Melbourne University Sport - Research Publications
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ItemInfrared modulation via near-room-temperature phase transitions of vanadium oxides & core–shell composites(Royal Society of Chemistry (RSC), 2023)Vanadium oxides (VOx) are highly promising materials for heat retardant coatings, enabled by their insulator-to-metal phase transition (IMT). Currently, this IMT typically occurs at 68 °C, well above room temperature. Here, we develop a dopant-free approach to lower the IMT temperature to ∼40 °C enabling near-room temperature infrared modulation, by simple, solution phase synthesis. This is achieved by both controlling the stoichiometry of the metal oxide and by using a SiO2 shell around the VOx particles, with the difference in thermal expansion coefficient between SiO2 and VOx inducing sufficient strain in the VOx to dramatically lower the IMT temperature. This approach enables the production of a functional solution of suspended VOx nanoparticles with near-room temperature IMT. The combination of near-room temperature IMT and solution phase nanoparticles dramatically increases the ease, scalability, and efficacy of VOx application.
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ItemThe epidemiology of in-hospital cardiac arrests in Australia and New Zealand(WILEY, 2016-10-01)BACKGROUND: The epidemiology of in-hospital cardiac arrests (IHCA) in Australia and New Zealand (ANZ) has not been systematically assessed. AIM: To conduct a systematic review of the frequency, characteristics and outcomes of adult IHCA in ANZ. METHODS: Medline search for studies published in 1964-2014 using MeSH terms 'arrest AND hospital AND Australia', 'arrest AND hospital AND New Zealand', 'inpatient AND arrest AND Australia' and 'inpatient AND arrest AND New Zealand'. RESULTS: We screened 934 studies, analysed 50 and included 30. Frequency of IHCA ranged from 1.31 to 6.11 per 1000 admissions in 4 population studies and 0.58 to 4.59 per 1000 in 16 cohort studies. The frequency was 4.11 versus 1.32 per 1000 admissions in hospitals with rapid response system (RRS) compared with those without (odds ratio: 0.32; 95% confidence interval 0.28-0.37; P < 0.001). On aggregate, the initial cardiac rhythm was ventricular tachycardia/fibrillation in 31.4% (range 19.0-48.8%) in 10 studies reporting such data. On aggregate, IHCA were witnessed in 80.2% cases (three studies) and monitored patients in 53.4% cases (four studies). Details of life support were poorly documented. On aggregate, return of spontaneous circulation occurred in 46.0% of patients. Overall, 74.6% (range 59.4-77.5%) died in-hospital but survival was higher among monitored or younger patients, in those with a shockable rhythm, or during working hours. CONCLUSION: IHCA are uncommon in ANZ and three quarters die in-hospital. However, their frequency varies markedly across institutions and may be affected by the presence of RRS. Where reported, the long-term outcomes survivors appear to have acceptable neurological outcomes.
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ItemAndrogen receptor antagonism accelerates disease onset in the SOD1(G93A) mouse model of amyotrophic lateral sclerosis(WILEY, 2019-07-01)BACKGROUND AND PURPOSE: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease typically more common in males, implicating androgens in progression of both patients and mouse models. Androgen effects are mediated by androgen receptor which is highly expressed in spinal motor neurons and skeletal muscles. To clarify the role of androgen receptors in ALS, we therefore examined the effect of androgen receptor antagonism in the SOD1G93A mouse model. EXPERIMENTAL APPROACH: The androgen receptor antagonist, flutamide, was administered to presymptomatic SOD1G93A mice as a slow-release subcutaneous implant (5 mg·day-1 ). Testosterone, flutamide, and metabolite levels were measured in blood and spinal cord tissue by LC-MS-MS. Effects on disease onset and progression were assessed using motor function tests, survival, muscle, and neuropathological analyses. KEY RESULTS: Flutamide was metabolised to 2-hydroxyflutamide achieving steady-state plasma levels across the study duration and reached the spinal cord at pharmacologically active concentrations. Flutamide treatment accelerated disease onset and locomotor dysfunction in male SOD1G93A mice, but not female mice, without affecting survival. Analysis of hindlimb muscles revealed exacerbation of myofibre atrophy in male SOD1G93A mice treated with flutamide, although motor neuron pathology was not affected. CONCLUSION AND IMPLICATIONS: The androgen receptor antagonist accelerated disease onset in male SOD1G93A mice, leading to exacerbated muscle pathology, consistent with a role of androgens in modulating disease severity, sexual dimorphism, and peripheral pathology in ALS. These results also demonstrate a key contribution of skeletal muscle pathology to disease onset, but not outcome, in this mouse model of ALS.
