JoVE Clinical and Translational Medicine
Dorsal Column Steerability with Dual Parallel Leads using Dedicated Power Sources: A Computational Model
Boston Scientific , Neuromodulation
Using a mathematical model of spinal cord stimulation, we found that a multi-source system with independent power sources for each contact can target more central points of stimulation on the dorsal column (100 vs 3) and has 50-fold more field steering resolution (0.02mm vs 1mm) than a single-source system.
JoVE Applied Physics
Construction of a High Resolution Microscope with Conventional and Holographic Optical Trapping Capabilities
Department of Physics and Astronomy, University of Utah
The system described herein employs a traditional optical trap as well as an independent holographic optical trapping line, capable of creating and manipulating multiple traps. This allows for the creation of complex geometric arrangements of refractive particles while also permitting simultaneous high-speed, high-resolution measurements of the activity of biological enzymes.
JoVE Bioengineering
Magnetically-Assisted Remote Controlled Microcatheter Tip Deflection under Magnetic Resonance Imaging
1Department of Radiology and Biomedical Imaging, University of California, San Francisco, 2School of Medicine, University of California, San Francisco, 3Department of Radiology and Biomedical Imaging, UCSF Medical Center, 4University of California, San Francisco, 5Hansen Medical, Mountain View, CA
Current applied to an endovascular microcatheter with microcoil tip made by laser lathe lithography can achieve controllable deflections under magnetic resonance (MR) guidance, which may improve speed and efficacy of navigation of vasculature during various endovascular procedures.
JoVE Bioengineering
Rejection of Fluorescence Background in Resonance and Spontaneous Raman Microspectroscopy
1Center for Biophotonics Science and Technology, University of California, Davis, 2Department of Pathology and Laboratory Medicine, University of California, Davis
We discuss the construction and operation of a complex nonlinear optical system that uses ultrafast all-optical switching to isolate Raman from fluorescence signals. Using this system we are able to successfully separate Raman and fluorescence signals utilizing pulse energies and average powers that remain biologically safe.
JoVE Clinical and Translational Medicine
Driving Simulation in the Clinic: Testing Visual Exploratory Behavior in Daily Life Activities in Patients with Visual Field Defects
1Department of Neurology, Universitätsmedizin Charité, 2Center for Stroke Research Berlin (CSB), Universitätsmedizin Charité, 3Berlin School of Mind and Brain, Humboldt Universität zu Berlin
Patients with visual deficits after stroke report about different constraints in daily life most likely due to variable compensatory strategies, which are difficult to differentiate in clinical routine. We present a clinical set-up which allows measurement of different compensatory head- and eye-movement-strategies and evaluating their effects on driving performance.
JoVE General
Isolation and Culture of Cells from the Nephrogenic Zone of the Embryonic Mouse Kidney
1Department of Molecular Medicine, Maine Medical Center Research Institute, 2Molecular Medicine and Gene Therapy, Lund University Hospital
In this report we describe a method for the isolation and culture of the progenitor cell niche from the embryonic mouse kidney that can be used to study signaling pathways regulating stem/progenitor cells of the developing kidney. These cultured cells are highly accessible to small molecule and recombinant protein treatment, and importantly also to viral transduction, which allows efficient manipulation of candidate pathways.
JoVE Neuroscience
Combining Computer Game-Based Behavioural Experiments With High-Density EEG and Infrared Gaze Tracking
1Department of Human Development, Cornell University, 2Social Sciences Division, University of Chicago, 3National Brain Research Centre, Manesar, India
Procedures for recording high-density EEG and gaze data during computer game-based cognitive tasks are described. Using a video game to present cognitive tasks enhances ecological validity without sacrificing experimental control.
