담배 니코틴에 의한 사람 태아 성상세포에서 종양괴사인자(TNF-α)의 발현 억제작용

손일홍,이성익,양현덕,한선정,석승한,이재규,김재현,박주영,문형인,이성수,Son, Il-Hong,Lee, Sung-Ik,Yang, Hyun-Duk,Han, Sun-Jung,Suk, Seung-Han,Lee, Jai-Kyoo,Kim, Jae-Hyun,Park, Joo-Young,Moon, Hyung-In,Lee, Sung-Soo 대한화학회 2007 대한화학회지 Vol.51 No.3

니코틴은 사람 대식세포에서 interleukin 2 (IL-2)와 종양괴사인자 (tumor necrosis factor-alpha; TNF-α) 가 생성되는 것을 억제하는데, 이러한 억제작용은 cytokine 유전자 발현 중 전사단계에서 전사인자의 활성을 억제함으로써 일어난다. 이러한 니코틴의 면역반응 억제작용은 아프타성궤양 및 궤양성대장염, 알레르기성폐 포염, 건초열 등에서도 보고되고 있다. 만일 중추신경계에서도 위와 같은 니코틴의 면역억제 작용이 일어난 다면 다발성경화증과 같은 면역반응 매개질환의 치료에 새로운 전기가 마련될 수 있을 것이다. 본 연구에서 는 중추신경계의 여러 면역반응 매개질환의 병태생리에 대한 이해를 넓히고자, 이미 알려진 니코틴의 cytokine 생성억제가 사람 중추신경계의 성상세포에서도 일어남을 확인하고 그 억제기전을 밝히고자 하였다. 이를 위 하여 사람 태아 성상세포에 다양한 농도의 니코틴과 IL-1β를 처리한 다음 TNF-α mRNA의 발현 정도와 NF- κB의 활성을 비교, 분석하여 다음과 같은 결과를 얻었다. 1. 사람 태아 성상세포를 0.1-20 μg/ml의 니코틴으로 처리해 본 결과 10 μg/ml 이상의 농도에서 세포독성능이 나타나기 시작하였다. 2. 사람 태아 성상세포에 IL- 1β를 처리하면 2시간만에 TNF-α mRNA가 최대로 발현되었으며 그 이후로는 점진적으로 감소하였다. 3. 사 람 태아 성상세포를 1 및 0.1 μg/ml의 니코틴으로 전처리한 후 IL-1β로 자극한 군에서는 IL-1β 단독 처리군에 비해 TNF-α mRNA의 발현이 감소하는 양상을 보였다. 1 μg/ml의 니코틴을 처리한 경우에는 8시간 이후부터 TNF-α mRNA의 발현이 현저하게 감소하여 12시간에 최대로 감소하였다. 또한 0.1 μg/ml의 니코틴을 처리한 군에서는 24시간에 가장 현저하게 감소하였다. 4. 성상세포에 IL-1β로 처리한 군에서는 강력한 NF-κB의 활성 을 확인할 수 있었으며, 니코틴을 전처리하고 IL-1β 자극한 군에서는 NF-B의 활성이 감소하였다. 결론적으로 일정농도 이상의 니코틴은 세포독성효과를 나타내나 적정한 농도와 시간 경과후 니코틴은 사람 태아 성상세포에서 IL-1β에 의해 유도되는 TNF-α의 발현 감소를 유도하며, 이는 NF-κB의 활성을 감소시킴으로써 나타난다고 생각된다. The Tumor necrosis factor-α, (TNF-α), is involved in the pathogenesis of multiple sclerosis and contributes to the degeneration of oligodendrocytes as well as neurons. Nicotine has been found to have immunosuppressive and inflammation-suppressing effects. Astrocytes, the major glial cells in the CNS, are capable of producing TNF-α at both the mRNA and protein levels in response to interleukin-1 (IL-1) or TNF-α. Nicotine has been shown to influence glial cell functions. To order to explore the role of astrocytes in the production of TNF-α, astrocytes were pretreated with nicotine and are stimulated with IL-1β to determine their effects on TNF-α production. The results are as follows. Cytotoxic effects of nicotine on human fetal astrocytes were noted above 10 μg/ml of nicotine. The effect of IL-1β on TNF-α mRNA expression in primary cultured human fetal astrocytes was maximal at 2 h after IL- 1β(100 pg/ml) treatment. Human fetal astrocytes were pretreated with 0.1, 1, and 10 μg/ml of nicotine and then stimulated with IL-1β (100 pg/ml) for 2 h. The inhibitory effect of nicotine on expressions of TNF-α mRNA in human fetal astrocytes with pretreated 0.1 μg/ml of nicotine is first noted at 8 hr, and the inhibitory effect is maximal at 12 h. The inhibitory effect at 1 μg/ml of nicotine is inhibited maximal at 24 h. Nicotine at 0.1, 1 and 10 μg/ml concentrations significantly inhibits IL-1β-induced NF-κB activation. Collectively, this study indicates that nicotine might inhibit the expression of TNF-α in activated human fetal astrocytes.

