References of "Humblet, Chantal"
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See detailThymus Involvement in Murine Acquired Immunodeficiency (Maids)
Colombi, Sonia; Deprez, Manuel ULg; de Leval, Laurence ULg et al

in Thymus (1994), 23(1), 27-37

Due to self-renewal of the peripheral pool of T-cells, adult thymectomy has normally little influence on immunocompetence. However, thymus might play a more important role in the setting of viral-induced ... [more ▼]

Due to self-renewal of the peripheral pool of T-cells, adult thymectomy has normally little influence on immunocompetence. However, thymus might play a more important role in the setting of viral-induced cytopathic effects on T-cells in the periphery. Therefore, thymus weight, cell numbers, and subset distribution were sequentially analysed after infection with RadLV-Rs, a viral mixture known to induce murine retrovirus induced immunodeficiency (MAIDS). Infection induced thymic atrophy (concerning organ weight as well as total cell number) which culminated seven weeks after inoculation. The atrophic process mostly reflected the depletion of double positive CD4+ CD8+ cells since their proportion sharply decreased around week 6. Single positive T-cells were less affected by the process. The proportion of B-cells progressively increased. Surprisingly, there was a strong correlation between the extent of atrophy and the frequency of B-cells in the thymus. Finally, an abnormal CD4+ T-cell subset lacking Thy-1 and previously described in the periphery also appeared in the thymus and its frequency was strongly correlated with the expansion of B-cells in this organ. [less ▲]

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See detailTnf-Alpha Is Involved in the Mechanism of Murine Thymic Lymphoma Prevention by Bone Marrow Grafting
Humblet, Chantal ULg; Deman, J.; Rongy, A. M. et al

in Advances in Experimental Medicine and Biology (1994), 355

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See detailAnalysis by in Situ Hybridization of Cytokine Mrnas Expression in Thymic Nurse Cells
Deman, J.; Humblet, Chantal ULg; Martin, M. T. et al

in Advances in Experimental Medicine and Biology (1994), 355

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See detailTnf-Alpha and Radiation-Induced Thymic Lymphomas
Boniver, Jacques ULg; Humblet, Chantal ULg; Delvenne, Philippe ULg et al

in Leukemia : Official Journal of the Leukemia Society of America, Leukemia Research Fund, U.K (1992), 6(Suppl 3), 83-84

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See detailAnalysis by in Situ Hybridization of Cells Expressing Mrna for Tumor-Necrosis Factor in the Developing Thymus of Mice
Deman, Johanne; Martin, M arie Thérèse; Delvenne, Philippe ULg et al

in Developmental Immunology (1992), 2(2), 103-9

We have used in situ hybridization to investigate the expression of TNF-alpha genes by thymic cells during fetal development in mice. In 14-day-old fetal thymuses, very scarce cells produce TNF-alpha mRNA ... [more ▼]

We have used in situ hybridization to investigate the expression of TNF-alpha genes by thymic cells during fetal development in mice. In 14-day-old fetal thymuses, very scarce cells produce TNF-alpha mRNA. A second phase of cytokine gene expression starts on day 16. The density of positive cells progressively increases up to day 20. Thymuses at 15 days of gestation and after birth do not express detectable cytokine mRNA. In an attempt to identify the nature of the TNF-alpha mRNA-producing cells, acid phosphatase activity, which is characteristic of the macrophage lineage, was studied in the same thymuses. Acid phosphatase-positive cells only appear on day 15. Their frequency increases up to birth. However, no correlation can be established between acid phosphatase--and TNF alpha mRNA--positive cells. The results indicate that a small subset of thymic cells is responsible for TNF-alpha mRNA production during ontogeny: These cells are not yet identified. The possible role of TNF-alpha in thymic ontogeny is discussed. [less ▲]

