• The Korean Journal of Physiology and Pharmacology
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• v.11 no.5
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• pp.175-182
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• 2007

Members of prostaglandin(PG) E-series elicit cellular effects mainly through adenylyl cyclase-cAMP signaling. The role of $PGE_2$-induced increase in cAMP has been shown to be compartmentalized in the cardiac myocytes: $PGE_2$-induced increase of cAMP is not involved in the control of cardiomyocytic contraction. The purpose of the present study was to define the effect of $PGE_1$ on the cGMP levels and the role of $PGE_1$ in the atrial secretory function. Experiments were performed in perfused beating rabbit atria and atrial contractile responses, cGMP and cAMP efflux, and atrial natriuretic peptide(ANP) secretion were measured. $PGE_1$ increased cGMP as well as cAMP efflux concentration in a concentration-dependent manner, however, no significant changes in atrial secretory responses were observed(with $1.0{\mu}M\;PGE_1$; for cGMP, $144.76{\pm}37.5%$, n=11 versus $-16.81{\pm}4.76%$, n=6, control, p<0.01; for cAMP, $187.60{\pm}41.52%$, n=11 versus $7.38{\pm}19.44%$, n=6, control, p<0.01). $PGE_1$ decreased atrial dynamics slightly but transiently, whereas $PGE_2$ showed similar effects but with lower potency. Isoproterenol increased atrial cAMP efflux(with 2.0 nM; $145.71{\pm}41.89$, n=5 versus $7.38{\pm}19.44%$, n=6, control, p<0.05) and mechanical dynamics and decreased ANP secretion. The $PGE_1$-induced increase in cGMP efflux showed a bell-shaped concentration-response curve. $PGE_1$-induced increase of cGMP efflux was not observed in the presence of L-NAME, an inhibitor of nitric oxide(NO) synthase, or ODQ, an inhibitor of NO-sensitive guanylyl cyclase. L-NAME and ODQ showed no significant effect on the $PGE_1$-induced transient decrease of atrial dynamics. These data indicate that $PGE_1$ increases cGMP levels via NO-soluble GC signaling in the cardiac atrium and also show that $PGE_1$-induced increases in cGMP and cAMP levels are not involved in the regulation of atrial secretory and contractile functions.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.7
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• pp.697-703
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• 2006

Endocrine disruptors were measured with GC/MS in effluents discharged from sewage treatment processes in pilot scale for the purpose of water reuse. From that analysis, we compared the removal rate of them by treatment processes. Nonylphenol was mainly detected in effluents and high concentration from 0.36 to 0.94 ${\mu}g/L$. $17{\beta}$-estradiol(E2) and $17{\alpha}$-ethynylestradiol(EE2) were detected as below the limit of detection in effluent. Endocrine disruptors were removed effectively in the range from 50 to 100% by treatment process. EC50 value($9.0{\times}10^{-3}$ M) of $17{\beta}$-estradiol(E2) by dose response curve of E-screen assay has higher than that of bisphenol A($2.736{\times}10^{-5}M$) and p-octylphenol($9.760{\times}10^{-6}$ M). These results showed that alkylphenols have lower relative estrogen potency than other estrogens such as $17{\beta}$-estradiol(E2). Calculated estrogenic activity(ng-EEQ/L) was 2 times higher than measured total estrogenic activity which estimated by E-screen assay. Moreover estrogenic activity of effluent by treatment process showed very low as below 1 ng-EEQ/L.

