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PubMed1996

Wilson disease: findings at MR imaging and CT of the brain with clinical correlation.

PURPOSE: To describe the spectrum of brain abnormalities in Wilson disease (hepatolenticular degeneration) as depicted at magnetic resonance (MR) imaging and computed tomography (CT) and to relate these findings to neurologic and hepatologic abnormalities. MATERIALS AND METHODS: Fifty patients with Wilson disease participated in the cross-sectional study: Patients underwent cerebral MR imaging (n = 49), CT (n = 44), abdominal duplex ultrasound (US) (n = 46), and neurologic examination (n = 50) within a week. Relative risk and the Fisher exact test were used for statistical analysis. RESULTS: Supratentorial and infratentorial abnormalities in the gray and white matter were found in the pyramidal and extrapyramidal system. In Wilson disease, an abnormal striatum depicted on MR images correlated with pseudoparkinsonian signs, an abnormal dentatothalamic tract correlated with cerebellar signs, and an abnormal pontocerebellar tract correlated with pseudoparkinsonian signs. The presence of portosystemic shunt was strongly associated with abnormality of the globus pallidus. CONCLUSION: MR imaging findings were of some use in the clinical treatment of patients with Wilson disease.

Adult↗
PubMed2001

[Anatomy and basic knowledge of the spinal cord].

Basic knowledge of macroscopic anatomy is needed to understand the clinical signs and distinct syndromes resulting from the disturbed function of the tracks, segments and roots of the spinal cord. The cord is contained within the vertebral canal, continuing the medulla down to the conus medullaris. Descending tracks are motor (corticospinal and extrapyramidal), and ascending tracks are sensory (spinothalamic and lemniscal). Spinal cord involvement must be considered when a sensorimotor spinal tract and a radicular spinal syndromes are combined. Syringomyelia, Brown-Séquard syndrome and subacute combined degeneration of the spinal cord must also be familiar to clinicians, as well as how to differentiate a conus medullaris from a cauda equina syndrome.

Humans↗
PubMed1996

Immunocytochemical localization of serotonin1A receptors in the rat central nervous system.

Specific anti-rat 5-hydroxytryptamine1A (serotonin1A) receptor antibodies raised in a rabbit injected with a synthetic peptide corresponding to a highly selective portion of the third intracellular loop of the receptor protein (El Mestikawy et al. [1990] Neurosci. Lett. 118:189-192) were used for immunohistochemical mapping of serotonin1A receptors in the brain and spinal cord of adult rats. The highest density of immunostaining was found in limbic areas (lateral septum, CA1 area of Ammon's horn and dentate gyrus in the hippocampus, and frontal and entorhinal cortices), in the anterior raphe nuclei, and in the interpeduncular nucleus, in agreement with previous autoradiographic studies with selective radioligands showing the enrichment of these regions in serotonin1A receptor binding sites. Serotonin1A receptor-like immunoreactivity was also present, but at a moderate level, in the neocortex, in some thalamic and hypothalamic nuclei, in the nucleus of the solitary tract, in the dorsal tegmentum, in the nucleus of the spinal tract of the trigeminal nerve, and in the superficial layers of the dorsal horn in the spinal cord. In contrast, extrapyramidal areas, including the caudate putamen, the globus pallidus, and the substantia nigra as well as the cerebellum, exhibited very low to no immunostaining by antiserotonin1A receptor antibodies. At the cellular level, both the plasma membrane of neuronal perikarya and fine neuronal processes probably corresponding to dendritic fields were found to bind antiserotonin1A receptor antibodies. Regional differences were noted regarding these two types of immunostaining, because only dendrites bound antibodies within the hippocampus and the lateral septum, whereas both dendrites and neuronal cell bodies were immunoreactive in the medial septum, in the diagonal band of Broca, and in the dorsal and median raphe nuclei. Therefore, differential addressing of serotonin1A receptors could occur from one neuron to another. In general, the distribution and density of serotonin1A receptor-like immunoreactivity in the whole brain and in spinal cord were consistent with the mapping of serotonin1A receptor binding sites and serotonin1A receptor mRNA previously established by immunoautoradiographic and in situ hybridization procedures.

Animals↗
PubMed1992

Magnetoelectrical stimulation of motor cortex in children with motor disturbances.

