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Cheng L, Wang M, Yang B, Li Y, Wang T, Xi C, Han Y, Wang Z, Fang Y, Wei M, Du H, Xu A. Ultra-high static magnetic fields altered the embryonic division and development in Caenorhabditis elegans via multipolar spindles. J Adv Res 2024:S2090-1232(24)00316-3. [PMID: 39089616 DOI: 10.1016/j.jare.2024.07.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/31/2024] [Accepted: 07/29/2024] [Indexed: 08/04/2024] Open
Abstract
INTRODUCTION Ultra-high static magnetic fields (SMFs) have unique advantages in improving medical and academic research. However, the research on the early embryo exposure of ultra-high SMFs is minimal, extensive exploration is indispensable in living organisms. OBJECTIVES The present study was aimed to study the effects of ultra-high SMFs on the early embryonic division and development of Caenorhabditis elegans (C. elegans). METHODS Early adult parents containing fertilized eggs in vivo were exposed to SMFs at intensities ranging from 4 T to 27 T. The number of mitotic cells in the reproductive glands of the P0 worms, early embryonic cell spindle localization, embryo hatching and the reproductive as well as developmental indicators of F1 and F2 nematodes were examined as endpoints. RESULTS Our results indicated that ultra-high SMFs has no obvious effect on the germ cell cycle, while 14 T and 27 T SMFs significantly increased the proportion of multi-polar spindle formation in early embryonic cells, and reduced the developmental rate and lifespan of C. elegans exposed at the embryonic stage. Spindle abnormalities of early embryonic cells, as well as the down-regulation of genes related to asymmetric embryonic division and the abnormal expression of the non-muscle myosin NMY-2 in the division grooves played a critical role in the slowing down of embryonic development induced by ultra-high SMFs. CONCLUSIONS This study provided novel information and a new sight for evaluating the biosafety assessment by exposure to ultra-high SMFs at the early embryonic stage in vivo.
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Affiliation(s)
- Lei Cheng
- Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Anhui Province Key Laboratory of Environmental Toxicology and Pollution Control Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China; School of Environmental Science and Optoelectronic Technology, University of Science and Technology of China, Hefei, Anhui 230026, PR China
| | - Mudi Wang
- School of Basic Medical Science, Anhui Medical University, Hefei, Anhui 230032, PR China
| | - Baolin Yang
- Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Anhui Province Key Laboratory of Environmental Toxicology and Pollution Control Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China; School of Environmental Science and Optoelectronic Technology, University of Science and Technology of China, Hefei, Anhui 230026, PR China
| | - Yang Li
- Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Anhui Province Key Laboratory of Environmental Toxicology and Pollution Control Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China; School of Environmental Science and Optoelectronic Technology, University of Science and Technology of China, Hefei, Anhui 230026, PR China
| | - Tong Wang
- Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Anhui Province Key Laboratory of Environmental Toxicology and Pollution Control Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China
| | - Chuanying Xi
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China
| | - Yuyan Han
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China
| | - Ze Wang
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China
| | - Yanwen Fang
- Heye Health Technology Co.,Ltd., Huzhou, Zhejiang 313300, PR China
| | - Min Wei
- Heye Health Technology Co.,Ltd., Huzhou, Zhejiang 313300, PR China
| | - Hua Du
- Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Anhui Province Key Laboratory of Environmental Toxicology and Pollution Control Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China
| | - An Xu
- Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Anhui Province Key Laboratory of Environmental Toxicology and Pollution Control Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China; School of Environmental Science and Optoelectronic Technology, University of Science and Technology of China, Hefei, Anhui 230026, PR China.
