Literatura académica sobre el tema "Sandwich assays"
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Artículos de revistas sobre el tema "Sandwich assays"
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Sanders, Emily C., Alicia M. Santos, Eugene K. Nguyen, Aidan A. Gelston, Sudipta Majumdar y Gregory A. Weiss. "Phage vs. Phage: Direct Selections of Sandwich Binding Pairs". Viruses 15, n.º 3 (22 de marzo de 2023): 807. http://dx.doi.org/10.3390/v15030807.
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The sandwich format immunoassay is generally more sensitive and specific than more common assay formats, including direct, indirect, or competitive. A sandwich assay, however, requires two receptors to bind non-competitively to the target analyte. Typically, pairs of antibodies (Abs) or antibody fragments (Fabs) that are capable of forming a sandwiching with the target are identified through a slow, guess-and-check method with panels of candidate binding partners. Additionally, sandwich assays that are reliant on commercial antibodies can suffer from changes to reagent quality outside the researchers’ control. This report presents a reimagined and simplified phage display selection protocol that directly identifies sandwich binding peptides and Fabs. The approach yielded two sandwich pairs, one peptide–peptide and one Fab–peptide sandwich for the cancer and Parkinson’s disease biomarker DJ-1. Requiring just a few weeks to identify, the sandwich pairs delivered apparent affinity that is comparable to other commercial peptide and antibody sandwiches. The results reported here could expand the availability of sandwich binding partners for a wide range of clinical biomarker assays.
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Zweig, M. H., G. Csako, C. C. Benson, B. D. Weintraub y B. B. Kahn. "Interference by anti-immunoglobulin G antibodies in immunoradiometric assays of thyrotropin involving mouse monoclonal antibodies." Clinical Chemistry 33, n.º 6 (1 de junio de 1987): 840–44. http://dx.doi.org/10.1093/clinchem/33.6.840.
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Abstract "Sandwich"-type assays are subject to positive interference by the patient's "heterophile" antibodies. If present, these bind to the animal immunoglobulins in the assay reagents, forming artefactual sandwiches indistinguishable from those formed with the analyte itself. Immunoglobulins from non-immunized animals, added to the assay reagents, can diminish this effect by blocking the patient's antibodies. Elsewhere, we studied several patients with anti-mouse immunoglobulin activity, whose serum gave spuriously high results for thyrotropin (TSH) concentrations. Here we have studied this phenomenon by adding, to pooled zero-TSH serum, antibodies to mouse, goat, and horse immunoglobulins and then assaying TSH by several other sandwich-type assays involving mouse monoclonal antibodies. Assays not supplemented with blocking immunoglobulins from mice or other animals were more susceptible to this effect. When large amounts of antibody were added, the antibody excess diminished the interference. However, the presence of blocking immunoglobulins could reverse such antibody excess, actually enhancing, instead of diminishing, the positive interference. Users should be aware that blocking immunoglobulins may diminish but not necessarily eliminate this problem with such assays.
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Prudom, Catherine, Jianhua Liu, James Patrie, Bruce D. Gaylinn, Karen E. Foster-Schubert, David E. Cummings, Michael O. Thorner y H. Mario Geysen. "Comparison of Competitive Radioimmunoassays and Two-Site Sandwich Assays for the Measurement and Interpretation of Plasma Ghrelin Levels". Journal of Clinical Endocrinology & Metabolism 95, n.º 5 (1 de mayo de 2010): 2351–58. http://dx.doi.org/10.1210/jc.2009-2407.
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Abstract Context: Ghrelin, an endogenous ligand for the GH secretagogue receptor, is an orexigenic peptide hormone produced primarily by the stomach. Recent studies suggest significant differences in the specificity of currently available ghrelin assays. Objective: The aim of the study was to compare four ghrelin assays (two commercially available and two developed by our group) of differing specificity, each used on the same set of more than 800 plasma samples from a human study. Design: Thirteen volunteers were sampled every 20 min for 6 h after consumption of one of three isocaloric drinks consisting of either 80% fat, 80% carbohydrate, or 80% protein. The samples were assayed by RIA for total and active ghrelin, as well as by sandwich assays for acyl and des-acyl ghrelin. The ghrelin profiles for each individual were smoothed using a statistical algorithm to lessen the effects of pulsatility and noise. Results: The sandwich assays for acyl and des-acyl ghrelin yielded ghrelin values that were lower than those from the corresponding RIAs. The ghrelin profiles after nutrient ingestion were similar, yet key differences among the four assays were apparent; in particular, percentage changes were significantly greater in the sandwich assays. Conclusions: The lower levels and greater relative changes in ghrelin values reported by the sandwich assays are consistent with greater assay specificity. When applied to the nutrient study, the sandwich assays were better able to distinguish the different responses to different nutrients than were the RIAs.
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Kang, J., P. Kaladas, C. Chang, S. Chen, R. Dondero, A. Frank, S. Huhn, P. Lisi, D. Monchnal y J. Nasser. "A highly sensitive immunoenzymometric assay involving "common-capture" particles and membrane filtration." Clinical Chemistry 32, n.º 9 (1 de septiembre de 1986): 1682–86. http://dx.doi.org/10.1093/clinchem/32.9.1682.
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Abstract This highly sensitive immunoenzymometric method involves monoclonal antibodies, a common-capture microsphere, and a rapid, membrane-filtration separation step. The common-capture solid phase is monoclonal anti-fluorescein antibody convalently attached to 6.5 micron-diameter latex particles. In sandwich-type assays for large-molecule analytes, the capture antibody is conjugated with fluorescein isothiocyanate and the probe antibody is conjugated with beta-galactosidase (EC 3.2.1.23). In competitive assays for small analytes, the analyte-beta-galactosidase conjugate competes with the analyte in the clinical samples for the fluoresceinated capture antibody. After simultaneous incubation of the reagents for 2 h, the bound and unbound reagents are separated by filtration through the bottom of each well of a 96-well plate. Substrate (4-methylumbelliferyl-beta-D-galactopyranoside) is then added to the wells, and the rate of product formation is determined kinetically for 12 min. The rate is proportional to the concentration of analyte in the sandwich assays and inversely proportional in the competitive assays. The assay results for choriogonadotropin, thyrotropin, digoxin, and thyroxin show the assay to be sensitive, rapid, and applicable to any size analyte. With this system, several different sandwich and (or) competitive-type assays can be performed simultaneously on the same plate.
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Nielsen, Ulrik B. y Bernhard H. Geierstanger. "Multiplexed sandwich assays in microarray format". Journal of Immunological Methods 290, n.º 1-2 (julio de 2004): 107–20. http://dx.doi.org/10.1016/j.jim.2004.04.012.
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Saviranta, Petri, Ryan Okon, Achim Brinker, Masaki Warashina, Joerg Eppinger y Bernhard H. Geierstanger. "Evaluating Sandwich Immunoassays in Microarray Format in Terms of the Ambient Analyte Regime". Clinical Chemistry 50, n.º 10 (1 de octubre de 2004): 1907–20. http://dx.doi.org/10.1373/clinchem.2004.037929.
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Abstract Background: Conceptionally, antibody microarrays are simply multiplexed sandwich immunoassays in a miniaturized format. However, from the amounts of capture antibodies used, it is not apparent whether such assays are ambient analyte (Ekins. Clin Chem 1998;44:2015–30) or mass-sensing devices (Silzel et al. Clin Chem 1998;44:2036–43). We evaluated multiplexed microarray sandwich assays for 24 mouse serum proteins in these terms within the boundaries of our experimental setup and based on theoretical considerations of the law of mass action. Methods: Capture antibodies for 24 mouse serum proteins were printed on planar microarray substrates. After incubation with mixtures of purified antigens for 1 or 18 h, mixtures of biotinylated detection antibodies were used. High assay sensitivity was achieved by use of resonance-light-scattering particles for signal generation. Titration curves were generated for assay volumes of 20, 40, and 80 μL, and detection limits were calculated and compared. The assays were modeled theoretically based on the amounts of capture antibodies and the assay volumes used. Results: As predicted, experimental variations of the assay volume by up to fourfold did not appreciably affect detection. Even for the most sensitive assay, <2% of the analyte molecules present in the sample were captured and generated signal at the detection limit. However, increasing the sample incubation time from 1 to 18 h on average lowered the detection limit threefold. Conclusions: In our experimental setup, all 24 sandwich microarray assays fulfill the criteria of the “ambient analyte” regime because depletion of analyte molecules from the assay volume is insignificant.
