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Biomedical subjects

M Vidailhet

Publications and source records attributed to M Vidailhet.

At least 55 records · Page 3Linked to original sources
PubMed2001

A major locus for several phenotypes of myoclonus--dystonia on chromosome 7q.

Myoclonus--dystonia is a genetically heterogeneous autosomal dominant disorder caused by a mutation in the D2 dopamine receptor on chromosome 11 and a locus on chromosome 7q21-q31. The authors tested linkage to the chromosome 7q candidate region in four families with either myoclonic dystonia (n = 3) or essential myoclonus (n = 1). Age at onset ranged from 0.5 to 38 years. Only four patients from two families had a positive response to alcohol. Lod scores were positive in all four families, suggesting that chromosome 7q21-q31 is a major locus for myoclonus-dystonia with several phenotypes.

Adult↗
PubMed2001

Human brain mapping in dystonia reveals both endophenotypic traits and adaptive reorganization.

Dystonia has a wide clinical spectrum from early-onset generalized to late-onset sporadic, task-specific forms. The genetic origin of the former has been clearly established. A critical role of repetitive skilled motor tasks has been put forward for the latter, while underlying vulnerability traits are still being searched for. Using magnetoencephalography, we looked for structural abnormalities reflecting a preexisting dysfunction. We studied finger representations of both hands in the primary sensory cortex, as compared in 23 patients with unilateral task-specific dystonia and 20 control subjects. A dramatic disorganization of the nondystonic hand representation was found in all patients, and its amount paralleled the severity of the dystonic limb motor impairment. Abnormalities were also observed in the cortex coding the dystonic limb representation, but they were important only in the most severely affected patients. The abnormal cortical finger representations from the nondystonic limb appear to be endophenotypic traits of dystonia. That finger representations from the dystonic limb were almost normal for the less severely affected patients may be due to intrinsic beneficial remapping in reaction against the primary disorder.

Adaptation, Physiological↗
PubMed2001

Idazoxan, an alpha-2 antagonist, and L-DOPA-induced dyskinesias in patients with Parkinson's disease.

Dyskinesia is a frequent and disabling side effect in patients with Parkinson's disease treated with chronic dopa-therapy. Preclinical data in the 1-methyl-4-phenyl-1,2,3,6,-tetrahydropyridine (MPTP) monkey suggest that alpha-2 antagonists may reduce dihydroxyphenylalanine (L-DOPA)-induced dyskinesia. We assessed, in a pilot randomised placebo-controlled study, the effects of single oral doses (10 mg, 20 mg, and 40 mg) of idazoxan, an alpha-2 antagonist, on motor parkinsonian disability and L-DOPA-induced dyskinesia following an acute oral challenge of L-DOPA in 18 patients with Parkinson's disease. The severity of L-DOPA-induced dyskinesia improved after 20 mg idazoxan pretreatment, while there was no concommittant deterioration in the antiparkinsonian response to L-DOPA. These results suggest that blocking alpha-2 receptors in patients with Parkinson's disease might improve L-DOPA-induced dyskinesia without the cost of a return of parkinsonian symptomatology. Further studies are required to assess whether this property could have potential therapeutic applications in the long-term management of dyskinetic patients with Parkinson's disease.

Administration, Oral↗
PubMed2001

Fast orthostatic tremor in Parkinson's disease mimicking primary orthostatic tremor.

Leg tremor during standing is a rare feature in idiopathic Parkinson's disease (PD). Tremor during standing usually has a low frequency (range, 4-6 Hz), similar to PD rest tremor frequency, and is improved by levodopa. We describe three cases of fast orthostatic tremor (FoT) of legs and trunk mimicking primary orthostatic tremor (OT) in patients treated with levodopa for PD. Asymmetrical akinetorigid syndrome was accompanied by a rest tremor in two cases. We obtained electrophysiological parameters by electromyographic (EMG) polygraphic recording after 16 hours withdrawal of antiparkinsonian treatment and at the maximal effect of levodopa in order to investigate the effect of dopaminergic stimulation upon such cases of orthostatic tremor in PD. Electrophysiological parameters of orthostatic tremor, especially frequency (range 14-18 Hz), were similar to that seen in POT. Severity of tremor was independent of seriousness and duration of PD. Levodopa had no effect either on the handicap due to OT or on the amplitude and frequency of the EMG OT activity. In contrast, mild improvement of OT was obtained with benzodiazepines in two cases and parkinsonian syndrome was levodopa-sensitive. These findings suggest that FoT in PD would not be directly controlled by the dopaminergic system. However, increased rhythmicities in basal ganglia or in cerebello-thalamic loops at the rapid frequencies range seen in PD could favor the emergence of a primary orthostatic tremor-like tremor in PD patients.

