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ABSTRACT Objective: To develop a rapid method for analysing polyphenols, which are potentially active antioxidants against neonatal oxidative stress, from small human milk (HM) volumes. Methods: Acid and alkaline extractions were compared using two dyes: Folin-Ciocalteu and Fast Blue BB. Linearity, sensitivity, recovery percentage, polyphenol content, precision, and stability were assessed in 14 HM samples and compared using the Kruskal-Wallis H test (p<0.05). The best technique was applied to 284 HM samples to determine their polyphenolic content and its association with maternal diet by multifactorial linear regression. Results: Acidic extraction successfully recovered the gallic acid reference standard, whereas alkaline extraction overestimated it. Calibration curves for all methods were linear (R2>0.96) up to 500 mg/L. All bicarbonate-based Folin-Ciocalteu methods assayed were stable and repeatable, whereas Fast Blue BB-based variants were not. HM polyphenols (mean=94.68 mg/L) positively correlated to the dietary intake of hydroxycinnamic acids, the most consumed polyphenolic family in this population. Conclusions: A bicarbonate-based Folin-Ciocalteu micromethod allowed the accurate determination of polyphenols in HM, which might be useful for translational research settings and HM banks.
RESUMO Objetivo: Desenvolver um método rápido para analisar polifenóis, que são antioxidantes potencialmente ativos contra o estresse oxidativo neonatal, em pequenos volumes de leite humano (LH). Métodos: Foram comparadas extrações ácidas e alcalinas usando dois corantes: Folin-Ciocalteu e Fast Blue BB. Foram avaliadas variáveis como linearidade, sensibilidade, percentagem de recuperação, teor de polifenóis, precisão e estabilidade em 14 amostras de LH, comparadas usando o teste de Kruskal-Wallis H (p<0,05). A melhor técnica foi aplicada a 284 amostras de LH para determinar seu teor polifenólico e sua associação com a dieta materna por regressão linear multifatorial. Resultados: A extração ácida recuperou com sucesso o padrão de referência do ácido gálico, enquanto a extração alcalina o superestimou. As curvas de calibração para todos os métodos foram lineares (R2>0,96) até os 500 mg/L. Todos os métodos testados baseados em Folin-Ciocalteu com bicarbonato foram estáveis e repetíveis, enquanto as variantes baseadas em Fast Blue BB não. Os polifenóis do HM (média=94,68 mg/L) correlacionaram-se positivamente com a ingestão dietética de ácidos hidroxicinâmicos, a família de polifenóis mais consumida nesta população. Conclusões: Um micrométodo baseado em bicarbonato de Folin-Ciocalteu permitiu a determinação precisa de polifenóis no HM, o que pode ser útil para configurações de pesquisa translacional e bancos de HM.
ABSTRACT
Objective To prepare the trueness verification materials of C-reactive protein (CRP) and evaluate its homogeneity, stability and commutability. Methods The high and low CRP concentrations trueness verification materials were from patient leftover sera which were pooled, mixed thoroughly, filtered and aliquoted. The homogeneity, stability and commutability of these materials were evaluated according to CNAS(China National Accreditation Service for Conformity Assessment, CNAS)-GL29:2010 "Reference materials-General and statistical principles for certification (ISO Guide35:2006)"and the Clinical and Laboratory Standards Institute (CLSI) EP30A. The trueness verification materials were used to evaluate the commutability in 10 clinical CRP detection systems, using forty-five patients' leftover sera with different CRP concentration evaluated by Deming regression in EP30A of CLSI. Meanwhile, the commutability of dilution series of ERM DA-474/IFCC were evaluated using the same method. Results A total of two CRP concentration level trueness verification materials were prepared, with high and low concentration levels of 754 and 743 vials, 1 ml each, respectively. The preparation showed good homogeneity (F<F0.05(14,30);On the condition of room temperature, 2-8 ℃ and -80 ℃, these materials were stable for 7 days and 44 months respectively, the slope of the linear equation of | b1 | less than t0.95,n-2 · s(b1), there was no statistically significant difference between the slope and zero, the stability is satisfied. The materials and the dilution series of ERM-DA 474/IFCC also showed good commutability among patient sera in 10 systems. Conclusions The trueness verification materials of C-reactive protein (CRP) showed good homogeneity, stability and commutability. The dilution series ERM DA-474/IFCC also have good commutability. These provided experimental support for the value transfer and application of the trueness verification materials .
