JoVE General
Isometric and Eccentric Force Generation Assessment of Skeletal Muscles Isolated from Murine Models of Muscular Dystrophies
1Department of Anatomy and Cell Biology, School of Dental Medicine, University of Pennsylvania, 2Department of Physiology, Perelman School of Medicine, University of Pennsylvania, 3Department of Anatomy and Cell Biology, School of Dental Medicine, School of Dental Medicine, University of Pennsylvania
Muscle function measurements contribute to the evaluation of potential therapeutics for muscle pathology, as well as to the determination of mechanisms underlying physiology of this tissue. We will demonstrate the preparation of the extensor digitorum longus and diaphragm muscles for functional testing. Protocols for isometric and eccentric contractions will be shown, as well as differences in results between dystrophic muscles, representing a pathological state, and wildtype muscles.
JoVE Applied Physics
Concurrent Quantitative Conductivity and Mechanical Properties Measurements of Organic Photovoltaic Materials using AFM
1Center for Nanoscale Materials, Argonne National Laboratory, 2Institute for Molecular Engineering, University of Chicago
Organic photovoltaic (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale inhomogeneity of OPV materials affects performance of photovoltaic devices. In this paper, we describe a protocol for quantitative measurements of electrical and mechanical properties of OPV materials with sub-100 nm resolution.
JoVE General
Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles
1Department of Physiology and Biophysics, UMDNJ-Robert Wood Johnson Medical School, 2Muscle Biology Research Group, University of Missouri-Kansas City, 3Pharmacology division, College of Pharmacy, DHLRI, Ohio State University
We describe a method to directly measure muscle force, muscle power, contractile kinetics and fatigability of isolated skeletal muscles in an in vitro system using field stimulation. Valuable information on Ca2+ handling properties and contractile machinery of the muscle can be obtained using different stimulating protocols.
JoVE General
Procedures for Rat in situ Skeletal Muscle Contractile Properties
Faculty of Kinesiology, University of Calgary
This video demonstrates the surgical preparation and procedures needed to study the contractile responses of the rat medial gastrocnemius muscle preparation in situ. This preparation allows measurement of skeletal muscle contractile properties under physiological conditions. The animal is anesthetized and the muscle is separated from surrounding tissue at its distal end. The Achilles tendon is attached to a force transducer, allowing measurement of the muscle’s contractile response at 37 degrees C with an intact circulation.
JoVE General
Micro-Mechanical Characterization of Lung Tissue Using Atomic Force Microscopy
The stiffness of the extracellular matrix strongly influences multiple behaviors of adherent cells. Matrix stiffness varies spatially throughout a tissue, and undergoes modification in various disease conditions. Here we develop methods to characterize spatial variations in stiffness in normal and fibrotic mouse lung tissue using atomic force microscopy microindentation.
JoVE General
A Tactile Automated Passive-Finger Stimulator (TAPS)
1Department of Occupational Therapy, Duquesne University, 2Department of Psychology, Neuroscience and Behaviour, McMaster University
We describe a computer-controlled device for investigating the sense of touch: the Tactile Automated Passive-finger Stimulator (TAPS). We describe the components of TAPS, and show how TAPS is used to administer a two-interval forced-choice tactile grating orientation test.
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 Neuroscience
Mechanical Manipulation of Neurons to Control Axonal Development
Department of Zoology, Michigan State University, East Lansing
Application and direct measurements of forces on neurons in the 2-1000 microdyne range are achieved with high precision using calibrated glass needles. This methodology can be used to control and measure several aspects of axonal development, including axonal initiation, axonal tension, velocity of axonal elongation, and force vectors.
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 General
Measuring the Bending Stiffness of Bacterial Cells Using an Optical Trap
1Department of Molecular Biology, Lewis-Sigler Institute for Integrative Genomics, Princeton University, 2Department of Physics, Lewis-Sigler Institute for Integrative Genomics, Princeton University
We present a protocol for bending filamentous bacterial cells attached to a cover-slip surface with an optical trap to measure the cellular bending stiffness.
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
Multiplexed Single-molecule Force Proteolysis Measurements Using Magnetic Tweezers
Department of Chemical Engineering, Stanford University
In this article we describe the use of magnetic tweezers to study the effect of force on enzymatic proteolysis at the single molecule level in a highly parallelizable manner.
JoVE Bioengineering
Demonstrating the Uses of the Novel Gravitational Force Spectrometer to Stretch and Measure Fibrous Proteins
Department of Biological Sciences, University of North Texas
This is a step-by step guide showing the purpose, operation, and representative results from the novel gravitational force spectrometer.
