A comprehensive review on experimental and clinical findings in intermediate syndrome caused by organophosphate poisoning

A Case Presentation in Management of Dysphagia and Dysarthria Caused due to Organophosphorus and Carbamate Insecticide Poisoning

Organophosphorus and carbamate Insectiside is common in Asia-Pacific region consisting of 63% of the Global death. Organophosphorus and Carbamate poisoning can lead into different complications in the respiratory,digestive,neurological aspects and maybe fatal in certain cases.Besides medical management of the same,early rehabilitation is also required to manage different kinds of neurological aspects caused due to Organophosphorus and carbamate poisoning. The study was done to introspect the early intervention in swallowing and speech therapy in organophosphorus and carbamate poisoning individual,as a part of management besides medical intervention. A 19 years old female reported to the hospital with history of consuming organophos and carbamate insecticide with the intention of self harming causing cardiac arrest and as diagnosed as Flaccid Dysarthria with Oro-Pharyngeal Dysphagia when assessed with diagnostic tools respectively. Early speech and swallowing intervention was provided and introspected using MASA which showed improvement in scores during the therapeutic intervention and was statistically analysed using linear regression analysis. The result showed the improvement in MASA scores (the slope of the best fit) and proved that MASA scores improved significantly (slope = 14.3, p < 0.05) over time as the therapy sessions proceeded. The regression model was also significant (p < 0.05). The motor-speech therapeutic intervention provided improvement in the kinematics of oro-motor skills along with improvement in intelligibility of speech. This study concludes that early intervention in managing speech and swallowing abilities in Dysarthria and Dysphagia is helpful besides medical intervention in such cases.

A Comprehensive Physiotherapy Approach to Regain Functional Independence in Intermediate Syndrome Secondary to Organophosphate Poisoning: A Case Report

Organophosphate poisoning (OPP) remains a significant public health issue globally, particularly in middle- and low-income countries. This study aimed to assess the effectiveness of physiotherapy interventions in managing patients with OPP, focusing on reducing the severity of intermediate syndrome symptoms and associated complications such as respiratory muscle weakness and bilateral loculated pleural effusions. A 48-year-old male with a history of alcohol consumption was transferred to the medicine intensive care unit due to poison ingestion. The patient exhibited symptoms of respiratory distress and decreased consciousness, necessitating intubation and mechanical ventilation. Physiotherapy interventions included patient education, secretion mobilization, vital capacity improvement, secondary complication prevention, chest expansion exercises, dyspnea-relieving positions, and mobilization. The patient's progress was monitored using various scales, including the Functional Independence Measure Scale, ICU Mobility Scale, and Chelsea Critical Care Physical Assessment Tool. Significant improvements in functional independence, mobility, and psychological well-being were observed throughout the intervention period. This study highlights the importance of physiotherapy in the comprehensive management of OPP, emphasizing its role in mitigating respiratory complications and improving overall functional outcomes.

Ginseng Stem-and-Leaf Saponins Mitigate Chlorpyrifos-Evoked Intestinal Toxicity In Vivo and In Vitro: Oxidative Stress, Inflammatory Response and Apoptosis

In recent years, the phenomenon of acute poisoning and organ damage caused by organophosphorus pesticides (OPs) has been a frequent occurrence. Chlorpyrifos (CPF) is one of the most widely used organophosphorus pesticides. The main active components of ginseng stems and leaves are total ginseng stem-and-leaf saponins (GSLSs), which have various biological effects, including anti-inflammatory, antioxidant and anti-tumor activities. We speculate that these could have great potential in the treatment of severe diseases and the relief of organophosphorus-pesticide-induced side effects; however, their mechanism of action is still unknown. At present, our work aims to evaluate the effects of GSLSs on the antioxidation of CPF in vivo and in vitro and their potential pharmacological mechanisms. Mice treated with CPF (5 mg/kg) showed severe intestinal mucosal injury, an elevated diamine oxidase (DAO) index, the decreased expression of occlusive protein-1 (ZO-1) and occlusive protein, an impaired intestinal mucosal oxidation system and intestinal villi relaxation. In addition, chlorpyrifos exposure significantly increased the contents of the inflammatory factor TNF-α and the oxidative-stress-related indicators superoxide dismutase (SOD), catalase (CAT), glutathione SH (GSH), glutathione peroxidase (GSH-PX), reactive oxygen species (ROS) and total antioxidant capacity (T-AOC); elevated the level of lipid peroxide malondialdehyde (MDA); reversed the expression of Bax and caspase; and activated NF-κB-related proteins. Interestingly, GSLS supplementation at doses of 100 and 200 mg/kg significantly reversed these changes after treatment. Similar results were observed in cultured RAW264.7 cells. Using flow cytometry, Hoechst staining showed that GSLSs (30 μg/mL, 60 μg/mL) could improve the cell injury and apoptosis caused by CPF and reduce the accumulation of ROS in cells. In conclusion, GSLSs play a protective role against CPF-induced enterotoxicity by inhibiting NF-κB-mediated apoptosis and alleviating oxidative stress and inflammation.

Suspected intermediate syndrome in a dog after organophosphate poisoning

OBJECTIVE

To discuss the clinical presentation and successful treatment of a suspected case of intermediate syndrome due to organophosphate (OP) poisoning in a dog.

CASE SUMMARY

Two dogs presented with acute cholinergic signs after ingesting an OP insecticide containing 50% acephate. Clinical signs consistent with acute cholinergic crisis resolved in both dogs within 24 hours postingestion. One dog developed an onset of neurological signs consistent with intermediate syndrome approximately 24 hours postingestion. This patient's clinical signs resolved with the use of pralidoxime chloride.

NEW OR UNIQUE INFORMATION PROVIDED

OP poisoning most commonly presents as an acute cholinergic crisis, with rare instances of animals developing intermediate syndrome. Few reports of successful treatment and recovery from intermediate syndrome exist in the veterinary literature, particularly with instances in which 2 dogs within the same exposure setting were treated for acute cholinergic signs and only 1 progressed to an intermediate syndrome. This report also highlights the importance of early intervention with pralidoxime chloride prior to the onset of aging.

Severe acute organophosphate poisoning managed with 2-month prolonged atropine therapy: a case report

Introduction and Importance

Organophosphate (OP) poisoning is a common and potentially fatal condition that requires prompt and aggressive treatment with atropine, oximes, and supportive care. We report a rare case of OP poisoning that needed high doses of atropine and intensive care for 60 days.

Case Presentation

A 39-year-old male ingested 200 ml of chlorpyrifos, an OP compound, and presented with vomiting and epigastric pain. He received an initial dose of atropine of 60 ml (36 mg, 1 ml=0.6 mg), followed by an infusion of 16 ml/h (9.6 mg/h). He developed hypoxia, cardiac arrest, delirium, fever, and persistent bronchorrhea. He was intubated, resuscitated, and transferred to ICU, where he continued showing signs of OP excess and therefore, he received up to 170 ml/h (102 mg/h) of atropine infusion, along with triple inotropes and sedation. He underwent tracheostomy and gradual weaning of atropine. He recovered completely and was discharged in stable condition.

Clinical Discussion

This case demonstrates the need for prolonged monitoring of patients with OP poisoning wherein the patient can develop signs of OP excess even after initial atropinization, the effectiveness of multiple doses of atropine in OP poisoning, and the importance of monitoring for complications associated with a prolonged hospital stay. It also shows the potential need for prolonged atropine therapy and intensive care in OP poisoning.

Conclusion

OP poisoning can be life-threatening and requires early and aggressive treatment with atropine, oximes, and supportive care. Clinicians should be aware of the potential need for prolonged atropine therapy in OP poisoning cases to improve the chances of survival.

