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Two photon microscopy

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https://www.readbyqxmd.com/read/28443093/a-novel-cervical-spinal-cord-window-preparation-allows-for-two-photon-imaging-of-t-cell-interactions-with-the-cervical-spinal-cord-microvasculature-during-experimental-autoimmune-encephalomyelitis
#1
Neda Haghayegh Jahromi, Heidi Tardent, Gaby Enzmann, Urban Deutsch, Naoto Kawakami, Stefan Bittner, Dietmar Vestweber, Frauke Zipp, Jens V Stein, Britta Engelhardt
T-cell migration across the blood-brain barrier (BBB) is a crucial step in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Two-photon intravital microscopy (2P-IVM) has been established as a powerful tool to study cell-cell interactions in inflammatory EAE lesions in living animals. In EAE, central nervous system inflammation is strongly pronounced in the spinal cord, an organ in which 2P-IVM imaging is technically very challenging and has been limited to the lumbar spinal cord...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28442788/changes-in-structural-and-pigmentary-colours-in-response-to-cold-stress-in-polyommatus-icarus-butterflies
#2
Krisztián Kertész, Gábor Piszter, Zsolt Endre Horváth, Zsolt Bálint, László Péter Biró
While numerous papers have investigated the effects of thermal stress on the pigmentary colours of butterfly wings, such studies regarding structural colours are mostly lacking, despite the important role they play in sexual communication. To gain insight into the possible differences between the responses of the two kinds of colouration, we investigated the effects of prolonged cold stress (cooling at 5 °C for up to 62 days) on the pupae of Polyommatus icarus butterflies. The wing surfaces coloured by photonic crystal-type nanoarchitectures (dorsal) and by pigments (ventral) showed markedly different behaviours...
April 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28438833/g-protein-gi1-exhibits-basal-coupling-but-not-preassembly-with-g-protein-coupled-receptors
#3
Alexey Bondar, Josef Lazar
The Gi/o protein family transduces signals from a diverse group of G protein-coupled receptors (GPCRs). The observed specificity of Gi/o-GPCR coupling and high rate of Gi/o signal transduction have been hypothesized to be enabled by existence of stable associates between Gi/o proteins and their cognate GPCRs in the inactive state (Gi/o-GPCR preassembly). To test this hypothesis, we applied the recently developed technique of two-photon polarization microscopy (2PPM) to Gαi1 subunits labeled with fluorescent proteins and four GPCRs (the α2A-adrenergic receptor (α2A-AR), γ-aminobutyric acid receptor B (GABAB), cannabinoid receptor type 1 (CB1R) and dopamine receptor type 2 (D2R))...
April 24, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28437905/amplitude-modulation-of-femtosecond-laser-pulses-in-the-megahertz-range-for-frequency-multiplexed-two-photon-imaging
#4
Dmitri Tsyboulski, Natalia Orlova, Peter Saggau
We present a frequency-multiplexed multi-site two-photon imaging method utilizing amplitude modulation of femtosecond laser pulses in the MHz range to tag each excitation beam and the corresponding fluorescence signals with specific frequencies. The frequency tags are generated with an interferometric scheme employing acousto-optic deflectors (AODs) to achieve precise spatial overlap of femtosecond laser pulses with periodically varying phase shift. Creating matching excitation beam patterns in each interferometer arm using multiple AOD driving frequencies, and subsequently overlapping these matching patterns, results in multiple encoded excitation beams with unique beat frequencies available for scanning...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437194/comparison-of-three-final-irrigation-activation-techniques-effects-on-canal-cleanness-smear-layer-removal-and-dentinal-tubule-penetration-of-two-root-canal-sealers
#5
Elmas Turkel, Emel Olga Onay, Mete Ungor
OBJECTIVE: The aim of this study was to compare three final irrigation activation techniques with respect to their effects on debridement efficacy, smear layer removal, and dentinal tubule penetration of two different root canal sealers. BACKGROUND DATA: Different applications to improve the delivery of irrigating solutions within the root canal system are currently being investigated, as not all of the mechanisms and effects of these techniques have been clearly identified...
