• 대한수의학회지
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• 제59권2호
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• pp.59-67
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• 2019

We investigated whether ${\beta}$-carotene (${\beta}-CA$) or ellagic acid (EA), originating from various fruits and vegetables, has a preventive effect against male infertility induced by exogenous scrotal hyperthermia. ICR adult mice were intraperitoneally treated with 10 mg/kg of ${\beta}-CA$ or EA daily for 13 days consecutively. During this time, mice were subjected to transient scrotal heat stress in a water bath at $43^{\circ}C$ for 20 min on day 7, and their testes and blood were obtained on day 14 for histopathologic and biochemical analyses. Heat stress induced significant testicular weight reduction, germ cell loss and degeneration, as well as abnormal localization of phospholipid hydroperoxide glutathione peroxidase (PHGPx) and manganese superoxide dismutase (MnSOD) in spermatogenic and Leydig cells. Heat stress also altered the levels of oxidative stress (lipid peroxidation, SOD activity, and PHGPx, MnSOD, and $HIF-1{\alpha}$ mRNAs), apoptosis (Bax, Bcl-xL, caspase 3, $NF-{\kappa}B$, and $TGF-{\beta}1$ mRNAs), and androgen biosynthesis (serological testosterone concentration and $3{\beta}$-hydroxysteroid dehydrogenase mRNA) in testes. These changes were all improved significantly by ${\beta}-CA$ treatment, but only slightly improved by EA treatment. These findings indicate that ${\beta}-CA$, through modulations of oxidative stress, apoptosis, and androgen biosynthesis, is a potent preventive agent against testicular injuries induced by scrotal hyperthermia.

• 대한수의학회지
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• 제29권3호
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• pp.245-251
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• 1989

In order to manifest the presence of Na-K pump and its property on the unfertilized egg membranes of mouse, membrane potential was recorded under the physiological condition (at $37^{\circ}C$ and 4mM $Ca^{2+}$). After an induction of superovulation, the fresh eggs with zona pellucida were collected from mouse oviduct. Transient hyperpolarization as pump action was recorded after the switch into the high potassium perfusate (15mM $K^+$) from K-free perfusate, and the difference between membrane potential observed just before the perfusion of high potassium solution and the maximal membrane potenlial during the perfusion of high potassium solution was regard as pump activities. The results observed were as follows, 1. Resting mombrane potential was depolarized under the treatment of $10^{-5}M$ ouabain. 2. Pump activities of the unfertilized mouse eggs were $-3.38{\pm}0.61mV$ ($Mean{\pm}SD$, n=6), recorded as transient hyperpolarization due to the electrogenic property. 3. Pump activities were blocked by both treatment of $10^{-5}M$ ouabain and perfusion of Nafree solution, while increased by high $Na^+$ (300mM) perfusion ($-7.45{\pm}0.75mV$, n =2). 4. Hyperpolarization due to pump activity was not altered by $Mn^{2+}$. 5. Above results confirm the presence of ouabain-sensitive Na-K pump, which affected the membrane potential directly, on the unfertilized egg membranes of mouse.

• Natural Product Sciences
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• 제15권4호
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• pp.198-202
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• 2009

Based on the use of Acorus gramineus SOLAND (AG) for the treatment of stroke in traditional Korean medicine, the present study was carried out to evaluate neuroprotective effects of ${\alpha}$-asarone after transient global cerebral ischemia using rat 4-vessel occlusion (4VO) model in rats. ${\alpha}$-Asarone (5 mg/kg) administered intraperitoneally significantly protected CA1 neurons against 10 min transient forebrain ischemia as demonstrated by measuring the density of neuronal cells stained with Cresyl violet. ${\alpha}$-Asarone significantly reduced hippocampal neuronal cell death by 85.2% where as its isolated single compounds from AG compared with a vehicle-treated group.

