• Molecular & Cellular Toxicology
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• v.2 no.1
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• pp.21-28
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• 2006

Gadolinium chloride ($GdCl_{3}$) was known to block Kupffer cells and generally its toxicity study based on blocking these cells. Therefore, $GdCl_{3}$ frequently used to study toxic mechanisms of hepatotoxicants inducing injury through Kupffer cells. We also tried to investigate the effect of $GdCl_{3}\;on\;CCl_{4}$ toxicity, typical hepatotoxicants. Administration of $GdCl_{3}$ to mice significantly suppressed AST (asparatate amino transferase), ALT (alanine amino transferase) levels which were increased by $CCl_{4}$ treatment. However, $GdCl_{3}$ didn't inhibit the phagocytotic activity of Kupffer cells. Malondialdehyde (MDA) is a good indicator of the degree of lipid peroxidation. In this study, MDA increased by $GdCl_{3}$ administration not by $CCl_{4}$. To understand the toxicity of $GdCl_{3}$, we analyzed global gene expression profile of mice liver after acute $GdCl_{3}$ injection. Four hundred fifty two genes were differentially expressed with more than 2-fold in at least one time point among 3 hr, 6 hr, and 24 hr. Several genes involved in fibrogenesis regulation. Several types of pro-collagens (Col1a2, Col5a2, Col6a3, and Col13a1) and tissue inhibitor of metal-loproteinase1 (TIMP1) were up regulated during all the time points. Genes related to growth factors, chemokines, and oxidative stress, which were known to control fibrogenesis, were significantly changed. In addition, $GdCl_{3}$ induced abnormal regulation between lipid synthesis and degradation related genes. These data will provide the information about influence of $GdCl_{3}$ to hepatotoxicity.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2002.05a
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• pp.14-23
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• 2002

Development of oligodendrocytes and the generation of myelin internodes within the spinal cord depends on regional signals derived from the notochord and axonally derived signals. Neuregulin (NRG)-1, localized in the floor plate as well as in motor and sensory neurons, is necessary for normal oligodendrocyte development. Oligodendrocytes respond to NRGs by activating members of the erbB receptor tyrosine kinase family. Here, we show that erbB2 is not necessary for the early stages of oligodendrocyte precursor development, but is essential for proligodendroblasts to differentiate into galactosylcerebroside-positive (GalC+) oligodendrocytes. In the presence of erbB2, oligodendrocyte development is normal. In the absence of erbB2 (erbB2-/-), however, oligodendrocyte development is halted at the proligodendroblast stage with a >10-fold reduction in the number of GalC+ oligodendrocytes. ErbB2 appears to function in the transition of proligodendroblast to oligodendrocyte by transducing a terminal differentiation signal, since there is no evidence of increased oligodendrocyte death in the absence of erbB2. Furthermore, known survival signals for oligodendrocytes increase oligodendrocyte numbers in the presence of erbB2, but fail to do so in the absence of erbB2. Of the erbB2-/- oligodendrocytes that do differentiate, all fail to ensheath neurites. These data suggest that erbB2 is required for the terminal differentiation of oligodendrocytes and for development of myelin.

• Korean Journal of Poultry Science
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• v.17 no.2
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• pp.79-82
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• 1990

An experiment was conducted to evaluate relative biopotency of tri-iodothyronine ($T_3$) and thyroxine ($T_4$) to induce oxygen consumption in young chicks. Four experimental groups of 3 chicks were injected with $T_3$ or $T_4$ at a dose of 500 or 1000mg per kg body weight, and thereafter oxygen consumption was measured by indirect calorimetry using a respiration apparatus. Oxygen consumption was significantly increased at 2 and 4 hour in the $T_3$ or $T_4$ treated chicks at 500mg at 2 hour. From coefficient of a multiple regression equation of oxygen consumption on $T_3$ or $T_4$, it was concluded that $T_3$ was shown to be two to three times as biologically active as $T_4$.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2001.10b
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• pp.130-130
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• 2001

• Toxicological Research
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• v.7 no.2
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• pp.239-255
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• 1991

Several types of IFNs were tested for their ability to suppress TCDD-inducible P-450 dependent mixed function oxidase (MFO) system in mouse primary hepatocytes. Mouse IFN-gamma (IFN-G) markedly suppressed EROD activity when added at the same time as TCDD (10 nM). The antagonism of EROD activity by IFN-G exhibited both a dose-(10-100 U/ml) and time-depedence. In contrast, mouse IFN-A/B was only moderately suppressive and only at high concentrations (500 U/ml). Rat IFN-G was even more selective than mouse, wherase human IFN-G had no activity.

• Journal of Life Science
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• v.10 no.1
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• pp.45-47
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• 2000

Nonactin, known as an ionophore antibiotic, was antagonized by the actibity of quercetin, an oxygen radical scavenger. This compound generated superoxide radicals in Bacillus subtilis lysates. A recombination-deficient mutant strain of B. subtilis was more sensitive than a wild strain, and this hypersensitivity was reduced in the presence of dithiothreitol as an antioxidant. These results suggest that superoxide radical is important in the antibacterial action of this agent.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.261.3-262
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• 2002

The herbal combination allergina has been used for the treatment of inflammatory diseases in South Korea. In this study. we investigated the immunosuppressive activities of allergina in more detail. Acute graft-versus-host disease (GVHD) is a major cause of morbidity and mortality in patients undergoing allogeneic bone marrow transplantation. (omitted)

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10a
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• pp.130-130
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• 2001

Silymarin, a polyphenolic flavonoid antiodant, has been shown to have anti-inflammatory, hepatoprotective, and anticarcinogenic effects. In the present study, we report the inhibitory effect of silymarin on nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) mRNA expression in macrophages. In vivo administration of silymarin attenuated NO production of peritoneal macrophages in lipopolysaccharide (LPS)-treated mice.(omitted)

• Journal of Life Science
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• v.10 no.2
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• pp.21-26
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• 2000

Cytokine deprivation-induced apoptosis can abrogate by the appropriate survival factors. Because the mechanism of Interleukin (IL)-2 deprived apoptotic cell death remains unclear, we here show the apoptosis in CTLL2 cells correlates with an increase of the activity of caspase3-like protease(s). Inhibition of caspase3-like protease(s) with caspase protease inhibitors (Z-VAD, Z-EVD, and Z-LPD) blocks typical apoptotic morphological abnormalities in CTLL2 cells. Interestingly, Bcl-{TEX}$X_{L}${/TEX} protein was decreased by IL-2 deprivation in the cells. These results suggest that caspase3-like protease(s), not caspase1, plays an important role in apoptosis execution of CTLL2 cell death.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.259.1-259.1
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• 2002

Many polysaccharides isolated from plants are considered to be biological response modifiers and have been shown to enhance various immune responses in vivo and in vitro. Here we demonstrate that a polysaccharide isolated from cell culture of Acanthopanax senticosus (AS) has a unique mode of immunostimulation with regard to its cell-type specificity. AS was found to markedly increase polyclonal IgM antibody production and the proliferation of B cells. and to activate iNOS transcription and NO production in macrophages. (omitted)