PubMed Health⌕ Search

Biomedical subjects

D Bequet

Publications and source records attributed to D Bequet.

At least 19 recordsLinked to original sources
PubMed2002

Preferential survival of an MBP-specific T cell clone in an HLA-DR2 multiple sclerosis patient.

Anti-myelin basic protein (MBP) autoreactive T cells play a key role in the pathogenesis of multiple sclerosis. Thus, we applied the Immunoscope strategy to cerebrospinal fluid (CSF) and peripheral blood lymphocytes (PBLs) of an HLA-DR2 patient. Both compartments showed major expansion for the V(beta)13S5 chain, which was associated in peripheral blood with significant proliferation of PBLs in response to MBP and the 84-102 HLA-DR2-restricted peptide. Sequencing revealed a unique nucleotide sequence in the CSF that gives rise to the amino acid sequence V(beta)13S5-RPGQGDQETQ-J(beta)2.5 if translated. This CDR3 sequence had already been reported to be reactive against the 84-102 peptide. This specific sequence was not detected in PBLs on day 0, whereas it was readily detectable on day 6 culture samples. Thus, cell culture may lead to enrichment in a T cell clone identified as autoreactive.

Adult↗
PubMed1999

[Superficial siderosis of the central nervous system].

We report five cases of superficial siderosis of the central nervous system. All patients developed progressive deafness and cerebellar ataxia associated with pyramidal tract signs or mental deterioration. The cerebrospinal fluid examinations usually revealed an elevated protein level, without other abnormalities. Magnetic resonance imaging typically showed a hypointense rim around the cerebral and cerebellar hemispheres, the brainstem and the spinal cord on T2-weighted images. A definite source of bleeding was only found in two patients. The literature on superficial siderosis is reviewed. The etiologies and the pathogenesis are discussed.

Adult↗
PubMed1996

Expansion of a recurrent V beta 5.3+ T-cell population in newly diagnosed and untreated HLA-DR2 multiple sclerosis patients.

We have used a PCR-based technology to study the V beta 5 and V beta 17 repertoire of T-cell populations in HLA-DR2 multiple sclerosis (MS) patients. We have found that the five MS DR2 patients studied present, at the moment of diagnosis and prior to any treatment, a marked expansion of a CD4+ T-cell population bearing V beta 5-J beta 1.4 beta chains. The sequences of the complementarity-determining region 3 of the expanded T cells are highly homologous. One shares structural features with that of the T cells infiltrating the central nervous system and of myelin basic protein-reactive T cells found in HLA-DR2 MS patients. An homologous sequence was not detectable in MS patients expressing DR alleles other than DR2. However, it is detectable but not expanded in healthy DR2 individuals. The possible mechanisms leading to its in vivo proliferation at the onset of MS are discussed.

Base Sequence↗
PubMed1996

The pattern of production of cytokine mRNAs is markedly altered at the onset of multiple sclerosis.

Using two independent PCR-based quantification techniques, we have determined the levels of IL1 beta, IL2, IL4, IL6, IL10, IFN gamma and TNF alpha mRNA in multiple sclerosis patients at the moment of diagnosis of the disease and prior to any immunosuppressive treatment. These patients exhibit markedly reduced IL2 and IL10 mRNA expression accompanied by decreased levels of TNF alpha mRNA. Our results add to the evidence that IL10 plays a role in multiple sclerosis and suggest that decreased production of this interleukin allows the proliferation of autoreactive T cells at the onset of the disease.

Acute Disease↗
PubMed1995

[Aluminum, hypothetic cause of Alzheimer disease].

A great deal of research has focused on aluminium as a putative causative factor in Alzheimer's disease. We measured by atomic absorption spectrophotometry aluminium levels in blood, urine and cerebrospinal fluid from 15 patients with Alzheimer's disease, compared with 20 control individuals. There were no statistically significant differences between the two groups. This suggests that aluminium is not a causative factor for Alzheimer's disease.

Aged↗
PubMed1995

[Cysticercosis: a frequent and redoubtable parasitic disease].