February 22, 2017: Photomedicine and Laser Surgery
https://www.readbyqxmd.com/read/28437133/the-impact-of-the-centrifuge-characteristics-and-centrifugation-protocols-on-the-cells-growth-factors-and-fibrin-architecture-of-a-leukocyte-and-platelet-rich-fibrin-l-prf-clot-and-membrane
#6
David M Dohan Ehrenfest, Nelson R Pinto, Andrea Pereda, Paula Jiménez, Marco Del Corso, Byung-Soo Kang, Mauricio Nally, Nicole Lanata, Hom-Lay Wang, Marc Quirynen
L-PRF (leukocyte- and platelet-rich fibrin) is one of the four families of platelet concentrates for surgical use and is widely used in oral and maxillofacial regenerative therapies. The first objective of this article was to evaluate the mechanical vibrations appearing during centrifugation in four models of commercially available table-top centrifuges used to produce L-PRF and the impact of the centrifuge characteristics on the cell and fibrin architecture of a L-PRF clot and membrane. The second objective of this article was to evaluate how changing some parameters of the L-PRF protocol may influence its biological signature, independently from the characteristics of the centrifuge...
April 24, 2017: Platelets
https://www.readbyqxmd.com/read/28436294/overexpression-of-vla-4-in-glial-restricted-precursors-enhances-their-endothelial-docking-and-induces-diapedesis-in-a-mouse-stroke-model
#7
Anna Jablonska, Daniel J Shea, Suyi Cao, Jeff Wm Bulte, Miroslaw Janowski, Konstantinos Konstantopoulos, Piotr Walczak
The loss of oligodendrocytes after stroke is one of the major causes of secondary injury. Glial-restricted progenitors (GRPs) have remylenating potential after intraparenchymal cerebral transplantation. The intraarterial (IA) injection route is an attractive gateway for global brain delivery, but, after IA infusion, naive GRPs fail to bind to the cerebral vasculature. The aim of this study was to test whether overexpression of Very Late Antigen-4 (VLA-4) increases endothelial docking and cerebral homing of GRPs in a stroke model...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28434998/use-of-two-photon-microscopy-to-study-leishmania-major-infection-of-the-skin
#8
REVIEW
Matheus Batista Carneiro, Leah Shan Hohman, Jackson G Egen, Nathan C Peters
Intra-vital two-photon microscopy (2P-IVM) allows for in-situ investigation of tissue organization, cell behavior and the dynamic interactions between different cell types in their natural environment. This methodology has also expanded our understanding of the immune response against pathogens. Leishmania are protozoan intracellular parasites that have adapted to successfully establish infection within the context of an inflammatory response in the skin following transmission by the bite of an infected sand fly...
April 18, 2017: Methods: a Companion to Methods in Enzymology
https://www.readbyqxmd.com/read/28420873/viewing-immune-regulation-as-it-happens-in-vivo-imaging-for-investigation-of-regulatory-t-cell-function
#9
REVIEW
Michael J Hickey, Zachary Chow
Regulatory T cells (Tregs) play indispensable roles in the immune system, in limiting excessive or inappropriate immune and inflammatory responses. They achieve this function via effects on other immune cells in the secondary lymphoid system, and in peripheral locations such as skin, gut and bone marrow. As for the more extensively-studied cellular players in the immune system, particularly dendritic cells and conventional T cells, in vivo imaging of Tregs via two-photon or multiphoton microscopy (MPM) has been central to the development of understanding how these cells function...
April 19, 2017: Immunology and Cell Biology
https://www.readbyqxmd.com/read/28419303/tumor-microtubes-convey-resistance-to-surgical-lesions-and-chemotherapy-in-gliomas
#10
Sophie Weil, Matthias Osswald, Gergely Solecki, Julia Grosch, Erik Jung, Dieter Lemke, Miriam Ratliff, Daniel Hänggi, Wolfgang Wick, Frank Winkler
Background: Primary and adaptive resistance against chemo- and radiotherapy, and local recurrence after surgery limit the benefits from these standard treatments in glioma patients. Recently we found that glioma cells can extend ultra-long membrane protrusions, "tumor microtubes" (TMs), for brain invasion, proliferation, and interconnection of single cells to a syncytium that is resistant to radiotherapy. We wondered whether TMs also convey resistance to the other two standard treatment modalities...
