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7,596
result(s) for
"diagnostic assay"
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VLP-based indirect ELISA enables reliable sero-diagnosis and epidemiological monitoring of duck circovirus
by
Guo, Fangchao
,
Zhong, Zhaozhen
,
Zhao, Lingyan
in
diagnostic assay
,
duck circovirus
,
epidemiology
2026
Duck circovirus (DuCV) is an emerging immunosuppressive virus that causes growth retardation, feather loss, and increased susceptibility to secondary infections in ducks, leading to significant economic losses in the duck industry. However, existing serological assays for DuCV detection often lack accuracy and reproducibility due to antigen instability, limiting effective disease surveillance.
To develop a more reliable diagnostic tool, the full-length capsid (Cap) gene of DuCV-2 was codon-optimized, expressed in
, purified under denaturing conditions, and refolded to self-assemble into virus-like particles (VLPs). The morphology of the assembled VLPs (~15 nm) was confirmed by transmission electron microscopy, and their immunogenicity was evaluated in ducks. Based on these VLPs, an indirect enzyme-linked immunosorbent assay (iELISA) was established and optimized.
The VLPs elicited stronger antibody responses than Cap monomers at equivalent doses, confirming their superior antigenicity. The optimized VLP-based iELISA (250 ng/well coating concentration, 1,200 serum dilution) exhibited high sensitivity (detectable up to 1:6400 dilution), strong specificity (no cross-reactivity with other avian pathogens), and good repeatability (CV < 5%). Application of the assay to 290 field duck sera collected in Jiangsu Province (2022-2024) revealed a 19.96% positivity rate, showing a gradual yearly increase.
This study developed a highly specific, sensitive, and reproducible VLP-based iELISA for DuCV antibody detection. The method provides a practical tool for large-scale epidemiological surveillance and vaccine evaluation, and the VLP-based diagnostic strategy offers a universal framework for serological assays of other avian circoviruses.
Journal Article
Trends and Predictors of Syphilis Prevalence in the General Population: Global Pooled Analyses of 1103 Prevalence Measures Including 136 Million Syphilis Tests
by
Smolak, Alex
,
Kassebaum, Nicholas J
,
Chico, R Matthew
in
Adult
,
and Commentaries
,
Databases, Factual
2018
This study assessed levels, trends, and associations of observed syphilis prevalence in the general adult population using global pooled analyses.
A standardized database of syphilis prevalence was compiled by pooling systematically gathered data. Random-effects meta-analyses and meta-regressions were conducted using data from the period 1990-2016 to estimate pooled measures and assess predictors and trends. Countries were classified by World Health Organization region. Sensitivity analyses were conducted.
The database included 1103 prevalence measures from 136 million syphilis tests across 154 countries (85% from women in antenatal care). Global pooled mean prevalence (weighted by region population size) was 1.11% (95% confidence interval [CI], .99-1.22). Prevalence predictors were region, diagnostic assay, sample size, and calendar year interacting with region. Compared to the African Region, the adjusted odds ratio (AOR) was 0.42 (95% CI, .33-.54) for the Region of the Americas, 0.13 (95% CI, .09-.19) for the Eastern Mediterranean Region, 0.05 (95% CI, .03-.07) for the European Region, 0.21 (95% CI, .16-.28) for the South-East Asia Region, and 0.41 (95% CI, .32-.53) for the Western Pacific Region. Treponema pallidum hemagglutination assay (TPHA) only or rapid plasma reagin (RPR) only, compared with dual RPR/TPHA diagnosis, produced higher prevalence (AOR >1.26), as did smaller sample-size studies (<500 persons) (AOR >2.16). Prevalence declined in all regions; the annual AORs ranged from 0.84 (95% CI, .79-.90) in the Eastern Mediterranean to 0.97 (95% CI, .97-1.01) in the Western Pacific. The pooled mean male-to-female prevalence ratio was 1.00 (95% CI, .89-1.13). Sensitivity analyses confirmed robustness of results.
Syphilis prevalence has declined globally over the past 3 decades. Large differences in prevalence persist among regions, with the African Region consistently the most affected.
Journal Article
Correction: New diagnostic assays for differential diagnosis between the two distinct lineages of bovine influenza D viruses and human influenza C viruses
by
Sakr, Ahmed
,
Okda, Faten A.
,
Nelson, Eric
in
blocking ELISA
,
diagnostic assay
,
differential diagnosis
2025
[This corrects the article DOI: 10.3389/fvets.2020.605704.].
Journal Article
Evaluation of recombinase polymerase amplification for detection of begomoviruses by plant diagnostic clinics
by
Harmon, Carrie L.
,
Londoño, Maria A.
,
Polston, Jane E.
in
Bean golden yellow mosaic virus
,
Begomovirus - enzymology
,
Begomovirus - genetics
2016
Background
Plant viruses in the genus
Begomovirus
, family
Geminiviridae
often cause substantial crop losses. These viruses have been emerging in many locations throughout the tropics and subtropics. Like many plant viruses, they are often not recognized by plant diagnostic clinics due in large part to the lack of rapid and cost effective assays. An isothermal amplification assay, Recombinase polymerase amplification (RPA), was evaluated for its ability to detect three begomoviruses and for its suitability for use in plant diagnostic clinics. Methods for DNA extraction and separation of amplicons from proteins used in the assay were modified and compared to RPA manufacturer’s protocols. The modified RPA assays were compared to PCR assays for sensitivity, use in downstream applications, cost, and speed.
