Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0030567 (Parkinson's disease)
 63,064 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Clinical Neurophysiology brings about 2 major contributions in the study of Parkinson's disease: on the one hand, it makes it possible to measure the motor troubles; on the other, it enables their pathophysiological analysis. The 3 classical signs must be studied separately. Tremor can easily be recorded by electromyography. Moreover, its parkinsonian nature can be specified by studying the resetting of EMG bursts following electrical stimulation of the motor nerve. A pace maker has been demonstrated in the thalamus from where rhythmic messages are first sent to motor cortex and thereafter reverberated to spinal motoneurons. Rigidity can be assessed by sophisticated but not generalized methods. It is easier to evaluate it by long-loop responses evoked by proprioceptive or exteroceptive stimulations. These responses reflect activity in pathways relaying in supraspinal structures. Contrary to spasticity, rigidity is not basically due to dysfunctions in segmentary spinal circuits. It is more likely that it depends on hyperactive and hyperexcitable long loop pathways. This hypothesis is in agreement with well established facts showing that parkinsonian hypertonia vanishes after dorsal root section. Akinesia is complex semeiologically. It is made of various components some of which can be measured. Reaction times and movement times provide interesting data which however are not strictly correlated with the motor handicap. Motor programmes are assembled in normal delays but they are not "called upon" correctly, reflecting a disturbance in the motor planning. A lack of "energetization" of the motor cortex and the pyramidal tract is likely. A functional disconnection between the motor program/plan side and the execution side can be hypothesized to explain the 3 major signs; on the one hand, neural messages are not correctly transferred to the pyramidal system, on the other, spinoencephalospinal loops on the execution side become more active as they escape from the control normally exerted by the plan/program side where basal ganglia play a prominent role.
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PMID:[Clinical neurophysiology in the evaluation and physiopathology of Parkinson's disease]. 383 95

The static and dynamic components of the tonic stretch reflex and shortening reactions have been studied in 10 patients with athetosis. EMG activity could be recorded only from the biceps muscle when the patient was at rest. The dynamic stretch reflex increased with the velocity of stretching in all muscles examined except the biceps. The biceps stretch reflex was found to be inhibited by increasing muscle length, whereas the stretch reflexes of triceps, hamstrings, and quadriceps muscles were facilitated by increasing muscle length. Reinforcement increased resting activity in the biceps and the dynamic shortening reaction of the triceps muscle. Both these effects were suppressed by the action of phenoxybenzamine. Although phenoxybenzamine was shown to reduce muscle tone in a double-blind controlled trial, no corresponding improvement was detected in involuntary movements or the patients' performance in a tracking test. The differences between the pattern of hypertonus in athetosis, Parkinson's disease, spasticity, and activated normal subjects are presented in discussion.
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PMID:Electromyographic study of the rigidospasticity of athetosis. 457 Sep 5

Most disorders of motor activity including disturbances of muscle tone and of locomotor activity observed in patients with neurological disorders have been reproduced experimentally in animals. Most motor disorders of the extrapyramidal type including those associated with Parkinson's disease and choreiform and athetoid involuntary movements, have been reproduced exclusively in primates. This is most likely related to the highly complex organization of the extrapyramidal and related nervous mechanisms subserving the corresponding peculiar type of motor control in the primate brain. Other types of motor disturbances including cervical and trunkal dystonias, ataxia, hypotonicity, spasticity and intention tremor, however, have been successfully induced in various mammalian species. The latter types of motor disorders are related to disturbances of central nervous mechanisms which show similar patterns in the brains of different animal species. Histopathological and neurochemical changes associated with extrapyramidal disorders have been discovered and more precisely determined as a consequence of the development of new technical approaches. Therefore numerous morphological, physiological and neurochemical data concerning the extrapyramidal system are now available but a better knowledge of their precise and subtle interrelationship is greatly needed in order to develop more efficient therapeutic procedures.
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PMID:Behaviour correlates of neurotransmitter activity. 614 9

