Oxidative stress and DNA damage in agricultural workers after exposure to pesticides

Chlorpyrifos intermittent exposure enhances cardiovascular but not behavioural responses to contextual fear conditioning in adult rats: Possible involvement of brain oxidative-nitrosative stress

Exposure to organophosphorus compounds (OPs) may cause psychiatric, neurologic, biochemical, and cardiovascular abnormalities. Neurotoxicity of OP compounds is primarily due to irreversibly inhibition of the acetylcholinesterase (AChE) enzyme both centrally and peripherally. Chlorpyrifos (CPF) is a widely used OP classified as moderately toxic. Previously, it has been shown that CPF administration, given every other day to adult rats, impairs spatial memory and prepulse inhibition associated with brain AChE inhibition. Our group also found that intermittent treatment with CPF, simulating occupational exposure, impairs the cardiorespiratory reflexes and causes cardiac hypertrophy. Thereby, we aimed to examine whether subchronic and intermittent administration of CPF would affect the behavioural (freezing) and cardiovascular (mean arterial pressure, MAP; heart rate, HR) responses elicited during contextual fear conditioning (CFC) and extinction. Wistar adult male rats were injected with sublethal and intermittent CPF doses (4 and 7 mg/kg) three times a week for one month. Two days after the last injection, a range of tests were performed to assess depression (sucrose preference), anxiety (elevated plus-maze, EPM), locomotion (open field, OF), and conditioned fear expression and extinction. Separate cohorts of animals were euthanized to measure plasma butyrylcholinesterase (BChE), erythrocyte AChE, brain AChE activity, and markers of oxidative-nitrosative stress. Intermittent CPF treatment did not affect sucrose preference. CPF (4 and 7 mg/kg) reduced open-arms exploration in the EPM, suggesting an anxiogenic effect. The higher dose of CPF decreased the total distance travelled in the OFT, suggesting motor impairment. After a seven-day CPF-free washout period, CPF (7 mg/kg) increased the tachycardic response without affecting freezing behaviour in the CFC extinction session. CPF 7 mg/kg decreased AChE activity in the hippocampus, pre-frontal cortex and brainstem 72 after the last administration whilst transiently increasing oxidative-nitrosative stress specifically in the brainstem. Overall, our results outlined the behavioural, autonomic and biochemical abnormalities caused by an intermittent dosing regimen of CPF that elicits brain AChE inhibition and brain oxidative-nitrosative stress. This paradigm might be valuable in further exploring long-term consequences and mechanisms of OP neurotoxicity as well as comprehensive therapeutic approaches.

Patho-physiological effects of environmental relevant concentrations of lufenuron in male Japanese quails

The widespread utilization of synthetic chemicals contaminates the land and water environments. The present investigation determined the effects of sub-lethal concentrations of lufenuron in the male Japanese quail. The birds exposed to lufenuron showed the clinical signs of behavioral, digestive, nervous and reproductive upsets. The drug significantly (p<0.05) decreased the feed intake, body weight, absolute and relative weights of visceral organs (kidneys, liver, brain, heart, testes), RBCs count, HCT, Hg concentration, serum proteins and anti-oxidants enzymes (SOD, CAT, LPO, GSH) while concentrations of hepatic, cardiac and renal biomarkers were significantly (p<0.05) increased in the birds treated with higher doses (15mg/kg and 20mg/kg) of lufenuron, in a time and dose dependent manner. Comet assay revealed significantly (p<0.05) increased frequency of DNA damage in the isolated cells of liver, kidneys and intestine along with a significant (p<0.05) increased frequency of micronucleus in the erythrocytes. The visceral organs showed prominent histo-pathological ailments in the birds exposed to higher doses of lufenuron. Our study is the first comprehensive report that demonstrates the significant physio-biochemical health effects of lufenuron on complete clinico-hematological parameters of free ranging fauna (quail) of the natural ecosystem, even at sub-lethal environment relevant concentrations.

Environmental exposure to lead and cadmium only minimally affects the redox system of the follicular fluid and the outcome of intracytoplasmic sperm injection

The purpose of our study was to determine the influence of lead and cadmium in concentrations commonly found in the environment on the redox system of the follicular fluid (FF) and on the results of assisted reproduction. A prospective study of 113 patients with unexplained infertility who qualified for intracytoplasmic sperm injection (ICSI). Patients with moderate or severe endometriosis or poor ovarian reserve were excluded from the study. Biochemical analyses and heavy metal assays of follicular fluid and serum (blood) were followed by statistical analyses of dependencies between lead and cadmium and the components of redox system and results of assisted reproduction. A highly significant linear correlation of lead (Pb) and cadmium (Cd) concentrations in serum and in FF was stated. The number of retrieved oocytes and MII (metaphase II stage) oocytes depended on the malondialdehyde (MDA), catalase (CAT), catalase/g of protein (CAT/g of protein), and glutathione reductase (GR) concentrations. Among biochemical factors, MDA was the only factor that correlated negatively with cadmium concentration in serum and FF and simultaneously influenced the number of retrieved oocytes and MII oocytes. The fertilization rate of MII oocytes was influenced by thiol groups-SH, SH/g of protein, CAT, CAT/g of protein, and glutathione peroxidase/g of protein (GPx/g of protein). The Pb and Cd concentrations in FF did not significantly influence the fertilization rates. Lead as well as cadmium at concentrations commonly found in women of reproductive age despite some adaptive changes in the redox system in follicular fluid do not cause large changes in the ovarian follicular environment as a whole and do not significantly worsen the final results of assisted reproduction.

Detoxification of paraoxon-ethyl by Lysiphyllum strychnifolium extracts in undifferentiated human neuroblastoma SH-SY5Y cells

CONTEXT

Lysiphyllum strychnifolium (Craib) A. Schmitz. (Fabaceae) is a Thai traditional medicine used to remove food and alcohol toxins from the body.

OBJECTIVE

This study investigates the molecular mechanism of L. strychnifolium extracts against paraoxon-ethyl-induced apoptosis in SH-SY5Y cells.

MATERIALS AND METHODS

The ethanol and water extracts of leaves and stems of L. strychnifolium were prepared at various concentrations (0-100 μg/mL) and co-treated to the cells with 0.375 mM paraoxon-ethyl for 24 and 48 h. Cell viability was performed using the PrestoBlue assay. ROS and caspase activity were detected using 2',7'-dichlorodihydrofluorecein diacetate and caspase-Glo® 3/7, 8, and 9 assay kits. Apoptotic and ER stress-related gene expression were determined by real-time PCR, and nuclear and mitochondrial morphology were observed using Hoechst 33342 and MitoTracker® Deep Red FM staining.

