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 developed a method for use in investigating factors controlling the binding and cross-linking by bivalent haptens of immunoglobulin E (IgE) bound to receptors on rat basophilic leukemia (RBL) cells. This method employs monoclonal anti-2,4-dinitrophenyl (DNP) IgE that is labeled with fluorescein-5-isothiocyanate (FITC), and it measures FITC quenching that accompanies DNP occupation of the antibody combining sites in a titration experiment. The validity of this approach is demonstrated using the monovalent hapten DNP-L-lysine. The affinity constant for this ligand obtained by the FITC quenching method is compared with those obtained with previously established methods: equilibrium dialysis and quenching of endogenous tryptophan for IgE in solution and [3H]-DNP-L-lysine binding to IgE on cells. The FITC quenching method has been used to carry out a detailed study of the binding of monovalent DNP-aminocapryol-L-tyrosine (DCT) and bivalent (DCT)2-cystine to FITC-IgE and its Fab fragments in solution. Intrinsic (K) and cross-linking (Kx) affinity constants are obtained by analyzing the binding curves in terms of simple equilibrium equations. With these DCT haptens the ability of this method to assess hapten binding and cross-linking of IgE bound to receptors on RBL cells is shown.
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PMID:Cross-linking of IgE-receptor complexes at the cell surface: a fluorescence method for studying the binding of monovalent and bivalent haptens to IgE. 294 10

Several human cells were investigated for their ability to degrade tryptophan and to synthesize neopterin upon induction by interferon-gamma (500 units/ml for 48 h). Concentrations of tryptophan, kynurenine, 3-hydroxykynurenine, anthranilic acid, 3-hydroxyanthranilic acid, 7,8-dihydroneopterin and neopterin were assessed in the culture supernatants by HPLC. Fibroblasts, A-22 arachnoidea, HK-2351 scalp, T-2346 meningeom and HeLa cervical carcinoma cells but not HL-60 promyelocytic leukaemia cells were found to degrade tryptophan upon induction by interferon-gamma. Tryptophan is converted to kynurenine by fibroblasts, A-22 arachnoidea and HK-2351 scalp cells and to kynurenine and anthranilic acid by HeLa cervical carcinoma and T-2346 meningeom cells. Kynurenine and anthranilic acid always make up more than 82% of the tryptophan degraded. None of these cells synthesizes 3-hydroxyanthranilic acid, 3-hydroxykynurenine, 7,8-dihydroneopterin or neopterin. Human macrophages form 3-hydroxyanthranilic acid and neopterin, but not 3-hydroxykynurenine, beside kynurenine and anthranilic acid upon activation by interferon-gamma. These data indicate that several human cells can be induced by interferon-gamma to degrade tryptophan. The interferon-gamma induced synthesis of 3-hydroxyanthranilic acid and neopterin, however, appears to be restricted to human macrophages. A hypothesis explaining these findings is presented.
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PMID:Interferon-gamma-induced degradation of tryptophan by human cells in vitro. 312 84

Two proteins, termed gp60 and p30, have been purified to homogeneity from bovine leukemia virus (BLV) using controlled pore glass and reverse-phase liquid chromatography (RPLC). gp60 was shown to be a glycoprotein by identification of glucosamine on the amino acid analyzer. Antiserum prepared to gp60 recognized in addition to gp60 a 52,000-Da polypeptide in some virus preparations, but did not cross-react with p30. The amino and carboxyl termini of gp60 were found to be tryptophan and arginine, respectively, and a 38-residue amino-terminal sequence of gp60 (NH2TrpArgXSerLeuSerLeuGlyAsnGlnGlnTrpMetThrAlaTyrAsnGlnGluAlaLys PheSerIleSerIleAspGlnIleLeuGluAlaHisAsnGlnSerProPhe-) was obtained. A 12-residue amino-terminal sequence for p30 (NH2SerProValAlaAlaLeuThrLeuGlySerAlaLeu) was also obtained. The p30 sequence showed substantial homology to the transmembrane proteins of both types B and C retroviruses and also to a deduced sequence of the 3' region of the env gene of human T-cell leukemia virus. From these results and from elution behavior of these proteins on RPLC, it was concluded that gp60 and p30 are the BLV env gene-encoded surface glycoprotein and transmembrane protein, respectively.
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PMID:The envelope proteins of bovine leukemia virus: purification and sequence analysis. 620 44

