The Association of Essential Metals with APOE Genotype in Alzheimer's Disease.

BACKGROUND: The major confirmed genetic risk factor for late-onset, sporadic Alzheimer's disease (AD) is variant ɛ4 of apolipoprotein E gene (APOE). It is proposed that ApoE, a protein involved in transport of cholesterol to neurons can cause neurodegeneration in AD through interaction with metals. Previous studies mostly associated copper, iron, zinc, and calcium with ApoE4-mediated toxicity. OBJECTIVE: To test the association of essential metals with APOE genotype. METHODS: We compared plasma and cerebrospinal fluid (CSF) levels of copper, zinc, iron, sodium, magnesium, calcium, cobalt, molybdenum, manganese, boron, and chromium, and CSF ferritin levels among AD, mild cognitive impairment (MCI) patients, and healthy controls (HC) with different APOE genotype. RESULTS: Sodium, copper, and magnesium levels were increased in carriers of ɛ4 allele. Additionally, the increase in sodium, calcium and cobalt plasma levels was observed in carriers of ɛ4/ɛx genotype. The decrease in boron plasma levels was observed in carriers of ɛ4 allele and ɛ4/ɛ4 genotype. Additionally, CSF zinc levels as well as plasma sodium levels were increased in AD patients compared to HC. CONCLUSION: These results indicate that the molecular underpinnings of association of essential metals and metalloids with APOE should be further tested and clarified in vivo and in vitro.

Effects of illumination on the categorization of shiny materials.

The present research was designed to examine how patterns of illumination influence the perceptual categorization of metal, shiny black, and shiny white materials. The stimuli depicted three possible objects that were illuminated by five possible high-dynamic-range imaging light maps, which varied in their overall distributions of illuminant directions and intensities. The surfaces included a low roughness chrome material, a shiny black material, and a shiny white material with both diffuse and specular components. Observers rated each stimulus by adjusting four sliders to indicate their confidence that the depicted material was metal, shiny black, shiny white, or something else, and these adjustments were constrained so that the sum of all four settings was always 100%. The results revealed that the metal and shiny black categories are easily confused. For example, metal materials with low intensity light maps or a narrow range of illuminant directions are often judged as shiny black, whereas shiny black materials with high intensity light maps or a wide range of illuminant directions are often judged as metal. To discover the visual information on which these judgements are based, we measured several possible image statistics, and we found two that were highly correlated with the observers' confidence ratings in appropriate contexts. We also performed a spherical harmonic analysis on the different light maps to quantitatively predict how they would bias observers' judgments of metal and shiny black surfaces.

Visualization and material-based differentiation of lodged projectiles by extended CT scale and the dual-energy index.

Computed tomography (CT) scans of gunshot wounds and their high sensitivity in detecting osseous lesions has often been reported in the literature. However, studies concerning in situ examinations of lodged projectiles with CT to determine the ammunition used are lacking. Projectile visualizations are hampered in standard CT due to the presence of metal artifacts and the limited range of Hounsfield units (HU). The use of special reconstruction algorithms can overcome these limitations. For instance, using extended CT scale (ECTS) reconstruction supports detailed visualizations of metallic objects. In addition to projectile visualizations, X-ray attenuation measurements (CT numbers) of metallic objects can be used to differentiate materials in CT. This study uses real forensic cases to demonstrate that-depending on the degree of deformation-a detailed visualization of lodged projectiles using ECTS can provide useful information regarding the ammunition used and allows accurate caliber measurements. Independent from the degree of deformation, the in situ classification of bullets, even fragmented bullets, according to their metallic components is feasible by dual-energy index (DEI) calculations. The assessment of a lodged projectile with CT images provides useful information on the case; thus, a close examination of lodged projectiles or bullet fragments should be a part of the overall radiological examination for cases of penetrating gunshot wounds.

Weight-of-Evidence Approach for Assessing Removal of Metals from the Water Column for Chronic Environmental Hazard Classification.

