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Biomedical subjects

A M Bonnet

Publications and source records attributed to A M Bonnet.

10 recordsLinked to original sources
PubMed1992

In-vivo SPECT imaging of D2 receptor with iodine-iodolisuride: results in supranuclear palsy.

We assessed the potential use of [123I]iodolisuride (ILIS), a new iodine ergolene derivative, to study human striatal D2 dopamine receptors with SPECT. In normal subjects, we found that the tracer accumulated preferentially in striatum. This was prevented by high doses of haloperidol. The striatal accumulation was maximal between 60 and 180 min after injection. The striatum-to-cerebellum radioactivity concentration ratio as an index of specific binding, measured 60 min after injection, was 1.52 +/- 0.19 (mean +/- s.d.) in controls and 1.36 +/- 0.11 in patients with supranuclear palsy (p less than 0.03). Our results show that ILIS may be used to study D2 receptors with SPECT. In-vivo changes of D2 receptors in human brain may be detected with this method.

Adult↗
PubMed1991

Tremor and idiopathic dystonia.

The clinical and electromyographic characteristics of tremor were studied in 45 patients presenting with various forms of idiopathic dystonia. Dystonic tremor was shown to be postural, localized, and irregular in amplitude and periodicity, absent during muscle relaxation, exacerbated by smooth muscle contraction, and associated frequently with myoclonus. Although it resembles essential tremor, dystonic tremor seems to be a distinct entity: it is more irregular with a broader range of frequencies; it is asymmetric and remains localized; myoclonus is sometimes associated. This type of tremor is most often seen in the presence of dystonia, but may be observed without evident dystonic symptoms.

Adolescent↗
PubMed1991

Does ageing aggravate parkinsonian disability?

The influence of age of onset of Parkinson's disease on the severity and the pattern of motor symptoms was investigated by comparing the motor scores with and without levodopa therapy in two groups of patients divided according to age of onset (early less than 50, late greater than 60 years) and matched for disease duration (n = 69 in each group, Study I). The baseline score, that is, the motor disability of patients when off levodopa, was similar in the early- and late- onset groups. In contrast, the residual motor score, assessed when the effect of levodopa treatment was maximum and stable, was significantly higher in the late onset group. When the two groups of patients were matched, in addition, for their residual motor score, (n = 54 in each group, Study II), no difference was observed between the early and late onset groups, except for gait disorder which was more severe in older patients. These results suggest that age of onset mainly affects the response to levodopa therapy, because it may increase the prevalence of non-dopaminergic lesions of the brain, including those responsible for gait disorders.

Age Factors↗
PubMed1979

Bromocriptine associated with a peripheral dopamine blocking agent in treatment of Parkinson's disease.

A peripheral dopaminergic blocking agent, domperidone (60 mg daily), or placebo was given, double-blind, to 17 parkinsonian patients who also received increasing doses of bromocriptine. Combined treatment with domperidone reduced total disability by 76% in 8 patients receiving a mean dose of 148 mg of bromocriptine daily. There was no vomiting and involuntary movements and psychic disturbances were similar to those in patients on levodopa and a peripheral decarboxylase inhibitor. In 9 patients taking placebo instead of domperidone, the average daily dose of bromocriptine could not be raised beyond 92 mg. The mean total disability score in this group was reduced by only 48%. Thus, peripheral blockade of dopamine receptors is a promising means of limiting the adverse side-effects of the treatment of parkinsonism with central dopaminergic receptor stimulating agents such as bromocriptine.

Adult↗
PubMedDate not supplied

[Abnormal movements caused by L-DOPA in patients with Parkinson's disease: correlation with the plasma concentrations of DOPA and O-methyl-DOPA].

This study involved twleve parkinsonian patients exposed to abnormal movements provoked by L-DOPA. Including six patients with "mid-dose" dyskinesias and six others with "onset and end of dose" dyskinesias, Correlation between the circumstances of onset of abnormal movements and plasma concentrations of DOPA and O-methyl-DOPA, after administration of a dose of L-DOPA + IDC, gave the following results: 1) mid-dose dyskinesias appeared with the highest plasma concentrations of DOPA, at the maximum therapeutic effect; 2) onset and end of dose occurred during rise and fall in plasma levels of DOPA, coinciding with the relief and the reappearance of parkinsonian symptoms respectively; 3) no correlation could be established between plasma concentrations of O-methyl-DOPA and the duration of the period of clinical remission or of abnormal movements. These biochemical data, completed by the neuropharmacological study of one patient with onset and end of dose abnormal movements suggest the predominant role of a disturbance in central dopaminergic mechanisms in the genesis of abnormal movements, whatever their nature.

Dihydroxyphenylalanine↗