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Query: UMLS:C0027819 (neuroblastoma)
 27,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several authors have observed that the plasma levels of carcinoembryonic antigen (CEA) in patients with neuroblastoma were significantly elevated. The present study was undertaken to investigate the nature of CEA activity in neuroblastoma tissue. This tumor tissue contains a small amount of CEA-like substance reacting with anti-CEA serum which is characterized by gamma-globulin electrophoretic mobility, a molecular weight that is approximately equal to that of albumin (4.6S) by gel filtration, and a glycoprotein staining with periodic acid-Schiff (PAS). According to the double immunodiffusion method, this antigen is partially identical to purified CEA of colon carcinoma, and is completely identical to nonspecific crossreacting antigen (NCA). This antigen is, therefore, referred to not as the CEA as described by Gold, but as NCA in neuroblastoma tissue. The elevation of plasma CEA activity in patients with neuroblastoma may be due to the release of NCA from tumor cells, or to the destruction tissues by metastasis, of normal which are rich in NCA, or to a combination of both.
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PMID:Immunologic and biochemical studies on the carcinoembryonic antigen-like substance in human neuroblastoma. 8 82

Binding of thrombin to monolayer cultures of human umbilical vein endothelium is studied. Binding is measured as inhibition by unlabeled ligand of the binding of 125I-thrombin to the cells. Radioactivity bound to cultures at equilibrium is measured after draining but not washing the cells. To correct for unremoved supernatant, 131I-albumin is included as a second label in the medium. Equilibrium between bound and free thrombin is attained within 1 min, and Scatchard analysis indicates a population of approximately 3 x 10(3) sites/cell with a dissociation constant of 10(-10) M, and a larger population with a dissociation constant greater than 10(-8) M. The two populations of sites are also indicated by a biphasic dissociation of bound label. Thrombin inactivated with diisopropyl fluorophosphate binds to the same receptor, with an affinity similar to that of active thrombin. Binding is unaffected by albumin (an acidic protein) and cytochrome c (a basic protein). Cultures of umbilical cord smooth muscle and fibroblasts bind thrombin at least 100 times more weakly than endothelium, and no binding to erythrocytes or a monolayer culture of mouse neuroblastoma is detected.
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PMID:Binding of human thrombin to cultured human endothelial cells. 43 77

Plasma fibronectin (pFN) adhesion mechanisms on inert substrata were evaluated for murine fibroblasts (3T3) and human neuroblastoma (Platt) cells using glass coverslips chemically derivatized with a self-assembled monolayer of aliphatic chains terminated with a specific endgroup to interact with adsorbed pFN: [CH3], [SH], [SCOCH3], [NH2], [SO3H], or underivatized glass [SiOH]. All surfaces bound similar amounts of pFN and facilitated attachment of both cell types within narrow ranges. However, spreading/differentiation responses of cells differed considerably among the surfaces. While 3T3 cells spread and developed microfilament stress fibers comparably on all surfaces, inclusion of an RGDS-containing synthetic peptide in the medium revealed variation in resistance to stress fiber formation mediated by an RGDS-recognizing integrin: [NH2] greater than [CH3] much greater than [SiOH],[SH],[SCOCH3]. Different patterns of neurite formation were observed for neuroblastoma cells: [SiOH], [SO3H] greater than [SCOCH3],[SH] much greater than [CH3] greater than [NH2]. Similarity in cell responses to both [CH3] and [NH2] surfaces argues against a pattern dependent upon the hydrophobicity of substrata. When pFN was diluted to a subsaturable concentration with albumin for adsorption, neuroblastoma responses changed significantly from those observed on pFN-saturated surfaces, for both spreading and neurite generation: [NH2],[SO3H] much greater than [SH], [SCOCH3] greater than [SiOH],[CH3]. Responses to the pFN: albumin mixture were markedly improved from responses after sequential adsorptions, demonstrating "optimization" of pFN conformation (not merely binding) by coadsorption of albumin molecules. In most cases, the [NH2] surface yielded responses distinctively different from the other surfaces. Overall, these data suggest many variations in the conformation of pFN molecules adsorbed to specific inert surfaces, as well as variations in the responses of cell surface receptors to conformationally specific pFNs. They also reveal cell-type-specific changes in differentiated cell responses on derivatized substrata, mediated by different classes of cell surface receptors for the two cell types, and provide optimism for regulating FN-dependent adhesion mechanisms in either positive or negative contexts on biomaterial surfaces derivatized with one or more of these chemical end-groups.
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PMID:Cell-type-specific adhesion mechanisms mediated by fibronectin adsorbed to chemically derivatized substrata. 142 51

