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Li Xie, Liqin Chen, Pan Gu, Lanlan Wei, Xuejun Kang
The extraction and analysis of catecholamine neurotransmitters in biological fluids is of great importance in assessing nervous system function and related diseases, but their precise measurement is still a challenge. Many protocols have been described for neurotransmitter measurement by a variety of instruments, including high-pressure liquid chromatography (HPLC). However, there are shortcomings, such as complicated operation or hard-to-detect multiple targets, which cannot be avoided, and presently, the dominant analysis technique is still HPLC coupled with sensitive electrochemical or fluorimetric detection, due to its high sensitivity and good selectivity...
March 1, 2018: Journal of Visualized Experiments: JoVE
Madeline Williams, Smrithi Prem, Xiaofeng Zhou, Paul Matteson, Percy Luk Yeung, Chi-Wei Lu, Zhiping Pang, Linda Brzustowicz, James H Millonig, Emanuel Dicicco-Bloom
Human brain development proceeds through a series of precisely orchestrated processes, with earlier stages distinguished by proliferation, migration, and neurite outgrowth; and later stages characterized by axon/dendrite outgrowth and synapse formation. In neurodevelopmental disorders, often one or more of these processes are disrupted, leading to abnormalities in brain formation and function. With the advent of human induced pluripotent stem cell (hiPSC) technology, researchers now have an abundant supply of human cells that can be differentiated into virtually any cell type, including neurons...
March 2, 2018: Journal of Visualized Experiments: JoVE
Diogo Castro Vaz, Edouard Lesne, Anke Sander, Hiroshi Naganuma, Eric Jacquet, Jacobo Santamaria, Agnès Barthélémy, Manuel Bibes
The quasi 2D electron system (q2DES) that forms at the interface between LaAlO3 (LAO) and SrTiO3 (STO) has attracted much attention from the oxide electronics community. One of its hallmark features is the existence of a critical LAO thickness of 4 unit-cells (uc) for interfacial conductivity to emerge. Although electrostatic mechanisms have been proposed in the past to describe the existence of this critical thickness, the importance of chemical defects has been recently accentuated. Here, we describe the growth of metal/LAO/STO heterostructures in an ultra-high vacuum (UHV) cluster system combining pulsed laser deposition (to grow the LAO), magnetron sputtering (to grow the metal) and X-ray photoelectron spectroscopy (XPS)...
February 8, 2018: Journal of Visualized Experiments: JoVE
Wyatt E Lanik, Lily Xu, Cliff J Luke, Elise Z Hu, Pranjal Agrawal, Victoria S Liu, Rajesh Kumar, Alexa M Bolock, Congrong Ma, Misty Good
Human small intestinal enteroids are derived from the crypts and when grown in a stem cell niche contain all of the epithelial cell types. The ability to establish human enteroid ex vivo culture systems are important to model intestinal pathophysiology and to study the particular cellular responses involved. In recent years, enteroids from mice and humans are being cultured, passaged, and banked away for future use in several laboratories across the world. This enteroid platform can be used to test the effects of various treatments and drugs and what effects are exerted on different cell types in the intestine...
February 15, 2018: Journal of Visualized Experiments: JoVE
Joseph B DeShields, Rachel A Bomberger, James W Woodhall, David L Wheeler, Natalia Moroz, Dennis A Johnson, Kiwamu Tanaka
On-site diagnosis of plant diseases can be a useful tool for growers for timely decisions enabling the earlier implementation of disease management strategies that reduce the impact of the disease. Presently in many diagnostic laboratories, the polymerase chain reaction (PCR), particularly real-time PCR, is considered the most sensitive and accurate method for plant pathogen detection. However, laboratory-based PCRs typically require expensive laboratory equipment and skilled personnel. In this study, soil-borne pathogens of potato are used to demonstrate the potential for on-site molecular detection...
February 23, 2018: Journal of Visualized Experiments: JoVE
Ryan J Mailloux, Adrian Young, Marisa O'Brien, Robert Morris Gill
It has been reported that mitochondria can contain up to 12 enzymatic sources of reactive oxygen species (ROS). A majority of these sites include flavin-dependent respiratory complexes and dehydrogenases that produce a mixture of superoxide (O2●- ) and hydrogen peroxide (H2O2). Accurate quantification of the ROS-producing potential of individual sites in isolated mitochondria can be challenging due to the presence of antioxidant defense systems and side reactions that also form O2●- /H2O2. Use of nonspecific inhibitors that can disrupt mitochondrial bioenergetics can also compromise measurements by altering ROS release from other sites of production...
