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Query: UMLS:C0004134 (ataxia)
 15,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The neurotoxic effects of single subcutaneous injections of 1000 mg triphenyl phosphite (TPP)/kg body weight were investigated in White Leghorn hens. At 7 days postexposure, birds began to show signs of mild to moderate ataxia that progressed to severe ataxia and paralysis at 21 days. Inhibition of whole brain neuropathy target esterase was 85% at 48 hr and 73% by 21 days postexposure. After postexposure periods of 7, 14, and 21 days, hens were killed and their brains and spinal cords were examined for degenerating axons and terminals using the Fink-Heimer silver impregnation method. A small amount of degeneration was noted at 7 days. By 21 days, dense degeneration was noted in the spinal gray matter and funiculi. Degeneration was also present in the granular cell layer of cerebellar folia I-VI and in nuclei and fiber tracts of the medulla. Moderate to dense degeneration was also seen in several forebrain and midbrain areas including the paleostriatum, ansa lenticularis, the dorso-intermediate thalamic nucleus, lateral spiriform, pedunculopontine tegmental, and lateral mesencephalic nuclei and in the deeper layers of the optic tectum. These results indicate that, in addition to affecting the spinal cord and brainstem, exposure to TPP also damages higher order centers responsible for processing and integrating sensorimotor, visual, and auditory information.
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PMID:Neuropathological effects of triphenyl phosphite on the central nervous system of the hen (Gallus domesticus). 160 Dec 12

A disorder of central nervous white matter in Norwegian-bred silver foxes is described from the case histories of 21 clinically affected foxes. The main presenting sign of this disorder was caudal limb ataxia, which appeared between 2 1/2 and 4 months of age and progressed over the next 4-8 weeks. Only four affected foxes were allowed to live beyond this period, but they showed moderate to marked improvement. Light microscopic examination of specimens from 16 affected foxes necropsied between 3 1/2 and 6 1/2 months of age revealed lesions that were restricted to the white matter of brain and spinal cord. The lesions were characterized by a symmetrical spongy change with vacuoles of varying sizes and included significant myelin deficiency. There was a relative preservation of axons and nerve cells and no significant inflammation or vascular reaction. An astrocytic hypertrophy was usually associated with the spongy change. Ultrastructural examination of central nervous tissue from two, perfusion-fixed, 6-month-old foxes showed intramyelin vacuoles resulting from splitting of the myelin lamellae at the intraperiod line and was interpreted as indicating myelin edema. Expanded extracellular spaces and watery astrocytic processes also contributed to the vacuolar appearance. Astrocytic processes in affected areas were hypertrophic and contained abundant filaments. Although the 16 silver foxes had severe clinical signs, their lesions had features in common with the juvenile form of Canavan's disease in children and a spongy degeneration reported in Labrador Retrievers; however, the clinical course in the foxes was not uniformly progressive.
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PMID:Spongy degeneration of white matter in the central nervous system of silver foxes (Vulpes vulpes). 219 90

This paper examines the topography of neuronal degeneration in the central nervous system of the dystonia musculorum (dt) mutant mouse, revealed by selective silver impregnation, specific histochemical staining and electron microscopy. Neuronal lesions have been observed exclusively in the spinal cord, the medulla and the anterior lobe of the vermis. In the spinal cord, axonal degeneration was maximal among large and medium-sized primary sensory fibers, whereas thin caliber primary afferents were unaffected, with the exception of those containing acid phosphatase activity. In regions of laminae VI to VIII that receive numerous degenerative primary afferents, neurons undergoing different phases of degeneration (chromatolysis, lipid accumulation, dark shrunken necrosis) were constantly found. Most of the latter belonged to spinocerebellar neurons, owing to the presence of fiber degeneration in both spinocerebellar tracts and mossy fiber degeneration in the anterior vermal lobe. In the medulla only axonal degeneration was observed and was confined to three fiber systems: the dorsal column pathway, the sensory trigeminal fibers (both from the trigeminal ganglion and from the mesencephalic trigeminal nucleus), and the spinocerebellar fibers entering the cerebellum through the inferior and superior cerebellar peduncles. This study also suggests a simple pathophysiological mechanism for the onset and the progression of the degeneration: dystonic gene action would affect perinatally specific classes of sensory receptors, producing the degeneration of the nerve terminals and, progressively, the cell death of the sensory ganglion cells at their origin. This retrograde death, which results in the massive and early deafferentation of spinocerebellar neurons, would provoke, trans-neuronally, the impairment of these second order sensory neurons and the progressive degeneration of the spinocerebellar system. The close resemblance of the neuropathology of the mutant mouse to Friedreich's ataxia (the commonest form of human degenerative ataxic disorders) allows one to suppose that the dystonic mouse may be an optimal animal model for studying the genetic basis and the pathophysiological mechanisms of this form of human ataxia.
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PMID:Pathologic changes in the CNS of dystonia musculorum mutant mouse: an animal model for human spinocerebellar ataxia. 321

