34 results on '"Pollock NJ"'
Search Results
2. Neurofibrillary tangles of Alzheimer disease share antigenic determinants with the axonal microtubule-associated protein tau (?)
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Wood, JG, primary, Mirra, SS, additional, Pollock, NJ, additional, and Binder, LI, additional
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- 1987
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3. Mortality in Innu communities in Labrador, 1993-2018: a cross-sectional study of causes and location of death.
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Dawe R, Penashue J, Knight JC, Pike A, Benuen MP, Qupee A, and Pollock NJ
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- Humans, Newfoundland and Labrador epidemiology, Cross-Sectional Studies, Male, Female, Middle Aged, Aged, Adult, Adolescent, Infant, Child, Young Adult, Child, Preschool, Aged, 80 and over, Infant, Newborn, Respiratory Tract Diseases mortality, Cardiovascular Diseases mortality, Hospital Mortality trends, Arctic Regions epidemiology, Chronic Disease mortality, Chronic Disease epidemiology, Cause of Death, Mortality trends, Neoplasms mortality
- Abstract
In Canada, most people prefer to die at home. However, the proportion of deaths that occur in hospital has increased over time. This study examined mortality rates and proportionate mortality in Innu communities in Labrador, and compared patterns to other communities in Labrador and Newfoundland. We conducted a cross-sectional ecological study with mortality data from the vital statistics system. This included information about all deaths in Newfoundland and Labrador from 1993 to 2018. We used descriptive statistics and rates to examine patterns by age, sex, cause and location. During the 2003 to 2018 period the leading cause of death in the Innu communities (excluding external causes) was cancer, followed by circulatory disease and respiratory disease. Between 1993 and 2018, there was a lower percentage of hospital deaths and a higher percentage of at home deaths in Innu communities than in the rest of the province. The majority of deaths among Innu were due to cancer and chronic diseases. We found a higher percentage of at home deaths in Innu communities compared to the rest of the province.
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- 2024
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4. Hospitalizations and emergency department visits for self-harm in Canada during the first two years of the COVID-19 pandemic: A time series analysis.
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Liu L, Pollock NJ, Contreras G, Xu Y, and Thompson W
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- Male, Female, Humans, Pandemics, Time Factors, Emergency Room Visits, Canada epidemiology, Emergency Service, Hospital, Hospitalization, COVID-19 epidemiology, Self-Injurious Behavior epidemiology
- Abstract
Background: Rates of hospitalizations and emergency department (ED) visits due to self-harm are important indicators for understanding the impact of the COVID-19 pandemic on mental health. The objective of this study was to assess changes in self-harm hospitalizations and ED visits in Canada during the first two years of the pandemic., Methods: Rates of self-harm hospitalizations and ED visits during the pandemic were predicted based on regression analyses that modeled trends over a 5-year pre-pandemic period from fiscal year 2015 to 2019. The ratios of observed and model predicted (expected) rates in 2020 and 2021 were estimated separately to assess changes during the pandemic., Results: Overall, rates of self-harm hospitalizations and ED visits were lower than expected during the pandemic, especially in 2020. In 2021, rates for females returned to near-expected levels; but they remained lower than expected for males. Females aged 10-14 years had higher than expected rates. The rate ratio of observed rate over expected rate was 1.2 in 2020 but further increased to 1.8 in 2021 for both hospitalizations and ED visits. Higher than expected rates were also observed among females aged 15-19 years in 2021 only., Limitations: Suicide attempts and non-suicidal self-harm cases could not be distinguished., Conclusions: We observed lower than or close to expected rates of self-harm hospitalizations and ED visits during the pandemic for most population groups. The increased rates for young females highlights the importance of continued surveillance post-pandemic and targeted mental health services and suicide prevention programs., Competing Interests: Declaration of competing interest None., (Crown Copyright © 2024. Published by Elsevier B.V. All rights reserved.)
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- 2024
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5. Rates of out-of-home care among children in Canada: an analysis of national administrative child welfare data.
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Pollock NJ, Ouédraogo AM, Trocmé N, Hovdestad W, Miskie A, Crompton L, Campeau A, Tanaka M, Zhang C, Laprise C, and Tonmyr L
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- Child, Male, Adolescent, Humans, Foster Home Care, Cross-Sectional Studies, Child Welfare, Canada epidemiology, Home Care Services, Child Abuse
- Abstract
Introduction: As a part of the public health approach to child welfare, data about children placed in out-of-home care are needed to assess population trends, understand drivers of social and health inequities, and examine outcomes for children and families. We analyzed administrative data from Canada to describe the population of children in out-of-home care, and estimate and compare rates of out-of-home care by province/territory, year, sex/gender, age group and placement type., Methods: We conducted a cross-sectional analysis of point-in-time data from all provinces and territories for the period 2013/2014 to 2021/2022. We used frequencies and percentages to describe the population of children (and youth up to age 21 years) in out-of-home care and estimated overall and stratified rates and rate ratios., Results: An estimated 61 104 children in Canada were in out-of-home care on 31 March 2022. The national rate of out-of-home care was 8.24 children per 1000 population. Rate variations by province/territory were substantial and changed over time. Rates were highest among males and children aged 1 to 3 and 16 to 17 years. Foster homes were the most common type of placement, although kinship homes accounted for an increasing share., Conclusion: This analysis demonstrated that administrative data can be used to generate national indicators about children involved in the child welfare system. These data can be used for tracking progress towards health and social equity for children and youth in Canada., Competing Interests: The authors have no conflicts of interest to declare.
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- 2024
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6. Suicidality and protective factors among sexual and gender minority youth and adults in Canada: a cross-sectional, population-based study.