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Neupane, Dharmendra y Keith J. Stine. "Electrochemical Sandwich Assays for Biomarkers Incorporating Aptamers, Antibodies and Nanomaterials for Detection of Specific Protein Biomarkers". Applied Sciences 11, n.º 15 (31 de julio de 2021): 7087. http://dx.doi.org/10.3390/app11157087.
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The development of sensitive and selective assays for protein biomarkers and other biological analytes is important for advancing the fields of clinical diagnostics and bioanalytical chemistry. The potential advantages of using aptamers in electrochemical sandwich assays are being increasingly recognized. These assays may include an aptamer as both capture and detection agent or a combination of an aptamer with a different partner such as an antibody, a lectin or a nanomaterial. The second binding partner in the sandwich structure is typically conjugated to a redox marker, a catalyst or an enzyme that can be used to generate the signal needed for electrochemical detection. Nanoparticles and other nanostructures can be used as the carriers for multiple molecules of the detection partner and thereby increase the signal. Nanostructured surfaces can be used to increase surface area and improve electron transfer. Sensitive electrochemical methods including impedance, differential and square-wave voltammetry and chronocoulometry have been used for electrochemical signal read-out. Impressive results have been achieved using electrochemical sandwich assays in terms of limit of detection and linear range for a growing range of analytes. The recent progress for this type of assay for proteins and other biomarkers is the subject of this review.
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Zhang, Yuan, Gang Xu, Lu Zhang, Jiakai Zhao, Pinpin Ji, Yaning Li, Baoyuan Liu et al. "Development of a double monoclonal antibody–based sandwich enzyme-linked immunosorbent assay for detecting canine distemper virus". Applied Microbiology and Biotechnology 104, n.º 24 (7 de noviembre de 2020): 10725–35. http://dx.doi.org/10.1007/s00253-020-10997-y.
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Abstract Canine distemper virus (CDV) infection causes mass mortality in diverse carnivore species. For effective virus surveillance, rapid and sensitive assays are needed to detect CDV in field samples. In this study, after BABL/c mice were immunized with recombinant CDV-fusion (F) protein, monoclonal antibodies (mAbs) against recombinant CDV-F protein (designated 1A5, 1A6, and 7D5) were produced using traditional hybridoma cell technology. Next, capture antibody (1A6, 800 ng/well) and horseradish peroxidase (HRP)–conjugated detection antibody (HRP-7D5, 1:100, 500 ng/well) were used in a double monoclonal antibody–based sandwich enzyme-linked immunosorbent assay (ELISA) for CDV detection after optimization of both mAb amounts per well using a checkerboard titration test. Based on sandwich ELISA test results for 120 known CDV-negative samples, the cutoff value for a positive result was set to an OD450 nm value ≥ 0.196. As compared with test results obtained from commercial immune colloidal gold test strips, the low limits of detection for the two assays were revealed to be 100 TCID50 per 100 μL. In addition, the sandwich ELISA agreed 100% and 96.4% with commercial immune colloidal gold test strips when testing serum and stool samples. The sandwich ELISA assay provided statistically similar CDV detection. Thus, the sandwich ELISA developed here to detect CDV in fecal and serum samples provided good sensitivity, high specificity, and good reproducibility and should serve as an ideal method for large-scale surveillance of CDV infections in carnivores. Key points • Three CDV mAbs that recognized different epitopes and bound to virion were generated. • The sandwich ELISA based mAbs to detect CDV in fecal and serum samples was developed. • The sandwich ELISA is an ideal method for detecting CDV infections in the field.
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Ezzell, Carol. "Hybritech wins court injunction over sandwich assays". Nature 327, n.º 6117 (mayo de 1987): 5. http://dx.doi.org/10.1038/327005a0.
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Frohnmeyer, Esther, Nadine Tuschel, Tobias Sitz, Cornelia Hermann, Gregor T. Dahl, Florian Schulz, Antje J. Baeumner y Markus Fischer. "Aptamer lateral flow assays for rapid and sensitive detection of cholera toxin". Analyst 144, n.º 5 (2019): 1840–49. http://dx.doi.org/10.1039/c8an01616j.
Texto completoTesis sobre el tema "Sandwich assays"
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Yousef, Jamil. "Development of Sandwich Assays for Potential Protein Biomarkers in Neurodegenerative Diseases". Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278727.
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As the aging population is increasing worldwide, so is the prevalence of neurodegenerativediseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), frontotemporal dementia(FTD) and amyotrophic lateral sclerosis (ALS). Reliable biomarkers able to aid the diagnosis anddifferentiation of these diseases are needed in order to start the right treatment as early as possible.Due to its representative state of the central nervous system, cerebrospinal fluid (CSF) is afavorable sample material for biomarker discovery within neurodegenerative diseases. Alteredprotein levels of this body fluid might serve as a biomarker, but further validation of earlierfindings is needed. The aim of this project was to validate earlier studies suggesting potentialprotein biomarkers in CSF. From a list of 80 potential biomarkers in the CSF of patient samples,eight were chosen to be included in this validation effort. By utilizing a suspension bead array ina sandwich assay setup, 21 antibodies were tested in an initial screening. Antibody pairs that couldmeasure the protein levels in a dilution dependent manner was further optimized before individualpatient samples were analyzed. Sandwich assays targeting the three proteins Amphiphysin(AMPH), Chitotriosidase-1 (CHIT1) and Beta-synuclein (SNCB) were successfully developed andcorrelated to earlier generated data using a suspension bead array with a single binder setup.Therefore, the earlier findings of elevated levels of AMPH and SNCB in AD patients and CHIT1in ALS patients were successfully validated.Prevalensen av neurodegenerativa sjukdomar såsom Alzheimers sjukdom (AD), Parkinsonssjukdom (PD), frontallobsdemens (FTD) och amyotrofisk lateralskleros (ALS) ökar i takt med denåldrande populationen. Pålitliga biomarkörer som kan hjälpa till vid diagnostiseringen av dessasjukdomar behövs för att starta rätt behandling så tidigt som möjligt. Ryggmärgsvätska, enkroppsvätska tillhörande det centrala nervsystemet, kan ge en inblick i det centrala nervsystemetstillstånd. Förändrade proteinnivåer i denna kroppsvätska skulle därför kunna fungera sombiomarkörer. Målet i detta projekt var att validera tidigare föreslagna proteinbiomarkörer iryggmärgsvätska. Utifrån en lista av 80 tidigare analyserade proteiner i ryggmärgsvätska hospatienter, inkluderades åtta proteiner i detta valideringsförsök. En antikroppsbaserad så kalladsandwich assay användes i en suspension bead array för att testa 21 stycken antikroppar i ett initialtscreeningsförsök. Antikroppspar som kunde mäta proteinnivåer på ett spädningsberoende vis i detinitiala screeningsförsöket optimerades vidare innan den utvecklade sandwich assayn användes föratt analysera proteinnivåer i individuella prover. Sandwich assays gentemot Amphiphysin(AMPH), Chitotriosidase-1 (CHIT1) och Beta-synuclein (SNCB) kunde bli framtagna ochkorrelerade gentemot tidigare genererat data från en single binder assay på ett framgångsrikt sätt.Projektet kunde därmed validera tidigare fynd som indikerat förhöjda nivåer av AMPH och SNCBi AD patienter, samt förhöjda nivåer av CHIT1 i ALS patienter.
