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Stephens AS, Dinh MM, Kinsman L. Patterns of emergency department use in rural and metropolitan New South Wales by socioeconomic status: A population-based study. Emerg Med Australas 2022; 35:489-495. [PMID: 36571146 DOI: 10.1111/1742-6723.14155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/24/2022] [Accepted: 12/01/2022] [Indexed: 12/27/2022]
Abstract
OBJECTIVE To investigate the patterns of ED use in metropolitan and rural New South Wales (NSW) by socioeconomic status (SES). METHODS We undertook a retrospective, population-based study of de-identified data from the NSW Emergency Department Data Collection (EDDC). The study population comprised of NSW residents who presented to an NSW public hospital ED in 2013-2019 and were registered in the NSW EDDC. Total ED presentations, negative binomial regression modelled annual changes in ED presentations over 2013-2019, and age- and sex-standardised rates of ED presentations in 2019 were assessed. RESULTS Overall, between 2013 and 2019, ED presentations increased in metropolitan and rural NSW, with mean annual percentage increases of 3.1% (95% confidence interval [CI] 2.8-3.5) and 2.5% (95% CI 2.0-2.9), respectively. This growth varied by SES, with larger increases observed in higher SES groups. The bulk of presentations in rural NSW were from individuals living in disadvantaged areas. Standardised rates of ED presentations were highest in the most disadvantaged quintiles (SES 1) and progressively decreased with increasing SES in both rural and metropolitan NSW (negative gradients). Rates were higher in rural NSW compared to metropolitan NSW across all SES quintiles for total, low acuity and non-low acuity presentations. CONCLUSIONS Negative gradients in rates of ED presentations with increasing SES were observed in both metropolitan and rural NSW. At each SES quintile, rates of ED presentations were higher in rural compared to metropolitan areas. Further research exploring the underlying causal mechanisms leading to increased ED demand in rural NSW and socioeconomically disadvantaged populations is warranted.
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Affiliation(s)
- Alexandre S Stephens
- Northern New South Wales Local Health District, Lismore, New South Wales, Australia.,School of Public Health, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Michael M Dinh
- Emergency Department, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia.,Sydney Medical School, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Leigh Kinsman
- Mid North Coast Local Health District, Coffs Harbour, New South Wales, Australia.,School of Nursing and Midwifery, Faculty of Medicine and Health, The University of Newcastle, Newcastle, New South Wales, Australia
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Campbell B, Schultz L, Bryant E, Tsung JD, Lynam B, Stephens AS. A 'joint. Aust J Prim Health 2022; 28:164-171. [PMID: 35190023 DOI: 10.1071/py20309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 11/12/2021] [Indexed: 11/23/2022]
Abstract
Australia is facing a growing burden of knee and hip osteoarthritis (OA). To address this demand in northern New South Wales, a community health-based conservative OA joint management service was established in the Tweed Valley. This paper describes the design, implementation and initial evaluation of the service. Following the principles of clinical redesign, a diagnostic phase involving consultation with key stakeholders revealed several issues. OA patients could wait up to 9 months for review by orthopaedic specialist following GP referral and received limited information on how to conservatively manage their conditions. GPs were constrained by short consultations and had limited knowledge of the latest recommendations for the conservative treatment of OA. GPs also highlighted the limitations of outdated fax systems for communication, noting their preference for secure electronic messaging. Based on these findings, the Tweed Knee and Hip Arthritis Service was established. For patients not on a waiting list for surgery, the service provides evidence-based conservative management for knee or hip OA involving standardised assessment, education, exercise, self-management strategies and regular review. An analysis of a foundational cohort of patients demonstrated improvements in a suite of validated and standardised measures for pain and function, with improvements seen as early as 1 month and sustained for 6 months. The study findings support the introduction of integrated conservative OA management models of care directly available to primary healthcare providers.
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Affiliation(s)
- Brayden Campbell
- Northern New South Wales Local Health District, Tweed Heads, NSW 2485, Australia
| | - Luke Schultz
- Northern New South Wales Local Health District, Lismore, NSW 2480, Australia
| | - Evan Bryant
- Northern New South Wales Local Health District, Tweed Heads, NSW 2485, Australia
| | - Jason D Tsung
- Northern New South Wales Local Health District, Tweed Heads, NSW 2485, Australia
| | - Brett Lynam
- Healthy North Coast, North Coast Primary Health Network, Tweed Heads, NSW 2485, Australia
| | - Alexandre S Stephens
- Northern New South Wales Local Health District, Lismore, NSW 2480, Australia; and School of Public Health, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia; and School of Health and Human Sciences, Southern Cross University, Lismore, NSW 2480, Australia; and Corresponding author
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Powell KL, Stephens SR, Stephens AS. Cardiovascular risk factor mediation of the effects of education and Genetic Risk Score on cardiovascular disease: a prospective observational cohort study of the Framingham Heart Study. BMJ Open 2021; 11:e045210. [PMID: 33436477 PMCID: PMC7805364 DOI: 10.1136/bmjopen-2020-045210] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
OBJECTIVES Level of education and genetic risk are key predictors of cardiovascular disease (CVD). While several studies have explored the causal mechanisms of education effects, it remains uncertain to what extent genetic risk is mediated by established CVD risk factors. This study sought to investigate this and explored the mediation of education and genetic effects on CVD by established cardiovascular risk factors in the Framingham Heart Study (FHS). DESIGN Prospective observational cohort study. PARTICIPANTS 7017 participants from the FHS. SETTING Community-based cohort of adults in Framingham, Massachusetts, USA. PRIMARY OUTCOME MEASURE Incident CVD. The total effects of education and genetic predisposition using a 63-variant genetic risk score (GRS) on CVD, as well as those mediated by established CVD risk factors, were assessed via mediation analysis based on the counterfactual framework using Cox proportional hazards regression models. RESULTS Over a median follow-up time of 12.0 years, 1091 participants experienced a CVD event. Education and GRS displayed significant associations with CVD after adjustment for age and sex and the established risk factors smoking, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), body mass index, systolic blood pressure (SBP) and diabetes. For education effects, smoking, HDL-C and SBP were estimated to mediate 18.8% (95% CI 9.5% to 43%), 11.5% (95% CI 5.7% to 29.0%) and 4.5% (95% CI 1.6% to 13.3%) of the total effect of graduate degree, respectively, with the collective of all risk factors combined mediating 38.5% (95% 24.1% to 64.9%). A much smaller proportion of the effects of GRS were mediated by established risk factors combined (17.6%, 95% CI 2.4% to 35.7%), with HDL-C and TC mediating 11.5% (95% CI 6.2% to 21.5%) and 3.1% (95% CI 0.2% to 8.3%), respectively. CONCLUSIONS Unlike education inequalities, established risk factors mediated only a fraction of GRS effects on CVD. Further research is required to elucidate the underlying causal mechanisms of genetic contributions to CVD.