Zinc Phosphide Poisoning: From A to Z

Zinc phosphide is a rodenticide that is used in agricultural, urban and industrial environments in México. After ingestion, it reacts with hydrochloric acid, hydrolyzing into phosphine. It causes cellular hypoxia via mitochondrial toxicity, resulting in multiple organ dysfunction and death. There is no antidote or specific treatment for zinc phosphide toxicity. We present the case of a 45-year-old female who ingested zinc phosphide with suicidal intent. On arrival at the emergency department, she had multisystemic disorders. Supportive care, decontamination and antidotal therapy were initiated. Subsequently, she evolved to clinical improvement with a resolution of the biochemical abnormalities of tissue hypoperfusion. She was discharged on day 7 without complications. In this review, we provide updated therapeutic options and discuss their specific pathophysiological basis.

Multiple neurological effects associated with exposure to organophosphorus pesticides in man

This article reviews available data regarding the possible association of organophosphorus (OP) pesticides with neurological disorders such as dementia, attention deficit hyperactivity disorder, neurodevelopment, autism, cognitive development, Parkinson's disease and chronic organophosphate-induced neuropsychiatric disorder. These effects mainly develop after repeated (chronic) human exposure to low doses of OP. In addition, three well defined neurotoxic effects in humans caused by single doses of OP compounds are discussed. Those effects are the cholinergic syndrome, the intermediate syndrome and organophosphate-induced delayed polyneuropathy. Usually, the poisoning can be avoided by an improved administrative control, limited access to OP pesticides, efficient measures of personal protection and education of OP pesticide applicators and medical staff.

How the exposure to environmentally relevant pesticide formulations affects the expression of stress response genes and its relation to oxidative damage and genotoxicity in Caiman latirostris

This study aimed to analyze the molecular stress responses thought the expression levels of catalase (cat), superoxide dismutase (sod) and heat shock protein 70 (hsp70) genes, and how these relate with cellular stress response considering oxidative damage to lipids, DNA and genotoxicity in blood of Caiman latirostris hatchlings exposed to pesticide formulations under ex situ conditions. Treatments were: negative control (NC-tap water), glyphosate 2% (GLY), cypermethrin 0.12% (CYP), chlorpyrifos 0.8% (CPF), and their ternary mixture (Mx3). The concentrations and schedule of application were those recommended in soybean crops. Soil and water showed pesticides residues in all exposed groups. Results showed a statistically significant increase in the micronucleus frequency and DNA damage, with an important oxidation in all exposed groups. The expression level of cat gene was significantly higher in CYP while the expression of hsp70 was significantly lower in GLY, CYP and Mx3, compared to NC. Pesticides tested showed alterations in expression levels, growth parameters, DNA damage and base oxidation under realistic exposure conditions, and can threaten, in the long term, the health status of wild populations.

Risk assessment of oxidative stress and multiple toxicity induced by Etoxazole

Etoxazole is among the systemic pesticides with acaricidal and insecticidal characteristics. This paper reports the first evaluation of the toxic effects of Etoxazole on Allium cepa L. Etoxazole solutions were applied to three groups formed from A. cepa bulbs at 0.125 mL/L, 0.25 mL/L and 0.5 mL/L doses, respectively. The control group was treated with tap water throughout the experimental period. The toxic effects of Etoxazole became more apparent as the dose of Etoxazole was increased. The growth-limiting effect was most pronounced in the highest dose group with approximately 29%, 70% and 58.5% reductions in germination percentage, root elongation and weight gain, respectively. The genotoxic effect of Etoxazole was most severe in the 0.5 mL/L dose group. In this group, the mitotic index decreased by 30% compared to the control group, while the micronucleus frequency increased to 45.3 ± 3.74. The most observed aberrations were fragment, vagrant chromosome, sticky chromosome, unequal distribution of chromatin, bridge, reverse polarization and nucleus with vacuoles. The malondialdehyde level showed a gradual increase with increasing Etoxazole doses and reached 2.7 times that of the control group in the 0.5 mL/L Etoxazole applied group. Catalase and Superoxide dismutase activities increased in the groups exposed to 0.125 mL/L and 0.25 mL/L Etoxazole with dose dependence and decreased abruptly in the group treated with 0.5 mL/L Etoxazole. Etoxazole triggered meristematic cell damages, such as epidermis cell damage, thickening of cortex cell walls, flattened cell nucleus and indistinct transmission tissue. Considering the versatile toxicity induced by Etoxazole, we announce that this chemical has the potential to cause serious damage to non-target organisms. It should be noted that the higher the dose of exposure, the more severe the level of damage. This study will be an important reminder to limit the indiscriminate use of this highly risky agrochemical.

Organophosphate Insecticide Toxicity in Neural Development, Cognition, Behaviour and Degeneration: Insights from Zebrafish

Organophosphate (OP) insecticides are used to eliminate agricultural threats posed by insects, through inhibition of the neurotransmitter acetylcholinesterase (AChE). These potent neurotoxins are extremely efficacious in insect elimination, and as such, are the preferred agricultural insecticides worldwide. Despite their efficacy, however, estimates indicate that only 0.1% of organophosphates reach their desired target. Moreover, multiple studies have shown that OP exposure in both humans and animals can lead to aberrations in embryonic development, defects in childhood neurocognition, and substantial contribution to neurodegenerative diseases such as Alzheimer's and Motor Neurone Disease. Here, we review the current state of knowledge pertaining to organophosphate exposure on both embryonic development and/or subsequent neurological consequences on behaviour, paying particular attention to data gleaned using an excellent animal model, the zebrafish (Danio rerio).

Poisoning by Organophosphate Pesticides: A Case Report

In many parts of the world, particularly in impoverished nations like Ethiopia, organophosphate compounds operate as suicide agents, are frequently employed as pesticides, and are strong inhibitors of the acetylcholinesterase enzyme. A 21-year-old Ethiopian female, a university student, was admitted to an emergency department on June 22, 2022, with a two-hour history of nausea and elevated secretions of salivation via the mouth. She had no previous history of psychiatric or neurological disorders, but three days before her admission, she quarreled with her boyfriend, became extremely depressed, and decided to commit suicide. She had a two-hour history of nausea and intermittent vomiting and a one-hour history of persistent vomiting, increased salivation secretions through the mouth, chills, progressive sweating, difficulty breathing, and dizziness. Upon admission, her neurological examination in the emergency department revealed a Glasgow Coma Scale score of 9/15. On admission, she was placed on two liters per minute of intranasal oxygen via the nasal cannula. On the same day, she was given atropine 0.15 mg intravenously, and the dose was doubled every 10 minutes until atropinization was achieved, and a bolus dose of 500ml of 0.9% of normal saline was initiated immediately.

Prevalence, clinical manifestations, laboratory findings, treatment, and outcome of intermediate syndrome in anticholinesterase pesticide intoxication of dogs: A retrospective study

Organophosphates and carbamates are important anticholinesterase intoxicants of humans and dogs. Intermediate syndrome (IMS) typically occurs 7-96 h following a toxicity-associated acute cholinergic crisis (ACC), and manifests clinically as weakness of the proximal limb, respiratory, and neck flexor muscles. The aim of this study was to describe the prevalence, clinical findings, and outcome of IMS in dogs. The medical records of a veterinary teaching hospital were searched for dogs diagnosed with ACC, IMS, or both, between 2017 and 2021. Case files were retrospectively reviewed. Six historical IMS cases were additionally reviewed. Thirty-two dogs were diagnosed with anticholinesterase intoxication during the search period, of which 23 (72 %) were only diagnosed with ACC, seven (22 %) progressed from ACC to IMS, and two (6 %) were only diagnosed with IMS. Duration of hospitalisation was longer in the IMS group compared to the ACC only group (P = 0.005). When all dogs with IMS (n = 15, including the six historical cases) were considered, survival was 100 %, including four (27 %) that required positive pressure mechanical ventilation following respiratory failure. Serum butyrylcholine esterase activity, a marker of cholinesterase activity, was below reference interval when first measured in 14 (93 %) of dogs; however, was not a useful as a recovery marker. IMS should be suspected in dogs demonstrating respiratory, neck, and proximal limb muscle paresis or paralysis, especially following clinical signs consistent with ACC. Absence of clinical signs consistent with ACC or butyrylcholine esterase activity within the reference interval does not exclude IMS as a differential.

