IN VIVO INCORPORATION OF TRITIATED THYMIDINE IN ACUTE LEUKAEMIA CHROMOSOMES
The in vivo incorporation of tritiated thymidine into the chromosomes of a patient with acute leukemia was investigated. Ten mc of tritiated thymidine was injected intravenously. 50.6% of the mitotic figures (out of a total count of 420 mitoses) showed evidence of labeling: owing to the experimental conditions, tagged mitotic figures could only be found in the cells that had incorporated the precursor in the final stages of the synthetic period, whereas the unlabeled figures correspond to cells that were past the S stage at the time of labeling. From the results it was concluded that: duplication of DNA follows not a randdom course but a particular time sequence not only in normal blood cells but also in acute leukemia cells. The time sequence presents the same features in euploid cells as in aneuploid cells. Incorporation of the DNA precursor was also achieved by the extra-chromosomes. The synthetic phase of the Y chromosome in the present case of acute leukemia differed from that of the small acrocentric chromosomes. The ratio of labeled to non-labeled mitotic figures suggested the possibility that the post-synthetic period is shorter in vivo than in vitro. (P.C.H.)
- Research Organization:
- Medical School, Turin
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-18-004987
- OSTI ID:
- 4123824
- Journal Information:
- Nature, Journal Name: Nature Vol. Vol: 200
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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