Clinical characteristics of patients with paraquat mixed with diquat poisoning / 中华急诊医学杂志

Objective:To explore the clinical characteristics of patients with paraquat mixed with diquat poisoning.Methods:The clinical data of 145 patients with paraquat mixed with diquat poisoning admitted to the Department of Emergency of the First Affiliated Hospital of Wenzhou Medical University from January 20, 2016 to March 31, 2022 were retrospectively analyzed. According to the detection results of plasma toxicants in patients with poisoning, the patients were divided into the paraquat diquat mixed group (mixed group), paraquat group (PQ group) and diquat group (DQ group). The clinical indexes, organ dysfunction, different poisoning doses and prognosis of the three groups were compared. Patients in the mixed group were divided into the survival group and death group according to their 90-day survival, and the differences of each index between the two groups were compared. Kaplan-Meier survival analysis was conducted for each index. After Log-rank test, multivariate Cox regression was used to analyze the risk factors of death in the mixed group.Results:A total of 31 patients were included in the mixed group, 92 patients in the PQ group, and 22 patients in the DQ group. There were significant differences in age, toxic dose, number of organ dysfunction, PSS score and APACHE II score among the three groups ( P<0.05). The main injured organs of the mixed group were gastrointestinal tract, kidney, liver, lung and nervous system. The proportion of organ damage in the mixed group was higher than that in the PQ group and DQ group. The white blood cell count, neutrophil count, HB, creatinine, AST, lactic acid, PT and APTT were statistically significant among the three groups ( P<0.05). In the mixed group, patients taking oral administration of < 20 mL all survived; 8 patients taking oral administration of 20 -50 mL died; 11 patients took oral administration of 51-100 mL and 8 (72.7%) died; and 10 patients took oral administration of more than 100 mL and 9 patients (90%) died. In the mixed group, patients with the concentration of diquat > 5000 ng/mL died. Among 31 patients with mixed poisoning, 30 patients (96.78%) had significantly higher concentrations of diquat than paraquat. There were no significant differences in sex, age, time from poisoning to hospitalization, ingestion amount, lymphocyte count, Hb, BNU, CK, total bilirubin, PH, and PT between the survival group and the death group ( P>0.05). Multivariate Cox regression analysis showed that the ingestion amount, plasma PQ concentration at admission, plasma DQ concentration at admission, and lactic acid were independent risk factors for death ( P<0.05). Conclusions:Paraquat mixed with diquat can cause multiple organ function damage. The main damaged organs are gastrointestinal tract, kidney, liver, lung and nervous system. Compared with PQ or DQ poisoning, mixed poisoning has a higher incidence of organ damage, a more serious condition, and a higher mortality rate. Ingestion amount, plasma PQ concentration at admission, plasma DQ concentration at admission and lactic acid were independent factors influencing the prognosis of mixed poisoning.

Clinical value of sodium dithionite reduction method in the diagnosis and treatment of diquat poisoning / 中华急诊医学杂志

Objective:To explore the clinical value of urine semi-quantitative colorimetry by sodium dithionite reduction method in the diagnosis and treatment of diquat poisoning.Methods:The data of 49 patients with acute diquat poisoning treated in the First Affiliated Hospital of Nanjing Medical University from December 3, 2020 to November 23, 2022 were retrospectively analyzed, the correlation between urine colorimetric results and plasma diquat concentration was observed, and the predictive value of urine colorimetric results for target organ damage and prognosis were evaluated.Results:There was a significant correlation between urine colorimetric results and plasma diquat concentration, the correlation coefficient was r=0.89, P <0.01. The cut-off value of urine colorimetry for the predicting the damage of gastrointestinal tract, liver, kidney, and central nervous system injury were 2.5, 3.5, 3.5, 5.5, respectively; in which the urine colorimetric results showed the highest sensitivity in predicting digestive tract injury [ AUC 0.93 (95% CI:0.89-1.00)]. The cut-off value of urine colorimetry for the prognosis of death was 4.5, the positive predictive value was 64.2%, and the negative predictive value was 95.2%. Conclusions:The urine semi-quantitative method can be used for rapid prediction of the plasma diquat concentration range on admission. The urine colorimetry results can also effectively predict the occurrence of organ injury and clinical outcome related to diquat poisoning, which provides evidence for the clinical diagnosis and therapy.

