• Journal of Life Science
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• v.22 no.10
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• pp.1352-1358
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• 2012

In acute lung injury (ALI) by lipopolysaccharide (LPS), the underlying cause of infiltration and migration of neutrophils into the alveoli is considered to be from increased production of platelet-activating factor (PAF) in the pulmonary surfactant lining the alveolar lumen. In this study I partially confirmed this concept. LPS increased lung leak and the infiltration of neutrophils in the lung of rats given LPS intratracheally. The migration of neutrophils into the lung, which had caused oxidative stress, was also morphologically identified. I verified that the metabolism of the pulmonary surfactant was affected and that there was increased production of PAF in the pulmonary surfactant, both of which are considered to contribute to ALI by LPS in rats.

• Biomolecules & Therapeutics
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• v.14 no.3
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• pp.160-165
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• 2006

Since platelet-activating factor (PAF) is involved in inflammation, allergic response and anaphylactic shock, PAF receptor antagonists may have potential for controlling these disease conditions. The extract of the leaves of Ginkgo biloba having a higher content of terpenoids (12%) with flavonoids (24%) (YY1224) was prepared in order to obtain the increasing PAF antagonistic activity. As expected, YY1224 showed a higher PAF antagonistic binding affinity ($IC_{50}\;=\;0.09\;{\mu}g/ml$) using $[^3H]PAF$ and rabbit platelets as ligand and receptor source, compared with an $IC_{50}$ of $>\;100\;{\mu}g/ml$ by Egb 761, a standardized extract. YY1224 also showed a higher inhibitory activity against PAF-induced platelet aggregation and NO production from lipopolysaccharide-treated RAW 264.7 cells. In addition, it protected PAF-induced death in mice by oral administration at 15 mg/kg. All these results suggest that YY1224 may show favorable effects on PAF-related disorders.

• Clinical and Experimental Reproductive Medicine
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• v.19 no.1
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• pp.9-14
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• 1992

Platelet activating factor(PAF) has been reported to play a significant role in ovulation, establishment and maintnance of early pregnancy. The object of this study was to investigate the influence of PAF on progesterone secretion in rabbit by measurement of pheripheral blood concentration of progesterone. PAF had no effect on progesterone secretion and did not induce decidual reaction in nonovulatory rabbit. But 8th day of hCG induced pesudopregnant rabbit, PAF significantly increase progesterone secretion. Progesterone level was significantly increased at 0.5 and 4 hours after treatment with $10^{-8}$ M PAF on days 2, 4, 6, 8 of gestation as compared than those treated with normal saline. When PAF was injected 2 days after coitus, progesterone levels on days 4, 6, 10, 14 of gestation was significantly increased than those with saline injected group. These results suggest that PAF increase progesterone secretion from the hCG-primed ovary and during pregnancy in rabbit.

• Biomolecules & Therapeutics
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• v.6 no.3
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• pp.269-275
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• 1998

These studies were conducted to investigate the antiinflammatory effects and the mechanism of action of natural products. We used the methods of "carrageenan induced foot edema" , "PAF (platelet activating factor) induced foot edema" , "inhibition test of vascular permeability" , "inhibition test of white blood cell migration" , "formation of granuloma" and "adjuvant induced arthritis" to examine the antiinflammatory erects of Angelica gigas, Ledebouriella seseloides, Ginkgo biloba and Bamboo salt (Jukyom). The oral administration of the water extract of Angelica gigantis radix, the methanolic extract of Ginkgo folium and the aqueous solution of Bamboo salt showed antiinflammatory effect on carrageenan and PAF induced foot edema in SD rat at a dose of 1 g/kg. The same administration of methanolic extract of Ginkgo folium also inhibited the vascular permeability in mice. The aqueous solution of Bamboo salt inhibited the formation of ganuloma in SD rats at a oral dose of 1 g/kg. Angelica gigantis radix seems to have antiinflammatory effect by inhibition of PAF.

• The Korean Journal of Physiology
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• v.30 no.1
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• pp.77-83
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• 1996

Platelet-activating factor(PAF) is a phospholipid mediator of pulmonary inflammation, and immunologic reaction. In this study, the role of PAF on tumor necrosis factor$(TNF_{-{\alpha}})$ production by rat alveolar macrophages(AM) was examined. When PAF $(10^{-12}{\sim}10{-16}\;M)$ alone was added to AM culture, $(TNF_{-{\alpha}})$ production was not significantly increased above the resting level. In contrast, the combined addition of PAF $(10^{-6}\;M)$ and muramyl dipeptide(MDP) $(1.0\;{\mu}g\ml)$ to AM cultures markedly enhanced $(TNF_{-{\alpha}})$ production with 8.2 fold increase compared with AM culture in resting state. This potentiative effect was 313% above the sum of the separate effects of PAF and MDP. To characterize MDP effects on $(TNF_{-{\alpha}})$ production, the dose-response of AM cultured with various concentrations of MDP was tested. High level of MDP $(10\;{\mu}g\ml)$ could not significantly enhance the potentiation effect on $(TNF_{-{\alpha}})$ production compared with AM cultures with low level of MDP $(0.1\;{\mu}g\ml)$, i.e. 112.5% vs 107.8%, respectively when $10^{-10}$ M of PAF was simultaneously added to the cell culture. These data support that the potentiation of TNF. g production in AM culture is mediated by PAF rather than MDf It was also evaluated whether the similar result was obtained in silica, respirable toxic particle-treated AM culture. $(TNF_{-{\alpha}})$ production was also significantly enhanced in the PAF $(10^{-6}\;M)$ and silica $(50\;{\mu}g\ml)$-added cell cultures with 4.7 fold above the value of silica alone-stimulated cells. These results indicate that PAF can potentiate $(TNF_{-{\alpha}})$ production by MDP-or silica- stimulated AM and suggest that PAF may play a potent role in lung inflammation and disease associated with microbe and occupational dust exposures.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.4
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• pp.479-491
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• 1998

