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Biomedical subjects

P Lebon

Publications and source records attributed to P Lebon.

At least 127 records · Page 7Linked to original sources
PubMed1988

Interferon-gamma and Ia antigen are present on astrocytes in active chronic multiple sclerosis lesions.

Using immunocytochemical techniques, presence of interferon (IFN)-gamma, IFN-alpha and Class II major histocompatibility (MHC) antigen (HLA-DR, Ia) was evaluated in active central nervous system (CNS) lesions of 11 patients with chronic multiple sclerosis (MS) and the findings were correlated with a detailed analysis of inflammatory cells. Both IFN-gamma and Ia antigen were detectable on astrocytes at the edge of active chronic MS lesions and in the adjacent normal-appearing white matter, where CD4+ (helper/inducer) T cells and interleukin-2 receptor (IL-2R)-positive cells were also found. IFN-alpha was predominantly seen on Ia-positive macrophages and not on astrocytes. Astroglia in the inactive lesion center and in normal CNS parenchyma were unreactive for both types of IFN and Ia antigen. These findings suggested that similar to the situation in vitro, IFN-gamma can also induce Ia-expression on astrocytes in vivo. Via local antigen presentation, IFN-gamma might thus play an important role in the development of MS lesions, while IFN-alpha might be involved in local immunosuppression.

Astrocytes↗
PubMed1987

Soluble IL-2 receptors in acute and subacute encephalitis.

Elevated levels of soluble interleukin-2 receptors were present in the serum from patients with acute primary and postinfectious encephalitis and subacute sclerosing panencephalitis. In addition, soluble interleukin-2 receptors were detected in the cerebrospinal fluid from patients with acute primary encephalitis. Their presence in the cerebrospinal fluid was not explained by damage to the blood-brain barrier and our data attest to their local origin. This suggests that it may be possible in certain neurological diseases to detect cerebral T-lymphocyte activation through a specific marker in the cerebrospinal fluid.

Adult↗
PubMed1987

Paralytic poliomyelitis in vaccinated children.

Paralytic poliomyelitis were observed in two healthy children who both had previously received four doses of standard inactivated poliovaccine (IPV). These children, whose immune defenses were normal, failed to respond to IPV. This absence of antibody response might be related to an insufficient antigenicity of inactivated vaccines, justifying the extensive use of the more potent IPV, now produced on continuous cell lines.

Child, Preschool↗
PubMed1987

IgG (Gm) allotypes in acute measles encephalomyelitis and subacute sclerosing panencephalitis.

Gm phenotype or haplotype frequencies are known to be increased in some neurological diseases involving dysregulation(s) of the immune system. Therefore, possible associations between acute measles encephalitis (AME) or subacute sclerosing panencephalitis (SSPE) and alleles of the Gm system were investigated by comparison of children (41 AME subjects and 62 SSPE subjects) with 378 ethnically and geographically matched controls. Although the Gm3;..;11 haplotype displayed a very low frequency among SSPE children, no statistically significant departure in the distribution of Gm phenotypes could be evidenced between AME or SSPE, and controls. A further appraisal of combined Gm and HLA phenotypes may be warranted in both diseases since Gm/HLA interactions have been demonstrated in other immunopathological conditions.

Adolescent↗
PubMed1987

[Late onset cystinosis. Apropos of a case].

This report concerns a new case of late onset cystinosis with heavy proteinuria. Renal biopsy showed focal segmental glomerular hyalinosis and the usual tubular and glomerular lesions of cystinosis. The pathogenesis of glomerular hyalinosis remains unclear.

Adolescent↗
PubMed1986

Subacute sclerosing panencephalitis: detection of measles virus RNA in appendix lymphoid tissue before clinical signs.

An appendix removed 15 days before onset of symptoms of subacute sclerosing panencephalitis was examined retrospectively for measles virus ribonucleic acid (RNA). Tissue sections hybridised in situ to a cloned measles virus probe of deoxyribonucleic acid specific for nucleocapsid protein showed that many cells of the lymphoid tissue contained measles virus RNA. In contrast, only a few infected lymphoid cells were detected in three out of six seropositive controls and none in three seronegative infants. A widespread chronic viral infection of the immune system, established after measles, may promote or even initiate nerve cell infection in subacute sclerosing panencephalitis.

