• Korean Journal of Bronchoesophagology
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• v.4 no.2
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• pp.182-187
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• 1998

Platelet activating factor (PAP) has been known as implicating as one of potent inflammatory mediators and reported 0 be involved in inflammation and allergy. PAF induces ciliary dysfunction and epithelial damage of human paranasal sinus mucosa in vitro. However, several recent papers have reported that PAF may not readily damage the airway epithelium. The aim of this study was to investigate the ultrastructural evidence to elucidate the pathogenesis of epithelial damage induced by PAF. Sixteen $\mu\textrm{g}$ g of PAF was applied into the maxillary sinuses of 6 rabbits. Rabbits were divided into 2 subgroups along with time interval at 1st and 3rd experimental day, and sinus mucosae were taken for the histopathologic study using electron microscopy. At 1st day, epithelial cells showed no ultrastructural change. Ultrastructures of the cilia were well preserved. Subepithelial space showed no evidence of the infiltration of inflammatory cells. Intravascular platelet aggregation and swelling of endothelial cells were evident. At 3rd day, epithelial cells showed vacuolar degeneration. Fusion of cilia forming giant cilia and focal loss of cilia were evident. Eosinophils were infiltrated in subepithelial and intraepithelial space. Swelling of endothelial cells, and migration of inflammatory cells into the connective tissue were evident. This study implies that epithelial damage induced by PAF may be secondary to the cytotoxicity of mobilized eosinophils rather than direct cytotoxicity of PAF.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.5
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• pp.1494-1504
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• 2004

The present paper reports the effects of Hwaotang an atherosclerosis using a spontaneous experimental model, We have also investigated the pharmacological effect of Hwaotang on collagen- and ADP-induced blood platelet aggregation, thrombin-induced conversion of fibrinogen and fibrinolysis in in vitro experiments, and various effects on stimuli-induced superoxide generation in human neutrophils. Hwao-tang was shown to have inhibitory effect on collagen- and ADP-induced blood platelet aggregation, on thrombin-induced conversion of fibrinogen to fibrin and on the activity of plasminogen or plasmin. Hwao-tang also significantly inhibited fMLP-induced superoxide generation in a concentration-dependent manner, but not that induced by arachidonic acid. Hwao-tang inhibited neutrophil functions, including degranulation, superoxide generation, and leukotriene B4 production, without any effect on 5-lipoxygenase activity. In conclusion, the protection of extracts of Hwao-tang on the ischemic infarction induced artificially might be involved to their inhibition of thrombotic action. The results also indicate that Hwao-tang exerts the effects on superoxide generation related to the inhibition of neutrophil functions.

• Journal of Oriental Neuropsychiatry
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• v.23 no.1
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• pp.115-128
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• 2012

Objectives : To evaluate the in vitro scavenging activity, inhibitory effect of LDL oxidation of pro-oxidant reactive species, anti-platelet aggregative effects and anti-thrombosis effects in response to treatment with SA using various screening methods including biological and non-biological oxidants. Methods : The antioxidant activity concerning extract from SA was studied with in vitro methods by measuring the antioxidant activity by TEAC, measuring the scavenging effects on reactive oxygen species (ROS) [superoxide anion, hydroxyl radical] and on reactive nitrogen species (RNS) [nitric oxide and peroxynitrite] as well as measuring the inhibitory effect on $Cu^{2+}$-induced human LDL oxidation and the inhibitory effect on thrombin-induced platelet aggregation and thrombosis. Results : SA extracts were found to have a potent scavenging activity regarding oxidative stress as well as an inhibitory effect towards LDL oxidation, platelet aggregation, and thrombosis. Conclusions : The SA extracts have anti-oxidative and anti-atherosclerotic effects in vitro system, which can be used for developing pharmaceutical drugs against oxidative stress and atherosclerosis.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.3
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• pp.471-481
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• 2011

Clove has been frequently used as anti-diabetic, anti-microbial, anti-inflammatory, anesthetic drug and remedies for stomachache by coldness. In this study, the antioxidant activity of extract from Clove was studied in vitro methods by measuring the antioxidant activity by TEAC, measuring the scavenging effects on reactive oxygen species (ROS) [superoxide anion, hydroxyl radical] and on reactive nitrogen species (RNS) [nitric oxide and peroxynitrite] as well as measuring the inhibitory effect on $Cu^{2+}$-induced human LDL oxidation. Anti-platelet aggregation and anti-thrombotic effects of Clove extracts were studied ex vivo methods by mesuring the inhibitory effect on thrombin induced platelet aggregation and the fibrinolytic activity. The Clove extracts were found to have a potent scavenging activity, as well as an inhibitory effect on LDL oxidation in vitro. Moreover Clove extracts were exhibited remarkable inhibitory effect on platelet aggregation and fibrinolytic activity. In conclusion, the Clove extracts have anti-oxidative and anti-atherosclerotic effects in vitro and ex vivo system, which can be used for developing pharmaceutical drug against oxidative stress and atherosclerosis.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.221-226
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• 2023

