University of Hong Kong

23 articles published in JoVE

• Neuroscience

  
  Modulation of the Neurophysiological Response to Fearful and Stressful Stimuli Through Repetitive Religious Chanting Hin Hung Sik¹, Georgios T. Halkias¹, Chunqi Chang², Junling Gao¹, Hang Kin Leung¹, Bonnie Wai Yan Wu^{1 1}Buddhism and Science Research Lab, Centre of Buddhist Studies, The University of Hong Kong, ²School of Biomedical Engineering, Shenzhen University The present event-related potential (ERP) study provides a unique protocol for investigating how religious chanting can modulate negative emotions. The results demonstrate that the late positive potential (LPP) is a robust neurophysiological response to negative emotional stimuli and can be effectively modulated by repetitive religious chanting.

• Biology

  
  Visualization and Quantification of Brown and Beige Adipose Tissues in Mice using [¹⁸F]FDG Micro-PET/MR Imaging Qing Liu*^1,2, Kel Vin Tan*³, Hing-Chiu Chang³, Pek-Lan Khong³, Xiaoyan Hui^{1,2,4 1}State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, ²Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, ³Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, ⁴School of Biomedical Sciences, Institute of Vascular Medicine, Chinese University of Hong Kong Functional imaging and quantitation of thermogenic adipose depots in mice using a micro-PET/MR imaging-based approach.

• Medicine

  
  Intratracheal Administration of Dry Powder Formulation in Mice Yingshan Qiu¹, Qiuying Liao¹, Michael Y.T. Chow^1,2, Jenny K.W. Lam^{1 1}Department of Pharmacology and Pharmacy, LKS Faculty of Medicine, The University of Hong Kong, ²Advanced Drug Delivery Group, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney Dry powder formulations for inhalation have great potential in treating respiratory diseases. Before entering human studies, it is necessary to evaluate the efficacy of the dry powder formulation in preclinical studies. A simple and noninvasive method of the administration of dry powder in mice through the intratracheal route is presented.

• Medicine

  
  Establishing a Swine Model of Post-myocardial Infarction Heart Failure for Stem Cell Treatment Sijia Sun*¹, Yu Jiang*¹, Zhe Zhen^1,2, Wing-Hon Lai^1,2, Songyan Liao^1,2, Hung-Fat Tse^{1,2 1}Cardiology Division, Department of Medicine, Queen Mary Hospital, University of Hong Kong, ²Shenzhen Institutes of Research and Innovation, University of Hong Kong We sought to establish a swine model of heart failure induced by left circumflex artery blockage and rapid pacing to test the effect and safety of intramyocardial administration of stem cells for cell-based therapies.

• Chemistry

  
  Asymmetric Thermoelectrochemical Cell for Harvesting Low-grade Heat under Isothermal Operation Kaiyu Mu*¹, Xun Wang*¹, Ka Ho Li¹, Yu-Ting Huang¹, Shien-Ping Feng^{1 1}Electrochemical Nanoengineering Group, Department of Mechanical Engineering, University of Hong Kong Low-grade heat is abundant, but its efficient recovery is still a great challenge. We report an asymmetric thermoelectrochemical cell using graphene oxide as a cathode and polyaniline as an anode with KCl as the electrolyte. This cell works under isothermal heating, exhibiting a high heat-to-electricity conversion efficiency in low-temperature regions.

• Biology

  
  Assessment of Vascular Tone Responsiveness using Isolated Mesenteric Arteries with a Focus on Modulation by Perivascular Adipose Tissues Daniels Konja¹, Cuiting Luo¹, Wai Yan Sun¹, Kangmin Yang¹, Andy W.C. Man¹, Aimin Xu¹, Paul M. Vanhoutte¹, Yu Wang^{1 1}The State Key Laboratory of Pharmaceutical Biotechnology and the Department of Pharmacology and Pharmacy, University of Hong Kong The protocol describes the use of wire myography to evaluate the transmural isometric tension of mesenteric arteries isolated from mice, with special consideration of the modulation by factors released from endothelial cells and perivascular adipose tissues.

• Behavior

  
  A Behavioral Test Battery for the Repeated Assessment of Motor Skills, Mood, and Cognition in Mice Ran You^1,2,3, Yan Liu³, Raymond Chuen-Chung Chang^{3 1} A comprehensive behavioral test battery of motor skills, mood—including social interaction, depression, and anxiety—and cognition is designed for the repeated assessment of neurodegeneration-related behavioral changes in mice.

