Curcumin alleviates cecal oxidative injury in diquat-induced broilers by regulating the Nrf2/ARE pathway and microflora

This study evaluated the alleviative effect of curcumin (CUR) on the diquat (DQ)-induced cecal injury in broilers. A total of 320 one-day-old Cobb broilers were selected and randomly divided into 4 treatments, namely control, DQ, CUR 100, and CUR150 groups. The control and DQ groups were fed a basal diet, while the CUR 100 and CUR150 groups were fed the basal diet supplemented with 100 and 150 mg/kg CUR, respectively. Each group had 8 replicates, with 10 broilers per replicate. On day 21 of the experiment, 1 broiler was selected from each replicate and intraperitoneally injected 20 mg/kg body weight of DQ for DQ, CUR 100, and CUR 150 groups. Broilers in control group received equivalent volume of saline. Broilers were euthanized 48h postinjection for tissue sampling. The results showed that DQ injection could cause oxidative stress and inflammatory reactions in the cecum, affecting the fatty acid production and flora structure, thus leading to cecum damage. Compared with the DQ group, the activity of superoxide dismutase, the level of interleukin 10, acetic acid, and total volatile fatty, and the abundance of nuclear factor E2-related factor 2, copper and zinc superoxide dismutase and catalase mRNA in the cecal mucosa of broilers in the CUR group increased significantly (P < 0.05). However, the levels of malondialdehyd, reactive oxygen species, tumor necrosis factor-alpha, and the expression of cysteine-aspartic acid protease-3 and tumor necrosis factor-alpha decreased significantly (P < 0.05) in the CUR group. In addition, CUR treatment alleviated the damage to the cecum and restored the flora structure, and Lactobacillus and Lactobacillaceae promoted the alleviative effect of CUR on DQ. In summary, CUR could alleviate the cecal injury caused by DQ-induced oxidative damage and inflammatory reactions by regulating the Nrf2-ARE signaling pathway and intestinal flora, thus protecting the cecum.

Prognosis prediction of procalcitonin within 24 h for acute diquat poisoning

BACKGROUND

To explore the predictive value of procalcitonin (PCT) within 24 h after poisoning for prognosis of acute diquat poisoning.

METHODS

This retrospective study included acute diquat poisoning patients in the Nanyang City Hospital between May 2017 and July 2021.

RESULTS

Among the 45 patients included, 27 survived. The maximum PCT value within 24 h after poisoning was significantly higher in the non-survival patients [9.65 (2.63, 22.77) vs. 0.15 (0.10, 0.50) µg/mL, P < 0.001] compared to the survival patients. The area under the ROC curve (AUC) indicated that the maximum PCT value within 24 h had a good predictive value (AUC = 0.905, 95% CI: 0.808-1.000) compared to ingested quantity (AUC = 0.879, 95% CI: 0.776-0.981), serum creatinine (AUC = 0.776, 95% CI: 0.640-0.912), or APACHE II score (AUC = 0.778, 95% CI: 0.631-0.925). The predictive value of maximum PCT value within 24 h was comparable with blood lactate (AUC = 0.904, 95%CI: 0.807-1.000).

CONCLUSIONS

The maximum PCT value within 24 h after poisoning might be a good predictor for the prognosis of patients with acute diquat poisoning.

Clinical characteristics of survivors versus non-survivors after acute diquat poisoning: a comparative study

The aim of this study was to compare the clinical characteristics between survivors and non-survivors after acute diquat (DQ) poisoning. Patients treated in the Emergency Department of Fu Yang People's Hospital for DQ poisoning between January 2018 and February 2022 were enrolled in this retrospective comparative study. A total of 65 patients were collected, including 36 males (55.4%) and 29 females (44.6%). There were 34 survivors (52.3%), and 31 non-survivors (47.7%). Patients in the non-survivor group were significantly older (P = 0.003), received a higher dose of DQ before admission (P < 0.001), had more severe organ damage (P < 0.001), lower respiration rate (P < 0.001) and enema (P = 0.009), lower GCS score (P = 0.038), and higher SIRS score (P = 0.018) and APACHE-II score (P < 0.001) than patients in the survivor group. Additionally, biochemical indicators after admission between survivors and non-survivors were significantly different (all P < 0.05). Multivariate logistic regression analysis showed that respiratory failure (P = 0.021), the dose of DQ (P = 0.022), respiratory rate (P = 0.007), and highest alanine transaminase (ALT) level after admission (P = 0.030) were independent risk factors for acute DQ-induced death. These data suggest that non-survivors with acute DQ poisoning are more likely to suffer from respiratory failure, have higher respiratory rate and ALT after admission, and are exposed higher doses of DQ before admission than survivors.

