Publications by authors named "Yun-Choi Hye Sook"

Tetrahydroisoquinoline alkaloids (THIs) have shown to increase survival and beneficial effect on animal model of sepsis, partly due to heme oxygenase-1 (HO-1) induction. Here, we aimed to compare a limited series of synthesized THIs on HO-1 induction and inhibitory effect of iNOS and COX-2 expression in lipopolysaccharide (LPS)-activated RAW264.7 cells.

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Although it was thought that platelets did not play a significant role in the pathogenesis of venous thromboembolism (VTE), several studies demonstrated that a marked activation of platelets occurs in patients with VTE. We carried out a case-control study to investigate the effect of the T744C P2RY12 polymorphism on the risk of VTE in the Korean population. We enrolled 154 consecutive patients with VTE and 415 healthy controls.

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Platelet aggregation plays crucial roles in the formation of hemostatic plugs and thrombosis. Although it was recently shown that canonical Wnt signaling negatively regulates platelet aggregation, the role of non-canonical Wnt signaling remains unknown. Here, we observed that Wnt5a, one of the non-canonical Wnts, positively regulated platelet aggregation.

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Impaired responsiveness of platelets to epinephrine (epi) and other catecholamines (CA) has been reported in approximately 20% of the healthy Korean and Japanese populations. In the present study, platelet aggregation induced by epi was potentiated by RO 31-8220 (RO) or Gö 6983 (Gö). Phosphorylated Akt (p-Akt) was very low in epi-stimulated PRP from CA-hypo-responders (CA-HY), whereas it was detected in those from CA-good responders (CA-GR).

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Cinnamomum cassia is a well-known traditional medicine for improvement of blood circulation. An extract of this plant showed both platelet anti-aggregation and blood anti-coagulation effects in preliminary testing. Among the 13 compounds obtained from this plant, eugenol (2), amygdalactone (4), cinnamic alcohol (5), 2-hydroxycinnamaldehyde (7), 2-methoxycinnamaldehyde (8), and coniferaldehyde (9) showed 1.

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The roots of two Paeoniaceae family members have long been used as traditional medicines in Korea, China, and Japan. Dry roots of Paeonia lactiflora and dry root bark of P. suffruticosa are used under the traditional names of Paeoniae Radix and Moutan Cortex, respectively.

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Seven ginsenosides, namely Rg6 (1), F4 (2), Rk3 (3), Rh4 (4), Rs3 (5), Rs4 (6) and Rs5 (7) isolated from processed ginseng were evaluated for their effects on platelet aggregation induced by adenosine diphosphate (ADP), collagen, arachidonic acid (AA) and U46619 (thromboxane A2 mimetic drug). Ginsenosides Rg6, F4 and Rk3 showed inhibitory activity (IC50 = 76 microM, 114 microM and 128 microM, respectively) on AA-induced platelet aggregation. The corresponding IC50 values were comparable to that of acetylsalicylic acid (ASA) (63 microM).

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In spite of their potential as biologically active compounds, the high molecular mass and viscous natures of fucoidans have hampered their applications especially as a therapeutic agent. Herein the fucoidan-degrading enzyme activities were partially purified from the cultured cells of Sphingomonas paucimobilis PF-1 mainly by ammonium sulfate precipitation. This enzyme preparation degraded fucoidans from the Korean Undaria pinnatifida sporophyll into several low-molecular weight fuco-oligosaccharides (LMFOs) with less than 3,749 Da.

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Platelets are highly reactive components of the circulatory system. The cytoskeleton of a platelet is an important structure for platelet aggregation as stimulated by several agonists. An anticancer agent, taxol, has been suggested to exert platelet anti-aggregating activity by stabilizing microtubules during the aggregation process.

