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Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An alpha-fucosyltransferase activity has been demonstrated in rat ascites hepatoma AH 7974F cells catalyzing the transfer of L-fucose to asialo-GM1 prepared from bovine brain GM1 ganglioside to form a fucolipid in the presence of Triton X-100. The radioactive fucolipid was shown to be Fuc-(alpha1 leads to 2)-Gal-(beta1 leads to 3)-GalNAc-(beta1 leads to 4)-Gal-(beta1 leads to 4)-Glc-ceramide from the following results. The radioactive product coincided with authentic blood group H-active fucolipid from AH 7974F cell on thin-layer chromatography. The product formed a precipitation line not only with Ulex europeus lectin but also with eel anti-H serum on agarose gel plates. The terminal 14C-labeled fucose was released by Bacillus fulminans alpha(1 leads to 2)fucosidase as well as Charonia lampas alpha-fucosidase. The optimum pH value for the incorporation of L-fucose into asialo-GM1 was 5.8 in cacodylate/HCl buffer. The fucosyltransferase was highly specific for asialo-GM1.
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PMID:Enzymic synthesis of a new type of fucose-containing glycolipid with fucosyltransferase of rat ascites hepatoma cell, AH 7974F. 3 11

Lectins, plant proteins that bind specific saccharide determinants, have been utilized to examine the effect of neuraminidase digestion on the structure and/or expression of oligosaccharide moieties present at the periphery of Novikoff ascites hepatoma cells. Five lectins were utilized: concanavalin A (Con A), specific for alpha-D-manno- or alpha-D-glucopyranosyl residues; wheat germ agglutinin, specific for 2-acetamido-2-deoxy-D-glucopyranosyl residues; Ricinus communis agglutinin I (RCAI), specific for D-glucopyranosyl residues; R. communis agglutinin II (RCAII), specific for D-galacto- or 2-acetamido-2-deoxy-D-galactopyranosyl residues; and soybean agglutinin, specific for 2-acetamido-2-deoxy-D-galactopyranosyl residues. Neuraminidase treatment of Novikoff cells did not alter their agglutination by Con A or wheat germ agglutinin. Similar treatment produced only a 2-fold increase in their agglutination by RCAI but a 12-fold increase in their agglutination by RCAII, indicating that 2-acetamido-2-deoxy-D-galactopyranosyl residues become expressed upon neuraminidase treatment. This conclusion was confirmed by the observation that neuraminidase-treated Novikoff cells acquired agglutinability by soybean agglutinin. Binding studies using ferritin-conjugated RCAII indicated that neuraminidase treatment exposed cryptic cell surface receptors for RCAII. To ascertain the role of cell surface glycoproteins in lectin-induced agglutination of Novikoff cells, glycopeptides cleaved from the cell surface by papain were assayed for lectin receptor activity. The cell surface glycopeptides exhibited receptor activity for Con A, wheat germ agglutinin and RCAI but not for RCAII and soybean agglutinin. A cell surface macrosialoglycopeptide fraction, resolved by gel filtration and ion-exchange chromatography, possessed a major portion of the Con A and RCAI receptor activity.
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PMID:Effect of neuraminidase and papain treatment on lectin-induced agglutination of Novikoff tumor cells and assay of lectin receptor activity of the glycopeptides released from the cell surface by papain. 17 11

Membrane glycoprotein biosynthesis of ascites hepatoma cells is followed by [14C]glucosamine and [3H]leucine incorporation into cells in culture. The rate of incorporation is strongly increased by the addition of Robinia lectin in culture medium. Labeled glycoproteins are released from lectin stimulated and non-stimulated cells by trypsin digestion. Studies of labeled trypsinates on sodium dodecyl sulfate gel electrophoresis and Sephadex G-200 filtration exhibit two fractions both labeled with [14C]glucosamine and [3H]leucine and having different molecular weights, one over 200000 and the other about 2000. Identical results are obtained when external membrane glycoproteins are solubilized by sodium deoxycholate. Comparison of surface glycoproteins isolated by trypsinization from control cells labeled with [3H]-glucosamine and from lectin stimulated cells labeled with [14C]glucosamine displays no significant qualitative differences between glycoprotein fractions released from both cell groups.
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PMID:Stimulation of the biosynthesis of membrane glycoproteins from Zajdela ascites hepatoma cells by Robinia lectin. 18 23

