Sustained Delivery of Bioactive GDNF from Collagen and Alginate-Based Cell-Encapsulating Gel Promoted Photoreceptor Survival in an Inherited Retinal Degeneration Model

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Factors contributing to officers’ fatigue in high-speed maritime craft operations

Author name used in this publication: Jimmy J. M. Ng2005-2006 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Diffusivity of the uncinate fasciculus in heroin users relates to their levels of anxiety

Heroin use is closely associated with emotional dysregulation, which may explain its high comorbidity with disorders such as anxiety and depression. However, the understanding of the neurobiological etiology of the association between heroin use and emotional dysregulation is limited. Previous studies have suggested an impact of heroin on diffusivity in white matter involving the emotional regulatory system, but the specificity of this finding remains to be determined. Therefore, this study investigated the association between heroin use and diffusivity of white matter tracts in heroin users and examined whether the tracts were associated with their elevated anxiety and depression levels. A sample of 26 right-handed male abstinent heroin users (25 to 42 years of age) and 32 matched healthy controls (19 to 55 years of age) was recruited for this study. Diffusion tensor imaging data were collected, and their levels of anxiety and depression were assessed using the Hospital Anxiety and Depression Scale. Our findings indicated that heroin users exhibited higher levels of anxiety and depression, but the heroin use-associated left uncinate fasciculus was only related to their anxiety level, suggesting that association between heroin and anxiety has an incremental organic basis but that for depression could be a threshold issue. This finding improves our understanding of heroin addiction and its comorbid affective disorder and facilitates future therapeutic development.published_or_final_versio

Meditation-induced neuroplastic changes in amygdala activity during negative affective processing

Recent evidence suggests that the effects of meditation practice on affective processing and resilience have the potential to induce neuroplastic changes within the amygdala. Notably, literature speculates that meditation training may reduce amygdala activity during negative affective processing. Nonetheless, studies have thus far not verified this speculation. In this longitudinal study, participants (N = 21, 9 men) were trained in awareness-based compassion meditation (ABCM) or matched relaxation training. The effects of meditation training on amygdala activity were examined during passive viewing of affective and neutral stimuli in a non-meditative state. We found that the ABCM group exhibited significantly reduced anxiety and right amygdala activity during negative emotion processing than the relaxation group. Furthermore, ABCM participants who performed more compassion practice had stronger right amygdala activity reduction during negative emotion processing. The lower right amygdala activity after ABCM training may be associated with a general reduction in reactivity and distress. As all participants performed the emotion processing task in a non-meditative state, it appears likely that the changes in right amygdala activity are carried over from the meditation practice into the non-meditative state. These findings suggest that the distress-reducing effects of meditation practice on affective processing may transfer to ordinary states, which have important implications on stress management.Department of Rehabilitation Sciences2016-2017 > Academic research: refereed > Publication in refereed journalbcr

Upregulation of Barrel GABAergic Neurons Is Associated with Cross-Modal Plasticity in Olfactory Deficit

Background: Loss of a sensory function is often followed by the hypersensitivity of other modalities in mammals, which secures them well-awareness to environmental changes. Cellular and molecular mechanisms underlying cross-modal sensory plasticity remain to be documented. Methodology/Principal Findings: Multidisciplinary approaches, such as electrophysiology, behavioral task and immunohistochemistry, were used to examine the involvement of specific types of neurons in cross-modal plasticity. We have established a mouse model that olfactory deficit leads to a whisking upregulation, and studied how GABAergic neurons are involved in this cross-modal plasticity. In the meantime of inducing whisker tactile hypersensitivity, the olfactory injury recruits more GABAergic neurons and their fine processes in the barrel cortex, as well as upregulates their capacity of encoding action potentials. The hyperpolarization driven by inhibitory inputs strengthens the encoding ability of their target cells. Conclusion/Significance: The upregulation of GABAergic neurons and the functional enhancement of neuronal networks may play an important role in cross-modal sensory plasticity. This finding provides the clues for developing therapeuti

Cell-encapsulated device for intraocular delivery of glial-cell derived neurotrophic factor (GDNF)

