S Bernardini

Intravenous amantadine improves levadopa-induced dyskinesias: an acute double-blind placebo-controlled study.

Experimental evidence suggests that glutamatergic receptor blockade may improve the motor response complications associated with long‐term levodopa treatment in Parkinsons disease (PD) patients. Our objective was to evaluate the acute effect of amantadine, a noncompetitive antagonist of the N‐methyl‐D‐aspartate (NMDA) receptor, on levodopa‐induced dyskinesias, and to gain further insights into the antidyskinetic mechanism of this drug. Nine PD patients with motor fluctuations and severely disabling peak of dose dyskinesias received their first morning levodopa dose, followed by a 2‐hour intravenous amantadine (200 mg) or placebo infusion, on two different days. Parkinsonian symptoms and dyskinesias were assessed every 15 minutes during the infusion and for 3 hours thereafter, while patients were taking their usual oral antiparkinsonian therapy, by means of Unified Parkinsons Disease Rating Scale (UPDRS, motor examination), tapping test, and a modified Abnormal Involuntary Movement Scale (AIMS). Intravenous amantadine acutely improved levodopa‐induced dyskinesias by 50%without any loss of the anti‐parkinsonian benefit from levodopa. This study confirms the antidyskinetic effect of amantadine and strengthens the rationale for using antiglutamatergic drugs in the treatment of parkinsonian motor fluctuations.

Oxidative damage and cytogenetic analysis in leukocytes of Parkinson’s disease patients

Background: Postmortem studies suggest excessive free radical toxicity in the substantia nigra of patients with PD. Increased lipid peroxidation and oxidative DNA damage have been reported in the CNS. Markers of oxidative stress have been identified in the blood of patients with PD. Objective: To assess the presence of spontaneous chromosome and primary or oxidative DNA damage in peripheral blood leukocytes of patients with untreated PD. Methods: Patients with de novo PD (20) and control subjects (16), matched for age, sex, and smoking habits, underwent cytogenetic analysis using the human lymphocyte micronucleus assay coupled with the fluorescence in situ hybridization technique and the Comet assay. Results: Compared with controls, patients with PD showed an increase in the incidence of spontaneous micronuclei (p < 0.001); single strand breaks (p < 0.001); and oxidized purine bases (p < 0.05). Fluorescence in situ hybridization analysis showed micronuclei harboring acentric fragments. Conclusions: There is chromosomal, primary DNA damage and oxidative DNA damage demonstrable in lymphocytes of patients with untreated PD.

Cytogenetic alterations in lymphocytes of Alzheimer's disease and Parkinson's disease patients

Abstract. We investigated the presence of cytogenetic alterations in peripheral blood lymphocytes of Alzheimers disease (AD) and Parkinsons disease (PD) patients. Detection of spontaneous structural and/or numerical chromosome damage has been assessed by micronucleus (MN) assay coupled with fluorescence in situ hybridization (FISH). The cytogenetic investigation was performed on 22 AD patients, 18 PD patients, and 20 controls. The spontaneous frequencies of micronuclei (MN) in human lymphocytes of both AD and PD patients were significantly higher than in controls. The majority of MN was composed of whole chromosomes in AD patients, while a prevalence of MN arising from chromosome breakage was observed in PD patients. Different molecular mechanisms underlie cytogenetic alterations observed in peripheral lymphocytes of AD and PD patients.

Proton magnetic resonance spectroscopy (1H-MRS) of motor cortex and basal ganglia in de novo Parkinson's disease patients

Abstract Proton MR spectroscopy (1H-MRS) has been previously performed in Parkinsons disease (PD) and parkinsonian syndromes to evaluate in vivo concentrations of basal ganglia and cerebral cortex metabolites such as N-acetylaspartate (NAA), choline (Cho), and creatine (Cr). However, this technique has never been used to evaluate motor cortex in untreated PD patients. In this study, single-voxel 1-H-MRS of basal ganglia and motor cortex was carried out in 10 de novo patients with PD and 10 age-matched healthy controls. A significant reduction in the NAA/Cr ratio was observed in the motor cortex of PD patients compared with controls (p<0.01). Basal ganglia spectra did not allow any evaluation due to the presence of artefacts related to inorganic paramagnetic substances. The motor cortex reduction of the NAA/Cr ratio in de novo PD patients may reflect an altered neuronal functioning due to a loss of thalamocortical excitatory inputs and may represent an in vivo marker for the diagnosis of PD.

Cytogenetic analysis oxidative damage in lymphocytes of Parkinson's disease patients

Abstract Several lines of evidence support the presence of DNA damage in somatic cells of Parkinsons disease (PD) patients due to the formation of free radical species. In order to detect spontaneous chromosome and primary or oxidative DNA damage, we performed the human lymphocyte micronucleus assay (HLMDA) and comet assay in 19 PD patients and 16 healthy controls. Compared with controls, PD patients showed a significant increase in: (1) spontaneous micronucleus (MN) frequency (p<0.001); (2) single strand break (SSB) levels (p<0.001); and (3) oxidized purine base levels (p<0.05). The chromosome damage and the increased levels of oxidized purine bases observed in our patients support the hypothesis of oxidative stress as a relevant factor in the pathogenesis of PD.

