Comparison of Hemoglobin A1c assay performance on two different commercial systems

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Jozo Ćorić

2015-04-01

Full Text Available Introduction: Glycated hemoglobin (HbA1c is formed by non-enzymatic binding of glucose to the free amino group of the N-terminal end of the ß-chain of hemoglobin A. HbA1c is representative of the mean blood glucose level over three months. The aim of the study was to evaluate the Hemoglobin A1c immunoturbidimetric assay performance on two different commercial systems.Methods: We evaluated the precision and trueness for determination of HbA1c in whole blood. Concentrations of total hemoglobin and HbA1c were evaluated on Dimension Xpand (Siemens and Cobas 501 (Roche analyzers. HbA1c was measured in a latex agglutination inhibition test. Commercial controls Liquichek Diabetes Control Level 1 and Liquichek Diabetes Control Level 2 (Bio Rad at two levels were used for quality control. Analytical validation of HbA1c included: within-run imprecision, between-day imprecision, inaccuracy and comparison determination on the human samples on 2 systems: Dimension Xpand and Cobas 501 analyzers. Results: Within-run imprecision on the commercially controls for Level 1 is 4.5% and Level 2 is 3.2% between-day imprecision on commercially controls is 6.1% Level 1 and 5.1% Level 2 for respectively inac- curacy on commercially controls for Level 1 is 1.8% and Level 2 is 4.8%. Method comparison on human samples shows the correlation coefficient of 0.99.Conclusion: The presented results of the analytical evaluation methods for the determination of HbA1c showed an acceptable accuracy and precision.

Validation of a KHV antibody enzyme-linked immunosorbent assay (ELISA).

Science.gov (United States)

Bergmann, S M; Wang, Q; Zeng, W; Li, Y; Wang, Y; Matras, M; Reichert, M; Fichtner, D; Lenk, M; Morin, T; Olesen, N J; Skall, H F; Lee, P-Y; Zheng, S; Monaghan, S; Reiche, S; Fuchs, W; Kotler, M; Way, K; Bräuer, G; Böttcher, K; Kappe, A; Kielpinska, J

2017-11-01

Koi herpesvirus (KHV) causes KHV disease (KHVD). The virus is highly contagious in carp or koi and can induce a high mortality. Latency and, in some cases, a lack of signs presents a challenge for virus detection. Appropriate immunological detection methods for anti-KHV antibodies have not yet been fully validated for KHV. Therefore, it was developed and validated an enzyme-linked immunosorbent assay (ELISA) to detect KHV antibodies. The assay was optimized with respect to plates, buffers, antigens and assay conditions. It demonstrated high diagnostic and analytical sensitivity and specificity and was particularly useful at the pond or farm levels. Considering the scale of the carp and koi industry worldwide, this assay represents an important practical tool for the indirect detection of KHV, also in the absence of clinical signs. © 2017 John Wiley & Sons Ltd.

Development and validation of a multiplex add-on assay for sepsis biomarkers using xMAP technology

DEFF Research Database (Denmark)

Kofoed, Kristian; Schneider, Uffe Vest; Scheel, Troels

2006-01-01

BACKGROUND: Sepsis is a common and often fatal disease. Because sepsis can be caused by many different organisms, biomarkers that can aid in diagnosing sepsis and monitoring treatment efficacy are highly warranted. New sepsis markers may provide additional information to complement the currently...... triggering receptor expressed on myeloid cells-1 (sTREM-1), and macrophage migration inhibiting factor (MIF) was developed and validated in-house. This 3-plex assay was added to a commercially available interleukin-1beta (IL-1beta), IL-6, IL-8, granulocyte/macrophage colony-stimulating factor, and tumor...

Development and validation of duplex, triplex, and pentaplex real-time PCR screening assays for the detection of genetically modified organisms in food and feed.

Science.gov (United States)

Huber, Ingrid; Block, Annette; Sebah, Daniela; Debode, Frédéric; Morisset, Dany; Grohmann, Lutz; Berben, Gilbert; Stebih, Dejan; Milavec, Mojca; Zel, Jana; Busch, Ulrich

2013-10-30

Worldwide, qualitative methods based on PCR are most commonly used as screening tools for genetically modified material in food and feed. However, the increasing number and diversity of genetically modified organisms (GMO) require effective methods for simultaneously detecting several genetic elements marking the presence of transgenic events. Herein we describe the development and validation of a pentaplex, as well as complementary triplex and duplex real-time PCR assays, for the detection of the most common screening elements found in commercialized GMOs: P-35S, T-nos, ctp2-cp4-epsps, bar, and pat. The use of these screening assays allows the coverage of many GMO events globally approved for commercialization. Each multiplex real-time PCR assay shows high specificity and sensitivity with an absolute limit of detection below 20 copies for the targeted sequences. We demonstrate by intra- and interlaboratory tests that the assays are robust as well as cost- and time-effective for GMO screening if applied in routine GMO analysis.

Targeted resequencing and variant validation using pxlence PCR assays

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Frauke Coppieters

2016-01-01

Full Text Available The advent of next-generation sequencing technologies had a profound impact on molecular diagnostics. PCR is a popular method for target enrichment of disease gene panels. Using our proprietary primer-design pipeline, primerXL, we have created almost one million assays covering over 98% of the human exome. Here we describe the assay specification and both in silico and wet-lab validation of a selected set of 2294 assays using both next-generation sequencing and Sanger sequencing. Using a universal PCR protocol without optimization, these assays result in high coverage uniformity and limited non-specific coverage. In addition, data indicates a positive correlation between the predictive in silico specificity score and the amount of assay non-specific coverage.

Quality Control Assays for Clinical-Grade Human Mesenchymal Stromal Cells: Validation Strategy.

Science.gov (United States)

Radrizzani, Marina; Soncin, Sabrina; Bolis, Sara; Lo Cicero, Viviana; Andriolo, Gabriella; Turchetto, Lucia

2016-01-01

The present chapter focuses on the validation of the following analytical methods for the control of mesenchymal stromal cells (MSC) for cell therapy clinical trials: Microbiological control for cellular product Endotoxin assay Mycoplasma assay Cell count and viability Immunophenotype Clonogenic potential (CFU-F assay) In our lab, these methods are in use for product release, process control or control of the biological starting materials. They are described in detail in the accompanying Chapter 19.For each method, validation goals and strategy are presented, and a detailed experimental scheme is proposed.

Development and validation of a multiplex add-on assay of biomarkers related to sepsis using xMAP technology

DEFF Research Database (Denmark)

Kofoed, Kristian; Vest Schneider, Uffe; Scheel, Troels

2006-01-01

BACKGROUND: Sepsis is a common and often fatal disease. Because sepsis can be caused by many different organisms, biomarkers that can aid in diagnosing sepsis and monitoring treatment efficacy are highly warranted. New sepsis markers may provide additional information to complement the currently...... triggering receptor expressed on myeloid cells-1 (sTREM-1), and macrophage migration inhibiting factor (MIF) was developed and validated in-house. This 3-plex assay was added to a commercially available interleukin-1beta (IL-1beta), IL-6, IL-8, granulocyte/macrophage colony-stimulating factor, and tumor...

Glucuronoyl Esterase Screening and Characterization Assays Utilizing Commercially Available Benzyl Glucuronic Acid Ester

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Hampus Sunner

2015-09-01

Full Text Available Research on glucuronoyl esterases (GEs has been hampered by the lack of enzyme assays based on easily obtainable substrates. While benzyl d-glucuronic acid ester (BnGlcA is a commercially available substrate that can be used for GE assays, several considerations regarding substrate instability, limited solubility and low apparent affinities should be made. In this work we discuss the factors that are important when using BnGlcA for assaying GE activity and show how these can be applied when designing BnGlcA-based GE assays for different applications: a thin-layer chromatography assay for qualitative activity detection, a coupled-enzyme spectrophotometric assay that can be used for high-throughput screening or general activity determinations and a HPLC-based detection method allowing kinetic determinations. The three-level experimental procedure not merely facilitates routine, fast and simple biochemical characterizations but it can also give rise to the discovery of different GEs through an extensive screening of heterologous Genomic and Metagenomic expression libraries.

Desomorphine Screening Using Commercial Enzyme-Linked Immunosorbent Assays.

Science.gov (United States)

Winborn, Jessica; Kerrigan, Sarah

2017-06-01

Desomorphine ("Krokodil") is a semi-synthetic opioid that has drawn attention as a recreational drug, particularly in Russia, neighboring former Soviet Republics, Eastern and Central Europe. It has no accepted medicinal uses and is currently a schedule I drug in the United States. In clandestine environments, desomorphine is synthesized from codeine using red phosphorous, hydroiodic acid and gasoline. Residual starting materials in illicit preparations have been associated with severe dermatological effects and extensive tissue necrosis. Desomorphine is not well studied, and there are limited reports concerning its pharmacology or detection in biological matrices. Immunoassays are widely relied upon for both antemortem and postmortem toxicology screening. Although desomorphine is an opioid of the phenanthrene-type, its ability to bind to conventional opioid antibodies has not been described. In this report we describe the cross-reactivity of desomorphine using six commercially available enzyme-linked immunosorbent assays (Immunalysis Opiates Direct ELISA, Immunalysis Oxycodone/Oxymorphone Direct ELISA, Randox Opiate ELISA, OraSure Technologies OTI Opiate Micro-plate EIA, Neogen Opiate Group ELISA and Neogen Oxycodone/Oxymorphone ELISA). Cross-reactivites were highly variable between assays, ranging from 77 to desomorphine than those directed towards oxycodone. The Immunalysis Opiates Direct ELISA produced the greatest cross-reactivity, although several of the assays evaluated produced cross-reactivity of a sufficient magnitude to be effective for desomorphine screening. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Validation of a newly developed hexaplex real-time PCR assay for screening for presence of GMOs in food, feed and seed.

Science.gov (United States)

Bahrdt, C; Krech, A B; Wurz, A; Wulff, D

2010-03-01

For years, an increasing number and diversity of genetically modified plants has been grown on a commercial scale. The need for detection and identification of these genetically modified organisms (GMOs) calls for broad and at the same time flexible high throughput testing methods. Here we describe the development and validation of a hexaplex real-time polymerase chain reaction (PCR) screening assay covering more than 100 approved GMOs containing at least one of the GMO targets of the assay. The assay comprises detection systems for Cauliflower Mosaic Virus 35S promoter, Agrobacterium tumefaciens NOS terminator, Figwort Mosaic Virus 34S promoter and two construct-specific sequences present in novel genetically modified soybean and maize that lack common screening elements. Additionally a detection system for an internal positive control (IPC) indicating the presence or absence of PCR inhibiting substances was included. The six real-time PCR systems were allocated to five detection channels showing no significant crosstalk between the detection channels. As part of an extensive validation, a limit of detection (LOD(abs)) GMOs in processed and unprocessed food, feed and seed samples with high efficiency.

Improving validation methods for molecular diagnostics: application of Bland-Altman, Deming and simple linear regression analyses in assay comparison and evaluation for next-generation sequencing.

Science.gov (United States)

Misyura, Maksym; Sukhai, Mahadeo A; Kulasignam, Vathany; Zhang, Tong; Kamel-Reid, Suzanne; Stockley, Tracy L

2018-02-01

A standard approach in test evaluation is to compare results of the assay in validation to results from previously validated methods. For quantitative molecular diagnostic assays, comparison of test values is often performed using simple linear regression and the coefficient of determination (R 2 ), using R 2 as the primary metric of assay agreement. However, the use of R 2 alone does not adequately quantify constant or proportional errors required for optimal test evaluation. More extensive statistical approaches, such as Bland-Altman and expanded interpretation of linear regression methods, can be used to more thoroughly compare data from quantitative molecular assays. We present the application of Bland-Altman and linear regression statistical methods to evaluate quantitative outputs from next-generation sequencing assays (NGS). NGS-derived data sets from assay validation experiments were used to demonstrate the utility of the statistical methods. Both Bland-Altman and linear regression were able to detect the presence and magnitude of constant and proportional error in quantitative values of NGS data. Deming linear regression was used in the context of assay comparison studies, while simple linear regression was used to analyse serial dilution data. Bland-Altman statistical approach was also adapted to quantify assay accuracy, including constant and proportional errors, and precision where theoretical and empirical values were known. The complementary application of the statistical methods described in this manuscript enables more extensive evaluation of performance characteristics of quantitative molecular assays, prior to implementation in the clinical molecular laboratory. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Validation of honey-bee smelling profile by using a commercial electronic nose

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Ana R. Correa

2017-09-01

Full Text Available Honey is a natural sweetener and its quality labels are associated to its botanical or geographical origin, which is being established by palynological and sensorial analysis. The use of fast and non-invasive techniques such as an electronic nose can become an alternative for honey classification. In this study, the operational parameters of a commercial electronic nose were validated to determine the honey odor profile. A central composite design with five factors, three levels and 28 assays was used, varying sample amounts (1, 2 and 3 g, incubation temperature (30, 40 and 50 °C, incubation time 30 min, gas flow (50, 150 and 250 mL/min and injection time (100, 200 and 300 s. The commercial nose had ten sensors. Repeatability was evaluated with a coefficient of variation of 10 %. The response surface methodology was used and the optimal operating conditions were: 3 g of sample, incubation at 50 °C for 17 min, gas flow of 100 mL/min and sampling time of 150 s. Finally, these parameters were used to analyze 19 samples of honey, which were classified according to their odor profiles, showing that it can be a useful tool to classify honey.

Assay Validation For Quantitation of Sn 2+ In Radiopharmaceutical Kits

International Nuclear Information System (INIS)

Muthalib, A; Ramli, Martalena; Herlina; Sarmini, Endang; Suharmadi; Besari, Canti

1998-01-01

An assay validation for quantitation of Sn2+ in radiopharmaceutical kits based on indirect iodometric titration is described. The method is based on the oxidation of sn2+ using a known excess of iodine and the excess unreacted iodine titrated with thiosulphate. Typical analytical parameters considered in this assay validation are precision, accuracy, selectivity or specificity, range, and linearity. The precision of the analytical method is quit good represented by coefficient of variance in range of 1.0% to 6.9 %, for 10 runs of analysis except one analysis shows the coefficient of 10.2 %. The method has an accuracy of 95.6 % - 99 % as percent recoveries at theoretical Sn2+ amounts of 463 μg to 2318μg

Validation of an in vitro contractility assay using canine ventricular myocytes

Energy Technology Data Exchange (ETDEWEB)

Harmer, A.R., E-mail: alex.harmer@astrazeneca.com; Abi-Gerges, N.; Morton, M.J.; Pullen, G.F.; Valentin, J.P.; Pollard, C.E.

2012-04-15

Measurement of cardiac contractility is a logical part of pre-clinical safety assessment in a drug discovery project, particularly if a risk has been identified or is suspected based on the primary- or non-target pharmacology. However, there are limited validated assays available that can be used to screen several compounds in order to identify and eliminate inotropic liability from a chemical series. We have therefore sought to develop an in vitro model with sufficient throughput for this purpose. Dog ventricular myocytes were isolated using a collagenase perfusion technique and placed in a perfused recording chamber on the stage of a microscope at ∼ 36 °C. Myocytes were stimulated to contract at a pacing frequency of 1 Hz and a digital, cell geometry measurement system (IonOptix™) was used to measure sarcomere shortening in single myocytes. After perfusion with vehicle (0.1% DMSO), concentration–effect curves were constructed for each compound in 4–30 myocytes taken from 1 or 2 dog hearts. The validation test-set was 22 negative and 8 positive inotropes, and 21 inactive compounds, as defined by their effect in dog, cynolomolgous monkey or humans. By comparing the outcome of the assay to the known in vivo contractility effects, the assay sensitivity was 81%, specificity was 75%, and accuracy was 78%. With a throughput of 6–8 compounds/week from 1 cell isolation, this assay may be of value to drug discovery projects to screen for direct contractility effects and, if a hazard is identified, help identify inactive compounds. -- Highlights: ► Cardiac contractility is an important physiological function of the heart. ► Assessment of contractility is a logical part of pre-clinical drug safety testing. ► There are limited validated assays that predict effects of compounds on contractility. ► Using dog myocytes, we have developed an in vitro cardiac contractility assay. ► The assay predicted the in vivo contractility with a good level of accuracy.

Cross-validation of commercial enzyme-linked immunosorbent assay and radioimmunoassay for porcine C-peptide concentration measurements in non-human primate serum.

Science.gov (United States)

Gresch, Sarah C; Mutch, Lucas A; Janecek, Jody L; Hegstad-Davies, Rebecca L; Graham, Melanie L

2017-09-01

C-peptide concentration is widely used as a marker of insulin secretion and is especially relevant in evaluating islet graft function following transplantation, because its measurement is not confounded by the presence of exogenous insulin. To address the shortage of human islet donors, the use of porcine islets has been proposed as a possible solution and the stringent pig-to-non-human primate (NHP) model is often the most relevant for pre-clinical evaluation of the potential for diabetes reversal resulting from an islet xenograft. The Millipore radioimmunoassay (RIA) was exclusively used to measure porcine C-peptide (PCP) until 2013 when the assay was discontinued and subsequently a commercially available enzyme-linked immunosorbent assay (ELISA) from Mercodia has been widely adopted. Both assays have been used in pre-clinical trials evaluating the therapeutic potential of xenograft products in reversing diabetes in the pig-to-NHP model, to interpret data in a comparable way it may be useful to perform a harmonization of C-peptide measurements. We performed a method comparison by determining the PCP concentration in 620 serum samples collected from 20 diabetic cynomolgus macaques transplanted with adult porcine islets. All analyses were performed according to manufacturer instructions. With both assays, we demonstrated an acceptable detection limit, precision, and recovery. Linearity of the ELISA met acceptance criteria at all concentrations tested while linearity of the RIA only met acceptance criteria at five of the eight concentrations tested. The RIA had a detection limit of 0.16 ng/mL, and recovery ranged from 82% to 96% and met linearity acceptance criteria at 0.35 ng/mL and from 0.78 to 2.33 ng/mL. The ELISA had a detection limit of 0.03 ng/mL, and recovery ranged from 81% to 115% and met linearity acceptance criteria from 0.08 to 0.85 ng/mL. Both assays had intra-assay precision assay precision ELISA demonstrated a significant correlation with RIA (R

Validation of the Filovirus Plaque Assay for Use in Preclinical Studies

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Amy C. Shurtleff

2016-04-01

Full Text Available A plaque assay for quantitating filoviruses in virus stocks, prepared viral challenge inocula and samples from research animals has recently been fully characterized and standardized for use across multiple institutions performing Biosafety Level 4 (BSL-4 studies. After standardization studies were completed, Good Laboratory Practices (GLP-compliant plaque assay method validation studies to demonstrate suitability for reliable and reproducible measurement of the Marburg Virus Angola (MARV variant and Ebola Virus Kikwit (EBOV variant commenced at the United States Army Medical Research Institute of Infectious Diseases (USAMRIID. The validation parameters tested included accuracy, precision, linearity, robustness, stability of the virus stocks and system suitability. The MARV and EBOV assays were confirmed to be accurate to ±0.5 log10 PFU/mL. Repeatability precision, intermediate precision and reproducibility precision were sufficient to return viral titers with a coefficient of variation (%CV of ≤30%, deemed acceptable variation for a cell-based bioassay. Intraclass correlation statistical techniques for the evaluation of the assay’s precision when the same plaques were quantitated by two analysts returned values passing the acceptance criteria, indicating high agreement between analysts. The assay was shown to be accurate and specific when run on Nonhuman Primates (NHP serum and plasma samples diluted in plaque assay medium, with negligible matrix effects. Virus stocks demonstrated stability for freeze-thaw cycles typical of normal usage during assay retests. The results demonstrated that the EBOV and MARV plaque assays are accurate, precise and robust for filovirus titration in samples associated with the performance of GLP animal model studies.

Measuring factor IX activity of nonacog beta pegol with commercially available one-stage clotting and chromogenic assay kits: a two-center study.

Science.gov (United States)

Bowyer, A E; Hillarp, A; Ezban, M; Persson, P; Kitchen, S

2016-07-01

Essentials Validated assays are required to precisely measure factor IX (FIX) activity in FIX products. N9-GP and two other FIX products were assessed in various coagulation assay systems at two sites. Large variations in FIX activity measurements were observed for N9-GP using some assays. One-stage and chromogenic assays accurately measuring FIX activity for N9-GP were identified. Background Measurement of factor IX activity (FIX:C) with activated partial thromboplastin time-based one-stage clotting assays is associated with a large degree of interlaboratory variation in samples containing glycoPEGylated recombinant FIX (rFIX), i.e. nonacog beta pegol (N9-GP). Validation and qualification of specific assays and conditions are necessary for the accurate assessment of FIX:C in samples containing N9-GP. Objectives To assess the accuracy of various one-stage clotting and chromogenic assays for measuring FIX:C in samples containing N9-GP as compared with samples containing rFIX or plasma-derived FIX (pdFIX) across two laboratory sites. Methods FIX:C, in severe hemophilia B plasma spiked with a range of concentrations (from very low, i.e. 0.03 IU mL(-1) , to high, i.e. 0.90 IU mL(-1) ) of N9-GP, rFIX (BeneFIX), and pdFIX (Mononine), was determined at two laboratory sites with 10 commercially available one-stage clotting assays and two chromogenic FIX:C assays. Assays were performed with a plasma calibrator and different analyzers. Results A high degree of variation in FIX:C measurement was observed for one-stage clotting assays for N9-GP as compared with rFIX or pdFIX. Acceptable N9-GP recovery was observed in the low-concentration to high-concentration samples tested with one-stage clotting assays using SynthAFax or DG Synth, or with chromogenic FIX:C assays. Similar patterns of FIX:C measurement were observed at both laboratory sites, with minor differences probably being attributable to the use of different analyzers. Conclusions These results suggest that, of the

Validation and Application of a Dried Blood Spot Ceftriaxone Assay

Science.gov (United States)

Page-Sharp, Madhu; Nunn, Troy; Salman, Sam; Moore, Brioni R.; Batty, Kevin T.; Davis, Timothy M. E.

2015-01-01

Dried blood spot (DBS) antibiotic assays can facilitate pharmacokinetic/pharmacodynamic (PK/PD) studies in situations where venous blood sampling is logistically and/or ethically problematic. In this study, we aimed to develop, validate, and apply a DBS ceftriaxone assay. A liquid chromatography-tandem mass spectroscopy (LC-MS/MS) DBS ceftriaxone assay was assessed for matrix effects, process efficiency, recovery, variability, and limits of quantification (LOQ) and detection (LOD). The effects of hematocrit, protein binding, red cell partitioning, and chad positioning were evaluated, and thermal stability was assessed. Plasma, DBS, and cell pellet ceftriaxone concentrations in 10 healthy adults were compared, and plasma concentration-time profiles of DBS and plasma ceftriaxone were incorporated into population PK models. The LOQ and LOD for ceftriaxone in DBS were 0.14 mg/liter and 0.05 mg/liter, respectively. Adjusting for hematocrit, red cell partitioning, and relative recovery, DBS-predicted plasma concentrations were comparable to measured plasma concentrations (r > 0.95, P 95% initial concentrations in DBS for 14 h, 35 h, 30 days, 21 weeks, and >11 months, respectively. The present DBS ceftriaxone assay is robust and can be used as a surrogate for plasma concentrations to provide valid PK and PK/PD data in a variety of clinical situations, including in studies of young children and of those in remote or resource-poor settings. PMID:26438505

Validation of a next-generation sequencing assay for clinical molecular oncology.

Science.gov (United States)

Cottrell, Catherine E; Al-Kateb, Hussam; Bredemeyer, Andrew J; Duncavage, Eric J; Spencer, David H; Abel, Haley J; Lockwood, Christina M; Hagemann, Ian S; O'Guin, Stephanie M; Burcea, Lauren C; Sawyer, Christopher S; Oschwald, Dayna M; Stratman, Jennifer L; Sher, Dorie A; Johnson, Mark R; Brown, Justin T; Cliften, Paul F; George, Bijoy; McIntosh, Leslie D; Shrivastava, Savita; Nguyen, Tudung T; Payton, Jacqueline E; Watson, Mark A; Crosby, Seth D; Head, Richard D; Mitra, Robi D; Nagarajan, Rakesh; Kulkarni, Shashikant; Seibert, Karen; Virgin, Herbert W; Milbrandt, Jeffrey; Pfeifer, John D

2014-01-01

Currently, oncology testing includes molecular studies and cytogenetic analysis to detect genetic aberrations of clinical significance. Next-generation sequencing (NGS) allows rapid analysis of multiple genes for clinically actionable somatic variants. The WUCaMP assay uses targeted capture for NGS analysis of 25 cancer-associated genes to detect mutations at actionable loci. We present clinical validation of the assay and a detailed framework for design and validation of similar clinical assays. Deep sequencing of 78 tumor specimens (≥ 1000× average unique coverage across the capture region) achieved high sensitivity for detecting somatic variants at low allele fraction (AF). Validation revealed sensitivities and specificities of 100% for detection of single-nucleotide variants (SNVs) within coding regions, compared with SNP array sequence data (95% CI = 83.4-100.0 for sensitivity and 94.2-100.0 for specificity) or whole-genome sequencing (95% CI = 89.1-100.0 for sensitivity and 99.9-100.0 for specificity) of HapMap samples. Sensitivity for detecting variants at an observed 10% AF was 100% (95% CI = 93.2-100.0) in HapMap mixes. Analysis of 15 masked specimens harboring clinically reported variants yielded concordant calls for 13/13 variants at AF of ≥ 15%. The WUCaMP assay is a robust and sensitive method to detect somatic variants of clinical significance in molecular oncology laboratories, with reduced time and cost of genetic analysis allowing for strategic patient management. Copyright © 2014 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

The OECD validation program of the H295R steroidogenesis assay: Phase 3. Final inter-laboratory validation study

DEFF Research Database (Denmark)

Hecker, Markus; Hollert, Henner; Cooper, Ralph

2011-01-01

In response to increasing concerns regarding the potential of chemicals to interact with the endocrine system of humans and wildlife, various national and international programs have been initiated with the aim to develop new guidelines for the screening and testing of these chemicals in vertebra......In response to increasing concerns regarding the potential of chemicals to interact with the endocrine system of humans and wildlife, various national and international programs have been initiated with the aim to develop new guidelines for the screening and testing of these chemicals...... in vertebrates. Here, we report on the validation of an in vitro assay, the H295R steroidogenesis assay, to detect chemicals with the potential to inhibit or induce the production of the sex steroid hormones testosterone (T) and 17β-estradiol (E2) in preparation for the development of an Organization...... for Economic Cooperation and Development (OECD) test guideline.A previously optimized and pre-validated protocol was used to assess the potential of 28 chemicals of diverse structures and properties to validate the H295R steroidogenesis assay. These chemicals are comprised of known endocrine-active chemicals...

Total antioxidants in plasma of hemodialysed patients and healthy controls measured by two commercial assays

OpenAIRE

Ruskovska, Tatjana; Jansen, Eugene

2012-01-01

Introduction: As a result of an increased interest in oxidative stress research, in both basic and clinical studies, numerous commercial test kits became available. The aim of this study was to evaluate the results for total antioxidants measured by two commercial assays in a complex clinical condition such as single hemodialysis session in patients on chronic hemodialysis treatment, in comparison to healthy controls. Methods: The level of plasma total antioxidants was measured by BAP ...

Protein unfolding allows use of commercial antibodies in an apolipoprotein M sandwich ELISA

DEFF Research Database (Denmark)

Bosteen, Markus Høybye; Dahlbäck, Björn; Nielsen, Lars Bo

2015-01-01

that specifically recognizes human apoM in plasma using commercially available reagents. Commercial apoM antibodies were screened for compatibility in a sandwich ELISA-based assay. One optimal pair of antibodies was chosen, and sample preparation, buffers, and incubation times were optimized to generate a simple...... and reproducible method. Validation and comparison to a previously described ELISA for apoM confirmed that the assay displays a high degree of sensitivity, specificity, and precision. Our results show that commercially available antibodies can be used to accurately measure human plasma apoM. This method can...

Assessing the validity of commercial and municipal food environment data sets in Vancouver, Canada.

Science.gov (United States)

Daepp, Madeleine Ig; Black, Jennifer

2017-10-01

The present study assessed systematic bias and the effects of data set error on the validity of food environment measures in two municipal and two commercial secondary data sets. Sensitivity, positive predictive value (PPV) and concordance were calculated by comparing two municipal and two commercial secondary data sets with ground-truthed data collected within 800 m buffers surrounding twenty-six schools. Logistic regression examined associations of sensitivity and PPV with commercial density and neighbourhood socio-economic deprivation. Kendall's τ estimated correlations between density and proximity of food outlets near schools constructed with secondary data sets v. ground-truthed data. Vancouver, Canada. Food retailers located within 800 m of twenty-six schools RESULTS: All data sets scored relatively poorly across validity measures, although, overall, municipal data sets had higher levels of validity than did commercial data sets. Food outlets were more likely to be missing from municipal health inspections lists and commercial data sets in neighbourhoods with higher commercial density. Still, both proximity and density measures constructed from all secondary data sets were highly correlated (Kendall's τ>0·70) with measures constructed from ground-truthed data. Despite relatively low levels of validity in all secondary data sets examined, food environment measures constructed from secondary data sets remained highly correlated with ground-truthed data. Findings suggest that secondary data sets can be used to measure the food environment, although estimates should be treated with caution in areas with high commercial density.

JaCVAM-organized international validation study of the in vivo rodent alkaline comet assay for the detection of genotoxic carcinogens: I. Summary of pre-validation study results.

Science.gov (United States)

Uno, Yoshifumi; Kojima, Hajime; Omori, Takashi; Corvi, Raffaella; Honma, Masamistu; Schechtman, Leonard M; Tice, Raymond R; Burlinson, Brian; Escobar, Patricia A; Kraynak, Andrew R; Nakagawa, Yuzuki; Nakajima, Madoka; Pant, Kamala; Asano, Norihide; Lovell, David; Morita, Takeshi; Ohno, Yasuo; Hayashi, Makoto

2015-07-01

The in vivo rodent alkaline comet assay (comet assay) is used internationally to investigate the in vivo genotoxic potential of test chemicals. This assay, however, has not previously been formally validated. The Japanese Center for the Validation of Alternative Methods (JaCVAM), with the cooperation of the U.S. NTP Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM)/the Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM), the European Centre for the Validation of Alternative Methods (ECVAM), and the Japanese Environmental Mutagen Society/Mammalian Mutagenesis Study Group (JEMS/MMS), organized an international validation study to evaluate the reliability and relevance of the assay for identifying genotoxic carcinogens, using liver and stomach as target organs. The ultimate goal of this validation effort was to establish an Organisation for Economic Co-operation and Development (OECD) test guideline. The purpose of the pre-validation studies (i.e., Phase 1 through 3), conducted in four or five laboratories with extensive comet assay experience, was to optimize the protocol to be used during the definitive validation study. Copyright © 2015 Elsevier B.V. All rights reserved.

Development and Fit-for-Purpose Validation of a Soluble Human Programmed Death-1 Protein Assay.

Science.gov (United States)

Ni, Yan G; Yuan, Xiling; Newitt, John A; Peterson, Jon E; Gleason, Carol R; Haulenbeek, Jonathan; Santockyte, Rasa; Lafont, Virginie; Marsilio, Frank; Neely, Robert J; DeSilva, Binodh; Piccoli, Steven P

2015-07-01

Programmed death-1 (PD-1) protein is a co-inhibitory receptor which negatively regulates immune cell activation and permits tumors to evade normal immune defense. Anti-PD-1 antibodies have been shown to restore immune cell activation and effector function-an exciting breakthrough in cancer immunotherapy. Recent reports have documented a soluble form of PD-1 (sPD-1) in the circulation of normal and disease state individuals. A clinical assay to quantify sPD-1 would contribute to the understanding of sPD-1-function and facilitate the development of anti-PD-1 drugs. Here, we report the development and validation of a sPD-1 protein assay. The assay validation followed the framework for full validation of a biotherapeutic pharmacokinetic assay. A purified recombinant human PD-1 protein was characterized extensively and was identified as the assay reference material which mimics the endogenous analyte in structure and function. The lower limit of quantitation (LLOQ) was determined to be 100 pg/mL, with a dynamic range spanning three logs to 10,000 pg/mL. The intra- and inter-assay imprecision were ≤15%, and the assay bias (percent deviation) was ≤10%. Potential matrix effects were investigated in sera from both normal healthy volunteers and selected cancer patients. Bulk-prepared frozen standards and pre-coated Streptavidin plates were used in the assay to ensure consistency in assay performance over time. This assay appears to specifically measure total sPD-1 protein since the human anti-PD-1 antibody, nivolumab, and the endogenous ligands of PD-1 protein, PDL-1 and PDL-2, do not interfere with the assay.

Detection and quantification of serum or plasma HCV RNA: mini review of commercially available assays.

Science.gov (United States)

Le Guillou-Guillemette, Helene; Lunel-Fabiani, Francoise

2009-01-01

The treatment schedule (combination of compounds, doses, and duration) and the virological follow-up for management of antiviral treatment in patients chronically infected by HCV is now well standardized, but to ensure good monitoring of the treated patients, physicians need rapid, reproducible, and sensitive molecular virological tools with a wide range of detection and quantification of HCV RNA in blood samples. Several assays for detection and/or quantification of HCV RNA are currently commercially available. Here, all these assays are detailed, and a brief description of each step of the assay is provided. They are divided into two categories by method: those based on signal amplification and those based on target amplification. These two categories are then divided into qualitative, quantitative, and quantitative detection assays. The real-time reverse-transcription polymerase chain reaction (RT-PCR)-based assays are the most promising strategy in the HCV virological area.

Comparative Assessment of Anti-HLA Antibodies Using Two Commercially Available Luminex-Based Assays.

Science.gov (United States)

Clerkin, Kevin J; See, Sarah B; Farr, Maryjane A; Restaino, Susan W; Serban, Geo; Latif, Farhana; Li, Lingzhi; Colombo, Paolo C; Vlad, George; Ray, Bryan; Vasilescu, Elena R; Zorn, Emmanuel

2017-11-01

Allospecific anti-HLA antibodies (Abs) are associated with rejection of solid organ grafts. The 2 main kits to detect anti-HLA Ab in patient serum are commercialized by Immucor and One Lambda/ThermoFisher. We sought to compare the performance of both platforms. Background-adjusted mean fluorescence intensity (MFI) values were used from both platforms to compare sera collected from 125 pretransplant and posttransplant heart and lung transplant recipients. Most HLA class I (94.5%) and HLA class II (89%) Abs with moderate to high MFI titer (≥4000) were detected by both assays. A modest correlation was observed between MFI values obtained from the 2 assays for both class I ( r = 0.3, r 2 = 0.09, P < 0.0001) and class II Ab ( r = 0.707, r 2 = 0.5, P < 0.0001). Both assays detected anti-class I and II Ab that the other did not; however, no specific HLA allele was detected preferentially by either of the 2 assays. For a limited number of discrepant sera, dilution resulted in comparable reactivity profiles between the 2 platforms. Immucor and One Lambda/ThermoFisher assays have a similar, albeit nonidentical, ability to detect anti-HLA Ab. Although the correlation between the assays was present, significant variances exist, some of which can be explained by a dilution-sensitive "prozone" effect.

Quantitative comparison of in house irma/ria methods using reagents supplied in bulk with assays based on commercial kits

International Nuclear Information System (INIS)

Sajid, K.M.; Jafri, S.R.A.

1997-01-01

Due to high cost of commercial kit assays, local trials were started to establish low cost immunoassay techniques at MINAR, Multan. First available alternate of commercial kits was the use of matched reagents supplied in bulk by NETRIA through INMOL, Lahore under IAEA assistance. As quality is crucial in RIA estimations this laboratory collected passive quality control data of 50, 51 and 52 in-house assay batches of T3,T4 and TSH to compare with the same number of last Amerlex RIAs(successive lots). A qualitative comparison based on computerized data analysis shows linear correlation between the results of two assay systems with low and acceptable precision in T3 and T4 assays. In TSH assays both systems show high imprecision although Amerlex RIA system is relatively more precise than in-house TSH- IRMA. T3 and T4 assays in both the systems show wide working ranges covering all clinical regions. In TSH, working ranges of both the techniques do not cover all clinical regions. In-house TSH assay excludes below 5.5 mulU/ml, whereas Amerlex excludes levels below 4.5 mulL/ml. This may reduce the clinical efficacy of these tests. Amerlex-M T3 and T4 assays show high negative drift with relatively less between variation, whereas in-house assays show low positive drift with high between batch variation. (author)

Specificity and sensitivity of commercially available assays for glucagon-like peptide-1 (GLP-1)

DEFF Research Database (Denmark)

Bak, Monika Judyta; Albrechtsen, Nicolai Jacob Wewer; Pedersen, Jens

2014-01-01

assessed with 3 commercial kits. RESULTS: The USCN LIFE assay detected none of the GLP-1 isoforms. The active GLP-1 ELISAs from Millipore and DRG seemed identical and were specific for intact GLP-1 in buffer and plasma. The Meso Scale Discovery Total GLP-1 kit detected all six GLP-1 isoforms, although...

A comparative study in three commercial kits of radioligand assay for GAD-Ab

International Nuclear Information System (INIS)

Yang Yehua; Zhou Zhiguang; Huang Gan; Yang Feike; Li Zhangwei

2006-01-01

Objective: To provide data for perfect selection of glutamic acid decarboxylase antibodies (GAD-Ab) assay commercial kits. Methods: The sera of 88 titer-graded samples by radioligand assay (RLA) were measured with two types of enzyme-linked immunosorbent assay (ELISA) kits and one type of immunoradiometric assay (IRMA) kit for GAD-Ab in order to test their consistency with RLA. Another 140 diabetic sera were measured with RLA and screened by a type of suitable kit to search the cutoff point for discriminating patients who needed rechecking. Results: Compared with RLA, concordance ratio of 3 kits: Medizym kit(75%) > RSR kit(73.9%) > Biomerica kit(62.5%); Kappa value: Medizym kit (0.408, common) > RSR kit (0.405, common) > Biomerica kit (0.185, failing); correlation to RLA index: RSR kit (r= 0.992) > Medizym kit(r= 0. 791 ) > Biomerica kit (r = -0. 055); area under the receiver operating characteristic (ROC) curve: Medizym kit (0.812) > RSR kit (0. 727 ) > Biomerica kit (0.666). Conclusions: The efficiencies of RSR kit and Medizym kit are good. Serum concentration between 0.25-0.99 U/ml measured by RSR kit is suggested to further recheck by RLA. (authors)

Intra-laboratory validation of a human cell based in vitro angiogenesis assay for testing angiogenesis modulators

Directory of Open Access Journals (Sweden)

Jertta-Riina Sarkanen

2011-01-01

Full Text Available The developed standardized human cell based in vitro angiogenesis assay was intra-laboratory validated to verify that the method is reliable and relevant for routine testing of modulators of angiogenesis e.g. pharmaceuticals and industrial chemicals. This assay is based on the earlier published method but it was improved and shown to be more sensitive and rapid than the previous assay. The performance of the assay was assessed by using 6 reference chemicals, which are widely used pharmaceuticals that inhibit angiogenesis: acetyl salicylic acid, erlotinib, 2-methoxyestradiol, levamisole, thalidomide, and anti-vascular endothelial growth factor. In the intra-laboratory validation, the sensitivity of the assay (upper and lower limits of detection and linearity of response in tubule formation, batch to batch variation in tubule formation between different Master cell bank batches, and precision as well as the reliability of the assay (reproducibility and repeatability were tested. The pre-set acceptance criteria for the intra-laboratory validation study were met. The relevance of the assay in man was investigated by comparing the effects of reference chemicals and their concentrations to the published human data. The comparison showed a good concordance, which indicates that this human cell based angiogenesis model predicts well the effects in man and has the potential to be used to supplement and/or replace of animal tests.

Analytical Validation of a Highly Quantitative, Sensitive, Accurate, and Reproducible Assay (HERmark® for the Measurement of HER2 Total Protein and HER2 Homodimers in FFPE Breast Cancer Tumor Specimens

Directory of Open Access Journals (Sweden)

Jeffrey S. Larson

2010-01-01

Full Text Available We report here the results of the analytical validation of assays that measure HER2 total protein (H2T and HER2 homodimer (H2D expression in Formalin Fixed Paraffin Embedded (FFPE breast cancer tumors as well as cell line controls. The assays are based on the VeraTag technology platform and are commercially available through a central CAP-accredited clinical reference laboratory. The accuracy of H2T measurements spans a broad dynamic range (2-3 logs as evaluated by comparison with cross-validating technologies. The measurement of H2T expression demonstrates a sensitivity that is approximately 7–10 times greater than conventional immunohistochemistry (IHC (HercepTest. The HERmark assay is a quantitative assay that sensitively and reproducibly measures continuous H2T and H2D protein expression levels and therefore may have the potential to stratify patients more accurately with respect to response to HER2-targeted therapies than current methods which rely on semiquantitative protein measurements (IHC or on indirect assessments of gene amplification (FISH.

Optimization and validation of a neutralizing antibody assay for HIV-1 in A3R5 cells.

Science.gov (United States)

Sarzotti-Kelsoe, Marcella; Daniell, Xiaoju; Todd, Christopher A; Bilska, Miroslawa; Martelli, Amanda; LaBranche, Celia; Perez, Lautaro G; Ochsenbauer, Christina; Kappes, John C; Rountree, Wes; Denny, Thomas N; Montefiori, David C

2014-07-01

A3R5 is a human CD4(+) lymphoblastoid cell line that was engineered to express CCR5 and is useful for the detection of weak neutralizing antibody responses against tier 2 strains of HIV-1. Here we describe the optimization and validation of the HIV-1 neutralizing antibody assay that utilizes A3R5 cells, performed in compliance with Good Clinical Laboratory Practice (GCLP) guidelines. The assay utilizes Renilla luciferase-expressing replication competent infectious molecular clones (IMC) encoding heterologous env genes from different HIV-1 clades. Key assay validation parameters tested included specificity, accuracy, precision, limit of detection and quantitation, specificity, linearity and range, and robustness. Plasma samples demonstrated higher non-specific activity than serum samples in the A3R5 assay. This assay can tolerate a wide range of virus input but is more sensitive to cell concentration. The higher sensitivity of the A3R5 assay in neutralization responses to tier 2 strains of HIV-1 makes it complementary to, but not a substitute for the TZM-bl assay. The validated A3R5 assay is employed as an endpoint immunogenicity test for vaccine-elicited neutralizing antibodies against tier 2 strains of HIV-1, and to identify correlates of protection in HIV-1 vaccine trials conducted globally. Copyright © 2014 Elsevier B.V. All rights reserved.

Development and validation of receptor occupancy pharmacodynamic assays used in the clinical development of the monoclonal antibody vedolizumab.

Science.gov (United States)

Wyant, Tim; Estevam, Jose; Yang, Lili; Rosario, Maria

2016-03-01

Vedolizumab is a monoclonal antibody approved for use in ulcerative colitis and Crohn's disease. By specifically binding to α4 β7 integrin, vedolizumab prevents trafficking of lymphocytes to the gut, thereby interfering with disease pathology. During the clinical development program, the pharmacodynamic effect of vedolizumab was evaluated by 2 flow cytometry receptor occupancy assays: act-1 (ACT-1) and mucosal addressin cell adhesion molecule-1 (MAdCAM-1). Here we describe the development and validation of these assays. The ACT-1 assay is a receptor occupancy free-site assay that uses a monoclonal antibody with the same binding epitope as vedolizumab to detect free (unbound) sites on α4 β7 integrin. The MAdCAM-1 assay used a soluble version of the natural ligand for α4 β7 integrin to detect free sites. The assays were validated using a fit-for-purpose approach throughout the clinical development of vedolizumab. Both the ACT-1 assay and the MAdCAM-1 assay demonstrated acceptable reproducibility and repeatability. The assays were sufficiently stable to allow for clinical use. During clinical testing the assays demonstrated that vedolizumab was able to saturate peripheral cells at all doses tested. Two pharmacodynamic receptor occupancy assays were developed and validated to assess the effect of vedolizumab on peripheral blood cells. The results of these assays demonstrated the practical use of flow cytometry to examine pharmacodynamic response in clinical trials. © 2015 International Clinical Cytometry Society.

Validation of an immunodiagnostic assay for detection of 13 Streptococcus pneumoniae serotype-specific polysaccharides in human urine.

Science.gov (United States)

Pride, Michael W; Huijts, Susanne M; Wu, Kangjian; Souza, Victor; Passador, Sherry; Tinder, Chunyan; Song, Esther; Elfassy, Arik; McNeil, Lisa; Menton, Ronald; French, Roger; Callahan, Janice; Webber, Chris; Gruber, William C; Bonten, Marc J M; Jansen, Kathrin U

2012-08-01

To improve the clinical diagnosis of pneumococcal infection in bacteremic and nonbacteremic community-acquired pneumonia (CAP), a Luminex technology-based multiplex urinary antigen detection (UAD) diagnostic assay was developed and validated. The UAD assay can simultaneously detect 13 different serotypes of Streptococcus pneumoniae by capturing serotype-specific S. pneumoniae polysaccharides (PnPSs) secreted in human urine. Assay specificity is achieved by capturing the polysaccharides with serotype-specific monoclonal antibodies (MAbs) on spectrally unique microspheres. Positivity for each serotype was based on positivity cutoff values calculated from a standard curve run on each assay plate together with positive- and negative-control urine samples. The assay is highly specific, since significant signals are detected only when each PnPS was paired with its homologous MAb-coated microspheres. Validation experiments demonstrated excellent accuracy and precision. The UAD assay and corresponding positivity cutoff values were clinically validated by assessing 776 urine specimens obtained from patients with X-ray-confirmed CAP. The UAD assay demonstrated 97% sensitivity and 100% specificity using samples obtained from patients with bacteremic, blood culture-positive CAP. Importantly, the UAD assay identified Streptococcus pneumoniae (13 serotypes) in a proportion of individuals with nonbacteremic CAP, a patient population for which the pneumococcal etiology of CAP was previously difficult to assess. Therefore, the UAD assay provides a specific, noninvasive, sensitive, and reproducible tool to support vaccine efficacy as well as epidemiological evaluation of pneumococcal disease, including CAP, in adults.

Comparison of a commercial ELISA and an immunoperoxidase monolayer assay to detect antibodies directed against porcine respiratory and reproductive syndrome virus

NARCIS (Netherlands)

Nodelijk, G.; Wensvoort, G.; Kroese, B.; Leengoed, van L.A.M.G.; Colijn, E.; Verheijden, J.H.M.

1996-01-01

A commercially available enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies against porcine respiratory and reproductive syndrome virus (PRRSV) was compared to an immunoperoxidase monolayer assay (IPMA). Serum samples used were collected from pigs experimentally infected with

Recommendations for adaptation and validation of commercial kits for biomarker quantification in drug development.

Science.gov (United States)

Khan, Masood U; Bowsher, Ronald R; Cameron, Mark; Devanarayan, Viswanath; Keller, Steve; King, Lindsay; Lee, Jean; Morimoto, Alyssa; Rhyne, Paul; Stephen, Laurie; Wu, Yuling; Wyant, Timothy; Lachno, D Richard

2015-01-01

Increasingly, commercial immunoassay kits are used to support drug discovery and development. Longitudinally consistent kit performance is crucial, but the degree to which kits and reagents are characterized by manufacturers is not standardized, nor are the approaches by users to adapt them and evaluate their performance through validation prior to use. These factors can negatively impact data quality. This paper offers a systematic approach to assessment, method adaptation and validation of commercial immunoassay kits for quantification of biomarkers in drug development, expanding upon previous publications and guidance. These recommendations aim to standardize and harmonize user practices, contributing to reliable biomarker data from commercial immunoassays, thus, enabling properly informed decisions during drug development.

Assessment of a recombinant androgen receptor binding assay: initial steps towards validation.

Science.gov (United States)

Freyberger, Alexius; Weimer, Marc; Tran, Hoai-Son; Ahr, Hans-Jürgen

2010-08-01

Despite more than a decade of research in the field of endocrine active compounds with affinity for the androgen receptor (AR), still no validated recombinant AR binding assay is available, although recombinant AR can be obtained from several sources. With funding from the European Union (EU)-sponsored 6th framework project, ReProTect, we developed a model protocol for such an assay based on a simple AR binding assay recently developed at our institution. Important features of the protocol were the use of a rat recombinant fusion protein to thioredoxin containing both the hinge region and ligand binding domain (LBD) of the rat AR (which is identical to the human AR-LBD) and performance in a 96-well plate format. Besides two reference compounds [dihydrotestosterone (DHT), androstenedione] ten test compounds with different affinities for the AR [levonorgestrel, progesterone, prochloraz, 17alpha-methyltestosterone, flutamide, norethynodrel, o,p'-DDT, dibutylphthalate, vinclozolin, linuron] were used to explore the performance of the assay. At least three independent experiments per compound were performed. The AR binding properties of reference and test compounds were well detected, in terms of the relative ranking of binding affinities, there was good agreement with published data obtained from experiments using recombinant AR preparations. Irrespective of the chemical nature of the compound, individual IC(50)-values for a given compound varied by not more than a factor of 2.6. Our data demonstrate that the assay reliably ranked compounds with strong, weak, and no/marginal affinity for the AR with high accuracy. It avoids the manipulation and use of animals, as a recombinant protein is used and thus contributes to the 3R concept. On the whole, this assay is a promising candidate for further validation. Copyright 2009 Elsevier Inc. All rights reserved.

Application of commercial enzyme linked immunosorbent assays (ELISA for the detection of antibodies for foot-and-mouth disease virus in wild boar and red deer

Directory of Open Access Journals (Sweden)

Terzić Svjetlana

2012-01-01

Full Text Available For detecting antibodies towards foot and mouth (FMD virus in sera collected from red deer hinds (Cervus elaphus and wild boars (Sus scrofa, three commercially available enzyme-linked immunosorbent assays (ELISA were used. Two ELISA kits (PrioCHECK FMDV NS and CHEKIT FMD-3ABC were used for the detection of antibodies towards non-structural proteins of FMD virus and one assay was based on the detection of antibodies for serotype O (PrioCHECK FMDV type O. All of the sera tested in our study were negative for antibodies against FMD virus. The aim of this study was to investigate the usefulness of commercially available ELISA kits given for marketing authorization in Croatia in testing the prevalence of FMD antibodies in wild boar and red deer populations. Since the producers of ELISA kits used in our study did not declare wild animals as a target species, we hypothesised that the same kits could be used for serological diagnosis of FMD in red deer and wild boars. Our study confirmed that the kits used are acceptable for detecting antibodies in both species tested, however, the investigation highlighted the problem of validating the kits due to the absence of available positive sera originating from red deer, as well as other susceptible species, especially artiodactyls.

Validation of commercially available automated canine-specific immunoturbidimetric method for measuring canine C-reactive protein

DEFF Research Database (Denmark)

Hillström, Anna; Hagman, Ragnvi; Tvedten, Harold

2014-01-01

BACKGROUND: Measurement of C-reactive protein (CRP) is used for diagnosing and monitoring systemic inflammatory disease in canine patients. An automated human immunoturbidimetric assay has been validated for measuring canine CRP, but cross-reactivity with canine CRP is unpredictable. OBJECTIVE......: The purpose of the study was to validate a new automated canine-specific immunoturbidimetric CRP method (Gentian cCRP). METHODS: Studies of imprecision, accuracy, prozone effect, interference, limit of quantification, and stability under different storage conditions were performed. The new method was compared...... with a human CRP assay previously validated for canine CRP determination. Samples from 40 healthy dogs were analyzed to establish a reference interval. RESULTS: Total imprecision was

Development and validation of a luminescence-based, medium-throughput assay for drug screening in Schistosoma mansoni.

Directory of Open Access Journals (Sweden)

Cristiana Lalli

2015-01-01

Full Text Available Schistosomiasis, one of the world's greatest neglected tropical diseases, is responsible for over 280,000 human deaths per annum. Praziquantel, developed in the 1970s, has high efficacy, excellent tolerability, few and transient side effects, simple administration procedures and competitive cost and it is currently the only recommended drug for treatment of human schistosomiasis. The use of a single drug to treat a population of over 200 million infected people appears particularly alarming when considering the threat of drug resistance. Quantitative, objective and validated methods for the screening of compound collections are needed for the discovery of novel anti-schistosomal drugs.The present work describes the development and validation of a luminescence-based, medium-throughput assay for the detection of schistosomula viability through quantitation of ATP, a good indicator of metabolically active cells in culture. This validated method is demonstrated to be fast, highly reliable, sensitive and automation-friendly. The optimized assay was used for the screening of a small compound library on S. mansoni schistosomula, showing that the proposed method is suitable for a medium-throughput semi-automated screening. Interestingly, the pilot screening identified hits previously reported to have some anti-parasitic activity, further supporting the validity of this assay for anthelminthic drug discovery.The developed and validated schistosomula viability luminescence-based assay was shown to be successful and suitable for the identification of novel compounds potentially exploitable in future schistosomiasis therapies.

Development and validation of Burkholderia pseudomallei-specific real-time PCR assays for clinical, environmental or forensic detection applications.

Directory of Open Access Journals (Sweden)

Erin P Price

Full Text Available The bacterium Burkholderia pseudomallei causes melioidosis, a rare but serious illness that can be fatal if untreated or misdiagnosed. Species-specific PCR assays provide a technically simple method for differentiating B. pseudomallei from near-neighbor species. However, substantial genetic diversity and high levels of recombination within this species reduce the likelihood that molecular signatures will differentiate all B. pseudomallei from other Burkholderiaceae. Currently available molecular assays for B. pseudomallei detection lack rigorous validation across large in silico datasets and isolate collections to test for specificity, and none have been subjected to stringent quality control criteria (accuracy, precision, selectivity, limit of quantitation (LoQ, limit of detection (LoD, linearity, ruggedness and robustness to determine their suitability for environmental, clinical or forensic investigations. In this study, we developed two novel B. pseudomallei specific assays, 122018 and 266152, using a dual-probe approach to differentiate B. pseudomallei from B. thailandensis, B. oklahomensis and B. thailandensis-like species; other species failed to amplify. Species specificity was validated across a large DNA panel (>2,300 samples comprising Burkholderia spp. and non-Burkholderia bacterial and fungal species of clinical and environmental relevance. Comparison of assay specificity to two previously published B. pseudomallei-specific assays, BurkDiff and TTS1, demonstrated comparable performance of all assays, providing between 99.7 and 100% specificity against our isolate panel. Last, we subjected 122018 and 266152 to rigorous quality control analyses, thus providing quantitative limits of assay performance. Using B. pseudomallei as a model, our study provides a framework for comprehensive quantitative validation of molecular assays and provides additional, highly validated B. pseudomallei assays for the scientific research community.

Comparative analytical evaluation of the respiratory TaqMan Array Card with real-time PCR and commercial multi-pathogen assays.

Science.gov (United States)

Harvey, John J; Chester, Stephanie; Burke, Stephen A; Ansbro, Marisela; Aden, Tricia; Gose, Remedios; Sciulli, Rebecca; Bai, Jing; DesJardin, Lucy; Benfer, Jeffrey L; Hall, Joshua; Smole, Sandra; Doan, Kimberly; Popowich, Michael D; St George, Kirsten; Quinlan, Tammy; Halse, Tanya A; Li, Zhen; Pérez-Osorio, Ailyn C; Glover, William A; Russell, Denny; Reisdorf, Erik; Whyte, Thomas; Whitaker, Brett; Hatcher, Cynthia; Srinivasan, Velusamy; Tatti, Kathleen; Tondella, Maria Lucia; Wang, Xin; Winchell, Jonas M; Mayer, Leonard W; Jernigan, Daniel; Mawle, Alison C

2016-02-01

In this study, a multicenter evaluation of the Life Technologies TaqMan(®) Array Card (TAC) with 21 custom viral and bacterial respiratory assays was performed on the Applied Biosystems ViiA™ 7 Real-Time PCR System. The goal of the study was to demonstrate the analytical performance of this platform when compared to identical individual pathogen specific laboratory developed tests (LDTs) designed at the Centers for Disease Control and Prevention (CDC), equivalent LDTs provided by state public health laboratories, or to three different commercial multi-respiratory panels. CDC and Association of Public Health Laboratories (APHL) LDTs had similar analytical sensitivities for viral pathogens, while several of the bacterial pathogen APHL LDTs demonstrated sensitivities one log higher than the corresponding CDC LDT. When compared to CDC LDTs, TAC assays were generally one to two logs less sensitive depending on the site performing the analysis. Finally, TAC assays were generally more sensitive than their counterparts in three different commercial multi-respiratory panels. TAC technology allows users to spot customized assays and design TAC layout, simplify assay setup, conserve specimen, dramatically reduce contamination potential, and as demonstrated in this study, analyze multiple samples in parallel with good reproducibility between instruments and operators. Copyright © 2015 Elsevier B.V. All rights reserved.

Analytic Validation of Immunohistochemistry Assays: New Benchmark Data From a Survey of 1085 Laboratories.

Science.gov (United States)

Stuart, Lauren N; Volmar, Keith E; Nowak, Jan A; Fatheree, Lisa A; Souers, Rhona J; Fitzgibbons, Patrick L; Goldsmith, Jeffrey D; Astles, J Rex; Nakhleh, Raouf E

2017-09-01

- A cooperative agreement between the College of American Pathologists (CAP) and the United States Centers for Disease Control and Prevention was undertaken to measure laboratories' awareness and implementation of an evidence-based laboratory practice guideline (LPG) on immunohistochemical (IHC) validation practices published in 2014. - To establish new benchmark data on IHC laboratory practices. - A 2015 survey on IHC assay validation practices was sent to laboratories subscribed to specific CAP proficiency testing programs and to additional nonsubscribing laboratories that perform IHC testing. Specific questions were designed to capture laboratory practices not addressed in a 2010 survey. - The analysis was based on responses from 1085 laboratories that perform IHC staining. Ninety-six percent (809 of 844) always documented validation of IHC assays. Sixty percent (648 of 1078) had separate procedures for predictive and nonpredictive markers, 42.7% (220 of 515) had procedures for laboratory-developed tests, 50% (349 of 697) had procedures for testing cytologic specimens, and 46.2% (363 of 785) had procedures for testing decalcified specimens. Minimum case numbers were specified by 85.9% (720 of 838) of laboratories for nonpredictive markers and 76% (584 of 768) for predictive markers. Median concordance requirements were 95% for both types. For initial validation, 75.4% (538 of 714) of laboratories adopted the 20-case minimum for nonpredictive markers and 45.9% (266 of 579) adopted the 40-case minimum for predictive markers as outlined in the 2014 LPG. The most common method for validation was correlation with morphology and expected results. Laboratories also reported which assay changes necessitated revalidation and their minimum case requirements. - Benchmark data on current IHC validation practices and procedures may help laboratories understand the issues and influence further refinement of LPG recommendations.

Clinical evaluation of a helicase-dependant amplification (HDA)-based commercial assay for the simultaneous detection of HSV-1 and HSV-2.

Science.gov (United States)

Teo, Jeanette W P; Chiang, Donald; Jureen, Roland; Lin, Raymond T P

2015-11-01

In this study, we evaluate the performance of a commercial assay, the AmpliVue HSV 1+2 Assay (Quidel), which employs HDA for the detection of both HSV-1 and HSV-2. The assay was tested on 307 clinical specimens (genital, oral, and dermal). When compared to shell vial virus culture and immunofluorescence typing of HSV, the positive percent agreement and negative percent agreement values were 98.2% and 90.9%, respectively. Excellent assay performance was demonstrated. Copyright © 2015 Elsevier Inc. All rights reserved.

Validation of the 3D Skin Comet assay using full thickness skin models: Transferability and reproducibility.

Science.gov (United States)

Reisinger, Kerstin; Blatz, Veronika; Brinkmann, Joep; Downs, Thomas R; Fischer, Anja; Henkler, Frank; Hoffmann, Sebastian; Krul, Cyrille; Liebsch, Manfred; Luch, Andreas; Pirow, Ralph; Reus, Astrid A; Schulz, Markus; Pfuhler, Stefan

2018-03-01

Recently revised OECD Testing Guidelines highlight the importance of considering the first site-of-contact when investigating the genotoxic hazard. Thus far, only in vivo approaches are available to address the dermal route of exposure. The 3D Skin Comet and Reconstructed Skin Micronucleus (RSMN) assays intend to close this gap in the in vitro genotoxicity toolbox by investigating DNA damage after topical application. This represents the most relevant route of exposure for a variety of compounds found in household products, cosmetics, and industrial chemicals. The comet assay methodology is able to detect both chromosomal damage and DNA lesions that may give rise to gene mutations, thereby complementing the RSMN which detects only chromosomal damage. Here, the comet assay was adapted to two reconstructed full thickness human skin models: the EpiDerm™- and Phenion ® Full-Thickness Skin Models. First, tissue-specific protocols for the isolation of single cells and the general comet assay were transferred to European and US-American laboratories. After establishment of the assay, the protocol was then further optimized with appropriate cytotoxicity measurements and the use of aphidicolin, a DNA repair inhibitor, to improve the assay's sensitivity. In the first phase of an ongoing validation study eight chemicals were tested in three laboratories each using the Phenion ® Full-Thickness Skin Model, informing several validation modules. Ultimately, the 3D Skin Comet assay demonstrated a high predictive capacity and good intra- and inter-laboratory reproducibility with four laboratories reaching a 100% predictivity and the fifth yielding 70%. The data are intended to demonstrate the use of the 3D Skin Comet assay as a new in vitro tool for following up on positive findings from the standard in vitro genotoxicity test battery for dermally applied chemicals, ultimately helping to drive the regulatory acceptance of the assay. To expand the database, the validation will

The relative test performance characteristics of two commercial assays for the detection of Mycobacterium tuberculosis complex in paraffin-fixed human biopsy specimens

Directory of Open Access Journals (Sweden)

Broukhanski George

2008-09-01

Full Text Available Abstract The Seeplex™ TB Detection-2 assay (Rockville, MD is a nested endpoint PCR for the Mycobacterium tuberculosis complex (MTBC targets IS6110 and MPB64 that utilizes dual priming oligonucleotide technology. When used to detect the presence of MTBC DNA in formalin-fixed paraffin-embedded tissue specimens, the sensitivity and specificity of this assay is equivalent to a labor-intensive traditional endpoint PCR assay and is more sensitive than a commercial real-time PCR assay.

Development and validation of cell-based luciferase reporter gene assays for measuring neutralizing anti-drug antibodies against interferon beta.

Science.gov (United States)

Hermanrud, Christina; Ryner, Malin; Luft, Thomas; Jensen, Poul Erik; Ingenhoven, Kathleen; Rat, Dorothea; Deisenhammer, Florian; Sørensen, Per Soelberg; Pallardy, Marc; Sikkema, Dan; Bertotti, Elisa; Kramer, Daniel; Creeke, Paul; Fogdell-Hahn, Anna

2016-03-01

Neutralizing anti-drug antibodies (NAbs) against therapeutic interferon beta (IFNβ) in people with multiple sclerosis (MS) are measured with cell-based bioassays. The aim of this study was to redevelop and validate two luciferase reporter-gene bioassays, LUC and iLite, using a cut-point approach to identify NAb positive samples. Such an approach is favored by the pharmaceutical industry and governmental regulatory agencies as it has a clear statistical basis and overcomes the limitations of the current assays based on the Kawade principle. The work was conducted following the latest assay guidelines. The assays were re-developed and validated as part of the "Anti-Biopharmaceutical Immunization: Prediction and analysis of clinical relevance to minimize the risk" (ABIRISK) consortium and involved a joint collaboration between four academic laboratories and two pharmaceutical companies. The LUC assay was validated at Innsbruck Medical University (LUCIMU) and at Rigshospitalet (LUCRH) Copenhagen, and the iLite assay at Karolinska Institutet, Stockholm. For both assays, the optimal serum sample concentration in relation to sensitivity and recovery was 2.5% (v/v) in assay media. A Shapiro-Wilk test indicated a normal distribution for the majority of runs, allowing a parametric approach for cut-point calculation to be used, where NAb positive samples could be identified with 95% confidence. An analysis of means and variances indicated that a floating cut-point should be used for all assays. The assays demonstrated acceptable sensitivity for being cell-based assays, with a confirmed limit of detection in neat serum of 1519 ng/mL for LUCIMU, 814 ng/mL for LUCRH, and 320 ng/mL for iLite. Use of the validated cut-point assay, in comparison with the previously used Kawade method, identified 14% more NAb positive samples. In conclusion, implementation of the cut-point design resulted in increased sensitivity to detect NAbs. However, the clinical significance of these low

Use of statistical analysis to validate ecogenotoxicology findings arising from various comet assay components.

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Hussain, Bilal; Sultana, Tayyaba; Sultana, Salma; Al-Ghanim, Khalid Abdullah; Masoud, Muhammad Shahreef; Mahboob, Shahid

2018-04-01

Cirrhinus mrigala, Labeo rohita, and Catla catla are economically important fish for human consumption in Pakistan, but industrial and sewage pollution has drastically reduced their population in the River Chenab. Statistics are an important tool to analyze and interpret comet assay results. The specific aims of the study were to determine the DNA damage in Cirrhinus mrigala, Labeo rohita, and Catla catla due to chemical pollution and to assess the validity of statistical analyses to determine the viability of the comet assay for a possible use with these freshwater fish species as a good indicator of pollution load and habitat degradation. Comet assay results indicated a significant (P comet head diameter, comet tail length, and % DNA damage. Regression analysis and correlation matrices conducted among the parameters of the comet assay affirmed the precision and the legitimacy of the results. The present study, therefore, strongly recommends that genotoxicological studies conduct appropriate analysis of the various components of comet assays to offer better interpretation of the assay data.

Evolution of Quality Assurance for Clinical Immunohistochemistry in the Era of Precision Medicine. Part 3: Technical Validation of Immunohistochemistry (IHC) Assays in Clinical IHC Laboratories.

Science.gov (United States)

Torlakovic, Emina E; Cheung, Carol C; D'Arrigo, Corrado; Dietel, Manfred; Francis, Glenn D; Gilks, C Blake; Hall, Jacqueline A; Hornick, Jason L; Ibrahim, Merdol; Marchetti, Antonio; Miller, Keith; van Krieken, J Han; Nielsen, Soren; Swanson, Paul E; Vyberg, Mogens; Zhou, Xiaoge; Taylor, Clive R

2017-03-01

Validation of immunohistochemistry (IHC) assays is a subject that is of great importance to clinical practice as well as basic research and clinical trials. When applied to clinical practice and focused on patient safety, validation of IHC assays creates objective evidence that IHC assays used for patient care are "fit-for-purpose." Validation of IHC assays needs to be properly informed by and modeled to assess the purpose of the IHC assay, which will further determine what sphere of validation is required, as well as the scope, type, and tier of technical validation. These concepts will be defined in this review, part 3 of the 4-part series "Evolution of Quality Assurance for Clinical Immunohistochemistry in the Era of Precision Medicine."

