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Biomedical subjects

G Chazot

Publications and source records attributed to G Chazot.

At least 73 records · Page 4Linked to original sources
PubMed1995

Charcot-Marie-Tooth type 1B neuropathy: third mutation of serine 63 codon in the major peripheral myelin glycoprotein PO gene.

We report studies on two patients (a mother and her daughter) presenting with a Charcot-Marie-Tooth type 1 (CMT1) phenotype: low nerve conduction velocities of 13-15 m/s and an early onset at the age of walking. DNA analysis of the gene coding for the major peripheral myelin protein PO showed a new point mutation in exon 2, which resulted in substitution of a phenylalanine for serine at amino acid position 63 of PO. This is the third mutation reported at this codon, the two previously described leading to CMT1B (serine 63 deletion), or to Dejerine-Sottas disease (cysteine for serine 63 substitution), suggesting that different phenotypes can result from alteration of a single amino acid, depending on the type of the change involved.

Adult↗
PubMed1995

DNA analysis as a tool to confirm the diagnosis of asymptomatic hereditary neuropathy with liability to pressure palsies (HNPP) with further evidence for the occurrence of de novo mutations.

We performed DNA analysis in four families with hereditary neuropathy with liability to pressure palsy (HNPP). An interstitial deletion of the 17 p11.2 region was found in typically affected patients as well as in as yet asymptomatic patients. The opportunity for an individual genotyping permitted to ascertain a de novo deletion in one clinically affected case with no relevant familial history. DNA analysis thus becomes the most sensitive tool in diagnosing HNPP, since potentially affected patients may lack either informative familial history, or clinical symptoms or even suggestive EMG or histopathological data (tomaculas).

Adolescent↗
PubMed1995

Comparison of subcutaneous sumatriptan with usual acute treatments for migraine. French Sumatriptan Study Group.

246 migraine patients (International Headache Society definition, 1-6 severe attacks per month) were randomised into a multicentre, cross-over study comparing subcutaneous (s.c.) sumatriptan 6 mg administered by an auto-injector (Glaxo device) with usual acute migraine treatments. Patients were treated for 2 months or up to 12 attacks, and then crossed over to the alternative treatment for the same duration. Usual treatments were: analgesics (including combinations), 49%; ergotamine, 24%; NSAIDs 19%; DHE, 7%. Rescue medication was allowed 2 h after the first dose. Headache was assessed on a 4-point self-rating scale (0: none, 1: mild, 2: moderate, 3: severe). Other migraine symptoms were assessed as present or absent. Quality of life was assessed before the study and at the end of each treatment period. Two hundred and seventeen patients were eligible for the cross-over analysis. At 2 h post-dosing, an average of 78% of attacks per patient were successfully relieved (grade 3 or 2 to 1 or 0) by s.c. sumatriptan, compared with 34% for the usual treatments (p < 0.001) and 63% of attacks per patient were completely relieved (grade 0) by s.c. sumatriptan compared with 15% for the usual treatments (p < 0.001). Sumatriptan-treated patients used rescue medication for 19% of their attacks, compared to 59% for comparator drugs (p = 0.001). Results for patient preference were: s.c. sumatriptan, 85%; usual treatments, 10%; no preference, 5% (p < 0.001). Sumatriptan was significantly superior to comparator drugs for all other efficacy end-points (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

[Striato-pallido-dentate calcifications and acquired facial atrophy].

A family with two siblings presenting cerebral calcifications is reported. The sister was suffering from action tremor since the age of 10. The disease worsened by the age of 39. When aged 42, she was unable to walk and had severe rigidity and intellectual deterioration. She died at 43. The brother had mild debility. Action tremor started at the age of 14, without significant aggravation when seen at the age of 30. In both cases, brain CT scan showed calcifications of the dentate nuclei and cortical atrophy with ventricular enlargement. In addition, the sister had bilateral putaminal and pallidal calcifications. The other family members were unaffected and had normal CT scans. The nosology and the pathophysiology of this family report are discussed, particularly regarding the late occurrence of facial atrophy, reminiscent of the Cole-Engmann syndrome (Dyskeratosis Congenita).

Adult↗
PubMed1995

[Progressive lupus dementia. 2 cases with or without antiphospholipid antibodies].

