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H Chabriat

Publications and source records attributed to H Chabriat.

At least 37 records · Page 2Linked to original sources
PubMed2000

Decreased hemispheric water mobility in hemiplegic migraine related to mutation of CACNA1A gene.

We report a reversible reduction of water diffusion in the brain during a prolonged attack of hemiplegic migraine. The patient had a sporadic mutation of the CACNA1A gene. The diffusion changes were observed in the contralateral hemisphere 3 and 5 weeks after the onset of hemiplegia. These results suggest the occurrence of hemispheric cytotoxic edema during severe attacks of hemiplegic aura. The mechanisms underlying such ultrastructural modifications are unknown but an abnormal release of excitatory amino acids can be hypothesized.

Adult↗
PubMed2000

Cerebral hemodynamics in CADASIL before and after acetazolamide challenge assessed with MRI bolus tracking.

BACKGROUND: White matter lesions in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) are underlaid by severe ultrastructural changes of the arteriolar wall. Although chronic ischemia is presumed to cause the tissue lesions, the pattern of perfusion abnormalities and hemodynamic reserve in CADASIL, particularly within the white matter, remains unknown. METHODS: We used the MRI bolus tracking method in 15 symptomatic patients with CADASIL (5 with dementia) and 10 age-matched control subjects before and 20 minutes after the intravenous injection of acetazolamide (ACZ, 17 mg/kg). Cerebral blood flow (CBF), blood volume (CBV), and mean transit time (MTT) were calculated both in the cortex and in the white matter according to the singular value decomposition technique. Perfusion parameters were obtained in regions of hyperintensities and within the normal-appearing white matter as observed on T2-weighted images. Analysis was performed with both absolute and relative (region/whole brain) values. RESULTS: A significant reduction in absolute and relative CBF and CBV was found within areas of T2 hyperintensities in white matter in the absence of significant variations of MTT. This reduction was more severe in demented than in nondemented patients. No significant change in absolute CBF and CBV values was observed in the cortex of patients with CADASIL. A decrease in relative CBF and CBV values was detected in the occipital cortex. After ACZ administration, CBF and CBV increased significantly in both the cortex and white matter of affected subjects, but the increase in absolute CBF was lower within areas of increased signal on T2-weighted images in patients than in the white matter of control subjects. CONCLUSIONS: In CADASIL, both basal perfusion and hemodynamic reserve are decreased in areas of T2 hyperintensities in the white matter. This hypoperfusion appears to be related to the clinical severity. The significant effect of ACZ on CBF and CBV suggests that cerebral perfusion might be increased using pharmacological vasodilation in CADASIL.

Acetazolamide↗
PubMed2000

[CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy): clinical features and neuroimaging].

Recently identified in a french family, CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy) is a generalised disease of small arteries, largely predominating in the brain. Its clinical manifestations start during mid-adulthood and include recurrent ischaemic subcortical events, attacks of migraine with aura, severe mood disorders, subcortical dementia, and, at magnetic resonance imaging, widespread leuko-encephalopathy. There is so far no specific treatment and the mean duration of the disease is 20 years. CADASIL is most frequently a familial disorder with an autosomal dominant mode of transmission. Its responsible gene, Notch 3, is located on Chromosome 19. By the identification of its gene, CADASIL, (which is now known to affect over 400 families worldwide) is a unique variety of cerebro-vascular disease, affecting mainly the subcortical white matter.

Dementia, Multi-Infarct↗
PubMed2000

[CADASIL: genetics and physiopathology].

CADASIL, an autosomal dominant adult onset arteriopathy causing stroke and dementia in humans, is underlaid by a non atherosclerotic non amyloid angiopathy involving mainly the media of small cerebral arteries; it is characterized by major lesions of vascular smooth muscle cells. Using a positional cloning approach, we mapped CADASIL locus on chromosome 19 and identified the mutated gene as being Notch3. This gene, previously unknown in humans, encodes for a large transmembrane receptor belonging to the Notch/lin12 gene family which are known to be involved in cell fate specification during development. Genetic analysis of more than 120 CADASIL unrelated families allowed us to show that these mutations are highly stereotyped and affect only the extra cellular domain of the protein. On the basis of these data, a molecular diagnostic test has been set up and is now widely required by clinicians involved in the diagnosis of vascular leukoencephalopathies. Using this test, we recently showed that CADASIL can also occur in patients who do not have any affected relative due to the existence of notch3 de novo mutations. As a first step to investigate the molecular and cellular mechanisms leading from Notch3 mutations to CADASIL phenotype, we analyzed by in-situ hybridization and immunohistochemistry the pattern of expression of this gene. Notch3 expression is highly restricted to the vascular smooth muscle cell in normal human adults. In CADASIL tissues there is a dramatic accumulation of the extracellular domain of the protein which suggests that one of the main mechanisms of CADASIL involves anomalies in the proteolytical cleavage and clearance of this protein. These data provide important clues to the mechanisms of this condition and current work should lead in the next future to a complete understanding of CADASIL and set up the basis of a rational therapeutical approach of this condition.