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Ji X, Tian X, Feng S, Zhang L, Wang J, Guo R, Zhu Y, Yu X, Zhang Y, Du H, Zablotskii V, Zhang X. Intermittent F-actin Perturbations by Magnetic Fields Inhibit Breast Cancer Metastasis. RESEARCH (WASHINGTON, D.C.) 2023; 6:0080. [PMID: 36939445 PMCID: PMC10017101 DOI: 10.34133/research.0080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 01/31/2023] [Indexed: 02/04/2023]
Abstract
F-actin (filamentous actin) has been shown to be sensitive to mechanical stimuli and play critical roles in cell attachment, migration, and cancer metastasis, but there are very limited ways to perturb F-actin dynamics with low cell toxicity. Magnetic field is a noninvasive and reversible physical tool that can easily penetrate cells and human bodies. Here, we show that 0.1/0.4-T 4.2-Hz moderate-intensity low-frequency rotating magnetic field-induced electric field could directly decrease F-actin formation in vitro and in vivo, which results in decreased breast cancer cell migration, invasion, and attachment. Moreover, low-frequency rotating magnetic fields generated significantly different effects on F-actin in breast cancer vs. noncancerous cells, including F-actin number and their recovery after magnetic field retrieval. Using an intermittent treatment modality, low-frequency rotating magnetic fields could significantly reduce mouse breast cancer metastasis, prolong mouse survival by 31.5 to 46.0% (P < 0.0001), and improve their overall physical condition. Therefore, our work demonstrates that low-frequency rotating magnetic fields not only can be used as a research tool to perturb F-actin but also can inhibit breast cancer metastasis through F-actin modulation while having minimum effects on normal cells, which reveals their potential to be developed as temporal-controlled, noninvasive, and high-penetration physical treatments for metastatic cancer.
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Affiliation(s)
- Xinmiao Ji
- High Magnetic Field Laboratory of CAS (CHMFL), CAS Key Laboratory of High Magnetic Field and Ion Beam Physical Biology,
HFIPS, Hefei, Anhui 230031, P.R China
| | - Xiaofei Tian
- Institutes of Physical Science and Information Technology,
Anhui University, Hefei, Anhui, 230601, P. R. China
| | - Shuang Feng
- High Magnetic Field Laboratory of CAS (CHMFL), CAS Key Laboratory of High Magnetic Field and Ion Beam Physical Biology,
HFIPS, Hefei, Anhui 230031, P.R China
| | - Lei Zhang
- High Magnetic Field Laboratory of CAS (CHMFL), CAS Key Laboratory of High Magnetic Field and Ion Beam Physical Biology,
HFIPS, Hefei, Anhui 230031, P.R China
| | - Junjun Wang
- High Magnetic Field Laboratory of CAS (CHMFL), CAS Key Laboratory of High Magnetic Field and Ion Beam Physical Biology,
HFIPS, Hefei, Anhui 230031, P.R China
| | - Ruowen Guo
- High Magnetic Field Laboratory of CAS (CHMFL), CAS Key Laboratory of High Magnetic Field and Ion Beam Physical Biology,
HFIPS, Hefei, Anhui 230031, P.R China
- Science Island Branch of Graduate School,
University of Science and Technology of China, Hefei, Anhui 230031, P.R China
| | - Yiming Zhu
- High Magnetic Field Laboratory of CAS (CHMFL), CAS Key Laboratory of High Magnetic Field and Ion Beam Physical Biology,
HFIPS, Hefei, Anhui 230031, P.R China
- Science Island Branch of Graduate School,
University of Science and Technology of China, Hefei, Anhui 230031, P.R China
| | - Xin Yu
- High Magnetic Field Laboratory of CAS (CHMFL), CAS Key Laboratory of High Magnetic Field and Ion Beam Physical Biology,
HFIPS, Hefei, Anhui 230031, P.R China
- Science Island Branch of Graduate School,
University of Science and Technology of China, Hefei, Anhui 230031, P.R China
| | - Yongsen Zhang
- High Magnetic Field Laboratory of CAS (CHMFL), CAS Key Laboratory of High Magnetic Field and Ion Beam Physical Biology,
HFIPS, Hefei, Anhui 230031, P.R China
| | - Haifeng Du
- High Magnetic Field Laboratory of CAS (CHMFL), CAS Key Laboratory of High Magnetic Field and Ion Beam Physical Biology,
HFIPS, Hefei, Anhui 230031, P.R China
| | - Vitalii Zablotskii
- Institute of Physics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Xin Zhang
- High Magnetic Field Laboratory of CAS (CHMFL), CAS Key Laboratory of High Magnetic Field and Ion Beam Physical Biology,
HFIPS, Hefei, Anhui 230031, P.R China
- Institutes of Physical Science and Information Technology,
Anhui University, Hefei, Anhui, 230601, P. R. China
- Science Island Branch of Graduate School,
University of Science and Technology of China, Hefei, Anhui 230031, P.R China
- International Magnetobiology Frontier Research Center, Science Island, Hefei 230031, P.R. China
- Address correspondence to:
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Ge S, Li J, Huang D, Cai Y, Fang J, Jiang H, Hu B. Strong static magnetic field delayed the early development of zebrafish. Open Biol 2019; 9:190137. [PMID: 31662097 PMCID: PMC6833226 DOI: 10.1098/rsob.190137] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