ABSTRACT
Objetivo: O presente estudo teve como objetivo determinar e comparar o limiar de positividade e a sensibilidade dos métodos de centrífugo-flutuação em sulfato de zinco (Faust et al.) e sedimentação espontânea (Lutz) para o diagnóstico de cistos de Giardia duodenalis. Métodos: Para obtenção de amostras fecais com quantidades conhecidas de cistos de G. duodenalis, amostras positivas para o parasito foram purificadas e quantificadas, e posteriormente alíquotas com diferentes quantidades foram adicionadas a amostras fecais negativas para parasitos. Após a contaminação de oito amostras negativas com quantidades variando entre 1.000 e 200.000 cistos por grama de fezes (c/g/f), as mesmas foram submetidas aos métodos de Faust et al. e Lutz, onde o primeiro se mostrou mais sensível para a detecção de cistos de G. duodenalis. Resultados: O limiar de positividade do método de Faust et al. foi de 11.000 c/g/f, e do método de Lutz foi de 100.000 c/g/f, portanto, cargas parasitárias inferiores a esses limiares levariam a resultados falso-negativos. Conclusão: O método de Lutz não é adequado para o diagnóstico de giardíase, portanto deve ser sempre utilizado em conjunto com o método de Faust et al.
Objective: The present study aimed to determine and compare the positivity threshold and sensitivity of the methods of zinc sulfate centrifugal flotation (Faust et al.) and spontaneous sedimentation (Lutz) for the diagnosis of Giardia duodenalis. Methods: To obtain fecal samples containing known amounts of G. duodenalis cysts, the samples with the parasite were purified and quantified, then aliquots with different amounts were added to fecal samples negative for parasites. After the contamination of eight negative samples with amounts ranging between 1.000 and 200.000 cysts per gram of feces, they were subjected to methods of Faust et al. and Lutz, where the first was more sensitive for the detection of G. duodenalis cysts. Results: The positivity threshold of the method of Faust et al. was 11.000 c/g/f, and the method of Lutz was 100.000 c/g/f, so parasitic loads below those thresholds would lead to false-negative results. Conclusion: The method of Lutz is not suitable for the diagnosis of giardiasis, therefore must always be associated with the method Faust et al.
Subject(s)
Humans , Parasitic Diseases/diagnosis , Sensitivity and Specificity , Giardia lamblia , Analytic Sample Preparation Methods , GiardiasisABSTRACT
Fundamento: la principal causa para el cáncer cervico uterino es el papilomavirus humano de alto riesgo. No existen antecedentes de estudios moleculares para la tipificación de papilomavirus humano en la población de Camagüey. La reacción en cadena de la polimerasa es una técnica de Biología Molecular que se ha usado desde siempre para el diagnóstico clínico; esta permite confirmar la presencia del ADN del Papilomavirus en el ADN total extraído a partir de muestras de pacientes con cáncer de cuello uterino. Objetivo: demostrar por primera vez los genotipos papilomavirus humano de alto riesgo circulantes, que causan cáncer de cuello uterino en la población femenina de Camagüey, Cuba. Métodos: se realizó un estudio analítico prospectivo donde se estudiaron 22 pacientes femeninas de la provincia de Camagüey, que fueron atendidas en la consulta de Patología de cuello del Hospital Ginecoobstétrico. La identificación y tipificación de los genotipos papilomavirus humano se realizó mediante el procedimiento molecular polimorfismo de longitud en los fragmentos de restricción. Resultados: el 63, 6 % de los pacientes presentaron lesiones tipo exofítica, el 4, 5 % endofítica y el 31, 8 % de otros tipos. Este estudio confirmó que los genotipos papilomavirus humanos de alto riesgo circulantes en la provincia Camagüey son los genotipos 16 y 31, donde el más frecuente fue el genotipo 16. Conclusiones: la presente investigación constituye el primer reporte de un estudio molecular de papilomavirus humanos a partir de muestras de pacientes con cáncer de cuello uterino en la provincia de Camagüey, Cuba. Estos resultados, junto a los obtenidos por otros autores, tienen una contribución importante en el diseño de preparados vacunales preventivos o terapéuticos, cada vez más efectivo hacia una solución anticipada para el cáncer de cuello uterino en Cuba.
Background: it is demonstrated that the main cause of cervical cancer is high risk humanp virus. There is no precedent of molecular studies for the typing of Human Papilloma Virus in the population of Camagüey. Polymerase chain reaction is Molecular Biology technique that has been used traditionally for the clinical diagnosis and other purposes. This technique allows confirming the presence of papillomavirus´DNA in the total extracted DNA, from samples of patients with cervical cancer. Objective: to demonstrate for the first time existing high-risk human papilloma virus genotypes that cause cervical cancer in female population of Camagüey, Cuba. Methods: a prospective analytic study was conducted, in which 22 female patients of the province of Camagüey were studied. They received medical attention at Ana Betancourt Hospital. Identification and typing of the Human Papilloma Virus genotypes was carried through the molecular procedure Restriction Fragment Length Polymorphism. Results: patients who presented exophytic lesions accounted for 63, 6%, 4, 5 % had endophytic type, and 31, 8 % presented other types. This study confirmed that high-risk Human Papilloma Virus genotypes existing in the province of Camagüey are genotypes 16 and 31, and the most frequent is 16. Conclusions: this research is the first report of a molecular study of Human Papilloma Virus from samples of patients with cervical cancer in the province of Camagüey, Cuba. These results, along with the ones obtained by other authors, make an important contribution in the design of the increasingly effective therapeutic and preventive vaccine to an anticipated solution to cervical cancer in Cuba.