We explored acquired immunity resulting from vaccination in 3 to 7-year-old children, chronically exposed to multiple heavy metals and metalloids, in an e-waste recycling area (Guiyu, China). Child ...blood levels of ten heavy metals and metalloids, including lead (Pb), arsenic (As), mercury (Hg), chromium (Cr), cadmium (Cd), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn) and selenium (Se), and seven vaccine antibodies (diphtheria, pertussis, tetanus, hepatitis B, Japanese encephalitis, polio, measles) were measured. The exposed group had higher levels of blood Pb, Mn, Cu, Zn and Cr compared to the reference group (P < 0.05). Levels of all vaccine antibodies in the exposed group were significantly lower than in the reference group (P < 0.01). All vaccine antibodies negatively correlated with blood concentrations of Cu, Zn and Pb, based on spearman rank correlation analysis. Multiple logistic regression and univariate analyses identified the location of residence (Guiyu), high blood Pb (>10 μg/dL) and high blood Cu and Zn (upper median value of each group) to be inversely associated with seven antibody titers. Antibody titers increased with age, BMI, high blood Mn (>15 μg/L), and high blood Cd and Ni (upper median value of each group). Results suggest multiple heavy metal and metalloid exposure, especially to Pb, Zn and Cu, may be a risk factor inhibiting the development of child immunity, resulting in decreased child antibody levels against vaccines.
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•We examined the associations of multiple heavy metals and metalloids with seven vaccine antibodies.•Higher levels of blood Pb, Mn, Cu, Zn and Cr were found in children from the e-waste- polluted area.•All vaccine antibodies Levels except hepatitis B were significantly reduced in the exposed area.•High blood Pb, Cu and Zn were observed to be inversely associated with seven antibody titers.•Multiple heavy metal and metalloid exposure may inhibit child antibody levels against vaccines.
Multiple heavy metals and metalloid exposure may be one of the risk factors inhibiting the development of child immunity, resulting in decreased child antibody levels against vaccines in e-waste-exposed children.
The development of a risk management system for nanoscale or ultrafine particle-types requires a base set of hazard data. Assessing risk is a function of hazard and exposure data. Previously, we have ...suggested "parallel tracks" as a strategy for conducting nanoparticle research. On the one hand, mechanistic studies on "representative" nanoparticles could be supported by governmental agencies. Alternatively, with regard to commercial nanoparticles, the environmental, health and safety (EHS) framework would include a minimum base set of toxicity studies which should be supported by the companies that are developing nano-based products. The minimum base set could include the following criteria: substantial particle characterization, pulmonary toxicity studies, acute dermal toxicity and sensitization studies, acute oral and ocular toxicity studies, along with screening type genotoxicity, and aquatic toxicity studies. We report here the toxicity results of a base set of hazard tests on a set of newly developed, well-characterized, ultrafine TiO(2) (uf-TiO(2)) particle-types. In vivo pulmonary toxicity studies in rats demonstrated low inflammatory potential and lung tissue toxicity. Acute dermal irritation studies in rabbits and local lymph node assay results in mice indicated that uf-TiO(2) was not a skin irritant or dermal sensitizer. Acute oral toxicity studies demonstrated very low toxicity and uf-TiO(2) produced short-term and reversible ocular conjunctival redness in rabbits. Genotoxicity tests demonstrated that uf-TiO(2) was negative in both the bacterial reverse mutation test and in an in vitro mammalian chromosome aberration test with Chinese hamster ovary cells. The results of aquatic toxicity screening studies demonstrated that uf-TiO(2) exhibited low concern for aquatic hazard in unaerated, 48h, static acute tests using the water flea, Daphnia magna; exhibited low concern for aquatic hazard in unaerated, 96h, static acute tests using the rainbow trout, Oncorhynchus mykiss; and exhibited medium concern in a 72h acute test using the green algae Pseudokirchneriella subcapitata. To summarize the findings, the results of most of the studies demonstrated low hazard potential in mammals or aquatic species following acute exposures to the ultrafine TiO(2) particle-types tested in this program.
Injectable hydrogels have received much attention because of the advantages of simulation of the natural extracellular matrix, microinvasive implantation, and filling and repairing of complex shape ...defects. Yet, for bone repair, the current injectable hydrogels have shown significant limitations such as the lack of tissue adhesion, deficiency of self-healing ability, and absence of osteogenic activity. Herein, a strategy to construct mussel-inspired bisphosphonated injectable nanocomposite hydrogels with adhesive, self-healing, and osteogenic properties is developed. The nano-hydroxyapatite/poly(l-glutamic acid)-dextran (nHA/PLGA-Dex) dually cross-linked (DC) injectable hydrogels are fabricated via Schiff base cross-linking and noncovalent nHA-BP chelation. The chelation between bisphosphonate ligands (alendronate sodium, BP) and nHA favors the uniform dispersion of the latter. Moreover, multiple adhesion ligands based on catechol motifs, BP, and aldehyde groups endow the hydrogels with good tissue adhesion. The hydrogels possess excellent biocompatibility and the introduction of BP and nHA both can effectively promote viability, proliferation, migration, and osteogenesis differentiation of MC3T3-E1 cells. The incorporation of BP groups and HA nanoparticles could also facilitate the angiogenic property of endothelial cells. The nHA/PLGA-Dex DC hydrogels exhibited considerable biocompatibility despite the presence of a certain degree of inflammatory response in the early stage. The successful healing of a rat cranial defect further proves the bone regeneration ability of nHA/PLGA-Dex DC injectable hydrogels. The developed tissue adhesive osteogenic injectable nHA/PLGA-Dex hydrogels show significant potential for bone regeneration application.
