Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xvi, 216 p.; also includes graphics (some col.). Includes bibliographical references (p. 180-216). Available online via OhioLINK's ETD Center

Tierärztl. Hochsch., Diss., 2004--Hannover.

Tierärztl. Hochsch., Diss., 2004--Hannover.

Freie Universiẗat, Diss., 2005--Berlin. / Dateiformat: zip, Dateien im PDF-Format. Erscheinungsjahr an der Haupttitelstelle: 2005.

Made available in DSpace on 2014-08-13T14:50:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-11-14Bitstream added on 2014-08-13T18:00:47Z : No. of bitstreams: 1 000753373.pdf: 543622 bytes, checksum: 568807a679f23679d4c54335db59a4d0 (MD5) / O reaparecimento de manifestações clínicas após tratamento eficaz, neste texto identificado como recaída, tem sido pouco avaliado. Assim, foram estudados os casos de recaída observados em 400 pacientes, 93 com a forma aguda/subaguda (FA) e 307 com a crônica (FC), que já tinham apresentado cura aparente, isto é, com cura clínica, normalização da velocidade de hemossedimentação e cura sorológica – caracterizada pela presença de teste negativo à imunodifusão dupla em gel de agar por dois anos. Vinte e um (5,2%) desses pacientes apresentaram recaídas da doença. Três (14,3%) eram do sexo feminino e 18 (85,7%) do masculino, com razão de masculinidade de 6:1. Dos 21 pacientes com recaída, 15 (4,8%) apresentavam a FC e 6 (6,4%) a FA (p>0,05). As reativações ocorreram de 46 a 296 meses após introdução do tratamento (Md=96) e de 4 a 267 meses (Md= 60) após sua suspensão. As formas clínicas não diferiram quanto aos tempos decorridos até a reativação. O diagnóstico sorológico de recaída pela IDD foi feito em apenas 45% dos casos, o que levou à avaliação de outros testes para esse fim. Assim, foi realizado o enzimaimunoensaio (ELISA) e o immunoblotting (IB). A sensibilidade da IDD e do ELISA / 0,710 foi 76,1% em amostras de soro obtidos no pré-tratamento (p=0,25). No diagnóstico de recaída, a sensibilidade da IDD foi menor que no pré-tratamento (80% vs 45%; p=0,017), enquanto o ELISA / 0,710 foi igual (80% vs 65%;p=0,125). A sensibilidade do IB para diagnóstico de recaída foi de 12,5% na identificação da gp70 e 43,8% na da gp43 (p<0,05). A avaliação da acurácia do teste ELISA revelou sensibilidade de 96%, especificidade de 95%, valor preditivo positivo de 95%, valor preditivo negativo de 96% e acurácia de 95,5% quando o cut-off utilizado foi a densidade óptica de 0,710, obtido em função da construção da receiver operator characteristc – ROC, para um intervalo de confiança ... / The reappearance of clinical manifestations after efficacious treatment, here identified as relapse, has been rarely evaluated. Thus, the cases of relapse observed in a cohort of 400 patients, 93 with acute/subacute form (AF) and 307 with chronic form (CF) were studied. They had already reached apparent cure, characterized as clinical cure, normalization of the erythrocyte sedimentation rate and serological cure, with a negative double agar gel immunodiffusion test (DID) for two years after antifungal discontinuation. Twenty-one (5.2%) of these patients had relapses. Three (14.3%) were female and 18 (85.7%) were male, with a male:female ratio of 6:1. Of the 21 relapsed patients, 15 (4.8%) presented the CF and 6 (6.4%) the AF (p>0.05). The relapse occurred 46-296 months after introduction of the treatment (Md=8 yrs) and from 4 to 267 months (Md=5 yrs) after withdrawal. Clinical forms did not differ regarding to the time elapsed until relapse. DID was positive in only 45% of the relapsed cases, which led to the evaluation of other tests to diagnose this condition. Thus, the enzyme-linked immunosorbent assay (ELISA) was standardized and the cut off was determined using the curve receiver operator characteristic – ROC and confidence intervals of 95% and 99%, showing optical densities of 0.710 and 0.850, respectively. Then, serological evaluation was performed using ELISA/0.710 and ELISA/0.850, and immunoblotting identifying gp43 (IBgp43) and gp70 (IBgp70). ELISA 0.710 and DID showed the same sensitivity, 76.1%, in serum samples obtained before treatment (p=0.25). DID sensitivity was lower at relapse than before the initial treatment (45% vs 80%; p=0.017), whereas ELISA/0,710 was the same (65% vs 80%; p=0.125). IBgp70 showed a 12.5% and IBgp43 a 43.8% sensitivity for diagnosing relapse (p<0.05). ELISA/0.710 showed a 96% sensitivity, 95% specificity, 95% positive predictive value, 96% negative ...

