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https://www.readbyqxmd.com/read/28019018/contrast-mechanisms-associated-with-neuromelanin-mri
#1
Paula Trujillo, Paul E Summers, Emanuele Ferrari, Fabio A Zucca, Michela Sturini, Luca T Mainardi, Sergio Cerutti, Alex K Smith, Seth A Smith, Luigi Zecca, Antonella Costa
PURPOSE: To investigate the physical mechanisms associated with the contrast observed in neuromelanin MRI. METHODS: Phantoms having different concentrations of synthetic melanins with different degrees of iron loading were examined on a 3 Tesla scanner using relaxometry and quantitative magnetization transfer (MT). RESULTS: Concentration-dependent T1 and T2 shortening was most pronounced for the melanin pigment when combined with iron. Metal-free melanin had a negligible effect on the magnetization transfer spectra...
December 26, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28004859/parkinson-s-disease-related-increase-of-t2-weighted-hypointensity-in-substantia-nigra-pars-compacta
#2
Jason Langley, Daniel E Huddleston, Jan Sedlacik, Kai Boelmans, Xiaoping P Hu
BACKGROUND: In PD, at the time of diagnosis, approximately 50% of melanized dopaminergic neurons in SNpc have died, yet ongoing neuronal death and neuromelanin release with associated neuroinflammation and microglial activation continue, as does local iron accumulation. Previous studies investigating nigral iron accumulation used T2 / T2*-weighted contrasts to define the regions of interest in the SN. Given that T2 / T2*-weighted contrasts lack sensitivity to neuromelanin and thereby SNpc, neuromelanin-sensitive MRI provides better delineation of SNpc and allows the examination of increased iron deposition in SNpc more specifically and accurately...
December 22, 2016: Movement Disorders: Official Journal of the Movement Disorder Society
https://www.readbyqxmd.com/read/27997036/pathologic-correlations-of-f-18-av-1451-imaging-in-non-alzheimer-tauopathies
#3
Marta Marquié, Marc D Normandin, Avery C Meltzer, Michael Siao Tick Chong, Nicolas V Andrea, Alejandro Antón-Fernández, William E Klunk, Chester A Mathis, Milos D Ikonomovic, Manik Debnath, Elizabeth A Bien, Charles R Vanderburg, Isabel Costantino, Sara Makaretz, Sarah L DeVos, Derek H Oakley, Stephen N Gomperts, John H Growdon, Kimiko Domoto-Reilly, Diane Lucente, Bradford C Dickerson, Matthew P Frosch, Bradley T Hyman, Keith A Johnson, Teresa Gómez-Isla
OBJECTIVE: Recent studies have shown that PET tracer AV-1451 exhibits high binding affinity for paired helical filament (PHF)-tau pathology in Alzheimer's brains. However, the ability of this ligand to bind to tau lesions in other tauopathies remains controversial. Our goal was to examine the correlation of in vivo and postmortem AV-1451 binding patterns in three autopsy-confirmed non-Alzheimer tauopathy cases. METHODS: We quantified in vivo retention of [F-18]-AV-1451 and performed autoradiography, [H-3]-AV-1451 binding assays and quantitative tau measurements in postmortem brain samples from two Progressive Supranuclear Palsy (PSP) cases and a MAPT P301L mutation carrier...
December 20, 2016: Annals of Neurology
https://www.readbyqxmd.com/read/27993708/subtypes-evaluation-of-motor-dysfunction-in-parkinson-s-disease-using-neuromelanin-sensitive-magnetic-resonance-imaging
#4
Yuanyuan Xiang, Tao Gong, Junwei Wu, Jifeng Li, Yan Chen, Yongxiang Wang, Shan Li, Lin Cong, Youting Lin, Yuxiang Han, Ling Yin, Guangbin Wang, Yifeng Du
Parkinson's disease (PD) is characterized by the loss of neuromelanin (NM)-containing neurons in the substantia nigra pars compacta (SNc), and it is divided into two motor subtypes: the postural instability gait difficulty (PIGD) and the tremor dominant (TD) subtypes. With NM-sensitive Magnetic Resonance Imaging (NM-MRI), investigators have been able to accurately detect signal attenuation in SNc of PD; however, the difference of NM loss between PIGD and TD subtypes is still unclear. Thus, the aim of this study was to evaluate the differences in NM-MRI between PD motor subtypes...
December 16, 2016: Neuroscience Letters
https://www.readbyqxmd.com/read/27820685/in-vivo-assessment-of-brainstem-depigmentation-in-parkinson-disease-potential-as-a-severity-marker-for-multicenter-studies
#5
Stefan T Schwarz, Yue Xing, Pragya Tomar, Nin Bajaj, Dorothee P Auer
Purpose To investigate the pattern of neuromelanin signal intensity loss within the substantia nigra pars compacta (SNpc), locus coeruleus, and ventral tegmental area in Parkinson disease (PD); the specific aims were (a) to study regional magnetic resonance (MR) quantifiable depigmentation in association with PD severity and (b) to investigate whether imaging- and platform-dependent signal intensity variations can be normalized. Materials and Methods This prospective case-control study was approved by the local ethics committee and the research department of Nottingham University Hospitals...
