Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027066 (myoclonus)
 4,275 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A patient is described with severe intention myoclonus which was made worse by treatment with L-Dopa and improved by clonazepam. Family history and examination of several siblings suggested the diagnosis of Huntington's disease. Subsequent to improvement of the myoclonus the patient appeared to have the rigid form of Huntington's disease. This case represents a unique expression for an otherwise well defined genetic abnormality. Stimulus activated myoclonus in a common feature of a number of disorders of the nervous system. Intention, or action myoclonus has been the subject of increasing interest because of its association with the syndrome of post-anoxic encephalopathy (1), although it may occur with other disorders as well. Many abnormal movements have been reported in Huntington's disease, but myoclonus is a relatively uncommon feature of this disorder and to our knowledge intention myoclonus has not been reported as a major symptom. We recently have evaluated a patient with disabling intention myoclonus and examined several members of his family who have typical Huntington's disease. We therefore report this case, a unique presentation of an otherwise well described movement disturbance.
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PMID:Intention myoclonus in Huntington's disease. 13 56

This review covers recent advances in a variety of dyskinesias. Introduction of new drugs for the treatment of myoclonus and sensory biofeedback therapy for focal dystonia are expanding our concepts of these types of movement disorders. Progress in the treatment of action myoclonus is especially noteworthy and has led to the implication of serotonin deficit in the pathophysiology of this syndrome. Knowledge of the biochemical pathology of Huntington's chorea has outpaced therapy for this disorder, but new forms of therapy have been proposed based on the chemical findings. Basic pharmacologic studies suggest pathophysiologic mechanisms for the syndrome known as tardive dyskinesia, but treatment is still far from ideal for this disorder. Other movement disorders with recent therapeutic advances include essential tremor and hemiballism. This review will cover only those dyskinesias in which new therapies have been advanced in the last few years. Aside from parkinsonism, which will not be discussed here, progress in the treatment of movement disorders has been slow, but steady. New drugs are being tested constantly, and the purpose of this review is to call attention to the ongoing evaluation in this field. Descriptions and etiologies for these dyskinesias are covered elsewhere (Fahn, 1976a) and therefore are not repeated here.
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PMID:New approaches in the management of hyperkinetic movement disorders. 30 60

An extrapyramidal disorder occurring in three generations of a family (only males) is described The clinical features were progressive dementia and extrapyramidal signs without choreiform hyperkinesia. The youngest patient (onset of disease at the age of 22 years) showed tremor, rigidity, ataxia, convulsions, and myoclonus. The neuropathologic findings were characterized by isolated symmetrical degeneration of the corpus striatum and diffuse cortical atrophy without affecting other cerebrospinal neuronal systems. The clinical features of this familial disorder and its relation to other types of familial striatal degeneration and to the juvenile form of Huntington's chorea are discussed.
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PMID:[Familial striatal degeneration (author's transl)]. 54 75

In contrast to juvenile rigid form of Huntington's disease (HD) in which myoclonus is often seen, only 5 patients with myoclonus complicating adult HD have been reported. We herein described an adult HD patient who suffered from severe action myoclonus leading to physical disability. To our knowledge, this is the first case report in Japan. The patient, a 32-year-old female with a family history of chorea, developed choreiform movements and mental changes since the age of 24. Subsequently her motor disability has been aggravated by distinctively different involuntary movements characterized by sudden, violent, continuous muscular contractions of four extremities on any attempts at movement. Examination revealed moderate dementia and chorea complicated by frequent myoclonic jerks involving upper and lower extremities in posture or during movement. A head CT scan and MRI revealed caudate atrophy. The myoclonus, as recorded by surface electromyography over the right arm consisted of 40-60 msec-synchronous semirhythmic bursts. The cortical component of SEP was enlarged and C reflex was also observed. Clonazepam (4 mg a day) was instituted with a pronounced reduction in myoclonus and a return to her previous level of daily life activity. Although myoclonic jerks are often recognized in juvenile patients with rigid form of HD, they have been considered to exert a minor influence on physical disability. By contrast, our present observation and review of literature suggest that myoclonus may lead to severe motor impairment in adult HD.
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PMID:[Action myoclonus in adult Huntington's disease]. 129 Nov 67