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Marten, Katharina [Verfasser] y Anil [Akademischer Betreuer] Batra. "Entwicklung eines Sandwich Enzyme-linked Immunosorbent Assays zum Nachweis von humanem α-Synuclein / Katharina Marten ; Betreuer: Anil Batra". Tübingen : Universitätsbibliothek Tübingen, 2017. http://d-nb.info/119954728X/34.
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Jana, Subha. "Biodetection using fluorescence energy transfer from Quantum dot excited whispering gallery modes to fluorescent acceptors". Electronic Thesis or Diss., Université Paris sciences et lettres, 2021. http://www.theses.fr/2021UPSLS081.
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La quantification de biomarqueurs spécifiques est un outil de diagnostic important. Les tests immunologiques standards tels que ELISA nécessitent de nombreuses étapes de lavage et une amplification du signal, en particulier à faible concentration. D'autre part, le transfert d'énergie résonant de type Förster (FRET) a été utilisé pour concevoir des tests biologiques homogènes en une seule étape qui ne nécessitent aucune étape de lavage, où le biomarqueur permet la formation d'un complexe "sandwich" impliquant des anticorps marqués par le donneur et d'autres marqués par l'accepteur. Le FRET du donneur vers l'accepteur fournit alors une signature optique de la formation du complexe, et donc du biomarqueur d'intérêt. Cependant, le FRET, qui est très sensible à la distance donneur-accepteur, ne se produit à un taux significatif que lorsque la distance donneur-accepteur est inférieure à 10 nm; la grande taille de nombreux complexes biologiques limite l'efficacité du transfert d'énergie, empêchant une détection sensible. Je propose ici une nouvelle modalité de transfert d'énergie qui utilise des microcavités optiques en solution. Ensuite, je décris un schéma de biodétection pour détecter un oligonucléotide biomarqueur de cancer en solution.À cette fin, j'ai conçu des structures de microcavité dans lesquelles des nanocristaux fluorescents sont placées à l'intérieur de microsphères diélectriques pour permettre un couplage fort de leur émission de fluorescence avec les modes de résonance de la cavité, appelés modes de galerie (WGM). J'ai étudié les propriétés structurelles et optiques de ces microcavités optiques. J'ai également caractérisé le transfert d'énergie entre ces modes et des nanoparticules acceptrices chargées de colorants présentes dans le champ évanescent, à quelques dizaines de nm au-dessus de la surface des microsphères. J’ai développé un modèle analytique pour caractériser les mécanismes de transfert d'énergie médié par les WGM (WGET). De plus, une comparaison entre WGET et FRET a révélé la supériorité du WGET dans le contexte de la construction de capteurs en termes de sensibilité et de portée de détection. Dans la dernière partie de la thèse, j’ai développé une stratégie pour fonctionnaliser ces microcavités optiques et leur permettre d'interagir avec des analytes cibles tels que l'ADN, l'ARN et les protéines avec une bonne spécificité. Cette stratégie a ensuite été adaptée pour fixer des sondes de capture d'ADN sur les microcavités activées par WGM. En utilisant les microsphères fixées à l'ADN comme donneur optique en combinaison avec des nanoparticules de colorants fonctionnalisées par un ADN complémentaire comme accepteurs optiques, un test de biodétection a été démontré avec succès pour détecter en solution un biomarqueur de cancer appelé survivine. Ce test a démontré une bonne sensibilité envers la cible, et s'est également avéré très spécifique. Le schéma de détection a été démontré dans un microscope confocal, au niveau de microsphères individuelles, puis transposé avec succès dans un instrument beaucoup plus simple tel qu'un spectrofluoromètre qui mesure la fluorescence de l'ensemble de la solution; la signature de la formation d'un complexe sandwich a été détectée efficacement.En conclusion, j'ai démontré que le transfert d'énergie assisté par microcavité présente plusieurs avantages par rapport aux tests FRET ordinaires. Un véritable test de biodétection basé sur le principe du WGET a également été conçu avec succès pour détecter des biomarqueurs du cancer avec une sensibilité et une spécificité élevées. Cette étude ouvre donc de nombreuses possibilités pour concevoir des tests plus performants et plus précis pour détecter diverses entités biologiquesQuantification of specific biomarkers is an important diagnostic tool. Standard immunoassays such as ELISA require extensive washing steps and signal amplification, in particular when the biomarker of interest is only present at very low concentrations. On the other hand, non-radiative Förster resonance energy transfer (FRET) has been used to design one-step homogenous bioassays which do not require any washing steps, where the biomarker enables the formation of a sandwich complex involving donor-labeled and acceptor-labeled antibodies. FRET from the donor to the acceptor then provides an optical signature of the complex formation, hence of the biomarker of interest. However, FRET which is highly sensitive to the donor-acceptor distance, only occurs in a significant rate when the distance between the donor and acceptor is less than 10 nanometers; thus the large size of many biological complexes limits the efficiency of energy transfer, preventing sensitive detection. Here I propose a novel energy transfer modality that uses solution-phase optical microcavities to enhance energy transfer. Following that, I describe a bio-sensing scheme designed to detect a cancer biomarker DNA in solution.To this aim, I have designed microcavity structures in which fluorescent colloidal quantum dots are located inside dielectric polymer microspheres to enable strong coupling of their fluorescence emission with the cavity resonance modes or whispering gallery modes (WGMs) of the microspheres. A detailed study was carried out to comprehend the structural and optical properties of these optical microcavities. I also characterized the energy transfer between these modes and acceptor dye-loaded nanoparticles present in the evanescent field, within a few tens of nanometers above the microsphere surface. An analytical model was constructed to provide insights into the WGM mediated energy transfer (WGET) mechanisms. Moreover, a comparison between WGET and FRET revealed the superiority of WGET in the context of building sensors with improved sensitivity and longer range of detection. In the last part of the thesis, a strategy is discussed in detail to provide biological functionalities to these optical microcavities which would enable them to interact with target analytes such as DNA, RNA, and proteins with high specificity, and moreover to reduce non-specific interactions. This strategy then was adapted to attach DNA capture probes onto the WGM enabled microcavities. Using the DNA attached microspheres as optical donor in combination with probe-DNA functionalized dye nanoparticles as optical acceptors, a biosensing assay has been successfully demonstrated to detect a cancer biomarker DNA called survivin in the solution phase. This assay did not only show good sensitivity towards the target, but also it has proven to be highly specific. The detection scheme has been demonstrated in a sophisticated confocal microscope at the single microsphere level, then successfully translated to a much simpler spectrofluorometer that measures fluorescence from the whole sample solution; the signature of the sandwich complex formation was also effectively detected.In conclusion, I demonstrated that microcavity-assisted energy transfer has several advantages over regular FRET assays. A real bio-sensing assay based on the WGET principle has also been successfully designed to detect cancer biomarkers with high sensitivity and specificity. This study thus opens up many possibilities to design high-performing and more accurate assays to detect varieties of biological entities
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Bregulla, Julie. "Investigation into the fire and racking behaviour of structural sandwich panel walls : a methodology to assess load bearing sandwich panels in fire". Thesis, University of Surrey, 2003. http://epubs.surrey.ac.uk/807/.
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Lima, Jefferson Queiroz. "Contribution to knowledge chemical plant of gender Tephrosia: Chemical investigation and biological assays of Tephrosia egregia Sandwith (Fabaceae)". Universidade Federal do CearÃ, 2010. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=4658.