Intermediate metabolites of tryptophan, 3-hydroxy-L-kynurenine (3-OHKY), 3-hydroxyanthranilic acid (3-OHAA) and anthranilic acid (AA), and an enzyme inhibitor from 3-OHKY to 3-OHAA, isonicotinic acid hydrazide (INH) with or without 3-OHKY at the maximum tolerated dose were injected s.c. to infant CDF1 mice. AA and 3-OHAA were tested transplacentally for tumorigenicity. Animals treated were observed for 1 year. Hepatocellular adenoma was developed at the incidence of 21.7% in male mice administered with 3-OHKY and INH as compared with 5.6% incidence in control males, but no leukemia was induced. Incidences of lung (3.4--15.0%) and liver tumors (4--5%) in other groups treated at infant stage were comparable to that in controls (lung: 11.1%; liver: 5.6%). Other tumors were one angiogenic sarcoma in a female treated with 3-OHAA, and one granulosa cell tumor of ovary in female treated with INH. Transplacentally the 10.3% incidence of liver tumor in male offspring, whose mothers were treated with AA, was slightly higher than that in male control (5.6%). However, the incidences of tumor were apparently in a critical level in these experimental conditions.
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PMID:Comparative study of tumorigenicity in mice administered transplacentally or neonatally with metabolites of tryptophan and its related compounds. 624 61

The complete amino acid sequence of glycoprotein gp71A of Friend murine leukemia virus (F-MuLV) is presented. The protein moiety of gp71A was digested with Staphylococcus aureus (SV8) protease, trypsin, and thermolysin. The sequences of the peptides were determined by the micro dansyl Edman procedure. gp71A is composed of 445 amino acid residues and contains eight oligosaccharide side chains, which are attached exclusively to asparagine by N-glycosyl bonds primarily in the COOH-terminal half of the polypeptide. gp71A is rich in proline (49 residues), tryptophan (16 residues), and cysteine (19 residues). Proline has the highest molar content (11%) of all amino acids. The prolines cluster in two segments. The most interesting one stretches between residue 233 and residue 283 and contains 18 prolines within 51 amino acids. This proline-rich domain most likely forms a flexible polyproline helix. The comparison of gp70 of Moloney murine leukemia virus (Mo-MuLV gp70) with F-MuLV gp71A revealed that 70 amino acids have been exchanged and 9 residues have been deleted from Mo-MuLV gp70. The most striking alterations have taken place within the large polyproline segment (residues 247 to 281). In this part of the molecule 7 amino acids have been deleted in Mo-MuLV and 18 residues have been replaced. This evidence supports the proposal of Shinnick et al. [Shinnick, T. M., Lerner, R. A. & Sutcliffe, J. G. (1981) Nature (London) 293, 543-548] that this area is a "hot spot" for recombination.
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PMID:Complete amino acid sequence and glycosylation sites of glycoprotein gp71A of Friend murine leukemia virus. 631 May 44

Central nervous system regulation of endocrine functions is mediated by neurotransmitters, via hypothalamic hypophysiotropic factors which in turn control anterior pituitary functions. The evidence of serotonergic-endocrine interrelations with regard to adrenal, thyroid, gonadal and prolactin functions is fast accumulating. Our study extends the importance of those interrelations to some functions of the immune system. Multiple administration of 5-hydroxytryptamine(serotonin) or its precursor, 5-hydroxy-L-tryptophan(5-HTPH), produces marked depression of T cell dependent, humoral, hemolytic, primary immune response in mice. L-tryptophan, a more distant serotonin precursor, produces slight but significant depression of this immune response. Multiple treatment of mice infected with Friend Leukemia Virus (FLV) with serotonin or 5-HTPH alone or in combination with cyclophosphamide (Cytoxan) results in significant delay of the clinical progression of the infection. L-tryptophan produces a modest but significant improvement. Administration of serotonin or 5-HTPH causes a marked reduction of the thymus weight. It is reasonable to postulate that the described effects result from the thymus involution which affects the T cell compartment of the immune system. This is the consequence of hormonal imbalance caused by the alteration of the serotonin biosynthetic pathway in the brain. The adrenal cortex is not implicated in the mediation of this effect. Since many clinically used drugs affect the serotonin metabolism, the clinical consequences of the resulting alteration of the immunological responsiveness should be considered.
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PMID:Serotonin and its precursors as modulators of the immunological responsiveness in mice. 696 31