Intoxicação cutânea grave por Paraquat / Serious skin poisoning by Paraquat

O Paraquat é um herbicida não seletivo altamente tóxico, sendo responsável por altas taxas de letalidade acidentais ou provocadas, devido, principalmente, à insuficiência respiratória. Apesar de a intoxicação por via oral ser a principal e mais grave, o contato prolongado com a substância em uma grande área corporal pode gerar uma toxicidade similar e levar ao óbito ­ fato pouco elucidado na literatura. Este é o relato de caso de um homem de 22 anos, que foi admitido em um hospital devido a queixas de mal-estar, náuseas, febre, cefaleia, dor abdominal, diarreia, queimaduras e dispneia. A suspeita diagnóstica inicial foi de hantavirose, leptospirose, dengue e tromboembolismo pulmonar e, posteriormente, foi comprovado intoxicação exógena com agrotóxico por via inalatória e cutânea. Exames de imagem revelaram fibrose pulmonar difusa e ele também apresentou alterações renais, hepáticas e coagulatórias. Como não há antídoto específico, foi empregado tratamento sintomático e suportivo, com uso de carvão ativado, antibióticos, corticoides, antioxidantes e hemodiálise. No entanto, o paciente teve uma piora progressiva do quadro, vindo a óbito devido à síndrome da angústia respiratória aguda e fibrose pulmonar. O Paraquat, embora proibido no Brasil em 2020, continua sendo utilizado de forma ilegal. Além disso, seu substituto, o Diquat, possui toxicidade semelhante. Assim, é fundamental que os profissionais da saúde reconheçam o diagnóstico da intoxicação por tais substâncias e suas diferentes vias de exposição. Também são necessárias novas medidas de fiscalização das substâncias e maior investimento em educação em saúde para evitar exposições acidentais, assim como relatado (AU).

Paraquat is a highly toxic non-selective herbicide and is responsible for high accidental or provoked lethality rates, mainly due to respiratory failure. Although oral poisoning is the primary and most severe, prolonged contact with the substance in a large body area can lead to similar toxicity and death ­ a fact that is little elucidated in the literature. This is the case report of a 22-year-old man admitted to a hospital due to complaints of malaise, nausea, fever, headache, abdominal pain, diarrhea, burns and dyspnea. The initial diagnostic suspicion was hantaviruses, leptospirosis, dengue and pulmonary thromboembolism, and there was subsequently proven exogenous intoxication with pesticides by inhalation and cutaneous route. Imaging tests revealed diffuse pulmonary fibrosis and he also had renal, hepatic and coagulation alterations. As there is no specific antidote, symptomatic and supportive treatment was performed using activated charcoal, antibiotics, corticosteroids, antioxidants and hemodialysis. However, the patient had a progressive worsening of the condition and died due to acute respiratory distress syndrome and pulmonary fibrosis. Paraquat, although banned in Brazil in 2020, continues to be used illegally. In addition, its substitute, the Diquat, has similar toxicity. Thus, it is essential that health professionals recognize the diagnosis of intoxication by such substances and their different exposure routes. New control measures for these substances and greater investment in health education are also needed to prevent accidental exposure, as reported (AU).

A case of delayed peripheral neuropathy caused by diquat poisoning / 中华劳动卫生职业病杂志

Diquat is a kind of conductive contact-killing herbicides. The damage of central nervous system is relatively common, but the peripheral neuropathy caused by diquat has not been reported yet. In September 2021, we treated a patient with diquat poisoning. During the hospitalization, the patient was diagnosed with peripheral neuropathy. Therapy for peripheral nerve injury was given on the basis of conventional treatment of poisoning. The patient was discharged after his condition was stable. The follow-up showed that the peripheral neuropathy of patient was better than before. According to the condition of this patient, it is suggested that we should not only protect the function of gastrointestinal tract, liver, kidney, and central nervous system early, but should also pay attention to the damage of peripheral nervous system in clinical work. We should intervene earlier to improve the prognosis of patients.

Imaging features of 10 patients with toxic encephalopathy caused by diquat / 中华劳动卫生职业病杂志

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.