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Liu L, Batomen B, Pollock NJ, Contreras G, Jackson B, Pan S, and Thompson W
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- Female, Humans, Adult, Adolescent, Suicidal Ideation, Cross-Sectional Studies, Protective Factors, Pandemics, Canada epidemiology, COVID-19 epidemiology, Suicide, Sexual and Gender Minorities
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Background: Sexual and gender minority populations experience elevated risks for suicidality. This study aimed to assess prevalence and disparities in non-fatal suicidality and potential protective factors related to social support and health care access among sexual and gender minority youth and adults and their heterosexual and cisgender counterparts in Canada. The second objective was to examine changes in the prevalence of suicidal ideation and protective factors during the COVID-19 pandemic., Methods: Pooled data from the 2015, 2016 and 2019 Canadian Community Health Surveys were used to estimate pre-pandemic prevalence of suicidal ideation, plans and attempts, and protective factors. The study also estimated changes in the prevalence of recent suicidal ideation and protective factors in fall 2020, compared with the same period pre-pandemic., Results: The prevalence of suicidality was higher among the sexual minority populations compared with the heterosexual population, and the prevalence was highest among the bisexual population, regardless of sex or age group. The pre-pandemic prevalence of recent suicidal ideation was 14.0% for the bisexual population, 5.2% for the gay/lesbian population, and 2.4% for the heterosexual population. The prevalence of lifetime suicide attempts was 16.6%, 8.6%, and 2.8% respectively. More than 40% of sexual minority populations aged 15-44 years had lifetime suicidal ideation; 64.3% and 36.5% of the gender minority population had lifetime suicidal ideation and suicide attempts. Sexual and gender minority populations had a lower prevalence of protective factors related to social support and health care access. The prevalence of recent suicidal ideation among sexual and gender minority populations increased in fall 2020, and they tended to experience longer wait times for immediate care needed., Conclusions: Sexual and gender minority populations had a higher prevalence of suicidality and less social support and health care access compared to the heterosexual and cisgender populations. The pandemic was associated with increased suicidal ideation and limited access to care for these groups. Public health interventions that target modifiable protective factors may help decrease suicidality and reduce health disparities., (© 2023. Crown.)
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- 2023
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7. Self-harm and rurality in Canada: an analysis of hospitalization data from 2015 to 2019.
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Mahinpey N, Pollock NJ, Liu L, Contreras G, and Thompson W
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- Male, Female, Humans, Suicide Prevention, Canada, Hospitalization, Self-Injurious Behavior epidemiology, Suicide
- Abstract
Purpose: The incidence of self-harm is an important indicator in suicide surveillance and a target outcome for suicide prevention. Self-harm rates vary by geographic location and rurality appears to be a risk factor. The objectives of this study were to estimate rates of self-harm hospitalization in Canada over a 5-year period by sex and age group, and examine relationships between self-harm and rurality., Methods: Hospitalizations related to self-harm were identified in a national dataset (the Discharge Abstract Database) for all patients aged 10 years or older who were discharged from hospital between 2015 and 2019. Self-harm hospitalization rates were calculated and stratified by year, sex, age group, and level of rurality, as measured using the Index of Remoteness. A Poisson regression was fit to estimate rate ratios for the levels of rurality., Results: Rates of self-harm hospitalization were higher for females than males across all levels of rurality and increased with each level for both sexes, except for among young males. The widest rural-to-urban disparities were observed for the 10-19 and 20-34-year old age groups. Females aged 10-19 in very remote areas had the highest self-harm hospitalization rate., Conclusion: The rate of self-harm hospitalization in Canada varied by sex, age group, and level of rurality. Clinical and community-based interventions for self-harm, such as safety planning and increased access to mental health services, should be tailored to the differential risks across geographic contexts., (© 2023. Crown.)
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- 2023
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8. Indigenous communities and the mental health impacts of land dispossession related to industrial resource development: a systematic review.
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Ninomiya MEM, Burns N, Pollock NJ, Green NTG, Martin J, Linton J, Rand JR, Brubacher LJ, Keeling A, and Latta A
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- Humans, Australia, Industrial Development, New Zealand, Mental Health, Indigenous Peoples
- Abstract
Globally, many resource extraction projects such as mines and hydroelectric dams are developed on the territories of Indigenous Peoples. Recognising land as a determinant of Indigenous Peoples' health, our objective is to synthesise evidence about the mental health impacts on Indigenous communities who experience land dispossession due to industrial resource development (mining, hydroelectric, petroleum, and agricultural). We systematically reviewed studies that focused on Indigenous land dispossession in Australia, Aotearoa (New Zealand), North and South America, and the Circumpolar North. We searched Scopus, Medline, Embase, PsycINFO, and Global Health on OVID for peer-reviewed articles published in English from database inception to Dec 31, 2020. We also searched for books, research reports, and scholarly journals specialising in Indigenous health or Indigenous research. We included documents that reported on primary research, focused on Indigenous Peoples in settler colonial states, and reported on mental health and industrial resource development. Of the 29 included studies, 13 were related to hydroelectric dams, 11 to petroleum developments, nine to mining, and two to agriculture. Land dispossession due to industrial resource development had predominantly negative mental health impacts on Indigenous communities. The impacts were consequences of colonial relations that threatened Indigenous identities, resources, languages, traditions, spirituality, and ways of life. Health impact assessment processes in industrial resource development must expressly consider risks and potential impacts on mental health and respect Indigenous rights by making knowledge about mental health risks a central component to decisions about free, prior, and informed consent., Competing Interests: Declaration of interests MEMN was contracted by West Moberly First Nations to do the systematic review. MEMN is the Tier 2 Canada Research Chair in Community-Driven Knowledge Mobilization and Pathways to Wellness, Canada. NB, NJP, NTGG, JM, JRR, and LJB were hired by MEMN on a contract basis through this funding. All other authors declare no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)
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- 2023
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9. Suicidal ideation among young adults in Canada during the COVID-19 pandemic: evidence from a population-based cross-sectional study.
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Liu L, Contreras G, Pollock NJ, Tonmyr L, and Thompson W
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- Humans, Young Adult, Cross-Sectional Studies, Pandemics, Risk Factors, Canada epidemiology, Suicidal Ideation, COVID-19 epidemiology
- Abstract
Using data from the 2020 and 2021 cycles of the Survey on COVID-19 and Mental Health,we examined suicidal ideation among adults in Canada aged 18 to 34 years. The prevalence of suicidal ideation among adults aged 18 to 34 years was 4.2% in fall 2020 and 8.0% in spring 2021. The subgroup of adults aged 18 to 24 years had the highest prevalence of suicidal ideation, 10.7%, in spring 2021. Prevalence varied by sociodemographic characteristics and tended to be higher among people living in materially deprived areas. Suicidal ideation was strongly associated with pandemic-related stressors respondents experienced., Competing Interests: The authors have no conflicts of interest.
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- 2023
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10. Pandemic-related impacts and suicidal ideation among adults in Canada: a population-based cross-sectional study.