표적세포의 Nitric oxide 합성이 LAK 세포의 세포독성에 대한 예민도에 미치는 영향

박성일,박주형,이치국,김신재,최보금,곽재용,임창열,Park, Sung Il,Park, Ju Hyung,Lee, Chi Kug,Kim, Shin Chae,Choi, Bo Geum,Kwak, Jae Yong,Yim, Chang Yeol 대한면역학회 2001 Immune Network Vol.1 No.2

Background: Nitric oxide (NO), a cytotoxic molecule is produced in various tissues including tumor cells during interleukin-2 (IL-2) therapy . Lymphokine-activated killer (LAK) cells are induced during IL-2 therapy, and have cytotoxic activity against tumor cells. The current study investigated the effects of NO synthesized in target cells or exposure of target cells to NO on the sensitivity of target cells to LAK cell cytotoxicity. Methods: Cytotoxicity was measured using 4 h chromium release assays. LAK cells which were induced by a 4 day incubation of BALB/c mouse splenocytes with IL-2 (6,000 IU/mL) were employed as effector cells. RD-995 skin tumor cells originated from a C3H/HeN mouse were employed as target cells. NO synthesis in target cells was induced by a 24 h incubation of RD-995 cells with $IFN{\gamma}$ (25 U/mL), TNF (50 U/mL) and IL-1 (20 U/mL). S-nitrosyl acetylpenicillamine (SNAP), an NO donor, was used to expose target cells to NO. $N^G$-monomethyl-L-arginine (MLA) and carboxy-PTIO were added during cytotoxicity assays to inhibit NO synthesis, and to scavenge NO produced by target cells, respectively. Results: Sensitivity of NO-producing RD-995 cells to LAK cell cytotoxicity was decreased by addition of MLA and carboxy-PTIO during cytotoxicity assays. However, the two reagents had no effect on the sensitivity of non-NO-producing RD-995 cells. Pretreatment of RD-995 target cells with SNAP increased the sensitivity in comparison with untreated cells. Conclusions: Sensitivity of target cells to LAK cell cytotoxicity is increased by target cell NO synthesis or exposure to NO. Further studies are needed to evaluate whether these in vitro results have relevance to in vivo phenomena.

