11 results on '"A. Tonkin"'
Search Results
2. What can it achieve?
- Author
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Tonkin, Ray
- Published
- 2022
3. A synthesis of 15 years of instream woody habitat management: Progress towards benchmarks and assessing fish responses.
- Author
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Hale, Robin, Kitchingman, Adrian, Sharley, Joanne, Reich, Paul, and Tonkin, Zeb
- Subjects
STREAM restoration ,HABITATS ,FRESHWATER fishes - Abstract
There is increasing focus globally on restoration actions to mitigate the effects of humans on freshwater ecosystems. Given the substantial investments in these actions, there is a need to determine if they meet their intended ecological outcomes. Setting benchmarks and rigorous monitoring of responses to actions are essential but are often not undertaken.Addition of instream woody habitat (IWH) is one of the most common stream rehabilitation techniques globally, particularly with the aim of enhancing fish populations. We present a synthesis of IWH interventions undertaken over a 15‐year period across the state of Victoria, in south‐eastern Australia. We collated data from 275 rivers on past IWH densities and, using benchmarks that had been set in earlier work, we examined how much current IWH levels deviated from this benchmark (Aim 1), as a way of assessing where IWH is degraded relative to estimated natural levels, and quantified progress towards achieving IWH benchmarks (Aim 2). We then used data from 25 intervention projects to assess fish responses to IWH additions using a meta‐analysis (Aim 3), including exploring the role of several predictors (time since intervention, baseline habitat density) on the magnitude of these responses.Many rivers had lower IWH densities than their benchmarks. The density of IWH had increased by less than 20% in many waterways where IWH had been added. However, at some locations, IWH additions had led to density increases of more than 40%. Fish responses to IWH additions were mixed overall but we found evidence that positive effects are more likely at locations older than 8 years post‐intervention, and those in areas with higher IWH density prior to additions.Our study highlighted: (1) deriving benchmarks can help set clear management targets, and facilitate meaningful evaluation of progress; and (2) fish responses to IWH additions may take several years (at least) to occur, and response trajectories can be non‐linear, including the potential for short‐term negative outcomes. Therefore, a long‐term commitment to monitoring and evaluation is needed. Consideration of these points will help river managers decide where to focus their efforts to maximise ecological responses to IWH additions and other restoration actions more broadly. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
4. Cultural tourism: Observations of a bureaucratic experience
- Author
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Tonkin, Ray
- Published
- 1990
5. Key Role of Suppressor of Cytokine Signaling 3 in Regulating gp130 Cytokine-Induced Signaling and Limiting Chondrocyte Responses During Murine Inflammatory Arthritis.
- Author
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Liu, Xiao, Croker, Ben A., Campbell, Ian K., Gauci, Stephanie J., Alexander, Warren S., Tonkin, Brett A., Walsh, Nicole C., Linossi, Edmond M., Nicholson, Sandra E., Lawlor, Kate E., and Wicks, Ian P.
- Subjects
ACADEMIC medical centers ,ANALYSIS of variance ,ANIMAL experimentation ,ARTHRITIS ,CYTOKINES ,FLOW cytometry ,MICE ,POLYMERASE chain reaction ,RESEARCH funding ,STATISTICS ,T-test (Statistics) ,DATA analysis ,MANN Whitney U Test - Abstract
Objective To examine the impact of the gp130 cytokine family on murine articular cartilage and to explore a potential regulatory role of suppressor of cytokine signaling 3 (SOCS-3) in murine chondrocytes. Methods In wild-type (WT) mouse chondrocytes, baseline receptor expression levels and gp130 cytokine-induced JAK/STAT signaling were determined by flow cytometry, and expression of SOCS-3 was assessed by quantitative polymerase chain reaction. The role of endogenous SOCS-3 was examined in cartilage explants and chondrocytes from mice with conditional deletion of Socs3 driven by the Col2a1 promoter in vitro ( Socs3
Δ/Δcol2 ) and from mice during CD4+ T cell-dependent inflammatory monarthritis. Bone erosions in the murine joints were analyzed by micro-computed tomography. Results On chondrocytes from WT mice, gp130 and the oncostatin M (OSM) receptor were strongly expressed, whereas the transmembrane interleukin-6 (IL-6) receptor was expressed at much lower levels. Compared to other gp130 cytokines, OSM was the most potent activator of the JAK/STAT pathway and of SOCS-3 induction. Treatment of Socs3Δ/Δcol2 mouse cartilage explants and chondrocytes with gp130 cytokines prolonged JAK/STAT signaling, enhanced cartilage degradation, increased the expression of Adamts4, Adamts5, and RANKL, and elevated the production of IL-6, granulocyte colony-stimulating factor, CXCL1, and CCL2. Socs3Δ/Δcol2 mice developed exacerbated inflammation and joint damage in response to gp130 cytokine injections, and these histopathologic features were also observed in mice with inflammatory monarthritis. Conclusion The results of this study highlight a key role for SOCS-3 in regulating chondrocyte responses during inflammatory arthritis. Within the gp130 cytokine family, OSM is a potent stimulus of chondrocyte responses, while IL-6 probably signals via trans-signaling. The gp130 cytokine-driven production of RANKL in chondrocytes may link chondrocyte activation and bone remodeling during inflammatory arthritis. Thus, these findings suggest that the inhibition of OSM might reduce the development and severity of structural joint damage during inflammatory arthritis. [ABSTRACT FROM AUTHOR]- Published
