Silver ions are responsible for memory impairment induced by oral administration of silver nanoparticles.

Increasing use of silver nanoparticles (AgNPs) results in increased human exposure. AgNPs are able to cross brain-blood barrier and are a risk factor for the brain. Thus, we hypothesized that AgNPs exposure might affect hippocampal dependent memory, which required cognitive coordination processes. To verify the assumption, in this study we evaluated the effects of orally administered bovine serum albumin (BSA)-coated AgNPs on spatial memory, which engage cognitive coordination processes for on-going stimuli segregation. Rats following 28 days of oral administration with 1 mg/kg (n = 10) or 30 mg/kg (n = 10) BSA-AgNPs or saline, a control groups (n = 10, n = 8), were tested with an active place avoidance task in the Carousel Maze test. The study revealed significant impairment of long- and short-term memory, irrespectively of dose of AgNPs, whereas non-cognitive activity was on a similar level. We found significantly higher content of silver in the hippocampus in comparison to the lateral cortex. No silver was found in the cerebellum and the frontal cortex. The nanoSIMS analysis reveal a weak signal of silver in the hippocampus of AgNPs treated animals that should be attributed to the presence of silver in ionic form rather than AgNPs. Our findings indicate that oral exposure to a low dose AgNPs induces detrimental effect on memory and cognitive coordination processes. The presence of silver ions rather than AgNPs in different brain regions, in particular the hippocampus, suggests crucial role of silver ions in AgNPs-induced impairment of the higher brain functions.

Dataset of liver proteins of eu- and hypothyroid rats affected in abundance by any of three factors: in vivo exposure to hexabromocyclododecane (HBCD), thyroid status, gender differences.

Male Wistar rats with different thyroid status (eu-, hypothyroid) were exposed to 0, 3 or 30 mg/kg body weight of the flame retardant HBCD for 7 days and obtained data compared with a previous study in females, "Hexabromocyclododecane (HBCD) induced changes in the liver proteome of eu- and hypothyroid female rats" (Miller et al., 2016) [1]. Specifically, proteomic investigation of liver protein patterns obtained by 2D-DIGE was performed and differences between animals groups recorded, based on the factors exposure, thyroid status and gender. All proteins with significantly changed abundance in any of these comparisons were identified by mass spectrometry. General, hormone and proteomic data of both the present and the previous studies are discussed in Miller et al. (2016) [1] and in "Gender specific differences in the liver proteome of rats exposed to hexabromocyclododecane (HBCD)" Miller et al. (2016) [2].

Dataset of liver proteins changed in eu- and hypothyroid female rats upon in vivo exposure to hexabromocyclododecane (HBCD).

Female Wistar rats with different thyroid status (eu-, hypothyroid) were exposed to 0, 3 or 30 mg/kg body weight of the flame retardant HBCD for 7 days. Changes in protein patterns obtained by 2D-DIGE were evaluated, and different animal groups compared taking into account their exposure and thyroid status. Proteins significantly altered in abundance in any of these comparisons were identified by mass spectrometry. These data, together with hormone data of the animals, are discussed in "Hexa-bromocyclododecane (HBCD) induced changes in the liver proteome of eu- and hypothyroid female rats" (Miller et al., 2016) [1].

Hexabromocyclododecane (HBCD) induced changes in the liver proteome of eu- and hypothyroid female rats.

Hexabromocyclododecane (HBCD) is a brominated flame retardant known for its low acute toxicity as observed in animal experiments. However, HBCD exposure can affect liver functioning and thyroid hormone (TH) status. As exact mechanisms are unknown and only limited toxicological data exists, a gel-based proteomic approach was undertaken. In a eu- and hypothyroid female rat model, rats were exposed to 3 and 30 mg/kg bw/day HBCD for 7 days via their diet, and exposure was related to a range of canonical endpoints (hormone status, body weight) available for these animals. Alterations in the liver proteome under HBCD exposure were determined in comparison with patterns of control animals, for both thyroid states. This revealed significantly changed abundance of proteins involved in metabolic processes (gluconeogenesis/glycolysis, amino acid metabolism, lipid metabolism), but also in oxidative stress responses, in both euthyroid and hypothyroid rats. The results provide a more detailed picture on the mechanisms involved in these alterations, e.g. at the protein level changes of the proposed influence of HBCD on the lipid metabolism. Present results show that proteomic approaches can provide further mechanistic insights in toxicological studies.