JoVE Bioengineering
Encapsulation of Cardiomyocytes in a Fibrin Hydrogel for Cardiac Tissue Engineering
Department of Biomedical Engineering, Tufts University
We describe the isolation of neonatal cardiomyocytes and the preparation of the cells for encapsulation in fibrin hydrogel constructs for tissue engineering. We describe methods for analyzing the tissue engineered myocardium after the culture period including active force generated upon electrical stimulation and cell viability and immunohistological staining.
JoVE Neuroscience
Kinematics and Ground Reaction Force Determination: A Demonstration Quantifying Locomotor Abilities of Young Adult, Middle-aged, and Geriatric Rats
1CullenWebb Animal Neurology & Ophthalmology Center, Riverview, NB, 2Department of Clinical Neurosciences, Faculty of Medicine, University of Calgary, 3Department of Comparative Biology and Experimental Medicine, University of Calgary, 4Department of Neuroscience, University of Calgary
Locomotion is often examined as a behavioural outcome in various models of disease in fields such as neuroscience and orthopedics. This video paper intends to describe a method for collecting ground reaction forces and kinematics from rats during unrestrained locomotion.
JoVE Neuroscience
One Dimensional Turing-Like Handshake Test for Motor Intelligence
Biomedical Engineering, Ben-Gurion University
We present a Turing-like Handshake test administered through a telerobotic system in which the interrogator is holding a robotic stylus and interacting with another party (human or artificial). We use a forced choice method, and extract a measure for the similarity of the artificial model to a human handshake.
JoVE Bioengineering
Separating Beads and Cells in Multi-channel Microfluidic Devices Using Dielectrophoresis and Laminar Flow
1Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, 2Micro and Nanotechnology Lab, University of Illinois at Urbana-Champaign, 3Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 4Bioengineering, University of Illinois at Urbana-Champaign
Dielectrophoresis (DEP) is an effective method to manipulate cells. Printed circuit boards (PCB) can provide inexpensive, reusable and effective electrodes for contact-free cell manipulation within microfluidic devices. By combining PDMS-based microfluidic channels with coverslips on PCBs, we demonstrate bead and cell manipulation and separation within multichannel microfluidic devices.
JoVE Neuroscience
Behavioral Assessment of Manual Dexterity in Non-Human Primates
Department of Medicine, University of Fribourg
As manual dexterity is a prerogative mainly of primates, behavioral tasks have been developed in macaque monkeys. Four reach and grasp prehension tasks, measuring hand manipulation ability and force, allow to establish functional recovery after a lesion of the central nervous system and to test the effect of a treatment.
JoVE Clinical and Translational Medicine
A Contusive Model of Unilateral Cervical Spinal Cord Injury Using the Infinite Horizon Impactor
1International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 2Department of Orthopaedics, University of British Columbia
A reliable and repeatable way to produce a cervical unilateral spinal cord injury using the Infinite Horizon impactor is described. The method takes advantage of a custom designed frame and clamp to stabilize the spine. The standardized procedure and biomechanical injury parameters result in sufficient and sustained injuries.
JoVE Bioengineering
Mechanical Testing of Mouse Carotid Arteries: from Newborn to Adult
Department of Biomedical Engineering, Saint Louis University
Passive mechanical testing of mouse carotid arteries is described, with special consideration for adapting to different specimen ages. The procedures include determining the in vivo length of the artery, mounting it in a pressure myograph, recording data, measuring the unloaded dimensions and analyzing the resulting data.
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 General
Evaluation of Muscle Function of the Extensor Digitorum Longus Muscle Ex vivo and Tibialis Anterior Muscle In situ in Mice
Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri
Changes in limb muscle contractile and passive mechanical properties are important biomarkers for muscle diseases. This manuscript describes physiological assays to measure these properties in the murine extensor digitorum longus and tibialis anterior muscles.
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 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 Clinical and Translational Medicine
Acute and Chronic Tactile Sensory Testing after Spinal Cord Injury in Rats
1Center for Brain and Spinal Cord Repair, School of Allied Medical Professions, The Ohio State University, 2Spinal Cord Research Center, Drexel University College of Medicine
We describe two tactile sensory testing methods for acute or chronic periods of spinal cord injury in rats. These validated procedures can detect the development and maintenance of allodynia-like sensations.
JoVE Editorial
April 2013: This Month in JoVE
1Department of Ophthalmology, Massachusetts Eye and Ear, 2JoVE Content Production
Here are some highlights from the April 2013 Issue of Journal of Visualized Experiments (JoVE).
JoVE General
Microfabricated Post-Array-Detectors (mPADs): an Approach to Isolate Mechanical Forces
1Department of Bioengineering, University of Pennsylvania, 2University of Washington
In this video, we demonstrate how to fabricate and utilize microfabricated post array detectors (mPADs) to assess modulations of cellular contractility.