Dementia, Multi-Infarct↗
PubMed1999

Safety and efficacy of combined lysine acetylsalicylate and metoclopramide: repeated intakes in migraine attacks.

The efficacy of the combination of lysine acetylsalicylate and metoclopramide in the treatment of migraine attacks has been established previously. The value of repeated doses of such a combination has been reported in a recent study. The purposes of this open-label study performed by general practitioners on a very large sample of migraine sufferers were to confirm that repeated doses of the combined treatment are efficient and well-tolerated, and to assess the efficacy of treatment according to the initial headache intensity. Three thousand seven hundred twenty-seven general practitioners entered 7259 migraine sufferers. Patients had to use a first dose, the efficacy of which was assessed 2 hours later. In the case of failure, they were then able to take a second dose and possibly a third dose, 2 hours after the second, in the case of persistent failure. Twelve thousand five hundred sixty-two migraine attacks were analyzed. Tolerance, as assessed by the patients, was considered as good in more than 85% of attacks, whatever the number of doses utilized. Five hundred thirty-five adverse effects were reported after the use of 22,697 sachets. Of 12,515 attacks documented for efficacy, patients considered the treatment as good or excellent in 80% of attacks treated with one dose, 55% of those treated with two doses, and 27% of those treated with three doses. Relief of headache (reduction of its severity from grade 3 or 2 to 1 or 0) was observed in 51% of episodes after the first sachet, 51% of episodes treated with a second sachet, and 56% of episodes treated with a third sachet. The first dose of treatment was found to be more effective when the initial severity of the headache was moderate (improvement in 66% of attacks) than when it was severe (improvement in 30% of attacks). Efficacy appeared to increase according to the number of doses when headache was initially severe. This trial confirms that repeated doses of this combination is well-tolerated and effective. Our results show that repeated doses are particularly useful for severe attacks.

Adult↗
PubMed1999

Precipitating factors of headache. A prospective study in a national control-matched survey in migraineurs and nonmigraineurs.

Prospective studies of precipitating factors in migraine are rare. Mig Access is a national control-matched survey conducted to evaluate the access of migraineurs to health care in France. This study allowed us to screen prospectively some precipitating factors of headache in migraineurs and in nonmigraineurs. Three hundred eighty-five migraineurs (group 1) and 313 nonmigraineurs (group 2) kept a diary for a 3-month period (a total of 35,805 day in group 1 and 29,109 days in group 2). Precipitating factors were reported for each headache period. Headache intensity was self-assessed during each headache period using a visual analog scale of 0 to 100. Headache was reported on 4274 days (12%) in group 1 and on 602 days (2%) in group 2. Headache intensity was greater in group 1 (39 +/- 20 versus 32 +/- 19, P < .05). The most frequent precipitating factors (reported at least once by more than 10% of subjects [range 18% to 80%] in both groups) were fatigue and/or sleep, stress, food and/or drinks, menstruation, heat/cold/weather, and infections in both groups. All these factors except infections were reported to cause headache more frequently in migraineurs than in nonmigraineurs. Mean intensity of headache related to fatigue and/or sleep, stress, food and/or drinks, hot/cold weather, and menstruation varied from 37 to 43 in migraineurs and from 29 to 35 in nonmigraineurs. Headache with the highest mean intensity was due to infections in the two groups (47 +/- 20 in group 1, 45 +/- 23 in group 2). Our results support that endogenous factors are the most frequent triggers of headache in migraineurs. The most frequent precipitating factors of headache appear identical in migraineurs and in nonmigraineurs. Our results suggest that similar triggers could precipitate headache of different type in these two populations.

Adult↗
PubMed1999

Clinical severity in CADASIL related to ultrastructural damage in white matter: in vivo study with diffusion tensor MRI.

