• Korean Journal of Veterinary Research
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• v.28 no.2
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• pp.321-325
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• 1988

This experiment was carried out to determine the progesterone concentration of bovine plasma by liquid phase double antibody enzyme immunoassay. The optimum conditions of assay-system, double (first and second) antibody and carrier (normal rabbit serum) were investigated. The optimum dilution rate of first antibody, second antibody and normal rabbit serum was $10{\times}10^3$ to $15{\times}10^3$, 20 and $1{\times}10^3$ times, respectively.

• Korean Journal of Veterinary Research
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• v.29 no.1
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• pp.21-25
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• 1989

This experiment was carried out to determine the progesterone concentration of bovine plasma by liquid phase double antibody enzyme immunoassay. The optimum conditions of assay-system, enzyme conjugate and gelatin were invested. The sensitivity, recovery rate and reproducibility by this assay were also analyzed. The results obtained were as follows: 1. The suitable supplementation level of gelatin was 0.2%. As the gelatin level increased to 1%, coefficient variation of interassay was shown to be irregular. 2. The optimum dilution rate of enzyme conjugate was 30 times. Enzyme activity was greatly fluctuated depending on the minor condition of enzyme conjugate technique. Therefore, it was considered to be checked when determined. 3. The sensitivity of the assay was 12 pg/tube. 4. Recovery rate was decreased when the amount of sample was too little or too much, but the recovery rate was high as 97.8% when the amount of sample between 50 and $200{\mu}l$. 5. Mean intra-assay and inter-assay coefficient of variation was 4.5% and 5.9%, respectively. By using liquid phase double antibody enzyme immunoassay, progesterone in plasma can be detected, and also this assay system is applicable to study on physiological function of progesterone and to diagnosis of reproductive disorders.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.7 no.2
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• pp.153-162
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• 2004

Purpose: The Helicobacter pylori stool antigen (HpSA) enzyme immunoassay is a non-invasive test for the diagnosis and monitoring of H. pylori infection. But, there are few validation studies on the HpSA test after eradication in children. The aim of this study was to assess the diagnostic accuracy of HpSA enzyme immunoassay for the detection of H. pylori to confirm eradication in children. Methods: From January 2001 to October 2003, 164 tests were performed in 146 children aged 1 to 17.5 years (mean $9.3{\pm}4.3$ years). H. pylori infection was confirmed by endoscopy-based tests (rapid urease test, histology, and culture). All H. pylori infected children were treated with quadruple regimens (Omeprazole, amoxicillin, metronidazole and bismuth subcitrate for 7 days). Stool specimens were collected from all patients for the HpSA enzyme immunoassay (Primier platinum HpSA). The results of HpSA tests were interpreted as positive for $OD{\geq}0.160$, unresolved for $$0.140{\leq_-}OD$$<0.160, and negative for OD<0.140 at 450 nm on spectrophotometer. Results: 1) One hundred thirty-one HpSA tests were performed before treatment. The result of HpSA enzyme immunoassay showed three false positive cases and one false negative case. The sensitivity, specificity, positive predictive value, and negative predictive value of HpSA enzyme immunoassay before treatment were 96.4%, 97.1%, 90%, and 99%, respectively. 2) Thirty-three HpSA enzyme immunoassay were performed at least 4 weeks after eradication therapy. The results of HpSA enzyme immunoassay showed two false positive cases and one false negative case. The sensitivity, specificity, positive predictive value, and negative predictive value after treatment were 88.9%, 91.7%, 80%, and 95.7%, respectively. Conclusion: Diagnostic accuracy of the HpSA enzyme immunoassay after eradication therapy was as high as that of the HpSA test before eradication therapy. The HpSA enzyme immunoassay was found to be a useful non-invasive method to confirm H. pylori eradication in children.

