• Journal of Periodontal and Implant Science
• /
• v.24 no.2
• /
• pp.238-254
• /
• 1994

Cyclosporine A is an immunosuppressant commonly used for patients receiving organ transplants. Gingival overgrowth is an adverse side-effect seen in about 8-26% of patients taking cyclosporine A which have been shown to increase the DNA synthesis of gingival fibroblast at the concentration of $10^{-9}g/ml$ in vitro. Glycyrrhetinic acid is the active pharmacological ingredients of licorice which exerts steroid-like action and anti-viral activity. Oleanolic acid, which were isolated from Glechoma hederacea, has been shown to act as inhibitors of tumor promotion in vivo and to be less cytotoxic retinoic acid. This study has been performed to evaluate the effects of glycyrrhetinic acid and oleanolic acid on cyclosporine A induced cell activity in vitro. Human gingival fibroblasts were isolated from explant cultures of healthy gingiva of orthodontic patients. Gingival fibroblasts were trypsinized and transferred to the walls of microtest plates. Fibroblasts were cultured in growth medium added $10^{-9}g/ml$ cyclosporineA and $50{\mu}l/ml$ lipopolysaccharides. Cells between the 4th and 6th transfer in culture were used for this study. The morphology of gingival fibroblst were examined by inverted microscope. The effects of cyclosporine A on the time course of DNA sythesis by human gingival fibroblasts were assessed by $[^3H]-thymidine$ uptake assays. Cyclosporine A was found to stimulate DNA synthesis of human gingival fibroblast at a concentration of $10^{-9}g/ml$. In the presence of lipopolysaccharide derived from Fusobacterium nucleatum, addition of cyclosporine A results in reversal of inhibition at the concentration which normally inhibits gingival fibroblast proliferation. The cell acitivities in the presence of glycyrrhetinic acid and oleanolic acid were decreased, and increased cell acitivities by cyclosporine A were decreased by glycyrrhetinic acid and oleanolic acid at the concentration of $200{\mu}g/ml$. These results suggested that the increased cell activities by cyclosporine A modulated by glycyrrhetinic acid and oleanolic acid.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.11 no.4
• /
• pp.299-305
• /
• 2006

Aromatic L-amino acid transaminase is an enzyme that is able to transfer the amino group from L-glutamate to unnatural aromatic ${\alpha}-keto$ acids to generate ${\alpha}-ketoglutarate$ and unnatural aromatic L-amino acids, respectively. Enrichment culture was used to isolate thermophilic Bacillus sp. T30 expressing this enzyme for use in the synthesis of unnatural L-amino acids. The asymmetric syntheses of L-homophenylalanine and L-phenylglycine resulted in conversion yields of >95% and >93% from 150 mM 2-oxo-4-phenylbutyrate and phenylglyoxylate, respectively, using L-glutamate as an amino donor at $60^{\circ}C$. Synthesized L-homophenylalanine and L-phenylglycine were optically pure (>99% enantiomeric excess) and continuously pre-cipitated in the reaction solution due to their low solubility at the given reaction pH. While the solubility of the ${\alpha}-keto$ acid substrates is dependent on temperature, the solubility of the unnatural L-amino acid products is dependent on the reaction pH. As the solubility difference between substrate and product at the given reaction pH is therefore larger at higher temperature, the thermophilic transaminase was successfully used to shift the reaction equilibrium toward rapid product formation.

• Analytical Science and Technology
• /
• v.12 no.6
• /
• pp.498-503
• /
• 1999

Co(II), Ni(II), and Cu(II) complexes with tetradentate schiff base-$NOTDH_2$, were synthesized. The structures of these complexes were characterized by elemental analysis, IR, UV-visible, NMR spectra, and thermogravimetric analysis. The mole ratio of schiff base($NOTDH_2$) to the metal(II) at complexes was found to be 1:1. Cu(II) complexes were four-coordinated configuration, while Co(II) and Ni(II) complexes were hexacoordinated configuration containing two water molecules and all complexes were non-ionic compounds.

• Biomedical Science Letters
• /
• v.11 no.3
• /
• pp.319-326
• /
• 2005

It is well known that oxidative stress of reactive oxygen species (ROS) may be a causative factor in the pathenogenesis of bone disorder on osteoblast or osteoclast. The purpose of this study was to evaluate the cytotoxicity of oxidative stress, protective effect of glutamate receptor antagoinst against ROS-induced osteotoxicity, secretion of tumor necrosis factor $(TNF)-\alpha$ and the expression of c-fos gene in the cultured rat osteoblasts and osteoclasts. Cell viability by MTS assay or !NT assay, activity of glutathione peroxidase (GPx), lipid peroxidation (LPO) activity, protein synthesis by sulforhodamine B (SRB) assay, alkaline phosphatase (ALP) activity, lactate dehydrogenase (LDH) activity, MTS assay for NMDA (N-methyl-D-aspartate) receptor antagonist or AMPA/kainate receptor antagonist, measurement for $TNF-\alpha$, and c-fos gene expression were performed after these cells were treated with or without various cocentrations of xanthine oxidase (XO), hypoxanthine (HX), D-2-amino-5-phosphonovaleric acid (APV), 7-chlorokynurenic acid (CKA), 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and 6,7-dinitroquinoxaline-2,3-dione (DNQX), respectively. In this study, XO/HX showed decreased cell viability and glutathione peroxidase (GPx) activity, but it showed increased LPO activity, $TNF-\alpha$ secretion and c-fos expression. APV and CKA incresed protein sythesis and ALP activity. While, CNQX or DNQX did not show any protective effect in LDH activity or cell viability. From these results, XO/HX showed cytotoxic effect in cultured rat osteoblast or osteoclast, and also NMDA receptor antagonist such as APV or CKA was effective in blocking XO/HX-induced osteotoxicity in these cultures.

