• Molecular Medicine Reports
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• v.19 no.5
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• pp.3767-3774
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• 2019

The contractility of vascular smooth muscle cells (VSMCs) controls the lumen diameter of vessels, thus serving a role in regulating blood pressure and organ blood flow. Although arginases are known to have numerous effects in the biological activities of VSMCs, the effects of arginase II on the constriction of VSMCs has not yet been investigated. When conducting a natural products screen for an inhibitor against arginase, the present study identified that a relatively high concentration of resveratrol (RSV) exhibited arginase inhibitory activity. Therefore, the present study investigated whether RSV could regulate VSMCs contractions and the underlying mechanism. Arginase inhibition by RSV led to an increase in the concentration of the substrate L-Arg and an accompanying increase in the cytosol Ca2+ concentration [(Ca2+)c] in VSMCs. The increased [Ca2+]c induced by RSV and L-Arg treatments resulted in CaMKII-dependent MLC20 phosphorylation. The effects of RSV on VSMCs were maintained even when VSMCs were pre-treated with sirtinol, an inhibitor of Sirt proteins. In a vascular tension assay with de-endothelialized aortic vessels, vasoconstrictor responses, which were measured using phenylephrine (PE), were significantly enhanced in the RSV- and L-Arg-treated vessels. Therefore, although arginase inhibition has exhibited beneficial effects in various diseases, care is required when considering administration of an arginase inhibitor to patients with vessels endothelial dysfunction as RSV can induce vessel contraction.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.3
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• pp.743-748
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• 2005

This study was performed for the investigation of vasodilatory efficacy and its underlying mechanisms of Jagumhuan(JGH), a herbal remedy. JGH produced completely endothelium-dependent relaxation and relaxed phenylephrine(PE)-precontracted aorta in a concentration dependent manner. The magnitude of relaxation was greater in PE induced contraction than that of KCl, suggesting involvement of $K^+$ channel in the relaxant effect. Both glibenclamide$(10^{-5}M)$, a $K_{ATP}$ channel inhibitor and indometacin, a cyclooxygenase inhibitor, completely prevented this relaxation. The relaxation effects of JGH, involve in part the release of nitric oxide from the endothelium as pretreatment with L-NAME, an NOS inhibitor, and methylene blue, a cGMP inhibitor, attenuated the responses by 62% and 58%, respectively. In addition, nitrite was produced by JGH in human aortic smooth muscle cells and human umbilical vein endothelial cells. The relaxant effect of JGH was also inhibited by 55.41% by tetraethylammonium(TEA; 5mM), a $K_{Ca}$ channel inhibitor. In the absence of extracellular $Ca^{2+}$, pre-incubation of the aortic rings with JGH significantly reduced the contraction by PE, suggesting that the relaxant action of the JGH includes inhibition of $Ca^{2+}$ release from intracellular stores. These results indicate that in rat thoracic aorta, JGH may induce vasodilation through ATP sensitive $K^+$ channel activation by prostacyclin production. However, the relaxant effect of JGH may also mediated in part by NO pathways and $Ca^{2+}$ activated $K^+$ channel.

• Journal of the Korean Chemical Society
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• v.57 no.6
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• pp.672-676
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• 2013

The corrosion inhibition nature of Ginger affinale extract for the corrosion of mild steel in 0.5N $H_2SO_4$ was investigated using weight loss, electrochemical impedance and potentiodynamic polarization methods. The results revealed that Ginger affinale extract acts as a good corrosion inhibitor in 0.5N $H_2SO_4$ medium. The inhibition efficiency increased with an increase in inhibitor concentration. The inhibition could be attributed to the adsorption of the inhibitor on the steel surface.

• Korean Journal of Clinical Pharmacy
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• v.9 no.1
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• pp.62-65
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• 1999

Inorganic phosphate (Pi) in rabbit plasma was found to block completely phosphotyrosine phosphatase (PTPase) activity without affecting the alkaline phosphatase (ALPase) activity. Our results provided that (1) PTPase activity and inhibitor are separated after G-25 gel-filtration. (2) This inhibitor is heat stable and trypsin-resistant and it can be removed by dialysis using 3 Kd cut-off tubing. (3) The elution pattern of the inhibitor is identical to that of Pi, and by performing a seperate run with inorganic phosphate. (4) The PTPase activity was recovered following an incubation with $CaCl_2$ (10 mM).

