The Experts below are selected from a list of 231 Experts worldwide ranked by ideXlab platform
Luigi Zecca - One of the best experts on this subject based on the ideXlab platform.
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Neuromelanin of the Human Substantia nigra: An Update
Neurotoxicity Research, 2014Co-Authors: Fabio A. Zucca, Emy Basso, Francesca A. Cupaioli, Emanuele Ferrari, David Sulzer, Luigi Casella, Luigi ZeccaAbstract:Dopaminergic neurons of the Substantia nigra selectively degenerate over the course of Parkinson’s disease. These neurons are also the most heavily pigmented cells of the brain, accumulating the dark pigment neuromelanin over a lifetime. The massive presence of neuromelanin in these brain areas has long been suspected as a key factor involved in the selective vulnerability of neurons. The high concentration of neuromelanin in Substantia nigra neurons seems to be linked to the presence of considerable amounts of cytosolic dopamine that have not been sequestered into synaptic vesicles. Over the past few years, studies have uncovered a dual nature of neuromelanin. Intraneuronal neuromelanin can be a protective factor, shielding the cells from toxic effects of redox active metals, toxins, and excess of cytosolic catecholamines. In contrast, neuromelanin released by dying neurons can contribute to the activation of neuroglia triggering the neuroinflammation that characterizes Parkinson’s disease. This article reviews recent studies on the molecular aspects of neuromelanin of the human Substantia nigra.
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Iron and Other Metals in Neuromelanin, Substantia nigra, and Putamen of Human Brain
Journal of Neurochemistry, 2008Co-Authors: Luigi Zecca, Roberto Di Pietra, Claudio Mecacci, Davide Radice, Enrico SabbioniAbstract:: Radiochemical neutron activation analysis has been used to determine the concentration of 36 elements in neuromelanin, 22 elements in Substantia nigra, and 32 elements in putamen of healthy subjects without signs of neurological disorders. Substantia nigra and putamen tissues were carefully dissected from the brain using special surgical instruments and tools as well as an adequate sampling procedure to avoid the risk of metal contamination during sampling. Neuromelanin was isolated from putamen by a multiple-step procedure (extraction with phosphate buffer, lipid and protein elimination by methanol extraction, and sodium dodecyl sulfate-proteinase). The isolated pigment as well as Substantia nigra and putamen underwent neutron activation analysis involving irradiation in a high-neutron-flux reactor, radiochemical separations, and counting of the induced radionuclides by computer-based gamma-ray spectrometry. Iron was the element present in the highest concentration in all analyzed samples. The amount of iron was similar in Substantia nigra and putamen (3,000 and 3,830 ng/mg wet weight, respectively) and 10 times higher in neuromelanin (30,800 ng/mg dry weight). Zinc was also present at high levels in three samples, ranging from 16.8 (Substantia nigra) to 1,500 ng/mg (neuromelanin). Elements such as Zn, Cr, Se, Sr, Co, Sb, Ni, Hg, Ce, Au, Ag, Ta, and Sc were present in neuromelanin at much higher concentrations than in Substantia nigra and putamen. These findings indicate that Substantia nigra and putamen contain metals at higher concentrations than observed in blood and that neuromelanin has a particular affinity for metals.
Adrienne C Lahti - One of the best experts on this subject based on the ideXlab platform.
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Proton magnetic resonance spectroscopy of the Substantia nigra in schizophrenia
Schizophrenia Research, 2013Co-Authors: Meredith A Reid, Nina V Kraguljac, Kathy B Avsar, David M White, Jan A. Den Hollander, Adrienne C LahtiAbstract:Abstract Background Converging evidence in schizophrenia points to disruption of the dopamine and glutamate neurotransmitter systems in the pathophysiology of the disorder. Dopamine is produced in the Substantia nigra, but few neuroimaging studies have specifically targeted this structure. In fact, no studies of the Substantia nigra in schizophrenia have used proton magnetic resonance spectroscopy (MRS). We sought to demonstrate the feasibility of acquiring single-voxel MRS measurements at 3 T from the Substantia nigra and to determine which metabolites could be reliably quantified in schizophrenia patients and healthy controls. Methods We used a turbo spin echo sequence with magnetization transfer contrast to visualize the Substantia nigra and single-voxel proton MRS to quantify levels of N -acetylaspartate, glutamate and glutamine (Glx), and choline in the left Substantia nigra of 35 people with schizophrenia and 22 healthy controls. Results We obtained spectra from the Substantia nigra and quantified neurometabolites in both groups. We found no differences in levels of N -acetylaspartate/creatine, Glx/creatine, or choline/creatine between the groups. We found a significant correlation between Glx/creatine and overall cognitive performance, measured with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), in controls but not patients, a difference that was statistically significant. Conclusions Our study demonstrates the feasibility of obtaining single-voxel MRS data from the Substantia nigra in schizophrenia. Such measurements may prove useful in understanding the biochemistry underlying cellular function in a region implicated in the pathophysiology of schizophrenia.