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ItemExploring germline recombination inNestin-Cretransgenic mice using floxed androgen receptor(WILEY, 2020-08-03)The Cre-loxP strategy for tissue selective gene deletion has become a widely employed tool in neuroscience research. The validity of these models is largely underpinned by the temporal and spatial selectivity of recombinase expression under the promoter of the Cre driver line. Ectopic Cre-recombinase expression gives rise to off-target effects which can confound results and is especially detrimental if this occurs in germline cells. The Nestin-Cre transgenic mouse is broadly used for selective gene deletion in neurons of the central and peripheral nervous systems. Here we have crossed this mouse with a floxed androgen receptor (AR) transgenic to generate double transgenic neuronal ARKO mice (ARflox ::NesCre) to study germline deletion in male and female transgenic breeders. In male ARflox ::NesCre breeders, a null AR allele was passed on to 86% of progeny regardless of the inheritance of the NesCre transgene. In female ARflox/wt ::NesCre breeders, a null AR allele was passed on to 100% of progeny where ARflox was expected to be transmitted. This surprisingly high incidence of germline recombination in the Nestin-Cre driver line warrants caution in devising suitable breeding strategies, consideration of accurate genotyping approaches and highlights the need for thorough characterization of tissue-specific gene deletion in this model.
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ItemEffect of Vitamin C, Hydrocortisone, and Thiamine vs Hydrocortisone Alone on Time Alive and Free of Vasopressor Support Among Patients With Septic Shock The VITAMINS Randomized Clinical Trial(AMER MEDICAL ASSOC, 2020-02-04)IMPORTANCE: It is unclear whether vitamin C, hydrocortisone, and thiamine are more effective than hydrocortisone alone in expediting resolution of septic shock. OBJECTIVE: To determine whether the combination of vitamin C, hydrocortisone, and thiamine, compared with hydrocortisone alone, improves the duration of time alive and free of vasopressor administration in patients with septic shock. DESIGN, SETTING, AND PARTICIPANTS: Multicenter, open-label, randomized clinical trial conducted in 10 intensive care units in Australia, New Zealand, and Brazil that recruited 216 patients fulfilling the Sepsis-3 definition of septic shock. The first patient was enrolled on May 8, 2018, and the last on July 9, 2019. The final date of follow-up was October 6, 2019. INTERVENTIONS: Patients were randomized to the intervention group (n = 109), consisting of intravenous vitamin C (1.5 g every 6 hours), hydrocortisone (50 mg every 6 hours), and thiamine (200 mg every 12 hours), or to the control group (n = 107), consisting of intravenous hydrocortisone (50 mg every 6 hours) alone until shock resolution or up to 10 days. MAIN OUTCOMES AND MEASURES: The primary trial outcome was duration of time alive and free of vasopressor administration up to day 7. Ten secondary outcomes were prespecified, including 90-day mortality. RESULTS: Among 216 patients who were randomized, 211 provided consent and completed the primary outcome measurement (mean age, 61.7 years [SD, 15.0]; 133 men [63%]). Time alive and vasopressor free up to day 7 was 122.1 hours (interquartile range [IQR], 76.3-145.4 hours) in the intervention group and 124.6 hours (IQR, 82.1-147.0 hours) in the control group; the median of all paired differences was -0.6 hours (95% CI, -8.3 to 7.2 hours; P = .83). Of 10 prespecified secondary outcomes, 9 showed no statistically significant difference. Ninety-day mortality was 30/105 (28.6%) in the intervention group and 25/102 (24.5%) in the control group (hazard ratio, 1.18; 95% CI, 0.69-2.00). No serious adverse events were reported. CONCLUSIONS AND RELEVANCE: In patients with septic shock, treatment with intravenous vitamin C, hydrocortisone, and thiamine, compared with intravenous hydrocortisone alone, did not significantly improve the duration of time alive and free of vasopressor administration over 7 days. The finding suggests that treatment with intravenous vitamin C, hydrocortisone, and thiamine does not lead to a more rapid resolution of septic shock compared with intravenous hydrocortisone alone. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03333278.