- 2014
- Full Text
- View/download PDF
6. Validation of de-identified record linkage to ascertain hospital admissions in a cohort study.
- Author
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Beauchamp, Alison, Tonkin, Andrew M., Kelsall, Helen, Sundararajan, Vijaya, English, Dallas R., Sundaresan, Lalitha, Wolfe, Rory, Turrell, Gavin, Giles, Graham G., and Peeters, Anna
- Subjects
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COHORT analysis , *HOSPITAL admission & discharge , *MEDICARE , *MEDICAL records - Abstract
Background: Cohort studies can provide valuable evidence of cause and effect relationships but are subject to loss of participants over time, limiting the validity of findings. Computerised record linkage offers a passive and ongoing method of obtaining health outcomes from existing routinely collected data sources. However, the quality of record linkage is reliant upon the availability and accuracy of common identifying variables. We sought to develop and validate a method for linking a cohort study to a state-wide hospital admissions dataset with limited availability of unique identifying variables. Methods: A sample of 2000 participants from a cohort study (n = 41 514) was linked to a state-wide hospitalisations dataset in Victoria, Australia using the national health insurance (Medicare) number and demographic data as identifying variables. Availability of the health insurance number was limited in both datasets; therefore linkage was undertaken both with and without use of this number and agreement tested between both algorithms. Sensitivity was calculated for a sub-sample of 101 participants with a hospital admission confirmed by medical record review. Results: Of the 2000 study participants, 85% were found to have a record in the hospitalisations dataset when the national health insurance number and sex were used as linkage variables and 92% when demographic details only were used. When agreement between the two methods was tested the disagreement fraction was 9%, mainly due to "false positive" links when demographic details only were used. A final algorithm that used multiple combinations of identifying variables resulted in a match proportion of 87%. Sensitivity of this final linkage was 95%. Conclusions: High quality record linkage of cohort data with a hospitalisations dataset that has limited identifiers can be achieved using combinations of a national health insurance number and demographic data as identifying variables. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
7. Spawning behaviour of the endangered Macquarie Perch Macquaria australasica in an upland Australian river.
- Author
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Tonkin, Zeb, Lyon, Jarod, and Pickworth, Andrew
- Subjects
- *
MACQUARIE perch , *FISH habitats , *FRESHWATER fishes , *RESTORATION ecology , *HABITATS , *SPAWNING - Abstract
The article presents a study on the spawning behaviour and habitat of the endangered Macquarie Perch or Macquaria australasica in Lake Darthmouth, Victoria. The Macquarie Perch is a freshwater fish which suffered a decline in distribution and abundance and regarded as endangered due to habitat degradation. The study has provided information on the spawning behaviour and habitat use of Macquarie Perch with restoration efforts on the protection of spawning fish and their habitat.
