• 미생물학회지
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• 제40권4호
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• pp.364-366
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• 2004

본 연구는 차 카테킨인 EGCG (epigallocatechin gallate)에 의한 구강세균의 살균효과를 조사하기 위하여 수행되었다. 초기 세포밀도 $10^{7}$ cell/ml의 대상 세균에 대한 항세균 활성은 EGCG 1ml당 5mg에서 조사하였다. 선택 또는 복합배지상에서 집락생성단위(colony-forming unit, CFU)에 근거하여 EGCG의 항세균 활성은 농도에 비례하는 것을 확인하였다. Streptococcus mutans와 Streptococcus sobrinus는 5mg/ml의 EGCG에서 8시간 이내에 완전히 살균되었다. Lactobacillus acidophilus와 Lactobacillus plantarum도 동일한 조건에서 각각 2시간과 4시간 이내에 살균되었다. 2.5 mg/ml의 EGCG로 처리한 사람의 타액에서 유래하는 총 구강세균의 생존율을 BHI 고체배지상에서 조사하였으며, 총 구강세균은 10시간 이내에 완전히 살균되었다. MS 고체배지상에서 S. mitis and S. salivarius의 집락은 감소되었으며 배양 12시간 이내에서는 집락은 관찰되지 않았다. 그 결과, EGCG는 입냄새와 치석의 원인이 되는 구강세균을 살균시키고 충치를 예방하는 자연적이며 효과적인 물질임이 입증되었다.

• International Journal of Oral Biology
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• 제30권4호
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• pp.125-130
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• 2005

Thrombin-induced platelet microbicidal proteins (tPMP) are antibacterial proteins released when platelets are stimulated by thrombin. It has been reported that tPMP has antibacterial activity against various bacterial species including causative agents of infective endocarditis. Most of the oral streptococci have resistance to the killing by tPMP and this fact may play an important role as a virulence factor in infective endocarditis. However, the susceptibility and resistance mechanism of oral streptococci for tPMP have not been revealed yet. In this study, the killing mechanism of tPMP for oral streptococci has been investigated. Streptococcus rattus BHT, a susceptible strain, and Streptococcus gordonii DL1, a resistant strain, have been used in this study. tPMP was isolated from platelet after stimulation with thrombin. Cell membrane depolarization was examined with 3,3'-dipropylthiodicarbocyanine iodide ($DiSC_3$), membrane potential-sensitive cyanine dye, by fluorescence spectrophotometry. The permeabilization of cell membrane by tPMP was investigated with propidium iodide (PI) by flow cytometry. tPMP susceptible S. rattus BHT showed the increase of the $DiSC_3$ fluorescence level meaning depolarization of cell membrane and increase of the uptake of PI which means permeabilization of cell membrane. However, tPMP resistant S. gordonii DLI did not show depolarization and permeabilization. These results indicate that the increasing depolarization and permeabilization of oral streptococcal cell membrane are associated with the bactericidal activity of tPMP.

• 약학회지
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• 제55권1호
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• pp.39-44
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• 2011

Many reports indicate that $18{\beta}$-glycyrrhetinic acid ($18{\beta}$-GA) from Glycyrrhizae Radix has anti-inflammatory and immunoregulatory activities, whereas reports regarding anticancer activity of the compound are few. In present study, we investigated antitumor effect of $18{\beta}$-GA on tumor caused by A549 cancer cell in mice. Data resulting from the cytotoxicity assay showed that $18{\beta}$-GA caused killing of A549 cells. $LD_{50}$ values of $18{\beta}$-GA were app. 180 ${\mu}M$ and 80 ${\mu}M$, corresponding to 48 hr- and 72 hr-treatments, displaying that the killing activity was more effective as the $18{\beta}$-GA treatment was prolonged. Based on these data, antitumor effect of $18{\beta}$-GA was tested in nude mice. For induction of the tumor, A549 ($3{\times}10^6$ cells/mouse) was injected subcutaneously into the lateral abdomen of nude mice (Balb/c nu/nu). To determine the antitumor effect, nude mice with tumor were given $18{\beta}$-GA (1 mg/200 ${\mu}l$/mouse) intraperitoneally every three days for four times. Tumor-sizes were measured with a caliper for a period of 24 days. Results showed that the $18{\beta}$-GA treatment reduced the tumor-sizes (P<0.05) as compared with negative control nude mice that received diluent (DPBS). The reduction degree was greater than reduction degree by doxorubicin (60 ${\mu}g$/mouse), and the pattern of reduction was almost sustained during the entire period of the observation. In conclusion, our studies demonstrate that $18{\beta}$-GA has antitumor activity to the A549 cancer cell-caused tumor.

