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)

The mode of influx of 86Rb+, a K+ congener, to exponentially proliferating L1210 murine leukemia cells, incubated in a Krebs-Ringer buffer, has been characterised. The influx was composed of a ouabain-sensitive fraction (approx. 40%), a loop diuretic-sensitive fraction (approx. 40%) and a fraction which was insensitive to both types of inhibitor (approx. 15%). The fraction of ouabain-insensitive 86Rb+ influx, which was fully inhibited by furosemide (1 mM) or bumetanide (100 microM), was completely inhibited when Cl- was completely substituted by nitrate or gluconate ions, but was slightly (29 +/- 12%) stimulated if the Cl- was substituted by Br-. The substitution of Na+ by Li+, choline or tetramethylammonium ions inhibited the loop diuretic-sensitive fraction of 86Rb+ uptake. These results suggested that a component of 86Rb+ influx to L1210 cells was mediated via a Na+/K+/Cl- cotransporter. 86Rb+ efflux from L1210 cells which had been equilibrated with 86Rb+ and incubated in the presence or absence of 1 mM ouabain, was insensitive to the loop diuretics. Additionally, efflux rates were found to be independent of the external concentration of K+, suggesting that efflux was not mediated by K+-K+ exchange. The initial rate of 86Rb+ influx to L1210 cells in the plateau phase of growth was reduced to 44% of that of exponentially dividing cells, the reduction being accounted for by significant decreases in both ouabain- and loop diuretic-sensitive influx; these cells were reduced in volume compared to cells in the exponential phase of cell growth. In cells which had been deprived of serum for 18 h, and which showed an increase of the proportion of cells in the G1 phase of the cell cycle, the addition of serum stimulated an immediate increase in the furosemide-sensitive component of 86Rb+ influx. Diuretic-sensitive 86Rb+ influx was not altered by the incubation of the cells with 100 microM dibutyryl cyclic AMP, but was inhibited by 10 microM of the cross-linking agent nitrogen mustard (bis(2-chloro-ethyl)methylamine, HN2).
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PMID:Characterisation of a Na+/K+/Cl- cotransporter in alkylating agent-sensitive L1210 murine leukemia cells. 320 51

The study employing labelled precursors of nucleic acids with their double-strand structure was identified by bromide ethidium. In addition, the application of hemocarboperfusion revealed active and irreversible adsorption of nucleic acids and nucleoproteids from ascitic fluid of mice with NKLy leukemia and from plasma of leukemia patients.
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PMID:Plasma nucleic acid adsorption on charcoal sorbents in patients with leukemia. 325 38

We have recently shown that glucocorticoids dramatically increase the number of interleukin 1 (IL 1) receptors on human peripheral blood mononuclear cells (PBMC) and that IL 1 selectively induces the phosphorylation of a cytosolic 65-kilodalton (kDa) protein (pp 65) in glucocorticoid-pretreated PBMC. We describe here the purification and biochemical characteristics of pp 65. 32P-Labeled pp 65 was purified to homogeneity from the cytosol fraction of IL 1 stimulated [32P]orthophosphate-labeled PBMC by sequential chromatography on Sephacryl S-200, high-performance liquid chromatography (HPLC) anion exchange, and hydroxyapatite HPLC. The purified pp 65 was homogeneous on sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. The unphosphorylated 65-kDa protein (p 65) was also purified to homogeneity in a similar way. About 40 micrograms of purified 65-kDa protein was recovered from 5 x 10(8) PBMC. Analysis of the amino-terminal sequence of the purified pp 65 revealed the amino terminus of pp 65 to be blocked. Amino acid sequence analysis of a cyanogen bromide cleaved peptide showed pp 65 to be a unique protein whose protein sequence has not yet been reported. Studies of the distribution of p(p) 65 based on Western blotting using specific polyclonal rabbit antibody to p(p) 65 showed that p(p) 65 exists in a variety of cells such as neutrophils, monocytes, B lymphocytes, and myeloid cells. It could not be detected in the T cell leukemia cell line (MOLT), melanoma cells, and fibroblasts.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Purification and characterization of a cytosolic 65-kilodalton phosphoprotein in human leukocytes whose phosphorylation is augmented by stimulation with interleukin 1. 326 3

