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Displaying publications 61 - 80 of 96 in total

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Demonstration of an outer membrane protein that is antigenically specific for Acinetobacter baumannii

Islam AH, Singh KK, Ismail A

Diagn Microbiol Infect Dis, 2011 Jan;69(1):38-44.
PMID: 21146712 DOI: 10.1016/j.diagmicrobio.2010.09.008

Acinetobacter baumannii is an emerging nosocomial pathogen that is resistant to many types of antibiotics, and hence, a fast, sensitive, specific, and economical test for its rapid diagnosis is needed. Development of such a test requires a specific antigen, and outer membrane proteins (OMPs) are the prime candidates. The goal of this study was to find a specific OMP of A. baumannii and demonstrate the presence of specific IgM, IgA, and IgG against the candidate protein in human serum. OMPs of A. baumannii ATCC 19606 and 16 other clinical isolates of A. baumannii were extracted from an overnight culture grown at 37 °C. Protein profiles were obtained using sodium dodecyl sulfate polyacrylamide gel electrophoresis, and Western blot analysis was performed to detect the presence of IgM, IgA, and IgG against the OMP in host serum. An antigenic 34.4-kDa OMP was uniquely recognized by IgM, IgA, and IgG from patients with A. baumannii infection, and it did not cross-react with sera from patients with other types of infection. The band was also found in the other 16 A. baumannii isolates. This 34.4-kDa OMP is a prime candidate for development of a diagnostic test for the presence of A. baumannii.

Matched MeSH terms: Immunoassay/methods
Evaluation of the monoclonal stool antigen test for Helicobacter pylori in an Asian population with dyspepsia

Bhewa Y, Hilmi I, Cheah PL, Navaratnam P, Goh KL

J Dig Dis, 2007 Nov;8(4):207-10.
PMID: 17970878

Although well established in the West, stool antigen tests (SAT) are not widely used in Asia. Data on the accuracy of this test in Asia is sparse and, to date, there have been no studies looking at the more refined monoclonal SAT. The aim of this study is to validate the diagnostic accuracy of a stool antigen test, Hp STAR, for the detection of Helicobacter pylori.

Matched MeSH terms: Immunoassay/methods*
Fulltext Combining parasite lactate dehydrogenase-based and histidine-rich protein 2-based rapid tests to improve specificity for diagnosis of malaria Due to Plasmodium knowlesi and other Plasmodium species in Sabah, Malaysia

Grigg MJ, William T, Barber BE, Parameswaran U, Bird E, Piera K, et al.

J Clin Microbiol, 2014 Jun;52(6):2053-60.
PMID: 24696029 DOI: 10.1128/JCM.00181-14

Plasmodium knowlesi causes severe and fatal malaria in Malaysia. Microscopic misdiagnosis is common and may delay appropriate treatment. P. knowlesi can cross-react with "species-specific" parasite lactate dehydrogenase (pLDH) monoclonal antibodies used in rapid diagnostic tests (RDTs) to detect P. falciparum and P. vivax. At one tertiary-care hospital and two district hospitals in Sabah, we prospectively evaluated two combination RDTs for malaria diagnosis by using both a pan-Plasmodium-pLDH (pan-pLDH)/P. falciparum-specific-pLDH (Pf-pLDH) RDT (OptiMAL-IT) and a non-P. falciparum VOM-pLDH/Pf-HRP2 RDT (CareStart). Differential cross-reactivity among these combinations was hypothesized to differentiate P. knowlesi from other Plasmodium monoinfections. Among 323 patients with PCR-confirmed P. knowlesi (n = 193), P. falciparum (n = 93), and P. vivax (n = 37) monoinfections, the VOM-pLDH individual component had the highest sensitivity for nonsevere (35%; 95% confidence interval [CI], 27 to 43%) and severe (92%; CI, 81 to 100%) P. knowlesi malaria. CareStart demonstrated a P. knowlesi sensitivity of 42% (CI, 34 to 49%) and specificity of 74% (CI, 65 to 82%), a P. vivax sensitivity of 83% (CI, 66 to 93%) and specificity of 71% (CI, 65 to 76%), and a P. falciparum sensitivity of 97% (CI, 90 to 99%) and specificity of 99% (CI, 97 to 100%). OptiMAL-IT demonstrated a P. knowlesi sensitivity of 32% (CI, 25 to 39%) and specificity of 21% (CI, 15 to 29%), a P. vivax sensitivity of 60% (CI, 42 to 75%) and specificity of 97% (CI, 94 to 99%), and a P. falciparum sensitivity of 82% (CI, 72 to 89%) and specificity of 39% (CI, 33 to 46%). The combination of CareStart plus OptiMAL-IT for P. knowlesi using predefined criteria gave a sensitivity of 25% (CI, 19 to 32%) and specificity of 97% (CI, 92 to 99%). Combining two RDT combinations was highly specific for P. knowlesi malaria diagnosis; however, sensitivity was poor. The specificity of pLDH RDTs was decreased for P. vivax and P. falciparum because of P. knowlesi cross-reactivity and cautions against their use alone in areas where P. knowlesi malaria is endemic. Sensitive P. knowlesi-specific RDTs and/or alternative molecular diagnostic tools are needed in areas where P. knowlesi malaria is endemic.