Transcranial magnetoelectrical stimulation (TMS) is now widely used as a diagnostic tool in adults. In this study we report our experiences with this technique in children with central motor disturbances. We used a Cadwell MES10 magnetoelectrical stimulator with a maximal magnetic field of 2 tesla. The stimulation procedure followed a standardized protocol, with the patients being as relaxed as possible in order to avoid contamination of parameters with different preinnervational levels. Stimulation data were compared to a data base obtained in 58 normal children. The first group of patients consisted of 20 children aged from 7 months to 16 years with hemiparesis of different etiologies. Neuroimaging data were correlated with the results of magnetoelectrical stimulation. In 13 patients a pathological pattern of TMS could be detected, and in 7 of these a corresponding lesion of the cortico-spinal tract was found in CT or MRI scans. In 7 children TMS was normal, in spite of a clear-cut lesion of the cortico-spinal tract in CT or MRI scans in 4 of them. The second group of patients consisted of 16 children with extrapyramidal disease, mostly of hereditary origin, such as DOPA-responsive dystonia or benign hereditary chorea. TMS showed a normal response pattern in this group. We discuss problems and possible pitfalls in TMS in childhood in evaluating the diagnostic value of TMS. At the moment the diagnostic usefulness of TMS in children with motor disturbances appears limited and calls for careful interpretation.

Adolescent↗
PubMed2000

Extrapyramidal side effects, tardive dyskinesia, and the concept of atypicality.

The most frequent problems associated with the older generation of antipsychotic agents are extrapyramidal side effects (EPS) and tardive dyskinesia. Neuroleptic-induced EPS are thought to be caused by blockade of nigrostriatal dopamine tracts resulting in a relative increase in cholinergic activity; tardive dyskinesia is less well understood but is thought to be a supersensitivity response to chronic dopamine blockade. The leading hypothesis for the mechanism of action of the newer generation of atypical antipsychotics is the presence of a high serotonin-to-dopamine receptor blockade ratio in the brain. When serotonergic activity is blocked-as is the case with atypical antipsychotics-dopamine release increases and balances out the dopamine blockade effect at postsynaptic receptor sites, which results in few or no EPS. Prospective data indicate that the risk of tardive dyskinesia in patients taking atypical antipsychotics is less than that for those taking typical antipsychotics. This article reviews the mechanisms of neuroleptic-induced EPS and tardive dyskinesia and discusses the relationship between these movement disorders and atypical antipsychotic agents.

Antipsychotic Agents↗
PubMed1990

Selective dopamine D2 antagonist and prolactin response in acute schizophrenia--results from remoxipride studies. The Canadian Remoxipride Study Group.

1. In a double-blind dose finding study prolactin was assessed at baseline and end of treatment in three groups of acute schizophrenics receiving low, intermediate and high doses of remoxipride as compared to a controlled group that received haloperidol. 2. Remoxipride only in high doses (300-600 mg daily) has produced a modest increase in prolactin levels at endpoint as compared to the much higher increase in prolactin secretion that accompanied haloperidol treatment. 3. The weak effects on prolactin as well as the previously reported low incidence of extrapyramidal side effects confirm the profile of remoxipride as a selective dopamine D2 antagonist with preferential effects on the mesolimbic and mesocortical tracts. 4. Male responders to either remoxipride or haloperidol treatment had significantly higher baseline prolactin levels regardless of dose and drug used. In females, there was no difference in baseline prolactin between responders and nonresponders.

Adult↗
PubMedDate not supplied

Cholinergic neuropil of the striatum observes striosomal boundaries.

Acetylcholine and dopamine are key neurotransmitters in the extrapyramidal motor system, where they are thought to lie in a 'functional balance' brought about by interactions between the terminals of the dopamine-containing nigrostriatal tract and the cholinergic interneurones of the striatum. The precise nature of these interactions is not understood, however, nor is it clear how they influence the functioning of striatal systems containing other neurotransmitters. A new clue to understanding such interplay among transmitter-coded systems in the striatum has come from the finding that many of them, including nigrostriatal afferents, follow a macroscopic ordering in which neural elements are concentrated either in or out of the striatal tissue compartments called striosomes. We here report that the cholinergic neuropil of the striatum is also compartmentalized: fibres expressing immunoreactivity to antibodies raised against choline acetyltransferase (ChAT) are sparse in striosomes and are dense in the extrastriosomal matrix. These findings suggest that the interactions between acetylcholine and other neurotransmitters in the striatum are spatially constrained, that cholinergic modulation of striatal function predomintes in the extrastriosomal matrix, and that extrapyramidal pathways originating in the matrix, including transthalamic pathways to the frontal lobes, may in particular reflect this cholinergic influence. Such a differential organization of striatal cholinergic circuitry could help to account for the selective therapeutic efficacy of anticholinergic drugs in the treatment of extrapyramidal disorders.

