• BMB Reports
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• v.34 no.2
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• pp.144-149
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• 2001

Antioxidant enzymes, scavengers of the reactive oxygen intermediate (ROI), are involved in numerous defense systems in cells. In the present study, we investigated the effects of the hot-water extracts of two medicinally potent mushrooms (Ganoderma lucidum and Phellinus linteus) on the activity and expression of antioxidant enzymes in vitro and in vivo. The mushroom extracts stimulated the catalase activity in a dose-dependent manner in vitro, whereas the other antioxidant enzymes (such as superoxide dismutase (SOD), glutathione peroxidase (GPx)) were unaffected by the extracts. The catalytic activity of catalase in the liver and brain was significantly increased after the oral treatment of the mushroom extracts (2.5 g/kg) to ICR mice for 2 months. Western blot analysis of the liver and brain tissues revealed that the expression level of catalase in the mice, treated with both mushroom extracts, was significantly increased compared to that of the control mice. However, the level of the SOD expression in the mice treated with the natural product extracts was unchanged under the same experimental conditions. Although the mechanisms for the stimulatory effect of the catalase expression by these extracts remains unclear, these results suggest that the ingredients of the Ganoderma lucidum and Phellinus linteus extracts act as an activator of catalase, and regulate the expression of catalase at the translational or transcriptional level.

• Korean Journal of Cognitive Science
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• v.24 no.3
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• pp.271-300
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• 2013

Human and animals are born with an intuitive ability to determine approximate numerosity. This ability is termed approximate number sense (hereafter, number sense). Evolutionarily, number sense is thought to be an essential ability for hunting, gathering and survival. According to previous research, children with mathematical learning disability have impaired number sense. On the other hand, individuals with more accurate number sense have higher mathematical achievement. These results support the hypothesis that number sense provides a basis for the development of mathematical cognition. Recently, researchers have been examining whether number sense training can lead to enhancement in mathematical achievement and changes in brain activity in relation to mathematical problem solving. Numerosity which basically represents discontinuous quantity is expected to be closely related to continuous quantity such as representations of space and time. A theory of magnitude (ATOM) states that processing of number, space and time is based on a common magnitude system in the posterior parietal cortex, especially the intraparietal sulcus. The present paper introduces current literature and future directions for the study of the common magnitude system.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.10
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• pp.4331-4338
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• 2014

$N^1$-(2, 5-dimethoxyphenyl)-$N^8$-hydroxyoctanediamide (N25) is a novel SAHA cap derivative of HDACi, with a patent (No. CN 103159646). This invention is a hydroxamic acid compound with a structural formula of $RNHCO(CH_2)6CONHOH$ (wherein R=2, 5dimethoxyaniline), a pharmaceutically acceptable salt which is soluble. In the present study, we investigated the effects of N25 with regard to drug distribution and molecular docking, and anti-proliferation, apoptosis, cell cycling, and $LD_{50}$. First, we designed a molecular approach for modeling selected SAHA derivatives based on available structural information regarding human HDAC8 in complex with SAHA (PDB code 1T69). N25 was found to be stabilized by direct interaction with the HDAC8. Anti-proliferative activity was observed in human glioma U251, U87, T98G cells and human lung cancer H460, A549, H1299 cells at moderate concentrations ($0.5-30{\mu}M$). Compared with SAHA, N25 displayed an increased antitumor activity in U251 and H460 cells. We further analyzed cell death mechanisms activated by N25 in U251 and H460 cells. N25 significantly increased acetylation of Histone 3 and inhibited HDAC4. On RT-PCR analysis, N25 increased the mRNA levels of p21, however, decreased the levels of p53. These resulted in promotion of apoptosis, inducing G0/G1 arrest in U251 cells and G2/M arrest in H460 cells in a time-dependent and dose-dependent manner. In addition, N25 was able to distribute to brain tissue through the blood-brain barrier of mice ($LD_{50}$: 240.840mg/kg). In conclusion, our findings demonstrate that N25 will provide an invaluable tool to investigate the molecular mechanism with potential chemotherapeutic value in several malignancies, especially human glioma.

• ALGAE
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• v.31 no.1
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• pp.73-84
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• 2016

Marine organisms are frequently used to be harmful and have lower side effects than synthetic drugs. The cognitive improving efficacy of gamma aminobutyric acid-enriched fermented Saccharina japonica (FSJ) on the memory deficient rats, which were induced by trimethyltin chloride (TMT), was investigated by assessing the Morris water maze test and by performing choline acetyltransferase (ChAT), cAMP response element binding protein (CREB), and brain derived neurotrophic factor (BDNF) immunohistochemistry. The neurite outgrowth of Neuro2a cells was assessed in order to examine the underlying mechanisms of the memory enhancing effects of FSJ. Treatment with FSJ tended to shorten the latency to find the platform in the acquisition test of the Morris water maze at the second and fourth day compared to the control group. In the probe trial, the FSJ treated group increased time spent in the target quadrant, compared to that of the control group. Consistent with the behavioral data, these treatments recovered the loss of ChAT, CREB, and BDNF immunepositive neurons in the hippocampus produced by TMT. Treatment with FSJ markedly stimulated neurite outgrowth of the Neuro2a cells as compared to that of the controls. These findings demonstrate that FSJ may be useful for improving the cognitive function via regulation of neurotrophic marker enzyme activity.

