ORCID Profile
0000-0002-4694-9479
Current Organisations
University of Western Australia
,
Flinders University
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Publisher: F1000 Research Ltd
Date: 15-01-2018
DOI: 10.15694/MEP.2018.0000011.1
Abstract: This article was migrated. The article was marked as recommended. Effective communication skills are a professional competency, yet are often overlooked during training. Providing immediate and constructive feedback is imperative to assist students in developing better communication skills. We sought to evaluate the educational value of using a university-developed application, Rapid Feedback, to provide feedback following students' oral presentations over two years.An online survey comprising of eight 5-point Likert scale items and one open-ended question was conducted in 114 (response rate = 86.5%) students. Students either strongly agreed or agreed that the feedback delivered was timely (98%), relevant (96%), high quality (90%), and specific to enhance their learning (87%). The feedback obtained has helped to identify strengths and weaknesses (87%). Students commented that feedback received will improve their communication skills (90%). The report was also shown to supplement verbal feedback (95%). Overall, students expressed that the feedback report was valuable, allowing for critical self-reflection and future retention. Staff have also found the application easy to use and administer.In a time- and resource-constrained teaching environment, educators constantly explore technology to support student learning and teaching outcomes. We have implemented an application that is user-friendly to staff, efficient, and has provided effective feedback that is well-received and valued by students.
Publisher: Springer Science and Business Media LLC
Date: 17-09-2019
DOI: 10.1038/S41467-019-12242-1
Abstract: Studies of rodent models of Alzheimer’s disease (AD) and of human tissues suggest that the retinal changes that occur in AD, including the accumulation of amyloid beta (Aβ), may serve as surrogate markers of brain Aβ levels. As Aβ has a wavelength-dependent effect on light scatter, we investigate the potential for in vivo retinal hyperspectral imaging to serve as a biomarker of brain Aβ. Significant differences in the retinal reflectance spectra are found between in iduals with high Aβ burden on brain PET imaging and mild cognitive impairment ( n = 15), and age-matched PET-negative controls ( n = 20). Retinal imaging scores are correlated with brain Aβ loads. The findings are validated in an independent cohort, using a second hyperspectral camera. A similar spectral difference is found between control and 5xFAD transgenic mice that accumulate Aβ in the brain and retina. These findings indicate that retinal hyperspectral imaging may predict brain Aβ load.
Publisher: Elsevier BV
Date: 12-2022
Publisher: Frontiers Media SA
Date: 2020
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 07-02-2020
DOI: 10.1167/IOVS.61.2.2
Publisher: Springer Singapore
Date: 2019
Publisher: Springer Singapore
Date: 2019
Publisher: Springer Science and Business Media LLC
Date: 09-05-2022
DOI: 10.1038/S41598-022-11495-Z
Abstract: In addition to well characterized motor symptoms, visual disturbances are increasingly recognized as an early manifestation in Parkinson’s disease (PD). A better understanding of the mechanisms underlying these changes would facilitate the development of vision tests which can be used as preclinical biomarkers to support the development of novel therapeutics for PD. This study aims to characterize the retinal phenotype of a mouse model of dopaminergic dysfunction and to examine whether these changes are reversible with levodopa treatment. We use a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD to characterize the neurotoxic effects of MPTP on in vivo retinal function (electroretinography, ERG), retinal structure (optical coherence tomography, OCT) and retinal dopaminergic cell number (tyrosine hydroxylase immunohistochemistry, IHC) at two time points (21 and 45 days) post MPTP model induction. We also investigate the effect of levodopa (L-DOPA) as a proof-of-principle chronic intervention against MPTP-induced changes in the retina. We show that MPTP decreases dopaminergic amacrine cell number (9%, p 0.05) and that a component of the ERG that involves these cells, in particular oscillatory potential (OP) peak timing, was significantly delayed at Day 45 (7–13%, p 0.01). This functional deficit was paralleled by outer plexiform layer (OPL) thinning ( p 0.05). L-DOPA treatment ameliorated oscillatory potential deficits (7–13%, p 0.001) in MPTP animals. Our data suggest that the MPTP toxin slows the timing of inner retinal feedback circuits related to retinal dopaminergic pathways which mirrors findings from humans with PD. It also indicates that the MPTP model causes structural thinning of the outer retinal layer on OCT imaging that is not ameliorated with L-DOPA treatment. Together, these non-invasive measures serve as effective biomarkers for PD diagnosis as well as for quantifying the effect of therapy.