Theme: Life-changing ResearchPoster Session 142 - Drug Delivery I: Program ID: 1073 - C0050PURPOSE: While GDNF is able to exert neuroprotective effects on photoreceptor cells, successful administration of such therapeutic protein has been hindered by short half-life and the lack of a sustained drug delivery method. A cell-based immunoisolated intraocular drug delivery device for continuous GDNF release was designed. The photoreceptor rescuing effects in a rat model with inherited retinal degeneration were examined after the implantation of the gel device. METHODS: HEK293 cells that overexpress GDNF were encapsulated in a composite matrix constituted of 2mg/ml collagen and 1% alginate. The collagen-alginate gel device was intravitreally injected into Royal College of Surgeons rats on post-natal day 28 (P28). Rats were randomly divided into four groups: sham, un-operated, vehicle control, and treatment groups. Vitreous contents were collected for GDNF content assessment on P35 and P42. Enucleation was carried out on P56 for histological evaluations. H&E stained paraffin sections of the retina were examined for the degree of morphological rescue via quantifying the outer nuclear layer photoreceptors at various retinal regions. RESULTS: Significant amount of GDNF was released into the vitreous after 7 and 14 days of device implantation. Outer nuclear layer (ONL) linings in the treatment group were better aligned at the central retinal regions when compared to the control groups. Increase in mean ONL cell counts were observed across the whole retina, in particularly, the center of the inferior retina. CONCLUSIONS: Cell growth, proliferation and sustained release of GDNF were achieved through implanting the cell-encapsulating collagen-alginate gel device, resulting in morphological rescue of photoreceptor cells in vivo. This system could potentially be applied as a sustained drug release platform of GDNF and/or other therapeutic proteins in various ocular conditions involving similar pathological phenotypes.link_to_OA_fulltex

Modified automatic teller machine prototype for older adults: A case study of participative approach to inclusive design

The goal of this study was to enhance an existing automated teller machine (ATM) human-machine interface in order to accommodate the needs of older adults. Older adults were involved in the design and field test of the modified ATM prototype. The design of the user interface and functionality took the cognitive and physical abilities of older adults into account. The modified ATM system included only "cash withdrawal" and "transfer" functions based on the task demands and needs for services of older adults. One hundred and forty-one older adults (aged 60 or above) participated in the field test by operating modified or existing ATM systems. Those who operated the modified system were found to have significantly higher success rates than those who operated the existing system. The enhancement was most significant among older adults who had lower ATM-related abilities, a lower level of education, and no prior experience of using ATMs. This study demonstrates the usefulness of using a universal design and participatory approach to modify the existing ATM system for use by older adults. However, it also leads to a reduction in functionality of the enhanced system. Future studies should explore ways to develop a universal design ATM system which can satisfy the abilities and needs of all users in the entire population. © 2008 Elsevier Ltd. All rights reserved.link_to_subscribed_fulltex

Emotion recognition in Chinese people with schizophrenia

This study examined whether people with paranoid or nonparanoid schizophrenia would show emotion-recognition deficits, both facial and prosodic. Furthermore, this study examined the neuropsychological predictors of emotion-recognition ability in people with schizophrenia. Participants comprised 86 people, of whom: 43 were people diagnosed with schizophrenia and 43 were controls. The 43 clinical participants were placed in either the paranoid group (n = 19) or the nonparanoid group (n = 24). Each participant was administered the Facial Emotion Recognition task and the Prosodic Recognition task, together with other neuropsychological measures of attention and visual perception. People suffering from nonparanoid schizophrenia were found to have deficits in both facial and prosodic emotion recognition, after correction for the differences in the intelligence and depression scores between the two groups. Furthermore, spatial perception was observed to be the best predictor of facial emotion identification in individuals with nonparanoid schizophrenia, whereas attentional processing control predicted both prosodic emotion identification and discrimination in nonparanoid schizophrenia patients. Our findings suggest that patients with schizophrenia in remission may still suffer from impairment of certain aspects of emotion recognition. © 2007 Elsevier Ireland Ltd. All rights reserved.link_to_subscribed_fulltex