RESULTS

The most effective concentrations of each extract against paraoxon-ethyl-induced cell death were 25 μg/mL of leaf ethanol, 12.5 μg/mL of stem ethanol, 100 μg/mL of leaf water, and 25 μg/mL of stem water extracts. The leaf ethanol extract was the most effective at detoxifying, while stem extracts were highly toxic in high doses. The detoxifying L. strychnifolium extracts against paraoxon-ethyl-induced oxidative stress decreased p53, BiP/GRP78, and CHOP gene expression and minimized caspase 9 and caspase 3, protecting cells from apoptosis. The extracts could also restore mitochondrial membrane potential and reduce the swollen globule mitochondrial shape.

DISCUSSION AND CONCLUSION

These findings could potentially protect neuron cells from neurodegenerative issues due to oxidative damage, apoptosis, and other potential consequences.

Mechanisms of Neurotoxicity of Organophosphate Pesticides and Their Relation to Neurological Disorders

Organophosphates (OPs) refers to a diverse group of phosphorus-containing organic compounds; they are widely used all over the world and have had an important beneficial impact on industrial and agricultural production and control of vector transmission. Exposure to OPs of different toxicities (high, moderate, slight, and low toxicity) can all have negative consequences on the nervous system, such as nausea, vomiting, muscle tremors, and convulsions. In severe cases, it can lead to respiratory failure or even death. Notably, OPs induce neuropathy in the nervous system through specific interactions with nicotinic or muscarinic receptors, phosphorylating acetylcholinesterase, or neuropathic target esterases. This review summarizes the possible toxicological mechanisms and their interplay underlying OP pesticide poisoning, including cholinesterase inhibition and non-cholinesterase mechanisms. It outlines the possible links between OP pesticide poisoning and neurological disorders, such as dementia, neurodevelopmental diseases, and Parkinson's disease. Additionally, it explores OP interactions' potential therapeutic implications that may help mitigate the deleterious impact of OPs on the nervous system.

Analysis of mitochondrial DNA copy number variation in Brazilian farmers occupationally exposed to pesticides

The use of pesticide use has been linked to the higher production of reactive oxygen species, resulting in oxidative stress, which in turn can cause genomic instability. A marker for instability is the copy number variation of the mitochondrial genome (mtDNAcn), which has been found to be altered in diverse human diseases, including tumors. This research aimed to examine the variation of mtDNAcn in individuals occupationally exposed to pesticides. Real-time PCR assays were conducted on 154 individuals (78 exposed and 76 non-exposed). Pesticide-exposed ndividuals exhibited a significant reduction in mtDNAcn (1.11 ± 0.37mtDNAcn/genome) compared to non-exposed individuals (1.30 ± 0.33mtDNAcn/genome; p = 0.001). The multivariate analysis indicated that individuals who reported using haloxyfop and copper sulfate demonstrated an increase (β = 0.200, p = 0.053) and a decrease (β=-0.2, p = 0.021), respectively, in mtDNAcn. In conclusion, our findings suggest that chronic exposure to pesticides results in changes in mtDNAcn.

Biomonitoring urinary pesticide metabolites in preschool children by supported liquid extraction and ultra-high performance liquid chromatography-tandem mass spectrometry and their association with oxidative stress

Investigating pesticide exposure and oxidative stress in preschool children is essential for elucidating the determinants of environmental health in early life, with human biomonitoring of urinary pesticide metabolites serving as a critical strategy for achieving this objective. This study demonstrated biomonitoring of 2 phenoxyacetic acid herbicides, 2 organophosphorus pesticide metabolites, and 4 pyrethroid pesticide metabolites in 159 preschool children and evaluated their association with oxidative stress biomarker 8-hydroxydeoxyguanosine. An enzymatic deconjugation process was used to release urinary pesticide metabolites, which were then extracted and enriched by supported liquid extraction, and quantified by ultra-high performance liquid chromatography-tandem mass spectrometry with internal standard calibration. Dichloromethane: methyl tert‑butyl ether (1:1, v/v) was optimized as the solvent for supported liquid extraction, and we validated the method for linear range, recovery, matrix effect and method detection limit. Method detection limit of the pesticide metabolites ranged from 0.01 μg/L to 0.04 μg/L, with satisfactory recoveries ranging from 70.5 % to 95.5 %. 2,4,5-Trichlorophenoxyacetic acid was not detected, whereas the other seven pesticide metabolites were detected with frequencies ranging from 10.1 % to 100 %. The concentration of urinary pesticide metabolites did not significantly differ between boys and girls, with the median concentrations being 9.39 μg/L for boys and 4.90 μg/L for girls, respectively. Spearman correlation analysis indicated that significant positive correlations among urinary metabolites. Bayesian kernel machine regression revealed a significant positive association between urinary pesticide metabolites and 8-hydroxydeoxyguanosine. Para-nitrophenol was the pesticide metabolite that contributed significantly to the elevated level of oxidative stress.

DNA modifications: Biomarkers for the exposome?

The concept of the exposome is the encompassing of all the environmental exposures, both exogenous and endogenous, across the life course. Many, if not all, of these exposures can result in the generation of reactive species, and/or the modulation of cellular processes, that can lead to a breadth of modifications of DNA, the nature of which may be used to infer their origin. Because of their role in cell function, such modifications have been associated with various major human diseases, including cancer, and so their assessment is crucial. Historically, most methods have been able to only measure one or a few DNA modifications at a time, limiting the information available. With the development of DNA adductomics, which aims to determine the totality of DNA modifications, a far more comprehensive picture of the DNA adduct burden can be gained. Importantly, DNA adductomics can facilitate a "top-down" investigative approach whereby patterns of adducts may be used to trace and identify the originating exposure source. This, together with other 'omic approaches, represents a major tool for unraveling the complexities of the exposome and hence allow a better a understanding of the environmental origins of disease.

Polymorphisms in ERCC1, ERCC4 and ERCC5 genes as biomarkers of susceptibility for pesticide-induced DNA damage in North-West Indian agricultural workers

BACKGROUND

Occupational pesticides exposure has raised health concerns due to genotoxicity and accumulation of DNA damage. Polymorphisms in genes encoding enzymes involved in nucleotide excision repair (NER) may affect the individual's susceptibility to pesticide toxicity.

METHODS

This study evaluates the association of excision repair cross complementation group 1 (ERCC1) (8092 C > A, 3'UTR, rs3212986) and ERCC1 (19007 C > T, Asn118Asn, rs11615), ERCC4 (1244 G > A, Arg415Gln, rs1800067) and ERCC5 (3507 G > C, Asp1104His, rs17655) polymorphisms with pesticide-induced DNA damage in North-West Indian agricultural workers. The study population comprised 225 agricultural workers exposed to pesticides and 225 non-exposed controls.

