• The Journal of Korean Academy of Prosthodontics
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• v.15 no.1
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• pp.43-47
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• 1977

The purpose of this study was to determine human pulp reactions to temporary cements such as zinc oxide-eugenol cement, modified zinc oxide-eugenol cement (Cavitec) and calcium hydroxide cement (Dycal). Deep class V cavities were prepared in the human teeth with ultrahigh-speed handpiece operating at a free running speed of 300,000 r.p.m., using # 701 bur and water spray coolant. The cavities were flushed with water, dried with cotton pellets and filled with zinc oxide-eugenol cement, modified zinc oxide-eugenol cement and calcium hydroxide cement respectively. The teeth were divided into two groups, which one group was extracted after One day and the other was extracted after seven days. The samples were examined with microscope and the findings were as follows; 1. The pulp reactions to temporary cements were generally mild. Among them the reactions were moderate in zinc oxide-eugenol cement and, slight in calcium hydroxide cement. 2. Calcium hydroxide cement may be used properly as temporary cement for the purpose of pulp protection.

• The Korean Journal of Physiology
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• v.26 no.2
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• pp.123-128
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• 1992

The present study was undertaken to examine if endogenous nitric oxide is partly responsible for the high calcium induced vasorelaxation in vitro. Isolated porcine coronary arterial rings were suspended in the tissue chamber and their changes in isometric tension were recorded. KCI little affected the vascular tension in the calcium free media, but subsequent addition of cumulative doses of $CaCl_3$ from 1 to 40 mM caused a contraction followed by complete relaxation. The maximum tension was noted at the calcium concentration in the media of 5 mM, and then the tension progressively declined at 10-40 mM. The relaxation was slightly attenuated in the endothelium-denuded preparation. The relaxation was converted into a contraction by the addition of methylene blue. The relaxation response was not affected in the presence of indomethacin, but was significantly attenuated by $N^w-nitro-L-arginine$ methyl ester pretreatment. These results suggest that the calcium induced vasorelaxation is in part attributable to the release of endogenous nitric oxide.

• BMB Reports
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• v.31 no.5
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• pp.468-474
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• 1998

Membrane depolarization in PC12 cells induces calcium influx via an L-type voltage-sensitive calcium channel (L-VSCC) and increases intracellular free calcium, which leads to tyrosine phosphorylation of epidermal growth factor (EGF) receptor and the associated adaptor protein, She. This activated EGF receptor complex then can activate mitogen-activated protein (MAP) kinase, as in nerve growth factor (NGF) receptor activation. In the present study, we investigated the role of EGF receptor in the signaling pathway initiated by membrane depolarization of PC12 cells. Prolonged membrane depolarization induced phosphorylation of extracellular signal-regulated kinase (ERK) within 1 min in undifferentiated PC12 cells. Pretreatment of PC12 cells with the calcium chelator EGTA abolished depolarization-stimulated ERK phosphorylation, but NGF-induced phosphorylation of ERK was not affected. The chronic treatment of phorbol ester, which down-regulated the activity of protein kinase C (PKC), did not affect the phosphorylation of ERK upon depolarization. In the presence of an inhibitor of EGF receptor, neither depolarization nor calcium ionophore increased the level of ERK phosphorylation. These data imply that the EGF receptor is functionally necessary to activate ERK and neurite outgrowth in response to the prolonged depolarization in PC12 cells, and also that PKC is apparently not involved in this signaling pathway.

• Toxicological Research
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• v.11 no.2
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• pp.199-203
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• 1995

The focus of this study was to investigate that cellular parameters and glucose uptake might be altered by extracellular calcium and starvation. Addition of 1 mM $Ca^{++}$ to hepatocytes (equalling to the free calcium concentration of blood) significantly increased intracellular $Na^+$ and decreased $Na^+$ & LDH leakage. This pertains to the hepatocytes of control rats as well as those of rats fasted for 24 and 48. hr. These effects might be come from the membrane-stabilizing effects of calcium. But calcium had no effects on cell volumes, superoxide-formation and glucose uptake. Actually hepatocytes of starved rats showed changes in several cellular parameters. Starvation increased LDH leakage, glucose uptake and the total concentration of $Na^+$ and $Na^+$ whereas it markedly decreased cell volumes. Since total tonicity remained unchanged, intracellular $Na^+$ and $Na^+$ could contribute to a higher share of total osmolarity in starvation. Starvation increased the cytoplasmic pH because $R-NH^{3+}$ions and their corresponding counterions disappeared. This increase may be related to suppress the protonization of amino groups in proteins. Starvation decreased hepatic glycogen, a major compound that affects cytosolic volume of hepatocytes. The data indicate that starvation increases the glucose transport activity. The possible molecular basis will be discussed.

• Korean Journal of Microbiology
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• v.31 no.1
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• pp.79-84
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• 1993

Infection of Chinook Salmon Embryo (CHSE) cells with IPNV resulted in a significant decrease in intracellular free calcium concentration ([$Ca^{2+}$]i) compared to mock-infected cells. The degree of the decrease in [Ca$^{2+}$]i was dependent on the amount of input virus, and treatment of IPNV-infected CHSE cells with metabolic inhibitors such as cyloheximide cordycepin partially reversed the decrease in [$Ca^{2+}$]i in IPNV-infected cells. Inactiation of PINV with UV also abolished IPNV-induced decrease in [$Ca^{2+}$]i. These data suggest an active role of IPNV in the decrease of [Ca$^{2+}$]i in the infected CHSE cells. The importance of the decrease in [$Ca^{2}$i] could be supported by the finding that the production of IPNV plaques increased in the cells treated with verapamil, a calcium influex blocker, and by lowering the concentration of extracellular calcium. Decreased production of IPNV plaques was observed by elevating the extracellular calcium. Thus, it is suggested that IPNV induced a decreased in [$Ca^{2+}$]i and the decrease in [$Ca^{2+}$]i may plan an importat role in efficient replication of IPNV.ation of IPNV.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.97-99
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• 1996

