methylation level as expressed by the molar ratio of 5-methylcytosine content to the combined content of cytosine and 5-methylcytosine was determined by hplc and uv adsorption of cellular dna extracted from sv40-infected and pretransformed mrc-5 human diploid fibroblasts ( hdfs ) during their limited in vitro life span .
C0007634
cellular
C0016030
fibroblasts