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result(s) for
"Ch’ng, Sarah S."
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Cocaine and amphetamine regulated transcript (CART) mediates sex differences in binge drinking through central taste circuits
2024
The neuropeptide cocaine- and amphetamine-regulated transcript (CART) has been implicated in alcohol consumption and reward behaviours, yet mechanisms mediating these effects have yet to be identified. Using a transgenic CART knockout (KO) mouse line we uncovered a sexually dimorphic effect of CART in binge drinking, with male CART KO mice increasing intake, whilst female CART KO mice decreased their alcohol intake compared to controls. Female CART KO mice show greater sensitivity to bitter solutions that can be overshadowed through addition of a sweetener, implicating taste as a factor. Further we identify that this is not driven through peripherally circulating sex hormones, but the central nucleus of the amygdala (CeA) is a locus where CART contributes to the regulation of alcohol consumption, with CeA CART neutralisation specifically reducing plain alcohol, but not sweetened alcohol consumption in female mice. These findings may have implications for the development of sex-specific treatment options for alcohol use disorders through targeting the CART system.
Journal Article
A paraventricular thalamus to insular cortex glutamatergic projection gates “emotional” stress-induced binge eating in females
by
G. Anversa, Roberta
,
Brown, Robyn M
,
Dayas, Christopher V
in
Anatomy
,
Binge eating
,
Brain architecture
2023
It is well-established that stress and negative affect trigger eating disorder symptoms and that the brains of men and women respond to stress in different ways. Indeed, women suffer disproportionately from emotional or stress-related eating, as well as associated eating disorders such as binge eating disorder. Nevertheless, our understanding of the precise neural circuits driving this maladaptive eating behavior, particularly in women, remains limited. We recently established a clinically relevant model of ‘emotional’ stress-induced binge eating whereby only female mice display binge eating in response to an acute “emotional” stressor. Here, we combined neuroanatomic, transgenic, immunohistochemical and pathway-specific chemogenetic approaches to investigate whole brain functional architecture associated with stress-induced binge eating in females, focusing on the role of Vglut2 projections from the paraventricular thalamus (PVTVglut2+) to the medial insular cortex in this behavior. Whole brain activation mapping and hierarchical clustering of Euclidean distances revealed distinct patterns of coactivation unique to stress-induced binge eating. At a pathway-specific level, PVTVglut2+ cells projecting to the medial insular cortex were specifically activated in response to stress-induced binge eating. Subsequent chemogenetic inhibition of this pathway suppressed stress-induced binge eating. We have identified a distinct PVTVglut2+ to insular cortex projection as a key driver of “emotional” stress-induced binge eating in female mice, highlighting a novel circuit underpinning this sex-specific behavior.
Journal Article
Differential Level of RXFP3 Expression in Dopaminergic Neurons Within the Arcuate Nucleus, Dorsomedial Hypothalamus and Ventral Tegmental Area of RXFP3-Cre/tdTomato Mice
by
Gray, Laura
,
Williams, Richard
,
Gundlach, Andrew L.
in
Antibodies
,
Arcuate nucleus
,
Brain research
2021
RXFP3 (relaxin-family peptide 3 receptor) is the cognate G-protein-coupled receptor for the neuropeptide, relaxin-3. RXFP3 is expressed widely throughout the brain, including the hypothalamus, where it has been shown to modulate feeding behavior and neuroendocrine activity in rodents. In order to better characterize its potential mechanisms of action, this study determined whether RXFP3 is expressed by dopaminergic neurons within the arcuate nucleus (ARC) and dorsomedial hypothalamus (DMH), in addition to the ventral tegmental area (VTA). Neurons that express RXFP3 were visualized in coronal brain sections from RXFP3-Cre/tdTomato mice, which express the tdTomato fluorophore within RXFP3-positive cells, and dopaminergic neurons in these areas were visualized by simultaneous immunohistochemical detection of tyrosine hydroxylase-immunoreactivity (TH-IR). Approximately 20% of ARC neurons containing TH-IR coexpressed tdTomato fluorescence, suggesting that RXFP3 can influence the dopamine pathway from the ARC to the pituitary gland that controls prolactin release. The ability of prolactin to reduce leptin sensitivity and increase food consumption therefore represents a potential mechanism by which RXFP3 activation influences feeding. A similar proportion of DMH neurons containing TH-IR expressed RXFP3-related tdTomato fluorescence, consistent with a possible RXFP3-mediated regulation of stress and neuroendocrine circuits. In contrast, RXFP3 was barely detected within the VTA. TdTomato signal was absent from the ARC and DMH in sections from Rosa26-tdTomato mice, suggesting that the cells identified in RXFP3-Cre/tdTomato mice expressed authentic RXFP3-related tdTomato fluorescence. Together, these findings identify potential hypothalamic mechanisms through which RXFP3 influences neuroendocrine control of metabolism, and further highlight the therapeutic potential of targeting RXFP3 in feeding-related disorders.
