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

Both the cells of monolayer culture of mouse embryonic liver and that of highly malignant hepatoma 22A transplanted for 20 years actively metabolized the carcinogenic hydrocarbon benz(a)pyrene and were highly sensitive to iits toxic action. Since hepatic tissue was resistant in vivo to carcinogenic carbohydrates it is suggested that the resistance depended on factors acting at the organ or the organism but not as the cellular level. The mechanism of retention of hepatoma 22A sensitivity to the toxic action of benz(a)pyrene is also discussed.
Biull Eksp Biol Med 1977 Sep
PMID:[Effect of benz(a)pyrene on a monolayer culture of normal and malignant mouse liver cells]. 19 94

The analogic liver scintigram using 99mTc sulfur colloid in cirrhotic patients does not permit determination of the nature of the areas of decreased uptake. Scintigrams with 67Ga citrate generally show increased activity in cases of hepatoma. In some cases, however, 67Ga citrate is less concentrated in neoplasic tissue, and it is not possible to detect a tumoral lesion in a cirrhotic liver. This is why we used double isotope scintigraphies with 67Ga citrate and 99mTc sulfur colloid, with digital subtraction, after simultaneous recording of 99mTc and 67Ga data on magnetic tape by means of an interface. In our series of 22 patients, the comparison of the results obtained by this double isotope technique with histology showed no false positive in substraction scintigrams. There was one false negative because of the lack of significance in the subtracted image for one of the six patients with cancer of the liver. For three of the six patients with hepatoma, the gallium scintigram showed an increased uptake in the tumor area. For the three other cases, the gallium uptake was equilibrated throughout the liver scintigraphy. It was therefore in cases where the gallium scintigram showed no increased activity that the subtraction technique was of greatest value, for it permitted the diagnosis of hepatoma in two cases.
Eur J Nucl Med 1977 Sep 30
PMID:Detection of hepatoma in liver cirrhosis. 19 43

Particles carrying heterogeneous nuclear RNA (30 S-particles) were prepared from rat liver and Zajdela hepatoma ascites cell nuclei after ultrasonic disruption. The ribonucleoprotein structures were disintegrated in the presence of 100mM spermidine. Using chromatography on Sepharose-polyadenylate a protein component has been obtained which possessed high affinity for heterogeneous nuclear RNA, polyuridylate and polyadenylate, and double-stranded DNA. This protein was the main species of the ribonucleoprotein studied; it showed bands with molcular weights of 37000 and 40000 respectively in SDS gel electrophoresis. The RNA-binding proteins isolated from liver and hepatoma had identical molecular weights and the same affinity for Sepharose-polyadenylate used in the isolation.
Mol Biol Rep 1977 Sep
PMID:Preparation in undenatured form of the main protein bound to heterogeneous nuclear RNA in liver and hepatoma cells. 19 32

Cultured rat hepatoma cells, H4-II-E-C3, are known to possess a phenylananine hydroxylating system which is sufficient to enable them to grow in tyrosine-depleted medium. Using standard procedures of auxotroph enrichment with this cell line, we have isolated tyrosine auxotrophs for the first time. We report in this paper the class of auxotrophs with (a) reduced (15-64% of wild type) or (b) absent activity of phenylalanine hydroxylase, an enzymic component of the phenylalanine hydroxylating system. This class of auxotroph presumably contains either lower (a) [or zero (b)] levels of normal phenylalanine hydroxylase protein than wild type, or mutant phenylalanine hydroxylase protein with lowered (or zero) activity. The two subgroups of auxotrophs (a) and (b) differ from each other in their revertibility and their growth behavior in the tyrosine-free medium. Over a 12-month period of testing, the auxotrophs have been highly stable with respect to their phenylalanine hydroxylase activity and growth phenotype in tyrosine-free medium. Such auxotrophs should facilitate genetic and biochemical study of the genes controlling the phenylalanine hydroxylation system and the study of phenylketonuria.
Somatic Cell Genet 1977 Sep
PMID:Genetics of the mammalian phenylalanine hydroxylase system: I. Isolation of phenylalanine hydroxylase-deficient tyrosine auxotrophs from rat hepatoma cells. 19 52