• Neuroscience

  
  Screening of Axonal Degeneration in Carpal Tunnel Syndrome Using Ultrasonography and Nerve Conduction Studies Xue Deng¹, Lai-Heung Phoebe Chau², Suk-Yee Chiu², Kwok-Pui Leung³, Yong Hu¹, Wing-Yuk Ip^{1 1}Department of Orthopedics & Traumatology, The University of Hong Kong, ²Clinical Electro-diagnostic Unit, Tung Wah Hospital, ³Department of Medicine, The University of Hong Kong Here we present a protocol using nerve conduction studies and ultrasound to screen potential axonal degeneration associated with carpal tunnel syndrome. The criteria for differentiation are established. Compared to conventional approaches, this method is noninvasive, convenient, and efficient, with an overall satisfactory accuracy, sensitivity, and specificity.

• Developmental Biology

  
  A Familial Hypercholesterolemia Human Liver Chimeric Mouse Model Using Induced Pluripotent Stem Cell-derived Hepatocytes Jiayin Yang*^1,2,6, Lai-Yung Wong*², Xiao-Yu Tian*³, Rui Wei^1,2, Wing-Hon Lai², Ka-Wing Au², Zhiwei Luo^4,5, Carl Ward^4,5, Wai-In Ho², David P. Ibañez^4,5, Hao Liu^4,5, Xichen Bao^4,5, Baoming Qin^4,5, Yu Huang³, Miguel A. Esteban^4,5,7, Hung-Fat Tse^{1,2,6,7 1}Department of Medicine, University of Hong Kong-Shenzhen Hospital, ²The Cardiology Division, Department of Medicine, Li Ka Shing Faculty of Medicine, University of Hong Kong, ³School of Biomedical Sciences, Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, ⁴Key Laboratory of Regenerative Biology of the Chinese Academy of Sciences, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health and Guangzhou Medical University, ⁵Laboratory of RNA, Chromatin, and Human Disease, CAS Key Laboratory of Regenerative Biology and Guangdong Provincial Key Laboratory of Stem Cells and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, ⁶Research Centre of Heart, Brain, Hormone, and Healthy Ageing, Li Ka Shing Faculty of Medicine, University of Hong Kong, ⁷Hong Kong-Guangdong Stem Cell and Regenerative Medicine Research Centre, University of Hong Kong and Guangzhou Institutes of Biomedicine and Health Here, we present a protocol to generate a human liver chimeric mouse model of familial hypercholesterolemia using human induced pluripotent stem cell-derived hepatocytes. This is a valuable model for testing new therapies for hypercholesterolemia.

• Engineering

  
  Microfluidic Imaging Flow Cytometry by Asymmetric-detection Time-stretch Optical Microscopy (ATOM) Anson H. L. Tang¹, Queenie T. K. Lai¹, Bob M. F. Chung², Kelvin C. M. Lee¹, Aaron T. Y. Mok¹, G. K. Yip¹, Anderson H. C. Shum², Kenneth K. Y. Wong¹, Kevin K. Tsia^{1 1}Department of Electrical and Electronic Engineering, The University of Hong Kong, ²Department of Mechanical Engineering, The University of Hong Kong This protocol describes the implementation of an asymmetric-detection time-stretch optical microscopy system for single-cell imaging in ultrafast microfluidic flow and its applications in imaging flow cytometry.

• Engineering

  
  Scalable Solution-processed Fabrication Strategy for High-performance, Flexible, Transparent Electrodes with Embedded Metal Mesh Arshad Khan¹, Sangeon Lee², Taehee Jang³, Ze Xiong⁴, Cuiping Zhang^1,5, Jinyao Tang⁴, L. Jay Guo^2,3, Wen-Di Li^{1,5 1}Department of Mechanical Engineering, University of Hong Kong, ²Department of Mechanical Engineering, University of Michigan, ³Department of Electrical Engineering and Computer Science, University of Michigan, ⁴Department of Chemistry, University of Hong Kong, ⁵HKU-Shenzhen Institute of Research and Innovation This protocol describes a solution-based fabrication strategy for high-performance, flexible, transparent electrodes with fully-embedded, thick metal mesh. Flexible transparent electrodes fabricated by this process demonstrate among the highest reported performances, including ultra-low sheet resistance, high optical transmittance, mechanical stability under bending, strong substrate adhesion, surface smoothness, and environmental stability.

