• Journal of Radiation Protection and Research
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• v.40 no.4
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• pp.194-201
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• 2015

We have investigated the EPR signal properties in 12 components of two mobile phones (LCD, OLED) using electron paramagnetic resonance (EPR) spectrometer in this study.EPR measurements were performed at normal atmospheric conditions using Bruker EXEXSYS-II E500 spectrometer with X-band bridge, and samples were irradiated by $^{137}Cs$ gamma-ray source. To identify the presence of radiation-induced signal (RIS), the EPR spectra of each sample were measured unirradiated and irradiated at 50 Gy. Then, dose-response curve and signal intensity variating by time after irradiation were measured. As a result, the signal intensity increased after irradiation in all samples except the USIM plastic and IC chip. Among the samples, cover glass(CG), lens, light guide plate(LGP) and diffusion sheet have shown fine linearity ($R^2$ > 0.99). Especially, the LGP had ideal characteristics for dosimetry because there were no signal in 0 Gy and high rate of increase in RIS. However, this sample showed weakness in fading. Signal intensity of LGP and Diffusion Sheet decreased by 50% within 72 hours after irradiation, while signals of Cover Glass and Lens were stably preserved during the short period of time. In order to apply rapidly EPR dosimetry using mobile phone components in large-scale radiation accidents, further studies on signal differences for same components of the different mobile phone, fading, pretreatment of samples and processing of background signal are needed. However, it will be possible to do dosimetry by dose-additive method or comparative method using unirradiated same product in small-scale accident.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.1
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• pp.55-59
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• 2000

A specific and sensitive sandwich enzyme-immunoassay (EIA) using Avidin-Biotin complex was developed for the measurement of GTH II levels in pituitary content and pituitary cell culture medium of the rainbow trout-(Oncorhpchus mykiss). Biotin-salmon GTH II rabbit IgG (sefondary antibody) wai purified by a protein A sepharose affinity chromatography column and that was biotinylated by using Biotin-N-hydroxysuccinimide ofter (BNHS). Non-biotin salmon GTH II rabbit IgG (first antibody) was obtained only through a protein A sepharose affinity chromatography column. The assay was performed by the so-called 'sandwich' method using a microtiter plate, A dose-response curve was obtained between $0.12 to 125 ng/ml$ of salmon GTH II. The displacement curves for pituitary extraction and pituitary cell culture medium of testosterone-treated rainbow trout were Parallel to the standard curie. The intra-assay and inter-assay coefficients of variation (CV) were $8.2{\%} (N=5) and 12.5{\%} (N=6)$, respectively, This assay system was used to measure the amount of GTH II that accumulated in the culture medium of dispersed pituitary cells in testosterone-treated immature rainbow trout, The accumulation was increased with the amount or salmon gonadotropin-releasing hormone. GTH II values determined by the present method were well correlated with those determined by radioimmunoassay. As a result, this assay system was found to be suitable for the measurement of GTH II for pituitary extraction and pituitary culture medium in many salmonid fishes.

• Korean Journal of Environmental Agriculture
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• v.18 no.1
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• pp.41-47
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• 1999

To investigate the combined effect of gamma ray irradiation and NaCl treatment on Tradescantia somatic cell pink mutations, potted plants of Tradescantia 4430 were evenly sprayed with NaCl solution(170mM) 24 hours before irradiation(NaCl+${\gamma}$) and after irradiation(${\gamma}$+NaCl). Irradiation doses were 0.3, 0.5, 1.0 and 2.0 Gy of gamma-ray. The plants irradiated only with gamma radiation were used as control group(CT). Frequency of pink mutation increased linearly with irradiation close and the peak interval of elevated mutation frequencies appeared during 6∼12 days aver irradiation in all the experimental groups. The slope of dose-response curve in CT was 5.99($r^2$=0.99), while it were 4.55($r^2$=0.98) in NaCl+${\gamma}$ and 4.33($r^2$=0.99) in ${\gamma}$+NaCl. It seemed that pre- and post-treatment of NaCl had a protective effect it against radiation-induced cell damages since it decreased the slope value by more than 24%. It is suggested that protective effect on DNA damages can be invoked in irradiated stamen hair cells by NaCl treatment.