Analytic validation and comparison of three commercial immunoassays for measurement of plasma atrial/A-type natriuretic peptide concentration in horses

DEFF Research Database (Denmark)

Trachsel, D S; Schwarzwald, C C; Grenacher, B

2014-01-01

Measurement of atrial/A-type natriuretic peptide (ANP) concentrations may be of use for assessment of cardiac disease, and reliable data on the analytic performance of available assays are needed. To assess the suitability for clinical use of commercially available ANP assays, intra-assay and inter......-Altman analyses. For all assays, precision was moderate but acceptable and dilution parallelism was good. All assays showed analytic performance similar to other immunoassays used in veterinary medicine. However, the results from the three assays were poorly comparable. Our study highlights the need...

Comparison of two commercial carbapenemase gene confirmatory assays in multiresistant Enterobacteriaceae and Acinetobacter baumannii-complex.

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Rösner, Stephan; Gehlweiler, Kevin; Küsters, Uta; Kolbert, Mathias; Hübner, Kirsten; Pfennigwerth, Niels; Mack, Dietrich

2018-01-01

Multidrug-resistant Gram-negative bacilli (MDR-GNB) producing carbapenemases are increasing at an alarming speed. Rapid confirmation of carbapenemase type will be an important diagnostic step in clinical microbiology laboratories not only to reduce the risk of transmissions but also for optimising antibiotic therapy in the future. We compared diagnostic reliability of two commercially available molecular assays (Check-Direct CPE vs. AID line probe assay) for detection and typing of carbapenemase genes in 80 well-characterized isolates of MDR-GNB. Respective strains were isolated in various clinical specimens at our clinical microbiology laboratory. The reference standard included confirmation of carbapenemase-production at the molecular level at the German National Reference Laboratory for Multidrug-resistant Gram-negative bacteria (Ruhr-University Bochum, Germany). 53 Enterobacteriaceae and 27 members of the A. baumannii-complex were used in this study. The tested assays appeared highly reliable to confirm carbapenemase-producing Enterobacteriaceae (CPE) with respective sensitivities of 97.7%, but are currently unsuitable for analysis of members of the A. baumannii-complex. Both assays are easy to perform and rapid tools for confirmation and typing of the most common carbapenemase genes in Enterobacteriaceae. Implementation should be possible for any clinical microbiology laboratory with Check-Direct CPE being easier to handle and having less technological requirements.

Comparison of two commercial carbapenemase gene confirmatory assays in multiresistant Enterobacteriaceae and Acinetobacter baumannii-complex.

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Stephan Rösner

Full Text Available Multidrug-resistant Gram-negative bacilli (MDR-GNB producing carbapenemases are increasing at an alarming speed. Rapid confirmation of carbapenemase type will be an important diagnostic step in clinical microbiology laboratories not only to reduce the risk of transmissions but also for optimising antibiotic therapy in the future. We compared diagnostic reliability of two commercially available molecular assays (Check-Direct CPE vs. AID line probe assay for detection and typing of carbapenemase genes in 80 well-characterized isolates of MDR-GNB. Respective strains were isolated in various clinical specimens at our clinical microbiology laboratory. The reference standard included confirmation of carbapenemase-production at the molecular level at the German National Reference Laboratory for Multidrug-resistant Gram-negative bacteria (Ruhr-University Bochum, Germany. 53 Enterobacteriaceae and 27 members of the A. baumannii-complex were used in this study. The tested assays appeared highly reliable to confirm carbapenemase-producing Enterobacteriaceae (CPE with respective sensitivities of 97.7%, but are currently unsuitable for analysis of members of the A. baumannii-complex. Both assays are easy to perform and rapid tools for confirmation and typing of the most common carbapenemase genes in Enterobacteriaceae. Implementation should be possible for any clinical microbiology laboratory with Check-Direct CPE being easier to handle and having less technological requirements.

Microbiological assay for the analysis of certain macrolides in pharmaceutical dosage forms.

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Mahmoudi, A; Fourar, R E-A; Boukhechem, M S; Zarkout, S

2015-08-01

Clarithromycin (CLA) and roxithromycin (ROX) are macrolide antibiotics with an expanded spectrum of activity that are commercially available as tablets. A microbiological assay, applying the cylinder-plate method and using a strain of Micrococcus luteus ATCC 9341 as test organism, has been used and validated for the quantification of two macrolide drugs; CLA and ROX in pure and pharmaceutical formulations. The validation of the proposed method was carried out for linearity, precision, accuracy and specificity. The linear dynamic ranges were from 0.1 to 0.5μg/mL for both compounds. Logarithmic calibration curve was obtained for each macrolide (r>0.989) with statistically equal slopes varying from 3.275 to 4.038, and a percentage relative standard deviation in the range of 0.24-0.92%. Moreover, the method was applied successfully for the assay of the studied drugs in pharmaceutical tablet dosage forms. Recovery from standard addition experiments in commercial products was 94.71-96.91% regarding clarithromycin and 93.94-98.12% regarding roxithromycin, with a precision (%RSD) 1.32-2.11%. Accordingly, this microbiological assay can be used for routine quality control analysis of titled drugs in tablet formulations. Copyright © 2015 Elsevier B.V. All rights reserved.

Diagnostic performance of a commercial immunoblot assay for myositis antibody testing.

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Bundell, Chris; Rojana-Udomsart, Arada; Mastaglia, Frank; Hollingsworth, Peter; McLean-Tooke, Andrew

2016-06-01

The objective of this study was to establish a population based reference range for a commercial immunoblot assay detecting myositis specific autoantibodies (MSAs) and myositis associated autoantibodies (MAAs), and to assess the diagnostic performance of this reference range against the manufacturer's recommended ranges in a myositis patient cohort. A total of 124 patients from a myositis cohort and 197 healthy controls were serologically assessed using a commercial immunoblot containing eleven autoantigens (Jo-1, EJ, OJ, PL7, PL12, Mi-2, SRP, Ku, PMScl75, PMScl100 and Ro52) according to the manufacturer's instructions. Use of the manufacturer's reference ranges resulted in detection of MSAs in 19.4% of myositis patients and 9.1% of controls; MAAs were detected in 41.1% of myositis patients and 14.2% of controls. Reference values derived from the healthy control population resulted in significant differences in cut-off values for some autoantibodies, particularly Ro52 and PMScl75. Use of local reference ranges reduced detection of MSAs to 16.9% of myositis patients and 3% of healthy controls, with MAAs 23.4% of patients and 2% of healthy controls. Application of population based reference ranges resulted in significant differences in detection of MSAs and MAAs compared to the manufacturer's recommended ranges. Cut-off levels should be assessed to ensure suitability for the population tested. Copyright © 2016. Published by Elsevier B.V.

Development and validation of a Luminex assay for detection of a predictive biomarker for PROSTVAC-VF therapy

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Lucas, Julie L.; Tacheny, Erin A.; Ferris, Allison; Galusha, Michelle; Srivastava, Apurva K.; Ganguly, Aniruddha; Williams, P. Mickey; Sachs, Michael C.; Thurin, Magdalena; Tricoli, James V.; Ricker, Winnie; Gildersleeve, Jeffrey C.

2017-01-01

Cancer therapies can provide substantially improved survival in some patients while other seemingly similar patients receive little or no benefit. Strategies to identify patients likely to respond well to a given therapy could significantly improve health care outcomes by maximizing clinical benefits while reducing toxicities and adverse effects. Using a glycan microarray assay, we recently reported that pretreatment serum levels of IgM specific to blood group A trisaccharide (BG-Atri) correlate positively with overall survival of cancer patients on PROSTVAC-VF therapy. The results suggested anti-BG-Atri IgM measured prior to treatment could serve as a biomarker for identifying patients likely to benefit from PROSTVAC-VF. For continued development and clinical application of serum IgM specific to BG-Atri as a predictive biomarker, a clinical assay was needed. In this study, we developed and validated a Luminex-based clinical assay for measuring serum IgM specific to BG-Atri. IgM levels were measured with the Luminex assay and compared to levels measured using the microarray for 126 healthy individuals and 77 prostate cancer patients. This assay provided reproducible and consistent results with low %CVs, and tolerance ranges were established for the assay. IgM levels measured using the Luminex assay were found to be highly correlated to the microarray results with R values of 0.93–0.95. This assay is a Laboratory Developed Test (LDT) and is suitable for evaluating thousands of serum samples in CLIA certified laboratories that have validated the assay. In addition, the study demonstrates that discoveries made using neoglycoprotein-based microarrays can be readily migrated to a clinical assay. PMID:28771597

Validation of a Salmonella loop-mediated isothermal amplification assay in animal food.

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Domesle, Kelly J; Yang, Qianru; Hammack, Thomas S; Ge, Beilei

2018-01-02

Loop-mediated isothermal amplification (LAMP) has emerged as a promising alternative to PCR for pathogen detection in food testing and clinical diagnostics. This study aimed to validate a Salmonella LAMP method run on both turbidimetry (LAMP I) and fluorescence (LAMP II) platforms in representative animal food commodities. The U.S. Food and Drug Administration (FDA)'s culture-based Bacteriological Analytical Manual (BAM) method was used as the reference method and a real-time quantitative PCR (qPCR) assay was also performed. The method comparison study followed the FDA's microbiological methods validation guidelines, which align well with those from the AOAC International and ISO. Both LAMP assays were 100% specific among 300 strains (247 Salmonella of 185 serovars and 53 non-Salmonella) tested. The detection limits ranged from 1.3 to 28 cells for six Salmonella strains of various serovars. Six commodities consisting of four animal feed items (cattle feed, chicken feed, horse feed, and swine feed) and two pet food items (dry cat food and dry dog food) all yielded satisfactory results. Compared to the BAM method, the relative levels of detection (RLODs) for LAMP I ranged from 0.317 to 1 with a combined value of 0.610, while those for LAMP II ranged from 0.394 to 1.152 with a combined value of 0.783, which all fell within the acceptability limit (2.5) for an unpaired study. This also suggests that LAMP was more sensitive than the BAM method at detecting low-level Salmonella contamination in animal food and results were available 3days sooner. The performance of LAMP on both platforms was comparable to that of qPCR but notably faster, particularly LAMP II. Given the importance of Salmonella in animal food safety, the LAMP assays validated in this study holds great promise as a rapid, reliable, and robust method for routine screening of Salmonella in these commodities. Published by Elsevier B.V.

Comparison of Laboratory-Developed and Commercial Monoclonal Antibody-Based Sandwich Enzyme-Linked Immunosorbent Assays for Almond (Prunus dulcis) Detection and Quantification.

Science.gov (United States)

Liu, Changqi; Chhabra, Guneet S; Zhao, Jing; Zaffran, Valerie D; Gupta, Sahil; Roux, Kenneth H; Gradziel, Thomas M; Sathe, Shridhar K

2017-10-01

A commercially available monoclonal antibody (mAb)-based direct sandwich enzyme-linked immunosorbent assay (ELISA) kit (BioFront Technologies, Tallahassee, Fla., U.S.A.) was compared with an in-house developed mAb 4C10-based ELISA for almond detection. The assays were comparable in sensitivity (limit of detection almond, limit of quantification almond), specificity (no cross-reactivity with 156 tested foods at a concentration of 100000 ppm whole sample), and reproducibility (intra- and interassay variability almond seeds subjected to autoclaving, blanching, frying, microwaving, and dry roasting. The almond recovery ranges for spiked food matrices were 84.3% to 124.6% for 4C10 ELISA and 81.2% to 127.4% for MonoTrace ELISA. The almond recovery ranges for commercial and laboratory prepared foods with declared/known almond amount were 30.9% to 161.2% for 4C10 ELISA and 38.1% to 207.6% for MonoTrace ELISA. Neither assay registered any false-positive or negative results among the tested commercial and laboratory prepared samples. Ability to detect and quantify trace amounts of almonds is important for improving safety of almond sensitive consumers. Two monoclonal antibody-based ELISAs were compared for almond detection. The information is useful to food industry, regulatory agencies, scientific community, and almond consumers. © 2017 Institute of Food Technologists®.

Development and Validation of HPLC-PDA Assay method of Frangula emodin

Directory of Open Access Journals (Sweden)

Deborah Duca

2016-03-01

Full Text Available Frangula emodin, (1,3,8-trihydroxy-6-methyl-anthraquinone, is one of the anthraquinone derivatives found abundantly in the roots and bark of a number of plant families traditionally used to treat constipation and haemorrhoids. The present study describes the development and subsequent validation of a specific Assay HPLC method for emodin. The separation was achieved on a Waters Symmetry C18, 4.6 × 250 mm, 5 μm particle size, column at a temperature of 35 °C, with UV detection at 287 and 436 nm. An isocratic elution mode consisting of 0.1% formic acid and 0.01% trifluoroacetic acid as the aqueous mobile phase, and methanol was used. The method was successfully and statistically validated for linearity, range, precision, accuracy, specificity and solution stability.

Precision and linearity targets for validation of an IFNγ ELISPOT, cytokine flow cytometry, and tetramer assay using CMV peptides

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Lyerly Herbert K

2008-03-01

Full Text Available Abstract Background Single-cell assays of immune function are increasingly used to monitor T cell responses in immunotherapy clinical trials. Standardization and validation of such assays are therefore important to interpretation of the clinical trial data. Here we assess the levels of intra-assay, inter-assay, and inter-operator precision, as well as linearity, of CD8+ T cell IFNγ-based ELISPOT and cytokine flow cytometry (CFC, as well as tetramer assays. Results Precision was measured in cryopreserved PBMC with a low, medium, or high response level to a CMV pp65 peptide or peptide mixture. Intra-assay precision was assessed using 6 replicates per assay; inter-assay precision was assessed by performing 8 assays on different days; and inter-operator precision was assessed using 3 different operators working on the same day. Percent CV values ranged from 4% to 133% depending upon the assay and response level. Linearity was measured by diluting PBMC from a high responder into PBMC from a non-responder, and yielded R2 values from 0.85 to 0.99 depending upon the assay and antigen. Conclusion These data provide target values for precision and linearity of single-cell assays for those wishing to validate these assays in their own laboratories. They also allow for comparison of the precision and linearity of ELISPOT, CFC, and tetramer across a range of response levels. There was a trend toward tetramer assays showing the highest precision, followed closely by CFC, and then ELISPOT; while all three assays had similar linearity. These findings are contingent upon the use of optimized protocols for each assay.

Development and Validation of a Microbiological Agar Assay for Determination of Orbifloxacin in Pharmaceutical Preparations

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Hérida R. N. Salgado

2011-08-01

Full Text Available Orbifloxacin is a fluoroquinolone with broad-spectrum antimicrobial activity, and belongs to the third generation of quinolones. Regarding the quality control of medicines, a validated microbiological assay for determination of orbifloxacin in pharmaceutical formulations has not as yet been reported. For this purpose, this paper reports the development and validation of a simple, sensitive, accurate and reproducible agar diffusion method to quantify orbifloxacin in tablet formulations. The assay is based on the inhibitory effect of orbifloxacin upon the strain of Staphylococcus aureus ATCC 25923 used as test microorganism. The results were treated statistically by analysis of variance and were found to be linear (r = 0.9992 in the selected range of 16.0–64.0 μg/mL, precise with relative standard deviation (RSD of repeatability intraday = 2.88%, intermediate precision RSD = 3.33%, and accurate (100.31%. The results demonstrated the validity of the proposed bioassay, which allows reliable orbifloxacin quantitation in pharmaceutical samples and therefore can be used as a useful alternative methodology for the routine quality control of this medicine.

Improved quantification of a commercial enzyme-linked immunosorbent assay kit for measuring anti-MDA5 antibody.

Science.gov (United States)

Gono, Takahisa; Okazaki, Yuka; Murakami, Akihiro; Kuwana, Masataka

2018-04-09

To compare the quantitative performance for measuring anti-MDA5 antibody titer of two enzyme-linked immunosorbent assay (ELISA) systems: an in-house ELISA and the commercial MESACUP TM anti-MDA5 test. Anti-MDA5 antibody titer was measured in sera from 70 patients with dermatomyositis using an in-house ELISA and the MESACUP TM anti-MDA5 test side-by-side. For the commercial ELISA kit, serum samples diluted 1:101 were used according to the manufacturer's protocol, but serial dilutions of sera were also examined to identify the optimal serum dilution for quantification. The anti-MDA5 antibody titers measured by the in-house and commercial ELISAs were positively correlated with each other (r = 0.53, p = .0001), but the antibody titer measured by the commercial ELISA was less sensitive to change after medical treatment, and 37 (80%) of 46 anti-MDA5-positive sera had antibody titer exceeding the quantification range specified by the manufacturer (≥150 index). Experiments using diluted serum samples revealed that diluting the sera 1:5050 improved the quantitative performance of the MESACUP TM anti-MDA5 test, including a better correlation with the in-house ELISA results and an increased sensitivity to change. We improved the ability of the commercial ELISA kit to quantify anti-MDA5 antibody titer by altering its protocol.

OECD validation of the Hershberger assay in Japan: phase 2 dose response of methyltestosterone, vinclozolin, and p,p'-DDE.

Science.gov (United States)

Yamasaki, Kanji; Sawaki, Masakuni; Ohta, Ryo; Okuda, Hirokazu; Katayama, Seiichi; Yamada, Tomoya; Ohta, Takafumi; Kosaka, Tadashi; Owens, William

2003-01-01

The Organisation for Economic Co-operation and Development has initiated the development of new guidelines for the screening and testing of potential endocrine disruptors. The Hershberger assay is one of the assays selected for validation based on the need for in vivo screening to detect androgen agonists or antagonists by measuring the response of five sex accessory organs and tissues of castrated juvenile male rats: the ventral prostate, the seminal vesicles with coagulating glands, the levator ani and bulbocavernosus muscle complex, the Cowper's glands, and the glans penis. The phase 1 feasibility demonstration stage of the Hershberger validation program has been successfully completed with a single androgen agonist and a single antagonist as reference substances. The phase 2 validation program employs a range of additional androgen agonists and antagonists as well as 5alpha-reductase inhibitors. Seven Japanese laboratories have contributed phase 2 validation studies of the Hershberger assay using methyltestosterone, vinclozolin, and 2,2-bis (4-chlorophenyl)-1,1-dichloroethylene (p,p'-DDE). The methyltestosterone doses were 0, 0.05, 0.5, 5, and 50 mg/kg/day, and the vinclozolin and p,p'-DDE doses were 0, 3, 10, 30, and 100 mg/kg/day. All chemicals were orally administered by gavage for 10 consecutive days. In the antagonist version of the assay using vinclozolin and p,p'-DDE, 0.2 mg/kg/day of testosterone propionate was coadministered by subcutaneous injection. All five accessory sex preproductive organs and tissues consistently responded with statistically significant changes in weight within a narrow window. Therefore, the Japanese studies support the Hershberger assay as a reliable and reproducible screening assay for the detection of androgen agonistic and antagonistic effects. PMID:14644666

Transcriptome-Wide Single Nucleotide Polymorphisms (SNPs for Abalone (Haliotis midae: Validation and Application Using GoldenGate Medium-Throughput Genotyping Assays

Directory of Open Access Journals (Sweden)

Rouvay Roodt-Wilding

2013-09-01

Full Text Available Haliotis midae is one of the most valuable commercial abalone species in the world, but is highly vulnerable, due to exploitation, habitat destruction and predation. In order to preserve wild and cultured stocks, genetic management and improvement of the species has become crucial. Fundamental to this is the availability and employment of molecular markers, such as microsatellites and Single Nucleotide Polymorphisms (SNPs . Transcriptome sequences generated through sequencing-by-synthesis technology were utilized for the in vitro and in silico identification of 505 putative SNPs from a total of 316 selected contigs. A subset of 234 SNPs were further validated and characterized in wild and cultured abalone using two Illumina GoldenGate genotyping assays. Combined with VeraCode technology, this genotyping platform yielded a 65%−69% conversion rate (percentage polymorphic markers with a global genotyping success rate of 76%−85% and provided a viable means for validating SNP markers in a non-model species. The utility of 31 of the validated SNPs in population structure analysis was confirmed, while a large number of SNPs (174 were shown to be informative and are, thus, good candidates for linkage map construction. The non-synonymous SNPs (50 located in coding regions of genes that showed similarities with known proteins will also be useful for genetic applications, such as the marker-assisted selection of genes of relevance to abalone aquaculture.

Transcriptome-wide single nucleotide polymorphisms (SNPs) for abalone (Haliotis midae): validation and application using GoldenGate medium-throughput genotyping assays.

Science.gov (United States)

Bester-Van Der Merwe, Aletta; Blaauw, Sonja; Du Plessis, Jana; Roodt-Wilding, Rouvay

2013-09-23

Haliotis midae is one of the most valuable commercial abalone species in the world, but is highly vulnerable, due to exploitation, habitat destruction and predation. In order to preserve wild and cultured stocks, genetic management and improvement of the species has become crucial. Fundamental to this is the availability and employment of molecular markers, such as microsatellites and single nucleotide (SNPs). Transcriptome sequences generated through sequencing-by-synthesis technology were utilized for the in vitro and in silico identification of 505 putative SNPs from a total of 316 selected contigs. A subset of 234 SNPs were further validated and characterized in wild and cultured abalone using two Illumina GoldenGate genotyping assays. Combined with VeraCode technology, this genotyping platform yielded a 65%-69% conversion rate (percentage polymorphic markers) with a global genotyping success rate of 76%-85% and provided a viable means for validating SNP markers in a non-model species. The utility of 31 of the validated SNPs in population structure analysis was confirmed, while a large number of SNPs (174) were shown to be informative and are, thus, good candidates for linkage map construction. The non-synonymous SNPs (50) located in coding regions of genes that showed similarities with known proteins will also be useful for genetic applications, such as the marker-assisted selection of genes of relevance to abalone aquaculture.

Complete validation of a unique digestion assay to detect Trichinella larvae in horse meat demonstrates the reliability of this assay for meeting food safety and trade requirements.

Science.gov (United States)

Forbes, L B; Hill, D E; Parker, S; Tessaro, S V; Gamble, H R; Gajadhar, A A

2008-03-01

A tissue digestion assay using a double separatory funnel procedure for the detection of Trichinella larvae in horse meat was validated for application in food safety programs and trade. The assay consisted of a pepsin-HCl digestion step to release larvae from muscle tissue and two sequential sedimentation steps in separatory funnels to recover and concentrate larvae for detection with a stereomicroscope. With defined critical control points, the assay was conducted within a quality assurance system compliant with International Organization for Standardization-International Electrotechnical Commission (ISO/IEC) 17025 guidelines. Samples used in the validation were obtained from horses experimentally infected with Trichinella spiralis to obtain a range of muscle larvae densities. One-, 5-, and 10-g samples of infected tissue were combined with 99, 95, and 90 g, respectively, of known negative horse tissue to create a 100-g sample for testing. Samples of 5 and 10 g were more likely to be positive than were 1-g samples when larval densities were less than three larvae per gram (lpg). This difference is important because ingested meat with 1 lpg is considered the threshold for clinical disease in humans. Using a 5-g sample size, all samples containing 1.3 to 2 lpg were detected, and 60 to 100% of samples with infected horse meat containing 0.1 to 0.7 lpg were detected. In this study, the double separatory funnel digestion assay was efficient and reliable for its intended use in food safety and trade. This procedure is the only digestion assay for Trichinella in horse meat that has been validated as consistent and effective at critical levels of sensitivity.

A High-Content Assay for Biosensor Validation and for Examining Stimuli that Affect Biosensor Activity.

Science.gov (United States)

Slattery, Scott D; Hahn, Klaus M

2014-12-01

Biosensors are valuable tools used to monitor many different protein behaviors in vivo. Demand for new biosensors is high, but their development and characterization can be difficult. During biosensor design, it is necessary to evaluate the effects of different biosensor structures on specificity, brightness, and fluorescence responses. By co-expressing the biosensor with upstream proteins that either stimulate or inhibit the activity reported by the biosensor, one can determine the difference between the biosensor's maximally activated and inactivated state, and examine response to specific proteins. We describe here a method for biosensor validation in a 96-well plate format using an automated microscope. This protocol produces dose-response curves, enables efficient examination of many parameters, and unlike cell suspension assays, allows visual inspection (e.g., for cell health and biosensor or regulator localization). Optimization of single-chain and dual-chain Rho GTPase biosensors is addressed, but the assay is applicable to any biosensor that can be expressed or otherwise loaded in adherent cells. The assay can also be used for purposes other than biosensor validation, using a well-characterized biosensor as a readout for effects of upstream molecules. Copyright © 2014 John Wiley & Sons, Inc.

A real-time polymerase chain reaction method for the identification of four commercially important salmon and trout species.

Science.gov (United States)

Feng, Junli; Wu, Zhigang; Xie, Xiao; Dai, Zhiyuan; Liu, Shasha

2017-01-01

A duplex quantitative real-time PCR (qPCR) assay was developed for rapid and accurate identification of four commercially important salmon and trout species (Oncorhynchus keta, Oncorhynchus nerka, Oncorhynchus mykiss, and Salmo salar) commonly used for production process of fish in China. The assays targeting the mitochondrial control region (CR) and 16S rRNA gene were able to simultaneously discriminate four target species and the family Salmonidae from processed as well as fresh fish. The qPCR efficiency of each reaction was calculated according to the standard curve, and the method was validated by amplification DNA extracted from single or artificial mixtures prepared with the reference salmon and trout species. Testing of 11 commercial salmon and trout products by the established qPCR assay demonstrated that it was really a useful and academic technique to identify four commercially important salmon and trout species.

A High-Content Live-Cell Viability Assay and Its Validation on a Diverse 12K Compound Screen.

Science.gov (United States)

Chiaravalli, Jeanne; Glickman, J Fraser

2017-08-01

We have developed a new high-content cytotoxicity assay using live cells, called "ImageTOX." We used a high-throughput fluorescence microscope system, image segmentation software, and the combination of Hoechst 33342 and SYTO 17 to simultaneously score the relative size and the intensity of the nuclei, the nuclear membrane permeability, and the cell number in a 384-well microplate format. We then performed a screen of 12,668 diverse compounds and compared the results to a standard cytotoxicity assay. The ImageTOX assay identified similar sets of compounds to the standard cytotoxicity assay, while identifying more compounds having adverse effects on cell structure, earlier in treatment time. The ImageTOX assay uses inexpensive commercially available reagents and facilitates the use of live cells in toxicity screens. Furthermore, we show that we can measure the kinetic profile of compound toxicity in a high-content, high-throughput format, following the same set of cells over an extended period of time.

Intra-/inter-laboratory validation study on reactive oxygen species assay for chemical photosafety evaluation using two different solar simulators.

Science.gov (United States)

Onoue, Satomi; Hosoi, Kazuhiro; Toda, Tsuguto; Takagi, Hironori; Osaki, Naoto; Matsumoto, Yasuhiro; Kawakami, Satoru; Wakuri, Shinobu; Iwase, Yumiko; Yamamoto, Toshinobu; Nakamura, Kazuichi; Ohno, Yasuo; Kojima, Hajime

2014-06-01

A previous multi-center validation study demonstrated high transferability and reliability of reactive oxygen species (ROS) assay for photosafety evaluation. The present validation study was undertaken to verify further the applicability of different solar simulators and assay performance. In 7 participating laboratories, 2 standards and 42 coded chemicals, including 23 phototoxins and 19 non-phototoxic drugs/chemicals, were assessed by the ROS assay using two different solar simulators (Atlas Suntest CPS series, 3 labs; and Seric SXL-2500V2, 4 labs). Irradiation conditions could be optimized using quinine and sulisobenzone as positive and negative standards to offer consistent assay outcomes. In both solar simulators, the intra- and inter-day precisions (coefficient of variation; CV) for quinine were found to be below 10%. The inter-laboratory CV for quinine averaged 15.4% (Atlas Suntest CPS) and 13.2% (Seric SXL-2500V2) for singlet oxygen and 17.0% (Atlas Suntest CPS) and 7.1% (Seric SXL-2500V2) for superoxide, suggesting high inter-laboratory reproducibility even though different solar simulators were employed for the ROS assay. In the ROS assay on 42 coded chemicals, some chemicals (ca. 19-29%) were unevaluable because of limited solubility and spectral interference. Although several false positives appeared with positive predictivity of ca. 76-92% (Atlas Suntest CPS) and ca. 75-84% (Seric SXL-2500V2), there were no false negative predictions in both solar simulators. A multi-center validation study on the ROS assay demonstrated satisfactory transferability, accuracy, precision, and predictivity, as well as the availability of other solar simulators. Copyright © 2013 Elsevier Ltd. All rights reserved.

ICCS/ESCCA consensus guidelines to detect GPI-deficient cells in paroxysmal nocturnal hemoglobinuria (PNH) and related disorders part 4 - assay validation and quality assurance.

Science.gov (United States)

Oldaker, Teri; Whitby, Liam; Saber, Maryam; Holden, Jeannine; Wallace, Paul K; Litwin, Virginia

2018-01-01

Over the past six years, a diverse group of stakeholders have put forth recommendations regarding the analytical validation of flow cytometric methods and described in detail the differences between cell-based and traditional soluble analyte assay validations. This manuscript is based on these general recommendations as well as the published experience of experts in the area of PNH testing. The goal is to provide practical assay-specific guidelines for the validation of high-sensitivity flow cytometric PNH assays. Examples of the reports and validation data described herein are provided in Supporting Information. © 2017 International Clinical Cytometry Society. © 2017 International Clinical Cytometry Society.

Establishment and intra-/inter-laboratory validation of a standard protocol of reactive oxygen species assay for chemical photosafety evaluation.

Science.gov (United States)

Onoue, Satomi; Hosoi, Kazuhiro; Wakuri, Shinobu; Iwase, Yumiko; Yamamoto, Toshinobu; Matsuoka, Naoko; Nakamura, Kazuichi; Toda, Tsuguto; Takagi, Hironori; Osaki, Naoto; Matsumoto, Yasuhiro; Kawakami, Satoru; Seto, Yoshiki; Kato, Masashi; Yamada, Shizuo; Ohno, Yasuo; Kojima, Hajime

2013-11-01

A reactive oxygen species (ROS) assay was previously developed for photosafety evaluation of pharmaceuticals, and the present multi-center study aimed to establish and validate a standard protocol for ROS assay. In three participating laboratories, two standards and 42 coded chemicals, including 23 phototoxins and 19 nonphototoxic drugs/chemicals, were assessed by the ROS assay according to the standardized protocol. Most phototoxins tended to generate singlet oxygen and/or superoxide under UV-vis exposure, but nonphototoxic chemicals were less photoreactive. In the ROS assay on quinine (200 µm), a typical phototoxic drug, the intra- and inter-day precisions (coefficient of variation; CV) were found to be 1.5-7.4% and 1.7-9.3%, respectively. The inter-laboratory CV for quinine averaged 15.4% for singlet oxygen and 17.0% for superoxide. The ROS assay on 42 coded chemicals (200 µm) provided no false negative predictions upon previously defined criteria as compared with the in vitro/in vivo phototoxicity, although several false positives appeared. Outcomes from the validation study were indicative of satisfactory transferability, intra- and inter-laboratory variability, and predictive capacity of the ROS assay. Copyright © 2012 John Wiley & Sons, Ltd.

Evaluation of Two Commercial Enzyme-Linked Immunosorbent Assay Kits for the Detection of Human Circulating Metrnl.

Science.gov (United States)

Zheng, Si-Li; Li, Zhi-Yong; Zhang, Zheng; Wang, Dong-Sheng; Xu, Jian; Miao, Chao-Yu

2018-04-01

Metrnl is a newly discovered secreted protein with neurotrophic activity and metabolic effect, while in earlier studies its circulating level in human was not explored. We evaluated two commercial enzyme-linked immunosorbent assay kits (DY7867-05, R&D Systems and SK00478-02, Aviscera Bioscience) for the detection of human circulating Metrnl. The DY7867-05 kit showed superiority over the SK00478-02 kit since it generated better curve fitting degree, smaller variation among tests, higher inter-assay reproducibility and better specificity, and could effectively detect human Metrnl in six types of blood samples. Subsequent analysis was performed using the DY7867-05 kit. Sample storage conditions were investigated. No gender difference in circulating Metrnl levels was found, while people with newly diagnosed type 2 diabetes mellitus (T2DM) had significantly lower Metrnl levels compared to the healthy controls.

Validity of urinary monoamine assay sales under the "spot baseline urinary neurotransmitter testing marketing model".

Science.gov (United States)

Hinz, Marty; Stein, Alvin; Uncini, Thomas

2011-01-01

Spot baseline urinary monoamine assays have been used in medicine for over 50 years as a screening test for monoamine-secreting tumors, such as pheochromocytoma and carcinoid syndrome. In these disease states, when the result of a spot baseline monoamine assay is above the specific value set by the laboratory, it is an indication to obtain a 24-hour urine sample to make a definitive diagnosis. There are no defined applications where spot baseline urinary monoamine assays can be used to diagnose disease or other states directly. No peer-reviewed published original research exists which demonstrates that these assays are valid in the treatment of individual patients in the clinical setting. Since 2001, urinary monoamine assay sales have been promoted for numerous applications under the "spot baseline urinary neurotransmitter testing marketing model". There is no published peer-reviewed original research that defines the scientific foundation upon which the claims for these assays are made. On the contrary, several articles have been published that discredit various aspects of the model. To fill the void, this manuscript is a comprehensive review of the scientific foundation and claims put forth by laboratories selling urinary monoamine assays under the spot baseline urinary neurotransmitter testing marketing model.

Validated high-performance liquid chromatographic method for the standardisation of Ptychopetalum olacoides Benth., Olacaceae, commercial extracts

Directory of Open Access Journals (Sweden)

Renata Colombo

2010-10-01

Full Text Available Ptychopetalum olacoides Benth., Olacaceae, popularly known as marapuama or muirapuama or miriantã, is a species native to the Amazonian region of Brazil. Extracts of the bark of the plant have been used traditionally for its stimulating and aphrodisiac properties and currently commercialised by the herbal industry as constituents in a wide range of phytomedicines. Fractionation by open column chromatography followed by preparative HPLC-UV/PAD of the stem bark and of three commercial extracts of P. olacoides allowed the isolation of three components that were common to all extracts analysed, and these were identified by NMR to be vanillic acid, protocatechuic acid and theobromine. Vanillic acid, which has been proposed as a phytochemical marker for P. olacoides, was employed as an external standard in the development and validation of a rapid qualitative and quantitative HPLC assay for the analyte. The recoveries values of the developed method were 99.02% and the LOD and LOQ values were 0.033 and 0.11 mg.L-1, respectively. The described method may be applied to the standardisation of herbs, extracts or phytomedicines commercialised as marapuama.

Comparison of one commercial and two in-house TaqMan multiplex real-time PCR assays for detection of enteropathogenic, enterotoxigenic and enteroaggregative Escherichia coli.

Science.gov (United States)

Hahn, Andreas; Luetgehetmann, Marc; Landt, Olfert; Schwarz, Norbert Georg; Frickmann, Hagen

2017-11-01

Enteropathogenic, enterotoxigenic and enteroaggregative Escherichia coli (EPEC, ETEC, EAEC) are among the most frequent causes of diarrhoea during travel or on military deployments. Cost-efficient and reliable real-time multiplex PCR (mPCR) assays are desirable for surveillance or point prevalence studies in remote and resource-limited tropical settings. We compared one commercial PCR kit and two in-house assays without using a gold standard to estimate sensitivity and specificity of each assay. Residual materials from nucleic acid extractions of stool samples from two groups with presumably different prevalences and increased likelihood of being infected or colonised by diarrhoeagenic E. coli were included in the assessment. One group comprised samples from returnees from tropical deployments, the second group was of migrants and study participants from high-endemicity settings. Each sample was assessed with all of the PCR assays. Cycle threshold (Ct) values were descriptively compared. The calculated sensitivities for the commercial test vs. the in-house tests were for EPEC 0.84 vs. 0.89 and 0.96, for ETEC 0.83 vs. 0.76 and 0.61, and for EAEC 0.69 vs. 0.54 and 0.69. False positive results were rare - specificity was 0.94 and 0.97 for two EPEC tests and 1.0 for all other tests. Most positive samples had late Ct values corresponding to low quantities of pathogens. Discordant test results were associated with late Ct values. As commercial and in-house assays showed comparable results, in-house tests can be assumed to be safe while affording considerable savings, making them a valuable alternative for surveillance testing in resource-limited tropical areas. © 2017 John Wiley & Sons Ltd.

Evaluation and validation of a single-dilution potency assay based upon serology of vaccines containing diphtheria toxoid: statistical analysis

NARCIS (Netherlands)

Marsman FR; Akkermans AM; Hendriksen CFM; de Jong WH

1993-01-01

This document presents the results of a validation study to the use of a single dilution assay in potency testing of the diphtheria component of DPT-polio vaccines. Based on historical data of multi-dilution assays on 27 consecutive batches a simulation study was performed to test the actual

Evaluation of 4,4'-diaminodiphenyl ether in the rat comet assay: Part of the Japanese Center for the Validation of Alternative Methods (JaCVAM)-initiative international validation study of in vivo rat alkaline comet assay.

Science.gov (United States)

Priestley, Catherine C; Walker, Joanne S; O'Donovan, Michael R; Doherty, Ann T

2015-07-01

As a part of the Japanese Center for the Validation of Alternative Methods (JaCVAM)-initiative international validation study of the in vivo rat alkaline comet assay, 4,4'-diaminodiphenyl ether (DPE), a known rodent genotoxic carcinogen, was tested in this laboratory. Sprague Dawley rats (7-9 weeks of age) were given three oral doses of DPE, 24 and 21 h apart and liver or stomach sampled 3h after the final dose. Under the conditions of the test, no increases in DNA damage in liver and stomach were observed with DPE (up to 200 mg/kg/day). A dose-dependent decrease in DNA migration, compared to vehicle controls, was noted for DPE in rat stomach. Further analysis is required to elucidate fully whether this decrease is a consequence of the mode of action or due to the toxicity of DPE. What is perhaps surprising is the inability of the comet assay to detect a known rat genotoxic carcinogen in liver. Further investigation is needed to clarify whether this apparent lack of response results from limited tissue exposure or metabolic differences between species. This finding highlights a need for careful consideration of study design when evaluating assay performance as a measure of in vivo genotoxicity. Copyright © 2015 Elsevier B.V. All rights reserved.

Development of robotic plasma radiochemical assays for positron emission tomography

International Nuclear Information System (INIS)

Alexoff, D.L.; Shea, C.; Fowler, J.S.; Gatley, S.J.; Schlyer, D.J.

1995-01-01

A commercial laboratory robot system (Zymate PyTechnology II Laboratory Automation System; Zymark Corporation, Hopkinton, MA) was interfaced to standard and custom laboratory equipment and programmed to perform rapid radiochemical analyses for quantitative PET studies. A Zymark XP robot arm was used to carry out the determination of unchanged (parent) radiotracer in plasma using only solid phase extraction methods. Robotic throughput for the assay of parent radiotracer in plasma is 4--6 samples/hour depending on the radiotracer. Robotic assays of parent compound in plasma were validated for the radiotracers [ 11 C]Benztropine, [ 11 C]cocaine, [ 11 C]clorgyline, [ 11 C]deprenyl, [ 11 C]methadone, [ 11 C]methylphenidate, [ 11 C]raclorpride, and [ 11 C]SR46349B. A simple robot-assisted methods development strategy has been implemented to facilitate the automation of plasma assays of new radiotracers

Novel TaqMan real-time polymerase chain reaction assay for verifying the authenticity of meat and commercial meat products from game birds.

Science.gov (United States)

Rojas, María; González, Isabel; Pavón, Miguel Angel; Pegels, Nicolette; Lago, Adriana; Hernández, Pablo E; García, Teresa; Martín, Rosario

2010-06-01

Species-specific real-time polymerase chain reaction (PCR) assays using TaqMan probes have been developed for verifying the labeling of meat and commercial meat products from game birds, including quail, pheasant, partridge, guinea fowl, pigeon, Eurasian woodcock and song thrush. The method combines the use of species-specific primers and TaqMan probes that amplify small fragments (amplicons meat products from the target species demonstrated the suitability of the assay for the detection of the target DNAs.

Quantifying the foodscape: A systematic review and meta-analysis of the validity of commercially available business data

OpenAIRE

Lebel, Alexandre; Daepp, Madeleine I. G.; Block, Jason P.; Walker, Renée; Lalonde, Benoît; Kestens, Yan; Subramanian, S. V.

2017-01-01

This paper reviews studies of the validity of commercially available business (CAB) data on food establishments (?the foodscape?), offering a meta-analysis of characteristics associated with CAB quality and a case study evaluating the performance of commonly-used validity indicators describing the foodscape. Existing validation studies report a broad range in CAB data quality, although most studies conclude that CAB quality is ?moderate? to ?substantial?. We conclude that current studies may ...

Methodology for validating technical tools to assess customer Demand Response: Application to a commercial customer

International Nuclear Information System (INIS)

Alcazar-Ortega, Manuel; Escriva-Escriva, Guillermo; Segura-Heras, Isidoro

2011-01-01

The authors present a methodology, which is demonstrated with some applications to the commercial sector, in order to validate a Demand Response (DR) evaluation method previously developed and applied to a wide range of industrial and commercial segments, whose flexibility was evaluated by modeling. DR is playing a more and more important role in the framework of electricity systems management for the effective integration of other distributed energy resources. Consequently, customers must identify what they are using the energy for in order to use their flexible loads for management purposes. Modeling tools are used to predict the impact of flexibility on the behavior of customers, but this result needs to be validated since both customers and grid operators have to be confident in these flexibility predictions. An easy-to-use two-steps method to achieve this goal is presented in this paper.

High-throughput screening assay used in pharmacognosy: Selection, optimization and validation of methods of enzymatic inhibition by UV-visible spectrophotometry

Directory of Open Access Journals (Sweden)

Graciela Granados-Guzmán

2014-02-01

Full Text Available In research laboratories of both organic synthesis and extraction of natural products, every day a lot of products that can potentially introduce some biological activity are obtained. Therefore it is necessary to have in vitro assays, which provide reliable information for further evaluation in in vivo systems. From this point of view, in recent years has intensified the use of high-throughput screening assays. Such trials should be optimized and validated for accurate and precise results, i.e. reliable. The present review addresses the steps needed to develop and validate bioanalytical methods, emphasizing UV-Visible spectrophotometry as detection system. Particularly focuses on the selection of the method, the optimization to determine the best experimental conditions, validation, implementation of optimized and validated method to real samples, and finally maintenance and possible transfer it to a new laboratory.

Development and validation of a mass spectrometry-based assay for quantification of insulin-like factor 3 in human serum

DEFF Research Database (Denmark)

Albrethsen, Jakob; Frederiksen, Hanne; Andersson, Anna-Maria

2018-01-01

BACKGROUND: The circulating level of the peptide hormone insulin-like factor 3 (INSL3) is a promising diagnostic marker reflecting Leydig cell function in the male. Few commercial immunoassays of varying quality exist. Therefore, we decided to develop and validate a precise method for quantificat......BACKGROUND: The circulating level of the peptide hormone insulin-like factor 3 (INSL3) is a promising diagnostic marker reflecting Leydig cell function in the male. Few commercial immunoassays of varying quality exist. Therefore, we decided to develop and validate a precise method...

Validation of a UV Spectrometric Method for the Assay of Tolfenamic Acid in Organic Solvents

Directory of Open Access Journals (Sweden)

Sofia Ahmed

2015-01-01

Full Text Available The present study has been carried out to validate a UV spectrometric method for the assay of tolfenamic acid (TA in organic solvents. TA is insoluble in water; therefore, a total of thirteen commonly used organic solvents have been selected in which the drug is soluble. Fresh stock solutions of TA in each solvent in a concentration of 1 × 10−4 M (2.62 mg% were prepared for the assay. The method has been validated according to the guideline of International Conference on Harmonization and parameters like linearity, range, accuracy, precision, sensitivity, and robustness have been studied. Although the method was found to be efficient for the determination of TA in all solvents on the basis of statistical data 1-octanol, followed by ethanol and methanol, was found to be comparatively better than the other studied solvents. No change in the stock solution stability of TA has been observed in each solvent for 24 hours stored either at room (25±1°C or at refrigerated temperature (2–8°C. A shift in the absorption maxima has been observed for TA in various solvents indicating drug-solvent interactions. The studied method is simple, rapid, economical, accurate, and precise for the assay of TA in different organic solvents.

Commercial demand for energy: a disaggregated approach. [Model validation for 1970-1975; forecasting to 2000

Energy Technology Data Exchange (ETDEWEB)

Jackson, J.R.; Cohn, S.; Cope, J.; Johnson, W.S.

1978-04-01

This report describes the structure and forecasting accuracy of a disaggregated model of commercial energy use recently developed at Oak Ridge National Laboratory. The model forecasts annual commercial energy use by ten building types, five end uses, and four fuel types. Both economic (utilization rate, fuel choice, capital-energy substitution) and technological factors (equipment efficiency, thermal characteristics of buildings) are explicitly represented in the model. Model parameters are derived from engineering and econometric analysis. The model is then validated by simulating commercial energy use over the 1970--1975 time period. The model performs well both with respect to size of forecast error and ability to predict turning points. The model is then used to evaluate the energy-use implications of national commercial buildings standards based on the ASHRAE 90-75 recommendations. 10 figs., 12 tables, 14 refs.

Clinical validation of an epigenetic assay to predict negative histopathological results in repeat prostate biopsies.

Science.gov (United States)

Partin, Alan W; Van Neste, Leander; Klein, Eric A; Marks, Leonard S; Gee, Jason R; Troyer, Dean A; Rieger-Christ, Kimberly; Jones, J Stephen; Magi-Galluzzi, Cristina; Mangold, Leslie A; Trock, Bruce J; Lance, Raymond S; Bigley, Joseph W; Van Criekinge, Wim; Epstein, Jonathan I

2014-10-01

The DOCUMENT multicenter trial in the United States validated the performance of an epigenetic test as an independent predictor of prostate cancer risk to guide decision making for repeat biopsy. Confirming an increased negative predictive value could help avoid unnecessary repeat biopsies. We evaluated the archived, cancer negative prostate biopsy core tissue samples of 350 subjects from a total of 5 urological centers in the United States. All subjects underwent repeat biopsy within 24 months with a negative (controls) or positive (cases) histopathological result. Centralized blinded pathology evaluation of the 2 biopsy series was performed in all available subjects from each site. Biopsies were epigenetically profiled for GSTP1, APC and RASSF1 relative to the ACTB reference gene using quantitative methylation specific polymerase chain reaction. Predetermined analytical marker cutoffs were used to determine assay performance. Multivariate logistic regression was used to evaluate all risk factors. The epigenetic assay resulted in a negative predictive value of 88% (95% CI 85-91). In multivariate models correcting for age, prostate specific antigen, digital rectal examination, first biopsy histopathological characteristics and race the test proved to be the most significant independent predictor of patient outcome (OR 2.69, 95% CI 1.60-4.51). The DOCUMENT study validated that the epigenetic assay was a significant, independent predictor of prostate cancer detection in a repeat biopsy collected an average of 13 months after an initial negative result. Due to its 88% negative predictive value adding this epigenetic assay to other known risk factors may help decrease unnecessary repeat prostate biopsies. Copyright © 2014 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Comparison and validation of ELISA assays for plasma insulin-like growth factor-1 in the horse

Directory of Open Access Journals (Sweden)

Courtnay L. Baskerville

2017-03-01

Full Text Available Insulin-like growth factor-1 (IGF-1 plays several important physiological roles, and IGF-related pathways have been implicated in developmental osteochondral disease and endocrinopathic laminitis. This factor is also a downstream marker of growth hormone activity and its peptide mimetics. Unfortunately, previously used assays for measuring equine IGF-1 (radioimmunoassays and ELISAs are no longer commercially available, and many of the kits on the market give poor results when used on horse samples. The aim of the present study was to compare three different ELISA assays (two human and one horse-specific. Plasma samples from six Standardbreds, six ponies and six Andalusians were used. The human IGF-1 ELISA kit from Immunodiagnostic Systems (IDS proved to be the most accurate and precise of the three kits; the other two assays gave apparently much lower concentrations, with poor recovery of spiked recombinant human IGF-1 and unacceptably poor intra-assay coefficients of variation (CV. The IDS assay gave an intra-assay CV of 3.59 % and inter-assay CV of 7.31%. Mean percentage recovery of spiked IGF-1 was 88.82%, and linearity and dilutional parallelism were satisfied. The IGF-1 plasma concentrations were 123.21 ±8.24 ng/mL for Standardbreds, 124.95 ±3.69 ng/mL for Andalusians and 174.26 ±1.94 ng/mL for ponies. Therefore of the three assays assessed, the IGF-1 ELISA manufactured by IDS was the most suitable for use with equine plasma samples and may have many useful applications in several different research areas. However, caution should be used when comparing equine studies where different analytical techniques and assays may have been used to measure this growth factor.

Development and Validation of Protein Microarray Technology for Simultaneous Inflammatory Mediator Detection in Human Sera

Directory of Open Access Journals (Sweden)

Senthooran Selvarajah

2014-01-01

Full Text Available Biomarkers, including cytokines, can help in the diagnosis, prognosis, and prediction of treatment response across a wide range of disease settings. Consequently, the recent emergence of protein microarray technology, which is able to quantify a range of inflammatory mediators in a large number of samples simultaneously, has become highly desirable. However, the cost of commercial systems remains somewhat prohibitive. Here we show the development, validation, and implementation of an in-house microarray platform which enables the simultaneous quantitative analysis of multiple protein biomarkers. The accuracy and precision of the in-house microarray system were investigated according to the Food and Drug Administration (FDA guidelines for pharmacokinetic assay validation. The assay fell within these limits for all but the very low-abundant cytokines, such as interleukin- (IL- 10. Additionally, there were no significant differences between cytokine detection using our microarray system and the “gold standard” ELISA format. Crucially, future biomarker detection need not be limited to the 16 cytokines shown here but could be expanded as required. In conclusion, we detail a bespoke protein microarray system, utilizing well-validated ELISA reagents, that allows accurate, precise, and reproducible multiplexed biomarker quantification, comparable with commercial ELISA, and allowing customization beyond that of similar commercial microarrays.

Validation of Non-Invasive Waste Assay System (Gamma Box Counter) Performance at AECL Whiteshell Laboratories - 13136

International Nuclear Information System (INIS)

Attas, E.M.; Bialas, E.; Rhodes, M.J.

2013-01-01

Low-level radioactive waste (LLW) in solid form, resulting from decommissioning and operations activities at AECL's Whiteshell Laboratories (WL), is packaged in B-25 and B-1000 standard waste containers and characterized before it is shipped to an on-site interim storage facility, pending AECL decisions on long term management of its LLW. Assay of the waste packages before shipment contributes to an inventory of the interim storage facility and provides data to support acceptance at a future repository. A key characterization step is a gamma spectrometric measurement carried out under standard conditions using an automated, multi-detector Waste Assay System (WAS), purchased from Antech Corporation. A combination of ORTEC gamma acquisition software and custom software is used in this system to incorporate multiple measurements from two collimated high-resolution detectors. The software corrects the intensities of the gamma spectral lines for geometry and attenuation, and generates a table of calculated activities or limits of detection for a user-defined list of radioisotopes that may potentially be present. Validation of WAS performance was a prerequisite to routine operation. Documentation of the validation process provides assurance of the quality of the results produced, which may be needed one or two decades after they were generated. Aspects of the validation included setting up a quality control routine, measurements of standard point sources in reproducible positions, study of the gamma background, optimization of user-selectable software parameters, investigation of the effect of non-uniform distribution of materials and radionuclides, and comparison of results with measurements made using other gamma detector systems designed to assay bulk materials. The following key components of the validation process have been established. A daily quality control routine has been instituted, to verify stability of the gamma detector operation and the background levels

A solid phase radioimmunoassay for free triiodothyronine in serum: assay development and validation

International Nuclear Information System (INIS)

Liu Fangyan; Zhou Meiying; Yin Linxiang; Yang Jianzhong; Hua Chenglin

1999-01-01

A solid phase radioimmunoassay for free triiodothyronine in serum was developed based on double-antibody coated tubes. The method was turned out to be reliable with good reproducibility, higher sensitivity and easy performance. The measurable range of FT 3 in serum was 1.2 to 38 pmol/L. The mean coefficients of variation within and between assays were 1.79%∼3.18% and 4.72%∼9.31%, respectively. The FT 3 concentrations in euthyroid serum as determined by this method were 2.8 to 7.8 pmol/L. The FT 3 values determined by this new method correlated well with those measured by a commercial radioimmunoassay (r = 0.853)

Evaluation of a Chlamydia trachomatis-specific, commercial, real-time PCR for use with ocular swabs.

Science.gov (United States)

Pickering, Harry; Holland, Martin J; Last, Anna R; Burton, Matthew J; Burr, Sarah E

2018-02-20

Trachoma, the leading infectious cause of blindness worldwide, is caused by conjunctival Chlamydia trachomatis infection. Trachoma is diagnosed clinically by observation of conjunctival inflammation and/or scarring; however, there is evidence that monitoring C. trachomatis infection may be required for elimination programmes. There are many commercial and 'in-house' nucleic acid amplification tests for the detection of C. trachomatis DNA, but the majority have not been validated for use with ocular swabs. This study evaluated a commercial assay, the Fast-Track Vaginal swab kit, using conjunctival samples from trachoma-endemic areas. An objective, biostatistical-based method for binary classification of continuous PCR data was developed, to limit potential user-bias in diagnostic settings. The Fast-Track Vaginal swab assay was run on 210 ocular swab samples from Guinea-Bissau and Tanzania. Fit of individual amplification curves to exponential or sigmoid models, derivative and second derivative of the curves and final fluorescence value were examined for utility in thresholding for determining positivity. The results from the Fast-Track Vaginal swab assay were evaluated against a commercial test (Amplicor CT/NG) and a non-commercial test (in-house droplet digital PCR), both of whose performance has previously been evaluated. Significant evidence of exponential amplification (R 2  > 0.99) and final fluorescence > 0.15 were combined for thresholding. This objective approach identified a population of positive samples, however there were a subset of samples that amplified towards the end of the cycling protocol (at or later than 35 cycles), which were less clearly defined. The Fast-Track Vaginal swab assay showed good sensitivity against the commercial (95.71) and non-commercial (97.18) tests. Specificity was lower against both (90.00 and 96.55, respectively). This study defined a simple, automated protocol for binary classification of continuous, real-time q

Real-time PCR assays for hepatitis B virus DNA quantification may require two different targets.

Science.gov (United States)

Liu, Chao; Chang, Le; Jia, Tingting; Guo, Fei; Zhang, Lu; Ji, Huimin; Zhao, Junpeng; Wang, Lunan

2017-05-12

Quantification Hepatitis B virus (HBV) DNA plays a critical role in the management of chronic HBV infections. However, HBV is a DNA virus with high levels of genetic variation, and drug-resistant mutations have emerged with the use of antiviral drugs. If a mutation caused a sequence mismatched in the primer or probe of a commercial DNA quantification kit, this would lead to an underestimation of the viral load of the sample. The aim of this study was to determine whether commercial kits, which use only one pair of primers and a single probe, accurately quantify the HBV DNA levels and to develop an improved duplex real-time PCR assay. We developed a new duplex real-time PCR assay that used two pairs of primers and two probes based on the conserved S and C regions of the HBV genome. We performed HBV DNA quantitative detection of HBV samples and compared the results of our duplex real-time PCR assays with the COBAS TaqMan HBV Test version 2 and Daan real-time PCR assays. The target region of the discordant sample was amplified, sequenced, and validated using plasmid. The results of the duplex real-time PCR were in good accordance with the commercial COBAS TaqMan HBV Test version 2 and Daan real-time PCR assays. We showed that two samples from Chinese HBV infections underestimated viral loads when quantified by the Roche kit because of a mismatch between the viral sequence and the reverse primer of the Roche kit. The HBV DNA levels of six samples were undervalued by duplex real-time PCR assays of the C region because of mutations in the primer of C region. We developed a new duplex real-time PCR assay, and the results of this assay were similar to the results of commercial kits. The HBV DNA level could be undervalued when using the COBAS TaqMan HBV Test version 2 for Chinese HBV infections owing to a mismatch with the primer/probe. A duplex real-time PCR assay based on the S and C regions could solve this problem to some extent.

Development of a simple, low cost chronoamperometric assay for fructose based on a commercial graphite-nanoparticle modified screen-printed carbon electrode.

Science.gov (United States)

Nicholas, Phil; Pittson, Robin; Hart, John P

2018-02-15

This paper describes the development of a simple, low cost chronoamperometric assay, for the measurement of fructose, using a graphite-nanoparticle modified screen-printed electrode (SPCE-G-COOH). Cyclic voltammetry showed that the response of the SPCE-G-COOH enhanced the sensitivity and precision, towards the enzymatically generated ferrocyanide species, over a plain SPCE; therefore the former was employed in subsequent studies. Calibration studies were carried out using chronoamperometry with a 40µl mixture containing fructose, mediator and FDH, deposited onto the SPCE-G-COOH. The response was linear from 0.1mM to 1.0mM. A commercial fruit juice sample was analysed using the developed assay and the fructose concentration was calculated to be 477mM with a precision of 3.03% (n=5). Following fortification (477mM fructose) the mean recovery was found to be 97.12% with a coefficient of variation of 6.42% (n=5); consequently, the method holds promise for the analysis of commercial fruit juices. Copyright © 2017 Elsevier Ltd. All rights reserved.

High throughput analysis of red wine and grape phenolics-adaptation and validation of methyl cellulose precipitable tannin assay and modified Somers color assay to a rapid 96 well plate format.

Science.gov (United States)

Mercurio, Meagan D; Dambergs, Robert G; Herderich, Markus J; Smith, Paul A

2007-06-13

The methyl cellulose precipitable (MCP) tannin assay and a modified version of the Somers and Evans color assay were adapted to high-throughput (HTP) analysis. To improve efficiency of the MCP tannin assay, a miniaturized 1 mL format and a HTP format using 96 well plates were developed. The Somers color assay was modified to allow the standardization of pH and ethanol concentrations of wine samples in a simple one-step dilution with a buffer solution, thus removing inconsistencies between wine matrices prior to analysis and allowing for its adaptation to a HTP format. Validation studies showed that all new formats were efficient, and results were reproducible and analogous to the original formats.

Analytical validation of a new point-of-care assay for serum amyloid A in horses.

Science.gov (United States)

Schwartz, D; Pusterla, N; Jacobsen, S; Christopher, M M

2018-01-17

Serum amyloid A (SAA) is a major acute phase protein in horses. A new point-of-care (POC) test for SAA (Stablelab) is available, but studies evaluating its analytical accuracy are lacking. To evaluate the analytical performance of the SAA POC test by 1) determining linearity and precision, 2) comparing results in whole blood with those in serum or plasma, and 3) comparing POC results with those obtained using a previously validated turbidimetric immunoassay (TIA). Assay validation. Analytical validation of the POC test was done in accordance with American Society of Veterinary Clinical Pathology guidelines using residual equine serum/plasma and whole blood samples from the Clinical Pathology Laboratory at the University of California-Davis. A TIA was used as the reference method. We also evaluated the effect of haematocrit (HCT). The POC test was linear for SAA concentrations of up to at least 1000 μg/mL (r = 0.991). Intra-assay CVs were 13, 18 and 15% at high (782 μg/mL), intermediate (116 μg/mL) and low (64 μg/mL) concentrations. Inter-assay (inter-batch) CVs were 45, 14 and 15% at high (1372 μg/mL), intermediate (140 μg/mL) and low (56 μg/mL) concentrations. SAA results in whole blood were significantly lower than those in serum/plasma (P = 0.0002), but were positively correlated (r = 0.908) and not affected by HCT (P = 0.261); proportional negative bias was observed in samples with SAA>500 μg/mL. The difference between methods exceeded the 95% confidence interval of the combined imprecision of both methods (15%). Analytical validation could not be performed in whole blood, the sample most likely to be used stall side. The POC test has acceptable accuracy and precision in equine serum/plasma with SAA concentrations of up to at least 1000 μg/mL. Low inter-batch precision at high concentrations may affect serial measurements, and the use of the same test batch and sample type (serum/plasma or whole blood) is recommended. Comparison of results between the

Development and validation of bonded composite doubler repairs for commercial aircraft.

Energy Technology Data Exchange (ETDEWEB)

Roach, Dennis Patrick; Rackow, Kirk A.

2007-07-01

A typical aircraft can experience over 2,000 fatigue cycles (cabin pressurizations) and even greater flight hours in a single year. An unavoidable by-product of aircraft use is that crack, impact, and corrosion flaws develop throughout the aircraft's skin and substructure elements. Economic barriers to the purchase of new aircraft have placed even greater demands on efficient and safe repair methods. The use of bonded composite doublers offers the airframe manufacturers and aircraft maintenance facilities a cost effective method to safely extend the lives of their aircraft. Instead of riveting multiple steel or aluminum plates to facilitate an aircraft repair, it is now possible to bond a single Boron-Epoxy composite doubler to the damaged structure. The FAA's Airworthiness Assurance Center at Sandia National Labs (AANC), Boeing, and Federal Express completed a pilot program to validate and introduce composite doubler repair technology to the U.S. commercial aircraft industry. This project focused on repair of DC-10 fuselage structure and its primary goal was to demonstrate routine use of this repair technology using niche applications that streamline the design-to-installation process. As composite doubler repairs gradually appear in the commercial aircraft arena, successful flight operation data is being accumulated. These commercial aircraft repairs are not only demonstrating the engineering and economic advantages of composite doubler technology but they are also establishing the ability of commercial maintenance depots to safely adopt this repair technique. This report presents the array of engineering activities that were completed in order to make this technology available for widespread commercial aircraft use. Focused laboratory testing was conducted to compliment the field data and to address specific issues regarding damage tolerance and flaw growth in composite doubler repairs. Fatigue and strength tests were performed on a simulated wing

New generation pharmacogenomic tools: a SNP linkage disequilibrium Map, validated SNP assay resource, and high-throughput instrumentation system for large-scale genetic studies.

Science.gov (United States)

De La Vega, Francisco M; Dailey, David; Ziegle, Janet; Williams, Julie; Madden, Dawn; Gilbert, Dennis A

2002-06-01

Since public and private efforts announced the first draft of the human genome last year, researchers have reported great numbers of single nucleotide polymorphisms (SNPs). We believe that the availability of well-mapped, quality SNP markers constitutes the gateway to a revolution in genetics and personalized medicine that will lead to better diagnosis and treatment of common complex disorders. A new generation of tools and public SNP resources for pharmacogenomic and genetic studies--specifically for candidate-gene, candidate-region, and whole-genome association studies--will form part of the new scientific landscape. This will only be possible through the greater accessibility of SNP resources and superior high-throughput instrumentation-assay systems that enable affordable, highly productive large-scale genetic studies. We are contributing to this effort by developing a high-quality linkage disequilibrium SNP marker map and an accompanying set of ready-to-use, validated SNP assays across every gene in the human genome. This effort incorporates both the public sequence and SNP data sources, and Celera Genomics' human genome assembly and enormous resource ofphysically mapped SNPs (approximately 4,000,000 unique records). This article discusses our approach and methodology for designing the map, choosing quality SNPs, designing and validating these assays, and obtaining population frequency ofthe polymorphisms. We also discuss an advanced, high-performance SNP assay chemisty--a new generation of the TaqMan probe-based, 5' nuclease assay-and high-throughput instrumentation-software system for large-scale genotyping. We provide the new SNP map and validation information, validated SNP assays and reagents, and instrumentation systems as a novel resource for genetic discoveries.

Commercial Milk Enzyme-Linked Immunosorbent Assay (ELISA) Kit Reactivities to Purified Milk Proteins and Milk-Derived Ingredients.

Science.gov (United States)

Ivens, Katherine O; Baumert, Joseph L; Taylor, Steve L

2016-07-01

Numerous commercial enzyme-linked immunosorbent assay (ELISA) kits exist to quantitatively detect bovine milk residues in foods. Milk contains many proteins that can serve as ELISA targets including caseins (α-, β-, or κ-casein) and whey proteins (α-lactalbumin or β-lactoglobulin). Nine commercially-available milk ELISA kits were selected to compare the specificity and sensitivity with 5 purified milk proteins and 3 milk-derived ingredients. All of the milk kits were capable of quantifying nonfat dry milk (NFDM), but did not necessarily detect all individual protein fractions. While milk-derived ingredients were detected by the kits, their quantitation may be inaccurate due to the use of different calibrators, reference materials, and antibodies in kit development. The establishment of a standard reference material for the calibration of milk ELISA kits is increasingly important. The appropriate selection and understanding of milk ELISA kits for food analysis is critical to accurate quantification of milk residues and informed risk management decisions. © 2016 Institute of Food Technologists®

Toward an international standard for PCR-based detection of Escherichia coli O157 - Part 1. Assay development and multi-center validation

DEFF Research Database (Denmark)

Abdulmawjood, A.; Bulte, M.; Cook, N.

2003-01-01

As part of a major European research project, a diagnostic PCR assay, including an internal amplification control, was developed and validated in a collaborative trial for the detection of Escherichia coli O157. The assay is based on amplification of sequences of the rJbE O157 gene. The collabora...

Quantifying the foodscape: A systematic review and meta-analysis of the validity of commercially available business data

Science.gov (United States)

Lebel, Alexandre; Daepp, Madeleine I. G.; Block, Jason P.; Walker, Renée; Lalonde, Benoît; Kestens, Yan; Subramanian, S. V.

2017-01-01

This paper reviews studies of the validity of commercially available business (CAB) data on food establishments (“the foodscape”), offering a meta-analysis of characteristics associated with CAB quality and a case study evaluating the performance of commonly-used validity indicators describing the foodscape. Existing validation studies report a broad range in CAB data quality, although most studies conclude that CAB quality is “moderate” to “substantial”. We conclude that current studies may underestimate the quality of CAB data. We recommend that future validation studies use density-adjusted and exposure measures to offer a more meaningful characterization of the relationship of data error with spatial exposure. PMID:28358819

Measurement of alpha-fetoprotein in maternal serum: three commercial radioimmunoassay kits and two non-commercial radioimmunoassays compared

International Nuclear Information System (INIS)

Forest, J.C.; Verreault, F.; Pouliot, M.