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 29-06-2016
Abstract: We previously reported that applying toll-like receptor (TLR) ligands to an injured cornea induces corneal edema at 24 hours, which subsides by 1 week. We tested the hypotheses that endothelial expression of the tight-junction protein, zonula occludens-1 (ZO-1), would be altered during experimental sterile corneal inflammation and that endothelial cell density (ECD) would remain unaffected. Anesthetized C57BL/6J mice received central 1-mm corneal abrasions followed by topical application of saline or cytosine-phosphate-guanosine oligodeoxynucleotide (CpG-ODN, TLR-9 agonist). At 24 hours, 1 week and 4 weeks post treatment, spectral-domain optical coherence tomography images were captured. Eyes were enucleated and processed for zonula occludens-1 (ZO-1) immunofluorescent staining. Corneal flatmounts were analyzed for endothelial ZO-1 expression, cell density, polymegethism, and polymorphism. Corneal stromal inflammatory cell infiltration was evaluated at 4 weeks by immunostaining for CD45. Central corneal thickness (CCT) was increased in CpG-ODN treated eyes at 24 hours, had normalized by 1 week, but was again thickened by 4 weeks. In eyes with CpG-ODN, endothelial cell ZO-1 expression was reduced at 24 hours but returned to normal levels by 1 week. Endothelial cell density was not altered at 24 hours or 1 week. By 4 weeks, only CpG-ODN eyes showed relatively reduced ECD, as well as large numbers of CD45+ cells in the stroma. Changes to ECD correlated with CCT (r = -0.53, P < 0.01). Compared with naïve controls, more saline- and CpG-ODN-treated eyes exhibited polymegethism. This study provides novel insights into the interplay between endothelial cell integrity, corneal edema, and chronic stromal leukocyte activation during sterile corneal inflammation in mice.
Publisher: Informa UK Limited
Date: 28-04-2022
DOI: 10.1080/08164622.2022.2067471
Abstract: The use of chloroquine or hydroxychloroquine can lead to both acute and chronic changes to both retinal structure and function. Chloroquine (CQ) and hydroxychloroquine (HCQ) have the potential for retina toxicity. The acute impact of short-term drug exposure (2-4 weeks) on in vivo retinal structure and function and assess whether short wavelength light exposure further exacerbates any structural and functional changes was assessed in a murine model. Adult C57BL/6 J mice received intraperitoneal injection of vehicle or hydroxychloroquine (10 mg/kg) 3 times per week for 2 or 4 weeks, or chloroquine for 4 weeks (10 mg/kg). Over this period, animals were exposed to room light (8 hours) or short-wavelength light 4 hours per day (4 hours of normal room light) for 5 days each week. Retinal changes were assessed using electroretinography (ERG), in vivo optical coherence tomography (OCT) imaging. Short-term low-dose HCQ and CQ treatment led to RPE thickening and elongation of photoreceptors. These structural changes were associated with a no dysfunction in the case of HCQ treatments and widespread functional changes (photoreceptor sensitivity, bipolar cell litude and oscillatory potential litude) in the case of CQ treatment. Exposure to low intensity short-wavelength light does not appear to alter the effect of HCQ or CQ. HCQ and CQ treatment has acute effects on both retinal structure and function, effects that were not exacerbated by short wavelength light exposure. Whether chronic short wavelength light exposure exacerbates these changes require further study.
