concanavalin-a and Precursor-Cell-Lymphoblastic-Leukemia-Lymphoma

The FURA-2/AM fluorescence dye was used to investigate the influence of dexamethasone treatment on the basal and mitogen-mediated levels of free ions of calcium ([Ca++]i) in the lymphoblast cytoplasm from bone marrow of patients suffering acute leukemia. Treatment with dexamethasone in the dose of 2 microM was shown to significantly stimulate the increase of the basal level of [Ca++]i and to inhibit the Ca++ response of cells to concanavalin A (25 micrograms/ml). Inhibition by dexamethasone was more pronounced after 30 min preincubation of lymphoblasts with a glucocorticoid. A phorbol ester--phorbol myristate acetate--reactivated sensitivity to concanavalin A in dexamethasone-treated cells. Determination of lymphoblast Ca(++)-response of dexamethasone treatment may be used for in vitro express testing individual sensitivity to glucocorticoids in treatment of acute leukemia.

Topics: Bone Marrow; Bone Marrow Cells; Calcium; Concanavalin A; Dexamethasone; Fluorescent Dyes; Humans; In Vitro Techniques; Lymphocytes; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Tetradecanoylphorbol Acetate

In an attempt to better characterize leukemic bone marrow cells of children with ALL in G0/G1, we studied the variation of the nuclear projection area (NPA) during the cell cycle. Approximately half of the increase of the nuclear volume during the cell cycle occurred before DNA synthesis. Next, we assessed by in situ hybridization (ISH) the expression of nuclear envelope type A/C and type B lamins in leukemic lymphoblast and unstimulated as well as stimulated normal peripheral blood mononuclear cells (PBMC). It was found that 82.0 +/- 16.0% of the ALL cells expressed B-type and 5.8 +/- 3.1% A/C-type lamins. The in vitro 3HdT pulse-labeling index (3HdT LI) of ALL cells varied from 1.3 to 16.8%. Of unstimulated PBMC 2.9 and 1.2% expressed lamin type B and A/C, respectively. The 3HdT LI was 0.8%. In conA-stimulated PBMC, the corresponding values were 95.3 and 74.8% and 31.0%, respectively. In view of the current concepts regarding G1 events and regulation of cell proliferation, we considered B-type lamin expression an early marker for the commitment to proliferation and used it for growth fraction (GF) determinations. By this method, a surprisingly high GF was found in ALL cell populations; there was no correlation between GF and the 3HdT LI, as seen in normal cells.

Topics: Adolescent; Cell Division; Cell Nucleus; Child; Child, Preschool; Concanavalin A; Cytophotometry; DNA, Neoplasm; Female; Gene Expression; Humans; In Situ Hybridization; Lamins; Male; Neutrophils; Nuclear Proteins; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Stimulation, Chemical

In a previous study we characterized cancer procoagulant (CP), a 68 kd cysteine proteinase which directly activates coagulation factor X in various subtypes (from M1 to M5) of acute non-lymphoblastic leukemia (ANLL). The aim of this study was to determine whether CP is also expressed by acute lymphoblastic leukemia (ALL) cells. Blasts from 25 ALL patients were extracted and tested for their procoagulant properties. 16 samples (64%) shortened the recalcification time of normal human plasma, and 9 (36%) did not. 8 of the 16 active samples showed properties compatible with CP, i.e. independence from factor VII in triggering blood coagulation and sensitivity to cysteine proteinase inhibitors. Selected samples also cross-reacted with a polyclonal antibody raised against purified CP. The specific activity of CP in ALL extracts was significantly lower than in most ANLL types previously studied (all but M4). These finding indicate that CP can be a property of the lymphoid phenotype although its expression may be lower than in the myeloid phenotype.

Topics: Adolescent; Adult; Blood Coagulation Factors; Bone Marrow; Child; Child, Preschool; Concanavalin A; Cysteine Endopeptidases; Female; Humans; Iodoacetamide; Male; Mercuric Chloride; Middle Aged; Neoplasm Proteins; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Reference Values

Lymphocytes from acute lymphocytic leukemia (ALL) subjects were converted by mitogens to blast-like cells whose microscopic appearance and rate of formation was indistinguishable from those in mitogen incubated control lymphocytes. In ALL lymphocytes, however, pokeweed mitogen (PWM) failed to stimulate GGT expression; the mean increase it caused in thymidine kinase (TK) activity and thymidine incorporation was normal, though there were appreciable individual variations. These variations were also apparent with concanavalin A (Con A) but, in most ALL cases, TK and thymidine incorporation rose to much higher levels than in Con-A-treated control lymphocytes. The results indicate that evaluation of the response to mitogens by quantitative biochemical criteria provides a sensitive method for revealing functional impairments in microscopically normal ALL lymphocytes.

Topics: Cells, Cultured; Concanavalin A; DNA Replication; gamma-Glutamyltransferase; Humans; Kinetics; Lymphocyte Activation; Lymphocytes; Pokeweed Mitogens; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Reference Values; Thymidine Kinase