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Liu L, Pollock NJ, Contreras G, Tonmyr L, and Thompson W
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- Adult, Humans, Cross-Sectional Studies, Pandemics, Risk Factors, Canada epidemiology, Suicidal Ideation, COVID-19 epidemiology, COVID-19 prevention & control
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Introduction: Recent evidence has suggested an increase in suicidal ideation during the COVID-19 pandemic. Our objectives were to estimate the likelihood of suicidal ideation among adults in Canada who experienced pandemic-related impacts and to determine if this likelihood changed during the pandemic., Methods: We analyzed pooled data for 18 936 adults 18 years or older who responded to two cycles of the Survey on COVID-19 and Mental Health collected from 11 September to 4 December 2020 and from 1 February to 7 May 2021. We estimated the prevalence of suicidal ideation since the pandemic began and conducted logistic regression to evaluate the likelihood of suicidal ideation by adults who experienced pandemic-related impacts, and by factors related to social risk, mental health status, positive mental health indicators and coping strategies., Results: Adults who had adverse pandemic-related experiences were significantly more likely to experience suicidal ideation; a dose-response relationship was evident. People who increased their alcohol or cannabis use, expressed concerns about violence in their home or who had moderate to severe symptoms of depression, anxiety or posttraumatic stress disorder also had significantly higher risk of suicidal ideation. The risk was significantly lower among people who reported high self-rated mental health, community belonging or life satisfaction, who exercised for their mental and/or physical health or who pursued hobbies., Conclusion: The COVID-19 pandemic has influenced suicidal ideation in Canada. Our study provides evidence for targeted public health interventions related to suicide prevention., Competing Interests: The authors declare no conflicts of interest.
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- 2023
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11. Fatal and non-fatal firearm-related injuries in Canada, 2016-2020: a population-based study using three administrative databases.
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Toigo S, Pollock NJ, Liu L, Contreras G, McFaull SR, and Thompson W
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Background: Firearms are a substantial cause of injury-related morbidity and mortality in Canada and globally, though evidence from contexts other than the USA is relatively limited. We examined deaths, hospitalizations and emergency department (ED) visits due to firearm-related injuries in Canada to identify population groups at increased risk of fatal and non-fatal outcomes., Methods: We conducted a population-based study using three national administrative databases on deaths, hospitalizations, and ED visits. ICD-10 codes were used to identify firearm-related injuries from January 1, 2016, through December 31, 2020. Fatal and non-fatal firearm injuries were classified as suicide/self-harm, homicide/assault, unintentional, undetermined or legal intervention injuries. We analyzed the data with counts, rates and proportions, stratified by sex, age group, province/territory, and year., Results: Over the 5-year period, we identified 4005 deaths, 3169 hospitalizations, and 2847 ED visits related to firearm injuries in various jurisdictions in Canada. Males comprised the majority of fatal and non-fatal injury cases. The highest rates of fatal and non-fatal firearm injuries were among 20- to 34-year-olds. The leading cause of fatal firearm injuries was self-harm (72.3%). For non-fatal firearm hospitalizations and ED visits, assault (48.8%) and unintentional injuries (62.8%) were the leading causes of injury. Rates varied by province and territory., Conclusions: Our results showed that males comprised the majority of fatal and non-fatal firearm injuries in Canada. The rates of both fatal and non-fatal firearm injuries were highest among the 20- to 34-year-old age group. This comprehensive overview of the epidemiology of firearm injuries in Canada provides baseline data for ongoing surveillance and policy evaluation related to public health interventions., (© 2023. Crown.)
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- 2023
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12. Sex differences in suicide mortality in Newfoundland and Labrador: An observational study with medical examiner data from 1997 to 2016.
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Wilson MM, Pollock NJ, Power ND, Karaivanov Y, Mulay S, and Reccord C
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- Age Distribution, Canada, Female, Humans, Male, Newfoundland and Labrador, Sex Characteristics, Sex Distribution, Young Adult, Coroners and Medical Examiners, Suicide
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Background: Globally, the suicide rate is two times higher for males than for females. Previous studies in Newfoundland and Labrador did not examine age-specific rates by sex. The objectives of this study were to determine suicide rates by sex and age group and to compare the demographic and clinical characteristics of males and females who died by suicide., Data and Methods: This observational study analyzed a routinely collected dataset based on all medical examiner-determined suicide deaths among people aged 10 years and older in Newfoundland and Labrador, Canada, between 1997 and 2016. Age-standardized and age-specific suicide rates and rate ratios were calculated based on the number of deaths during the period, and descriptive statistics were used to compare demographic and clinical characteristics between males and females., Results: The age-standardized suicide rate was 4.6 times higher among males than females and was higher for males in most age groups. Rates were highest in the young adult age groups for males (20 to 24 years) and females (35 to 39 years). Males who died by suicide were more likely to be from a rural community and to have died by firearm; females were more likely to die by self-poisoning and to have had a mental illness or substance use history., Interpretation: The results are broadly consistent with previous research, though this is the first study to report age-specific suicide rates among females across the life course in Newfoundland and Labrador. The results underscore the need to design public health and clinical interventions that account for sex differences in suicide risks.
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- 2022
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13. Impact on mental health and wellbeing in Indigenous communities due to land loss resulting from industrial resource development: protocol for a systematic review.
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Burns N, Linton J, Pollock NJ, Brubacher LJ, Green N, Keeling A, Latta A, Martin J, Rand J, and Morton Ninomiya ME
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- Humans, Indigenous Peoples, Population Groups, Systematic Reviews as Topic, Delivery of Health Care, Mental Health
- Abstract
Background: Indigenous Peoples are impacted by industrial resource development that takes place on, or near, their communities. Existing literature on impacts of industrial resource development on Indigenous Peoples primarily focus on physical health outcomes and rarely focus on the mental health impacts. To understand the full range of long-term and anticipated health impacts of industrial resource development on Indigenous communities, mental health impacts must be examined. It is well-established that there is a connection between the environment and Indigenous wellbeing, across interrelated dimensions of mental, physical, emotional, and spiritual health., Methods: This paper identifies how the Community Advisory Team and a team of Indigenous and settler scholars will conduct the review. The literature search will use the OVID interface to search Medline, Embase, PsycINFO, and Global Health databases. Non-indexed peer-reviewed journals related to Indigenous health or research will be scanned. Books and book chapters will be identified in the Scopus and PsycINFO databases. The grey literature search will also include Google and be limited to reports published by government, academic, and non-profit organizations. Reference lists of key publications will be checked for additional relevant publications, including theses, dissertations, reports, and other articles not retrieved in the online searches. Additional sources may be recommended by team members. Included documents will focus on Indigenous Peoples in North America, South America, Australia, Aotearoa New Zealand, and Circumpolar regions, research that reports on mental health, and research that is based on land loss connected to dams, mines, agriculture, or petroleum development. Literature that meets the inclusion criteria will be screened at the title/abstract and full-text stages by two team members in Covidence. The included literature will be rated with a quality appraisal tool and information will be extracted by two team members; a consensus of information will be reached and be submitted for analysis., Discussion: The synthesized evidence from this review is relevant for land use policy, health impact assessments, economic development, mental health service planning, and communities engaging in development projects., Systematic Review Registration: Registered in the International Prospective Register of Systematic Reviews (PROSPERO; Registration number CRD42021253720 )., (© 2022. The Author(s).)