Occupational risk assessment of organophosphates with an emphasis on psychological and oxidative stress factors

Organophosphate pesticides (OPPs) are widely used all over the world in domestic and industrial settings, but these chemicals affect the nervous system, induce suicidal thoughts, depression and anxiety, and impair sleep quality. The purpose of this study was to investigate the relationship between the main toxicity mechanisms of OPPs, oxidative stress and cholinesterase inhibition, and psychological parameters in chronic exposure to OPPs. This cross-sectional study was conducted on 56 male OPPs factory workers as the worker group and 47 unexposed individuals within the same age range as the control group. Psychological factors were assessed using validated questionnaires. The activity of plasma cholinesterase and oxidative stress biomarkers, total antioxidant capacity of plasma, lipid peroxidation (LPO), and protein carbonylation were determined in blood samples by spectrophotometer. Sleep quality score in the factory workers was lower, and depression and suicidal ideation scores were higher than those in the control group. These factory workers showed 35% lower levels of plasma cholinesterase activity than did the controls. Compared to the control group, a significant impairment in oxidative stress biomarkers was also observed in the workers. Meanwhile, there was a significant relationship between the duration of employment and the level of LPO as well as a significant correlation between the quality of sleep and plasma cholinesterase in the workers. In conclusion, long-term exposure to OPPs could cause oxidative damages and neurobehavioral effects. The close monitoring of workplace exposure to organophosphates pesticides and also their respective solvents along with the reduction of working hours are of the necessities to avoid the adverse impacts of exposure to these pesticides.

Soman (GD) Rat Model to Mimic Civilian Exposure to Nerve Agent: Mortality, Video-EEG Based Status Epilepticus Severity, Sex Differences, Spontaneously Recurring Seizures, and Brain Pathology

Modeling a real-world scenario of organophosphate nerve agent (OPNA) exposure is challenging. Military personnel are premedicated with pyridostigmine, which led to the development of OPNA models with pyridostigmine/oxime pretreatment to investigate novel therapeutics for acute and chronic effects. However, civilians are not premedicated with pyridostigmine/oxime. Therefore, experimental models without pyridostigmine were developed by other laboratories though often only in males. Following OPNA exposure, prolonged convulsive seizures (CS) or status epilepticus (SE) are concerning. The duration and severity of CS/SE determine the extent of brain injury in survivors even after treating with medical countermeasures (MCM)/antidotes such as atropine, an oxime, and an anticonvulsant such as diazepam/midazolam. In this study, using a large mixed sex cohort of adult male and female rats, without pretreatment, we demonstrate severe SE lasting for >20 min in 82% of the animals in response to soman (GD,132 μg/kg, s.c.). Atropine sulfate (2 mg/kg, i.m.) and HI-6 (125 mg/kg, i.m.) were administered immediately following soman, and midazolam (3 mg/kg, i.m.) 1 h post-exposure. Immediate MCM treatment is impractical in civilian exposure to civilians, but this approach reduces mortality in experimental models. Interestingly, female rats, irrespective of estrous stages, had an average of 44 min CS (stage ≥ 3), while males had an average of 32 min CS during SE, starting from soman exposure to midazolam treatment. However, in telemetry device implanted groups, there were no significant sex differences in SE severity; males had 40 min and females 43 min of continuous CS until midazolam was administered. No animals died prior to midazolam administration and less than 5% died in the first week after soman intoxication. In telemetered animals, there was a direct correlation between EEG changes and behavioral seizures in real-time. In the long-term, convulsive spontaneously recurring seizures (SRS) were observed in 85% of randomly chosen animals. At 4-months post-soman, the brain histology confirmed reactive gliosis and neurodegeneration. The novel findings of this study are that, in non-telemetered animals, the SE severity following soman intoxication was significantly greater in females compared to males and that the estrous cycle did not influence the response.

Assessment of the Serum Glucose/Potassium GLU/K Ratio as a Predictor of Intermediate Syndrome Following Acute Anticholinesterase Exposure

BACKGROUND

The widespread use of anticholinesterase-containing pesticides accounts for the considerable morbidity and mortality in Egypt and worldwide.

AIM

Few studies have investigated the predictors of intermediate syndrome (IMS). Therefore, in this study, we assessed the adequacy of the serum glucose/potassium (GLU/K) ratio as an early reliable tool to predict IMS incidence following intoxication with acute anticholinesterase compounds.

METHODS

A prospective cross-sectional study was conducted among patients who presented to Tanta University Poison Control Center, Egypt, and were diagnosed with acute anticholinesterase intoxication between January and August, 2021. Patients were categorized based on the primary outcome into IMS (+) and IMS (-) groups.

RESULTS

Overall, 243 patients were included, among whom 44 (18.1%) had IMS as the complication. Younger individuals with age ranging between 18 and <25 years constituted the main exposed age category in both groups. Vomiting and abdominal colic were the most commonly noted complaints in the included patients (94.2% and 63.8% of patients, respectively). The delay, length of hospital stay, mean blood pressure, O₂ saturation, Glasgow Coma Scale score, random blood glucose level, K concentration, GLU/K ratio, and dose of atropine administered were significant IMS predictors on an individual basis, and the GLU/K ratio was the most significant IMS predictor. At a cutoff value of >41.07%, the GLU/K ratio could significantly predict IMS (areas under the curves = 0.971, p < 0.001) with 93% accuracy, 93.2% sensitivity, and 93% specificity.

CONCLUSION

Although the clear pathophysiology of IMS remains to be elucidated, our results provide insight into the significant contribution of neurological affection, apart from the well-known direct toxic effect on muscles. Moreover, we demonstrated a significant association between the development of IMS and severity of organophosphorus compounds' exposure. Physicians should be vigilant to detect IMS early upon admission using the GLU/K ratio, which is a useful early IMS predictor.

Patterns of cardio-respiratory motor outputs during acute and subacute exposure to chlorpyrifos in an ex-vivo in situ preparation in rats

While a considerable body of literature has characterized the clinical features induced by organophosphate pesticides, the field lacks scrutiny into cardio-respiratory changes in different phases of poisoning. Herein, we evaluated the impact of chlorpyrifos (CPF) and its active metabolite chlorpyrifos-oxon (CPO) on the cardiorespiratory system during acute and subacute phases of poisoning using an in situ experimental rodent model. CPF (30 mg/kg) was injected intraperitoneally to rats beforehand (24 h) whereas CPO (15 mg/kg) was added into the perfusate reservoir to evaluate the effects on the motor outputs throughout the three phases of the respiratory cycle: inspiration, post-inspiration and late expiration. Phrenic, recurrent laryngeal (RLN) and thoracic sympathetic nerve activity (tSNA) were recorded. Heart rate was derived from the electrocardiogram (ECG) and the baro- and chemo-reflexes tested. CPF and CPO led to a time-dependent change in cardiorespiratory motor outputs. In the acute phase, the CPO induced bradypnea, transiently reduced the inspiratory time (TI), and increased the amplitude of phrenic. Post-inspiratory (PI) discharge recorded from the RLN was progressively reduced while tSNA was increased. CPO significantly depressed the chemoreflex but had no effect on baroreflex. During subacute phase, CPF prolongated T_I with no effect on respiratory rate. Both the RLN PI discharge, the chemoreflex and the baroreflex sympathetic gain were reduced. In addition, both CPF and CPO shifted the cardiac sympatho-vagal balance towards sympathetic dominance. Our data show that different phases of poisoning are associated with specific changes in the cardio-respiratory system and might therefore demand distinct approaches by health care providers.

