• Journal of Pharmaceutical Investigation
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• v.35 no.2
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• pp.123-127
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• 2005

An HPLC method was employed for the determination of ethambutol in human plasma. After addition of internal standard (IS, octylamine, $2\;{\mu}g/mL$) and alkalinization of the plasma with 5 M sodium hydroxide, the drug and IS were extracted into the mixture of chloroform and diethyl ether (40:60, v/v). Following a 15-min vortex-mixing and a 10min centrifugation, the organic phase was spiked with $100{\mu}L$ of phenylethylisocyanate $(2000{\mu}g/mL)$ for chemical derivatization, mixed for 5 min and evaporated to dryness under a stream of nitrogen. The residue was reconstituted with $100{\mu}L$ of mobile phase and $20{\mu}L$ was injected into C18 column with a mobile phase consisting of methanol:water (70:30, v/v). The samples were detected utilizing an ultraviolet detector at 200 nm. The method was specific and validated with a limit of $0.15\;{\mu}g/mL$. Intra- and inter-day precision and accuracy were acceptable for all quality control samples including the lower limit of quantification. The applicability of this method was demonstrated by analysis of human plasma after oral administration of a single 1200-mg dose to 20 healthy subjects. From the plasma ethambutol concentration vs. time curves, the mean AUC was $9.61{\pm}1.64\;{\mu}g{\cdot}hr/mL$ and Cmax of $2.68\;{\mu}g/mL$ reached 2.73 hr after administration. The mean biological half-life of ethambutol was $3.46{\pm}1.21$ hr. Based on the results, this simple and validated assay could readily be used in any pharmacokinetic studies using humans.

• Journal of Food Hygiene and Safety
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• v.28 no.2
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• pp.158-167
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• 2013

This study was carried out to assess the safety of cereals and their products (20 species, 205 samples) distributed in Gyeonggi province by analyzing contamination levels such as exposure frequency of Aflatoxins and Deoxynivalenol (DON). Aflatoxins were detected in 16 (8%) samples in total with a range of 0.01~27.88 ${\mu}g/kg$, including 3 of 9 bake flour (33%), 2 of 6 dried corn (33%), 3 of 12 frying flour (25%) and 2 of 11 sorghum (18%). DON was found in 56 (27%) samples including 11 of 13 adlay (85%), 6 of 8 wheat (75%), 6 of 10 processed corn for popcorn (60%), 6 of 11 sorghum (55%) and 7 of 16 barley (44%) with a range of 2.2~754.4 ${\mu}g/kg$. In particular, both Aflatoxins and DON were detected in 8 samples (2 millet, 2 wheat, 1 sorghum, 1 adlay, 1 dried corn, 1 bake flour) simultaneously. As a result of this study, we found that an adult is exposed to Aflatoxins of $0.80({\times})10^{-3}{\mu}g/kg$ b.w./day and DON of 0.18 ${\mu}g/kg$ b.w./day. The quantity of exposure to DON amounted to 18.5 percentage level compared with PMTDI 1 ${\mu}g/kg$ b.w./day suggested on JECFA, therefore we can assess that the possibility of health risks by intake cereals distributed in Gyeonggi province is low. However the concentration of Aflatoxins in one dried corn was 27.88 ${\mu}g/kg$ which was over the maximum residue limits (MRL) suggested on internal and external level, the monitoring about mycotoxin should be conducted on continuously.

• Korean Journal of Veterinary Service
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• v.24 no.1
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• pp.31-41
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• 2001

This study was carried out to identify causative agents from california mastitis test(CMT) positive mastitic milk, and to examine the antimicrobial susceptibility of 50 heads in Seongju and Chilgok area of Gyeongbuk province. Sulfadimethoxine sodium(SMS) was intramuscularly administered once to four mastitis Infected dairy cattle at the rate of 10mg/kg body weight. After injection of SMS, the depletion rate of serum and milk from the cattle were periodically measured for five days. The CMT positive number from 50 heads showed 46% and that of 200 quarters was 47(23.5%). From 39 quarters of 47 heads 39 different microorganisms were identified. These organisms were classified into 12 species : Staphylococcus aureus 8(20.5%), Sta hemolyticus 6(15.4%), Streptococcus bovis 4(10.3%), Sta hyicus 3(7.7%), Sta epidemidis. Sta xylosus, Sta sciuri 2(5.1%), Str agalactiae 2(5.1%), Escherichia coli(10.3%), three Enterobacter cloacae(7.7%), two Ent aerogenes(5.1%) and one Salmonella spp(2.6%). As the results of antibiotic susceptibility test, gentamicin(Gm, 11 species 27 strains, 69.5%), cephalotin(Cf, 9 species 24 strains, 61.5%), sulfamethoxazole(Stx, 8 species 14 strains, 43.6%), tetracycline(Tc, 8 species 14 strains, 35.9%), and streptomycin(Sm), lincomycin(Lm), cefoperazon(Cp) and penicillin(Pc) have a highly resistance(7.7% ～5.1%). However, carbenicillin (Cb), amikacin(Ah) have no susceptible for all drugs. The mean residual concentration of SMS in serum according to the time lapsed were showed 33.964 $\pm$ 4.435ppm at the 4 hours after intramuscularly injection(AII). It was significantly(p<.05) decreased to 6.596 $\pm$ 3.402, 0.217 $\pm$ 0.119 and 0.005 $\pm$ 0.004ppm at the 1st, 3rd and 5th day AII. The mean concentration of SMS in milk was significantly(p<.05) decreased from 0.920 $\pm$ 0.42ppm to 0.084 $\pm$ 0.016ppm between 8 hours and 1 day AII. As the results of this experiments, sulfadimethoxine was residued at the level of no less than 0.01ppm in milk on the 2nd day AII. Thus, this results would be able to be used the basic index for prevention of sulfonamides residue in milk after treatment of dairy mastitis.