• The Korean Journal of Physiology and Pharmacology
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• 제21권1호
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• pp.133-140
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• 2017

Conflicting evidence has been obtained regarding whether transient receptor potential cation channels (TRPC) are store-operated channels (SOCs) or receptor-operated channels (ROCs). Moreover, the Ca/Na permeability ratio differs depending on whether the current-voltage (I-V) curve has a doubly rectifying shape or inward rectifying shape. To investigate the calcium permeability of TRPC4 channels, we attached GCaMP6s to TRPC4 and simultaneously measured the current and calcium signals. A TRPC4 specific activator, (-)-englerin A, induced both current and calcium fluorescence with the similar time course. Muscarinic receptor stimulator, carbachol, also induced both current and calcium fluorescence with the similar time course. By forming heteromers with TRPC4, TRPC1 significantly reduced the inward current with outward rectifying I-V curve, which also caused the decrease of calcium fluorescence intensity. These results suggest that GCaMP6s attached to TRPC4 can detect slight calcium changes near TRPC4 channels. Consequently, TRPC4-GCaMP6s can be a useful tool for testing the calcium permeability of TRPC4 channels.

• 대한수의학회지
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• 제34권1호
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• pp.25-36
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• 1994

The inward tail current after a short depolarizing pulse has been known as Na-Ca exchange current activated by intracellular calcium which forms late plateau of the action potential in rabbit atrial myocytes. Chloride conductance which is also dependent upon calcium concentration has been reported as a possible tail current in many other excitable tissues. Thus, in order to investigate the exsitance of the calcium activated chloride current and its contribution to tail current, whole cell voltage clamp measurement has been made in single atrial cells of the rabbit. The current was recorded during repolarization following a brief 2 ms depolarizing pulse to +40mV from a holding potential of -70mV. When voltage-sensitive transient outward current was blocked by 2 mM 4-aminopyridine or replacement potassium with cesium, the tail current were abolished by ryanodine$(1{\mu}M)$ or diltiazem$(10{\mu}M)$ and turned out to be calcium dependent. The magnitudes of the tail currents were increased when intracellular chloride concentration was increased to 131 mM from 21 mM. The current was decreased by extracellular sodium reduction when intracellular chloride concentration was low(21 mM), but it was little affected by extracellular sodium reduction when intracellual chloride concentration was high(131 mM). The current-voltage relationship of the difference current before and after extracellular sodium reduction, shows an exponential voltage dependence with the largest magnitude of the current occurring at negative potentials, with is similar to current-voltage relationship at negative potentials, which is similar to current-voltage relationship of Na-Ca exchange current. The current was also decreased by $10{\mu}M$ niflumic acid and 1 mM bumetanide, which is well known anion channel blockers. The reversal potentials shifted according to changes in chloride concentration. The current-voltage relationships of the niflumic acid-sensitive currents in high and low concentration of chloride were well fitted to those predicted as chloride current. From the above results, it is concluded that calcium activated chloride component exists in the tail current with Na-Ca exchange current and it shows the reversal of tail current. Therefore it is thought that in the physiologic condition it leads to rapid end of action potential which inhibits calcium influx and it contributes to maintain the low intracellular calcium concentration with Na-Ca exchange mechanism.

• Korean Chemical Engineering Research
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• 제51권1호
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• pp.136-143
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• 2013

본 연구에서는 악취 및 휘발성 유기화합물(VOC)를 함유하는 폐가스 처리에 있어서 개선된 바이오필터시스템의 악취 및 VOC의 제거거동 및 제거효율 등을 관찰하고, 전통적 바이오필터의 경우의 악취 및 VOC의 제거거동 및 제거효율 등과 비교하였다. 개선된 바이오필터시스템 운전 1~7단계에서 바이오필터 유효높이 차이에도 불구하고 미생물 population 분포 차이로 인하여, 정해진 시간에 각 단에서 에탄올 농도 순서가 바뀌었다. 반면에 운전 8단계에서 폐가스의 개선된 바이오필터시스템으로의 공급방향들이 바뀌었을 때에 에탄올 농도가 높은 순서는 운전 1~7단계와 다르게 바이오필터의 유효높이가 낮은 순서와 일치하였다. 황화수소 경우도 마찬가지였으나 에탄올 경우와 비교하였을 때에 농도순서가 바뀐 단의 황화수소 농도의 차이는 매우 적었다. 바이오필터 운전 8단계에서 개선된 바이오필터시스템의 에탄올 제거효율은 약 96%로서 전통적 바이오필터반응기의 에탄올 제거효율인 94%보다 약 2% 증가하였다. 개선된 바이오필터시스템 처리가스의 황화수소 농도의 거동은 전통적 바이오필터반응기와 비슷하였으나 황화수소 처리농도가 더 낮았다. 운전 8단계의 개선된 바이오필터시스템의 황화수소제거효율은 전통적 바이오필터반응기의 황화수소 제거효율보다 약 2% 가량 높았다. 따라서 개선된 바이오필터시스템의 제거효율은 에탄올과 황화수소 경우에 전통적 바이오필터반응기보다 각각 2% 제고되었음이 관찰되었다.

