Relation factor: a new strategy for quality control in the determination of pesticides in environmental aqueous matrices.

The effects promoted by environmental aqueous matrices on pesticide determinations have been assessed, and for the first time, a simple, low-cost and efficient strategy for the correction of analytical results has been determined. This method can be useful as a parameter of quality control in a quality assurance programs. Evaluation of the matrix effect showed that environmental aqueous matrices, e.g., estuarine water, promote a distinctive and significant effect on the determination of pesticides. The picloram, atrazine and methyl parathion pesticides suffered the smallest effects promoted by the estuarine matrix, whereas chlorpyrifos and cypermethrin suffer a significant effect. For picloram, the matrix effect was a function of its physiochemical properties. However, for atrazine, methyl parathion, chlorpyrifos and cypermethrin, the matrix effect was promoted by environmental matrix components. As strategy for analytical quality control, it has been determined that there are relation factors (RFs) between pesticides and the selected surrogates standards. These RFs are not altered by the complexities and compositions of simple and complex aqueous matrices. Predetermined RFs was applied to the picloram, atrazine and methyl parathion assessment in a real sample from the estuary of the Jaguaribe River, and the results showed that when no quality control was applied, the concentration levels would be underestimated, leading to incorrect results and inaccurate conclusions.

Genotypic characteristics of HIV type 1 based on gp120 hypervariable region 3 of isolates from Southern Brazil.

The aim of this study was to investigate HIV-1 molecular diversity and the epidemiological profile of HIV-1-infected patients from Ribeirão Preto, Brazil. A nested PCR followed by sequencing of a 302-base pair fragment of the env gene (C2-V3 region) was performed in samples from HIV-1-positive patients. A total of 45 sequences were aligned with final manual adjustments. The phylogenetic analyses showed a higher prevalence of HIV-1 subtype B in the studied population (97.8%) with only one sample yielding an F1 subtype. The viral genotyping prediction showed that CCR5 tropism was the most prevalent in the studied cohort. Geno2pheno analysis showed that R5 and CXCR4 prediction were 69% and 31%, respectively. There was no statistical significance, either in viral load or in CD4(+) T cell count when R5 and X4 prediction groups were compared. Moreover, the GPGR tetramer was the most common V3 loop core motif identified in the HIV-1 strains studied (34.1%) followed by GWGR, identified in 18.1% of the samples. The high level of B subtype in this Brazilian population reinforces the nature of the HIV epidemic in Brazil, and corroborates previous data obtained in the Brazilian HIV-infected population.

Combined use of the polymerase chain reaction and detection of adenosine deaminase activity on pleural fluid improves the rate of diagnosis of pleural tuberculosis.

STUDY OBJECTIVES: Evaluation of the combined use of polymerase chain reaction (PCR) and adenosine deaminase (ADA) activity on the diagnosis of pleural tuberculosis (pTB) in a region of high prevalence of tuberculosis. PATIENTS: PCR and determination of ADA activity were performed on the pleural fluid of every patient presenting with pleural effusion suspected to be associated with tuberculosis. The case definition of pTB involved parameters including the combination of clinical and radiologic findings; biochemical, microbiologic, and cytologic examination of the pleural fluid; and the histopathologic findings of pleural fragments obtained by biopsy. The diagnosis of pTB was confirmed in any patient presenting with positive culture findings of Mycobacterium tuberculosis, either on the pleural fluid or other biological material, or the presence of histopathologic findings suggestive of pTB on pleural biopsy, and also, in the absence of negative laboratory results, those patients with clinical improvement after empirical treatment. RESULTS: We studied 45 patients with pleural effusion. Of these, 16 patients met the diagnosis of pTB by our broad case definition. PCR findings were positive in six patients. The reaction was also positive in a patient whose diagnosis of tuberculosis could not be confirmed. ADA activity was considered positive in 11 patients with pTB. The combined use of PCR and ADA activity confirmed pTB in 14 patients; however, when analyzed in combination with the conventional methods, diagnosis of pTB was achieved in all 16 patients. CONCLUSION: Our results show that, even in a highly endemic area, neither PCR nor ADA activity should be relied on as a single test that substitutes for the diagnostic methods already available, but rather they should be used as an extra tool in the diagnosis of pTB. The combined analysis of PCR and ADA activity, however, is a very useful diagnostic approach to achieve a more rapid and precise diagnosis in the cases of pTB.

Pancitopenia transitóoria induzida por parvovírus B19 em criança portadora de esferocitose hereditária / Transient pancytopenia induced by parvovirus B19 in a child with hereditary sherocytosis

Objetivo: Relatar a ocorrência de pancitopenia transitória, decorrente de infecção pelo parvovírus B19, em um paciente portador de anemia hemolíitica hereditária e comentar a importância do diagnóstico desta infecção. Métodos: Relato de caso clínico acompanhado pelos autores, diagnosticado sorologicamente e pelo método da reação em cadeia da polimerase (PCR), e revisão da literatura. Resultados: Menino de 12 anos, portador de esferocitose hereditária, apresentando quadro infeccioso inespecífico seguido de pancitopenia grave, transitória, com diagnóstico de infecção por parvovírus B19. Conclusões: O diagnóstico da infecção por parvovírus B19 é de particular importância em hematologia, principalmente quando estão presentes algumas condições mórbitas, entre elas as anemias hemolíticas hereditárias, sendo o método de PCR útil por permitir rapidez e boa sensibilidade no diagnóstico específico desta patologia