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Seo J, Lee BK, Jin SU, Jang KE, Park JW, Kim YT, Park SJ, Jeong KS, Park J, Kim A, Kim Y, Chang Y. Altered executive function in the lead-exposed brain: A functional magnetic resonance imaging study. Neurotoxicology 2015; 50:1-9. [DOI: 10.1016/j.neuro.2015.07.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 07/08/2015] [Accepted: 07/08/2015] [Indexed: 10/23/2022]
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Seo J, Lee BK, Jin SU, Park JW, Kim YT, Ryeom HK, Lee J, Suh KJ, Kim SH, Park SJ, Jeong KS, Ham JO, Kim Y, Chang Y. Lead-induced impairments in the neural processes related to working memory function. PLoS One 2014; 9:e105308. [PMID: 25141213 PMCID: PMC4139362 DOI: 10.1371/journal.pone.0105308] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 07/22/2014] [Indexed: 11/18/2022] Open
Abstract
Background It is well known that lead exposure induces neurotoxic effects, which can result in a variety of neurocognitive dysfunction. Especially, occupational lead exposures in adults are associated with decreases in cognitive performance including working memory. Despite recent advances in human neuroimaging techniques, the neural correlates of lead-exposed cognitive impairment remain unclear. Therefore, this study was aimed to compare the neural activations in relation to working memory function between the lead-exposed subjects and healthy controls. Methodology/Principal Findings Thirty-one lead-exposed subjects and 34 healthy subjects performed an n-back memory task during MRI scan. We performed fMRI using the 1-back and 2-back memory tasks differing in cognitive demand. Functional MRI data were analyzed using within- and between-group analysis. We found that the lead-exposed subjects showed poorer working memory performance during high memory loading task than the healthy subjects. In addition, between-group analyses revealed that the lead-exposed subjects showed reduced activation in the dorsolateral prefrontal cortex, ventrolateral prefrontal cortex, pre supplementary motor areas, and inferior parietal cortex. Conclusions/Significance Our findings suggest that functional abnormalities in the frontoparietal working memory network might contribute to impairments in maintenance and manipulation of working memory in the lead-exposed subjects.
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Affiliation(s)
- Jeehye Seo
- Department of Medical & Biological Engineering, Kyungpook National University, Dong-In dong, Jung-gu, Daegu, Korea
| | | | - Seong-Uk Jin
- Department of Medical & Biological Engineering, Kyungpook National University, Dong-In dong, Jung-gu, Daegu, Korea
| | - Jang Woo Park
- Department of Medical & Biological Engineering, Kyungpook National University, Dong-In dong, Jung-gu, Daegu, Korea
| | - Yang-Tae Kim
- Department of Psychiatry, School of Medicine, Keimyung University, Daegu, Korea
| | - Hun-Kyu Ryeom
- Department of Radiology, Kyungpook National University College of Medicine, Dong-In dong, Jung-gu, Daegu, Korea
| | - Jongmin Lee
- Department of Radiology, Kyungpook National University College of Medicine, Dong-In dong, Jung-gu, Daegu, Korea
| | - Kyung Jin Suh
- Department of Radiology, College of Medicine, Dongguk University, Gyeongju, Korea
| | - Suk Hwan Kim
- Department of Occupational and Environmental Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea
| | - Sin-Jae Park
- Department of Psychiatry, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea
| | - Kyoung Sook Jeong
- Department of Occupational and Environmental Medicine, Dongguk University College of Medicine, Dongguk University Ilsan Hospital, Goyang, Korea
| | - Jung-O Ham
- Department of Occupational and Environmental Medicine, Soonchunhyan University Hospital, Cheonan, Korea
| | - Yangho Kim
- Department of Occupational and Environmental Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea
- * E-mail: (YC); (YK)
| | - Yongmin Chang
- Department of Medical & Biological Engineering, Kyungpook National University, Dong-In dong, Jung-gu, Daegu, Korea
- Department of Radiology, Kyungpook National University College of Medicine, Dong-In dong, Jung-gu, Daegu, Korea
- Department of Molecular Medicine, Kyungpook National University College of Medicine, Dong-In dong, Jung-gu, Daegu, Korea
- * E-mail: (YC); (YK)
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Jung DJ, Han M, Jin SU, Lee SH, Park I, Cho HJ, Kwon TJ, Lee HJ, Cho JH, Lee KY, Chang Y. Functional mapping of the auditory tract in rodent tinnitus model using manganese-enhanced magnetic resonance imaging. Neuroimage 2014; 100:642-9. [PMID: 24983712 DOI: 10.1016/j.neuroimage.2014.06.055] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 06/20/2014] [Accepted: 06/23/2014] [Indexed: 10/25/2022] Open
Abstract
Animal models of salicylate-induced tinnitus have demonstrated that salicylate modulates neuronal activity in several brain structures leading to neuronal hyperactivity in auditory and non-auditory brain areas. In addition, these animal tinnitus models indicate that tinnitus can be a perceptual consequence of altered spontaneous neural activity along the auditory pathway. Peripheral and/or central effects of salicylate can account for neuronal activity changes in salicylate-induced tinnitus. Because of this ambiguity, an in vivo imaging study would be able to address the peripheral and/or central involvement of salicylate-induced tinnitus. Therefore, in the present study, we developed a novel manganese-enhanced magnetic resonance imaging (MEMRI) method to map the in vivo functional auditory tract in a salicylate-induced tinnitus animal model by administrating manganese through the round window. We found that acute salicylate-induced tinnitus resulted in higher manganese uptake in the cochlea and in the central auditory structures. Furthermore, serial MRI scans demonstrated that the manganese signal increased in an anterograde fashion from the cochlea to the cochlear nucleus. Therefore, our in vivo MEMRI data suggest that acute salicylate-induced tinnitus is associated with higher spontaneous neural activity both in peripheral and central auditory pathways.