Analysis of 1 case of convulsion death caused by large dose of diquat poisoning / 中华劳动卫生职业病杂志

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.

Effects and significance of continuous hemoperfusion on patients with diquat poisoning / 中华危重病急救医学

Objective:To investigate the effect of continuous hemoperfusion (HP) on the levels of soluble CD14 isoform (sCD14-st) and neutrophil gelatinase-associated lipocalin (NGAL) on patients with diquat (DQ) poisoning and its significance.Methods:A total of 86 patients with acute DQ poisoning admitted to the department of emergency medicine, Harrison International Peace Hospital Affiliated to Hebei Medical University from May 2018 to August 2021 were enrolled and divided into the intermittent HP group (40 cases) and the continuous HP group (46 cases) according to the random number table method. All patients received basic treatment and continuous veno-venous hemofiltration (CVVH) within 24 hours after admission. On this basis, the intermittent HP group received HP treatment within 2 hours, lasting 2 hours each time for every 8 hours, 3 times in all; the continuous HP group received continued HP treatment until there was no DQ component in urine samples. Serum NGAL levels were detected in all patients before treatment and at 3 hours, 12 hours, 24 hours, 2 days, 3 days, 5 days, and 7 days after treatment. At the same time, serum sCD14-st, blood lactate (Lac), arterial partial pressure of oxygen (PaO 2), serum creatinine (SCr), MB isoenzyme of creatine kinase (CK-MB) and interleukin-18 (IL-18) levels were detected before treatment and at 24 hours, 3 days, and 7 days after treatment. Kaplan-Meier survival curve was drawn to analyze the 28-day survival of patients. Results:Before treatment, there was no significant difference in serum NGAL, sCD14-st, Lac, PaO 2, SCr, CK-MB and IL-18 levels between the two groups. With the prolongation of treatment, the serum levels of NGAL, sCD14-st, Lac, SCr, CK-MB and IL-18 in the intermittent HP group increased at first and then decreased. Serum levels of NGAL, sCD14-st, CK-MB and IL-18 reached their peaks at 24 hours after treatment, and the Lac and SCr levels reached their peaks at 3 days after treatment. In addition, the levels of the above indexes at each time point in the continuous HP group were all significantly lower than those in the intermittent HP group [after 24 hours of treatment: NGAL (μg/L) was 345.90±30.75 vs. 404.24±38.79, sCD14-st (ng/L) was 1 941.88±298.02 vs. 2 656.35±347.93, CK-MB (U/L) was 30.67±9.11 vs. 43.28±8.06, IL-18 (ng/L) was 139.49±16.29 vs. 177.98±27.85; 3 days of treatment: Lac (mmol/L) was 2.98±0.26 vs. 3.72±0.49, SCr (μmol/L) was 125.01±24.24 vs. 156.74±28.88; all P < 0.05]. However, there was no significant difference in PaO 2 levels between the two groups at each time point after treatment. The Kaplan-Meier survival curve showed that the 28-day mortality of patients in the continuous HP group was significantly lower than that in the intermittent HP group [26.09% (12/46) vs. 52.50% (21/40); Log-Rank test: χ2 = 7.288, P = 0.007]. Conclusion:Continuous HP could effectively reduce serum sCD14-st, NGAL levels and 28-day mortality in patients with DQ poisoning, with good curative effect.

Seven cases of toxic encephalopathy associated with diquat poisoning / 中华急诊医学杂志

Objective:To improve the understanding of the clinical features of toxic encephalopathy associated with diquat poisoning.Methods:This study collected and analyzed the diagnosis and treatment process of 7 patients with acute diquat poisoning combined with central nervous system complications admitted to the First Affiliated Hospital of Zhengzhou University from April 2021 to April 2022. "Diquat" and "Poisoning" were used as keywords to search in CNKI, Wanfang database and PubMed database, and the literature of previous cases was reviewed for summary analysis.Results:Among the 7 patients in our hospital, there were 2 males and 5 females, with an average age of 31 years (range14-57) and an average dose of 23.14 g [(10-40)g]. During the treatment, 3 patients developed irritability and convulsions, 3 patients occurred coma, and one had generalized tonic-clonic seizures. Four patients died and 3 survived, of which 2 patients returned to normal life and study, and one remained abnormal mental behavior (currently in long-term follow-up). All three survivors developed neurological symptoms later than those who died, and were awake about 30 days after taking the drug.Conclusions:Toxic encephalopathy associated with diquat poisoning has rapid progression, poor prognosis and high mortality. This study found that the survival rate of patients with > 48 h of first onset of neurological symptoms is much higher than that of patients with ≤ 48 h of first onset of neurological symptoms, while sex, age, estimated oral dose, and type of presentation of neurological symptoms for the first time have little effect on the survival rate of hospital discharge. The earlier neurological symptoms appear, the greater the likelihood of a poor prognosis.

