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

Medroxyprogesterone, dexamethasone, or cortisone, locally applied in sustained release polymer to rabbit V2 carcinoma implanted in the rabbit cornea, blocked neovascularization and three-dimensional growth of the tumor. These hormones similarly prevented the vascular proliferative response to implants in the rabbit cornea of mouse B-16 melanoma and also the response to implants of polymer containing tumor extract with angiogenesis activity. The inhibitory responses were accompanied by considerable reduction in collagenolytic activity released into culture medium by explants of the two tumors and of the corneal region containing angiogenic hepatoma extract. Morphologic studies revealed extensive three-dimensional disruption of the compact laminated collagenous structure of the cornea by untreated V2 carcinoma. In the presence of hormone the tumor grew slowly as a noninvasive two-dimensional plaque limited to the narrow region of the insertion pocket in the cornea, with no obvious disturbance of structure elsewhere. Cortisone was much les effective than medroxyprogesterone or dexamethasone. Testosterone and estradiol had no effect on the three measured properties. The data suggest that local hormonal interference with neovascularization, collagenase production, and tumor growth can prevent neoplastic invasion and destruction of a dense collagenous connective tissue.
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PMID:Inhibition of tumor growth, vascularization, and collagenolysis in the rabbit cornea by medroxyprogesterone. 626 56

After 30 min of intraperitoneal injection of dexamethasone to adrenectomized rats about 15% of the label are incorporated into liver homogenate and only 1% of the cytosol-bound hormone is detected in the cell nuclei. The binding of the "in vitro" injected hormone by the nuclei does not obey the second-order reactions (the Scatchard plots). This is probably due to the existence of various ancillary mechanisms, which control the translocation of the hormone complex into cell nuclei at the level of cytoplasm and nuclear membranes. DNAase I, micrococcal nuclease and endogenous nucleolysis markedly increase the part of the nuclear hormone complex resistant to 0.4 M NaCl. In hepatocyte nuclei obtained by the collagenase method, the content of the 0.4 M NaCl-resistant receptor complex is also increased. The resistance of 0.4 M NaCl was also found in 80% of the glucocorticoid-insensitive nuclear complex from Zajdela ascite hepatoma cells. The changes in interaction of the hormone-receptor complex with nuclear acceptor sites eventually resulting in impaired sensitivity of host tissues to hormonal control can be due to the damage of chromatin structure induced by different influences and tumour growth.
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PMID:[Sensitivity of intranuclear glucocorticoid complex from normal rat liver and Zajdela ascites hepatoma to ionic strength and nuclease treatment]. 626 70

Bovine capillary endothelial (BCE) cells produce increased amounts of the proteases plasminogen activator (PA) and latent collagenase when cultured in the presence of the following preparations which are known to contain angiogenic activities: bovine retinal extract, mouse adipocyte conditioned medium, and human hepatoma cell lysate. These preparations stimulated both BCE cell PA and collagenase activities in a dose-dependent manner. Both activities were increased to about the same level by these preparations as by the tumor promoter 12-O-tetradecanoylphorbol 13-acetate. Mitogens that are not angiogenic, such as insulin, epidermal and fibroblast growth factors, and endothelial cell growth supplement, had no effect on BCE cell PA and collagenase activities. Two of the angiogenic preparations (retinal extract and mouse adipocyte-conditioned medium) had no effect on PA activity in endothelial cells derived from bovine aortae (BAE cells). The angiogenic preparations had little (human hepatoma cell lysate, mouse adipocyte-conditioned medium) or no (bovine retinal extract) effect on BAE cell collagenase activities. In the bovine system, the induction of high levels of both PA and collagenase activities by angiogenic preparations is limited to capillary endothelial cells.
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PMID:Increased capillary endothelial cell protease activity in response to angiogenic stimuli in vitro. 630 97

