• Biomedical Science Letters
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• v.22 no.2
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• pp.29-36
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• 2016

Among the several agents causing carbapenem resistance of Acinetobacter baumannii, the most common cause is OXA-23 ${\beta}$-lactamase, which is known to hydrolyze carbapenem. To effectively control dissemination of carbapenem-resistant Acinetobacter baumannii (CRAB), development of both rapid and easy-to-use detection methods are required. The aim of this study is to develop a novel immunochromatographic assay (ICA) for rapid detection of OXA-23 ${\beta}$-lactamase. Of the seven monoclonal antibodies (mAbs) screened by ELISA, four mAbs (4G6, 4H6, 6G4, 9A4) exhibited high reactivity. Of these four specific antibodies, the combination of 6G4/4G6 showed the greatest reactivity and this combination of mAbs (6G4/4G6 mAbs) was used to develop the OXA-23 ${\beta}$-lactamase ICA. Of 102 A. baumannii isolates tested, the OXA-23 ${\beta}$-lactamase ICA results were consistent with PCR analysis except one false positive and one false negative isolate. The overall sensitivity and specificity were 98.36% and 97.56%, respectively. In conclusion, to the best of our knowledge, we have developed the first specific antibody set to detect OXA-23 ${\beta}$-lactamase using an ICA kit. This novel ICA can be used as a reliable and easy-to-use immunological assay for detection of OXA-23 ${\beta}$-lactamase producing CRAB in clinical laboratories.

• Korean Journal of Environmental Agriculture
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• v.13 no.3
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• pp.262-270
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• 1994

The established methods in the residue analysis of endosulfan require an extensive sample clean-up prior to quantification by relatively complex equipment. A radioimmunoassay(RIA) provides a simple procedure with theoretically higher sensitivity and specificity necessitating only a minimum of sample clean-up. Endosulfan-specific antibodies were developed in rabbits by using a bovine serum albumin(BSA) conjugate wherein the alcohol form of endosulfan was multiply bound to the protein via succinylation. Produced antibodies showed the high titers to endosulfan-BSA(1 : 32,000). An RIA method was developed in water and carp by using $^{14}C-labeled$ endosulfan as a tracer. The lowest detection amount of endosulfan was 1 ng in the liver, kidneys, gut and water samples, and 3 ng in the whole body sample of carp without any clean-up, corresponding to 0.1 ppb of endosulfan.

• Tuberculosis and Respiratory Diseases
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• v.42 no.4
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• pp.455-464
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• 1995

Background: Considering that both humoral and cell mediated immunities play an important role for human tuberculosis infection, enzyme-linked immunosorbent assay(ELISA) measurement of immunoglobulin G (IgG) antibody to mycobacterial antigens can be used for the serologic diagnosis of tuberculous pleural effusion. Method: We measured absorbance values of IgG antibodies to purified-protein-derivative (PPD) and lipoarabinomannan-B (LAM-B) in the pleural fluid (PF) and the serum in 40 tuberculous (TPE) and 19 nontuberculous pleural effusions (NTPE). Results: 1) The IgG antibodies to PPD and LAM-B were significantly (P<0.0005) higher in the PF and the serum of TPE compared to NTPE. 2) The IgG antibodies to PPD and LAM-B in the serum were higher than that in PF. 3) Significant correlations were found between pleural and serum IgG antibodies to PPD and LAM-B. 4) With a cutoff value for IgG antibody to PPD in the PF of 0.091, sensitivity was 55.0% and specificity 94.7% in the diagnosis of TPE. 5) With a cutoff value for IgG antibody to LAM-B in the PF of 0.337, sensitivity was 50.0% and specificity 94.7% in the diagnosis of TPE. 6) The seropositive rates in TPE were not related to PPD skin test status, the amount of PF and coexisting active pulmonary tuberculosis. Conclusion: The assay of IgG antibodies to PPD and LAM-B might be useful for the diagnosis of TPE. Our study suggests the mechanism of passive transfer of IgG antibodies to PPD and LAM-B from the serum to the PF through pleural tissue.

