• Korean Journal of Food Science and Technology
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• v.38 no.3
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• pp.317-324
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• 2006

Pesticide residues were monitored in agricultural products purchased at Gyeongin and Jeolla-do provinces. Total 245 pesticides were analysed by GC-MS and LC-MS/MS, and residual pesticides were detected in 70 samples (19.7%), with spinach and chard showing high detection frequency of 35%. Fifteen samples (4.2%) exceeded Korea Maximum Residue Limits (MRLs), and 30 types of pesticides were detected in samples with azoxystrobin, procymidine, endosulfan showing considerably high frequencies in respectively 14, 13, and 13 samples. The amount of 11 pesticide including chlorpyrifos, indoxacarb among them were detected over Korea MRLs. No residual pesticides were detected in 285 (80.3%) samples, and residual pesticides levels of 55 samples (15.5%) were lower than Korea MRLs, indicating 95.8% samples were relatively safe.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 1997.10a
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• pp.37-39
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• 1997

Pesticide residues were extracted with 70% acetone and transferred to dichloromethane. Extracts were applied to open-column chromatography with florisil and alumina-N, The final extract was analyzed by gas chromatography with electron-capture detector(GC/ECD) and nitrogen-phosphorus detector(GC/NPD). Recoveries of the 17 organochlorine pesticides were ranged from 60.8 to 84.9% and those of 15 organophosphorus pesticides, from 70.5 to 100.0%(except phosmet and azinphos-methyl). The minimum detectable levels of this analytical method were low (0.021-0.058 mg/kg).

• Analytical Science and Technology
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• v.23 no.4
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• pp.395-404
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• 2010

A multi-residual method using gas chromatography coupled with mass spectrometry (GC/MS/ MS) was developed for the analysis of 105 pesticides. This method was tested on lemons, beans and other vegetables. The pretreatment of these pesticides was performed by liquid-liquid partition followed by cleanup with solid phase extraction cartridge (SPE Florisil), after acetonitrile extraction from matrices and sodium chloride (15 g) addition. The recovery ranged from 71.1% to 126.0% except for azinphosmethyl, famoxadone, fenamidone, flufenoxuron and triadimefon in lemons and from 72.5% to 124.5% in bean. In lemon, the limit of detection (LOD) and limit of quantification (LOQ) were 0.001~150 ng/ mL and 0.004~500 ng/mL, respectively.

• Journal of Microbiology and Biotechnology
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• v.24 no.7
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• pp.905-913
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• 2014

Lj-RGD3, an RGD (Arg-Gly-Asp) toxin protein from the salivary gland of Lampetra japonica, exhibits antifungal activity against Candida albicans. Lj-RGD3 has three RGD motifs and shows homology to histidine-rich glycoprotein. We synthesised two mutant derivatives of Lj-RGD3: Lj-26, which lacks all three RGD motifs and contains no His residues; and Lj-112, which lacks only the three RGD motifs. We investigated the effects of the wild-type and mutated toxins on a gram-positive bacterium (Escherichia coli), a gram-negative bacterium (Staphylococcus aureus), and a fungus (C. albicans). rLj-RGD3 and its mutants exhibited antifungal but not antibacterial activity, as measured by a radial diffusion assay. The C. albicans inhibition zone induced by rLj-112 was larger than that induced by the other proteins, and its inhibitory effect on C. albicans was dose-dependent. In viable-count assays, the rLj-112 MIC was $7.7{\mu}M$, whereas the MIC of the positive control (ketoconazole) was $15{\mu}M$. Time-kill kinetics demonstrated that rLj-112 effectively killed C. albicans at $1{\times}$ and $2{\times}$ MIC within 12 and 6 h, respectively. Electron microscopy analysis showed that rLj-RGD3 and rLj-112 induced C. albicans lysis. Our results demonstrate a novel anticandidal activity for rLj-RGD3 and its mutant derivatives.

• Journal of Photoscience
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• v.11 no.1
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• pp.29-33
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• 2004

The mechanism of interaction of cyanocobalamin (CB) with bovine serum albumin (BSA) has been investigated by spectrofluorometric and circular dichroism methods. Association constant for the CB-BSA system showed that the interaction is non-covalent in nature. Binding studies in the presence of an hydrophobic probe, 8-anilino-l-naphthalene sulphonic acid, sodium salt (ANS) showed that there is hydrophobic interaction between CB and ANS and they do not share common sites in BSA. Stern-Volmer analysis of fluorescence quenching data showed that the fraction of fluorophore (protein) accessible to the quencher (CB) was close to unity indicating thereby that both tryptophan residues of BSA are involved in drug-protein interaction. The rate constant for quenching, greater than $10^{10}$ $M^{-1}$ $s^{-1}$, indicated that the drug binding site is in close proximity to tryptophan residue of BSA. Thermodynamic parameters obtained from data at different temperatures showed that the binding of CB to BSA involves hydrophobic bonds predominantly. Significant increase in concentration of free drug was observed for CB in presence of paracetamol. Circular dichroism studies revealed the change in helicity of BSA due to binding of CB to BSA.

