RESUMEN
The POC-CCA test is subject to variations in reading interpretations depending on the intensity of its results, and trace test reading have implications for determining prevalence. The aim of this study was to assess whether the readings obtained from the POC-CCA tests, conducted using a semi-quantitative scale (the G-score classification for test determination), exhibited concurrence with the direct visual interpretation (positive, negative, or trace) performed by two distinct analysts, using photographs from previously performed POC-CCA test carried out in the municipality of Maruim, in the state of Sergipe-Brazil, a region of high endemicity. The devices used to read the photographs were smartphones, so as to simulate field usage, and a desktop, a tool with higher image quality that would help the researchers in the evaluation and establishment of the final result at a later. In direct visual interpretation of the POC-CCA photographs, the most discordant results occurred in the identification of the trace response (T). The Kappa index established for the direct visual interpretation between the two analysts, in which T is considered as positive, in the desktop was κ=0.826 and in the smartphone, κ=0.950. When we use the G-score as a reading standardization technique and classify the results according to the manufacturer, with trace being evaluated as positive, the highest level of agreement was obtained. Some disagreement remains between the direct visual interpretation and the G-score when performed on the desktop, with more individuals being classified as negative in the direct visual interpretation, by both analysts. However, this result was not statistically significant. The use of the G-score scale proved to be an excellent tool for standardizing the readings and classifying the results according to the semi-quantitative scale showed greater concordance of results both among analysts and among the different devices used to view the photographs.
Asunto(s)
Cromatografía de Afinidad , Brasil/epidemiología , Humanos , Cromatografía de Afinidad/métodos , Cromatografía de Afinidad/instrumentación , Esquistosomiasis mansoni/diagnóstico , Esquistosomiasis mansoni/epidemiología , Heces/parasitología , Animales , Sensibilidad y Especificidad , Enfermedades EndémicasRESUMEN
Abstract Cannabis sativa L. is one of the most consumed drugs in the world and recent studies have associated its use with an increase in the number of traffic accidents in different countries. In many countries, like Brazil, simple and reliable methodologies are still needed for the detection of drugs on site, mainly cannabinoids, considering its prevalence of use and oral fluid (OF) has been proved as an appropriate biological matrix for this purpose. Considering that, this work aims to review previous studies on immunochromatographic devices for on-site detection of cannabinoids in OF, discussing their sensitivity, specificity, cut-offs values and confirmatory methods. This data shows the importance of choosing a screening device and it reinforces the need for its implementation in Brazil. The research was conducted on 5 databases and all original articles, published in the last 10 years, were selected. A total of 32 articles were found, providing data for 17 screening devices of distinct brands. Only 2 screening devices showed satisfactory sensitivity and specificity in the evaluated studies (≥80% and ≥90% respectively). However, it should be considered that the screening devices still have some limitations, such as a higher cut-off than those recommended by international guidelines (cut-off > 2 ng/mL), therefore demonstrating the need for more studies in the area and the importance of confirmatory analysis usually fulfilled by LC-MS/MS, GC-MS/MS or GC-MS. Thus, the screening analyzes should not be evaluated by itself, but in association with confirmatory results and observational traits (behavioral changes), for a better understanding of the traffic scenario
Asunto(s)
Cannabinoides/análisis , Triaje/clasificación , Cromatografía de Afinidad/instrumentación , Dronabinol/agonistas , Cannabis/efectos adversos , Accidentes de Tránsito/prevención & control , Detección de Abuso de Sustancias/instrumentaciónRESUMEN
Abstract With the COVID-19 pandemic, many diagnostic tests (molecular or immunological) were rapidly standardised, given the urgency of the situation, many are still in the process of being validated. The main objective of this study was to review the aspects of the diagnostic kits approved in Brazil and their application in the different federative units to gather epidemiological information. In order to achieve these objectives, a survey was carried out on the data available at the regulatory agency (ANVISA) and in the literature. The main countries that have registered products in Brazil are China (51.4%), Brazil (16.6%), South Korea (9.2%), USA (8.8%) and Germany (3.6%). The methodologies of these products are based on the detection of nucleic-acid (15.8%), antigen (13%) and antibody (71.2%). In the immunological tests, it was verified that the sensitivity ranged from 55 to 100% and the specificity from 80 to 100%. The percentage of cases in the samples tested in Brazil is elevated in almost all federative units since eight states showed 40% of positive cases in tested samples, while 18 states displayed between 20 and 40%. In conclusion, this review showed that Brazil is dependent on external technology to respond to pandemics, epidemics and endemics disease and needs to improve its biotechnological scheme to solve further diseases outbreaks.