November 7, 2016: Radiology
https://www.readbyqxmd.com/read/27813160/subcortical-18-f-av-1451-binding-patterns-in-progressive-supranuclear-palsy
#6
Hanna Cho, Jae Yong Choi, Mi Song Hwang, Seung Ha Lee, Young Hoon Ryu, Myung Sik Lee, Chul Hyoung Lyoo
BACKGROUND: Accumulation of cortical and subcortical tau pathology is the primary pathological substrate for progressive supranuclear palsy (PSP). (18) F-AV-1451, a radiotracer that binds to the pathological tau protein, may be helpful for in vivo visualization and quantitation of tau pathology in PSP. OBJECTIVES: The objectives of this study were to investigate cortical and subcortical (18) F-AV-1451 binding patterns in patients with PSP. METHODS: We recruited 14 PSP patients and compared their cortical and subcortical binding patterns in (18) F-AV-1451 positron emission tomography (PET) studies with those of 15 Parkinson's disease (PD) patients and 15 healthy controls...
November 3, 2016: Movement Disorders: Official Journal of the Movement Disorder Society
https://www.readbyqxmd.com/read/27769419/combined-in-situ-imaging-of-structural-organization-and-elemental-composition-of-substantia-nigra-neurons-in-the-elderly
#7
A D Surowka, M Töpperwien, M Bernhardt, J D Nicolas, M Osterhoff, T Salditt, D Adamek, M Szczerbowska-Boruchowska
Human dopaminergic system in general, and substantia nigra (SN) neurons, in particular, are implicated in the pathologies underlying the human brain aging. The interplay between aberrations in the structural organization and elemental composition of SN neuron bodies has recently gained in importance as selected metals: Fe, Cu, Zn, Ca were found to trigger oxidative-stress-mediated aberration in their molecular assembly due to concomitant protein (alpha-synuclein, tau-protein) aggregation, gliosis and finally oxidative stress...
December 1, 2016: Talanta
https://www.readbyqxmd.com/read/27768782/quantitative-t1-t2-and-t2-mapping-and-semi-quantitative-neuromelanin-sensitive-magnetic-resonance-imaging-of-the-human-midbrain
#8
Takashi Hashido, Shigeyoshi Saito
PURPOSE: Neuromelanin is a dark pigment granule present within certain catecholamine neurons of the human brain. Here, we aimed to clarify the relationship between contrast of neuromelanin-sensitive magnetic resonance imaging (MRI) and MR relaxation times using T1, T2, and T2* mapping of the lower midbrain. METHODS: The subjects were 14 healthy volunteers (11 men and 3 women, mean age 29.9 ± 6.9 years). Neuromelanin-sensitive MRI was acquired using an optimized T1-weighted two-dimensional (2D)-turbo spin-echo sequence...
2016: PloS One
https://www.readbyqxmd.com/read/27756668/near-infrared-confocal-laser-reflectance-cytoarchitectural-imaging-of-the-substantia-nigra-and-cerebellum-in-the-fresh-human-cadaver
#9
Cletus Cheyuo, Walter Grand, Lucia L Balos
BACKGROUND: Cytoarchitectural neuroimaging remains critical for diagnosis of many brain diseases. Fluorescent dye-enhanced, near-infrared confocal in situ cellular imaging of the brain has been reported. However, impermeability of the blood-brain barrier to most fluorescent dyes limits clinical utility of this modality. The differential degree of reflectance from brain tissue with unenhanced near-infrared imaging may represent an alternative technique for in situ cytoarchitectural neuroimaging...
October 15, 2016: World Neurosurgery
https://www.readbyqxmd.com/read/27687624/reproducibility-of-locus-coeruleus-and-substantia-nigra-imaging-with-neuromelanin-sensitive-mri
#10
Jason Langley, Daniel E Huddleston, Christine J Liu, Xiaoping Hu
OBJECTIVES: The purpose of this study was to assess the reproducibility of substantia nigra pars compacta (SNpc) and locus coeruleus (LC) delineation and measurement with neuromelanin-sensitive MRI. MATERIALS AND METHODS: Eleven subjects underwent two neuromelanin-sensitive MRI scans. SNpc and LC volumes were extracted for each scan. Reproducibility of volume and magnetization transfer contrast measurements in SNpc and LC was assessed using intraclass correlation coefficients (ICC) and dice similarity coefficients (DSC)...
