• 대한수의학회지
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• 제40권3호
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• pp.479-487
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• 2000

Several recent studies demonstrate that receptor-mediated cAMP (adenosine 3',5'-monophosphate) production evokes marked change in magnesium ($Mg^{2+}$) homeostasis. The effects of dimaprit or/and phosphodiesterase (PDE) inhibitors on the $Mg^{2+}$ release from perfused guinea pig heart and collagenase-dispersed myocytes was studied to clarify an association of $H_2-histaminergic$ receptor-mediated $Mg^{2+}$ regulation with intracellular cAMP-degradation system. $Mg^{2+}$ efflux was stimulated in perfused hearts and myocytes by IBMX (3-isobutyl-1-methylxanthine), a calmodulin-sensitive PDE inhibitor, but not by RO 20-1724(4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone) or papaverine, cAMP-specific PDE inhibitors. $Mg^{2+}$ efflux was also be induced by dimaprit, a H-2-agonist. $Mg^{2+}$ effluxes induced by dimaprit were augmented by the presence of the PDE inhibitors. The augmentation of dimaprit-induced $Mg^{2+}$ effluxes by the PDE inhibitors were inhibited by ranitidine, a $H_2-antagonist$, and imipramine, a $Na^{+}-Mg^{2+}$ exchange inhibitor, in perfused hearts and myocytes and were also inhibited by amiloride in perfused hearts. These results suggest that the $H_2$-stimulated $Mg^{2+}$ effluxes from guinea pig heart can be regulated by the cytosolic nonspecific-dependent PDE systems and that it is induced by the $Na^{+}-Mg^{2+}$ exchanger stimulation.

• Biomolecules & Therapeutics
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• 제13권1호
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• pp.20-25
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• 2005

The present study was performed to evaluate antiarrhythmic effects of KR-32570, a novel inhibitor of sodium hydrogen exchanger subtype-1 (NHE-1), in rat arrhythmia induced by focal ischemia and reperfusion. During ischemia, KR-32570 significantly decreased the number of premature ventricular contraction (PVC) from 152.0 times to 75.5, 52.4 and 20.0 times for 0.1, 0.3 and 1.0 mg/kg, respectively (p<0.05) and the duration of ventricular tachycardia (VT) from 88.1 s to 35.8, 7.7 and 1.3 s, respectively(p<0.05) in anesthetized rats subjected to 10-min coronary occlusion of coronary artery. Similarlt to ischemia-induced arrhythmia, KR-32570 significantly decreased reperfusion-induced arrhythmia including PVC (41.3, 21.5, 11.3 and 6.6 times at vehicle, 0.1, 0.3 and 1.0 mg/kg, respectively, p<0.05) and VT (100.5, 64.2, 25.8 and 25.2 s, respectively, p<0.05), and VF (86.9, 27.5, 6.9 and 0 s, respectively, p<0.05). Moreover, KR-32570 dose-dependently decreased the incidence of mortality occurring after reperfusion (41, 27, 18 and 0% at vehicle, 0.1, 0.3, 1.0 mg/kg, respectively). These results suggest that KR-32570 has a potent antiarrhythmic effect in rat arrhythmia induced by ischemia and reperfusion.

• Nuclear Engineering and Technology
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• 제56권3호
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• pp.893-899
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• 2024

In a secondary cooling system of a sodium-cooled fast reactor (SFR), rapid detection of hydrogen due to sodium-water reaction (SWR) caused by water leakage from a heat exchanger tube of a steam generator (SG) is important in terms of safety and property protection of the SFR. For hydrogen detection, the hydrogen detectors using atomic transmission phenomenon of hydrogen within Ni-membrane were used in Japanese proto-type SFR "Monju". However, during the plant operation, detection signals of water leakage were observed even in the situation without SWR concerning temperature up and down in the cooling system. For this reason, the study of a new hydrogen detector has been carried out to improve stability, accuracy and reliability. In this research, the authors focus on the difference in composition of hydrogen and the difference between the background hydrogen under normal plant operation and the one generated by SWR and theoretically estimate the hydrogen behavior in liquid sodium by using ultra-accelerated quantum chemical molecular dynamics (UA-QCMD). Based on the estimation, dissolved H or NaH, rather than molecular hydrogen (H₂), is the predominant form of the background hydrogen in liquid sodium in terms of energetical stability. On the other hand, it was found that hydrogen molecules produced by the sodium-water reaction can exist stably as a form of a fine bubble concerning some confinement mechanism such as a NaH layer on their surface. At the same time, we observed experimentally that the fine H₂ bubbles exist stably in the liquid sodium, longer than previously expected. This paper describes the comparison between the theoretical estimation and experimental results based on hydrogen form in sodium in the development of the new hydrogen detector in Japan.