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Affiliation(s)
- Katie L Powell
- Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Queensland, Australia
| | - Sebastien R Stephens
- Orthopaedics, Gold Coast Hospital and Health Service, Southport, Queensland, Australia
- School of Medicine, Griffith University Faculty of Health, Gold Coast, Queensland, Australia
| | - Alexandre S Stephens
- Clinical Governance, Northern NSW Local Health District, Lismore, New South Wales, Australia
- School of Public Health, The University of Sydney Faculty of Medicine and Health, Sydney, New South Wales, Australia
- School of Health and Human Sciences, Southern Cross University, Lismore, New South Wales, Australia
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Lower T, Kinsman L, Dinh MM, Lyle D, Cheney R, Allan J, Munro A, Taylor B, Wiggers JH, Bailey A, Weller L, Jacob A, Stephens AS. Patterns of emergency department use in rural and metropolitan New South Wales from 2012 to 2018. Aust J Rural Health 2020; 28:490-499. [DOI: 10.1111/ajr.12668] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 08/17/2020] [Indexed: 12/31/2022] Open
Affiliation(s)
- Tony Lower
- Mid North Coast Local Health District Port Macquarie NSW Australia
| | - Leigh Kinsman
- Mid North Coast Local Health District Port Macquarie NSW Australia
- Faculty of Medicine and Health School of Nursing and Midwifery University of Newcastle Newcastle NSW Australia
| | - Michael M. Dinh
- New South Wales Institute of Trauma and Injury Management Sydney NSW Australia
- Faculty of Medicine and Health Sydney Medical School The University of Sydney Sydney NSW Australia
| | - David Lyle
- Broken Hill University Department of Rural Health Faculty of Medicine and Health School of Medicine The University of Sydney Sydney NSW Australia
| | - Richard Cheney
- Western New South Wales Local Health District Orange NSW Australia
| | - Julaine Allan
- Western New South Wales Local Health District Orange NSW Australia
| | - Alice Munro
- Western New South Wales Local Health District Orange NSW Australia
| | - Barbara Taylor
- Murrumbidgee Local Health District Wagga Wagga NSW Australia
| | - John H. Wiggers
- Faculty of Medicine and Health School of Medicine, and Public Health University of Newcastle Newcastle NSW Australia
- Hunter New England Local Health District New Lambton NSW Australia
| | - Andrew Bailey
- Mid North Coast Local Health District Port Macquarie NSW Australia
| | - Lauren Weller
- New South Wales Rural Health Research Alliance Port Macquarie NSW Australia
| | - Alycia Jacob
- Faculty of Medicine and Health School of Nursing and Midwifery University of Newcastle Newcastle NSW Australia
| | - Alexandre S. Stephens
- Northern New South Wales Local Health District Lismore NSW Australia
- Faculty of Medicine and Health School of Public Health The University of Sydney Sydney NSW Australia
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Cavanagh K, Quinn E, Stephens AS, Najjar Z, Huhtinen E, Gupta L. Evaluation of enhanced follow-up for pertussis in children aged 5-9 years in Sydney Local Health District, NSW. Commun Dis Intell (2018) 2019. [DOI: 10.33321/cdi.2019.43.24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This article describes the evaluation of enhanced surveillance that was conducted on an older age-group of children with pertussis (ages 5-9 years), in addition to the routine follow-up of a younger age-group (ages 0-4 years) in Sydney Local Health District during 2015. We found little incremental benefit in this policy in terms of identifying additional high-risk contacts, despite a greatly increased workload.
