Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have examined the electrophoretic mobility on sodium dodecyl sulfate-polyacrylamide gels of three virion proteins of B-tropic murine leukemia virus from BALB/c and six of its NB-tropic derivatives. The gp70 protein and a 13,000-molecular-weight virion protein tentatively identified as p15 of the NB-tropic viruses migrated with the corresponding B virus proteins. However, the major internal structural protein of type C virions, p30, of all the NB-tropic viruses migrated more rapidly than the p30 of their B virus progenitor. Although this change in p30 raises the possibility that p30 may be involved in determining the N-, B-, or NB-tropism of MuLV's, it is also possible that the change accompanies but does not directly determine the change in tropsim.
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PMID:Six-NB-tropic murine leukemia viruses derived from a B-tropic virus of BALB/c have altered p30. 18 69

The synthesis and processing of feline leukemia virus (FeLV) polypeptides were studied in a chronically infected feline thymus tumor cell line, F-422, which produces the Rickard strain of FeLV. Immune precipitation with antiserum to FeLV p30 and subsequent sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) were used to isolate intracellular FeLV p30 and possible precursor polypeptides. SDS-PAGE of immune precipitates from cells pulse-labeled for 2.5 min with [35S]methionin revealed the presence of a 60,000-dalton precursor polypeptide (Pp60) as well as a 30,000-dalton polypeptide. When cells were grown in the presence of the proline analogue L-azetidine-2-carboxylic acid, a 70,000-dalton precursor polypeptide (Pp70) was found in addition to Pp60 after a 2.5-min pulse. The cleavage of Pp60 could be partially inhibited by the general protease inhibitor phenyl methyl sulfonyl fluoride (PMSF). This partial inhibition was found to occur only if PMSF was present during pulse-labeling. Intracellular Pp70 and Pp60 and FeLV virion p70, p30, p15, p11, and p10 were subjected to tryptic peptide analysis. The results of this tryptic peptide analysis demonstrated that intracellular Pp70 and virion p70 were identical and that both contained the tryptic peptides of FeLV p30, p15, p11, and p10. Pp60 contained the tryptic peptides of FeLV P30, P15, and P10, but lacked the tryptic peptides of P11. The results of pactamycin gene ordering experiments indicated that the small structural proteins of FeLV are ordered p11-p15-p10-p30. The data indicate that the small structural proteins of FeLV are synthesized as part of a 70,000-dalton precursor. A cleavage scheme for the generation of FeLV p70, p30, p15, p11, and p10 from precursor polypeptides is proposed.
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PMID:Analysis of intracellular feline leukemia virus proteins II. Generation of feline leukemia virus structural proteins from precursor polypeptides. 19 17

cCMP-specific phosphodiesterase activity was demonstrated in the 80 to 100% ammonium sulfate fraction obtained from disrupted leukemia L-1210 cells. The activity was linear with time (up to 60 min), was a function of protein concentration, and was markedly stimulated by Mg2+ and by ammonium sulfate. Under identical assay conditions, no significant hydrolysis of cAMP or cGMP was observed, although these cyclic nucleotides served as substrates for phosphodiesterase(s) present in all the fractions obtained by less than 80% ammonium sulfate saturation. This is the first demonstration of a cCMP-specific phosphodiesterase.
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PMID:Demonstration, in leukemia L-1210 cells, of a phosphodiesterase acting on 3':5'-cyclic CMP but not on 3':5'-cyclic AMP or 3':5'-cyclic GMP. 20 54

To examine the protein proximity and subunit organization of type C retroviruses, preparations of AKR murine leukemia virus were treated with bifunctional cross-linking reagents and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The cross-linked components obtained were characterized by immunoprecipitation with monospecific antisera against purified viral proteins, followed by SDS-PAGE analysis both before and after cleavage of the cross-links. With these procedures, complexes of both viral envelope and core components were identified. The major envelope subunit obtained was a large (apparent molecular weight of 450,000 to 500,000), glycosylated complex, composed of four to six gp70-p15(E) subunits. This complex was detected over a 100-fold range of cross-linker concentration and thus seems to represent a particularly stable viral substructure. The cross-linked complexes of the core proteins consisted of oligomers of p30 dimers, suggesting that the p30 dimer is a basic structural unit of the viral core. When virion preparations, which had previously been disrupted with the nonionic detergent Nonidet P-40, were cross-linked, the envelope complex was still observed, indicating that this structure is stable in the presence of Nonidet P-40. A similar envelope structure was observed for feline leukemia virus, suggesting that such a complex may be a conserved feature of oncornavirus structure.
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PMID:Structural studies of retroviruses: characterization of oligomeric complexes of murine and feline leukemia virus envelope and core components formed upon cross-linking. 22 13

Comparison of a number of murine leukemia virus clones by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed extensive protein polymorphism among B-tropic, but not N-tropic, isolates from BALB/c mice, particularly in migration of p30 proteins. A type-specific radioimmunoassay for p30 was developed which uniformly discriminated all B-tropic viruses from N-tropic viruses of BALB/c origin. N- and B-tropic viruses of C57BL/6 and AKR Fv-1b/b origin could also be distinguished by this assay.
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PMID:Polymorphism of B-tropic leukemia viruses from BALB/c mice: association of a p30 antigen with N- versus B-tropism. 23 84

