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)

Acivicin is an investigational amino acid antitumor antibiotic currently being evaluated in Phase II clinical trials. In humans acivicin causes reversible, dose-limiting central nervous system (CNS) effects including somnolence, ataxia, personality changes, and hallucinations. We have observed and reported previously that acivicin-treated cats exhibit symptoms (ataxia, sedation, somnolence) resembling CNS toxicity reported in humans. We hypothesized that if acivicin uptake into brain were mediated by a saturable transport system common to endogenous amino acids, drug uptake and CNS toxicity might be blocked by elevation of normal amino acid concentrations in circulating plasma. To test this hypothesis, cats received constant-rate i.v. infusions of either saline or Aminosyn, 10% (a commercially available mixture of 16 amino acids not containing glutamine, glutamate, aspartate, or cysteine) for 4 h prior to and 18 h subsequent to administration of acivicin at a dose producing marked behavioral changes in control cats. Presence or absence of ataxia and sedation were noted at intervals after acivicin treatment. Results showed that Aminosyn infusion prevented CNS symptoms in six of eight cats. Subsequent experiments showed that acivicin levels in brain tissue of Aminosyn-treated cats were 13% of the drug levels in saline-infused cats. Acivicin levels in most peripheral tissues were also decreased significantly by Aminosyn infusion but not to the extent observed in brain. Decreased brain uptake was shown to be due to a combination of amino acid blockade of drug transport into that organ and of increased total body clearance of drug. Concomitant Aminosyn treatment did not alter the efficacy of acivicin in mice bearing L1210 leukemia or MX-1 human mammary carcinoma. Further studies demonstrated that a solution containing only four large neutral amino acids (leucine, isoleucine, phenylalanine, and valine) could also protect cats from acivicin-induced CNS toxicity, apparently without increasing acivicin total body clearance. However, a mixture of several other amino acids contained in Aminosyn (alanine, arginine, tyrosine, histidine, proline, serine, and glycine) failed to prevent CNS toxicity. We conclude that cotreatment with Aminosyn or a mixture of large neutral amino acids could protect cancer patients from acivicin-induced CNS toxicity without ablating antitumor efficacy.
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PMID:Prevention of central nervous system toxicity of the antitumor antibiotic acivicin by concomitant infusion of an amino acid mixture. 238 52

The NH2-terminal amino acid sequence of Moloney murine leukemia virus reverse transcriptase was determined to be Thr-Leu-Asn-Ile-Glu-Asp-Glu-Tyr-Arg-Leu-His-Glu-. The comparison of the amino acid analysis data obtained after carboxypeptidase Y digestion with the published nucleotide sequence (T. M. Shinnick, R. A. Lerner, and J. G. Sutcliffe, Nature (London) 293, 543-548, 1981) led to the conclusion that the COOH-terminus is Leu coded by CTC in nucleotide positions 4608-4610, and the tentative COOH-terminal sequence is Pro-Asp-Thr-Ser-Thr-Leu-Leu-OH. In light of these and previously reported results the complexity and map order of the pol gene are discussed.
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PMID:Amino- and carboxyl-terminal sequence of Moloney murine leukemia virus reverse transcriptase. 241 14

The replication of Moloney murine leukemia virus (MMuLV) in chronically infected mouse cells arrested at the G0/G1 phase of the cell cycle by different procedures was investigated. MMuLV production was inhibited in glutamine- and isoleucine (Gln-Ile)-deprived G0/G1 cells. In contrast, butyric acid treatment, which efficiently arrested the cells at the G0/G1 phase of the cell cycle, did not inhibit MMuLV production. Furthermore, the inhibition of MMuLV production caused by either Gln-Ile deprivation or by interferon (IFN) treatment was overcome by butyric acid treatment. Thus, the replication of MMuLV could be dissociated from cell proliferation. The inhibition of MMuLV production in Gln-Ile-deprived cell cultures was compared to the inhibitory effect of IFN, which is known to affect budding and release of the virus. Rates of MMuLV protein synthesis were not affected in both the IFN-treated and Gln-Ile-deprived cells. However, processing of the viral polyprotein Pre65gag into p30 was blocked in the Gln-Ile-deprived cells. Furthermore, whereas in IFN-treated cells, MMuLV accumulated on the cell surface and could be released upon treatment with trypsin, in Gln-Ile-deprived cells, no virions were released by such treatment. These results indicate that in cells arrested by Gln-Ile deprivation, MMuLV is inhibited at a posttranslation step. This step appears to precede the anti-MMuLV block induced by IFN.
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PMID:Regulation of Moloney murine leukemia virus replication in chronically infected cells arrested at the G0/G1 phase. 258 48