JoVE Editorial
September 2012: This Month in JoVE
1Department of Ophthalmology, Massachusetts Eye and Ear, 2JoVE Content Production
This September in JoVE, researchers from the School of Medicine at the Free University of Berlin demonstrate a novel method for studying how stroke patients compensate for visual field defects. To do this, our authors make use of a driving simulator complete with brakes, a steering wheel, and turn signals. Using driving simulation software and sophisticated eye tracking, researchers can compare the gaze behavior of stroke patients as they navigate through virtual driving courses with varying degrees of complexity. Though posterior cerebral artery infarction can lead to similar visual deficits in patients, some are able to navigate through the driving courses by developing compensatory eye movements, while others crash into dangerous obstacles, like wild boars. Through the analysis of compensatory gaze behavior employed by patients, our authors see great potential for using driving simulation as a tool to rehabilitate stroke patients trying to overcome the blind spots in their visual fields.
JoVE Bioengineering
Constructing a Low-budget Laser Axotomy System to Study Axon Regeneration in C. elegans
Department of Biology, University of Utah
Laser axotomy followed by time-lapse imaging is a sensitive way to assay the effects of mutations in C. elegans on axon regeneration. A high quality, but inexpensive, laser ablation system can be easily added to most microscopes. Time lapse imaging over 15 hours requires careful immobilization of the worm.
JoVE Clinical and Translational Medicine
Remote Magnetic Navigation for Accurate, Real-time Catheter Positioning and Ablation in Cardiac Electrophysiology Procedures
1Cardiology, Robotic Cardiac Electrophysiology and Arrhythmia Unit, La Paz University Hospital, 2Magnetecs Corp., 3Cardiology, Geffen School of Medicine at UCLA Los Angeles
This report provides a detailed description of a new remote navigation system based on magnetic driven forces, which has been recently introduced as a new robotic tool for human cardiac electrophysiology procedures.
JoVE General
Neuronal Cell Cultures from Aplysia for High-Resolution Imaging of Growth Cones
Department of Biological Sciences, Purdue University
Aplysia californica neurons develop large growth cones in culture that are excellent for high-resolution imaging of growth cone motility and guidance. Here, we present a protocol for dissection and plating of Aplysia bag cell neurons as well as for setting up a chamber for live cell imaging.
JoVE Bioengineering
Quantitative Locomotion Study of Freely Swimming Micro-organisms Using Laser Diffraction
1Physics & Astronomy Department, Vassar College, 2Biology Department, Vassar College
Microscopic organisms like the free-swimming nematode C. elegans, live and behave in a complex three-dimensional environment. We report on a novel approach that provides analysis of C. elegans using diffraction patterns. This approach consists of tracking the temporal periodicity of diffraction patterns generated by directing laser light through a cuvette.
JoVE Bioengineering
Video-rate Scanning Confocal Microscopy and Microendoscopy
1Program in Biophysics, Harvard University, 2Division of Health Sciences and Technology, Harvard-MIT, 3Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School
The complete construction of a custom, real-time confocal scanning imaging system is described. This system, which can be readily used for video-rate microscopy and microendoscopy, allows for an array of imaging geometries and applications not accessible using standard commercial confocal systems, at a fraction of the cost.
JoVE Applied Physics
Determining 3D Flow Fields via Multi-camera Light Field Imaging
1Department of Mechanical Engineering, Brigham Young University, 2Naval Undersea Warfare Center, Newport, RI
A technique for performing quantitative three-dimensional (3D) imaging for a range of fluid flows is presented. Using concepts from the area of Light Field Imaging, we reconstruct 3D volumes from arrays of images. Our 3D results span a broad range including velocity fields and multi-phase bubble size distributions.
JoVE Neuroscience
An Experimental Platform to Study the Closed-loop Performance of Brain-machine Interfaces
Department of Bioengineering, Imperial College London
We use a closed-loop fly-machine interface to investigate general principles in neuronal control.
JoVE Neuroscience
Automated Interactive Video Playback for Studies of Animal Communication
1Department of Visualization, Texas A&M University (TAMU), 2Department of Biology, Texas A&M University (TAMU)
Video playback is a widely used technique in animal behavior. We created and evaluated a program that applies rules-based, interactive playback of 3-D computer animations in response to real-time, automated data on subject behavior.
