Nasal exudate for diagnosis of stroke: fundamental studies through iron fractionation, total iron, and targeted protein determinations.

During the last years, there has been an increasing research interest in the analysis of biological fluids requiring non-invasive sampling for biomedical and clinical applications. In this work, we have focused on the nasal exudate with the aim of investigating the potential use of this fluid to know the role of iron in stroke and also for diagnosis. Potential differences in the nasal exudate, collected in swabs, from diagnosed hemorrhagic stroke, ischemic stroke, and control groups were investigated with regard to total iron by inductively coupled plasma-mass spectrometry, iron fractionation studies by size exclusion chromatography together with post-column isotope dilution analysis, and four proteins containing iron (ferritin, transferrin, lactoferrin, and ferroportin) with ELISA kits. All these analyses represent an analytical challenge, considering the rather limited amount of sample (10-40 mg) available, being the nasal exudate extracted from the swab with 300 µL 10 mM Tris/HCl, pH = 7.4. Studies to obtain reliable analytical information, such as the blank contribution of the sampling step, evaluation of the extraction efficiency of the nasal exudate from the swab, and normalization strategies for data treatment, have been carried out. Results showed that despite the limited number of investigated samples, fractionation studies as well as the concentrations of ferritin and ferroportin obtained with ELISA kits showed a differential behavior between the different cohorts.

Targeted Analysis of Tears Revealed Specific Altered Metal Homeostasis in Age-Related Macular Degeneration.

Purpose: Specific altered metal homeostasis has been investigated in the tear film of age-related macular degeneration (AMD) patients considering that metal dyshomeostasis contributes to the production of free radicals, inflammation, and apoptosis and results in conformational changes of proteins. Methods: A multitargeted approach based on spectrophotometry and mass spectrometry techniques has been implemented to the multiplexed quantitation of lactoferrin (LF), S100 calcium binding protein A6 (S100A6), metallothionein 1A (MT1A), complement factor H (CFH), clusterin (CLU), amyloid precursor protein (APP), Mg, P, Na, Fe, Cu, Zn, and Ca, in the tear film from 60 subjects, 31 patients diagnosed with the dry form of AMD, and 29 healthy individuals. Results: Significant up-regulations of MT1A (1.9-fold) and S100A6 (1.4-fold) and down-regulations of LF (0.7-fold), Fe (0.6-fold), Mg (0.7-fold), and Cu (0.7-fold) were observed in AMD patients, when compared to control subjects. Of all the studied variables, only APP showed negative correlation with age in the AMD group. Also, positive correlations were observed for the variables Mg and Na, Cu and Mg, and P and Mg in both the AMD and control groups, whereas positive correlations were exclusively determined in the AMD group for Cu and LF, Na and Ca, and Mg and Ca. The panel constituted of MT1A, Na, and Mg predicts AMD disease in 73% of cases. Conclusions: The different levels of target metals and (metallo-)proteins in the tear film suggest altered metal homeostasis in AMD patients. These observed pathophysiological changes may be related with the anomalous protein aggregation in the macula.

Homeostatic alterations related to total antioxidant capacity, elemental concentrations and isotopic compositions in aqueous humor of glaucoma patients.

Glaucoma is a multifactorial eye disease, characterized by progressive optic neurodegeneration. Elevation of the intraocular pressure is the main risk factor for glaucoma and is a consequence of an imbalance in the aqueous humor hydrodynamics, the physiology of which is influenced by the homeostatic equilibrium of essential elements, oxidative stress, and antioxidants. The aim of this work was to study local alterations in glaucomatous patients from two different, but connected, points of view: (i) the total antioxidant capacity (as an indicator of oxidative damage) and (ii) the concentration of mineral elements and their isotopic composition. Such objective was pursued using aqueous humor from patients diagnosed with pseudoexfoliation glaucoma (PEXG, n = 17) and primary open-angle glaucoma (POAG, n = 5) and age-matched control subjects (n = 16). The total antioxidant capacity (TAC) was examined in both aqueous humor and 60 serum samples (n = 20 controls, n = 20 for PEXG, and n = 20 for POAG), both showing higher TAC for the glaucoma population. The concentrations of the essential mineral elements (Cu, Fe, Mg, Na, P, and Zn) and the isotopic compositions of Cu and Zn were determined in aqueous humor using single-collector and multi-collector inductively coupled plasma-mass spectrometry, respectively. Significant differences were established for Mg and P levels when comparing the results for glaucomatous patients with those for the control population (p < 0.01 and p < 0.05 for Mg and P respectively, ANOVA and Kruskal-Wallis). The Zn isotopic composition was significantly shifted from that for the control population for PEXG patients. A significant difference in the isotopic composition of Zn was also established between the PEXG and POAG glaucoma cohorts.

Pilot study of homeostatic alterations of mineral elements in serum of patients with age-related macular degeneration via elemental and isotopic analysis using ICP-mass spectrometry.

