Medicine & Health

Publication Search Results

Now showing 1 - 10 of 130
  • (2018) Kaplan, Ruth
    Thesis
    Background: Public health organisations in Australia lag behind other sectors using client-facing smartphone applications (apps) to enhance service delivery. Patients are increasingly seeking smartphone-enabled health management resources. Mobile health (mHealth) systems incorporating apps may offer effective means of enabling patient-centred care. mHealth interventions can fail to translate into practice due to: design-reality gaps; real-world change outpacing research; or health service sociotechnical complexity. Pragmatic, participatory research methodologies may help meet these challenges. Tools such as the Consolidated Framework for Implementation Research (CFIR) offer structure around which investigators can build fit to context. Aim: Examine the feasibility and acceptability of a co-produced prototype mHealth intervention and model of care to manage gestational diabetes (GDM) focusing on barriers to translation into practice. Through Proof of Concept offer recommendations for future study. Methods: An mHealth system (SugaMama) was developed using lean, agile methodologies guided by Social Constructivist theory. It comprised a patient app (iPhone, Android); Bluetooth glucometer; and clinician web portal. Environmental analysis situated the study in a real-world context. The study was planned and evaluated by a Quality Improvement Collaborative (QIC) comprising patients, clinicians, health service managers and researchers. Mixed methods and an observational case study design were employed. Results: Sixteen GDM patients and seven clinicians trialled SugaMama over 44 days and found it to be technically feasible, acceptable and aligned with patient lifestyle. Technology functioned as intended. A sole critical issue related to planning for system downtime. Patients preferred supported self-management utilising SugaMama over standard care. Clinicians experienced increased control through viewing real-time patient data. For the next iteration more personalisation was requested by patients; clinicians sought improved medication management and integration with other systems. Conclusion: mHealth-enabled care is likely to support patient-clinician partnerships and extend health service reach. Utilisation of CFIR constructs and a QIC may support implementation. Critical barriers to translation into practice can arise despite an intervention being evidence-based; feasible; acceptable; and supported by sponsors, patients and clinicians in a target context.

  • (2019) Sarwat, Sidra
    Thesis
    Purpose: The tear film has a major role in dry eye disease, however its basic dynamics including spread, replenishment and turnover are not fully understood. This experimental study aimed to investigate the feasibility of using fluroscence of silicon quantum dots (Si-QDs) doped with transition metals such as scandium (Sc-Si-QDs), copper (Cu-Si-QDs) and zinc (Zn-Si-QDs) as a contrast agent to visualise and monitor the tear film. Methods: Sc-Si-QDs, Cu-Si-QDs and Zn-Si-QDs were synthesised in solution phase and characterised using photoluminescence (emission and excitation), absorbance and transient absorption measurements. The size distribution of Si-QDs was measured by TEM images. The fluorescence characteristics of these QDs were investigated when combined with TheraTears (a balanced electrolyte formula for dry eye therapy). An optical imaging system composed of a standard slit lamp biomicroscope combined with a high-resolution Zyla sCOMS camera, SOLIS software, optical mounts and emission filters (460 nm, 510 nm and 530 nm) was used for in vitro imaging of Si-QDs with TheraTears. The stability and intensity of fluorescence of the three different Si-QDs was measured. Cytotoxicity of the Si-QDs was assessed using cultured human corneal epithelial cells by trypan blue staining and MTT assays after 24 hours of exposure. Results: The average size of Si-QDs was 2.65 nm, which is desirable for visible photoluminescence. In vitro imaging of Sc-Si-QDs and Cu-Si-QDs indicated their stable and bright fluorescence with TheraTears. However, Sc-Si-QDs were significantly brighter compared to Cu-Si-QDs and Zn-Si-QDs, and the Zn-Si-QDs tended to clump in TheraTears. The fluorescence of the Si-QDs was detected even at a concentration of 0.01 ug/mL with a total volume of 10 uL. Cu-Si-QDs and Sc-Si-QDs were non-cytotoxic up to 16 ug/mL and Zn-Si-QDs at 8 ug/mL. Conclusions: The fluorescence of Cu-Si-QDs and Sc-Si-QDs was higher than Zn-Si-QDs and these Si-QDs were less toxic. Cu-Si-QDs and Sc-Si-QDs were safe over a wider concentration range than Zn-Si-QDs. Zn-Si-QDs and Cu-Si-QDs showed some aggregation at certain concentrations. Sc-Si-QDs are proposed as a better option for further in vivo imaging of the tear film.

