• YAKHAK HOEJI
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• v.50 no.6
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• pp.358-366
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• 2006

The aim of this study was to investigate the protective effects of glycynhizin, active glycosides of Glycyrrhizae Radix, and baicalin, bioactive flavonoid isolated from Scutellariae Radix, on hepatocyte injury induced by carbon tetrachloride(CCl$_4$, 10 mM), tert-butyl hydroperoxide (TBH, 0.5 mM), and D-galactosamine (GaIN, 30 mM). Primary cultures of rat hepatocyte (18 hr cultured) were treated with CCl$_4$, TBH, or GaIN and various concentrations (0.1, 1, 10, and 100 ${\mu}$M) of glycyrrhizin or baicalin. Activity was accessed by determining the release of lactate dehydrogenase (LDH) and aminotransferses. CCl$_4$ significantly increased the levels of LDH, alanine aminotransferase (ALT), and aspartate aminotransferase(AST) and these increases were prevented by baicalin concentrations of 0.1,1, and 100 ${\mu}$M. The increases in ALT and AST levels were reduced by glycyrrhizin concentration of 100 ${\mu}$M. The level of LDH was markedly increased by TBH, and this increase was reduced by both glycyrrhizin and baicalin. ALT and AST levels were increased by TBH, which were prevented by glycynhizin and bacalin, respectively: GaIN markedly increased the levels of LDH, ALT and AST These increases was significantly reduced by both glycyrrhizin and baicalin. These results suggest that glycynhizin and baicalin possess the hepatoprotective activity.

• Biomolecules & Therapeutics
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• v.29 no.2
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• pp.144-153
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• 2021

Astrocytes play various important roles such as maintaining brain homeostasis, supporting neurons, and secreting inflammatory mediators to protect the brain cells. In aged subjects, astrocytes show diversely changed phenotypes and dysfunctions. But, the study of aged astrocytes or astrocytes from aged subjects is not yet sufficient to provide a comprehensive understanding of their important processes in the regulation of brain function. In this study, we induced an in vitro aged astrocyte model through late passage cultivation of rat primary cultured astrocytes. Astrocytes were cultured until passage 7 (P7) as late passage astrocytes and compared with passage 1 (P1) astrocytes as early passage astrocytes to confirm the differences in phenotypes and the effects of serial passage. In this study, we confirmed the morphological, molecular, and functional changes of late passage astrocytes showing aging phenotypes through SA-β-gal staining and measurement of nuclear size. We also observed a reduced expression of inflammatory mediators including IL-1β, IL-6, TNFα, iNOS, and COX2, as well as dysregulation of wound-healing, phagocytosis, and mitochondrial functions such as mitochondrial membrane potential and mitochondrial oxygen consumption rate. Culture-conditioned media obtained from P1 astrocytes promoted neurite outgrowth in immature primary cultures of rat cortices, which is significantly reduced when we treated the immature neurons with the culture media obtained from P7 astrocytes. These results suggest that late passage astrocytes show senescent astrocyte phenotypes with functional defects, which makes it a suitable model for the study of the role of astrocyte senescence on the modulation of normal and pathological brain aging.

• KSBB Journal
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• v.14 no.2
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• pp.198-204
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• 1999

Asymbiotic bacterium with highly effective toxins was isolated from entomopathogenic nematode Steinernema glaseri which has been widely used against various soil-inhabiting pests. The symbiont of S. glaseri was identified as Xenorhabdus nematophilus sp. by using several biochemical and physiological tests. When this strain was released into the hemolymph of insect larva, it produced highly toxic substances and killed the larva within 2 days. Two colony forms that differed n some biochemical characteristics were observed when cultures in vitro. Phase l colonies were mucid and difficult to be dispersed in liquid. Phase II was not mucoid and was easily dispersed in liquid. It did not adsorb neutral red or bromothymol blue. Rod-shaped cell size was highly variable between two phases, ranging 2-10 ${\mu}{\textrm}{m}$. It was also found that only infective-stage nematodes can carry only primary-phase Xenorhabdus in their intestine.

• Toxicological Research
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• v.16 no.1
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• pp.63-66
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• 2000

The effects of acute ethanol on the high K+ induced $Ca^{2+}}$ signals were examined from primary cultures of cerebellar granule neurons. $Ca^{2+}}$ signals were measured with Calcium Green-1 based microscopic video imaging. Because $Ca^{2+}}$ signal was low in most of granule neurons without stimuli, high KCI was used for depolarization. In most case, acute exposure to ethanol reduced the peak amplitude of the $Ca^{2+}}$ signals, induced by high K+, even though low concentration of ethanol(2~10mM) was used and the effects lasted more than 30min. In was also possible to see differences of ethanol inhibition, i.e. the temporal pattern of $Ca^{2+}}$ signal reductions and the strength of inhibition of $Ca^{2+}}$ signals in cerebellar granule neurons. These results indicate that low concentration of ethanol has diverse actions on the $Ca^{2+}}$ signals in cerebellar granule neurons.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.1
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• pp.42-45
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• 2002