Results
Recombinase polymerase amplification (RPA) assays for the detection of
Bean golden yellow mosaic virus
,
Tomato mottle virus
and
Tomato yellow leaf curl virus
(TYLCV) were specific, only amplifying the target viruses in three different host species. RPA was able to detect the target virus when the template was in a crude extract generated using a simple inexpensive extraction method, while PCR was not. Separation of RPA-generated amplicons from DNA-binding proteins could be accomplished by several methods, all of which were faster and less expensive than that recommended by the manufacturer. Use of these modifications resulted in an RPA assay that was faster than PCR but with a similar reagent cost. This modified RPA was the more cost effective assay when labor is added to the cost since RPA can be performed much faster than PCR. RPA had a sensitivity approximate to that of ELISA when crude extract was used as template. RPA-generated amplicons could be used in downstream applications (TA cloning, digestion with a restriction endonuclease, direct sequencing) similar to PCR but unlike some other isothermal reactions.
Conclusions
RPA could prove useful for the cost effective detection of plant viruses by plant diagnostic clinics. It can be performed in one hour or less with a reagent cost similar to that of PCR but with a lower labor cost, and with an acceptable level of sensitivity and specificity.
Journal Article
C-Reactive Protein: Pathophysiology, Diagnosis, False Test Results and a Novel Diagnostic Algorithm for Clinicians
2023
The current literature provides a body of evidence on C-Reactive Protein (CRP) and its potential role in inflammation. However, most pieces of evidence are sparse and controversial. This critical state-of-the-art monography provides all the crucial data on the potential biochemical properties of the protein, along with further evidence on its potential pathobiology, both for its pentameric and monomeric forms, including information for its ligands as well as the possible function of autoantibodies against the protein. Furthermore, the current evidence on its potential utility as a biomarker of various diseases is presented, of all cardiovascular, respiratory, hepatobiliary, gastrointestinal, pancreatic, renal, gynecological, andrological, dental, oral, otorhinolaryngological, ophthalmological, dermatological, musculoskeletal, neurological, mental, splenic, thyroid conditions, as well as infections, autoimmune-supposed conditions and neoplasms, including other possible factors that have been linked with elevated concentrations of that protein. Moreover, data on molecular diagnostics on CRP are discussed, and possible etiologies of false test results are highlighted. Additionally, this review evaluates all current pieces of evidence on CRP and systemic inflammation, and highlights future goals. Finally, a novel diagnostic algorithm to carefully assess the CRP level for a precise diagnosis of a medical condition is illustrated.
Journal Article
Recombinant 3AB3 nonstructural protein-based indirect ELISA for detection of foot-and-mouth disease virus infection-elicited antibodies in goat
2024
Foot-and-mouth disease (FMD) is one of the most important animal diseases of economic significance globally. It is a highly infectious and contagious disease of cloven-hoofed animals including sheep and goat. For sero-diagnosis of FMD, recombinant antigen-based assays are considered as alternatives to conventional approaches such as the liquid phase blocking ELISA (LPBE). The early interventions towards control measures cannot be implemented unless the disease gets promptly diagnosed. It is relatively difficult to clinically diagnose FMD in goat due to the usual milder form or unapparent nature of symptoms. Under such situations where clinical samples are not available, demonstration of infection-specific FMD virus (FMDV) antibodies in serum sample may help identifying the animals exposed to the virus in retrospect. Antibody to 3AB nonstructural protein (NSP) has been considered to be the most reliable indicator for FMD diagnosis. The current study extended the earlier designed recombinant 3AB3 protein-based indirect ELISA originally validated on bovine serum samples to testing serum samples of goat. The performance of the indirect ELISA was validated using internationally accepted PrioCHECK® FMDV NS kit. The overall diagnostic sensitivity (DSn) of the indirect ELISA was estimated to be 95.52% (619/648), while the diagnostic specificity (DSp) on naïve and vaccinated animals varied at 98.06% (557/568) and 94.15% (435/462), respectively. In India, where FMD is prevalent and the goat population is so high, this ‘in-house’ optimized assay can be considered to be an adjunct in sero-epidemiological investigation of FMD in goat.
Journal Article
A DAMP-Based Assay for Rapid and Affordable Diagnosis of Bacterial Meningitis Agents: Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae
by
Mohamed, Al-Abbass
,
Koshel, Elena I.
