JoVE Clinical and Translational Medicine
Epidural Intracranial Pressure Measurement in Rats Using a Fiber-optic Pressure Transducer
Biomedical Sciences and Pharmacy, The University of Newcastle
A novel technique to record the pressures within the skull is described. The minimally invasive method uses a fibre-optic pressure sensing system to accurately measure intracranial pressure (ICP) in anaesthetized rats without causing significant brain trauma. The technique may be used in a wide range of experimental models.
JoVE Bioengineering
Integrated Photoacoustic Ophthalmoscopy and Spectral-domain Optical Coherence Tomography
1Department of Biomedical Engineering, Northwestern University, 2Department of Physics, Harbin Institute of Technology, 3Department of Ophthalmology, University of Southern California, 4Department of Ophthalmology, Northwestern University
Photoacoustic ophthalmology (PAOM), an optical-absorption-based imaging modality, provides the complementary evaluation of the retina to the currently available ophthalmic imaging technologies. We report the using of PAOM integrated with spectral-domain optical coherence tomography (SD-OCT) for simultaneous multimodal retinal imaging in rats.
JoVE General
The Preparation of Drosophila Embryos for Live-Imaging Using the Hanging Drop Protocol
Department of Biology, University of Waterloo
A simple, inexpensive, and effective method of preparing Drosophila embryos for live-imaging analysis is presented. Our protocol provides humidity and gas exchange and does not compress the Drosophila embryo. This method is suitable for GFP-based live imaging of Drosophila embryos using a stereomicroscope or upright compound microscope.
JoVE Clinical and Translational Medicine
Corneal Confocal Microscopy: A Novel Non-invasive Technique to Quantify Small Fibre Pathology in Peripheral Neuropathies
Division of Cardiovascular Medicine, University of Manchester
Corneal Confocal microscopy is a non-invasive clinical technique which may be used to quantify C fibre damage to diagnose and stratify patients with increasing neuropathic severity.
JoVE Bioengineering
Postproduction Processing of Electrospun Fibres for Tissue Engineering
1Materials Science and Engineering, University of Sheffield, 2Department of Biomedical Science, University of Sheffield, 3Department of Chemistry, University of Sheffield
Electrospun scaffolds can be processed post production for tissue engineering applications. Here we describe methods for spinning complex scaffolds (by consecutive spinning), for making thicker scaffolds (by multi-layering using heat or vapour annealing), for achieving sterility (aseptic production or sterilisation post production) and for achieving appropriate biomechanical properties.
JoVE Applied Physics
Fabrication of Silica Ultra High Quality Factor Microresonators
1Department of Chemical Engineering and Materials Science, University of Southern California, 2Department of Electrical Engineering-Electrophysics, University of Southern California
We describe the use of a carbon dioxide laser reflow technique to fabricate silica resonant cavities, including free-standing microspheres and on-chip microtoroids. The reflow method removes surface imperfections, allowing long photon lifetimes within both devices. The resulting devices have ultra high quality factors, enabling applications ranging from telecommunications to biodetection.
JoVE Clinical and Translational Medicine
Optimized System for Cerebral Perfusion Monitoring in the Rat Stroke Model of Intraluminal Middle Cerebral Artery Occlusion
Department of Neuroscience and Biomedical Technologies, University of Milano Bicocca
Cerebral perfusion monitoring has been demonstrated to improve accuracy in ischemic stroke models. Technical difficulties often limit the use of this essential tool for cerebrovascular research. In this video, an optimized system is shown to obtain a single or multi-site hemodynamic monitoring during intraluminal middle cerebral artery occlusion in rats.
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 Bioengineering
High-resolution Fiber-optic Microendoscopy for in situ Cellular Imaging
1Department of Bioengineering, Rice University, 2Department of Molecular and Cellular Oncology, The Univeristy of Texas M. D. Anderson Cancer Center
In many biological and clinical situations it is advantageous to study cellular processes as they evolve in their native microenvironment. Here we describe the assembly and use of a low-cost fiber-optic microscope which can provide real time imaging in cell culture, animal studies, and clinical patient studies.
JoVE Neuroscience
Paired Patch Clamp Recordings from Motor-neuron and Target Skeletal Muscle in Zebrafish
Vollum Institute, Oregon Health and Sciences University
Larval zebrafish represent the first vertebrate model system to allow simultaneous patch clamp recording from a spinal motor-neuron and target skeletal muscle. This video demonstrates the microscopic methods used to identify a segmental CaP motor-neuron and target muscle cells as well as the methodologies for recording from each cell type.
