Research progress of organophosphorus pesticides / organophosphorus nerve agents' protein adducts and formation mechanism / 中国药理学通报

Organophosphorus pesticides ( OPP) and organophosphorus nerve agents ( OPNAs) are both toxic organophosphorus compounds, which mainly exert toxic effects through irreversible inhibition of acetylcholinesterase ( AChE).This paper takes protein adducts as the research objective, studying the covalent adducts formed by OPP/OPNAs and different target proteins:endogenous scavengers ( butyrylcholinesterase, albumin, transfer-rin) and low-dose toxicity related proteins ( Cytoskeleton pro- tein, neuropathic target esterase, ubiquitin ) .The formation mechanism of protein adducts and the structural characteristics of active sites are reviewed for providing new ideas to confirm the exposure, trace, and accurate treatment and reasonable prevention of OP poisons in the future.

TRPV4 Regulates Soman-Induced Status Epilepticus and Secondary Brain Injury via NMDA Receptor and NLRP3 Inflammasome / 神经科学通报·英文版

Nerve agents are used in civil wars and terrorist attacks, posing a threat to public safety. Acute exposure to nerve agents such as soman (GD) causes serious brain damage, leading to death due to intense seizures induced by acetylcholinesterase inhibition and neuronal injury resulting from increased excitatory amino-acid levels and neuroinflammation. However, data on the anticonvulsant and neuroprotective efficacies of currently-used countermeasures are limited. Here, we evaluated the potential effects of transient receptor vanilloid 4 (TRPV4) in the treatment of soman-induced status epilepticus (SE) and secondary brain injury. We demonstrated that TRPV4 expression was markedly up-regulated in rat hippocampus after soman-induced seizures. Administration of the TRPV4 antagonist GSK2193874 prior to soman exposure significantly decreased the mortality rate in rats and reduced SE intensity. TRPV4-knockout mice also showed lower incidence of seizures and higher survival rates than wild-type mice following soman exposure. Further in vivo and in vitro experiments demonstrated that blocking TRPV4 prevented NMDA receptor-mediated glutamate excitotoxicity. The protein levels of the NLRP3 inflammasome complex and its downstream cytokines IL-1β and IL-18 increased in soman-exposed rat hippocampus. However, TRPV4 inhibition or deletion markedly reversed the activation of the NLRP3 inflammasome pathway. In conclusion, our study suggests that the blockade of TRPV4 protects against soman exposure and reduces brain injury following SE by decreasing NMDA receptor-mediated excitotoxicity and NLRP3-mediated neuroinflammation. To our knowledge, this is the first study regarding the “dual-switch” function of TRPV4 in the treatment of soman intoxication.

Synthesis of hydrogel polymer coated ZnO nanoparticles and their decontaminating effect against soman in vitro / 中国药理学与毒理学杂志

OBJECTIVE To evaluate the decontamination capability of hydrogel polymer coated ZnO nanoparticles (ZnO NP-gel) against soman. METHODS ZnO NP was synthetized using chemical precipitation method and modified with 4-pentenoic acid,and then polymerized with comonomers to obtain ZnO NP-gel. The transmission electron microscope (TEM), scanning electron microscope (SEM) and particle size instrument were used to observe the internal structure,micromorphology,particle size and zeta potential of these materials. An infrared spectroscope (IR) was used to analyze their chemical bond structure,while X-ray diffraction (XRD) was used to analyze the diffraction pattern.The content of soman was determined by benzidine chromogenic reaction. ZnO NP(1 g·L-1), ZnO NP-gel (1 g·L-1) and distilled water were mixed with soman(52.2 mg·L-1),stood for 30 min,and then filtered before filtrate was subcutaneously injected into mice (40 μL·g-1) to observe the symptoms of poisoning and death. RESULTS SEM and TEM showed that ZnO NP-gel had a block structure, the zeta potential of which was (-7.89 ± 0.04) mV. The results of IR indlicated that ZnO NP-gel had stronger absorption peaks at 754 and 618 cm-1, and XRD revealed that these materials had a sharp peak at 2θ=8.06738°. The decontamination efficiency of ZnO NP-gel was higher than that of ZnO NP group at the same concen?tration (n=3, P<0.05), and the time for decontamination of 50% soman was shortened by four times. The mice were injected subcutaneously with the soman solution treated with ZnO NP-gel, which caused no convulsion or death. CONCLUSION ZnO NP-gel can perform the double function of fast adsorption and catalysis of soman,and the decontamination ability of which could be improved through polymer modification.