September 29, 2016: Magma
https://www.readbyqxmd.com/read/27662849/saturation-binding-of-nicotine-to-synthetic-neuromelanin-demonstrated-by-fluorescence-spectroscopy
#11
Robert L Haining, Travis M Jones, Aubrey Hernandez
Neuromelanin (NM) has long been considered as an aging pigment, perhaps an unavoidable and undesirable byproduct of dopaminergic neural transmission. However, NM is carefully packaged into double membrane-bound structures within cells of the substantia nigra and other neural tissues, suggesting a beneficial function to maintaining these stores. It is well established that NM is able to concentrate toxic xenobiotics within pigmented cells due to its unique chemical environment. In doing so, such agents may confer susceptibility to Parkinson's disease (PD) as illustrated by model PD-inducing neurotoxins such as methyl-phenyl-pyridinium ion...
December 2016: Neurochemical Research
https://www.readbyqxmd.com/read/27640074/rare-variants-analysis-of-cutaneous-malignant-melanoma-genes-in-parkinson-s-disease
#12
S J Lubbe, V Escott-Price, A Brice, T Gasser, A M Pittman, J Bras, J Hardy, P Heutink, N M Wood, A B Singleton, D G Grosset, C B Carroll, M H Law, F Demenais, M M Iles, D T Bishop, J Newton-Bishop, N M Williams, H R Morris
A shared genetic susceptibility between cutaneous malignant melanoma (CMM) and Parkinson's disease (PD) has been suggested. We investigated this by assessing the contribution of rare variants in genes involved in CMM to PD risk. We studied rare variation across 29 CMM risk genes using high-quality genotype data in 6875 PD cases and 6065 controls and sought to replicate findings using whole-exome sequencing data from a second independent cohort totaling 1255 PD cases and 473 controls. No statistically significant enrichment of rare variants across all genes, per gene, or for any individual variant was detected in either cohort...
December 2016: Neurobiology of Aging
https://www.readbyqxmd.com/read/27619539/a-longitudinal-study-of-neuromelanin-sensitive-magnetic-resonance-imaging-in-parkinson-s-disease
#13
Keita Matsuura, Masayuki Maeda, Ken-Ichi Tabei, Maki Umino, Hiroyuki Kajikawa, Masayuki Satoh, Hirotaka Kida, Hidekazu Tomimoto
PURPOSE: Neuromelanin-sensitive MR imaging (NMI) is an increasingly powerful tool for the diagnosis of Parkinson's disease (PD). This study was undertaken to evaluate longitudinal changes on NMI in PD patients. METHODS: We examined longitudinal changes on NMI in 14 PD patients. The area and contrast ratio (CR) of the substantia nigra pars compacta (SNc) were comparatively analyzed. RESULTS: The total area and CR of the SNc upon follow-up NMI were significantly smaller than those on initial NMI (from 33...
October 28, 2016: Neuroscience Letters
https://www.readbyqxmd.com/read/27597825/neuromelanin-imaging-and-dopaminergic-loss-in-parkinson-s-disease
#14
Ioannis U Isaias, Paula Trujillo, Paul Summers, Giorgio Marotta, Luca Mainardi, Gianni Pezzoli, Luigi Zecca, Antonella Costa
Parkinson's disease (PD) is a progressive neurodegenerative disorder in which the major pathologic substrate is a loss of dopaminergic neurons from the substantia nigra. Our main objective was to determine the correspondence between changes in the substantia nigra, evident in neuromelanin and iron sensitive magnetic resonance imaging (MRI), and dopaminergic striatal innervation loss in patients with PD. Eighteen patients and 18 healthy control subjects were included in the study. Using neuromelanin-MRI, we measured the volume of the substantia nigra and the contrast-to-noise-ratio between substantia nigra and a background region...
2016: Frontiers in Aging Neuroscience
https://www.readbyqxmd.com/read/27596274/the-neuromelanin-related-t2-contrast-in-postmortem-human-substantia-nigra-with-7t-mri
#15
Jae-Hyeok Lee, Sun-Yong Baek, YoungKyu Song, Sujeong Lim, Hansol Lee, Minh Phuong Nguyen, Eun-Joo Kim, Gi Yeong Huh, Se Young Chun, HyungJoon Cho
High field magnetic resonance imaging (MRI)-based delineation of the substantia nigra (SN) and visualization of its inner cellular organization are promising methods for the evaluation of morphological changes associated with neurodegenerative diseases; however, corresponding MR contrasts must be matched and validated with quantitative histological information. Slices from two postmortem SN samples were imaged with a 7 Tesla (7T) MRI with T1 and T2* imaging protocols and then stained with Perl's Prussian blue, Kluver-Barrera, tyrosine hydroxylase, and calbindin immunohistochemistry in a serial manner...