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ItemIntegrating acute stroke telemedicine consultations into specialists' usual practice: a qualitative analysis comparing the experience of Australia and the United Kingdom(BMC, 2017-11-21)BACKGROUND: Stroke telemedicine can reduce healthcare inequities by increasing access to specialists. Successful telemedicine networks require specialists adapting clinical practice to provide remote consultations. Variation in experiences of specialists between different countries is unknown. To support future implementation, we compared perceptions of Australian and United Kingdom specialists providing remote acute stroke consultations. METHODS: Specialist participants were identified using purposive sampling from two new services: Australia's Victorian Stroke Telemedicine Program (n = 6; 2010-13) and the United Kingdom's Cumbria and Lancashire telestroke network (n = 5; 2010-2012). Semi-structured interviews were conducted pre- and post-implementation, recorded and transcribed verbatim. Deductive thematic and content analysis (NVivo) was undertaken by two independent coders using Normalisation Process Theory to explore integration of telemedicine into practice. Agreement between coders was M = 91%, SD = 9 and weighted average κ = 0.70. RESULTS: Cross-cultural similarities and differences were found. In both countries, specialists described old and new consulting practices, the purpose and value of telemedicine systems, and concerns regarding confidence in the assessment and diagnostic skills of unknown colleagues requesting telemedicine support. Australian specialists discussed how remote consultations impacted on usual roles and suggested future improvements, while United Kingdom specialists discussed system governance, policy and procedures. CONCLUSION: Australian and United Kingdom specialists reported telemedicine required changes in work practice and development of new skills. Both groups described potential for improvements in stroke telemedicine systems with Australian specialists more focused on role change and the United Kingdom on system governance issues. Future research should examine if cross-cultural variation reflects different models of care and extends to other networks.
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ItemMeasuring performance on the Healthcare Access and Quality Index for 195 countries and territories and selected subnational locations: a systematic analysis from the Global Burden of Disease Study 2016(ELSEVIER SCIENCE INC, 2018-06-02)BACKGROUND: A key component of achieving universal health coverage is ensuring that all populations have access to quality health care. Examining where gains have occurred or progress has faltered across and within countries is crucial to guiding decisions and strategies for future improvement. We used the Global Burden of Diseases, Injuries, and Risk Factors Study 2016 (GBD 2016) to assess personal health-care access and quality with the Healthcare Access and Quality (HAQ) Index for 195 countries and territories, as well as subnational locations in seven countries, from 1990 to 2016. METHODS: Drawing from established methods and updated estimates from GBD 2016, we used 32 causes from which death should not occur in the presence of effective care to approximate personal health-care access and quality by location and over time. To better isolate potential effects of personal health-care access and quality from underlying risk factor patterns, we risk-standardised cause-specific deaths due to non-cancers by location-year, replacing the local joint exposure of environmental and behavioural risks with the global level of exposure. Supported by the expansion of cancer registry data in GBD 2016, we used mortality-to-incidence ratios for cancers instead of risk-standardised death rates to provide a stronger signal of the effects of personal health care and access on cancer survival. We transformed each cause to a scale of 0-100, with 0 as the first percentile (worst) observed between 1990 and 2016, and 100 as the 99th percentile (best); we set these thresholds at the country level, and then applied them to subnational locations. We applied a principal components analysis to construct the HAQ Index using all scaled cause values, providing an overall score of 0-100 of personal health-care access and quality by location over time. We then compared HAQ Index levels and trends by quintiles on the Socio-demographic Index (SDI), a summary measure of overall development. As derived from the broader GBD study and other data sources, we examined relationships between national HAQ Index scores and potential correlates of performance, such as total health spending per capita. FINDINGS: In 2016, HAQ Index performance spanned from a high of 97·1 (95% UI 95·8-98·1) in Iceland, followed by 96·6 (94·9-97·9) in Norway and 96·1 (94·5-97·3) in the Netherlands, to values as low as 18·6 (13·1-24·4) in the Central African Republic, 19·0 (14·3-23·7) in Somalia, and 23·4 (20·2-26·8) in Guinea-Bissau. The pace of progress achieved between 1990 and 2016 varied, with markedly faster improvements occurring between 2000 and 2016 for many countries in sub-Saharan Africa and