Clinical features of 86 cases of acute diquat poisoning / 中华危重病急救医学

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.

The value of neutrophil gelatinase-associated lipocalin and neutrophil-to-lymphocyte and platelet ratio in the early prediction of kidney injury in elderly patients with Diquat poisoning / 中华老年医学杂志

Objective:To explore the value of neutrophil gelatinase-associated lipocalin(NGAL)and neutrophil-to-lymphocyte and platelet ratio(NLPR)for early prediction of kidney injury with Diquat(DQ)poisoning in elderly patients.Methods:In this retrospective study, a total of 106 elderly patients with DQ poisoning treated in the Emergency Intensive Care Unit(EICU)of Harrison International Peace Hospital Affiliated to Hebei Medical University between October 2019 and October 2021 were divided into an acute kidney injury group(AKI group, n=62)and a non-acute kidney injury group(NAKI group, n=44). Meanwhile, 40 non-elderly patients with DQ poisoning served as the control group.Samples of 5 ml venous blood were collected from patients admitted to the EICU to measure NGAL and NLPR levels and Logistic regression analysis was conducted to analyze independent risk factors for AKI in elderly DQ poisoning patients.The area under the curve(AUC)was calculated via the receiver operating characteristic(ROC)curve, and the value of NGAL and NLPR for early prediction of AKI in elderly patients with DQ poisoning and patient prognosis was assessed.Results:Blood NGAL and NLPR levels in the AKI group were significantly higher than in the NAKI group[(387.1±46.6)μg/L vs.(103.5±18.6)μg/L, (13.5±3.4) vs.(5.3±1.1), t=38.243, 15.608, P<0.001 for both]. Logistic regression analysis results showed that elevated levels of NGAL( OR=1.009, 95% CI: 1.003-1.015, P<0.001)and NLPR( OR=1.263, 95% CI: 1.039-1.536, P<0.001)were risk factors for AKI in elderly patients with DQ poisoning.The areas under the ROC curves of NGAL, NLPR and NGAL+ NLPR for AKI prediction were 0.834, 0.803 and 0.873 respectively.The predictive power of NGAL and NLPR for the death of elderly patients with DQ poisoning was higher than that of creatinine clearance(Ccr). The sensitivity of the combination of the two to predict the risk of death was 0.850, the specificity was 0.828, and the AUC was 0.887. Conclusions:NGAL and NLPR are independent risk factors for the occurrence of AKI in elderly patients with DQ poisoning.Combined detection of NGAL and NLPR improves AKI prediction and prognosis assessment in elderly patients with DQ poisoning.

Establishment and evaluation of acute diquat poisoning model in Wistar rats / 中华劳动卫生职业病杂志