Matched MeSH terms: Immunoassay/methods
Evaluation of rapid influenza diagnostic tests for influenza A and B in the tropics

Chong YM, Tan XH, Hooi PS, Lee LM, Sam IC, Chan YF

J Med Virol, 2019 08;91(8):1562-1565.
PMID: 31032971 DOI: 10.1002/jmv.25495

Rapid diagnosis of influenza is important for early treatment and institution of control measures. In developing tropical countries such as Malaysia, influenza occurs all year round, but molecular assays and conventional techniques (such as immunofluorescence and culture) for diagnosis are not widely available. Rapid influenza diagnostic tests (RIDTs) may be useful in this setting. A total of 552 fresh respiratory specimens were assessed from patients with respiratory symptoms at a teaching hospital in Kuala Lumpur, Malaysia from November 2017 to March 2018. Two digital immunoassays (DIAs), STANDARD F Influenza A/B Fluorescence Immunoassay (STANDARD F) and Sofia Influenza A + B Fluorescence Immunoassay (Sofia) and one conventional RIDT (immunochromatographic assay), SD Bioline Influenza Ag A/B/A(H1N1) Pandemic rapid test kit (SD Bioline) were evaluated in comparison with a WHO-recommended reverse transcription quantitative PCR (RT-qPCR). Of the 552 samples, influenza A virus was detected in 47 (8.5%) and influenza B virus in 7 (1.3%). The digital immunoassays STANDARD F and Sofia had significantly higher overall sensitivity rates (71.7% and 70.6%, respectively) than the conventional RIDT SD Bioline and immunofluorescence/viral culture (55.8% and 52.8%, respectively). Sensitivity rates were higher for influenza A than influenza B, and specificity rates were uniformly high, ranging from 98% to 100%. Digital readout RIDTs can be used in tropical settings with year-round influenza if PCR is unavailable.

Matched MeSH terms: Immunoassay/methods*
Fulltext Conventional rapid latex agglutination in estimation of von Willebrand factor: method revisited and potential clinical applications

