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Investigation of the magnetic susceptibility properties of fresh and fixed mouse heart, liver, skeletal muscle and brain tissue. Phys Med 2021; 88:37-44. [PMID: 34171574 DOI: 10.1016/j.ejmp.2021.06.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 06/08/2021] [Accepted: 06/13/2021] [Indexed: 11/22/2022] Open
Abstract
PURPOSE Several magnetic resonance imaging (MRI) techniques exploit the difference in magnetic susceptibilities between tissues, but systematic measurements of tissue susceptibility are lacking. Furthermore, there is the question as to whether chemical fixation that is used for ex vivo MRI studies, affects the magnetic properties of the tissue. Here, we determined the magnetic susceptibility and water content of fresh and chemically fixed mouse tissue. METHODS Mass susceptibility of brain, heart, liver and skeletal muscle samples were determined on a vibrating sample magnetometer at room temperature. Measurements at 50, 125, 200 and 295 K were performed to assess the temperature dependence of susceptibility. Moreover, we measured water content of fresh and fixed samples. RESULTS All samples show mass susceptibilities between -0.068 and -1.929 × 10-8 m3/kg, compared to -9.338 × 10-9 m3/kg of double distilled water. Heart tissue has a more diamagnetic susceptibility than the other tissues. Compared to fresh tissue, fixed tissue has a less diamagnetic susceptibility. Fixed tissue was not different in water content to fresh tissue and showed no consistent dependence of susceptibility with temperature, whereas fresh tissue shows a decrease to at least 125 K, indicative of a paramagnetic component. CONCLUSIONS Biological tissues are diamagnetic in comparison to water, where the heart is more diamagnetic than the other tissues, with paramagnetic contributions. Fixation rendered tissue less diamagnetic compared to fresh tissue. Our measurements revealed differences in tissue susceptibility between VSM and QSM, inviting more research to compare susceptibility-based MRI methods with physical measurements of tissue susceptibility.
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2
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Everett J, Lermyte F, Brooks J, Tjendana-Tjhin V, Plascencia-Villa G, Hands-Portman I, Donnelly JM, Billimoria K, Perry G, Zhu X, Sadler PJ, O'Connor PB, Collingwood JF, Telling ND. Biogenic metallic elements in the human brain? SCIENCE ADVANCES 2021; 7:eabf6707. [PMID: 34108207 PMCID: PMC8189590 DOI: 10.1126/sciadv.abf6707] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 04/22/2021] [Indexed: 05/12/2023]
Abstract
The chemistry of copper and iron plays a critical role in normal brain function. A variety of enzymes and proteins containing positively charged Cu+, Cu2+, Fe2+, and Fe3+ control key processes, catalyzing oxidative metabolism and neurotransmitter and neuropeptide production. Here, we report the discovery of elemental (zero-oxidation state) metallic Cu0 accompanying ferromagnetic elemental Fe0 in the human brain. These nanoscale biometal deposits were identified within amyloid plaque cores isolated from Alzheimer's disease subjects, using synchrotron x-ray spectromicroscopy. The surfaces of nanodeposits of metallic copper and iron are highly reactive, with distinctly different chemical and magnetic properties from their predominant oxide counterparts. The discovery of metals in their elemental form in the brain raises new questions regarding their generation and their role in neurochemistry, neurobiology, and the etiology of neurodegenerative disease.
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Affiliation(s)
- James Everett
- School of Pharmacy and Bioengineering, Guy Hilton Research Centre, Thornburrow Drive, Keele University, Staffordshire ST4 7QB, UK
- School of Engineering, Library Road, University of Warwick, Coventry CV4 7AL, UK
| | - Frederik Lermyte
- School of Engineering, Library Road, University of Warwick, Coventry CV4 7AL, UK
- Department of Chemistry, Technical University of Darmstadt, Alarich-Weiss-Strasse 4, 64287 Darmstadt, Germany
| | - Jake Brooks
- School of Engineering, Library Road, University of Warwick, Coventry CV4 7AL, UK
| | - Vindy Tjendana-Tjhin
- School of Engineering, Library Road, University of Warwick, Coventry CV4 7AL, UK
| | - Germán Plascencia-Villa
- Department of Biology and Neurosciences Institute, The University of Texas at San Antonio (UTSA), San Antonio, TX 78249, USA
| | - Ian Hands-Portman
- School of Life Sciences, Gibbet Hill Campus, University of Warwick, Coventry CV4 7AL, UK
| | - Jane M Donnelly
- School of Engineering, Library Road, University of Warwick, Coventry CV4 7AL, UK
| | - Kharmen Billimoria
- School of Engineering, Library Road, University of Warwick, Coventry CV4 7AL, UK
- Department of Chemistry, Library Road, University of Warwick, Coventry CV4 7AL, UK
- LGC Ltd., Queens Road, Teddington TW11 0LY, UK
| | - George Perry
- Department of Biology and Neurosciences Institute, The University of Texas at San Antonio (UTSA), San Antonio, TX 78249, USA
| | - Xiongwei Zhu
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Peter J Sadler
- Department of Chemistry, Library Road, University of Warwick, Coventry CV4 7AL, UK
| | - Peter B O'Connor
- Department of Chemistry, Library Road, University of Warwick, Coventry CV4 7AL, UK
| | - Joanna F Collingwood
- School of Engineering, Library Road, University of Warwick, Coventry CV4 7AL, UK
| | - Neil D Telling
- School of Pharmacy and Bioengineering, Guy Hilton Research Centre, Thornburrow Drive, Keele University, Staffordshire ST4 7QB, UK.
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Variation in the concentration and regional distribution of magnetic nanoparticles in human brains, with and without Alzheimer's disease, from the UK. Sci Rep 2021; 11:9363. [PMID: 33931662 PMCID: PMC8087805 DOI: 10.1038/s41598-021-88725-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 04/15/2021] [Indexed: 02/08/2023] Open
Abstract
The presence of magnetic nanoparticles (MNPs) in the human brain was attributed until recently to endogenous formation; associated with a putative navigational sense, or with pathological mishandling of brain iron within senile plaques. Conversely, an exogenous, high-temperature source of brain MNPs has been newly identified, based on their variable sizes/concentrations, rounded shapes/surface crystallites, and co-association with non-physiological metals (e.g., platinum, cobalt). Here, we examined the concentration and regional distribution of brain magnetite/maghemite, by magnetic remanence measurements of 147 samples of fresh/frozen tissues, from Alzheimer's disease (AD) and pathologically-unremarkable brains (80-98 years at death) from the Manchester Brain Bank (MBB), UK. The magnetite/maghemite concentrations varied between individual cases, and different brain regions, with no significant difference between the AD and non-AD cases. Similarly, all the elderly MBB brains contain varying concentrations of non-physiological metals (e.g. lead, cerium), suggesting universal incursion of environmentally-sourced particles, likely across the geriatric blood-brain barrier (BBB). Cerebellar Manchester samples contained significantly lower (~ 9×) ferrimagnetic content compared with those from a young (29 years ave.), neurologically-damaged Mexico City cohort. Investigation of younger, variably-exposed cohorts, prior to loss of BBB integrity, seems essential to understand early brain impacts of exposure to exogenous magnetite/maghemite and other metal-rich pollution particles.
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Walsh KJ, Shah SV, Wei P, Oberdick SD, Karn NM, McTigue DM, Agarwal G. Effects of fixatives on histomagnetic evaluation of iron in rodent spleen. JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS 2021; 521:167531. [PMID: 33343059 PMCID: PMC7748249 DOI: 10.1016/j.jmmm.2020.167531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Characterizing the iron distribution in tissue sections is important for several pathologies. Iron content in excised tissue is typically analyzed via histochemical stains, which are dependent on sample preparation and staining protocols. In our recent studies, we examined how magnetic properties of iron can also be exploited to characterize iron distribution in tissue sections in a label free manner. To enable a histomagnetic characterization of iron in a wide variety of available tissues, it is important to extend it to samples routinely prepared for histochemical staining, which often involve use of chemical fixatives. In this study, we took a systematic approach to determine differences between unfixed and formalin-fixed murine spleen tissues in histomagnetic characterization of iron. Superconducting quantum interference device (SQUID) magnetometry and magnetic force microscopy (MFM) were used for macro- and micro-scale histomagnetic characterization. Perl's stain was used for histochemical characterization of ferric (Fe3+) iron on adjacent sections as that used for MFM analysis. While histochemical analysis revealed a substantial difference in the dispersion of the stain between fixed versus unfixed samples, histomagnetic characterization was not dependent on chemical fixation of tissue. The results from this study reveal that histomagnetic characterization of iron is free from staining artifacts which can be present in histochemical analysis.