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Affiliation(s)
- Da Jung Jung
- Department of Otorhinolaryngology-Head and Neck Surgery, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Mun Han
- Department of Medical and Biological Engineering, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Seong-Uk Jin
- Department of Medical and Biological Engineering, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Sang Heun Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Daegu Veterans Hospital, Daegu, Republic of Korea
| | - Ilyong Park
- Department of Biomedical Engineering, College of Medicine, Dankook University, Cheonan, Republic of Korea
| | - Hyun-Ju Cho
- Department of Biology, College of Natural Science, Kyungpook National University, Daegu, Republic of Korea
| | - Tae-Jun Kwon
- Department of Biology, College of Natural Science, Kyungpook National University, Daegu, Republic of Korea
| | - Hui Joong Lee
- Department of Radiology, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Jin Ho Cho
- Department of Electronic Engineering, College of IT Engineering, Kyungpook National University, Daegu, Republic of Korea
| | - Kyu-Yup Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea.
| | - Yongmin Chang
- Department of Medical and Biological Engineering, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea; Department of Radiology, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea; Department of Molecular Medicine, BK21 Plus KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu, Republic of Korea.
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Chang Y, Jin SU, Kim Y, Shin KM, Lee HJ, Kim SH, Ahn JH, Park SJ, Jeong KS, Weon YC, Lee H. Decreased brain volumes in manganese-exposed welders. Neurotoxicology 2013; 37:182-9. [PMID: 23685157 DOI: 10.1016/j.neuro.2013.05.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 04/26/2013] [Accepted: 05/04/2013] [Indexed: 01/09/2023]
Abstract
BACKGROUND A great deal of research has been devoted to identifying subclinical functional brain abnormalities in manganese (Mn)-exposed welders. However, no previous study has investigated morphological brain abnormalities, such as changes in brain volume, in welders. This study evaluates morphological changes in brain volume among welders, and investigates the relationship between structural brain abnormalities and subclinical dysfunction in this population. METHODS We used voxel-based morphometry (VBM) to assess differences in gray and white matter brain volumes between 40 welders with chronic Mn exposure and 26 age-matched control subjects. Correlation analyses were used to investigate the relationship between brain volume changes and decreased performance on neurobehavioral tests. RESULTS Brain volumes in the globus pallidus and cerebellar regions were significantly diminished in welders with chronic Mn exposure compared to controls (FDR-corrected P<0.05). These changes in brain volume were negatively correlated with cognitive performance and grooved pegboard scores. CONCLUSION There are measurable brain volume reductions in the globus pallidus and cerebellum of welders chronically exposed to Mn, and these volume reductions correlate with cognitive and motor neurobehavioral deficits. Our findings therefore indicate that volumetric measurement could be a useful subclinical marker among welders that show no signs of manganism.
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Affiliation(s)
- Yongmin Chang
- Department of Molecular Medicine, Kyungpook National University College of Medicine, Kyungpook National University Hospital, Daegu, South Korea
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Jin SU, Lee JJ, Hong KS, Han M, Park JW, Lee HJ, Lee S, Lee KY, Shin KM, Cho JH, Cheong C, Chang Y. Intratympanic manganese administration revealed sound intensity and frequency dependent functional activity in rat auditory pathway. Magn Reson Imaging 2013; 31:1143-9. [PMID: 23659767 DOI: 10.1016/j.mri.2013.03.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 01/24/2013] [Accepted: 03/08/2013] [Indexed: 11/28/2022]
Abstract
The cochlear plays a vital role in the sense and sensitivity of hearing; however, there is currently a lack of knowledge regarding the relationships between mechanical transduction of sound at different intensities and frequencies in the cochlear and the neurochemical processes that lead to neuronal responses in the central auditory system. In the current study, we introduced manganese-enhanced MRI (MEMRI), a convenient in vivo imaging method, for investigation of how sound, at different intensities and frequencies, is propagated from the cochlear to the central auditory system. Using MEMRI with intratympanic administration, we demonstrated differential manganese signal enhancements according to sound intensity and frequencies in the ascending auditory pathway of the rat after administration of intratympanic MnCl2.Compared to signal enhancement without explicit sound stimuli, auditory structures in the ascending auditory pathway showed stronger signal enhancement in rats who received sound stimuli of 10 and 40 kHz. In addition, signal enhancement with a stimulation frequency of 40 kHz was stronger than that with 10 kHz. Therefore, the results of this study seem to suggest that, in order to achieve an effective response to high sound intensity or frequency, more firing of auditory neurons, or firing of many auditory neurons together for the pooled neural activity is needed.
