• Korean Journal of Veterinary Service
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• v.22 no.1
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• pp.93-101
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• 1999

This test process on screening method for the detection of residual antibiotics in milk is simple, economic, sensitive to residual antibiotics and was given approval international organs. Thus, this study was carried out the comparison of Disk assay method and TTC-II method for sensitivity and minimum detectable range of antibiotics in raw milk. The results of this study was summarized as follows ; 1. The number of samples requested for treatment of mastitis was 198 samples. Comparison or analytical results among the methods of TTC-II, disk assay and Delve sp was that TTC-II 37 samples(18.6% ), Disk assay 125samples(63.1%), Delve SP 130 samples(65.7% ) reacted positively. Conformity rate of Delve SP and Disk assay was 70%. 2. Detectable limits of disk assay method in some antibiotics were more sensitive than those of official method(0.05-0.0025ppm in the $\beta$-lactams, 1ppm in two aminoglycoside, 0.2 ppm in one tetracycline, similar in one macrolide) 3. For sensitivity of residual sulfonamides TTC-II was much more sensitive than disk assay. Detectable limits of sulfamethazine and sulfadimethoxine were 30 to 50ppm levels. 4. The best medium preservation period is 1-2 days. 5. Concentration of brome cresol purple related to resistance for B stearothermophilus culture was 24ppm/ml. These results show that disk assay method for screening detection of antibiotics residuces in milk is worthy of use.

• Biomolecules & Therapeutics
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• v.13 no.1
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• pp.59-63
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• 2005

A kinetic assay was carried out in order to compare the ability of detection for prekallikrein activator(PKA) in plasma-derived products with that of an endpoint assay and a commercial method. Using these methods, 9 human albumin preparations were assayed and compared to each other. The coefficient of variation between the Kinetic assay and the end point assay was found within 6.6% and this result showed that two methods were highly correlative and the end point assay could act as a replacement of the kinetic assay. Another important goal of this study was to investigate the reproducibility among laboratories on the kinetic assay. A collaborative study was performed to validate the kinetic method with intra and inter assays. The coefficient of variation for the intra assay of each laboratory was less than 4% and that for between individuals in the inter assay was 4.1%. These results revealed that the kinetic assay showed good reproducibility. The contents of PKA in plasma-derived products were also determined by the kinetic assay. As a result, it was found that trace amounts of PKA were present in 32 human immunoglobulin preparations, however the average concentration of PKA in 171 albumin preparations was 5.8 IU/mL.

• Journal of Pharmaceutical Investigation
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• v.21 no.3
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• pp.179-188
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• 1991

An HPLC assay method of a drug to be applied to the pharmacokinetic studies of the drug should be completely validated. The validation process for an HPLC assay method in a biological sample was discussed using the data obtained from the development of HPLC method for the simultaneous quantitation of verapamil and norverapamil in human serum. The validation criteria included were specificity, linearity, accuracy, precision, sensitivity, recovery, drug stability, and ruggedness of an assay method.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.15 no.1
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• pp.37-50
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• 1989

The in Vitro chemosensitivity of fibroblast cell strains was determined using a semiautomated tetrazolium-based colorimetric assay(MTT assay) to 16 cosmetic materials. This assay is useful method to evaluate toxic effects of the chemicals. From assay results, we determined that the preservatives are more toxic than moisteurizers. The chemicals in the same group have a different toxicity. That is, in preservatives, Germall -115 is more toxic than Danisol -M, -p, and in surfactant sodium laurel sulfate than Myrj 52, and in moisteurizers, 1, 3-butylene glycol is more safe than the others. When the results from this assay for preservatives were compared with patch test results, good correlation was observed. Forthemore, this assay method can be used together with Patch test for the evaluation of the chemical toxicity, particularly in cosmetic field.

• Journal of Korean Society of Water and Wastewater
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• v.36 no.3
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• pp.177-186
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• 2022

In this study, newly improved Ferron assay test haved on timed spectrometry was used for the determination of hyolrolytic Al species presented in PACl coagulant. The color development reagent ferron was prepared by using conventional method and two newly developed methods. Then the ferron assay test was used to compare and analyze the distribution of Al(III) hydrolyzed species presented in the prepared PACl and alum. The preparing method of reagent A required an aging period of 7 days by adding a hydroxylamine hydroxide and a 1,10-phenanthroline monohydrate reagent, whereas the preparing method of reagent B was used as a coloring agent immediately without aging time. The regression analysis between UV absorbance and Al concentrations of conventional method and newly developed method of ferron reagents in low-concentration aluminum solutions and high-concentration aluminum solutions, showed the correlation coefficients of 0.999 or higher, as showing high correlations of conventional method and newly developed method. Applying Ferron assay test, Al species in the PACls and alum were classified as Ala(monomeric Al), Alb (polymeric Al), and Alc (colloidal and precipitated Al). Distribution of Al(III) hydrolyzed species according to the preparation of ferron colorimetric reagents was similar.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1345-1348
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• 1999

The utility of a bioluminescence adenosine triphosphate(ATP) assay method for estimating bacterial levels in mackerel(Scomber japonicus) was investigated. Mackerel was stored at $1^{\circ}C$ throughout 10 days and its RLU(relative light unit) and APC(aerobic plate count) was determined. The ATP bioluminescence assay was validated during the storage of 32 samples, resulting in an agreement between the ATP assay and standard plate count methods of over 90% credibility. Therefore, ATP bioluminescence assay was considered as a rapid and near real-time means in estimating the microbial load on mackerel skin.