RESULTS

Our study demonstrate that exposed workers carrying variant ERCC1 8092AA genotype showed higher total comet DNA migration (p = 0.015) as well as increased frequency of cells showing DNA migration (p = 0.027). Exposed agricultural workers with variant ERCC4 1244AA (415Gln/Gln) and ERCC5 3507CC (1104His/His) genotypes exhibited elevation in total comet DNA migration (p < 0.01). However, genotypes of ERCC1 19007 C > T (Asn118Asn) showed no association with total comet DNA migration (p = 0.963), frequency of cells showing DNA migration (p = 0.423) as well as mean tail length (p = 0.432).

CONCLUSION

ERCC1, ERCC4 and ERCC5 polymorphisms influence DNA damage and can be used as biomarkers of susceptibility for pesticide-induced DNA damage in North-West Indian agricultural workers.

Association of occupational exposure to pesticides with overweight in farmers in Southern Brazil

INTRODUCTION

Exposure to pesticides may be related to overweight and associated comorbidities. The aim of this work was to evaluate occupational exposure to pesticides, overweight and associated comorbidities among farmers in Southern Brazil.

METHODS

This cross-sectional study included a random sample of 257 farmers, living in the municipality of Mafra and Planalto, southern Brazil. Data on pesticide use and overweight prevalence from farmers were collected using an in-person interview questionnaire, followed by blood collection and biochemical analyses.

RESULTS

Pesticide exposure was positively correlated with body mass index, waist circumference, waist-to-hip ratio, triglycerides and glucose levels, presence of hypertension and metabolic syndrome. Besides that, the fact of being exposed to pesticides represents a decrease of no protein thiol groups. Furthermore, the main pesticides used by farmers have hepatic toxicity.

CONCLUSION

These findings suggest that exposure to pesticides may be associated with overweight and associated comorbidities. Further studies are required to validate our findings and elucidate the specific mechanisms by which these pollutants contribute to the development of overweight.

Endocrine disrupting chemicals and male fertility: from physiological to molecular effects

The deleterious effects of chemical or non-chemical endocrine disruptors (EDs) on male fertility potential is well documented but still not fully elucidated. For example, the detection of industrial chemicals' metabolites in seminal plasma and follicular fluid can affect efficiency of the gametogenesis, the maturation and competency of gametes and has guided scientists to hypothesize that endocrine disrupting chemicals (EDCs) may disrupt hormonal homoeostasis by leading to a wide range of hormonal control impairments. The effects of EDCs exposure on reproductive health are highly dependent on factors including the type of EDCs, the duration of exposure, individual susceptibility, and the presence of other co-factors. Research and scientists continue to study these complex interactions. The aim of this review is to summarize the literature to better understand the potential reproductive health risks of EDCs in France.

Unraveling the Gut-Brain Axis in Multiple Sclerosis: Exploring Dysbiosis, Oxidative Stress, and Therapeutic Insights

This comprehensive review delves into the intricate relationship between the gut microbiota and multiple sclerosis (MS), shedding light on the potential therapeutic avenues for this complex autoimmune disease. It emphasizes the multifactorial nature of MS, including genetic, environmental, and gender-related factors. Furthermore, the article highlights the emerging role of gut microbiota in MS pathophysiology, particularly in terms of gut dysbiosis, oxidative stress, and inflammasome activation within the gut-brain axis. This interplay raises intriguing questions about how the gut microbiota influences the onset and progression of MS. Environmental factors, such as diet and pollutants, add further layers of complexity to the connection between gut health and MS risk. This review also discusses promising therapeutic interventions, such as fecal microbiota transplantation, probiotics, dietary adjustments, and gut-derived metabolites that offer potential avenues for managing MS. It underscores the need for ongoing research to fully unravel the complexities of the role of the gut-brain axis in MS. Ultimately, this article provides a comprehensive exploration of the topic, offering hope for novel preventive and therapeutic strategies that could significantly improve the lives of individuals affected by this challenging autoimmune condition.

Unmasking the Hidden Danger: A Decade-Long Systematic Review of Case-Control Studies on Single Occupational Risks and Prostate Cancer

The present systematic review addresses the influence of occupational exposures on prostate cancer risk. Eleven studies were analyzed for a range of occupational exposures, including but not limited to firefighting, physical activity, night shift work, chemical exposure, and solar ultraviolet radiation. The results of the review reveal that firefighters exposed to harmful substances, individuals engaged in physically strenuous work, and workers with chronic night shift routines showed an increased likelihood of developing prostate cancer. Moreover, the review identified an increased risk associated with exposure to certain chemicals, including alkylphenolic compounds and benzene-related substances. The evidence underscores the importance of considering the cumulative effect of multiple risk factors in a comprehensive risk assessment. However, the conclusions indicate the necessity for further research to deepen these relationships and develop more effective strategies for the prevention of prostate cancer.

The Hematological and Biochemical Effects from Pesticide Exposure on Thai Vegetable Farmers

Pesticide-related health concerns are a global public health issue. Few studies in Thailand have explored the hematological and biochemical effects of occupational pesticide exposure. The goal of this study was to investigate the effects of pesticides on the hematology, hepatic, and renal function of Thai vegetable farmers. A cross-sectional study was carried out in Chiang Mai, northern Thailand. A total of 124 apparently healthy vegetable farmers were interviewed about their lifetime exposure to agricultural pesticides. Blood samples were collected via venipuncture to be tested for complete blood count (CBC), liver function, and kidney function. Approximately 46% of the farmers were pesticide users who reported a history of pesticide use for their crops, while 54% were non-pesticide users. In the male farmers, the activities of aspartate aminotransferase (AST), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) were significantly higher in the pesticide users compared to the non-pesticide users, while the estimated glomerular filtration rate (eGFR), hematocrit (HCT), and red blood cells (RBC) were significantly lower (p < 0.05). In the females, the pesticide users had significantly higher levels of alanine aminotransferase (ALT), alkaline phosphatase (ALP), and MCHC than the non-pesticide users (p < 0.05). Pesticide use among Thai vegetable farmers may cause hematological alterations and increase the risk of hepatic and renal dysfunction. Some hematological and biochemical parameters may be used for monitoring to protect them from the adverse health effects of occupational exposure to pesticides.