1982-01-01

We evaluated three commercial radioimmunoassay kits (Amersham, Dainabot, Clinical Assays) and two non-commercial methods for determining alpha-fetoprotein in maternal serum during pregnancy. All five procedures were found to be acceptable with respect to practicability, sensitivity, linearity, and precision. Similar results were obtained with Dainabot, Clinical Assays, and the two non-commercial methods, but the Amersham method revealed a proportional error, results being about 20% lower than those by the other methods. Use of the international unit system is suggested for reporting results for AFP, to facilitate comparison between methods and laboratories

Evaluation of Commercial Diagnostic Assays for the Specific Detection of Avian Influenza A (H7N9) Virus RNA Using a Quality-Control Panel and Clinical Specimens in China

Science.gov (United States)

Chen, Suhong; Wang, Dayan; Li, Changgui; Wu, Xing; Li, Lili; Bai, Dongting; Zhang, Chuntao; Wang, Junzhi

2015-01-01

A novel avian influenza A H7N9-subtype virus emerged in China in 2013 and threatened global public health. Commercial kits that specifically detect avian influenza A (H7N9) virus RNA are urgently required to prepare for the emergence and potential pandemic of this novel influenza virus. The safety and effectiveness of three commercial molecular diagnostic assays were evaluated using a quality-control panel and clinical specimens collected from over 90 patients with confirmed avian influenza A (H7N9) virus infections. The analytical performance evaluation showed that diverse influenza H7N9 viruses can be detected with high within- and between-lot reproducibility and without cross-reactivity to other influenza viruses (H1N1 pdm09, seasonal H1N1, H3N2, H5N1 and influenza B). The detection limit of all the commercial assays was 2.83 Log10 copies/μl [0.7 Log10TCID50/mL of avian influenza A (H7N9) virus strain A/Zhejiang/DTID-ZJU01/2013], which is comparable to the method recommended by the World Health Organization (WHO). In addition, using a WHO-Chinese National Influenza Center (CNIC) method as a reference for clinical evaluation, positive agreement of more than 98% was determined for all of the commercial kits, while negative agreement of more than 99% was observed. In conclusion, our findings provide comprehensive evidence for the high performance of three commercial diagnostic assays and suggest the application of these assays as rapid and effective diagnostic tools for avian influenza A (H7N9) virus in the routine clinical practice of medical laboratories. PMID:26361351

Validation and Optimization of an Ex Vivo Assay of Intestinal Mucosal Biopsies in Crohn's Disease

DEFF Research Database (Denmark)

Vadstrup, Kasper; Galsgaard, Elisabeth Douglas; Gerwien, Jens

2016-01-01

human explant method to test drug candidates and pathophysiological conditions in CD intestinal biopsies. Mucosal biopsies from 27 CD patients and 6 healthy individuals were collected to validate an explant assay test where the polarized tissue was cultured on a novel metal mesh disk, slightly immersed...

A validated HPLC-MS/MS assay for quantifying unstable pharmacologically active metabolites of clopidogrel in human plasma: application to a clinical pharmacokinetic study.

Science.gov (United States)

Furlong, Michael T; Savant, Ishani; Yuan, Moucun; Scott, Laura; Mylott, William; Mariannino, Thomas; Kadiyala, Pathanjali; Roongta, Vikram; Arnold, Mark E

2013-05-01

Clopidogrel is prescribed for the treatment of Acute Coronary Syndrome and recent myocardial infarction, recent stroke, or established peripheral arterial disease. A sensitive and reliable high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) assay was developed and validated to enable reliable quantification of four diastereomeric and chemically reactive thiol metabolites, two of which are pharmacologically active, in human plasma. The metabolites were stabilized by alkylation of their reactive thiol moieties with 2-bromo-3'-methoxyacetophenone (MPB). Following organic solvent mediated-protein precipitation in a 96-well plate format, chromatographic separation was achieved by gradient elution on an Ascentis Express RP-amide column. Chromatographic conditions were optimized to ensure separation of the four derivatized active metabolites. Derivatized metabolites and stable isotope-labeled internal standards were detected by positive ion electrospray tandem mass spectrometry. The HPLC-MS/MS assay was validated over concentration ranges of 0.125-125 ng/mL for metabolites H1-H3 and 0.101-101 ng/mL for H4. Intra- and inter-assay precision values for replicate quality control samples were within 14.3% for all analytes during the assay validation. Mean quality control accuracy values were within ±6.3% of nominal values for all analytes. Assay recoveries were high (>79%). The four derivatized analytes were stable in human blood for at least 2 h at room temperature and on ice. The analytes were also stable in human plasma for at least 25 h at room temperature, 372 days at -20 °C and -70 °C, and following at least five freeze-thaw cycles. The validated assay was successfully applied to the quantification of all four thiol metabolites in human plasma in support of a human pharmacokinetic study. Copyright © 2013 Elsevier B.V. All rights reserved.

GPM ground validation via commercial cellular networks: an exploratory approach

Science.gov (United States)

Rios Gaona, Manuel Felipe; Overeem, Aart; Leijnse, Hidde; Brasjen, Noud; Uijlenhoet, Remko

2016-04-01

The suitability of commercial microwave link networks for ground validation of GPM (Global Precipitation Measurement) data is evaluated here. Two state-of-the-art rainfall products are compared over the land surface of the Netherlands for a period of 7 months, i.e., rainfall maps from commercial cellular communication networks and Integrated Multi-satellite Retrievals for GPM (IMERG). Commercial microwave link networks are nowadays the core component in telecommunications worldwide. Rainfall rates can be retrieved from measurements of attenuation between transmitting and receiving antennas. If adequately set up, these networks enable rainfall monitoring tens of meters above the ground at high spatiotemporal resolutions (temporal sampling of seconds to tens of minutes, and spatial sampling of hundreds of meters to tens of kilometers). The GPM mission is the successor of TRMM (Tropical Rainfall Measurement Mission). For two years now, IMERG offers rainfall estimates across the globe (180°W - 180°E and 60°N - 60°S) at spatiotemporal resolutions of 0.1° x 0.1° every 30 min. These two data sets are compared against a Dutch gauge-adjusted radar data set, considered to be the ground truth given its accuracy, spatiotemporal resolution and availability. The suitability of microwave link networks in satellite rainfall evaluation is of special interest, given the independent character of this technique, its high spatiotemporal resolutions and availability. These are valuable assets for water management and modeling of floods, landslides, and weather extremes; especially in places where rain gauge networks are scarce or poorly maintained, or where weather radar networks are too expensive to acquire and/or maintain.

Validation of an optical surface plasmon resonance biosensor assay for screening (fluoro)quinolones in egg, fish and poultry

NARCIS (Netherlands)

Huet, A.C.; Charlier, C.; Weigel, S.; Benrejeb Godefroy, S.; Delahaut, P.

2009-01-01

A surface plasmon resonance biosensor immunoassay has been developed for multi-residue determination of 13 (fluoro)quinolone antibiotics in poultry meat, eggs and fish. The following performance characteristics were determined according to the guidelines laid down for screening assay validation in

Validation of a commercially available indirect ELISA using a nucleocapside recombinant protein for detection of Schmallenberg virus antibodies.

Directory of Open Access Journals (Sweden)

Emmanuel Bréard

Full Text Available A newly developed Enzym Like Immuno Sorbant Assay (ELISA based on the recombinant nucleocapsid protein (N of Schmallenberg virus (SBV was evaluated and validated for the detection of SBV-specific IgG antibodies in ruminant sera by three European Reference Laboratories. Validation data sets derived from sheep, goat and bovine sera collected in France and Germany (n = 1515 in 2011 and 2012 were categorized according to the results of a virus neutralization test (VNT or an indirect immuno-fluorescence assay (IFA. The specificity was evaluated with 1364 sera from sheep, goat and bovine collected in France and Belgium before 2009. Overall agreement between VNT and ELISA was 98.9% and 98.3% between VNT and IFA, indicating a very good concordance between the different techniques. Although cross-reactions with other Orthobunyavirus from the Simbu serogroup viruses might occur, it is a highly sensitive, specific and robust ELISA-test validated to detect anti-SBV antibodies. This test can be applied for SBV sero-diagnostics and disease-surveillance studies in ruminant species in Europe.

Development and validation of a real-time PCR assay for the detection of anguillid herpesvirus 1.

Science.gov (United States)

van Beurden, S J; Voorbergen-Laarman, M A; Roozenburg, I; van Tellingen, J; Haenen, O L M; Engelsma, M Y

2016-01-01

Anguillid herpesvirus 1 (AngHV1) causes a haemorrhagic disease with increased mortality in wild and farmed European eel, Anguilla anguilla (L.) and Japanese eel Anguilla japonica, Temminck & Schlegel). Detection of AngHV1 is currently based on virus isolation in cell culture, antibody-based typing assays or conventional PCR. We developed, optimized and concisely validated a diagnostic TaqMan probe based real-time PCR assay for the detection of AngHV1. The primers and probe target AngHV1 open reading frame 57, encoding the capsid protease and scaffold protein. Compared to conventional PCR, the developed real-time PCR is faster, less labour-intensive and has a reduced risk of cross-contamination. The real-time PCR assay was shown to be analytically sensitive and specific and has a high repeatability, efficiency and r(2) -value. The diagnostic performance of the assay was determined by testing 10% w/v organ suspensions and virus cultures from wild and farmed European eels from the Netherlands by conventional and real-time PCR. The developed real-time PCR assay is a useful tool for the rapid and sensitive detection of AngHV1 in 10% w/v organ suspensions from wild and farmed European eels. © 2015 John Wiley & Sons Ltd.

Phytochemical Assays of Commercial Botanical Dietary Supplements

Directory of Open Access Journals (Sweden)

Robert Krochmal

2004-01-01

Full Text Available The growing popularity of botanical dietary supplements (BDS has been accompanied by concerns regarding the quality of commercial products. Health care providers, in particular, have an interest in knowing about product quality, in view of the issues related to herb-drug interactions and potential side effects. This study assessed whether commercial formulations of saw palmetto, kava kava, echinacea, ginseng and St. John's wort had consistent labeling and whether quantities of marker compounds agreed with the amounts stated on the label. We purchased six bottles each of two lots of supplements from nine manufacturers and analyzed the contents using established commercial methodologies at an independent laboratory. Product labels were found to vary in the information provided, such as serving recommendations and information about the herb itself (species, part of the plant, marker compound, etc. With regard to marker compound content, little variability was observed between different lots of the same brand, while the content did vary widely between brands (e.g. total phenolic compounds in Echinacea ranged from 3.9–15.3 mg per serving; total ginsenosides in ginseng ranged from 5.3–18.2 mg per serving. Further, the amounts recommended for daily use also differed between brands, increasing the potential range of a consumer's daily dose. Echinacea and ginseng were the most variable, while St. John's wort and saw palmetto were the least variable. This study highlights some of the key issues in the botanical supplement market, including the importance of standardized manufacturing practices and reliable labeling information. In addition, health care providers should keep themselves informed regarding product quality in order to be able to appropriately advise patients utilizing both conventional and herbal medicines.

Phytochemical Assays of Commercial Botanical Dietary Supplements

Science.gov (United States)

2004-01-01

The growing popularity of botanical dietary supplements (BDS) has been accompanied by concerns regarding the quality of commercial products. Health care providers, in particular, have an interest in knowing about product quality, in view of the issues related to herb-drug interactions and potential side effects. This study assessed whether commercial formulations of saw palmetto, kava kava, echinacea, ginseng and St. John's wort had consistent labeling and whether quantities of marker compounds agreed with the amounts stated on the label. We purchased six bottles each of two lots of supplements from nine manufacturers and analyzed the contents using established commercial methodologies at an independent laboratory. Product labels were found to vary in the information provided, such as serving recommendations and information about the herb itself (species, part of the plant, marker compound, etc.) With regard to marker compound content, little variability was observed between different lots of the same brand, while the content did vary widely between brands (e.g. total phenolic compounds in Echinacea ranged from 3.9–15.3 mg per serving; total ginsenosides in ginseng ranged from 5.3–18.2 mg per serving). Further, the amounts recommended for daily use also differed between brands, increasing the potential range of a consumer's daily dose. Echinacea and ginseng were the most variable, while St. John's wort and saw palmetto were the least variable. This study highlights some of the key issues in the botanical supplement market, including the importance of standardized manufacturing practices and reliable labeling information. In addition, health care providers should keep themselves informed regarding product quality in order to be able to appropriately advise patients utilizing both conventional and herbal medicines. PMID:15841264

Molecular identification of python species: development and validation of a novel assay for forensic investigations.

Science.gov (United States)

Ciavaglia, Sherryn A; Tobe, Shanan S; Donnellan, Stephen C; Henry, Julianne M; Linacre, Adrian M T

2015-05-01

Python snake species are often encountered in illegal activities and the question of species identity can be pertinent to such criminal investigations. Morphological identification of species of pythons can be confounded by many issues and molecular examination by DNA analysis can provide an alternative and objective means of identification. Our paper reports on the development and validation of a PCR primer pair that amplifies a segment of the mitochondrial cytochrome b gene that has been suggested previously as a good candidate locus for differentiating python species. We used this DNA region to perform species identification of pythons, even when the template DNA was of poor quality, as might be the case with forensic evidentiary items. Validation tests are presented to demonstrate the characteristics of the assay. Tests involved the cross-species amplification of this marker in non-target species, minimum amount of DNA template required, effects of degradation on product amplification and a blind trial to simulate a casework scenario that provided 100% correct identity. Our results demonstrate that this assay performs reliably and robustly on pythons and can be applied directly to forensic investigations where the presence of a species of python is in question. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

OpenComet: An automated tool for comet assay image analysis

Directory of Open Access Journals (Sweden)

Benjamin M. Gyori

2014-01-01

Full Text Available Reactive species such as free radicals are constantly generated in vivo and DNA is the most important target of oxidative stress. Oxidative DNA damage is used as a predictive biomarker to monitor the risk of development of many diseases. The comet assay is widely used for measuring oxidative DNA damage at a single cell level. The analysis of comet assay output images, however, poses considerable challenges. Commercial software is costly and restrictive, while free software generally requires laborious manual tagging of cells. This paper presents OpenComet, an open-source software tool providing automated analysis of comet assay images. It uses a novel and robust method for finding comets based on geometric shape attributes and segmenting the comet heads through image intensity profile analysis. Due to automation, OpenComet is more accurate, less prone to human bias, and faster than manual analysis. A live analysis functionality also allows users to analyze images captured directly from a microscope. We have validated OpenComet on both alkaline and neutral comet assay images as well as sample images from existing software packages. Our results show that OpenComet achieves high accuracy with significantly reduced analysis time.

An Improved Neutral a-Glucosidase Assay for Assessment of Epididymal Function—Validation and Comparison to the WHO Method

Directory of Open Access Journals (Sweden)

Frank Eertmans

2014-01-01

Full Text Available Neutral a-glucosidase (NAG activity in human seminal plasma is an important indicator for epididymis functionality. In the present study, the classic World Health Organization (WHO method has been adapted to enhance assay robustness. Changes include modified enzyme reaction buffer composition and usage of an alternative enzyme inhibitor for background correction (glucose instead of castanospermine. Both methods have been tested in parallel on 144 semen samples, obtained from 94 patients/donors and 50 vasectomized men (negative control, respectively. Passing-Bablok regression analysis demonstrated equal assay performance. In terms of assay validation, analytical specificity, detection limit, measuring range, precision, and cut-off values have been calculated. These data confirm that the adapted method is a reliable, improved tool for NAG analysis in human semen.

A practical approach for the validation and clinical implementation of a high-sensitivity cardiac troponin I assay across a North American city

Directory of Open Access Journals (Sweden)

Peter A. Kavsak

2015-04-01

Full Text Available Objectives: Despite several publications on the analytical performance of high-sensitivity cardiac troponin (hs-cTn assays, there has been little information on how laboratories should validate and implement these assays into clinical service. Our study provides a practical approach for the validation and implementation of a hs-cTn assay across a large North American City. Design and methods: Validation for the Abbott ARCHITECT hs-cTnI assay (across 5 analyzers consisted of verification of limit of blank (LoB, precision (i.e., coefficient of variation; CV testing at the reported limit of detection (LoD and within and outside the 99th percentile, linearity testing, cTnI versus hs-cTnI patient comparison within and between analyzers (Passing and Bablok and non-parametric analyses. Education, clinical communications, and memorandums were issued in advance to inform all staff across the city as well as a selected reminder the day before live-date to important users. All hospitals switched to the hs-cTnI assay concurrently (the contemporary cTnI assay removed with laboratory staff instructed to repeat samples previously measured with the contemporary cTnI assay with the hs-cTnI assay only by physician request. Results: Across the 5 analyzers and 6 reagent packs the overall LoB was 0.6 ng/L (n=60 with a CV of 33% at an overall mean of 1.2 ng/L (n=60; reported LoD=1.0 ng/L, with linearity demonstrated from 45,005 ng/L to 1.1 ng/L. Precision testing with a normal patient-pool QC material (mean range across 5 analyzers was 3.9–4.4 ng/L yielded a range of CVs from 7% to 10% (within-run and CVs from 7% to 18% (between-run with the high patient-pool QC material (mean range across 5 analyzers was 29.6–36.3 ng/L yielding a range of CVs from 2% to 5% (within-run and CVs from 4% to 8% (between-run. There was agreement between hs-cTnI versus cTnI with the patient samples (slope ranges: 0.89–1.03; intercept ranges: 1.9–3

Comparative analysis and validation of the malachite green assay for the high throughput biochemical characterization of terpene synthases.

Science.gov (United States)

Vardakou, Maria; Salmon, Melissa; Faraldos, Juan A; O'Maille, Paul E

2014-01-01

Terpenes are the largest group of natural products with important and diverse biological roles, while of tremendous economic value as fragrances, flavours and pharmaceutical agents. Class-I terpene synthases (TPSs), the dominant type of TPS enzymes, catalyze the conversion of prenyl diphosphates to often structurally diverse bioactive terpene hydrocarbons, and inorganic pyrophosphate (PPi). To measure their kinetic properties, current bio-analytical methods typically rely on the direct detection of hydrocarbon products by radioactivity measurements or gas chromatography-mass spectrometry (GC-MS). In this study we employed an established, rapid colorimetric assay, the pyrophosphate/malachite green assay (MG), as an alternative means for the biochemical characterization of class I TPSs activity.•We describe the adaptation of the MG assay for turnover and catalytic efficiency measurements of TPSs.•We validate the method by direct comparison with established assays. The agreement of k cat/K M among methods makes this adaptation optimal for rapid evaluation of TPSs.•We demonstrate the application of the MG assay for the high-throughput screening of TPS gene libraries.

Development and validation of the AmpFℓSTR® Identifiler® Direct PCR Amplification Kit: a multiplex assay for the direct amplification of single-source samples.

Science.gov (United States)

Wang, Dennis Y; Chang, Chien-Wei; Lagacé, Robert E; Oldroyd, Nicola J; Hennessy, Lori K

2011-07-01

The AmpFℓSTR(®) Identifiler(®) Direct PCR Amplification Kit is a new short tandem repeat multiplex assay optimized to allow the direct amplification of single-source blood and buccal samples on FTA(®) card without the need for sample purification and quantification. This multiplex assay has been validated according to the FBI/National Standards and SWGDAM guidelines. Validation results revealed that slight variations in primer concentration, master mix component concentration, and thermal cycling parameters did not affect the performance of the chemistry. The assay's sensitivity was demonstrated by amplifying known amounts of white blood cells spotted onto FTA(®) cards, and the assay's specificity was verified by establishing minimal cross-reactivity with nonhuman DNA. No effect on the age of the sample stored on the FTA(®) substrate was observed and full concordance was established in the population study. These findings of the validation study support the use of the Identifiler(®) Direct Kit for forensic standards and database samples genotyping. © 2011 American Academy of Forensic Sciences.

Development and validation of quantitative PCR assays to measure cytokine transcript levels in the Florida manatee (Trichechus manatus latirostris)

Science.gov (United States)

Ferrante, Jason; Hunter, Margaret; Wellehan, James F.X.

2018-01-01

Cytokines have important roles in the mammalian response to viral and bacterial infections, trauma, and wound healing. Because of early cytokine production after physiologic stresses, the regulation of messenger RNA (mRNA) transcripts can be used to assess immunologic responses before changes in protein production. To detect and assess early immune changes in endangered Florida manatees (Trichechus manatus latirostris), we developed and validated a panel of quantitative PCR assays to measure mRNA transcription levels for the cytokines interferon (IFN)-γ; interleukin (IL)-2, -6, and -10; tumor necrosis factor-α, and the housekeeping genes glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and β-actin (reference genes). Assays were successfully validated using blood samples from free-ranging, apparently healthy manatees from the east and west coasts of central Florida. No cytokine or housekeeping gene transcription levels were significantly different among age classes or sexes. However, the transcription levels for GAPDH, IL-2, IL-6, and IFN-γ were significantly higher (Puse as a reference gene in future studies. Our assays can aid in the investigation of manatee immune response to physical trauma and novel or ongoing environmental stressors.

The local lymph node assay and the assessment of relative potency: status of validation.

Science.gov (United States)

Basketter, David A; Gerberick, Frank; Kimber, Ian

2007-08-01

For the prediction of skin sensitization potential, the local lymph node assay (LLNA) is a fully validated alternative to guinea-pig tests. More recently, information from LLNA dose-response analyses has been used to assess the relative potency of skin sensitizing chemicals. These data are then deployed for risk assessment and risk management. In this commentary, the utility and validity of these relative potency measurements are reviewed. It is concluded that the LLNA does provide a valuable assessment of relative sensitizing potency in the form of the estimated concentration of a chemical required to produce a threefold stimulation of draining lymph node cell proliferation compared with concurrent controls (EC3 value) and that all reasonable validation requirements have been addressed successfully. EC3 measurements are reproducible in both intra- and interlaboratory evaluations and are stable over time. It has been shown also, by several independent groups, that EC3 values correlate closely with data on relative human skin sensitization potency. Consequently, the recommendation made here is that LLNA EC3 measurements should now be regarded as a validated method for the determination of the relative potency of skin sensitizing chemicals, a conclusion that has already been reached by a number of independent expert groups.

Development and validation of cell-based luciferase reporter gene assays for measuring neutralizing anti-drug antibodies against interferon beta

DEFF Research Database (Denmark)

Hermanrud, Christina; Ryner, Malin; Luft, Thomas

2016-01-01

a normal distribution for the majority of runs, allowing a parametric approach for cut-point calculation to be used, where NAb positive samples could be identified with 95% confidence. An analysis of means and variances indicated that a floating cut-point should be used for all assays. The assays......Neutralizing anti-drug antibodies (NAbs) against therapeutic interferon beta (IFNβ) in people with multiple sclerosis (MS) are measured with cell-based bioassays. The aim of this study was to redevelop and validate two luciferase reporter-gene bioassays, LUC and iLite, using a cut-point approach...... to identify NAb positive samples. Such an approach is favored by the pharmaceutical industry and governmental regulatory agencies as it has a clear statistical basis and overcomes the limitations of the current assays based on the Kawade principle. The work was conducted following the latest assay guidelines...

Bench-top validation testing of selected immunological and molecular Renibacterium salmoninarum diagnostic assays by comparison with quantitative bacteriological culture

Science.gov (United States)

Elliott, D.G.; Applegate, L.J.; Murray, A.L.; Purcell, M.K.; McKibben, C.L.

2013-01-01

No gold standard assay exhibiting error-free classification of results has been identified for detection of Renibacterium salmoninarum, the causative agent of salmonid bacterial kidney disease. Validation of diagnostic assays for R. salmoninarum has been hindered by its unique characteristics and biology, and difficulties in locating suitable populations of reference test animals. Infection status of fish in test populations is often unknown, and it is commonly assumed that the assay yielding the most positive results has the highest diagnostic accuracy, without consideration of misclassification of results. In this research, quantification of R. salmoninarum in samples by bacteriological culture provided a standardized measure of viable bacteria to evaluate analytical performance characteristics (sensitivity, specificity and repeatability) of non-culture assays in three matrices (phosphate-buffered saline, ovarian fluid and kidney tissue). Non-culture assays included polyclonal enzyme-linked immunosorbent assay (ELISA), direct smear fluorescent antibody technique (FAT), membrane-filtration FAT, nested polymerase chain reaction (nested PCR) and three real-time quantitative PCR assays. Injection challenge of specific pathogen-free Chinook salmon, Oncorhynchus tshawytscha (Walbaum), with R. salmoninarum was used to estimate diagnostic sensitivity and specificity. Results did not identify a single assay demonstrating the highest analytical and diagnostic performance characteristics, but revealed strengths and weaknesses of each test.

Evaluation of a commercially available enzyme-linked immunosorbent assay for the diagnosis of canine sarcoptic mange.

Science.gov (United States)

Curtis, C F

2001-02-24

This study was designed to assess the accuracy of a commercial enzyme-linked immunosorbent assay for the diagnosis of canine scabies. Serum samples from 37 dogs were examined blind; 12 had sarcoptic mange confirmed by the identification of mites in skin scrapings, 12 were atopic (with positive intradermal reactions to one or more aeroallergens, including Dermatophagoides farinae), and 13 were healthy dogs with no history of skin disease. Optical density values of more than 0.16 were considered positive, 0.145 to 0.16 were considered questionable and less than 0.145 were considered negative. Ten of the 12 dogs with scabies were positive, all 12 atopic dogs were negative, and 11 of the 13 healthy dogs were negative and two were questionable.

An immunohistochemical and fluorescence in situ hybridization-based comparison between the Oracle HER2 Bond Immunohistochemical System, Dako HercepTest, and Vysis PathVysion HER2 FISH using both commercially validated and modified ASCO/CAP and United Kingdom HER2 IHC scoring guidelines.

LENUS (Irish Health Repository)

O'Grady, Anthony

2010-12-01

Immunohistochemistry (IHC) is used as the frontline assay to determine HER2 status in invasive breast cancer patients. The aim of the study was to compare the performance of the Leica Oracle HER2 Bond IHC System (Oracle) with the current most readily accepted Dako HercepTest (HercepTest), using both commercially validated and modified ASCO\\/CAP and UK HER2 IHC scoring guidelines. A total of 445 breast cancer samples from 3 international clinical HER2 referral centers were stained with the 2 test systems and scored in a blinded fashion by experienced pathologists. The overall agreement between the 2 tests in a 3×3 (negative, equivocal and positive) analysis shows a concordance of 86.7% and 86.3%, respectively when analyzed using commercially validated and modified ASCO\\/CAP and UK HER2 IHC scoring guidelines. There is a good concordance between the Oracle and the HercepTest. The advantages of a complete fully automated test such as the Oracle include standardization of key analytical factors and improved turn around time. The implementation of the modified ASCO\\/CAP and UK HER2 IHC scoring guidelines has minimal effect on either assay interpretation, showing that Oracle can be used as a methodology for accurately determining HER2 IHC status in formalin fixed, paraffin-embedded breast cancer tissue.

An immunohistochemical and fluorescence in situ hybridization-based comparison between the Oracle HER2 Bond Immunohistochemical System, Dako HercepTest, and Vysis PathVysion HER2 FISH using both commercially validated and modified ASCO/CAP and United Kingdom HER2 IHC scoring guidelines.

Science.gov (United States)

O'Grady, Anthony; Allen, David; Happerfield, Lisa; Johnson, Nicola; Provenzano, Elena; Pinder, Sarah E; Tee, Lilian; Gu, Mai; Kay, Elaine W

2010-12-01

Immunohistochemistry (IHC) is used as the frontline assay to determine HER2 status in invasive breast cancer patients. The aim of the study was to compare the performance of the Leica Oracle HER2 Bond IHC System (Oracle) with the current most readily accepted Dako HercepTest (HercepTest), using both commercially validated and modified ASCO/CAP and UK HER2 IHC scoring guidelines. A total of 445 breast cancer samples from 3 international clinical HER2 referral centers were stained with the 2 test systems and scored in a blinded fashion by experienced pathologists. The overall agreement between the 2 tests in a 3×3 (negative, equivocal and positive) analysis shows a concordance of 86.7% and 86.3%, respectively when analyzed using commercially validated and modified ASCO/CAP and UK HER2 IHC scoring guidelines. There is a good concordance between the Oracle and the HercepTest. The advantages of a complete fully automated test such as the Oracle include standardization of key analytical factors and improved turn around time. The implementation of the modified ASCO/CAP and UK HER2 IHC scoring guidelines has minimal effect on either assay interpretation, showing that Oracle can be used as a methodology for accurately determining HER2 IHC status in formalin fixed, paraffin-embedded breast cancer tissue.

Use of enzyme-linked immunosorbent assay and dipstick assay for detection of Strongyloides stercoralis infection in humans

NARCIS (Netherlands)

van Doorn, H. Rogier; Koelewijn, Rob; Hofwegen, Henk; Gilis, Henk; Wetsteyn, Jose C. F. M.; Wismans, Pieter J.; Sarfati, Claudine; Vervoort, Tony; van Gool, Tom

2007-01-01

A homemade enzyme-linked immunosorbent assay (ELISA) (Academic Medical Center ELISA [AMC-ELISA]) and a dipstick assay for the detection of anti-Strongyloides stercoralis antibodies in serum were developed and evaluated together with two commercially available ELISAs (IVD-ELISA [IVD Research, Inc.

Assessment of a robust model protocol with accelerated throughput for a human recombinant full length estrogen receptor-alpha binding assay: protocol optimization and intralaboratory assay performance as initial steps towards validation.

Science.gov (United States)

Freyberger, Alexius; Wilson, Vickie; Weimer, Marc; Tan, Shirlee; Tran, Hoai-Son; Ahr, Hans-Jürgen

2010-08-01

Despite about two decades of research in the field of endocrine active compounds, still no validated human recombinant (hr) estrogen receptor-alpha (ERalpha) binding assay is available, although hr-ERalpha is available from several sources. In a joint effort, US EPA and Bayer Schering Pharma with funding from the EU-sponsored 6th framework project, ReProTect, developed a model protocol for such a binding assay. Important features of this assay are the use of a full length hr-ERalpha and performance in a 96-well plate format. A full length hr-ERalpha was chosen, as it was considered to provide the most accurate and human-relevant results, whereas truncated receptors could perform differently. Besides three reference compounds [17beta-estradiol, norethynodrel, dibutylphthalate] nine test compounds with different affinities for the ERalpha [diethylstilbestrol (DES), ethynylestradiol, meso-hexestrol, equol, genistein, o,p'-DDT, nonylphenol, n-butylparaben, and corticosterone] were used to explore the performance of the assay. Three independent experiments per compound were performed on different days, and dilutions of test compounds from deep-frozen stocks, solutions of radiolabeled ligand and receptor preparation were freshly prepared for each experiment. The ERalpha binding properties of reference and test compounds were well detected. As expected dibutylphthalate and corticosterone were non-binders in this assay. In terms of the relative ranking of binding affinities, there was good agreement with published data obtained from experiments using a human recombinant ERalpha ligand binding domain. Irrespective of the chemical nature of the compound, individual IC(50)-values for a given compound varied by not more than a factor of 2.5. Our data demonstrate that the assay was robust and reliably ranked compounds with strong, weak, and no affinity for the ERalpha with high accuracy. It avoids the manipulation and use of animals, i.e., the preparation of uterine cytosol as

Performance of 2 commercial real-time polymerase chain reaction assays for the detection of Aspergillus and Pneumocystis DNA in bronchoalveolar lavage fluid samples from critical care patients.

Science.gov (United States)

Orsi, Carlotta Francesca; Gennari, William; Venturelli, Claudia; La Regina, Annunziata; Pecorari, Monica; Righi, Elena; Machetti, Marco; Blasi, Elisabetta

2012-06-01

This article investigates the performance of 2 commercial real-time polymerase chain reaction (PCR) assays, MycAssay™ Aspergillus (Myc(Asp)Assay) and MycAssay™ Pneumocystis (Myc(PCP)Assay), on the ABI 7300 platform for the detection of Aspergillus (Asp) or Pneumocystis jirovecii (Pj) DNA in bronchoalveolar lavage (BAL) samples from 20 patients. Operationally, patients enrolled were clustered into 3 groups: invasive aspergillosis group (IA, 7 patients), Pj pneumonia group (PCP, 8 patients), and negative control group (5 patients). All the IA patients were Myc(Asp)Assay positive, whereas 12 non-IA patients returned negative PCR results. Furthermore, 7 of 8 PCP patients were Myc(PCP)Assay positive, while 9 non-PCP patients were PCR negative. In conclusion, these data provide an early indication of the effectiveness of both the Myc(Asp)Assay and Myc(PCP)Assay on the ABI 7300 platform for the detection of either Asp or Pj DNA in BAL from patients with deep fungal infections. Copyright © 2012 Elsevier Inc. All rights reserved.

TCV software test and validation tools and technique. [Terminal Configured Vehicle program for commercial transport aircraft operation

Science.gov (United States)

Straeter, T. A.; Williams, J. R.

1976-01-01

The paper describes techniques for testing and validating software for the TCV (Terminal Configured Vehicle) program which is intended to solve problems associated with operating a commercial transport aircraft in the terminal area. The TCV research test bed is a Boeing 737 specially configured with digital computer systems to carry out automatic navigation, guidance, flight controls, and electronic displays research. The techniques developed for time and cost reduction include automatic documentation aids, an automatic software configuration, and an all software generation and validation system.

Evaluation of five commercially available assays and measurement of serum total protein concentration via refractometry for the diagnosis of failure of passive transfer of immunity in foals.

Science.gov (United States)

Davis, Rachel; Giguère, Steeve

2005-11-15

To determine and compare sensitivity, specificity, accuracy, and predictive values of measurement of serum total protein concentration by refractometry as well as 5 commercially available kits for the diagnosis of failure of passive transfer (FPT) of immunity in foals. Prospective study. 65 foals with various medical problems and 35 clinically normal foals. IgG concentration in serum was assessed by use of zinc sulfate turbidity (assay C), glutaraldehyde coagulation (assay D), 2 semiquantitative immunoassays (assays F and G), and a quantitative immunoassay (assay H). Serum total protein concentration was assessed by refractometry. Radial immunodiffusion (assays A and B) was used as the reference method. For detection of IgG or = 6.0 g/dL indicated adequate IgG concentrations. Most assays were adequate as initial screening tests. However, their use as a definitive test would result in unnecessary treatment of foals with adequate IgG concentrations.

Real-time polymerase chain reaction detection of parvovirus B19 DNA in blood donations using a commercial and an in-house assay.

Science.gov (United States)

Koppelman, M H G M; van Swieten, P; Cuijpers, H T M

2011-06-01

European regulations require testing of manufacturing plasma for parvovirus B19 (B19) DNA to limit the load of this virus to a maximum acceptable level of 10 IU/µL. To meet this requirement, most manufacturers introduced a test algorithm to identify and eliminate high-load donations before making large manufacturing pools of plasma units. Sanquin screens all donations using a commercial assay from Roche and an in-house assay. Between 2006 and 2009, 6.2 million donations were screened using two different polymerase chain reaction (PCR) assays targeting B19 DNA. Donations with B19 DNA loads of greater than 1 × 10(6) IU/mL showing significant differences in viral load between the two assays were further analyzed by sequencing analysis. A total of 396 donations with B19 DNA loads of greater than 1 × 10(6) IU/mL were identified. Fifteen samples (3.8%) had discordant test results; 10 samples (2.5%) were underquantified by the Roche assay, two samples (0.5%) were underquantified by the in-house assay, and three samples (0.8%) were not detected by the Roche assay. Sequencing analysis revealed mismatches in primer and probe-binding regions. Phylogenetic analysis showed that 12 samples were B19 Genotype 1. The three samples not detected by the Roche assay were B19 Genotype 2. This study shows that 3.8% of the viremic B19 DNA-positive donations are not quantified correctly by the Roche or in-house B19 DNA assays. B19 Genotype 1 isolates showing incorrect test results are more common than B19 Genotype 2 or 3 isolates. Newly designed B19 PCR assays for blood screening should preferably have multiplexed formats targeting multiple regions of the B19 genome. © 2010 American Association of Blood Banks.

Performance characteristics of the ARCHITECT anti-HCV assay.

Science.gov (United States)

Jonas, Gesa; Pelzer, Claudia; Beckert, Christian; Hausmann, Michael; Kapprell, Hans-Peter

2005-10-01

The ARCHITECT Anti-HCV assay is a fully automated high throughput chemiluminescent microparticle immunoassay (CMIA) for the detection of antibodies to structural and nonstructural proteins of the hepatitis C virus (HCV). To further enhance the performance of this test, the assay was modified to improve the specificity for blood donor specimens. The specificity of the enhanced ARCHITECT Anti-HCV assay was evaluated by screening blood donor samples randomly collected from various German blood banks, as well as hospitalized patient samples derived from Germany and the US. Additionally, antibody sensitivity was determined on commercially available anti-HCV seroconversion panels and on a commercially available worldwide anti-HCV genotype performance panel. Apparent specificity of the modified ARCHITECT Anti-HCV assay in a blood donor population consisting of 3811 specimens was 99.92%, compared to 99.76% for the current on-market assay. Additionally, antibody sensitivity was determined on commercially available anti-HCV seroconversion panels. Seroconversion sensitivity equivalent to or better than the current on-market product was observed by testing 33 seroconversion panels. This study demonstrates that the modified version of the ARCHITECT Anti-HCV assay shows improved specificity for blood donor specimens compared to the current assay on market without compromising sensitivity. With the availability of the improved ARCHITECT Anti-HCV assay and the recent launch of the ARCHITECT HIV Ag/Ab Combo assay, the ARCHITECT system now offers a full hepatitis/retrovirus menu with excellent performance on a high throughput, random access, automated analyzer, ideally suited for blood screening and diagnostic applications.

Validation of a Pan-Orthopox Real-Time PCR Assay for the Detection and Quantification of Viral Genomes from Nonhuman Primate Blood

Science.gov (United States)

2017-06-19

Validation of a pan-orthopox real-time PCR assay for the detection and quantification of viral genomes from nonhuman primate blood. Eric...medical countermeasures by the U.S. FDA, the assay was designed to quantitate poxvirus genomic DNA in a nonhuman primate (cynomolgus macaque) blood...monkeypox virus into nonhuman primate blood, we chose to use the HA standard after considering the potential biological safety and logistical issues with

The Effect of Different Methods of Fermentation on the Detection of Milk Protein Residues in Retail Cheese by Enzyme-Linked Immunosorbent Assay (ELISA).

Science.gov (United States)

Ivens, Katherine O; Baumert, Joseph L; Hutkins, Robert L; Taylor, Steve L

2017-11-01

Milk and milk products are among the most important allergenic food ingredients, both in the United States and throughout the world; cheeses are among the most important of these milk products. Milk contains several major antigenic proteins, each with differing susceptibilities to proteolytic enzymes. The extent of proteolysis in cheese varies as a result of conditions during manufacture and ripening. Proteolysis has the potential to degrade antigenic and allergenic epitopes that are important for residue detection and elicitation of allergic reactions. Commercial enzyme-linked immunosorbent assays (ELISAs) are not currently validated for use in detecting residues in hydrolyzed or fermented food products. Eighteen retail cheeses produced using 5 different styles of fermentation were investigated for detectable milk protein residues with 4 commercial ELISA kits. Mozzarella, Swiss, Blue, Limburger, and Brie cheeses were assessed. The Neogen Veratox® Casein and Neogen Veratox® Total Milk kits were capable of detecting milk residues in most cheeses evaluated, including blue-veined cheeses that exhibit extensive proteolysis. The other 2 ELISA kits evaluated, r-Biopharm® Fast Casein and ELISA Systems™ Casein, can detect milk residues in cheeses other than blue-veined varieties. ELISA results cannot be quantitatively compared among kits. The quantitative reliability of ELISA results in detection of cheese residues is questionable, but some methods are sufficiently robust to use as a semi-quantitative indication of proper allergen control for the validation of cleaning programs in industry settings. Many commercially available enzyme-linked immunosorbent assays (ELISAs) are not validated for detection of allergenic residues in fermented or hydrolyzed products. This research seeks to determine if commercial milk ELISAs can detect milk residues in varieties of cheese that have undergone different styles of fermentation and different degrees of proteolysis. Only certain

Evaluation of p-phenylenediamine, o-phenylphenol sodium salt, and 2,4-diaminotoluene in the rat comet assay as part of the Japanese Center for the Validation of Alternative Methods (JaCVAM)-initiated international validation study of in vivo rat alkaline comet assay.

Science.gov (United States)

De Boeck, Marlies; van der Leede, Bas-jan; De Vlieger, Kathleen; Geys, Helena; Vynckier, An; Van Gompel, Jacky

2015-07-01

As part of the Japanese Center for the Validation of Alternative Methods (JaCVAM)-initiated international validation study of in vivo rat alkaline comet assay (comet assay), p-phenylenediamine dihydrochloride (PPD), o-phenylphenol sodium salt (OPP), and 2,4-diaminotoluene (2,4-DAT), were analyzed in this laboratory as coded test chemicals. Male Sprague-Dawley rats (7-9 weeks of age) were given three oral doses of the test compounds, 24 and 21 h apart and liver and stomach were sampled 3h after the final dose administration. Under the conditions of the test, no increases in DNA damage were observed in liver and stomach with PPD and OPP up to 100 and 1000 mg/kg/day, respectively. 2,4-DAT, a known genotoxic carcinogen, induced a weak but reproducible, dose-related and statistically significant increase in DNA damage in liver cells while no increases were observed in stomach cells. Copyright © 2015 Elsevier B.V. All rights reserved.

Validation and modification of dried blood spot-based glycosylated hemoglobin assay for the longitudinal aging study in India.

Science.gov (United States)

Hu, Peifeng; Edenfield, Michael; Potter, Alan; Kale, Varsha; Risbud, Arun; Williams, Sharon; Lee, Jinkook; Bloom, David E; Crimmins, Eileen; Seeman, Teresa

2015-01-01

This study aims to validate a modified dried blood spot (DBS)-based glycosylated hemoglobin (HbA1c) assay protocol, after a pretest in India showed poor correlation between the original DBS-based protocol and venous results. The original protocol was tested on different chemistry analyzers and then simplified at the University of Washington (UW). A second pretest was conducted in India to validate the modified assay protocol, using 44 quality control specimens. Data from UW indicated that, using the original protocol, the correlation coefficients between DBS and venous results were above 0.98 on both Bio-Rad and Olympus chemistry analyzers. The protocol worked equally well on filter paper, with or without pre-treatment, and when the recommended amount of blood spot material, or less, was used. A second pretest of the modified protocol confirmed that DBS-based levels from both Olympus and Roche chemistry analyzers were well correlated with DBS results from UW (correlation coefficients were above 0.96), as well as with venous values (correlation coefficients were above 0.94). The DBS-based HbA1c values are highly correlated with venous results. The pre-treatment of filter paper does not appear to be necessary. The poor results from the first pretest are probably due to factors unrelated to the protocol, such as problems with the chemistry analyzer or assay reagents. © 2015 Wiley Periodicals, Inc.

11th GCC Closed Forum: cumulative stability; matrix stability; immunogenicity assays; laboratory manuals; biosimilars; chiral methods; hybrid LBA/LCMS assays; fit-for-purpose validation; China Food and Drug Administration bioanalytical method validation.

Science.gov (United States)

Islam, Rafiq; Briscoe, Chad; Bower, Joseph; Cape, Stephanie; Arnold, Mark; Hayes, Roger; Warren, Mark; Karnik, Shane; Stouffer, Bruce; Xiao, Yi Qun; van der Strate, Barry; Sikkema, Daniel; Fang, Xinping; Tudoroniu, Ariana; Tayyem, Rabab; Brant, Ashley; Spriggs, Franklin; Barry, Colin; Khan, Masood; Keyhani, Anahita; Zimmer, Jennifer; Caturla, Maria Cruz; Couerbe, Philippe; Khadang, Ardeshir; Bourdage, James; Datin, Jim; Zemo, Jennifer; Hughes, Nicola; Fatmi, Saadya; Sheldon, Curtis; Fountain, Scott; Satterwhite, Christina; Colletti, Kelly; Vija, Jenifer; Yu, Mathilde; Stamatopoulos, John; Lin, Jenny; Wilfahrt, Jim; Dinan, Andrew; Ohorodnik, Susan; Hulse, James; Patel, Vimal; Garofolo, Wei; Savoie, Natasha; Brown, Michael; Papac, Damon; Buonarati, Mike; Hristopoulos, George; Beaver, Chris; Boudreau, Nadine; Williard, Clark; Liu, Yansheng; Ray, Gene; Warrino, Dominic; Xu, Allan; Green, Rachel; Hayward-Sewell, Joanne; Marcelletti, John; Sanchez, Christina; Kennedy, Michael; Charles, Jessica St; Bouhajib, Mohammed; Nehls, Corey; Tabler, Edward; Tu, Jing; Joyce, Philip; Iordachescu, Adriana; DuBey, Ira; Lindsay, John; Yamashita, Jim; Wells, Edward

2018-04-01

The 11th Global CRO Council Closed Forum was held in Universal City, CA, USA on 3 April 2017. Representatives from international CRO members offering bioanalytical services were in attendance in order to discuss scientific and regulatory issues specific to bioanalysis. The second CRO-Pharma Scientific Interchange Meeting was held on 7 April 2017, which included Pharma representatives' sharing perspectives on the topics discussed earlier in the week with the CRO members. The issues discussed at the meetings included cumulative stability evaluations, matrix stability evaluations, the 2016 US FDA Immunogenicity Guidance and recent and unexpected FDA Form 483s on immunogenicity assays, the bioanalytical laboratory's role in writing PK sample collection instructions, biosimilars, CRO perspectives on the use of chiral versus achiral methods, hybrid LBA/LCMS assays, applications of fit-for-purpose validation and, at the Global CRO Council Closed Forum only, the status and trend of current regulated bioanalytical practice in China under CFDA's new BMV policy. Conclusions from discussions of these topics at both meetings are included in this report.

Evaluation and optimization of a commercial blocking ELISA for detecting antibodies to influenza A virus for research and surveillance of mallards.

Science.gov (United States)

Shriner, Susan A; VanDalen, Kaci K; Root, J Jeffrey; Sullivan, Heather J

2016-02-01

The availability of a validated commercial assay is an asset for any wildlife investigation. However, commercial products are often developed for use in livestock and are not optimized for wildlife. Consequently, it is incumbent upon researchers and managers to apply commercial products appropriately to optimize program outcomes. We tested more than 800 serum samples from mallards for antibodies to influenza A virus with the IDEXX AI MultiS-Screen Ab test to evaluate assay performance. Applying the test per manufacturer's recommendations resulted in good performance with 84% sensitivity and 100% specificity. However, performance was improved to 98% sensitivity and 98% specificity by increasing the recommended cut-off. Using this alternative threshold for identifying positive and negative samples would greatly improve sample classification, especially for field samples collected months after infection when antibody titers have waned from the initial primary immune response. Furthermore, a threshold that balances sensitivity and specificity reduces estimation bias in seroprevalence estimates. Published by Elsevier B.V.

Comparison of RT-PCR-Dot blot hybridization based on radioisotope 32P with conventional RT-PCR and commercial ELISA Assays for blood screening of HIV-1

International Nuclear Information System (INIS)

Maria Lina R; Andi Yasmon

2011-01-01

There are many commercial ELISA and rapid test kits that have been used for blood screening; however, the kits can give false positive and negative results. Therefore, RT-PCR (Reverse Transcription Polymerase Chain Reaction) - Dot Blot Hybridization based on radioisotope 32 P (RDBR) method was developed in this research, to compare the method with the conventional RT-PCR and commercial ELISA Enzyme-Linked lmmunosorbent Assay) kit. This method is efficient for screening of large blood specimens and surveillance study. Eighty seven samples were used and serum of the samples were tested by ELISA to detect HIV-1. The HIV-l RNA genome was extracted from plasma samples and tested using the RT-PCR and RDBR methods. Of 87 samples that were tested, the rates of positive testing of the RT-PCR, the RDBR, and the ELISA were 71.26%, 74.71%, and 80.46%, respectively. The RDBR (a combination of RTPCR and dot blot hybridization) was more sensitive than conventional RT-PCR by showing 3.45% in increase number of positive specimens. The results showed that of 9 samples (10.34%) were negative RDBR and positive ELISA, while 4 samples (4.60%) were negative ELISA and positive RDBR. The two methods showed slightly difference in the results but further validation is still needed. However, RDBR has high potential as an alternative method for screening of blood in large quantities when compared to method of conventional RT-PCR and ELISA. (author)

Development and Validation of a Rapid Turbidimetric Assay to Determine the Potency of Cefuroxime Sodium in Powder for Dissolution for Injection

Directory of Open Access Journals (Sweden)

Daniela C. M. Vieira

2014-07-01

Full Text Available The cefuroxime sodium is a second generation cephalosporin indicated for infections caused by Gram-positive and Gram-negative microorganisms. Although this drug is highly studied and researched regarding the antimicrobial activity, pharmacokinetics and pharmacodynamics, there are few studies regarding the development of analytical methodology for this cephalosporin. Thus, research involving analytical methods is essential and highly relevant to optimize its analysis in the pharmaceutical industry and guarantee the quality of the product already sold. This study describes the development and validation of a microbiological assay applying the turbidimetric method for the determination of cefuroxime, using Micrococcus luteus ATCC 9341 as micro-organism test and 3x3 parallel line assay design, with nine tubes for each assay, as recommended by the Brazilian Pharmacopoeia. The developed and validated method showed excellent results of linearity, seletivity, precision and robustness, in the concentration range from 30.0 to 120.0 mg/mL, with 100.21% accuracy and content 99.97% to cefuroxime sodium in injectable pharmaceutical form.

Validation of clinical testing for warfarin sensitivity: comparison of CYP2C9-VKORC1 genotyping assays and warfarin-dosing algorithms.

Science.gov (United States)

Langley, Michael R; Booker, Jessica K; Evans, James P; McLeod, Howard L; Weck, Karen E

2009-05-01

Responses to warfarin (Coumadin) anticoagulation therapy are affected by genetic variability in both the CYP2C9 and VKORC1 genes. Validation of pharmacogenetic testing for warfarin responses includes demonstration of analytical validity of testing platforms and of the clinical validity of testing. We compared four platforms for determining the relevant single nucleotide polymorphisms (SNPs) in both CYP2C9 and VKORC1 that are associated with warfarin sensitivity (Third Wave Invader Plus, ParagonDx/Cepheid Smart Cycler, Idaho Technology LightCycler, and AutoGenomics Infiniti). Each method was examined for accuracy, cost, and turnaround time. All genotyping methods demonstrated greater than 95% accuracy for identifying the relevant SNPs (CYP2C9 *2 and *3; VKORC1 -1639 or 1173). The ParagonDx and Idaho Technology assays had the shortest turnaround and hands-on times. The Third Wave assay was readily scalable to higher test volumes but had the longest hands-on time. The AutoGenomics assay interrogated the largest number of SNPs but had the longest turnaround time. Four published warfarin-dosing algorithms (Washington University, UCSF, Louisville, and Newcastle) were compared for accuracy for predicting warfarin dose in a retrospective analysis of a local patient population on long-term, stable warfarin therapy. The predicted doses from both the Washington University and UCSF algorithms demonstrated the best correlation with actual warfarin doses.

Analytical validation of Gentian NGAL particle-enhanced enhanced turbidimetric immunoassay (PETIA

Directory of Open Access Journals (Sweden)

Gian Luca Salvagno

2017-08-01

Full Text Available Objectives: This study was designed to validate the analytical performance of the new Gentian particle-enhanced enhanced turbidimetric immunoassay (PETIA for measuring neutrophil gelatinase-associated lipocalin (NGAL in serum samples. Design and methods: Analytical validation of the Gentian NGAL assay was carried out on a Roche Cobas c501 and was based on assessment of limit of blank (LOB, limit of detection (LOD, functional sensitivity, imprecision, linearity and concordance with the BioPorto NGAL test. Results: The LOB and LOD of Gentian NGAL were found to be 3.8 ng/mL and 6.3 ng/mL, respectively. An analytical coefficient of variation (CV of 20% corresponded to a NGAL value of 10 ng/mL. The intra-assay and inter-assay imprecision (CV was between 0.4 and 5.2% and 0.6 and 7.1% and the total imprecision (CV was 3.7%. The linearity was optimal at NGAL concentrations between 37 and 1420 ng/mL (r=1.00; p<0.001. An excellent correlation was observed between values measured with Gentian NGAL and BioPorto NGAL in 74 routine serum samples (r=0.993. The mean percentage bias of the Gentian assay versus the Bioporto assay was +3.1% (95% CI, +1.6% to +4.5%. Conclusions: These results show that Gentian NGAL may be a viable option to other commercial immunoassays for both routine and urgent assessment of serum NGAL. Keywords: Neutrophil gelatinase-associated lipocalin, NGAL, Analytical validation, Acute kidney injury

Detection of LGI1 and CASPR2 antibodies with a commercial cell-based assay in patients with very high VGKC-complex antibody levels.

Science.gov (United States)

Yeo, T; Chen, Z; Chai, J Y H; Tan, K

2017-07-15

The presence of VGKC-complex antibodies, without LGI1/CASPR2 antibodies, as a standalone marker for neurological autoimmunity remains controversial. Additionally, the lack of an unequivocal VGKC-complex antibody cut-off level defining neurological autoimmunity makes it important to test for monospecific antibodies. We aim to determine the performance characteristics of a commercial assay (Euroimmun, Lübeck, Germany) for LGI1/CASPR2 antibody detection in patients with very high VGKC-complex antibody levels and report their clinico-serological associations. We identified 8 patients in our cohort with the highest VGKC-complex antibody levels (median 2663.5pM, range 933-6730pM) with VGKC-complex antibody related syndromes (Group A). Two other groups were identified; 1 group with suspected neuronal surface antibody syndromes and negative for VGKC-complex antibodies (Group B, n=8), and another group with cerebellar ataxia and negative for onconeuronal antibodies (Group C, n=8). Seven out of 8 patients (87.5%) in Group A had LGI1 and/or CASPR2 antibodies. One Group B patient had LGI1 antibodies but was negative on re-testing with a live cell assay. No Group C patients had monospecific antibodies. Inter-rater reliability was high; combining Groups A and B patients, the kappa statistic was 0.87 and 1.0 for LGI1 and CASPR2 antibodies respectively. We demonstrated that a high proportion of patients with very high VGKC-complex antibody levels and relevant clinical syndromes have LGI1 and/or CASPR2 antibodies detected by the commercial assay. Our findings lend support to the use of the assay for rapid and reliable detection of LGI1 and CASPR2 antibodies. Copyright © 2017 Elsevier B.V. All rights reserved.

Validation and Application of a Dried Blood Spot Assay for Biofilm-Active Antibiotics Commonly Used for Treatment of Prosthetic Implant Infections

Science.gov (United States)

Knippenberg, Ben; Page-Sharp, Madhu; Clark, Ben; Dyer, John; Batty, Kevin T.; Davis, Timothy M. E.

2016-01-01

Dried blood spot (DBS) antibiotic assays can facilitate pharmacokinetic (PK)/pharmacodynamic (PD) studies in situations where venous blood sampling is logistically difficult. We sought to develop, validate, and apply a DBS assay for rifampin (RIF), fusidic acid (FUS), and ciprofloxacin (CIP). These antibiotics are considered active against organisms in biofilms and are therefore commonly used for the treatment of infections associated with prosthetic implants. A liquid chromatography-mass spectroscopy DBS assay was developed and validated, including red cell partitioning and thermal stability for each drug and the rifampin metabolite desacetyl rifampin (Des-RIF). Plasma and DBS concentrations in 10 healthy adults were compared, and the concentration-time profiles were incorporated into population PK models. The limits of quantification for RIF, Des-RIF, CIP, and FUS in DBS were 15 μg/liter, 14 μg/liter, 25 μg/liter, and 153 μg/liter, respectively. Adjusting for hematocrit, red cell partitioning, and relative recovery, DBS-predicted plasma concentrations were comparable to measured plasma concentrations for each antibiotic (r > 0.95; P < 0.0001), and Bland-Altman plots showed no significant bias. The final population PK estimates of clearance, volume of distribution, and time above threshold MICs for measured and DBS-predicted plasma concentrations were comparable. These drugs were stable in DBSs for at least 10 days at room temperature and 1 month at 4°C. The present DBS antibiotic assays are robust and can be used as surrogates for plasma concentrations to provide valid PK and PK/PD data in a variety of clinical situations, including therapeutic drug monitoring or studies of implant infections. PMID:27270283

Development and validation of a quick easily used biochemical assay for evaluating the viability of small immobile arthropods.

Science.gov (United States)

Phillips, Craig B; Iline, Ilia I; Richards, Nicola K; Novoselov, Max; McNeill, Mark R

2013-10-01

Quickly, accurately, and easily assessing the efficacy of treatments to control sessile arthropods (e.g., scale insects) and stationary immature life stages (e.g., eggs and pupae) is problematic because it is difficult to tell whether treated organisms are alive or dead. Current approaches usually involve either maintaining organisms in the laboratory to observe them for development, gauging their response to physical stimulation, or assessing morphological characters such as turgidity and color. These can be slow, technically difficult, or subjective, and the validity of methods other than laboratory rearing has seldom been tested. Here, we describe development and validation of a quick easily used biochemical colorimetric assay for measuring the viability of arthropods that is sufficiently sensitive to test even very small organisms such as white fly eggs. The assay was adapted from a technique for staining the enzyme hexokinase to signal the presence of adenosine triphosphate in viable specimens by reducing a tetrazolium salt to formazan. Basic laboratory facilities and skills are required for production of the stain, but no specialist equipment, expertise, or facilities are needed for its use.

What is required for the validation of in vitro assays for predicting contaminant relative bioavailability? Considerations and criteria

International Nuclear Information System (INIS)

Juhasz, Albert L.; Basta, Nicholas T.; Smith, Euan

2013-01-01

A number of studies have shown the potential of in vitro assays to predict contaminant in vivo relative bioavailability in order to refine human health exposure assessment. Although the term ‘validated’ has been used to describe the goodness of fit between in vivo and in vitro observations, its misuse has arisen from semantic considerations in addition to the lack of defined criteria for establishing performance validation. While several internal validation methods may be utilised, performance validation should preferably focus on assessing the agreement of model predictions with a set of data which are independent of those used to construct the model. In order to achieve robust validated predictive models, a number of parameters (e.g. size of data set, source of independent soils, contaminant concentration range, animal model, relative bioavailability endpoint) need to be considered in addition to defined criteria for establishing performance validation which are currently lacking. -- Defined criteria for establishing in vivo–in vitro performance validation are required in order to ensure robust, defensible predictive models for human health exposure assessment

Performance evaluation of four type-specific commercial assays for detection of herpes simplex virus type 1 antibodies in a Middle East and North Africa population.

Science.gov (United States)

Aldisi, Rana S; Elsidiq, Malaz S; Dargham, Soha R; Sahara, Afifah S; Al-Absi, Enas S; Nofal, Mariam Y; Mohammed, Layla I; Abu-Raddad, Laith J; Nasrallah, Gheyath K

2018-03-22

The number of diagnostic assays for the detection of herpes simplex virus type 1 (HSV-1) antibodies has increased over the years. However, their performance characteristics could vary among global populations. To investigate performance of two commercial ELISA kits, HerpeSelect ® 1 ELISA and Euroimmun Anti-HSV-1 (gC1) ELISA (IgG); and two commercial immunoblot (IB)/Western blot (WB) assays, HerpeSelect ® 1 and 2 Immunoblot IgG, and Euroimmun Anti-HSV-1/HSV-2 gG2 Euroline-WB (IgG/IgM); in detecting HSV-1 antibodies in a Middle East and North Africa (MENA) population. Blood specimens were collected from blood donors in Doha, Qatar, June 2013-2016. Twenty specimens were randomly selected from 10 MENA nationalities (Egypt, Iran, Jordan, Lebanon, Pakistan, Palestine, Qatar, Sudan, Syria, and Yemen; total = 200), and tested for HSV-1 antibodies. Across all six comparisons between assays, positive percent agreement ranged between 95.7% (95% CI: 91.4-98.3%) and 100.0% (95% CI: 97.8-100.0%). Negative percent agreement ranged between 86.2% (95% CI: 68.3-96.1%) and 96.2% (95% CI: 80.4-99.9%). Overall percent agreement ranged between 95.7% (95% CI: 91.7-97.8%) and 99.4% (95% CI: 96.7-99.9%). Cohen's kappa statistic ranged between 0.84 (95% CI: 0.73-0.95) and 0.98 (95% CI: 0.93-1.00). Compared against IB/WB, HerpeSelect ® and Euroimmun had sensitivities and specificities >96% and >86%, respectively. Positive and negative predictive values were >97% and >83%, respectively. The assays showed excellent concordance with one another, and with a high kappa statistic. The ELISA kits demonstrated robust diagnostic performance compared to the IB/WB assays. These findings support the assays' utility in clinical diagnosis and research in MENA populations. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

The Manchester Acute Coronary Syndromes (MACS) decision rule: validation with a new automated assay for heart-type fatty acid binding protein.

Science.gov (United States)

Body, Richard; Burrows, Gillian; Carley, Simon; Lewis, Philip S

2015-10-01

The Manchester Acute Coronary Syndromes (MACS) decision rule may enable acute coronary syndromes to be immediately 'ruled in' or 'ruled out' in the emergency department. The rule incorporates heart-type fatty acid binding protein (h-FABP) and high sensitivity troponin T levels. The rule was previously validated using a semiautomated h-FABP assay that was not practical for clinical implementation. We aimed to validate the rule with an automated h-FABP assay that could be used clinically. In this prospective diagnostic cohort study we included patients presenting to the emergency department with suspected cardiac chest pain. Serum drawn on arrival was tested for h-FABP using an automated immunoturbidimetric assay (Randox) and high sensitivity troponin T (Roche). The primary outcome, a diagnosis of acute myocardial infarction (AMI), was adjudicated based on 12 h troponin testing. A secondary outcome, major adverse cardiac events (MACE; death, AMI, revascularisation or new coronary stenosis), was determined at 30 days. Of the 456 patients included, 78 (17.1%) had AMI and 97 (21.3%) developed MACE. Using the automated h-FABP assay, the MACS rule had the same C-statistic for MACE as the original rule (0.91; 95% CI 0.88 to 0.92). 18.9% of patients were identified as 'very low risk' and thus eligible for immediate discharge with no missed AMIs and a 2.3% incidence of MACE (n=2, both coronary stenoses). 11.1% of patients were classed as 'high-risk' and had a 92.0% incidence of MACE. Our findings validate the performance of a refined MACS rule incorporating an automated h-FABP assay, facilitating use in clinical settings. The effectiveness of this refined rule should be verified in an interventional trial prior to implementation. UK CRN 8376. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

The validation of an invitro colonic motility assay as a biomarker for gastrointestinal adverse drug reactions

International Nuclear Information System (INIS)

Keating, Christopher; Martinez, Vicente; Ewart, Lorna; Gibbons, Stephen; Grundy, Luke; Valentin, Jean-Pierre; Grundy, David

2010-01-01

Motility-related gastrointestinal adverse drug reactions (GADRs), such as constipation and diarrhea, are some of the most frequently reported adverse events associated with the clinical development of new chemical entities, and for marketed drugs. However, biomarkers capable of detecting such GADRs are lacking. Here, we describe an in vitro assay developed to detect and quantify changes in intestinal motility as a surrogate biomarker for constipation/diarrhea-type GADRs. In vitro recordings of intraluminal pressure were used to monitor the presence of colonic peristaltic motor complexes (CPMCs) in mouse colonic segments. CPMC frequency, contractile and total mechanical activity were assessed. To validate the assay, two experimental protocols were conducted. Initially, five drugs with known gastrointestinal effects were tested to determine optimal parameters describing excitation and inhibition as markers for disturbances in colonic motility. This was followed by a 'blinded' evaluation of nine drugs associated with or without clinically identified constipation/diarrhea-type GADRs. Concentration-response relationships were determined for these drugs and the effects were compared with their maximal free therapeutic plasma concentration in humans. The assay detected stimulatory and inhibitory responses, likely correlating to the occurrence of diarrhea or constipation. Concentration-related effects were identified and potential mechanisms of action were inferred for several drugs. Based on the results from the fourteen drugs assessed, the sensitivity of the assay was calculated at 90%, with a specificity of 75% and predictive capacity of 86%. These results support the potential use of this assay in screening for motility-related GADRs during early discovery phase, safety pharmacology assessment.

GMO detection in food and feed through screening by visual loop-mediated isothermal amplification assays.

Science.gov (United States)

Wang, Cong; Li, Rong; Quan, Sheng; Shen, Ping; Zhang, Dabing; Shi, Jianxin; Yang, Litao

2015-06-01

Isothermal DNA/RNA amplification techniques are the primary methodology for developing on-spot rapid nucleic acid amplification assays, and the loop-mediated isothermal amplification (LAMP) technique has been developed and applied in the detection of foodborne pathogens, plant/animal viruses, and genetically modified (GM) food/feed contents. In this study, one set of LAMP assays targeting on eight frequently used universal elements, marker genes, and exogenous target genes, such as CaMV35S promoter, FMV35S promoter, NOS, bar, cry1Ac, CP4 epsps, pat, and NptII, were developed for visual screening of GM contents in plant-derived food samples with high efficiency and accuracy. For these eight LAMP assays, their specificity was evaluated by testing commercial GM plant events and their limits of detection were also determined, which are 10 haploid genome equivalents (HGE) for FMV35S promoter, cry1Ac, and pat assays, as well as five HGE for CaMV35S promoter, bar, NOS terminator, CP4 epsps, and NptII assays. The screening applicability of these LAMP assays was further validated successfully using practical canola, soybean, and maize samples. The results suggested that the established visual LAMP assays are applicable and cost-effective for GM screening in plant-derived food samples.

Validation of commercial business lists as a proxy for licensed alcohol outlets.

Science.gov (United States)

Carlos, Heather A; Gabrielli, Joy; Sargent, James D

2017-05-19

Studies of retail alcohol outlets are restricted to regions due to lack of U.S. national data. Commercial business lists (BL) offer a possible solution, but no data exists to determine if BLs could serve as an adequate proxy for license data. This paper compares geospatial measures of alcohol outlets derived from a commercial BL with license data for a large US state. We validated BL data as a measure of off-premise alcohol outlet density and proximity compared to license data for 5528 randomly selected California residential addresses. We calculated three proximity measures (Euclidean distance, road network travel time and distance) and two density measures (kernel density estimation and the count within a 2-mile radius) for each dataset. The data was acquired in 2015 and processed and analyzed in 2015 and 2016. Correlations and reliabilities between density (correlation 0.98; Cronbach's α 0.97-0.99) and proximity (correlations 0.77-0.86; α 0.87-0.92) measures were high. For proximity, BL data matched license in 55-57% of addresses, overstated distance in 19%, and understated in 24-26%. BL data can serve as a reliable proxy for licensed alcohol outlets, thus extending the work that can be performed in studies on associations between retail alcohol outlets and drinking outcomes.

Validation of the Thermo Scientific SureTect Escherichia coli O157:H7 Real-Time PCR Assay for Raw Beef and Produce Matrixes.

Science.gov (United States)

Cloke, Jonathan; Crowley, Erin; Bird, Patrick; Bastin, Ben; Flannery, Jonathan; Agin, James; Goins, David; Clark, Dorn; Radcliff, Roy; Wickstrand, Nina; Kauppinen, Mikko

2015-01-01

The Thermo Scientific™ SureTect™ Escherichia coli O157:H7 Assay is a new real-time PCR assay which has been validated through the AOAC Research Institute (RI) Performance Tested Methods(SM) program for raw beef and produce matrixes. This validation study specifically validated the assay with 375 g 1:4 and 1:5 ratios of raw ground beef and raw beef trim in comparison to the U.S. Department of Agriculture, Food Safety Inspection Service, Microbiology Laboratory Guidebook (USDS-FSIS/MLG) reference method and 25 g bagged spinach and fresh apple juice at a ratio of 1:10, in comparison to the reference method detailed in the International Organization for Standardization 16654:2001 reference method. For raw beef matrixes, the validation of both 1:4 and 1:5 allows user flexibility with the enrichment protocol, although which of these two ratios chosen by the laboratory should be based on specific test requirements. All matrixes were analyzed by Thermo Fisher Scientific, Microbiology Division, Vantaa, Finland, and Q Laboratories Inc, Cincinnati, Ohio, in the method developer study. Two of the matrixes (raw ground beef at both 1:4 and 1:5 ratios) and bagged spinach were additionally analyzed in the AOAC-RI controlled independent laboratory study, which was conducted by Marshfield Food Safety, Marshfield, Wisconsin. Using probability of detection statistical analysis, no significant difference was demonstrated by the SureTect kit in comparison to the USDA FSIS reference method for raw beef matrixes, or with the ISO reference method for matrixes of bagged spinach and apple juice. Inclusivity and exclusivity testing was conducted with 58 E. coli O157:H7 and 54 non-E. coli O157:H7 isolates, respectively, which demonstrated that the SureTect assay was able to detect all isolates of E. coli O157:H7 analyzed. In addition, all but one of the nontarget isolates were correctly interpreted as negative by the SureTect Software. The single isolate giving a positive result was an E

Validation of secondary commercial data sources for physical activity facilities in urban and nonurban settings.

