Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004134 (ataxia)
 15,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tri-o-cresyl phosphate (TOCP), which produces a delayed neurotoxic syndrome in humans and some animal species, was given to Fischer 344 (F344) male (18 week old) rats to determine if it causes biochemical, sensorimotor, and neuropathological effects. Animals were given TOCP by gavage in doses ranging from 10 to 100 mg of TOCP/kg daily for a period of 63 days. The rats were subjected to a series of neurobehavioral tests including fore- and hindlimb grip strength, motor activity, tremor, and latency to respond to a thermal stimulus. Central and peripheral nervous tissues were examined for damage characteristic of organophosphorous compound-induced delayed neurotoxicity (OPIDN). Brain neurotoxic esterase and acetylcholinesterase activities were inhibited in a dose-dependent fashion. A group of three chickens treated with 100 mg of TOCP/kg/day for 18 days was included as the positive control for enzymatic and histopathological alterations associated with OPIDN. Rats showed no consistent neurobehavioral changes or evidence of neuropathological damage in nervous tissues associated with treatment. In contrast, chickens treated with TOCP developed delayed neurotoxicity characterized by ataxia, which progressed to paralysis. These neurological changes included swelling, fragmentation, and degeneration of the axon and myelin in both central and peripheral nervous tissues. This study concludes that the F344 rat is not sensitive to the delayed neurotoxic effects of TOCP. When studying OPIDN in rats, care must be exercised in choosing the experimental animal since some strains, e.g., F344, are not sensitive.
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PMID:Lack of delayed neurotoxic effect after tri-o-cresyl phosphate treatment in male Fischer 344 rats: biochemical, neurobehavioral, and neuropathological studies. 335 6

Organophosphorus compounds which, after acute administration, inhibit neurotoxic esterase (NTE) by greater than or equal to 65% and undergo a subsequent "aging" reaction, produce a delayed neuropathy characterized by degeneration of large and long nerve fibers (OPIDN). The present studies examine in detail the NTE-inhibiting properties of triphenyl phosphite (TPP), a plasticizer which produces ataxia and degeneration of the spinal cord in animals. A neurotoxic dosing regimen (1184 mg/kg/week, sc, for 2 weeks) inhibited both brain and spinal cord NTE (less than or equal to 40%) only marginally 4 and 48 hr postdosing. By contrast, TPP was shown in vitro to be a potent (150 = 0.98 microM) inhibitor of rat brain NTE relative to Mipafox or diisopropyl phosphorofluoridate. Compounds structurally related to TPP (i.e., triphenyl phosphate, triphenyl phosphine, trimethyl phosphite, and phenol) failed to inhibit NTE in vitro at less than 10 microM concentrations. Close examination of the TPP inhibition of NTE showed a nonlinear relationship between the duration of incubation time and loss of log(NTE activity). Preincubation of 10 microM TPP in buffer (37 degrees C) resulted in a time-dependent loss of TPP's ability to inhibit NTE. In summary, TPP is a powerful NTE inhibitor in vitro, but only a marginal NTE inhibitor after in vivo administration. These results raise questions as to the causal events mediating TPP-induced neuropathy in the rat.
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PMID:Triphenyl phosphite: in vivo and in vitro inhibition of rat neurotoxic esterase. 382 83

The sensitivity of the mouse to organophosphorus-induced delayed neurotoxicity (OPIDN) has been investigated. One group of five mice received two single 1000-mg/kg po doses of tri-o-cresyl phosphate (TOCP) at a 21-day interval (on Days 1 and 21 of the study); a second group of five mice was given 225 mg/kg of TOCP daily for 270 days. A third group of five animals served as an untreated control. All animals were killed 270 days after the start of the experiment. Daily po dosing of 225 mg/kg TOCP caused a decrease in body weight gain, muscle wasting, weakness, and ataxia which progressed to severe hindlimb paralysis at termination. On the other hand, po administration of two single 1000-mg/kg doses of TOCP at a 21-day interval produced no observable adverse effects. Brain acetylcholinesterase (AChE) and neurotoxic esterase (NTE) activity were 35 and 10% of the control, respectively, in daily dosed animals while AChE and NTE in mice receiving two single 1000-mg/kg doses of TOCP were not significantly altered from the control group. Plasma butyrylcholinesterase activity was 12% of the control group in daily dosed animals. Hepatic microsomal enzyme activities of aniline hydroxylase and p-chloro-N-methylaniline demethylase and NADPH-cytochrome P-450 content in daily dosed animals were increased (141 to 161% of the control group) when compared to controls and mice receiving two single 1000-mg/kg doses of TOCP; the latter being not significantly different from each other. Degeneration of the axon and myelin of the spinal cord and sciatic fascicle were observed and were consistent with OPIDN. This study demonstrates that chronic dosing of TOCP produces OPIDN and induces hepatic microsomal enzyme activity in mice. It is concluded that while the mouse is susceptible to OPIDN, it is a less sensitive and a less appropriate test animal for studying this effect when compared to the adult hen.
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PMID:Characterization of delayed neurotoxicity in the mouse following chronic oral administration of tri-o-cresyl phosphate. 404 9

