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Biomedical subjects

M Clanet

Publications and source records attributed to M Clanet.

At least 55 records · Page 3Linked to original sources

MRI of intramedullary sarcoidosis: follow-up of a case.

Intramedullary lesions are infrequently the first manifestation of sarcoidosis. We present clinical and radiological follow-up of spinal cord sarcoidosis in a 68-year-old woman, mimicking an intramedullary tumour. MRI revealed an unusual area of low signal intensity on T2-weighted spin-echo images at the core of the lesion, consistent with calcification. Clinical and MRI follow-up showed progressive resolution of the intraspinal lesion, except for the calcification, with oral steroid therapy.

Aged↗

Human Toxocara infection of the central nervous system and neurological disorders: a case-control study.

Infection with Toxocara canis is a common world-wide human helminthiasis, which rarely elicits central nervous system (CNS) impairment. A case-control study to investigate this discrepancy was carried out, in which the cases were 27 adult neurological inpatients for whom a definite aetiological diagnosis was lacking, and for whom positive immunodiagnosis of toxocariasis had been obtained, both in cerebrospinal fluid (CSF) and in serum. Two control groups were used. Controls were adult inpatients with other neurological diseases who had no evidence of T. canis infection of the CNS. Multivariate logistic regression analysis did not reveal any positive relation between case status and clinical signs. A significant association was observed between case status and an elevated CSF cell count. Rural residence, ownership of dogs, and dementia were shown to be risk factors for toxocaral infection of CNS. These results suggest that migration of T. canis larvae in the human brain does not frequently induce a recognizable neurological syndrome but is correlated with the association of several risk factors including exposure to dogs, a status possibly responsible for repeated low-dose infections.

Analysis of Variance↗

Therapeutic effect of mitoxantrone combined with methylprednisolone in multiple sclerosis: a randomised multicentre study of active disease using MRI and clinical criteria.

OBJECTIVE: To evaluate the efficiency of mitoxantrone in multiple sclerosis. METHODS: Forty two patients with confirmed multiple sclerosis, selected as having a very active disease on clinical and MRI criteria were randomised to receive either mitoxantrone (20 mg intravenously (IV) monthly) and methylprednisolone (1 g iv monthly) or methylprednisolone alone over six months. In the steroid alone group five patients dropped out due to severe exacerbation. RESULTS: Blinded analysis of MRI data showed significantly more patients with no new enhancing lesions in the mitoxantrone group compared with the steroid alone group, (90% v 31%, P < 0.001). In the mitoxantrone group there was a month by month decrease almost to zero in the number of new enhancing lesions, and in the total number of enhancing lesions, whereas both remained high in the steroid alone group. The differences were significant for both indices at all months from 1-6. Unblinded clinical assessments showed a significant improvement in change in EDSS at months 2-6 in the mitoxantrone group, with a final mean improvement of more than one point (-1.1 v + 0.3; P < 0.001). There was a significant reduction in the number of relapses (7 v 31; P < 0.01), and an increase in the number of patients free of exacerbation (14 v 7; P < 0.05). CONCLUSION: In this selected group of patients with multiple sclerosis with very active disease, mitoxantrone combined with methylprednisolone was effective in improving both clinical and MRI indices of disease activity over a period of six months whereas methylprednisolone alone was not. Further double blinded long term studies are needed to properly evaluate the effect of mitoxantrone on progression in disability.

Adjuvants, Immunologic↗

Identification of a Val 145 Ile substitution in the human myelin oligodendrocyte glycoprotein: lack of association with multiple sclerosis. The Réseau de Recherche Clinique INSERM sur la Susceptibilité Génétique à la Sclérose en Plaques.

Myelin/oligodendrocyte glycoprotein (MOG) is a major target antigen in experimental autoimmune encephalomyelitis and it has been suggested that it may as well play a key role in the demyelination process in multiple sclerosis (MS). As MOG variants could be pathogenic in autoimmune demyelinating diseases of the central nervous system, we analysed the coding sequence of MOG in MS patients and described a G-->A transition occurring in exon 3 of the human MOG gene. The mutation predicts that isoleucine substitutes for a valine at codon 145 (Val 145 Ile) in the transmembrane region of the protein. This is the first aminoacid substitution reported in human MOG. The polymorphism can be detected by restriction enzyme digestion of genomic DNA or reverse-transcribed PCR amplified products, making it a simple tool to detect a potential implication of MOG alleles in susceptibility to MS by association study. The analysis of 83 unrelated MS patients and 82 unrelated healthy controls showed that the polymorphism is found in similar proportions in MS patients (18%) and controls (14.6%). It is therefore unlikely that the MOG Val 145 Ile variant is responsible for genetic susceptibility to MS.

Amino Acid Sequence↗

[Ischemic cerebrovascular complications in Rendu-Osler disease: a case].