• Proceedings of the Korean Biophysical Society Conference
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• 2003.06a
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• pp.23-23
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• 2003

It has been suggested that the impairment of smooth muscle cell (SMC) function by alterations in the $Ca^{2+}$-activated $K^{+}$ ( $K_{Ca}$ ) channels accounts for the reduction in coronary reserve during left ventricular hypertrophy (LVH). However, this hypothesis has not been fully investigated. The main goal of this study was to assess whether the properties of $K_{Ca}$ channels in coronary SMCs were altered during LVH. New Zealand white rabbits (0.8-1.0 kg) and Sprague-Dawley rats (300-400 g) were randomly selected to receive either an injection of isoproterenol (300 $\mu\textrm{g}$/kg body weight) or an equal volume of 0.9％ saline (1 mL/kg body weight). The animals developed LVH 10 days after injection. In patch-clamp experiments, the unitary current amplitude and open probability for the $K_{Ca}$ channels were significantly reduced in LVH patches compared with control patches. The concentration-response curve of the $K_{Ca}$ channel to [C $a^{2+}$]$_{i}$ was shifted to the right. Inhibition of the $K_{Ca}$ channels with TEA was more pronounced in LVH cells than in the control cells. The whole-cell currents of $K_{Ca}$ channels were reduced during LVH. Western blot analysis indicated no differences in $K_{Ca}$ channel expression between the control and LVH coronary SM membranes. In contraction experiments, the effect of a high $K^{+}$concentration on the resting tension of the LVH coronary artery was greater than on that of the control. The effect of TEA on the resting tension of the LVH coronary artery was reduced as compared with the effect on the control. Our findings imply a novel mechanism for reduced coronary reserve during LVH.ing LVH.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.11
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• pp.1607-1611
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• 2015

This study investigated the regulatory effects of African mango (Irvingia gabonesis, IGOB $131^{TM}$) extract on blood glucose level in streptozotocin (STZ)-induced diabetic rats. Experimental groups were treated with two different doses of IGOB $131^{TM}$ (1% and 2% in each AIN93G supplement) for 5 weeks [4 weeks pre-treatment and 1 week post-STZ treatment (60 mg/kg body weight)]. STZ-induced diabetic rats showed significantly reduced body weight gain compared to normal control (NC). Oral glucose tolerance test (OGTT) was measured using glucose oxidase-peroxidase reactive strips. The area of under the curve for the glucose response from OGTT in STZ-induced diabetic rats was higher than that of NC rats, and there was a significant difference between the DM and the IGOB $131^{TM}$-treated groups. Serum glucose levels after sacrifice were significantly lower in the IGOB $131^{TM}$ group than the DM group. However, there was no statistical difference between low- and high-dose treatments. Serum insulin levels increased by 234.4% and 175.9%, respectively, upon treatment with IGOB $131^{TM}$. Serum lipid profiles were not significantly different among the experimental groups. The tested samples had no effects on serum levels of lipid profiles (triglyceride, total cholesterol, low density lipoprotein/very low density lipoprotein-cholesterol, high density lipoprotein-cholesterol). These results suggest that IGOB $131^{TM}$ is able to ameliorate diabetes by reducing serum glucose levels that may result from increased insulin levels.

• Geophysics and Geophysical Exploration
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• v.9 no.4
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• pp.304-315
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• 2006

We have examined the applicability of f-k analysis to the GPR direct wave measurement for water content to characterize vadose zone condition. When the vadose zone consists of a dry surface layer over wet substratum, we obtained f-k spectra where most of the energy is bounded by the air and dry soil velocities. In this case, dry soil velocity was successfully estimated by using high frequency data. On the other hands, when wet soil overlies dry substratum, the f-k spectra show a contrasting response where most of the energy travels with the velocity bounded by dry and wet soil velocities. In this case, the radar waves are trapped and guided within wet soil layer, exhibiting velocity dispersion. By adopting modal propagation theory, we could formulae a simple inversion code to find two layer's dielectric constants as well as layer thickness. By inverting the velocity dispersion curve obtained from f-k spectra of synthetic modeling data, we could obtain good estimates of dielectric constants of each layer as well as first layer thickness. Moreover, we could obtain more accurate results by including the higher mode data. We expect this method will be useful to get the quantitative property of real subsurface when the field condition is similar.