One of the major topics in magnetobiology is the biological effects of strong static magnetic field (SMF) on living organisms. However, there has been a paucity of the comprehensive study of the long-term effects of strong SMF on an animal's development. Here, we explored this question with zebrafish, an excellent model organism for developmental study. In our research, zebrafish eggs, just after fertilization, were exposed to a 9.0 T SMF for 24 h, the critical period of post-fertilization development from cleavage to segmentation. The effects of strong SMF exposure on the following developmental progress of zebrafish were studied until 6 days post-fertilization (dpf). Results showed that 9.0 T SMF exposure did not influence the survival or the general developmental scenario of zebrafish embryos. However, it slowed down the developmental pace of the whole animal, and the late developers would catch up with their control peers after the SMF was removed. We proposed a mechanical model and deduced that the development delaying effect was caused by the interference of SMF in microtubule and spindle positioning during mitosis, especially in early cleavages. Our research data provide insights into how strong SMF influences the developing organisms through basic physical interactions with intracellular macromolecules.
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Affiliation(s)
- Shuchao Ge
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
| | - Jingchen Li
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Hefei National Laboratory for Physical Science at the Microscale, Department of Modern Mechanics, CAS Center for Excellence in Complex System Mechanics, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
| | - Dengfeng Huang
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
| | - Yuan Cai
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
| | - Jun Fang
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of the Chinese Academy of Science, Hefei, Anhui 230031, People's Republic of China
| | - Hongyuan Jiang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Hefei National Laboratory for Physical Science at the Microscale, Department of Modern Mechanics, CAS Center for Excellence in Complex System Mechanics, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
| | - Bing Hu
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
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Zhang L, Hou Y, Li Z, Ji X, Wang Z, Wang H, Tian X, Yu F, Yang Z, Pi L, Mitchison TJ, Lu Q, Zhang X. 27 T ultra-high static magnetic field changes orientation and morphology of mitotic spindles in human cells. eLife 2017; 6. [PMID: 28244368 PMCID: PMC5370190 DOI: 10.7554/elife.22911] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 02/26/2017] [Indexed: 12/12/2022] Open
Abstract
Purified microtubules have been shown to align along the static magnetic field (SMF) in vitro because of their diamagnetic anisotropy. However, whether mitotic spindle in mammalian cells can be aligned by magnetic field has not been experimentally proved. In particular, the biological effects of SMF of above 20 T (Tesla) on mammalian cells have never been reported. Here we found that in both CNE-2Z and RPE1 human cells spindle orients in 27 T SMF. The direction of spindle alignment depended on the extent to which chromosomes were aligned to form a planar metaphase plate. Our results show that the magnetic torque acts on both microtubules and chromosomes, and the preferred direction of spindle alignment relative to the field depends more on chromosome alignment than microtubules. In addition, spindle morphology was also perturbed by 27 T SMF. This is the first reported study that investigated the mammalian cellular responses to ultra-high magnetic field of above 20 T. Our study not only found that ultra-high magnetic field can change the orientation and morphology of mitotic spindles, but also provided a tool to probe the role of spindle orientation and perturbation in developmental and cancer biology. DOI:http://dx.doi.org/10.7554/eLife.22911.001 Nowadays, a number of methods can be used to ‘look’ inside the body to investigate potential health problems. One of these is a technique called magnetic resonance imaging (MRI) that uses magnetic fields that are several hundred times stronger than a fridge magnet (or over 10,000 times stronger than the Earth’s natural magnetic field) to generate images of the inside of the body. In general, stronger magnetic fields enable higher quality images to be obtained. However, the effects of exposing the body’s cells to these magnetic fields have not been fully determined. Like most other biological materials, protein polymers called microtubules can respond to high magnetic fields – for example, by aligning with the field. Microtubules play a number of roles inside cells. This includes forming the mitotic spindle that separates copies of chromosomes – the structures in which the majority of a cell’s genetic material is stored – equally between dividing cells. The orientation of the mitotic spindle determines the direction in which a cell will divide. This