Age-related macular degeneration (AMD), the main cause of irreversible blindness in people over 60 years of age, is an eye disease that evolves with loss of central vision. Although AMD manifests itself in the eye, blood is continuously flowing through the macular region, such that potential alterations in this region could be reflected in the composition of whole blood or plasma/serum. Therefore, the potential clinical relevance of analysis of serum samples was assessed because of the low degree of invasiveness of blood sampling. 40 initial samples (20 from controls and 20 from patients with the dry form of AMD) have been analysed in this work to investigate the possible occurrence of homeostatic alterations of essential mineral elements caused by the disease. Both major (Na, Mg, P and K) and trace (Fe, Cu and Zn) essential mineral elements were determined in blood serum using single-collector ICP-mass spectrometry. Also, the isotopic composition of Cu (an element proposed to be directly involved in the onset of AMD) was determined using multi-collector ICP-mass spectrometry. Unexpected light Cu isotopic compositions in three individuals assumed as controls, resulted in a re-evaluation of their clinical information and a later exclusion due to pathologies initially not accounted for. In this pilot study, a significant alteration in the δ65Cu value has been found between the two final cohorts (AMD patients: n = 20; controls n = 17), with lower δ65Cu values (i.e. an enrichment in the light 63Cu isotope) in the case of AMD. Also, higher serum concentrations of the elements P and Zn were established in AMD at a systemic level.

Rapid evaluation of different perovskite absorber layers through the application of depth profile analysis using glow discharge - Time of flight mass spectrometry.

Depth profile analysis of perovskite absorber layers deposited onto glass substrates is investigated by radiofrequency pulsed glow discharge - time of flight mass spectrometry (rf-PGD-ToFMS). Elemental depth profiles obtained for perovskite films fabricated using a double-step deposition route with different precursors (methylammonium iodide and PbI2, PbCl2 or PbBr2) show varying distribution of the principle components depending on the precursors employed. Furthermore, the results show that rf-PGD-ToFMS allows to identify traces of residue solvent used in the initial film preparation (dimethyl sulphoxide or dimethylformamide) and to identify differences produced by film thickness and oxygen uptake caused by exposure to ambient conditions. The approach also enables inspection of the differences in elemental diffusion and the degradation processes. By using rf-PGD-ToFMS, no ultra-high-vacuum is needed for processing and rapid analysis of absorber films can be obtained in less than 40 s. The demonstration of such powerful analytical technique for obtaining depth profile information could enable groups in the field to better optimize processing conditions and enhance stability.

Characterization of thin film tandem solar cells by radiofrequency pulsed glow discharge - Time of flight mass spectrometry.

Beside low production costs and the use of nontoxic and abundant raw materials, silicon based thin-film solar cells have the advantage to be built up as multi junction devices like tandem or triple junction solar cells. Silicon thin film modules made of tandem cells with hydrogenated amorphous silicon (a-Si:H) top cell and microcrystalline (µc) Si:H bottom cell are available on the market. In this work, the analytical potential of state-of-the art radiofrequency (rf) pulsed glow discharge (PGD) time of flight mass spectrometry (TOFMS) commercial instrumentation is investigated for depth profiling analysis of tandem-junctions solar cells on 2mm thick glass substrate with 1µm thick ZnO:Al. Depth profile characterization of two thin film tandem photovoltaic devices was compared using millisecond and sub-millisecond rf-PGD regimes, as well as the so-called "low mass mode" available in the commercial instrument used. Two procedures for sample preparation, namely using flat or rough cell substrates, were compared and the distribution of dopant elements (phosphorous, boron and germanium) was investigated in both cases. Experimental results obtained by rf-PGD-TOFMS as well as electrical measurements of the samples showed that a worse depth resolution of dopant elements in the silicon layers (e.g. distribution of boron in a thicker region that suggests a diffusion of this dopant in the coating of the sample) found using a rough sample substrate was related to a higher power conversion efficiency.

Elemental and isotopic analysis of oral squamous cell carcinoma tissues using sector-field and multi-collector ICP-mass spectrometry.

Elemental and isotopic analysis via single-collector and multi-collector ICP-mass spectrometry, respectively, have been explored as a tool for identifying potential differences between non-tumor and oral squamous cell carcinoma tissues. Elemental concentrations of major and minor elements, known to be essential for different processes in the cell (i.e. Na, Ca, Mg, K, P, Fe, Cu and Zn), have been determined and results for cancerous and non-cancerous tissues collected from the same individual have been compared. Among the elements studied, only Mg, K and P turned out to be significantly higher in concentration in the tumor tissues. However, a shift towards higher and wider concentration ranges has also been observed for Cu and Zn in the tumor samples, whereas for Ca lower concentrations were established. Possible isotope ratio variations for Cu and Zn in both biological tissues have also been evaluated with the same goal. δ66Zn results did not provide an obvious trend, but in the case of Cu, a clear distinction between the tumor and non-tumor tissues was observed: δ65Cu values ranged between -0.68% and 0.03% in the non-tumor tissues, whereas tumor samples turned out to be enriched in 65Cu, with δ65Cu values between 0.10% and 0.93%. These results confirm the considerable potential of isotopic and elemental studies for biomedical purposes.