Nicotine Suppresses TNF-${\alpha}$ Expression in Human Fetal Astrocyte through the Modulation of Nuclear Factor-${\kappa}B$ Activation

Son, Il-Hong,Park, Yong-Hoon,Yang, Hyun-Duk,Lee, Sung-Ik,Han, Sun-Jung,Lee, Jai-Kyoo,Ha, Dae-Ho,Kang, Hyung-Won,Park, Joo-Young,Lee, Sung-Soo The Korean Society of Toxicogenomics and Toxicopro 2008 Molecular & cellular toxicology Vol.4 No.2

Parkinson's disease (PD) progresses severely by a gradual loss of dopaminergic neurons in the substantia nigra (SN). Epidemiological studies showed that the incidences of PD were reduced by smoking of which the major component, nicotine might be neuroprotective. But the function of nicotine, which might suppress the incidences of PD, is still unknown. Fortunately, recently it was reported that a glial reaction and inflammatory processes might participate in a selective loss of dopaminergic neurons in the SN. The levels of tumour necrosis factor (TNF)-${\alpha}$ synthesised by astrocytes and microglia are elevated in striatum and cerebrospinal fluid (CSF) in PD. TNF-${\alpha}$ kills the cultured dopaminergic neurons through the apoptosis mechanism. TNF-${\alpha}$ release from glial cells may mediate progression of nigral degeneration in PD. Nicotine pretreatment considerably decreases microglial activation with significant reduction of TNF-${\alpha}$ mRNA expression and TNF-${\alpha}$ release induced by lipopholysaccharide (LPS) stimulation. Thus, this study was intended to explore the role of nicotine pretreatment to inhibit the expressions of TNF-${\alpha}$ mRNA in human fetal astrocytes (HFA) stimulated with IL-$1{\beta}$. The results are as follows: HFA were pretreated with 0.1, 1, and $10{\mu}g/mL$ of nicotine and then stimulated with IL-$1{\beta}$ (100 pg/mL) for 2h. The inhibitory effect of nicotine on expressions of TNF-${\alpha}$ mRNA in HFA with pretreated $0.1{\mu}g/mL$ of nicotine was first noted at 8hr, and the inhibitory effect was maximal at 12 h. The inhibitory effect at $1{\mu}g/mL$ of nicotine was inhibited maximal at 24 h. Cytotoxic effects of nicotine were noted above $10{\mu}g/mL$ of nicotine. Moreover, Nicotine at 0.1, 1 and $10{\mu}g/mL$concentrations significantly inhibited IL-$1{\beta}$-induced TF-${\kappa}B$ activation. Collectively, these results indicate that in activated HFA, nicotine may inhibit the expression of TNF-${\alpha}$ mRNA through the pathway which suppresses the NF-${\kappa}B$ activation. This study suggests that nicotine might be neuroprotective to dopaminergic neurons in the SN and reduce the incidences of PD.

Er:YAG 레이저와 Er,Cr: YSGG 레이저가 염증유발 마우스조직에 미치는 영향

박태일,이형석,이희종,채창훈,이영주,변광섭,홍순민,최미라,박준우,Park, Tae-Il,Lee, Hyung-Seok,Lee, Hee-Jong,Chae, Chang-Hoon,Lee, Young-Joo,Byeon, Kwang-Seob,Hong, Soon-Min,Choi, Mee-Ra,Park, Jun-Woo 대한악안면성형재건외과학회 2010 Maxillofacial Plastic Reconstructive Surgery Vol.32 No.5

Purpose: This study was performed to find out the effects of the Er:YAG laser (Key Laser) & Er,Cr:YSGG laser (Water Laser) on inflammatory tissues. Materials and Methods: It was performed on about 20 g, 6 weeks male ICR mouses. They were grouped into the control (negative), the inflammation induced 'control'(positive), Er,Cr:YSGG laser exposured group after inducing inflammation, Er:YAG lasere exposured group after inducing inflammation each 15 mouses. The mouses were applicated 0.5% DNFB 1 cc on ear skin twice a day for 4 days until symptom expression. After laser exposure, ear tissues were extracted and defined gene expression by RT-PCR. Then, tissue staining, lymphocytes observation, electromicroscophic laboratory were carried out. Results: Interleukin-$1{\beta}$ was expressed much less in the A-laser exposed group. Interleukin-$1{\beta}$ & Tumor Necrosis Factor-${\alpha}$ were expressed 7 times lesser in the A-laser exposed group. The number of Lymphocytes related to inflammation was decreased rapidly in the A-laser exposed group in vivo. he number of cavity recovered normal was a little bigger in the A-laser exposed group after 5 days Conclusion: The expression of IL-$1{\beta}$ & TNF-${\alpha}$, hitologic change, observation with electron microscope shows that Erbium laser exposure causes lesser inflammation with A-laser rather than B-laser.