Development and Validation of a New UFLC-MS/MS Method for the Detection of Organophosphate Pesticide Metabolites in Urine

To monitor human exposure to pesticides, experts commonly measure their metabolites in urine, particularly dialkyl phosphates (DAPs), which include diethyl phosphate (DEP), Diethyl thiophosphate (DETP), diethyl dithiophosphate (DEDTP), dimethyl phosphate (DMP), dimethyl thiophosphate (DMTP) and dimethyl dithiophosphate (DMDTP)to monitor the metabolites of organophosphates. These DAP metabolites are a urinary biomarker for assessing pesticide exposure and potential health risks. This study presented a new screening method combining ultrafast liquid chromatography with tandem mass spectrometry (UFLC-MS/MS) to detect six DAP metabolites in human urine. The study also compared standard sample extraction methods, namely, liquid-liquid extraction (LLE); quick, easy, cheap, effective, ruggedand safe (QuEChERS); and lyophilization. After a comprehensive analysis of the methods used to extract the analytes, including recovery rate, repeatability and reproducibility, the liquid-liquid extraction (LLE) method was found to be the best. It had a high recovery rate, was easy to handle, required less sample volume and had a short extraction time. Therefore, the LLE method was chosen for further analysis. The results showed excellent performance with high recoveries between 93% and 102%, precise repeatability (RSD) between 0.62% and 5.46% and acceptable reproducibility values (RSD) between 0.80% and 11.33%. The method also had limits of detection (LOD) ranging from 0.0201 ng/mL to 0.0697 ng/mL and limits of quantification (LOQ) ranging from 0.0609 ng/mL to 0.2112 ng/mL. Furthermore, the UFLC-MS/MS method was validated based on the SANTE guidance and successfully analyzed 150 urine samples from farmers and non-farmers. This validated method proved useful for biomonitoring studies focusing on OP pesticide exposure. It offers several advantages, such as a reduced need for samples, chemicals and materials, and a shorter analysis time. The method is sensitive and selective in detecting metabolites in human urine, making it a valuable approach for the practical and efficient assessment of pesticide exposure.

The Gut-Brain Axis as a Therapeutic Target in Multiple Sclerosis

The CNS is very susceptible to oxidative stress; the gut microbiota plays an important role as a trigger of oxidative damage that promotes mitochondrial dysfunction, neuroinflammation, and neurodegeneration. In the current review, we discuss recent findings on oxidative-stress-related inflammation mediated by the gut-brain axis in multiple sclerosis (MS). Growing evidence suggests targeting gut microbiota can be a promising strategy for MS management. Intricate interaction between multiple factors leads to increased intra- and inter-individual heterogeneity, frequently painting a different picture in vivo from that obtained under controlled conditions. Following an evidence-based approach, all proposed interventions should be validated in clinical trials with cohorts large enough to reach significance. Our review summarizes existing clinical trials focused on identifying suitable interventions, the suitable combinations, and appropriate timings to target microbiota-related oxidative stress. Most studies assessed relapsing-remitting MS (RRMS); only a few studies with very limited cohorts were carried out in other MS stages (e.g., secondary progressive MS-SPMS). Future trials must consider an extended time frame, perhaps starting with the perinatal period and lasting until the young adult period, aiming to capture as many complex intersystem interactions as possible.

The impact of COVID-19 on maritime pilots: Evidence and lessons

The COVID-19 pandemic led to port congestion and disruption to global logistics and supply chains. While previous research has examined the impact on port performance and economics, social issues, such as the impact on port personnel (including pilots), have been overlooked. In this context, this paper examines the challenges experienced by Chinese pilots during the pandemic through in-depth interviews with 28 pilots. It shows that the draconian pandemic control measures adopted in China, rather than the pandemic itself, impaired pilots' physical and mental health, reduced their availability, and introduced new safety hazards, which curtailed both the port's capacity and ability to provide efficient and safe pilotage and resulted in sub-standard services. The findings suggest that there is a serious issue regarding the absence of effective mechanisms for pilots to raise their health and safety concerns and how these might be addressed by port administrators and/or local authorities. Worker participation and involvement in occupational health and safety management was problematic. These findings have implications for pilot station management at both company and government administrative and legislative levels.

Free Radicals and Obesity-Related Chronic Inflammation Contrasted by Antioxidants: A New Perspective in Coronary Artery Disease

We are surrounded by factors called free radicals (FR), which attach to the molecules our body is made of, first among them the endothelium. Even though FR are to a certain extent a normal factor, nowadays we face an escalating increase in these biologically aggressive molecules. The escalating formation of FR is linked to the increased usage of man-made chemicals for personal care (toothpaste, shampoo, bubble bath, etc.), domestic laundry and dish-washer detergents, and also an ever wider usage of drugs (both prescription and over the counter), especially if they are to be used long-term (years). In addition, tobacco smoking, processed foods, pesticides, various chronic infectious microbes, nutritional deficiencies, lack of sun exposure, and, finally, with a markedly increasing impact, electromagnetic pollution (a terribly destructive factor), can increase the risk of cancer, as well as endothelial dysfunction, owing to the increased production of FR that they cause. All these factors create endothelial damage, but the organism may be able to repair such damage thanks to the intervention of the immune system supported by antioxidants. However, one other factor can perpetuate the state of inflammation, namely obesity and metabolic syndrome with associated hyperinsulinemia. In this review, the role of FR, with a special emphasis on their origin, and of antioxidants, is explored from the perspective of their role in causing atherosclerosis, in particular at the coronary level.

Ethnic inequalities in COVID-19 infection, hospitalisation, intensive care admission, and death: a global systematic review and meta-analysis of over 200 million study participants

Background

COVID-19 has exacerbated existing ethnic inequalities in health. Little is known about whether inequalities in severe disease and deaths, observed globally among minoritised ethnic groups, relates to greater infection risk, poorer prognosis, or both. We analysed global data on COVID-19 clinical outcomes examining inequalities between people from minoritised ethnic groups compared to the ethnic majority group.

Methods

Databases (MEDLINE, EMBASE, EMCARE, CINAHL, Cochrane Library) were searched from 1st December 2019 to 3rd October 2022, for studies reporting original clinical data for COVID-19 outcomes disaggregated by ethnicity: infection, hospitalisation, intensive care unit (ICU) admission, and mortality. We assessed inequalities in incidence and prognosis using random-effects meta-analyses, with Grading of Recommendations Assessment, Development, and Evaluation (GRADE) use to assess certainty of findings. Meta-regressions explored the impact of region and time-frame (vaccine roll-out) on heterogeneity. PROSPERO: CRD42021284981.

Findings

77 studies comprising over 200,000,000 participants were included. Compared with White majority populations, we observed an increased risk of testing positive for infection for people from Black (adjusted Risk Ratio [aRR]:1.78, 95% CI:1.59-1.99, I2 = 99.1), South Asian (aRR:3.00, 95% CI:1.59-5.66, I2 = 99.1), Mixed (aRR:1.64, 95% CI:1.02-1.67, I2 = 93.2) and Other ethnic groups (aRR:1.36, 95% CI:1.01-1.82, I2 = 85.6). Black, Hispanic, and South Asian people were more likely to be seropositive. Among population-based studies, Black and Hispanic ethnic groups and Indigenous peoples had an increased risk of hospitalisation; Black, Hispanic, South Asian, East Asian and Mixed ethnic groups and Indigenous peoples had an increased risk of ICU admission. Mortality risk was increased for Hispanic, Mixed, and Indigenous groups. Smaller differences were seen for prognosis following infection. Following hospitalisation, South Asian, East Asian, Black and Mixed ethnic groups had an increased risk of ICU admission, and mortality risk was greater in Mixed ethnic groups. Certainty of evidence ranged from very low to moderate.

