• Biomaterials and Biomechanics in Bioengineering
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• v.3 no.1
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• pp.37-46
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• 2016

To maintain activity in a coenzyme/enzyme mixture system, such as ${\beta}$-nicotinamide adenine dinucleotide (NADH)/dehydrogenase, the water-soluble 2-methacryloyloxyethyl phosphorylcholine (MPC) polymers as an additive were synthesized and investigated for their stabilizing function. The inhibitor for the NADH/dehydrogenase reaction was spontaneously formed when the NADH was stored in the dehydrogenase solution. Therefore, we hypothesized that if the additive polymer could interact with an inhibitor without any adverse effect on the dehydrogenase, the activity in the NADH/dehydrogenase mixture could be maintained. We selected lactose dehydrogenase (LDH) as the enzyme, and the NADH was dissolved and incubated at $37^{\circ}C$ in the LDH solution containing the polymers. The phospholipid polymers used in this study were poly(MPC) (PMPC), poly(MPC-co-3-trimethylammonium-2-hydroxypropyl methacrylate chloride) (PMQ) and poly[MPC-co-potassium 3-methacryloyloxypropyl sulfonate ($MSO_3$)] ($PMMSO_3$). The poly($MSO_3$) was used as a reference. For the PMQ and $PMSO_3$ aqueous solutions, the activity of the NADH/LDH mixture system decreased with incubation time as the same level or lower than that in the Tris buffered solution in the absence of the polymers. However, for the poly($MPC-co-MSO_3$) ($PMMSO_3$) aqueous solution, the activity of the NADH/LDH mixed system was six times higher than that in the buffered solution even after a 3-days incubation. The LDH activity was 1.5-1.8 times higher in the presence of the $PMMSO_3$ compared with that in the $PMSO_3$ solution. The mixture of two polymers, poly(MPC) and poly($MSO_3$), did not produce any stabilization. Thus, both the MPC and $MSO_3$ units in the polymer chain had important and cooperative effects for stabilizing the NADH/LDH mixture.

• Animal cells and systems
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• v.16 no.4
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• pp.302-312
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• 2012

The purpose of this study was to examine whether Phellodendri Cortex extract (PCE) could improve learning and memory impairments caused by lipopolysaccharide (LPS)-induced inflammation in the rat brain. The effect of PCE on modulating pro-inflammatory mediators in the hippocampus and its underlying mechanism were investigated. Injection of LPS into the lateral ventricle caused acute regional inflammation and subsequent deficits in spatial learning ability in the rats. Daily administration of PCE (50, 100, and 200 mg/kg, i.p.) for 21 days markedly improved the LPS-induced learning and memory disabilities in the Morris water maze and passive avoidance test. PCE administration significantly decreased the expression of pro-inflammatory mediators such as tumor necrosis factor-${\alpha}$, interleukin-$1{\beta}$, and cyclooxygenase-2 mRNA in the hippocampus, as assessed by RT-PCR analysis and immunohistochemistry. Together, these findings suggest that PCE significantly attenuated LPS-induced spatial cognitive impairment through inhibiting the expression of pro-inflammatory mediators in the rat brain. These results suggested that PCE may be effective in preventing or slowing the development of neurological disorders, including Alzheimer's disease, by improving cognitive and memory function because of its anti-inflammation activity in the brain.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.6
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• pp.1462-1469
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• 2007

This study has been carried out to understand the effect of Gangsim-tang on the hyperglycemic mice induced with Streptozotocin(STZ). The 60 mg/kg of streptozotocin(STZ) was treated into mice twice by 24 hrs interval and then 120 mg/kg STZ was treated again 3 days after the earlier treated. Control group was administered mice with 0.9％ saline(2ml/kg), and experimental groups were administered Gangsim-tang extract(GA group, 10 ㎎/㎏/day; GB group, 30 mg/kg/day) after hyperglycemic induction daily for 6 weeks. The body weight of experimental groups was lower than control. The blood glucose concentration increased continuously, reaching to 298.9 mg/dl after 6 weeks, however, experimental groups of the GA and GB groups significantly(p<0.01) decreased in the 4, 5, and 6 weeks groups. Blood glucose tolerance test was not significant between control and experimental groups. We examined the blood transaminase activities to know the effect of herbal medicine on liver function. The glutamic-oxaloacetic transaminase(GOT) activity was lower in group GB than in control. The glutamic-pyruvic transaminse(GPT) activity was lower in group GA and GB than in control. The superoxide dismutase(SOD) and catalase activities were higher in the group GA compared to control. The results of immunohistochemical study, Langerhan's islet of pancreas was destructed by treatment of STZ in the control, and a few of insulin positive cells observed in the control and experimental group. These results suggest that administration of Gangsim-tang extract to the hyperglycemic mice induced with STZ not regeneration of ${\beta}-cells$ but control of the blood glucose level.