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Affiliation(s)
- Kwendy Cavanagh
- Sydney Local Health District, Public Health Unit, Royal Prince Alfred Hospital, Missenden Road, Camperdown, Sydney, NSW, Australia
| | - Emma Quinn
- Sydney Local Health District, Public Health Unit, Royal Prince Alfred Hospital, Missenden Road, Camperdown, Sydney, NSW, Australia
| | - Alexandre S Stephens
- Northern NSW Local Health District, Research Office, Murwillumbah District Hospital, Ewing Street, Murwillumbah, NSW, Australia
| | - Zeina Najjar
- Sydney Local Health District, Public Health Unit, Royal Prince Alfred Hospital, Missenden Road, Camperdown, Sydney, NSW, Australia
| | - Essi Huhtinen
- Sydney Local Health District, Public Health Unit, Royal Prince Alfred Hospital, Missenden Road, Camperdown, Sydney, NSW, Australia
| | - Leena Gupta
- Sydney Local Health District, Public Health Unit, Royal Prince Alfred Hospital, Missenden Road, Camperdown, Sydney, NSW, Australia
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Stephens AS, Broome RA. Impact of emergency department occupancy on waiting times, rates of admission and representation, and length of stay when hospitalised: A data linkage study. Emerg Med Australas 2018; 31:555-561. [DOI: 10.1111/1742-6723.13204] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 07/10/2018] [Accepted: 10/15/2018] [Indexed: 11/28/2022]
Affiliation(s)
- Alexandre S Stephens
- Public Health Observatory Sydney Local Health District, Sydney New South Wales Australia
- Faculty of Medicine and Health, School of Public Health, The University of Sydney Sydney New South Wales Australia
- Research Office, Northern New South Wales Local Health District Lismore New South Wales Australia
| | - Richard A Broome
- Public Health Observatory Sydney Local Health District, Sydney New South Wales Australia
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Powell KL, Carrozzi A, Stephens AS, Tasevski V, Morris JM, Ashton AW, Dona AC. Utility of metabolic profiling of serum in the diagnosis of pregnancy complications. Placenta 2018; 66:65-73. [PMID: 29884304 DOI: 10.1016/j.placenta.2018.04.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 03/21/2018] [Accepted: 04/08/2018] [Indexed: 01/07/2023]
Abstract
INTRODUCTION Currently there are no clinical screening tests available to identify pregnancies at risk of developing preeclampsia (PET) and/or intrauterine growth restriction (IUGR), both of which are associated with abnormal placentation. Metabolic profiling is now a stable analytical platform used in many laboratories and has successfully been used to identify biomarkers associated with various pathological states. METHODS We used nuclear magnetic resonance spectroscopy (NMR) to metabolically profile serum samples collected from 143 pregnant women at 26-41 weeks gestation with pregnancy outcomes of PET, IUGR, PET IUGR or small for gestational age (SGA) that were age-matched to normal pre/term pregnancies. RESULTS Spectral analysis found no difference in the measured metabolites from normal term, pre-term and SGA samples, and of 25 identified metabolites, only glutamate was marginally different between groups. Of the identified metabolites, 3-methylhistidine, creatinine, acetyl groups and acetate, were determined to be independent predictors of PET and produced area under the curves (AUC) = 0.938 and 0.936 for the discovery and validation sets. Only 3-hydroxybutyrate was determined to be an independent predictor of IUGR, however the model had low predictive power (AUC = 0.623 and 0.581 for the discovery and validation sets). CONCLUSIONS A sub-panel of metabolites had strong predictive power for identifying PET samples in a validation dataset, however prediction of IUGR was more difficult using the identified metabolites. NMR based metabolomics can identify metabolites strongly associated with disease and has the potential to be useful in developing early clinical screening tests for at risk pregnancies.
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Affiliation(s)
- Katie L Powell
- Division of Perinatal Research, Kolling Institute, Northern Sydney Local Health District, St Leonards, NSW, 2065, Australia; Sydney Medical School Northern, University of Sydney, NSW, 2006, Australia; Pathology North, NSW Health Pathology, Royal North Shore Hospital, St Leonards, NSW, 2065, Australia.
| | - Anthony Carrozzi
- Department of Cardiology, Kolling Institute, Northern Sydney Local Health District, St Leonards, NSW, 2065, Australia; Sydney Medical School Northern, University of Sydney, NSW, 2006, Australia
| | - Alexandre S Stephens
- Northern NSW Local Health District, Murwillumbah District Hospital, Murwillumbah, NSW, 2484, Australia; School of Public Health, Sydney Medical School, University of Sydney, NSW, 2006, Australia
| | - Vitomir Tasevski
- Division of Perinatal Research, Kolling Institute, Northern Sydney Local Health District, St Leonards, NSW, 2065, Australia; Pathology North, NSW Health Pathology, Royal North Shore Hospital, St Leonards, NSW, 2065, Australia
| | - Jonathan M Morris
- Division of Perinatal Research, Kolling Institute, Northern Sydney Local Health District, St Leonards, NSW, 2065, Australia; Sydney Medical School Northern, University of Sydney, NSW, 2006, Australia
| | - Anthony W Ashton
- Division of Perinatal Research, Kolling Institute, Northern Sydney Local Health District, St Leonards, NSW, 2065, Australia; Sydney Medical School Northern, University of Sydney, NSW, 2006, Australia
| | - Anthony C Dona
- Department of Cardiology, Kolling Institute, Northern Sydney Local Health District, St Leonards, NSW, 2065, Australia; Sydney Medical School Northern, University of Sydney, NSW, 2006, Australia
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Stephens AS, Blyth F, Gupta L, Broome RA. Age and cause-of-death contributions to area socioeconomic, sex and remoteness differences in life expectancy in New South Wales, 2010-2012. Aust N Z J Public Health 2018; 42:180-185. [DOI: 10.1111/1753-6405.12753] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 09/01/2017] [Accepted: 10/01/2017] [Indexed: 11/27/2022] Open
Affiliation(s)
- Alexandre S. Stephens
- Public Health Observatory; Sydney Local Health District; Sydney New South Wales
- School of Public Health; The University of Sydney; New South Wales
| | - Fiona Blyth
- Concord Clinical School, Faculty of Medicine; The University of Sydney; New South Wales
| | - Leena Gupta
- Public Health Unit; Sydney Local Health District; Sydney New South Wales
| | - Richard A. Broome
- Public Health Observatory; Sydney Local Health District; Sydney New South Wales
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Stephens AS, Broome RA. Patterns of low acuity patient presentations to emergency departments in New South Wales, Australia. Emerg Med Australas 2017; 29:283-290. [PMID: 28320067 DOI: 10.1111/1742-6723.12767] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 01/03/2017] [Accepted: 01/16/2017] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To explore the patterns of low acuity patient (LAP) presentations to EDs in New South Wales (NSW), Australia. METHODS Retrospective study of NSW public hospital ED presentations between January 2013 and December 2014 that were registered in the NSW Emergency Department Data Collection (n = 409 035). LAPs were defined according to the Australian Institute of Health and Welfare (AIHW), Sprivulis and multiple ACEM methods. Multivariable logistic regression was used to assess the adjusted odds of LAP ED presentation by a suite of sociodemographic factors. RESULTS The percentage of LAPs varied considerably by definition, being as high as 54.7% (inner regional areas) and as low as 3.2% (major cities) using revised ACEM methods modified to contain unlimited consultation times or consultation times of 15 min or less, respectively. For each method, higher proportions of LAPs were observed in inner regional and remote/very remote areas relative to major cities. LAP ED presentations, based on ACEM definition with 1 h or 15 min consultation times, were greater in younger patients, increased during out of business hours and weekends, and decreased with increasing general practitioner (GP) density. CONCLUSION The percentage of LAPs varied substantially by definition, and further work is required to validate the methods, particularly around the appropriateness of length of consultation time with ACEM, between different hospitals and remoteness areas. Age was strongly associated with low acuity, with substantial effects also observed for GP density, and attendances during out of hours and weekends.
