Medical Aspects of Chemical Warfare (2008) - The Black Vault

Medical Aspects of Chemical WarfareTABLE 5-1RELATION OF EFFECTS OF NERVE AGENT EX-POSURE TO ERYTHROCYTE CHOLINESTERASE ACTIVITYEffectPatientsAffected(N=62)Range of RBC-ChE Activity(% of Baseline*)Miosis alone (bilateral) 22 0–100Miosis alone (unilateral) 7 3–100Miosis and tight chest 12 28–100Miosis and rhinorrhea 9 5–90Miosis, rhinorrhea, and 9 20–92tight chestRhinorrhea and tight chest 3 89–90the authors observed that patients had an RBC-ChEactivity of 0% without the expected symptoms; thisinhibition was acutely induced.Data from 283 individuals who received VX byvarious routes are categorized below (Table 5-2). Thedegree of inhibition needed to cause vomiting in these283 people corresponds to that found in experimentaldata from other sources, which indicate that “to exertsignificant actions in vivo, an anti-ChE must inhibitfrom 50% to 90% of the enzyme present.” 14(p446)Nerve AgentsMolecular models of the nerve agents tabun, sarin,soman, and VX are shown in Figure 5-3. The chemical,physical, and environmental properties of thesecompounds are summarized in Table 5-3. Nerveagents differ from commonly used ChE inhibitors*Cholinesterase activity before nerve agent exposure.RBC-CHE: red blood cell cholinesterase.Data source: Sidell RF. Clinical considerations in nerve agent intoxication.In: Somani SM, ed. Chemical Warfare Agents. San Diego, Calif:Academic Press; 1992: 163.abminimal enzyme activities were 20% to 29% of control,and in 3 (60%) of 5 subjects whose minimal RBC-ChEactivities were 0% to 19% of control. In other instances,TABLE 5-2RELATION OF CHOLINESTERASE ACTIVITYTO VOMITING AFTER EXPOSURE TO VXcMinimumRBC-ChE(% of Baseline*)Patients(N=283)PatientsVomitingPercentageVomiting> 50 166 1 0.640–49 24 2 8.330–39 27 9 33.320–29 42 19 45.2< 20 24 16 66.7d*Cholinesterase activity before nerve agent exposureRBC-ChE: red blood cell cholinesterase.Data sources: (1) Sidell FR, Groff WA. The reactivatibility of cholinesteraseinhibited by VX and sarin in man. Toxicol Appl Pharmacol.1974;27:241–252. (2) Sim VM. Variability of Different Intact HumanSkin Sites to the Penetration of VX. Edgewood Arsenal, Md: MedicalResearch Laboratory; 1962. Chemical Research and DevelopmentLaboratory Report 3122.Fig. 5-3. Molecular models of (a) Tabun (GA), (b) Sarin (GB),(c) Soman (GD), (d) VX.Molecular models: Courtesy of Office E Clark, Researcher,US Army Medical Research Institute of Chemical Defense,Aberdeen Proving Ground, Md.166