Associations among exposure to methylmercury, reduced Reelin expression, and gender in the cerebellum of developing mice.

Genetic risk factors acting during pregnancy or early after birth have been proposed to account for the exponential increase of autism diagnoses in the past 20 years. In particular, a potential link with exposure to environmental mercury has been suggested. Male sex constitutes a second risk factor for autism. A third potential genetic risk factor is decreased Reelin expression. Male heterozygous reeler (rl(+/-)) mice show an autism-like phenotype, including Purkinje cells (PCs) loss and behavioral rigidity. We evaluated the complex interactions between 3 risk factors, i.e. genetic status, sex, and exposure to methylmercury (MeHg), in rl(+/-) mice. Mice were exposed to MeHg during the prenatal and early postnatal period, either at a subtoxic dose (2 ppm in Dams' drinking water), or at a toxic dose (6 ppm Dams' drinking water), based on observations in other rodent species and mice strains. We show that: (a) 2 ppm MeHg does not cause PCs loss in the different animal groups, and does not enhance PCs loss in rl(+/-) males; consistent with a lack of overt neurotoxicity, 2 ppm MeHg per se does not cause behavioral alterations (separation-induced ultrasonic calls in newborns, or sociability and social preference in adults); (b) in stark contrast, 6 ppm MeHg causes a dramatic reduction of PCs number in all groups, irrespective of genotype and sex. Cytochrome C release from mitochondria of PCs is enhanced in 6 ppm MeHg-exposed groups, with a concomitant increase of µ-calpain active subunit. At the behavioral level, 6 ppm MeHg exposure strongly increases ultrasonic vocalizations in all animal groups. Notably, 6 ppm MeHg significantly decreases sociability in rl(+/-) male mice, while the 2 ppm group does not show such as decrease. At a subtoxic dose, MeHg does not enhance the autism-like phenotype of male rl(+/-) mice. At the higher MeHg dose, the scenario is more complex, with some "autism-like" features (loss of sociability, preference for sameness) being evidently affected only in rl(+/-) males, while other neuropathological and behavioral parameters being altered in all groups, independently from genotype and sex. Mitochondrial abnormalities appear to play a crucial role in the observed effects.

Exosome release and low pH belong to a framework of resistance of human melanoma cells to cisplatin.

Intrinsic resistance to cytotoxic drugs has been a main issue in cancer therapy for decades. Microenvironmental acidity is a simple while highly efficient mechanism of chemoresistance, exploited through impairment of drug delivery. The latter is achieved by extracellular protonation and/or sequestration into acidic vesicles. This study investigates the importance of extracellular acidosis and nanovesicle (exosome) release in the resistance of human tumour cell to cisplatin (CisPt); in parallel to proton pump inhibitors (PPI) ability of interfering with these tumour cell features. The results showed that CisPt uptake by human tumour cells was markedly impaired by low pH conditions. Moreover, exosomes purified from supernatants of these cell cultures contained various amounts of CisPt, which correlated to the pH conditions of the culture medium. HPLC-Q-ICP-MS analysis revealed that exosome purified from tumour cell culture supernatants contained CisPt in its native form. PPI pre-treatment increased cellular uptake of CisPt, as compared to untreated cells, in an acidic-depend manner. Furthermore, it induced a clear inhibition of exosome release by tumour cells. Human tumours obtained from xenografts pretreated with PPI contained more CisPt as compared to tumours from xenografts treated with CisPt alone. Further analysis showed that in vivo PPI treatment induced a clear reduction in the plasmatic levels of tumour-derived exosomes which also contained lower level of CisPt. Altogether, these findings point to the identification of a double mechanism that human malignant melanoma use in resisting to a dreadful cellular poison such as cisplatin. This framework of resistance includes both low pH-dependent extracellular sequestration and an exosome-mediated elimination. Both mechanisms are markedly impaired by proton pump inhibition, leading to an increased CisPt-dependent cytotoxicity.

Human biomonitoring for Cd, Hg and Pb in blood of inhabitants of the Sacco Valley (Italy).