Using modified nuclear lysis and binding conditions, we have examined the binding of an embryonal carcinoma (EC) cell factor, binding factor A, to a stem cell-specific silencer which acts at the DNA level and overlaps the Moloney murine leukemia virus (M-MuLV) proline primer binding site (PBS). Following our protocol, we found that in vitro binding of factor A correlated with the in vivo activity of the M-MuLV silencer. Factor A bound specifically to the wild-type silencer element at room temperature and 30 degrees C, but not at 4 degrees C, and bound 10-fold better to the full-length silencer than to a minimal silencer core element. The factor was enriched in nuclear compared with cytosolic extracts and in undifferentiated EC cells compared with differentiated cells in which the silencer is nonfunctional. Salt and ion requirements for factor A binding were investigated, and partial purification steps indicated the factor to be a heparin-Sepharose-binding moiety of greater than 100 kDa. To examine possible relationships between silencer and PBS activities, sequences representing phenylalanine, isoleucine, lysine-1,2, lysine-3, methionine, and tryptophan PBS DNA fragments were tested in vivo for stem cell-specific repression of M-MuLV expression and in vitro in DNA binding assays. Of these PBS elements, only the lysine-1,2 PBS DNA fragment showed consistently high levels of repression. Interestingly, the lysine-1,2 PBS DNA fragment also formed a complex with an EC cell factor with characteristics similar to those of factor A. However, the two factors did not cross-compete in binding studies, suggesting that they may be different but related factors. Our results suggest that expression of Mason-Pfizer monkey virus, visna virus, and spumavirus, which use the lysine-1,2 PBS, may be inhibited in undifferentiated stem cells.
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PMID:Stem cell factor binding to retrovirus primer binding site silencers. 752 29

Methylamine dehydrogenase, a tryptophan tryptophyl quinone (TTQ) containing quinoprotein, catalyzes the oxidation of a variety of primary aliphatic monomaines and diamines to their respective aldehydes and ammonia. This paper reports the construction and characterization of an enzyme electrode capable of detecting histamine and methylamine at +200 mV versus a saturated calomel reference electrode. The methylamine dehydrogenase isolated from Paracoccus denitrificans was used in conjunction with the insoluble mediator tetracyanoquinodimethane (TCNQ) to construct enzyme electrodes which will potentially provide simple rapid analysis of histamine without the need for the extensive sample pretreatments currently required in HPLC and GLC analysis. The linear response of this amperometric sensor, between 0 and 200 microM, correlates well with elevated histamine levels predominant in patients with chronic myelogenous leukaemia, whilst the observed limit of detection, 4.8 microM, compares favourably with the lower limits of detection reported for a potentiometric histamine sensitive enzyme electrode.
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PMID:Amperometric detection of histamine at a quinoprotein dehydrogenase enzyme electrode. 761 8

TR1.3 is a Friend-related murine leukemia virus that has been shown to cause intracerebral hemorrhages and neurologic disease due to infection and subsequent cytopathology of cerebral vessel endothelium. A striking feature of this pathology is the formation of endothelial cell syncytia. The pathogenesis of this disease has now been mapped to a single amino acid substitution of tryptophan to glycine in the variable region of the envelope protein. This same mutation enabled TR1.3 to form syncytia and retard cell proliferation in vitro in the SC-1 mouse embryoblast line but did not affect the pH dependence of viral entry. These results demonstrate that subtle molecular changes in retroviral env genes can induce both syncytium formation and overt clinical disease.
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PMID:A point mutation in the env gene of a murine leukemia virus induces syncytium formation and neurologic disease. 793 35

This study was designed to clarify the important association between eosinophilia-myalgia syndrome (EMS) and the L-tryptophan contaminant, "Peak E." To determine the functional activation of eosinophils induced by Peak E, eosinophil cationic protein (ECP) release was examined. Peak E augumented the release of ECP from peripheral blood normodense eosinophils by degranulation. Proliferative analysis using the human eosinophilic leukemia cell line EoL-3 showed prominent cellular replication in the presence of Peak E. Moreover, Peak E upregulated interleukin 5 (IL-5) receptor levels on normodense eosinophils. Of particular interest, Peak E-stimulated human splenic T cells produced bioactive and immunoreactive IL-5. Marked induction of IL-5 mRNA in Peak E-stimulated T cells was also shown by reverse-transcriptase polymerase chain reaction (RT-PCR). In contrast, L-tryptophan without the contaminant showed none of these effects. Thus, these data suggest that Peak E might be involved in the pathogenesis of EMS through bimodal mechanism including IL-5 generation by T cells and potentiation of eosinophil functional activation.
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PMID:1,1'-Ethylidenebis(tryptophan) (Peak E) induces functional activation of human eosinophils and interleukin 5 production from T lymphocytes: association of eosinophilia-myalgia syndrome with a L-tryptophan contaminant. 813 37


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