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

All chemicals, even water and salt, can cause toxic effects if they are given to humans or laboratory animals in high enough doses. Similarly, the incidences of various kinds of neoplasm may be increased non-specifically in animals by the administration of innocent chemicals by an inappropriate route or in doses that are excessive enough to disturb normal nutritional, or hormonal status or interfere with mineral balance. High dietary concentrations of sorbitol or xylitol, if fed to laboratory rats cause enlargement of the caecum, increased absorption of calcium from the gut, increased urinary excretion of calcium, pelvic and corticomedullary nephrocalcinosis, acute tubular nephropathy, urinary calculus formation and both hyperplasia and neoplasia of the adrenal medulla. High dietary concentrations of lactose give rise to a similar spectrum of effects when given in excessive dosage to laboratory rats. Recent evidence suggesting that in the rat, but not in the mouse or in man, excessive calcium absorption stimulates the adrenal medulla is reviewed. In the mouse, but not in the rat or in man, a biologically significant amount of glycolic acid, which is a minor metabolite of xylitol in all three species, is converted to oxalate which then appears in the urine. Although the increase in urinary oxalate in the mouse is only about 20% of normal, this is enough in animals fed on diets containing 10% or 20% xylitol to predispose to bladder stone formation, and the prolonged presence of stones in the bladders, particularly of mice, in turn, predisposes to bladder tumour development. Neither bladder stones nor bladder tumours are seen in rats because biologically significant conversion of glycolate to oxalate does not occur. Studies in humans exposed up to 1 g/xylitol/kg body weight/day have revealed no evidence of increased urinary oxalate excretion. It is concluded that both the bladder tumours seen in mice, in response to 10% or 20% xylitol in the diet, and the adrenal tumours seen in rats, in response to 20% sorbitol or 20% xylitol in the diet, are laboratory artefacts. In other words, humans exposed to "normal" levels of these agents would be at no risk of developing either of these kinds of neoplasm.
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PMID:Perspectives in carbohydrate toxicology with special reference to carcinogenicity. 659 75

Among skin extracts of various frogs, lectin activity was found only in fractions prepared from Xenopus laevis skin. 3 skin lectins have been separated. Among these, the lectin designated S2-Dlc was isolated in a homogeneous state and showed a preferential agglutination of Ehrlich and S-180 ascites tumor cells; other tumor cells and human erythrocytes were not agglutinated. The lectin-dependent agglutination was inhibited by D-fucose, L-arabinose, D-galactose, lactose and lactulose. The sugar specificity of this lectin is similar to that of the lectin from Xenopus laevis eggs which agglutinates Ehrlich and S-180 ascites cells.
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PMID:Studies on three kinds of lectins from Xenopus laevis skin. 674

The effects of different agars (Bacto-agar and deoxycholate lactose agar), agaroses (LE, ME, Sea Plaque and Sea Prep 15/45) and methyl cellulose on the growth of a human tumor cell line, derived from a transitional cell carcinoma of the urinary bladder, were examined. The overall growth in the presence of agars and agarose was generally less than in liquid medium alone. In contrast, growth in the presence of methyl cellulose was significantly enhanced. Thus, methyl cellulose may be a useful agent for optimizing the proliferation of primary tissue cultures prepared from human transitional cell carcinomas.
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PMID:The effect of different agars, agaroses and methyl cellulose on the in vitro proliferation of a human urinary transitional cell carcinoma cell line. 685 12

Human tumor cell lines, derived from cancers of the colon, ovary, and cervix, were grown in liquid tissue culture media and media made semisolid with agar (Bacto + deoxycholate lactose agar), agarose [LE, ME, Sea Plaque and Sea Prep (15/45)], and methyl cellulose. The effects of each agent on overall cell proliferation and rate of overall cell proliferation were examined. The agents, used to make media semisolid, were observed to inhibit or, in some cases, enhance cell growth in a fashion that was characteristic of individual cell lines. These phenomena may be of consequence to the optimization of nutrient media for primary tumor cell preparations.
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PMID:The proliferation of human tumor cell lines in the presence of different agars, agaroses, and methyl cellulose. 687 74

