• Proceedings of the KSAR Conference
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• 한국동물번식학회 2003년도 학술발표대회 발표논문초록집
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• pp.79-79
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• 2003

Embryonic stem cells are capable of differentiating into a variety of cell lineages. However, the ultimate results of differentiation in vitro greatly depend on the duration of treatment and kinds of differentiating inducers added. In order to investigate the efficiencies of various differentiation inducers and the methods of treatment, we examined differentiation patterns of human embryonic stem cell (hESC, MB03) according to several different protocols. Exp. I) Upon differentiation using retinoic acid and ascorbic acid (RA/AA), embryoid bodies (EB, for 4days) derived from hESC was exposed to Rh (10$^{-6}$ M) and AA (50 mM) for 4 days, and were allowed to differentiate in N2 medium for 7, 14, 21, or 28 days. Exp. II) When bFGF was used, neuronal precursor cells were selected for 8 days in N2 medium after EB formation. After selection, cells were expanded at the presence of bFGF (20 ng/ml) for another 6 days followed by a final differentiation in N2 medium for 7, 14, 21 or 28 days. Exp. III) In addition, to examine the effects of neurotrophic factors in the production of mature neurons, groups of cells were exposed to either BDNF (5 ng/ml) or TGF-$\alpha$(10 ng/ml) during the 28 days of final differentiation. Differentiation patterns of RA/AA or bFGF treated groups were very similar; approximately 82% and 83% of the cells, respectively, were positive for anti-NF200 antibody, while it was about 10% and 11%, respectively, for anti-NF160 antibody in 28 days in N2 medium. Alsor, cells expressing TH were as low as 5%, while the cells doubled when matured at the presence of either BDNF or TGF-$\alpha$. Cells immunoreactive to anti-GAD antibody were approximately 20%. These results suggest that a maturation step rather than differentiation induction step, which is formation of EB, effects more decisively to the ultimate differentiation pattern.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 한국통신학회 2006년도 하계종합학술발표회 논문 초록집
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• pp.676-676
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• 2006

• Korean Journal of Poultry Science
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• 제20권2호
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• pp.93-105
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• 1993

This study was carried out to determine the concentrations of previtamin D$_3$(PreD$_3$), lumisterol$_3$(L3), tachystero1$_3$(73), vitamin D$_3$(VD$_3$) and provitamin D$_3$(ProD$_3$) in leg skins of broiler chicks exposed to UVB lights (maximum intensity at 297 nm) with dose of 0.204 or 0.409 mJ/$\textrm{cm}^2$(30 or 60 min irradiation) . The broiler Hubbard line day old chicks(2 dose $\times$9 elapsed time $\times$4 replica＋10 control＝82) were fed VD-deficient diet for 31 days in a windowless subdued light room. The skin was collected at 0, 6, 12, 18, 30, 42, 66, 90 or 138 hr after UVB irradiation. The skin lipid was extracted by 9％ ethyl acetate/n-hexane, and the fraction of VD$_3$ and its analogues was purified by Sep-Pak silica cartridge. The straight phase HPLC was utilized to analyze ProD$_3$ and its products. The mole ％(absolute level expressed in ng/$\textrm{cm}^2$) of PreD$_3$ in leg skin (epidermis＋dermis) was 4.67％(44 ng/$\textrm{cm}^2$) or 3.97％(37 ng/$\textrm{cm}^2$) right after UVB irradiation by 0.204 or 0.409 mJ/$\textrm{cm}^2$(30 or 60 min) at 15 cm distance, respectively. It content in leg skin at 0 hr after exposure was 7.24％(12 ng/$\textrm{cm}^2$) or 0.92％(9 ng/$\textrm{cm}^2$), respectively. The increase in irradiation dose did not affect proportionally the If synthesis.73 concentration in leg skin was 0.58％(S ng/$\textrm{cm}^2$) or 0.57％(6 ng/$\textrm{cm}^2$), respectively 0 hr after irradiation. The VD$_3$ in leg skin of birds exposed to UVB light with dose of 0.204 or 0.409 mJ/$\textrm{cm}^2$ was 2.13％ (21 ng/$\textrm{cm}^2$) or 0.97％ (16ng/$\textrm{cm}^2$), respectively at 0 hr after exposure, 2.72％(26ng/$\textrm{cm}^2$) or 3.84％(37ng/$\textrm{cm}^2$), respectively at 6 hr, and 4.30％ ((33ng/$\textrm{cm}^2$) or 6.40％(76ng/$\textrm{cm}^2$), respectively at 12 hr. The peak concentration of VD$_3$ was presented at 18 or 30 hr when 0.204 or 0.409 mJ/$\textrm{cm}^2$) was treated, respectively. It was shown that 18~30 hr were necessary for the thermal conversion of PreD$_3$ into VD$_3$ in the leg skin of broiler chicks. The ProD$_3$ contents in leg skins of negative control, 0.204 mJ/$\textrm{cm}^2$ and 0.409 mJ/$\textrm{cm}^2$ treated birds were 966, 948 and 815 ng/$\textrm{cm}^2$, respectively at right before and after UVB exposure. It was estimated that 18 or 151 ng/$\textrm{cm}^2$ of ProD$_3$ was isomerized to PreD$_3$, L$_3$, T$_3$ and VD$_3$ when exposed to 0.204 or 0.409 mJ/$\textrm{cm}^2$, respective)y. Consequently it was shown that when double dose of UVB light was applied to irradiate the chick body, more but not double synthesis of VD$_3$ and its analogues was occured in leg skin of brolier chicks.

