• Archives of Pharmacal Research
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• v.29 no.4
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• pp.265-275
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• 2006

In the developing brain, capillaries are differentiated and matured into the blood-brain barrier (BBB), which is composed of cerebral endothelial cells, astrocyte end-feet, and pericytes. Since the BBB regulates the homeostasis of central nervous system (CNS), the maintenance of the BBB is important for CNS function. The disruption of the BBB may result in many brain disorders including brain tumors. However, the molecular mechanism of BBB formation and maintenance is poorly understood. Here, we summarize recent advances in the role of oxygen tension and growth factors on BBB development and maintenance, and in BBB dysfunction related with brain tumors.

• Korean Journal of Veterinary Research
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• v.41 no.3
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• pp.395-400
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• 2001

The present study analyze the morphological aspects of the cerebrum of mice with prenatal exposure to high and low dose (0.5, 1, 2 Gy) of $\gamma$-radiation on gestation day 12 or 16. The animal were allowed to give birth and the offspring were sacrificed at postnatal days 28 for gross and microscopic examination of cerebrum. Their body weight, brain weight, brain length, brain width, cortical thickness and area of cingulum bundle were examined. The histological and planimetric analysis were performed observing coronal sections. The gross malfomation (microcephaly) and abnormality of cortical architecture were prominent after exposure to 2 Gy on day 12 of gestation. significant dose-related reductions in body weight, brain weight, brain size were found in all irradiated groups. A significant change was found in thickness of the cerebral cortex and area of the cingulum bundle in the groups exposed to 0.5 Gy or more. There was no difference a lamina patter of six layers in cerebral cortex between the control and irradiated groups, but cell packing density increased significantly in the group exposed to 1 Gy or more. These results suggested that dose as low as 0.5 Gy could cause a morphologically reduce change in developing mouse cerebrum and exposure on day 12 of gestation to $\gamma$-irradiation is a particularly sensitive phase in causing malformation and abnormality of central nerve system.

• Journal of Nutrition and Health
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• v.17 no.3
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• pp.199-209
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• 1984

Pregnant rats were fed a pyridoxine deficient diet during the gestation and lactation. DEF I group received the deficient diet from delivery ; DEF II group, from the 15 th day of gestation. Body and brain weights, brain protein, DNA, RNA, plasma GOT and GPT, and catecholamines were measured. Effect of MAO inhibiting drug, pargyline, was determined. Brain protein, DNA, and RNA of offsprings of deficient groups were significantly lower than the control group, but RNA/ DNA, brain weight/DNA, and protein/DNA show that cell number were more affected than cell size by the pyridoxine deficiency during the 3rd week of gestation and lactation. Plasma GOT activities were more significantly different than plasma GPT between the control and deficient group. Brain norepinephrine of offsprings of deficient group were significantly lower than the control, but brain dopamine content was not significantly different from the control. At 2nd and 3rd week, norepinephrine was significantly depressed in deficient groups. Pargyline treatment affected a 1.2 fold increase in catecholamines in 3hr while the control had a 1.5 fold increase. Thus norepinephrine and dopamine synthesis was depressed in the deficient groups. Dopaminergic neurons may be less dependent on pyridoxine level than neurons from norepinephrine. Pyridoxine deficiency in maternal diet is not so critical to brain catecholamines of offspring except to the neonatal rats.

• Annals of Clinical Neurophysiology
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• v.23 no.2
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• pp.69-81
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• 2021

Cortico-cortical evoked potential (CCEP) mapping is a rapidly developing method for visualizing the brain network and estimating cortical excitability. The CCEP comprises the early N1 component the occurs at 10-30 ms poststimulation, indicating anatomic connectivity, and the late N2 component that appears at < 200 ms poststimulation, suggesting long-lasting effective connectivity. A later component at 200-1,000 ms poststimulation can also appear as a delayed response in some studied areas. Such delayed responses occur in areas with changed excitability, such as an epileptogenic zone. CCEP mapping has been used to examine the brain connections causally in functional systems such as the language, auditory, and visual systems as well as in anatomic regions including the frontoparietal neocortices and hippocampal limbic areas. Task-based CCEPs can be used to measure behavior. In addition to evaluations of the brain connectome, single-pulse electrical stimulation (SPES) can reflect cortical excitability, and so it could be used to predict a seizure onset zone. CCEP brain mapping and SPES investigations could be applied both extraoperatively and intraoperatively. These underused electrophysiologic tools in basic and clinical neuroscience might be powerful methods for providing insight into measures of brain connectivity and dynamics. Analyses of CCEPs might enable us to identify causal relationships between brain areas during cortical processing, and to develop a new paradigm of effective therapeutic neuromodulation in the future.

