Publications (8)12.36 Total impact
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Article: Treadmill exercise represses neuronal cell death in an aged transgenic mouse model of Alzheimer's disease.
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ABSTRACT: The present study was undertaken to further investigate the protective effect of treadmill exercise on the hippocampal proteins associated with neuronal cell death in an aged transgenic (Tg) mice with Alzheimer's disease (AD). To address this, Tg mouse model of AD, Tg-NSE/PS2m, which expresses human mutant PS2 in the brain, was chosen. Animals were subjected to treadmill exercise for 12 weeks from 24 months of age. The exercised mice were treadmill run at speed of 12 m/min, 60 min/day, 5 days/week on a 0% gradient for 3 months. Treadmill exercised mice improved cognitive function in water maze test. Treadmill exercised mice significantly reduced the expression of Aβ-42, Cox-2, and caspase-3 in the hippocampus. In parallel, treadmill exercised Tg mice decreased the phosphorylation levels of JNK, p38MAPK and tau (Ser404, Ser202, Thr231), and increased the phosphorylation levels of ERK, PI3K, Akt and GSK-3α/β. In addition, treadmill exercised Tg mice up-regulated the expressions of NGF, BDNF and phospho-CREB, and the expressions of SOD-1, SOD-2 and HSP-70. Treadmill exercised Tg mice up-regulated the expression of Bcl-2, and down-regulated the expressions of cytochrome c and Bax in the hippocampus. The number of TUNEL-positive cells in the hippocampus in mice was significantly decreased after treadmill exercise. Finally, serum TC, insulin, glucose, and corticosterone levels were significantly decreased in the Tg mice after treadmill exercise. As a consequence of such change, Aβ-dependent neuronal cell death in the hippocampus of Tg mice was markedly suppressed following treadmill exercise. These results strongly suggest that treadmill exercise provides a therapeutic potential to inhibit both Aβ-42 and neuronal death pathways. Therefore, treadmill exercise may be beneficial in prevention or treatment of AD.Neuroscience Research 10/2010; 69(2):161-73. · 2.25 Impact Factor -
Article: An effect of immediate dentin sealing on the shear bond strength of resin cement to porcelain restoration.
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ABSTRACT: The aim of this study was to determine differences in shear bond strength to human dentin using immediate dentin sealing (IDS) technique compared to delayed dentin sealing (DDS). Forty extracted human molars were divided into 4 groups with 10 teeth each. The control group was light-cured after application of dentin bonding agent (Excite® DSC) and cemented with Variolink® II resin cement. IDS/SE (immediate dentin sealing, Clearfil™ SE Bond) and IDS/SB (immediate dentin sealing, AdapterTM Single Bond 2) were light-cured after application of dentin bonding agent (Clearfil™ SE Bond and Adapter™ Sing Bond 2, respectively), whereas DDS specimens were not treated with any dentin bonding agent. Specimens were cemented with Variolink® II resin cement. Dentin bonding agent (Excite® DSC) was left unpolymerized until the application of porcelain restoration. Shear strength was measured using a universal testing machine at a speed of 5 mm/min and evaluated of fracture using an optical microscope. The mean shear bond strengths of control group and IDS/SE group were not statistically different from another at 14.86 and 11.18 MPa. Bond strength of IDS/SE group had a significantly higher mean than DDS group (3.14 MPa) (P < .05). There were no significance in the mean shear bond strength between IDS/SB (4.11 MPa) and DDS group. Evaluation of failure patterns indicates that most failures in the control group and IDS/SE groups were mixed, whereas failures in the DDS were interfacial. When preparing teeth for indirect ceramic restoration, IDS with Clearfil™ SE Bond results in improved shear bond strength compared with DDS.The journal of advanced prosthodontics 06/2010; 2(2):39-45. -
Article: A comparative study on the accuracy of the devices for measuring the implant stability.
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ABSTRACT: How the ISQ values measured by Osstell™ and Osstell™ Mentor are related, and whether the ISQ values acquired from the two machines changes in accordance with changes in implant stability are not yet fully understood. The aim of this study was to find out correlation between the ISQ values acquired from Osstell™ and Osstell™ Mentor, and to evaluate the clinical effectiveness and accuracy of two devices. Sixty two implants were inserted into 47 patients, and their ISQ values were measured using Osstell™ and Osstell™ Mentor. In the first stage surgery, the ISQ values of forty four implants inserted into thirty five patients were measured. In the second stage surgery, the values of fifty implants inserted into thirty seven patients were measured. The values were analyzed to determine the difference between the mean ISQ values of Osstell™ and Osstell™ Mentor. In addition, the correlation between implants used in the first and second stage of surgery with regard to their types and areas of insertion were analyzed. The difference between the ISQ values of 32 implants in each patient during the first and second stage was analyzed. The statistical assessment was carried out using SPSS V. 12.0 for Win. (SPSS Inc., Chicago, USA). The Pearson correlation coefficient was used to examine the correlation between Osstell™ and Osstell™ Mentor in the first and second stages of surgery, whereas the difference between their ISQ values was evaluated using a paired t-test. In the first stage, the mean ISQ value for Osstell™ and Osstell™ Mentor was 70.84 and 75.09, respectively, showing a significant difference (P < .01). In the second stage, the mean ISQ value of Osstell™ and Osstell™ Mentor was 71.76 and 75.94, respectively, also showing a significant difference (P < .01). The difference between the ISQ values in patients in the first and the second stages was significant with both instruments. The significant difference in the values obtained using the Osstell™ and Osstell™ Mentor between the first and second stages of implant surgery indicates that these values can be a convenient and precise way for evaluating the implant stability in clinical practice.The journal of advanced prosthodontics 11/2009; 1(3):124-8. -
Article: Treadmill exercise improves cognitive function and facilitates nerve growth factor signaling by activating mitogen-activated protein kinase/extracellular signal-regulated kinase1/2 in the streptozotocin-induced diabetic rat hippocampus.
