suppression. The lymphoblasts of children were more sensitive to MTX than were the lymphoblasts of adults. When patients with acute lymphoblastic leukemia were put into remission and maintained with MTX, there was a correlation between sensitivity to MTX in vitro and length of remission. There was also a correlation between in vitro effect of MTX and duration of survival, and the correlation wa...

Treatment of MOLT F4 lymphoblasts with 6-mercaptopurine (6-MP) resulted in a decrease of ATP and a depletion of S-adenosylmethionine (AdoMet). To investigate whether this might affect the methylation of DNA, we treated MOLT F4 lymphoblasts with increasing concentrations of 6-MP, followed by labeling with [methyl-14C]methionine and [methyl-3H]thymidine. After DNA isolation, we measured the incor...

Normal precursor B cells or hematogones share morphologic and immunophenotypic similarities with lymphoblasts of precursor B-lymphoblastic leukemia. The numbers are often increased and difficult to distinguish in many patients following chemotherapy for precursor B-lymphoblastic leukemia. The purpose of this study was to establish a unique method for differentiating hematogones from lymphoblast...

Terminal deoxynucleotidyl transferase activity and cell surface markers were measured in peripheral lymphoid cells from 27 children with acute lymphoblastic leukemia in various phases of their disease. Lymphoblasts from untreated patients had smooth surface ultrastructure but heterogeneous surface receptors. Greater than 60% of lymphoblasts from 4 to 7 untreated patients formed rosettes with sh...

-Ultrafiltrates from spleen inhibited both DNA synthesis and the proliferation of normal lymphocytes stimulated in culture from both mouse and man without apparent cytotoxicity. However, the same doses of this spleen ultrafiltrate will kill up to two-thirds of the leukaemic lymphoblasts from both mouse and man after 24 h incubation. This unique lymphocytotoxic effect could also be demonstrated ...

A chemotactic factor inhibitor (CFI) was found in the serum of a patient with acute lymphoblastic leukemia. The factor was characterized as heat-labile, with activity against complement-dependent chemotactic factors and against the chemotactic factor produced by Escherichia coli. Normal sera and sera from other patients with acute leukemia also demonstrate heat-labile inhibitory activity agains...

The important role of lymphocytes in humoral and cell-mediated immunity indicates that they need a readily available intracellular source of energy. Here, we demonstrate that these cells contain enzymes involved in citrate formation. The citrate is oxidized through the tricarboxylic acid cycle to furnish energy. A newly devised, simple radiometric method was used to determine the condensation o...

1. A Golgi-apparatus-enriched fraction was isolated from acute leukaemic lymphoblasts of AKR mice by using an homogenate stabilized with 1 mM-glutaraldehyde. 2. The isolated fraction, which was shown morphologically to be enriched in dictyosomes, possessed between 44- and 76-fold increase in specific activity, compared with the tumour homogenate, of UDP-galactose-glycoprotein galactosyltransfer...

We describe here the use of fluorescence in situ hybridization (FISH) to measure the transfection efficiency of the transient expression vector pCMVcat in lymphoblasts and fibroblasts. By using a pCMVcat probe, we can visualize the location of the plasmid after transfection and thus determine transfection efficiency. In this report, we show that, for transfection of pCMVcat by the diethylaminoe...

Adenosine deaminase has been measured by the indirect spectrophotometric method in lymphoblasts from adult and pediatric lymphoblastic leukemias, peripheral T- and B-cells, mature T-cell leukemia (Sézary cell), and mitogen-stimulated peripheral control T- and B-cells. It was found that, if the specific activity of the enzyme is expressed in terms of cell cytoplasmic protein concentration rather...