BACKGROUND AND PURPOSE: CADASIL is a newly recognized cause of subcortical ischemic strokes that progressively leads to dementia associated with pseudobulbar palsy and severe motor disability. This deleterious progression and the severity of clinical presentation are widely variable among affected subjects. The exact role played by MRI white-matter abnormalities, a hallmark of the disease, in the severity of the clinical phenotype remains poorly understood. METHODS: To address this issue, we used diffusion tensor imaging (DTI), a new MRI technique highly sensitive to white-matter microstructural changes, in 16 symptomatic patients and 10 age-matched controls. Mean diffusivity and anisotropy of diffusion were measured within hyperintensities identified on T2-weighted images (T2WI) and outside these lesions on 4 slices at the level of centrum semiovale. RESULTS: We found a 60% increase of water mean diffusivity and a parallel loss of diffusion anisotropy in hyperintensities identified on T2WI. The same pattern of diffusion changes, but of lesser intensity, was found in the normal-appearing white matter on T2WI. Mean diffusivity in regions with increased signal on T2WI was higher in patients with severe clinical disability compared with those with no or mild deficit (1.33+/-0.11 versus 1.13+/-0.11 10(-3) mm(2)/s, P<0.01). Furthermore, diffusion measured within T2 hyperintensities correlated with both the Mini-Mental State Examination and Rankin scale scores. In patients with a severe clinical status, the increase of water diffusion in these regions exceeded 70% in comparison with values obtained in the normal white matter in control subjects. CONCLUSIONS: These results indicate that DTI is able to detect important ultrastructural changes in regions with increased signal on T2WI and within the normal-appearing white matter in CADASIL. The diffusion changes might be related to both neuronal loss and demyelination. The degree of the underlying ultrastructural alterations is related to the severity of the clinical status with a possible threshold level of white-matter damage above which severe neurological impairment may occur in this disease. DTI appears to be a promising technique for monitoring disease progression in CADASIL.

Adult↗
PubMed1999

Brain stem MRI signal abnormalities in CADASIL.

BACKGROUND: We recently showed that the severity of MRI signal abnormalities increases with age in CADASIL, an arteriopathy due to mutations of notch 3 gene on chromosome 19. Previous results also suggest that the various hemispheric subcortical areas have a different vulnerability to ischemia in this disease. The distribution of the lesions at the brain stem level has not yet been reported. CASE DESCRIPTIONS: We reviewed the MRIs of 68 affected patients having signal abnormalities in the hemispheric white matter to assess the distribution and clinical consequences of brain stem signal abnormalities in CADASIL. We found hypersignals on T2-weighted images in the brain stem in 45% of the subjects. The pons was more frequently involved (100%) than the mesencephalon (69%) and the medulla (35%). Hyposignals on T1-weighted images, at the brain stem level, were observed only in two thirds of these subjects. The lack of signal abnormalities reaching the brain stem surface and the absence of cerebellar lesions were noteworthy. CONCLUSIONS: Brain stem signal abnormalities observed in CADASIL are found in regions irrigated only by perforating arteries. These results support parallel observations made for CADASIL-associated signal abnormalities in the cerebral hemispheres and emphasize the importance of the angioarchitecture of the cerebral vasculature to explain why a condition characterized by a systemic vessel wall pathology is manifested only as a brain disease.

Brain Stem↗
PubMed1998

SPECT study of a German CADASIL family: a phenotype with migraine and progressive dementia only.

OBJECTIVE: We describe the clinical, molecular, genetic, MRI, and SPECT features of a German family with autosomal dominant migraine and dementia, mapping to the cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) locus. We studied the correlation of cerebral blood flow, MRI, and cognitive function. BACKGROUND: CADASIL is a small-vessel disease of the brain mapped to chromosome 19p13.1. Mutations of the Notch3 gene cause this disorder. Most phenotypes are characterized by transient ischemic attacks (TIAs) and lacunar strokes leading to dementia. Migraine is frequent. A single photon emission computed tomographic (SPECT) study of this disorder has not yet been published. METHODS: We studied 13 individuals clinically and performed neuroimaging studies with MRI and SPECT. RESULTS: Genetic analysis strongly supported linkage to the CADASIL locus, and the disease haplotype was found in six individuals. Analysis by single-strand confirmation polymorphism did not identify Notch3 mutations. All affected individuals had MRI white matter hyperintensities and four individuals had additional basal ganglial signal abnormalities. Four affected individuals had migraine, two of whom had slowly progressive dementia. TIAs, stroke, and focal neurologic signs were absent. Cerebral blood flow reduction in SPECT studies of affected individuals matched with MRI signal abnormalities. Cognitive impairment was linked to signal abnormalities and hypoperfusion in the basal ganglia. Demented patients had a pattern of frontal, temporal, and basal ganglial hypoperfusion. CONCLUSIONS: We describe a CADASIL phenotype that is characterized by the absence of focal neurologic symptoms and present the first SPECT study of this disorder.