The evidence that apolipoproteins are found in the cerebrospinal fluid and low-density lipoprotein receptor is found in the brain suggests that the brain may have an active lipid transport system. In plasma, cholesteryl ester transfer protein mediates the exchange and net transfer of cholesteryl ester and triglycerides among lipoproteins. Cholesteryl ester transfer activity was measured in the cerebrospinal fluid and plasma of ten neurologically normal subjects. Cholesteryl ester transfer activity was readily detectable in cerebrospinal fluid (7.4 +/- 13% cholesteryl ester was transferred per 20 microliters), and this activity was completely abolished with specific antibody against the plasma cholesteryl ester transfer protein. The concentration of cholesteryl ester transfer activity in the cerebrospinal fluid was about 12% of that found in plasma, whereas the concentration of albumin in cerebrospinal fluid was only about 0.6% of that in plasma, suggesting direct synthesis of cholesteryl ester transfer protein within the brain. Cholesteryl ester transfer activity was found in conditioned medium from human neuroblastoma and neuroglioma cells and sheep choroid plexus. The data suggest that cholesteryl ester transfer protein is synthesized and secreted in the brain. This protein could play an important role in the transport and redistribution of lipids within the central nervous system.
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PMID:Cholesteryl ester transfer protein in human brain. 159 77

Blood plasma, serum and its fractions containing components of different molecular weights as well as some identified serum constituents were tested for their action on sodium currents of voltage-clamped, internally dialyzed neuroblastoma cells. Only components with a molecular weight over 50 kDa produced a persistent increase in sodium channel currents (stimulatory effect) and shifts in activation and inactivation curves along the voltage axis towards more negative or positive potentials, respectively (modifying effect). Both modulations taken together provide a somewhat higher level of sodium electro-excitable system activity. Among the identified serum components tested, including those possessing high physiological activity, albumin was the only one which reproduced the effects of whole blood serum both qualitatively and quantitatively. The data obtained allow to assume albumin to play a role of an active substance responsible for the blood plasma or serum effects on the potential-dependent transporting system in the neuroblastoma cell membrane. Albumin seems to be involved in holding the functional activity of sodium channels on a suitable level rather than being involved in any regulatory processes.
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PMID:The action of blood serum and its components on potential-dependent sodium channels in neuroblastoma cells. 166 55

Collections of peripheral blood stem cells (PBSC) from children weighing less than 25 kg have been limited by concern about citrate toxicity. We developed a modified collection technique on the Fenwal CS3000 blood cell separator and used it in three children weighing 8.3, 20 and 24 kg with neuroblastoma involving the marrow. The saline prime was discarded as a mixture of 250 ml red cells, 100 ml fresh frozen plasma, and 100 ml 5% albumin was run into the separator. Heparin (1500 units/h) was used to supplement ACD, which was infused at a low rate (1:25-1:32 vs blood, vs the usual 1:13). No serious difficulties were encountered during or after the collections. A total of 5.7, 4.8 and 6.4 x 10(8) mononuclear cells/kg were collected in six procedures per patient. After cell cryopreservation and patient preparation using high-dose chemotherapy, the cells were thawed in 37 degrees C saline and infused without incident. Hematopoietic recovery was observed, and one of the patients remains in clinical remission after 11 months of follow-up. The addition to previously developed procedures of the use of partial albumin prime, low citrate anticoagulation, and heparin allows convenient and safe collection of PBSC in extremely small children, and these PBSC are effective.
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PMID:Collection and use of peripheral blood stem cells in very small children. 167 23