Autophagy mediated FTH1 degradation activates gasdermin E dependent pyroptosis contributing to diquat induced kidney injury

Acute kidney injury (AKI) induced by diquat (DQ) progresses rapidly, leading to high mortality, and there is no specific antidote for this chemical. Our limited knowledge of the pathogenic toxicological mechanisms of DQ has hindered the development of treatments against DQ poisoning. Pyroptosis is a form of programmed cell death and was recently identified as a novel molecular mechanism of drug-induced AKI. To explore the role of pyroptosis in HK-2 cells exposed to DQ, the plasma membrane damage of the cells was detected by LDH release assay. Western blot was performed to detect the cleavage of GSDME. Proteomics analysis was performed to explore the mechanism of DQ induced nephrotoxicity. FerroOrange probe was used to measure the intracellular Fe2+ levels. Herein, we show that DQ induces pyroptosis in HK-2 cells. Mechanistically, DQ induces the accumulation of mitochondrial ROS and initiates the cleavage of gasdermin E (GSDME) in an intrinsic mitochondrial pathway. Knockout of GSDME attenuated DQ-induced cell death. Further analysis revealed that loss of FTH1 induces Fe2+ accumulation, contributing to DQ-induced pyroptosis. Knockdown LC3B could help restore the expression of FTH1 and improve cell viability. Moreover, we found DFO, an iron chelator, could reduce cellular Fe2+ levels and inhibit pyroptosis. Collectively, these findings suggest an unrecognized mechanism for GSDME-dependent pyroptosis in DQ-induced AKI.

Elucidating the mechanisms underlying astrocyte-microglia crosstalk in hippocampal neuroinflammation induced by acute diquat exposure

The transition from paraquat (PQ) to diquat (DQ), both organic dication herbicides, in China has led to significant increases in the number of acute DQ poisoning cases. Case studies have shown that acute DQ poisoning resulted in injury to the central nervous system (CNS), but the mechanism underlying the injury remains to be explored. The present study aimed to investigate how DQ influenced purinergic signaling between astrocytes and microglia and whether extracellular ATP (eATP) was involved in promoting neuroinflammation induced by acute DQ toxicity through the activation of the P2X4/NLRP3 signaling pathway. We constructed a rat model of acute DQ toxicity to observe the pathological changes in hippocampal tissues after DQ exposure and measure the expression levels of IL-1β and TNF-α in the hippocampal tissue. We also established an in vitro co-culture model of C6 astrocytes and BV-2 microglia using transwell chambers, measured the amount of eATP secreted into C6 astrocytes after DQ treatment, and assessed the inflammatory response and changes in the P2X4/NLRP3 signaling pathway in BV-2 microglia. The results showed that the neurons in the hippocampal tissue of rats exhibited loose arrangement, nuclear consolidation, and necrosis after DQ exposure, and IL-1β and TNF-α levels were signification higher in the hippocampal tissue after DQ exposure. DQ exposure to the co-cultured cells induced an increase in ATP secretion from C6 astrocytes as well as a significant increase of P2X4, NLRP3, IL-1β, and IL-18 expression in BV-2 microglia. In contrast, pretreatment of C6 astrocytes with apyrase (an ATP hydrolase) resulted in a significant decrease of P2X4, NLRP3, IL-1β, and IL-18 expression in BV-2 microglia. Furthermore, inhibition of P2X4 expression in BV-2 microglia by transfection with si-P2X4 effectively reversed the increase of NLRP3, IL-1β, and IL-18 in BV-2 microglia induced by DQ when co-cultured with C6 astrocytes. These results indicate that astrocytes can activate the P2X4/NLRP3 signaling pathway in microglia through the DQ-induced extracellular release of ATP to promote neuroinflammation in rat hippocampal tissue.

Mid-to-late stage diquat accumulation in the central nervous system: A severe case of oral poisoning

A 54-year-old woman in good health was admitted to our hospital with diquat poisoning. The patient drank an unknown dose of diquat, and acute kidney injury developed early. However, there were no obvious pulmonary abnormalities and no signs of central nervous system toxicity in the early stage. The woman underwent active treatment, which resulted in a significant decrease in blood diquat levels, but her lung condition progressively worsened and neurological symptoms developed. Fortunately, the patient survived after intensive hemoperfusion combined with continuous renal replacement therapy (CRRT), intracranial pressure reduction, and anti-infective treatment. This case report highlights the importance of being aware of the development of delayed pulmonary symptoms and neurologic complications when caring for patients poisoned with diquat, even in those with low diquat blood concentrations. Interestingly, we also detected the concentration of diquat in the cerebrospinal fluid (CSF) of patients with diquat poisoning, and found that the rate of decrease of diquat concentration in the CSF was considerably slower than that in the blood.Notably, a specific correlation was observed between the concentration of diquat in the CSF, rather than in the blood, and both the intracranial pressure (ICP) and the severity of cerebral edema in this patient.

Simultaneous determination of water-soluble herbicides using hydrophilic interaction liquid chromatography-mass spectrometry

PURPOSE

The analysis of water-soluble herbicides, including glyphosate (Glyp), glufosinate (Gluf), paraquat (PQ), and diquat (DQ), is time-consuming and expensive because they cannot be analyzed using general toxicological screening methods. Thus, this study aimed to develop a simple and rapid method to simultaneously analyze these compounds without any derivatization nor ion-pairing reagents.

