• Journal of Nutrition and Health
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• v.36 no.2
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• pp.125-132
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• 2003

The present study was attempted to investigate and compare the antioxidant potency of several well-know flavonoids, antioxidant vitamin and commercially available popular beverages. The antioxidant potency was assessed by the effect on reducing oxidative DNA damage of human lymphocytes. Cellular oxidative DNA damage was measured by SCGE (single-cell gel electrophoresis), also known as comet assay. Lymphocytes were pre-treated for 30 minutes with wide ranges of doses of apigenin, kaempferol, luteolin, myricetin, rutin, quercetin, $\alpha$-tocopherol (10,25,50,100,200,500,1000 $\mu$M) ,green tea extract or grape juice (10,50,100,250,500,1000 $\mu$g/mL) followed by a $H_2O$$_2$(100 $\mu$M) treatment for 5 min as an oxidative stimulus. The physiological function of each antioxidant substance on oxidative DNA damage was analyzed as tail moment (tail length $\times$ percentage migrated DNA in tail) and expressed as relative DNA damage score after adjusting by the level of control treatment. Cells treated with $H_2O$$_2$alone (positive control) had an extensive DNA damage compared with cells treated with phosphate buffered saline (PBS, negative control) or pre-treated with all the tested samples. Of all the six flavonoids, quercetin was the most potent antioxidant showing the lowest $ED_{50}$/ of 8.5 $\mu$g/mL (concentration to produce 50% protection of relative DNA damage). The antoxidant potency of individual flavonoids were ranked as follows in a decreasing order; luteolin (18.4 $\mu$g/mL), myricetin (19.0 $\mu$g/mL) , rutin (22.2 $\mu$g/mL) , apigenin (24,3 $\mu$g/mL) , kaempferol (25.5 $\mu$g/mL). The protective effect of $\alpha$-tocopherol was substantially lower (highest $ED_{50}$value of 55.0 $\mu$g/mL) than all the other flavonoids, while the protective effect was highest in green tea and grape juice with low ED5O value of 7.6 and 5.3, respectively. These results suggest that flavonoids, especially quercetin, and natural compounds from food product, green tea and grape juice, produced powerful anti-oxidative activities, even stronger than $\alpha$-tocopherol. Taken together, supplementation of antioxidants to lymphocytes followed by oxidative stimulus inhibited damage to cellular DNA, supporting a protective effect against oxidative damage induced by reactive oxygen species.

• Macromolecular Research
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• v.13 no.3
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• pp.167-175
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• 2005

This review explores recent works involving the use of the self-assembled nanoparticles of bile acid-modified glycol chitosans (BGCs) as a new drug carrier for cancer therapy. BGC nanoparticles were produced by chemically grafting different bile acids through the use of l-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC). The precise control of the size, structure, and hydrophobicity of the various BGC nanoparticles could be achieved by grafting different amounts of bile acids. The BGC nanoparticles so produced formed nanoparticles ranging in size from 210 to 850 nm in phosphate-buffered saline (PBS, pH=7.4), which exhibited substantially lower critical aggregation concentrations (0.038-0.260 mg/mL) than those of other low-molecular-weight surfactants, indicating that they possess high thermodynamic stability. The SOC nanoparticles could encapsulate small molecular peptides and hydrophobic anticancer drugs with a high loading efficiency and release them in a sustained manner. This review also highlights the biodistribution of the BGC nanoparticles, in order to demonstrate their accumulation in the tumor tissue, by utilizing the enhanced permeability and retention (EPR) effect. The different approaches used to optimize the delivery of drugs to treat cancer are also described in the last section.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.82-91
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• 2020

Recently, the research and development of weapon systems have expanded from ILS centered on acquisition costs to LCS, including operating maintenance costs. Regulations define the provision and formula of operating maintenance costs, but this does not consider the characteristics of the design and operation/maintenance of real weapon systems based on engineering calculations. Therefore, this study suggests a simulation design method to complement these areas and produce more accurate operating maintenance costs. The research procedures are as follows. First, the provision and formula of operating maintenance costs were defined to make the simulation results applicable. Second, a simulation model was developed by reviewing design considerations so that the simulation results reflect reality more accurately. The design considerations include the PBS of weapon systems, operation schedules, specifications for operation/maintenance/warehouse facilities, and basic cost information (personnel expense and spare part/equipment cost). This study is expected to be effective in calculating the operating maintenance costs more easily and accurately.