• Journal of Power Electronics
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• v.15 no.1
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• pp.190-201
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• 2015

This paper uses the switching function approach to present a simple state model of the Vienna-type rectifier. The approach introduces the relationship between the DC-link neutral point voltage and the AC side phase currents. A novel direct power control (DPC) strategy, which is based on the sliding mode control (SMC) for Vienna I rectifiers, is developed using the proposed power model in the stationary ${\alpha}-{\beta}$ reference frames. The SMC-based DPC methodology directly regulates instantaneous active and reactive powers without transforming to a synchronous rotating coordinate reference frame or a tracking phase angle of grid voltage. Moreover, the required rectifier control voltages are directly calculated by utilizing the non-linear SMC scheme. Theoretically, active and reactive power flows are controlled without ripple or cross coupling. Furthermore, the fixed-switching frequency is obtained by employing the simplified space vector modulation (SVM). SVM solves the complicated designing problem of the AC harmonic filter. The simplified SVM is based on the simplification of the space vector diagram of a three-level converter into that of a two-level converter. The dwelling time calculation and switching sequence selection are easily implemented like those in the conventional two-level rectifier. Replacing the current control loops with power control loops simplifies the system design and enhances the transient performance. The simulation models in MATLAB/Simulink and the digital signal processor-controlled 1.5 kW Vienna-type rectifier are used to verify the fast responses and robustness of the proposed control scheme.

• Journal of Microbiology and Biotechnology
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• v.18 no.7
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• pp.1278-1285
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• 2008

The intestinal epithelial cell (IEC) layer of the intestinal tract makes direct contact with a number of microbiota communities, including bacteria known to have deleterious health effects. IECs possess innate protective strategies against pathogenic challenge, which primarily involve the formation of a physicochemical barrier. Intestinal tract mucins are principal components of the mucus layer on epithelial surfaces, and perform a protective function against microbial damage. However, little is currently known regarding the interactions between probiotics/pathogens and epithelial cell mucins. The principal objective of this study was to determine the effects of Lactobacillus on the upregulation of MUC2 mucin and the subsequent inhibition of E. coli O157:H7 attachment to epithelial cells. In the current study, the attachment of E. coli O157:H7 to HT-29 intestinal epithelial cells was inhibited significantly by L. acidophilus A4 and its cell extracts. It is also important to note that the expression of MUC2 mucin was increased as the result of the addition of L. acidophilus A4 cell extracts (10.0 mg/ml), which also induced a significant reduction in the degree to which E. coli O157:H7 attached to epithelial cells. In addition, the mRNA levels of IL-8, IL-1$\beta$, and TNF-$\alpha$ in HT-29 cells were significantly induced by treatment with L. acidophilus A4 extracts. These results indicate that MUC2 mucin and cytokines are important regulatory factors in the immune systems of the gut, and that selected lactobacilli may be able to induce the upregulation of MUC2 mucin and specific cytokines, thereby inhibiting the attachment of E. coli O157:H7.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.3
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• pp.377-384
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• 1998

Gold compounds depress phagocytic cell responses, including chemotaxis, and respiratory burst. However, the effects of gold compounds on the function of phagocytic cells are variable according to the preparation of medicine. In this study, effect of tetrachloroauric acid on activated neutrophil responses, including respiratory burst, lysosomal enzyme release and change of intracellular $Ca^{2+}$ level and on the synthesis of interleukin-8 and granulocyte-macrophage colony stimulating factor by macrophages was studied. This study further examines how gold compounds affect the activation processes. The respiratory burst stimulated by complement C5a, degraded IgG and PMA in neutrophils was inhibited by tetrachloroauric acid. In contrast to C5a and degraded IgG, PMA-stimulated superoxide production was weakly inhibited by tetrachloroauric acid. Staurosporine, genistein, EGTA and verapamil inhibited superoxide and $H_2O_2$ production caused by C5a and degraded IgG. PMA-stimulated superoxide production was inhibited by staurosporine but was not affected by genistein. Tetrachloroauric acid, genistein, EGTA and verapamil inhibited the release of acid phosphatase and myeloperoxidase, while the effect of staurosporine was not detected. The synthesis of interleukin-8 and granulocyte-macrophage colony stimulating factor by $interleukin-1{\beta}$ in macrophages was inhibited by tetrachloroauric acid. Preincubation with tetrachloroauric acid, genistein, EGTA and verapamil, the elevation of [$Ca^{2+}_i$] evoked by C5a was inhibited. Store-regulated $Ca^{2+}$ entry in thapsigargin-pretreated neutrophils was decreased by the addition of tetrachloroauric acid and genistein. The effect of staurosporine on intracellular $Ca^{2+}$ mobilization was not observed. In conclusion, tetrachloroauric acid may suppress neutrophil responses through its inhibitory action on elevation of intracellular $Ca^{2+}$ level and protein kinase C. It might exhibit an inhibitory effect on the action of protein tyrosine kinase. Tetrachloroauric acid depresses cytokine production by macrophages.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.2
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• pp.85-94
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• 2006