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Affiliation(s)
| | - Stavan V. Shah
- Department of Biomedical Engineering (The Ohio State University)
| | - Ping Wei
- Department of Neuroscience (The Ohio State University)
| | | | - Nicole M. Karn
- Department of Chemistry and Biochemistry (The Ohio State University)
| | | | - Gunjan Agarwal
- Biophysics Program (The Ohio State University)
- Department of Biomedical Engineering (The Ohio State University)
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5
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van der Weerd L, Lefering A, Webb A, Egli R, Bossoni L. Effects of Alzheimer's disease and formalin fixation on the different mineralised-iron forms in the human brain. Sci Rep 2020; 10:16440. [PMID: 33020534 PMCID: PMC7536241 DOI: 10.1038/s41598-020-73324-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 09/15/2020] [Indexed: 12/18/2022] Open
Abstract
Iron accumulation in the brain is a phenomenon common to many neurodegenerative diseases, perhaps most notably Alzheimer’s disease (AD). We present here magnetic analyses of post-mortem brain tissue of patients who had severe Alzheimer’s disease, and compare the results with those from healthy controls. Isothermal remanent magnetization experiments were performed to assess the extent to which different magnetic carriers are affected by AD pathology and formalin fixation. While Alzheimer’s brain material did not show higher levels of magnetite/maghemite nanoparticles than corresponding controls, the ferrihydrite mineral, known to be found within the core of ferritin proteins and hemosiderin aggregates, almost doubled in concentration in patients with Alzheimer’s pathology, strengthening the conclusions of our previous studies. As part of this study, we also investigated the effects of sample preparation, by performing experiments on frozen tissue as well as tissue which had been fixed in formalin for a period of 5 months. Our results showed that the two different preparations did not critically affect the concentration of magnetic carriers in brain tissue, as observable by SQUID magnetometry.
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Affiliation(s)
- Louise van der Weerd
- Department of Radiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.,Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC, Leiden, The Netherlands
| | - Anton Lefering
- Reactor Institute, Delft University of Technology, Delft, The Netherlands
| | - Andrew Webb
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC, Leiden, The Netherlands
| | - Ramon Egli
- Central Institute for Meteorology and Geo-dynamics (ZAMG), Vienna, Austria
| | - Lucia Bossoni
- Department of Radiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.
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Gorobets S, Radionov O, Kovalev O. Production of Magnetically Controlled Biosorbents Based on Fungi Pleurotus ostreatus. INNOVATIVE BIOSYSTEMS AND BIOENGINEERING 2020. [DOI: 10.20535/ibb.2020.4.2.199367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
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Gonet T, Maher BA. Airborne, Vehicle-Derived Fe-Bearing Nanoparticles in the Urban Environment: A Review. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:9970-9991. [PMID: 31381310 DOI: 10.1021/acs.est.9b01505] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Airborne particulate matter poses a serious threat to human health. Exposure to nanosized (<0.1 μm), vehicle-derived particulates may be hazardous due to their bioreactivity, their ability to penetrate every organ, including the brain, and their abundance in the urban atmosphere. Fe-bearing nanoparticles (<0.1 μm) in urban environments may be especially important because of their pathogenicity and possible association with neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases. This review examines current knowledge regarding the sources of vehicle-derived Fe-bearing nanoparticles, their chemical and mineralogical compositions, grain size distribution and potential hazard to human health. We focus on data reported for the following sources of Fe-bearing nanoparticles: exhaust emissions (both diesel and gasoline), brake wear, tire and road surface wear, resuspension of roadside dust, underground, train and tram emissions, and aircraft and shipping emissions. We identify limitations and gaps in existing knowledge as well as future challenges and perspectives for studies of airborne Fe-bearing nanoparticles.
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Affiliation(s)
- Tomasz Gonet
- Centre for Environmental Magnetism & Palaeomagnetism, Lancaster Environment Centre, Lancaster University , Lancaster LA1 4YQ , United Kingdom
| | - Barbara A Maher
- Centre for Environmental Magnetism & Palaeomagnetism, Lancaster Environment Centre, Lancaster University , Lancaster LA1 4YQ , United Kingdom
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8
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Zheng Y, Cheng J, Dong L, Ma X, Kong Q. Effects of exposure to extremely low frequency electromagnetic fields on hippocampal long-term potentiation in hippocampal CA1 region. Biochem Biophys Res Commun 2019; 517:513-519. [PMID: 31376941 DOI: 10.1016/j.bbrc.2019.07.085] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 07/22/2019] [Indexed: 11/17/2022]
Abstract
Exposure to environmental electromagnetic fields, especially to the extremely low-frequency (ELF < 300 Hz) electromagnetic fields (EMFs) might produce modulation effects on neuronal activity. Long-term changes in synaptic plasticity such as long-term potentiation (LTP) involved in learning and memory may have contributions to a number of neurological diseases. However, the modulation effects of ELF-EMFs on LTP are not yet fully understood. In our present study, we aimed to evaluate the effects of exposure to ELF-EMFs on LTP in hippocampal CA1 region in rats. Hippocampal slices were exposed to magnetic fields generated by sXcELF system with different frequencies (15, 50, and 100 Hz [Hz]), intensities (0.5, 1, and 2 mT [mT]), and duration (10 s [s], 20 s, 40 s, 60 s, and 5 min), then the baseline signal recordings for 20 min and the evoked field excitatory postsynaptic potentials (fEPSPs) were recorded. We found that the LTP amplitudes decreased after magnetic field exposure, and the LTP amplitudes decreased in proportion to exposure doses and durations, suggesting ELF-EMFs may have dose and duration-dependent inhibition effects. Among multiple exposure duration and doses combinations, upon 5 min magnetic field exposure, 15 Hz/2 mT maximally inhibited LTP. Under 15 Hz/2 mT ELF-EMFs, LTP amplitude decreases in proportion to the length of exposure durations within 5 min time frame. Our findings illustrated the potential effects of ELF-EMFs on synaptic plasticity and will lead to better understanding of the influence on learning and memory.
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Affiliation(s)
- Yu Zheng
- School of Electronics and Information Engineering, Tianjin Polytechnic University, Tianjin, 300387, China.
| | - Jianhao Cheng
- School of Electronics and Information Engineering, Tianjin Polytechnic University, Tianjin, 300387, China
| | - Lei Dong
- State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin, 300072, China
| | - Xiaoxu Ma
- School of Electronics and Information Engineering, Tianjin Polytechnic University, Tianjin, 300387, China
| | - Qingyao Kong
- Department of Anesthesia and Critical Care, University of Chicago, Chicago, IL, USA
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9
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Murros K, Wasiljeff J, Macías-Sánchez E, Faivre D, Soinne L, Valtonen J, Pohja M, Saari P, Pesonen LJ, Salminen JM. Magnetic Nanoparticles in Human Cervical Skin. Front Med (Lausanne) 2019; 6:123. [PMID: 31245375 PMCID: PMC6563768 DOI: 10.3389/fmed.2019.00123] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Accepted: 05/16/2019] [Indexed: 01/18/2023] Open
Abstract
Magnetic iron oxide nanoparticles, magnetite/maghemite, have been identified in human tissues, including the brain, meninges, heart, liver, and spleen. As these nanoparticles may play a role in the pathogenesis of neurodegenerative diseases, a pilot study explored the occurrence of these particles in the cervical (neck) skin of 10 patients with Parkinson's disease and 10 healthy controls. Magnetometry and transmission electron microscopy analyses revealed magnetite/maghemite nanoparticles in the skin samples of every study participant. Regarding magnetite/maghemite concentrations of the single-domain particles, no significant between-group difference was emerged. In low-temperature magnetic measurement, a magnetic anomaly at ~50 K was evident mainly in the dermal samples of the Parkinson group. This anomaly was larger than the effect related to the magnetic ordering of molecular oxygen. The temperature range of the anomaly, and the size-range of magnetite/maghemite, both refute the idea of magnetic ordering of any iron phase other than magnetite. We propose that the explanation for the finding is interaction between clusters of superparamagnetic and single-domain-sized nanoparticles. The source and significance of these particles remains speculative.
