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Query: UMLS:C0040822 (tremor)
 18,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The clinical and pathologic features of a male patient with generalized glutathione deficiency and pyroglutamic aciduria are presented. The patient died at the age of 28 years. He was mentally retarded from infancy and developed progressive tremor, retardation of movement, and ataxia as from the age of 16. Neuropathologic examination of the brain disclosed a selective atrophy of the granule cell layer of the cerebellum and focal lesions in the visual cortex and the thalamus. The type and distribution of the lesions resembled those seen after mercury intoxication. However, in our patient the damage was probably caused by the lack of protection of glutathione against oxidative damage in the brain. Possible treatment of this rare metabolic disorder might include external supply of an antioxidant, e.g., a thiol capable of penetrating the blood brain barrier.
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PMID:The cerebral lesions in a patient with generalized glutathione deficiency and pyroglutamic aciduria (5-oxoprolinuria). 744 86

Neurological and neurophysiological examinations were conducted in 77 former chloralkali workers previously exposed to mercury vapour and 53 referents. The exposure had ceased on average 12.3 years prior to the study. There was a higher prevalence of reduced distal sensation (13.0% vs 1.9%), postural tremor (18.2% vs 7.5%) and impaired coordination (10.4% vs 1.9%) among the exposed subjects as compared to the referents. Abnormal Romberg's test (6.5% vs 0%) and line walking (7.8% vs 0%) were also more prevalent. The first negative peak in visual evoked response (N75) was bilaterally prolonged, and the median motor (55.9 m/s vs 58.0 m/s) and sensory nerve conduction velocity (55.6 m/s vs 59.0 m/s) were slightly reduced among the highly exposed subjects. The results indicate that slight neurological abnormalities, which in most cases could not be classified as disease, may persist many years after exposure cessation.
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PMID:A neurological and neurophysiological study of chloralkali workers previously exposed to mercury vapour. 811 45

We studied the relative etiologic importance upon the development of Parkinson's disease (PD) of occupational exposure to herbicides and other compounds, ionizing radiation exposure, family history of PD and essential tremor, smoking, and history of various viral and other medical conditions. We identified patients (n = 130) with neurologist-confirmed idiopathic PD through contacts with Calgary general hospitals, long-term care facilities, neurologists, the Movement Disorder Clinic, and the Parkinson's Society of Southern Alberta, and selected two matched (by sex and age +/- 2.5 years) community controls for each case by random digit dialing. We obtained lifetime work, chemical, radiation, medical, and smoking exposure histories and family histories of PD and essential tremor by personal interviews, and analyzed the data using conditional logistic regression for matched sets. After controlling for potential confounding and interaction between the exposure variables, using multivariate statistical methods, having a family history of PD was the strongest predictor of PD risk, followed by head trauma and then occupational herbicide use. Cases and controls did not differ in their previous exposures to smoking or ionizing radiation; family history of essential tremor; work-related contact with aluminum, carbon monoxide, cyanide, manganese, mercury, or mineral oils; or history of arteriosclerosis, chicken pox, encephalitis, hypertension, hypotension, measles, mumps, rubella, or Spanish flu. These results support the hypothesis of a multifactorial etiology for PD, probably involving genetic, environmental, trauma, and possibly other factors.
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PMID:Parkinson's disease: a test of the multifactorial etiologic hypothesis. 817 May 64

Extrapyramidal signs are frequently observed in toxic diseases due to environmental and industrial chemical substances. The predominant manifestations are Parkinsonism and less frequently tremor. Parkinsonism has been described among the toxic diseases due to carbon monoxide, hydrogen sulfide, and hydrogen cyanide. In these diseases, Parkinsonism used to appear in the recovery stage from coma in the severe cases. This was also true in methyl alcohol poisoning. The extrapyramidal signs are usually symmetrical. Akinesia and rigidity are main features. Tremor is absent or mild. Levodopa and the other antiparkinsonian drugs are not so effective. Brain CT studies have revealed symmetrical low density areas in the globus pallidus and putamen. On the other hand, postural tremor is main neurological findings in the poisonings by inorganic mercury and tetraethyl lead. In general, tremor in the toxic disease is reported to be self-limited.
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PMID:[Extrapyramidal syndrome induced by chemical substances]. 827 73

A 42 year old male, while repairing a sphygmomanometer, intentionally ingested an estimated 3 kg (220 mL) of metallic mercury. During admission, only tremor, irritability, forgetfulness and fatigue were noted. There were no obvious gastrointestinal or hepatic complications. Blood and urine mercury levels were significantly elevated. Most of the metallic mercury was cleared from the gut within 10 days. A few months later, hepatic dysfunction with jaundice developed. Serial investigations did not suggest a viral etiology or alcoholism. Liver function tests and blood and urine mercury levels returned to normal over the next 10 months. The observation suggests that massive and prolonged retention of metallic mercury may facilitate the conversion of metallic, elemental mercury to divalent mercury and its subsequent absorption with development of hepatic dysfunction.
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PMID:Massive oral ingestion of elemental mercury. 835 25

