• Animal Bioscience
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• v.36 no.9
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• pp.1367-1375
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• 2023

Objective: Pigment production and distribution are controlled through multiple proteins, resulting in different coat color phenotypes of sheep. Methods: The expression distribution of vimentin (VIM) and transthyretin (TTR) in white and black sheep skins was detected by liquid chromatography-electrospray ionization tandem MS (LC-ESI-MS/MS), gene ontology (GO) statistics, immunohistochemistry, Western blot, and quantitative real time polymerase chain reaction (qRT-PCR) to evaluate their role in the coat color formation of sheep. Results: LC-ESI-MS/MS results showed VIM and TTR proteins in white and black skin tissues of sheep. Meanwhile, GO functional annotation analysis suggested that VIM and TTR proteins were mainly concentrated in cellular components and biological process, respectively. Further research confirmed that VIM and TTR proteins were expressed at significantly higher levels in black sheep skins than in white sheep skins by Western blot, respectively. Immunohistochemistry notably detected VIM and TTR in hair follicle, dermal papilla, and outer root sheath of white and black sheep skins. qRT-PCR results also revealed that the expression of VIM and TTR mRNAs was higher in black sheep skins than in white sheep skins. Conclusion: The expression of VIM and TTR were higher in black sheep skins than in white sheep skins and the transcription and translation were unanimous in this study. VIM and TTR proteins were expressed in hair follicles of white and black sheep skins. These results suggested that VIM and TTR were involved in the coat color formation of sheep.

• Analytical Science and Technology
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• v.28 no.2
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• pp.86-97
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• 2015

Recently, the consumption of dietary supplements has increased because of people’s greater interest in health. Unfortunately, the sales of dietary supplements containing unauthorized substances such as drugs have also increased. We developed a rapid, accurate method for the simultaneous determination of antihistamines using liquid chromatography tandem mass spectrometry with a multiple reaction monitoring mode. The limit of detection (LOD) and limit of quantification (LOQ) of the instrument used in this method were in the ranges 0.0003-0.3 and 0.0009-0.6 µg mL⁻¹, respectively. The linearity of the method was > 0.99. The precision levels of the method were 0.1-9.8% (intra-day) and 0.3-9.6% (inter-day), and the levels of accuracy of the method were 82.7-115.0% (intra-day) and 84.3-113.0% (inter-day). The mean of recovery of the method was in the range of 83.9-117.9% and the RSD of the stability was less than 5.9%.

• Analytical Science and Technology
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• v.25 no.1
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• pp.19-24
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• 2012

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the quantitative determination of ertapenem in human plasma and urine. After addition of internal standard (ceftazidime), plasma and urine was diluted with methanol and analyzed by LC-MS/MS. Using MS/MS with multiple reaction monitoring (MRM) mode, ertapenem were selectively detected without severeinterference from human plasma and urine. The standard calibration curve for ertapenem was linear ($r^2$= 0.9996)over the concentration range 1~100 ${\mu}g/mL$ in human plasma. The intra- and inter-day precision over the concentration range of ertapenem was lower than 8.9% (correlation of variance, CV), and accuracy was between 97.2~106.2%. On the other hand, it was showed good relationship ($r^2$= 0.9992) and the precision (intra- and inter-day) over the concentration range of ertapenem was lower than CV 7.2%, and accuracy was between 97.9~111.6% for urine. This method has been successfully applied to the pharmacokinetic study of ertapenem in human plasma and urine.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.12
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• pp.1753-1757
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• 2012

A new liquid chromatographic tandem mass spectrometric (LC-MS/MS) assay for the quantification of ginsenoside Rb1 in human plasma was developed and validated. The separation was performed on a Agilent C18 column ($4.6mm{\times}150mm$, particle size 5 ${\mu}m$) with a gradient elution of 0.1% formic acid in water and 0.1% formic acid in methanol and a flow rate of 0.9 mL/min. The analyte was determined using electrospray positive ionization mass spectrometry in the multiple reaction monitoring (MRM) mode (m/z 1131.714${\rightarrow}$365.303). Human plasma samples were extracted with acetone : water (50:50) by the liquid-liquid extraction method. The method was linear over the dynamic range of 10~500 ng/mL with a correlation coefficient of r=0.9995. The intra-and inter-day precision over the concentration range of ginsenoside Rb1 was lower than 5.8% (correlation of variance, CV), and the accuracy was between 96.0~104.6%. This LC-MS/MS assay of ginsenoside Rb1 in human plasma is applicable for quantification in a pharmacokinetic study.

