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)

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 concentration were low in all patients prior to treatment. Muscle histochemical studies in all four patients showed autofluorescent basophilic esterase and acid phosphatase-positive cytoplasmic inclusions and occasional necrotic fibers. These distinctive muscle changes are similar to those described in vitamin E-deficient animals. Intramuscular injections of alpha tocopherol were required in three patients to achieve normal serum vitamin E values. High-dose oral supplementation was effective in one patient. After normalization of serum vitamin E concentrations for six to 14 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: diagnosis and treatment with alpha tocopherol. 705 16

O-n-Propyl O-(2-propynyl) phenylphosphonate (NIA-16388), which has been recommended for use as insecticide synergist, was synthesized and tested for acute and neurotoxicities in hens. The 24-h LD50 value of this compound in the hen was found to be about 340 mg/kg. Hens treated with this compound at 400 mg/kg with atropine sulfate as an antidote developed clear clinical signs of delayed neurotoxicity 12-17 d after single oral treatment. The signs of neurotoxicity gradually progressed from ataxia through paralysis. Biochemical tests indicated that at the tested dose level of this compound, the level of hen-brain neurotoxic esterase (NTE) was inhibited in vivo to less than 10% of the normal level 1 d after treatment. These clinical and biochemical signs of neurotoxicity are supported by histopathological findings. Degenerative lesions of axons were observed in the NIA-treated group of hens. The lesions in the spinal cord were seen most frequently and most prominently in the lateral columns, although they sometimes were observed in other areas, e.g., in the anterior columns (especially in thoracic and lumbar sections). Generally, the lesions were more apparent in the longitudinal sections than in the cross-sections. Two other phenylphosphonate derivatives, O-ethyl S-benzyl phenylphosphonothioate (ESBP) and O-methyl O-(4-benzylidenylphenylhydrazone) phenylphosphonothioate, were also synthesized and tested for neurotoxicity to hens. The LD50 values for these two compounds in the hen were more than 1000 mg/kg. No signs of delayed neuropathy were detected in hens given either ESBP or the hydrazone compound at single oral doses of 1000 mg/kg.
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PMID:Delayed neuropathy in hen by the insecticide synergist O-n-propyl O-(2-propynyl) phenylphosphonate (NIA-16388) and other phenylphosphonate esters. 716 38

Chlorpyrifos (CPS; O,O-diethyl 3,5,6-trichloro-2-pyridyl phosphorothionate; Dursban) is a widely used broad-spectrum organophosphorus (OP) insecticide. Because some OP compounds can cause a sensory-motor distal axonopathy called OP compound-induced delayed neurotoxicity (OPIDN), CPS has been evaluated for this paralytic effect. Early studies of the neurotoxicity of CPS in young and adult hens reported reversible leg weakness but failed to detect OPIDN. More recently, a human case of mild OPIDN was reported to result from ingestion of a massive dose (about 300 mg/kg) in a suicide attempt. Subsequent experiments in adult hens (the currently accepted animal model of choice for studies of OPIDN) showed that doses of CPS in excess of the LD50 in atropine-treated animals inhibited brain neurotoxic esterase (NTE) and produced mild to moderate ataxia. Considering the extensive use of CPS and its demonstrated potential for causing OPIDN at supralethal doses, additional data are needed to enable quantitative estimates to be made of the neuropathic risk of this compound. Previous work has shown that the ability of OP insecticides to cause acute cholinergic toxicity versus OPIDN can be predicted from their relative tendency to inhibit the intended target, acetylcholinesterase (AChE), versus the putative neuropathic target, NTE, in brain tissue. The present study was designed to clarify the magnitude of neuropathic risk associated with CPS exposures by measuring hen brain AChE and NTE inhibition following dosing in vivo and determining the bimolecular rate constant of inhibition (ki) for each enzyme by the active metabolite, CPS oxon (CPO), in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Inhibition of hen brain acetylcholinesterase and neurotoxic esterase by chlorpyrifos in vivo and kinetics of inhibition by chlorpyrifos oxon in vitro: application to assessment of neuropathic risk. 768 90

Hens treated with Mipafox (10 mg/kg, sc), sarin (50 micrograms/kg, sc) or parathion (1 mg/kg, sc) daily for 10 days exhibited severe, moderate and no ataxia respectively on 14th day after the start of exposure. The neurotoxic esterase (NTE) activity was significantly inhibited in the brain, spinal cord and platelets of hens treated with mipafox or sarin whereas no change was noticed with parathion treatment. All three compounds significantly inhibited acetylcholinesterase (AChE) activity in the platelets. Spinal cord of hens treated with mipafox, sarin or parathion showed axonal degeneration heavy, moderate and none respectively. It is concluded that repeated administration of equitoxic doses of mipafox, sarin and parathion to hens are marked, moderate and non-delayed neurotoxic respectively.
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PMID:A comparative study of delayed neurotoxicity in hens following repeated administration of organophosphorus compounds. 770 69

