1/9. The coincidence of schizophrenia and Parkinsonism: some neurochemical implications.The hypothesis has recently been advanced that increased activity of central dopaminergic mechanisms underlies the symptomatology of the schizophrenias. The evidence that dopaminergic transmission in the corpus striatum is impaired in Parkinson's disease suggests that observations on the relationship between Parkinson's disease and schizophrenia may illuminate the patholophysiology of the latter disease. Four cases are reported in which an illness with schizophrenic features developed in the setting of longstanding Parkinson's disease; attention is drawn to earlier reports of schizophrenic illnesses occurring as postencephalitic sequelae in the presence of a parkinsonian syndrome. These observations appear to conflict with the view that increased dopamine release in the striatum is necessary for the expression of schizophrenic psychopathology, but do not exclude the possibility that increased transmission may occur at other dopaminergic sites in the brain, for example the nucleus accumbens, tuberculum olfactorium or cerebral cortex. Similarly the dopamine receptor blockade hypothesis of the therapeutic effects of neuroleptic drugs cannot be maintained with respect to an action in the striatum in view of the differences between the actions of thioridazine and chlorpromazine in this structure, but may be tenable for actions at extra-straital sites.- - - - - - - - - - ranking = 1keywords = nucleus (Clic here for more details about this article) |
2/9. Ineffective subthalamic nucleus stimulation in levodopa-resistant postischemic parkinsonism.The authors report a patient with postischemic parkinsonism who responded neither to levodopa nor to bilateral subthalamic nucleus (STN) stimulation. MRI revealed bilateral lesions of the substantia nigra, the striatum, the external pallidum, and part of the internal pallidum. PET showed reduced striatal dopa-decarboxylase activity, D2 receptor binding, and glucose metabolism. Perioperative microrecording showed low-frequency activity of STN cells. This case suggests that parkinsonian patients who do not have a good response to levodopa or in whom a postsynaptic dopaminergic lesion can be shown may not be good candidates for STN surgery.- - - - - - - - - - ranking = 210.81462242533keywords = subthalamic, nucleus (Clic here for more details about this article) |
3/9. Vascular Parkinsonism: a case report and review of the literature.Vascular Parkinsonism (VP) is characterised by sudden onset and rapid progression of clinical symptoms, absent or poor response to dopamine substitution therapy, and postural instability with shuffling gait and absence of tremor, making it a clinically distinct entity from idiopathic Parkinson's disease (IPD). Furthermore, it displays certain typical findings in neurological investigations. We report on a patient presenting features of VP associated with an intracerebral lesion not ascribed to VP to date, namely an isolated ischaemic focal lesion located in the left cerebral peduncle between the substantia nigra and nucleus ruber as evidenced by magnetic resonance imaging (MRI). The pathophysiological organic correlate for contralateral extrapyramidal symptoms in this patient may be an interruption of nigro-thalamic projection, interrupting the final subcortical station in the cortic-striato-pallido-nigro-thalamico-cortical loop central to the pathophysiology of parkinsonian syndromes. Non-response t o levodopa therapy could be a consequence of disruption of the cortico-basal ganglia-cortical loop on account of ischaemic destruction of subcortico-cortical axons, the underlying pathology, therefore, not being the result of a loss of nigral dopaminergic neurons or striatal dopamine deficiency pathogonomonic of IPD. To our knowledge, this is the first case of clinically manifest VP to be described with a single lesion in the contralateral cerebral peduncle between the substantia nigra and nucleus ruber, and suggests alternative intracerebral patterns for the distribution of disease-causing lesions in VP, and possibly new pathophysiological explanations for the nature of this disease.- - - - - - - - - - ranking = 2keywords = nucleus (Clic here for more details about this article) |