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Affiliation(s)
- Kari Murros
- Department of Neurology, Helsinki University Hospital, Helsinki, Finland
| | - Joonas Wasiljeff
- Department of Geosciences and Geography, University of Helsinki, Helsinki, Finland
| | - Elena Macías-Sánchez
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Damien Faivre
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany.,CEA, CNRS, BIAM, Aix-Marseille University, Cadarache, France
| | - Lauri Soinne
- Department of Neurology, Helsinki University Hospital, Helsinki, Finland
| | - Jussi Valtonen
- Department of Plastic Surgery, Helsinki University Hospital, Helsinki, Finland
| | - Marjatta Pohja
- Department of Neurology, Helsinki University Hospital, Helsinki, Finland
| | - Pekka Saari
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Lauri J Pesonen
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Johanna M Salminen
- Department of Geosciences and Geography, University of Helsinki, Helsinki, Finland.,Department of Physics, University of Helsinki, Helsinki, Finland
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10
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Finnegan ME, Visanji NP, Romero-Canelon I, House E, Rajan S, Mosselmans JFW, Hazrati LN, Dobson J, Collingwood JF. Synchrotron XRF imaging of Alzheimer's disease basal ganglia reveals linear dependence of high-field magnetic resonance microscopy on tissue iron concentration. J Neurosci Methods 2019; 319:28-39. [PMID: 30851339 DOI: 10.1016/j.jneumeth.2019.03.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 03/02/2019] [Accepted: 03/02/2019] [Indexed: 12/17/2022]
Abstract
BACKGROUND Chemical imaging of the human brain has great potential for diagnostic and monitoring purposes. The heterogeneity of human brain iron distribution, and alterations to this distribution in Alzheimer's disease, indicate iron as a potential endogenous marker. The influence of iron on certain magnetic resonance imaging (MRI) parameters increases with magnetic field, but is under-explored in human brain tissues above 7 T. NEW METHOD Magnetic resonance microscopy at 9.4 T is used to calculate parametric images of chemically-unfixed post-mortem tissue from Alzheimer's cases (n = 3) and healthy controls (n = 2). Iron-rich regions including caudate nucleus, putamen, globus pallidus and substantia nigra are analysed prior to imaging of total iron distribution with synchrotron X-ray fluorescence mapping. Iron fluorescence calibration is achieved with adjacent tissue blocks, analysed by inductively coupled plasma mass spectrometry or graphite furnace atomic absorption spectroscopy. RESULTS Correlated MR images and fluorescence maps indicate linear dependence of R2, R2* and R2' on iron at 9.4 T, for both disease and control, as follows: [R2(s-1) = 0.072[Fe] + 20]; [R2*(s-1) = 0.34[Fe] + 37]; [R2'(s-1) = 0.26[Fe] + 16] for Fe in μg/g tissue (wet weight). COMPARISON WITH EXISTING METHODS This method permits simultaneous non-destructive imaging of most bioavailable elements. Iron is the focus of the present study as it offers strong scope for clinical evaluation; the approach may be used more widely to evaluate the impact of chemical elements on clinical imaging parameters. CONCLUSION The results at 9.4 T are in excellent quantitative agreement with predictions from experiments performed at lower magnetic fields.
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Affiliation(s)
- Mary E Finnegan
- Department of Imaging, Imperial College Healthcare NHS Trust, London, UK; Department of Bioengineering, Imperial College London, London, UK
| | - Naomi P Visanji
- The Edmond J Safra Program in Parkinson's Disease and the Morton & Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, Toronto, Ontario, M5T 2S8, Canada
| | - Isolda Romero-Canelon
- School of Pharmacy, Institute of Clinical Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Emily House
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK
| | - Surya Rajan
- School of Engineering, University of Warwick, Coventry, CV4 7AL, UK
| | | | | | - Jon Dobson
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Joanna F Collingwood
- School of Engineering, University of Warwick, Coventry, CV4 7AL, UK; Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611, USA.
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11
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Distribution of magnetic remanence carriers in the human brain. Sci Rep 2018; 8:11363. [PMID: 30054530 PMCID: PMC6063936 DOI: 10.1038/s41598-018-29766-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 07/18/2018] [Indexed: 11/11/2022] Open
Abstract
That the human brain contains magnetite is well established; however, its spatial distribution in the brain has remained unknown. We present room temperature, remanent magnetization measurements on 822 specimens from seven dissected whole human brains in order to systematically map concentrations of magnetic remanence carriers. Median saturation remanent magnetizations from the cerebellum were approximately twice as high as those from the cerebral cortex in all seven cases (statistically significantly distinct, p = 0.016). Brain stems were over two times higher in magnetization on average than the cerebral cortex. The ventral (lowermost) horizontal layer of the cerebral cortex was consistently more magnetic than the average cerebral cortex in each of the seven studied cases. Although exceptions existed, the reproducible magnetization patterns lead us to conclude that magnetite is preferentially partitioned in the human brain, specifically in the cerebellum and brain stem.
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12
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Kobayashi A, Horikawa M, Kirschvink JL, Golash HN. Magnetic control of heterogeneous ice nucleation with nanophase magnetite: Biophysical and agricultural implications. Proc Natl Acad Sci U S A 2018; 115:5383-5388. [PMID: 29735681 PMCID: PMC6003474 DOI: 10.1073/pnas.1800294115] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
In supercooled water, ice nucleation is a stochastic process that requires ∼250-300 molecules to transiently achieve structural ordering before an embryonic seed crystal can nucleate. This happens most easily on crystalline surfaces, in a process termed heterogeneous nucleation; without such surfaces, water droplets will supercool to below -30 °C before eventually freezing homogeneously. A variety of fundamental processes depends on heterogeneous ice nucleation, ranging from desert-blown dust inducing precipitation in clouds to frost resistance in plants. Recent experiments have shown that crystals of nanophase magnetite (Fe3O4) are powerful nucleation sites for this heterogeneous crystallization of ice, comparable to other materials like silver iodide and some cryobacterial peptides. In natural materials containing magnetite, its ferromagnetism offers the possibility that magneto-mechanical motion induced by external oscillating magnetic fields could act to disrupt the water-crystal interface, inhibiting the heterogeneous nucleation process in subfreezing water and promoting supercooling. For this to act, the magneto-mechanical rotation of the particles should be higher than the magnitude of Brownian motions. We report here that 10-Hz precessing magnetic fields, at strengths of 1 mT and above, on ∼50-nm magnetite crystals dispersed in ultrapure water, meet these criteria and do indeed produce highly significant supercooling. Using these rotating magnetic fields, we were able to elicit supercooling in two representative plant and animal tissues (celery and bovine muscle), both of which have detectable, natural levels of ferromagnetic material. Tailoring magnetic oscillations for the magnetite particle size distribution in different tissues could maximize this supercooling effect.