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See detailOntogeny of T-Cell Surface Molecules and Receptors in the Thymus
Defresne, Marie-Paule ULg; Humblet, Chantal ULg; Deman, J. et al

in Progress in Histochemistry and Cytochemistry (1992), 26(1-4), 194-200

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See detailAbnormal Thymocyte Subpopulations in Split Dose Irradiated C57bl/Ka Mice before the Onset of Lymphomas. Effects of Bone Marrow Grafting
Rongy, A. M.; Humblet, Chantal ULg; Lelievre, P. et al

in Thymus (1990), 16(1), 7-27

Fractionated whole-body X irradiation (4 x 1.75 Gy at weekly intervals) induces a high percentage of thymic lymphomas in C57BL/Ka mice. The present work reports the phenotypic alterations of thymocyte ... [more ▼]

Fractionated whole-body X irradiation (4 x 1.75 Gy at weekly intervals) induces a high percentage of thymic lymphomas in C57BL/Ka mice. The present work reports the phenotypic alterations of thymocyte subpopulations during the preleukemic period: there were a decrease of CD4+ CD8+ cells and an increase of CD4- CD8- and CD4- CD8+ cells. Marrow grafting early after irradiation that prevents lymphoma development restores the thymocyte subpopulations. In many instances, transplantation of 'preleukemic thymocyte inoculate' gives rise to an active and long lasting repopulation of recipient thymuses. However in all cases, donor lymphomas can develop after inoculation of 'preleukemic thymocyte inoculate'. [less ▲]

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See detailCellular Events in Radiation-Induced Lymphomagenesis
Boniver, Jacques ULg; Humblet, Chantal ULg; Rongy, A. M. et al

in International Journal of Radiation Biology (1990), 57(4), 693-8

Fractionated whole-body irradiation induces thymic lymphomas in most of treated C57Bl/Ka mice. The cellular events occurring during the latency period consist of the emergence of preleukaemic cells and of ... [more ▼]

Fractionated whole-body irradiation induces thymic lymphomas in most of treated C57Bl/Ka mice. The cellular events occurring during the latency period consist of the emergence of preleukaemic cells and of marked alterations to the T-cell lineage and the microenvironment within the thymus. The proportions of the various thymocyte subsets are modified, suggesting a blockage in the normal differentiation process. Thymic epithelial cells are functionally modified, leading to decreased interactions with immature thymocytes. Interestingly, bone marrow grafting early after irradiation, which inhibits the development of lymphomas, induces the disappearance of preleukaemic cells from the thymus, whereas thymocyte subpopulations and thymic epithelium are restored. Interferon gamma and tumor necrosis factor alpha also prevent the onset of lymphomas. Studies on the effect of bone marrow transplantation and cytokine inoculation in split-dose irradiated mice should allow characterization of the factors that modulate the progression of preleukaemic cells towards the neoplastic state. [less ▲]

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See detailEffect of Interferon-Gamma and Tumor Necrosis Factor-Alpha on Lymphoepithelial Interactions within Thymic Nurse Cells
Defresne, Marie-Paule ULg; Humblet, Chantal ULg; Rongy, A. M. et al

in European Journal of Immunology (1990), 20(2), 429-32

Isolated thymic nurse cells (TNC) represent a specialized microenvironment in vivo where thymocytes interact specifically with subcapsular epithelial cells. They are thought to play a critical role in the ... [more ▼]

Isolated thymic nurse cells (TNC) represent a specialized microenvironment in vivo where thymocytes interact specifically with subcapsular epithelial cells. They are thought to play a critical role in the process of T cell differentiation. We demonstrate that recombinant murine interferon-gamma and recombinant human tumor necrosis factor-alpha can act on these interactions: they stimulate TNC-derived epithelial cells to establish interactions with thymocytes in vitro and to form new lymphoepithelial complexes. This phenomenon is partially inhibited by anti-Ia monoclonal antibodies. Implications of these findings for normal intrathymic differentiation are discussed. [less ▲]

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See detailCellular Aspects of the Pathogenesis of Radiation--Induced Thymic Lymphomas in C57 Bl Mice (Review)
Boniver, Jacques ULg; Humblet, Chantal ULg; Rongy, A. M. et al

in In Vivo (Athens, Greece) (1990), 4(1, Jan-Feb), 41-3

Radiation-induced thymic lymphomas in C57Bl/Ka mice are interesting models for studying the successive steps of carcinogenesis. Irradiation initiates "preleukemic" cells, which are promoted to become ... [more ▼]