JoVE Bioengineering
Contrast Ultrasound Targeted Treatment of Gliomas in Mice via Drug-Bearing Nanoparticle Delivery and Microvascular Ablation
1Department of Biomedical Engineering, University of Virginia, 2Neurological Surgery , University of Virginia
Insonation of microbubbles is a promising strategy for tumor ablation at reduced time-averaged acoustic powers, as well as for the targeted delivery of therapeutics. The purpose of the present study is to develop low duty cycle ultrasound pulsing strategies and nanocarriers to maximize non-thermal microvascular ablation and payload delivery to subcutaneous C6 gliomas.
JoVE Neuroscience
Investigations on Alterations of Hippocampal Circuit Function Following Mild Traumatic Brain Injury
1Division of Neurology, Children's Hospital of Philadelphia, 2Neuroscience Graduate Group, Perelman School of Medicine at the University of Pennsylvania, 3Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania
A multi-faceted approach to investigating functional changes to hippocampal circuitry is explained. Electrophysiological techniques are described along with the injury protocol, behavioral testing and regional dissection method. The combination of these techniques can be applied in similar fashion for other brain regions and scientific questions.
JoVE Bioengineering
A Microfluidic-based Hydrodynamic Trap for Single Particles
1Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, 2Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign
In this article, we present a microfluidic-based method for particle confinement based on hydrodynamic flow. We demonstrate stable particle trapping at a fluid stagnation point using a feedback control mechanism, thereby enabling confinement and micromanipulation of arbitrary particles in an integrated microdevice.
JoVE General
Assembly, Tuning and Use of an Apertureless Near Field Infrared Microscope for Protein Imaging
1Department of Chemistry, University of Toronto, 2Department of Chemistry, University of Wisconsin, 3Department of Chemistry, Duke University
The assembly of a nearfield infrared microscope for imaging protein aggregates is described.
JoVE General
Monitoring Dynamic Changes In Mitochondrial Calcium Levels During Apoptosis Using A Genetically Encoded Calcium Sensor
Department of Neuroscience and Cell Biology, University of Texas Medical Branch
This protocol describes a method for real-time measurement of mitochondrial calcium fluxes by fluorescent imaging. The method takes advantage of a circularly permutated YFP-based dual-excitation ratiometric calcium sensor (ratiometric pericam-mt) selectively expressed in mitochondria.
JoVE Bioengineering
Low-Cost Cryo-Light Microscopy Stage Fabrication for Correlated Light/Electron Microscopy
Department of Molecular and Cellular Biology, University of California Davis
We demonstrate the fabrication of a low-cost cryogenic stage designed to fit most reflected light microscopes. This lab-built cryogenic stage enables efficient and reliable correlative imaging between cryo-light and cryo-electron microscopy.
JoVE General
Atmospheric-pressure Molecular Imaging of Biological Tissues and Biofilms by LAESI Mass Spectrometry
Department of Chemistry, George Washington University
Laser ablation electrospray ionization (LAESI) is an atmospheric-pressure ion source for mass spectrometry. In the imaging mode, a mid-infrared laser probes the distributions of molecules across a tissue section or a biofilm. This technique presents a new approach for diverse bioanalytical studies carried out under native experimental conditions.
JoVE General
Direct Analysis of Single Cells by Mass Spectrometry at Atmospheric Pressure
Department of Chemistry, George Washington University
Single cell analysis is performed by mass spectrometry on plant and animal cells at atmospheric pressure by using a sharpened optical fiber to sample the cells for laser ablation electrospray ionization (LAESI) mass spectrometry.
JoVE Bioengineering
Stretching Short Sequences of DNA with Constant Force Axial Optical Tweezers
1LSA Biophysics, University of Michigan, 2LSA Biophysics, Department of Physics, University of Michigan
We illustrate the use of a constant force axial optical tweezers to explore the mechanical properties of short DNA molecules. By stretching DNA axially, we minimize steric hindrances and artifacts arising in conventional lateral manipulation, allowing us to study DNA molecules as short as ~100 nm.
