• Proceedings of the Korean Environmental Health Society Conference
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• 2004.06a
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• pp.173-177
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• 2004

The acute toxicities of two major anti-pathogenic veterinary medicines, i.e., ciprofloxacin and enrofloxacin, and six benzimidazole anthelmintics, i.e., albendazole, thiabendazole, flubendazole, febantel, fenbendazole, and oxfendazole, were evaluated with a marine bacterium, Vibrio fischeri, and invertebrate Daphnia magna. These veterinary medical products have been widely used for farm animals, but their impact on aquatic fauna has seldom been investigated. In general, daphnids responded as much as 3 orders of magnitude more sensitively to the tested pharmaceuticals than the microbes. For Daphnia, the most toxic product among the tested anthelmintics was fenbendazole, followed by flubendazole > albendazole ${\approx}$ febantel > thiabendazole > oxfendazole. Daphnids' EC50 values obtained from 48 to 96 hrs of fenbendazole exposure ranged from 2.7 to 6.3 ug/L. The mixture toxicity of the test pharmaceuticals was generally additive in nature and was well predicted by a concentration addition model. Using the predicted no effect concentrations (PNECs) of the benzimidazole derivatives estimated from this study, and predicted environmental concentrations (PECs) of these pharmaceuticals, the risk quotients of each anthelmintics were calculated. Most of the test anthelmintic compounds resulted in risk quotients greater than 1. Especially, risk quotient for fenbendazole was 2,791, which strongly indicates this compound might cause severe ecological consequences, should no future action be taken. This study is the first report on the aquatic toxicities and potential ecological risk of major anthelmintic and antimicrobial veterinary products in Korea. The result of this study provides information necessary for conducting more detailed ecological risk assessment of pharmaceutical products in ambient water and guiding proper management decision.

• Korean Journal of Veterinary Research
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• v.44 no.3
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• pp.455-462
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• 2004

Change in ${\beta}$-tubulin nucleic acid and protein sequences was the only known difference between Haemonchus contortus fenbendazole (FBZ)-resistant and -susceptible isolates. This change was sufficient to determine the pathologic effect induced by FBZ treatment. This research was initiated to investigate further differences from these two isolates. Since ${\beta}$-tubulin is involved in formation of microtubule, which has functions in secretory vesicle transport, DNase activities from excretory/secretory products (ESP) of the two isolates were compared, based on pH, sensitivity to DNase inhibitors, molecular masses and production of 3'-OH. The most significant difference detected was that a 38.5 kDa DNase activity was identified from ESP of H. contortus FBZ-susceptible isolates but not from those of H. contortus FBZ-resistant isolates. However, it was shown that the 38.5 kDa DNase is expressed with similar level of activity in intestine and whole worm of H. contortus FBZ-resistant and -susceptible isolates. This result demonstrated that the secretory transport pathway of the 38.5 kDa DNase was inhibited by unknown mechanisms, which may be related with ${\beta}$-tubulin sequence change in FBZ-resistant isolates. Other DNases of 34, 36 and 37 kDa were detected from ESP of both H. contortus FBZ-resistant and -susceptible isolates. Overall DNase activities found from ESP of these two isolates were not inhibited by 10 mM EDTA at pH 5.0, but largely inhibited by pH 7.0. In addition, DNase activities in two isolates produced DNA fragments with mixtures of 3'- hydroxyls (OH) and 3'-phosphates (P) at each pH although the 3'-end labeling ratios at pH 5.0 and 7.0 were shown different. Identification of inhibition of the 38.5 kDa DNase secretion in FBZ-resistant isolates suggests existence of further differences, in addition to ${\beta}$-tubulin sequence change, in two isolates. This shows complex effect of FBZ on H. contortus biological mechanisms.

• Korean Journal of Veterinary Research
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• v.63 no.1
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• pp.2.1-2.7
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• 2023

Fenbendazole (FBZ) is a benzimidazole anthelmintic widely used to treat parasitic infections. The anticancer effect of FBZ has been recently highlighted leading to its consideration as a potential anticancer agent. Although previous studies have demonstrated the effect of FBZ on cancer cells, there is a paucity of studies on the effect of FBZ on lymphoma cells and normal immune cells. Herein, we investigated the effects of FBZ on a mouse lymphoma cell line, EL-4 cells, and spleen cells, using vincristine as a positive control. The cellular metabolic activity of EL-4 cells was decreased by FBZ, but that of the spleen cells was not decreased. Moreover, FBZ reduced the mitochondrial membrane potential and induced reactive oxygen species production in EL-4 cells, but not in spleen cells. FBZ induced G2/M phase arrest and increased the sub G0/G1 phase ratio, indicating apoptosis. Furthermore, compared to the control cells, the reactivity of spleen cells pretreated with FBZ to lipopolysaccharide was maintained. In summary, FBZ is cytotoxic to EL-4 cells, but not to spleen cells. This study provides experimental evidence that FBZ exerts an anticancer effect, and less cytotoxic effects and functional damage to normal spleen cells.

• Journal of the korean veterinary medical association
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• v.17 no.1
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• pp.51-54
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• 1981

The study was conducted to investigate the effects of Fenbendazol(FBZ) for the control of Cysticercus cellulosae in Jeju native swine. The results abtained were as follows: 1. The swine (S-l) has been 0.1g FBZ/kg body weight for 14 days and slaughtered in

• Korean Journal of Veterinary Service
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• v.44 no.3
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• pp.125-131
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• 2021

Benzimidazole is an widely used anthelmintics in livestock clinics. The aim of present study was to investigate benzimidazole residues in the meat in Sejong City. A total of 338 samples of meat(beef 287, pork 37, chicken 14) were selected from the laboratory meat(Korean beef genetic test, hygiene test) supplied to school in Sejong City. Representative benzimidazole class drug such as thiabendazole, 2-amino albendazole sulfone, fenbendazole, oxfendazole, and oxfendazole sulfone were monitored in samples by using lc-ms/ms and the analysis was preformed based on the Korea Food Code guideline. Limit of quantitation (LOQ) was ranged from 0.56 to 3.02 ppb for target drugs and the accuracy was within the acceptance criteria. Among the sample analyzed only one case, the pork meat was found to have drug levels that exceed LOQ. However, the overall residue concentration was 2.17 ppb, which was lower than the maximum residue levels (100 ppb).