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Impaired responsiveness to epinephrine and other catecholamines (CA) were previously reported in platelets of 20 approximately 30% healthy Japanese and Koreans. In the present study, the possible mechanisms of different responsiveness to CA in platelets of CA hypo-responders (CA-HY) and CA good-responders (CA-GR) were investigated. Increased platelet-leukocyte conjugate (PLC) formations were observed with whole blood of CA-GR than with that of CA-HY in both non-stimulated [mean fluorescence intensity (MFI) values: 1.

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Four dammarane glycosides, namely ginsenosides Rk1 (1), Rg5 (2), 20(S)-Rg3 (3), and 20(R)-Rg3 (4), isolated from a new processed ginseng, were evaluated for their inhibitory activity against platelet aggregation induced by adenosine diphosphate (ADP), collagen, arachidonic acid (AA) and U46619 (thromboxane A2 mimetic agent). Ginsenoside Rk1 and Rg5 inhibited AA-induced platelet aggregation in a dose dependent manner. Their activity against AA-induced platelet aggregation were found to be 8-22 fold higher than that of a known antiplatelet drug acetylsalicylic acid (ASA).

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Aims: We examined our hypothesis that CKD712, (S)-1-(alpha-naphthylmethyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, selectively inhibits vascular adhesion molecule-1 (VCAM-1) but not intracellular adhesion molecule-1 (ICAM-1) expression via activation of PTEN in human umbilical vein endothelial cells (HUVECs) activated with lipopolysaccharide (LPS).

Methods And Results: In order to do this, cells were pretreated with CKD712 1h prior to stimulate with LPS (1microg/ml) for 16h, and VCAM-1 and ICAM-1 levels were measured by Western blot. We found that CKD712 dose-dependently inhibited VCAM-1 but not ICAM-1 expression after LPS stimulation in HUVECs.

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We examined our hypothesis that (S)-1-(alpha-naphthylmethyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (CKD712) inhibits apoptosis in myocardial ischemia and reperfusion (I/R) injury in vivo via activation of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway and by reducing inflammation during I/R. To do this, we induced a 30-min period of ischemia by occlusion of the left anterior descending coronary artery of the rat followed by a 2-h (for phosphorylation of Akt), 6-h (for biochemical analysis), or 24-h (for functional analysis) period of reperfusion to determine the effect of CKD712 treatment. Pretreatment with CKD712 significantly improved myocardial function as evidenced by an increase in the +/-dP/dt and a decrease in the infarct size, which were antagonized by a PI3K inhibitor, wortmannin (WT).

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Aspirin is known to suppress platelet function markedly. However, aspirin at concentrations higher than 1 mM was observed to augment 1.3 microM U46619 (a stable thromboxane receptor (TP receptor) agonist) induced human platelet aggregation in this study.

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Introduction: A previous report assigned 35 healthy Koreans into five groups (groups A to E) based on their platelet responsiveness to catecholamines (CA). The present work aimed to elucidate the possible mechanism of heterogeneous responsiveness to CA in normal subjects.

Materials And Methods: The degrees of aggregation in platelet rich plasma (PRP) were measured with a turbidimetric method.

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A methanol extract of Sophora japonica was subjected to anti-platelet activity guided fractionation affording the isolation of four flavonoids and six flavonoid-glycosides: biochanin A (1), irisolidone (2), genistein (3), sissotrin (4), sophorabioside (5), genistin (6), tectoridin (7), apigenin (8), quercitrin (9), and rutin (10). The structure of each compound was determined by a variety of spectroscopic methods. Among the compounds, 1, 3, and 7 showed approximately 2.

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We found that CKD712, an S enantiomer of YS49, strongly inhibited inducible nitric oxide synthase (iNOS) and NO induction but showed a weak inhibitory effect on cyclooxygenase-2 (COX-2) and PGE(2) induction in LPS-stimulated RAW 264.7 cells. We, therefore, investigated the molecular mechanism(s) responsible for this by using CKD712 in LPS-activated RAW264.

