Medicine, Dentistry & Health Sciences Collected Works - Research Publications
Now showing items 1-12 of 578
Cross-Study Comparison Reveals Common Genomic, Network, and Functional Signatures of Desiccation Resistance in Drosophila melanogaster
(OXFORD UNIV PRESS, 2016-04-01)
Repeated attempts to map the genomic basis of complex traits often yield different outcomes because of the influence of genetic background, gene-by-environment interactions, and/or statistical limitations. However, where repeatability is low at the level of individual genes, overlap often occurs in gene ontology categories, genetic pathways, and interaction networks. Here we report on the genomic overlap for natural desiccation resistance from a Pool-genome-wide association study experiment and a selection experiment in flies collected from the same region in southeastern Australia in different years. We identified over 600 single nucleotide polymorphisms associated with desiccation resistance in flies derived from almost 1,000 wild-caught genotypes, a similar number of loci to that observed in our previous genomic study of selected lines, demonstrating the genetic complexity of this ecologically important trait. By harnessing the power of cross-study comparison, we narrowed the candidates from almost 400 genes in each study to a core set of 45 genes, enriched for stimulus, stress, and defense responses. In addition to gene-level overlap, there was higher order congruence at the network and functional levels, suggesting genetic redundancy in key stress sensing, stress response, immunity, signaling, and gene expression pathways. We also identified variants linked to different molecular aspects of desiccation physiology previously verified from functional experiments. Our approach provides insight into the genomic basis of a complex and ecologically important trait and predicts candidate genetic pathways to explore in multiple genetic backgrounds and related species within a functional framework.
Nationwide Survey of Knowledge and Health Beliefs regarding Human Papillomavirus among HPV-Vaccinated Female Students in Malaysia
(PUBLIC LIBRARY SCIENCE, 2016-09-22)
The National HPV Immunization Programme, which offers free human papillomavirus (HPV) vaccines to teenaged female students, was launched in Malaysia in 2010. HPV vaccination paired with adequate knowledge about HPV infection provides the best protection against cervical cancer. To identify the level of knowledge and the health beliefs towards HPV and the HPV vaccine among HPV-vaccinated female students in Malaysia. A nationwide cross-sectional survey among 14 years old female students who had received three doses of the HPV vaccine was conducted in 32 randomly selected schools from 13 states and 3 federal territories in Malaysia between February 2013 and April 2013. Among 2482 respondents, knowledge about HPV infection and the HPV vaccine was extremely poor. The mean total knowledge score was only 3.56 (SD ± 1.76), out of a possible score of 10. The majority of respondents were unaware that vaccinating boys with HPV can help protect girls against HPV infection (91.6%), HPV cannot be cured (81.6%) and that HPV is a sexually transmitted infection (70.3%). Most of the respondents had the misconception that only females get HPV (95.1%), and that the HPV vaccine eliminates the need for Pap smear tests (68.3%). Most respondents (91.6%) believed that they would not get an HPV infection. Almost half of the respondents (42.9%) held the misconception that HPV infection could not lead to serious illness. Findings revealed poor knowledge about both HPV and the HPV vaccine, low perceived susceptibility to HPV infection and misinformation about HPV infection among HPV-vaccinated girls. Therefore, it is essential to increase the knowledge and awareness of health risks regarding HPV infection among teenaged girls who have received the HPV vaccine.
