Fe/EDTA, and Cu/EDTA were chosen for this study. We show that useful gradients can be formed within a few hours beginning with a homogeneous solution.

Novel truncated isoforms of constitutive serum amyloid A detected by MALDI mass spectrometry.

The main focus of the serum amyloid A (SAA) family has been on the acute phase isoforms. However, the constitutive isoform (SAA4) may have a strong effect on the metabolism of human serum lipoproteins. In this study, the SAA4 protein was examined in the high-density lipoprotein fraction of both healthy and diseased individuals.

A large high-density lipoprotein enriched in apolipoprotein C-I: a novel biochemical marker in infants of lower birth weight and younger gestational age.

Context: Low birth weight is associated with increased cardiovascular disease in adulthood, and differences in the molecular weight, composition, and quantity of lipoprotein subclasses are associated with coronary artery disease.

Objective: To determine if there are novel patterns of lipoprotein heterogeneity in low-birth-weight infants.

Design, Setting, And Participants: Prospective study at a US medical center of a representative sample of infants (n = 163; 70 white and 93 black) born at 28 or more weeks of gestational age between January 3, 2000, and September 27, 2000.

Should people be physically active outdoors on smog alert days?

Background: Given the importance of physical activity to well-being, there is a need to encourage people to be physically active year-round. At the same time, many people are vulnerable to adverse health effects from air pollution, especially on smog alert days. This study was undertaken to determine when air pollution levels tend to be lowest so that the public can modify strenuous outdoor activity accordingly.

Metal ion complexes of EDTA: a solute system for density gradient ultracentrifugation analysis of lipoproteins.

In the study reported here, we apply some of the features of coordination chemistry to solve a long-standing problem in the separation and characterization of lipoprotein particles. Lipoproteins are circulating micelle-like particles responsible for lipid transport. They exist in three major classes: very-low-density lipoprotein, low-density lipoprotein, and high-density lipoprotein in well-defined density ranges using the density gradient ultracentrifugation (DGU) method.

Charge density profiling of circulating human low-density lipoprotein particles by capillary zone electrophoresis.

Capillary zone electrophoresis (CZE) has been utilized to profile the low-density (LDL) particles in human blood serum in this study. A 5 mM sodium phosphate buffer, pH 7.40, was chosen as the most suitable CE buffer and an extensive ultrafiltration (UF) procedure was applied to purify the LDL sample.

Lipoprotein heterogeneity at birth: influence of gestational age and race on lipoprotein subclasses and Lp (a) lipoprotein.

Objective: To determine the influence of gestational age, gender, and race, on lipoprotein heterogeneity at birth.

Design: Prospective study of representative sample of infants.

Setting: The Johns Hopkins Hospital.

Analysis of high-density lipoprotein apolipoproteins recovered from specific immobilized pH gradient gel pI domains by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

The proteins associated with the circulating lipoproteins in the blood function not only for mediating lipid metabolism but also for maintaining structural stability of the micellelike structure. Any modifications of these proteins, by mutation or posttranslational modification, could compromise the function of these proteins and contribute to the development of cardiovascular disease. Because of the presence of extensive lipophilic domains, these proteins, when recovered from the lipoprotein particle (apolipoproteins) present an analytical challenge because of low solubility and proclivity toward aggregate formation.