Toxicity in Peripheral Nerves: An Overview

Introduction to a collection. This article is intended to introduce a collection of papers on toxic neuropathies. Toxic neuropathies can be caused by a variety of substances and by different mechanisms. Toxic agents are numerous and can be distinguished between drugs, recreational agents, heavy metals, industrial agents, pesticides, warfare agents, biologic substances and venoms. Toxic agents reach the nervous system by ingestion, transcutaneously, via the mucous membranes, parenterally and by aerosols. The most frequent types are cumulative toxicities. Other types are acute or delayed toxicities. Pathogenetic mechanisms range from a specific toxic substance profile causing axonal or demyelinating lesions, towards ion channel interferences, immune-mediated mechanisms and a number of different molecular pathways. In addition, demyelination, focal lesions and small fiber damage may occur. Clinically, neurotoxicity presents most frequently as axonal symmetric neuropathies. In this work, we present a panoramic view of toxic neuropathy, in terms of symptoms, causes, mechanisms and classification.

Forensic analysis of soman exposure using characteristic fragment ions from protein adducts

The verification of exposure to nerve agents is a serious challenge, especially in cases of soman (GD) poisoning. Protein adducts are reliable biomarkers, that provide forensic information and evidence during incidents of terrorism or sporadic poisoning. Mass spectrometry, coupled with a proteomics approach, was established for the forensic analysis of GD-based protein adducts. The fragmentation pathways of GD-based protein adducts were investigated for the first time using electrospray ionization tandem mass spectrometry. Three abundant natural loss product ions, [M+2H-54]²⁺ (loss of two carbon cations), [M+2H-72]²⁺ (loss of tert-butyl and methyl moieties), and [M+2H-84]²⁺ (loss of the pinacolyl moieties), were observed in each of the GD-labeled adducts, and the product ions were independent of protein structure and exposure route. A unique mechanism for the formation of product ions involving GD-protein adducts is proposed here. These findings support the development of a simple and precise forensic analysis technique to rapidly verify GD poisoning using these three GD-related product ions.

Evaluating Hemolytic and Photo Hemolytic Potential of Organophosphorus by In Vitro Method as an Alternative Tool Using Human Erythrocytes

AIMS

The present study aims to determine the phototoxic and haemolytic activity of organophosphorus. The use of alternative in vitro assays with human erythrocytes is suggested to predict the polluting effect of these products on health.

METHODOLOGY

Human erythrocytes from Toluca Blood Bank were used. Sodium dodecyl sulfate was employed as a positive control. Additionally, the haemolysis percentage of three organophosphate (Acetate, Chlorpyrifos, Malathion, Methamidophos, Methyl Parathion) induced photo haemolysis formulated with surfactants on a concentration of 2 x 109 erythrocytes were evaluated. Finally, the products were classified as irritant or phototoxic.

RESULTS

Results showed that the HC50 red blood cells were similar for each organophosphate (Malathion and Methamidophos) indicating very irritant action with ratio classification (L/D) of 0.041 and 0.053, respectively. On the other hand, Chlorpyrifos was classified as an irritant with L/D= 0.14. On the other hand, the HC50 obtained photo hemolysis assays irradiated red blood cells was similar for each organophosphate (Acetate, Chlorpyrifos, Malathion, Methamidophos, Methyl Parathion) indicating no phototoxic action.

CONCLUSION

As a conclusion, it can be said that the parameters of haemolysis and denaturation of proteins are good indicators to classify organophosphorus formulated with surfactants as irritating or phototoxic.

The implication of ROS production on triflumuron-induced oxidative stress and genotoxicity in human colon carcinoma (HCT-116) cells

The aim of this study is to evaluate the cytotoxic and the genotoxic effects of triflumuron (TFM) on human colon carcinoma cells (HCT-116). Indeed, TFM is used to protect vegetables, fruits, and domestic animals against a large spectrum of parasites causing animal and human disorders. However, studies revealing its toxicity and its mode of action in mammalian systems remain very limited. We monitored our work with the cytotoxicity assay starting with the cell viability test, the ROS generation, the malondialdehyde (MDA) production, the DNA fragmentation, and the measurement of some antioxidant enzymes activities such as catalase, superoxide dismutase, and the glutathione S-transferase. Also, we measured the mitochondrial transmembrane potential. We showed that TFM induced a dose-dependent cell death. This decrease in cell viability was accompanied by a significant reduction in the mitochondrial membrane potential. We also have shown that TFM induced oxidative stress as revealed by the generation of reactive oxygen species, the increase of the MDA levels, and the activation of the antioxidant enzymes. Moreover, our results indicated that TFM induced DNA damage in HCT-116 cells as monitored by the comet assay. We demonstrate, for the first time, the cytotoxic and the genotoxic potentials of TFM on human cultured cells.

Triflumuron induces cytotoxic effects on hepatic and renal human cell lines

Insect growth regulator insecticides are a new class of pesticides, commonly used around the world to control insect damages. Among those compounds, we focused our interest on triflumuron (TFM), which is less toxic than other conventional insecticides. However, not much is known about its toxic effects on mammalian systems. Therefore, our study aimed toward evaluating the cytotoxic and genotoxic effects of TFM using two different cell lines, the human renal embryonic cells (HEK 293) and hepatocytes (Hep G2). We showed, according to the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, that TFM reduced significantly the cell viability and increased the reactive oxygen species generation, malondialdehyde levels, and mitochondrial membrane potential in both cell lines. The antioxidant system was disturbed as assessed by the increased activities in both catalase and superoxide dismutase. We demonstrated also, that TFM is an inductor of DNA damages quantified by the comet assay. Moreover, we showed an overexpression of proapoptotic Bax and a decrease in antiapoptotic Bcl-2 expression. As a conclusion, we demonstrate that the liver presents the major target organ to TFM, in which the cytotoxicity and the genotoxic effects were significantly higher in hepatic cells than in renal cells and by consequence its uses must be controlled.

Melatonin Protects Neural Stem Cells Against Tri-Ortho-Cresyl Phosphate-Induced Autophagy

Tri-ortho-cresyl phosphate (TOCP) is an extensively used organophosphate in industry. It has been proven to lead to toxicity in different organ systems, especially in the nervous system. Neural stem cells (NSCs) play important roles in both embryonic and adult nervous systems. However, whether TOCP induces cytotoxicity in embryonic NSCs remains unclear. In this study, mouse NSCs were exposed to different concentrations of TOCP for 24 h. The results showed that TOCP led to impaired proliferation of NSCs and induced the autophagy of NSCs by increasing the generation of intracellular reactive oxygen species (ROS) and decreasing the phosphorylation of extracellular regulated protein kinase (ERK1/2). Melatonin has been reported to exert neuroprotective effects via various mechanisms. Therefore, we further investigate whether melatonin has potential protective effects against TOCP-induced cytotoxicity on NSCs. Our data showed that melatonin pretreatment attenuated TOCP-induced autophagy by suppressing oxidative stress and restoring ERK1/2 phosphorylation consistently. Taken together, the results indicated that TOCP induced the autophagy in mouse NSCs, and melatonin may effectively protect NSCs against TOCP-induced autophagy.

Nerve agents: a guide for emergency nurses. Part 1

Recent incidents in the UK and the alleged chemical attacks in Syria by the Bashar al-Assad regime have brought the subject of chemical weapons back into the public domain. To date these types of event have been relatively rare because terrorist plans to harm large numbers of people have mostly been thwarted. This is the first part of a two-part article on nerve agents. Part one gives an overview of these agents, their historical background and manufacture, and how the agents affect physiology. Part two, which will appear in the next issue, considers the pre-hospital response to the use of nerve agents, including effective triage and decontamination, and in-hospital treatment.

