References of "Greimers, Roland"
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See detailFlow cytometry in prostate cancer: Histological and clinical correlation
de Leval, Laurence ULg; Waltregny, David ULg; Greimers, Roland ULg et al

in Acta Urologica Belgica (1994), 62(1), 37-43

DNA histograms were obtained by flow cytometry for 39 human prostate carcinomas (27 total prostatectomy specimens, 5 biopsies and 7 transuretral resections). The study was performed on formalin-fixed and ... [more ▼]

DNA histograms were obtained by flow cytometry for 39 human prostate carcinomas (27 total prostatectomy specimens, 5 biopsies and 7 transuretral resections). The study was performed on formalin-fixed and paraffin-embedded material. In this report, ploidy index did not seem to be a good marker of prognosis as no significant variation in ploidy was found neither among the different stages nor among the different Gleason categories. Proliferative index of the tumors seemed to be a more sensitive parameter; a significant relation was observed between proliferative index and stage of the tumor. The authors discuss these results under the light of previously reported observations. [less ▲]

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See detailCytofluorometric analysis of prostate cancer specimens: Histological and clinical correlations
de Leval, Laurence ULg; Waltregny, David ULg; Greimers, Roland ULg et al

in Acta Urologica Belgica (1994, January), 62

DNA histograms were oblained by flow cytometry for 39 human prostate carcinomas (27 total proslatectomy specimens, 5 biopsies and 7 transuretral resections). The study was performed on formalin-fixed and ... [more ▼]

DNA histograms were oblained by flow cytometry for 39 human prostate carcinomas (27 total proslatectomy specimens, 5 biopsies and 7 transuretral resections). The study was performed on formalin-fixed and paraffin-embedded. material. In this report, ploidy index did not seem to be a good marker of prognosis as no significant variation in ploidy was found neither among the different stages nor among the different Gleason categories. Proliferative index of the tumors seemed to be a more sensitive parameter; a significant relation was observed between proliferative index and stage of the tumor. The authors discuss these results under the light of previously reported observations. [less ▲]

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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 detailMadin Darby Bovine Kidney Cell Synchronization by Lovastatin: Application to Bovine Herpesvirus-1 Gene Expression
Vanderplasschen, Alain ULg; Hanon, E.; Benarafa, C. et al

in Veterinary Research (1994), 25(6), 555-67

The number of investigations involving cell proliferation has increased rapidly in the last years. One of the major difficulties in studying cell-cycle-related events is obtaining highly synchronous cell ... [more ▼]

The number of investigations involving cell proliferation has increased rapidly in the last years. One of the major difficulties in studying cell-cycle-related events is obtaining highly synchronous cell populations without metabolic imbalance. This study demonstrates that the Madin Darby bovine kidney (MDBK) cells, a commonly used cell line in veterinary research, can be effectively synchronized using lovastatin (Lov), a drug used to treat hypercholesteremia in humans. This was demonstrated by the following results: (i) Lov inhibits cell proliferation in a dose-dependent manner; (ii) Lov synchronizes MDBK cells mainly in the G1 and secondarily in the G2+M cell-cycle phases; (iii) the cytostatic effect of Lov can be specifically inhibited by addition of mevalonate (Mev) (Lov inhibits the synthesis of Mev); (iv) removal of Lov from G1-arrested cultures, followed by addition of Mev, resulted in the synchronous recovery of DNA synthesis; and (v) 5-bromo2'-deoxyuridine incorporation experiments revealed that MDBK cells synchronization by Lov can be followed for at least 3 cycles after removal of Lov and addition of Mev. Furthermore, as an application of investigations based on the availability of synchronized MDBK, we showed that bovine herpesvirus-1 gene expression is independent on the cell cycle. [less ▲]

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See detailPopulation dynamics of CD4+ T cells lacking Thy-1 in murine retrovirus-induced immunodeficiency syndrome (MAIDS).
Moutschen, Michel ULg; Colombi, S.; Deprez, Manuel ULg et al

in Scandinavian Journal of Immunology (1994), 39(2), 216-24

Increased numbers of CD4+ Thy-1- cells have been described in the spleen (SP) of mice with retrovirus-induced immunodeficiency (MAIDS). Since this phenotypic abnormality might have considerable functional ... [more ▼]

Increased numbers of CD4+ Thy-1- cells have been described in the spleen (SP) of mice with retrovirus-induced immunodeficiency (MAIDS). Since this phenotypic abnormality might have considerable functional importance, the expansion of the CD4+ Thy-1- subset in MAIDS was characterized further. CD4+ Thy-1- and Thy-1+ T-cells from infected mice expressed similar densities of CD3 and TCR alpha/beta. In contrast, the Thy-1- subset was uniformly CD44hi, even early in the disease when part of Thy-1+ cells were still CD44lo. The emergence of CD4+ Thy-1- cells occurred first in SP and lymph nodes and was observed later in thymus. The important fraction of CD4+ cells lacking Thy-1 normally present in Peyer's patches was only weakly modified. Despite the major expansion of the CD4+ Thy-1- phenotype, the proliferating fraction was not higher in this subset than in CD4+ Thy-1+ cells from infected mice. Persistence after hydroxyurea administration was identical in both subsets, indicating similar mean cell lifespans. Taken together, these results show that the major expansion of CD4+ Thy-1- T-cells in MAIDS is not ascribable solely to increased proliferation within this subset. Phenotypic analysis suggests that CD4+ Thy-1- cells result from the differentiation of Thy-1+ cells induced by activation signals related to retroviral infection. [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 detailLymphocyte Lifespan in Murine Retrovirus-Induced Immunodeficiency
Moutschen, Michel ULg; Colombi, S.; Deprez, Manuel ULg et al