• Developmental Biology

  
  Hypoxic Preconditioning of Marrow-derived Progenitor Cells As a Source for the Generation of Mature Schwann Cells Yat-Ping Tsui*¹, Alan Kwan-Long Mung*¹, Ying-Shing Chan¹, Daisy Kwok-Yan Shum¹, Graham Ka-Hon Shea^{2 1}School of Biomedical Sciences, The University of Hong Kong, ²Department of Orthopaedics and Traumatology, The University of Hong Kong Marrow stromal cells (MSCs) with neural potential exist within the bone marrow. Our protocol enriches this population of cells via hypoxic preconditioning and thereafter directs them to become mature Schwann cells.

• Behavior

  
  Using Wavelet Entropy to Demonstrate how Mindfulness Practice Increases Coordination between Irregular Cerebral and Cardiac Activities Hin Hung Sik¹, Junling Gao^1,2, Jicong Fan¹, Bonnie Wai Yan Wu¹, Hang Kin Leung¹, Yeung Sam Hung^{2 1}Centre of Buddhist Studies, The University of Hong Kong, ²Department of Electrical and Electronic Engineering, The University of Hong Kong This manuscript describes how to use the wavelet entropy index to analyze high-density electroencephalography (EEG) and electrocardiography (ECG) data. We show that the irregularity of cerebral and cardiac activities became more coordinated during mindfulness-based stress reduction practice.

• Medicine

  
  Minimally Invasive Transverse Aortic Constriction in Mice Aung Moe Zaw¹, Connor M. Williams², Helen K. W. Law³, Billy Kwok Chong Chow^{1 1}School of Biological Sciences, The University of Hong Kong, ²College of Arts and Science, New York University, ³Department of Health Technology and Informatics, Faculty of Health and Social Sciences, The Hong Kong Polytechnic University Minimally invasive transverse aortic constriction (MTAC) conserves the essentials of regular transverse aortic constriction (TAC) while eliminating the use of a ventilator with tracheal intubation. It proves to be a highly desirable method for high-throughput studies on left ventricular overload, particularly in translational studies.

• Biology

  
  Characterization of Calcification Events Using Live Optical and Electron Microscopy Techniques in a Marine Tubeworm Vera B. S. Chan¹, Takashi Toyofuku², George Wetzel³, Laxmikant Saraf³, Vengatesen Thiyagarajan⁴, Andrew S. Mount^{1 1}Department of Biological Sciences, Clemson University, ²Department of Marine Biodiversity Research (BioDive), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), ³Advanced Material Research Laboratory (AMRL), Clemson University, ⁴Swire Institute of Marine Sciences and School of Biological Sciences, The University of Hong Kong We demonstrate the use of various microscopy methods that are useful in observing the calcification of a tubeworm, Hydroides elegans, as well as locating and characterizing the first calcified material. Live microscopy and electron microscopy are used together to provide functional and material information that are important in studying biomineralization.

• Bioengineering

  
  Modeling Ovarian Cancer Multicellular Spheroid Behavior in a Dynamic 3D Peritoneal Microdevice Shan-Shan Li*¹, Carman K. M. Ip*¹, Matthew Y. H. Tang*², Samuel K. H. Sy², Susan Yung³, Tak-Mao Chan³, Mengsu Yang⁴, Ho Cheung Shum², Alice S.T. Wong^{1 1}School of Biological Sciences, University of Hong Kong, ²Department of Mechanical Engineering, University of Hong Kong, ³Department of Medicine, University of Hong Kong, ⁴Department of Biomedical Sciences, Key Laboratory of Biochip Technology, Biotech and Health Centre, Shenzhen Research Institutes of City University of Hong Kong To study ovarian tumor progression in a physiologically relevant model, multicellular spheroids were cultured in a microdevice under simulated fluid flow. This dynamic 3D model emulates the intraperitoneal environment with the cellular and mechanical components where ovarian cancer metastasis occurs.

• Bioengineering

  
  Construction of Defined Human Engineered Cardiac Tissues to Study Mechanisms of Cardiac Cell Therapy Timothy J. Cashman¹, Rebecca Josowitz², Bruce D. Gelb², Ronald A. Li^1,3, Nicole C. Dubois², Kevin D. Costa^{1 1}Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, ²The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, ³Stem Cell & Regenerative Medicine Consortium, LKS Faculty of Medicine, University of Hong Kong This manuscript describes the creation of defined engineered cardiac tissues using surface marker expression and cell sorting. The defined tissues can then be used in a multi-tissue bioreactor to investigate mechanisms of cardiac cell therapy in order to provide a functional, yet controlled, model system of the human heart.

