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Survival and recovery from nerve agent poisoning requires a continuum of medical care, starting with a rapid initial response followed by continued support though the medical chain. In a military context, research into countermeasures to nerve agent poisoning has traditionally focussed on first-aid, pretreatment and prophylaxis; however, there are many opportunities to optimise the management of nerve agent-poisoned casualties. We have previously demonstrated the efficacy of bioscavenger as a post-exposure, pre-symptomatic therapy in guinea-pigs poisoned by VX via the dermal route. Data will be presented on the efficacy of bioscavenger before, on and after the appearance of signs of poisoning and the influence of introducing a delay between initial treatment and the administration of bioscavenger. Treatment regimens including bioscavenger offered near-complete protection against the VX challenge, in the absence of continuing supportive therapy. The potential for bioscavenger use within the treatment chain could range from pre-exposure to hospital use. Inclusion of bioscavenger has potential to reduce the level of medical care, monitoring and therapeutic intervention for casualties that have been poisoned percutaneously. The results will be discussed in the context of the UK military medical management chain and the considerations and constraints of the operational environment.

This review provides information about blistering chemical warfare agents. The main focus lies on the sulfur mustard. The article summarizes the history of this agent from its discovery to the present, physicochemical properties, toxicokinetics, and the clinical picture of acute intoxication. Late effects of poisoning are discussed as well. The laboratory diagnosis of sulfur mustard exposure is an issue that is currently being discussed by many research groups worldwide. Current therapeutic approaches recommended by NATO are aimed at rapid decontamination and symptomatic treatment. In spite of all efforts, no potent and usable antidote has been found to prevent the devastating outcomes of the exposure. Therefore, efficient protection against sulfur mustard still consists of preventing the contact with organism.

Background: The occurrence of retroperitoneal bleeding and the manner of detection was retrospectively evaluated in patients with life-threatening traumatic bleeding.Methods: The cohort included patients who died in the Trauma Centre of the University Hospital Hradec Kralove in Czech Republic between 2008 and 2012 due to traumatic hemorrhagic shock. Findings of retroperitoneal bleeding and the findings found for life (i.e., CT, FAST, pre-operative findings) were compared.Results: During the five-year period, deaths due to the post-mortem diagnosis of traumatic hemorrhagic shock were recorded in 75 patients, 26 of which (35%) were verified by post-mortem autopsy to have hemodynamically significant bleeding into the retroperitoneum (HSBR) from 31 sources. HSBR was identified for life in 10 patients with HSBR (38.5%). Sensitivity was 55% in CT angiography and 36% in laparotomy without previous CT. The sensitivity of laparotomy with surgical exploration of the retroperi-toneum was 67%. A predisposing factor for hemodynamically significant bleeding into the retroperitoneum, which may escape the surgeon’s attention, is high-energy blunt trauma to the trunk.Conclusions: In the acute stage of treatment of patients with life-threatening bleeding due to high-energy blunt trauma, the surgeon has to decide whether the patient’s condition allows CT and whether hematoma of the retroperitoneum should be revised surgically. However, in the present cohort few patients with HSBR underwent surgical exploration of the retroperitoneum because the hematoma was ascribed to the known injury of the pelvis and spine.Level of evidence: Prognostic study, level III

The Ebola outbreak in West Africa was the 25^th known epidemic of this highly dangerous viral agent since its first capture in 1976. The former Soviet Union explored the Ebola virus as a possible biological weapon during the Cold War. In the 1990s, the Japanese sect AumShinrikyo attempted to acquire and exploit this virus for bioterrorist purposes.The Ebola epidemic in West Africa, which took place between 2013 and 2016, has become a major burden on the world health system. The outbreak has again highlighted the possible role of specialized army components (as well as Haiti earthquake in 2010, disaster recovery after the typhoon in the Philippines in 2013). Ebola affected 28 616 inhabitants of Liberia, Sierra Leone and Guinea; 11 310 died. Other countries - Mali, Nigeria, Senegal, Italy, Spain, the United Kingdom and the US had to deal with at least one case of disease and prevent the spread of the epidemic in their territories.Approximately ten to fifteen thousand cured people continue to face the consequences of the disease. These are, in particular, long-term problems of ophthalmological pain, abdominal pain, digestive tract, insomnia, very severe headaches. A very hot issue today is then recurrent infections in survivors.

