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Biomedical subjects

E A McCulloch

Publications and source records attributed to E A McCulloch.

At least 19 recordsLinked to original sources
PubMed1979

Acute myeloblastic leukemia considered as a clonal hemopathy.

Acute myeloblastic leukemia, like certain other hematologic disorders, originates in pluripotent stem cells. Two general biologic processes underlie development of the disease. Over long times, clonal progression leads from normal polyclonal hemopoiesis through clonal preleukemia to leukemia. Overt leukemia is characterized by the emergence of blast cell populations. Over shorter times, clonal expansion yields cellular diversity based upon randomizing events. The analysis indicates that that blast population is of crucial importance. Characteristics of a colony assay for blast cell progenitors are presented.

Clone Cells↗
PubMed1979

Self-renewal in culture of proliferative blast progenitor cells in acute myeloblastic leukemia.

We have proposed that colonies of cells with blastlike morphology growing in culture are derived from a blast subpopulation with high proliferative potential. To test whether or not these blast progenitors have the capacity for self-renewal, blast colonies grown from the peripheral blood of the 21 patients with acute myeloblastic leukemia were replated; secondary colonies were observed in 17 instances, and these were similar to primary colonies in size, morphology, and culture requirements. Great patient-to-patient variation was observed in the frequency of secondary colonies, but low secondary plating efficiency was significantly correlated with successful remission induction. We conclude that the blast progenitors detected in the assay have at least limited self-renewal capacity and that this capacity may, along with other risk factors, contribute to clinical outcome.

Adult↗
PubMed1979

Cytotoxicity of adriamycin and daunorubicin for normal and leukemia progenitor cells of man.

A colony assay available for a subpopulation of acute myeloblastic leukemia blasts with proliferative potential was used to measure adriamycin (adria) and daunorubicin (dauno) dose-response curves following brief exposure to either drug and washing. The dose-response curves were simple negative exponentials that might be characterized by D10 (dose required to reduce survival to 10%) values. The D10 values ranged from 0.47 to 20.8 microgram/ml for adria (8 patients) and from 0.06 to 0.34 microgram/ml for dauno (3 patients). Controls consisted of committed granulopoietic and T-lymphocyte progenitors. Four measurements of granulopoietic progenitors yielded D10 values from 2.5 to 11.5 mug/ml for adria and from 0.44 to 1.2 microgram/ml for dauno. T-lymphocyte precursors from 4 normal individuals were resistant. However, following incubation of normal leukocytes with phytohemagglutinin, DNA synthesis commenced in T-lymphocyte precursors for 3 additional normal controls, which was associated with an increased data sensitivity with D10 values ranging from 4.4 to 6.2 microgram/ml.

Animals↗
PubMed1979

Separation of blast cell and T-lymphocyte progenitors in the blood of patients with acute myeloblastic leukemia.

The peripheral blood of acute myeloblastic leukemia (AML) patients often contains large numbers of two distinct cell populations, both capable of forming colonies in culture under similar conditions. The first population consists of the precursors of blast cells and has specificity for AML; the second population consists of T-lymphocyte precursors, also found in normal blood. The two progenitor populations can be separated by exploiting the capacity of T-lymphocyte (but not blasts) progenitors to form rosettes with sheep erythrocytes (E rosettes). After E-rosette formation, T-lymphocyte precursors can be removed by centrifugation on Ficoll-Hypaque. Such separation has a number of consequences: (1) Blast progenitors can be detected where unseparated mononuclear preparations have yielded either no colonies or only T-lymphocyte colonies (20 of 21 patients). (2) The stimulator requirements of the blast progenitors change, indicating that cell-cell interactions may take place between blast and T-lymphocyte progenitors. (3) It is feasible to characterize blast and T-lymphocyte precursors independently, even though they may coexist in peripheral blood. This may be important if progenitor properties are attributes contributing to the variance in outcome in AML.

Cell Division↗
PubMed1978

Normal and leukemic hemopoiesis compared.

Using colony assays for human erythropoietic (BFU-E, CFU-E) and granulopoietic (CFU-C) progenitors, normal and leukemic myelopoietic differentiation were compared; similar patterns were found in both. However, the origin of blast cells characteristic of the disease could not be established indicating the need for a direct approach to these cells. A colony assay for blast cells in acute myeloblastic leukemia is described. Blast cell colony-formation is significantly correlated with blast cell number, and the colonies contain cells of blast like morphology without differentiation markers. It is proposed that this method, taken in conjunction with results from assays of myelopoiesis and lymphopoiesis, may provide a more complete picture of leukemic differentiation. It is anticipated that such a model will be useful in devising new therapies.

Cell Survival↗
PubMed1978

Cytodifferentiation in the acute myeloblastic leukemias of man.

Correlation analysis of numbers of colony-forming progenitor cells was used as an approach to the quantitation of human pluripotent stem cells. Marrow specimens were obtained from 24 patients with untreated acute myeloblastic leukemia, 22 patients under treatment, and 29 patients with no hematologic malignant disease. Three classes of progenitor cells were assayed: burst-forming units dependent on erythropoietin (BFU-E), colony-forming units dependent on erythropoietin (CFU-E), and granulopoietic progenitors (CFU-C). Significant positive correlations between numbers of BFU-E, CFU-E, and CFU-C were found in all 3 groups of patients. In contrast, no such positive correlations were seen between marrow blasts and any of the classes of colony-forming progenitors. These results were compatible with a shared relationship of the colony-forming progenitors to a pluripotent cell of origin and raised the possibility that the immediate progenitors of the blasts may not be any of the myelopoietic progenitor cells monitored in these studies.