Impact of chlorpyrifos on blood glucose concentration in an animal model: a systematic review and meta-analysis

Chlorpyrifos, an organophosphate insecticide, disturbs blood glucose hemostasis in experimental models and causes metabolic disorders. However, there are controversial findings of its impact on the BS level. The present meta-analysis aimed to investigate blood gluocse levels in rats exposed to chlorpyrifos. Present systematic review and meta-analysis study was done by searching in the online databases, including Google Scholar, Web of Science, PubMed, and Scopus. Data were analyzed by performing "random effects meta-regression." Findings were expressed as standardized mean value and 95% confidence interval (CI). Heterogeneity between studies was assessed using I-square and Q test. Meta-analysis of 7 animal studies indicated the dose-dependence manner of chlorpyrifos exposure on the blood glucose levels. The subgroup analysis indicated that exposure to low doses of chlorpyrifos significantly increased the blood glucose levels in exposed animals versus the nonexposed (0.11; 95% CI: - 1.14, 1.36, z = 2.25, p = 0.03, I2 = 90.1%, p < 0.001) and high doses markedly decreased blood glucose levels in exposed rats versus the nonexposed (7.34; 95%CI: - 9.35, - 5.32, z = 6.41, p < 0.001, I2 = 96.9%, p < 0.001). The random effects and pooled analysis indicated that the blood glucose levels were 4.22-fold lower in exposed animals versus the nonexposed ones (95% CI: - 5.59,- 2.85; Z = 3.97; p < 0.001); therefore, heterogeneity was significant (I2 = 96.5%, p < 0.001). The present finding indicated the association between chlorpyrifos exposure and a decrease in blood glucose levels. However, more studies should be designed to clarify this effect of chlorpyrifos exposure on blood glucose levels and involved mechanisms.

Does oxidative stress contribute to toxicity in acute organophosphorus poisoning? - a systematic review of the evidence

Introduction: Organophosphorus (OP) insecticide self-poisoning is a global problem, killing tens of thousands of people every year. Oxidative stress has been proposed to play a pathological role in OP poisoning, but whether it plays a direct toxic role is currently unclear.Objectives: To determine whether there is consistent evidence of oxidative stress in patients with acute OP insecticide self-poisoning, and whether there are animal or human trial data that indicate that treatment of oxidative stress provides clinical benefit, which would suggest a direct toxic effect of oxidative stress.Methods: We conducted a systematic review using the PubMed, EMBASE and MEDLINE databases, and the Cochrane Database of Systematic reviews, based upon the following search terms and keywords: "organophosphate poisoning", "oxidative stress" and "antioxidant". All articles relevant to the aims of the study were included. Articles related to chronic OP poisoning, to use of medicines without antioxidant benefits, or to subjects other than oxidative stress were excluded. The search returned 256 results of which 17 studies were considered relevant and grouped under the following categories: observational human studies (n = 11) and intervention studies in animals (n = 4) and humans (n = 2).Oxidative stress markers in human studies: Oxidative damage to lipids and proteins was reported in all eleven human studies. Eight of nine studies reported variable increases in a weak marker of lipid peroxidation, malondialdehyde. In two case-control studies, erythrocyte membrane malondialdehyde concentrations were 380% and 160% higher in cases than controls, while plasma malondialdehyde concentrations were ∼63% higher in cases than controls in three case-control studies. In a prospective study, plasma malondialdehyde did not increase significantly from baseline in moderate or severely poisoned patients. Five case-control studies measured thiol residues as markers of protein oxidative damage and found variable changes after poisoning. No evidence of oxidative DNA damage was found in the one study that investigated it.Antioxidant intervention studies in animals: After treatment with an antioxidant, all four studies showed an improvement in either markers of oxidative damage or antioxidant activity. One mouse study with a relatively low risk of bias showed that administration of acetylcysteine 200 mg/kg reduced malondialdehyde by 35% and increased survival by more than 60%.Antioxidant intervention studies in humans: We found two small randomised controlled trials reporting the use of acetylcysteine as an adjunct to standard treatment in acute OP poisoning. The trials found that acetylcysteine reduced atropine requirements by 77% and 55%, but did not affect clinically relevant outcomes.Conclusions: Several studies showed evidence of OP insecticide-induced oxidative damage and antioxidant activity, suggesting that endogenous antioxidant defences are triggered in acute OP poisoning. However, the markers of lipid peroxidation used were weak, there was high inter-individual variability between studies in results and quality, and marked variation between the OP insecticides involved. Animal data provide some evidence that antioxidants alleviate adverse effects of acute poisoning, suggesting that oxidative stress may directly cause clinical harm. Acetylcysteine appeared beneficial in animal studies, but this could be mediated via increased synthesis of the endogenous detoxifying agent, glutathione, rather than through a direct antioxidant effect. The two human clinical studies were too small to provide any clear evidence to support the use of acetylcysteine in OP poisoning. Further research into the mechanisms of oxidative stress in acute OP poisoning, combined with large unambiguous clinical trials of antioxidants, are required before they can be used routinely in treatment.

Prenatal organophosphate insecticide exposure and infant sensory function

BACKGROUND

Occupational studies suggest that exposure to organophosphate insecticides (OPs) can lead to vision or hearing loss. Yet the effects of early-life exposure on visual and auditory function are unknown. Here we examined associations between prenatal OP exposure and grating visual acuity (VA) and auditory brainstem response (ABR) during infancy.

METHODS

30 OPs were measured in umbilical cord blood using gas chromatography tandem mass spectrometry in a cohort of Chinese infants. Grating visual acuity (VA) (n = 179-200) and auditory brainstem response (ABR) (n = 139-183) were assessed at 6 weeks, 9 months, and 18 months. Outcomes included VA score, ABR wave V latency and central conduction time, and head circumference (HC). Associations between sensory outcomes during infancy and cord OPs were examined using linear mixed models.

RESULTS

Prenatal chlorpyrifos exposure was associated with lower 9-month grating VA scores; scores were 0.64 (95% CI: -1.22, -0.06) points lower for exposed versus unexposed infants (p = 0.03). The OPs examined were not associated with infant ABR latencies, but chlorpyrifos and phorate were both significantly inversely associated with HC at 9 months; HCs were 0.41 (95% CI: 0.75, 0.6) cm and 0.44 (95% CI: 0.88, 0.1) cm smaller for chlorpyrifos (p = 0.02) and phorate (p = 0.04), respectively.

CONCLUSIONS

We found deficits in grating VA and HC in 9-month-old infants with prenatal exposure to chlorpyrifos. The clinical significance of these small but statistically significant deficits is unclear. However, the disruption of visual or auditory pathway maturation in infancy could potentially negatively affect downstream cognitive development.

Efficacy and outcomes of lipid resuscitation on organophosphate poisoning patients: A systematic review and meta-analysis

OBJECTIVE

Organophosphate (OP) pesticides are still widely available in developing countries, leading to numerous accidental or suicidal poisonings every year. Lipid emulsion treatments are commonly used in resuscitating OP poisoning patients but few studies regarding their use have been reported. Our meta-analysis aimed to analyze the efficacy and outcomes of lipid resuscitation on OP poisoning patients.

METHODS

A systematic search for associated studies was conducted in Pubmed, EMBASE, MEDLINE, the Cochrane Library and the Chinese National Knowledge Infrastructure. Collected data was pooled using Revman v5.3. Outcomes included prognosis (cured vs. mortality rates), hepatic function (serum ALT, AST, Total Bilirubin (TBIL) level), serum acetylcholinesterase (AchE) level and respiratory function (rate of respiratory muscular paralysis).