Diurnal motor variations to repeated doses of levodopa in Parkinson's disease

Patients with Parkinsons disease (PD) in long-term levodopa therapy often complain of worsening of motor symptoms in the afternoon and evening. The pathophysiology of this phenomenon is not known. We evaluated the motor response to repeated doses of levodopa during a 12-hour period in 52 parkinsonian patients (19 de novo, 20 stable, and 13 wearing-off). On the day of the study, all patients received standard doses of levodopa/carbidopa at 8:00 a.m., 12:00 noon, and 4:00 p.m. Motor measurements such as tapping test, walking time, and tremor score, and blood samples for levodopa and 3-O-methyldopa (3OMD) plasma analysis, were performed hourly. Mean motor scores and pharmacokinetic data, evaluated for a period of 3 hours after each levodopa dose, were compared. In de novo patients, we did not observe diurnal changes in motor score, whereas a progressive daytime worsening was visible in stable and wearing-off patients. No significant difference in levodopa pharmacokinetics after each levodopa dose was observed within each patient group, whereas 3OMD plasma levels significantly increased with repeated levodopa administrations. However, no significant correlation between motor scores and 3OMD plasma levels was observed, suggesting that the diminishing motor response to afternoon and evening doses of levodopa in patients in long-term levodopa therapy does not relate to the pharmacokinetics of the drug. It is possible that this phenomenon may be an expression of the occurrence of tolerance to repeated doses of levodopa.

Amantadine in Huntington’s disease: open-label video-blinded study.

Abstract. Huntingtons disease (HD) is characterized by chorea, cognitive and behavioral changes. Amantadine, a non-competitive NMDA receptor antagonist, has shown an antidyskinetic effect on levodopa-induced dyskinesias, which are known to have strict pathogenetic analogies with choreic hyperkinesias. The antidyskinetic efficacy of amantadine and its effects on cognitive and behavioural symptoms were evaluated. Eight HD patients received oral amantadine (100 mg tid) unblinded for a 1-year period. A significant reduction of dyskinesias was reported (p<0.01). No changes were observed in neuropsychologic and psychiatric assessments after 6 and 12 months of therapy. These data may have relevance to the treatment of HD with amantadine.

Mexiletine in the treatment of torticollis and generalized dystonia.

Mexiletine is an antiarrhythmic drug that has been reported to exert antidystonic properties. We performed an open-label study to collect further evidence of the antidystonic effect of mexiletine in spasmodic torticollis (ST) and to evaluate its possible use in generalized dystonia. We administered mexiletine to six patients with dystonia (three with generalized dystonia and three with ST) who had failed to respond to previous pharmacotherapy. The drug was started at a dose of 200 mg/d by mouth and increased up to a maximum dose of 800 mg/d. Patients were evaluated at regular intervals over a 6-week period with use of the Fahn & Marsden Dystonia Scale and the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and videotaped. At the end of the trial, the videotapes were reviewed and scored by a blind observer. Patients were then followed for at least 1 year and evaluated every 3 months at the dose reached during the study period. No adverse effects were reported in five patients; in one patient, dizziness developed at the dosage of 800 mg/d, requiring a reduction of the dose. At the end of a 6-week period, a significant improvement in the rating scale for dystonia and in videotape ratings was observed after mexiletine treatment (p < 0.01). Our data indicate that mexiletine is a useful drug in dystonia treatment.

Brain perfusion effects of cholinesterase inhibitors in Parkinson’s disease with dementia

Summary.Several evidences suggest that cholinergic deficits may significantly contribute to dementia in Parkinson’s disease (PDD) and acetylcholinesterase inhibitors (ChEIs) have been reported to improve cognitive symptoms in PDD, without worsening parkinsonism. Nineteen PDD patients underwent brain perfusion SPECT with 99mTc-ethyl cysteinate dimer after 6 months ChEIs treatment in order to evaluate the functional correlates of clinical improvement. A clear-cut cognitive improvement was reported in PDD patients with a significant improvement of ADAS-cog total score as well as of subscores exploring executive functions (p < 0.01). MMSE total score did not significantly change after ChEIs but the subscore of attention significantly improved after therapy (p < 0.01). No difference in motor performance as evaluated by UPDRS was reported. SPM analysis showed a significant increase of perfusion (p < 0.0001) in bilateral cingulate, and frontal regions after ChEIs. Our data confirm the efficacy of ChEIs in the treatment of dementia associated with PD mainly on attention and executive functions, and the functional findings indicate that this cognitive improvement could be associated with a sort of pharmacological frontal “re-afferentation”.

Treatment of patients with tardive dystonia with olanzapine

Tardive dystonia represents a complication of long-term use of neuroleptics and its treatment is often unsatisfactory. Atypical neuroleptics appear to improve tardive dystonia, and cases of tardive dystonia successfully managed with clozapine have been reported. The aim of this open-label video-blinded study was to evaluate the antidystonic efficacy of olanzapine, a new atypical neuroleptic with a low risk of agranulocytosis, in a group of four patients (one man and three women) with tardive cervical dystonia. They developed severe dystonia after several years of neuroleptic treatment. Extensive laboratory evaluations, as well as neurophysiologic and neuroradiologic investigations, were negative. Olanzapine was started at a dose of 5 mg/d and increased up to 7.5 mg/d. All patients were evaluated at baseline and after 2, 4, 8, and 12 weeks of treatment, using the Toronto Western Spasmodic Torticollis Rating Scale, and videotaped. At the end of the trial, the videotapes were reviewed and scored by a blind observer. A self-rating visual analog scale completed the disability evaluation.A moderate to marked improvement in dystonia was observed in all patients, and significant differences were observed in Toronto Western Spasmodic Torticollis Rating Scale scores and videotape ratings after 8 and 12 weeks of treatment compared with the basal values (p < 0.05). The average percentage of improvement in Toronto Western Spasmodic Torticollis Rating Scale score and visual analog scale was 26.4% and 42.6%, respectively. No serious side effects were reported at the maximum dosage reached (7.5 mg/d). This study warrants a larger controlled study to conclusively demonstrate the efficacy of olanzapine in tardive dystonia.