<h2 class="jove_title"><a href="https://www.jove.com/video/3445">MALDI Imaging Mass Spectrometry of Neuropeptides in Parkinson's Disease</a></h2>
J&#246;rg Hanrieder1, 2, Anna Ljungdahl1, Malin Andersson1 1Department of Pharmaceutical Biosciences, Uppsala University, 2Department of Chemical and Biological Engineering, Chalmers University of Technology
Dopamine replacement pharmacotherapy using L-DOPA is the most commonly used symptomatic treatment of Parkinson's disease, but is accompanied by side effects including involuntary abnormal movements, termed dyskinesia 1. Here, a protocol for MALDI imaging mass spectrometry is presented that detects changes in rat brain neuropeptide levels related to dyskinesia.
<h2 class="jove_title"><a href="https://www.jove.com/video/3466">Detection of Microregional Hypoxia in Mouse Cerebral Cortex by Two-photon Imaging of Endogenous NADH Fluorescence</a></h2>
Oksana Polesskaya1, Anita Sun2, Gheorghe Salahura2, Jharon N. Silva1, Stephen Dewhurst1, Karl Kasischke3 1Department of Microbiology and Immunology, University of Rochester Medical Center, 2Center for Neural Development and Disease, University of Rochester Medical Center, 3Deptartment of Neurology, Center for Neural Development and Disease, University of Rochester Medical Center 
Here we describe a method to directly visualize microregional tissue hypoxia in the mouse cortex in vivo. It is based on concurrent two-photon imaging of nicotinamide adenine dinucleotide (NADH) and the cortical microcirculation. This method is useful for high resolution analysis of tissue oxygen supply.
<h2 class="jove_title"><a href="https://www.jove.com/video/3661">MAME Models for 4D Live-cell Imaging of Tumor: Microenvironment Interactions that Impact Malignant Progression</a></h2>
Mansoureh Sameni1, Arulselvi Anbalagan1, Mary B. Olive1, Kamiar Moin1, 2, Raymond R. Mattingly1, 2, Bonnie F. Sloane1, 2 1Department of Pharmacology, Wayne State University , 2Barbara Ann Karmanos Cancer Institute, Wayne State University 
We have developed 3D coculture models for live-cell imaging in real-time of interactions among breast tumor cells and other cells in their microenvironment that impact progression to an invasive phenotype. These models can serve as preclinical screens for drugs to target paracrine-induced proteolytic, chemokine/cytokine and kinase pathways implicated in invasiveness.
<h2 class="jove_title"><a href="https://www.jove.com/video/3671">The WATCHMAN Left Atrial Appendage Closure Device for Atrial Fibrillation</a></h2>
Sven M&#246;bius-Winkler, Marcus Sandri, Norman Mangner, Phillip Lurz, Ingo D&#228;hnert, Gerhard Schuler University of Leipzig Heart Center
The accompanying video describes a procedure for percutaneous placement of the WATCHMAN Left Atrial Appendage (LAA) Device. The WATCHMAN is a nitinol device designed to be permanently implanted at, or slightly distal to, the opening of the left atrial appendage (LAA) to trap blood clots before they exit the LAA, preventing thromboembolic stroke.
<h2 class="jove_title"><a href="https://www.jove.com/video/3756">Measuring Left Ventricular Pressure in Late Embryonic and Neonatal Mice</a></h2>
Victoria P. Le1, Attila Kovacs2, Jessica E. Wagenseil1 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.
<h2 class="jove_title"><a href="https://www.jove.com/video/3888">In vitro Mesothelial Clearance Assay that Models the Early Steps of Ovarian Cancer Metastasis</a></h2>
Rachel A. Davidowitz, Marcin P. Iwanicki, Joan S. Brugge Department of Cell Biology, Harvard Medical School
The mesothelial clearance assay described here takes advantage of fluorescently labeled cells and time-lapse video microscopy to visualize and quantitatively measure the interactions of ovarian cancer multicellular spheroids and mesothelial cell monolayers. This assay models the early steps of ovarian cancer metastasis.
<h2 class="jove_title"><a href="https://www.jove.com/video/3894">Saliva, Salivary gland, and Hemolymph Collection from Ixodes Scapularis Ticks</a></h2>
Toni G. Patton1, Gabrielle Dietrich2, Kevin Brandt1, Marc C. Dolan2, Joseph Piesman2, Robert D. Gilmore Jr.1 1Microbiology and Pathogenesis Activity, Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 2Tick-Borne Diseases Activity, Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention
The collection of infected tick hemolymph, salivary glands, and saliva is important to study how tick-borne pathogens cause disease. In this protocol we demonstrate how to collect hemolymph and salivary glands from feeding Ixodes scapularis nymphs. We also demonstrate saliva collection from female I. scapularis adults.
<h2 class="jove_title"><a href="https://www.jove.com/video/3750">A New Single Chamber Implantable Defibrillator with Atrial Sensing: A Practical Demonstration of Sensing and Ease of Implantation</a></h2>
Dietmar B&#228;nsch, Ralph Schneider, Ibrahim Akin, Cristoph A. Nienaber Heart Center Rostock, University Hospital of Rostock, Germany
Dual-chamber implantable cardioverter-defibrillators (ICDs) may improve detection of atrial fibrillation as well as differentiation of tachycardias. However, this advantage is undermined by complications associated with the second electrode, which is required in conventional dual chamber devices. Therefore, BIOTRONIK has developed a new electrode called the LinoxSMART S DX that, when used in conjunction with the Lumax DX ICD, offers dual-chamber detection without the risks associated with the second electrode.

