Cytotoxicity of 19 Pesticides in Rainbow Trout Gill, Liver, and Intestinal Cell Lines

The rainbow trout gill cell line (RTgill-W1), via test guideline 249 of the Organisation for Economic Co-operation and Development, has been established as a promising New Approach Methodology, although to advance confidence in the method more case studies are needed that: 1) expand our understanding of applicability domains (chemicals with diverse properties); 2) increase methodological throughput (96-well format); and 3) demonstrate biological relevance (in vitro to in vivo comparisons; gill vs. other cells). Accordingly, the objective of our study was to characterize the cytotoxicity of 19 pesticides against RTgill-W1 cells, and also liver (RTL-W1) and gut epithelial (RTgutGC) cell lines, and then to compare the in vitro and in vivo data. Of the 19 pesticides tested, 11, 9, and 8 were cytotoxic to the RTgill-W1, RTL-W1, and RTgutGC cells, respectively. Six pesticides (carbaryl, chlorothalonil, chlorpyrifos, dimethenamid-P, metolachlor, and S-metolachlor) were cytotoxic to all three cell lines. Aminomethylphosphonic acid, chlorantraniliprole, dicamba, diquat, imazethapyr, and permethrin exhibited cell-line-specific toxicity. No cytotoxic responses were observed for three herbicides (atrazine, glyphosate, and metribuzin) and four insecticides (clothianidin, diazinon, imidacloprid, and thiamethoxam). When cytotoxicity was measured, there was a strong correlation (rs  = 0.9, p < 0.0001) between in vitro median effect concentration (EC50) values (based on predicted concentrations using the In Vitro Mass Balance Model Equilibrium Partitioning (IV-MBM EQP) Ver. 2.1) derived from RTgill-W1 and RTL-W1 cells with in vivo median lethal concentration (LC50) values from 96-h acute toxicity studies with trout. In all 28 cases, the in vitro EC50 was within 18-fold of the in vivo LC50. These data help increase our understanding of the ecotoxicological domains of applicability for in vitro studies using cultured rainbow trout cells, while also demonstrating that these assays performed well in a 96-well format and have promise to yield data of biological relevance. Environ Toxicol Chem 2024;00:1-13. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Hepatic Transcriptomic Responses to Ethinylestradiol in Embryonic Japanese Quail and Double-Crested Cormorant

Understanding species differences in sensitivity to toxicants is a critical issue in ecotoxicology. We recently established that double-crested cormorant (DCCO) embryos are more sensitive than Japanese quail (JQ) to the developmental effects of ethinylestradiol (EE2). We explored how this difference in sensitivity between species is reflected at a transcriptomic level. The EE2 was dissolved in dimethyl sulfoxide and injected into the air cell of eggs prior to incubation at nominal concentrations of 0, 3.33, and 33.3 µg/g egg weight. At midincubation (JQ 9 days; DCCO 16 days), livers were collected from five embryos/treatment group for RNA sequencing. Data were processed and analyzed using EcoOmicsAnalyst and ExpressAnalyst. The EE2 exposure dysregulated 238 and 1,987 genes in JQ and DCCO, respectively, with 78 genes in common between the two species. These included classic biomarkers of estrogen exposure such as vitellogenin and apovitellenin. We also report DCCO-specific dysregulation of Phase I/II enzyme-coding genes and species-specific transcriptional ontogeny of vitellogenin-2. Twelve Kyoto Encyclopedia of Genes and Genomes pathways and two EcoToxModules were dysregulated in common in both species including the peroxisome proliferator-activated receptor (PPAR) signaling pathway and fatty acid metabolism. Similar to previously reported differences at the organismal level, DCCO were more responsive to EE2 exposure than JQ at the gene expression level. Our description of differences in transcriptional responses to EE2 in early life stage birds may contribute to a better understanding of the molecular basis for species differences. Environ Toxicol Chem 2024;00:1-12. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Comparing Transcriptomic Responses to Chemicals Across Six Species Using the EcoToxChip RNASeq Database

The EcoToxChip project includes RNA-sequencing data from experiments involving model (Japanese quail, fathead minnow, African clawed frog) and ecological (double-crested cormorant, rainbow trout, northern leopard frog) species at multiple life stages (whole embryo and adult) exposed to eight chemicals of environmental concern known to perturb a wide range of biological systems (ethinyl estradiol, hexabromocyclododecane, lead, selenomethionine, 17β trenbolone, chlorpyrifos, fluoxetine, and benzo[a]pyrene). The objectives of this short communication were to (1) present and make available this RNA-sequencing database (i.e., 724 samples from 49 experiments) under the FAIR principles (FAIR data are data which meet principles of findability, accessibility, interoperability, and reusability), while also summarizing key meta-data attributes and (2) use ExpressAnalyst (including the Seq2Fun algorithm and EcoOmicsDB) to perform a comparative transcriptomics analysis of this database focusing on baseline and differential transcriptomic changes across species-life stage-chemical combinations. The database is available in NCBI GEO under accession number GSE239776. Across all species, the number of raw reads per sample ranged between 13 and 58 million, with 30% to 79% of clean reads mapped to the "vertebrate" subgroup database in EcoOmicsDB. Principal component analyses of the reads illustrated separation across the three taxonomic groups as well as some between tissue types. The most common differentially expressed gene was CYP1A1 followed by CTSE, FAM20CL, MYC, ST1S3, RIPK4, VTG1, and VIT2. The most common enriched pathways were metabolic pathways, biosynthesis of cofactors and biosynthesis of secondary metabolites, and chemical carcinogenesis, drug metabolism, and metabolism of xenobiotics by cytochrome P450. The RNA-sequencing database in the present study may be used by the research community for multiple purposes, including, for example, cross-species investigations, in-depth analyses of a particular test compound, and transcriptomic meta-analyses. Environ Toxicol Chem 2024;00:1-6. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Characterizing Variability and Uncertainty Associated with Transcriptomic Dose-Response Modeling

