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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nonproducer cells transformed by Kirsten sarcoma virus (KiSV) or Abelson murine leukemia virus (A-MuLV) were infected with N- or NB-tropic helper viruses to rescue the defective transforming virus. The titer of the transforming viruses was determined on NIH/3T3 fibroblast-like cells and cell-free filtrates of virus stock were inoculated into newborn Fv-1nn mice. Friend, Moloney, and Rauscher group of MuLV (FMR) pseudotypes of KiSV induced an erythroid leukemia efficiently, while an endogenous helper (N35-MuLV) pseudotype of KiSV did not. FMR pseudotypes of A-MuLV induced the Abelson lymphoid leukemia, while the N35-MuLV or a Kirsten leukemia virus (Ki-MuLV) pseudotype did not. Pseudotypes of A-MuLV were used to infect bone marrow cells of Fv-1nn mice in vitro. The FMR pseudotypes transformed bone marrow cells at 40-100-fold higher frequency than the N35-MuLV or Ki-MuLV pseudotypes. Mixing experiments demonstrated that the addition of an effective helper, such as M-MuLV did not enhance lymphoid transformation by ineffective A-MuLV (N35-MuLV). The A-MuLV genome is responsible for hematopoietic cell transformation because a nonproducer clone of lymphoid cells, free of helper virus, was isolated. The data indicates that the pseudotype of A-MuLV determines its ability to transform hematopoietic cells.
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PMID:Effect of pseudotype on Abelson virus and Kirsten sarcoma virus-induced leukemia. 20 44

A cell culture method has been developed in which spleen cells from Friend virus (FV) infected mice can be studied for virus production as well as erythroid differentiation. Primary spleen cell cultures from plethoric Balb/c mice were initiated at 24, 48 or 73 h after FV infection. These cells manifested a well-defined wave of heme synthesis at approximately 64, 48, or 23 h, respectively, of cell culture. Assays for spleen focus-forming virus (SFFV) and helper murine leukemia virus (MuLV-F) production in these cultures revealed that the peak rates of production of both viruses occurred at essentially the same time as the peaks of heme synthesis. The time at which the peaks of virus production and heme synthesis occurred in vitro was related to the time interval after infection (80-105 h) rather than the time at which the cells were placed in cell culture or the number of hours of cell culture. Medium change experiments suggested that the temporal relation between heme synthesis and virus production was an intrinsic feature of FVP infected cells in this in vitro system.
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PMID:Friend virus production and heme synthesis in primary mouse spleen cell cultures. 22 85

Chicken hematopoietic cells transformed in vitro and in vivo by seven strains of replication-defective avian leukemia viruses were assayed for the expression of six erythroid and five myeloid differentiation parameters, including differentiation-specific surface antigens as detected by newly developed antisera. The transformed cells were found to display three distinct phenotypes of differentiation. First, cells transformed by AEV resemble erythroblasts. They express heme, globin, carbonic anhydrase and erythrocyte cell surface antigen at low levels, and histone H5 and erythroblast cell surface antigen at high levels. Second, cells transformed by MC29, CMII, OK10 and MH2 viruses have macrophage-like properties. They strongly express Fc receptors, phagocytic capacity and macrophage cell surface antigen, but only weakly express myeloblast cell surface antigen and are negative for ATPase activity. Third, cells transformed by AMV and E26 viruses resemble myeloblasts in that they weakly express Fc receptors, phagocytic capacity and macrophage cell surface antigen but strongly express myeloblast cell surface antigen and ATPase activity. No difference was found between in vitro- and in vivo-transformed cells in the parameters tested. In light of recent genetic and biochemical evidence, we believe that these phenotypes reflect the action of three new types of viral-transforming genes, designated erb (erythroblast), mac (macrophage) and myb (myeloblast).
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PMID:Chicken hematopoietic cells transformed by seven strains of defective avian leukemia viruses display three distinct phenotypes of differentiation. 22 7

One hundred feline leukemia virus-positive cats with evidence of anemia were examined to determine characteristics of the anemia. The anemia was usually normochromic and normocytic, with low reticulocyte counts but with normal white blood cell and platelet counts. About one third of the cats had splenomegaly. The bone marrow was usually hypocellular or normally cellular, with an increased myeloid to erythroid ratio. A history of recent stress or infection in many cases indicated that the immunosuppressive effect of feline leukemia virus may have been involved. Supportive treatment with periodic blood transfusions was successful in prolonging survival. Corticosteroids and androgens may have been beneficial in some cases.
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PMID:Anemia associated with feline leukemia virus infection. 22 95

Bone marrow biopsies (244) performed with a Jamshidi needle were evaluated in 53 children with leukemia or aplastic anemia. Adequate specimens were obtained in 85%. Results of cellularity estimated by biopsy were compared to the cellularity of the aspirate versus volumetric determination of the myeloid-erythroid layer (buffy coat). A wide discrepancy was noted between marrow cellularity confirmed by biopsy versus the aspirate or buffy coat. The greatest variance was seen in the hypercellular or normocellular marrows, as estimated by biopsy, in which 39% were misinterpreted as moderately or severely hypocellular by aspirate. Volumetric measurement of buffy coat was least acceptable for estimating cellularity. Thus the biopsy has proved to be an important and reliable indicator of bone marrow cellularity.
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PMID:Bone marrow cellularity determination: comparison of the biopsy, aspirate, and buffy coat. 26 73

