• Korean Journal of Veterinary Research
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• v.37 no.1
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• pp.189-194
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• 1997

The life cycle of Theileria sergenti(T sergenti) in cattle, especially Korean native cattle, was not proved clearly. To find schizont stage in the life cycle of T sergenti in Korean cattle, T sergenti schizonts in the cells of parotid lymph nodes from 10 adult Korean cattle were examined. Lymphoid cells which were separated from these lymph nodes were cytocentrifuged to observe the parasites in the cells. T sergenti schizonts were detected in the cells of lymph nodes of 6 cattle out of them by IFA(Indirect Fluorescent Antibody) test and Giemsa stain. By peroxidase stain, the cells which contain schizonts were proved lymphoid cells. T sergenti schizonts identified by IFA test were able to be restained by Giemsa stain. Also, merozoites were observed in peripheral blood of the same 6 cattle that had schizonts, by giemsa stain, but not observed in the 4 cattle that had not been detected schizonts. As a part of life cycle of T sergenti, schizonts were observed in the lymphoid cells of Korean cattle.

• Animal cells and systems
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• v.11 no.1
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• pp.23-31
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• 2007

Programmed cell death was characterized in the silkworm thoracic ganglia TG1, TG2 and TG3 during postembryonic periods by TUNEL assay. Apoptotic cells were detected in the three TGs of all larval stages except for day-1, 2 1st instar larvae, in which no apoptotic cells were found. From day-7 5th larva, the numbers of apoptotic cells were dramatically increased and peaked on day-1 pupa and day-2 pupa and then abruptly decreased. Apoptotic cells finally disappeared in day-1 adult. In-vivo injection of 20-hydroxyecdysone (20E) into day-8 5th larva resulted in a striking decrease of apoptotic cells. Actinomycin D (Act D) or cycloheximide (CHX), injected into hemolymph of day-8 5th larva, resulted in a decrease of apoptotic cells in the three TGs. Injection of caspase-8 and -3 inhibitors also blocked cellular apoptosis. These results will provide valuable information for understanding of cellular changes in the three TGs during metamorphosis of the insect species.

• International Journal of Oral Biology
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• v.33 no.2
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• pp.59-64
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• 2008

This study was designed to investigate the changes in the properties of the neuronal setm cells or progenitor cells associated with age-related decline in neurogenesis of the hippocampal dentate gyrus (DG). Active whole cells cycle marker Ki67 (a marker of whole cell cycle)-positive and S phase marker bromodeoxyuridine (BrdU)-positive. Neural stem cells gradually were reduced in the hippocampal subgranular zone (SGZ) in an age-dependant manner after birth (from P1 month to P1 year). The ratio of BrdUpositivecells/Ki67-positive cells was gradually enhanced in an age-dependent manner. The ratio of Ki67-positive cells/accu-mulating BrdU-positive cells at 3 hrs after BrdU injection was injected once a day for consecutive 5 days gradually decreased during ageing. TUNEL- and caspase 3 (apoptotic terminal caspase)-positive cells gradually decreased in the dentate SGZ during ageing and immunohistochemical findings of glial fibrillary acid protein (GFAP) were not changed during ageing. NeuN, a marker of mature neural cells, and BrdU-double positive cells gradually decreased in an age-dependent manner but differentiating ratio and survival rate of cells were not changed at 4 wks after BrdU injection once a day for consecutive 5 days. The number of BrdU-positive cells migrated from the hippocampal SGZ into granular layer and its migration speed was gradually declined during ageing. These results suggest that the adult neurogenesis in the mouse hippocampal DG gradually decrease through reducing proliferation of neural stem cells accompanying with cells cycle change and reduced cells migration rather than changes of differentiation.

• Environmental Mutagens and Carcinogens
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• v.26 no.3
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• pp.69-76
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• 2006

2,3,7,8-Tetrachlorodibenzo-$\rho$-dioxin(TCDD) is a ubiquitous, persistent environmental contaminant and the most powerful carcinogen categorized by IARC. Although the mechanism of carcinogenesis by TCDD is poorly understood, several studies have shown that the skin is one of target organs far TCDD. In this study, we investigated the neoplastic transformation of human keratinocyte-derived cell line, HaCaT, by chemical transformation method using N-methyl-N'-nitro-N-nitrorsoguanidine(MNNG) and TCDD. We found that subsequent exposure to TCDD for 3 weeks after initial exposure to MNNG markedly induced transformed cells. It was suggested that TCDD can act as a potent promoter in HaCaT cells. Furthermore, these transformed cells showed morphological alternations in soft agar and increased telomerase activity. Therefore, the TCDD treatment of HaCaT cells by initiated with MNNG could promote neoplastic transformation without stimulation by exogenous growth factors. As a result, TCDD had a strong potency as a promoter in nontumorigenic immortalized human epidermal keratinocytes.