Transcriptomics dose-response analysis (TDRA) has emerged as a promising approach for integrating toxicogenomics data into a risk assessment context; however, variability and uncertainty associated with experimental design are not well understood. Here, we evaluated n = 55 RNA-seq profiles derived from Japanese quail liver tissue following exposure to chlorpyrifos (0, 0.04, 0.1, 0.2, 0.4, 1, 2, 4, 10, 20, and 40 μg/g; n = 5 replicates per group) via egg injection. The full dataset was subsampled 637 times to generate smaller datasets with different dose ranges and spacing (designs A-E) and number of replicates (n = 2-5). TDRA of the 637 datasets revealed substantial variability in the gene and pathway benchmark doses, but relative stability in overall transcriptomic point-of-departure (tPOD) values when tPODs were calculated with the "pathway" and "mode" methods. Further, we found that tPOD values were more dependent on the dose range and spacing than on the number of replicates, suggesting that optimal experimental designs should use fewer replicates (n = 2 or 3) and more dose groups to reduce uncertainty in the results. Finally, tPOD values ranged by over ten times for all surveyed experimental designs and tPOD types, suggesting that tPODs should be interpreted as order-of-magnitude estimates.

Consideration of metabolomics and transcriptomics data in the context of using avian embryos for toxicity testing

Early-life stage (ELS) avian toxicity tests have been proposed as a more ethical alternative to traditional standardized tests with adult birds. At the same time, 'omics approaches are gaining traction in the field of avian toxicology, but little has been done to characterize the metabolome and transcriptome at different life stages. The present study uses 'omics data from toxicity tests of 8 environmental chemicals in ELS and adult Japanese quail (Coturnix japonica) to address this data gap. Previous analyses of these data focused on responses to each of the individual chemicals. Here, we consider data from all studies to describe variation in the metabolome and transcriptome between life stages and across independent experiments, irrespective of chemical treatment. Of the 230 metabolites detected in liver, 163 were shared between the two life stages. However, many of the targeted bile acids that were present in the adult liver were absent from ELS samples. For the transcriptome, >90% of the 18,364 detected transcripts were common to both life stages. Based on the 213 genes solely detected in ELS liver, the neuroactive ligand-receptor interaction pathway was significantly enriched. Multivariate and hierarchical clustering analyses revealed that variability among independent experiments was higher for the adult than the ELS studies at both the metabolomic and transcriptomic levels. Our results indicate concordance of the two approaches, with less variation between independent experiments in the ELS metabolome and transcriptome than in adults, lending support for the use of ELS as an alternative toxicity testing strategy.

Associations between combinations of job demands and job control among 6,16,818 people aged 55-64 in paid work with their labour market status 11 years later: a prospective cohort study

BACKGROUND

Given current discussions about extending working lives, more knowledge is needed on working conditions associated with labour market status in older age.

OBJECTIVE

To explore associations between combinations of job demands and job control among workers aged 55-64 years and their labour market status 11 years later.

METHODS

A population-based prospective cohort study using nationwide register data. The 616,818 individuals in Sweden aged 55-64 who in 2001 were in paid work were categorised using a job exposure matrix based on tertiles (reference = medium control/medium demands). Participants were followed up in 2012 regarding their main labour market status (paid work, old-age pension, no income/social assistance, sickness absence/disability pension, emigrated, dead; reference = old-age pension) using multinomial logistic regression for odds ratios (OR) and 95% confidence intervals (CI). The fully adjusted analyses included adjustment for sociodemographic factors and unemployment or sickness absence/disability pension for more than half the year in 2001.

RESULTS

Those in occupations with low job control at baseline were less likely to be in paid work at follow-up (OR low demands/low control 0.74, CI 0.71-0.78; high demands/low control 0.81, CI 0.75-0.87). Those in occupations with baseline high demands were less likely to have no income/social assistance at follow-up (OR high demands/low control 0.71, CI 0.52-0.96; high demands/high control 0.59, CI 0.47-0.75).

CONCLUSION

Job demands and control when aged 55-64 were associated with labour market status 11 years later: high control was associated with greater chance of being in paid work, and high demands were associated with lower risk of no income/social assistance.

