Medicine, Dentistry & Health Sciences Collected Works - Research Publications
Now showing items 1-12 of 362
Antibiotic prescribing in neonatal sepsis: an Australian nationwide survey.
Objective: To evaluate quality and variation in antibiotic prescribing for neonatal sepsis. Design: We analysed prescribing in hospitalised neonates using the National Antimicrobial Prescribing Survey in Australian neonates from 1 January 2014 to 31 December 2018. Setting: Data from antibiotic point prevalence surveys performed in hospitals, ranging from rural hospitals to tertiary paediatric and maternity hospitals within Australia. Patients: Admitted neonates <28 days of age from participating hospitals. Main outcome measures: Variation and appropriateness in prescribing for neonatal sepsis and variation in dosing for gentamicin and benzylpenicillin across hospitals. Results: A total of 415 prescriptions among 214 neonates from 39 different hospitals were included. The majority of prescriptions (342, 82.4%) were for neonates <7 days of age. The most commonly prescribed antibiotics were gentamicin and benzylpenicillin, with 323 (77.8%) prescriptions. Dosing variability was substantial, with doses ranging from 2 to 8 mg/kg for gentamicin (median 5 mg/kg, IQR 4-5) and from 45 to 72 mg/kg for benzylpenicillin (median 60 mg/kg, IQR 50-60), although only 13 (3.2%) and 19 (4.6%) prescriptions were locally assessed as inappropriate or non-compliant with guidelines, respectively. At time of audit, 22% of antibiotics had been given for more than 48 hours and 9% more than 72 hours, although microbiologically confirmed infection was documented in only nine (4.2%) neonates. Conclusions: Prescribing for neonatal sepsis was dominated by use of benzylpenicillin and gentamicin with substantial variation in dosing. A small minority had culture-confirmed infection. Efforts to standardise antibiotic dosing and duration for suspected neonatal sepsis are recommended.
Rapid Microscopy and Use of Vital Dyes: Potential to Determine Viability of Cryptococcus neoformans in the Clinical Laboratory
(PUBLIC LIBRARY SCIENCE, 2015-01-27)
BACKGROUND: Cryptococcus neoformans is the commonest cause of fungal meningitis, with a substantial mortality despite appropriate therapy. Quantitative culture of cryptococci in cerebrospinal fluid (CSF) during antifungal therapy is of prognostic value and has therapeutic implications, but is slow and not practicable in many resource-poor countries. METHODS: We piloted two rapid techniques for quantifying viable cryptococci using mixtures of live and heat-killed cryptococci cultured in vitro: (i) quantitative microscopy with exclusion staining using trypan blue dye, and (ii) flow cytometry, using the fluorescent dye 2'-7'-Bis-(2-carboxyethyl)-5-(6)-carboxyfluorescein, acetoxymethyl ester (BCECF-AM). Results were compared with standard quantitative cryptococcal cultures. Quantitative microscopy was also performed on cerebrospinal fluid (CSF) samples. RESULTS: Both microscopy and flow cytometry distinguished between viable and non-viable cryptococci. Cell counting (on log scale) by microscopy and by quantitative culture were significantly linearly associated (p<0.0001) and Bland-Altman analysis showed a high level of agreement. Proportions of viable cells (on logit scale), as detected by flow cytometry were significantly linearly associated with proportions detected by microscopy (p<0.0001) and Bland-Altman analysis showed a high level of agreement. CONCLUSIONS: Direct microscopic examination of trypan blue-stained cryptococci and flow-cytometric assessment of BCECF-AM-stained cryptococci were in good agreement with quantitative cultures. These are promising strategies for rapid determination of the viability of cryptococci, and should be investigated in clinical practice.
Parechovirus Genotype 3 Outbreak among Infants, New South Wales, Australia, 2013-2014
(CENTERS DISEASE CONTROL, 2015-07-01)
From October 2013 through February 2014, human parechovirus genotype 3 infection was identified in 183 infants in New South Wales, Australia. Of those infants, 57% were male and 95% required hospitalization. Common signs and symptoms were fever >38°C (86%), irritability (80%), tachycardia (68%), and rash (62%). Compared with affected infants in the Northern Hemisphere, infants in New South Wales were slightly older, both sexes were affected more equally, and rash occurred with considerably higher frequency. The New South Wales syndromic surveillance system, which uses near real-time emergency department and ambulance data, was useful for monitoring the outbreak. An alert distributed to clinicians reduced unnecessary hospitalization for patients with suspected sepsis.