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 29-06-2016
Abstract: Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated protein (Cas) has recently been adapted to enable efficient editing of the mammalian genome, opening novel avenues for therapeutic intervention of inherited diseases. In seeking to disrupt yellow fluorescent protein (YFP) in a Thy1-YFP transgenic mouse, we assessed the feasibility of utilizing the adeno-associated virus 2 (AAV2) to deliver CRISPR/Cas for gene modification of retinal cells in vivo. Single guide RNA (sgRNA) plasmids were designed to target YFP, and after in vitro validation, selected guides were cloned into a dual AAV system. One AAV2 construct was used to deliver Streptococcus pyogenes Cas9 (SpCas9), and the other delivered sgRNA against YFP or LacZ (control) in the presence of mCherry. Five weeks after intravitreal injection, retinal function was determined using electroretinography, and CRISPR/Cas-mediated gene modifications were quantified in retinal flat mounts. Adeno-associated virus 2-mediated in vivo delivery of SpCas9 with sgRNA targeting YFP significantly reduced the number of YFP fluorescent cells of the inner retina of our transgenic mouse model. Overall, we found an 84.0% (95% confidence interval [CI]: 81.8-86.9) reduction of YFP-positive cells in YFP-sgRNA-infected retinal cells compared to eyes treated with LacZ-sgRNA. Electroretinography profiling found no significant alteration in retinal function following AAV2-mediated delivery of CRISPR/Cas components compared to contralateral untreated eyes. Thy1-YFP transgenic mice were used as a rapid quantifiable means to assess the efficacy of CRISPR/Cas-based retinal gene modification in vivo. We demonstrate that genomic modification of cells in the adult retina can be readily achieved by viral-mediated delivery of CRISPR/Cas.
Publisher: Elsevier BV
Date: 07-2017
DOI: 10.1016/J.PHARMTHERA.2017.02.009
Abstract: The retina is an easily accessible out-pouching of the central nervous system (CNS) and thus lends itself to being a biomarker of the brain. More specifically, the presence of neuronal, vascular and blood-neural barrier parallels in the eye and brain coupled with fast and inexpensive methods to quantify retinal changes make ocular biomarkers an attractive option. This includes its utility as a biomarker for a number of cerebrovascular diseases as well as a drug pharmacology and safety biomarker for the CNS. It is a rapidly emerging field, with some areas well established, such as stroke risk and multiple sclerosis, whereas others are still in development (Alzheimer's, Parkinson's, psychological disease and cortical diabetic dysfunction). The current applications and future potential of retinal biomarkers, including potential ways to improve their sensitivity and specificity are discussed. This review summarises the existing literature and provides a perspective on the strength of current retinal biomarkers and their future potential.
Publisher: Springer Science and Business Media LLC
Date: 18-09-2022
DOI: 10.1038/S41598-021-85554-2
Abstract: Hyperspectral imaging of the retina has recently been posited as a potentially useful form of spectroscopy of amyloid-beta (Aβ) protein in the eyes of those with Alzheimer’s disease (AD). The concept of using the retina as a biomarker for AD is an attractive one, as current screening tools for AD are either expensive or inaccessible. Recent studies have investigated hyperspectral imaging in Aβ models however these studies have been in younger mice. Here we characterised hyperspectral reflectance profile in 6 to 17 months old 5xFAD mice and compare this to Aβ in isolated preparations. Hyperspectral imaging was conducted across two preparations of Aβ using a custom built bench ophthalmoscope. In the in vitro condition, 1 mg of purified human Aβ42 was solubilised and left to aggregate for 72 h. This soluble/insoluble Aβ mixture was then imaged by suspending the solution at a pipette tip and compared against phosphate buffered saline (PBS) control (n = 10 ROIs / group). In the in vivo condition, a 5xFAD transgenic mouse model was used and retinae were imaged at the age of 6 (n = 9), 12 (n = 9) and 17 months (n = 8) with age matched wildtype littermates as control (n = 12, n = 13, n = 15 respectively). In the vitro condition, hyperspectral imaging of the solution showed greater reflectance compared with vehicle ( p 0.01), with the greatest differences occurring in the short visible spectrum ( 500 nm). In the in vivo preparation, 5xFAD showed greater hyperspectral reflectance at all ages (6, 12, 17 months, p 0.01). These differences were noted most in the short wavelengths at younger ages, with an additional peak appearing at longer wavelengths (~ 550 nm) with advancing age. This study shows that the presence of Aβ (soluble/insoluble mixture) can increase the hyperspectral reflectance profile in vitro as well as in vivo. Differences were evident in the short wavelength spectrum ( 500 nm) in vitro and were preserved when imaged through the ocular media in the in vivo conditions. With advancing age a second hump around ~ 550 nm became more apparent. Hyperspectral imaging of the retina does not require the use of contrast agents and is a potentially useful and non-invasive biomarker for AD.