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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoThe present work describes the chemical study of leaves, stems and roots of the Tephrosia egregia Sandwith (Fabaceae) species, through the analysis of the volatile and nonvolatile constituent of the specie. The determination of the volatile chemical composition of leaves and stems of T. egregia showed the predominance of sesquiterpenes, with some monoterpenes and trisnor-sesquiterpenes. The comparison between identified constituents in the leaves (16; 88.75%) and stems (13; 85.22%) showed a similarity between the samples, although the trisnor-sesquiterpenes geijeren and pregeijeren were the major constituents in both the essential oils. From the chromatographic investigation of the essential oil of leaves, the trisnor-sesquiterpene dictamnol was isolated for the first time in the Tephrosia genus. The chromatographic investigation of the roots of T. egregia yields pongachalcone and praecansone B, of pongaflavone, of 6a,12a-dehydrorotenone and 12a-hydroxyrotenone, the mixture of sitosterol and stigmasterol, and their glucosylated forms, and the maackiain. From its leaves were isolated p-coumaric acid and ferulic acid. This two compounds had been isolated for the first time in the genus. The assays with extracts and isolated substances of T. egregia showed that the studied specie has very important larvicidal activity against Aedes aegypti and allelopathic activity, with best result for the ethanolic extract of the roots. In other hand, the bioassays of antimicrobial activity against of S. aureaus, E. coli, P. aeruginosa, S. choleraesuis and C. albicans, and the nematicidal activity on Meloidogyne incognta not shown significant results.
O presente trabalho descreve o estudo quÃmico das folhas, talos e raÃzes de Tephrosia egregia Sandwith (Fabaceae), atravÃs da anÃlise dos constituintes volÃteis e nÃo volÃteis da espÃcie. A determinaÃÃo da composiÃÃo quÃmica volÃtil das folhas e talos de T. egregia mostrou a predominÃncia de sesquiterpenos, com relatos de monoterpenos e trisnorsesquiterpenos. A comparaÃÃo entre os constituintes identificados nas folhas (16; 88,75%) e talos (13; 85,22%) revelou semelhanÃa entre os mesmos, onde os trisnor-sesquiterpenos geijereno e o pregeijereno foram os constituintes majoritÃrios em ambos os Ãleos essenciais. A partir do fracionamento cromatogrÃfico do Ãleo essencial das folhas foi isolado o trisnorsesquiterpeno dictamnol, relatado pela primeira vez no gÃnero Tephrosia. O estudo dos constituintes nÃo volÃteis foi iniciado a partir da obtenÃÃo dos extratos etanÃlicos das folhas, talos e raÃzes da espÃcie estudada. O fracionamento cromatogrÃfico das raÃzes levou ao isolamento das chalconas pongachalcona e praecansona B, da flavona pongaflavona, dos rotenoides 6a,12a-desidrorotenona e 12a-hidroxirotenona, da mistura dos esterÃides sitosterol e estigmasterol e de suas misturas nas formas glicosiladas e do pterocarpano maackiaina. A partir do extrato acetato de etila do decocto das folhas de T. egregia foram isolados os fenilpropanÃides Ãcido p-cumÃrico e Ãcido ferÃlico, descritos pela primeira vez no gÃnero estudado. Os ensaios de atividades biolÃgicas realizados para os extratos e substÃncias isoladas de T. egregia mostraram que a espÃcie estudada apresenta atividades larvicida sobre Aedes aegypti e alelopÃtica significativas, com destaque para o extrato etanolico das raÃzes (TERES). NÃo foram encontrados resultados significativos para os bioensaios de atividade antimicrobiana sobre cepas de S. aureaus, E. coli, P. aeruginosa, S. choleraesuis e C. albicans, assim como para atividade nematicida sobre Meloidogyne incognita.
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Marassa, Ana Maria. "Identificação de fonte sanguínea em dípteros da Família Culicidae, em áreas de epizootia da febre amarela silvestre". Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/6/6132/tde-20072009-153444/.
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A importância em conhecer o padrão alimentar em mosquitos da Família Culicidae permite esclarecer alguns aspectos relacionados à transmissão de zoonoses e estimar o grau de contato humano-vetor que é fator relevante em estudos epidemiológicos. Com o objetivo de explorar o comportamento alimentar dessa Família, em área epizoótica de febre amarela silvestre, foram coletados exemplares nos municípios de Santo Antônio das Missões e Garruchos, Estado do Rio Grande do Sul. Fêmeas ingurgitadas foram obtidas por aspiração em ambiente de mata, no período de setembro de 2005 a abril de 2007 e identificadas segundo fonte de sangue ingerido através da técnica imunoenzimática ELISA de captura no sistema avidinabiotina. Foram testadas seis fontes de alimento: ave, bovino, eqüino, humano, macaco e rato. Os resultados obtidos mediante a padronização de anticorpos monoclonais possibilitaram demonstrar pela primeira vez o reconhecimento de sangue humano ingerido nesses mosquitos pelo emprego da subclasse IgG1 e comprovar a sensibilidade e especificidade da técnica ELISA de captura. No município de Santo Antônio das Missões, de um total de 190 amostras, 60,9% reagiram para sangue de boi, 23,6% para humano, 9,9% para ave, 1,9% para macaco e 3,7% para combinações de dois hospedeiros. Quanto às amostras referentes ao município de Garruchos, das 158 fêmeas capturadas na área Cachoeirinha pode-se observar reatividade para ave (16%), boi (29,6%), humano (36,8%), cavalo (4%), macaco (0,8%) e combinações de hospedeiros (12,8%), enquanto que para as 149 fêmeas pertencentes à área de São José, detectou-se sangue ingerido de boi em (51,5%), ave e humano (11,5%), macaco (6,2%), cavalo (0,8%) e mistos (18,5%). Aedes scapularis, Aedes crinifer, Culex (Culex) spp., Haemagogus leucocelaenus apresentaram maior número de fêmeas ingurgitadas nos dois municípios. Os resultados obtidos com Aedes scapularis sugerem ecletismo, conforme combinações detectadas em amostras de sangue de diferentes fontes. Haemagogus leucocelaenus apresentou a maior proporção de amostras contendo sangue humano em relação às demais fontes e essa característica traz implicações, por ser espécie incriminada na transmissão e por se tratar de área de ocorrência de epizootias de febre amarela.The knowledge of mosquitoes Culicidae host feeding patterns permits to clarify some aspects related to zoonosis transmission and to estimate the degree of human-vector contact which is relevant in epidemiological studies. Aiming to explore the feeding behavior of these mosquitoes, specimens were collected in the municipalities of Santo Antônio das Missões and Garruchos, Rio Grande do Sul, an epizootic area of sylvatic yellow fever. Engorged females were collected by aspiration from forested areas from September 2005-April 2007 and their blood meals were identified using the avidin-biotin system of immunoenzymatic ELISA capture. Six blood meal sources were tested: bird, cattle, horse, human, monkey and rat. The result achieved with the species-specific IgG1 mAb was unprecedented for mosquito blood meal identification and reinforced the sensibility and specificity of the immunoenzymatic ELISA capture. Of the 190 samples from Santo Antônio das Missões, 60.9% reacted to cattle, 23.6% to human, 9.9% to bird, 1.9% to monkey and 3.7% to mixed blood meals. In Garruchos, of the 158 females collected in Cachoeirinha, 16.0% reacted to bird, 29.6% to cattle, 36.8% to human, 4.0% to horse, 0.8% to monkey and 12.8% to mixed blood, while of the 149 engorged females from São José, blood from cattle accounted for 51.5%, of blood identified, bird and human 11.5%, monkey 6.2%, horse 0.8% and mixed blood 18.5%. Blood engorged females of Aedes scapularis, Aedes crinifer, Culex (Culex) spp., Haemagogus leucocelaenus predominated in the two municipalities. The results obtained with Aedes scapularis suggests its eclecticism, according to the combinations of blood which were detected from different sources. Haemagogus leucocelaenus was found to have the highest proportion of samples containing human blood in comparison with other sources, which has implications, on account of being incriminated in the transmission and also for taking into consideration the outbreaks reported that underline the risk of yellow fever.
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Liebenberg, Annerie. "The development of an enzyme linked immunosorbent assay for the detection of the South African strain(s) of grapevine fanleaf nepovirus". Thesis, Link to the online version, 2008. http://hdl.handle.net/10019/1909.