JoVE Clinical and Translational Medicine
Catheter Ablation in Combination With Left Atrial Appendage Closure for Atrial Fibrillation
Department of Cardiology, St. Antonius Hospital, The Netherlands
Catheter ablation is combined with placement of the WATCHMAN Left Atrial Appendage Closure Device to prevent ischemic stroke in a patient with non-valvular atrial fibrillation.
JoVE General
Brain Slice Stimulation Using a Microfluidic Network and Standard Perfusion Chamber
1Dept. of Bioengineering, University of Illinois, Chicago, 2Department of Anatomy and Cell Biology, University of Illinois, Chicago
We demonstrate fabrication of a simple microfluidic device that can be integrated with standard electrophysiology setups to expose microscale surfaces of a brain slice in a well controlled manner to different neurotransmitters.
JoVE Neuroscience
A Galvanotaxis Assay for Analysis of Neural Precursor Cell Migration Kinetics in an Externally Applied Direct Current Electric Field
1Institute for Biomaterials and Biomedical Engineering, University of Toronto, 2Lyndhurst Centre, Toronto Rehabilitation Institute, 3Department of Surgery, University of Toronto
In this protocol we demonstrate how to construct custom chambers that permit the application of a direct current electric field to enable time-lapse imaging of adult brain derived neural precursor cell translocation during galvanotaxis.
JoVE General
Introducing an Angle Adjustable Cutting Box for Analyzing Slice Shear Force in Meat
1Lacombe Research Centre, Agriculture and Agri-Food Canada, 2Grupo de investigación MERAGEM, Universidad de Córdoba, 3Department of Animal Science, University of Nebraska
Slice shear force is a reference method for beef texture analysis. Using an angle adjustable cutting box could increase its accuracy for research purposes. The results from different locations within the longissimus muscle show a high correlation with Warner-Bratzler shear force methodology and high potential adaptability for different muscles.
JoVE General
Knowing What Counts: Unbiased Stereology in the Non-human Primate Brain
1Department of Physiology, University of Montreal, 2Ecole d’optometrie, University of Montreal, 3Stereology Resource Center
The anatomical organization of the primate brain can provide important insights into normal and pathological conditions in humans. Unbiased stereology is a method for accurately and efficiently estimating the total neuron number (or other cell type) in a given reference space1.
JoVE Neuroscience
Morphometric Analyses of Retinal Sections
1Laboratory 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.
JoVE General
Long-term Imaging Mammalian Cells using Wide-Field Microscopy
Dept. of Cell Biology, Harvard Medical School
JoVE General
Deficient Pms2, ERCC1, Ku86, CcOI in Field Defects During Progression to Colon Cancer
1Department of Cell Biology and Anatomy, College of Medicine, University of Arizona, Tucson, 2Southern Arizona Veterans Affairs Health Care System, Tucson, AZ, 3Department of Surgery, College of Medicine, University of Arizona, Tucson, 4Biomedical Diagnostics and Research, Tucson, AZ, 5Department of Medicine, College of Medicine, University of Arizona, Tucson
Reduced/absent expression of Pms2 and/or ERCC1 in entire crypts is a frequent event within 10 cm on each side of colonic adenocarcinomas, likely the basis of a field defect with high mutability and progression to cancer. Deficiency in Ku86 or CcOI is much less frequent in these field defects.
JoVE Immunology and Infection
Avian Influenza Surveillance with FTA Cards: Field Methods, Biosafety, and Transportation Issues Solved
1Resource Ecology Group, Wageningen University, 2Section for Zoonotic Ecology and Epidemiology, School of Natural Sciences, Linnaeus University, 3Centre for Wildlife Ecology, Simon Fraser University
A method to preserve, detect and sequence RNA from Avian Influenza Viruses was validated and extended using natural faecal samples from birds. This technique removes the necessity of maintaining a cool chain and handling of infectious viruses and can be applied in a 96-well high-throughput setup.