Publisher: Cold Spring Harbor Laboratory
Date: 21-08-2019
DOI: 10.1101/742494
Abstract: Executive function deficits in Alzheimer’s disease (AD) occur early in disease progression and may be predictive of cognitive decline. However, no preclinical studies have identified deficits in rewarded executive function in the commonly used APP/PS1 mouse model. To address this, we assessed 12-26 month old APP/PS1 mice on rewarded reversal and/or extinction tasks. 16-month-old, but not 13- or 26-month-old, APP/PS1 mice showed an attenuated rate of extinction. Reversal deficits were seen in 22-month-old, but not 13-month-old APP/PS1 animals. We then confirmed that impairments in reversal were unrelated to previously reported visual impairments in both AD mouse models and humans. Age, but not genotype, had a significant effect on markers of retinal health, indicating the deficits seen in APP/PS1 mice were directly related to cognition. This is the first characterisation of rewarded executive function in APP/PS1 mice, and has great potential to facilitate translation from preclinical models to the clinic.
Publisher: Informa UK Limited
Date: 06-03-2022
DOI: 10.1080/08164622.2022.2033106
Abstract: The aim of this study was to review all the articles that have implemented patient-reported outcome measures (PROMs) to evaluate the quality of life (QoL) in corneal transplantation and discuss quality assessments of the PROMs. An extensive literature review was undertaken to identify all the studies that used PROMs to assess the QoL in corneal transplantation. Non-original or review articles, articles on other subject area and articles on cost-effectiveness/utility without PROM data/results were excluded. Each PROM was assessed against the following criteria: content development (item identification and item selection), psychometric properties, validity, reliability, and responsiveness. 425 articles were identified of which 35 articles were included in the final review. PROMs in corneal transplantation were used to (a) evaluate the QoL after surgery, (b) compare the QoL scores between different surgical techniques and (c) determine the relationship between QoL and objective measures such as visual acuity, visual field and stereoacuity. A total of 17 PROMs were used to assess QoL in corneal transplantation. Whilst this search did not produce any PROMs that were specifically designed to assess corneal transplantation, most studies were found to have employed the National Eye Institute Visual Function Questionnaire 25 (NEI VFQ 25). The Visual Function Index 14 (VF 14) performed better in the present quality assessment criteria compared to other PROMs, however, the NEI VFQ 25 and the VF 14 PROMs were not specifically developed for corneal transplantation and therefore the QoL assessment made using these PROMs may be incomplete. As improvements in various forms of lamellar transplantation surgery techniques such as UT-DSAEK and FT-DSAEK have resulted in better visual outcomes, improved graft survival and reduced complications, a corneal transplantation specific PROM will be useful in clinical settings to compare the outcomes of different surgical techniques from the patient perspective.
