Haptoglobin gene subtypes in three Brazilian population groups of different ethnicities

Haptoglobin is a plasma hemoglobin-binding protein that limits iron loss during normal erythrocyte turnover and hemolysis, thereby preventing oxidative damage mediated by iron excess in the circulation. Haptoglobin polymorphism in humans, characterized by the Hp(*1) and Hp (*2) alleles, results in distinct phenotypes known as Hp1-1, Hp2-1 and Hp2-2, whose frequencies vary according to the ethnic origin of the population. The Hp(*1) allele has two subtypes, Hp (*1F) and Hp (*1S) , that also vary in their frequencies among populations worldwide. In this work, we examined the distribution frequencies of haptoglobin subtypes in three Brazilian population groups of different ethnicities. The haptoglobin genotypes of Kayabi Amerindians (n = 56), Kalunga Afro-descendants (n = 70) and an urban population (n = 132) were determined by allele-specific PCR. The Hp(*1F) allele frequency was highest in Kalunga (29.3%) and lowest in Kayabi (2.6%). The Hp(*1F)/Hp(*1S) allele frequency ratios were 0.6, 1.0 and 0.26 for the Kayabi, Kalunga and urban populations, respectively. This variation was attributable largely to the Hp(*1F) allele. However, despite the large variation in Hp(*1F) frequencies, results of F (ST) (0.0291) indicated slight genetic differentiation among subpopulations of the general Brazilian population studied here. This is the first Brazilian report of variations in the Hp(*1F) and Hp(*1S) frequencies among non-Amerindian Brazilians.     

Development of immunosensors for the analysis of 1-naphthol in organic media

Immunosensor systems have been developed for the rapid determination of 1-naphthol. In this work, the comparison of performance of immunosensors working in aqueous and organic media was done. Direct, indirect and capture formats were studied. Immunoreagents were immobilized on controlled pore glass (CPG), hidroxysuccinimide agarose gel or on azlactone Protein A/G supports. The Protein A/G-based sensor showed the best performance. In aqueous media, a LOD of 16.2 microg l(-1) and a DR of 33.7-586.6 microg l(-1) were achieved employing Tween 20 at a concentration ranging from 0.01 to 0.05% v/v. Maximum sensitivity was reached with 0.025% of surfactant. Binary mixtures of methanol or acetonitrile with aqueous buffer and ternary mixtures of methanol/isopropanol or ethyl acetate/methanol with the same buffer were studied as organic media. The mixture 50% MeOH-50% 20 mM sodium phosphate, pH 8, with 0.05% (v/v) Tween 20 resulted to be the best. A detection limit of 12.0 microg l(-1) and a dynamic range of 53.6-17,756.0 microg l(-1) were reached. The recycling of Protein A/G-based sensor working in this media was about 300 assays. Preconcentration factors around 250 were achieved using methanol as extracting solvent. It has been demonstrated that the technique can be successful in carrying out the analysis of low solubility in water analytes, such as 1-naphthol. The sensors developed can use higher concentrations of organic solvent (up to 50% methanol) compared to ELISA. On the other hand, the advantage of preconcentration can also be taken for the use of the same procedure as recommended for standard sample treatments.     

HIV-Associated Cryptococcal Meningitis Patients Treated with Amphotericin B Deoxycholate Plus Flucytosine under Routine Care Conditions in a Referral Center in São Paulo,Brazil

Mycopathologia - Cryptococcal meningitis remains a common cause of mortality in low- and middle-income countries, where amphotericin B deoxycholate (amphotericin) plus fluconazole is the most...