METHODS

The analytes were separated using hydrophilic interaction liquid chromatography and detected using tandem mass spectrometry. The developed method was applied to plant and biological samples assuming criminal damage and poisoning cases, respectively.

RESULTS

All analytes were separated well and detected with good peak shapes. For plant samples, the herbicides were specifically detected from withered leaves using a simple extraction method. For biological samples, quantitative analysis was successfully validated, and the limit of quantification values of Glyp and Gluf were 0.2 µg/mL, and those of PQ and DQ were 1 ng/mL.

CONCLUSION

The developed method had sufficient performance for practical forensic applications including poisoning cases and malicious uses to damage commercial crops.

Clinical and pathological characteristics of diquat poisoning-related acute kidney injury

Objectives: Diquat has replaced paraquat in agricultural areas as a herbicide but has led to extensive poisoning. Unlike paraquat, which targets the lungs, diquat primarily targets the kidneys. Autopsies and animal experiments suggest that interstitial kidney damage is the most critical renal lesion. Diquat is a nonselective chemical widely used for terrestrial and aquatic plants after the ban on paraquat. Although diquat is known to affect the kidneys mainly, no study has reported renal biopsy in patients with diquat poisoning.Methods: We investigated the histopathologic feature in a young man with diquat poisoning who developed acute kidney injury by renal biopsy.Results: Autopsy and animal experiments suggest that interstitial kidney inflammation is the most critical renal lesion. Surprisingly, our results showed that lipid degeneration and acute tubular injury with limited interstitial inflammation were the dominant histologic findings in this patient. Conclusions: Based on a renal biopsy, this was the first study describing the characteristics of the kidney affected by diquat poisoning. Our findings might provide information for managing patients who develop AKI due to diquat poisoning.

[A Preliminary Study on the Plasma Metabolomic Profiles of Patients Suffering From Acute Diquat Poisoning]

Objective

To analyze the plasma metabolomic features of patients suffering from acute diquat (DQ) poisoning and to explore the molecular mechanism and potential biomarkers of DQ poisoning.

Methods

A total of 7 patients suffering from acute DQ poisoning were enrolled in the DQ poisoning group. The poisoning of these patients occurred within a 12-h window at the time of enrollment. Meanwhile, 7 healthy immediate family members of the patients were enrolled as the normal controls. Liquid chromatography-mass spectrometry (LC-MS) was used to perform non-targeted metabolomic profiling of the plasma samples and to screen and identify differential metabolites and metabolic pathways.

Results

A total of 104 metabolites were screened and identified (P<0.05 and the variable importance in the projection [VIP]>1). Compared with those of the control group, 61 metabolites, such as sorbitol and galactitol, were up-regulated, and 43 metabolites, such as myo-inositol and gamma-glutamylcysteine, were down-regulated in the DQ poisoning group. Pathway enrichment analysis revealed changes in 11 metabolic pathways, including those for galactose metabolism and linoleic acid metabolism (P<0.05).

Conclusion

Metabolomics analysis of plasma samples from DQ poisoning patients shows that DQ mainly interferes with the metabolism of energy, amino acids, and lipids, thus causing metabolic disorders. Some potential biomarkers closely associated with oxidative stress and organ damage of the liver, kidney, and nervous system have been identified.

Clinical and pathological characteristics of acute kidney injury caused by diquat poisoning

Introduction: Diquat poisoning leads to kidney injury, hepatotoxicity, rhabdomyolysis, gastrointestinal hemorrhage, and respiratory failure. Diquat has high mortality and no specific antidote. The pathology of acute kidney injury caused by diquat poisoning has been mainly investigated in animal studies and autopsies, and typically shows renal tubular necrosis. To our knowledge, antemortem renal biopsy has not been reported in humans.Case reports: Two males and one female presented following deliberate diquat self-poisoning. Their main clinical manifestations were abdominal pain, nausea, and emesis. All developed acute kidney injury. Kidney biopsy was performed in two cases which showed acute tubular necrosis with renal interstitial edema and multifocal inflammatory cell infiltration. Treatments given included gastric lavage, catharsis, early hemoperfusion combined with continuous kidney replacement therapy or hemodialysis, administration of glucocorticoids, and antioxidant therapy. All patients survived.Discussion: Despite potentially lethal ingestions three patients survived oral diquat poisoning with intensive supportive care. No clear relationship can be made between any of the therapies given and patient outcome.Conclusions: Kidney biopsy in these patients confirmed proximal renal tubular injury was the major pathological finding although interstitial injury was also present. The role of therapies that address renal pathology requires further study.

