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Biomedical subjects

H L Su

Publications and source records attributed to H L Su.

23 records · Page 2Linked to original sources
PubMed1983

Mutagenicity of cyanate, a decomposition product of MNU.

Knox reported that the short-term effects of the carcinogen methylnitrosourea (MNU) were due to the formation of its decomposition product, the cyanate ion. He showed that cell survival and DNA synthesis decreased as the concentration of MNU and the cyanate ion (NCO-) increased in the medium. Further, the product of MNU decomposition comigrated with NCO- when added to his chromatographic test system. However, Knox did not study the mutagenicity of MNU or its breakdown products. We compared the mutagenicity of MNU and potassium cyanate (KNCO) in mammalian cells. Our results demonstrate that, although it is toxic to cells, KNCO does not induce ouabain-resistant mutants in cultured Chinese hamster cells (V79).

Animals↗
PubMedDate not supplied

The mechanisms of the inhibitory effects of liver extract on lymphocyte proliferation. III. The effects of arginase on DNA polymerase activities.

The incorporation of labeled precursors into DNA, RNA and protein in phytohaemagglutinin (PHA)-prestimulated human lymphocytes was maximally inhibited by liver extract (LEx) or arginase at 24 h. The activities of DNA polymerase alpha, beta and gamma were less inhibitable by these agents than was [3H]thymidine incorporation. The inhibition of DNA, RNA and protein syntheses by either LEx or arginase is probably due to arginine depletion by arginase activity, since their syntheses were similarly inhibited when cultured in an arginine-free medium in the absence of arginase. These results indicate that arginase nonspecifically inhibits the activities of DNA polymerase. The inhibition is probably due to arginine depletion.

Animals↗
PubMedDate not supplied

Mesiodens in the primary dentition stage: a radiographic study.

Five hundred and forty-three Chinese patients in the primary dentition stage were evaluated for mesiodens with maxillary, anterior occlusal films. Compared with other studies, a higher prevalence was found, using different age-groups and diagnostic methods. The distributions of mesiodens by sex, location, and direction were also studied. Because mesiodens could interfere with normal development of the occlusion, especially in the early mixed dentition stage, early diagnosis, using appropriate radiographs during the primary dentition stage, could lead to more comprehensive treatment planning.

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