Bleomycin-induced fine structural alterations in cultured mouse fibroblasts and human lymphocytes of neoplastic origin.

human neoplastic disease origin exposed to the new antitumor antibiotic, bleomycin, show a variety of morphological alterations. Bleomycin-treated cells are larger than untreated cells and often contain multiple nuclei. Hypertrophy of cellular organdÃ-es like mitochondria and Golgi vesicles is accompanied by nuclear enlargement. In a majority of the treated cells, nuclei, which appear hyaline in light micrographs, show the total absence of electron-dense chromatin clumps. Extensive infoldings and lobulation of the nuclear surface and initial nucleolar hypertrophy, followed by shrinking and segregation of the nucleolar components, are seen in drugtreated cells.