• Tuberculosis and Respiratory Diseases
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• v.59 no.2
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• pp.186-192
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• 2005

Background : Diagnosis of tuberculous pleurisy is sometimes difficult using conventional diagnostic methods. We have investigated the utility of pleural fluid cell $IFN-{\gamma}$ production assay in the diagnosis of tuberculous pleurisy. Methods : We prospectively performed pleural fluid cell $IFN-{\gamma}$ production assay in 39 patients with tuberculous pleural effusions (TPE) and in 26 patients with nontuberculous pleural effusions (NTPE) (13 malignant pleural effusions and 13 parapneumonic effusions). Pleural fluid cells were cultured in DMEM media and stimulated with purified protein derivatives (PPD), and phytohemagglutinin (PHA) for 24 hr. The amount of $IFN-{\gamma}$ released in the culture supernatant was quantitated by $IFN-{\gamma}$ ELISA assay. We have also measured adenosine deaminase (ADA) activities and $IFN-{\gamma}$ concentrations in the pleural fluid. Results : 1) The pleural fluid levels of ADA activity and $IFN-{\gamma}$ concentrations were significantly higher in TPE than NTPE (p<0.01). 2) $IFN-{\gamma}$ production in TPE cells stimulated by PPD ($755,266{\pm}886,636pg/ml$) was significantly higher than NTPE cells ($3,509{\pm}6,980pg/ml$) (p<0.01). By considering the fact that $IFN-{\gamma}$ concentrations over 10,000 pg/ml is a criteria for the diagnosis of TBE, sensitivity and specificity of the test were 97.4 and 92.3%, respectively. 3) The ratios of $IFN-{\gamma}$ production by the stimulation with PPD and PHA (PPD/PHA) were significantly higher in TPE cells ($59{\pm}85$) than NTPE cells ($5{\pm}18$)(p<0.01). Considering the criteria for the diagnosis of TBE as PPD/PHA ratio over 5, sensitivity and specificity of the test were 76.9 and 92.3%, respectively. Conclusion : Pleural fluid cell $IFN-{\gamma}$ production assay may be useful for the diagnosis of tuberculous pleurisy.

• Parasites, Hosts and Diseases
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• v.37 no.3
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• pp.163-169
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• 1999

House dust mite allergens have been well established as sensitizing agents that are important in the induction of allergic diseases. In order to analyze epitopes of the allergen and to develop a quantitative method of the allergen exposure, monoclonal antibodies against a recombinant Der p 2 (rDer p 2), one of the major allergens of Dermatophogoides pteronyssinus, were produce. Four monoclonal antibodies produced wee species-specific and did not cross-react to the D. farinae crude extract. Two of the monoclonal antibodies were found to be IgG1 and the others were IgM. For the analysis of epitopes, a Der p 2 cDNA encoding 126 amino acids (aa) was dissected into three fragments with several overlapping peptides, A (aa residues 1-49), B (44-93), and C fragment (84-126). Three monoclonal antibodies showed reactivities to the recombinant B fragment and to the full-length rDer p 2, but one monoclonal antibody reacted only with the full-length rDer p 2. Two-site capture ELISA was developed using two different monoclonal antibodies for quantitating Der p2 in house dust. The sensitivity limit was 4ng/ml with rDer p2 and $8{\;}\mu\textrm{g}/ml$ with the d. pteronyssinus crude extract. The result suggested that the assay using monoclonal antibodies against rDer p2 could be useful for the environmental studies and for the standardization of mite allergen extracts.