Rendu-Osler disease is a familial disorder transmitted as an autosomal dominant trait of high penetrance. It is characterized by telengiectasias of the skin, mucous membranes and viscera, associated with recurrent bleedings. Neurological complications (brain abcesses and hemorrhagic manifestations) occur in 10% of the patients. Neurological symptoms are often associated with arteriovenous fistula of the lung (50%). Ischaemic strokes occuring in such patients with an hemorrhagic disease while unfrequent, have been described. The pathophysiology of stroke in that case remains unclear. Polycythemia causing hyperviscosity, air embolism following hemoptysis, paradoxical embolism through right-to-left shunt have been proposed. We report a new case of ischaemic strokes occuring in a caucasian forty-year-old woman, with Rendu-Osler disease (familial history, epistaxis, telengiectasias) and with an arteriovenous malformation of the right lung. She presented two strokes and one transient ischaemic attack. Her pulmonary malformation was occluded by embolization. The role of arteriovenous malformation in the pathophysiology of strokes is discussed.

Adult↗

Levorotatory form of 5-hydroxytryptophan in Friedreich's ataxia. Results of a double-blind drug-placebo cooperative study.

OBJECTIVE: To study the effect of the levorotatory form of 5-hydroxytryptophan on the cerebellar symptoms of Friedreich's ataxia. DESIGN: Cooperative double-blind study of the levorotatory form of 5-hydroxytryptophan vs placebo. SETTING: Twelve centers in research hospitals. PATIENTS: Twenty-six patients were included; 19 completed the study (mean +/- SD age of patients, 25.9 +/- 8.1 years). Of these 19 patients, eight were treated with placebo and 11 were treated with the drug. MAIN OUTCOME MEASURES: A semiquantitative scale for kinetic and static ("postural") cerebellar functions and quantitative measurements of time in standard tests that evaluated stance, speech, writing, and drawing. RESULTS: In the active treatment group, a significant decrease of the kinetic score was observed (P = .03), indicating an improvement in coordination. CONCLUSIONS: These results demonstrated that the levorotatory form of 5-hydroxytryptophan is able to modify significantly the cerebellar symptoms in patients with Friedreich's ataxia. However, the effect is only partial and not clinically major.

5-Hydroxytryptophan↗

Abnormal vestibuloocular reflex cancellation in multiple system atrophy and progressive supranuclear palsy but not in Parkinson's disease.

We have measured the gain of the vestibuloocular reflex (VOR) in darkness and its cancellation by fixation in 37 patients with Parkinson's disease (PD), 26 patients with multiple system atrophy (MSA), 11 patients with progressive supranuclear palsy (PSP), and 19 normal volunteers. The capacity to cancel the VOR by fixation (VOR cancellation) was significantly reduced in the MSA and PSP patients compared with the PD and normal subjects (p < 10(-4)). A VOR cancellation < 90% (i.e., the mean VOR cancellation of the normals--2 SD) was present in four PD patients, 23 MSA patients, and 11 PSP patients. This criteria distinguished PD and MSA with a 89% sensitivity and a 89% specificity. Our results demonstrate that the VOR cancellation is impaired in most patients with MSA and PSP but not with PD. In MSA patients, the abnormal VOR cancellation is probably not related to the nigrostriatal dopaminergic deficit and more likely reflects a cerebellar dysfunction. Impaired VOR cancellation is a clinical criteria to differentiate MSA and PSP from PD.

Age Factors↗

Myelin oligodendrocyte glycoprotein (MOG) gene polymorphisms and multiple sclerosis: no evidence of disease association with MOG.

The region surrounding the myelin oligodendrocyte glycoprotein (MOG) gene, located telomeric to the major histocompatibility complex on chromosome 6, was shown to contain three highly informative microsatellites. To examine the potential role of variants of the MOG gene in susceptibility to multiple sclerosis, these CA-repeat polymorphic markers were characterized on a sample of 169 multiple sclerosis patients and 173 healthy unrelated individuals by a method combining fluorescence labelling of PCR products and use of an automated DNA sequencer. Both patients and controls lived in the southwest of France (in the Pyrénées-Atlantiques) and had similar ethnic background. The distribution of the MOG haplotypes was not significantly different in the two groups (P = 0.38). This is not in favour of the implication of the MOG gene in the genetic component of multiple sclerosis, unless different independent mutations have occurred within this gene.

Base Sequence↗

Three highly polymorphic microsatellites at the human myelin oligodendrocyte glycoprotein locus, 100 kb telomeric to HLA-F. Characterization and relation to HLA haplotypes.

The MOG locus, located on chromosomal bands 6p21.3-p22 and mapped about 100 kb telomeric to HLA-F, was isolated from cosmid ICRFc109A2434 and shown to contain three microsatellites. These CA-repeat polymorphic markers were characterized in a sample of 173 healthy unrelated individuals and 84 DNAs from the HLA Workshop reference panel, by a method combining fluorescence labeling of PCR products and use of an automated DNA sequencer. For the three markers, frequencies of heterozygotes are well predicted from allele frequencies by the Hardy-Weinberg rule, which suggests that problems of allele nonamplification are unlikely. Typing of cell lines homozygous in the HLA region allowed unambiguous definition of 81 HLA-MOG haplotypes and showed that several HLA ancestral haplotypes extended to the MOG region. The high degree of polymorphism (59%, 51%, and 81% at the three loci, respectively, and 87% at the haplotype level) makes these new markers informative for association or linkage studies with diseases such as hemochromatosis or multiple sclerosis, and for studies aimed at precisely delineating the site of crossover in chromosomes in which recombination occurred in the distal part of the HLA class I region.

