980 resultados para Immunoassay, Assay validation, Accuracy, recision, Hyperinsulinemia
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Numerous species of mammals are susceptible to Mycobacterium bovis, the causative agent of bovine tuberculosis (TB). Several wildlife hosts have emerged as reservoirs of M. bovis infection for domestic livestock in different countries. In the present study, blood samples were collected from Eurasian badgers (n = 1532), white-tailed deer (n = 463), brushtail possums (n = 129), and wild boar (n = 177) for evaluation of antibody responses to M. bovis infection by a lateral-flow rapid test (RT) and multiantigen print immunoassay (MAPIA). Magnitude of the antibody responses and antigen recognition patterns varied among the animals as determined by MAPIA; however, MPB83 was the most commonly recognized antigen for each host studied. Other seroreactive antigens included ESAT-6, CFP10, and MPB70. The agreement of the RT with culture results varied from 74% for possums to 81% for badgers to 90% for wild boar to 97% for white-tailed deer. Small numbers of wild boar and deer exposed to M. avium infection or paratuberculosis, respectively, did not cross-react in the RT, supporting the high specificity of the assay. In deer, whole blood samples reacted similarly to corresponding serum specimens (97% concordance), demonstrating the potential for field application. As previously demonstrated for badgers and deer, antibody responses to M. bovis infection in wild boar were positively associated with advanced disease. Together, these findings suggest that a rapid TB assay such as the RT may provide a useful screening tool for certain wildlife species that may be implicated in the maintenance and transmission of M. bovis infection to domestic livestock.
Resumo:
The purpose of this study was to examine the reliability, validity and classification accuracy of the South Oaks Gambling Screen (SOGS) in a sample of the Brazilian population. Participants in this study were drawn from three sources: 71 men and women from the general population interviewed at a metropolitan train station; 116 men and women encountered at a bingo venue; and 54 men and women undergoing treatment for gambling. The SOGS and a DSM-IV-based instrument were applied by trained researchers. The internal consistency of the SOGS was 0.75 according to the Cronbach`s alpha model, and construct validity was good. A significant difference among groups was demonstrated by ANOVA (F ((2.238)) = 221.3, P < 0.001). The SOGS items and DSM-IV symptoms were highly correlated (r = 0.854, P < 0.01). The SOGS also presented satisfactory psychometric properties: sensitivity (100), specificity (74.7), positive predictive rate (60.7), negative predictive rate (100) and misclassification rate (0.18). However, a cut-off score of eight improved classification accuracy and reduced the rate of false positives: sensitivity (95.4), specificity (89.8), positive predictive rate (78.5), negative predictive rate (98) and misclassification rate (0.09). Thus, the SOGS was found to be reliable and valid in the Brazilian population.
Resumo:
A simple and sensitive analytical method for simultaneous determination of anastrozole, bicalutamide, and tamoxifen as well as their synthetic impurities, anastrozole pentamethyl, bicalutamide 3-fluoro-isomer, and tamoxifen e-isomer, was developed and validated by using high performance liquid chromatography (HPLC). The separation was achieved on a Symmetry (R) C-8 column (100 x 4.6 mm i.d., 3.5 mu m) at room temperature (+/- 24 degrees C), with a mobile phase consisting of acetonitrile/water containing 0.18% N,N dimethyloctylamine and pH adjusted to 3.0 with orthophosphoric acid (46.5/53.5, v/v) at a flow rate of 1.0 mL min(-1) within 20 min. The detection was made at a wavelength of 270 nm by using ultraviolet (UV) detector. No interference peaks from excipients and relative retention time indicated the specificity of the method. The calibration curve showed correlation coefficients (r) > 0.99 calculated by linear regression and analysis of variance (ANOVA). The limit of detection (LOD) and limit of quantitation (LOQ), respectively, were 2.2 and 6.7 mu g mL(-1) for anastrozole, 2.61 and 8.72 mu g mL(-1) for bicalutamide, 2.0 and 6.7 mu g mL(-1) for tamoxifen, 0.06 and 0.22 mu g mL(-1) for anastrozole pentamethyl, 0.02 and 0.07 mu g mL(-1) for bicalutamide 3-fluoro-isomer, and 0.002 and 0.007 mu g mL(-1) for tamoxifen e-isomer. Intraday and interday relative standard deviations (RSDs) were <2.0% (drugs) and <10% (degradation products) as well as the comparison between two different analysts, which were calculated by f test. (C) 2012 Elsevier B.V. All rights reserved.
