Pets as Sentinels of Human Exposure to Neurotoxic Metals

The idea that animals may be used as sentinels of environmental hazards pending over humans and the associated public health implications is not a new one. Nowadays pets are being used as bioindicators for the effects of environmental contaminants in human populations. This is of paramount importance due to the large increase in the worldwide distribution of synthetic chemicals, particularly in the built environment. Companion animals share the habitat with humans being simultaneously exposed to and suffering the same disease spectrum as their masters. Moreover, their shorter latency periods (due to briefer lifespans) enable them to act as early warning systems, allowing timely public health interventions. The rise on ethical constraints on the use of animals and, consequently, on the sampling they can be subjected to has led to the preferential use of noninvasive matrices, and in this case we are looking into hair. This chapter focuses in three non-essential metals: mercury, lead, and cadmium, due to their ubiquitous presence in the built environment and their ability of affecting the mammal nervous system. There is a fairly short amount of studies reporting the concentrations of these metals in pets’ hair, particularly for cats. These studies are characterized, and the metal concentrations corresponding to different parameters (e.g., age, sex, diet, rearing) are described in order to provide the reader with a general vision on the use of this noninvasive matrix on the studies conducted since the last two decades of the twentieth century.publishe

Evaluation of metal distributions in small samples of mouse brain lesions (hematoma) by inductively coupled plasma mass spectrometry after sampling by laser microdissection (LMD)

Laser microdissection (LMD) used for sample preparation was combined off-line with inductively coupled plasma mass spectrometry (ICP-MS) to evaluate metal distributions in mouse brain with hematoma lesion. Small amounts (from 0.014 to 0.338 mg) of tissue were sampled from selected regions of the brain, with a hematoma lesion and also from regions without hematoma. The obtained samples were decomposed in closed vessel in a microwave oven and a micronebulizer in conjuction with a desolvation system was used for introducing the solution of the sample into the plasma. Accuracy was evaluated using certified reference materials (bovine liver and mussel tissue), whilst the agreement between the concentrations found with those certified was better than 85%. The limits of detection (LODs) of Cu, Fe and Zn for the small mouse brain tissue samples were 12.4, 12.5 and 9.6 mu g g(-1), respectively. The LODs of K and Na were 1.07 and 0.24 mg g(-1), respectively. The distribution of K. Na, Cu, Fe and Zn in the selected regions of the mouse brain was evaluated. It was observed that the Fe, Na and Zn concentrations were approximately 2-10 times higher in the hematoma region (inside and around the hematoma) than in the control (region without hematoma). The LMD system demonstrated to be useful for sampling small amounts of biological tissue from regions of interest for further analysis by ICP-MS. (C) 2011 Elsevier B.V. All rights reserved

Micronebulization for trace analysis of lanthanides in small biological specimens by ICP-MS

This work deals with the development of a mass spectrometric method for the determination of lanthanides (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) at ng g(-1) levels in small amounts of biological specimens by inductively coupled plasma-mass spectrometry (ICP-MS) after microwave digestion. Two different systems were investigated for introducing the aqueous solutions of the sample into the plasma: a desolvating system (APEX) with micronebulizer and a nano-volume flow injection system combined with a total consumption nebulizer (DS-5). Both solution introduction systems were used together with a quadrupole ICP mass spectrometer. The performances of the investigated nebulizers were compared to that of the MicroMist nebulizer, which was fitted to a mini cyclonic spray chamber. The solution uptake rate was: 700 mu L min(-1) for MicroMist, 330 mu L min(-1) for APEX and 8 mu L min(-1) for DS-5. By using the APEX and the DS-5 nebulizers the oxides formation rate is reduced compared to MicroMist nebulizer, but to a larger extent by APEX. The relative detection limits for lanthanides ranged from 0.57 to 6.1 ngL(-1) and 30 to 170 ng L-1 for the APEX and the DS-5 nebulizer, respectively. The absolute detection limits were in the range of 6.7 to 54 pg for APEX and 3.1 to 7.6 fg for DS-5. The method was applied for lanthanides determination in mussel tissue (BCR 668) and in slugs organs. Good precision and accuracy were obtained with the use of APEX, since the oxide interference is markedly reduced. Slight interference was still observed with the use the DS-5 nebulizer, mainly by Ba oxides. By using the nano-volume flow injection nebulizer, lanthanide determination in small amounts of slug tissue was possible, only requiring 76 nL of digested sample solution into the plasma of ICP-MS. (C) 2007 Elsevier B.V. All rights reserved

Detection of Zn-containing proteins in slug (Genus Arion) tissue using laser ablation ICP-MS after separation by gel electrophoresis