• Biology

  
  High Efficiency Differentiation of Human Pluripotent Stem Cells to Cardiomyocytes and Characterization by Flow Cytometry Subarna Bhattacharya*¹, Paul W. Burridge*², Erin M. Kropp¹, Sandra L. Chuppa¹, Wai-Meng Kwok³, Joseph C. Wu², Kenneth R. Boheler^4,5, Rebekah L. Gundry^{1,6 1}Department of Biochemistry, Medical College of Wisconsin, ²Stanford Cardiovascular Institute, Stanford University School of Medicine, ³Department of Anesthesiology, Medical College of Wisconsin, ⁴Stem Cell and Regenerative Medicine Consortium, LKS Faculty of Medicine, Hong Kong University, ⁵Division of Cardiology, Johns Hopkins University School of Medicine, ⁶Cardiovascular Research Center, Biotechnology and Bioengineering Center, Medical College of Wisconsin The article describes the detailed methodology to efficiently differentiate human pluripotent stem cells into cardiomyocytes by selectively modulating the Wnt pathway, followed by flow cytometry analysis of reference markers to assess homogeneity and identity of the population.

• Neuroscience

  
  Morphometric Analyses of Retinal Sections Tin Fung Chan¹, Kin Chiu¹, Carmen Ka Ming Lok¹, Wing Lau Ho¹, Kwok-Fai So^1,2,3, Raymond Chuen-Chung Chang^{1,2,3 1}Laboratory of Neurodegenerative Diseases, Department of Anatomy, LKS Faculty of Medicine, The University of Hong Kong, ²Research Centre of Heart, Brain, Hormone and Healthy Aging, LKS Faculty of Medicine, The University of Hong Kong, ³State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong This video demonstrates three types of morphometric analyses of the retina, which include measuring the inner nuclear layer thickness, quantifying the number of retinal ganglion cells (RGCs) and measuring the sizes of RGCs. The technique can offer a simple but scientific platform for morphometric analyses.

• Biology

  
  Retrograde Labeling of Retinal Ganglion Cells by Application of Fluoro-Gold on the Surface of Superior Colliculus Kin Chiu¹, Wui-Man Lau¹, Sze-chun Yeung¹, Raymond Chuen-Chung Chang¹, Kwok-Fai So^{1 1}The University of Hong Kong - HKU This video describes the method of retrograde labeling of RGC by applying fluoro-gold (FG) on the surface of superior colliculus (SC). Technique involves drilling the skull, aspirating the cortex, and applying gelatin sponge over entire dorsal surface of SC.

• Biology

  
  Laser-Induced Chronic Ocular Hypertension Model on SD Rats Kin Chiu¹, Raymond Chang¹, Kwok-Fai So^{1 1}Laboratory of Neurodegenerative Diseases, Department of Anatomy, LKS Faculty of Medicine, The University of Hong Kong - HKU Glaucoma is one of the major causes of blindness in the world. Elevated intraocular pressure is a major risk factor. Laser photocoagulation induced ocular hypertension is one of the well established animal models. This video demonstrates how to induce ocular hypertension by Argon laser photocoagulation in rat.

• Biology

  
  Intravitreous Injection for Establishing Ocular Diseases Model Kin Chiu¹, Raymond Chuen-Chung Chang¹, Kwok-Fai So^{1 1}The University of Hong Kong - HKU Intravitreous injection is a widely used technique in visual sciences research for ocular diseases or as direct application of local treatment. This video demonstrated a protocol for intravitreous injection using a 1ml syringe with glass pipette. Useful tips about avoiding massive bleeding and lens damage are given.

• Biology

  
  Micro-dissection of Rat Brain for RNA or Protein Extraction from Specific Brain Region Kin Chiu¹, Wui Man Lau¹, Ho Tak Lau¹, Kwok-Fai So¹, Raymond Chuen-Chung Chang^{1 1}Laboratory of Neurodegenerative Diseases, Department of Anatomy, LKS Faculty of Medicine, The University of Hong Kong - HKU Micro-dissection of rat brain into various regions is extremely important for the study of different neurodegenerative diseases. This video demonstrates micro-dissection of four major brain regions include olfactory bulb, frontal cortex, striatum and hippocampus in fresh rat brain tissue. Useful tips for quick removal of respective regions to avoid RNA and protein degradation of the tissue are given.