• Journal of Pharmaceutical Investigation
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• v.39 no.1
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• pp.73-78
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• 2009

A simple LC-MS/MS method of rabeprazole in human plasma was developed and validated. Rabeprazole and Internal standard (I.S), omeprazole, were extracted from human plasma by liquid liquid extraction, chromatographic separation of rabaprazole in plasma was achieved at $45^{\circ}C$ with a Shiseido UG120 $C_{18}$ column and methanol-10 mM ammonium acetate buffer (pH 9.42 with ammonium water), as mobile phase. Rabeprazole produced a protonated precursor ion [$(M+H)^+$] at m/z 360.10 and corresponding product ion at m/z 242.21. Internal standard produced a protonated precursor ion [$(M+H)^+$] at 346.09 and corresponding product ion at m/z 198.09. This method showed linear response over the concentration range of $1{\sim}500\;ng/mL$ with correalation coefficient greater than 0.99. The lower limit of quantitation (LLOQ) using 0.2 mL plasma was 1 ng/mL, which was sensitive enough for pharmacokinetics studies. The method was specific and validated with a limit of quantitation of 1 ng/mL. The intra-day and inter-day precision and accuracy were acceptable for all samples including the LLOQ. The applicability of the method was demonstrated by analysis of plasma after administration of a single 10 mg dose to 36 healthy subject. From the plasma rabeprazole concentration versus time curves, the mean $AUC_t$ (The area under the plasma concentration-time curve from time 0 to 12 hr ) was $691.36{\pm}321.88\;ng{\cdot}hr/mL$, $C_{max}$ (maximum plasma drug concentration) of $353.21{\pm}131.52\;ng/mL$ reached $3.4{\pm}1.1\;hr$ after adiministration. The mean biological half-life of rabeprazole was $1.37{\pm}0.75\;hr$. Based on the results, this simple method could readily be used in pharmacokinetics studies.

• Journal of Pharmaceutical Investigation
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• v.35 no.5
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• pp.323-328
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• 2005

The purpose of the present study was to evaluate the bioequivalence of two torasemide tablets, Torem tablet (Roche Korea Co., Ltd., Korea, reference drug) and Boryung Torsemide tablet (Boryung Pharmaceutical Co., Ltd., Korea, test drug), according to the guidelines of Korea Food and Drug Administration (KFDA). After adding an internal standard (furosemide) to human serum, serum samples were extracted using 5 mL of ethyl acetate. Compounds were analyzed by reverse-phase HPLC method with UV detection. This method showed linear response over the concentration range of 0.05 ug/mL with correlation coefficient of 0.999. The lower limit of quantitation using 0.5 mL of serum was 0.05 ug/mL which was sensitive enough for pharmacokinetic studies. Twenty-eight healthy male Korean volunteers received each medicine at the torasemide dose of 20 mg in a $2{\times}2$ crossover study. There was a one-week washout period between the doses. Serum concentrations of torasemide were monitored by an HPLC-UV for over a period of 12 hr after the administration. $AUC_{t}$(the area under the serum concentration-time curve from time zero to 12 hr) was calculated by the linear trapezoidal rule method. $C_{max}$ (maximum serum drug concentration) and $T_{max}$ (time to reach $C_{max}$) were compiled from the serum concentration-time data. Analysis of variance was carried out using logarithmically transformed $AUC_{t}$ and $C_{max}$. No significant sequence effect was found for all of the bioavailability parameters indicating that the crossover design was properly performed. The 90% confidence intervals of the $AUC_{t}$ ratio and the $C_{max}$ ratio for Boryung Torsemide/Torem were log 0.97-10g 1.03 and log 0.93log 1.12, respectively. These values were within the acceptable bioequivalence intervals of log 0.80-log 1.25. Thus, the criteria of the KFDA guidelines for the bioequivalence was satisfied, indicating Boryung Torsemide tablet and Torem tablet are bioequivalent.