• Molecules and Cells
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• 제40권8호
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• pp.567-576
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• 2017

The $Na^+/H^+$ exchanger is responsible for maintaining the acidic tumor microenvironment through its promotion of the reabsorption of extracellular $Na^+$ and the extrusion of intracellular $H^+$. The resultant increase in the extracellular acidity contributes to the chemoresistance of malignant tumors. In this study, the chemosensitizing effects of cariporide, a potent $Na^+/H^+-exchange$ inhibitor, were evaluated in human malignant mesothelioma H-2452 cells preadapted with lactic acid. A higher basal level of phosphorylated (p)-AKT protein was found in the acid-tolerable H-2452AcT cells compared with their parental acid-sensitive H-2452 cells. When introduced in H-2452AcT cells with a concentration that shows only a slight toxicity in H-2452 cells, cariporide exhibited growth-suppressive and apoptosis-promoting activities, as demonstrated by an increase in the cells with pyknotic and fragmented nuclei, annexin V-PE(+) staining, a $sub-G_0/G_1$ peak, and a $G_2/M$ phase-transition delay in the cell cycle. Preceding these changes, a cariporide-induced p-AKT down-regulation, a p53 up-regulation, an ROS accumulation, and the depolarization of the mitochondrial-membrane potential were observed. A pretreatment with the phosphatidylinositol-3-kinase (PI3K) inhibitor LY294002 markedly augmented the DNA damage caused by the cariporide, as indicated by a much greater extent of comet tails and a tail moment with increased levels of the p-histone H2A.X, $p-ATM^{Ser1981}$, $p-ATR^{Ser428}$, $p-CHK1^{Ser345}$, and $p-CHK2^{Thr68}$, as well as a series of pro-apoptotic events. The data suggest that an inhibition of the PI3K/AKT signaling is necessary to enhance the cytotoxicity toward the acidtolerable H-2452AcT cells, and it underlines the significance of proton-pump targeting as a potential therapeutic strategy to overcome the acidic-microenvironment-associated chemotherapeutic resistance.

• KSBB Journal
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• 제16권6호
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• pp.533-537
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• 2001

유청 단백질 중에서 $\alpha$-lactalbumin, $\beta$-lactoglobulin를 고성능 막 크로마코그래피를 이용하여 분리하는 것이다. 분리 메카니즘은 음이온 교환작용이며 고정상은 CIM DEAE, QA, So$_3$ disk (16$\times$3 mm)을 사용하였다. 이동상은 buffer A (20 mM Tris-HCI, pH 7.3)와 buffer B (buffer A + 1 M NaCl)를 사용하였으며 $\alpha$-lactalbumin, $\beta$-lactoglobulin를 분리하기 위해서 구배용매 조성법을 사용하였다. 각 이동상의 조성에 따른 최적의 이동상 조성(Buffer A/Buffer B=100/0 - 30/70 vol%, gradient time 1 min, 30/70 - 10/90 vol%, gradient time 2 min)을 실험적으로 얻었고 4 ml/min의 이동상 유속에서 3분내에 $\alpha$-lactalbumin, $\beta$-lactoglobulin를 분리 할 수 있었다. 유청 단백질 중에 $\alpha$-lactalbumin, $\beta$-lactoglobulin을 HPMC을 적용하여 분리하였고, 유청 단백질의 기능적 성질, 분리 방법에 대해 알아보았다.