Resumo:
The objective of the present study was to compare the performance of three serological tests for diagnosis of Brucella abortus infections in buffaloes (Bubalus bubalis). Serum samples collected from 696 adult females were submitted to the competitive enzyme-linked immunosorbent assay (ELISAC), (I-ELISA), fluorescence polarization test (FPA), 2-mercaptoethanol test (2-ME) and complement fixation test (CFT). The gold standard was the combination of CFT and 2-ME, considering as positive the reactors in both CFT and 2-ME, and as negative those non-reactors. ROC analyses were done for C-ELISA, I-ELISA and FPA and the Kappa agreement index were also calculated. The best combinations of relative sensitivity (SEr) and relative specificity (SPr) and Kappa were given by C-ELISA (96.9%, 99.1%, and 0.932, respectively) and FPA (92.2%, 97.6 and 0.836, respectively). The C-ELISA and FPA were the most promising confirmatory tests for the serological diagnosis of brucellosis in buffaloes, and for these tests, cut-off values for buffaloes may be the same as those used for bovines.
Resumo:
Background: Stable angina pectoris is a serious condition with few epidemiological studies in Brazil. Objective: To validate the short-version of the Rose angina questionnaire in Brazilian Portuguese for its implementation in surveys and longitudinal studies. Methods: A total of 116 consecutive patients from an outpatient clinic without prior myocardial infarction and/or coronary revascularization were enrolled for application of three questions of the Rose angina questionnaire addressing chest pain after exertion. We used the treadmill test as the gold standard with the Ellestad protocol. Results: The short-version of the Rose angina questionnaire of the 116 subjects submitted to the exercise treadmill test disclosed 89.7% of accuracy, 25% of sensitivity, 92.0% of specificity, 10.0% of positive predictive value, 97.2% of negative predictive value, and 3.1 of positive likelihood ratio and 0.82 of negative likelihood ratio. Conclusion: The Portuguese version with three items of the Rose angina questionnaire is suitable for epidemiological purposes. (Arq Bras Cardiol 2012; 99(5): 1056-1059)
Resumo:
Abstract Background From shotgun libraries used for the genomic sequencing of the phytopathogenic bacterium Xanthomonas axonopodis pv. citri (XAC), clones that were representative of the largest possible number of coding sequences (CDSs) were selected to create a DNA microarray platform on glass slides (XACarray). The creation of the XACarray allowed for the establishment of a tool that is capable of providing data for the analysis of global genome expression in this organism. Findings The inserts from the selected clones were amplified by PCR with the universal oligonucleotide primers M13R and M13F. The obtained products were purified and fixed in duplicate on glass slides specific for use in DNA microarrays. The number of spots on the microarray totaled 6,144 and included 768 positive controls and 624 negative controls per slide. Validation of the platform was performed through hybridization of total DNA probes from XAC labeled with different fluorophores, Cy3 and Cy5. In this validation assay, 86% of all PCR products fixed on the glass slides were confirmed to present a hybridization signal greater than twice the standard deviation of the deviation of the global median signal-to-noise ration. Conclusions Our validation of the XACArray platform using DNA-DNA hybridization revealed that it can be used to evaluate the expression of 2,365 individual CDSs from all major functional categories, which corresponds to 52.7% of the annotated CDSs of the XAC genome. As a proof of concept, we used this platform in a previously work to verify the absence of genomic regions that could not be detected by sequencing in related strains of Xanthomonas.
