Clinical School (Royal Melbourne Hospital)

Genes implicated in multiple sclerosis pathogenesis from consilience of genotyping and expression profiles in relapse and remission

2020-10-06T04:48:07Z

Arthur, AT; Armati, PJ; Bye, C; Heard, RNS; Stewart, GJ; Pollard, JD; Booth, DR 2008-03-19 Genes implicated in multiple sclerosis pathogenesis from consilience of genotyping and expression profiles in relapse and remission BACKGROUND: Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS). Although the pathogenesis of MS remains unknown, it is widely regarded as an autoimmune disease mediated by T-lymphocytes directed against myelin proteins and/or other oligodendrocyte epitopes. METHODS: In this study we investigated the gene expression profiles of peripheral blood cells from patients with RRMS during the relapse and the remission phases utilizing gene microarray technology. Dysregulated genes encoded in regions associated with MS susceptibility from genomic screens or previous transcriptomic studies were identified. The proximal promoter region polymorphisms of two genes were tested for association with disease and expression level. RESULTS: Distinct sets of dysregulated genes during the relapse and remission phases were identified including genes involved in apoptosis and inflammation. Three of these dysregulated genes have been previously implicated with MS susceptibility in genomic screens: TGFbeta1, CD58 and DBC1. TGFbeta1 has one common SNP in the proximal promoter: -508 T>C (rs1800469). Genotyping two Australian trio sets (total 620 families) found a trend for over-transmission of the T allele in MS in females (p < 0.13). Upregulation of CD58 and DBC1 in remission is consistent with their putative roles in promoting regulatory T cells and reducing cell proliferation, respectively. A fourth gene, ALOX5, is consistently found over-expressed in MS. Two common genetic variants were confirmed in the ALOX5 putative promoter: -557 T>C (rs12762303) and a 6 bp tandem repeat polymorphism (GGGCGG) between position -147 and -176; but no evidence for transmission distortion found. CONCLUSION: The dysregulation of these genes tags their metabolic pathways for further investigation for potential therapeutic intervention. Journal Article

Indonesian medical interns’ experiences and self-perceptions of competency development during their internship year

2020-11-04T07:26:59Z

Lanuma, Eddy Kartadjukardi 2018 Indonesian medical interns’ experiences and self-perceptions of competency development during their internship year This thesis focuses on the experiences of Indonesian medical graduates and their perceptions of the development of their own competency whilst undertaking a one-year medical internship program. The Indonesian medical curriculum has undergone significant changes in the last decade that have been concurrent with increasing demands for qualified medical practitioners. Under the current system, new graduates are required to complete eight months of internship training in a public hospital and four months of training in a primary health care centre before they qualify for independent practice. This research is the first, in the Indonesian context, to explore interns’ experiences and the factors that influence internship outcomes. It also contributes to addressing a large gap in our understanding of how internship programs function and the challenges they face within resource-constrained low- and middle-income countries (referred to collectively as lower-income countries hereafter). The thesis is based on a mixed quantitative and qualitative research design that collected primary data in Indonesia from 2013 to 2014. The quantitative component was conducted in 22 out of the 27 Indonesian provinces that run internship programs. The self-perceived competency of 970 interns was assessed both pre- and post- internship. For the qualitative component, a case study approach was applied to gain insight into interns’ experiences before and after their four-month placements in primary health care centres and their eight-month placements in hospitals. In the qualitative interviews, 13 interns were asked to describe their perceptions of their competency development during their internship year, their changes in competency, and the factors that were most influential in shaping competency development. Eight intern mentors were also interviewed to gain insight into how well the internship program achieved its objectives, and to understand mentors’ relationships with, and attitudes towards interns. The findings of the pre- and post-internship surveys indicated that interns perceived generally increased confidence in their core competencies compared to their pre-internship baseline. However, interns’ attributes, such as educational background, personal characteristics and the province they were posted to for internship training, had no significant impact on their perceptions of pre- and post-internship competency. While the survey results indicated that interns generally felt better equipped to undertake general practice at the end of their internships, the qualitative data revealed a range of factors that influenced the degree to which interns felt they could maximise their competency development during the internship year. Interns identified both personal attributes and systemic factors as being influential in shaping the success of their internship. Interns perceived that the process of developing competencies during internship required cultural competency and effective communication with the Internship Committee, mentors, senior staff at internship training placements, patients, and patients’ families and communities. Additionally, the study documented how systemic factors, such as health facility infrastructure, quality of mentorship and health centre management, positively and negatively affected interns’ motivations and experiences in developing their competencies. This thesis makes important contributions to the study of internship programs in Indonesia and in lower-income contexts more broadly. Firstly, it identifies and discusses the significance of the broad health system conditions within which internship programs are situated and how this influences their success. Secondly, it highlights the need for a standardised national internship curriculum to improve internship experiences, as well as a curriculum that can respond to differing levels of learning opportunities within a health system that has varied levels of infrastructure and human resources. Thirdly, my analysis involved the adaptation and application of Deci et al.’s self-determination theory (1) to intern motivation in the Indonesian context. This revealed that, for cultural reasons, Indonesian interns are more inclined to develop extrinsic motivation to practice medicine in their internship year, rather than the intrinsic motivation that is assumed to dominate in Western studies of intern motivation. The thesis also provides practical recommendations for strengthening Indonesia’s current internship program to better achieve its objectives and to respond to the experiences and perceptions of interns. These include: developing a more effective communication strategy between the different stakeholders involved in the program, increasing interns’ cultural competency, improving the infrastructure at internship training centres, developing protocols for ensuring patient safety, improving the quality of mentoring, and stipulating clear guidelines that ensure good-quality management structures at internship training centres. © 2018 Dr. Eddy Kartadjukardi Lanuma PhD thesis