Aucun conflit d&#39;intérêt déclaré.

february 2012: this month in jove

The February issue of the Journal of Visualized Experiments (JoVE) takes a clinical theme with the release of two articles, which demonstrate implantations of medical devices used to treat cardiac arrhythmia. More specifically, both articles focus on treating atrial fibrillation - a devastating condition that can ultimately lead to stroke.
The first procedure, led by Professor Dietmar Baensch from the University Hospital Rostock, involves the surgical implantation of an implantable cardioverter-defibrillator, or ICD. ICDs are devices widely used for the termination of ventricular arrhythmias. However, if the site of abnormal pacemaking is supraventricular in origin, such as in the left atrium, these devices can deliver inappropriate and painful shocks. To overcome this issue with potential misdiagnosis, as well as higher complication rates observed with dual chamber elecectrodes, Biotronik has developed a single ICD lead, which is capable of both atrial and ventricular sensing. Guided by X-ray fluoroscopy and electrophysiology, Dr. Baensch and his team demonstrate the surgical procedure for inserting, testing, and anchoring the single chamber electrode. Following electrode positioning, the Lumax defibrillator is joined to the electrode and inserted into the patient. To assess device function ventricular fibrillation is induced via a T-wave shock, and the ability of the defibrillator to sense arrhythmia and administer a corrective shock to is assessed.
While the Lumax ICD system can attenuate cardiac arrhythmia by correcting cardiac pacemaking, the WATCHMAN left atrial appendage (LAA) occlusion device from Boston Scientific is designed to address a severe complication with atrial fibrillation - thromboembolic stroke. In patients with atrial fibrillation, the left atrial appendage, a muscular pouch in the left atrium, can act as a reservoir for clotting blood, which if dislodged, can form emboli that can cause stroke. When implanted, the WATCHMAN device can trap clots within the LAA before they exit. Following assessment of LAA morphology, our authors, led by Dr. Sven M&ouml;bius-Winkler from the University of Leipzig, demonstrate methods for inserting a guidewire through the femoral artery into the heart, advancing the device into the left atrium, and deployment of the device in the left atrial appendage. Studies have shown that patients receiving WATCHMAN intervention have a reduced probability of adverse cardiac events when compared to patients given the anticoagulant medication warfarin.
While both the Lumax ICD system and the WATCHMAN occlusion device show promise for treating cardiac arrhythmia and its complications, neither device is approved for use in the US. Through video-publication in JoVE, our authors have provided a resource for US physicians to view these sensitive device implantation procedures before they become available across the Atlantic.
One consequence of thromboembolism is hypoxia, and JoVE travels to the University of Rochester to document a method for 2-photon imaging of microregional hypoxia in the cerebral cortex. Our authors illustrate a detailed open cranial window preparation followed by 2-photon imaging of endogenous nicotinamide adenine dinucleotide, or NADH, fluorescence. NADH is well known for its ability to transport electrons during cellular respiration, and it just so happens that NADH fluorescence exhibits a nonlinear relationship with the partial pressure of oxygen in tissues. In the cortex, NADH fluorescence increases as hypoxia is induced, allowing these investigators to determine which cortical areas are most vulnerable to hypoxia, as well as the geometrical pattern of oxygen diffusion from vessels.