JoVE Neuroscience
Electrophysiological Recordings from the Giant Fiber Pathway of D. melanogaster
1Institute of Healthy Ageing, and GEE, University College London - UCL, 2School of Biosciences, University of Kent
The Giant Fiber System is a simple neuronal circuit of adult Drosophila melanogaster containing the largest neurons in the fly. We describe the protocol for monitoring synaptic transmission through this pathway by recording post synaptic potentials in dorsal longitudinal (DLM) and tergotrochanteral (TTM) muscles following direct stimulation of the Giant Fiber interneurons.
JoVE General
A Reversible, Non-invasive Method for Airway Resistance Measurements and Bronchoalveolar Lavage Fluid Sampling in Mice
1Department of Medicine, Baylor College of Medicine (BCM), 2Millenium Premier Group, 3Department of Immunology, Baylor College of Medicine (BCM)
Repeated measurements of rodent respiratory physiology and sampling of airway inflammatory cells are desirable, but generally not feasible. Here we describe a repeatable method for orally intubating mice that permits repeated measurements of airway hyperreactivity and sampling of airway inflammatory cells.
JoVE Applied Physics
Fabricating Metamaterials Using the Fiber Drawing Method
Institute of Photonics and Optical Sciences (IPOS), School of Physics, University of Sydney
Metamaterials at terahertz frequencies offer unique opportunities, but are challenging to fabricate in bulk. We adapt the fabrication procedure for microstructured polymer optical fibers to inexpensively fabricate metamaterials potentially on an industrial scale. We produce polymethylmethacrylate fibers containing ~10 μm diameter indium wires separated by ~100 μm, which exhibit a terahertz plasmonic response.
JoVE Immunology and Infection
Imaging Leukocyte Adhesion to the Vascular Endothelium at High Intraluminal Pressure
Vascular Pharmacology Laboratory, Baker IDI Heart and Diabetes Institute, Monash University
This is a method to visualise leukocyte adhesion to the endothelium in harvested pressurised vessels. The technique enables studying vascular adhesion under shear flow with differing intraluminal pressures up to 200 mmHg thus mimic-ing the pathophysiological conditions of high blood pressure.
JoVE Applied Physics
Bringing the Visible Universe into Focus with Robo-AO
1Caltech Optical Observatories, California Institute of Technology, 2Department of Astronomy, California Institute of Technology, 3Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 4Inter-University Centre for Astronomy & Astrophysics, 5Observatories of the Carnegie Institution for Science, 6Benoziyo Center for Astrophysics, Weizmann Institute of Science
Light from astronomical objects must travel through the earth's turbulent atmosphere before it can be imaged by ground-based telescopes. To enable direct imaging at maximum theoretical angular resolution, advanced techniques such as those employed by the Robo-AO adaptive-optics system must be used.
JoVE Clinical and Translational Medicine
MRI-guided Disruption of the Blood-brain Barrier using Transcranial Focused Ultrasound in a Rat Model
1Imaging Research, Sunnybrook Research Institute, 2Department of Medical Biophysics, University of Toronto, 3Department of Medical Biophysics, and Institute of Biomaterials & Biomedical Engineering (IBBME), University of Toronto
Microbubble-mediated focused ultrasound disruption of the blood-brain barrier (BBB) is a promising technique for non-invasive targeted drug delivery in the brain1-3. This protocol outlines the experimental procedure for MRI-guided transcranial BBB disruption in a rat model.
JoVE Applied Physics
Hyperpolarized Xenon for NMR and MRI Applications
ERC Project BiosensorImaging, Leibniz-Institut für Molekulare Pharmakologie
The production of hyperpolarized xenon by means of spin exchange optical pumping (SEOP) is described. This method yields a ~10000-fold enhancement of the nuclear spin polarization of Xe-129 and has applications in nuclear magnetic resonance spectroscopy and imaging. Examples of gas phase and solution state experiments are given.
JoVE Clinical and Translational Medicine
Murine Echocardiography and Ultrasound Imaging
1Department of Pharmacology and Physiology, University of Rochester, 2Aab Cardiovascular Research Institute, University of Rochester, 3Visualsonics, 4Department of Medicine, University of Rochester
This video demonstrates use of a rail-mounted high-frequency ultrasound probe to perform echocardiography on an anesthetized mouse. The methods describe both conventional two-dimensional and M-mode measurements of cardiac function in addition to newer, more powerful tools such as color Doppler, strain analysis, as well as general and targeted contrast imaging.
