• BMB Reports
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• v.54 no.10
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• pp.516-521
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• 2021

Although arginase primarily participates in the last reaction of the urea cycle, we have previously demonstrated that arginase II is an important cytosolic calcium regulator through spermine production in a p32-dependent manner. Here, we demonstrated that rhaponticin (RPT) is a novel medicinal-plant arginase inhibitor and investigated its mechanism of action on Ca²⁺-dependent endothelial nitric oxide synthase (eNOS) activation. RPT was uncompetitively inhibited for both arginases I and II prepared from mouse liver and kidney. It also inhibited arginase activity in both aorta and human umbilical vein endothelial cells (HUVECs). Using both microscope and FACS analyses, RPT treatments induced increases in cytosolic Ca²⁺ levels using Fluo-4 AM as a calcium indicator. Increased cytosolic Ca²⁺ elicited the phosphorylations of both CaMKII and eNOS Ser1177 in a time-dependent manner. RPT incubations also increased intracellular L-arginine (L-Arg) levels and activated the CaMKII/AMPK/Akt/eNOS signaling cascade in HUVECs. Treatment of L-Arg and ABH, arginase inhibitor, increased intracellular Ca²⁺ concentrations and activated CaMKII-dependent eNOS activation in ECs of WT mice, but, the effects were not observed in ECs of inositol triphosphate receptor type 1 knockout (IP3R1^-/-) mice. In the aortic endothelium of WT mice, RPT also augmented nitric oxide (NO) production and attenuated reactive oxygen species (ROS) generation. In a vascular tension assay using RPT-treated aortic tissue, cumulative vasorelaxant responses to acetylcholine (Ach) were enhanced, and phenylephrine (PE)-dependent vasoconstrictive responses were retarded, although sodium nitroprusside and KCl responses were not different. In this study, we present a novel mechanism for RPT, as an arginase inhibitor, to increase cytosolic Ca²⁺ concentration in a L-Arg-dependent manner and enhance endothelial function through eNOS activation.

• Journal of Pharmacopuncture
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• v.22 no.3
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• pp.160-165
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• 2019

Objectives: The aim of this study was to evaluate the effect of Ribes khorasanicum (R. khorasanicum); a plant growing in north Khorasan of Iran; on cardiovascular and stress oxidative in acute hypertension induced by N-nitro-l-arginine methyl ester (L-NAME), anitric oxide synthase inhibitor. Methods: Rats were divided into Control, L-NAME (10 mg/kg), Sodium Nitroprusside (SNP) (50 mg/kg) + L-NAME and three treated groups with R. khorasanicum (4, 12 and 24 mg/kg) groups + L-NAME. L-NAME and SNP were injected intravenously and extract intraperitoneal. In R. khorasanicum groups, L-NAME was injected 30 min after injection of the extract. Systolic blood pressure (SBP), mean arterial pressure (MAP) and heart rate (HR) were recorded continuously using power lab software. At the end of study oxidative stress parameters including of total thiol content (SH), malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) in heart and aorta of all groups were also measured. Results: In groups 4 and 24 mg/kg extract +L-NAME, there was a non-significant decrease in SBP and MAP compared to L-NAME group but dose 12 mg/kg significantly attenuate the effect of L-NAME(P < 0.05). In L-NAME group the heart and aorta tissues antioxidant enzymes levels decreased, while in treated rats these enzymes significantly increased. Conclusion: The extract of R. khorasanicum in dose 12 mg/kg show anti-hypertensive effect that is mediated by an effect on NO system or antioxidant parameters.

• Research in Vestibular Science
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• v.17 no.4
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• pp.142-151
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• 2018