2016: Scientific Reports
https://www.readbyqxmd.com/read/27587951/a-comparison-of-substantia-nigra-t1-hyperintensity-in-parkinson-s-disease-dementia-alzheimer-s-disease-and-age-matched-controls-volumetric-analysis-of-neuromelanin-imaging
#16
Won-Jin Moon, Ju-Yeon Park, Won-Sung Yun, Ji Yeong Jeon, Yeon Sil Moon, Heejin Kim, Ki-Chang Kwak, Jong-Min Lee, Seol-Heui Han
OBJECTIVE: Neuromelanin loss of substantia nigra (SN) can be visualized as a T1 signal reduction on T1-weighted high-resolution imaging. We investigated whether volumetric analysis of T1 hyperintensity for SN could be used to differentiate between Parkinson's disease dementia (PDD), Alzheimer's disease (AD) and age-matched controls. MATERIALS AND METHODS: This retrospective study enrolled 10 patients with PDD, 18 patients with AD, and 13 age-matched healthy elderly controls...
September 2016: Korean Journal of Radiology: Official Journal of the Korean Radiological Society
https://www.readbyqxmd.com/read/27494668/neural-differentiation-in-the-third-dimension-generating-a-human-midbrain
#17
Rebecca M Marton, Sergiu P Paşca
In recent years, technological improvements in three-dimensional (3D) culture systems have enabled the generation of organoids or spheroids representing a variety of tissues, including the brain. In this issue of Cell Stem Cell, Jo et al. (2016) describe a 3D culture model of the human midbrain containing dopaminergic neurons and neuromelanin.
August 4, 2016: Cell Stem Cell
https://www.readbyqxmd.com/read/27476966/midbrain-like-organoids-from-human-pluripotent-stem-cells-contain-functional-dopaminergic-and-neuromelanin-producing-neurons
#18
Junghyun Jo, Yixin Xiao, Alfred Xuyang Sun, Engin Cukuroglu, Hoang-Dai Tran, Jonathan Göke, Zi Ying Tan, Tzuen Yih Saw, Cheng-Peow Tan, Hidayat Lokman, Younghwan Lee, Donghoon Kim, Han Seok Ko, Seong-Oh Kim, Jae Hyeon Park, Nam-Joon Cho, Thomas M Hyde, Joel E Kleinman, Joo Heon Shin, Daniel R Weinberger, Eng King Tan, Hyunsoo Shawn Je, Huck-Hui Ng
Recent advances in 3D culture systems have led to the generation of brain organoids that resemble different human brain regions; however, a 3D organoid model of the midbrain containing functional midbrain dopaminergic (mDA) neurons has not been reported. We developed a method to differentiate human pluripotent stem cells into a large multicellular organoid-like structure that contains distinct layers of neuronal cells expressing characteristic markers of human midbrain. Importantly, we detected electrically active and functionally mature mDA neurons and dopamine production in our 3D midbrain-like organoids (MLOs)...
August 4, 2016: Cell Stem Cell
https://www.readbyqxmd.com/read/27333324/rab7-induces-clearance-of-%C3%AE-synuclein-aggregates
#19
Elisabeth Dinter, Theodora Saridaki, Markus Nippold, Sarah Plum, Leonie Diederichs, Daniel Komnig, Luisa Fensky, Caroline May, Katrin Marcus, Aaron Voigt, Jörg B Schulz, Björn H Falkenburger
Parkinson's disease can be caused by mutations in the α-synuclein gene and is characterized by aggregates of α-synuclein protein. Aggregates are degraded by the autophago-lysosomal pathway. Since Rab7 has been shown to regulate trafficking of late endosomes and autophagosomes, we hypothesized that over-expressing Rab7 might be beneficial in Parkinson's disease. To test this hypothesis, we expressed the pathogenic A53T mutant of α-synuclein in HEK293 cells and Drosophila melanogaster. In HEK293 cells, EGFP-Rab7-decorated vesicles contain α-synuclein...
September 2016: Journal of Neurochemistry
https://www.readbyqxmd.com/read/27311820/melanin-and-neuromelanin-binding-of-drugs-and-chemicals-toxicological-implications
#20
REVIEW
Oskar Karlsson, Nils Gunnar Lindquist
Melanin is a polyanionic pigment that colors, e.g., the hair, skin and eyes. The pigment neuromelanin is closely related to melanin and is mainly produced in specific neurons of the substantia nigra. Certain drugs and chemicals bind to melanin/neuromelanin and are retained in pigment cells for long periods. This specific retention is thought to protect the cells but also to serve as a depot that slowly releases accumulated compounds and may cause toxicity in the eye and skin. Moreover, neuromelanin and compounds with high neuromelanin affinity have been suggested to be implicated in the development of adverse drug reactions in the central nervous system (CNS) as well as in the etiology of Parkinson's disease (PD)...
August 2016: Archives of Toxicology
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