• YAKHAK HOEJI
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• v.48 no.4
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• pp.241-246
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• 2004

Mercury is a widespread metal and consequently there are large populations that currently exposed to low levels of mercury. Endotoxin is a component of the gram-negative bacteria and promotes inflammatory responses. The present study was designed to determine the impact of mercury on lymphocytes phenotype populations and endotoxin-induced inflammatory cytokine expressions in immune organ, spleen and thymus. Male BALB/c mice were exposed continuously to 0, 0.3, 1.5, 7.5, or 37.5 ppm of mercuric chloride in drinking water for 14 days and at the end of the treatment period, lipopolysaccharide (LPS, 0.5 mg/kg) was injected intraperitoneally 2 h prior to euthanasia. The dose-range of mercury used did not cause hepatotoxicity. Mercury at 7.5 and 37.5 ppm dose-dependently decreased CD3$^{+}$ T lymphocytes in spleen; both CD4$^{+}$ and CD8$^{+}$ single positive lymphocyte populations were decreased. Exposure to 7.5 and 37.5 ppm of mercury decreased the CD8$^{+}$ T lymphocyte population in the thymus, whereas double positive CD4$^{+}$ / CD8$^{+}$ and CD4$^{+}$ thymocytes were not altered. Mercury altered LPS-induced inflammatory cytokine gene expressions such as, tumor necrosis factor $\alpha$, interferon ${\gamma}$, and interleukin-12 in spleen and thymus. Results indicated that decreases in T lymphocyte populations in immune organs and altered cytokine gene expression may contribute to the immune-modulative effects of inorganic mercury.ganic mercury.

• IMMUNE NETWORK
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• v.15 no.3
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• pp.111-120
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• 2015

Dendritic cells (DCs) play a significant role in establishing self-tolerance through their ability to present self-antigens to developing T cells in the thymus. DCs are predominantly localized in the medullary region of thymus and present a broad range of self-antigens, which include tissue-restricted antigens expressed and transferred from medullary thymic epithelial cells, circulating antigens directly captured by thymic DCs through coticomedullary junction blood vessels, and peripheral tissue antigens captured and transported by peripheral tissue DCs homing to the thymus. When antigen-presenting DCs make a high affinity interaction with antigen-specific thymocytes, this interaction drives the interacting thymocytes to death, a process often referred to as negative selection, which fundamentally blocks the self-reactive thymocytes from differentiating into mature T cells. Alternatively, the interacting thymocytes differentiate into the regulatory T (Treg) cells, a distinct T cell subset with potent immune suppressive activities. The specific mechanisms by which thymic DCs differentiate Treg cells have been proposed by several laboratories. Here, we review the literatures that elucidate the contribution of thymic DCs to negative selection and Treg cell differentiation, and discusses its potential mechanisms and future directions.

• Journal of radiological science and technology
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• v.13 no.1
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• pp.29-35
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• 1990

In a attempt to find out the effects of the irradiation on the lymphatic organs of birds, a total of 40 chickens(4 week old) were selected at random and alloted to control and experimental groups. The experiments were irradiated Co-60 ${\gamma}-ray/400$ rads, and then the enzyme histochemical activity of Bursa Fabricious(BF), thymus and spleen and hematological changes were compared with those of controls for 30 days(24 hrs., 5, 10, 20 and 30 days). The results obtained were summarized as follows: 1. The activity of acid phosphatase(ACP) of the reticuloendothelial cells of BF, thymus and spleen and the epithelia of BF of the experiments were increased significantly from the early experimental terms and then returned to the same level of controls through the late experimental terms. 2. The activity of nonspecific esterase(NSE) of the constituent cells with exception of the lymphocytes in BF, thymus and spleen of experiments were increased significantly from the early experimental terms and then returned to the same level of control through the late experimental terms. 3. The lymphocyte percentage, total erythrocytes and homoglobin of the experiments were severely decreased from early experimental terms and then increased to the normal levels of them incontrols.

• Corrosion Science and Technology
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• v.22 no.5
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• pp.314-321
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• 2023

The aim of the present study was to investigate the effect of thymus extract on corrosion inhibition of aluminum 5083 alloy in a 0.1 M NaCl medium prepared using a mixture of ethylene glycol and water using potentiodynamic and electrochemical impedance spectroscopy (EIS) techniques. The potentiodynamic electrochemical technique showed an increase in corrosion inhibition efficiency starting from 49.63% at a concentration of 0.25 g/L to 92.71% at a maximum concentration of 1.25 g/L of the extract. These results were consistent with those obtained via EIS analysis. Spectral characterization of the tested plant extract using the Fourier-transform infrared spectroscopy (FTIR) technique confirmed the presence of organic compounds having different oxygen and aromatic functionalities in the extract that could help enhance the adsorption of these compounds on the aluminum surface. This study reveals possible adsorption isotherm of the thymus extract on the aluminum surface, supporting a Langmuir isotherm for the adsorption of inhibitor molecules on this surface.