Two cases of lupus dementia presented many points of particular interest: 1) the progressive installation of intellectual deterioration, inaugural for the first observation; 2) the diagnostic difficulties of neurolupus with the ARA criteria; 3) the appearance of cerebral magnetic resonance imaging with confluent hypersignals of the periventricular white matter on T2-weighted images; 4) the patholophysiological hypotheses: vascular disease? immunologic disease?; 5) the clinical improvement and SPECT amelioration for the second patient with corticosteroids.

Antibodies, Antiphospholipid↗
PubMed1994

Melatonin is able to influence its secretion in humans: description of a phase-response curve.

A single physiological dose of melatonin (20 micrograms for 3 h given intravenously at different times of the day (04.00-12.00, 16.00 and 20.00 h) was able to shift the endogenous plasma melatonin profile of healthy volunteers under entrained conditions according to a phase-response curve (PRC). ANOVA showed an effect of the time of administration on the onset, the acrophase or the offset of the melatonin profiles. These profiles were significantly delayed when the infusion was administered at 12.00 h and advanced when the infusion was given at 20.00 h. Further, the AUCs evaluated on the nocturnal melatonin profiles were increased after the 04.00 h infusion (+20.5%, p < 0.05), whereas they were decreased after the 12.00 h infusion (-20%, p < 0.05). Lastly, no alteration was observed for cortisol rhythm, whatever the time of melatonin administration. These results, which show that according to a PRC the system regulating melatonin secretion is sensitive to a single short-term administration of the hormone given at a low dose, support the paradigm of the endogenous synchronizer melatonin.

Adult↗
PubMed1994

Detection of deletion within 17p11.2 in 7 French families with hereditary neuropathy with liability to pressure palsies (HNPP).

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant peripheral neuropathy which is characterized by recurrent episodes of truncular palsies. We have analyzed the D17S122 locus in 7 French families, including 18 affected members, with microsatellite RM11GT and the RFLP probe VAW409R3a. Only one allele could be detected in all affected individuals with the highly polymorphic RM11GT marker. Allele segregation at D17S122 showed no contribution from the affected parent to the affected child, demonstrating that an interstitial deletion within the 17p11.2 region is associated with HNPP in the 7 families studied. This same region is duplicated, however, in another inherited neuropathy, Charcot-Marie-Tooth 1A disease. This would be the first example of two dominantly inherited diseases caused by a 'in mirror image' deletion/duplication mechanism where a gene dosage effect would be sufficient to produce two different phenotypes characterized by abnormal myelination of the peripheral nerves. The RM11GT microsatellite is an informative tool for the molecular diagnosis of HNPP.

Alleles↗
PubMed1993

Relief of akinesia by apomorphine and cerebral metabolic changes in Parkinson's disease.

The cerebral metabolic rate of glucose was measured in 14 Parkinson's disease patients with severe on-off fluctuations. Two positron emission tomography (PET) scans with [18F]fluorodeoxyglucose were performed, one after a challenge of subcutaneous apomorphine at a dose able to relieve akinesia within 15 min and the other with the vehicle. Apomorphine reduced glucose utilization by 4-6% in the lenticular nuclei and the occipital cortex and by 6-9% in the thalamic nuclei, but this effect was not statistically significant. Thus, central stimulation of dopamine receptors by apomorphine in advanced Parkinson's disease is not associated with cerebral metabolic changes as assessed by PET. Despite a dramatic improvement of the motor state, the global neuronal activity in the striatum and its downstream projections remains stable, suggesting an equilibrium between excitatory and inhibitory dopaminergic activities.

Aged↗
PubMed1993

The major peripheral myelin protein zero gene: structure and localization in the cluster of Fc gamma receptor genes on human chromosome 1q21.3-q23.

We have characterized the human gene encoding the major peripheral myelin protein zero (P0) and assigned it, by in situ hybridization, to the q21.3-q23 region of human chromosome 1. This region is known to contain a cluster of interspersed genes coding for the related human leukocyte receptors of the Fc portion of the immunoglobulin G (Fc gamma RI, II, III). This colocalization was refined by the finding of a yeast artificial chromosome (YAC) of the Centre d'Etude du Polymorphisme Humain (CEPH) library, hybridizing to the P0 and Fc gamma RIIA genes, demonstrating their physical linkage. These data may have important implications in demyelinating diseases studies like Charcot-Marie-Tooth disease type 1B (CMT1B).

Amino Acid Sequence↗
PubMed1993

[Treatment of Wilson's disease with zinc. 5 cases].