Torque curves were recorded during passive and active ankle joint movements at three preset angular velocities (30, 60 and 120 degrees/s) with the subject in the supine position and 45 degrees hip and knee angles. Recordings were performed in normal subjects (n = 11), patients with clinical spasticity (n = 10) and patients with Parkinson's disease (n = 7). The torque curves recorded during passive dorsiflexion followed by plantar flexion showed a counterclockwise hysteresis loop with minimal area in the normal subjects and a large area in patients, especially at the highest velocity. The torque increase during dorsiflexion was proportional to the angular velocity in the patients with spasticity but not in the patients with Parkinson's disease. In the patients with spasticity, a good correlation was found between clinical assessment of hypertonia and measurements of torque during passive movements but not torque values during maximal voluntary dorsiflexion. A model for data reduction and estimation of instant slope values on different parts of the torque-angle curve is suggested. The use of ankle torque recordings for evaluation of treatment effects is exemplified.
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PMID:Measurement of torque during passive and active ankle movements in patients with muscle hypertonia. A methodological study. 658 32

Sixty-five cases of clinically diagnosed multiple lacunar state have been analysed. The clinical course of multiple lacunar state is usually progressive in nature, simulating degenerative diseases, in contrast with the mode of acute onset seen in the other vascular diseases. Average age at the initial visit was 63.8 year-old, and sex ratio showed marked male preponderance, being 12 for males and 1 for females. Gait disturbance and speech disturbance are the most frequent initial symptoms, followed by slow motion, emotional lability and swallowing difficulty. Neurological manifestations are dysarthria, short-stepped and apraxic gait, hyperreflexia, positive Babinski and Chaddock reflexes, minimal spasticity, dementia, positive palmo-mental reflex, emotional lability, fixed face, rigidity, bradykinesia, foot grasping, dysphagia, positive Myerson's sign and tremor, in the order described. The important point is that the rigidity is paratonic and the tremor is action or postural, not the cogwheel rigidity or resting tremor like Parkinson's disease. The appearance of pathological reflexes (Babinski and Chaddock reflexes) are quite important, especially Chaddock reflex, which can frequently become positive despite negative or equivocal Babinski reflex. Hypertension, especially longstanding in nature, is the major contributing factor in this disorder. CT scan showed the presence of one or more lacunes in 52 out of 65 cases (80.0%). The detection of lacune can be influenced by the quality of CT scan, and the high resolution CT scanner is greatly useful for that purpose. It is stressed that the detailed neurological and computed tomographic evaluations will make it possible to reach the clinical diagnosis and appropriate treatment of multiple lacunar state.
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PMID:[Clinical studies on multiple lacunar state]. 674 15

The author's interest in the motor system is traced over a period of 30 years. Early studies on the cat pyramidal tract proved to be of relevance to later work on the control of muscle tone by brain stem and cortical mechanisms. Application of physiological methods disclosed fundamental differences between the increased tone of Parkinson's disease, spasticity and decerebrate rigidity. These differences depend upon the extent to which dynamic and static stretch reflexes are released, and whether the control effects of flexor reflex afferents remain under the control of the brain stem (as in Parkinson's disease), are released (as in spasticity) or even reversed (as in decerebrate rigidity).
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PMID:Disordered muscle tone and movement. 692 89

Memantine is an uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist with therapeutic potential in dementia, spasticity and Parkinson's disease. The Ki-value of memantine at the phencyclidine (PCP) binding site of the NMDA receptor is 0.5 microM in human frontal cortex. We investigated whether concentrations of memantine in cerebrospinal fluid (CSF) and serum samples under therapeutic conditions are in the range of its Ki-value at the PCP binding site. The serum levels ranged from 0.025 to 0.529 microM with daily doses between 5 and 30 mg. CSF levels were highly correlated to serum levels and were below serum levels in each patient with a mean CSF/serum ratio of 0.52. Serum and CSF levels were correlated to the daily dose, but not to the duration of treatment. At the concentrations reported here, memantine is expected to specifically interact with the PCP binding site of the NMDA receptor.
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PMID:Cerebrospinal fluid and serum concentrations of the N-methyl-D-aspartate (NMDA) receptor antagonist memantine in man. 747 69