Fluorescence Detecting of Paraquat and Diquat Using Host-Guest Chemistry with a Fluorophore-Pendant Calix[6]arene

Paraquat (PQ) and diquat (DQ), some of the most widely used herbicides in the world, both present a high mortality index after intentional exposure. In this paper, a fluorescence sensing method for PQ and DQ, based on host-guest molecular recognition, is proposed. Calix[6]arene derivatives containing anthracene or naphthalene as pendant fluorophore at their lower rim recognize DQ and PQ in hydroalcoholic solution with a broad linear response range at the μg L^-1 level concentration. The linear response ranges were found from 1.0 to 18 μg L^-1 with the detection limit of 31 ng L^-1 for paraquat, and from 1.0 to 44 μg L^-1 with the detection limit of 0.16 μg L^-1 for diquat. The recognition process is detected by following the decrease in the fluorescence emission consequent to complexation. The proposed quenching method has been applied to the determination of paraquat in drinking water samples.

Constructing a Ring-like Self-Aggregation SERS Sensor with the Coffee Ring Effect for Ultrasensitive Detection and Photocatalytic Degradation of the Herbicides Paraquat and Diquat

A strategy for building ring-like deposit surface-enhanced Raman scattering (SERS) sensors with the coffee ring effect through the functional modification of the silica nanoparticle surface encapsulated by free-tagged Ag nanoparticles is addressed along with their applications in the SERS-based detection and degradation of target species, including paraquat, diquat, and their free radicals. The nanogap formed by two interparticles with SERS hotspots provides a gigantic amplification signal for the Raman scattering intensity of the analyte molecule located approximately at the hotspots. The enhanced Raman spectrum signals of these target analytes were achieved through the hotspot region of the surface plasmon resonance (SPR) located on the embankment formed by self-aggregation of SiO₂@Ag nanoparticles due to the coffee ring effect. Meanwhile, the intrinsic properties of Ag nanoparticles embedded onto the silica surface were applied to photocatalytically degrade the target analytes by harvesting energy from sunlight. The SERS sensor detected the analytes down to 10^-9 M in the aqueous solution.

[The research progress of nervous system damage caused by diquat poisoning]

In recent years, with the withdrawal of paraquat (PQ) pesticides from the market, the number of poisoning cases caused by its substitute diquat (DQ) has shown an increasing trend year by year. Among the clinical manifestations of DQ poisoning, the damage to the central nervous system is relatively common and serious, but the specific toxicity mechanism is not clear, and there is no clear treatment. This article reviews the nervous system damage caused by DQ poisoning in order to improve the understanding systen of DQ poisoning.

Pre-harvest desiccation strategies of soybean culture: a scenario without paraquat

The objective of this study was to evaluate the use of diquat, glufosinate ammonium, saflufenacil and flumioxazim, positioned alone and/or combined, in the pre-harvest desiccation of soybean crops. For this purpose, a field experiment was conducted, with application of the treatments in the phenological stage R 7.2 of soybean. At 3 DAA, the herbicides diquat and their combinations with flumioxazin and ammonium glufosinate, at all doses, resulted in defoliation and desiccation percentages greater than 90%. At 5 DAA, only the flumioxazin and glufosinate ammonium treatments, alone, did not show indices for harvesting. At 10 DAA, only the control differed from the other treatments in relation to desiccation, demonstrating the need to apply desiccants to enable harvest. The results indicate that the combination of herbicides may represent an alternative to reduce doses and increase the efficacy of isolated products through synergism, in addition to operational gains.

[Imaging features of 10 patients with toxic encephalopathy caused by diquat]

Objective: To explore the CT and MRI imaging findings of diquat toxic encephalopathy. Methods: CT and MRI imaging features of 10 patients with diquat poisoning encephalopathy who had been clinically diagnosed were retrospectively reviewed. Results: CT was performed in all 10 patients, and MRI was performed in 8 patients. In 10 patients, 7 had positive signs on CT, and 8 patients with MRI examination had abnormal changes in the images. The main CT findings were symmetrical hypodensity in bilateral cerebellar hemisphere, brainstem, thalamus and basal ganglia, and swelling of brain tissue. The main MRI findings were symmetrical lesions and brain edema in the deep nuclei of cerebellar hemisphere, brainstem, thalamus and basal ganglia, low signal on T1WI, high signal on T2WI and T2-FLAIR, and cytotoxic edema on diffusion weighted imaging (DWI) . On review after treatment, both CT and MRI showed resorption of the lesion, which narrowed in size. Conclusion: The imaging findings of diquat poisoning encephalopathy are characteristic and the location of the lesion is characteristic, and CT and MRI have a certain diagnostic value in diquat poisoning encephalopathy, which is important for clinical treatment.

[Research progress on the relationship between diquat poisoning and nuclear factor E2-related factor 2 signaling pathway]

Since the production and use of paraquat was banned in China in 2016, the use of diquat (DQ) has been increasing and the clinical cases of DQ poisoning have also shown an increasing trend every year. The treatment of DQ poisoning is a worldwide medical problem, and there is no specific antidote. Studies have found that oxidative stress, lipid peroxidation, neurotoxicity, reproductive and developmental toxicity play an important role in DQ poisoning. Nuclear factor E2-related factor 2 (Nrf2) can inhibit oxidative stress, lipid peroxidation and inflammation by regulating the protein expression of upstream and downstream signaling molecules. Therefore, the role of Nrf2 signaling pathway in the poisoning and treatment of DQ has become a hot spot of attention for emergency critical care researchers in recent years. This paper reviews the relationship between Nrf2 signal pathway and DQ poisoning, in order to provide a theoretical basis for improving the treatment strategy for DQ poisoning.