Regiospecific syntheses of gamma- and alpha-conjugates of methotrexate and poly(L-lysine) are described. The alpha- and gamma-t-butyl esters, respectively, of methotrexate were coupled to poly(L-lysine) with diphenylphosphoryl azide in N,N-dimethylformamide, the ester-protecting group was cleaved with 15% hydrogen bromide in acetic acid, and small molecules were removed by dialysis. Poly(L-lysine) of Mr = 1,500-8,000 and 8,000-30,000 was used to prepare six different conjugates, which were characterized by ultraviolet absorbance measurement and quantitative amino acid analysis. The degree of substitution varied from one methotrexate per 4.7 lysines to one methotrexate per 10.2 lysines. Dihydrofolate reductase inhibition in a cell-free assay was observed with alpha- and gamma-conjugates, but the latter had the greater affinity (only 3-fold less than that of methotrexate itself). The binding of the conjugates exhibited a slight pH dependence, with affinity being greater at pH 7.2 than at pH 8.5 for both alpha- and gamma-conjugates. Toxicity to cultured rat hepatoma cells (H35) was also greater for the gamma-conjugates, and showed some dependence on the chain-length and degree of substitution of the poly(L-lysine) carrier. Cells resistant to methotrexate by virtue of a transport defect (H35R0.3 line) retained their sensitivity to the gamma-conjugate, but less so to the alpha-conjugate. There was also some retention of sensitivity in a more highly resistant cell line (H35R10) with impaired methotrexate transport and a concomitant increase in dihydrofolate reductase activity. gamma-Conjugation was likewise more favorable in cytotoxicity assays against L1210 murine leukemia cells, and there was partial retention of activity against highly methotrexate-resistant lines (L1210/R71 and L1210/R81) with a transport defect and/or an elevation of dihydrofolate reductase content. In antitumor assays against intraperitoneal L1210 leukemia in mice, a gamma-conjugate with Mr = 8,000-30,000 and one methotrexate per 5.5 lysines produced a 35-75% increase in lifespan when administered intraperitoneally at single doses equivalent to 10-20 mg/kg of methotrexate. A similar increase in lifespan with methotrexate alone on the single-dose regimen required 50-150 mg/kg. An alpha-conjugate of similar Mr and degree of substitution was inactive at nontoxic doses, as were other gamma-conjugates of lower Mr and/or degree of substitution.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Regiospecific gamma-conjugation of methotrexate to poly(L-lysine). Chemical and biological studies. 396 26

Murine peritoneal macrophages elicited by dimethyldioctadecylammonium bromide (DDA), which is a potent immunologic adjuvant, were examined for cytotoxic and growth inhibiting activity for malignant cells. DDA macrophages had no cytolytic activity for murine B16BL-6 melanoma or human SMS-SB pre-B leukemia cells even in the presence of up to 1 microgram bacterial endotoxin (lipopolysaccharide, LPS)/ml. However, they exhibited a variable inhibitory effect on the growth of several lines of leukemia cells. The number of SMS-SB and human NALL cells remained essentially static in the presence of DDA macrophages while they increased significantly when cultured with resident macrophages. In contrast, L1210 cells increased 5-8-fold in the presence of macrophages elicited either by DDA or the inflammatory agent proteose peptone (PP). Although DDA macrophages retarded L1210 growth relative to PP macrophages, both populations responded to LPS in a comparable dose dependent manner to become essentially cytostatic at 1 microgram LPS/ml.
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PMID:Effect of dimethyldioctadecylammonium bromide induced macrophages on malignant cell proliferation. 400 32

The kinetics of the reaction of a series of cis-platinum(II) compounds with DNA in vitro has been studied using their ability to disturb the secondary structure of the macromolecule. The complexation modifies the stacking of the base pairs and causes an inhibition of the intercalation of ethidium bromide which is correlated with the number of platinum atoms bound per nucleotide. The compounds fall into three groups which react in a few minutes, in a few hours or in several days. The inhibition of the complexation by chloride and carboxylato ions indicates that the interaction occurs through hydrolysed species and that hydrolysis is the rate limiting step. In addition the results indicate that the carboxylato entities are able to react with DNA in vitro without enzymatic activation and that there is no correlation between the antitumoral activity of these compounds against L1210 Leukemia cells and their in vitro reactivity towards DNA.
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PMID:Kinetics of the reaction of cis-platinum compounds with DNA in vitro. 407 75