direction is important for generating different types of cells and tissues. Furthermore, many cancerous cells have incorrectly oriented spindles. Zhang, Hou et al. have now exposed cancerous and normal human cells to magnetic fields of varying strengths. The maximum magnetic field strength tested (27 Tesla – or around 10 times the highest field strengths produced by standard hospital MRI scanners) did not kill the cells after four hours of exposure, but the orientation of the spindles inside the cells did change. In addition, the 27 Tesla magnetic field caused spindles that were perpendicular to the direction of the field to widen. At an intermediate field strength (9 Tesla – a magnetic field strength that has been used in some experimental MRI scanners), the orientation of the spindle only changed after three days of continuous exposure to the magnetic field. Lower field strengths (such as those currently used in hospital MRI scanners) did not alter the orientation of the spindle even after seven days of exposure. Zhang, Hou et al. also observed that the magnetic field acts on both the microtubules and chromosomes. However, the alignment of the chromosomes in the cell was the greatest determinant of the direction in which the spindle would align itself in response to the magnetic field. The next step is to analyze the consequences of magnetic field-induced spindle orientation changes – can these lead to cancer or reduce cancer growth, or change how animal tissues develop? Understanding how to control the position of the spindle could also ultimately make it possible to use ultra-high magnetic fields to engineer tissues or stimulate their regeneration. DOI:http://dx.doi.org/10.7554/eLife.22911.002
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Affiliation(s)
- Lei Zhang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China.,University of Science and Technology of China, Hefei, China
| | - Yubin Hou
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China
| | - Zhiyuan Li
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China
| | - Xinmiao Ji
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China
| | - Ze Wang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China.,University of Science and Technology of China, Hefei, China
| | - Huizhen Wang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China.,University of Science and Technology of China, Hefei, China
| | - Xiaofei Tian
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China.,University of Science and Technology of China, Hefei, China
| | - Fazhi Yu
- University of Science and Technology of China, Hefei, China
| | - Zhenye Yang
- University of Science and Technology of China, Hefei, China
| | - Li Pi
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China.,University of Science and Technology of China, Hefei, China
| | - Timothy J Mitchison
- Department of Systems Biology, Harvard Medical School, Boston, United States
| | - Qingyou Lu
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China.,University of Science and Technology of China, Hefei, China.,Collaborative Innovation Center of Advanced Microstructure, Nanjing University, Nanjing, China
| | - Xin Zhang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China
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Abstract
SummaryThe order Caudata includes about 660 species and displays a variety of important developmental traits such as cleavage pattern and egg size. However, the cleavage process of tailed amphibians has never been analyzed within a phylogenetic framework. We use published data on the embryos of 36 species concerning the character of the third cleavage furrow (latitudinal, longitudinal or variable) and the magnitude of synchronous cleavage period (up to 3–4 synchronous cell divisions in the animal hemisphere or a considerably longer series of synchronous divisions followed by midblastula transition). Several species from basal caudate families Cryptobranchidae (Andrias davidianus and Cryptobranchus alleganiensis) and Hynobiidae (Onychodactylus japonicus) as well as several representatives from derived families Plethodontidae (Desmognathus fuscus and Ensatina eschscholtzii) and Proteidae (Necturus maculosus) are characterized by longitudinal furrows of the third cleavage and the loss of synchrony as early as the 8-cell stage. By contrast, many representatives of derived families Ambystomatidae and Salamandridae have latitudinal furrows of the third cleavage and extensive period of synchronous divisions. Our analysis of these ontogenetic characters mapped onto a phylogenetic tree shows that the cleavage pattern of large, yolky eggs with short series of synchronous divisions is an ancestral trait for the tailed amphibians, while the data on the orientation of third cleavage furrows seem to be ambiguous with respect to phylogeny. Nevertheless, the midblastula transition, which is characteristic of the model species Ambystoma mexicanum (Caudata) and Xenopus laevis (Anura), might have evolved convergently in these two amphibian orders.