• Korean Journal of Biological Psychiatry
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• v.20 no.4
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• pp.166-178
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• 2013

Objectives Alteration of epigenetic effects of testosterone during early development was suggested as an ancillary mechanism for the genesis of schizophrenia. EEG coherence was thought to be a marker for cerebral laterality of which important determinant was testosterone during early development. We studied sex-related differences of EEG coherences between patients with schizophrenia and controls to examine the sex effects in the genesis of schizophrenia. Methods EEG was recorded in 35 patients with schizophrenia and 46 healthy controls in the eyes closed resting state. Pair-wise EEG coherences were calculated over delta, theta, alpha, beta and gamma frequency bands. To examine the differences of EEG coherence according to sex in each group, ANCOVA was performed using Statistical Analysis system (SAS, Ver 9.3) and R (Ver 2.15.2). Results Healthy control males showed more increased right intrahemispheric coherences than healthy control females in delta, theta, alpha and beta frequency bands. In patients with schizophrenia, this male dominant pattern in right intrahemispheric coherences was attenuated especially in alpha and beta bands. Healthy control females showed more increased interhemispheric coherences than healthy control males in delta, theta, beta and gamma frequency bands. In patients with schizophrenia, these female dominant patterns in interhemispheric coherences were attenuated especially in delta, theta, and beta bands, which were commonly observed in frontal to central areas. Conclusion Sex differences in resting EEG coherences were attenuated in schizophrenia patients. These results imply that sex-related aberrant cerebral lateralization might exist in patients with schizophrenia, which are partly due to sex hormones via epigenetic mechanisms.

• Molecules and Cells
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• v.20 no.3
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• pp.315-324
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• 2005

Pain is an unpleasant sensation experienced when tissues are damaged. Thus, pain sensation in some way protects body from imminent threat or injury. Peripheral sensory nerves innervated to peripheral tissues initially respond to multiple forms of noxious or strong stimuli, such as heat, mechanical and chemical stimuli. In response to these stimuli, electrical signals for conducting the nociceptive neural signals through axons are generated. These action potentials are then conveyed to specific areas in the spinal cord and in the brain. Sensory afferent fibers are heterogeneous in many aspects. For example, sensory nerves are classified as $A{\alpha}$, $-{\beta}$, $-{\delta}$ and C-fibers according to their diameter and degree of myelination. It is widely accepted that small sensory fibers tend to respond to vigorous or noxious stimuli and related to nociception. Thus these fibers are specifically called nociceptors. Most of nociceptors respond to noxious mechanical stimuli and heat. In addition, these sensory fibers also respond to chemical stimuli [Davis et al. (1993)] such as capsaicin. Thus, nociceptors are considered polymodal. Recent advance in research on ion channels in sensory neurons reveals molecular mechanisms underlying how various types of stimuli can be transduced to neural signals transmitted to the brain for pain perception. In particular, electrophysiological studies on ion channels characterize biophysical properties of ion channels in sensory neurons. Furthermore, molecular biology leads to identification of genetic structures as well as molecular properties of ion channels in sensory neurons. These ion channels are expressed in axon terminals as well as in cell soma. When these channels are activated, inward currents or outward currents are generated, which will lead to depolarization or hyperpolarization of the membrane causing increased or decreased excitability of sensory neurons. In order to depolarize the membrane of nerve terminals, either inward currents should be generated or outward currents should be inhibited. So far, many cationic channels that are responsible for the excitation of sensory neurons are introduced recently. Activation of these channels in sensory neurons is evidently critical to the generation of nociceptive signals. The main channels responsible for inward membrane currents in nociceptors are voltage-activated sodium and calcium channels, while outward current is carried mainly by potassium ions. In addition, activation of non-selective cation channels is also responsible for the excitation of sensory neurons. Thus, excitability of neurons can be controlled by regulating expression or by modulating activity of these channels.