April 17, 2017: Neuro-oncology
https://www.readbyqxmd.com/read/28410977/intravital-imaging-of-the-kidney
#11
REVIEW
Takashi Hato, Seth Winfree, Pierre C Dagher
Two-photon intravital microscopy is a powerful tool that allows the examination of dynamic cellular processes in the live animal with unprecedented resolution. Indeed, it offers the ability to address unique biological questions that may not be solved by other means. While two-photon intravital microscopy has been successfully applied to study many organs, the kidney presents its own unique challenges that need to be overcome in order to optimize and validate imaging data. For kidney imaging, the complexity of renal architecture and salient autofluorescence merit special considerations as these elements directly impact image acquisition and data interpretation...
April 11, 2017: Methods: a Companion to Methods in Enzymology
https://www.readbyqxmd.com/read/28405638/a-two-photon-fluorescent-probe-for-specific-detection-of-hydrogen-sulfide-based-on-a-familiar-esipt-fluorophore-bearing-aie-characteristics
#12
Liyan Chen, Di Wu, Chang Su Lim, Dayoung Kim, Sang-Jip Nam, Woolin Lee, Gyungmi Kim, Hwan Myung Kim, Juyoung Yoon
Hydrogen sulfide (H2S) is a signaling gasotransmitter, which plays various roles in modulating the functions of different systems. In this study, a "turn-on" fluorescent probe for H2S was developed. The probe, whose design is based on a familiar excited state intramolecular proton transfer (ESIPT) fluorophore bearing aggregation-induced emission (AIE) characteristics, was found to exhibit an 80-fold fluorescence enhancement along with a large Stokes shift upon the addition of H2S. Furthermore, the probe was successfully utilized to detect H2S in HeLa cells with both one-photon and two-photon microscopy...
April 13, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28401931/early-neurovascular-dysfunction-in-a-transgenic-rat-model-of-alzheimer-s-disease
#13
Illsung L Joo, Aaron Y Lai, Paolo Bazzigaluppi, Margaret M Koletar, Adrienne Dorr, Mary E Brown, Lynsie A M Thomason, John G Sled, JoAnne McLaurin, Bojana Stefanovic
Alzheimer's disease (AD), pathologically characterized by amyloid-β peptide (Aβ) accumulation, neurofibrillary tangle formation, and neurodegeneration, is thought to involve early-onset neurovascular abnormalities. Hitherto studies on AD-associated neurovascular injury have used animal models that exhibit only a subset of AD-like pathologies and demonstrated some Aβ-dependent vascular dysfunction and destabilization of neuronal network. The present work focuses on the early stage of disease progression and uses TgF344-AD rats that recapitulate a broader repertoire of AD-like pathologies to investigate the cerebrovascular and neuronal network functioning using in situ two-photon fluorescence microscopy and laminar array recordings of local field potentials, followed by pathological analyses of vascular wall morphology, tau hyperphosphorylation, and amyloid plaques...
April 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28399361/photoexcited-state-confinement-in-two-dimensional-crystalline-anthracene-monolayer-at-room-temperature
#14
Masahiro Shibuta, Naoyuki Hirata, Toyoaki Eguchi, Atsushi Nakajima
Organic thin film electronics place a high demand on bottom-up technology to form a two-dimensionally (2D) functional unit consisting of a single molecular crystalline layer bound to a layered structure. As the strong interaction between a substrate and molecules makes it difficult to evaluate the electronic properties of organic films, the nature of electronic excited states has not been elucidated. Here, we study a 2D crystalline anthracene monolayer electronically decoupled by alkanethiolates on a gold substrate using scanning tunneling microscopy and time-resolved two-photon photoemission spectroscopy and unravel the geometric/electronic structures and excited electron dynamics...
April 25, 2017: ACS Nano
https://www.readbyqxmd.com/read/28388029/enhanced-photocurrent-of-transparent-cufeo2-photocathodes-by-self-light-harvesting-architecture
#15
Yunjung Oh, Wooseok Yang, Jimin Kim, Sunho Jeong, Jooho Moon
Efficient sunlight-driven water-splitting devices can be achieved by using an optically and energetically well-matched pair of photoelectrodes in a tandem configuration. The key for maximizing the photoelectrochemical efficiency is the use of a highly transparent front photoelectrode with a band gap below 2.0 eV. Herein, we propose two-dimensional (2D) photonic crystal (PC) structures consisting of a CuFeO2-decorated microsphere monolayer, which serve as self-light-harvesting architectures allowing for amplified light absorption and high transparency...