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- 2022
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14. Prevalence of suicidal ideation among adults in Canada: Results of the second Survey on COVID-19 and mental health.
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Liu L, Pollock NJ, Contreras G, Tonmyr L, and Thompson W
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- Adult, British Columbia, Canada epidemiology, Female, Humans, Male, Mental Health, Prevalence, Risk Factors, Suicidal Ideation, COVID-19
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Introduction: Data from the first round of the nationally representative Survey on COVID-19 and Mental Health (SCMH) revealed that the prevalence of recent suicidal ideation in the fall of 2020 in Canada did not differ significantly from that in the pre-pandemic period in 2019. The objective of the present study was to reassess the prevalence of recent suicidal ideation in the spring of 2021., Methods: The prevalence of suicidal ideation among adults in Canada was examined using the 2021 SCMH (conducted between February 1 and May 7, 2021), and it was compared with the prevalence in the 2019 Canadian Community Health Survey. Unadjusted logistic regression analysis was used to assess the differential likelihood of reporting suicidal ideation in population subgroups., Results: Among adults in Canada, the prevalence of suicidal ideation since the pandemic began was 4.2%, which was significantly higher than the pre-pandemic prevalence of 2.7% in 2019. A statistically significant increase in prevalence was observed among females and males, age groups younger than 65, and several other sociodemographic groups, as well as in British Columbia, the Prairie provinces and Ontario. People who were younger than 65 years, were born in Canada, had lower educational attainment, or were never married were significantly more likely to report suicidal ideation than others during the pandemic., Conclusion: As the second year of the pandemic began, the prevalence of recent suicidal ideation in Canada was higher than it had been before the pandemic in 2019. Continuous monitoring of suicide-related outcomes and risks is necessary so that population-level changes can be detected and inform public health action.
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- 2022
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15. Patient healthcare experiences in the Northwest Territories, Canada: an analysis of news media articles.
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Cooper R, Pollock NJ, Affleck Z, Bain L, Hansen NL, Robertson K, and Chatwood S
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- Canada, Delivery of Health Care, Female, Humans, Northwest Territories, Travel, Medical Tourism
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The factors that influence patient healthcare experiences are complex and connected to place. In northern Canada, the socio-historical context and the inequitable distribution of health services are unique influences on patients. The objective of this study was to examine the characteristics of patient healthcare experiences as reported through news media in the Northwest Territories. We used a case series design to examine patient healthcare experiences reported in news media articles. We conducted a systematic search for articles published between 2008 and 2017 in the online database of a media outlet in the Northwest Territories. We used descriptive statistics to summarise the article characteristics and thematic analysis to understand patient experiences in 128 articles related to 71 cases. Most often, cases involved women, concerned mental health, suicidality, or chronic diseases, and were predominantly negative. Patient experiences included problems associated with medical travel, communication difficulties with providers, lack of cultural safety, and barriers in accessing care resulting in poor-quality care, particularly for Indigenous patients. Broadly, these experiences are rooted in the colonial history in the North. Understanding patient experiences and including Indigenous patients in health system decision-making can help focus policies and clinical care on cultural safety and equity.
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- 2021
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16. Suicide in Newfoundland and Labrador, Canada: a time trend analysis from 1981 to 2018.
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Pollock NJ, Liu L, Wilson MM, Reccord C, Power ND, Mulay S, Karaivanov Y, and Tonmyr L
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- Adolescent, Adult, Canada, Child, Cross-Sectional Studies, Female, Humans, Male, Newfoundland and Labrador epidemiology, Young Adult, Suicide, Vital Statistics
- Abstract
Background: The suicide rate in Canada decreased by 24% during the past four decades. However, rates vary between provinces and territories, and not all jurisdictions experienced the same changes. This study examined suicide rates over time in the province of Newfoundland and Labrador., Methods: We used cross-sectional surveillance data from the Canadian Vital Statistics Death Database to examine suicide rates in Newfoundland and Labrador from 1981 to 2018. We calculated annual age-standardized suicide mortality rates and used joinpoint regression to estimate the average annual percent change (AAPC) in suicide rates overall and by sex, age group, and means of suicide., Results: From 1981 to 2018, 1759 deaths by suicide were recorded among people in Newfoundland and Labrador. The age-standardized suicide mortality rate increased more than threefold over the study period, from 4.6 to 15.4 deaths per 100,000. The suicide rate was higher among males than females, and accounted for 83.1% of suicide deaths (n = 1462); the male-to-female ratio of suicide deaths was 4.9 to 1. The average annual percent change in suicide rates was higher among females than males (6.3% versus 2.0%). Age-specific suicide rates increased significantly for all age groups, except seniors (aged 65 or older); the largest increase was among youth aged 10 to 24 years old (AAPC 3.5; 95% CI, 1.6 to 5.5). The predominant means of suicide was hanging/strangulation/suffocation, which accounted for 43.8% of all deaths by suicide., Conclusions: The suicide rate in Newfoundland and Labrador increased steadily between 1981 and 2018, which was in contrast to the national rate decline. The disparity between the provincial and national suicide rates and the variations by sex and age underscore the need for a public health approach to prevention that accounts for geographic and demographic differences in the epidemiology of suicide.
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- 2021
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17. Rural family physician perspectives on communication with urban specialists: a qualitative study.
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Wilson MM, Devasahayam AJ, Pollock NJ, Dubrowski A, and Renouf T
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- Canada, Communication, Humans, Newfoundland and Labrador, Qualitative Research, Physicians, Family, Specialization
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Objective: Communication is a key competency for medical education and comprehensive patient care. In rural environments, communication between rural family physicians and urban specialists is an essential pathway for clinical decision making. The aim of this study was to explore rural physicians' perspectives on communication with urban specialists during consultations and referrals., Setting: Newfoundland and Labrador, Canada., Participants: This qualitative study involved semistructured, one-on-one interviews with rural family physicians (n=11) with varied career stages, geographical regions, and community sizes., Results: Four themes specific to communication in rural practice were identified. The themes included: (1) understanding the contexts of rural care; (2) geographical isolation and patient transfer; and (3) respectful discourse; and (4) overcoming communication challenges in referrals and consultations., Conclusions: Communication between rural family physicians and urban specialists is a critical task in providing care for rural patients. Rural physicians see value in conveying unique aspects of rural clinical practice during communication with urban specialists, including context and the complexities of patient transfers., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)
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- 2021
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18. Trends in Suicide Mortality in Canada by Sex and Age Group, 1981 to 2017: A Population-Based Time Series Analysis: Tendances de la mortalité par suicide au Canada selon le sexe et le groupe d'âge, 1981 - 2017 : Une analyse de séries chronologiques dans la population.