Gender specific differences in the liver proteome of rats exposed to short term and low-concentration hexabromocyclododecane (HBCD).

The influence of short term (7-day) exposure of male rats to the brominated flame retardant hexabromocyclododecane (HBCD) was studied by investigation of the liver proteome, both in euthyroid and hypothyroid rats and by comparing results with general data on animal physiology and thyroid hormone, leptin, insulin and gonadotropin concentrations determined in parallel. Proteome analysis of liver tissue by two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) revealed that only small protein pattern changes were induced by exposure in males, on just a few proteins with different functions and not involved in pathways in common. This is in contrast to previous findings in similarly exposed eu- and hypothyroid female rats, where general metabolic pathways had been shown to be affected. The largest gender-dependent effects concerned basal concentrations of liver proteins already in control and hypothyroid animals, involving mainly the pathways which were also differently affected by HBCD exposure. Among them were differences in lipid metabolism, which - upon exposure to HBCD - may also be the reason for the considerably higher ratio of γ-HBCD accumulated in white adipose tissue of exposed female rats compared to males. The results further elucidate the already suggested different sensitivity of genders towards HBCD exposure on the protein level, and confirm the need for undertaking toxicological animal experiments in both genders.

A pilot study on the feasibility of European harmonized human biomonitoring: Strategies towards a common approach, challenges and opportunities.

In 2004 the European Commission and Member States initiated activities towards a harmonized approach for Human Biomonitoring surveys throughout Europe. The main objective was to sustain environmental health policy by building a coherent and sustainable framework and by increasing the comparability of data across countries. A pilot study to test common guidelines for setting up surveys was considered a key step in this process. Through a bottom-up approach that included all stakeholders, a joint study protocol was elaborated. From September 2011 till February 2012, 17 European countries collected data from 1844 mother-child pairs in the frame of DEMOnstration of a study to COordinate and Perform Human Biomonitoring on a European Scale (DEMOCOPHES).(1) Mercury in hair and urinary cadmium and cotinine were selected as biomarkers of exposure covered by sufficient analytical experience. Phthalate metabolites and Bisphenol A in urine were added to take into account increasing public and political awareness for emerging types of contaminants and to test less advanced markers/markers covered by less analytical experience. Extensive efforts towards chemo-analytical comparability were included. The pilot study showed that common approaches can be found in a context of considerable differences with respect to experience and expertize, socio-cultural background, economic situation and national priorities. It also evidenced that comparable Human Biomonitoring results can be obtained in such context. A European network was built, exchanging information, expertize and experiences, and providing training on all aspects of a survey. A key challenge was finding the right balance between a rigid structure allowing maximal comparability and a flexible approach increasing feasibility and capacity building. Next steps in European harmonization in Human Biomonitoring surveys include the establishment of a joint process for prioritization of substances to cover and biomarkers to develop, linking biomonitoring surveys with health examination surveys and with research, and coping with the diverse implementations of EU regulations and international guidelines with respect to ethics and privacy.

Detection of multiple mycotoxin occurrences in soy animal feed by traditional mycological identification combined with molecular species identification.

