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Search Results: 1 - 10 of 3549 matches for " Danny Hon-Fai So "
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Uncoupling Protein-4 (UCP4) Increases ATP Supply by Interacting with Mitochondrial Complex II in Neuroblastoma Cells
Philip Wing-Lok Ho, Jessica Wing-Man Ho, Ho-Man Tse, Danny Hon-Fai So, David Chi-Wai Yiu, Hui-Fang Liu, Koon-Ho Chan, Michelle Hiu-Wai Kung, David Boyer Ramsden, Shu-Leong Ho
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0032810
Abstract: Mitochondrial uncoupling protein-4 (UCP4) protects against Complex I deficiency as induced by 1-methyl-4-phenylpyridinium (MPP+), but how UCP4 affects mitochondrial function is unclear. Here we investigated how UCP4 affects mitochondrial bioenergetics in SH-SY5Y cells. Cells stably overexpressing UCP4 exhibited higher oxygen consumption (10.1%, p<0.01), with 20% greater proton leak than vector controls (p<0.01). Increased ATP supply was observed in UCP4-overexpressing cells compared to controls (p<0.05). Although state 4 and state 3 respiration rates of UCP4-overexpressing and control cells were similar, Complex II activity in UCP4-overexpressing cells was 30% higher (p<0.05), associated with protein binding between UCP4 and Complex II, but not that of either Complex I or IV. Mitochondrial ADP consumption by succinate-induced respiration was 26% higher in UCP4-overexpressing cells, with 20% higher ADP:O ratio (p<0.05). ADP/ATP exchange rate was not altered by UCP4 overexpression, as shown by unchanged mitochondrial ADP uptake activity. UCP4 overexpression retained normal mitochondrial morphology in situ, with similar mitochondrial membrane potential compared to controls. Our findings elucidate how UCP4 overexpression increases ATP synthesis by specifically interacting with Complex II. This highlights a unique role of UCP4 as a potential regulatory target to modulate mitochondrial Complex II and ATP output in preserving existing neurons against energy crisis.
Information Encryption Based on Using Arbitrary Two-Step Phase-Shift Interferometry  [PDF]
Chi-Ching Chang, Wen-Ho Wu, Min-Tzung Shiu, Wang-Ta Hsieh, Je-Chung Wang, Hon-Fai Yau
Optics and Photonics Journal (OPJ) , 2011, DOI: 10.4236/opj.2011.14032
Abstract: A deterministic phase-encoded encryption system is proposed. A lenticular lens array (LLA) sheet with a particular LPI (lenticular per inch) number is chosen as a modulator (key) instead of the random phase molator. The suggested encryption scheme is based on arbitrary two-step phase-shift interferometry (PSI), using an unknown phase step. The encryption and decryption principle is based on an LLA in arbitrary unknown two-step PSI. Right key holograms can be used to theoretically show that the object wavefront is the only one left in the hologram plane and that all accompanying undesired terms are eliminated. The encrypted image can therefore be numerically and successfully decrypted with the right key in the image plane. The number of degrees of freedom of the encryption scheme increases with the distance from the object and the LLA to the CCD, and also with the unknown phase-step and the LLA LPI number. Computer simulations are performed to verify the encryption and decryption principles without a key, with the wrong key and with the right key. Optical experiments are also performed to validate them.
Skeletal Muscle Fascicle Arrangements Can Be Reconstructed Using a Laplacian Vector Field Simulation
Hon Fai Choi, Silvia S. Blemker
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0077576
Abstract: Skeletal muscles are characterized by a large diversity in anatomical architecture and function. Muscle force and contraction are generated by contractile fiber cells grouped in fascicle bundles, which transmit the mechanical action between origin and insertion attachments of the muscle. Therefore, an adequate representation of fascicle arrangements in computational models of skeletal muscles is important, especially when investigating three-dimensional muscle deformations in finite element models. However, obtaining high resolution in vivo measurements of fascicle arrangements in skeletal muscles is currently still challenging. This motivated the development of methods in previous studies to generate numerical representations of fascicle trajectories using interpolation templates. Here, we present an alternative approach based on the hypothesis of a rotation and divergence free (Laplacian) vector field behavior which reflects observed physical characteristics of fascicle trajectories. To obtain this representation, the Laplace equation was solved in anatomical reconstructions of skeletal muscle shapes based on medical images using a uniform flux boundary condition on the attachment areas. Fascicle tracts were generated through a robust flux based tracing algorithm. The concept of this approach was demonstrated in two-dimensional synthetic examples of typical skeletal muscle architectures. A detailed evaluation was performed in an example of the anatomical human tibialis anterior muscle which showed an overall agreement with measurements from the literature. The utility and capability of the proposed method was further demonstrated in other anatomical examples of human skeletal muscles with a wide range of muscle shapes and attachment morphologies.