Several angiogenic preparations that have been shown to stimulate plasminogen activator (PA) and collagenase production by cultured bovine capillary endothelial (BCE) cells were tested for their ability to stimulate BCE cell motility in the phagokinetic track assay. Bovine retinal extract, medium conditioned by 3T3-F442A differentiated mouse adipocytes, SK HEP-1 human hepatoma cell lysate, mouse sarcoma 180 cell lysate, and medium conditioned by mouse sarcoma 180 cells stimulated motility 68.7%, 48.5%, 140.9%, 56.5%, and 102.1%, respectively, relative to untreated cells. The motility-stimulating activity of these preparations was dose dependent and linear over the 16-h assay period. Several hormones and growth factors were tested for BCE cell motility-stimulating activity, including insulin, vasopressin, fibroblast growth factor, and a partially purified preparation of sarcoma growth factor, and were found to be ineffective. 12-0-tetradecanoyl-phorbol-acetate (TPA), a potent stimulator of both PA and collagenase activities in BCE cells, also did not stimulate motility, indicating that protease production is not sufficient to stimulate BCE cell motility in this assay. Neither SK HEP-1 hepatoma cell lysate nor TPA was effective in stimulating motility in bovine aortic endothelial (BAE) cells. The inability of SK HEP-1 hepatoma cell lysate to stimulate movement in BAE cells is consistent with the observation that angiogenesis occurs by sprouting of capillaries, not large vessels.
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PMID:Stimulation of motility in cultured bovine capillary endothelial cells by angiogenic preparations. 632 76

To improve the in vitro growth of Plasmodium falciparum we attempted to cultivate its erythrocytic stages on monolayers of functionally active hepatocytes. Hepatocytes from Swiss Albino mice were isolated by perfusing the liver with a collagenase solution and were co-cultured with a liver epithelial cell type in RPMI 1640 medium supplemented with 10% human umbilical cord serum. The results show that the presence of hepatocytes improves both the multiplication rates of three strains of P. falciparum already in cultivation and the proliferation of freshly isolated strains. Of nine primary isolates tested, only three could be adapted in the standard conditions, whereas all grew readily in the presence of hepatocytes. After two to three weeks of culture with feeder cells, all the strains could be maintained continuously in standard conditions. Similar results were obtained using hepatocytes from another rodent species. Growth was also improved using the supernatant from hepatocyte cultures. No improvement resulted from the use of two human hepatoma cell lines, one rat hepatoma, human embryonic lung fibroblasts, human liver fibroblasts and rat liver epithelial cells as feeder layers. From these results it appears that better culture media can be designed and that the effect of hepatocytes is probably related to the specific functions exhibited by these cells. Hepatocytes may act either by removing toxic substances, particularly lactic acid in the Krebs and Cori cycles, and/or supplying nutrients essential to the parasite.
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PMID:Hepatocytes as feeder-layers for in vitro cultivation of Plasmodium falciparum blood-stages. 638 21

Improvements in the collagenase perfusion techniques have made isolated rat hepatocytes a popular model in which to study hepatic function. Our knowledge of hepatic amino acid transport has been advanced as a result of this methodology. Translocation across the hepatocyte plasma membrane can, in some instances, represent the rate-limiting step in the overall metabolism of certain amino acids. Furthermore, regulation of amino acid uptake by hepatocytes appears to play a role in diabetes, and perhaps in malignant transformation. Comparisons between normal adult hepatocytes and several hepatoma cell lines show basic differences in amino acid transport. There are at least eight distinct systems in normal hepatocytes for transport of the hormones. Systems A and N exhibit enhanced uptake rates after the cells have been maintained in the absence of extracellular amino acids, a phenomenon termed adaptive control. Further studies using isolated hepatocytes will increase our basic understanding of membrane transport processes and their regulation.
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PMID:Amino acid transport in isolated rat hepatocytes. 681 49

In this paper the recognition of various rat tumor cells by rat liver cells is demonstrated in vitro. A liver cell receptor involved in the binding process has been identified. The ultrastructure of the cell contacts was examined by transmission electron microscopy. Hepatocytes and Kupffer cells were isolated from rat liver by collagenase treatment and cell adhesion tests were performed with 4 different tumor cells types. Hepatocytes were found to bind Walker sarcoma cells, lymphoma cells and Yoshida hepatoma cells but not leukemia 5222 cells. Kupffer cells bound all tumor cell types. Normal blood cells were not bound under the same conditions. Recognition of tumor cells by hepatocytes was mediated by a galactose specific lectin on the liver cell surface as shown by hapten inhibition experiments with specific saccharides. Although Kupffer cells express a similar lectin-like receptor adhesion of tumor cells could not or only slightly be inhibited by galactose or related saccharides. It is concluded that the spontaneous adhesion of tumor cells to liver cells in vitro is a specific recognition event which in part is mediated by lectin-carbohydrate interactions.
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PMID:Galactosyl specific receptor on liver cells: binding site for tumor cells. 728 63