A case of metastatic malignant hepatoma in bone, developed in a Vietnamen woman, is reported. Indirect immunofluorescence and orcein staining detect HBs Ag in cytoplasm of many tumor cells. This finding raises pathogenic problems, in particular that of the responsability of heaptitis B virus in the aetiology of certain hepatic tumours.
Nouv Presse Med 1977 Sep 24
PMID:[Detection of HBs Ag in bone's metastatic malignant hepatoma (author's transl)]. 20 21

Conversion of glucose to fructose and sorbitol is documented in rat hepatoma-derived cultured cells (HTC cells). After addition of 5.5 mM [U-14C]glucose to incubation medium, labeled sorbitol and fructose accumulated intracellularly at a linear rate over a period of 60 min. The sugars were isolated, identified, and quantitated by paper chromatography, gas-liquid chromatography, and enzymatic phosphorylation of fructose. Primary culture of adult rat hepatocytes was analyzed similarly and demonstrated no significant accumulation of labeled fructose or sorbitol. The basis for this difference between HTC cells and primary hepatocyte culture was examined both in terms of enzyme activities that mediate the formation of sorbitol and fructose and in terms of the catabolism of these sugars. Both types of culture (as well as extracts of intact rat liver) exhibited enzymatic activities catalyzing the conversion of glucose to sorbitol (aldose reductase) and sorbitol to fructose (sorbitol dehydrogenase). However, the cultures differed strikingly with regard to the catabolism of sorbitol and fructose. The conversion of labeled sorbitol to metabolites in HTC cells was negligible; by contrast, hepatocytes in primary culture utilized the sugars at rates comparable to that of glucose, which may account for the lack of their accumulation in primary culture. The findings suggest that the conversion of glucose to sorbitol and fructose by HTC cells may represent a retained normal liver function, one which is amplified by the inability of HTC cells to dispose of these sugars.
J Biol Chem 1978 Sep 10
PMID:Conversion of glucose to sorbitol and fructose by liver-derived cells in culture. 21 Jan 65

Adenylate cyclase can be resolved into at least two proteins, a thermolabile, N-ethylmaleimide-sensitive component and a second protein (or proteins) that is more stable to either of these treatments. Neither component by itself catalyzes the formation of cyclic AMP using MgATP as substrate. However, mixture of the two reconstitutes MgATP-dependent fluoride- and guanyl-5'-yl imidodiphosphate (Gpp(NH)p)-stimulatable adenylate cyclase activity. The more stable component can be resolved from the first in various tissues or cultured cells by treatment of membrnes or detergent extracts with heat or N-ethylmaleimide. The two proteins have also been resolved genetically in two clonal cell lines that are deficient in adenylate cyclase activity. An adenylate cyclase-deficient variant of the S49 lymphoma cell (AC-) contains only the thermolabile activity, while the activity of the more stable protein is found in a complementary hepatoma cell line (HC-1). In addition, AC-S49 cell plasma membranes contain MnATP-dependent adenylate cyclase activity. The protein that catalyzes this reaction appears to be the same as that which can combine with the thermostable component to reconstitute Mg2+-dependent enzyme activity because both activities co-fractionate by gel exclusion chromatography and sucrose density gradient centrifugation, both activities have identical denaturation kinetics at 30 degrees C, and both activities are stabilized at 30 degrees C and labilized at 0 degree C by various nucleotides and divalent cations with similar specificity. It is thus hypothesized that the thermolabile factor is the catalytic subunit of the physiological adenylate cyclase and that the Mn2+-dependent activity is a nonphysiological expression of the catalytic protein. The thermostable moiety of the enzyme, which is proposed to serve a regulatory function, appears to consist of two functional components, based upon differential thermal lability of its ability to reconstitute hormone-, NaF-, or Gpp(NH)p-stimulated adenylate cyclase activity. These components have not, however, been physically separated. The thermolabile and thermostable components can interact in detergent solution or in a suitable membrane. Mixing of the detergent-solubilized regulatory component with AC-membranes that contain only the catalytic protein and beta-adrenergic receptors reconstitutes catecholamine-stimulatable adenylate cyclase activity; however, addition of the catalytic protein to membranes that contain receptor and the regulatory component yields MgATP-dependent enzymatic activity that is unresponsive to hormone.
J Biol Chem 1978 Sep 25
PMID:Reconstitution of hormone-sensitive adenylate cyclase activity with resolved components of the enzyme. 21 Jan 83