Asunto(s)
Humanos , Coronavirus Relacionado al Síndrome Respiratorio Agudo Severo/aislamiento & purificación , COVID-19/diagnóstico , Pruebas Inmunológicas/instrumentación , Brasil/epidemiología , Ensayo de Inmunoadsorción Enzimática/instrumentación , Cromatografía de Afinidad/instrumentación , Prueba de COVID-19/instrumentación , Prueba de Ácido Nucleico para COVID-19/métodosRESUMEN
Despite several available methodologies for Chagas disease (CD) serological screening, the main limitation of chronic CD diagnosis is the lack of effective tools for large-scale screening and point-of-care diagnosis to be used in different CD epidemiological scenarios. Taking into account that developing such a diagnostic tool will significantly improve the ability to identify CD carriers, we aimed at performing a proof-of-concept study (phase I study) to assess the use of these proteins in a point-of-care platform using serum samples from different geographical settings of Brazil and distinct clinical presentations. The diagnostic accuracy study was conducted on a panel of two WHO International Standards (IS) and 14 sera from T. cruzi-positive and 16 from T. cruzi-negative individuals. The results obtained with the test strips were converted to digital images, allowing quantitative comparison expressed as a relative band intensity ratio (RBI). The diagnostic potential and performance were also determined. Regardless of the geographical origin or clinical presentation, all sera with T. cruzi antibodies returned positive both for IBMP-8.1 and IBMP-8.4 chimeric antigens. The area under the ROC curve (AUC) values was 100% for both antigens, demonstrating an outstanding overall diagnostic accuracy (100%). Based on the data, we believe that the lateral flow assays based on these antigens are promising methodologies for screening CD.
Asunto(s)
Anticuerpos Antiprotozoarios/sangre , Antígenos de Protozoos/inmunología , Enfermedad de Chagas/diagnóstico , Inmunoensayo/métodos , Trypanosoma cruzi/inmunología , Antígenos de Protozoos/genética , Brasil , Enfermedad de Chagas/inmunología , Enfermedad de Chagas/parasitología , Cromatografía de Afinidad/instrumentación , Cromatografía de Afinidad/métodos , Ensayo de Inmunoadsorción Enzimática/instrumentación , Ensayo de Inmunoadsorción Enzimática/métodos , Diseño de Equipo , Humanos , Inmunoensayo/instrumentación , Pruebas en el Punto de Atención , Prueba de Estudio Conceptual , Proteínas Protozoarias/genética , Proteínas Protozoarias/inmunología , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/inmunología , Trypanosoma cruzi/genéticaRESUMEN
INTRODUÇÃO: O coronavírus da Síndrome Respiratória Aguda Grave 2 (abreviado para SARSCoV-2, do inglês Severe Acute Respiratory Syndrome Coronavirus 2), anteriormente conhecido como novo coronavírus (2019-nCoV), é um agente zoonótico recémemergente que surgiu em dezembro de 2019, em Wuhan, China, causando manifestações respiratórias, digestivas e sistêmicas, que se articulam no quadro clínico da doença denominada COVID-19 (do inglês Coronavirus Disease 2019). Ainda não há informações robustas sobre a história natural da doença, tampouco sobre as medidas de efetividade para o manejo clínico dos casos de infecção pelo COVID19, restando ainda muitos detalhes a serem esclarecidos. No entanto, sabe-se que o vírus tem alta transmissibilidade e provoca uma síndrome respiratória aguda que varia de casos leves cerca de 80% a casos muito graves com insuficiência respiratória - entre 5% e 10% dos casos , os quais requerem tratamento especializado em unidades de terapia intensiva (UTI). Sua letalidade varia, principalmente, conforme a faixa etária. TECNOLOGIA: Os testes de diagnóstico para a COVID-19 se destacaram na pandemia de coronavírus em andamento como uma ferramenta essencial para rastrear a propagação da doença. Uma ampla gama de testes diagnósticos para o SARS-CoV-2 está disponível comercialmente, alguns dos quais receberam autorizações para uso por várias agências reguladoras nacionais. Com as informações da sequência genética devidamente identificadas, os testes de diagnóstico baseados na detecção da sequência viral por reação em cadeia da polimerase com transcriptase reversa (RT-PCR) ou plataformas de sequenciamento logo se tornaram disponíveis. Isso permitiu a confirmação do diagnóstico e melhores estimativas da atividade da infecção, que vêm aumentando em velocidades alarmantes. Para a detecção mais sensível de SARS-CoV, MERS-CoV e SARS-CoV-2, recomendavam-se a coleta e o teste de amostras respiratórias superiores e inferiores. O diagnóstico de casos suspeitos era confirmado por testes de RNA com RT-PCR em tempo real ou sequenciamento de próxima geração. Foi demonstrado que o RNA viral poderia ser detectado a partir do swab nasal e faríngeo, lavagem broncoalveolar