B-Lymphocytes↗

Treatment of hemifacial spasm with botulinum toxin. Value of preinjection electromyography abnormalities for predicting postinjection lower facial paresis.

Thirty-two patients with hemifacial spasm were treated with 61 botulinum toxin (BT) injections. Some patients had post-BT lower facial paresis (LFP+group) while others did not suffer this side effect (LFP-group). Abnormal electromyography (EMG) recordings were more frequent in the LFP+ group (6/11) than in the LFP- group (3/21; p < 0.05). This result suggests that an EMG performed before any BT injection could detect the patients with a higher risk for this side effect. The first dose of BT might be lowered in such cases.

Aged↗

Peduncular 'rubral' tremor and dopaminergic denervation: a PET study.

Lesions causing so-called rubral tremors frequently involve the substantia nigra or the nigrostriatal fibers, suggesting dopaminergic denervation as possibly contributory. We examined this hypothesis using PET and [18F]-fluorodopa in six patients with a contralateral tremor following a peduncular lesion. The denervation revealed by PET was even more marked than in severe parkinsonian patients. All patients showed partial to complete improvement with levodopa therapy. PET evaluation of D2-receptors with [76Br]bromolisuride showed no asymmetry of the D2 binding despite the important asymmetry of 18F-fluorodopa uptake. Our results indicate an important involvement of the nigral dopaminergic system in peduncular tremors that appears to be independent of postsynaptic dopamine receptors.

Adult↗

Antivertigo medications and drug-induced vertigo. A pharmacological review.

The approach to drug treatment of vertigo is almost exclusively symptomatic. There are 3 major goals for drug treatment of vertigo. The first one is to eliminate the hallucination of motion. Drugs with vestibular 'suppressant' properties are used for this purpose. The major vestibular suppressants are anticholinergic and antihistamine drugs. The second goal is to reduce the accompanying neurovegetative and psychoaffective signs (nausea, vomiting, anxiety). Antidopaminergics are used for this purpose. The third goal is to enhance the process of 'vestibular compensation' to allow the brain to find a new sensory equilibrium in spite of the vestibular lesion. Until now, the pharmacological manipulation of vestibular compensation has been assessed in animals but not in humans with vestibular lesions. Vestibular suppressant drugs delay rather than enhance compensation. A variety of other drugs is also used in the treatment of vertigo, including benzodiazepines, histaminergic agents, sympathomimetics and calcium antagonists. Their mechanism of action is poorly understood. The data base derived from clinical trials evaluating antivertigo medications is often questionable because of methodological limitations. This explains why habits of prescription are mainly empirical, and why striking differences can be noticed from one country to another. We can hope that new treatments may emerge from the present interest in receptor subclasses and neuromodulators of the vestibular system, and we must be ready to evaluate these potential new pharmacological agents with reliable clinical methods in humans.

Animals↗

[Myasthenia induced by tiopronin in the treatment of rheumatoid arthritis].

Myasthenia gravis (MG) is a well known side-effect of D-Penicillamine used in the treatment of rheumatoid polyarthritis. Tiopronin is another drug available in France, which can also induce MG. Drug-induced MG are characterized by frequent involvement of facial and oropharyngeal muscles. Moreover, the generalization is scarce and the outcome always quite good. No thymoma is present, anti-acetylcholine receptors antibodies are often highly positive. Furthermore, some HLA phenotypes are most frequently found among patients with drug-induced MG suggesting a genetic predisposition. This observation underlines the interest of careful management of patients treated by tiopronin.

Aged↗

[Potential value of hyperbaric oxygenation in the treatment of post-radiation myelopathies].

We describe 9 patients with radiation myelopathy treated by hyperbaric oxygenation (HBO). In this retrospective study, six out of nine (66%) could have been stabilized or improved by HBO. Physiopathological mechanisms of radiation myelopathy remain controversial and incompletely known. We discuss the putative mechanisms of the beneficial action of HBO on radiation myelopathy. Controlled studies are required to clarify the interest of HBO in this disease.

Adult↗

[Vertigo in non-vascular diseases of the central nervous system].

Excluding vascular involvement, vertigo due to a central vestibular syndrome reflects a median or paramedian lesion of the brain stem or the cerebellum. Recurrent attacks of vertigo usually occur with peripheral lesions. Persistent acute vertigo with peripheral destruction can reveal ischemia of the brain stem. Central positional vertigo is rare and has symptomatology that is different from that of benign positional vertigo. Persistent instability has a symptomatology that is more difficult to analyse and is usually associated with a central vestibular syndrome when it is organic. Diagnosis of a central vestibular syndrome is based on detection of well-defined clinical or electronystagmographic signs of which abnormal nystagmus is primordial. Some of them such as inferior vertical nystagmus or dissociated nystagmus can localise the site. MRI has become the diagnostic procedure which is best adapted for identifying the most frequent aetiologies such as tumors, congenital malformations and multiple sclerosis.

Central Nervous System Diseases↗