PPAR gamma is reduced in the airways of non-CF bronchiectasis subjects and is inversely correlated with the presence of Pseudomonas aeruginosa
(PUBLIC LIBRARY SCIENCE, 2018-08-16)
BACKGROUND: Chronic airway inflammation in conditions such as cystic fibrosis (CF) and non-CF bronchiectasis is characterised by a predominant neutrophilic inflammatory response, commonly due to the presence of pathogenic bacteria such as Pseudomonas aeruginosa. We hypothesised that down-regulation of the anti-inflammatory nuclear transcription regulator peroxisome proliferator-activated receptor gamma (PPARγ in non-CF bronchiectasis subjects may explain why this exuberant neutrophilic inflammation is able to persist unchecked in the inflamed airway. METHODS: PPARγ gene expression was assessed in bronchoalveolar lavage fluid (BAL) of 35 macrolide naïve non-CF bronchiectasis subjects and compared with that in 20 healthy controls. Human RNA was extracted from pelleted BAL and PPARγ expression was determined by reverse-transcription quantitative PCR. Bacterial DNA was extracted from paired induced sputum and total bacterial load was determined by 16S rRNA qPCR. Quantification of individual bacterial species was achieved by qPCR. RESULTS: PPARγ expression was lower in subjects with non-CF bronchiectasis compared with healthy control subjects (control: 1.00, IQR 0.55-1.44, n = 20 vs. Bronchiectasis: 0.49, IQR 0.12-0.89; n = 35; p<0.001, Mann-Whitney U test). This lower PPARγ expression correlated negatively with Pseudomonas aeruginosa (r = -0.53, n = 31; p = 0.002). No significant association was seen between PPARγ and total bacterial levels or levels Haemophilus influenzae. CONCLUSION: PPARγ is expressed in low levels in the airways of non-CF bronchiectasis subjects, despite an aggressive inflammatory response. This low level PPARγ expression is particularly associated with the presence of high levels of P. aeruginosa, and may represent an intrinsic link with this bacterial pathogen.
Link-me: Protocol for a randomised controlled trial of a systematic approach to stepped mental health care in primary care
(ELSEVIER SCIENCE INC, 2019-03-01)
Primary care in Australia is undergoing significant reform, with a particular focus on cost-effective tailoring of mental health care to individual needs. Link-me is testing whether a patient-completed Decision Support Tool (DST), which predicts future severity of depression and anxiety symptoms and triages individuals into care accordingly, is clinically effective and cost-effective relative to usual care. The trial is set in general practices, with English-speaking patients invited to complete eligibility screening in their general practitioner's waiting room. Eligible and consenting patients will then complete the DST assessment and are randomised and stratified according to predicted symptom severity. Participants allocated to the intervention arm will receive feedback on DST responses, select treatment priorities, assess motivation to change, and receive a severity-matched treatment recommendation (information about and links to low intensity services for those with mild symptoms, or assistance from a specially trained health professional (care navigator) for those with severe symptoms). All patients allocated to the comparison arm will receive usual GP care plus attention control. Primary (psychological distress) and secondary (depression, anxiety, quality of life, days out of role) outcomes will be assessed at 6 and 12 months. Differences in outcome means between trial arms both across and within symptom severity group will be examined using intention-to-treat analyses. Within trial and modelled economic evaluations will be conducted to determine the value for money of credentials of Link-me. Findings will be reported to the Federal Government to inform how mental health services across Australia are funded and delivered in the future.
The node-weighted Steiner tree approach to identify elements of cancer-related signaling pathways
BACKGROUND: Cancer constitutes a momentous health burden in our society. Critical information on cancer may be hidden in its signaling pathways. However, even though a large amount of money has been spent on cancer research, some critical information on cancer-related signaling pathways still remains elusive. Hence, new works towards a complete understanding of cancer-related signaling pathways will greatly benefit the prevention, diagnosis, and treatment of cancer. RESULTS: We propose the node-weighted Steiner tree approach to identify important elements of cancer-related signaling pathways at the level of proteins. This new approach has advantages over previous approaches since it is fast in processing large protein-protein interaction networks. We apply this new approach to identify important elements of two well-known cancer-related signaling pathways: PI3K/Akt and MAPK. First, we generate a node-weighted protein-protein interaction network using protein and signaling pathway data. Second, we modify and use two preprocessing techniques and a state-of-the-art Steiner tree algorithm to identify a subnetwork in the generated network. Third, we propose two new metrics to select important elements from this subnetwork. On a commonly used personal computer, this new approach takes less than 2 s to identify the important elements of PI3K/Akt and MAPK signaling pathways in a large node-weighted protein-protein interaction network with 16,843 vertices and 1,736,922 edges. We further analyze and demonstrate the significance of these identified elements to cancer signal transduction by exploring previously reported experimental evidences. CONCLUSIONS: Our node-weighted Steiner tree approach is shown to be both fast and effective to identify important elements of cancer-related signaling pathways. Furthermore, it may provide new perspectives into the identification of signaling pathways for other human diseases.