The Effects of Ganoderma lucidum on Initial Events Related to the Bacillus Calmette-Guérin Efficacy and Toxicity on High-Risk Uroepithelial Cells: An in Vitro Preliminary Study  [PDF]
John Wai-Man Yuen, Mayur-Danny I. Gohel, Chi-Fai Ng
Chinese Medicine (CM) , 2013, DOI: 10.4236/cm.2013.42009
Abstract:

A novel prophylactic regimen is demanded for preventing bladder cancer recurrence, because of the high side-effect tolls of conventional adjuvant Bacillus Calmette-Guérin (BCG) immunotherapy, in addition to its only moderate efficacy. In vitro and animal studies have demonstrated the anti-cancer properties of a medicinal mushroom called Ganoderma lucidum (GL). In this study, a pre-malignant human uroepithelial cells (HUC-PC) model was utilized to compare the effectiveness between ethanol extract of GL (GLe) and BCG on interleukin-6 (IL-6) secretion and lactate dehydrogenase (LDH) cytotoxicity. Additionally, parameters relevant to the BCG efficacy and safety, including free soluble fibronectin (FN) and cell-surface glycosaminoglycans (GAGs) levels were tested, following the exposure of GLe to the cells. GLe at 100 μg/ml and BCG at 4.8 × 107 CFU were shown to induce equivalent levels of IL-6, suggesting the potential synergism, while the tested concentrations of GLe were non-cytotoxic. During the initial four hours of GLe exposure, the free FN concentrations in harvested media were significantly reduced that might facilitate the binding of BCG for uroepithelial internalization to enhance BCG efficacy. Furthermore, the cell membrane-bound GAGs levels of HUC-PC cells were significant increased in response to GLe to suggest cellular protection from BCG infection. In summary, current findings suggest the potential additive synergism of GLe with the BCG efficacy, as well as its protective effects, and thus reducing the BCG toxicity.

A Unifying Framework for Evaluating the Predictive Power of Genetic Variants Based on the Level of Heritability Explained
Hon-Cheong So,Pak C. Sham
PLOS Genetics , 2010, DOI: 10.1371/journal.pgen.1001230
Abstract: An increasing number of genetic variants have been identified for many complex diseases. However, it is controversial whether risk prediction based on genomic profiles will be useful clinically. Appropriate statistical measures to evaluate the performance of genetic risk prediction models are required. Previous studies have mainly focused on the use of the area under the receiver operating characteristic (ROC) curve, or AUC, to judge the predictive value of genetic tests. However, AUC has its limitations and should be complemented by other measures. In this study, we develop a novel unifying statistical framework that connects a large variety of predictive indices together. We showed that, given the overall disease probability and the level of variance in total liability (or heritability) explained by the genetic variants, we can estimate analytically a large variety of prediction metrics, for example the AUC, the mean risk difference between cases and non-cases, the net reclassification improvement (ability to reclassify people into high- and low-risk categories), the proportion of cases explained by a specific percentile of population at the highest risk, the variance of predicted risks, and the risk at any percentile. We also demonstrate how to construct graphs to visualize the performance of risk models, such as the ROC curve, the density of risks, and the predictiveness curve (disease risk plotted against risk percentile). The results from simulations match very well with our theoretical estimates. Finally we apply the methodology to nine complex diseases, evaluating the predictive power of genetic tests based on known susceptibility variants for each trait.