  • (2019) Ogunlade, Samson
    Thesis
    This work focuses on the application of mathematical and statistical modeling to understand malaria infection and the corresponding immune responses in the human host in areas of high malaria exposure. In high malaria endemic areas, seasonal transmission occurs such that during the wet season, individuals are highly exposed to malaria infection but are not in the dry season. This work investigates how repeated exposures to malaria parasites contribute to parasite survival in the host during the dry season. By extending an existing mathematical model, exposure of individuals to P.falciparum infections over their lifetimes were simulated, with the models capturing the generation of partial immunity to these infections. Our model predicts that individuals with repeated exposure to malaria parasites acquire partial immunity with time and this partial immunity is not fully protective but elongates the duration of infection. Counterintuitively, the most protected individuals have the longest infections. Accordingly, I present the hypothesis that individuals with the most exposure and protection from malaria may be the ones responsible for carrying the parasites through the dry season. During the blood stage of malaria infection, when a shizont ruptures and releases merozoites, they must find and invade red blood cells (RBCs). However, it is known that the merozoites have a higher preference for infecting some cells (i.e. reticulocytes) compared to others. This work presents a probabilistic model of the invasion strategy a merozoite uses to find the “best” cell given the trade-off between longer search times and the benefit gained by the parasite. I observed that, different strategies of the parasites yield different susceptibilities of those parasites to killing. Overall, this work demonstrates the use of mathematical and statistical modeling concepts to analyse the strategies of malaria parasites survival which will help in contributing to the elimination of the malaria disease.

  • (2019) Eze, Thomas
    Thesis
    PURPOSE: Low vision rehabilitation improves the functional abilities of people with vision impairment but access to rehabilitation services remains low. This study aims to explore issues pertaining to the timing of low vision and rehabilitation services, from the patient’s perspective and translate patients’ preferences into practice. METHOD: A 2 phase qualitative study was designed. In the first phase, the views of people with visual impairment and who had accessed low vision services in Australia, were obtained through semi-structured telephone interviews. Contributions were audio-recorded, transcribed verbatim, and analysed thematically using NVivo software. This data was summarised. In Phase 2, focus groups were conducted, where the Phase 1 study was reported to low vision service providers and stakeholders with the purpose of developing an action plan to implement patient preferences. RESULTS: In Phase 1, 31 participants (median age 70 years, range 14-80, 18 females) were recruited. Participants had accessed two or more low vision rehabilitation services in all Australian states: low vision assessment, orientation and mobility, counselling, occupational therapy, peer support and library services. Participants judged the timing of their access to rehabilitation services as “good/ fine” and “useful” if it was early. Those who felt that they did not access rehabilitation services early enough held regrets and blamed it predominantly on lack of awareness of available services. Participants strongly preferred to receive information about low vision and rehabilitation services directly from their doctor at the time the diagnosis of their disease was made. In Phase 2, three focus groups with a total of 18 participants. Participants thought that eye care providers are not able to implement patient preferences in a busy clinic situation. All participants thought a consistent way of doing things across all stakeholders was required. CONCLUSION: Patients with visual impairment were most receptive to receiving information about rehabilitation services verbally, from their doctor, at the time of diagnosis of vision impairment. Low vision and eye care practitioners believed that patients preferences were not practicable in the ideal clinic consultations. A new approach that accommodates both patients and practitioner’s views was suggested.