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Proton magnetic resonance spectroscopy of the Substantia nigra in schizophrenia.
Schizophrenia research, 2013Co-Authors: Meredith A Reid, Nina V Kraguljac, Kathy B Avsar, David M White, Jan A Den Hollander, Adrienne C LahtiAbstract:Converging evidence in schizophrenia points to disruption of the dopamine and glutamate neurotransmitter systems in the pathophysiology of the disorder. Dopamine is produced in the Substantia nigra, but few neuroimaging studies have specifically targeted this structure. In fact, no studies of the Substantia nigra in schizophrenia have used proton magnetic resonance spectroscopy (MRS). We sought to demonstrate the feasibility of acquiring single-voxel MRS measurements at 3T from the Substantia nigra and to determine which metabolites could be reliably quantified in schizophrenia patients and healthy controls. We used a turbo spin echo sequence with magnetization transfer contrast to visualize the Substantia nigra and single-voxel proton MRS to quantify levels of N-acetylaspartate, glutamate and glutamine (Glx), and choline in the left Substantia nigra of 35 people with schizophrenia and 22 healthy controls. We obtained spectra from the Substantia nigra and quantified neurometabolites in both groups. We found no differences in levels of N-acetylaspartate/creatine, Glx/creatine, or choline/creatine between the groups. We found a significant correlation between Glx/creatine and overall cognitive performance, measured with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), in controls but not patients, a difference that was statistically significant. Our study demonstrates the feasibility of obtaining single-voxel MRS data from the Substantia nigra in schizophrenia. Such measurements may prove useful in understanding the biochemistry underlying cellular function in a region implicated in the pathophysiology of schizophrenia. Copyright © 2013 Elsevier B.V. All rights reserved.
Meredith A Reid - One of the best experts on this subject based on the ideXlab platform.
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Proton magnetic resonance spectroscopy of the Substantia nigra in schizophrenia
Schizophrenia Research, 2013Co-Authors: Meredith A Reid, Nina V Kraguljac, Kathy B Avsar, David M White, Jan A. Den Hollander, Adrienne C LahtiAbstract:Abstract Background Converging evidence in schizophrenia points to disruption of the dopamine and glutamate neurotransmitter systems in the pathophysiology of the disorder. Dopamine is produced in the Substantia nigra, but few neuroimaging studies have specifically targeted this structure. In fact, no studies of the Substantia nigra in schizophrenia have used proton magnetic resonance spectroscopy (MRS). We sought to demonstrate the feasibility of acquiring single-voxel MRS measurements at 3 T from the Substantia nigra and to determine which metabolites could be reliably quantified in schizophrenia patients and healthy controls. Methods We used a turbo spin echo sequence with magnetization transfer contrast to visualize the Substantia nigra and single-voxel proton MRS to quantify levels of N -acetylaspartate, glutamate and glutamine (Glx), and choline in the left Substantia nigra of 35 people with schizophrenia and 22 healthy controls. Results We obtained spectra from the Substantia nigra and quantified neurometabolites in both groups. We found no differences in levels of N -acetylaspartate/creatine, Glx/creatine, or choline/creatine between the groups. We found a significant correlation between Glx/creatine and overall cognitive performance, measured with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), in controls but not patients, a difference that was statistically significant. Conclusions Our study demonstrates the feasibility of obtaining single-voxel MRS data from the Substantia nigra in schizophrenia. Such measurements may prove useful in understanding the biochemistry underlying cellular function in a region implicated in the pathophysiology of schizophrenia.
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Proton magnetic resonance spectroscopy of the Substantia nigra in schizophrenia.
Schizophrenia research, 2013Co-Authors: Meredith A Reid, Nina V Kraguljac, Kathy B Avsar, David M White, Jan A Den Hollander, Adrienne C LahtiAbstract:Converging evidence in schizophrenia points to disruption of the dopamine and glutamate neurotransmitter systems in the pathophysiology of the disorder. Dopamine is produced in the Substantia nigra, but few neuroimaging studies have specifically targeted this structure. In fact, no studies of the Substantia nigra in schizophrenia have used proton magnetic resonance spectroscopy (MRS). We sought to demonstrate the feasibility of acquiring single-voxel MRS measurements at 3T from the Substantia nigra and to determine which metabolites could be reliably quantified in schizophrenia patients and healthy controls. We used a turbo spin echo sequence with magnetization transfer contrast to visualize the Substantia nigra and single-voxel proton MRS to quantify levels of N-acetylaspartate, glutamate and glutamine (Glx), and choline in the left Substantia nigra of 35 people with schizophrenia and 22 healthy controls. We obtained spectra from the Substantia nigra and quantified neurometabolites in both groups. We found no differences in levels of N-acetylaspartate/creatine, Glx/creatine, or choline/creatine between the groups. We found a significant correlation between Glx/creatine and overall cognitive performance, measured with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), in controls but not patients, a difference that was statistically significant. Our study demonstrates the feasibility of obtaining single-voxel MRS data from the Substantia nigra in schizophrenia. Such measurements may prove useful in understanding the biochemistry underlying cellular function in a region implicated in the pathophysiology of schizophrenia. Copyright © 2013 Elsevier B.V. All rights reserved.