Animal data indicate that serotonin (5-HT) is a major neurotransmitter involved in the control of numerous central nervous system functions including mood, aggression, pain, anxiety, sleep, memory, eating behavior, addictive behavior, temperature control, endocrine regulation, and motor behavior. Moreover, there is evidence that abnormalities of 5-HT functions are related to the pathophysiology of diverse neurological conditions including Parkinson's disease, tardive dyskinesia, akathisia, dystonia, Huntington's disease, familial tremor, restless legs syndrome, myoclonus, Gilles de la Tourette's syndrome, multiple sclerosis, sleep disorders, and dementia. The psychiatric disorders of schizophrenia, mania, depression, aggressive and self-injurious behavior, obsessive compulsive disorder, seasonal affective disorder, substance abuse, hypersexuality, anxiety disorders, bulimia, childhood hyperactivity, and behavioral disorders in geriatric patients have been linked to impaired central 5-HT functions. Tryptophan, the natural amino acid precursor in 5-HT biosynthesis, increases 5-HT synthesis in the brain and, therefore, may stimulate 5-HT release and function. Since it is a natural constituent of the diet, tryptophan should have low toxicity and produce few side effects. Based on these advantages, dietary tryptophan supplementation has been used in the management of neuropsychiatric disorders with variable success. This review summarizes current clinical use of tryptophan supplementation in neuropsychiatric disorders.
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PMID:L-tryptophan in neuropsychiatric disorders: a review. 130 30

Two brothers with clinically definite adult Huntington's disease developed disabling myoclonus years after the first signs of the disease. Their electroencephalograms were consistent with a primary generalized epilepsy, although neither man had seizures. The myoclonus was controlled with valproic acid therapy.
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PMID:Myoclonus in adult Huntington's disease. 182 19

Hand muscle reflexes to stretch or electric stimulation of mixed nerves consist of two main components, the short latency reflex (SLR, M1) or Hoffmann reflex (HR) and the long latency reflex (LLR, M2). The SLR is most likely a spinal, monosynaptic reflex and all the evidence presently available supports a transcortical pathway of the LLR. Investigations in normal subjects demonstrate that the LLR is a reflex mediated by fast conducting muscle and cutaneous afferents. Group II muscle afferents do not significantly contribute to this reflex and it cannot be explained by repetitive excitation of spinal oligosynaptic pathways. These findings should not be uncritically generalized to other muscle groups, because the central and peripheral mechanisms apparently differ according to the body region and mode of stimulation. The LLR of hand muscles is most likely involved in skillful movements of the fingers. It is believed to assist rapid compensatory responses to unexpected disturbances. In addition to the main component of the LLR, which is called LLR II, the study of electrically elicited thenar reflexes following stimulation of the median nerve disclosed further LLR components, the LLR I and the LLR III. The latter reflexes are rarely seen in normal subjects but have a significance in several diseases. Several abnormalities could be demonstrated in different diseases. Enhanced HR and reduced LLR are found in spasticity of various origin. Enhanced LLR I are frequently seen in Parkinson's disease, essential tremor and reflex myoclonus. Absent or reduced LLR II is found in Huntington's disease and in different focal brain lesions but not in symptomatic choreatic syndromes of other origin. Delayed latencies of the LLR II or absent LLR II have been described in multiple sclerosis. Enhanced LLR III may occur in cerebellar diseases. The method to elicit LLR of thenar muscles by electric stimulation may prove to be useful for clinical neurophysiology.
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PMID:Physiology and clinical applications of hand muscle reflexes. 228 56

