The Experts below are selected from a list of 45 Experts worldwide ranked by ideXlab platform
Yi Chen - One of the best experts on this subject based on the ideXlab platform.
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continuous on line monitoring of extracellular ascorbate depletion in the rat striatum induced by global ischemia with carbon nanotube modified glassy carbon electrode integrated into a thin layer radial flow cell
Analytical Chemistry, 2005Co-Authors: Meining Zhang, Kuanping Gong, Lei Su, Yi ChenAbstract:This study describes a novel analytical system integrating in vivo microdialysis sampling with a radial thin-layer flow cell with a single-walled carbon nanotube (SWNT)-modified glassy carbon electrode as working electrode for continuous and on-line monitoring of ascorbate depletion in the rat striatum induced by global ischemia. The SWNTs, especially those after vacuum heat treatment at 500 °C, are found to be able to enhance the electron-transfer kinetics of ascorbate oxidation at a low potential (ca. −50 mV) and possess a strong ability against electrode fouling. These properties essentially make it possible to determine ascorbate with a good stability and high selectivity against catecholamines and their metabolites and other electroactive species of physiological Levels. While being integrated with in vivo microdialysis to assemble an on-line analytical system, the electrode is proved useful for continuous and sensitive monitoring of the basal Dialysate Level of ascorbate and its depletion in the rat...
Alexander Baethmann - One of the best experts on this subject based on the ideXlab platform.
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Release of excitatory amino acids in the penumbra of a focal cortical necrosis.
Journal of Neurotrauma, 2002Co-Authors: M. Stoffel, J. Eriskat, Nikolaus Plesnila, Monika Fürst, Alexander BaethmannAbstract:A cortical tissue necrosis from focal trauma expands between 30% and 300% from its initial size within 24 h, depending on the species studied. To shed light on the pathophysiological processes in the penumbra 1 zone after a focal cortical lesion, the release of excitatory amino acids into the traumatic penumbra zone 1 was measured throughout the entire period of necrosis expansion. A microdialysis probe was inserted at an oblique angle into the cortex of Sprague-Dawley rats 2 mm below the brain surface. One day later, a highly standardized cortical freezing lesion was induced at the brain cortex above the microdialysis probe. Dialysate was continuously collected prior to, during, and up to 24 h after trauma and analyzed for primary amino acids. In each animal, it was confirmed histologically that the tip of the microdialysis probe was localized in the gray matter in close proximity to the primary lesion. Following induction of the trauma, a statistically significant sharp increase of the Dialysate Level of aspartate, glutamate, glycine, and serine was observed. Thereafter, the Dialysate Levels of these amino acids returned to baseline Levels without any further increase throughout the remaining observation period. This process ranged in time from a few minutes to a few hours. The Level of alanine in the Dialysate was essentially not altered throughout the experiment. Although the early post-traumatic increase of the excitatory neurotransmitters aspartate and glutamate may well contribute to the secondary lesion growth of a cortical necrosis after trauma, glutamate receptor targeted therapeutic intervention may be in view of these findings of limited use when initiated post trauma.
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The Penumbra Zone of a Traumatic Cortical Lesion: a Microdialysis Study of Excitatory Amino Acid Release
Acta Neurochirurgica, 1997Co-Authors: M. Stoffel, J. Eriskat, M. Plesnila, N. Aggarwal, Alexander BaethmannAbstract:A cortical tissue necrosis from focal trauma expands to 150% of its initial volume within 24 hrs. It is currently unknown, whether this phenomenon is part of the primary traumatic lesion or if it involves secondary mechanisms such as the release of excitatory amino acids into the traumatic penumbra zone. A microdialysis probe was inserted for that purpose in an oblique angle into the cortex of Sprague-Dawley rats, approximately 2 mm below the brain surface. One day later a highly standardized cortical freezing lesion was induced at the brain cortex above the microdialysis probe. Dialysate was collected prior to, during, and after trauma in 10 min intervals. In each animal, it was confirmed histologically, that the tip of the microdialysis probe was localized in the grey matter in close vicinity to the primary lesion. Following induction of the trauma a statistically significant increase of the Dialysate Level of aspartate, glutamate, glycine, and serine was observed, whereas that of alanine was not altered throughout the experiment. The posttraumatic increase of the excitatory neurotransmitters aspartate and glutamate indicates that these amino acids are involved in the secondary lesion growth after trauma. Confirmation of this hypothesis would require that specific antagonization of these excitotoxic amino acids is inhibiting growth of the lesion.
Mingya Li - One of the best experts on this subject based on the ideXlab platform.