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Varin M, Orpana HM, Palladino E, Pollock NJ, and Baker MM
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- Adult, Canada epidemiology, Databases, Factual, Female, Humans, Male, Middle Aged, Suicide, Vital Statistics
- Abstract
Objectives: Suicide is a complex global public health issue. The objective of this study was to assess time trends in suicide mortality in Canada by sex and age group., Methods: We extracted data from the Canadian Vital Statistics Death Database for all suicide deaths among individuals aged 10 years and older based on International Statistical Classification of Diseases and Related Health Problems, Ninth Revision (E950-959; 1981 to 1999) and International Statistical Classification of Diseases and Related Health Problems, 10th Revision (X60-X84, Y87·0; 2000 to 2017) for a 37-year period, from 1981 to 2017. We calculated annual age-standardized, sex-specific, and age group-specific suicide mortality rates, and used Joinpoint Regression for time trend analysis., Results: The age-standardized suicide mortality rate in Canada decreased by 24.0% from 1981 to 2017. From 1981 to 2007, there was a significant annual average decrease in the suicide rate by 1.1% (95% confidence interval, -1.3 to -0.9), followed by no significant change between 2007 and 2017. From 1981 to 2017 and from 1990 to 2017, females aged 10 to 24 and 45 to 64 years old, respectively, had a significant increase in suicide mortality rates. However, males had the highest suicide mortality rates in all years in the study; the average male-to-female ratio was 3.4:1., Conclusion: The 3-decade decline in suicide mortality rates in Canada paralleled the global trend in rate reductions. However, since 2008, the suicide rate in Canada was relatively unchanged. Although rates were consistently higher among males, we found significant rate increases among females in specific age groups. Suicide prevention efforts tailored for adult males and young and middle-aged females could help reduce the suicide mortality rate in Canada.
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- 2021
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19. Global goals and suicide prevention in the Circumpolar North.
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Pollock NJ, Apok C, Concepcion T, Delgado RA Jr, Rasmus S, Chatwood S, and Collins PY
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The purpose of this selective narrative review is to provide an overview of suicide and suicide prevention in the Circumpolar North and the relevance of global strategies and policies to these themes. We conducted a selective review of the English language literature on Arctic Indigenous mental health, suicide, and suicide prevention. We briefly present the social context, epidemiology, and risk and protective factors for suicide in the Arctic, with a focus on Indigenous peoples. We highlight a recent collaborative, intergovernmental response to elevated suicide rates in this region, the Reducing the Incidence of Suicide in Indigenous Groups - Strengths United through Networks Initiative, which used a consensus methodology to identify key outcomes for evaluating suicide prevention interventions in the circumpolar context. In relation to the Sustainable Development Goals, we examine recent policy developments in Indigenous-led suicide prevention and identify opportunities for strengthening policy, community interventions, and research. Globally, suicide prevention is a public health priority, and reducing the number of suicide deaths is a key target for sustainable development. Although overall and country-specific suicide rates have decreased since 1990, there remains wide variation at the regional and local level. This is particularly evident in the Arctic region known as the Circumpolar North, where Indigenous peoples experience marked disparities in suicide risk and suicide deaths compared to non-Indigenous populations. The factors that influence these variations are complex and often rooted in the social and economic consequences of colonization. The integration of science, community-based and Indigenous knowledge, and policies that address upstream risks for suicide will play an important role in suicide prevention alongside the growing number of Indigenous suicide prevention strategies tailored for specific populations., Competing Interests: There are no conflicts of interest., (Copyright: © 2020 Indian Journal of Psychiatry.)
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- 2020
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20. Place, the Built Environment, and Means Restriction in Suicide Prevention.
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Pollock NJ
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- Humans, Public Health, Built Environment, Suicide Prevention
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Restricting access to lethal means is a key public health intervention for preventing suicide. Means restriction research has often focused on suicide methods that are modifiable through legislation or policy interventions. However, some of the most common methods such as hanging may not be sensitive to regulation. The aims of this paper are to examine built environment and place-based approaches to means restriction in suicide prevention, and further consider the connections between place, the environment, and suicide methods. To increase knowledge about specific methods and mechanisms of injury in suicide deaths, higher resolution data for surveillance and epidemiology is required. Data that can be used to better discern patterns about specific locations and materials used in suicide and self-harm will support efforts to uncover new directions for prevention.
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- 2019
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21. Tracking progress in suicide prevention in Indigenous communities: a challenge for public health surveillance in Canada.
- Author
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Pollock NJ, Healey GK, Jong M, Valcour JE, and Mulay S
- Subjects
- Adolescent, Adult, Canada epidemiology, Female, Health Surveys, Humans, Male, Suicidal Ideation, Young Adult, Population Groups psychology, Population Groups statistics & numerical data, Public Health Surveillance, Suicide ethnology, Suicide Prevention
- Abstract
Indigenous peoples in Canada experience disproportionate rates of suicide compared to non-Indigenous populations. Indigenous communities and organizations have designed local and regional approaches to prevention, and the federal government has developed a national suicide prevention framework. However, public health systems continue to face challenges in monitoring the population burden of suicide and suicidal behaviour. National health data systems lack Indigenous identifiers, do not capture data from some regions, and do not routinely engage Indigenous communities in data governance. These challenges hamper efforts to detect changes in population-level outcomes and assess the impact of suicide prevention activities. Consequently, this limits the ability to achieve public health prevention goals and reduce suicide rates and rate inequities.This paper provides a critical analysis of the challenges related to suicide surveillance in Canada and assesses the strengths and limitations of existing data infrastructure for monitoring outcomes in Indigenous communities. To better understand these challenges, we discuss the policy context for suicide surveillance and examine the survey and administrative data sources that are commonly used in public health surveillance. We then review recent data on the epidemiology of suicide and suicidal behaviour among Indigenous populations, and identify challenges related to national surveillance.To enhance capacity for suicide surveillance, we propose strategies to better track progress in Indigenous suicide prevention. Specifically, we recommend establishing an independent community and scientific governing council, integrating Indigenous identifiers into population health datasets, increasing geographic coverage, improving suicide data quality, comprehensiveness, and timeliness, and developing a platform for making suicide data accessible to all stakeholders. Overall, the strategies we propose can build on the strengths of the existing national suicide surveillance system by adopting a collaborative and inclusive governance model that recognizes the stake Indigenous communities have in suicide prevention.
