13 results on '"Louie AM"'
Search Results
2. Blockade of receptor-activated Gi signaling in osteoblasts in vivo leads to site-specific increases in cortical and cancellous bone formation
- Author
-
Millard, SM, Louie, AM, Wattanachanya, L, Wronski, TJ, Conklin, BR, and Nissenson, RA
- Abstract
Osteoblasts play a critical role in the maintenance of bone mass through bone formation and regulation of bone resorption. Targeted expression of a constitutively active engineered Gi-coupled G protein-coupled receptor (GPCR) to osteoblasts in vivo leads to severe osteopenia. However, little is known about the role of endogenous receptor-mediated Gi signaling in regulating osteoblast function. In this study, we investigated the skeletal effects of blocking Gi-coupled signaling in osteoblasts in vivo. This was accomplished by transgenic expression of the catalytic subunit of pertussis toxin (PTX) under control of the collagen Iα 2.3-kb promoter. These mice, designated Col1(2.3)+/PTX+, showed increased cortical thickness at the femoral midshaft at 12 weeks of age. This correlated with increased periosteal bone formation associated with expanded mineralizing surface observed in 8-week-old mice of both genders. The cancellous bone phenotype of the Col1(2.3)+/PTX+ mice was sexually dimorphic, with increases in fractional bone volume at the distal femur seen only in females. Similarly, while cancellous bone-formation rates were unchanged in males, they could not be quantified for female Col1(2.3)+/ PTX+ mice owing to the disorganized nature of the labeling pattern, which was consistent with rapid formation of woven bone. Alterations in osteoclast activity did not appear to participate in the phenotype. These data demonstrate that Gi-coupled signaling by GPCRs endogenous to osteoblasts plays a complex role in the regulation of bone formation in a manner that is dependent on both gender and the anatomic site within bone. Copyright © 2011 American Society for Bone and Mineral Research.
- Published
- 2011
3. Psychosocial and other working conditions in relation to body mass index in a representative sample of Australian workers
- Author
-
Ostry, AS, Radi, S, Louie, AM, LaMontagne, AD, Ostry, AS, Radi, S, Louie, AM, and LaMontagne, AD
- Abstract
BACKGROUND: The aim of the study was to examine the relationship between psychosocial and other working conditions and body-mass index (BMI) in a working population. This study contributes to the approximately dozen investigations of job stress, which have demonstrated mixed positive and negative results in relation to obesity, overweight and BMI. METHODS: A cross-sectional population-based survey was conducted among working Australians in the state of Victoria. Participants were contacted by telephone from a random sample of phone book listings. Information on body mass index was self-reported as were psychosocial work conditions assessed using the demand/control and effort/reward imbalance models. Other working conditions measured included working hours, shift work, and physical demand. Separate linear regression analyses were undertaken for males and females, with adjustment for potential confounders. RESULTS: A total of 1101 interviews (526 men and 575 women) were completed. Multivariate models (adjusted for socio-demographics) demonstrated no associations between job strain, as measured using the demand/control model, or ERI using the effort/reward imbalance model (after further adjustment for over commitment) and BMI among men and women. Multivariate models demonstrated a negative association between low reward and BMI among women. Among men, multivariate models demonstrated positive associations between high effort, high psychological demand, long working hours and BMI and a negative association between high physical demand and BMI. After controlling for the effort/reward imbalance or the demand/control model, the association between physical demand and working longer hours and BMI remained. CONCLUSION: Among men and women the were differing patterns of both exposures to psychosocial working conditions and associations with BMI. Among men, working long hours was positively associated with higher BMI and this association was partly independent of job stress. A
- Published
- 2006
4. A case control study of differences in non-work injury and accidents among sawmill workers in rural compared to urban British Columbia, Canada
- Author
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Maggi Stefania, Hershler Ruth, Chen Lisa, Louie Amber, Hertzman Clyde, and Ostry Aleck
- Subjects
Public aspects of medicine ,RA1-1270 - Abstract
Abstract Background Using a cohort of British Columbian male sawmill workers, we conducted a nested case-control study of the impact of rural compared to urban residence as well as rural/urban migration patterns in relation to hospitalization for non-work injury. We postulate that for many types of non-work injuries, rates will be higher in rural communities than in urban ones and that rates will also be higher for workers who migrate from urban to rural communities. Methods Using conditional logistic regression, univariate models were first run with each of five non-work injury outcomes. These outcomes were hospitalizations due to assault, accidental poisoning, medical mis-adventure, motor vehicle trauma, and other non-work injuries. In multivariate models marital status, ethnicity, duration of employment, and occupation were forced into the model and associations with urban, compared to rural, residence and various urban/migration patterns were tested. Results Urban or rural residence and migration status from urban to other communities, and across rural communities, were not associated with hospitalization for medical misadventure, assault, or accidental poisoning. The likelihood of a rural resident being hospitalized for motor vehicle trauma is higher than for an urban resident. The likelihood that a rural resident is hospitalized for "other" non-work injury is higher than for an urban resident. Conclusion In a relatively homogenous group of workers, and using a rigorous study design, we have demonstrated that the odds of other non-work injury are much higher for workers resident in and migrating to rural regions of Canada than they are for workers resident in or migrating to urban places.
