• YAKHAK HOEJI
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• v.31 no.5
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• pp.266-272
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• 1987

It is reasonably well known that there is a relationship between myelin formation and methylation of myelin basic protein in nerve cells. One of the suggestions is that arginine methylation of myelin basic protein could be of aid in the conjugation of myelin protein with the nonpolar lipid to form myelin. Abnormality in methylation of myclin basic protein might induce the neurological diseases in experimental animals as well as in human being. In the biological system, the methylation reaction is catalyzed by protein methaylse I using S-adenosyl-L-methionine as methyl donor. In this study, we examined the changes of S-adenosyl-L-methionine concentration and protein methylase I activity in developing rat brain tissues. The results are sumraerized as followings: (1) In brain tissues of fetus rat, the concentration of S-adenosyl-L-methionine was gradually decreased until to birth. However, the concentration in brain tissues of infant rat was suddenly increased at 7th day(just before myelination occur) birth. (2) Protein methylase I activity was decreased until to birth in brain of fetus rat and increased temporally just after birth, However, the enzyme activity showed no changes around 7th day after birth.

• Investigative Magnetic Resonance Imaging
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• v.25 no.2
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• pp.76-80
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• 2021

Post-concussion syndrome (PCS) following mild traumatic brain injury (mTBI) is a major factor that contributes to the increased socioeconomic burden caused by TBI. Myelin loss has been implicated in the development of PCS following mTBI. Diffusion tensor imaging (DTI), a traditional imaging modality for the evaluation of axonal and myelin integrity in mTBI, has intrinsic limitations, including its lack of specificity and its time-consuming and labor-intensive post-processing analysis. More recently, various fast MR techniques based on multicomponent relaxometry (MCR), including QRAPMASTER, mcDESPOT, and MDME sequences, have been developed. These MCR-based sequences can provide myelin water fraction/myelin volume fraction, a quantitative parameter more specific to myelin, which might serve as a surrogate marker of myelin volume, in a clinically feasible time. In this review, we summarize the clinical application of the MCR-based fast MR techniques in mTBI patients.

• Journal of Korean Neurosurgical Society
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• v.55 no.5
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• pp.244-247
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• 2014

Objective : The aim of this study was to evaluate the microanatomy and histological features of the central myelin in the root exit zone of facial nerve. Methods : Forty facial nerves with brain stem were obtained from 20 formalin fixed cadavers. Among them 17 facial nerves were ruined during preparation and 23 root entry zone (REZ) of facial nerves could be examined. The length of medial REZ, from detach point of facial nerve at the brain stem to transitional area, and the thickness of glial membrane of central myelin was measured. We cut brain stem along the facial nerve and made a tissue block of facial nerve REZ. Each tissue block was embedded with paraffin and serially sectioned. Slices were stained with hematoxylin and eosin (H&E), periodic acid-Schiff, and glial fibrillary acid protein. Microscopy was used to measure the extent of central myelin and thickness of outer glial membrane of central myelin. Thickness of glial membrane was examined at two different points, the thickest area of proximal and distal REZ. Results : Special stain with PAS and GFAP could be differentiated the central and peripheral myelin of facial nerve. The length of medial REZ was mean 2.6 mm (1.6-3.5 mm). The glial limiting membrane of brain stem is continued to the end of central myelin. We called it glial sheath of REZ. The thickness of glial sheath was mean $66.5{\mu}m(40-110{\mu}m$) at proximal REZ and $7.4{\mu}m(5-10{\mu}m$) at distal REZ. Conclusion : Medial REZ of facial nerve is mean 2.6 mm in length and covered by glial sheath continued from glial limiting membrane of brain stem. Glial sheath of central myelin tends to become thin toward transitional zone.

• Journal of Ginseng Research
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• v.47 no.2
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• pp.319-328
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• 2023

Background: Demyelination has been observed in neurological disorders, motivating researchers to search for components for enhancing remyelination. Previously we found that Rb1, a major ginsenoside in Korean Red Ginseng (KRG), enhances myelin formation. However, it has not been studied whether Rb1 or KRG function in remyelination after demyelination in vivo. Methods: Mice were fed 0.2% cuprizone-containing chow for 5 weeks and returned to normal chow with daily oral injection of vehicle, KRG, or Rb1 for 3 weeks. Brain sections were stained with luxol fast blue (LFB) staining or immunohistochemistry. Primary oligodendrocyte or astrocyte cultures were subject to normal or stress condition with KRG or Rb1 treatment to measure gene expressions of myelin, endoplasmic reticulum (ER) stress, antioxidants and leukemia inhibitory factor (LIF). Results: Compared to the vehicle, KRG or Rb1 increased myelin levels at week 6.5 but not 8, when measured by the LFB⁺ or GST-pi⁺ area within the corpus callosum. The levels of oligodendrocyte precursor cells, astrocytes, and microglia were high at week 5, and reduced afterwards but not changed by KRG or Rb1. In primary oligodendrocyte cultures, KRG or Rb1 increased expression of myelin genes, ER stress markers, and antioxidants. Interestingly, under cuprizone treatment, elevated ER stress markers were counteracted by KRG or Rb1. Under rotenone treatment, reduced myelin gene expressions were recovered by Rb1. In primary astrocyte cultures, KRG or Rb1 decreased LIF expression. Conclusion: KRG and Rb1 may improve myelin regeneration during the remyelination phase in vivo, potentially by directly promoting myelin gene expression.