Most prevalent unmet supportive care needs and quality of life of breast cancer patients in a tertiary hospital in Malaysia
BACKGROUND: Addressing breast cancer patients' unmet supportive care needs in the early stage of their survivorship have become a prime concern because of its significant association with poor quality of life (QOL), which in turn increases healthcare utilization and costs. There is no study about unmet supportive care needs of breast cancer patients in Malaysia. This study aims to assess the most prevalent unmet supportive care needs of Malaysian breast cancer patients and the association between QOL and patients' characteristics, and their unmet supportive care needs. METHODS: A cross-sectional study was conducted at the Surgery and Oncology Clinic between May 2014 and June 2014 in a tertiary hospital in Malaysia. A total of 117 patients out of 133 breast cancer patients recruited by universal sampling were interviewed using a structured questionnaire consisted of three parts: participants' socio-demographic and disease characteristics, Supportive Care Needs Survey-Short Form Questionnaire (SCNS-SF34) and European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C30 (EORTC QLQ-C30). RESULTS: The highest unmet supportive care needs were observed in the psychological domain (Mean 53.31; SD ± 21.79), followed by physical domain (Mean 38.16; SD ± 27.15). Most prevalent unmet supportive care needs were uncertainty about the future (78.6 %), fears about the cancer spreading (76.1 %), feelings of sadness (69.2 %), feelings about death and dying (68.4 %), concerns about those close to the patient (65.0 %) and feeling down or depressed (65.0 %). Multivariate linear analysis showed that early breast cancer survivors diagnosed at an advanced stage and with greater physical and psychological needs were significantly (p < 0.05) associated with poorer QOL. CONCLUSION: Most prevalent unmet needs among Malaysian breast cancer patients were found in the psychological domain. Early breast cancer survivors with late stage diagnosis who had more unmet needs in psychological and physical domains were more likely to have a poor QOL.
A case of chronic inflammatory demyelinating polyneuropathy with reversible alternating diaphragmatic paralysis: case study
Respiratory failure requiring mechanical ventilation has been reported in patients with bilateral diaphragmatic paralysis due to CIDP. We report a case of CIDP that progressed to respiratory failure with normal chest radiography despite unilateral diaphragmatic paralysis. This manifestation would have been missed if ultrasound was not employed.
Effect of chronic antipsychotic treatment on striatal phosphodiesterase 10A levels: a [(11C)]MP-10 PET rodent imaging study with ex vivo confirmation
(NATURE PUBLISHING GROUP, 2014-04-01)
A number of phosphodiesterase 10A (PDE10) inhibitors are about to undergo clinical evaluation for their efficacy in treating schizophrenia. As phosphodiesterases are in the same signalling pathway as dopamine D2 receptors, it is possible that prior antipsychotic treatment could influence these enzyme systems in patients. Chronic, in contrast to acute, antipsychotic treatment has been reported to increase brain PDE10A levels in rodents. The aim of this study was to confirm these findings in a manner that can be translated to human imaging studies to understand its consequences. Positron emission tomography (PET) scanning was used to evaluate PDE10A enzyme availability, after chronic haloperidol administration, using a specific PDE10A ligand ([(11)C]MP-10). The binding of [(11)C]MP-10 in the striatum and the cerebellum was measured in rodents and a simplified reference tissue model (SRTM) with cerebellum as the reference region was used to determine the binding potential (BPND). In rats treated chronically with haloperidol (2 mg kg(-1) per day), there was no significant difference in PDE10A levels compared with the vehicle-treated group (BPND±s.d.: 3.57 ± 0.64 versus 2.86 ± 0.71). Following PET scans, ex vivo analysis of striatal brain tissue for PDE10A mRNA (Pde10a) and PDE10A enzyme activity showed no significant difference. Similarly, the PDE10A protein content determined by western blot analysis was similar between the two groups, contrary to an earlier finding. The results of the study indicate that prior exposure to antipsychotic medication in rodents does not alter PDE10A levels.