A large scale production of human recombinant IL-5 (hIL-5) was performed by way of recombinant DNA technology. In this study, we transfected Chinese hamster ovary cells with pdKCR-hIL-5gene-dhfr plasmid and selected a cell line, with the use of methotrexate, producing large amounts of hIL-5. The recombinant hIL-5 thus obtained induced IgM production of murine B cell leukemia BCL1, and its activity was inhibited by TB13 anti-mouse IL-5 monoclonal antibody. hIL-5 could be purified from the cell-free supernatants of the transfectants with high recoveries by using anti-mouse IL-5 antibody-coupled immunoaffinity column in combination with a gel permeation column chromatography. N terminal amino acid sequence analysis of purified hIL-5 revealed that a single amino-terminal amino acid (isoleucine) is detected and hIL-5 consists of 115 amino acid residues.
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PMID:Rapid methods for purification of human recombinant interleukin-5 (IL-5) using the anti-murine IL-5 antibody-coupled immunoaffinity column. 260 55

The envelope glycoproteins of the human immunodeficiency virus (HIV) type 1 are synthesized as a precursor molecule, gp160, which is cleaved to generate the two mature envelope glycoproteins, gp120 and gp41. The cleavage reaction, which is mediated by a host protease, occurs at a sequence highly conserved in retroviral envelope glycoprotein precursors. We have investigated the sequence requirements for this cleavage reaction by introducing four single-amino-acid changes into the glutamic acid-lysine-arginine sequence immediately amino terminal to the site of cleavage. We have also examined the effects of these mutations on the syncytium formation induced by HIV envelope glycoproteins. Our results indicate that a glutamic acid to glycine change at gp120 amino acid 516, a lysine to isoleucine change at amino acid 517, and an arginine to lysine change at amino acid 518 affect neither gp160 cleavage nor syncytium formation. The results obtained with the arginine to lysine change at amino acid 518 differ significantly from the results obtained with the same mutation at the envelope precursor cleavage site of a murine leukemia virus (E. O. Freed, and R. Risser, J. Virol. 61:2852-2856, 1987). An arginine to threonine mutation at gp120 amino acid 518, the terminal residue of gp120, abolishes both gp160 cleavage and syncytium formation. These findings demonstrate that despite its highly conserved nature, the basic pair of amino acids at the site of gp160 cleavage is not absolutely required for proper envelope glycoprotein processing. This report also supports the idea that cleavage of gp160 is required for activation of the HIV envelope fusion function.
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PMID:Mutational analysis of the cleavage sequence of the human immunodeficiency virus type 1 envelope glycoprotein precursor gp160. 267

The production of Moloney murine leukaemia virus from chronically infected cells was inhibited after starvation of glutamine. While the rate of synthesis of the precursor of the core proteins, Pr65gag, was not affected in the starved cells, its proteolytic processing was blocked. Pulse-chase experiments indicated that glutamine was required during the synthesis of Pr65gag to facilitate its subsequent processing. In addition, the synthesis of Pr200gag-pol, the precursor of the protease, reverse transcriptase and endonuclease, was inhibited in the glutamine-starved cells. Starvation for other essential amino acids such as tyrosine and isoleucine affected neither the synthesis nor the processing of the virus proteins. These results suggest that the readthrough mechanism which enables synthesis of the Pr200gag-pol polyprotein is modulated in the chronically infected cells by glutamine levels. Since the viral protease is part of the pol gene, its synthesis may be inhibited in the glutamine-starved cells and Pr65gag is therefore not processed.
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PMID:Glutamine starvation of murine leukaemia virus-infected cells inhibits the readthrough of the gag-pol genes and proteolytic processing of the gag polyprotein. 348 14