This histochemical study examined the effects of chronic methylmercury (MeHg) intoxication on the motor and sensory innervation of extensor digitorum longus muscles. Light microscopic examination of silver-stained axons in the intramuscular nerve bundles of MeHg-treated rats showed Wallerian-like degeneration and a reduction in the number of nerve fibers. Disrupted axons were predominantly sensory because 22.2% of spindle afferents (Ia) and 90.0% of Golgi tendon organ (Ib) sensory fibers were completely degenerated whereas less than 1% of motor endings were totally destroyed. Partial disruption occurred in the cholinesterase and motor terminals of 13.7% of endplates. Our results demonstrated greater vulnerability of sensory nerves than of motor nerves to MeHg-induced degeneration. Thus, the abnormal reflexes, ataxia, and muscle weakness following MeHg poisoning appear related to reduction of proprioceptive feedback from muscles and tendons in addition to the documented lesions in the central nervous system.
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PMID:Effects of methylmercury on the motor and sensory innervation of the rat extensor digitorum longus muscle. 358 15

The silver salt of 2-metanilamido-5-chloropyrimidine (AgMCP) and the sodium, amminosilver and trimethylphosphite-silver salts of 3',5'-dichlorobenzenesulfonanilide (NaDBS, AgNH3DBS and AgP(OCH3)3DBS were synthesized as possible antibiotic of antiparasitic drugs. All the organosilver compounds were extremely water-insoluble. For animal studies these, and other reference compounds, were given as fine suspensions in an Emulphor-safflower oil mixture. The ip LD50's in mice in mmol/kg were: 1.67 for NaDBS, 0.22 for silver acetate (AgAc), 0.15 for AgP(OCH3)3DBS, 0.13 for AgMCP and 0.10 for AgNH3DBS. When given by mouth, 15 mmol AgAc/kg produced a high mortality, but none of the organosilver compounds caused death in maximal doses (1.9 to 2.6 mmol/kg) that could be given based on considerations of total volume and stability of the suspension. All the silver compounds, including AgAc, produced a similar toxic syndrome with initial hyperexcitability, ataxia, central nervous depression, labored breathing, loss of righting reflex and death. Most deaths occurred between 12 and 24 hours after dosing. In contrast, animals given NaDBS often died within 3 hours although the major signs were very similar to those produced by the silver compounds. When given ip as a single dose 30 minutes after AgAc, D-penicillamine was effective in reducing mortality, but it had no effect on the mortality of the organosilver compounds. Histological studies revealed similar patterns of silver deposition, especially in the liver and kidneys, at 6, 18 and 24 hours after the organosilver compounds and after AgAc. We conclude that the presence of silver contributes significantly to the acute toxicity of these sulfonamides although they may dissociate free silver less readily than does AgAc.
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PMID:Acute toxicity of some silver salts of sulfonamides in mice and the efficacy of penicillamine in silver. 662 59

The neurotoxic effects of single oral doses of tri-ortho-tolyl phosphate (TOTP) (500 mg/kg body weight) or single subcutaneous injections of triphenyl phosphite (TPP) (62.5-500 mg/kg body weight) were investigated in the Japanese quail (Coturnix coturnix japonica). Oral doses of TOTP resulted in no detectable clinical signs while injections of TPP resulted in mild ataxia to severe paralysis depending upon the dosage level. At 24 hr postdosing, whole-brain activity of neuropathy target esterase (NTE) was inhibited by 90% in birds exposed to TOTP and by 11-87% in birds injected with TPP. Oral doses of TOTP resulted in only sparse Fink-Heimer silver-impregnated degeneration in the white matter of the cerebellum with no degeneration noted in any other region of the brain. Injections of TPP resulted in widespread degeneration in large numbers of brainstem nuclei and tracts and in all cerebellar foliae and deep nuclei. These results indicate that the Japanese quail responds differentially to exposure to TOTP and TPP. Oral doses of TOTP do not result in clinical signs or in significant amounts of degeneration in the brain even though NTE activity is inhibited by 90%. In contrast, injections of TPP at higher dosage levels yield severe clinical signs, widespread axonal and terminal degeneration in the CNS, and significant inhibition of NTE activity. This sharp dichotomy in relative sensitivity to TOTP and TPP in the Japanese quail suggests that each compound may have its own unique effect on CNS structure and function. In addition, the relationship between levels of NTE inhibition and the onset of clinical signs or neuropathology remains unclear.
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PMID:Organophosphorus-induced delayed neurotoxicity: a comparative study of the effects of tri-ortho-tolyl phosphate and triphenyl phosphite on the central nervous system of the Japanese quail. 760 44