Pregnancy related maternal mortality defines the state of maternal health. The increasing incidence of maternal death in the U.S indicates that this complex issue is not unique only to developing countries.  It is obvious that improvements are needed to reinsure appropriate healthcare for all pregnant women.  Without precise methodical data collection and data evaluation advancement of this important determinant of maternal health can’t be achieved.The aim of this paper is to provide contemporary perspective on pregnancy related maternal mortality.  In addition, this paper will discuss common ethnical disparities that underline maternal deaths.  Furthermore, this paper will address the confusing inconsistencies of maternal death terminology and variations in disease classification.  Finally, this paper will propose improvements in defining terminology and data collection that influence the understanding of pregnancy related morbidity.Quick Points - 1. Maternal mortality is a determining characteristic of existing maternal health in a given geographical region. 2. While it is impossible to completely eliminate all maternal deaths, preventable pregnancy complications    resulting in injury or death need to be reduced across the world. 3. Healthcare leaders need to work on identification of maternal mortality trends and development

Kenya is a coastal equatorial state in the eastern part of the African continent with a typically tropical climate. Before visiting of this country (according to the length, character and place of stay), yellow fever, hepatitis A, hepatitis B and typhoid, or rabies, should be inoculated. Another problem is brucellosis or endemic malaria, with a typical occurrence in areas over 2 500 m above sea level, around the capital city of Mombasa and along the coast. Endemic occurrence is also reported for cholera. In standing freshwaters, parasitic infestation with schistosomosis is a threat. Tropical species of invasive mosquitoes are not only vectors for yellow fever, but also dengue and chikungunya could be serious problem.

The Future Forces Forum in Prague occurs biennially and offers a premier venue to exchange best practices, ideas, academic and technical debate with key military decision makers on the future of military medicine. In the over 13 events in modern times, all sectors of military and defense forces have shared experiences, strategies of deterrence, common defense structures and modalities to mitigate human suffering and reduce the morbidity and mortality associated with conflict, war and disaster. Czech Republic Ministry of Defense Brigadier General Bubenik has taken the lead with this event to drive future innovation and all things battlefield medicine, to include chemical, biological, radiological and nuclear threats, with overall emphasis on emerging global health security threats. Under his tutelage, Brig. Gen. Bubenik has ushered in a marque venue for such debate at the Future Forces Forum, Prague 2018 (FFF 2018). The expert event took place from October 17^th to the 19^th, 2018 in Prague. This short conference report should serve as a synopsis of the key takeaways, in addition to highlighting some core conclusions to support all medical operations across NATO and at the civilian-military interface.

Professor Jaroslav Blahoš, MD, DrSc. was born June 30, 1930, and died November 27, 2018. Prof. Blahoš was an exceptional personality in Czech medicine, primarily in endocrinology and osteology. He authored about 380 articles in domestic and international journals as well as 10 monographies. Between 1990 and 2015 he served as Chairman, and later on as Honorary Chairman of the Purkinje Czech Medical Society. Aside from being a highly distinguished physician and scientist, Prof. Blahoš was a leader in organized medicine who helped to reconnect the medical community in the former communist countries with the World Medical Association. In recognition of his achievements the WMA General Assembly elected him President 1999-2000. Prof. Blahoš remained active in global health, last serving on the CIOMS Council for his national J. E. Purkinje Czech Medical Society. Prof. Blahoš will be remembered with gratefulness and respect for his long-term engagement and his friendliness.