• Microbiology and Biotechnology Letters
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• v.17 no.4
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• pp.365-369
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• 1989

Thermal inactivation of Tyichoderma viride cellobiohydrolase was investigated by immunoassay and residual enzyme assay such as carboxymethyl cellulase (CMCase) and filter paper degradation activity (FPase). Arrhenius plots of cellobiohydrolase were appeared as straight line. The Z-values of cellobiohydrolase calculated by CMCase, FPase and immunoassay were 5.2$^{\circ}C$, 6.4$^{\circ}C$ and 5.8$^{\circ}C$, respectively. The thermodynamic parameters obtained from FPase were better agreement with those of immunoassay than CMCase assay.

• The Journal of the Korean Society for Microbiology
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• v.22 no.4
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• pp.445-451
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• 1987

Coagglutination method is widely used for the diagnosis of Salmonella infection. This test, however, has a disadvantage of false positive reaction due to the coagglutination of staphylococci with non-specific immune complexes or anti-staphylococci antibody in serum. Salmonell O antigen was detected by enzyme immunoassay with protein A-bearing Staphylococcus aureus as in the solid phase. Horse radish peroxidase was labeled to IgG specific against Salmonella O antigen. This enzyme immunoassay was much more sensitive than conventional coagglutination method without false poitive agglutination. To improve the sensitivity for detection of Salmonella O antigen in samples, we tried to determine the optimal concentration of normal IgG that inhibits non-specific binding of horse radish peroxidase labeled IgG to staphylococci, and to establish the optimal condition of reaction between antigen-antibody complex and staphylococci. Non-specific binding of horse radish peroxidase labeled specific IgG to staphylococci was almost blocked when the enzyme labeled IgG was 500-fold diluted with phosphate buffered saline containing 2mg/ml of normal IgG. When staphylococci coated with antibody to Salmonella O antigen were mixed with antigen-antibody complex and then incubated for 1 hour at room temperature, the minimal detectable concentration of Salmonella O antigen was 1ng/ml. The sensitivity of enzyme immunoassay was 100-fold greater than a conventional coagglutination method. This enzyme immunoassay could be expected as an improved method for detection of other infectious agents.

• BMB Reports
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• v.34 no.1
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• pp.47-50
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• 2001

A one-step, two-site enzyme immunoassay was developed for measuring human alpha-fetoprotein (AFP) in serum and amniotic fluid using monoclonal antibodies (McAb) by eliminating the high-dose hook effect. Three McAbs that recognize different epitopes were selected among 16 different clones on the basis of epitope mapping, two for immobilization and one for horseradish peroxidase conjugation. This one-step immunoassay system is more convenient and rapid compared to a conventional two-step sandwich immunoassay system. It did not exhibit the hook effect to around 2.7 mg/ml of AFP, which is probably one of the highest concentrations of AFP in the serum. The dose-response curve of the system was linear to 500 mg/ml of AFP and the system could differentiate as low as 1 mg/ml of AFP The intra- and inter-assay variations were in an acceptable range; 95~104% and 97~105% respectively Its correlation with other commercial systems was around 95%.

• Molecules and Cells
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• v.21 no.2
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• pp.308-313
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• 2006

Amygdalin is a cyanogenic glycoside compound which is commonly found in the pits of many fruits and raw nuts. Although amygdalin itself is not toxic, it can release cyanide (CN) after hydrolysis when the pits and nuts are crushed, moistened and incubated, possibly within the gastrointestinal tract. CN reversibly inhibits cellular oxidizing enzymes and cyanide poisoning generates a range of clinical symptoms. As some pits and nuts may contain unusually high levels of amygdalin such that there is a sufficient amount to induce critical CN poisoning in humans, the detection of abnormal content of amygdalin in those pits and nuts can be a life-saving measure. Although there are various methods to detect amygdalin in food extracts, an enzyme immunoassay has not been developed for this purpose. In this study we immunized New Zealand White rabbits with an amygdalin-KLH (keyhole limpet hemocyanin) conjugate and succeeded in raising anti-sera reactive to amygdalin, proving that amygdalin can behave as a hapten in rabbits. Using this polyclonal antibody, we developed a competition enzyme immunoassay for determination of amygdalin concentration in aqueous solutions. This technique was able to effectively detect abnormally high amygdalin content in various seeds and nuts. In conclusion, we proved that enzyme immunoassay can be used to determine the amount of amygdalin in food extracts, which will allow automated analysis with high throughput.