• Asian-Australasian Journal of Animal Sciences
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• 제24권10호
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• pp.1393-1398
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• 2011

Four 4-month old Charolais${\times}$Dorset male sheep (initial liveweight $25.0{\pm}1.1\;kg$), fitted with rumen and abomasal fistulas and nourished by total intragastric infusions, were used to study the relationships between methionine (Met) supply, nitrogen (N) retention and plasma insulin-like growth factor-I (IGF-I). Four graded levels of Met, i.e. 0 g/16 g N, 1.76 g/16 g N, 3.52 g/16 g N and 7.04 g/16 g N, were infused into abomasums as experimental treatments. The sheep and treatments were allocated in a $4{\times}3$ incomplete Latin square design (Yudon square design). The experiment lasted 3 periods and each period was 10 days. Quadratic correlations were found between Met level (x, g/16 g N) and N retention (y, g/d): y = $-0.03x^2$+0.41x+2.62, $r^2$ = 0.66, n = 12, p = 0.008, and between methionine level (x, g/16 g N) and plasma IGF-I concentration (y, ng/ml): y = $0.80x^2$-4.53x+190.24, $r^2$ = 0.51, n = 12, p = 0.009. No significant correlation was found between plasma IGF-I (x, ng/ml) and N retention (y, g/d) (p>0.05). It was concluded that Met level had a significant influence on N retention and plasma IGF-I concentration whereas IGF-I might not be an important mediator in the regulation of N metabolism by Met in growing sheep nourished by total intragastric infusions.

• Journal of Korean Society on Water Environment
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• 제29권3호
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• pp.409-419
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• 2013

In this study, the analytical method for 27 residual pharmaceuticals in raw water was developed. Online sample preconcentration/extraction and analysis with high resolution Orbitrap mass spectrometry (LC-ESI/Orbitrap MS) were performed. The calibration curves showed good linearities (above $r^2$ = 0.998) in the range of 5 ~ 1,000 ng/L. The method detection limit and the limit of quantification were 1.1 ~ 10.0 ng/L and 3.4 ~ 31.7 ng/L, respectively. Recoveries of the target compounds were between 70.1% and 115.8% (except cefadroxil, cefradine, vancomycin, and iopromide (50.2 ~ 67.0%)). The optimized analytical method can be useful to determine the residual pharmaceuticals in raw water.

• Analytical Science and Technology
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• 제36권5호
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• pp.250-257
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• 2023

The development of a spectrofluorimetric method for the determination of trimethoprim according to the reaction between O-phthalaldehyde (OPA) in highly alkaline media, and 2-mercaptoethanol (2ME) and this reaction gives fluorescent product measured at (458) nm when excited at (342) nm. The optimization of the analytical parameters that influence intensity was investigated. The intensity of fluorescence of the formed product was linearly related to the concentration of trimethoprim in the (100-1200) ng mL^-1 range. The limit of detection and limit of quantification were estimated to be (22.54) ng mL^-1 and (75.15) ng mL^-1 respectively. The utility of the proposed methods was successfully verified by analysis of trimethoprim in pure and real pharmaceutical preparations with high accuracy, the recovery percentages Re%, were found to be (100.5) % and (99.76) % for pure drug and pharmaceutical preparations respectively.

• The Korean Journal of Pain
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• 제24권3호
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• pp.146-153
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• 2011