February 24, 2018: Journal of Visualized Experiments: JoVE
Miki Dalmau-Pastor, Jordi Vega, Francesc Malagelada, Fernando Peña, Maria Cristina Manzanares-Céspedes
The growing popularity of minimally invasive surgical (MIS) procedures makes it necessary that new anatomical references arise, to aid in tridimensional orientation and localization of structures that are not directly visible to the surgeon. This is especially critical for structures at risk like nerves or blood vessels. Optimization of the handling of cadaveric material and the combination of multiple techniques compensate for the limited availability of adequate specimens. The described protocol combines anatomical plane-by-plane dissection and sectional anatomy of fresh-frozen specimens to help localize relevant structures, such as nerves, arteries, veins and to correctly position the portals during MIS procedures...
February 17, 2018: Journal of Visualized Experiments: JoVE
Hao-Hsiang Hsu, John-Kevin Kracht, Laura Elisabeth Harder, Kerstin Rudnik, Gerd Lindner, Katharina Schimek, Uwe Marx, Ralf Pörtner
In vitro cultivated skin models have become increasingly relevant for pharmaceutical and cosmetic applications, and are also used in drug development as well as substance testing. These models are mostly cultivated in membrane-insert systems, their permeability toward different substances being an essential factor. Typically, applied methods for determination of these parameters usually require large sample sizes (e.g., Franz diffusion cell) or laborious equipment (e.g., fluorescence recovery after photobleaching (FRAP))...
February 23, 2018: Journal of Visualized Experiments: JoVE
Shereen M Hamza, John E Hall
Renal sympathetic nerves contribute significantly to both physiological and pathophysiological phenomena. Evaluating renal sympathetic nerve activity (RSNA) is of great interest in many areas of research such as chronic kidney disease, hypertension, heart failure, diabetes and obesity. Unequivocal assessment of the role of the sympathetic nervous system is thus imperative for proper interpretation of experimental results and understanding of disease processes. RSNA has been traditionally measured in anesthetized rodents, including mice...
February 14, 2018: Journal of Visualized Experiments: JoVE
Andrew K Fuller, Benjamin D Bice, Ashlee R Venancio, Olivia M Crowley, Ambur M Staab, Stephanie J Georges, Julio R Hidalgo, Annika V Warncke, Melinda L Angus-Hill
Several recent studies have illustrated the beneficial effects of living in an enriched environment on improving human disease. In mice, environmental enrichment (EE) reduces tumorigenesis by activating the mouse immune system, or affects tumor bearing animal survival by stimulating the wound repair response, including improved microbiome diversity, in the tumor microenvironment. Provided here is a detailed procedure to assess the effects of environmental enrichment on the biodiversity of the microbiome in a mouse colon tumor model...
February 28, 2018: Journal of Visualized Experiments: JoVE
Zhijuan Qiu, Brian S Sheridan
The intestinal immune system plays an essential role in maintaining the barrier function of the gastrointestinal tract by generating tolerant responses to dietary antigens and commensal bacteria while mounting effective immune responses to enteropathogenic microbes. In addition, it has become clear that local intestinal immunity has a profound impact on distant and systemic immunity. Therefore, it is important to study how an intestinal immune response is induced and what the immunologic outcome of the response is...
February 28, 2018: Journal of Visualized Experiments: JoVE
José R Agudo, Jiwon Han, Jinyoung Park, Sinyoung Kwon, Soebiakto Loekman, Giovanni Luzi, Christoph Linderberger, Antonio Delgado, Andreas Wierschem
Two different experimental methods for determining the threshold of particle motion as a function of geometrical properties of the bed from laminar to turbulent flow conditions are presented. For that purpose, the incipient motion of a single bead is studied on regular substrates that consist of a monolayer of fixed spheres of uniform size that are regularly arranged in triangular and quadratic symmetries. The threshold is characterized by the critical Shields number. The criterion for the onset of motion is defined as the displacement from the original equilibrium position to the neighboring one...
February 22, 2018: Journal of Visualized Experiments: JoVE
Ji-Eun Kim, Kyung-Ok Cho
Temporal lobe epilepsy (TLE) is a common neurological disorder in adulthood. For translational studies of chronic epilepsy, pilocarpine-induced status epilepticus (SE) is frequently selected to recapitulate spontaneous recurrent seizures (SRS). Here we present a protocol of SE induction by intraperitoneal (i.p.) injection of pilocarpine and monitoring of chronic recurring seizures in live animals using a wireless telemetry video and electroencephalogram (EEG) system. We demonstrated notable behavioral changes that need attention after pilocarpine injection and their correlation with hippocampal neuronal loss at 7 days and 6 weeks post-pilocarpine...