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Affiliation(s)
- Alexandre S Stephens
- Public Health Observatory, Sydney Local Health District, Sydney, New South Wales, Australia
| | - Richard A Broome
- Public Health Observatory, Sydney Local Health District, Sydney, New South Wales, Australia
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Abstract
OBJECTIVES Despite being one of the healthiest countries in the world, Australia displays substantial mortality differentials by socioeconomic disadvantage, remoteness and sex. In this study, we examined how these mortality differentials translated to differences in life expectancy between 2001 and 2012. DESIGN AND SETTING Population-based study using mortality and estimated residential population data from Australia's largest state, New South Wales (NSW), between 2001 and 2012. Age-group-specific death rates by socioeconomic disadvantage quintile, remoteness (major cities vs regional and remote areas), sex and year were estimated via Poisson regression, and inputted into life table calculations to estimate life expectancy. RESULTS Life expectancy decreased with increasing socioeconomic disadvantage in males and females. The disparity between the most and least socioeconomically deprived quintiles was 3.77 years in males and 2.39 years in females in 2012. Differences in life expectancy by socioeconomic disadvantage were mostly stable over time. Gender gaps in life expectancy ranged from 3.50 to 4.93 years (in 2012), increased with increasing socioeconomic disadvantage and decreased by ∼1 year for all quintiles between 2001 and 2012. Overall, life expectancy varied little by remoteness, but was 1.8 years higher in major cities compared to regional/remote areas in the most socioeconomically deprived regions in 2012. CONCLUSIONS Socioeconomic disadvantage and sex were strongly associated with life expectancy. The disparity in life expectancy across the socioeconomic spectrum was larger in males and was stable over time. In contrast, gender gaps reduced for all quintiles between 2001 and 2012, and a remoteness effect was evident in 2012, but only for those living in the most deprived areas.
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Affiliation(s)
- Alexandre S Stephens
- Public Health Observatory, Sydney Local Health District, Sydney, New South Wales, Australia
| | - Leena Gupta
- Public Health Observatory, Sydney Local Health District, Sydney, New South Wales, Australia
| | - Sarah Thackway
- Centre for Epidemiology and Evidence, NSW Ministry of Health, Sydney, New South Wales, Australia
| | - Richard A Broome
- Public Health Observatory, Sydney Local Health District, Sydney, New South Wales, Australia
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Stephens AS, Lain SJ, Roberts CL, Bowen JR, Nassar N. Association of Gestational Age and Severe Neonatal Morbidity with Mortality in Early Childhood. Paediatr Perinat Epidemiol 2016; 30:583-593. [PMID: 27774646 DOI: 10.1111/ppe.12323] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Although infant and child mortality rates have decreased substantially worldwide over the past two decades, efforts continue in many nations to further these declines. The identification of pertinent perinatal factors that are associated with early childhood mortality would help with these efforts. We investigated the association of two crucial perinatal factors, gestational age and severe neonatal morbidity at birth, with mortality during infancy (29-364 days) and early childhood (1-5 years). METHODS The study population included all singleton livebirths, ≥32 weeks' gestation in New South Wales, Australia in 2001-11. Birth data were linked to hospitalisation morbidity data and deaths data (linked birth cohort n = 871 916), and multivariable Cox regression models were used to assess mortality. RESULTS The median follow-up time per child was 4.95 years (range 0.00-5.92 years; 3 614 738 total person-years), with 984 deaths observed. Gestational age was associated with increased mortality, and specifically from deaths attributable to infections, respiratory conditions, and injuries during infancy, but not during early childhood. Severe neonatal morbidity strongly mediated the effects of gestational age during infancy, but not during early childhood, and was associated with increased mortality from circulatory, nervous, and respiratory system causes. CONCLUSIONS The direct effects of gestational age on mortality extended up to 1 year of age, whereas severe neonatal morbidity remained associated with heightened mortality into early childhood. Efforts to maximise the health and well-being of vulnerable infants, with emphasis on preventing infections and injuries, may help further reduce early childhood mortality.