Using Transcriptomics and Metabolomics to Understand Species Differences in Sensitivity to Chlorpyrifos in Japanese Quail and Double-Crested Cormorant Embryos

Modern 21st-century toxicity testing makes use of omics technologies to address critical questions in toxicology and chemical management. Of interest are questions relating to chemical mechanisms of toxicity, differences in species sensitivity, and translation of molecular effects to observable apical endpoints. Our study addressed these questions by comparing apical outcomes and multiple omics responses in early-life stage exposure studies with Japanese quail (Coturnix japonica) and double-crested cormorant (Phalacrocorax auritus), representing a model and ecological species, respectively. Specifically, we investigated the dose-dependent response of apical outcomes as well as transcriptomics and metabolomics in the liver of each species exposed to chlorpyrifos, a widely used organophosphate pesticide. Our results revealed a clear pattern of dose-dependent disruption of gene expression and metabolic profiles in Japanese quail but not double-crested cormorant at similar chlorpyrifos exposure concentrations. The difference in sensitivity between species was likely due to higher metabolic transformation of chlorpyrifos in Japanese quail compared to double-crested cormorant. The most impacted biological pathways after chlorpyrifos exposure in Japanese quail included hepatic metabolism, oxidative stress, endocrine disruption (steroid and nonsteroid hormones), and metabolic disease (lipid and fatty acid metabolism). Importantly, we show consistent responses across biological scales, suggesting that significant disruption at the level of gene expression and metabolite profiles leads to observable apical responses at the organism level. Our study demonstrates the utility of evaluating effects at multiple biological levels of organization to understand how modern toxicity testing relates to outcomes of regulatory relevance, while also highlighting important, yet poorly understood, species differences in sensitivity to chemical exposure. Environ Toxicol Chem 2021;40:3019-3033. © 2021 SETAC.

Health of older people in places and work-related outcomes: are all health indicators equal?

Background

Health has been posited as an explanation for why older people who live in more disadvantaged areas have worse work-related outcomes. The policy implication being that if a higher proportion of older persons in a place had better health, those labour markets would be better for everyone. No literature exists on this topic.

Methods

Data was used from 428,646 members of the Office for National Statistics Longitudinal Study (LS) who were 16-74y at the 2011 census and had information on employment status, economic activity and occupational socioeconomic classification. Generalised Structural Equation Modelling was used to examine whether each of the three work-related outcomes were equally related to nine 2011 local authority district (LAD)-level older adult health indicators.

Results

In age-adjusted analysis, all nine LAD-level health indicators (modelled in terciles) were associated with all three work outcomes. However, strengths of association varied both across and within each outcome. For example, the strongest associations were for being ‘sick or disabled' versus ‘In employment'. If an LS member lived in the ‘unhealthiest' versus ‘healthiest' third of LADs, associations varied between a high of 2.74 higher odds (95% CI: 2.53,2.95) for long-term illness and a low of 2.10 higher odds (1.89,2.32) for disease-free life expectancy at age 50y. The weakest associations were for part-time versus full-time employment: ranging from life expectancy at birth at 1.29 (1.21,1.38) to healthy-life expectancy at age 50y: 1.18 (1.10,1.27). Adjustment for individual health reduced, but did not eliminate, associations. Sensitivity analysis showed robustness to area health indicators being assessed for sub-groups of older people (ages 50-64 & 65-74), genders and a reduced sample of older persons (50-74y) only.

Conclusions

Health of older people in places is associated with work outcomes of people in those places; both the older people themselves and the wider community.

Key messages

At a place level, health and work outcomes are linked. Strengths of association between place-level health and work outcomes will depend on the health measure used.

Trends in associations between sickness absence, disability pension and paid work after age 65

Aim

The increasing workforce participation at higher ages may impact social insurance systems, however, this has hardly been studied at all. We investigated associations between sociodemographic factors, prior sickness absence, and prior disability pension, with being in paid work after age 65 and to what extent they then had any sickness absence, and if such associations changed over time.

Methods

We conducted three prospective cohort studies. We used longitudinal data from three nationwide registers linked at individual level covering all residents in Sweden who turned 65 years in 2000, 2005, or 2010 (N = 50,000, 68,000, and 99,000, respectively). Logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI) for the association between sickness absence and disability pension when aged 60-64 and a) being in paid work when aged 66-71, and b) having sickness absence when aged 66-71 among those in paid work, adjusted for sociodemographic variables in each of the three cohorts.

Results

Although the percentage of individuals in paid work when aged 66-71 increased substantially between the cohorts (2000 cohort 28.7%, 2005 cohort 39.5%, 2010 cohort 48.2%), associations of sociodemographic factors with being in paid work or having sickness absence when aged 66-71 remained steady. Both sickness absence and disability pension when aged 60-64 were negatively associated with working past 65 (sickness absence 2000 cohort OR 0.86, 95% CI 0.82-0.90; 2010 cohort OR 0.89, CI 0.87-0.92 - disability pension 2000 cohort OR 0.41, 0.39-0.44; 2010 cohort OR 0.36, CI 0.35-0.38). Sickness absence when aged 60-64 was positively associated with sickness absence after 65 (2000 cohort OR 2.16, CI 1.86-2.51; 2010 cohort OR 2.15, CI 1.98-2.33) while disability pension was negatively associated with sickness absence after 65 (2000 cohort OR 0.69, CI 0.52-0.92; 2010 cohort OR 0.83, CI 0.68-1.01).

Key messages

Rates of people in paid work &gt;65 increased much from 2000 to 2010; their sickness absence increased marginally, while associations of sociodemographic factors with paid work did not change over time. Prior sickness absence was associated with paid work and sickness absence after age 65, while disability pension before age 65 was associated with less sickness absence after 65.