Phosphoprotein phosphatase which dephosphorylates 32P-labeled nucleolar protein substrates was found in nucleoli of Novikoff hepatoma ascites cells and normal rat liver. The activity was extracted in high yield from nucleoli with 0.01 M Bis/Tris (pH 7.0). Low ionic strength was also required for activity: the activity was only 50% of maximum in 0.075 M NaCl. Activity was affected differently by various divalent cations: MgCl2 had little effect: CaCl2, MnCl2 and CoCl2 above 4 mM inhibited the activity 30--60%; ZnCl2 above 2 mM completely destroyed the activity. EDTA had no effect, indicating that divalent cations are probably not required. The enzyme activity was enhanced 20% by 5--8 mM dithiothreitol and was inhibited 60% by 7--10 mM N-ethylmaleimide indicating a requirement for free sulfhydryl groups. The Km of the extracted enzyme for 32P-labeled nucleolar protein was 0.6 mg/ml. The phosphatase was capable of dephosporylating the major phosphorylated nucleolar proteins C23-24 and B23-24 and also histone H1. The enzyme was purified more than 200-fold on hydroxyapatite followed by DEAE-Sephadex, which resolved the activity into three major components. The activity of enzyme extracted from Novikoff hepatoma nucleoli was approximately 2.5 times greater than from normal liver nucleoli.
Biochim Biophys Acta 1978 Sep 11
PMID:Nucleolar phosphoprotein phosphatase from Novikoff hepatoma and rat liver: characterization and partial purification. 21 Aug 25

Gentle homogenization followed by differential and density gradient centrifugation was used to purify line 10 and line 1 guinea pig hepatoma plasma membranes in the form of ghosts. Yields of 15--25% allowed enough membranes to be obtained from a single ascites tumor-bearing animal for immunologic and biochemical studies. Although the plasma membrane marker enzyme (Na+ + k+)atpase was present in normal concentrations in both line 10 and line 1 hepatomas, 5'-nucleotidase was reduced over 100-fold in both tumors and phosphodiesterase I was increased 210-fold in the line 10 hepatomas.
J Natl Cancer Inst 1978 Sep
PMID:Preparation of plasma membranes from line 10 and line 1 guinea pig hepatomas. 21 Dec 44

1. Naturally-occurring and synthetic analogues of phenylalanine, tyrosine, histidine, arginine, proline, tryptophan and the sulphur amino acids have beeen tested in rat reticulocytes and in the Reuber H35 hepatoma for effects on protein synthesis and protein degradation and on the heat lability of phosphoenolpyruvate carboxykinase (EC 4.1.1.32) in the hepatoma cells. The experiments were designed to test whether the analogues could be incorporated into mammalian proteins and whether the resultant proteins would be degraded at an accelerated rate. 2. Several analogues, including thiazolylanine, triazolalanine and selenocystine both stimulated protein synthesis and produced labile protein in reticulocytes. Other analogues, such as dihydroxyphenylalanine, thioproline and pipecolic acid accelerated protein breakdown but probably indirectly via an inhibition of protein synthesis. Azetidine-2-carboxylic acid had the largest effect on protein breakdown in reticulocytes. 3. Labile protein was produced in hepatoma cells incubated in the presence of azetidine-2-carboxylic acid, canavanine, indospicine, triazolalanine, 2-, 3- and 4-fluorophenylalanine. These same analogues, together with 3,4-dehydroproline, beta-2-thienylalanine, dihydroxyphenylalanine, histidinol, 5- and 6-fluorotryptophan, selenocystine and selenomethionine produced heat-labile phosphoenolpyruvate carboxykinase. Enzyme induced in the presence of selenomethionine or indospicine showed the largest increases in heat lability, and for these analogues equimolar concentrations of methionine and arginine respectively were needed to nullify the enzyme abnormality. 4. The toxicity of the same naturally-occurring analogues has been discussed in terms of their ability to be incorporated into cell proteins.
Br J Nutr 1978 Sep
PMID:Effects of amino acid analogues on protein synthesis and degradation in isolated cells. 21 95


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