• The Korean Journal of Physiology and Pharmacology
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• 제22권3호
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• pp.269-275
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• 2018

$Na^+/H^+$ exchangers (NHEs) have been shown to be involved in regulating cell volume and maintaining fluid and electrolyte homeostasis. Pooled evidences have suggested that loss of $Na^+/H^+$ exchanger isoform 8 (NHE8) impairs intestinal mucosa. Whether NHE8 participates in the pathology of infectious colitis is still unknown. Our previous study demonstrated that somatostatin (SST) could stimulate the expression of intestinal NHE8 so as to facilitate $Na^+$ absorption under normal condition. This study further explored whether NHE8 participates in the pathological processes of infectious colitis and the effects of SST on intestinal NHE8 expression in the setting of infectious colitis. Our data showed that NHE8 expression was reduced in Citrobacter rodentium (CR) infected mice. Up-regulation of NHE8 improved diarrhea symptom and mucosal damage induced by CR. In vitro, a similar observation was also seen in Enteropathogenic E. coli (EPEC) infected Caco-2 cells. Seglitide, a SST receptor (SSTR) 2 agonist, partly reversed the inhibiting action of EPEC on NHE8 expression, but SSTR5 agonist (L-817,818) had no effect on the expression of NHE8. Moreover, SST blocked the phosphorylation of p38 in EPEC-infected Caco-2 cells. Taken together, these results suggest that enhancement of intestinal NHE8 expression by SST could ameliorate the symptoms of mice with infectious colitis.

• Journal of Applied Biological Chemistry
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• 제48권1호
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• pp.1-6
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• 2005

Analysis of chlorophyll (Chl) fluorescence implicated treatment of 40 mM NaCl decreased maximal photochemical efficiency of photosystem II (PSII) (Fv/Fm), actual quantum yield of PSII (${\Phi}_{PSII}$), and photochemical quenching (qP) in rice, but increased non-photochemical quenching (NPQ). Decreases in Fv/Fm, ${\Phi}_{PSII}$, and qP were significantly alleviated by $30\;{\mu}M$ jasmonic acid (JA), while NPQ increase was enhanced. Transcription levels of antioxidant isoenzyme genes were differentially modulated by NaCl treatment. Expression of cCuZn-SOD2 gene increased, while those of cAPXb, CATb, and CATc genes decreased. JA prevented salt-induced decrease of pCuZn-SOD gene expression, but caused greater decrease in mRNA levels of cAPXa and Chl_tAPX genes. Investigation of vacuolar $Na^+/H^+$ exchanger (NHX2) and 1-pyrroline-5-carboxylate synthetase (P5CS) gene expressions revealed transcription level of NHX2 gene was increased by JA, regardless of NaCl presence, while that of P5CS gene slightly increased only in co-presence of JA and NaCl. Unlike JA, ${\gamma}$-radiation rarely affected expressions of antioxidant isoenzyme, NHX2, and P5CS genes, except for increase in mRNA level of Chl_tAPX and decrease in that of pCuZn-SOD. These results demonstrate enhanced salt-tolerance in JA-treated rice seedlings may be partly due to high transcription levels of pCuZn-SOD, NHX2, and P5CS genes under salt stress.

• 한국산업보건학회지
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• 제1권2호
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• pp.214-220
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• 1991

As chromium in urine remains as oxychromic acid ions, chromium was extracted by using ion pair formed by anion exchanger trioctylamine. then after it is noted whether this TOA-MIBK method is effective or not for the chromium analysis by using flame method of Atomic absorption Spectrophotometric Analysis. The result is as following. 1. Effects of various acids on the extraction of Cr with MIBK including TOA are good in order $NHO_3$, $H_2SO_4$, HCl in distilled water sample and its proper concentration of HCl is 0.2 N. 2. For the analysis of urine sample, the best result can be achieved by following condition. After finished pretreatment adjusted to pH 6.5-7.5 by NaOH and again controlled pH 0.5-0.6 by HCl. 3. Though TOA concentration slightly affects the analytic value, best result is noted in 1-3% concentration. 4. Recovery rates of urine samples made by $0.3mg/l{\cdot}urine$, $0.6mg/l{\cdot}urine$, $0.9mg/l{\cdot}urine$ are shown from 96.7% to 104.8%. 5. Recovery rates of urine samples made by $0.01mg/l{\cdot}urine$, $10.03mg/{\cdot}urine$, $0.05mg/l{\cdot}urine$ are shown from 89.3% to 98.6%.

