Paraquat-induced convulsion and death: a report of five cases

Comparison of Biochemical Parameters between Mouse Model and Human after Paraquat Poisoning

Background. This study was designed to investigate differences in biochemical parameters between mouse and humans after paraquat (PQ) poisoning and develop a suitable animal model for studying organ damage after PQ poisoning. The prognostic factors of PQ-poisoned patients were further analyzed. Methods. Thirty C57BL/6J mice were randomly divided into five groups (control, sham, and 3 PQ doses), and the mouse model was established by intragastric administration of PQ. Physiological indexes such as the body weight, mental state, and mortality rate were observed. Biochemical parameters were analyzed 24 h after PQ poisoning. We also performed a retrospective analysis of clinical data from 29 patients with PQ poisoning admitted to the Emergency Department of the Affiliated Hospital of Taishan Medical College between April 2016 and February 2018. Biochemical parameters were compared between the mouse model and patients with PQ poisoning. Results. In the PQ poisoning mouse model, the lethal dose group PQ360 showed remarkable increases in serum levels of potassium (K+), carbon dioxide (CO2), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) compared with the nonlethal dose PQ100 and PQ200 groups. The biochemical results of the patients showed that K+ and Cl- levels were significantly reduced in the death group compared to the survival group. Levels of ALT, AST, blood urea nitrogen (BUN), and amylase were higher, and the neutrophil-to-lymphocyte ratio (NLR) was increased in the death group compared with the survival group. Conclusions. The combination of age, PQ dosage, K+, Cl-, BUN, ALT, AST, amylase, and NLR can be used to more accurately predict the outcome of patients with PQ poisoning. C57 mice are an appropriate animal model to study liver and kidney functions following PQ exposure.

Injection of Paraquat in the Neck: A Rare Complicated Case Report

Paraquat is a highly toxic compound and a widely used herbicide that causes serious morbidity and mortality. The most well-known route of poisoning is oral ingestion, whereas parenteral injection of paraquat is individually uncommon. We present a case who injected paraquat in his neck in an attempt to commit suicide. His general condition got worsened gradually over 3 days. He received early hemodialysis in 4 h after self-injection and then supportive treatment in intensive care unit. Early hemodialysis helped him survive, but during hospitalization, some rare complications occurred, and unfortunately, he died after 3 months. Despite the high-risk route of poisoning, the patient survived for 3 months. Our patient was protected from renal and hepatic damage may be because of early hemodialysis but suffered from central nervous system and pulmonary damage.

Delayed death following paraquat poisoning: three case reports and a literature review

Paraquat (PQ) poisoning is principally reported in developing countries. However, most fatalities occur elsewhere due to the induction of multi-organ failure. PQ poisoning can hardly be managed by clinical practice, and no specific antidote has come into existence yet. Here three cases, including 17-, 20-, and 23-year-old men, who were poisoned with PQ, have been reported. Furthermore, the literature regarding biological mechanisms, clinical manifestation, and treatment of PQ-induced toxicity was reviewed. Patients who, either intentionally or accidentally, ingested PQ earlier were initially found to be stable at the emergency department (ED). Therefore, they were discharged from the hospital under a follow-up. However, after several days, the patients were referred to the hospital for the second time and despite cardiovascular resuscitation (CPR) efforts, they suddenly expired. The delayed death following exposure to PQ was reported for inducing gradual progressive pulmonary fibrosis, metabolic acidosis, neurotoxicity, renal failure, and liver injury in poisoned patients. Therefore, PQ-intoxicated patients should be supervised for up to several weeks, and kept in the hospital for a longer period of time. Clinical manifestations and laboratory findings are beneficial markers that act as useful predictors of PQ poisoning.

Delivery of a protein transduction domain-mediated Prdx6 protein ameliorates oxidative stress-induced injury in human and mouse neuronal cells

Oxidative stress or reduced expression of naturally occurring antioxidants during aging has been identified as a major culprit in neuronal cell/tissue degeneration. Peroxiredoxin (Prdx) 6, a protective protein with GSH peroxidase and acidic calcium-independent phospholipase A2 activities, acts as a rheostat in regulating cellular physiology by clearing reactive oxygen species (ROS) and thereby optimizing gene regulation. We found that under stress, the neuronal cells displayed reduced expression of Prdx6 protein and mRNA with increased levels of ROS, and the cells subsequently underwent apoptosis. Using Prdx6 fused to TAT transduction domain, we showed evidence that Prdx6 was internalized in human brain cortical neuronal cells, HCN-2, and mouse hippocampal cells, HT22. The cells transduced with Prdx6 conferred resistance against the oxidative stress inducers paraquat, H2O2, and glutamate. Furthermore, Prdx6 delivery ameliorated damage to neuronal cells by optimizing ROS levels and overstimulation of NF-κB. Intriguingly, transduction of Prdx6 increased the expression of endogenous Prdx6, suggesting that protection against oxidative stress was mediated by both extrinsic and intrinsic Prdx6. The results demonstrate that Prdx6 expression is critical to protecting oxidative stress-evoked neuronal cell death. We propose that local or systemic application of Prdx6 can be an effective means of delaying/postponing neuronal degeneration.