Innate cellular responses to malaria in children and pregnant women

2020-11-04T08:31:50Z

Njie, Madi 2018 Innate cellular responses to malaria in children and pregnant women Malaria is one of the leading causes of morbidity and mortality in young African children and pregnant women. Clinical presentations and outcomes of P. falciparum infections are influenced by a combination of host, parasite and environmental factors. In the absence of an effective vaccine, it is important to understand how parasite and environmental factors interact with host innate immunity to influence disease severity in paediatric and pregnancy-related malaria. Aim 1, investigated the association between P. falciparum erythrocyte membrane protein 1 (PfEMP1) and inflammatory responses in clinical malaria syndromes. Malaria-infected erythrocytes (IE) were isolated from Malawian children with cerebral or uncomplicated malaria to compare their PfEMP1 profiles and cytokine elicitation capacity on malaria naïve PBMC. Also, Monocyte-derived macrophages (MDM) from Melbourne donors were exposed to isogenic parasite lines with different PfEMP1 phenotypes including (CS2: CSA binder; P6A1: CD36 binder; P6G2: CD36; E8B: CD36 and ICAM-1 binders) to determine whether PfEMP1 binding characteristics influence cytokine production. According to the var typing data of the clinical parasites from Malawi, the transcription of group A PfEMP1 was significantly higher in cerebral malaria isolates compared to the uncomplicated malaria isolates. Following in vitro stimulation of PBMC, IE from cerebral malaria isolates induced higher pro-inflammatory cytokines compared to the uncomplicated malaria isolates, suggesting a relationship between PfEMP1 expression and the elicited cytokine responses. Furthermore, MDM stimulations with CD36 binding parasites generated significantly lower inflammatory cytokines compared to the non-CD36 binding line. Together, findings of this study suggest that PfEMP1 binding phenotypes influence inflammatory responses and consequently disease severity. In Aim 2, innate cellular responses in acute and convalescence were compared between children with cerebral and uncomplicated malaria from Malawi. The objective was to evaluate the influence of inflammatory responses and monocyte subpopulations in malaria severity. Plasma levels of inflammatory cytokines and the proportion of monocyte subsets were analysed at presentation (day 0) and follow-up (day 28). Although inflammatory cytokine levels were significantly elevated during acute infection, responses were similar between cerebral and uncomplicated malaria. Consistently, monocyte profiles were not different between the two malaria groups. Aim 3, was to investigate the eﬀects of factors such as gravidity, lifetime malaria exposure, active malaria infection and different P. falciparum strains on maternal innate immunity. PBMC from primigravidae and multigravidae pregnant women from Papua New Guinea (PNG) (with or without current infection) and Australia were stimulated with CS2-IE (CSA binder), P6A1-IE (CD36 binder) or controls (PHA & uRBC). In this study, PBMC responses were not influenced by gravidity in both study cohort or current malaria infection among PNG women. Compared to samples for Australia, PBMC from PNG produced significantly higher cytokine levels to both CS2-IE and PHA, suggesting a geography-related influence not entirely specific to malaria exposure. Between the two parasite lines, PBMC stimulations with CS2-IE elicited higher responses for some cytokines compared to P6A1-IE. These observations suggest that maternal innate immunity to malaria is influenced by geographic origin and different P. falciparum strains. The findings from these studies have added to our current understanding of P. falciparum-induced immunopathology and identified mechanisms that could be exploited for the development of new intervention strategies targeted towards innate immune modulation. © 2018 Dr. Madi Njie PhD thesis