• YAKHAK HOEJI
• /
• v.42 no.2
• /
• pp.153-158
• /
• 1998

Calcium hydrogen phosphate was synthesized by reacting calcium chloride and sodium hydrogen phosphate solution in this study. It is well known that the particle size and yield o f calcium hydrogen phosphate produced is greatly affected by the synthetic conditions such as the reactant concentration, reaction temperature, reacting fine, mole ratio and drying temperature, etc. The purpose of this study is to investigate the optimum synthesis condition from the viewpoint of yield and sedimentation volume of the prepared calcium hydrogen phosphate powder according to a randomized complete block design proposed by G.E.P. Box and K.B. Wilson. It was found that the optimum synthetic conditions of calcium hydrogen phosphate were as follows: It was found that optirnum temperature range of reactant solutions was $28-38^{\circ}C$ and $32-42^{\circ}C$ respectively, on the viewpoint of yield and sedimentation volume. The optimum concentration range of reactant solutions was 5.5-10.0% and 6.9-7.4% respectively, on the viewpoint of yield and sedimentation volume. The optimum mole ratio of $CaCl_2$ to $Na_2HPO_4$ was in the range of 1.2-2.0 and the optimum reacting time range was 8.5-11.0 minutes. The optimum drying temperature range was $39-41^{\circ}C$ from the viewpoint of yield, but it was $39-43^{\circ}C$ on the basis of sedimentation volume. Crystallographic analysis to X-ray diffraction patterns of commercially available ecalcium hydrogen phosphate and calcium hydrogen phosphate samples prepared in this study suggested that all samples tested belonged to monoclinic crystal system characteristic of $CaHP0_4{\cdot}2H_20$ crystals.

• Restorative Dentistry and Endodontics
• /
• v.18 no.1
• /
• pp.156-172
• /
• 1993

The purpose of this study was to evaluate for the cytotoxicity of root canal sealers - Tubliseal, N2, AH26, and Sealapex - on fibroblasts cultivated from human periodontal ligament. Succinate dehydrogenase activity test and $^{51}Cr$ release test were performed to evaluate the shortterm cytotoxicity. According to l,3 and 6 days vital cell count and $^{14}C$-leucine incorporation rate to fibroblasts were evaluated. The results of this study were as follows: 1. In the test of SDH activity by millipore filter method, Sealapex showed mild cytotoxicity but Tubliseal, N2 and AH26 showed severe cytotoxicity. 2. In $^{51}Cr$ release test, Tubliseal was the most cytotoxic sealer tested, and rank ordered the relative cytotoxicity of the other sealers tested as follows: AH26, N2, Sealapex. 3. In the test of viable cell count, cytotoxicity in Tubliseal was continued because vital cell number reduced with time. Because vital cell was not showed in N2 and AH26 at 1 day, it was recognized that N2 and AH26 exhibited severe cytotoxicity. In Sealapex, vital cell number increased remarkably with time, so it showed that cytotoxicity decreased with time. 4. In $^{14}C$-leucine incorporation rate test, protein sythesis was not produced in Tubliseal, N2 and AH26 after 3 days, it showed that cytotoxicity in Tubliseal, N2 and AH26 was severe. Although protein synthesis in Sealapex decreased with time, it continued after 6 days. Therefore Sealapex has been exhibited mild cytotoxicity.

• Journal of Environmental Health Sciences
• /
• v.27 no.2
• /
• pp.82-91
• /
• 2001

This study was carried out to elucidate the protective effect of zinc chloride(ZnCl$_2$) and its mechanism against the immuno-cytotoxicity of methylmercury chloide($CH_3$HgCl). This study was observed in the culture of EMT-6 cells which are originated from mammary adenocarcinoma of Balb/c mouse. Cytotoxicity of metals was measured by cell viability and NO$_2$$^{[-10]}$ , and mitochondrial function was evaluated by adenosine triphosohate (ATP) production. $CH_3$HgCl significantly decreased the sythesis of nitric oxide(NO), ATP and glutathione(GSH) in a dose-dependent manner. ZnCl$_2$ significantly increased the synthesis of GSH in a dose-dependent manner, but synthesis of NO and ATP were not changed. The immuno-cytotoxicity of $CH_3$HgCl was not fully protected when combined addition of ZnCl$_2$, whereas ZnCl$_2$ prior to addition of $CH_3$HgCl completly protected the Hg-induced immuno-cytotoxicity. Similarly, intracellular accumulation of mercury significantly decreased by ZnCl$_2$. Degree of diminution of intracellular mercury was larger in ZnCl$_2$ prior to addition of $CH_3$HgCl than in combined addition of ZnCl$_2$ and $CH_3$HgCl.. Dithiothreitol(DTT) or buthionine sulfoximine(BSO) addition at 50$\mu$M or less, which was not toxic to the cells, did not affect synthesis of NO and ATP. DTT increased intracellular GSH level and DTT pretreatment protected toxicity induced by $CH_3$HgCl as shown complete recover in the NO and ATP values. BSO decreased intracellular GSH level and BSO pretreatment exaggerated toxicity induced by $CH_3$HgCl as shown synergistic reduction in the NO and ATP values. These results indicated that the protective effects of zinc against immuno-cytotoxicity of methylmercury associated with increasing cellular level of GSH. Increased intracellular GSH transports methylmercury to out of cells. In accordance with intracellular level of mercury decreased, immuno-cytotoxicity of methylmercury decreased. These result also suggest that the protective mechanism of zinc against the mercury toxicity would be exerted in the immune system in vivo.