Intracellular gradients of the free calcium concentration are thought to be critical for the localization of functional responses within a cell. The mechanism of mechanotransduction may be associated with the localized accumulation of calcium stores for shear stress-exposed endothelial cells. The distribution of the calcium stores and the formation of the stress fibers were investigated by the indirect double immunofluorescent staining method with the calreticulin antibody and rhodamine phalloidin under flow condition. The shear stress of steady flow reorganized the cytoskeleton structure including the bundling and translocation to focal contacts. The calcium stores translocated from the cytoplasm to the focal contacting area. Consequently. accumulation of the calcium stores may participate in the shear stress-induced cytoskeleton organization of endothelial cells.

• Journal of Yeungnam Medical Science
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• v.9 no.2
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• pp.359-381
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• 1992

This study was designed to investigate the effect of diazepam on the spontaneous contraction and oxytocin induced contraction of the isolated rat uterus. Female rat(Sprague-Dawley) pretreated with oophorectomy and 4 days administration of estrogen, weighing about 200 g, was sacrificed by cervical dislocation, and the uteruses were isolated. A longitudinal muscle strip was placed in temperature controlled($37^{\circ}C$) muscle chamber containing Locke's solution and myographied isometrically. Diazepam inhibited the spontaneous contraction and oxytocin induced contraction of the isolated rat uterus in a concentration-dependent manner. GABA, muscimol, a GABA A receptor agonist, bicuculline, a competitive GAGA A receptor antagonist, picrotoxin, a non competitive GABA A receptor antagonist, baclofen, a GABA B receptor agonist, and delta-aminovaleric acid, a GABA B receptor antagonist, did not affect on the spontaneous and oxytocin induced contraction of the isolated rat uterus. The inhibitory actions of diazepam on the spontaneous and oxytocin induced contraction were not affected by all the GABA receptor agonists and antagonists, but exceptionally potentiated by bicuculline. This potentiation-effect by bicuculline was not antagonized by muscimol. In normal calcium PSS, addition of calcium restored the spontaneous contraction preinhibited by diazepam and recovered the contractile of oxytocin preinhibited by diazepam. A23187, a calcium inophore, enhanced the restoration of both the spontaneous and oxytocin induced contraction by addition of calcium. In calcium-free PSS, diazepam suppressed the restoration of spontaneous motility by addition of calcium but allowed the recovery of spontaneous motility to a considerable extent. Diazepam could not inhibit some development of contractility by oxytocin in calcium-free PSS, but inhibited the increase in contractility by subsequent addition of calcium. These results suggest that the inhibitory action of diazepam on the rat uterine motility does not depend on or related to GABA receptors and that diazepam inhibits the extracellular calcium influx to suppress the spontaneous and oxytocin induced contractilities.

• Mycobiology
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• v.33 no.2
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• pp.121-123
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• 2005

Extracellular keratinase isolated from Aspergillus flavus K-03 was immobilized on calcium alginate. The properties and reaction activities of free and immobilized keratinase with calcium alginate were characterized. The immobilized keratinase showed proteolytic activity against soluble azo-casein and azo-keratin, and insoluble feather keratin. Heat stability and pH tolerance of keratinase were greatly enhanced by immobilization. It also displayed a higher level of heat stability and an increased tolerance toward alkaline pHs compared with free keratinase. During the durability test at $40^{\circ}C$, 48% of the original enzyme activity of the immobilized keratinase was remained after 7 days of incubation. The immobilized keratinase exhibited better stability, thus increasing its potential for use in industrial application.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.147-148
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• 2016

Generally, the vegetable oil contains glycerin esther and free fatty acid. When the vegetable oil reacts with concrete, the glycerin esther from oil induces saponification by reacting with and hydrolyzing calcium hydroxide from cement hydration. As a result of this saponification, it has been reported the expansion of concrete. although the free fatty acid from vegetable oil, as an acid, can decompose the concrete by producing soluble salt from calcium hydroxide or CSH, the hydration products of cement, there was no report on the harmful oil type for concrete. therefore, in this research, the property change of cement mortar incorporating fly ash was analyzed experimentally by immerging various types of vegetable oils.

• Journal of Mushroom
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• v.15 no.4
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• pp.216-222
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• 2017

This study was conducted to investigate the proximate composition, free sugars, amino acids, and minerals in five Lentinula edodes cultivars collected in Korea. No significant differences in the content of crude fat and crude fiber were found between the samples; however, there was significant variation in the contents of nitrogen free extract, ash, and crude protein. Three kinds of free sugars (fucose, arabinose, and glucose) were identified by HPLC, with the glucose content ranging from 5.94% to 12.08%. Sixteen kinds of free amino acids were identified: the highest content of amino acids was found in 'Sanlim5ho' (13,768.33 mg%), while the highest content of free amino acids was found in 'Sanlim4ho' (6,790.57 mg%). The minerals detected in the L. edodes cultivars were potassium, calcium, magnesium, and sodium, the contents of which ranged from 567.16-2,356.09 mg%, 3.85-7.42 mg%, 9.79-20.88 mg%, and 19.60-22.62 mg%, respectively.