Predictors of mental health service utilization by people using resources for homeless people in Canada.

Objective: This study used Pescosolido's network episode model to examine mental health service utilization among impoverished people accessing resources for the homeless in Canada's universal health care setting.

Methods: The sample consisted of 439 people who met DSM-IV criteria for affective or psychotic disorders who were assessed as part of a larger study of resources for homeless or impoverished people in Montreal and Quebec City. Interviews were organized into the framework of four network episode model concepts: sociodemographic characteristics, illness characteristics, illness history, and social network.

Anticipating ethical aspects of the use of biomarkers in the workplace: a tool for stakeholders.

This research aimed to understand how occupational health stakeholders represented the various ethical concerns raised by the use of biomarkers of exposure, effects and susceptibility to harmful agents. These representations were investigated by seven homogeneous focus group interviews and an Internet discussion forum. The following stakeholders took part in this research: workers, physicians, nurses, researchers, employers, industrial hygienists, trade-union representatives and employees of the Quebec Board of Health and Safety in the Workplace.

Duration of poverty and child health in the Quebec Longitudinal Study of Child Development: longitudinal analysis of a birth cohort.

Objectives: The objective of this study was to examine the relationship between duration of poverty and the health of preschool children in the Quebec Longitudinal Study of Child Development birth cohort.

Methods: Data from the Quebec Longitudinal Study of Child Development for 1950 children who were followed annually up to age 3 years were analyzed. Poverty was defined as having an income below the low-income cutoff from Statistics Canada.

Our social genome?

Apocalyptic views on the natural order, chimeras and genetic engineering should not detract from the fact that medical research, similar to the promotion of health, is a public good. Genomics crosses all species, thereby requiring a global approach that respects human rights and public health priorities. Public trust and public participation in research demand clear stewardship as well as transparent and accountable oversight.

The topographic brain: from neural connectivity to cognition.

A hallmark feature of vertebrate brain organization is ordered topography, wherein sets of neuronal connections preserve the relative organization of cells between two regions. Although topography is often found in projections from peripheral sense organs to the brain, it also seems to participate in the anatomical and functional organization of higher brain centers, for reasons that are poorly understood. We propose that a key function of topography might be to provide computational underpinnings for precise one-to-one correspondences between abstract cognitive representations.

Proton-actuated membrane-destabilizing polyion complex micelles.

The efficiency of nucleic acid-based drugs is usually hampered by the fact that, following their uptake by the cell, these drugs end up in acidic organelles (i.e., endosomes/lysosomes) from which they barely escape.

Rescue of amitriptyline-intoxicated hearts with nanosized vesicles.

Objective: Amitriptyline, one of the most prescribed antidepressants, is reported to claim a large number of human lives due to drug overdose related cardiac arrest. Although amitriptyline poisoning has long been recognized as a frequent and serious fatality in the medical field, few efforts have been made to devise methods for treating its toxicity. To address this issue, phospholipid-based nanosized vesicles (spherulites) were employed to reverse the cardiotoxicity induced by amitriptyline in an isolated heart perfusion model.

Neurotrophins modulate neuron-glia interactions at a vertebrate synapse.

Neurotrophins are important modulators of synaptic function at both developing and mature synapses in the CNS and PNS. At the neuromuscular junction (NMJ), neurotrophins, as well as perisynaptic Schwann cells (PSCs) are critical for the long-term maintenance and stability of the synapse. Considering this correlation and the acute interactions that occur at the synapse between PSCs and the nerve terminal, we wondered if neurotrophins could also be involved in neuron-glia signalling.

Long circulating lipid nanocapsules for drug detoxification.

Uncoated and poly(ethylene glycol) (PEG)-decorated lipid nanocapsules (NC) prepared from medium chain triglycerides were investigated both in vitro and in vivo as parenteral detoxifying colloids for their ability to sequester haloperidol, docetaxel and paclitaxel. In vitro studies showed that the uptake depended on the nature of the drug and the composition of NC core and shell. In the case of haloperidol, maximal affinity was achieved upon incorporation of a complexing fatty acid.

Characterization and in vitro evaluation of spherulites as sequestering vesicles with potential application in drug detoxification.

The aim of the present investigation was to prepare and characterize lecithin spherulites as parenteral drug sequestering agents with potential application in the treatment of drug overdose and chemical poisoning. The spherulites (approximately 200 nm) obtained by controlled hydration and shearing of lipid-alcohol mixtures, revealed unexpected differences in the physical properties of the bilayer when compared to liposomes. Differential scanning calorimetry, 31-phosphorus nuclear magnetic resonance, and pH-sensitive pyranine steady-state fluorescence studies indicated that although spherulites retained the typical bilayer conformation, the arrangement of the phospholipid molecules was perturbed relative to native liposome bilayer.

Integrating psychosocial and behavioral interventions to achieve optimal rehabilitation outcomes.

Introduction: Psychosocial factors are important contributors to work disability associated with musculoskeletal conditions. The primary objectives of this paper were 1) to describe different psychosocial interventions that have been developed to prevent prolonged work disability, and 2) to identify future research directions that might enhance the impact of programs targeting psychosocial risk factors for work disability.

Methods: Selective review of scientific literature on psychosocial and behavioral interventions and work disability.

Exploiting the vitamin B12 pathway to enhance oral drug delivery via polymeric micelles.

Vitamin B12 (VB12)-modified dextran-g-polyethyleneoxide cetyl ether (DEX-g-PEO-C16) was synthesized by linking VB12 residues to a DEX-g-PEO-C16 copolymer via a 2,2'-(ethylenedioxy)bis(ethylamine) spacer. The level of VB12 substitution on the DEX-g-PEO-C16 copolymer reached 1.68% (w/w).