Trio-o-cresyl phosphate (TOCP), leptophos [O-methyl O-(4-bromo-2,5,-dichlorophenyl) phenylphosphonothioate] and cyanofenphos [O-ethyl O-(4-cyanophenyl) phenyl-phosphonothioate] were used to determine whether adult peking ducks would exhibit neurotoxicity after exposure to such chemicals. Clinical, histopathological, and specific biochemical tests were used to detect the neurologic dysfunctions that were induced by these neurotoxic agents. Ducks were orally treated with TOCP or leptophos at 100 or 10 mg/kg X d for 30 d, respectively. Another group of ducks received cyanofenphos at 4 mg/kg X d for 10 d. All the TOCP- and leptophos-treated ducks developed clinical signs of delayed neuropathy, as manifested by ataxia and paralysis. Two of the cyanofenphos-treated ducks died from cholinergic effect during the course of dosing. Surviving ducks of this group completely recovered from the cholinergic effect 2 or 3 d after finishing the dosing regimen. However, they developed signs of delayed neurotoxicity 10-17 d later. Surviving ducks of all groups were sacrificed for biochemical and/or histopathologic tests 1 d after the last treatment or when they became paralyzed. Histopathologic examinations indicated that degenerative lesions of axons consistent with the type occurring in delayed neurotoxicity were seen in all TOCP-, leptophos-, or cyanofenphos-treated ducks and were specially evident in sections of spinal cord. Biochemically, it was found that duck brain neurotoxic esterase (NTE) activity was inhibited in vivo to less than 15% of control levels as measured 24 h after the last treatment with TOCP, leptophos, or cyanofenphos. These results indicate that adult peking ducks could be used to screen organophosphorus compounds for delayed toxic neuropathy.
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PMID:Delayed neuropathy in adult Peking ducks induced by some organophosphorus esters. 608 66

Five organophosphorous insecticides: Leptophos, EPN, Cyanofenphos, trichloronate and salithion proved to cause irreversible ataxia not only to chicken but also to mice and sheep. TOCP was included as a reference. Cyanofenphos blocked the catecholamine B-receptor binding activity with 3H-norepinephrine at a level similar to that of the specific inhibitor propranolol in the mouse heart preparation. In the lamb heart preparation, the B-receptor was more sensitive to Leptophos, salithion and TOCP than to propranolol. The six compounds and their oxons were screened for their in-vitro inhibition to monamine oxidase (MAO), acetyl cholinesterase (AChE) and neurotoxic esterase (NTE) in the brain of either mouse, lamb or chicken. It is believed that their AChE inhibition stands for their acute toxicity, while NTE inhibition is responsible for their paralytic ataxia.
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PMID:Biochemical interaction of six OP delayed neurotoxicants with several neurotargets. 616 54

We report muscle biopsy abnormalities in four patients with a chronic cholestatic syndrome, low serum vitamin E levels, absent reflexes, mild limb weakness, ataxia, and sensory loss in arms and legs. Skeletal muscle fibers contained multiple autofluorescent inclusions that show strong acid phosphatase and esterase reactivity. By electronmicroscopy, the inclusions lying between myofibrils were membrane-bound dense bodies having characteristics of both lysosomes and lipopigment material. The material was similar to that observed in vitamin E-deficient animals and probably formed in response to disordered intracellular lipid peroxidation.
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PMID:Ultrastructural and histochemical abnormalities of skeletal muscle in patients with chronic vitamin E deficiency. 618 77

The delayed neurotoxic effects of tri-o-cresyl-phosphate (TOCP), O-methyl-O-(4-bromo-2,5-dichlorophenyl) phenylphosphonothioate (leptophos), and O-ethyl O-(4-nitrophenyl) phenylphosphonothioate (EPN) at 5, 5, and 1 mg/kg/day, respectively, on male sheep were studied during 6 months of daily oral treatment under field conditions. A vehicle-control group of sheep given corn oil (0.1 ml/kg/day) only was used for comparison. All sheep were killed 24 h after the 180th daily treatment. Blood, brain, spinal cord, and sciatic nerve tissues were taken for histological and/or biochemical examinations. The results indicated that leptophos induced severe ataxia and paralysis in sheep following about 4 months of treatment. TOCP produced either mild ataxia or lameness in two of four sheep during the last week of experiment. On the other hand, none of the EPN-treated sheep showed clinical signs of neurotoxicity during the course of the experiment at the dosage tested. These clinical results were supported by histological findings and also by biochemical results with neurotoxic esterase (NTE) measurements. In the case of leptophos-treated sheep, numerous prominent degenerative lesions of axons were observed in spinal cords and brains. Similar but somewhat less numerous lesions were noted in sheep treated with TOCP. No histological changes were observed in similar tissues taken from EPN-treated sheep. The results also indicated that, for chronic exposure to these neurotoxic organophosphorus compounds in sheep, a threshold in excess of 60-70% prolonged inhibition of brain NTE, or 50-60% inhibition of spinal cord NTE must be exceeded to initiate clinical and/or histological neurotoxic effects.
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PMID:Six-month daily treatment of sheep with neurotoxic organophosphorus compounds. 619 47

