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B Pegourie

Publications and source records attributed to B Pegourie.

10 recordsLinked to original sources
PubMed2000

Investigation of electron-distribution function and dynamo mechanisms in a reversed-field pinch by analysis of hydrogen-pellet deflection

In reversed-field pinches, two different mechanisms have been proposed to explain the dynamo process which drives the poloidal current needed to sustain the magnetic configuration: the kinetic dynamo theory and the magnetohydrodynamic (MHD) dynamo theory. Experimentally, they can be distinguished by the radial behavior of the electron distribution function. In this Letter the trajectory deflection of frozen hydrogen pellets has been used as a diagnostic of suprathermal electrons in the plasma. The classical Spitzer-Harm distortion of the electron distribution function consistent with the MHD dynamo electric field is found to give a better modeling of the pellet trajectory.

Journal Article↗
PubMed1992

Skeletal involvement as the initial disease manifestation in Hodgkin's disease: a review of 6 cases.

Initial signs of malignant lymphoma are rarely due to bone lesions. We reviewed 6 cases with early skeletal involvement, recently observed in the rheumatology and hematology departments. In 3 patients, magnetic resonance imaging (MRI) was added to traditional investigations, including radiography, radionuclide bone scan and computerized tomography. We stress the possibility of bone involvement in the clinical onset of malignant lymphoma and the usefulness of early bone assessment using MRI.

Adult↗
PubMed1990

Production of granulopoiesis-stimulating and -inhibiting activities by T cells associated with malignant cells in lymphomas.

The possible role of T lymphocytes in the formation of granulomatous reactions seen in certain malignant lymphoid tumours was investigated by measuring the granulopoietic colony-stimulating activity (CSA) and granulopoietic-inhibiting activity (IA) produced by stimulated T-lymphocytes isolated from peripheral blood, spleen and lymph nodes of patients and normal subjects. Lymph-node T-cells from patients with benign lymphoid hyperplasia, B-cell non-Hodgkin's lymphoma (B-NHL), and non-granulomatous Hodgkin's disease (HD) showed no CSA, but the cells produced IA of 40 +/- 23%, 40 +/- 24% and 50.5 +/- 22.5% respectively. The corresponding cells from patients with HD accompanied by granulomatous reactions produced CSA of 6.85 +/- 6.5 u/microliters and IA of 23.5 +/- 21%. The presence of a granulomatous reaction in malignant lymphoma was correlated with the stimulation of granulopoiesis in vitro by T lymphocytes associated with malignant cells. A correlation was demonstrated between neutrophilic and eosinophilic colonies obtained in vitro under the influence of CSA-producing T cells isolated from malignant lymphomas and the neutrophils and eosinophils present in the granuloma. These results showed that tumour-infiltrating T cells play a role in the presence of granulomatous reactions seen in lymphomas. Peripheral-blood T cells from healthy subjects, and from patients with B-NHL, or with HD unaccompanied by granulocytic reactions produced CSAs of, respectively, 5 +/- 0.5 u/microliter, 4.8 +/- 2.2 u/microliters and 5.3 +/- 0.4 u/microliters, and IAs of 45 +/- 18%. 50 +/- 5.5% and 50.5 +/- 7% respectively. The corresponding values for HD patients with granulocytic reactions were CSA. 17 +/- 15.5 u/microliters, and IA, 9.5 +/- 9%. No correlation was demonstrated between neutrophilic colonies obtained in vitro under the influence of HD blood T cells and neutrophils present in blood. Only one correlation was found: between the percentage of eosinophilic colonies and the number of blood eosinophils. HD blood T cells did not seem to explain completely granulocytic reactions seen in blood.

B-Lymphocytes↗
PubMed1990

Clinical and hematological improvement in a patient receiving danazol therapy for myelofibrosis with myeloid metaplasia.

We report the positive effect of danazol on clinical and hematological data in a patient with myelofibrosis and myeloid metaplasia. Severe cytopenia was corrected within 2 months and was maintained for an additional 2-month period. Myeloid metaplasia (lymph nodes and skin lesions) was greatly reduced. The patient experienced no side effects. We propose further trials to confirm the utility of this agent in this disease.

Danazol↗
PubMed1989

Limiting dilution analysis of the frequency of IL2 responsive T cells in lymph nodes involved by B-cell non-Hodgkin's lymphomas.