Pharmacogenetic stimulation of neuronal activity increases myelination in an axon-specific manner
(NATURE PUBLISHING GROUP, 2018-01-22)
Mounting evidence suggests that neuronal activity influences myelination, potentially allowing for experience-driven modulation of neural circuitry. The degree to which neuronal activity is capable of regulating myelination at the individual axon level is unclear. Here we demonstrate that stimulation of somatosensory axons in the mouse brain increases proliferation and differentiation of oligodendrocyte progenitor cells (OPCs) within the underlying white matter. Stimulated axons display an increased probability of being myelinated compared to neighboring non-stimulated axons, in addition to being ensheathed with thicker myelin. Conversely, attenuating neuronal firing reduces axonal myelination in a selective activity-dependent manner. Our findings reveal that the process of selecting axons for myelination is strongly influenced by the relative activity of individual axons within a population. These observed cellular changes are consistent with the emerging concept that adaptive myelination is a key mechanism for the fine-tuning of neuronal circuitry in the mammalian CNS.
The Efficacy and Harms of Pharmacological Interventions for Aggression After Traumatic Brain Injury-Systematic Review
(FRONTIERS MEDIA SA, 2019-11-29)
Background: Aggression is a commonly reported problem following traumatic brain injury (TBI). It may present as verbal insults or outbursts, physical assaults, and/or property destruction. Aggressive behavior can fracture relationships and impede participation in treatment as well as a broad range of vocational and social activities, thereby reducing the individual's quality of life. Pharmacological intervention is frequently used to control aggression following TBI. The aim of this systematic review was to critically evaluate the evidence regarding efficacy of pharmacological interventions for aggression following TBI in adults. Methods: We reviewed studies in English, available before December 2018. MEDLINE, PubMed, CINAHL, EMBASE, PsycINFO, and CENTRAL databases were searched, with additional searching of key journals, clinical trials registries, and international drug regulators. The primary outcomes of interest were reduction in the severity of aggression and occurrence of harms. The secondary outcomes of interest were changes in quality of life, participation, psychological health (e.g., depression, anxiety), and cognitive function. Evidence quality was assessed using the Cochrane Risk of Bias tool and the Joanna Briggs Institute Critical Appraisal Instruments. Results: Ten studies were identified, including five randomized controlled trials (RCTs) and five case series. There were positive, albeit mixed, findings for the RCTs examining the use of amantadine in reducing irritability (n = 2) and aggression (n = 2). There were some positive findings favoring methylphenidate in reducing anger (n = 1). The evidence for propranolol was weak (n = 1). Individual analysis revealed differential drug response across individuals for both methylphenidate and propranolol. The less rigorous studies administered carbamazepine (n = 2), valproic acid (n = 1), quetiapine (n = 1), and sertraline (n = 1), and all reported reductions in aggression. However, given the lack of a control group, it is difficult to discern treatment effects from natural change over time. Conclusions: This review concludes that a recommendation for use of amantadine to treat aggression and irritability in adults following TBI is appropriate. However, there is a need for further well-designed, adequately powered and controlled studies of pharmacological interventions for aggression following TBI.
The hypoxia imaging agent Cu-II(atsm) is neuroprotective and improves motor and cognitive functions in multiple animal models of Parkinson's disease
(ROCKEFELLER UNIV PRESS, 2012-04-09)
Parkinson's disease (PD) is a progressive, chronic disease characterized by dyskinesia, rigidity, instability, and tremors. The disease is defined by the presence of Lewy bodies, which primarily consist of aggregated α-synuclein protein, and is accompanied by the loss of monoaminergic neurons. Current therapeutic strategies only give symptomatic relief of motor impairment and do not address the underlying neurodegeneration. Hence, we have identified Cu(II)(atsm) as a potential therapeutic for PD. Drug administration to four different animal models of PD resulted in improved motor and cognition function, rescued nigral cell loss, and improved dopamine metabolism. In vitro, this compound is able to inhibit the effects of peroxynitrite-driven toxicity, including the formation of nitrated α-synuclein oligomers. Our results show that Cu(II)(atsm) is effective in reversing parkinsonian defects in animal models and has the potential to be a successful treatment of PD.