Mahat M, Abdullah WZ, Hussin CM

J Immunol Res, 2014;2014:850810.
PMID: 25759835 DOI: 10.1155/2014/850810

Measurement of von Willebrand factor antigen (VWF : Ag) levels is usually performed in a specialised laboratory which limits its application in routine clinical practice. So far, no commercial rapid test kit is available for VWF : Ag estimation. This paper discusses the technical aspect of latex agglutination method which was established to suit the purpose of estimating von Willebrand factor (VWF) levels in the plasma sample. The latex agglutination test can be performed qualitatively and semiquantitatively. Reproducibility, stability, linearity, limit of detection, interference, and method comparison studies were conducted to evaluate the performance of this test. Semiquantitative latex agglutination test was strongly correlated with the reference immunoturbidimetric assay (Spearman's rho = 0.946, P < 0.001, n = 132). A substantial agreement (κ = 0.77) was found between qualitative latex agglutination test and the reference assay. Using the scoring system for the rapid latex test, no agglutination is with 0% VWF : Ag (control negative), 1+ reaction is equivalent to <20% VWF : Ag, and 4+ reaction indicates >150% VWF : Ag (when comparing with immunoturbidimetric assay). The findings from evaluation studies suggest that latex agglutination method is suitable to be used as a rapid test kit for the estimation of VWF : Ag levels in various clinical conditions associated with high levels and low levels of VWF : Ag.

Matched MeSH terms: Immunoassay
Extraction, isolation and characterization of bioactive compounds from plants' extracts

Sasidharan S, Chen Y, Saravanan D, Sundram KM, Yoga Latha L

Afr J Tradit Complement Altern Med, 2011;8(1):1-10.
PMID: 22238476

Natural products from medicinal plants, either as pure compounds or as standardized extracts, provide unlimited opportunities for new drug leads because of the unmatched availability of chemical diversity. Due to an increasing demand for chemical diversity in screening programs, seeking therapeutic drugs from natural products, interest particularly in edible plants has grown throughout the world. Botanicals and herbal preparations for medicinal usage contain various types of bioactive compounds. The focus of this paper is on the analytical methodologies, which include the extraction, isolation and characterization of active ingredients in botanicals and herbal preparations. The common problems and key challenges in the extraction, isolation and characterization of active ingredients in botanicals and herbal preparations are discussed. As extraction is the most important step in the analysis of constituents present in botanicals and herbal preparations, the strengths and weaknesses of different extraction techniques are discussed. The analysis of bioactive compounds present in the plant extracts involving the applications of common phytochemical screening assays, chromatographic techniques such as HPLC and, TLC as well as non-chromatographic techniques such as immunoassay and Fourier Transform Infra Red (FTIR) are discussed.

Matched MeSH terms: Immunoassay
Fulltext Total 25-OH vitamin D concentrations in Chinese, Malays and Indians

Hawkins R

Ann Lab Med, 2013 Mar;33(2):156-8.
PMID: 23479565 DOI: 10.3343/alm.2013.33.2.156
Matched MeSH terms: Immunoassay
Fulltext Site-specific scFv labelling with invertase via Sortase A mechanism as a platform for antibody-antigen detection using the personal glucose meter

Ismail NF, Lim TS

Sci Rep, 2016 Jan 19;6:19338.
PMID: 26782912 DOI: 10.1038/srep19338

Antibody labelling to reporter molecules is gaining popularity due to its many potential applications for diagnostics and therapeutics. However, non-directional bioconjugation methods which are commonly used often results in the loss of target binding capabilities. Therefore, a site-specific enzymatic based bioconjugation such as sortase-mediated transpeptidation allows for a more rapid and efficient method of antibody conjugation for diagnostic applications. Here we describe the utilization of sortase A bioconjugation to conjugate a single chain fragment variable (scFv) to the extracellular invertase (invB) from Zymomonas mobilis with the aim of developing an invertase based immunoassay. In addition, conjugation to enhanced green fluorescent protein (eGFP) was also validated to show the flexibility of the method. The invertase conjugated complex was successfully applied for the detection of antibody-antigen interaction using a personal glucose meter (PGM) for assay readout. The setup was used in both a direct and competitive assay highlighting the robustness of the conjugate for assay development. The method provides an alternative conjugation process to allow easy exchange of antibodies to facilitate rapid development of diagnostic assays for various diseases on the PGM platform.

Matched MeSH terms: Immunoassay
Natural rubber latex allergens: new developments

Yeang HY

Curr Opin Allergy Clin Immunol, 2004 Apr;4(2):99-104.
PMID: 15021061

PURPOSE OF REVIEW:
New allergenic latex proteins have been identified, whereas further information on known latex allergens has emerged in recent years. Although prevalence figures for sensitization to the various latex allergens have been published in several studies in the past, the data have not been collated to facilitate cross-comparison.