e plasma sanguíneo usando RT-PCR direcionado ao gene do vírus (5). O padrão-ouro para diagnóstico laboratorial da COVID-19 é a reação da transcriptase reversa, seguida de reação em cadeia da polimerase (RT-PCR) para amostras coletadas no trato respiratório superior ou inferior. OBJETIVO: O objetivo deste relatório é analisar a acurácia dos testes diagnósticos registrados na Agência Nacional de Vigilância Sanitária (ANVISA) até a presente data. METODOLOGIA: foi realizada uma busca por diagnósticos para COVID-19 com registros vigentes na ANVISA. Para tal, foram utilizados os termos "COVID 19", SARS e coronavírus no campo de consulta de registro de produtos para saúde no site da Agência (https://consultas.anvisa.gov.br/#/saude/). Os passos para acesso ao banco de dados de produtos diagnósticos na ANVISA são: 1) consulta produtos; 2) consulta a banco de dados; 3) produtos para a saúde e 4) pesquisa de produtos para a saúde registrados. CONCLUSÕES: A ANVISA já avaliou mais de 120 pedidos de registro de produtos para testagens relacionadas à COVID-19 desde o dia 18 de março. A maior parte das petições aguarda complementação de informações por parte das empresas e outras estão sendo analisadas com prioridade. O tempo médio para avaliação dos registros na ANVISA gira em torno de 15 dias. Atualmente, mais da metade dos registros concedidos diz respeito a testes rápidos para anticorpos. Até a presente data, foram registrados 64 testes para diagnóstico da COVID-19, sendo 15 deles moleculares. O teste de polymerase chain reaction em tempo real (RT-PCR) para identificação de SARS-CoV-2 é um teste de elevada sensibilidade e especificidade, ainda que os doentes com maior carga viral possam ter maior probabilidade de um teste positivo. Os testes moleculares baseados em RNA exigem instalações laboratoriais específicas com níveis restritos de biossegurança e técnica. A sensibilidade e especificidade dos testes sorológicos variaram entre os fabricantes. É importante destacar que uma baixa sensibilidade do teste diagnóstico pode resultar em uma maior probabilidade de detectar falsos-negativos, o que poderia interferir principalmente em casos de indivíduos assintomáticos. Em geral, a sensibilidade dos testes foi superior a 85% e a especificidade, superior a 94%. Os testes sorológicos medem a quantidade de dois anticorpos (IgG e IgM) que o organismo produz quando entra em contato com um invasor. Contudo, o desenvolvimento da resposta de um anticorpo à infecção pode ser dependente do hospedeiro e levar tempo. No caso de SARS-CoV-2, estudos iniciais sugerem que a maioria dos pacientes se converte entre 7 e 11 dias após a exposição ao vírus, embora alguns pacientes possam desenvolver anticorpos mais cedo. Devido a esse atraso natural, o teste de anticorpos pode não ser útil no cenário de uma doença aguda (11). Os testes de anticorpos para SARS-CoV-2 podem facilitar (i) o rastreamento de contatos (os testes baseados em RNA também podem ajudar); (ii) a vigilância sorológica nos níveis local, regional, estadual e nacional; e (iii) a identificação de quem já teve contato com o vírus e, portanto, pode (se houver imunidade protetora) ser imune (11,12). Alguns conjuntos de reagentes para testes sorológicos foram autorizados pela ANVISA em caráter emergencial devido à gravidade da situação e à necessidade de ampliar a testagem da população, mas a validação desses reagentes pelos laboratórios é fundamental, uma vez que poucos trabalhos conseguiram ser publicados até o momento. As aprovações estão de acordo com a Resolução da Diretoria Colegiada (RDC) 348/2020, que define os critérios e os procedimentos extraordinários e temporários para tratamento de petições de registro de medicamentos, produtos biológicos e produtos para diagnóstico in vitro, e mudança pós-registro de medicamentos e produtos biológicos em virtude da emergência de saúde pública internacional decorrente do novo coronavírus. Na RDC, para registro de testes diagnósticos, a ausência de qualquer estudo de desempenho ou restrição de dados deve ser justificada por motivações técnicas que permitam a avalição da confiabilidade dos resultados e da efetividade diagnóstica do produto. Os registros concedidos nas condições dessa Resolução terão a validade de um ano, exceto para situações em que a avaliação da estabilidade seja apresentada por comparação com produtos similares e os demais critérios descritos no Regulamento sejam atendidos. Nesse caso, poderão ter a concessão regular de validade de registro de produtos para saúde por um período de 10 anos. Em resumo, as duas categorias de testes para SARS-CoV-2 podem ser úteis nesse surto, pois, eventualmente, a coleta de múltiplas amostras, regiões e em tempos diferentes durante a evolução da doença pode ser necessária para o diagnóstico da COVID-19.
