Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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

Pure ferritin from male mouse liver produces a single band of monomers (RF = 0.199) with electrophoresis in polyacrylamide gels at pH 9.0. The five sub-bands within this monomeric band appear to represent charge isomers having the same molecular size. Ferritin from BH3 transplantable mouse hepatoma shows two overlapping bands of monomers (RFA = 0.208 and RFB = 0.240); further electrophoretic studies show that these bands represent two subpopulations of molecules differing both in charge and size. Sub-bands are not found in this hepatoma ferritin. The larger tumor ferritin reaches the same end migration position as all liver isoferritins on gradient gels, signifying a very similar or identical molecular size; however, the absence of sub-bands indicates that this hepatoma ferritin differs in charge from the homologous liver proteins. Liver and hepatoma ferritins both produce a single prominent subunit band corresponding to nominal molecular weights of 22 250 and 21 700, with polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and dithiothreitol. With electrophoresis on polyacrylamide gradient slabs containing sodium dodecyl sulfate and dithiothreitol, both liver and hepatoma ferritins now reveal two subunits bands situated at identical positions. The polypeptides of these two closely spaced bands have a nominal molecular weight difference of less than 1000. Neither the hepatoma nor the liver seems to produce the ferritins found in the other tissue. Nevertheless, all these ferritins are composed of the same two types of subunits, albeit in different relative amounts. Observed distinctions in the ferritins from these normal or neoplastic cells must reflect differences in assembly and processing, as well as in the regulated expression of the same ferritin genes.
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PMID:Mouse hepatoma and liver ferritins. Comparative structural studies. 46 27

The effects of various agents on the binding and degradation of 125I-labelled insulin by isolated rat hepatocytes and cultured H4 hepatoma cells were studied. Various lysosomotropic agents, including chloroquine, ammonium chloride, and the topical anesthetics, lidocaine and procaine inhibited insulin degradation by H4 hepatoma cells but had little effect on the binding of the hormone. Similarly, tosyl-L-lysyl chloromethyl ketone selectively inhibited the degradation of 125I-labelled insulin by isolated hepatocytes, as did the sulfhydryl reagents, p-hydroxy- and p-chloromercuriphenyl sulfonic acid. Inhibitors of energy production, including sodium fluoride, sodium azide, and dinitrophenol, also selectively inhibited the degradation of insulin by hepatocytes, although cyanide had no effect under the conditions used. Lectins and antimicrotubular agents, which are known to affect the mobility of plasma membrane proteins or of intracytoplasmic vesicles, selectively inhibited insulin degradation by hepatocytes to varying degrees, whereas agents which inhibit the function of microfilaments had no effect. At temperatures below 20 degrees C, insulin degradation was negligible but rose rapidly between 20 and 37 degrees C, suggesting that a membrane-related step is rate limiting in the overall degradative process. These results are all consistent with a model of insulin uptake by target tissue involving pinocytosis of receptor-bound hormone followed by intralysosomal degradation.
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PMID:Mode of uptake and degradation of 125I-labelled insulin by isolated hepatocytes and H4 hepatoma cells. 47 1

Novikoff hepatocellular carcinoma cells were radioiodinated by a cell surface-specific method using lactoperoxidase/125I. The iodinated proteins were solubilized in 0.5% Nonidet P-40 and subjected to affinity chromatography on Sepharose-conjugated lectins (Ricinus communis agglutinins I or II, soybean agglutinin, concanavalin A, or wheat germ agglutinin) and analyzed by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Almost all the iodinated proteins bound to one or more of the Sepharose-conjugated lectins, presumptive evidence that these peptides are glycosylated. Lectin affinity chromatography resolved defined subsets of iodinated glycoproteins and suggested that certain glycoproteins could be fractionated on the basis of heterogeneity of their heterosaccharide moieties. Incubation of the iodinated cells with neuraminidase resulted in increased binding of iodinated proteins to Sepharose-conjugated Ricinus communis agglutinins I and II and soybean agglutinin and decreased binding to Sepharose-conjugated wheat germ agglutinin. Binding of iodinated proteins to concanavalin A was unaffected by neuraminidase treatment of the cells. These studies demonstrate the utility of lectins for the multicomponent analysis of plasma membrane proteins.
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PMID:Lectin affinity chromatography of cell surface proteins of Novikoff tumor cells. 54 27