Acetylcholinesterase↗
PubMed1986

[Long loop reflexes--a clinically relevant method].

Late reflex potentials have been know for a long time. On the upper limb it has been proven that these potentials have a transcortical pathway. The electrical stimulation of nerve trunks is easily applicable in clinical practice and produces clear long-loop responses. The typical results can be reproduced for extrapyramidal, cerebellar and pyramidal lesions by this method. The long-loop reflex is sensitive to lesions in the course of the pyramidal tract.

Adult↗
PubMed1991

Three-dimensional trajectory analysis of congenital mirror movements in a single subject.

Mirror movements are involuntary movements executed by one side of the body that occur with voluntary activation of homologous muscles of the other side. Although such movements have been described qualitatively and with surface EMG recordings, the spatial and temporal characteristics of these movements remain relatively unexplored. We studied selected simple and complex upper limb movements in a 20-yr.-old woman with congenital mirror movements and no other neurological disorder. Movements were digitized in three-dimensional space, reconstructed computergraphically, and analyzed numerically and graphically. Mirror movements had smaller amplitudes than did the corresponding voluntary movements, and there was, in general, temporal coupling between mirror and voluntary movements. Nonetheless, mirror movements were not always a perfect mirror image of the corresponding voluntary movements and sometimes differed in timing and trajectory shape from the original movement. Substantially larger mirror movements were elicited by distal than by proximal movements, and mirror movements were enhanced when loads were applied to the hand executing the voluntary movement. These data support the proposal that congenital mirror movements are produced by a partial failure of decussation of the pyramidal tract. We suggest that the variability in the extent to which mirror movements correspond to the voluntary movements is due to propriospinal and descending extrapyramidal input.

Adult↗
PubMed1992

A dose-finding study with remoxipride in the acute treatment of schizophrenic patients.

Two hundred and forty-two patients with acute schizophrenia were enrolled in a double-blind, comparative, dose-finding study of a novel antipsychotic, remoxipride. Remoxipride was evaluated in a low (30 to 90 mg), medium (120 to 240 mg) and a high (300 to 600 mg) dose range and compared with a haloperidol (15 to 45 mg), which was administered to a similar group of patients. The results support the antipsychotic effect of remoxipride, with maximum efficacy occurring at daily doses between 120 mg and 600 mg. Side-effects were more frequent at doses of remoxipride over 300 mg. In all groups, remoxipride caused consistently fewer extrapyramidal side-effects than haloperidol. The antipsychotic effect of remoxipride may be derived from specific blockade of dopamine D2 receptors in the mesolimbic tract. The findings also suggest that remoxipride may have a therapeutic effect on negative symptoms of schizophrenia.

Dose-Response Relationship, Drug↗
PubMedDate not supplied

[18q syndrome with deficiency of myelin basic protein (MBP)].

The Authors present a patient with 18q- Syndrome in which lymphatic cell karyotype could resume development of extrapyramidal degeneration signs before they appeared. Severity range of phenotypic manifestations in the 18q- syndrome is correlated with chromosomic breakpoint and with genetic background. Many chromosome 18's distal arm genes have been mapped Myelin Basic Protein gene (MBP) has been located in 22-23 position; it forms about 30-40% of myelinic sheath proteins. Failure in MBP gene expression would be correlated in the central white matter with extrapyramidal system degeneration signs: in 18q- patients with involuntary movements studied by MRI or by post-mortem autopsy unmyelinated areas in central white matter tracts have been put in evidence. As MBP absence in peripheral nervous system does not appear to have a functional effect, it has been suggested that some specific component of peripheral myelin is functionally equivalent to MBP and capable to substitute this protein in its absence.

Age Factors↗
PubMed1980

Specific and non-specific multiple unit activities during pentylenetetrazol seizures. I. Animals with 'encéphale isolé'.