A splanchic artery occlusion for 90 min followed by reperfusion of the mesenteric circulation resulted in a severe form of circulatory shock, characterized by endothelial dysfunction, severe hypotension, marked intestinal tissue injury, and a high mortality rate. The effect of defibrotide, a complex of single-stranded polydeoxyribonucleotides having antithrombotic effect, was investigated in a model of splanchnic artery occlusion (SAO) shock in urethane anesthetized rats. Occlusion of the superior mesenteric artery for 90 min produced a severe shock state, resulting in a fatal outcome within 120 min of reperfusion in many rats. Defibrotide (10 mg/kg body weight) 10 min prior to reperfusion significantly improved mean arterial blood pressure in comparison to vehicle treated rats (p＜0.05). Defibrotide treatment also significantly attenuated in the increase of plasma amino nitrogen concentration, intestinal myeloperoxidase activity, intestinal lipid peroxidation, infiltration of neutrophils in intestine and thrombin induced adherence of neutrophils to superior mesentric artery segments. Superoxide anion and hydrogen peroxide production in $1{\mu}M$ formylmethionylleucylphenylalanine (fMLP)-activated PMNs was inhibited by defibrotide in a dose-dependent fashion. Defibrotide effectively scavenged hydrogen peroxide, but not hydroxyl radical. Treatment of SAO rats with defibrotide inhibited tumor necrosis factor-${\alpha}$, and interleukin-1${\beta}$ productions in blood in comparison with untreated rats. These results suggest that defibrotide partly provides beneficial effects by preserving endothelial function, attenuating neutrophil accumulation, and antioxidant in the ischemic reperfused splanchnic circulation

• The Korean Journal of Physiology and Pharmacology
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• v.12 no.1
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• pp.25-30
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• 2008

Although many studies show that thromboxane $A_2\;(TXA_2)$ has the action of gastrointestinal (GI) motility using GI muscle cells and tissue, there are no reports on the effects of $TXA_2$ on interstitial cells of Cajal (ICC) that function as pacemaker cells in GI tract. So, we studied the modulation of pacemaker activities by $TXA_2$ in ICC with whole cell patch-clamp technique. Externally applied $TXA_2\;(5{\mu}M)$ produced membrane depolarization in current-clamp mode and increased tonic inward pacemaker currents in voltage-clamp mode. The tonic inward currents by $TXA_2$ were inhibited by intracellular application of GDP-${\beta}$-S. The pretreatment of ICC with $Ca^{2+}$ free solution and thapsigargin, a $Ca^{2+}$-ATPase inhibitor in endoplasmic reticulum, abolished the generation of pacemaker currents and suppressed the $TXA_2$-induced tonic inward currents. However, chelerythrine or calphostin C, protein kinase C inhibitors, did not block the $TXA_2$-induced effects on pacemaker currents. These results suggest that $TXA_2$ can regulate intestinal motility through the modulation of ICC pacemaker activities. This modulation of pacemaker activities by $TXA_2$ may occur by the activation of G protein and PKC independent pathway via extra and intracellular $Ca^{2+}$ modulation.

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.5
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• pp.403-412
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• 2020

Diabetic nephropathy (DN) is a hyperglycemia-induced progressive development of renal insufficiency. Excessive glucose can increase mitochondrial reactive oxygen species (ROS) and induce cell damage, causing mitochondrial dysfunction. Our previous study indicated that cilostazol (CTZ) can reduce ROS levels and decelerate DN progression in streptozotocin (STZ)-induced type 1 diabetes. This study investigated the potential mechanisms of CTZ in rats with DN and in high glucose-treated mesangial cells. Male Sprague-Dawley rats were fed 5 mg/kg/day of CTZ after developing STZ-induced diabetes mellitus. Electron microscopy revealed that CTZ reduced the thickness of the glomerular basement membrane and improved mitochondrial morphology in mesangial cells of diabetic kidney. CTZ treatment reduced excessive kidney mitochondrial DNA copy numbers induced by hyperglycemia and interacted with the intrinsic pathway for regulating cell apoptosis as an antiapoptotic mechanism. In high-glucose-treated mesangial cells, CTZ reduced ROS production, altered the apoptotic status, and down-regulated transforming growth factor beta (TGF-β) and nuclear factor kappa light chain enhancer of activated B cells (NF-κB). Base on the results of our previous and current studies, CTZ deceleration of hyperglycemia-induced DN is attributable to ROS reduction and thereby maintenance of the mitochondrial function and reduction in TGF-β and NF-κB levels.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.3760-3768
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• 2015

This study was to examine the correlation of Personality and EEG. Personality test and EEG of the 40 team leader of a business enterprise were carried out at the same time and the correlation of test results were analyzed. Personality test was done by Big 5 and brain waves were measured by 2-Channel EEG System at Fp1 and Fp2. The analysis showed a positive correlation between the Big 5 agreeableness and SRQ(Self Regulation Quotient) relaxation status which is related with alpha rhythm, and showed a negative correlation between the Big 5 openness and SRQ concentration status which is related with low_beta rhythm. It means that the personality is closely correlated with human brain cortex activation and can be checked by brainwave analysis.