연장 가골에 골 이식 대체물 투여가 골 경화에 미치는 영향 : 가토 경골에서의 방사선 및 골 밀도의 변화 Changes of Radiography & Bone Mineral Density in the Tibia of Rabbits

오창욱,김풍택,박병철,송해룡,박일형,백준호,박형진 경북대학교 병원 2003 경북대학교병원의학연구소논문집 Vol.7 No.1

목적 : 골 연장술 후 생기는 연장 가골에 황화 칼슘과 이종 이식골을 투여하여 골 경화 속도에 대한 영향을 알아보기 위한 실험이었다. 연구대상 및 방법 : 성장중인 뉴질랜드 화이트 토끼(2.0-2.5㎏)의 경골 간부에 골막을 보호하고, 절골술을 시행하고, 5일간의 휴지기후 외고정 장치를 이용하여 1주일 동안 7㎜가 연장될 때까지 하루 1㎜씩 2회의 리듬을 가지고 골 연장을 실시하였다. 제1 실험 군 7마리에는 연장이 끝난 직후 황화 칼슘(Osteoset^(ⓡ), Wright medical USA) 1정, 제 2 실험 군 7마리에는 이종 이식골의 일종인 Lubboc 5㎟을 각각 연장된 가골 부에 주입하고, 단순 연장한 대조군 7마리와 함께, 방사선 및 골 밀도비를 측정하고 추시하여, 골 경화의 진행속도를 비교하였다. 방사선 촬영은 전후면 및 측면사진을 1주 간격으로 촬영하였고, 골밀도 측정은 DEXA(dual energy X-ray absorptionmetry, Lunar^(ⓡ)) 장치를 2주일 간격으로 시행하였다. 결과 : 방사선 소견상, 제 1실험군의 연장가골의 완전 경화시간은 평균 14주, 제 2실험군은 154 주로 각각 대조군의 16.9주보다 단축되었으며, 골 밀도 비에서도, 두 실험군에서 최고치가 대조군의 값보다 높고, 최고치까지의 경과기간도 빨랐다. 결론 : 본 연구에서 연장 가골에 황화칼슘 및 이종 이식골의 투여가 골 경화의 기간을 단축시킬 수 있고, 외고정 장치의 빠른 제거에 도움이 될 수 있음을 알았다. Purpose : This study was designed to know the effect of calcium-sulfate and xenograft on the distracted callus after lengthening. Materials & Methods : We had operation of subperiosteal osteotomy and external fixation on the tibial diaphysis of young New Zealand White rabbits(2.0-2.5㎏); after 5 days of latency period, 7㎜(1㎜/day, 2times/day) of tibial lengthening was reached in a week. At 1 week after lengthening, the 1st experimental group of 7 rabbits received a pellet of calcium sulfate(Osteoset, Wright medical, USA) in the distraction gap, and the 2nd experimental group of 7 rabbits received 5㎜ 2 of xenogrfat(Lubboc) in the distraction gap. But, the control group of 7 rabbits did not receive any of above materials. We compared three groups with the changes of radiographic findings at every week and bone mineral ratio(DEXA) at every two weeks. Results : The time to complete consolidation of distraction callus of both experimental group(calcium sulfate;14 weeks, xenograft; 15.4 weeks) was shorter than that of control group(16.9 weeks) in radiographic findings. Maximum value of bone mineral ratio of distraction callus was higher and the time to reach the highest value was also shortened in the both experimental group compared to control group. Conclusion : By use of bone substitutes as like calcium sulfate or xenograft in the distraction callus with external fixator, it may be possible to shorten the consolidation period and the fixator-wearing period.