- Published
- 2009
5. Psychosocial and other working conditions in relation to body mass index in a representative sample of Australian workers
- Author
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Louie Amber M, Radi Samia, Ostry Aleck S, and LaMontagne Anthony D
- Subjects
Public aspects of medicine ,RA1-1270 - Abstract
Abstract Background The aim of the study was to examine the relationship between psychosocial and other working conditions and body-mass index (BMI) in a working population. This study contributes to the approximately dozen investigations of job stress, which have demonstrated mixed positive and negative results in relation to obesity, overweight and BMI. Methods A cross-sectional population-based survey was conducted among working Australians in the state of Victoria. Participants were contacted by telephone from a random sample of phone book listings. Information on body mass index was self-reported as were psychosocial work conditions assessed using the demand/control and effort/reward imbalance models. Other working conditions measured included working hours, shift work, and physical demand. Separate linear regression analyses were undertaken for males and females, with adjustment for potential confounders. Results A total of 1101 interviews (526 men and 575 women) were completed. Multivariate models (adjusted for socio-demographics) demonstrated no associations between job strain, as measured using the demand/control model, or ERI using the effort/reward imbalance model (after further adjustment for over commitment) and BMI among men and women. Multivariate models demonstrated a negative association between low reward and BMI among women. Among men, multivariate models demonstrated positive associations between high effort, high psychological demand, long working hours and BMI and a negative association between high physical demand and BMI. After controlling for the effort/reward imbalance or the demand/control model, the association between physical demand and working longer hours and BMI remained. Conclusion Among men and women the were differing patterns of both exposures to psychosocial working conditions and associations with BMI. Among men, working long hours was positively associated with higher BMI and this association was partly independent of job stress. Among men physical demand was negatively associated with BMI and this association was independent of job stress.
- Published
- 2006
- Full Text
- View/download PDF
6. Dental caries disparities in early childhood: A study of kindergarten children in British Columbia.
- Author
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Poon BT, Holley PC, Louie AM, and Springinotic CM
- Subjects
- British Columbia epidemiology, Child, Child, Preschool, Dental Health Surveys, Humans, Retrospective Studies, Dental Caries epidemiology, Health Status Disparities, Residence Characteristics statistics & numerical data, Social Class
- Abstract
Objective: The objective of this paper was to describe results of a public health-administered, provincial dental survey of children aged 4-6 years old in British Columbia, and assess the changes in rates of dental caries geographically and by neighbourhood socio-economic status between baseline (2006/07) and follow-up data collection (2009/10)., Method: The study design involved two retrospective cohorts of kindergarten children who received a public health-administered dental assessment in the years 2006/07 and 2009/10. Neighbourhood socio-economic status was measured by an index created from Canadian Census and Tax Filer data sets. The dental outcomes included previous decay experience, untreated visible decay, and urgent treatment needs., Results: The analysis comprised dental outcomes for 35,602 kindergarten children in 2006/07 and 35,215 children in 2009/10. There was a modest decrease in dental decay rates between surveys, with rates of decay experience - previous and untreated - of 38.9% and 36.7% respectively. However, there were disparities, with almost 50% of children with dental decay in the most socio-economically disadvantaged neighbourhoods, and approximately 30% with dental decay in the least disadvantaged areas., Conclusion: The kindergarten dental survey had extensive coverage, was at the population level, and enabled analysis of change in early childhood dental decay rates over time and by geography. Although overall rates improved, dental health inequalities persisted in both survey years at both regional and neighbourhood levels.