Enzimas degradantes de organofosforados: Base molecular e perspectivas para biorremediação enzimática de agroquímicos / Organophosphorus degrading enzymes: Molecular basis and perspectives for enzymatic bioremediation of agrochemicals

RESUMO Muitos compostos organofosforados (OP) são utilizados até hoje na agricultura como pesticidas e, infelizmente, como agentes de guerra química (ou agentes dos nervos) também. Os pesticidas organofosforados e os agentes dos nervos são moléculas extremamente tóxicas, uma vez que atuam como inibidores da enzima Acetilcolinesterase (AChE). O efeito mais preocupante da exposição a estes compostos é a toxicidade colinérgica aguda, ou seja, a perda de coordenação muscular. Uma vez que o indivíduo se contamina, o processo de intoxicação começa através da ligação do OP no sítio ativo da enzima AChE inativando-a. Os tratamentos atuais para pessoas expostas a baixas doses de OP podem ser realizados com atropina, oximas e benzodiazepínicos. Processos de remediação importantes envolvem o emprego de técnicas de biorremediação utilizando diferentes enzimas degradantes, como a Fosfotriesterase da Agrobacterium radiobacter e SMP-30. Devido ao elevado número de intoxicações anualmente, é crucial buscar métodos de tratamento mais potentes e eficazes, e nesta linha, as técnicas envolvendo biorremediação parecem ser bastante promissoras para este propósito.

ABSTRACT Many organophosphorus compounds (OP) are used until today in agriculture as pesticides and, unfortunately, they are used as chemical warfare agents (or nerve agents) as well. Organophosphorus pesticides and nerve agents are extremely toxic molecules, since they act as Acetylcholinesterase (AChE) inhibitors. The most worrying effect of the exposure to these compounds is the acute cholinergic toxicity, which is the loss of muscle coordination. Once one is contaminated, the intoxication process begins through the binding of the OP in the active site of the AChE enzyme inactivating it. Current treatments for people exposed to low doses of OP can be performed with atropine, oximes and benzodiazepines. Important remediation processes involve the employment of bioremediation techniques using different degrading enzymes, such as the Phosphotriesterase from Agrobacterium radiobacter and SMP-30. Due to the high number of intoxications annually, it is crucial to search for more potent and effective treatment methods, and in this line, the techniques involving bioremediation seem to be quite promising for this purpose.

Actualización sobre manejo de araneismo en Perú / Update management on araneism in Peru

La mordedura de araña es un accidente muy común e importante problema de salud pública en lugares con clima tropical y se presenta como un problema muy frecuente en algunas regiones de Latinoamérica. En Perú las especies de araña que presentan más casos de esta problemática son Loxosceles laeta, Latrodectus mactans and Phoneutria spp. El presente trabajo pretende explicar, clarificar y categorizar estas mordeduras de arañas, con el fin de dar a conocerlas para ayudar a que los profesionales de la salud tengan un mayor conocimiento sobre las mismas para un mejor manejo de los casos que se les presenten. (AU)

Spider bites are a common and important public health issue in tropical climates, and become a frequent problem in certain Latin American regions. In Peru, the main species of spiders that represent this problematic are Loxosceles laeta, Latrodectus mactans and Phoneutria spp. The present article intends to explain, clarify and categorize these spider bites, in order to make them known by every health professional to its better management. (AU)

Theme clusters and evolutions of research on medical protection against nerve agents / 军事医学

Objective To find the course of theme evolution for study of medical protection against nerve agents.Meth-ods A method of information visualization based on co-cited analysis was used.The research domain of medical protection against nerve agents was mapped using software VOSviewer.Results There were five research clusters including clinical research, oxime reactivators, detoxification and detection,and bioscavengers.Conclusion Theme evolution is described and research trends are predicted.

