Fuel metabolism in Canada geese: effects of glucagon on glucose kinetics.

During prolonged fasting, birds must rely on glucose mobilization to maintain normoglycemia. Glucagon is known to modulate avian energy metabolism during prolonged fasting, but the metabolic effects of this hormone on long-distance migrant birds have never been investigated. Our goal was to determine whether glucagon regulates the mobilization of the main lipid and carbohydrate fuels in migrant birds.

Randomized controlled trial of motivational interviewing for reducing injection risk behaviours among people who inject drugs.

Aim: We tested the efficacy of a brief intervention based on motivational interviewing (MI) to reduce high-risk injection behaviours over a 6-month period among people who inject drugs (PWID).

Design: A single-site two-group parallel randomized controlled trial comparing MI with a brief educational intervention (EI).

Setting: A study office located in downtown Montréal, Canada, close to the community-based harm reduction programmes where PWID were recruited.

Residential trajectories of street youth-the Montréal Cohort Study.

Little is known about the course of homelessness among youth between the ages of 18 and 25 despite the many characteristics distinguishing them from adolescents and from older street-involved populations. We examined the residential trajectories of homeless young adults in Montréal over a 21-month period and identified determinants of various trajectory profiles. The 365 study participants (79 % men, mean age 21.

Residential trajectory and HIV high-risk behaviors among Montréal street youth--a reciprocal relationship.

Evidence has linked residential instability and engagement in high-risk behaviors. This paper longitudinally examines the relationship between changes in residential stability and changes in HIV risk behaviors among Montréal street youth (SY). Between April 2006 and May 2007, 419 SY (18-25 years old) were recruited in a cohort study.

Drug use patterns in the presence of crack in downtown Montréal.

Introduction And Aims: A study was undertaken to verify reports of an increasing presence of crack in downtown Montréal, and to investigate the influence of crack availability on current drug use patterns among street-based cocaine users.

Design And Methods: The study combined both qualitative and quantitative methods. These included long-term intensive participant observation carried out by an ethnographer familiar with the field and a survey.

Fuel selection in Wistar rats exposed to cold: shivering thermogenesis diverts fatty acids from re-esterification to oxidation.

This study characterizes the effects of shivering thermogenesis on metabolic fuel selection in Wistar rats. Because lipids account for most of the heat produced, we have investigated: (1) whether the rate of appearance of non-esterified fatty acids (R(a) NEFAs) is stimulated by shivering, (2) whether mono-unsaturated (oleate) and saturated fatty acids (palmitate) are affected similarly, and (3) whether the partitioning between fatty acid oxidation and re-esterification is altered by cold exposure. Fuel oxidation was measured by indirect calorimetry and fatty acid mobilization by continuous infusion of 9,10-[(3)H]oleate and 1-[(14)C]palmitate.

In vivo regulation of rainbow trout lipolysis by catecholamines.

Lipolysis provides fatty acids that support key life processes by functioning as membrane components, oxidative fuels and metabolic signals. It is commonly measured as the rate of appearance of glycerol (Ra glycerol). Its in vivo regulation by catecholamines has been thoroughly investigated in mammals, but little information is available for ectotherms.

High resting triacylglycerol turnover of rainbow trout exceeds the energy requirements of endurance swimming.

Fish may use lipoproteins instead of albumin-bound fatty acids to fuel endurance exercise, but lipoprotein kinetics have never been measured in ectotherms. In vivo bolus injections of labeled very-low-density lipoproteins ((3)H-VLDL labeled in vivo from donor fish) and continuous infusions of Intralipid (3H-labeled artificial emulsion) were used to investigate the effects of prolonged exercise (6 h at 1.5 body length/s) and heparin (600 U/kg) on the turnover rate of circulating triacylglycerol (TAG) in rainbow trout.

Treatment of diabetes and atherosclerosis by inhibiting fatty-acid-binding protein aP2.

Adipocyte fatty-acid-binding protein, aP2 (FABP4) is expressed in adipocytes and macrophages, and integrates inflammatory and metabolic responses. Studies in aP2-deficient mice have shown that this lipid chaperone has a significant role in several aspects of metabolic syndrome, including type 2 diabetes and atherosclerosis. Here we demonstrate that an orally active small-molecule inhibitor of aP2 is an effective therapeutic agent against severe atherosclerosis and type 2 diabetes in mouse models.

Coordinated regulation of nutrient and inflammatory responses by STAMP2 is essential for metabolic homeostasis.

Metabolic and inflammatory pathways crosstalk at many levels, and, while required for homeostasis, interaction between these pathways can also lead to metabolic dysregulation under conditions of chronic stress. Thus, we hypothesized that mechanisms might exist to prevent overt inflammatory responses during physiological fluctuations in nutrients or under nutrient-rich conditions, and we identified the six-transmembrane protein STAMP2 as a critical modulator of this integrated response system of inflammation and metabolism in adipocytes. Lack of STAMP2 in adipocytes results in aberrant inflammatory responses to both nutrients and acute inflammatory stimuli.

Lipid mobilization of long-distance migrant birds in vivo: the high lipolytic rate of ruff sandpipers is not stimulated during shivering.

For long migrations, birds must rely on high flux capacities at all steps of lipid metabolism, from the mobilization of adipose reserves to fatty acid oxidation in flight muscle mitochondria. Substrate kinetics and indirect calorimetry were used to investigate key parameters of lipid metabolism in a highly aerobic shorebird: the ruff sandpiper Philomachus pugnax. In this study, we have quantified the effects of cold exposure because such measurements are presently impossible during flight.

Chemical chaperones reduce ER stress and restore glucose homeostasis in a mouse model of type 2 diabetes.

Endoplasmic reticulum (ER) stress is a key link between obesity, insulin resistance, and type 2 diabetes. Here, we provide evidence that this mechanistic link can be exploited for therapeutic purposes with orally active chemical chaperones. 4-Phenyl butyric acid and taurine-conjugated ursodeoxycholic acid alleviated ER stress in cells and whole animals.

Energetics of a long-distance migrant shorebird (Philomachus pugnax) during cold exposure and running.

The metabolic consequences of cold exposure and exercise are not well characterized in birds. Ruff sandpipers Philomachus pugnax are migrant shorebirds traveling between Africa and Siberia for up to 30,000 km annually. Our goal was to quantify the fuel selection pattern of these remarkable athletes during shivering and terrestrial locomotion.