- Published
- 2015
- Full Text
- View/download PDF
7. Stakeholder perceptions of job stress in an industrialized country: implications for policy and practice.
- Author
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Page KM, LaMontagne AD, Louie AM, Ostry AS, Shaw A, and Shoveller JA
- Subjects
- Female, Humans, Male, Policy Making, Qualitative Research, Sex Factors, Stereotyping, Victoria, Health Knowledge, Attitudes, Practice, Occupational Diseases psychology, Stress, Psychological psychology, Workplace psychology
- Abstract
We used a secondary, qualitative analysis of stakeholder perceptions of work stress in Australia to characterize the context for policy and practice intervention. Themes included: Individual versus contextual descriptions of stress; perceived 'gender' differences in manifesting and reporting of stress; the work/home interface; and perceived sectoral and occupational differences in compensation claim rates. We found that people often still perceive stress as an individual rather than organizational problem and view work stress as a stereotypically feminine weakness that affects only certain people. Organizations downplay and overlook risks, increasing worker reluctance to report stressors, creating barriers to job stress interventions. Our study may be relevant to other industrial countries where researchers currently study job stress interventions to improve their effectiveness. Comprehensive approaches can increase knowledge and decrease stigma about job stress and mental illness, and target both work- and non-work-related influences on mental health.
- Published
- 2013
- Full Text
- View/download PDF
8. Psychosocial and other working conditions: variation by employment arrangement in a sample of working Australians.
- Author
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LaMontagne AD, Smith PM, Louie AM, Quinlan M, Ostry AS, and Shoveller J
- Subjects
- Adaptation, Psychological, Adult, Age Factors, Australia, Confidence Intervals, Cross-Sectional Studies, Female, Health Promotion, Health Surveys, Humans, Male, Middle Aged, Multivariate Analysis, Odds Ratio, Psychometrics, Sex Factors, Time Factors, Employment psychology, Environment, Occupational Exposure adverse effects, Occupational Health, Stress, Psychological psychology
- Abstract
Background: The evidence linking precarious employment with poor health is mixed. Self-reported occupational exposures in a population-based Australian sample were assessed to investigate the potential for differential exposure to psychosocial and other occupational hazards to contribute to such a relationship, hypothesizing that exposures are worse under more precarious employment arrangements (EA)., Methods: Various psychoscial and other working conditions were modeled in relation to eight empirically derived EA categories with Permanent Full-Time (PFT) as the reference category (N = 925), controlling for sex, age, and occupational skill level., Results: More precarious EA were associated with higher odds of adverse exposures. Casual Full-Time workers had the worst exposure profile, showing the lowest job control, as well as the highest odds of multiple job holding, shift work, and exposure to four or more additional occupational hazards. Fixed-Term Contract workers stood out as the most likely to report job insecurity. Self-employed workers showed the highest job control, but also the highest odds of long working hours., Conclusions: Psychosocial and other working conditions were generally worse under more precarious EA, but patterns of adverse occupational exposures differ between groups of precariously employed workers., (Copyright © 2011 Wiley Periodicals, Inc.)
- Published
- 2012
- Full Text
- View/download PDF
9. Blockade of receptor-activated G(i) signaling in osteoblasts in vivo leads to site-specific increases in cortical and cancellous bone formation.