- Published
- 2010
- Full Text
- View/download PDF
8. Mind the Gap: Mismatches Between Clinicians and Patients in Heart Failure Medication Management.
- Author
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Chin KL, Skiba M, Reid CM, Tonkin A, Hopper I, Mariani JA, and Liew D
- Subjects
- Aged, Cardiovascular Agents adverse effects, Cross-Sectional Studies, Drug Prescriptions, Drug Therapy, Combination, Female, Guideline Adherence, Health Care Surveys, Heart Failure diagnosis, Heart Failure physiopathology, Humans, Male, Middle Aged, Patient Education as Topic, Practice Guidelines as Topic, Victoria, Attitude of Health Personnel, Cardiovascular Agents administration & dosage, Health Knowledge, Attitudes, Practice, Heart Failure drug therapy, Medication Adherence, Medication Therapy Management standards, Practice Patterns, Physicians' standards, Professional Practice Gaps standards
- Abstract
Purpose: Previous studies on the 'treatment gap' in patients with heart failure (HF) have focused either on prescribing or patients' adherence to prescribed treatment. This study sought to determine whether or not recent initiatives to close the gap have also minimised any mismatches between physicians' expectation of their patients' medications, medications in the patients' possession and their actual medication use., Methods: A cross-sectional observational survey was conducted from December 2015 to June 2016 in The Alfred Hospital HF clinic in Melbourne, Australia. Patients were invited to participate if they had chronic HF (NYHA class II to IV), were aged ≥ 60 years, had no history of HF related hospitalisation within the past 6 months and were prescribed at least two HF medications., Results: Of 123 eligible patients, 102 were recruited into the study. Beta-blockers, mineralocorticoid receptor antagonists, loop diuretics and statins were associated with the highest rates of mismatches of drugs and doses, ranging from 10 to 17%. Discrepancy of total daily doses was the most common type of mismatch. Overall, only 23.5% of the patients were taking the right drugs at the right doses as expected by their cardiologists/HF specialists., Conclusions: Despite improved prescribers' adherence to guideline-directed medical therapy, there remain considerable mismatches between prescribers' expectation of patients' HF medications, medications in patients' possession and their actual medication use. Initiatives to improve this situation are urgently needed.
- Published
- 2018
- Full Text
- View/download PDF
9. Does Statin Benefits Patients with Heart Failure Undergoing Percutaneous Coronary Intervention? Findings from the Melbourne Interventional Group Registry.
- Author
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Chin KL, Wolfe R, Reid CM, Tonkin A, Hopper I, Brennan A, Andrianopoulos N, Duffy SJ, Clark D, Ajani A, and Liew D
- Subjects
- Aged, Coronary Artery Disease diagnosis, Coronary Artery Disease mortality, Coronary Artery Disease physiopathology, Female, Heart Failure diagnosis, Heart Failure mortality, Heart Failure physiopathology, Humans, Hydroxymethylglutaryl-CoA Reductase Inhibitors adverse effects, Male, Myocardial Infarction etiology, Patient Readmission, Registries, Risk Factors, Time Factors, Treatment Outcome, Victoria, Coronary Artery Disease therapy, Heart Failure therapy, Hydroxymethylglutaryl-CoA Reductase Inhibitors therapeutic use, Percutaneous Coronary Intervention adverse effects, Percutaneous Coronary Intervention mortality
- Abstract
Purpose: The effectiveness of statins in improving clinical outcomes among patients with heart failure (HF) undergoing percutaneous coronary intervention (PCI) is unclear. We examined the association between use of statins and clinical outcomes in patients with HF included in the Melbourne Interventional Group registry., Methods: Patients were followed from 30 days to 1 year post-PCI for a primary composite outcome of all-cause mortality and hospitalisation for cardiovascular (CV) causes. Secondary outcomes included major adverse cardiac events (MACE, a composite of all-cause mortality, myocardial infarction and target vessel revascularisation) and hospitalisation for CV causes. Outcomes were compared between statin-treated and non-statin-treated patients (at 30 days post-PCI) using propensity scores to balance for risk factors., Results: Among 991 patients included in the inverse probability-weighted Cox model, statin use had no significant effect on the primary composite outcome [adjusted hazard ratio (aHR), 1.03; 95% confidence interval (CI), 0.68 to 1.56; p = 0.89], nor MACE (aHR, 0.99; 95% CI, 0.54 to 1.84; p = 0.99) or hospitalisation for CV causes (HR, 1.13; 95% CI, 0.74 to 1.72; p = 0.57)., Conclusions: Our results suggest that statin therapy may confer no significant benefits in patients with HF undergoing PCI. However, prospective randomised controlled trials are needed to provide more definitive answers.