Cysticercosis is due to development of the larval form of Taenia solium, Cysticercus cellulosae in human tissue. It is widespread in developing countries especially in rural areas where it is endemic. Larval invasion of the central nervous system constitutes a dreadful complication. The incidence of this worldwide disease is underestimated in French-speaking Black Africa; the Indian ocean region has one of the highest incidences with Madagascar reporting a seroprevalence of 18% in 1994. It is estimated that 50 million people are infected in the world with 50,000 deaths a year. "Taenia solium carriers" play a major role in transmitting the disease to their immediate entourage even if the initial contamination of the carrier was due to infestation of pork. A wide range of epileptic manifestations can and often do constitute the first signs of neurocysticercosis which has been estimated to be the cause of epilepsy in two thirds of cases. This fact explains the numerous neuro-epidemiologic studies have been undertaken. In industrialized countries computeur tomodensitometry and magnetic resonance imaging are widely used for diagnosis and follow-up but immunologic diagnosis is most common in developing countries since medical imaging techniques are generally unavailable. The immuno-enzymatic method provides a basis for suspicion of infection and immuno-electrotranfer-blot allows diagnosis of progression of the disease to a stage at which cestocide treatment is active. New agents against cysticercoids that can circulate in the central nervous system (praziquantel, albendazole) have greatly improved the prognosis of neurocysticercosis. Massive single-dose treatment with praziquantel is especially useful in developing countries since taeniasis is rarely diagnosed in Taenia solium carriers. Persistent efforts to prevent contamination of pork have eradicated the infection in industrialized countries and diminished seroprevalence in others (Reunion Island). Cysticercosis is a major public health problem in developing countries. Systematic detection of the hotbeds and application of adequate control measures are needed.

Africa↗
PubMed1995

[Cadasil--a new model for subcortical dementia].

We report 3 cases of Cadasil with dementia. In the 3 cases, the dementia had a subcortical and frontal presentation. It associated behavioural symptoms, amnesia, executive functions disturbances, bradyphrenia, slowing of information processing and frontal symptoms, without aphasia, apraxia or agnosia. One patient showed overt dementia before any focal neurological sign. Imaging of the brain was consistent with subcortical infarcts and leukoencephalopathy, without involvement of the cerebral cortex. We suggest that dementia and psychoaffective disturbances are major diagnostic criteria for Cadasil. This pathology is probably a good model for the neuropsychological study and the physiopathological analysis of the concept of subcortical dementia.

Brain↗
PubMed1993

[Acute myelitis after vaccination against hepatitis B].

A 56-year old man was hospitalized for spasmodic paraparesis with sphincter disorders. After exclusion of spinal cord compression and all other inflammatory, infectious or neoplastic causes, the possibility of a connexion with an hepatitis B vaccination performed with a recumbent vaccine three weeks before the neurological disorders appeared was considered. The pathogenesis of such a myelitis remains uncertain. It is based on the possible reactivation of a dormant virus or a crossed antigenic reaction between a protein of the vaccine and the nervous system. The course of the disease is usually favourable. The frequency of this complication would be more accurately determined if all neurological manifestations occurring after hepatitis B vaccination were reported.

Acute Disease↗
PubMed1991

[Atrial electrophysiological study of unexplained cerebrovascular disorders].

The aim of this study was to detect possible atrial electrophysiological abnormalities in patients with unexplained embolic cerebrovascular accidents without overt atrial arrhythmias. This group was compared with normal controls and a group of patients with paroxysmal atrial fibrillation. Sixty-six patients were studied: Group I normal controls (N = 20); Group II patients with CVA (N = 26) and Group III, patients with paroxysmal atrial fibrillation (N = 20). Each group was divided into 2 subgroups according to age (over and under 45 years). The following parameters were taken into consideration: parameters correlated to atrial excitability (effective and functional refractory periods, adaptation of these refractory periods, intraatrial conduction--A1 and A2, S1A1, S2A2 intervals--, index of latent vulnerability); provocative testing by the extrastimulus technique; classical indices of atrioventricular conduction and sinus node function. In subjects over 45 years of age, the effective refractory periods were shorter in Group III (214 +/- 33 ms) and II (214 +/- 32 ms) than in the control Group I (248 +/- 21 ms), p less than 0.01. This difference was not apparent in younger patients. Inadaptation of the refractory periods was demonstrated equally in Groups II and III in all ages whilst the control subjects showed normal adaptation, p less than 0.05. Intraatrial A1 and especially A2 conduction was significantly prolonged in Group III (94.5 +/- 24 ms) and II (87 +/- 14 ms) compared with the control group (69 +/- 8 ms), p less than 0.01, especially in younger subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Isolation of HIV in a seronegative demented patient without symptoms of immune deficiency.

A 60-year-old male patient, originating from West Africa, developed acute and regressive neurologic symptoms associated with aphasia, apraxia, acalculia, behavioral impairments, and an epileptic phase. Eighteen months after the onset of the disease, the patient was almost normal. All along the clinical course, biological abnormality patterns were minor. We noted only a mild neutropenia in the blood. We also observed a weak lymphocytosis and elevated protein content in the cerebrospinal fluid. Electroencephalogram examination revealed slow waves which disappeared after remission. A weak ventricular dilatation was detected on CT scan. Neither vascular, nor tumoral, nor a classical infectious origin could be identified. While the patient was seronegative to HIV, a HIV-like virus was isolated twice from his peripheral blood lymphocytes during the disease. Eighteen months later, the patient remained seronegative. He developed neither AIDS nor immunodeficiency. The subtype of HIV has been isolated and characterized, and its neurotropism is being investigated.

Antibodies, Monoclonal↗