Two human cell lines (GL15 and GL22) derived from glioblastoma multiforme were established and characterized by immunohistochemical and cytogenetic techniques. The expression of glial fibrillary acidic proteins and the karyotype were analyzed at different passages for both cell lines. The course of marker-pattern differed in the two cell lines. The main findings were a cell-density-dependent expression of glial fibrillary acidic protein in the cell line GL15 at all passages and a decreased expression of this protein over time in the cell line GL22. Both cell lines had hyperdiploid karyotypes and exhibited glioma-specific chromosomal abnormalities (gain of chromosome 7 and loss of chromosome 10). In the GL15 cell line no relevant chromosomal changes were produced during culturing, whereas in the GL22 cell line a hypodiploid clone appeared at the 42nd passage. The immunohistochemical and cytogenetic data resulting from this study confirm that the two cell lines established in our laboratory originated from astrocytic tumor cells.

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Cell morphology, protein/DNA ratio, ganglioside analysis, taurine uptake, and the activity of neurone specific enolase showed that neuronal cells mature faster when grown on polyethyleneimine coated plates compared to cells grown on polylysine coated plates. Our results also show higher protein/DNA ratio and total and neuron specific enolase activities in cells grown in serum supplemented medium, when compared to their counterparts grown in synthetic medium. Moreover, our results show that only some specific markers can be used to determine the early and late events of cell maturation, whereas other markers continuously vary with time.

Abstract— Brain phosphoglycerides are known to contain large amounts of polyunsaturated fatty acids (PUFA). However, neuroblastoma cells contain very low amounts of PUFA. Since the serum used for cell culture has been shown to be deficient in PUFA, a supplementation of this serum with various PUFA was undertaken. Linoleic, arachidonic and docosahexaenoic acids were incorporated in cell phosphoglycerides, mainly at the expense of oieic acid, while linolenic acid was only poorly incorporated. Linoleic. linolenic and arachidonic acids were transformed to their elongation and desaturation products; but the last step of transformation, which involves the action of a Δ 4 desaturase, was never observed. The levels of incorporation and transformation of exogenous PUFA could vary strikingly in different lines of neuroblastoma cells. The simultaneous addition of two PUFA (linoleic and linolenic acids) was followed by a reduction in the amount of their respective derivatives in cell phosphoglycerides. compared to that obtained when only one PUFA was given to the cells, suggesting a competitive inhibition of the desaturation of each PUFA. Such alterations in membrane lipids may provide a useful model for the study of membrane structure‐function relationships.