Elsa Anton

Ultrastructural and cytochemical changes in cultured human lung cells

Human diploid cells (WI-38) in culture show marked ultrastructural and cytochemical differences from the various mesenchymal cells present in the fetal lung. The cultured cells show hypertrophic RER cisternae studded with helical polyribosomes. A complex system of microtubules and filaments develops in the cultured cells, which also show an abundance of microvesicles formed at both the cell surface and in the Golgi. The vesicles at the cell surface are actively engaged in pinocytosis of macromolecules in the medium, and those in the Golgi represent primary lysosomes. Microtubules and filaments are very labile structures, and appear to play a role in the maintenance of cell form and in intracytoplasmic flow. Secondary lysosomes, residual bodies, and autophagic vacuoles increased with passage level. It is not clear, however, whether this change is associated with cellular degradative processes or whether it pertains to the aging process in vitro .

Lysosomes in mice mammary tumors treated with cyclophosphamide: Distribution related to course of disease

Transplantable carcinomas of mouse mammary gland were treated with cyclophosphamide at various dose levels ranging from 50 to 300 mg/kg body weight. The degree and the length of the period of tumor growth inhibition increased with the dose. Increased activity of the lysosomal enzyme, acid phosphatase, was observed in the tumor cells of treated mice, especially at the dose levels of cyclophosphamide that inhibited tumor growth (200 to 300 mg/kg). Lysosomal acid phosphatase activity remained present during the entire period of growth inhibition but decreased at the time when tumor growth was resumed and disappeared almost completely when the growth rate approximated that of the untreated controls. Combined treatment with the cytotoxic agent and a lysosomal labilizer, vitamin A, increased both the inhibitory effect of cyclophosphamide and the acid phosphatase activity in the tumor cells. In the electron microscopic preparations, the tumor cells of treated mice showed areas of focal degradation and widespread ultrastructural alterations which frequently were associated with lysosomes.

Studies of L-1210 leukemia: IV. Ultrastructural findings after in vitro treatment with cyclophosphamide and Vitamin A

Abstract The influence of normal liver and Vitamin A on the activity of cyclophosphamide on the L-1210 leukemia was investigated in short-term organ cultures. The experimental data presented here support the hypothesis that some principle in the liver is instrumental in the biologic activation of cyclophosphamide. It is also suggested that Vitamin A may alter the permeability of lipoprotein membranes and favor the release and diffusion of lysosomal or microsomal enzymes, or both, and that such enzymes may play a role in the activation process and in tumor-cell damage. Vitamin A also appeared to induce changes in the leukemic cells, reflected in a pseudoepithelization of the lymphoid elements. Increased phagocytosis of red cells by leukemic cells and macrophages, and characteristic changes in the phagocytized corpuscles is also attributed to the action of Vitamin A.

Role of lysosomes in cellular lytic processes. IV. Ultrastructural and histochemical changes in lymphoid tissue of thymectomized mice with wasting disease.

Lymphoid tissues obtained from mice with wasting disease resulting from neonatal thymectomy were examined by histochemical and electron microscopical techniques. The lymphoid organs showed loss of architecture, depletion of lymphocytes, and marked infiltration of macrophages. Plasma cells, however, were numerous. Macrophages were frequently engaged in the phagocytosis of altered lymphocytes, and their degradation within the phagocytic vacuoles appeared to be due to hydrolytic enzymes derived from macrophage lysosomes. Stages in the maturation of myeloid cells, including the development of lysosomes in the Golgi apparatus, were readily detected in the spleen. Neither bacteria nor viruses were detected in the lymphoid tissues, and a possible role of lymphocytic phagocytosis in the depletion of lymphocytes is suggested.