Aircrew members of the Czech Air Force are specifically stressed subpopulation of professional soldiers. Besides mental stress, they are exposed to physical stress that requires extraordinary physical fitness. It is most influenced by daily physical activity and nutrition. Dietary intakes of aircrew members that are determined by the legislation of the Ministry of defence cannot adequately reflect energy requirements of duty in all individuals. Thus, the question has arisen whether an actual fitness level of the Czech Air Force aircrew members is sufficient to provide maximal resistance to the negative consequences of an aircraft flying and keep maximal combat readiness. The protective effect of regular and targeted physical activity along with nutritional measures needs to be based on the analysis of dietary intake and energy requirements of the aircrew members when performing duties.

Evidence-Based Toxicology (EBT) was established in 2005 as a tool for toxicological risk assessment and causal link on the basis of the parallel relationship between the toxicological test method evaluation and the Evidence-Based Diagnostic Testing Assessment (EBM). The introduction of evidence-based principles can provide new tools that are necessary to validate toxicological testing methods. EBT should contribute to testing strategies to address toxicology problems in the 21^st century. Practice has shown that the underlying concepts of EBT, such as the use of systematic reviews to capture and consider all available information, improve the results of toxicological assessment conducted by different groups and orga-nizations. New challenges are emerging before toxicology, such as safety assessments of new agrochemicals, pharmaceuticals and nanomaterials, and EBT can provide important results for their application in practice.

Perfluoroisobutene (PFIB) is a colorless toxic gas which can be absorbed into the body by inhalation. The substance irritates the respiratory tract and may be used as a potential chemical warfare agent.  Inhalation exposure may cause severe symptoms of pulmonary edema associated with wheezing, difficulty in breathing and sputum expectoration. A bluish skin color is also observed. Initially, cough and chest pain may occur. However, severe symptoms of pulmonary edema may be delayed for several hours before a rapid deterioration of health occurs. Excessive exposure may cause death.

Background. Extracts from plant and/or animal tissues are frequently used in alternative medicine as drugs or food supplements. Such extracts may contain a complex of pharmacologically or physiologically active factors but frequently there exists no experimental confirmation as to precise mechanisms of action. This work aimed to verify if a long used bovine blood extract Imuregen registered as a food supplement has desirable effect on tumor cells.Methods. Two independent methodological approaches were used. Viability of cell cultures was evaluated using WST-1-based cell cytotoxicity assay. Cell growth was monitored in real time using xCELLigence cell analysis. Normal human adherent lung fibroblasts (NHLF) were used to represent non-tumor lung cells. A human non-small cell lung carcinoma cell line H1299 was used as a model of tumor cells.Results. Our study demonstrated a direct influence on viability of the H1299 tumor cell line (p < 0.005) and a cytostatic/cytotoxic effect of the bovine blood extract after 72h. of cultivation while leavingnon-tumor NHLF cell line unaffected. The extract (0.1 µg/ml and 1 µg/ml, resp.) also significantly affected the viability of irradiated H1299 tumor cell line (p < 0.005, Co, 4Gy) compared to non-tumor irradiated counterparts. In addition to the cytotoxic effect, the extract slightly modified the generation time of the cells and substantial differences between the effects on tumor and non-tumor cell lines were observed.Conclusion. The data presented here might suggest the extract intervenes into the proliferative cell cycle and subsequently influences the generation time of cells. Further analyses should be oriented toward the effects of animal tissue extracts on cellular systems defending against tumors and/or infections and intercellular communications that lead to influencing the fate of individual cell types.

Imuregen is a unique dietary supplement that was developed by leading Czech immunologists, made and distributed from the Czech Republic, and first came out in the 1950s. Imuregen boasts of decades of research and clinical exposure. It was created for the immune system sourced only from all natural ingredients that support cellular immunity and energy, tissue regeneration, wound healing, endocrine gland repair, intestinal integrity, memory enhancement, and has antitumor effects.