Objectives: Excitability o medial vestibular nucleus (MVN) in the brainstem can be affected by changes in the arterial blood pressure. Several animal studies have demonstrated that acute hypotension results in the alteration of multiunit activities and expression of cFos protein in the MVN. In the field of extracellular electrophysiological recording, tetrode technology and spike sorting algorithms can easily identify single unit activity from multiunit activities in the brain. However, detailed properties of electrophysiological changes in single unit of the MVN during acute hypotension have been unknown. Methods: Therefore, we applied tetrode techniques and electrophysiological characterization methods to know the effect of acute hypotension on single unit activities of the MVN of rats. Results: Two or 3 types of unit could be classified according to the morphology of spikes and firing properties of neurons. Acute hypotension elicited 4 types of changes in spontaneous firing of single unit in the MVN. Most of these neurons showed excitatory responses for about within 1 minute after the induction of acute hypotension and then returned to the baseline activity 10 minutes after the injection of sodium nitroprusside. There was also gradual increase in spontaneous firing in some units. In contrast small proportion of units showed rapid reduction of firing rate just after acute hypotension. Conclusions: Therefore, application of tetrode technology and spike sorting algorithms is another method for the monitoring of electrical activity of vestibular nuclear during acute hypotension.

• The Korea Journal of Herbology
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• v.32 no.6
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• pp.41-48
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• 2017

Objectives : This study was designed to estimate the antioxidative and neuroprotective effects of Torreyae Semen hot water extracts (TS). Methods : Torreyae Semen was extracted by hot water for 2 hours with a temperature of 105 degrees. Polyphenols and total flavonoid were measured and LC-MS/MS was used to certificate anticipated antioxidative compounds. The antioxidant activities of TS were measured as scavenging effects of 1,1-Diphenyl-2-picrylhydrazyl (DPPH) and Nitrite Oxides (NO). Cell viability and proliferation rate was measured MTT assay. The toxicities to thymocytes and splenocytes were evaluated by the proliferation rate of primary cultured cells of 7 weeks, male Balb/c mice. The antioxidant activities of TS on C6 mouse glioma cells were measured by the analysis of total glutathione contents variation. The neuroprotective effects against oxidative stresses were measured by MTT assay. Results : Polyphenols of TS was $92.00{\pm}1.24{\mu}g/mg$, and total flavonoids was $0.36{\pm}0.14{\mu}g/mg$. TS includes gallocatechin, epigallocatechin, gallocatechin gallate and epigallocatechin gallate. TS included gallocatechin, epigallocatechin, gallocatechin gallate, epigallocatechin gallate. TS showed DPPH and NO scavenging effects as dose-dependent manner at the concentrations of $0-10mg/m{\ell}$. In MTT assay, TS shows no significant toxicity to C6 cells, primary cultured thymocytes and splenocytes of Balb/c mice. TS increased the level of total glutathiones. TS increased cell viabilities of C6 cells against oxidative stresses such as $H_2O_2$, sodium nitroprusside (SNP), Rotenone at the concentrations of $0-0.063mg/m{\ell}$. Conclusions : TS shows the antioxidant and neuroprotecitive effects in these experiments.

• The Korean Journal of Pharmacology
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• v.25 no.1
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• pp.43-51
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• 1989

Responsiveness of muscarinic and alpha adrenoceptor activation on endothelial cells was studied in isolated canine renal artery rings. Ach (10-100 nM), dose dependently, relaxes endothelial intact rings precontracted with phenylephrine ($IC_{50}$ of Ach was 34.5 nM). Selective mechanical destruction of the endothelium transformed the activity of this substance from vasodilatation to vasoconstriction. Acetylcholine induced relaxations could be selectively inhibited competitively by atropine, but could not be inhibited by cyclooxygenase inhibitor. Methylene blue, however, an inhibitor of soluble guanylate cyclase activity, inhibited Ach as well as sodium nitroprusside (SNP) induced relaxation. Relaxation produced by prostacyclin was not modified by methylene blue. On the other hand, alpha adrenoceptor agonist did not relax but contract canine renal artery rings possessing an intact intima precontracted with U-46619. Clonidine, however, selective alpha-2 adrenergic agonist, is more susceptible than phenylepherine, selective alpha-1 adrenergic agonist, to the inhibitory effect of contraction. These results suggest that in canine renal artery rings, 1) muscarinic receptor is responsible for releasing endothelium dependent relaxation factor (EDRF). 2) alpha-1 and alpha-2 adrenergic receptors are present in canine renal artery. 3) relaxation via EDRF is antagonized by methylene blue, providing further evidence that EDRF acts through a cGMP mechanism.