[Clinical features of 86 cases of acute diquat poisoning]

OBJECTIVE

To explore the clinical features of acute diquat (DQ) poisoning, and further improve the awareness of acute DQ poisoning.

METHODS

A retrospective analysis was performed on the clinical data of patients with acute DQ poisoning diagnosed in the emergency department of the Second Hospital of Hebei Medical University from January 1, 2019 to December 31, 2021. The clinical data included age, gender, exposure routes, presence of pesticides (drugs) mixture poisoning, dosage of poison, the time from taking poisoning to admitting in the emergency department, clinical manifestations, laboratory data, treatment, hospital days, prognosis and survival days.

RESULTS

The number of cases who firstly complained of acute DQ poisoning in the past three years were 19 cases in 2019, 28 cases in 2020, and 51 cases in 2021. A total of 12 patients were excluded due to being diagnosed paraquat (PQ) poisoning by toxicology detection. Finally, 86 cases of acute DQ poisoning were included, including 80 cases of oral DQ poisoning, 1 case of intramuscular injection, 1 case of binocular contact and 4 cases of dermal exposure. In 80 cases of oral DQ poisoning, there were 70 cases of diquat poisoning alone (42 cases survived, 28 cases died) and 10 cases of pesticide mixture poisoning (6 cases survived, 4 cases died). The time from oral poisoning to admitting in the emergency department was 0.5-96.0 hours, with an average of (8.6±5.8) hours. The time of intramuscular injection poisoning to admitting in the emergency department was 3 hours. The time of dermal exposure to admitting in the emergency department was relatively long, with an average of 66.1 hours. The time from oral simple DQ poisoning to death was 12.0-108.0 hours, and the time from oral mixed DQ poisoning to death was 24.0-576.0 hours. A total of 70 patients with oral diquat poisoning alone presented various degrees of multiple organ injuries. All patients presented gastrointestinal symptoms such as nausea and vomiting. Renal injury and central nervous system injury were the most significant and closely related to the prognosis.

CONCLUSIONS

Acute oral DQ poisoning can cause to multiple organ injuries, and the clinical manifestations are related to the dose of the poison. In severe cases, acute renal failure and refractory circulatory failure occur within 24 hours after poisoning, and severe central nervous system injury with disturbance of consciousness as the primary manifestation occurs within 36 hours, followed by multiple organ failure until death.

[Analysis of 1 case of convulsion death caused by large dose of diquat poisoning]

A retrospective analysis of a case of death from sudden convulsions caused by oral high-dose diquat was conducted, and the mechanism and treatment of central damage caused by diquat were investigated to lay the foundation for increasing the success rate of treatment of high-dose diquat poisoning. At the same time, at the same time, our clinical treatment experience has also been accumulated.

Ethanol-extraction SERS strategy for highly sensitive detection of poisons in oily matrix

The sensitive detection and identification of toxicants in oily matrices have suffered from difficulty in poisoning incidents, therefore it is necessary to develop the rapid and efficient analytical method to realize the on-site screening and analyzing. In this report, the surface-enhanced Raman spectroscopy (SERS) method was used to detect paraquat and diquat poisons in various oily matrix coupled with solvent extraction. The solvent extraction not only remove interfering impurities of oily substrates, but also can enrich and separate the poisons from oily matrix. It was demonstrated that the ethanol as the extractant was suitable for the rapid separation of poisons such as paraquat (PQ) and diquat (DQ) in oily matrix (soy sauce, pasta sauce, sesame oil, chili oil). Moreover, combined with a handheld Raman spectrometer, the entire detection process was completed within 8 min with the level of 10 ppb PQ and 100 ppb DQ. Furthermore, double-blind experiments verify the reliability of this method. The results demonstrate that this rapid and convenient method could be used for the effective enrichment and sensitive detection of poisons in several oily matrix and has the grate potential application in emergency response and public safety.

Lethal and Teratogenic Impacts of Imazapyr, Diquat Dibromide, and Glufosinate Ammonium Herbicide Formulations Using Frog Embryo Teratogenesis Assay-Xenopus (FETAX)