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Affiliation(s)
- Alexandre S Stephens
- Clinical and Population Perinatal Health Research, Kolling Institute, Northern Sydney Local Health District, Sydney, NSW, Australia.,Sydney Medical School Northern, University of Sydney, Sydney, NSW, Australia.,Public Health Observatory, Sydney Local Health District, Sydney, NSW, Australia
| | - Samantha J Lain
- Clinical and Population Perinatal Health Research, Kolling Institute, Northern Sydney Local Health District, Sydney, NSW, Australia.,Sydney Medical School Northern, University of Sydney, Sydney, NSW, Australia.,Menzies Centre for Health Policy, School of Public Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Christine L Roberts
- Clinical and Population Perinatal Health Research, Kolling Institute, Northern Sydney Local Health District, Sydney, NSW, Australia.,Sydney Medical School Northern, University of Sydney, Sydney, NSW, Australia
| | - Jennifer R Bowen
- Sydney Medical School Northern, University of Sydney, Sydney, NSW, Australia.,Department of Neonatology, Royal North Shore Hospital, Sydney, NSW, Australia
| | - Natasha Nassar
- Clinical and Population Perinatal Health Research, Kolling Institute, Northern Sydney Local Health District, Sydney, NSW, Australia.,Sydney Medical School Northern, University of Sydney, Sydney, NSW, Australia.,Menzies Centre for Health Policy, School of Public Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
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Stephens AS, Morrison NA. Novel target genes of RUNX2 transcription factor and 1,25-dihydroxyvitamin D3. J Cell Biochem 2015; 115:1594-608. [PMID: 24756753 DOI: 10.1002/jcb.24823] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 04/21/2014] [Indexed: 01/15/2023]
Abstract
The RUNX2 transcription factor is indispensable for skeletal development and controls bone formation by acting as a signaling hub and transcriptional regulator to coordinate target gene expression. A signaling partner of RUNX2 is the nuclear vitamin D receptor (VDR) that becomes active when bound by its ligand 1,25-dihydroxyvitamin D3 (VD3). RUNX2 and VDR unite to cooperatively regulate the expression of numerous genes. In this study, we overexpressed RUNX2 in NIH3T3 fibroblasts concomitantly treated with VD3 and show that RUNX2 alone, or in combination with VD3, failed to promote an osteoblastic phenotype in NIH3T3 cells. However, the expression of numerous osteoblast-related genes was up-regulated by RUNX2 and large-scale gene expression profiling using microarrays identified over 800 transcripts that displayed a twofold of greater change in expression in response to RUNX2 overexpression or VD3 treatment. Functional analysis using gene ontology (GO) revealed GO terms for ossification, cellular motility, biological adhesion, and chromosome organization were enriched in the pool of genes regulated by RUNX2. For the set of genes whose expression was modulated by VD3, the GO terms response to hormone stimulus, chemotaxis, and metalloendopeptidase activity where overrepresented. Our study provides a functional insight into the consequences of RUNX2 overexpression and VD3 treatment in NIH3T3 cells in addition to identifying candidate genes whose expression is controlled by either factor individually or through their functional cooperation.
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Affiliation(s)
- Alexandre S Stephens
- School of Medical Science, Griffith University Gold Coast Campus, Southport, Queensland 4215, Australia
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Powell KL, Stephens AS, Ralph SJ. Development of a potent melanoma vaccine capable of stimulating CD8(+) T-cells independently of dendritic cells in a mouse model. Cancer Immunol Immunother 2015; 64:861-72. [PMID: 25893808 PMCID: PMC11028525 DOI: 10.1007/s00262-015-1695-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Accepted: 03/19/2015] [Indexed: 10/23/2022]
Abstract
At present, there are no vaccines approved for the prevention or treatment of malignant melanoma, despite the amount of time and resources that has been invested. In this study, we aimed to develop a self-contained vaccine capable of directly stimulating anticancer CD8(+) T-cell immune responses. To achieve this, three whole-cell melanoma vaccines were developed expressing 4-1BBL or B7.1 T-cell co-stimulatory molecules individually or in combination. The ability of engineered vaccine cell lines to stimulate potent anticancer immune responses in C57BL/6 mice was assessed. Mice vaccinated with cells overexpressing both 4-1BBL and B7.1 (B16-F10-4-1BBL-B7.1-IFNγ/β anticancer vaccine) displayed the greatest increases in CD8(+) T-cell populations (1.9-fold increase versus control within spleens), which were efficiently activated following antigenic stimulation, resulting in a 10.7-fold increase in cancer cell cytotoxicity relative to control. The enhanced immune responses in B16-F10-4-1BBL-B7.1-IFNγ/β-vaccinated mice translated into highly efficient rejection of live tumour burdens and conferred long-term protection against repeated tumour challenges, which were likely due to enhanced effector memory T-cell populations. Similar results were observed when dendritic cell (DC)-deficient LTα(-/-) mice were treated with the B16-F10-4-1BBL-B7.1-IFNγ/β anticancer vaccine, suggesting that the vaccine can directly stimulate CD8(+) T-cell responses in the context of severely reduced DCs. This study shows that the B16-F10-4-1BBL-B7.1-IFNγ/β anticancer vaccine acted as a highly effective antigen-presenting cell and is likely to be able to directly stimulate CD8(+) T-cells, without requiring co-stimulatory signals from either CD4(+) T-cells or DCs, and warrants translation of this technology into the clinical setting.
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Affiliation(s)
- Katie L Powell
- School of Medical Science, Griffith University, Gold Coast, QLD, Australia,
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Stephens AS, Lain SJ, Roberts CL, Bowen JR, Simpson JM, Nassar N. Hospitalisations from 1 to 6 years of age: effects of gestational age and severe neonatal morbidity. Paediatr Perinat Epidemiol 2015; 29:241-9. [PMID: 25846900 DOI: 10.1111/ppe.12188] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND To investigate whether the adverse infant health outcomes associated with early birth and severe neonatal morbidity (SNM) persist beyond the first year of life and impact on paediatric hospitalisations for children up to 6 years of age. METHODS The study population included all singleton live births, >32 weeks gestation in New South Wales, Australia, in 2001-2005, with follow-up to 6 years of age. Birth data were probabilistically linked to hospitalisation data (n = 392 964). The odds of hospitalisation, mean hospital length of stay (LOS) and costs, and cumulative LOS were evaluated by gestational age and SNM using multivariable analyses. RESULTS A total of 74 341 (18.9%) and 41 404 (10.5%) infants were hospitalised once and more than once, respectively. SNM was associated with increased odds of hospitalisation once (adjusted odds ratio [aOR] 1.16 [95% confidence interval 1.10, 1.22]) and more than once [aOR 1.51 (1.43, 1.61)]. Decreasing gestational age was associated with increasing odds of hospitalisation more than once from aOR 1.19 at 37-38 weeks to 1.49 at 33-34 weeks. Average LOS and costs per hospital admission were increased with SNM but not with decreasing gestational age. Cumulative LOS was significantly increased with SNM and decreasing gestational age. CONCLUSIONS Adverse effects of SNM and early birth persist between 1 and 6 years of age. Strategies to prevent early birth and reduce SNM, and to increase health monitoring of vulnerable infants throughout childhood may help reduce paediatric hospitalisations.