• Journal of Applied Biological Chemistry
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• v.56 no.1
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• pp.29-35
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• 2013

This study was performed to analyze 48 kinds of pesticide residues using gas chromatography (GC)/nitrogen phosphorous detector, GC/micro electron capture detector, GC/mass selective detector, and high performance liquid chromatograph/diode array detector in 186 fresh ginseng samples collected in the Seoul area from 2010 to 2011. Fresh ginseng dietary intakes were estimated using the data from the 2009 Korea National Health and Nutrition examination survey. Residual pesticides were detected in 79 samples (42.5%) with eight different fungicides. Only 20 samples (10.8%) exceeded the maximum residue limits (MRLs) for pesticides registered by the Korea Food & Drug Administration. Among them, tolclofos-methyl residues (10.2%) exceeded the MRL for fresh ginseng in 18 ginseng seedlings and one of the two-year old fresh ginseng plants, and the residual level in just one ginseng seedling violated the MRL for pyrimethanil. The results showed that residual pesticides levels in marketable fresh ginseng around Seoul were relatively safe. The percent acceptable daily intake (%ADI) was calculated using pesticide residues in fresh ginseng and dietary intakes of fresh ginseng. The risk caused by pesticide residues in fresh ginseng was very low.

• Microbiology and Biotechnology Letters
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• v.42 no.3
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• pp.258-266
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• 2014

Sweet potato soju (SPS), a form of traditional distilled alcoholic liquor in Korea, is manufactured by the distillation of fermented broth under normal pressure, thus providing it for a uniquely smooth taste infused with the flavor of sweet potato. After distillation, the lees of SPS is produced as by-product and discarded. In this study, the ethanol and hot water extracts of lees of SPS, and their subsequent organic solvent fractions using hexane, ethylacetate (EA), butanol, and water residue were prepared in an effort at the efficient re-use of the lees of SPS. The ethanol extraction yield was 1.36-fold higher than that of the hot water extraction, and the EA fraction revealed the highest total polyphenol content among the solvent fractions. The various extracts and solvent fractions did not demonstrate hemolytic activity at up to 0.5 mg/ml concentrations against human red blood cells. In the bioactivity assay, only the EA fraction displayed a broad spectrum of anti-microbial activity against different pathogenic and food spoilage bacteria, and demonstrated significant anti-coagulation activity by inhibitions of thrombin, prothrombin and blood coagulation factors. Furthermore, only the EA fraction from the hot water extract of the lees of SPS showed anti-platelet aggregation activity, which is comparable to aspirin (a commercially available drug). Our results suggest that the EA fraction of the hot water extract prepared from the lees of SPS has a high potential as a novel resource for anti-microbial and anti-thrombosis agents.

• The Korean Journal of Pesticide Science
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• v.15 no.1
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• pp.15-21
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• 2011

Monitoring or follow-up surveying pesticide residues in agricultural commodities is the key to meet the international regulations and to enhance international competitiveness of Korean agricultural commodities. Six neonicotinoid insecticides, acctamiprid, clothianidin, dinotefuran, imidacloprid, thiacloprid, and thiamethoxam were monitored in 95 paprika samples collected from Gyeongnam area. Thc pesticide residues were extracted by EN 15662 buffer based on the QuEChERS method, clean-upped with dispersive solid-phase extraction method to remove interfering pigments, and analyzed using UPLC-MS/MS. The neonicotinoid pesticides were detected in 90.5% of the paprika samples. Two or more pesticides were detected in 82.3% of samples. Although detection frequencies were high, all samples complied with the maximum residue limits (MRLs) set by both the Korea Food and Drug Administration (KFDA) and Japanese Ministry of Health, Labour and Welfare.