Globally, amphibians are experiencing widespread abnormalities and population declines. One potential contributor to these challenges is the use of pesticides, particularly aquatic herbicides applied to aquatic habitats inhabited by amphibians. Critical issues of concern are the potential toxicity and teratogenicity of these herbicides towards amphibians. Using the FETAX protocol, three globally used formulations, including diquat dibromide (Midstream), glufosinate ammonium (Basta), and imazapyr (Arsenal), were assessed for embryotoxicity, teratogenicity, and growth inhibition. Developing Xenopus laevis embryos were exposed for 96 h at concentrations of 0.5-3.0 mg/L, 1.6-3.0 mg/L, and 20-45 mg/L for Midstream, Basta, and Arsenal respectively. The 96-h LC₅₀ estimates were 0.83 mg/L acid equivalent (a.e.), 36 mg/L a.e., and 2.2 mg/L a.e., whereas the EC₅₀ estimates were 0.24 mg/L a.e., 28.13 mg/L a.e., and 2.01 mg/L a.e. for the Midstream, Arsenal, and Basta formulations, respectively. These two estimates produced Teratogenic Index of 3.5, 1.3, and 1.1 for Midstream, Arsenal, and Basta, respectively, indicating a high risk of malformation induction by Midstream and moderate risk for Arsenal. Regarding growth inhibition, lowest observable effect concentrations of 0.5 mg/L, 25 mg/L, and 2.0 mg/L were computed for Midstream, Arsenal, and Basta, respectively, producing the minimum concentration inhibiting growth (MCIG) ratios of 0.62, 0.69, and 0.89 for the three formulations. These MICG values are higher than the standard 0.30 growth inhibitors benchmark, suggesting that the formulations are not growth inhibitors at the evaluated concentrations. This study provides evidence of the embryotoxic and teratogenic status of Midstream and the embryotoxicity of Basta. There is a need to further characterise the physiological and ecological impacts of these formulations to ensure responsible use and the safety of amphibians and other wildlife.

Spectroscopic Analysis of the Binding of Paraquat and Diquat Herbicides to Biosubstrates

The study of the interaction of persistent organic pollutants with biosubstrates helps to unravel the pathways for toxicity, however, few mechanistic data are present in the literature for these systems. We analyzed the binding of paraquat (PQ) and diquat (DQ) herbicides to natural calf thymus DNA and a DNA G-quadruplex by spectrophotometric titrations, ethidium bromide exchange tests, viscometry, and melting experiments. The interaction with bovine serum albumin (BSA) protein was studied spectrofluorimetrically at different temperatures. The retention of the targets on positive, negative, and neutral micellar aggregates and liposomes was analyzed by ultrafiltration experiments. Despite some favorable features, PQ and DQ only externally bind natural DNA and do not interact with DNA oligonucleotides. Both herbicides bind bovine serum albumin (BSA). PQ binds BSA mainly according to an electrostatics-driven process. However, ultrafiltration data also show that some hydrophobic contribution participates in the features of these systems. The practical problems related to unfavorable spectroscopic signals and inner filter effects are also discussed. Overall, both herbicides show a low affinity for nucleic acids and weak penetration into liposomes; in addition, the equilibrium constants values found for BSA system suggest optimal conditions for transport in the body.

Dermal absorption of diquat and potential occupational risk

OBJECTIVE

The aim: The toxicological-hygienic assessment of dermal absorption of diquat in terms of potential risk of its bioavailability in professional use.

PATIENTS AND METHODS

Materials and methods: The object of the study was cutaneous exposure of diquat, determined in toxicological experiments of different duration (data of scientific literature) and at the stage of state testing of pesticide preparations based on diquat dibromide (data of a full-scale hygiene experiment, prognostic model of risk assessment), the technical concentrate of diquat dibromide (active substance content not less than 377 g / kg) contains relevant supplements, the content of which is regulated by the Food and Agriculture Organization.

RESULTS

Results and conclusions: Due to the high risk of the diquat adverse effects affecting the personnel, general public and environment, the European Union has introduced administrative decisions to forbid plant protection products containing the diquat. Fulfillment of the conditions of the Association Agreement between Ukraine and the European Union indicates the need to develop common regulations and risk assessment methods aimed at ensuring high level of protection of human health and the environment.

Diquat Determines a Deregulation of lncRNA and mRNA Expression in the Liver of Postweaned Piglets

Oxidative stress is detrimental to animals and can depress the growth performance and regulate the gene expression of animals. However, it remains unclear how oxidative stress regulates the expression of long noncoding RNAs (lncRNAs) and mRNAs. Therefore, the purpose of this article was to explore the profiles of lncRNAs and mRNAs in the liver of piglets under oxidative stress. Here, we constructed a piglet oxidative stress model induced by diquat and evaluated the effects of oxidative stress on the growth performance and antioxidant enzyme activity of piglets. We also used RNA-Seq to examine the global expression of lncRNAs and mRNAs in piglets under oxidative stress. The targets of lncRNAs and mRNAs were enriched in gene ontology (GO) terms and signaling pathways. The results show that the growth performance and activities of antioxidant enzymes were decreased in piglets under oxidative stress. Moreover, eight lncRNAs (6 upregulated and 2 downregulated) and 30 mRNAs (8 upregulated and 22 downregulated) were differentially expressed in the oxidative stress group of piglets compared to the negative control group. According to biological processes in enriched GO terms, the oxoacid metabolic process, intramolecular oxidoreductase activity, and oxidation-reduction process play important roles in oxidative stress. Pathway analysis showed that the signaling pathways involved in insulin and glucose metabolism had a close relationship with oxidative stress. Further in vitro experiments showed that the expression of the upregulated gene GNMT was significantly increased in primary porcine hepatocytes after diquat stimulation. In contrast, the level of the downregulated gene GCK was significantly decreased at 12 h in primary porcine hepatocytes after diquat stimulation. Our results expand our knowledge of the lncRNAs and mRNAs transcribed in the livers of piglets under oxidative stress and provide a basis for future research on the molecular mechanisms mediating oxidative stress and tissue damage.