Asunto(s)
Humanos , Ensayo de Inmunoadsorción Enzimática/instrumentación , Cromatografía de Afinidad/instrumentación , Técnica del Anticuerpo Fluorescente/instrumentación , Infecciones por Coronavirus/diagnóstico , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/instrumentación , Evaluación de la Tecnología Biomédica , Evaluación en SaludRESUMEN
Sistemas de Secreção Tipo IV (T4SSs), normalmente compostos por 12 proteínas (VirB1-VirB11 e VirD4) são tipicamente associados às funções de conjugação bacteriana e transferência de fatores de patogenicidade para células hospedeiras. Mas também, muitas espécies da ordem Xanthomonadales possuem um T4SS associado a matar bactérias. O modelo atual de morte de uma célula-alvo mediada pelo T4SS é baseado na secreção de toxinas denominadas XVIPs ("Xanthomonas VirD4 interacting proteins") ou X-Tfe (Xanthomonadaceae-T4SS effector) no qual cada XVIP/X-Tfe apresenta uma proteína de imunidade cognata denominada X-Tfi (Xanthomonadaceae-T4SS immunity protein). Demonstramos que um XVIP, XAC2609, é secretado através do T4SS de modo que depende de contato célula-célula e do seu domínio XVIPCD ("XVIP conserved domains"). A porção N-terminal de XAC2609 codifica um domínio GH19 que cliva a peptideoglicana de E. coli, mas perde a sua atividade na presença do seu inibidor cognato, o X-Tfi XAC2610. Portanto, XAC2609/XAC2610 formam um par de proteínas efetora/imunidade associado ao T4SS de X. citri. Através de diferentes técnicas de microscopias utilizando a cepa Δxac2610, foi observado que XAC2610 protege o envelope celular de X. citri contra efeitos de autólise celular promovidos pela atividade de XAC2609. Ensaios funcionais baseados nas observações de fenótipos de colônias e de formação de biofilme mostraram que XAC2610 confere imunidade para X. citri contra uma atividade 7 intrínseca de XAC2609. A proteína com o papel de reconhecer os substratos através da interação com os sinais de secreção do T4SS é VirD4. No T4SS de X. citri, existe a hipótese de que o domínio XVIPCD seja o sinal de secreção presente nas XVIPs. Logo, os aspectos bioquímicos e biofísicos da interação VirD4-XVIPCD foram investigados através de experimentos de co-purificação por cromatografia de afinidade e exclusão molecular, RMN e SAXS. Demonstramos que o domínio AAD de VirD4 (VirD4AAD) está associado a interagir especificamente com o domínio XVIPCD de XAC2609 (XAC2609XVIPCD), formando um heterodímero em solução. VirD4AAD é um domínio globular e monomérico e XAC2609XVIPCD é desenovelado mas se enovela concomitante à interação com VirD4AAD. Construções de XAC2609 contendo mutações pontuais no domínio XVIPCD foram utilizadas em ensaios in vivo de secreção pela X. citri e ensaios in vitro de interação com VirD4AAD por titulação monitorada por calorimetria isotérmica (ITC). Através desses experimentos, observamos que uma forte interação entre VirD4AAD-XAC2609XVIPCD é essencial para secreção de XAC2609 via o T4SS. Esses resultados permitem concluir que o domínio XVIPCD é o sinal de secreção dos substratos do T4SS de X. citri e que o AAD confere especificidade à VirD4 por interagir com o XVIPCD. Finalmente, através de ensaios de competições bacterianas entre E. coli e X. citri, foram observados diferentes fenótipos associados à função do T4SS: i) nocautes gênicos das subunidades estruturais VirB5, VirB11 abolem a função do T4SS em X. citri.; ii) nocautes de xac2611, apresentaram uma maior vantagem adaptativa do que a cepa selvagem de X. citri em competições e a expressão epissomal de XAC2611 inibe fortemente a função do T4SS e iii) a atividade ATPásica de VirD4 é essencial para a função do sistema e a expressão de mutantes 8 de VirD4 exerce um fenótipo de dominância negativa sobre a função do T4SS em X. citri
The Type IV secretion System (T4SS) is typically associated with the function of bacterial conjugation and as a pathogenicity factor. T4SSs are normally composed of 12 proteins, VirB1-VirB11 and VirD4. Many species of the order Xanthomonadales possess a T4SS associated with killing bacteria. The current model of the T4SS killing is based on the secretion of toxins denominated XVIPs/X-Tfes (Xanthomonas VirD4 interacting proteins) /(Xanthomonadaceae-T4SS effector) in which each XVIP/X-Tfe has a cognate immunity protein denominated X-Tfi (Xanthomonadaceae-T4SS immunity protein). We demonstrate that an XVIP, XAC2609, is secreted through the T4SS so that it depends on cell-cell contact and its XVIPCD domain ("XVIP conserved domains"). The N-terminal portion of XAC2609 encodes a GH19 domain which cleaves the E. coli peptidoglycan but loses its activity in the presence of its cognate inhibitor, X-Tfi XAC2610. Therefore, XAC2609 /XAC2610 form a pair of effector/immunity proteins associated with X. citri T4SS. By using the X. citri Δxac2610 strain, has been shown through different microscopic techniques that XAC2610 protects the cell envelope of X. citri against