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Affiliation(s)
- Atsuko Kobayashi
- Earth-Life Science Institute, Tokyo Institute of Technology, Meguro, 152-8550 Tokyo, Japan;
| | - Masamoto Horikawa
- Department of Systems and Control Engineering, Tokyo Institute of Technology, Meguro, 152-8552 Tokyo, Japan
| | - Joseph L Kirschvink
- Earth-Life Science Institute, Tokyo Institute of Technology, Meguro, 152-8550 Tokyo, Japan
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125
| | - Harry N Golash
- Robotics Institute, Carnegie Mellon University, Pittsburgh, PA 15213
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13
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Iron Biochemistry is Correlated with Amyloid Plaque Morphology in an Established Mouse Model of Alzheimer's Disease. Cell Chem Biol 2017; 24:1205-1215.e3. [PMID: 28890316 DOI: 10.1016/j.chembiol.2017.07.014] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 01/19/2017] [Accepted: 07/28/2017] [Indexed: 11/21/2022]
Abstract
A signature characteristic of Alzheimer's disease (AD) is aggregation of amyloid-beta (Aβ) fibrils in the brain. Nevertheless, the links between Aβ and AD pathology remain incompletely understood. It has been proposed that neurotoxicity arising from aggregation of the Aβ1-42 peptide can in part be explained by metal ion binding interactions. Using advanced X-ray microscopy techniques at sub-micron resolution, we investigated relationships between iron biochemistry and AD pathology in intact cortex from an established mouse model over-producing Aβ. We found a direct correlation of amyloid plaque morphology with iron, and evidence for the formation of an iron-amyloid complex. We also show that iron biomineral deposits in the cortical tissue contain the mineral magnetite, and provide evidence that Aβ-induced chemical reduction of iron could occur in vivo. Our observations point to the specific role of iron in amyloid deposition and AD pathology, and may impact development of iron-modifying therapeutics for AD.
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14
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Gorobets O, Gorobets S, Koralewski M. Physiological origin of biogenic magnetic nanoparticles in health and disease: from bacteria to humans. Int J Nanomedicine 2017; 12:4371-4395. [PMID: 28652739 PMCID: PMC5476634 DOI: 10.2147/ijn.s130565] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The discovery of biogenic magnetic nanoparticles (BMNPs) in the human brain gives a strong impulse to study and understand their origin. Although knowledge of the subject is increasing continuously, much remains to be done for further development to help our society fight a number of pathologies related to BMNPs. This review provides an insight into the puzzle of the physiological origin of BMNPs in organisms of all three domains of life: prokaryotes, archaea, and eukaryotes, including humans. Predictions based on comparative genomic studies are presented along with experimental data obtained by physical methods. State-of-the-art understanding of the genetic control of biomineralization of BMNPs and their properties are discussed in detail. We present data on the differences in BMNP levels in health and disease (cancer, neurodegenerative disorders, and atherosclerosis), and discuss the existing hypotheses on the biological functions of BMNPs, with special attention paid to the role of the ferritin core and apoferritin.
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Affiliation(s)
- Oksana Gorobets
- National Technical University of Ukraine (Igor Sikorsky Kyiv Polytechnic Institute)
- Institute of Magnetism, National Academy of Sciences, Kiev, Ukraine
| | - Svitlana Gorobets
- National Technical University of Ukraine (Igor Sikorsky Kyiv Polytechnic Institute)
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15
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Kumar P, Bulk M, Webb A, van der Weerd L, Oosterkamp TH, Huber M, Bossoni L. A novel approach to quantify different iron forms in ex-vivo human brain tissue. Sci Rep 2016; 6:38916. [PMID: 27941952 PMCID: PMC5150947 DOI: 10.1038/srep38916] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 11/14/2016] [Indexed: 01/28/2023] Open
Abstract
We propose a novel combination of methods to study the physical properties of ferric ions and iron-oxide nanoparticles in post-mortem human brain, based on the combination of Electron Paramagnetic Resonance (EPR) and SQUID magnetometry. By means of EPR, we derive the concentration of the low molecular weight iron pool, as well as the product of its electron spin relaxation times. Additionally, by SQUID magnetometry we identify iron mineralization products ascribable to a magnetite/maghemite phase and a ferrihydrite (ferritin) phase. We further derive the concentration of magnetite/maghemite and of ferritin nanoparticles. To test out the new combined methodology, we studied brain tissue of an Alzheimer’s patient and a healthy control. Finally, we estimate that the size of the magnetite/maghemite nanoparticles, whose magnetic moments are blocked at room temperature, exceeds 40–50 nm, which is not compatible with the ferritin protein, the core of which is typically 6–8 nm. We believe that this methodology could be beneficial in the study of neurodegenerative diseases such as Alzheimer’s Disease which are characterized by abnormal iron accumulation in the brain.
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Affiliation(s)
- Pravin Kumar
- Huygens-Kamerlingh Onnes Laboratory, Leiden University, 2333 CA Leiden, The Netherlands
| | - Marjolein Bulk
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.,Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Andrew Webb
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Louise van der Weerd
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.,Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Tjerk H Oosterkamp
- Huygens-Kamerlingh Onnes Laboratory, Leiden University, 2333 CA Leiden, The Netherlands
| | - Martina Huber
- Huygens-Kamerlingh Onnes Laboratory, Leiden University, 2333 CA Leiden, The Netherlands
| | - Lucia Bossoni
- Huygens-Kamerlingh Onnes Laboratory, Leiden University, 2333 CA Leiden, The Netherlands
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16
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Kobayashi A, Golash HN, Kirschvink JL. A first test of the hypothesis of biogenic magnetite-based heterogeneous ice-crystal nucleation in cryopreservation. Cryobiology 2016; 72:216-24. [PMID: 27087604 DOI: 10.1016/j.cryobiol.2016.04.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 04/05/2016] [Accepted: 04/10/2016] [Indexed: 10/22/2022]
Abstract
An outstanding biophysical puzzle is focused on the apparent ability of weak, extremely low-frequency oscillating magnetic fields to enhance cryopreservation of many biological tissues. A recent theory holds that these weak magnetic fields could be inhibiting ice-crystal nucleation on the nanocrystals of biological magnetite (Fe3O4, an inverse cubic spinel) that are present in many plant and animal tissues by causing them to oscillate. In this theory, magnetically-induced mechanical oscillations disrupt the ability of water molecules to nucleate on the surface of the magnetite nanocrystals. However, the ability of the magnetite crystal lattice to serve as a template for heterogeneous ice crystal nucleation is as yet unknown, particularly for particles in the 10-100 nm size range. Here we report that the addition of trace-amounts of finely-dispersed magnetite into ultrapure water samples reduces strongly the incidence of supercooling, as measured in experiments conducted using a controlled freezing apparatus with multiple thermocouples. SQUID magnetometry was used to quantify nanogram levels of magnetite in the water samples. We also report a relationship between the volume change of ice, and the degree of supercooling, that may indicate lower degassing during the crystallization of supercooled water. In addition to supporting the role of ice-crystal nucleation by biogenic magnetite in many tissues, magnetite nanocrystals could provide inexpensive, non-toxic, and non-pathogenic ice nucleating agents needed in a variety of industrial processes, as well as influencing the dynamics of ice crystal nucleation in many natural environments.
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Affiliation(s)
- Atsuko Kobayashi
- Earth-Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan.
| | - Harry N Golash
- Division of Mechanical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Joseph L Kirschvink
- Earth-Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan; Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
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17
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Abstract
Iron is an essential element for fundamental cell functions and a catalyst for chemical reactions. Three samples extracted from the human spleen were investigated by scanning (SEM) and transmission electron microscopy (TEM), Mössbauer spectrometry (MS), and SQUID magnetometry. The sample with diagnosis of hemosiderosis (H) differs from that referring to hereditary spherocytosis and the reference sample. SEM reveals iron-rich micrometer-sized aggregate of various structures-tiny fibrils in hereditary spherocytosis sample and no fibrils in hemochromatosis. Hematite and magnetite particles from 2 to 6 μm in TEM with diffraction in all samples were shown. The SQUID magnetometry shows different amount of diamagnetic, paramagnetic and ferrimagnetic structures in the tissues. The MS results indicate contribution of ferromagnetically split sextets for all investigated samples. Their occurrence indicates that at least part of the sample is magnetically ordered below the critical temperature. The iron accumulation process is different in hereditary spherocytosis and hemosiderosis. This fact may be the reason of different iron crystallization.