Delayed neurotoxicity of sarin in mice after repeated inhalation exposure has been studied. Female mice exposed to atmospheric sarin (5 mg m-3 for 20 min) daily for 10 days developed muscular weakness of the limbs and slight ataxia on the 14th day after the start of the exposure. These changes were accompanied by significant inhibition of neurotoxic esterase (NTE) activity in the brain, spinal cord and platelets. Histopathology of the spinal cord of exposed animals showed focal axonal degeneration. These changes were comparatively less than in animals treated with the neurotoxic organophosphate, mipafox. Results from this study indicate that sarin may induce delayed neurotoxic effects in mice following repeated inhalation exposure.
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PMID:Delayed neurotoxic effect of sarin in mice after repeated inhalation exposure. 848 13

In order to validate a rodent biochemical model of delayed neurotoxicity of organophosphates (OP) inhibition of rat and hen brain neurotoxic esterase (NTE) by some dichlorovinyl phosphates and phosphonates was studied in vitro and in vivo. It was shown that compounds investigated exhibited the similar inhibitory potency to NTE from both species in vitro, in addition rat and hen NTE showed the same sensitivity to variation of the structure of OP inhibitors. A good correlation was found between pI50 estimated with enzymes from rat and hen trains: r2 = 0.951, n = 18, p < or = 0.05. NTE activities were also measured in rat and hen brains after acute administration of various dosages of potent axonopathic compound dipropyldichlorovinyl phosphate. The results obtained indicate that difference in species susceptibility to neurotoxic action of OP, in particular the absence of ataxia in rats, is not caused by difference in target enzyme sensitivity to axonopathic organophosphates.
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PMID:[A comparative study of the interaction of phosphoric acid dichlorovinyl esters with a neurotoxic esterase from the brain of hens and rats]. 877 79

Sensitivity of in-life parameters, biochemical endpoints, and susceptibility of various areas of the chicken nervous system to delayed neuropathy induced by tri-orthocresyl phosphate (TOCP) was assessed. Groups of hens were exposed to a single oral dose of TOCP of 0, 50, 200 or 500 mg/kg and the animals observed for 21 days. Perfusion fixed, paraffin embedded tissue sections were stained with Bodian's silver and Luxol blue and semi-thin epoxy sections with toluidine blue. Sciatic and tibial nerves, lumbosacral, midthoracic, and upper cervical spinal cord, medulla oblongata and cerebellum were examined using a semiquantitative scoring system. In pair-dosed hens inhibition of brain and spinal cord neurotoxic esterase (NTE) and cholinesterase and of plasma and erythrocyte cholinesterases was determined 24 hr and 48 hr after administration. At all dose levels NTE in brain and spinal cord and plasma cholinesterase was inhibited markedly. Quantitative inhibition of NTE was seen also in absence of neuropathy. Ataxia and body weight loss occurred in high-dose animals only, while dose-related neuropathy was seen in the distal tibial nerve, medulla oblongata and cerebellum. Ataxia was correlated best with neuropathy in peripheral nerves while degeneration of nerve fibers in the cerebellum, seen best in mid-longitudinal sections, was the most sensitive histological indicator of TOCP-induced delayed neuropathy. The particular susceptibility of spinocerebellar neurons was recognized long ago, but often has been neglected in delayed neurotoxicity studies and respective guidelines. Optimal sensitivity of toxicity tests is a prerequisite for risk assessment, can be cost efficient, and nowadays should be a main interest of animal welfare in order to reduce animals' suffering. Based on these data, determination of NTE inhibition together with histopathological examination of longitudinal sections of distal tibial nerves, mid-longitudinal sections of rostral cerebellum and cross sections of upper cervical spinal cord represents an optimally sensitive and cost efficient test requirement.
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PMID:Susceptibility of various areas of the nervous system of hens to TOCP-induced delayed neuropathy. 908 80