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.1
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• pp.96-103
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• 1998

Lead-acid battery is being most widely used with secondary battery because of its low price, and long life cycles. But According to using for a long time, its voltage, capacity, and recovery ability is decreased gradually. Therefore there are many papers about improving the property of a lead-acid battery. One of them is to slow down sulfation due to formation of inner PbSO sub(4) by adding inhibitor to electrolyte, however it was not well known what is inhibitor's composition and its role acting on both cathodic and anodic electrode because of its know-how of every country and companies. The purpose of this paper is to study about improvement of property of lead-acid battery by adding one of the inhibitor to H sub(2) SO sub(4) electrolyte.

• Corrosion Science and Technology
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• v.21 no.1
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• pp.9-20
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• 2022

The aim of this paper is to study corrosion inhibition of Aluminum with Capparis decidua extract. The study was performed in a 1.0 M solution of hydrochloric acid (HCl) and was monitored both by measuring mass loss and by using electrochemical and polarization methods. A scanning electron microscopy (SEM) technique was also applied for surface morphology analysis. The results revealed high inhibition efficiency of Capparis decidua extract. Our data also determined that efficiency is governed by temperature and concentration of extract. Optimum (88.2%) inhibitor efficiency was found with maximum extract concentration at 45 o C. The results also showed a slight diminution of aluminum dissolution when the temperature is low. Based on the Langmuir adsorption model, Capparis decidua adsorption on the aluminum surface shows a high regression coefficient value. From the results, the activation enthalpy (∆H#) and activation entropy (∆S#) were estimated and discussed. In conclusion, the study clearly shows that Capparis decidua extract acted against aluminum corrosion in acidic media by forming a protective film on top of the aluminum surface.

• Biomolecules & Therapeutics
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• v.22 no.2
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• pp.155-160
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• 2014

Thelephoric acid is an antioxidant produced by the hydrolysis of polyozellin, which is isolated from Polyozellus multiplex. In the present study, the inhibitory effects of polyozellin and thelephoric acid on 9 cytochrome P450 (CYP) family members (CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A4) were examined in pooled human liver microsomes (HLMs) using a cocktail probe assay. Polyozellin exhibited weak inhibitory effects on the activities of all 9 CYPs examined, whereas thelephoric acid exhibited dose- and time-dependent inhibition of all 9 CYP isoforms ($IC_{50}$ values, $3.2-33.7{\mu}M$). Dixon plots of CYP inhibition indicated that thelephoric acid was a competitive inhibitor of CYP1A2 and CYP3A4. In contrast, thelephoric acid was a noncompetitive inhibitor of CYP2D6. Our findings indicate that thelephoric acid may be a novel, non-specific CYP inhibitor, suggesting that it could replace SKF-525A in inhibitory studies designed to investigate the effects of CYP enzymes on the metabolism of given compounds.

• Exercise Science
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• v.26 no.3
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• pp.229-237
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• 2017

PURPOSE: This study was to investigate the Glycolysis mediated sarcoplasmic reticulum (SR) $Ca^{2+}$ signal regulates mitochondria $Ca^{2+}$ during skeletal muscle contraction by using glycolysis inhibitor. METHODS: To examine the effect of Glycolysis inhibitor on SR and mitochondria $Ca^{2+}$ content, we used skeletal muscle fiber from gastrocnemius muscle. 2-deoxy glucose and 3-bromo pyruvate used as glycolysis inhibitor, it applied to electrically stimulated muscle contraction experiment. Intracellular $Ca^{2+}$ content, SR, mitochondria $Ca^{2+}$ level and mitochondria membrane potential (MMP) was detected by confocal microscope. Mitochondrial energy metabolism related enzyme, citric acid synthase activity also examined for mitochondrial function during the muscle contraction. RESULTS: Treatment of 2-DG and 3BP decreased the muscle contraction induced SR $Ca^{2+}$ increase however the mitochondria $Ca^{2+}$ level was increased by treatment of inhibitors and showed and overloading as compared with the control group. Glycolysis inhibitor and thapsigargin treatment showed a significant decrease in MPP of skeletal muscle cells compared to the control group. CS activity significantly decreased after pretreatment of glycolysis inhibitor during skeletal muscle contraction. These results suggest that regulation of mitochondrial $Ca^{2+}$ levels by glycolysis is an important factor in mitochondrial energy production during skeletal muscle contraction CONCLUSIONS: These results suggest that mitochondria $Ca^{2+}$ level can be regulated by SR $Ca^{2+}$ level and glycolytic regulation of intraocular $Ca^{2+}$ signal play pivotal role in regulation of mitochondria energy metabolism during the muscle contraction.

