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Biomedical subjects

A BENDICH

Publications and source records attributed to A BENDICH.

At least 19 recordsLinked to original sources

CIRCULATING DNA AS A POSSIBLE FACTOR IN ONCOGENESIS.

Infectious DNA from the tumor-inducing polyoma virus and pneumococcal-transforming DNA can be recovered from the blood of mice in biologically active form after intraperitoneal injection. Polyoma DNA appeared to undergo less inactivation than did transforming DNA. In light of these observations, the metastatic spread of cancer may possibly be favored by circulation of tumorigenic DNA in the blood stream.

Administration, Intravenous↗

STUDIES ON THE ISOLATION OF METAPHASE CHROMOSOMES.

A method for the isolation of metaphase chromosomes from mouse L1210 leukemia cells has been developed. Cells, arrested at metaphase with colchicine, were exposed to hypotonic solution and the pH was then adjusted to 5.6 to stabilize the chromosomes. The metaphase figures were subsequently disrupted and the chromosomes isolated by a series of differential centrifugations in sucrose. The isolated chromosomes were well preserved, as judged by morphological criteria. The effect of various enzymes and chemical agents on the isolated chromosomes was studied. Chymotrypsin, trypsin, and deoxyribonuclease caused a marked disintegration of the chromosomes, whereas treatment with pepsin and ribonuclease induced no significant morphological alterations.

Centrifugation↗

UPTAKE OF MAMMALIAN CHROMOSOMES BY MAMMALIAN CELLS.

Chromosomes isolated from mouse leukemia L1210 cells were taken up by mouse macrophages, HeLa cells, and rat embryo fibroblasts following simple exposure in vitro. The process, which resembles pinocytosis or phagocytosis, was traced by autoradiography of chromosomes prelabeled with thymidine-H(3), and by staining techniques and phase contrast microscopy. During the first six hours, the uptake of chromosomes was restricted to the cytoplasm, but there was some evidence of penetration into the nucleus after 16 and 26 hours of exposure. Treatment of rat fibroblasts with glucose and insulin markedly enhanced the uptake of chromosomes, whereas iodoacetate inhibited their penetration.

Animals↗