The role of loneliness in the development of depressive symptoms among partnered dementia caregivers: Evidence from the English Longitudinal Study of Aging

Background

Depressive symptoms are highly prevalent among partnered dementia caregivers, but the mechanisms are unclear. This study examined the mediating role of loneliness in the association between dementia and other types of care on subsequent depressive symptoms.

Methods

Prospective data from partnered caregivers were drawn from the English Longitudinal Study of Aging. The sample consisted of 4,672 partnered adults aged 50–70 living in England and Wales, followed up between 2006–2007 and 2014–2015. Caregiving was assessed across waves 3 (2006–2007), 4 (2008–2009), and 5 (2010–2011), loneliness at wave 6 (2012–2013), and subsequent depressive symptoms at wave 7 (2014–15). Multivariable logistic regression models were used to assess the association between caregiving for dementia and depressive symptoms compared to caregiving for other illnesses (e.g., diabetes, coronary heart disease (CHD), cancer, and stroke). Binary mediation analysis was used to estimate the indirect effects of caregiving on depressive symptoms via loneliness.

Results

Care for a partner with dementia was associated with higher odds of depressive symptoms at follow-up compared to those not caring for a partner at all (odds ratio [OR] = 2.6, 95% confidence intervals [CI]: 1.4, 5.1). This association was partially mediated by loneliness (34%). Care for a partner with other conditions was also associated with higher odds of depressive symptoms compared to non-caregiving partners (OR = 1.7, 95% CI: 1.2, 2.5), but there was no evidence of an indirect pathway via loneliness.

Conclusion

Loneliness represents an important contributor to the relationship between dementia caregiving and subsequent depressive symptoms; therefore, interventions to reduce loneliness among partnered dementia caregivers should be considered.

Ultrafast functional profiling of RNA-seq data for nonmodel organisms

Computational time and cost remain a major bottleneck for RNA-seq data analysis of nonmodel organisms without reference genomes. To address this challenge, we have developed Seq2Fun, a novel, all-in-one, ultrafast tool to directly perform functional quantification of RNA-seq reads without transcriptome de novo assembly. The pipeline starts with raw read quality control: sequencing error correction, removing poly(A) tails, and joining overlapped paired-end reads. It then conducts a DNA-to-protein search by translating each read into all possible amino acid fragments and subsequently identifies possible homologous sequences in a well-curated protein database. Finally, the pipeline generates several informative outputs including gene abundance tables, pathway and species hit tables, an HTML report to visualize the results, and an output of clean reads annotated with mapped genes ready for downstream analysis. Seq2Fun does not have any intermediate steps of file writing and loading, making I/O very efficient. Seq2Fun is written in C++ and can run on a personal computer with a limited number of CPUs and memory. It can process >2,000,000 reads/min and is >120 times faster than conventional workflows based on de novo assembly, while maintaining high accuracy in our various test data sets.

Addressing unpredictability may be the key to improving performance with current clinically prescribed myoelectric prostheses

The efferent control chain for an upper-limb myoelectric prosthesis can be separated into 3 key areas: signal generation, signal acquisition, and device response. Data were collected from twenty trans-radial myoelectric prosthesis users using their own clinically prescribed devices, to establish the relative impact of these potential control factors on user performance (user functionality and everyday prosthesis usage). By identifying the key factor(s), we can guide future developments to ensure clinical impact. Skill in generating muscle signals was assessed via reaction times and signal tracking. To assess the predictability of signal acquisition, we inspected reaction time spread and undesired hand activations. As a measure of device response, we recorded the electromechanical delay between electrode stimulation and the onset of hand movement. Results suggest abstract measures of skill in controlling muscle signals are poorly correlated with performance. Undesired activations of the hand or incorrect responses were correlated with almost all kinematics and gaze measures suggesting unpredictability is a key factor. Significant correlations were also found between several measures of performance and the electromechanical delay; however, unexpectedly, longer electromechanical delays correlated with better performance. Future research should focus on exploring causes of unpredictability, their relative impacts on performance and interventions to address this.

Effects of acute stressors experienced by five strains of layer breeders on measures of stress and fear in their offspring

Stressors experienced by layer breeders during egg production can lead to changes in the egg hormone content, potentially impacting their offspring, the commercial layers. Genetic differences might also affect the offspring's susceptibility to maternal experiences. In this study, we tested if maternal stress affects measures of stress and fear in five strains of layer breeders: commercial brown 1 & 2, commercial white 1 & 2 and a pure line White Leghorn. Each strain was equally separated into two groups: "Maternal Stress" (MS), where hens were subjected to a series of 8 consecutive days of acute psychological stressors, and "Control," which received routine husbandry. Additional eggs from Control were injected either with corticosterone diluted in a vehicle solution ("CORT") or just "Vehicle." Stress- and fear-responses of the offspring were measured in a plasma corticosterone test and a combined human approach and novel object test. While the stress treatments did not  affect the measured endpoints in the offspring, significant strain differences were found. The offspring of the white strains showed a higher physiological response compared to brown strains and the White 2 offspring was the least fearful strain in the human approach test. Our study found that neither the acute psychological stressors experienced by layer breeders nor the egg injections of corticosterone affected the parameters tested in their offspring. Post hoc power analyses suggest that the lack of treatment effects might be due to a small sample size (type II error). Although studies on larger flocks of layers are still needed, our results provide an initial understanding of an important subject, as in poultry production, layer breeders are often subjected to short-term stressors. In addition, our results suggest the dissociation between the physiological and behavioural parameters of stress response in laying hens, showing that increased concentrations of plasma corticosterone in response to stress might not be directly associated with high levels of fear.