The United Nations and the European Union have developed guidelines for the assessment of long-term (chronic) chemical environmental hazards. This approach recognizes that these hazards are often related to spillage of chemicals into freshwater environments. The goal of the present study was to examine the concept of metal ion removal from the water column in the context of hazard assessment and classification. We propose a weight-of-evidence approach that assesses several aspects of metals including the intrinsic properties of metals, the rate at which metals bind to particles in the water column and settle, the transformation of metals to nonavailable and nontoxic forms, and the potential for remobilization of metals from sediment. We developed a test method to quantify metal removal in aqueous systems: the extended transformation/dissolution protocol (T/DP-E). The method is based on that of the Organisation for Economic Co-operation and Development (OECD). The key element of the protocol extension is the addition of substrate particles (as found in nature), allowing the removal processes to occur. The present study focused on extending this test to support the assessment of metal removal from aqueous systems, equivalent to the concept of "degradability" for organic chemicals. Although the technical aspects of our proposed method are different from the OECD method for organics, its use for hazard classification is equivalent. Models were developed providing mechanistic insight into processes occurring during the T/DP-E method. Some metals, such as copper, rapidly decreased (within 96 h) under the 70% threshold criterion, whereas others, such as strontium, did not. A variety of method variables were evaluated and optimized to allow for a reproducible, realistic hazard classification method that mimics reasonable worst-case scenarios. We propose that this method be standardized for OECD hazard classification via round robin (ring) testing to ascertain its intra- and interlaboratory variability. Environ Toxicol Chem 2019;38:1839-1849. © 2019 SETAC.

Prenatal Metal Concentrations and Childhood Cardiometabolic Risk Using Bayesian Kernel Machine Regression to Assess Mixture and Interaction Effects.

BACKGROUND: Trace metal concentrations may affect cardiometabolic risk, but the role of prenatal exposure is unclear. We examined (1) the relation between blood metal concentrations during pregnancy and child cardiometabolic risk factors; (2) overall effects of metals mixture (essential vs. nonessential); and (3) interactions between metals. METHODS: We measured 11 metals in maternal second-trimester whole blood in a prospective birth cohort in Mexico City. In children 4-6 years old, we measured body mass index (BMI), percent body fat, and blood pressure (N = 609); and plasma hemoglobin A1C (HbA1c), non-high-density lipoprotein (HDL) cholesterol, triglycerides, leptin, and adiponectin (N = 411). We constructed cardiometabolic component scores using age- and sex-adjusted z scores and averaged five scores to create a global risk score. We estimated linear associations of each metal with individual z scores and used Bayesian Kernel Machine Regression to assess metal mixtures and interactions. RESULTS: Higher total metals were associated with lower HbA1c, leptin, and systolic blood pressure, and with higher adiponectin and non-HDL cholesterol. We observed no interactions between metals. Higher selenium was associated with lower triglycerides in linear (ß = -1.01 z score units per 1 unit ln(Se), 95% CI = -1.84, -0.18) and Bayesian Kernel Machine Regression models. Manganese was associated with decreased HbA1c in linear models (ß = -0.32 and 95% CI = -0.61, -0.03). Antimony and arsenic were associated with lower leptin in Bayesian Kernel Machine Regression models. Essential metals were more strongly associated with cardiometabolic risk than were nonessential metals. CONCLUSIONS: Low essential metals during pregnancy were associated with increased cardiometabolic risk factors in childhood.

Tracking atmospheric dispersion of metals in Rio de Janeiro Metropolitan region (Brazil) with epiphytes as bioindicators.

The atmospheric dispersion atmospheric plume of the metropolitan region and neighborhoods of the city of Rio de Janeiro was investigated through elemental analyzes (Na, K, Al, Mn, Pb, Ni, Cr) and stable lead isotopes in two epiphytes; the lichen Parmotrema crinitum (Ach.) and the bromeliad Tillandsia usneoides (L.). All the elements had lower concentrations in epiphytes than in rocks of the local geological basement, with the exception of K, which was similar to rocks. This behavior was attributed to the nutritional essentiality and abundance of this element in the environment. The concentrations of Na, Pb and the 206Pb/207Pb and 208Pb/206Pb ratios indicated the presence of spatial gradients in the path (a) sea shore → continent, and (b) urban center → farmlands. These patterns were associated with the mesoscale atmospheric circulation regime, in which, during the arrival of cold fronts, air masses from the metropolitan region of Rio de Janeiro are transported towards the mountainous region of Teresópolis, which acts as a barrier to the dispersion of pollutants. The bromeliad Tillandsia usneoides and the lichen Parmotrema crinitum were linked to Na and Pb atmospheric levels, respectively.

