CYTOGENETIC AND SUBMOLECULAR BIOLOGICAL STUDIES ON THE EFFECT OF X RAYS ON METABOLISM OF DEOXYRIBONUCLEIC ACID (DNA) OF EHRLICH'S ASCITES CARCINOMA CELL NUCLEI
Effects of x rays on incorporation of P/sup 32/ into DNA of the tumor cells were studied. The carcinoma was implanted in the abdominal cavity of mice, and on the 7th day after implantation, single whole-body 200- or 500-r doses of irradiation were given. Immediately after irradiation, 1 mu C p/sup 32/g body weight was injected into the abdominal cavity. Mice were then killed at hourly intervals to collect ascitic fluid. Protein was removed to obtain DNA from tumor cell nuclei. In the unirradiated controls, P/sup 32/ uptake in DNA took place relatively rapidly until 12 hours after P/sup 32/ injection but thereafter the rate showed an almost constant value. X irradiation was inhibited division of tumor cells and destroyed many cells. During this period, DNA as a thread-like sediment in ascitic fluid could not be obtained. However, after 9 hours when the effect of x irradiation on tumor celis decreased, the frequency of appearance of abnormal cells decreased and the frequency of mitosis of tumor cells increased, the threadlike DNA sediment could be obtained. Moreover, P/sup 32/ uptake in DNA showed a parallel relation to the frequency of mitosis. It is shown that DNA synthesis in Ehrlich's ascites carcinoma cell nuclei is performed prior to mitosis, and that irradiation inhibits this DNA synthesis and causes degeneration of DNA molecules. No conclusive results were achieved in the nucleotide chromatography experiments. (BBB)
- Research Organization:
- Hiroshima Univ.
- NSA Number:
- NSA-18-005049
- OSTI ID:
- 4162317
- Journal Information:
- Hiroshima Journal of Medical Sciences (Japan), Journal Name: Hiroshima Journal of Medical Sciences (Japan) Vol. Vol: 4; ISSN HIJMA
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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