Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 13 de 13
Filter
1.
J Behav Educ ; 32(2): 261-276, 2023.
Article in English | MEDLINE | ID: mdl-34511863

ABSTRACT

Interteaching is a behavioral teaching method that has been empirically shown to increase student learning outcomes. The present study investigated the effect of combining interteaching with cumulative versus noncumulative exams in two sections of an online asynchronous class. Interteaching was used in both sections of the course. The noncumulative exam section experienced weekly exams with test questions that only covered material learned in that week of class. The cumulative exam section was given weekly exams in which half of the questions were from material learned that current week and the other half were cumulative up to that point in the class. This was followed by a cumulative final exam given to both groups. All exam questions were multiple choice. On average, students in the cumulative exam group scored 4.91% higher on the final exam than students in the noncumulative exam group. Students exposed to weekly cumulative exams also earned more As and Bs on the final compared to the noncumulative exam group. Overall, our experiment provides evidence that interteaching may be further improved when combined with cumulative weekly exams.

3.
Can Commun Dis Rep ; 45(5): 143-148, 2019 May 02.
Article in English | MEDLINE | ID: mdl-31285705

ABSTRACT

Climate change has been linked with the establishment and geographical expansion of zoonotic diseases, an example of which is the well-documented increase in human cases of Lyme disease in Quebec, Canada. As temperatures continue to increase in Quebec, it is anticipated that several zoonotic diseases will be affected. In response to the growing zoonotic issues facing public health authorities, Quebec's Multi-Party Observatory on Zoonoses and Adaptation to Climate Change (Observatoire multipartite québécois sur les zoonoses et l'adaptation aux changements climatiques) (the Observatory) was founded in 2015 as part of the Quebec government's Climate Change Action Plan (Plan d'action 2013-2020 sur les changements climatiques). The Observatory was designed to bring together agencies involved in formulating public policy and experts from the disciplines of human health, animal health and environmental sciences, in a manner similar to the innovative "One World, One Health" approach. The Observatory provides a platform for knowledge sharing and consensus building among representatives of public policy decision makers and scientists. Its main objectives are to anticipate and prioritize potential issues associated with zoonotic diseases in Quebec, in order to support applicable risk management and climate change adaptation. This article describes what the Observatory is, what it does and outlines its plans for the future.

4.
Epidemiol Infect ; 146(9): 1167-1176, 2018 07.
Article in English | MEDLINE | ID: mdl-29716671

ABSTRACT

Jamestown Canyon and snowshoe hare viruses are two emerging human pathogens associated with cases of neuroinvasive disease in North America. This study aimed to identify environmental and individual risk factors for seropositivity to these arboviruses in humans and pet dogs from Québec, Canada, 2012-2014. In humans, areas with moderate densities of white-tailed deer (Odocoileus virginianus) were associated with higher odds of seropositivity compared with areas with low densities of white-tailed deer (OR 2.50, P = 0.009) and odds of seropositivity were higher in males than in females (OR 2.03, P = 0.016). Among humans reporting more than 10 mosquito bites weekly, the odds of being seropositive were 4.44 times higher (P = 0.004) for people living in hardwood forested areas. Exposure to areas with coniferous forests was identified as the main environmental risk factor for seroconversion in dogs (OR 2.39, P = 0.04). These findings may help target further public health research, diagnostic and surveillance efforts in Canada.


Subject(s)
Dog Diseases/etiology , Encephalitis, California/etiology , Pets , Animals , Cross-Sectional Studies , Dog Diseases/epidemiology , Dogs , Encephalitis, California/diagnosis , Encephalitis, California/epidemiology , Encephalitis, California/veterinary , Female , Humans , Logistic Models , Male , Multivariate Analysis , Odds Ratio , Public Health Surveillance , Quebec , Risk Factors , Seroepidemiologic Studies
5.
Epidemiol Infect ; 145(14): 2940-2948, 2017 10.
Article in English | MEDLINE | ID: mdl-28956525