Induction of DNA synthesis is associated with increased uptake of calcium in cultured cells. Calcium distribution within the plasma membrane and adjacent cytoplasmic layers of hepatoma cells was investigated with X-ray photoelectron spectroscopy and oxygen plasma etching. Cells in minimal growth medium initiate active DNA synthesis 16 h after addition of sodium pyruvate. Cells stimulated with pyruvate and pyruvate-free controls were analysed by X-ray photoelectron spectroscopy--oxygen plasma etching at 0--40 A (layer I), 0--450 A (layer II) and 0--4000 A (layer III from the outer cell surface. Calcium concentrations were elevated in induced cells compared with controls: +20% in layer I, +60% in layer II, and +300% in layer III. As the plasma membrane is 90--120 A thick, these results indicate that pyruvate-induced DNA synthesis is preceded by an increase in calcium, most marked in the cytoplasm subjacent to the plasma membrane, moderate at its inner surface, and minimal at its outer surface.
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PMID:Surface analysis and depth profiles of calcium in hepatoma cells during pyruvate-induced DNA synthesis. 56 45

We examined the ability of NaCl (at 0.15 to 3 M) to release non-histone proteins from chromatin of cultured rat hepatoma cells. The percentage of the non-histones released increased with increasing NaCl concentrations up to 0.75 M; 1 and 3 M NaCl were not significantly more effective. A maximum of 50% of the non-histone protein was recovered free of DNA. The release of non-histones from sheared and unsheared chromatin was similar. The electrophoretic patterns of the non-histone proteins released by NaCl resembled that of the non-histones released by sodium dodecyl sulfate, which indicates that many of the detectable components were at least partially released by NaCl. Some non-histones (especially low molecular weight polypeptides) were fully released by NaCl and other proteins were relatively resistant to NaCl release. Higher recoveries of NaCl-dissociated non-histones were obtained with sucrose gradient centrifugation than with centrifugation in the absence of sucrose.
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PMID:Analysis of the effectiveness of sodium chloride in dissociating non-histone chromatin proteins of cultured hepatoma cells. 57 60

The suitability for field use of heating up to 80 degrees C and adding six different virucidal chemicals for decontamination of drinking and surface water was investigated using the viruses of Polio (vaccine strain), ECBO, Reo, bovine Parvo, HCC, Pseudorabies, ND and Vaccinia. The Parvovirus (concentration 10(5) TCID50/ml) heated to 80 degrees C could not be inactivated completely in drinking water within one hour; the Reovirus could after one hour only at 60 degrees C. The other viruses used lost their infectivity at 56 degrees C within 60 minutes or at 60 degrees C within 20 minutes respectively. Heating therefore seems to be too circumstantial a method for viral decontamination of water and unreliable under field conditions. As to the chemical water additives tested, chloramine-T, hydrogen peroxide and sodium peroxide proved to be unsuitable in spite of virucidal activity. The amount of their concentration necessary for reliable virus inactivation makes the water unfit for drinking. Iodine, a calcium hypochlorite sample and potassium permanganate were useful. Because of its constant reaction in drinking water together with additional advantages, iodination of water would seem to be the best method at present for viral water decontamination usable under field conditions.
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PMID:[Studies on inactivation of viruses in drinking and surface water. A contribution to the decontamination of water by field methods (author's transl)]. 61 Feb 55

Buoyant-density centrifugation of unfixed chromatin has been performed in a newly devised medium containing 3-iodo-1,2-propanediol and metrizamide. Chromatins were obtained from isotopically labeled mouse hepatoma cells in suspension culture, either grown normally or density labeled in a medium containing bromodeoxyuridine, by mild digestion of isolated nuclei with micrococcal nuclease. When a mixture of normal and density labeled chromatin, marked with [14C]thymidine and [3H]bromodeoxyuridine, respectively, was centrifuged in the medium, chromatin peaks represented by labeled DNA were resolved to the extent expected from their separate banding profiles. Centrifugation of an equivalent chromatin mixture labeled with [14C] and [3H]lysine, respectively, also yielded resolution of chromatin peaks represented by labeled proteins. Only small amounts of labeled proteins were dissociated from chromatin in the gradient medium. Labeled proteins recovered from the gradient fractions were analyzed by electrophoresis on sodium dodecyl sulfate-polyacrylamide gels. The results suggested that most of the histones remained associated with the original stretches of DNA during the centrifual fractionation period. Essentially all of the dissociated proteins were found to be non-histone proteins.
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PMID:Fractionation of unfixed chromatin by buoyant-density centrifugation in gradients containing 3-iodo-1,2-propanediol and metrizamide. 64 Oct 28