• Journal of Periodontal and Implant Science
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• v.32 no.3
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• pp.665-683
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• 2002

A novel glucanhydrolase from a mutant of Lipomyces starkeyi KSM 22 has additional amylase activity besides mutanolytic activity and has been suggested as promising anti-plaque agent. It has been shown effective in hydrolysis of mutan, reduction of mutan formation by Streptococcus mutans and removal pre-formed sucrose-dependent adherent microbial film and has been strongly bound to hydroxyapatitie. These in vitro properties of Lipomyces starkeyi KSM 22 glucanhydrolase are desirable for its application as a dental plaque control agent. In human experimental gingivitis　model and 6 month clinical trial, mouthrinsing with Lipomyces　starkeyi KSM 22 dextranase was comparable to 0.12% chlorhexidine mouthwash in inhibition of plaque accumulation and gingival inflammation and local side effect was negligible. This study was aimed to evaluate the cytotoxic effect of Lipomyces starkeyi KSM 22 glucanhydrolase on human gingival fibroblasts. Primary culture of human gingival fibroblasts at the 4th to 6th passages were used. Glucanhydrolase solution was made from lyophilized glucanhydrolase powder from a mutant of Lipomyces stakeyi KSM 22 solved in PBS and added to DMEM medium to the final concentration of 0.5, 1, and 2 unit. Cells were exposed to glucanhydrolase solution or 0.1 % chlorhexidine and the cells cultured in DMEM with 10% FBS and 1% antibiotics as control. After exposure, the morphological change, cell attachment, and cell activity by MTT assay were evaluated in 0.5, 1.5, 3, 6, 24 hours after treatment. The cell proliferation and cell activity was also evaluated at 2 and 7 days after 1 minute exposure, twice a day. The cell morphology was similar between the Lipomyces smkeyi KSM 22 glucanhydrolase groups and control group during the incubation periods, while most fibroblasts remained as round cell regardless of incubation time in the chlorhexidine group. The numbers of the attached cells in the glucanhydrolase groups were comparable to that of control and significantly higher than the chlorhexidine group. The numbers of the proliferated cells in the glucanhydrolase groups at 7 days of incubation were comparable to the control group and higher than the chlorhexidine group. The cell activity in glucanhydrolase groups paralleled with the increased cell number by attachment and proliferation. According to these results, Lipomyces starkeyj KSM 22 glucanhydrolase has little harmful effect on attachment and proliferation of human gingival fibroblasts, in contrast to 0.1% chlorhexidine which was cytotoxic to human gingival fibroblasts. Therefore this glucanhydrolase preparation is considered as a safe and promising agent for new mouthwash formula in the near future.

• Korean Journal of Animal Reproduction
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• v.18 no.1
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• pp.55-62
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• 1994

This study was carried out to test the effects of fluorescein diacetate(FDA 0${mu}ell$/ml, 0.5${mu}ell$/ml, 5${mu}ell$/ml, 10${mu}ell$/ml or 0${mu}ell$/ml, 5${mu}ell$/ml in PBS) treated before culture on the survival of vitrified mouse morulae in vitrification solution(20% glycerol＋glycerol＋10% ethylene glycol＋30% ficoll＋10% sucrose). The results were summarized as follows; 1. The survival rate of FDA-tested fresh mouse morulae after 24 hours culture was over 96%((P4.8) in the control or treatment groups with various levels of FDA. Because the rate of mouse morulae which developed to hatched blastocysts was higher with the various levels of FDA treatment(67%) than control(50%), it was considered that toxicity of FDA did not affect the survival of mouse morulae. 2. When mouse morulae were FDA-tested in FDA 0(control), 0.5, 5, and 10${mu}ell$/ml treatment after vitrification, the development rate to expanded blastocyst were 66, 82, 64 and 76%, and FDA scores were P4.2(84%), P4.7(94%), P4.2(84%) and P3.9(78%), respectively. There were no significant differences between control and FDA treatments, but there were significant difference between 0.5${mu}ell$/ml)94%) and 10${mu}ell$/ml(78%) treatment(P<0.01). 3. The survival rates of cultured mouse morulae according to FDA-scores(P0=non-fluorescence; P1~P5=according to their fluorescence) after vitrification were P5;92%, P4;67%, P3;42% and P2.P0;0%, respectively. 4. Implantation rates of morulae stage embryos cultured into early blastocysts and implanted into uterine hornes vitrification were 14 and 11% embryos treated control(0${mu}ell$/ml) and FDA 5${mu}ell$/ml and the normal fetus development was 2% embryos for both treatments. Results of this percent study indicated that toxicity of FDA does not affect not only the survival of fresh and vitrified mouse morulae but also the development rate and implantation of fetus after transfer as well. The development rates of mouse morulae with the FDA score of P5, P4 and P3 were 92, 67 and 42%, respectively, it was considered that FDA-test was fit for the judge of survival.