• Journal of Life Science
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• v.8 no.1
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• pp.109-117
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• 1998

The synthesis and methylation in vivo of myleline basic protein(MBP) during the mouse brain devlopment was found to be the highest in youngest brain and declined progressively in mature brains. The relative rate of protein synthesis and methylation was a maximal ration in the youngest brain, This high ratio was wdll correlated with the higher protein methylase I (PM I) activity in younger brains. The jimpy mouse is the most severely affected dysmyelinating mutant and is characterized by failure to incorporate MBP into myelin. sheath. The MBP-specific PM I activity in 15-, 18-, and 21-days old hemizygous jimpy mice(jp/y)brains decreased by 20, 50 and 75%, respectively. Myelin fraction with different degrees of compaction were isolated from bovine brain, the most compact myelin fraction exhibited higher methylaccepting activity than the less compact dense fractions.

• Investigative Magnetic Resonance Imaging
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• v.23 no.2
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• pp.148-156
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• 2019

Hyperglycemia-induced hemichorea (HGHC) is a rare but characteristic hyperkinetic movement disorder involving limbs on one side of the body. In a 75-year-old woman with a left-sided HGHC, conventional brain MR imaging showed very subtle T1-hyperintensity and unique gadolinium enhancement in the basal ganglia contralateral to movements. Multi-parametric MRI was acquired using pulse sequence with quantification of relaxation times and proton density by multi-echo acquisition. Myelin map was reconstructed based on new tissue classification modeling. In this case report of multi-parametric MRI, quantitative measurement of myelin change related to HGHC in brain structures and its possible explanations are presented. This is the first study to demonstrate myelin loss related to hyperglycemic insult in multi-parametric quantitative MR imaging.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.96-96
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• 1995

It was recognized that lead intoxication reduces thiamine content in the brain of rat and this change produces the alterations of thiamine-related biochemical reactions. In the present study, it was tested whether the changes of myelin composition as well as seizure threshold induced by lead intoxication in rats may be related to these changes of thiamine status and thiamine related biochemical factors. Wistar rats were divided into five groups: Control group, Lead-treated group, Lead plus Thiamine-treated group, Thiamine-deficient group, Pyrithiamine-treated group. Each group was divided into three subgroups: 3, 7 and 16 week old group. Myelin protein and phospholipid, one of the compositions of myelin lipid, were measured in the myelin isolated from rat brain. Threshold of electric shock seizure was tested in each group. The amount of each myelin composition in lead-treated group and thiamine-deficient group was significantly lower than those of all the brains in control group, but recovery by supplementation with thiamine during lead intoxication was occurred only in the cerebellum of 3 week old animal. Thresholds of the electric shock seizure of lead treated group and thiamine deficient group in 3 and 7 week old rats were significantly lower than those of control group, while those of lead plus thiamine treated group were similar to those of control group.

• Biomolecules & Therapeutics
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• v.25 no.3
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• pp.231-238
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• 2017

Myelin is a specialized structure of the nervous system that both enhances electrical conductance and insulates neurons from external risk factors. In the central nervous system, polarized oligodendrocytes form myelin by wrapping processes in a spiral pattern around neuronal axons through myelin-related gene regulation. Since these events occur at a distance from the cell body, post-transcriptional control of gene expression has strategic advantage to fine-tune the overall regulation of protein contents in situ. Therefore, many research interests have been focused to identify RNA binding proteins and their regulatory mechanism in myelinating compartments. Fragile X mental retardation protein (FMRP) is one such RNA binding protein, regulating its target expression by translational control. Although the majority of works on FMRP have been performed in neurons, it is also found in the developing or mature glial cells including oligodendrocytes, where its function is not well understood. Here, we will review evidences suggesting abnormal translational regulation of myelin proteins with accompanying white matter problem and neurological deficits in fragile X syndrome, which can have wider mechanistic and pathological implication in many other neurological and psychiatric disorders.

• BMB Reports
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• v.33 no.3
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• pp.276-278
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• 2000

The postsynaptic density (PSD), a large protein complex beneath the postsynaptic membrane, is notorious for its 'stickiness'. In order to understand the molecular composition of the PSD fraction, a 17 kDa protein band was isolated by electroelution from SDS-geis, and its partial amino acid sequence was determined from HPLC-purified tryptic peptides of the protein. Surprisingly, the amino acid sequence was identical to that of the previously reported 17 kDa isoform of the myelin basic protein (MBP), an essential protein in CNS myelin formation. Since the protein band represented ~2% of the total proteins in the 1 % n-octyl glucoside-insoluble PSD fraction, these results indicate that a significant amount of the 17 kDa isoform of MBP is tightly associated with the PSD during preparation of the PSD fraction.

• Journal of Nutrition and Health
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• v.40 no.2
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• pp.130-137
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• 2007

Myelin basic protein (MBP), a major structural protein of the myelin, is thought to be important for the maintenance of myelin in the central nervous system (CNS). We investigated the effect of maternal folic acid nutritional status on the folate level and the synthesis of MBP in the offspring. In order to test this hypothesis, female Sprague-Dawley rats were fed either folic acid sufficient (8 mg/kg diet) or deficient (0 mg/kg diet) diet from 2 wks prior to the mating throughout the entire pregnancy, lactation and weaning period. We examined plasma folate level by the radioimmunoassay and homocysteine level by HPLC, respectively. The MBP expression was measured by the western blot analysis. The maternal folic acid deficiency decreased plasma folate level with a concomitant increase in plasma homocysteine level in their offspring. The maternal folic acid deficiency decreased hepatic levels of SAM and SAM/SAH ratio with a concomitant increase in hepatic levels of SAH and the MBP expression of spinal cord in their offspring at 7 wks of age. These results suggest that maternal folic acid nutritional status affect plasma folate and homocysteine level in their offspring. Moreover, the maternal folic acid deficiency mi호t inhibit the MBP expression of the spinal cord and disrupt many other vital CNS reactions in their offspring.