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Biomedical subjects

O Lees

Publications and source records attributed to O Lees.

17 recordsLinked to original sources
PubMed1995

Activation of the endothelium by IL-1 alpha and glucocorticoids results in major increase of complement C3 and factor B production and generation of C3a.

Constitutive secretion of complement C3 and factor B by the endothelial cell (EC) is lowered by therapeutic concentrations of glucocorticoids such as hydrocortisone or dexamethasone, whereas regulatory protein factor H production is increased by these hormones. In contrast, the proinflammatory cytokine IL-1 alpha has a stimulatory effect on C3 and factor B secretion by the endothelium and an inhibitory effect on factor H secretion. In this study, we examined the combined effect of IL-1 alpha and glucocorticoids on C3 and factor B expression by the endothelial cell. When dexamethasone or hydrocortisone were added to IL-1 alpha, significant potentialization of IL-1 alpha-induced stimulation of C3 and factor B production was observed, occurring at various concentrations of either stimuli. Dose-response experiments indicate that, in vitro, optimal concentrations are in the range of 10(-7) to 10(-5) M for dexamethasone and 50-200 U for IL-1 alpha. In contrast, dexamethasone counteracts, in an additive way, the inhibitory effect of IL-1 alpha on regulatory complement protein factor H production by EC. Such a potentialization between glucocorticoids and IL-1 alpha was not observed for another marker of endothelial activation, IL-1 alpha-induced stimulation of coagulation tissue factor expression. The association of glucocorticoids and IL-1 alpha therefore appears to be a specific and major stimulus for the secretion of complement C3 and factor B, two acute-phase proteins, by the endothelium. As a result of the in vitro endothelium stimulation by glucocorticoids and IL-1 alpha, C3a is generated in the vicinity of the endothelial cell. This study further suggests that complement activation, with its deleterious consequences, may result from the stimulation of endothelium in situations where high levels of IL-1 alpha and endogenous glucocorticoids coexist, such as in septic shock.

Cells, Cultured↗
PubMed1993

Clinical applications of flow cytometry in hematology and immunology.

Rapid developments in computer technology combined with new fluorescent dyes and monoclonal antibody production have led to the development of a powerful tool: flow cytometry. The techniques of flow cytometry can be applied in a wide clinical field, from routine tasks to research in immunology and hematology. The availability of automated instruments and standardized sample preparation methods have led to its daily clinical use, helping diagnosis, prognosis or monitoring therapy. Further advances will be made with the introduction of multi-parametric analysis ie quantification of antigen expression of cell surface antigens.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Analysis of T cell receptors in rheumatoid arthritis: the increased expression of HLA-DR antigen on circulating gamma delta+ T cells is correlated with disease activity.

The phenotypic characteristics of peripheral blood T cells, isolated from 37 rheumatoid arthritis (RA) patients and 17 healthy controls were determined with special emphasis on gamma delta+ T cells and CD4-CD8- alpha beta+ T cells. Two- and three-colour automated flow cytometry analyses were performed using a panel of MoAbs directed against differentiation antigens and T cell receptor molecules. The results demonstrated: (i) no significant difference between the percentages of CD4-CD8- alpha beta+ T cells in patients and controls; (ii) a significant decrease of the gamma delta+ T cell level in the peripheral blood of RA patients relative to controls; (iii) phenotypic abnormalities of circulating gamma delta+ T cells in RA patients suggestive of an activation status in vivo. These abnormalities included a significant reduction in the density of the T cell differentiation antigen CD3 and an increase in the expression of HLA-DR antigen. The level of circulating HLA-DR+/gamma delta+ T cells was significantly higher in patients with active disease. HLA-DR+/gamma delta+ T cells were also present in the synovial fluid obtained from three patients with an active disease. In addition, preliminary experiments showed that the activated gamma delta+ T cells were predominantly V delta 1. Taken together, these data support the involvement of gamma delta+ T cells in the pathogenesis of RA.

Adult↗
PubMed1988

Del(14)(q22) in diffuse B-cell lymphocytic lymphoma.

Some recurrent chromosomal abnormalities have recently been found to be associated with distinctive histologic subtypes of non-Hodgkin's lymphoma (NHL). In a study of 62 patients with NHL whose karyotypes was determined at diagnosis, 3 patients were found to have a deletion of the long arm of chromosomes 14 at band 22 (del[14][q22]). All had a diffuse lymphoma with generalized lymphadenopathy and bone marrow involvement. All three lymphomas were of B-cell origin, as shown by the presence of surface immunoglobulin and monoclonal antibody phenotyping. For each patient, a trisomy 12 was associated with del(14)(q22) in a clone. These data suggest that del(14)(q22), perhaps in association with trisomy 12, could identify a subtype of NHL and that band 22 of chromosome 14 may be implicated in the B-cell ontogeny.

Antigens, Differentiation↗
PubMed1986

[Acute systemic lupus erythematosus after thymectomy for myasthenia. Sequential study of lymphocyte subpopulations].

A 35 year-old woman developed severe systemic lupus erythematosus 9 years after thymectomy for myasthenia gravis. "Seric Thymic Factor" (STF) was low; T helpers subset, T helpers/T suppressors ratio and to a lesser extent T suppressors subset were decreased. Suppressor cell function investigated by Concanavaline A lymphocyte reactivity was low. Under cyclophosphamide, plasmapheresis and steroids all clinical and biological symptoms improved but STF remained low; T helpers, T suppressors subsets and T helpers/T suppressors ratio increased but did not reach the normal range. Statistical and immunological arguments suggest that the association between systemic lupus erythematosus and myasthenia gravis did not occur only by chance. Moreover, thymectomy might have played a role by decreasing the number and function of some subpopulations of lymphocytes.

Acute Disease↗
PubMedDate not supplied

[Dysglobulinemic neuropathy. Apropos of IgD myeloma manifested by mononeuritis].

The authors report a case of IgD myeloma of which the initial symptom was a mononeuritis and the biological, immunological and ultrastructural study performed about this case. Then are reviewed the mechanisms, proved or hypothetical, by which are actually explained the event of neuropathies within lympho-plasmocytic disorders.

Amyloidosis↗
PubMedDate not supplied

[Thyroid pathology and lymphoproliferative diseases].

Four cases are reported, of an association between a thyroidal illness (1 hypothyroidism, 3 hyperthyroidism) on one hand, and a lymphocytic proliferation and/or monoclonal gammapathy on the other. The following findings: HLA B8 or DrW3 in 3, antithyroid antibodies at a very high level in 2, and thyroid stimulating immunoglobulin in 2 support the conclusion of thyroidal diseases of auto-immune nature. Simultaneous appearance of both thyroidal and hematologic illness favors the hypothesis of a non coincidental association. A direct thyroidal activity of the monoclonal paraprotein has been found only once among the 4 published and our 2 cases in which it has been studied. A more likely link would be a common physiopathology: a functional deficiency of T suppressor lymphocytes allowing the proliferation of a cellular clone producing an abnormal immunoglobulin, would also allow the development of a thyroidal illness when favored by a genetic predisposition.

Aged↗