Assessing the inventory of biological systems in respect to metal species is a growing area of life science research called metallomics. Slugs are of special interest as monitor organisms for environmental contaminations. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was applied to map the distribution of total Zn in a section of a slug sample and to detect Zn-containing proteins after one-dimensional separation by gel electrophoresis (Blue Native PAGE). Interestingly, by far the largest fraction of protein bound Zn was explained by three sharp and prominent bands at 75,100 and 150 kDa. Analysis of tryptic digests of selected bands using MALDI-TOF-MS and public databases failed to identify proteins within the Zn bands what may be due to coverage gaps concerning the species anon ater. Three non-Zn containing bands could be assigned to proteins known from other mollusc species. (C) 2011 Elsevier B.V. All rights reserved

Monitoring of platinum in a single hair by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) after cisplatin treatment for cancer

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used to quantify and monitor the concentration of Pt along a single strand of hair from a patient who had been treated with cisplatin as cytostatic drug. The sensitivity of the analytical method developed could be increased by total ablation of the hair cross-section compared to partial ablation. A low-noise intensity ratio was obtained along the strand, while the blank was negligible. The variation of the Pt signal with reference to each cisplatin dose was clearly observed. Home-made standards consisting of Pt-enriched hair strands served as calibrators and sulphur (measuring S-34(+)) was used as the internal reference element. The correlation coefficient of the calibration curve for platinum was 0.9973 and the detection limit was 0.029 mu g g(-1). The rate of hair growth between doses was constant. The mean relative standard deviation (R.S.D.) for five replicates of single hair strands ranged from 15 to 22%. The maximum concentrations of Pt found along the hair strands were 26.9 +/- 5.3, 14.7 +/- 3.3, 20.9 +/- 3.9 and 26.1 +/- 3.8 mu g g(-1), which correspond to four treatment of cisplatin administered to the patient at 3-week intervals. (c) 2008 Elsevier B.V. All rights reserved

Bioimaging of metals in thin mouse brain section by laser ablation inductively coupled plamsa mass spectrometry: novel online quantification strategy using aqueous standards

A novel solution-based calibration method for quantitative spatial resolved distribution analysis (imaging) of elements in thin biological tissue sections by LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometry) is described. A dual flow of the carrier and nebulizer gas is used to transport the aerosol of the laser ablated solid sample (brain tissue) and that of the nebulized aqueous standard into inductively coupled plasma (ICP) source, respectively. Both aerosols are introduced separately in the injector tube inside a special ICP torch and then mixed in the inductively coupled plasma. Calibration curves were obtained via two different calibration strategies: (i) solution based calibration and (ii) with a set of well characterized homogeneous brain laboratory standards. In the first approach matrix matching is performed by solution nebulization of a series of aqueous standards with defined analyte concentrations and simultaneous laser ablation of brain homogenate followed by nebulization of 2% (v/v) HNO3 and laser ablation of a whole brain slice (line by line). In the second approach of calibration a set of brain homogenates with defined analyte concentrations is analyzed by LA-ICP-MS followed by the imaging of brain tissue under the same experimental conditions (dry plasma). Calibration curves of elements of interest (e. g., Li, Na, Al, K, Ca, Ti, V, Mn, Ni, Co, Cr, Cu, Zn, As, Se, Rb, Sr, Y, Cd, Ba, La, Ce, Nd, Gd, Hg, Pb, Bi and U) were obtained using (i) aqueous standards or (ii) the set of synthetic laboratory standards prepared from a mouse brain homogenate doped with elements at defined concentrations. The ratio of the slope of the calibration curves (obtained by using aqueous standards and solid standards) was applied to correct the differences of sensitivity among ICP-MS and LA-ICP-MS. Quantitative images of Li, Mn, Fe, Cu, Zn and Rb in mouse brain were obtained under wet plasma condition (nebulization of HNO3 solution in parallel with ablation of solid brain sample)

Methodologies for the Determination of Low Concentrations of Lathanides in Biological Samples by ICP-MS

This work deals with the development of analytical methods for lanthanide determination in biological samples. One method consists of using capillary electrophoresis (CE) for lanthanide separation prior to the detection by inductively coupled plasma mass spectrometry (ICP-MS). The lanthanides are extracted from the sample solution by liquid-liquid extraction with bis(2-ethylhexyl)orthophosphoric acid (HDEHP) in toluene at pH 2.0 and then backextracted into an aqueous phase using 6 mol L-1 HNO3. After solvent evaporation, the residue is dissolved with water, and 32 nL of this solution injected into the capillary. A mixture of 6 mmol L-1 8-hydroxyisobutyric acid (HIBA) with pH 4.2 is used as the electrolyte solution. It is demonstrated that the lanthanides are separated under this condition. The other method consists of using a micro nebulizer-desolvation system for introducing the sample into the plasma of an ICP-MS. The oxide formation rate is remarkably decreased by using this introduction system, allowing accurate lanthanide determination. The developed methods were applied to the determination of lanthanides at the ng g(-1) levels in mussel tissue. The concentrations of the elements were below the detection limits of the CE-ICP-MS method, but detected and quantified by using the micro nebulizer-desolvation system