Interpretation

Our study suggests that systematic ethnic inequalities in COVID-19 health outcomes exist, with large differences in exposure risk and some differences in prognosis following hospitalisation. Response and recovery interventions must focus on tackling drivers of ethnic inequalities which increase exposure risk and vulnerabilities to severe disease, including structural racism and racial discrimination.

Funding

ESRC:ES/W000849/1.

Rehabilitation of Neuropsychiatric Symptoms in Patients With Long COVID: Position Statement

Long COVID, a term used to describe ongoing symptoms after COVID-19 infection, parallels the course of other postviral syndromes. Neuropsychiatric symptoms of long COVID can be persistent and interfere with quality of life and functioning. Within the biopsychosocial framework of chronic illness, rehabilitation professionals can address the neuropsychiatric sequelae of long COVID. However, current practice models are not designed to address concurrent psychiatric and cognitive symptoms in adults living with long COVID. Thus, we present a biopsychosocial framework for long COVID and provide treatment strategies based on evidence from current literature of postviral chronic illness. These recommendations will guide rehabilitation professionals in identifying common neuropsychiatric symptoms in long COVID that can be targeted for intervention and addressing these symptoms via integrative interventions taking into account the biopsychosocial presentation of long COVID symptoms.

Metabolome-wide association study of the relationship between chlorpyrifos exposure and first trimester serum metabolite levels in pregnant Thai farmworkers

INTRODUCTION

Organophosphate (OP) insecticides, including chlorpyrifos, have been linked with numerous harmful health effects on maternal and child health. Limited data are available on the biological mechanisms and endogenous pathways underlying the toxicity of chlorpyrifos exposures on pregnancy and birth outcomes. In this study, we measured a urinary chlorpyrifos metabolite and used high-resolution metabolomics (HRM) to identify biological perturbations associated with chlorpyrifos exposure among pregnant women in Thailand, who are disparately exposed to high levels of OP insecticides.

METHODS

This study included 50 participants from the Study of Asian Women and their Offspring's Development and Environmental Exposures (SAWASDEE). We used liquid chromatography-high resolution mass spectrometry to conduct metabolic profiling on first trimester serum samples collected from participants to evaluate metabolic perturbations in relation to chlorpyrifos exposures. We measured 3,5,6-trichloro-2-pyridinol (TCPy), a specific metabolite of chlorpyrifos and chlorpyrifos-methyl, in first trimester urine samples to assess the levels of exposures. Following an untargeted metabolome-wide association study workflow, we used generalized linear models, pathway enrichment analyses, and chemical annotation to identify significant metabolites and pathways associated with urinary TCPy levels.

RESULTS

In the 50 SAWASDEE participants, the median urinary TCPy level was 4.36 μg TCPy/g creatinine. In total, 691 unique metabolic features were found significantly associated with TCPy levels (p < 0.05) after controlling for confounding factors. Pathway analysis of metabolic features associated with TCPy indicated perturbations in 24 metabolic pathways, most closely linked to the production of reactive oxygen species and cellular damage. These pathways include tryptophan metabolism, fatty acid oxidation and peroxisome metabolism, cytochromes P450 metabolism, glutathione metabolism, and vitamin B3 metabolism. We confirmed the chemical identities of 25 metabolites associated with TCPy levels, including glutathione, cystine, arachidic acid, itaconate, and nicotinamide adenine dinucleotide.

DISCUSSION

The metabolic perturbations associated with TCPy levels were related to oxidative stress, cellular damage and repair, and systemic inflammation, which could ultimately contribute to health outcomes, including neurodevelopmental deficits in the child. These findings support the future development of sensitive biomarkers to investigate the metabolic underpinnings related to pesticide exposure during pregnancy and to understand its link to adverse outcomes in children.

Possible mechanisms involved in the testicular-protective property of quercetin in rats exposed to endosulfan toxicity

The study investigated the effects of quercetin and putative mechanisms involved against endosulfan-testicular impairments in rats. Rats were allotted into five treatment groups (n = 5). Groups 1-2 had normal saline and maize oil (vehicle) (10 mL/kg), group 3 received quercetin (20 mg/kg), 4-5 had endosulfan (5 mg/kg, p.o) orally for 28 days. However, from days 14-28, group 4 received an additional dose of vehicle (10 mL/kg, p.o./day), while group 5 received quercetin (20 mg/kg, p.o./day). Thereafter, blood samples and testes were harvested for markers of cholinergic, hormonal and testicular oxido-nitrergic, inflammatory, apoptosis and proton pump ATPase activities. Also, testicular histopathological changes were also evaluated alongside with germ cell count, testicular injury and spermatogenesis score. Quercetin increased testicular/body weights and spermatogenesis, androgenic hormones (follicle stimulating hormones, FSH; luteinizing hormone, LH; testosterone), acetylcholinesterase levels and attenuated altered membrane integrity, DNA fragmentation, increased caspases-3 levels in rats exposed to endosulfan. Moreover, quercetin increased testicular B-cell lymphoma-2 (Bcl-2), Bcl-2 associated x-protein (Bax) and proton pump adenosine trisphosphate (ATPase) and sialic acid levels. Of note, quercetin reversed endosulfan-mediated increased malondialdehyde, nitrite, peroxynitrite formation, 8-hydroxy-2'-deoxyguanosine and lowered antioxidant enzymes in the testes. The increased levels of testicular myeloperoxidase (MPO), tumor necrosis factor-alpha (TNF-α) and interleukin-1beta (IL-1β) by endosulfan were also reduced by quercetin administration. Additionally, quercetin attenuate endosulfan-induced testicular histopathological changes of rats. Our findings showed that quercetin significantly inhibited endosulfan-induced testicular damage and altered spermatogenesis through inhibition of oxido-nitrergic pathway, inflammatory mediators, apoptosis, acetylcholinesterase activity and enhancement of testicular hormones and improvement in testicular ATPase activity.

