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

Rat basophilic leukemia cells were labeled either enzymically with 125I or biosynthetically by culture in the presence of 14C-glucosamine or 3H-amino-acids and then extracted with NP-40. IgE-anti-IgE precipitates insolubilized a radiolabeled macromolecule from these extracts largely or entirely absent in control IgG-anti-IgG percipitates. When specific precipitates were boiled in sodium dodecyl sulfate (SDS) and analyzed by polyacrylamide gel electrophoresis in the presence of SDS, most of the 14C or 125I radioactivity was in the area corresponding to an apparent m.w of 60,000 to 70,000 in 5.9% gels. In 10% and 12% gels, faster mobility was demonstrated indicating an atypical electrophoretic behavior often associated with glycoproteins and a presumptive m.w. of 50,000 or less. Since only IgE-containing precipitates localized label in this region and since such precipitates from cells saturated with IgE prior to surface iodination failed to show this band, the labeled macromolecule appears to be the IgE receptor itself. Analysis of the acid hydrolysates of precipitated 14C radioactivity demonstrated that label was entirely in hexosamines and sialic acid. 125I and 14C labels in the recepotr region were eliminated almost completely with pepsin and pronase and to a lesser extent with trypsin.
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PMID:The rat basophilic leukemia cell receptor for IgE. I. Characterization as a glycoprotein. 82 Aug 4

Three assays of cell-mediated cytotoxicity in mice, involving release of either 51Cr (CRA), 125iododeoxyuridine (IRA), or [3H]proline (PRA), were compared under identical test conditions. Experiments were performed with effector cells from mice immunized with FBL-3 tumor cells, a syngeneic Friend virus-induced leukemia, or with allogeneic normal spleen cells. With established tissue culture cells as targets, similar results were obtained in all three assays. The cytotoxicity produced by cells from in vivo-immunized mice and the induction of cytotoxicity in vitro were T-cell-dependent. When short-term culture target cells were used, the IRA gave a more selective pattern of cytotoxicity than did the other two assays. However, when remaining target cells at the end of the assay were treated with trypsin, higher levels of 125iododeoxyuridine (125IUDR) release were seen, and the results were then comparable to those in the CRA and PRA. These results indicated that 125IUDR, a nuclear label, could only be released after lysis of cells. In contrast, 51Cr or [3H]proline, which are cytoplasmic labels, could also be released from damaged but unlysed cells. These fundamental differences could give different results in these assays, which could determine their correlation with in vivo transplantation immunity.
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PMID:Comparison of three isotopic assays of cell-mediated cytotoxicity against mouse tumor cells. II. Sensitivity and specificity of the assays and characteristics of effector and sensitizing cells. 83 81

Purified gp71 of Friend murine leukemia virus (FLV) can interfere with virus infection, absorb neutralizing antibody, and in the presence of group-specific anti-gp71 antibody, hemagglutinate sheep erythrocytes. Interference by FLV gp71 with several murine leukemia viruses (MuLV) was tested in the XC and S + L- assay systems. Treatment of gp71 with trypsin or Pronase eliminated its interfering capacity. However, treatment with neuraminidase or a mixture of glycosidase enzymes, which left the major serological properties of gp71 intact, did not reduce the interference potential of gp71 for FLV or AKR MuLV. The capacity of gp71 to absorb type- or group-specific virus-neutralizing antibodies was similarly affected by the various enzyme treatments. In contrast, indirect hemagglutination by gp71 was abolished not only by proteases but also by treatment with glycosidase enzymes, although neuraminidase had no effect. Preliminary data indicate that infectivity of FLV or xenotropic MuLV was not affected by short treatment with glycosidase enzymes.
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PMID:Role of carbohydrate in biological functions of Friend murine leukemia virus gp71. 83 28