Indigenous Health and Human Rights: A Reflection on Law and Culture
In Australia, Aboriginal and Torres Strait Islander peoples bear a greater burden of disease and have lower life expectancy than their non-Indigenous counterparts. These combined indicators are evidence of an entrenched health crisis in the Indigenous population that is linked to systemic disadvantage over many decades. In an effort to improve life expectancy and lessen the burden of disease, a number of strategies and national frameworks now embed a human rights-based approach to achieving health equality. This paper explores the application of human rights to Indigenous health and examines the inherent tensions that exist in engaging a system of law based on universal assumptions of the Enlightenment to advance Indigenous rights. What becomes apparent through this exploration is that the strategic approach of Indigenous peoples’ use of human rights, despite its genesis in a system of law that
The HSA21 gene EURL/C21ORF91 controls neurogenesis within the cerebral cortex and is implicated in the pathogenesis of Down Syndrome
(NATURE PUBLISHING GROUP, 2016-07-11)
Copy number variations to chromosome 21 (HSA21) cause intellectual disability and Down Syndrome, but our understanding of the HSA21 genetic factors which contribute to fetal brain development remains incomplete. Here, we focussed on the neurodevelopmental functions for EURL (also known as C21ORF91, Refseq Gene ID:54149), a protein-coding gene at the centromeric boundary of the Down Syndrome Critical Region (DSCR) of HSA21. We report that EURL is expressed during human and mouse cerebral cortex development, and we report that alterations to EURL mRNA levels within the human brain underlie Down Syndrome. Our gene perturbation studies in mice demonstrate that disruptions to Eurl impair progenitor proliferation and neuronal differentiation. Also, we find that disruptions to Eurl impair the long-term positioning and dendritic spine densities of cortical projection neurons. We provide evidence that EURL interacts with the coiled-coil domain-containing protein CCDC85B so as to modulate β-catenin levels in cells. Further, we utilised a fluorescent reporter (8xTOPFLASHd2EGFP) to demonstrate that disruptions to Eurl alter β-catenin signalling in vitro as well as in vivo. Together, these studies highlight EURL as an important new player in neuronal development that is likely to impact on the neuropathogenesis of HSA21-related disorders including Down Syndrome.
Embedding effective depression care: using theory for primary care organisational and systems change
BACKGROUND: Depression and related disorders represent a significant part of general practitioners (GPs) daily work. Implementing the evidence about what works for depression care into routine practice presents a challenge for researchers and service designers. The emerging consensus is that the transfer of efficacious interventions into routine practice is strongly linked to how well the interventions are based upon theory and take into account the contextual factors of the setting into which they are to be transferred. We set out to develop a conceptual framework to guide change and the implementation of best practice depression care in the primary care setting. METHODS: We used a mixed method, observational approach to gather data about routine depression care in a range of primary care settings via: audit of electronic health records; observation of routine clinical care; and structured, facilitated whole of organisation meetings. Audit data were summarised using simple descriptive statistics. Observational data were collected using field notes. Organisational meetings were audio taped and transcribed. All the data sets were grouped, by organisation, and considered as a whole case. Normalisation Process Theory (NPT) was identified as an analytical theory to guide the conceptual framework development. RESULTS: Five privately owned primary care organisations (general practices) and one community health centre took part over the course of 18 months. We successfully developed a conceptual framework for implementing an effective model of depression care based on the four constructs of NPT: coherence, which proposes that depression work requires the conceptualisation of boundaries of who is depressed and who is not depressed and techniques for dealing with diffuseness; cognitive participation, which proposes that depression work requires engagement with a shared set of techniques that deal with depression as a health problem; collective action, which proposes that agreement is reached about how care is organised; and reflexive monitoring, which proposes that depression work requires agreement about how depression work will be monitored at the patient and practice level. We describe how these constructs can be used to guide the design and implementation of effective depression care in a way that can take account of contextual differences. CONCLUSIONS: Ideas about what is required for an effective model and system of depression care in primary care need to be accompanied by theoretically informed frameworks that consider how these can be implemented. The conceptual framework we have presented can be used to guide organisational and system change to develop common language around each construct between policy makers, service users, professionals, and researchers. This shared understanding across groups is fundamental to the effective implementation of change in primary care for depression.