Objective@#To establish the Wistar rat model of acute diquat poisoning and observe the pathological damage of main target organs.@*Methods@#Thirty-six Wistar rats were randomly divided into six groups (n=6) , including one normal saline control group and five treatment groups which were separately given single-dose of intragastric administration at the doses of 46.2 mg/kg, 77.0 mg/kg, 115.5 mg/kg, 231.0 mg/kg and 346.5 mg/kg. The pathological changes of lung, liver and kidney were observed by hematoxylin and eosin (HE) and Masson staining. The optimal dose was determined according to the general situation and pathological changes. Thirty-six Wistar rats were randomly divided into five treatment groups and one normal saline control group. Treatment groups were given single-dose of intragastric administration according to the optimal dose. The rats were sacrificed at 1st, 3rd, 7th, 11th and 14th day after exposed, respectively. The activity of serum glutamic-pyruvic transaminase (ALT) and glutamic-oxalacetic transaminase (AST) were measured by chemical colorimetry. The pathological changes of lung, liver and kidney were observed by HE and Masson staining.@*Results@#According to 14 d survival rate, the toxic symptoms and pathological changes, 115.50 mg/kg was determined the best dose. Given single-dose of intragastric administration at the doses of 115.50 mg/kg, it was found that the serum AST and ALT activity of rats on the first and third day of exposure was significant higher than those in control group. The results of pathological examination exhibited that in 115.50 mg/kg group, the pathological changes of lung, liver and kidney began to appear on the first day of exposure, the pathological changes were the most serious on the third day, and then gradually alleviated. On the 14th day, the alveolar septum was slightly widened, with inflammatory cell infiltration, local alveolar cavity became narrow, atrophy, peripheral alveolar compensation, bronchi and alveolar septum collagen fiber proliferation; The local renal tubular epithelial cells were enlarged and necrotic; the central vein surrounding hepatic cells showed vacuolar degeneration with punctate necrosis.@*Conclusion@#The rat model of acute diquat poisoning can be successfully induced by single-dose of intragastric administration. The condition of wistar rats and the pathological damage of the main target organs could be observed during the whole course of 115.50 mg/kg administration.

Clinical observation of 43 cases of acute poisoning caused by herbicide marked diquat / 中华急诊医学杂志

Objective@#To analyze the relationship between clinical characteristics and prognosis of patients with acute herbicide poisoning marked diquat.@*Methods@#A multi-center, retrospective clinical study of patients with acute diquat poisoning admitted into Emergency Department was conducted from June 2015 to August 2018 in 8 hospitals in Jiangsu Province.@*Results@#A total of 43 patients (22 males and 21 females) were collected and the peak age of poisoning ranged 20-39 years old. The only route of poisoning was ingestion. Among these cases, suicide was the most common cause of poisoningaccounting for 90.70%. In emergency treatment, the constituent ratios of gastric lavage, hemoperfusion and glucocorticoid were 87.50%, 72.50% and 42.50%, respectively. The total mortality increased to 60.00% after follow-up, while the in-hospital mortality was 18.60%. The mortality of patients with toxic dose < 50 mL was 11.11%.@*Conclusions@#The incidence of acute herbicide poisoning with "diquat" as commercial component is gradually increasing. At present, the mortality is very high. Ingestion poisoning dose is the key factor affecting prognosis, and the prognosis of patients with oral dose > 50 mL is poor.

Clinical observation of 43 cases of acute poisoning caused by herbicide marked diquat / 中华急诊医学杂志

Objective To analyze the relationship between clinical characteristics and prognosis of patients with acute herbicide poisoning marked diquat.Methods A multi-center,retrospective clinical study of patients with acute diquat poisoning admitted into Emergency Department was conducted from June 2015 to August 2018 in 8 hospitals in Jiangsu Province.Results A total of 43 patients (22 males and 21 females) were collected and the peak age of poisoning ranged 20-39 years old.The only route of poisoning was ingestion.Among these cases,suicide was the most common cause ofpoisoningaccounting for 90.70％.In emergency treatment,the constituent ratios of gastric lavage,hemoperfusion and glucocorticoid were 87.50％,72.50％ and 42.50％,respectively.The total mortality increased to 60.00％ after follow-up,while the in-hospital mortality was 18.60％.The mortality of patients with toxic dose ＜ 50 mL was 11.11％.Conclusions The incidence of acute herbicide poisoning with "diquat" as commercial component is gradually increasing.At present,the mortality is very high.Ingestion poisoning dose is the key factor affecting prognosis,and the prognosis of patients with oral dose ＞ 50 mL is poor.