• Proceedings of the Korean Society of Toxicology Conference
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• 2006.11a
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• pp.55-64
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• 2006

The fetal central nervous system (CNS) is sensitive to diverse environmental factors, such as alcohol, heavy metals, irradiation, mycotoxins, neurotransmitters, and DNA damage, because a large number of processes occur during an extended period of development. Fetal neural damage is an important issue affecting the completion of normal CNS development. As many concepts about the brain development have been recently revealed, it is necessary to compare the mechanism of developmental abnormalities induced by extrinsic factors with the normal brain development. To clarify the mechanism of fetal CNS damage, we used one experimental model in which 5-azacytidine (5AZC), a DNA damaging and demethylating agent, was injected to the dams of rodents to damage the fetal brain. 5AzC induced cell death (apoptosis)and cell cycle arrest in the fetal brain, and it lead to microencephaly in the neonatal brain. We investigated the mechanism of apoptosis and cell cycle arrest in the neural progenitor cells in detail, and demonstrated that various cell cycle regulators were changed in response to DNA damage. p53, the guardian of genome, played a main role in these processes. Further, using DNA microarray analysis, tile signal cascades of cell cycle regulation were clearly shown. Our results indicate that neural progenitor cells have the potential to repair the DNA damages via cell cyclearrest and to exclude highly affected cells through the apoptotic process. If the stimulus and subsequent DNA damage are high, brain development proceeds abnormally and results in malformation in the neonatal brain. Although the mechanisms of fetal brain injury and features of brain malformation afterbirth have been well studied, the process between those stages is largely unknown. We hypothesized that the fetal CNS has the ability to repair itself post-injuring, and investigated the repair process after 5AZC-induced damage. Wefound that the damages were repaired by 60 h after the treatment and developmental processes continued. During the repair process, amoeboid microglial cells infiltrated in the brain tissue, some of which ingested apoptotic cells. The expressions of genes categorized to glial cells, inflammation, extracellular matrix, glycolysis, and neurogenesis were upregulated in the DNA microarray analysis. We show here that the developing brain has a capacity to repair the damage induced by the extrinsic stresses, including changing the expression of numerous genes and the induction of microglia to aid the repair process.

• BMB Reports
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• v.49 no.11
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• pp.629-634
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• 2016

Transmembrane and coiled-coil domain family 3 (TMCC3) has been reported to be expressed in the human brain; however, its function is still unknown. Here, we found that expression of TMCC3 is higher in human whole brain, testis and spinal cord compared to other human tissues. TMCC3 was expressed in mouse developing hind brain, lung, kidney and somites, with strongest expression in the mesenchyme of developing tongue. By expression of recombinant TMCC3 and its deletion mutants, we found that TMCC3 proteins self-assemble to oligomerize. Immunostaining and confocal microscopy data revealed that TMCC3 proteins are localized in endoplasmic reticulum through transmembrane domains. Based on immunoprecipitation and mass spectroscopy data, TMCC3 proteins associate with TMCC3 and 14-3-3 proteins. This supports the idea that TMCC3 proteins form oligomers and that 14-3-3 may be involved in the function of TMCC3. Taken together, these results may be useful for better understanding of uncharacterized function of TMCC3.

• 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.

• Applied Microscopy
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• v.18 no.2
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• pp.119-131
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• 1988

The purpose of this study was to investigate the differentiation and degeneration of neurons in developing chick embryo. The activity of acid phosphatase(ACP) was measured and cytochemical study of ACP and ultrastructural changes were observed in prosencephalon, mesencephalon and rhombencephalon from day 4 to day 19 of incubation. As a result, the activity of ACP of all brain region was tend to increase from day 4 to day 19. On day 13, activities of ACP of mesencephalon and rhombencephalon were increased greatly and activity of ACP was decreased each region on day 17. On electron microscopic examination, the reaction product of ACP were localized at GERL complex, lysosome, Golgi body and vacuoles of neurons. Morphologically, disrupted nuclear envelope, mitochondrial destruction, vacuolization and ribosomal crystalization were observed.

• Applied Microscopy
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• v.42 no.3
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• pp.142-146
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• 2012

Doublecortin (DCX) is a microtuble-associated protein that is required for the migration of immature neuroblasts within the chick and mammalian brain. Although it is generally thought that DCX is expressed only in the neuroblasts, some mature neurons maintain DCX expression; for example, horizontal cells in adult rat retina. In this study, we demonstrate that retinal neural progenitors in the early embryonic stage of the chick also expressed DCX, as do developing ganglion cells and horizontal cells in later stages of development. These findings raise the possibility of a role for DCX in retinal neural progenitors, before they become specialized into neuroblasts in the chick.

• Journal of Korea Multimedia Society
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• v.23 no.7
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• pp.862-869
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• 2020

This study attempted to analyze human brain responses toward visual content through EEG signals and intended to measure brain wave reactions of different age groups to determine the sexuality level of the media. The experimental stimuli consist of three different video footage (rated ages 12, 15, and 18) to analyze how subjects react in situations where they actually watch sexual content. For measuring and analyzing brain wave reactions, EEG equipment records alpha, beta, and gamma wave responses of the subjects' left and right frontal lobes, temporal lobes, and occipital lobes. The subjects of this study were 28 total and they are divided into two groups. The experiment configures a sexual content classification scale with age or gender as a discriminating variable and brain region-specific response frequencies (left/right, frontal/temporal/occipital, alpha/beta/gamma waves) as independent variables. The experimental results showed the possibility of distinguishing gender and age differences. The apparent differences in brain wave response areas and bands among high school girls, high school boys, and college students are found. Using these brain wave response data, this study explored the potential of developing algorithm for measurement of age-specific responses to sexual content and apply it as a film rating.