Appendix↗
PubMed1986

Interferon pretreatment lowers the threshold for maximal heat-shock response in mouse cells.

Interferons (IFNs) are proteins which have antiviral and antiproliferative properties and are known to affect various immunological processes. Some of these activities have been shown to be potentiated by increased temperatures. When cells are subjected to a rise in temperature, the synthesis of the heat-shock proteins (HSPs) is 'switched on.' In this report we demonstrate a synergistic effect of IFN and stress (arsenite treatment or elevated temperature) on the heat-shock response. On the one hand, IFN pretreatment enhances the accumulation of HSP mRNAs and the corresponding protein synthesis after a mild stress and, on the other hand, it amplifies the decrease of the total protein synthesis after a severe stress. Thus in IFN pretreated cells the range of temperatures leading to the heat-shock response is shifted towards common physiological values.

Animals↗
PubMed1986

HLA antigens in acute measles encephalitis.

The frequency of HLA-A, B, DR antigens was studied in 24 patients with acute measles encephalomyelitis compared to 1926 control subjects. The results demonstrated no association between the susceptibility to the disease and HLA markers. However, DR4 was observed in 6 patients out of 10 who developed intrathecal secretion of specific antimeasles immunoglobulins, while absent in 4 patients, who did not (p less than 0.04). Further studies on a larger series are needed.

Child↗
PubMed1986

[Overload histiocytosis in 2 hemodialyzed patients. Possible role of dextran 40].

The authors report two cases of singular overloading histiocytosis, observed in patients treated with regular dialysis and undergoing feverish cachectic disease. The observations of the two patients show a same histiocytosis infiltration of ganglions, liver, muscles, lung, pleura and pericardium, consisting in an accumulation of PAS positive intracytoplasmic substance, refringent at polarisation, microcrystalline on electron microscopy and on ionic analysis. Clinical likeness appears with PVP thesaurismosis but the histochemical findings are different. A favorable issue occurred with corticosteroïd treatment. Nature of PAS positive substance is uncertain. An exogenous origin is undoubted, and some elements call for the responsibility of dextran 40.

Adult↗
PubMed1986

[Prospective study of 59 cases of viral meningitis in children. Clinical and virologic diagnosis. Epidemiology and physiopathology].

In a prospective 2 year study of 59 cases of childhood meningitis, mumps was the most common etiological virus (39%), followed by enterovirus (27%). The analysis of the cases suggested that a diagnosis of the infectious agent may be arrived at using clinical data such as the degree of nuchal rigidity, the age of the patients, and the presence of associated parotiditis or macular rash. Pleiocytosis in the CSF was higher and included a larger percentage of lymphocytes during mumps meningitis than during enterovirus meningitis. Mumps or enterovirus were isolated in the CSF of 23% (mumps) and 27% (enterovirus) of the patients. Alpha interferon which was acid labile was detected in the CSF of 89% and 63% respectively of patients with mumps and enterovirus meningitis.

Antibodies, Viral↗
PubMed1985

Detection of measles virus RNA in lymphocytes from peripheral-blood and brain perivascular infiltrates of patients with subacute sclerosing panencephalitis.

To clarify the relation between lymphocytes and measles virus in subacute sclerosing panencephalitis, we used in situ hybridization and a cloned measles virus DNA probe, specific for nucleocapsid protein, to detect measles virus RNA sequences in circulating lymphocytes and brain perivascular cuffs of patients with subacute sclerosing panencephalitis. Seventy to 90 per cent of peripheral mononuclear cells from three such patients were found to contain measles virus RNA sequences. In contrast, only a few infected cells were observed in four seropositive adults (0.1 to 5 per cent) and three age-matched children (10 to 15 per cent) used as controls. In one sample of brain tissue from a patient with subacute sclerosing panencephalitis, viral RNA sequences were also detected in nerve cells and in numerous cells from the perivascular infiltrates. In contrast, no hybridization was observed in brain tissue from a patient with herpetic encephalitis and from a patient with postlymphoma encephalitis. We conclude that measles virus has a strong tropism for lymphocytes and nerve cells in subacute sclerosing panencephalitis and that lymphocytes may be involved in the pathogenesis of the disease.

Adult↗