The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Robia G Pautler - One of the best experts on this subject based on the ideXlab platform.
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in vivo trans synaptic tract tracing utilizing Manganese enhanced magnetic resonance imaging memri
NMR in Biomedicine, 2004Co-Authors: Robia G PautlerAbstract:It is well established that Manganese Ion (Mn2+) can access neurons through voltage-gated calcium (Ca2+) channels. Based upon this fundamental principle, Mn2+ has long been used in biomedical research as an indicator of Ca2+ influx in conjunctIon with fluorescent microscopy. AdditIonally, after entry into neurons, Mn2+ is transported down axons via microtubule based fast axonal transport. Furthermore, Mn2+ is paramagnetic, resulting in a shortening of the spin-lattice relaxatIon time-constant, T1, which yields positive contrast enhancement in T1-weighted MRI images, specific to tissues where the Ion has accumulated. Manganese-enhanced MRI (MEMRI) utilizes a combinatIon of these properties of Mn2+ to trace neuronal pathways in an MRI-detectable manner. The focus of this review will detail some of the current MEMRI tract-tracing methodologies in mice and non-human primates as well as biological applicatIons of MEMRI tract-tracing.
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in vivo neuronal tract tracing using Manganese enhanced magnetic resonance imaging
Magnetic Resonance in Medicine, 1998Co-Authors: Robia G Pautler, Afonso C Silva, Alan KoretskyAbstract:Development of efficient imaging techniques to trace neuro nal connectIons would be very useful. Manganese Ion (Mn2+) is an excellent T1 contrast agent for magnetic resonance imaging (MRI). Four reports utilizing radioactive Mn2+ in fish and rat brain indicate that Mn2+ may be useful for tracing neuronal connectIons. Therefore, the purpose of this work was to determine if Mn2+ can be used as an in vivo MRI neuronal tract tracer. The results indicate that topical admin istratIon of MnCI2 solutIon to the naris of mice as well as to the retinal ganglIon cells via intravitreal injectIon leads to en hancement of contrast along the respective pathways. There fore, applicatIon of Mn2+ to neurons allows the use of MRI to visualize neuronal connectIons.
Richard A. Collins - One of the best experts on this subject based on the ideXlab platform.
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IdentificatIon of phosphate groups involved in metal binding and tertiary interactIons in the core of the Neurospora VS ribozyme.
Journal of molecular biology, 1998Co-Authors: Vanita D. Sood, Tara L. Beattie, Richard A. CollinsAbstract:We have used ethylatIon protectIon experiments and modificatIon interference using phosphorothioate nucleosides to identify phosphate groups involved in the magnesium-dependent tertiary structure and functIon of the VS ribozyme, a small, self-cleaving RNA. Phosphorothioate interference-rescue experiments in the presence of the thiophilic Manganese Ion implicate four phosphate groups in direct metal Ion binding. Phosphorothioate substitutIon also creates a new Manganese binding site that increases the cis cleavage rate of the ribozyme, possibly by disrupting an inhibitory structure. Interpreting these data in the context of a recently developed structural model shows that almost all of the important phosphate groups are located in the central core of the ribozyme. The model suggests roles for certain phosphate groups in particular steps of RNA folding and identifies a candidate regIon for the active site of the ribozyme.
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Regular articleIdentificatIon of phosphate groups involved in metal binding and tertiary interactIons in the core of theNeurospora VS ribozyme1
Journal of molecular biology, 1998Co-Authors: Vanita D. Sood, Tara L. Beattie, Richard A. CollinsAbstract:We have used ethylatIon protectIon experiments and modificatIon interference using phosphorothioate nucleosides to identify phosphate groups involved in the magnesium-dependent tertiary structure and functIon of the VS ribozyme, a small, self-cleaving RNA. Phosphorothioate interference-rescue experiments in the presence of the thiophilic Manganese Ion implicate four phosphate groups in direct metal Ion binding. Phosphorothioate substitutIon also creates a new Manganese binding site that increases the cis cleavage rate of the ribozyme, possibly by disrupting an inhibitory structure. Interpreting these data in the context of a recently developed structural model shows that almost all of the important phosphate groups are located in the central core of the ribozyme. The model suggests roles for certain phosphate groups in particular steps of RNA folding and identifies a candidate regIon for the active site of the ribozyme.
Alan Koretsky - One of the best experts on this subject based on the ideXlab platform.
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in vivo neuronal tract tracing using Manganese enhanced magnetic resonance imaging
Magnetic Resonance in Medicine, 1998Co-Authors: Robia G Pautler, Afonso C Silva, Alan KoretskyAbstract:Development of efficient imaging techniques to trace neuro nal connectIons would be very useful. Manganese Ion (Mn2+) is an excellent T1 contrast agent for magnetic resonance imaging (MRI). Four reports utilizing radioactive Mn2+ in fish and rat brain indicate that Mn2+ may be useful for tracing neuronal connectIons. Therefore, the purpose of this work was to determine if Mn2+ can be used as an in vivo MRI neuronal tract tracer. The results indicate that topical admin istratIon of MnCI2 solutIon to the naris of mice as well as to the retinal ganglIon cells via intravitreal injectIon leads to en hancement of contrast along the respective pathways. There fore, applicatIon of Mn2+ to neurons allows the use of MRI to visualize neuronal connectIons.