Aggressive treatment with cytarabine, vincristine sulfate, and prednisone for acute myelogenous leukemia, administered from the 31 st week of pregnancy, resulted in both sustained complete remission of the leukemia and delivery of a normal infant with a normal birthweight and a normal male karyotype. It is concluded that chemotherapy with cytarabine combinations can be administered in the third, and probably the second, trimester of pregnancy without risk of serious damage to the developing fetus.
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PMID:Successful treatment of acute leukemia during pregnancy. Combination therapy in the third trimester. 26 69

This work describes the detection, isolation, and partial characterization of a BALB/c mouse fibroblast cell surface antigen. This antigen migrates as a polypeptide of approximately 100,000 daltons in a discontinuous sodium dodecyl sulfate/polyacrylamide gel electrophoresis system, can be labeled by either lactoperoxidase-catalyzed cell surface 125I iodination or metabolic incorporation of [3H]glucosamine, and can be isolated by concanavalin A affinity chromatography. This cell surface glycoprotein is antigenic in BALB/c mice and has been correlated with the rejection of immunogenic tumor cells. Also, antiserum specific for Moloney leukemia virus precipitates the 100,000-dalton cell surface protein from viral and immunogenic spontaneous transformants. This virus-related antigen comigrates on sodium dodecyl sulfate gels with the major iodinated cell surface protein of these transformants. Rabbit antiserum to the purified antigen demonstrates a marked preference for the surfaces of immunogenic tumor cells as compared with normal cells and nonimmunogenic tumor cells.
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PMID:Isolation and characterization of a tumor cell surface antigen from spontaneously transformed BALB/c mouse fibroblasts. 28 13

We have labeled surface glycoproteins of normal and malignant human blood leukocytes by the galactose oxidase-NaB3H4 and periodate-NaB3H4 labeling techniques. The labeled glycoproteins were separated by slab gel electrophoresis in the presence of sodium dodecyl sulfate and visualized by fluorography. The different types of normal blood cells could be distinguished by their surface glycoprotein patterns. The surface glycoproteins of cells from patients with acute lymphoblastic, myeloid, or monoblastic leukemia were different from those of normal cells. The leukemic cells could be classified by their surface glycoprotein patterns with respect to their relationships to normal blood cells, and an estimation of their degree of differentiation was obtained.
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PMID:Identification and characterization of normal and malignant human blood leukocytes by surface glycoprotein patterns. 29 63

L1210 murine leukemia and CEM human lymphoblastoid leukemia cells were exposed to vincristine sulfate in vitro. The response of these cell lines to this agent was measured by the colony-forming ability of L1210 cells in soft agar and inhibition of growth of CEM in suspension culture. Incremental increases of vincristine concentrations in excess of 2 x 10(-9) M produced a progressive reduction of survival of L1210 cells and suppression of CEM growth under the condition of constant drug exposure. A maximum cytotoxic effect was reached with drug concentrations between 10(-8) and 10(-7) M. When L1210 cells were exposed to vincristine for a variable length of time ranging from 0.5 to 24 hr, 10(-7) M produced a noticeable cytotoxic effect following an incubation of only 30 min. A 50% cell kill of L1210 cells and a 50% reduction of CEM cell growth were produced by 10(-7) M following a 1- to 3-hr period of exposure; 6 to 12 hr were required to produce a similar effect at a vincristine concentration of 10(-8) M. Therefore, the antitumor effect of vincristine is critically dependent on both concentration and duration of exposure. These data suggest the possibility that the effectiveness of vincristine as an antitumor agent could be enhanced if methods are developed to prolong exposure of neoplastic tissues for longer periods of time than currently produced by conventional methods of administration.
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PMID:Cytotoxic thresholds of vincristine in a murine and a human leukemia cell line in vitro. 29 76

Human thymus-leukemia-associated antigen (HThy-L), a saline-soluble antigen, was previously detected by immunodiffusion (but not on the cell surface) in significant quantity in extracts of normal thymocytes, cells from cultured T-cell lines, and erythrocyte-rosette-positive leukemia blasts. Two species of HThy-L were identified and isolated from normal human thymus tissue after extraction in tris buffer, ammonium sulfate fractionation, acid precipitation of inactive fractions, DEAE-cellulose (DE-52) chromatography, Sephadex G-100 gel filtration, and carboxymethyl-cellulose (CM-52) chromatography; On Sephadex G-100, both HThy-L species had a similar molecular weight (40,000--50,000), but they eluted in different positions on DE-52 and CM-52. Analysis by sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that each of the 2 HThy-L species contained 2 components with molecular weights of approximately 43,000 and 23,000. Further purification of HThy-L on Sephadex G-50 showed that the 43,000-dalton component possessed HThy-L activity.
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PMID:Human thymus-leukemia-associated antigen: isolation and partial characterization. 30 95


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