Intoxication, organophosphorus compounds

For example, no difference in the toxicity of organophosphorus compounds to larvae of the midge Chrironomus riparius was observed between pulsed and continuous exposures (Kallander et al. 1997). In the same study, however, two 1-hour pulses caused significantly fewer symptoms of intoxication than 2 hours of continuous exposure to carbamate compounds, when animals were placed in clean water for at least 2 to 6 hours between treatments (Kallander et al. 1997), suggesting that detoxification or elimination of the toxicant during the toxicant-free period can reduce the toxic effects of the earlier exposures. 

Maksimovic, M., Boskovic, B., Radovic, L., Vadic, V., Deljac, V., and Binenfeld, Z., Antidotal effects of bis-pyridinium-2-monoxime carbonyl derivatives in intoxications with highly toxic organophosphorus compounds, ActaPharm. Jugosl., 30,151-160,1980. 

It Is well known that phosphorothlonate insecticides such as parathlon (, 0-diethyl p-nitrophenyl phosphorothloate) and malathion [0, -dimethyl -(l,2 -dlcarbethoxy)ethyl phosphoro-dithioate] are Intrinsically poor inhibitors of acetylcholinesterase and in vivo activation to the respective anticholinesterases paraoxon and malaoxon is required before animals exposed to the phosphorothionates are intoxicated. Since metabolic activation is essential to the biological activity of these thiono sulfur-containing organophosphorus insecticides, compounds of this type may be considered as propesticides or, more specifically, prolnsectlcldes. 

The organophosphorus (OP) and carbamate insecticides are used to control a wide variety of insect pests. The acute toxicity of the OPs and carbamates varies, and many of them have high mammalian toxicity. These compounds react chemically with the active site of acetylcholinesterase, producing a blocked enzyme that cannot degrade acetylcholine. The concentration of acetylcholine then builds up and hyperexcitation occurs. The signs of intoxication include resdessness, tremors, convulsions, and paralysis. Blockage of acetylcholinesterase by OPs is persistent, and recovery of the enzyme takes many hours or even days. The mode of action of the carba-... 

Elhn, R.I. 1981. Anomalies in Theories and Therapy of Intoxication by Potent Organophosphorus Anticholinesterase Compounds. Special Publication USA-BML-SP-81-003. DTIC AD-A101364. U.S. Army Medical Research and Development Command, Biomedical Laboratory, Aberdeen Proving Ground, Edgewood, Md. 

Ellin, R.I. (1982). Anomalies in theories and therapy of intoxication by potent organophosphorus anticholinesterase compounds. Gen. Pharm. 13 457-66. 

Organophosphorus and carbamate compounds have come into widespread use in agriculture, since they show low environmental persistence nevertheless, they exert a high acute toxicity. The principal effect of these compounds is the inhibition of the enzyme acetylcholinesterase (AChE), which is essential for terminating the action of the neurotransmitter acetylcholine (ACh). Actually, the intoxication by these compounds results in... 

The pharmacology of the organophosphorus cholinesterase inhibitors has many facets. Much has been discovered concerning their mode of action and the therapeutic measures to be adopted in the event of intoxication by these compounds. Accepting the specificity of the antidotes used in these therapies, laboratory studies with them may indicate the principal locus of the toxic effects of the organophosphates. Because of the multiplicity of the biological effects of the organophosphorus pesticides, whether these effects... 

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