Orientador: Wilma Aparecida Starke Buzetti / Banca: Edson Guilherme Vieira / Banca: Willian Marinho Dourado Coelho / Resumo: A leishmaniose visceral (LV), doença causada pelo protozoário Leishmania infantum e transmitida pelo flebotomíneo Lutzomyia longipalpis, é considerada um problema de saúde pública no Brasil. O objetivo deste trabalho foi realizar um estudo epidemiológico sobre a ocorrência da LV em cães e gatos e de flebotomíneos em dois abrigos de animais, durante o período de um ano, no município de Ilha Solteira, SP. Amostras de material biológico foram coletadas de 192 cães e de 197 gatos, para realização de exames sorológicos por meio do ensaio imunoenzimático indireto (ELISA), da reação de imunofluorescência indireta (RIFI) para ambas espécies animais e da reação intradérmica de Montenegro para cães. Dos cães examinados, 17,2% (33/192) estavam sorologicamente positivos para LV pelo método ELISA, 19,8% (38/192) pela RIFI e 45,4% (15/33) pela reação intradérmica. Para cães, a concordância entre as técnicas sorológicas foi classificada de razoável a boa, mas quando comparadas à reação de Montenegro foi considerada ruim. No inquérito felino das 197 amostras, a soroprevalência foi de 32,4% (64/197) e 31,9% (63/197) no ELISA e RIFI, respectivamente. Embora a maioria dos cães e dos gatos entregue nos abrigos já estivesse infectada, seis cães e cinco gatos infectaram-se no interior desses abrigos, após algum tempo de permanência nesses recintos. Um total de 131 flebotomíneos foram capturados por meio das armadilhas luminosas, colocadas no interior dos dois abrigos durante o período de dois anos. Os fatores de riscos associados à LV foram determinados estatisticamente pela análise univariada, com valor significativo (p ≤ 0,05), onde o porte pequeno dos cães, o uso de coleira de deltametrina e o diagnóstico precoce foram variáveis determinantes que influenciaram a positividade dos animais, ou seja, as duas últimas variáveis determinaram significativamente na diminuição de casos positivos da doença nos... / Abstract: Visceral leishmaniasis (VL), a disease caused by Leishmania infantum and transmitted by the sand fly Lutzomyia longipalpis, is considered a public health problem in Brazil. The study aimed to carry out an epidemiological study on the occurrence of VL in dogs and cats, and sand flies during the period of one year in two animal shelters from Ilha Solteira, SP. A total of 197 and 192 biological material samples were collected, respectively from cats and dogs for serological survey by an indirect enzyme-linked immunosorbent assay (ELISA) and an indirect fluorescent antibody test (IFAT) for both species of animals, and the intradermal reaction of Montenegro (only for dogs). During the study with dogs, 17,2% (33/192) were serologically positive for LV by ELISA, 19,8% (38/192) by IFAT and 45,4% (15/33) by the intradermal method. The correlation analysis between the serological techniques was ranged from reasonable to good for dogs, but was bad when compared to the Montenegro reaction. The feline seroprevalence was 32,4% (64/197) and 31,9% (63/197) for ELISA and IFAT, respectively. Although the most of dogs and cats in shelters were infected, six dogs and five cats infected inside the shelters. A total of 131 sand flies were captured by the light traps in both shelters, during two years. The risk factors, statistically determined by univariate analysis (p ≤ 0.05), demonstrated that the small size of the dogs, the use of deltamethrin collar and the precocious diagnosis, significantly influenced the animals positivity for VL. It was concluded that these animal shelters were vulnerable to this parasitic infection because of the presence of sand flies and positive animals for LV / Mestre