Blood serum gamma-globulin and albumin were tested for their effect on the sodium currents of voltage clamped internally perfused serum deprived neuroblastoma cells. Albumin in the concentration corresponding to its content in 5% blood serum (22 microM) produced an increase in sodium channel currents and shifts in activation and inactivation curves along the voltage axis towards more negative or positive potentials, respectively. These results both qualitatively and quantitatively reproduce the effects of 5% blood serum observed previously (Zubov, Sal'nikov, 1984, 1986). The addition of gamma-globulin failed to change the parameters registered. The data obtained led us to an assumption of the role of albumin as an active substance responsible for the effect of blood serum on the potential-dependent sodium-transporting system of neuroblastoma cell membrane.
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PMID:[The effect of the high-molecular components of the blood serum--gamma-globulin and albumin--on the sodium channel activity of neuroblastoma cells]. 170 91

Tumor gangliosides are biologically active (immunosuppressive and tumor-enhancing) cell surface molecules which are shed into the circulation in vivo. However, the mechanism of transport of these molecules (i.e., in solution or bound to proteins or other lipids) is not known. To resolve this question we traced, by direct chemical detection, the serum localization of a specific human tumor ganglioside, GD2, shed by neuroblastoma cells. Sera from patients with tumors were separated into the lipoprotein fractions [very low-density lipoprotein, low-density lipoprotein (LDL), and high-density lipoprotein] and lipoprotein-depleted serum. All three lipoprotein fractions contained GD2. 73% of the total GD2 was present in the LDL fraction, while very low-density lipoprotein and high-density lipoprotein contained 21 and 6%, respectively. Significantly, lipoprotein-depleted serum, which would contain both albumin-bound and free ganglioside, was devoid of GD2. Thus, shed neuroblastoma tumor gangliosides are exclusively associated with the serum lipoprotein (and predominantly LDL) fractions in vivo. These findings have implications for the immunological detection of these molecules and the development of approaches to their removal.
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PMID:Localization of shed human tumor gangliosides: association with serum lipoproteins. 173 41

The effects of fatty acids on voltage-dependent potassium (K+) channels in neuroblastoma cells were studied using the whole-cell current recording technique. At a concentration of 5 microM, unsaturated and medium chain length (C10-C14) saturated fatty acids accelerated the apparent inactivation of the K+ current. This effect was reversed by albumin. In the absence of exogenous fatty acids, albumin slowed the inactivation of the K+ current. The acceleration of the K+ current inactivation induced by unsaturated fatty acids was associated with an increase in the sensitivity of K+ channels to 4-amino-pyridine. It is concluded that kinetic and pharmacological properties of K+ channels are, in part, controlled by membrane fatty acids which, in this way, should contribute to an apparent diversity of K+ channels and the modulation of cell excitability.
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PMID:Modification of K+ channel properties induced by fatty acids in neuroblastoma cells. 177 67

The toxicity of bilirubin to the nervous system might be due to its effect on several key enzyme reactions occurring in the intracellular compartment as suggested by in vitro studies. The question of how bilirubin, a molecule with poor solubility in water and organic solvents, interacts with the plasma membrane and reaches intracellular targets is unclear. In an attempt to get some insight into this problem, we have measured the uptake of bilirubin from bilirubin-albumin solutions by the murine neuroblastoma cell line N-115. At a constant total concentration of bilirubin, the initial rate, as well as the extent of uptake, increases with increasing bilirubin to albumin molar ratio (B/A). The binding is reversible, at least partially, as indicated by the ability of albumin to extract cell-bound bilirubin. The cellular uptake of bilirubin was found to depend also on the concentration of bilirubin, on temperature and on pH. The results are not consistent with either a carrier-mediated transport or passive diffusion across the plasma membrane. The data, however, seem to fit a multistep binding of bilirubin to the plasma membrane proposed for the interaction of bilirubin with synaptosomal plasma membrane vesicles, erythrocyte ghosts and lipid vesicles. These studies, thus, reveal the complexity of the binding interaction at the level of the plasma membrane and leave open the question of transport across the membrane.
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PMID:Bilirubin-neural cell interaction: characterization of initial cell surface binding leading to toxicity in the neuroblastoma cell line N-115. 222 72


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