JoVE General
Agrobacterium-Mediated Virus-Induced Gene Silencing Assay In Cotton
1Department of Biochemistry and Biophysics, Institute of Plant Genomics and Biotechnology, Texas A&M University, 2Department of Plant Pathology and Microbiology, Institute of Plant Genomics and Biotechnology, Texas A&M University
We present the detailed protocol for Agrobacterium-mediated virus-induced gene silencing (VIGS) assay in cotton. The tobacco rattle virus (TRV)-derived VIGS vectors were deployed to induce RNA silencing of cotton GrCLA1, Cloroplastos alterados 1 gene. The albino phenotype caused by silencing GrCLA1 was observed at the seedling stage within 2 weeks after inoculation.
JoVE General
Semi-automated Optical Heartbeat Analysis of Small Hearts
1Development and Aging Program, The Sanford Burnham Institute for Medical Research, 2Cardiac Electrophysiology Group, Dept. of Physiology, Anatomy and Genetics, The Sanford Burnham Institute for Medical Research, 3Biology Department and Heart Institute, San Diego State University
We have developed a Semi-automated Optical Heartbeat Analysis method (SOHA) for analyzing high speed optical recordings from Drosophila, zebrafish and embryonic mouse hearts. We demonstrate the application of our methodology to the analysis of heart function in fruit fly and embryonic mouse hearts.
JoVE Neuroscience
Functional Neuroimaging Using Ultrasonic Blood-brain Barrier Disruption and Manganese-enhanced MRI
1Department of Radiology, Stanford University, 2Center for In Vivo Microscopy, Duke University Medical Center, 3Department of Biomedical Engineering, Duke University
A technique is described for broadly opening the blood-brain barrier in the mouse using microbubbles and ultrasound. Using this technique, manganese can be administered to the mouse brain. Because manganese is an MRI contrast agent that accumulates in depolarized neurons, this approach enables imaging of neuronal activity.
JoVE Neuroscience
Optogenetic Activation of Zebrafish Somatosensory Neurons using ChEF-tdTomato
Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles
Optogenetic techniques have made it possible to study the contribution of specific neurons to behavior. We describe a method in larval zebrafish for activating single somatosensory neurons expressing a channelrhodopsin variant (ChEF) with a diode-pumped solid state (DPSS) laser and recording the elicited behaviors with a high-speed video camera.
JoVE Clinical and Translational Medicine
Assessment of Cardiac Function and Energetics in Isolated Mouse Hearts Using 31P NMR Spectroscopy
Department of Anesthesiology & Pain Medicine, University of Washington School of Medicine
Langendorff-mode isolated heart perfusion, in conjunction with 31P NMR spectroscopy, combines the fields of biochemistry and physiology into one experiment. The protocol allows for the dynamic measurement of high energy phosphate content and turnover in the heart while concurrently monitoring physiologic function. When performed correctly, this is a valuable technique in the assessment of cardiac energetics.
JoVE Neuroscience
An Optic Nerve Crush Injury Murine Model to Study Retinal Ganglion Cell Survival
1National Eye Institute, NIH, 2Ophthalmology Department, The Second Hospital of Harbin Medical University
This protocol shows how to retrogradely label retinal ganglion cells, and how to subsequently make an optic nerve crush injury in order to analyze retinal ganglion cell survival and apoptosis. It is an experimental disease model for different types of optic neuropathy, including glaucoma.
JoVE Bioengineering
Measuring Left Ventricular Pressure in Late Embryonic and Neonatal Mice
1Department of Biomedical Engineering, Saint Louis University, 2Department of Internal Medicine, Washington University School of Medicine
Measuring left ventricular pressure (LV) in embryonic and neonatal mice is described. Pressure is measured by inserting a needle connected to a fluid-filled transducer into the LV under ultrasound guidance. Care must be taken to maintain normal cardiac function during the experimental protocol.
JoVE Clinical and Translational Medicine
In vitro Measurements of Tracheal Constriction Using Mice
Department of Physiology, UT Health Science Center, San Antonio
Transgenic mice have been extremely useful in ascribing physiological function to genes. As such, research in general, and functional studies of airway, in particular, have undergone a remarkable shift toward murine models. Here we provide protocols for in vitro trachea constriction studies to evaluate smooth muscle function in murine airway.
JoVE Bioengineering
Introduction to the Ultrasound Targeted Microbubble Destruction Technique
Department of Medicine, JABSOM, University of Hawaii
Ultrasound Targeted Microbubble Destruction (UTMD) can be used to direct site-specific delivery of bioactive molecules, including therapeutic genes, to target organs accessible to ultrasound, such as the heart and liver1-6.
JoVE Bioengineering
Detection and Isolation of Circulating Melanoma Cells using Photoacoustic Flowmetry
We have developed a flow cytometer using laser induced ultrasound to detect circulating melanoma cells as an early indicator of metastatic disease.
