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Biomedical subjects

L Vacca

Publications and source records attributed to L Vacca.

At least 37 records · Page 2Linked to original sources
PubMed1998

Botulinum toxin restores presynaptic inhibition of group Ia afferents in patients with essential tremor.

We studied the effect of botulinum toxin A injection on the abnormal presynaptic phase of reciprocal inhibition between forearm antagonist muscles in patients with essential tremor. Ten patients with essential tremor were investigated before and 1 month after botulinum injection. Reciprocal inhibition was studied by conditioning the H reflex in forearm flexors with a radial-nerve stimulus delivered at a range of time intervals. Botulinum toxin produced a significant functional improvement in tremor (about 20%). Before botulinum toxin injection, patients had a reduced presynaptic phase of reciprocal inhibition. After botulinum toxin this phase was significantly more pronounced. The normal early disynaptic phase of reciprocal inhibition was normal before and after botulinum treatment. Although botulinum treatment reduced the size of the H reflex and the M wave to a similar extent, it left the H/M ratio unchanged. These findings show that botulinum toxin treatment restores presynaptic inhibition between forearm antagonist muscles. The results are also consistent with botulinum toxin having a beneficial effect in patients with essential tremor. Both effects probably depend upon the toxin's concurrent action on the extrafusal and intrafusal motor end-plates, the latter resulting in decreased spindle afferent input to the spinal cord.

Adult↗
PubMed1998

Alterations of motor cortical inhibition in patients with dystonia.

Cortical inhibitory mechanisms were investigated with the technique of paired transcranial magnetic stimulation in 10 patients with dystonia of the right arm: six patients had focal, task-specific dystonia (writer's cramp) and three had segmental and one had generalized dystonia. Paired stimuli were delivered in a conditioning-test design during slight voluntary activation of the target muscle, with subthreshold conditioning stimuli at short intervals (3-20 ms) and suprathreshold conditioning stimuli at long intervals (100-250 ms). The amount of inhibition at short interstimulus intervals did not differ significantly between patients and normal subjects. With long interstimulus intervals, patients showed more inhibition of the test response, which was significant at the 150-ms interval. The cortical silent period following a single suprathreshold magnetic stimulus was slightly shorter in patients. No significant difference was detected between the affected side and the unaffected side in patients with unilateral task-specific dystonia, neither in the duration of the silent period nor in the response to paired magnetic stimuli. These results indicate that the different types of motor cortical inhibition are produced by different inhibitory circuits. We propose that the alterations observed in patients with dystonia are the result of impaired feedback from the basal ganglia to motor cortical areas, with the ultimate effect of a flattening of the excitability curve of the cortical motoneuron pool during voluntary muscle activation.

Adult↗
PubMed1997

Guidelines for the therapeutic use of botulinum toxin in movement disorders. Italian Study Group for Movement Disorders, Italian Society of Neurology.

Since its introduction in the early '80s the use of botulinum toxin has improved the quality of life of the patients affected by movement disorders. Toxin's neuromuscular blocking action allows a symptomatic treatment of those clinical conditions characterised by excessive muscular activity. Although the dosages used are safe and the side-effects are reversible, a correct use of botulinum toxin depends on the knowledge of its clinical pharmacology and of the anatomy of the body segments to be injected. In addition, the treatment of more complex conditions, i.e. laringeal dystonia, imposes an inter-disciplinary approach and specialised injection techniques. In this review, the Italian Study Group on Movement Disorders presents the consensus guidelines for the therapeutic use of botulinum toxin in movement disorders. The main toxin types, their use and administration modalities, and the training guidelines will be presented.

Botulinum Toxins↗
PubMed1997

Low dose of clozapine in the treatment of dopaminergic psychosis in Parkinson's disease.

Dopaminergic psychosis frequently complicates the pharmacological treatment of Parkinson's disease. Dose reduction of dopaminomimetic therapy or treatment with conventional neuroleptics improves psychosis but worsens parkinsonism. In an open-label 12-month trial, the clinical antipsychotic efficacy of the atypical neuroleptic clozapine was investigated in 36 parkinsonian patients (age range 46-85 years) with symptoms of dopaminergic psychosis including delusions, vivid dreams, hallucinations, frank paranoid delirium, and hypersexuality. Clozapine, given orally at bedtime, was started at a dose of 6.25 mg and titrated upward to the minimal effective dose. In all patients, psychosis responded to very low clozapine doses (mean 10.59 +/- 6.48 mg/day). Clozapine doses correlated with the severity of psychosis. During clozapine treatment, parkinsonian disabilities and levodopa dosage remained statistically unchanged. During the 12-month study, no patient had clozapine-induced agranulocytosis or other severe side effects. These findings indicate that even at low doses, clozapine effectively controls dopaminergic psychosis in Parkinson's disease patients without compromising motor function.

