• The Korean Journal of Physiology and Pharmacology
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• 제2권2호
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• pp.241-249
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• 1998

Platelet-activating factor(PAF) enhanced interleukin-1(IL-1) activity by the interaction with a specific receptor in rat alveolar macrophages. In this study, we investigated the role of endogenous arachidonate metabolites and intracellular calcium mobilization in the PAF-induced IL-1 activity. Alveolar macrophages were preincubated with 5-lipoxygenase and cyclooxygenase inhibitors 30 min before the addition of PAF and lipopolysaccharide(LPS). After 24h culture, IL-1 activity was measured in the supernate of sample using the thymocyte proliferation assay. Inhibition of 5-lipoxygenase by nordihydroguaiaretic acid and AA-861 completely blocked the PAF-induced enhancement of IL-1 activity with $IC_{50}\;of\;2\;{\mu}M\;and\;5\;{\mu}M$, respectively. In contrast, the inhibition of cyclooxygenase pathway by indomethacin and ibuprofen resulted in the potentiation in PAF-induced IL-1 activity with maximal effect at $1\;{\mu}M\;and\;5\;{\mu}M$, respectively. In addition, leukotriene $B_4$ and prostaglandin $E_2$ production were observed in PAF-stimulated alveolar macrophage culture. As could be expected, 5-lipoxygenase and cyclooxygenase inhibitors abolished PAF- stimulated leukotriene $B_4$ and prostaglandin $E_2$ production, respectively. The effects of PAF on intracellular calcium mobilization in alveolar macrophages were evaluated using the calcium-sensitive dye fura-2 at the single cell level. PAF at any dose between $10^{-16}\;and\;10^{-8}$ M did not increase intracellular calcium. Furthermore, there was no effective change of intracellular calcium level when PAF was added to alveolar macrophages in the presence of LPS or LPS+LTB4, and 4, 24 and 48h after treatment of these stimulants. Together, the results indicate that IL-1 activity induced by PAF is differently regulated through subsequent induction of endogenous 5-lipoxygenase and cyclooxygenase pathways, but not dependent on calcium signalling pathway.

• 대한본초학회지
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• 제27권1호
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• pp.41-49
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• 2012

Objectives : The purpose of this study was to investigate the anti-oxidative and anti-atopic dermatitis effects of persimmon leaf extract obtained from Cheongdo-gun, where more than 60% of Korean persimmon is produced. Methods : Anti-oxidative effects of the crude persimmon leaf extract harvested monthly between May and November were determined by in vitro assay using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide dismutase (SOD)-like reaction. Anti-atopic dermatitis effects of the crude persimmon leaf extract were determined by using collagenase type I inhibition assay and by quantitative assays including serum histamine, prostaglandin E metabolite and leukotriene $B_4$ levels in animal model of atopic dermatitis using Balb/c mice. Results : Persimmon leaf extract harvested in May had higher levels of total phenolic compounds (182.24 mg/g) and flavonoids (23.05 mg/g) than the ones of different month extract. Also, persimmon leaf extract harvested in May showed the most effective extract scavenging activities of DPPH free radical ($13.39{\pm}0.21\;{\mu}g/ml$) and superoxide anion radical ($40.52{\pm}2.32\;{\mu}g/ml$), leading to use the persimmon leaf extract harvested in May for the experiments hereafter. Persimmon leaf extract showed $326.71{\pm}4.6\;{\mu}g/ml$ of 50% inhibitory concentration ($IC_{50}$) for collagenase type I which is responsible for the degradation of extracellular matrix. In addition, persimmon leaf extract application group could decrease serum levels of histamine, prostaglandin E metabolite and leukotriene $B_4$ compared to the negative control in animal model of atopic dermatitis. Especially, persimmon leaf extract showed a significantly decreased serum leukotriene $B_4$ level relative to the levels of histamine and prostaglandin E metabolite. Conclusions : Persimmon leaf extract showed anti-oxidative and anti-atopic dermatitis effects in vitro and in vivo. These results suggest that persimmon leaf extract may have immunoregulatory function for alleviating atopic dermatitis by decreasing collagenase activity and mast cell activation.