  • (2017) Aggarwal, Gunjan
    Thesis
    Abstract Aims: Assessment of the differences in diagnostic performance and radiation dose between Adaptive Statistical Iterative Reconstruction (ASIR) and High Definition (HD) CT coronary angiography (CTCA) compared with Filtered Back Projection (FBP) and Standard Definition (SD) CTCA using invasive coronary angiography as a reference standard. Methods: Data from 2069 consecutive patients undergoing CTCA was collected over a period of 2 years. A total of 30 patients were separately enrolled if they had a significant stenosis and underwent invasive coronary angiogram within 3 months. All 30 patients were scanned in high definition and then had 5 reconstructions performed using SD0%ASIR, SD50%ASIR, SD70%ASIR, HD50%ASIR and HD70% ASIR. Results: Median and total (including CACS) angiographic radiation dose for 2069 patients was 2.1 mSv and 2.7 mSv respectively. Determinants of radiation dose on multivariate regression analysis were scan voltage, tube current, padding, scan length and heart rate. The mean difference in adjusted angiographic radiation dose using ANCOVA between the ASIR cohort (n=624, mean 2.2 mSv) and FBP (n=572, mean 2.29 mSv) was 0.09 mSv (P 0.0008). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and Area under the curve (AUC) values using Receiver Operator Characteristic (ROC) curves on an intention to diagnose analysis were highest for the reconstruction HD with 70% ASIR at 94%, 89%, 75%, 98% and 0.93 for a >50% obstructive stenosis threshold on a per artery basis; and 88%, 88%, 64%, 97% and 0.91 for a >70% stenosis on a per artery basis; 100%, 67%, 96%, 100% and 0.83 for a >50% stenosis on a per patient basis; and 95%, 67%, 87%, 86% and 0.81 for a >70% stenosis on a per patient basis. The greatest benefit for HD with 70% ASIR was in patient subgroups of CACS>200, BMI>25 and stented arteries with AUC values of 0.93, 0.89 and 0.83 respectively. Conclusions: ASIR resulted in a lower adjusted angiographic radiation dose than FBP although the reduction of 4.2% was less than that observed in other studies due to the tube current reduction with ASIR scans being smaller in our study. HD with 70% ASIR reconstruction demonstrated the most robust diagnostic performance with higher specificity, PPV and AUC values than all other reconstructions due to a lower false positive rate. These benefits were the most pronounced in patients with a CACS>200, BMI>25 and stented arteries.

  • (2018) De Rosa, Nicholas
    Thesis
    Introduction: Skin disease is common in immunosuppressed solid organ transplant recipients (SOTRs) and skin cancer, in particular, is a major cause of morbidity and mortality in these patients. This study aims to determine the rates and risk factors for skin cancer in Australian heart and lung transplant recipients (HLTRs). It also aims to examine the spectrum of skin diseases encountered in HLTRs and their effect on quality of life (QOL). Methods: Ninety-four participants were recruited from the Dermatology Outpatient Clinic at St. Vincent’s Hospital Sydney between March and December 2016. Retrospective skin cancer diagnoses were obtained from medical records and participants were also examined prospectively for malignant and non-malignant skin disease. A questionnaire and the Dermatology Life Quality Index were administered to all participants. The probabilities of developing non-melanoma skin cancer (NMSC), squamous cell carcinoma (SCC), and basal cell carcinoma (BCC) were estimated using Kaplan-Meier analysis. The association of risk factors with skin cancer development were examined using the Cox proportional hazards model. The association of examined variables with DLQI score were assessed using univariate and multivariate logistic regression analysis. Results: Retrospectively, there were 801 post-transplant skin cancers in 61% of participants. At 5 and 10 years post-transplantation the probabilities were 41% and 67% for developing NMSC, 27% and 53% for developing BCC, and 33% and 62% for developing SCC, respectively. A prospective dermatological diagnosis was made in 87% of the participants over the study period. Actinic keratosis was the most common diagnosis, affecting 53% of participants, followed by skin cancer in 44% and warts in 15% of participants. Other non-malignant skin diseases were less common. Risk factors significantly associated with skin cancer included older age at transplantation, history of pre-transplant skin cancer, and history of ≥5 post-transplant skin cancers. Fitzpatrick skin type 3-6 was associated with a decreased risk of NMSC. Skin disease had a negative effect on the QOL of a minority of HLTRs. The use of tacrolimus was associated with better QOL scores on multivariate analysis. Conclusion: Australian HLTRs have high rates of skin cancer that exceed the rates reported for other SOTRs.