JoVE Immunology and Infection
Detection of Infectious Virus from Field-collected Mosquitoes by Vero Cell Culture Assay
We describe a method to process and screen field-collected mosquitoes for a diversity of viruses by Vero cell culture assay. By employing this technique, we have detected 9 different viruses from 4 taxonomic families in mosquitoes collected in Connecticut.
JoVE Bioengineering
Electric Field-controlled Directed Migration of Neural Progenitor Cells in 2D and 3D Environments
1School of Dentistry, Cardiff Institute of Tissue Engineering & Repair, Cardiff University, 2Shandong Qianfoshan Hospital, Shandong University School of Medicine, 3Dermatology and Ophthalmology Research, Institute for Regenerative Cures, University of California at Davis
This protocol demonstrates methods used to establish 2D and 3D environments in custom-designed electrotactic chambers, which can track cells in vivo/ex vivo using time-lapse recording at the single cell level, in order to investigate galvanotaxis/electrotaxis and other cellular responses to direct current (DC) electric fields (EFs).
JoVE Clinical and Translational Medicine
The Use of Primary Human Fibroblasts for Monitoring Mitochondrial Phenotypes in the Field of Parkinson's Disease
1German Center for Neurodegenerative Diseases, DZNE, 2Laboratory of Functional Neurogenomics, Department of Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research, University of Tübingen
Fibroblasts from patients carrying mutations in Parkinson's disease-causing genes represent an easily accessible ex vivo model to study disease-associated phenotypes. Live cell imaging gives the opportunity to study morphological and functional parameters in living cells. Here we describe the preparation of human fibroblasts and subsequent monitoring of mitochondrial phenotypes.
JoVE Applied Physics
Development of Whispering Gallery Mode Polymeric Micro-optical Electric Field Sensors
Mechanical Engineering Department, Southern Methodist University
A high-sensitivity photonic micro sensor was developed for electric field detection. The sensor exploits the optical modes of a dielectric sphere. Changes in the external electric field perturb the sphere morphology leading to shifts in its optical modes. The electric field strength is measured by monitoring these optical shifts.
JoVE Bioengineering
Wide-field Fluorescent Microscopy and Fluorescent Imaging Flow Cytometry on a Cell-phone
1Electrical Engineering Department, University of California, Los Angeles, 2Bioengineering Department, University of California, Los Angeles, 3California NanoSystems Institute (CNSI), University of California, Los Angeles
We review our recent results on the integration of fluorescent microscopy and imaging flow cytometry tools on a cell-phone using compact and cost-effective opto-fluidic attachments. These cell-phone based micro-analysis devices might be useful for cytometric analysis, such as performing various cell counting tasks as well as for high-throughput screening of e.g., water samples in resource limited settings.
JoVE Bioengineering
Lensless Fluorescent Microscopy on a Chip
Department of Electrical Engineering, University of California, Los Angeles
A lensless on-chip fluorescent microscopy platform is demonstrated that can image fluorescent objects over an ultra-wide field-of-view of e.g., >0.6-8 cm2 with <4μm resolution using a compressive sampling based decoding algorithm. Such a compact and wide-field fluorescent on-chip imaging modality could be valuable for high-throughput cytometry, rare-cell research and microarray-analysis.
JoVE Bioengineering
Simultaneous Synthesis of Single-walled Carbon Nanotubes and Graphene in a Magnetically-enhanced Arc Plasma
Department of Mechanical and Aerospace Engineering, The George Washington University
Anodic arc discharge is one of the most practical and efficient methods to synthesize various carbon nanostructures. To increase the arc controllability and flexibility, a non-uniform magnetic field was introduced to process the one-step synthesis of large-scale graphene flakes and high-purity single-walled carbon nanotubes.
JoVE General
Preparation of Highly Coupled Rat Heart Mitochondria
1Faculty of Life Sciences, University of Manchester, 2School of Biological Sciences, Queen's University Belfast
We describe а protocol for isolation of pure, highly coupled rat heart mitochondria for functional or structural studies of cellular bioenergetics, biophysical measurements, proteomics or mitochondrial DNA and lipids analysis.