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18
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Bouten S, Pantecouteau H, Debruille JB. Looking for effects of qualia on event-related brain potentials of close others in search for a cause of the similarity of qualia assumed across individuals. F1000Res 2014; 3:316. [PMID: 29910945 PMCID: PMC5992535 DOI: 10.12688/f1000research.5977.3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/31/2018] [Indexed: 11/22/2022] Open
Abstract
Qualia, the individual instances of subjective conscious experience, are private events. However, in everyday life, we assume qualia of others and their perceptual worlds, to be similar to ours. One way this similarity is possible is if qualia of others somehow contribute to the production of qualia by our own brain and vice versa. To test this hypothesis, we focused on the mean voltages of event-related potentials (ERPs) in the time-window of the P600 component, whose amplitude correlates positively with conscious awareness. These ERPs were elicited by images of the international affective picture system in 16 pairs of friends, siblings or couples going side by side through hyperscanning without having to interact. Each of the 32 members of these 16 pairs faced one half of the screen and could not see what the other member was presented with on the other half. One stimulus occurred on each half simultaneously. The sameness of these stimulus pairs was manipulated as well as the participants’ belief in that sameness by telling subjects’ pairs that they were going to be presented with the same stimuli in two blocks and with different ones in the two others. ERPs were more positive at all electrode subsets for stimulus pairs that were
inconsistent with the belief than for those that were consistent. In the N400 time window, at frontal electrode sites, ERPs were again more positive for inconsistent than for consistent stimuli. As participants had no way to see the stimulus their partner was presented with and thus no way to detect inconsistence, these data might reveal an impact of the qualia of a person on the brain activity of another. Such impact could provide a research avenue when trying to explain the similarity of qualia across individuals.
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Affiliation(s)
- Sheila Bouten
- Douglas Mental Health University Institute, Montréal, Québec, H4H 1R3, Canada
| | | | - J Bruno Debruille
- Douglas Mental Health University Institute, Montréal, Québec, H4H 1R3, Canada.,Department of Neurology and Neurosurgery, McGill University, Montréal, Québec, H3A 2B4, Canada.,Department of Psychiatry, McGill University, Montréal, Québec, H3A 1A1, Canada
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19
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Kobayashi A, Kirschvink JL. A ferromagnetic model for the action of electric and magnetic fields in cryopreservation. Cryobiology 2014; 68:163-5. [DOI: 10.1016/j.cryobiol.2013.12.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 10/04/2013] [Accepted: 12/03/2013] [Indexed: 10/25/2022]
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20
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Melnikova L, Pospiskova K, Mitroova Z, Kopcansky P, Safarik I. Peroxidase-like activity of magnetoferritin. Mikrochim Acta 2013. [DOI: 10.1007/s00604-013-1105-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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21
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Gorobets SV, Gorobets OY, Chyzh YM, Sivenok DV. Magnetic dipole interaction of endogenous magnetic nanoparticles with magnetoliposomes for targeted drug delivery. Biophysics (Nagoya-shi) 2013. [DOI: 10.1134/s000635091303007x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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22
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Castellani RJ, Moreira PI, Perry G, Zhu X. The role of iron as a mediator of oxidative stress in Alzheimer disease. Biofactors 2012; 38:133-8. [PMID: 22447715 DOI: 10.1002/biof.1010] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 02/03/2012] [Indexed: 01/31/2023]
Abstract
Iron is both essential for maintaining a spectrum of metabolic processes in the central nervous system and elsewhere, and potent source of reactive oxygen species. Redox balance with respect to iron, therefore, may be critical to human neurodegenerative disease but is also in need of better understanding. Alzheimer disease (AD) in particular is associated with accumulation of numerous markers of oxidative stress; moreover, oxidative stress has been shown to precede hallmark neuropathological lesions early in the disease process, and such lesions, once present, further accumulate iron, among other markers of oxidative stress. In this review, we discuss the role of iron in the progression of AD.
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Affiliation(s)
- Rudy J Castellani
- Department of Pathology, University of Maryland, Baltimore, MD, USA.
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23
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Antharam V, Collingwood JF, Bullivant JP, Davidson MR, Chandra S, Mikhaylova A, Finnegan ME, Batich C, Forder JR, Dobson J. High field magnetic resonance microscopy of the human hippocampus in Alzheimer's disease: quantitative imaging and correlation with iron. Neuroimage 2012; 59:1249-60. [PMID: 21867761 PMCID: PMC3690369 DOI: 10.1016/j.neuroimage.2011.08.019] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 08/01/2011] [Accepted: 08/06/2011] [Indexed: 11/21/2022] Open
Abstract
We report R(2) and R(2) in human hippocampus from five unfixed post-mortem Alzheimer's disease (AD) and three age-matched control cases. Formalin-fixed tissues from opposing hemispheres in a matched AD and control were included for comparison. Imaging was performed in a 600MHz (14T) vertical bore magnet at MR microscopy resolution to obtain R(2) and R(2) (62 μm×62 μm in-plane, 80 μm slice thickness), and R(1) at 250 μm isotropic resolution. R(1), R(2) and R(2) maps were computed for individual slices in each case, and used to compare subfields between AD and controls. The magnitudes of R(2) and R(2) changed very little between AD and control, but their variances in the Cornu Ammonis and dentate gyrus were significantly higher in AD compared for controls (p<0.001). To investigate the relationship between tissue iron and MRI parameters, each tissue block was cryosectioned at 30 μm in the imaging plane, and iron distribution was mapped using synchrotron microfocus X-ray fluorescence spectroscopy. A positive correlation of R(2) and R(2)* with iron was demonstrated. While studies with fixed tissues are more straightforward to conduct, fixation can alter iron status in tissues, making measurement of unfixed tissue relevant. To our knowledge, these data represent an advance in quantitative imaging of hippocampal subfields in unfixed tissue, and the methods facilitate direct analysis of the relationship between MRI parameters and iron. The significantly increased variance in AD compared for controls warrants investigation at lower fields and in-vivo, to determine if this parameter is clinically relevant.
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Affiliation(s)
- Vijay Antharam
- Department of Medicine, University of Florida, Gainesville, FL, USA
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24
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Long-term memory in brain magnetite. Med Hypotheses 2010; 74:254-7. [DOI: 10.1016/j.mehy.2009.09.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Accepted: 09/11/2009] [Indexed: 11/21/2022]
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25
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26
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Stewart Z, Martinac B, Dobson J. EVIDENCE FOR MECHANOSENSITIVE TRANSMEMBRANE ION CHANNELS OF SMALL CONDUCTANCE IN MAGNETOTACTIC BACTERIA. ACTA ACUST UNITED AC 2009. [DOI: 10.1081/jbc-100100298] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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27
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3D morphology of the human hepatic ferritin mineral core: new evidence for a subunit structure revealed by single particle analysis of HAADF-STEM images. J Struct Biol 2008; 166:22-31. [PMID: 19116170 PMCID: PMC2832756 DOI: 10.1016/j.jsb.2008.12.001] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Revised: 12/02/2008] [Accepted: 12/03/2008] [Indexed: 11/23/2022]
Abstract
Ferritin, the major iron storage protein, has dual functions; it sequesters redox activity of intracellular iron and facilitates iron turn-over. Here we present high angle annular dark field (HAADF) images from individual hepatic ferritin cores within tissue sections, these images were obtained using spherical aberration corrected scanning transmission electron microscopy (STEM) under controlled electron fluence. HAADF images of the cores suggest a cubic morphology and a polycrystalline (ferrihydrite) subunit structure that is not evident in equivalent bright field images. By calibrating contrast levels in the HAADF images using quantitative electron energy loss spectroscopy, we have estimated the absolute iron content in any one core, and produced a three dimensional reconstruction of the average core morphology. The core is composed of up to eight subunits, consistent with the eight channels in the protein shell that deliver iron to the central cavity. We find no evidence of a crystallographic orientation relationship between core subunits. Our results confirm that the ferritin protein shell acts as a template for core morphology and within the core, small (approximately 2 nm), surface-disordered ferrihydrite subunits connect to leave a low density centre and a high surface area that would allow rapid turn-over of iron in biological systems.
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28
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Affiliation(s)
- Damien Faivre
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
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29
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Castellani RJ, Moreira PI, Liu G, Dobson J, Perry G, Smith MA, Zhu X. Iron: the Redox-active center of oxidative stress in Alzheimer disease. Neurochem Res 2007; 32:1640-5. [PMID: 17508283 DOI: 10.1007/s11064-007-9360-7] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Accepted: 04/17/2007] [Indexed: 01/24/2023]
Abstract
Although iron is essential in maintaining the function of the central nervous system, it is a potent source of reactive oxygen species. Excessive iron accumulation occurs in many neurodegenerative diseases including Alzheimer disease (AD), Parkinson's disease, and Creutzfeldt-Jakob disease, raising the possibility that oxidative stress is intimately involved in the neurodegenerative process. AD in particular is associated with accumulation of numerous markers of oxidative stress; moreover, oxidative stress has been shown to precede hallmark neuropathological lesions early in the disease process, and such lesions, once present, further accumulate iron, among other markers of oxidative stress. In this review, we discuss the role of iron in the progression of AD.