Science.gov (United States)

Han, Euna; Powell, Lisa; Slater, Sandy; Quinn, Christopher

2012-11-01

Secondary data are often necessary to assess the availability of commercial physical activity (PA) facilities and examine its association with individual behaviors and outcomes, yet the validity of such sources has been explored only in a limited number of studies. Field data were collected on the presence and attributes of commercial PA facilities in a random sample of 30 urban, 15 suburban, and 15 rural Census tracts in the Chicago metropolitan statistical area and surrounding area. Approximately 40% of PA establishments in the field data were listed for both urban and nonurban tracts in both lists except for nonurban tracts in D&B (35%), which was significantly improved in the combined list of D&B and InfoUSA. Approximately one-quarter of the PA facilities listed in D&B were found on the ground, whereas 40% to 50% of PA facilities listed in InfoUSA were found on the ground. PA establishments that offered instruction programs or lessons or that had a court or pool were less likely to be listed, particularly in the nonurban tracts. Secondary commercial business lists on PA facilities should be used with caution in assessing the built environment.

Development and validation of a duplex real-time PCR assay for the diagnosis of equine piroplasmosis.

Science.gov (United States)

Lobanov, Vladislav A; Peckle, Maristela; Massard, Carlos L; Brad Scandrett, W; Gajadhar, Alvin A

2018-03-02

Equine piroplasmosis (EP) is an economically significant infection of horses and other equine species caused by the tick-borne protozoa Theileria equi and Babesia caballi. The long-term carrier state in infected animals makes importation of such subclinical cases a major risk factor for the introduction of EP into non-enzootic areas. Regulatory testing for EP relies on screening of equines by serological methods. The definitive diagnosis of EP infection in individual animals will benefit from the availability of sensitive direct detection methods, for example, when used as confirmatory assays for non-negative serological test results. The objectives of this study were to develop a real-time quantitative polymerase chain reaction (qPCR) assay for simultaneous detection of both agents of EP, perform comprehensive evaluation of its performance and assess the assay's utility for regulatory testing. We developed a duplex qPCR targeting the ema-1 gene of T. equi and the 18S rRNA gene of B. caballi and demonstrated that the assay has high analytical sensitivities for both piroplasm species. Validation of the duplex qPCR on samples from 362 competitive enzyme-linked immunosorbent assay (cELISA)-negative horses from Canada and the United States yielded no false-positive reactions. The assay's performance was further evaluated using samples collected from 430 horses of unknown EP status from a highly endemic area in Brazil. This set of samples was also tested by a single-target 18S rRNA qPCR for T. equi developed at the OIE reference laboratory for EP in Japan, and a previously published single-target 18S rRNA qPCR for B. caballi whose oligonucleotides we adopted for use in the duplex qPCR. Matching serum samples were tested for antibodies to these parasites using cELISA. By the duplex qPCR, T. equi-specific 18S rRNA qPCR and cELISA, infections with T. equi were detected in 87.9% (95% confidence interval, CI: 84.5-90.7%), 90.5% (95% CI: 87.3-92.3%) and 87.4% (95% CI: 84

Biological dosimetry by the triage dicentric chromosome assay - Further validation of international networking

Energy Technology Data Exchange (ETDEWEB)

Wilkins, Ruth C., E-mail: Ruth.Wilkins@hc-sc.gc.ca [Health Canada, Ottawa, ON K1A 0K9 (Canada); Romm, Horst; Oestreicher, Ursula [Bundesamt fur Strahlenschutz, 38226 Salzgitter (Germany); Marro, Leonora [Health Canada, Ottawa, ON K1A 0K9 (Canada); Yoshida, Mitsuaki A. [Biological Dosimetry Section, Dept. of Dose Assessment, Research Center for Radiation Emergency Medicine, NIRS, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Department Radiation Biology, Institute of Radiation Emergency Medicine, Hirosaki University Graduate School of Health Sciences, 66-1 Hon-cho, Hirosaki, Aomori 036-8564 (Japan); Suto, Y. [Biological Dosimetry Section, Dept. of Dose Assessment, Research Center for Radiation Emergency Medicine, NIRS, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Prasanna, Pataje G.S. [National Cancer Institute, Division of Cancer Treatment and Diagnosis, Radiation Research Program, 6130 Executive Blvd., MSC 7440, Bethesda, MD 20892-7440 (United States)

2011-09-15

Biological dosimetry is an essential tool for estimating radiation doses received to personnel when physical dosimetry is not available or inadequate. The current preferred biodosimetry method is based on the measurement of radiation-specific dicentric chromosomes in exposed individuals' peripheral blood lymphocytes. However, this method is labor-, time- and expertise-demanding. Consequently, for mass casualty applications, strategies have been developed to increase its throughput. One such strategy is to develop validated cytogenetic biodosimetry laboratory networks, both national and international. In a previous study, the dicentric chromosome assay (DCA) was validated in our cytogenetic biodosimetry network involving five geographically dispersed laboratories. A complementary strategy to further enhance the throughput of the DCA among inter-laboratory networks is to use a triage DCA where dose assessments are made by truncating the labor-demanding and time-consuming metaphase spread analysis to 20 - 50 metaphase spreads instead of routine 500 - 1000 metaphase spread analysis. Our laboratory network also validated this triage DCA, however, these dose estimates were made using calibration curves generated in each laboratory from the blood samples irradiated in a single laboratory. In an emergency situation, dose estimates made using pre-existing calibration curves which may vary according to radiation type and dose rate and therefore influence the assessed dose. Here, we analyze the effect of using a pre-existing calibration curve on assessed dose among our network laboratories. The dose estimates were made by analyzing 1000 metaphase spreads as well as triage quality scoring and compared to actual physical doses applied to the samples for validation. The dose estimates in the laboratory partners were in good agreement with the applied physical doses and determined to be adequate for guidance in the treatment of acute radiation syndrome.

Evaluation of a molybdenum assay canister

International Nuclear Information System (INIS)

Yoshizumi, T.T.; Keener, S.J.

1988-01-01

The performance characteristics of a commercial molybdenum assay canister were evaluated. The geometrical variation of the technetium-99m (/sup 99m/Tc) activity reading was studied as a function of the elution volume for the standard vials. It was found that the /sup 99m/Tc canister activity reading was ∼ 5% lower than that of the standard method. This is due to attenuation by the canister wall. However, the effect of the geometric variation on the clinical dose preparation was found to be insignificant. The molybdenum-99 ( 99 Mo) contamination level was compared by two methods: (1) the commercial canister and (2) the standard assay kit. The 99 Mo contamination measurements with the canister indicated consistently lower readings than those with the standard 99 Mo assay kit. The authors conclude that the canister may be used in the clinical settings. However, the user must be aware of the problems and the limitations associated with this canister

The Relationship between Different Assays for Detection and Quantification of Amyloid Beta 42 in Human Cerebrospinal Fluid

Directory of Open Access Journals (Sweden)

Teresa A. Ellis

2012-01-01

Full Text Available Alzheimer's disease (AD, which is characterized by a degeneration of neurons and their synapses, is one of the most common forms of dementia. CSF levels of amyloid 42 (A42 have been recognized as a strong candidate to serve as an AD biomarker. There are a number of commercial assays that are routinely employed for measuring A42; however, these assays give diverse ranges for the absolute levels of CSF A42. In order to employ CSF A42 as a biomarker across multiple laboratories, studies need to be performed to understand the relationship between the different platforms. We have analyzed CSF samples from both diseased and nondiseased subjects with two different widely used assay platforms. The results showed that different values for the levels of CSF A42 were reported, depending on the assay used. Nonetheless, both assays clearly demonstrated statistically significant differences in the levels of A42 in CSF from AD relative to age-matched controls (AMC. This paper provides essential data for establishing the relationship between these assays and provides an important step towards the validation of A42 as a biomarker for AD.

Comparison of IgM Capture Enzyme- Linked Immunosorbent Assay (ELISA) using Inhouse method and commercially available MRL kit for serological confirmation of dengue infection

International Nuclear Information System (INIS)

Hapugoda, D.M.; De Silva R, Nilanthi; Abeywickreme, W.; Gunasena, Sunethra; Prithimala, L.D.; Jayawardene, S.L.G.J.; Kumari, Thamara

2003-01-01

Laboratory diagnosis of dengue infection is important for the management of the patients. In this study igM capture ELISA using an inhouse method and commercially available kit (MRL diagnostics,USA) was compared to detect diagnostic capability of Inhouse IgM ELISA for provision of diagnostic facilities to the public at an affordable cost. Eighty acute and convalescent serum samples were collected from serologically confirmed dengue patients. Serological confirmation of patients were performed by Haemagglutination Inhibition (HI) assay, gold standard assay for dengue on paired serum samples. All collected acute and convalescent sera were tested by IgM ELISA using the inhouse method and MRL kit. Antigen and conjugate for the inhouse IgM method were prepared in the laboratory. A cocktail of four dengue antigens containing 25 Antigen ELISA units of each type was prepared and used as the assay antigen. Conjugate was prepared using a serum sample with high dengue Anti flavi IgG antibody titre conjugated with Horseradish peroxidase. A prospective study of both IgM ELISA assays were performed using 113 acute sera collected from dengue suspected cases. Overall results showed that 46% and 52% acute sera collected from dengue confirmed patients were positive by inhouse ELISA assay and MRL kits respectively. In the prospective study done using acute sera collected from dengue suspected patients showed that 44% and 52% were positive by inhouse ELISA assay and MRL kits. There was no significant difference in positivity between these two assays. (P=0.18). Inhouse IgM ELISA can be used for provision of laboratory diagnosis of dengue virus infection more than 5 days. The assay is 10 times less costly than using MRL kits as assay antigen and conjugate can be prepared easily in the laboratory

Validation of an accelerated high-sensitivity troponin T assay protocol in an Australian cohort with chest pain.

Science.gov (United States)

Parsonage, William A; Greenslade, Jaimi H; Hammett, Christopher J; Lamanna, Arvin; Tate, Jillian R; Ungerer, Jacobus P; Chu, Kevin; Than, Martin; Brown, Anthony F T; Cullen, Louise

2014-02-17

To validate an accelerated biomarker strategy using a high-sensitivity cardiac troponin T (hs-cTnT) assay for diagnosing acute myocardial infarction (AMI) in patients presenting to the emergency department with chest pain; and to validate this strategy in combination with the National Heart Foundation of Australia/Cardiac Society of Australia and New Zealand risk stratification model. Single-centre, prospective, observational cohort study of 764 adults presenting to a tertiary hospital with symptoms of possible acute coronary syndrome between November 2008 and February 2011. AMI or cardiac death within 24 hours of presentation (primary), and major adverse cardiac events within 30 days (secondary). An elevated hs-cTnT assay result above the 99th percentile at either the 0 h or 2 h time points had sensitivity of 96.4% (95% CI, 87.9%-99.0%), specificity of 82.6% (95% CI, 79.7%-85.2%), negative predictive value of 99.7% (95% CI, 98.8%-99.9%) and positive predictive value of 30.5% (95% CI, 24.2%-37.6%) for diagnosing AMI. Compared with a traditional 6 h cardiac troponin testing strategy, the accelerated strategy led to reclassification of risk in only two patients with adverse cardiac outcomes, with no net effect on appropriate management. In patients presenting with chest pain, an accelerated biomarker strategy using the hs-cTnT assay performed well in the initial diagnosis of AMI. The accelerated strategy was also effective when incorporated into a comprehensive strategy of risk stratification that included clinical and demographic factors. The time saved by this approach could have a major impact on health service delivery. Australian New Zealand Clinical Trials Registry ACTRN12610000053022.

Validation, optimisation, and application data in support of the development of a targeted selected ion monitoring assay for degraded cardiac troponin T

Directory of Open Access Journals (Sweden)

Alexander S. Streng

2016-06-01

Full Text Available Cardiac troponin T (cTnT fragmentation in human serum was investigated using a newly developed targeted selected ion monitoring assay, as described in the accompanying article: “Development of a targeted selected ion monitoring assay for the elucidation of protease induced structural changes in cardiac troponin T” [1]. This article presents data describing aspects of the validation and optimisation of this assay. The data consists of several figures, an excel file containing the results of a sequence identity search, and a description of the raw mass spectrometry (MS data files, deposited in the ProteomeXchange repository with id PRIDE: http://www.ebi.ac.uk/pride/archive/projects/PXD003187.

Comparison and validation of ELISA assays for plasma insulin-like ...

African Journals Online (AJOL)

1 in the horse. ... accurate and precise of the three kits; the other two assays gave apparently much lower concentrations, with poor recovery of spiked recombinant human IGF-1 and unacceptably poor intra-assay coefficients of variation (CV).

Recommendations for the validation of cell-based assays used for the detection of neutralizing antibody immune responses elicited against biological therapeutics.

Science.gov (United States)

Gupta, Shalini; Devanarayan, Viswanath; Finco, Deborah; Gunn, George R; Kirshner, Susan; Richards, Susan; Rup, Bonita; Song, An; Subramanyam, Meena

2011-07-15

The administration of biological therapeutics may result in the development of anti-drug antibodies (ADAs) in treated subjects. In some cases, ADA responses may result in the loss of therapeutic efficacy due to the formation of neutralizing ADAs (NAbs). An important characteristic of anti-drug NAbs is their direct inhibitory effect on the pharmacological activity of the therapeutic. Neutralizing antibody responses are of particular concern for biologic products with an endogenous homolog whose activity can be potentially dampened or completely inhibited by the NAbs leading to an autoimmune-type deficiency syndrome. Therefore, it is important that ADAs are detected and characterized appropriately using sensitive and reliable methods. The design, development and optimization of cell-based assays used for detection of NAbs have been published previously by Gupta et al. 2007 [1]. This paper provides recommendations on best practices for the validation of cell-based NAb assay and suggested validation parameters based on the experience of the authors. Copyright © 2011 Elsevier B.V. All rights reserved.

An inter-laboratory validation of a real time PCR assay to measure host excretion of bacterial pathogens, particularly of Mycobacterium bovis.

Directory of Open Access Journals (Sweden)

Emma R Travis

Full Text Available Advances in the diagnosis of Mycobacterium bovis infection in wildlife hosts may benefit the development of sustainable approaches to the management of bovine tuberculosis in cattle. In the present study, three laboratories from two different countries participated in a validation trial to evaluate the reliability and reproducibility of a real time PCR assay in the detection and quantification of M. bovis from environmental samples. The sample panels consisted of negative badger faeces spiked with a dilution series of M. bovis BCG Pasteur and of field samples of faeces from badgers of unknown infection status taken from badger latrines in areas with high and low incidence of bovine TB (bTB in cattle. Samples were tested with a previously optimised methodology. The experimental design involved rigorous testing which highlighted a number of potential pitfalls in the analysis of environmental samples using real time PCR. Despite minor variation between operators and laboratories, the validation study demonstrated good concordance between the three laboratories: on the spiked panels, the test showed high levels of agreement in terms of positive/negative detection, with high specificity (100% and high sensitivity (97% at levels of 10(5 cells g(-1 and above. Quantitative analysis of the data revealed low variability in recovery of BCG cells between laboratories and operators. On the field samples, the test showed high reproducibility both in terms of positive/negative detection and in the number of cells detected, despite low numbers of samples identified as positive by any laboratory. Use of a parallel PCR inhibition control assay revealed negligible PCR-interfering chemicals co-extracted with the DNA. This is the first example of a multi-laboratory validation of a real time PCR assay for the detection of mycobacteria in environmental samples. Field studies are now required to determine how best to apply the assay for population-level b

An European inter-laboratory validation of alternative endpoints of the murine local lymph node assay

International Nuclear Information System (INIS)

Ehling, G.; Hecht, M.; Heusener, A.; Huesler, J.; Gamer, A.O.; Loveren, H. van; Maurer, Th.; Riecke, K.; Ullmann, L.; Ulrich, P.; Vandebriel, R.; Vohr, H.-W.

2005-01-01

The original local lymph node assay (LLNA) is based on the use of radioactive labelling to measure cell proliferation. Other endpoints for the assessment of proliferation are also authorized by the OECD Guideline 429 provided there is appropriate scientific support, including full citations and description of the methodology (OECD, 2002. OECD Guideline for the Testing of Chemicals; Skin Sensitization: Local Lymph Node Assay, Guideline 429. Paris, adopted 24th April 2002.). Here, we describe the outcome of the second round of an inter-laboratory validation of alternative endpoints in the LLNA conducted in nine laboratories in Europe. The validation study was managed and supervised by the Swiss Agency for Therapeutic Products (Swissmedic) in Bern. Ear-draining lymph node (LN) weight and cell counts were used to assess LN cell proliferation instead of [3H]TdR incorporation. In addition, the acute inflammatory skin reaction was measured by ear weight determination of circular biopsies of the ears to identify skin irritation properties of the test items. The statistical analysis was performed in the department of statistics at the university of Bern. Similar to the EC 3 values defined for the radioactive method, threshold values were calculated for the endpoints measured in this modification of the LLNA. It was concluded that all parameters measured have to be taken into consideration for the categorisation of compounds due to their sensitising potencies. Therefore, an assessment scheme has been developed which turned out to be of great importance to consistently assess sensitisation versus irritancy based on the data of the different parameters. In contrast to the radioactive method, irritants have been picked up by all the laboratories applying this assessment scheme

Commercial enzyme-linked immunosorbent assay versuspolymerase chain reaction for the diagnosis of chronic Chagas disease: a systematic review and meta-analysis

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Pedro Emmanuel Alvarenga Americano do Brasil

2016-01-01

Full Text Available Chronic Chagas disease diagnosis relies on laboratory tests due to its clinical characteristics. The aim of this research was to review commercial enzyme-linked immunosorbent assay (ELISA and polymerase chain reaction (PCR diagnostic test performance. Performance of commercial ELISA or PCR for the diagnosis of chronic Chagas disease were systematically searched in PubMed, Scopus, Embase, ISI Web, and LILACS through the bibliography from 1980-2014 and by contact with the manufacturers. The risk of bias was assessed with QUADAS-2. Heterogeneity was estimated with the I2 statistic. Accuracies provided by the manufacturers usually overestimate the accuracy provided by academia. The risk of bias is high in most tests and in most QUADAS dimensions. Heterogeneity is high in either sensitivity, specificity, or both. The evidence regarding commercial ELISA and ELISA-rec sensitivity and specificity indicates that there is overestimation. The current recommendation to use two simultaneous serological tests can be supported by the risk of bias analysis and the amount of heterogeneity but not by the observed accuracies. The usefulness of PCR tests are debatable and health care providers should not order them on a routine basis. PCR may be used in selected cases due to its potential to detect seronegative subjects.

Characterization and Validation of the LT-SYS Copper Assay on a Roche Cobas 8000 c502 Analyzer.

Science.gov (United States)

Kraus, F Bernhard; Mischereit, Marlies; Eller, Christoph; Ludwig-Kraus, Beatrice

2017-02-01

Validation of the LT-SYS quantitative in vitro copper assay on a Roche Cobas 8000 c502 analyzer and comparison with a BIOMED assay on a Roche Cobas Mira analyzer. Imprecision and bias were quantified at different concentration levels (serum and plasma) over a 20-day period. Linearity was assessed covering a range from 4.08 µmol/L to 33.8 µmol/L. Limit of blank (LoB) and limit of detection (LoD) were established based on a total of 120 blank and low-level samples. The method comparison was based on 58 plasma samples. Within-run imprecision ranged from 0.7% to 1.2% and within-laboratory imprecision from 1.4% to 3.3%. Relative bias for the 2 serum pools with known target values was less than 2.5%. The assay did not deviate from linearity over the tested measuring range. LoB and LoD were 0.12 µmol/L and 0.23 µmol/L, respectively. The method comparison revealed an average deviation of 11.5% (2.016 µmol/L), and the linear regression fit was y = 1.464 + 0.795x. The LT-SYS copper assay characterized in this study showed a fully acceptable performance with good degrees of imprecision and bias, no deviation from linearity in the relevant measuring rangem, and very low LoB and LoD. © American Society for Clinical Pathology, 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Validation of an improved enzyme-linked immunosorbent assay for the diagnosis of trypanosomal antibodies in Ghanaian cattle

International Nuclear Information System (INIS)

Doku, C.K.; Seidu, I.B.M.

2000-01-01

The validation of an enzyme-linked immunosorbent assay (Ab-ELISA) for the detection of antibodies to pathogenic trypanosomes in cattle is described. Two hundred known negative sera obtained from the tsetse-free zone of Dori (Burkina Faso) were analyzed using microtitre plates pre-coated with crude antigen lysates of Trypanosoma congolense and T. vivax. A pre-test optimization was carried out and a percent positivity (PP) of 50% was chosen (specificity: >82%) for assaying field sera. A total of 440 serum samples collected from cattle in areas of known and unknown disease prevalence were assayed. For all animals the packed red cell volume (PCV) was determined and the buffy coat technique (BCT) and blood smears were examined to detect trypanosomes at the species level. A comparison of the BCT and Ab-ELISA results showed there was a much higher prevalence of antibodies to both species than the parasite prevalence as shown by the BCT (10 fold). The rate of agreement between BCT-positive and Ab-ELISA-positive samples for both species was low (<10%). No conclusion could be drawn from this finding because of the low number of known BCT positive cases that were identified. There was a better, albeit highly variable, agreement between BCT-negative and Ab-ELISA-negative samples (30-70%). Proposals for further improvement of the Ab-ELISA and prospects for the use of the assay in the monitoring of trypanosomosis control in Ghana are discussed. (author)

Validation of a commercial dry-form broth microdilution device (Sensititre) for testing tedizolid, a new oxazolidinone.

Science.gov (United States)

Jones, Ronald N; Holliday, Nicole M; Rhomberg, Paul R

2015-02-01

Tedizolid, a novel oxazolidinone antibacterial with potent activity against a wide range of Gram-positive pathogens, was recently approved by regulatory authorities for the treatment of acute bacterial skin and skin structure infections. A commercial broth microdilution device (Sensititre; Thermo Fisher Scientific) was validated using 285 selected Gram-positive isolates, and the device was documented to have 100.0% essential and categorical agreement with reference MIC results and excellent MIC endpoint reproducibility. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Development and validation of stability indicating UPLC assay method for ziprasidone active pharma ingredient

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Sonam Mittal

2012-01-01

Full Text Available Background: Ziprasidone, a novel antipsychotic, exhibits a potent highly selective antagonistic activity on D2 and 5HT2A receptors. Literature survey for ziprasidone revealed several analytical methods based on different techniques but no UPLC method has been reported so far. Aim: Aim of this research paper is to present a simple and rapid stability indicating isocratic, ultra performance liquid chromatographic (UPLC method which was developed and validated for the determination of ziprasidone active pharmaceutical ingredient. Forced degradation studies of ziprasidone were studied under acid, base, oxidative hydrolysis, thermal stress and photo stress conditions. Materials and Methods: The quantitative determination of ziprasidone drug was performed on a Supelco analytical column (100×2.1 mm i.d., 2.7 ΅m with 10 mM ammonium acetate buffer (pH: 6.7 and acetonitrile (ACN as mobile phase with the ratio (55:45-Buffer:ACN at a flow rate of 0.35 ml/ min. For UPLC method, UV detection was made at 318 nm and the run time was 3 min. Developed UPLC method was validated as per ICH guidelines. Results and Conclusion: Mild degradation of the drug substance was observed during oxidative hydrolysis and considerable degradation observed during basic hydrolysis. During method validation, parameters such as precision, linearity, ruggedness, stability, robustness, and specificity were evaluated, which remained within acceptable limits. Developed UPLC method was successfully applied for evaluating assay of Ziprasidone active Pharma ingredient.

Validity of a commercial kit for detection of antibodies in bovine serum in an endemic area for fasciolosis

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Aline Nunes Simões

Full Text Available Abstract Fasciolosis is caused by Fasciola hepatica that affects the bile ducts and liver parenchyma of ruminants, which can result in economic loss. This study aimed to carry out the validity of the commercial kit ELISA® indirect front of the simple fecal sedimentation test used as the standard. 143 samples were collected blood and feces of cattle from Jerome, south of the Espírito Santo. Serum samples were left at -80 °C and used to perform the ELISA kit IDEXX®. All animals to stool examinations were also positive to the ELISA (22 and negative samples to test stool (121, 52 animals reacted positively against the antibody research. The frequency of fasciolosis was 15.4% in the stool examinations and 51.8% by ELISA. The validity was calculated by sensitivity (100%, specificity (57%, positive predictive value (29% and negative predictive value (100%, and the correlation between the tests calculated using the kappa index of 0.35. The better sensitivity of the ELISA commercial kit should not be a separately evaluated, since the cost benefit and the technical facility must be considered.

Evaluation of methyl methanesulfonate, 2,6-diaminotoluene and 5-fluorouracil: Part of the Japanese center for the validation of alternative methods (JaCVAM) international validation study of the in vivo rat alkaline comet assay.

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Plappert-Helbig, Ulla; Junker-Walker, Ursula; Martus, Hans-Joerg

2015-07-01

As a part of the Japanese Center for the Validation of Alternative Methods (JaCVAM)-initiative international validation study of the in vivo rat alkaline comet assay (comet assay), we examined methyl methanesulfonate, 2,6-diaminotoluene, and 5-fluorouracil under coded test conditions. Rats were treated orally with the maximum tolerated dose (MTD) and two additional descending doses of the respective compounds. In the MMS treated groups liver and stomach showed significantly elevated DNA damage at each dose level and a significant dose-response relationship. 2,6-diaminotoluene induced significantly elevated DNA damage in the liver at each dose and a statistically significant dose-response relationship whereas no DNA damage was obtained in the stomach. 5-fluorouracil did not induce DNA damage in either liver or stomach. Copyright © 2015 Elsevier B.V. All rights reserved.

Commercially available molecular tests for human papillomaviruses (HPV): 2015 update.

Science.gov (United States)

Poljak, Mario; Kocjan, Boštjan J; Oštrbenk, Anja; Seme, Katja

2016-03-01

Commercial molecular tests for human papillomaviruses (HPV) are invaluable diagnostic tools in cervical carcinoma screening and management of women with cervical precancerous lesions as well as important research tools for epidemiological studies, vaccine development, and implementation and monitoring of vaccination programs. In this third inventory of commercial HPV tests, we identified 193 distinct commercial HPV tests and at least 127 test variants available on the market in 2015, which represents a 54% and 79% increase in the number of distinct HPV tests and variants, respectively, in comparison to our last inventory performed in 2012. Identified HPV tests were provisionally divided into eight main groups and several subgroups. Among the 193 commercial HPV tests, all but two target alpha-HPV types only. Although the number of commercial HPV tests with at least one published study in peer-reviewed literature has increased significantly in the last three years, several published performance evaluations are still not in line with agreed-upon standards in the HPV community. Manufacturers should invest greater effort into evaluating their products and publishing validation/evaluation results in peer-reviewed journals. To achieve this, more clinically oriented external quality-control panels and initiatives are required. For evaluating the analytical performance of the entire range of HPV tests currently on the market, more diverse and reliable external quality-control programs based on international standards for all important HPV types are indispensable. The performance of a wider range of HPV tests must be promptly evaluated on a variety of alternative clinical specimens. In addition, more complete HPV assays containing validated sample-extraction protocols and appropriate internal controls are urgently needed. Provision of a broader range of automated systems allowing large-scale HPV testing as well as the development of reliable, rapid, and affordable molecular

Polymerase chain reaction assay for verifying the labeling of meat and commercial meat products from game birds targeting specific sequences from the mitochondrial D-loop region.

Science.gov (United States)

Rojas, M; González, I; Pavón, M A; Pegels, N; Hernández, P E; García, T; Martín, R

2010-05-01

A PCR assay was developed for the identification of meats and commercial meat products from quail (Coturnix coturnix), pheasant (Phasianus colchicus), partridge (Alectoris spp.), guinea fowl (Numida meleagris), pigeon (Columba spp.), Eurasian woodcock (Scolopax rusticola), and song thrush (Turdus philomelos) based on oligonucleotide primers targeting specific sequences from the mitochondrial D-loop region. The primers designed generated specific fragments of 96, 100, 104, 106, 147, 127, and 154 bp in length for quail, pheasant, partridge, guinea fowl, pigeon, Eurasian woodcock, and song thrush tissues, respectively. The specificity of each primer pair was tested against DNA from various game and domestic species. In this work, satisfactory amplification was accomplished in the analysis of experimentally pasteurized (72 degrees C for 30 min) and sterilized (121 degrees C for 20 min) meats, as well as in commercial meat products from the target species. The technique was also applied to raw and sterilized muscular binary mixtures, with a detection limit of 0.1% (wt/wt) for each of the targeted species. The proposed PCR assay represents a rapid and straightforward method for the detection of possible mislabeling in game bird meat products.

Analytical validation of the PAM50-based Prosigna Breast Cancer Prognostic Gene Signature Assay and nCounter Analysis System using formalin-fixed paraffin-embedded breast tumor specimens

International Nuclear Information System (INIS)

Nielsen, Torsten; Storhoff, James; Wallden, Brett; Schaper, Carl; Ferree, Sean; Liu, Shuzhen; Gao, Dongxia; Barry, Garrett; Dowidar, Naeem; Maysuria, Malini

2014-01-01

NanoString’s Prosigna™ Breast Cancer Prognostic Gene Signature Assay is based on the PAM50 gene expression signature. The test outputs a risk of recurrence (ROR) score, risk category, and intrinsic subtype (Luminal A/B, HER2-enriched, Basal-like). The studies described here were designed to validate the analytical performance of the test on the nCounter Analysis System across multiple laboratories. Analytical precision was measured by testing five breast tumor RNA samples across 3 sites. Reproducibility was measured by testing replicate tissue sections from 43 FFPE breast tumor blocks across 3 sites following independent pathology review at each site. The RNA input range was validated by comparing assay results at the extremes of the specified range to the nominal RNA input level. Interference was evaluated by including non-tumor tissue into the test. The measured standard deviation (SD) was less than 1 ROR unit within the analytical precision study and the measured total SD was 2.9 ROR units within the reproducibility study. The ROR scores for RNA inputs at the extremes of the range were the same as those at the nominal input level. Assay results were stable in the presence of moderate amounts of surrounding non-tumor tissue (<70% by area). The analytical performance of NanoString’s Prosigna assay has been validated using FFPE breast tumor specimens across multiple clinical testing laboratories

Calculations for Adjusting Endogenous Biomarker Levels During Analytical Recovery Assessments for Ligand-Binding Assay Bioanalytical Method Validation.

Science.gov (United States)

Marcelletti, John F; Evans, Cindy L; Saxena, Manju; Lopez, Adriana E

2015-07-01

It is often necessary to adjust for detectable endogenous biomarker levels in spiked validation samples (VS) and in selectivity determinations during bioanalytical method validation for ligand-binding assays (LBA) with a matrix like normal human serum (NHS). Described herein are case studies of biomarker analyses using multiplex LBA which highlight the challenges associated with such adjustments when calculating percent analytical recovery (%AR). The LBA test methods were the Meso Scale Discovery V-PLEX® proinflammatory and cytokine panels with NHS as test matrix. The NHS matrix blank exhibited varied endogenous content of the 20 individual cytokines before spiking, ranging from undetectable to readily quantifiable. Addition and subtraction methods for adjusting endogenous cytokine levels in %AR calculations are both used in the bioanalytical field. The two methods were compared in %AR calculations following spiking and analysis of VS for cytokines having detectable endogenous levels in NHS. Calculations for %AR obtained by subtracting quantifiable endogenous biomarker concentrations from the respective total analytical VS values yielded reproducible and credible conclusions. The addition method, in contrast, yielded %AR conclusions that were frequently unreliable and discordant with values obtained with the subtraction adjustment method. It is shown that subtraction of assay signal attributable to matrix is a feasible alternative when endogenous biomarkers levels are below the limit of quantitation, but above the limit of detection. These analyses confirm that the subtraction method is preferable over that using addition to adjust for detectable endogenous biomarker levels when calculating %AR for biomarker LBA.

Collaborative study for the validation of an improved HPLC assay for recombinant IFN-alfa-2.

Science.gov (United States)

Jönsson, K H; Daas, A; Buchheit, K H; Terao, E

2016-01-01

The current European Pharmacopoeia (Ph. Eur.) texts for Interferon (IFN)-alfa-2 include a nonspecific photometric protein assay using albumin as calibrator and a highly variable cell-based assay for the potency determination of the protective effects. A request was expressed by the Official Medicines Control Laboratories (OMCLs) for improved methods for the batch control of recombinant interferon alfa-2 bulk and market surveillance testing of finished products, including those formulated with Human Serum Albumin (HSA). A HPLC method was developed at the Medical Products Agency (MPA, Sweden) for the testing of IFN-alfa-2 products. An initial collaborative study run under the Biological Standardisation Programme (BSP; study code BSP039) revealed the need for minor changes to improve linearity of the calibration curves, assay reproducibility and robustness. The goal of the collaborative study, coded BSP071, was to transfer and further validate this improved HPLC method. Ten laboratories participated in the study. Four marketed IFN-alfa-2 preparations (one containing HSA) together with the Ph. Eur. Chemical Reference Substance (CRS) for IFN-alfa-2a and IFN-alfa-2b, and in-house reference standards from two manufacturers were used for the quantitative assay. The modified method was successfully transferred to all laboratories despite local variation in equipment. The resolution between the main and the oxidised forms of IFN-alfa-2 was improved compared to the results from the BSP039 study. The improved method even allowed partial resolution of an extra peak after the principal peak. Symmetry of the main IFN peak was acceptable for all samples in all laboratories. Calibration curves established with the Ph. Eur. IFN-alfa-2a and IFN-alfa-2b CRSs showed excellent linearity with intercepts close to the origin and coefficients of determination greater than 0.9995. Assay repeatability, intermediate precision and reproducibility varied with the tested sample within acceptable

Evaluation and validation of a real-time PCR assay for detection and quantitation of human adenovirus 14 from clinical samples.

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David Metzgar

Full Text Available In 2007, the Centers for Disease Control and Prevention (CDC reported that Human adenovirus type 14 (HAdV-14 infected 106 military personnel and was responsible for the death of one U.S. soldier at Lackland Air Force Base in Texas. Identification of the responsible adenovirus, which had not previously been seen in North America and for which rapid diagnostic tools were unavailable, required retrospective analysis at reference laboratories. Initial quarantine measures were also reliant on relatively slow traditional PCR analysis at other locations. To address this problem, we developed a real-time PCR assay that detects a 225 base pair sequence in the HAdV-14a hexon gene. Fifty-one oropharyngeal swab specimens from the Naval Health Research Center, San Diego, CA and Advanced Diagnostic Laboratory, Lackland AFB, TX were used to validate the new assay. The described assay detected eight of eight and 19 of 19 confirmed HAdV-14a clinical isolates in two separate cohorts from respiratory disease outbreaks. The real-time PCR assay had a wide dynamic range, detecting from 10(2 to 10(7 copies of genomic DNA per reaction. The assay did not cross-react with other adenoviruses, influenza, respiratory syncytial virus, or common respiratory tract bacteria. The described assay is easy to use, sensitive and specific for HAdV-14a in clinical throat swab specimens, and very rapid since turnaround time is less than four hours to obtain an answer.

Validation and pharmacological characterisation of MK-801-induced locomotor hyperactivity in BALB/C mice as an assay for detection of novel antipsychotics.

Science.gov (United States)

Bradford, Andrea M; Savage, Kevin M; Jones, Declan N C; Kalinichev, Mikhail

2010-10-01

We evaluated locomotor hyperactivity induced in BALB/C mice by an N-methyl-D-aspartate receptor antagonist MK-801 as an assay for the detection of antipsychotic drugs. We assessed the effects of antipsychotic drugs to validate the assay (study 1), selective dopamine and serotonin ligands for pharmacological characterisation of the model (study 2) and a number of compounds with efficacy in models of schizophrenia to understand the predictive validity of the model (study 3). Adult males (n  = 9/group) were pretreated with a test compound, habituated to locomotor activity cages before receiving MK-801 (0.32 mg/kg) and activity recorded for a further 75 or 120 min. In study 1, we tested haloperidol, clozapine, olanzapine, risperidone, ziprasidone, aripiprazole, sertindole and quetiapine. In study 2, we tested SCH23390 (D(1) antagonist), sulpiride (D(2)/D(3) antagonist), raclopride (D(2)/D(3) antagonist), SB-277011 (D(3) antagonist), L-745,870 (D(4) antagonist), WAY100635 (5-HT(1A) antagonist), 8-OH-DPAT (5-HT(1A) agonist), ketanserin (5-HT(2A)/5-HT(2C) antagonist) and SB-242084 (5-HT(2C) antagonist). In study 3, we tested xanomeline (M(1)/M(4) receptor agonist), LY379268 (mGluR2/3 receptor agonist), diazepam (GABA(A) modulator) and thioperamide (H(3) receptor antagonist). All antipsychotics suppressed MK-801-induced hyperactivity in a dose-dependent and specific manner. The effects of antipsychotics appear to be mediated via dopamine D(1), D(2) and 5-HT(2) receptors. Xanomeline, LY379268 and diazepam were active in this assay while thioperamide was not. MK-801-induced hyperactivity in BALB/C mice model of positive symptoms has shown predictive validity with novel compounds acing at M(1)/M(4), mGluR2/3 and GABA(A) receptors and can be used as a screening assay for detection of novel pharmacotherapies targeting those receptors.

How valid are commercially available medical simulators?

NARCIS (Netherlands)

Stunt, J.J.; Wulms, P.H.; Kerkhoffs, G.M.; Dankelman, J.; Van Dijk, C.N.; Tuijthof, G.J.M.

2014-01-01

Background: Since simulators offer important advantages, they are increasingly used in medical education and medical skills training that require physical actions. A wide variety of simulators have become commercially available. It is of high importance that evidence is provided that training on

Comparative Assessment of Anti-HLA Antibodies Using Two Commercially Available Luminex-Based Assays

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Kevin J. Clerkin, MD, MSc

2017-11-01

Conclusions. Immucor and One Lambda/ThermoFisher assays have a similar, albeit nonidentical, ability to detect anti-HLA Ab. Although the correlation between the assays was present, significant variances exist, some of which can be explained by a dilution-sensitive “prozone” effect.

Design and Validation Testing of TruckScan to Assay Large Sacks of Fukushima Radioactive Debris on a Truck

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Atsuo [Canberra-Japan (Japan); Bronson, Frazier [Canberra Industries Inc. (United States)

2015-07-01

As a result of the March 2011 earthquake and resulting tsunami in Japan, there was a serious accident at the Fukushima Dai-ichi Nuclear Power Plant. This accident has contaminated soil and vegetation in a wide area around the plant. Decontamination projects over the last 4 years have resulted in large numbers of 1 cubic meter canvas bags of debris, commonly called Super Sacks [SS]. These are currently stored nearby where they were generated, but starting in 2015, they will be moved to various Interim Storage Facilities [ISF]. Trucks will typically carry 8-20 of these SSs. When the trucks arrive at the ISF they need to be rapidly sorted into groups according to radioactivity level, for efficient subsequent processing. Canberra Industries, Inc. [CI] has designed a new truck monitoring system 'TruckScan' for use at these ISFs. The TruckScan system must measure the entire truck loaded with multiple closely packed SSs, and generate a nuclide specific assay report showing the radioactivity in each individual SS. The Canberra-Japan office, along with Obayashi Corporation have performed validation testing to demonstrate to the regulatory authorities that the proposed technique was sufficiently accurate. These validation tests were conducted at a temporary storage area in Fukushima prefecture. Decontaminated waste of various representative types and of various levels of radioactivity was gathered and mixed to create homogeneous volumes. These volumes were sampled multiple times and assayed with laboratory HPGe detectors to determine the reference concentration of each pile. Multiple SSs were loaded from each pile. Some of the SSs were filled 50% full, others 75% full, and others 100% full, to represent the typical loading configuration of the existing SSs in the field. The content of the SSs are either sand, soil, or vegetation with densities ranging from 0.3 g/cc - 1.6 g/cc. These SSs with known concentrations of Cs-134 and Cs-137 were then loaded onto trucks in

Design and Validation Testing of TruckScan to Assay Large Sacks of Fukushima Radioactive Debris on a Truck

International Nuclear Information System (INIS)

Suzuki, Atsuo; Bronson, Frazier

2015-01-01

As a result of the March 2011 earthquake and resulting tsunami in Japan, there was a serious accident at the Fukushima Dai-ichi Nuclear Power Plant. This accident has contaminated soil and vegetation in a wide area around the plant. Decontamination projects over the last 4 years have resulted in large numbers of 1 cubic meter canvas bags of debris, commonly called Super Sacks [SS]. These are currently stored nearby where they were generated, but starting in 2015, they will be moved to various Interim Storage Facilities [ISF]. Trucks will typically carry 8-20 of these SSs. When the trucks arrive at the ISF they need to be rapidly sorted into groups according to radioactivity level, for efficient subsequent processing. Canberra Industries, Inc. [CI] has designed a new truck monitoring system 'TruckScan' for use at these ISFs. The TruckScan system must measure the entire truck loaded with multiple closely packed SSs, and generate a nuclide specific assay report showing the radioactivity in each individual SS. The Canberra-Japan office, along with Obayashi Corporation have performed validation testing to demonstrate to the regulatory authorities that the proposed technique was sufficiently accurate. These validation tests were conducted at a temporary storage area in Fukushima prefecture. Decontaminated waste of various representative types and of various levels of radioactivity was gathered and mixed to create homogeneous volumes. These volumes were sampled multiple times and assayed with laboratory HPGe detectors to determine the reference concentration of each pile. Multiple SSs were loaded from each pile. Some of the SSs were filled 50% full, others 75% full, and others 100% full, to represent the typical loading configuration of the existing SSs in the field. The content of the SSs are either sand, soil, or vegetation with densities ranging from 0.3 g/cc - 1.6 g/cc. These SSs with known concentrations of Cs-134 and Cs-137 were then loaded onto trucks in

Development and Validation of a Real-Time PCR Assay for Rapid Detection of Candida auris from Surveillance Samples.

Science.gov (United States)

Leach, L; Zhu, Y; Chaturvedi, S

2018-02-01

Candida auris is an emerging multidrug-resistant yeast causing invasive health care-associated infection with high mortality worldwide. Rapid identification of C. auris is of primary importance for the implementation of public health measures to control the spread of infection. To achieve these goals, we developed and validated a TaqMan-based real-time PCR assay targeting the internal transcribed spacer 2 ( ITS 2) region of the ribosomal gene. The assay was highly specific, reproducible, and sensitive, with the detection limit of 1 C. auris CFU/PCR. The performance of the C. auris real-time PCR assay was evaluated by using 623 surveillance samples, including 365 patient swabs and 258 environmental sponges. Real-time PCR yielded positive results from 49 swab and 58 sponge samples, with 89% and 100% clinical sensitivity with regard to their respective culture-positive results. The real-time PCR also detected C. auris DNA from 1% and 12% of swab and sponge samples with culture-negative results, indicating the presence of dead or culture-impaired C. auris The real-time PCR yielded results within 4 h of sample processing, compared to 4 to 14 days for culture, reducing turnaround time significantly. The new real-time PCR assay allows for accurate and rapid screening of C. auris and can increase effective control and prevention of this emerging multidrug-resistant fungal pathogen in health care facilities. Copyright © 2018 Leach et al.

Ma2 antibodies: an evaluation of commercially available detection methods.

Science.gov (United States)

Johannis, Wibke; Renno, Joerg H; Wielckens, Klaus; Voltz, Raymond

2011-01-01

Ma2 antibodies belong to the onconeuronal antibodies which define a "definite" paraneoplastic neurological syndrome (PNS). Because of the clinical relevance, use of two separate methods (indirect immunofluorescence technique--IFT--and immunoblot) is advocated; however, with an increasing number of commercially available assay systems, usually only one assay is performed. We compared IFT and three commercially available immunoblots (ravo Diagnostika, Euroimmun, Milenia Biotec) on sera from 35 patients with clinically suspected PNS. 17 were Ma2 antibody associated as defined by consensus result (showing positive reactivity in 2 assays), 18 were Ma2 antibody negative controls. Sensitivity/specificity for single assays were for IFT 94%/94%, for ravo Diagnostika PNS blot 88%/100%, for Euroimmun Neuronal Antigens Profile blot 100%/89%, and for Milenia Biotec MTR blot 94%/100%. Our data confirm, although all tests performed well, a combination of 2 independent assays is still advisable for Ma2 antibody detection in order to achieve higher sensitivity and specificity rates.

Development and Validation of a Novel LC-MS/MS Opioid Confirmation Assay: Evaluation of β-glucuronidase Enzymes and Sample Cleanup Methods.

Science.gov (United States)

Yang, He S; Wu, Alan H B; Lynch, Kara L

2016-06-01

With the rise in the use and misuse of prescription opioids, there is an increasing need for the confirmed identification of opioid analgesics in toxicology laboratories. The goals of this study were to (i) systematically evaluate the hydrolysis efficiency of four β-glucuronidase enzymes under optimized condition; (ii) evaluate compound recovery, matrix effects and precision of three protein precipitation plates and (iii) develop and validate a qualitative liquid-chromatography mass spectrometry (LC-MS/MS) assay to identify 13 opioids in urine. A recombinant β-glucuronidase exhibited the best overall hydrolysis efficiency for seven opioid glucuronide conjugates compared with β-glucuronidase from red abalone, Escherichia coli and Patella vulgata One of the protein precipitation plates tested exhibited overall better recovery of the opioids and lower ion suppression compared with the other two plates. An ESI positive mode LC-MS/MS assay for qualitative opioid analysis was developed and validated. Linearity, LOD, precision, matrix effect, recovery, carryover and interference of the method were evaluated. Sixty-two patient samples were analyzed by both a legacy GC-MS opioid method and the LC-MS/MS method, and 22 samples were analyzed by the LC-MS/MS and an LC-MS/MS reference method. The results of the comparisons showed good concordance. Overall, we described an efficient sample preparation procedure for a sensitive qualitative opioid confirmation assay in urine. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Have you stress tested your assay?

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Zheng Cao

2016-08-01

Full Text Available Objectives: When a clinical assay is stressed with extraordinarily high volume of specimens over a short period of time, extra caution may be needed to avoid systematic errors and biases. Here we report our experience with a HgbA1c assay used for high volume wellness screening purpose, to illustrate the importance of stress testing during assay validation. Design and Methods: Over 15,000 whole blood specimens were tested for HgbA1c in a period of 2 months. HgbA1c was tested by an immunoturbidimetric method on a high through-put automation line. The HgbA1c population distribution in our study was compared to that from the NHANES database. Daily distributions of HgbA1c values ≥6%, means and medians were plotted. Correlation studies were performed between the high through-put immunoturbidimetric assay and a medium through-put HPLC method. Results: We observed a shift of HgbA1c distribution to the higher values compared to the NHANES. A bias of 15–20% was noted from further stress testing where large number of samples were batched and tested using the immunoturbidimetric assay. A 5–7% higher bias remained after implementing a cuvette washing program after each HgbA1c sample. We hypothesized this bias was caused by build-up of blood cell fragments in the cuvettes when continuous whole blood samples are run through the system. Our experience suggests stress testing needs to be incorporated early in the test validation process for high volume batched screening applications. This seemingly extra validation step may save significant troubleshooting and retesting efforts down the road. Keywords: Hemoglobin A1c, Immunoturbidimetric assay, HPLC, Quality assurance, Systematic bias, High volume, Automation

Rapid quantification of the latent reservoir for HIV-1 using a viral outgrowth assay.

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Gregory M Laird

Full Text Available HIV-1 persists in infected individuals in a stable pool of resting CD4(+ T cells as a latent but replication-competent provirus. This latent reservoir is the major barrier to the eradication of HIV-1. Clinical trials are currently underway investigating the effects of latency-disrupting compounds on the persistence of the latent reservoir in infected individuals. To accurately assess the effects of such compounds, accurate assays to measure the frequency of latently infected cells are essential. The development of a simpler assay for the latent reservoir has been identified as a major AIDS research priority. We report here the development and validation of a rapid viral outgrowth assay that quantifies the frequency of cells that can release replication-competent virus following cellular activation. This new assay utilizes bead and column-based purification of resting CD4(+ T cells from the peripheral blood of HIV-1 infected patients rather than cell sorting to obtain comparable resting CD4(+ T cell purity. This new assay also utilizes the MOLT-4/CCR5 cell line for viral expansion, producing statistically comparable measurements of the frequency of latent HIV-1 infection. Finally, this new assay employs a novel quantitative RT-PCR specific for polyadenylated HIV-1 RNA for virus detection, which we demonstrate is a more sensitive and cost-effective method to detect HIV-1 replication than expensive commercial ELISA detection methods. The reductions in both labor and cost make this assay suitable for quantifying the frequency of latently infected cells in clinical trials of HIV-1 eradication strategies.

Validation of FRET Assay for the Screening of Growth Inhibitors of Escherichia coli Reveals Elongasome Assembly Dynamics

Science.gov (United States)

van der Ploeg, René; Goudelis, Spyridon Theodoros; den Blaauwen, Tanneke

2015-01-01

The increase in antibiotic resistant bacteria demands the development of new antibiotics against preferably new targets. The common approach is to test compounds for their ability to kill bacteria or to design molecules that inhibit essential protein activities in vitro. In the first case, the mode of action of the drug is unknown and in the second case, it is not known whether the compound will pass the impermeable barrier of the bacterial envelope. We developed an assay that detects the target of a compound, as well as its ability to pass the membrane(s) simultaneously. The Escherichia coli cytoskeletal protein MreB recruits protein complexes (elongasomes) that are essential for cell envelope growth. An in cell Förster Resonance Energy Transfer (FRET) assay was developed to detect the interaction between MreB molecules and between MreB and the elongasome proteins RodZ, RodA and PBP2. Inhibition of the polymerization of MreB by S-(3,4-dichlorobenzyl) isothiourea (A22) or of the activity of PBP2 by mecilinam resulted in loss or reduction of all measured interactions. This suggests that the interactions between the elongasome proteins are governed by a combination of weak affinities and substrate availability. This validated in cell FRET assay can be used to screen for cell envelope growth inhibitors. PMID:26263980

Validation of FRET Assay for the Screening of Growth Inhibitors of Escherichia coli Reveals Elongasome Assembly Dynamics

Directory of Open Access Journals (Sweden)

René van der Ploeg

2015-07-01

Full Text Available The increase in antibiotic resistant bacteria demands the development of new antibiotics against preferably new targets. The common approach is to test compounds for their ability to kill bacteria or to design molecules that inhibit essential protein activities in vitro. In the first case, the mode of action of the drug is unknown and in the second case, it is not known whether the compound will pass the impermeable barrier of the bacterial envelope. We developed an assay that detects the target of a compound, as well as its ability to pass the membrane(s simultaneously. The Escherichia coli cytoskeletal protein MreB recruits protein complexes (elongasomes that are essential for cell envelope growth. An in cell Förster Resonance Energy Transfer (FRET assay was developed to detect the interaction between MreB molecules and between MreB and the elongasome proteins RodZ, RodA and PBP2. Inhibition of the polymerization of MreB by S-(3,4-dichlorobenzyl isothiourea (A22 or of the activity of PBP2 by mecilinam resulted in loss or reduction of all measured interactions. This suggests that the interactions between the elongasome proteins are governed by a combination of weak affinities and substrate availability. This validated in cell FRET assay can be used to screen for cell envelope growth inhibitors.

Prospective validation of an automated chemiluminescence-based assay of renin and aldosterone for the work-up of arterial hypertension.

Science.gov (United States)

Rossi, Gian Paolo; Ceolotto, Giulio; Rossitto, Giacomo; Seccia, Teresa Maria; Maiolino, Giuseppe; Berton, Chiara; Basso, Daniela; Plebani, Mario

2016-09-01

The availability of simple and accurate assays of plasma active renin (DRC) and aldosterone concentration (PAC) can improve the detection of secondary forms of arterial hypertension. Thus, we investigated the performance of an automated chemiluminescent assay for DRC and PAC in referred hypertensive patients. We prospectively recruited 260 consecutive hypertensive patients referred to an ESH Center for Hypertension. After exclusion of six protocol violations, 254 patients were analyzed: 67.3% had primary hypertension, 17.3% an aldosterone producing adenoma (APA), 11.4% idiopathic hyperaldosteronism (IHA), 2.4% renovascular hypertension (RVH), 0.8% familial hyperaldosteronism type 1 (FH-1), 0.4% apparent mineralocorticoid excess (AME), 0.4% a renin-producing tumor, and 3.9% were adrenalectomized APA patients. Bland-Altman plots and Deming regression were used to analyze results. The diagnostic accuracy (area under the curve, AUC of the ROC) of the DRC-based aldosterone-renin ratio (ARRCL) was compared with that of the PRA-based ARR (ARRRIA) using as reference the conclusive diagnosis of APA. At Bland-Altman plot, the DRC and PAC assay showed no bias as compared to the PRA and PAC assay. A tight relation was found between the DRC and the PRA values (concordance correlation coefficient=0.92, pAPA identification the AUC of the ARRCL was higher than that of the ARRRIA [0.974 (95% CI 0.940-0.991) vs. 0.894 (95% CI 0.841-0.933), p=0.02]. This rapid automated chemiluminescent DRC/PAC assay performed better than validated PRA/PAC radioimmunoassays for the identification of APA in referred hypertensive patients.

A High Throughput Screening Assay for Anti-Mycobacterial Small Molecules Based on Adenylate Kinase Release as a Reporter of Cell Lysis.

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Lauren Forbes

Full Text Available Mycobacterium tuberculosis (Mtb is well-established to be one of the most important bacterial pathogens for which new antimicrobial therapies are needed. Herein, we describe the development of a high throughput screening assay for the identification of molecules that are bactericidal against Mycobacteria. The assay utilizes the release of the intracellular enzyme adenylate kinase into the culture medium as a reporter of mycobacterial cell death. We demonstrate that the assay is selective for mycobactericidal molecules and detects anti-mycobacterial activity at concentrations below the minimum inhibitory concentration of many molecules. Thus, the AK assay is more sensitive than traditional growth assays. We have validated the AK assay in the HTS setting using the Mtb surrogate organism M. smegmatis and libraries of FDA approved drugs as well as a commercially available Diversity set. The screen of the FDA-approved library demonstrated that the AK assay is able to identify the vast majority of drugs with known mycobactericidal activity. Importantly, our screen of the Diversity set revealed that the increased sensitivity of the AK assay increases the ability of M. smegmatis-based screens to detect molecules with relatively poor activity against M. smegmatis but good to excellent activity against Mtb.

Performance and diagnostic usefulness of commercially available enzyme linked immunosorbent assay and rapid kits for detection of HIV, HBV and HCV in India

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Maity Susmita

2012-11-01

Full Text Available Abstract Background HIV, HBV and HCV pose a major public health problem throughout the world. Detection of infection markers for these agents is a major challenge for testing laboratories in a resource poor setting. As blood transfusion is an important activity saving millions of live every year, it also carries a risk of transfusion transmissible infections caused by these fatal blood borne pathogens if the quality of testing is compromised. Conventional ELISA is regarded as the mostly used screening technique but due to limitations like high cost, unavailability in many blood banks and testing sites, involvement of costly instruments, time taking nature and requirement of highly skilled personnel for interpretation, rapid tests are gaining more importance and warrants comparison of performance. Results A comparative study between these two techniques has been performed using commercially available diagnostic kits to assess their efficacy for detection of HIV, HBV and HCV infections. Rapid kits were more efficient in specificity with synthetic antigens along with high PPV than ELISA in most cases. Comparison between different ELISA kits revealed that Microlisa HIV and Hepalisa (J. Mitra & Co. Pvt. Ltd.; ERBA LISA HIV1 + 2, ERBA LISA Hepatitis B and ERBA LISA HCV (Transasia Bio-medicals Ltd. gives uniform result with good performance in terms of sensitivity, specificity, PPV, NPV and efficiency, whereas, Microlisa HCV (J. Mitra & Co. Pvt. Ltd., Microscreen HBsAg ELISA and INNOVA HCV (Span Diagnostics Ltd. did not perform well. Rapid kits were also having high degree of sensitivity and specificity (100% except in HIV Comb and HCV Comb (J. Mitra & Co. Pvt. Ltd.. The kit efficiency didn’t vary significantly among different companies and lots in all the cases except for HCV ELISA showing statistically significant variation (p  Conclusions ELISA is a good screening assay for markers of HIV, HBV and HCV infections. Rapid tests are useful for

Evaluation of the Thermo Scientific™ SureTect™ Listeria species Assay.

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Cloke, Jonathan; Evans, Katharine; Crabtree, David; Hughes, Annette; Simpson, Helen; Holopainen, Jani; Wickstrand, Nina; Kauppinen, Mikko

2014-03-01

The Thermo Scientific™ SureTect™ Listeria species Assay is a new real-time PCR assay for the detection of all species of Listeria in food and environmental samples. This validation study was conducted using the AOAC Research Institute (RI) Performance Tested MethodsSM program to validate the SureTect Listeria species Assay in comparison to the reference method detailed in International Organization for Standardization 11290-1:1996 including amendment 1:2004 in a variety of foods plus plastic and stainless steel. The food matrixes validated were smoked salmon, processed cheese, fresh bagged spinach, cantaloupe, cooked prawns, cooked sliced turkey meat, cooked sliced ham, salami, pork frankfurters, and raw ground beef. All matrixes were tested by Thermo Fisher Scientific, Microbiology Division, Basingstoke, UK. In addition, three matrixes (pork frankfurters, fresh bagged spinach, and stainless steel surface samples) were analyzed independently as part of the AOAC-RI-controlled independent laboratory study by the University of Guelph, Canada. Using probability of detection statistical analysis, a significant difference in favour of the SureTect assay was demonstrated between the SureTect and reference method for high level spiked samples of pork frankfurters, smoked salmon, cooked prawns, stainless steel, and low-spiked samples of salami. For all other matrixes, no significant difference was seen between the two methods during the study. Inclusivity testing was conducted with 68 different isolates of Listeria species, all of which were detected by the SureTect Listeria species Assay. None of the 33 exclusivity isolates were detected by the SureTect Listeria species Assay. Ruggedness testing was conducted to evaluate the performance of the assay with specific method deviations outside of the recommended parameters open to variation, which demonstrated that the assay gave reliable performance. Accelerated stability testing was additionally conducted, validating the

Field-Deployable Reverse Transcription-Insulated Isothermal PCR (RT-iiPCR) Assay for Rapid and Sensitive Detection of Foot-and-Mouth Disease Virus.

Science.gov (United States)

Ambagala, A; Fisher, M; Goolia, M; Nfon, C; Furukawa-Stoffer, T; Ortega Polo, R; Lung, O

2017-10-01

Foot-and-mouth disease (FMD) is a highly contagious viral disease of cloven-hoofed animals, which can decimate the livestock industry and economy of countries previously free of this disease. Rapid detection of foot-and-mouth disease virus (FMDV) is critical to containing an FMD outbreak. Availability of a rapid, highly sensitive and specific, yet simple and field-deployable assay would support local decision-making during an FMDV outbreak. Here we report validation of a novel reverse transcription-insulated isothermal PCR (RT-iiPCR) assay that can be performed on a commercially available, compact and portable POCKIT ™ analyser that automatically analyses data and displays '+' or '-' results. The FMDV RT-iiPCR assay targets the 3D region of the FMDV genome and was capable of detecting 9 copies of in vitro-transcribed RNA standard with 95% confidence. It accurately identified 63 FMDV strains belonging to all seven serotypes and showed no cross-reactivity with viruses causing similar clinical diseases in cloven-hoofed animals. The assay was able to identify FMDV RNA in multiple sample types including oral, nasal and lesion swabs, epithelial tissue suspensions, vesicular and oral fluid samples, even before the appearance of clinical signs. Clinical sensitivity of the assay was comparable or slightly higher than the laboratory-based real-time RT-PCR assay in use. The assay was able to detect FMDV RNA in vesicular fluid samples without nucleic acid extraction. For RNA extraction from more complex sample types, a commercially available taco ™ mini transportable magnetic bead-based, automated extraction system was used. This assay provides a potentially useful field-deployable diagnostic tool for rapid detection of FMDV in an outbreak in FMD-free countries or for routine diagnostics in endemic countries with less structured laboratory systems. © 2016 Her Majesty the Queen in Right of Canada.

Radon investigations - Soil and commercial projects

International Nuclear Information System (INIS)

Goodwin, R.W.

1987-01-01

The liability issues of radon exposure have prompted potential purchasers of vacant land for commercial/industrial development, and commercial landlords, renting large commercial buildings, to determine the radon gas levels at such sites. This paper deals with both pre-construction sites subject to freezing conditions and to large commercial structures. A correlation of radon gas levels within a commercial building and a sister pre-construction site confirms the validity of using activated charcoal canisters as a cost effective means to combating radon in large structures

Validity of a Commercial Linear Encoder to Estimate Bench Press 1 RM from the Force-Velocity Relationship

OpenAIRE

Bosquet, Laurent; Porta-Benache, Jeremy; Blais, Jérôme

2010-01-01

The aim of this study was to assess the validity and accuracy of a commercial linear encoder (Musclelab, Ergotest, Norway) to estimate Bench press 1 repetition maximum (1RM) from the force - velocity relationship. Twenty seven physical education students and teachers (5 women and 22 men) with a heterogeneous history of strength training participated in this study. They performed a 1 RM test and a force - velocity test using a Bench press lifting task in a random order. Mean 1 RM was 61.8 ± 15...

Assay strategies and methods for phospholipases

International Nuclear Information System (INIS)

Reynolds, L.J.; Washburn, W.N.; Deems, R.A.; Dennis, E.A.

1991-01-01

Of the general considerations discussed, the two issues which are most important in choosing an assay are (1) what sensitivity is required to assay a particular enzyme and (2) whether the assay must be continuous. One can narrow the options further by considering substrate availability, enzyme specificity, assay convenience, or the presence of incompatible side reactions. In addition, the specific preference of a particular phospholipase for polar head group, micellar versus vesicular substrates, and anionic versus nonionic detergents may further restrict the options. Of the many assays described in this chapter, several have limited applicability or serious drawbacks and are not commonly employed. The most commonly used phospholipase assays are the radioactive TLC assay and the pH-stat assay. The TLC assay is probably the most accurate, sensitive assay available. These aspects often outweigh the disadvantages of being discontinuous, tedious, and expensive. The radioactive E. coli assay has become popular recently as an alternative to the TLC assay for the purification of the mammalian nonpancreatic phospholipases. The assay is less time consuming and less expensive than the TLC assay, but it is not appropriate when careful kinetics are required. Where less sensitivity is needed, or when a continuous assay is necessary, the pH-stat assay is often employed. With purified enzymes, when free thiol groups are not present, a spectrophotometric thiol assay can be used. This assay is ∼ as sensitive as the pH-stat assay but is more convenient and more reproducible, although the substrate is not available commercially. Despite the many assay choices available, the search continues for a convenient, generally applicable assay that is both sensitive and continuous

Evaluation of two commercially available ELISA kits for the determination of melatonin concentrations in amniotic fluid throughout pregnancy.

Science.gov (United States)

Bagci, Soyhan; Altuntas, Özlem; Katzer, David; Berg, Christoph; Willruth, Arne; Reutter, Heiko; Bartmann, Peter; Müller, Andreas; Zur, Berndt

2017-01-01

Background The aim of the present study is to evaluate the utility of extraction versus non-extraction-based commercial melatonin ELISA kits for determining the melatonin concentration in amniotic fluid obtained in early and late pregnancy. Methods Pregnancy duration less than 28 weeks was defined as early and from 28 weeks until delivery as late gestation. Nine samples were obtained in early and 18 in late pregnancy. Two commercially available melatonin ELISA kits (melatonin ELISA RE54021, including methanol-based extraction and direct saliva melatonin ELISA RE 54041, not including an extraction step, both from IBL-International, Germany) were used to determine melatonin concentrations in amniotic fluid. Results The mean melatonin concentration in ELISAs assayed by the non-extraction was significantly lower than those assayed after extraction. Subgroup analysis showed that there was no significant difference between melatonin concentration measured by non-extraction versus extraction ELISA in early pregnancy (11.2 ± 7.4 vs. 12.2 ± 7.7, respectively, P = 0.463) but that the mean melatonin concentration in late pregnancy was significantly lower when assayed by non-extraction ELISA than when assayed by extraction ELISA (14.8 ± 9.3 vs. 145.1 ± 179.3, respectively; P pregnancy was rather poor (r 2  = 0.271, P = 0.022), as opposed to the good correlation found in early pregnancy (r 2  = 0.929, P melatonin assay without an extraction step, such as direct saliva ELISA, does not seem to be a valid method to determine the melatonin concentration of amniotic fluid, especially in late gestation.

Development and systematic validation of qPCR assays for rapid and reliable differentiation of Xylella fastidiosa strains causing citrus variegated chlorosis.

Science.gov (United States)

Li, Wenbin; Teixeira, Diva C; Hartung, John S; Huang, Qi; Duan, Yongping; Zhou, Lijuan; Chen, Jianchi; Lin, Hong; Lopes, Silvio; Ayres, A Juliano; Levy, Laurene

2013-01-01

The xylem-limited, Gram-negative, fastidious plant bacterium Xylella fastidiosa is the causal agent of citrus variegated chlorosis (CVC), a destructive disease affecting approximately half of the citrus plantations in the State of São Paulo, Brazil. The disease was recently found in Central America and is threatening the multi-billion U.S. citrus industry. Many strains of X. fastidiosa are pathogens or endophytes in various plants growing in the U.S., and some strains cross infect several host plants. In this study, a TaqMan-based assay targeting the 16S rDNA signature region was developed for the identification of X. fastidiosa at the species level. Another TaqMan-based assay was developed for the specific identification of the CVC strains. Both new assays have been systematically validated in comparison with the primer/probe sets from four previously published assays on one platform and under similar PCR conditions, and shown to be superior. The species specific assay detected all X. fastidiosa strains and did not amplify any other citrus pathogen or endophyte tested. The CVC-specific assay detected all CVC strains but did not amplify any non-CVC X. fastidiosa nor any other citrus pathogen or endophyte evaluated. Both sets were multiplexed with a reliable internal control assay targeting host plant DNA, and their diagnostic specificity and sensitivity remained unchanged. This internal control provides quality assurance for DNA extraction, performance of PCR reagents, platforms and operators. The limit of detection for both assays was equivalent to 2 to 10 cells of X. fastidiosa per reaction for field citrus samples. Petioles and midribs of symptomatic leaves of sweet orange harbored the highest populations of X. fastidiosa, providing the best materials for detection of the pathogen. These new species specific assay will be invaluable for molecular identification of X. fastidiosa at the species level, and the CVC specific assay will be very powerful for the

INDUCTION OF CYTOKINE PRODUCTION IN CHEETAH (ACINONYX JUBATUS) PERIPHERAL BLOOD MONONUCLEAR CELLS AND VALIDATION OF FELINE-SPECIFIC CYTOKINE ASSAYS FOR ANALYSIS OF CHEETAH SERUM.

