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Resano M.,University of Zaragoza | Rello L.,University of Zaragoza | Rello L.,Miguel Servet Universitary Hospital | Florez M.,University of Zaragoza | Belarra M.A.,University of Zaragoza
Spectrochimica Acta - Part B Atomic Spectroscopy

This paper explores the potential of commercially available high-resolution continuum source graphite furnace atomic absorption spectrometry instrumentation for the simultaneous or sequential monitoring of various atomic lines, in an attempt to highlight the analytical advantages that can be derived from this strategy. In particular, it is demonstrated how i) the monitoring of multiplets may allow for the simple expansion of the linear range, as shown for the measurement of Ni using the triplet located in the vicinity of 234.6 nm; ii) the use of a suitable internal standard may permit improving the precision and help in correcting for matrix-effects, as proved for the monitoring of Ni in different biological samples; iii) direct and multi-element analysis of solid samples may be feasible on some occasions, either by monitoring various atomic lines that are sufficiently close (truly simultaneous monitoring, as demonstrated in the determination of Co, Fe and Ni in NIST 1566a Oyster tissue) or, alternatively, by opting for a selective and sequential atomization of the elements of interest during every single replicate. Determination of Cd and Ni in BCR 679 White cabbage is attempted using both approaches, which permits confirming that both methods can offer very similar and satisfactory results. However, it is important to stress that the second approach provides more flexibility, since analysis is no longer limited to those elements that show very close atomic lines (closer than 0.3 nm in the ultraviolet region) with a sensitivity ratio similar to the concentration ratio of the analytes in the samples investigated. © 2011 Elsevier B.V. Source

Aramendia M.,Centro Universitario Of La Defensa Academia General Militar Of Zaragoza | Aramendia M.,Aragon Institute of Engineering Research | Rello L.,Miguel Servet Universitary Hospital | Berail S.,University of Pau and Pays de lAdour | And 3 more authors.
Journal of Analytical Atomic Spectrometry

This work describes a novel procedure based on the use of a 1030 nm femtosecond (fs) laser ablation (LA) device operating at a high repetition rate (30000 Hz) coupled to a sector field-inductively coupled plasma-mass spectrometer (ICP-MS), enabling the complete ablation of dried blood spot (DBS) specimens in a reasonable time (200 s for samples of 5 μL). The integration of the complete signal obtained, in combination with the use of Pt as an internal standard (which can be added to the clinical filter paper prior to the blood deposition, ensuring compatibility with unsupervised sample collection schemes), permits obtaining an analytical response that is independent of the particular characteristics of every sample. On the basis of this methodology, an analytical method was developed for the direct determination of several elements (Cd, Co, Cu and Pb) in four blood reference materials as well as in three real samples, providing accurate results in all cases evaluated, at concentration levels ranging from 0.1 to hundreds of μg L-1. Detection limits of 0.043 (Cd), 0.42 (Co), 0.54 (Cu), and 0.040 (Pb) μg L-1 are achieved, and precision values most often range between 3 and 9% RSD. Finally, the potential to couple the LA device simultaneously to a multicollector-ICP-MS and a sector field-ICP-MS unit by split-flow is also demonstrated, thus allowing us to obtain both elemental (Co, Cu, Cd and Pb) and isotopic (Cu isotopic composition) information from every particular DBS, and therefore maximizing the amount of information that can be drawn from a single DBS specimen. Still, the precision of the approach is limited at this point, as RSD values of approx. 1500 ppm and delta variations of almost 4‰ were observed for five DBS specimens created from the same blood sample. This journal is © The Royal Society of Chemistry. Source

Rello L.,University of Zaragoza | Rello L.,Miguel Servet Universitary Hospital | Lapena A.C.,University of Zaragoza | Aramendia M.,Centro Universitario Of La Defensa Academia General Militar Of Zaragoza | And 2 more authors.
Spectrochimica Acta - Part B Atomic Spectroscopy