• 한방안이비인후피부과학회지
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• 제28권4호
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• pp.92-110
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• 2015

Objectives : The water extract of Bowon-tang composited with thePanax, AstragalusandGlycyrrhiza Radixhas been traditionally used for treatment of a sickly child and smallpox in oriental medicine. However, little is known about the regulatory effects of Bowon-tang on the production, expression and activity of immune mediators [nitric oxide, prostaglandin E2, inducible nitric oxide synthetase, cyclooxygenase-2], the macrophage activation factor production, the proliferation, subset expression, the killing activity, and the capping in immune cells.Methods : In this study, we investigated the effects of water extracts from Bowon-tang,Panax, AstragalusorGRin mouse immune cells or human Jurkat T cells. Each extract (25-200 ㎍/㎖)perse had no cytotoxic effect in unstimulated macrophages, but concentration-dependently regulated NO and PGE₂production, iNOS expression, and COX-2 activity in mouse peritoneal macrophages with MAF stimulation. These regulatory effects were synergistically increased by their combination (Bowon-tang).Results : The extract of Bowon-tang concentration-dependently regulated T cell proliferation, CD4⁺and CD8⁺expression, and NK killing activity in mouse splenocytes and capping in Jurkat T cells.Conclusions : These results suggest that the water extract of Bowon-tang composited with thePanax, AstragalusandGRmay be useful for therapeutic drugs against a sickly constitution and immune diseases, probably by regulating the production of immune mediators.

• Archives of Pharmacal Research
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• 제16권4호
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• pp.259-264
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• 1993

Three cell lines, CHO, L929 and B16 which are non-tumorigenic and cancer cells, respectively, were first tested for their survival in the presence of radioprotective ginseng protein fraction(GPF0. The influence of three radioprotectors-CPF, cysteamine, and 1-Methyl-2-bis[(2-methylthio)vinyl] quinolinium iodide (MVQI) on DNA repair capacity of UV damaged cells survival test, the GPF showed higher cytotoxicity in L929 and B16 than in CHO cells. However, the degree of cell killing was also investigated by measuring $^3H$-thymidine incorporation of PUVA treated cells. In cell survival test, the GPF showed higher cytotoxicity in L929 and B16 than in CHO cells. However, the degree of cell killing was not high enough to consider it as an antitumorigenic agent. Variable results were obtained in the effects on DNA repair capacity depending on the protectors and cell lines used. In pretreatment, the presence of GPF and MVOI brought about a sinificant increase in the capacity in both CHO and B16 cells. However, in L929, the enhancing effect was not shown. In all three cell lines, cysteamine showed lower repair capacity than control, suggesting the primary damage reduction in stronger enhancing effects in L929 and B16 cells, while it was weaker in CHO cells. Here also cystemine hsowed a very little or no increase in the capacity in all three cell lines. These results demonstrate that GPF has mild cytotoxicity in tumorignic cells and that GPF and MVQI enhance DNA repair capacity of UV damaged cells, whether they are tumorigenic or not. On the other hand, cysteamine shows only damage reduction effect. Celles of different genetic origin seem to give different responses to the modifier and different modifiers may possibly work by different mechanisms.

• Carbon letters
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• 제8권3호
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• pp.184-190
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• 2007

Carbon Nano Tubes could be either metallic or semi-conducting in nature, depending on their diameter. Its photocatalytic behavior has given an impetus to use it as an anti-microbial agent. More than 95% Escherichia coli and Staphylococcus aureus bacteria got killed when exposed to Carbon Nano Tubes for 30 minutes in presence of sunlight. Carbon Nano Tubes are supposed to have smooth surface on to which it accumulates positive charges when exposed to light. The surface that is non illuminated has negative charge. At the cellular level microorganisms produce negative charges on the cell membrane, Therefore damaging effect of multi walled carbon nano tubes (exposed to light) on the microorganisms is possible. In this paper, photo catalytic killing of microbes by multi walled carbon nano tubes is reported. Killing was due to damage in the cell membrane, as seen in SEM micrographs. Moreover biochemical analysis of membrane as well as total cellular proteins by SDS PAGE showed that there was denaturation of membrane proteins as well as total proteins of both the microbes studied. The killed microbes that showed a decrease in number of protein bands (i.e. due to breaking down of proteins) also showed an increase in level of free amino acids in microbes. This further confirmed that proteins got denatured or broken down into shorter units of amino acids. Increased level of free amino acids was recorded in both the microbes treated with multi walled carbon nano tubes and sunlight.