Aged↗
PubMed2001

[Dietary recommendations for pregnant women affected with phenylketonuria].

Prevention of embryopathy due to maternal phenylketonuria is possible thanks to a maternal-specific low-phenylalanine diet, which has to be started before conception and followed during the whole gestation. The setup of this diet implies knowing the recommended dietary allowances for normal pregnant women as well as for women with nutritional deficiencies. Women with phenylketonuria must be considered at risk for nutritional imbalance for two main reasons. First, most adult women with phenylketonuria have been on a vegetarian diet for many years without protein substitutes or medical control. Secondly, the strict diet for pregnant women with phenylketonuria may induce anorexia or nutritional deficits if it is not well tolerated or understood. Protein, iron, calcium, selenium, vitamin B 12 and caloric intakes are the most sensitive parameters. Close cooperation with an experienced medical and dietician team is required.

Adult↗
PubMed2001

[Infant formulas and soy protein-based formulas: current data].

For many years soy bean-based formulas (SBBF) were the only dietary product used for infants with cow's milk intolerance. At the present time, their place in infant nutrition is reduced as a result of the availability of new dietary products without lactose and/or cow's milk proteins and the recognition of soy bean protein allergy. There is no evidence that SBBF have any efficiency in infant colic. SBBF have no indication in the prevention of allergy, nor in premature infants' nutrition. Their main indication is the feeding of infants of vegetarian parents who do not want to use cow's milk products. Studies have shown that SBBF contain large quantities of phytoestrogens, particularly isoflavone. Because of experimental data suggesting a possible deleterious effect of phytoestrogens on the neuroendocrine maturation, the reduction of their content in SBBF must be considered.

Colic↗
PubMed2001

Increased plasma neurotensin concentrations in patients with Parkinson's disease.

Plasma neurotensin (NT) was measured by radioimmunoassay in propanol extracted and unextracted plasma from 16 parkinsonian patients (four before treatment) and 16 age and sex matched controls. Mean plasma NT concentrations were consistently higher in parkinsonian patients than in controls and higher in the four untreated patients than in levodopa treated patients suggesting that plasma NT measurement may represent an easy detectable additional index in diagnosing parkinsonism and provides a novel approach to research in this field.

Aged↗
PubMed2000

Longitudinal ocular motor study in corticobasal degeneration and progressive supranuclear palsy.

OBJECTIVE: To evaluate the usefulness of ocular motor information in the early diagnosis of corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP). METHODS: Seven PSP patients, six CBD patients, and three atypical CBD patients were followed longitudinally with repeated electrooculographic (EOG) recordings, at 6-month intervals, to search for features that could confirm or modify the diagnosis. Visually guided saccades and antisaccades were studied. Data from clinical evaluations were independently collected. RESULTS: PSP patients had decreased saccade velocity throughout the disease course. Patients with probable CBD showed preserved saccade velocity but important increased saccade latency ipsilateral to the apraxia side. Similar to patients with PSP, those with atypical CBD features exhibited clinically evident abnormalities of vertical saccades and early slowing of horizontal saccade velocity, but no increase in saccade latency or early square-wave jerks. When clinical "telltale signs" appeared and the clinical diagnosis was reviewed independent of EOG recording, the three patients with atypical CBD features were diagnosed as having PSP although new or overlapping syndromes cannot be excluded. CONCLUSIONS: Consecutive EOG recordings help diagnose atypical CBD and PSP disorders earlier.

Aged↗
PubMed2000

Analysis of riboflavin and riboflavin cofactor levels in plasma by high-performance liquid chromatography.

We describe an assay which determines simultaneously riboflavin (RF), flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) in plasma, using galactoflavin (GF) as an internal standard. The flavins were extracted on a C18 Sep-Pack cartridge after protein precipitation with 10% trichloroacetic acid, and were analyzed on a C18 RP-HPLC with 85% phosphate-magnesium acetate buffer (pH 3.4) and 15% acetonitrile. FAD, FMN, GF and RF extraction recoveries were 101.0-5.6, 97.0-6.5, 97.0-2.0 and 95.0-4.1%, and reproducibilities were 5.9, 6.8, 2.1 and 4.3%, respectively. FAD, FMN and RF values in infant and adolescent plasma were in the range 53.5-108.2, 9.0-25.1 and 12.7-53.4 nM, and 36.5-157.20, 7.1-24.6 and 8.2-57.8 nM, respectively. Using GF as an internal standard improved the quantification of these B2 vitamers.