Science.gov (United States)

Franklin, Ashley D; Crosier, Adrienne E; Vansandt, Lindsey M; Mattson, Elliot; Xiao, Zhengguo

2015-06-01

Peripheral blood mononuclear cells (PBMCs) were isolated from the whole blood of cheetahs (Acinonyx jubatus ; n=3) and stimulated with lipopolysaccharides (LPS) to induce the production of proinflammatory cytokines TNF-α, IL-1β, and IL-6 for establishment of cross-reactivity between these cheetah cytokines and feline-specific cytokine antibodies provided in commercially available Feline DuoSet® ELISA kits (R&D Systems, Inc., Minneapolis, Minnesota 55413, USA). This study found that feline-specific cytokine antibodies bind specifically to cheetah proinflammatory cytokines TNF-α, IL-1β, and IL-6 from cell culture supernatants. The assays also revealed that cheetah PBMCs produce a measurable, cell concentration-dependent increase in proinflammatory cytokine production after LPS stimulation. To enable the use of these kits, which are designed for cell culture supernatants for analyzing cytokine concentrations in cheetah serum, percent recovery and parallelism of feline cytokine standards in cheetah serum were also evaluated. Cytokine concentrations in cheetah serum were approximated based on the use of domestic cat standards in the absence of cheetah standard material. In all cases (for cytokines TNF-α, IL-1β, and IL-6), percent recovery increased as the serum sample dilution increased, though percent recovery varied between cytokines at a given dilution factor. A 1:2 dilution of serum resulted in approximately 45, 82, and 7% recovery of TNF-α, IL-1β, and IL-6 standards, respectively. Adequate parallelism was observed across a large range of cytokine concentrations for TNF-α and IL-1β; however, a significant departure from parallelism was observed between the IL-6 standard and the serum samples (P=0.004). Therefore, based on our results, the Feline DuoSet ELISA (R&D Systems, Inc.) kits are valid assays for the measurement of TNF-α and IL-1β in cheetah serum but should not be used for accurate measurement of IL-6.

Collaborative study for the validation of alternative in vitro potency assays for human tetanus immunoglobulins.

Science.gov (United States)

Gross, S; Janssen, S W J; de Vries, B; Terao, E; Daas, A; Buchheit, K-H

2010-07-01

An international collaborative study to validate 2 alternative in vitro methods for the potency testing of human tetanus immunoglobulin products was organised by the European Directorate for the Quality of Medicines & HealthCare (EDQM). The study, run in the framework of the Biological Standardisation Programme (BSP) under the aegis of the European Commission and the Council of Europe, involved 21 official medicines control and industry laboratories from 15 countries. Both methods, an enzyme-linked immunoassay (EIA) and a toxoid inhibition assay (TIA), showed good reproducibility, repeatability and precision. EIA and TIA discriminated between low, medium and high potency samples. Potency estimates correlated well and both values were in close agreement with those obtained by in vivo methods. Moreover, these alternative methods allowed to resolve discrepant results between laboratories that were due to product potency loss and reporting errors. The study demonstrated that EIA and TIA are suitable quality control methods for tetanus immunoglobulin, which can be standardised in a control laboratory using a quality assurance system. Consequently, the Group of Experts on Human Blood and Blood Products of the European Pharmacopoeia revised the monograph on human tetanus immunoglobulins to include both the methods as compendial alternatives to the in vivo mouse challenge assay. 2010 The International Association for Biologicals. Published by Elsevier Ltd. All rights reserved.

A deadenylase assay by size-exclusion chromatography.

Science.gov (United States)

He, Guang-Jun; Yan, Yong-Bin

2012-01-01

The shortening of the 3'-end poly(A) tail, also called deadenylation, is crucial to the regulation of mRNA processing, transportation, translation and degradation. The deadenylation process is achieved by deadenylases, which specifically catalyze the removal of the poly(A) tail at the 3'-end of eukaryotic mRNAs and release 5'-AMP as the product. To achieve their physiological functions, all deadenylases have numerous binding partners that may regulate their catalytic properties or recruit them into various protein complexes. To study the effects of various partners, it is important to develop new deadenylase assay that can be applied either in vivo or in vitro. In this research, we developed the deadenylase assay by the size-exclusion chromatography (SEC) method. The SEC analysis indicated that the poly(A) or oligo(A) substrate and the product AMP could be successfully separated and quantified. The enzymatic parameters of deadenylase could be obtained by quantifying the AMP generation. When using the commercial poly(A) as the substrate, a biphasic catalytic process was observed, which might correlate to the two distinct states of poly(A) in the commercial samples. Different lots of commercial poly(A) had dissimilar size distributions and were dissimilar in response to the degradation of deadenylase. The deadenylation pattern, processive or distributive, could also be investigated using the SEC assay by monitoring the status of the substrate and the generation kinetics of AMP and A2. The SEC assay was applicable to both simple samples using the purified enzyme and complex enzyme reaction conditions such as using protein mixtures or crude cell extracts as samples. The influence of solutes with absorption at 254 nm could be successfully eliminated by constructing the different SEC profiles.

Implementation of an Enzyme Linked Immunosorbent Assay for the Quantification of Allergenic Egg Residues in Red Wines Using Commercially Available Antibodies

Science.gov (United States)

Koestel, Carole; Simonin, Céline; Belcher, Sandrine

2016-01-01

Abstract Since the early 2000s, labeling of potentially allergenic food components to protect people who suffer from food allergies is compulsory in numerous industrialized countries. In Europe, milk and egg components used during the winemaking process must be indicated on the label since July 1, 2012. Several ELISA procedures have been developed to detect allergenic residues in wines. However, the complexity of the wine matrix can inhibit the immunoenzymatic reaction. The aim of this study was to implement an ELISA assay for the detection of ovalbumin in red wines using commercially available antibodies. The specificity of the acquired antibodies and the absence of cross reactivity were assessed by immunoblotting and ELISA. An ELISA assay with a LOD of 14.2 μg/L and a LOQ of 56.4 μg/L of ovalbumin in aqueous solution was obtained. Differences in ELISA signals were observed when analyzing various fining agents, although reproducible conformation of the antigen could be reached for the comparison of ovalbumin and Ovicolle. The differences between samples in terms of pH could be leveled but the inhibition of the ELISA signal, positively correlated to the tannin content of the wines, could not be suppressed. Thus, standard curves of ovalbumin in several wines were obtained by relative quantification. The control steps and the difficulties encountered presented in this study should be considered by anybody working toward the development of ELISA assays for the detection of allergenic residues in complex food matrices. PMID:27356183

Comparison of in-house and commercial real time-PCR based carbapenemase gene detection methods in Enterobacteriaceae and non-fermenting gram-negative bacterial isolates.

Science.gov (United States)

Smiljanic, M; Kaase, M; Ahmad-Nejad, P; Ghebremedhin, B

2017-07-10

Carbapenemase-producing gram-negative bacteria are increasing globally and have been associated with outbreaks in hospital settings. Thus, the accurate detection of these bacteria in infections is mandatory for administering the adequate therapy and infection control measures. This study aimed to establish and evaluate a multiplex real-time PCR assay for the simultaneous detection of carbapenemase gene variants in gram-negative rods and to compare the performance with a commercial RT-PCR assay (Check-Direct CPE). 116 carbapenem-resistant Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii isolates were genotyped for carbapenemase genes by PCR and sequencing. The defined isolates were used for the validation of the in-house RT-PCR by use of designed primer pairs and probes. Among the carbapenem-resistant isolates the genes bla KPC , bla VIM , bla NDM or bla OXA were detected. Both RT-PCR assays detected all bla KPC , bla VIM and bla NDM in the isolates. The in-house RT-PCR detected 53 of 67 (79.0%) whereas the commercial assay detected only 29 (43.3%) of the OXA genes. The in-house sufficiently distinguished the most prevalent OXA types (23-like and 48-like) in the melting curve analysis and direct detection of the genes from positive blood culture vials. The Check-Direct CPE and the in-house RT-PCR assay detected the carbapenem resistance from solid culture isolates. Moreover, the in-house assay enabled the identification of carbapenemase genes directly from positive blood-culture vials. However, we observed insufficient detection of various OXA genes in both assays. Nevertheless, the in-house RT-PCR detected the majority of the OXA type genes in Enterobacteriaceae and A. baumannii.

Direct 125I-radioligand assays for serum progesterone compared with assays involving extraction of serum

International Nuclear Information System (INIS)

Ratcliffe, W.A.; Corrie, J.E.T.; Dalziel, A.H.; Macpherson, J.S.

1982-01-01

Two direct radioimmunoassays for progesterone in 50 μL of unextracted serum or plasma with assays involving extraction of serum were compared. The direct assays include the use of either danazol at pH 7.4 or 8-anilino-1-naphthalenesulfonic acid at pH 4.0 to displace progesterone from serum binding-proteins. Progesterone is then assayed by using an antiserum to a progesterone 11α-hemisuccinyl conjugate and the radioligand 125 I-labeled progesterone 11α-glucuronyl tyramine, with separation by double-antibody techniques. Direct assays with either displacing agent gave good analytical recovery of progesterone added to human serum, and progesterone values for patients' specimens correlated well (r > 0.96) with results of assays involving extraction of serum. Precision was similar with each displacing agent over the working range 2.5-100 nmol/L and superior to that of extraction assays. We conclude that these direct assays of progesterone are analytically valid and more robust, precise, and technically convenient than many conventional methods involving extraction of serum

A molecular assay for sensitive detection of pathogen-specific T-cells.

Directory of Open Access Journals (Sweden)

Victoria O Kasprowicz

Full Text Available Here we describe the development and validation of a highly sensitive assay of antigen-specific IFN-γ production using real time quantitative PCR (qPCR for two reporters--monokine-induced by IFN-γ (MIG and the IFN-γ inducible protein-10 (IP10. We developed and validated the assay and applied it to the detection of CMV, HIV and Mycobacterium tuberculosis (MTB specific responses, in a cohort of HIV co-infected patients. We compared the sensitivity of this assay to that of the ex vivo RD1 (ESAT-6 and CFP-10-specific IFN-γ Elispot assay. We observed a clear quantitative correlation between the two assays (P<0.001. Our assay proved to be a sensitive assay for the detection of MTB-specific T cells, could be performed on whole blood samples of fingerprick (50 uL volumes, and was not affected by HIV-mediated immunosuppression. This assay platform is potentially of utility in diagnosis of infection in this and other clinical settings.

Development and validation of a quantitative PCR assay for Ichthyophonus spp.

Science.gov (United States)

White, Vanessa C; Morado, J Frank; Crosson, Lisa M; Vadopalas, Brent; Friedman, Carolyn S

2013-04-29

Members of the genus Ichthyophonus are trophically transmitted, cosmopolitan parasites that affect numerous fish species worldwide. A quantitative PCR (qPCR) assay specific for genus Ichthyophonus 18S ribosomal DNA was developed for parasite detection and surveillance. The new assay was tested for precision, repeatability, reproducibility, and both analytical sensitivity and specificity. Diagnostic sensitivity and specificity were estimated using tissue samples from a wild population of walleye pollock Theragra chalcogramma. Ichthyophonus sp. presence in tissue samples was determined by qPCR, conventional PCR (cPCR), and histology. Parasite prevalence estimates varied depending upon the detection method employed and tissue type tested. qPCR identified the greatest number of Ichthyophonus sp.-positive cases when applied to walleye pollock skeletal muscle. The qPCR assay proved sensitive and specific for Ichthyophonus spp. DNA, but like cPCR, is only a proxy for infection. When compared to cPCR, qPCR possesses added benefits of parasite DNA quantification and a 100-fold increase in analytical sensitivity. Because this novel assay is specific for known members of the genus, it is likely appropriate for detecting Ichthyophonus spp. DNA in various hosts from multiple regions. However, species-level identification and isotype variability would require DNA sequencing. In addition to distribution and prevalence applications, this assay could be modified and adapted for use with zooplankton or environmental samples. Such applications could aid in investigating alternate routes of transmission and life history strategies typical to members of the genus Ichthyophonus.

Development and Validation of a Novel Dual Luciferase Reporter Gene Assay to Quantify Ebola Virus VP24 Inhibition of IFN Signaling

Directory of Open Access Journals (Sweden)

Elisa Fanunza

2018-02-01

Full Text Available The interferon (IFN system is the first line of defense against viral infections. Evasion of IFN signaling by Ebola viral protein 24 (VP24 is a critical event in the pathogenesis of the infection and, hence, VP24 is a potential target for drug development. Since no drugs target VP24, the identification of molecules able to inhibit VP24, restoring and possibly enhancing the IFN response, is a goal of concern. Accordingly, we developed a dual signal firefly and Renilla luciferase cell-based drug screening assay able to quantify IFN-mediated induction of Interferon Stimulated Genes (ISGs and its inhibition by VP24. Human Embryonic Kidney 293T (HEK293T cells were transiently transfected with a luciferase reporter gene construct driven by the promoter of ISGs, Interferon-Stimulated Response Element (ISRE. Stimulation of cells with IFN-α activated the IFN cascade leading to the expression of ISRE. Cotransfection of cells with a plasmid expressing VP24 cloned from a virus isolated during the last 2014 outbreak led to the inhibition of ISRE transcription, quantified by a luminescent signal. To adapt this system to test a large number of compounds, we performed it in 96-well plates; optimized the assay analyzing different parameters; and validated the system by calculating the Z′- and Z-factor, which showed values of 0.62 and 0.53 for IFN-α stimulation assay and VP24 inhibition assay, respectively, indicative of robust assay performance.

Validity of a Commercial Linear Encoder to Estimate Bench Press 1 RM from the Force-Velocity Relationship.

Science.gov (United States)

Bosquet, Laurent; Porta-Benache, Jeremy; Blais, Jérôme

2010-01-01

The aim of this study was to assess the validity and accuracy of a commercial linear encoder (Musclelab, Ergotest, Norway) to estimate Bench press 1 repetition maximum (1RM) from the force - velocity relationship. Twenty seven physical education students and teachers (5 women and 22 men) with a heterogeneous history of strength training participated in this study. They performed a 1 RM test and a force - velocity test using a Bench press lifting task in a random order. Mean 1 RM was 61.8 ± 15.3 kg (range: 34 to 100 kg), while 1 RM estimated by the Musclelab's software from the force-velocity relationship was 56.4 ± 14.0 kg (range: 33 to 91 kg). Actual and estimated 1 RM were very highly correlated (r = 0.93, pvelocity relationship was a good measure for monitoring training induced adaptations, but also that it was not accurate enough to prescribe training intensities. Additional studies are required to determine whether accuracy is affected by age, sex or initial level. Key pointsSome commercial devices allow to estimate 1 RM from the force-velocity relationship.These estimations are valid. However, their accuracy is not high enough to be of practical help for training intensity prescription.Day-to-day reliability of force and velocity measured by the linear encoder has been shown to be very high, but the specific reliability of 1 RM estimated from the force-velocity relationship has to be determined before concluding to the usefulness of this approach in the monitoring of training induced adaptations.

Evaluation of five hepatitis delta virus marker assays for detection of antigen and antibody.

OpenAIRE

Bezeaud, A; Rosenswajg, M; Guillin, M C

1989-01-01

Five commercially available assays for hepatitis delta (HD) virus markers were compared for sensitivity, specificity, and reproducibility: three assays for antibody (anti-HD), provided by Diagnostics Pasteur, Organon Teknika, and Abbott Laboratories, and two assays for antigen (HD Ag), from Pasteur and Organon Teknika. The assay from Organon Teknika is the less sensitive assay for anti-HD detection. Although the sensitivities of the Pasteur and Abbott assays for anti-HD detection are similar,...

Investigation of sodium arsenite, thioacetamide, and diethanolamine in the alkaline comet assay: Part of the JaCVAM comet validation exercise.

Science.gov (United States)

Beevers, Carol; Henderson, Debbie; Lillford, Lucinda

2015-07-01

As part of the Japanese Center for the Validation of Alternative Methods (JaCVAM)-initiative international validation study of the in vivo rat alkaline comet assay (comet assay), we examined sodium arsenite, thioacetamide, and diethanolamine. Using the JaCVAM approved study protocol version 14.2, each chemical was tested in male rats up to maximum tolerated dose levels and DNA damage in the liver and stomach was assessed approximately 3h after the final administration by gavage. Histopathology assessments of liver and stomach sections from the same animals were also examined for evidence of cytotoxicity or necrosis. No evidence of DNA damage was observed in the stomach of animals treated with sodium arsenite at 7.5, 15, or 30 mg/kg/day. However, equivocal findings were found in the liver, where increases in DNA migration were observed in two independent experiments, but not in all treated animals and not at the same dose levels. Thioacetamide caused an increase in DNA migration in the stomach of rats treated at 19, 38, and 75 mg/kg/day, but not in the liver, despite evidence of marked hepatotoxicity following histopathology assessments. No evidence of DNA damage was observed in the stomach or liver of animals treated with diethanolamine at 175, 350, or 700 mg/kg/day. Copyright © 2015 Elsevier B.V. All rights reserved.

Advances in establishment and analysis of three-dimensional tumor spheroid-based functional assays for target validation and drug evaluation

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Vinci Maria

2012-03-01

Full Text Available Abstract Background There is overwhelming evidence that in vitro three-dimensional tumor cell cultures more accurately reflect the complex in vivo microenvironment than simple two-dimensional cell monolayers, not least with respect to gene expression profiles, signaling pathway activity and drug sensitivity. However, most currently available three-dimensional techniques are time consuming and/or lack reproducibility; thus standardized and rapid protocols are urgently needed. Results To address this requirement, we have developed a versatile toolkit of reproducible three-dimensional tumor spheroid models for dynamic, automated, quantitative imaging and analysis that are compatible with routine high-throughput preclinical studies. Not only do these microplate methods measure three-dimensional tumor growth, but they have also been significantly enhanced to facilitate a range of functional assays exemplifying additional key hallmarks of cancer, namely cell motility and matrix invasion. Moreover, mutual tissue invasion and angiogenesis is accommodated by coculturing tumor spheroids with murine embryoid bodies within which angiogenic differentiation occurs. Highly malignant human tumor cells were selected to exemplify therapeutic effects of three specific molecularly-targeted agents: PI-103 (phosphatidylinositol-3-kinase (PI3K-mammalian target of rapamycin (mTOR inhibitor, 17-N-allylamino-17-demethoxygeldanamycin (17-AAG (heat shock protein 90 (HSP90 inhibitor and CCT130234 (in-house phospholipase C (PLCγ inhibitor. Fully automated analysis using a Celigo cytometer was validated for tumor spheroid growth and invasion against standard image analysis techniques, with excellent reproducibility and significantly increased throughput. In addition, we discovered key differential sensitivities to targeted agents between two-dimensional and three-dimensional cultures, and also demonstrated enhanced potency of some agents against cell migration

Cross-reactivity of antibodies with phenolic compounds in pistachios during quantification of ochratoxin A by commercial enzyme-linked immunosorbent assay kits.

Science.gov (United States)

Lee, Hyun Jung; Meldrum, Alexander D; Rivera, Nicholas; Ryu, Dojin

2014-10-01

Ochratoxin A (OTA), a nephrotoxic mycotoxin, naturally occurs in wide range of agricultural commodities. Typical screening of OTA involves various enzyme-linked immunosorbent assay (ELISA) methods. Pistachio (Pistacia vera L.) is a rich source of phenolic compounds that may result in a false positive due to structural similarities to OTA. The present study investigated the cross-reactivity profiles of phenolic compounds using two commercial ELISA test kits. High-performance liquid chromatography was used to confirm the concentration of OTA in the pistachio samples and compared with the results obtained from ELISA. When the degree of interaction and 50 % inhibitory concentration of phenolic compounds were determined, the cross-reactivity showed a pattern similar to that observed with the commercial ELSIA kits, although quantitatively different. In addition, the degree of interaction increased with the increasing concentration of phenolic compounds. The ELISA value had stronger correlations with the content of total phenolic compound, gallic acid, and catechin (R(2) = 0.757, 0.732, and 0.729, respectively) compared with epicatechin (R(2) = 0.590). These results suggest that phenolic compounds in pistachio skins may cross-react with the OTA antibody and lead to a false positive or to an overestimation of OTA concentration in ELISA-based tests.

Implementation of an Enzyme Linked Immunosorbent Assay for the Quantification of Allergenic Egg Residues in Red Wines Using Commercially Available Antibodies.

Science.gov (United States)

Koestel, Carole; Simonin, Céline; Belcher, Sandrine; Rösti, Johannes

2016-08-01

Since the early 2000s, labeling of potentially allergenic food components to protect people who suffer from food allergies is compulsory in numerous industrialized countries. In Europe, milk and egg components used during the winemaking process must be indicated on the label since July 1, 2012. Several ELISA procedures have been developed to detect allergenic residues in wines. However, the complexity of the wine matrix can inhibit the immunoenzymatic reaction. The aim of this study was to implement an ELISA assay for the detection of ovalbumin in red wines using commercially available antibodies. The specificity of the acquired antibodies and the absence of cross reactivity were assessed by immunoblotting and ELISA. An ELISA assay with a LOD of 14.2 μg/L and a LOQ of 56.4 μg/L of ovalbumin in aqueous solution was obtained. Differences in ELISA signals were observed when analyzing various fining agents, although reproducible conformation of the antigen could be reached for the comparison of ovalbumin and Ovicolle. The differences between samples in terms of pH could be leveled but the inhibition of the ELISA signal, positively correlated to the tannin content of the wines, could not be suppressed. Thus, standard curves of ovalbumin in several wines were obtained by relative quantification. The control steps and the difficulties encountered presented in this study should be considered by anybody working toward the development of ELISA assays for the detection of allergenic residues in complex food matrices. © 2016 The Authors. Journal of Food Science published by Wiley Periodicals, Inc. on behalf of Institute of Food Technologists.

An Assay in Microtitre Plates for Absolute Abundance of Chicken Interferon Alpha Transcripts

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Renata Novak Kujundžić

2010-01-01

Full Text Available Immunosuppression of commercial chickens is a serious animal health and economic problem in the poultry industry. The major causes of the immunosuppression are viruses that suppress transcription of interferon genes, especially interferon alpha. There is a need for monitoring immunosuppression in commercially bred chickens. For this purpose, the absolute abundance of interferon alpha transcripts can be measured in blood of chickens by a suitable assay. Such an assay was used to estimate abundance of chicken interferon alpha in a sample of splenic cells induced with polyinosinic polycytidylic acid. The abundance measured was 29 ± 2 attomoles/µg total RNA. This assay can be performed in microtitre plates using samples collected from chickens in poultry houses.

Evaluation of the Thermo Scientific™ SureTect™ Salmonella species Assay.

Science.gov (United States)

Cloke, Jonathan; Clark, Dorn; Radcliff, Roy; Leon-Velarde, Carlos; Larson, Nathan; Dave, Keron; Evans, Katharine; Crabtree, David; Hughes, Annette; Simpson, Helen; Holopainen, Jani; Wickstrand, Nina; Kauppinen, Mikko

2014-03-01

The Thermo Scientific™ SureTect™ Salmonella species Assay is a new real-time PCR assay for the detection of Salmonellae in food and environmental samples. This validation study was conducted using the AOAC Research Institute (RI) Performance Tested MethodsSM program to validate the SureTect Salmonella species Assay in comparison to the reference method detailed in International Organization for Standardization 6579:2002 in a variety of food matrixes, namely, raw ground beef, raw chicken breast, raw ground pork, fresh bagged lettuce, pork frankfurters, nonfat dried milk powder, cooked peeled shrimp, pasteurized liquid whole egg, ready-to-eat meal containing beef, and stainless steel surface samples. With the exception of liquid whole egg and fresh bagged lettuce, which were tested in-house, all matrixes were tested by Marshfield Food Safety, Marshfield, WI, on behalf of Thermo Fisher Scientific. In addition, three matrixes (pork frankfurters, lettuce, and stainless steel surface samples) were analyzed independently as part of the AOAC-RI-controlled laboratory study by the University of Guelph, Canada. No significant difference by probability of detection or McNemars Chi-squared statistical analysis was found between the candidate or reference methods for any of the food matrixes or environmental surface samples tested during the validation study. Inclusivity and exclusivity testing was conducted with 117 and 36 isolates, respectively, which demonstrated that the SureTect Salmonella species Assay was able to detect all the major groups of Salmonella enterica subspecies enterica (e.g., Typhimurium) and the less common subspecies of S. enterica (e.g., arizoniae) and the rarely encountered S. bongori. None of the exclusivity isolates analyzed were detected by the SureTect Salmonella species Assay. Ruggedness testing was conducted to evaluate the performance of the assay with specific method deviations outside of the recommended parameters open to variation

Who and How: Comprehensive RNA-Based BodyfluID Assay to Provide Context to a Recovered DNA Profile

Science.gov (United States)

2015-08-25

capillary electrophoresis (CE) and high resolution melt ( HRM ) assays 3 were developed and fully validated. The results of this study demonstrate...Multiplex High Resolution Melt ( HRM ) Assays ................................ 11  D. Developmental Validation of the CE and HRM Assays...Sequences (Top) and Primer Mix Composition (Bottom) for the Blood-Menstrual Blood HRM Assay

In Vitro Dissolution Profile of Dapagliflozin: Development, Method Validation, and Analysis of Commercial Tablets

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Rafaela Zielinski Cavalheiro de Meira

2017-01-01

Full Text Available Dapagliflozin was the first of its class (inhibitors of sodium-glucose cotransporter to be approved in Europe, USA, and Brazil. As the drug was recently approved, there is the need for research on analytical methods, including dissolution studies for the quality evaluation and assurance of tablets. The dissolution methodology was developed with apparatus II (paddle in 900 mL of medium (simulated gastric fluid, pH 1.2, temperature set at 37±0.5°C, and stirring speed of 50 rpm. For the quantification, a spectrophotometric (λ=224 nm method was developed and validated. In validation studies, the method proved to be specific and linear in the range from 0.5 to 15 μg·mL−1 (r2=0.998. The precision showed results with RSD values lower than 2%. The recovery of 80.72, 98.47, and 119.41% proved the accuracy of the method. Through a systematic approach by applying Factorial 23, the robustness of the method was confirmed (p>0.05. The studies of commercial tablets containing 5 or 10 mg demonstrated that they could be considered similar through f1, f2, and dissolution efficiency analyses. Also, the developed method can be used for the quality evaluation of dapagliflozin tablets and can be considered as a scientific basis for future official pharmacopoeial methods.

An European inter-laboratory validation of alternative endpoints of the murine local lymph node assay: 2nd round.

Science.gov (United States)

Ehling, G; Hecht, M; Heusener, A; Huesler, J; Gamer, A O; van Loveren, H; Maurer, Th; Riecke, K; Ullmann, L; Ulrich, P; Vandebriel, R; Vohr, H-W

2005-08-15

The original local lymph node assay (LLNA) is based on the use of radioactive labelling to measure cell proliferation. Other endpoints for the assessment of proliferation are also authorized by the OECD Guideline 429 provided there is appropriate scientific support, including full citations and description of the methodology (OECD, 2002. OECD Guideline for the Testing of Chemicals; Skin Sensitization: Local Lymph Node Assay, Guideline 429. Paris, adopted 24th April 2002.). Here, we describe the outcome of the second round of an inter-laboratory validation of alternative endpoints in the LLNA conducted in nine laboratories in Europe. The validation study was managed and supervised by the Swiss Agency for Therapeutic Products (Swissmedic) in Bern. Ear-draining lymph node (LN) weight and cell counts were used to assess LN cell proliferation instead of [3H]TdR incorporation. In addition, the acute inflammatory skin reaction was measured by ear weight determination of circular biopsies of the ears to identify skin irritation properties of the test items. The statistical analysis was performed in the department of statistics at the university of Bern. Similar to the EC(3) values defined for the radioactive method, threshold values were calculated for the endpoints measured in this modification of the LLNA. It was concluded that all parameters measured have to be taken into consideration for the categorisation of compounds due to their sensitising potencies. Therefore, an assessment scheme has been developed which turned out to be of great importance to consistently assess sensitisation versus irritancy based on the data of the different parameters. In contrast to the radioactive method, irritants have been picked up by all the laboratories applying this assessment scheme.

Performance of a Multiplex Serological Helicobacter pylori Assay on a Novel Microfluidic Assay Platform

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Angela Filomena

2017-10-01

Full Text Available Infection with Helicobacter pylori (H. pylori occurs in 50% of the world population, and is associated with the development of ulcer and gastric cancer. Serological diagnostic tests indicate an H. pylori infection by detecting antibodies directed against H. pylori proteins. In addition to line blots, multiplex assay platforms provide smart solutions for the simultaneous analysis of antibody responses towards several H. pylori proteins. We used seven H. pylori proteins (FliD, gGT, GroEL, HpaA, CagA, VacA, and HP0231 and an H. pylori lysate for the development of a multiplex serological assay on a novel microfluidic platform. The reaction limited binding regime in the microfluidic channels allows for a short incubation time of 35 min. The developed assay showed very high sensitivity (99% and specificity (100%. Besides sensitivity and specificity, the technical validation (intra-assay CV = 3.7 ± 1.2% and inter-assay CV = 5.5 ± 1.2% demonstrates that our assay is also a robust tool for the analysis of the H. pylori-specific antibody response. The integration of the virulence factors CagA and VacA allow for the assessment of the risk for gastric cancer development. The short assay time and the performance of the platform shows the potential for implementation of such assays in a clinical setting.

Use of Molecular Assays in Diagnosis and Monitoring of Cytomegalovirus Disease following Renal Transplantation

OpenAIRE

Aitken, Celia; Barrett-Muir, Winsome; Millar, Colin; Templeton, Kate; Thomas, Janice; Sheridan, Fran; Jeffries, Donald; Yaqoob, Magdi; Breuer, Judith

1999-01-01

We compared two commercial molecular assays (the Murex Hybrid Capture CMV DNA assay [HCA], version 2, and the Roche Amplicor plasma PCR assay) with a standard shell vial assay in detecting and predicting cytomegalovirus (CMV) disease in a group of renal transplant patients and assessed the role of viral load measurements (using the HCA) in their management. The sensitivity of the HCA and Amplicor assay in terms of disease detection was 100%, compared to 71% for the shell vial assay. Both the ...

Applicability of Commercially Available ELISA Kits for the Quantification of Faecal Immunoreactive Corticosterone Metabolites in Mice

DEFF Research Database (Denmark)

Abelson, Klas S P; Kalliokoski, Otto; Teilmann, Anne Charlotte

2016-01-01

Background: Commercially available ELISA kits are popular among investigators that quantify faecal corticosterone or cortisol metabolites (FCM) for stress assessment in animals. However, in faeces, these assays mainly detect immunoreactive glucocorticoid metabolites. Since different assays contain......: The present study was designed to investigate corticosterone (CORT) in serum and FCM levels in faeces of laboratory mice, as quantified in four different ELISA kits (DRG EIA-4164, Demeditec DEV9922, Enzo ADI-900-097 and Cayman EIA kit 500655). Assay kits were chosen based on the origin of the antibody...... assays, in both groups of mice. In faecal samples, there was no consistent positive correlation between the levels detected in the four assays and the measured concentration of FCM also differed between assays. Conclusion: Whereas commercially available CORT ELISAs are frequently successfully used...

Assay development status report for total cyanide

International Nuclear Information System (INIS)

Simpson, B.C.; Jones, T.E.; Pool, K.H.

1993-02-01

A validated cyanide assay that is applicable to a variety of tank waste matrices is necessary to resolve certain waste tank safety issues and for purposes of overall waste characterization. The target for this effort is an assay with an applicable range of greater than 1,000 ppM (0.10 wt%) total cyanide and a confidence level greater than 80%. Figure 1 illustrates the operating regime of the proposed cyanide assay method. The Assay Development Status Report for Total Cyanide will summarize the past experience with cyanide analyses on-tank waste matrices and will rate the status of the analytical methods used to assay total cyanide (CN - ion) in the tank waste matrices as acceptable or unacceptable. This paper will also briefly describe the current efforts for improving analytical resolution of the assays and the attempts at speciation

Evaluation of automated assays for immunoglobulin G, M, and A measurements in dog and cat serum.

Science.gov (United States)

Tvarijonaviciute, Asta; Martínez-Subiela, Silvia; Caldin, Marco; Tecles, Fernando; Ceron, Jose J

2013-09-01

Measurements of immunoglobulins (Igs) in companion animals can be useful to detect deficiencies of the humoral immune system, that can be associated with opportunistic or chronic infections, or other immune-mediated disorders including B-cell neoplasms. The purpose of this study was to evaluate commercially available automated immunoturbidimetric assays designed for human IgG, M, and A measurements in canine and feline serum using species-specific calibrators. Canine and feline serum samples with different IgG, M, and A concentrations were used for the analytical validation of the assays. Intra- and inter-assay precision, linearity under dilution, spiking recovery, and limit of detection were determined. In addition, effects of lipemia, hemolysis, and bilirubinemia were evaluated. Finally, Ig concentrations were determined in small groups of diseased dogs and cats, and compared with healthy groups. Spiking recovery and linearity under dilution tests showed that the assays measured Igs in canine and feline serum samples precisely and accurately. Intra- and inter-assay imprecisions were lower than 15% in all cases. Significantly higher IgG, IgM, and IgA levels were observed in dogs with leishmaniasis, while dogs with pyometra showed a statistically significant increase in IgM and IgA concentrations in comparison with healthy dogs. Significantly higher IgG and IgM levels were observed in FIV-infected cats compared with healthy ones. The automated human Ig assays showed adequate precision and accuracy with serum samples from dogs and cats. Also, they were able to discriminate different concentrations of Igs in healthy and diseased animals. © 2013 American Society for Veterinary Clinical Pathology.

A commercial ELISA detects high levels of human H5 antibody but cross-reacts with influenza A antibodies.

Science.gov (United States)

Stelzer-Braid, Sacha; Wong, Bruce; Robertson, Peter; Lynch, Garry W; Laurie, Karen; Shaw, Robert; Barr, Ian; Selleck, Paul W; Baleriola, Cristina; Escott, Ros; Katsoulotos, Gregory; Rawlinson, William D

2008-10-01

Commercial serological assays to determine influenza A H5N1 infection are available, although the accuracy and reproducibility of these are not reported in detail. This study aimed to assess the validity of a commercial ELISA H5 hemagglutinin (HA) antibody kit. A commercial ELISA for detection of antibodies towards influenza A H5 HA was evaluated using human sera from vaccinated individuals. The ELISA was used to screen 304 sera with elevated influenza A complement fixation titres collected between the period 1995-2007. The ELISA was found to be accurate for sera with high levels of anti-H5 antibodies, and would be useful in clinical settings where a rapid result is required. Thirteen of the stored sera were positive using the ELISA, but were confirmed as negative for H5N1 exposure using further serological tests. Absorption studies suggested that antibodies towards seasonal H3N2 and H1N1 influenza may cross-react with H5 antigen, giving false positive results with the ELISA.

Prospective Validation of a 21-Gene Expression Assay in Breast Cancer.

Science.gov (United States)

Sparano, Joseph A; Gray, Robert J; Makower, Della F; Pritchard, Kathleen I; Albain, Kathy S; Hayes, Daniel F; Geyer, Charles E; Dees, Elizabeth C; Perez, Edith A; Olson, John A; Zujewski, JoAnne; Lively, Tracy; Badve, Sunil S; Saphner, Thomas J; Wagner, Lynne I; Whelan, Timothy J; Ellis, Matthew J; Paik, Soonmyung; Wood, William C; Ravdin, Peter; Keane, Maccon M; Gomez Moreno, Henry L; Reddy, Pavan S; Goggins, Timothy F; Mayer, Ingrid A; Brufsky, Adam M; Toppmeyer, Deborah L; Kaklamani, Virginia G; Atkins, James N; Berenberg, Jeffrey L; Sledge, George W

2015-11-19

Prior studies with the use of a prospective-retrospective design including archival tumor samples have shown that gene-expression assays provide clinically useful prognostic information. However, a prospectively conducted study in a uniformly treated population provides the highest level of evidence supporting the clinical validity and usefulness of a biomarker. We performed a prospective trial involving women with hormone-receptor-positive, human epidermal growth factor receptor type 2 (HER2)-negative, axillary node-negative breast cancer with tumors of 1.1 to 5.0 cm in the greatest dimension (or 0.6 to 1.0 cm in the greatest dimension and intermediate or high tumor grade) who met established guidelines for the consideration of adjuvant chemotherapy on the basis of clinicopathologic features. A reverse-transcriptase-polymerase-chain-reaction assay of 21 genes was performed on the paraffin-embedded tumor tissue, and the results were used to calculate a score indicating the risk of breast-cancer recurrence; patients were assigned to receive endocrine therapy without chemotherapy if they had a recurrence score of 0 to 10, indicating a very low risk of recurrence (on a scale of 0 to 100, with higher scores indicating a greater risk of recurrence). Of the 10,253 eligible women enrolled, 1626 women (15.9%) who had a recurrence score of 0 to 10 were assigned to receive endocrine therapy alone without chemotherapy. At 5 years, in this patient population, the rate of invasive disease-free survival was 93.8% (95% confidence interval [CI], 92.4 to 94.9), the rate of freedom from recurrence of breast cancer at a distant site was 99.3% (95% CI, 98.7 to 99.6), the rate of freedom from recurrence of breast cancer at a distant or local-regional site was 98.7% (95% CI, 97.9 to 99.2), and the rate of overall survival was 98.0% (95% CI, 97.1 to 98.6). Among patients with hormone-receptor-positive, HER2-negative, axillary node-negative breast cancer who met established guidelines for

A Fluorescent Assay for Plant Caffeic Acid O-methyltransferases

Science.gov (United States)

We have developed a facile, sensitive and continuous assay to measure the activities of plant COMTs using s-adenosyl homocysteine hydrolase as a coupling enzyme and and adeonsine a thiol-specific fluor, Thioglo1, as the detecting reagent. This assay was validated using recombinant sorghum COMT (BMR-...

Development and validation of a dried blood spot assay for the quantification of ribavirin using liquid chromatography coupled to mass spectrometry

Science.gov (United States)

Jimmerson, Leah C.; Zheng, Jia-Hua; Bushman, Lane R.; MacBrayne, Christine E.; Anderson, Peter L.; Kiser, Jennifer J.

2014-01-01

Efficient, inexpensive and sensitive assays for the measurement of drugs are of interest for pharmacokinetic and pharmacodynamics (PK-PD) analysis. Dried blood spots (DBS) are a unique bioanaltyical matrix with the potential to fulfill this interest for the measurement of numerous analytes. Here we describe the development and validation of a reversed-phase high performance liquid chromatographic (LC), tandem mass spectrometry (MS/MS) assay for the determination of ribavirin (RBV) in DBS. A 3mm punch from spotted and dried whole blood was extracted in methanol utilizing isotopically labeled internal standard for LC-MS/MS analysis. Validation was performed over a range of 0.05 μg/mL to 10.0 μg/mL and the method was shown to be precise (coefficient of variation ≤ 15%) and accurate (within ±15% of control). These acceptance criteria were met for hematocrit ranges of 20-54%, for center versus edge punches and for spot volumes from 10-60 μL. RBV was stable for up to 140 days at room temperature and −20°C as well as for three freeze/thaw cycles. Correlation of RBV in DBS versus in plasma yielded r2 ≥ 0.98 demonstrating that DBS can be used as an alternative to plasma for PK-PD studies in human subjects. PMID:24291608

Battery operated preconcentration-assisted lateral flow assay.

Science.gov (United States)

Kim, Cheonjung; Yoo, Yong Kyoung; Han, Sung Il; Lee, Junwoo; Lee, Dohwan; Lee, Kyungjae; Hwang, Kyo Seon; Lee, Kyu Hyoung; Chung, Seok; Lee, Jeong Hoon

2017-07-11

Paper-based analytical devices (e.g. lateral flow assays) are highly advantageous as portable diagnostic systems owing to their low costs and ease of use. Because of their low sensitivity and detection limits for biomolecules, these devices have several limitations in applications for real-field diagnosis. Here, we demonstrate a paper-based preconcentration enhanced lateral flow assay using a commercial β-hCG-based test. Utilizing a simple 9 V battery operation with a low power consumption of approximately 81 μW, we acquire a 25-fold preconcentration factor, demonstrating a clear sensitivity enhancement in the colorimetric lateral flow assay; consequently, clear colors are observed in a rapid kit test line, which cannot be monitored without preconcentration. This device can also facilitate a semi-quantitative platform using the saturation value and/or color intensity in both paper-based colorimetric assays and smartphone-based diagnostics.

Radioimmunoassay of human homologous prolactin in serum with commercially available reagents

International Nuclear Information System (INIS)

Kao, P.C.; Jiang, N.S.; Abboud, C.F.

1977-01-01

A clinically useful and reproducible radioimmunoassay for human homologous prolactin, established with commercially available reagents, was studied and validated. We present detailed conditions for iodination and purification of labeled prolactin and the optimal conditions for the assay. By the method, we found values (μg/liter) as follows for serum prolactin: normal men, 8.9 +- 5.2 (mean +- SD); normal women, 11.8 +- 5.5; normal women taking contraceptive pills, 9.2 +- 5.0; pregnant women in the third trimester, 188 +- 69.5; patients with various diseases other than of the hypothalamic-pituitary axis, 9.3 +- 6.3; in some patients with amenorrhea and galactorrhea of diverse origin, 78.2 +- 87.4; and in some patients with surgically proven pituitary tumor, 1414 +- 1980. Results under provocative testing are also presented for a patient with normal hypothalamic-pituitary function

Development of Rapid Isothermal Amplification Assays for Detection of Phytophthora spp. in Plant Tissue.

Science.gov (United States)

Miles, Timothy D; Martin, Frank N; Coffey, Michael D

2015-02-01

Several isothermal amplification techniques recently have been developed that are tolerant of inhibitors present in many plant extracts, which can reduce the need for obtaining purified DNA for running diagnostic assays. One such commercially available technique that has similarities with real-time polymerase chain reaction (PCR) for designing primers and a labeled probe is recombinase polymerase amplification (RPA). This technology was used to develop two simple and rapid approaches for detection of Phytophthora spp.: one genus-specific assay multiplexed with a plant internal control and the other species-specific assays for Phytophthora ramorum and P. kernoviae. All assays were tested for sensitivity (ranging from 3 ng to 1 fg of DNA) and specificity using DNA extracted from more than 136 Phytophthora taxa, 21 Pythium spp., 1 Phytopythium sp., and a wide range of plant species. The lower limit of linear detection using purified DNA was 200 to 300 fg of DNA in all pathogen RPA assays. Six different extraction buffers were tested for use during plant tissue maceration and the assays were validated in the field by collecting 222 symptomatic plant samples from over 50 different hosts. Only 56 samples were culture positive for Phytophthora spp. whereas 91 were positive using the Phytophthora genus-specific RPA test and a TaqMan real-time PCR assay. A technique for the generation of sequencing templates from positive RPA amplifications to confirm species identification was also developed. These RPA assays have added benefits over traditional technologies because they are rapid (results can be obtained in as little as 15 min), do not require DNA extraction or extensive training to complete, use less expensive portable equipment than PCR-based assays, and are significantly more specific than current immunologically based methods. This should provide a rapid, field-deployable capability for pathogen detection that will facilitate point-of-sample collection processing

Results of the International Validation of the in vivo rodent alkaline comet assay for the detection of genotoxic carcinogens: Individual data for 1,2-dibromoethane, p-anisidine, and o-anthranilic acid in the 2nd step of the 4th phase Validation Study under the JaCVAM initiative.

Science.gov (United States)

Takasawa, Hironao; Takashima, Rie; Narumi, Kazunori; Kawasako, Kazufumi; Hattori, Akiko; Kawabata, Masayoshi; Hamada, Shuichi

2015-07-01

As part of the Japanese Center for the Validation of Alternative Methods (JaCVAM)-initiative International Validation Study of an in vivo rat alkaline comet assay, we examined 1,2-dibromoethane (DBE), p-anisidine (ASD), and o-anthranilic acid (ANT) to investigate the effectiveness of the comet assay in detecting genotoxic carcinogens. Each of the three test chemicals was administered to 5 male Sprague-Dawley rats per group by oral gavage at 48, 24, and 3h before specimen preparation. Single cells were collected from the liver and glandular stomach at 3h after the final dosing, and the specimens prepared from these two organs were subjected to electrophoresis under alkaline conditions (pH>13). The percentage of DNA intensity in the comet tail was then assessed using an image analysis system. A micronucleus (MN) assay was also conducted using these three test chemicals with the bone marrow (BM) cells collected from the same animals simultaneously used in the comet assay, i.e., combination study of the comet assay and BM MN assay. A genotoxic (Ames positive) rodent carcinogen, DBE gave a positive result in the comet assay in the present study, while a genotoxic (Ames positive) non-carcinogen, ASD and a non-genotoxic (Ames negative) non-carcinogen, ANT showed negative results in the comet assay. All three chemicals produced negative results in the BM MN assay. While the comet assay findings in the present study were consistent with those obtained from the rodent carcinogenicity studies for the three test chemicals, we consider the positive result in the comet assay for DBE to be particularly meaningful, given that this chemical produced a negative result in the BM MN assay. Therefore, the combination study of the comet assay and BM MN assay is a useful method to detect genotoxic carcinogens that are undetectable with the BM MN assay alone. Copyright © 2015 Elsevier B.V. All rights reserved.

Differential Detection of Human Papillomavirus Genotypes and Cervical Intraepithelial Neoplasia by Four Commercial Assays

DEFF Research Database (Denmark)

Rebolj, Matejka; Bonde, Jesper; Preisler, Sarah

2016-01-01

intraepithelial neoplasia (CIN) in 2.5 years after the baseline testing were determined from the national pathology register. HPV-positive women undergoing primary screening having concordant samples were more likely to harbor high-risk infections and less likely to harbor only low-risk infections than women......Laboratories can nowadays choose from >100 Human Papillomavirus (HPV) assays for cervical screening. Our previous analysis based on the data from the Danish Horizon study, however, showed that four widely used assays, Hybrid Capture 2 (HC2), cobas, CLART and APTIMA, frequently do not detect...... the same HPV infections. Here, we determined the characteristics of the concordant (all four assays returning a positive HPV test result) and discordant samples (all other HPV-positive samples) in primary cervical screening at 30-65 years (n=2859) and in a concurrent referral population from the same...

Content of Asthmagen Natural Rubber Latex Allergens in Commercial Disposable Gloves.

Science.gov (United States)

Bittner, C; Garrido, M V; Krach, L H; Harth, V

The use of natural rubber latex (NRL) gloves in many occupations may lead to latex sensitization, allergic asthma, and skin reactions. Due to their good properties and environmental safety NRL gloves are still being used in the healthcare setting, but also in the food industry, by hairdressers, cleaners, etc. The aim of our study was to assess the protein and NRL allergen content in commercial gloves by different methods, including a new assay. Twenty commercially available NRL gloves were analyzed. Protein extraction was performed according to the international standard ASTM D-5712. Total protein content was measured with a modified Lowry method, NRL content with the CAP Inhibition Assay, the Beezhold ELISA Inhibition Assay, and an innovative ELISA with IgY-antibodies extracted from eggs of NRL-immunized hens (IgY Inhibition Assay). We found a high protein content in a range of 215.0-1304.7 μg/g in 8 out of the 20 NRL gloves. Seven of the 20 gloves were powdered, four of them with a high protein content. In gloves with high protein content, the immunological tests detected congruently high levels of NRL allergen. We conclude that a high percentage of commercially available NRL gloves still represent a risk for NRL allergy, including asthma. The modified Lowry Method allows to infer on the latex allergen content.

Rapid Active Assay for the Detection of Antibodies to West Nile Virus in Chickens

National Research Council Canada - National Science Library

Groves, Stephanie S; Turell, Michael J; Bailey, Charles L; Morozov, Victor N

2008-01-01

... by detection of bound IgM molecules with functionalized magnetic beads as active labels. This assay takes only 15 minutes and has the same sensitivity as a commercially available human WNV IgM antibody-capture enzyme-linked immunosorbent assay...

Fluorescence lifetime assays: current advances and applications in drug discovery.

Science.gov (United States)

Pritz, Stephan; Doering, Klaus; Woelcke, Julian; Hassiepen, Ulrich

2011-06-01

Fluorescence lifetime assays complement the portfolio of established assay formats available in drug discovery, particularly with the recent advances in microplate readers and the commercial availability of novel fluorescent labels. Fluorescence lifetime assists in lowering complexity of compound screening assays, affording a modular, toolbox-like approach to assay development and yielding robust homogeneous assays. To date, materials and procedures have been reported for biochemical assays on proteases, as well as on protein kinases and phosphatases. This article gives an overview of two assay families, distinguished by the origin of the fluorescence signal modulation. The pharmaceutical industry demands techniques with a robust, integrated compound profiling process and short turnaround times. Fluorescence lifetime assays have already helped the drug discovery field, in this sense, by enhancing productivity during the hit-to-lead and lead optimization phases. Future work will focus on covering other biochemical molecular modifications by investigating the detailed photo-physical mechanisms underlying the fluorescence signal.

Validity of transcobalamin II-based radioassay for the determination of serum vitamin B12 concentrations

International Nuclear Information System (INIS)

Paltridge, G.; Rudzki, Z.; Ryall, R.G.

1980-01-01

A valid radioassay for the estimation of serum vitamin B 12 in the presence of naturally occurring vitamin B 12 (= cobalamin) analogues can be operated if serum transcobalamin II (TC II) is used as the binding protein. Serum samples that gave diagnostically discrepant results when their vitamin B 12 content was analysed (i) by a commercial radioassay known to be susceptible to interference from cobalamin analogues, and (ii) by microbiological assay, were further analysed by an alternative radioassay which uses the transcobalamins (principally TC II) of diluted normal serum as the assay binding protein. Concordance between the results from microbiological assay and the TC II-based radioassay was found in all cases. In an extended study over a three-year period, all routine serum samples sent for vitamin B 12 analysis that had a vitamin B 12 content of less than 320 ng/l by the TC II-based radioassay (reference range 200-850 ng/l) were reanalysed using an established microbiological method. Over 1000 samples were thus analysed. The data are presented to demonstrate the validity of the TC II-based radioassay results in this group of patients, serum samples from which are most likely to produce diagnostically erroneous vitamin B 12 results when analysed by a radioassay that is less specific for cobalamins. (author)

Validity of a Commercial Linear Encoder to Estimate Bench Press 1 RM from the Force-Velocity Relationship

Science.gov (United States)

Bosquet, Laurent; Porta-Benache, Jeremy; Blais, Jérôme

2010-01-01

The aim of this study was to assess the validity and accuracy of a commercial linear encoder (Musclelab, Ergotest, Norway) to estimate Bench press 1 repetition maximum (1RM) from the force - velocity relationship. Twenty seven physical education students and teachers (5 women and 22 men) with a heterogeneous history of strength training participated in this study. They performed a 1 RM test and a force - velocity test using a Bench press lifting task in a random order. Mean 1 RM was 61.8 ± 15.3 kg (range: 34 to 100 kg), while 1 RM estimated by the Musclelab’s software from the force-velocity relationship was 56.4 ± 14.0 kg (range: 33 to 91 kg). Actual and estimated 1 RM were very highly correlated (r = 0.93, p<0.001) but largely different (Bias: 5.4 ± 5.7 kg, p < 0.001, ES = 1.37). The 95% limits of agreement were ±11.2 kg, which represented ±18% of actual 1 RM. It was concluded that 1 RM estimated from the force-velocity relationship was a good measure for monitoring training induced adaptations, but also that it was not accurate enough to prescribe training intensities. Additional studies are required to determine whether accuracy is affected by age, sex or initial level. Key points Some commercial devices allow to estimate 1 RM from the force-velocity relationship. These estimations are valid. However, their accuracy is not high enough to be of practical help for training intensity prescription. Day-to-day reliability of force and velocity measured by the linear encoder has been shown to be very high, but the specific reliability of 1 RM estimated from the force-velocity relationship has to be determined before concluding to the usefulness of this approach in the monitoring of training induced adaptations. PMID:24149641

A novel clot lysis assay for recombinant plasminogen activator.

Science.gov (United States)

Jamialahmadi, Oveis; Fazeli, Ahmad; Hashemi-Najafabadi, Sameereh; Fazeli, Mohammad Reza

2015-03-01

Recombinant plasminogen activator (r-PA, reteplase) is an engineered variant of alteplase. When expressed in E. coli, it appears as inclusion bodies that require refolding to recover its biological activity. An important step following refolding is to determine the activity of refolded protein. Current methods for enzymatic activity of thrombolytic drugs are costly and complex. Here a straightforward and low-cost clot lysis assay was developed. It quantitatively measures the activity of the commercial reteplase and is also capable of screening refolding conditions. As evidence for adequate accuracy and sensitivity of the current assay, r-PA activity measurements are shown to be comparable to those obtained from chromogenic substrate assay.

Development and validation of a HPLC method for standardization of herbal and commercial extracts of Myrcia uniflora

Directory of Open Access Journals (Sweden)

Andrea N. de L. Batista

2011-06-01

Full Text Available Myrcia uniflora Barb. Rodr., Myrtaceae, popularly known as "pedra-hume-caá" in Brazil, is sold as dry extracts in capsules or as tinctures for the treatment of diabetes mellitus. Previous phytochemical studies on this species described the occurrence of the flavonoids mearnsitrin and myricitrin. In the present study, the chromatographic profiles of M. uniflora leaves and commercial extracts were determined using HPLC-PAD. Myricitrin was used as an external standard in the development and validation of the HPLC method. The proposed method is simple, rapid and reliable and can be successfully applied in industry for standardization of herbs and phytomedicines commercialised in Brazil as "pedra-hume-caá".

Development and validation of a HPLC method for standardization of herbal and commercial extracts of Myrcia uniflora

Directory of Open Access Journals (Sweden)

Andrea N. de L. Batista

2011-04-01

Full Text Available Myrcia uniflora Barb. Rodr., Myrtaceae, popularly known as "pedra-hume-caá" in Brazil, is sold as dry extracts in capsules or as tinctures for the treatment of diabetes mellitus. Previous phytochemical studies on this species described the occurrence of the flavonoids mearnsitrin and myricitrin. In the present study, the chromatographic profiles of M. uniflora leaves and commercial extracts were determined using HPLC-PAD. Myricitrin was used as an external standard in the development and validation of the HPLC method. The proposed method is simple, rapid and reliable and can be successfully applied in industry for standardization of herbs and phytomedicines commercialised in Brazil as "pedra-hume-caá".

Cell Culture Assay for Human Noroviruses [response

Energy Technology Data Exchange (ETDEWEB)

Straub, Tim M.; Honer Zu Bentrup, Kerstin; Orosz Coghlan, Patricia; Dohnalkova, Alice; Mayer, Brooke K.; Bartholomew, Rachel A.; Valdez, Catherine O.; Bruckner-Lea, Cindy J.; Gerba, Charles P.; Abbaszadegan, Morteza A.; Nickerson, Cheryl A.

2007-07-01

We appreciate the comments provided by Leung et al., in response to our recently published article “In Vitro Cell Culture Infectivity Assay for Human Noroviruses” by Straub et al. (1). The specific aim of our project was to develop an in vitro cell culture infectivity assay for human noroviruses (hNoV) to enhance risk assessments when they are detected in water supplies. Reverse transcription (RT) qualitative or quantitative PCR are the primary assays for waterborne NoV monitoring. However, these assays cannot distinguish between infectious vs. non-infectious virions. When hNoV is detected in water supplies, information provided by our infectivity assay will significantly improve risk assessment models and protect human health, regardless of whether we are propagating NoV. Indeed, in vitro cell culture infectivity assays for the waterborne pathogen Cryptosporidium parvum that supplement approved fluorescent microscopy assays, do not result in amplification of the environmentally resistant hard-walled oocysts (2). However, identification of life cycle stages in cell culture provides evidence of infectious oocysts in a water supply. Nonetheless, Leung et al.’s assertion regarding the suitability of our method for the in vitro propagation of high titers of NoV is valid for the medical research community. In this case, well-characterized challenge pools of virus would be useful for developing and testing diagnostics, therapeutics, and vaccines. As further validation of our published findings, we have now optimized RT quantitative PCR to assess the level of viral production in cell culture, where we are indeed finding significant increases in viral titer. The magnitude and time course of these increases is dependent on both virus strain and multiplicity of infection. We are currently preparing a manuscript that will discuss these findings in greater detail, and the implications this may have for creating viral challenge pools

Quantitative Validation of the Presto Blue Metabolic Assay for Online Monitoring of Cell Proliferation in a 3D Perfusion Bioreactor System.

Science.gov (United States)

Sonnaert, Maarten; Papantoniou, Ioannis; Luyten, Frank P; Schrooten, Jan Ir

2015-06-01

As the fields of tissue engineering and regenerative medicine mature toward clinical applications, the need for online monitoring both for quantitative and qualitative use becomes essential. Resazurin-based metabolic assays are frequently applied for determining cytotoxicity and have shown great potential for monitoring 3D bioreactor-facilitated cell culture. However, no quantitative correlation between the metabolic conversion rate of resazurin and cell number has been defined yet. In this work, we determined conversion rates of Presto Blue, a resazurin-based metabolic assay, for human periosteal cells during 2D and 3D static and 3D perfusion cultures. Our results showed that for the evaluated culture systems there is a quantitative correlation between the Presto Blue conversion rate and the cell number during the expansion phase with no influence of the perfusion-related parameters, that is, flow rate and shear stress. The correlation between the cell number and Presto Blue conversion subsequently enabled the definition of operating windows for optimal signal readouts. In conclusion, our data showed that the conversion of the resazurin-based Presto Blue metabolic assay can be used as a quantitative readout for online monitoring of cell proliferation in a 3D perfusion bioreactor system, although a system-specific validation is required.

Quantitative Validation of the Presto Blue™ Metabolic Assay for Online Monitoring of Cell Proliferation in a 3D Perfusion Bioreactor System

Science.gov (United States)

Sonnaert, Maarten; Papantoniou, Ioannis; Luyten, Frank P.

2015-01-01

As the fields of tissue engineering and regenerative medicine mature toward clinical applications, the need for online monitoring both for quantitative and qualitative use becomes essential. Resazurin-based metabolic assays are frequently applied for determining cytotoxicity and have shown great potential for monitoring 3D bioreactor-facilitated cell culture. However, no quantitative correlation between the metabolic conversion rate of resazurin and cell number has been defined yet. In this work, we determined conversion rates of Presto Blue™, a resazurin-based metabolic assay, for human periosteal cells during 2D and 3D static and 3D perfusion cultures. Our results showed that for the evaluated culture systems there is a quantitative correlation between the Presto Blue conversion rate and the cell number during the expansion phase with no influence of the perfusion-related parameters, that is, flow rate and shear stress. The correlation between the cell number and Presto Blue conversion subsequently enabled the definition of operating windows for optimal signal readouts. In conclusion, our data showed that the conversion of the resazurin-based Presto Blue metabolic assay can be used as a quantitative readout for online monitoring of cell proliferation in a 3D perfusion bioreactor system, although a system-specific validation is required. PMID:25336207

Development of a TaqMan assay for the six major genotypes of hepatitis C virus: Comparison with commercial assays

DEFF Research Database (Denmark)

Engle, Ronald E; Russell, Rodney S; Purcell, Robert H

2008-01-01

A quantitative real-time PCR assay was developed that detects genomic RNA from reference strains representing the six major genotypes of hepatitis C virus (HCV) with equal sensitivity and accurately measured HCV RNA in JFH1 HCV-infected Huh7.5 cells. The method is indirectly calibrated to the first...

Validation of a modified fluorimetric assay for the screening of trichomonacidal drugs

Directory of Open Access Journals (Sweden)

Alexandra Ibáñez Escribano

2012-08-01

Full Text Available A fluorimetric microassay that uses a redox dye to determine the viability of the flagellate Trichomonas vaginalis has been optimised to provide a more sensitive method to evaluate potential trichomonacidal compounds. Resazurin has been used in recent years to test drugs against different parasites, including trichomonadid protozoa; however, the reproducibility of these resazurin-based methods in our laboratory has been limited because the flagellate culture medium spontaneously reduces the resazurin. The objective of this work was to refine the fluorimetric microassay method previously developed by other research groups to reduce the fluorescence background generated by the media and increase the sensitivity of the screening assay. The experimental conditions, time of incubation, resazurin concentration and media used in the microtitre plates were adjusted. Different drug sensitivity studies against T. vaginalis were developed using the 5-nitroimidazole reference drugs, new 5-nitroindazolinones and 5-nitroindazole synthetic derivatives. Haemocytometer count results were compared with the resazurin assay using a 10% solution of 3 mM resazurin dissolved in phosphate buffered saline with glucose (1 mg/mL. The fluorimetric assay and the haemocytometer counts resulted in similar percentages of trichomonacidal activity in all the experiments, demonstrating that the fluorimetric microtitre assay has the necessary accuracy for high-throughput screening of new drugs against T. vaginalis.

A fluorescence sedimentation assay for dsDNA antibodies

DEFF Research Database (Denmark)

Duus, K; Draborg, A H; Güven, E

2017-01-01

The Farr assay is a radioimmunoassay (RIA) for dsDNA antibodies, based on antibody precipitation using ammonium sulphate and quantification using radio-labelled dsDNA. The RIA-Farr assay offers outstanding clinical specificity and sensitivity for systemic lupus erythematosus (SLE) compared to other...... on precipitation with polyethylene glycol (PEG) and fluorescence of EvaGreen intercalated in dsDNA as detection principle. As dsDNA antibodies are quantified using fluorescence, the disadvantages of working with radioactivity are eliminated. The Fluoro-Farr assay was developed and validated, and the diagnostic...

Validation of a single nucleotide polymorphism (SNP) typing assay with 49 SNPs for forensic genetic testing in a laboratory accredited according to the ISO 17025 standard

DEFF Research Database (Denmark)

Børsting, Claus; Rockenbauer, Eszter; Morling, Niels

2009-01-01

cases and 33 twin cases were typed at least twice for the 49 SNPs. All electropherograms were analysed independently by two expert analysts prior to approval. Based on these results, detailed guidelines for analysis of the SBE products were developed. With these guidelines, the peak height ratio...... of a heterozygous allele call or the signal to noise ratio of a homozygous allele call is compared with previously obtained ratios. A laboratory protocol for analysis of SBE products was developed where allele calls with unusual ratios were highlighted to facilitate the analysis of difficult allele calls......A multiplex assay with 49 autosomal single nucleotide polymorphisms (SNPs) developed for human identification was validated for forensic genetic casework and accredited according to the ISO 17025 standard. The multiplex assay was based on the SNPforID 52plex SNP assay [J.J. Sanchez, C. Phillips, C...

Performance standard-based validation study for local lymph node assay: 5-bromo-2-deoxyuridine-flow cytometry method.

Science.gov (United States)

Ahn, Ilyoung; Kim, Tae-Sung; Jung, Eun-Sun; Yi, Jung-Sun; Jang, Won-Hee; Jung, Kyoung-Mi; Park, Miyoung; Jung, Mi-Sook; Jeon, Eun-Young; Yeo, Kyeong-Uk; Jo, Ji-Hoon; Park, Jung-Eun; Kim, Chang-Yul; Park, Yeong-Chul; Seong, Won-Keun; Lee, Ai-Young; Chun, Young Jin; Jeong, Tae Cheon; Jeung, Eui Bae; Lim, Kyung-Min; Bae, SeungJin; Sohn, Soojung; Heo, Yong

2016-10-01

Local lymph node assay: 5-bromo-2-deoxyuridine-flow cytometry method (LLNA: BrdU-FCM) is a modified non-radioisotopic technique with the additional advantages of accommodating multiple endpoints with the introduction of FCM, and refinement and reduction of animal use by using a sophisticated prescreening scheme. Reliability and accuracy of the LLNA: BrdU-FCM was determined according to OECD Test Guideline (TG) No. 429 (Skin Sensitization: Local Lymph Node Assay) performance standards (PS), with the participation of four laboratories. Transferability was demonstrated through successfully producing stimulation index (SI) values for 25% hexyl cinnamic aldehyde (HCA) consistently greater than 3, a predetermined threshold, by all participating laboratories. Within- and between-laboratory reproducibility was shown using HCA and 2,4-dinitrochlorobenzene, in which EC2.7 values (the estimated concentrations eliciting an SI of 2.7, the threshold for LLNA: BrdU-FCM) fell consistently within the acceptance ranges, 0.025-0.1% and 5-20%, respectively. Predictive capacity was tested using the final protocol version 1.3 for the 18 reference chemicals listed in OECD TG 429, of which results showed 84.6% sensitivity, 100% specificity, and 88.9% accuracy compared with the original LLNA. The data presented are considered to meet the performance criteria for the PS, and its predictive capacity was also sufficiently validated. Copyright © 2016 Elsevier Inc. All rights reserved.

Statistical inference for the within-device precision of quantitative measurements in assay validation.

Science.gov (United States)

Liu, Jen-Pei; Lu, Li-Tien; Liao, C T

2009-09-01

Intermediate precision is one of the most important characteristics for evaluation of precision in assay validation. The current methods for evaluation of within-device precision recommended by the Clinical Laboratory Standard Institute (CLSI) guideline EP5-A2 are based on the point estimator. On the other hand, in addition to point estimators, confidence intervals can provide a range for the within-device precision with a probability statement. Therefore, we suggest a confidence interval approach for assessment of the within-device precision. Furthermore, under the two-stage nested random-effects model recommended by the approved CLSI guideline EP5-A2, in addition to the current Satterthwaite's approximation and the modified large sample (MLS) methods, we apply the technique of generalized pivotal quantities (GPQ) to derive the confidence interval for the within-device precision. The data from the approved CLSI guideline EP5-A2 illustrate the applications of the confidence interval approach and comparison of results between the three methods. Results of a simulation study on the coverage probability and expected length of the three methods are reported. The proposed method of the GPQ-based confidence intervals is also extended to consider the between-laboratories variation for precision assessment.

Study on quantification of HBs-antibody by immunoradiometric assay

International Nuclear Information System (INIS)

Kondo, Yuichi; Itoi, Yoshihiro; Kajiyama, Shizuo

1989-01-01

Quantification of HBs-antibody assay was carried out using a commercialized assay kit and standard solutions of HBs-antibody recognised as 1 st reference preparation of hepatitis B immunogloblin by WHO. Standard curve of HBs-antibody was drawn with the function of 3D-spline and the correlation factor was obtained as r = 0.999. Coefficient of intra-assay variance was 3.8 % and that of inter-assay variance was 7.8 %. Dilution tests showed satisfactory results in the range of 2-16 times. Correlation between value of cut-off indices and concentration of HBs-antibody was obtained as the formula of y = 2.599 x-3.894 (r = 0.992) and 2.1 of cut-off index corresponded to about 5 mIU/ml of HBs-antibody concentration. (author)

Evaluation and validation of a single-dilution potency assay based upon serology of vaccines containing diphtheria toxoid: analysis for consistency in production and testing at the laboratory of the Control of Biological Products of the RIVM

NARCIS (Netherlands)

Akkermans AM; Hendriksen CFM; Marsman FR; de Jong WH; van de Donk HJM

1993-01-01

A single-dilution assay can be a valid procedure to demonstrate that a product exceeds the minimal requirement given for potency provided that consistency in production and testing has been proven. Information is presented justifying the use of a single dilution assay based upon quantitative

The validation and clinical implementation of BRCAplus: a comprehensive high-risk breast cancer diagnostic assay.

