• Title/Summary/Keyword: False negative reactions

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Noninvasive Detection of Specific Diagnostic Biomarkers for Atopic Dermatitis

  • Chang, Jeong Hyun
    • Biomedical Science Letters
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    • v.25 no.1
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    • pp.15-22
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    • 2019
  • The diagnosis of atopic dermatitis (AD) includes a test that checks allergen-mediated skin reactions and a method of measuring the total IgE and allergen-specific IgE in blood. However, these test methods are performed directly on the patient, which cause some pain or discomfort. In addition, the skin response test or IgE may result in false negative in about 20% of patients. In the present study, to identify specific biomarkers, HaCaT cells were used as a human keratinocyte that make up the skin, were treated IL-4 and IL-13 for 24 hours to induce a situation similar to keratinocytes in AD patients. In the HaCaT cells, pro-inflammatory cytokine such as IL-5, IL-6, and MCP-1 were increased by IL-4 and IL-13 and skin barrier proteins was reduced by IL-4 and L-13. This results showed that a situation similar to the stratum corneum of an actual patient is induced in HaCaT cells. And then the secretions of Kallikrein (KLK) 5 and KLK7 protease were checked by enzyme-linked immunosorbent assay (ELISA). It was specifically increased by IL-4 and IL-13. This showed that AD-related protease can be detected at the protein level using keratinocytes that can be taken in a non-invasive manner and suggested the possibility of applying it to AD diagnosis.

Evaluation of Enzyme-linked Immunosorbent Assay in Serological Diagnosis of Human Neurocysticercosis using paired Samples of Serum and Cerebrospinal Fluid (면역효소측정법을 이용한 뇌낭미충증의 혈청학적 진단의 평가)

  • 조승열;김석일
    • Parasites, Hosts and Diseases
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    • v.24 no.1
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    • pp.25-41
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    • 1986
  • The applicability of micro-ELISA was evaluated in human neuro-cysticercosis using paired samples of serum and CSF. A total of 355 cases who were mostly neurologic patients was subjected. Cystic fluid of C. cellulosae was used as antigen in protein concentration of $2.5{\;}{\mu}g/ml$. Serum was diluted to 1 : 100 and CSF was undiluted in the assay for the specific IgG antibody level. The differential criterion of the positive reaction was the abs. of o. 18 in both samples. The results were summarized as follows: 1. The overall sensitivity of the micro-ELISA in 71 confirmed neurocysticercosis was 90.1% ; the sensitivity by serum was 77.5% and that by CSF was 83.1%. CSF was a more sensitive and valuable material. Most of the false negative cases of neuro-cysticercosis showed far lower level of abs. rather than marginal. 2. The overall specificity of the micro-ELISA in 52 confirmed other neurologic diseases was 88.5%; the specificities by serum and by CSF were 94.2% respectively. Cases of other neurologic diseases did not show false positive reactions in both samples. 3. When serum was assayed, taeniasis(2/18), sparganosis(2/20), paragonimiasis(1/56), clonorchiasis(1/15) and fascioliasis(1/1) cases showed cross reactions. When CSF was assayed, 2 ot 10 neuro-sparganosis showed cross reactions while none of 9 neuro-paragonimiasis showed it. Out of 71 confirmed neuro-cysticercosis cases, 6 and 11 showed cross reactions by serum and CSF to crude extract antigen of sparganum; but no case did show it to crude extract antigen of Paragonimus westermani. 4. Ventricular CSF showed low or negative levels of IgG antibody than lumbar CSF unless the lesion was at the lateral ventricle itself. 5. Out of 4 racemose cysticercosis cases, 3 showed positive reaction in serum while all of 3 examined CSF were positive. The above results indicated that the serological test for detecting the specific IgG antibody by micro-ELISA using paired samples of serum and CSF was very helpful for clinical differentiation of neuro-cysticercosis from neurologic diseases of other causes.