Effect doses for protection of human health predicted from physicochemical properties of metals/metalloids.

Effect doses (EDs) of metals/metalloids, usually obtained from toxicological experiments are required for developing environmental quality criteria/standards for use in assessment of hazard or risks. However, because in vivo tests are time-consuming, costly and sometimes impossible to conduct, among more than 60 metals/metalloids, there are sufficient data for development of EDs for only approximately 25 metals/metalloids. Hence, it was deemed a challenge to derive EDs for additional metals by use of alternative methods. This study found significant relationships between EDs and physicochemical parameters for twenty-five metals/metalloids. Elements were divided into three classes and then three individual empirical models were developed based on the most relevant parameters for each class. These parameters included log-ßn, ΔE0 and Xm2r, respectively (R2 = 0.988, 0.839, 0.871, P < 0.01). Those models can satisfactorily predict EDs for another 25 metals/metalloids. Here, these alternative models for deriving thresholds of toxicity that could be used to perform preliminarily, screen-level health assessments for metals are presented.

Assessing bioavailability levels of metals in effluent-affected rivers: effect of Fe(III) and chelating agents on the distribution of metal speciation.

To assess the effects of Fe(III) and anthropogenic ligands on the bioavailability of Ni, Cu, Zn, and Pb, concentrations of bioavailable metals were measured by the DGT (diffusive gradients in thin films) method in some urban rivers, and were compared with concentrations calculated by a chemical equilibrium model (WHAM 7.0). Assuming that dissolved Fe(III) (<0.45 µm membrane filtered) was in equilibrium with colloidal iron oxide, the WHAM 7.0 model estimated that bioavailable concentrations of Ni, Cu, and Zn were slightly higher than the corresponding values estimated assuming that dissolved Fe(III) was absent. In contrast, lower levels of free Pb were predicted by the WHAM 7.0 model when dissolved Fe(III) was included. Estimates showed that most of the dissolved Pb was present as colloidal iron-Pb complex. Ethylene-diamine-tetra-acetic acid (EDTA) concentrations at sampling sites were predicted from the relationship between EDTA and the calculated bioavailable concentration of Zn. When both colloidal iron and predicted EDTA concentrations were included in the WHAM 7.0 calculations, dissolved metals showed a strong tendency to form EDTA complexes, in the order Ni > Cu > Zn > Pb. With the inclusion of EDTA, bioavailable concentrations of Ni, Cu, and Zn predicted by WHAM 7.0 were different from those predicted considering only humic substances and colloidal iron.

Effect of Ocean Acidification on Organic and Inorganic Speciation of Trace Metals.

Rising concentrations of atmospheric carbon dioxide are causing acidification of the oceans. This results in changes to the concentrations of key chemical species such as hydroxide, carbonate and bicarbonate ions. These changes will affect the distribution of different forms of trace metals. Using IPCC data for pCO2 and pH under four future emissions scenarios (to the year 2100) we use a chemical speciation model to predict changes in the distribution of organic and inorganic forms of trace metals. Under a scenario where emissions peak after the year 2100, predicted free ion Al, Fe, Cu, and Pb concentrations increase by factors of up to approximately 21, 2.4, 1.5, and 2.0 respectively. Concentrations of organically complexed metal typically have a lower sensitivity to ocean acidification induced changes. Concentrations of organically complexed Mn, Cu, Zn, and Cd fall by up to 10%, while those of organically complexed Fe, Co, and Ni rise by up to 14%. Although modest, these changes may have significance for the biological availability of metals given the close adaptation of marine microorganisms to their environment.

The influence of metal speciation in combustion waste on the efficiency of Cu, Pb, Zn, Cd, Ni and Cr bioleaching in a mixed culture of sulfur-oxidizing and biosurfactant-producing bacteria.

Metal leachability from ash and combustion slag is related to the physico-chemical properties, including their speciation in the waste. Metals speciation is an important factor that influences the efficiency of metal bioleaching from combustion wastes in a mixed culture of acidophilic and biosurfactant-producing bacteria. It was observed that individual metals tended to occur in different fractions, which reflects their susceptibility to bioleaching. Cr and Ni were readily removed from wastes when present with a high fraction bound to carbonates. Cd and Pb where not effectively bioleached when present in high amounts in a fraction bound to organic matter. The best bioleaching results were obtained for power plant slag, which had a high metal content in the exchangeable, bound to carbonates and bound to Fe and Mg oxides fractions- the metal recovery percentage for Zn, Cu and Ni from this waste exceeded 90%.