the effects of cellular autolysis promoted by XAC2609 activity. Functional assays based on observations of colony phenotypes and biofilm formation has shown that XAC2610 confers immunity to X. citri against an intrinsic activity of XAC2609. VirD4 is the protein that recognizes the substrates through the interaction with the T4SS secretion signals. In the T4SS of X. citri, is hypothesized that the XVIPCD domain is the secretion signal present in the XVIPs. Here, the biochemical and biophysical aspects of the VirD4-XVIPCD interaction were investigated through Pull- Down, Molecular Exclusion Chromatography, NMR and SAXS assays. It has been shown the AAD domain of VirD4 (VirD4AAD) is associated with specifically interacting with the XAC2609XVIPCD domain (XAC2609XVIPCD), forming a heterodimer in solution. VirD4AAD is a globular and monomeric domain while XAC2609XVIPCD is elongated, but upon interaction with VirD4AAD goes through structural compaction process. Constructs of XAC2609 containing point mutations in the XVIPCD domain were used to perform secretion experiments in X. citri and Isothermal titration calorimetry against VirD4AAD. Through these assays, it has been characterized that a strong interaction between VirD4AAD-XAC2609XVIPCD is essential for secretion of XAC2609 via T4SS. Consequently, these results allow concluding that the XVIPCD domain is the secretion signal of X. citri T4SS substrate and the AAD confer specificity to VirD4 by interact with the XVIPCD domains. Finally, bacterial competitions between E. coli and X. citri showed different phenotypes associated with T4SS function: i) virB5, virB11 knockouts abolish the function of T4SS in X. citri.; ii) knockouts of xac2611 exhibited a higher adaptive efficiency than the wild-type X. citri strain in competitions, but the expression of XAC2611 abolishes the function of T4SS in the wild strain of X. citri; iii) The ATPase activity of VirD4 is essential and exerts a negative dominance over the T4SS function in X.citri
Asunto(s)
Xanthomonas/clasificación , Sistemas de Secreción Tipo IV/análisis , Cromatografía de Afinidad/instrumentación , Análisis de Secuencia/métodos , Microscopía/métodosRESUMEN
The diagnosis of invasive aspergillosis remains a challenge. Detection of galactomannan in serum and bronchoalveolar lavage is a useful tool; however due to methodological and economic reasons, the test frequencies of galactomannan assays vary from daily to weekly, which constitute a risk to the patient. In this study, we aimed to evaluate and correlate the performance of the new kit Aspergillus-LFD with the GM-EIA. Aspergillus-LFD kit represents a fast, economical and simple test; showed a good performance and excellent correlation with GM-EIA kit. Given the above, the Aspergillus-LFD is emerging as an alternative to consider in the early diagnosis of invasive aspergillosis.
Asunto(s)
Aspergilosis/diagnóstico , Aspergillus/aislamiento & purificación , Cromatografía de Afinidad/instrumentación , Técnicas para Inmunoenzimas/instrumentación , Mananos/análisis , Juego de Reactivos para Diagnóstico , Biomarcadores/sangre , Chile , Cromatografía de Afinidad/economía , Galactosa/análogos & derivados , Humanos , Técnicas para Inmunoenzimas/economía , Juego de Reactivos para Diagnóstico/economía , Sensibilidad y Especificidad , Factores de TiempoRESUMEN
Introduction: Invasive fungal diseases (IFD) by filamentous fungi are a common cause of morbidity and mortality in immunocompromised patients, especially those with myeloid leukemia. In 2011 a protocol for the rapid diagnosis of IFD by filamentous fungi was implemented in Valparaiso Region. Objectives: To describe cases of IFD by filamentous fungi of the Valparaíso Region, since the implementation of rapid diagnosis and to compare results with the period 2004-2009. Materials and Method: Descriptive and prospective study conducted in two public hospitals: Carlos van Buren at Valparaiso and Gustavo Fricke at Viña del Mar. We selected patients with a diagnosis of filamentous fungal diseases considering the EORTC/MSG criteria. Demographics, underlying diseases, risk factors for EFI, galactomannan (GM) results in blood and bronchoalveolar lavage, cultures and biopsies, treatment and overall lethality rates at 30 days were registered. Results: Eighteen patients were detected, 6 with proven and 12 probable IFD. Nine were diagnosed by GM, 8 by culture and two with both methods. In cases which the agent (9/18) was isolated from Rhizopus oryzae was the most frequent. When comparing overall lethality with the period 2004-2009, there was a reduction of 47.8%, which was statistically significant. Conclusions: Compared to data previously published in the region, demographic and comorbidities of patients with IFD caused by filamentous fungi are similar, however the currently rapid diagnosis protocol has improved survival of patients and lethality experienced overall decrease.
