• The Journal of Korean Academy of Prosthodontics
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• v.47 no.1
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• pp.39-45
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• 2009

Statement of problem: Recently precalcification treatment has been studied to shorten the period of the implant. Purpose: This study was performed to evaluate the effect of precalcification treatment of $TiO_2$ Nanotube formed on Ti-6Al-4V Alloy. Material and methods: Specimens of $20{\times}10{\times}2\;mm$ in dimensions were polished sequentially from #220 to #1000 SiC paper, ultrasonically washed with acetone and distilled water for 5 min, and dried in an oven at $50^{\circ}C$ for 24 hours. The nanotubular layer was processed by electrochemical anodic oxidation in electrolytes containing 0.5 M $Na_2SO_4$ and 1.0 wt% NaF. Anodization was carried out using a regulated DC power supply (Kwangduck FA, Korea) at a potential of 20 V and current density of $30\;㎃/cm_2$ for 2 hours. Specimens were heat-treated at $600^{\circ}C$ for 2 hours to crystallize the amorphous $TiO_2$ nanotubes, and precalcified by soaking in $Na_2HPO_4$ solution for 24 hours and then in saturated $Ca(OH)_2$ solution for 5 hours. To evaluate the bioactivity of the precalcified $TiO_2$ nanotube layer, hydroxyapatite formation was investigated in a Hanks' balanced salts solution with pH 7.4 at $36.5^{\circ}C$ for 2 weeks. Results: Vertically oriented amorphous $TiO_2$ nanotubes of diameters 48.0 - 65.0 ㎚ were fabricated by anodizing treatment at 20 V for 2 hours in an 0.5 M $Na_2SO_4$ and 1.0 NaF solution. $TiO_2$ nanotubes were composed with strong anatase peak with presence of rutile peak after heat treatment at $600^{\circ}C$. The surface reactivity of $TiO_2$ nanotubes in SBF solution was enhanced by precalcification treatment in 0.5 M $Na_2HPO_4$ solution for 24 hours and then in saturated $Ca(OH)_2$ solution for 5 hours. The immersion in Hank's solution for 2 weeks showed that the intensity of $TiO_2$ rutile peak increased but the surface reactivity decreased by heat treatment at $600^{\circ}C$. Conclusion: This study shows that the precalcified treatment of $TiO_2$ Nanotube formed on Ti-6Al-4V Alloy enhances the surface reactivity.

• Clinical and Experimental Reproductive Medicine
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• v.31 no.3
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• pp.155-168
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• 2004

Objective: Melatonin, which is secreted by pineal gland play an important role in the regulation of ovarian function via seasonal rhythm and sleep in most mammals. It also has a role in the protection of cells by removing toxic oxygen free radicals brought about by metabolism. In the present study, effects of melatonin on the mouse oocyte maturation were examined using two different culture conditions provided with 5% or 21% oxygen concentration. Material and Method: Immature mouse oocytes were obtained from the ovarian follicles of $3{\sim}4$ weeks old ICR strain mice intraperitoneally injected with 5 I.U. PMSG 44 hour before. Under stereomicroscope, morphologically healthy oocytes with distinct germinal vesicle (GV) were liberated from the graafian follicles and collected using mouth-controlled micropipette. They were then cultured for 17 hour at $37^{circ}C$, 5% $CO_2$ and 21% $O_2$ (95% air) or 5% $CO_2$, 5% $O_2$ and 90% $N_2$. New modified Hank's balanced salt solution (New MHBS) was used as a culture medium throughout the experiments. Effects of melatonin were examined at a concentration of $0.0001{\mu}M$, $0.01{\mu}M$ or $1.0{\mu}M$. For the prevention of spontaneous maturation of immature oocytes during culture, dibutyryl cyclic AMP (dbcAMP) and/or hypoxanthine were included in the medium. Results: Under 21% oxygen condition, oocytes cultured in the presence of $0.01{\mu}M$ melatonin showed a significantly higher maturation rates, in terms of germinal vesicle breakdown (95.0% vs 89.0%) and polar body formation (88.1% vs 75.4%), compared to those cultured with $0.0001{\mu}M$ or $1.0{\mu}M$ melatonin. However, no difference was observed in oocytes cultured under 5% oxygen whether they were treated with melatonin or not. In the presence of $0.01{\mu}M$ melatonin, oocytes either cultured under 21% or 5% oxygen exhibited no difference in the polar body formation (85.6% vs 86.7%). However, in the absence of melatonin, oocytes cultured under 21% oxygen exhibited lower polar body formation (74.7%). When oocytes were cultured in the presence of dbcAMP alone or with varying concentrations of melatonin, those treated with both compounds always showed better maturation, i.e., germinal vesicle breakdown and polar body formation, compared to those cultured with dbcAMP alone. At the same concentration of melatonin, however, oocytes exposed to 21% oxygen showed poor maturation than those to 5% oxygen. Similar results were obtained from the experiments using hypoxanthine instead of dbcAMP. Conclusion: Based upon these results, it is suggested that melatonin could enhance the meiotic maturation of mouse oocytes under 21% oxygen concentration, and release oocytes from the meiotic arrest by dbcAMP or hypoxanthine regardless of the concentration of oxygen, probably via the removal of oxygen free radicals.