Understanding innate immunity to Plasmodium falciparum malaria

2020-11-04T06:38:05Z

Jabbarzare, Marzieh 2017 Understanding innate immunity to Plasmodium falciparum malaria The malaria parasite Plasmodium falciparum still causes an incredibly high number of deaths in young children under the age of five and pregnant women annually. The pathogenesis of human malaria is due to a combination of several parasite and host factors that simultaneously influence the severity and outcome of disease. Thus, a better understanding of the roles played by innate immune cells in both pregnancy and non-pregnancy related malaria infection is crucial. In Aim 1, an in vitro model of human peripheral blood mononuclear cells (PBMCs) derived from non-immune individuals were exposed to infected erythrocytes (IEs) expressing different P. falciparum erythrocyte membrane protein 1 (PfEMP1) binding phenotypes. This included IT parasites lines (CS2, a placental parasite line expressing VAR2CSA which binds to chondroitin sulfate A (CSA) and E8B (CD36 binding)) and NF54 lines (3C (non-CD36 binding) and 3D7 (CD36 binding)). The objectives were to identify whether PfEMP1 binding phenotypes influence PBMCs cytokine response, and also to determine whether CD36 binding is parasite characteristic that influences the innate immune response. Higher cytokines secretions were observed when PBMCs were stimulated with non-CD36 binding IEs in comparison with CD36 binding IEs. Furthermore, γδ T cells represented the predominant source of IFNγ in PBMCs from naïve donors stimulated with P. falciparum IEs. The focus of Aim 2 was to investigate the ability of purified in vitro expanded γδ T cells to produce cytokines when exposed to P. falciparum IEs with different variant surface antigens. It was found that these cells can be directly activated by P. falciparum IEs. Furthermore, cytokine secretion was not substantially different in response to parasite lines expressing different PfEMP1 types. Moreover, the contribution of Vδ2+ γδ T cells to the production of IFNγ was significantly higher than that of Vδ2- γδ T cells. Nonetheless, the activation of Vδ2- γδ T cells represented an unanticipated and intriguing result in the present study. Examining the culture of Vδ2 depleted γδ T cells, a significant ability of them to produce cytokines (IFNγ, GMCSF and TNFα) was observed following exposure to P. falciparum IEs. Furthermore, activation of these cells by P. falciparum IEs for IFNγ production was highly dependent on the direct contact between the cells and the whole IEs. This activation was shown to be sensitive to trypsin digestion but not lack of expression of PfEMP1. Considering both complete and Vδ2 depleted γδ T cell cultures, it was found that the activation modes of γδ T cells subsets appeared to be different in presence or absence of Vδ2. Two different mechanisms of activation of Vδ1 and Vδ1-Vδ2- γδ T cell subsets in presence or absence of Vδ2 γδ T cells were also proposed in this study. The goal of Aim 3 was to assess the effect of various factors such as active malaria infection, life time malaria exposure and gravidity on the maternal innate immune responses. PBMCs derived from Papua New Guinea (PNG) (highly endemic area) pregnant women with and without current malaria infection and Melbourne pregnant women (non-endemic area) were exposed to P. falciparum CS2-IEs for 24 hours. The present study found that among PBMCs derived from PNG pregnant women, presence of microscopic malaria infection did not alter either secretion of IFNγ or proportion of innate immune cells positive for induction of IFNγ. With regard to malaria exposure, a significant increase in IFNγ production was observed in response to both P. falciparum CS2-IEs and Phytohaemagglutinin (PHA) in PNG samples compared to Melbourne samples. This observation was shown to be associated with significantly more active natural killer cells (NK cells) in pregnant women living in PNG. Considering the effect of gravidity, a significant elevation of IFNγ secretion in multigravidae group was observed compared to primigravidae group in PNG pregnant women (a similar, non-significant trend in Melbourne pregnant women) in response to P. falciparum CS2-IEs. This observation could be explained by the observed percentages of IFNγ producing γδ T cells and specially their Vδ2 subset being substantially higher in multigravidae women compared to primigravid women in PNG group. Together, these results suggested that the combination of exposure, not entirely specific to malaria, and gravidity significantly impacts innate immune response in pregnant women. The outcomes of these studies led to new insights that might contribute to development of new strategies in modulating the innate immune system and particularly to increasing proportions of IFNγ producing γδ T cells to safely prevent or diminish P. falciparum-induced immunopathology. © 2018 Dr. Marzieh Jabbarzare PhD thesis

Understanding factors influencing physical activity and exercise in lung cancer: a systematic review

2020-11-26T12:39:52Z

Granger, CL; Connolly, B; Denehy, L; Hart, N; Antippa, P; Lin, K-Y; Parry, SM 2017-03-01 Understanding factors influencing physical activity and exercise in lung cancer: a systematic review PURPOSE: Despite evidence and clinical practice guidelines supporting physical activity (PA) for people with lung cancer, this evidence has not translated into clinical practice. This review aims to identify, evaluate and synthesise studies examining the barriers and enablers for patients with lung cancer to participate in PA from the perspective of patients, carers and health care providers (HCPs). METHODS: Systematic review of articles using electronic databases: MEDLINE (1950-2016), CINAHL (1982-2016), EMBASE (1980-2016), Scopus (2004-2016) and Cochrane (2016). Quantitative and qualitative studies, published in English in a peer-reviewed journal, which assessed the barriers or enablers to PA for patients with lung cancer were included. Registered-PROSPERO (CRD4201603341). RESULTS: Twenty-six studies (n = 9 cross-sectional, n = 4 case series, n = 11 qualitative) including 1074 patients, 23 carers and 169 HCPs were included. Barriers and enablers to PA were identified (6 major themes, 18 sub-themes): Barriers included patient-level factors (physical capability, symptoms, comorbidities, previous sedentary lifestyle, psychological influences, perceived relevance), HCP factors (time/knowledge to deliver information) and environmental factors (access to services, resources, timing relative to treatment). Enablers included anticipated benefits, opportunity for behaviour change and influences from HCPs and carers. CONCLUSION: This systematic review has identified the volume of literature demonstrating that barriers and enablers to PA in lung cancer are multidimensional and span diverse factors. These include patient-level factors, such as symptoms, comorbidities, sedentary lifestyle, mood and fear, and environmental factors. These factors should be considered to identify and develop suitable interventions and clinical services in attempt to increase PA in patients with lung cancer. Journal Article