Haloperidol and olanzapine mediate metabolic abnormalities through different molecular pathways
(NATURE PUBLISHING GROUP, 2013-01-01)
The pathogenesis of antipsychotic-induced disturbances of glucose homeostasis is still unclear. Increased visceral adiposity has been suggested to be a possible mediating mechanism. The aim of this study was to investigate, in an animal model, the differential effects of olanzapine and haloperidol on visceral fat deposition (using magnetic resonance imaging(MRI)) and on critical nodes of the insulin signaling pathway (liver-protein levels of IRS2 (insulin receptor substrate 2), GSK3α (glycogen synthase kinase-3α), GSK3β, GSK3α-Ser21, GSK3β-Ser9). To this end, we studied male Sprague-Dawley rats treated with vehicle (n=8), haloperidol (2 mg kg(-1) per day, n=8), or olanzapine (10 mg kg(-1)per day, n=8), using osmotic minipumps, for 8 weeks. The haloperidol group showed a higher percentage of visceral fat than both the olanzapine group and the vehicle group, whereas there was no difference between the olanzapine and the vehicle group. In terms of insulin signaling pathway, the olanzapine group showed significantly reduced IRS2 levels, reduced phosphorylation of GSK3α and increased phosphorylation of GSK3β, whereas there was no difference between the haloperidol and the vehicle group. Our data suggest that different molecular pathways mediate the disturbances of glucose homeostasis induced by haloperidol and olanzapine with a direct effect of olanzapine on the insulin molecular pathway, possibly partly explaining the stronger propensity of olanzapine for adverse effects on glucose regulation when compared with haloperidol in clinical settings.
Integrating mobile-phone based assessment for psychosis into people's everyday lives and clinical care: a qualitative study
BACKGROUND: Over the past decade policy makers have emphasised the importance of healthcare technology in the management of long-term conditions. Mobile-phone based assessment may be one method of facilitating clinically- and cost-effective intervention, and increasing the autonomy and independence of service users. Recently, text-message and smartphone interfaces have been developed for the real-time assessment of symptoms in individuals with schizophrenia. Little is currently understood about patients' perceptions of these systems, and how they might be implemented into their everyday routine and clinical care. METHOD: 24 community based individuals with non-affective psychosis completed a randomised repeated-measure cross-over design study, where they filled in self-report questions about their symptoms via text-messages on their own phone, or via a purpose designed software application for Android smartphones, for six days. Qualitative interviews were conducted in order to explore participants' perceptions and experiences of the devices, and thematic analysis was used to analyse the data. RESULTS: Three themes emerged from the data: i) the appeal of usability and familiarity, ii) acceptability, validity and integration into domestic routines, and iii) perceived impact on clinical care. Although participants generally found the technology non-stigmatising and well integrated into their everyday activities, the repetitiveness of the questions was identified as a likely barrier to long-term adoption. Potential benefits to the quality of care received were seen in terms of assisting clinicians, faster and more efficient data exchange, and aiding patient-clinician communication. However, patients often failed to see the relevance of the systems to their personal situations, and emphasised the threat to the person centred element of their care. CONCLUSIONS: The feedback presented in this paper suggests that patients are conscious of the benefits that mobile-phone based assessment could bring to clinical care, and that the technology can be successfully integrated into everyday routine. However, it also suggests that it is important to demonstrate to patients the personal, as well as theoretical, benefits of the technology. In the future it will be important to establish whether clinical practitioners are able to use this technology as part of a personalised mental health regime.
Chronic exposure to haloperidol and olanzapine leads to common and divergent shape changes in the rat hippocampus in the absence of grey-matter volume loss
(CAMBRIDGE UNIV PRESS, 2016-11-01)
BACKGROUND: One of the most consistently reported brain abnormalities in schizophrenia (SCZ) is decreased volume and shape deformation of the hippocampus. However, the potential contribution of chronic antipsychotic medication exposure to these phenomena remains unclear. METHOD: We examined the effect of chronic exposure (8 weeks) to clinically relevant doses of either haloperidol (HAL) or olanzapine (OLZ) on adult rat hippocampal volume and shape using ex vivo structural MRI with the brain retained inside the cranium to prevent distortions due to dissection, followed by tensor-based morphometry (TBM) and elastic surface-based shape deformation analysis. The volume of the hippocampus was also measured post-mortem from brain tissue sections in each group. RESULTS: Chronic exposure to either HAL or OLZ had no effect on the volume of the hippocampus, even at exploratory thresholds, which was confirmed post-mortem. In contrast, shape deformation analysis revealed that chronic HAL and OLZ exposure lead to both common and divergent shape deformations (q = 0.05, FDR-corrected) in the rat hippocampus. In particular, in the dorsal hippocampus, HAL exposure led to inward shape deformation, whereas OLZ exposure led to outward shape deformation. Interestingly, outward shape deformations that were common to both drugs occurred in the ventral hippocampus. These effects remained significant after controlling for hippocampal volume suggesting true shape changes. CONCLUSIONS: Chronic exposure to either HAL or OLZ leads to both common and divergent effects on rat hippocampal shape in the absence of volume change. The implications of these findings for the clinic are discussed.
