Quantification of Paramagnetic Ions in Human Brain Tissue Using EPR

Otsuka, Fábio Seiji; Otaduy, Maria Concepción García; Nascimento, Otaciro Rangel; Salmon, Carlos Ernesto Garrido

doi:10.1007/s13538-022-01098-4

Cited by 5 publications

(10 citation statements)

References 52 publications

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“…This broad signal is due to the mineral core in the protein shell of ferritin, in agreement with what has been reported in literature. 13,14,21,22,25 Three narrow signals overlap with the broad spectrum at g ′ = 2.0, 4.3, and 5.8, respectively (arrows). The g ′ = 4.3 and g ′ = 5.8 signals are usually attributed to mononuclear rhombic Fe( iii ) sites 13,21,22,52,82 and high-spin Fe( iii ) in methemoglobin, 83 respectively.…”

Section: Resultsmentioning

confidence: 99%

“…In the past decades, ‘bulk’ magnetometry techniques have been used to characterize the magnetic and mineral state of ferritin, 10,11 along with spectroscopy techniques such as Mössbauer spectroscopy, 11,12 electron paramagnetic resonance (EPR), 13,14 nuclear magnetic resonance (NMR), 15–17 as well as electron and X-ray microscopy techniques, 18,19 and diamond-based quantum spin relaxometry to study the ferritin room temperature magnetic properties. 20 Electron paramagnetic resonance (EPR), sometimes also referred to by the more general term electron magnetic resonance (EMR), has also been applied to ferritin, 13,14,21–25 in spite of intrinsic challenges related to extreme spectral broadening.…”

Section: Introductionmentioning

confidence: 99%

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In-depth magnetometry and EPR analysis of the spin structure of human-liver ferritin: from DC to 9 GHz

Bossoni,

Labra-Muñoz,

van der Zant

et al. 2023

Phys. Chem. Chem. Phys.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

In-depth magnetometry and EPR analysis of the spin structure of human-liver ferritin: from DC to 9 GHz

Bossoni,

Labra-Muñoz,

van der Zant

et al. 2023

Phys. Chem. Chem. Phys.

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“…Copper ions 𝐶𝑢 2+ in freeze-dried brain were found to be described by two values for the diagonalized 𝑔 ⃡ tensor, which indicates an axial symmetry on most cases for the X-band EPR (Barbosa, 2017;Otsuka et al, 2022). This means that resonance occurs mainly at two positions of the spectra, one for the parallel (𝑔 ‖ in the lower field part of the spectrum) and other perpendicular (𝑔 ⊥ in the high field part of the spectrum) components, relative to the applied magnetic field.…”

Section: Electron Paramagnetic Resonance (Epr)mentioning

confidence: 96%

“…The literature involving EPR in brain tissue is scarce, and most of its applications has been on the high-spin iron signal, referred to as the g = 4.3 signal (Kumar et al, 2016;Barbosa, 2017;Bulk et al, 2018). However, it has been observed that typical EPR spectra of lyophilized brain tissue also contains other spectral components, such as copper and a very broad peak at g = 2.01 (Barbosa, 2017;Otsuka et al, 2022) (Figure 8). Interpretation of these paramagnetic components is not straightforward and requires the use of other approaches in order to establish an understanding of their possible molecular sources.…”

Section: Electron Paramagnetic Resonancementioning

confidence: 99%

“…This paramagnetic specie has been attributed to the cellular labile iron pool (LIP) or loosely bound iron (Bou-Abdallah & Chasteen, 2007;Kumar et al, 2016). The EPR features of this system are well-known in the literature and can be better described by incorporating the ZFS effects into the modeling (Kumar et al, 2016;Barbosa, 2017;Otsuka et al, 2022).…”

Section: High-spin 𝑭𝒆 𝟑+ (Rhombic Symmetry)mentioning

confidence: 99%

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Quantification of paramagnetic ions in human brain tissue: correlation to quantitative magnetic resonance imaging