RECENT FINDINGS:
Salient characteristics of the three most recently identified latex allergens, Hev b 11, 12 and 13 are described, whereas new findings on some of the previously recognized allergens are examined. Hev b 2 is viewed from the standpoint of allergenicity and protein glycosylation, Hev b 4 in relation to its biochemical identity and molecular cloning, Hev b 5 with respect to its recombinant form, and Hev b 6 in connection with conformational IgE epitopes. Reports on sensitization or allergic reaction to purified latex allergens from recent and past work are summarized. The use of latex allergens in latex allergy diagnostics is reviewed and discussed.

SUMMARY:
Thirteen latex allergens have been recognized by the International Union of Immunological Societies. Based on the results of published studies, native Hev b 2, recombinant Hev b 5, native or recombinant Hev b 6, native Hev b 13, and possibly native Hev b 4 are the major allergens relevant to latex-sensitized adults. Although there is an increasing tendency to identify and characterize latex allergens largely on the basis of their recombinant forms, not all such recombinant proteins have been fully validated against their native counterparts with respect to clinical significance.

Matched MeSH terms: Immunoassay
Fulltext Detection of anti-cell membrane DNA antibodies by indirect immunoflouresencence technique in systemic lupus erythematosus

Faten Nurul Amira Awing Kechik, Maha Abdullah, Masriana Hassan, Masita Arip, Hasni Mahayidin

Malaysian Journal of Medicine and Health Sciences, 2019;15(108):28-28.
MyJurnal

Introduction: Systemic lupus erythematosus (SLE) has a broad spectrum of clinical presentations. The diagnosis of SLE remains a challenge and largely depends on the presence of several serum autoantibodies including anti-nuclear antibody (ANA), anti-double-stranded DNA antibody (anti-dsDNA) and anti-Smith antibody (anti-Sm). ANA, a highly sensitive but not specific marker is used for SLE screening Anti-dsDNA and anti-Sm are SLE-specific biomarkers but has lower sensitivity of 80% and 30% for SLE, respectively. However, it is noted that there are SLE patients who are persistently negative for SLE-specific autoantibodies. Anti-dsDNA and anti-Sm were reported to be negative in up to 51.2% and 62.4% of SLE, respectively. This limitation can lead to misdiagnosis and halter proper treatment to SLE patients. Previous studies have suggested that cell membrane DNA (cmDNA) can act as a specific target for the autoantibodies in SLE patients. Autoantibodies towards cmDNA (anti-cmDNA) were reported to have promis-ing value as a reliable biomarker for SLE. In this study, we would like to determine the usefulness of anti-cmDNA in diagnosing SLE as compared to the standard SLE-specific autoantibodies. Methods: Serum samples from 83 SLE patients, 86 other connective tissue diseases and 61 healthy subjects were included in this study. The other connec-tive tissue diseases include samples from 10 Sjogren’s syndrome, 56 rheumatoid arthritis, 12 scleroderma and eight mixed connected tissues disease (MCTD) patients. All samples were analysed by indirect immunofluorescence (IIF) technique using Raji cells as substrate to detect the presence of anti-cmDNA. Anti-cmDNA was reported as positive if there was presence of a fluorescent ring, either continuous or punctate. Sera from SLE patients were also tested for anti-dsDNA and anti-Sm antibodies by using enzyme-immunoassays. Results: Anti-cmDNA positivity was highest in SLE (55.4%) than in other connective tissue diseases (9.3%) and healthy subjects (0%). Anti-cmDNA was 100% spe-cific at differentiating SLE from healthy subjects and 90.7% specific at differentiating SLE from other connective tissue diseases. There was no difference in the sensitivity (55.4%) of anti-cmDNA at differentiating SLE from both groups. Anti-cmDNA were present in 46 SLE samples negative for standard SLE-specific autoantibodies. It was detected in 11 (42.3%) of anti-dsDNA, 23 (63.9%) of anti-Sm and 8 (12.9%) of both anti-Sm and anti-dsDNA negative samples. Conclusion: The high specificity of anti-cmDNA detection using IIF method makes it an excellent diagnostic tool for SLE. Anti-cmDNA is potentially a very useful biomarker for SLE with negative anti-dsDNA or/and anti-Sm antibodies.