• 대한치과교정학회지
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• 제24권4호
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• pp.871-883
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• 1994

This experiment was designed to study possible roles of $interleukin-1\beta$, interleukin-6 and tumor necrosis $factor-\alpha$ in bone remodeling by measuring their effects on $PGE_2,\; LTB_4$ and collagenase production when they were administered to human periodontal ligament fibroblasts. Human periodontal ligament fibroblasts were collected from first premolars extracted for orthodontic treatment. They were incubated in the environment of $37^{\circ}C,\;5\%\;Co^2,\;and\;100\%$ humidity. They were treated with $0.25\%$ trypsin-EDTA solution and centrifuged. PDL cells in the fifth to seventh passage were used for the experiment. Cells were seeded onto the culture dishes and when they were successfully attached, human recombinant $interleukin-1\beta$, interleukin-6, and tumor necrosis $factor-\alpha$ were administered, alone or in combination. They were incubated for 4, 8 and 24 hours and the levels of $PGE_2,\;LTB_4$ and collagenase released into the culture media were assessed by enzymeimmunoassay and collagenase activity assay. The conclusions are as follows: 1. $IL-1\beta\;and\;TNF-\alpha$ were very active in stimulating the production of $PGE_2$ and collagenase by human periodontal ligament fibroblasts, while IL-6 increased $LTB_4$ production. 2. $IL-1\beta$ significantly increased $PGE_2$, but $LTB_4$ Production was not increased. $IL-1\beta$ is thought to act mainly via the cyclooxygenase pathway of arachidonic acid metabolism. 3. IL-6 tended to inhibit $IL-1\beta$ in the production of $PGE_2$ and collagense whereas IL-6 and $TNF-\alpha$ showed auditive effect in the level of $PGE_2$. The above cytokines increased the release of at least one of $PGE_2,\;LTB_4$ and collagenase. It suggests that cytokines are involved in bone remodeling process by stimulating PDL fibroblasts to produce various bone-resorptive agents. The roles of cytokines in bone remodeling as a whole would need further study.

• Journal of Microbiology and Biotechnology
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• 제32권9호
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• pp.1126-1133
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• 2022

This study investigated the contribution of lipoxygenase (LOX) inhibitors, nordihydroguaiaretic acid (NDGA), tetra-O-methyl nordihydroguaiaretic acid (M₄N) and zileuton (ZIL), and thromboxane A2 (TXA₂) inhibitor 4,5-diphenylimidazole (DPI) in the proliferation of Brucella abortus infection. None of the compounds affected the uptake of Brucella into the macrophages. We determined the effect of neutralizing leukotriene B4 (LTB4) receptor and showed that the uptake of the bacteria was inhibited at 30 min post-infection. M₄N treatment attenuated intracellular survival of Brucella at 2 h post-incubation but it was not observed in the succeeding time points. DPI treatment showed reduced survival of Brucella at 24 h post-incubation while blocking LTB4 receptor was observed to have a lower intracellular growth at 48 h post-incubation suggesting different action of the inhibitors in the course of the survival of Brucella within the cells. Reduced proliferation of the bacteria in the spleens of mice was observed in animals treated with ZIL or DPI. Increased serum cytokine level of TNF-α and MCP-1 was observed in mice treated with M₄N or ZIL while a lower IFN-γ level in ZIL-treated mice and a higher IL-12 serum level in DPI-treated mice were observed at 7 d post-infection. At 14 d post-infection, ZIL-treated mice displayed reduced serum level of IL-12 and IL-10. Overall, inhibition of 5-LOX or TXA₂ or a combination therapy promises a potential alternative therapy against B. abortus infection. Furthermore, strong ligands for LTB4 receptor could also be a good candidate for the control of Brucella infection.

• Restorative Dentistry and Endodontics
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• 제21권2호
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• pp.451-469
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• 1996

The purpose of this study was to investigate the effect of calcium hydroxide and glass ionomer cement fillings on the levels of $LTB_4$ and $LTC_4$ in experimentally inflamed rat dental pulp. The dental pulp in the mandibular incisor of wistar rat was irritated by cutting a 5mm deep hole in the dentin with a twist drill bur of 0.5mm diameter, without cooling. The cavities were filled with calcium hydroxide(light-cured) and glass ionomer cement(light cured). The untreated pulp served as control tissue specimen. After cavity preparations, the rat with or without various treatment were sacrificed in various time by decapitation. The dental pulp tissue were carefully removed and the concentrations of $LTB_4$ and $LTC_4$ were determined by radioimmunoassay. And pulps were examined histologically to observe inflammatory feature. The result were obtained as follows : 1. The inflammatory features of pulps were observed microscopically in all experimental groups. And degree of inflammation was decreased with time. 2. The concentrations of $LTB_4$ and $LTC_4$ for all experimental groups were significantly higher than those for control group 6 hours after cavity preparation(p<0.05). 3. The group filled with calcium hydroxide was the lowest, and the group filled with glass ionomer cement, the group of irritation in that order showed increased concentrations of $LTB_4$ and $LTC_4$ 6 hours after cavity preparation. In the concentrations of $LTB_4$, significant differences among 3 groups were noted(p<0.05). 4. The group filled with calcium hydroxide was the lowest, and the group filled with glass ionomer cement, the group of irritation in that order showed increased concentrations of $LTB_4$ and $LTC_4$ 24 hours after cavity preparation. And there were statistically significant difference in concentrations of $LTB_4$ between the group of irritation and the group filled with calcium hydroxide(p<0.05). 5. The group filled with calcium hydroxide was the lowest, and the group filled with glass ionomer cement, the group of irritation in that order showed increased concentrations of $LTB_4$ and $LTC_4$ 48 hours after cavity preparation. But no statistically difference was found (p>0.05). 6. The concentrations of $LTB_4$ and $LTC_4$ in all experimental groups were highest level at 6 hour after experiment and decreased as time progresses(correlation coefficient>0.8).