JoVE Clinical and Translational Medicine
Mesenteric Artery Contraction and Relaxation Studies Using Automated Wire Myography
1Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, 2Department of Biology, North Carolina Central University, Durham, 3Department of Physiology & Pharmacology and Hypertension & Vascular Research Center, Wake Forest University School of Medicine
An automated myography method for force measurements in isolated mesenteric arteries is described. It employs a Mulvany-Halpern Auto Dual Wire Myograph 510A to determine responses to phenylephrine and extracellular calcium. The method allows consistent determination of isometric responses to agonists in small vessels of diameters of 60 - 300 μm, independently.
JoVE Neuroscience
Simultaneous Intracellular Recording of a Lumbar Motoneuron and the Force Produced by its Motor Unit in the Adult Mouse In vivo
Department of Physiology, Northwestern University Feinberg School of Medicine
This new method permits the simultaneous intracellular recording of a single adult mouse motoneuron and the measurement of the force produced by its muscle fibers. The combined investigation of the electrical and mechanical properties of motor units in normal and genetically modified animals is a breakthrough for the study of the neuromuscular system.
JoVE Bioengineering
Haptic/Graphic Rehabilitation: Integrating a Robot into a Virtual Environment Library and Applying it to Stroke Therapy
1Department of Bioengineering, University of Illinois at Chicago and Rehabilitation Institute of Chicago, 2Sensory Motor Performance Program, Rehabilitation Institute of Chicago
Recently, a vast amount of prospects have come available for human-robot interactive systems. In this paper we outline the integration of a new robotic device with open source software that can rapidly make possible a library of interactive functionality. We then outline a clinical application for a neurorehabilitation application.
JoVE Immunology and Infection
Measurement of Tactile Allodynia in a Murine Model of Bacterial Prostatitis
Department of Urology, Northwestern University Feinberg School of Medicine
Infection of the prostate may be a contributing factor in mediating pelvic pain in chronic prostatitis. We describe the procedure for preparation of standardized bacterial inoculum, instillation of bacteria into the urethra of male mice and methodology for measuring tactile allodynia in mice over time.
JoVE Bioengineering
Bacterial Immobilization for Imaging by Atomic Force Microscopy
1Biological and Nanoscale Systems Group, Biosciences Division, Oak Ridge National Laboratory, 2Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, 3Department of Surgery, Eastern Virginia Medical School, 4Center for Nanophase Materials Sciences Division, Oak Ridge National Laboratory
Live Gram-negative and Gram-positive bacteria can be immobilized on gelatin-coated mica and imaged in liquid using Atomic Force Microscopy (AFM).
JoVE Clinical and Translational Medicine
An Investigation of the Effects of Sports-related Concussion in Youth Using Functional Magnetic Resonance Imaging and the Head Impact Telemetry System
1Graduate Department of Rehabilitation Science, University of Toronto, 2Occupational Science and Occupational Therapy, University of Toronto, 3Department of Psychology, University of Toronto, 4Bloorview Kids Rehab, 5Toronto Rehab, 6Cognitive Neurology, Sunnybrook Health Sciences Centre, 7Faculty of Medicine, University of Toronto
This article provides an overview of a multi-modal approach to mild traumatic brain injury diagnosis and recovery in youth. This approach combines neuropsychological testing with functional magnetic resonance imaging and the Head Impact Telemetry System to monitor the relationship between head impacts and brain activity during cognitive testing.
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 Bioengineering
Measurement of Aggregate Cohesion by Tissue Surface Tensiometry
Department of Surgery, UMDNJ-Robert Wood Johnson Medical School
We describe a method of measuring binding energy, expressible as tissue surface tension, between cells within 3D tissue-like aggregates. Differences in tissue surface tension have been demonstrated to correlate with invasiveness of lung, muscle, and brain tumors, and are fundamental determinants of establishing spatial relationships between different cell types.
JoVE Clinical and Translational Medicine
An in vivo Rodent Model of Contraction-induced Injury and Non-invasive Monitoring of Recovery
1Department of Physiology, University of Maryland School of Medicine, 2Department of Orthopaedics, University of Maryland School of Medicine, 3Department of Diagnostic Radiology, University of Maryland School of Medicine
An in vivo animal model of injury is described. The method takes advantage of the subcutaneous position of the fibular nerve. Velocity, timing of muscle activation, and arc of motion are all pre-determined and synchronized using commercial software. Post injury changes are monitored in vivo using MR imaging/spectroscopy.
JoVE Bioengineering
Quantifying the Mechanical Properties of the Endothelial Glycocalyx with Atomic Force Microscopy
Department of Biomedical Engineering, University of Rochester
The mechanical characteristics of endothelial glycocalyx were measured by indentation using micron sized spheres on AFM cantilevers. Endothelial cells were cultured in a custom chamber under physiological flow conditions to induce glycocalyx expression. Data were analyzed using a thin film model to determine the glycocalyx thickness and modulus.