•Toxicity of common oxidants and their quenching agents was investigated.•Manganese dioxide is recommended for hydrogen peroxide quenching (P. subcapitata).•Sodium sulfite is not a suitable quenching ...agent for V. fischeri bioassays.•Persulfate and peroxymonosulfate exhibit high D. magna toxicity.•Catalase exhibits high P. subcapitata toxicity.
The inhibitory effect of commonly known oxidants and their quenching agents was investigated by employing a battery of toxicity tests. Hydrogen peroxide toxicity could be effectively eliminated by the enzyme catalase, whereas sodium thiosulfate and ascorbic acid were recommended as suitable quenching agents for the removal of the oxidants persulfate and peroxymonosulfate in the Vibrio fischeri bioassays. None of the studied quenching agents was found to be suitable for persulfate and peroxymonosulfate in the Daphnia magna bioassays since high inhibitory effects were obtained for both oxidants. In the case of Pseudokirchneriella subcapitata, manganese dioxide powder should be used as an alternative quenching agent to catalase, since this enzyme exhibited a highly toxic effect towards these microalgae. Sodium sulfite, which is extensively used as a quenching agent, was not appropriate for quenching peroxymonosulfate in all studied bioassays.
A worldwide survey of neonicotinoids in honey Mitchell, E. A. D.; Mulhauser, B.; Mulot, M. ...
Science (American Association for the Advancement of Science),
10/2017, Letnik:
358, Številka:
6359
Journal Article
Recenzirano
Odprti dostop
Growing evidence for global pollinator decline is causing concern for biodiversity conservation and ecosystem services maintenance. Neonicotinoid pesticides have been identified or suspected as a key ...factor responsible for this decline. We assessed the global exposure of pollinators to neonicotinoids by analyzing 198 honey samples from across the world. We found at least one of five tested compounds (acetamiprid, clothianidin, imidacloprid, thiacloprid, and thiamethoxam) in 75% of all samples, 45% of samples contained two or more of these compounds, and 10% contained four or five. Our results confirm the exposure of bees to neonicotinoids in their food throughout the world. The coexistence of neonicotinoids and other pesticides may increase harm to pollinators. However, the concentrations detected are below the maximum residue level authorized for human consumption (average ± standard error for positive samples: 1.8 ± 0.56 nanograms per gram).
Pesticides are usually present as mixtures in water environments. Evaluating the toxic effects of individual pesticide may not be enough for protecting ecological environment due to interactions ...among substances. In this study, we aimed to examine the lethal doses and gene expression changes in zebrafish (Danio rerio) upon exposure to individual and mixture pesticides malathion (MAL), chlorpyrifos (CHL) and lambda-cyhalothrin (LCY). Individual pesticide toxicity evaluation manifested that the toxicity of the three pesticides to D. rerio at various developmental stages (embryonic, larval, juvenile and adult stages) followed the order of LCY > CHL > MAL. On the contrary, the least toxicity to the animals was discovered from MAL. Most of the tested pesticides displayed lower toxicities to the embryonic stage compared with other life stages of zebrafish. Synergistic effects were monitored from two binary mixtures of LCY in combination with MAL or CHL and ternary mixture of MAL + CHL + LCY. The expressions of 16 genes involved in oxidative stress, immunity system, cell apoptosis and endocrine disruption at the mRNA level revealed that embryonic zebrafish were influenced by the individual or mixture pesticides. The expressions of Tnf, P53, TRα, Crh and Cyp19a exerted greater variations upon exposure to pesticide mixtures compared with their individual compounds. Collectively, the transcriptional responses of these genes might afford early warning biomarkers for identifying pollutant exposure, and the data acquired from this study provided valuable insights into the comprehensive toxicity of pesticide mixtures to zebrafish.
•Lambda-cyhalothrin was the most toxic to zebrafish among three tested pesticides.•Lambda-cyhalothrin in combination with malathion or chlorpyrifos exerted synergism.•Expressions of 5 genes exerted greater changes in mixtures compared to individuals.•Evaluation of single-compound data may underrate the risk of pesticide mixtures.