• Journal of Biomedical Engineering Research
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• v.19 no.1
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• pp.59-68
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• 1998

Digital hearing aids offer many advantages over conventional analog hearing aids. With the advent of high speed digital signal processing chips, new digital techniques have been introduced to digital hearing aids. In addition, the evaluation of new ideas in hearing aids is necessarily accompanied by intensive subject-based clinical tests which requires much time and cost. In this paper, we present an objective method to evaluate and predict the performance of hearing aid systems without the help of such subject-based tests. In the hearing impairment simulation(HIS) algorithm, a sensorineural hearing impairment medel is established from auditory test data of the impaired subject being simulated. Also, the nonlinear behavior of the loudness recruitment is defined using hearing loss functions generated from the measurements. To transform the natural input sound into the impaired one, a frequency sampling filter is designed. The filter is continuously refreshed with the level-dependent frequency response function provided by the impairment model. To assess the performance, the HIS algorithm was implemented in real-time using a floating-point DSP. Signals processed with the real-time system were presented to normal subjects and their auditory data modified by the system was measured. The sensorineural hearing impairment was simulated and tested. The threshold of hearing and the speech discrimination tests exhibited the efficiency of the system in its use for the hearing impairment simulation. Using the HIS system we evaluated three typical hearing aid algorithms.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.10
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• pp.1238-1243
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• 2008

The root of Adenophora triphylla is widely used as traditional herbal medicine in Korea. We studied its effects on sodium nitroprusside (SNP) cytotoxicity and antioxidant genes expression in HepG2 cells. To study whether Adenophora triphylla ethylacetate extract (ATea) inhibited NO-induced cell death, HepG2 cells were preincubated for 24 hr with 50 and 100 $\mu$g/mL ATea followed by 24-hr exposure to 0.5 mM SNP (exogenous NO donor). No-induced cytotoxicity was inhibited by pretreatment of ATea, as assessed by mitochondrial dehydrogenase activity (MTT assay). We further investigated the effects of ATea on mRNA levels of various enzymes of the antioxidant system such as Cu, Zn superoxide dismutase (SOD 1), Mn SOD (SOD 2), glutathione peroxidase (GPx), catalase and several enzymes of the glutathione metabolism [glutathione reductase (GR), $\gamma$-glutamyl-cystein synthetase (GCS), glutathione-S-transferase (GST), $\gamma$-glutamyltranspeptidase ($\gamma$-GT), glucose-6-phosphate dehydrogenase (G6PD)] by RT-PCR. CAT, GCS, GR and G6PD mRNA levels were increased after treatment with ATea. The SOD 1, SOD 2, GPx, GST and $\gamma$-GT mRNA levels were not affected in ATea-treated HepG2 cells. We concluded that ATea have an indirect antioxidant effects, perhaps via induction of CAT, GCS, GR and G6PD.

• Journal of Chest Surgery
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• v.42 no.5
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• pp.576-587
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• 2009

Background: The up-regulation of the nitric oxide (NO)-cGMP pathway might be involved in the change of vascular reactivity in rats 3 days after they suffer acute myocardial infarction. However, the underlying mechanism for this has not been clarified. Material and Method: Acute myocardial infarction (AMI) was induced by occluding the left anterior descending coronary artery (LAD) for 30 min (Group AMI), whereas the sham-operated control rats were treated similarly without LAD occlusion (Group SHAM), The concentration-response relationships for phenylephrine (PE), KCl, acetylcholine (Ach) and sodium nitroprusside (SNP) were determined in the endothelium intact E(+) and endothelium denuded E(-) thoracic aortic rings from the rats 3 days after AMI or a SHAM operation. The concentration-response relationships of PE in the E(+) rings from the AMI rats were compared with those relationships in the rings pretreated with nitric oxide synthase (NOS) inhibitor $N{\omega}$-nitro-L-arginine methyl ester (L-NAME) or the cyclooxygenase inhibitor indomethacin. The plasma nitrite/nitrate concentrations were checked via a Griess reaction. The cyclic GMP content in the thoracic aortic rings was measured by radioimmunoassay and the endothelial nitric oxide synthase (eNOS) mRNA expression was assessed by real time PCR. Result: The mean infarct size (%) in the rats with AMI was $21.3{\pm}0.62%$. The heart rate and the systolic and diastolic blood pressure were not significantly changed in the AMI rats. The sensitivity of the contractile response to PE and KCl was significantly decreased in both the E(+) and E(-) aortic rings of the AMI group (p<0.05). L-NAME completely reversed these contractile responses whereas indomethacin did not (p<0.05). Moreover, the sensitivity of the relaxation response to Ach was also significantly decreased in the AMI group (p<0.05). The plasma nitrite and nitrate content (p<0.05), the basal cGMP content (p<0.05) and the eNOS mRNA expression (p=0.056) in the AMI rats were increased as compared with the SHAM group. Conclusion: Our findings indicate that the increased eNOS activity and the up-regulation of the NO-cGMP pathway can be attributed to the decreased contractile or relaxation response in the rat thoracic aorta 3 days after AMI.