Resumo:
The objective of this study was to validate three different models for predicting milk urea nitrogen using field conditions, attempting to evaluate the nutritional adequacy diets for dairy cows and prediction of nitrogen excreted to the environment. Observations (4,749) from 855 cows were used. Milk yield, body weight (BW), days in milk and parity were recorded on the milk sampling days. Milk was sampled monthly, for analysis of milk urea nitrogen (MUN), fat, protein, lactose and total solids concentration and somatic cells count. Individual dry matter intake was estimated using the NRC (2001). The three models studied were derived from a first one to predict urinary nitrogen (UN). Model 1 was MUN = UN/12.54, model 2 was MUN = UN/17.6 and model 3 was MUN = UN/(0.0259 × BW), adjusted by body weight effect. To evaluate models, they were tested for accuracy, precision and robustness. Despite being more accurate (mean bias = 0.94 mg/dL), model 2 was less precise (residual error = 4.50 mg/dL) than model 3 (mean bias = 1.41 and residual error = 4.11 mg/dL), while model 1 was the least accurate (mean bias = 6.94 mg/dL) and the least precise (residual error = 5.40 mg/dL). They were not robust, because they were influenced by almost all the variables studied. The three models for predicting milk urea nitrogen were different with respect to accuracy, precision and robustness.
Resumo:
The aim of this study was to compare the techniques of indirect immunofluorescence assay (IFA) and flow cytometry to clinical and laboratorial evaluation of patients before and after clinical cure and to evaluate the applicability of flow cytometry in post-therapeutic monitoring of patients with American tegumentary leishmaniasis (ATL). Sera from 14 patients before treatment (BT), 13 patients 1 year after treatment (AT), 10 patients 2 and 5 years AT were evaluated. The results from flow cytometry were expressed as levels of IgG reactivity, based on the percentage of positive fluorescent parasites (PPFP). The 1:256 sample dilution allowed us to differentiate individuals BT and AT. Comparative analysis of IFA and flow cytometry by ROC (receiver operating characteristic curve) showed, respectively, AUC (area under curve) = 0.8 (95% CI = 0.64–0.89) and AUC = 0.90 (95% CI = 0.75–0.95), demonstrating that the flow cytometry had equivalent accuracy. Our data demonstrated that 20% was the best cut-off point identified by the ROC curve for the flow cytometry assay. This test showed a sensitivity of 86% and specificity of 77% while the IFA had a sensitivity of 78% and specificity of 85%. The after-treatment screening, through comparative analysis of the technique performance indexes, 1, 2 and 5 years AT, showed an equal performance of the flow cytometry compared with the IFA. However, flow cytometry shows to be a better diagnostic alternative when applied to the study of ATL in the cure criterion. The information obtained in this work opens perspectives to monitor cure after treatment of ATL.
Resumo:
Background. The surgical treatment of dysfunctional hips is a severe condition for the patient and a costly therapy for the public health. Hip resurfacing techniques seem to hold the promise of various advantages over traditional THR, with particular attention to young and active patients. Although the lesson provided in the past by many branches of engineering is that success in designing competitive products can be achieved only by predicting the possible scenario of failure, to date the understanding of the implant quality is poorly pre-clinically addressed. Thus revision is the only delayed and reliable end point for assessment. The aim of the present work was to model the musculoskeletal system so as to develop a protocol for predicting failure of hip resurfacing prosthesis. Methods. Preliminary studies validated the technique for the generation of subject specific finite element (FE) models of long bones from Computed Thomography data. The proposed protocol consisted in the numerical analysis of the prosthesis biomechanics by deterministic and statistic studies so as to assess the risk of biomechanical failure on the different operative conditions the implant might face in a population of interest during various activities of daily living. Physiological conditions were defined including the variability of the anatomy, bone densitometry, surgery uncertainties and published boundary conditions at the hip. The protocol was tested by analysing a successful design on the market and a new prototype of a resurfacing prosthesis. Results. The intrinsic accuracy of models on bone stress predictions (RMSE < 10%) was aligned to the current state of the art in this field. The accuracy of prediction on the bone-prosthesis contact mechanics was also excellent (< 0.001 mm). The sensitivity of models prediction to uncertainties on modelling parameter was found below 8.4%. The analysis of the successful design resulted in a very good agreement with published retrospective studies. The geometry optimisation of the new prototype lead to a final design with a low risk of failure. The statistical analysis confirmed the minimal risk of the optimised design over the entire population of interest. The performances of the optimised design showed a significant improvement with respect to the first prototype (+35%). Limitations. On the authors opinion the major limitation of this study is on boundary conditions. The muscular forces and the hip joint reaction were derived from the few data available in the literature, which can be considered significant but hardly representative of the entire variability of boundary conditions the implant might face over the patients population. This moved the focus of the research on modelling the musculoskeletal system; the ongoing activity is to develop subject-specific musculoskeletal models of the lower limb from medical images. Conclusions. The developed protocol was able to accurately predict known clinical outcomes when applied to a well-established device and, to support the design optimisation phase providing important information on critical characteristics of the patients when applied to a new prosthesis. The presented approach does have a relevant generality that would allow the extension of the protocol to a large set of orthopaedic scenarios with minor changes. Hence, a failure mode analysis criterion can be considered a suitable tool in developing new orthopaedic devices.