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Mo WC, Liu Y, Cooper HM, He RQ. Altered development of Xenopus embryos in a hypogeomagnetic field. Bioelectromagnetics 2011; 33:238-46. [PMID: 21853450 DOI: 10.1002/bem.20699] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Accepted: 07/22/2011] [Indexed: 11/06/2022]
Abstract
The hypogeomagnetic field (HGMF; magnetic fields <200 nT) is one of the fundamental environmental factors of space. However, the effect of HGMF exposure on living systems remains unclear. In this article, we examine the biological effects of HGMF on the embryonic development of Xenopus laevis (African clawed frog). A decrease in horizontal third cleavage furrows and abnormal morphogenesis were observed in Xenopus embryos growing in the HGMF. HGMF exposure at the two-cell stage, but no later than the four-cell stage, is enough to alter the third cleavage geometry pattern. Immunofluorescent staining for α-tubulin showed reorientation of the spindle of four-cell stage blastomeres. These results indicate that a brief (2-h) exposure to HGMF is sufficient to interfere with the development of Xenopus embryos at cleavage stages. Also, the mitotic spindle could be an early sensor to the deprivation of the geomagnetic field, which provides a clue to the molecular mechanism underlying the morphological and other changes observed in the developing and/or developed embryos.
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Affiliation(s)
- Wei-Chuan Mo
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing, China
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Hammer BE, Kidder LS, Williams PC, Xu WW. Magnetic Levitation of MC3T3 Osteoblast Cells as a Ground-Based Simulation of Microgravity. MICROGRAVITY SCIENCE AND TECHNOLOGY 2009; 21:311-318. [PMID: 20052306 PMCID: PMC2801443 DOI: 10.1007/s12217-008-9092-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Diamagnetic samples placed in a strong magnetic field and a magnetic field gradient experience a magnetic force. Stable magnetic levitation occurs when the magnetic force exactly counter balances the gravitational force. Under this condition, a diamagnetic sample is in a simulated microgravity environment. The purpose of this study is to explore if MC3T3-E1 osteoblastic cells can be grown in magnetically simulated hypo-g and hyper-g environments and determine if gene expression is differentially expressed under these conditions. The murine calvarial osteoblastic cell line, MC3T3-E1, grown on Cytodex-3 beads, were subjected to a net gravitational force of 0, 1 and 2 g in a 17 T superconducting magnet for 2 days. Microarray analysis of these cells indicated that gravitational stress leads to up and down regulation of hundreds of genes. The methodology of sustaining long-term magnetic levitation of biological systems are discussed.
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Affiliation(s)
- Bruce E. Hammer
- Department of Radiology, University of Minnesota, 420 Delaware St., MMC 292, Minneapolis, MN 55455, USA, URL: www.ciamr.umn.edu
| | - Louis S. Kidder
- Department of Radiology, University of Minnesota, 420 Delaware St., MMC 292, Minneapolis, MN 55455, USA, URL: www.ciamr.umn.edu
| | - Philip C. Williams
- Department of Radiology, University of Minnesota, 420 Delaware St., MMC 292, Minneapolis, MN 55455, USA, URL: www.ciamr.umn.edu
| | - Wayne Wenzhong Xu
- Supercomputing Institute for Advanced Computational Research, University of Minnesota, 117 Pleasant St., Minneapolis, MN 55455, USA
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Lee SC, Mietchen D, Cho JH, Kim YS, Kim C, Hong KS, Lee C, Kang D, Lee W, Cheong C. In vivo magnetic resonance microscopy of differentiation in Xenopus laevis embryos from the first cleavage onwards. Differentiation 2007; 75:84-92. [PMID: 17244024 DOI: 10.1111/j.1432-0436.2006.00114.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Differentiation inside a developing embryo can be observed by a variety of optical methods but hardly so in opaque organisms. Embryos of the frog Xenopus laevis--a popular model system--belong to the latter category and, for this reason, are predominantly being investigated by means of physical sectioning. Magnetic resonance imaging (MRI) is a noninvasive method independent of the optical opaqueness of the object. Starting out from clinical diagnostics, the technique has now developed into a branch of microscopy--MR microscopy--that provides spatial resolutions of tens of microns for small biological objects. Nondestructive three-dimensional images of various embryos have been obtained using this technique. They were, however, usually acquired by long scans of fixed embryos. Previously reported in vivo studies did not cover the very early embryonic stages, mainly for sensitivity reasons. Here, by applying high field MR microscopy to the X. laevis system, we achieved the temporal and spatial resolution required for observing subcellular dynamics during early cell divisions in vivo. We present image series of dividing cells and nuclei and of the whole embryonic development from the zygote onto the hatching of the tadpole. Additionally, biomechanical analyses from successive MR images are introduced. These results demonstrate that MR microscopy can provide unique contributions to investigations of differentiating cells and tissues in vivo.