• The Korea Journal of Herbology
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• v.22 no.3
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• pp.117-125
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• 2007

Objective : Lonicera japonica (Caprifoliaceae) has long been used for treatment of infectious diseases in oriental countries. The aim of this study was to investigative the effect by which the aqueous extract from flower of L. japonica (LJFAE) inhibited the lipopolysaccharide (LPS)-induced inflammatory mediators in murine macrophages, RAW 264.7 cells Methods : The dried flowers of L. japonica were extracted with distilled water at $100^{\circ}C$ for 7 h. The extract was filtered through 0.45 ${\mu}m$ filter, freeze-dried. The dried extract was dissolved in Hank's balanced salt solution (HBSS) and filtered through 0.22 ${\mu}m$ filter before use. Accumulated nitrite, an oxidative product of nitric oxide (NO), was measured in the culture medium by the Griess reaction. The levels of prostaglandin E2 (PGE2), tumor necrosis factor-$\alpha$ (TNF-$\alpha$), interleukin-1$\beta$ (IL-1$\beta$), and IL-6 production, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression were measured by enzyme-linked immunosorbent assay and Western blot analysis. Results: LJFAE (10-400 ${\mu}g$/ml) per se had no cytotoxic effect in unstimulated macrophages, but LJFAE concentration-dependently reduced NO, PGE2, TNF-, IL-l, and IL-6 production and COX-2 activity caused by stimulation of LPS. The levels of iNOS and COX-2 protein expressions were markedly suppressed by the treatment with LJFAE in a concentration dependent manner. Conclusions : These results suggest that LJFAE suppress the NO and PGE2production in macrophages by inhibiting iNOS and COX-2 expression and these properties may contribute to the anti-inflammatory activity of Lonicera japonica.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.2
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• pp.192-203
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• 2007

This study histologically assessed the effect of topical alendronate application on periodontal healing in replanted teeth in fifty four SD Rats. Upper first molars in rat were extracted and replanted after dried during 15 minutes or 60 minutes in the air. In Group I, all teeth were replanted after 15 minutes of dry storage without any other treatment. In Group II and III, the pulps were removed and all teeth were replanted after soaking 10 min in Hank's balanced salt solution with/without alendronate, followed by 60 minutes of dry storage. the rats were sacrificed after 7, 15 and 30 days. The histological parameters studied were healed PDL, surface inflammatory and replacement resorption, and inflammatory severity. The following conclusions could be drawn from the present investigation. 1. Group I showed lower inflammatory root resorption and inflammation severity rate, compared to Group II and Group III. In Group I there showed effective for reattachment and regeneration of PDL. 2. In Group II, inflammatory root resorption were more severe and faster than other groups. There were extensive root resorption in the rats sacrificed after 30 days. 3 In Group III, there were localized inflammatory resorption in several areas, but extensive resorption did not occur Group III showed increase in root resorption rate, compared to Group I. However this difference was not statistically significant. 4. There were no difference between sacrificed days in replacement root resorption in all groups.