Resumo:
Die vorliegende Dissertation entstand im Rahmen eines multizentrischen EU-geförderten Projektes, das die Anwendungsmöglichkeiten von Einzelnukleotid-Polymorphismen (SNPs) zur Individualisierung von Personen im Kontext der Zuordnung von biologischen Tatortspuren oder auch bei der Identifizierung unbekannter Toter behandelt. Die übergeordnete Zielsetzung des Projektes bestand darin, hochauflösende Genotypisierungsmethoden zu etablieren und zu validieren, die mit hoher Genauigkeit aber geringen Aufwand SNPs im Multiplexformat simultan analysieren können. Zunächst wurden 29 Y-chromosomale und 52 autosomale SNPs unter der Anforderung ausgewählt, dass sie als Multiplex eine möglichst hohe Individualisierungschance aufweisen. Anschließend folgten die Validierungen beider Multiplex-Systeme und der SNaPshot™-Minisequenzierungsmethode in systematischen Studien unter Beteiligung aller Arbeitsgruppen des Projektes. Die validierte Referenzmethode auf der Basis einer Minisequenzierung diente einerseits für die kontrollierte Zusammenarbeit unterschiedlicher Laboratorien und andererseits als Grundlage für die Entwicklung eines Assays zur SNP-Genotypisierung mittels der elektronischen Microarray-Technologie in dieser Arbeit. Der eigenständige Hauptteil dieser Dissertation beschreibt unter Verwendung der zuvor validierten autosomalen SNPs die Neuentwicklung und Validierung eines Hybridisierungsassays für die elektronische Microarray-Plattform der Firma Nanogen Dazu wurden im Vorfeld drei verschiedene Assays etabliert, die sich im Funktionsprinzip auf dem Microarray unterscheiden. Davon wurde leistungsorientiert das Capture down-Assay zur Weiterentwicklung ausgewählt. Nach zahlreichen Optimierungsmaßnahmen hinsichtlich PCR-Produktbehandlung, gerätespezifischer Abläufe und analysespezifischer Oligonukleotiddesigns stand das Capture down-Assay zur simultanen Typisierung von drei Individuen mit je 32 SNPs auf einem Microarray bereit. Anschließend wurde dieses Verfahren anhand von 40 DNA-Proben mit bekannten Genotypen für die 32 SNPs validiert und durch parallele SNaPshot™-Typisierung die Genauigkeit bestimmt. Das Ergebnis beweist nicht nur die Eignung des validierten Analyseassays und der elektronischen Microarray-Technologie für bestimmte Fragestellungen, sondern zeigt auch deren Vorteile in Bezug auf Schnelligkeit, Flexibilität und Effizienz. Die Automatisierung, welche die räumliche Anordnung der zu untersuchenden Fragmente unmittelbar vor der Analyse ermöglicht, reduziert unnötige Arbeitsschritte und damit die Fehlerhäufigkeit und Kontaminationsgefahr bei verbesserter Zeiteffizienz. Mit einer maximal erreichten Genauigkeit von 94% kann die Zuverlässigkeit der in der forensischen Genetik aktuell eingesetzten STR-Systeme jedoch noch nicht erreicht werden. Die Rolle des neuen Verfahrens wird damit nicht in einer Ablösung der etablierten Methoden, sondern in einer Ergänzung zur Lösung spezieller Probleme wie z.B. der Untersuchung stark degradierter DNA-Spuren zu finden sein.
