• Korean Journal of Pharmacognosy
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• v.52 no.1
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• pp.26-33
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• 2021

During blood vessel damage, an essential step in the hemostatic process is platelet activation. However, it is important to properly control platelet activation, as various cardiovascular diseases, such as stroke, atherosclerosis, and myocardial infarction, are also caused by excessive platelet activation. Found primarily in the roots of plants of the genus Artemisia or Scopolia, isoscopoletin has been studied to demonstrate its potential pharmacological effects against Alzheimer's disease and anticancer, but the mechanisms and roles involved in thrombus formation and platelet aggregation are insufficient. This study investigated the effect of isoscopoletin on U46619-induced human platelet activation. As a result, isoscopoletin significantly increased the levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) dose-dependently. In addition, isoscopoletin significantly phosphorylated inositol 1, 4, 5-triphosphate receptor (IP3R) and vasodilator-stimulated phosphprotein (VASP), which are known substrates for cAMP-dependent kinases and cGMP-dependent kinases. Phosphorylated IP3R by isoscopoletin inhibited Ca2+ mobilization from the dense tubular system Ca2+ channels to cytosol, and phosphorylated VASP was involved in the inhibition of fibrinogen binding through αIIb/β3 inactivation in the platelet membrane. Isoscopoletin finally reduced thrombin-induced fibrin clotting production. Therefore, this study suggests that isoscopoletin has a potent antiplatelet effect and may be helpful for platelet-related thrombotic diseases.

• Biomedical Science Letters
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• v.27 no.4
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• pp.270-276
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• 2021

Physiological agents trigger a signaling process called "inside-out signaling" and activated platelets promote adhesion, granule release, and conformational changes of glycoprotein IIb/IIIa (αIIb/β₃). Activated αIIb/β₃ interacts with fibrinogen and initiates a second signaling step called "external signaling". These two signaling pathways can cause hemostasis or thrombosis, and thrombosis is a possible medical problem in arterial and venous vessels, and platelet-mediated thrombosis is a major cause of cardiovascular disease (CVD). Therefore, modulating platelet activity is important for platelet-mediated thrombosis and cardiovascular disease. Esculetin is a coumarin-based physiologically active 6,7-dihydroxy derivative known to have pharmacological activity against obesity, diabetes, renal failure and CVD. Although some studies have confirmed the effects of esculetin in human platelet activation and experimental mouse models, it is not clear how esculetin has antiplatelet and antithrombotic effects. We confirmed the effect and mechanism of action of escultein on human platelets induced by collagen. As a result, esculetin decreased Ca²⁺ recruitment through upregulation of inositol 1, 4, 5-triphosphate receptor. In addition, esculetin upregulates cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP)-dependent pathways and inhibits fibrinogen binding and thrombus contraction. Our results demonstrate the antiplatelet effect and antithrombotic effect of esculetin in human platelets. Therefore, we suggest that esculetin could be a potential phytochemical for the prevention of thrombus-mediated CVD.

• The Korea Journal of Herbology
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• v.24 no.1
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• pp.41-47
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• 2009

Objectives : The objective of this study was to examine the effects of P. oleracea into the HCl-ethanol induced gastritis in rats, and to isolate and determine the chemical compounds from P. oleracea. Methods : The rats were orally administered with crude extract or fractions or isolated compounds of P. oleracea 30 mins before the induction of gastric lesion by oral administration of HCl-ethanol. The gastric lesional area was measured using pixel counting software. Then the chemical compounds from P. oleracea was isolated and determined by LC-MS and NMR. Results : The inhibition effect of oral administration of crude extract of P. oleracea at a dose of 500 mg/kg in HCl-ethanol induced gastritis was similar to cimetidine. Then, aqueous fraction at a dose of 240 mg/kg exhibited the effects similar to cimetidine. Then, the aqueous fraction was further separated by MPLC and yielded four sub fractions. Among those sub fractions, agent II at a dose of 40 mg/kg possessed the strongest effect in the HCl-ethanol induced gastritis. The water fraction yielded-Uridine, Adenosine, Guanosine, which were characterized by Mass, 1H-NMR, 13C-NMR. Conclusions : This study suggest that a P. oleracea and its compounds showed potent efficacy on the development of HCl-ethanol induced gastritis. Thus, P. olaracea can be a potential natural resource for the management of gastritis although the mechanism of action involved in the treatment remains to be explored.

