Search PubMed⌕ Search

Biomedical subjects

A Tourbah

Publications and source records attributed to A Tourbah.

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

[Magnetic resonance spectroscopy in multiple sclerosis].

Magnetic resonance spectroscopy allows in vivo neurochemical exploration of multiple sclerosis (MS) lesions and normal appearing white matter on MRI. It gives insights into pathophysiology: inflammation (increase of choline), recent demyelination (increase in lipids and choline), axonal dysfunction (decrease of NAA), gliosis (increase of myoinositol). The spectroscopic profile of lesions is not specific to MS. Therefore MRI remains the first investigation to perform when MS is suspected. However, spectroscopy is a sensitive, reproducible, non invasive tool which may provide an index of activity. In the future, spectroscopy may contribute in homogenizing patient selection for clinical trials and might be used, in association with MRI, to evaluate therapeutic efficiency. Spectroscopy might also influence therapeutic choices by identifying the prevailing lesional mechanism: inflammation, demyelination, axonal destruction, or gliosis.

Brain↗
PubMed1999

[Multiple sclerosis: one or several diseases?].

The various clinical courses of multiple sclerosis (relapsing-remitting, primary progressive, secondary progressive, progressive-relapsing) are likely related to different severity or distribution of the main lesions that constitute the plaques (inflammation, demyelination, axonal injury and loss, necrosis). They might lead to different therapeutic approaches. Some cases of the other clinico-radiological or clinico-pathological variants (pseudo-tumoral, concentric sclerosis of Baló, acute disseminate encephalomyelitis, Devic's neuromyelitis optica) obviously share similar mechanisms with multiple sclerosis. Other cases are, on the contrary, linked to different diseases. Do the variants of multiple sclerosis could be the consequence of different diseases? This is, today, a highly speculative conjecture. The prevalent hypothesis suggests that the clinico-pathological heterogeneity of multiple sclerosis is linked to the variability of the reaction of the nervous tissue to an initial injury. This different vulnerability, that depends on unknown factors, would explain the variants of the disease.

Diagnosis, Differential↗
PubMed1999

Localized proton magnetic resonance spectroscopy in relapsing remitting versus secondary progressive multiple sclerosis.

OBJECTIVE: To determine the efficacy of MRS in discriminating between relapsing remitting (RR) and secondary progressive (SP) MS. METHODS: MRS at long and short echo times was carried out in 104 patients with MS stratified for clinical course (RR or SP), and the results were compared with those of 15 control subjects. Normal-appearing white matter (NAWM) was studied in 55 patients, and a high-T2-signal area on MRI in 49 others. RESULTS: At long echo times, there was a highly significant decrease in the ratios N-acetyl-aspartate/creatine (NAA/Cr) and NAA/ choline (Cho) in high-T2-signal areas and in the NAWM in patients with an SP course compared with control subjects and patients with an RR course. There was a significant negative correlation between these ratios and clinical disability measured by Expanded Disability Status Scale score, which was independent of disease duration. Discriminant values between patients with RR and SP courses were found in the NAWM (NAA/Cr = 1.75 and NAA/Cho = 1.5), but not in high-T2-signal areas. At short echo times, there was a significant increase in the ratio myoinositol/Cr in high-signal areas of patients with an SP course compared with control subjects, and the presence of abnormal resonances in the lesions and NAWM for free amino acids and lipids (in 30% and 8%, respectively) and GLX complex (glutamine, glutamate, gamma-aminobutyric acid; 16% and 20%, respectively). CONCLUSIONS: Studying normal-appearing white matter on MRI with MRS allows discrimination between relapsing remitting and secondary progressive patients. In the NAWM of patients with MS and an SP course, severe axonal loss/dysfunction is negatively correlated to clinical disability and independent of the duration of the disease.

Adolescent↗
PubMed1999

Encephalitis after hepatitis B vaccination: recurrent disseminated encephalitis or MS?

OBJECTIVE: To describe clinical and MRI features of patients with a disease suggestive of CNS inflammation after hepatitis B vaccination. METHODS: Eight patients with confirmed CNS inflammation occurring less than 10 weeks after hepatitis B vaccination are described. They received follow-up clinically and on MRI for a mean period of 18 months. RESULTS: Clinical and MRI findings were compatible with acute disseminated encephalomyelitis. However, clinical follow-up, repeated MRI, or both showed the persistence of inflammatory activity, which makes this encephalitis more suggestive of MS than of acute disseminated encephalomyelitis. CONCLUSION: The persistent inflammatory activity observed clinically and on MRI in these patients is comparable with that usually observed in MS. Epidemiologic studies are currently testing the hypothesis of a triggering role of hepatitis B vaccination in CNS demyelination.

