Abstract  RDX is an explosive compound widely used by the military and is the main component of the plastic explosive composition C-4. RDX has been detected as a soil and groundwater contaminant at some Army training facilities. In humans, toxic ingestion or exposure to RDX has caused headache, dizziness, vomiting, confusion, and seizures. However, the mechanism(s) of RDX-induced seizures are not understood. Early behavioral studies speculated that RDX seizures originated in the limbic system, possibly in the amygdala. Thus, our studies began by investigating the electrophysiological effects of RDX on the basolateral nucleus of the amygdala (BLA), the nucleus that is most susceptible to seizurogenic insults. First, we confirmed that RDX administration (75 mg/kg, orally) in male Sprague Dawley rats (275-325g) rapidly caused generalized seizures in vivo, by recording cortical electrographic activity using screw electrodes bilaterally over the frontal and parietal cortices. Next, using whole-cell recordings in the voltage-clamp mode, in in vitro brain slices from 14-21 day-old, male Sprague Dawley rats, GABAA receptor-mediated spontaneous inhibitory post-synaptic currents (sIPSCs) were recorded from pyramidal-shaped neurons in the BLA, in the presence of 50 μM D-APV, 50 μM GYKI 53655, and 10 μM SCH50911 to block NMDA, AMPA, and GABAB currents, respectively. Upon application of 30μM RDX, the amplitude, but not frequency, of sIPSCs was markedly reduced. Subsequent application of 10 μM bicuculline completely blocked the sIPSCs, confirming that the currents which were reduced by RDX were mediated by GABAA receptors. We are now constructing a dose-response curve for the effect of RDX on the sIPSCs, as well as for the effect of RDX on IPSCs evoked by local pressure application of variable concentrations of GABA. The reduction of GABAA receptor-mediated currents by RDX in the BLA may be an important mechanism in the generation of seizure activity upon RDX ingestion or exposure.

Abstract  Surrounding vegetation is exposed to a variety of potentially toxic compound S due to unexploded ordnances leaching explosive compounds into the soil. These compounds are absorbed by roots, transported through the vascular system, and distributed throughout plant tissues. Research Demolition Explosive (RDX) (hexahydro-1,3,5-trinitro-1,3,5-triazine) and trinitrotoluene (TNT) (2-methyl-1,3,5-trinitrobenzene) are the most studied; however, mixtures of explosives are widespread in conventional munitions. Composition B (Comp B), a mixture of RDX and TNT, is the most common mixture. Our study objective was to quantify the comparative effects of RDX, TNT and Comp B on the physiology of an evergreen shrub, Morella cerifera. Adult M. cerifera plants were exposed for 7 weeks to soil amended with RDX up to 1500 mg kg(-1) dry soil, TNT up to 500 mg kg(-1) dry soil, and Comp B up to 750 mg kg(-1) dry soil. Stomatal conductance, photosynthesis, leaf water potential, leaf fluorescence, and contaminant uptake values were measured at the end of the experiment. As contaminant concentration increased, significant declines in photosynthesis and leaf fluorescence occurred for all compounds. Overall responses varied between contaminants and impacts of Comp B were largely reduced compared to either RDX or TNT. Of all physiological parameters, photosynthesis was most impacted, making it a sensitive indicator for the detection of explosives. Yet, the intricate relationships within normal physiological processes appear to be severed in the presence of explosives. These disparate responses in plant physiology may serve as a method for explosive contamination stress detection. Our results highlight the importance of studying real world munition mixtures. (C) 2013 Elsevier B.V. All rights reserved.

Abstract  C-4 (cyclonite) explosive ingestions are rarely reported in the literature. We report the case of a canine ingestion of cyclonite that resulted in seizures unresponsive to conventional treatment. Case Report: A 3-year-old, otherwise healthy, male Rottweiler ingested approximately 1 cubic cm of C-4 explosive during an exhibition exercise. The owner reported vomiting after 30 minutes and generalized seizure-like activity 4 hours after ingestion. The dog was brought to a health care center where 8 further generalized seizures occurred over 10 hours. Treatment consisted of several doses of benzodiazepines and barbiturates in addition to supportive care. After the eighth seizure, the dog was placed on a continuous intravenous infusion of propofol, which was continued until 60 hours after ingestion. A granular odorous material was retrieved rectally after several high warm saline enemas. The dog made a complete recovery and was released after 72 hours. Conclusion: C-4 (cyclonite) ingestion is rarely reported in the literature. Seizures that occur after exposure may be prolonged and recalcitrant to conventional therapy warranting aggressive treatment.