Toxicological Findings of Self-Poisoning Suicidal Deaths: A Systematic Review by Countries

The use of illicit and non-illicit substances is widespread in suicides. The toxicological data may help in understanding the mechanism of death. This systematic review aimed to analyze autopsies related to suicides by consuming poison, focusing on the correlation between substance use and the country of origin to create an alarm bell to indicate that suicide maybe attempted and prevent it. The systematic review was conducted according to the PRISMA guidelines, with the primary objective of identifying autopsies conducted in cases of suicide by consuming poison in specific geographic areas. Significant differences in substances were observed between low-income and Western countries that confirm previous literature data. In rural areas and Asian countries, most suicides by consuming poison involve the use of pesticides, such as organophosphates and carbamates. In Western countries, illicit drugs and medically prescribed drugs are the leading cause of suicide by self-poisoning. Future research should shed light on the correlation between social, medical, and demographic characteristics and the autopsy findings in suicides by self-poisoning to highlight the risk factors and implement tailored prevention programs worldwide. Performing a complete autopsy on a suspected suicide by self-poisoning could be essential in supporting worldwide public health measures and policy makers. Therefore, complete autopsies in such cases must be vigorously promoted.

Human Exposure to Pesticides in Dust from Two Agricultural Sites in South Africa

Over the last decades, concern has arisen worldwide about the negative impacts of pesticides on the environment and human health. Exposure via dust ingestion is important for many chemicals but poorly characterized for pesticides, particularly in Africa. We investigated the spatial and temporal variations of 30 pesticides in dust and estimated the human exposure via dust ingestion, which was compared to inhalation and soil ingestion. Indoor dust samples were collected from thirty-eight households and two schools located in two agricultural regions in South Africa and were analyzed using high-performance liquid chromatography coupled to tandem mass spectrometry. We found 10 pesticides in dust, with chlorpyrifos, terbuthylazine, carbaryl, diazinon, carbendazim, and tebuconazole quantified in >50% of the samples. Over seven days, no significant temporal variations in the dust levels of individual pesticides were found. Significant spatial variations were observed for some pesticides, highlighting the importance of proximity to agricultural fields or of indoor pesticide use. For five out of the nineteen pesticides quantified in dust, air, or soil (i.e., carbendazim, chlorpyrifos, diazinon, diuron and propiconazole), human intake via dust ingestion was important (>10%) compared to inhalation or soil ingestion. Dust ingestion should therefore be considered in future human exposure assessment to pesticides.

Pesticide Pollution: Detrimental Outcomes and Possible Mechanisms of Fish Exposure to Common Organophosphates and Triazines

Pesticides are well known for their high levels of persistence and ubiquity in the environment, and because of their capacity to bioaccumulate and disrupt the food chain, they pose a risk to animals and humans. With a focus on organophosphate and triazine pesticides, the present review aims to describe the current state of knowledge regarding spatial distribution, bioaccumulation, and mode of action of frequently used pesticides. We discuss the processes by which pesticides and their active residues are accumulated and bioconcentrated in fish, as well as the toxic mechanisms involved, including biological redox activity, immunotoxicity, neuroendocrine disorders, and cytotoxicity, which is manifested in oxidative stress, lysosomal and mitochondrial damage, inflammation, and apoptosis/autophagy. We also explore potential research strategies to close the gaps in our understanding of the toxicity and environmental risk assessment of organophosphate and triazine pesticides.

The work-life balance of general practitioners as a predictor of burnout and motivation to stay in the profession

Background

Work-life balance (WLB) is associated with a variety of health-related outcomes in the general population. Since General Practitioners (GPs) play a fundamental role in the health system, we wanted to analyze the associations between their WLB and burnout scores as well as motivation to stay in the profession.

Methods

In September 2019, physicians from various specialties answered a comprehensive questionnaire. We analyzed a subsample of 188 GPs that were working full time, 61.7% were female.

Results

Multivariate analysis showed a beneficial association between WLB and all three dimensions of burnout (Emotional Exhaustion, Cynicism, and Professional Efficacy) as well as the motivation to stay in the profession.

Conclusions

Improving GPs WLB could be a way to reduce physician burnout, strengthen the healthcare system, and attract a new generation of talented physicians.

Long-Term COVID: Case Report and Methodological Proposals for Return to Work

Almost two years after the beginning of the SARS-CoV-2 pandemic, the knowledge of which in the infectious and therapeutic spheres is constantly evolving, attention paid to the medicolegal aspects linked to this emergency phenomenon has mainly focused on the liability implications falling on healthcare personnel. With regard to the medicolegal assessment of the outcomes of COVID-19 illness, although it is a procedure that is commonly used, and although references in the assessment tables in force have been adhered to, a specific assessment protocol has not been standardized that takes into account, from an objective point of view, the degree of severity of the long-term residual outcomes and their impact on the social and working lives of subjects. This shortcoming appears to be attributable to the immediate need to categorize the results of COVID-19, but, in our opinion, it deserves an in-depth study and protocols to enable evaluation committees to draw up an assessment as precisely as possible and that is free of gaps, which could be the subject of legal disputes. The aim of the present work, in light of a worldwide problem, is to arrive at specific and univocal evaluation criteria for COVID-19 disease outcomes, applicable in different operational contexts of reemployment.

Molecular Physicochemical Properties of Selected Pesticides as Predictive Factors for Oxidative Stress and Apoptosis-Dependent Cell Death in Caco-2 and HepG2 Cells

In this work, three pesticides of different physicochemical properties: glyphosate (GLY, herbicide), imidacloprid (IMD, insecticide), and imazalil (IMZ, fungicide), were selected to assess their cytotoxicity against Caco-2 and HepG2 cells. Cell viability was assessed by the Alamar Blue assay, after 24 and 48 h exposure to different concentrations, and IC50 values were calculated. The mechanisms underlying toxicity, namely cellular reactive oxygen species (ROS), glutathione (GSH) content, lipid peroxidation, loss of mitochondrial membrane potential (MMP), and apoptosis/necrosis induction were assessed by flow cytometry. Cytotoxic profiles were further correlated with the molecular physicochemical parameters of pesticides, namely: water solubility, partition coefficient in an n-octanol/water (Log Pow) system, topological polar surface area (TPSA), the number of hydrogen-bonds (donor/acceptor), and rotatable bonds. In vitro outputs resulted in the following toxicity level: IMZ (Caco-2: IC50 = 253.5 ± 3.37 μM, and HepG2: IC50 = 94 ± 12 μM) > IMD (Caco-2: IC50 > 1 mM and HepG2: IC50 = 624 ± 24 μM) > GLY (IC50 >>1 mM, both cell lines), after 24 h treatment, being toxicity time-dependent (lower IC50 values at 48 h). Toxicity is explained by oxidative stress, as IMZ induced a higher intracellular ROS increase and lipid peroxidation, followed by IMD, while GLY did not change these markers. However, the three pesticides induced loss of MMP in HepG2 cells while in Caco-2 cells only IMZ produced significant MMP loss. Increased ROS and loss of MMP promoted apoptosis in Caco-2 cells subjected to IMZ, and in HepG2 cells exposed to IMD and IMZ, as assessed by Annexin-V/PI. The toxicity profile of pesticides is directly correlated with their Log Pow, as affinity for the lipophilic environment favours interaction with cell membranes governs, and is inversely correlated with their TPSA; however, membrane permeation is favoured by lower TPSA. IMZ presents the best molecular properties for membrane interaction and cell permeation, i.e., higher Log Pow, lower TPSA and lower hydrogen-bond (H-bond) donor/acceptor correlating with its higher toxicity. In conclusion, molecular physicochemical factors such as Log Pow, TPSA, and H-bond are likely to be directly correlated with pesticide-induced toxicity, thus they are key factors to potentially predict the toxicity of other compounds.