Matched MeSH terms: Immunoassay
Nanodiagnostic Attainments and Clinical Perspectives on C-Reactive Protein: Cardiovascular Disease Risks Assessment

Letchumanan I, Arshad MKM, Gopinath SCB

Curr Med Chem, 2021;28(5):986-1002.
PMID: 31971105 DOI: 10.2174/0929867327666200123092648

Cardiovascular disease (CVD) has become one of the leading causes of morbidity and mortality in both men and women. According to the World Health Organization (WHO), ischemic heart disease is the major issue due to the narrowing of the coronary artery by plaque formation on the artery wall, which causes an inadequate flow of oxygen and blood to the heart and is called 'coronary artery disease'. The CVD death rate increased by up to 15% in 2016 (~17.6 million) compared to the past decade. This tremendous increment urges the development of a suitable biomarker for rapid and early diagnosis. Currently, C-reactive protein (CRP) is considered an outstanding biomarker for quick and accurate outcomes in clinical analyses. Various techniques have also been used to diagnose CVD, including surface plasmon resonance (SPR), colorimetric assay, enzyme-linked immunosorbent assay (ELISA), fluoro-immunoassays, chemiluminescent assays, and electrical measurements. This review discusses such diagnostic strategies and how current, cutting-edge technologies have enabled the development of high-performance detection methodologies. Concluding remarks have been made concerning the clinical significance and the use of nanomaterial in medical diagnostics towards nanotheranostics.

Matched MeSH terms: Immunoassay
Fulltext Endocrinopathies in HIV infected patients

Rosdina Zamrud Ahmad Akbar, Sharifah Faradila Wan Muhammad Hatta, Rosnida Mohd Noh, Fatimah Zaherah Mohd Shah, Thuhairah Abdul Rahman, Rohana Abdul Ghani, et al.

Journal of Clinical and Health Sciences, 2020;5(2):39-45.
MyJurnal

Introduction: Hormonal abnormality is one of many clinical manifestations of HIV infections
that is not well understood. However, the consequences could affect quality of life and are
potentially treatable. Thus, this study aimed to determine the prevalence and associated
factors of thyroid, adrenal and gonadal dysfunctions among HIV-infected patients. Methods:
This is a single centre cross-sectional study involving 150 HIV-infected patients attending the
HIV clinic. Each subject was required to answer specific symptoms questionnaire and their
medical records were reviewed for relevant clinical and biochemical data. Blood for was
collected and thyroid hormones, cortisol, ACTH, FSH, LH, testosterone and estradiol were
analysed using electrochemiluminescent immunoassay. Thyroid, adrenal and gonadal axes
abnormalities were identified. Results: Hypogonadism had the highest prevalence amongst
the endocrine abnormalities, which was detected in 23 patients (15.3%), followed by thyroid
dysfunction in 18 patients (12%) and hypocortisolism in 2 patients (1.3%). There was
significant correlation between CD4 count, BMI and age with the hormone levels. Conclusion:
Prevalence of endocrine abnormalities was low in these well-treated HIV-positive patients,
with hypogonadism being the most common. However, significant correlations between CD4
count, age and BMI with the hormonal levels were detected. Clinical symptoms in relation to
endocrinopathy are not specific as a screening tool thus underscoring the need for
biochemical tests to identify these treatable conditions.