,
Ateiah, Muhannad
in
Acids
,
Bacterial pneumonia
,
Cerebrospinal fluid
2024
The rapid and accurate diagnosis of meningitis is critical for preventing severe complications and fatalities. This study addresses the need for accessible diagnostics in the absence of specialized equipment by developing a novel diagnostic assay. The assay utilizes dual-priming isothermal amplification (DAMP) with unique internal primers to significantly reduce non-specificity. For fluorescence detection, the dye was selected among Brilliant Green, Thioflavin T, and dsGreen. Brilliant Green is preferred for this assay due to its availability, high fluorescence level, and optimal sample-to-background (S/B) ratio. The assay was developed for the detection of the primary causative agents of meningitis (Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae), and tested on clinical samples. The developed method demonstrated high specificity, no false positives, sensitivity comparable to that of loop-mediated isothermal amplification (LAMP), and a high S/B ratio. This versatile assay can be utilized as a standalone test or an integrated assay into point-of-care systems for rapid and reliable pathogen detection.
Journal Article
Detection and differentiation of low virulence and virulent Orthoavulavirus javaense using a molecular beacon with RT-LAMP
by
Mears, Megan C.
,
Williams-Coplin, Dawn
,
Olivier, Timothy L.
in
631/1647/2017/2003
,
631/326/596
,
Animals
2024
Newcastle disease (ND), an economically important disease in poultry, is caused by virulent strains of the genetically diverse
Orthoavulavirus javaense
(OAVJ). Laboratories rely on quantitative real-time reverse transcription PCR (qRT-PCR) to detect OAVJ and differentiate between OAVJ pathotypes. This study demonstrates that a fusion cleavage site based molecular beacon with reverse transcription loop mediated isothermal amplification (MB-RT-LAMP) assay can detect and differentiate OAVJ pathotypes in a single assay. Data show that the assay can rapidly identify diverse OAVJ genotypes with sensitivity only one log-fold lower than the current fusion qRT-PCR assay (10
4
copies), exhibits a high degree of specificity for OAVJ, and the molecular beacon can differentiate mesogenic/velogenic sequences from lentogenic sequences. Further, data show that a two-minute rapid lysis protocol preceding MB-RT-LAMP can detect and differentiate OAVJ RNA from both spiked samples and oropharyngeal swabs without the need for RNA isolation. As the MB-RT-LAMP assay can rapidly detect and discriminate between lentogenic and mesogenic/velogenic sequences of OAVJ within one assay, without the need for RNA isolation, and is adaptable to existing veterinary diagnostic laboratory workflow without additional equipment, this assay could be a rapid primary screening tool before qRT-PCR based validation in resource limited settings.
Journal Article
Immune checkpoint inhibitors of PD-L1 as cancer therapeutics
2019
Since the discovery of immune checkpoint proteins, there has been a special interest in developing antibodies that block programmed cell death 1 receptor (PD-1) and programmed cell death receptor ligand 1 (PD-L1) for a subset of cancer patients. PD-1 signaling negatively regulates T cell-mediated immune responses and serves as a mechanism for tumors to evade an antigen-specific T cell immunologic response. It plays a role in promoting cancer development and progression by enhancing tumor cell survival. With this background, PD-1 signaling represents a valuable therapeutic target for novel and effective cancer immunotherapy. Clinical data shows that blockade of this PD-1 signaling significantly enhance antitumor immunity, produce durable clinical responses, and prolong survival. Currently, there are three FDA-approved PD-L1 inhibitors for various malignancies ranging from non-small cell lung cancer to Merkel cell carcinoma. This review is to summarize many ongoing phase II/III trials of atezolizumab, durvalumab, avelumab, and new PD-L1 inhibitors in clinical developments. In particular, we focus on key trials that paved the pathway to FDA-approved indications for atezolizumab, durvalumab, and avelumab. Despite the popularity and accelerated FDA approval of PD-L1 inhibitors, further considerations into predictive biomarkers, mechanisms of resistance, treatment duration, immune-related toxicities, and PD-L1 expression threshold are needed to optimize anticancer potential in this class of immunotherapy.
Journal Article
Molecular Expression Differences in Specific Blood Mononuclear Cell‐Types Identify Patients With AL Amyloidosis
2025
The diagnosis of AL amyloidosis is often challenging due to its systemic nature and heterogeneous clinical presentation. Current serological biomarkers for diagnosis and monitoring are not optimal. We have considered the possibility that mononuclear cell‐type specific molecular expression can be used to develop blood‐based biomarkers to diagnose and monitor patients with AL amyloidosis. Peripheral blood monocytes and CD4+ T cells from patients with documented AL amyloidosis or myeloma without amyloidosis were assessed by enhanced flow cytometric analysis for expression levels of 20 analytes chosen for the possibility that their expression levels may lead to diagnostic assays and biomarkers. We found definitive expression level differences for brain‐derived neurotrophin factor (BDNF), calmodulin, and phospho‐TBK1 in CD4+ T cells and for phospho‐GSK3β in monocytes. Logistic regression and ROC analysis showed that BDNF in CD4+ T cells and heme oxygenase 1 in monocytes significantly distinguished between patients with myeloma versus patients with AL amyloidosis (AUC = 0.75). Additionally, we discovered remarkable differences in intermolecular associations between the samples from the two patient groups, suggesting the involvement of specific pathogenetic pathways. Our results demonstrate that mononuclear cell‐type specific molecular expression may be useful for developing a diagnostic assay and biomarkers for patients with AL amyloidosis.
Journal Article