The &ITPlasmodium falciparum &ITtranscriptome in severe malaria reveals altered expression of genes involved in important processes including surface antigen-encoding &ITvar &ITgenes

2020-11-26T12:39:52Z

Tonkin-Hill, GQ; Trianty, L; Noviyanti, R; Nguyen, HHT; Sebayang, BF; Lampah, DA; Marfurt, J; Cobbold, SA; Rambhatla, JS; McConville, MJ; Rogerson, SJ; Brown, G; Day, KP; Price, RN; Anstey, NM; Papenfuss, AT; Duffy, MF 2018-03-01 The &ITPlasmodium falciparum &ITtranscriptome in severe malaria reveals altered expression of genes involved in important processes including surface antigen-encoding &ITvar &ITgenes Within the human host, the malaria parasite Plasmodium falciparum is exposed to multiple selection pressures. The host environment changes dramatically in severe malaria, but the extent to which the parasite responds to-or is selected by-this environment remains unclear. From previous studies, the parasites that cause severe malaria appear to increase expression of a restricted but poorly defined subset of the PfEMP1 variant, surface antigens. PfEMP1s are major targets of protective immunity. Here, we used RNA sequencing (RNAseq) to analyse gene expression in 44 parasite isolates that caused severe and uncomplicated malaria in Papuan patients. The transcriptomes of 19 parasite isolates associated with severe malaria indicated that these parasites had decreased glycolysis without activation of compensatory pathways; altered chromatin structure and probably transcriptional regulation through decreased histone methylation; reduced surface expression of PfEMP1; and down-regulated expression of multiple chaperone proteins. Our RNAseq also identified novel associations between disease severity and PfEMP1 transcripts, domains, and smaller sequence segments and also confirmed all previously reported associations between expressed PfEMP1 sequences and severe disease. These findings will inform efforts to identify vaccine targets for severe malaria and also indicate how parasites adapt to-or are selected by-the host environment in severe malaria. Journal Article

Intensive care discharge delay is associated with increased hospital length of stay: A multicentre prospective observational study

2020-11-26T12:39:52Z

Tiruvoipati, R; Botha, J; Fletcher, J; Gangopadhyay, H; Majumdar, M; Vij, S; Paul, E; Pilcher, D 2017-07-27 Intensive care discharge delay is associated with increased hospital length of stay: A multicentre prospective observational study BACKGROUND: Some patients experience a delayed discharge from the intensive care unit (ICU) where the intended and actual discharge times do not coincide. The clinical implications of this remain unclear. OBJECTIVE: To determine the incidence and duration of delayed ICU discharge, identify the reasons for delay and evaluate the clinical consequences. METHODS: Prospective multi-centre observational study involving five ICUs over a 3-month period. Delay in discharge was defined as >6 hours from the planned discharge time. The primary outcome measure was hospital length stay after ICU discharge decision. Secondary outcome measures included ICU discharge after-hours, incidence of delirium, survival to hospital discharge, discharge destination, the incidence of ICU acquired infections, revocation of ICU discharge decision, unplanned readmissions to ICU within 72 hours, review of patients admitting team after ICU discharge decision. RESULTS: A total of 955 out of 1118 patients discharged were included in analysis. 49.9% of the patients discharge was delayed. The most common reason (74%) for delay in discharge was non-availability of ward bed. The median duration of the delay was 24 hours. On univariable analysis, the duration of hospital stay from the time of ICU discharge decision was significantly higher in patients who had ICU discharge delay (Median days-5 vs 6; p = 0.003). After-hours discharge was higher in patients whose discharge was delayed (34% Vs 10%; p<0.001). There was no statistically significant difference in the other secondary outcomes analysed. Multivariable analysis adjusting for known confounders revealed delayed ICU discharge was independently associated with increased hospital length of stay. CONCLUSION: Half of all ICU patients experienced a delay in ICU discharge. Delayed discharge was associated with increased hospital length of stay. Journal Article