For Bioengineering, JoVE heads to Wayne State University to capture a procedure for visualizing the breast cancer tumor microenvironment, in vitro. Our authors demonstrate a procedure for the assembly of a breast cancer co-culture system, which they refer to as Mammary Architecture and Microenvironment Engineering, or MAME. Briefly, these culture models consist of a layer of human breast fibroblasts in collagen 1 matrix, below a layer of reconstituted basement membrane matrix, upon which ductal carcinoma cells from the breast are added before the entire model is submerged in medium. When imaged in 4D, or in 3 dimensions over time, the proliferation of carcinoma cells can be tracked. In addition, degradation of the basement membrane can be assessed as well, thanks to the incorporation of a type of collagen that fluoresces when hydrolyzed. This innovative culture system can provide insight for breast cancer researchers into the proteolytic pathways that promote invasive phenotypes in breast cancer cells and can be used to screen for new small molecule inhibitors that may hinder tumor proliferation.
In Immunology and Infection, JoVE shifts its focus to vector borne disease, where investigators from the Center for Disease control in Fort Collins, Colorado, present three fundamentally important procedures for understanding how infectious pathogens migrate through the tick. The first procedure involves removing one of the legs from the tick, which enables the collection of hemolymph - the fluid carries oxygen to the tick's organs. The bacteria that cause Lyme Disease, Borrelia burgdorferi, will move to the hemolymph of the tick once a bloodmeal has been absorbed by the midgut. The second dissection protocol illustrates steps for accessing the hemocoel and removing the salivary glands, which is where Borrrelia reside before transmission to a host. The final protocol begins with application of the muscarinic agonist, pilocarpine, to the dorsal surface of an engorged tick, in order to induce salivation. Saliva is collected from a mouthpart referred to as the hypostome and manual techniques for promoting tick salivation via gentle massage, are demonstrated.
From vector borne disease to medical device implantation, February is brimming with content submitted from authors dedicated to understanding and treating human disease. Other notable articles for the month of February include methods for assessing the metastatic potential of ovarian cancer, spatial analysis of neuropeptides in a rodent model of Parkinson's, and measurements of ventricular pressure in neonatal and embryonic mice. From bench to bedside, no other journal provides a window into biomedical research quite like JoVE. Stay tuned for February's content!

Watch this Scientific Journal Video about February 2012: This Month in JoVE at JoVE.com

February 2012: This Month in JoVE

Février 2012: Ce mois-ci dans JoVE

The February issue of the Journal of Visualized Experiments (JoVE) takes a clinical theme with the release of two articles, which demonstrate ...