Abstract Zebrafish embryos have been shown to be a useful model for the detection of direct acting teratogens. This communication presents a protocol for a 3-day in vitro zebrafish embryo ...teratogenicity assay and describes results obtained for 10 proteratogens: 2-acetylaminofluorene, benzoapyrene, aflatoxin B1 , carbamazepine, phenytoin, trimethadione, cyclophosphamide, ifosfamide, tegafur and thio-TEPA. The selection of the test substances accounts for differences in structure, origin, metabolism and water solubility. Apart from 2-acetylaminofluorene, which mainly produces lethal effects, all proteratogens tested were teratogenic in zebrafish embryos exposed for 3 days. The test substances and/or the substance class produced characteristic patterns of fingerprint endpoints. Several substances produced effects that could be identified already at 1 dpf (days post fertilization), whereas the effects of others could only be identified unambiguously after hatching at ≥3 dpf. The LC50 and EC50 values were used to calculate the teratogenicity index (TI) for the different substances, and the EC20 values were related to human plasma concentrations. Results lead to the conclusion that zebrafish embryos are able to activate proteratogenic substances without addition of an exogenous metabolic activation system. Moreover, the teratogenic effects were observed at concentrations relevant to human exposure data. Along with other findings, our results indicate that zebrafish embryos are a useful alternative method for traditional teratogenicity testing with mammalian species.
The knowledge on potential harmful effects of metallic nanomaterials lags behind their increased use in consumer products and therefore, the safety data on various nanomaterials applicable for risk ...assessment are urgently needed. In this study, 11 metal oxide nanoparticles (MeOx NPs) prepared using flame pyrolysis method were analyzed for their toxicity against human alveolar epithelial cells A549, human epithelial colorectal cells Caco2 and murine fibroblast cell line Balb/c 3T3. The cell lines were exposed for 24 h to suspensions of 3-100 μg/mL MeOx NPs and cellular viability was evaluated using. Neutral Red Uptake (NRU) assay. In parallel to NPs, toxicity of soluble salts of respective metals was analyzed, to reveal the possible cellular effects of metal ions shedding from the NPs. The potency of MeOx to produce reactive oxygen species was evaluated in the cell-free assay. The used three cell lines showed comparable toxicity responses to NPs and their metal ion counterparts in the current test setting. Six MeOx NPs (Al2O3, Fe3O4, MgO, SiO2, TiO2, WO3) did not show toxic effects below 100 µg/mL. For five MeOx NPs, the averaged 24 h IC50 values for the three mammalian cell lines were 16.4 µg/mL for CuO, 22.4 µg/mL for ZnO, 57.3 µg/mL for Sb2O3, 132.3 µg/mL for Mn3O4 and 129 µg/mL for Co3O4. Comparison of the dissolution level of MeOx and the toxicity of soluble salts allowed to conclude that the toxicity of CuO, ZnO and Sb2O3 NPs was driven by release of metal ions. The toxic effects of Mn3O4 and Co3O4 could be attributed to the ROS-inducing ability of these NPs. All the NPs were internalized by the cells according to light microscopy studies but also proven by TEM, and internalization of Co3O4 NPs seemed to be most prominent in this aspect. In conclusion, this work provides valuable toxicological data for a library of 11 MeOx NPs. Combining the knowledge on toxic or non-toxic nature of nanomaterials may be used for safe-by-design approach.
Ureases are metalloenzymes that hydrolyze urea into ammonia and carbon dioxide. They were the first enzymes to be crystallized and, with them, the notion that enzymes are proteins became accepted. ...Novel toxic properties of ureases that are independent of their enzyme activity have been discovered in the last three decades. Since our first description of the neurotoxic properties of canatoxin, an isoform of the jack bean urease, which appeared in Toxicon in 1981, about one hundred articles have been published on “new” properties of plant and microbial ureases. Here we review the present knowledge on the non-enzymatic properties of ureases. Plant ureases and microbial ureases are fungitoxic to filamentous fungi and yeasts by a mechanism involving fungal membrane permeabilization. Plant and at least some bacterial ureases have potent insecticidal effects. This entomotoxicity relies partly on an internal peptide released upon proteolysis of ingested urease by insect digestive enzymes. The intact protein and its derived peptide(s) are neurotoxic to insects and affect a number of other physiological functions, such as diuresis, muscle contraction and immunity. In mammal models some ureases are acutely neurotoxic upon injection, at least partially by enzyme-independent effects. For a long time bacterial ureases have been recognized as important virulence factors of diseases by urease-producing microorganisms. Ureases activate exocytosis in different mammalian cells recruiting eicosanoids and Ca2+-dependent pathways, even when their ureolytic activity is blocked by an irreversible inhibitor. Ureases are chemotactic factors recognized by neutrophils (and some bacteria), activating them and also platelets into a pro-inflammatory “status”. Secretion-induction by ureases may play a role in fungal and bacterial diseases in humans and other animals. The now recognized “moonlighting” properties of these proteins have renewed interest in ureases for their biotechnological potential to improve plant defense against pests and as potential targets to ameliorate diseases due to pathogenic urease-producing microorganisms.
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•Ureases are Ni-dependent enzymes that cleave urea into ammonia and carbon dioxide.•Ureases are multifunctional toxins with enzyme-dependent and – independent effects.•Ureases have a defense role in plants as insecticidal and antifungal agents.•Neurotoxic and pro-inflammatory effects of ureases contribute to microbial diseases.
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