• Journal of Ginseng Research
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• v.21 no.3
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• pp.160-168
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• 1997

The present study was carried out to investigate the effects of Panax ginseng saponin extracts on the dexamethasone-induced apoptosis of mouse thymus in vivo and mouse thymocytes in vitro. The saponin fractions of red ginseng (R-SAP) and white ginseng (Wl-SAP) were provided by the Korea Ginseng & Tobacco Research Institute, and the other saponin fraction of white ginseng (W2-SAP) was extracted in our laboratory. 1. The male ICR mice (3~4 wk old; weighing 15$\pm$2 g) were given by each saponin fraction of 5 mg/kg/ day for 4 days, and at one hour after the last treatment, they were injected by deuamethasone (5 mg/kg : DX). The mouse thymus was extracted at 6 hours after DX injection, and they were stained with hematoxylin-eosin reagents and an Apop-Tag kit, respectively, and the thymocytes prepared from it were labelled with anti-mouse FITC-anti-CD4 and anti-mouse PE-anti-CD8 and then analyzed by fluorescence activated cell sorter (FACS). DX-induced reduction of thymus weight was significantly attenuated by W2- SAP but was not affected by other saponin fractions. And DX-induced apoptotic death of thymocytes, appeared in the histologic findings of the thymus, was inhibited by the saponin fractions and the order of these inhibitory potencies was R-SAP》W2-SAP>Wl-SAP. However, in respect of T cell receptors, the differentiation of thymocytes seems not to be changed by treatments with DX or/and the saponin fractions. 2. In the primary thymocyte culture, the DX-induced reduction of thymocyte MTT values was rather greater in RPMI 1640 medium of IWc fetal bovine serum (FBS) or horse serum (HS). In addition, the DX-Induced MTT reduction was significantly inhibited by R-SAP or W2-SAP, in the culture using that medium of 5% FBS or HS. But these saponin fraction did not effected the DX-induced reduction of thymocyte MTT value in primary culture of 10% FBS or 10% HS. These results suggest that R-SAP and some W-SAP fractions may protect thymocyte from stress or glucocorticoisteroid-induced death of them.

• The Journal of Pediatrics of Korean Medicine
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• v.12 no.1
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• pp.211-230
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• 1998

Introduction The effects of Bojungikkitang on the immunosuppression induced by methotrexate in rats were investigated in this experiment. The multiple parameters of immunity assessed in. each rats includes the rate of body weight loss, weight changes in thymus, spleen and axillary lymphnode. The number of lymphocyte and CD4+ T cell count in blood, thymus, spleen and axillary lymphnode were also measured. Methodology Male Sprague-Dawley rats were chosen as an experiment object and were divided into 3 groups by a random selection. Each group consisted 6 rats. The normal group didn't receive any treatment. The control group was administered methotrexate for 4 days. The sample group was administered with both Bojungikkitang and methotrexate for 4 days. The dosage of medication was 2cc/day, 1cc given at 10AM and another 1cc given at 5PM. Results The rate of body weight loss was significantly decreased in the sample group. The weight of thymus was significantly increased in the sample group while the weight of spleen did not show much increase. Blood CD4+ T cell count, thymus lymphocyte count, thymus CD4+ T cell count, spleen lymphocyte count, spleen CD4+ T cell count and axillary lymph node CD4+ T cell count were significantly increased in the sample group while blood lymphocyte count and axillary lymphnode lymphocyte count did not show much increase. Conclusion As one can witness from the above results, administration of Bojungikkitang played potent role in increasing immune system among the rats treated with methotrexate which induces immunosuppression. Overall increase of lymphocyte count and CD4+ T cell count in the sample group with Bojungikkitang effectively proves its ability to boost the immune system.

• Journal of Plant Biotechnology
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• v.31 no.1
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• pp.37-41
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• 2004

In vitro culture system was established to induce multiple shoots of Thymus quinquecostatus Celak. by investigating the effects of cytokinins. Stem explants were cultures on MS medium supplemented with either five drfferent plant growth regulators or their combinations under light or dark condition. The most effective cytokininsource was the combination of BA 1.0mg/L and TDZ 0.1mg/L for producing shoots (6.05$\pm$1.51), zeatin 2.0mg/L and TEZ 0.1mg/L for elongating shoots (3.27$\pm$0.66cm) under the light condition. In addition the most effective cytokinin was 2-ip 2.0mg/L for producing shoots(5.20$\pm$1.81), zeatin 2.0mg/L for elongating shoots(5.64$\pm$1.24cm)under the dark condition. Overall, the average percent for in vitro shooting was greater than 89.58％.