Tabaquismo y patología psiquiátrica asociada. Revisión de casos en un Centro de Tratamiento Ambulatorio de Adicciones / Smoking and associated psychiatric condition. Review of cases in an outpatient Addiction Treatment Center

En las últimas décadas, los estudios epidemiológicos han encontrado una clara asociación entre el consumo de nicotina y enfermedad mental. La presencia de comorbilidad psiquiátrica en los fumadores supone un dato de gran relevancia, tanto para su tratamiento como para el desarrollo de programas preventivos. A lo largo de los años, esta relevancia será mayor en tanto en cuanto vaya disminuyendo el número de fumadores en la población general. En el siguiente trabajo, se ha pretendido evaluar el porcentaje de pacientes con psicopatología asociada que acuden a un Centro de Tratamiento Ambulatorio de Adicciones con el objetivo de tratar su adicción a la nicotina (AU)

In recent decades, the epidemiological studies have found a clear association between nicotine consumption and mental disease. The presence of psychiatric comorbidity in smokers is very relevant for both its treatments as well as the development of preventive programs. Over the years, this relevance will become greater as the number of smokers decreases in the general population. This work has aimed to evaluate the percentage of patients with associated psychopathology who come to an Outpatient Addiction Treatment Center in order to treat their nicotine addiction (AU)

A novel approach to measure isotope ratios via multi-collector-inductively coupled plasma-mass spectrometry based on sample mixing with a non-enriched standard.

In this work, a novel approach to measure isotope ratios via multi-collector-inductively coupled plasma-mass spectrometry (MC-ICP-MS) for low amounts of target element is proposed. The methodology is based on mixing of the sample (target element isolate) with a non-enriched in-house standard, previously characterized for its isotopic composition. This methodology has been applied to isotopic analysis of Cu and of Fe in whole blood samples. For this purpose, different mixtures of sample + in-house standard were prepared and adjusted to a final concentration of 500 µg/L of the target elements for isotopic analysis. δ(65)Cu, δ(56)Fe, and δ(57)Fe varied linearly as a function of the amount of in-house standard (or of sample) present in the mixture. The isotopic composition of the sample was calculated considering the isotope ratios measured for (i) the mixture and (ii) the in-house standard and (iii) the relative concentrations of target element contributed by the sample and the standard to the mixture, respectively. For validation purposes, the isotopic analysis of whole blood Cu was carried out using both the conventional (using 2 mL of whole blood) and the newly developed approach (using 500 µL of whole blood). The δ(65)Cu values obtained using mixtures containing 40 % (200 µg/L) of Cu from the blood samples and 60 % (300 µg/L) of Cu from the in-house standard were in good agreement with the δ(65)Cu value obtained using the conventional approach (bias ≤0.15 ‰).

Pulsed radiofrequency glow discharge time-of-flight mass spectrometry for molecular depth profiling of polymer-based films.

We demonstrate the potential of an innovative technique, pulsed radiofrequency glow discharge time-of-flight mass spectrometry, for the molecular depth profiling of polymer materials. The technique benefits from the presence, in the afterglow of the pulsed glow discharge, of fragment ions that can be related to the structures of the polymers under study. Thin films of different polymers (PMMA, PET, PAMS, PS) were successfully profiled with retention of molecular information along the profile. Multilayered structures of the above polymers were also profiled, and it was possible to discriminate among layers having similar elemental composition but different polymer structure.

Nitrogen effects in multi-matrix calibrations by radiofrequency glow discharge--optical emission spectrometry.

A study about the effect of nitrogen in the calibration curves of a series of analytical emission lines has been carried out in this work. Fifteen reference materials with different matrices (Fe, Al, Zn, Cu and Ni) were used (three of these reference materials contain nitrogen in their composition) and plots of intensity versus the product "sputtering rate times element concentration" were constructed for emission lines of the analytes considered in this work (Al, Fe, Cu, Cr, C, Mo, Zn, Si, Ti and Ni). Two different fits were performed in each plot, first considering only the points corresponding to samples without nitrogen in their composition and secondly including all the points. The results show almost negligible differences in the emission yields calculated. On the other hand, a mixture of Ar containing 0.5% N2 was employed to check if the nitrogen effect was present at higher concentrations than those expected in analysis when samples with high nitrogen concentrations are used. Differences between the slopes of the calibration curves with the Ar/N2 and pure Ar discharges were obtained (up to 30%). A study of the molecular bands recorded in the spectra when nitrogen is present in the discharge and determination of the resulting interferences on the analytes have been performed.