Polyurethane foam loaded with sodium dodecylsulfate for the extraction of 'quat' pesticides from aqueous medium: Optimization of loading conditions

The cationic herbicides paraquat, diquat and difenzoquat are largely used in different cultures worldwide. With this, there is an intrinsic risk of environmental contamination when these herbicides achieve natural waters. The goal of this work was to propose a novel and low-cost sorbent for the removal of the cited herbicides from aqueous medium. The proposed sorbent was prepared by loading polyurethane foam with sodium dodecylsulfate. The influence of several parameters (SDS concentration, HCl concentration and shaking time) on the loading process was investigated. The results obtained in this work demonstrated that all studied variables influenced the loading process, having significant effect on the extraction efficiency of the resulted PUF-SDS. At optimized conditions, the PUF was loaded by shaking 200mg of crushed foam with 200mL of a solution containing 5.0×10(-3)molL(-1) SDS and 0.25molL(-1) HCl, for 30min. The obtained PUF-SDS was efficient for removing the three herbicides from aqueous medium, achieving extraction percentages higher than 90%. The sorption process followed a pseudo second-order kinetics, which presented excellent predictive capacity of the amount of herbicide retained with time.

Effect of He-Ne laser treatment on the level of lipid peroxidation products in experimental cataract of rabbit eyes

The effect of low-intensity laser irradiation on the processes of lipid peroxidation in lens homogenate and aqueous humor during experimental diquat-induced cataract of rabbit eyes was studied. The levels of primary and secondary products of lipid peroxidation (LPO), conjugated dienes and thiobarbituric acid reactive substances (TBARS), were evaluated. We found that the experimental cataract model leads to a significant increase in the content of conjugated dienes and in the content of TBARS both in lens homogenate and in aqueous humor. The data obtained support the important role of oxidative stress in the development of the diquat-induced cataract model. Low-intensity laser treatment does not provoke a significant decrease in conjugated dienes or in TBARS in either lens homogenate or aqueous humor. Although our therapeutic scheme led to a slightly decreased level of LPO products, we conclude that the effect of low-intensity laser-irradiation may depend on the dose applied, individual tissues and other factors.

[Use of the herbicide diquat for the control of the aquatic plant Pistia stratiotes and its importance in the control of mosquitoes (Diptera: Culicidae)]

The feasibility of the use of the Diquat herbicide (reglone) in the control of the Pistia stratiotes aquatic plant is tested. This facilitates the reduction of mosquito larva densities by the action of natural enemies present in the ecosystem. The associated fauna is not affected by the employed concentrations of the herbicide under these conditions.

[Gas chromatographic analysis of reduction products of paraquat, diquat and the related compounds: reductive cleavage in the pyridine ring on N-alkylpyridinium derivatives with NaBH4-NiCl2 reduction system, and inhibition of the cleavage]

When N-alkylpyridinium derivatives were reduced with sodium borohydride-nickel (II) chloride reduction system, reductive cleavage occurred at the C-N bond in the pyridine ring of N-alkylpyridinium derivatives to give a small amount of reductive cleavage product along with the major perhydrogenated product. It was presumed in the previous report that this reductive cleavage in the pyridine ring proceeded through a complex of nickel ion and 1,2,3,6-tetrahydropyridine derivatives produced with NaBH4 alone reduction. The abundances of these reductive cleavage products arising from N-alkylpyridinium derivatives, i.e., paraquat, diquat and so on, are capable of giving a bad effect on the accuracy of gas chromatographic analysis. For the purpose of inhibition of the reductive cleavage in this reduction system, a suitable catalyst was examined. In addition, we pursued whether borane-1,2,3,6-tetrahydropyridine derivative complexes arose from N-alkylpyridinium derivatives by NaBH4 alone reduction or not, and whether these borane-amine complexes were the precursors of reductive cleavage products or not. N-Alkyl-1,2,3,6-tetrahydropyridine derivatives (III-I, IV-I, VI-I, VII-I and VIII-I) and the corresponding borane-amine complexes (III-II, IV-II, VI-II, VII-II and VIII-II) were synthesized by NaBH4 reduction in aqueous solution of N-alkylpyridinium salts, i.e. I, II, 1,4-dimethylpyridinium iodide (III), 1-dodecylpyridinium chloride (IV), 1,1'-diethyl-4,4'-dipyridinium dichloride (V), 1-methyl-4-phenylpyridinium iodide (VI), 1-n-propylpyridinium iodide (VII) and 1-n-butylpyridinium iodide (VIII). The structure of the borane-amine complexes were proved by the Mass spectrometry and 1H- and 13C-NMR analysis. The NiCl2-NaBH4 reduction of the borane-amine complexes gave the perhydrogenated products alone, but not reductive cleavage products. In conclusion, it was recognized that the precursors of reductive cleavage products were not borane-amine complexes, but 1,2,3,6-tetrahydropyridine. Furthermore, it was found the reductive cleavage at the C-N bond in the pyridine ring of these 1,2,3,6-tetrahydropyridine derivatives was hindered by applying Amberlite-Ni2B, NaBH4 reduction system.