• Journal of Dairy Science and Biotechnology
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• v.28 no.2
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• pp.13-18
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• 2010

Electron Spin Resonance (ESR) spectroscopy has been used to detect the presence of radiation-induced free radicals in biological samples since the mid 1950s and to irradiate foods containing cellulose, crystalline sugar, and bone. Therefore, we analyzed the ESR spectrum of irradiated infant formula and its ingredients in this study. Samples were irradiated with 2 different radiation sources of $^{60}Co$ gamma rays and electron beams (EBs), and the absorbed doses were 0, 1, 3, 5, and 7 kGy. ESR measurements were performed under normal atmospheric conditions using a JEOL JES-FA100 spectrometer equipped with an X-band bridge. Irradiated infant formula showed anunsymmetrical spectrum ($g_1$=2.0050, $g_2$=2.0006); in contrast, non-irradiated samples showed asymmetrical spectrum. The ingredients of irradiated samples showed a multi-component ESR signal in glucose and lactose and a singlet-type spectrum in milk powder (g=2.0050). $R^2$ of the dose-response curve showed a fine linearity of over 0.95 across the entire sample. We also compared the spectra of identical samples irradiated with $^{60}Co$ gamma rays and EBs, because EBs can be used for food irradiation in foreign countries, although this is not permitted in Korea. However, we could not find any significant differences according to the types of radiation source. Thus, ESR spectroscopy can be used to detect irradiated infant formula and several types of primary ingredients in this formula.

• Journal of Pharmaceutical Investigation
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• v.37 no.5
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• pp.315-321
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• 2007

The purpose of the present study was to evaluate the bioequivalence of two lercanidipine hydrochloride tablets, Zanidip tablet (LG Life Sciences Ltd., Korea, reference drug) and Samchundang Lercanidipine tablet 10 mg (Sam Chun Dang Pharm. Co. Ltd., Korea, test drug), according to the guidelines of Korea Food and Drug Administration (KFDA). After adding an internal standard (amlodipine maleate) to human serum, serum samples were extracted using hexan-isoamyl alcohol (100:1, v/v). Compounds were analyzed by liquid chromatography/tandem mass spectrometry. This method showed linear response over the concentration range of 0.05-20 ng/mL with correlation coefficient of 0.9999. The lower limit of quantitation using 0.5 mL of serum was 0.05 ng/mL which was sensitive enough for pharmacokinetic studies. Thirty healthy male Korean volunteers received each medicine at the lercanidipine hydrochloride dose of 20 mg in a $2\;{\times}\;2$ crossover study. There was a one-week washout period between the doses. Serum concentrations of lercanidipine were monitored by an LC/MS/MS fer over a period of 24 hr after the administration. $AUC_t$ (the area under the serum concentration-time curve from time 0 to 24 hr) was calculated by the linear trapezoidal rule method. $C_{max}$ (the maximum serum drug concentration) and $T_{max}$ (the time to reach $C_{max}$) were compiled from the serum concentration-time data. Analysis of variance was carried out using logarithmically transformed $AUC_t$ and $C_{max}$. No significant sequence effect was found for all of the bioavailability parameters, indicating that the crossover design was properly performed. The 90% confidence intervals of the $AUC_t$ ratio and the $C_{max}$ ratio for Samchundang Lercanidipine/Zanidip were log 0.9505-log 1.2258 and log 0.9987-log 1.2013, respectively. These values were within the acceptable bioequivalence intervals of log 0.80-log 1.25. Thus, the criteria of the KFDA guidelines for the bioequivalence was satisfied, indicating Samchundang Lercanidipine tablet 10 mg and Zanidip tablet are bioequivalent.

• Journal of Pharmaceutical Investigation
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• v.40 no.2
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• pp.109-115
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• 2010