The experimental study of diquat on the half-Lethal dose and pothological injuny of related organs in wistor rats / 中华劳动卫生职业病杂志

Objective@#To explore the acute toxicity of Diquat in mice and to calculate the median lethal dose (LD50) of Diquat to rats and observe the pathological changes of tissues and organs in rats with different concentrations of Diquat.@*Methods@#Diquat solution of 50 mg/kg was prepared freshly with 1 000 mg of Diquat and dilute the solution with water to a total of 20 ml. A total of 99 healthy adult male Wistar rats were randomly divided into part one, part two and control groups. In the first part, 36 rats were randomly divided into 4 groups: 100 mg/kg group, 200 mg/kg group, 300 mg/kg group and 400 mg/kg group, which were treated with 100 mg/kg, 200 mg/kg, 300 mg/kg and 400 mg/kg of Diquat solution by gavage, respectively. The death and symptoms of poisoning after intragastric administration were recorded, and the maximum tolerated dose and absolute lethal dose were measured. In the second part, 54 rats were randomly divided into 6 groups: 200 mg/kg group, 220 mg/kg group, 240 mg/kg group, 260 mg/kg、280 mg/kg group and 300 mg/kg group, whichwere treated with 200 mg/kg, 220 mg/kg, 240 mg/kg, 260 mg/kg, 280 mg/kg and 300 mg/kg of Diquat solution by gavage, respectively. The survival of rats in different concentration of Diquat was observed and the LD50 was calculated by Excel processing the formula of Koch's method. The control group were given equal volume water under the same experimental conditions. And moreover, the lungs, kidneys, hearts, livers, and brain tissues were collected and fixed by formaldehyde, embedded by paraffin, and sectioned for histopathological light microscopy.@*Results@#The maximum tolerated dose was 240 mg/kg and the absolute lethal dose was 300 mg/kg. The LD50 of Diquat for Rats was 280.58 mg/kg. The high-dose group had significantly more organ damage than the low-dose group after diquat poisoning.@*Conclusion@#The determination of the half-lethal dose of diquat, at the same time observed multiple organs damaged in rats after the diquat quickly poisoned. Kidneys, lungs and heart might be the main organ which was heavily damaged. With the extension of observation time, the organ damage of rats exposed to small doses gradually stabilized.

Intoxicação por diquat / Diquat intoxication

O paraquat e o diquat são herbicidas de contacto do grupo dos bipiridilos, utilizados largamente para controlo de ervas daninhas. A importância deste grupo de herbicidas reside na sua utilização frequente para fins suicidas e pela inexistência de antídoto ou tratamento médico específico. O envenenamento com diquat é muito menos comum que com o paraquat e por isso existem poucos casos descritos na literatura. A dose letal de ambos é sobreponível, contudo o diquat é considerado menos tóxico devido ao menor dano pulmonar. Por outro lado, o diquat tem efeitos tóxicos graves sobre o sistema nervoso central. Por este motivo os sinais de neurotoxicidade pelo diquat são os mais relevantes e incluem sinais de parkinsonismo. O rim é a principal via excretora do diquat e a necrose tubular aguda é a lesão tipicamente identificada. A sobrevida depende de dois fatores: a concentração da substância no plasma e o tempo após a ingestão. O tratamento centra-se em três pontos essenciais: prevenção da absorção, rápida excreção e modificação dos efeitos tecidulares. A hemoperfusão é mais eficaz na clearance do diquat do que a hemodiálise e a sua utilização nas primeiras 12 horas de intoxicação pode reduzir a mortalidade.

Paraquat and diquat are contact herbicides from bipyridyl group, commonly used in weed control. The importance of this herbicide group is due to its frequent use with suicidal purpose and because there is neither an antidote nor a specific treatment. Poisoning with diquat is much less common that with paraquat, so there are few cases published in literature. The lethal dose of both is similar, however diquat is considered less toxic because it causes less lung damage. On the other side, diquat has severe toxic effects on central nervous system and neurotoxic signs are the more relevant, and include Parkinsonism. The kidney is the main excretory pathway of diquat and acute tubular necrosis is typical. Survival depends on two factors: plasma concentration and time of ingestion. Treatment focus in three key points: preventing absorption, rapid excretion and tissue effects. Hemoperfusion is more effective in diquat clearance than haemodialysis and its use in first 12 hours can reduce mortality.