Two hybridoma clones, labelled 4D10 C1 and 2H4 H12, produced monoclonal antibodies which recognized the outer membrane of an enteropathogenic Escherichia coli (EPEC) 0142:K86:H6 in an enzyme-linked immunosorbent assay (ELISA) and the whole cell in an immunofluorescence assay. Large scale production of the monoclonal antibodies was accomplished through ascites production in balb/c mice. Purification of the ascites fluid was achieved by gel filtration and ion exchange chromatography. Isotyping of the purified fractions showed 4D10 C1 to be an IgG2 and 2H4 H12 an IgM. These monoclonal antibodies were screened by immunofluorescence assay against several pathogenic and nonpathogenic strains of E.coli in addition to other Enterobacteriaciae. Results of the screening showed these antibodies to be specific for the E.coli serotype to which they were raised. Minimal cross-reactivity with other Enterobacteriaceae was observed. In a separate and concurrent project, the use of an ELISA capable of detecting ß-N-acetylglucosaminidase (NAGase) was examined. White Leghorn hens were injected with commercially prepared bovine NAGase. Eggs were collected and the immunoglobulin fraction separated from the egg yolk by polyethylene glycol precipitation followed by ion exchange on a DEAE-Sephacel column. The use of the purified immunoglobulins was examined in a sandwich, double-sandwich and a competitive ELISA. A statistically significant standard curve for the detection of NAGase was successfully derived using a double-sandwich ELISA when rabbit immunoglobulin was used to coat the microwell plates. This assay was used to measure the NAGase concentration in press juice and fish extract of fresh and frozen salmon muscle samples. The ratio of the NAGase concentration in the press juice to the total NAGase concentration was compared. No significant difference was found between the calculated concentration ratios of the fresh muscle samples and samples frozen for 1 week at -20°C. / Land and Food Systems, Faculty of / Graduate

[ES] El objetivo de la presente tesis doctoral es el estudio, desarrollo y validación de diferentes métodos inmunoquímicos que permitan determinar contaminantes químicos en alimentos de origen vegetal y en agua, de manera que contribuyan a mejorar su calidad y por ende la seguridad del consumidor. Spirotetramat es un plaguicida de nueva generación altamente eficiente, comercializado mundialmente para su uso como insecticida en multitud de cultivos agrícolas. Tiene propiedades sistémicas, ya que después de la absorción se transloca tanto a través del xilema como del floema, gracias a que es transformado por la planta en spirotetramat-enol, mucho más polar. En consecuencia, la definición de residuo de este insecticida en alimentos de origen vegetal para fines analíticos incluye también dicho metabolito. Por otro lado, anatoxina-a es un alcaloide secundario con neurotoxicidad aguda que se pueden encontrar en agua dulce. Esta toxina es producida por siete géneros diferentes de cianobacterias, y se ha detectado en lagos y otras fuentes de agua de todos los continentes. El análisis de sustancias como spirotetramat y anatoxina-a se lleva a cabo actualmente mediante métodos cromatográficos como HPLC-MS. Estas técnicas presentan una elevada sensibilidad y fiabilidad; sin embargo, requieren personal altamente cualificado y un equipamiento caro y no portable. Una opción complementaria son los métodos inmunoquímicos, como el ELISA (Enzyme-Linked ImmunoSorbent Assay) o el inmunoensayo de flujo lateral (LFIA, Lateral Flow ImmunoAssay), ya que son métodos de análisis rápidos y económicos, y además son muy versátiles permitiendo adaptarlos a necesidades analíticas particulares, como los ensayos de cribado de numerosas muestras o los ensayos portátiles con lectura visual de los resultados. A partir de una colección de bioconjugados y de anticuerpos de spirotetramat y de anatoxina-a se caracterizó la afinidad y especificidad de los inmunorreactivos con el fin de seleccionar parejas conjugado/anticuerpo aptas para el desarrollo de inmunoensayos tipo ELISA y LFIA competitivos. Se optimizaron las condiciones de ensayo, y se llevó a cabo un estudio de la influencia de diferentes factores fisicoquímicos sobre los parámetros analíticos de los ensayos seleccionados. Posteriormente se evaluó la influencia de la matriz alimentaria, particularmente uva, zumo de uva y vino, así como de aguas de diferente procedencia, sobre la señal y la