ABSTRACT

Periodic outbreaks of West Nile virus (WNV), Eastern equine encephalitis virus (EEEV) and to a lesser extent, California serogroup viruses (CSGV), have been reported in parts of Canada in the last decade. This study was designed to provide a broad assessment of arboviral activity in Quebec, Canada, by conducting serological surveys for these arboviruses in 196 horses, 1442 dogs and 485 humans. Sera were screened by a competitive enzyme linked immunosorbent assay and positive samples confirmed by plaque reduction neutralisation tests. The percentage of seropositive samples was 83·7%, 16·5%, 7·1% in horses, 18·8%, 0·6%, 0% in humans, 11·7%, 3·1%, 0% in adult dogs and 2·9%, 0·3%, 0% in juvenile dogs for CSGV, WNV and EEEV, respectively. Serological results in horses and dogs appeared to provide a meaningful assessment of risk to public health posed by multiple arboviruses.


Subject(s)
Arbovirus Infections/epidemiology , Arbovirus Infections/veterinary , Communicable Diseases, Emerging/epidemiology , Adult , Animals , Arbovirus Infections/virology , Arboviruses/physiology , Communicable Diseases, Emerging/virology , Dog Diseases/blood , Dog Diseases/epidemiology , Dog Diseases/virology , Dogs , Encephalitis Virus, California/physiology , Encephalitis Virus, Eastern Equine/physiology , Encephalitis, California/epidemiology , Encephalitis, California/virology , Encephalomyelitis, Equine/epidemiology , Encephalomyelitis, Equine/virology , Female , Horse Diseases/blood , Horse Diseases/epidemiology , Horse Diseases/virology , Horses , Humans , Male , Middle Aged , Public Health , Quebec/epidemiology , West Nile Fever/epidemiology , West Nile Fever/virology , West Nile virus/physiology
6.
Epidemiol Infect ; 145(13): 2797-2807, 2017 10.
Article in English | MEDLINE | ID: mdl-28835296

ABSTRACT

The identification of specific environments sustaining emerging arbovirus amplification and transmission to humans is a key component of public health intervention planning. This study aimed at identifying environmental factors associated with West Nile virus (WNV) infections in southern Quebec, Canada, by modelling and jointly interpreting aggregated clinical data in humans and serological data in pet dogs. Environmental risk factors were estimated in humans by negative binomial regression based on a dataset of 191 human WNV clinical cases reported in the study area between 2011 and 2014. Risk factors for infection in dogs were evaluated by logistic and negative binomial models based on a dataset including WNV serological results from 1442 dogs sampled from the same geographical area in 2013. Forested lands were identified as low-risk environments in humans. Agricultural lands represented higher risk environments for dogs. Environments identified as impacting risk in the current study were somewhat different from those identified in other studies conducted in north-eastern USA, which reported higher risk in suburban environments. In the context of the current study, combining human and animal data allowed a more comprehensive and possibly a more accurate view of environmental WNV risk factors to be obtained than by studying aggregated human data alone.


Subject(s)
Dog Diseases/epidemiology , West Nile Fever/epidemiology , West Nile Fever/veterinary , West Nile virus/physiology , Animals , Cross-Sectional Studies , Dog Diseases/blood , Dog Diseases/virology , Dogs , Environment , Female , Humans , Incidence , Male , Models, Theoretical , Prevalence , Public Health , Quebec/epidemiology , Risk Factors , Seroepidemiologic Studies , West Nile Fever/blood , West Nile Fever/virology
7.
Epidemiol Infect ; 145(4): 667-677, 2017 03.
Article in English | MEDLINE | ID: mdl-27903326