To determine whether lactose malabsorption can be induced in children receiving cancer chemotherapy, lactose breath hydrogen tests (LBHT) were performed on 27 patients (ages 2 months to 16 10/12 years, mean 4 3/12 years) with neoplastic disease. Nine patients had an LBHT before their first course of chemotherapy and then 7--26 days afterwards. Eighteen other patients, less than 5 years old and presumed by virtue of age to be normal lactose absorbers, had an LBHT 7--24 days after their last course of chemotherapy. All nine in the first group had a normal LBHT before chemotherapy, and three had an abnormal LBHT 7--21 days later. Six of eighteen patients in the second group had an abnormal LBHT. Of the nine patients with an abnormal LBHT, six had a history of diarrhea associated with chemotherapy. These findings have important implications for children receiving cancer chemotherapy. High-calorie, milk-containing solutions used in nutritional support may precipitate cramps and diarrhea in some of these patients. A therapeutic trial of a low lactose diet in children in whom diarrhea develops during chemotherapy may be indicated.
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PMID:Cancer chemotherapy-induced lactose malabsorption in children. 705 78

Monoclonal antibodies were prepared against the trisaccharide Gal alpha 1-3Gal beta 1-4GlcNAc, a sequence which occurs on the surface of Ehrlich ascites tumor cells as well as in thyroglobulin, laminin and a variety of other proteins. This was accomplished by immunizing BALB/c mice with the fraction of Ehrlich cell membrane glycoproteins obtained by affinity chromatography on a Griffonia simplicifolia I (GS I) column which selectively binds alpha-D-galactosyl-terminated structures. Detection of Gal alpha 1-3Gal beta 1-4GlcNAc-specific antibodies was accomplished by employing glycoproteins containing the trisaccharide sequence; fusion with spleen cells from an immunized mouse was accomplished in the presence of polyethylene glycol (PEG1500). An enzyme-linked immunosorbent assay (ELISA) system was used to identify two clones (2.10G and 6.8E), which recognized the desired trisaccharide conjugate. These clones also recognized a thyroglobulin fraction isolated by GS I affinity chromatography and murine laminin, both of which possess the Gal alpha 1-3Gal beta 1-4GlcNAc sequence. Inhibition of antibody-trisaccharide reactivity, examined employing an ELISA assay, revealed that two trisaccharides, Gal alpha 1-3Gal beta 1-4GlcNAc/Glc, were the best inhibitory haptens; Gal beta 1-4GlcNAc (LacNAc), Gal alpha 1-3Gal and Gal beta 1-4Glc (lactose) were poor inhibitors. Indirect immunofluorescence staining of unfixed Ehrlich cells using the monoclonal antibody at 4 degrees C revealed fluorescence over the entire cell surface. Indirect immunogold labeling of semithin and ultrathin sections of aldehyde fixed and Lowicryl K4M-embedded Ehrlich cells resulted in specific labeling of the cell surface and internal structure.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Monoclonal antibodies that recognize the trisaccharide epitope Gal alpha 1-3Gal beta 1-4GlcNAc present on Ehrlich tumor cell membrane glycoproteins. 750 69