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Affiliation(s)
- Alexandre S Stephens
- NSW Biostatistical Officer Training Program, NSW Ministry of Health, Sydney, NSW, Australia; Kolling Institute of Medical Research, Clinical and Population Perinatal Health Research, University of Sydney, Sydney, NSW, Australia
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15
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Stephens AS, Toson B, Close JCT. Current and future burden of incident hip fractures in New South Wales, Australia. Arch Osteoporos 2014; 9:200. [PMID: 25385340 DOI: 10.1007/s11657-014-0200-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 10/29/2014] [Indexed: 02/03/2023]
Abstract
UNLABELLED Population ageing presents significant challenges for many developed nations. Accurately forecasting the likely future burden of age-related medical conditions, such as hip fracture, is critical. In this study, we present estimates of the current and future burden of hip fracture in NSW, Australia, providing crucial information for future health care planning. PURPOSE The aims of this study were to investigate the burden of hip fracture in Australia's largest state, New South Wales (NSW), and to build a prediction model to forecast the likely future burden of hip fracture from 2016 to 2036 in persons aged 50 years or more. METHODS A retrospective population-based cohort study was conducted using NSW hospitalisation data. Standardised incident hip fracture rates and hip fracture-related acute care length of stay and costs were estimated. Predictive negative binomial regression modelling using age, gender and local health district and year covariates together with projected NSW populations was applied to forecast future hip fractures. RESULTS Total incident hip fractures increased 8.8 % over a 12-year period from 2000/2001 to 2011/2012 despite declining age-standardised rates. Estimates of acute care length of stay for the treatment of hip fracture ranged from 10 to 15 days and acute care costs ranged between 21 and 29,000 Australian dollars per fracture. By 2036, incident hip fractures are projected to rise by 35.2 %, assuming a continued decline in the rate of hip fracture or by 107.5 % if the current decline in the rate does not continue. Acute care length of stay and costs are each predicted to rise between 37.1 and 110.4 % by 2036. CONCLUSION An ageing population and changing demographics will continue to drive the increasing burden of incident hip fractures in NSW and Australia in the foreseeable future. These anticipated changes provide important information for the planning and management of future hip fracture care.
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Affiliation(s)
- Alexandre S Stephens
- NSW Biostatistical Officer Training Program, NSW Ministry of Health, North Sydney, New South Wales, Australia,
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16
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Stephens AS, Purdie S, Yang B, Moore H. Life expectancy estimation in small administrative areas with non-uniform population sizes: application to Australian New South Wales local government areas. BMJ Open 2013; 3:e003710. [PMID: 24302503 PMCID: PMC3856616 DOI: 10.1136/bmjopen-2013-003710] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To determine a practical approach for deriving life expectancy estimates in Australian New South Wales local government areas which display a large diversity in population sizes. DESIGN Population-based study utilising mortality and estimated residential population data. SETTING 153 local government areas in New South Wales, Australia. OUTCOME MEASURES Key performance measures of Chiang II, Silcocks, adjusted Chiang II and Bayesian random effects model methodologies of life expectancy estimation including agreement analysis of life expectancy estimates and comparison of estimate SEs. RESULTS Chiang II and Silcocks methods produced almost identical life expectancy estimates across a large range of population sizes but calculation failures and excessively large SEs limited their use in small populations. A population of 25 000 or greater was required to estimate life expectancy with SE of 1 year or less using adjusted Chiang II (a composite of Chiang II and Silcocks methods). Data aggregation offered some remedy for extending the use of adjusted Chiang II in small populations but reduced estimate currency. A recently developed Bayesian random effects model utilising the correlation in mortality rates between genders, age groups and geographical areas markedly improved the precision of life expectancy estimates in small populations. CONCLUSIONS We propose a hybrid approach for the calculation of life expectancy using the Bayesian random effects model in populations of 25 000 or lower permitting the precise derivation of life expectancy in small populations. In populations above 25 000, we propose the use of adjusted Chiang II to guard against violations of spatial correlation, to benefit from a widely accepted method that is simpler to communicate to local health authorities and where its slight inferior performance compared with the Bayesian approach is of minor practical significance.
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Affiliation(s)
- Alexandre S Stephens
- NSW Biostatistical Officer Training Program, NSW Ministry of Health, Sydney, Australia
| | - Stuart Purdie
- Centre for Epidemiology and Evidence, NSW Ministry of Health, Sydney, Australia
| | - Baohui Yang
- Centre for Epidemiology and Evidence, NSW Ministry of Health, Sydney, Australia
| | - Helen Moore
- Centre for Epidemiology and Evidence, NSW Ministry of Health, Sydney, Australia
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17
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Rouf R, Stephens AS, Spaan L, Arndt NX, Day CJ, May TW, Tiralongo E, Tiralongo J. G₂/M cell cycle arrest by an N-acetyl-D-glucosamine specific lectin from Psathyrella asperospora. Glycoconj J 2013; 31:61-70. [PMID: 24072585 DOI: 10.1007/s10719-013-9502-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Revised: 09/17/2013] [Accepted: 09/17/2013] [Indexed: 10/26/2022]
Abstract
A new N-acetyl-D-glucosamine (GlcNAc) specific lectin was identified and purified from the fruiting body of the Australian indigenous mushroom Psathyrella asperospora. The functional lectin, named PAL, showed hemagglutination activity against neuraminidase treated rabbit and human blood types A, B and O, and exhibited high binding specificity towards GlcNAc, as well as mucin and fetuin, but not against asialofetuin. PAL purified to homogeneity by a combination of ammonium sulfate precipitation, chitin affinity chromatography and size exclusion chromatography, was monomeric with a molecular mass of 41.8 kDa, was stable at temperatures up to 55 °C and between pH 6-10, and did not require divalent cations for optimal activity. De novo sequencing of PAL using LC-MS/MS, identified 10 tryptic peptides that revealed substantial sequence similarity to the GlcNAc recognizing lectins from Psathyrella velutina (PVL) and Agrocybe aegerita (AAL-II) in both the carbohydrate binding and calcium binding sites. Significantly, PAL was also found to exert a potent anti-proliferative effect on HT29 cells (IC50 0.48 μM) that was approximately 3-fold greater than that observed on VERO cells; a difference found to be due to the differential expression of cell surface GlcNAc on HT29 and VERO cells. Further characterization of this activity using propidium iodine staining revealed that PAL induced cell cycle arrest at G2/M phase in a manner dependent on its ability to bind GlcNAc.