The purpose of the present study was to evaluate the bioequivalence of two choline alphoscerate soft capsules, Gliatilin soft capsule (Daewoong Pharmaceuticals Co., Ltd.) and Cholicerin soft capsule (Sam Chun Dang Pharm. Co., Ltd.), according to the guidelines of Korea Food and Drug Administration (KFDA). Serum concentrations of choline after oral administration of choline alphoscerate were determined using a validated LC/MS/MS method. This method showed linear response over the concentration range of 0.5-20 ${\mu}g$/mL with correlation coefficient of 0.9999. The lower limit of quantitation using 100 ${\mu}L$ of serum was 0.5 ${\mu}g$/mL which was sensitive enough for pharmacokinetic studies. Thirty six healthy male Korean volunteers received each medicine at the choline alphoscerate dose of 1200 mg in a $2{\times}2$ crossover study. There was a one-week washout period between the doses. Blood samples were taken at predetermined time intervals up to 8 hr. $AUC_t$ (the area under the serum concentration-time curve from time 0 to 8 hr) was calculated by the linear trapezoidal rule method. $C_{max}$ (the maximum serum drug concentration) and $T_{max}$ (the time to reach $C_{max}$) were compiled from the serum concentration-time data. Analysis of variance was carried out using logarithmically transformed $AUC_t$ and $C_{max}$. No significant sequence effect was found for all of the bioavailability parameters, indicating that the crossover design was properly performed. The 90% confidence intervals of the $AUC_t$ ratio and the $C_{max}$ ratio for Cholicerin/Gliatilin were log0.9998-log1.1172 and log0.9938-1.0944, respectively. These values were within the acceptable bioequivalence intervals of log0.80-log1.25. Thus, the criteria of the KFDA guidelines for the bioequivalence was satisfied, indicating Cholicerin soft capsule and Gliatilin soft capsule are bioequivalent.

• Korean Journal of Environmental Biology
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• v.17 no.3
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• pp.331-335
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• 1999

The present study was carried out to investigate the combined effect of radiation and photoperiod (PP) regimes on Tradescantia 4430 somatic cell mutations. Potted plants were irradiated with 0.3, 0.5 and 1.0 Gy of gamma radiation from 60Co source. The plants irradiated only with gamma radiation were used as control group (CT). The somatic cell mutation rate in 0.5 Gy irradiated CT and PP20 group started to increase on the 6th day and reached a maximum value on the l0th day and 9th day after irradiation while the rate in the experimental group under 4 hours of photoperiod a day (PP4) started to increase on the l0th day and reached a maximal value on the 16th day post-irradiation. The slope of dose-response curve in CT was 5.99 ($r^2$=0.99), while it was 6.93 ($r^2$=0.98) in PP20 and 11.74 ($r^2$=0.99) in PP4, respectively. The biological efficacy of radiation in the induction of pink mutation increased by 15.7% in PP20 and 95.9 % in PP4, respectively. It is suggested that photoperiod regimes unfavorable to the plant have an additive effect on radiation-induced mutations and a delaying or inhibiting effect on cell damage repair, as well.

• Journal of dental hygiene science
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• v.16 no.5
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• pp.339-348
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• 2016

We investigated the gender-specific association between average volume of alcohol consumption, binge drinking, and periodontitis using representative nationwide data. In total, we included 3,549 men and 4,810 women, aged 19 years and older, who participated in the sixth Korea National Health and Nutrition Examination Survey performed in 2013~2014. According to the average volume of alcohol consumption, study participants were grouped as follows: mild drinkers (0.1~2.0 drinks/day in men and 0.1~1.0 drink/day in women), moderate drinkers (2.1~4.0 drinks/day in men and 1.1~2.0 drinks/day in women), and heavy drinkers (>4.0 drinks/day in men and >2.0 drinks/day in women). Additionally, binge drinking was categorized as never (no binge drinking), rarely (<1 time/month), occasionally (1 time/month), frequently (1 time/week), and always (almost every day/week). Periodontitis was defined as a community periodontal index equal to code 3 or greater. In men, after controlling for covariates, the association between average volume of alcohol consumption and periodontitis showed a J-shaped curve; the risk of periodontitis was significantly higher in moderate drinkers (odds ratio [OR], 1.25; 95% confidence interval [CI], 1.01~1.56) and heavy drinkers (OR, 1.39; 95% CI, 1.04~1.87) than in mild drinkers. In contrast, no significant association between average volume of alcohol consumption and periodontitis was observed in women. In a fully adjusted analysis, which used 'never binge drinking' as a reference, a significant dose-response relationship between binge drinking and periodontitis was observed only in men: rarely (OR, 1.64; 95% CI, 1.16~2.34), occasionally (OR, 1.51; 95% CI, 1.05~2.16), frequently (OR, 1.58; 95% CI, 1.07~2.33), and always (OR, 2.56; 95% CI, 1.56~4.22) (p for trend=0.005). In conclusion, unhealthy drinking patterns such as moderate or heavy alcohol consumption and binge drinking were significantly associated with periodontitis in men but not in women.