Immune cytolysis (lysis) of cells due to the action of antibody in the presence of complement is usually substantiated by the uptake of vital dye by the cells, or by the escape of radiolabel from the cells. Immune cytolysis has now been assayed by determination of cell volume distribution with a Coulter multi-channel particle size analyser used in conjunction with a Coulter counter. For Ehrlich ascites and sarcoma-180 cells, volume degradation corresponding to vital staining was obtained only if trypsin (final concentration 625 microgram/ml) was added immediately after the usual 1 h incubation period for cells, antibody and complement. For L1210 leukaemia cells, trypsin was added at 0 degrees just 1 min before Coulter evaluation, to avoid potentiation of antibody-mediated cell lysis by trypsin. Immune cytolysis of mouse thymic, splenic and lymph node lymphocytes required addition of pronase (final concentration 625 microgram/ml) at 0 degrees for further disruption of antibody-damaged cells, prior to determination of cell volume distribution in the Coulter equipment. Scanning electron micrographs of L1210 cells undergoing immune cytolysis illustrated the changes in cell volume recorded by the Coulter apparatus. This new method for determination of immune cytolysis provides detailed information about the volume distribution of target cells, which permits detection of subtle changes and gives insight into the process of cytolysis. It is not intended to displace other procedures in routine use, except that complete automation of the present method is possible in future.
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PMID:Assay of immune cytolysis of lymphocytes and tumour cells by automatic determination of cell volume distribution. 87 76

A method is described for radioiodination to high specific activity of fixed and stained proteins within sodium dodecyl sulfate-polyacrylamide gels, without elution of the proteins from the gel. Following radioiodination, the proteins can be removed from the gel by trypsin treatment and the peptides analyzed. This procedure offers a means to structurally compare the proteins of multicomponent systems when purification of each component to homogeneity is unfeasible. Using this technique, we have compared the tryptic peptides of all the major protein components of Moloney and Rauscher leukemia viruses using only 50 to 100 microgram of total protein from each virus. Additionally, we have analyzed the membrane proteins of Dictyostelium discoideum at various stages in development. The validity of the technique and its value as a tool for comparative studies and identification of precursor-product relationships is discussed.
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PMID:Radioiodination of proteins in single polyacrylamide gel slices. Tryptic peptide analysis of all the major members of complex multicomponent systems using microgram quantities of total protein. 89 22

Rapid degradation of ascites tumor cells damaged by the action of antibody plus complement was found to be accomplished by all proteolytic enzymes active at physiologic pH that were tested. For three types of murine ascites tumor cells (Ehrlich ascites, sarcoma-180, and L1210 leukemia), this rate of degradation at low trypsin concentrations was proportional to a high power of enzyme concentration. This suggests that the simultaneous action of two or more enzyme molecules at adjacent cell surface sites is necessary. Cell degradation was assayed by determination of cell volume distribution with a Coulter multi-channel particle size analyzer. The present study may offer clues to in vivo mechanisms of cell degradation.
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PMID:Enzymatic degradation of tumor cells damaged by antibody plus complement. 98 39

A simple liquid culture technique has been used to study peripheral blood from patients with acute myelogenous leukaemia. Evidence is presented that cells from morphologically identical types of leukaemia have differing capacity for "differentiation" from free floating blast cells into plastic-adherent phagocytic, trypsin-resistant macrophage-like cells with Fc and C3 receptors. Preliminary analysis suggests that patients whose cells have the greatest capacity for "differentiation" have a better chance of achieving complete remission.
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PMID:Diagnostic and prognostic significance of peripheral blood cultural characteristics in adult acute leukaemia. 106 91

Previous reports have shown that spleen cells from nonimmune adult mice of certain strains do regularly kill Moloney leukemia virus-induced lymphomas in short-term 51Cr release assays. This naturally occuring killer (NK) cell had low adherent properties and had the morphological appearance of a lymphocyte. Still it lacked surface characteristics of mature T or B lymphocytes. In the present report a functional study was carried out, comparing in parallel the NK system, the T-cell killing across an H-2 barrier (anti-P815), and the antibody-dependent cell-mediated chicken red blood cell (CRBC) system. In contrast to the effector cells in the CRBC system, the NK cells were insensitive to erythrocyte antibody complement (EAC) rosette depletion and would pass through nylon wool columns. NK activity was not inhibited by the presence of heat-aggregated human or mouse gamma globulin, in contrast to the strong inhibition noted in the CRBC system. Sensitivity to trypsin pretreatment was noted in the NK system as well as in the immune P815 system, whereas the CRBC system was relatively trypsin resistant. Antitheta plus complement eliminated the anti-P815 activity, but did not touch the NK activity. The present results thus further distinguish the NK cell from cytotoxic T lymphocytes or from antibody-dependent killer cells.
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PMID:Killer cells: a functional comparison between natural, immune T-cell and antibody-dependent in vitro systems. 108 15