INTRODUCTION: The Sacco Valley (Lazio, Italy) is characterized by high density population and several industrial chemical productions that during the time had led to a substantial amount of by-products. The result was a severe environmental pollution of the area and in particular of the river Sacco. In 1991, the analysis of water and soils samples of three industrial landfills revealed the presence of organochlorine compounds and heavy metals. A research project named "Health of residents living in Sacco Valley area", coordinated by the regional Department of Epidemiology, was undertaken and financed to evaluate the state of health of the population living near those polluted areas. MATERIALS AND METHODS: Cd, Hg and Pb were quantified in 246 blood samples of potentially exposed residents of the Sacco Valley by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS). RESULTS: Individuals who agreed to be sampled did not exhibit high levels of the elements. The distance from the river does not seem to be directly connected with the elements levels in blood. The contribution of these contaminants to the total intake due to ingestion of food was difficult to evaluate. The unclear trend of data would require a characterization of the polluted site with environmental sampling of different matrices.

[Exploratory biomonitoring study among workers of livestock farms of the Taranto Province]. / Studio esplorativo di biomonitoraggio tra gli allevatori delle masserie della Provincia di Taranto.

OBJECTIVE: to conduct a survey on blood levels of metals and organochlorine compounds (dioxins and PCBs) among workers of livestock farms, and to identify the factors able to explain the magnitude and variability of the measured concentrations. DESIGN: exploratory human biomonitoring study. SETTING AND PARTICIPANTS: a sample of 45 workers from farms (masserie) located in the Province of Taranto was included in the study. The farms, located between 6 and 43 km from the industrial area, are family owned and animals (mainly sheep and goats) are locally reared outdoors. The study subjects have similar eating habits, including food consumption resulting from their production. RESULTS: manganese concentrations and, to a lesser extent, arsenic, cadmium and lead are in the medium-high range of levels observed in the Italian general population. This study does not identify factors able to explain the variability in the blood levels of metals. The amount of dioxins and PCBs, on the other hand, is strongly associated both with subjects age and the distance of farm from the industrial site. CONCLUSION: the results of this survey are suggestive of research hypotheses that need to be confirmed by biomonitoring studies of adequate design and size, in particular the hypothesis that the blood level of dioxins and PCBs decreases with increasing distance from the industrial site. We recommend ad hoc studies to better characterize the exposure of farmers (also associated with agricultural activities), and of the inhabitants of Taranto, to environmental persistent pollutants, also in terms of food matrices locally produced and consumed.

Dynamic reaction cell ICP-MS for determination of total As, Cr, Se and V in complex matrices: still a challenge? A review.

Mass interferences, caused by atomic or polyatomic species and having the same mass/charge ratio of the analyte, can be a severe limit for a reliable assay of trace and ultratrace elements by ICP-MS. The DRC™ technology uses a reaction gas to overcome these interferences. Reactions of charge exchange, atom transfer, adduct formation, condensation and analyte association/condensation are the main mechanisms. Interfering ions tend to react with the gas exothermally, while, the analyte reacts endothermally. Selecting the most appropriate reaction gas in DRC-ICP-MS is the very critical point for the determination of strongly interfered elements. A careful evaluation of the reaction mechanisms and the chemistry involved are required. The DRC allows the use of different gases, among them, ammonia (NH(3)), methane (CH(4)), hydrogen (H(2)) and oxygen (O(2)) are the most known, but there are other potentially useful gases like nitrous oxide (N(2)O), nitrogen oxide (NO), carbon dioxide (CO(2)), fluoromethane (CH(3)F), sulphur hexafluoride (SF(6)) and carbon disulfide (CS(2)). This paper provides a review on the analytical challenges for a reliable assay of As, Cr, Se and V by DRC-ICP-MS and illustrates different approaches and mechanisms involved in the analysis of polymers, biological fluids (serum, urine and whole blood), rock, soil and particulate matter.

Method validation for determination of cadmium and lead in offal by means of quadrupole inductively coupled plasma mass spectrometry.

Offal includes viscera and internal organs that have been removed from butchered animals, that may be either directly eaten or processed for the production of other foodstuff. Such organs are able to accumulate high concentrations of potentially toxic heavy metals posing a risk for human health when ingested. Because high levels of Cd and Pb may produce damages to humans, Commission Regulation no. 1881/2006 and its amendment established maximum levels for those two elements in edible bovine, porcine, and ovine offal. In the present study, a method based on microwave acid-assisted digestion and quadrupole inductively coupled plasma mass spectrometric quantification of Cd and Pb in offal was validated according to the EU common standards. The main parameters evaluated in the validation process were: the detection and the quantification limits (LoD, LoQ), the recovery, the repeatability, the within-laboratory reproducibility, the linearity range, and the standard measurement uncertainty. The results obtained for LoD and LoQ in microg kg(-1) were, respectively, Cd, 1.8 and 5.4; Pb, 5.1 and 15.5; meanwhile, the mean recovery was about 98% for Cd and 103% for Pb. Repeatability was around 5% for Cd and 4% for Pb. The expanded standard measurement uncertainty, expressed as percentage and with a coverage factor of 2, was estimated as follows: Cd, 4.9%; Pb, 8.7%. For both elements, the main contribution was due to the within-laboratory reproducibility of the measurements.