February 27, 2018: Journal of Visualized Experiments: JoVE
Gizem Ertürk, Rolf Lood
The ability to detect and quantitate biomolecules in complex solutions has always been highly sought-after within natural science; being used for the detection of biomarkers, contaminants, and other molecules of interest. A commonly used technique for this purpose is the Enzyme-linked Immunosorbent Assay (ELISA), where often one antibody is directed towards a specific target molecule, and a second labeled antibody is used for the detection of the primary antibody, allowing for the absolute quantification of the biomolecule under study...
February 16, 2018: Journal of Visualized Experiments: JoVE
Takuma Iguchi, Noriyo Niino, Satoshi Tamai, Ken Sakurai, Kazuhiko Mori
RT-qPCR is one of the most common methods to assess individual target miRNAs. MiRNAs levels are generally measured relative to a reference sample. This approach is appropriate for examining physiological changes in target gene expression levels. However, absolute quantification using better statistical analysis is preferable for a comprehensive assessment of gene expression levels. Absolute quantification is still not in common use. This report describes a protocol for measuring the absolute levels of plasma miRNA, using RT-qPCR with or without pre-amplification...
February 12, 2018: Journal of Visualized Experiments: JoVE
Chao Tian, Wei Zhang, Van Phuc Nguyen, Xueding Wang, Yannis M Paulus
Photoacoustic ocular imaging is an emerging ophthalmic imaging technology that can noninvasively visualize ocular tissue by converting light energy into sound waves and is currently under intensive investigation. However, most reported work to date is focused on the imaging of the posterior segment of the eyes of small animals, such as rats and mice, which poses challenges for clinical human translation due to small eyeball sizes. This manuscript describes a novel photoacoustic microscopy (PAM) and optical coherence tomography (OCT) dual-modality system for posterior segment imaging of the eyes of larger animals, such as rabbits...
February 8, 2018: Journal of Visualized Experiments: JoVE
Joseph Ochaba, Eva L Morozko, Jacqueline G O'Rourke, Leslie M Thompson
The accumulation of misfolded proteins is central to pathology in Huntington's disease (HD) and many other neurodegenerative disorders. Specifically, a key pathological feature of HD is the aberrant accumulation of mutant HTT (mHTT) protein into high molecular weight complexes and intracellular inclusion bodies composed of fragments and other proteins. Conventional methods to measure and understand the contributions of various forms of mHTT-containing aggregates include fluorescence microscopy, western blot analysis, and filter trap assays...
February 27, 2018: Journal of Visualized Experiments: JoVE
Jessica C Stark, Euan Wallace, Rebecca Lim, Bryan Leaw
Microglia, the resident immune cells in the brain, are the first responders to inflammation or injury in the central nervous system. Recent research has revealed microglia to be dynamic, capable of assuming both pro-inflammatory and anti-inflammatory phenotypes. Both M1 (pro-inflammatory) and M2 (pro-reparative) phenotypes play an important role in neuroinflammatory conditions such as perinatal brain injury, and exhibit differing functions in response to certain environmental stimuli. The modulation of microglial activation has been noted to confer neuroprotection thus suggesting microglia may have therapeutic potential in brain injury...
February 16, 2018: Journal of Visualized Experiments: JoVE
Madeleine S Durkee, Landon D Nash, Fatemeh Nooshabadi, Jeffrey D Cirillo, Duncan J Maitland, Kristen C Maitland
The rapid development of new optical imaging techniques is dependent on the availability of low-cost, customizable, and easily reproducible standards. By replicating the imaging environment, costly animal experiments to validate a technique may be circumvented. Predicting and optimizing the performance of in vivo and ex vivo imaging techniques requires testing on samples that are optically similar to tissues of interest. Tissue-mimicking optical phantoms provide a standard for evaluation, characterization, or calibration of an optical system...
February 12, 2018: Journal of Visualized Experiments: JoVE
Chao Xiong, Zhiquan Zhang, Gurpreet S Baht, Niccolo Terrando
Surgery is commonly used to improve and maintain quality of life. Unfortunately, in vulnerable patients such as the elderly, complications may occur and significantly diminish the outcome. Indeed, after routine orthopedic surgery to repair a fracture, as many as 50% of elderly patients suffer from neurologic complications like delirium. Also, the capacity to heal and regenerate tissue after surgery decreases with age, and can impact the quality of fracture repair and even osseous integration of implants. Thus, a better understanding of mechanisms that drive these age-dependent changes could provide strategic targets to minimize risk for such complications and optimize outcomes...
February 27, 2018: Journal of Visualized Experiments: JoVE
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