• Tuberculosis and Respiratory Diseases
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• 제39권4호
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• pp.304-309
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• 1992

연구배경 : 폐포대식세포에서 아라카돈산 대사산물의 생성을 자극하는 일부 인자에 의해서 지속적인 자극시 이와같은 자극으로 인해 생산된 아라키돈산 대사산물이 만성적인 기관지 수축과 섬유화, 계속되는 독성 산소기의 분비를 통하여 잘환의 진행을 항진시키게 된다고 알려져 있고 또한 폐가 외부 물질에 만성적으로 폭로됨으로 인한 질환은 진폐증이 그 대표적인 예라고 할 수 있다. 그러으로 대식세포나 호중구 또는 섬유모세포에서 생산하는 prostaglandin이나 leukotriene등 대사산물의 측정을 통하여 진폐증의 질환의 진행정도를 파악하려는 노력이 계속되고 있으나 아직 명백한 결론을 얻지 못하고 있다. 본 연구는 시험관내에서 폐포대식세포를 유리규산으로 자극시 아라키돈산 대사산물의 측정을 통하여 섬유화 과정에 미치는 prostaglandin $E_2$와 leukotriene $B_4$의 영향을 연구하기 위하여 시행되었다. 방법 : 쥐의 폐포대식세포를 유리규산분진, 자연산 석탄 분진, Lipopolysaccharide, calcium ionophore과 같은 자극제와 같이 배양하고 24, 48시 간후 방사선 동위원소를 이용하여 $PGE_2$와 $LTB_4$를 측정하였다. 결과 : 1) 정상 흰쥐의 폐포대식세포에서 $PGE_2$는 유리규산 자극시 48시간에서 무자극군에 비하여 유의한 감소를 보였다. 2) 실험규폐증군의 폐포대식세포에서 유리된 $PGE_2$는 유리규산 및 자연산 석탄분진으로 자극시 48시간에서 무자극군에 비하여 유의하게 감소하였다. 3) 정상 흰쥐의 폐포대식세포에서 $LTB_4$는 유리규산 자극후 24시간 및 48시간, 그리고 자연산 석탄분진으로 자극시 48시간에서 무자극군에 비하여 유의한 증가를 보였다. 4) 실험 규폐증의 폐포대식세포에서 유리된 $LTB_4$는 유리규산 및 자연산 석탄분진 자극시 장시간 및 48시간에서 무자극군에 비하여 모두 유의하게 증가하였다. 결론 : 본 실험 결과 시험관에서 유리규산과 자연산 석탄분진에 폐포대식세포가 폭로시 폐에 염증반응을 항진시킬 수 있는 방향으로 아라키돈산 대사가 이루어짐을 알았고 이와갈은 아라키돈산 대사의 변화가 진폐증의 병태생리에 중요한 인자로서 작용할 가능성이 있다고 하겠다.

• 대한화장품학회지
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• 제24권3호
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• pp.134-145
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• 1998

Facial hyperpigmentation in women, which is considered to be a serious cosmetic disability and a cause of mental distress, requires proper management. Melanocyte dendricity is a crucial factor affecting epidermal pigmentation. We found that BQ-788, the endothelin-B (ETB) receptor antagonist, blocks the formation of multi-dendricity which is induced by cocultured keratinocytes. Melanocytes in vivo show numerous dendrites which are in close contact with multiple keratinocytes, forming the epidermal-melanin unit. While melanocytes transfer their melanosomes into the neighboring keratinocytes via dendrites, keratinocytes secrete many growth factors and cytokines that influence viability, morphology, and melanin formation of melanocytes. Endothelin-1 (ET-1), prostaglandin E2(PGE2), and leukotriene-C4 (LT-C4) have been suggested as the candidates for increasing dendricity. Other reports suggested that ET-1 has stimulatory effects on proliferation and melanin formation of melanocytes in vitro. In the present study, using type-specific ET receptor antagonists, we observed how the morphology of melanocytes could be modulated in a coculture system. In addition, the roles of ET-1 for morphology and proliferation on melanocytes were evaluated in different culture media. We suggest that ET-1 increases dendricity and proliferation of melanocytes, and that its dendrite-inducing effect and mitogenic effect are regulated independently.