• Analytical Science and Technology
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• v.21 no.1
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• pp.34-40
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• 2008

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the quantitative determination of lercanidipine in human plasma. After addition of internal standard (amlodipine), plasma was precipitated with acetonitrile and the supernatant was evaporated. The residues were dissolved in 50 % acetonitrile and analyzed by LC-MS/MS. Using MS/MS with multiple reaction monitoring(MRM) mode, lercanindipine were selectively detected without severe interference from human plasma. The standard calibration curve for lercanidipine was linear (r = 0.9994) over the concentration range 0.05-20.0 ng/mL in human plasma. The intra- and inter-day precision over the concentration range of lercanidipine was lower than 11.7 % (correlation of variance, CV), and accuracy was between 94.4-114.8 %. This method has been successfully applied to the pharmacokinetic study of lercanidipine in human plasma.

• Analytical Science and Technology
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• v.21 no.6
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• pp.535-542
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• 2008

A liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI/MS/MS) method was developed for the determination and confirmation of clenbuterol in bovine muscle and milk. Clenbuterol and clenbuterol-D9 using as an internal standard in samples were extracted with ethyl acetate after hydrolysis and evaporated to dryness. The extracts were dissolved in 20% methanol and cleaned using HLB solid-phase extraction cartridge. The analytes were detected by LC-ESI/MS/MS on a $C_{18}$ column. Mass spectral acquisition was done in selected reaction monitoring (SRM) in positive ion mode to provide a high degree of sensitivity. Using MS/MS with SRM mode, the transitions (precursor to product) monitored were m/z 277${\rightarrow}$203 for clenbuterol, and m/z 286${\rightarrow}$204 for internal standard. The limits of quantitation (LOQ) and mean recoveries of clenbuterol in bovine muscle were $0.2{\mu}g/kg$ and 84.3~91.1%, respectively. The LOQ and mean recoveries in milk were $0.05{\mu}g/kg$ and 87.7~98.3%, respectively.

• Analytical Science and Technology
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• v.20 no.4
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• pp.331-338
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• 2007

Licorice, Glycyrrhizae Radix is widely used as a herbal medicines and a dietary supplements in East Asia. We employed high performance liquid chromatography electrospray ionization tandem mass spectrometry to determine liquiritin and glycyrrhizin in the Glycyrrhizae Radix. Liquiritin and glycyrrhizin in Glycyrrhizae Radix were ionized by positive ion pneumatically assisted electrospray and detected by HPLC-MS/MS in the multiple-reaction monitoring (MRM) mode using precursor ${\rightarrow}$ product ion combinations at m/z $436.2{\rightarrow}257.0$ and $823.4{\rightarrow}453.4$, respectively. The assay had a calibration range from 10 to 3,000 ng/mL. The limits of detection (LOD) of the liquiritin and glycyrrhizin were 0.4 ng/mL and 0.01 ng/mL, respectively. The reproducibility and repeatability (relative standard deviation) at different analyte concentrations varied from 103 to 113 % and 0.95 to 1.8 %, respectively. According to the above results, HPLC-MS/MS method permits assignment of tentative structures such as liquiritin and glycyrrhizin in the Glycyrrhizae Radix.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.8
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• pp.1197-1206
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• 2016