RESULTS

Seven randomized controlled studies consisting of 630 patients meeting inclusion criteria were identified. Lipid emulsion helped to improve the cure rate [OR = 2.54, 95% CI (1.33, 4.86), p = 0.005] and lower the mortality rate [OR = 0.31, 95% CI (0.13, 0.74), p = 0.009]. Serum ALT, AST and TBIL in patients undergoing lipid resuscitation were lower than those in the control groups [ALT, SMD = -1.52, 95% CI (-2.64, 0.40), p = 0.008; AST, SMD = -1.66, 95% CI (-3.15, 0.16), p = 0.03; TBIL, SMD = -1.26, 95% CI (-2.32, 0.20), p = 0.02]. Serum AchE level were increased in patients treated with lipid emulsion [SMD = 2.15, 95% CI (1.60, 2.71), p < 0.00001]. Rate of respiratory muscular paralysis was lower in patients undergoing lipid resuscitation than those in the control groups [OR = 0.19, 95% CI (0.05, 0.71), p = 0.01].

CONCLUSION

Based on our meta-analysis of included RCT reports, lipid resuscitation seems likely to help improve prognosis and liver function of OP poisoning patients. However, larger multi-center RCTs are still recommended.

Poisoning with Soman, an Organophosphorus Nerve Agent, Alters Fecal Bacterial Biota and Urine Metabolites: a Case for Novel Signatures for Asymptomatic Nerve Agent Exposure

The experimental pathophysiology of organophosphorus (OP) chemical exposure has been extensively reported. Here, we describe an altered fecal bacterial biota and urine metabolome following intoxication with soman, a lipophilic G class chemical warfare nerve agent. Nonanesthetized Sprague-Dawley male rats were subcutaneously administered soman at 0.8 (subseizurogenic) or 1.0 (seizurogenic) of the 50% lethal dose (LD₅₀) and evaluated for signs of toxicity. Animals were stratified based on seizing activity to evaluate effects of soman exposure on fecal bacterial biota and urine metabolites. Soman exposure reshaped fecal bacterial biota by altering Facklamia, Rhizobium, Bilophila, Enterobacter, and Morganella genera of the Firmicutes and Proteobacteria phyla, some of which are known to hydrolyze OP chemicals. However, analogous changes were not observed in the bacterial biota of the ileum, which remained the same irrespective of dose or seizing status of animals after soman intoxication. However, at 75 days after soman exposure, the bacterial biota stabilized and no differences were observed between groups. Interestingly, in considering just the seizing status of animals, we found that the urine metabolomes were markedly different. Leukotriene C₄, kynurenic acid, 5-hydroxyindoleacetic acid, norepinephrine, and aldosterone were excreted at much higher rates at 72 h in seizing animals, consistent with early multiorgan involvement during soman poisoning. These findings demonstrate the feasibility of using the dysbiosis of fecal bacterial biota in combination with urine metabolome alterations as forensic evidence for presymptomatic OP exposure temporally to enable administration of neuroprotective therapies of the future.IMPORTANCE The paucity of assays to determine physiologically relevant OP exposure presents an opportunity to explore the use of fecal bacteria as sentinels in combination with urine to assess changes in the exposed host. Recent advances in sequencing technologies and computational approaches have enabled researchers to survey large community-level changes of gut bacterial biota and metabolomic changes in various biospecimens. Here, we profiled changes in fecal bacterial biota and urine metabolome following a chemical warfare nerve agent exposure. The significance of this work is a proof of concept that the fecal bacterial biota and urine metabolites are two separate biospecimens rich in surrogate indicators suitable for monitoring OP exposure. The larger value of such an approach is that assays developed on the basis of these observations can be deployed in any setting with moderate clinical chemistry and microbiology capability. This can enable estimation of the affected radius as well as screening, triage, or ruling out of suspected cases of exposures in mass casualty scenarios, transportation accidents involving hazardous materials, refugee movements, humanitarian missions, and training settings when coupled to an established and validated decision tree with clinical features.

The link of organophosphorus pesticides with neurodegenerative and neurodevelopmental diseases based on evidence and mechanisms

Organophosphorus (OP) compounds have been known as the most widely used pesticides during the past half century and there have been a huge body of literature regarding their association with human chronic diseases. Neurodegenerative and neurodevelopmental disorders including Alzheimer, Parkinson, amyotrophic lateral sclerosis (ALS), attention deficit hyperactivity disorder (ADHD), and autism are among the afflicting neurological diseases which overshadow human life and their higher risk in relation to OP exposures have been uncovered by epidemiological studies. In addition, experimental studies exploring the underlying mechanisms have provided some evidence for involvement of cholinergic deficit, oxidative stress, neuro-inflammation, and epigenetic modifications as the processes which are common in the toxicity of the OP and pathophysiology of the mentioned diseases. In addition, genetic mutations and polymorphisms of different variants of some genes like paraoxonase have been shown to be implicated in both susceptibility to OPs toxicity and neurological diseases. In this article, we reviewed the epidemiological as well as experimental studies evidencing the association of exposure to OPs and incidence of neurodegenerative and neurodevelopmental diseases.

Markers of genotoxicity and oxidative stress in farmers exposed to pesticides

The effects of chronic exposure to pesticides can lead to the development of several diseases, including different types of cancer, since the genotoxic and mutagenic capacity of these substances can be observed. The objective of this study is to investigate the relation between the occupational exposure to various pesticides and the presence of DNA damage and oxidative stress. Blood samples from 50 rural workers (41 men and 9 women) exposed to pesticides, 46 controls (20 men and 26 women) from the same city (Antônio Carlos, Santa Catarina state, Brazil) and 29 controls (15 men and 14 women) from another city (Florianópolis, Santa Catarina state, Brazil), were evaluated using the comet assay and the cytokinesis-block micronucleus (CBMN) technique for genetic damage, and the test of thiobarbituric acid reactive substances (TBARS) and catalase (CAT) activity for the oxidative stress. Cholinesterase activities were also determined, but there was no statistical difference among exposed workers and controls. Significant differences were found in DNA damage among groups. The comet assay performed on peripheral blood lymphocytes of these individuals had a significantly higher DNA damage index in the exposed group comparing to controls (p < 0.0001). MNi (p < 0.001), NBUDs (p < 0.005) and NPBs (p < 0.0001) were also found to be significantly higher in the exposed group. The TBARS values were significantly higher comparing to the Florianopolis control group (p < 0.0001). Even though CAT values were higher than controls, there was no statistical difference. Thus, it is concluded that the exposed individuals, participants of this study, are more subject to suffer genetic damage and, consequently, more susceptible to diseases resulting from such damages.

Can we predict intermediate syndrome? A review

INTRODUCTION

Ingestion of organophosphorus insecticides (OPI) is a common method of deliberate self harm in the developing world. Deaths mainly follow as a result of the respiratory failure associated with both cholinergic crisis and the intermediate syndrome. Even though death can be prevented by early mechanical ventilation of these patients, limited studies are available regarding the prediction of intermediate syndrome and subsequent respiratory failure.

OBJECTIVE

To systematically review articles that are published with regard to possible prediction of intermediate syndrome using clinical, biochemical and electrophysiological parameters.

METHODS

A systematic review on literature published in English language was done in the PubMed database without a date limitation. Two sets of search terms were used. The first set consisted of MeSH Terms "organophosphates", "organophosphate poisoning", "op poisoning" "organophosphate insecticide poisoning" and "organophosphorus". The second set included the MeSH Terms "Intermediate syndrome", "proximal muscle weakness", "cranial nerve palsies", "respiratory depression" and "neck muscle weakness". Articles containing at least one word from each set were reviewed.

RESULTS

At least one MeSH term from each set was incorporated in 179 articles. Of these, 69 were rejected as they were not related to organophosphate poisoning or intermediate syndrome.

PREDICTION OF IMS

Clinical prediction is mostly based on ICU scoring systems. Biochemical markers such as reduced levels of serum and erythrocyte acetylcholine esterase have been studied many times. Both clinical and biochemical markers show a modest relationship in predicting IMS. Single fibre electromyography show promising results as it directly assesses neuromuscular junction.

