Induction of IL-8 and reactive oxygen species in periodontal ligament cells by Aggregatibacter actinomycetemcomitans

PURPOSE: Interleukin (IL)-8 is one of pro-inflammatory cytokines. Reactive oxygen species (ROS) are reduced metabolites of O2. Aggregatibacter actinomycetemcomitans is one of representative periodontopathogens. To investigate the role of A. actinomycetemcomitans in IL-8 expression of periodontal ligament (PDL) cells, we estimated the production of IL-8 and ROS in A. actinomycetemcomitans treated PDL cells. METHODS: The IL-8 production was determined by enzyme-linked immunosorbent assay. The ROS production was estimated using H2DCFDA and FACS. RESULTS: A. actinomycetemcomitans increased the production of IL-8 and ROS at 10, 100, and 500 multiplicity of infection. N-cetylcysteine, an antioxidant of ROS, down-regulated the production of IL-8 induced by A. actinomycetemcomitans. CONCLUSION: These results suggest that A. actinomycetemcomitans induces IL-8 production and ROS may act as a mediator in this process.ope

Induction of IL-6 and IL-8 Expression by Leptin Treatment in Periodontal Ligament Cells and Gingival Fibroblasts

Leptin is one of the adipocytokines produced from adipose tissue but its functions in periodontal tissue have not previously been investigated. In our current study, we examined the effects of leptin on the expression of interleukin (IL)-6 and IL-8 in periodontal ligament (PDL) cells and gingival fibroblasts. Leptin receptor expression was evaluated by RT-PCR and the production of cytokines was measured by ELISA. The phosphorylation of Akt and Erk1/2 was assessed by western blotting. mRNA of long and short form leptin receptors were detected in both PDL cells and gingival fibroblasts. Leptin was found to increase the production of IL-6 and IL-8 in both of these cell types, an effect which was not blocked by polymyxin B, an inhibitor of lipopolysaccharide (LPS). Leptin did not alter the production of IL-6 and IL-8 induced by LPS in PDL cells but increased Akt and Erk1/2 phosphorylation in these cells. These results suggest that leptin acts as an inducer of IL-6 and IL-8 in PDL cells and gingival fibroblasts.ope

外換市場의 非線型 動態的 特性에 관한 硏究 : 카오스 模型과 條件附 二分散模型을 中心으로

학위논문(석사)--서울大學校 大學院 :經營學科 經營學專攻,1997.Maste

Internet search industry : Googles strategic choice to penetrate into Korean market

