[Immunization and convulsive disorders in children].
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Biomedical subjects
Publications and source records attributed to S Otawara.
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Cytotoxicity and cytomorphological changes induced in cultured mammalian cells by the application of benzaldehyde, pyrocatechol and their derivatives were examined. Among the compounds tested, 3,4-dihydroxybenzaldehyde (protocatechualdehyde) and 1,2-dihydroxybenzene (pyrocatechol) produced cytomorphological changes characteristic of specific inhibitors of DNA synthesis in V79 cells and EJ-1 cells. However, they did not induce such changes in HeLa cells. 2,3-Dihydroxybenzaldehyde and catecholamines did not produce such characteristic changes in V79 cells. The cytological effects of protocatechualdehyde and pyrocatechol were confirmed by a study on the incorporation of 3H-precursors of DNA, RNA and protein into 3 cell lines.
The mode of cytotoxic action of protocatechualdehyde on V79 cells was examined. The cytotoxicity of protocatechualdehyde on V79 cells was time- and cell cycle-dependent. The lethal action is selective for the cells at S phase only. The cells lethally damaged at S phase seemed to complete their DNA synthesis, although the rate of DNA synthesis became lower and the duration of S phase was prolonged. Some cells arriving at G2 phase directly entered the next S phase without cell division and died of karyorrhexis or karyolysis. Cells treated at stages of the cell cycle other than S showed normal progression of their cell cycle to the G1/S boundary. The block point of the cell cycle seemed to lie a little behind that with hydroxyurea. When the cells at phases other than S were blocked with protocatechualdehyde for 14 hr, elongation of the next S phase occurred after removal of protocatechualdehyde. On alkaline sucrose gradient analysis, little scission of parental DNA was observed in the cells treated with protocatechualdehyde.
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