- Author
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Millard SM, Louie AM, Wattanachanya L, Wronski TJ, Conklin BR, and Nissenson RA
- Subjects
- Age Factors, Animals, Body Weight drug effects, Body Weight physiology, Calcification, Physiologic physiology, Collagen Type I blood, Collagen Type I genetics, Cyclins genetics, Doxycycline pharmacology, Female, Femur anatomy & histology, Femur cytology, Femur growth & development, Femur metabolism, Fibrillar Collagens metabolism, Gene Expression drug effects, Gene Expression genetics, Male, Mice, Mice, Inbred Strains, Mice, Transgenic, Osteoblasts cytology, Osteoclasts cytology, Osteoclasts metabolism, Osteoprotegerin genetics, Peptide Fragments blood, Peptides blood, Pertussis Toxin genetics, Procollagen blood, Promoter Regions, Genetic genetics, RANK Ligand genetics, Receptors, Calcitonin genetics, Receptors, G-Protein-Coupled antagonists & inhibitors, Receptors, G-Protein-Coupled metabolism, Sex Characteristics, X-Ray Microtomography, GTP-Binding Protein alpha Subunits, Gi-Go antagonists & inhibitors, GTP-Binding Protein alpha Subunits, Gi-Go metabolism, Osteoblasts metabolism, Osteogenesis physiology, Signal Transduction physiology
- Abstract
Osteoblasts play a critical role in the maintenance of bone mass through bone formation and regulation of bone resorption. Targeted expression of a constitutively active engineered G(i)-coupled G protein-coupled receptor (GPCR) to osteoblasts in vivo leads to severe osteopenia. However, little is known about the role of endogenous receptor-mediated G(i) signaling in regulating osteoblast function. In this study, we investigated the skeletal effects of blocking G(i)-coupled signaling in osteoblasts in vivo. This was accomplished by transgenic expression of the catalytic subunit of pertussis toxin (PTX) under control of the collagen Iα 2.3-kb promoter. These mice, designated Col1(2.3)(+)/PTX(+), showed increased cortical thickness at the femoral midshaft at 12 weeks of age. This correlated with increased periosteal bone formation associated with expanded mineralizing surface observed in 8-week-old mice of both genders. The cancellous bone phenotype of the Col1(2.3)(+)/PTX(+) mice was sexually dimorphic, with increases in fractional bone volume at the distal femur seen only in females. Similarly, while cancellous bone-formation rates were unchanged in males, they could not be quantified for female Col1(2.3)(+)/PTX(+) mice owing to the disorganized nature of the labeling pattern, which was consistent with rapid formation of woven bone. Alterations in osteoclast activity did not appear to participate in the phenotype. These data demonstrate that G(i)-coupled signaling by GPCRs endogenous to osteoblasts plays a complex role in the regulation of bone formation in a manner that is dependent on both gender and the anatomic site within bone., (Copyright © 2011 American Society for Bone and Mineral Research.)
- Published
- 2011
- Full Text
- View/download PDF
10. Unwanted sexual advances at work: variations by employment arrangement in a sample of working Australians.
- Author
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Lamontagne AD, Smith PM, Louie AM, Quinlan M, Shoveller J, and Ostry AS
- Subjects
- Adolescent, Adult, Australia, Cross-Sectional Studies, Employment psychology, Female, Humans, Logistic Models, Male, Middle Aged, Occupations classification, Sex Distribution, Sexual Harassment psychology, Young Adult, Employment statistics & numerical data, Occupations statistics & numerical data, Sexual Harassment statistics & numerical data, Workplace psychology
- Abstract
Objective: We tested the hypothesis that the risk of experiencing unwanted sexual advances at work (UWSA) is greater for precariously-employed workers in comparison to those in permanent or continuing employment., Methods: A cross-sectional population-based telephone survey was conducted in Victoria (66% response rate, N=1,101). Employment arrangements were analysed using eight differentiated categories, as well as a four-category collapsed measure to address small cell sizes. Self-report of unwanted sexual advances at work was modelled using multiple logistic regression in relation to employment arrangement, controlling for gender, age, and occupational skill level., Results: Forty-seven respondents reported UWSA in our sample (4.3%), mainly among women (37 of 47). Risk of UWSA was higher for younger respondents, but did not vary significantly by occupational skill level or education. In comparison to Permanent Full-Time, three employment arrangements were strongly associated with UWSA after adjustment for age, gender, and occupational skill level: Casual Full-Time OR = 7.2 (95% Confidence Interval 1.7-30.2); Fixed-Term Contract OR = 11.4 (95% CI 3.4-38.8); and Own-Account Self-Employed OR = 3.8 (95% CI 1.2-11.7). In analyses of females only, the magnitude of these associations was further increased., Conclusions: Respondents employed in precarious arrangements were more likely to report being exposed to UWSA, even after adjustment for age and gender., Implications: Greater protections from UWSA are likely needed for precariously employed workers.