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Parasar, Parveen. "Determination of the Expression Patterns of Bovine Non-Classical Major Histocompatibility Complex (MHC) Class I Proteins". DigitalCommons@USU, 2013. http://digitalcommons.usu.edu/etd/1999.
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My dissertation hypothesis is that bovine trophoblast cells express cell-surface and secreted non-classical major histocompatibility complex class I (MHC-Ib) proteins which inhibit NK cells and other leukocytes by binding to inhibitory receptors (e.g., LILRB1, LILRB2, KIR2DL4, and/or CD94/NKG2A). Extremely polymorphic and ubiquitously expressed classical MHC class I (MHC-Ia) proteins, which present foreign antigenic peptides to CD8+ T lymphocytes, are involved in acceptance or rejection of tissue grafts. Non-classical MHC class I (MHC-Ib) glycoproteins, such as Human Leukocyte Antigen-G (HLA-G) and murine Qa-2, are important modulators of the maternal immune system during pregnancy. MHC-Ib proteins are: (a) oligomorphic or monomorphic, (b) expressed in specific tissues under specific condtions, and (c) produced as surface and/or soluble isoforms due to alternative splicing. Third trimester-bovine trophoblast cells express both MHC-Ia and MHC-Ib proteins. The MHC-Ib proteins expressed by trophoblast cells during the third trimester of pregnancy are encoded by four bovine leukocyte antigen (BoLA) loci: BoLA-NC1, BoLA-NC2, BoLA-NC3, and BoLA-NC4.
Two MHC-Ia (N*01701 and N*01802) and three MHC-Ib (NC1*00501, NC3*00101 and NC4*00201) proteins showed cell-surface expression in transfection studies performed in murine P815 and human K562 cells. Two additional isoforms, NC1*00401 and NC2*00102, were not detected on the surface of these cells. Nevertheless, both class Ia proteins, N*01701 and N*01802, and five class Ib proteins, NC1*00401, NC1*00501, NC2*00102, NC3*00101, and NC4*00201, were detected in crude cell lysates on Western blots. Precipitation of proteins from culture supernatants showed that cell-surface MHC-Ia (N*01701 and N*01802) and MHC-Ib proteins (NC1*00501, NC3*00101, and NC4*00201) are shed from the surface of these cells into the media. The mechanism of shedding of these proteins is, however, not known. Monoclonal antibodies W6/32, IL-A88, H1A, H6A, H11A, H58A, and PT-85A recognized surface MHC-I isoforms with varying affinity. We were able to develop a sandwich enzyme-linked immunosorbent assay (ELISA) using either H1A or IL-A88 antibody as the capture antibody and the W6/32 antibody for detection. We produced monoclonal antibodies against cattle NC1*00501 and NC3*00101 proteins. One monoclonal antibody generated against BoLA-NC3*00101 was highly specific. Unfortunately, due to failure to clone the NC3*00101- hybridoma, we no longer have an infinite source of this monoclonal antibody for NC3*00101. We eluted peptides from NC3*00101-transfected MHC-null K562 cells and identified peptides using liquid chromatography-mass spectrum (LC-MS) analysis. Analysis of peptide binding data using the SAS Proc mixed statistical program, suggested that the peptide EVTNQLVVL is a potential peptide ligand, which can be used to make tetramers for enumeration of antigen-specific leukocytes.
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León, janampa Nancy. "Development of a test associated with magnetic nanoparticles for the diagnosis of tuberculosis". Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0272.
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Mycobacterium tuberculosis provoque l'une des maladies qui présentent le taux de mortalité et de morbidité le plus élevé des Amériques et du monde. Dans les pays en développement, le diagnostic de la tuberculose (TB) repose sur la microscopie des frottis et des cultures bactériologiques. La première méthode a une faible sensibilité et la seconde met plusieurs semaines à atteindre un diagnostic de confirmation. L'absence de diagnostic rapide compromet les efforts de lutte contre la tuberculose, favorisant ainsi sa transmission à la population vulnérable. Actuellement, les nanoparticules magnétiques (MNP) fonctionnalisées par des biomolécules sont utilisées en biomédecine, en raison de leurs propriétés magnétiques, électriques et optiques. De cette manière, en appliquant des champs magnétiques externes, les MNP bio-fonctionnalisées sont utilisées pour détecter et concentrer les cellules et les biomolécules à partir d'échantillons biologiques.Dans ce travail, nous présentons la synthèse, la caractérisation et la bio-fonctionnalisation de nanoparticules magnétiques afin de développer un test ELISA en sandwich associé aux MNP, afin de détecter les antigènes de M. tuberculosis. À cette fin, des nanoparticules magnétiques ont été synthétisées par une méthode de co-précipitation. La surface des MNP a été amino-silanisée (MNP@Si@NH2) et caractérisée par des méthodes physico-chimiques.Les antigènes MTB évalués dans cette étude étaient: Hsp16.3, CFP10, ESAT6, MTC28, MPT64, protéine de 38 kDa, Ag85B et MoeX. Le clonage et l'expression de protéines recombinantes ont été réalisés dans le système de E. coli BL21 (DE3) pLysS. Des anticorps polyclonaux ont été produits chez des lapins Nouvelle-Zélande et des souris BALB/C, préalablement immunisés avec des antigènes recombinants purifiés. Des anticorps spécifiques (ab) ont été immobilisés sur les surfaces des MNP amino-silanisées. Les MNP@Si@ab ont été associées dans un test ELISA sandwich colorimétrique pour capturer et détecter les antigènes natifs du MTB à partir d’échantillons d’expectorations.La XRD, la spectroscopie Mössbauer, le potentiel zêta, la TEM et le FTIR ont validé l'obtention des MNP montrant un diamètre de cristal de diffraction de ~ 12,5 nm (10,48 ± 2,56 nm), une charge nette superficielle de +23,57 ± 2,87 mV, des profils caractéristiques de magnétite et une structure sphérique. De plus, une saturation en aimantation de 37,06 emu.g-1 a été observée. Pour la fonctionnalisation des surfaces de nanoparticules avec des anticorps, une méthode via l'utilisation d'ester activé (agent de couplage EDC/NHS) a été utilisée pour la formation de liaisons peptidiques. Des paramètres tels que le temps d'incubation, la concentration des agents de couplage et le niveau de saturation de surface des MNP amines silanisées (MNP@Si@NH2) ont déjà été standardisés.Enfin, des anticorps fonctionnalisés sur des MNP ont été utilisés pour capturer et détecter les antigènes recombinants et natifs de M. tuberculosis dans un test sandwich ELISA-MNP@Si@ab (dans un temps de réaction <4 h). Les antigènes ESAT6 et CFP10 ont été mieux différenciés dans les expectorations des patients atteints de tuberculose (fold value ~ 1,8). L'utilisation de MNP@Si@ab a amélioré la détection des antigènes du MTB dans des échantillons biologiques. Nos résultats sont encourageants, mais des évaluations supplémentaires sont nécessaire telles que la détermination de réactions croisées avec des échantillons d'expectorations provenant de patients atteints d'autres infections, la réalisation du test avec les expectorations fraîches de patients tuberculeux et la détermination de la sensibilité et de la spécificité de la méthodeMycobacterium tuberculosis causes one of the diseases with the highest mortality and morbidity rate in the Americas and around the world. In developing countries, the diagnosis of tuberculosis (TB) is based on smear microscopy and bacteriological cultures. The first method has low sensitivity, and the second take several weeks to reach a confirmatory diagnosis. The lack of a rapid diagnosis compromises the efforts to control TB, favoring its transmission to the susceptible population. Currently, magnetic nanoparticles (MNPs) functionalized with biomolecules have been used in biomedicine, due the magnetic, electrical and optical properties. In this way, applying external magnetic fields, bio-functionalized MNPs is used to detect and concentrate cells and biomolecules from biological samples.In this work we present the synthesis, characterization and bio-functionalization of magnetic