Total T lymphocytes separated from twelve lymph nodes involved by B-NHL were studied in limiting dilution experiments for their ability to proliferate in the presence of both R-IL2 used at a final concentration of 40 U/ml and irradiated autologous malignant B cells as feeders. The number of proliferating T-lymphocyte precursors (PTL-P) thus estimated was low in each case (mean: 1/4503; range, 1/200 to 1/11013). Once expanded, proliferation of the IL2 responsive T cells in the presence of autologous malignant B cells remained strictly dependent on the addition of exogenous IL2. Control cases consisted of T lymphocytes separated from peripheral blood of six healthy subjects and cultured in the presence of both R-IL2 (40 U/ml) and irradiated autologous total mononuclear cells as feeders; the mean frequency of PTL-P thus obtained (1/173; range, 1/49 to 1/457) was significantly higher than in malignant lymph nodes (p less than 0.01). These findings do not support the hypothesis that, in this series of patients, expansion of malignant B cells may lead to the activation and growth of T cells sensitized against the tumour.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1989

[Bone manifestations disclosing Hodgkin's disease and non-Hodgkin's malignant lymphoma. Analysis of 11 cases].

Bone localizations revealing Hodgkin's disease or non-Hodgkin's malignant lymphoma, are unusual. We are reporting 11 recent cases collected in rheumatology and haematology departments, including 4 where a comprehensive study of X-rays, scintigrams, axial tomograms and nuclear magnetic resonance imaging was performed. Review of the literature as well as our experience concerning the type of onset of the bone involvement, the clinical correlation, the imaging techniques, have led us to consider nuclear magnetic resonance as a decisive factor which should be offered at an early stage in the diagnostic approach.

Adult↗
PubMed1987

Splenectomy during chronic lymphocytic leukemia.

The combination of discontinuous high-dose chlorambucil therapy with splenectomy greatly increased the prognosis of aggressive forms of chronic lymphocytic leukemia (CLL). The median survival for 43 patients was 84 months from diagnosis and 48 months from splenectomy. For 15 stages O, according to Rai classification, obtained after splenectomy, duration ranged from 3 to 105 months. The median survival of a group of patients showing "nodular splenic infiltration" was 104 months and superior to that of a group of patients showing "diffuse splenic infiltration" (72 months). In four of 15 cases studied, the peripheral blood lymphocytic clone disappeared after splenectomy.

Adult↗
PubMed1987

Stimulation and inhibition of human granulopoiesis in vitro by normal and malignant T4- or T8-lymphocyte subpopulations.

We studied the role of total peripheral blood T-lymphocytes and separated subpopulations of OKT4+ and OKT8+ cells stimulated with concanavalin A in the regulation of human granulopoiesis. Unfractionated total T cells depleted of monocytes are capable of producing colony-stimulating activity (CSA) and colony-forming unit-clone (CFU-C) suppressor activity simultaneously. After positive selection of cell subsets using a fluorescence-activated cell sorter, these two activities were produced by OKT4+ lymphocytes, whereas OKT8+ cells displayed small amounts of CSA and were incapable of releasing suppressor activity. On the other hand, total human thymocytes and subsets defined by monoclonal antibodies Leu2a/Leu3a failed to express any detectable CSA or CFU-C suppressor activity. A total of 14 cases of phenotyped lymphoid malignancies were also studied: the results showed that the production of stimulating and/or inhibiting factors is neither clearly related to a discrete stage of differentiation nor to the OKT4/OKT8 phenotype. Moreover, three monoclonal T leukemias, OKT4+OKT8-, OKT4-OKT8-, and OKT4-OKT8+ have been able in each case to produce simultaneously CSA and CFU-C suppressor activity. Finally, these studies strongly suggest that the activities of T-lymphocytes involved in the regulation of granulopoiesis are not closely linked with OKT4/OKT8 phenotype.

Cell Adhesion↗
PubMed1985

[Cefmenoxime diffusion into cerebrospinal fluid during human purulent meningitis].

We treated 10 patients with bacterial meningitis by 150 mg/kg/day cefmenoxime divided into six intravenous infusions. CSF samples were taken one hour after an IV on the second and fifth days. CSF cefmenoxime determined by microbiologic assay was 8.3 mg/l on days 2 and 5. Every patient recovered without sequelae. In our opinion, these results may support use of cefmenoxime in bacterial meningitis.

Adult↗