tRNAAsp from rabbit liver, rat liver and rat ascites hepatoma was readily isolated by concanavalin A-Sepharose (Con A-Sepharose) affinity column chromatography. tRNATyr from these sources was extensively purified by Ricinus communis lectin-Sepharose column chromatography. These results, together with the chromatographic behaviour of four tRNAs (tRNATyr, tRNAHis, tRNAAsn and tRNAAsp) on acetylated DBAE-cellulose column chromatography suggested that tRNAAsp contains a Q nucleoside species having a mannose moiety while tRNATyr contains Q nucleoside with galactose. The sugars attached in 4-position of cyclopentene diol in the Q molecule are therefore not present at random in the four tRNAs, but present only in each specific tRNA. This is the first case which shows that plant agglutinin interacts with nucleic Acid as well as polysaccharide and glycoproteins.
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PMID:Isolation of mammalian tRNAAsp and tRNATyr by lectin-Sepharose affinity column chromatography. 19 May 93

The fate of lectin labeled internalized plasma membrane in the ascites tumor form of the Chang rat hepatoma growing under in vivo and in vitro conditions was investigated cytochemically. Ascites cells were incubated in Convanavalin A (Con A) and horseradish peroxidase (PO), either with or without prior glutaraldehyde fixation and subsequently treated with 3',3-diaminobenzidine. In cells fixed before Con-A-PO labeling the reaction product was localized as a continuous and even layer upon the external surface of the plasma membrane. If unfixed cells were treated with Con A, coupled with PO at 4 degrees C and reincubated in phosphate buffered saline at 37 degrees C for varying periods of time, the Con-A-PO layer was of irregular thickness. In as little as 15 min of reincubation endocytotic vesicles containing PO positive material were closely associated with GERL components of the Golgi Apparatus. Localization of acid phosphatase (ACPase) within GERL vesicles, similar in size and location to those containing Con-A-PO reaction product, indicates that the Con-A-PO labeled vesicles may be a component of the Golgi apparatus in hepatoma cells.
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PMID:Cytochemical localization of lectin labeled vesicles in GERL region of hepatoma ascites cells. 38 67

The presence of glycopeptide lectin receptors in the ascitic fluid of rats bearing Novikoff or AS-30D hepatoma was investigated. Macrosialoglycopeptides, resistant to pronase digestion, were partially purified from the ascitic fluid of hepatoma-bearing rats by gel filtration on Sephadex G-50. A macrosialoglycopeptide fraction, isolated from the ascitic fluid of rats bearing the Novikoff hepatoma, possessed potent concanavalin A (Con A) receptor activity. This fraction possessed higher Con A receptor activity than did the comparable macrosialoglycopeptide fraction from the ascitic fluid of rats bearing the AS-30D hepatoma; this obeservation is in agreement with the Con A-induced agglutination properties of these 2 hepatoma cell lines and with the Con A receptor activities of the glycopeptides released from the surface of the hepatoma cells by papain digestion. Rat blood serum contained a comparable macrosialoglycopeptide fraction, which possessed weak Con A receptor activity. The macrosialoglycopeptide fractions from the ascitic fluid of hepatoma-bearing rats possessed wheat germ agglutinin receptor activity. However, this activity was also present in normal rat serum. These results suggest that glycopeptides present on the surface of Novikoff hepatoma cells are shed into the ascitic fluid and may be distinguished from components in normal serum by their Con A receptor activity.
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PMID:Concanavalin A and wheat germ agglutinin receptors in the ascitic fluid of rat hepatomas. 44 22

Purified guinea pig basophils, or basophils either specifically degranulated with antigen or nonspecifically degranulated with lectin, were cultured with guinea pig line 1 hepatoma cells for 1 to 24 hr and studied ultrastructurally. As early as 1 hr of culture, degranulated or nongranulated basophils and tumor cells formed close contacts by mutually intertwined elongated cell processes and also in cultures containing degranulated basophils, extruded membrane-free basophil cytoplasmic granules became firmly attached to tumor cells. At later intervals, some tumor cells cultured with basophils exhibited cytostatic and cytopathic changes, including dense mitochondria, centralization of organelles, dilated perinuclear and rough endoplasmic cisternae, cell swelling and cytoplasmic lucency, disrupted cytoplasmic organelle and plasma membranes, nuclear pyknosis and fragmentation. Some tumor cell specialized surface attachments were either disrupted or damaged at points of basophil or basophil granule adhesion. Tumor damage was most extensive in cultures containing degranulated basophils, although only a minority of tumor cells (less than 10%) was affected. Tumor injury was seen much less frequently in the presence of nondegranulated basophils, and was absent in control cultures of tumor alone. The occasional viable tumor cells that phagocytosed basophil granules were apparently unharmed, suggesting that internalization of basophil granules by tumor cells is not cytotoxic.
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PMID:Tumor-basophil interactions in vitro--a scanning and transmission electron microscopic study. 44 31