• Journal of Veterinary Clinics
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• v.26 no.2
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• pp.130-133
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• 2009

The use of screening tests as part of a diagnostic work-up is common in domestic canine practice, but understanding of the diagnostic test characteristics and factors affecting diagnostic accuracy is not clear among clinicians. This article was aimed to provide clinicians with a better understanding on the selection of test kits and with a proper interpretation of test results using an example from heartworm(Dirofilaria immitis) studies. From the literatures, diagnostic accuracy varied depending on the kits: percent average sensitivity and specificity of ELISA antigen-detecting kits were DiroChek(Synbiotics, USA) 78.1 and 95.2, SNAP(IDEXX, USA) 66.3 and 98.1, and Solo Step(Heska, Switzerland) 69.5 and 97.5, respectively, while the values for three hematological methods(Modified Knott's, direct smear and capillary tube) ranged from 38.4 to 81.8% and from 96.9 to 100%, respectively. Furthermore, it was also reported that the prevalence of heartworm disease in domestic dog populations varied depending on the regions studied: 2.5-22.8% for microfilarial test and 2.2-66.3% by ELISA. The values of predictive values for positive(PPV) and negative(NPV) provide useful information to clinicians on the probability of heartworm infection, but the PPV and NPV are greatly dependent on the heartworm prevalence. This suggests that PPV or NPV values of a test should be interpreted carefully in different clinical settings. Practical methods on the interpretation taking into account heartworm prevalence were discussed.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.2
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• pp.49-53
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• 2016

Acute kidney injury (AKI) is a common syndrome resulting in kidney damage and malfunction within a few days or even a few hours. The diagnosis of AKI depends on routine biochemical tests, including serum creatinine, aspartate aminotransferase (AST), alanine aminotransaminase (ALT), blood urea nitrogen (BUN), and electrolytes. Plasma neutrophil gelatinase-associated lipocalin (NGAL) is a biomarker that shows correlation with the severity of acute infections and kidney injuries. The predictive value in other conventional assays for kidney functions has been reported to cause distraction for AKI syndrome. The aim of this study is to verify the predictive value of plasma NGAL in patients with established AKI. The NGAL kit for checkup demonstrates sensitivity of ${\geq}300$ (92.2%), ${\geq}200$ (95.6%), ${\geq}100$ (99.6%), specificity of ${\geq}300$ (95.1%), ${\geq}200$ (97.3%), ${\geq}100$ (99.4%), positive predictability of ${\geq}300$ (93.3%), ${\geq}200$ (93.4%), ${\geq}100$ (99.2%), and negative predictability of ${\geq}300$ (96.7%), ${\geq}200$ (97.7%), ${\geq}100$ (98.1%), respectively. The plasma NGAL compared with the enzyme-linked immunosorbent assay (ELISA) has been shown to be an early predictive biomarker of AKI. The NGAL kit, recently developed for point-of-care of plasma specimens, is thought to be a useful and reliable biomarker for the early diagnosis of decreased kidney functions.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.23
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• pp.10267-10272
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• 2015

To evaluate the value of combined detection of serum CEA, CA19-9, CA24-2, AFP, CA72-4, SCC, TPA and TPS for the clinical diagnosis of upper gastrointestinal tract (GIT) cancer and to analyze the efficacy of these tumor markers (TMs) in evaluating curative effects and prognosis. A total of 573 patients with upper GIT cancer between January 2004 and December 2007 were enrolled in this study. Serum levels of CEA, CA19-9, CA24-2, AFP, CA72-4, SCC, TPA and TPS were examined preoperatively and every 3 months postoperatively by ELISA. The sensitivity of CEA, CA19-9, CA24-2, AFP, CA72-4, SCC, TPA and TPS were 26.8%, 36.2%, 42.9%, 2.84%, 25.4%, 34.6%, 34.2% and 30.9%, respectively. The combined detection of CEA+CA199+CA242+CA724 had higher sensitivity and specificity in gastric cancer (GC) and cardiac cancer, while CEA+CA199+CA242+SCC was the best combination of diagnosis for esophageal cancer (EC). Elevation of preoperative CEA, CA19-9 and CA24-2, SCC and CA72-4 was significantly associated with pathological types (p<0.05) and TNM staging (p<0.05). Correlation analysis showed that CA24-2 was significantly correlated with CA19-9 (r=0.810, p<0.001). The levels of CEA, CA19-9, CA24-2, CA72-4 and SCC decreased obviously 3 months after operations. When metastasis and recurrence occurred, the levels of TMs significantly increased. On multivariate analysis, high preoperative CA72-4, CA24-2 and SCC served as prognostic factors for cardiac carcinoma, GC and EC, respectively. combined detection of CEA+CA199+CA242+SCC proved to be the most economic and practical strategy in diagnosis of EC; CEA+CA199+CA242+CA724 proved to be a better evaluation indicator for cardiac cancer and GC. CEA and CA19-9, CA24-2, CA72-4 and SCC, examined postoperatively during follow-up, were useful to find early tumor recurrence and metastasis, and evaluate prognosis. AFP, TPA and TPS have no significant value in diagnosis of patients with upper GIT cancer.

