• BMB Reports
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• 제45권2호
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• pp.108-113
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• 2012

Protopine is an isoquinoline alkaloid contained in plants in northeast Asia. In this study, we investigated whether protopine derived from Hypecoum erectum L could suppress lipopolysaccharide (LPS)-induced inflammatory responses in murine macrophages (Raw 264.7 cells). Protopine was found to reduce nitric oxide (NO), cyclooxygenase-2 (COX-2), and prostaglandin $E_2$ ($PGE_2$) production by LPS-stimulated Raw 264.7 cells, without a cytotoxic effect. Pre-treatment of Raw 264.7 cells with protopine reduced the production of pro-inflammatory cytokines. These inhibitory effects were caused by blocking phosphorylation of mitogen-activated protein kinases (MAP kinases) and also blocking activation of a nuclear factor kappa-light-chain-enhancer of activated B cells (NF-${\kappa}B$).

• 대한약리학회지
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• 제8권1호
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• pp.41-47
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• 1972

The author studied the adrenotropic receptors of isolated vas deferens from Ditrema temmincki Bleeker, using adrenergic activators such as epinephrine, norepinephrine, isoproterenol and phenylephrine, and adrenergic blocking agents such as phenoxybenzamine and propranolol. The results are as follows: 1. The vas deferens was stimulated by epinephrine, norepinephrine and phenylephrine, but not affected by isoproterenol. 2. The excitatory effect of phenylephrine on the vas deferens was completely blocked by phenoxybenzamine, but more stimulated by propranolol. 3. The excitatory effects of epinephrine and norepinephrine were markedly reduced by phenoxybenzamine, but stimulated by propranolol. 4. The vas deferens pretreated with phenoxybenzamine and propranolol was not affected by epinephrine and norepinephrine. 5. The vas deferens was not affected by isoproterenol and also not affected by the pretreatment with either kind of blocking agent plus isoproterenol. 6. It seemed that the vas deferens had both alpha-excitatory receptor and beta-receptor, but it was difficult to detect the character of beta-receptor whether it was inhibitory or excitatory.

• Preventive Nutrition and Food Science
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• 제20권4호
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• pp.221-229
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• 2015

Hesperidin has been shown to possess a potential inhibitory effect on vascular formation in endothelial cells. However, the fundamental mechanism for the anti-angiogenic activity of hesperidin is not fully understood. In the present study, we evaluated whether hesperidin has anti-angiogenic effects in mouse embryonic stem cell (mES)-derived endothelial-like cells, and human umbilical vascular endothelial cells (HUVECs), and evaluated their mechanism via the AKT/mammalian target of rapamycin (mTOR) signaling pathway. The endothelial cells were treated with several doses of hesperidin (12.5, 25, 50, and $100{\mu}M$) for 24 h. Cell viability and vascular formation were analyzed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and tube formation assay, respectively. Alteration of the AKT/mTOR signaling in vascular formation was analyzed by western blot. In addition, a mouse aortic ring assay was used to determine the effect of hesperidin on vascular formation. There were no differences between the viability of mES-derived endothelial-like cells and HUVECs after hesperidin treatment. However, hesperidin significantly inhibited cell migration and tube formation of HUVECs (P<0.05) and suppressed sprouting of microvessels in the mouse aortic ring assay. Moreover, hesperidin suppressed the expression of AKT and mTOR in HUVECs. Taken together, these findings suggest that hesperidin inhibits vascular formation by blocking the AKT/mTOR signaling pathways.

• 한국지역사회생활과학회지
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• 제14권3호
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• pp.13-19
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• 2003

The purpose of this study was to investigate the UVA radiation protection effects of summer hats currently on the market with the purpose of making it possible to choose a hat with suitable UVA protection. Twelve different summer hats from the market were selected for the experiment. The results are summarized as follows: It is more effective to wear a hat than not wear a hat to block UVA radiation. Summer hats with the greatest degree of protection, from highest to lowest, are cotton, straw2, and straw1. In the area of the forehead, which is rarely influenced by the irradiation angle, the cotton hat was the most effective in protecting from UVA radiation because the material density was greater than that of the straw hats. A hat with a 8.5 cm brim was more effective at blocking UVA radiation on the jaw than 6 cm, 4 cm, and 0 cm wide brims, but it still couldn't block the radiation completely. Irradiation amounts at 11:00 AM on the forehead, jaw! s and left and right cheeks were lower than amounts measured on the back of the neck. This revealed that irradiation amounts depend on the shape of the hat and time of day. A hat with a brim encircling the head was found to be more effective in blocking UVA radiation than a hat with only a front or side brim.

• 대한약리학회지
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• 제16권1호
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• pp.35-39
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• 1980

In this study, the effects of phenoxybenzamine and related drugs on the action of CCK-PZ and caerulein were examined in isolated gall bladder of guinea pig and higher esophagus strip of fowl. The strips were placed in a bath containing Locke-Ringer solution maintained at $38^{\circ}C$. Oxygen was continuously bubbled through the solution. The contractile response was measured isometrically by a force displacement transducer connected to polygraph. In isolated gall bladder preparation caerulein produced contractile response of CCK-PZ type, but the relative potency on a weight basis was 30 times stronger than CCK-PZ. The response of caerulein or CCK-PZ was not blocked by cholinergic blocking agent and both alpha and beta adrenergic blockades, however, the response of caerulein or CCK-PZ was exceptionally blocked by phenoxybenzamine. In isolated esophagus strip CCK-PZ with high concentration produced marked contraction which was not modified by atropine and other blocking agents, whereas the response was blocked by phenoxybenzamine. These results lead to the conclusion that phenoxybenzamine inherently inhibits the contractile response of CCK-PZ and caerulein on esophagus and other smooth muscle.