Radiation-induced thymic lymphomas in C57Bl/Ka mice are interesting models for studying the successive steps of carcinogenesis. Irradiation initiates "preleukemic" cells, which are promoted to become neoplastic. Studies in mice in which lymphoma development is inhibited by a bone marrow transplantation after irradiation suggest that radiation--induced alterations to the T cell lineage, and particularly to thymic microenvironment, are critical for the promotion of preleukemic cells. It is proposed that the lack of physiological differentiation signals within the thymus, as a result of irradiation, allows these cells to escape the normal controls of thymocyte production and pushes them towards neoplastic transformation. A disturbance in the production of cytokines may be involved, since exogenous cytokines, such as Interferon gamma or Tumor Necrosis Factor a, can inhibit radiation-induced lymphomagenesis, reproducing the effects of bone marrow transplantation. The model is thus suitable for studying the mechanisms of carcinogenesis and designing biological manipulation devoted to cancer prevention in individuals who have been exposed to oncogenic agents. [less ▲]

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See detailFurther Studies on the Mechanism of Radiation Induced Thymic Lymphoma Prevention by Bone Marrow Transplantation in C57bl Mice
Humblet, Chantal ULg; Defresne, Marie-Paule ULg; Greimers, Roland ULg et al

in Leukemia : Official Journal of the Leukemia Society of America, Leukemia Research Fund, U.K (1989), 3(11), 813-8

Whole body fractionated irradiation induces thymic lymphomas in C57BL/Ka mice after a latent period during which intrathymic lymphopoiesis is modified; thymocyte numbers are subnormal and the epithelial ... [more ▼]

Whole body fractionated irradiation induces thymic lymphomas in C57BL/Ka mice after a latent period during which intrathymic lymphopoiesis is modified; thymocyte numbers are subnormal and the epithelial component of thymic nurse cells (TNCs) is altered as estimated by the number of TNCs in vivo and by its ability to interact with immature thymocytes in vitro. A graft of normal bone marrow cells immediately after the last irradiation prevents the development of lymphomas; but when such a graft is performed 1 month later, it does not inhibit the emergence of tumors. In both cases the grafted precursors home and repopulate the thymus. However, the delayed graft does not exert any effect upon the altered epithelial component of TNCs, whereas the early one restores the numbers of TNCs and the function of their epithelial component. The results thus demonstrate that lymphoid thymic repopulation by a bone marrow graft is not sufficient to prevent the development of lymphomas and that there is an intimate relationship between tumor development and alterations of nurse cells microenvironment. [less ▲]

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See detailTumor Necrosis Factor and Interferon Gamma Inhibit the Development of Radiation-Induced Thymic Lymphomas in C57bl/Ka Mice
Boniver, Jacques ULg; Humblet, Chantal ULg; Defresne, Marie-Paule ULg

in Leukemia : Official Journal of the Leukemia Society of America, Leukemia Research Fund, U.K (1989), 3(8), 611-3

Recombinant tumor necrosis factor and/or gamma-interferon were injected into C57BL/Ka mice after completion of a whole body split dose irradiation, which usually induces thymic lymphomas in more than 90 ... [more ▼]

Recombinant tumor necrosis factor and/or gamma-interferon were injected into C57BL/Ka mice after completion of a whole body split dose irradiation, which usually induces thymic lymphomas in more than 90% of the animals. The survival and the incidence of thymic lymphomas were significantly reduced in the cytokine-injected irradiated mice. The protective effect was similar to that obtained by grafting normal bone marrow cells after irradiation. The mechanisms of lymphoma inhibition by TNF or IFN-gamma are discussed. [less ▲]

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See detailControl of Lymphoepithelial Interactions within Thymic Nurse Cells by Gamma-Interferon and Tumor Necrosis Factor Alpha. Possible Role in the Modulation of Intrathymic Education?
Defresne, Marie-Paule ULg; Humblet, Chantal ULg; Rongy, A. M. et al

in Thymus (1989), 13(3-4), 201-4

The role of cytokines in the process of intrathymic differentiation is not yet clearly established. The results presented in this paper demonstrate that interferon-gamma and tumor necrosis factor-alpha ... [more ▼]