Aged↗
PubMed1997

The long-duration action of levodopa may be due to a postsynaptic effect.

A single dose of levodopa (L-DOPA) reduces motor disability in Parkinson's disease (PD) for a few hours, a short-duration effect. However, there are suggestions that L-DOPA may also produce a long-duration benefit of some days. In the present study, we examined the long-duration action of L-DOPA by observing the time taken to achieve maximum stable benefit after starting a constant dose of sinemet-CR (sinemet-CR) (200 g L-DOPA/50 mg carbidopa) twice daily in nine newly diagnosed patients, and the time taken to deteriorate back to baseline after stopping treatment. A single dose of sinemet-CR (200 mg L-DOPA/50 mg carbidopa) had little obvious short-duration action on the Unified PD Rating Scale (UPDRS) motor scores in the majority of patients, either before starting chronic sinemet-CR therapy (200 mg L-DOPA/50 mg carbidopa, b.i.d.) or after chronic treatment. However, all patients gradually improved on chronic sinemet-CR therapy, taking 9.3 +/- 1.8 days to achieve maximum response. On stopping chronic sinemet-CR treatment, it took 6.8 +/- 3.0 days for the same patients to deteriorate back to baseline motor disability. In similar experiments, the time taken to deteriorate back to baseline after stopping treatment with the directly acting dopamine agonist ropinirole (9-21 mg daily) in eight other de novo patients with PD was found to be 6.2 +/- 1.7 days. The long-duration effect of L-DOPA and ropinirole may, therefore, be due to some slowly evolving postsynaptic pharmacodynamic change in the central nervous system (CNS). Loss of this long-duration action may be responsible for the emergence of motor fluctuations on chronic L-DOPA therapy.

Adult↗
PubMed1996

Fluctuating parkinsonism: a pilot study of single afternoon dose of levodopa methyl ester.

Thirty-four patients with idiopathic fluctuating Parkinson's disease and early afternoon "delayed on" or severely resistant "off" periods, in spite of long-term antiparkinsonian therapy, were studied. The first afternoon levodopa administration was substituted with an equimolar dosage of the liquid formulation levodopa methyl ester (LDME). The major end-points for efficacy were latency to "on" and duration of "on" periods. The patients were divided into five subgroups according to their baseline treatment and they were evaluated monthly for 6 months using the Unified Parkinson's Disease Rating Scale. The patients completed weekly self-evaluation using an "on-off" chart. LDME was well tolerated by all the patients. A statistically significant reduction in latency to "on" was observed in all patients. The clinical effect of LDME remained stable during the treatment period (repeat measures ANOVA). The more rapid clinical effect of LDME and its stable and predictable antiparkinsonian activity represents a new and useful approach for treating patients with complicated Parkinson's disease.

Administration, Oral↗
PubMed1996

Motor fluctuations in levodopa treatment: clinical pharmacology.

Fluctuations in motor performance and dyskinesias are a common problem in the long-term management of Parkinson's disease. The pharmacokinetics and the pharmacodynamics of levodopa, loss of presynaptic dopamine terminals, alterations in postsynaptic dopamine receptor sensitivity, or changes in the modulatory influences of nondopaminergic transmitter system could play a pathogenic role. The short half-life of levodopa and its absorption and transport are important factors. The pharmacodynamic response to levodopa changes during long-term therapy. An absolute threshold in plasma levodopa level, below which the patients are off, appears. The patients show a therapeutic window for levodopa which becomes narrower with time. This therapeutic window can be widened by giving continuous infusion of dopaminergic drugs. Motor fluctuations can be ameliorated by a more physiological continuous stimulation of the receptor site and by avoiding repeated shifting in levodopa levels. Long-term complications are attenuated by an early combination of levodopa with dopamine agonist.

Antiparkinson Agents↗
PubMed1995

Differential diagnosis of parkinsonism.

The diagnosis of idiopathic Parkinson's disease (PD) is essentially clinical and is reached by exclusion. An akinetic rigid syndrome frequently means PD, although a number of other neurodegenerative diseases can share bradykinesia, rigidity, postural instability, and sometimes tremor. Parkinsonism can be classified as follows: degenerative, metabolic, vascular, iatrogenic, toxic, infectious, traumatic, and secondary to mass effect. The diagnostic approach are discussed.

Atrophy↗
PubMed1985

Application of the Psychiatric Reform Act in the city of Naples. A survey of requests for compulsory admission to the special unit at the University Psychiatric Department I.