- Published
- 2018
- Full Text
- View/download PDF
22. Global incidence of suicide among Indigenous peoples: a systematic review.
- Author
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Pollock NJ, Naicker K, Loro A, Mulay S, and Colman I
- Subjects
- Ethnicity statistics & numerical data, Geography, Humans, Incidence, Global Health statistics & numerical data, Population Groups statistics & numerical data, Suicide ethnology, Suicide statistics & numerical data
- Abstract
Background: Suicide is the second leading cause of death among adolescents worldwide, and is a major driver of health inequity among Indigenous people in high-income countries. However, little is known about the burden of suicide among Indigenous populations in low- and middle-income nations, and no synthesis of the global data is currently available. Our objective was to examine the global incidence of suicide among Indigenous peoples and assess disparities through comparisons with non-Indigenous populations., Methods: We conducted a systematic review of suicide rates among Indigenous peoples worldwide and assessed disparities between Indigenous and non-Indigenous populations. We performed text word and Medical Subject Headings searches in PubMed, MEDLINE, Embase, Cumulative Index of Nursing and Allied Health (CINAHL), PsycINFO, Latin American and Caribbean Health Sciences Literature (LILACS), and Scientific Electronic Library Online (SciELO) for observational studies in any language, indexed from database inception until June 1, 2017. Eligible studies examined crude or standardized suicide rates in Indigenous populations at national, regional, or local levels, and examined rate ratios for comparisons to non-Indigenous populations., Results: The search identified 13,736 papers and we included 99. Eligible studies examined suicide rates among Indigenous peoples in 30 countries and territories, though the majority focused on populations in high-income nations. Results showed that suicide rates are elevated in many Indigenous populations worldwide, though rate variation is common, and suicide incidence ranges from 0 to 187.5 suicide deaths per 100,000 population. We found evidence of suicide rate parity between Indigenous and non-Indigenous populations in some contexts, while elsewhere rates were more than 20 times higher among Indigenous peoples., Conclusions: This review showed that suicide rates in Indigenous populations vary globally, and that suicide rate disparities between Indigenous and non-Indigenous populations are substantial in some settings but not universal. Including Indigenous identifiers and disaggregating national suicide mortality data by geography and ethnicity will improve the quality and relevance of evidence that informs community, clinical, and public health practice in Indigenous suicide prevention.
- Published
- 2018
- Full Text
- View/download PDF
23. Reconciling community-based Indigenous research and academic practices: Knowing principles is not always enough.
- Author
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Morton Ninomiya ME and Pollock NJ
- Subjects
- Canada, Community-Based Participatory Research, Humans, Personal Autonomy, Research Design standards, Informed Consent ethics, Population Groups ethics, Research Design trends
- Abstract
Historically, Indigenous health research in Canada has failed to engage Indigenous peoples and communities as primary stakeholders of research evidence. Increasingly, research ethics and methodologies are being positioned as tools for Indigenous self-determination. In response, mainstream institutions have developed new ethical principles for research involving Indigenous people. While these transformations are necessary steps towards re-orienting research practices, they are not prescriptive. In this paper, we make visible three dilemmas from a case study in which Indigenous health research frameworks provided limited guidance or were unclear about how to balance community priorities with Indigenous research principles. We also discuss the strategies used to resolve each of these dilemmas. We draw examples from a project that examined the lived experiences of children and youth living with FASD and their caregivers. This project was conducted in collaboration with Sheshatshiu Innu First Nation, an Indigenous community in Labrador, Canada. In doing so, we argue that knowing the key guiding principles in Indigenous health research is not always enough, and that the 'real-world' context of practices and relationships can lead to conflicts that are not easily resolved with adherence to these principles., (Copyright © 2016 Elsevier Ltd. All rights reserved.)
- Published
- 2017
- Full Text
- View/download PDF
24. Suicide Rates in Aboriginal Communities in Labrador, Canada.
- Author
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Pollock NJ, Mulay S, Valcour J, and Jong M
- Subjects
- Adolescent, Adult, Age Distribution, Child, Female, Humans, Male, Middle Aged, Newfoundland and Labrador epidemiology, Politics, Residence Characteristics statistics & numerical data, Retrospective Studies, Sex Distribution, Socioeconomic Factors, Young Adult, Suicide Prevention, Indians, North American statistics & numerical data, Inuit statistics & numerical data, Suicide ethnology
- Abstract
Objectives: To compare suicide rates in Aboriginal communities in Labrador, including Innu, Inuit, and Southern Inuit, with the general population of Newfoundland, Canada., Methods: In partnership with Aboriginal governments, we conducted a population-based study to understand patterns of suicide mortality in Labrador. We analyzed suicide mortality data from 1993 to 2009 from the Vital Statistics Death Database. We combined this with community-based methods, including consultations with Elders, youths, mental health and community workers, primary care clinicians, and government decision-makers., Results: The suicide rate was higher in Labrador than in Newfoundland. This trend persisted across all age groups; however, the disparity was greatest among those aged 10 to 19 years. Males accounted for the majority of deaths, although suicide rates were elevated among females in the Inuit communities. When comparing Aboriginal subregions, the Innu and Inuit communities had the highest age-standardized mortality rates of, respectively, 165.6 and 114.0 suicides per 100 000 person-years., Conclusions: Suicide disproportionately affects Innu and Inuit populations in Labrador. Suicide rates were high among male youths and Inuit females.
- Published
- 2016
- Full Text
- View/download PDF
25. Backcountry Travel Emergencies in Arctic Canada: A Pilot Study in Public Health Surveillance.
- Author
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Young SK, Tabish TB, Pollock NJ, and Young TK
- Subjects
- Arctic Regions epidemiology, Canada epidemiology, Case Management, Climate Change, Female, Health Services Accessibility organization & administration, Humans, Male, Mass Media, Northwest Territories epidemiology, Nunavut epidemiology, Pilot Projects, Regional Health Planning, Travel, Emergencies epidemiology, Health Services Accessibility statistics & numerical data, Health Services, Indigenous organization & administration, Health Services, Indigenous statistics & numerical data, Medically Underserved Area, Population Groups, Public Health Surveillance methods
- Abstract
Residents in the Canadian Arctic regularly travel in remote, backcountry areas. This can pose risks for injuries and death, and create challenges for emergency responders and health systems. We aimed to describe the extent and characteristics of media-reported backcountry travel emergencies in two Northern Canadian territories (Nunavut and Northwest Territories). A case-series of all known incidents between 2004 and 2013 was established by identifying events in an online search of two media outlets, Nunatsiaq News and Northern News Services. We identified 121 incidents; these most commonly involved young men, and death occurred in just over 25% of cases. The territories differed in the seasonal patterns. News media provides a partial source of data to estimate the extent and characteristics of backcountry emergencies. This information is needed to improve emergency preparedness and health system responsiveness in the Arctic.