Adult↗
PubMed1999

Normal-appearing white matter in optic neuritis and multiple sclerosis: a comparative proton spectroscopy study.

We investigated neurochemical abnormalities in the normal-appearing white matter (NAWM) on MRI of patients with optic neuritis (ON) and compared them to those of patients with multiple sclerosis (MS). Patients with ON (42) were classified into three groups according to abnormalities on brain MRI. Patients with MS (55) were divided in two groups: relapsing remitting MS (RRMS) and secondary progressive MS (SPMS). All patients underwent MRI of the brain and localised proton magnetic resonance spectroscopy (MRS) of NAWM. The results were compared to those of 15 controls. Patients with MS had significant abnormalities compared with controls and with patients with ON. Patients with RRMS and those with ON had comparable MRS parameters, while patients with SPMS had significant spectroscopic abnormalities in comparison with controls, but also with patients with RRMS. These changes consisted of a decrease in N -acetylaspartate, a neuronal marker, which may reflect axonal dysfunction and/or loss. MRS abnormalities were detected in 14 patients with ON (27 %). The main abnormalities consisted of a decrease in N -acetylaspartate, an increase in choline-containing compounds at long echo times, and the presence of free lipid peaks at short echo times. MRS of the NAWM on MRI may prove useful for detecting neurochemical brain abnormalities in ON not visible on MRI.

Adult↗
PubMed1999

Yield of fluid-attenuated inversion recovery in drug-resistant focal epilepsy with noninformative conventional magnetic resonance imaging.

PURPOSE: To determine the role in presurgical assessment and evaluate the yield of fast fluid-attenuated inversion recovery (FLAIR) sequences for patients with intractable partial epilepsy for whom conventional magnetic resonance imaging (MRI) was normal. MATERIAL AND METHODS: Forty patients were selected. Conventional MRI including spin echo T1-weighted sagittal images and fast spin echo T2-weighted axial images was normal in 33 patients and showed noninformative lesions in 7. Fast FLAIR and T2-weighted sequences were performed perpendicularly to the hippocampal long axis. RESULTS: Additional abnormalities were found in 40%. They were correlated with electroclinical data in 13 patients (32.5%) and not correlated or doubtful in 3 (7.5%). CONCLUSION: Fast FLAIR sequences brought congruent additional information in 32.5% cases and seemed useful in presurgical evaluation.

Adolescent↗
PubMed1999

[Four "alien" hands for two hands after a lesion in corpus callosum].

Callosal lesions, associated or not to internal frontal lesions, may produce different types of complex gestural behaviors. Four signs can be identified, each of which has been generally reported separately: the "alien hand" sign, the "diagnostic apraxia", the "wayward hand" and the "callosal apraxia". Some authors justify considering these signs as different entities, while others propose regrouping them either in an unique syndrome--the "alien hand"--or as two syndromes--the "frontal alien hand" and the "callosal alien hand". We present the observation of a patient who presented with the four mentioned syndromes in association. In this context, we review the clinical features of each of the four signs and the arguments supporting their individualization.

Agnosia↗
PubMed1998

Systemic autoimmune features and multiple sclerosis: a 5-year follow-up study.

OBJECTIVES: To evaluate in patients with multiple sclerosis (MS) the occurrence of clinical systemic signs and biological autoimmune abnormalities, including positive titers of antinuclear antibodies and antiphospholipid antibodies, suggestive of autoimmune diseases that may affect the central nervous system. Also, to compare the clinical and magnetic resonance imaging features and evolution of MS in patients with and without autoimmune abnormalities. DESIGN AND PATIENTS: Prospective study of 161 patients fulfilling the criteria of having probable or definite MS hospitalized in our institution between November 1990 and June 1992. RESULTS: Among the 161 patients, 84 (52.1%) had at least 1 clinical and/or biological general sign suggestive of an autoimmune disease; 64 were followed up for 4 to 5 years. The diagnosis of MS was confirmed in 50 patients and is still pending in 14 of them. No significant difference was found between patients with MS who were free of autoimmune features and those with autoimmune abnormalities (MS plus) concerning the age of disease onset, the presenting symptoms and signs, symptoms found on neurologic examination, and the course of the disease. For all patients with confirmed MS, general signs were found in 13.3%, positive titers of antinuclear antibodies in 26%, and positive titers of antiphospholipid antibodies in 6.2%. CONCLUSIONS: Patients with MS with autoimmune features, including those with titers of antinuclear antibodies of 1:100 or less and/or antiphospholipid antibodies, are not different than others with MS, and therefore should not be excluded from clinical trials.