sensibilidad de los inmunoensayos. La diferente afinidad de los anticuerpos hacia spirotetramat y spirotetramat-enol nos llevó a optimizar el tratamiento de muestra, incluyendo una etapa de hidrólisis para transformar spirotetramat en spirotetramat-enol de manera controlada, rápida y cuantitativa. De este modo se hizo posible aportar resultados en forma de suma de la concentración de ambos compuestos en la muestra, tal y como exige la legislación vigente. Además, para la extracción de residuos de este insecticida a partir de muestras de uva se puso a punto un procedimiento empleando la tecnología QuEChERS, y para la reducción de interferencias de vinos y zumos se utilizó polivinilpolipirrolidona. En el caso de las aguas, se aplicó una simple filtración para eliminar partículas en suspensión. Los inmunoensayos enzimáticos en microplaca optimizados para determinar de manera competitiva residuos de spirotetramat presentaron valores de IC50 para spirotetramat-enol en torno a 0.1 ng/mL, y límites de detección alrededor de 0.02 ng/mL. El estudio de la precisión y exactitud del método empleando muestras de alimentos dopados reflejó límites de cuantificación de 2.5 ng/mL para uva, zumos de uva y vinos, tanto blancos como tintos, muy por debajo de los límites máximos de residuos autorizados en la Unión Europea para este insecticida en dichos alimentos. / [EN] The aim of this doctoral thesis is the study, development and validation of different immunochemical methods for determining chemical contaminants in produce and water, in a way that they may contribute to improving food quality and therefore to assure consumer safety. Spirotetramat is a highly efficient new-generation pesticide, marketed worldwide for use as insecticide in many agricultural crops. It has systemic properties, since short after absorption it translocates through both the xylem and the phloem, thanks to the fact that it is transformed by the plant into the much more polar spirotetramat-enol. Consequently, the residue definition for this insecticide in foods of plant origin with analytical purposes also includes said metabolite. On the other hand, anatoxin-a is a secondary alkaloid with acute neurotoxicity that can be found in fresh water. This toxin is produced by seven different genera of cyanobacteria, and has been detected in lakes and other water resources on all continents. The analysis of substances like spirotetramat and anatoxin-a is currently carried out by chromatographic methods like HPLC-MS. These techniques are highly sensitive and reliable; however, they require highly qualified personnel and expensive, non-portable equipment. Nowadays, the immunochemical methods, such as the ELISA (Enzyme-Linked ImmunoSorbent Assay) or the LFIA (Lateral Flow ImmunoAssay), constitute excellent complementary analytical options to instrumental strategies, since they are fast and inexpensive analytical methods, and are also very versatile so they can be adapted to particular analytical needs, such as screening assays for large numbers of samples or portable tests with visual reading of the results. The antibody affinity and specificity from a collection of spirotetramat and anatoxin-a immunoreagents was characterized in order to select conjugate/antibody pairs suitable for the development of competitive ELISA and LFIA tests. The assay conditions were optimized, and a study of the influence of different physicochemical factors over the analytical parameters of the selected immunoassays was carried out. Subsequently, the influence of the food matrix, particularly grape, grape juice and wine, as well as water from different sources, over the assay signal and sensitivity was evaluated. The different affinity of the available antibodies towards spirotetramat and spirotetramat-enol led us to optimize the sample treatment procedure, so a hydrolysis step to transform spirotetramat into spirotetramat-enol in a controlled, rapid and quantitative way, was included. Thus, it was possible to provide results in the form of the sum of the concentration of both compounds in the sample, as required by current