Advances in research on oximes as antagonists of nerve agent / 军事医学

Nerve agents (NAs) belong to the class of organic phosphorus compounds which are acetylcholinesterase ( AChE) inhibitors, including soman, sarin, tabun,VX, etc.NAs are extremely toxic and considered as the most danger-ous chemical warfare agents.The current standard treatment for poisoning by nerve agents consists of the combined adminis-tration of anticholinergic drugs such as atropine sulphate, AChE reactivators such as pralidoxime, obidoxime and HI-6 and diazepam for anticonvulsant effects, but oximes are therapeutic antidotes against nerve agent intoxications which exert the therapeutic purposes primarily by reactivating the NAs-inhibited AChE.In this paper, the mechanism of nerve agents, the main working procedure of anti-NAs drugs, the chemical structure of classic reactivator, the corresponding antitoxic action, in vivo and in vitro effects and metabolic kinetics are reviewed.

Reactivation of nanoparticulated HI-6 on acetylcholinesterase activity in soman poisoned mice / 中国药理学与毒理学杂志

OBJECTIVE Based on different drug loading models,three types of nanoparticulated HI-6 were prepared and their reactivations on inhibited acetylcholinesterase (AChE)in peripheral and central nervous syste ms were evaluated and compared in so man-intoxicated mice.METHODS Three kinds of nano-reactivators including HI-6 loaded human serum albunin nanoparticle (HSA-HI-6 NP),HI-6 absorptive mesoporous silica nanoparticle(MSN-HI-6),polylactico-glycolic acid nanoparticle coated HI-6 (PLGA-HI-6 NP)were prepared.The characteristic of all blank nanocarriers was observed through elec-tron microscope.HI-6 release rate of nano-reactivators was also determined in vitro.Then the reactiva-tion rate of nano-reactivators at a constant HI-6 dosage(22 mg·kg -1 )on so man-inhabited AChE both in blood and brain was assessed the so man intoxicated mice(120 μg·kg -1 ,sc).RESULTS All the syn-thetic nanocarriers met the de mand for nanodrug use in vivo.The rate of HI-6 release of nano-reactiva-tors was HI-6 >HSA-HI-6 NPs >MSN-HI-6 >PLGA-HI-6 NP in vitro.On the reactivations of so man-inhibited mice blood AChE,the free HI-6 and HSA-HI-6 NPs,as well as MSN-HI-6 showed co mparable reactivation rates(20% -30%)but were greater than that of PLGA-HI-6 NPs (6.2%)(P <0.01 ). However on the reactivations of so man-inhibited mice brain AChE,the reactivation rate of HSA-HI-6 NP (15.3%)was significantly higher than that of PLGA-HI-6 NP(3.3%)and free HI-6(6.3)(P<0.01 ).In addition,MSN-HI-6 group had a significant reactivation rate compared to PLGA-HI-6 NPs(P <0.01 ). But there was no statistic difference between MSN-HI-6 and free HI-6.CONCLUSION The reactivation potency changed obviously with different drug loading models and HSA-HI-6 NPs had the most potent reactivation on so man-inhibited AChE in both blood and brain.

Development of an automated method for the determination of human paraoxonase1 activity.

Background: Human plasma paraoxonase1 (PON1) is an esterase catalyzing the hydrolysis of organophosphorus pesticides and other xenobiotics. The aims of this study were to develop a rapid method to determinate PON1 activity, evaluate some interference, and study the influence of storage temperature on PON1 activity assay. Methods: Measurement of PON1 activity was performed for 369 samples by measuring the hydrolysis of paraoxon using a spectrophotometric method adapted on konelab 30 . Results: The developed method facilitates the determination of PON1 activity at the rate of more than 200 samples per hour, and it is linear between 2 and 900 IU/L. Intra and inter-assay imprecision coefficients of variation were 2% and 5% respectively. PON1 activity in serum was correlated with those in heparinized plasma (r = 0.994, p < 0.001) and in plasma/EDTA (r = 0.962, p < 0.001). The mean inhibition of the PON1 activity was, by EDTA/K3, 41 ± 10 %. There was not significant PON1 activity variation after 40 days of storage at -20°C or at +4 C. There were no substantial interferences from haemoglobin, jaundice and hyperlipidemia. Conclusion: The developed method is reliable, reproducible, and suitable. It can also be performed on heparinized plasma for the determination of PON1 activity. Hence, it may be useful for assaying PON1 activity in several intoxications such as organophosphorus, sarin, and soman nerve agents.