Density-dependent changes in ganglioside composition, Vibrio cholerae neuraminidase (VCN)-susceptible sialyl residues, and membrane-associated sialidase activity were determined for the cholinergic murine neuroblastoma cell line S20Y. A decrease in total ganglioside sialic acid and VCN-releasable sialic acid was observed with increasing cell density. GM3 was the major ganglioside component of preconfluent S20Y cells, whereas GD1a was predominant in postconfluent cells. Sialidase activity increased in confluent and postconfluent cells and may account for the reduction in total ganglioside sialic acid observed with increasing cell density. In contrast, while adrenergic N115 cells showed a decrease in VCN-susceptible sialic acid residues with increasing cell density, there was no significant change in ganglioside composition or ganglioside sialic acid levels.
is indicative of a poor prognosis.EUROBLASTOMA is one of the most common solid N malignancies of children. The age at which children present with the clinical symptoms associated with neuroblastomas correlates well with the probability of recovery: children less than a year old at the time of diagnosis have a much better prognosis than those over 2 years of age.' Despite improved chemotherapeutic regimens, children over 2 years of age with disseminated disease have proven refractory to combined modality therapy.2 Therefore, investigators have looked for markers that might indicate which tumors will undergo spontaneous regression or be amenable to therapy and which will need improved and possibly innovative aggressive therapy. One class of molecules that has been studied in order to determine whether its composition might have prognostic and/or
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