Nerve agents (NAs) belong to family of organophosphorus inhibitors (OPIs) of acetylcholinesterase (AChE) enzyme. Although the use of highly toxic OPIs as chemical warfare agents is prohibited, they have been misused several times and thus still represents an emerging threat. For these reasons, the development of novel prophylactic agents and therapeutic intervention against NAs is still up-to-date and of high importance. Prophylactic administration of antidotes not only increases body's resistance to the effects of NAa, e.g. when operating at a contaminated environment after a terrorist attack, but also potentiates the subsequent antidotal therapy after exposure. Currently, pharmacological prophylaxis can be delivered either by protection of AChE against irreversible Inhibition, administration of commonly used antidotes in advance (i.e. oxime reactivators) or by the use of bioscavengers. The aim of the recent review is to highlight the current trends in prophylaxis and outline breakthroughs in prophylaxis based on reversible cholinesterase inhibitors like huperzine A or acridine derivatives.

Exsanguination is one of the leading causes of death in a battlefield. Patients who require cardiopulmonary resuscitation after moribund trauma have an unfavorable prognosis. The determinant of survival in critically injured is a time to surgical intervention. Resuscitative emergency thoracotomy may be the lifesaving treatment in selected patients with trunk trauma and cardiac arrest after hemorrhagic shock.This is a case report of successfully applied resuscitative surgical techniques in severely injured allied soldier with hemorrhagic shock and cardiac arrest after suicide bomber explosion. A prompt diagnosis and a rapid emergency thoracotomy are lifesaving in moribund penetrating or blunt trunk trauma.

Internal medical disciplines (internal medicine and other internal specialties) are among the key clinical branches for the Ministry of Defence and the military medical service. The work provides an overview of the current state of internal medical disciplines within the Ministry of Defence. The main problem is the lack of qualified medical personnel and a complicated system of specialized training due to complexity of these fields. The results section provides options for the further development of internal medical disciplines to secure fulfilment of tasks of military medical service in favour of the Ministry of Defence, in the field of therapeutic-preventive, pedagogical-educational and scientific-research. Internal medicine is a fundamental branch of military health care and the model of a possible development way of one discipline is applicable also to other medical disciplines.

Introduction: Metabolic changes induced by stress reaction are, among other things, characterized by increased turnover of non-esterified fatty acids (NEFA), which results in an increase in their plasma concentration. The aim of the study was to determine how intravenous nutritional support (TPN) will affect the concentration of NEFA in critically ill individuals. Methods: 38 patients in averaged 65 ± 11 years old hospitalized in a medical intensive care unit of university hospital in years 2015-2018 were examined. They were given isocaloric (30 kcal/kg/day) and isonitrogenic (1.8 g/kg/day) TPN in combination with glucose (5.8 g/kg/day; glucose group, G) or in combination with glucose (2.9 g/kg/day) and lipid emulsion (1.2 g/kg/day; lipid group, L). NEFA measurements were performed before starting TPN (day 0) and then at days 1, 3, 6, 9, 14 and 28 using enzymatic and spectrophotometric method. Statistical program Jamovi and the Mann-Whitney U test were used. Results: There was no significant difference in NEFA concentration (mmol/L) at day 0 (G 0.502 ± 0.291, L 0.409 ± 0.126). There was significant decrement (p < 0.001) in day 1 (G 0.220 ± 0.112, L 0.279 ± 0.126). When comparing both groups decrease was more significant in the G, and statistical significance (p < 0.05) was achieved at days 6, 9, 14 and 28. Conclusion: Starting of TPN results in a decrease of NEFA concentration with a greater effect at a higher glucose dose. Glucose administration is able to modify NEFA turnover in critical illness.

Fatigue is common clinical issue, where previous effort, whether physical or mental leads to a reduction in the ability to perform activities. Fatigue severely affects human performance and error rate. Recently, in addition to researching physical fatigue, great emphasis has been placed on research into mental fatigue. The relationship between the two types of fatigue is intensively investigated. Exploration of fatigue and its impact on job performance in high-risk military occupations aims to reduce error rates and eliminate potentially large damage, injuries and loss of life. In this review are described the basic theses of fatigue, physiological mechanisms of fatigue and the methods of fatigue research.