Several of the cannabinoids found in marihuana have been shown to inhibit tumor growth and increase the life-span of mice bearing the Lewis lung adenocarcinoma. When trypsin-dispersed isolated Lewis lung cells are incubated in vitro, they maintain their capacity to carry out macromolecular synthesis (RNA, DNA, protein). This process can be inhibited by cytosine arabinoside, actinomycin D, or methyl-1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea, whereas cyclophosphamide, an agent that must be bioactivated, was inactive. Inhibition of DNA synthesis as measured by [3H]thymidine uptake into acid-insoluble material was used as an index of cannabinoid activity against isolated Lewis lung cells, L1210 leukemia cells, and bone marrow cells incubated in vitro delta9-, delta8-, 1-hydroxy-3-n pentyl-, and 1-delta8-tetrahydrocannabinol, and cannabinol demonstrated a dose-dependent inhibition of DNA synthesis whereas cannabidiol and 1-hydroxy-3-n-pentylcannabidiol were markedly less inhibitory in our in vitro cell systems. Furthermore, our in vitro observations with these cannabinoids are supported by in vivo tumor inhibition studies. Ring modifications as in cannabichromene or cannabicyclol abolish in vitro activity as does dihydroxylation at the 8beta and 11 positions of 1-delta9-trans-tetrahydrocannabinol. Delta9-trans-tetrahydrocannabinol demonstrated the least toxicity of all inhibitory cannabinoids in vivo; this is supported by its lesser effect on bone marrow DNA synthesis in vitro.
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PMID:The inhibition of DNA synthesis by cannabinoids. 124 11

The changes occurring in the hematopoietic extracellular matrix in an experimental myeloproliferative syndrome were explored by comparing the glycosaminoglycan (GAG) composition of normal mouse spleens and spleens infected with myeloproliferative sarcoma virus (MPSV). Large quantities of hyaluronate and of sulfated GAGs accumulated in the extracellular matrix of infected spleens, as shown by histoimmunoassay and alcian blue staining, respectively. The splenic GAGs were either labeled with 35S-sulfate injected in vivo or unlabeled. The spleens were fractionated to separate hematopoietic cells from the stromal component containing extracellular matrix material and fibroblasts, and the GAGs were extracted from each fraction. Specific degradative treatments and electrophoresis indicated that sulfated GAGs were mostly chondroitin sulfate and heparan sulfate. Three hours after in vivo injection of 35S-sulfate, the amount of 35S-GAGs was increased approximately fivefold per mg stromal proteins. The bulk of these 35S-GAGs (70%) was recovered in the stromal fraction. The higher amount of sulfated GAGs in leukemic spleen was due both to the presence of more producer cells (infected fibroblasts and hematopoietic cells) and to a stimulation of GAG synthesis per cell, as evidenced 35S-labeling in in vitro experiments. Chondroitin sulfate was the main sulfated GAG present in the culture medium of both hematopoietic and fibroblastic cells and in the pericellular material released by trypsin from fibroblastic cells. High amounts of chondroitin sulfate, which has a possible role in the detachment of hematopoietic cells from the stromal cells, may favour the release of hematopoietic cells from the spleen into the peripheral blood. Heparan sulfate was produced by fibroblastic cells and it was principally present in their pericellular material. Considering the capacity of heparan sulfate to retain cytokines, as demonstrated by others in vitro, large amounts of heparan sulfate may result in the retention of large amounts of the cytokines, which production is enhanced in the infected spleen. This phenomenon may contribute to promote the hematopoietic stem cell proliferation characteristic of the MPSV-induced myeloproliferative disease.
Leukemia 1992 Oct
PMID:Increased synthesis of extracellular spleen glycosaminoglycans in an experimental myeloproliferative syndrome. 132 75


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