Matched MeSH terms: Immunoassay
Combinatorial effects of genistein and sex-steroids on the level of cystic fibrosis transmembrane regulator (CFTR), adenylate cyclase (AC) and cAMP in the cervix of ovariectomised rats

Salleh N, Ismail N, Muniandy S, Korla PK, Giribabu N

Reprod Toxicol, 2015 Dec;58:194-202.
PMID: 26529183 DOI: 10.1016/j.reprotox.2015.10.017

The combinatorial effects of genistein and estrogen (E) or estrogen plus progesterone (E+P) on CFTR, AC and cAMP levels in cervix were investigated. Ovariectomised adult female rats received 50 or 100mg/kg/day genistein with E or E followed by E+P [E+(E+P)] for seven consecutive days. Cervixes were harvested and analyzed for CFTR mRNA levels by Real-time PCR. Distribution of AC and CFTR proteins in endocervix were observed by immunohistochemistry. Levels of cAMP were measured by enzyme-immunoassay. Molecular docking predicted interaction between genistein and AC. Our results indicate that levels of CFTR, AC and cAMP in cervix of rats receiving genistein plus E were higher than E-only treatment (p<0.05) while genistein plus [E+(E+P)] were higher than E+(E+P)-only treatment (p<0.05). In conclusions, increased levels of CFTR, AC and cAMP in cervix of E and E+(E+P)-treated rats by genistein could affect the cervical secretory function which could influence the female reproductive processes.

Matched MeSH terms: Immunoassay
Fulltext Loop-mediated isothermal amplification (LAMP) reaction as viable PCR substitute for diagnostic applications: a comparative analysis study of LAMP, conventional PCR, nested PCR (nPCR) and real-time PCR (qPCR) based on Entamoeba histolytica DNA derived from faecal sample

Foo PC, Nurul Najian AB, Muhamad NA, Ahamad M, Mohamed M, Yean Yean C, et al.

BMC Biotechnol, 2020 Jun 22;20(1):34.
PMID: 32571286 DOI: 10.1186/s12896-020-00629-8

BACKGROUND: This study reports the analytical sensitivity and specificity of a Loop-mediated isothermal amplification (LAMP) and compares its amplification performance with conventional PCR, nested PCR (nPCR) and real-time PCR (qPCR). All the assays demonstrated in this study were developed based on Serine-rich Entamoeba histolytica protein (SREHP) gene as study model.
RESULTS: A set of SREHP gene specific LAMP primers were designed for the specific detection of Entamoeba histolytica. This set of primers recorded 100% specificity when it was evaluated against 3 medically important Entamoeba species and 75 other pathogenic microorganisms. These primers were later modified for conventional PCR, nPCR and qPCR applications. Besides, 3 different post-LAMP analyses including agarose gel electrophoresis, nucleic acid lateral flow immunoassay and calcein-manganese dye techniques were used to compare their limit of detection (LoD). One E. histolytica trophozoite was recorded as the LoD for all the 3 post-LAMP analysis methods when tested with E. histolytica DNA extracted from spiked stool samples. In contrast, none of the PCR method outperformed LAMP as both qPCR and nPCR recorded LoD of 100 trophozoites while the LoD of conventional PCR was 1000 trophozoites.
CONCLUSIONS: The analytical sensitivity comparison among the conventional PCR, nPCR, qPCR and LAMP reveals that the LAMP outperformed the others in terms of LoD and amplification time. Hence, LAMP is a relevant alternative DNA-based amplification platform for sensitive and specific detection of pathogens.

Matched MeSH terms: Immunoassay
A graphene-based dengue immunosensor using plant-derived envelope glycoprotein domain III (EDIII) as the novel probe antigen