Job demands/control among people in paid work age 55-64 and their labour market status 11 years later

Background

As discussions about extending working lives are ongoing, more knowledge is warranted on working conditions that are associated with labour market status in older age.

Aim

Among employees aged 55-64 years, associations between job demands/job control with their labour market status 11 years later were explored.

Methods

A population-based prospective cohort study using a job exposure matrix (JEM) and nationwide register data. All 616,818 individuals in Sweden who in 2001 were in paid work and aged 55-64, were assigned JEM values for job demands/control that were categorized into tertiles resulting in nine combinations of job demands/control (reference=medium control/medium demands). Follow-up was in 2012 regarding labour market status (paid work, old-age pension, low/no income, sickness absence emigrated, dead). Odds ratios (OR) and 95% confidence intervals (CI) were calculated using multinomial logistic regression (reference category=old-age pension) with adjustment for educational level, age, birth country, family situation and type of living area.

Results

Women in occupations with high control (OR low demands/high control 1.21, CI 1.06-1.39, medium demands/high control 1.32, CI 1.20-1.46, high demands/high control 1.29, CI 1.20-1.37); and men in occupations with high demands/high control (OR 1.11, CI 1.02-1.21) were more likely to be in paid work. Those in occupations with high demands at baseline were less likely to have low/no income at follow-up (OR women high demands/medium control 0.51, CI 0.37-0.68, high demands/high control 0.68, CI 0.50-0.92; men high demands/medium control 0.55, CI 0.31-0.96, high demands/high control 0.47, CI 0.32-0.74.

Conclusions

High job control combined with any level of demands for women and high demands for men aged 55-64 in 2001 were associated with higher OR of having main income from paid work in 2012, and high job demands combined with any level of job control were associated with lower OR of low/no income.

Key messages

Combinations of job demands and job control among workers aged 55-64 years in 2001 were associated with labour market situations in 2012. Using a job exposure matrix divided into tertiles allows for greater detail in measuring high, medium, and low demands and control than methods used in previous studies.

Cumulative effects of cadmium and natural stressors (temperature and parasite infection) on molecular and biochemical responses of juvenile rainbow trout

The simultaneous presence of natural and anthropogenic stressors in aquatic ecosystems can challenge the identification of factors causing decline in fish populations. These stressors include chemical mixtures and natural abiotic and biotic factors such as water temperature and parasitism. Effects of cumulative stressors may vary from antagonism to synergism at the organismal or population levels and may not be predicted from exposure to individual stressors. This study aimed to evaluate the combined effects of chronic exposure to cadmium (Cd) and elevated water temperature (23 °C) or parasite infection in juvenile rainbow trout (Oncorhynchus mykiss) using a multi-level biological approach, including RNA-sequencing. Fish were exposed to diet-borne Cd (6 μg Cd/g wet feed), individually and in combination with thermal (23 °C) or parasitic stressors, for 28 days. The parasite challenge consisted of a single exposure to glochidia (larvae) of the freshwater mussel (Strophitus undulatus), which encysts in fish gills, fins and skin. Results indicated lower fish length, weight, and relative growth rate in fish exposed to a higher water temperature (23 °C). Body condition and hepatosomatic index of trout were, however, higher in the 23 °C temperature treatment compared to the control fish kept at 15 °C. Exposure to thermal stress or parasitism did not influence tissue Cd bioaccumulation. More than 700 genes were differentially transcribed in fish exposed to the individual thermal stress treatment. However, neither Cd exposure nor parasite infection affected the number of differentially transcribed genes, compared to controls. The highest number of differentially transcribed genes (969 genes) was observed in trout exposed to combined Cd and high temperature stressors; these genes were mainly related to stress response, protein folding, calcium metabolism, bone growth, energy metabolism, and immune system; functions overlapped with responses found in fish solely exposed to higher water temperature. Only 40 genes were differentially transcribed when fish were exposed to Cd and glochidia and were related to the immune system, apoptosis process, energy metabolism and malignant tumor. These results suggest that dietary Cd may exacerbate the temperature stress and, to a lesser extent, parasitic infection stress on trout transcriptomic responses. Changes in the concentrations of liver ethoxyresorufin-o-deethylase, heat shock protein 70 and thiobarbituric acid reactive substances coupled to changes in the activities of cellular glutathione S-transferase and glucose-6-phosphate dehydrogenase were also observed at the cellular level. This study may help understand effects of freshwater fish exposure to cumulative stressors in a changing environment.