백혈병 마우스 모델의 동종골수이식에서 활성화된 자연살해세포들의 보충이 이식편대백혈병효과와 이식편대숙주반응에 미치는 영향

엄현석,한치화,박수정,김소연,정낙균,정대철,진종률,최일봉,양형모,서영훈,송현근,최인표,민우성,김춘추 대한조혈모세포이식학회 2001 대한조혈모세포이식학회지 Vol.6 No.1

배경: 백혈병에서 동종골수이식 (allogeneic bone marrow transplantation)의 성공적 치료 효과를 얻기 위해서는 이식편대숙주반응 (graft-versus-host disease, GVHD) 발생의 극복과 재발의 방지가 중요한 과제이다. 골수를 역류원심성 세포분리 (counterflow centrifugal elutriation, CCE) 방법으로 분리하여 얻은 rotor off (R/O) 세포분획은 T 세포의 수는 적지만 조혈모세포들을 다량 포함하고 있어 동종골수이식에서 주조직적합복합체 (major histocompatibility complex, MHC) 차이를 극복할 수 있고, 이식편의 생착 성공과 GVHD 발생 예방에 효과적이다. 그러나 골수로부터 T 세포를 제거하면 백혈병세포를 공격하는 이식편대백혈병 (graft-versus-leukemia, GVL) 효과가 감소되기 때문에 백혈병 재발의 빈도가 높다. 자연살해세포 (natural killer cell, NK cell)의 보충 첨가는 동종골수이식 후 GVHD 발생을 줄이면서 충분한 GVL 효과를 얻을 수가 있다. 따라서 저자는 분리 후 IL-2로 활성화시킨 NK 세포들을 골수 R/O 세포분획과 함께 백혈병 마우스 모델에 동종이식함으로써 GVHD와 GVL에 미치는 효과를 관찰하였다. 방법: Balb/c (H-2^(d)) 마우스에서 유래된 A20 (murine B-lymphoma/leukemia cell line, H-2^(d)) 백혈병 세포를 이식 2 일 전에 Balb/c 마우스에 주입하고, 치사량의 전신 방사선을 조사한 직후에 Balb/c 또는 C57BL/6 (H-2^(b)) 마우스의 골수 R/O 세포분획을 꼬리정맥을 통하여 주입하였다. 이들은 모두 이식 후 6-8 주 이내에 사망하였다. 동종이식의 대조군 (n=9)에는 1 × 10^(7)의 R/O 세포분획만을 주입하였고, 실험군 (n=9)에는 C57BL/6 마우스의 비장세포들로부터 단클론항체들을 이용한 negative selection방법으로 분리한 후 IL-2로 활성화된 5 × 10^(5)의 NK 세포분획을 1 × 10^(7)의 R/O 세포분획과 함께 주입하였다. GVL 효과의 판정은 이식 후 14 일과 28 일 째 되는 날 마우스에서 골수, 비장, 간 등을 얻어 백혈병 세포들의 침윤을 조직학적으로 관찰하였으며, GVHD의 정도는 육안적 관찰법으로 평가하였다. 결과: R/O 세포분획만을 이식한 대조군의 골수, 비장, 그리고 간 조직에서는 A20 백혈병 세포의 침윤이 각각 89% (8/9), 78% (7/9)와 22% (2/9)에서 관찰되었고, R/O 세포분획과 NK 세포분획을 함께 이식한 실험군에서는 비장과 간을 제외한 골수에서만 89% (8/9)에서 A20 백혈병 세포의 침윤이 관찰되어 두 군 사이에 장기별 분포의 차이를 볼 수 있었다 (P= 0.0001). 한편 GVHD는 두 군 모두에서 경하게 나타나서 유의한 차이는 없었다. 또한 생착 부전으로 사망한 마우스는 없었다. 결론: CCE를 이용하여 T 세포를 제거한 동종골수이식에서 NK 세포의 보충은 GVHD의 악화는 일으키지 않으면서, 백혈병의 진행을 억제하는 GVL 효과를 얻을 수 있었다. Background: Allogeneic bone marrow transplantation (BMT) with T cell-depleted marrow accompanies engraftment failure and relapse of leukemia by a loss of the graft-versus-leukemia (GVL) effect frequently, while it can prevent GVHD. Supplement of