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J Samarut

Publications and source records attributed to J Samarut.

At least 109 records · Page 6Linked to original sources
PubMed1983

Characterization of the hemopoietic target cells for the avian leukemia virus E26.

The dual leukemogenic response, involving both the erythroid and myeloid hemopoietic systems in chickens infected with E26 virus, has previously been described (C. Moscovici, J. Samarut, L. Gazzolo, and M. G. Moscovici, 1981. Virology 113, 765-768; K. Radke, H. Beug, S. Kornfeld, and T. Graf, 1982. Cell 31, 643-653). Similarly, the in vitro response of the two lineages resulted in the concomitant transformation and proliferation of erythroblast and myeloblast leukemic cells. The present study, using embryonic tissues at very early stages of development, was valuable in implying that E26 target cells are recruited among uncommitted erythroid-myeloid stem cells as well as myeloid- or erythroid-committed progenitor cells. Therefore, E26 may be the first avian retrovirus capable of interacting with uncommitted hemopoietic precursor cells.

Animals↗
PubMed1982

Target cells infected by avian erythroblastosis virus differentiate and become transformed.

Transformation in vitro of bone marrow cells by avian erythroblastosis virus (AEV) gives rise to rapidly growing cells of erythroid nature. Target cells of neoplastic transformation by AEV are recruited among the early progenitors of the erythroid lineage, the burst-forming units-erythroid (BFU-E). They express a brain-related antigen at a high level and an immature antigen at a low level. We show that AEV-transformed cells express low levels of the brain antigen and high levels of the immature antigen. Their response to specific factors regulating the erythroid differentiation indicates that they are very sensitive to erythropoietin. Furthermore, cells transformed by a temperature-sensitive mutant of AEV differentiate into hemoglobin-synthesizing cells 4 days after being shifted to the nonpermissive temperature. All these properties are similar to those of late progenitors of the erythroid lineage, the colony-forming units-erythroid (CFU-E). These results indicate that the AEV-transformed cells are blocked in their differentiation at the CFU-E stage.

Alpharetrovirus↗
PubMed1980

In vitro development of CFU-E and BFU-E in cultures of embryonic and post-embryonic chicken hematopoietic cells.

A culture method is proposed for the in vitro development of chicken erythrocytic progenitors. When grown with avian erythropoietin, Colony Forming Unit Erythrocytic (CFU-E) and Burst Forming Unit-Erythrocytic (BFU-E) give rise respectively to erythrocytic colonies and bursts within 3 and 6 days. BFU-E development is greatly enhanced by pokeweed-mitogen-spleen-cell conditioned medium and requires higher erythropoietin concentrations than for CFU-E. An antigen specific to immature red cells can be detected on CFU-E but not on BFU-E, showing that both progenitors represent distinct entities. BFU-E and CFU-E are found in embryonic marrow and yolk sac. In the young blastoderm BFU-E becomes detectable at the primitive streak stage.

Animals↗
PubMed1980

Early precursors in the erythroid lineage are the specific target cells of avian erythroblastosis virus in vitro.

In chickens the erythroid differentiation proceeds from stem cells to erythrocytes through several intermediate steps which have been identified in vivo and in vitro. To determine whether Avian erythroblastosis virus (AEV) is able to transform in vitro either one or several types of these precursors, bone marrow cells were separated by physical and immunological methods. It was found that the target cells which could be transformed in vitro by AEV were cells of light density (1.060-1.065 g/cm3), having a modal sedimentation velocity at unit gravity between 4.0 and 6.0 mm/hr, expressing an immature antigen at a low level and a brain-related antigen at a high level. These results indicated that the target cells of neoplastic transformation by AEV were early erythroid precursors, since these precursors shared the same physical and immunological properties with AEV target cells.

Alpharetrovirus↗
PubMed1979

Response of hemopoietic cells to avian acute leukemia viruses: effects on the differentiation of the target cells.