• The Korean Journal of Physiology and Pharmacology
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• 제5권6호
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• pp.511-519
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• 2001

Nimopidine, one of dihydropyridine derivatives, has been widely used to pharmacologically identify L-type Ca currents. In this study, it was tested if nimodipine is a selective blocker for L-type Ca currents in sensory neurons and heterologous system. In mouse dorsal root ganglion neurons (DRG), low concentrations of nimodipine $(<10\;{\mu}M),$ mainly targeting L-type Ca currents, blocked high-voltage-activated calcium channel currents by ${\sim}38%.$ Interestingly, high concentrations of nimodipine $(>10\;{\mu}M)$ further reduced the 'residual' currents in DRG neurons from ${\alpha}_{1E}$ knock-out mice, after blocking L-, N- and P/Q-type Ca currents with $10\;{\mu}M$ nimodipine, $1\;{\mu}M\;{\omega}-conotoxin$ GVIA and 200 nM ${\omega-agatoxin$ IVA, indicating inhibitory effects of nimodipine on R-type Ca currents. Nimodipine $(>10\;{\mu}M)$ also produced the inhibition of both low-voltage-activated calcium channel currents in DRG neurons and ${\alpha}_{1B}\;and\;{\alpha}_{1E}$ subunit based Ca channel currents in heterologous system. These results suggest that higher nimodipine $(>10\;{\mu}M)$ is not necessarily selective for L-type Ca currents. While care should be taken in using nimodipine for pharmacologically defining L-type Ca currents from native macroscopic Ca currents, nimodipine $(>10\;{\mu}M)$ could be a useful pharmacological tool for characterizing R-type Ca currents when combined with toxins blocking other types of Ca channels.

• Journal of Power Electronics
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• 제16권3호
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• pp.823-831
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• 2016

A high-efficiency method is proposed to suppress magnetic core imbalance in phase-shifted full-bridge (PSFB) converters. Compared with conventional solutions, such as controlling peak current mode (PCM) or adding DC blocking capacitance, the proposed method has several advantages, such as lower power loss and smaller size, because the additional current sensor or blocking capacitor is removed. A time domain model of the secondary side is built to analyze the relationship between transformer core imbalance and cathode voltage of secondary side rectifiers. An approximate control algorithm is designed to achieve asymmetric phase control, which reduces the effects of imbalance. A 60 V/15 A prototype is built to verify the proposed method. Experimental results show that the numerical difference of primary side peak currents between two adjacent cycles is suppressed from 2 A to approximately 0 A. Meanwhile, compared with the PCM solution, the efficiency of the PSFB converter is slightly improved from 93% to 93.2%.

• Journal of Periodontal and Implant Science
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• 제35권3호
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• pp.591-596
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• 2005

Amlodipine, nifedipine, and felodipine are calcium channel blocking agents, which are cause of unwanted gingival overgrowth around natural teeth. Many studies has been performed about this unwanted effects. However, the exact etiology remains uncertain.Few reports and investigations can be found in the literature on drug-induced gingival overgrowth around dental implants. The present case reports that amlodipine-induced gingival overgrowth occurred in peri-implant sites, confirms clinical and histological features in hyperplastic peri-implant tissues. Clinical and histological features of amlodipine-induced gingival overgrowth around dental implants were similar to that of tissue around natural teeth.

• Molecules and Cells
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• 제37권5호
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• pp.383-388
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• 2014

Renal cell carcinoma (RCC) is associated with a high frequency of metastasis and only few therapies substantially prolong survival. Honokiol, isolated from Magnolia spp. bark, has been shown to exhibit pleiotropic anticancer effects in many cancer types. However, whether honokiol could suppress RCC metastasis has not been fully elucidated. In the present study, we found that honokiol suppressed renal cancer cells' metastasis via dual-blocking epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC) properties. In addition, honokiol inhibited tumor growth in vivo. It was found that honokiol could upregulate miR-141, which targeted ZEB2 and modulated ZEB2 expression. Honokiol reversed EMT and suppressed CSC properties partly through the miR-141/ZEB2 axis. Our study suggested that honokiol may be a suitable therapeutic strategy for RCC treatment.

• Journal of Electrical Engineering and Technology
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• 제5권2호
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• pp.255-263
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• 2010

The compensated-current-differential relay uses the same restraining current as a conventional relay, but the differential current is modified to compensate for the effects of the exciting current. Delta winding current is necessary to obtain the modified differential current for a $Y-\Delta$ transformer. This paper describes an estimation algorithm of the delta winding current and its application to a compensated-current-differential relay for a $Y-\Delta$ transformer. Prior to saturation, the core-loss current is calculated and used to modify the differential current. When the core first enters saturation, the initial value of the core flux is obtained by inserting the modified differential current into the magnetization curve. This flux value is used to derive the magnetizing current and consequently the modified differential current. The operating performance of the proposed relay was compared against a conventional current differential relay with harmonic blocking. Test results indicate that the proposed relay remained stable during severe magnetic inrush and over-excitation, and its operating time is significantly faster than a conventional relay. The relay is unaffected by the level of remanent flux and does not require an additional restraining or blocking signal to maintain stability. This paper concludes by implementing the proposed algorithm into a prototype relay based on a digital signal processor.