Introducción: la enfermedad fúngica invasora (EFI) por hongos filamentosos es una causa frecuente de morbilidad y mortalidad en pacientes inmunocomprometidos, en especial en aquellos con leucemia mieloide. En el 2011 se implementó en la Región de Valparaíso un protocolo de diagnóstico rápido de la EFI por hongos filamentosos. Objetivos: describir los casos de EFI por hongos filamentosos de la Región de Valparaíso, desde la implementación del diagnóstico rápido y compararlos con el período 2004-2009. Materiales y Método: Estudio descriptivo y prospectivo realizado en los hospitales públicos Carlos van Buren de Valparaíso y Gustavo Fricke de Viña del Mar. Se seleccionaron aquellos pacientes con diagnóstico de EFI por hongos filamentosos considerando los criterios EORTC/MSG. Se obtuvieron datos demográficos, enfermedad de base, factores de riesgo para EFI, resultados de galactomanano (GM), cultivos y biopsias, tratamiento y letalidad global a 30 días. Resultados: Se identificaron 18 pacientes, seis con EFI probadas y 12 probables. Nueve fueron diagnosticados con galactomanano, ocho con cultivos y uno con los dos métodos. En los casos en que se aisló el agente (9/18), Rhizopus oryzae fue el más frecuente. Al comparar la letalidad global con la del período 2004-2009, hubo una reducción de 47,8%, la cual fue estadísticamente significativa. Conclusiones: En relación a lo publicado anteriormente en la región, se conservan las características demográficas y de co-morbilidad de los pacientes con EFI por hongos filamentosos; sin embargo, la introducción del nuevo protocolo de diagnóstico rápido se asoció a una disminución en la letalidad global.
Asunto(s)
Humanos , Aspergilosis/diagnóstico , Juego de Reactivos para Diagnóstico , Aspergillus/aislamiento & purificación , Cromatografía de Afinidad/instrumentación , Técnicas para Inmunoenzimas/instrumentación , Mananos/análisis , Juego de Reactivos para Diagnóstico/economía , Factores de Tiempo , Biomarcadores/sangre , Chile , Cromatografía de Afinidad/economía , Técnicas para Inmunoenzimas/economía , Sensibilidad y EspecificidadRESUMEN
The worldwide production of whey increases by around 186 million tons each year and it is generally considered as a waste, even when several whey proteins have important economic relevance. For its valorization, inexpensive ligands and integrated chromatography methods need to be developed for specific and low-cost protein purification. Here, we describe a novel affinity process with the dye Yellow HE-4R immobilized on Sepharose for bovine lactoferrin purification. This approach based on a low-cost ligand showed an efficient performance for the recovery and purification of bovine lactoferrin directly from whey, with a yield of 71% and a purification factor of 61.
Asunto(s)
Cromatografía de Afinidad/métodos , Lactoferrina/aislamiento & purificación , Proteínas de la Leche/aislamiento & purificación , Animales , Bovinos , Cromatografía de Afinidad/instrumentación , Colorantes/química , Lactoferrina/química , Ligandos , Proteínas de la Leche/química , Proteína de Suero de LecheRESUMEN
BACKGROUND: Rapid diagnostic tests (RDT) for malaria have been demonstrated to be effective and they should replace microscopy in certain areas. METHOD: The cost-effectiveness of five RDT and thick smear microscopy was estimated and compared. Data were collected on Brazilian Extra-Amazon Region. Data sources included the National Malaria Control Programme of the Ministry of Health, the National Healthcare System reimbursement table, laboratory suppliers and scientific literature. The perspective was that of the Brazilian public health system, the analytical horizon was from the start of fever until the diagnostic results provided to patient and the temporal reference was that of year 2010. Two costing methods were produced, based on exclusive-use microscopy or shared-use microscopy. The results were expressed in costs per adequately diagnosed cases in 2010 U.S. dollars. One-way sensitivity analysis was performed considering key model parameters. RESULTS: In the cost-effectiveness analysis with exclusive-use microscopy, the RDT CareStart™ was the most cost-effective diagnostic strategy. Microscopy was the most expensive and most effective, with an additional case adequately diagnosed by microscopy costing US$ 35,550.00 in relation to CareStart™. In opposite, in the cost-effectiveness analysis with shared-use microscopy, the thick smear was extremely cost-effective. Introducing into the analytic model with shared-use microscopy a probability for individual access to the diagnosis, assuming a probability of 100% of access for a public health system user to any RDT and, hypothetically, of 85% of access to microscopy, this test saw its effectiveness reduced and was dominated by the RDT CareStart™. CONCLUSION: The analysis of cost-effectiveness of malaria diagnosis technologies in the Brazilian Extra-Amazon Region depends on the exclusive or shared use of the microscopy. Following the assumptions of this study, shared-use microscopy would be the most cost-effective strategy of the six technologies evaluated. However, if used exclusively for diagnosing malaria, microscopy would be the worst use of resources. Microscopy would not be the most cost-effective strategy, even when structure is shared with other programmes, when the probability of a patient having access to it was reduced. Under these circumstances, the RDT CareStart™ would be the most cost-effective strategy.
