Cytoplasmic DNA synthesis by cord blood cells of premature and full-term infants

Summary Cord blood cells from 8 full-term and 12 premature infants as well as blood leukocytes from 10 adults were incubated with³H-thymidine and were subsequently exposed to autoradiographic emulsion for prolonged periods of 45 and 90 days. Cytoplasmic label — which we interpreted as evidence of mitochondrial DNA synthesis — was found in 1.7 per cent of lymphoid cells from adult blood, in 2.9 per cent and 4.5 per cent of lymphoid cells from full-term and premature infants, respectively. Statistical analysis of the data shows that the number of labelled cells is significantly larger in the blood of premature infants than in adults (p<0.01).On leave from the Department of Pediatrics, University of Göttingen, West-Germany, under the auspices of the Committee for Scientific Co-operation between German Institutions and the Weizmann Institute