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Biomedical subjects

B Varet

Publications and source records attributed to B Varet.

At least 145 records · Page 8Linked to original sources
PubMed1981

Comparative effects of polycythemia-inducing Friend leukemia virus and Moloney leukemia virus on hematopoietic progenitors in murine long-term bone marrow cultures.

The specificity of murine leukemia virus-induced myelomonocytic phenotypic changes in long-term bone marrow culture have been examined by comparing the effects of polycythemia-inducing Friend leukemia virus (FVP) and Moloney murine leukemia virus (M-MuLV) known to have in vivo target cells in the erythroid and lymphoid lineage, respectively. Noninfected adn M-MuLV-infected cultures showed no modification in granulocyte macrophage colony-forming cell behavior and failed to generate cell line in WEHI-3-conditioned medium. In contrast, in FVP-infected cultures, granulocyte macrophage colony-forming cells became colony-stimulating factor independent, and the nonadherent cells gave rise to two cell lines in WEHI-3 conditioned medium with monocytic characteristics and no leukemogenic potential in vivo. These results confirm the ability of long-term bone marrow culture to unmask target cells for FVP within myelomonocytic progenitors, and the negative results in M-MuLV-infected cultures underline the specificity of the FVP-induced phenotypic changes. Despite a high level of virus production and the presence of T-cell precursors in the M-MuLV infected culture, T-cell transformation was not observed.

Animals↗
PubMed1981

[Acute neutropenia in adult severe bacterial infections. Six cases (author's transl)].

A transient neutropenia (duration : less than 48 hours) occurred in 6 patients with severe bacterial infections. The bone marrow myeloïd cellularity was high or normal; a maturation arrest of the myeloïd cells - at a variable stage - was present in each case, as well as circulating granulocyte precursors. Other causes of neutropenia were excluded. A general survey of the literature is made and the mechanisms of this bacterial neutropenia are considered : bone marrow failure seems mostly improbable ; the few previously reported cases, the experimental bacterial neutropenias, the peculiar, transient, evolution we observed, all favor a peripheral mechanism ; the bacterial infection seems to act by; two ways : in septicemia (especially during septic shock) by enhancing leucocyte margination along vascular walls ; in large septic foci (mostly pulmonary) by an important destruction of polymorphonuclear neutrophils. Such bacterial infections share a bad prognosis but the neutropenia itself needs no specific treatment.

Acute Disease↗
PubMed1981

Erythroid progenitors in polycythemia vera.

Recent data concerning in vitro studies of erythroid progenitors in polycythemia vera (PV) are reviewed. As shown by different laboratories, at least two populations of CFUE seem to coexist in the bone marrow of such patients: one exhibits normal in vitro behavior; the other, probably of clonal origin, is abnormally sensitive to erythropoietin. This abnormal population of CFUE is highly sensitive to trace amounts of erythropoietin and is probably responsible for the in vivo development of polycythemia despite a depressed level of erythropoietin. At the BFUE level, two populations also seem to coexist. However, the abnormal behavior of erythroid progenitors is probably not expressed at this early level of differentiation but only at the late CFUE level. This is in agreement with some of the data, which suggest that in the differentiation of erythroid progenitors into erythroblasts, erythropoietin is only needed at a level very close to CFUE.

Animals↗
PubMed1980

[Secretion of a granular colony-stimulating factor by an adherent layer of long-term hematopoietic bone marrow cultures in mice].

The presence of a CSF activity in long term bone marrow cultures in Mice was not described until now. Using a double layer agar technique directly on the adherent layers of the cultures, a strong CSF activity is detected in these adherent layers, before recharging the cultures at the third week, or when the cultures are not recharged. The role of this activity in long term myelopoiesis maintenance in vitro is discussed.

Animals↗
PubMed1980

[A case of alpha chain disease in an African negro (author's transl)].

A new case of alpha chain disease is described in an African negro (Zaïre). The initial diagnosis was lymphoma, diffuse immunoblastic type. serum protein electrophoresis exhibited a normal pattern but immunoelectrophoresis demonstrated alpha heavy chain without reactivity with anti light chains antisera. It seems to be the third case of alpha chain disease in a black patient.

Adult↗
PubMed1979

[Auto-immune hemolytic anemia associated with Kaposi's sarcoma. Report of a new case (author's transl)].

The association of Kaposi angiosarcomatosis and an auto-immune haemolytic anaemia is reported in a 69-year-old woman. The direct Coombs test was "igG complement" type positive. This is the 5th reported case and the 2nd in which haemolysis developed during an acute malignant exacerbation of the disease. The patient died less than 4 months following the diagnosis of Kaposi's sarcoma, after treatment with prednisone and chlorambucil. Lymphoid and immunological abnormalities are not rare during the course of Kaposi's sarcoma. The reasons are discussed briefly.