Female reproductive impacts of dietary methylmercury in yellow perch (Perca flavescens) and zebrafish (Danio rerio)

The purpose of this study was to evaluate the effects of environmentally relevant dietary MeHg exposures on adult female yellow perch (Perca flavescens) and female zebrafish (Danio rerio) ovarian development and reproduction. Yellow perch were used in the study for their socioeconomic and ecological importance within the Great Lakes basin, and the use of zebrafish allowed for a detailed analysis of the molecular effects of MeHg following a whole life-cycle exposure. Chronic whole life dietary exposure of F₁ zebrafish to MeHg mimics realistic wildlife exposure scenarios, and the twenty-week adult yellow perch exposure (where whole life-cycle exposures are difficult) captures early seasonal ovarian development. For both species, target dietary accumulation values were achieved prior to analyses. In zebrafish, several genes involved in reproductive processes were shown to be dysregulated by RNA-sequencing and quantitative real-time polymerase chain reaction (QPCR), but no significant phenotypic changes were observed regarding ovarian staging, fecundity, or embryo mortality. Yellow perch were exposed to dietary MeHg for 12, 16, or 20 weeks. In this species, a set of eight genes were assessed by QPCR in the pituitary, liver, and ovary, and no exposure-related changes were observed. The lack of genomic resources in yellow perch hinders the characterization of subtle molecular impacts. The ovarian somatic index, circulating estradiol and testosterone, and ovarian staging were not significantly altered by MeHg exposure in yellow perch. These results suggest that environmentally relevant MeHg exposures do not drastically reduce the reproductively important endpoints in these fish, but to capture realistic exposure scenarios, whole life-cycle yellow perch exposures are needed.

A cell-free testing platform to screen chemicals of potential neurotoxic concern across twenty vertebrate species

There is global demand for new in vitro testing tools for ecological risk assessment. The objective of the present study was to apply a set of cell-free neurochemical assays to screen many chemicals across many species in a relatively high-throughput manner. The platform assessed 7 receptors and enzymes that mediate neurotransmission of γ-aminobutyric acid, dopamine, glutamate, and acetylcholine. Each assay was optimized to work across 20 vertebrate species (5 fish, 5 birds, 7 mammalian wildlife, 3 biomedical species including humans). We tested the screening assay platform against 80 chemicals (23 pharmaceuticals and personal care products, 20 metal[loid]s, 22 polycyclic aromatic hydrocarbons and halogenated organic compounds, 15 pesticides). In total, 10 800 species-chemical-assay combinations were tested, and significant differences were found in 4041 cases. All 7 assays were significantly affected by at least one chemical in each species tested. Among the 80 chemicals tested, nearly all resulted in a significant impact on at least one species and one assay. The 5 most active chemicals were prochloraz, HgCl₂ , Sn, benzo[a]pyrene, and vinclozolin. Clustering analyses revealed groupings according to chemicals, species, and chemical-assay combinations. The results show that cell-free assays can screen a large number of samples in a short period of time in a cost-effective manner in a range of animals not easily studied using traditional approaches. Strengths and limitations of this approach are discussed, as well as next steps. Environ Toxicol Chem 2017;36:3081-3090. © 2017 SETAC.

Sick leave among people in paid work after age 65: A Swedish population-based study covering 1995, 2000, 2005 and 2010

Aims: Extending working life into older age groups is discussed in many countries. However, there is no knowledge about how this affects rates of sick leave. The aim of this work was to investigate rates of sick leave among people in paid work after retirement age and if such rates have changed over time. Methods: Swedish nationwide register data on people aged >65 years and living in Sweden in 1995, 2000, 2005 and 2010 were analysed. All people with a sufficiently high work income to be eligible for public sick leave benefits were included. The proportions in paid work and compensated rates of sick leave for people aged 66–70 and ≥71 were analysed by sex, educational level, country of birth, living area, and employment type and sector. Results: The percentage of people in paid work at ages 66–70 years increased from <10% in 1995 to 24% in 2010 and among those aged ≥71 years from 2.7% in 1995 to 3.5% in 2010. The rates of sick leave among working people aged 66–70 years were 3.3% in 1995 and 2.4% in 2010 and for people aged ≥71 years the rates of sick leave were 2.2% in 1995 and 0.2% in 2010. Women had higher rates of sick leave than men in 2005 and 2010, but lower in 1995 and 2000. In 2010, the rates of sick leave were similar between employees and the self-employed, and higher among employees in the public sector than among employees in the private sector. Conclusions: Rates of sick leave among workers aged >65 years were lower in 2010 than in 1995, despite much higher rates of labour market participation in 2010.

Developmental Methylmercury Exposure Affects Swimming Behavior and Foraging Efficiency of Yellow Perch (Perca flavescens) Larvae

Methylmercury (MeHg) is a pervasive and ubiquitous environmental neurotoxicant within aquatic ecosystems, known to alter behavior in fish and other vertebrates. This study sought to assess the behavioral effects of developmental MeHg exposure on larval yellow perch (Perca flavescens)-a nonmodel fish species native to the Great Lakes. Embryos were exposed to MeHg (0, 30, 100, 300, and 1000 nM) for 20 h and then reared to 25 days post fertilization (dpf) for analyses of spontaneous swimming, visual motor response (VMR), and foraging efficiency. MeHg exposures rendered total mercury (THg) body burdens of 0.02, 0.21, 0.95, 3.14, and 14.93 μg/g (wet weight). Organisms exposed to 1000 nM exhibited high mortality; thus, they were excluded from downstream behavioral analyses. All MeHg exposures tested were associated with a reduction in spontaneous swimming at 17 and 25 dpf. Exposure to 30 and 100 nM MeHg caused altered locomotor output during the VMR assay at 21 dpf, whereas exposure to 100 nM MeHg was associated with decreased foraging efficiency at 25 dpf. For the sake of comparison, the second-lowest exposure tested here rendered a THg burden that represents the permissible level of consumable fish in the United States. Moreover, this dose is reported in roughly two-thirds of consumable fish species monitored in the United States, according to the Food and Drug Administration. Although the THg body burdens reported here were higher than expected in the environment, our study is the first to analyze the effects of MeHg exposure on fundamental survival behaviors of yellow perch larvae and advances in the exploration of the ecological relevance of behavioral end points.