An in vitro mammalian model neuronal system to evaluate the intrinsic toxicity of soman and other neurotoxicants as well as the efficacy of potential countermeasures was investigated. The link between soman toxicity, glutamate hyperactivity and neuronal death in the central nervous system was investigated in primary dissociated cell cultures from rat hippocampus and cerebral neocortex. Exposure of cortical or hippocampal neurons to glutamate for 30 min produced neuronal death in almost 80% of the cells examined at 24 h. Hippocampal neurons exposed to soman for 15-120 min at 0.1 microM concentration caused almost complete inhibition (> or = 90%) of acetylcholinesterase but failed to show any evidence of effects on cell viability, indicating a lack of direct cytotoxicity by this agent. Acetylcholine (ACh, 0.1 mM), alone or in combination with soman, did not potentiate glutamate toxicity in hippocampal neurons. Memantine, a drug used for the therapy of Parkinson's disease, spasticity and other brain disorders, significantly protected hippocampal and cortical neurons in culture against glutamate and N-methyl-D-aspartate (NMDA) excitotoxicity. In rats a single dose of memantine (18 mg/kg) administered 1 h prior to a s.c. injection of a 0.9 LD50 dose of soman reduced the severity of convulsions and increased survival. Survival, however, was accompanied by neuronal loss in the frontal cortex, piriform cortex and hippocampus.
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PMID:Assessment of primary neuronal culture as a model for soman-induced neurotoxicity and effectiveness of memantine as a neuroprotective drug. 749 76

We studied the effects of botulinum toxin A in 12 patients with spasticity and in eight patients with rigidity. The study design was a double-blind, placebo-controlled crossover trial with botulinum toxin A versus saline. Using the Ashworth Scale for spasticity and the Unified Parkinson's Disease Rating Scale for rigidity, we gave the patients a tone grade before and 2 weeks after treatment. Improvement in tone by two grades or more was considered clinically significant. In the spasticity group, botulinum toxin A reduced the tone of all patients significantly, improved functionality and nursing care in eight of 12 patients, and alleviated painful spasms in five of five patients. In the rigidity group, muscle tone was decreased in seven of eight patients, functionality improved in four of seven, and joint and muscle pain decreased in four of five. We conclude that botulinum toxin A is effective against the disabling effects of spasticity and rigidity. The treatment was well tolerated.
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PMID:Botulinum toxin A for spasticity, muscle spasms, and rigidity. 772 60

Memantine, an amantadine derivative, is therapeutically used for the treatment of various neurological and psychiatric disorders such as Parkinson's disease, spasticity, and dementia. Pharmacokinetics of memantine and its effects on phospholipid content and composition, on membrane properties and functions such as fluidity and beta-adrenergic transmission were studied in cultured human fibroblasts and macrophages. The kinetic behaviour of memantine was characteristic for a lysosomotropic drug. Fibroblasts exposed to 14C-memantine in the microM range accumulated the drug up to 200 fold above initial medium concentrations. Lysosomal drug storage was proven by indirect evidence and by analyses of subcellular fractions. Repetitive exposure to memantine resulted in a cumulative uptake. While memantine uptake after single exposure was fully reversible, the rate and extent of release of chronically accumulated drug was reduced but could be enhanced by the addition of unlabelled memantine or ammonium chloride to the medium. Chronic, but not single, exposure to memantine above 10 microM resulted in a concentration dependent phospholipid accumulation and in a shift in the phospholipid composition. There was an overproportionate increase in phosphatidylinositol at the expense of phosphatidylserine and sphingomyelin. Chronic exposure of cultured cells to memantine increased fluidity in the superficial layers of the plasma membrane and reduced the isoproterenol-stimulated cAMP-response without affecting beta-adrenoceptor density. All these findings were compatible with the kinetic behaviour and the effectiveness expected of a weak lysosomotropic drug.
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PMID:Evidence for lysosomotropism of memantine in cultured human cells: cellular kinetics and effects of memantine on phospholipid content and composition, membrane fluidity and beta-adrenergic transmission. 829 47


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