Clinical manifestations of mild organophosphorus compound-induced delayed neurotoxicity (OPIDN) produced by diisopropylphosphorofluoridate (DFP) in adult hens are potentiated by posttreatment with phenylmethanesulfonyl fluoride (PMSF). The purpose of this study was to assess whether potentiation of mild OPIDN produces a pattern of axonal lesions in the central and peripheral nervous system similar to that seen in severe OPIDN. Groups of 6 hens each were given the following priming/challenge doses sc at 0 and 4 h, respectively: 0.20 ml/kg corn oil/0.50 ml/kg glycerol formal (GF) (control); 0.50 mg/kg DFP/GF (low-dose DFP); 0.50 mg/kg DFP/60 mg/kg PMSF (potentiated DFP); 60 mg/kg PMSF/GF (PMSF alone); 60 mg/kg PMSF/1.5 mg/kg DFP (protected DFP); and 1.5 mg/kg DFP/GF (high-dose DFP). Two hens from each group were used to assay brain neurotoxic esterase (NTE) 24 h after the challenge dose, and the remaining hens were scored for deficits in walking, standing, and perching ability on d 18. Three hens from each group were perfusion-fixed on d 22 and neural tissues were prepared for histologic evaluation. DFP and/or PMSF caused > 88% brain NTE inhibition in all treated groups, compared to control. Protected DFP yielded no clinical deficits and a distribution and frequency of axonal lesions similar to control. PMSF alone produced a small increase in the frequency of lesions in the cervical spinal cord and peripheral nerves compared to control. Low-dose DFP caused minimal ataxia and increased frequency of axonal lesions in dorsal and lateral cervical spinal cord, ventral lumbar spinal cord, and inferior cerebellar peduncles (ICP) compared to control. Potentiated DFP and high-dose DFP produced maximal ataxia and essentially identical increases in the frequency of lesions in dorsal and ventral thoracic spinal cord, lateral lumbar spinal cord, and peripheral nerves compared to low-dose DFP. The results indicate that PMSF potentiation of mild OPIDN induced in adult hens by low-dose DFP results in an overall pattern of axonal degeneration like that produced by a threefold higher dose of DFP alone, and support the hypothesis that potentiation causes an increase in the frequency of axonal lesions in central and peripheral loci normally affected by OPIDN.
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PMID:Potentiation of organophosphorus compound-induced delayed neurotoxicity (OPIDN) in the central and peripheral nervous system of the adult hen: distribution of axonal lesions. 924 29

Neuropathy target esterase (neurotoxic esterase, NTE), a protein thought to be involved in the production of organophosphorus compound-induced delayed neurotoxicity (OPIDN), has been postulated to be a component of endogenous neuronal protein phosphorylation systems. The purpose of this work was to test this hypothesis as well as to investigate further the role of endogenous protein phosphorylation in toxic neuropathies. White Leghorn hens were dosed with the neuropathic compounds di-1-butyl-2,2-dichlorovinyl phosphate (dibutyl dichlorvos, DBDCV), tri-o-cresyl phosphate (TOCP), or acrylamide, and regions from brain were fractionated into axolemmal, synaptosomal, and microsomal preparations. Radiolabeling of NTE or endogenously phosphorylated proteins was carried out by incubation with [14C]-DFP or gamma-[32P]-ATP, respectively. Radiolabeled proteins were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and visualized by autoradiography. Relative amounts of phosphoproteins were quantified by densitometry of the autoradiographs. Changes in endogenous phosphorylation of a protein exhibiting the characteristics of NTE were not observed in these experiments. However, levels of a [32P]-labeled 50-kDa brainstem axolemmal protein were decreased significantly on d 15, but not on d 1, 3, 7, or 10 after dosing with 2.8 mg/kg DBDCV. Clinical signs of ataxia and histopathological findings of axonal degeneration in the spinocerebellar tracts of the brainstem were evident on d 10-15, and hens were unable to perch on a horizontal wooden rod from d 12 after dosing with DBDCV. The decrease in the 50-kDa phosphoprotein was not observed on d 15 after the production of clinically evident neuropathy with either 14 daily doses of 50 mg/kg acrylamide or with a single dose of 500 mg/kg TOCP. These results suggest that NTE is not an endogenously phosphorylated protein under the conditions of these experiments. However, an effect on endogenous phosphorylation limited to a 50-kDa axolemmal protein was selectively produced by treatment with a neuropathic dose of DBDCV that was in evidence only after clinical signs and histopathological findings of axonopathy were apparent.
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PMID:Brainstem axolemmal protein phosphorylation in vitro in hens dosed with di-1-butyl-2,2-dichlorovinyl phosphate. 1070 44

The neurotoxicity of organophosphorus compounds (OPs) including leptophos, TOCP and triphenyl phosphite and dithiocarbamate compounds were reviewed in this study. The major neurotoxicities of OPs were acute toxicity produced by the acetylcholine esterase (AChE) inhibiting action of OPs and delayed neurotoxicity produced by such OPs as leptophos and TOCP. The direct action of OP on the muscarinic and/or nicotinic acethylcholine receptors in the synaptic membranes have lately attracted attention in relation to acute toxicity. Delayed neurotoxicity is a delayed onset of prolonged locomotor ataxia resulting from a single or repeated exposure to an OP. Although neurotoxic esterase (NTE) inhibition might be related to the onset of organophosphate-induced delayed neurotoxicity (OPIDN), the precise mode of action is not yet clear. The effect of dithiocarbamates on the nervous system is also mentioned, because the compounds are currently suspected not only for neurotoxicity, but also as endocrine-disrupting chemicals. Although dithiocarbamates showed weak neurotoxicity in adult animals, we need to pay more attention to developmental neurotoxicity.
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PMID:[Neurotoxicity of organophosphorus and dithiocarbamate compounds]. 1263 69


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