• Journal of the Korean Magnetic Resonance Society
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• v.12 no.1
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• pp.1-13
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• 2008

Acetyl-CoA carboxylase (ACC) catalyzes the first step in fatty acid biosynthesis: the synthesis of malonyl-CoA from acetyl-CoA. As essential regulators of fatty acid biosynthesis and metabolism, ACCs are regarded as therapeutic targets for the treatment of metabolic diseases such as obesity, In ACC, the biotinoyl domain performs a critical function by transferring an activated carboxyl group from the biotin carboxylase domain to the carboxyl transferase domain, followed by carboxyl transfer to malonyl-CoA. Despite the intensive research on this enzyme, only the bacterial and yeast ACC structures are currently available, To explore the mechanism of ACC holoenzyme function, we determined the structure of the biotinoyl domain of human ACC2 and analyze its characteristics using NMR spectroscopy. The 3D structure of the hACC2 biotinoyl domain has a similar folding topology to the previously determined domains from E. coli and P. Shermanii, however, the 'thumb' structure is absent in the hACC2 biotinoyl domain. Observations of the NMR signals upon the biotinylation indicate that the biotin group of hACC2 does not affect the structure of the biotinoyl domain, while the biotin group for E. coli ACC interacts directly with the thumb residues that are not present in the hACC2 structure. These results imply that, in the E. coli ACC reaction, the biotin moiety carrying the carboxyl group from BC to CT can pause at the thumb of the BCCP domain. The human biotinoyl domain, however, lacks the thumb structure and does not have additional non-covalent interactions with the biotin moiety; thus, the flexible motion of the biotinylated lysine residue must underlie the "swinging arm" motion. This study provides insight into the mechanism of ACC holoenzyme function and supports the "swinging arm" model in human ACCs.

• Analytical Science and Technology
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• v.22 no.6
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• pp.480-487
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• 2009

The herbicide dicamba (2-methoxy-3,6-dichlorobenzoic acid) in soil and plants was determined by gas chromatography-mass spectrometry (GC/MS). The samples were extracted with diethyl ether at pH 2, and washed with 0.1 N HCl, and then dried. The dried residue was derivatized in 1 mL of 10% $H_2SO_4$-MeOH for 2 hr at $80^{\circ}C$. The reaction mixture was neutralized with 4 mL of sodium bicarbonate solution and reextracted with 5 mL of diethyl ether. After the extract was concentrated, dicamba was determined by GC/MS-SIM mode. There was good linearity above 0.999 in the ranges of the $1.0{\sim}100{\mu}g/kg$. Total 42 sample including 32 soil samples and 10 plants samples were analyzed by developed method. Dicamba was detected in the concentration range of $2.9-123.9{\mu}g/kg$ in 15 samples among 32 soil samples and in the concentration range of $43-33,252{\mu}g/kg$ in 5 samples among 10 plants samples. A cause of the wither and die of the pine trees is suspected to spray dicamba around or directly to them.

• The Korean Journal of Pesticide Science
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• v.16 no.1
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• pp.35-42
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• 2012

This study was carried out to elucidate the residual characteristics and calculate processing factors of difenoconazole in ginseng and its processed products, such as dried ginseng, red ginseng and their water and alcohol extracts. The pesticide was sprayed onto the ginseng according to its pre-harvest intervals in 2009 (four-year-old ginseng) and 2010 (five-year-old ginseng). Harvested ginseng was processed to dried ginseng, red ginseng and their extracts according to the commercially well-qualified conventional methods provided by the Korea Ginseng Corporation. Limit of detection (LOD) and limit of quantitation (LOQ) of difenoconazole in fresh ginseng were 0.001 and 0.003 mg/kg, respectively. In case of processed ginseng products, their levels were 0.002 and 0.007 mg/kg, respectively. Concentration of difenoconazole in both fresh ginseng and its processed products increased with the experimental period. Processing factors, calculated as a ratio of difenoconazole concentration in processed products to fresh ginseng were found to be 1.71 to 2.17 and 1.62 to 2.03 in case of dried and red ginseng, respectively, while those for their extracts ranged from 1.76 to 2.98. In case of five-year-old dried ginseng and red ginseng as well as their extracts, the ranges of processing factor of difenoconazole were found to be 2.9 to 3.1, 1.9 to 2.2 and 2.4 to 4.7, respectively.

• Korean Journal of Food Science and Technology
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• v.46 no.1
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• pp.108-114
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• 2014

To analyze the hazards associated with cucumber and hot pepper cultivation areas, a total of 72 samples were obtained and tested to detect the presence of biological (sanitary indicative, pathogenic bacteria and fungi) and chemical hazards (heavy metals and pesticide residues). The levels of sanitary indicative bacteria (aerobic plate counts and coliforms) and fungi were ND-7.2 and ND-4.8 log CFU/(g, mL, hand, or $100cm^2$) in cucumber cultivation areas, and ND-6.8 and 0.4-5.3 log CFU/(g, mL, hand, or $100cm^2$) in hot pepper cultivation areas. More specifically, the soil of hot pepper cultivation areas was contaminated with coliforms at a maximum level of 5.6 log CFU/g. Staphylococcus aureus was detected only in glove samples at a level of 1.4 log CFU/$100cm^2$ and Bacillus cereus was detected in the majority of samples at a level of ND-4.8 log CFU/(g, mL, hand, or $100cm^2$). Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella spp. were not detected. Heavy metal (Zn, Cu, Ni, Pb, and Hg) chemical hazards were detected at levels lower than the regulation limit. Residual insecticides were not detected in cucumbers; however, hexaconazole was detected at a level of 0.016 mg/kg (maximum residue limit: 0.3 mg/kg) in hot peppers.