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extracellular dopamine norepinephrine and serotonin in the ventral tegmental area and nucleus accumbens of freely moving rats during intracerebral dialysis following systemic administration of cocaine and other uptake blockers
Psychopharmacology, 1997Co-Authors: Maarten E A Reith, Mingya LiAbstract:Extracellular Levels of dopamine (DA), serotonin (5-HT), and norepinephrine (NE) were measured by microdialysis in conscious rats equipped with dual probes, one in the ventral tegmental area (VTA) and another one in the contralateral nucleus accumbens (NACC). Dialysate content of all amines in both regions was essentially abolished by local infusion of tetrodotoxin (1 μM) or Ca2+-free buffer. Injection of the selective DA uptake blocker GBR 12935 (15 mg/kg IP) increased DA, as well as NE and, to a lesser extent, 5-HT in the VTA; it increased DA more than 5-HT in the NACC. The selective NE uptake blocker desipramine (10 mg/kg IP) increased NE but also 5-HT in the VTA and NACC; the DA Level was persistently enhanced in the VTA, whereas in the NACC it initially rose and then fell below baseline value. The selective 5-HT uptake blocker citalopram (15 mg/kg IP) was generally more effective in elevating Dialysate Level of 5-HT than that of other amines in both regions. Cocaine (20 mg/kg IP) was non-selective in enhancing all three amines in both regions. There is considerable crosstalk between monoamine systems occurring upon systemic administration of uptake blockers, and the VTA and NACC are notably different in the time course of the DA effect (long-lasting versus transient).
Meining Zhang - One of the best experts on this subject based on the ideXlab platform.
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continuous on line monitoring of extracellular ascorbate depletion in the rat striatum induced by global ischemia with carbon nanotube modified glassy carbon electrode integrated into a thin layer radial flow cell
Analytical Chemistry, 2005Co-Authors: Meining Zhang, Kuanping Gong, Lei Su, Yi ChenAbstract:This study describes a novel analytical system integrating in vivo microdialysis sampling with a radial thin-layer flow cell with a single-walled carbon nanotube (SWNT)-modified glassy carbon electrode as working electrode for continuous and on-line monitoring of ascorbate depletion in the rat striatum induced by global ischemia. The SWNTs, especially those after vacuum heat treatment at 500 °C, are found to be able to enhance the electron-transfer kinetics of ascorbate oxidation at a low potential (ca. −50 mV) and possess a strong ability against electrode fouling. These properties essentially make it possible to determine ascorbate with a good stability and high selectivity against catecholamines and their metabolites and other electroactive species of physiological Levels. While being integrated with in vivo microdialysis to assemble an on-line analytical system, the electrode is proved useful for continuous and sensitive monitoring of the basal Dialysate Level of ascorbate and its depletion in the rat...
M. Stoffel - One of the best experts on this subject based on the ideXlab platform.
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Release of excitatory amino acids in the penumbra of a focal cortical necrosis.
Journal of Neurotrauma, 2002Co-Authors: M. Stoffel, J. Eriskat, Nikolaus Plesnila, Monika Fürst, Alexander BaethmannAbstract:A cortical tissue necrosis from focal trauma expands between 30% and 300% from its initial size within 24 h, depending on the species studied. To shed light on the pathophysiological processes in the penumbra 1 zone after a focal cortical lesion, the release of excitatory amino acids into the traumatic penumbra zone 1 was measured throughout the entire period of necrosis expansion. A microdialysis probe was inserted at an oblique angle into the cortex of Sprague-Dawley rats 2 mm below the brain surface. One day later, a highly standardized cortical freezing lesion was induced at the brain cortex above the microdialysis probe. Dialysate was continuously collected prior to, during, and up to 24 h after trauma and analyzed for primary amino acids. In each animal, it was confirmed histologically that the tip of the microdialysis probe was localized in the gray matter in close proximity to the primary lesion. Following induction of the trauma, a statistically significant sharp increase of the Dialysate Level of aspartate, glutamate, glycine, and serine was observed. Thereafter, the Dialysate Levels of these amino acids returned to baseline Levels without any further increase throughout the remaining observation period. This process ranged in time from a few minutes to a few hours. The Level of alanine in the Dialysate was essentially not altered throughout the experiment. Although the early post-traumatic increase of the excitatory neurotransmitters aspartate and glutamate may well contribute to the secondary lesion growth of a cortical necrosis after trauma, glutamate receptor targeted therapeutic intervention may be in view of these findings of limited use when initiated post trauma.
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The Penumbra Zone of a Traumatic Cortical Lesion: a Microdialysis Study of Excitatory Amino Acid Release
Acta Neurochirurgica, 1997Co-Authors: M. Stoffel, J. Eriskat, M. Plesnila, N. Aggarwal, Alexander BaethmannAbstract:A cortical tissue necrosis from focal trauma expands to 150% of its initial volume within 24 hrs. It is currently unknown, whether this phenomenon is part of the primary traumatic lesion or if it involves secondary mechanisms such as the release of excitatory amino acids into the traumatic penumbra zone. A microdialysis probe was inserted for that purpose in an oblique angle into the cortex of Sprague-Dawley rats, approximately 2 mm below the brain surface. One day later a highly standardized cortical freezing lesion was induced at the brain cortex above the microdialysis probe. Dialysate was collected prior to, during, and after trauma in 10 min intervals. In each animal, it was confirmed histologically, that the tip of the microdialysis probe was localized in the grey matter in close vicinity to the primary lesion. Following induction of the trauma a statistically significant increase of the Dialysate Level of aspartate, glutamate, glycine, and serine was observed, whereas that of alanine was not altered throughout the experiment. The posttraumatic increase of the excitatory neurotransmitters aspartate and glutamate indicates that these amino acids are involved in the secondary lesion growth after trauma. Confirmation of this hypothesis would require that specific antagonization of these excitotoxic amino acids is inhibiting growth of the lesion.