Research

JoVE Journal

Biology

Vidéo: February 2012: This Month in JoVE

August 2012: This Month in JoVE

Traditional microscopy requires lens objectives to magnify specimens, and can involve numerous optical components like additional objectives, filters, and mirrors to refract and direct light to optical sensors. The August 2012 issue of JoVE (Journal of Visualized Experiments) is marked by the third publication from the Ozcan Lab (University of California, Los Angeles) on their lens free lens-free "on-chip" microscopy platform, which they have pioneered.
Back in 2009, the Ozcan lab published their first article, which demonstrated the use of a lens-free imaging platform that could image cells within whole blood. This imaging technique involves placing a sample directly on an optoelectric sensor array, like the CCD or CMOS chips found in the standard camcorder. Then, LED illumination from above the sample casts shadows on the chip, which are recorded as digital holograms that can be subjected to image processing. Not only does this lensless imaging system allow for an extremely large field of view (FOV of 0.6-8 cm2), the lack of bulky optical components makes it excellent for microfluidic applications. The Ozcan group demonstrates this in their follow-up 2011 JoVE article, in which fluorescently labeled white blood cells are imaged within a microfluidic chip.
This August in JoVE, the Ozcan group demonstrates further advancements to their lens-free microscopy platform by applying it to tomographic imaging of the nematode, C. elegans. By changing the angle of illumination, using a motorized rotation stage, the Ozcan group shows how multiple holographic slices may be generated for a sample-which, following processing, can be combined into tomograms. The Ozcan group confirms that their 3D reconstruction of the worm is successful by citing that the pharyngeal tube, a 5-micron-thick structure, is only visible in a single slice and in a 3D reconstructed cross section.
The compact and inexpensive nature of the lens-free imaging systems - designed and assembled by the Ozcan group - make them well suited for point-of-care diagnostic applications, or even cell phone based microscopy that can be performed in the field.
At the Ernest Gallo Clinic and Research Center at University of California, San Francisco JoVE learns how to visualize morphological changes in single cells using three-dimensional fluorescence microscopy and computer analysis. In this procedure, cells are given agonist, antagonist plus agonist, or no treatment, and prepared for immunofluorescence microscopy. Three-dimensional images are acquired with the help of a two-photon laser system, and the fluorescence data are processed on the computer using Imaris and Matlab.
To demonstrate the power of this technique, our authors quantify single-cell phenotypic changes in transfected HEK293 cells. Three-dimensional morphometric analysis shows dramatic changes in cells treated with agonist. These changes are not always apparent when using conventional 2D analysis. This technique allows morphological changes in single cells to be quantified and characterized in response to pharmacologic stimuli, offering a powerful new assessment tool to the arsenal of drug discovery research.
This month, in JoVE Applied Physics, we travel to South Carolina to visit the School of Materials Science and Engineering at Clemson University. Here, researchers show us how to construct lithium batteries for laboratory research.
The basic components of a lithium coin cell are the working electrode, the lithium electrolyte, and a lithium foil counter electrode. The different components of the coin cell are carefully assembled and sealed with a crimping machine. The finished coin cell can then be characterized in a battery tester. Using their homemade coin cells, our researchers can experiment with using different materials to make the cathodes of lithium coin cells.
This month in JoVE Immunology and Infection, we head to Basel, Switzerland to witness two techniques for diagnosing helminth infections. We also see how investigators perform the shuttle run test in children, in order to assess the effects of these infections on physical fitness.
Helminths are parasitic worms that can live inside humans and animals. Many species infect the intestinal tract, and may be transmitted through soil. Our authors demonstrate the Kato-Katz technique, which is used for diagnosing several common soil-transmitted helminths. They also demonstrate the Baermann technique, which uses light to stimulate the migration of certain types of phototactic helminths out of sample preparations. The various types of helminth species can subsequently be determined based on morphology.
Our authors then demonstrate how to set up and perform a 20-meter shuttle run test for children, and to measure the impact of helminth infections on physical fitness. This method can help determine the true burden of soil-transmitted helminth infections on overall health.
This brief summary highlights but a few notable video-articles that will be released in August. We'll also feature articles that demonstrate how to express genes in the midbrain of the chick embryo, study neutrophil transmigration in parallel flow chambers lined with endothelial cells, and precisely measure proteolytic degradation of the extracellular matrix.

Traditional microscopy requires lens objectives to magnify specimens, and can involve numerous optical components like additional objectives, filters, and mirrors to refract and direct light to optical sensors. The August 2012 issue of JoVE (Journal of Visualized Experiments) is marked by the third publication from the Ozcan Lab (University of California, Los Angeles) on their lens-free "on-chip" microscopy platform, which they have pioneered.

Août 2012: Ce mois-ci dans JoVE

Traditional microscopy requires lens objectives to magnify specimens, and can involve numerous optical components like additional objectives, filters, and ...

