Distorción del mapa anzimático renal en ratas tratadas con menadiona (vitamina k3) / Distortion of the map enzyme renal in rats treaty with menadiona (vitamin k3)

La menadiona (2-metil-1,4-naftoquinona, vitamina k3) es una quinona, cuya toxicidad se atribuye al estrés oxidativo inducido por el ciclaje redox de esta droga en las células. Se ha señalado que el riñon es más sensible a la menadiona que otros órganos, incluyendo el corazón y el hígado. El propósito de este estudio es investigar, en ratas blancas, los efectos tóxicos de la menadiona sobre la actividad renal de las siguientes eszimas: deshidrogenasa láctica, maltasa ácida y alanina y aspartato aminotransferasas. La administración de menadiona a dosis elevadas determinó un grado variable de lesiones renales y un incremento significativo (p<0.05) en la actividad de todas las enzimas valoradas en comparación con los controles no tratados. El daño renal depende de las dosis administradas de vitamina K3, y puede ser debido a la liberación de las proteasas ácidas desde los lisosomas, después de la destrucción de sus membranas por el estrés oxidativo inducido por la quinona. Este daño, a su vez determina el incremento en la actividad de las otras enzimas estudiadas. En conclusión, la vitamina K3 a dosis elevadas, determina cambios importantes en las actividades enzimáticas renales

Optimum phase-behavior formulation of surfactant/oil/water systems for the determination of chromium in heavy crude oil and in bitumen-in-water emulsion.

An "oil in water" formulation was optimized to determine chromium in heavy crude oil (HCO) and bitumen-in-water emulsion (Orimulsion-400(R)) samples by transversally heated electrothermal atomic absorption spectrometry (TH-ET AAS) using Zeeman effect background correction. The optimum proportion of the oil-water mixture ratio was 7:3 v/v (70 ml of oil as the internal phase) with a non-ionic surfactant concentration (Intan-100) in the emulsion of 0.2% w/w. Chromium was determined in different crude oil samples after dilution of the emulsions 1:9 v/v with a 0.2% w/w solution of surfactant in order to further reduce the viscosity from 100 to 1.6 cP and at the same time to bring the concentration of chromium within the working range of the ET AAS technique. The calibration graph was linear from 1.7 to 100 mug Cr l(-1). The sensitivity was of 0.0069 s l mug(-1), the characteristic mass (m(o)) was of 5.7 pg per 0.0044 s and the detection limit (3sigma) was of 0.52 mug l(-1). The relative standard deviation of the method, evaluated by replicate analyses of three crude oil samples varied in all cases between 1.5 and 2.6%. Recovery studies were performed on four Venezuelan crude oils, and the average chromium recovery values varied between 95.9-104.8, 90.6-107.6, 95.6-104.0 and 98.8-103.9% for the Cerro Negro, Crudo Hamaca and Boscán crude oils and for the Orimulsión(R)-400, respectively. The results obtained in this work for the Cerro Negro, Crudo Hamaca and Boscán crude oils and for the Orimulsión(R)-400 following the proposed procedure were of 0.448+/-0.008, 0.338+/-0.004 0.524+/-0.021 and 0.174+/-0.008 mg Cr l(-1), respectively, which were in good agreement with the values obtained by a tedious recommended standard procedure (respectively: 0.470+/-0.05, 0.335+/-0.080, 0.570+/-0.021 and 0.173+/-0.009 mg Cr l(-1)).