Medicine, Dentistry & Health Sciences Collected Works - Research Publications
Now showing items 1-12 of 914
Spatial patterns of genetic diversity among Australian alpine flora communities revealed by comparative phylogenomics
AIM: The alpine region of mainland Australia is one of the world's 187 biodiversity hotspots. Genetic analyses of Australian alpine fauna indicate high levels of endemism on fine spatial scales, unlike Northern Hemisphere alpine systems where shallow genetic differentiation is typically observed among populations. These discrepancies have been attributed to differences in elevation and influence from glacial activity, and point to a unique phylogeographic history affecting Australian alpine biodiversity. To test generality of these findings across Australian alpine biota, we assessed patterns of genetic structure across plant species. LOCATION: The Australian Alps, Victoria, eastern Australia. METHODS: We used an economical pooled genotypingâ byâ sequencing (GBS) approach to examine patterns of genetic diversity among seven widespread species including shrubs and forbs from 16 mountain summits in the Australian Alpine National Park. Patterns of genetic structure among summit populations for each species were inferred from an average of 2,778 independent SNP loci using Bayesian phylogenomic inference and clustering approaches. RESULTS: SNP results were consistent across species in identifying deep evolutionary splits among summit communities from the Northern and Central Victorian Alpine regions. These patterns of genetic structure are also consistent with those previously reported for invertebrate and mammal taxa. However, local genetic structure was less pronounced in the plants, supporting the notion that population connectivity tends to be higher in plant species. MAIN CONCLUSION: There is deep lineage diversification between the North and Central Victorian Alpine regions, reflecting a high level of endemism. These findings differ from those reported for alpine biodiversity from New South Wales and much of the Northern Hemisphere, and support the notion that genetic diversity is typically greatest in areas least affected by historical ice sheet formation. We discuss the implications of our findings in the context of conservation planning, and highlight the benefits of this rapid and costâ effective genome scan approach for characterizing evolutionary processes at multispecies and landscape scales.
Direct access colonoscopy: impact of intervention on time to colorectal cancer diagnosis and treatment in North West Tasmania
BACKGROUND: Direct access colonoscopy (DAC) allows general practitioners to refer directly for colonoscopy, without specialist review. Research suggests DAC reduces times to diagnosis and treatment of colorectal cancer. However, there is no information about outcomes of DAC in Australia. AIM: To determine if DAC in North West Tasmania expedited colorectal diagnosis and treatment. METHODS: Pre-post intervention study evaluating time from referral to diagnosis and definitive treatment. Patient demographic characteristics, referral, colonoscopy and treatment information was retrieved from hospital records. Timelines were investigated in standard referrals (SR), emergency department/inpatient referrals and DAC using survival analysis. RESULTS: Two hundred and six colorectal cancer cases were identified (117 SR, 26 DAC, 48 emergency department/inpatient and 15 unknown pathways). Median time to colonoscopy/diagnosis (DAC 6 weeks vs SR 7 weeks, P = 0.55) or definitive treatment (surgery/chemoradiation) (DAC 8 weeks vs SR 9 weeks, P = 0.81) was not significantly improved with DAC. Among SR only, time to diagnosis was 9 weeks pre-intervention versus 5 weeks post-intervention (P = 0.13), and time to treatment was 11 weeks pre-intervention versus 6 weeks post-intervention (P = 0.07). CONCLUSION: There was no statistically significant improvement in time to colorectal cancer diagnosis or treatment among patients referred through DAC compared to SR. There was a trend towards improved waiting times for SR concurrent with the introduction of the DAC pathway, indicating improvement of all referral processes. DAC may not be effective at expediting colorectal cancer diagnosis if it is not accompanied by strict referral guidelines. Larger evaluations of DAC are required in the Australian context.
Hearing and neurodevelopmental outcomes for children with asymptomatic congenital cytomegalovirus infection: A systematic review
INTRODUCTION: Congenital CMV is one of the commonest congenital infections and a recognised cause of sensorineural hearing loss and neurodevelopmental impairment. Ninety percent are clinically inapparent at birth but are reported to be at risk of developing such abnormalities throughout childhood, the extent of which requires further elucidation. METHODS: A systematic literature review was conducted using Medline and Embase databases, manual citation review, and personal libraries for articles reporting primary data on hearing and neurodevelopmental outcomes for children with asymptomatic congenital CMV. PROSPERO registration number CRD42015025407. RESULTS: Thirty-seven of 480 articles identified between 1969 and 2016 met the eligibility criteria. Twenty-nine of these contributed primary data on hearing outcomes and 20 on neurodevelopmental outcomes (12 of the 37 studies contributed data on both). Cumulative incidence of sensorineural hearing loss with follow-up to at least 5 years was 7% to 11%, which is more than healthy controls but less than children with symptomatic congenital CMV (34%-41%). The onset, course, and severity of hearing loss was variable with no reliable virological prognostic marker. In comparison to controls, children with asymptomatic congenital CMV did not perform worse than controls in neurodevelopmental assessments and performed better than children with symptomatic congenital CMV. CONCLUSIONS: Studies show children with asymptomatic congenital CMV are at increased risk of developing hearing loss but perform equally well on neurodevelopmental assessments when compared with healthy controls. There is no reliable virological marker to determine which infants will develop sequelae. Regular follow-up until school entry is supported by the literature.