nanoparticles, to develop a sandwich ELISA assay associated to MNPs to detect antigens from M. tuberculosis. For this purpose, magnetic nanoparticles were synthesized by co-precipitation method. The MNP surface was amine-silanized (MNP@Si@NH2) and characterized by physical-chemical methods.The MTB antigens evaluated in this study were: Hsp16.3, CFP10, ESAT6, MTC28, MPT64, 38 kDa protein, Ag85B and MoeX. Cloning ad expression of recombinant proteins were made in E. coli BL21 (DE3) pLysS system. Polyclonal antibodies were produced in New Zealand rabbits and BALB/C mice, previously immunized with purified recombinant antigens. Specific antibodies (ab) were immobilized in the amine-silanized MNP surfaces. The MNP@Si@ab were associated in a colorimetric sandwich ELISA assay to capture and detect native MTB antigens from sputum samples.The XRD, Mössbauer spectroscopy, zeta potential, TEM and FTIR demonstrated the successful preparation of the MNPs showing a diffraction crystal diameter of ~12.5 nm (10.48 ± 2.56 nm), superficial net charge of ᶎ: +23.57 ± 2.87 mV, characteristic patterns of magnetite and a spherical structure. Additionally, a magnetization saturation of 37.06 emu.g-1 was observed. For the functionalization of nanoparticle surfaces with antibodies, active ester method (coupling agent EDC/NHS) were used for peptide bond formation. Parameters such as time of incubation, concentration of coupling agents and surface saturation level of amine-silanized MNPs (MNP@Si@NH2), were previously standardized.Finally, antibody functionalized on MNPs were used to capture and detect recombinant and native M. tuberculosis antigens in an ELISA-MNP@Si@ab sandwich test (in a reaction time <4 h). The ESAT6 and CFP10 antigens were better discriminated in sputum pooles from patients with TB (fold value ~ 1.8). The use of MNP@Si@ab improved the detection of MTB antigens in biological samples. Our results are encouraging, but the essay requires additional evaluations such as determining cross-reactions with sputum samples from patients with other infections, performing the test with fresh sputum of TB patients, and determining the sensitivity and specificity of the method
Mycobacterium tuberculosis causa una de las enfermedades con la tasa más alta de mortalidad y morbilidad en las Américas y en todo el mundo. En países en vías de desarrollo, el diagnóstico de tuberculosis (TB) se basa en microscopía de frotis y cultivos bacteriológicos. El primer método tiene baja sensibilidad y el segundo toma varias semanas para llegar a un diagnóstico confirmatorio. La falta de un diagnóstico rápido compromete los esfuerzos para controlar la TB, lo que favorece su transmisión a la población susceptible. Actualmente, las nanopartículas magnéticas (MNP) funcionalizadas con biomoléculas se han utilizado en biomedicina, debido a las propiedades magnéticas, eléctricas y ópticas. De esta manera, aplicando campos magnéticos externos, se utilizan MNP bio-funcionalizadas para detectar y concentrar células y biomoléculas a partir de muestras biológicas. En este trabajo presentamos la síntesis, caracterización y bio-funcionalización de las nanopartículas magnéticas para desarrollar un ensayo ELISA sándwich usando MNPs para detectar antígenos de M. tuberculosis. Para este propósito, las nanopartículas magnéticas fueron sintetizadas por el método de co-precipitación. La superficie de MNP fue amino-silanizada (MNP@Si@NH2) y se caracterizada por métodos físico y químicos. Los antígenos de MTB evaluados en este estudio fueron: Hsp16.3, CFP10, ESAT6, MTC28, MPT64, proteína de 38 kDa, Ag85B y MoeX. La clonación y la expresión de las proteínas recombinantes se realizaron en el sistema de E. coli BL21 (DE3) pLysS. Se produjeron anticuerpos policlonales en conejos de Nueva Zelanda y ratones BALB/C, inmunizados previamente con antígenos recombinantes purificados. Se inmovilizaron anticuerpos específicos (ab) en las superficies de MNP amino-silanizadas (MNP@Si@ab). El MNP@Si@ab fue utilizado en un ensayo ELISA sándwich colorimétrico para capturar y detectar antígenos de MTB nativos en muestras de esputo. La XRD, espectroscopia de Mössbauer, la potencial zeta, TEM y FTIR demostraron la preparación exitosa de los MNP, el cual mostró un diámetro de difracción del cristal de ~ 12.5 nm (10.48 ± 2.56 nm), carga neta superficial de ᶎ: +23.57 ± 2.87 mV, patrones característicos de magnetita y una estructura esférica. Además, una saturación de magnetización de 37.06 emu.g-1 fue observada. Para la funcionalización de superficies de nanopartículas con anticuerpos, se utilizó el método del éster activo para la formación de enlaces peptídicos. Parámetros tales como el tiempo de incubación, la concentración de los agentes de acoplamiento y el nivel de saturación de la superficie de las MNPs aminosilanizadas (MNP@Si@NH2) fueron estandarizadas. Finalmente, se usaron MNP funcionalizados con anticuerpos para capturar y detectar antígenos nativos y recombinantes de M. tuberculosis en una prueba sándwich de ELISA-MNP@Si@ab en un tiempo de reacción <4 h. Los antígenos ESAT6 y CFP10 se discriminaron mejor en las muestras de esputo de los pacientes con TB (fold value ~ 1,8). El uso de MNP@Si@ab mejoró la detección de antígenos de MTB en muestras biológicas con respecto a un sELISA convencional. Nuestros resultados son alentadores, pero el ensayo requiere evaluaciones adicionales, como determinar reacciones cruzadas con muestras de esputo de pacientes con otras infecciones, realizar la prueba con esputo frescos de pacientes con TB y determinar la sensibilidad y especificidad clînica del método
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Pearson, Brooke. "Development of a SERS Sandwich Assay Platform for Rapid Detection of Bacteria". 2017. https://scholarworks.umass.edu/masters_theses_2/529.
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The increased incidence of food pathogen outbreaks placed a new emphasis on the requirement of a rapid, sensitive, and reliable detection method for pathogens in food samples. Surface-enhanced Raman spectroscopy (SERS) is a technique that tremendously enhances the weak Raman scattering of an analyte by using a metallic nano-substrate. Herein, we developed an innovative SERS sandwich assay platform which is based on 3-mercaptophenylboronic acid (3-MPBA) or aptamer as a capturer, and 3-MPBA and silver nanoparticles (AgNPs) as the reporter for non-selective and selective detection of bacteria. Both optical and chemical (SERS mapping) imaging were used as mechanisms for bacterial detection and quantification. Using Salmonella enterica and Listeria monocytogenes as the model bacteria, we have identified a unique bacterial SERS signal upon the interaction between the captured bacteria, 3-MBPA and AgNPs, which was used as the base for reliable detection of bacteria using SERS mapping. The non-specific assay also possesses unique optical properties allowing for the enhanced visualization of bacteria at low microscope magnifications (10 and 20x objective lenses). Using 3-MBPA owe achieved sensitive detection and quantification of as low as 102 CFU/mL and a capture efficiency of 92.1% for nonselective detection of Salmonella. The capability of the assay method to detect specific bacteria using an aptamer was also demonstrated. Besides the SERS applications of this assay, it was discovered that the 3-MPBA coated gold chip developed for this assay enhances the visualization of bacteria under a light microscope allowing for facile and rapid detection and quantification. In anticipation for industrial applications, sample preparation methods and strategies were developed for simple and carbohydrate food matrices.
Libros sobre el tema "Sandwich assays"
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Xia, Fan, Xiaojin Zhang, Xiaoding Lou y Quan Yuan, eds. Biosensors Based on Sandwich Assays. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7835-4.
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Xia, Fan, Quan Yuan, Xiaojin Zhang y Xiaoding Lou. Biosensors Based on Sandwich Assays. Springer, 2018.