Deoxyribonucleic acid polymerase-beta (EC 2.7.7.7) has been purified over 100 000-fold from a whole cell extract of guinea pig liver. The enzyme yields a single stainable band when subjected to non-denaturing polyacrylamide gel electrophoresis, and this band corresponds to the DNA polymerase activity when a sister gel is sliced and assayed. The final fraction has a specific activity of 21 000 units/mg; this value can be increased significantly by addition of various components, including glycols, polyamines or any of several protein factors which can be purified from the crude extract. The DNA polymerase-beta lacks detectable exonuclease or endonuclease activity, has an alkaline pH optimum and has a requirement for all four deoxyribonucleoside triphosphates, a divalent cation and a primer-template for maximal activity. While activated DNA is the preferred primer-template, the enzyme is capable of utilizing native and denatured DNA as well as several synthetic polynucleotides as primer-templates. The latter are especially effective when manganese is the divalent cation. Magnesium, at 10 mM, is the preferred divalent cation when activated DNA is used. Manganese, and to a lesser extent cobalt, can substitute for magnesium while zinc and calcium cannot. The beta-polymerase has a half-life of 10 min at 40 degrees C and this is increased in the presence of either DNA or NaCl. The enzyme is stimulated by glycols, polyamines and NaCal or KCl, and is inhibited by several known inhibitors of DNA polymerase activity including o-phenanthroline, heparin, organic solvents and sulfhydryl blocking agents. Guinea pig liver DNA polymerase-beta is remarkably similar to the rat Novikoff hepatoma beta-polymerase with respect to its isoelectric point of 8.4 and its molecular weight of 32 000 as determined by sucrose gradient centrifugation under high or low salt conditions or sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This similarity is further extended to the removal, at the final step in purification, of a protein capable of stimulating the homogeneous enzyme. Removal of this protein could explain the lower molecular weight of the guinea pig and other rodent-derived beta-polymerases, when compared to the beta-polymerases from other systems.
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PMID:Purification and properties of DNA polymerase-beta from guinea pig liver. 70 39

A Glycoprotein, particularly high in tumors, has been extracted from Morris 5123C rat hepatomas and purified. The compound constitutes a major binding component for 67Ga in this hepatoma. It has a molecular weight of approximately 45,000. Its molecular weight was determined by sodium dodecyl sulfate:polyacrylamide gel electrophoresis and by Sephadex G-200 superfine gel filtration. The steps involved in its extraction and purification include ultrafiltration, gel filtration through Sephadex G-200 superfine, ion-exchange chromatography on diethylaminoethyl Sephadex A-50, and hydroxylapatite chromatography. The homogeneity of the compound was established by gel electrophoresis. The NH2-terminal residue, the percentage of nitrogen, the nonamino carbohydrate content, and the amino acid composition are reported.
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PMID:Isolation and partial characterization of a 67Ga-binding glycoprotein from Morris 5123C rat hepatoma. 71 29

The messenger activity for fructose 1,6-bisphosphate aldolase (EC4.1.2.13) (aldolase) A isozyme has been characterized in the polysome- or the messenger RNA-directed, protein-synthesizing system using the pH 5 fraction of rat liver or wheat germ extracts, respectively. The subunit of aldolase A synthesized in vitro was detected by immunoprecipitation with anti-aldolase A antibody raised in chickens followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The synthesis of the enzyme depended on the addition of polysomes or polyadenylate-containing RNA of rat ascites hepatoma AH 7974 cells which show a complete shift of aldolase isozyme to type A, whereas polysomes of adult rat liver were inactive. The messenger activity for aldolase A was present exclusively on free polysomes but absent on membrane-bound polysomes and in the soluble supernatant fraction of AH 7974 cells. The size of aldolase A messenger RNA determined by formamide-containing sucrose density gradient centrifugation was approximately 5.8 X 10(5) daltons corresponding to 1650 nucleotides. Taking into account the number of amino acid residues in the aldolase A subunit, approximately 400 nucleotides correspond to the noncoding region of aldolase A messenger RNA.
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PMID:Characterization of messenger RNA for fructose 1,6-bisphosphate aldolase A isozyme of rat ascites hepatoma AH 7974 cells. 76 Dec 23


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