legislation. In addition, a procedure using QuEChERS technology was developed to extract residues of this insecticide from grape samples, and polyvinylpolypyrrolidone was used to reduce interferences from wines and juices. In the case of waters, a simple filtration was applied to remove suspended particles. Microplate enzyme immunoassays that were optimized to competitively determine spirotetramat residues showed IC50 values for spirotetramat-enol around 0.1 ng/mL, and limits of detection around 0.02 ng/mL. Precision and accuracy studies with these immunoassays using fortified food samples reflected limits of quantification of 2.5 ng/mL for grapes, grape juices and wines, both white and red, well below the maximum residue limits authorized by the European Union for this insecticide in such foodstuffs. Finally, a comparative study with HPLC-MS/MS validated the studied immunoassay for analyzing spirotetramat residues in grape samples within a wide range of concentrations. / [CA] L’objectiu de la present tesi doctoral és l’estudi, desenvolupament i validació de diferents mètodes immunoquímics que permeten determinar contaminants químics en aliments d’origen vegetal i en aigua, de manera que contribuïsquen a millorar la seua qualitat i per tant la seguretat dels consumidors. Spirotetramat és un plaguicida de nova generació altament eficient, comercialitzat mundialment per a l’ús com insecticida en multitud de cultius agrícoles. Té propietats sistèmiques, ja que en ser absorbit es transloca tant a través del xilema com del floema, gràcies a que és transformat per la planta en spirotetramat-enol, molt més polar. Conseqüentment, la definició de residu d’aquest insecticida en aliments d’origen vegetal amb finalitats analítiques inclou també l’esmentat metabòlit. D’una altra banda, anatoxina-a és un alcaloide secundari amb neurotoxicitat aguda que es pot trobar en aigua dolça. Aquesta toxina és produïda per set gèneres de cianobacteris diferents, i s’ha detectat en llacs i altres fonts d’aigua de tots els continents. L’anàlisi de substàncies com spirotetramat i anatoxina-a es duu a terme actualment mitjançant mètodes cromatogràfics, com HPLC-MS. Aquestes tècniques presenten una elevada sensibilitat i fiabilitat; tanmateix, requereixen personal altament qualificat i un equipament car i no portable. Una opció complementària són els mètodes immunoquímics, com l’ELISA (Enzyme-Linked ImmunoSorbent Assay) o l’immunoassaig de flux lateral (LFIA, Lateral Flow Immunoassay), ja que són mètodes d’anàlisi ràpids i econòmics, i a més són molt versàtils, la qual cosa permet adaptar-los a necessitats analítiques particulars, com són els assaigs per destriar nombroses mostres o els assaigs portàtils amb lectura visual dels resultats. A partir d’una col·lecció de bioconjugats i d’anticossos de spirotetramat i d’anatoxina-a es va caracteritzar l’afinitat i especificitat dels immunorreactius amb la finalitat de seleccionar parelles conjugat/anticòs aptes per desenvolupar immunoassaigs tipus ELISA i LFIA competitius. S’optimitzaren les condicions d’assaig, i es va dur a terme un estudi de la influència de diferents factors fisicoquímics sobre els paràmetres analítics dels assaigs seleccionats. Posteriorment, es va avaluar la influència de la matriu alimentària, particularment raïm, suc de raïm i vi, així com d’aigües de diferent procedència, sobre el senyal i la sensibilitat dels assaigs. La diferent afinitat dels anticossos cap a spirotetramat i spirotetramat-enol ens va dur a optimitzar el tractament de mostra mitjançant la inclusió d’una etapa d’hidròlisi per transformar spirotetramat en spirotetramat-enol de manera ràpida, controlada i quantitativa. D’aquesta manera es va fer possible aportar resultats en forma de suma de la concentració d’ambdós composts en la mostra, tal i com exigeix la legislació vigent. A més a més, per extraure residus d’aquest insecticida a partir de mostres de raïm es va posar a punt un procediment emprant la tecnologia QuEChERS, i per reduir interferències de vins i sucs es va utilitzar polivinilpolipirrolidona. En el cas de les aigües, es va aplicar