• Clinical and Experimental Pediatrics
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• v.51 no.4
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• pp.377-382
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• 2008

Purpose : The aim of this study is to assess the usefulness of skin test by an inactivated, 1/50 diluted solution of attenuated varicella vaccine in evaluating the immune status to varicella. Methods : Total 41 subjects (22 males, 19 females, aged 1-32 years) were enrolled from July to August, 2005. Past medical history including varicella infection, varicella vaccination were investigated through questionnaires. The skin test solution was prepared from solution of attenuated varicella vaccine(Oka strain) which was inactivated by exposure to room temperature for 10 days and diluted at 1/50 with normal saline. Skin test was done by injecting 0.1 mL of the solution intradermally into the volar surface of the right forearm and sterile normal saline was used as a control on the left forearm. Positive reaction was defined when the transverse diameter of the induration was 5 mm or more. Serum varicella zoster virus specific IgG antibody test by ELISA (enzyme-linked immunosorbent assay) was done. Results : In adults, the sensitivity of the varicella zoster virus skin test compared to ELISA was 94.7% and the positive predictive value was 100%. In children, both the positive predictive value and specificity were 100% but the sensitivity and the negative predictive value were 50% and 30.7% respectively. Children showed smaller skin test reactivity compared to adults. Conclusion : The varicella zoster virus skin test using inactivated, 1/50 diluted solution of attenuated varicella vaccine was proved as one of the useful tools for evaluating the immunity and susceptibility of the varicella zoster virus.

• Korean Journal of Poultry Science
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• v.37 no.2
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• pp.167-172
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• 2010

An immunochromatograhy (IC) based infectious bursal disease virus (IBDV) detection kit, which employed two anti-IBDV VP2 monoclonal antibodies, was evaluated for rapid diagnosis of infectious bursal disease virus (IBD). The detection limit of the IC kit for IBDV was $10^{3.1}$ to $10^{3.9}$ $EID_{50}$/mL, indicating that the IC kit detected IBDV sensitively as same as double antigen capture ELISA but less than a RT-PCR assay. The IC kit did not detect other viral pathogens such as Newcastle disease virus, infectious bronchitis, avian influenza virus, and infectious larynotracheitis virus. When applied to tissue samples of experimental chickens died 3 or 4 days post infection after very virulent IBDV (strain Kr/D62) infection, the IC kit detected IBDV in all samples of the bursa of Fabricius, spleen, kidney, cecal tonsil and in 87.5%, 37.5% and 0% of liver, thymus and proventriculus samples. In particular, BF tissue samples showed stronger signal bands than other tissues. Positive signal was observed. All except for one thymus sample of samples having negative results by the IC kit showed the same result with DAS-ELISA but RT-PCR assay detected IBDV in some of IC kit negative samples of thymus and proventriculus. When swab samples from the bursa of Fabricius of dead chickens (n=231) on field farms were tested, the sensitivity and specificity of the IC assay relative to RT-PCR was 100% (109/109) and 97.5% (119/122), respectively and kappa value between both assay was 0.97. The kit can provide a useful aid for rapid detection of IBDV in chickens under field circumstances.