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

To date, eight neurodegenerative diseases, including Huntington's disease, dentatorubral-pallidoluysian atrophy, spinal and bulbar muscular atrophy, and spinocerebellar ataxia (SCA) types 1, 2, 3, 6, and 7, have been proven to be caused by an expanded trinucleotide repeat (CAG)n located within a specific gene for each of these diseases. Except in SCA 6, the CAG repeat is present in approximately 7 to 35 copies in the normal population, whereas patients have CAG expansions of 40 to approximately 75 repeats. Sizing of the repeat length enables molecular diagnosis in affected patients and presymptomatic persons carrying a mutated allele. A molecular protocol for the diagnosis of these diseases was developed based on polymerase chain reaction, denaturing polyacrylamide gel electrophoresis and staining with silver nitrate, and adapted to each disease. This simple and rapid method gives a sensitivity of detection equal to current procedures but avoids isotopic manipulations. Therefore, shorter turnaround time, decreased cost per sample, and simplified screening of these neurodegenerative diseases by PCR-based assays may be attainable using this protocol.
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PMID:Simple nonisotopic assays for detection of (CAG)n repeats expansions associated with seven neurodegenerative disorders. 983 74

Abou-Donia et al. (in Toxicologist, Vol. 30, 1996) have reported that repeated oral administration of the organo-phosphorus compound triphenyl phosphine (TPPn) to the domestic chicken results in neuropathological changes in the spinal cord and peripheral nerves, accompanied by ataxia and paralysis. This study also noted that single doses of TPPn resulted in no inhibition of the enzymes neuropathy target esterase (NTE) and acetylcholinesterase (AChE). We undertook the present study to determine the biochemical, neuropathological, and clinical effects of single doses of TPPn in the European ferret, a mammalian species shown to be susceptible to organophosphorus-induced neurotoxicity. Eight 12-week-old ferrets were each injected subcutaneously with either 250 mg TPPn/kg bw or 500 mg TPPn/kg bw, or with the peanut oil/ethyl ether vehicle. Twenty-four h after dosing, the brains of 5 animals from each dose group were examined for NTE and AChE activities. The remaining 3 animals in each group were observed for 6 days for the development of clinical signs, after which their brains were processed for the presence of axonal degeneration using the Fink-Heimer silver impregnation method. Single injections of TPPn had no effect on the activities of whole-brain NTE or AChE 24 h after injection. The animals observed for clinical signs showed increasing trunk and hindlimb ataxia beginning 4 days after injection, culminating in fore-and hindlimb paralysis 6 days after injection. All brains exposed to either dose of TPPn showed widespread axonal degeneration extending from the brainstem and cerebellum into midbrain and forebrain areas. The results of this study support the hypothesis that TPPn-induced neurotoxicity is a separate and distinct form of organophosphorus-induced neurotoxicity not dependent on NTE inhibition, and therefore not a variant of organophosphorus-induced delayed neurotoxicity (OPIDN).
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PMID:Organophosphorus-induced neurotoxicity in the absence of neuropathy target esterase inhibition: the effects of triphenyl phosphine in the European ferret. 1036 44

We report an 84-year-old woman with progressive mental deterioration. She was well until January 1994, when she was 80 years of the age. At that time she developed a delusional ideation, in that she stated that she would be killed by her fellow members of the society for elderly, in which she was belonging. At times, she closed the shutter of her house saying that a stranger was wandering outside of her house. In 1995, she could not identify the face of her son's wife. When she went out for shopping, she lost her way to the home. She prowled about in and out of her home. In 1996, she had to be admitted to a nursing home, where quarrelled with other patients and behaved violently. She was admitted to the neurology service of Hatsuishi Hospital on November 20th, 1997. Family history revealed that her mother was said to be demented. On admission, she was alert and behaved in a good manner. She was disoriented to the time and unable to do serial 7. Her memory was very poor. She did not show aphasia or apraxia. Cranial nerves appeared to be intact. She showed no weakness or muscle atrophy. Gait was normal for her age. Plastic rigidity was noted in four limbs more on the right side. No ataxia was noted. Deep tendon reflexes were exaggerated, however, no Babinski sign was noted. Sensory examination was intact. Her hospital course was characterized by the development of progressive gait disturbance, violent behaviour, and prowling around. On November 30th, 1998, she fell down and suffered from a fracture in the neck of her femur. Although replacement of the femur head was performed, she became unable to walk after this episode. Her mental functions deteriorated further. She developed pneumonia and expired on February 2, 1999. She was discussed in a neurological CPC and the chief discussant arrived at a conclusion that the patient probably had diffuse Lewy body disease, because of the combination of dementia and parkinsonism. Other possibilities discussed in the CPC included Pick's disease, frontotemporal dementia and parkinsonism, and Alzheimer's disease. Post-mortem examination revealed moderate atrophy in the frontal and temporal cortices. Microscopic examination showed atrophy and gliosis in the hippocampus. Many diffuse plaque and neuritic plaques were seen in the frontal cortex by methenamine silver staining. Neurofibrillary tangles were also found. The Meynert nucleus was preserved. The putamen and the substantia nigra were also intact. Pathologic diagnosis was consistent with Alzheimer's disease.
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PMID:[An 84-year-old woman with progressive mental deterioration and abnormal behavior]. 1127 7


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