a quantitative electron microscopic analysis of human preimplantation embryos in conjunction with [ 3h ] uridine labeling and light microscopic autoradiography revealed significant differences in the fractional volume of some cell organelles between the blastomeres of eight-cell embryos with fully activated extranucleolar and nucleolar transcription and those showing low extranucleolar and no nucleolar rna synthesis , a pattern typical of four-cell human embryos .
C1281743
preimplantation embryos
C0005712
blastomeres