Barriers and strategies to achieve a cure for HIV

2020-11-26T12:39:52Z

Pitman, MC; Lau, JSY; McMahon, JH; Lewin, SR 2018-06-01 Barriers and strategies to achieve a cure for HIV 9 years since the report of a cure for HIV after C-C chemokine receptor type 5 Δ32 stem cell transplantation, no other case of HIV cure has been reported, despite much research. However, substantial progress has been made in understanding the biology of the latent HIV reservoir, and in measuring the amount of virus that persists after antiretroviral therapy (ART) with increasingly sophisticated approaches. This knowledge is being translated into a long pipeline of clinical trials seeking to reduce viral persistence in participants on suppressive treatment and ultimately to allow safe cessation of ART. In this Review, we discuss the main barriers preventing the development of an HIV cure, methods used to measure HIV persistence in individuals on ART, clinical strategies that aim to cure HIV, and future directions for studies in the field of HIV cure research. Journal Article

Diagnosis of interstitial cystitis/bladder pain syndrome in women with chronic pelvic pain: a prospective observational study

2020-11-26T12:39:52Z

Cheng, C; Rosamilia, A; Healey, M 2012-10-01 Diagnosis of interstitial cystitis/bladder pain syndrome in women with chronic pelvic pain: a prospective observational study INTRODUCTION AND HYPOTHESIS: This study assesses the prevalence of interstitial cystitis (IC)/bladder pain syndrome (BPS) in women with chronic pelvic pain (CPP). METHODS: This was a prospective study of 150 women undergoing laparoscopy as investigation for CPP in an Endometriosis and Pelvic Pain unit. Preoperative questionnaires [demographic details, pelvic pain symptoms, the Pelvic Pain and Urgency/Frequency (PUF) and O'Leary-Sant (OLS) Symptom and Problem Index scores] were completed, and concurrent standardized cystoscopy with hydrodistention performed at laparoscopy. The primary outcome measures the proportion of IC in this group, defined by presence of glomerulations with CPP and urinary symptoms (urinary frequency, nocturia, urgency). The secondary outcome measures the proportion of BPS [defined by the European Society of the Study of Interstitial Cystitis (ESSIC)]. RESULTS: IC was diagnosed in 48/150 (32%) individuals, and 80/150 (53%) had BPS. There were no significant differences in symptomatology or questionnaire results between groups with and without IC. Women with BPS had higher PUF (17.2 vs 12.9, p < 0.001), OLS Symptom (8.2 vs 6.0, p = 0.001) and Problem (7.5 vs 4.2, p < 0.001) scores and more severe pain symptoms. Visually proven endometriosis was seen in 90/150 (60%), and 27/150 (18%) had both endometriosis and IC. Of the 80 women with BPS, 45/80 (60%) had endometriosis. CONCLUSIONS: The prevalence of IC/BPS varies depending on the definition used. This study showed IC in 32% of women with CPP based on symptoms and presence of glomerulations. BPS as defined by ESSIC was diagnosed in 53%. History and questionnaires did not correlate with positive cystoscopic findings. Journal Article

Early acid-base and blood pressure effects of continuous renal replacement therapy intensity in patients with metabolic acidosis

2020-11-26T12:39:52Z

Bellomo, R; Lipcsey, M; Calzavacca, P; Haase, M; Haase-Fielitz, A; Licari, E; Tee, A; Cole, L; Cass, A; Finfer, S; Gallagher, M; Lee, J; Lo, S; McArthur, C; McGuinness, S; Myburgh, J; Scheinkestel, C 2013-03-01 Early acid-base and blood pressure effects of continuous renal replacement therapy intensity in patients with metabolic acidosis PURPOSE: In acute kidney injury patients, metabolic acidosis is common. Its severity, duration, and associated changes in mean arterial pressure (MAP) and vasopressor therapy may be affected by the intensity of continuous renal replacement therapy (CRRT). We aimed to compare key aspects of acidosis and MAP and vasopressor therapy in patients treated with two different CRRT intensities. METHODS: We studied a nested cohort of 115 patients from two tertiary intensive care units (ICUs) within a large multicenter randomized controlled trial treated with lower intensity (LI) or higher intensity (HI) CRRT. RESULTS: Levels of metabolic acidosis at randomization were similar [base excess (BE) of -8 ± 8 vs. -8 ± 7 mEq/l; p = 0.76]. Speed of BE correction did not differ between the two groups. However, the HI group had a greater increase in MAP from baseline to 24 h (7 ± 3 vs. 0 ± 3 mmHg; p < 0.01) and a greater decrease in norepinephrine dose (from 12.5 to 3.5 vs. 5 to 2.5 μg/min; p < 0.05). The correlation (r) coefficients between absolute change in MAP and norepinephrine (NE) dose versus change in BE were 0.05 and -0.37, respectively. CONCLUSIONS: Overall, LI and HI CRRT have similar acid-base effects in patients with acidosis. However, HI was associated with greater improvements in MAP and vasopressor requirements (clinical trial no. NCT00221013). Journal Article

Common and Low Frequency Variants in MERTK Are Independently Associated with Multiple Sclerosis Susceptibility with Discordant Association Dependent upon HLA-DRB1*15:01 Status