Journal Article
The Impact of Removal of Ovarian Hormones on Cholinergic Muscarinic Receptors: Examining Prepulse Inhibition and Receptor Binding
2020
Ovarian hormones, such as estrogens and progesterone, are known to exert beneficial effects on cognition and some psychiatric disorders. The basis of these effects is not fully understood, but may involve altered cholinergic neurotransmission. This study aimed to investigate how a lack of ovarian hormones would impact muscarinic receptor-induced deficits in prepulse inhibition (PPI) and muscarinic receptor density in several brain regions. Adult female rats were either ovariectomized, to remove the source of ovarian hormones, or left intact (sham-operated). PPI is a measure of sensorimotor gating that is typically impaired in schizophrenia patients, and similar deficits can be induced in rats by administering scopolamine, a muscarinic receptor antagonist. Our results revealed no significant effects of ovariectomy on PPI after saline or scopolamine treatment. Autoradiography was performed to measure cholinergic muscarinic receptor binding density using [3H]-pirenzepine, [3H]-AF-DX, and [3H]-4-DAMP, to label M1, M2/M4, and M3 receptors, respectively. We examined the amygdala, caudate putamen, dorsal hippocampus, motor cortex, retrosplenial cortex, and ventromedial hypothalamus. There were no significant group differences in any region for any muscarinic receptor type. These results suggest that removing peripheral ovarian hormones does not influence the cholinergic muscarinic receptor system in the context of PPI or receptor binding density.
Journal Article
Highly replicating hepatitis C virus variants emerge in immunosuppressed patients causing severe disease
by
Förster, Colin
,
Mogler, Carolin
,
Wang, Zhiqing
in
Carcinoma, Hepatocellular - virology
,
Cell culture
,
Clinical isolates
2025
Hepatitis C virus (HCV) exists as a heterogenous quasispecies, but the phenotypic consequences of viral variability are widely unexplored. Here we identify a replication enhancing domain (ReED) in non-structural protein 5A conferring high replication fitness to clinical isolates. Accumulation of mutations in the ReED mediates high genome replication capacity. In a cohort of liver transplant patients, high replicator variants are exclusively found in individuals with severe disease outcome, suggesting that high viral replication fitness is associated with increased viral pathogenesis. Analysis of large sequence cohorts reveals that overall only 10% of viral genomes show genetic signatures of high replicators, which are enriched in recipients of liver transplantations, patients developing hepatocellular carcinoma and in HIV coinfected individuals. Overall, our data suggests that low replication fitness is a hallmark of HCV, contributing to establishment of persistence, whereas high replicators appear to have an advantage under conditions of immune suppression, thereby enforcing pathogenesis.
Journal Article
Sentinel Node Biopsy in 105 High-Risk Cutaneous SCCs of the Head and Neck: Results of a Multicenter Prospective Study
2019
Background
Regional nodal metastases from cutaneous squamous cell carcinoma (cSCC) is strongly associated with a poor prognosis, but these metastases are difficult to predict clinically. Sentinel node biopsy (SNB) has been used for a wide range of malignancies to assess for regional nodal metastasis, but is not widely used for cSCC.
Methods
Patients presenting with high-risk cSCC of the head and neck with clinically N0 necks were offered SNB at the time of primary cSCC excision or secondary wide local excision. Patients with positive sentinel nodes were offered completion lymph node dissection, and all the patients were followed up at regular intervals for up to 5 years.
Results
In this study, 105 lesions underwent SNB, and 10 sentinel nodes (9.5%) were positive. In an additional five patients, regional recurrence developed after a negative sentinel node, with a total subclinical nodal metastasis rate of 14.3%. Nodal metastases were significantly associated with reduced disease-specific survival. The significant predictors of metastasis were four or more high-risk features or tumors with a concurrent invasion deeper than 5 mm and PNI.
Conclusion
For high-risk cSCC, SNB is a safe and feasible staging technique. The total number of high risk features and certain combinations of high-risk features predicted metastasis better than individual high-risk features.
