Acid-base status and renal acid excretion were studied in the Dahl/Rapp salt-sensitive (S) rat and its genetically salt-resistant counterpart (R). S rats developed hypertension while on a very high salt diet (8%) and while on a more physiological salt diet (1%) and remained normotensive while on a very low salt diet (0.08%). Under the high salt diet, intracellular pH measured in freshly isolated thymic lymphocytes using 2',7'-bis (carboxyethyl)-5 (6)-carboxyfluorescein acetomethyl ester, a pH-sensitive dye, was lower in S than in R rats both when measured in the presence of HCO3/CO2 (7.32±0.02 vs. 7.38±0.02, respectively, P < 0.05) and in its absence (7.18±0.04 vs. 7.27±0.02, respectively, P < 0.05). Under the high salt diet, net acid excretion was higher in S than R rats (1,777±111 vs. 1,017±73 gEq/24 h per 100 g body wt, respectively, P < 0.001), and this difference was due to higher rates of both titratable acid and ammonium excretion. Directionally similar differences in intracellular pH and net acid excretion between S and R rats were also observed in salt-restricted animals. In S and R rats placed on a normal salt intake (1%) and strictly pair-fed to control food intake as a determinant of dietary acid, net acid excretion was also higher in S than in R rats (562±27 vs. 329±21 ,uEq/24 h per 100 g, respectively, P < 0.01). No significant difference in either blood pH or bicarbonate levels were found between S and R rats on either the 0.08%, 1%, or 8% salt diets. We conclude that renal acid excretion is augmented in the salt-sensitive Dahl/Rapp rat. Enhanced renal acid excretion may be a marker of increased acid production by cells from subjects with salt-sensitive hypertension. (J. Clin. Invest. 1993. 91:2178-2184 Key words: saltsensitive hypertension * acid excretion * intracellular pH -Na+ / H + antiporter * acid base

Sorbic (SOR) and benzoic (BEN) acids were determined in fruit juice samples by using a net analyte signal-based methodology named HLA/GO (an hybrid linear analysis presented by Goicoechea and Olivieri) applied to spectroscopic signals. The calibration set was built with several fruit juices in order to take into account the natural variability and concentrations of both analytes covering the range usually present in commercial samples. Relative errors of prediction (REP %) of 3.6 and 5.2% were calculated for SOR and BEN respectively. Several figures of merit were calculated-sensitivity, selectivity, analytical sensitivity, and limit of detection. The method is quantitative, with reasonably good recoveries and excellent precision (less than 1%). Wavelength selection was applied, based on the concept of net analyte signal regression, and it allowed us to improve the method performance in samples containing non-modelled interferences, e.g. fruit juices different to those used to build the calibration model.

No abstract

No abstract

La necesidad de producir más alimentos ha llevado al aumento del uso de pesticidas, entre ellos glifosato, el cual es ampliamente empleado en la producción de soja transgénica. Esto ha implicado que crezcan los casos de intoxicaciones y contaminación de recursos naturales. Por tal motivo los entes gubernamentales han formulado instrucciones de manipulación y de descarte de los envases comerciales. El objetivo del presente trabajo fue evaluar la capacidad de Candida tropicalis LMFIQ 703 para disminuir la concentración de glifosato en el tercer enjuague de bidones y así reducir el riesgo de impacto ambiental adverso que producen los residuos de pesticida en los envases vacíos almacenados por largos periodos de tiempo. Se sembraron suspensiones de levadura sin adaptación, en soluciones de Credit® Amonio (Ingrediente activo: sal amónica de la N-fosfonometil glicina) con concentración conocida (similar a la del tercer enjuague). Se incubó a 28°C durante 28 días y se realizó el recuento microbiológico de colonias de levadura cada 7 días. La determinación de la concentración de glifosato se hizo por fluorimetría con calibración multivariada y HPLC. Las levaduras se mantuvieron viables durante todo el experimento, con una disminución inicial por adaptación y una concentración final similar a la inicial. Los resultados de la cuantificación de glifosato a través de fluorescencia y calibración multivariada, aprovechando la ventaja de segundo orden del algoritmo MCR-ALS resultaron comparables con los obtenidos por el método de referencia (HPLC). Se puede concluir que la biorremediación propuesta fue eficiente ya que la concentración de glifosato disminuyó un 39%.

No abstract

No abstract

No abstract