Zinc treatment of Wilson's disease was introduced by Schouwink en 1961 and is still uncommon in France. We evaluated the effectiveness and safety of zinc in 5 patients with Wilson's disease aged from 19 to 40 years. There were three neurological, one hepatic and one asymptomatic cases. Zinc was administered in doses of 120 to 272 mg/day, alone in 3 cases and combined with D-penicillamine in 2 cases. After 1 to 7 years of zinc therapy, our experience is consistent with data from recent literature and provides further evidence of zinc effectiveness. Zinc may be prescribed as first treatment in most patients, including asymptomatic cases. The only exception concerns patients with severe symptoms in whom it is recommended to combine zinc with D-penicillamine during the early phase of treatment for more rapid effectiveness. Because of its safety, zinc is particularly indicated in cases of intolerance to D-penicillamine and trien.

Adult↗
PubMed1992

Melatonin and jet lag: confirmatory result using a simplified protocol.

This study replicates the alleviation of jet-lag with melatonin in a simplified protocol for eastward flight. At 22-n hr (n is the time-lag between the North American departure point and France), subjects took either melatonin (8 mg, n = 15), or placebo (n = 15) on the day of the return flight and for 3 consecutive days. On day 8, self-ratings significantly discriminated between melatonin and placebo for global treatment efficacy, morning fatigue, and evening sleepiness.

Adult↗
PubMed1992

Charcot-Marie-Tooth disease from first description to genetic localization of mutations.

Charcot-Marie-Tooth disease is a hereditary motor and sensory neuropathy first described in 1886. Our increasing knowledge of this disease correlates well with the development of methods used in neurology over the past 100 years. Although its physiopathology and treatment is still not fully understood, current developments in techniques are opening the way to future discoveries. We have divided its history into three theoretical periods: the first from 1886 to 1956, which was devoted to clinical and pathological study of the disease; the second from 1956 to 1982, which saw the development of electromyography in the investigation of neuromuscular diseases; and the last and current period based upon genetic research, using the methods of molecular biology.

Charcot-Marie-Tooth Disease↗
PubMed1992

Progressive anarthria with secondary parkinsonism: a clinico-pathological case report.

The pathological process and lesion topography in patients with the syndrome of progressive aphasia are heterogeneous and few necropsy examination cases have been investigated. This is a case report of a 53 year old right handed man with progressive anarthria and secondary Parkinsonism over a period of six years. Positron emission tomography (PET) showed a decreased cerebral blood flow and metabolism in the frontal cortex, which was more pronounced on the left. Neuropathology disclosed a spongiform vacuolation in layer II of the frontal cortex, mostly in the Broca area, and neuronal loss in the substantia nigra. This original case reinforces the view that there are different entities of the syndrome of progressive aphasia which can be identified on the basis of clinical, neuroimaging and anatomical data.

Aphonia↗
PubMed1992

[Bilateral thalamic glioma. A clinicopathological study of 2 cases].

Two cases of bilateral thalamic glioma in a 70 year-old man and a 8 year-old boy, documented by MRI and pathological data are reported. Such tumors are rare. Early symptoms may be misleading, with intellectual impairment or psychiatric disorders together with a normal CT scan. MRI and pathological findings support the view that bilateral thalamic gliomas represent a particular clinico-pathological entity among thalamic tumors.

Aged↗
PubMed1992

[Juvenile arteriosclerotic leukoencephalopathy: anatomoclinical study of a case].

A 34-year old right-handed man was suffering from recurrent cerebro-vascular insults. CT-scans revealed several subcortical lacunar infarcts, and leukoaraïosis. Arteriography of the left and the right carotid arteries was performed respectively on the 4th and the 9th year of the disease, and did not elicit significant extracranial and intracranial vascular lesions. There were no arguments in favor of infectious, inflammatory, or auto-immune vascular diseases. The patient had tardive hypertension and dementia, and died at the age of 44. Pathological findings, limited to the brain and cervical spinal cord, revealed numerous ischemic lacunar infarcts. Histological lesions were consistent with the diagnosis of arteriosclerotic leukoencephalopathy. There were oedema, palor, and loss of myelin in the white matter, and nonspecific diffuse arteriosclerotic lesions that were particularly pronounced in the intimal part of the arterial wall. No inflammatory process nor amyloid deposits were found. Despite the onset of the disease in a young adult and the late occurrence of hypertension, our case report shares most of the pathological features of the Binswanger's type of arteriosclerotic encephalopathy.

Adult↗