4/9. Contralateral disappearance of parkinsonian signs after subthalamic hematoma.A man with Parkinson's disease (PD) suddenly developed a left hemiballismus, and the CT showed a hematoma of the right subthalamic nucleus. After the ballistic movements had disappeared, akinesia and the other parkinsonian signs did not reappear on the left. This clinical case confirms the involvement of the subthalamic nucleus in the akinesia of PD, as suggested by recent experimental data.- - - - - - - - - - ranking = 248.97754691039keywords = subthalamic, nucleus (Clic here for more details about this article) |
5/9. Further observations showing the impact of the probenecid test in movement disorders.Two patients with movement disorders are described and neurochemically studied. The first subject concerns a central anticholinergic syndrome in a 83 years old man treated with l-dopa and amantadine for red nucleus tremor. The second one is an association of parkinsonism and chorea in a 76 years old woman presenting with FAHR's syndrome. In both cases, CSF HVA levels were measured before and after oral probenecid load. The observations confirm the usefulness of this neurochemical strategy in order to classify aging patients with parkinsonism into dopasensitive and doparesistant groups.- - - - - - - - - - ranking = 1keywords = nucleus (Clic here for more details about this article) |
6/9. Serial MRI in infantile bilateral striatal necrosis.A 3-year-old girl with left hemiparesis suffered from bilateral paresis, motor rigidity, gait disturbance, axial hypotonia, dysarthria, apathy, and incontinence. After steroid therapy, mild improvement occurred, but muscle weakness, gait disturbance, and rigidity remained. Leigh encephalopathy was excluded on the basis of muscle biopsy and laboratory findings. Computed tomography and serial magnetic resonance imaging at an early stage revealed right-sided dominant lesions in the putamen and caudate nucleus and later bilateral striatal lesions, appearing as hyperintense signals on T2-weighted images and mixtures of hypo- and hyperintense signals on T1-weighted images. This is the first demonstration of serial magnetic resonance imaging findings in infantile bilateral striatal necrosis.- - - - - - - - - - ranking = 1keywords = nucleus (Clic here for more details about this article) |
7/9. Hemiparkinsonism-hemiatrophy syndrome: neuroradiological and neurophysiological findings.A rare form of secondary parkinsonism has been recently described as 'hemiparkinsonism-hemiatrophy syndrome'. We report a case with such clinical features. A neurophysiological study of the evoked potentials, somatosensory and motor, has been conducted. We stress the neuroradiological findings at nuclear magnetic resonance, which documented the presence of an area of altered signal in the mesencephalon, between the cerebral pedunculus and the red nucleus on the right side. The etiopathogenetic considerations and diagnostic criteria are discussed. Moreover we evaluate the efficacy of levodopa therapy.- - - - - - - - - - ranking = 1keywords = nucleus (Clic here for more details about this article) |
8/9. reflex blepharospasm associated with bilateral basal ganglia lesion.A patient with a bilateral striatal lesion secondary to anoxia presented reflex blepharospasm associated with parkinsonism and dystonia in the limbs. The blink reflex excitability curve was enhanced and the R-2 response prolonged as in patients with essential blepharospasm. The findings in this patient support the notion that blepharospasm may be secondary to basal ganglia dysfunction through abnormal facilitation of reticular formation neurons controlling facial nucleus motoneuron excitability.- - - - - - - - - - ranking = 1keywords = nucleus (Clic here for more details about this article) |
9/9. Clinical and pathological features in hydrocarbon-induced parkinsonism.A neuropathological examination was performed on a patient with parkinsonism induced by prolonged exposure to a mixture of aliphatic hydrocarbons, mainly n-hexane and halogenated compounds. The patient developed a rapid-course disease that progressed even after withdrawal from the toxic exposure. Pathological examination and immunohistochemical analysis of the brain revealed severe and widespread dopaminergic neuronal loss, associated with severe gliosis, in the substantia nigra, and almost complete loss of tyrosine hydroxylase immunostaining in the striatum. No lewy bodies were detected. Neuronal loss was also observed in the periaqueductal gray matter, locus ceruleus, and pedunculopontine nucleus. These changes, combined with the moderate anemia due to marrow suppression, and the mild axonal neuropathy observed in vivo, are suggestive of a hydrocarbon toxic insult.- - - - - - - - - - ranking = 1keywords = nucleus (Clic here for more details about this article) |