ABSTRACT

Eastern equine encephalitis (EEE) is a rare but severe emerging vector-borne disease affecting human and animal populations in the northeastern United States where it is endemic. Key knowledge gaps remain about the epidemiology of EEE virus (EEEV) in areas where its emergence has more recently been reported. In Eastern Canada, viral activity has been recorded in mosquitoes and horses throughout the 2000s but cases of EEEV in humans have not been reported so far. This study was designed to provide an assessment of possible EEEV human exposure by modelling environmental risk factors for EEEV in horses, identifying high-risk environments and mapping risk in the province of Quebec, Canada. According to logistic models, being located near wooded swamps was a risk factor for seropositivity or disease in horses [odds ratio (OR) 4·15, 95% confidence interval (CI) 1·16-14·8) whereas being located on agricultural lands was identified as protective (OR 0·75, 95% CI 0·62-0·92). A better understanding of the environmental risk of exposure to EEEV in Canada provides veterinary and public health officials with enhanced means to more effectively monitor the emergence of this public health risk and design targeted surveillance and preventive measures.


Subject(s)
Antibodies, Viral/blood , Encephalitis Virus, Eastern Equine/immunology , Encephalomyelitis, Eastern Equine/veterinary , Environmental Exposure , Horse Diseases/epidemiology , Horses , Animals , Encephalomyelitis, Eastern Equine/epidemiology , Female , Humans , Male , Quebec/epidemiology , Risk Assessment
8.
Vitam Horm ; 101: 17-58, 2016.
Article in English | MEDLINE | ID: mdl-27125737

ABSTRACT

Scientific evidence is quickly growing that establishes FGF21 as a cytokine that signals both locally and systemically to induce metabolic effects. The focus of this chapter is the receptor/co-receptor signaling complex formed by endocrine FGF21. We provide an introduction to the major components of the complex including the Klotho family of co-receptors, fibroblast growth factor receptors (FGFRs), and the fibroblast growth factor ligands, placing each in the context of its own family members while emphasizing structural features that drive interaction. We subsequently focus specifically on FGF21 signaling through FGFR1c and KLB, describing what is known about each protein's structure and how this drives protein interaction and formation of the signaling complex at the plasma membrane. We subsequently explore the stoichiometry of FGFR1c and KLB at the plasma membrane before and after the addition of FGF21 ligand, comparing how unique features of the interaction could potentially affect signaling intensity. Finally, we discuss how formation of the signaling complex is potentially regulated by other regulatory interactions, including galectins, the extracellular matrix, and co-expression of FGFR5.


Subject(s)
Fibroblast Growth Factors , Membrane Proteins , Receptor, Fibroblast Growth Factor, Type 1 , Receptors, Fibroblast Growth Factor , Signal Transduction , Amino Acid Sequence , Animals , Binding Sites , Fibroblast Growth Factors/metabolism , Gene Expression , Genetic Variation , Humans , Klotho Proteins , Membrane Proteins/chemistry , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mice , Mice, Knockout , Protein Multimerization , Receptor, Fibroblast Growth Factor, Type 1/chemistry , Receptor, Fibroblast Growth Factor, Type 1/metabolism , Receptors, Fibroblast Growth Factor/chemistry , Receptors, Fibroblast Growth Factor/metabolism
9.
Diabetologia ; 49(10): 2368-78, 2006 Oct.
Article in English | MEDLINE | ID: mdl-16924481

ABSTRACT

AIMS/HYPOTHESIS: ATP-sensitive K(+) (K(ATP)) channels couple glucose metabolism to insulin secretion in pancreatic beta cells. In humans, loss-of-function mutations of beta cell K(ATP) subunits (SUR1, encoded by the gene ABCC8, or Kir6.2, encoded by the gene KCNJ11) cause congenital hyperinsulinaemia. Mice with dominant-negative reduction of beta cell K(ATP) (Kir6.2[AAA]) exhibit hyperinsulinism, whereas mice with zero K(ATP) (Kir6.2(-/-)) show transient hyperinsulinaemia as neonates, but are glucose-intolerant as adults. Thus, we propose that partial loss of beta cell K(ATP) in vivo causes insulin hypersecretion, but complete absence may cause insulin secretory failure. MATERIALS AND METHODS: Heterozygous Kir6.2(+/-) and SUR1(+/-) animals were generated by backcrossing from knockout animals. Glucose tolerance in intact animals was determined following i.p. loading. Glucose-stimulated insulin secretion (GSIS), islet K(ATP) conductance and glucose dependence of intracellular Ca(2+) were assessed in isolated islets. RESULTS: In both of the mechanistically distinct models of reduced K(ATP) (Kir6.2(+/-) and SUR1(+/-)), K(ATP) density is reduced by approximately 60%. While both Kir6.2(-/-) and SUR1(-/-) mice are glucose-intolerant and have reduced glucose-stimulated insulin secretion, heterozygous Kir6.2(+/-) and SUR1(+/-) mice show enhanced glucose tolerance and increased GSIS, paralleled by a left-shift in glucose dependence of intracellular Ca(2+) oscillations. CONCLUSIONS/INTERPRETATION: The results confirm that incomplete loss of beta cell K(ATP) in vivo underlies a hyperinsulinaemic phenotype, whereas complete loss of K(ATP) underlies eventual secretory failure.