2020-11-26T12:39:52Z

Binder, MD; Fox, AD; Merlo, D; Johnson, LJ; Giuffrida, L; Calvert, SE; Akkermann, R; Ma, GZM; Perera, AA; Gresle, MM; Laverick, L; Foo, G; Fabis-Pedrini, MJ; Spelman, T; Jordan, MA; Baxter, AG; Foote, S; Butzkueven, H; Kilpatrick, TJ; Field, J 2016-03-01 Common and Low Frequency Variants in MERTK Are Independently Associated with Multiple Sclerosis Susceptibility with Discordant Association Dependent upon HLA-DRB1*15:01 Status Multiple Sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system. The risk of developing MS is strongly influenced by genetic predisposition, and over 100 loci have been established as associated with susceptibility. However, the biologically relevant variants underlying disease risk have not been defined for the vast majority of these loci, limiting the power of these genetic studies to define new avenues of research for the development of MS therapeutics. It is therefore crucial that candidate MS susceptibility loci are carefully investigated to identify the biological mechanism linking genetic polymorphism at a given gene to the increased chance of developing MS. MERTK has been established as an MS susceptibility gene and is part of a family of receptor tyrosine kinases known to be involved in the pathogenesis of demyelinating disease. In this study we have refined the association of MERTK with MS risk to independent signals from both common and low frequency variants. One of the associated variants was also found to be linked with increased expression of MERTK in monocytes and higher expression of MERTK was associated with either increased or decreased risk of developing MS, dependent upon HLA-DRB1*15:01 status. This discordant association potentially extended beyond MS susceptibility to alterations in disease course in established MS. This study provides clear evidence that distinct polymorphisms within MERTK are associated with MS susceptibility, one of which has the potential to alter MERTK transcription, which in turn can alter both susceptibility and disease course in MS patients. Journal Article

The role of impairment of mesenchymal stem cell function in osteoporotic bone fracture healing

2020-11-26T12:39:52Z

Zhang, L; Miramini, S; Richardson, M; Mendis, P; Ebeling, P 2017-09-01 The role of impairment of mesenchymal stem cell function in osteoporotic bone fracture healing With demographic change and increasing life expectancy, osteoporotic fractures have become one of the most prevalent trauma conditions seen in daily clinical practice. A variety of factors are known to affect the rate of healing in osteoporotic conditions (e.g. both biochemical and biomechanical environment of callus cells). However, the influence of impairment of mesenchymal stem cell function in the osteoporotic condition on bone fracture healing has not been fully understood. In the present study, we develop a mathematical model that quantifies the change in biological processes within the fracture callus as a result of osteoporosis. The model includes special features of osteoporosis such as reduction in mesenchymal stem cell (MSC) number in osteoporotic bone, impaired response of osteoporotic MSCs to their biomechanical microenvironment and the effects of configuration of locking compression plate (LCP) system on healing in this context. The results presented here suggest that mechanically-mediated MSCs differentiation at early stages of healing are significantly affected under osteoporotic conditions, while it is predicted that the flexible fixation achieved by increasing bone-plate distance of LCP could alleviate the negative effects of osteoporosis on healing. The outcomes of this study could potentially lead to patient specific surgical solutions, and thus achieve optimal healing outcomes in osteoporotic conditions. Journal Article

e Analysis of Platelet-Rich Plasma Extraction Variations in Platelet and Blood Components Between 4 Common Commercial Kits

2020-11-26T12:39:52Z

Fitzpatrick, J; Bulsara, MK; McCrory, PR; Richardson, MD; Zheng, MH 2017-01-01 e Analysis of Platelet-Rich Plasma Extraction Variations in Platelet and Blood Components Between 4 Common Commercial Kits BACKGROUND: Platelet-rich plasma (PRP) has been extensively used as a treatment in tissue healing in tendinopathy, muscle injury, and osteoarthritis. However, there is variation in methods of extraction, and this produces different types of PRP. PURPOSE: To determine the composition of PRP obtained from 4 commercial separation kits, which would allow assessment of current classification systems used in cross-study comparisons. STUDY DESIGN: Controlled laboratory study. METHODS: Three normal adults each donated 181 mL of whole blood, some of which served as a control and the remainder of which was processed through 4 PRP separation kits: GPS III (Biomet Biologics), Smart-Prep2 (Harvest Terumo), Magellan (Arteriocyte Medical Systems), and ACP (Device Technologies). The resultant PRP was tested for platelet count, red blood cell count, and white blood cell count, including differential in a commercial pathology laboratory. Glucose and pH measurements were obtained from a blood gas autoanalyzer machine. RESULTS: Three kits taking samples from the "buffy coat layer" were found to have greater concentrations of platelets (3-6 times baseline), while 1 kit taking samples from plasma was found to have platelet concentrations of only 1.5 times baseline. The same 3 kits produced an increased concentration of white blood cells (3-6 times baseline); these consisted of neutrophils, leukocytes, and monocytes. This represents high concentrations of platelets and white blood cells. A small drop in pH was thought to relate to the citrate used in the sample preparation. Interestingly, an unexpected increase in glucose concentrations, with 3 to 6 times greater than baseline levels, was found in all samples. CONCLUSION: This study reveals the variation of blood components, including platelets, red blood cells, leukocytes, pH, and glucose in PRP extractions. The high concentrations of cells are important, as the white blood cell count in PRP samples has frequently been ignored, being considered insignificant. The lack of standardization of PRP preparation for clinical use has contributed at least in part to the varying clinical efficacy in PRP use. CLINICAL RELEVANCE: The variation of platelet and other blood component concentrations between commercial PRP kits may affect clinical treatment outcomes. There is a need for standardization of PRP for clinical use. Journal Article