• Korean Journal of Animal Reproduction
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• v.18 no.1
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• pp.39-46
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• 1994

This experiment was carried out to develop an in vitro culture system for rabbit embryos. The zygotes or 2-cell embryos were collected from the oviducts of the superovulated and mated does with D-PBS/10% FCS at 24 hours after hCG injection. The in vitro developmental rate of blastocyst formation and the number of nuclei in the embryos were examined under the following treatments; 1) TCM-199 with 10% FCS, 2) EBSS with 10% FCS, 3) rabbit vitreous humor(VH), 4) TCM-199 with 10% FCS＋BOEC, 5) TCM-199 with 10% FCS＋ROEC, 6) EBSS with 10% FCS＋BOEC and 7) EBSS with 10% FCS＋ROEC. For a comparative study of in vivo and in vitro development, the fresh blastocysts, which were developed in vivo for 96 hours after hCG injection, were collected from the uterus and their numbers of nuclei were counted. 1. The zygotes or 2-cell embryos developed to the blastocyst stage in TCM-199, EBSS and VH at the rates of 93, 92 and 89%, respectively. 2. The higher developmental rates 95~98% of blastocyst formation was achieved when the embryos were co-cultured with a monolayer of bovine or rabbit oviductal epithelial cells in TCM-199 or EBSS. No significant difference in developmental rates was shown between bovine and rabbit oviductal epithelial cells. 3. In a comparative study of in vivo and in vitro development, the total numbers of nuclei were significantly less in the in vitro cultured embryos(104~224) than the in vivo developed embryos(1, 0090 at 96 hours after hCG injectin. 4. The mean cell cycle numbers in the embryos cultured for 72 hours in TCM-199 with 10% FCS, EBSS with 10% FCS, TCM-199 with 10% FCS＋BOEC, TCM-199 with 10% FCS＋ROEC, EBSS with 10% FCS＋BOEC and in vivo was 7.38, 6.63, 7.76, 7.69, 7.01 and 9.92, respectively. From these results, it can be suggested the optimal culture system for in vitro culture of rabbit embryos is a co-culture system with bovine or rabbit oviductal epithelial cells in TCM-199 with 10% FCS. Considering the significant reduction in total numbers of nuclei in the in vitro cultured embryos, the advanced research on development of in vitro culture system for rabbit embryos is expected.

• Research in Plant Disease
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• v.17 no.1
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• pp.90-94
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• 2011

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a very serious disease in rice growing regions of the world. There are no effective ways of protecting rice from the disease. In this study, the bacteriophage (phage) mixtures infecting Xoo were investigated as biological control agent on BLB. The effects of pH, heat and ultraviolet on the stability of phages were investigated to check and increase the possibility of practical use in the field. Phages were rather stable between pH 5 and pH 10. The infectivity dropped sharply when the phages were incubated at $50^{\circ}C$ and more than 90% of the phages were inactivated after two minutes of ultraviolet treatment. The phages were stable for 7 days at the rice plant leaves, and the phages survived 10 times more than other treatments when mixed with skim milk. Although the skim milk increased the stability of the phages, the control efficacy was not effective. However, the phage mixtures reduced the occurrence of BLB when they were treated with Tecloftalam WP or Acibenzolar-S-methyl simultaneously. The results indicated that the Xoo phages could be used as an alternative control method to increase the control efficacy and reduce the use of agrochemicals.