Directory of Open Access Journals (Sweden)

Hansook Kim Chong

Full Text Available Breast cancer is the most commonly diagnosed cancer in women, with 10% of disease attributed to hereditary factors. Although BRCA1 and BRCA2 account for a high percentage of hereditary cases, there are more than 25 susceptibility genes that differentially impact the risk for breast cancer. Traditionally, germline testing for breast cancer was performed by Sanger dideoxy terminator sequencing in a reflexive manner, beginning with BRCA1 and BRCA2. The introduction of next-generation sequencing (NGS has enabled the simultaneous testing of all genes implicated in breast cancer resulting in diagnostic labs offering large, comprehensive gene panels. However, some physicians prefer to only test for those genes in which established surveillance and treatment protocol exists. The NGS based BRCAplus test utilizes a custom tiled PCR based target enrichment design and bioinformatics pipeline coupled with array comparative genomic hybridization (aCGH to identify mutations in the six high-risk genes: BRCA1, BRCA2, PTEN, TP53, CDH1, and STK11. Validation of the assay with 250 previously characterized samples resulted in 100% detection of 3,025 known variants and analytical specificity of 99.99%. Analysis of the clinical performance of the first 3,000 BRCAplus samples referred for testing revealed an average coverage greater than 9,000X per target base pair resulting in excellent specificity and the sensitivity to detect low level mosaicism and allele-drop out. The unique design of the assay enabled the detection of pathogenic mutations missed by previous testing. With the abundance of NGS diagnostic tests being released, it is essential that clinicians understand the advantages and limitations of different test designs.

Infection among Commercial Sex Workers in Jos

African Journals Online (AJOL)

A study of HHV8 seropositivity was conducted among commercial sex workers in Jos aimed at determining the prevalence in relation to history of STD, duration of prostitution, age and number of sexual partners per day. Antibodies to HHV8 were detected by enzyme linked - immunosorbent assay (ELISA) (Advanced ...

Field validation of food service listings: a comparison of commercial and online geographic information system databases.

Science.gov (United States)

Seliske, Laura; Pickett, William; Bates, Rebecca; Janssen, Ian

2012-08-01

Many studies examining the food retail environment rely on geographic information system (GIS) databases for location information. The purpose of this study was to validate information provided by two GIS databases, comparing the positional accuracy of food service places within a 1 km circular buffer surrounding 34 schools in Ontario, Canada. A commercial database (InfoCanada) and an online database (Yellow Pages) provided the addresses of food service places. Actual locations were measured using a global positioning system (GPS) device. The InfoCanada and Yellow Pages GIS databases provided the locations for 973 and 675 food service places, respectively. Overall, 749 (77.1%) and 595 (88.2%) of these were located in the field. The online database had a higher proportion of food service places found in the field. The GIS locations of 25% of the food service places were located within approximately 15 m of their actual location, 50% were within 25 m, and 75% were within 50 m. This validation study provided a detailed assessment of errors in the measurement of the location of food service places in the two databases. The location information was more accurate for the online database, however, when matching criteria were more conservative, there were no observed differences in error between the databases.

Biomarker discovery for colon cancer using a 761 gene RT-PCR assay

Directory of Open Access Journals (Sweden)

Hackett James R

2007-08-01

Full Text Available Abstract Background Reverse transcription PCR (RT-PCR is widely recognized to be the gold standard method for quantifying gene expression. Studies using RT-PCR technology as a discovery tool have historically been limited to relatively small gene sets compared to other gene expression platforms such as microarrays. We have recently shown that TaqMan® RT-PCR can be scaled up to profile expression for 192 genes in fixed paraffin-embedded (FPE clinical study tumor specimens. This technology has also been used to develop and commercialize a widely used clinical test for breast cancer prognosis and prediction, the Onco typeDX™ assay. A similar need exists in colon cancer for a test that provides information on the likelihood of disease recurrence in colon cancer (prognosis and the likelihood of tumor response to standard chemotherapy regimens (prediction. We have now scaled our RT-PCR assay to efficiently screen 761 biomarkers across hundreds of patient samples and applied this process to biomarker discovery in colon cancer. This screening strategy remains attractive due to the inherent advantages of maintaining platform consistency from discovery through clinical application. Results RNA was extracted from formalin fixed paraffin embedded (FPE tissue, as old as 28 years, from 354 patients enrolled in NSABP C-01 and C-02 colon cancer studies. Multiplexed reverse transcription reactions were performed using a gene specific primer pool containing 761 unique primers. PCR was performed as independent TaqMan® reactions for each candidate gene. Hierarchal clustering demonstrates that genes expected to co-express form obvious, distinct and in certain cases very tightly correlated clusters, validating the reliability of this technical approach to biomarker discovery. Conclusion We have developed a high throughput, quantitatively precise multi-analyte gene expression platform for biomarker discovery that approaches low density DNA arrays in numbers of

Integrated bioassays in microfluidic devices: botulinum toxin assays.

Science.gov (United States)

Mangru, Shakuntala; Bentz, Bryan L; Davis, Timothy J; Desai, Nitin; Stabile, Paul J; Schmidt, James J; Millard, Charles B; Bavari, Sina; Kodukula, Krishna

2005-12-01

A microfluidic assay was developed for screening botulinum neurotoxin serotype A (BoNT-A) by using a fluorescent resonance energy transfer (FRET) assay. Molded silicone microdevices with integral valves, pumps, and reagent reservoirs were designed and fabricated. Electrical and pneumatic control hardware were constructed, and software was written to automate the assay protocol and data acquisition. Detection was accomplished by fluorescence microscopy. The system was validated with a peptide inhibitor, running 2 parallel assays, as a feasibility demonstration. The small footprint of each bioreactor cell (0.5 cm2) and scalable fluidic architecture enabled many parallel assays on a single chip. The chip is programmable to run a dilution series in each lane, generating concentration-response data for multiple inhibitors. The assay results showed good agreement with the corresponding experiments done at a macroscale level. Although the system has been developed for BoNT-A screening, a wide variety of assays can be performed on the microfluidic chip with little or no modification.

The impact of pre-analytical variables on the stability of neurofilament proteins in CSF, determined by a novel validated SinglePlex Luminex assay and ELISA.

Science.gov (United States)

Koel-Simmelink, Marleen J A; Vennegoor, Anke; Killestein, Joep; Blankenstein, Marinus A; Norgren, Niklas; Korth, Carsten; Teunissen, Charlotte E

2014-01-15

Neurofilament (Nf) proteins have been shown to be promising biomarkers for monitoring and predicting disease progression for various neurological diseases. The aim of this study was to evaluate the effects of pre-analytical variables on the concentration of neurofilament heavy (NfH) and neurofilament light (NfL) proteins. For NfH an in-house newly-developed and validated SinglePlex Luminex assay was used; ELISA was used to analyze NfL. For the NfL ELISA assay, the intra- and inter-assay variation was respectively, 1.5% and 16.7%. Analytical performance of the NfH SinglePlex Luminex assay in terms of sensitivity (6.6pg/mL), recovery in cerebrospinal fluid (CSF) (between 90 and 104%), linearity (from 6.6-1250pg/mL), and inter- and intra-assay variation (<8%) were good. Concentrations of both NfL and NfH appeared not negatively affected by blood contamination, repeated freeze-thaw cycles (up to 4), delayed processing (up to 24hours) and during long-term storage at -20°C, 4°C, and room temperature. A decrease in concentration was observed during storage of both neurofilament proteins up to 21days at 37°C, which was significant by day 5. The newly developed NfH SinglePlex Luminex assay has a good sensitivity and is robust. Moreover, both NfH and NfL are stable under the most prevalent pre-analytical variations. Copyright © 2013 Elsevier B.V. All rights reserved.

Analytical and clinical performance of the new Fujirebio 25-OH vitamin D assay, a comparison with liquid chromatography-tandem mass spectrometry (LC-MS/MS) and three other automated assays

OpenAIRE

Saleh, Lanja; Mueller, Daniel; von Eckardstein, Arnold

2015-01-01

BACKGROUND: We evaluated the analytical and clinical performance of the new Lumipulse® G 25-OH vitamin D assay from Fujirebio, and compared it to a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method and three other commercial automated assays. METHODS: Total 25 hydroxy vitamin D (25(OH)D) levels were measured in 100 selected serum samples from our routine analysis with Fujirebio 25(OH)D assay. The results were compared with those obtained with LC-MS/MS and three other automat...

A murine monoclonal antibody based enzyme-linked immunosorbent assay for almond (Prunus dulcis L.) detection.

Science.gov (United States)

Su, Mengna; Venkatachalam, Mahesh; Liu, Changqi; Zhang, Ying; Roux, Kenneth H; Sathe, Shridhar K

2013-11-13

A sandwich enzyme-linked immunosorbent assay (ELISA) using anti-almond soluble protein rabbit polyclonal antibodies as capture antibodies and murine monoclonal antibody 4C10 as the detection antibodies was developed. The assay is specific and sensitive (3-200 ng almond protein/mL) for almond detection. The standardized assay is accurate (assay variability assay did not register any cross-reactivity with the tested food matrices, suggesting the assay to be almond amandin specific. The assay could detect the presence of declared almond in the tested matched commercial samples. Further, the assay reliably detected the presence of almonds in the laboratory prepared food samples spiked with almond flour.

Radioimmunoassay kit formulation and its validation for serum progesterone using progesterone radiotracer purified by gel filtration

International Nuclear Information System (INIS)

Karir, T.; Pal, N.; Sivaprasad, N.

2003-01-01

Purification of the radioiodinated progesterone tyrosine methyl ester conjugate by gel filtration and the development, optimization and clinical validation of a direct radioimmunoassay (RIA) of progesterone using this radiotracer are described. High purity radiotracer is essential for the error free performance of any RIA. Progesterone 11α hemisuccinate was conjugated to tyrosine methyl ester (TME) by the mixed anhydride method and this conjugate was then radioiodinated by the chloramine-T method. Purification of the radioiodinated product was carried out by gel filtration. About 12 batches of the radiotracer were prepared and purified. The purification by gel filtration gave reproducible elution pattern and purity. The radiotracer thus purified was found to have consistent quality as compared to that of any other purification methods. Non-specific binding of the radiotracer was found to be 95% as checked by paper electrophoresis. The stability (retention of the immunoreactivity) of the radiotracer was two to three months. No appreciable changes in the assay characteristics were observed during this period. The assay involved 3 hours incubation of progesterone antibody with individual standards or sample and radiotracer at room temperature. The optimized assay was then validated for internal and external quality control parameters. A RIA kit was then formulated with this radiotracer for estimation of progesterone in serum. The assay kit consisted of lyophilized individual standards ranging from 0.25 to 50 ng/ml. The clinical performance of the developed kit was compared with that of a commercial ELISA kit and a correlation of 0.94 was observed. (author)

Serotype determination of Salmonella by xTAG assay.

Science.gov (United States)

Zheng, Zhibei; Zheng, Wei; Wang, Haoqiu; Pan, Jincao; Pu, Xiaoying

2017-10-01

Currently, no protocols or commercial kits are available to determine the serotypes of Salmonella by using Luminex MAGPIX®. In this study, an xTAG assay for serotype determination of Salmonella suitable for Luminex MAGPIX® is described and 228 Salmonella isolates were serotype determined by this xTAG assay. The xTAG assay consists of two steps: 1) Multiplex PCR to amplify simultaneously O, H and Vi antigen genes of Salmonella, and 2) Magplex-TAG™ microsphere hybridization to identify accurately the specific PCR products of different antigens. Compared with the serotyping results of traditional serum agglutination test, the sensitivity and specificity of the xTAG assay were 95.1% and 100%, respectively. The agreement rate of these two assays was 95.2%. Compared with Luminex xMAP® Salmonella Serotyping Assay (SSA) kit, the advantages of this xTAG assay are: First, the magnetic beads make it applicable to both the Luminex®100/200™ and MAGPIX® systems. Second, only primers rather than both primers and probes are needed in the xTAG assay, and the process of coupling antigen-specific oligonucleotide probes to beads is circumvented, which make the xTAG assay convenient to be utilized by other laboratories. The xTAG assay may serve as a rapid alternative or complementary method for traditional Salmonella serotyping tests, especially for laboratories that utilize the MAGPIX® systems. Copyright © 2017 Elsevier B.V. All rights reserved.

OpenComet: An automated tool for comet assay image analysis

OpenAIRE

Gyori, Benjamin M.; Venkatachalam, Gireedhar; Thiagarajan, P.S.; Hsu, David; Clement, Marie-Veronique

2014-01-01

Reactive species such as free radicals are constantly generated in vivo and DNA is the most important target of oxidative stress. Oxidative DNA damage is used as a predictive biomarker to monitor the risk of development of many diseases. The comet assay is widely used for measuring oxidative DNA damage at a single cell level. The analysis of comet assay output images, however, poses considerable challenges. Commercial software is costly and restrictive, while free software generally requires ...

Martian Superoxide and Peroxide O2 Release (OR) Assay: A New Technology for Terrestrial and Planetary Applications

Science.gov (United States)

Georgiou, Christos D.; Zisimopoulos, Dimitrios; Panagiotidis, Konstantinos; Grintzalis, Kontantinos; Papapostolou, Ioannis; Quinn, Richard C.; McKay, Christopher P.; Sun, Henry J.

2015-01-01

This study presents an assay for the detection and quantification of soil metal superoxides and peroxides in regolith and soil. The O2 release (OR) assay is based on the enzymatic conversion of the hydrolysis products of metal oxides to O2, and their quantification by an O2 electrode based on the stoichiometry of the involved reactions: The intermediate product O2 from the hydrolysis of metal superoxides is converted by cytochrome c to O2, and also by superoxide dismutase (SOD) to 1/2 mol O2 and 1/2 mol H2O2, which is then converted by catalase (CAT) to 1/2 mol O2. The product H2O2 from the hydrolysis of metal peroxides and hydroperoxides is converted to 1/2 mol O2 by CAT. The assay-method was validated in a sealed sample chamber using a liquid-phase Clark-type O2 electrode with known concentrations of O2 and H2O2, and with commercial metal superoxide and peroxide mixed with Mars analogue Mojave and Atacama Desert soils. Carbonates and perchlorates, both present on Mars, do not interfere with the assay. The assay lower limit of detection, using luminescence quenching/optical sensing O2-electrodes, is 1 nmol O2 cm(exp. -3) or better. The activity of the assay enzymes SOD and cytochrome c was unaffected up to 6 Gy exposure by gamma-radiation, while CAT retained 100% and 40% of its activity at 3 and 6 Gy, respectively, demonstrating the suitability of these enzymes for planetary missions, e.g., in Mars or Europa.

Modular enrichment measurement system for in-situ enrichment assay

International Nuclear Information System (INIS)

Stewart, J.P.

1976-01-01

A modular enrichment measurement system has been designed and is in operation within General Electric's Nuclear Fuel Fabrication Facility for the in-situ enrichment assay of uranium-bearing materials in process containers. This enrichment assay system, which is based on the ''enrichment meter'' concept, is an integral part of the site's enrichment control program and is used in the in-situ assay of the enrichment of uranium dioxide (UO 2 ) powder in process containers (five gallon pails). The assay system utilizes a commercially available modular counting system and a collimnator designed for compatability with process container transport lines and ease of operator access. The system has been upgraded to include a microprocessor-based controller to perform system operation functions and to provide data acquisition and processing functions. Standards have been fabricated and qualified for the enrichment assay of several types of uranium-bearing materials, including UO 2 powders. The assay system has performed in excess of 20,000 enrichment verification measurements annually and has significantly contributed to the facility's enrichment control program

CLSI-based transference of the CALIPER database of pediatric reference intervals from Abbott to Beckman, Ortho, Roche and Siemens Clinical Chemistry Assays: direct validation using reference samples from the CALIPER cohort.

Science.gov (United States)

Estey, Mathew P; Cohen, Ashley H; Colantonio, David A; Chan, Man Khun; Marvasti, Tina Binesh; Randell, Edward; Delvin, Edgard; Cousineau, Jocelyne; Grey, Vijaylaxmi; Greenway, Donald; Meng, Qing H; Jung, Benjamin; Bhuiyan, Jalaluddin; Seccombe, David; Adeli, Khosrow

2013-09-01

The CALIPER program recently established a comprehensive database of age- and sex-stratified pediatric reference intervals for 40 biochemical markers. However, this database was only directly applicable for Abbott ARCHITECT assays. We therefore sought to expand the scope of this database to biochemical assays from other major manufacturers, allowing for a much wider application of the CALIPER database. Based on CLSI C28-A3 and EP9-A2 guidelines, CALIPER reference intervals were transferred (using specific statistical criteria) to assays performed on four other commonly used clinical chemistry platforms including Beckman Coulter DxC800, Ortho Vitros 5600, Roche Cobas 6000, and Siemens Vista 1500. The resulting reference intervals were subjected to a thorough validation using 100 reference specimens (healthy community children and adolescents) from the CALIPER bio-bank, and all testing centers participated in an external quality assessment (EQA) evaluation. In general, the transferred pediatric reference intervals were similar to those established in our previous study. However, assay-specific differences in reference limits were observed for many analytes, and in some instances were considerable. The results of the EQA evaluation generally mimicked the similarities and differences in reference limits among the five manufacturers' assays. In addition, the majority of transferred reference intervals were validated through the analysis of CALIPER reference samples. This study greatly extends the utility of the CALIPER reference interval database which is now directly applicable for assays performed on five major analytical platforms in clinical use, and should permit the worldwide application of CALIPER pediatric reference intervals. Copyright © 2013 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Validation of a Non-Specific Dye Real-Time PCR Assay for Porcine Adulteration in Meatball Using ND5 Primer

Directory of Open Access Journals (Sweden)

Tri Joko Raharjo

2017-07-01

Full Text Available Porcine adulteration in meatball samples were analyzed using real-time polymerase chain reaction (RT-PCR, based on the ND5 primer obtained by previous study. This work consisted of three stages which were annealing temperature optimization, method validation, and application. DNA template was extracted using phenol-CIAA (chloroform-iso amyl alcohol method. The optimum annealing temperature for ND5 primers (forward primer 5'-CATTCGCCTCACTCACATTAACC-3' and reverse primer 5'-AAGAGAGAGTTCTACGGTCTGTAG-3' was 58.0 °C, obtained after testing annealing at 50.5 to 59.5 °C gradient temperature with 5 °C interval. Melting curve analysis was done at 65.0 to 95.0 °C, with increasing temperature for 0.5 °C per 2 sec. Method was validated for its specificity, precision and limit of detection. RT-PCR method with ND5 primers produced 227 bp DNA fragment with 78.50 °C Tm value. From eight commercial meatball samples, one was detected containing porcine. The methods showed high specificity and precision, with experimentally determined limits for porcine were no less than 1%.

Evaluation of the Thermo Scientific SureTect Listeria species assay. AOAC Performance Tested Method 071304.

Science.gov (United States)

Cloke, Jonathan; Evans, Katharine; Crabtree, David; Hughes, Annette; Simpson, Helen; Holopainen, Jani; Wickstrand, Nina; Kauppinen, Mikko; Leon-Velarde, Carlos; Larson, Nathan; Dave, Keron

2014-01-01

The Thermo Scientific SureTect Listeria species Assay is a new real-time PCR assay for the detection of all species of Listeria in food and environmental samples. This validation study was conducted using the AOAC Research Institute (RI) Performance Tested Methods program to validate the SureTect Listeria species Assay in comparison to the reference method detailed in International Organization for Standardization 11290-1:1996 including amendment 1:2004 in a variety of foods plus plastic and stainless steel. The food matrixes validated were smoked salmon, processed cheese, fresh bagged spinach, cantaloupe, cooked prawns, cooked sliced turkey meat, cooked sliced ham, salami, pork frankfurters, and raw ground beef. All matrixes were tested by Thermo Fisher Scientific, Microbiology Division, Basingstoke, UK. In addition, three matrixes (pork frankfurters, fresh bagged spinach, and stainless steel surface samples) were analyzed independently as part of the AOAC-RI-controlled independent laboratory study by the University ofGuelph, Canada. Using probability of detection statistical analysis, a significant difference in favour of the SureTect assay was demonstrated between the SureTect and reference method for high level spiked samples of pork frankfurters, smoked salmon, cooked prawns, stainless steel, and low-spiked samples of salami. For all other matrixes, no significant difference was seen between the two methods during the study. Inclusivity testing was conducted with 68 different isolates of Listeria species, all of which were detected by the SureTect Listeria species Assay. None of the 33 exclusivity isolates were detected by the SureTect Listeria species Assay. Ruggedness testing was conducted to evaluate the performance of the assay with specific method deviations outside of the recommended parameters open to variation, which demonstrated that the assay gave reliable performance. Accelerated stability testing was additionally conducted, validating the assay

Herpes Murine Model as a Biological Assay to Test Dialyzable Leukocyte Extracts Activity

Directory of Open Access Journals (Sweden)

Nohemí Salinas-Jazmín

2015-01-01

Full Text Available Human dialyzable leukocyte extracts (DLEs are heterogeneous mixtures of low-molecular-weight peptides that are released on disruption of peripheral blood leukocytes from healthy donors. DLEs improve clinical responses in infections, allergies, cancer, and immunodeficiencies. Transferon is a human DLE that has been registered as a hemoderivate by Mexican health authorities and commercialized nationally. To develop an animal model that could be used routinely as a quality control assay for Transferon, we standardized and validated a murine model of cutaneous HSV-1 infection. Using this model, we evaluated the activity of 27 Transferon batches. All batches improved the survival of HSV-1-infected mice, wherein average survival rose from 20.9% in control mice to 59.6% in Transferon-treated mice. The activity of Transferon correlated with increased serum levels of IFN-γ and reduced IL-6 and TNF-α concentrations. Our results demonstrate that (i this mouse model of cutaneous herpes can be used to examine the activity of DLEs, such as Transferon; (ii the assay can be used as a routine test for batch release; (iii Transferon is produced with high homogeneity between batches; (iv Transferon does not have direct virucidal, cytoprotective, or antireplicative effects; and (v the protective effect of Transferon in vivo correlates with changes in serum cytokines.

A universal and reliable assay for molecular sex identification of three-spined sticklebacks (Gasterosteus aculeatus).

Science.gov (United States)

Toli, E-A; Calboli, F C F; Shikano, T; Merilä, J

2016-11-01

In heterogametic species, biological differences between the two sexes are ubiquitous, and hence, errors in sex identification can be a significant source of noise and bias in studies where sex-related sources of variation are of interest or need to be controlled for. We developed and validated a universal multimarker assay for reliable sex identification of three-spined sticklebacks (Gasterosteus aculeatus). The assay makes use of genotype scores from three sex-linked loci and utilizes Bayesian probabilistic inference to identify sex of the genotyped individuals. The results, validated with 286 phenotypically sexed individuals from six populations of sticklebacks representing all major genetic lineages (cf. Pacific, Atlantic and Japan Sea), indicate that in contrast to commonly used single-marker-based sex identification assays, the developed multimarker assay should be 100% accurate. As the markers in the assay can be scored from agarose gels, it provides a quick and cost-efficient tool for universal sex identification of three-spined sticklebacks. The general principle of combining information from multiple markers to improve the reliability of sex identification is transferable and can be utilized to develop and validate similar assays for other species. © 2016 John Wiley & Sons Ltd.

Recombinant Helicobacter bilis Protein P167 for Mouse Serodiagnosis in a Multiplex Microbead Assay

OpenAIRE

Feng, Sunlian; Kendall, Lon V.; Hodzic, Emir; Wong, Scott; Lorenzana, Edward; Freet, Kimberly; Ku, Karin S.; Luciw, Paul A.; Barthold, Stephen W.; Khan, Imran H.

2004-01-01

Infection of mice with Helicobacter bilis is widespread in research and commercial mouse colonies. Therefore, sensitive, specific, and high-throughput assays are needed for rapid and accurate testing of mice in large numbers. This report describes a novel multiplex assay, based on fluorescent microbeads, for serodetection of H. bilis infection. The assay requires only a few microliters of serum to perform and is amenable to a high-throughput format. Individual microbead sets were conjugated t...

Validation of a second-generation multivariate index assay for malignancy risk of adnexal masses.

Science.gov (United States)

Coleman, Robert L; Herzog, Thomas J; Chan, Daniel W; Munroe, Donald G; Pappas, Todd C; Smith, Alan; Zhang, Zhen; Wolf, Judith

2016-07-01

Women with adnexal mass suspected of ovarian malignancy are likely to benefit from consultation with a gynecologic oncologist, but imaging and biomarker tools to ensure this referral show low sensitivity and may miss cancer at critical stages. The multivariate index assay (MIA) was designed to improve the detection of ovarian cancer among women undergoing surgery for a pelvic mass. To improve the prediction of benign masses, we undertook the redesign and validation of a second-generation MIA (MIA2G). MIA2G was developed using banked serum samples from a previously published prospective, multisite registry of patients who underwent surgery to remove an adnexal mass. Clinical validity was then established using banked serum samples from the OVA500 trial, a second prospective cohort of adnexal surgery patients. Based on the final pathology results of the OVA500 trial, this intended-use population for MIA2G testing was high risk, with an observed cancer prevalence of 18.7% (92/493). Coded samples were assayed for MIA2G biomarkers by an external clinical laboratory. Then MIA2G results were calculated and submitted to a clinical statistics contract organization for decoding and comparison to MIA results for each subject. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated, among other measures, and stratified by menopausal status, stage, and histologic subtype. Three MIA markers (cancer antigen 125, transferrin, and apolipoprotein A-1) and 2 new biomarkers (follicle-stimulating hormone and human epididymis protein 4) were included in MIA2G. A single cut-off separated high and low risk of malignancy regardless of patient menopausal status, eliminating potential for confusion or error. MIA2G specificity (69%, 277/401 [n/N]; 95% confidence interval [CI], 64.4-73.4%) and PPV (40%, 84/208; 95% CI, 33.9-47.2%) were significantly improved over MIA (specificity, 54%, 215/401; 95% CI, 48.7-58.4%, and PPV, 31%, 85/271; 95

Commercial radioimmunoassay for beta subunit of human chorionic gonadotropin: falsely positive determinations due to elevated serum luteinizing hormone

International Nuclear Information System (INIS)

Fowler, J.E. Jr.; Platoff, G.E.; Kubrock, C.A.; Stuzman, R.E.

1982-01-01

Among 17 men who had received seemingly curative treatment for unilateral non-seminomatous germ cell tumors for the testis and who had consistently normal serum human chorionic gonadotropin (HCG) levels at a reference laboratory, 7 (41%) had at least one falsely positive commercial serum HCG determination. To investigate the cause of these falsely positive determinations the authors measured the cross reactivity of luteinizing hormone (LH) and follicle stimulating hormone (FSH) standards in the commercial HCG assay, and studied the relationships between commercial HCG levels and serum LH levels, serum FSH levels and gonadal status in men with and without normal gonadal function. The falsely positive HCG determinations appeared to be due to elevated serum LH levels and cross reactivity of LH in the commercial HCG assay because: 1) there was substantial cross reactivity of the LH standards in the commercial assay, 2) the serum LH was elevated in four of six men with solitary testes, 3) there was a striking correlation between elevated serum LH levels and falsely elevated commercial HCG levels in ten men with solitary or absent testes, and 4) there were no falsely positive HCG determinations in 13 normal men but there were falsely positive HCG determinations in seven of ten anorchid men

A practical approach for the validation of sterility, endotoxin and potency testing of bone marrow mononucleated cells used in cardiac regeneration in compliance with good manufacturing practice

Directory of Open Access Journals (Sweden)

Gola Mauro

2009-09-01

Full Text Available Abstract Background Main scope of the EU and FDA regulations is to establish a classification criterion for advanced therapy medicinal products (ATMP. Regulations require that ATMPs must be prepared under good manufacturing practice (GMP. We have validated a commercial system for the determination of bacterial endotoxins in compliance with EU Pharmacopoeia 2.6.14, the sterility testing in compliance with EU Pharmacopoeia 2.6.1 and a potency assay in an ATMP constituted of mononucleated cells used in cardiac regeneration. Methods For the potency assay, cells were placed in the upper part of a modified Boyden chamber containing Endocult Basal Medium with supplements and transmigrated cells were scored. The invasion index was expressed as the ratio between the numbers of invading cells relative to cell migration through a control insert membrane. For endotoxins, we used a commercially available system based on the kinetic chromogenic LAL-test. Validation of sterility was performed by direct inoculation of TSB and FTM media with the cell product following Eu Ph 2.6.1 guideline. Results and discussion The calculated MVD and endotoxin limit were 780× and 39 EU/ml respectively. The 1:10 and 1:100 dilutions were selected for the validation. For sterility, all the FTM cultures were positive after 3 days. For TSB cultures, Mycetes and B. subtilis were positive after 5 and 3 days respectively. The detection limit was 1-10 colonies. A total of four invasion assay were performed: the calculated invasion index was 28.89 ± 16.82% (mean ± SD. Conclusion We have validated a strategy for endotoxin, sterility and potency testing in an ATMP used in cardiac regeneration. Unlike pharmaceutical products, many stem-cell-based products may originate in hospitals where personnel are unfamiliar with the applicable regulations. As new ATMPs are developed, the regulatory framework is likely to evolve. Meanwhile, existing regulations provide an appropriate structure for

A practical approach for the validation of sterility, endotoxin and potency testing of bone marrow mononucleated cells used in cardiac regeneration in compliance with good manufacturing practice.

Science.gov (United States)

Soncin, Sabrina; Lo Cicero, Viviana; Astori, Giuseppe; Soldati, Gianni; Gola, Mauro; Sürder, Daniel; Moccetti, Tiziano

2009-09-08

Main scope of the EU and FDA regulations is to establish a classification criterion for advanced therapy medicinal products (ATMP). Regulations require that ATMPs must be prepared under good manufacturing practice (GMP). We have validated a commercial system for the determination of bacterial endotoxins in compliance with EU Pharmacopoeia 2.6.14, the sterility testing in compliance with EU Pharmacopoeia 2.6.1 and a potency assay in an ATMP constituted of mononucleated cells used in cardiac regeneration. For the potency assay, cells were placed in the upper part of a modified Boyden chamber containing Endocult Basal Medium with supplements and transmigrated cells were scored. The invasion index was expressed as the ratio between the numbers of invading cells relative to cell migration through a control insert membrane. For endotoxins, we used a commercially available system based on the kinetic chromogenic LAL-test. Validation of sterility was performed by direct inoculation of TSB and FTM media with the cell product following Eu Ph 2.6.1 guideline. The calculated MVD and endotoxin limit were 780x and 39 EU/ml respectively. The 1:10 and 1:100 dilutions were selected for the validation. For sterility, all the FTM cultures were positive after 3 days. For TSB cultures, Mycetes and B. subtilis were positive after 5 and 3 days respectively. The detection limit was 1-10 colonies. A total of four invasion assay were performed: the calculated invasion index was 28.89 +/- 16.82% (mean +/- SD). We have validated a strategy for endotoxin, sterility and potency testing in an ATMP used in cardiac regeneration. Unlike pharmaceutical products, many stem-cell-based products may originate in hospitals where personnel are unfamiliar with the applicable regulations. As new ATMPs are developed, the regulatory framework is likely to evolve. Meanwhile, existing regulations provide an appropriate structure for ensuring the safety and efficacy of the next generation of ATMPs. Personnel

Evaluation of the Clinical Performance of the HPV-Risk Assay Using the VALGENT-3 Panel.

Science.gov (United States)

Polman, N J; Oštrbenk, A; Xu, L; Snijders, P J F; Meijer, C J L M; Poljak, M; Heideman, D A M; Arbyn, M

2017-12-01

Human papillomavirus (HPV) testing is increasingly being incorporated into cervical cancer screening. The Validation of HPV Genotyping Tests (VALGENT) is a framework designed to evaluate the clinical performance of various HPV tests relative to that of the validated and accepted comparator test in a formalized and uniform manner. The aim of this study was to evaluate the clinical performance of the HPV-Risk assay with samples from the VALGENT-3 panel and to compare its performance to that of the clinically validated Hybrid Capture 2 assay (HC2). The VALGENT-3 panel comprises 1,300 consecutive samples from women participating in routine cervical cancer screening and is enriched with 300 samples from women with abnormal cytology. DNA was extracted from original ThinPrep PreservCyt medium aliquots, and HPV testing was performed using the HPV-Risk assay by investigators blind to the clinical data. HPV prevalence was analyzed, and the clinical performance of the HPV-Risk assay for the detection of cervical intraepithelial neoplasia grade 3 or worse (CIN3+) and CIN2 or worse (CIN2+) relative to the performance of HC2 was assessed. The sensitivity of the HPV-Risk assay for the detection of CIN3+ was similar to that of HC2 (relative sensitivity, 1.00; 95% confidence interval [CI], 0.95 to 1.05; P = 1.000), but the specificity of the HPV-Risk assay was significantly higher than that of HC2 (relative specificity, 1.02; 95% CI, 1.01 to 1.04; P performance of the HPV-Risk assay for the detection of CIN3+ and CIN2+ was noninferior to that of HC2, with all P values being ≤0.006. In conclusion, the HPV-Risk assay demonstrated noninferiority to the clinically validated HC2 by the use of samples from the VALGENT-3 panel for test validation and comparison. Copyright © 2017 Polman et al.

Validation of an enzyme-linked immunosorbent assay (ELISA) for the measurement of canine S100A12.

Science.gov (United States)

Heilmann, Romy M; Cranford, Shannon M; Ambrus, Andy; Grützner, Niels; Schellenberg, Stefan; Ruaux, Craig G; Suchodolski, Jan S; Steiner, Jörg M

2016-03-01

Canine S100 calcium-binding protein A12 (cS100A12) shows promise as biomarker of inflammation in dogs. A previously developed cS100A12-radioimmunoassay (RIA) requires radioactive tracers and is not sensitive enough for fecal cS100A12 concentrations in 79% of tested healthy dogs. An ELISA assay may be more sensitive than RIA and does not require radioactive tracers. The purpose of the study was to establish a sandwich ELISA for serum and fecal cS100A12, and to establish reference intervals (RI) for normal healthy canine serum and feces. Polyclonal rabbit anti-cS100A12 antibodies were generated and tested by Western blotting and immunohistochemistry. A sandwich ELISA was developed and validated, including accuracy and precision, and agreement with cS100A12-RIA. The RI, stability, and biologic variation in fecal cS100A12, and the effect of corticosteroids on serum cS100A12 were evaluated. Lower detection limits were 5 μg/L (serum) and 1 ng/g (fecal), respectively. Intra- and inter-assay coefficients of variation were ≤ 4.4% and ≤ 10.9%, respectively. Observed-to-expected ratios for linearity and spiking recovery were 98.2 ± 9.8% (mean ± SD) and 93.0 ± 6.1%, respectively. There was a significant bias between the ELISA and the RIA. The RI was 49-320 μg/L for serum and 2-484 ng/g for fecal cS100A12. Fecal cS100A12 was stable for 7 days at 23, 4, -20, and -80°C; biologic variation was negligible but variation within one fecal sample was significant. Corticosteroid treatment had no clinically significant effect on serum cS100A12 concentrations. The cS100A12-ELISA is a precise and accurate assay for serum and fecal cS100A12 in dogs. © 2016 American Society for Veterinary Clinical Pathology.

Short communication: identification of a novel HIV type 1 subtype H/J recombinant in Canada with discordant HIV viral load (RNA) values in three different commercial assays.

Science.gov (United States)

Kim, John E; Beckthold, Brenda; Chen, Zhaoxia; Mihowich, Jennifer; Malloch, Laurie; Gill, Michael John

2007-11-01

The presence of HIV-1 non-B subtypes is increasing worldwide. This poses challenges to commercial diagnostic and viral load (RNA) monitoring tests that are predominantly based on HIV-1 subtype B strains. Based on phylogenetic analysis of the gag, pol, and env gene regions, we describe the first HIV-1 H/J recombinant in Canada that presented divergent viral load values. DNA sequence analysis of the gag gene region further revealed that genetic diversity between this H/J recombinant and the primers and probes used in the bio-Merieux Nuclisens HIV-1 QT (Nuclisens) and Roche Amplicor Monitor HIV-1, v1.5 (Monitor) viral RNA assays can erroneously lead to undetectable viral load values. This observation appears to be more problematic in the Nuclisens assay. In light of increasing genetic diversity in HIV worldwide we recommend that DNA sequencing of HIV, especially in the gag gene region targeted by primers and probes used in molecular diagnostic and viral load tests, be incorporated into clinical monitoring practices.

Physical standards and valid caibration

International Nuclear Information System (INIS)

Smith, D.B.

1975-01-01

The desire for improved nuclear material safeguards has led to the development and use of a number and techniques and instruments for the nondestructive assay (NDA) of special nuclear material. Sources of potential bias in NDA measurements are discussed and methods of eliminating the effects of bias in assay results are suggested. Examples are given of instruments in which these methods have been successfully applied. The results of careful attention to potential sources of assay bias are a significant reduction in the number and complexity of standards required for valid instrument calibration and more credible assay results. (auth)

Commercial Supersonics Technology Project - Status of Airport Noise

Science.gov (United States)

Bridges, James

2016-01-01

The Commercial Supersonic Technology Project has been developing databases, computational tools, and system models to prepare for a level 1 milestone, the Low Noise Propulsion Tech Challenge, to be delivered Sept 2016. Steps taken to prepare for the final validation test are given, including system analysis, code validation, and risk reduction testing.

Nanoparticle-assay marker interaction: effects on nanotoxicity assessment

International Nuclear Information System (INIS)

Zhao, Xinxin; Xiong, Sijing; Huang, Liwen Charlotte; Ng, Kee Woei; Loo, Say Chye Joachim

2015-01-01

Protein-based cytotoxicity assays such as lactate dehydrogenase (LDH) and tumor necrosis factor-alpha (TNF-α) are commonly used in cytotoxic evaluation of nanoparticles (NPs) despite numerous reports on possible interactions with protein markers in these assays that can confound the results obtained. In this study, conventional cytotoxicity assays where assay markers may (LDH and TNF- α) or may not (PicoGreen and WST-8) come into contact with NPs were used to evaluate the cytotoxicity of NPs. The findings revealed selective interactions between negatively charged protein assay markers (LDH and TNF- α) and positively charged ZnO NPs under abiotic conditions. The adsorption and interaction with these protein assay markers were strongly influenced by surface charge, concentration, and specific surface area of the NPs, thereby resulting in less than accurate cytotoxic measurements, as observed from actual cell viability measurements. An improved protocol for LDH assay was, therefore, proposed and validated by eliminating any effects associated with protein–particle interactions. In view of this, additional measures and precautions should be taken when evaluating cytotoxicity of NPs with standard protein-based assays, particularly when they are of opposite charges

Nanoparticle-assay marker interaction: effects on nanotoxicity assessment

Energy Technology Data Exchange (ETDEWEB)

Zhao, Xinxin; Xiong, Sijing; Huang, Liwen Charlotte; Ng, Kee Woei, E-mail: kwng@ntu.edu.sg; Loo, Say Chye Joachim, E-mail: joachimloo@ntu.edu.sg [Nanyang Technological University, School of Materials Science and Engineering (Singapore)

2015-01-15

Protein-based cytotoxicity assays such as lactate dehydrogenase (LDH) and tumor necrosis factor-alpha (TNF-α) are commonly used in cytotoxic evaluation of nanoparticles (NPs) despite numerous reports on possible interactions with protein markers in these assays that can confound the results obtained. In this study, conventional cytotoxicity assays where assay markers may (LDH and TNF- α) or may not (PicoGreen and WST-8) come into contact with NPs were used to evaluate the cytotoxicity of NPs. The findings revealed selective interactions between negatively charged protein assay markers (LDH and TNF- α) and positively charged ZnO NPs under abiotic conditions. The adsorption and interaction with these protein assay markers were strongly influenced by surface charge, concentration, and specific surface area of the NPs, thereby resulting in less than accurate cytotoxic measurements, as observed from actual cell viability measurements. An improved protocol for LDH assay was, therefore, proposed and validated by eliminating any effects associated with protein–particle interactions. In view of this, additional measures and precautions should be taken when evaluating cytotoxicity of NPs with standard protein-based assays, particularly when they are of opposite charges.

Nanoparticle-assay marker interaction: effects on nanotoxicity assessment

Science.gov (United States)

Zhao, Xinxin; Xiong, Sijing; Huang, Liwen Charlotte; Ng, Kee Woei; Loo, Say Chye Joachim

2015-01-01

Protein-based cytotoxicity assays such as lactate dehydrogenase (LDH) and tumor necrosis factor-alpha (TNF-α) are commonly used in cytotoxic evaluation of nanoparticles (NPs) despite numerous reports on possible interactions with protein markers in these assays that can confound the results obtained. In this study, conventional cytotoxicity assays where assay markers may (LDH and TNF- α) or may not (PicoGreen and WST-8) come into contact with NPs were used to evaluate the cytotoxicity of NPs. The findings revealed selective interactions between negatively charged protein assay markers (LDH and TNF- α) and positively charged ZnO NPs under abiotic conditions. The adsorption and interaction with these protein assay markers were strongly influenced by surface charge, concentration, and specific surface area of the NPs, thereby resulting in less than accurate cytotoxic measurements, as observed from actual cell viability measurements. An improved protocol for LDH assay was, therefore, proposed and validated by eliminating any effects associated with protein-particle interactions. In view of this, additional measures and precautions should be taken when evaluating cytotoxicity of NPs with standard protein-based assays, particularly when they are of opposite charges.

A novel reporter system for neutralizing and enhancing antibody assay against dengue virus.

Science.gov (United States)

Song, Ke-Yu; Zhao, Hui; Jiang, Zhen-You; Li, Xiao-Feng; Deng, Yong-Qiang; Jiang, Tao; Zhu, Shun-Ya; Shi, Pei-Yong; Zhang, Bo; Zhang, Fu-Chun; Qin, E-De; Qin, Cheng-Feng

2014-02-18

Dengue virus (DENV) still poses a global public health threat, and no vaccine or antiviral therapy is currently available. Antibody plays distinct roles in controlling DENV infections. Neutralizing antibody is protective against DENV infection, whereas sub-neutralizing concentration of antibody can increase DENV infection, termed antibody-dependent enhancement (ADE). Plaque-based assay represents the most widely accepted method measuring neutralizing or enhancing antibodies. In this study, a novel reporter virus-based system was developed for measuring neutralization and ADE activity. A stable Renilla luciferase reporter DENV (Luc-DENV) that can produce robust luciferase signals in BHK-21 and K562 cells were used to establish the assay and validated against traditional plaque-based assay. Luciferase value analysis using various known DENV-specific monoclonal antibodies showed good repeatability and a well linear correlation with conventional plaque-based assays. The newly developed assay was finally validated with clinical samples from infected animals and individuals. This reporter virus-based assay for neutralizing and enhancing antibody evaluation is rapid, lower cost, and high throughput, and will be helpful for laboratory detection and epidemiological investigation for DENV antibodies.

Alkaline comet assay in liver and stomach, and micronucleus assay in bone marrow, from rats treated with 2-acetylaminofluorene, azidothymidine, cisplatin, or isobutyraldehyde.

Science.gov (United States)

Kraynak, A R; Barnum, J E; Cunningham, C L; Ng, A; Ykoruk, B A; Bennet, B; Stoffregen, D; Merschman, M; Freeland, E; Galloway, S M

2015-07-01

As part of the Japanese Center for the Validation of Alternative Methods (JaCVAM) initiative international validation study of the in vivo rat alkaline comet assay (comet assay), we examined the ability of the assay to determine the genotoxicity of 2-acetylaminofluorene (AAF), azidothymidine (AZT), cisplatin (CPN), and isobutyraldehyde (IBA) in liver and glandular stomach of male Sprague-Dawley rats. Rats were given oral doses of test compound or control once daily for three days. High dose levels were approximately maximum tolerated doses and were based on preliminary range-finding studies. Tissues were harvested 3h after the final dose (48h after the initial dose). A bone marrow micronucleus assay (MN) was also conducted on the rats treated with AZT, CPN, and IBA. Acute toxic effects of treatment were determined primarily through histomorphologic analysis of liver and stomach but also by body weight and serum liver enzyme changes. The comet assay was conducted on fresh tissue preparations but frozen samples from two studies were also assayed. Statistically significant dose-related differences in comet % DNA in tail were found in liver and stomach for the genotoxin AZT and in liver for the genotoxin CPN, but not in liver or stomach for the non-genotoxin IBA. Statistically significant differences in % DNA in tail were measured in liver for the low and mid dose of the genotoxin AAF, but not the high dose. The comet assays of frozen liver suspensions from CPN- and AAF-treated rats yielded comparable results to the assays of fresh preparations. There were no indications of significant toxicity induced by any treatment. The micronucleus assay was positive for CPN and AZT and negative for IBA. In conclusion, the in vivo comet assay is capable of detecting genotoxic effects of a variety of chemicals and may fill an important role in the genotoxicity test battery. Copyright © 2015 Elsevier B.V. All rights reserved.

Assessment of Quality of Assay Data on Drill Samples from Golden ...

African Journals Online (AJOL)

The success of a mining company is dependent on the integrity of the resource database. The quality of assay data and thus the validity of the database can only be guaranteed when appropriate sampling and assaying protocols have been implemented. It is necessary to convince investors and project financiers that ...

Harmonization of radiobiological assays: why and how?

International Nuclear Information System (INIS)

Prasanna, Pataje G.

2014-01-01

The International Atomic Energy Agency has made available a technical manual for cytogenetic biodosimetry assays (dicentric chromosome aberration (DCA) and cytokinesis-block micronucleus (CBMN) assays) used for radiation dose assessment in radiation accidents. The International Standardization Organization, which develops standards and guidelines, also provides an avenue for laboratory accreditation, has developed guidelines and recommendations for performing cytogenetic biodosimetry assays. Harmonization of DCA and CBMN assays, has improved their accuracy. Double-blinded inter-laboratory comparison studies involving several networks have further validated DCA and CBMN assays and improved the confidence in their potential use for radiation dose assessment in mass casualties. This kind of international harmonization is lacking for pre-clinical radiobiology assays. The widely used pre-clinical assays that are relatively important to set stage for clinical trials include clonogenic assays, flow-cytometry assays, apoptotic assays, and tumor regression and growth delay assays. However, significant inter-laboratory variations occur with respect to data among laboratories. This raises concerns on the reliability and reproducibility of preclinical data that drives further development and translation. Lack of reproducibility may stem from a variety of factors such as poor scientist training, less than optimal experimental design, inadequate description of methodology, and impulse to publish only the positive data etc. Availability of technical manuals, standard operating procedures, accreditation avenues for laboratories performing such assays, inter-laboratory comparisons, and use of standardized protocols are necessary to enhance reliability and reproducibility. Thus, it is important that radiobiological assays are harmonized for laboratory protocols to ensure successful translation of pre-clinical research on radiation effect modulators to help design clinic trials with

Comparative evaluation of three automated systems for DNA extraction in conjunction with three commercially available real-time PCR assays for quantitation of plasma Cytomegalovirus DNAemia in allogeneic stem cell transplant recipients.

Science.gov (United States)

Bravo, Dayana; Clari, María Ángeles; Costa, Elisa; Muñoz-Cobo, Beatriz; Solano, Carlos; José Remigia, María; Navarro, David

2011-08-01

Limited data are available on the performance of different automated extraction platforms and commercially available quantitative real-time PCR (QRT-PCR) methods for the quantitation of cytomegalovirus (CMV) DNA in plasma. We compared the performance characteristics of the Abbott mSample preparation system DNA kit on the m24 SP instrument (Abbott), the High Pure viral nucleic acid kit on the COBAS AmpliPrep system (Roche), and the EZ1 Virus 2.0 kit on the BioRobot EZ1 extraction platform (Qiagen) coupled with the Abbott CMV PCR kit, the LightCycler CMV Quant kit (Roche), and the Q-CMV complete kit (Nanogen), for both plasma specimens from allogeneic stem cell transplant (Allo-SCT) recipients (n = 42) and the OptiQuant CMV DNA panel (AcroMetrix). The EZ1 system displayed the highest extraction efficiency over a wide range of CMV plasma DNA loads, followed by the m24 and the AmpliPrep methods. The Nanogen PCR assay yielded higher mean CMV plasma DNA values than the Abbott and the Roche PCR assays, regardless of the platform used for DNA extraction. Overall, the effects of the extraction method and the QRT-PCR used on CMV plasma DNA load measurements were less pronounced for specimens with high CMV DNA content (>10,000 copies/ml). The performance characteristics of the extraction methods and QRT-PCR assays evaluated herein for clinical samples were extensible at cell-based standards from AcroMetrix. In conclusion, different automated systems are not equally efficient for CMV DNA extraction from plasma specimens, and the plasma CMV DNA loads measured by commercially available QRT-PCRs can differ significantly. The above findings should be taken into consideration for the establishment of cutoff values for the initiation or cessation of preemptive antiviral therapies and for the interpretation of data from clinical studies in the Allo-SCT setting.

Computer-determined assay time based on preset precision

International Nuclear Information System (INIS)

Foster, L.A.; Hagan, R.; Martin, E.R.; Wachter, J.R.; Bonner, C.A.; Malcom, J.E.

1994-01-01

Most current assay systems for special nuclear materials (SNM) operate on the principle of a fixed assay time which provides acceptable measurement precision without sacrificing the required throughput of the instrument. Waste items to be assayed for SNM content can contain a wide range of nuclear material. Counting all items for the same preset assay time results in a wide range of measurement precision and wastes time at the upper end of the calibration range. A short time sample taken at the beginning of the assay could optimize the analysis time on the basis of the required measurement precision. To illustrate the technique of automatically determining the assay time, measurements were made with a segmented gamma scanner at the Plutonium Facility of Los Alamos National Laboratory with the assay time for each segment determined by counting statistics in that segment. Segments with very little SNM were quickly determined to be below the lower limit of the measurement range and the measurement was stopped. Segments with significant SNM were optimally assays to the preset precision. With this method the total assay time for each item is determined by the desired preset precision. This report describes the precision-based algorithm and presents the results of measurements made to test its validity

Alternatives to animal testing: research, trends, validation, regulatory acceptance.

Science.gov (United States)

Huggins, Jane

2003-01-01

Current trends and issues in the development of alternatives to the use of animals in biomedical experimentation are discussed in this position paper. Eight topics are considered and include refinement of acute toxicity assays; eye corrosion/irritation alternatives; skin corrosion/irritation alternatives; contact sensitization alternatives; developmental/reproductive testing alternatives; genetic engineering (transgenic) assays; toxicogenomics; and validation of alternative methods. The discussion of refinement of acute toxicity assays is focused primarily on developments with regard to reduction of the number of animals used in the LD(50) assay. However, the substitution of humane endpoints such as clinical signs of toxicity for lethality in these assays is also evaluated. Alternative assays for eye corrosion/irritation as well as those for skin corrosion/irritation are described with particular attention paid to the outcomes, both successful and unsuccessful, of several validation efforts. Alternative assays for contact sensitization and developmental/reproductive toxicity are presented as examples of methods designed for the examination of interactions between toxins and somewhat more complex physiological systems. Moreover, genetic engineering and toxicogenomics are discussed with an eye toward the future of biological experimentation in general. The implications of gene manipulation for research animals, specifically, are also examined. Finally, validation methods are investigated as to their effectiveness, or lack thereof, and suggestions for their standardization and improvement, as well as implementation are reviewed.

Evaluation of a radioreceptor assay for TSH receptor autoantibodies

Energy Technology Data Exchange (ETDEWEB)

Rootwelt, K.

1988-02-01

A commercial radioreceptor assay for TSH receptor autoantibodies (TRAb), based on solubilized porcine receptor and purified radio-iodinated bovine TSH, was tested in 264 subjects with a variety of thyroid disorders. The sensitivity of the assay for the detection of hyperthyroid Graves' disease was 91%. The assay specificity for Graves' disease was 95%. With the exception of one patient with Hashimoto's disease and one patient with de Quervain's subacute thyroiditis no subjects other than Graves' patients had detectable TRAb. Thus purely blocking TSII receptor autoantibodies were not detected with the assay. One female with thyroxine-treated idiopathic primary hypothyroidism who had given birth to two children with transiently elevated TSH, was found to have a circulating TSH-binding substance that resulted in an abnormally negative TRAb value, and highly discrepant results when TSH was measured with a double antibody TSH radioimmunoassay and an immunoradiometric assay. The TSH-binding substance was precipitated like a protein, but was not IgG. Similar findings have not previously been reported.

Evaluation of the Thermo Scientific SureTect Listeria monocytogenes Assay.

Science.gov (United States)

Cloke, Jonathan; Leon-Velarde, Carlos; Larson, Nathan; Dave, Keron; Evans, Katharine; Crabtree, David; Hughes, Annette; Hopper, Craig; Simpson, Helen; Withey, Sophie; Oleksiuk, Milena; Holopainen, Jani; Wickstrand, Nina; Kauppinen, Mikko

2014-01-01

The Thermo Scientific SureTect Listeria monocytogenes Assay is a new real-time PCR assay for the detection of Listeria monocytogenes in food and environmental samples. This assay was validated using the AOAC Research Institute (AOAC-RI) Performance Tested Methods program in comparison to the reference method detailed in International Organization for Standardization 11290-1:1996, including Amendment 1:2004 with the following foods and food contact surfaces: smoked salmon, processed cheese, fresh bagged spinach, fresh cantaloupe, cooked prawns (chilled product), cooked sliced turkey meat (chilled product), ice cream, pork frankfurters, salami, ground raw beef meat (12% fat), plastic, and stainless steel. All matrixes were tested by Thermo Fisher Scientific, Microbiology Division, Basingstoke, UK. In addition, three matrixes (pork frankfurters, bagged lettuce, and stainless steel) were analyzed independently as part of the AOAC-RI controlled laboratory study by the University of Guelph, Canada. Using probability of detection (POD) statistical analysis, a significant difference was demonstrated between the candidate and reference methods for salami, cooked sliced turkey and ice cream in favor of the SureTect assay. For all other matrixes, no significant difference by POD was seen between the two methods during the study. Inclusivity and exclusivity testing was also conducted with 53 and 30 isolates, respectively, which demonstrated that the SureTect assay was able to detect all serotypes of L. monocytogenes. None of the exclusivity isolates analyzed were detected by the SureTect assay. Ruggedness testing was conducted to evaluate the performance of the assay with specific method deviations outside the recommended parameters open to variation, i.e., enrichment time and temperature and lysis temperature, which demonstrated that the assay gave reliable performance. Accelerated stability testing was also conducted, validating the assay shelf life.

Variability of assay methods for total and free PSA after WHO standardization.

Science.gov (United States)

Foj, L; Filella, X; Alcover, J; Augé, J M; Escudero, J M; Molina, R

2014-03-01

The variability of total PSA (tPSA) and free PSA (fPSA) results among commercial assays has been suggested to be decreased by calibration to World Health Organization (WHO) reference materials. To characterize the current situation, it is necessary to know its impact in the critical cutoffs used in clinical practice. In the present study, we tested 167 samples with tPSA concentrations of 0 to 20 μg/L using seven PSA and six fPSA commercial assays, including Access, ARCHITECT i2000, ADVIA Centaur XP, IMMULITE 2000, Elecsys, and Lumipulse G1200, in which we only measured tPSA. tPSA and fPSA were measured in Access using the Hybritech and WHO calibrators. Passing-Bablok analysis was performed for PSA, and percentage of fPSA with the Hybritech-calibrated access comparison assay. For tPSA, relative differences were more than 10 % at 0.2 μg/L for ARCHITECT i2000, and at a critical concentration of 3, 4, and 10 μg/L, the relative difference was exceeded by ADVIA Centaur XP and WHO-calibrated Access. For percent fPSA, at a critical concentration of 10 %, the 10 % relative difference limit was exceeded by IMMULITE 2000 assay. At a critical concentration of 20 and 25 %, ADVIA Centaur XP, ARCHITECT i2000, and IMMULITE 2000 assays exceeded the 10 % relative difference limit. We have shown significant discordances between assays included in this study despite advances in standardization conducted in the last years. Further harmonization efforts are required in order to obtain a complete clinical concordance.

Selection of matched pair of monoclonal antibodies for development of immunoradiometric assay (IRMA) : our experience with IRMA of TSH

International Nuclear Information System (INIS)

Kadwad, V.B.; Jyotsna, N.; Sivaprasad, N.

1998-01-01

Full text: In immunoradiometricassay (IRMA) two antibodies raised against two different epitopes of the same antigen are used, one bound to a solid phase (capture antibody) and the other labelled with 125 I (detector antibody). The development of any IRMA thus involves proper selection of the capture and detector antibody, preparation of solid phase, labelling of the antibody and assay optimization. Extensive studies have been carried out on these aspects in our laboratory with greater emphasis on the behavior of different pairs of antibodies as sandwich partners : monoclonal-monoclonal and monoclonal-polyclonal antibodies. The parameters studied include the ease of radio-iodination of different monoclonal antibodies, the effect of interchange of capture and detector antibody etc. Keeping TSH antibody as a model, two different monoclonal antibodies, a polyclonal antibody and a tracer from a commercial TSH IRMA kit were used in this study. Based on our studies an assay procedure for in-house IRMA of TSH has been developed with a sensitivity of 0.1 μIU/ml and validated

Preliminary validation of assays to measure parameters of calcium metabolism in captive Asian and African elephants in western Europe.

Science.gov (United States)

van Sonsbeek, Gerda R; van der Kolk, Johannes H; van Leeuwen, Johannes P T M; Schaftenaar, Willem

2011-05-01

Hypocalcemia is a well known cause of dystocia in animals, including elephants in captivity. In order to study calcium metabolism in elephants, it is of utmost importance to use properly validated assays, as these might be prone to specific matrix effects in elephant blood. The aim of the current study was to conduct preliminary work for validation of various parameters involved in calcium metabolism in both blood and urine of captive elephants. Basal values of these parameters were compared between Asian elephants (Elephas maximus) and African elephants (Loxodonta africana). Preliminary testing of total calcium, inorganic phosphorus, and creatinine appeared valid for use in plasma and creatinine in urine in both species. Furthermore, measurements of bone alkaline phosphatase and N-terminal telopeptide of type I collagen appeared valid for use in Asian elephants. Mean heparinized plasma ionized calcium concentration and pH were not significantly affected by 3 cycles of freezing and thawing. Storage at 4 °C, room temperature, and 37 °C for 6, 12, and 24 hr did not alter the heparinized plasma ionized calcium concentration in Asian elephants. The following linear regression equation using pH (range: 6.858-7.887) and ionized calcium concentration in heparinized plasma was utilized: iCa(7.4) (mmol/l) = -2.1075 + 0.3130·pH(actual) + 0.8296·iCa(actual) (mmol/l). Mean basal values for pH and plasma in Asian elephant whole blood were 7.40 ± 0.048 and 7.49 ± 0.077, respectively. The urinary specific gravity and creatinine concentrations in both Asian and African elephants were significantly correlated and both were significantly lower in Asian elephants. © 2011 The Author(s)

Hypocretin measurement: shelf age of radioimmunoassay kit, but not freezer time, influences assay variability.

Science.gov (United States)

Keating, Glenda; Bliwise, Donald L; Saini, Prabhjyot; Rye, David B; Trotti, Lynn Marie

2017-09-01

The hypothalamic peptide hypocretin 1 (orexin A) may be assayed in cerebrospinal fluid to diagnose narcolepsy type 1. This testing is not commercially available, and factors contributing to assay variability have not previously been comprehensively explored. In the present study, cerebrospinal fluid hypocretin concentrations were determined in duplicate in 155 patient samples, across a range of sleep disorders. Intra-assay variability of these measures was analyzed. Inter-assay correlation between samples tested at Emory and at Stanford was high (r = 0.79, p hypocretin values, such that kits closer to expiration exhibit significantly more variability.

Validation of low-volume enrichment protocols for detection of Escherichia coli O157 in raw ground beef components, using commercial kits.

Science.gov (United States)

Ahmed, Imtiaz; Hughes, Denise; Jenson, Ian; Karalis, Tass

2009-03-01

Testing of beef destined for use in ground beef products for the presence of Escherichia coli O157:H7 has become an important cornerstone of control and verification activities within many meat supply chains. Validation of the ability of methods to detect low levels of E. coli O157:H7 is critical to confidence in test systems. Many rapid methods have been validated against standard cultural methods for 25-g samples. In this study, a number of previously validated enrichment broths and commercially available test kits were validated for the detection of low numbers of E. coli O157:H7 in 375-g samples of raw ground beef component matrices using 1 liter of enrichment broth (large-sample:low-volume enrichment protocol). Standard AOAC International methods for 25-g samples in 225 ml of enrichment broth, using the same media, incubation conditions, and test kits, were used as reference methods. No significant differences were detected in the ability of any of the tests to detect low levels of E. coli O157:H7 in samples of raw ground beef components when enriched according to standard or large-sample:low-volume enrichment protocols. The use of large-sample:low-volume enrichment protocols provides cost savings for media and logistical benefits when handling and incubating large numbers of samples.

MS transport assays for γ-aminobutyric acid transporters--an efficient alternative for radiometric assays.

Science.gov (United States)

Schmitt, Sebastian; Höfner, Georg; Wanner, Klaus T

2014-08-05

Transport assays for neurotransmitters based on radiolabeled substrates are widely spread and often indispensable in basic research and the drug development process, although the use of radioisotopes is inherently coupled to issues concerning radioactive waste and safety precautions. To overcome these disadvantages, we developed mass spectrometry (MS)-based transport assays for γ-aminobutyric acid (GABA), which is the major inhibitory neurotransmitter in the central nervous system (CNS). These "MS Transport Assays" provide all capabilities of [(3)H]GABA transport assays and therefore represent the first substitute for the latter. The performance of our approach is demonstrated for GAT1, the most important GABA transporter (GAT) subtype. As GABA is endogenously present in COS-7 cells employed as hGAT1 expression system, ((2)H6)GABA was used as a substrate to differentiate transported from endogenous GABA. To record transported ((2)H6)GABA, a highly sensitive, short, robust, and reliable HILIC-ESI-MS/MS quantification method using ((2)H2)GABA as an internal standard was developed and validated according to the Center for Drug Evaluation and Research (CDER) guidelines. Based on this LC-MS quantification, a setup to characterize hGAT1 mediated ((2)H6)GABA transport in a 96-well format was established, that enables automated processing and avoids any sample preparation. The K(m) value for ((2)H6)GABA determined for hGAT1 is in excellent agreement with results obtained from [(3)H]GABA uptake assays. In addition, the established assay format enables efficient determination of the inhibitory potency of GAT1 inhibitors, is capable of identifying those inhibitors transported as substrates, and furthermore allows characterization of efflux. The approach described here combines the strengths of LC-MS/MS with the high efficiency of transport assays based on radiolabeled substrates and is applicable to all GABA transporter subtypes.

Evaluation of nicotine in tobacco-free-nicotine commercial products.

Science.gov (United States)

Hellinghausen, Garrett; Lee, Jauh T; Weatherly, Choyce A; Lopez, Diego A; Armstrong, Daniel W

2017-06-01

Recently, a variety of new tobacco-free-nicotine, TFN, products have been commercialized as e-liquids. Tobacco-derived nicotine contains predominantly (S)-(-)-nicotine, whereas TFN products may not. The TFN products are said to be cleaner, purer substances, devoid of toxic components that come from the tobacco extraction process. A variety of commercial tobacco and TFN products were analyzed to identify the presence and composition of each nicotine enantiomer. A rapid and effective enantiomeric separation of nicotine has been developed using a modified macrocyclic glycopeptide bonded to superficially porous particles. The enantiomeric assay can be completed in nicotine, which is present in much greater quantities in commercial TFN products compared to commercial tobacco-derived products. Such studies are required by the FDA for new enantiomeric pharmacological products. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Case study on human α1-antitrypsin: Recombinant protein titers obtained by commercial ELISA kits are inaccurate

DEFF Research Database (Denmark)

Hansen, Henning Gram; Kildegaard, Helene Faustrup; Min Lee, Gyun

2016-01-01

Accurate titer determination of recombinant proteins is crucial for evaluating protein production cell lines and processes. Even though enzyme-linked immunosorbent assay (ELISA) is the most widely used assay for determining protein titer, little is known about the accuracy of commercially available...... ELISA kits. We observed that estimations of recombinant human ø1-antitrypsin (rø1AT) titer by Coomassie-stained SDS-PAGE gels did not correspond to previously obtained titers obtained by a commercially available ELISA kit. This prompted us to develop two independent quantification assays based...... on biolayer interferometry and reversed-phase high-performance liquid chromatography. We compared the rø1AT titer obtained by these assays with three different off-the-shelf ELISA kits and found that the ELISA kits led to inconsistent results. The data presented here show that recombinant protein titers...

A validated specific stability-indicating RP-HPLC assay method for Ambrisentan and its related substances.

Science.gov (United States)

Narayana, M B V; Chandrasekhar, K B; Rao, B M

2014-09-01

A validated specific stability-indicating reverse-phase liquid chromatographic method was developed for the quantitative determination of Ambrisentan as well as its related substances in bulk samples, pharmaceutical dosage forms in the presence of degradation products and its related impurities. Forced degradation studies were performed on bulk samples of Ambrisentan as per the ICH-prescribed stress conditions using acid, base, oxidative, thermal stress and photolytic degradation to show the stability-indicating power of the LC method. Significant degradation in acidic, basic stress conditions was observed and no degradation was observed in other stress conditions. The chromatographic method was optimized using the samples generated from the forced degradation studies and the impurity-spiked solution. Good resolution between the peaks corresponds to Ambrisentan-related impurities and degradation products from the analyte were achieved on a SunFire C18 column using a mobile phase consisting of a mixture of potassium dihydrogen orthophosphate at a pH adjusted to 2.5 with ortho-phosphoric acid in water and a mixture of acetonitrile:methanol using a simple linear gradient. The detection was carried out at 225 nm. The limit of detection and the limit of quantification for the Ambrisentan and its related impurities were established. The stressed test solutions were assayed against the qualified working standard of Ambrisentan and the mass balance in each case was between 98.9 and 100.3%, indicating that the developed LC method was stability indicating. Validation of the developed LC method was carried out as per the ICH requirements. The developed method was found to be suitable to check the quality of bulk samples of Ambrisentan at the time of batch release and also during its storage (long-term and accelerated stability). © The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

An interlaboratory transfer of a multi-analyte assay between continents.