N-Methyl-D-aspartate (NMDA) receptor belongs to the group of glutamate receptors, which are further divided into ionotropic and metabotropic. It affects synaptic plasticity and the development of neuronal synapsis in CNS. Ionotropic NMDA receptors are activated by glutamate, thereby flowing positively charged ions through the membrane along its concentration gradient. However, glutamate overload leads to excitotoxicity, due to high levels of Ca²⁺, which leads to cell death assocciated with neurodegenerative diseases. NMDA antagonists like dizocilpine reduce intracellular concentration of Ca²⁺ by modulating permeability of NMDA receptor channel. Dizocilpine act as a non-competitive NMDA receptor antagonist with anticonvulsant and anesthetic properties. Its therapeutic use in humans is limited due its numerous side effects, but it is experimentally used as an animal model of schizophrenia.

Hemothorax is a frequent clinical situation often associated with chest injury or with iatrogenic lesions. Spontaneous hemothorax is uncommon and among its cause may include coagulation disorders, pleural, pulmonary or vascular pathology. Diagnostics is based on radiography or ultrasound and thoracentesis which may be also therapeutic solution. The majority of hemothoraxes can be managed non-operatively but hemodynamic instability, the volume of evacuated blood and persisting blood loss or persisting hemothorax require surgery. A surgical approach may vary from open thoracotomy to rapidly developing minimally invasive methods - video-assisted thoracoscopic surgery (VATS) and videothoracoscopy (VTS).

The following thesis focuses on the issues regarding catering and food and its impact on health and life satisfaction of coalition soldiers during their deployment on a military operation in the Middle East area. Obviously, food is a part of our lifestyle and it is certainly an area affecting our life satisfaction, all the more affecting the life satisfaction of soldiers specifically in an armed conflict environment where they are exposed to higher stress conditions. Furthermore, life satisfaction is one of the variables influencing the work itself. And work influences our lifestyle and vice versa. It can be also said that life satisfaction influenced by the working environment also affects the health of soldiers. It turns out that work satisfaction has a very strong and lasting relationship with life satisfaction, as work is a central factor for most people, influencing their identity Firstly, it was necessary to find out and describe information from the area of catering of troops in field conditions and fighting food rations which can be provided to deployed soldiers. The authors’ fundamen-tal research question is how the catering and food in the military operational environment affects the life satisfaction and health of deployed soldiers. To obtain the data, a standardized method, Life satisfaction question-naire (authors: J. Fahrenberg, M. Myrtek, J. Schumacher and E. Brähler, 2001), was used. Food and catering play a very high role in our lifestyle, affects our health and furthermore, the quality of life in any situation. In life satisfaction, Danish soldiers have higher values, followed by American soldiers, and British men are the least satisfied during the foreign operation. The reasons for differences and their clarification corespondes with the last published “Happines Index” which is investigated annually by the United Nations agency.

Many unfavourable factors can affect decontamination efficacy when personnel wearing personal protective equipment are decontaminated prior to their final exit from the hot zone. One of the most important factors is the quality of aerosol, which is determined mainly by the size and amount of droplets. Aerosol quality is closely related to the target area coverage efficacy or to deflection of droplets from the direction of flight, so called drift. Studies comparing, e.g., droplet size, velocity, trajectory, spray height, viscosity, surface tension, and wind speed are scarce. The quality of spraying and its application have been intensively studied by agricultural research since the 1950s. Although this research has specific characteristics, it can provide important guidance for the decontamination of high-risk biological pathogens.

The case report presents a case of a very rare anomaly of bile ducts. A 57-year-old patient underwent elective laparoscopic cholecystectomy. The double duct cysticus was the reason of conversion to open surgery. The findings was confirmed due perioperative cholangiography and histological conclusion. This rare abnormality can cause serious surgical accidents. We present our case to point out possible risks of routine laparoscopic cholecystectomy.