Asunto(s)
Cromatografía de Afinidad/economía , Cromatografía de Afinidad/métodos , Malaria/diagnóstico , Malaria/economía , Microscopía/economía , Microscopía/métodos , Parasitología/economía , Parasitología/métodos , Brasil/epidemiología , Cromatografía de Afinidad/instrumentación , Análisis Costo-Beneficio , Técnicas de Apoyo para la Decisión , Árboles de Decisión , Humanos , Malaria/epidemiología , Microscopía/instrumentación , Parasitología/instrumentaciónRESUMEN
In the early 1990s, three research groups simultaneously developed continuous macroporous rod-shaped polymeric systems to eliminate the problem of flow through the interparticle spaces generally presented by the chromatography columns that use particles as filler. The great advantage of those materials, forming a continuous phase rod, is to increase the mass transfer by convective transport, as the mobile phase is forced to go through all means of separation, in contrast to particulate media where the mobile phase flows through the interparticle spaces. Due to their special characteristics, the monolithic polymers are used as base-supports in different separation techniques, those chromatographic processes being the most important and, to a greater extent, those involving the separation of biomolecules as in the case of affinity chromatography. This mini-review reports the contributions of several groups to the development of macroporous monoliths and their modification by immobilization of specific ligands on the products for their application in affinity chromatography.
Asunto(s)
Cromatografía de Afinidad/instrumentación , Ácidos Nucleicos/química , Proteínas/química , Animales , Cromatografía de Afinidad/métodos , Humanos , Ligandos , Porosidad , Dióxido de Silicio/químicaRESUMEN
Monoclonal antibodies (MAbs) have been used for therapies and some analytical procedures as highly purified molecules. Many techniques have been applied and studied, focusing on monoclonal antibodies purification. In this study, an immobilized metal affinity chromatography membrane was developed and evaluated for the purification of anti-TNP IgG(1) mouse MAbs from cell culture supernatant after precipitation with a 50% saturated ammonium sulfate solution. The chelating ligands iminodiacetic acid, carboxymethylated aspartic acid (CM-Asp), nitrilotriacetic acid, and tris (carboxymethyl) ethylenediamine in agarose gels with immobilized Ni(II) and Zn(II) ions were compared for the adsorption and desorption of MAbs. The most promising chelating ligand--CM-Asp--was then coupled to poly(ethylene vinyl alcohol) (PEVA) hollow fiber membranes. According to SDS-PAGE and ELISA analyses, a higher selectivity and a purification factor of 85.9 (fraction eluted at 500 mM Tris) were obtained for IgG(1) using PEVA-CM-Asp-Zn(II). The anti-TNP MAb could be eluted under mild pH conditions causing no loss of antigen binding capacity.
Asunto(s)
Anticuerpos Monoclonales/aislamiento & purificación , Quelantes/química , Cromatografía de Afinidad/métodos , Inmunoglobulina G/aislamiento & purificación , Metales/química , Adsorción , Anticuerpos Monoclonales/química , Ácido Aspártico/química , Cromatografía de Afinidad/instrumentación , Etilenodiaminas/química , Iminoácidos/química , Inmunoglobulina G/química , Ligandos , Membranas Artificiales , Níquel/química , Ácido Nitrilotriacético/química , Propiedades de Superficie , Zinc/químicaRESUMEN
Sunflower trypsin inhibitor-1 (SFTI-1), a natural 14-residue cyclic peptide, and some of its synthetic acyclic variants are potent protease inhibitors displaying peculiar inhibitory profiles. Here we describe the synthesis and use of affinity sorbents prepared by coupling SFTI-1 analogues to agarose resin. Chymotrypsin- and trypsin-like proteases could then be selectively isolated from pancreatin; similarly, other proteases were obtained from distinct biological sources. The binding capacity of [Lys5]-SFTI-1-agarose for trypsin was estimated at over 10 mg/mL of packed gel. SFTI-1-based resins could find application either to improve the performance of current purification protocols or as novel protease-discovery tools in different areas of biological investigation.