Otsuka

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Imagens Quantitativas por Ressonância Magnética (IRMq) é uma ferramenta promissora na quantificação de ferro na condição in vivo por meio das 𝑅 2 * e Mapeamento Quantitativo de Susceptibilidade Magnética (QSM), contudo a relação desses mapas com o ferro e suas formas moleculares ainda é incerto. Portanto, este estudo busca avaliar a relação entre mapas de 𝑅 2 * e QSM com a concentração de metais medidos por Espectrometria de Massa (ICP-MS) e íons paramagnéticos medidos por Ressonância Paramagnética Eletrônica (RPE). Um total de 15 indivíduos postmortem foram recrutados com mortes por causas não-neurológicas. Imagens postmortem foram processadas em mapas de 𝑅 2 * e QSM, e nove regiões cerebrais relevantes da substância cinzenta foram manualmente segmentadas. Concentrações absolutas de metais e concentrações relativas de íons paramagnéticos foram medidas em cada região. Este estudo corrobora com os achados da literatura, indicando que o ferro é a principal fonte de contraste em regiões dos Núcleos da Base (NB). Contudo, a relação do ferro aparenta ter dependência local, sendo que neste estudo quatro classes de regiões foram identificadas. A primeira classe consiste de regiões com forte correlação com ferro e ferritina. A Segunda classe consiste em regiões parcialmente correlacionados com ferro e ferritina. A Substância Negra compõe a Terceira classe, que mostrou boa correlação com o ferro, porém não com a ferritina. Finalmente, a quarta classe consistiu de estruturas não correlacionadas com o ferro e ferritina. Este estudo indica uma participação heterogênea do ferro no contraste de 𝑅 2 * e QSM entre as diferentes estruturas da substância cinzenta, indicando que regiões com baixa concentração de ferro são influenciadas por outros fatores, além dos investigados neste estudo. Adicionalmente, dentre as estruturas ricas em ferro, diferentes formas moleculares do ferro parecem influenciar o contraste. Especificamente, a Substância Negra mostrou baixa correlação com a ferririna, sugerindo outra forma molecular de ferro responsável pelo contraste.

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Challenges of Continuous Wave EPR of Broad Signals—The Ferritin Case

Otsuka,

García Otaduy,

Nascimento

et al. 2024

Appl Magn Reson

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The study of continuous wave (cw) electron paramagnetic resonance (EPR) spectra still poses a challenge for very broad signals, especially when the spectrum extends over a large part of the accessible field range. The difficulties derive from instrumental challenges, because of insufficient modulation depth and the need to apply measurement conditions that enhance cavity background. The biggest problem, however, is how to define a baseline such that spectral distortions are minimized. Conventional methods rely on a suitable choice of points outside the range of the signal of interest to perform a polynomial interpolation. These methods are effective in most cases where the signal of interest comprises only a narrow range of magnetic field (narrow features). In this study, a novel method of baseline correction for broad signals is proposed and compared to conventional methods. It takes into account that there are only few anchor points for the baseline. The method is applied to the signal of the iron-storage protein ferritin. The ferritin signal is a broad band that extends from zero to 0.8 T. An approach is developed by which this broad signal is analyzed reliably. The method is also extended to the case where the broad signal is superimposed on narrow signals and enables to extract the parameters of both types of signals in a fitting pipeline.

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Quantification of Paramagnetic Ions in Human Brain Tissue Using EPR

Cited by 5 publications

References 52 publications

In-depth magnetometry and EPR analysis of the spin structure of human-liver ferritin: from DC to 9 GHz

In-depth magnetometry and EPR analysis of the spin structure of human-liver ferritin: from DC to 9 GHz

Quantification of paramagnetic ions in human brain tissue: correlation to quantitative magnetic resonance imaging

Challenges of Continuous Wave EPR of Broad Signals—The Ferritin Case

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