• The Korean Journal of Physiology and Pharmacology
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• 제15권1호
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• pp.61-66
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• 2011

P2Y receptors are metabotropic G-protein-coupled receptors, which are involved in many important biologic functions in the central nervous system including retina. Subtypes of P2Y receptors in retinal tissue vary according to the species and the cell types. We examined the molecular and pharmacologic profiles of P2Y purinoceptors in retinoblastoma cell, which has not been identified yet. To achieve this goal, we used $Ca^{2+}$ imaging technique and western blot analysis in WERI-Rb-1 cell, a human retinoblastoma cell line. ATP ($10\;{\mu}M$) elicited strong but transient $[Ca^{2+}]_i$ increase in a concentration dependent manner from more than 80% of the WERI-Rb-1 cells (n=46). Orders of potency of P2Y agonists in evoking $[Ca^{2+}]_i$ transients were 2MeS-ATP>ATP>>UTP=${\alpha}{\beta}$-MeATP, which was compatible with the subclass of $P2Y_1$ receptor. The $[Ca^{2+}]_i$ transients evoked by applications of 2MeS-ATP and/or ATP were also profoundly suppressed in the presence of $P2Y_1$ selective blocker (MRS 2179; $30\;{\mu}M$). $P2Y_1$ receptor expression in WERI-Rb-1 cells was also identified by using western blot. Taken together, $P2Y_1$ receptor is mainly expressed in a retinoblastoma cell, which elicits $Ca^{2+}$ release from internal $Ca^{2+}$ storage sites via the phospholipase C-mediated pathway. $P2Y_1$ receptor activation in retinoblastoma cell could be a useful model to investigate the role of purinergic $[Ca^{2+}]_i$ signaling in neural tissue as well as to find a novel therapeutic target to this lethal cancer.

• The Korean Journal of Physiology
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• 제22권1호
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• pp.13-29
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• 1988