• Archives of Pharmacal Research
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• v.23 no.4
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• pp.353-359
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• 2000

${\alpha}_2$-Adrenoceptor antagonists, which can enhance synaptic norepinephrine levels by blocking feedback inhibition processes, are potentially useful in the treatment of disease states such. as depression, memory impairment, impotence and sexual dysfunction. (10bS)-1,2,3,5,6,10b-Hexahydropyrrolo[2,1-a]isoquinoline oxalate (YSL-3S) was evaluated in several in vitro biological tests to establish its pharmacological profile of activities as an ${\alpha}_2$-adrenoceptor antagonist. Saturation binding assay revealed that$^{3}[H]$rauwolscine bound to the $\alpha$$_2$-adrenoceptors with a Kd value of 6.3$\pm$0.5 nM and a Bmax value of 25l$\pm$39 fmol/mg protein in rat cortical synaptic membranes. Competitive binding assay showed that YSL-3S inhibited the binding of$^3[H]$rauwolscine (1 nM) in a concentration-dependent manner with a Ki value of 98.2$\pm$12.1 nM while it did not inhibit the binding of [$^3$H]cytisine (1.25 nM) to neuronal nicotinic cholinergic receptors. The Ki values of yohimbine, clonidine and norepinephrine for $^3[H]$rauwolscine binding were 15.8$\pm$1.0, 40.1$\pm$5.9 and 40.0$\pm$11.5 nM, respectively. In addition, the binding affinity of YSL-3S for ${\alpha}_2$-adrenoceptors was higher than that of its antipode and the racemic mixture. The functional activity of YSL-3S at the presynaptic ${\alpha}_2$-adrenoceptors was assessed using the prostatic portion of the rat vas deferens. Clonidine inhibited field-stimulated contractions of the vas deference in a dose-dependent manner. The presence of YSL-3S or yohimbine caused a parallel, rightward the dose-response curve of clonidine in a dose-dependent manner, indicating an antagonistic action at the presynaptic ${\alpha}_2$-adrenoceptors. The $pA_2$values of yohimbine and YSL-3S were 7.66$\pm$0.13 and 6.64$\pm$0.18, respectively. The results indicate that YSL-3S acts as a competitive antagonist at presynaptic ${\alpha}_2$ -adrenoceptors with a potency approximately ten times lower than yohimbine, but is devoid of binding affinity for neuronal nicotinic cholinergic receptors.

• Journal of the Korean Chemical Society
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• v.44 no.6
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• pp.541-546
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• 2000

Methods to determine L-dopa(L-3,4-dihydroxyphenylalanine) in aqueous solution by spectrofluorimetry based upon the ligand sensitized luminescence of Tb(III) ion L-dopa complex have been studied. Tb(III) ion and Lu(III) ion were used as ligand sensitized fluorescencer and co-fluorescence enhancer, respectively. The effects of excitation wavelength, pH, concentration of Tb(III) ion, concentration of Lu(III) ion and emission wavelength on the fluorescence intensity were investigated. The fluorescence intensity of the Tb(III) ion L-dopa complex was further increased with addition of Lu(III) ion. The calibration curve for L-dopa was linear over the range from 5.0 ${\times}$ $10^{-7}$ M to 1.0${\times}$ $10^{-4}$ M and the detection limit was 4.0 ${\times}$ $10^{-8}$ M under the optimal experimental conditions of 300 nm, 8.0, 1.0 ${\times}$ $10^{-4}$ M and 545 nm for excitation wavelength, pH, concentration of Tb(III) ion and emission wavelength, respectively. When Lu(III) ion was added to Tb(Ⅲ) ion L-dopa complex, the concentration range of linear response and detection limit were 1.0${\times}$$10^{-8}$ M to 2.0 ${\times}$ $10^{-4}$ M and 1.0 ${\times}$ $10^{-9}$ M, respectively under the optimal experimental conditions of 300 nm, 8.5, 1.0 ${\times}$ $10^{-5}$ M, 1.0 ${\times}$ $10^{-5}$ M, 545 nm for excitation wavelength, pH, concentration of Tb(III) ion, concentration of Lu(III) ion and emission wavelength, respectively.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.2
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• pp.151-160
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• 2017