CONCLUSION

The intermediate syndrome which follows organophosphate poisoning still remains a significant problem with its high morbidity. Clinical and biochemical markers show modest results in predicting IMS. Neurophysiological markers such as single fibre EMG should be studied further as they measure activity of affected nicotinic receptors directly.

Prenatal naled and chlorpyrifos exposure is associated with deficits in infant motor function in a cohort of Chinese infants

BACKGROUND

Organophosphate insecticides (OPs) are used worldwide, yet despite nearly ubiquitous exposure in the general population, few have been studied outside the laboratory. Fetal brains undergo rapid growth and development, leaving them susceptible to long-term effects of neurotoxic OPs. The objective here was to investigate the extent to which prenatal exposure to OPs affects infant motor development.

METHODS

30 OPs were measured in umbilical cord blood using gas chromatography tandem mass spectrometry in a cohort of Chinese infants. Motor function was assessed at 6-weeks and 9-months using Peabody Developmental Motor Scales 2nd edition (PDMS-2) (n=199). Outcomes included subtest scores: reflexes, stationary, locomotion, grasping, visual-motor integration (V-M), composite scores: gross (GM), fine (FM), total motor (TM), and standardized motor quotients: gross (GMQ), fine (FMQ), total motor (TMQ).

RESULTS

Naled, methamidophos, trichlorfon, chlorpyrifos, and phorate were detected in ≥10% of samples. Prenatal naled and chlorpyrifos were associated with decreased 9-month motor function. Scores were 0.55, 0.85, and 0.90 points lower per 1ng/mL increase in log-naled, for V-M (p=0.04), FM (p=0.04), and FMQ (p=0.08), respectively. For chlorpyrifos, scores were 0.50, 1.98, 0.80, 1.91, 3.49, 2.71, 6.29, 2.56, 2.04, and 2.59 points lower for exposed versus unexposed infants, for reflexes (p=0.04), locomotion (p=0.02), grasping (p=0.05), V-M (p<0.001), GM (p=0.007), FM (p=0.002), TM (p<0.001), GMQ (p=0.01), FMQ (p=0.07), and TMQ (p=0.008), respectively. Girls appeared to be more sensitive to the negative effects of OPs on 9-month motor function than boys.

CONCLUSIONS

We found deficits in 9-month motor function in infants with prenatal exposure to naled and chlorpyrifos. Naled is being aerially sprayed to combat mosquitoes carrying Zika virus, yet this is the first non-occupational human study of its health effects. Delays in early-motor skill acquisition may be detrimental for downstream development and cognition.

A suspected case of intermediate syndrome in a dog with carbamate toxicosis

CASE REPORT

A 7-year-old female spayed Labrador Retriever was managed for suspected carbamate toxicosis after confirmed ingestion of a large amount of methiocarb. Therapy included decontamination, supportive care and management for aspiration pneumonia. On the third day of hospitalisation, after an initial clinical improvement, the dog developed respiratory muscle weakness, inspiratory dyspnoea and pronounced cervical muscle weakness. These delayed clinical signs were consistent with the 'intermediate syndrome' described in some cases of organophosphate and carbamate toxicoses in humans and also described in one case of organophosphate toxicosis in the dog. Intermediate syndrome has not been reported in carbamate toxicosis in the dog.

CONCLUSION

This case report highlights the necessity for veterinarians to monitor for additional complications not commonly considered in acute carbamate toxicoses.

Delayed Polyneuropathy Induced by Organophosphate Poisoning

An 89-year-old man attempted suicide by ingesting a pesticide (trichlorfon). After surviving the initial critical period in the intensive care unit, he developed rapidly progressive distal weakness and sensory disturbance. Electrophysiological examinations revealed sensory motor axonal polyneuropathy. Delayed polyneuropathy is a rare manifestation of organophosphate poisoning. Nerve conduction studies play an important role in the diagnosis of this rare clinical condition.

Pesticides: an update of human exposure and toxicity

Pesticides are a family of compounds which have brought many benefits to mankind in the agricultural, industrial, and health areas, but their toxicities in both humans and animals have always been a concern. Regardless of acute poisonings which are common for some classes of pesticides like organophosphoruses, the association of chronic and sub-lethal exposure to pesticides with a prevalence of some persistent diseases is going to be a phenomenon to which global attention has been attracted. In this review, incidence of various malignant, neurodegenerative, respiratory, reproductive, developmental, and metabolic diseases in relation to different routes of human exposure to pesticides such as occupational, environmental, residential, parental, maternal, and paternal has been systematically criticized in different categories of pesticide toxicities like carcinogenicity, neurotoxicity, pulmonotoxicity, reproductive toxicity, developmental toxicity, and metabolic toxicity. A huge body of evidence exists on the possible role of pesticide exposures in the elevated incidence of human diseases such as cancers, Alzheimer, Parkinson, amyotrophic lateral sclerosis, asthma, bronchitis, infertility, birth defects, attention deficit hyperactivity disorder, autism, diabetes, and obesity. Most of the disorders are induced by insecticides and herbicides most notably organophosphorus, organochlorines, phenoxyacetic acids, and triazine compounds.

Prenatal exposure to multiple pesticides is associated with auditory brainstem response at 9months in a cohort study of Chinese infants

BACKGROUND

Pesticides are associated with poorer neurodevelopmental outcomes, but little is known about the effects on sensory functioning.

METHODS

Auditory brainstem response (ABR) and pesticide data were available for 27 healthy, full-term 9-month-old infants participating in a larger study of early iron deficiency and neurodevelopment. Cord blood was analyzed by gas chromatography-mass spectrometry for levels of 20 common pesticides. The ABR forward-masking condition consisted of a click stimulus (masker) delivered via ear canal transducers followed by an identical stimulus delayed by 8, 16, or 64 milliseconds (ms). ABR peak latencies were evaluated as a function of masker-stimulus time interval. Shorter wave latencies reflect faster neural conduction, more mature auditory pathways, and greater degree of myelination. Linear regression models were used to evaluate associations between total number of pesticides detected and ABR outcomes. We considered an additive or synergistic effect of poor iron status by stratifying our analysis by newborn ferritin (based on median split).

RESULTS

Infants in the sample were highly exposed to pesticides; a mean of 4.1 pesticides were detected (range 0-9). ABR Wave V latency and central conduction time (CCT) were associated with the number of pesticides detected in cord blood for the 64ms and non-masker conditions. A similar pattern seen for CCT from the 8ms and 16ms conditions, although statistical significance was not reached. Increased pesticide exposure was associated with longer latency. The relation between number of pesticides detected in cord blood and CCT depended on the infant's cord blood ferritin level. Specifically, the relation was present in the lower cord blood ferritin group but not the higher cord blood ferritin group.

CONCLUSIONS

ABR processing was slower in infants with greater prenatal pesticide exposure, indicating impaired neuromaturation. Infants with lower cord blood ferritin appeared to be more sensitive to the effects of prenatal pesticide exposure on ABR latency delay, suggesting an additive or multiplicative effect.

Interrelation of Glycemic Status and Neuropsychiatric Disturbances in Farmers with Organophosphorus Pesticide Toxicity

BACKGROUND

Diverse group of agro-chemicals are indiscriminately sprayed by the farmers for pest control to enhance crop yield. About 25 million agricultural workers in the developing world suffer from at least one episode of poisoning each year, mainly by anticholinesterase- like organophosphates (OPs).

OBJECTIVE

The present study was aimed to establish the OP toxicity in 187 occupationally exposed pesticide sprayers of mango plantation in rural Malihabad, Lucknow, in terms of neuro-cognitive impairment, mental health status, clinical symptoms, diabetes, and hematological factors.