An autopsy case of a 66 year-old woman is reported. She developed personality change and psychotic symptoms at the age of 58. She began to show gait disturbance and forgetfullness at the age of 60. She was admitted to Okayama University Hospital at the age of 61, when she showed personality change, dementia, cerebellar sings and chorea like involuntary movement. The illness progressed slowly and she died of septicemia at the age of 66. At autopsy brain weighed 990 g. Macroscopically, the atrophy of the brain stem was severe, and the cerebellum was slightly atrophic. Microscopically, the globus pallidus was almost intact, but the degeneration involved dentate nuclei, their projections, red nucleus and the subthalamic nuclei, so this case was considered to be a case of pseudo-Huntington form of dentatorubropallidoluysian atrophy, proposed by Hirayama. The most striking feature of this case was marked atrophy of the brain stem and her intense familial history. Investigation of her familial history revealed that there were 18 affected cases in 5 successive generations. Their onset of the disease varied from the age of 10 to 60 years old. Cases of juvenile onset showed myoclonus and convulsion as the initial symptoms, and convulsion as the initial symptoms, and those of presenile onset showed dementia, cerebellar ataxia and chorea like involuntary movement. And in some of these cases it was proved by NMR-CT that their brain stem were small. We discussed the meaning of the atrophy of the brain stem in these cases and the difference of the symptoms between the cases of juvenile onset and the cases of presenile onset.
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PMID:[An autopsy case of dentatorubropallidoluysian atrophy showing marked atrophy of the brain stem]. 296 93

Experiments are described in which the gamma-aminobutyric acid (GABA) antagonist bicuculline was injected into the lentiform complex of conscious monkeys. Injections into either the lateral segment of the globus pallidus, or the medial part of the putamen, gave rise to chorea of the contralateral limbs and/or orofacial region. Control injections of vehicle alone were without effect. Injections of bicuculline into the lateral part of the putamen gave rise to contralateral myoclonus. The chorea produced by lateral pallidal or medial putaminal injections was virtually indistinguishable from the dyskinesia (chorea/ballism) which has been shown, in previous studies, to be induced by injection of GABA antagonists into the subthalamic nucleus. It is proposed that the primary site of action of the GABA antagonist in producing chorea, in the present studies, was the lateral segment of the globus pallidus. The mode of action is suggested to be interruption of GABAergic transmission from the striatum to the lateral pallidal segment. Since this also occurs in Huntington's disease, it is proposed that experimental chorea induced by this method in the monkey may be a useful model of the dyskinesia seen in Huntington's disease in man. Loss of influence of inhibitory striatopallidal fibres would lead to abnormally increased activity of lateral pallidal neurons. These in turn project to the subthalamic nucleus, upon which they have an inhibitory action. Dyskinesia is thus produced by physiological inhibition of the subthalamic nucleus, whose destruction, both in man and the monkey, is known to produce ballism. It is proposed that ballism and chorea share common neural mechanisms, both involving the loss of influence of the subthalamic nucleus on the medial segment of the globus pallidus.
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PMID:Chorea and myoclonus in the monkey induced by gamma-aminobutyric acid antagonism in the lentiform complex. The site of drug action and a hypothesis for the neural mechanisms of chorea. 317 91

The ability of the selective GABA-receptor agonist, progabide, to suppress abnormal involuntary movements was evaluated in a preliminary open pilot study. 17 patients, 10 males and 7 females, aged 10-78 years, with hyperkinetic movement disorders were included in the study. Daily doses of progabide ranged from 900 to 3600 mg (median 2400 mg) corresponding to 14-45 mg/kg (median 45 mg/kg), while the duration of treatment varied from 2 to 52 weeks. Improvement, with a reduction of involuntary movements exceeding 25%, occurred in two of four patients with Gilles de la Tourette's syndrome, and in two of three patients with postanoxic intention myoclonus, while no consistent beneficial effects were registered in ten patients with Huntington's chorea, postanoxic choreoathetosis, torsion dystonia, tardive dyskinesia, action tremor, essential myoclonus, or oro-branchio-respiratory myoclonus.
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PMID:Progabide in the treatment of hyperkinetic extrapyramidal movement disorders. 386 33


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