NK cells could prevent GVHD and enhance GVL effect in several murine allogeneis BMT models Roter off (R/O) cell fraction obtained by counterflow centriation elutriatio (CCO) contains small number of T cells and many hematopoietic stem cells. The aim of this study was to determine the effect of R/O cell fraction supplemented with IL-2 activated NK cells on GVL and GVHD within the leukemic mouse BMT model. Methods: Inoculation of A20 (H-2d, murine B-lymphoma/leukemia, Balb/c origin) cells into Balb/c mice via the tail vein 2 days prior to lethal total body irradiation (TBI) and infusion of the Balb/c BM or C57BL/6 (H-2b) R/O fraction were performed. It resulted in 100% mortality within 6 to 8 weeks. The irradiated mice in the control group were injected with 1 × 107 R/O cell fraction alone (n=9) and in the experimental group mice were injected with 1 × 107 R/O cell fraction plus 5 × 105 negatively selected IL-2 activated NK cell fractions of the spleens via the tail vein (n=9). On day 14 and 28 after BMT, the bone marrows, spleens, and livers of mice were harvested for histopathologic analysis of the infiltrations of leukemic cells. We then evaluated the GVHD within the mice. Results: A histopathologic study of the recipients receiving R/O fraction alone showed infiltration of leukemic cells, 89% (8/9) in bone marrows, 78% (7/8) in spleens, and 22% (2/9) in livers. The experimental group of mice showed only the infiltration of leukemic cells 89% (8/9) in bone marrows, not in spleens and livers. There were the organ differences of the leukemic cells infiltrations between the two groups (P=0.0001). There were no obvious differences in the GVHD scores between these two groups, and severe GVHD was not observed. There was no engraftment failure among groups. Conclusion: Thus, our findings suggest that R/O cell fraction obtained by CCE and supplemented with NK cells can promote GVL effect without mediating clinically overt GVHD in allogeneic BMT of mouse leukemia.