Asunto(s)
Cromatografía de Afinidad/métodos , Helianthus/química , Péptidos Cíclicos/química , Proteínas de Plantas/química , Serina Endopeptidasas/aislamiento & purificación , Inhibidores de Tripsina/química , Animales , Cromatografía de Afinidad/instrumentación , Pancreatina/química , Unión Proteica , Resinas Sintéticas/química , Serina Endopeptidasas/química , PorcinosRESUMEN
The purification of IgG from human plasma was studied by comparing two affinity membranes complexed with Ni(II), prepared by coupling iminodiacetic acid (IDA) and Tris(2-aminoethyl)amine (TREN) to poly(ethylenevinyl alcohol), PEVA, hollow fiber membranes. The Ni(II)-TREN-PEVA hollow fiber membrane had lower capacity for human IgG than the complex Ni(II)-IDA-PEVA, but with similar selectivity. The IgG in peak fractions eluted from the Ni(II)-IDA-PEVA with a stepwise concentration gradient of Tris-HCl pH 7.0 (100-700 mM) reached a purity of 98% (based on IgG, IgM, IgA, albumin, and transferrin nephelometric analysis). Adsorption IgG data at different temperatures (4-37 degrees C) were analyzed using Langmuir model resulting in a calculated maximum capacity at 25 degrees C of 204.6 mg of IgG/g of dry membrane. Decrease in Kd with increasing temperature (1.7x10(-5) to 5.3x10(-6) M) indicated an increase in affinity with increased temperature. The positive value of enthalpy change (26.2 kJ/mol) indicated that the adsorption of IgG in affinity membrane is endothermic. Therefore, lower temperature induces adsorption as verified experimentally.
Asunto(s)
Cromatografía de Afinidad/métodos , Etilenodiaminas/química , Iminoácidos/química , Inmunoglobulina G/aislamiento & purificación , Níquel/química , Adsorción , Tampones (Química) , Quelantes/química , Cromatografía de Afinidad/instrumentación , Humanos , TemperaturaRESUMEN
The properties of an adsorbent and the parameters in an adsorption process affect the resolution of chromatographic purifications. This is reflected in the elution profile, which shows the relative affinity of different proteins for a specific adsorbent. In the work presented here, elution profiles for trypsin inhibitor were used to study the effects of the concentration of trypsin inhibitor, ionic strength of the protein solution, slope of the elution gradient, and the regeneration treatment of the chromatography column on the selectivity of the adsorbent Cellufine Chelate-Cu(II)(ida). Cytochrome c was used as a reference protein. Variations in the concentrations of trypsin inhibitor and in the ionic strength of the buffered solution did not have any effects on the elution profile. On the other hand, changes in the slope of the pH gradient used for elution caused shifting of the elution peaks toward lower values of the elution volume, resulting in the best strategy to modify the elution profile of the system. Finally, using a constant slope pH gradient of elution, the variation of the selectivity of the adsorbent for trypsin inhibitor when subjected to cleaning treatments with 0.5 N NaOH was studied. Appropriate cleaning practices used in industry were followed. The adsorbent showed only a slight tendency for resolution loss in the order of 2 x 10(-4) days(-1). The results presented here show a good stability of the adsorbent when compared to other biospecific adsorbents commonly used.
Asunto(s)
Cromatografía de Afinidad/métodos , Inhibidor de la Tripsina de Soja de Kunitz/aislamiento & purificación , Quelantes/química , Cromatografía de Afinidad/instrumentación , Cobre/química , Grupo Citocromo c/aislamiento & purificación , Concentración de Iones de Hidrógeno , Concentración OsmolarRESUMEN
Foi investigada a concentraçäo do interferon humano de membranas amnióticas (IFN-MA) por precipitaçäo através de métodos químicos. O IFN-MA foi produzido em âmnios infectados com o vírus da doença de Newcastle em meio contendo diferentes concentraçöes de soro. A atividade anti-vírica das preparaçöes foi titulada em células Vero infectadas com o vírus da encefalomiocardite de camundongo ou o vírus Sindbis. A precipitaçäo de IFN-MA, consideradas baixas. Empregando-se sulfato de âmnio em preparaçöes com 1//de soro, pode-se recuperar quantidades acima de 60//. O método mais adequado de concentraçäo de IFN-MA contendo 1//de soro foi a precipitaçäo com ácido tricloroactico e ressuspenso do matrial com tampäo clorto pH2, com recuperaçöes em torno de 100//da atividade. As tentativas de concentrar IFN-MA preparado sem soro por estes métodos näo permitiu uma precipitaçäo adequada