Chicken bone marrow cells were infected with three avian acute leukemia viruses (ALV)--avian myeloblastosis virus (AMV), myelocytomatosis virus strain MC29 and Mill Hill 2 virus (MH2)--and then cultured in agar in the presence of conditioned medium. Under these conditions, it was found that very few cells served as target cells for these three viruses. Density gradient separation showed that ALV target cells were found primarily in the light density fractions and might be represented by cells committed to the mononuclear phagocyte pathway. Separation of bone marrow cells on the basis of their sedimentation velocity at unit gravity suggested that MC29 and AMV did not share the same target cells. In addition, the analysis of surface receptors and functional markers characteristic of macrophages (Fc and complement receptors, phagocytosis and immune phagocytosis) indicated that the ALV-transformed cells were blocked during their differentiation. These results indicate that the transforming ability of ALV interferes with the differentiation of their target cells.

Avian Leukosis Virus↗
PubMed1979

Production of fetal antigen-bearing erythrocytes in irradiated adult mice grafted with fetal liver hematopoietic cells.

The production of erythrocytes bearing an "immature" antigen (Im+ cells) and a "fetal" antigen (Ft+ cells) has been studied in irradiated adult mice grafted either with fetal liver or adult bone marrow cells. The Im+ cells reach a peak 8-11 days after grafting. Ft+ cells are detected only after graft of fetal liver cells; the younger the liver, the greater the number. Since Ft+ cells are rapidly and briefly produced, they could be the progeny of erythroid-committed precursors, which are particularly numerous among fetal liver cells. Environmental factors directing the erythropoietic differentiation towards Ft+ erythrocytes in fetuses or Ft- erythrocytes in adults are proposed.

Aging↗
PubMed1979

Production of erythropoietic colony-forming units and erythrocytes during chick embryo development: an attempt at modelization of chick embryo erythropoiesis.

The enumeration of erythropoietic colony-forming cells in vitro has allowed us to complete previous data on changes in the various erythroid cell populations during chick embryo-genesis. Erythrocytic colony-forming units in culture (CFU-cE) which are sensitive to avian erythropoietin appear in the blastoderm as soon as the 24th hour of development. They represent most likely precursors of the megalocytic erythropoiesis, and do not seem to derive from stem cells common with normocytic erythropoiesis. Data concerning vitelline normocytic erythropoiesis were analysed in a kinetic model based on stochastic change of the stem cells. From this model it appears that 17-20 cell divisions are required for differentiation of erythrocytes from stem cells.

Animals↗
PubMed1976

Properties and development of erythropoietic stem cells in the chick embryo.

1. When injected into irradiated chickens, haemopoietic stem cells give rise to well-defined erythrocytic colonies in the host marrow. Such stem cells (CFU-M = Colony Forming Unit in Marrow) have been found in different tissue of the chicke embryo (yolk sac, blood, marrow). Analysis of the properties of CFU-M reveals that they represent two classes of stem cells: pluripotent stem cells mainly in adult marrow and erythrocytic-committed stem cells present in yolk sac. 2. Yolk sac contains the main pool of CFU-M during the major part of embryonic life. In the blood of 6-day-old embryo, there are three or four times more CFU-Ms than in the yolk sac; they are no longer detected in the blood after the 16th day of incubation. During development of the marrow, stem cells are actively differentiating and their total number remains the same from 16 days to hatching.

Age Factors↗
PubMed1975

[Differentiation of haemopoietic tissues from embryos and adults injected into irradiated chickens (author's transl)].

Irradiated chicken are injected with haemopoietic tissues from adult or 11-day-old embryos. Development of stem cells gives rise to well-defined erythrocytic colonies on the surface of the tibial marrow. Erythropoietic production appears to be similar from adult marrow and embryonic blood stem cells; production from injected vitelline stem cells seems to be between 3 and 4 times higher than that of adult marrow stem cells. Results are discussed on the basis of two hypotheses: -existence of an extramedullary erythropoietic site in the host after vitelline cells grafting; -development of vitelline stem cells in the host marrow with kinetic patterns different from those of grafted adult marrow or embryonic blood stem cells. Anyway, the 11-day-old embryo appears to contain at least two types of blood stem cells with distinctive properties. Developmental origin, relationship and future of these different stem cells remain to be analysed.

Animals↗
PubMedDate not supplied

Kinetics and biochemical properties of haemopoietic stem cells during chicken development.

Haemopoietic stem cells from donors of different ages (embryos, adults) have been grafted into irradiated hosts. Cell multiplication kinetics, foetal haemoglobin production, age-specific antigen production were examined during two weeks after grafting. The results obtained tend to show that the erythrocyte characteristics are, for a large part, already determined in a stem cell type endowed with a large proliferative capacity.

Age Factors↗