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.3
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• pp.161-165
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• 2004

Exogenous carbon monoxide (0.2%) increases L-type calcium $(Ca^{2+})$ current in human jejunal circular smooth muscle cells. The stimulatory effect of carbon monoxide (CO) on L-type $Ca^{2+}$ current is inhibited by pre-application of L-NNA, a classical competitive inhibitor of nitric oxide synthase (NOS) with no significant isoform selectivity (Lim, 2003). In the present study, we investigated which isoform of NOS affected CO induced stimulation of L-type $Ca^{2+}$ current in human jejunal circular smooth muscle cells. Cells were voltage clamped by whole-cell mode patch clamp technique, and membrane currents were recorded with 10 mM barium as the charge carrier. Before the addition of CO, cells were pretreated with each inhibitor of three NOS isoforms for 15 minutes. CO-stimulating effect on L-type $Ca^{2+}$ current was partially blocked by N-(3-(Amino-methyl) benzyl) acetamidine 2HCl (1400W, an iNOS inhibitor). On the other hand, 3-bromo-7-nitroindazole (BNI, a nNOS inhibitor) or $N^5-(1-Iminoethyl)-L-ornithine$ dihydrochloride (L-NIO, an eNOS inhibitor) completely blocked the CO effect. These data suggest that low dose of exogenous CO may stimulate all NOS isoforms to increase L-type $Ca^{2+}$ channel through nitric oxide (NO) pathway in human jejunal circular smooth muscle cells.

• YAKHAK HOEJI
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• v.56 no.2
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• pp.136-143
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• 2012

Type 2 Diabetes Mellitus (T2DM) is characterized by high blood glucose in the context of insulin resistance and relative insulin deficiency. Diabetes is often initially managed by increasing exercise and dietary modification. As the condition progresses, medications may be needed such as oral sulfonylurea or others. Recently, dipeptidyl peptidase 4 (DPP- 4) Inhibitor is new drug which can control blood glucose by increasing the active levels of incretin hormone in the body. However, researches have been carried out for mostly Caucasian and Japanese, not for Koreans at all. Therefore, this study was to evaluate the efficacy and safety of DPP-4 inhibitor (Sitagliptin, Vildagliptin) in patients with T2DM in Koreans. This study was carried out retrospectively with reviewing of medical records from the 141 patients who received sitagliptin or vildagliptin over 24 week periods from January 2009, to December 2009. Information including demographics, concomitant medication, disease duration, and exercise was evaluated. $HbA_{1c}$, random blood glucose, post prandial 2 hour glucose, blood pressure, AST, ALT, serum creatinine, total cholesterol, triglyceride levels were also collected at baseline and endpoint (at 24 weeks). In each post-treatment group, $HbA_{1c}$, random blood glucose and post prandial 2 hour glucose levels were decreased significantly from baseline in the sitagliptin group (-0.82%, -28.76 mg/dl, -46.65 mg/dl) and vildagliptin group(-1.22%, -27.96 mg/dl, -67.2 mg/dl). Greater $HbA_{1c}$ mean reductions from baseline to 24 weeks were seen in patients with higher baseline values (>7.0%), with shorter disease durations (${\leq}1$ year) compared with those with lower baseline values (<7.0%), with longer disease durations (>1 year) in both sitagliptin and vildagliptin groups. The incidences of hypoglycemia, headache and upper respiratory infection were 0%, 8.7%, 5.8% in sitagliptin group and 2.8%, 8.3%, 6.9% in vildagliptin group. In conclusion, our results showed DPP-4 inhibitor provided similar efficacy compared with sulfonylurea after 24 weeks of treatment and were safer than sulfonylurea in hypoglycemia for Korean T2DM. Also vildagliptin was associated with significant improvement in $HbA_{1c}$ reduction in Korean patient with subgroup (body mass index<25 $kg/m^2$, metformin dose${\geq}$1000 mg, p<0.05) compared to sitagliptin. Therefore, even though DPP-4 inhibitor use for Korean needs to be studied more consistently in the future, DPP-4 inhibitor is a safe and effective drug for Korean T2DM based on our result.