• Journal of Life Science
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• v.19 no.6
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• pp.728-734
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• 2009

In this work, a simple, inexpensive and reproducible technique of flotation density gradient centrifugation was developed to isolate monocytes with high purity and yield from peripheral blood mononuclear cells (PBMC) using Histopaque solution, density and osmolarity of which were modified to 1.072 g/ml and 335 mOsm with phosphate-buffered saline (PBS) and sodium chloride (NaCl) solution, respectively. The average purity of monocytes was 74.75${\pm}$3.84%, with the individual purity ranging from 71.44% to 82.38%. The average yield of monocytes was 32.62${\pm}$11.16%, with the individual yields ranging from 21.02 to 53.63%. The monocytes isolated by floatation density gradient centrifugation could be successfully cultured into morphologically, phenotypically and functionally dendritic cells in vitro. In conclusion, the entire procedure seemed to be faster and more convenient, simple and cost-effective than other monocyte isolation methods, including plastic adherence and density gradient methods, and has the potential to be developed as a closed system for clinical scale generation of dendritic cells.

• Journal of Embryo Transfer
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• v.15 no.1
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• pp.67-75
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• 2000

This study was conducted to establish the optimal conditions for in vitro embryo production using oocytes derived from follicles of slaughter-house ovaries. The ovaries of Hanwoo were obtained from a local slaughter-house. The oocytes were aspirated from visible follicles of 2~7mm in diameter. The recovered oocytes which were completely surrounded by at least 2 layers of cumulus cells and a homogeneous cytoplasmic pigmentation were used. The selected oocytes were washed 3 or 4 times with D-PBS containing 10% bovine calf serum (BCS) and matured in vitor (IVM) in Ham's F-10 supplemented with 10% BCS or 0.01 $\mu\textrm{g}$/ml epidermal growth factor(EGF) at 39$^{\circ}C$ under 5% CO2 in air for 24 hours. They were fertilizqed in vitro (IVF) with fresh sperm separated by Percoll density gradient or swim-up in TALP media. The zygotes were cultrued with or without bovine oviductal epitherial cells(BOEC) in media(HECM-6 supplemented with 11 amino acid and / or TCM-199 supplemented with 10% BCS) for 7 to 10 days. The results obtained were as follow: The cleavage rate and developmental rate to blastocyst after maturation and IVF were not significantly different between Ham's F-10 with EGF(76.0% vs. 44.0%) and BCS(75.9% vs. 43.6%)(P<0.05). The cleavage rate and development rate to blastocyst after fertilizing by swim-up or Percoll method were not signifciantly(P<0.05) different between swim-up (80.2% vs. 29.2%) and Percoll(81.9% vs. 26.5%) (P<0.05). The cleavage rate in TCM 199(80.5) was signficiantly higher than that in HECM-6 (72.0%) (P<0.05). However, developmental rate to blastocyst using TCM 199 following HECM-6 for 3 or 4 days (42.2%) was significantly higher than that in TCM-199 alone(26.7%)(P<0.05). The cleavage rate and development rate of embryos produced in vitro by exchange timing for HECM-6 media were not significantly different between in day 3(78.6% vs. 45.5%) and day 4(75.0% vs. 43.2%)(P<0.05). The cleavage rate and developmental rate to blastocysts according to co-culture system were not significantly different between with (74.2% vs. 41.4%) and without BOEC(73.95 vs. 43.5%) (P<0.05). The number of blastomere in blastocyst stage after co-culture with or without BOEC was not significantly different (106.7$\pm$5.1 and 96.6$\pm$4.0). In conclusion, the most transferable IVP embryos could be produced from Ham's F-10 medium for IVM, Percoll density gradient method for IVF sperm separation and in vitro culture in HECM-6 until day 3 or day 4, and then transferred into TCM-199 until day 9 within adequate embryo density in culture droplets after insemination.

• Korean Journal of Microbiology
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• v.40 no.3
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• pp.237-243
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• 2004

The aim of this study is to investigate the detection rate of putative periodontopathogens, Porphyromonas gingivalis, Tannerella forsythia, and Actiobacillus actinomycetemcomitans, related to cardiovascular diseases(CVD). Plaques were sampled from 15 subjects (4 sites of denture base and/or tooth) with sterilized explorers and were transported in IX PBS. The detection of periodontopathogens was performed by polymerase chain reaction with species-specific primers based on 16S rDNA. The PCR products were cloned into pGEM-T easy vector and its nucleotides were sequenced in order to confirm the specificity. Our data showed that the detection rate of P. gingivalis and T forsythia in denture base of edentulous patients was 25％ and 75％, respectively. And the detection rate of P. gingivalis and T.forsythia in denture base of patient having one more tooth was 91％. The results indicate that plaque of denture base may serve as reservoirs of oral bacteria related to CVD.