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Optically active tetrahydroisoquinoline alkaloids, (R)-(+)-higenamine (1R) and (S)-(-)-higenamine (1 S), and their optically active 1-naphthylmethyl analogues (2 and 3), were synthesized by enantioselective hydrogenation of the corresponding dihydroisoquinoline intermediates 7 as a key step. The evaluation of the platelet anti-aggregation effect demonstrated clearly that the (S)-(-)-enantiomers, 1S, 2S, and 3S, had higher inhibitory potency than the corresponding (R)-(+)-antipodes, 1R, 2R, and 3R, respectively, to platelet aggregation induced by epinephrine. 1S enantiomer was superior to the corresponding 1R enantiomer in attenuating all of the disseminated intravascular coagulation (DIC) and multiple organ failure (MOF) parameters tested, while the S enantiomers 2S and 3S ameliorated some of the DIC and MOF parameters more effectively than the corresponding antipodes 2R and 3R.

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Quercetin, one of the flavonoids, is a compound of low molecular weight found in various plants and shows a wide range of diverse neuropharmacological actions. In fruits and vegetables, quercetin exists as monomer- (quercetin-3-O-rhamnoside) (Rham1), dimer- (Rutin), or trimer-glycosides [quercetin-3-(2G-rhamnosylrutinoside)] (Rham2) at carbon-3. In the previous studies, we demonstrated that quercetin inhibits both glycine and 5-hydroxytryptamine type 3, (5-HT3A) receptor channel activities expressed in Xenopus oocytes.

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Overexpression of the gene for heme oxygenase (HO)-1 leads to a reduction in pressor responsiveness to angiotensin II (Ang II) in experimental animals. Using rat vascular smooth muscle cells (VSMCs), we tested whether YS 49 [1-(alpha-naphtylmethyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline] inhibits Ang II-stimulated proliferation of VSMCs via induction of HO-1. YS 49 induced HO-1 protein production in a dose-and time-dependent manner in VSMCs.

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Activation of the inducible nitric oxide synthase (iNOS) pathway contributes to inflammation-induced osteoporosis by suppressing bone formation and causing osteoblast apoptosis. We investigated the mechanism of action by which YS-51S, a synthetic isoquinoline alkaloid, inhibits iNOS expression and nitric oxide (NO) production in ROS 17/28 osteoblast cells activated with the mixture of TNF-alpha, IFN-gamma and LPS (MIX). YS-51S, concentration- and time-dependently, increased heme oxygenase (HO-1) expression.

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Oxidative stress plays an important role in the pathophysiology of several vascular diseases such as atherosclerosis, and great attention has been placed on the protective role of heme oxygenase-1 (HO-1) for vasculature against oxidant-induced injury. We tested whether the protective effects of YS 51, 1-(beta-naphtyl-methyl)-6,7-dihydroxy-1,2,3,4,-tetrahydroisoquinoline, against hydrogen peroxide (H2O2)-induced cell injury is associated with HO-1 activity in bovine aortic endothelial cells (BAEC). YS 51 increased HO-1 expression and activity in concentration-dependent manners (10-100 microM) and time-dependent manners (1, 3, 6, 18 h), which were correlated well with its protective effect against H2O2-induced injury.

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An aryltetralin lactone, (-)-(1S,2R,3R)-1-(3',4'-methylenedioxyphenyl)-3-(hydroxymethyl)-6,7-dimethoxy-1,2,3,4-tetrahydronaphthalene-2-carboxylic acid lactone, was isolated from the methanol extract of the aerial parts of Bupleurum falcatum and named bupleurumin. The structure of the compound was determined on the basis of chemical and spectroscopic methods, including two-dimensional NMR spectrometry (e.g.

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The effects of 2-naphthylethyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (THI 53), on nitric oxide (NO) production and inducible nitric-oxide synthase (iNOS) protein induction by lipopolysaccharide (LPS) were investigated in RAW 264.7 cells and mice. In cells, THI 53 concentration dependently reduced NO production and iNOS protein induction by LPS.

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