Siew QY, Tan SH, Pang EL, Loh HS, Tan MTT

Analyst, 2021 Mar 21;146(6):2009-2018.
PMID: 33523052 DOI: 10.1039/d0an02219e

The envelope glycoprotein domain III (EDIII) of dengue virus (DENV) has been recognised as the antigenic region responsible for receptor binding. In the present work, we have proposed a novel immunosensor constructed on a graphene-coated screen-printed carbon electrode (SPCE) using plant-derived EDIII as the probe antigen to target DENV IgG antibodies. The developed immunosensor demonstrated high sensitivity towards DENV IgG within a wide linear working range (125-2000 ng mL-1) under the optimised sensing conditions. The limit of detection was determined to be 22.5 ng mL-1. The immunosensor also showed high specificity towards DENV IgG, capable of differentiating DENV IgG from the antibodies of other infectious diseases including the similarly structured Zika virus (ZIKV). The ability of the immunosensor to detect dengue antibodies in serum samples was also verified by conducting tests on mouse serum samples. The proposed immunosensor was able to provide a binary (positive/negative) response towards the serum samples comparable to the conventional enzyme-linked immunosorbent assay (ELISA), indicating promising potential for realistic applications.

Matched MeSH terms: Immunoassay
A simple adherence test for detection of IgM antibodies in typhoid

Ong LY, Pang T, Lim SH, Tan EL, Puthucheary SD

J Med Microbiol, 1989 Jul;29(3):195-8.
PMID: 2473209

A simple adherence test to detect IgM antibodies in patients with typhoid is described. The test utilises the IgM-"capture" approach, in which the test serum is applied to microtitration plate wells previously coated with anti-human IgM, followed by application of a stained Salmonella typhi antigen suspension which shows adherence in positive cases. By this test, 58 (95%) of 61 sera from confirmed cases of typhoid possessed IgM antibodies to the H or O or both antigens of S. typhi. In patients for whom a diagnosis of typhoid was based only on a significant Widal-test titre, 31 (41%) of 76 sera had IgM antibodies to the H or O or both antigens of S. typhi. Some cross-reactivity of the IgM antibodies was detected, especially with the O antigens of S. paratyphi A and B. A total of 82 sera from non-typhoidal fevers (leptospirosis, typhus, dengue fever) showed no reactivity in this test. In normal sera there was no detectable IgM to the O antigen of S. typhi and only a small number (3.9%) had low levels of IgM to the H antigen. The significance and potential importance of this simple, sensitive, specific and economical test is discussed.

Matched MeSH terms: Immunoassay
Electroimmunodetection of cardiac C-reactive protein for determining myocardial Injury

Gan X, Gong T, Zheng Y, Gopinath SCB, Zhao K

Biotechnol Appl Biochem, 2021 Apr;68(2):272-278.
PMID: 32275089 DOI: 10.1002/bab.1921

C-reactive protein (CRP) is an acute phase reactant to be a marker of inflammation and has been correlated with the cardiac injury. An immunoassay was performed using anti-human CRP antibody on an InterDigitated electrode (IDE) sensor to determine and specify CRP concentration for diagnosing the condition of myocardial inflammation. To promote the detection, gold nanoparticle (GNP) was seeded on the aminated-IDE surface. Anti-CRP was hitched on the GNP-seeded surface and identified the abundance of CRP. The limit of quantification was found as 100 fM, and the higher current response was noticed by increasing CRP concentrations with the sensitivity at 1 pM. Furthermore, CRP-spiked human serum did not interfere the determination of CRP and increased the current response, indicating suitability for a real-life sample. Similarly, the control experiments with nonimmune antibody Troponin I are not showing the definite current responses, proving the selective identification of CRP. This method of diagnosing is needful to determine the cardiovascular injury at the right time.

Matched MeSH terms: Immunoassay
Development of a thermostabilised triplex LAMP assay with dry-reagent four target lateral flow dipstick for detection of Entamoeba histolytica and non-pathogenic Entamoeba spp

Foo PC, Chan YY, Mohamed M, Wong WK, Nurul Najian AB, Lim BH

Anal Chim Acta, 2017 May 08;966:71-80.
PMID: 28372729 DOI: 10.1016/j.aca.2017.02.019