JoVE Neuroscience
Extracellularly Identifying Motor Neurons for a Muscle Motor Pool in Aplysia californica
1Department of Biology, Case Western Reserve University, 2Department of Neurosciences, Case Western Reserve University, 3Department of Biomedical Engineering, Case Western Reserve University
In animals with large identified neurons (e.g. mollusks), analysis of motor pools is done using intracellular techniques1,2,3,4. Recently, we developed a technique to extracellularly stimulate and record individual neurons in Aplysia californica5. We now describe a protocol for using this technique to uniquely identify and characterize motor neurons within a motor pool.
JoVE Clinical and Translational Medicine
Fixed Volume or Fixed Pressure: A Murine Model of Hemorrhagic Shock
Department of Surgery, University of Pittsburgh
The Hemorrhagic Shock model has been a reliable and reproducible resource facilitating the identification and understanding of signaling cascades associated with inflammation and end-organ damage after trauma. This article provides a step-by-step description of surgical and mechanical aspects associated with the Hemorrhagic Shock experimental procedure in mice.
JoVE General
Optical Scatter Microscopy Based on Two-Dimensional Gabor Filters
Department of Biomedical Engineering, Rutgers University
We demonstrate a dark-field microscopy method based on Gabor-like filtering to measure subcellular dynamics within single living cells. The technique is sensitive to alterations in the structure of organelles, such as mitochondrial fragmentation.
JoVE Neuroscience
Physiological Experimentation with the Crayfish Hindgut: A Student Laboratory Exercise
1Department of Biology, University of Kentucky, 2Department of Biological Sciences, Brock University
In this report we demonstrate techniques that can be used to investigate the biology of the crayfish hindgut. We show how to dissect a crayfish abdomen and study the associated anatomy, physiology and modulation of activity. The peristaltic activity and strength of contractions are measured using a force transducer.
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 General
Microsurgical Clip Obliteration of Middle Cerebral Aneurysm Using Intraoperative Flow Assessment
Department of Neurosurgery , Havard Medical School, Massachusetts General Hospital
Description of the surgical obliteration of a cerebral aneurysm utilizing an ultrasonic flow probe to assess arterial flow prior to and after aneurysm clip placement.
JoVE Neuroscience
Methods for Experimental Manipulations after Optic Nerve Transection in the Mammalian CNS
Department of Surgery, University of Toronto
Optic Nerve transection is a widely used model of adult CNS injury. This model is ideal for performing a number of experimental manipulations that target the retina globally or directly target the injured neuronal population of retinal ganglion cells.
JoVE Neuroscience
C. elegans Positive Butanone Learning, Short-term, and Long-term Associative Memory Assays
1Department of Molecular Biology, Lewis-Sigler Institute for Integrative Genomics, Princeton University, 2Lewis-Sigler Institute for Integrative Genomics, Princeton University
Here we describe methods to test C. elegans associative learning and short- and long-term associative memory. These population assays employ the worms abilities to chemotax toward volatile odorants, and form positive associations upon pairing food with the chemoattractant butanone. Increasing the number of conditioning periods induces long-term memory.
JoVE Clinical and Translational Medicine
In Vivo Canine Muscle Function Assay
1Department of Neurology and Wake Forest Institute for Regenerative Medicine, Wake Forest University, 2Department of Human Nutrition, Foods and Exercise, Virginia Polytechnic Institute and State University, 3Departments of Pathology and Laboratory Medicine and Neurology and the Gene Therapy Center , University of North Carolina-Chapel Hill
We describe a minimally-invasive and painless method to measure canine hindlimb muscle strength and muscle response to repeated eccentric contractions.
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 Neuroscience
Optic Nerve Transection: A Model of Adult Neuron Apoptosis in the Central Nervous System
Department of Surgery, University of Toronto
Optic Nerve transection is a widely used model of adult CNS injury. Ninety percent of retinal ganglion cells (RGCs) whose axons are completely transected (axotomy) die within 14 days after axotomy. This model is easily amenable to experimental manipulations and highly reproducible.
JoVE General
Characterization of the Isolated, Ventilated, and Instrumented Mouse Lung Perfused with Pulsatile Flow
Department of Biomedical Engineering, University of Wisconsin – Madison
The following protocol outlines the process of isolating, ventilating and instrumenting mouse lungs to measure steady or pulsatile pulmonary vascular pressure-flow relationships in order to quantify the effects of blood flow, airflow, airway changes and vascular changes on right ventricular afterload.
JoVE Clinical and Translational Medicine
Murine Fetal Echocardiography
Fetal and perinatal death is a common feature when studying genetic alterations affecting cardiac development. High-frequency ultrasound imaging has improved 2-D resolution and can provide excellent information on early cardiac development and is an ideal method to detect the impact on cardiac structure and function prior to death.