Variability in urinary concentrations of primary aromatic amines

Despite their known carcinogenic potential, primary aromatic amines (AAs) continue to be used in various consumer products. Human exposure to AAs is a subject of current concern. Although urinary measurements are used in the assessment of exposure, little is known about within- and between-individual temporal variability in urinary concentrations of AAs. In this study, we determined the concentrations of 30 AAs, nicotine and cotinine in 213 first morning void (FMV) urine samples collected longitudinally for over a five-week period from 15 participants residing in the Albany area of New York State, USA. Eight AAs, namely, aniline, 2-naphthylamine (2-NA), p-cresidine (p-CD), p-toluidine (p-TD), o/m-toluidine (o/m-TD), 4-chloroaniline (4-CA), 4,4'-methylenedi-o-toluidine (4,4'-MDA), and 2,6-dimethylaniline (2,6-DMA) were found in urine at a detection frequency (DF) in the range of 68-100%. Aniline and 2,6-DMA were the predominant compounds found at median concentrations of 6.0 and 3.81 ng/mL, respectively. Intraclass correlation coefficients (ICCs) of all urinary AA concentrations, except for 4-CA, showed moderate to poor predictability (ICC values ranged 0.248-0.697). Gender and ethnicity-related variations in ∑8AA concentrations were significant. Spearman's correlations among AA concentrations suggested that the sources of exposure were not related to tobacco smoke. No significant correlations existed between AAs concentrations and oxidative stress biomarkers (OSBs). The estimated daily intakes of AAs calculated based on urinary concentrations were several orders of magnitude below the tolerable daily intakes.

In Vivo Estimation of the Biological Effects of Endocrine Disruptors in Rabbits after Combined and Long-Term Exposure: Study Protocol

Recently, an increasing number of chemical compounds are being characterized as endocrine disruptors since they have been proven to interact with the endocrine system, which plays a crucial role in the maintenance of homeostasis. Glyphosate is the active substance of the herbicide Roundup^®, bisphenol A (BPA) and di (2-ethylhexyl) phthalate (DEHP) are used as plasticizers, while triclosan (TCS), methyl (MePB), propyl (PrPB), and butyl (BuPB) parabens are used as antimicrobial agents and preservatives mainly in personal care products. Studies indicate that exposure to these substances can affect humans causing developmental problems and problems in the endocrine, reproductive, nervous, immune, and respiratory systems. Although there are copious studies related to these substances, there are few in vivo studies related to combined exposure to these endocrine disruptors. The aim of the present pilot study is the investigation and assessment of the above substances’ toxicity in rabbits after twelve months of exposure to glyphosate (both pure and commercial form) and to a mixture of all the above substances at subtoxic levels. The lack of data from the literature concerning rabbits’ exposure to these substances and the restrictions of the 3Rs Principle will result in a limited number of animals available for use (four animals per group, twenty animals in total).

Insights overview on the possible protective effect of chitosan nanoparticles encapsulation against neurotoxicity induced by carbendazim in rats

Carbendazim (CBZ) contamination of food and water is a principal factor in many negative impacts on public health. Nanoencapsulation of agrochemicals by nontoxic polymers as chitosan nanoparticles (CS-NPs) is one of the most applications of nanotechnology in agriculture. Despite its many advantages, such as it provides controlled release property, more stability and solubility of the active ingredient, it is not authorized to be used in the market because there are no adequate studies on the nano pesticides induced toxicity on experimental animals. So, we aim to study the possible impacts of CBZ-loading CS-NPs on the whole brain of rats and to explain its mechanism of action. 20 male Wistar rats were partitioned into 4 groups as follows: Group (1), normal saline; group (2), 5 mg/kg CS-NPs; group (3), 300 mg/kg CBZ; group (4) 300 mg/kg CS/CBZ-NCs. After 28 days, some neurobehavioral parameters were assessed to all rats then euthanization was done to collect the brain. Our results revealed that CBZ prompted neurotoxicity manifested by severe neurobehavioral changes and a significant increase of MDA with a decrease of GSH and CAT in brain tissue. In addition, there were severe neuropathological alterations confirmed by immunohistochemistry which showed strong bax, GFAP, and TNF-ὰ protein expression in some brain areas. CBZ also induced apoptosis manifested by up-regulation of JNK and P53 with down-regulation of Bcl-2 in brain tissue. Otherwise, encapsulation of CBZ with CS-NPs could reduce CBZ-induced neurotoxicity and improve all studied toxicological parameters. We recommend using CBZ-loading CS-NPs as an alternative approach for fungicide application in agricultural and veterinary practices but further studies are needed to ensure its safety on other organs.

Occupational exposures to pesticides and other chemicals: a New Zealand motor neuron disease case–control study

Objectives

To assess associations between occupational exposures to pesticides and other chemicals and motor neuron disease (MND).

Methods

A population-based case–control study that included 319 MND cases (64% male/36% female) recruited through the New Zealand MND Association complemented with hospital discharge data, and 604 controls identified from the Electoral Roll. For each job held, a questionnaire collected information on 11 exposure categories (dust, fibres, tobacco smoke, fumes, gas, fumigants, oils/solvents, acids/alkalis, pesticides, other chemicals and animals/animal products). ORs were estimated using logistic regression adjusting for age, sex, ethnicity, socioeconomic status, education, smoking, alcohol consumption, physical activities, head/spine injury and other occupational exposures.