Aged↗
PubMed1979

[In vitro study of erythroblast precursors in Vasquez disease (polycythemia vera). Arguments in favor of a double population of erythroblastic stem cells in the bone marrow].

In vitro studies using the plasma clot culture system have been performed in order to compare the red cell pregenitors able to rise to erythrocytic colonies in 7 days (CFUE) in the bone marrow of polycythemia vera (PV), secondary polycythemias and normal subjects. In PV but never in normal individuals or secondary polycythemias, the bone marrow cells producing erythroid colonies without addition of erythropoietin were found. The erythropoietin dode response curves in PV is biphasic with a plateau up to a concentration of erythropoietin of 0.02-0.05 i.U./ml followed by a near normal response to erythropoietin at higher doses. Thus our results demonstrate that two populations of erythroid stem cells coexist in PV, one being abnormally sensitive to (or independant of) erythropoietin, the other normally responding to erythropoietin. After remission induced by P32 treatment, the abnormal population can disappear but the prognostic significance of this disappearance is uncertain. On the whole these results are in agreement with those of others laboratories using the plasma clot culture system. The reasons of the disagreement with the data published using the methylcellulose technic of culture are discussed.

Animals↗
PubMed1978

[Hemolytic anemia].

Explore the source record for details and available documents.

Anemia, Hemolytic↗
PubMed1978

[Demonstration of erythroblastic differentiation after 14 days in blood in vitro during Vaquez's disease without addition of erythropoietin].

Leucocytes of normal individuals and patients with polycythemia vera were isolated from the peripheral blood by Ficoll-Hipaque density gradient centrifugation and cultured in vitro suing the bovine plasma clot culture technique with a minor modification: the addition of fresh normal serum. After 14 days in the presence of sheep erythropoïetin (3U/ml) erythropoïetic bursts containing between 3 and 10 subcolonies were observed in normal and polycythemia vera cultures. Blood leucocytes of patients with polycythemia vera rise to these erythropoïetic bursts without addition of erythropoïetin to the culture. This behavior was never observed in the blood of normal individuals. These results indicate that in polycythemia vera commited erythroïd stem cells of high proliferative capacity closely resembling the murine erythroïd burst forming unit have an abnormal sensitivity to erythropoïetin as well as the immediate precursors of the proerythroblasts. The culture of these cells from the peripheral blood offers some practical advantages.

Cell Differentiation↗
PubMed1978

[In vitro study of erythroid precursors in Vaquez' disease (polycythemia vera). Evidence supporting 2 populations of erythroid stem cells in the bone marrow].

In vitro studies using the plasma clot culture system have been performed in order to compare the red cell pregenitors able to rise to erythrocytic colonies in 7 days (CFUE) in the bone marrow of polycythemia vera (PV), secondary polycythemias and normal subjects. In PV but never in normal individuals or secondary polycythemias, the bone marrow cells producing erythroid colonies without addition of erythropoietin were found. The erythropoietin dose response curves in PV is biphasic with a plateau up to a concentration of erythropoietin of 0.02--0.05 i.U./ml followed by a near normal response to erythropoietin at higher doses. Thus our results demonstrate that two populations of erythroid stem cells coexist in PV, one being abnormally sensitive to (or independent of) erythropoietin, the other normally responding to erythropoietin. After remission induced by P32 treatment, the abnormal population can disappear but the prognostic significance of this disappearance is uncertain. In the whole these results are in agreement with those of others laboratories using the plasma clot culture system. The reasons of the disagreement with the data published using the methylcellulose technic of culture are discussed.

Cell Differentiation↗
PubMed1978

[Aleukemic chloroma. review of literature and diagnostic problems: 1 case].

The authors report the case of a 30-year-old man with granulocytic sarcoma of the chest wall presenting as a swelling with axillary lymphadenopathy followed by pleuropericardial effusions. The myeloblastic nature of the tumor cells was confirmed on the adenogram by the detection of granulations, rare Auer bodies and myeloperoxydase activity. It was confirmed by the presence of numerous granulations by electron microscopy and by that of a chloracetate esterase activity detected using Leder's protocol (9) on sections of material mounted in paraffin wax after formol fixation. Four marrow biopsies form different sites were normal. The course was fatal in six months, despite multiple chemotherapy, with massive invasion of the thorax by the tumor without the presence of myeloblasts in the circulating blood. The autopsy confirmed the preponderance of thoracic involvement (greenish in colour) and the presence of diffuse marrow myeloblastosis. In the light of this case, the rare instances (of the order of 10) of aleukaemic chloroma recorded in the literature are reviewed, emphasising the difficulties of diagnosis of these tumours and the ways in which they may be overcome.

Adult↗