Timmons PR

References (5)

Title : Brain acetylcholinesterase, acid phosphatase, and 2',3'-cyclic nucleotide-3'-phosphohydrolase and plasma butyrylcholinesterase activities in hens treated with a single dermal neurotoxic dose of S,S,S-tri-n-butyl phosphorotrithioate - Abou-Donia_1986_Toxicol.Appl.Pharmacol_82_461
Author(s) : Abou-Donia MB , Abdo KM , Timmons PR , Proctor JE
Ref : Toxicol Appl Pharmacol , 82 :461 , 1986
Abstract : The changes in brain acetylcholinesterase (AChE), acid phosphatase (APase), and 2',3'-cyclic nucleotide-3'-phosphohydrolase (CNP), and plasma butyrylcholinesterase (BuChE) activities were investigated in hens treated with a single, dermal dose (100-1000 mg/kg) of S,S,S-tri-n-butyl phosphorotrithioate (DEF). Three control groups consisted of hens left untreated, given a single, dermal dose of 500 mg/kg tri-o-cresyl phosphate (TOCP, positive control for organophophorous compound-induced delayed neurotoxicity), or 10 mg/kg O,O-diethyl O-4-nitrophenyl phosphorothioate (parathion, negative control). Brain AChE activity, determined 28 days after application, was significantly inhibited in hens given 500-1,000 mg/kg DEF and in TOCP- and parathion-treated hens. In contrast, brain APase and CNP activities were significantly higher in all treatments as compared with those of the untreated hens. Parathion, however, caused the least increase in these enzymatic activities as compared to DEF or TOCP. A single, dermal dose of DEF or TOCP also caused an initial decrease in plasma BuChE activity with maximum depression of enzymatic activity observed 1 to 7 days after administration. This decrease was dose dependent and the enzymatic activity showed partial recovery with time. Hens treated with single, dermal doses of DEF, ranging from 250 to 1000 mg/kg, developed ataxia which progressed to paralysis in some hens. Histopathologic examination revealed axon and myelin degeneration of the spinal cord and peripheral nerves of some hens. The severity and frequency of the neuropathologic lesions were dose dependent. Neurologic dysfunctions and neuropathologic lesions seen in DEF-treated hens were similar to those exhibited in TOCP-treated hens. While parathion produced acute cholinergic effects, it did not cause delayed neurotoxicity. The changes in brain and plasma enzymes are discussed in relation to their role in the pathogenesis of DEF-induced delayed neurotoxicity.
ESTHER : Abou-Donia_1986_Toxicol.Appl.Pharmacol_82_461
PubMedSearch : Abou-Donia_1986_Toxicol.Appl.Pharmacol_82_461
PubMedID: 3952729

Title : Heinz body production and hematological changes in the hen after administration of a single oral dose of n-butyl mercaptan and n-butyl disulfide - Abdo_1983_Fundam.Appl.Toxicol_3_69
Author(s) : Abdo KM , Timmons PR , Graham DG , Abou-Donia MB
Ref : Fundamental & Applied Toxicology , 3 :69 , 1983
Abstract : n-Butyl mercaptan (nBM) is a breakdown product of S,S,S,-tri-n-butyl phosphorotrithioate (DEF) and S,S,S-tri-n-butyl phosphorotrithioite (merphos) in hens and in the environment. n-Butyl disulfide (nBD) is an oxidation product of nBM. A single 500 mg/kg dose of nBM and nBD was administered in gelatin capsules to groups of five 12-month old laying hens. A third group (five hens) was given gelatin capsules. One day after administration, the hens exhibited weakness which progressed to unsteadiness and inability to stand by the third day. These signs were accompanied by a pale comb 18--24 hr after dosing, which changed to dark color at 48 hr. Treated hens improved with time. Heinz bodies and extensive erythrocyte deformation and lysis were observed in blood smears taken from hens 24 and 48 hr after treatment. Hemoglobin concentration, packed cell volume, erythrocytes, and glucose-6-phosphate dehydrogenase activity were significantly lower than controls, while methemoglobin was significantly higher. As the clinical condition of these hens improved, these hematologic changes disappeared. nBM caused an initial increase in plasma butyrylcholinesterase activity which was dose-dependent and returned to normal by the end of the 28-day experiment. Also, brain acetylcholinesterase activity was not different from that of the control at termination.
ESTHER : Abdo_1983_Fundam.Appl.Toxicol_3_69
PubMedSearch : Abdo_1983_Fundam.Appl.Toxicol_3_69
PubMedID: 6873530

Title : Effects of a dermal dose of S,S,S,-tri-n-butyl phosphorotrithioate on brain acetylcholinesterase, acid phosphatase, and 2',3'-cyclic nucleotide-3' phosphohydrolase and plasma butyrylcholinesterase in hens -
Author(s) : Abdo KM , Timmons PR , Abou-Donia MB
Ref : Developments in Toxicology & Environmental Sciences , 11 :499 , 1983
PubMedID: 6329633

Title : Late acute, delayed neurotoxic and cholinergic effects of S,S,S- tributyl phosphorotrithioite (Merphos) in hens -
Author(s) : Abou-Donia MB , Graham DG , Timmons PR , Reichert BL
Ref : Toxicol Appl Pharmacol , 53 :439 , 1980
PubMedID: 7385244

Title : Delayed neurotoxicity of leptophos and related compounds: differential effects of subchronic oral administration of pure, technical grade and degradation products on the hen -
Author(s) : Abou-Donia MB , Graham DG , Ashry MA , Timmons PR
Ref : Toxicol Appl Pharmacol , 53 :150 , 1980
PubMedID: 6155716