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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The use of Lens culinaris lectin for electron microscopic detection of D-mannose,- D-glucose and N-acetyl-D-glucosamine like sites on tumor cells, erythrocytes, erythrocyte ghosts, cultured rat liver cells and various tissues of mice is demonstrated. In addition to Lens culinaris lectin-peroxidase reaction (LeL-po reaction) the preparation of active Lens culinaris lectin-ferritin conjugate are described and the specificity of cytochemical reactions are demonstrated. Furthermore experiments by immuno freeze-etching are reported for topological analysis of the lectin receptors.
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PMID:Electron microscopic demonstration of cell surface carbohydrates by means of peroxidase and ferritin complexes of the Lens culinaris lection. 115 Apr 86

Three glycoprotein bands were identified by polyacrylamide disc gel electrophoresis in the perchloric acid soluble fraction of ascitic fluid of Ehrlich ascites tumor in mice. The three proteins were first separated by a new discontinuous preparative electrophoresis apparatus described previously [1]. They were further purified on Sephadex G-100 and then were subjected to chemical characterization. These glycoproteins were rich in glutamic and aspartic acids and contained the sugar moieties galactose, mannose, fucose, N-acetyl-D-glucosamine and sialic acid. The percent sugar composition ranged from 17.7-37.3% of the total weights of these glycoproteins.
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PMID:Glycoproteins from ascitic fluid of Ehrlich ascites tumor. Isolation and chemical characterization. 118 61

Following short-term suspension culture, cells from the Balb/C sarcoma Meth A were allowed to incorporate both [14C] leucine and 2-deoxy-D-glucose-1-[3H] (2DG). The 2DG is trapped as a small anionic marker of the cytosol. Deviation from the kinetics of spontaneous efflux of the markers is interpreted as reflecting perturbation of the target cell membrane. In the presence of guinea pig complement and a rabbit antiserum to Meth A, enhanced 2DG efflux was effected in a titer comparable to that detected with a 51Cr-release assay. With a number of alloantisera and syngeneic immune sera, 2DG efflux was enhanced while 51Cr-release was unaffected. Only in the presence of syngeneic immune sera from mice bearing a low tumor mass, syngeneic splenic leukocytes effect a retardation in the spontaneous 2DG efflux. Sera from animals with a large tumor mass were ineffective. Effux of proteins labeled with [14C] leucine was not altered. The phenomenon was not dependent on the presence of a heat-inactivatable syngeneic complement source. The method described provides a sensitive probe of target cell membrane permeability in the tumor model studied. The phenomenon detected is the capacity of serum, sampled relatively early in syngeneic oncogenesis, to direct syngeneic splenic leukocytes to interact with the target cell membrane differentially altering its permeability to the small cytosol marker.
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PMID:The use of 2-deoxy-D-glucose to assess changes in tumor target cell membranes in vitro. 120 22

Described are primary treatment protocols for 1) those patients with gorssly unresectable stage III or IV ovarian carcinoma, considered reasonable candidates for therapeutic trials aimed at the identification of antitumor activity as determined by the regression of objectively evaluable lesions; and 2) those patients with stage II or III ovarian carcinoma, with little or no visible tumor remaining after surgery, considered reasonable candidates for therapeutic trials involving regimens that may delay or prevent the recurrence of clinically apparent disease. Both protocol involve initially a comparison of cyclophosphamide alone with cyclophosphamide plus adriamycin. A third protocol--an activity-seeking study of two new cytotoxic agents, developed to provide secondary treatment opportunities for patients who have failed on one of the primary chemotherapy protocols--is designed to seek evidence of any cross-resistance between cytembena (beta-4-methoxybenzoyl beta-cis-bromacrylate) and VP-16 (4'-demethyl-epipodophyllotoxin-beta-D-ethylidene glucoside). Data from all three protocols are so far insufficient to allow meaningful analysis of their results.
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PMID:Status report of Mayo Clinic studies. 124 94

