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)

Dementia of the Alzheimer-type (DAT) is characterized by progressive cognitive decline, variably combined with frontal lobe release signs, parkinsonian symptoms and myoclonus. The features of diffuse Lewy body disease (DLBD), the second most common cause of degenerative dementia, include progressive cognitive deterioration, often associated with levodopa-responsive parkinsonism, fluctuations of cognitive and motor functions, psychotic symptoms (visual and auditory hallucinations, depression), hypersensitivity to neuroleptics and orthostatic hypotension. A recent report suggests that positron emission tomography studies in patients with degenerative dementia may be useful in the differential diagnosis of DAT and DLBD. However, the diagnostic role of single-photon emission tomography (SPET) studies remains to be established. The aim of this study was therefore to evaluate regional cerebral perfusion [with either technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) or 99mTc-ethyl cysteinate dimer (99mTc-ECD) SPET] and striatal dopamine transporter density [using iodine-123 2 beta-carboxymethoxy-3 beta-[4-iodophenyl]tropane (123I-beta-CIT) SPET] in patients with DAT and DLBD. Six patients with probable DAT and seven patients with probable DLBD were studied. Blinded qualitative assessment by four independent raters of 99mTc-HMPAO or 99mTc-ECD SPET studies revealed bilateral temporal and/or parietal hypoperfusion in all DAT patients. There was additional frontal hypoperfusion in two patients and occipital hypoperfusion in one patient. In the DLBD group, regional cerebral perfusion had a different pattern. In addition to temporoparietal hypoperfusion there was occipital hypoperfusion resembling a horseshoe defect in six of seven patients. In the DAT group, the mean 3-h striatal/cerebellar ratio of 123I-beta-CIT binding was 2.5 +/- 0.4, with an increase to 5.5 +/- 1.1 18 h after tracer injection. In comparison, in the DLBD patients the mean 3-h striatal/cerebellar ratio of 123I-beta-CIT binding was significantly reduced to 1.7 +/- 0.3, with a modest increase to 2.1 +/- 0.4 18 h after tracer injection (P < 0.05, Scheffe test, ANOVA). These results suggest that 99mTc-HMPAO or 99mTc-ECD and 123I-beta-CIT SPET may contribute to the differential diagnosis between DAT and DLBD, showing different perfusion patterns and more severe impairment of dopamine transporter function in DLBD than in DAT.
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PMID:Brain perfusion scintigraphy with 99mTc-HMPAO or 99mTc-ECD and 123I-beta-CIT single-photon emission tomography in dementia of the Alzheimer-type and diffuse Lewy body disease. 914 72

To determine the role of the metabolites of L-arginine in its actions on picrotoxin-induced convulsions in rats, the concentrations of nitric oxide (NO) and L-citrulline were measured in the brain 30 and 60 min after the administration of L-arginine (1000 and 2000 mg/kg) or of N-nitro-L-arginine methyl ester (L-NAME, 30 mg/kg), an inhibitor of NO synthase. Animals treated similarly were challenged 30 and 60 min later with picrotoxin (5mg/kg), and the time of onset of myoclonus and clonic convulsions and the frequency of convulsions were determined. These parameters were also determined 30 and 60 min after administering L-arginine in L-NAME-pretreated (30 min) animals. Thirty minutes after the administration of L-arginine, the concentrations of both NO and L-citrulline were raised, the onset of myoclonus and clonic convulsions was delayed, and the frequency of convulsions was decreased, indicating the anticonvulsant property of L-arginine. A 60-min treatment of L-arginine produced a further increase in the concentration of L-citrulline but not that of NO and promoted the frequency of picrotoxin-induced convulsions. Pretreatment with L-NAME prevented L-arginine from raising the concentrations of both NO and L-citrulline; it also promoted the anticonvulsant actions and prevented the proconvulsant actions of L-arginine. These results lead to the conclusion that NO has no involvement in the time-dependent anti and proconvulsant actions of L-arginine on the picrotoxin convulsion model, and that L-citrulline seems to have a role in the proconvulsant action of L-arginine.
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PMID:Evidence for the involvement of L-citrulline but not nitric oxide in the proconvulsant action of the precursor L-arginine on picrotoxin-induced convulsions in rats. 1209 79

A 78-year-old female patient with a 5-year history of bradykinesia and tremor at rest of both upper limbs was referred to our Nuclear Medicine Department because of a rapid functional decline over 3 months with cognitive impairment, generalized myoclonus, and dependence for most basic daily activities. Brain SPECT with 148MBq (4 mCi) of I-123 FP-CIT and 740MBq (20 mCi) of Tc-99m ethylcysteinate dimer (thereafter Tc-99m ECD) was performed.
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PMID:Unexpected I-123 FP-CIT uptake in a brain tumor. 1969 25

Orthostatic tremor (OT) is not an uncommon symptom in various neurodegenerative diseases. However, the nature and pathophysiology of OT involve a complex network of tremors and dopaminergic pathways. We assessed patients who complained of prominent leg tremors described as "shaky leg." We analyzed their characteristics and evaluated them with neuroimaging and electrophysiological tools. A total of 23 patients who experienced an uncomfortable symptom of leg tremor were retrospectively enrolled from April 2014 to October 2019. Previous medical history, brain MRI, and surface electromyography (EMG) data were analyzed. The [18F]-FP-CIT brain positron emission tomography (PET) and the Unified Parkinson's Disease Rating Scale (UPDRS) were assessed for patients who showed parkinsonism. The causes of OT varied: parkinsonism (n = 5), idiopathic causes (n = 4), secondary causes (n = 3, trauma, brain lesion, arteriovenous malformation), drug reactions (n = 3, valproate, perphenazine, haloperidol), other neurological disorders (n = 5, essential tremor, dystonia, restless leg syndrome, REM sleep behavior disorder, dementia), alcohol withdrawal (n = 1), functional movement disorder (n = 1), and an unknown cause (n = 1). The frequency range varied (2.6-15 Hz) and according to the new consensus statement on the classification of OT, 4 patients had primary OT, 2 had "primary OT plus," 12 had slow OT, and 5 had orthostatic myoclonus. The prognosis associated with the use of medication was generally poor; however, clonazepam and levodopa were the most effective drugs. In conclusion, we found that different types of OT and orthostatic myoclonus were diagnosed by electrophysiological evaluation and neuroimaging tools even if they showed the same symptoms as "shaky leg." In addition, it is possible to roughly estimate the response to medication according to the type of OT and the cause. To clarify the pathophysiology of OT, a large number of longitudinal cohort studies and detailed neuroimaging and electrophysiological evaluations are needed.
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PMID:What Shall We Do for the Patients with Shaky Leg Syndrome? A Review of 23 Patients. 3291 73