- Published
- 2016
- Full Text
- View/download PDF
26. Health transitions, fast and nasty: the case of Marshallese exposure to nuclear radiation.
- Author
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Pollock NJ
- Subjects
- Abnormalities, Radiation-Induced etiology, Female, Food Supply, Humans, Infant, Newborn, Male, Micronesia epidemiology, Neoplasms, Radiation-Induced etiology, Population Surveillance, Pregnancy radiation effects, Pregnancy Outcome, Radioactive Fallout adverse effects, United States, United States Government Agencies, Abnormalities, Radiation-Induced epidemiology, Environmental Exposure adverse effects, Health Transition, Neoplasms, Radiation-Induced epidemiology, Nuclear Warfare, Radioactive Pollutants toxicity
- Abstract
The concept of health transitions assumes that health status improves with the introduction of western medicine. In this paper I demonstrate that the health of the people of Rongelap, Marshall Islands, has undergone serious damage as a result of nuclear testing, and that women in particular have suffered unduly. Exposure to nuclear radiation over a period of almost fifty years has been recognised by US authorities as a major contributory cause to the high rates of cancers and birth defects suffered by the Rongelap people. Women's reproduction has been severely affected, as evidenced by the many stillbirths and small stature of children born alive. Two generations have been exposed to both background radiation and to radiation ingested with the local foods on which they rely in the absence of other food sources. Clean up has commenced only after this and other communities sought compensation from the United States. The Rongelap people will live with the effects of radiation for generations to come. This transition to ongoing health problems is thus a negative outcome of modern health transition.
- Published
- 2002
27. Obesity or large body size? A study in Wallis and Futuna.
- Author
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Pollock NJ
- Subjects
- Feeding Behavior ethnology, Female, Humans, Life Style ethnology, Polynesia, Body Constitution ethnology, Body Image, Obesity ethnology
- Published
- 2001
28. Cultural elaborations of obesity - fattening practices in Pacific societies.
- Author
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Pollock NJ
- Abstract
Fattening rituals in Pacific societies are examined within a discussion of the cultural aspects of obesity as a disease of modernisation. Those rituals contributed to a strong aesthetic value of large body size and light skin, while also incorporating the symbolic value of food. They may have enhanced survival value of a genetic potential in the face of irregular diet. Today with a more regular diet available only the negative aspects of large body size prevail.
- Published
- 1995
29. A D1/D2 chimeric dopamine receptor mediates a D1 response to a D2-selective agonist.
- Author
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MacKenzie RG, Steffey ME, Manelli AM, Pollock NJ, and Frail DE
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, Cell Line, Cloning, Molecular, DNA, Humans, Molecular Sequence Data, Quinpirole, Rats, Receptors, Dopamine D1 genetics, Receptors, Dopamine D2 genetics, Recombinant Fusion Proteins metabolism, Dopamine Agents metabolism, Ergolines metabolism, Receptors, Dopamine D1 metabolism, Receptors, Dopamine D2 metabolism
- Abstract
D1 and D2 dopamine receptors are G-protein coupled receptors and have seven transmembrane spanning regions (TM) typical of this receptor superfamily. Although dopamine binds equally to D1 and D2 receptors, many compounds are highly selective. To probe the receptors for regions that determine subtype specificity, plasmid constructs coding for the D1 or a D1/D2 chimeric receptor were made and transfected into cells to study the binding and agonist properties of non-selective or subtype-selective compounds. The results suggest that the D2-selective agonist, quinpirole, gains much of its selectivity by binding to within TM VI and VII of the D2 receptor.
- Published
- 1993
- Full Text
- View/download PDF
30. Serine mutations in transmembrane V of the dopamine D1 receptor affect ligand interactions and receptor activation.
- Author
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Pollock NJ, Manelli AM, Hutchins CW, Steffey ME, MacKenzie RG, and Frail DE
- Subjects
- Amino Acid Sequence, Animals, Binding Sites, Binding, Competitive, Cell Line, Cell Membrane ultrastructure, Dopamine metabolism, Dopamine Antagonists, Humans, Kinetics, Molecular Sequence Data, Mutagenesis, Site-Directed, Protein Conformation, Receptors, Dopamine genetics, Receptors, Dopamine D1, Restriction Mapping, Sequence Homology, Nucleic Acid, Transfection, Benzazepines metabolism, Cell Membrane metabolism, Dopamine Agents pharmacology, Receptors, Dopamine metabolism, Serine
- Abstract
Several serines present in transmembrane domain V are conserved among members of the G-protein-coupled receptor family that bind catecholamines. Two of these serines that are present in the beta-adrenergic receptor were previously shown by site-directed mutagenesis to affect agonist binding and receptor activation (Strader, C. D., Candelore, M. R., Hill, W. S., Sigal, I. S., and Dixon, R. A. F. (1989) J. Biol. Chem. 264, 13572-13578). We investigated the role of the serines present in transmembrane V of another catecholamine receptor, the dopamine D1 receptor, by site-directed mutagenesis, and the results show that mutations at serines 198, 199, and 202 affect dopamine binding. The substitution of serine 198 or serine 199 by an alanine also affects the binding of several other agonist and antagonist dopaminergic compounds while an alanine substitution at serine 202 has no effect on the binding of these compounds. Moreover, each single serine mutation decreased the maximal cAMP accumulation elicited by a dopamine D1 partial agonist. These results suggest that serines present in transmembrane V of the D1 receptor affect ligand interactions and receptor signal transduction, but not entirely in the manner that would be predicted from the model proposed for the beta-adrenergic receptor.