Journal Article
Has land use pushed terrestrial biodiversity beyond the planetary boundary? A global assessment
by
Purvis, Andy
,
Simmons, Benno I.
,
Whitmee, Sarah
in
Assessments
,
Biodiversity
,
Biodiversity hot spots
2016
Land use and related pressures have reduced local terrestrial biodiversity, but it is unclear how the magnitude of change relates to the recently proposed planetary boundary (\"safe limit\"). We estimate that land use and related pressures have already reduced local biodiversity intactness–the average proportion of natural biodiversity remaining in local ecosystems–beyond its recently proposed planetary boundary across 58.1% of the world's land surface, where 71.4% of the human population live. Biodiversity intactness within most biomes (especially grassland biomes), most biodiversity hotspots, and even some wilderness areas is inferred to be beyond the boundary. Such widespread transgression of safe limits suggests that biodiversity loss, if unchecked, will undermine efforts toward long-term sustainable development.
Journal Article
Utility of a buccal swab point-of-care test for the IFNL4 genotype in the era of direct acting antivirals for hepatitis C virus
by
Lin, Shang-Kuan
,
Ala, Aftab
,
McCabe, Leanne
in
Analysis
,
Antiviral agents
,
Antiviral Agents - therapeutic use
2023
The CC genotype of the IFNL4 gene is known to be associated with increased Hepatitis C (HCV) cure rates with interferon-based therapy and may contribute to cure with direct acting antivirals. The Genedrive® IFNL4 is a CE marked Point of Care (PoC) molecular diagnostic test, designed for in vitro diagnostic use to provide rapid, real-time detection of IFNL4 genotype status for SNP rs12979860.
120 Participants were consented to a substudy comparing IFNL4 genotyping results from a buccal swab analysed on the Genedrive® platform with results generated using the Affymetix UK Biobank array considered to be the gold standard.
Buccal swabs were taken from 120 participants for PoC IFNL4 testing and a whole blood sample for genetic sequencing. Whole blood genotyping vs. buccal swab PoC testing identified 40 (33%), 65 (54%), and 15 (13%) had CC, CT and TT IFNL4 genotype respectively. The Buccal swab PoC identified 38 (32%) CC, 64 (53%) CT and 18 (15%) TT IFNL4 genotype respectively. The sensitivity and specificity of the buccal swab test to detect CC vs non-CC was 90% (95% CI 76-97%) and 98% (95% CI 91-100%) respectively.
The buccal swab test was better at correctly identifying non-CC genotypes than CC genotypes. The high specificity of the Genedrive® assay prevents CT/TT genotypes being mistaken for CC, and could avoid patients being identified as potentially 'good responders' to interferon-based therapy.
Journal Article
Public Hospital Pharmacists’ Perceptions and Knowledge of Antibiotic Use and Resistance: A Multicenter Survey
by
Tan, Sherene Su Ann
,
Lim, Phin Phin
,
Ganesan, Sunitha
in
antibiotic use and resistance
,
Antibiotics
,
Antimicrobial agents
2020
Antimicrobial Stewardship Program (ASP) has been implemented in major public hospitals in Malaysia, with pharmacists playing a key role in ensuring the appropriate use of antibiotics. This survey aimed to assess the practices, perceptions, and knowledge of public hospital pharmacists on antibiotic use and resistance. A cross-sectional survey involving pharmacists from six public hospitals in Penang was conducted using a self-administered validated questionnaire. The majority of pharmacists perceived that polypharmacy (92%, n = 270) and overuse of broad-spectrum antibiotics (85%, n = 252) can potentially induce resistance of microorganisms and that ensuring the rational use of antibiotics is a shared responsibility between clinicians and pharmacists (94%, n = 278). A large majority of the pharmacists think that formal training in infectious disease should be a pre-requisite for pharmacists in ASP (93%, n = 273). In terms of antibiotic selection, the availability of antibiotics in hospital (81%, n = 234) and patient’s clinical condition (68%, n = 196) are more of a concern to the pharmacists. A total of 65% of the respondents (n = 192) demonstrated good levels of knowledge with a mean knowledge score of 10.1 out of 13 (95% CI: 9.95; 10.31). Pharmacists from the managerial level, ward pharmacy, in-patient, and medication therapy adherence clinic (MTAC) unit had better knowledge of antibiotics compared to pharmacists from other units (p < 0.001). Antibiotic knowledge gap had been identified among pharmacists in different work settings, and longer years of service does not warrant good antibiotic knowledge.
Journal Article