Science.gov (United States)

Georgiou, Alexandra; Dong, Kelly; Hughes, Stephen; Barfield, Matthew

2015-01-01

Alex has worked at GlaxoSmithKline for the past 15 years and currently works within the bioanalytical and toxicokinetic group in the United Kingdom. Alex's role in previous years has been the in-house support of preclinical and clinical bioanalysis, from method development through to sample analysis activities as well as acting as PI for GLP bioanalysis and toxicokinetics. For the past two years, Alex has applied this analytical and regulatory experience to focus on the outsourcing of preclinical bioanalysis, toxicokinetics and clinical bioanalysis, working closely with multiple bioanalytical and in-life CRO partners worldwide. Alex works to support DMPK and Safety Assessment outsourcing activities for GSK across multiple therapeutic areas, from the first GLP study through to late stage clinical PK studies. Transfer and cross-validation of an existing analytical assay between a laboratory providing current analytical support, and a laboratory needed for new or additional support, can present the bioanalyst with numerous challenges. These challenges can be technical or logistical in nature and may prove to be significant when transferring an assay between laboratories in different continents. Part of GlaxoSmithKline's strategy to improve confidence in providing quality data, is to cross-validate between laboratories. If the cross-validation fails predefined acceptance criteria, then a subsequent investigation would follow. This may also prove to be challenging. The importance of thorough planning and good communication throughout assay transfer, cross-validation and any subsequent investigations is illustrated in this case study.

Inter-laboratory validation of the measurement of follicle stimulating hormone (FSH after various lengths of frozen storage

Directory of Open Access Journals (Sweden)

Behr Barry

2010-11-01

Full Text Available Abstract Background Serum follicle stimulating hormone (FSH levels are used clinically to evaluate infertility, pituitary and gonadal disorders. With increased frequency of research collaborations across institutions, it is essential that inter-laboratory validation is addressed. Methods An inter-laboratory validation of three commercial FSH immunoassays was performed with human serum samples of varying frozen storage length (2 batches of 15 samples each at -25 degree C. Percentage differences and Bland-Altman limits of agreement were calculated. Results The inter- and intra-laboratory consistency of FSH values with the same assay manufacturer was much higher after shorter-term storage (frozen for less than 11 months, mean percentage degradation less than 4% than after long-term storage (2-3 years, mean percentage degradation = 23%. Comparing assay results from different manufacturers, there was similar overall long term degradation as seen with the same manufacturer (-25%, however the degradation was greater when the original FSH was greater than 20 mIU/mL relative to less than 10 mIU/mL (p Conclusion The findings suggest that degradation of serum samples stored between 11 months and 2-3 years at -25 degrees C can lead to unstable FSH measurements. Inter-laboratory variability due to frozen storage time and manufacturer differences in assay results should be accounted for when designing and implementing research or clinical quality control activities involving serum FSH at multiple study sites.

Validated method for the analysis of goji berry, a rich source of zeaxanthin dipalmitate.

Science.gov (United States)

Karioti, Anastasia; Bergonzi, Maria Camilla; Vincieri, Franco F; Bilia, Anna Rita

2014-12-31

In the present study an HPLC-DAD method was developed for the determination of the main carotenoid, zeaxanthin dipalmitate, in the fruits of Lycium barbarum. The aim was to develop and optimize an extraction protocol to allow fast, exhaustive, and repeatable extraction, suitable for labile carotenoid content. Use of liquid N2 allowed the grinding of the fruit. A step of ultrasonication with water removed efficiently the polysaccharides and enabled the exhaustive extraction of carotenoids by hexane/acetone 50:50. The assay was fast and simple and permitted the quality control of a large number of commercial samples including fruits, juices, and a jam. The HPLC method was validated according to ICH guidelines and satisfied the requirements. Finally, the overall method was validated for precision (% RSD ranging between 3.81 and 4.13) and accuracy at three concentration levels. The recovery was between 94 and 107% with RSD values <2%, within the acceptable limits, especially if the difficulty of the matrix is taken into consideration.

Neutron Resonance Transmission Analysis (NRTA): A Nondestructive Assay Technique for the Next Generation Safeguards Initiative’s Plutonium Assay Challenge

Energy Technology Data Exchange (ETDEWEB)

J. W. Sterbentz; D. L. Chichester

2010-12-01

This is an end-of-year report for a project funded by the National Nuclear Security Administration's Office of Nuclear Safeguards (NA-241). The goal of this project is to investigate the feasibility of using Neutron Resonance Transmission Analysis (NRTA) to assay plutonium in commercial light-water-reactor spent fuel. This project is part of a larger research effort within the Next-Generation Safeguards Initiative (NGSI) to evaluate methods for assaying plutonium in spent fuel, the Plutonium Assay Challenge. The first-year goals for this project were modest and included: 1) developing a zero-order MCNP model for the NRTA technique, simulating data results presented in the literature, 2) completing a preliminary set of studies investigating important design and performance characteristics for the NRTA measurement technique, and 3) documentation of this work in an end of the year report (this report). Research teams at Los Alamos National Laboratory (LANL), Lawrence Berkeley National Laboratory (LBNL), Pacific Northwest National Laboratory (PNNL), and at several universities are also working to investigate plutonium assay methods for spent-fuel safeguards. While the NRTA technique is well proven in the scientific literature for assaying individual spent fuel pins, it is a newcomer to the current NGSI efforts studying Pu assay method techniques having just started in March 2010; several analytical techniques have been under investigation within this program for two to three years or more. This report summarizes a nine month period of work.

Laboratory evaluation of commercial interferon preparations

International Nuclear Information System (INIS)

Schoub, B.D.; Lyons, S.F.; Crespi, M.; Chiu, M.-N.; Lomnitzer, R.

1983-01-01

The antiviral, antiproliferative and natural killer-cell (NKC) stimulatory activities of four commercial therapeutic interferon preparations were assayed in a laboratory. The antiviral and antiproliferative activities of each preparation were relatively similar, but an unexpectedly high NKC stimulatory activity was found in one of them. In-house determination of antiviral activity and evaluation of the antiproliferative and NKC stimulation potential of interferon preparations are essential before rational clinical trials of this agent are carried out

Gamma aminobutyric acid radioreceptor assay: a confirmatory quantitative assay for toxaphene in environmental and biological samples

International Nuclear Information System (INIS)

Saleh, M.A.; Blancato, J.N.

1993-01-01

Toxaphene is a complex mixture of polychlorinated monoterpenes, and was found to be acutely and chronically toxic to aquatic and wild life and posed a carcinogenic risk to humans before its ban in 1982. However, it is still found in the environment due to its relative persistence with an estimated half life time of about 10 years in soils. Toxaphenes neurotoxicity is attributed to a few isomers with a mode of action through binding to the chloride channel of the gamma-aminobutyric acid (GABA) receptor ionophore complex. [ 35 S] tertiary butylbicyclophosphorothionate (TBPS) with specific activity higher than 60 Ci/mmole has a high binding affinity to the same sites and is now commercially available and can be used to label the GABA receptor for the development of radioreceptor assay technique. The GABA receptor was prepared by a sequence of ultra centrifugation and dialysis of mammalian (rats, cows, catfish and goats) brain homogenates. The receptor is then labeled with [ 35 S] TBPS and the assay was conducted by measuring the displacement of radioactivity following incubation with the sample containing the analytes. The assay is fast, sensitive and requires very little or no sample preparation prior to the analysis. (Author)

Development and Validation of a TaqMan Real-Time PCR Assay for the Specific Detection and Quantification of Fusarium fujikuroi in Rice Plants and Seeds.

Science.gov (United States)

Carneiro, Greice Amaral; Matić, Slavica; Ortu, Giuseppe; Garibaldi, Angelo; Spadaro, Davide; Gullino, Maria Lodovica

2017-07-01

Bakanae disease, which is caused by the seedborne pathogen Fusarium fujikuroi, is found throughout the world on rice. A TaqMan real-time PCR has been developed on the TEF 1-α gene to detect F. fujikuroi in different rice tissues. Three primer/probe sets were tested. The selected set produced an amplicon of 84 bp and was specific for F. fujikuroi with respect to eight Fusarium species of rice and six other rice common pathogens. The assay was validated for specificity, selectivity, sensitivity, repeatability, and reproducibility. The detection limit was set at 27.5 fg of DNA, which is approximately equivalent to one haploid genome of F. fujikuroi. The developed TaqMan real-time assay was able to efficiently detect and quantify F. fujikuroi from rice culms, leaves, roots, and seeds. At 1 week post-germination (wpg), the pathogen was more diffused in the green tissues, while at 3 wpg it was uniformly spread also in the roots. The highest concentration of F. fujikuroi was measured in the M6 cultivar, which showed around 1,450 fungal cells/g. The assay was sufficiently sensitive to detect a few genomic equivalents in the rice seeds, corresponding to 9.89 F. fujikuroi cells/g. The assay permitted bakanae disease to be detected in asymptomatic tissues at the early rice development stages.

Evaluation of TV commercials using neurophysiological responses.

Science.gov (United States)

Yang, Taeyang; Lee, Do-Young; Kwak, Youngshin; Choi, Jinsook; Kim, Chajoong; Kim, Sung-Phil

2015-04-24

In recent years, neuroscientific knowledge has been applied to marketing as a novel and efficient means to comprehend the cognitive and behavioral aspects of consumers. A number of studies have attempted to evaluate media contents, especially TV commercials using various neuroimaging techniques such as electroencephalography (EEG). Yet neurophysiological examination of detailed cognitive and affective responses in viewers is still required to provide practical information to marketers. Here, this study develops a method to analyze temporal patterns of EEG data and extract affective and cognitive indices such as happiness, surprise, and attention for TV commercial evaluation. Twenty participants participated in the study. We developed the neurophysiological indices for TV commercial evaluation using classification model. Specifically, these model-based indices were customized using individual EEG features. We used a video game for developing the index of attention and four video clips for developing indices of happiness and surprise. Statistical processes including one-way analyses of variance (ANOVA) and the cross validation scheme were used to select EEG features for each index. The EEG features were composed of the combinations of spectral power at selected channels from the cross validation for each individual. The Fisher's linear discriminant classifier (FLDA) was used to estimate each neurophysiological index during viewing four different TV commercials. Post hoc behavioral responses of preference, short-term memory, and recall were measured. Behavioral results showed significant differences for all preference, short-term memory rates, and recall rates between commercials, leading to a 'high-ranked' commercial group and a 'low-ranked' group (P < 0.05). Neural estimation of happiness results revealed a significant difference between the high-ranked and the low-ranked commercials in happiness index (P < 0.01). The order of rankings based on happiness and

A quantitative in vitro assay for the evaluation of phototoxic potential of topically applied materials.

Science.gov (United States)

Tenenbaum, S; DiNardo, J; Morris, W E; Wolf, B A; Schnetzinger, R W

1984-10-01

A quantitative in vitro method for phototoxic evaluation of chemicals has been developed and validated. The assay uses Saccharomyces cerevisiae, seeded in an agar overlay on top of a plate count agar base. 8-Methoxy psoralen is used as a reference standard against which materials are measured. Activity is quantified by cytotoxicity measured as zones of inhibition. Several known phototoxins (heliotropine, lyral, phantolid, and bergamot oil) and photoallergens (6-methyl coumarin and musk ambrette) are used to validate the assay. An excellent correlation is observed between in vivo studies employing Hartley albino guinea pigs and the in vitro assay for several fragrance raw materials and other chemicals. The in vitro assay exhibits a greater sensitivity from 2-500 fold. For three fragrance oils, the in vitro assay detects low levels of photobiological activity while the in vivo assay is negative. Although the in vitro assay does not discriminate between phototoxins and photoallergens, it can be used for screening of raw materials so that reduction in animal usage can be achieved while maintaining the protection of the consumer.

Development of an alpha-fetoprotein and Golgi protein 73 multiplex detection assay using xMAP technology.

Science.gov (United States)

Wu, Yun; Ma, Jie; Wang, Yipeng; Zhang, Yonghong; Hou, Yongjin; Zhang, Chunming; Sun, Huanqin; Sun, Jianping; Wang, Zikang; Li, Ning

2018-04-06

Development of a new method to simultaneously detect Alpha-fetoprotein (AFP) and Golgi protein 73 (GP73) from peripheral blood. Anti human AFP and GP73 monoclonal antibodies was used to develop a sandwich immunity reaction using xMAP technology for the simultaneous detection of plasma AFP and GP73. The assay evaluated the sensitivity, cross reactivity, range of detection, precision, recovery and linearity dilution effect. The assay utilized plasma samples and compared its performance with commercially available Enzyme Linked Immunosorbent Assay (ELISA) kits. The assay was successful in detecting AFP and GP73 simultaneously. Validation experiments demonstrated the limit of detection was AFP 0.006 μg/l and GP73 0.482 μg/l. The functional sensitivity was AFP 0.010 μg/l and GP73 0.640 μg/l. The range of detection was AFP 0.01-50 μg/l and GP73 0.64-100 μg/l. No cross reactivity was observed. The intra- and inter-assay variation for AFP was 0.19-3.46% and 3.1-5.8% and for GP73 was 1.5-3.2% and 1.1-7.6% respectively. The recovery for AFP was 96-106% and GP73 was 89-110%. 80 clinical plasma samples from healthy controls, and patients with liver cirrhosis and Hepatocellular Carcinoma (HCC) were evaluated. For healthy controls (n = 25), the AFP was 2.40 (1.55, 3.30) μg/l and GP73 was 42.60 (39.10, 57.40) μg/l. For patients with liver cirrhosis (n = 19), the AFP was 2.60 (1.70, 4.20) μg/l and GP73 was 136.10 (92.10, 261.70) μg/l, and for HCC patients (n = 36), the AFP was 13.65 (3.35, 158.88) μg/l and GP73 was 186.25 (96.73, 262.03) μg/l. The new assay demonstrated a good correlation with commercially available ELISA kits (correlation coefficients (r) were 0.997 (AFP, p < 0.001) and 0.959 (GP73, p < 0.001). The method demonstrated a sensitive, effective and accurate method for the simultaneous detection of AFP and GP73, and could be used clinically for routine detection and monitoring of patients with chronic hepatitis B

DTU PMU Laboratory Development - Testing and Validation

DEFF Research Database (Denmark)

Garcia-Valle, Rodrigo; Yang, Guang-Ya; Martin, Kenneth E.

2010-01-01

This is a report of the results of phasor measurement unit (PMU) laboratory development and testing done at the Centre for Electric Technology (CET), Technical University of Denmark (DTU). Analysis of the PMU performance first required the development of tools to convert the DTU PMU data into IEEE...... standard, and the validation is done for the DTU-PMU via a validated commercial PMU. The commercial PMU has been tested from the authors' previous efforts, where the response can be expected to follow known patterns and provide confirmation about the test system to confirm the design and settings....... In a nutshell, having 2 PMUs that observe same signals provides validation of the operation and flags questionable results with more certainty. Moreover, the performance and accuracy of the DTU-PMU is tested acquiring good and precise results, when compared with a commercial phasor measurement device, PMU-1....

An ARGS-aggrecan assay for analysis in blood and synovial fluid

DEFF Research Database (Denmark)

Larsson, S; Lohmander, Stefan; Struglics, A

2014-01-01

OBJECTIVE: To validate a modified ligand-binding assay for the detection of aggrecanase generated aggrecan fragments with the ARGS neoepitope in synovial fluid (SF) and blood, and to verify the identity of aggrecan fragments found in blood. DESIGN: An enzyme-linked immunosorbent assay (ELISA....... Aggrecan was purified from serum and plasma pools and analysed by Western blot. RESULTS: The limits of quantification for the ARGS-aggrecan assay was between 0.2 and 0.025 pmol ARGS/ml, and the sensitivity of the assay was improved two-fold compared to when using a standard purified from human donors...... similar, and correlated (r(S) = 0.773, P assay is highly sensitive and suited for analysis...

Evaluation of a Commercial Sandwich Enzyme-Linked Immunosorbent Assay for the Quantification of Beta-Casomorphin 7 in Yogurt Using Solid-Phase Extraction Coupled to Liquid Chromatography-Tandem Mass Spectrometry as the "Gold Standard" Method.

Science.gov (United States)

Nguyen, Duc Doan; Busetti, Francesco; Johnson, Stuart Keith; Solah, Vicky Ann

2018-03-01

This study investigated beta-casomorphin 7 (BCM7) in yogurt by means of LC-tandem MS (MS/MS) and enzyme-linked immunosorbent assay (ELISA) and use LC-MS/MS as the "gold standard" method to evaluate the applicability of a commercial ELISA. The level of BCM7 in milk obtained from ELISA analysis was much lower than that obtained by LC-MS/MS analysis and trended to increase during fermentation and storage of yogurt. Meanwhile, the results obtained from LC-MS/MS showed that BCM7 degraded during stages of yogurt processing, and its degradation may have been caused by X-prolyl dipeptidyl aminopeptidase activity. As a result, the commercial sandwich ELISA kit was not suitable for the quantification of BCM7 in fermented dairy milk.

Rapid validated HPTLC method for estimation of piperine and piperlongumine in root of Piper longum extract and its commercial formulation

Directory of Open Access Journals (Sweden)

Anagha A. Rajopadhye

2012-12-01

Full Text Available Piperine and piperlongumine, alkaloids having diverse biological activities, commonly occur in roots of Piper longum L., Piperaceae, which have high commercial, economical and medicinal value. In present study, rapid, validated HPTLC method has been established for the determination of piperine and piperlongumine in methanolic root extract and its commercial formulation 'Mahasudarshan churna®' using ICH guidelines. The use of Accelerated Solvent Extraction (ASE as an alternative to conventional techniques has been explored. The methanol extracts of root, its formulation and both standard solutions were applied on silica gel F254 HPTLC plates. The plates were developed in Twin chamber using mobile phase toluene: ethyl acetate (6:4, v/v and scanned at 342 and 325 nm (λmax of piperine and piperlongumine, respectively using Camag TLC scanner 3 with CATS 4 software. A linear relationship was obtained between response (peak area and amount of piperine and piperlongumine in the range of 20-100 and 30-150 ng/spot, respectively; the correlation coefficient was 0.9957 and 0.9941 respectively. Sharp, symmetrical and well resolved peaks of piperine and piperlongumine spots resolved at Rf 0.51 and 0.74, respectively from other components of the sample extracts. The HPTLC method showed good linearity, recovery and high precision of both markers. Extraction of plant using ASE and rapid HPTLC method provides a new and powerful approach to estimate piperine and piperlongumine as phytomarkers in the extract as well as its commercial formulations for routine quality control.

The Abbott RealTime High Risk HPV test is a clinically validated human papillomavirus assay for triage in the referral population and use in primary cervical cancer screening in women 30 years and older: a review of validation studies.

Science.gov (United States)

Poljak, Mario; Oštrbenk, Anja

2013-01-01

Human papillomavirus (HPV) testing has become an essential part of current clinical practice in the management of cervical cancer and precancerous lesions. We reviewed the most important validation studies of a next-generation real-time polymerase chain reaction-based assay, the RealTime High Risk HPV test (RealTime)(Abbott Molecular, Des Plaines, IL, USA), for triage in referral population settings and for use in primary cervical cancer screening in women 30 years and older published in peer-reviewed journals from 2009 to 2013. RealTime is designed to detect 14 high-risk HPV genotypes with concurrent distinction of HPV-16 and HPV-18 from 12 other HPV genotypes. The test was launched on the European market in January 2009 and is currently used in many laboratories worldwide for routine detection of HPV. We concisely reviewed validation studies of a next-generation real-time polymerase chain reaction (PCR)-based assay: the Abbott RealTime High Risk HPV test. Eight validation studies of RealTime in referral settings showed its consistently high absolute clinical sensitivity for both CIN2+ (range 88.3-100%) and CIN3+ (range 93.0-100%), as well as comparative clinical sensitivity relative to the currently most widely used HPV test: the Qiagen/Digene Hybrid Capture 2 HPV DNA Test (HC2). Due to the significantly different composition of the referral populations, RealTime absolute clinical specificity for CIN2+ and CIN3+ varied greatly across studies, but was comparable relative to HC2. Four validation studies of RealTime performance in cervical cancer screening settings showed its consistently high absolute clinical sensitivity for both CIN2+ and CIN3+, as well as comparative clinical sensitivity and specificity relative to HC2 and GP5+/6+ PCR. RealTime has been extensively evaluated in the last 4 years. RealTime can be considered clinically validated for triage in referral population settings and for use in primary cervical cancer screening in women 30 years and older.

Detection of 12 respiratory viruses by duplex real time PCR assays in respiratory samples.

Science.gov (United States)

Arvia, Rosaria; Corcioli, Fabiana; Ciccone, Nunziata; Della Malva, Nunzia; Azzi, Alberta

2015-12-01

Different viruses can be responsible for similar clinical manifestations of respiratory infections. Thus, the etiological diagnosis of respiratory viral diseases requires the detection of a large number of viruses. In this study, 6 duplex real-time PCR assays, using EvaGreen intercalating dye, were developed to detect 12 major viruses responsible for respiratory diseases: influenza A and B viruses, enteroviruses (including enterovirus spp, and rhinovirus spp), respiratory syncytial virus, human metapneumovirus, coronaviruses group I (of which CoV 229E and CoV NL63 are part) and II (including CoV OC43 and CoV HKU1), parainfluenza viruses type 1, 2, 3 and 4, human adenoviruses and human bocaviruses. The 2 target viruses of each duplex reaction were distinguishable by the melting temperatures of their amplicons. The 6 duplex real time PCR assays were applied for diagnostic purpose on 202 respiratory samples from 157 patients. One hundred fifty-seven samples were throat swabs and 45 were bronchoalveolar lavages. The results of the duplex PCR assays were confirmed by comparison with a commercial, validated, assay; in addition, the positive results were confirmed by sequencing. The analytical sensitivity of the duplex PCR assays varied from 10(3) copies/ml to 10(4) copies/ml. For parainfluenza virus 2 only it was 10(5) copies/ml. Seventy clinical samples (35%) from 55 patients (30 children and 25 adults) were positive for 1 or more viruses. In adult patients, influenza A virus was the most frequently detected respiratory virus followed by rhinoviruses. In contrast, respiratory syncytial virus was the most common virus in children, followed by enteroviruses, influenza A virus and coronavirus NL63. The small number of samples/patients does not allow us to draw any epidemiological conclusion. Altogether, the results of this study indicate that the 6 duplex PCR assays described in this study are sensitive, specific and cost-effective. Thus, this assay could be

Preliminary Validation and Verification Plan for CAREM Reactor Protection System

International Nuclear Information System (INIS)

Fittipaldi, Ana; Maciel Felix

2000-01-01

The purpose of this paper, is to present a preliminary validation and verification plan for a particular architecture proposed for the CAREM reactor protection system with software modules (computer based system).These software modules can be either own design systems or systems based in commercial modules such as programmable logic controllers (PLC) redundant of last generation.During this study, it was seen that this plan can also be used as a validation and verification plan of commercial products (COTS, commercial off the shelf) and/or smart transmitters.The software life cycle proposed and its features are presented, and also the advantages of the preliminary validation and verification plan

Analytical and clinical performance of the new Fujirebio 25-OH vitamin D assay, a comparison with liquid chromatography-tandem mass spectrometry (LC-MS/MS) and three other automated assays.

Science.gov (United States)

Saleh, Lanja; Mueller, Daniel; von Eckardstein, Arnold

2016-04-01

We evaluated the analytical and clinical performance of the new Lumipulse® G 25-OH vitamin D assay from Fujirebio, and compared it to a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method and three other commercial automated assays. Total 25 hydroxy vitamin D (25(OH)D) levels were measured in 100 selected serum samples from our routine analysis with Fujirebio 25(OH)D assay. The results were compared with those obtained with LC-MS/MS and three other automated 25(OH)D assays (Abbott, Beckman, and Roche). The accuracy of each assay tested was evaluated against a Labquality reference serum panel for 25(OH)D (Ref!25OHD; University of Ghent). Intra- and inter-day imprecision of the Fujirebio 25(OH)D assay was Lumipulse G 25-OH vitamin D assay from Fujirebio demonstrated a good correlation with LC-MS/MS and some immunoassays. The performance of the assay is well-suited for routine 25(OH)D measurement in clinical serum samples. A correction for the observed negative bias vs. LC-MS/MS could be considered.

The validation of waste assay systems during active test at Rokkasho Reprocessing Plant

International Nuclear Information System (INIS)

Tamura, Takayuki; Miura, Yasushi; Iwamoto, Tomonori

2007-01-01

In order to implement accurate material accountancy at Rokkasho Reprocessing Plant (RRP) as a large scale reprocessing plant, it is necessary to introduce accurate measurement systems not only for mainstream material, but also appropriate measurement systems for solid waste materials. In this sense, the generated wastes by the active test operation have been measured with the Non-Destructive Assay Systems, such as Rokkasho Hulls Measurement System (RHMS) and Waste Crate Assay System (WCAS) for accountancy. This paper describes the experience of the NDA operation and the evaluation results for accountancy. (author)

A simple micro-extraction plate assay for automated LC-MS/MS analysis of human serum 25-hydroxyvitamin D levels.

Science.gov (United States)

Geib, Timon; Meier, Florian; Schorr, Pascal; Lammert, Frank; Stokes, Caroline S; Volmer, Dietrich A

2015-01-01

This short application note describes a simple and automated assay for determination of 25-hydroxyvitamin D (25(OH)D) levels in very small volumes of human serum. It utilizes commercial 96-well micro-extraction plates with commercial 25(OH)D isotope calibration and quality control kits. Separation was achieved using a pentafluorophenyl liquid chromatography column followed by multiple reaction monitoring-based quantification on an electrospray triple quadrupole mass spectrometer. Emphasis was placed on providing a simple assay that can be rapidly established in non-specialized laboratories within days, without the need for laborious and time consuming sample preparation steps, advanced calibration or data acquisition routines. The analytical figures of merit obtained from this assay compared well to established assays. To demonstrate the applicability, the assay was applied to analysis of serum samples from patients with chronic liver diseases and compared to results from a routine clinical immunoassay. Copyright © 2015 John Wiley & Sons, Ltd.

Specific and sensitive enzyme-linked immunosorbent assays for analysis of residual allergenic food proteins in commercial bottled wine fined with egg white, milk, and nongrape-derived tannins.

Science.gov (United States)

Rolland, Jennifer M; Apostolou, Effie; de Leon, Maria P; Stockley, Creina S; O'Hehir, Robyn E

2008-01-23

Regulations introduced by the Food Standards Australia New Zealand in December 2002 require all wine and wine product labels in Australia to identify the presence of a processing aid, additive or other ingredient, which is known to be a potential allergen. The objective of this study was to establish sensitive assays to detect and measure allergenic proteins from commonly used processing aids in final bottled wine. Sensitive and specific enzyme-linked immunosorbent assays (ELISA) were developed and established for the proteins casein, ovalbumin, and peanut. Lower limits of detection of these proteins were 8, 1, and 8 ng/mL, respectively. A panel of 153 commercially available bottled Australian wines were tested by these ELISA, and except for two red wines known to contain added whole eggs, residuals of these food allergens were not detected in any wine. These findings are consistent with a lack of residual potentially allergenic egg-, milk-, or nut-derived processing aids in final bottled wine produced in Australia according to good manufacturing practice at a concentration that could cause an adverse reaction in egg, milk, or peanut/tree-nut allergic adult consumers.

Irradiation detection of food by DNA Comet Assay

International Nuclear Information System (INIS)

Khan, A.A.; Delincee, H.

1999-01-01

Microgel electrophoresis of single cells or nuclei (DNA Comet Assay) has been investigated to detect irradiation treatment of more than 50 food commodities e.g. meats, seafood, cereals, pulses, nuts, fruits and vegetables, and spices. The foodstuffs have been exposed to radiation doses covering the range of potential commercial irradiation for inactivation of pathogenic and spoilage micro-organisms, for insect disinfestation and for shelf-life extension. The Comet Assay is based on detection of DNA fragments presumptive to irradiation. For most of the food items investigated, the assay can be applied successfully for irradiation detection by working out different conditions of the assay. However, with some of the foods difficulties arose due to - lack of discrimination between the irradiated and unirradiated food samples due to the presence of the same kinds of comets in both cases and the total absence of the typical intact cells in unirradiated samples. - Sufficient DNA material was not available from some of the foods. - Insufficient lysis of the cell walls in case of some plant foods. In conclusion, the DNA Comet Assay can help to detect the irradiation treatment of several varieties of foods using low-cost equipment in a short time of analysis. (orig.)

Using commercial simulators for determining flash distillation curves for petroleum fractions

OpenAIRE

Eleonora Erdmann; Demetrio Humana; Samuel Franco Domínguez; Lorgio Mercado Fuentes

2010-01-01

This work describes a new method for estimating the equilibrium flash vaporisation (EFV) distillation curve for petro-leum fractions by using commercial simulators. A commercial simulator was used for implementing a stationary mo-del for flash distillation; this model was adjusted by using a distillation curve obtained from standard laboratory ana-lytical assays. Such curve can be one of many types (eg ASTM D86, D1160 or D2887) and involves an experimental procedure simpler than that required...

Quantitative Fissile Assay In Used Fuel Using LSDS System

Science.gov (United States)

Lee, YongDeok; Jeon, Ju Young; Park, Chang-Je

2017-09-01

A quantitative assay of isotopic fissile materials (U235, Pu239, Pu241) was done at Korea Atomic Energy Research Institute (KAERI), using lead slowing down spectrometer (LSDS). The optimum design of LSDS was performed based on economics, easy maintenance and assay effectiveness. LSDS system consists of spectrometer, neutron source, detection and control. LSDS system induces fissile fission and fast neutrons are collected at fission chamber. The detected signal has a direct relation to the mass of existing fissile isotopes. Many current commercial assay technologies have a limitation in direct application on isotopic fissile assay of spent fuel, except chemical analysis. In the designed system, the fissile assay model was setup and the correction factor for self-shield was obtained. The isotopic fissile content assay was performed by changing the content of Pu239. Based on the fuel rod, the isotopic content was consistent with 2% uncertainty for Pu239. By applying the covering (neutron absorber), the effective shielding was obtained and the activation was calculated on the target. From the assay evaluation, LSDS technique is very powerful and direct to analyze the isotopic fissile content. LSDS is applicable for nuclear fuel cycle and spent fuel management for safety and economics. Additionally, an accurate fissile content will contribute to the international transparency and credibility on spent fuel.

Validating analysis methodologies used in burnup credit criticality calculations

International Nuclear Information System (INIS)

Brady, M.C.; Napolitano, D.G.

1992-01-01

The concept of allowing reactivity credit for the depleted (or burned) state of pressurized water reactor fuel in the licensing of spent fuel facilities introduces a new challenge to members of the nuclear criticality community. The primary difference in this analysis approach is the technical ability to calculate spent fuel compositions (or inventories) and to predict their effect on the system multiplication factor. Isotopic prediction codes are used routinely for in-core physics calculations and the prediction of radiation source terms for both thermal and shielding analyses, but represent an innovation for criticality specialists. This paper discusses two methodologies currently being developed to specifically evaluate isotopic composition and reactivity for the burnup credit concept. A comprehensive approach to benchmarking and validating the methods is also presented. This approach involves the analysis of commercial reactor critical data, fuel storage critical experiments, chemical assay isotopic data, and numerical benchmark calculations

Summary Report of Commercial reactor Criticality Data for Three Mile Island Unit 1

International Nuclear Information System (INIS)

Larry B. Wimmer

2001-01-01

The objective of the ''Summary Report of Commercial Reactor Criticality Data for Three Mile Island Unit I'' is to present the CRC data for the TMI-1 reactor. Results from the CRC evaluations will support the development and validation of the neutronics models used for criticality analyses involving commercial spent nuclear fuel. These models and their validation are discussed in the ''Disposal Criticality Analysis Methodology Topical Report'' (YMP 2000)

DTU PMU Laboratory Development - Testing and Validation

OpenAIRE

Garcia-Valle, Rodrigo; Yang, Guang-Ya; Martin, Kenneth E.; Nielsen, Arne Hejde; Østergaard, Jacob

2010-01-01

This is a report of the results of phasor measurement unit (PMU) laboratory development and testing done at the Centre for Electric Technology (CET), Technical University of Denmark (DTU). Analysis of the PMU performance first required the development of tools to convert the DTU PMU data into IEEE standard, and the validation is done for the DTU-PMU via a validated commercial PMU. The commercial PMU has been tested from the authors' previous efforts, where the response can be expected to foll...

Accuracy of molecular diagnostics in pemphigus and bullous pemphigoid: comparison of commercial and modified mosaic indirect immunofluorescence tests as well as enzyme-linked immunosorbent assays.

Science.gov (United States)

Gornowicz-Porowska, Justyna; Seraszek-Jaros, Agnieszka; Bowszyc-Dmochowska, Monika; Kaczmarek, Elżbieta; Pietkiewicz, Paweł; Bartkiewicz, Paweł; Dmochowski, Marian

2017-02-01

Pemphigus and bullous pemphigoid (BP) are identified by autoantibodies (abs) against desmoglein 1, 3 (DSG1/3) and BP180/BP230, respectively. A novel mosaic to indirect immunofluorescence (IIF) using purified BP180 recombinant proteins spotted on slide and transfected cells expressing BP230, DSG1, DSG3 is available. The commercial (IgG detection) and modified (IgG4 detection) mosaic for indirect immunofluorescence (IIFc - IIF commercial, IIFm - IIF modified) and IgG ELISAs were evaluated in pemphigus and bullous pemphigoid (BP) molecular diagnostics. To compare diagnostic accuracy of commercial (IgG detection) and modified (IgG4 detection) mosaic IIF assay and to examine the diagnostic value of ELISAs in relation to mosaic IIF in routine laboratory diagnostics of pemphigus and BP. Sera from 37 BP and 19 pemphigus patients were studied. Associations between tests were assessed using Fisher's exact test. There are associations between the positive/negative samples detected by IIFc with desmoglein1 (DSG1)/desmoglein3 (DSG3)/BP230 transfected cells and ELISAs and no association between anti-BP180 IgG detection by IIFc and ELISA. IIFm with DSG1 and DSG3 showed both 100% sensitivity and 100% and 78% specificity, respectively, and 100% and 83% positive predictive value in relation to IIFc. IIFm with BP230 had 87% specificity, 55% sensitivity, whereas IIFm with BP180 had a 100% sensitivity and 13% specificity in relation to IIFc. The IIFc with DSG1/DSG3/BP230 transfected cells, excluding BP180 spots, is an alternative method to ELISA in pemphigus/BP diagnostics. IgG4 antibodies, both pathogenically and diagnostically important, are inconsistently detectable with IIFm.

DBS-LC-MS/MS assay for caffeine: validation and neonatal application.

Science.gov (United States)

Bruschettini, Matteo; Barco, Sebastiano; Romantsik, Olga; Risso, Francesco; Gennai, Iulian; Chinea, Benito; Ramenghi, Luca A; Tripodi, Gino; Cangemi, Giuliana

2016-09-01

DBS might be an appropriate microsampling technique for therapeutic drug monitoring of caffeine in infants. Nevertheless, its application presents several issues that still limit its use. This paper describes a validated DBS-LC-MS/MS method for caffeine. The results of the method validation showed an hematocrit dependence. In the analysis of 96 paired plasma and DBS clinical samples, caffeine levels measured in DBS were statistically significantly lower than in plasma but the observed differences were independent from hematocrit. These results clearly showed the need for extensive validation with real-life samples for DBS-based methods. DBS-LC-MS/MS can be considered to be a good alternative to traditional methods for therapeutic drug monitoring or PK studies in preterm infants.

Evaluation of the Thermo Scientific SureTect Salmonella species assay. AOAC Performance Tested Method 051303.

Science.gov (United States)

Cloke, Jonathan; Clark, Dorn; Radcliff, Roy; Leon-Velarde, Carlos; Larson, Nathan; Dave, Keron; Evans, Katharine; Crabtree, David; Hughes, Annette; Simpson, Helen; Holopainen, Jani; Wickstrand, Nina; Kauppinen, Mikko

2014-01-01

The Thermo Scientific SureTect Salmonella species Assay is a new real-time PCR assay for the detection of Salmonellae in food and environmental samples. This validation study was conducted using the AOAC Research Institute (RI) Performance Tested Methods program to validate the SureTect Salmonella species Assay in comparison to the reference method detailed in International Organization for Standardization 6579:2002 in a variety of food matrixes, namely, raw ground beef, raw chicken breast, raw ground pork, fresh bagged lettuce, pork frankfurters, nonfat dried milk powder, cooked peeled shrimp, pasteurized liquid whole egg, ready-to-eat meal containing beef, and stainless steel surface samples. With the exception of liquid whole egg and fresh bagged lettuce, which were tested in-house, all matrixes were tested by Marshfield Food Safety, Marshfield, WI, on behalf of Thermo Fisher Scientific. In addition, three matrixes (pork frankfurters, lettuce, and stainless steel surface samples) were analyzed independently as part of the AOAC-RI-controlled laboratory study by the University of Guelph, Canada. No significant difference by probability of detection or McNemars Chi-squared statistical analysis was found between the candidate or reference methods for any of the food matrixes or environmental surface samples tested during the validation study. Inclusivity and exclusivity testing was conducted with 117 and 36 isolates, respectively, which demonstrated that the SureTect Salmonella species Assay was able to detect all the major groups of Salmonella enterica subspecies enterica (e.g., Typhimurium) and the less common subspecies of S. enterica (e.g., arizoniae) and the rarely encountered S. bongori. None of the exclusivity isolates analyzed were detected by the SureTect Salmonella species Assay. Ruggedness testing was conducted to evaluate the performance of the assay with specific method deviations outside of the recommended parameters open to variation (enrichment time

Validity of Thermal Ramping Assays Used to Assess Thermal Tolerance in Arthropods

DEFF Research Database (Denmark)

Overgaard, Johannes; Kristensen, Torsten Nygård; Sørensen, Jesper Givskov

2012-01-01

are useful assays for small insects because they incorporate an ecologically relevant gradual temperature change. However, recent model-based papers have suggested that estimates of thermal resistance may be strongly confounded by simultaneous starvation and dehydration stress. In the present study we...... empirically test these model predictions using two sets of independent experiments. We clearly demonstrate that results from ramping assays of small insects (Drosophila melanogaster) are not compromised by starvation- or dehydration-stress. Firstly we show that the mild disturbance of water and energy balance...... of D. melanogaster experienced during the ramping tests does not confound heat tolerance estimates. Secondly we show that flies pre-exposed to starvation and dehydration have ‘‘normal’’ heat tolerance and that resistance to heat stress is independent of the energetic and water status of the flies...

Development, optimization, and single laboratory validation of an event-specific real-time PCR method for the detection and quantification of Golden Rice 2 using a novel taxon-specific assay.

Science.gov (United States)

Jacchia, Sara; Nardini, Elena; Savini, Christian; Petrillo, Mauro; Angers-Loustau, Alexandre; Shim, Jung-Hyun; Trijatmiko, Kurniawan; Kreysa, Joachim; Mazzara, Marco

2015-02-18

In this study, we developed, optimized, and in-house validated a real-time PCR method for the event-specific detection and quantification of Golden Rice 2, a genetically modified rice with provitamin A in the grain. We optimized and evaluated the performance of the taxon (targeting rice Phospholipase D α2 gene)- and event (targeting the 3' insert-to-plant DNA junction)-specific assays that compose the method as independent modules, using haploid genome equivalents as unit of measurement. We verified the specificity of the two real-time PCR assays and determined their dynamic range, limit of quantification, limit of detection, and robustness. We also confirmed that the taxon-specific DNA sequence is present in single copy in the rice genome and verified its stability of amplification across 132 rice varieties. A relative quantification experiment evidenced the correct performance of the two assays when used in combination.

Human neuron-astrocyte 3D co-culture-based assay for evaluation of neuroprotective compounds.

Science.gov (United States)

Terrasso, Ana Paula; Silva, Ana Carina; Filipe, Augusto; Pedroso, Pedro; Ferreira, Ana Lúcia; Alves, Paula Marques; Brito, Catarina

Central nervous system drug development has registered high attrition rates, mainly due to the lack of efficacy of drug candidates, highlighting the low reliability of the models used in early-stage drug development and the need for new in vitro human cell-based models and assays to accurately identify and validate drug candidates. 3D human cell models can include different tissue cell types and represent the spatiotemporal context of the original tissue (co-cultures), allowing the establishment of biologically-relevant cell-cell and cell-extracellular matrix interactions. Nevertheless, exploitation of these 3D models for neuroprotection assessment has been limited due to the lack of data to validate such 3D co-culture approaches. In this work we combined a 3D human neuron-astrocyte co-culture with a cell viability endpoint for the implementation of a novel in vitro neuroprotection assay, over an oxidative insult. Neuroprotection assay robustness and specificity, and the applicability of Presto Blue, MTT and CytoTox-Glo viability assays to the 3D co-culture were evaluated. Presto Blue was the adequate endpoint as it is non-destructive and is a simpler and reliable assay. Semi-automation of the cell viability endpoint was performed, indicating that the assay setup is amenable to be transferred to automated screening platforms. Finally, the neuroprotection assay setup was applied to a series of 36 test compounds and several candidates with higher neuroprotective effect than the positive control, Idebenone, were identified. The robustness and simplicity of the implemented neuroprotection assay with the cell viability endpoint enables the use of more complex and reliable 3D in vitro cell models to identify and validate drug candidates. Copyright © 2016 Elsevier Inc. All rights reserved.

European Perspectives on International Commercial Arbitration

DEFF Research Database (Denmark)

Hauberg Wilhelmsen, Louise

2014-01-01

of a uniform rule on the law applicable to the existence and validity of an arbitration agreement. This article examines these issues in order to find out whether they are only European or also inherent in the international regulation of international commercial arbitration. The article examines to which...

Independency of Fe ions in hemoglobin on immunomagnetic reduction assay

International Nuclear Information System (INIS)

Yang, S.Y.; Lan, C.B.; Chen, C.H.; Horng, H.E.; Hong, Chin-Yih; Yang, H.C.; Lai, Y.K.; Lin, Y.H.; Teng, K.S.

2009-01-01

Immunomagnetic reduction (IMR), which involves measuring the reduction in the ac magnetic susceptibility of magnetic reagents, is due to the association between bio-functionalized magnetic nanoparticles and target bio-molecules. This has been demonstrated for assaying proteins in solutions free of Fe ions, such as serum. In this work, the validity of IMR assay for samples rich in Fe ions like hemoglobin (Hb) is investigated. According to the results, there is no magnetic signal contributed by Fe-ion-rich Hb. Furthermore, the results show a high sensitivity in assaying hemoglobin A1c (HbA1c) by using IMR.

Independency of Fe ions in hemoglobin on immunomagnetic reduction assay

Energy Technology Data Exchange (ETDEWEB)

Yang, S.Y. [MagQu Co. Ltd., Sindian City, Taipei County 231, Taiwan (China); Institute of Electro-optical Science and Technology, National Taiwan Normal University, Taipei 116, Taiwan (China); Lan, C.B.; Chen, C.H. [Institute of Electro-optical Science and Technology, National Taiwan Normal University, Taipei 116, Taiwan (China); Horng, H.E. [Institute of Electro-optical Science and Technology, National Taiwan Normal University, Taipei 116, Taiwan (China)], E-mail: phyfv001@scc.ntnu.edu.tw; Hong, Chin-Yih [Department of Mechanical Engineering, Nan-Kai University of Technology, Nantau County, Taiwan (China)], E-mail: cyhong@nkut.edu.tw; Yang, H.C. [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China)], E-mail: hcyang@phys.ntu.edu.tw; Lai, Y.K. [College of Life Sciences, National Tsing Hua University, Hsinchu City 300, Taiwan (China); Department of Bioresources, Da-Yeh University, Changhua 515, Taiwan (China); Lin, Y.H.; Teng, K.S. [Apex Biotechnology Co. Ltd., Hsinchu City 300, Taiwan (China)

2009-10-15

Immunomagnetic reduction (IMR), which involves measuring the reduction in the ac magnetic susceptibility of magnetic reagents, is due to the association between bio-functionalized magnetic nanoparticles and target bio-molecules. This has been demonstrated for assaying proteins in solutions free of Fe ions, such as serum. In this work, the validity of IMR assay for samples rich in Fe ions like hemoglobin (Hb) is investigated. According to the results, there is no magnetic signal contributed by Fe-ion-rich Hb. Furthermore, the results show a high sensitivity in assaying hemoglobin A1c (HbA1c) by using IMR.

Development and validation of an LC-MS/MS method for quantification of cyclic guanosine 3',5'-monophosphate (cGMP) in clinical applications: a comparison with a EIA method.

Science.gov (United States)

Zhang, Yanhua; Dufield, Dawn; Klover, Jon; Li, Wenlin; Szekely-Klepser, Gabriella; Lepsy, Christopher; Sadagopan, Nalini

2009-02-15

An LC-MS/MS method was developed and validated to quantify endogenous cyclic guanosine 3',5'-monophosphate (cGMP) in human plasma. The LC-MS/MS and competitive enzyme immunoassay (EIA) assays were compared. cGMP concentrations of 20 human plasma samples were measured by both methods. For the MS-based assay, plasma samples were subjected to a simple protein precipitation procedure by acetonitrile prior to analysis by electrospray ionization LC-MS/MS. De-protonated analytes generated in negative ionization mode were monitored through multiple reaction monitoring (MRM). A stable isotope-labeled internal standard, (13)C(10),(15)N(5)-cGMP, which was biosynthesized in-house, was used in the LC-MS/MS method. The competitive EIA was validated using a commercially available cGMP fluorescence assay kit. The intra-assay accuracy and precision for MS-based assay for cGMP were 6-10.1% CV and -3.6% to 7.3% relative error (RE), respectively, while inter-assay precision and accuracy were 5.6-8.1% CV and -2.1% to 6.3% RE, respectively. The intra-assay accuracy and precision for EIA were 17.9-27.1% CV and -4.9% to 24.5% RE, respectively, while inter-assay precision and accuracy were 15.1-39.5% CV and -30.8% to 4.37% RE, respectively. Near the lower limits of detection, there was little correlation between the cGMP concentration values in human plasma generated by these two methods (R(2)=0.197, P=0.05). Overall, the MS-based assay offered better selectivity, recovery, precision and accuracy over a linear range of 0.5-20ng/mL. The LC-MS/MS method provides an effective tool for the quantitation of cGMP to support clinical mechanistic studies of curative pharmaceuticals.

Multiplexing a high-throughput liability assay to leverage efficiencies.

Science.gov (United States)

Herbst, John; Anthony, Monique; Stewart, Jeremy; Connors, David; Chen, Taosheng; Banks, Martyn; Petrillo, Edward W; Agler, Michele

2009-06-01

In order to identify potential cytochrome P-450 3A4 (drug-metabolizing enzyme) inducers at an early stage of the drug discovery process, a cell-based transactivation high-throughput luciferase reporter assay for the human pregnane X receptor (PXR) in HepG2 cells has been implemented and multiplexed with a viability end point for data interpretation, as part of a Lead Profiling portfolio of assays. As a routine part of Lead Profiling operations, assays are periodically evaluated for utility as well as for potential improvements in technology or process. We used a recent evaluation of our PXR-transactivation assay as a model for the application of Lean Thinking-based process analysis to lab-bench assay optimization and automation. This resulted in the development of a 384-well multiplexed homogeneous assay simultaneously detecting PXR transactivation and HepG2 cell cytotoxicity. In order to multiplex fluorescent and luminescent read-outs, modifications to each assay were necessary, which included optimization of multiple assay parameters such as cell density, plate type, and reagent concentrations. Subsequently, a set of compounds including known cytotoxic compounds and PXR inducers were used to validate the multiplexed assay. Results from the multiplexed assay correlate well with those from the singleplexed assay formats measuring PXR transactivation and viability separately. Implementation of the multiplexed assay for routine compound profiling provides improved data quality, sample conservation, cost savings, and resource efficiencies.

Rapid colorimetric assay for gentamicin injection.

Science.gov (United States)

Tarbutton, P

1987-01-01

A rapid colorimetric method for determining gentamicin concentration in commercial preparations of gentamicin sulfate injection was developed. Methods currently available for measuring gentamicin concentration via its colored complex with cupric ions in alkaline solution were modified to reduce the time required for a single analysis. The alkaline copper tartrate (ACT) reagent solution was prepared such that each milliliter contained 100 mumol cupric sulfate, 210 mumol potassium sodium tartrate, and 1.25 mmol sodium hydroxide. The assay involves mixing 0.3 mL gentamicin sulfate injection 40 mg/mL (of gentamicin), 1.0 mL ACT reagent, and 0.7 mL water; the absorbance of the resulting solution at 560 nm was used to calculate the gentamicin concentration in the sample. For injections containing 10 mg/mL of gentamicin, the amount of the injection was increased to 0.5 mL and water decreased to 0.5 mL. The concentration of gentamicin in samples representing 11 lots of gentamicin sulfate injection 40 mg/mL and 8 lots of gentamicin sulfate injection 10 mg/mL was determined. The specificity, reproducibility, and accuracy of the assay were assessed. The colored complex was stable for at least two hours. Gentamicin concentration ranged from 93.7 to 108% and from 95 to 109% of the stated label value of the 40 mg/mL and the 10 mg/mL injections, respectively. No components of the preservative system present in the injections interfered with the assay. Since other aminoglycosides produced a colored complex, the assay is not specific for gentamicin. The assay was accurate and reproducible over the range of 4-20 mg of gentamicin. This rapid and accurate assay can be easily applied in the hospital pharmacy setting.

Radioimmunoassay of human homologous prolactin in serum with commercially available reagents. [/sup 125/I tracer technique

Energy Technology Data Exchange (ETDEWEB)

Kao, P.C.; Jiang, N.S.; Abboud, C.F.

1977-09-01

A clinically useful and reproducible radioimmunoassay for human homologous prolactin, established with commercially available reagents, was studied and validated. We present detailed conditions for iodination and purification of labeled prolactin and the optimal conditions for the assay. By the method, we found values (..mu..g/liter) as follows for serum prolactin: normal men, 8.9 +- 5.2 (mean +- SD); normal women, 11.8 +- 5.5; normal women taking contraceptive pills, 9.2 +- 5.0; pregnant women in the third trimester, 188 +- 69.5; patients with various diseases other than of the hypothalamic-pituitary axis, 9.3 +- 6.3; in some patients with amenorrhea and galactorrhea of diverse origin, 78.2 +- 87.4; and in some patients with surgically proven pituitary tumor, 1414 +- 1980. Results under provocative testing are also presented for a patient with normal hypothalamic-pituitary function.

Recommendations for safety testing with the in vivo comet assay.

Science.gov (United States)

Vasquez, Marie Z

2012-08-30

While the in vivo comet assay increases its role in regulatory safety testing, deliberations about the interpretation of comet data continue. Concerns can arise regarding comet assay publications with limited data from non-blind testing of positive control compounds and using protocols (e.g. dose concentrations, sample times, and tissues) known to give an expected effect. There may be a tendency towards bias when the validation or interpretation of comet assay data is based on results generated by widely accepted but non-validated assays. The greatest advantages of the comet assay are its sensitivity and its ability to detect genotoxicity in tissues and at sample times that could not previously be evaluated. Guidelines for its use and interpretation in safety testing should take these factors into account. Guidelines should be derived from objective review of data generated by blind testing of unknown compounds dosed at non-toxic concentrations and evaluated in a true safety-testing environment, where the experimental design and conclusions must be defensible. However, positive in vivo comet findings with such compounds are rarely submitted to regulatory agencies and this data is typically unavailable for publication due to its proprietary nature. To enhance the development of guidelines for safety testing with the comet assay, and with the permission of several sponsors, this paper presents and discusses relevant data from multiple GLP comet studies conducted blind, with unknown pharmaceuticals and consumer products. Based on these data and the lessons we have learned through the course of conducting these studies, I suggest significant adjustments to the current conventions, and I provide recommendations for interpreting in vivo comet assay results in situations where risk must be evaluated in the absence of carcinogenicity or clinical data. Copyright © 2012 Elsevier B.V. All rights reserved.

Molecular Methods for Typing of Streptococcus agalactiae with Special Emphasis on the Development and Validation of a Multi-Locus Variable Number of Tandem Repeats Assay (MLVA)

OpenAIRE

Radtke, Andreas

2012-01-01

Molekylære metoder for typing av Streptococcus agalactiae med særlig vektlegging av utvikling og validering av et multi-locus variable number of tandem repeats assay (MLVA) Sammendraget: Streptococcus agalactiae eller gruppe B streptokokker (GBS) forårsaker livsfarlige infeksjoner hos nyfødte, gravide eller voksne med kroniske sykdommer. Den forårsaker også jurbetennelse i storfe. Typing av GBS gir innblikk i bakteriens epidemiologi og dens fylogenetiske slektskap. Ulike deler av bakterie...

Characterization of blood lipoproteins and validation of cholesterol and triacylglycerol assays for free-ranging polar bears (Ursus maritimus).

Science.gov (United States)

Whiteman, John P; Frank, Nicholas; Greller, Katie A; Harlow, Henry J; Ben-David, Merav

2013-05-01

Blood triacylglycerol (TG) and lipoproteins are important variables for evaluating nutritional status of wildlife, but measurements are often expensive and difficult. Performance of a small, portable blood analyzer intended for human medical diagnostics was evaluated in measuring these variables in plasma and serum from free-ranging polar bears (Ursus maritimus), which are experiencing nutritional stress related to sea ice loss. The analyzer accurately tracked changes in concentration of total cholesterol (Ctotal), cholesterol associated with high-density lipoprotein (CHDL), and TG during a validation protocol of diluting samples and spiking them with exogenous cholesterol and glycerol. Values of Ctotal and TG agreed well with values obtained by other methods (ultracentrifugation followed by colorimetric assays); agreement was variable for values of cholesterol associated with specific lipoproteins. Similar to a study of captive polar bears, ultracentrifugation methods revealed greater TG in very low-density lipoproteins than in low-density lipoprotein, which is unusual and merits additional study.

CellAnimation: an open source MATLAB framework for microscopy assays.

Science.gov (United States)

Georgescu, Walter; Wikswo, John P; Quaranta, Vito

2012-01-01

Advances in microscopy technology have led to the creation of high-throughput microscopes that are capable of generating several hundred gigabytes of images in a few days. Analyzing such wealth of data manually is nearly impossible and requires an automated approach. There are at present a number of open-source and commercial software packages that allow the user to apply algorithms of different degrees of sophistication to the images and extract desired metrics. However, the types of metrics that can be extracted are severely limited by the specific image processing algorithms that the application implements, and by the expertise of the user. In most commercial software, code unavailability prevents implementation by the end user of newly developed algorithms better suited for a particular type of imaging assay. While it is possible to implement new algorithms in open-source software, rewiring an image processing application requires a high degree of expertise. To obviate these limitations, we have developed an open-source high-throughput application that allows implementation of different biological assays such as cell tracking or ancestry recording, through the use of small, relatively simple image processing modules connected into sophisticated imaging pipelines. By connecting modules, non-expert users can apply the particular combination of well-established and novel algorithms developed by us and others that are best suited for each individual assay type. In addition, our data exploration and visualization modules make it easy to discover or select specific cell phenotypes from a heterogeneous population. CellAnimation is distributed under the Creative Commons Attribution-NonCommercial 3.0 Unported license (http://creativecommons.org/licenses/by-nc/3.0/). CellAnimationsource code and documentation may be downloaded from www.vanderbilt.edu/viibre/software/documents/CellAnimation.zip. Sample data are available at www

Validation and application of a high-performance liquid chromatography--tandem mass spectrometry assay for mosapride in human plasma.

Science.gov (United States)

Ramakrishna, N V S; Vishwottam, K N; Manoj, S; Koteshwara, M; Chidambara, J; Varma, D P

2005-09-01

A simple, rapid, sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of mosapride (I), a novel and potent gastroprokinetic agent that enhances the upper gastrointestinal motility by stimulating 5-HT(4) receptor. The analyte and internal standard, tamsulosin (II), were extracted by liquid-liquid extraction with diethyl ether-dichloromethane (70:30, v/v) using a Glas-Col Multi-Pulse Vortexer. The chromatographic separation was performed on a reversed-phase Waters symmetry C(18) column with a mobile phase of 0.03% formic acid-acetonitrile (10:90, v/v). The protonated analyte was quantitated in positive ionization by multiple reaction monitoring with a mass spectrometer. The mass transitions m/z 422.3 -->198.3 and m/z 409.1 -->228.1 were used to measure I and II, respectively. The assay exhibited a linear dynamic range of 0.5-100.0 ng/mL for mosapride in human plasma. The lower limit of quantitation was 500 pg/mL with a relative standard deviation of less than 15%. Acceptable precision and accuracy were obtained for concentrations over the standard curve ranges. A run time of 2.0 min for each sample made it possible to analyze a throughput of more than 400 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies. Copyright (c) 2005 John Wiley & Sons, Ltd.

Simplified PCR protocols for INNO-LiPA HBV Genotyping and INNO-LiPA HBV PreCore assays

NARCIS (Netherlands)

Qutub, Mohammed O.; Germer, Jeffrey J.; Rebers, Sjoerd P. H.; Mandrekar, Jayawant N.; Beld, Marcel G. H. M.; Yao, Joseph D. C.

2006-01-01

INNO-LiPA HBV Genotyping (LiPA HBV GT) and INNO-LiPA HBV PreCore (LiPA HBV PC) are commercially available assays for hepatitis B virus (HBV) characterization. These assays are labor-intensive and may be prone to exogenous DNA contamination due to their use of nested PCR amplification procedures and

A real-time PCR assay for detection and quantification of Verticillium dahliae in spinach seed.

Science.gov (United States)

Duressa, Dechassa; Rauscher, Gilda; Koike, Steven T; Mou, Beiquan; Hayes, Ryan J; Maruthachalam, Karunakaran; Subbarao, Krishna V; Klosterman, Steven J

2012-04-01

Verticillium dahliae is a soilborne fungus that causes Verticillium wilt on multiple crops in central coastal California. Although spinach crops grown in this region for fresh and processing commercial production do not display Verticillium wilt symptoms, spinach seeds produced in the United States or Europe are commonly infected with V. dahliae. Planting of the infected seed increases the soil inoculum density and may introduce exotic strains that contribute to Verticillium wilt epidemics on lettuce and other crops grown in rotation with spinach. A sensitive, rapid, and reliable method for quantification of V. dahliae in spinach seed may help identify highly infected lots, curtail their planting, and minimize the spread of exotic strains via spinach seed. In this study, a quantitative real-time polymerase chain reaction (qPCR) assay was optimized and employed for detection and quantification of V. dahliae in spinach germplasm and 15 commercial spinach seed lots. The assay used a previously reported V. dahliae-specific primer pair (VertBt-F and VertBt-R) and an analytical mill for grinding tough spinach seed for DNA extraction. The assay enabled reliable quantification of V. dahliae in spinach seed, with a sensitivity limit of ≈1 infected seed per 100 (1.3% infection in a seed lot). The quantification was highly reproducible between replicate samples of a seed lot and in different real-time PCR instruments. When tested on commercial seed lots, a pathogen DNA content corresponding to a quantification cycle value of ≥31 corresponded with a percent seed infection of ≤1.3%. The assay is useful in qualitatively assessing seed lots for V. dahliae infection levels, and the results of the assay can be helpful to guide decisions on whether to apply seed treatments.

Peptide Binding to HLA Class I Molecules: Homogenous, High-Throughput Screening, and Affinity Assays

DEFF Research Database (Denmark)

Harndahl, Mikkel; Justesen, Sune Frederik Lamdahl; Lamberth, Kasper

2009-01-01

, better signal-to-background ratios, and a higher capacity. They also describe an efficient approach to screen peptides for binding to HLA molecules. For the occasional user, this will serve as a robust, simple peptide-HLA binding assay. For the more dedicated user, it can easily be performed in a high-throughput...... the luminescent oxygen channeling immunoassay technology (abbreviated LOCI and commercialized as AlphaScreen (TM)). Compared with an enzyme-linked immunosorbent assay-based peptide-HLA class I binding assay, the LOCI assay yields virtually identical affinity measurements, although having a broader dynamic range...... screening mode using standard liquid handling robotics and 384-well plates. We have successfully applied this assay to more than 60 different HLA molecules, leading to more than 2 million measurements. (Journal of Biomolecular Screening 2009: 173-180)...

Standard assays do not predict the efficiency of commercial cellulase preparations towards plant materials

NARCIS (Netherlands)

Kabel, M.A.; Maarel, van der M.J.E.C.; Klip, G.; Voragen, A.G.J.; Schols, H.A.

2006-01-01

Commercial cellulase preparations are potentially effective for processing biomass feedstocks in order to obtain bioethanol. In plant cell walls, cellulose fibrils occur in close association with xylans (monocotyls) or xyloglucans (dicotyls). The enzymatic conversion of cellulose/xylans is a complex

Standard Assays Do Not Predict the Efficiency of Commercial Cellulase Preparations Towards Plant Materials

NARCIS (Netherlands)

Kabel, Mirjam A.; Maarel, Marc J.E.C. van der; Klip, Gert; Voragen, Alphons G.J.; Schols, Henk A.

2006-01-01

Commercial cellulase preparations are potentially effective for processing biomass feedstocks in order to obtain bioethanol. In plant cell walls, cellulose fibrils occur in close association with xylans (monocotyls) or xyloglucans (dicotyls). The enzymatic conversion of cellulose/xylans is a complex

Analytical validation of the Roche 25-OH Vitamin D Total assay

DEFF Research Database (Denmark)

Knudsen, Cindy Soendersoe; Nexo, Ebba; Højskov, Carsten Schriver

2012-01-01

) showed Vitamin D Total nmol/L=1.07×(LC-MS/MS) nmol/L+4.7 nmol/L, whereas comparison of 25OHD2 using 23 patient samples showed Vitamin D Total nmol/L=0.55×(LC-MS/MS) nmol/L–2.38 nmol/L (Demings regression). Conclusions: The Roche Vitamin D Total assay is judged suitable for measurement of 25OHD in serum...

Quantification of imatinib in human serum: validation of a high-performance liquid chromatography-mass spectrometry method for therapeutic drug monitoring and pharmacokinetic assays.

Science.gov (United States)

Rezende, Vinicius Marcondes; Rivellis, Ariane; Novaes, Mafalda Megumi Yoshinaga; de Alencar Fisher Chamone, Dalton; Bendit, Israel

2013-01-01

Imatinib mesylate has been a breakthrough treatment for chronic myeloid leukemia. It has become the ideal tyrosine kinase inhibitor and the standard treatment for chronic-phase leukemia. Striking results have recently been reported, but intolerance to imatinib and noncompliance with treatment remain to be solved. Molecular monitoring by quantitative real-time polymerase chain reaction is the gold standard for monitoring patients, and imatinib blood levels have also become an important tool for monitoring. A fast and cheap method was developed and validated using high-performance liquid chromatography-mass spectrometry for quantification of imatinib in human serum and tamsulosin as the internal standard. Remarkable advantages of the method includes use of serum instead of plasma, less time spent on processing and analysis, simpler procedures, and requiring reduced amounts of biological material, solvents, and reagents. Stability of the analyte was also studied. This research also intended to drive the validation scheme in clinical centers. The method was validated according to the requirements of the US Food and Drug Administration and Brazilian National Health Surveillance Agency within the range of 0.500-10.0 μg/mL with a limit of detection of 0.155 μg/mL. Stability data for the analyte are also presented. Given that the validated method has proved to be linear, accurate, precise, and robust, it is suitable for pharmacokinetic assays, such as bioavailability and bioequivalence, and is being successfully applied in routine therapeutic drug monitoring in the hospital service.

Accuracy of molecular diagnostics in pemphigus and bullous pemphigoid: comparison of commercial and modified mosaic indirect immunofluorescence tests as well as enzyme-linked immunosorbent assays

Directory of Open Access Journals (Sweden)

Justyna Gornowicz-Porowska

2017-02-01

Full Text Available Introduction : Pemphigus and bullous pemphigoid (BP are identified by autoantibodies (abs against desmoglein 1, 3 (DSG1/3 and BP180/BP230, respectively. A novel mosaic to indirect immunofluorescence (IIF using purified BP180 recombinant proteins spotted on slide and transfected cells expressing BP230, DSG1, DSG3 is available. The commercial (IgG detection and modified (IgG4 detection mosaic for indirect immunofluorescence (IIFc – IIF commercial, IIFm – IIF modified and IgG ELISAs were evaluated in pemphigus and bullous pemphigoid (BP molecular diagnostics. Aim : To compare diagnostic accuracy of commercial (IgG detection and modified (IgG4 detection mosaic IIF assay and to examine the diagnostic value of ELISAs in relation to mosaic IIF in routine laboratory diagnostics of pemphigus and BP. Material and methods : Sera from 37 BP and 19 pemphigus patients were studied. Associations between tests were assessed using Fisher’s exact test. Results: There are associations between the positive/negative samples detected by IIFc with desmoglein1 (DSG1/desmoglein3 (DSG3/BP230 transfected cells and ELISAs and no association between anti-BP180 IgG detection by IIFc and ELISA. IIFm with DSG1 and DSG3 showed both 100% sensitivity and 100% and 78% specificity, respectively, and 100% and 83% positive predictive value in relation to IIFc. IIFm with BP230 had 87% specificity, 55% sensitivity, whereas IIFm with BP180 had a 100% sensitivity and 13% specificity in relation to IIFc. Conclusions : The IIFc with DSG1/DSG3/BP230 transfected cells, excluding BP180 spots, is an alternative method to ELISA in pemphigus/BP diagnostics. IgG4 antibodies, both pathogenically and diagnostically important, are inconsistently detectable with IIFm.

An immunoenzymatic assay for the diagnosis of hepatitis A utilising immunoglobulin Y

Directory of Open Access Journals (Sweden)

Alexandre dos Santos da Silva

2012-11-01

Full Text Available The detection of anti-hepatitis A virus (HAV antibody levels by diagnostic kits in the convalescent period of disease generally use immunoglobulin G (IgG, which is expensive. An alternative to IgG is immunoglobulin Y (IgY, an immunoglobulin antibody encountered in birds and reptiles. The aim of this study was to develop a competitive immunoenzymatic assay to measure total anti-HAV antibody levels using anti-HAV IgY as the capture and conjugated immunoglobulins. For this purpose, anti-HAV IgY was conjugated to horseradish peroxidase (HRP and the optimal dilution of HRP-conjugated antibodies was evaluated to establish the competitive immuneenzymatic assay. The results obtained from our "in-house" assay were plotted on a receiver operator curve, which showed a sensitivity of 95% and a specificity of 98.8%, demonstrating that a competitive anti-HAV IgY immunoenzymatic assay developed "in house" could be used as an alternative to commercial assays that utilise IgG.

A Quantitative Fluorescence-Based Lipase Assay

Directory of Open Access Journals (Sweden)

Giovanna Lomolino

2012-01-01

Full Text Available An easy and fast gel diffusion assay for detecting and monitoring lipase activity by quantification of fluorescein is described. By measuring the intensity of fluorescein, it is possible to obtain a calibration curve with a regression coefficient better than by using the radius of fluorescent haloes. Through the quantification of fluorescence intensity of fluorescein released after the hydrolysis of a fluorescent ester, fluorescein dibutyrate, used as substrate in agar plates, commercial and skimmed milk lipase activity were studied. Moreover, with this method, lipase activity can be monitored in reaction medium that contains compounds which are affected by turbidity or cause measurement interference for UV-spectrophotometer and fluorimeter. In this experiment, boiled skimmed milk was dispersed in the agar gel with fluorescein dibutyrate, and it was used as a reaction medium to mimic natural conditions. The development of such an assay has a potential for applications in industries ranging from pharmaceuticals to food production and monitoring.