Soy products are a main component of animal feed. Because mycotoxins may harm farm animals, undermining productivity and health, a mycological and toxigenic screening was carried out on 36 batches used in animal feed, collected in 2008, 2009 and 2010 in Italy. The investigated mycoflora of a subset of soy seed (n = 6) suggested that Aspergillus spp. and Fusarium spp. frequently colonize soy seeds. Aflatoxins, fumonisins and deoxynivalenol were detected in 88.9%, 72.2% and 30.6% of samples, respectively. Co-occurrence of at least two toxins was observed in 72% of cases. The molecular analysis of the Fusarium spp. population identified Fusarium verticillioides as potential producers of fumonisins, but no known deoxynivalenol producers were detected. It is suggested that the widespread presence of toxins can be due to non-optimal storing conditions of the feed. Moreover, our results suggest that mycotoxin thresholds should be adapted to consider the frequent case of toxin co-occurrence. This approach would better reflect the real toxigenic risk of feedstuffs.

Interpreting biomarker data from the COPHES/DEMOCOPHES twin projects: Using external exposure data to understand biomarker differences among countries.

In 2011 and 2012, the COPHES/DEMOCOPHES twin projects performed the first ever harmonized human biomonitoring survey in 17 European countries. In more than 1800 mother-child pairs, individual lifestyle data were collected and cadmium, cotinine and certain phthalate metabolites were measured in urine. Total mercury was determined in hair samples. While the main goal of the COPHES/DEMOCOPHES twin projects was to develop and test harmonized protocols and procedures, the goal of the current paper is to investigate whether the observed differences in biomarker values among the countries implementing DEMOCOPHES can be interpreted using information from external databases on environmental quality and lifestyle. In general, 13 countries having implemented DEMOCOPHES provided high-quality data from external sources that were relevant for interpretation purposes. However, some data were not available for reporting or were not in line with predefined specifications. Therefore, only part of the external information could be included in the statistical analyses. Nonetheless, there was a highly significant correlation between national levels of fish consumption and mercury in hair, the strength of antismoking legislation was significantly related to urinary cotinine levels, and we were able to show indications that also urinary cadmium levels were associated with environmental quality and food quality. These results again show the potential of biomonitoring data to provide added value for (the evaluation of) evidence-informed policy making.

The added value of proteomics for toxicological studies.

Proteomics has the potential to elucidate complex patterns of toxic action attributed to its unique holistic a posteriori approach. In the case of toxic compounds for which the mechanism of action is not completely understood, a proteomic approach may provide valuable mechanistic insight. This review provides an overview of currently available proteomic techniques, including examples of their application in toxicological in vivo and in vitro studies. Future perspectives for a wider application of state-of-the-art proteomic techniques in the field of toxicology are discussed. The examples concern experiments with dioxins, polychlorinated biphenyls, and polybrominated diphenyl ethers as model compounds, as they exhibit a plethora of sublethal effects, of which some mechanisms were revealed via successful proteomic studies. Generally, this review shows the added value of including proteomics in a modern tool box for toxicological studies.

Moniliformin in Norwegian grain.

Norwegian grain samples (73 oats, 75 barley, 83 wheat) from the 2000-02 growing seasons were examined for contamination with moniliformin, and the association between the fungal metabolite and the number of kernels infected with common Fusaria was investigated. Before quantification of moniliformin using ion pairing reversed-phase high-performance liquid chromatography with diode array ultraviolet light detection, all samples were extracted using acetonitrile/water (84/16) and disposable strong anion exchange columns used for clean up. The limit of detection was 40 microg kg(-1). Moniliformin was found in 25, 32 and 76% of the barley, oats and wheat samples, respectively. The maximum concentrations of moniliformin in barley, oats and wheat were 380, 210 and 950 microg kg(-1), respectively. At the same time, the prevalence and infection level of the moniliformin-producing F. avenaceum/arthrosporioides was as high as 100 and >53% on average, respectively. Moniliformin concentrations were significantly correlated to the variables grain species, growing season and infection with F. avenaceum/arthrosporioides and F. culmorum. The survey indicates that the prevalence of moniliformin in Norwegian grain is high, especially in wheat. On the other hand, field conditions in Norway do not seem to favour contamination of grain with high levels of moniliformin.

Latex laboratory-gloves: an unexpected pitfall in amphibian toxicity assays with tadpoles.