Resumo:
The evaluation of chronic activity of the hypothalamic-pituitary-adrenal (HPA) axis is critical for determining the impact of chronic stressful situations. The potential use of hair glucocorticoids as a non-invasive, retrospective, biomarker of long term HPA activity is of great interest, and it is gaining acceptance in humans and animals. However, there are still no studies in literature examining hair cortisol concentration in pigs and corticosterone concentration in laboratory rodents. Therefore, we developed and validated, for the first time, a method for measuring hair glucocorticoids concentration in commercial sows and in Sprague-Dawley rats. Our preliminary data demonstrated: 1) a validated and specific washing protocol and extraction assay method with a good sensitivity in both species; 2) the effect of the reproductive phase, housing conditions and seasonality on hair cortisol concentration in sows; 3) similar hair corticosterone concentration in male and female rats; 4) elevated hair corticosterone concentration in response to chronic stress manipulations and chronic ACTH administration, demonstrating that hair provides a good direct index of HPA activity over long periods than other indirect parameters, such adrenal or thymus weight. From these results we believe that this new non-invasive tool needs to be applied to better characterize the overall impact in livestock animals and in laboratory rodents of chronic stressful situations that negatively affect animals welfare. Nevertheless, further studies are needed to improve this methodology and maybe to develop animal models for chronic stress of high interest and translational value in human medicine.
Resumo:
The aim of this PhD thesis " Simulation Guided Navigation in cranio- maxillo- facial surgery : a new approach to Improve intraoperative three-dimensional accuracy and reproducibility during surgery ." was at the center of its attention the various applications of a method introduced by our School in 2010 and has as its theme the increase of interest of reproducibility of surgical programs through methods that in whole or in part are using intraoperative navigation. It was introduced in Orthognathic Surgery Validation a new method for the interventions carried out according to the method Simulation Guided Navigation in facial deformities ; was then analyzed the method of three-dimensional control of the osteotomies through the use of templates and cutting of plates using the method precontoured CAD -CAM and laser sintering . It was finally proceeded to introduce the method of piezonavigated surgery in the various branches of maxillofacial surgery . These studies have been subjected to validation processes and the results are presented .
Resumo:
In den letzten Jahren stieg in Deutschland der Gebrauch bzw. Missbrauch von Opioid-Analgetika zunehmend an. Das entwickelte Verfahren sollte unter Einbeziehung neuer Substanzen möglichst viele verschiedene Opioide und auch ihre pharmakologisch aktiven Stoffwechselprodukte berücksichtigen.rnVor Analyse wurden Blut-, Serum- oder Urinproben mit Phosphatpuffer versetzt und mittels Festphasenextraktion an C18-Säulenmaterial aufgearbeitet. Post-Mortem-Gewebematerial wurde mit isotonischer Kochsalzlösung versetzt, homogenisiert und anschließend durch eine Festphasenextraktion aufgereinigt. Haarproben wurden nach Zerkleinerung mit Methanol unter Ultrabeschallung extrahiert. Die Flüssigchromatographie gekoppelt mit Tandem-Massenspektrometrie (Elektrosprayionisation im positiven Modus) erwies sich als geeignetes Verfahren für die simultane Bestimmung der Opioide in biologischem Probenmaterial (Körperflüssigkeiten, Gewebe und Haaren). Der Multi-Analyt Assay erlaubt die quantitative Analyse von 35 verschiedenen Opioiden. Die Analyten wurden durch eine Phenyl-Hexyl