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30
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Brem F, Hirt AM, Winklhofer M, Frei K, Yonekawa Y, Wieser HG, Dobson J. Magnetic iron compounds in the human brain: a comparison of tumour and hippocampal tissue. J R Soc Interface 2007; 3:833-41. [PMID: 17015303 PMCID: PMC1885366 DOI: 10.1098/rsif.2006.0133] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Iron is a central element in the metabolism of normal and malignant cells. Abnormalities in iron and ferritin expression have been observed in many types of cancer. Interest in characterizing iron compounds in the human brain has increased due to advances in determining a relationship between excess iron accumulation and neurological and neurodegenerative diseases. In this work, four different magnetic methods have been employed to characterize the iron phases and magnetic properties of brain tumour (meningiomas) tissues and non-tumour hippocampal tissues. Four main magnetic components can be distinguished: the diamagnetic matrix, nearly paramagnetic blood, antiferromagnetic ferrihydrite cores of ferritin and ferrimagnetic magnetite and/or maghemite. For the first time, open hysteresis loops have been observed on human brain tissue at room temperature. The hysteresis properties indicate the presence of magnetite and/or maghemite particles that exhibit stable single-domain (SD) behaviour at room temperature. A significantly higher concentration of magnetically ordered magnetite and/or maghemite and a higher estimated concentration of heme iron was found in the meningioma samples. First-order reversal curve diagrams on meningioma tissue further show that the stable SD particles are magnetostatically interacting, implying high-local concentrations (clustering) of these particles in brain tumours. These findings suggest that brain tumour tissue contains an elevated amount of remanent iron oxide phases.
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Affiliation(s)
- Franziska Brem
- Institute of GeophysicsETH-Hönggerberg, 8093 Zurich, Switzerland
| | - Ann M Hirt
- Institute of GeophysicsETH-Hönggerberg, 8093 Zurich, Switzerland
- Author for correspondence ()
| | - Michael Winklhofer
- Department of Earth and Environmental Science, University of Munich80333 München, Germany
| | - Karl Frei
- Department of Neurosurgery, University Hospital Zurich8091 Zurich, Switzerland
| | - Yasuhiro Yonekawa
- Department of Neurosurgery, University Hospital Zurich8091 Zurich, Switzerland
| | | | - Jon Dobson
- Institute for Science & Technology in Medicine, Keele UniversityStoke-on-Trent ST4 7QB, UK
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31
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Hirt AM, Brem F, Hanzlik M, Faivre D. Anomalous magnetic properties of brain tissue at low temperature: The 50 K anomaly. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2006jb004570] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Ann M. Hirt
- Institute of Geophysics; ETH-Zürich; Zürich Switzerland
| | | | - Marianne Hanzlik
- Technische Chemie 1; Technische Universität München; Gärching Germany
| | - Damien Faivre
- Max Planck Institute for Marine Microbiology; Bremen Germany
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32
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Hautot D, Pankhurst QA, Morris CM, Curtis A, Burn J, Dobson J. Preliminary observation of elevated levels of nanocrystalline iron oxide in the basal ganglia of neuroferritinopathy patients. Biochim Biophys Acta Mol Basis Dis 2006; 1772:21-5. [PMID: 17097860 PMCID: PMC1993816 DOI: 10.1016/j.bbadis.2006.09.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2006] [Revised: 09/26/2006] [Accepted: 09/28/2006] [Indexed: 11/16/2022]
Abstract
Magnetometry analysis of brain tissue sub-samples from two neuroferritinopathy patients provides a preliminary indication that the amount of magnetic iron compounds associated with this rare disease is significantly larger than in age/sex-matched controls. The primary iron compounds contributing to the remnant magnetization of the tissue above 50 K and at body temperature are both blocked and superparamagnetic (SPM) biogenic magnetite (Fe3O4) and/or maghemite (gamma-Fe2O3). The concentration of SPM magnetite is significant and appears to be proportional to the concentration of ferritin, which varies with progression of the disease. The mutated ferritin protein appears to be responsible for the presence of iron oxide nano-particules, which in turn could be responsible for extensive damage in the brain.
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Affiliation(s)
- Dimitri Hautot
- Institute of Science and Technology in Medicine, Keele University, Stoke on Trent, and Institute for Aging and Health, Newcastle General Hospital, Newcastle upon Tyne, UK.
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Mikhaylova A, Davidson M, Toastmann H, Channell J, Guyodo Y, Batich C, Dobson J. Detection, identification and mapping of iron anomalies in brain tissue using X-ray absorption spectroscopy. J R Soc Interface 2006; 2:33-7. [PMID: 16849161 PMCID: PMC1578259 DOI: 10.1098/rsif.2004.0011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This work describes a novel method for the detection, identification and mapping of anomalous iron compounds in mammalian brain tissue using X-ray absorption spectroscopy. We have located and identified individual iron anomalies in an avian tissue model associated with ferritin, biogenic magnetite and haemoglobin with a pixel resolution of less than 5 microm. This technique represents a breakthrough in the study of both intra- and extra-cellular iron compounds in brain tissue. The potential for high-resolution iron mapping using microfocused X-ray beams has direct application to investigations of the location and structural form of iron compounds associated with human neurodegenerative disorders--a problem which has vexed researchers for 50 years.
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Affiliation(s)
- A Mikhaylova
- Biomedical Engineering Department, University of FloridaP.O. Box 116400, Gainesville, FL 32611, USA
| | - M Davidson
- Department of Materials Science and Engineering, University of FloridaP.O. Box 116400, Gainesville, FL 32611, USA
| | - H Toastmann
- MRCAT Beamline, Advanced Photon Source, Argonne National Laboratory9700 S. Cass Avenue, Argonne, IL 60439, USA
| | - J.E.T Channell
- Department of Geological Sciences, University of FloridaGainesville, FL 32611, USA
| | - Y Guyodo
- Institute for Rock Magnetism291 Shepherd Labs, 100 Union Street S.E., Minneapolis, MN 55455, USA
| | - C Batich
- Biomedical Engineering Department, University of FloridaP.O. Box 116400, Gainesville, FL 32611, USA
- Department of Materials Science and Engineering, University of FloridaP.O. Box 116400, Gainesville, FL 32611, USA
| | - J Dobson
- Institute for Science and Technology in Medicine, Keele UniversityThornburrow Drive, Hartshill, Stoke-on-Trent ST4 7QB, UK
- Author for correspondence. ()
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Gutiérrez L, Lázaro FJ, Abadía AR, Romero MS, Quintana C, Puerto Morales M, Patiño C, Arranz R. Bioinorganic transformations of liver iron deposits observed by tissue magnetic characterisation in a rat model. J Inorg Biochem 2006; 100:1790-9. [PMID: 16899298 DOI: 10.1016/j.jinorgbio.2006.06.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2006] [Revised: 06/20/2006] [Accepted: 06/25/2006] [Indexed: 12/22/2022]
Abstract
The magnetic properties and the ultrastructure, with special emphasis on the nanometric range, of liver tissues in an iron overload rat model have been investigated. The tissues of the animals, sacrificed at different times after a single iron dextran injection, have been characterised by magnetic AC susceptibility measurements together with transmission electron microscopy (TEM) and selected area electron diffraction (SAED) as helping techniques. It has been observed that few days after the iron administration the liver contains at least two iron species: (i) akaganéite nanoparticles, coming from iron dextran and (ii) ferrihydrite nanoparticles corresponding to ferritin. The magnetic susceptibility of the tissues depends not only on the elemental iron content but also on its distribution among chemical species, and varies in a remarkable regular manner as a function of the elapsed time since the iron administration. The results are of relevance with respect to non-invasive techniques for liver iron determination, directly or indirectly based on the magnetic susceptibility of the tissues, as biomagnetic liver susceptometry (BLS) and magnetic resonance (MRI) image treatment.