• Korean Journal of Veterinary Research
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• v.32 no.3
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• pp.429-434
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• 1992

This study was carried out to develop an effective liquid-phase double antibody enzyme immunoassay for determining of progesterone. The optimum conditions of assay system, 1st and 2nd antibodies, enzyme conjugate, and time reaction were invested. The bovine plasma progesterone level in dairy cattle and korean native bulls were also analyzed. The results obtained were as follows; 1. The reproducibility of petroleum ether was superior to that of ethyl ether as extract solvent of progesterone in plasma. 2. The optimum dilution rate of 1st and 2nd antibody was 30,000 and 10 times, respectively. Affer the reaction of enzyme conjugate to progesterone 1st antibody, and then 2nd antibody competition reaction was enough for over 1hr. 3. Average plasma progesterone level in 4 pregnant and 9 nonpregnant Holstein was $2.5{\pm}0.5$ and $0.7{\pm}0.2ng/m{\ell}$, respectively. Average plasma progesterone level of 10 Korean native bulls was $0.1{\pm}0.001ng/m{\ell}$ From these results, by using liquid phase double antibody enzyme immunoassay for progesterone is applicable to detect of early pregnancy diagnosis, factorial analysis of reproductive disorder, and also reproductive physiological function such as monitoring of cyclicity during the post-partum period.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.439-443
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• 2000

In order to evaluate the safety of greenhouse horticulture products in Korea, we carried out this work by screening of Fusarium species, which produce deoxynivalenol (DON) from greenhouse horticulture in Western Gyeongnam and Northern Gyeongbuk, Korea. For this study, high sensitive enzyme-linked immunosorbent assay, ALP/NADP method, was applied to detection of DON by enzyme amplification system. From 192 samples of greenhouse horticulture soil and its products, 103 isolates of Fusarium species were obtained. The isolates were cultured at 28C for 15 days and the cultured mediums were extracted by ethyl acetate. The production of DON was verified by thin layer chromatography (TLC). As the results of TLC, 8 strains were identified as DON producing strain. We screened potential producers of DON by ALP/NADP. The levels of DON production were shown from 0.007 to 1.21 g/ml of YES medium. The maximum DON producing strain No. 32-D-3 was isolated from soil in Namhae, Korea. In conclusion, the above results indicate that DON producing fungi contaminated greenhouse horticulture products in Korea. Therefore, further studies are required to accumulate more detailed data about the contamination of DON in various cereals.

• Journal of Microbiology and Biotechnology
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• v.17 no.6
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• pp.1002-1009
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• 2007

A rapid, convenient homogeneous competitive enzyme immunoassay for estimating the amount of fenthion is described. The assay utilizes glucose-6-phosphate dehydrogenase-hapten conjugates that are inhibited in solution by antibodies obtained from bovine serum albumin-hapten conjugates. In order to investigate the effects of bridging group recognition on the sensitivity of dose response characteristics, the bridging groups of varying alkyl chain length were attached at the phosphate position of fenthion. Among the antibodies used, the one obtained from the use of hapten (fenthion analog) with the same bridging group structure that was used in preparing the enzyme-fenthion conjugates showed maximum inhibition (up to 51.8%) in the absence of fenthion. In the presence of fenthion, the activity of the enzyme-hapten conjugate is regained in an amount proportional to the fenthion concentration. Under the optimized condition, the $ED_{50}$ value for fenthion was $0.809{\mu}g/ml$. The assay developed in this study is a rapid effective screening method for fenthion prior to precise analysis.