In order to elucidate the regulatory mechanism of intracellular calcium ion concentrations, contractions or contractures induced by $Na^{+}-removal$, calcium-application or ouabain-treatment as an index of $Na^+/Ca^{2+}$ exchange activity were studied in atrial muscle or vascular smooth muscle (aorta and renal artery) of the rabbit. The magnitude of low sodium contractures in atrial trabeculae increased with sigmoid shape when external sodium concentrations were reduced to sodium-free condition, whereas that of calcium contracture intensified in a parabolic pattern when external calcium concentrations were elevated to 8 mM. $Na^{+}-removal$ contractures were induced in a duration-dependent manner to $K^{+}-free$ exposure and same findings were observed with ouabain treatment. $Na^{+}-free$ contractures were not affected by verapamil treatment, but stimulated by $100{\mu}M\;Mn^{2+}$ and inhibited by high concentrations of $Mn^{2+}\;(2{\sim}8mM)$ in a dose-dependent manner. Ryanodine which is known to suppress the release of calcium from internal store abolished spontaneous twitch contractions induced by $K^{+}-free$ solution, but had no effect on the development $Na^{+}-free$ contractures. Na-free contractures were not always induced in vascular smooth muscle preparations. Contractures by $O\;mM\;Na^+$ were usually seen in aorta, but not often in renal artery.$50\;mM\;K^+$, noradrenaline (NA) and angiotensin II (AII) always evoked very large contraction in all preparations of vascular smooth muscle. Contractures developed by $O\;mM\;Na^+$ were not sensitive to verapamil treatment as in atrial trabeculae, but were abolished by $100{\mu}M\;Mn^{2+}$. In contrast to $Na^{+}-free$ contractures, $Mn^{2+}(100{\mu}M)$ had no effect on the contractures induced by NA or 50 mM$K^+$. Caffeine in the concentration of 10 mM evoked transient contracture in the distal renal artery. The rate of spontaneous relaxation in caffeine contracture was dependent upon the concentrations of external sodium, and had double component of relaxation when the rate of relaxation was plotted in the semilogarithmic scale of relative tension versus time. Especially late components of relaxation had more direct relation to $Na^+$ concentrations. It could be concluded that $Na^+/Ca^{2+}$ exchange mechanism in the heart has a large capacity, inhibited by $Mn^{2+}$ but not by verapamil and ryanodine, while $Na^+/Ca^{2+}$ exchange system in vascular smooth muscle has a very low capacity especially in small artery, inhibited by low concentration of $Mn^{2+}\;(100{\mu}M)$ but not affected by verapamil and ryanodine.

• 한국재료학회지
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• 제30권7호
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• pp.343-349
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• 2020

NKN [(Na,K)NbO₃] is a candidate lead-free piezoelectric material to replace PZT [Pb(Zr,Ti)O₃]. A single crystal has excellent piezoelectric-properties and its properties are dependent of the crystal orientation direction. However, it is hard to fabricate a single crystal with stoichiometrically stable composition due to volatilization of sodium during the growth process. To solve this problem, a solid solution composition is designed (Na,K)NbO₃-Ba(Cu,Nb)O₃ and solid state grain growth is studied for a sizable single crystal. Ceramic powders of (Na,K)NbO₃-M(Cu,Nb)O₃ (M = Ca, Sr, Ba) are synthesized and grain growth behavior is investigated for different temperatures and times. Average normal grain sizes of individual specimens, which are heat-treated at 1,125 ℃ for 10 h, are 6.9, 2.8, and 1.6 ㎛ for M = Ca, Sr, and Ba, respectively. Depending on M, the distortion of NKN structure can be altered. XRD results show that (NKN-CaCuN: shrunken orthorhombic; NKN-SrCuN: orthorhombic; NKN-BaCuN: cubic). For the sample heat-treated at 1,125 ℃ for 10 h, the maximum grain sizes of individual specimens are measured as 40, 5, and 4,000 ㎛ for M = Ca, Sr, and Ba, respectively. This abnormal grain size is related to the partial melting temperature (NKN-CaCuN: 960 ℃; NKN-SrCuN: 971 ℃; NKN-BaCuN: 945 ℃).

• Molecules and Cells
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• 제26권5호
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• pp.474-480
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• 2008

OsMADS1 is a rice MADS box gene necessary for floral development. To identify the key cis-regulatory regions for its expression, we utilized transgenic rice plants expressing GUS fusion constructs. Histochemical analysis revealed that the 5.7-kb OsMADS1 intragenic sequences, encompassing exon 1, intron 1, and a part of exon 2, together with the 1.9-kb 5' upstream promoter region, are required for the GUS expression pattern that coincides with flower-preferential expression of OsMADS1. In contrast, the 5' upstream promoter sequence lacking this intragenic region caused ectopic expression of the reporter gene in both vegetative and reproductive tissues. Notably, incorporation of the intragenic region into the CaMV35S promoter directed the GUS expression pattern similar to that of the endogenous spatial expression of OsMADS1 in flowers. In addition, our transient gene expression assay revealed that the large first intron following the CaMV35S minimal promoter enhances flower-preferential expression of GUS. These results suggest that the OsMADS1 intragenic sequence, largely intron 1, contains a key regulatory region(s) essential for expression.