The present report describes the sequence of activation and deactivation of multiple unit activities (MUA) in the brain stem reticular formation and pyramidal tract, in relation to the clinical seizure and electroencephalographic and electromyographic tonic-clonic discharges induced by pentylenetetrazol (PTZ), in cats immobilized by high spinal transection ('encéphale isolé'). Threshold doses of PTZ (20 mg/kg i.v.) produced the following events: (1) Significant increase in mesencephalic and pontine MUA, anticipating 2 (+/- 1) sec the clinical and electromyographic seizures and 5 (+/- 2) sec the onset of EEG and pyramidal tract tonic-clonic discharges. (2) A further increase in mesencephalic and pontine reticular MUA and electromyogram MUA at the onset of EEG and pyramidal tract tonic-clonic discharges. (3) Significant decrease of EEG spike activity and pyramidal tract MUA to levels below the control period 16 (+/- 8) sec later, while mesencephalic and pontine MUA and electromyogram remained very high. Results suggest that (i) PTZ-induced seizures start in the brain stem reticular formation and propagate to muscles by at least two different pathways: a pyramidal and an extrapyramidal pathway; (ii) that inhibition of seizure activity may start at the cortical level.

Action Potentials↗
PubMed1996

[A case of atypical progressive supranuclear palsy with degeneration of the fronto-pontine tracts, and without grumose degeneration of the dentate nucleus].

An autopsy case of progressive supranuclear palsy (PSP) with degeneration of the fronto-pontine tracts of the midbrain and pons, and without grumose degeneration of the dentate nucleus is reported. A 72-year-old woman was suffering from dysarthria and gait disturbance. Moderate dementia was noted and gradually worsened. Pyramidal and extrapyramidal signs and cerebellar ataxia were not observed. Eye movements were fully preserved. Brain CT showed cerebellar atrophy. Three years later, she was unable to stand or move, and became mutistic. At the age of 75, she died suddenly. The duration of her illness was approximately 4 years. Clinical diagnosis was LCCA (late cortical cerebellar atrophy). Neuropathological examination revealed gliosis of the deep layers of the cerebral cortex around the precentral gyrus, fronto-pontine tracts degeneration (posterior part of the anterior crus, genu and anterior part of the posterior crus of the internal capsule, cerebral peduncles of the midbrain, pontine base and pyramis of the medulla oblongata). Also, atrophy of the pons and marked degeneration of the superior colliculi and substantia nigra were observed. Neurofibrillary tangles (NFTs) and glial fibrillary tangles (GFTs) were found in the subcortical nuclei. These findings were almost consistent with PSP. However, the following differed from those of previously reported typical PSP cases: firstly, mild gliosis in the reticular formation of the midbrain; secondly, few NFTs in the pontine nuclei and superior colliculi and; thirdly, no grumose degeneration in the dentate nucleus. In addition, clinical symptoms of the present case are not consistent with PSP. Therefore, we concluded this case to be an atypical PSP both clinically and neuropathologically.

Aged↗
PubMed1988

Intraoperative monitoring of the motor function: experimental and clinical study.

Manipulation of the lesions adjacent to the primary motor area or the motor pathway is troublesome for neurosurgeons because they lack an effective method to determine the primary motor area or to monitor motor function in the operative room. It will be of great value to establish a monitoring method of the corticospinal tract under general anaesthesia. We recorded the motor evoked potential (MEP) from direct motor cortex stimulation in cats and showed that it derives almost purely from the corticospinal tract. Then we used this technique during the operation of the resection of tumours near the primary motor area or the motor pathway. 1. Experimental study: Twenty adult cats were used in this study. Recording electrodes were flexible bipolar catheter electrodes inserted into the spinal epidural space. Stimulating electrodes were silver ball electrode on the cortex (anode) and needle electrode in the temporal muscle (cathode). Stimulation of 4-24 V, 5-10 Hz and 0.2 msec in duration were done and evoked potentials signals were averaged 60 to 512 times. MEP with multiple peaks was obtained that had a 112 msec conduction velocity in the spinal cord. We found the same signals from the stimulation of ipsilateral cerebral peduncle. Radiofrequency lesioning of ipsilateral cerebral peduncle produced a loss of MEP. These results show that MEP derives from the corticospinal tract. Significant wave form change, with components of short latency, was noted by the excessively intense stimuli. We supposed that superimposition of the signals from the extrapyramidal pathways, excited in the brain stem, results in this change.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