Publisher: Frontiers Media SA
Date: 17-11-2016
Publisher: Elsevier BV
Date: 05-2021
DOI: 10.1016/J.PRETEYERES.2020.100899
Abstract: Alzheimer's Disease (AD) is a devastating neurodegenerative disorder of the brain, clinically characterised by cognitive deficits that gradually worsen over time. There is, at present, no established cure, or disease-modifying treatments for AD. As life expectancy increases globally, the number of in iduals suffering from the disease is projected to increase substantially. Cumulative evidence indicates that AD neuropathological process is initiated several years, if not decades, before clinical signs are evident in patients, and diagnosis made. While several imaging, cognitive, CSF and blood-based biomarkers have been proposed for the early detection of AD their sensitivity and specificity in the symptomatic stages is highly variable and it is difficult to justify their use in even earlier, pre-clinical stages of the disease. Research has identified potentially measurable functional, structural, metabolic and vascular changes in the retina during early stages of AD. Retina offers a distinctively accessible insight into brain pathology and current and developing ophthalmic technologies have provided us with the possibility of detecting and characterising subtle, disease-related changes. Recent human and animal model studies have further provided mechanistic insights into the biochemical pathways that are altered in the retina in disease, including amyloid and tau deposition. This information coupled with advances in molecular imaging has allowed attempts to monitor biochemical changes and protein aggregation pathology in the retina in AD. This review summarises the existing knowledge that informs our understanding of the impact of AD on the retina and highlights some of the gaps that need to be addressed. Future research will integrate molecular imaging innovation with functional and structural changes to enhance our knowledge of the AD pathophysiological mechanisms and establish the utility of monitoring retinal changes as a potential biomarker for AD.
Publisher: Frontiers Media SA
Date: 13-08-2020
Publisher: Public Library of Science (PLoS)
Date: 27-05-2014
Publisher: Elsevier BV
Date: 12-2021
DOI: 10.1016/J.NEUROBIOLAGING.2021.08.004
Abstract: Executive function deficits in Alzheimer's disease (AD) occur early in disease progression and may be predictive of cognitive decline. However, no preclinical studies have identified deficits in rewarded executive function in the commonly used APPSwe/PS1∆E9 (APP/PS1) mouse model. To address this, we assessed 12-26 month old APP/PS1 mice on rewarded reversal and/or extinction tasks. 16-month-old, but not 13- or 26-month-old, APP/PS1 mice showed an attenuated rate of extinction. Reversal deficits were seen in 22-month-old, but not 13-month-old APP/PS1 animals. We then confirmed that impairments in reversal were unrelated to previously reported visual impairments in both AD mouse models and humans. Age, but not genotype, had a significant effect on markers of retinal health, indicating the deficits seen in APP/PS1 mice were directly related to cognition. This is the first characterisation of rewarded executive function in APP/PS1 mice, and has great potential to facilitate translation from preclinical models to the clinic.
Publisher: Frontiers Media SA
Date: 09-12-2020
DOI: 10.3389/FNINS.2020.556137
Abstract: There has been increasing interest in identifying non-invasive, imaging biomarkers for neurodegenerative disorders of the central nervous system (CNS). The aim of this proof-of-concept study was to investigate whether corneal sensory nerve and dendritic cell (DC) parameters, captured using in vivo confocal microscopy (IVCM), are altered in in iduals with mild cognitive impairment (MCI) and Alzheimer’s disease (AD). Fifteen participants were recruited from the Australian Imaging Biomarkers and Lifestyle (AIBL) study in Melbourne, VIC, Australia. The cohort consisted of cognitively normal (CN) in iduals ( n = 5), and those with MCI ( n = 5) and AD ( n = 5). Participants underwent a slit l examination of the anterior segment, followed by corneal imaging using laser-scanning in vivo confocal microscopy (IVCM) of the central and inferior whorl regions. Corneal DC density, field area, perimeter, circularity index, aspect ratio, and roundness were quantified using Image J. Quantitative data were derived for corneal nerve parameters, including nerve fiber length (CNFL), fiber density (CNFD), branch density (CNBD), and diameter. Corneal DC field area and perimeter were greater in in iduals with MCI, relative to CN controls, in both the central and inferior whorl regions ( p & 0.05 for all comparisons). In addition, corneal DCs in the whorl region of MCI eyes had lower circularity and roundness indices and a higher aspect ratio relative to CNs ( p & 0.05 for all comparisons). DC density was similar across participant groups in both corneal regions. There was a trend toward lower quantitative parameters for corneal nerve architecture in the AD and MCI groups compared with CN participants, however, the inter-group differences did not reach statistical significance. Central corneal nerve diameters were similar between groups. This study is the first to report morphological differences in corneal DCs in humans with MCI. These differences were evident in both the central and mid-peripheral cornea, and in the absence of significant nerve abnormalities or a difference in DC density. These findings justify future large-scale studies to assess the utility of corneal IVCM and DC analysis for identifying early stage pathology in neurodegenerative disorders of the CNS.