The role of cytokines in the process of intrathymic differentiation is not yet clearly established. The results presented in this paper demonstrate that interferon-gamma and tumor necrosis factor-alpha regulate 'in vivo' and 'in vitro' the interactions between epithelial cells and thymocytes within thymic nurse cells. The mechanism of action of these cytokines and their possible physiologic role 'in vivo' are discussed. [less ▲]

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See detailThymus Homing and Reconstitution in Split Dose Irradiated Preleukemic Mice
Defresne, Marie-Paule ULg; Humblet, Chantal ULg; Greimers, Roland ULg et al

in Advances in Experimental Medicine and Biology (1988), 237

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See detailEtude cytofluorimétrique de la ploidie dans le thymus préleucémique chez la Souris C57B1/Ka soumise a une irradiation fractionnée
Greimers, Roland ULg; Defresne, Marie-Paule ULg; Rongy, A. M. et al

in Comptes Rendus des Séances de la Société de Biologie et de ses Filiales (1987), 181(4), 420-5

The ploidy of the thymus was studied in C57B1/Ka mice irradiated with 4 weekly X-Ray doses of 1.75 Gy. The determination of nuclear DNA content was performed by flow cytometry of intact thymocytes labeled ... [more ▼]

The ploidy of the thymus was studied in C57B1/Ka mice irradiated with 4 weekly X-Ray doses of 1.75 Gy. The determination of nuclear DNA content was performed by flow cytometry of intact thymocytes labeled with propidium iodide in presence of a mixture of chicken and rainbow trout red blood cells as internal reference standards. The method has been tested by detecting the sex difference in DNA content of G0/G1 of normal thymic mouse cells. The mean value was 2.9% higher in female mice. The thymus of almost 60% of irradiated male mice present a slight hypoploidy of 2.6% one month after the last irradiation. [less ▲]

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See detailMigration des cellules médullaires vers le thymus chez les souris C57BL/Ka soumises a une irradiation fractionnée
Humblet, Chantal ULg; Defresne, Marie-Paule ULg; Greimers, Roland ULg et al

in Comptes Rendus des Séances de la Société de Biologie et de ses Filiales (1987), 181(4), 426-31

Fractionated whole body X-irradiation (4 X 1.75 Gy at weekly intervals) induces a high percentage of thymic lymphomas in C57BL/Ka mice. These tumors develop after a long latency period during which the ... [more ▼]

Fractionated whole body X-irradiation (4 X 1.75 Gy at weekly intervals) induces a high percentage of thymic lymphomas in C57BL/Ka mice. These tumors develop after a long latency period during which the thymic lymphopoiesis is deeply altered. In the present work, we test wether those modifications are due to lack of prothymocyte homing to preleukemic thymuses. Our results show that the preleukemic state of the thymus don't prevent the homing of normal marrow precursors grafted immediately after an irradiation of 4 Gy. Thus the alterations of thymic lymphopoiesis observed after a leukemogenic irradiation are not due to a modification in the thymus receptivity to thymocyte precursors. [less ▲]

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See detailInteractions de cellules preleucemiques radio-induites et de greffe de moelle chez la Souris C57BL/Ka.
Humblet, Chantal ULg; Defresne, Marie-Paule ULg; Greimers, Roland ULg et al

in Comptes Rendus des Séances de la Société de Biologie et de ses Filiales (1987), 181(1), 82-7

The repopulation of thymus inoculated with radiation-induced preleukemia cells was studied in 400 R irradiated mice grafted with normal bone marrow cells. These marrow cells gave rise to an actively ... [more ▼]

The repopulation of thymus inoculated with radiation-induced preleukemia cells was studied in 400 R irradiated mice grafted with normal bone marrow cells. These marrow cells gave rise to an actively regenerating thymic progeny, as well as in 400 R treated mice receiving only a bone marrow graft. Moreover, the marrow graft did not prevent the progression of inoculated preleukemic cells towards lymphoma growth. [less ▲]

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