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A Lateral Flow Immunoassay Kit for Detecting Residues of Four Groups of Antibiotics in Farmed Fish (어류 중 4계열 잔류 항생물질 검출을 위한 Lateral Flow Immunoassay Kit 개발)

  • Jo, Mi Ra;Son, Kwang Tae;Kwon, Ji Young;Mok, Jong Soo;Park, Hong Jae;Kim, Hyun Yong;Kim, Gyung Dong;Kim, Ji Hoe;Lee, Tae Seek
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.48 no.2
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    • pp.158-167
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    • 2015
  • A lateral flow immunoassay kit based on antigen-antibody interactions was developed to detect residues of beta-lactams, quinolones, tetracyclines, and sulfonamides in farmed fish. Group-specific antibodies showing cross-reactivity with other antibiotics in the same group were produced in rabbits. The rabbits were immunized eight times to obtain the maximum titers. Antibodies were extracted from the antisera collected from the immunized rabbits and produced group-specific reactions with antibiotics from the four groups. A kit was prepared that optimize conditions for the antigen-antibody reaction, using colloidal gold conjugated antibodies, and was designed to detect the four groups of antibiotics simultaneously. The kit enabled the detection of antibiotics in the four groups at below maximum residue limits (MRLs), which were $200{\mu}g/kg$ for tetracyclines, $100{\mu}g/kg$ for sulfonamides, $50{\mu}g/kg$ for beta-lactams, and $100{\mu}g/kg$ for quinolones. The cross-reactivity of the antibodies ranged from 10-80% for the sulfonamides, 20-100% for tetracyclines, 38-100% for quinolones, and 20-100% for the beta-lactams, confirming that the antibodies were group specific. The test kit was used 30 times to examine spiked antibiotics at the limits of detection (LODs) and all produced positive results, indicating high sensitivity. The LODs for the assay ranged from 4-20 ng/mL for beta-lactams, 25-50 ng/mL for sulfonamides, 20-100 ng/mL for tetracyclines, and 30-80 ng/mL for quinolones, and there were no false negative reactions at above these LODs. In addition, all of the LODs of the developed kit were correlated with high-performance liquid chromatography (HPLC) data. Our lateral flow immunoassay kit can simultaneously detect antibiotic residues from a large number of fish samples rapidly, strengthening the safety of domestic farmed and imported fish.

Development and Evaluation of Multiplex PCR for the Detection of Carbapenemase-Producing Enterobacteriaceae (카바페넴분해효소 생성 장내세균 검출을 위한 Multiplex PCR의 개발 및 평가)

  • Kim, Si Hyun;Bae, Il Kwon;Kim, Na Young;Song, Sae Am;Kim, Sunjoo;Jeong, Joseph;Shin, Jeong Hwan
    • Annals of Clinical Microbiology
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    • v.22 no.1
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    • pp.9-13
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    • 2019
  • Background: The isolation of carbapenemase-producing Enterobacteriaceae (CPE) has become increasingly common. Continuous surveillance for these organisms is essential because their infections are closely related to outbreaks of illness and are associated with high mortality rates. The aim of this study was to develop and evaluate multiplex PCR as a means of detecting several important CPE genes simultaneously. Methods: We aimed to develop a multiplex PCR that could detect seven CPE genes simultaneously. The multiplex PCR was composed of seven primer sets for the detection of KPC, IMP, VIM, NDM-1, GES, OXA-23, and OXA-48. We designed different PCR product sizes of at least 100 bp. We evaluated the performance of this new test using 69 CPE-positive clinical isolates. Also, we confirmed the specificity to rule out false-positive reactions by using 71 carbapenem-susceptible clinical strains. Results: A total of 69 CPE clinical isolates showed positive results and were correctly identified as KPC (N=14), IMP (N=13), OXA-23 (N=12), OXA-48 (N=11), VIM (N=9), GES (N=5), and NDM (N=5) by the multiplex PCR. All 71 carbapenem-susceptible clinical isolates, including Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa, showed negative results. Conclusion: This multiplex PCR can detect seven CPE genes at a time and will be useful in clinical laboratories.