• Journal of Microbiology
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• v.38 no.2
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• pp.74-79
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• 2000

For the demonstration of a novel riboflavin kinase assay method based on the bacterial bioluminescence, partially purified riboflavin kinase was prepared from bovine liver through ammonium sulfate precipitation and DEAE-cellulose ion exchange chromatography. Using bacterial luciferase from Photobacterium phosphoreum and the dithionite reduction method, and easy, safe, and fast assay method was established. The optimal temperature, pH, Km values form riboflavin and ATP of boving liver riboflavin kinase determined with this luminescence method were 35$^{\circ}C$, pH 7, 15.3${\mu}$M and 8.3.${\mu}$M, respectively. The detection limit of FMN produced by riboflavin kinase was in the range of 200 pM to 4${\mu}$M which is comparable to the HPLC-fluorescence detection method, while the detection time for each assay was less than 15 sec compared to the HPLC method which requeires at least 10 min for completion.

• BMB Reports
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• v.30 no.6
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• pp.443-447
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• 1997

We have developed a novel method for assays of spermidine and spermine synthase (aminopropyltransferase) activities using antibody against 5'-deoxy-5'-methylthioadenosine (MTA). A new assay is reported here which is based on the observation that MTA is formed as a stoichiometric by-product of the spermidine and spermine synthases reactions. In order to determine MTA, a radioimmunoassay method with sensitivity and rapidity was used. (Lee and Cho, 1997). In this assay, adenine must be added in the reaction mixture, since it effectively inhibits the action of MTA phosphorylase by which MTA is metabolized. This assay is a improvement in term of sensitivity and time saving, compared to the currently used methods. It has a level of sensitivity (100 fmol) sufficient to monitor aminopropyltransferase activities in incubations containing as little as $10{\mu}g$ protein prepared from rat tissue homogenate. The results obtained showed that this method is particularly useful for cultured cells with low enzyme concentration. Moreover, this assay has the advantage which allows studies using alternative substrates (other amines). Spermidine synthase activity was high in rat liver, but low in rat kidney. The activity of spermine synthase was in most rat tissues very low as compared to that of spermidine synthase, but was high in brain.

• Microbiology and Biotechnology Letters
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• v.19 no.4
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• pp.372-379
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• 1991

A rapid and simple quantitative assay method for aminoglycoside-3'- phosphotransferase (APH(3')) derived from E. coli ATCC 21990 was developed using the thin layer chromatographic densitometry, 3'-phosphorylated kanamycin B (3'-PKMB), product of APH (3') reaction, was separated from reaction mixtures by developing on the silica gel TLC plate with chloroform-methanol-ammonia water (3:4:3). The quantity of the 3'-PKMB was measured by densitometry after color development by ninhydrin method. Densitometric TLC assay for APH (3') was showed a good quantitative result and reproducibility. Sensitivity of this assay was 1.56 nmol of 3'-PKMB and could be analyzed many samples at same time. This method may be applicable for the analysis of inactivating enzymes of aminoglycoside antibiotics.

• Journal of Microbiology and Biotechnology
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• v.20 no.3
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• pp.569-573
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• 2010

A quantitative detection method for Salmonella in seafood was developed using a SYBR Green-based real-time PCR assay. The assay was developed using pure Salmonella DNA at different dilution levels [i.e., 1,000 to 2 genome equivalents (GE)]. The sensitivity of the real-time assay for Salmonella in seeded seafood samples was determined, and the minimum detection level was 20 CFU/g, whereas a detection level of 2 CFU/ml was obtained for pure culture in water with an efficiency of ${\geq}85%$. The real-time assay was evaluated in repeated experiments with seeded seafood samples and the regression coefficient ($R^2$) values were calculated. The performance of the real-time assay was further assessed with naturally contaminated seafood samples, where 4 out of 9 seafood samples tested positive for Salmonella and harbored cells <100 GE/g, which were not detected by direct plating on Salmonella Chromagar media. Thus, the method developed here will be useful for the rapid quantification of Salmonella in seafood, as the assay can be completed within 2-3 h. In addition, with the ability to detect a low number of Salmonella cells in seafood, this proposed method can be used to generate quantitative data on Salmonella in seafood, facilitating the implementation of control measures for Salmonella contamination in seafood at harvest and post-harvest levels.