Tulio Becker Hainzenreder - One of the best experts on this subject based on the ideXlab platform.
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Neuromelanin accumulation in Substantia nigra in vascular parkinsonism
Journal of Neural Transmission, 2020Co-Authors: Carlos Eduardo Mantese, Tulio Becker HainzenrederAbstract:Vascular parkinsonism (VaP) is a term used to describe a parkinsonism of vascular cause. However, only ischemic or hemorrhagic lesions in the Substantia nigra or nigrostriatal pathway, leading to a reduction of dopaminergic stimulus are pure VaP. Here, we report a case of true VaP due to nigrostriatal pathway stroke with accumulation of neuromelanin in Substantia nigra. This is the first description of neuromelanin accumulation from nigrostriatal damage. Also, it can help to understand the physiopathological changes in VaP.
David E. Vaillancourt - One of the best experts on this subject based on the ideXlab platform.
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longitudinal changes in free water within the Substantia nigra of parkinson s disease
Brain, 2015Co-Authors: Edward Ofori, Ofer Pasternak, Peggy J Planetta, Roxana G Burciu, Amy Snyder, Song Lai, Michael S Okun, David E. VaillancourtAbstract:There is a clear need to develop non-invasive markers of Substantia nigra progression in Parkinson's disease. We previously found elevated free-water levels in the Substantia nigra for patients with Parkinson's disease compared with controls in single-site and multi-site cohorts. Here, we test the hypotheses that free-water levels in the Substantia nigra of Parkinson's disease increase following 1 year of progression, and that baseline free-water levels in the Substantia nigra predict the change in bradykinesia following 1 year. We conducted a longitudinal study in controls (n = 19) and patients with Parkinson's disease (n = 25). Diffusion imaging and clinical data were collected at baseline and after 1 year. Free-water analyses were performed on diffusion imaging data using blinded, hand-drawn regions of interest in the posterior Substantia nigra. A group effect indicated free-water values were increased in the posterior Substantia nigra of patients with Parkinson's disease compared with controls (P = 0.003) and we observed a significant group × time interaction (P < 0.05). Free-water values increased for the Parkinson's disease group after 1 year (P = 0.006), whereas control free-water values did not change. Baseline free-water values predicted the 1 year change in bradykinesia scores (r = 0.74, P < 0.001) and 1 year change in Montreal Cognitive Assessment scores (r = -0.44, P = 0.03). Free-water in the posterior Substantia nigra is elevated in Parkinson's disease, increases with progression of Parkinson's disease, and predicts subsequent changes in bradykinesia and cognitive status over 1 year. These findings demonstrate that free-water provides a potential non-invasive progression marker of the Substantia nigra.
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Effects of aging on the ventral and dorsal Substantia nigra using diffusion tensor imaging.
Neurobiology of Aging, 2010Co-Authors: David E. Vaillancourt, Matthew B. Spraker, Janey Prodoehl, Xiaohong Joe Zhou, Deborah M. LittleAbstract:Dopaminergic neurons in the Substantia nigra produce dopamine for the nigrostriatal pathway that facilitates motor function. Postmortem examinations demonstrate an age-related loss of cells in the Substantia nigra, with most of the cell loss focused on the dorsal Substantia nigra compared with the ventral Substantia nigra. The current study used diffusion tensor imaging (DTI) to provide the first in vivo assessment of age-related degeneration in specific segments of the Substantia nigra of humans. Measures extracted from DTI of 16 young adults (19-27 years) and 15 older adults (55-71 years) showed that in the dorsal Substantia nigra, fractional anisotropy was reduced and radial diffusivity was increased with age. In the ventral Substantia nigra and red nucleus, there were no differences across age for the DTI measures. DTI provides a noninvasive technique that accurately reflects the established pattern of age-related cell loss in the dorsal and ventral Substantia nigra, further suggesting the robust potential for using DTI to characterize degeneration in the nigrostriatal pathway in both health and disease.