• 대한미생물학회지
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• 제22권2호
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• pp.109-116
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• 1987

As a process to establish an effective preventive measure of V. vulnificus septicemia, bactericidal effect of distilled water against V. vulnificus was studied. When about $2.0{\times}10^7\;CFU/ml$ of V. vulnificus was inoculated in distilled water, a dramatic decrease in the number of viable bacteria by 5 to $6LOG_{10}$ was observed in 5 minutes. Bactericidal kinetic curves could be divided into the first rapid killing phase until 1 minute and the later slow killing phase after then, showing the heterogeneity of the bacterial population inoculated. When V. vulnificus was inoculated in saline solutions having various salinities, significant decrease in the number of viable bacteria was noted only at salinities under 0.2%. The higher was the concentration of NaCl, the greater was the degree of protection against osmotic shock. When glucose, NaCl, $MgCl_2$, and $CaCl_2$ were diluted with deionized water to give same osmolarities and V. vulnificus was inoculated in each of them to compare the bactericidal curves plotted during the first 5 minutes after inoculation, the protection efficiencies were in the order of $MgCl_2>CaCl_2{\gg}NaCl{\gg}glucose$. Above results indicate that treatment(or thorough washing) of contaminated sea animals or other products with distilled water can be used as a preventive measure of V. vulnificus septicemia, and divalent cations can protect V. vulnifcus to osmotic shock with high efficiency.

• Biomaterials and Biomechanics in Bioengineering
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• 제2권3호
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• pp.127-141
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• 2015

Silver-based systems activated by low intensity direct current continue to be investigated as an alternative antimicrobial for infection prophylaxis and treatment. However there has been limited research on the quantitative characterization of the antimicrobial efficacy of such systems. The objective of this study was to develop a semi-mechanistic pharmacokinetic/pharmacodynamic (PK/PD) model providing the quantitative relationship between the critical system parameters and the degree of antimicrobial efficacy. First, time-kill curves were experimentally established for a strain of Staphylococcus aureus in a nutrientrich fluid environment over 48 hours. Based on these curves, a modified PK/PD model was developed with two components: a growing silver-susceptible bacterial population and a depreciating bactericidal process. The test of goodness-of-fit showed that the model was robust and had good predictability ($R^2>0.7$). The model demonstrated that the current intensity was positively correlated to the initial killing rate and the bactericidal fatigue rate of the system while the anode surface area was negatively correlated to the fatigue rate. The model also allowed the determination of the effective range of these two parameters within which the system has significant antimicrobial efficacy. In conclusion, the modified PK/PD model successfully described bacterial growth and killing kinetics when the bacteria were exposed to the electrically activated silver-titanium implant system. This modeling approach as well as the model itself can also potentially contribute to the development of optimal design strategies for other similar antimicrobial systems.

• 인터넷정보학회논문지
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• 제20권4호
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• pp.103-111
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• 2019

인터넷 개인방송 먹방 프로그램이 유행함에 따라, 본 연구는 이를 시청하는 것이 실제 생활에 어떠한 영향을 미치는지 살펴보고자 하였다. 한국 대학생들을 대상으로 설문조사를 실시하였으며, 총 256부를 최종분석에 사용하였다. 그 결과 첫째, 대학생 응답자들의 먹방 시청동기는 시간 보내기, 식도락 추구, 정보추구, 대리충족 추구, 의사사회 상호작용 추구 순으로 나타났다. 둘째, 대리충족 추구, 식도락 추구, 시간 보내기 추구는 인터넷 먹방 프로그램 시청에 긍정적인 영향을 미치는 것으로 나타난 반면, 정보추구와 의사사회 상호작용 추구의 영향력은 나타나지 않았다. 셋째, 인터넷 먹방 프로그램 시청은 시청행복감과 비만인의 부정적 인식에 긍정적인 영향을 미치는 것으로 나타났으며, 배달음식 주문 빈도에는 영향을 미치지 않은 것으로 나타났다. 이러한 연구 결과를 바탕으로 이 연구의 함의 및 한계점, 후속 연구에 대한 제언을 논의하였다.

• Parasites, Hosts and Diseases
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• 제57권1호
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• pp.49-53
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• 2019

Contaminated liver fluke egg in the environment has led to the high prevalence of human opisthorchiasis associated with cholangiocarcinoma in Southeast Asia. To find the effective lessening methods of Opisthorchis viverrini eggs in the contaminated environment, we investigated the temperature conditions for killing of these trematode eggs in vitro. Numerous O. viverrini eggs were obtained in the proximal part of uteri of adult worms from experimental hamsters. Mature eggs with miracidium were allocated by experimental groups (2 control: positive and negative and 4 treatment: 50, 60, 70, and $80^{\circ}C$) with 0.85% saline, and treated by the experimental plan. Eggs in each experimental groups were observed under the confocal microscope after stain with Propidium Iodide (PI) to evaluate the effect of temperatures. Eggs in 70 and $80^{\circ}C$ groups were all killed after over 10 min heated. Majority of eggs in $60^{\circ}C$ (10, 15, and 30 min heated), 70 and $80^{\circ}C$ (5 min heated) groups were inactivated. However in $50^{\circ}C$ group, below half of eggs were to be killed in all time lapse (10, 15 and 30 min). In order to prevent O. viverrini infection and cholangiocarcinoma, direct treatment of sewage by heating at 70 or $80^{\circ}C$ at least 10 min is essential. Therefore, treatment of O. viverrini eggs at a high temperature is a potential method for controlling egg contamination in sewage.