Eighteen-week-old mallard hens received 0, 10, 30, 90, or 270 ppm technical grade EPN (phenylphosphonothioic acid O-ethyl-O-4-nitrophenyl ester) in the diet for 90 days. Ataxia was first observed in the 270-ppm group after 16 days, in the 90-ppm group after 20 days, in the 30-ppm group after 38 days; 10 ppm failed to produce ataxia. By the end of 90 days all 6 birds in the 270-ppm group exhibited ataxia or paralysis whereas 5 of 6 birds in the 90-ppm group and 2 of 6 birds in the 30-ppm group were visibly affected. Treatment with 30 ppm or more resulted in a significant reduction in body weight. Brain neurotoxic esterase activity was inhibited by averages of 16, 69, 73, and 74% in the 10-, 30-, 90-, and 270-ppm groups, respectively. Brain acetylcholinesterase, plasma cholinesterase, and plasma alkaline phosphatase were significantly inhibited as well. Distinct histopathological effects were seen in the 30-, 90-, and 270-ppm groups which included demyelination and degeneration of axons of the spinal cord. Additional ducks were exposed in a similar manner to 60-, 270-, or 540-ppm leptophos (phosphonothioic acid O-4-bromo-2,5-dichlorophenyl-O-methylphenyl ester) which resulted in similar behavioral, biochemical, and histopathological alterations. These findings indicate that adult mallards are probably somewhat less sensitive than chickens to subchronic dietary exposure to organophosphorus insecticides that induce delayed neurotoxicity.
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PMID:Subchronic organophosphorus ester-induced delayed neurotoxicity in mallards. 620 72

Adult white leghorn chickens, ring-necked pheasants, mallards, bobwhites, and Japanese quail were administered single oral doses of tri-o-tolyl phosphate (TOTP) at levels of 125, 250, 500, and 1000 mg/kg body weight. Corn oil served as the vehicle control. At 24 h after dosing, half the birds from each group were killed for determination of whole-brain neurotoxic esterase (NTE) activity. The remaining birds were maintained for 21 d. Daily observations for the development of clinical signs typical of delayed neurotoxicity were begun 7 d after dosing and continued for the subsequent 14 d. In both the Japanese quail and bobwhite, all doses of TOTP resulted in NTE inhibition in excess of 70%, yet no birds of either species developed ataxia or paralysis. However, in the mallard none of the doses of TOTP caused inhibition of NTE activity greater than 61% nor resulted in the development of clinical signs. In the pheasant, all doses of TOTP caused at least a 70% inhibition of whole-brain NTE activity, yet only birds receiving 500 and 1000 mg/kg developed clinical signs. In the chicken, all TOTP doses caused inhibition of NTE in excess of 80%, and all doses resulted in clinical signs typical of delayed neurotoxicity.
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PMID:Differential sensitivity to the delayed neurotoxin tri-o-tolyl phosphate in several avian species. 662 Apr 21

We have studied four children (ages 6 to 17 years) with chronic cholestasis who developed a slowly progressive neuromuscular disease characterized by ataxia, dysmetria, areflexia, loss of vibratory sensation, and a variable ophthalmoplegia. Serum vitamin E concentrations were low in all patients prior to treatment (0.17-2.0 mg/g cholesterol, normal greater than 3 mg/g). Muscle histochemical studies showed prominent yellow autofluorescence, basophilic cytoplasmic inclusions which stain with esterase and acid phosphatase, and occasional necrotic fibers. Ultrastructural findings consisted of increased number and size of membrane-bound dense bodies (lysosomes), membranous whorls, and autophagic vacuoles. Intramuscular injections of all-rac-alpha-tocopherol (0.55-1.42 mg/kg per 24 hours based on individualized pharmacokinetic data) were required in three patients to achieve normal serum vitamin E values. High-dose (32 mg/kg per 24 hours) oral supplementation was effective in one patient. After normalization of serum vitamin E concentrations for 12 to 20 months, the neurologic disease has improved in all four patients.
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PMID:Progressive neuromuscular disease in children with chronic cholestasis and vitamin E deficiency: clinical and muscle biopsy findings and treatment with alpha-tocopherol. 695 72


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