Recherche

Biologie

2012: A Year In Review

Here's a look at some of the milestones and highlights of the year 2012 in Journal of Visualized Experiments (JoVE).
At the start of 2012, JoVE reached a major milestone by publishing our 1500th article. In this publication, in JoVE Bioengineering, Yu et al. described a method for analyzing the free radical composition of cigarette smoke. This method simulated cigarette puffing with a single-port smoking device, and combined it with electron spin resonance (ESR) spectroscopy to measure the degree to which antioxidant compounds can scavenge free radicals in cigarette smoke. A possible outcome of this research is the creation of less harmful cigarettes.
JoVE Bioengineering also contained the most-viewed article of 2012. Owczarczak et al. described a method for hacking a standard inkjet printer, loading ink cartridges with a cell-suspension "bioink," and printing lines of live cells onto glass slides. The thermal inkjet printing process creates temporary pores in the cell membrane, visualized by the incorporation of fluorescently labeled actin monomers. This concept, called "bioprinting," has many potential applications in cell and tissue engineering.
Also in 2012, JoVE Bioengineering featured a protocol by Hsia et al. for isolating and purifying spider silk protein, spinning it into fibers, and assessing the fiber strength. This protocol for laboratory-scale production of spider silk, which is stronger than tensile steel, can potentially be extended to large-scale manufacturing.
In JoVE Clinical and Translational Medicine, we featured a number of articles related to stroke, one of which. In one article, M&ouml;bius-Winkler et al. demonstrated placement of the WATCHMAN left atrial appendage occlusion device from Boston Scientific. This device is designed to prevent strokes by trapping clots within the left atrial appendage of the heart before they exit. Our authors demonstrated how to insert the guide wire through the femoral artery into the heart, advance the device into the left atrium, and deploy the device in the left atrial appendage.
Another article focused on stroke, Hamel et al. described the use of a driving simulator to study how patients compensate for visual field defects following stroke. By analyzing the compensatory gaze behavior of patients as they navigated through virtual driving courses with varying degrees of complexity, our authors see great potential for the use of driving simulators in stroke rehabilitation.
In JoVE Immunology and Infection, we published an article by Keyel et al. describing the real-time kinetics of immune cell responses to bacterial toxins using live cell microscopy. Combined with high-speed 3D confocal microscopy, this technique can also visualize the cellular repair response.
Also in JoVE Immunology and Infection, we featured an article by Yap et al. describing methods for diagnosing helminth infections in children. Helminths are parasitic worms that can infect the intestinal tract of humans and animals, and may be distinguished based on their morphology. The same article demonstrated how to measure the impact of helminth infections on physical fitness in children, which is a measure of overall health.
In JoVE Neuroscience, we featured a method by Hoffmann et al., who used tiny headphones to alter the auditory feedback in songbirds, and analyzed the computational and neurophysiological basis of vocal learning in birds when they adjust their singing in response to altered acoustic signals.
Also in JoVE Neuroscience, we moved from birds to bees with a method that assesses associative and non-associative tactile learning in honeybees. This method, by Mujagi&#263; et al., allowed bees to scan different metal surfaces with their antennae, then conditioned them to expect sugar water when their antennae touched particular surfaces, and analyzed the corresponding changes in antennal movement.
In 2012, we launched a brand-new section: JoVE Applied Physics, which features articles on subjects ranging from plasma physics to material science. The Applied Physics section also contained JoVE's 2000th video article, filmed in a synchrotron radiation facility, where Borisenko et al. showed how to determine the electronic structure of complex materials using angle-resolved photoemission spectroscopy.
In the JoVE General section, we published an article by Artioli et al. demonstrating the use of a portable gas analyzer to measure oxygen consumption during complex exercise - such as judo. By analyzing oxygen consumption and collecting blood for measuring plasma lactate concentration, this method can determine the relative contributions of different energy systems to specific aspects of complex exercise.
Finally, JoVE followed Dolhi et al. to a permanently ice-covered saline lake in Antarctica. There, scientists drilled through the ice to study single-celled microorganisms called protists that live in the harsh conditions of Antarctica.
This Year in Review was just a brief glimpse of a few of over 600 video articles that JoVE offered in 2012. Browse the JoVE archives to see thousands of other videos, and stay tuned for what's coming up this year in JoVE: The Journal of Visualized Experiments.

Here's a look at some of the milestones and highlights of the year 2012 in Journal of Visualized Experiments (JoVE).

2012: Une année en revue

 
 
Here's a look at some of the milestones and highlights of the year 2012 in Journal of Visualized Experiments (JoVE).
At the start of 2012, JoVE ...