Adolescent↗
PubMed1998

[Cognitive disorders in AIDS: clinical, virological and neuroradiological features].

HIV-associated neurocognitive disorders are mainly reported during the late stages of the disease, in deeply immunosuppressed patients Clinically, they present as a subcortical cognitive impairment, dominated by reduced psychomotor speed and memory deficit. Encephalic magnetic resonance imaging shows in most cases a diffuse leucoencephalopathy, and there is often a poor correlation between clinical status and neuroradiological findings. The diagnostic and prognostic value of HIV load in blood and cerebrospinal fluid is currently under investigation. Finally, the efficacy of new antiretroviral drugs on HIV dementia remains uncertain.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Inflammation promotes survival and migration of the CG4 oligodendrocyte progenitors transplanted in the spinal cord of both inflammatory and demyelinated EAE rats.

Oligodendrocyte progenitor CG4 cells were labeled with bisbenzimide and transplanted in the lumbar spinal cord of rats 15 to 17 days prior to the induction of experimental autoimmune encephalomyelitis (EAE). EAE was induced by immunization with the encephalitogenic peptide of myelin basic protein (amino acids 68-88; C1) in adjuvant, either alone or in combination with a single injection of an anti-myelin oligodendrocyte glycoprotein (MOG) antibody to enhance central nervous system (CNS) demyelination. In control animals without EAE, the survival and migration capacity of CG4 cells was minimal. In striking contrast, both the survival and migration of this oligodendrocyte progenitor cell line were greatly enhanced in animals with EAE. In both disease models, large number of CG4 cells were still found in the spinal cord 50 days after transplantation, by which time they had migrated up to 6 cm from the transplantation site. Migrating CG4 cells were found in the subpial space, around the ependyma and blood vessels, and as well as in the grey and white matter of the CNS parenchyma. In all these locations, the CG4 cells were often associated with reactive astrocytes. These data strongly support the concept that inflammatory responses within the CNS promote, rather than inhibit, the survival and migration of transplanted oligodendrocyte progenitors in the adult CNS.

Animals↗
PubMed1997

The natural course of cerebral lesions in Sneddon syndrome.

OBJECTIVES: To characterize the clinical, biological, and neuroradiological findings in Sneddon syndrome; to correlate magnetic resonance imaging abnormalities with disability, presence of hypertension and other vascular risk factors, presence of heart valvulopathy on echography, and titer of antiphospholipid antibodies; and to compare these findings in antiphospholipid-positive and antiphospholipid-negative patients. DESIGN: Retrospective review of the records of 32 consecutive patients with livedo reticularis and neurological events, followed up in our institution between January 1991 and August 1995. PATIENTS: Twenty-six patients (20 women and 6 men) who had at least 1 cerebral ischemic arterial event associated with generalized and pathological livedo reticularis. RESULTS: The age at the first cerebral ischemic event ranged from 22 to 58 years. Motor deficit was the most frequent sign (found in 73% of cases). Disability was found in 50%, systemic hypertension in 65%, heart valvulopathy in 61%, and antiphospholipid antibodies in 42% of cases. Patients were classified in 6 groups according to magnetic resonance imaging findings. No correlation was found between the presence of hypertension or other vascular risk factors, valvulopathy, antiphospholipids, and magnetic resonance imaging abnormalities. There was no significant difference between antiphospholipid-positive and antiphospholipid-negative patients except for the presence of antinuclear antibodies. There was a significant correlation between the extent of magnetic resonance imaging abnormalities and disability. CONCLUSION: The severity of the disease seems to be correlated with magnetic resonance imaging aspects, but not to the presence of antiphospholipid antibodies. Magnetic resonance imaging may help to understand the natural course of the cerebral involvement of the disease.

Adult↗
PubMed1997

Localized proton magnetic resonance spectroscopy in patients with adult adrenoleukodystrophy. Increase of choline compounds in normal appearing white matter.

