Study of Blood Porphyrin Spectral Profile for Diagnosis of Chronic Renal Failure

The progression to end-stage renal failure is independent of the initial pathogenic mechanism. Metabolic acidosis is a common consequence of chronic renal failure that results from inadequate ammonium excretion and decreased tubular bicarbonate reabsorption. Protoporphyrin IX (PpIX) is the immediate metabolic precursor of the heme molecule. the purpose of this study was to evaluate the levels of erythrocytes protoporphyrin IX at an animal model during progressive renal disease. A total of 36 eight-week-old male Wistar rats were divided into six groups: Normal, 4 and 8 weeks after 5/6 nephrectomy (NX). Renal function was evaluated by creatinine clearance and plasma creatinine levels. the autofluorescence of erythrocytes porphyrin of healthy and NX rats was analyzed using fluorescence spectroscopy. Emission spectra were obtained by exciting the samples at 405 nm. Significant differences between normal and NX rats autofluorescence shape occurred in the 600-700 nm spectral region. A correlation was observed between emission band intensity at 635 nm and progression of renal disease.IPEN CNEN SP, São Paulo, BrazilUniv São Paulo, Inst Fis, BR-01498 São Paulo, BrazilUNIFESP EPM, Disciplina Nefrol, Dept Med, São Paulo, BrazilUNIFESP EPM, Disciplina Nefrol, Dept Med, São Paulo, BrazilWeb of Scienc

Inter-domain interactions in charged lipid monolayers

Phase coexistence is common in model biomembranes with the presence of domains formed by lipids in a dense phase state modulating lateral diffusion of species through hydrodynamic and electrostatic interactions. In this study, interdomain interactions in monolayers of charged surfactants were analyzed and compared with neutral systems. Interactions were investigated at different interdomain distances and by varying the ionic strength (I) of the subphase. At low percentages of condensed area (%Ac), i.e., high interdomain distances, domains were approximated as point charges or dipoles, and a comparison between the simulated and experimental results was made. At high %Ac, domains were arranged in a distorted hexagonal lattice, and the energy of a domain around its equilibrium position in the lattice was modeled using a harmonic potential and the spring constant determined. On subphases of high I, charged domains interacted in a manner similar to neutral domains with domain motion being precluded at high percentages of condensed area. At low I, a higher interdomain repulsion was observed along with a lower domain motion and, therefore, a higher apparent viscosity at comparable %Ac. Interestingly, this effect was observed at conditions where the Debye-Hückel length was still 2 orders lower than the interdomain distances. © 2013 American Chemical Society.Fil: Caruso, Benjamin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; ArgentinaFil: Villarreal, Marcos Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Reinaudi, Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Wilke, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; Argentin