Administration of diethylnitrosamine p.o. to female Sprague-Dawley rats induces hepatocellular lesions antecedent to hepatocarcinoma (altered foci and hyperplastic nodules). We have tested hepatocytes from hyperplastic nodules for their invasiveness in vitro, which is a marker for malignancy. The hyperplastic nodule cells are compared with control liver cells and hepatocarcinoma cells. Control liver tissue and the hepatocarcinoma are collected as fragments taken directly from the rat liver. Nodules, on the other hand, isolated by collagenase perfusion of the liver, are collected on a filter. The fragments of normal liver, the nodules, and the hepatocarcinomas were brought in contact with precultured 9-day-old embryonic chick heart fragments for attachment to each other to form confronting cultures. After attachment, the confronting cultures are incubated at 37 degrees on a gyratory shaker for 24 hr to 14 days. Hepatocytes from the nodules show progressive invasion into the precultured heart fragments in the same way as the hepatocarcinoma cells after 3 to 14 days in vitro. The control hepatocytes from the liver fragments showed no invasion. We conclude from these observations that the cells of the nodules must be considered as malignant altered hepatocytes, for they show progressive invasiveness in vitro.
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PMID:Invasiveness of hyperplastic nodule cells from diethylnitrosamine-treated rat liver. 730 12

Recently, we purified rat thrombopoietin (TPO) from plasma of irradiated rats (XRP) by measuring its activity that stimulated the production of megakaryocytes from megakaryocyte progenitor cells (CFU-MK) in vitro. We then cloned the cDNAs for rat and human TPO. In this study, we found the production of TPO by hepatocytes isolated with the collagenase perfusion method from both normal and thrombocytopenic rats, by a two-step fractionation of hepatocyte culture medium (CM). Subsequently, CM of rat hepatoma cell lines was screened for the presence of TPO; three cell lines, H4-II-E, McA-RH8994, and HTC, were found to produce TPO. According to the purification procedure for TPO from XRP, TPO was partially purified from 2 L CM of each of three cell lines with a six-step procedure. In the final reverse-phase column, TPO from each cell line was eluted with the same retention time as that from XRP, and the TPO fraction exhibited megakaryocyte colony-stimulating activity (Meg-CSA). TPO-active fraction eluted from the final reverse-phase column was separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), extracted from the gel, and assayed. TPO activity from each cell line was found in the respective molecular weight region, indicating the heterogeneity of the TPO molecule. Using reverse transcriptase-polymerase chain reaction (RT-PCR), we detected the expression of TPO mRNA in hepatocytes, three hepatoma cell lines, normal rat liver, and X-irradiated rat liver. Northern blot analysis showed that TPO mRNA was expressed mainly in liver among the various organs tested. These data demonstrate that TPO is produced by rat hepatocytes and hepatoma cell lines and suggest that liver may be the primary organ that produces TPO.
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PMID:Production of thrombopoietin (TPO) by rat hepatocytes and hepatoma cell lines. 749 68

The reverse hemolytic plaque assay (RHPA) uses complement-mediated red blood cell lysis to detect peptide secretion by individual cells. Initially, the RHPA was used to study the function of neurons and B lymphocytes. More recently, the RHPA has been adapted to measure hormone release from individual pituitary, parathyroid, luteal, and pancreatic islet cells. We have applied this technique to detect insulin-like growth factor binding protein-1 (IGFBP-1) secretion by a human hepatoma cell line (HepG2). We proposed that the technique of RHPA could be used to study peptide release from single hepatocytes in various defined conditions. Our goal was the study of the kinetics of IGFBP-1 secretion from hepatoma cells and rat hepatocytes and to determine the heterogeneity of the cell population regarding the secretion of IGFBP-1. To evaluate the optimal conditions of IGFBP-1 secretion by hepatoma cells and rat hepatocytes and to evaluate the influence of cell dispersion on hepatocyte's behavior, we evaluated three techniques of cell dispersion: trypsin digestion, collagenase digestion, and mechanical dispersion. We tested cell viability, determined the percentage of secreting cells versus non-secreting cells, and measured mean plaque area which is a function of the amount of IGFBP-1 secreted by an individual cell. We determined the optimal IGFBP-1 antibody dilution for the detection of secreted IGFBP-1 by hepatocytes, evaluated the initiation of IGFBP-1 secretion from cultured cells, and quantified time-dependent IGFBP-1 secretion. In addition to demonstrating the feasibility of measuring IGFBP-1 from a cultured cell line, we measured IGFBP-1 release from freshly dispersed rat hepatocytes.
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PMID:Secretion of insulin-like growth factor binding protein-1 from individual hepatocytes. 753 Jan 14


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