On the battlefields of Syria, many innocent civilians have been killed or injured by sarin poisoning. In Malaysia in February 2017, a North Korean man was assassinated with VX at Kuala Lumpur International Airport. In the face of such threats, a more effective antidote against organophosphonate acetylcholinesterase (AChE) inhibitors is needed, one that can freely penetrate into the central nervous system (CNS) through the blood-brain barrier (BBB). In the 1995 Tokyo subway sarin attack, which produced more than 6,000 victims, 2-pyridinealdoxime methiodide was the most commonly used antidote in hospitals, but it was unable to prevent CNS damage and no other oximes have been approved for use in Japan. Ultimately, 12 people died, and many victims had severe neurological injuries or sequelae. Although more than 25 years have passed since the incident, progress has been slow in the development of a new antidote that can penetrate the BBB, restore AChE activity in the CNS, and definitely prevent brain injury. From the perspectives of countering terrorism and protecting innocent people from nerve agent attacks, the search for nerve agent antidotes should be accelerated with the goals of improving both survival and quality of life. This review gives an overview of a series of our studies on the development of a new antidote since the Tokyo subway sarin attack and emphasizes that there is unfortunately still no promising antidote for saving the CNS in Japan.
Attention has been paid to neurobehavioral effects of occupational and environmental exposures to chemicals such as pesticides, heavy metals and organic solvents. The area of research that includes neurobehavioral methods and effects in occupational and environmental health has been called "Occupational and Environmental Neurology and Behavioral Medicine." The methods, by which early changes in neurological, cognitive and behavioral function can be assessed, include neurobehavioral test battery, neurophysiological methods, questionnaires and structured interview, biochemical markers and imaging techniques. The author presents his observations of neurobehavioral and neurophysiological effects in Tokyo subway sarin poisoning cases as well as in pesticide users (tobacco farmers) in Malaysia in relation to Green Tobacco Sickness (GTS). In sarin cases, a variety effects were observed 6-8 months after exposure, suggesting delayed neurological effects. Studies on pesticide users revealed that organophosphorus and dithiocarbamate affected peripheral nerve conduction and postural balance; subjective symptoms related to GTS were also observed, indicating the effects of nicotine absorbed from wet tobacco leaves. In addition, non-neurological effects of pesticides and other chemicals are presented, in relation to genetic polymorphism and oxidative stress.