The role of mitochondria in the reproduction of RNA-containing tumor viruses was examined by using ethidium bromide (EB) to induce degenerative effects in mitochondria. The effects of EB in murine and avian cells were monitored by electron microscopy. Chronically infected mouse (JLS-V5) cells, in which extensive mitochondrial changes were induced, continued to produce murine leukemia virus. Also, complete reproductive cycles of Rous sarcoma virus (RSV) occurred in newly infected chicken embryo cells exposed to EB. Morphological transformation characteristic of infection of chicken embryo cells by RSV occurred in cells which contained induced aberrant mitochondria. The results demonstrate that mitochondria play a relatively minor role, if any, in the reproduction of RNA-containing tumor viruses.
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PMID:Role of mitochondria in the production of RNA-containing tumor viruses. 434 31

Antibodies in sera from patients with adult T-cell leukemia-lymphoma or from healthy carriers of type I human T-cell leukemia virus (HTLV) recognize an antigen of approximately 42 kilodaltons (p42) in cell lines infected with HTLV-I. Radiolabel sequence analysis of cyanogen bromide fragments of p42 led to the conclusion that this antigen is encoded in part by LOR, a conserved portion of the "X" region that is flanked by the envelope gene and the 3' long terminal repeat of HTLV-I. It is possible that this novel product mediates the unique transformation properties of the HTLV family.
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PMID:Antigens encoded by the 3'-terminal region of human T-cell leukemia virus: evidence for a functional gene. 608 50

The effects of protein modification on the antigenic determinants of p30 and gp70 of type C retroviruses were investigated by using solid-phase competition radioimmunoassays. Proteins were modified by reduction with 2-mercaptoethanol and subsequent carboxymethylation of SH groups with iodoacetamide or by amidination of alpha and epsilon amino groups with methylacetimidate. The type-specific determinants of gp70 were found to be conformational in nature, as they were destroyed by these chemical modifications. Group- and interspecies-specific determinants of gp70 antigens, however, appear to be sequential and do not involve residues susceptible to these chemical reagents. Conformation-dependent type-specific determinants of p30 were affected only by methylacetimidate. Group- and interspecies-specific determinants of p30 are similar to those of gp70 in that they also appear to be sequential antigenic sites. Therefore, the broadly reactive group- and interspecies-specific determinants of gp70 and p30 can be followed into small peptides. Accordingly, a cyanogen bromide cleavage fragment derived from the carboxyl-terminal one-third of Rauscher leukemia virus p30 was found to carry group-specific determinants but no detectable interspecies-specific determinants. In contrast, a peptide obtained by limited trypsin cleavage of p30, which was derived from the NH(2)-terminal region of the protein, contained at least one of the interspecies determinants shared with feline leukemia virus p27.
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PMID:Effect of chemical modification and fragmentation on antigenic determinants of internal protein p30 and surface glycoprotein gp70 of type C retroviruses. 615 54

Bleomycin is an anti-tumor agent whose cytotoxicity is related to the introduction of both single-stranded and double-stranded breaks in cellular DNA. In an assay using isolated nuclei, low levels of ethidium bromide substantially increased bleomycin induced release of nuclear chromatin. Treatment of mouse L1210 leukemia cells in vitro with low levels of ethidium bromide followed 1 hr later by bleomycin produced a synergistic effect that was 8 fold greater than that expected from the additive cytotoxicity of each drug alone. Interestingly, when the order of drug addition was reversed the drug synergism was much reduced (2 fold). The combination of DNA unwinding and strand scission agents may represent a novel and rational approach to the chemotherapy of cancer.
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PMID:Synergistic interactions of ethidium bromide and bleomycin on cellular DNA and growth inhibition. 620 Nov 71


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