Cultures of primary human alveolar bone-derived cells were established from alveolar bone chips obtained from normal individuals undergoing tooth extraction. These cells were expanded in vitro until passage 3 and used for the in vivo assays. Cells were loaded into transplantation vehicles, and transplanted subcutaneously into immunodeficient mice to study the capacities of human alveolar bone-derived cells to form bone in vivo. Transplants were harvested 12 weeks after transplantation and evaluated histologically. Of 10 human alveolar bone-derived cell transplants, two formed a bone-like tissue that featured osteocytes and mineral. Eight of the ten formed no osseous tissue. These results show that cells from normal human alveolar bone are capable of forming bone-like tissue when transplanted into immunodeficient mice.

• The Plant Pathology Journal
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• v.31 no.2
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• pp.186-191
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• 2015

Diatoms are a major component of the biological community, serving as the principal primary producers in the food web and sustaining oxygen levels in aquatic environments. Among marine planktonic diatoms, the cosmopolitan Skeletonema costatum is one of the most abundant and widespread species in the world's oceans. Here, we report the basic characteristics of a new diatom-infecting S. costatum virus (ScosV) isolated from Jaran Bay, Korea, in June 2008. ScosV is a polyhedral virus (45-50 nm in diameter) that propagates in the cytoplasm of host cells and causes lysis of S. costatum cultures. The infectivity of ScosV was determined to be strain- rather than species-specific, similar to other algal viruses. The burst size and latent period were roughly estimated at 90-250 infectious units/cell and <48 h, respectively.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.124-124
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• 1995

Cisplatinum is often effective in cancer treatment, but potent nephrotoxicity limits its clinical use. We have, therefore, developed new anticancer drugs that contain platinum. We have synthesized six new platinum compounds based on Figure 1. Drugs were initially administrated at 5${\times}$10$\^$-4/M with 48 hours exposure in monolayer cultures of primary rabbit proximal tubular cells and human renal cortical cells with the M.T.T. endpoint to measure toxicity. Drug concentrations of 10$\^$-3/M, 10$\^$-4/M, and 10$\^$-5/M with 72 hours exposure were used for human renal cortical tissues in 7 weeks histoculture with toxicity measured by the glucose-consumption endpoint. From these studies, we determined that the new platinum drugs have lower nephrotoxicity than cisplatinum. Drugs D, E, and H. have lower nephrotoxicity than the other new drugs. We are currently measuring the anticancer efficacy of drugs D, E, and H.

• Archives of Pharmacal Research
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• v.18 no.5
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• pp.295-300
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• 1995

These studies were designed to examine the effects of ginsenosides on glutamate neurotansmission. In primary cultures of rat cerebellar granule cells, ginsenosides (Rb1, Rc did not Rg1, $500\mug/ml$) increased glutamate release which was measured by HPLC. but HPLC, but Re did not shwo an elevation of glutamate release. However, all of these ginsenosides down-regulated N-methyl-D-aspartate (NMDA)-induced glutamate release. Rc strongly increased glutamate release and elevated intracellular clcium concentrations $([Ca_{2+}]_i)$ which was measured by ratio fluorometry with FURA-2AM. These results indicate that ginsenosides have a homeostatic effect on glutamate neurotransmission, and there is a structure-function relationship among the ginsenosides tested.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.123-123
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• 2003

Primary cultures of rat fetus brain exhibit phenotypes of neuron, oligodendrocyte, and astrocyte from "neurospheres". To understand the role of mitogen-activated protein kinase (MAPK) cascade and gap junctional intercellular communication (GJIC) in the differentiation of neurosphere-derived astrocyte, we investigated the effects of 12-O-tetradecanoylphorbol-13-acetate (TPA) on the cultured astrocyte morphology.(omitted)

• Archives of Pharmacal Research
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• v.20 no.6
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• pp.529-532
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• 1997

A $CHCl_3$:MeOH extract of the fruit of Lycium chinense Mill. (Solanaceae) was found to afford significant protection against carbon tetrachloride-induced toxicity in primary cultures of rat hepatocytes. Subsequent activity-guided fractionation resulted in the isolation of zeaxanthin and zeaxanthin dipalmitate as antihepatotoxic components. Incubation of injured hepatocytes with zeaxanthin dipalmitate reduced the levels of glutamic pyruvic transaminase (GPT) and sorbitol dehydrogenase (SDH) released from damaged cells to 60.5% and 76.3% of those released from untreated controls, respectively. Zeaxanthin also reduced the levels of GPT and SDH to 68.5% and 61.3% of the levels of those released from the untreated contro. The results confirm the hepatoprotective activities of zeaxanthins. Antihepatotoxic activities of zeaxanthins are comparable to that of silybin.