A good resource for parents, but will clinicians use it?: Evaluation of a resource for paediatric end-of-life decision making

2020-11-26T12:39:52Z

Delany, C; Xafis, V; Gillam, L; Hughson, J-A; Hynson, J; Wilkinson, D 2017-01-25 A good resource for parents, but will clinicians use it?: Evaluation of a resource for paediatric end-of-life decision making BACKGROUND: Communication with parents about end-of-life care and decisions is a difficult and sensitive process. The objective of the present study was to ascertain clinicians' views on the acceptability and usefulness of a handbook and web-based resource (Caring Decisions) that was designed as an aid for parents facing end-of-life decisions for their child. METHODS: Qualitative interviews were conducted with a range of health professionals who provide care to children facing life-limiting conditions. RESULTS: Data analysis confirmed the acceptability and usefulness of the resource. Two major themes were revealed: 1. Family empowerment, with sub-themes Giving words and clarity, Conversation starter, 'I'm not alone in this', and A resource to take away, highlighted how the resource filled a gap by supporting and enabling families in a multitude of ways; 2. Not just for families, with sub-themes A guide for staff, When to give the resource?, How to give the resource and Who should give the resource?, explored the significant finding that participants viewed the resource as a valuable tool for themselves, but its presence also brought into relief potential gaps in communication processes around end-of-life care. CONCLUSION: The interview data indicated the positive reception and clear value and need for this type of resource. However, it is likely that successful resource uptake will be contingent on discussion and planning around dissemination and use within the health care team. Journal Article

Undernutrition and malaria in pregnancy - a dangerous dyad?

2020-11-26T12:39:52Z

Unger, HW; Ashorn, P; Cates, JE; Dewey, KG; Rogerson, SJ 2016-09-19 Undernutrition and malaria in pregnancy - a dangerous dyad? BACKGROUND: In low-resource settings, malaria and macronutrient undernutrition are major health problems in pregnancy, contributing significantly to adverse pregnancy outcomes such as preterm birth and fetal growth restriction. Affected pregnancies may result in stillbirth and neonatal death, and surviving children are at risk of poor growth and infection in infancy, and of non-communicable diseases in adulthood. Populations exposed to macronutrient undernutrition frequently reside in malaria-endemic areas, and seasonal peaks of low food supply and malaria transmission tend to coincide. Despite these geographic and temporal overlaps, integrated approaches to these twin challenges are infrequent. DISCUSSION: This opinion article examines the current evidence for malaria-macronutrition interactions and discusses possible mechanisms whereby macronutrient undernutrition and malaria may interact to worsen pregnancy outcomes. Macronutrient undernutrition dysregulates the immune response. In pregnant women, undernutrition may worsen the already increased susceptibility to malarial infection and could impair development of protective immunity to malaria, and is likely to exacerbate the impact of placental malaria on fetal growth. Malarial infection, in turn, can drive nutritional depletion; poor gestational weight gain and weight loss in pregnancy increases the risk of adverse pregnancy outcomes. Despite a commendable number of studies and trials that, in isolation, attempt to address the challenges of malaria and undernutrition in pregnancy, few dare to venture beyond the 'single disease - single solution' paradigm. We believe that this may be a lost opportunity: researching malaria-nutrition interactions, and designing and implementing integrated interventions to prevent and treat these commonly co-existing and intertwining conditions, may markedly reduce the high burden of preterm birth and fetal growth restriction in affected areas. CONCLUSION: We call for more collaboration between researchers studying malaria and nutrition in pregnancy, and propose a research agenda to address this important twin health problem. Journal Article

Quantitative Analysis of the Ellipsoid Zone Intensity in Phenotypic Variations of Intermediate Age-Related Macular Degeneration