The sequence in the assembly of the functional unit of selectin ligands containing sulfate, sialic acid, and fucose and also tumor-associated O-glycan structures was studied by examining the specificities of alpha 2,3-sialyltransferases (ST). The first enzyme, porcine liver ST, was 57, 37, and 79% active (Km: 0.105, 0.420, and 0.200 mM), respectively, toward 6-sulfo, 6-sialyl, or 6-O-methyl derivatives of the Gal beta 1,3GalNAc alpha- unit; C-3 or C-6 substitution on Gal abolished sialylation. An acrylamide copolymer (MW approximately 40,000) containing approximately 40 T-haptens and asialo Cowper's gland mucin (MW approximately 200,000) containing approximately 48 T-haptens was 5-fold more active as an acceptor as compared to Gal beta 1, 3GalNAc alpha-O-Al on a molecular weight basis. The second enzyme, a cloned alpha-2,3-ST specific for lactose-based structure, was 70, 102, and 108% active (Km: 0.500, 0.210, and 0.330 mM), respectively, toward 6-sialyl, 6-sulfo, or 6-O-methyl derivatives of the Gal beta 1,3GlcNAc beta- unit; C-3 and C-6 substitution on Gal abolished sialylation. Gal beta 1,4GlcNAc beta- and its 6-sulfo derivative were approximately 20% active; the Lewis a structure, Gal beta 1,3- (Fuc alpha 1,4)GlcNAc beta-, was not an acceptor. The acrylamide copolymers containing approximately 40 units of Gal beta 1,3GlcNAc beta-, Gal beta 1,3(6-sulfo)GlcNAc beta-, or fetuin triantennary asialo or bovine IgG diantennary glycopeptides were respectively 5.9-, 5.4-, 0.7-, and 0.1-fold as active. A transfer of 7-9 mol of NeuAc per mole of the above copolymers was catalyzed by this ST, the sialyl linkage being susceptible to alpha 2,3-specific sialidase. A partially purified Colo 205 Lewis type (alpha 1, 3/4) fucosyltransferase catalyzed the formation of 3'-sialyl-6-sulfo Lewis a from [9-3H]NeuAc alpha 2, 3Gal beta 1, 3(6-sulfo)GlcNAc beta-O-Allyl and copolymer containing [9-3H]NeuAc alpha 2, 3Gal beta 1, 3(6-sulfo)GlcNAc beta- units, using GDP[14C]Fuc as fucosyl donor. The third enzyme, HL-60 ST, was 103% active with Gal beta 3(6-sulfo)GalNAc alpha- but was only 8% active with 6-sialo compound; it showed 11.6-fold greater activity with the copolymer of T-hapten. Further, we observed the alpha 2,3 sialylation of Gal beta 1,4GlcNAc beta- but not Gal beta 1,3GlcNAc beta- by HL60-ST, consistent with the occurrence of 3'-sialyl LacNAc and 3'-sialyl Lewis x units in leukosialin of HL60.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Selectin ligands and tumor-associated carbohydrate structures: specificities of alpha 2,3-sialyltransferases in the assembly of 3'-sialyl-6-sialyl/sulfo Lewis a and x, 3'-sialyl-6'-sulfo Lewis x, and 3'-sialyl-6-sialyl/sulfo blood group T-hapten. 753 77

Recognition of the carbohydrate part of cellular glycoconjugates by sugar receptors like lectins may contribute to biosignaling and interactions between normal and transformed cells. Such recognitions may be essential for establishing phenotypic characteristics in neoplastic cells, including metastasis-associated properties. To evaluate various glycoconjugates in tumor diagnosis and clinical therapy, a panel of 18 biotinylated neoglycoproteins was prepared. This included conjugates of a histochemically inert carrier protein and crucial sugar moieties such as D-glucuronic acid, alpha- and beta-N-acetyl-galactosamine, beta-N-acetyl-glucosamine, melibiose, lactose, maltose, cellobiose, mannose, mannose-6-phosphate, fucose, rhamnose, and xylose. In so doing the diazo derivative of the respective p-aminophenyl glycosides was coupled with galactose, beta-N-acetyl-galactosamine or beta-N-acetyl-glucosamine via an epoxy group-containing aliphatic spacer. Other glycoconjugates used were the proteoglycan heparin and the sulfated fucan fucoidan. Labeling was effected with cyanogen bromide activation and aminoalkylation for specific detection of endogeneous sugar receptors, especially lectins. Tissues studied were paraformaldehyde-fixed, paraffin-embedded surgical biopsies from patients with different stages of squamous cell carcinomas (SCCs) of the oral cavity (n = 16) and oropharynx (n = 17), including three lymph node metastases from oropharyngeal primary tumors. Semiquantitative binding differences of probes to tumor stages were evaluated statistically by the Mann-Whitney U-Wilcoxon rank sum W test. Specific binding of a probe to cytoplasmic and nuclear structures was detected with apparent quantitative differences. Overall, the cytoplasmic compartment revealed a higher intensity of histochemical reaction than did nuclear structures, indicating a comparatively higher density of specific carbohydrate receptors.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Characterization of sugar receptor expression by neoglycoproteins in oral and oropharyngeal squamous cell carcinomas. 757 87