This study highlighted the development of a four target nitrocellulose-based nucleic acid lateral flow immunoassay biosensor in a dry-reagent strip format for interpretation of double-labelled double-stranded amplicons from thermostabilised triplex loop-mediated isothermal amplification assay. The DNA biosensor contained two test lines which captured biotin and texas red labelled amplicons; a LAMP internal amplification control line that captured digoxigenin labelled amplicon; and a chromatography control line that validated the functionality of the conjugated gold nanoparticles and membrane. The red lines on detection pad were generated when the gold nanoparticles conjugated antibody bound to the fluorescein labelled amplicons, and the capture agents bound to their specific hapten on the other 5' end of the double-stranded amplicon. The applicability of this DNA biosensor was demonstrated using amoebiasis-causing Entamoeba histolytica simultaneously with the non-pathogenic but morphologically identical Entamoeba dispar and Entamoeba moshkovskii. The biosensor detection limit was 10 E. histolytica trophozoites, and revealed 100% specificity when it was evaluated against 3 medically important Entamoeba species and 75 other pathogenic microorganisms. Heat stability test showed that the biosensor was stable for at least 181 days at ambient temperature. This ready-to-use and cold-chain-free biosensor facilitated the post-LAMP analysis based on visualisation of lines on strip instead of observation of amplicon patterns in agarose gel.

Matched MeSH terms: Immunoassay
Clinical judgement perplexed by initially undisclosed use of herbal medicine and unexpected cross-reactivity of immunoassay

Liu KT, Lee CW

Malays J Pathol, 2017 Aug;39(2):189-192.
PMID: 28866703

We report a case of symptomatic bradycardia caused by consumption of a Chinese herbal medicine which was initially undisclosed to the attending emergency physician. The scientific name of the herb is Panax japonicus. Electrocardiogram revealed sinus bradycardia. Laboratory tests were normal except for the detection of a high serum digoxin level. Further interrogation of the patient eventually disclosed ingestion of the herb which, however, did not contain any digoxin. Other active ingredients in the herb include various types of ginsenoside. These are digoxin-like substances that had caused the observed false-positive detection of digoxin by fluorescence polarization immunoassay due to cross-reactivity. Our case-report provides an important insight about a blind-spot in the field of laboratory medicine (clinical pathology), namely, the false positive detection of digoxin due to crossreactivity in the immunoassay when we come across digoxin-like substances in clinical scenarios, which has barely received attention in the medical literature. It also conveys a clear educational message that with full understanding of the laboratory methodology and its mechanistic rationale there are actually some tricks-of-the-trade that allow us to optimize the specificity of the biochemical tests and the treatment of digoxin-like substances overdose.

Matched MeSH terms: Immunoassay
Fulltext Knowledge, Attitude and Practice Related to Vitamin D and Its Relationship with Vitamin D Status among Malay Female Office Workers

Jamil NA, Shahudin NN, Abdul Aziz NS, Jia Qi C, Wan Aminuddin WAA, Mat Ludin AF, et al.

Int J Environ Res Public Health, 2019 11 27;16(23).
PMID: 31783521 DOI: 10.3390/ijerph16234735

This study assessed knowledge, attitude and practice (KAP) related to vitamin D and its relationship with vitamin D status among Malay female office workers. A total of 147 women aged between 20 and 55 years were recruited from a university in Kuala Lumpur. They answered questionnaires related to KAP on vitamin D, sun exposure, dietary vitamin D intake and physical activity. Serum 25-hydroxyvitamin D (25OHD) was analysed using an enzyme-linked immunoassay. Nearly half (45%) of the subjects had good knowledge but moderate attitude (76%) and practice (84%) towards sunlight exposure and dietary vitamin D intake. Median serum 25OHD was 34.1 nmol/L with the majority (91%) had vitamin D insufficiency (25OHD < 50 nmol/L). Knowledge was weakly associated with attitude (r = 0.29, p < 0.001) but no association was found between knowledge and practice (r = 0.08, p = 0.355) nor attitude and practice (r = -0.001, p = 0.994). Serum 25OHD was positively associated with sunlight exposure (r = 0.22, p = 0.008) and dietary vitamin D intake (r = 0.37, p < 0.001). It can be implied that this group is at increased risk of low bone health status, which highlights the needs of public health campaigns to improve their vitamin D status.

Matched MeSH terms: Immunoassay

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