In order to know the pathogenesis of adult respiratory distress syndrome (ARDS) in association with the oxidative stress by neutrophils, the role of platelet activating factor (1-0-alkyl-2-acetyl-snglycero-3-phosphocholine, PAF) was investigated during acute lung injury induced by interleukin- $1{\alpha}$ (IL-1) in rats. An insufflation of IL-1 into the rat's trachea increased the acetyltransferase activity in the lung and the increase of PAF content was followed. As evidences of acute lung injury by neutrophilic respiratory burst, lung leak index, myeloperoxidase activity, numbers of neutrophils in the bronchoalveolar lavage fluid, neutrophilic adhesions to endothelial cells and NBT positive neutrophils were increased after IL-1 treatment. In addition, a direct instillation of PAF into the trachea caused acute lung leak and the experimental results showed a similar pattern in comparison with IL-1 induced acute lung injury. For the confirmation of oxidative stress during acute lung leak by IL-1 and PAF, a histochemical electron microscopy was performed. In IL-1 and PAF treated lungs of rats, the deposits of cerrous perhydroxide were found. To elucidate the role of PAF, an intravenous injection of PAF receptor antagonist, WEB 2086 was given immediately after IL-1 or PAF treatment. WEB 2086 decreased the production of hydrogen peroxide and the acute lung leak. In ultrastructural study, WEB 2086 mitigated the pathological changes induced by IL-1 or PAF. The nuclear factor kappa B (NFkB) was activated by PAF and this activation was inhibited by WEB 2086 almost completely. Based on these experimental results, it is suggested that the PAF produced in response to IL-1 through the remodeling pathway has the major role for acute lung injury by neutrophilic respiratory burst. In an additional experiment, we can also come to conclude that the activation of the NFkB by PAF is thought to be the fundamental mechanism to initiate the oxidative stress by neutrophils causing release of proinflammatory cytokines and activation of phospholipase $A_2$.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.177-177
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• 1998

In the previous report, tetrandrine (TET) and fangchinoline (FAN) showed antithrombotic and antiplatelet aggregation activities. The present study was undertaken to investigate the effects of tetrandrine and fangchinoline on human platelet aggregation, formation of thromboxane B$_2$ and coagulation of platelet poor plasma. TET and FAN inhibited platelet activating factor (PAF) induced human platelet aggregation, but didn't inhibit the specific binding of PAF to its receptor. Meanwhile, TET and FAN also inhibited PAF, thrombin and arachidonic acid induced thromboxane B$_2$ formation in human washed platelets. In addition, neither TET nor FAN showed any anticoagulation activities in the measurement of the activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) using human platelet poor plasma. These results suggest that antithrombotic effects of TET and FAN in mice may be mainly related to the antiplatelet aggregation activities, and the antiplatelet aggregation effects may be related to the intracellular messenger system such as TXA$_2$ formation etc., but not to the binding of PAF to PAF-receptor on the platelet membrane directly.

• IMMUNE NETWORK
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• v.3 no.1
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• pp.38-46
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• 2003

Background: Platelet-activating factor (PAF) induces nuclear factor $(NF)-{\kappa}B$ activation and angiogenesis and increases tumor growth and pulmonary tumor metastasis in vivo. The role of $NF-{\kappa}B$ activation in PAF-induced angiogenesis in a mouse model of Matrigel implantation, and in PAF-mediated pulmonary tumor metastasis were investigated. Methods: Angiogenesis using Matrigel and experimental pulmonary tumor metastasis were tested in a mouse model. Electrophoretic mobility shift assay was done for the assessment of $NF-{\kappa}B$ translocation to the nucleus. Expression of angiogenic factors, such as tumor necrosis factor $(TNF)-{\alpha}$, interleukin $(IL)-1{\alpha}$, basic fibroblast growth factor (bFGF), and vascular endothelial growth factor (VEGF) were tested by RT-PCR and ELISA. Results: PAF induced a dose- and time-dependent angiogenic response. PAF-induced angiogenesis was significantly blocked by PAF antagonist, CV6209, and inhibitors of $NF-{\kappa}B$ expression or action, including antisense oligonucleotides to p65 subunit of $NF-{\kappa}B$ (p65 AS) and antioxidants such as ${\alpha}$-tocopherol and N-acetyl-L-cysteine. In vitro, PAF activated the transcription factor, $NF-{\kappa}B$ and induced mRNA expression of $TNF-{\alpha}$, $IL-1{\alpha}$, bFGF, VEGF, and its receptor, KDR. The PAF-induced expression of the above mentioned factors was inhibited by p65 AS or antioxidants. Also, protein synthesis of VEGF was increased by PAF and inhibited by p65 AS or antioxidants. The angiogenic effect of PAF was blocked when anti-VEGF antibodies was treated or antibodies against $TNF-{\alpha}$, $IL-1{\alpha}$, and bFGF was co-administrated, but not by antibodies against $TNF-{\alpha}$, $IL-1{\alpha}$, and bFGF each alone. PAF-augmented pulmonary tumor metastasis was inhibited by p65 AS or antioxidants. Conclusion: These data indicate that PAF increases angiogenesis and pulmonary tumor metastasis through $NF-{\kappa}B$ activation and expression of $NF-{\kappa}B$-dependent angiogenic factors.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.249-249
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• 1994