Säule und einen Wasser/Acetonitril Gradienten durch eine UPLC 1290 Infinity gekoppelt mit einem 6490 Triple Quadrupol von Agilent Technologies separiert.rnDie LC/MS Methode zur simultanen Bestimmung von 35 Opioiden in Serum und Haaren wurde nach den Richtlinien der Gesellschaft für Toxikologische und Forensische Chemie (GTFCh) validiert. Im Fall der Serumvalidierung lagen die Nachweisgrenzen zwischen 0.02 und 0.6 ng/ml und die Bestimmungsgrenzen im Bereich von 0.1 bis 2.0 ng/ml. Die Kalibrationskurven waren für die Kalibrationslevel 1 bis 6 linear. Wiederfindungsraten lagen für alle Verbindungen zwischen 51 und 88 %, außer für Alfentanil, Bisnortiliidn, Pethidin und Morphin-3-Glucuronid. Der Matrixeffekt lag zwischen 86 % (Ethylmorphin) und 105 % (Desomorphin). Für fast alle Analyten konnten akzeptable Werte bei der Bestimmung der Genauigkeit und Richtigkeit nach den Richtlinien der GTFCh erhalten werden. Im Fall der Validierung der Haarproben lagen die Nachweisgrenzen zwischen 0.004 und 0.6 ng/Probe und die Bestimmungsgrenzen zwischen 0.1 ng/Probe und 2.0 ng/Probe. Für die Kalibrationslevel 1 bis 6 waren alle Kalibrationsgeraden linear. Die Wiederfindungsraten lagen für die Opioide im Bereich von 73.5 % (Morphin-6-Glucuronid) und 114.1 % (Hydrocodon). Die Werte für die Bestimmung der Richtigkeit lagen zwischen - 6.6 % (Methadon) und + 11.7 % (Pholcodin). Präzisionsdaten wurden zwischen 1.0 % für Dextromethorphan und 11.5 % für Methadon ermittelt. Die Kriterien der GTFCh konnten bei Ermittlung des Matrixeffekts für alle Substanzen erfüllt werden, außer für 6-Monoacetylmorphin, Bisnortilidin, Meperidin, Methadon, Morphin-3-glucuronid, Morphin-6-glucuronid, Normeperidin, Nortilidin und Tramadol.rnZum Test des Verfahrens an authentischem Probenmaterial wurden 206 Proben von Körperflüssigkeiten mit Hilfe der simultanen LC/MS Screening Methode untersucht. Über 150 Proben wurden im Rahmen von forensisch-toxikologischen Untersuchungen am Instituts für Rechtsmedizin Mainz analysiert. Dabei konnten 23 der 35 Opioide in den realen Proben nachgewiesen werden. Zur Untersuchung der Pharmakokinetik von Opioiden bei Patienten der anästhesiologischen Intensivstation mit Sepsis wurden über 50 Blutproben untersucht. Den Patienten wurde im Rahmen einer klinischen Studie einmal täglich vier Tage lang Blut abgenommen. In den Serumproben wurde hauptsächlich Sufentanil (0.2 – 0.8 ng/ml in 58 Fällen) und Piritramid (0.4 – 11 ng/ml in 56 Fällen) gefunden. Außerdem wurden die Proben von Körperflüssigkeiten und Gewebe von 13 verschiedenen Autopsiefällen mit Hilfe des Multi-Analyt Assays auf Opioide untersucht.rnIn einem zweiten Schritt wurde die Extraktions- und Messmethode zur Quantifizierung der 35 Opioide am Forensic Medicine Center in Ho Chi Minh City (Vietnam) etabliert. Insgesamt wurden 85 Herzblutproben von Obduktionsfällen mit Verdacht auf Opiatintoxikation näher untersucht. Der überwiegende Teil der untersuchten Fälle konnte auf eine Heroin- bzw. Morphin-Vergiftung zurückgeführt werden. Morphin wurde in 68 Fällen im Konzentrationsbereich 1.7 – 1400 ng/ml und der Heroinmetabolit 6-Monoactetylmorphin in 34 Fällen (0.3 – 160 ng/ml) nachgewiesen werden.rnSchließlich wurden noch 15 Haarproben von Patienten einer psychiatrischen Klinik, die illegale Rauschmittel konsumiert hatten, mit Hilfe der simultanen Opioid-LC/MS Screeningmethode gemessen. Die Ergebnisse der Untersuchung wurden mit früheren Auswertungen von gaschromatographischen Analysen verglichen. Es zeigte sich eine weitgehende Übereinstimmung der Untersuchungsergebnisse für die Opioide 6-Monoacetylmorphin, Morphin, Codein, Dihydrocodein und Methadon. Mit der LC/MS Methode konnten weitere Substanzen, wie zum Beispiel Bisnortilidin, Dextromethorphan und Tramadol in den Haarproben gefunden werden, die bislang nicht entdeckt worden waren.rn