• IMMUNE NETWORK
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• v.4 no.2
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• pp.94-99
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• 2004

Background: We previously reported that ginsan, a polysaccharide extracted from Panax ginseng had an immunostimulatory activity such as mitogenic activity, activation of macrophages and killer cells, and production of a variety of cytokines which resulted in antitumor and antiseptic effects. We further purified $\alpha$-(1$\longrightarrow$6)-glucan and $\beta$-(2$\longrightarrow$6)-fructan from the ginsan with size exclusion and ion-exchange column chromatography successively. In this study, we performed the structure-based activity of ginsan by comparison with known polysacchrides such as $\beta$-glucan, curdlan, laminarin, levan, dextran, lentinan and OK-432. Methods: To investigate the immunostimulatory activity of several polysaccharide compounds, we investigated the stimulation of lymphocytes proliferation, the generation of activated killer cells and the secretion of nitrites from activated macrophages. Results: Of polysaccharides tested, curdlan and ginsan stimulated lymphocyte proliferation, suggesting that the molecular weight and composition of polysaccharide are dependent on the mitogenic activity. The production of nitric oxide was significantly increased in curdlan, levan, ginsan and its fraction, indicating that fructan has also capacity to activate macrophages and may devote to kill pathogens. In addition, the activation of macrophages was seemed to be independent of molecular weight of polysaccharide. The generation of AK cells was exhibited in order of curdlan, OK-432> F1, ginsan, F3> levan> etc. The AK activity may be dependent on molecular weight and composition of polysaccharides. Conclusion: Unfortunately, purified polysaccharide from ginsan were less active on immunostimulatory activity than mixed compounds of polysaccharides. From the viewpoint of structure and activity relationships, we found several characteristic features.

• Journal of Mushroom
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• v.17 no.2
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• pp.70-77
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• 2019

This study was carried out to analyze the physiological activities of wild mushroom extracts collected from the Gangwon-do, Gyeonggi-do, and Chungcheongbuk-do provinces in Korea. Among the wild mushroom extracts, those of Clitocybe robusta and Leucopaxillus giganteus (OK829) showed the highest DPPH radical scavenging activities. Nitrite scavenging activity of the L. giganteus extract (OK811) was determined to be 64.1%, which is considerably higher than those of the other mushroom extracts analyzed in this study. The total polyphenol levels in Suillus granulatus, L. giganteus (OK829), and Amanita manginiana extracts were found to be 19.7 mg GAE/g, 20.2 mg GAE/g, and 22.3 mg GAE/g, respectively. To determine their anti-inflammatory effects, nitric oxide production, and cell viability, NO measurement and MTT assays were performed using lipopolysaccharide (LPS)-treated RAW 264.7 cells. The levels of nitric oxide (NO) produced by the C. robusta and Hypholoma fasciculare extracts were remarkably lower than those produced by the others. In our MTT assay, the extracts of S. granulatus, L. giganteus (OK811), and Lactarius chrysorrheus showed high cell viabilities of 40.3%, 48.3%, and 43.2%, respectively. These results can provide the fundamental data for extracting useful compounds from wild mushrooms.

• Preventive Nutrition and Food Science
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• v.5 no.2
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• pp.114-118
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• 2000

The inhibitory effects of doenjang extracts and linoleic acid(LA) which was identified as one of the active compounds in doenjang on the growth of human cancer cells were studied, comparing to the actions on normal cells. Methanol extract and hexane fraction from doenjang exhibited the strong growth inhibitory effect on HT-29 human colon carcinoma cells. Inhibitory effects of chloroform, ethyl acetate, butanol and aqueous fractions on the cancer cells were observed, moderately or weakly. When cell counts of SNU-C$_1$human colon carcinoma cells were determined daily for 6 days, the inhibitory effect of hexane fraction on this cell line was higher than that of the methanol extract from doenjang. LA completely suppressed the growth of SNU-C$_1$cells after 4 days, while conjugated linoleic acid(CLA) resulted in 98% inhibition after 6 days. With the addition of LA and other free fatty acids such as stearic acid, oleic acid, linolenic acid and ${\gamma}$-linolenic acid (${\gamma}$-LnA) to the culture system, the growth of HT-29 cells and SNU-C$_1$cells was greatly suppressed after 6 days. Inhibitory effects of LA ${\gamma}$-LnA on the growth of these cells were stronger than other fatty acids. On the growth of AZ-521 human gastric carcinoma cells, LA and CLA completely cuppressed the growth of the cells after 4 days and 3 days, respectively. At the level of 0.001%~0.01% of LA, there was no cytotoxic effect on normal rat kidney cells and normal intestine human cells. These results showed that LA, a major active compound of doenjang, had strong inhibitory effects on the growth of human cancer cells without damaging normal cells.

• Journal of Korean Neurosurgical Society
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• v.30 no.8
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• pp.963-969
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• 2001

Objectives : Cord blood stem cells have been widely used as donor cells for bone marrow transplantation recently. These cells can give rise to a variety of hematopoietic lineages to repopulate the blood. Recent observations reveal that some bone marrow cells and bone marrow stromal cells(MSCs) can grow to become either neurons or glial cells. It is, however, unclear whether or not there exists stems cells which can differentiate into neurons in the blood during the early stages of postnatal life. Methods : Human cord blood stem cells were prepared from human placenta after full term delivery. To induce neuronal differentiation of stem cells, ${\beta}$-mercaptoethanol was treated. To confirm the neuro-glial characteristics of differentiated stem cells, immunocytochemical stain for NeuN, neurofilament, glial fibrillary acidic protein(GFAP), microtubule associated protein2(MAP2) was performed. RT-PCR was performed for detecting nestin mRNA and MAP2 mRNA. Results : We showed in this experiment that neuro-glial markers(NeuN, neurofilament, MAP2, GFAP) were expressed and axon-like cytoplasmic processes are elaborated in the cultured human cord blood stem cells prepared from new born placenta after full term delivery. Nestin mRNA was also detected in fresh cord blood monocytes. Conclusions : These results suggest that human cord blood derived stem cells may be potential sources of neurons in early postnatal life.

• Proceedings of the Zoological Society Korea Conference
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• 1998.10b
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• pp.235.1-235
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• 1998

No Abstract, See Full Text

• Proceedings of the Korean Society of Life Science Conference
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• 2002.09a
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• pp.41-41
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• 2002