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Biosensors Based on Sandwich Assays. Springer, 2019.
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Xia, Fan, Xiaojin Zhang y Xiaoding Lou. Biosensors Based on Sandwich Assays. Springer, 2018.
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Jacobs, Samantha E., Catherine B. Small y Thomas J. Walsh. Fungal diseases of the respiratory tract. Editado por Christopher C. Kibbler, Richard Barton, Neil A. R. Gow, Susan Howell, Donna M. MacCallum y Rohini J. Manuel. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780198755388.003.0030.
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Fungal respiratory infections are important causes of morbidity and mortality in immunocompromised patients. Invasive aspergillosis remains the most common invasive fungal infection whereas other filamentous fungi, such as Fusarium spp., Mucorales, and Scedosporium spp., are increasing in frequency, particularly in neutropenic hosts. Endemic mycoses, including those due to Histoplasma capsulatum, Coccidioides spp., and Talaromyces marneffei, are increasingly prevalent in patients with cell-mediated immunodeficiencies in respective geographic regions. Culture remains the gold standard of diagnosis but has limited sensitivity and often requires invasive procedures. Non-invasive diagnostic tests, including the serum sandwich enzyme immunoassay for the detection of galactomannan, the (1→3)-β-D-glucan assay, and molecular amplification methods have been developed to facilitate early and accurate diagnosis. Successful therapy depends upon early initiation of antifungal agents and reversal of immunosuppression. Lipid formulations of amphotericin B and newer generation triazoles including voriconazole, posaconazole, and isavuconazole have expanded the ability to treat multi-drug resistant pathogens more effectively and with less toxicity.
Capítulos de libros sobre el tema "Sandwich assays"
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Zhang, Xiaojin y Fan Xia. "Biosensors Based on Supersandwich Assays". En Biosensors Based on Sandwich Assays, 199–216. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7835-4_12.
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Zhang, Xiaojin y Fan Xia. "Introduction". En Biosensors Based on Sandwich Assays, 1–13. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7835-4_1.
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Dai, Yu, Xiaojin Zhang y Fan Xia. "Sandwich Assays for Small Molecule and Ion Detection". En Biosensors Based on Sandwich Assays, 167–82. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7835-4_10.
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Li, Shaoguang, Hui Li y Fan Xia. "Sandwich Assay for Pathogen and Cells Detection". En Biosensors Based on Sandwich Assays, 183–97. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7835-4_11.
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Xia, Fan, Xiaojin Zhang, Xiaoding Lou y Quan Yuan. "Erratum to: Biosensors Based on Sandwich Assays". En Biosensors Based on Sandwich Assays, E1. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7835-4_13.
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Yi, Xiaoqing, Rui Liu, Xiaoding Lou y Fan Xia. "Colorimetric Sandwich Assays for Protein Detection". En Biosensors Based on Sandwich Assays, 15–27. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7835-4_2.
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Huang, Fujian y Fan Xia. "Fluorescence Sandwich Assays for Protein Detection". En Biosensors Based on Sandwich Assays, 29–45. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7835-4_3.
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Li, Hui, Shaoguang Li y Fan Xia. "Electrochemical Sandwich Assays for Protein Detection". En Biosensors Based on Sandwich Assays, 47–68. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7835-4_4.
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Zhan, Shenshan, Xiaoding Lou, Pei Zhou y Fan Xia. "Sandwich Assays Based on SPR, SERS, GMR, QCM, Microcantilever, SAW, and RRS Techniques for Protein Detection". En Biosensors Based on Sandwich Assays, 69–91. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7835-4_5.
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Hu, Xiaoxia y Quan Yuan. "Colorimetric Sandwich Assays for Nucleic Acid Detection". En Biosensors Based on Sandwich Assays, 93–106. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7835-4_6.
Texto completoActas de conferencias sobre el tema "Sandwich assays"
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Metwali, Nervana, Kimberly A. Hoppe y Peter S. Thorne. "Comparison Between Two Sandwich Enzyme-Linked Immunosorbent Assays (ELISAs) For Analysis Of Airborne ²-(13)-Glucans". En American Thoracic Society 2010 International Conference, May 14-19, 2010 • New Orleans. American Thoracic Society, 2010. http://dx.doi.org/10.1164/ajrccm-conference.2010.181.1_meetingabstracts.a4645.
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Pereira, Clayrton de Barros, Yuri Felix Pedra y Renata Dellalibera-Joviliano. "Profile of IL-1 beta, INF-gamma, IL-4 and IL-17 in patients with COVID-19". En III SEVEN INTERNATIONAL MULTIDISCIPLINARY CONGRESS. Seven Congress, 2023. http://dx.doi.org/10.56238/seveniiimulti2023-175.
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The immune response to SARS-CoV-2 is mediated by several soluble chemotactic factors, including cytokines whose levels vary at different stages and types of infections. Clinical evidence shows that "cytokine storm," in which the body has high levels of several pro-inflammatory cytokines, is common in several patients with severe COVID-19. Thus, the aim of this study was to evaluate the inflammatory response mediated by the cytokines IL-1 Beta, INF-Gama, IL-4 and IL-17 in patients with COVID. Sandwich-type immunoenzymatic assays (ELISA sandwich) were performed to determine the serum cytokine concentration of a group of 11 patients with RT-PCR confirmed diagnoses compared to a control group (n=11). The samples were evaluated in duplicate and the statistical analyses of the results considered the measures of central tendency with the mean (Md). Thus, we found the results related to the different cytokines: IL-beta (patient = 138 pg/mL; control = 50 pg/mL); Interferon-gamma (patient= 104.25 pg/mL; control= 55 pg/mL); IL-4 (patient= 92.25 pg/mL; control 44 pg/mL); IL-17 (patient= 94.5 pg/mL; control 57 pg/mL). Understanding the variation in the levels of these mediators during pathology, through the analysis of the partial results of the project, is essential to elucidate the profile of the inflammatory response of patients with COVID-19.
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Koppert, P. W., E. Hoegee-de Nobel y W. Nieuwenhuizen. "A NEW QUANTITATIVE ENZYME-IMMUNOASSAY FOR FIBRIN DEGRADATION PRODUCTS (FbDP) IN PLASMA, BASED ON MONOCLONAL ANTIBODIES". En XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643128.
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We have developed a sandwich-type enzyme immunoassay (EIA) for the quantitation of fibrin degradation products (FbDP) in plasma with a time-to-result of only 45 minutes. The assay is based on the combination of the specificities of two monoclonal antibodies (FDP-14 and DD-13), developed in our institute. FDP-14, the catching antibody, binds both fibrinogen degradation products (FbgDP) and FbDP. It has its epitope in the E-domain of the fibrinogen molecule on the BB-chain between amino acids 54-118 (Blood 68, 437, 1986). Antibody DD-13 was raised using D-dimer as antigen and was used as a tagging antibody, conjugated with horse-radish peroxidase.A strong positive reaction is obtained with a whole blood clot lysate (lysis induced by tissue-type plasminogen activator) which is used as a standard.The EIA does not detect FbgDP i.e. purified fragments X, Y, D:E complexes or FbgDP in plasma treated in vitro with streptokinase. This indicates that the assay is specific for fibrin degradation products.We have successfully applied this assay to the plasma of patients with a variety of diseases. In combination with the assays previously developed by us for FbgDP (Thromb. Haemostas. 1987, in press) and for the total amount (TDP) of FbgDP + FbDP in plasma (J. Lab. Clin. Med. 1987, in press), we are now able to study the composition of TDP in terms of FbgDP and FbDP in patients.
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Bleyl, H. "TWO-SIDE IMMUNOASSAYS OF ENZYME-INHIBITOR COMPLEXES FOR THE DIAGNOSIS OF THROMBOPHILIC STATES". En XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643113.