Proper activation and aggregation of platelets are necessary, but excessive or abnormal aggregation can lead to cardiovascular diseases such as stroke, thrombosis, and atherosclerosis. Therefore, identifying a substance that can regulate or inhibit platelet aggregation is important for preventing and treating these diseases. Several studies have shown that certain ginsenoside compounds in Panax ginseng can inhibit platelet aggregation. Among these compounds, Rk3 (G-Rk3) from Panax ginseng needs to be further explored in order to reveal the mechanisms of action during inhibition. G-Rk3 significantly increased amounts of cyclic adenosine monophosphate (cAMP) and led to significant phosphorylation of cAMP-dependent kinase substrates vasodilator-stimulated phosphoprotein and inositol 1,4,5-trisphosphate receptor. Furthermore, the effect of G-Rk3 extended to the inhibition of PI3K/Akt phosphorylation resulting in the reduced secretion of intracellular granules. Ultimately, G-Rk3 effectively inhibited platelet aggregation. Therefore, we suggest G-Rk3's potential as a prophylactic or therapeutic agent for cardiovascular diseases caused by faulty platelet aggregation.

• Translational and Clinical Pharmacology
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• v.26 no.4
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• pp.160-165
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• 2018

Indobufen ($Ibustrin^{(R)}$), a reversible inhibitor of platelet aggregation, exists in two enantiomeric forms in 1:1 ratio. Here, we characterized the anti-platelet effect of S- and R-indobufen using response surface modeling using $NONMEM^{(R)}$ and predicted the therapeutic doses exerting the maximal efficacy of each enantioselective S- and R-indobufen formulation. S- and R-indobufen were added individually or together to 24 plasma samples from drug-naïve healthy subjects, generating 892 samples containing randomly selected concentrations of the drugs of 0-128 mg/L. Collagen-induced platelet aggregation in platelet-rich plasma was determined using a Chrono-log Lumi-Aggregometer. Inhibitory sigmoid $I_{max}$ model adequately described the anti-platelet effect. The S-form was more potent, whereas the R-form showed less inter-individual variation. No significant interaction was observed between the two enantiomers. The anti-platelet effect of multiple treatments with 200 mg indobufen twice daily doses was predicted in the simulation study, and the effect of S- or R-indobufen alone at various doses was predicted to define optimal dosing regimen for each enantiomer. Simulation study predicted that 200 mg twice daily administration of S-indobufen alone will produce more treatment effect than S-and R-mixture formulation. S-indobufen produced treatment effect at lower concentration than R-indobufen. However, inter-individual variation of the pharmacodynamic response was smaller in R-indobufen. The present study suggests the optimal doses of R-and S-enantioselective indobufen formulations in terms of treatment efficacy for patients with thromboembolic problems. The proposed methodology in this study can be applied to the develop novel enantio-selective drugs more efficiently.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.402-407
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• 2023

The regulation of platelet aggregation is crucial for maintaining normal hemostasis, but abnormal or excessive platelet aggregation can contribute to cardiovascular disorders such as stroke, atherosclerosis, and thrombosis. Therefore, identifying substances that can control or suppress platelet aggregation is a promising approach for the prevention and treatment of these conditions. Artemisinin, a compound derived from Artemisia or Scopolia plants, has shown potential in various areas such as anticancer and Alzheimer's disease research. However, the specific role and mechanisms by which artemisinin influences platelet activation and thrombus formation are not yet fully understood. This study investigated the effects of artemisinin on platelet activation and thrombus formation. As a result, cAMP production were increased significantly by artemisinin, as well as phosphorylated VASP and IP₃R which are substrates to cAMP-dependent kinase by artemisinin in a significant manner. The Ca²⁺ normally mobilized from the dense tubular system was inhibited due to IP₃R phosphorylation from artemisinin, and phosphorylated VASP by artemisinin aided in inhibiting platelet activity via αIIb/β3 platelet membrane inactivation and inhibiting fibrinogen binding. Finally, artemisinin inhibited thrombin-induced thrombus formation. Therefore, we suggest that artemisinin has importance with cardiovascular diseases stemming from the abnormal platelets activation and thrombus formation by acting as an effective prophylactic and therapeutic agent.