Currently available diagnostic tracers for brain tumors are not specific. Tumor-specific tracers would improve the detection of brain tumors by gamma encephalography. Glucose is an important substrate for tumor metabolism and is known to be taken up in large amounts. The authors have studied five labeled carbohydrates in an attempt to find a tumor-specific tracer: three were tritiated (L-galactose-1-3H, L-fucose-3H, and 4,6-dideoxy-xylo-hexose-3H) and two were radioiodinated (methyl-6-125I-6-deoxy-D-glucoside and 6-125I-6-deoxy-D-glucose). The uptake of these tracers by a transplantable mouse ependymoblastoma after intravenous injection was determined by liquid and well scintillation counting. The highest tumor-to-brain ratio was 7.1 to 1 for the tritiated tracers and 6.2 to 1 for the radioiodinated tracers. Although these ratios are not high enough for gamma encephalography, one of the iodinated tracers may be useful for enhancement of contrast in computerized axial tomography.
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PMID:Carbohydrates as potential diagnostic tracers for brain tumors. 127 Oct 88

Until five years ago, it was believed that the oligosaccharide chains of most, if not all, glycoproteins were assembled by the stepwise transfer of single sugar residues from their nucleotide derivatives to growing oligosaccharide chains attached to a polypeptide core. It is now becoming widely accepted that polyisoprenol-linked mono- and oligosaccharides function as activated glycosyl carriers in the biosynthesis of some glycoproteins in animal tissues. The lipophilic glycosyl carrier of monosaccharides is the phosphomonoester of dolichol, the C(80-100)-polyisoprenol, containing a saturated terminal isoprene unit. In this biosynthetic process, sugars are initially transferred to dolichol monophosphate from their nucleotide derivatives by membrane-associated glycosyltransferases. These dolichol-linked monosaccharides serve as glycosyl donors in the glycosylation of oligosaccharide phospholipids. It appears likely that dolichol is also the lipid moity of the oligosaccharide intermediates. Detailed enzymatic studies with oligosaccharide phospholipids formed by rat liver, a mouse myeloma tumor and hen oviduct have revealed that these intermediates function as oligosaccharide donors in the assembly of at least one class of glycoproteins. The exact nature of the glycoproteins glycosylated by lipid intermediates and the sub-cellular site(s) of this assembly process remain to be established. The possibility, that the mannose and GlcNAc-containing core found in many glycoproteins, is assembled at the lipid-level is now being investigated. At the current rate of progress in this area of research, the identity of the glycoproteins glycosylated via lipid intermediated and the subcellular site of this assmebly process will soon be known.
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PMID:Polyisoprenoid glycolipids involved in glycoprotein biosynthesis. 127 57

To determine whether incubation of mouse thyrotropic tissue with TRH in vitro influenced the oligosaccharide structure of TSH, thyrotropic tumor tissue or pituitary tissue was incubated in vitro with [3H]mannose or with [35S]sulfate and [3H]methionine, in the absence or presence of TRH for times up to 24 h. [3H]mannose-labeled oligosaccharides from intracellular TSH and free alpha-subunits were analyzed by paper chromatography, and were predominantly Man9GlcNAc and Man8GlcNAc units both in the absence and presence of TRH. The [35S]sulfate/[3H]methionine ratio in secreted molecules was greater for TSH than for free alpha-subunits; within TSH heterodimers the ratio was greater for beta-subunits than alpha-subunits. The [35S]/[3H] ratio was not altered in TSH or free alpha-subunits by TRH. Analyses of [3H]mannose-labeled charged oligosaccharides by HPLC anion-exchange chromatography revealed similar types of oligosaccharides present on TSH subunits and free alpha-subunits (having one or two sulfate residues, one or two sialic acid residues, or both a sulfate and a sialic acid residue). These charged oligosaccharides occurred in different proportions on TSH subunits compared to free alpha-subunits, and also differed depending on whether the tissue source was tumorous or nontumorous. The proportions of oligosaccharide unit types were not altered by TRH. Thus, while this study provided information concerning the high-mannose and complex oligosaccharides of mouse TSH, there was no evidence that short incubations of tissues with TRH in vitro caused modulation of TSH oligosaccharide structures.
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PMID:Structures of high-mannose and complex oligosaccharides of mouse TSH and free alpha-subunits after in vitro incubation of thyrotropic tissue with TRH. 128 Feb 15