Testing the niche-breadth-range-size hypothesis: habitat specialization vs. performance in Australian alpine daisies
Relatively common species within a clade are expected to perform well across a wider range of conditions than their rarer relatives, yet experimental tests of this "niche-breadth-range-size" hypothesis remain surprisingly scarce. Rarity may arise due to trade-offs between specialization and performance across a wide range of environments. Here we use common garden and reciprocal transplant experiments to test the niche-breadth-range-size hypothesis, focusing on four common and three rare endemic alpine daisies (Brachyscome spp.) from the Australian Alps. We used three experimental contexts: (1) alpine reciprocal seedling experiment, a test of seedling survival and growth in three alpine habitat types differing in environmental quality and species diversity; (2) warm environment common garden, a test of whether common daisy species have higher growth rates and phenotypic plasticity, assessed in a common garden in a warmer climate and run simultaneously with experiment 1; and (3) alpine reciprocal seed experiment, a test of seed germination capacity and viability in the same three alpine habitat types as in experiment 1. In the alpine reciprocal seedling experiment, survival of all species was highest in the open heathland habitat where overall plant diversity is high, suggesting a general, positive response to a relatively productive, low-stress environment. We found only partial support for higher survival of rare species in their habitats of origin. In the warm environment common garden, three common daisies exhibited greater growth and biomass than two rare species, but the other rare species performed as well as the common species. In the alpine reciprocal seed experiment, common daisies exhibited higher germination across most habitats, but rare species maintained a higher proportion of viable seed in all conditions, suggesting different life history strategies. These results indicate that some but not all rare, alpine endemics exhibit stress tolerance at the cost of reduced growth rates in low-stress environments compared to common species. Finally, these findings suggest the seed stage is important in the persistence of rare species, and they provide only weak support at the seedling stage for the niche-breadth-range-size hypothesis.
Study of the Huntington's disease IT-15 gene in different ethnic groups in Ecuador.
This study aims to establish the current state of the IT-15 (HTT) gene in different Ecuadorian ethnic groups and patients by determining CAG triplet repeats, compared with the ethnicity of individuals. A total of 412 individuals were studied using nested polymerase chain reaction and Sanger sequencing: 75 individuals were indigenous (Kichwas), 211 mestizos, and 65 Afro-Ecuadorians. We included 31 patients who were clinically diagnosed with Huntington's disease (HD) and relatives of the affected patients (n = 30). Moreover, we correlated the presence of HD in Ecuadorian patients with 46 genetic ancestry-informative insertion-deletion polymorphic markers. We found that 77.20% had <28 CAG repetitions, 18.80% had mutable alleles, 2.27% had incomplete penetrance, and 1.70% reflected >39 repetitions. The average of CAG repetitions was 24 ± 3 for indigenous people; 28 ± 2 for mestizos; and 24 ± 3.2 repetitions for the Afro-Ecuadorians. The ancestral component showed that the main ancestry corresponded to Native Americans (0.873) and European ascendants (0.145), Africans were less represented in the evaluated population (0.018). There was a significant difference between the number of CAG repeats in mestizos and indigenous people (P < .01), suggesting that the Ecuadorian mestizo population has a risk factor for the gene mutation.
Plasma Proteome Association and Catalytic Activity of Stealth Polymer-Grafted Iron Oxide Nanoparticles
(WILEY-V C H VERLAG GMBH, 2017-09-27)
Polyethylene glycol (PEG) is widely used as an antifouling and stealth polymer in surface engineering and nanomedicine. However, recent research has revealed adverse effects of bioaccumulation and immunogenicity following the administration of PEG, prompting this proteomic examination of the plasma protein coronae association with superparamagnetic iron oxide nanoparticles (IONPs) grafted with brushed PEG (bPEG) and an alternative, brushed phosphorylcholine (bPC). Using label-free quantitation by liquid chromatography tandem-mass spectrometry, this study determines protein abundances for the in vitro hard coronae of bare, bPC-, and bPEG-grafted IONPs in human plasma. This study also shows unique protein compositions in the plasma coronae of each IONP, including enrichment of coagulation factors and immunogenic complement proteins with bPEG, and enhanced binding of apolipoproteins with bPC. Functional analysis reveals that plasma protein coronae elevate the horseradish peroxidase-like activities of the bPC- and bPEG-IONPs by approximately twofold, an effect likely mediated by the diverse composition and physicochemical properties of the polymers as well as their associated plasma proteins. Taken together, these observations support the rational design of stealth polymers based on a quantitative understanding of the interplay between IONPs and the plasma proteome, and should prove beneficial for the development of materials for nanomedicine, biosensing, and catalysis.