Teaching and learning activities of flight and paper planes
Pun Hon NG,Yeuk Mon SO
Asia-Pacific Forum on Science Learning and Teaching , 2004,
Abstract: Human beings are always interested in and curious about flying. Basically, the physics of flight are the three Newton’s Laws of Motion. The forces acting on a flying object include the gravity, the lift, the drag, the thrust and the upthrust etc. Every flying phenomenon is due to the resultant of these forces. Hence, flight is not just an interesting topic for students. It also provides a context in which students can apply corresponding physics knowledge. This paper first briefly summarizes the history and the physics of flight. Some common errors on the explanation of the production of lift are discussed. In order to avoid complicated fluid dynamics calculation, we use a phenomenological approach to explain how the lift is produced. Then, some teaching and learning activities of flight and paper planes are introduced.
Drug discovery from Chinese medicine against neurodegeneration in Alzheimer's and vascular dementia
Yuen-Shan Ho, Kwok-Fai So, Raymond Chang
Chinese Medicine , 2011, DOI: 10.1186/1749-8546-6-15
Abstract: Alzheimer's disease (AD) and vascular dementia (VaD) are the major forms of dementia. In addition, in the postmortem brains of the late stage of Parkinson's disease/Lewy body disease also find pathological hallmarks of AD [1]. Senile dementia is the progressive decline of memory and some related cognitive functions in the elderly. The global dementia population is predicted to reach 81.1 million by 2040 [2]. In 2010, the estimated prevalence of senile dementia in China is 6.0 to 7.0 million, accounting for about one-sixth of the global prevalence; the prevalence is expected to increase to 22.5 million by 2040, accounting for one-fourth of the global prevalence by that time [3]. The rapid increase in the number of dementia patients urgently demands effective prevention and treatment. Current approaches to dementia-related neurodegenerative diseases still highly rely on relieving symptoms. As some Chinese medicinal herbs have been used in treating dementia, many researchers are now turning to Chinese medicine for identifying potential neuroprotective agents or disease-modifying agent. This article reviews the strategy in the research of Chinese medicine in dementia related-neurodegenerative diseases.AD is clinically characterized by the progressive loss of memory, cognitive functions and behavioral changes. The pathogenesis of AD has been widely studied [4,5], in which beta-amyloid (Aβ) peptide and hyperphosphorylated tau protein as components of extracellular senile plaques and intracellular neurofibrillary tangles, respectively, are believed to be the targets for developing disease-modifying drugs. Current AD treatments are all symptom-relieving agents and heavily rely on the use of acetylcholinesterase (AChE) inhibitors (donepezil, rivastigmine and galantamine). AChE inhibitors slow down the degradation of the neurotransmitter acetylcholine, thereby increasing its bioavailability. Another approved AD treatment aims to reduce glutamate excitotoxicity. Memantine, the
Dendritic Morphology of Caudal Periaqueductal Gray Projecting Retinal Ganglion Cells in Mongolian Gerbil (Meriones unguiculatus)
Chaoran Ren, Mingliang Pu, Qi Cui, Kwok-Fai So
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0103306
Abstract: In this study we investigated the morphological features of the caudal periaqueductal gray (cPAG)-projecting retinal ganglion cells (RGCs) in Mongolian gerbils using retrograde labeling, in vitro intracellular injection, confocal microscopy and three-dimensional reconstruction approaches. cPAG-projecting RGCs exhibit small somata (10–17 μm) and irregular dendritic fields (201–298 μm). Sizes of somata and dendritic fields do not show obvious variation at different distance from the optic disk (eccentricity). Dendrites are moderately branched. Morphological analysis (n = 23) reveals that cPAG-projecting RGCs ramified in sublamina a and b in the inner plexiform layer. These cells exhibit different stratification patterns based on the thickness of dendritic bands in sublaminas a and b: majority of analyzed cells (16 out of 23) have two bands of arborizations share similar thickness. The rest of analyzed cells (7 out of 23) exhibit thinner band in sublamina a than in sublamina b. Together, the present study suggests that cPAG of Mongolian gerbil could receive direct retinal inputs from two types of bistratified RGCs. Furthermore, a small subset of melanopsin-expressing RGCs (total 41 in 6 animals) is shown to innervate the rostral PAG (rPAG). Functional characteristics of these non-visual center projecting RGCs remain to be determined.