Pathogenesis of diquat-induced liver necrosis in selenium-deficient rats: assessment of the roles of lipid peroxidation and selenoprotein P

A dose of diquat below the amount injurious to selenium-replete animals causes lipid peroxidation and massive liver necrosis in selenium-deficient rats. The current study was undertaken to characterize the lipid peroxidation with respect to the liver injury and to correlate the presence of several selenoproteins with the protective effect of selenium. Lipid peroxidation was assessed by measurement of F2 isoprostanes. Diquat caused an increase in liver and plasma F2 isoprotanes. A gradient of these compounds was detected across the liver in some animals, indicating that this organ was a source of some of the plasma F2 isoprostanes. A time-course experiment showed that liver F2 isoprostane concentration increased before plasma alanine transaminase (ALT) levels rose. Selenium-deficient rats were injected with selenium doses from 2 to 50 micrograms/kg and studied 12 hours later. A dose of 10 micrograms/kg or more prevented diquat-induced lipid peroxidation and liver injury. This dose increased plasma selenoprotein P substantially, and a dose-response was present. Liver cellular and plasma glutathione peroxidase activities remained below 2% of their values in control rats for all selenium doses. In selenium-deficient rats given diquat, hepatic lipid peroxidation precedes hepatic necrosis and could therefore be an important mechanism of the necrosis. Selenoprotein P levels were increased by selenium injections, which protected against diquat injury, but glutathione peroxidase activity was not increased. This is consistent with selenoprotein P being the mediator of the selenium effect.

Antioxidant and anticataractogenic effects of topical captopril in diquat-induced cataract in rabbits

1-[(2s)-3-Mercapto-2-methylpropionyl]-L-proline (captopril), an antihypertensive and free radical scavenger, protected the rabbit lens from peroxidative and oxidative damage induced by 1 mM diquat in vitro. To evaluate the anticataract efficacy of captopril, an experimental group of five rabbits was treated with topical captopril (1% in 0.15 M NaCl, w/v), and 50 microliters was instilled onto both eyes four times a day for a total of 8 weeks. Following the same procedure, the eyes of five rabbits were treated with topical 0.15 M NaCl as a control for captopril treatment. At the end of the first week of treatment, a single intravitreal dose of 120 nmole diquat in 30 microliters of 0.15 M NaCl was injected into the right eye of each rabbit of both the groups. As a control for intravitreal diquat injection, the left eye of all the rabbits were injected with the diluent, 30 microliters per eye. The intravitreal diquat or its diluent injection was only for one time. From slit-lamp biomicroscopic observation of the diquat-injected right eyes, the anticataract effect of captopril in the treatment group was indicated by the finding that in four of five rabbits the cataract did not advance; whereas in four of five rabbits treated with the diluent the cataract progressed to grade 3. The lenses in the diluent-injected control left eyes of the rabbits treated with the captopril or diluent were normal. However, since the number of animals used for the in vivo studies was few, further confirmation of the anticataract effect of captopril is necessary. In diquat-injected right eyes of animals treated with captopril, the integrated rate of O2- production was about 50% less (p less than .001) in the aqueous humor, vitreous humor, and lens, compared with O2-, 33.49 +/- 2.26 microM (mean +/- SEM) in the aqueous humor, 17.12 +/- 0.75 microM in the vitreous humor, and 31.44 +/- 1.29 nmole/g wet weight in the lens of the diquat-injected right eyes treated with the diluent. Similar significant (p less than .01) differences in the production of .OH and H2O2 in eye tissues were also observed.(ABSTRACT TRUNCATED AT 400 WORDS)

An electrophysiological study of ganglion blockade by paraquat and diquat

1. The bipyridilium herbicides, particularly paraquat, have chemical and toxicological features in common with the bi-quaternary ammonium ganglion blockers. 2. Paraquat and diquat were tested for ganglion blocking activity. Rabbit cervical ganglia were superfused with both agents and subsequently with hexamethonium to confirm susceptibility to ganglion blockade. 3. No evidence for ganglion blockade was found at either supra maximal or sub maximal stimulation, and none following repetitive stimulation. 4. The similarities and differences between the bipyridyl herbicides and bi-quaternary ganglion blockers can be explained on the basis of their structures. 5. It is concluded that neither paraquat nor diquat have significant ganglion blocking activity.