Sensorimotor gating, cannabis use and the risk of psychosis
(ELSEVIER SCIENCE BV, 2015-05-01)
Sensorimotor gating, measured as the modification of eye blink startle reflexes to loud acoustic stimuli by quieter preceding stimuli, is altered in those with psychosis, their relatives and those at high clinical risk for psychosis. Alterations have also been shown in cannabis users, albeit to a lesser extent, and cannabis is a known risk factor for the onset of psychosis in clinically and genetically susceptible individuals. We examined the interaction between clinical risk for psychosis and cannabis use on sensorimotor gating, both Prepulse Inhibition (PPI) and Prepulse Facilitation (PPF). We tested PPI and PPF in participants with an At Risk Mental State (ARMS) for psychosis and a matched control group. Both groups included a proportion of subjects who had recently used cannabis, as confirmed by urinary drug screening (UDS) on the day of testing. We found that ARMS participants showed reduced PPF and PPI relative to controls, the latter driven by a group by cannabis use interaction, with recent use reducing PPI in ARMS participants but not in controls. When the analysis was limited to UDS-negative participants there was significantly reduced PPF in ARMS subjects relative to controls, but no differences in PPI. Within the ARMS group reduced sensorimotor gating, measured by both PPI and PPF, related to reduced overall level of function. Cannabis use in clinical high risk individuals may increase the risk of psychosis in part through worsening PPI, while PPF is altered in ARMS individuals irrespective of cannabis use. This develops our understanding of cognitive mechanisms leading to the experience of aberrant perceptual phenomena and the subsequent development of psychotic symptoms.
The feasibility and validity of ambulatory self-report of psychotic symptoms using a smartphone software application
(BIOMED CENTRAL LTD, 2012-10-17)
BACKGROUND: Semi-structured interview scales for psychosis are the gold standard approach to assessing psychotic and other symptoms. However, such assessments have limitations such as recall bias, averaging, insensitivity to change and variable interrater reliability. Ambulant, real-time self-report assessment devices may hold advantages over interview measures, but it needs to be shown that the data thus collected are valid, and the collection method is acceptable, feasible and safe. We report on a monitoring system for the assessment of psychosis using smartphone technology. The primary aims were to: i) assess validity through correlations of item responses with those on widely accepted interview assessments of psychosis, and ii) examine compliance to the procedure in individuals with psychosis of varying severity. METHODS: A total of 44 participants (acute or remitted DSM-4 schizophrenia and related disorders, and prodromal) completed 14 branching self-report items concerning key psychotic symptoms on a touch-screen mobile phone when prompted by an alarm at six pseudo-random times, each day, for one week. Face to face PANSS and CDS interviews were conducted before and after the assessment period blind to the ambulant data. RESULTS: Compliance as defined by completion of at least 33% of all possible data-points over seven days was 82%. In the 36 compliant participants, 5 items (delusions, hallucinations, suspiciousness, anxiety, hopelessness) showed moderate to strong (rho 0.6-0.8) associations with corresponding items from interview rating scales. Four items showed no significant correlation with rating scales: each was an item based on observable behaviour. Ambulant ratings showed excellent test-retest reliability and sensitivity to change. CONCLUSIONS: Ambulatory monitoring of symptoms several times daily using smartphone software applications represents a feasible and valid way of assessing psychotic phenomena for research and clinical management purposes. Further evaluation required over longer assessment periods, in clinical trials and service settings.