• KSBB Journal
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• 제11권5호
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• pp.606-612
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• 1996

H형 Dowex 50W-X8 강산성 양이온 교환수지 결럼을 이용하여 glutamic acid를 치환전개하면셔 displacer의 농도를 증가시켜 인위적으로 결정화를 유도하였다. Displacer로 사용한 NaOH 놓도를 증 가시킴으로써 glutamic acid가 그 용해도 한계 이상 으로 농축되면서 컬럼내에서 이동도중 결정층이 형 성되었고 생성된 결정은 effluent stream을 따라 fraction collector로 회수되어졌다. 결정충이 이동하는 동안 clogging이나 압력강하의 문제점이 발생 하지 않았으며 1.0 M NaOH를 사용할 때 62% 의 glutamic acid가 결정으로 회수되었다. 수지로부터 치환되 어 나오는 $H^+$에 의한 OH 의 중화작용으로 인해 NaCI 보다는 NaOH가 효과적인 displacer임 을 알 수 있었으며 보다 sharp하고 농축된 band를 얻을 수 있었다 Glutamic acid 결정층의 이동속도 는 displacer 이통속도와 통일하였는데 그 이유는 결정이 이동하는 기작이 고정상의 interstitial fluid를 따라 이통하는 것이 아니라 일정한 두께의 결정층이 형성된 뒤에 앞경계변에셔는 계속 새로운 결정화가, 그리고 뒷경계변에서는 기존결정의 재용해가 일어나 면서 컬럼을 이동하는 것이며 또한 이 결정화 속도 와 재용해 속도가 비슷하게 균형을 이루고 있기 때 문이라고 설명할 수 있다. 이와 같은 이온교환중의 결정화 현상은 수지에 대한 선택도와 함께 용해도라 는 부가적 분리 인자를 통시에 사용함으로써 특정성 분의 분리효율을 높일 수 있으며 이온교환 후 추가 로 거쳐야 할 결정화 콩정의 부담을 줄일 수 있을 것이다. 결정화-재용해가 비슷한 속도로 반복되는 이통결정층이 형성된다는 관찰은 본 실험에서 사용 된 glutamic acid에만 적용할 수 있는 특이한 현상 일 수 있으며 aspartic acid 등 다른 저용해도 아미 노산에도 일반화할 수 있는 현상인지를 밝허가 위해 서는 보충 연구가 펄요하다. 더우기 이러한 결정화 현상은 단순히 용질의 용해도와 displacer 농도뿐만 아니라 pH, ionic strength, 사용하는 수지의 가교 도, mobile phase의 유속, 사용하는 컬럼의 제원에 도 영향을 받을 것이라고 사료되므로 결정회수율을 극대화하기 위한 최적조건의 도출 빛 그 적용범위의 확대에 대한 연구가 필요하다.

• 공업화학
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• 제10권5호
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• pp.666-671
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• 1999

본 연구에서 술폰화된 poly(phenylene sulfide)(SPPS)는 10%의 발연황산으로 PPST를 술폰화한 후 NaOH 수용액으로 demethylation하여 제조하였다. 유기용매에 용해되는 PPST는 methyl-(phenylthio)phenyl sulfoxide(MPPSO)의 자가축합 반응으로 합성되었다. SPPS는 $1200cm^{-1}$에서 $-SO_{3}H$의 비대칭 O=S=O 신축진동에 의한 흡수피크와 $621cm^{-1}$에서 S-O 신축진동에 의한 흡수피크가 관찰된 것으로 보아 술폰산기가 도입된 것을 알 수 있다. PPST의 술폰화를 $150^{\circ}C$에서 12시간 반응했을 때 반복단위당 1.48개의 술폰산기가 도입되었으며, 고온 GPC로 측정된 PPST와 SPPS의 중량평균분자량(Mw)은 각각 118323과 131204이었다. SPPS의 암모니아 가스 흡착능은 $9.67mmol\;NH_{3}/g$이었고, 활성탄, 실리카겔보다 월등히 높았다.