- Published
- 2018
- Full Text
- View/download PDF
10. Outdoor air pollution as a trigger for out-of-hospital cardiac arrests.
- Author
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Dennekamp M, Akram M, Abramson MJ, Tonkin A, Sim MR, Fridman M, and Erbas B
- Subjects
- Adult, Age Factors, Aged, Aged, 80 and over, Air Pollution analysis, Air Pollution statistics & numerical data, Carbon Monoxide adverse effects, Confidence Intervals, Female, Heart Arrest epidemiology, Humans, Logistic Models, Male, Middle Aged, Nitrogen Dioxide adverse effects, Ozone adverse effects, Particulate Matter analysis, Poisson Distribution, Proportional Hazards Models, Registries, Risk Factors, Sex Factors, Sulfur Dioxide adverse effects, Victoria epidemiology, Air Pollution adverse effects, Heart Arrest etiology, Particulate Matter adverse effects
- Abstract
Background: Epidemiologic studies have reported associations between fine particulate air pollution and cardiovascular mortality or hospitalization for cardiac events. However the evidence regarding the association between air pollution and acute cardiac events, such as out-of-hospital cardiac arrest, is inconsistent., Methods: We investigated the association between particulate matter (PM) air pollution and out-of-hospital cardiac arrest using a case-crossover study of adults (age, 35+ years) in Melbourne, Australia. We included 8434 cases identified through the Victorian Cardiac Arrest Registry from 2003 through 2006. We excluded arrests with an obvious preceding noncardiac event such as trauma, poisoning, or drowning, leaving only those events that were presumed to have cardiac etiology. Air pollution concentrations obtained from a central monitoring site were used for day of the arrest and for lag 1, lag 2, and lag 3, including the average lag 0-1., Results: An interquartile range increase of 4.26 microg/m3 in PM2.5 over 2 days (lag 0-1) was associated with an increase in risk for an out-of-hospital cardiac arrest of 3.6% (95% confidence interval = 1.3% to 6.0%). PM10 and carbon monoxide also showed associations, but not as strong as for PM2.5. Longer lag periods did not show such strong relationships. There was no association of these cardiac events with ozone, sulfur dioxide, or nitrogen dioxide in any lag period. Individuals age 65-74 years old were most susceptible to PM2.5 exposure, while those 75 years and older had the lowest risk., Conclusion: These findings support an association between daily average PM2.5 concentrations and an increased risk of out-of-hospital cardiac arrests.
- Published
- 2010
- Full Text
- View/download PDF
11. Radiofrequency catheter ablation of tachyarrhythmias--adult and paediatric experience.
- Author
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Kertes P, Kalman J, Edis B, Chen JM, Byrgiotis S, Kelly P, Tonkin A, and Wilkinson J
- Subjects
- Adolescent, Adult, Aged, Child, Female, Follow-Up Studies, Humans, Male, Middle Aged, Tachycardia, Supraventricular surgery, Victoria, Catheter Ablation, Tachycardia surgery
- Abstract
Background and Aims: Until recently, curative therapy for supraventricular tachycardia (SVT) was possible only with map-guided cardiac surgery. The ability to ablate permanently the reentrant circuit responsible for tachycardia using radiofrequency electrical current (RF) delivered through a catheter has now allowed cure of SVT by non-surgical means. We present our initial experience with this technique in both adult and paediatric patients., Methods: In 53 patients of median age 32 years, 56 radiofrequency catheter ablation procedures were performed for control of tachyarrhythmias. Fourteen patients were aged 18 years or less. Indications for RF ablation were SVT due to an accessory pathway (n = 27), SVT due to atrioventricular junctional reentry (AVJRT) (n = 22), incessant SVT (n = 2), ventricular tachycardia (n = 2), and uncontrolled atrial fibrillation (n = 3). General anaesthesia was used in 88% of procedures. Ablation was preceded by electrophysiological testing to confirm tachycardia mechanism in all cases., Results: The ablation procedure was completely successful in 49/56 cases (87.5%) and partially successful in another two cases. Only five procedures (9%) failed. Median procedure time was two hours, median fluoroscopy time was 24 min, and the median number of RF applications was four. There were no major differences in results comparing adult and paediatric patients. A transient ulnar nerve palsy was the only major complication observed. After a follow-up of one to 15 months, tachycardia has recurred in two patients (4%). Of the total 53 patients, 90.5% are currently asymptomatic and off all cardiac drug therapy. RF catheter ablation appears to be an effective, curative, and relatively safe alternative to long term drug therapy in the management of troublesome SVT.
- Published
- 1993
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