METHOD

The exposed group was compared to 187 pesticides-unexposed normal healthy persons engaged in normal usual agricultural work (age, sex and education corresponding to age group of selected subject group) from Rural Malihabad, Lucknow (India). Neuro-cognitive impairment was measured using the Subjective Neurocognition Inventory and mental health status using the General Health questionnaire-28. The subjects were also tested for biochemical and enzymatic parameters.

RESULTS

The exposed farmers showed alterations in enzymatic and clinical parameters. While the rates of anxiety / insomnia and severe depression were also significantly higher in the pesticide sprayers, disorders affecting psychomotor speed, selective attention, divided attention, verbal memory, nonverbal memory, prospective memory, spatial functioning, and initiative/energy were all lower in the sprayers. Pesticide sprayers showed a number of clinical symptoms like eczema, saliva secretion, fatigue, headache, sweating, abdominal pain, nausea, superior distal muscle weakness, inferior distal muscle weakness, hand tingling and etc. which all significantly correlated with the number of working years.

CONCLUSION

These findings suggested that farmers who work with OPs are prone to neuro-psychological disorders and diabetes.

Clinical and electrodiagnostic findings in cyhalothrine poisoning

Acute onset bulbar symptoms with respiratory failure and descending paralysis may occur in several neuromuscular disorders including variants of Guillain-Barre syndrome (GBS), diphtheria, botulism and toxins. We present a 51-year-old man who presented with complains of ptosis and dyspnea following pyrethroids spraying in an enclosed area for eradication of flea. Within 5-6 days of admission limb weakness, dysphagia, dysarthria, blurred vision, diplopia, tremor and respiratory distress added to previous symptoms. Temporal profile of events after exposure, development of similar symptoms in patient's son, electrodiagnostic findings and exclusion of other etiologies confirms intoxication etiology. We reviewed the literature and provide an extensive electrodiagnostic overview.

Biochemical and molecular evidences on the protection by magnesium oxide nanoparticles of chlorpyrifos-induced apoptosis in human lymphocytes

Background:

Chlorpyrifos (CP) is one of the most widely used organophosphate (OP) insecticides in agricultural and residential pest control with its attendant adverse health effect. In the present study, it is proposed to investigate the possible modulatory role of magnesium oxide nanoparticles (MgO NPs) against CP-induced toxicity in human lymphocytes and determine the mechanisms lying behind this protection by viability and biochemical assays.

Materials and Methods:

Isolated lymphocytes were exposed to 12 μg/mL CP either alone or in combination with different concentrations of MgO NPs (0.1 μg/mL, 1 μg/mL, 10 μg/mL, and 100 μg/mL). After a 3-day incubation, the viability and oxidative stress markers including cellular mitochondrial activity, caspase-3 and -9 activities, total antioxidant power, lipid peroxidation, and myeloperoxidase (MPO) activity were measured. Also, the levels of tumor necrosis factor-α (TNF-α) as inflammatory index, along with acetylcholinesterase (AChE) activity were measured. Statistical differences were determined using one-way analysis of variance (ANOVA) and Dunnett's multiple comparison tests.

Results:

It is indicated that CP-exposed lymphocytes treated with MgO NPs resulted in a substantial reduction in the pace of mortality as well as the stages of oxidative stress in a dose-dependent manner. Also, MgO NPs (100 μg/mL) meaningfully restored CP-induced increase of TNF-α (P < 0.001) and decrease of AChE activity (P < 0.001) and were capable of preventing CP-treated human lymphocytes from apoptosis (P < 0.001).

Conclusion:

Our results demonstrate that MgO NPs in approximate 100 nm diameter not only make cells resistant to the toxic properties of CP but also attenuate toxic effects of CP, which is demonstrating the potential of MgO NPs to be applied in future immune deficiency therapeutic strategies.

Self-regeneration of neuromuscular function following soman and VX poisoning in spinal cord-skeletal muscle cocultures

Aside from nerve agents, various highly toxic pesticides belong to the group of organophosphorus (OP) compounds, thereby causing a large number of intoxications every year. Unfortunately, there are still shortcomings in the current treatment for OP poisoning and research on novel therapeutic options is restricted in several aspects. In this study we investigated the suitability of organotypic cocultures for pharmacological in vitro studies involving OP compounds. These slice cultures are derived from murine spinal cord and muscle tissue forming functional neuromuscular synapses, which trigger spontaneous contractions of muscle fibers. Using video microscopy to quantify muscle activity, we assessed the viability of cocultures after exposure to soman and VX, and the associated loss and recovery of neuromuscular function. Antidotal treatment was not provided. The application of nerve agents led to an almost complete loss of muscle activity. However, cell cultures regained equivalent muscular function to the control situation three and seven days after intoxication. In summary, the tested in vitro system could be a promising tool for the investigation of long term effects and therapeutic options for OP poisoning.

The possible role of intravenous lipid emulsion in the treatment of chemical warfare agent poisoning

Organophosphates (OPs) are cholinesterase inhibitors that lead to a characteristic toxidrome of hypersecretion, miosis, dyspnea, respiratory insufficiency, convulsions and, without proper and early antidotal treatment, death. Most of these compounds are highly lipophilic. Sulfur mustard is a toxic lipophilic alkylating agent, exerting its damage through alkylation of cellular macromolecules (e.g., DNA, proteins) and intense activation of pro-inflammatory pathways. Currently approved antidotes against OPs include the peripheral anticholinergic drug atropine and an oxime that reactivates the inhibited cholinesterase. Benzodiazepines are used to stop organophosphate-induced seizures. Despite these approved drugs, efforts have been made to introduce other medical countermeasures in order to attenuate both the short-term and long-term clinical effects following exposure. Currently, there is no antidote against sulfur mustard poisoning. Intravenous lipid emulsions are used as a source of calories in parenteral nutrition. In recent years, efficacy of lipid emulsions has been shown in the treatment of poisoning by fat-soluble compounds in animal models as well as clinically in humans. In this review we discuss the usefulness of intravenous lipid emulsions as an adjunct to the in-hospital treatment of chemical warfare agent poisoning.

Pesticide poisoning and neurobehavioral function among farm workers in Jiangsu, People's Republic of China

Pesticides remain an integral part of agricultural activities worldwide. Although there have been a number of studies over the last two decades concerning the adverse effects of pesticide poisoning and chronic long term exposures on neurobehavioral function, the impact of recent pesticide poisoning and long term pesticide exposure on neurobehavioral function in Chinese farm workers has not been reported. China is the largest user of pesticides worldwide and figures suggest 53,300-123,000 Chinese people are poisoned every year. A case control study was conducted to examine the impact of recent pesticide poisoning on neurobehavioral function and the relationship between years worked in agriculture and lower performance on neurobehavioral tests. A total of 121 farm workers who self-reported recent pesticide poisonings within the previous 12 months (case group) and 80 farm workers who reported no pesticide poisoning in the previous 12 months (control group) were recruited from three areas of Jiangsu Province, China. The World Health Organization (WHO) recommended neurobehavioral core test battery (NCTB) was used to assess neurobehavioral functioning among cases and controls. Student's t tests and two-way covariance analysis (ANCOVA) were used to test for significant differences in the neurobehavioral test results between the groups. Scores on the Profile of Mood States (POMS) in the recently poisoned group were significantly higher for anger-hostility, depression-dejection, tension-anxiety and lower for vigor-activity compared to controls (p < .05). Digit span, digit symbol, Benton visual retention and pursuit aiming scores were all significantly lower among the recently poisoned group compared to the controls (p < .05). Two-way ANCOVA indicated significantly lower performance in correct pursuit aiming and higher error pursuit aiming amongst the recently poisoned group and those who had worked for more than 30 years in agriculture (p < .05). These findings provide important preliminary epidemiological evidence regarding the association between occupational pesticide exposure and neurobehavioral functioning in Chinese farm workers.