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

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See detailMixed Phenotype Murine Leukemias
Defresne, Marie-Paule ULg; Borremans, B.; Verhofstede, C. et al

in Leukemia : Official Journal of the Leukemia Society of America, Leukemia Research Fund, U.K (1993), 7(8), 1253-60

Cell lines were derived from eight individual leukemias induced by X-rays in NFS mice. First typed as null cells (surface immunoglobulin negative, Thy-1 negative), they turned out to have a mixed ... [more ▼]

Cell lines were derived from eight individual leukemias induced by X-rays in NFS mice. First typed as null cells (surface immunoglobulin negative, Thy-1 negative), they turned out to have a mixed phenotype with myeloid cytochemical markers, pre-B surface antigens and molecular markers of pro-B lymphocytes. They represent murine models for mixed phenotype (pro-pre-B-myeloid) leukemias. [less ▲]

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See detailEfficient Immunoselection of Cytolytic Effectors with a Magnetic Cell Sorter
Jacobs, Nathalie ULg; Moutschen, Michel P; Boniver, Jacques ULg et al

in Research in Immunology (1993), 144(2), 141-50

This paper describes a rapid and efficient method for the sorting of in vitro activated cytolytic effectors cells. For cytotoxic assays, a large number of cells with conserved function must be rapidly ... [more ▼]

This paper describes a rapid and efficient method for the sorting of in vitro activated cytolytic effectors cells. For cytotoxic assays, a large number of cells with conserved function must be rapidly obtained. Immunomagnetic sorting was chosen because it is faster than flow cytometry sorting. The MACS system requires the use of paramagnetic beads of small diameter (100-150 nm), reputed to interfere minimally with cell function. In order to generate the cytolytic effectors, peripheral blood lymphocytes were cultivated in the presence of interleukin-2 (50 U/ml) and anti-CD3 monoclonal antibody (BMA030, 100 ng/ml) for 4 days. Cell separation was based on the membrane expression of the CD3 complex. The purity obtained for positive (CD3+) cell sorting with the MACS was higher than 95%. The purity of negative (CD3-) cell fraction was more variable, but further purification by flow cytometry rapidly yielded purity higher than 95%. Cytotoxic assays were performed against four target cell lines (K562, Daudi, HL60 and U937) and proliferation assays showed that both negatively and positively selected populations had conserved their function acquired during culture in the presence of anti-CD3 mAb and IL2. [less ▲]

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See detailStrychnopentamine, a Potential Anticancer Agent
Quetin-Leclercq, J.; Bouzahzah, B.; Pons, A. et al

in Planta Medica (1993), 59(1), 59-62

We analysed the effects of strychnopentamine, an alkaloid isolated from Strychnos usambarensis, on an Ehrlich ascites tumor growing in the mouse after inoculation. Four subcutaneous injections of 1.5 mg ... [more ▼]

We analysed the effects of strychnopentamine, an alkaloid isolated from Strychnos usambarensis, on an Ehrlich ascites tumor growing in the mouse after inoculation. Four subcutaneous injections of 1.5 mg strychnopentamine (1 per day) induce a significant decrease of the number of tumor cells and a significant increase of the survival of the treated mice. Observed side effects are partial haemolysis and some liver damage. [less ▲]

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See detailCell Surface Receptors in Lymphoid Cells: From Cytochemistry to Molecular Biology and from a Phenotype to a Function
Boniver, Jacques ULg; Courtoy, R.; Schaaf-Lafontaine, Nicole ULg et al

in Progress in Histochemistry and Cytochemistry (1992), 26(1-4), 169-81

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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 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 detailInduction of Thymocyte Proliferation by Supernatants from a Mouse Thymic Epithelial Cell Line
Villa-Verde, Dea; Defresne, Marie-Paule ULg; Greimers, Roland ULg et al

in Cellular Immunology (1991), 136(1), 113-21

The thymic stroma plays a critical role in the generation of T lymphocytes by direct cell-to-cell contacts as well as by secreting growth factors or hormones. The thymic epithelial cells, responsible for ... [more ▼]

The thymic stroma plays a critical role in the generation of T lymphocytes by direct cell-to-cell contacts as well as by secreting growth factors or hormones. The thymic epithelial cells, responsible for thymic hormone secretion, include morphologically and antigenically distinct subpopulations that may exert different roles in thymocyte maturation. The recent development of thymic epithelial cell lines provided an interesting model for studying thymic epithelial influences on T cell differentiation. Treating mouse thymocytes by supernatants from one of TEC line (IT-76M1), we observed an induction of thymocyte proliferation and an increase in the percentages of CD4-/CD8- thymocytes. This proliferation was largely inhibited when thymocytes were incubated with IT-76M1 supernatants together with an anti-thymulin monoclonal antibody, but could be enhanced by pretreating growing epithelial cells by triiodothyronine. We suggest that among the target cells for thymulin within the thymus, some putative precursors of early phenotype might be included. [less ▲]

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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 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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