The significance of serum uric acid level in humans with acute paraquat poisoning

Hyperuricemia is a strong and independent predictor of all-cause mortality in cardiovascular disease and has been found to play a role in diseases exacerbated by oxidative stress and inflammation. This study aimed to evaluate whether serum uric acid (UA) level is an indicator of outcome in patients with acute paraquat poisoning. A total of 205 subjects who had attempted suicide by oral ingestion of paraquat were admitted to the emergency room between January 2009 and June 2014. Initial serum UA level and other laboratory parameters were measured. A total of 66 patients died during the 30 days after admission, corresponding to a 32.2% cumulative incidence of mortality. UA levels were higher in non-survivors than survivors (P < 0.001) and 30-day mortality increased with increasing baseline serum UA level (P < 0.001). In a prediction analysis for 30-day mortality, the serum UA level had a cut-off concentration of 284 µmol/L in female patients and 352 µmol/L in male patients. Multivariate Cox proportional hazards regression analyses showed that white blood cell counts and UA were independent prognostic factors. In conclusion, we showed that serum UA may be an independent predictor of 30-day mortality in patients with paraquat poisoning.

Clinical characteristics of paraquat poisoning in 22 Chinese children

OBJECTIVE

To retrospectively analyze the clinical characteristics and experience of Chinese children with paraquat poisoning.

METHODS

Twenty-two children with paraquat poisoning who presented to the hospital from October 2007 through September 2012 were enrolled into this study. The clinical indices of these cases were collected and analyzed.

RESULTS

All the children were poisoned due to oral ingestion of paraquat. Different degrees of damage were found in multiple systems in their bodies. All of them were administered pulse therapy using methylprednisolone (20 mg/kg/d × 3d) and Gamma globulin (total 2 g/kg divided into 3 d to 5 d) in the early stage. Prednisone was then given orally for 4 wk to 8 wk. The total mortality rate of the patients was 63.6 % (14 of 22 patients died). Statistical differences (P < 0.05) were found between the surviving and dead patients, with regard to age, plasma paraquat levels, the highest levels of alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transferase, total bilirubin, direct bilirubin, indirect bilirubin, blood urea nitrogen, creatinine and pH value, the lowest levels of PaO2, PaCO2 and SaO2. Plasma paraquat level was positively related to pH value, but was negatively related to PaO2, PaCO2 and SaO2 levels. None of the patients died from hepatic and renal complications. Pulmonary fibrosis was the most severe complication and the primary cause of death.

CONCLUSIONS

Paraquat poisoning is difficult to cure. In this study, pulmonary fibrosis was the primary cause of death. Treatment by administering large doses of glucocorticoids and Gamma globulin proved to be effective in the early stage. However, the treatment may not reverse the development of pulmonary fibrosis. The long-term prognosis of paraquat poisoning was not optimistic. The plasma paraquat level could be a significant factor in predicting the prognosis.

Viologen-phosphorus dendrimers exhibit minor toxicity against a murine neuroblastoma cell line

Dendrimers containing viologen (derivatives of 4,4′-bipyridyl) units in their structure have been demonstrated to exhibit antiviral activity against human immunodeficiency virus (HIV-1). It has also recently been revealed that novel dendrimers with both viologen units and phosphorus groups in their structure show different antimicrobial, cytotoxic and hemotoxic properties, and have the ability to influence the activity of cholinesterases and to inhibit α-synuclein fibrillation. Since the influence of viologen-phosphorus structures on basic cellular processes had not been investigated, we examined the impact of such macromolecules on the murine neuroblastoma cell line (N2a). We selected three water-soluble viologen-phosphorus (VPD) dendrimers, which differ in their core structure, number of viologen units and number and type of surface groups, and analyzed several aspects of the cellular response. These included cell viability, generation of reactive oxygen species (ROS), alterations in mitochondrial activity, morphological modifications, and the induction of apoptosis and necrosis. The MTT assay results suggest that all of the tested dendrimers are only slightly cytotoxic. Although some changes in ROS formation and mitochondrial function were detected, the three compounds did not induce apoptosis or necrosis. In light of these results, we can assume that the tested VPD are relatively safe for mouse neuroblastoma cells. Although more research on their safety is needed, VPD seem to be promising nanoparticles for further biomedical investigation.