Evaluation of the specificity of antigen assays for plasminogen activator inhibitor 1 : Comparison of two new commercial kits

NARCIS (Netherlands)

Huisman, L.G.M.; Meijer, P.; Griensven, J. van; Kluft, C.

1992-01-01

t-PA depleted citrated plasma was used to prepare standards of different molecular forms of plasminogen activator inhibitor 1 (PAI-1). These standards were used to evaluate the specificity of two new PAI-1 antigen assays: the TintElize PAI-1 antigen assay (cat. no. 210221) and the Innotest PAI-1.

MCNP efficiency calculations of INEEL passive active neutron assay system for simulated TRU waste assays

International Nuclear Information System (INIS)

Yoon, W.Y.; Meachum, T.R.; Blackwood, L.G.; Harker, Y.D.

2000-01-01

The Idaho National Engineering and Environmental Laboratory Stored Waste Examination Pilot Plant (SWEPP) passive active neutron (PAN) radioassay system is used to certify transuranic (TRU) waste drums in terms of quantifying plutonium and other TRU element activities. Depending on the waste form involved, significant systematic and random errors need quantification in addition to the counting statistics. To determine the total uncertainty of the radioassay results, a statistical sampling and verification approach has been developed. In this approach, the total performance of the PAN nondestructive assay system is simulated using the computer models of the assay system, and the resultant output is compared with the known input to assess the total uncertainty. The supporting steps in performing the uncertainty analysis for the passive assay measurements in particular are as follows: (1) Create simulated waste drums and associated conditions; (2) Simulate measurements to determine the basic counting data that would be produced by the PAN assay system under the conditions specified; and (3) Apply the PAN assay system analysis algorithm to the set of counting data produced by simulating measurements to determine the measured plutonium mass. The validity of this simulation approach was verified by comparing simulated output against results from actual measurements using known plutonium sources and surrogate waste drums. The computer simulation of the PAN system performance uses the Monte Carlo N-Particle (MCNP) Code System to produce a neutron transport calculation for a simulated waste drum. Specifically, the passive system uses the neutron coincidence counting technique, utilizing the spontaneous fission of 240 Pu. MCNP application to the SWEPP PAN assay system uncertainty analysis has been very useful for a variety of waste types contained in 208-ell drums measured by a passive radioassay system. The application of MCNP to the active radioassay system is also feasible

Early experience with formalin-fixed paraffin-embedded (FFPE) based commercial clinical genomic profiling of gliomas-robust and informative with caveats.

Science.gov (United States)

Movassaghi, Masoud; Shabihkhani, Maryam; Hojat, Seyed A; Williams, Ryan R; Chung, Lawrance K; Im, Kyuseok; Lucey, Gregory M; Wei, Bowen; Mareninov, Sergey; Wang, Michael W; Ng, Denise W; Tashjian, Randy S; Magaki, Shino; Perez-Rosendahl, Mari; Yang, Isaac; Khanlou, Negar; Vinters, Harry V; Liau, Linda M; Nghiemphu, Phioanh L; Lai, Albert; Cloughesy, Timothy F; Yong, William H

2017-08-01

exhaustively independently validate a commercial genomic profiling assay, examination of a few markers provides some reassurance of its robustness. While potential targeted drugs are recommended based on genetic alterations, to date most targeted therapies have failed in glioblasomas so the usefulness of such recommendations will increase with development of novel and efficacious drugs. Copyright © 2017. Published by Elsevier Inc.

Dengue Virus NS1 Protein as a Diagnostic Marker: Commercially Available ELISA and Comparison to qRT-PCR and Serological Diagnostic Assays Currently Used by the State of Florida

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Jason H. Ambrose

2017-01-01

Full Text Available Background. The proper management of patients infected with dengue virus requires early detection. Here, real-time molecular assays have proven useful but have limitations, whereas ELISAs that detect antibodies are still favored but results are obtained too late to be of clinical value. The production of DENV NS1 peaks early during infection and its detection can combine the advantages of both diagnostic approaches. Methods. This study compared assays currently used for detecting DENV infection at the Florida Department of Health including anti-DENV IgM and IgG ELISAs as well as qRT-PCR, against a commercially available DENV NS1 ELISA. These comparisons were made among a group of 21 human sera. Results. Nine of 14 (64.3% DENV qRT-PCR+ samples were also DENV NS1+. Interestingly, the 5 NS1− samples that were qRT-PCR+ were additionally IgM− and IgG+ suggesting a nonprimary infection. Compared to qRT-PCR, the NS1 assay had a sensitivity of 64.3%, specificity 100%, PPV of 100%, and NPV of 58.3%. Conclusions. The NS1 ELISA performed as expected in known DENV qRT-PCR+ samples; however negative NS1 results for qRT-PCR+ and IgG+ sera seemingly reduced the usefulness of the NS1 ELISA for nonprimary cases. We therefore conclude that diagnosis obtained via DENV NS1 ELISA deserves further investigation.

Validation of the (Troponin-only) Manchester ACS decision aid with a contemporary cardiac troponin I assay.

Science.gov (United States)

Va Den Berg, Patricia; Burrows, Gillian; Lewis, Philip; Carley, Simon; Body, Richard

2018-04-01

The Manchester Acute Coronary Syndromes (MACS) decision aid can 'rules in' and 'rule out' acute coronary syndromes (ACS) by combining a patient's symptoms with the results of a single blood test taken at the time of arrival in the Emergency Department (ED). The original model (MACS) included two biomarkers: high sensitivity cardiac troponin T (hs-cTnT) and heart-type fatty acid binding protein (h-FABP). A refined model without h-FABP was found to have comparable sensitivity but greater specificity. We sought to validate MACS and T-MACS using the contemporary Siemens Advia Centaur cardiac troponin I assay to increase usability in practice. This is a secondary analysis from prospective diagnostic cohort study at Stepping Hill Hospital, United Kingdom. Patients presenting with chest pain of suspected cardiac nature warranting rule out for ACS were included. All patients underwent hs-cTnT testing at least 12h after peak symptoms. The primary outcome was a diagnosis of ACS, defined as either prevalent acute myocardial infarction (AMI) or incident major adverse cardiac events (death, AMI or coronary revascularization) within 30days. Of 405 included patients, 76 (18.8%) had ACS. MACS and T-MACS had similar C-statistics (0.94 for each, p=0.36) and sensitivity (difference 1.3%, 95% CI -1.3 to 3.9%, p=1.00) but T-MACS had significantly greater specificity (difference 16.7%, 95% CI 14.6-18.9%, p<0.0001). T-MACS and MACS would have allowed 36.3% and 22.5% patients to be immediately discharged respectively. Of patients classified as 'very low risk', none had ACS when MACS was used compared to one (0.7%) with T-MACS. Both MACS and T-MACS effectively ruled out ACS even with a contemporary troponin I assay and could be used to reduce unnecessary hospital admissions. Copyright © 2017. Published by Elsevier Inc.

Development and validation of a chiral high-performance liquid chromatography assay for rogletimide and rogletimide-N-oxide isomers in plasma.

Science.gov (United States)

Etienne, M C; Oster, W; Milano, G

1996-01-01

The purpose of the present study was to develop and validate a stereo-specific high-performance liquid chromatography (HPLC) assay for rogletimide (Rog) and rogletimide-N-oxide (Nox) isomers in plasma. The assay was performed with a chiral cellulose-[4-methylbenzoate]ester column (Chiracel OJ). Optimal separation was achieved isocratically with a mobile phase consisting of n-hexane/anhydrous ethanol (65/35, v/v) at a flow rate of 0.9 ml/min, with the column being thermostated at +35 degrees C (UV detection at 257 nm). Under these conditions, retention times were approximately 17, 28, 31 and 76 min for R-Rog, S-Rog, R-Nox and S-Nox, respectively. S-aminoglutethimide (S-Ag) served as the internal standard (retention time 70 min). An extraction procedure from plasma samples was developed on Bond Elut RP8 500-mg cartridges; conditioning was performed with 5 ml methanol and 5 ml water, after which 1 ml plasma that had previously been spiked with 5 microM S-Ag was applied. Washing was done with 6 ml water and elution, with 4 ml methanol. After evaporation to dryness, residues were dissolved in 400 microliters anhydrous ethanol and 12-48 microliters was injected onto the HPLC system. Blank plasma from healthy donors showed the random presence of a small interference eluting at the retention time of R-Rog, precluding the accurate quantification of R-Rog concentrations below 2.5 microM. Reproducibility assays demonstrated the need to use an internal standard. Taking into account the internal standard, at 2.5 microM the intra- and inter-assay coefficients of variation were 10.5% and 21.0% for R-Rog 5.5% and 8.7% for S-Rog, 7.6% and 20.8% for R-Nox and 11.7% and 6.4% for S-Nox, respectively. The detection limit was 2.5 microM for R-Rog, 0.5 microM for S-Rog, 0.25 microM for R-Nox and 0.5 microM for S-Nox. Linearity was satisfactory at concentrations ranging from 2.5 to 10 microM for R-Rog, from 0.5 to 10 microM for S-Rog, from 0.25 to 2.5 microM for R-Nox and from 0.50 to 2

Phenotypic assays for the determination of coreceptor tropism in HIV-1 infected individuals.

Science.gov (United States)

Braun, Patrick; Wiesmann, Frank

2007-10-15

Coreceptor tropism antagonists represent a new class of antiretrovirals for the treatment of HIV infection. The knowledge of patients' viral population tropism before the initiation of and during therapy with such compounds may be critical in order to optimize treatment strategies. In this review we focus on the characteristics of phenotypic assays for the determination of HIV coreceptor tropism. Beside traditional phenotypic assays, there are at least four phenotypic recombinant virus assays (RVA) available to predict coreceptor usage: Trofile (Monogram Biosciences), Phenoscript (VIRalliance), XtrackC/ PhenX-R (inPheno) and a platform developed by Virco. Trofile and Phenoscript represent single-cycle assays and are able to determine coreceptor tropism without cocultivation of HIV particles in cell culture. Trofile offers the most clinically validated data with currently about 25,000 analysed samples. The detection of minority variants is a limitation of all population-based assays and varies between 1 and 10%, depending on the assay used. XtrackC/PhenX-R and Virco's platform combine genotypic and phenotypic assays to analyze a patient's sample for tropism. Although all assays are validated for the assessment of coreceptor tropism in different HIV-1 subtypes, there is still a need for further evaluations. Furthermore, the establishment of cut-offs for X4 minority species will be difficult, and is affected by many factors like patient sample quality, the input volume, viral load, the detection limits and PCR variations. Overall, RVAs confirm efficiency and accuracy thus making them suitable for the clinical management of HIV infected individuals treated with coreceptor antagonists.

Analytical validation of a reference laboratory ELISA for the detection of feline leukemia virus p27 antigen.

Science.gov (United States)

Buch, Jesse S; Clark, Genevieve H; Cahill, Roberta; Thatcher, Brendon; Smith, Peter; Chandrashekar, Ramaswamy; Leutenegger, Christian M; O'Connor, Thomas P; Beall, Melissa J

2017-09-01

Feline leukemia virus (FeLV) is an oncogenic retrovirus of cats. Immunoassays for the p27 core protein of FeLV aid in the detection of FeLV infections. Commercial microtiter-plate ELISAs have rapid protocols and visual result interpretation, limiting their usefulness in high-throughput situations. The purpose of our study was to validate the PetChek FeLV 15 ELISA, which is designed for the reference laboratory, and incorporates sequential, orthogonal screening and confirmatory protocols. A cutoff for the screening assay was established with 100% accuracy using 309 feline samples (244 negative, 65 positive) defined by the combined results of FeLV PCR and an independent reference p27 antigen ELISA. Precision of the screening assay was measured using a panel of 3 samples (negative, low-positive, and high-positive). The intra-assay coefficient of variation (CV) was 3.9-7.9%; the inter-assay CV was 6.0-8.6%. For the confirmatory assay, the intra-assay CV was 3.0-4.7%, and the inter-assay CV was 7.4-9.7%. The analytical sensitivity for p27 antigen was 3.7 ng/mL for inactivated whole FeLV and 1.2 ng/mL for purified recombinant FeLV p27. Analytical specificity was demonstrated based on the absence of cross-reactivity to related retroviruses. No interference was observed for samples containing added bilirubin, hemoglobin, or lipids. Based on these results, the new high-throughput design of the PetChek FeLV 15 ELISA makes it suitable for use in reference laboratory settings and maintains overall analytical performance.

Cross-species assay validation using the AOP “deiodinase inhibition leading to impaired posterior chamber inflation”

Science.gov (United States)

High throughput screening assays able to detect chemical interactions with specific biological targets are increasingly being used to identify chemicals that could be hazardous to humans or wildlife. Most of these assays examine interaction with mammalian proteins. The present wo...

Newborn Congenital Cytomegalovirus Screening Based on Clinical Manifestations and Evaluation of DNA-based Assays for In Vitro Diagnostics.

Science.gov (United States)

Fujii, Tomoyuki; Oka, Akira; Morioka, Ichiro; Moriuchi, Hiroyuki; Koyano, Shin; Yamada, Hideto; Saito, Shigeru; Sameshima, Hiroshi; Nagamatsu, Takeshi; Tsuchida, Shinya; Inoue, Naoki

2017-10-01

To establish a strategy for congenital cytomegalovirus (cCMV) screening and to establish confirmatory assays approved as in vitro diagnostics by the regulatory authorities, we evaluated the clinical risks and performance of diagnostic assays developed by commercial companies, since cCMV infection has significant clinical consequences. Newborns with clinical manifestations considered to be consequences of cCMV infection (n = 575) were screened for the presence of cytomegalovirus (CMV) DNA in urine specimens collected onto filter paper placed in their diapers using the polymerase chain reaction-based assay reported previously. Liquid urine specimens were obtained from all of 20 CMV-positive newborns and 107 of the CMV-negative newborns identified in the screening. We used these 127 specimens, as well as 12 from cCMV cases identified in a previous study and 41 from healthy newborns, to compare the performance of 2 commercial assays and 1 in-house assay. The risk-based screening allowed the identification of cCMV cases at least 10-fold more efficiently than our previous universal screening, although there appears to be a limit to the identification of asymptomatically infected newborns. Although CMV-specific IgM during pregnancy was found frequently in mothers of cCMV newborns, CMV-IgM alone is not an effective diagnostic marker. The urine-filter-based assay and the 3 diagnostic assays yielded identical results. Although risk-based and universal newborn screening strategies for cCMV infection each have their respective advantages and disadvantages, urine-filter-based assay followed by confirmatory in vitro diagnostics assays is able to identify cCMV cases efficiently.

Development of Indirect Competitive Immuno-Assay Method Using SPR Detection for Rapid and Highly Sensitive Measurement of Salivary Cortisol Levels

International Nuclear Information System (INIS)

Tahara, Yusuke; Huang, Zhe; Kiritoshi, Tetsuro; Onodera, Takeshi; Toko, Kiyoshi

2014-01-01

The monitoring of salivary cortisol as a key biomarker of an individual’s stress response has been increasingly focused on. This paper describes the development of a novel cortisol immuno-assay method based on an indirect competitive method using a commercially available surface plasmon resonance instrument. The surface of an Au chip was modified with PEG6-COOH aromatic dialkanethiol self-assembled monolayers and hydrocortisone 3-(O-carboxymethyl) oxime (hydrocortisone 3-CMO) as a cortisol analog. A detection limit of 38 ppt range with a measurement range of 10 ppt–100 ppb was accomplished without the incubation of a mixing solution consisting of standard cortisol and an anti-cortisol antibody, and the time for quantification of cortisol concentration was 8 min from the sample injection. We experimentally compared our immuno-assay with a commercialized salivary cortisol enzyme-linked immunosorbent assay (ELISA) kit using human saliva samples. It was found that the results obtained by the cortisol immuno-assay had a good correlation with those obtained by ELISA assay (R = 0.96). Our findings indicate the potential utility of the cortisol immuno-assay for measurements of human salivary cortisol levels.

Development of Indirect Competitive Immuno-Assay Method Using SPR Detection for Rapid and Highly Sensitive Measurement of Salivary Cortisol Levels

Energy Technology Data Exchange (ETDEWEB)

Tahara, Yusuke; Huang, Zhe; Kiritoshi, Tetsuro [Graduate School of Information Science and Electrical Engineering, Kyushu University, Fukuoka (Japan); Onodera, Takeshi [Research and Development Center for Taste and Odor Sensing, Kyushu University, Fukuoka (Japan); Toko, Kiyoshi, E-mail: toko@ed.kyushu-u.ac.jp [Graduate School of Information Science and Electrical Engineering, Kyushu University, Fukuoka (Japan); Research and Development Center for Taste and Odor Sensing, Kyushu University, Fukuoka (Japan)

2014-05-30

The monitoring of salivary cortisol as a key biomarker of an individual’s stress response has been increasingly focused on. This paper describes the development of a novel cortisol immuno-assay method based on an indirect competitive method using a commercially available surface plasmon resonance instrument. The surface of an Au chip was modified with PEG6-COOH aromatic dialkanethiol self-assembled monolayers and hydrocortisone 3-(O-carboxymethyl) oxime (hydrocortisone 3-CMO) as a cortisol analog. A detection limit of 38 ppt range with a measurement range of 10 ppt–100 ppb was accomplished without the incubation of a mixing solution consisting of standard cortisol and an anti-cortisol antibody, and the time for quantification of cortisol concentration was 8 min from the sample injection. We experimentally compared our immuno-assay with a commercialized salivary cortisol enzyme-linked immunosorbent assay (ELISA) kit using human saliva samples. It was found that the results obtained by the cortisol immuno-assay had a good correlation with those obtained by ELISA assay (R = 0.96). Our findings indicate the potential utility of the cortisol immuno-assay for measurements of human salivary cortisol levels.

A substrate-optimized electrophoretic mobility shift assay for ADAM12

DEFF Research Database (Denmark)

Kotzsch, Alexander; Skovgaard, Tine; Buus, Uwe

2014-01-01

long been investigated as pharmaceutical drug targets; however, due to lack of potency and in vivo side effects, none of the small-molecule inhibitors discovered so far has made it beyond clinical testing. Ongoing research on novel selective inhibitors of ADAMs requires reliable biochemical assays...... to validate molecular probes from large-scale screening efforts. Here we describe an electrophoretic mobility shift assay for ADAM12 based on the identification of an optimized peptide substrate that is characterized by excellent performance and reproducibility....

Assay of serum ferritin by two different radioimmunometric methods and its clinical significance

International Nuclear Information System (INIS)

Kaltwasser, J.P.; Werner, E.; Gesellschaft fuer Strahlen- und Umweltforschung m.b.H., Frankfurt am Main

1977-01-01

Serum ferritin was measured by two different radioimmunometric methods a) the Addison assay, b) a commercial radioimmunoassay. Iron storage in the body was determined using 59 Fe. A dose correlation was found between serum ferritin and iron storage in the body. (AJ) [de

Development and validation of an assay for the simultaneous determination of zidovudine, abacavir, emtricitabine, lamivudine, tenofovir and ribavirin in human plasma using liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Kromdijk, W; Pereira, S A; Rosing, H; Mulder, J W; Beijnen, J H; Huitema, A D R

2013-03-01

This paper describes the development and validation of an assay for the simultaneous quantification of the antiviral and antiretroviral drugs zidovudine, abacavir, emtricitabine, lamivudine, tenofovir and ribavirin in human plasma using liquid chromatography coupled to tandem mass spectrometry. Sample pretreatment consisted of protein precipitation with 0.1% (v/v) formic acid in methanol, evaporation and reconstitution. Chromatographic separation was performed on a Synergy Polar reversed phase C18 column (150 mm × 2.0 mm ID, particle size 4 μm) using a stepwise gradient with 0.1% (v/v) formic acid in water and 0.1% (v/v) formic acid in methanol at a flow rate of 300 μL/min. A triple quadrupole mass spectrometer operating in the positive ionization mode was used for drug detection and quantification. Isotopically labeled zidovudine, lamivudine, tenofovir and ribavirin were used as internal standards. The method was validated over a clinical range of 20-2500 ng/mL for zidovudine, lamivudine and tenofovir, 4-500 ng/mL for abacavir and emtricitabine and 160-20,000 ng/mL for ribavirin. The inter and intra-assay accuracies and precisions were between -8.47% and 14.2% for zidovudine, emtricitabine and ribavirin. For abacavir, lamivudine and tenofovir, the inter and intra-assay accuracies and precisions at the lower limit of quantification were between -11.0% and 18.3%, whereas at all other levels these accuracies and precisions were between -11.7% and 12.0%. The described method is suitable for the determination of zidovudine, abacavir, emtricitabine, lamivudine, tenofovir and ribavirin in human plasma in clinical practice to monitor plasma concentrations in selected cases to optimize therapy. Copyright © 2013. Published by Elsevier B.V.

The evaluation of domestic immunoradiometric assay kit for alpha-fetoprotein

International Nuclear Information System (INIS)

Won, Kyoung Sook; Ryu, Jin Sook; Moon, Dae Hyuk; Lee, Hee Kyung

2000-01-01

Although α-fetoprotein is one of the most commonly used tumor markers in Korea, most of the radioimmunoassay kits for α-fetoprotein have been imported from foreign countries. The purpose of this study was to evaluate the performance of a recently developed domestic immunoradiometric kit for α-fetoprotein (Riakey AFP IRMA CT R , Sin-Jin Medics, Seoul, Korea). We evaluated intra-and inter-assay precision, recovery rate, parallelism, and sensitivity of serum α-fetoprotein measurement using Riakey AFP IRMA CT R kit. The values of α-fetoprotein measured by Riakey AFP IRMA CT R kit were compared with those measured by two foreign commercial kits (α-fetoproteina of Radim and α-feto.riabead of Abbott). Intra-assay coefficients of variation on three different levels were 5.3% for 18.9 ng/ml, 3.4% for 133 ng/ml and 1.6% for 330 ng/ml. Inter-assay coefficients of variation were 9.7% for 20.9 ng/ml, 3.2% for 137 ng/ml and 4.1% for 330 ng/ml respectively. Recovery rate tests on all three different levels showed within 100±10%. Parallelism was also good and the sensitivity was 0.63 ng/ml. There was strong correlation between the measurement of α-fetoprotein by Riakey AFP IRMA CT R and that by two foreign commercial kits(r=3D0.98). The first Korean domestic immunoradiometric kit for α-fetoprotein, Riakey AFP IRMA CT R , performed well for clinical use.=20

A novel mini-DNA barcoding assay to identify processed fins from internationally protected shark species.

Science.gov (United States)

Fields, Andrew T; Abercrombie, Debra L; Eng, Rowena; Feldheim, Kevin; Chapman, Demian D

2015-01-01

There is a growing need to identify shark products in trade, in part due to the recent listing of five commercially important species on the Appendices of the Convention on International Trade in Endangered Species (CITES; porbeagle, Lamna nasus, oceanic whitetip, Carcharhinus longimanus scalloped hammerhead, Sphyrna lewini, smooth hammerhead, S. zygaena and great hammerhead S. mokarran) in addition to three species listed in the early part of this century (whale, Rhincodon typus, basking, Cetorhinus maximus, and white, Carcharodon carcharias). Shark fins are traded internationally to supply the Asian dried seafood market, in which they are used to make the luxury dish shark fin soup. Shark fins usually enter international trade with their skin still intact and can be identified using morphological characters or standard DNA-barcoding approaches. Once they reach Asia and are traded in this region the skin is removed and they are treated with chemicals that eliminate many key diagnostic characters and degrade their DNA ("processed fins"). Here, we present a validated mini-barcode assay based on partial sequences of the cytochrome oxidase I gene that can reliably identify the processed fins of seven of the eight CITES listed shark species. We also demonstrate that the assay can even frequently identify the species or genus of origin of shark fin soup (31 out of 50 samples).

A novel mini-DNA barcoding assay to identify processed fins from internationally protected shark species.

Directory of Open Access Journals (Sweden)

Andrew T Fields

Full Text Available There is a growing need to identify shark products in trade, in part due to the recent listing of five commercially important species on the Appendices of the Convention on International Trade in Endangered Species (CITES; porbeagle, Lamna nasus, oceanic whitetip, Carcharhinus longimanus scalloped hammerhead, Sphyrna lewini, smooth hammerhead, S. zygaena and great hammerhead S. mokarran in addition to three species listed in the early part of this century (whale, Rhincodon typus, basking, Cetorhinus maximus, and white, Carcharodon carcharias. Shark fins are traded internationally to supply the Asian dried seafood market, in which they are used to make the luxury dish shark fin soup. Shark fins usually enter international trade with their skin still intact and can be identified using morphological characters or standard DNA-barcoding approaches. Once they reach Asia and are traded in this region the skin is removed and they are treated with chemicals that eliminate many key diagnostic characters and degrade their DNA ("processed fins". Here, we present a validated mini-barcode assay based on partial sequences of the cytochrome oxidase I gene that can reliably identify the processed fins of seven of the eight CITES listed shark species. We also demonstrate that the assay can even frequently identify the species or genus of origin of shark fin soup (31 out of 50 samples.

TRU waste-assay instrumentation and application in nuclear-facility decommissioning

International Nuclear Information System (INIS)

Umbarger, C.J.

1982-01-01

The Los Alamos TRU waste assay program is developing measurement techniques for TRU and other radioactive waste materials generated by the nuclear industry, including decommissioning programs. Systems are now being fielded for test and evaluation purposes at DOE TRU waste generators. The transfer of this technology to other facilities and the commercial instrumentation sector is well in progress. 6 figures

Variability in assays used for detection of lentiviral infection in bobcats (Lynx rufus), pumas (Puma concolor), and ocelots (Leopardus pardalis)

Science.gov (United States)

Franklin, S.P.; Troyer, J.L.; TerWee, J.A.; Lyren, L.M.; Kays, R.W.; Riley, S.P.D.; Boyce, W.M.; Crooks, K.R.; VandeWoude, S.

2007-01-01

Although lentiviruses similar to feline immunodeficiency virus (FIV) are known to infect numerous felid species, the relative utility of assays used for detecting lentiviral infection has not been compared for many of these hosts. We tested bobcats (Lynx rufus), pumas (Felis concolor), and ocelots (Leopardus pardalis) for exposure to lentivirus using five different assays: puma lentivirus (PLV), African lion lentivirus (LLV), and domestic cat FIV-based immunoblots, a commercially available enzyme-linked immunosorbent assay (ELISA) kit, and nested polymerase chain reaction (PCR). Puma lentivirus immunoblots identified more seropositive individuals than the other antibody-detection assays. The commercial ELISA provided a fair ability to recognize seropositive samples when compared with PLV immunoblot for screening bobcats and ocelots, but not pumas. Polymerase chain reaction identified fewer positive samples than PLV immunoblot for all three species. Immunoblot results were equivalent whether the sample tested was serum, plasma, or whole blood. The results from this study and previous investigations suggest that the PLV immunoblot has the greatest ability to detect reactive samples when screening wild felids of North America and is unlikely to produce false positive results. However, the commercial ELISA kit may provide ap adequate alternative for screening of some species and is more easily adapted to field conditions. ?? Wildlife Disease Association 2007.

Electrochemical mechanism and kinetics studies of haloperidol and its assay in commercial formulations

International Nuclear Information System (INIS)

Ribeiro, Francisco W.P.; Soares, Janete E.S.; Becker, Helena; De Souza, Djenaine; Lima-Neto, Pedro de; Correia, Adriana N.

2011-01-01

The kinetics and mechanism for electrochemical reduction of haloperidol, a psychotherapeutic drug used in the treatment of schizophrenia, were studied using square wave and cyclic voltammetries allied to a hanging mercury drop electrode. The experimental and voltammetric parameters were optimized at 0.04 mol L -1 Brinton-Robinson buffer (pH 10), with a pulse potential frequency of 100 s -1 , a pulse amplitude of 30 mV and scan increment of 2 mV. Two well-defined peaks were observed, which exhibited properties of fast electron transfer with a strong adsorption process of reactants and products on the electrode surface. The first peak was related to a fast and reversible anion-radical formation originating from the reduction of the carbonyl group, and the second was related to the irreversible reduction of the anion-radical previously formed. Analytical parameters such as: linearity range, equation of the analytical curves, correlation coefficients, detection and quantification limits, recovery efficiency, and relative standard deviation for intraday and interday were compared to similar results obtained by use of the UV-vis spectrophotometry technique, and the analytical results obtained in commercial formulations show that the voltammetric procedure using a hanging mercury drop electrode is suitable for analyzing haloperidol in complex commercial formulation samples.

Electrochemical mechanism and kinetics studies of haloperidol and its assay in commercial formulations

Energy Technology Data Exchange (ETDEWEB)

Ribeiro, Francisco W.P. [Departamento de Quimica Analitica e Fisico-Quimica, Centro de Ciencias, Universidade Federal do Ceara, Bloco 940 Campus do Pici 60455-970, Fortaleza, CE (Brazil); Soares, Janete E.S. [Departamento de Farmacia, Faculdade de Farmacia, Odontologia e Enfermagem, Universidade Federal do Ceara, Rua Capitao Francisco Pedro, 1210 Rodolfo Teofilo 60430-370, Fortaleza, CE (Brazil); Becker, Helena; De Souza, Djenaine; Lima-Neto, Pedro de [Departamento de Quimica Analitica e Fisico-Quimica, Centro de Ciencias, Universidade Federal do Ceara, Bloco 940 Campus do Pici 60455-970, Fortaleza, CE (Brazil); Correia, Adriana N., E-mail: adriana@ufc.b [Departamento de Quimica Analitica e Fisico-Quimica, Centro de Ciencias, Universidade Federal do Ceara, Bloco 940 Campus do Pici 60455-970, Fortaleza, CE (Brazil)

2011-02-01

The kinetics and mechanism for electrochemical reduction of haloperidol, a psychotherapeutic drug used in the treatment of schizophrenia, were studied using square wave and cyclic voltammetries allied to a hanging mercury drop electrode. The experimental and voltammetric parameters were optimized at 0.04 mol L{sup -1} Brinton-Robinson buffer (pH 10), with a pulse potential frequency of 100 s{sup -1}, a pulse amplitude of 30 mV and scan increment of 2 mV. Two well-defined peaks were observed, which exhibited properties of fast electron transfer with a strong adsorption process of reactants and products on the electrode surface. The first peak was related to a fast and reversible anion-radical formation originating from the reduction of the carbonyl group, and the second was related to the irreversible reduction of the anion-radical previously formed. Analytical parameters such as: linearity range, equation of the analytical curves, correlation coefficients, detection and quantification limits, recovery efficiency, and relative standard deviation for intraday and interday were compared to similar results obtained by use of the UV-vis spectrophotometry technique, and the analytical results obtained in commercial formulations show that the voltammetric procedure using a hanging mercury drop electrode is suitable for analyzing haloperidol in complex commercial formulation samples.

Transuranic waste assay instrumentation: new developments and directions at the Los Alamos Scientific Laboratory

Energy Technology Data Exchange (ETDEWEB)

Close, D.A.; Umbarger, C.J.; West, L.; Smith, W.J.; Cates, M.R.; Noel, B.W.; Honey, F.J.; Franks, L.A.; Pigg, J.L.; Trundle, A.S.

1978-01-01

The Los Alamos Scientific Laboratory is developing assay instrumentation for the quantitative analysis of transuranic materials found in bulk solid wastes generated by Department of Energy facilities and by the commercial nuclear power industry. This also includes wastes generated in the decontamination and decommissioning of facilities and wastes generated during burial ground exhumation. The assay instrumentation will have a detection capability for the transuranics of less than 10 nCi of activity per gram of waste whenever practicable.

Transuranic waste assay instrumentation: new developments and directions at the Los Alamos Scientific Laboratory

International Nuclear Information System (INIS)

Close, D.A.; Umbarger, C.J.; West, L.; Smith, W.J.; Cates, M.R.; Noel, B.W.; Honey, F.J.; Franks, L.A.; Pigg, J.L.; Trundle, A.S.

1978-01-01

The Los Alamos Scientific Laboratory is developing assay instrumentation for the quantitative analysis of transuranic materials found in bulk solid wastes generated by Department of Energy facilities and by the commercial nuclear power industry. This also includes wastes generated in the decontamination and decommissioning of facilities and wastes generated during burial ground exhumation. The assay instrumentation will have a detection capability for the transuranics of less than 10 nCi of activity per gram of waste whenever practicable

Radioligand purification prior to routine receptor assays

International Nuclear Information System (INIS)

Le Goff, J.-M.; Berthois, Y.; Martin, P.-M.

1988-01-01

The need to repurify the commercially available radioligands [ 3 H]estradiol and [ 3 H]testosterone before use in routine assays was investigated. Storage of these products for 2 months after delivery led to appreciable degradation of [ 3 H]estradiol compared to [ 3 H]testosterone. Unexpectedly, TLC and even HPLC procedures were ineffective in completely restoring the purity of [ 3 H]-estradiol and the unremoved polar products induced important variations in our estrogen receptor assays. An increase in non-specific binding and a concomitant decrease in total binding were observed resulting in an underestimation of specific binding sites and of the affinity constant. In some cases Scatchard analysis was not possible. The authors therefore strongly recommend the repurification of low-stability radioligands and propose an economic time-saving procedure for the purification of [ 3 H]estradiol by solvent differential partition which requires no high-cost investment in apparatus. (author)

Development and validation of PCR-based assays for diagnosis of American cutaneous leishmaniasis and identificatio nof the parasite species

Directory of Open Access Journals (Sweden)

Grazielle Cardoso da Graça

2012-08-01

Full Text Available In this study, PCR assays targeting different Leishmania heat-shock protein 70 gene (hsp70 regions, producing fragments ranging in size from 230-390 bp were developed and evaluated to determine their potential as a tool for the specific molecular diagnosis of cutaneous leishmaniasis (CL. A total of 70 Leishmania strains were analysed, including seven reference strains (RS and 63 previously typed strains. Analysis of the RS indicated a specific region of 234 bp in the hsp70 gene as a valid target that was highly sensitive for detection of Leishmania species DNA with capacity of distinguishing all analyzed species, after polymerase chain reaction-restriction fragment length polymorfism (PCR-RFLP. This PCR assay was compared with other PCR targets used for the molecular diagnosis of leishmaniasis: hsp70 (1400-bp region, internal transcribed spacer (ITS1 and glucose-6-phosphate dehydrogenase (G6pd. A good agreement among the methods was observed concerning the Leishmania species identification. Moreover, to evaluate the potential for molecular diagnosis, we compared the PCR targets hsp70-234 bp, ITS1, G6pd and mkDNA using a panel of 99 DNA samples from tissue fragments collected from patients with confirmed CL. Both PCR-hsp70-234 bp and PCR-ITS1 detected Leishmania DNA in more than 70% of the samples. However, using hsp70-234 bp PCR-RFLP, identification of all of the Leishmania species associated with CL in Brazil can be achieved employing a simpler and cheaper electrophoresis protocol.

Novel and validated titrimetric method for determination of selected angiotensin-II-receptor antagonists in pharmaceutical preparations and its comparison with UV spectrophotometric determination

Directory of Open Access Journals (Sweden)

Shrikant H. Patil

2012-12-01

Full Text Available A novel and simple titrimetric method for determination of commonly used angiotensin-II-receptor antagonists (ARA-IIs is developed and validated. The direct acid base titration of four ARA-IIs, namely eprosartan mesylate, irbesartan, telmisartan and valsartan, was carried out in the mixture of ethanol:water (1:1 as solvent using standardized sodium hydroxide aqueous solution as titrant, either visually using phenolphthalein as an indicator or potentiometrically using combined pH electrode. The method was found to be accurate and precise, having relative standard deviation of less than 2% for all ARA-IIs studied. Also, it was shown that the method could be successfully applied to the assay of commercial pharmaceuticals containing the above-mentioned ARA-IIs. The validity of the method was tested by the recovery studies of standard addition to pharmaceuticals and the results were found to be satisfactory. Results obtained by this method were found to be in good agreement with those obtained by UV spectrophotometric method. For UV spectrophotometric analysis ethanol was used as a solvent and wavelength of 233 nm, 246 nm, 296 nm, and 250 nm was selected for determination of eprosartan mesylate, irbesartan, telmisartan, and valsartan respectively. The proposed titrimetric method is simple, rapid, convenient and sufficiently precise for quality control purposes. Keywords: Angiotensin-II-receptor antagonists, Titrimetric assay, UV spectrophotometry, Validation

A Comparison of Real-Time and Endpoint Cell Viability Assays for Improved Synthetic Lethal Drug Validation.

Science.gov (United States)

Single, Andrew; Beetham, Henry; Telford, Bryony J; Guilford, Parry; Chen, Augustine

2015-12-01

Cell viability assays fulfill a central role in drug discovery studies. It is therefore important to understand the advantages and disadvantages of the wide variety of available assay methodologies. In this study, we compared the performance of three endpoint assays (resazurin reduction, CellTiter-Glo, and nuclei enumeration) and two real-time systems (IncuCyte and xCELLigence). Of the endpoint approaches, both the resazurin reduction and CellTiter-Glo assays showed higher cell viabilities when compared directly to stained nuclei counts. The IncuCyte and xCELLigence real-time systems were comparable, and both were particularly effective at tracking the effects of drug treatment on cell proliferation at sub-confluent growth. However, the real-time systems failed to evaluate contrasting cell densities between drug-treated and control-treated cells at full growth confluency. Here, we showed that using real-time systems in combination with endpoint assays alleviates the disadvantages posed by each approach alone, providing a more effective means to evaluate drug toxicity in monolayer cell cultures. Such approaches were shown to be effective in elucidating the toxicity of synthetic lethal drugs in an isogenic pair of MCF10A breast cell lines. © 2015 Society for Laboratory Automation and Screening.

Validation of the Cepheid GeneXpert for Detecting Ebola Virus in Semen.

Science.gov (United States)

Loftis, Amy James; Quellie, Saturday; Chason, Kelly; Sumo, Emmanuel; Toukolon, Mason; Otieno, Yonnie; Ellerbrok, Heinzfried; Hobbs, Marcia M; Hoover, David; Dube, Karine; Wohl, David A; Fischer, William A

2017-02-01

Ebola virus (EBOV) RNA persistence in semen, reported sexual transmission, and sporadic clusters at the end of the 2013-2016 epidemic have prompted recommendations that male survivors refrain from unprotected sex unless their semen is confirmed to be EBOV free. However, there is no fully validated assay for EBOV detection in fluids other than blood. The Cepheid Xpert Ebola assay for EBOV RNA detection was validated for whole semen and blood using samples obtained from uninfected donors and spiked with inactivated EBOV. The validation procedure incorporated standards from Clinical and Laboratory Standards Institute and Good Clinical Laboratory Practices guidelines for evaluating molecular devices for use in infectious disease testing. The assay produced limits of detection of 1000 copies/mL in semen and 275 copies/mL in blood. Limits of detection for both semen and blood increased with longer intervals between collection and testing, with acceptable results obtained up to 72 hours after specimen collection. The Cepheid Xpert Ebola assay is accurate and precise for detecting EBOV in whole semen. A validated assay for EBOV RNA detection in semen informs the care of male survivors of Ebola, as well as recommendations for public health. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

Sensitivity and specificity of four assays to detect human T-lymphotropic virus type I or type I/II antibodies

NARCIS (Netherlands)

Vrielink, H.; Reesink, H. W.; Zaaijer, H. L.; van der Poel, C. L.; Cuypers, H. T.; Lelie, P. N.

1996-01-01

BACKGROUND: Assays that detect human T-lymphotropic virus type I and type II antibody (HTLV-I/II) are widely used in the routine screening of blood donors. STUDY DESIGN AND METHODS: Four commercially available anti-HTLV-I (Fujirebio and Organon Teknika) or -HTLV-I/II assays (Murex and Ortho) were

An indicator cell assay for blood-based diagnostics.

Directory of Open Access Journals (Sweden)

Samuel A Danziger

Full Text Available We have established proof of principle for the Indicator Cell Assay Platform™ (iCAP™, a broadly applicable tool for blood-based diagnostics that uses specifically-selected, standardized cells as biosensors, relying on their innate ability to integrate and respond to diverse signals present in patients' blood. To develop an assay, indicator cells are exposed in vitro to serum from case or control subjects and their global differential response patterns are used to train reliable, disease classifiers based on a small number of features. In a feasibility study, the iCAP detected pre-symptomatic disease in a murine model of amyotrophic lateral sclerosis (ALS with 94% accuracy (p-Value = 3.81E-6 and correctly identified samples from a murine Huntington's disease model as non-carriers of ALS. Beyond the mouse model, in a preliminary human disease study, the iCAP detected early stage Alzheimer's disease with 72% cross-validated accuracy (p-Value = 3.10E-3. For both assays, iCAP features were enriched for disease-related genes, supporting the assay's relevance for disease research.

Sensitive assays enable detection of serum IgG antibodies against Clostridium difficile toxin A and toxin B in healthy subjects and patients with Clostridium difficile infection.

Science.gov (United States)

Zhao, Xuemei; Bender, Florent; Shukla, Rajiv; Kang, John J; Caro-Aguilar, Ivette; Laterza, Omar F

2016-04-01

Pathogenic Clostridium difficile produces two proinflammatory exotoxins, toxin A and toxin B. Low level of serum antitoxin IgG antibodies is a risk factor for the development of primary and recurrent C. difficile infection (CDI). We developed and validated two sensitive, titer-based electrochemiluminescence assays for the detection of serum antibody levels against C. difficile toxins A and B. These assays demonstrated excellent precision. The sensitivity of the assays allowed the detection of antitoxin A and antitoxin B IgG antibodies in all tested serum samples during assay validation. The validated titer-based assays enable assessment of antitoxin A and antitoxin B IgG antibodies as potential biomarkers to identify patients with CDI at increased risk for CDI recurrence.

Development and validation of a real-time PCR assay for specific and sensitive detection of canid herpesvirus 1.

Science.gov (United States)

Decaro, Nicola; Amorisco, Francesca; Desario, Costantina; Lorusso, Eleonora; Camero, Michele; Bellacicco, Anna Lucia; Sciarretta, Rossana; Lucente, Maria Stella; Martella, Vito; Buonavoglia, Canio

2010-10-01

A TaqMan-based real-time PCR assay targeting the glycoprotein B-encoding gene was developed for diagnosis of canid herpesvirus 1 (CHV-1) infection. The established assay was highly specific, since no cross-reactions were observed with other canine DNA viruses, including canine parvovirus type 2, canine minute virus, or canine adenovirus types 1 and 2. The detection limit was 10(1) and 1.20 x 10(1) DNA copies per 10 microl(-1) of template for standard DNA and a CHV-1-positive kidney sample, respectively: about 1-log higher than a gel-based PCR assay targeting the thymidine kinase gene. The assay was also reproducible, as shown by satisfactory low intra-assay and inter-assay coefficients of variation. CHV-1 isolates of different geographical origins were recognised by the TaqMan assay. Tissues and clinical samples collected from three pups which died of CHV-1 neonatal infection were also tested, displaying a wide distribution of CHV-l DNA in their organs. Unlike other CHV-1-specific diagnostic methods, this quantitative assay permits simultaneous detection and quantitation of CHV-1 DNA in a wide range of canine tissues and body fluids, thus providing a useful tool for confirmation of a clinical diagnosis, for the study of viral pathogenesis and for evaluation of the efficacy of vaccines and antiviral drugs. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Validation of a quantitative cerebrospinal fluid alpha-synuclein assay in a European-wide interlaboratory study

DEFF Research Database (Denmark)

Kruse, N.; Persson, S.; Alcolea, D.

2015-01-01

(one lot) were provided centrally and data reported back to one laboratory for data analysis. Our study showed that although factors such as preanalytical sample handling and lot-to-lot variability were minimized by our study design, we identified high variation in absolute values of CSF aSyn even when...... the same samples and same lots of assays were applied. We further demonstrate that although absolute concentrations differ between laboratories the quantitative results are comparable. With further standardization this assay may become an attractive tool for comparing aSyn measurements in diverse settings...... assay (ELISA) for the quantification of aSyn in CSF, we carried out a round robin trial with 18 participating laboratories trained in CSF ELISA analyses within the BIOMARKAPD project in the EU Joint Program -Neurodegenerative Disease Research. CSF samples (homogeneous aliquots from pools) and ELISA kits...

Quantification of imatinib in human serum: validation of a high-performance liquid chromatography-mass spectrometry method for therapeutic drug monitoring and pharmacokinetic assays

Directory of Open Access Journals (Sweden)

Rezende VM

2013-08-01

Full Text Available Vinicius Marcondes Rezende,1 Ariane Rivellis,1 Mafalda Megumi Yoshinaga Novaes,1 Dalton de Alencar Fisher Chamone,2 Israel Bendit1,21Laboratory of Tumor Biology, 2Department of Hematology, School of Medicine, University of São Paulo, São Paulo, BrazilBackground: Imatinib mesylate has been a breakthrough treatment for chronic myeloid leukemia. It has become the ideal tyrosine kinase inhibitor and the standard treatment for chronic-phase leukemia. Striking results have recently been reported, but intolerance to imatinib and noncompliance with treatment remain to be solved. Molecular monitoring by quantitative real-time polymerase chain reaction is the gold standard for monitoring patients, and imatinib blood levels have also become an important tool for monitoring.Methods: A fast and cheap method was developed and validated using high-performance liquid chromatography-mass spectrometry for quantification of imatinib in human serum and tamsulosin as the internal standard. Remarkable advantages of the method includes use of serum instead of plasma, less time spent on processing and analysis, simpler procedures, and requiring reduced amounts of biological material, solvents, and reagents. Stability of the analyte was also studied. This research also intended to drive the validation scheme in clinical centers. The method was validated according to the requirements of the US Food and Drug Administration and Brazilian National Health Surveillance Agency within the range of 0.500–10.0 µg/mL with a limit of detection of 0.155 µg/mL. Stability data for the analyte are also presented.Conclusion: Given that the validated method has proved to be linear, accurate, precise, and robust, it is suitable for pharmacokinetic assays, such as bioavailability and bioequivalence, and is being successfully applied in routine therapeutic drug monitoring in the hospital service.Keywords: imatinib, high-performance liquid chromatography-mass spectrometry, therapeutic

Development and validation of a house finch interleukin-1β (HfIL-1β) ELISA system.

Science.gov (United States)

Kim, Sungwon; Park, Myeongseon; Leon, Ariel E; Adelman, James S; Hawley, Dana M; Dalloul, Rami A

2017-08-30

A unique clade of the bacterium Mycoplasma gallisepticum (MG), which causes chronic respiratory disease in poultry, has resulted in annual epidemics of conjunctivitis in North American house finches since the 1990s. Currently, few immunological tools have been validated for this songbird species. Interleukin-1β (IL-1β) is a prototypic multifunctional cytokine and can affect almost every cell type during Mycoplasma infection. The overall goal of this study was to develop and validate a direct ELISA assay for house finch IL-1β (HfIL-1β) using a cross-reactive chicken antibody. A direct ELISA approach was used to develop this system using two different coating methods, carbonate and dehydration. In both methods, antigens (recombinant HfIL-1b or house finch plasma) were serially diluted in carbonate-bicarbonate coating buffer and either incubated at 4 °C overnight or at 60 °C on a heating block for 2 hr. To generate the standard curve, rHfIL-1b protein was serially diluted at 0, 3, 6, 9, 12, 15, 18, 21, and 24 ng/mL. Following blocking and washing, anti-chicken IL-1b polyclonal antibody was added, plates were later incubated with detecting antibodies, and reactions developed with tetramethylbenzidine solution. A commercially available anti-chicken IL-1β (ChIL-1β) polyclonal antibody (pAb) cross-reacted with house finch plasma IL-1β as well as bacterially expressed recombinant house finch IL-1β (rHfIL-1β) in immunoblotting assays. In a direct ELISA system, rHfIL-1β could not be detected by an anti-ChIL-1β pAb when the antigen was coated with carbonate-bicarbonate buffer at 4°C overnight. However, rHfIL-1β was detected by the anti-ChIL-1β pAb when the antigen was coated using a dehydration method by heat (60°C). Using the developed direct ELISA for HfIL-1β with commercial anti-ChIL-1β pAb, we were able to measure plasma IL-1β levels from house finches. Based on high amino acid sequence homology, we hypothesized and demonstrated cross-reactivity of

Analysis of Citric Acid in Beverages: Use of an Indicator Displacement Assay

Science.gov (United States)

Umali, Alona P.; Anslyn, Eric V.; Wright, Aaron T.; Blieden, Clifford R.; Smith, Carolyne K.; Tian, Tian; Truong, Jennifer A.; Crumm, Caitlin E.; Garcia, Jorge E.; Lee, Soal; Mosier, Meredith; Nguyen, Chester P.

2010-01-01

The use of an indicator displacement assay permits the visualization of binding events between host and guest molecules. An undergraduate laboratory experiment is described to demonstrate the technique in the determination of citric acid content in commercially available beverages such as soda pop and fruit juices. Through the technique, students…

A Rapid Method for Quantifying Viable Mycobacterium avium subsp. paratuberculosis in Cellular Infection Assays

Science.gov (United States)

Pooley, Hannah B.; de Silva, Kumudika; Purdie, Auriol C.; Begg, Douglas J.; Whittington, Richard J.

2016-01-01

ABSTRACT Determining the viability of bacteria is a key outcome of in vitro cellular infection assays. Currently, this is done by culture, which is problematic for fastidious slow-growing bacteria such as Mycobacterium avium subsp. paratuberculosis, where it can take up to 4 months to confirm growth. This study aimed to identify an assay that can rapidly quantify the number of viable M. avium subsp. paratuberculosis cells in a cellular sample. Three commercially available bacterial viability assays along with a modified liquid culture method coupled with high-throughput quantitative PCR growth detection were assessed. Criteria for assessment included the ability of each assay to differentiate live and dead M. avium subsp. paratuberculosis organisms and their accuracy at low bacterial concentrations. Using the culture-based method, M. avium subsp. paratuberculosis growth was reliably detected and quantified within 2 weeks. There was a strong linear association between the 2-week growth rate and the initial inoculum concentration. The number of viable M. avium subsp. paratuberculosis cells in an unknown sample was quantified based on the growth rate, by using growth standards. In contrast, none of the commercially available viability assays were suitable for use with samples from in vitro cellular infection assays. IMPORTANCE Rapid quantification of the viability of Mycobacterium avium subsp. paratuberculosis in samples from in vitro cellular infection assays is important, as it allows these assays to be carried out on a large scale. In vitro cellular infection assays can function as a preliminary screening tool, for vaccine development or antimicrobial screening, and also to extend findings derived from experimental animal trials. Currently, by using culture, it takes up to 4 months to obtain quantifiable results regarding M. avium subsp. paratuberculosis viability after an in vitro infection assay; however, with the quantitative PCR and liquid culture method

Plasma myelin basic protein assay using Gilford enzyme immunoassay cuvettes.

Science.gov (United States)

Groome, N P

1981-10-01

The assay of myelin basic protein in body fluids has potential clinical importance as a routine indicator of demyelination. Preliminary details of a competitive enzyme immunoassay for this protein have previously been published by the author (Groome, N. P. (1980) J. Neurochem. 35, 1409-1417). The present paper now describes the adaptation of this assay for use on human plasma and various aspects of routine data processing. A commercially available cuvette system was found to have advantages over microtitre plates but required a permuted arrangement of sample replicates for consistent results. For dose interpolation, the standard curve could be fitted to a three parameter non-linear equation by regression analysis or linearised by the logit/log transformation.

Development of Two Antibody Detection Enzyme-Linked Immunosorbent Assays for Serodiagnosis of Human Chronic Fascioliasis

Science.gov (United States)

Cabán-Hernández, Kimberly; Gaudier, José F.; Ruiz-Jiménez, Caleb

2014-01-01

Coprological examination based on egg detection in stool samples is currently used as the gold standard for the diagnosis of human fascioliasis. However, this method is not effective during the acute phase of the disease and has poor sensitivity during the chronic phase. Serodiagnosis has become an excellent alternative to coprological examination in efforts to combat the effects of fascioliasis on human and animal health. Two novel recombinant Fasciola hepatica proteins, i.e., a ferritin (FhFtn-1) and a tegument-associated protein (FhTP16.5), were used as antigens to develop in-house enzyme-linked immunosorbent assay (ELISA) methods. The assays were optimized and validated using 152 serum samples from humans with a known infection status, including healthy subjects, patients with chronic fascioliasis, and patients with other parasitic diseases. The FhFtn-1 ELISA was shown to be 96.6% sensitive and 95.7% specific; the respective parameters for the FhTP16.5 ELISA were 91.4% and 92.4%. The performances of the FhFtn-1 and FhTP16.5 ELISAs were compared with that of an available commercial test (the DRG test) using a subset of serum samples. Our in-house tests were slightly more sensitive than the DRG test in detecting antibodies against F. hepatica, but the differences were not statistically significant. In conclusion, the present study provides evidence for the potential of the FhFtn-1 and FhTP16.5 ELISAs as diagnostic tools for human fascioliasis, as might be implemented in conjunction with standard assays for large-scale screenings in areas where the disease is endemic and for the detection of occasional cases in clinical laboratories. PMID:24353000

Development of two antibody detection enzyme-linked immunosorbent assays for serodiagnosis of human chronic fascioliasis.

Science.gov (United States)

Cabán-Hernández, Kimberly; Gaudier, José F; Ruiz-Jiménez, Caleb; Espino, Ana M

2014-03-01

Coprological examination based on egg detection in stool samples is currently used as the gold standard for the diagnosis of human fascioliasis. However, this method is not effective during the acute phase of the disease and has poor sensitivity during the chronic phase. Serodiagnosis has become an excellent alternative to coprological examination in efforts to combat the effects of fascioliasis on human and animal health. Two novel recombinant Fasciola hepatica proteins, i.e., a ferritin (FhFtn-1) and a tegument-associated protein (FhTP16.5), were used as antigens to develop in-house enzyme-linked immunosorbent assay (ELISA) methods. The assays were optimized and validated using 152 serum samples from humans with a known infection status, including healthy subjects, patients with chronic fascioliasis, and patients with other parasitic diseases. The FhFtn-1 ELISA was shown to be 96.6% sensitive and 95.7% specific; the respective parameters for the FhTP16.5 ELISA were 91.4% and 92.4%. The performances of the FhFtn-1 and FhTP16.5 ELISAs were compared with that of an available commercial test (the DRG test) using a subset of serum samples. Our in-house tests were slightly more sensitive than the DRG test in detecting antibodies against F. hepatica, but the differences were not statistically significant. In conclusion, the present study provides evidence for the potential of the FhFtn-1 and FhTP16.5 ELISAs as diagnostic tools for human fascioliasis, as might be implemented in conjunction with standard assays for large-scale screenings in areas where the disease is endemic and for the detection of occasional cases in clinical laboratories.

Modeling of coupled differential equations for cellular chemical signaling pathways: Implications for assay protocols utilized in cellular engineering.

Science.gov (United States)

O'Clock, George D

2016-08-01

Cellular engineering involves modification and control of cell properties, and requires an understanding of fundamentals and mechanisms of action for cellular derived product development. One of the keys to success in cellular engineering involves the quality and validity of results obtained from cell chemical signaling pathway assays. The accuracy of the assay data cannot be verified or assured if the effect of positive feedback, nonlinearities, and interrelationships between cell chemical signaling pathway elements are not understood, modeled, and simulated. Nonlinearities and positive feedback in the cell chemical signaling pathway can produce significant aberrations in assay data collection. Simulating the pathway can reveal potential instability problems that will affect assay results. A simulation, using an electrical analog for the coupled differential equations representing each segment of the pathway, provides an excellent tool for assay validation purposes. With this approach, voltages represent pathway enzyme concentrations and operational amplifier feedback resistance and input resistance values determine pathway gain and rate constants. The understanding provided by pathway modeling and simulation is strategically important in order to establish experimental controls for assay protocol structure, time frames specified between assays, and assay concentration variation limits; to ensure accuracy and reproducibility of results.

Data on the chemical properties of commercial fish sauce products.

Science.gov (United States)

Nakano, Mitsutoshi; Sagane, Yoshimasa; Koizumi, Ryosuke; Nakazawa, Yozo; Yamazaki, Masao; Watanabe, Toshihiro; Takano, Katsumi; Sato, Hiroaki

2017-12-01

This data article reports on the chemical properties of commercial fish sauce products associated with the fish sauce taste and flavor. All products were analyzed in triplicate. Dried solid content was analyzed by moisture analyzer. Fish sauce salinity was determined by a salt meter. pH was measured using a pH meter. The acidity was determined using a titration assay. Amino nitrogen and total nitrogen were evaluated using a titration assay and Combustion-type nitrogen analyzer, respectively. The analyzed products originated from Japan, Thailand, Vietnam, China, the Philippines, and Italy. Data on the chemical properties of the products are provided in table format in the current article.

Application of BALB/c mouse in the local lymph node assay:BrdU-ELISA for the prediction of the skin sensitizing potential of chemicals.

Science.gov (United States)

Hou, Fenxia; Xing, Caihong; Li, Bin; Cheng, Juan; Chen, Wei; Zhang, Man

2015-01-01

Allergic contact dermatitis (ACD) is a skin disease characterized by eczema and itching. A considerable proportion of chemicals induce ACD in humans. More than 10,000 substances should be tested for skin sensitization potential under the Registration, Evaluation, Authorization and Restriction of Chemical substances (REACH) regulation. The Local Lymph Node Assay (LLNA) has been designated as the first-choice in vivo assay for sensitization testing by REACH. The LLNA:BrdU-ELISA is a validated non-radioactive modification to the LLNA. For both the LLNA and the LLNA:BrdU-ELISA, CBA/JN mouse is the preferred mouse strain recommended in the regulatory guidelines. However, the availability of CBA/JN mouse in China is only limited to a few animal suppliers, which makes the mouse difficult to obtain. BALB/c mouse, which is widely commercially available, is considered for alternative use but it can only be used in the assay after it has been evaluated by formal validation study. Thus, a validation study was conducted in our laboratory to determine if BALB/c mouse could also be used in the LLNA:BrdU-ELISA. Forty-three test substances including 32 LLNA sensitizers and 11 LLNA non-sensitizers, their vehicles and each concentration used were the same as that used in the formal validation study for the LLNA:BrdU-ELISA using CBA/JN mouse. Female BALB/c mice of 8-10 weeks old were randomly allocated to groups (four mice per group). The test substance (25 μl) or the vehicle alone was applied to the dorsum of both ears daily for 3 consecutive days. A single intraperitoneal injection of 0.5 ml of BrdU (10mg/ml) solution was given on day 5. On day 6, a pair of auricular lymph nodes from each mouse was excised, weighed and stored at -20°C until BrdU-ELISA was conducted. This validation study for the LLNA:BrdU-ELISA using BALB/c mouse correctly identified 30 of 31 sensitizers and 8 of 11 non-sensitizers. The accuracy, sensitivity, specificity, false positive rate, false negative rate

Qualification of standard membrane-feeding assay with Plasmodium falciparum malaria and potential improvements for future assays.

Directory of Open Access Journals (Sweden)

Kazutoyo Miura

Full Text Available Vaccines that interrupt malaria transmission are of increasing interest and a robust functional assay to measure this activity would promote their development by providing a biologically relevant means of evaluating potential vaccine candidates. Therefore, we aimed to qualify the standard membrane-feeding assay (SMFA. The assay measures the transmission-blocking activity of antibodies by feeding cultured P. falciparum gametocytes to Anopheles mosquitoes in the presence of the test antibodies and measuring subsequent mosquito infection. The International Conference on Harmonisation (ICH Harmonised Tripartite Guideline Q2(R1 details characteristics considered in assay validation. Of these characteristics, we decided to qualify the SMFA for Precision, Linearity, Range and Specificity. The transmission-blocking 4B7 monoclonal antibody was tested over 6 feeding experiments at several concentrations to determine four suitable concentrations that were tested in triplicate in the qualification experiments (3 additional feeds to evaluate Precision, Linearity and Range. For Specificity, 4B7 was tested in the presence of normal mouse IgG. We determined intra- and inter-assay variability of % inhibition of mean oocyst intensity at each concentration of 4B7 (lower concentrations showed higher variability. We also showed that % inhibition was dependent on 4B7 concentration and the activity is specific to 4B7. Since obtaining empirical data is time-consuming, we generated a model using data from all 9 feeds and simulated the effects of different parameters on final readouts to improve the assay procedure and analytical methods for future studies. For example, we estimated the effect of number of mosquitoes dissected on variability of % inhibition, and simulated the relationship between % inhibition in oocyst intensity and % inhibition of prevalence of infected mosquitos at different mean oocysts in the control. SMFA is one of the few biological assays used in

Expert system technology for nondestructive waste assay

International Nuclear Information System (INIS)

Becker, G.K.; Determan, J.C.

1998-01-01

Nondestructive assay waste characterization data generated for use in the National TRU Program must be of known and demonstrable quality. Each measurement is required to receive an independent technical review by a qualified expert. An expert system prototype has been developed to automate waste NDA data review of a passive/active neutron drum counter system. The expert system is designed to yield a confidence rating regarding measurement validity. Expert system rules are derived from data in a process involving data clustering, fuzzy logic, and genetic algorithms. Expert system performance is assessed against confidence assignments elicited from waste NDA domain experts. Performance levels varied for the active, passive shielded, and passive system assay modes of the drum counter system, ranging from 78% to 94% correct classifications

An European inter-laboratory validation of alternative endpoints of the murine local lymph node assay: first round.

Science.gov (United States)

Ehling, G; Hecht, M; Heusener, A; Huesler, J; Gamer, A O; van Loveren, H; Maurer, Th; Riecke, K; Ullmann, L; Ulrich, P; Vandebriel, R; Vohr, H-W

2005-08-15

The new OECD guideline 429 (skin sensitization: local lymph node assay) is based upon a protocol, which utilises the incorporation of radioactivity into DNA as a measure for cell proliferation in vivo. The guideline also enables the use of alternative endpoints in order to assess draining lymph node (LN) cell proliferation. Here we describe the first round of an inter-laboratory validation of alternative endpoints in the LLNA conducted in seven laboratories. The validation study was managed and supervised by the Swiss Agency for Therapeutic Products, Swissmedic. Statistical analyses of all data were performed by an independent centre at the University of Bern, Department of Statistics. Ear-draining, LN weight and cell count were used to assess proliferation instead of radioactive labeling of lymph node cells. In addition, the acute inflammatory skin reaction was measured by ear swelling and weight of circular biopsies of the ears to identify skin irritating properties of the test items. Hexylcinnamaldehyde (HCA) and three blinded test items were applied to female, 8--10 weeks old NMRI and BALB/c mice. Results were sent via the independent study coordinator to the statistician. The results of this first round showed that the alternative endpoints of the LLNA are sensitive and robust parameters. The use of ear weights added an important parameter assessing the skin irritation potential, which supports the differentiation of pure irritative from contact allergenic potential. There were absolute no discrepancies between the categorisation of the three test substances A--C determined by each single participating laboratories. The results highlighted also that many parameters do have an impact on the strength of the responses. Therefore, such parameters have to be taken into consideration for the categorisation of compounds due to their relative sensitizing potencies.

An European inter-laboratory validation of alternative endpoints of the murine local lymph node assay: First round

International Nuclear Information System (INIS)

Ehling, G.; Hecht, M.; Heusener, A.; Huesler, J.; Gamer, A.O.; Loveren, H. van; Maurer, Th.; Riecke, K.; Ullmann, L.; Ulrich, P.; Vandebriel, R.; Vohr, H.-W.

2005-01-01

The new OECD guideline 429 (skin sensitization: local lymph node assay) is based upon a protocol, which utilises the incorporation of radioactivity into DNA as a measure for cell proliferation in vivo. The guideline also enables the use of alternative endpoints in order to assess draining lymph node (LN) cell proliferation. Here we describe the first round of an inter-laboratory validation of alternative endpoints in the LLNA conducted in seven laboratories. The validation study was managed and supervised by the Swiss Agency for Therapeutic Products, Swissmedic. Statistical analyses of all data were performed by an independent centre at the University of Bern, Department of Statistics. Ear-draining, LN weight and cell count were used to assess proliferation instead of radioactive labeling of lymph node cells. In addition, the acute inflammatory skin reaction was measured by ear swelling and weight of circular biopsies of the ears to identify skin irritating properties of the test items. Hexylcinnamaldehyde (HCA) and three blinded test items were applied to female, 8-10 weeks old NMRI and BALB/c mice. Results were sent via the independent study coordinator to the statistician. The results of this first round showed that the alternative endpoints of the LLNA are sensitive and robust parameters. The use of ear weights added an important parameter assessing the skin irritation potential, which supports the differentiation of pure irritative from contact allergenic potential. There were absolute no discrepancies between the categorisation of the three test substances A-C determined by each single participating laboratories. The results highlighted also that many parameters do have an impact on the strength of the responses. Therefore, such parameters have to be taken into consideration for the categorisation of compounds due to their relative sensitizing potencies

Development of Loop-Mediated Isothermal Amplification Assay for Detection of Entamoeba histolytica▿

Science.gov (United States)

Liang, Shih-Yu; Chan, Yun-Hsien; Hsia, Kan-Tai; Lee, Jing-Lun; Kuo, Ming-Chu; Hwa, Kuo-Yuan; Chan, Chi-Wen; Chiang, Ting-Yi; Chen, Jung-Sheng; Wu, Fang-Tzy; Ji, Dar-Der

2009-01-01

A novel one-step, closed-tube, loop-mediated isothermal amplification (LAMP) assay for detecting Entamoeba histolytica, one of the leading causes of morbidity in developing countries, was developed. The sensitivity of the LAMP assay is 1 parasite per reaction. A total of 130 clinical samples were analyzed, and the results compared with those of conventional nested PCR to validate the practicability of this assay. No DNA was amplified from other diarrheal pathogens, such as other Entamoeba species, bacteria, and viruses. These results indicate that LAMP is a rapid, simple, and valuable diagnostic tool for epidemiological studies of amebiasis. PMID:19321720

Development of a Rickettsia bellii-Specific TaqMan Assay Targeting the Citrate Synthase Gene.

Science.gov (United States)

Hecht, Joy A; Allerdice, Michelle E J; Krawczak, Felipe S; Labruna, Marcelo B; Paddock, Christopher D; Karpathy, Sandor E

2016-11-01

Rickettsia bellii is a rickettsial species of unknown pathogenicity that infects argasid and ixodid ticks throughout the Americas. Many molecular assays used to detect spotted fever group (SFG) Rickettsia species do not detect R. bellii, so that infection with this bacterium may be concealed in tick populations when assays are used that screen specifically for SFG rickettsiae. We describe the development and validation of a R. bellii-specific, quantitative, real-time PCR TaqMan assay that targets a segment of the citrate synthase (gltA) gene. The specificity of this assay was validated against a panel of DNA samples that included 26 species of Rickettsia, Orientia, Ehrlichia, Anaplasma, and Bartonella, five samples of tick and human DNA, and DNA from 20 isolates of R. bellii, including 11 from North America and nine from South America. A R. bellii control plasmid was constructed, and serial dilutions of the plasmid were used to determine the limit of detection of the assay to be one copy per 4 µl of template DNA. This assay can be used to better determine the role of R. bellii in the epidemiology of tick-borne rickettsioses in the Western Hemisphere. Published by Oxford University Press on behalf of Entomological Society of America 2016. This work is written by US Government employees and is in the public domain in the US.