ORCID Profile
0000-0002-4675-9982
Current Organisation
University of South Australia
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Publisher: The Company of Biologists
Date: 2018
DOI: 10.1242/DEV.162552
Abstract: The adrenal medulla is composed of neuroendocrine chromaffin cells that secrete adrenaline into the systemic circulation to maintain physiological homeostasis and enable the autonomic stress response. How chromaffin cell precursors colonise the adrenal medulla, and how they become connected to central nervous system derived preganglionic sympathetic neurons remains largely unknown. By combining lineage tracing, gene expression studies, genetic ablation and the analysis of mouse mutants, we demonstrate that preganglionic axons direct chromaffin cell precursors into the adrenal primordia. We further show that preganglionic axons and chromaffin cell precursors require class 3 semaphorin (SEMA3) signalling through neuropilins (NRP) to target the adrenal medulla. Thus, SEMA3s serve as guidance cues to control formation of the adrenal neuroendocrine system by establishing appropriate connections between preganglionic neurons and adrenal chromaffin cells that regulate the autonomic stress response.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 07-2017
Abstract: Sleep disordered breathing in children is associated with increased blood flow velocity and sympathetic overactivity. Sympathetic overactivity results in peripheral vasoconstriction and reduced systemic vascular compliance, which increases blood flow velocity during systole. Augmented blood flow velocity is recognized to promote vascular remodeling. Importantly, increased vascular sympathetic nerve fiber density and innervation in early life plays a key role in the development of early‐onset hypertension in animal models. Examination of sympathetic nerve fiber density of the tonsillar arteries in children undergoing adenotonsillectomy for Sleep disordered breathing will address this question in humans. Thirteen children scheduled for adenotonsillectomy to treat sleep disordered breathing underwent pupillometry, polysomnography, flow‐mediated dilation, resting brachial artery blood flow velocity (velocity time integral), and platelet aggregation. The dorsal lingual artery (tonsil) was stained and immunofluorescence techniques used to determine sympathetic nerve fiber density. Sympathetic nerve fiber density was correlated with increased resting velocity time integral ( r =0.63 P .05) and a lower Neuronal Pupillary Index ( r =−0.71, P .01), as well as a slower mean pupillary constriction velocity (mean, r =−0.64 P .05). A faster resting velocity time integral was associated with a slower peak pupillary constriction velocity ( r =−0.77 P .01) and higher platelet aggregation to collagen antigen ( r =0.64 P .05). Slower mean and peak pupillary constriction velocity were associated with higher platelet aggregation scores ( P .05 P .01, respectively). These results indicate that sympathetic activity is associated with change in both the function and structure of systemic vasculature in children with sleep disordered breathing.
Publisher: American Accounting Association
Date: 25-01-2022
Abstract: We investigate effects of audit evidence in the form of Big Data visualizations on jurors' decisions. Using an experiment with mock juror participants (n = 582), the study examines how visualization design features and audit evidence reliability affect jurors' negligence assessments. We find evidence for interactive effects of visualization design and evidence reliability where mock jurors make higher negligence likelihood judgments when audit evidence reliability is higher, and visualizations are more vivid. Mediation results indicate that the combination of more vivid visualizations and more reliable audit evidence produces stronger emotional responses related to the auditor defendant these negative emotional responses increase the likelihood of finding the auditor to be negligent. Overall, we find that data visualization techniques that can improve audit quality may expose auditors to increased litigation risk. Our study informs academics, auditors, and regulators about the potential effects of audit evidence visualization choices on lay evaluators' judgments.
Publisher: Elsevier BV
Date: 11-2015
DOI: 10.1016/J.PBB.2015.09.006
Abstract: Clozapine is an atypical antipsychotic drug used in the treatment of schizophrenia, which has been shown to reverse behavioural and dendritic spine deficits in mice. It has recently been shown that deficiency of 14-3-3ζ has an association with schizophrenia, and that a mouse model lacking this protein displays several schizophrenia-like behavioural deficits. To test the effect of clozapine in this mouse model, 14-3-3ζ KO mice were administered clozapine (5mg/kg) for two weeks prior to being analysed in a test battery of cognition, anxiety, and despair (depression-like) behaviours. Following behavioural testing brain s les were collected for analysis of specific anatomical defects and dendritic spine formation. We found that clozapine reduced despair behaviour of 14-3-3ζ KO mice in the forced swim test (FST) and altered the behaviour of wild types and 14-3-3ζ KO mice in the Y-maze task. In contrast, clozapine had no effects on hippoc al laminar defects or decreased dendritic spine density observed in 14-3-3ζ KO mice. Our results suggest that clozapine may have beneficial effects on clinical behaviours associated with deficiencies in the 14-3-3ζ molecular pathway, despite having no effects on morphological defects. These findings may provide mechanistic insight to the action of this drug.
Publisher: Springer Science and Business Media LLC
Date: 24-07-2015
DOI: 10.1038/SREP12434
Abstract: Sequencing and expression analyses implicate 14-3-3ζ as a genetic risk factor for neurodevelopmental disorders such as schizophrenia and autism. In support of this notion, we recently found that 14-3-3ζ −/− mice in the Sv/129 background display schizophrenia-like defects. As epistatic interactions play a significant role in disease pathogenesis we generated a new congenic strain in the BALB/c background to determine the impact of genetic interactions on the 14-3-3ζ −/− phenotype. In addition to replicating defects such as aberrant mossy fibre connectivity and impaired spatial memory, our analysis of 14-3-3ζ −/− BALB/c mice identified enlarged lateral ventricles, reduced synaptic density and ectopically positioned pyramidal neurons in all subfields of the hippoc us. In contrast to our previous analyses, 14-3-3ζ −/− BALB/c mice lacked locomotor hyperactivity that was underscored by normal levels of the dopamine transporter (DAT) and dopamine signalling. Taken together, our results demonstrate that dysfunction of 14-3-3ζ gives rise to many of the pathological hallmarks associated with the human condition. 14-3-3ζ-deficient BALB/c mice therefore provide a novel model to address the underlying biology of structural defects affecting the hippoc us and ventricle and cognitive defects such as hippoc al-dependent learning and memory.
No related grants have been discovered for Xiangjun Xu.