Epistatic interactions between mutations of TACI (TNFRSF13B) and TCF3 result in a severe primary immunodeficiency disorder and systemic lupus erythematosus
Common variable immunodeficiency disorders (CVID) are a group of primary immunodeficiencies where monogenetic causes account for only a fraction of cases. On this evidence, CVID is potentially polygenic and epistatic although there are, as yet, no examples to support this hypothesis. We have identified a non-consanguineous family, who carry the C104R (c.310T>C) mutation of the Transmembrane Activator Calcium-modulator and cyclophilin ligand Interactor (TACI, TNFRSF13B) gene. Variants in TNFRSF13B/TACI are identified in up to 10% of CVID patients, and are associated with, but not solely causative of CVID. The proband is heterozygous for the TNFRSF13B/TACI C104R mutation and meets the Ameratunga et al. diagnostic criteria for CVID and the American College of Rheumatology criteria for systemic lupus erythematosus (SLE). Her son has type 1 diabetes, arthritis, reduced IgG levels and IgA deficiency, but has not inherited the TNFRSF13B/TACI mutation. Her brother, homozygous for the TNFRSF13B/TACI mutation, is in good health despite profound hypogammaglobulinemia and mild cytopenias. We hypothesised that a second unidentified mutation contributed to the symptomatic phenotype of the proband and her son. Whole-exome sequencing of the family revealed a de novo nonsense mutation (T168fsX191) in the Transcription Factor 3 (TCF3) gene encoding the E2A transcription factors, present only in the proband and her son. We demonstrate mutations of TNFRSF13B/TACI impair immunoglobulin isotype switching and antibody production predominantly via T-cell-independent signalling, while mutations of TCF3 impair both T-cell-dependent and -independent pathways of B-cell activation and differentiation. We conclude that epistatic interactions between mutations of the TNFRSF13B/TACI and TCF3 signalling networks lead to the severe CVID-like disorder and SLE in the proband.
The heterogeneity of antipsychotic response in the treatment of schizophrenia
(CAMBRIDGE UNIV PRESS, 2011-06-01)
BACKGROUND: Schizophrenia is a heterogeneous disorder in terms of patient response to antipsychotic treatment. Understanding the heterogeneity of treatment response may help to guide treatment decisions. This study was undertaken to capture inherent patterns of response to antipsychotic treatment in patients with schizophrenia, characterize the subgroups of patients with similar courses of response, and examine illness characteristics at baseline as possible predictors of response. METHOD: Growth mixture modeling (GMM) was applied to data from a randomized, double-blind, 12-week study of 628 patients with schizophrenia or schizo-affective disorder treated with risperidone or olanzapine. RESULTS: Four distinct response trajectories based on Positive and Negative Syndrome Scale (PANSS) total score over 12 weeks were identified: Class 1 (420 patients, 80.6%) with moderate average baseline PANSS total score showing gradual symptom improvement; Class 2 (65 patients, 12.5%) showing rapid symptom improvement; Class 3 (24 patients, 4.6%) with high average baseline PANSS total score showing gradual symptom improvement; and Class 4 (12 patients, 2.3%) showing unsustained symptom improvement. Latent class membership of early responders (ER) and early non-responders (ENR) was determined based on 20% symptom improvement criteria at 2 weeks and ultimate responders (UR) and ultimate non-responders (UNR) based on 40% symptom improvement criteria at 12 weeks. Baseline factors with potential influence on latent class membership were identified. CONCLUSIONS: This study identified four distinct treatment response patterns with predominant representation of responders or non-responders to treatment in these classes. This heterogeneity may represent discrete endophenotypes of response to treatment with different etiologic underpinnings.