One of the most patent inconsistencies in the application of the 1978 Psychiatric Reform Act in many areas of Southern Italy has resulted from the irrational choice, by regional governments, of the general hospitals in which Psychiatric Special Units had to be implemented, and from the inappropriate determination of territorial boundaries defining the competence of such Units. Thus, in the city of Naples, it was decided, in June 1978, to set up Psychiatric Special Units only in the two University Psychiatric Departments and in the Psychiatric Emergency Ward at S. Gennaro Hospital. These Units, equipped with an overall number of 39 beds, were put in charge with the whole province of Naples (about three millions inhabitants). Quite arbitrarily, it was established that University Departments had to admit patients coming from the city of Naples and S. Gennaro Hospital those residing in the rest of the province. By an equally arbitrary choice, female patients from the city of Naples were entrusted to the University Department I and male patients to the Psychiatric Department II. In the following years, from 1979 to 1983, some additional Units were set up in general hospitals of the Naples province. Nonetheless, available beds have not exceeded the overall number of 69, and the catchment areas of the three pre-existing Special Units have not been modified. The chaotic situation engendered by this incongruous application of the Reform Act is outlined, by means of an analysis of the requests for compulsory admission addressed to the Special Unit at the Psychiatric Department I of Naples University during the periods June 16, 1978-December 31, 1979 and June 16, 1982-December 31, 1983.

Commitment of Persons with Psychiatric Disorders↗
PubMed1981

Transcultural aspects of depressive symptomatology.

The following is a presentation of the first results of a cross-cultural study of depressive symptomatology, within the framework of a larger research project which is still in progress. Southern Italian and northern Swedish depressed patients completed a self-rating scale for depression and were rated by the doctors using a subscale of the Comprehensive Psychological Rating Scale. In the doctors' ratings Italian patients scored higher for variables referring to motor retardation and hypochondriasis, and Swedish patients for variables referring to inability to feel and agitation. These findings were in line with expectations. In contrast, in the self-ratings Swedish patients scored higher for the variables weight loss, tachycardia and agitation and Italian patients for hopelessness and loss of interest and dissatisfaction. This discrepancy between results in self-ratings and doctors' ratings might reflect cultural differences either in the way patients in the two countries are able to express verbally their symptoms or in the way doctors from the two countries give weight to different symptoms. Taking the results of the two ratings together as a general measure of the severity of the depressive disorder, patients in the two places appeared to be quite alike. Since the two centers are engaged in comprehensive investigations of depressed patients, the last-mentioned finding suggests that the populations in the two centers are comparable as concerns severity.

Adult↗
PubMed1980

Computerized EEG in schizophrenics.

20 psychiatric patients without pharmacologic therapy and an homogeneous control group of 19 healthy subjects have been submitted to an electroencephalographic (EEG) investigation. Computerized spectral analyses of the main EEG frequency bands have been performed. The spectra have been determined by some geometrical descriptors: the relative activity, the barycentric frequency and the barycentric radius; also classic descriptors have been used as complementary ones. In the EEG profile significant differences between patients and healthy subjects have been found. Some differences have also been observed among subgroups of schizophrenic patients. The geometrical descriptors applied in the EEG analysis are suggested as a useful method in the description of the basic characteristics of the main EEG frequency bands.

Adult↗
PubMed1978

The comprehensive psychopathological rating scale (CPRS): communicability to, and inter-rater reliability among untrained raters.

Twenty-six, respectively twenty-three untrained Italian doctors participated in the rating of two patients with a preliminary Italian version of the CPRS. Despite an unfavourable setting, and some linguistic inaccuracies in the translation, a quite satisfactory degree of agreement was reached among the doctors. The Italian version of the CPRS has now been rewritten using a terminology more familiar to Italian psychiatrists.

Humans↗
PubMed1977

Effect of maternal vitamin A excess on S-100 in neonatal rat cerebellum: a preliminary study.

Pregnant rats were administered a teratogenic dose of vitamin A excess on Days 17 and 18 of gestation and intubation controls received the vehicle alone. Pups were sacrificed at birth or on postnatal Days 5 or 10; the cerebellum was removed, frozen, and fixed in preparation for immunohistochemical localization of the brain specific protein, S-100. Vitamin A produced a transient delay in the appearance of S-100 in the external granular layer which was no longer evident on Days 5 and 10. These findings corroborate autoradiographic evidence that vitamin A temporarily interferes with neurogenesis. However, the early damage results in permanent behavioral deficits in adulthood despite apparent cytochemical repair.

Animals↗