Size characterization of dissolved metals and organic matter in source waters to streams in developed landscapes.

Individual and mixed water samples from wastewater treatment plant effluents, stormwater runoff, streams from developed areas were characterized with respect to organic matter concentration and spectral properties and metal concentration and size distribution. In addition, asymmetric flow-field flow fractionation coupled to inductively coupled plasma mass spectrometry was used to measure concentration, size distribution and association of metals in the colloidal size range. Results reveal that Fe, Cu, Zn and Pb in the colloidal size range were mainly associated with the less than 5 nm, or less than 10 kDa size range. Cu was most strongly associated with organic matter, while Zn and Pb were mixed between Fe and organic matter. Effluent showed higher binding capacity for metals, while stormwater, even with higher organic matter concentrations showed more exchangeable metals. Upon mixing of source waters, colloidal metal concentrations and size distributions were conserved.

Chemical species of metallic elements in the aquatic environment of an ex-mining catchment.

This study was conducted to investigate the chemical speciation of dissolved and particulate elements (lead, zinc, copper, chromium, arsenic, and tin) in the mining wastewater of a former tin-mining catchment. The speciation patterns of dissolved elements were estimated by an adsorptive stripping voltammeter (ASV), while particulate elements were analyzed by using a newly developed sequential-extraction leaching procedure. The procedure has been operationally defined among five host fractions, namely exchangeable, carbonate, reducible, organic bound, and residual fractions. A total of six elements (lead, zinc, copper, chromium, arsenic, and tin) were analyzed in thirty samples at ten locations (P1-P10), with three samples taken from each of the ten locations, to get the average value from the former tin-mining catchment. The results showed that the heavy metal pollutions in locations P4 and P8 were more severe than in other sampling sites, especially tin and lead pollution. In the water samples from locations P4 and P8, both the total contents and the most dangerous non-residual fractions of tin and lead were extremely high. More than 90% of the total concentrations of arsenic and chromium existed in the residual fraction. Concentrations of copper and zinc mainly occurred in the residual fraction (more than 60%), while lead and tin presented mostly in the non-residual fractions in surface water. For all of the six dissolved elements, the less-labile species formed the predominant fraction in their speciation patterns. The speciation patterns of particulate elements showed that most of the concentrations of zinc, copper, chromium, and arsenic were found in the reducible fraction; whereas lead and tin were mainly associated with the organic fraction.

Using risk-ranking of metals to identify which poses the greatest threat to freshwater organisms in the UK.

Freshwater aquatic organisms face the challenge of being exposed to a multitude of chemicals discharged by the human population. The objective of this study was to rank metals according to the threat they pose to aquatic organisms. This will contribute to a wider Chemical Strategy for freshwater which will risk-rank all chemicals based on their potential risk to wildlife in a UK setting. The method involved comparing information on ecotoxicological thresholds with measured concentrations in rivers. The bioconcentration factor was also considered as a ranking method. The metals; Ag, Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn, were analysed using this approach. Triclosan and lindane were used as comparative organic pollutants. Using a range of ranking techniques, Cu, Al and Zn came top of the list of concern, with Cu coming first.

Plant chitinase responses to different metal-type stresses reveal specificity.

KEY MESSAGE: Chitinases in Glycine max roots specifically respond to different metal types and reveal a polymorphism that coincides with sensitivity to metal toxicity. Plants evolved various defense mechanisms to cope with metal toxicity. Chitinases (EC 3.2.1.14), belonging to so-called pathogenesis-related proteins, act as possible second line defense compounds in plants exposed to metals. In this work their activity was studied and compared in two selected soybean (Glycine max L.) cultivars, the metal-tolerant cv. Chernyatka and the sensitive cv. Kyivska 98. Roots were exposed to different metal(loid)s such as cadmium, arsenic and aluminum that are expected to cause toxicity in different ways. For comparison, a non-metal, NaCl, was applied as well. The results showed that the sensitivity of roots to different stressors coincides with the responsiveness of chitinases in total protein extracts. Moreover, detailed analyses of acidic and neutral proteins identified one polymorphic chitinase isoform that distinguishes between the two cultivars studied. This isoform was stress responsive and thus could reflect the evolutionary adaptation of soybean to environmental cues. Activities of the individual chitinases were dependent on metal type as well as the cultivar pointing to their more complex role in plant defense during this type of stress.