Adipose tissue in the loin muscle area of beef cattle as a marbling factor is directly associated with beef quality. To elucidate whether properties of proteins involved in depot specific adipose tissue were sex-dependent, we analyzed protein expression of intramuscular adipose tissue (IMAT) and omental adipose tissue (OMAT) from Hanwoo cows, steers, and bulls of Korean native beef cattle by liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based proteomic analysis, quantitative polymerase chain reaction (PCR) and western blot analysis. Two different adipose depots (i.e. intramuscular and omental) were collected from cows (n = 7), steers (n = 7), or bulls (n = 7). LC-MS/MS revealed a total of 55 and 35 proteins in IMAT and OMAT, respectively. Of the 55 proteins identified, 44, 40, and 42 proteins were confirmed to be differentially expressed in IMAT of cows, steers, and bulls, respectively. In OMAT of cows, steers, and bulls, 33, 33, and 22 were confirmed to be differentially expressed, respectively. Tropomyosin (TPM) 1, TPM 2, and TPM3 were subjected to verification by quantitative PCR and western blot analysis in IMAT and OMAT of Hanwoo cows, steers, and bulls as key factors closely associated with muscle development. Both mRNA levels and protein levels of TPM1, TPM2, and TPM3 in IMAT were lower in bulls compared to in cows or steers suggesting that they were positively correlated with marbling score and quality grade. Our results may aid the regulation of marbling development and improvement of meat quality grades in beef cattle.

• Journal of Food Hygiene and Safety
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• v.29 no.2
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• pp.123-130
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• 2014

A simultaneous determination was developed for 9 aminoglycoside antibiotics (amikacin, apramycin, dihydrostreptomycin, gentamicin, hygromycin B, kanamycin, neomycin, spectinomycin, and streptomycin) in meat by liquid chromatography tandem mass spectrometry (LC-MS/MS). Each parameter was established by multiple reaction monitoring in positive ion mode. The developed method was validated for specificity, linearity, accuracy, and precision based on CODEX validation guideline. Linearity was over 0.98 with calibration curves of the mixed standards. Recovery of 9 aminoglycosides ranged on 60.5~114% for beef, 60.1~112% for pork and 63.8~131% for chicken. The limit of detection (LOD) and limit of quantification (LOQ) were 0.001~0.009 mg/kg and 0.006~0.03 mg/kg, respectively in livestock products including beef, pork and chicken. This study also performed survey of residual aminoglycoside antibiotics for 193 samples of beef, pork and chicken collected from 9 cities in Korea. Aminoglycosides were not found in any of the samples.

• Journal of Pharmaceutical Investigation
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• v.38 no.4
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• pp.261-267
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• 2008

The aim of the present study was to evaluate the bioequivalence of two gabapentin preparations. We used Neurontin tablet 800 mg (Pfizer Korea Inc.) as a reference drug for bioequivalence of Gabalep tablet 800 mg (Chong Kun Dang Pharmaceutical Co., Korea), and performed this whole study according to the guidelines of Korea Food and Drug Administration (KFDA). Twenty five healthy male volunteers were administered with each drug in a randomized $2{\times}2$ cross-over study with one week washout interval. After drug administration, blood was taken at predetermined time intervals ($0{\sim}24$ hours) and the concentrations of gabapentin in serum were determined using an high performance liquid chromatography-tandem mass spectrometer (LC-MS/MS) employing electrospray ionization technique and operating in multiple reaction mornitoring (MRM). The analytical method was validated in specificity, accuracy, precision and linearity. The phar-macokinetic parameters such as AUCt and Cmax were calculated and ANOVA test was utilized for the statistical analysis of the parameters using logarithmically transformed AUCt and Cmax. $Mean{\pm}SD$. of AUCt and Cmax value for reference drug and test drug were $29.94{\pm}9.23\;({\mu}g/mL{\cdot}hr)$ and $3.12{\pm}1.11\;({\mu}g/mL{\cdot}hr)$, and $31.48{\pm}9.77\;({\mu}g/mL{\cdot}hr)$ and $3.15{\pm}1.03\;({\mu}g/mL)$, respectively. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log(0.8) to log(1.25) for AUCt and Cmax, respectively. These results indicate that Gabalep tablet 800 mg is bioequivalent to Neurontin tablet 800 mg.