Pregnant or postpartum patients with history of substance use disorder who desire to breastfeed present healthcare providers with numerous issues as drug use increases risk for adverse health outcomes for both the mother and her child. Drug use in the U.S. is common. In 2013, an estimated 24.6 million Americans aged 12 or older were current illicit substance users representing 9.4 % of the population. This statistic unfortunately closely corresponds with substance use in pregnant women. Totally 9% of pregnant women used drugs during their first trimester. Substance use during pregnancy and during breastfeeding presents serious problem for the health of our society. When a mother with a history of illegal/illicit drug use or illegal substance abuse desires to breastfeed, her healthcare providers are faced with several ethical dilemmas. The most obvious is whether she should be allowed to breastfeed her child. Does the benefit of breastfeeding outweigh the risk of possible substance transmission to the infant or is formula feeding safer and more appropriate option for the infant? What is the consequence of formula feeding on the fragile relationship between the newborn and the troubled mother? Lastly, the infant’s right to be breastfed needs to be taken into consideration as a part of this complex issue. Healthcare leaders need to be able to understand ethical challenges of this specific population, acknowledge variances between individual substances, and most importantly differentiate between occasional drug use, diagnosable substance use disorder and treated substance use disorder. Healthcare leaders should be able to clearly identify how to best provide the most effective and supportive care. Changes to policies and healthcare practices can advance the overall health of this specific and challenging population as well as can improve the relationship between these patients and their healthcare providers.

The synaptic enzyme acetylcholinesterase (AChE) terminates transmission at cholinergic synapses by rapidly hydrolysing acetylcholine. Examination of the 3D structure of AChE¹ shows that the active site is located at the bottom of a deep and narrow gorge, lined largely by aromatic residues, with its peripheral anionic site located at the top, near the entrance to of the gorge. 3D structures of AChE have been determined for the Torpedo, Electrophorus, mouse, Drosophila and human enzymes. Overall, more than a hundred crystal structures of AChEs, and of covalent conjugates and reversible complexes with various inhibitors and substrate analogues have been determined. Although the 3D structure of the enzyme itself, and of its molecular dimer, are highly conserved, subtle structural differences are seen to occur upon the binding of certain inhibitors. These changes are well correlated with molecular dynamics data, and appear to be of functional significance. Unfortunately, upon heterologous overexpression, many proteins misfold or aggregate, thus resulting in low functional yields. Human AChE is a typical case of a human protein that necessitates mammalian systems to obtain functional expression. Using a novel computational strategy, we designed an AChE variant bearing 51 mutations that improved core packing, surface polarity, and backbone rigidity. This variant expressed at ~2,000-fold higher levels in E. coli compared to wild-type hAChE, and exhibited 20°C higher thermostability with no change in enzymatic properties or in the active-site configuration as determined by crystallography^2,3.

The state of the lipid interface is known to influence activity of membrane-bound enzymes. Indeed, many enzymes exhibit changes in activity at phase transitions in the membrane to which they are attached. We utilized a Langmuir trough in which detergent-soluble Torpedo californica acetylcholinesterase (DS-TcAChE)¹ was anchored to the solvent face of a phospholipid monolayer in order to study this phenomenon. A peak in activity was observed at the compressibility maximum accompanying the transition between the ordered and fluid phases. Neither molecular nor physical alterations affected this correlation qualitatively, as shown by varying lipid type, pH over 2 units, temperature over 20°C, and lateral pressure over 10 mN/m. Thus the only consistent correlation is between the thermodynamic state of the interface and the measured activity. Our data are consistent with a theory in which the interface state and its corresponding fluctuations control catalytic activity². It was earlier demonstrated that pH-pulses initiated by local acidification of the monolayer propagate, in analogy to sound, at velocities up to 1.4 m/s³. We have now shown that such a pulse, by transiently modifying compressibility, can concomitantly and reversibly enhance the activity of DS-TcAChE attached to the monolayer. Our data demonstrate a feasible mechanism for signaling between widely separated biological entities that differs fundamentally from the molecular mechanisms currently accepted, and is also very much faster.