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Affiliation(s)
- Lucía Gutiérrez
- Departamento de Ciencia y Tecnología de Materiales y Fluidos, Universidad de Zaragoza, 50018 Zaragoza, Spain
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35
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Wieraszko A, Ahmed Z, Armani J, Maqsood N, Philips S, Raja H. Neurophysiological Effects Induced in the Nervous Tissue by Low-Frequency, Pulsed Magnetic Fields. ACTA ACUST UNITED AC 2005. [DOI: 10.1007/s10669-005-4277-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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36
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Collingwood JF, Mikhaylova A, Davidson MR, Batich C, Streit WJ, Eskin T, Terry J, Barrea R, Underhill RS, Dobson J. High-resolution x-ray absorption spectroscopy studies of metal compounds in neurodegenerative brain tissue. ACTA ACUST UNITED AC 2005. [DOI: 10.1088/1742-6596/17/1/009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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37
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Brem F, Hirt AM, Simon C, Wieser HG, Dobson J. Low temperature magnetic analysis in the identification of iron compounds from human brain tumour tissue. ACTA ACUST UNITED AC 2005. [DOI: 10.1088/1742-6596/17/1/010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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38
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Brem F, Hirt AM, Simon C, Wieser HG, Dobson J. Characterization of iron compounds in tumour tissue from temporal lobe epilepsy patients using low temperature magnetic methods. Biometals 2005; 18:191-7. [PMID: 15954745 DOI: 10.1007/s10534-004-6253-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Excess iron accumulation in the brain has been shown to be related to a variety of neurodegenerative diseases. However, identification and characterization of iron compounds in human tissue is difficult because concentrations are very low. For the first time, a combination of low temperature magnetic methods was used to characterize iron compounds in tumour tissue from patients with mesial temporal lobe epilepsy (MTLE). Induced magnetization as a function of temperature was measured between 2 and 140 K after cooling in zero-field and after cooling in a 50 mT field. These curves reveal an average blocking temperature for ferritin of 10 K and an anomaly due to magnetite at 48 K. Hysteresis measurements at 5 K show a high coercivity phase that is unsaturated at 7 T, which is typical for ferritin. Magnetite concentration was determined from the saturation remanent magnetization at 77 K. Hysteresis measurements at various temperatures were used to examine the magnetic blocking of magnetite and ferritin. Our results demonstrate that low temperature magnetic measurements provide a useful and sensitive tool for the characterisation of magnetic iron compounds in human tissue.
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Affiliation(s)
- Franziska Brem
- ETH-Hönggerberg, Institute of Geophysics, CH-8093 Zurich, Switzerland.
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Fuller M, Dobson J. On the significance of the time constants of magnetic field sensitivity in animals. Bioelectromagnetics 2005; 26:234-7. [PMID: 15768423 DOI: 10.1002/bem.20102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A variety of organisms is known to have the ability to transduce and respond to relatively weak magnetic fields, including the earth's field. Though biogenic magnetite has been identified as the transducer in a number of cases with regards to geomagnetic field sensing, the mechanism underlying neurophysiological responses in human studies is not understood. Here we note that the time constants involved in this latter type of field sensitivity are much longer than those in organisms that make use of the earth's magnetic field for navigation. The purpose of this brief communication is to suggest that the time constants associated with magnetic field sensitivity may be a useful way to distinguish field sensitivity due to magnetite based receptors from sensitivity that may depend on direct (or downstream) biochemical processes.
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Affiliation(s)
- Mike Fuller
- Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, Honolulu, Hawaii, USA
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Wieraszko A. Amplification of evoked potentials recorded from mouse hippocampal slices by very low repetition rate pulsed magnetic fields. Bioelectromagnetics 2005; 25:537-44. [PMID: 15376238 DOI: 10.1002/bem.20044] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The influence of low repetition rate pulsed magnetic fields (LRMF) on the evoked potential (population spike) recorded from mouse hippocampal slices was investigated. LRMF were applied according to two protocols. In protocol A, LRMF applied with a constant strength (15 mT) and frequency ranging from 0.03 to 0.5 Hz resulted in an amplification of the potential. Although the frequency of 0.16 Hz was the most effective, enhancing the population spike by over 280%, it also caused an increase in spontaneous activity, seizures, and cessation of neuronal activity in 50% of the slices. In protocol B, LRMF were applied with a variable intensity (9-15 mT) and in cycles of different duration ranging from 5 to 20 min. While an increase in the amplitude of the population spike was observed in all slices exposed to LRMF applied according to protocol B, the longest exposure was the most effective. Neither seizures nor an increase in the spontaneous activity were observed in this group of the slices. These results support and extend our previous data and characterize further the relation between the pattern of applied magnetic fields and their influence on the nervous system.
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Affiliation(s)
- Andrzej Wieraszko
- Department of Biology/Program in Neuroscience, The College of Staten Island/CUNY, Staten Island, NY 10314, USA.
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Hogan MV, Wieraszko A. An increase in cAMP concentration in mouse hippocampal slices exposed to low-frequency and pulsed magnetic fields. Neurosci Lett 2004; 366:43-7. [PMID: 15265587 DOI: 10.1016/j.neulet.2004.05.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2004] [Revised: 05/06/2004] [Accepted: 05/06/2004] [Indexed: 10/26/2022]
Abstract
Our previous studies revealed that magnetic fields amplified evoked potentials recorded from mouse hippocampal slices. In search for the mechanism of this effect, we evaluated the concentration of cAMP in slices exposed to low-frequency and pulsed magnetic fields. Low-frequency magnetic fields of 15 mT applied at 0.16 Hz for 30 min enhanced the concentration of cAMP almost three-fold. The concentration of cAMP continued to rise through the first hour after turning magnetic fields off, reaching almost a four-fold increase, and then returned to control levels at the end of the second hour. Neither static magnetic fields nor magnetic fields applied with the frequency of 0.5 Hz had any effect on cAMP concentration. The increase in cAMP levels was dependent on the strength of the magnetic field and required the presence of extracellular calcium. A pulsed magnetic field applied with variable intensity (9-15 mT) and in cycles lasting from 5 to 20 min doubled the cAMP concentration. These results support our previous electrophysiological observations and provide biochemical correlates for their interpretation.
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Affiliation(s)
- Michael V Hogan
- Clinical Laboratory Sciences, College of Allied Health Professions, University of South Alabama, SHAC 2309, 1504 Springhill Avenue, Mobile, AL 36604, USA
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Quintana C, Cowley JM, Marhic C. Electron nanodiffraction and high-resolution electron microscopy studies of the structure and composition of physiological and pathological ferritin. J Struct Biol 2004; 147:166-78. [PMID: 15193645 DOI: 10.1016/j.jsb.2004.03.001] [Citation(s) in RCA: 150] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2003] [Revised: 02/26/2004] [Indexed: 11/25/2022]
Abstract
Structures of core nanocrystals of physiological (horse spleen, human liver, and brain) and pathological human brain of patients with progressive supranuclear palsy (PSP) and Alzheimer's disease (AD) ferritin molecules were determined using electron nanodiffraction and high-resolution transmission electron microscopy. The poly-phasic structure of the ferritin cores is confirmed. There are significant differences in the mineral composition between the physiological and pathological ferritins. The physiological ferritin cores mainly consist of single nanocrystals containing hexagonal ferrihydrite (Fh) and hematite (Hm) and some cubic magnetite/maghemite phase. In the pathological cores, Fh is present but only as a minor phase and Hm is absent. The major phases are a face-centered-cubic (fcc) structure with a = 0.43 nm and a high degree of disorder, related to wustite, and a cubic magnetite-like structure. These two cubic phases are also present in human aged normal brain. Evidence for the presence of hemosiderin together with ferritin in the pathological brains is deduced from the similarities of the diffraction patterns with those from patients with primary hemochromatosis, and differences in the shapes and protein composition of the protein shell. These findings suggest a disfunction of the ferritin associated with PSP and AD, associated with an increase in the concentration of brain ferrous toxic iron.