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Affiliation(s)
- Seong-Uk Jin
- Department of Medical & Biological Engineering, Kyungpook National University, Dongduk-Ro, Jung-Gu, Daegu, Korea
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Ahmad T, Bae H, Rhee I, Chang Y, Jin SU, Hong S. Gold-coated iron oxide nanoparticles as a T2 contrast agent in magnetic resonance imaging. J Nanosci Nanotechnol 2012; 12:5132-5137. [PMID: 22966533 DOI: 10.1166/jnn.2012.6368] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Gold-coated iron oxide (Fe3O4) nanoparticles were synthesized for use as a T2 contrast agent in magnetic resonance imaging (MRI). The coated nanoparticles were spherical in shape with an average diameter of 20 nm. The gold shell was about 2 nm thick. The bonding status of the gold on the nanoparticle surfaces was checked using a Fourier transform infrared spectrometer (FTIR). The FTIR spectra confirmed the attachment of homocysteine, in the form of thiolates, to the Au shell of the Au-Fe3O4 nanoparticles. The relaxivity ratio, R2/R1, for the coated nanoparticles was 3-fold higher than that of a commercial contrast agent, Resovist, which showed the potential for their use as a T2 contrast agent with high efficacy. In animal experiments, the presence of the nanoparticles in rat liver resulted in a 71% decrease in signal intensity in T2-weighted MR images, indicating that our gold-coated iron oxide nanoparticles are suitable for use as a T2 contrast agent in MRI.
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Affiliation(s)
- Tanveer Ahmad
- Department of Physics, Kyungpook National University, Daegu, 702-701, Korea
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Bae H, Ahmad T, Rhee I, Chang Y, Jin SU, Hong S. Carbon-coated iron oxide nanoparticles as contrast agents in magnetic resonance imaging. Nanoscale Res Lett 2012; 7:44. [PMID: 22221912 PMCID: PMC3398329 DOI: 10.1186/1556-276x-7-44] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 01/05/2012] [Indexed: 05/19/2023]
Abstract
Coprecipitated ferrite nanoparticles were coated with carbon using a hydrothermal method. From transmission electron microscope pictures, we could see that the coated iron oxide nanoparticles were spherical in shape with an average diameter of 90 nm. The strong bonding of carbon on the nanoparticle surfaces was checked by noting the C = O and C = C vibrations in Fourier transform infrared spectra. The spin-lattice relaxation process [T1] and spin-spin relaxation process [T2] relaxivities of hydrogen protons in the aqueous solution of coated nanoparticles were determined to be 1.139 (mM·s)-1 and 1.115 (mM·s)-1, respectively. These results showed that the carbon-coated iron oxide nanoparticles are applicable as both T1 and T2 contrast agents in magnetic resonance imaging.PACS: 81.05.y; 76.60.Es; 61.46; 75.50.k; 87.61.
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Affiliation(s)
- Hongsub Bae
- Department of Physics, Kyungpook National University, Daegu, 702-701, Republic of Korea
| | - Tanveer Ahmad
- Department of Physics, Kyungpook National University, Daegu, 702-701, Republic of Korea
| | - Ilsu Rhee
- Department of Physics, Kyungpook National University, Daegu, 702-701, Republic of Korea
| | - Yongmin Chang
- Department of Molecular Medicine and Diagnostic Radiology, Kyungpook University Hospital, Daegu, 700-422, Republic of Korea
| | - Seong-Uk Jin
- Department of Molecular Medicine and Diagnostic Radiology, Kyungpook University Hospital, Daegu, 700-422, Republic of Korea
| | - Sungwook Hong
- Division of Science Education, Daegu University, Gyeongsan, 712-714, Republic of Korea
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Bae JE, Huh MI, Ryu BK, Do JY, Jin SU, Moon MJ, Jung JC, Chang Y, Kim E, Chi SG, Lee GH, Chae KS. The effect of static magnetic fields on the aggregation and cytotoxicity of magnetic nanoparticles. Biomaterials 2011; 32:9401-14. [DOI: 10.1016/j.biomaterials.2011.08.075] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 08/24/2011] [Indexed: 11/28/2022]
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