As an adjunct to conventional haematological and cytogenetic data, 22 cases of refractory cytopenia, and five with chronic myelomonocytic leukaemia, (CMML) were studied by bone marrow culture. Cultures from II such patients without an excess of marrow myeloblasts usually showed low, or undetectable, numbers of cells capable of giving rise to colonies of granulocytes and/or macrophages (CFUc) but near-normal numbers of cluster-forming cells and cells capable of forming erythroid colonies (CFUE). Those with similar blood pictures, but in whom the marrow contained a slight excess of myeloblasts (II cases), showed a more profound defect in growth patterns: low or undetectable numbers of CFUC, clusters and CFUE, results similar to those found in acute myeloblastic leukaemia, into which three of this group evolved. The patients with CMML gave comparatively normal CFUC, cluster and CFUE growth patterns.
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PMID:Bone marrow culture studies in refractory cytopenia and 'smouldering leukaemia'. 26 33

The pathophysiology of serially passaged myeloid leukemia of the RFM mouse was studied. The disease was characterized by progressive splenomegaly and infiltration of both marrow and spleen by myeloblasts. The animals became anemic and there was an associated erythroid hyperplasia in the spleen. Leukemic spleen cells obtained from animals early in the course of the leukemia were less malignant than those obtained from preterminal mice. The leukemia is most sensitive to alkylating agents but is also responsive to antimetabolites.
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PMID:Murine myeloid leukemia: I. Pathophysiology and drug sensitivity. 27 Oct 44

The density and size distribution of intramembranous particles (IMP) were determined for cells of the erythroid series. The number and size of IMP were measured on both fracture faces of erythroblastic leukemia cells, phenylhydrazine-induced reticulocytes and mature erythrocytes. We found that the number of IMP adhering to the protoplasmic fracture face of the plasma membrane increased with increasing maturation, while the number of particles adhering to the external fracture face did not correlate with maturational stage. In general, the mean size of particles adhering to both fracture faces decreased with increasing maturation after the erythroblastic stage. We interpret these results to mean that the IMP seen are derived from more than one macromolecular species and that they are distributed asymmetrically in the plasma membrane.
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PMID:Intramembranous particles in erythrocyte, reticulocyte and erythroblastic leukemic cells of the rat: a model system for erythrocyte maturation. 27 71

Neutrophil marrow cellularity was determined in seven patients with chronic granulocytic leukaemia (CGL). The size of the mitotic pool (promyelocytes and myelocytes) and the number of metamyelocytes and bands and of segmented neutrophils in the postmitotic pool were determined from measurements of neutrophil--erythroid ratios in marrow biopsy sections and ferrokinetic estimates of marrow normoblasts. A section mitotic index was calculated in each patient from the numbers of mitotic figures and mitotic pool cells counted on marrow sections. Basal values previously established in normal subjects for the mitotic pool, for metamyelocytes and bands, and for segmented neutrophils, were 2.11 +/- 0.36 x 10(9) cells/kg, 3.33 +/- 0.61 x 10(9) cells/kg, and 2.26 +/- 0.42 x 10(9) cells/kg, respectively (+/- 1 SD, n = 13). The basal section mitotic index was 0.07 +/- 0.01 (+/- 1 SD, n = 13). In the seven patients with CGL the mitotic pool comprised 3.71--25.70 x 10(9) cells/kg, metamyelocytes and bands 7.70--51.02 x 10(9) cells/kg, and segmented neutrophils 3.45--28.81 x 10(9) cells/kg. Mitotic indices ranged from 0.04 to 0.10. No relationship was found between marrow cellularity and blood neutrophil count. A negative correlation existed between mitotic pool cellularity and mitotic index (r = -0.76, n = 7 pairs). The results provide quantitative affirmation of neutrophil marrow hyperplasia and of increased neutrophil production by the marrow in CGL.
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PMID:A quantitative assessment of neutrophil marrow in seven patients with chronic granulocytic leukaemia. 27 55

Fetal liver cells of DBA/2 mice were infected with the anemic strain of Friend leukemia virus (FLV-A), which has no spleen focus-forming virus (SFFV) activity. The infected cells were grown in medium with or without erythropoietin. Transformed lines were isolated only from the infected cultures that had been treated with erythropoietin at the time of their initiation. The properties of three permanent cell lines in serial passage for over 2 years are described. Each has an aneuploid karyotype. Only the immature hematopoietic cells of the first line have metacentric chromosomes. They grow in suspension, as do the erythroleukemic lines derived from leukemic spleens of FLV-infected mice, and clone on agar. They produce tumors resembling reticulum cell sarcomas upon subcutaneous inoculation into syngeneic hosts. Stimulation of differentiation induced after treatment with dimethyl sulfoxide identifies the cells of the first line as being erythroid in origin. The two other lines are adherent and epithelioid in appearance. These lines may have originated from the nonhematopoietic cells present in fetal liver. No tumors were produced after the subcutaneous inoculation of 10(6) cells. All three lines synthesize virus. The virus is attenuated for leukemogenicity and has no SFFV activity. The transforming event appears to be specific, because fetal liver cells from C57BL/6 mice, which are resistant to the induction of leukemia by FLV, were not affected by the virus. Malignant transformation of erythroid cells by FLV-A in vitro confirms the in vivo findings that SFFV may not be a necessary prerequisite for the induction of erythroleukemia in susceptible hosts.
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PMID:Transformation of DBA/2 mouse fetal liver cells infected in vitro by the anemic strain of Friend leukemia virus. 28 21


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