• Applied Microscopy
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• v.27 no.1
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• pp.31-46
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• 1997

Ultrastructure of mouse thymus was evaluated, following the administration of potassium dichromate and mercuric chloride, the heavy metals of evironmental pollutants. Potassium dichromate (20 mg/kg) or mercuric chloride solutions (10 mg/kg) were subcutanously injected to the mice. Six hours, three days and two weeks after the injections, animals were sacrificed. Thymic tissues were fixed in 2.5% glutaraldehyde-1.5% paraformaldehyde solutions. The procedure was followed by the fixation in 1% osmium tetroxide solutions. Washed and dehydrated tissue-blocks were embedded in the araldite mixture. Ultra-thin sections were stained with uranyl acetate-lead citrate solutions. Results observed were as follows: 1. In electron microscopy, cortical population of thymocytes in the thymus of experimental groups were reduced. especially in the outer cortex. Subcapsular cortices of potassium dichromate treated mice were filled with many epithelial reticular cells, whereas the similar area of mercuric chloride-treated mice exhibited large intercellular spaces. 2. In the thymus of mercuric chloride treated group, large intercellular spaces were formed by shrinkage of epithelial reticular cells, and the space was invaded by numerous cytoplasmic projections of macrophages. Thymocytes nuded out from the shrunken cytoplasm of epithelial reticular cells, presented numerous microvilli. 3. In the thymus of potassium dicromate treated group, many activated macrophages and plasma cells migrated into thymic cortices. 4. In the perivascular spaces of thymic cortices of potassium dichromate- and mercuric chloride-treated mice, activated macrophages. plasma cells, collagen fibrils, and flocculent substance of exudated materials were exhibited. From the above findifgs, it was concluded that potassium dichromate or mercuric chloride could disturb the normal differentiation or 'education' of T cells in the thymic cortex. In turn, these heavy metals may hurt the immunological defense mechanism.

• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2309-2317
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• 2009

Depurination, the release of purine bases from nucleic acids by hydrolysis of the N-glycosidic bond, gives rise to alterations of the cell genome. Though cells have evolved mechanisms to repair these lesions, unrepaired apurinic sites have been shown to have two biological consequences: lethality and base substitution errors. 2-Bromopropane (2-BP) is used as an intermediate in the synthesis of pharmaceuticals, dyes, and other organics. In addition, 2-BP has been used as a replacement for chloroflurocarbons and 1,1,1-trichloroethane as a cleaning solvent in electronics industry. However, 2-BP was found to cause reproductive and hematopoietic disorders in local workers exposed to it. Owing to the toxicity of 2-BP, there has been a tendency to use 1-BP as an alternative cleaning solvent to 2-BP. However, 1-BP has also been reported to be neurotoxic in rats. Though $N^7$-guanine adduct of 2-BP has been reported previously, massive depurination of the nucleosides and calf thymus DNA was observed in this study. We incubated the nucleosides (ddG, dG, guanosine, ddA, dA and adenosine) with excess amount 2-BP at the physiological condition (pH 7.4, $37\;{^{\circ}C}$), which were analyzed by HPLC and LC-MS/MS. In addition, the time and dose response relationship of depurination in nucleosides induced by 2-bromopropane at the physiological condition was investigated. Similarly, incubation of calf-thymus DNA with the excess amount 2-BP at the physiological condition was also performed. In addition, the time and dose response relationship of depurination in calf-thymus DNA induced by 2-BP at the physiological condition was investigated. Those results suggest that the toxic effect of 2-BP could be both from the depurination of nucleosides and DNA adduct formation.

• Archives of Pharmacal Research
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• v.9 no.3
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• pp.157-161
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• 1986

Isolated calf thymus nuclei were in vitro methylated with S- adenosy-L-methyl-$^{14}C$ methionine, and the proteins were fractionated according to their solubilities. Histone fraction ($H_{2}SO_{4}$-soluble fraction) contained approximately 60% total radioactivity incorporated, while "residual protein" which was ($H_{2}SO_{4}$-insoluble contained the remaining radio-activity. The "residual protein" was further fractionated into various acidic proteins, which contained very littel of the radioactivity. However, the protein fraction eluted from DEAE-cellulose with 0.5 N NaOH contained the largest amount of radioactivity. This protein was found to be basic in nature by amino analysis.