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Affiliation(s)
- Razina Rouf
- Institute for Glycomics, Griffith University, Gold Coast Campus, Griffith, QLD, 4222, Australia
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18
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Morrison NA, Stephens AS, Osato M, Pasco JA, Fozzard N, Stein GS, Polly P, Griffiths LR, Nicholson GC. Polyalanine repeat polymorphism in RUNX2 is associated with site-specific fracture in post-menopausal females. PLoS One 2013; 8:e72740. [PMID: 24086263 PMCID: PMC3781152 DOI: 10.1371/journal.pone.0072740] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 07/12/2013] [Indexed: 12/29/2022] Open
Abstract
Runt related transcription factor 2 (RUNX2) is a key regulator of osteoblast differentiation. Several variations within the RUNX2 gene have been found to be associated with significant changes in BMD, which is a major risk factor for fracture. In this study we report that an 18 bp deletion within the polyalanine tract (17A>11A) of RUNX2 is significantly associated with fracture. Carriers of the 11A allele were found to be nearly twice as likely to have sustained fracture. Within the fracture category, there was a significant tendency of 11A carriers to present with fractures of distal radius and bones of intramembranous origin compared to bones of endochondral origin (p = 0.0001). In a population of random subjects, the 11A allele was associated with decreased levels of serum collagen cross links (CTx, p = 0.01), suggesting decreased bone turnover. The transactivation function of the 11A allele showed a minor quantitative decrease. Interestingly, we found no effect of the 11A allele on BMD at multiple skeletal sites. These findings suggest that the 11A allele is a biologically relevant polymorphism that influences serum CTx and confers enhanced fracture risk in a site-selective manner related to intramembranous bone ossification.
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Affiliation(s)
- Nigel A. Morrison
- School of Medical Sciences, Griffith University, Gold Coast, Queensland, Australia
- * E-mail:
| | | | - Motomi Osato
- Centre for Translational Medicine, Cancer Science Institute, National University of Singapore, Singapore, Singapore
| | - Julie A. Pasco
- School of Medicine, Deakin University, Geelong, Victoria, Australia
| | - Nicolette Fozzard
- School of Medical Sciences, Griffith University, Gold Coast, Queensland, Australia
| | - Gary S. Stein
- Vermont Cancer Center for Basic and Translational Research, University of Vermont, Burlington, Vermont, United States of America
| | - Patsie Polly
- Department of Pathology and Inflammation and Infection Research Centre, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Lyn R. Griffiths
- School of Medical Sciences, Griffith University, Gold Coast, Queensland, Australia
| | - Geoff C. Nicholson
- Rural Clinical School, School of Medicine, The University of Queensland, Toowoomba, Queensland, Australia
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Maggioni A, von Itzstein M, Rodríguez Guzmán IB, Ashikov A, Stephens AS, Haselhorst T, Tiralongo J. Characterisation of CMP-sialic acid transporter substrate recognition. Chembiochem 2013; 14:1936-42. [PMID: 24014346 DOI: 10.1002/cbic.201300298] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Indexed: 11/05/2022]
Abstract
CMP-sialic acid transporter: We report an in-depth, multidisciplinary, structural study that has identified the amino acid residues intimately involved in CMP-sialic acid transporter (CST) substrate specificity. Our data provide a significant contribution towards a better understanding the structure-function relationship of this important family of transporters and the rational design of CST inhibitors.
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Affiliation(s)
- Andrea Maggioni
- Institute for Glycomics, Griffith University, Gold Coast Campus Queensland, 4222 (Australia)
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20
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Stephens AS, Day CJ, Tiralongo J. Optimized Conditions for the Delivery of Small Membrane Impermeable Compounds into Human Cells Using Hypotonic Shift. Cell 2012. [DOI: 10.4236/cellbio.2012.12005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Stephens AS, Stephens SR, Morrison NA. Internal control genes for quantitative RT-PCR expression analysis in mouse osteoblasts, osteoclasts and macrophages. BMC Res Notes 2011; 4:410. [PMID: 21996334 PMCID: PMC3204251 DOI: 10.1186/1756-0500-4-410] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Accepted: 10/14/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Real-time quantitative RT-PCR (qPCR) is a powerful technique capable of accurately quantitating mRNA expression levels over a large dynamic range. This makes qPCR the most widely used method for studying quantitative gene expression. An important aspect of qPCR is selecting appropriate controls or normalization factors to account for any differences in starting cDNA quantities between samples during expression studies. Here, we report on the selection of a concise set of housekeeper genes for the accurate normalization of quantitative gene expression data in differentiating osteoblasts, osteoclasts and macrophages. We implemented the use of geNorm, an algorithm that determines the suitability of genes to function as housekeepers by assessing expression stabilities. We evaluated the expression stabilities of 18S, ACTB, B2M, GAPDH, HMBS and HPRT1 genes. FINDINGS Our analyses revealed that 18S and GAPDH were regulated during osteoblast differentiation and are not suitable for use as reference genes. The most stably expressed genes in osteoblasts were ACTB, HMBS and HPRT1 and their geometric average constitutes a suitable normalization factor upon which gene expression data can be normalized. In macrophages, 18S and GAPDH were the most variable genes while HMBS and B2M were the most stably expressed genes. The geometric average of HMBS and B2M expression levels forms a suitable normalization factor to account for potential differences in starting cDNA quantities during gene expression analysis in macrophages. The expression stabilities of the six candidate reference genes in osteoclasts were, on average, more variable than that observed in macrophages but slightly less variable than those seen in osteoblasts. The two most stably expressed genes in osteoclasts were HMBS and B2M and the genes displaying the greatest levels of variability were 18S and GAPDH. Notably, 18S and GAPDH were the two most variably expressed control genes in all three cell types. The geometric average of HMBS, B2M and ACTB creates an appropriate normalization factor for gene expression studies in osteoclasts. CONCLUSION We have identified concise sets of genes suitable to use as normalization factors for quantitative real-time RT-PCR gene expression studies in osteoblasts, osteoclasts and macrophages.