• Proceedings of the Ginseng society Conference
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• 1998.06a
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• pp.1-11
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• 1998

Ameliorating mechanisms of red ginseng on learning deficits were investigated in the following 3 experiments; its effects on 1) place learning deficits in aged rats and in young rats with selective hippocampal lesions (behavioral study), 2) long-term potentiation in the hippocampal formation (neuro- physiological study), and 3) ChAT (choline acetyl transferase) activity in various brain regions of aged rats (pharmacological study). In the behavioral study, first, performance in the place learning tasks were compared among 3 groups of young and aged rats; control young intact rats (10-12 week old) treated with water, aged rats (28-32 month old) treated with water, and aged rats (28-32 month old) treated with red ginseng (100 mghglday) suspended in water. Second, performance in the place learning tasks was compared among 3 groups of young rats; control intact rats treated with water, rats with bilateral hippocampal lesions treated with water, and rats with bilateral hippocampal lesions treated with red ginseng (100 mg/kg/day). Each rat in these 2 behavioral experiments was tested with the 3 types of the place learning tasks in a circular open field using intracranial self-stimulation (ICSS) as reward. The ICSS reward was delivered if the rat (1) moved distance of 100-160 cm (DMT): (2) entered an experiment-determined reward place within the open field, and this place was randomly varied in sequential trials (RRPST); or (3) entered 2 specific places, and did a shuttle behavior between the 2 places (PLT). Performance of the aged rats in the ginseng group was not significantly different from that of control young rats in ICSS (current intensity, bar press rates), DMT and RRPST. However, treatment with red ginseng significantly ameliorated place-navigation learning deficits in aged rats in the PLT. Similarly, red ginseng ameliorated learning and memory deficits in young rats with hippocampal lesions in the same tasks. In the neurophysiological study using young rats, perfusion of hippocampal slices with non-sapon in fraction of red ginseng significantly enhanced magnitudes of the long-term potentiation (LfP) in the CA3 subfield. In the pharmacological study, treatment with red ginseng did not affect ChAT activity in aged rat brain including the hippocampal formation. These results strongly suggest that red ginseng ameliorates learning and memory deficits in aged rats through actions on the CA3 subfield of the hippocampal formation, which were independent of the presynaptic components of the cholinergic system

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.3 no.1
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• pp.46-55
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• 1992

The pathophysiology of developmental language disorder is a highly controversial matter. In order to investigate the neural mechanisms involved in developmental language disorders, the authors studied three dimensional regional cerebral blood flow(rCBF) using Tc-99mH-MPAO in 42 children with developmental language disorders. The results are summarized as follows : 1) 61.9% (26/42) of this series revealed decreased perfusion in SPECT. 2) Regions of hypoperfusion were seen in cerebral cortex(47.6%, 20/42), thalamus(33.3%, 14/42), basal ganglia(11.9%, 5/42) and cerebellum(7.1%, 3/42). This study suggests that developmental language disorder could be due to specific functional impairment of the local brain regions which could not detected by conventional investigations such as brain CT or EEG.

• Korean Journal of Food Science and Technology
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• v.53 no.6
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• pp.715-721
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• 2021

Cognitive impairment and Alzheimer's disease are serious social problems associated with the rising elderly population in Korea. 1,2,3,4,6-Penta-O-galloyl-β-ᴅ-glucopyranose (PGG) is a gallotannin isolated from medicinal plants such as Rhus chinensis. This study was performed to evaluate the effect of PGG on biomarkers related to cognitive function in human neuroblastoma SK-N-SH cells. Inhibition of acetylcholinesterase (AChE) activity is considered to be one of the main therapeutic strategies. PGG inhibited AChE activity in the test tube as well as in SK-N-SH cells. In addition, PGG induced protein and mRNA expression of brain-derived neurotrophic factor (BDNF), which is a mammalian neurotrophin that plays major roles in the development, maintenance, repair, and survival of neuronal populations. As one of the underlying molecular mechanisms that induce BDNF expression, PGG induced the activation of Ca²⁺/calmodulin (CaM)-dependent protein kinase II (CaMKII)-cAMP response element binding protein (CREB) pathway. In conclusion, PGG may be an useful material for improving cognitive function.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.32 no.4
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• pp.137-143
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• 2021

Objectives: Despite the growing concern regarding the adverse effects related to problematic smartphone use (PSU), little is known about underlying morphologic changes in the brain. The brainstem is a deep brain structure that consists of several important nuclei associated with emotions, sensations, and motor functions. In this study, we sought to examine the difference in the volume of brainstem substructures among adolescents with and without PSU. Methods: A total of 87 Korean adolescents participated in this study. The PSU group (n=20, age=16.2±1.1, female:male=12:8) was designated if participants reported a total Smartphone Addiction Proneness Scale (SAPS) score of ≥42, whereas the remaining participants were assigned to the control group (n=67, age=15.3±1.7, female:male=19:48). High-resolution T1 magnetic resonance imaging was performed, and the volume of each of the four brainstem substructures [midbrain, pons, medulla, and superior cerebellar peduncle (SCP)] was measured. Analysis of covariance was conducted to reveal group differences after adjusting for effects of age, gender, whole brainstem volume, depressive symptoms, and impulsivity. Results: The PSU group showed a significantly smaller volume of the SCP than the control group (F=8.273, p=0.005). The volume of the SCP and the SAPS score were negatively correlated (Pearson's r=-0.218, p=0.047). Conclusion: The present study is the first to reveal an altered volume of the brainstem substructure among adolescents with PSU. This finding suggests that the altered white matter structure in the brainstem could be one of the neurobiological mechanisms underlying behavioral changes in PSU.