Guy Campet - One of the best experts on this subject based on the ideXlab platform.
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Effect of chromium substitutIon on the lattice vibratIon of spinel lithium manganate: A new interpretatIon of the Raman spectrum of LiMn2O4
Journal of Physical Chemistry B, 2004Co-Authors: Seong-ju Hwang, Jin-ho Choy, Seung-han Park, Guy CampetAbstract:The variatIon of the lattice vibratIon of spinel lithium manganate upon chromium substitutIon has been investigated by performing a combinative micro-Raman and X-ray absorptIon spectroscopic (XAS) analysis. As the Manganese Ion in the spinel LiMn2-xCrxO4 is replaced by a chromium Ion, the relative intensities of two main Raman peaks at ~580 and ~620 cm-1 are remarkably changed. This change cannot be understood by the previous peak assignment on the basis of the average crystal structure of the cubic spinel lattice...
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evolutIon of local structure around Manganese in layered limno2 upon chemical and electrochemical delithiatIon relithiatIon
Chemistry of Materials, 2000Co-Authors: Seong-ju Hwang, And Hyo-suk Park, Jin-ho Choy, Guy CampetAbstract:Mn K-edge X-ray absorptIon spectroscopic (XAS) analyses have been performed to probe the evolutIon of electronic and crystal structures of layered LiMnO2 upon chemical and electrochemical delithiatIon/relithiatIon. According to the X-ray absorptIon near-edge structure studies, it becomes clear that the trivalent Manganese Ion in LiMnO2 is significantly oxidized by acid treatment and is not fully recovered by subsequent lithiatIon reactIon with n-BuLi. The extended X-ray absorptIon fine structure results presented here demonstrate that the local structure around Manganese in LiMnO2 is changed from a layered α-NaFeO2-type structure to a spinel-like one upon chemical delithiatIon reactIon. It is also found from the XAS analyses for the cycled LiMnO2 that the electrochemical charge−discharge process gives rise not only to the partial oxidatIon of Manganese Ion but also to the migratIon of Mn into the interlayer lithium site, resulting in the coexistence of the layered structure and the spinel one. Such result...
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EvolutIon of Local Structure around Manganese in Layered LiMnO2 upon Chemical and Electrochemical DelithiatIon/RelithiatIon
Chemistry of Materials, 2000Co-Authors: Seong-ju Hwang, And Hyo-suk Park, Jin-ho Choy, Guy CampetAbstract:Mn K-edge X-ray absorptIon spectroscopic (XAS) analyses have been performed to probe the evolutIon of electronic and crystal structures of layered LiMnO2 upon chemical and electrochemical delithiatIon/relithiatIon. According to the X-ray absorptIon near-edge structure studies, it becomes clear that the trivalent Manganese Ion in LiMnO2 is significantly oxidized by acid treatment and is not fully recovered by subsequent lithiatIon reactIon with n-BuLi. The extended X-ray absorptIon fine structure results presented here demonstrate that the local structure around Manganese in LiMnO2 is changed from a layered α-NaFeO2-type structure to a spinel-like one upon chemical delithiatIon reactIon. It is also found from the XAS analyses for the cycled LiMnO2 that the electrochemical charge−discharge process gives rise not only to the partial oxidatIon of Manganese Ion but also to the migratIon of Mn into the interlayer lithium site, resulting in the coexistence of the layered structure and the spinel one. Such result...
Yongmin Chang - One of the best experts on this subject based on the ideXlab platform.
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Manganese enhanced auditory tract tracing mri with cochlear injectIon
Magnetic Resonance Imaging, 2007Co-Authors: Jaewon Lee, Jiae Park, Jaejun Lee, Sungjin Bae, Sangheun Lee, Jaechang Jung, Myoungnam Kim, Jongmin Lee, Seongku Woo, Yongmin ChangAbstract:Abstract Recent studies have demonstrated the use of Manganese Ion (Mn 2+ ) as an in vivo neuronal tract tracer. In contrast to histological approaches, Manganese tracing can be performed repeatedly on the same living animal. In this study, we describe the neuroaxonal tracing of the auditory pathway in the living guinea pig, relying on the fact that Mn 2+ Ion enters excitable cells through voltage-gated calcium channels and is an excellent MRI paramagnetic tract-tracing agent. Small focal injectIons of Mn 2+ Ion into the cochlea produced significant contrast enhancement along the known neuronal circuitry. This in vivo approach, allowing repeated measures, is expected to open new vistas to study auditory physiology and to provide new insights on in vivo axonal transport and neuronal activity in the central auditory system.