Thesis(masters) --서울대학교 대학원 :경영학과(SNU Global MBA), 2009.8.Maste

競爭法上 自律遵守프로그램의 導入과 課題

학위논문(석사)--서울대학교 대학원 :법학과,2005.Maste

Analysis of the dialogue of Plato: Euthydemos

Sociates narlates to Crito a remailtable scene in which he has himself talcell -pait, and 111 which the two blotheis, Dionysodoros and Euthydemos, are the chief pelformers. They have accomplished a remarkable art, that is, the art of eristic or fighting with wolds, originated from Eleatic philosophy. They declare that they can also teach virtue in a very shott time and in the best manner. Sociates lsdesirous that the youth Kleinlas should have the benefit of their instructioiis. They decide to tea& on the condition that the young man should be willing to answer qu$stions. The instluction or the exhortation to virtue begins. "Are those who learn, the wise or the ignorant?" says Euthydemos. "The wlse," is the reply, But in the process of dialogue, Kleinias comes to agree that when one learned, one did not know and was not wise." Next, Dionysodoros' attack begins: "Who are they who learn the dictation of the grammar- master; the learned boys or the unleained boys?" "The leained," is the reply. "Then your last answer to Euthydemos was wrong," says Dionysodoros. They simply seem to use amphibology, but at a deeper level, there lies their unique philosophy. Socrates, perceiving that the two strangers are not serious, is desirous of showing the way in which the exhortation to virtue should be carried on. I-Ie argues that all men desire good; that the knowledge and wisdom are the only good, and ignolance and folly the only evil; and that wealth, health, beauty, etc., being in themselves neither good nor evil, become good only through knowledge and wisdom, alld bring happiness. The conclusion is that one must seaich after 'wisdom', and become a philosopher, or lover of wisdom. "Certai~lly I will do my best," says ICleinias. The tw70 brothels recommence their own exhortation, svhlch is of quite another sort. They aslied Socrates. "Do you want ICleinias to be wise?" "Yes." "Is he now wise?" "No." "Then you want him to be what he is not, that is, to perish!" Here, Ictesippus, the lover of Icleinias, interposes in great excitement. Quickly entangled in the meshes of their sophistry, he finds that for them there are no contradlction, no error, no ignorance, no falsehood. ICtesippus brealcs out. But, pacifying him, Socrates renews the conversation with Icleinias. 140 Their conversation begins at the point they left off. The point is, as described above, the conclusion that Kleinias must become a philosopher. Philosophy is the possession of knowledge, which must do us good and makes us happy. What knowledge is there which has such a nature? Kleinias and Socrates are described as wandering about in a wilderness, vainly searching after the art of life and happiness. At last they met with the kingly art. But ~t only gives them the most hard question. SO in despair Kleinias and Socrates request the two heroes' aid. Euthydemos argues as follows: someone cannot know and not know; so, Socrates who knows something, cannot know some things and not know others; therefore Socrates knows all. A similar play of words follows. At last, ironically Socrates and Kleinias confess that the two heroes are invincible

Lee Eon-jeok and the Politics of Zhong (中)

이언적(李彦迪: 1491~1553)은 사화가 연달아 벌어지던 16세기 초 조선에서 중앙정치의 정상화를 모색하였던 인물이다. 특히, 명종 즉위년(1545) 벌어진 을사사화의 파국 속에서 이언적은 신중한 자세로 최대한 피화의 범위를 축소하고 권신의 독주를 막으려 하였다. 본 논문에서는 이 시기 이언적의 행위를 설명하기 위하여 그의 저작 『대학장구보유』(大學章句補遺)를 살펴보고자 한다. 이 책에서 등장하는 주요개념인 중(中)과 본말은 이 시기 이언적의 문제의식, 구체적 대응방식과 연관된다 할 수 있으며, 이러한 연관관계는 선조(宣祖) 때 벌어진 문묘종사 논쟁에서 영남 유생들에 의해 다시 언급되기도 하였다. 정치적 파국이 거듭되었던 16세기 초의 조선의 정국 속에서 진실로 그 중(中)을 잡아(允執厥中) 정국의 평형을 유지하였고, 신중하게 당대 정치의 핵심과제인 중앙정치의 정상화를 모색하였던 이언적은 문묘종사를 통해 후대인들에게 하나의 모범적인 정치가 상으로 자리잡았다. 정치적 갈등의 양상이 나날이 복잡해져가는 대한민국의 상황속에서 이언적의 정치가 상을 복기하는 작업은 오늘날에도 유의미한 일이 될 것이다.Lee Eon-jeok (李彦迪: 1491-1553) is a scholar and statesman who tried to settle the Joseon Dynastys political instability in the 16th century. This instability was mainly caused by a series of literati purges. When the last purge, Ulsa Sahwa (乙巳士禍), occurred in 1545, Lee attempted to reduce the scale of the calamity and prevent Yoon Won-hyungs group―which persecuted other political groups to take power―from monopolizing political authority. In this paper, Daehak jangguboyu (大學章句補遺), one of Lees books, will be analyzed to explain his behavior in 1545. The concepts of Jung (中) and Bonmal (本末), which are emphasized in Daehak jangguboyu, properly represent his awareness of the political situation of the time and the discreet manner in which he reacted to Yoons group. More than 50 years later, the literati from Yeongnam region also used the terms Jung (中) and Bonmal (本末) to clarify Lees intentions and behavior in 1545. Lee strove to stabilize the Joseon Dynastys politics, while prudently minimizing damages from constant purges under intricate and harsh circumstances in 1545. As a result, Lee became one of the most revered Confucian scholars and an ideal statesman of the times. Remembering Lees political thought and behavior also gives meaningful lessons in todays era of complicated political circumstances