JoVE Immunology and Infection
A Simple Chelex Protocol for DNA Extraction from Anopheles spp.
1Malaria Institute at Macha, 2Department of Molecular Microbiology & Immunology, Johns Hopkins Bloomberg School of Public Health
A rapid and affordable way to extract quality malaria parasite and vector DNA from mosquito specimens is described. Capitalizing on chelating properties of Chelex resin, the simple method enables genotyping of malaria parasites in mosquito mid-gut and salivary gland phases, as well as molecular identification of the Anopheles sibling species by PCR.
JoVE Immunology and Infection
Colonization of Euprymna scolopes Squid by Vibrio fischeri
Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University
The method outlines the procedure by which the Hawaiian bobtail squid, Euprymna scolopes and its bacterial symbiont, Vibrio fischeri, are raised separately and then introduced to allow for specific colonization of the squid light organ by the bacteria. Colonization detection by bacterially-derived luminescence and by direct colony counting are described.
JoVE Immunology and Infection
Engineering and Evolution of Synthetic Adeno-Associated Virus (AAV) Gene Therapy Vectors via DNA Family Shuffling
1Cluster of Excellence CellNetworks, Department of Infectious Diseases, Virology, Heidelberg University, 2Department of Infectious Diseases, Virology, Heidelberg University
We demonstrate the basic technique to molecularly engineer and evolve synthetic Adeno-associated viral (AAV) gene therapy vectors via DNA family shuffling. Moreover, we provide general guidelines and representative examples for selection and analysis of individual chimeric capsids with enhanced properties on target cells in culture or in mice.
JoVE General
A Simple Protocol for Extracting Hemocytes from Wild Caterpillars
Department of Biological Sciences, The George Washington University
Insect hemocytes carry out many important functions, both immune and non-immune, throughout all stages of insect development. Our present knowledge of hemocyte types and function comes from studies on insect genetic models. Here, we present a method for extracting, quantifying and visualizing hemocytes from wild caterpillars.
JoVE General
RNA-seq Analysis of Transcriptomes in Thrombin-treated and Control Human Pulmonary Microvascular Endothelial Cells
Children's Mercy Hospital and Clinics, School of Medicine, University of Missouri-Kansas City
This protocol presents a complete and detailed procedure to apply RNA-seq, a powerful next-generation DNA sequencing technology, to profile transcriptomes in human pulmonary microvascular endothelial cells with or without thrombin treatment. This protocol is generalizable to various cells or tissues affected by different reagents or disease states.
JoVE General
Measuring the Induced Membrane Voltage with Di-8-ANEPPS
Department of Biomedical Engineering, Faculty of Electrical Engineering, University of Ljubljana
External electric field induces a voltage on the membrane of a cell, termed the induced membrane voltage (ΔΦ). By using the potentiometric dye di-8-ANEPPS, it is possible to measure the ΔΦ noninvasively. This video shows the protocol for measuring ΔΦ using di-8-ANEPPS.
JoVE Bioengineering
Fluorescence detection methods for microfluidic droplet platforms
1Department of Chemistry, Imperial College London, 2Department of Biochemistry, Protein Chip Research Center, Chungbuk National University, 3Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich
Droplet-based microfluidic platforms are promising candidates for high throughput experimentation since they are able to generate picoliter, self-compartmentalized vessels inexpensively at kHz rates. Through integration with fast, sensitive and high resolution fluorescence spectroscopic methods, the large amounts of information generated within these systems can be efficiently extracted, harnessed and utilized.
JoVE Clinical and Translational Medicine
Changing the Direction and Orientation of Electric Field During Electric Pulses Application Improves Plasmid Gene Transfer in vitro
1Department of Fundamentals of Electrical Engineering, Mathematics and Physics, University of Ljubljana, 2Department of Biomedical Engineering, University of Ljubljana
Gene transfection by electroporation is improved approximately two times when orientation of electric field is changed during pulse application, while cell viability is not affected. The increase in gene transfection is caused by the increase of the membrane area which is made competent for DNA entry into the cell.
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