• The Korean Journal of Physiology and Pharmacology
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• 제16권5호
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• pp.313-320
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• 2012

In this study, we focused to identify whether eupatilin (5,7-dihydroxy-3',4',6-trimethoxyflavone), an extract from Artemisia argyi folium, prevents $H_2O_2$-induced injury of cultured feline esophageal epithelial cells. Cell viability was measured by the conventional MTT reduction assay. Western blot analysis was performed to investigate the expression of 5-lipoxygenase by $H_2O_2$ treatment in the absence and presence of inhibitors. When cells were exposed to 600 ${\mu}M$ $H_2O_2$ for 24 hours, cell viability was decreased to 40%. However, when cells were pretreated with 25~150 ${\mu}M$ eupatilin for 12 hours, viability was significantly restored in a concentration-dependent manner. $H_2O_2$-treated cells were shown to express 5-lipoxygenase, whereas the cells pretreated with eupatilin exhibited reduction in the expression of 5-lipoxygenase. The $H_2O_2$-induced increase of 5-lipoxygenase expression was prevented by SB202190, SP600125, or NAC. We further demonstrated that the level of leukotriene $B_4$ ($LTB_4$) was also reduced by eupatilin, SB202190, SP600125, NAC, or nordihydroguaiaretic acid (a lipoxygenase inhibitor) pretreatment. $H_2O_2$ induced the activation of p38MAPK and JNK, this activation was inhibited by eupatilin. These results indicate that eupatilin may reduce $H_2O_2$-induced cytotoxicity, and 5-lipoxygenase expression and $LTB_4$ production by controlling the p38 MAPK and JNK signaling pathways through antioxidative action in feline esophageal epithelial cells.

• Tuberculosis and Respiratory Diseases
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• 제45권2호
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• pp.369-379
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• 1998

연구배경: Platelet-activating factor (PAF)는 염증반응의 중요한 매개체이며, 폐혈관의 투과성을 증가시키고, 급만성 폐동맥 고혈압을 유발하며 leukotriene의 합성을 촉진시킨다. 또한 PAF는 호중구의 화화주성, 응집, 탈과립 및 유착과 leukotriene $C_4$, $D_4$ 및 superoxide anion의 생산에도 영향을 미친다. PAF는 혈소판의 응집과 thromboxane $A_2$의 생산을 초래하여 혈액 응고를 촉진시키며 폐혈관계의 미소색전을 일으켜 폐 손상 발생의 주요원인 중 하나이다. 이와같은 현상은 PAF을 흡입후에도 유사한 반응들이 일어나는 것이 관찰된다. PAF는 급성 호흡곤란 증후군(acute respiratory distress syndrome, ARDS)의 병인에 중요한 매개체 중 하나로 알려져 있다. Surfactant는 폐 방어기전에 영향을 미치는데 첫째, surfactant protein-A(SP-A)와 대식세포간 상호작용이 적절한 대식세포 기능 유지에 중요하다. 둘째, surfactant는 수많은 염증에 관여되는 매개체들을 적절이 조정하며 셋째, surf actant 단백자체가 중요한 산화방지능이었으며 넷째, 호기시 폐포밖으로 외부에서 흡입된 각종 업자(불순물들을 제거한다. 이 중 어느하나에 장애가 오면 ARDS의 병인에 중요한 영향을 미친다. 방 법: PAF를 백서 기도내 투여후 surfactant단백 A, B 및 C의 mRNA 발현 양상을 filter hybridization방법으로 조사하여 surfactant단백 A, B 및 C 유전자 발현에 대한 PAF의 효과를 관찰하여 다음과 같은 결과를 얻었다. 결 과: SP-A mRNA양은 PAF투여군에서 대조군 및 Lyso-PAF투여군에 비하여 각각 37.1% 및 41.6% 유의하게 감소하였다 (p<0.025, p<0.01). SP-B mRNA양은 PAF투여군에서 대조군 및 Lyso-PAF 투여군에 비하여 각각 18.7% 및 32.2% 감소하였으나, 유의한 차는 없었다. SP-C mRNA양은 PAF투여군에서 대조군 및 Lyso-PAF투여군에 비하여 각각 30.7% 및 38.5% 유의하게 감소하였다(p<0.01, p<0.01). 결 론: 이상의 결과로 SP-A, B, C mRNA에 대한 PAF의 억제효과를 확인 하였으며 이와같은 surfactant단백들의 발현에 대한 PAF의 억제효과가 급성 호흡곤란증후군의 병인의 한요인으로 작용할 수 있을것으로 생각된다.