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Affiliation(s)
- Seung-Cheol Lee
- Frontier Research Laboratory, Korea Basic Science Institute, 804-1 Yangcheong, Ochang, Cheongwon, Chungbuk 363-883, Korea
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Eguchi Y, Ueno S, Kaito C, Sekimizu K, Shiokawa K. Cleavage and survival of Xenopus embryos exposed to 8 T static magnetic fields in a rotating clinostat. Bioelectromagnetics 2006; 27:307-13. [PMID: 16557503 DOI: 10.1002/bem.20215] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In this study, we examined cleavage and survival of fertilized Xenopus embryos exposed to 8 T static magnetic fields (SMFs). We investigated fertilized Xenopus embryos exposed to magnetic field either in static chamber or in a rotating culture system. Our results showed that the exposure to the strong magnetic field of 8 T changed the third cleavage furrow from the usual horizontal one to a perpendicular one; however, when the direction of gravity was randomized by exposing embryos to magnetic field in a rotating culture system, the third cleavage furrow were formed horizontally, a finding which suggests that the observed distortion of the third cleavage furrow in magnetism-exposed embryos was accomplished by altering gravity effects which were elicited by diamagnetic force due to high gradient magnetic field. Our results also showed that the exposure to the strong magnetic field did not damage survival. These results demonstrate that SMF and altering gravity cause distortion of the third cleavage furrow and show that effects of exposing cleavage embryos to magnetic field were transient and did not affect the post-cleavage development. We also showed that strong magnetic field is not hazardous to the cleavage and blastula-gastrula transition of developing embryonic cells.
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Affiliation(s)
- Yawara Eguchi
- Department of Biomedical Engineering, Graduate School of Medicine, University of Tokyo, Japan.
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Schenck JF. Physical interactions of static magnetic fields with living tissues. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2005; 87:185-204. [PMID: 15556658 DOI: 10.1016/j.pbiomolbio.2004.08.009] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Clinical magnetic resonance imaging (MRI) was introduced in the early 1980s and has become a widely accepted and heavily utilized medical technology. This technique requires that the patients being studied be exposed to an intense magnetic field of a strength not previously encountered on a wide scale by humans. Nonetheless, the technique has proved to be very safe and the vast majority of the scans have been performed without any evidence of injury to the patient. In this article the history of proposed interactions of magnetic fields with human tissues is briefly reviewed and the predictions of electromagnetic theory on the nature and strength of these interactions are described. The physical basis of the relative weakness of these interactions is attributed to the very low magnetic susceptibility of human tissues and the lack of any substantial amount of ferromagnetic material normally occurring in these tissues. The presence of ferromagnetic foreign bodies within patients, or in the vicinity of the scanner, represents a very great hazard that must be scrupulously avoided. As technology and experience advance, ever stronger magnetic field strengths are being brought into service to improve the capabilities of this imaging technology and the benefits to patients. It is imperative that vigilance be maintained as these higher field strengths are introduced into clinical practice to assure that the high degree of patient safety that has been associated with MRI is maintained.
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Affiliation(s)
- John F Schenck
- General Electric Global Research Center, Building K1/NMR, 1 Research Drive, Schenectady, NY 13209, USA.
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Abstract
Recent experiments have shown that intense static magnetic fields can alter the geometry of the early cell cleavages of Xenopus laevis eggs. The changes depend on field orientation, strength, and timing. We present a model that qualitatively accounts for these effects and which presumes that the structures involved in cell division are cylindrically symmetric and diamagnetically anisotropic and that the geometry of the centrosome replication and spreading processes dictates the nominal cleavage geometry. Within this model, the altered cleavage geometry results from the magnetic field-induced realignment of mitotic structures, which causes a realignment of the centrosome replication and spreading processes.
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Affiliation(s)
- James M Valles
- Department of Physics, Brown University, Providence, Rhode Island 02912, USA.
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