Impact of childhood and adulthood psychological health on labour force participation and exit in later life

BACKGROUND

Adulthood psychological health predicts labour force activity but few studies have examined childhood psychological health. We hypothesized that childhood psychological ill-health would be associated with labour force exit at 55 years.

METHOD

Data were from the 55-year follow-up of the National Child Development Study (n = 9137). Labour force participation and exit (unemployment, retirement, permanent sickness, homemaking/other) were self-reported at 55 years. Internalizing and externalizing problems in childhood (7, 11 and 16 years) and malaise in adulthood (23, 33, 42, 50 years) were assessed. Education, social class, periods of unemployment, partnership separations, number of children, and homemaking activity were measured throughout adulthood.

RESULTS

Childhood internalizing and externalizing problems were associated with unemployment, permanent sickness and homemaking/other at 55 years, after adjustment for adulthood psychological health and education: one or two reports of internalizing was associated with increased risk for unemployment [relative risk (RR) 1.59, 95% confidence interval (CI) 1.12-2.25; RR 2.37, 95% CI 1.48-3.79] and permanent sickness (RR 1.32, 95% CI 1.00-1.74; RR, 1.48, 95% CI 1.00-2.17); three reports of externalizing was associated with increased risk for unemployment (RR 2.26, 95% CI 1.01-5.04), permanent sickness (RR 2.63, 95% CI 1.46-4.73) and homemaking/other (RR 1.95, 95% CI 1.00-3.78).

CONCLUSIONS

Psychological ill-health across the lifecourse, including during childhood, reduces the likelihood of working in older age. Support for those with mental health problems at different life stages and for those with limited connections to the labour market, including homemakers, is an essential dimension of attempts to extend working lives.

Informal caregiving as a risk factor for type 2 diabetes in individuals with favourable and unfavourable psychosocial work environments: A longitudinal multi-cohort study

AIM

To examine whether informal caregiving is associated with increased risk of type 2 diabetes (T2D), and whether job strain and social support at work modify the association.

METHODS

Individual participant's data were pooled from three cohort studies-the French GAZEL study, the Swedish Longitudinal Occupational Survey of Health (SLOSH) and the British Whitehall II study-a total of 21,243 study subjects. Informal caregiving was defined as unpaid care for a closely related person. Job strain was assessed using the demand-control model, and questions on co-worker and supervisor support were combined in a measure of social support at work. Incident T2D was ascertained using registry-based, clinically assessed and self-reported data.

RESULTS

A total of 1058 participants developed T2D during the up to 10 years of follow-up. Neither informal caregiving (OR: 1.09, 95% CI: 0.92-1.30) nor high job strain (OR: 1.04, 95% CI: 0.86-1.26) were associated with T2D risk, whereas low social support at work was a risk factor for T2D (OR: 1.18, 95% CI: 1.02-1.37). Also, informal caregivers who were also exposed to low social support at work were at higher risk of T2D (OR: 1.40, 95% CI: 1.08-1.82) compared with those who were not informal caregivers and had high social support at work (multiplicative test for interaction, P=0.04; additive test for interaction, synergy index=10).

CONCLUSION

Informal caregiving was not independently associated with T2D risk. However, low social support at work was a risk factor, and informal caregivers with low social support at work had even higher risks of T2D.

Parental Whole Life Cycle Exposure to Dietary Methylmercury in Zebrafish (Danio rerio) Affects the Behavior of Offspring

Methylmercury (MeHg) is an established neurotoxicant of concern to fish-eating organisms. While most studies have focused on the fish consumers, much less is known about the effects of MeHg on the fish themselves, especially following exposures to chronic and environmentally relevant scenarios. Here we evaluated the behavioral effects of developmental MeHg insult by exposing parental generations of zebrafish to an environmentally realistic MeHg dietary concentration (1 ppm) and two higher concentrations (3 and 10 ppm) throughout their whole life span. Upon reaching adulthood, their offspring were analyzed through a series of behavioral tests, including the visual-motor response (VMR) assay, analysis of spontaneous swimming and evaluation of foraging efficiency. The VMR assay identified decreased locomotor output in the 6 day postfertilization (dpf) offspring of fish exposed to 3 and 10 ppm MeHg. However, in a second test 7 dpf fish revealed an increase in locomotor activity in all MeHg exposures tested. Increases in locomotion continued to be observed until 16 dpf, which coincided with increased foraging efficiency. These results suggest an association between MeHg and hyperactivity, and imply that fish chronically exposed to MeHg in the wild may be vulnerable to predation.