  • (2017) Meinrath, Daniela
    Thesis
    Dizziness is a common health concern for older adults affecting up to 30% of people aged 65 years and over. Dizziness can be debilitating and significantly diminish quality of life and lead to depression, falls and functional disability. With population ageing, the burden of dizziness on health care systems will increase significantly. It is important, therefore, to better understand factors that predispose older people to this condition. The aims of this thesis were to identify key medical, physical and psychological factors associated with dizziness in two complementary cohorts: (1) 339 community-dwellers aged 75 years and older recruited through the electoral roll; (2) 313 people aged 50 years and older who experienced at least one significant dizziness episode in the past year. Participants completed questionnaires related to dizziness episodes, demographics, health and psychological well being. They also underwent assessments of sensorimotor function, vestibular function, dynamic balance, gait and cardiovascular health. Relationships between dizziness and these factors were then explored in both samples. In the general sample, the prevalence of dizziness was 23%. Within this group, participants who reported dizziness in the past year were more likely to also report back pain, motion sickness and fear of falling, than those who did not report any dizziness. Amongst the dizziness sufferers (cohort 2), a multivariate logistic regression analysis revealed that higher physiological fall risk, unilateral vestibular hypofunction and increased anxiety were significantly and independently associated with increased dizziness frequency. 28% of dizziness sufferers reported moderate to severe handicap. Cardiovascular medication use, increased anxiety, a positive test of Benign Paroxysmal Positional Vertigo, and higher physiological fall risk were identified as significant and independent predictors of higher dizziness handicap in multivariate logistic regression analysis. These findings indicate that dizziness is prevalent in older people, with many people with this condition experiencing significant handicap. Dizziness handicap was associated with both physical and psychological impairments. While it is difficult to establish causal relationships among all the associated factors, the significant associations uncovered provide insight into how dizziness affects older people, and information for possible strategies for treating this condition.

  • (2014) Arora, Manit
    Thesis
    Abstract â Burnout among Australian orthopaedic trainees and the factors associated with it Aim: To study burnout prevalence and associated factors among Australian orthopaedic trainees. Method: We conducted a nationwide cross-sectional observational study using a 32-question survey consisting of a self-developed item set of 10 questions and a 22-question validated instrument (Maslach Burnout Inventory â Human Services Survey) to assess burnout. The survey was emailed to 236 orthopaedic registrar members of the Australian Orthopaedic Association. Results: 51 trainees completed the survey, yielding a response rate of 22%. Burnout prevalence among orthopaedic trainees was high (52%) despite high career satisfaction (89%). 55% of trainees were dissatisfied with their work-life balance. Burned out trainees were more likely to be dissatisfied with their choice of orthopaedics as a career (p=0.004) and with their work-balance (p=0.021) compared with their non-burned out counterparts. Females were more likely to be burned out than males and non-married trainees more than married trainees, although these associations were not significant. There was no observed trend for burnout with relation to seniority in the training program. Discussion: Burnout prevalence among Australian orthopaedic trainees is high despite high career satisfaction. There may be a role for active interventions aimed at combating burnout and improving work-life balance among orthopaedic trainees. Abstract â Job satisfaction among Australian orthopaedic surgeons and the factors associated with it Introduction: High job satisfaction has positive outcomes for patients, health institutions and surgeons. There has been no research into job satisfaction primarily among Australian orthopaedic surgeons and its associated factors. The aim of this study was to assess job satisfaction and associated factors among Australian orthopaedic surgeons. Method: We conducted a nationwide survey using a 24-item questionnaire consisting of a self-developed item set of 14 questions and a 10-question modified version of Warr-Cook-Wall Job Satisfaction instrument to assess job satisfaction. The survey was emailed to 1393 orthopaedic surgeon members of the Australian Orthopaedic Association. Results: 217 surgeons completed the survey, yielding a response rate of 16%. 88% of responders were either very satisfied or moderately satisfied with their jobs. 20% of responders were dissatisfied with their hours of work and a further 15% of responders were dissatisfied with the level of recognition they get for good work. Surgeons with higher job satisfaction were less likely to feel that workload severely compromised their personal/family life (p<0.001), had better perceived self-health (p=0.04), and were less likely to have considered leaving orthopaedic surgery in the last year (p<0.001). Discussion: Australian orthopaedic surgeons are highly satisfied with their jobs. There may be a role for active interventions aimed at improving hours of work and work-life balance.