Adolescent↗
PubMed1998

Patterns of MRI lesions in CADASIL.

OBJECTIVE: To investigate the location and severity of MRI signal abnormalities in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). BACKGROUND: One hallmark of this arteriopathy due to mutations of Notch 3 gene is the presence of MRI signal abnormalities in both symptomatic and asymptomatic patients. METHODS: MRIs of 75 patients (43 with symptoms) were reviewed by a neuroradiologist masked to their clinical status. After assessing the presence of MRI lesions on T1- and T2-weighted images (T1-WI, T2-WI) in different subcortical regions, the severity of hyperintensities on T2-WI was scored using a global rating scale and a regional semiquantitative scale in the periventricular white matter (PV), deep white matter (WM), basal ganglia (BG), and infratentorial areas (IT). RESULTS: Sixty-eight patients (90%) had hyperintensities on T2-WI located in the white matter, more frequent in PV (96%) and WM (85%) than in the superficial white matter (25%). Hyperintensities also occurred in BG (60%) and brainstem (45%). Forty-seven patients (62%) presented with hypointensities on T1-WI. In one-third of the affected individuals, white matter hyperintensities occurred in the absence of small deep infarcts on T1-WI. The frequency and severity scores calculated for PV, WM, BG, or IT hyperintensities increase dramatically with age. These scores were higher in symptomatic compared with asymptomatic gene carriers. Dementia, Rankin score > 1, or both occurred only in the presence of diffuse white matter signal abnormalities. CONCLUSION: Our results suggest that different subcortical areas have different vulnerabilities to ischemia in CADASIL. The age effect we observed may show an accumulation of lesions with aging during the course of the disease. A prospective study is needed to investigate if the rating of MRI lesions is of prognostic value in CADASIL.

Adult↗
PubMed1998

[Hemicerebral atrophy and epilepsy in an adult].

We report the case of a 49 year-old man who presented a partial status epilepticus with left-sided clonic seizures after the occurrence of a left cerebral hematoma. The patient had left-side hemiplegia that progressively recovered in 3 months. Neuroimaging studies revealed a moderate cerebral atrophy on the right side and crossed cerebellar atrophy. Six years later, he had a partial status epilepticus with left hamiconvulsions leading to permanent left hemiplegia. The right cerebral and the left cerebellar atrophy observed one year later were significantly increased. Cerebral hemiatrophy associated with epilepsy in adulthood is exceptional. Our case suggests that the occurrence of partial status epilepticus, even during adulthood, may aggravate cerebral hemiatrophy formally silent.

Atrophy↗
PubMed1997

Strong clustering and stereotyped nature of Notch3 mutations in CADASIL patients.

BACKGROUND: CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy) is commonly overlooked or misdiagnosed owing to its recent identification and its variable mode of presentation. The defective gene in CADASIL is Notch3, which encodes a large transmembrane receptor. To set up a diagnostic test and to delineate the Notch3 domains involved in CADASIL., we undertook mutations analysis in this gene in a group of CADASIL patients. METHODS: 50 unrelated patients with CADASIL and 100 healthy controls were screened for mutations along the entire Notch3 sequence, by means of single-strand conformation polymorphism, heteroduplex, and sequence analysis. FINDINGS: Strongly stereotyped mis-sense mutations, located within the epidermal-growth-factor-like (EGF-like) repeats, in the extracellular domain of Notch3, were detected in 45 patients. Clustering of mutations within the two exons encoding the first five EGF-like repeats was observed (32 patients). All these mutations lead to loss or gain of a cysteine residue and therefore to an unpaired number of cysteine residues within a given EGF domain. None of these mutations was found in the 100 controls. INTERPRETATION: Because of the strong clustering and highly stereotyped nature of the pathogenetic mutations detected in CADASIL patients, and easy and reliable diagnostic test for CADASIL is feasible. The findings suggest that aberrant dimerisation of Notch3, due to abnormal disulphide bridging with another Notch3 molecule or with another protein, may be involved in the pathogenesis of this disorder.

