Parkinson's disease: neurodegenerative mechanisms and neuroprotective interventions--report of a workshop.
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Biomedical subjects
Publications and source records attributed to S Fahn.
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A leading hypothesis of the pathogenesis of neuronal degeneration of the substantia nigra dopamine-containing cells in Parkinson's disease (PD) is excessive oxidative stress. In part, this oxidative stress is the result of the oxidation of dopamine by the action of monoamine oxidases (MAO) A and B to generate hydrogen peroxide and subsequent oxygen free radicals. Because of this hypothesis we have treated patients with early PD, not yet requiring any symptomatic treatment, with tranylcypromine, a drug that inhibits both MAO's. These patients were required to observe a tyramine-restricted diet. Thirty-seven patients on tranylcypromine have been followed by us for up to 33 months. Four patients discontinued the drug because of pending surgery. Of the remaining 33, six had adverse effects that lead to discontinuation of the drug, mainly impotency in men. Another common adverse effect encountered was insomnia, but this problem was not a cause of stopping the drug. Depression lifted in all five patients who had this problem at the time tranylcypromine was initiated. Only two patients have so far required treatment with levodopa or a dopamine agonist, and this need occurred within the first 6 months of treatment. The evaluation of all 37 patients revealed that parkinsonian symptoms improved slightly on introduction of tranylcypromine as measured by the United Parkinson's Disease Rating Scale, the Hoehn & Yahr Staging Scale, and the Schwab & England Activities of Daily Living Scale. Follow-up evaluations for a minimum of 6 months between the first post-tranylcypromine visit and the most recent visit revealed only slight worsening of parkinsonian signs and symptoms, with a mean interval of almost 1.5 years. A longer period of follow-up is needed to determine how long the severity of PD will remain mild in this group of patients.
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Idiopathic cervical dystonia (ICD) is the most common form of adult-onset focal dystonia. Previously, disagreement existed about whether ICD was a psychiatric illness, but the disorder is now viewed as a neurological illness and large clinical series have clarified the clinical features of the disease. At the time of diagnosis, extracervical dystonia is found in approximately 20% of patients, and there may be a concomitant head or hand tremor. Importantly, adult-onset ICD does not become generalized, although there may be segmental spread and pain may increase independently of the dystonia. While 10-20% of patients may experience remission, nearly all patients relapse within 5 years and are left with persistent disease. The aetiology of ICD is unknown, but there has been much progress in clarifying the genetic abnormality in families with inherited adult-onset cervical dystonia; linkage to chromosome 18p has been demonstrated in one family, and the DYT1 locus has been excluded in two other families. Painful trauma may be involved in the pathogenesis of ICD. Painful stimuli are received and processed by the basal ganglia, and the synaptic changes provoked by pain may lead to the abnormal physiology underlying dystonia. Consistent with this idea are experiments which demonstrate that altered sensory input leads to plasticity of the motor cortex, and those that explore the 'tonic vibration reflex' in patients with dystonia. Another theory suggests that a primary vestibular abnormality is responsible for ICD. Botulinum toxin is the most effective treatment for ICD. Roughly 75% of patients improve, and a response is generally seen within the first week. However, many questions remain regarding the optimal technique of administration. The development of neutralizing antibodies occurs in at least 5-10% of patients, and appears to be related both to dosage and to the interval between treatments. Side-effects are generally mild and result from the action of the toxin in the periphery. If the response to botulinum toxin is not adequate, anticholinergics, benzodiazepines, baclofen and other medications are used as adjunctive therapy. Surgical therapies are available for the treatment of ICD but are reserved for patients refractory to conservative measures.
Since the first successful attempts in 1990, human embryonic tissue transplantation has attracted the attention of multiple investigators and clinicians as a serious candidate therapy for Parkinson's disease. Although over two hundred patients have undergone the procedure, multiple issues and questions remain unresolved. We will address this topic emphasizing the recent advances in the technical aspects of the transplantation procedure in light of the limited animal and clinical experience available.