• Journal of fish pathology
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• v.34 no.2
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• pp.261-269
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• 2021

This study presents the evaluation of sample extraction and purification procedure for the determination of residues of febantel and its metabolites, fenbendazole, oxfendazole and oxfendazole sulfone in rockfish (Sebastes schlegeli) muscle using liquid chromatography-tandem mass spectrometry. Residues of febantel and its metabolites in rockfish muscle were analyzed using each different sample preparation method from Korean Food Standards Codex (KFSC), Food Safety and Inspection Service (FSIS, USA), and the modified FSIS method using QuEChERS kit (FSIS-Q), respectively. Each method was compared for mean recoveries and repeatabilities. Since FSIS-Q showed higher repeatabilities (coefficient of variation, CV of 2.4%~10.9%) than those of FSIS method (CV of 4.6%~17.5%), recoveries from FSIS-Q were compared with those from KFSC method. FSIS-Q showed significantly higher recoveries of 83.1%~110.1% (P < 0.05) than those from KFSC method of 64.7%~107.4%. In addition, FSIS-Q showed a good linearity over the range of 2.5~200 ㎍/kg, and excellent sensitivities with limit of detection of 0.46~0.71 ㎍/kg and limit of quantification of 1.08~2.15 ㎍/kg. Although all the sample preparation methods turned out to be able to meet CODEX guideline for all the compounds, FSIS method and FSIS-Q validated in this study could be applied to screening and quantification for residues of febantel and its metabolites in rockfish muscle with efficient preparation procedures.

• Journal of Veterinary Clinics
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• v.38 no.4
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• pp.210-212
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• 2021

A 10-year-old spayed female beagle referred to the Veterinary Teaching Hospital of Chungnam National University presented with acute diarrhea, depression, anorexia, and emaciation. The laboratory findings of the dog showed leukocytosis, high C-reactive protein, and low albumin levels. Fecal examinations revealed severe infection with Strongyloides (S.) stercoralis, with a high fecal score (6/7). Consequently, the dog was diagnosed with hyperinfection of S. stercoralis, and thus, was treated with fenbendazole and ivermectin after discontinuation of prednisolone treatment. The dog showed negative on the Fecal Dx^® Antigen Panel (IDEXX Laboratories Inc., Westbrook, ME, USA) after treatment, and clinical signs disappeared with normal stool consistency.

• Korean Journal of Veterinary Service
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• v.28 no.1
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• pp.81-89
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• 2005

Recently, mass spectrometry coupled with liquid chromatography (LC/MS) has been a preferred technique for determination of organic compounds in complex matrixes. LC/MS provides a high degree sensitivity and specificity of the compounds of interest. The purpose of this study was to confirm analytical method of residual 6 benzimidazoles (thiabendazole, oxfendazole, mebendazole, albendazole, flubendazole and fenbendazole) in meat by LC/MS. Benzimidazoles were analyzed by LC/MS on XTerra $C_{18}$ column with 0.01% trifluoroacetic acid-acetonitrile (TFA) in a gradient mode as mobile phase, and that were identified by electrospray ionization with selected ion recording mode at 150-350 amu mass range. Residual benzimidazoles were extracted from tissue with ethylacetate, and elute benzimidazoles with $50\%$ acetonitrile. In the LC/MS analysis of benzimidazoles, signal to noise ratio was showed relatively high in the positive mode and special ion in the quality analysis was determined via $[M+H]^+$ and Fragment ions. A spectrum of benzimidazoles was showed from all 6 benzimidazoles

• Korean Journal of Veterinary Research
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• v.42 no.2
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• pp.171-181
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• 2002

Simultaneous multiresidue analysis using liquid chromatography determination for five benzimidazole anthelmintics(thiabendazole, oxibendazole, albendazole, mebendazole and fenbendazole) in bovine muscle, liver and omasum has been described. Blank or benzimidazole-fortified samples(0.5g) were blended with bulk $C_{18}$($40{\mu}m$, 18% load, endcapped, 2g). A column made from the resultant $C_{18}$/animal tissue matrix was first washed with hexane($8m{\ell}$), following which the benzimidazoles were eluted with acetonitrile($8m{\ell}$). Analytes of extracted sample were determined by liquid chromatography with UV detector at 290nm. Correlation coefficients of standard curves for individual benzimidazole isolated from fortified samples, using internal standardization, were linear($0.991{\pm}0.007$ to $0.996{\pm}0.005$) with average relative percentage recoveries from $62.1{\pm}3.8(%)$ to $92.3{\pm}7.5(%)$ for the concentration range($0.2{\sim}6.4{\mu}g/g$), respectively. Recoveries rates of TBZ, MBZ in liver, OBZ, MBZ in muscle and TBZ, MBZ in omasium from fortified benzimidazole were 92.%, 87.3%, 74.5%, 82.7%, 75.2% and 83.5% at condition II, respectively. Condition II showed higher recoveries rates than condition I. These results indicated that the matrix solid phase dispersion(MSPD) methodology is acceptable for the determination of 5 benzimidazole anthelmintics and may also suitable for other matrixes of food animal origin.