Case-Control Studies↗
PubMed1997

Notch3 mutations in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a mendelian condition causing stroke and vascular dementia.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited condition whose key features include recurrent subcortical ischemic events, migraine attacks and vascular dementia in association with diffuse white-matter abnormalities seen on neuroimaging. Pathologic examination shows multiple small deep cerebral infarcts, a leukoencephalopathy and a nonatherosclerotic nonamyloid angiopathy involving mainly the media of small cerebral arteries. To progress in understanding the pathophysiological mechanisms of this condition, we undertook the identification of the mutated gene. We mapped the CADASIL gene on chromosome 19p13.1. More than 120 families have been referred to our lab. Genetic linkage analysis of 33 of these families allowed us to reduce the size of the genetic interval to less than 1 cM and to demonstrate the genetic homogeneity of this condition. In the absence of any candidate gene, we undertook positional cloning of this gene. We identified, within the CADASIL critical region, the human Notch3 gene, whose sequence analysis revealed deleterious mutations in CADASIL families co-segregating with the affected phenotype. These data establish that this gene causes CADASIL. Identification of the CADASIL gene will provide a valuable diagnostic tool for clinicians and could be used to estimate the prevalence of this underdiagnosed condition. It should help in the understanding of pathophysiological mechanisms of CADASIL and vascular dementia.

Adult↗
PubMed1997

[CADASIS. Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalophathy].

CADASIL is an inherited arterial disease of the brain with an autosomal dominant pattern of transmission. The mapping of the affected gene in 1993 allowed us to describe the natural history of the disease. In some patients, the disease starts with attacks of migraine with aura at a mean age of 30 years. The most frequent clinical manifestations are subcortical transient ischemic attacks or completed strokes usually occurring between 40 and 50 years of age which are sometimes associated with severe mood disturbances. The disease leads about two decades later to death after a variable period of subcortical dementia associated with pseudobulbar palsy and urinary incontinence. In one given family, the severity of the clinical presentation varies among the affected subjects. MRI is always abnormal in symptomatic subjects. It shows more or less confluent hypersignals on T2-weighted images in white-matter and basal ganglia and hyposignals on T1-weighted images in the same regions corresponding to small infarcts. These signal abnormalities are even observed a long time before the onset of clinical manifestations as they are present in totally asymptomatic young family members. Histologic studies show a widespread palor of white-matter and multiple small infarcts in the white-matter and basal ganglia underlaid by a small artery disease of the brain. Electron microscopy studies show that the media of the white-matter and leptomeningeal small arteries is thickened by a granular, eosinophilic and non-amyloid material of undetermined origin close to the smooth muscle cells. These ultrastructural wall abnormalities have been observed in other arteries, particularly in muscular and skin arteries. Mutations of Notch3 gene located on chromosome 19 are responsible for the disease. The diagnosis should be discussed in subjects with a history of unexplained subcortical ischemic strokes, attacks of migraine with aura, mood disorders of subcortical dementia whenever associated with MRI signal abnormalities in white-matter and basal ganglia.

Brain↗
PubMed1996

A human homolog of bacterial acetolactate synthase genes maps within the CADASIL critical region.

CADASIL, a recently identified autosomal dominant condition characterized by the recurrence of subcortical infarcts leading to dementia, was previously mapped to chromosome 19p13.1 within a 2-cM interval, D19S226-D19S199. No recombination event was observed with D19S841, a highly polymorphic microsatellite marker isolated from a cosmid mapped to this region. We recently identified within this cosmid a conserved sequence that we used to screen a fetal brain cDNA library and isolated an ubiquitous and abundantly transcribed gene. We did not detect any mutation of this gene in CADASIL patients, suggesting that it is not implicated in this disorder. Interestingly, this gene encodes a putative protein homologous to several thiamine pyrophosphate-binding proteins previously identified in bacteria, yeast, and plants. The proteins with the highest degree of similarity were the acetolactate synthase enzymes which, in prokaryotes, are involved in the branched chain amino acid biosynthetic pathway, raising fascinating questions on the yet unknown function of this gene in mammals.

Acetolactate Synthase↗
PubMed1996

Notch3 mutations in CADASIL, a hereditary adult-onset condition causing stroke and dementia.

Stroke is the third leading cause of death, and vascular dementia the second cause of dementia after Alzheimer's disease. CADASIL (for cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) causes a type of stroke and dementia whose key features include recurrent subcortical ischaemic events and vascular dementia and which is associated with diffuse white-matter abnormalities on neuroimaging. Pathological examination reveals multiple small, deep cerebral infarcts, a leukoencephalopathy, and a non-atherosclerotic, non-amyloid angiopathy involving mainly the small cerebral arteries. Severe alterations of vascular smooth-muscle cells are evident on ultrastructural analysis. We have previously mapped the mutant gene to chromosome 19. Here we report the characterization of the human Notch3 gene which we mapped to the CADASIL critical region. We have identified mutations in CADASIL patients that cause serious disruption of this gene, indicating that Notch3 could be the defective protein in CADASIL patients.

Adult↗