OBJECTIVE: To investigate the long term outcome of selective ramisectomy denervation in patients with botulinum toxin resistant spasmodic torticollis. BACKGROUND: The published surgical series of ramisectomy treatment for torticollis do not provide systematic information on patients who develop resistance to the current standard of treatment-botulium toxin injections. Moreover, there is little information on surgical outcome using rating scale measurements of torticollis, or assessments of functional and occupational capacity. METHODS: Using a structured interview format and videotape assessments of severity of dystonia in a retrospective fashion, detailed follow up information was obtained on 16 patients who underwent open label selective denervation for severe, disabling torticollis, refractory to injections of botulinum toxin. RESULTS: Of 16 patients with disabling torticollis followed up postoperatively for a mean of 5 years, six (37.5%) had a moderate or complete return of normal neck function, as determined using functional capacity scales, whereas 10 had only minimal relief of dystonia or gain in function. Six of the 16 patients (37.5%) underwent a second peripheral denervation operation, and one required a third. Of 11 patients working outside the home before surgery, nine were disabled by dystonia, and only one continued to work after surgery. Dystonia rating scale scores of videotaped examinations using a modification of the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) improved in 12 of 14 patients (85.7%) who underwent selective ramisectomy. When patients with primary botulinum toxin resistance were excluded, the magnitude of benefit for this subgroup was 31.9% of the baseline dystonia score (p<0.0002), comparable with the degree of improvement in a group of control patients receiving botulinum toxin treatment for torticollis. CONCLUSION: About one third of patients with torticollis resistant to injections of botulinum toxin may derive modest long term functional improvement from selective denervation, with a reduction in dystonia by about 30%, but remain unable to work.
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Alpha-Tocopherol concentrations were determined in the CSF of patients with early untreated Parkinson's disease receiving 2,000 IU vitamin E orally per day. After treatment the concentrations increased significantly (p < 0.001) by 76+/-10 (SE)%. The net increases in CSF alpha-tocopherol concentrations after treatment showed a significant positive correlation with the number of days of vitamin E ingestion (p < 0.001). Thus, high-dose vitamin E treatment results in elevating CSF vitamin E levels and possibly brain vitamin E levels.
OBJECTIVE: To evaluate the nonergot dopamine agonist ropinirole as an adjunct to L-dopa in a randomized, double-blind trial in PD patients with motor fluctuations. BACKGROUND: L-dopa in the treatment of PD is associated with motor fluctuations, dyskinesia, and other adverse effects. The use of dopamine agonists in the treatment of PD delays recourse to L-dopa and thus delays the possibility of adverse effect onset. METHODS: Ropinirole (n = 95) or placebo (n = 54) was added to L-dopa, and L-dopa was then reduced in a planned manner during the 6-month trial. RESULTS: A significantly greater number of ropinirole patients were able to achieve a 20% or greater reduction in both L-dopa dose and in percent time spent "off" compared with placebo (35.0% versus 13.0%; p = 0.003). The mean daily L-dopa dose was reduced significantly with ropinirole treatment (242 mg versus 51 mg; p < 0.001) as was the percent awake time spent "off" (11.7% versus 5.1%; p = 0.039). There was no difference in the percent of patients who withdrew because of adverse effects (15.8% on ropinirole versus 16.7% on placebo). CONCLUSIONS: Ropinirole permits a reduction in L-dopa dose with enhanced clinical benefit for PD patients with motor fluctuations.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
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Whipple's disease of the central nervous system (CNS) may be associated with normal intestinal histology as a result of minimal or patchy involvement. The diagnosis is difficult and is frequently made post mortem. We studied 6 patients with clinically suspected CNS Whipple's disease; 2 had oculomasticatury myorhythmia (OMM) fitting criteria for a diagnosis of definite CNS Whipple's disease. One of the 2 had duodenal histology highly suggestive of Whipple's disease the other 5 patients had normal duodenal histology. DNA was extracted from paraffin-embedded duodenal tissues in all patients and frozen pontine tissue in 1. Two primer pairs (W3F-W4R, W3F-W2R) were used in separate polymerase chain reactions (PCRs) to amplify fragments of Tropberyma whippelii 16S rDNA from these tissue samples. PCR amplicons were detected only in the duodenal tissues from the 2 patients with OMM. The sequences of these amplicons were identical to the corresponding region of the previously published Tropheryma whippelii 16S rDNA sequence. PCR-based assays of intestinal or brain tissue may be of value for confirming, and possibly refuting, a clinical diagnosis of CNS Whipple's disease in a patient with any combination of dementia, supranuclear gaze palsy, hypothalamic manifestations, myoclonus, seizures, ataxia, or OMM, especially when tissue histology is unrevealing.