Metals as a common trigger of inflammation resulting in non-specific symptoms: diagnosis and treatment.

BACKGROUND: The multiple symptoms of chronic fatigue syndrome (CFS) and fibromyalgia resemble those described in patients suffering from autoimmune/inflammatory syndrome induced by adjuvants (ASIA). It has been suggested that chronic metal-induced inflammation might play a role both in CFS and fibromyalgia as well as in ASIA. Humans are exposed to metals mainly through the release of metal ions from corroding dental restorations and orthopedic implants, food, vaccines and jewelry. Metals readily bind to sulphur and other groups in the mitochondria, enzymes and cell proteins. Metal-bound proteins are recognized by the immune system of susceptible subjects and might trigger an abnormal immune response, including allergy and autoimmunity. OBJECTIVES: To study three subjects with CFS and two with fibromyalgia, all of whom suspected metal exposure as a trigger for their ill health. METHODS: We measured delayed-type hypersensitivity to metals (metal allergy) using a validated lymphocyte transformation test, LTT-MELISA. All patients except one were sensitized to metals present in their dental restorations. The remaining patient reacted to metals in his skull implant. The removal of sensitizing metals resulted in long-term health improvement. Nine healthy controls matched for gender and age showed only marginal reactivity to the metals tested. CONCLUSIONS: Patients with CFS and fibromyalgia are frequently sensitized to metals found in the environment or used in dentistry and surgery. This allergy to metals might initiate or aggravate non-specific symptoms in metal-sensitized patients.

Critical materials and dissipative losses: a screening study.

This study deals with dissipative losses of critical materials between the life-cycle stages of manufacturing and end-of-life. Following the EU definition for critical materials, a screening of dissipative losses for the respective materials has been performed based on existing data and the most significant data gaps have been identified. Furthermore, a classification scheme for dissipative losses (dissipation into environment, dissipation into other material flows, dissipation to landfills) and for assessing their degree has been developed and a first qualitative assessment applying this classification scheme has been performed. In combination with existing criticality assessments, the results can be used to generate a map of metals indicating future research needs for analyzing metal dissipation in detail. The results include quantitative estimates of dissipative losses (where feasible) along the chosen life-cycle stages, and discuss research needs for analysis and avoidance of dissipative losses for improved resource efficiency.

[Concomitant influence of occupational and social risk factors on health of workers engaged into powder metallurgy].

Results of health risk evaluation in workers engaged into powder metallurgy, using complex of hygienic, medical, epidemiologic and sociologic studies, enable to define priority occupational and social risk factors, to assess degree of their influence on the workers' health and to identify occupationally induced diseases.

Metal speciation and toxicity of Tamar Estuary water to larvae of the Pacific oyster, Crassostrea gigas.

As part of the PREDICT Tamar Workshop, the toxicity of estuarine waters in the Tamar Estuary (southwest England) was assessed by integration of metal speciation determination with bioassays. High temporal resolution metal speciation analysis was undertaken in situ by deployment of a Voltammetric In situ Profiling (VIP) system. The VIP detects Cd (cadmium), Pb (lead) and Cu (copper) species smaller than 4 nm in size and this fraction is termed 'dynamic' and considered biologically available. Cadmium was mainly present in the dynamic form and constituted between 56% and 100% of the total dissolved concentration, which was determined subsequently in the laboratory in filtered discrete samples. In contrast, the dynamic Pb and Cu fractions were less important, with a much larger proportion of these metals associated with organic ligands and/or colloids (45-90% Pb and 46-85% Cu), which probably reduced the toxicological impact of these elements in this system. Static toxicity tests, based on the response of Crassostrea gigas larva exposed to discrete water samples showed a high level of toxicity (up to 100% abnormal development) at two stations in the Tamar, particularly during periods of the tidal cycle when the influence of more pristine coastal water was at its lowest. Competitive ligand-exchange Cu titrations showed that natural organic ligands reduced the free cupric ion concentration to levels that were unlikely to have been the sole cause of the observed toxicity. Nonetheless, it is probable that the combined effect of the metals determined in this work contributed significantly to the bioassay response.