una simple filtració per eliminar partícules en suspensió. Els immunoassaigs enzimàtics en microplaca optimitzats per determinar de manera competitiva residus de spirotetramat presentaren valors d’IC50 per spirotetramat-enol al voltant de 0.1 ng/mL, i límits de detecció propers a 0.02 ng/mL. L’estudi de la precisió i exactitud del mètode emprant mostres d’aliments dopats va reflectir límits de quantificació de 2.5 ng/mL per raïm, sucs de raïm i vins, tant blancs com negres, molt per sota dels límits màxims de residus autoritzats per la Unió Europea per a aquest insecticida en els esmentats aliments. Finalment, un estudi comparatiu amb HPLC-MS/MS va validar l’immunoassaig estudiat per analitzar residus de spirotetramat en mostres de raïm en un ampli rang de concentracions. En el cas d’anatoxina-a, es van optimitzar dos immunoassaigs tipus ELISA competitiu, els valors d’IC50 dels quals van estar entre 0.5 i 1.0 ng/mL, amb límits de detecció per davall de 0.1 ng/mL. L’anàlisi de diferents tipus d’aigües fortificades amb anatoxina-a ens va revelar que els immunoassaigs desenvolupats permeten quantificar aquesta cianotoxina entre 0.5 i 500 ng/mL. Addicionalment es van optimitzar i caracteritzar assaigs immunocromatogràfics, tipus tires reactives, tant per spirotetramat com per anatoxina-a, vàlids com a tècniques portables i ràpides per determinar semi-quantitativament aquestes substàncies tòxiques en vi i aigües, respectivament. Seguint la normativa europea per a mètodes ràpids front a petites molècules orgàniques, es va determinar el senyal indicatiu del llindar per distingir les mostres positives, que superen la concentració de destriament establerta, de les negatives. En el cas de spirotetramat, el mètode desenvolupat permet el triatge, tant instrumental com visual, amb un interval de confiança del 99%, de mostres de vi amb una concentració de residu de 1000 ng/mL, equivalent al límit màxim de residus, expressada como la suma de spirotetramat més spirotetramat-enol. Per anatoxina-a, les tires immunocromatográfiques desenvolupades van poder detectar mostres d’aigua amb 2 ng/mL de l’esmentada cianotoxina amb una fiabilitat del 99%, i mostres amb 1 ng/mL amb una probabilitat del 40%, mentre que el límit de detecció visual va ser de 3 ng/mL. / A la Secretaría Nacional de Educación Superior, Ciencia, Tecnología e Innovación (SENESCYT), del gobierno de la República de Ecuador que al adjudicarme la beca bajo el “PROGRAMA DE BECAS PARA DOCTORADO (PHD) PARA DOCENTES DE UNIVERSIDADES Y DE ESCUELAS POLITÉCNICAS 2015”, permitió formarme como persona y profesional en mis estudios de doctorado. / Cevallos Cedeño, RE. (2020). Desarrollo de métodos inmunoquímicos para la determinación de sustancias tóxicas en alimentos y aguas [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/149570 / TESIS

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Dentistry. Johannesburg, 2018. / Background: Accurate HIV diagnosis is critical and can be life-saving. A Rapid Test (RT) is considered key to HIV prevention and management. Some studies have found RT to be comparable with ELISA whilst others have reported on lower sensitivity. Aim and study design: The aim of this retrospective comparative descriptive study was to evaluate the sensitivity and specificity of the Tri-line HIV rapid test device in comparison to ELISA on patient records from Wits Oral Health Centre (WOHC) between 2014 and 2016 Method: The study population comprised records of patients older than18 months who had Tri-Line HIV RT and blood drawn for ELISA on the same day. Descriptive analysis of the data was carried out. Results: The sensitivity of Tri-line was 80% (CI: 59-93%) and specificity was 100% (CI: 83-100%). The PPV was 100% (CI: 83-100%) and NPV was 80% (CI: 65-90%). ROC area of 0.9 at 95% CI was determined. Conclusion: Due to a low sample size in this study a definitive conclusion could not be drawn. However on the basis of the results obtained, although the tri-line RT showed lower sensitivity it was shown to be a clinically useful test. / LG2018

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