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Affiliation(s)
- Alexandre S Stephens
- School of Medical Science, Griffith University, Gold Coast, Queensland, Australia.
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22
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Stephens AS, Stephens SR, Hobbs C, Hutmacher DW, Bacic-Welsh D, Woodruff MA, Morrison NA. Myocyte enhancer factor 2c, an osteoblast transcription factor identified by dimethyl sulfoxide (DMSO)-enhanced mineralization. J Biol Chem 2011; 286:30071-86. [PMID: 21652706 PMCID: PMC3191047 DOI: 10.1074/jbc.m111.253518] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Revised: 05/17/2011] [Indexed: 02/01/2023] Open
Abstract
Rapid mineralization of cultured osteoblasts could be a useful characteristic in stem cell-mediated therapies for fracture and other orthopedic problems. Dimethyl sulfoxide (DMSO) is a small amphipathic solvent molecule capable of stimulating cell differentiation. We report that, in primary human osteoblasts, DMSO dose-dependently enhanced the expression of osteoblast differentiation markers alkaline phosphatase activity and extracellular matrix mineralization. Furthermore, similar DMSO-mediated mineralization enhancement was observed in primary osteoblast-like cells differentiated from mouse mesenchymal cells derived from fat, a promising source of starter cells for cell-based therapy. Using a convenient mouse pre-osteoblast model cell line MC3T3-E1, we further investigated this phenomenon showing that numerous osteoblast-expressed genes were elevated in response to DMSO treatment and correlated with enhanced mineralization. Myocyte enhancer factor 2c (Mef2c) was identified as the transcription factor most induced by DMSO, among the numerous DMSO-induced genes, suggesting a role for Mef2c in osteoblast gene regulation. Immunohistochemistry confirmed expression of Mef2c in osteoblast-like cells in mouse mandible, cortical, and trabecular bone. shRNAi-mediated Mef2c gene silencing resulted in defective osteoblast differentiation, decreased alkaline phosphatase activity, and matrix mineralization and knockdown of osteoblast specific gene expression, including osteocalcin and bone sialoprotein. A flow on knockdown of bone-specific transcription factors, Runx2 and osterix by shRNAi knockdown of Mef2c, suggests that Mef2c lies upstream of these two important factors in the cascade of gene expression in osteoblasts.
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Affiliation(s)
- Alexandre S. Stephens
- From the School of Medical Science, Griffith University, Gold Coast Campus, Queensland 4215, Australia
| | - Sebastien R. Stephens
- From the School of Medical Science, Griffith University, Gold Coast Campus, Queensland 4215, Australia
| | - Carl Hobbs
- Guy's Campus, Kings College, WC2R 2LS London, United Kingdom, and
| | - Deitmar W. Hutmacher
- the Institute for Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland 4001, Australia
| | - Desa Bacic-Welsh
- From the School of Medical Science, Griffith University, Gold Coast Campus, Queensland 4215, Australia
| | - Maria Ann Woodruff
- the Institute for Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland 4001, Australia
| | - Nigel A. Morrison
- From the School of Medical Science, Griffith University, Gold Coast Campus, Queensland 4215, Australia
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23
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Kidd LJ, Stephens AS, Kuliwaba JS, Fazzalari NL, Wu ACK, Forwood MR. Temporal pattern of gene expression and histology of stress fracture healing. Bone 2010; 46:369-78. [PMID: 19836476 DOI: 10.1016/j.bone.2009.10.009] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Revised: 09/25/2009] [Accepted: 10/07/2009] [Indexed: 10/20/2022]
Abstract
Loading of the rat ulna is an ideal model to examine stress fracture healing. The aim of this study was to undertake a detailed examination of the histology, histomorphometry and gene expression of the healing and remodelling process initiated by fatigue loading of the rat ulna. Ulnae were harvested 1, 2, 4, 6, 8, and 10 weeks following creation of a stress fracture. Stress fracture healing involved direct remodelling that progressed along the fracture line as well as woven bone proliferation at the site of the fracture. Histomorphometry demonstrated rapid progression of basic multicellular units from 1 to 4 weeks with significant slowing down of healing by 10 weeks after loading. Quantitative PCR was performed at 4 hours, 24 hours, 4 days, 7 days, and 14 days after loading. Gene expression was compared to an unloaded control group. At 4 hours after fracture, there was a marked 220-fold increase (P<0.0001) in expression of IL-6. There were also prominent peak increases in mRNA expression for OPG, COX-2, and VEGF (all P<0.0001). At 24 hours, there was a peak increase in mRNA expression for IL-11 (73-fold increase, P<0.0001). At 4 days, there was a significant increase in mRNA expression for Bcl-2, COX-1, IGF-1, OPN, and SDF-1. At 7 days, there was significantly increased mRNA expression of RANKL and OPN. Prominent, upregulation of COX-2, VEGF, OPG, SDF-1, BMP-2, and SOST prior to peak expression of RANKL indicates the importance of these factors in mediating directed remodelling of the fracture line. Dramatic, early upregulation of IL-6 and IL-11 demonstrate their central role in initiating signalling events for remodelling and stress fracture healing.
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Affiliation(s)
- L J Kidd
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia.
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