  • (2012) Kurniawan, Monica
    Thesis
    T cells are a type of white blood cell that are able to recognise and kill virally infected cells. T cells have receptors on their cell surface that facilitates the recognition of a viral peptide bound to the major histocompatibility complex (MHC) of an infected cell. An enormous diversity of T cell receptors (TCR) is needed to ensure the recognition of a wide variety of pathogens and immune control of infections. Therefore, many previous studies have attempted to understand the different factors that shape the T cell repertoire including the mechanisms that generate T cell receptor diversity. TCRs are generated by a somatic recombination process that involves somewhat random and imprecise mechanisms, including the selection and joining of up to three different types of gene segments (that is, the variable (V), diversity (D) and joining (J) genes), the addition of gene-templated palindromic nucleotides (P-nucleotides) at the gene ends, the deletion of nucleotides from the gene ends, and the addition of non-templated nucleotides (N-nucleotides). The prevalence and the contributions of each of these mechanisms to the generation of TCR diversity are generally well-studied and well-understood, with the exception of P-nucleotide addition. In this study, we examined more than 100,000 T cell receptor beta chain (TRB) sequences in order to investigate the prevalence of P-nucleotides in expressed TRB repertoires. These TCR sequences were obtained from various studies of T cell responses to infectious diseases in mice, rhesus macaques, and humans, as well as naive T cell repertoires. We implemented previously published approaches and developed novel bioinformatics algorithms to estimate the prevalence of palindromic nucleotides at either the intact V and J gene ends and to assess the likelihood that these nucleotides could have been contributed by the other genes or N-nucleotides involved in the V(D)J recombination rather than P-nucleotides arising from the hairpin splicing. Our results demonstrate a high prevalence of P-nucleotides (>5% of TRB sequences per species), even when attributing the palindromic nucleotides at the intact gene ends to other possible sources. Thus, P-nucleotide addition appears to make a non-trivial contribution to the generation of the TRB repertoire.

  • (2012) An, Siwei
    Thesis
    Background. Cardiovascular disease is a major cause of death and disability and treatment options are limited. Abnormal vascular smooth muscle cell (VSMC) proliferation is a key pathological feature in atherosclerosis, hypertension, and stenosis and restenosis. In order to design new and effective strategies to cure or prevent cardiovascular disease, it is important to better understand mechanisms of gene transcription, mRNA translation and related signaling pathways. Objective. The aims of this thesis were (i) to understand the function of YrdC in translational control in VSMC, and (ii) to dissect the signal transduction pathways underlying IL-1β-induced Egr-1 expression via MEK in VSMC. Results. In the first study, YrdC, which is upregulated after VSMC injury, was found to play a role in translational regulation, i.e. YrdC positively regulates protein synthesis. In the second study, the involvement of EGFR (tyrosine 845 phosphorylation) in IL-1β-induced Egr-1 expression was demonstrated in both VSMCs and mouse embryonic fibroblasts (MEF) and to mediate IL-1β-induced VSMC migration and proliferation. Conclusion. YrdC, once induced, may play a key role in promoting cell migration or proliferation by mediating protein synthesis in the reparative response to injury in VSMCs. IL-1β-induced Egr-1 expression is mediated through EGFR in VSMCs. These findings provide important insights on signaling responses to vascular cell injury.