• Korean Circulation Journal
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• v.52 no.3
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• pp.173-197
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• 2022

Treatment options for patients with heart failure (HF) with reduced ejection fraction (HFrEF) have expanded considerably over the past few decades. Whereas neurohormonal modulation remains central to the management of patients with HFrEF, other pathways have been targeted with drugs that have novel mechanisms of action. The angiotensin receptor-neprilysin inhibitors (ARNIs) which enhance levels of compensatory molecules such as the natriuretic peptides while simultaneously providing angiotensin receptor blockade have emerged as the preferred strategy for inhibiting the renin angiotensin system. Sodium glucose cotransporter 2 (SGLT2) inhibitors which were developed as hypoglycemic agents have been shown to improve outcomes in patients with HF regardless of their diabetic status. These agents along with beta blockers and mineralocorticoid receptor antagonists are the core medical therapies for patients with HFrEF. Additional approaches using ivabradine to slow heart rate in patients with sinus rhythm, the hydralazine/isosorbide dinitrate combination to unload the heart, digoxin to provide inotropic support and vericiguat to augment cyclic guanosine monophosphate production have been shown in well-designed trials to have beneficial effects in the HFrEF population and are used as adjuncts to the core therapies in selected patients. This review provides an overview of the medical management of patients with HFrEF with focus on the major developments that have taken place in the field. It offers prospective of how these drugs should be employed in clinical practice and also a glimpse into some strategies that may prove to be useful in the future.

• BMB Reports
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• v.40 no.5
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• pp.678-683
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• 2007

Extracts from the leaves of the Ginkgo biloba are becoming increasingly popular as a treatment that is claimed to reduce atherosclerosis, coronary artery disease, and thrombosis. In this study, the effect of ginkgolide B (GB) from Ginkgo biloba leaves in collagen (10 ${\mu}g/ml$)-stimulated platelet aggregation was investigated. It has been known that human platelets release matrix metallo-proteinase-9 (MMP-9), and that it significantly inhibited platelet aggregation stimulated by collagen. Zymographic analysis confirmed that pro-MMP-9 (92-kDa) was activated by GB to form an MMP-9 (86-kDa) on gelatinolytic activities. And then, activated MMP-9 by GB dose-dependently inhibited platelet aggregation, intracellular $Ca^{2+}$ mobilization, and thromboxane $A_2$ ($TXA_2$) formation in collagen-stimulated platelets. Activated MMP-9 by GB directly affects down-regulations of cyclooxygenase-1 (COX-1) or $TXA_2$ synthase in a cell free system. In addition, activated MMP-9 significantly increased the formation of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), which have the anti-platelet function in resting and collagen-stimulated platelets. Therefore, we suggest that activated MMP-9 by GB may increase the intracellular cAMP and cGMP production, inhibit the intracellular $Ca^{2+}$ mobilization and $TXA_2$ production, thereby leading to inhibition of platelet aggregation. These results strongly indicate that activated MMP-9 is a potent inhibitor of collagen-stimulated platelet aggregation. It may act a crucial role as a negative regulator during platelet activation.

• Food Science of Animal Resources
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• v.36 no.3
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• pp.369-376
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• 2016

This study aimed to investigate the effects of dry aging on the quality of pork loin. Longissimus lumborum muscles were dissected from the right half of five pork carcasses and were used as the control samples. The left halves of the carcasses were aged at 2±1℃ and a relative humidity of 80% for 40 d. The total aerobic bacteria count was similar between the control and dry-aged pork loin (p>0.05). Lactic-acid bacteria was absent in both the control and dry-aged pork loins. Dry-aged pork loin contained low moisture and high protein and ash compared to the controls (p<0.05). The pH was higher and cooking loss was lower in dry-aged pork loin compared to that in the control (p<0.05). Flavor related compounds, such as total free amino acid, hypoxanthine, and inosine of pork loin were higher in dry-aged pork loin; whereas, inosine 5'-monophosphate and guanosine 5'-monophosphate were low in dry-aged pork loin than control (p<0.05). There was no difference in carnosine and anserine content between dry-aged pork loin and the control (p>0.05). Dry-aged pork loin had lower hardness and shear force and received higher core in sensory evaluation than the control (p<0.05). According to the results, dry aging improved textural and sensorial quality of pork loin.

• Journal of Periodontal and Implant Science
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• v.47 no.2
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• pp.66-76
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• 2017

Purpose: Oral wound healing requires gingival fibroblasts to respond to local growth factors. Epigenetic silencing through DNA methylation can potentially decrease the responsiveness of gingival fibroblasts to local growth factors. In this study, our aim was to determine whether the inhibition of DNA methylation sensitized gingival fibroblasts to transforming growth factor-${\beta}1$ (TGF-${\beta}1$). Methods: Gingival fibroblasts were exposed to 5-aza-2'-deoxycytidine (5-aza), a clinically approved demethylating agent, before stimulation with TGF-${\beta}1$. Gene expression changes were evaluated using quantitative polymerase chain reaction (PCR) analysis. DNA methylation was detected by methylation-sensitive restriction enzymes and PCR amplification. Results: We found that 5-aza enhanced TGF-${\beta}1$-induced interleukin-11 (IL11) expression in gingival fibroblasts 2.37-fold (P=0.008). 5-aza had no significant effects on the expression of proteoglycan 4 (PRG4) and NADPH oxidase 4 (NOX4). Consistent with this, 5-aza caused demethylation of the IL11 gene commonly next to a guanosine (CpG) island in gingival fibroblasts. The TGF-${\beta}$ type I receptor kinase inhibitor SB431542 impeded the changes in IL11 expression, indicating that the effects of 5-aza require TGF-${\beta}$ signaling. 5-aza moderately increased the expression of TGF-${\beta}$ type II receptor (1.40-fold; P=0.009), possibly enhancing the responsiveness of fibroblasts to TGF-${\beta}1$. As part of the feedback response, 5-aza increased the expression of the DNA methyltransferases 1 (DNMT1) (P=0.005) and DNMT3B (P=0.002), which are enzymes responsible for gene methylation. Conclusions: These in vitro data suggest that the inhibition of DNA methylation by 5-aza supports TGF-${\beta}$-induced IL11 expression in gingival fibroblasts.