Qualitative and quantitative changes in nuclear DNA and phenotypic expression of human malignant skin tumors were examined during the course of progression. The numerical abnormalities of chromosomes demonstrated by interphase cytogenetics using the chromosome-specific in situ hybridization technique, were also used to reveal qualitative DNA changes in malignant tumor cells. For the analysis of the quantitative changes in nuclear DNA, fluorescence cytophotometry was used on the DAPI-stained tumor cells isolated from the paraffin-embedded sections. To survey abnormal gene expression in malignant tumor cells, lectin histochemistry for different sugar residues, immunohistochemical staining of HLA-DR, and in situ hybridization for H-ras, c-myc, N-myc or v-fos were used. The results showed that: 1) in one case of squamous cell carcinoma with invasion, the number of chromosomal abnormalities was much greater in the invasive than in non-invasive parts, with marked topographical heterogeneities; 2) the DNA-ploidies were largely shifted to the higher side with aneuploid stem-lines and polyploid cells in the invasive parts of all malignant tumors; 3) the expression of HLA-DR was induced at the invasive fronts of malignant melanomas; 4) the GS-I specific sugar residue(D-galactose) appeared in all extra-mammary Paget's cells; and 5) expression of "oncogenes" was found in about 60% of all malignant tumors examined. Thus, the progression of malignancy is accompanied by both qualitative and quantitative changes in nuclear DNA, resulting in abnormal gene expression.
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PMID:Qualitative and quantitative changes in nuclear DNA and phenotypic gene expression in human malignant skin tumors during their progression. 128 Oct 11

To evaluate glucose metabolism in patients with tumors involving the liver, 35 patients with liver lesions had PET using 18F-2-fluoro-2-deoxy-D-glucose (FDG). FDG (148 MBq) was injected and radioactivity of the tumor was scanned dynamically by PET. The rate constants (k1, k2, k3, k4) of FDG in a metabolic model were calculated. The results were compared to hexokinase activity in the excised tumor specimens. k3 was found to reflect tumor hexokinase activity. When k3 was used as an index (cut-off value: 0.025), it was possible to distinguish benign and malignant tumors. k4 was significantly higher in hepatocellular carcinoma. By using k3 and k4 as indices, one could assess the degree of differentiation of hepatocellular carcinoma. After treatment, k3 decreased according to the effectiveness of therapy and thus may be a useful index for quantitatively assessing tumor viability.
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PMID:Evaluation of liver tumors using fluorine-18-fluorodeoxyglucose PET: characterization of tumor and assessment of effect of treatment. 174 Jun 99

The carbohydrate binding specificity of Mr = 30,000 lectin (CBP30) from baby hamster kidney (BHK) cells has been studied by inhibition of binding of the radiolabeled lectin to asialofetuin-Sepharose using model oligosaccharides and glycopeptides. CBP30 binds type I or II Gal beta(1----3(4))GlcNAc chains but not Gal(beta 1----3)GalNAc. The inhibitory potency of straight chain polylactosamine structures or complex-type branched glycans is increased in proportion to the number of Gal(beta 1----3(4)) units present. Fucosylation or sialylation of terminal galactose residues or further substitution by (alpha 1----3)-linked galactose or N-acetylgalactosamine does not affect binding whereas substitution of the penultimate N-acetylglucosamine residue drastically reduces binding. Thus, blood group A, H type I or H type II structures, shows high affinity whereas Lex, Lea, and Leb structures bind poorly. CBP30 binds to murine Engelbreth-Holm-Swarm (EHS) tumor laminin and human amniotic fluid fibronectin but not human plasma fibronectin. Binding involves polylactosamine glycans as well as tri- and tetraantennary complex-type glycans present in EHS laminin and amniotic fluid fibronectin but absent in plasma fibronectin. Proteolytic fragments of EHS laminin (E1X/Nd, P1, E8, and E3) bind CBP30, but only fragment E8 supports attachment and spreading of BHK cells. BHK cell adhesion to EHS laminin or fragment E8 was not disturbed by CBP30-specific antibodies, but at relatively high concentrations (45 micrograms/ml) CBP30 inhibited spreading and partially attachment of cells on laminin.
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PMID:Binding specificity of a baby hamster kidney lectin for H type I and II chains, polylactosamine glycans, and appropriately glycosylated forms of laminin and fibronectin. 131 27


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