전류제어에 의한 단상유도전동기의 기동특성 개선

박수강,최낙일,백형래,임양수,이기용,신사현 조선대학교 에너지.자원신기술연구소 1998 에너지·자원신기술연구소 논문지 Vol.20 No.1

A single phase induction motor(SPIM) with two windings, main and auxiliary, is probably the most widely used motor in the world due to their ruggedness, low maintenance and simplicity of construction There are several ways of starting single phase motors The most popular arrangements is centrifugal switch An auxiliary winding connected in series with a capacitor, is brought into the circuit during starting The closing and opening of the switch must be speed dependant The switch meets the speed requirements, but it also has many drawback random switching, arcing, many models necessary for different speeds and shaft diameters, space required inside the motors and limited lifetime to name some of them. In this paper, the starting current of single phase induction motor was detected by a small detector and determined TRIAC gate signal. The strategy of current control is based on limited main and auxiliary current angle during starting period in the closed-loop control. The experimental result show the motor's starting characteristics of the proposal starting system and are compared with centrifugal switch starting motor.

前腕部 經穴 取穴에서 骨度分寸法과 一夫法의 比較 硏究

박히준,채윤병,차웅석,박종배,이혜정,이향숙,인창식,고형균,김수영,최일환,김강식,문정배,배기태,유경환,육근영,정병주,손인철,임사비나 WHO COLLABORATING CENTRE FOR TRADITIONAL MEDICINE 2004 東西醫學硏究所 論文集 Vol.2004 No.-

Background : The cun measurement System, an essential and convenient method in locating acupoints, has been widely used in the practice of acupuncture. However, traditional cun measurement has been criticized for its lack of reliability. Objectives : The purposes of this study are to determine if one cun measured by the directional methods have a consistency with that of proportional methods and to investigate which factors are related with these differences, especially in forearm. Methods : The distance between the elbow crease and the wrist crease of forearm was compared to a reference value of one cun obtained by the directional method. In this method, one cun is one third of the distance between index finger and Small finger of a subject, measured at proximal interphalangeal joint. In addition, to investigate the factors influencing the differences between these two methods, we measured the height and body weight and calculated body mass index (BMI). Finally we analyzed the factors correlated with these lengths by linear regression test. Results : The results showed that one cun obtained by the directional methods were significantly different from one cun by the proportional methods in forearm. It was demonstrated that the length acquired with the directional method was more correlated with body weight and body mass index, while the length obtained by the proportional method was more correlated with the height.

Anti-idiotypic 항체가 Hybridoma 세포의 Anti-DNA 항체 합성을 조절하는 기전

박선,박정수,김형일,주민경,장영주,윤정구,김영태 아주대학교 의과학연구소 1996 아주의학 Vol.1 No.1

The regulatory mechanism of anti-idiotypic antibody(anti-id Ab) in the immune response is not fully understood. It has been reported that anti-id Ab suppresses Ab production of lymphocytes or hybridoma cells in vitro, but it does not affect the proliferation of cells or Ab secretion. We investigated whether or not polyclonal anti-id Ab regulates the production of anti-DNA Ab(lgG2a) in hybridoma cells. In addition, the effects of anti-id Ab on the proliferation of cells and on the transcription levels of lg genes were studied to elucidate the cellular and molecular mechanisms for regulation of anti-DNA Ab production in hybridoma cells. The treatment of hybridoma cells with anti-id Ab resulted in an increase in the number of cells producing anti-DNA Ab. However, there was no significant difference in the proliferation rate and mRNA levels of Ig genes between hybridoma cells treated with anti-id Ab, and those treated with normal rabbit serum. These results and our previous data suggest that the number of hybridoma cells producing anti-DNA Ab by anti-id Ab is not directly related with the rate of proliferation of the cells. Furthermore, it appears that the number of hybridoma cells producing IgG class anti-DNA Ab is increased by anti-id Ab, whereas the number of hybridoma cells producing IgM class anti-DNA Ab is down-regulated by anti-id Ab.

치과용 Titanium 합금의 부식거동

박익민,김형일,최석규 大韓齒科器材學會 1991 대한치과재료학회지 Vol.18 No.2

Ti and Ti alloys are used in the dental field because of its high strength-to-density ratio, good fracture properties, corrosion resistance, and excellent biocompatibility. Corrosion characteristics of the cast pure Ti, Ti-6Al-4V, Ti-5Al-2.5Sn, have been investigated in 1% NaCl solution (37℃) and 40% CaCl₂solution (room-temperature) by means of Potentiodynamic polarization method. Corrosion potentials and corrosion current density of Ti alloys were compared to the Co-Cr alloy. The results are as follows: 1. The corrosion resistance of Ti-5Al-2.5Sn alloy was higher than pure Ti, Ti-6Al-4V alloy, Co-Cr alloy in the 37℃, 1% NaCl solution. But in the 40% CaCl₂solution(room-temperature), the corrosion resistance decreases in the order of Ti-6Al-4V, pure Ti, Ti-5Al-2.5Sn alloy. 2. The corrosion product (Ti₂O₂Cl₄) was formed on the corroded surface of Ti alloys in the 1% NaCl and 40% CaCl₂solution.