Background: Morphine has been commonly used for postoperative pain control. We measured plasma concentrations of morphine and compared the efficacy and safety of continuous epidural analgesia (CEA) using morphinebupivacaine with intravenous patient controlled analgesia (IV-PCA) with morphine for 48 hrs after the end of the operation. Methods: Nineteen patients undergoing Mile's operation were assigned to receive a morphine loading dose of 5 mg followed by IV-PCA with 0.1% morphine (IV-PCA group, n = 9) or a morphine loading dose of 2 mg and 0.125% bupivacaine 10 ml, followed by CEA with 0.004% morphine and 0.075% bupivacaine at a rate of 5 ml/hr (CEA group, n = 10). The plasma concentrations of morphine were measured and visual analog scales (VAS) for pain were recorded at 1, 6, 12, 24, and 48 hr postoperatively and the effects on respiration and any other side effects were noted. Results: The mean maximal and minimal levels of plasma morphine were $40.2{\pm}21.2\;ng/ml$ and $23.4{\pm}9.7\;ng/ml$ for the IV-PCA group and $11.8{\pm}3.5\;ng/ml$ and $8.2{\pm}1.9\;ng/ml$ for the CEA group, respectively. Resting and dynamic pain scores were significantly lower in the CEA group than in the IV-PCA group. There were no significant differences for the effects on respiration and for any side effects between the two groups. Conclusions: We evaluated plasma concentrations of morphine with CEA using morphine-bupivacaine and IV-PCA using morphine for the postoperative pain control. The CEA group had better postoperative analgesia than that of the IV-PCA group and the incidence of side effects were not significantly different between the two groups.

• The Korea Journal of Herbology
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• 제23권4호
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• pp.171-177
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• 2008

Objectives: This study presents a reversed-phase high-performance liquid chromatography- pulsed amperometric detection(RP-HPLC-PAD) method for the determination of puerarin and daidzin in Puerariae Radix extract and Chinese medicinal preparations. Methods: Chromatographic separation was performed using a 10% acetonitrile with a reversed-phase column(Unison UK-C18, $100mm{\times}2.0mm$ I.D.; $3{\mu}m$). The analyses were detected by pulsed amperometric detector(PAD) in alkaline conditions by combining with post-column NaOH solution. Geniposide was used as an internal standard. Results: The limit of detection(S/N=3) and the limit of quantification(S/N=10) were 0.025 ng, 0.075 ng for puerarin, and 0.05 ng, 0.15 ng for daidzin, respectively. The intra- and inter-day precisions(RSDs) were less than 6.5% and average recoveries of puerarin were 99.7-101.3% and those of daidzin were 101.0-102.8%. Conclusions: According to above results, we developed a determination method for puerarin and daidzin in Puerariae Radix with high sensitivity and selectivitely.

• Journal of the Korean Society of Food Culture
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• 제32권5호
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• pp.437-445
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• 2017

This study was conducted to investigate the nutrition knowledge, dietary attitudes, dietary behaviors, smartphone usage-related dietary habits, and health-related lifestyles of higher grade students in elementary school according to risk level of smartphone overdependence. Subjects were 286 fifth and sixth grade students of elementary school in the Siheung and Ansan areas. Data were collected using self-administered questionnaires and analyzed using SPSS v. 20.0. Based on scores of S-scale (smartphone overdependence scale for adolescents), subjects who used smartphone were classified into an overdependence group (ODG, n=52) and a normal group (NG, n=234). The ODG showed a significantly longer usage time than NG on both weekdays and weekends (p<0.001). There were no significant differences in total scores of nutrition knowledge between the ODG and NG. Average total scores of dietary attitude and dietary behavior in the ODG were significantly lower than in the NG (p<0.001). There were higher risks of ODG for skipping meals (OR=8.3, 95% CI=4.027-17.099), changing eating speed (OR=4.4, 95% CI=2.209-8.822), and changing meal amount due to smartphone usage (OR=2.9 95% CI=1.233-6.623). Therefore, education programs are needed to ensure proper dietary behaviors and habits among smartphone overdependent elementary school students.

• Archives of Pharmacal Research
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• 제19권6호
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• pp.529-534
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• 1996

A high-performance liquid chromatographic (HPLC) assay has been developed for the determination of ketorolac in human serum using a new extraction method with a good recovery. Human serum samples (1.0 ml) spiked with known concentrations of ketorolac tromethamine and 10${\mu}g$ of ketoprofen as the internal standard (IS) were acidified with 200${\mu}l$ of 1 N HCl and extracted with 7 ml of n-hexane-ether (7:3 v/v). Extracts were centrifuged and organic layer was back-extracted with 400${\mu}l$ of 0.1% tromethamine solution. Twenty .mu.l of centrifuged aqueous layer was injected onto a reversed-phase octyl column and eluted with a mixture of acetonitrile, water, methanol, and triethylamine [35:55:10:0.1 (v/v), pH 3.0] at a flow rate of 1.0 ml/min. Ultraviolet detection of ketorolac and IS was carried out at 300 nm. The calibration curve obtained using peak area ratios showed a good linearity (in concentration range 10-150 ng/ml $r^2$=O.9944; in range 50-2000 ng/ml, r$^{2}$=0.9998). The mean intra-day accuracy and precision for this HPLC method were found to be 3.6 and 3.7%, respectively. The mean inter-day accuracy and precision were found to be 4.0 and 3.7%, respectively, in the concentration range 50-2000 ng/ml. The recovery of ketorolac from serum was 92.0 $({\pm}5.7)$ % at the concentration of 100 ng/ml. This method proved to be readily applicable to the assay of ketorolac in human serum.