In vitro culture observations on neurinoma induced experimentally in the rat by ethylnitrosourea

Scanning electron microscopy of in vitro grown cells from experimentally induced neurogenic tumors

Serially transplanted neurogenic tumors of experimental origin were explanted in vitro and analyzed by scanning electron microscopy. In explants of intracerebrally transplanted gliomas, small stellate cells with branching processes were observed; in transplanted tumors of the peripheral nervous system, slender bipolar cells as well as fibroblasts emerged. The stereoscopic features were compared with the picture of conventional light microscopy. The findings are consistent with the assumption of the glial derivation of CNS-tumors induced with neurotropic alkylating carcinogens. The peripheral tumors are composed of Schwann-cell like elements and fibroblasts. The significance of the results for the cytogenetic derivation of brain tumors are discussed.

The nature of macrophages (foam cells) in neurinomas. Tissue culture study

Fourteen cases of neurinomas of variable location are studied by tissue culture technic in an attempt to typify the foam cells as primary or superimposed elements in the tumor population. Our results demonstrate that the "in vitro" behavior of the neurinomas is constant and characteristic and that three cell types are found in them: fusiform, star-shaped cells and macrophages. There appears that the macrophage is an evolutive aspect of the star-shaped cells and probably of the fusiform one. On this basis, macrophage and foam cells of neurinomas must be considered as primary.

Bovine normal peripheral nerve and nerve sheath tumour in explant culture

When bovine normal nerve and nerve sheath tumours were cultured using explant techniques, the same morphological cell types were seen:thin bipolar cells with bulging nuclei;found refractile cells; large quadrangular cells; variable polar, wide-processed cells. However, differences in the pattern of cell growth and the proportions of morphological cell types occurred between normal and tumour nerve. The bovine nerve sheath tumours cultured showed a range of histological areas which did not appear to affect the pattern of cell growth in culture or the cell types present. Antoni type A tissue was prominent in many explant blocks and probably gave rise to most cell growth. On comparison with human schwannomas maintained in explant culture, bovine nerve sheath tumours appeared to have a similar range of morphological cell types. Although suggestions for the origin of human schwannomas have been made on the basis of cell morphology, it was felt that morphology alone did not allow speculation on the origin of cells present in bovine nerve sheath tumour explant cell growth.

Studies on experimental malignant nerve sheath tumors maintained in tissue and organ culture systems. I. Light microscopy observations

Explants from seven nerve sheath tumors (four cranial and three spinal) induced in rats by transplacental ethylnitrosourea were grown on collagen-coated coverslips and in organ culture systems, using sponge foam matrices and Millipore filter platforms. Their sequential morphological features in vitro were compared to those of a human acoustic Schwannoma maintained in similar culture systems. The original experimental tumors were either undifferentiated or poorly malignant Schwannomas. In cultures on collagen-coated coverslips the explants demonstrated cellular features that were considerably more anaplastic than those of the human acoustic Schwannoma. On the other hand, in organ culture systems, in which viable cultures were maintained up to 82 days, many of the experimental tumor explants exhibited progressive differentiaiton, with nuclear palisading, increasing whorl formation and abundant reticulin fibers, and their pattern of histological organization came therefore closely to resemble that of the cultured acoustic Schwannoma. Unlike the latter, however, the cultured experimental tumors infiltrated the sponge foam matrices, a feature that mimicked the invasive character of the original tumors in vivo. Included normal ganglion cells remained demonstrable in the cultures up to 69 in vitro.