OBJECTIVES: To describe the changes in the results of magnetic resonance imaging and spectroscopy occurring in the normal-appearing white matter of patients with adult adrenoleukodystrophy and to present evidence of a particular change that may serve as a marker for the follow-up of the disease. DESIGN: Neurologic, magnetic resonance imaging, and localized proton spectroscopic examinations were performed in 11 patients with adult adrenoleukodystrophy and compared with 11 sex- and age-matched controls. PATIENTS: Eleven patients with adult adrenoleukodystrophy participated in a trial of dietary therapy with glyceryl trioleate and glyceryl trierucate (Lorenzo's oil) in the Fédération de Neurologie and the Institut National de la Santé et de la Recherche Médicale, Unité 134, at the Hôpital de la Salpêtrière in Paris, France. RESULTS: The results of magnetic resonance imaging of the white matter were normal in 2 patients and showed areas of mild symmetrical hypersignals on T2-weighted images and fluid attenuated inversion recovery sequences, localized in the posterior white matter in 9 patients. The results of spectroscopy indicated that the peak of the area of choline-containing compounds was increased at long echo times in patients with adult adrenoleukodystrophy, which may reflect very long-chain fatty acid accumulation in this disease. The peak of the area of myo-inositol-containing compounds was increased at short echo times in patients with adult adrenoleukodystrophy, which may indicate a rise in this metabolite concentration. The N-acetylaspartate-creatine amplitude ratio was significantly decreased in patients with motor deficit. The significance of this finding remains to be established. CONCLUSIONS: The results of localized proton magnetic resonance spectroscopy show abnormalities in the cerebral white matter of patients with adult adrenoleukodystrophy, which may contribute to the understanding of the pathophysiologic characteristics of the disease. Although changes in the results of spectroscopy found in this disease are not specific, the increase of choline-containing compounds may reflect the accumulation of very long-chain fatty acids in the central nervous system. Localized proton magnetic resonance spectroscopy may prove a valuable technique, in addition to magnetic resonance imaging, for noninvasive investigation of patients with adult adrenoleukodystrophy undergoing future clinical trials.

Adrenoleukodystrophy↗
PubMed1997

Minimal surface: a useful paradigm to describe the deeper part of the corpus callosum?

The aim of this magnetic resonance imaging study was to find a geometrical characterization of the deeper part of the corpus callosum. Its shape was studied in 12 middle-aged persons free of white matter pathology. Profiles of curvatures were measured showing that this surface was close to a minimal one, especially at the genu and near the splenium. To assess the effect of a white matter pathology on these geometrical features, the same measurements were performed in an extra group of nine patients with definite multiple sclerosis. The hypothesis of curvatures profiles parallelism for the two groups could be rejected at the 0.05 confidence level for the mean curvatures but not for the Gaussian ones. Curvatures profiles may give indications on balance between the cortex and the fiber bundles growth rates during the development and on large scale modifications co-occurring with multilocular white matter pathologies.

Adult↗
PubMed1997

Clinical and molecular features of spinocerebellar ataxia type 6.

The mutation involved in spinocerebellar ataxia type 6 (SCA6) is a small CAG expansion in the alpha-1A subunit of the voltage-dependent calcium channel gene. We looked for this mutation in 91 families with autosomal-dominant cerebellar ataxias and found that SCA6 is a minor locus in our series (2%) and is rare in France (1%). Furthermore, we did not detect the SCA6 mutation on 146 sporadic cases with isolated cerebellar ataxia or olivopontocerebellar atrophy. The normal and expanded alleles ranged from 4 to 15 and 22 to 28 CAG repeats, respectively, and age at onset was correlated to CAG repeat length (r = -0.87). In contrast with other SCA, the expanded allele was stable during transmission. Clinically, SCA6 patients (n = 12) presented with moderate to severe cerebellar ataxia with a lower frequency of associated signs compared with other SCA and a mean age at onset of 45 +/- 14 years (range, 24 to 67). MRI showed extensive cerebellar atrophy but not of the brainstem or cerebral cortex.

Adult↗
PubMed1997

[Clinical, biological and neuroradiological aspects of Sneddon's syndrome: 26 cases].

Sneddon syndrome is characterized by the association of livedo reticularis and cerebrovascular ischemic events. Clinical and MRI aspects are described in 26 patients with Sneddon syndrome. MRI features were classified in 6 groups according to the aspect and topography of the lesions. No correlation was found between the presence of vascular risk factors, valvulopathy or antiphospholipid antibodies and the presence of dementia or MRI lesions. There was a significant correlation between MRI extension of the lesions and clinical disability. Clinical course and MRI findings are presented according to the treatment.

Adult↗