Results

Two exposure categories were associated with increased MND risks: pesticides (OR 1.70, 95% CI 1.17 to 2.48) and fumigants (OR 3.98, 95% CI 1.81 to 8.76), with risks increasing with longer exposure duration (p<0.01). Associations were also observed for: methyl bromide (OR 5.28, 95% CI 1.63 to 17.15), organochlorine insecticides (OR 3.28, 95% CI 1.18 to 9.07), organophosphate insecticides (OR 3.11, 95% CI 1.40 to 6.94), pyrethroid insecticides (OR 6.38, 95% CI 1.13 to 35.96), inorganic (copper) fungicides (OR 4.66, 95% CI 1.53 to 14.19), petrol/diesel fuel (OR 2.24, 95% CI 1.27 to 3.93) and unspecified solvents (OR 1.91, 95% CI 1.22 to 2.99). In women, exposure to textile fibres (OR 2.49, 95% CI 1.13 to 5.50), disinfectants (OR 9.66, 95% CI 1.29 to 72.44) and cleaning products (OR 3.53, 95% CI 1.64 to 7.59) were also associated with MND; this was not observed in men (OR 0.80, 95% CI 0.44 to 1.48; OR 0.72, 95% CI 0.29 to 1.84; OR 0.57, 95% CI 0.21 to 1.56, respectively).

Conclusions

This study adds to the evidence that pesticides, especially insecticides, fungicides, and fumigants, are risk factors for MND.

Antibacterial effects of nano-decoction iron polysulfide in epididymitis and the systematic evaluation of its toxicity on the reproductive health of male mice

Ferrous iron and polysulfide (Fe(II)S_n aq) is a nano-decoction. It is usually prepared from the suspension of iron sulfide nanomaterial, using autoclave and centrifugation. A previous study conducted in our laboratory revealed that Fe(II)S_n aq was highly antibacterial, and it could efficiently kill more than 90% population of Escherichia coli and Staphylococcus aureus, within 5 min of the treatment. Our study reported that the intravenous administration of Fe(II)S_n aq provided effective treatment against epididymis infection, caused by S. aureus. The results of the study further highlighted its potential for clinical application. However, its effects on the reproductive system and overall health of mammals have not been investigated earlier. The present study assessed the impacts of Fe(II)S_n aq on reproductive health and other aspects of male mice. Briefly, male mice were exposed to Fe(II)S_n aq, either intravenously at the dose of 0.7 mM, 1.4 mM, and 2.8 mM of Fe²⁺or orally at the dose of 1.4 mM, 2.8 mM, and 5.6 mM of Fe²⁺. Following this, body weight, organs index, quality of sperm, blood biochemical markers, histopathology of organs, oxidative stress and apoptosis were evaluated, after 1 day and 30 days of exposure. In addition, male reproductivity was evaluated in terms of mating with female mice, and the body weight of the resulting offspring was recorded. Our results showed that the mice processed with Fe(II)S_n aq exhibited normal physiological status and reproductive capability. The present study illustrated the short- and long-term influences of Fe(II)S_n aq on the fertility of male mice for the first time. The findings of the study provided a valuable reference for the application of Fe(II)S_n aq, particularly in terms of reproductive safety.

Systematic Review of Calcium Channels and Intracellular Calcium Signaling: Relevance to Pesticide Neurotoxicity

Pesticides of different chemical classes exert their toxic effects on the nervous system by acting on the different regulatory mechanisms of calcium (Ca2+) homeostasis. Pesticides have been shown to alter Ca2+ homeostasis, mainly by increasing its intracellular concentration above physiological levels. The pesticide-induced Ca2+ overload occurs through two main mechanisms: the entry of Ca2+ from the extracellular medium through the different types of Ca2+ channels present in the plasma membrane or its release into the cytoplasm from intracellular stocks, mainly from the endoplasmic reticulum. It has also been observed that intracellular increases in the Ca2+ concentrations are maintained over time, because pesticides inhibit the enzymes involved in reducing its levels. Thus, the alteration of Ca2+ levels can lead to the activation of various signaling pathways that generate oxidative stress, neuroinflammation and, finally, neuronal death. In this review, we also discuss some proposed strategies to counteract the detrimental effects of pesticides on Ca2+ homeostasis.

Metal exposure and oxidative stress biomarkers in a Brazilian agricultural community

We examined the association between exposure to metals, metalloids, and oxidative stress biomarkers among rural community residents in Brazil. Multiple linear regression was used to evaluate associations between serum metal and metalloid concentrations and blood oxidative stress biomarkers, adjusting for sex, age, education, smoking, and alcohol use. After adjustment for covariates, glutathione peroxidase activity (GPx) was inversely and significantly associated with an increase in serum arsenic (As) levels. Positive and significant associations were seen between elevated glutathione reductase (GR) activity and serum cadmium (Cd), barium (Ba), and lead (Pb) concentrations. In addition, we observed a significant increase in malondialdehyde (MDA) levels in association with an increase in Ba levels. These findings suggest that toxic metals and metalloids such as As, Ba, Cd, and Pb alter antioxidant enzyme activities. In addition, Ba seems to promote lipid peroxidation.

Commentary: Novel strategies and new tools to curtail the health effects of pesticides

BACKGROUND

Flaws in the science supporting pesticide risk assessment and regulation stand in the way of progress in mitigating the human health impacts of pesticides. Critical problems include the scope of regulatory testing protocols, the near-total focus on pure active ingredients rather than formulated products, lack of publicly accessible information on co-formulants, excessive reliance on industry-supported studies coupled with reticence to incorporate published results in the risk assessment process, and failure to take advantage of new scientific opportunities and advances, e.g. biomonitoring and "omics" technologies.

RECOMMENDED ACTIONS

Problems in pesticide risk assessment are identified and linked to study design, data, and methodological shortcomings. Steps and strategies are presented that have potential to deepen scientific knowledge of pesticide toxicity, exposures, and risks. We propose four solutions: (1) End near-sole reliance in regulatory decision-making on industry-supported studies by supporting and relying more heavily on independent science, especially for core toxicology studies. The cost of conducting core toxicology studies at labs not affiliated with or funded directly by pesticide registrants should be covered via fees paid by manufacturers to public agencies. (2) Regulators should place more weight on mechanistic data and low-dose studies within the range of contemporary exposures. (3) Regulators, public health agencies, and funders should increase the share of exposure-assessment resources that produce direct measures of concentrations in bodily fluids and tissues. Human biomonitoring is vital in order to quickly identify rising exposures among vulnerable populations including applicators, pregnant women, and children. (4) Scientific tools across disciplines can accelerate progress in risk assessments if integrated more effectively. New genetic and metabolomic markers of adverse health impacts and heritable epigenetic impacts are emerging and should be included more routinely in risk assessment to effectively prevent disease.

CONCLUSIONS

Preventing adverse public health outcomes triggered or made worse by exposure to pesticides will require changes in policy and risk assessment procedures, more science free of industry influence, and innovative strategies that blend traditional methods with new tools and mechanistic insights.

Epidemiological Research on Occupational and Environmental Carcinogens

The cancer risk associated with exposure to environmental and occupational carcinogens such as asbestos, benzene, radiation, or lifestyle carcinogens such as cigarette smoking depends on the entire history of exposure to the carcinogen, including the age of exposure and the time-varying intensity of exposure [...].