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ABSTRACT: This study aimed to investigate the effects of regular treadmill exercise on nerve growth factor (NGF) expression, the improvement of cognitive function in the hippocampus of diabetic rats, and to understand the molecular mechanisms through which the relevant signaling factors act. We investigated the effects of regular treadmill exercise for 6 weeks on NGF, tyrosine kinase receptor A (TrkA), p75 receptor, phosphatidylinositol 3-kinase (PI3-K), mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase 1/2 (Erk1/2), cyclic AMP response element-binding protein (CREB), and caspase-3 protein levels; we also assessed cell survival and cognitive function. Forty male Sprague-Dawley rats were divided into four groups: (1) normal control group (NCG: n=10); (2) normal exercise group (NEG: n=10); (3) diabetes control group (DCG: n=10), and (4) diabetes exercise group (DEG: n=10). Diabetes was induced by injecting streptozotocin (STZ; 55 mg/kg dissolved in 0.05 M citrate buffer, pH 4.5, i.p.) into rats. Rats were subjected to treadmill exercise for 5 days a week over 6 weeks, and the speed of the treadmill was gradually increased. In a passive avoidance test, the retention latency in the DCG was significantly shorter than that in the DEG (P<0.05). Increased 5-bromo-2'-deoxyuridine-5'-mono-phosphate (BrdU)-labeled cells (P<0.001) and significant increases in NGF and TrkA protein levels were observed in the hippocampal dentate gyrus in the NEG and DEG (P<0.001 and P<0.01, respectively). The p75 receptor protein level significantly increased in the NEG but decreased in the DCG (P<0.001). The p-PI3-K and t-CREB protein levels significantly increased in the NEG (P<0.001 and P<0.05, respectively), whereas t-Erk1/2 significantly decreased in the DCG (P<0.01, P<0.01, respectively). p-Erk1/2 and p-CREB protein levels significantly increased in the NEG and DEG (P<0.001, P<0.001, and P<0.01, respectively). Caspase-3 protein levels significantly increased in the DCG (P<0.001). These results show that treadmill exercise improves cognitive function, increases the number of BrdU-labeled cells, and increases NGF levels, by the activation of the MAPK/Erk1/2 signaling pathway in the hippocampus of diabetic rats.Neuroscience 10/2009; 164(4):1665-73. · 3.38 Impact Factor -
Article: Exercise training acts as a therapeutic strategy for reduction of the pathogenic phenotypes for Alzheimer's disease in an NSE/APPsw-transgenic model.
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ABSTRACT: Alzheimer's disease (AD) is a progressive neurodegenerative disease for which there are few therapeutic regimens that influence the underlying pathogenic phenotypes. However, of the currently available therapies, exercise training is considered to be one of the best candidates for amelioration of the pathological phenotypes of AD. Therefore, we directly investigated exercise training to determine whether it was able to ameliorate the molecular pathogenic phenotypes in the brain using a neuron-specific enolase (NSE)/Swedish mutation of amyloid precursor protein (APPsw) transgenic (Tg) mice as a novel AD model. To accomplish this, Non-Tg and NSE/ APPsw Tg mice were subjected to exercise on a treadmill for 16 weeks, after which their brains were evaluated to determine whether any changes in the pathological phenotype-related factors had occurred. The results indicated (i) that amyloid beta-42 (Abeta-42) peptides were significantly decreased in the NSE/APPsw Tg mice following exercise training; (ii) that exercise training inhibited the apoptotic biochemical cascades, including cytochrome c, caspase-9, caspase-3 and Bax; (iii) that the glucose transporter-1 (GLUT-1) and brain-derived neurotrophic factor (BDNF) proteins induced by exercise training protected the neurons from injury by inducing the concomitant expression of genes that encode proteins such as superoxide dismutase-1 (SOD-1), catalase and Bcl-2, which suppress oxidative stress and excitotoxic injury; (iv) that heat-shock protein-70 (HSP-70) and glucose-regulated protein-78 (GRP-78) were significantly increased in the exercise (EXE) group when compared to the sedentary (SED) group, and that these proteins may benefit the brain by making it more resistant to stress-induced neuron cell damage; (v) and that exercise training contributed to the restoration of normal levels of serum total cholesterol, insulin and glucose. Taken together, these results suggest that exercise training represents a practical therapeutic strategy for human subjects suffering from AD. Moreover, this training has the potential for use in new therapeutic strategies for the treatment of other chronic disease including diabetes, cardiovascular and Parkinson's disease.International Journal of Molecular Medicine 11/2008; 22(4):529-39. · 1.98 Impact Factor -
Article: Saturated, but not n-6 polyunsaturated, fatty acids induce insulin resistance: role of intramuscular accumulation of lipid metabolites.