Subject(s)
ATP-Binding Cassette Transporters/genetics , Hyperinsulinism/genetics , Loss of Heterozygosity , Multidrug Resistance-Associated Proteins/deficiency , Multidrug Resistance-Associated Proteins/genetics , Potassium Channels, Inwardly Rectifying/deficiency , Potassium Channels, Inwardly Rectifying/genetics , Animals , Blood Glucose/metabolism , Insulin/genetics , Insulin/metabolism , Insulin Secretion , Kinetics , Mice , Mice, Knockout , Potassium Channels/genetics , Receptors, Drug , Sulfonylurea Receptors
10.
Eur J Biochem ; 268(10): 2924-30, 2001 May.
Article in English | MEDLINE | ID: mdl-11358509

ABSTRACT

The mechanism of Sendai virus membrane fusion to cultured cell membranes was studied. Viral lipids were labeled with the lipophilic dye, 4-(4-(dihexadecylamino)styryl-N-methylquinolinium iodine) (DiQ), and viral proteins were labeled using fluorescein isothiocyanate (FITC). The redistribution of these probes from the virus to cultured cells was followed using the technique of image correlation spectroscopy. This technique assayed the intensity change and the redistribution of these probes as fusion progressed from a more to less aggregated state. The lipid probe DiQ dispersed into the membrane of the target membrane at both 22 and 37 degrees C, while the FITC-labeled proteins dispersed only at 37 degrees C. Simultaneous labeling of virus with both of these probes showed that at 37 degrees C their redistribution proceeded at different rates. These data were consistent with the formation of a hemifusion intermediate during the fusion process.


Subject(s)
Cell Membrane/chemistry , Cell Membrane/metabolism , Membrane Fusion , Respirovirus/metabolism , Spectrometry, Fluorescence/methods , Animals , Cell Line , Circular Dichroism , Fluorescein-5-isothiocyanate/pharmacology , Fluorescent Dyes/pharmacology , Haplorhini , Microscopy, Confocal/methods , Quinolinium Compounds/pharmacology , Respirovirus/chemistry , Temperature , Time Factors
11.
Biosci Rep ; 20(3): 139-55, 2000 Jun.
Article in English | MEDLINE | ID: mdl-11095114

ABSTRACT

Receptor aggregation is believed to be an important step in the attachment of membrane enveloped virus' to target cell membranes. A likely receptor for Sendai virus is the ganglioside GD1a. In this work we have studied the membrane diffusion of the fluorescent ganglioside NBD-GD1a on the surface of CV-1 cells with standard photobleaching techniques. Using confocal laser scanning microscopy (CLSM) and Image Correlation Spectroscopy (ICS) NBD-GD1a is shown to exist in at least two populations: dispersed and aggregated. By quantifying the distribution of NBD-GD1a pre- and post-incubation with Sendai virus it is shown that the virus induces a dose-dependent clustering of NBD-GD1a. Image cross-correlation spectroscopy (ICCS) is used to further quantitatively characterize this clustering by demonstrating that it occurs due to binding of virus to the dispersed population of NBD-GD1a.