Serum C-reactive protein levels predict regional brain responses to noxious cold stimulation of the hand in chronic whiplash associated disorders

BACKGROUND AND AIMS

Whiplash Associated Disorders (WAD) are a costly health burden. The condition is characterised by sensory disturbances such as widespread hyperalgesia likely indicative of central hyperexcitability. Recently elevated levels of pro-inflammatory biomarkers have also found in acute and chronic WAD. The aim of this cross-sectional study was to investigate the relationship between inflammatory biomarkers and pain processing in people with persistent whiplash associated disorders (WAD).

METHODS

Twenty one participants with chronic whiplash (>3 months) were recruited. Venous blood samples were collected and assays performed for C-reactive protein (CRP) and TNF-α. Blood oxygen level-dependent (BOLD) contrast images of the brain were acquired with a Siemens 1.5T MRI scanner during repeated 24s stimulus blocks of innocuous or painful stimuli (thumbnail pressure and cold stimulation of dorsum of hand) separated by 36s inter-stimulus intervals. Stimulus intensities used during scanning were at the level of participants' thresholds for moderate pain. Parameter estimates representing BOLD signal increases during painful events from each participant were tested for associations with inflammatory biomarkers.

RESULTS

Clinically relevant levels of CRP and TNF-α were found in 33% and 38% of participants. Levels of CRP showed a positive correlation with levels of cold pain activation in brain regions including the anterior insula, posterior parietal cortex, caudate and thalamus (p_corrected<0.05). Levels of TNF-α were not related to activation levels during either noxious pressure or cold. Pressure pain activations also did not show a relationship with CRP levels.

CONCLUSIONS

Shared variance between inflammation and increased levels of regional pain-related activation in people with persistent whiplash symptoms is apparent for cold, but not pressure stimuli.

IMPLICATIONS

The results highlight cold pain processing as an important aspect of whiplash chronicity, although the implications of this modality-specific effect are not readily apparent.

Psychosocial factors associated with work disability in men and women with diabetes: a pooled analysis of three occupational cohort studies

AIMS

To examine the extent to which adverse psychosocial factors, such as living alone, psychological distress, job strain and low support from supervisor, increase the risk of work disability (sickness absence and disability pension) among employees with diabetes.

METHODS

In this pooled analysis of individual-participant data from three occupational cohort studies (the Finnish Public Sector Study, the British Whitehall II study, and the French GAZEL study), 1088 women and 949 men with diabetes were followed up to determine the duration (number of days) and frequency (number of spells) of work disability. The mean follow-up periods were 3.2 years in the GAZEL study, 4.6 years in the Whitehall II study and 4.7 years in the Finnish Public Sector Study. Psychosocial factors and potential confounding factors were assessed at baseline using standard questionnaires. Study-specific estimates were pooled using fixed-effects meta-analysis.

RESULTS

In analysis adjusted for sociodemographic factors, health behaviours and comorbidities, participants with psychological distress had longer (rate ratio 1.66; 95% CI 1.31-2.09) and more frequent absences (rate ratio 1.33; 95% CI 1.19-1.49) compared with those with no psychological distress. Job strain was associated with slightly increased absence frequency (rate ratio 1.19 95% CI 1.05-1.35), but not with absence duration. Living alone and low supervisor support were not associated with absence duration or frequency. We observed no sex differences in these associations.

CONCLUSIONS

Psychological distress was associated with increased duration and frequency of work disability among employees with diabetes. Job strain was associated with increased absence frequency but not with absence duration.

Lifestyle-related risk factors and trajectories of work disability over 5 years in employees with diabetes: findings from two prospective cohort studies

AIMS

To examine work disability trajectories among employees with and without diabetes and identify lifestyle-related factors associated with these trajectories.

METHODS

We assessed work disability using records of sickness absence and disability pension among participants with diabetes and age- sex-, socio-economic status- and marital status-matched controls in the Finnish Public Sector Study (1102 cases; 2204 controls) and the French GAZEL study (500 cases; 1000 controls), followed up for 5 years. Obesity, physical activity, smoking and alcohol consumption were assessed at baseline and the data analysed using group-based trajectory modelling.

RESULTS

Five trajectories described work disability: 'no/very low disability' (41.1% among cases and 48.0% among controls); 'low-steady' (35.4 and 34.7%, respectively); 'high-steady' (13.6 and 12.1%, respectively); and two 'high-increasing' trajectories (10.0 and 5.2%, respectively). Diabetes was associated with a 'high-increasing' trajectory only (odds ratio 1.90, 95% CI 1.47-2.46). Obesity and low physical activity were similarly associated with high work disability in people with and without diabetes. Smoking was associated with 'high-increasing' trajectory in employees with diabetes (odds ratio 1.88, 95% CI 1.21-2.93) but not in those without diabetes (odds ratio 1.32, 95% CI 0.87-2.00). Diabetes was associated with having multiple ( ≥ 2) risk factors (21.1 vs. 11.4%) but the association between multiple risk factors and the 'high-increasing' trajectory was similar in both groups.

CONCLUSIONS

The majority of employees with diabetes have low disability rates, although 10% are on a high and increasing disability trajectory. Lifestyle-related risk factors have similar associations with disability among employees with and without diabetes, except smoking which was only associated with poorer prognosis in diabetes.