Delayed neurotoxicity of leptophos: Toxic effects on the nervous system of hens

Delayed Neurotoxicity of Phenylphosphonothioate Esters

“…Degeneration of the anterior columns of thoracic and lumbar spinal cord was the most consistent histological correlate of delayed neurotoxicity. This study confirms earlier results (6)(7)(8)(9)17) showing that the lesions in the peripheral nerve occur earlier than those in the spinal cord as seen by the light microscope. This might be attributed in part to the fact that the peripheral axons can regenerate, whereas those in the central nervous system cannot.…”

“…Recently, the phenylphosphonothioate insecticide leptophos has been implicated in the poisoning and paralysis of some workers in Texas (4). Leptophos produces delayed neurotoxicity in farm animals and chickens (5)(6)(7)(8)(9). A photodegradation product of this compound, desbromoleptophos (DBL), was reported to cause delayed neurotoxicity in chickens (10).…”

“…Body weights were monitored and hens were examined periodically for neurological signs of delayed neurotoxicity. Nerve tissues were 0036-8075/79/0817-0713$00.50/0 Copyright © 1979 AAAS excised and prepared for histological examination in birds that died during the experiment and in birds killed by heart puncture at the end of the 60-day test period (6). Sections from brain, spinal cord, and sciatic nerve (8 ,m) were stained with hematoxylin and eosin combined with luxol fast blue.…”

“…Several substances isolated from the CNS compete with tritiated benzodiazepines for CNS receptor sites (5). These endogenous substances have been identified as the purine hypoxanthine and its nucleoside inosine (6), both of which are synthesized de novo in neuronal tissue (7). In addition to their function in nucleic acid synthesis, purines can be released from nerve tissue (8,9) and alter the excitability of central (10) and peripheral neurons and smooth muscle (11), results suggesting that these compounds may mediate intercellular communication in the nervous system (9)(10)(11).…”

Delayed neurotoxicity of cyanofenphos in chickens

“…Human exposure to some of these chemicals could lead to injury of the nervous system involving axonal and/or myelin disruption. The clinical symptoms termed "delayed neurotoxicity" are usually not seen until [8][9][10][11][12][13][14] days after exposure 1 . Newly discovered compounds are subjected to condensed studies in an attempt to detect those with maximum effect to insects and other pests without any side effect to humans.…”