• Tuberculosis and Respiratory Diseases
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• v.56 no.2
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• pp.187-197
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• 2004

Background : Nitric Oxide (NO) is a multi-faceted molecule with dichotomous regulatory roles in many areas of biology. NO can promote apoptosis in some cells, whereas it inhibits apoptosis in other cell types. This study was performed to characterize NO-induced cell death in lung epithelial cells and to investigate the roles of cell death regulators including iron, bcl-2 and p53. Methods : A549 cells were used for lung epithelial cells. SNP (sodium nitroprusside) and SNAP (S-nitroso-N-acetyl- penicillamine) were used for NO donor. Cytoxicity assay was done by MTT assay and crystal violet assay. Apoptotic assay was done by fluorescent microscopy after double staining with propidium iodide and hoecst 33342. Iron inhibition study was done with RBCs and FeSO4. For bcl-2 study, bcl-2 overexpressing cells (A549-bcl-2) were used and for p53 study, Western blot analysis and p53 functionally knock-out cells (A549-E6) were used. Results : SNP and SNAP induced dose-dependent cell death in A549 cells and fluorescent microscopy revealed that SNAP induced apoptosis in low doses but necrosis in high doses while SNP induced exclusively necrotic cell death. Iron inhibition study using RBCs and FeSO4 significantly blocked SNAP-induced cell death. And also SNAP-induced cell death was blocked by bcl-2 overexpression. Finally, we found that SNAP activate p53 by Western blot analysis and that SNAP-induced cell death was decreased in the abscence of p53. Conclusion : In lung epithelial cells, NO can induce cell death, more precisely apoptosis in low doses and necrosis in high doses. And iron, bcl-2, and p53 play important roles in NO-induced cell death.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.6
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• pp.809-815
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• 2015

In this study, we confirmed biological compounds from methanol (MeOH) extract of processed Polygoni Multiflori Radix (PPMR), and the radical scavenging effect and oxidative stress protective activity of MeOH extract of PPMR were investigated under in vitro conditions using LLC-$PK_1$ renal epithelial cells. In HPLC analysis, MeOH extract of PPMR contained four species of biological compounds named 2,3,5,4'-tetrahydroxystilbene 2-O-${\beta}$-D-glucoside, emodin, chrysophanol, and rhein. 2,3,5,4'-Tetrahydroxystilbene 2-O-${\beta}$-D-glucoside was detected as the main compound in PPMR as 115.02 mg/kg. MeOH extract of PPMR showed 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) diammonium salt (ABTS), and hydroxyl radical scavenging activities in a concentration- dependent manner. In particular, upon $50{\mu}g/mL$ of PPMR extract treatment, DPPH, ABTS, and hydroxyl radical scavenging activities were approximately 48.4%, 57.9%, and 81.2%, respectively. LLC-$PK_1$ cell viability declined in response to oxidative stress induced by pyrogallol, sodium nitroprusside (SNP), and morpholinosydnonimine (SIN-1) generators of NO, $O_2{^-}$, and $ONOO^-$, respectively. However, MeOH extract of PPMR significantly and dose-dependently inhibited oxidative-stressed LLC-$PK_1$ cell cytotoxicity. In fact, upon $50{\mu}g/mL$ of PPMR extract treatment, LLC-$PK_1$ cell viabilities were approximately 82.1%, 89.1%, and 77.6% compared to stress levels induced by pyrogallol, SNP, and SIN-1, respectively.