References of "Greimers, Roland"
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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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See detailRelations entre la capacite de repeuplement thymique et de formation de lymphomes exprimee par des cellules preleucemiques radio-induites chez la Souris C57BL/Ka.
Rongy, A. M.; 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), 88-93

We have analyzed the repopulation of thymuses injected with preleukemic cells obtained at various interval after fractionated irradiation. Our results show that preleukemic cells can repopulate the thymus ... [more ▼]

We have analyzed the repopulation of thymuses injected with preleukemic cells obtained at various interval after fractionated irradiation. Our results show that preleukemic cells can repopulate the thymus transiently as normal thymocytes or they can proliferate in recipients. In all cases, preleukemic cells can give rise to donor lymphomas. [less ▲]

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See detailPhenotype of thymic lymphomas in the mouse.
Greimers, Roland ULg; Rongy, Anne Michel; Defresne, Marie-Paule ULg et al

in Leukemia Research (1986), 10(7), 777-82

The MP2 cell line was established from a murine leukemia virus-induced thymic lymphoma. Half of the cells were consistently L3T4 positive and less than 5% of the cells were Lyt-2 positive. Single cell ... [more ▼]

The MP2 cell line was established from a murine leukemia virus-induced thymic lymphoma. Half of the cells were consistently L3T4 positive and less than 5% of the cells were Lyt-2 positive. Single cell cloning on the basis of the presence or absence of Lyt-2 allowed the isolation of four clones with stable phenotypes: (1) Lyt-2-, L3T4-; (2) Lyt-2+, L3T4+; (3) Lyt-2-, L3T4+; (4) Lyt2+, L3T4-. These data are discussed in relation to tumour cell heterogeneity and to normal T-cell differentiation pathways. [less ▲]

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See detailEffects of marrow grafting on preleukemia cells and thymic nurse cells in C57BL/Ka mice after a leukemogenic split-dose irradiation.
Defresne, Marie-Paule ULg; Greimers, Roland ULg; Lenaerts, Patrick et al

in Journal of the National Cancer Institute (1986), 77(5), 1079-85

A split-dose regimen of whole-body irradiation (4 X 175 rad at weekly intervals) induced thymic lymphomas in C57BL/Ka mice after a latent period of 3-9 months. Meanwhile, preleukemia cells arose in the ... [more ▼]

A split-dose regimen of whole-body irradiation (4 X 175 rad at weekly intervals) induced thymic lymphomas in C57BL/Ka mice after a latent period of 3-9 months. Meanwhile, preleukemia cells arose in the thymus and bone marrow and persisted until the onset of lymphomas. Simultaneously, thymic lymphopoiesis was impaired; thymocyte numbers were subnormal and thymic nurse cells disappeared in a progressive but irreversible fashion. The depletion of these lymphoepithelial complexes, which are normally involved in the early steps of thymic lymphopoiesis, was related to altered prothymocyte activity in bone marrow and to damaged thymic microenvironment, perhaps as a consequence of the presence of preleukemia cells. The grafting of normal bone marrow cells after irradiation prevented the development of lymphomas. However, marrow reconstitution did not inhibit the induction of preleukemia cells. They disappeared from the thymus during the second part of the latent period. At the same time, thymic lymphopoiesis was restored; thymocytes and nurse cell numbers returned to normal as a consequence of the proliferation of grafted marrow-derived cells within the thymus. The results thus demonstrated an intimate relationship between preleukemia cells and an alteration of thymic lymphopoiesis, which particularly involved the nurse cell microenvironment. Some preleukemia cells in marrow-reconstituted, irradiated mice derived from the unirradiated marrow inoculate. Thus these cells acquired neoplastic potential through a factor present in the irradiated tissues. The nature of this indirect mechanism was briefly discussed. [less ▲]

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