• Korean Journal of Clinical Pharmacy
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• v.21 no.3
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• pp.224-227
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• 2011

Entecavir is a potent and selective guanosine analogue that has demonstrated a significant antiviral efficacy against hepatitis B virus (HBV). The aim of this study was to evaluate the safety and pharmacokinetic profile after a single dose of entecavir 1 mg administration in Korean healthy male subjects. Eight volunteers were enrolled. After a single dose of 1 mg entecavir was orally administered, blood samples were collected at specific time intervals from 0-168 hours. The plasma concentrations of entecavir were determined by LC-MS/MS. The pharmacokinetic parameters were determined from the plasma concentration-time profiles. The mean values for $AUC_{last}$ and $AUC_{inf}$ were $14.84{\pm}7.81ng{\cdot}hr/mL$ and $20.71{\pm}8.80ng{\cdot}hr/mL$, respectively. The mean value for $C_{max}$ was $9.19{\pm}4.91ng/ml$ and median value for $t_{max}$ was 0.58 hr. No adverse events were reported by subjects or found on analysis of vital signs or laboratory tests. The results are suggested to be useful in clinical trials of entecavir in Korean subject including bioequivalence study.

• Korean Journal of Veterinary Research
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• v.22 no.1
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• pp.1-8
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• 1982

The effect of acetylcholine, oxytocin and prostaglandin $F_{2{\alpha}}$ ($PGF_{2{\alpha}}$) on cyclic nucleotide levels in estrogen-primed rabbit whole uterus were studied in the presence and absence of 1-methyl-3-isobutyl xanthine (MIX), a phosphodiestrase inhibitor, and indomethacin, a prostagandin inhibitor. In the absence of MIX, acetylcholine increased guanosine 3', 5'-cyclic monophosphate (cGMP), but had no effect on adenosine 3', 5'-cyclic monophosphate (cAMP) levels. In contrast, oxytocin had no influence on cGMP, but decreased cAMP levels. $PGF_{2{\alpha}}$ increased cGMP and decreased cAMP levels. MIX increased both cAMP and cGMP levels. Oxytocin and $PGF_{2{\alpha}}$ further increased cGMP levels, indicating activation of guanylate cyclase activity. The ratio of cAMP/cGMP was decreased by uterine stinulants both in presence and absence of MIX. Indomethacin elevated cAMP and cGMP revels. The effects of uterine stimulants in the presence of indomethacin on cyclic nucleotide levels were varied from tissue to tisse. In general, oxytocin decreased cGMP and $PGF_{2{\alpha}}$ increased cAMP/cGMP levels, but the effects were statisically nonsignicficant. The cAMP/cGMP ratio was increased by uterine stimulant in the presence of indomethacin. In conclusion, uterine stimulants eased cAMP/cGMP ratio which indicates that the uterine stimulants have opposing effects on adenylate cyclase and guanylate cyclase activities. The endometrium plays a role in the regulation of cyclic nucleotide levels and uterine contraction by means of PG synthesis. Indomethacin has an unknown activities besides both of PG synthetase and phosphodiesterase inhibitions.

• Korean Journal of Microbiology
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• v.43 no.1
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• pp.72-75
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• 2007

Using co-immunoprecipitation, we identified proteins interacting with Streptomyces coelicolor RNase ES, an ortholog of Escherichia coli RNase E that plays a major role in RNA decay and processing. Polyphosphate kinase and a homolog of exoribonuclease polynucleotide phosphorylase, guanosine pentaphosphate synthetase I that use inorganic phophate were co-precipitated with RNase E, indicating a possibility of S. coelicolor RNase ES to form a multiprotein complex called degradosome, which has been shown to be formed by RNase E in E. coli. Polynucleotide phophorylase proteins from these two phylogenetically distantly related bacteria species showed similar RNA cleavage action in vitro. These results imply the ability of RNase ES to form a multiprotein complex that has structurally and functionally similar to that of E. coli degradosome.