Genome-Wide Copy Number Analysis Uncovers a New HSCR Gene: NRG3
Clara Sze-Man Tang equal contributor,Guo Cheng equal contributor,Man-Ting So equal contributor,Benjamin Hon-Kei Yip,Xiao-Ping Miao,Emily Hoi-Man Wong,Elly Sau-Wai Ngan,Vincent Chi-Hang Lui,You-Qiang Song,Danny Chan,Kenneth Cheung,Zhen-Wei Yuan,Liu Lei,Patrick Ho-Yu Chung,Xue-Lai Liu,Kenneth Kak-Yuen Wong,Christian R. Marshall,Steve Scherer,Stacey S. Cherny,Pak-Chung Sham,Paul Kwong-Hang Tam,Maria-Mercè Garcia-Barceló
PLOS Genetics , 2012, DOI: 10.1371/journal.pgen.1002687
Abstract: Hirschsprung disease (HSCR) is a congenital disorder characterized by aganglionosis of the distal intestine. To assess the contribution of copy number variants (CNVs) to HSCR, we analysed the data generated from our previous genome-wide association study on HSCR patients, whereby we identified NRG1 as a new HSCR susceptibility locus. Analysis of 129 Chinese patients and 331 ethnically matched controls showed that HSCR patients have a greater burden of rare CNVs (p = 1.50×10？5), particularly for those encompassing genes (p = 5.00×10？6). Our study identified 246 rare-genic CNVs exclusive to patients. Among those, we detected a NRG3 deletion (p = 1.64×10？3). Subsequent follow-up (96 additional patients and 220 controls) on NRG3 revealed 9 deletions (combined p = 3.36×10？5) and 2 de novo duplications among patients and two deletions among controls. Importantly, NRG3 is a paralog of NRG1. Stratification of patients by presence/absence of HSCR–associated syndromes showed that while syndromic–HSCR patients carried significantly longer CNVs than the non-syndromic or controls (p = 1.50×10？5), non-syndromic patients were enriched in CNV number when compared to controls (p = 4.00×10？6) or the syndromic counterpart. Our results suggest a role for NRG3 in HSCR etiology and provide insights into the relative contribution of structural variants in both syndromic and non-syndromic HSCR. This would be the first genome-wide catalog of copy number variants identified in HSCR.
Synergistic Cytotoxic Effects of Ganoderma lucidum and Bacillus Calmette Guérin on Premalignant Urothelial HUC-PC Cells and Its Regulation on Proinflammatory Cytokine Secretion
John Wai-man Yuen,Mayur-Danny I. Gohel,Chi-fai Ng
Evidence-Based Complementary and Alternative Medicine , 2012, DOI: 10.1155/2012/147896
Abstract: Bacillus Calmette-Guérin (BCG) is conventionally used as an adjuvant immunotherapy to reduce the recurrence of bladder cancer. To address the issues of efficacy and safety, an ethanol extract of Ganoderma lucidum (GLe) was evaluated for its interaction with BCG. In a model of premalignant human uroepithelial cells (HUC-PC), GLe exerted immediate cytotoxic effects while BCG showed a delayed response, given that both were immunological active in inducing the secretion of interleukin (IL)-6, IL-8, and monocyte chemotactic protein-1 (MCP-1). Synergistic cytotoxic effects were observed when cells were either coincubated with both drugs or firstly preincubated with GLe. Synergism between GLe and BCG was demonstrated to achieve a complete cytostasis in 24 hours, and such effects were progressed in the subsequent 5 days. However, the pretreatment of GLe resulted in suppression of IL-6, IL-8, and MCP-1 secretions without affecting the cytotoxicity. Given that numerous proinflammatory cytokines are associated with the high side effects toll of BCG, results herein suggested the potential implications of GL to supplement the BCG immunotherapy in bladder cancer, for better efficacy and reducing side effects.
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