• Journal of Pharmaceutical Investigation
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• v.24 no.4
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• pp.217-225
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• 1994

With the purpose of improving the therapeutic index of $[^3H]$ acyclovir (ACV) in the treatment of chronic hepatitis B infection, asialofetuin (AF) which after selective interaction with Ashwell's receptor specifically enters into hepatocytes, was chosen as a carrier system for hepatic targeting. This drug was first converted to its monophosphate (ACVMP), which was subsequently activated by water soluble carbodiimide to conjugate with ${\varepsilon}-NH_2$ groups of Iysine residues of AF. The molar ratio of ACVMP to AF in the conjugate was 3.9. In rats, elimination of ACVMP-AF conjugate after i.v. injection showed two phase elimination kinetics. Initial apparent elimination rate constant in rats was $0.191\;min^{-1}$ which was greater than that of ACV. The elimination rate constant from terminal phase was $0.021\;min^{-1}$. Area under the total radioactivities versus time curve was found to be several times larger in liver than in other organs (spleen, intestine, lung and kidney) after i.v. administration of the conjugate labelled in the drug moiety. The above results suggested that ACVMP-AF conjugate was rapidly taken up by hepatocytes and could be a useful hepatic targeting system.

• Fisheries and Aquatic Sciences
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• v.22 no.12
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• pp.29.1-29.7
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• 2019

Veterinary drugs are widely used to protect production-related diseases and promote the growth of farmed fish. The use of large amounts of veterinary drugs may have potential risk and cause adverse effects on both humans and the environment. In this study, we developed risk-based ranking based on a scoring system to be applied in the national residue program. In this approach, the following three factors of veterinary drugs that may occur as residues in fishery products were considered: potency (acceptable daily intake), usage (number of dose and withdrawal period), and residue occurrence. The overall ranking score was calculated using the following equation: potency × usage (sum of the number of sales and withdrawal period) × residue occurrence. The veterinary drugs that were assigned high score by applying this approach were enrofloxacin, amoxicillin, oxolinic acid, erythromycin, and trimethoprim. The risk-based approach for monitoring veterinary drugs can provide a reliable inspection priority in fishery products. The developed ranking system can be applied in web-based systems and residuemonitoring programs and to ensure safe management of fishery products in Korea.

• Korean Journal of Veterinary Service
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• v.25 no.3
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• pp.299-308
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• 2002

The purposes of this study were to characterize the disposition of sulfathiazole(ST) and to investigate the effects of sodium bicarbonate on the disposition of ST in broiler chicks(2.5～3.0kg). Animals were given ST acutely(10～80mg/kg, PO), and plasma, kidney, muscle, heart, liver and spleen samples were collected and analyzed for ST by high performance liquid chromatography. The plasma and tissue data was consistent with a one-compartment pharmacokinetic model. The drug is rapidly but incompletely(2.5～3.87%) absorbed with peak plasma and tissue levels being achieved within one hour after dosing. The plasma and tissue levels depended on drug dosage, and the descending order in concentration of ST was kidney > plasma > heart > muscle $\geq$ spleen $\geq$ liver from animals sacrificed at one hour after dosing. Moreover, significant positive correlations(r>0.9) existed between plasma and tissue levels of ST. In addition, sodium bicarbonate pretreatment decreased plasma level, indicating that an alkalinization stimulate the excretion of ST. Results of this study suggest that oral application of ST was rapidly absorbed and eliminated, and confirmed that tissue residues of ST can be estimated from plasma drug concentration in broiler chicks.

• Journal of Integrative Natural Science
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• v.5 no.1
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• pp.22-26
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• 2012

Chemokine receptor antagonists have potential applications in field of drug discovery. Although the chemokine receptors are G-protein-coupled receptors, their cognate ligands are small proteins (8 to 12 kDa), and so inhibiting the ligand/receptor interaction has been challenging. In particular, CCR2 and CCR5 and their ligands have been implicated in the pathophysiology of a number of diseases, including rheumatoid arthritis and multiple sclerosis. Based on their roles in disease, they have been attractive targets for the pharmaceutical industry, targeting both CCR2 and CCR5 could be a useful strategy. Because of the importance of these receptors, providing information regarding the binding site is of prime importance. Herein, we report the comparison of CCR2 of CCR5 binding sites both sequentially as well as structurally. We also urged the importance of crucial residues in the binding site, to facilitate the development of dual antagonists targeting both the receptors. These results could also be useful for the design of novel and potent dual CCR2 and CCR5 antagonists using structure based drug design.

• Journal of Environmental Science International
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• v.15 no.2
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• pp.163-167
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• 2006

To obtain the safety evaluation of the ginseng, residues of heavy metals in culture environment of ginseng on Punggi and Sangju, Kyeongbuk are surveyed. The concentration for component of ginseng on Punggi and Sangju were 14.12mg/kg and 15.74mg/kg, respectively. The concentration for general component such as crude fiber, ash, crude lipid, crude protein, carbohydrate, of ginseng were coincided between Punggi and Sangju. The concentration for As, Pb, Cd, and Hg in soil on Punggi were 14.24 ppb, 43.13 ppb, 8.73 ppb and 0.82 ppb, respectively. The concentration for As, Pb, Cd, and Hg in soil on Sangju were 19.20 ppb, 54.82 ppb, 15.90 ppb and 1.04, respectively. Residual heavy metals are not polluted in the soil with culture ginseng on Punggi and Sangju. The concentration for As, Pb, Cd, and Hg with ginseng on Punggi were 29.30ppb, 21.78 ppb, 1.32 ppb and 2.72 ppb, respectively. The concentration for As, Pb, Cd, and Hg with ginseng on Sangju were 3.22 ppb, 24.43 ppb, 1.44 ppb and 4.74 ppb, respectively. Also the detection concentration for As, Pb, Cd, and Hg in ginseng were also lower than the Korea Food & Drug Administration advisory level for heavy metal in herbal medicines. Residual heavy metals are not polluted in the ginseng on Punggi and Sangju at Kyeongbuk, Korea.