Blood group H type 1 [Fuc alpha (1,2)Gal beta (1,3)GlcNAc beta-->] is known as the precursor structure of the blood group determinant, Lewis b [Fuc alpha (1,2)Gal beta (1,3)(Fuc alpha (1,4))GlcNAc beta-->]. Recently, a new biosynthetic route for Lewis b from Lewis a [Gal beta (1,3)(Fuc alpha (1,4))GlcNAc-->] was identified in human gastric carcinoma cells, colon carcinoma Colo 205, and ovarian tumor. The present study demonstrates the association of this new type of alpha (1,2)-L-fucosyltransferase (FT) activity with the Lewis-type alpha (1,3/4)-L-FT as follows: (i) the alpha (1,4)- and novel alpha (1,2)-FT activities of Colo 205 were much less inhibited than the alpha (1,3)-FT activity by N-ethylmaleimide [Ki(microM) = 714.0, 119.0, and 6.5 respectively]. (ii) The alpha (1,4)- and novel alpha (1,2)-FT activities emerged from a Sephacryl S-200 column in identical positions. (iii) A specific inhibitor (copolymer from 3-sulfo-Galbeta(1,3)GlcNAcbeta-O-allyl and acrylamide) of alpha(1,4)-FT activity inhibited both alpha(1,4)- and alpha(1,2)-FT activities in Sephacryl S-200 column effluent to almost the same extent (approximately 80%); (iv) separation of the Lewis-type alpha(1,3/4)-FT from the plasma-type alpha(1,3)-FT by specific elution of the affinity column (bovine IgG glycopep-Sepharose) with lactose and further purification on a Sephacryl S-100 HR column showed that (a) the alpha(1,3)-FT activity was the inherent capacity of the Lewis-type FT (Colo 205 fraction L) since approximately 90% of both the alpha(1,4)- and alpha(1,3)-FT activities is inhibited by the copolymer, (b) the unique ability of catalyzing the alpha(1,2)-L-fucosylation of Gal in Lewis a structure and also the alpha(1,3)-L-fucosylation of Glc in lactose-based structure belonged to the Lewis type enzyme (Colo 205 fraction L), (c) a measurement of the [14C]fucosyl products arising from the two acceptors Galbeta(1,3)(4,6-di-O-Me)GlcNAcbeta-O-Bn and 3-sulfo-Galbeta(1,3)GlcNAcbeta-O-A1 (specific for alpha(1,2) and alpha(1,4), respectively) taken in the same incubation mixture showed mutual inhibition by the acceptors ([Km for the alpha(1,4)-specific acceptor, 3-sulfo-Galbeta(1,3)GlcNAcbeta-O-A], increased from 32 to 50 microM in the presence of 7.5 mM Galbeta(1,3)(4,6-di-O-Me)GlcNAcbeta-O-Bn, whereas Ki for the mutual inhibition of alpha(1,2)-FT activity by the former was 102 microM], and (d) the Lewis-type FT, in contrast to the plasma type FT, was highly effective in fucosylating complex glycopeptides. (iv) A cloned FT (FT III:Lewis type) and the Colo 205 Lewis-type FT (fraction L) showed similar activities toward various acceptors; the enzymatic product resulting from the action of cloned FT on Galbeta(1,3)(Fucalpha(1,4))GlcNAc-beta-O-Bn was identified by FAB mass spectrometry as the difucosyl compound. (v) An examination of six human cell lines indicated that the novel alpha(1,2)-FT activity associates with the alpha(1,4)-FT activity.
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PMID:Expression of blood group Lewis b determinant from Lewis a: association of this novel alpha (1,2)-L-fucosylating activity with the Lewis type alpha (1,3/4)-L-fucosyltransferase. 771 81

We estimated the levels of free sialic acid and sialylated oligosaccharides excreted in the urine of normal donors (n = 10) and patients with gastric cancer (n = 6) and colorectal cancer (n = 4). The total sialic acid level in cancer patients was similar to that in normal donors. However, the ratios of glycosidically bound sialic acids to free sialic acid were higher in some advanced cancer patients than in the normal donors. A major component of sialylated oligosaccharides was N-acetylneuraminyl alpha (2-->3) lactose. The elevation of the urinary ratio of this sialylated oligosaccharide to free sialic acid observed in some advanced cancer patients in this study may reflect the elevation of sialyltransferase activity in tumor tissues.
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PMID:Elevation of ratio of urinary N-acetylneuraminlactose to free sialic acid in some advanced cancer patients. 771 10


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