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 12-2016
Abstract: To describe a mouse model of hyperoxia-induced vitreoretinopathy that replicated some of the clinical and pathologic features encountered in infants with severe retinopathy of prematurity and congenital ocular conditions such as persistent hyperplastic primary vitreous. Experimental mice (C57BL/6J) were exposed to 65% oxygen between postnatal days (P)0 to P7 and studied at P10, P14, and 3, 5, 8, 20, and 40 weeks. Controls were exposed to normoxic conditions. Fundus imaging and fluorescein angiography were performed at all time points, and spectral-domain optical coherence tomography (SD-OCT) and electroretinography were performed at 8- and 20-week time points. Eyes were processed for resin histology, frozen sections, and retinal whole mounts. Immunostaining was performed to visualize vasculature isolectin B4 (Ib4), collagen type IV, glial fibrillary acidic protein, and α-smooth muscle actin. Early exposure to hyperoxia resulted in bilateral vitreous hemorrhages at 3 weeks. From 5 weeks onward there were extensive zones of retinal degeneration, scarring or gliosis, retinal folding, and detachments caused by traction of α-smooth muscle actin-positive vitreous membranes. Tortuous retinal vessels, together with hyperplastic and persistence of hyaloid vessels are evident into adulthood. In the early stages (P10-3 weeks), branches from the tunica vasculosa lentis (TVL) supplied the marginal retina until retinal vessels were established. The peripheral retina remained poorly vascularized into adulthood. Electroretinography revealed 50% to 60% diminution in retinal function in adult mice that strongly correlated with vitreal changes identified using SD-OCT. This animal model displays a mixture of vitreoretinal pathologic changes that persist into adulthood. The model may prove valuable in experimental investigations of therapeutic approaches to blinding conditions caused by vitreous and retinal abnormalities.
Publisher: Wiley
Date: 08-2013
DOI: 10.1002/PHY2.55
Publisher: MyJove Corporation
Date: 05-10-2018
DOI: 10.3791/58287
Publisher: Frontiers Media SA
Date: 02-08-2023
DOI: 10.3389/FNINS.2023.1215097
Abstract: The retina and brain share similar neurochemistry and neurodevelopmental origins, with the retina, often viewed as a “window to the brain.” With retinal measures of structure and function becoming easier to obtain in clinical populations there is a growing interest in using retinal findings as potential biomarkers for disorders affecting the central nervous system. Functional retinal biomarkers, such as the electroretinogram, show promise in neurological disorders, despite having limitations imposed by the existence of overlapping genetic markers, clinical traits or the effects of medications that may reduce their specificity in some conditions. This narrative review summarizes the principal functional retinal findings in central nervous system disorders and related mouse models and provides a background to the main excitatory and inhibitory retinal neurotransmitters that have been implicated to explain the visual electrophysiological findings. These changes in retinal neurochemistry may contribute to our understanding of these conditions based on the findings of retinal electrophysiological tests such as the flash, pattern, multifocal electroretinograms, and electro-oculogram. It is likely that future applications of signal analysis and machine learning algorithms will offer new insights into the pathophysiology, classification, and progression of these clinical disorders including autism, attention deficit/hyperactivity disorder, bipolar disorder, schizophrenia, depression, Parkinson’s, and Alzheimer’s disease. New clinical applications of visual electrophysiology to this field may lead to earlier, more accurate diagnoses and better targeted therapeutic interventions benefiting in idual patients and clinicians managing these in iduals and their families.
Publisher: Frontiers Media SA
Date: 10-02-2017
No related grants have been discovered for Jeremiah Lim.