A cross sectional study of aspects of their neurology was carried out on 77 chloralkali workers previously exposed to mercury (Hg) vapour and compared with 53 age matched referents. The chloralkali workers had been exposed for an average of 7.9 years at a concentration of 59 micrograms Hg/m3 in the working atmosphere. The individual mean urinary concentration of Hg for each year of exposure was 531 nmol Hg/1. On average the exposure had ceased 12.3 years before the examinations. Both the median sensory nerve conduction velocity and the amplitude of the sural nerve were associated with measures of cumulative exposure to Hg. An association was also found between years since first exposure to Hg and aspects of the visual evoked response. Previously exposed subjects with postural tremor or impaired coordination also had alterations in visual evoked response. These results may indicate an effect of previous exposure to mercury vapour on the nervous system, possibly in the visual pathway, cerebellum, and the peripheral sensory nerves.
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PMID:Relation between exposure related indices and neurological and neurophysiological effects in workers previously exposed to mercury vapour. 839 61

Early signs of alterations in renal and neurological functions were studied in three groups of workers who were exposed to different levels of mercury that were below the current biological exposure index of 35 microg/g creatinine. There were no differences among the three study groups with respect to either motor nerve conduction velocity or tremor frequency spectra of physiological tremors. Also, no significant correlations were found between the results of the neurological tests and any of the present or historical biological monitoring data. In contrast, N-acetyl-beta-D-glucosaminidase was increased significantly in the group with the higher exposure, compared with either the lower-exposure or control groups. N-acetyl-beta-D-glucosaminidase was correlated strongly with mercury concentration in urine and was correlated weakly with historical biological monitoring data; however, there was no correlation with duration of exposure. These results suggest that after exposure to mercury at levels below the biological exposure index, a transient increase in N-acetyl-beta-D-glucosaminidase can be observed, but is not an early indicator of developing renal dysfunction.
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PMID:Effects of exposure to elemental mercury on the nervous system and the kidneys of workers producing natural gas. 863 60

The authors carried out neurological examination, visual evoked potentials (VEP) examination, and electromyography (EMG) on 77 workers, aged 21-61 yrs, who were exposed occupationally to Hgo vapors for 1-20 yrs (mean 9 yrs). The mean air-borne concentration of Hgo was 0.25 mg/m3 (range 0.02-1.00 mg m3), and the mean Hg urinary concentration was 0.21 mg/l (range 0.02-0.77 mg/l). Symptoms of erethism (generally accepted as a typical sign of micromercurialism) were reported in about 80% of the workers. The static tremor of fingers (in 25%), and the absence of ankle jerk (in 20%) were the most frequently observed signs. VEP was abnormal in 39 workers (51%), but in 25 of those, an explanation for this finding could be found in their history and/or neurological status. In the 14 remaining cases, the connection with exposure to Hgo has been considered. A polyneuropathic pattern of EMG abnormality was found in 5 workers, an isolated EMG abnormality of the sural nerve in 13 workers. In 9 workers no other obvious cause for EMG abnormality was found but exposure to mercury. The association of EMG abnormality (especially decreased conduction velocity of the sural nerve) with VEP abnormality (especially shortening of latency) seems to be a relatively characteristic electrophysiological pattern in persons exposed to mercury vapors, suggesting an incipient, or subclinical damage to the nervous system.
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PMID:Neurological and electrophysiological examination on workers exposed to mercury vapors. 878 30

Clinical and quantitative studies in which tremor was used to evaluate the effect of chronic exposure to organic and inorganic mercury in human subjects during the last 20 years were identified in MEDLINE and BIOLOGICAL ABSTRACTS. In the selected studies, methods varied widely by types of transducers used, anatomical locations of tremor testing, tasks executed by the subjects, types of tremor recorded and durations of trials. Measurements of tremor in these studies also varied by frequency, amplitude, waveform and reproducibility. Typically measures of variability were not included. Results obtained depended heavily on the methods and analyses used. We suggest that, although many contradictions and discrepancies have been noted in these studies, tremor can probably be used to measure the effect of chronic mercury exposure. This would involve more rigorous and uniform recording procedures and analyses. Specific suggestions proposed include: realizing the limitations of accelerometric data; considering the effect of weight on the tested limb; controlling recording conditions; selecting samples more carefully; recording other physiological variables besides tremor; using tasks and manoeuvres that unmask subclinical abnormalities in tremor; reporting frequency, amplitude, waveform and variability of tremor; understanding the limitations of power spectra analysis; separating tremor characteristics according to types of mercury exposure; and considering supraspinal influences that both vision and voluntary movements have on tremor.
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PMID:Can tremor be used to measure the effect of chronic mercury exposure in human subjects? 878 32

A 47 year old female dentist suffered from hemiparkinsonism which had started eighteen months earlier and was manifested mainly by resting tremor and cogwheel rigidity. A baseline quantitative urinary mercury excretion was 46 micrograms/day. The patient was treated with chelating agent d-penicillamine for a week. Chelation therapy resulted in clinical improvement of parkinsonism and in dynamic changes in daily urinary mercury excretion with a prompt increase to 79 micrograms/day, a subsequent decline followed by increase in the mercury urinary excretion. After a week chelation therapy was stopped. During a follow-up period of five years, the neurological status remained unchanged after the initial penicillamine-induced improvement. This case may be evidence, therefore, of a rare clinical variant of elemental mercury intoxication associated with parkinsonism, in the absence of most classical neuropsychiatric signs of chronic mercurialism.
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PMID:The enigma of parkinsonism in chronic borderline mercury intoxication, resolved by challenge with penicillamine. 878 40


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