The hemoglobins synthesized by the pluripotent K-562 leukemia cell line of human origin after induction with hemin have been isolated by DEAE-cellulose chromatography and characterized by electrophoresis, high pressure liquid chromatography, and a radioimmunological assay. Six hemoglobin zones have been observed with the following likely compositions. Zone 1: alpha 2 epsilon 2, or HB Gower-2; zone 2: zeta 2 epsilon 2, or HB Gower-1; zone 3: zeta 2 gamma 2, or HB Portland-I; zone 4: Hb F, or alpha 2 gamma 2; zone 5: a mixture of acetylated HB Portland-I and Hb F; zone 6: Hb Bart's, or gamma 4. The embryonic Hbs (zones 1, 2, and 3) constituted 50%-75% of the total Hb present; the quantities varied from one experiment to the other. Both Hb Gower-1 and Hb Gower-2 were present. The gamma chain was heterogeneous and contained the G gamma, A gamma I, and A gamma T types in a ratio of about 4:2:1, indicating a heterozygosity for the Ile leads to Thr substitution at position gamma 75. The methodology used can be applied for additional studies evaluating quantitative changes in Hb types due to in vitro manipulations.
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PMID:Identification and quantitation of embryonic and three types of fetal hemoglobin produced on induction of the human pluripotent leukemia cell line K-562 with hemin. 617 8

Previously, in vitro recombinant DNA studies demonstrated that genetic determinants of N-tropism and B-tropism, or Fv-1-related host range properties of murine leukemia viruses, were located in a BamHI-HindIII DNA segment derived from the 5' portion of the cloned viral genome. We sequenced this segment and its immediate 5' region from cloned DNA of two BALB/c mouse C-type viruses (WN1802N and WN1802B) and found base differences at 12 positions out of the otherwise identical 1,390-base-pair sequences. Analysis of the most likely reading frame showed that 6 of the 12 base differences would result in four encoded amino acid changes, three of which occur at positions 109 (glutamine in WN1802N versus threonine in WN1802B), 110 (arginine in WN1802N versus glutamic acid in WN1802B), and 159 (glutamic acid in WN1802N versus glycine in WN1802B) of the p30 protein. The remaining one is located at position 36 (threonine in WN1802N versus isoleucine in WN1802B) of the viral polymerase protein. Significant conformational alteration of the p30 protein could be predicted from these amino acid changes.
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PMID:Nucleotide sequences of gag-pol regions that determine the Fv-1 host range property of BALB/c N-tropic and B-tropic murine leukemia viruses. 631 71

The antineoplastic activity of 7 ester derivatives and 15 amide derivatives of N-[N'-(2-chloroethyl)-N'-nitrosocarbamoyl (CNC)]-aminoacids was examined in transplanted rat leukemia L 5222. All esters except the ethylester of CNC-L-isoleucine showed only a moderate antitumor activity. CNC-L-isoleucine ethylester effected some cures and showed the lowest toxicity of this series of compounds. The amide derivatives on the other hand were highly active in L 5222; all compounds effected cures in the dose range investigated.
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PMID:Antineoplastic activity of esters and amides of N-[N'-(2-chloroethyl)-N'-nitrosocarbamoyl]-aminoacids. 647 33

Restriction of phenylalanine to 0.08%, or less, of the diet has been shown to prolong the survival of L1210 leukemia-bearing DBA/2Ha mice or (DBA/2Ha female X BALB/c male) F1 hybrids. A clonal assay was developed for determining the infiltration of L1210 cells without adaption to cell culture. Phenylalanine restriction significantly reduced at the infiltration of IP implanted tumors in tissues of minimal tumor involvement, such as bone marrow and brain. These tumor reductions did not occur with dietary limitations of isoleucine, leucine, cystine-methionine or protein. Tumor infiltration rose to control levels when phenylalanine-limited hosts were immunosuppressed with whole body irradiation or with cyclophosphamide. The L1210-responding BALB/c host when phenylalanine-restricted required a 2- to 3-fold increase in dosage of whole body irradiation in order to succumb to the tumor. In vitro complement-dependent and -independent cytotoxicity of the splenocytes of several host strains immunized to both L1210 cells and sheep erythrocytes were, however, generally reduced by phenylalanine depletion. Phenylalanine depletion is postulated to favor the development of an unidentified immunoproductive and radiation-resistant component of host tumor response.
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PMID:Improved host defense against L1210 leukemia by deprivation of dietary phenylalanine. 734 95


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