Growing demand and rapid development of the synthetic fiber rope in mooring system have taken place since it has been used in deep water platform lately. Unlike a chain mooring, synthetic fiber rope composed of lightweight materials such as Polyester(polyethylene terephthalate), HMPE(high modulus polyethylene) and Aramid(aromatic polyamide). Non-linear stiffness and another failure mode are distinct characteristics of synthetic fiber rope when compared to mooring chain. When these ropes are exposed to environmental load for a long time, the length of rope will be increased permanently. This is called 'the creep phenomenon'. Due to the phenomenon, The initial characteristics of mooring systems would be changed because the length and stiffness of the rope have been changed as time goes on. The changed characteristics of fiber rope cause different mooring tension and vessel offset compared to the initial design condition. Commercial mooring analysis software that widely used in industries is unable to take into account this phenomenon automatically. Even though the American Petroleum Institute (API) or other classification rules present some standard or criteria with respect to length and stiffness of a mooring line, simulation guide considers the mechanical properties that is not mentioned in such rules. In this paper, the effect of creep phenomenon in the fiber rope mooring system under specific environment condition is investigated. Desiged mooring system for a Mobile Offshore Drilling Unit(MODU) with HMPE rope which has the highest creep is analyzed in a time domain in order to investigate the effects creep phenomenon to vessel offset and mooring tension. We have developed a new procedure to an analysis of mooring system reflecting the creep phenomenon and it is validated through a time domain simulation using non-linear mooring analysis software, OrcaFlex. The result shows that the creep phenomenon should be considered in analysis procedure because it affects the length and stiffness of synthetic fiber rope in case of high water temperature and permanent mooring system.

• Journal of Life Science
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• v.26 no.8
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• pp.921-927
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• 2016

Postprandial hyperglycemia is an early defect of type 2 diabetes and one of primary anti-diabetic targets. The alpha-glucosidase inhibitors regulate postprandial hyperglycemia by impeding the rate of carbohydrate (such as starch) digestion in the small intestine. This study was designed to investigate the inhibitory actions of mulberry fruit extract (MFE) on α-glucosidase and α-amylase activities, and its alleviating effect on postprandial hyperglycemia activities in vitro and in vivo. Male four-week old ICR mice and streptozotocin (STZ)-induced diabetic mice were treated with mulberry fruit extract. MFE showed strong inhibitory effects against α-glucosidase and α-amylase activities, with half-maximal inhibitory concentration (IC₅₀) values of 0.16 and 0.14 mg/ml, respectively, and was more effective than acarbose, which was used as a positive control. The increase in postprandial blood glucose levels was more significantly attenuated in the MFE-administered group mice than in the control group mice of both STZ-induced diabetic and normal mice. Moreover, the area under the glucose response curve significantly decreased following MFE administration in diabetic mice. These results indicate that MFE may be a potent inhibitor of α-glucosidase and α-amylase, and helpful in suppressing postprandial hyperglycemia in diabetic mice. The mulberry fruit extracts may be considered as a potential candidate for the management of diabetes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.7
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• pp.3207-3213
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• 2011

Most methods of color constancy, which is the ability to determine the object color regardless of the scene illuminant, have failed to meet our expectation of their performance especially about low-illuminated scenes. Some methods with high performance need to be developed, but we must, above all else, obtain experimental images for analyzing the required circumstances or evaluating the methods. Therefore, the paper produces new sets of images so that they can be used in the development of color constancy methods suitable for low-illuminated scenes. These sets are composed of two parts: one part of images which are synthesized with spectral power distribution(SPD) of illuminants, spectral reflectance curve of reflectances, and sensor response functions of camera; the other part of images where the intensity of each image is adjusted at the uniform rate. In an experiment, the use of the sets takes an advantage that its result images are analyzed and evaluated quantitatively as their ground truth data are known in advance.