Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.1.5 (neuropathy target esterase)
 1,070 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An avian reaggregate culture system was characterized biochemically and morphologically for use in acute and chronic organophosphorus compound (OP) toxicity studies. Ten-day-old chick embryo brains were dissociated, reaggregated, and maintained in a chemically defined, serum- and antibiotic-free media. Acetylcholinesterase (ACHE), neuropathy target esterase (NTE), and 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) were examined due to inhibition of these enzymes as a result of acute OP toxicity (ACHE) or delayed toxicity (NTE, CNP). The selected enzymes also indicate reaggregate neuronal (ACHE, possibly NTE), oligodendroglial (CNP), and astrocytic (glutamine synthetase (GS)) activities. Enzyme activities were compared to those in age-matched chick embryo and hatched chick brains. Reaggregate ACHE specific activity was similar to or higher than that of chick embryo or hatched chick. Reaggregate NTE specific activity was initially similar to that of 10-day-old chick embryo, and then increased but subsequently averaged 7.8 nmol/min/mg protein. In chick brain, NTE peaked at hatching and averaged 28 nmol/min/mg protein thereafter. Reaggregate CNP specific activity ranged from 103 to 426 nmol/min/mg protein, whereas activity gradually increased in chick embryo brain to an average of 140 nmol/min/mg protein posthatching. The mean GS activity ranged from 0.15 (Culture Day 4) to 1.09 nmol/min/mg protein (Culture Day 62). Mean protein values per flask ranged from 2.47 to 7.58 mg. Ultrastructurally, myelination was detected at Culture Day 7 and synapses at Day 6. The biochemical and ultrastructural features demonstrate that this reaggregate culture is a practical and sensitive in vitro system for studying both the acute and the long-term neurotoxicological effects of organophosphorus compounds.
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PMID:Avian embryonic brain reaggregate culture system. I. Characterization for organophosphorus compound toxicity studies. 790 78

Biochemical responses after a single exposure to either a neuropathic or a nonneuropathic organophosphorus compound (OP) were compared using chick embryonic brain cell reaggregates. Ten-day-old chick embryo brains were dissociated and then reaggregated and maintained in a chemically defined, serum-free medium without antibiotics. Seven days later, these cultures were treated for 20 min with either neuropathic diisopropyl phosphorofluoridate (DFP, 10(-4) M) or nonneuropathic paraoxon (10(-6) M). Reaggregates were assayed for acetylcholinesterase (ACHE), neuropathy target esterase (NTE), and 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) activities for up to 32 days after exposure. These enzymes were examined due to inhibition of activity as a result of acute OP toxicity (ACHE) or delayed toxicity (NTE, CNP). DFP inhibited > 95% of NTE activity immediately after exposure. By Postexposure Day 2, NTE specific activity was 22% of untreated activity but was similar to the untreated group levels by Postexposure Day 7. Paraoxon exposure did not affect NTE activity. Both paraoxon and DFP inhibited > 99% of ACHE activity immediately after exposure. By Postexposure Day 2, ACHE specific activity in paraoxon-exposed cultures had recovered while ACHE remained 56% inhibited in DFP-exposed cultures. Both paraoxon- and DFP-exposed cultures recovered ACHE activity immediately following OP exposure if treated postexposure with an oxime reactivator, 2-pralidoxime. CNP specific activity was not affected by either paraoxon or DFP. These results demonstrated distinct differences in reaggregate NTE and ACHE activities after single exposure to neuropathic DFP and nonneuropathic paraoxon similar to those in avian in vivo assays.
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PMID:Avian embryonic brain reaggregate culture system. II. NTE activity discriminates between effects of a single neuropathic or nonneuropathic organophosphorus compound exposure. 829 Oct 56