JoVE Immunology and Infection
The Insect Galleria mellonella as a Powerful Infection Model to Investigate Bacterial Pathogenesis
Oral and intra haemocolic infection of larvae of the greater wax moth Galleria mellonella is described. This insect can be used to study virulence factors of entomopathogenic as well as mammalian opportunistic bacteria. Rearing of the insects, methods of infection and examples of in vivo analysis are described.
JoVE General
Direct Observation of Enzymes Replicating DNA Using a Single-molecule DNA Stretching Assay
We describe a method for observing real time replication of individual DNA molecules mediated by proteins of the bacteriophage replication system.
JoVE Applied Physics
Micropunching Lithography for Generating Micro- and Submicron-patterns on Polymer Substrates
Mechanical and Aerospace Engineering, University of Texas at Arlington
A micropunching lithography approach is developed to generate micro- and submicron-patterns on top, sidewall and bottom surfaces of polymer substrates. It overcomes the obstacles of patterning conducting polymers and generating sidewall patterns. This method allows rapid fabrication of multiple features and is free of aggressive chemistry.
JoVE General
Measuring Plant Cell Wall Extension (Creep) Induced by Acidic pH and by Alpha-Expansin
Department of Biology, Penn State University
We demonstrate the use of a constant-force extensometer to measure long-term extension (creep) of plant cell wall specimens induced by acidic buffers and expansin protein.
JoVE General
Using Laser Tweezers For Manipulating Isolated Neurons In Vitro
This video describes the manipulation of cultured neurons using laser tweezers in vitro.
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 Bioengineering
Adhesion Frequency Assay for In Situ Kinetics Analysis of Cross-Junctional Molecular Interactions at the Cell-Cell Interface
Biomedical Engineering Department, Georgia Institute of Technology
An adhesion frequency assay for measuring receptor-ligand interaction kinetics when both molecules are anchored on the surfaces of the interacting cells is described. This mechanically-based assay is exemplified using a micropipette-pressurized human red blood cell as adhesion sensor and integrin αLβ2 and intercellular adhesion molecule-1 as interacting receptors and ligands.
JoVE Bioengineering
In vitro Synthesis of Native, Fibrous Long Spacing and Segmental Long Spacing Collagen
1Department of Chemistry, University of Toronto, 2Institute for Optical Sciences, University of Toronto
Simple and reproducible procedures are described for making three structurally distinct collagen assemblies from a common commercially available Type I collagen monomer. Native type, fibrous long spacing or segmental long spacing collagen can be constructed by varying the conditions to which the 300 nm long and 1.4 nm diameter monomer building block is exposed.
JoVE General
Live Cell Response to Mechanical Stimulation Studied by Integrated Optical and Atomic Force Microscopy
1Department of Systems Biology and Translational Medicine, College of Medicine, Cardiovascular Research Institute, Texas A&M Health Science Center, 2Department of Biomedical Engineering, Texas A&M University
This paper aims to instruct the reader in the operation of an integrated atomic force-optical imaging microscope for mechanical stimulation of live cells in culture. A step-by-step protocol is presented. A representative data set that shows live cell response to mechanical stimulation is presented.
JoVE Bioengineering
Preparation of Complaint Matrices for Quantifying Cellular Contraction
1Institute for Biophysical Dynamics, University of Chicago, 2Physics Department - James Franck Institute, University of Chicago, 3Interdisciplinary Scientist Training Program, University of Chicago
In this video, we demonstrate the experimental techniques used to fabricate compliant, extracellular matrix (ECM) coated substrates suitable for cell culture, and which are amenable to traction force microscopy and observing effects of ECM stiffness on cell behavior.
JoVE General
Biophysical Assays to Probe the Mechanical Properties of the Interphase Cell Nucleus: Substrate Strain Application and Microneedle Manipulation
1Brigham and Women's Hospital / Harvard Medical School, Department of Medicine, Cardiovascular Division, 2Weill Institute for Cell and Molecular Biology & Department of Biomedical Engineering, Cornell University
We present two independent, microscope-based tools to measure the induced nuclear and cytoskeletal deformations in single, living adherent cells in response to global or localized strain application. These techniques are used to determine nuclear stiffness (i.e., deformability) and to probe intracellular force transmission between the nucleus and the cytoskeleton.
JoVE Bioengineering
Live-cell Imaging of Migrating Cells Expressing Fluorescently-tagged Proteins in a Three-dimensional Matrix
University of California, Davis
Cellular processes such as cell migration have traditionally been studied on two-dimensional, stiff plastic surfaces. This report describes a technique for directly visualizing protein localization and analyzing protein dynamics in cells migrating in a more physiologically relevant, three-dimensional matrix.
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.
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