JoVE Neuroscience
Single-unit In vivo Recordings from the Optic Chiasm of Rat
Department of Biomedical Engineering, Boston University
Retinal ganglion cells transmit visual information from the eye to the brain with sequences of action potentials. Here, we demonstrate how to record the action potentials of single ganglion cells in vivo from anesthetized rats.
JoVE Bioengineering
Micropipette Aspiration of Substrate-attached Cells to Estimate Cell Stiffness
1Section of Respiratory, Critical Care and Sleep Medicine, Department of Medicine, University of Illinois, 2Institute for Medicine and Engineering, University of Pennsylvania
Here we describe a quick and simple method to measure cell stiffness. The general principle of this approach is to measure membrane deformation in response to well-defined negative pressure applied through a micropipette to the cell surface. This method provides a powerful tool to study biomechanical properties of substrate-attached cells.
JoVE General
Fluorescent Labeling of Drosophila Heart Structures
1Biology Department, San Diego State University, 2Development and Aging Program, NASCR Center, The Sanford Burnham Institute for Medical Research
Here we describe a basic protocol for fluorescent labeling of different elements of heart tubes from larva and adult Drosophila melanogaster. These specimens are well-suited for imaging via fluorescent or confocal microscopy. This technique permits detailed structural analysis of the features of the hearts from a powerful model organism.
JoVE Neuroscience
Progenitor-derived Oligodendrocyte Culture System from Human Fetal Brain
1Laboratory of Molecular Medicine and Neuroscience, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 2Laboratory of Neurophysiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health
Primary, human fetal brain-derived, multipotential progenitor cells proliferate in vitro while maintaining the capacity to differentiate into neurons and astrocytes. This work shows that neural progenitors can be induced to differentiate through stages of the oligodendrocytic lineage by conditioning with select growth factors.
JoVE Clinical and Translational Medicine
Myo-mechanical Analysis of Isolated Skeletal Muscle
1Cardiovascular Research Institute, University of California San Francisco, 2Department of Pediatrics, University of California San Francisco, 3Department of Biology, San Francisco State University, 4Department of Medicine, University of California San Francisco, 5Eli and Edythe Broad Center of Regeneration Medicine & Stem Cell Research, University of California San Francisco
To assess the in vivo effects of therapeutic interventions for muscle disease, methods are needed to quantitate force generation and fatigability in treated muscle. We detail an approach to evaluating myo-mechanical properties in explanted mouse hindlimb muscle. This analysis provides a robust approach to quantitating the effects of genetic modification on muscle function, as well as comparison of therapies in mouse models of muscle disease.
JoVE Bioengineering
Engineering Biological-Based Vascular Grafts Using a Pulsatile Bioreactor
1Department of Biomedical Engineering, Yale University, 2Department of Anesthesiology, Yale University School of Medicine
Our group has developed a bioreactor culture system that mimics the physiological pulsatile stresses of the cardiovascular system to regenerate implantable small-diameter vascular grafts.
JoVE Clinical and Translational Medicine
Direct Pressure Monitoring Accurately Predicts Pulmonary Vein Occlusion During Cryoballoon Ablation
1Department of Cardiac Electrophysiology, Piedmont Heart Institute, 2Cardiac Rhythm, Medtronic Inc.
Effective pulmonary vein isolation utilizing a cryoballoon depends on complete pulmonary vein occlusion. The point of occlusion can be effectively predicted by direct analysis of pulmonary vein pressure waveform analysis during balloon inflation using a simple and reproducible technique.
JoVE Clinical and Translational Medicine
NADH Fluorescence Imaging of Isolated Biventricular Working Rabbit Hearts
1Electrical and Computer Engineering Department, The George Washington University, 2Pharmacology and Physiology Department, The George Washington University
The objective is to monitor the mitochondrial redox state of isolated hearts within the context of physiologic preload and afterload pressures. A biventricular working rabbit heart model is presented. High spatiotemporal resolution fluorescence imaging of NADH is used to monitor the mitochondrial redox state of epicardial tissue.
JoVE Neuroscience
Fiber-optic Implantation for Chronic Optogenetic Stimulation of Brain Tissue
1Department of Molecular & Human Genetics, Baylor College of Medicine (BCM), 2Department of Neuroscience, Baylor College of Medicine (BCM), 3Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital
The development of optogenetics now provides the means to precisely stimulate genetically defined neurons and circuits, both in vitro and in vivo. Here we describe the assembly and implantation of a fiber optic for chronic photostimulation of brain tissue.
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