- Published
- 1992
31. Activation of the 5-HT1C receptor expressed in Xenopus oocytes by the benzazepines SCH 23390 and SKF 38393.
- Author
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Briggs CA, Pollock NJ, Frail DE, Paxson CL, Rakowski RF, Kang CH, and Kebabian JW
- Subjects
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine analogs & derivatives, Animals, Binding, Competitive drug effects, Choroid Plexus metabolism, Cloning, Molecular, Dopamine Agents pharmacology, Dopamine Antagonists, In Vitro Techniques, Oocytes drug effects, RNA, Messenger metabolism, Receptors, Dopamine drug effects, Receptors, Dopamine D1, Serotonin pharmacology, Signal Transduction drug effects, Swine, Xenopus laevis, 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine pharmacology, Benzazepines pharmacology, Oocytes metabolism, Receptors, Serotonin drug effects
- Abstract
1. A cloned 5-HT1C receptor expressed in Xenopus laevis oocytes was used to characterize the action of four dopamine D1-selective benzazepines at the 5-HT1C receptor. Additionally, the apparent binding of the D1-selective benzazepines to 5-HT1C receptors was measured in the choroid plexus of the pig. 2. In voltage-clamped oocytes expressing the cloned 5-HT1C receptor, 5-hydroxytryptamine (5-HT) elicited a characteristic inward current response with an EC50 of 13 nM. SCH 23390 acted as a stereoselective agonist (or partial agonist) with an EC50 of about 550 nM. SKF 38393 (1 microM-1 mM), SKF 77434 (100 microM), and SKF 82958 (100 microM) also acted as agonists (or partial agonists) at the cloned 5-HT1C receptor. SKF 38393 was not stereoselective at the 5-HT1C receptor. 3. The response to SCH 23390 activated slowly and, although the response contained many oscillations characteristic of the activation of the phosphatidylinositol signal transduction system, SCH 23390 rarely elicited the rapid spike-like response seen routinely in response to 5-HT. However, the responses to SKF 38393, SKF 77434, and SKF 82958 were identical in appearance to the response to 5-HT, except that the responses to the benzazepines were smaller. These comparisons were made by applying both a benzazepine and 5-HT to each individual oocyte expressing the cloned 5-HT1C receptor. 4. Consistent with the responses measured in oocytes, SCH 23390 bound stereoselectively to 5-HT1C receptors in the choroid plexus of the pig (Ki = 6.3 nM), and SKF 38393 bound non-stereoselectively with lower affinity (Ki = 2.0-2.2 microM).5. It is concluded that while these benzazepines demonstrate selectivity for the dopamine D1 receptor, they also can act as agonists or partial agonists at the 5-HT1c receptor in situ and as expressed in Xenopus oocytes. The oocyte expression system is useful for studies of the functional pharmacology of these 5-HTic receptors. Information about the pharmacological actions and variations in stereoselectivity among dopamine and 5-HT receptors should be of interest in modelling the interactions of ligands with these G-protein coupled receptors, and in the testing of such models through receptor mutagenesis.
- Published
- 1991
- Full Text
- View/download PDF
32. Filamentous aggregates in Pick's disease, progressive supranuclear palsy, and Alzheimer's disease share antigenic determinants with microtubule-associated protein, tau.
- Author
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Pollock NJ, Mirra SS, Binder LI, Hansen LA, and Wood JG
- Subjects
- Brain immunology, Cytoskeleton immunology, Humans, tau Proteins, Alzheimer Disease immunology, Dementia immunology, Epitopes analysis, Microtubule-Associated Proteins immunology, Supranuclear Palsy, Progressive immunology
- Published
- 1986
- Full Text
- View/download PDF
33. Neurofibrillary tangles of Alzheimer disease share antigenic determinants with the axonal microtubule-associated protein tau (tau)
- Author
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Wood JG, Mirra SS, Pollock NJ, and Binder LI
- Subjects
- Alzheimer Disease immunology, Antibodies, Monoclonal, Antibody Specificity, Axons pathology, Cytoskeleton immunology, Epitopes, Humans, Immunoenzyme Techniques, tau Proteins, Alzheimer Disease pathology, Cytoskeleton pathology, Microtubule-Associated Proteins immunology
- Abstract
The relationship of the neurofibrillary tangle, found in Alzheimer disease and aged brains, to normal or abnormal cytoskeletal proteins remains elusive. Although immunohistochemical studies have yielded disparate results, most antigenic determinants localized to neurofibrillary tangles are cytoskeletal constituents normally present in neuronal perikarya or dendrites. We report light and electron microscopic immunolabeling of neurofibrillary tangles by a monoclonal antibody to the microtubule-associated protein tau (tau). Dephosphorylation of tissue slices not only increased the number of tau-positive tangles but also produced marked positive immunoreactivity of neuritic plaques. The localization of tau, an axonal protein, to neurofibrillary tangles in the perikaryon in particular suggests that abnormal synthesis, modification, or aggregation of tau may induce aberrant cytoskeletal--cell organelle interactions, subsequent interference with axonal flow, and resultant tangle formation.
- Published
- 1986
- Full Text
- View/download PDF
34. Differential sensitivity of the microtubule-associated protein, tau, in Alzheimer's disease tissue to formalin fixation.
- Author
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Pollock NJ and Wood JG
- Subjects
- Alzheimer Disease pathology, Axons analysis, Densitometry, Fixatives, Humans, Immunoassay, Immunohistochemistry, Lysine, Periodic Acid, tau Proteins, Alzheimer Disease metabolism, Formaldehyde, Microtubule-Associated Proteins analysis, Nerve Tissue Proteins analysis, Neurofibrils analysis
- Abstract
Immunohistochemistry of formalin-fixed human Alzheimer's disease (AD) tissue using an anti-tau antibody (Tau-1) reveals staining of neurofibrillary tangles (NFTs) and neuritic plaques (NPs), whereas normal axonal staining is less apparent. In this study, we used a combined biochemical and histochemical approach to assess effects of formalin on immunoreactivity of AD tau. Nitrocellulose blots were treated with fixative to mimic conditions used with tissue sections, a method that might be generally useful for assessing antigen sensitivity to different fixatives. A progressive decrease in Tau-1 immunoreactivity of the tau bands on a Western blot was observed with increasing times of formalin fixation. Phosphatase-digested blots demonstrated an increase in Tau-1 immunoreactivity compared to control blots. These results mimic the phosphatase-sensitive Tau-1 immunohistochemical staining of formalin-fixed AD tissue slices previously reported. Fixation of AD tissue with periodate-lysine-paraformaldehyde (PLP) preserves axonal tau antigenicity. Phosphatase digestion of PLP-fixed AD tissue enhances Tau-1 immunoreactivity of NFTs and NPs but does not alter axonal staining. These results indicate that axonal form(s) of tau are more sensitive to formalin fixation than pathology-associated tau. In addition, a modification of AD tau in pathological structures may protect it from the effects of formalin with regard to Tau-1 antigenicity.
- Published
- 1988
- Full Text
- View/download PDF
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