Efeito da dessecação em estádios fenológicos antecipados na cultura da soja / Effects of early desiccation in phenological phases in soybean

O Estado do Mato Grosso detém a maior área plantada de soja, mas perdas de produtividade vêem ocorrendo nessas áreas, não sendo consideradas as que ocorrem por manejo no momento da dessecação, cujos critérios dependem do conhecimento da cultura. Objetivou-se com este trabalho determinar a perda de produtividade de grãos ocorrida pela dessecação em estádios fenológicos antecipados, em cultivares de soja com diferentes tipos de crescimento, em relação ao tratamento sem dessecação. O experimento foi instalado na safra 2008/2009, no município de Lucas do Rio Verde, em delineamento de blocos casualizados, em esquema fatorial (4x5), representado por quatro cultivares (TMG123 RR, NK7074 RR, P98Y11 e SYN9070 RR) em quatro estádios de dessecação (R6, R6+2DD, R6+4DD e R7), além do tratamento testemunha sem dessecação. As plantas colhidas foram divididas em terço superior (TS) e terço médio e inferior (TMI), debulhadas manualmente e depois determinada a massa de 100 grãos. Concluí-se que os valores de maior massa foram obtidos nas cultivares de crescimento determinado e estes decresceram com a dessecação antecipada, aumentando linearmente com o atraso da dessecação. Existem diferentes respostas para cada cultivar causadas pela dessecação, com perdas de rendimento, sendo o terço superior o mais afetado pela dessecação, causando até 15% de perda de produtividade na cultura.

State of Mato Grosso has the largest soybean area planted, yield losses occurring in these areas, not considering the ones that occur by handling during the desiccation, the criteria adopted depend on the knowledge of the culture. The goal of this study was to determine the loss occurred by desiccation in early stages, when compared with no desiccation in soybean fields. The experiment was installed in 2008/2009 season, in the municipality of Lucas do Rio Verde, in a randomized block design in a (4x5) factorial arrangements, represented by four varieties (TMG123 RR, NK7074 RR, P98Y11 and SYN9070 RR) in four stages desiccation (R6, R6+2DD, R6+4DD and R7), and controls without desiccation. The harvested plants were divided into upper third (TS) and medium and lower third (TMI) and manually threshed and after determined the mass of 100 grains. Concluded that the values of the higher mass were obtained in cultivars of determinate growth habit, and these decreased with early desiccation, and increased linearly with the delay of desiccation. There are different answers for each cultivar caused by desiccation, with yield losses, being the upper third the most affected by desiccation, which can causing up to 15% to loss of crop productivity.

Paraquat: The underestimated lethal pesticide.

Paraquat and diquat are popular herbicides which belong to the bipyridyl group. Paraquat was first synthesized in 1882, but began to be used as a herbicide only since the 1960s. It is available either in granular form or as water soluble concentrate which is an odourless brown liquid. The granular form is available as colourless crystals (dichloride salt) or a yellow solid (bis(methyl sulfate) salt). In India, most of the concentrates of paraquat are available as 10–20% solutions. Paraquat is a rapidly acting herbicide and kills the tissues of green plants mainly by contact action with foliage. Ingestion of paraquat by humans is associated with high mortality, which is a fact that is not widely recognized. Estimated lethal dose is just 10 to 15 ml of the concentrate. Ingestion of 20 to 40 mg of paraquat ion per kg body weight results in death in most cases. It is important to treat all cases of paraquat ingestion as potentially fatal poisonings.

Four Cases of Ocular Injury caused by Gramoxone

Parquat, more commonly used in its commercial name, Gramoxone, is a widely used herbicide for it is inexpensive and effective. It is lethal when ingested accidentally or for the purpose of committing suicide. Having experienced four patients who were injured accidentally in the eye by Gramoxone (herbicide containing paraquat and diquat), we report these cases with the review of the literatures.

In Vitro Adsorption Characteristics of Diquat by Activated Charcoal for Primary Treatment of Acute Poisoning / 日本農村医学会雑誌

For the evaluation on the efficacy of activated charcoal as an antidote in acute diquat poisoning, the adsorption characteristics of diquat in distilled water and in physiological saline solution were investigated.<BR>The amount of diquat adsorbed onto activated charcoal in physiological saline solution was larger than that in distilled water. The enhancing effect of sodium chloride on diquat removal by activated charcoal was observed.<BR>The adsorption rate of diquat onto activated charcoal was also enhanced by the addition of saline. The correlations between the adsorptivity for diquat and properties of activated charcoal were not significant.<BR>These results suggest that the increase of adsorptivity of activated charcoal for diquat might be due to the increase in electrostatic interaction between the surface on which an electrical double layer was formed by saline and diquat.