1. Plasma membranes isolated from rat livers and ascites hepatoma cells (AH-130, AH-7974) were assayed for specific Ca2+ binding sites using 45Ca2+ and a Millipore filtration technique. The presence of higher (Kd = 1.4--1.5 . 10(-5) M) and lower (Kd = 0.9--1.0 . 10(-4) M) affinity sites in both liver and hepatoma membranes was observed. The hepatoma plasma membranes however, showed 1.4--2.1-fold as many Ca2+ binding sites (higher and lower affinity sites) as the liver plasma membranes on the basis of protein. 2. Concanavalin A stimulated the specific Ca2+ binding to liver and hepatoma plasma membranes, showing a maximal stimulation (3--5-fold) at 100 microgram/ml. Succinyl concanavalin A was less effective, whereas wheat germ agglutinin and ricinus lectin were ineffective. 3. Concanavalin A stimulated the Ca2+ uptake by AH-7974 cells. The concanavalin A-mediated stimulation of Ca2+ uptake showed lectin-concentrations and Ca2+-concentration dependencies similar to those in the concanavalin A-mediated stimulation of Ca2+ binding.
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PMID:Ca2+ binding sites in plasma membranes of rat liver and hepatoma cells, and effect of concanavalin A on the Ca2+ binding sites and cellular uptake of Ca2+. 50 44

1 The incorporation of [3H]-thymidine into guinea-pig lymphocytes stimulated by a plant lectin (concanavalin A), soluble antigen (tuberculin (P.P.D.)) and syngeneic hepatoma cells, was partially inhibited (50%) by histamine in vitro. 2 The effect of histamine on both mitogen and antigen dose-response curves suggests a non-competitive, probably physiological antagonism. 3 The inhibitory dose range of histamine lay between 10 nM and 30 microM with an ID50 of approximately 400 nM. 4 The potency order for histamine analogues for the inhibition of lymphocyte activation was histamine greater than or equal to 4-methylhistamine greater than 2-methylhistamine greater than 3-methylhistamine. This is in accord with the mediation of the response through an H2-receptor. 5 H2-receptor antagonists reversed the inhibitory effect of histamine in a dose-related manner, but both metiamide and burimamide, in high concentrations, augmented lymphocyte activation in their own right. This precluded the determination of affinity constants and made it impossible to state with certainty that the inhibition of lymphocyte activation by histamine was mediated by an H2-receptor.
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PMID:Inhibition of guinea-pig lymphocyte activation by histamine and histamine analogues. 52 5

The distribution of the Lens culinaris lectin receptors on normal rat liver cells, on rat liver cells in vivo transformed by diethylnitrosamine and on Zajdela ascites hepatoma cells of the rat is investigated by means of the Lens culinaris lectin-peroxidase method and by ferritin conjugated Lens culinaris lectin. The normal rat liver cells show a continuous labeling at the outer membrane surface by the lectin complexes, whereas the transformed rat liver cells exhibit a strong tendency for patchy distribution of the cell surface label. The discontinuous cell surface label in the transformed rat liver cells is obviously caused by an internalization of plasma membrane areas. The importance of these morphological findings in their relationship to Lens culinaris lectin mediated agglutination of rat liver cells and the membrane fluidity in general are discussed. In the experiments no hints to a rotation of the Lens culinaris lectin receptors from the outer membrane surface to the inner membrane surface of rat liver cells can be found.
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PMID:Lens culinaris lectin receptors in the plasma membrane of rat liver cells: comparative electron microscopic studies on normal cells, on cells in vivo transformed by diethylnitrosamine and on Zajdela ascites hepatoma cells. 123 3


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