2020-11-26T12:39:52Z

Gin, TJ; Wu, Z; Chew, SKH; Guymer, RH; Luu, CD 2017-04-01 Quantitative Analysis of the Ellipsoid Zone Intensity in Phenotypic Variations of Intermediate Age-Related Macular Degeneration Purpose: Reduction of the ellipsoid zone (EZ) intensity has been reported in eyes with age-related macular degeneration (AMD). This study determined whether overall EZ intensity, in retinal locations undisturbed by pathologic features, is associated with the presence of clinical features, which are known important phenotypic risk factors for disease progression, large drusen, reticular pseudodrusen (RPD), and pigmentary abnormalities. Methods: A horizontal B-scan through the foveola on spectral-domain optical coherence tomography (SD-OCT) was performed in both eyes of 75 participants with bilateral intermediate AMD and 10 age-similar control participants. Eyes with AMD were classified as per the presence of large drusen, RPD, and hyperpigmentary changes. The relative EZ intensity profile, up to an eccentricity of 3400 μm, was averaged over seven 1000-μm retinal segments. The association between relative EZ intensity profile over seven retinal segments and AMD pathologic features was analyzed. Results: The average relative EZ intensities were significantly reduced in eyes with intermediate AMD compared to normal eyes (P ≤ 0.025) and with increasing age (P ≤ 0.020). On multivariate analyses, only the presence of hyperpigmentary changes and increasing age were significantly associated with reduced overall relative intensities (P ≤ 0.024), but not the presence of large drusen or RPD (P ≥ 0.115). Conclusions: The presence of hyperpigmentary change in the macula in association with large drusen, not large drusen alone, nor large drusen with RPD, was significantly associated with a generalised reduction in EZ intensity. Quantitative assessment of the relative EZ intensity may serve as an effective biomarker of disease severity and progression. Journal Article

A Tablet-Based Retinal Function Test in Neovascular Age-Related Macular Degeneration Eyes and At-Risk Fellow Eye

2020-11-26T12:39:52Z

Ho, CYD; Wu, Z; Turpin, A; Lawson, DJ; Luu, CD; McKendrick, AM; Guymer, RH 2018-03-01 A Tablet-Based Retinal Function Test in Neovascular Age-Related Macular Degeneration Eyes and At-Risk Fellow Eye Purpose: To determine the feasibility of a tablet-based application to detect changes in retinal sensitivity and correlations with underlying pathology in neovascular age-related macular degeneration (nAMD) eyes undergoing treatment and in at-risk fellow eyes. Method: Participants with nAMD in at least one eye were recruited, examined, and imaged using spectral-domain optical coherence tomography (SD-OCT). Retinal sensitivity was measured within the central 5° at 12 locations using a customized test delivered on an iPad. Test points were superimposed on SD-OCT locations to investigate structure/function relationships. Results: Included in the study were 53 nAMD eyes and 21 at-risk fellow eyes. In nAMD eyes, the mean retinal sensitivity was 24.1 ± 1.8 dB with reduced retinal sensitivity associated with the presence of atrophy (P < 0.01), retinal pigment epithelium (RPE) disruption (P < 0.01), and absent ellipsoid zone (EZ) (P < 0.01), but not with the presence of subretinal fluid (P = 0.94) nor intraretinal fluid (P = 0.52). In at-risk eyes, the average retinal sensitivity was 28.8 ± 0.6 dB, with reduced sensitivity significantly associated with the presence of drusen, atrophy, RPE disruption, and absent EZ (P < 0.01). Conclusion: The tablet-based test of retinal sensitivity was able to be performed by an elderly cohort with nAMD. The ability to correlate differences in sensitivity with pathology is encouraging when considering using the tablet devices as a home monitoring tool with remote surveillance. Dual pathology often present with retinal fluid confounded our ability to correlate fluid with sensitivity. Translational Relevance: These findings highlight the potential of tablet-based devices in performing visual function measures as a home monitoring tool with remote surveillance for the earlier detection of nAMD. Journal Article

The relationship between interfragmentary movement and cell differentiation in early fracture healing under locking plate fixation

2020-11-26T12:39:52Z

Miramini, S; Zhang, L; Richardson, M; Mendis, P; Oloyede, A; Ebeling, P 2016 The relationship between interfragmentary movement and cell differentiation in early fracture healing under locking plate fixation Interfragmentary movement (IFM) at the fracture site plays an important role in fracture healing, particularly during its early stage, via influencing the mechanical microenvironment of mesenchymal stem cells within the fracture callus. However, the effect of changes in IFM resulting from the changes in the configuration of locking plate fixation on cell differentiation has not yet been fully understood. In this study, mechanical experiments on surrogate tibia specimens, manufactured from specially formulated polyurethane, were conducted to investigate changes in IFM of fractures under various locking plate fixation configurations and loading magnitudes. The effect of the observed IFM on callus cell differentiation was then further studied using computational simulation. We found that during the early stage, cell differentiation in the fracture callus is highly influenced by fracture gap size and IFM, which in turn, is highly sensitive to locking plate fixation configuration. The computational model predicted that a small gap size (e.g. 1 mm) under a relatively flexible configuration of locking plate fixation (larger bone-plate distances and working lengths) could experience excessive strain and fluid flow within the fracture site, resulting in excessive fibrous tissue differentiation and delayed healing. By contrast, a relatively flexible configuration of locking plate fixation was predicted to improve cartilaginous callus formation and bone healing for a relatively larger gap size (e.g. 3 mm). If further confirmed by animal and human studies, the research outcome of this paper may have implications for orthopaedic surgeons in optimising the application of locking plate fixations for fractures in clinical practice. Journal Article