• Journal of Ginseng Research
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• v.39 no.4
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• pp.354-364
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• 2015

Background: Intracellular $Ca^{2+}$($[Ca^{2+}]_i$) is a platelet aggregation-inducing molecule. Therefore, understanding the inhibitory mechanism of $[Ca^{2+}]_i$mobilization is very important to evaluate the antiplatelet effect of a substance. This study was carried out to understand the $Ca^{2+}$-antagonistic effect of total saponin from Korean Red Ginseng (KRG-TS). Methods: We investigated the $Ca^{2+}$-antagonistic effect of KRG-TS on cyclic nucleotides-associated phosphorylation of inositol 1,4,5-trisphosphate receptor type I ($IP_3RI$) and cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA) in thrombin (0.05 U/mL)-stimulated human platelet aggregation. Results: The inhibition of $[Ca^{2+}]_i$ mobilization by KRG-TS was increased by a PKA inhibitor (Rp-8-BrcAMPS), which was more stronger than the inhibition by a cyclic guanosine monophosphate (cGMP)- dependent protein kinase (PKG) inhibitor (Rp-8-Br-cGMPS). In addition, Rp-8-Br-cAMPS inhibited phosphorylation of PKA catalytic subunit (PKAc) ($Thr^{197}$) by KRG-TS. The phosphorylation of $IP_3RI$ ($Ser^{1756}$) by KRG-TS was very strongly inhibited by Rp-8-Br-cAMPS compared with that by Rp-8-BrcGMPS. These results suggest that the inhibitory effect of $[Ca^{2+}]_i$ mobilization by KRG-TS is more strongly dependent on a cAMP/PKA pathway than a cGMP/PKG pathway. KRG-TS also inhibited the release of adenosine triphosphate and serotonin. In addition, only G-Rg3 of protopanaxadiol in KRG-TS inhibited thrombin-induced platelet aggregation. Conclusion: These results strongly indicate that KRG-TS is a potent beneficial compound that inhibits $[Ca^{2+}]_i$ mobilization in thrombin-platelet interactions, which may result in the prevention of platelet aggregation-mediated thrombotic disease.

• Toxicological Research
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• v.23 no.2
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• pp.159-164
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• 2007

Toxicity screening of a newly developed oral heparin derivative were carried out in 6 male cynomolgus monkeys (Macaca fascicularis), composed of a treatment group and vehicle control group. A newly orally active heparin derivative, developed by Seoul National University, was once given to treatment group at dose of 500 mg/kg. A treatment group did not show any change in body weights, hematological parameters including platelet-related varivables (platelet, PDW, PCT, MPV) and serum biochemical parameters (e.g., AST, ALT, BUN, etc.) for 2 weeks compared with those of vehicle control group. We also confirmed the maximum plasma concentration (Cmax, 1.73 IU/ml) and the time (Tmax, 1 hr) to reach Cmax. The present study will be valuable in the proper interpretation for nonclinical study using cynomolgus monkeys in the development of new drug of heparin derivative.

• Archives of Pharmacal Research
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• v.26 no.7
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• pp.554-558
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• 2003

Platelet activating factor acetylhydrolase (PAF-AH) activity has been identified in cerebrospinal fluid (CSF) samples taken from children with meningitis. We reported that PAF-AH activity is significantly increased, by about 3 fold, in patients with meningitis compared to control subjects. Because of limited knowledge about this enzyme in CSF, we examined the biochemical properties of CSF PAF-AH. PAF-AH of CSF was calcium independent, showed a broad pH spectrum and was relatively heat stable. In addition, this enzyme activity was strongly inhibited by phenylmethanesulfonyl fluoride (PMSF), partially inhibited by p-bromophenacylbromide (p-BPB), uninhibited by iodoacetamide, and moderately stimulated by dithiothreitol (DTT). PAF-AH of CSF did not degrade phospholipid with a long chain fatty acyl group at sn-2 position. This enzyme hydrolyzed PAF and oxidatively modified phosphatidylcholine. Furthermore, we identified a monomeric polypeptide with a molecular weight of approximately 45 kDa by Western blot using human plasma PAF-AH antibody. These results suggested that plasma type PAF-AH activity exist in CSF taken from children with meningitis.