April 13, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28386573/spatial-landscape-of-oxygen-in-and-around-microvasculature-during-epileptic-events
#16
Cong Zhang, Mohammad Moeini, Frédéric Lesage
Measuring changes in cerebral oxygen in tissue microdomains during epilepsy is important to identify hypoxic potential. Here, using a custom-built two-photon microscopy system, we present microscopic measurements of oxygen partial pressure ([Formula: see text]) in cortical microvessels and tissue of anesthetized mice during 4-aminopyridine (4-AP)-induced epileptic seizures. Investigating epileptic events, we characterized the distribution of the "initial dip" in [Formula: see text] in arterioles, venules, and tissue near the 4-AP injection site...
January 2017: Neurophotonics
https://www.readbyqxmd.com/read/28386104/intubation-free-in-vivo-imaging-of-the-tracheal-mucosa-using-two-photon-microscopy
#17
Tibor Z Veres, Tamás Kopcsányi, Marko Tirri, Armin Braun, Masayuki Miyasaka, Ronald N Germain, Sirpa Jalkanen, Marko Salmi
The mucosal layer of conducting airways is the primary tissue exposed to inhaled microorganisms, allergens and pollutants. We developed an in vivo two-photon microscopic approach that allows performing dynamic imaging studies in the mouse trachea, which is a commonly used in vivo model of human small-diameter bronchi. By providing stabilized access to the tracheal mucosa without intubation, our setup uniquely allows dynamic in vivo imaging of mucociliary clearance and steady-state immune cell behavior within the complex airway mucosal tissue...
April 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28386058/cartilage-tissue-engineering-by-the-3d-bioprinting-of-ips-cells-in-a-nanocellulose-alginate-bioink
#18
Duong Nguyen, Daniel A Hägg, Alma Forsman, Josefine Ekholm, Puwapong Nimkingratana, Camilla Brantsing, Theodoros Kalogeropoulos, Samantha Zaunz, Sebastian Concaro, Mats Brittberg, Anders Lindahl, Paul Gatenholm, Annika Enejder, Stina Simonsson
Cartilage lesions can progress into secondary osteoarthritis and cause severe clinical problems in numerous patients. As a prospective treatment of such lesions, human-derived induced pluripotent stem cells (iPSCs) were shown to be 3D bioprinted into cartilage mimics using a nanofibrillated cellulose (NFC) composite bioink when co-printed with irradiated human chondrocytes. Two bioinks were investigated: NFC with alginate (NFC/A) or hyaluronic acid (NFC/HA). Low proliferation and phenotypic changes away from pluripotency were seen in the case of NFC/HA...
April 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28368994/revisiting-the-cornea-and-trabecular-meshwork-junction-with-2-photon-excitation-fluorescence-microscopy
#19
Catherine M Marando, Choul Yong, Jason A Liao, Jimmy K Lee, Roy S Chuck
PURPOSE: To investigate the collagen and elastin architecture at the junction of the human cornea and trabecular meshwork (TM). METHODS: The cornea, TM, and ciliary body (CB) tendons of unfixed human corneal buttons were imaged with an inverted 2-photon excited fluorescence microscope (FluoView FV-1000; Olympus, Central Valley, PA). The laser (Ti:sapphire) was tuned to 850 nm for 2-photon excitation. Backscatter signals of second harmonic generation and autofluorescence were collected through a 425/30-nm emission filter and a 525/45-nm emission filter, respectively...
March 31, 2017: Cornea
https://www.readbyqxmd.com/read/28364682/super-resolved-3-d-imaging-of-live-cells-organelles-from-bright-field-photon-transmission-micrographs
#20
Renata Rychtáriková, Tomáš Náhlík, Kevin Shi, Daria Malakhova, Petr Macháček, Rebecca Smaha, Jan Urban, Dalibor Štys
Current biological and medical research is aimed at obtaining a detailed spatiotemporal map of a live cell's interior to describe and predict cell's physiological state. We present here an algorithm for complete 3-D modelling of cellular structures from a z-stack of images obtained using label-free wide-field bright-field light-transmitted microscopy. The method visualizes 3-D objects with a volume equivalent to the area of a camera pixel multiplied by the z-height. The computation is based on finding pixels of unchanged intensities between two consecutive images of an object spread function...
March 18, 2017: Ultramicroscopy
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