PAF (Platelet-activating factor: 혈소판 활성화인자)는 1972년 Benveniste등에 의해 토끼의 호중구 배양 상청액중에서 발견되어 1979년 그 구조가 1-alkyl-2-acethyl-sn glycero-3-phosphocholine의 구조를 갖는 에테르형 인 지질임이 밝혀졌다. 그후 혈소판 이외 과립구, 단구나 macrophage, 혈관내피세포등 조직의 염증담당세포가 다양한 자극에 응하여 PAF를 생성됨이 보고되었다. PAF가 나타내는 대표적 활성으로는 혈소판, 호중구, 단구들의 활성화, 호중구의 유주 활성, 혈관투과성 항진, 혈압강하작용. 기관지 수축 등이 알려졌으며. 또한 염증, 알러지, 천식 endotoxin shock 등 여러질병에 직·간접적으로 관여함이 알려졌다. 이와같은 여러 생리 현상은 PAF의 특이적수용체를 개재하여 일어난다는 것이 밝혀졌다. 따라서 PAF의 다양한 질병의 관여가 밝혀짐으로서, PAF길항제의 개발이 활발히 진행되어왔다. 지금까지 PAF길항제의 개발은 PAF 구조 유사체. benzodiazepam유도체, thiazole유도체 등과 같은 합성품과 ginkolide, kadsurenone과 같은 천연물 유리의 것이 알려져 in vivo model에서도 그 효능이 확인되었다. 본 연구는 이와 같은 배경에서 20여 종의 생약에서 PAF 길항제를 검색하던 중 5종류의 생약에서 PAF 길항작용을 갖는 분획을 찾았기에 이에 보고한다.

• The Korean Journal of Physiology
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• v.29 no.1
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• pp.1-11
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• 1995

Alveolar macrophages play a pivotal role in the pathogenesis of silicosis since the macrophages may release a wide variety of toxic and inflammatory mediators as well as mitogenic growth factors. In the present study, the effects of in vitro exposure to silica on release of various mediator such as reactive oxygen species, platelet activating factor(PAF), and interleukin-1 (IL-1) by alveolar macrophages were examined. First, hydrogen peroxide release from alveolar macrophages was monitored by measuring the change in fluorescence of scopoletin in the absence or presence of graded concentration of silica. Significantly enhanced release of hydrogen peroxide was observed at 0.5 mg/ml and above. A maximal enhancement of 10 fold above control was observed at 5 mg/ml silica. Similarly, in vitro exposure to silica also significantly stimulated the generation of chemiluminescence from alveolar macrophages at 0.5 mg/ml and above with n maximal enhancement of 8 fold at 5 mg/ml silica. Second, PAF release from alveolar macrophages after 30 min incubation at $37^{\circ}C$ in absence or presence of zymosan and silica was determined by measuring $^{3}H-serotonin$ release ability of the conditioned macrophage supernates from platelets. 5 mg/ml zymosan as a positive control fur the PAF assay increased PAF release by 19 % of total serotonin release. Furthermore, silica also resulted in significant enhancement of the PAF release compared with that in unstimulated (control) cells, i.e., $17.7{\pm}5.8%$ and $24.0{\pm}4.9%$ of total serotonin release at 5 mg/ml and 10 mg/ml silica, respectively, which represents the release of nanomole levels of PAF. Lastly, IL-1 production by alveolar macrophages was analysed following their stimulation with lipopolysaccharide (LPS) and silica by their capacity to stimulate thymocyte proliferation. $10\;{\mu}g/ml$ LPS resulted in an 11 fold increase in IL-1 production. In comparison, $50\;{\mu}g/ml$ silica resulted in a 4 fold increase in IL-1 release. These data indicate that in vitro exposure of alveolar macrophages to silica activates the release of various bioactive mediators such as reactive oxygen species, PAF and IL-1 which thus contribute to amplification of inflammatory reactions and regulation of fibrotic responses by the lung after inhalation of silica.