Adult↗
PubMed1978

Proliferative state of blast cell progenitors in acute myeloblastic leukemia (AML).

Peripheral blood from patients with acute myeloblastic leukemia (AML) contains cells capable of giving rise to colonies in culture when stimulated by media conditioned by leukocytes (LCM) in the presence of phytohemagglutinin (PHA). Two types of colonies are recognized with high frequency: The first grows in the presence of low concentrations of PHA LCM, have a blast-like morphology, and are numerically correlated with morphologically identified blast cells. The second requires either high PHA LCM concentrations or PHA alone with or without 2-mercaptoethanol and consists of cells capable of forming rossettes with sheep erythrocytes and resembles. T-lymphocyte colonies from normal blood. Precursors of blast cell colonies from 15 leukemic patients were tested for cycle state, using either the 3H-thymidine or hydroxyurea techniques. All were found to have a high proportion of cells in the S phase of the cycle. In contrast, T lymphocyte precursors from three normal individual were quiescent. The data are consistent with the maintenance of the leukemic blast cell populations by the proliferative activity of a small subpopulation of blasts.

Adult↗
PubMed1978

The production of hemopoietic growth factors by PHA-stimulated leukocytes.

Conditioned medium from cultures of phytohemagglutinin-stimulated leukocytes has been assessed for its content of factors able to stimulate either colony formation by human granulopoietic progenitor cells, or 3H-thymidine incorporation by peripheral leukocytes from leukemic patients. The cell concentration, concentration of phytohemagglutinin and time required for optimal production of factors were investigated. Production of both classes of factors was found to be insensitive to inhibitors of cell proliferation and DNA synthesis, but sensitive to inhibition of protein synthesis by cycloheximide. The production of colony stimulating activity showed a markedly greater sensitivity to cycloheximide than did production of thymidine-incorporating activity. For cycloheximide and most of the other inhibitors studied, factor production by leukemic cell populations was affected to a somewhat greater extent than production by normal leukocytes. Separation by velocity sedimentation of the cells responsible for production provided no evidence for distinct classes of cells producing these two classes of factors.

Cell Division↗
PubMed1978

Clonal expansion and progression in acute myeloblastic leukemia.

Diseaes originating in pluripotent stem cells, then developing through clonal expansion and clonal progression may properly be grouped together because of their common features. Among these, AML appears to be unique by reason of the presence within the clone of a blast cell population. Studies of cellular composition and regulation in AML clones require assays that measure not only myelopoiesis but also blast cell proliferation. The relation of the blast population to other components of AML clones remains uncertain. Resolution of the uncertainty is important in considering therapeutic strategies.

Bone Marrow Cells↗
PubMed1977

Differentiation in human myeloblastic leukemia studied in cell culture.

Normal adult hemopoiesis orginates in pluripotent stem cells; among the early differentiated descendents of such cells are progenitors committed to the erythropoietic, granulopoietic, or megakaryocytic pathways of myeloid differentiation. These may be detected in cell culture by developmental techniques, in which progenitors form colonies in viscid or semisolid media in response to appropriate stimulation. Certain diseases of hemopoiesis also originate in pluripotent stem cells; these include chronic myeloblastic leukemia, acute myeloblastic leukemia, polycythemia vera, and idiopathic myelofibrosis-the clonal hemopathies. The hypothesis is advanced that the distribution of cell classes among patients with clonal hemopathies is determined both by the differentiation potential of each pluripotent stem cell maintaining an abnormal clone and by random events occurring during clonal expansion. The latter process may account for the large variations observed between patients when committed progenitors are assayed in cultures of marrow from patients with acute myeloblastic leukemia (AML). This variation may also be used to estimate lineage relationships in the clonal hemopathies. When applied to myelopoiesis in AML, obvious differences from the normal are not detected. The analysis is consistent with the view that the blast cell population in AML is distinct from the leukemic myelopoiesis occurring within an abnormal clone. A new assay procedure is described for progenitor cells related to blast cell proliferation. Finally, these concepts are used to develop a model for the pathogenesis and cellular characteristics of AML.

Cells, Cultured↗
PubMed1976

Antibodies in human sera to oncorna virus-like proteins from normal or leukemia marrow cell cultures.

Some human marrows in culture release particles with oncornavirus-like properties. This study was designed to examine the immunological properties of similar particles in human marrow culture supernates. Leukemic and nonleukemic marrows were cultured for 5-7 days in the presence of [14C]uridine and [3H]leucine or [3H]glucosamine. Labeled supernatant components banding in sucrose gradient densities of 1.20-1.24 g/ml were used as antigen in a double antibody immunoprecipitation assay. The assay was validated by end point titrations and competition with unlabeled antigen; purified myeloma proteins were used as negative controls. Cross-reactivity with mammalian oncornaviruses, as judged by competitive inhibition of precipitation by these viruses, was slight and at the border of the sensitivity of the method. Precipitated antigens analyzed by SDS polyacrylamide gel electrophoresis contained three distinct polypeptides of about 70,000, 45,000 and 30,000 mol wt; these comigrated with the gp 70, pg 45, and p 30 of a murine leukemia virus. Similar polypeptides were obtained from both leukemic and nonleukemic marrow culture supernates. As determined by the radioimmunoprecipitation assay, 32 of 45 leukemic sera (71%), 36 of 45 normal sera (80%), 15 of 19 sera from family contacts of leukemic patients (79%), 14 of 21 cord blood specimens (67%), and 21 of 23 sera (91%) from patients with systemic lupus erythematosus had detectable antibody activity.

Antibodies, Viral↗