In vitro characteristics of human glioblastomas maintained in organ culture systems. Light microscopy observations.

Light microscopy observations are described on five human glioblastomas grown in organ culture systems, using either a three-dimensional sponge foam matrix technic or a Millipore filter platform technic. Many cultures were successfully maintained for more than 2 months; one was maintained for 137 days. Invasion of the sponge foam matrix by glioma cells was invariably demonstrated. Mitotic figures were seen up to 122 days after explantation. All tumors showed the development of well-differentiated astrocytes; they often showed increased glial fibrillogenesis in the later stages of culture. Oligodendroglia were also demonstrated in one case. The in vivo features of pseudopalisading and endothelial proliferation were not seen. On the contrary, the vascular stroma of several explants showed a marked tendency to undergo sclerosis, with thickening, hyalinization and gradual obliteration of the vascular lumens. The cultural behavior of the explants with this technic was compared with that of sister cultures grown on collagen-coated coverslips. The organ culture technics revealed some important differences in growth characteristics. In contrast to what was seen in collagen-coated coverslip cultures, fibroblastic proliferation was inhibited, and the marked anaplastic cellular features that were sometimes manifest after 4 to 6 weeks on coated coverslips were not seen in the organ cultures.

Plaquing of Toxoplasma gondii in secondary cultures of chick embryo fibroblasts.

A tissue culture system that employed chick embryo fibroblasts was described for plaquing of the obligate intracellular parasite Toxoplasma gondii. High plaquing efficiency and reproducibility were accomplished by the use of secondary rather than primary cultures and the use of toxoplasma obtained from disrupted peritoneal cells of mice infected 48 hr earlier. The monolayers were cultured in a special medium which maintained the fibroblasts until the maximal number of plaques was produced. Optimal plaque formation was obtained in 5 days, and the plaques were easily counted macroscopically.