southeast Asia, whereas several countries in Latin America and elsewhere saw progress stagnate after experiencing considerable advances in the HAQ Index between 1990 and 2000. Striking subnational disparities emerged in personal health-care access and quality, with China and India having particularly large gaps between locations with the highest and lowest scores in 2016. In China, performance ranged from 91·5 (89·1-93·6) in Beijing to 48·0 (43·4-53·2) in Tibet (a 43·5-point difference), while India saw a 30·8-point disparity, from 64·8 (59·6-68·8) in Goa to 34·0 (30·3-38·1) in Assam. Japan recorded the smallest range in subnational HAQ performance in 2016 (a 4·8-point difference), whereas differences between subnational locations with the highest and lowest HAQ Index values were more than two times as high for the USA and three times as high for England. State-level gaps in the HAQ Index in Mexico somewhat narrowed from 1990 to 2016 (from a 20·9-point to 17·0-point difference), whereas in Brazil, disparities slightly increased across states during this time (a 17·2-point to 20·4-point difference). Performance on the HAQ Index showed strong linkages to overall development, with high and high-middle SDI countries generally having higher scores and faster gains for non-communicable diseases. Nonetheless, countries across the development spectrum saw substantial gains in some key health service areas from 2000 to 2016, most notably vaccine-preventable diseases. Overall, national performance on the HAQ Index was positively associated with higher levels of total health spending per capita, as well as health systems inputs, but these relationships were quite heterogeneous, particularly among low-to-middle SDI countries. INTERPRETATION: GBD 2016 provides a more detailed understanding of past success and current challenges in improving personal health-care access and quality worldwide. Despite substantial gains since 2000, many low-SDI and middle-SDI countries face considerable challenges unless heightened policy action and investments focus on advancing access to and quality of health care across key health services, especially non-communicable diseases. Stagnating or minimal improvements experienced by several low-middle to high-middle SDI countries could reflect the complexities of re-orienting both primary and secondary health-care services beyond the more limited foci of the Millennium Development Goals. Alongside initiatives to strengthen public health programmes, the pursuit of universal health coverage hinges upon improving both access and quality worldwide, and thus requires adopting a more comprehensive view-and subsequent provision-of quality health care for all populations. FUNDING: Bill & Melinda Gates Foundation.
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ItemAedes aegypti has spatially structured and seasonally stable populations in Yogyakarta, Indonesia(BMC, 2015-12-01)BACKGROUND: Dengue fever, the most prevalent global arboviral disease, represents an important public health problem in Indonesia. Control of dengue relies on the control of its main vector, the mosquito Aedes aegypti, yet nothing is known about the population history and genetic structure of this insect in Indonesia. Our aim was to assess the spatio-temporal population genetic structure of Ae. aegypti in Yogyakarta, a densely populated region on Java with common dengue outbreaks. METHODS: We used multiple marker systems (microsatellites, nuclear and mitochondrial genome-wide single nucleotide polymorphisms generated via Restriction-site Associated DNA sequencing) to analyze 979 Ae. aegypti individuals collected from the Yogyakarta city and the surrounding hamlets during the wet season in 2011 and the following dry season in 2012. We employed individual- and group-based approaches for inferring genetic structure. RESULTS: We found that Ae. aegypti in Yogyakarta has spatially structured and seasonally stable populations. The spatial structuring was significant for the nuclear and mitochondrial markers, while the temporal structuring was non-significant. Nuclear markers identified three main genetic clusters, showing that hamlets have greater genetic isolation from each other and from the inner city sites. However, one hamlet experienced unrestricted mosquito interbreeding with the inner city, forming a single genetic cluster. Genetic distance was poorly correlated with the spatial distance among mosquito samples, suggesting stronger influence of human-assisted gene flow than active mosquito movement on spatial genetic structure. A star-shaped mitochondrial haplotype network and a significant R(2) test statistic (R(2) = 0.0187, P = 0.001) support the hypothesis that Ae. aegypti in Yogyakarta originated from a small or homogeneous source and has undergone a relatively recent demographic expansion. CONCLUSION: We report the first insights into the spatio-temporal genetic structure and the underlying processes in the dengue fever mosquito from Yogyakarta, Indonesia. Our results provide valuable information on the effectiveness of local control measures as well as guidelines for the implementation of novel biocontrol strategies such as release of Wolbachia-infected mosquitoes.