Subject(s)
Gangliosides/metabolism , Receptors, Virus/metabolism , Respirovirus/metabolism , Animals , Cell Line , Cell Membrane/drug effects , Cell Membrane/metabolism , Diffusion/drug effects , Fibroblasts/drug effects , Fibroblasts/metabolism , Fibroblasts/virology , Fluorescent Dyes/metabolism , Haplorhini , Microscopy, Confocal , Receptor Aggregation/drug effects , Sodium Azide/pharmacology , Spectrum Analysis , Temperature
12.
Faraday Discuss ; (111): 289-305; discussion 331-43, 1998.
Article in English | MEDLINE | ID: mdl-10822615

ABSTRACT

Communication between cells invariably involves interactions of a signalling molecule with a receptor at the surface of the cell. Typically, the receptor is imbedded in the membrane and it is hypothesized that the binding of the signalling molecule causes a change in the state of aggregation of the receptor which, in turn, initiates a biochemical signal within the cell. Subsequently, many of the occupied receptors bind to membrane-associated structures, called coated pits, which invaginate and pinch off to form coated vesicles, thereby removing the receptors from the cell surface. The state of aggregation of membrane receptors is obviously in constant flux. Any useful approach to measuring the state of aggregation must, therefore, allow for dynamic measurements in living cells. It is possible to use fluorescently labelled signalling molecules or antibodies directed at the receptor of interest to visualize the receptor on the cell surface with a fluorescence microscope. By employing a laser confocal microscope, high resolution images can be produced in which the fluorescence intensity is quantitatively imaged as a function of position across the surface of the cell. Calculations of autocorrelation functions of these images provide direct and accurate measures of the density of fluorescent particles on the surface. Combined with the average intensity in the image, which reflects the total average number of molecules, it is possible to estimate the degree of aggregation of the receptor molecules. We refer to this analysis as image correlation spectroscopy (ICS). We show how ICS can be used to measure the density of several receptors on a variety of cells and how it can be used to measure the density of coated pits and the number of molecules per coated pit. We also show how the technique can be used to monitor fusion of virus particles to cell membranes. Further, we illustrate that, by calculating cross-correlation functions between pairs of images, we can extend the analysis to measurements of the distributions as a function of time, on the second timescale, as well as to measurements of the movement of the receptor aggregates on the surface. Finally, we illustrate that, by this approach, we can measure the extent of interaction between two different receptors as a function of time. This represents the most quantitative measurement of the extent of co-localization of receptors available and is independent of the spatial resolution of the confocal microscope. The theory of ICS and image cross-correlation spectroscopy (ICCS), focussing on the interpretation of the data in terms of the biological phenomenon being probed, is discussed.


Subject(s)
Cell Membrane/chemistry , Membrane Proteins/chemistry , Models, Theoretical , Animals , Cells, Cultured , Protein Binding , Spectrum Analysis , Surface Properties
13.
Birth Defects Orig Artic Ser ; 13(3A): 53-9, 1977.
Article in English | MEDLINE | ID: mdl-884243

ABSTRACT

One thousand consecutive new registrations at the B.C. Health Surveillance Registry were coded by means of ICD (8th Edition), Cardiff Classification, and SNOMED systems. The Cardiff system uses the basic ICD number with important fifth and sixth digit modifiers, which improve discrimination. In certain conditions, however, the basic three-digit number differs from that in ICD and hence comparability is not always possible. The SNOMED system has six subcategories, followed by a five-digit code. These subcategories deal with Function, Disease, Topography, Etiology, Morphology, and Procedure. For our particular needs, the SNOMED system was not entirely satisfactory as it has not expanded sufficiently for many of the malformation syndromes. For hospital use, though, the SNOMED system may have numerous advantages over other existing systems.


Subject(s)
Congenital Abnormalities/classification , Genetic Diseases, Inborn/classification , Female , Humans , Male , Methods , Syndrome , Terminology as Topic
SELECTION OF CITATIONS
SEARCH DETAIL
...