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The diagnosis of prethrombotic states requires methods which detect products of intravasal activation of the coagulation cascade.Two-side immunoassays for antithrombin complexes with clotting factors were developed (IXi-AT, Xi-AT, IIi- AT). These sandwich assays permit the diagnosis of hypercoagulability in the presence or absence of heparin. The biological half live time of the thrombin-antithrombin-complex was found to be about 15 min. Healthy young men 20-25 years old (n=30) have a thrombin-antithrombin-complex concentration of 0.4 ± 0.2 mU/ml thrombin equivalent (S 2238). Patients with acute myocardial infarction (n=40) showed at the time of admission to the hospital up to 10-fold (n=14), up to 100-fold (n=13) more than 100-fold (n=13) elevated thrombin-antithrombin-complex concentrations. Patients with gastrointestinal cancer showed sometime excessive elevated enzyme-inhibitor complexes.No correlation was found between thromboplastine time (Quick) and complex concentration in patients under anticoagulant therapy with dicumarole. In patients under dialysis as well as in patients under open heart surgery with extracorporal circulation, the biocompatibility can be monitored by inhibitor complex measurement.
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Bloom, J. W., J. A. Berkner y G. Mitra. "FACTOR VIII:C, 80 KD AND 90-210 KD POLYPEPTIDE QUANTITATION BY SLISA". En XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644042.
Texto completoResumen
Purified Factor VIII:c is generally found proteolyzed into nultiple polypeptides. An 80 kD polypeptide appears to form a metal-linked complex with each of a series of 90-210 kD polypeptides and separation of these complexes results in loss af Factor VIII:c activity. To quantitate total Factor VIII:c content - active and inactive - three sandwich ELISA's were developed using an immunopurified polyclonal antibody as the capture antibody. This antibody was shown by a Western blot of Factor VIII:c to interact with all the 80-210 kD polypeptides. Utilizing biotinylated polyclonal antibody, an ELISA was developed that detected both the purified carboxy terminal (80 kD) and amino terminal (90-210 kD) polypeptides. Thrombin treated 80 kD polypeptide and Factor VIII:c were also detected by this ELISA. A second ELISA was developed with a biotinylated monoclonal, designated C8, that detected purified 90-210 kD polypeptides, but not the 80 kD polypeptide. A third ELISA was developed with a biotinylated monoclonal, designated C7F7, that detected only the purified 80 kD functional subunit of Factor VIII:c. Thrombin treated 80 kD polypeptide and Factor VIII:c were not detected by this ELISA. These three ELISA methods combined allow estimates of amounts of denatured or thrombin degraded Factor VIII:c to be determined, information not obtainable by the coagulation activity assays.
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Wachtfogel, Yanina T., Peter C. Harpel, L. Henry Edmunds y Robert W. Colman. "FORMATION OF Cl -Cl INHIBITOR AND KALLIKREIN-Cl INHIBITOR COMPLEXES DURING CARDIOPULMONARY BYPASS". En XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642900.
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Cardiopulmonary bypass prolongs bleeding time and increases postoperative blood loss. Contact of blood with synthetic surfaces during extracorporeal circulation leads to major qualitative and quantitative alterations in both platelets and neutrophils. Activation of platelets results in thrombocytopenia, decreased sensitivity of platelets to aggregating agents, decreased alpha2-adrenergic and fibrinogen receptors, secretion of thromboxane B2, and depletion of alpha-granule protein contents. Neutrophils,under similar conditions, have also been shown to release their specific granule protein, lactoferrin, and their azurophilic granule enzyme, elastase.We now investigate whether the classical complement, contact, or fibrinolytic pathways have been activated as potential sources of neutrophil agonists. Employing enzyme-linked immunosorbent “sandwich” assays specific for Cl -Cl inhibitor and kalli-krein-Cl inhibitor complexes respectively, we found that plasma levels of both of these formed complexes increased 2fold after clinical cardiopulmonary bypass was completed and reverted to baseline within 24 hours post-operatively. Since these complexes are cleared iji vivo, we investigated their plasma levels during jLn vitro simulated extracorporeal circulation. Over a period of 2 hours, Cl -Cl inhibitor complexes rose from a baseline of 2 + InM to 21 + 2 nM and kalli-krein-Cl inhibitor complexes rose from 2+1 nM to 25 + 5 nM. However, there was no evidence of either in vivo or vitro plasmin-alpha plasmin inhibitor complex formation. These results indicate that activation of the classical pathway of complement and the contact system in plasma may be associated with neutrophil activation seen during clinical cardiopulmonary bypass.
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I-Jane Chen y Ian M. White. "Sandwich structure electrochemical assay for single stranded DNA detection". En 2010 Ninth IEEE Sensors Conference (SENSORS 2010). IEEE, 2010. http://dx.doi.org/10.1109/icsens.2010.5690168.
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Baldini, Francesco, Luca Bolzoni, Ambra Giannetti, Melanie Kess, Petra M. Kraemer, Elisabeth Kremmer, Giampiero Porro, Folco Senesi y Cosimo Trono. "A sandwich assay for procalcitonin detection for POCT applications". En SPIE BiOS: Biomedical Optics, editado por Anita Mahadevan-Jansen, Tuan Vo-Dinh y Warren S. Grundfest. SPIE, 2009. http://dx.doi.org/10.1117/12.810265.
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Sumner, James J., Kevin W. Plaxco, Carl D. Meinhart y Hyongsok Soh. "Development of an electrochemical biosensor without a sandwich assay". En Optics East 2005, editado por Brian M. Cullum y J. Chance Carter. SPIE, 2005. http://dx.doi.org/10.1117/12.630748.
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Lacharme, F., C. Vandevyver y M. A. M. Gijs. "Magnetic beads retention device for on-chip sandwich immuno-assay". En 2008 IEEE 21st International Conference on Micro Electro Mechanical Systems. IEEE, 2008. http://dx.doi.org/10.1109/memsys.2008.4443623.
Texto completoInformes sobre el tema "Sandwich assays"
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Survey of health and social care setting food businesses on implementation of the FSA Listeriosis Guidance. Food Standards Agency, mayo de 2023. http://dx.doi.org/10.46756/sci.fsa.djg946.
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Food safety is a crucial component of protecting the wellbeing of those in the care of health and social care organisations. Incidents, such as the 2019 listeriosis outbreak associated with pre-packed sandwiches supplied to hospitals in England, from which seven patients died of listeriosis, underline the risk of the disease and the serious consequences that a breach in standards can have. Vulnerable consumers - whose immune systems are weakened in some way - are particularly susceptible to listeriosis and the disease has a high hospitalisation and fatality rate, compared to infections with other bacterial pathogens. The bacterium which causes listeriosis, Listeria monocytogenes, is acutely challenging to control as it has the potential to grow at low temperatures and can survive freezing. As such, L. monocytogenes must be controlled in any health or social care (HSC) organisation that provides chilled ready-to-eat food for vulnerable groups. The Food Standards Agency (FSA) guidance on ‘Reducing the risk of vulnerable groups contracting listeriosis (Opens in a new window)’ concentrates on preventing the spread of listeriosis, from preparation to consumption, in chilled ready-to-eat food. The review set up following the 2019 listeriosis outbreak - the Independent Review of NHS Hospital Food (Opens in a new window), contained recommendations on food safety for NHS trusts to take on board. The FSA also committed to assess its own guidance in response to the 2019 outbreak. Social research was commissioned as part of the FSA’s response. This report covers findings from 39 respondents within NHS Trusts and 445 from Health and Social Care (HSC) (non- NHS Trust) settings, such as nursing homes, home care service providers and hospices, in England, Wales and Northern Ireland. The research objectives for the surveys of health and social care settings and NHS Trusts were to: Measure awareness of the FSA guidance on listeriosis Find out how well the FSA guidance on listeriosis is implemented Understand barriers to implementing the guidance in full Understand good practice in implementing the guidance Understand HSC stakeholders’ perceptions of the effectiveness and suitability of the guidance