- Published
- 2009
- Full Text
- View/download PDF
11. A systematic review of the job-stress intervention evaluation literature, 1990-2005.
- Author
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Lamontagne AD, Keegel T, Louie AM, Ostry A, and Landsbergis PA
- Subjects
- Humans, Occupational Health Services, Research Design, Occupational Health, Stress, Psychological, Workplace
- Abstract
Ninety reports of systematic evaluations of job-stress interventions were rated in terms of the degree of systems approach used. A high rating was defined as both organizationally and individually focused, versus moderate (organizational only), and low (individual only). Studies using high-rated approaches represent a growing proportion of the job-stress intervention evaluation literature. Individual-focused, low-rated approaches are effective at the individual level, favorably affecting individual-level outcomes, but tend not to have favorable impacts at the organizational level. Organizationally-focused high- and moderate-rated approaches are beneficial at both individual and organizational levels. Further measures are needed to foster the dissemination and implementation of systems approaches to examining interventions for job stress.
- Published
- 2007
- Full Text
- View/download PDF
12. The impact of psychosocial work conditions on attempted and completed suicide among western Canadian sawmill workers.
- Author
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Ostry A, Maggi S, Tansey J, Dunn J, Hershler R, Chen L, Louie AM, and Hertzman C
- Subjects
- British Columbia epidemiology, British Columbia ethnology, Cohort Studies, Forestry, Humans, Male, Occupational Exposure adverse effects, Social Support, Socioeconomic Factors, Suicide ethnology, Suicide statistics & numerical data, Suicide, Attempted ethnology, Suicide, Attempted statistics & numerical data, Surveys and Questionnaires, Workplace, Suicide psychology, Suicide, Attempted psychology
- Abstract
Background: Using a large cohort of western Canadian sawmill workers (n = 28,794), the association between psychosocial work conditions and attempted and completed suicide was investigated., Methods: Records of attempted and completed suicide were accessed through a provincial hospital discharge registry to identify cases that were then matched using a nested case control method. Psychosocial work conditions were estimated by expert raters using the demand-control model. Univariate and multivariate conditional logistic regression was used to estimate the association between work conditions and suicide., Results: In multivariate models, controlling for sociodemographic (marital status, ethnicity) and occupational confounders (job mobility and duration), low psychological demand was associated with increased odds for completed suicide, and low social support was associated with increased odds for attempted suicides., Conclusions: This study indicates that workers with poor psychosocial working conditions may be at increased risk of both attempted and completed suicide.
- Published
- 2007
- Full Text
- View/download PDF
13. Psychosocial and other working conditions in relation to body mass index in a representative sample of Australian workers.
- Author
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Ostry AS, Radi S, Louie AM, and LaMontagne AD
- Subjects
- Adolescent, Adult, Cross-Sectional Studies, Female, Humans, Linear Models, Male, Middle Aged, Models, Psychological, Multivariate Analysis, Socioeconomic Factors, Stress, Psychological epidemiology, Surveys and Questionnaires, Victoria epidemiology, Body Mass Index, Occupational Exposure adverse effects, Occupational Health statistics & numerical data, Overweight, Work Schedule Tolerance psychology, Workload psychology
- Abstract
Background: The aim of the study was to examine the relationship between psychosocial and other working conditions and body-mass index (BMI) in a working population. This study contributes to the approximately dozen investigations of job stress, which have demonstrated mixed positive and negative results in relation to obesity, overweight and BMI., Methods: A cross-sectional population-based survey was conducted among working Australians in the state of Victoria. Participants were contacted by telephone from a random sample of phone book listings. Information on body mass index was self-reported as were psychosocial work conditions assessed using the demand/control and effort/reward imbalance models. Other working conditions measured included working hours, shift work, and physical demand. Separate linear regression analyses were undertaken for males and females, with adjustment for potential confounders., Results: A total of 1101 interviews (526 men and 575 women) were completed. Multivariate models (adjusted for socio-demographics) demonstrated no associations between job strain, as measured using the demand/control model, or ERI using the effort/reward imbalance model (after further adjustment for over commitment) and BMI among men and women. Multivariate models demonstrated a negative association between low reward and BMI among women. Among men, multivariate models demonstrated positive associations between high effort, high psychological demand, long working hours and BMI and a negative association between high physical demand and BMI. After controlling for the effort/reward imbalance or the demand/control model, the association between physical demand and working longer hours and BMI remained., Conclusion: Among men and women the were differing patterns of both exposures to psychosocial working conditions and associations with BMI. Among men, working long hours was positively associated with higher BMI and this association was partly independent of job stress. Among men physical demand was negatively associated with BMI and this association was independent of job stress.
- Published
- 2006
- Full Text
- View/download PDF
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