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ItemGlucocorticoids promote apoptosis of proinflammatory monocytes by inhibiting ERK activity(NATURE PUBLISHING GROUP, 2018-02-15)Glucocorticoids (GCs) are potent anti-inflammatory drugs whose mode of action is complex and still debatable. One likely cellular target of GCs are monocytes/macrophages. The role of GCs in monocyte survival is also debated. Although both granulocyte macrophage-colony stimulating factor (GM-CSF) and macrophage-CSF (M-CSF) are important regulators of macrophage lineage functions including their survival, the former is often associated with proinflammatory functions while the latter is important in lineage homeostasis. We report here that the GC, dexamethasone, induces apoptosis in GM-CSF-treated human monocytes while having no impact on M-CSF-induced monocyte survival. To understand how GCs, GM-CSF, and M-CSF are regulating monocyte survival and other functions during inflammation, we firstly examined the transcriptomic changes elicited by these three agents in human monocytes, either acting alone or in combination. Transcriptomic and Ingenuity pathway analyses found that dexamethasone differentially modulated dendritic cell maturation and TREM1 signaling pathways in GM-CSF-treated and M-CSF-treated monocytes, two pathways known to be regulated by ERK1/2 activity. These analyses led us to provide evidence that the GC inhibits ERK1/2 activity selectively in GM-CSF-treated monocytes to induce apoptosis. It is proposed that this inhibition of ERK1/2 activity leads to inactivation of p90 ribosomal-S6 kinase and Bad dephosphorylation leading in turn to enhanced caspase-3 activity and subsequent apoptosis. Furthermore, pharmacological inhibition of GC receptor activity restored the ERK1/2 signaling and prevented the GC-induced apoptosis in GM-CSF-treated monocytes. Increased tissue macrophage numbers, possibly from enhanced survival due to mediators such as GM-CSF, can correlate with inflammatory disease severity; also reduction in these numbers can correlate with the therapeutic benefit of a number of agents, including GCs. We propose that the ERK1/2 signaling pathway promotes survival of GM-CSF-treated proinflammatory monocytes, which can be selectively targeted by GCs as a novel mechanism to reduce local monocyte/macrophage numbers and hence inflammation.
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ItemRestrictive versus liberal fluid therapy in major abdominal surgery (RELIEF): rationale and design for a multicentre randomised trial(BMJ PUBLISHING GROUP, 2017-03-01)INTRODUCTION: The optimal intravenous fluid regimen for patients undergoing major abdominal surgery is unclear. However, results from many small studies suggest a restrictive regimen may lead to better outcomes. A large, definitive clinical trial evaluating perioperative fluid replacement in major abdominal surgery, therefore, is required. METHODS/ANALYSIS: We designed a pragmatic, multicentre, randomised, controlled trial (the RELIEF trial). A total of 3000 patients were enrolled in this study and randomly allocated to a restrictive or liberal fluid regimen in a 1:1 ratio, stratified by centre and planned critical care admission. The expected fluid volumes in the first 24 hour from the start of surgery in restrictive and liberal groups were ≤3.0 L and ≥5.4 L, respectively. Patient enrolment is complete, and follow-up for the primary end point is ongoing. The primary outcome is disability-free survival at 1 year after surgery, with disability defined as a persistent (at least 6 months) reduction in functional status using the 12-item version of the World Health Organisation Disability Assessment Schedule. ETHICS/DISSEMINATION: The RELIEF trial has been approved by the responsible ethics committees of all participating sites. Participant recruitment began in March 2013 and was completed in August 2016, and 1-year follow-up will conclude in August 2017. Publication of the results of the RELIEF trial is anticipated in early 2018. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier NCT01424150.