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Affiliation(s)
- C Quintana
- Instituto de Microelectrónica de Madrid. C.S.I.C., 8 Isaac Newton, PTM, 28760 Tres Cantos, Madrid, Spain.
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Abstract
Although iron plays an important role in many aspects of human neurophysiology, it also can be toxic under certain circumstances. Anomalous amounts of iron are known to be associated with most types of neurodegenerative disorders such as Alzheimer's, Parkinson's, and Huntington's diseases. To date, little is known about the specific iron compounds present in this tissue and there is recent evidence to suggest that some forms are magnetic. This raises important questions with regard to the role of magnetic iron compounds in disease initiation and progression and, indeed, the origin of these compounds. This paper reviews recent work on the identification and analysis of magnetic iron compounds associated with neurological disorders.
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Affiliation(s)
- Jon Dobson
- Centre for Science and Technology in Medicine, Keele University, Hartshill, Stoke-on-Trent, United Kingdom.
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Wieser HG. Future aspects of epilepsy research. ACTA NEUROCHIRURGICA. SUPPLEMENT 2003; 84:1-16. [PMID: 12379000 DOI: 10.1007/978-3-7091-6117-3_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
This contribution in honour of Prof. Gerhard Pendl first reviews some recent studies on resected tissue, migrational disorders, and Rasmussen's Syndrome. These areas of basic research profit from recent advances of molecular biology and genetics. On the clinical side, some studies dealing with proton magnetic resonance spectroscopy are reviewed. In order to highlight the progress in clinical epilepsy research using modern methods of structural and functional imaging, functional outcome prediction is also reviewed. This kind of advanced clinical research is dealt with by discussing risk factor assessment associated with postsurgical decrements in memory. With regard to motor functions, we compare the yield of functional MR and intraoperative cortical stimulation in patients with lesions in or close to the Rolandic cortex. Progress in the field of advanced EEG analysis is reviewed in the context of "seizure prediction" and cognitive event-related potentials. Finally some of the new epilepsy treatment options, such as Gamma Knife treatment, where Prof. Pendl's group made pioneering contributions, are dealt with.
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Affiliation(s)
- H G Wieser
- Neurology Clinic, Dept. Epileptology and Electroencephalography, University Hospital, Zurich, Switzerland
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Pardoe H, Chua-anusorn W, St Pierre TG, Dobson J. Detection limits for ferrimagnetic particle concentrations using magnetic resonance imaging based proton transverse relaxation rate measurements. Phys Med Biol 2003; 48:N89-95. [PMID: 12699196 DOI: 10.1088/0031-9155/48/6/401] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A clinical magnetic resonance imaging (MRI) system was used to measure proton transverse relaxation rates (R2) in agar gels with varying concentrations of ferrimagnetic iron oxide nanoparticles in a field strength of 1.5 T. The nanoparticles were prepared by coprecipitation of ferric and ferrous ions in the presence of either dextran or polyvinyl alcohol. The method of preparation resulted in loosely packed clusters (dextran) or branched chains (polyvinyl alcohol) of particles containing of the order of 600 and 400 particles, respectively. For both methods of particle preparation, concentrations of ferrimagnetic iron in agar gel less than 0.01 mg ml(-1) had no measurable effect on the value of R2 for the gel. The results indicate that MRI-based R2 measurements using 1.5 T clinical scanners are not quite sensitive enough to detect the very low concentrations of nanoparticulate biogenic magnetite reported in human brain tissue.
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Affiliation(s)
- H Pardoe
- School of Physics, The University of Western Australia, Crawley, Perth, WA 6009, Australia
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Sastre A, Graham C, Cook MR, Gerkovich MM, Gailey P. Human EEG responses to controlled alterations of the Earth's magnetic field. Clin Neurophysiol 2002; 113:1382-90. [PMID: 12169319 DOI: 10.1016/s1388-2457(02)00186-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVES Examine the effects of controlled changes in the Earth's magnetic field on electroencephalogram (EEG) and subjective report. METHODS Fifty volunteers were exposed double-blind to changes in field magnitude, angle of inclination, and angle of deviation. Volunteers were also exposed to magnetic field conditions found near the North and South Pole. EEG recorded over temporal and occipital sites was compared across 4s baseline, field exposure, and no-change control trials. RESULTS No EEG spectral differences as a function of gender or recording site were found. Geomagnetic field alterations had no effect on total energy (0.5-42 Hz), energy within traditional EEG analysis bands, or on the 95% spectral edge. Most volunteers reported no sensations; others reported non-specific symptoms unrelated to type of field change. DISCUSSION Three hypothesized field detection mechanisms were not supported: (1) mechanical reception through torque exerted on the ferromagnetic material magnetite; (2) movement-induced induction of an electric field in the body; and (3) enhanced sensitivity due to alterations in the rates of chemical reactions involving electron spin states. CONCLUSIONS Humans have little ability to detect brief alterations in the geomagnetic field, even if these alteration are of a large magnitude.
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Affiliation(s)
- Antonio Sastre
- Midwest Research Institute, 425 Volker Boulevard, Kansas City, MO 64110, USA.
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Abstract
One of the characteristics of many neurodegenerative diseases is the disruption of normal iron homeostasis in the brain. Recent experimental work indicates that nanoscale magnetic biominerals (primarily magnetite and maghemite) may be associated with senile plaques and tau filaments found in brain tissue affected by these diseases. These findings have important implications for our understanding of the role of iron in neurodegenerative disease as well as profound implications for their causes. In addition, the presence of biogenic magnetite in affected tissue should also provide improved mechanisms for early detection through the modification of MRI pulse sequences.
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Affiliation(s)
- J Dobson
- Centre for Science and Technology in Medicine, Department of Biomedical Engineering and Medical Physics, Keele University, Thornburrow Drive, Hartshill, Stroke-on-Trent ST4 7QB, UK.
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Abstract
Direct current-generated magnetic fields (2-3 mT, 20-min exposure) exerted biphasic effects on the population spike recorded from hippocampal slices. The initial decrease in the potential, observed during exposure of the slices to magnetic fields was followed by a recovery/amplification phase, which began after terminating the magnetic field action. During that phase the population spike exceeded the amplitude observed before application of the magnetic fields. The pattern of magnetic fields influence was not affected either by (+)-5-methyl-10,11-dihydro-5H-dibenzo (a,d) cyclohepten-5, 10-imine maleate (MK801), or by D,L,-2amino-5phosphonovalerate (APV), a noncompetitive and competitive NMDA receptor antagonist, respectively. The rising phase of the potential, however, was eliminated by dantrolene, an inhibitor of intracellular Ca(2 +) channels. This suggests that intracellular calcium channels participate in the mechanism of the influence of the direct current magnetic fields on the function of the hippocampal tissue.
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Affiliation(s)
- A Wieraszko
- CSI/IBR Center for Developmental Neuroscience and Developmental Disabilities, and Department of Biology, College of Staten Island/CUNY, Staten Island, New York 10314, USA.
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Dobson J, St Pierre T, Wieser HG, Fuller M. Changes in paroxysmal brainwave patterns of epileptics by weak-field magnetic stimulation. Bioelectromagnetics 2000; 21:94-9. [PMID: 10653619 DOI: 10.1002/(sici)1521-186x(200002)21:2<94::aid-bem3>3.0.co;2-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In order to assess the effects of weak-field magnetic stimulation on brain electrical activity in epileptics, three patients suffering from mesial temporal lobe epilepsy (MTLE) were exposed to DC magnetic fields of 0.9 and 1.8 millitesla (mT). The EEG activity was recorded simultaneously from intracranial electrodes inserted through the foramen ovale (FO) and scalp electrodes. Significant enhancement of interictal epileptiform activity was observed in two patients, while in one patient, magnetic stimulation resulted in the cessation of interictal spike/wave trains.
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Affiliation(s)
- J Dobson
- Department of Chemistry and UF Brain Institute, University of Florida, Gainesville 32611, USA.
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Chignell CF, Sik RH. Effect of Magnetite Particles on Photoinduced and Nonphotoinduced Free Radical Processes in Human Erythrocytes. Photochem Photobiol 1998. [DOI: 10.1111/j.1751-1097.1998.tb02520.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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