Calcium, copper, iron, magnesium, silicon and zinc content of hair in Parkinson's disease.

The aetiology of Parkinson's disease (PD) is still unknown, but some hypotheses have focused on the imbalances in body levels of metals as co-factors of risk. To assess whether hair could be a reliable marker of possible changes, calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), silicon (Si) and zinc (Zn) were determined in hair from 81 patients affected by PD and 17 age-matched controls. Care was taken to eliminate external contamination of the hair by thorough washing. Digestion of the matrix was achieved by an acid-assisted microwave procedure. Quantification of the elements was performed by inductively coupled plasma atomic emission spectrometry. Results indicated significantly lower levels of Fe in the hair of patients (p=0.018) compared with controls. Ca and Mg levels were slightly lower while Zn levels were higher in patients, although these differences were not significant; neither were variations in Cu and Si. Ca and Mg were at least 1.5 times higher in females than in males in both controls and patients. In addition, Ca correlated positively with Mg in both groups and in both sexes (p-value always less than 0.03), and negatively with age in patients (p<0.01). Finally, element levels did not correlate with either the duration or the severity of the disease or with anti-Parkinson treatment.

Development of methods for the quantification of essential and toxic elements in human biomonitoring.

Analytical methods using sector field ICP-MS and ICP-AES were developed for the determination of Al, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Ni, Pb, Sb, Si, Sn, Sr, Tl, V, W, Zn and Zr in cerebrospinal fluid, urine, serum and blood. Sample treatment procedures merging high sample throughput, simplicity and low contamination risk were set up. Method performances were evaluated in terms of detection limits, accuracy and precision. The limits were below 0.05 ng ml(-1) for all the elements, except for Al (all matrices), Hg (blood), Pb (blood) and Sn (serum and blood). The accuracy varied from 86% to 110% and the precision was always below 6%.

Metals and oxidative stress in patients with Parkinson's disease.

Twenty-six metals and the oxidative status in 71 patients affected by Parkinson's disease and 44 healthy individuals were compared in order to identify potential biomarkers of the disease. In the patients, the following significant imbalances were found (p < or = 0.05): i) in serum, an increment of Ca, Mg, Ni, Si and V, and a decrement of Cd, Co, Fe, Li, Sn, Zn and Zr; ii) in blood, raised levels of Co, Li, Ni and Si and decreased of Al, Be, Ca, Cd, Fe, Mg, Mo, Sn, Zn and Zr; iii) increased formation of oxidant species and lowered anti-oxidant capacity (p < or = 0.001 for both). Barium, Bi, Cr, Cu, Hg, Mn, Pb, Sb, Sr, Tl and W did not change with the disease. The best discriminating variables between patients and controls were Cd, Co, Fe, Ni and Si in serum (91.2% of cases correctly classified), and Al, Cd, Co, Fe, Mo and Si in blood (98.2% of cases properly classified).

Quantification of chemical elements in blood of patients affected by multiple sclerosis.

Although some studies suggested a link between exposure to trace elements and development of multiple sclerosis (MS), clear information on their role in the aetiology of MS is still lacking. In this study the concentrations of Al, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Ni, Pb, Sb, Si, Sn, Sr, Tl, V, W, Zn and Zr were determined in the blood of 60 patients with MS and 60 controls. Quantifications were performed by inductively coupled plasma (ICP) atomic emission spectrometry and sector field ICP mass spectrometry. When the two groups were compared, an increased level of Co, Cu and Ni and a decrement of Be, Fe, Hg, Mg, Mo, Pb and Zn in blood of patients were observed. In addition, the discriminant analysis pointed out that Cu, Be, Hg, Co and Mo were able to discriminate between MS patients and controls (92.5% of cases correctly classified).