Adolescent↗
PubMed2000

Frequency of the DYT1 mutation in primary torsion dystonia without family history.

BACKGROUND: Idiopathic torsion dystonia is a clinically and genetically heterogeneous movement disorder. A GAG deletion at position 946 of the DYT1 gene was the first mutation found, in early-onset dystonia, with an autosomal dominant transmission and reduced penetrance. OBJECTIVE: To evaluate the frequency of the DYT1 mutation in patients with idiopathic torsion dystonia but without a family history. DESIGN: Prospective cohort study. SETTING: Four botulinum toxin clinics in the Paris, France, area. PATIENTS: A French population of 100 patients with dystonia. MAIN OUTCOME: Frequency of the DYT1 mutation tested by polymerase chain reaction and enzyme restriction analysis for the 946 GAG deletion, and genotype-to-phenotype correlation. RESULTS: Only 5 mutation carriers were identified, 4 of whom were part of a group of 10 patients with generalized dystonia. Onset was between ages 5 and 12 years as in typical early-onset dystonia. All 4 patients had cranial muscle involvement, which is atypical for DYT1 mutation carriers. One had segmental dystonia. Molecular analysis of relatives in 2 families demonstrated that the lack of family history was due to reduced penetrance. CONCLUSIONS: For accurate diagnosis and genetic counseling, screening for the DYT1 deletion is of great interest in cases with generalized dystonia without a family history. In other cases, positive results are rare.

Adult↗
PubMed2000

Irregular jerky tremor, myoclonus, and thalamus: a study using low-frequency stimulation.

High-frequency thalamic stimulation alleviates tremor in Parkinson's disease (PD) and essential tremor (ET). The origin of thalamic myoclonus is unexplained and the effects of low-frequency thalamic stimulation on movement control are still unknown. We studied the effects of stimulation at a low frequency of 15 Hz in five drug-free patients (3 PD, 2 ET) 6 months after thalamic implantation of quadripolar electrodes (unilateral in four patients, bilateral in one patient). Clinical, electrophysiological, and videotaped assessment, using a monopolar 15 Hz frequency (3 V, 90 micros) stimulation current applied simultaneously through two adjacent contacts of the electrode, was performed. We observed myoclonus and irregular jerky tremor in the upper limb contralateral to the site of stimulation. The jerks lasted less than 200 ms, were irregular and not synchronous with stimulation, were superimposed on rest or postural tremor, and increased in response to tactile, proprioceptive, or vibratory stimuli. The fact that this complex movement disorder can be induced by low-frequency stimulation in the ventral intermediate nucleus (Vim) of the thalamus suggests that it results, at least partly, from dysfunction of the Vim and possibly adjacent nuclei of the thalamus.

Aged↗
PubMed2000

Plasma cholesterol and endogenous cholesterol synthesis during refeeding in anorexia nervosa.

Normal or high levels of cholesterol have been measured in patients with anorexia nervosa (AN). Given that cholesterol intake in AN is usually very low, the reasons for this anomaly are not clearly understood. We studied lipid and lipoprotein profiles and endogenous cholesterol synthesis, estimated by serum lathosterol, in a population of 14 girls with AN, before and during a period of 30 days refeeding. The initial body mass index (BMI) of the patients was 13.41+/-1.62 kg/m(2). No changes were observed during refeeding in endocrine parameters (ACTH, cortisol and estradiol). At Day 0 the lipids data measured here showed normal levels of triglycerides, and total cholesterol at the upper limits of the normal range (5.44+/-1 mmol/l). At this time, total and LDL cholesterol were negatively correlated with transthyretin and BMI. Serum lathosterol (a precursor in cholesterol synthesis pathway) increased significantly (5.99+/-1.75 (Day 0) vs. 8.39+/-2.96 (Day 30); P=0.02) while there was a significant decrease in apo B (0.79+/-0.33 (Day 0) vs. 0. 60+/-0.17 g/l (Day 30), P=0.02) with refeeding. Thus, patients with initial high cholesterol levels have the worst nutritional status and high cholesterol levels are not related to a de novo synthesis. This profile returns to normal with refeeding. An increase of cellular cholesterol uptake may be responsible for this apparently paradoxical evolution with increase of cholesterol synthesis and decrease of apo B during renutrition.

Adolescent↗