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ABSTRACT: Consumption of a Western diet rich in saturated fats is associated with obesity and insulin resistance. In some insulin-resistant phenotypes this is associated with accumulation of skeletal muscle fatty acids. We examined the effects of diets high in saturated fatty acids (Sat) or n-6 polyunsaturated fatty acids (PUFA) on skeletal muscle fatty acid metabolite accumulation and whole-body insulin sensitivity. Male Sprague-Dawley rats were fed a chow diet (16% calories from fat, Con) or a diet high (53%) in Sat or PUFA for 8 wk. Insulin sensitivity was assessed by fasting plasma glucose and insulin and glucose tolerance via an oral glucose tolerance test. Muscle ceramide and diacylglycerol (DAG) levels and triacylglycerol (TAG) fatty acids were also measured. Both high-fat diets increased plasma free fatty acid levels by 30%. Compared with Con, Sat-fed rats were insulin resistant, whereas PUFA-treated rats showed improved insulin sensitivity. Sat caused a 125% increase in muscle DAG and a small increase in TAG. Although PUFA also resulted in a small increase in DAG, the excess fatty acids were primarily directed toward TAG storage (105% above Con). Ceramide content was unaffected by either high-fat diet. To examine the effects of fatty acids on cellular lipid storage and glucose uptake in vitro, rat L6 myotubes were incubated for 5 h with saturated and polyunsaturated fatty acids. After treatment of L6 myotubes with palmitate (C16:0), the ceramide and DAG content were increased by two- and fivefold, respectively, concomitant with reduced insulin-stimulated glucose uptake. In contrast, treatment of these cells with linoleate (C18:2) did not alter DAG, ceramide levels, and glucose uptake compared with controls (no added fatty acids). Both 16:0 and 18:2 treatments increased myotube TAG levels (C18:2 vs. C16:0, P < 0.05). These results indicate that increasing dietary Sat induces insulin resistance with concomitant increases in muscle DAG. Diets rich in n-6 PUFA appear to prevent insulin resistance by directing fat into TAG, rather than other lipid metabolites.Journal of Applied Physiology 05/2006; 100(5):1467-74. · 3.75 Impact Factor -
Article: Pirfenidone suppressed the development of glomerulosclerosis in the FGS/Kist mouse.
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ABSTRACT: Pirfenidone (PFD) is a newly developed anti-fibrotic agent. We evaluated the effect of PFD for the prevention of renal fibrosis using a spontaneous progressive glomerulosclerosis animal model, FGS/Kist mice. Male and female FGS/Kist mice were fed a diet containing 0.5% PFD or the same control diet (CD) without PFD, for 1, 2, or 3-month periods. Body weight was monitored for the general effect of PFD on the mice. Proteinuria and glomerular filtration rate (GFR) were evaluated for renal function. The sclerosis index was examined for the morphological changes. There were no significant changes in body weight between the PFD and control groups in both sexes. Proteinuria levels were low in all the PFD groups compared to the corresponding CD groups. The sclerosis scores were also reduced in both sexes of the 3-month PFD groups (p<0.05), and glomerular filtration rates were increased in both sexes of the 3-month PFD groups compared to the CD groups. The treatment of PFD for 1 or 2-month periods did not have statistic significances but the treatment for 3 months had statistic significances in sclerosis and GFR compared to CD groups. These results suggested that long-term administration of PFD suppressed the progression of glomerulosclerosis and improved renal function of the FGS/Kist mice.Journal of Korean Medical Science 08/2003; 18(4):527-33. · 0.99 Impact Factor -
Conference Proceeding: A fuzzy relation based fault section diagnosis method for power systems using operating sequences of protective devices
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ABSTRACT: This paper proposes a novel fault section diagnosis method for power systems based on the fuzzy relation theory. Especially, the proposed method utilizes information on operating time sequences of the actuated relays and the tripped circuit breakers; therefore, the method has the capability of inferring the fault sections correctly even for the complicated multiple faults. The method proposed in this paper is intended to develop an expert system for fault section diagnosis of power systems focusing on utilizing operation sequences of protective devices. The inference is basically executed by sagittal diagrams representing the fuzzy relations. Using operating time sequences of protective devices involving the faults, the method enhances the performance of diagnosing the fault section. In the case studies for real power system, it provided less fault section candidates than without considering the time sequences. As a result, the method reduced the uncertainty and ambiguity for diagnosing the final fault sectionPower Engineering Society Summer Meeting, 2001; 02/2001
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Institutions
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2009–2010
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Dankook University
Yŏng-dong, North Chungcheong, South Korea
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