Visual methods in health dialogues: A qualitative study of public health nurse practice in schools
AIMS: We aimed to explore how using visual methods might improve or complicate the dynamics of the health dialogue between public health nurses (PHNs) and school pupils. This was done from the perspective of PHNs, specifically examining how they understood their role and practice as a PHN and the application of visual methods in this practice. BACKGROUND: The health dialogue is a method used by PHNs in school nursing in Norway. In this practice, there can be communicative barriers between pupils and PHNs. Investigating how PHNs understand their professional practice can lead to ways of addressing these communicative barriers, which can affect pupil satisfaction and achievement of health-related behaviours in the school context. Specifically, the use of visual methods by PHNs may address these communicative barriers. DESIGN: The research design was qualitative, using focus groups combined with visual methods. METHODS: We conducted focus group interviews using a semi-structured discussion guide and visual methods with five groups of PHNs (n = 31) working in northern Norwegian school health services. The data were collected during January and February 2016. Discussions were audio recorded, transcribed and coded into themes and sub-themes using systematic text condensation and drawings were analysed using interpretive engagement, a method of visual analysis. FINDINGS: Drawings and focus group discussions showed that PHNs perceived their professional practice as primarily a relational praxis. The PHNs used a variety of visual methods as part of the health dialogue with school pupils. This active use of visualization worked to build and strengthen relations when words were inadequate and served to enhance the flexible and relational practice employed by the PHNs. CONCLUSIONS: PHNs used different kinds of visualization methods to establish relations with school pupils, especially when verbalization by the pupils was difficult. PHNs were aware of both the benefits and challenges of using visualization with school pupils in health education. We recommend the use of visual methods in schools because they are useful for PHNs, other health professionals and teachers working with children and young people in developing relations, particularly where verbal communication may be a challenge.
Clinical outcomes after local field conformal reirradiation of patients with retropharyngeal nodal metastasis
BACKGROUND: The purpose of this study was to present our experience with retropharyngeal node reirradiation using highly conformal radiotherapy (RT). METHODS: A retrospective screen of 2504 consecutively irradiated patients with head and neck malignancies between 2005 and 2015 identified 19 patients who underwent reirradiation for retropharyngeal node metastasis. Clinical and toxicity outcomes were assessed in these patients. RESULTS: Thirteen patients (68%) had squamous cell carcinoma. Eleven patients (58%) received conventionally fractionated intensity-modulated radiotherapy (IMRT) or proton therapy, and 8 patients (42%) received single-fractionated or hypofractionated stereotactic RT. Fourteen patients (74%) received chemotherapy. Median follow-up was 14.7 months. The 1-year local control, locoregional control, overall survival, and progression-free survival rates were 100%, 94%, 92%, and 92%, respectively. Three patients (16%) experienced acute grade 3 toxicity and occurred in those treated with IMRT. There was no late grade ≥3 toxicity. CONCLUSION: Retropharyngeal node reirradiation with conformal therapy is well tolerated and associated with excellent short-term disease control.
Role of art centres for Aboriginal Australians living with dementia in remote communities
OBJECTIVE: To explore the role art centres in remote communities play for Aboriginal and Torres Strait Islander Australians living with dementia. METHODS: A comprehensive literature search was undertaken, with no restrictions on articles regarding year of publication. RESULTS: Art programmes have been found to be of benefit to both people living with dementia and their carers, particularly when programmes are administered in environments that are culturally revered. Findings indicate remote art centres play a key role in maintaining traditions, culture and practices unique to Aboriginal and Torres Strait Islanders, but there is a gap in knowledge regarding how they cater for the needs of people with dementia. CONCLUSION: Addressing this gap will be helpful in remote areas where prevalence of dementia is up to five times that of non-Aboriginal people, and there are limited health and support services. Further research is required to explore strengths and gaps of current practices.
Filling the gaps and finding our way: family carers navigating the healthcare system to access physical health services for the people they care for.
AIMS AND OBJECTIVES: To elicit the perspectives of carers of people with mental illness regarding access to, and experience with, physical healthcare services for mental health consumers. BACKGROUND: People diagnosed with mental illness have increased risks of physical illness and earlier death, problems able to be addressed through better physical health services. Carers of people with mental illness play a significant role in the mental healthcare system yet research examining their views is lacking. DESIGN: Qualitative exploratory. METHODS: In-depth interviews were conducted with 13 mental health carers. They were asked to describe their views and experiences pertaining to the physical health and availability of physical health care for the people they care for. Data were analysed using the framework of Braun and Clarke. RESULTS: Analysis of carer responses identified two important themes: responsiveness and access, and a shortage of care coordination. Carers felt alienated from physical healthcare providers and were compelled to fill gaps in available care through persistence in ensuring access to physical healthcare services. CONCLUSIONS: The findings identify carers as key stakeholders in the physical health care for the people they care for. Their involvement in accessing and coordinating care provides vital perspective on health service capacity, which requires further consideration in the practice and research domains. RELEVANCE TO CLINICAL PRACTICE: Carers of people diagnosed with mental illness are crucial to the effective delivery of mental health services. Their perspectives must be central to their research agenda and contribute to the development of initiatives to improve clinical practice and promote improved physical health care.