Preparation and in vivo evaluation of PEGylated spherulite formulations.

Spherulites are multilamellar vesicles obtained by shearing a lamellar phase of lipids and surfactants. They consist of concentric bilayers of amphiphiles alternating with layers of aqueous medium in which hydrophilic drugs can be sequestered with high yield. To be useful for drug targeting applications, spherulites should be small and long circulating.

Study of pH-sensitive copolymer/phospholipid complexes using the langmuir balance technique: effect of anchoring sequence and copolymer molecular weight.

The behavior of three copolymers of N-isopropylacrylamide (NIPAM), methacrylic acid (MAA), and hydrophobic moiety was studied at phospholipid monolayer/subphase interfaces. The hydrophobic moieties, N-terminal dioctadecylamine (DODA) and random octadecylacrylate (ODA), were used as anchoring groups. The interactions between a 1,2-distearoyl-sn-glycero-3-phosphatidylcholine (DSPC) monolayer and the copolymers were studied using the Langmuir balance technique.

Cell-type specific GABA synaptic transmission and activity-dependent plasticity in rat hippocampal stratum radiatum interneurons.

Abstract In hippocampal pyramidal cells, the efficacy of synaptic transmission at gamma-aminobutyric acid (GABA)ergic synapses, is modulated by activity. However, whether such plasticity occurs at inhibitory synapses on interneurons remains largely unknown. Using whole-cell voltage-clamp recordings of inhibitory postsynaptic currents (IPSCs) in Sprague-Dawley rat hippocampal slices, we examined whether GABA synapses of stratum radiatum interneurons were affected by stimulation protocols known to alter efficacy at inhibitory synapses of CA1 pyramidal cells.

Enhancement of oral bioavailability of poorly water-soluble drugs by poly(ethylene glycol)-block-poly(alkyl acrylate-co-methacrylic acid) self-assemblies.

The purpose of the present study was to determine whether pH-sensitive polymeric micelles could improve the oral bioavailability of a poorly water-soluble drug. Poly(ethylene glycol)-block-poly(alkyl acrylate-co-methacrylic acid)s were synthesized by atom transfer radical polymerization and the composition of the ionizable polymer block was varied to maximize drug loading and pH-dependent release. Poorly water-soluble model drugs viz.

Stereocomplex block copolymer micelles: core-shell nanostructures with enhanced stability.

Monodisperse stereocomplex block copolymer micelles were obtained through the self-assembly of equimolar mixtures of poly(ethylene glycol)-block-poly(l-lactide) and poly(ethylene glycol)-block-poly(d-lactide) in water. These micelles possessed partially crystallized cores and mean hydrodynamic diameters ranging from 31 to 56 nm, depending on the lactide content. They exhibited kinetic stability and redispersion properties superior to micelles prepared with isotactic or racemic polymers alone.

Dimensions of catastrophic thinking associated with pain experience and disability in patients with neuropathic pain conditions.

The objective of the present study was to examine the relative contributions of different dimensions of catastrophic thinking (i.e. rumination, magnification, helplessness) to the pain experience and disability associated with neuropathic pain.

Effects of the intravitreal administration of dopaminergic ligands on the b-wave amplitude of the rabbit electroretinogram.

In the retina of mammals, dopamine (DA) is generally released by amacrine cells and is known to alter the physiology of most retinal cells. It is well known that DA reduces the amplitude of the b-wave of the electroretinogram (ERG) in rabbit. However, the specific receptor subtypes that mediate this action have not yet been elucidated.

Novel long-circulating lipid nanocapsules.

Purpose: To develop and evaluate novel long-circulating lipid nanocapsules (LN) designed for tumor delivery of lipophilic drugs.

Methods: Nanocapsules were produced by a solvent-free phase inversion process and were coated with polyethylene glycoldistearoylphosphatidylethanolamine conjugate (DSPE-PEG) during preparation or by a post-insertion step. In vivo studies were conducted in rats to assess LN pharmacokinetics and biodistribution.

Report on the use of poly(organophosphazenes) for the design of stimuli-responsive vesicles.

A novel family of amphiphilic temperature- and pH-sensitive poly(organophosphazenes) with varying ratios of ethylene oxide, alkyl chains and free acid units was synthesized by living cationic polymerization. Depending on their composition, these poly(organophosphazenes) exhibited lower critical solution temperatures ranging from 32 to 44 degrees C, which were pH-dependent for copolymers bearing carboxylic acid groups. The alkylated copolymers were then anchored into phospholipid bilayers to obtain stimuli-responsive liposomes that released their content upon a change in temperature or pH.

Internal surface representations approximated by reverse correlation.

We presented two nai ve observers with 20,000 random-dot stereograms. On each trial, the observers had to indicate the presence or absence of a complex 3D pattern (a large '+' sign in relief). However, unbeknownst to them, the stereograms did not contain any signal, but only disparity noise.

In situ-forming pharmaceutical organogels based on the self-assembly of L-alanine derivatives.

Purpose: To characterize novel pharmaceutical organogels based on the self-assembly of L-alanine derivatives in hydrophobic vehicles.

Methods: The gelation properties of N-lauroyl-L-alanine (LA) and N-lauroyl-L-alanine methyl ester (LAM) were investigated in the presence of various solvents. Gel-sol and sol-gel transitions were evaluated by the inverse flow method, and gelation kinetics were determined by turbidimetry.