This study examined the unexpected toxic effects of protective latex laboratory gloves on developing amphibians. Mortality after exposure to rinsing water from the outside of the gloves was observed in Xenopus laevis and Rana temporaria, with R. temporaria being more sensitive. This phenomenon was further confirmed using the microtiter-version of the Microtox-Assay, an in vitro assay for general toxicity. Latex gloves from the specific brand used in the experiment, in which the toxicity to tadpoles was observed for the first time, showed the highest toxicity of all materials and brands tested. Due to the high responsiveness of amphibian tadpoles to latex-glove contaminated rinsing water, special care is necessary when cleaning aquaria during toxicological experiments with amphibians as otherwise results may be biased.

Effects of oral exposure to polychlorinated biphenyls (PCBs) on the development and metamorphosis of two amphibian species (Xenopus laevis and Rana temporaria).

This study examined the effects of polychlorinated biphenyls (PCBs) on development of families of amphibians using the African clawed frog (Xenopus laevis) and the European common frog (Rana temporaria). Amphibians were orally exposed to the technical PCB-mixture Clophen A50 or to the non-ortho-3,3',4,4',5-CB congener (PCB 126) either for a 10-day period or until metamorphosis. Occurrence and rate of malformations, mortality, period until metamorphosis and thyroid hormone levels were measured. Mortality increased in a dose-dependent manner, as did the rates of malformation. Time until metamorphic transformation was prolonged and the weight of froglets was increased. Although not statistically significant, thyroid hormone levels were also lowered. PHAHs such as PCBs may affect important aspects of amphibian fitness and may influence amphibian reproductive success.

Delayed effects of pre- and early-life time exposure to polychlorinated biphenyls on tadpoles of two amphibian species (Xenopus laevis and Rana temporaria).

This study examined the effects of polychlorinated biphenyls (PCBs) on the development of amphibians using Xenopus laevis and Rana temporaria as experimental animals. Amphibians were exposed at different life stages and via different routes to the technical mixtures Clophen A50 and Aroclor 1254 or to a non-ortho PCB congener (PCB 126). The effects of PCB exposure in amphibians, such as mortality, number and pattern of malformations, or body weight at the end of successful metamorphosis of tadpoles, depends on the route, the point of time of exposure during the complex life cycle of amphibians, and the length of the observation period. Retinoid concentrations were significantly altered in PCB dosed embryos. Presently used early-life time test systems such as the FETAX assay may underestimate toxic effects of compounds with long term response such as PCBs on amphibians.

Two-dimensional electrophoresis for the study of blood/serum proteins of the otter, an endangered species.

Studies on serum/blood samples from European otters (Lutra lutra), a species under protection in most countries, were undertaken. Building of a two-dimensional electrophoresis (2-DE) protein identification map was started, identifying serum proteins by pattern comparison with cat or human serum protein maps and by immunoblotting using cross-reacting antibodies against the respective human serum proteins. The capture of endangered species is very restricted, thus making fresh samples almost unavailable; most investigations therefore had to be performed on samples collected from animals found dead. Patterns obtained from specimens of this source were compared to the established pattern of serum proteins and of blood or liver cells. Some of the major differences observed can be explained by contamination with cellular proteins and/or the onset of lytic processes generating breakdown products, as shown by preliminary in vitro experiments. Better knowledge of "normal" serum protein patterns and interfering products will facilitate interpretation of data collected from samples with a less defined history.

Forensics on wild animals: differentiation between otter and pheasant blood using electrophoretic methods.

Electrophoretic techniques were used to prove illegal hunting of a protected species as small amounts of dried blood stains could be clearly identified as of otter origin. Species differentiation between the otter (Lutra lutra) and pheasant (Phasianus colchicus) was based mainly on small differences in electrophoretic mobilities of the respective albumins and hemoglobins in one-dimensional separations. Additional differences in minor proteins of the two species were revealed by two-dimensional electrophoresis. Electrophoresis thus also proved to be a valuable tool for forensic purposes.