Home-based collection protocols for clinical specimens are actively pursued as a means of improving life quality of patients that require frequent controls, such as patients with metallic prosthesis, for whom monitoring the evolution of Mo and Ti in biological fluids may play a decisive role to detect prosthesis mal-functioning. The collection of biological fluids on clinical filter papers provides a simple way to implement these protocols. This work explores the potential of solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry for the simultaneous and direct determination of Mo and Ti in urine, after its deposition onto clinical filter paper, giving rise to a dried urine spot. The approach used for depositing the sample was found crucial to develop a quantitative method, since the filter paper acts as a chromatographic support and produces a differential distribution of the target analytes. Furthermore, the high spreading of urine onto a filter paper results in a small amount of urine per surface unit, and thus, ultimately, in lack of sensitivity. In order to circumvent these problems, the use of an alternative approach based on the use of pre-cut 17 × 19 mm filter paper pieces onto which larger amounts of sample (500 μL) can be retained by single deposition was proposed and evaluated. In this way, an approximately 12-fold increase in sensitivity and a more homogeneous distribution of the target analytes were obtained, permitting the development of a quantification strategy based on the use of matrix-matched urine samples of known analyte concentrations, which were subjected to the same procedure as the samples. Accuracy of this method, which provides LODs of 1.5 μg L- 1 for Mo and 6.5 μg L- 1 for Ti, was demonstrated after analysis of urine reference materials. Overall, the performance of the method developed is promising, being likely suitable for determination of other analytes in dried urine spots. © 2012 Elsevier B.V. All rights reserved. Source

Abian O.,Hospital Universitario Miguel Servet | Abian O.,Aragon Health science Institute ICS | Abian O.,University of Zaragoza | Abian O.,Research Center Biomedica En Red En El Area Tematica Of Enfermedades Hepaticas gestivas | And 12 more authors.
Molecular Pharmaceutics

Gaucher disease (GD) is a disorder of glycosphingolipid metabolism caused by deficiency of lysosomal glucocerebrosidase (GlcCerase) activity, due to conformationally or functionally defective variants, resulting in progressive deposition of glycosylceramide in macrophages. The glucose analogue, N-butyldeoxynojirimycin (NB-DNJ, miglustat), is an inhibitor of the ceramide-specific glycosyltransferase, which catalyzes the first step of glycosphingolipid biosynthesis and is currently approved for the oral treatment of type 1 GD. In a previous work, we found a GlcCerase activity increase in cell cultures in the presence of NB-DNJ, which could imply that this compound is not only a substrate reducer but also a pharmacological chaperone or inhibitor for GlcCerase degradation. In this work we compare imiglucerase (the enzyme currently used for replacement therapy) and velaglucerase alfa (a novel therapeutic enzyme form) in terms of conformational stability and enzymatic activity, as well as the effect of NB-DNJ on them. The interaction between these enzymes and NB-DNJ was studied by isothermal titration calorimetry. Our results reveal that, although velaglucerase alfa and imiglucerase exhibit very similar activity profiles, velaglucerase alfa shows higher in vitro thermal stability and is less prone to aggregation/precipitation, which could be advantageous for storage and clinical administration. In addition, we show that at neutral pH NB-DNJ binds to and enhances the stability of both enzymes, while at mildly acidic lysosomal conditions it does not bind to them. These results support the potential role of NB-DNJ as a pharmacological chaperone, susceptible of being part of pharmaceutical formulation or combination therapy for GD in the future. © 2011 American Chemical Society. Source

Resano M.,University of Zaragoza | Aramendia M.,Centro Universitario Of La Defensa | Rello L.,Miguel Servet Universitary Hospital | Calvo M.L.,Miguel Servet Universitary Hospital | And 2 more authors.
Journal of Analytical Atomic Spectrometry

This work investigates the potential of a 257 nm femtosecond (fs) laser ablation (LA) device operating at a high repetition rate (10 000 Hz) coupled to a multicollector (MC)-ICPMS to develop a method for the direct determination of Cu ratios in dried urine spots, prepared by deposition of urine (300 μL) onto precut clinical filter paper discs (16 mm diameter). The sampling capabilities offered by the fs LA system, permitting ablation of 150 μm thick coronas in the rim area of the filter, together with the use of admixed Ni as an internal standard, the proper optimization of the MC-ICPMS conditions (e.g., use of pseudo high-resolution mode to avoid interferences) and the use of a data processing approach particularly suitable for short transient signals (linear regression fit) enabled analysis of real urine samples with precision values around 500 ppm (RSD) for urinary Cu contents of a few hundred μg L -1. The methodology developed could prove to be useful for implementing screening protocols to detect Wilson's disease (WD), a well-known disorder related to Cu metabolism. In fact, the use of this analytical methodology permitted us to observe significant differences between (i) untreated WD patients and (ii) WD patients that are under treatment and control samples. This work represents the first time that determination of 65Cu/63Cu ratios has been used in the context of WD research, and serves as a proof of principle, suggesting that Cu isotope analysis could help in developing earlier and more reliable means to diagnose WD. This journal is © 2013 The Royal Society of Chemistry. Source

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