The best-known function of acetylcholinesterase (AChE) is the hydrolysis of the neurotransmitter acetylcholine, however we are increasingly aware of the multifunctionality of this enzyme [1]. The non-hydrolytic functions of AChE are driven by allosteric sites as the peripheral allosteric site (PAS) responsible for amyloidosis in Alzheimer’s disease through interaction with β-amyloid peptide. We would like to show our work about the identification and characterization of new allosteric sites in AChE, using computational tools. This study has allowed us to identify allosteric inhibitors by virtual screening using our in-house MBC chemical library [2] guided by structure-based and fragment hotspot strategies. The identified compounds were also screened for in vitro inhibition of AChE and three of them were observed to be active. Further experimental (kinetic) and computational (molecular dynamics) studies have been performed to verify the allosteric activity. Thus, new compounds have been developed as allosteric modulators that may be valuable pharmacological tools in the study of non-cholinergic functions of AChE.

Phosphotriesterase (PTE), an enzyme originally isolated from Pseudomonas diminuta, is capable of catalyzing the hydrolysis of many organophosphorus nerve agents.  The turnover number for the enzymatic hydrolysis of paraoxon (diethyl p-nitrophenyl phosphate) by PTE is ~500,000 min^-1.  The protein adopts a distorted (β/α)₈-barrel structural fold and the active site is perched at the C-terminal end of the β-barrel.  The water used for nucleophilic attack of the substrate bridges two divalent metal ions in the active site and is further activated by the side chain carboxylate from an aspartate residue that resides at the end of β-strand 8.  Upon binding to the active site, substrates are further activated for hydrolysis by a direct interaction of the phosphoryl oxygen with the β-metal ion.  The chemical reaction is initiated via the direct attack of the bridging water/hydroxide at the phosphorus center of the substrate and proceeds with an inversion of stereochemistry.  Wild-type PTE is stereoselective for the hydrolysis of chiral substrates.  However, the catalytic preferences for the hydrolysis of chiral substrates can be enhanced, relaxed, or inverted by selective mutation of key residues in the active site that dictate the size and shape of the substrate-binding cavity.  The extreme toxicity and persistence of the G-type (sarin and soman) and V-type (VX and VR) organophosphorus nerve agents makes the detoxification of these compounds of significant interest.  A rational and random mutagenesis strategy has been developed and implemented for the evolution of mutant forms of PTE that are more fully optimized for the catalytic destruction and detoxification of the most toxic organophosphorus nerve agents.

The mechanism of toxicity from acute exposure to organophosphorus toxicants (OP) is understood.  Thousands of publications have confirmed that AChE inhibition results in muscle weakness and respiratory failure.  AChE activity returns to normal levels within one month, but symptoms can persist for a lifetime.  For example, people exposed to sarin in the 1995 Tokyo subway attack still have adverse symptoms 23 years later.  Farmers and sheep dippers exposed to OP pesticides have an elevated risk of psychiatric disorders and suicidal behavior.  Epidemiology studies show an association between OP exposure and Alzheimer’s disease and Parkinson’s disease.  We propose a mechanism to rationalize these observations independent of cholinesterase inhibition.  Mass spectrometry analysis of OP-treated proteins shows that OP make stable adducts on tyrosine and lysine.  Furthermore, we have mass spectrometry evidence that OP-lysines promote crosslinks between proteins.  The crosslinked proteins are visualized as protein aggregates on SDS gels and Western blots.  Mass spectrometry has identified γ-glutamyl-ε-lysine and aspartyl-ε-lysine isopeptide bonds between crosslinked peptides.  We propose, but have not yet proven, that isopeptide crosslinked proteins form stable, insoluble aggregates in the brain, similar to the protein aggregates found in Alzheimer’s, Parkinson’s, and prion diseases.  In summary, we propose that chronic neurotoxicity from OP exposure is initiated by OP-lysine formation followed by protein aggregation.  Our proposed mechanism could apply to a variety of compounds and lead to an understanding of neurotoxicity induced by many chemicals.