title: Nuclear DNA-polymerase estimation in human leukaemic myeloblasts.
abstract: A technique which detects the presence of DNA-polymerase in cell nuclei by measuring the incorporation of 3H-thymidine-5-triphosphate (3H-TTP) has been used to estimate the proportion of leukaemic myeloblasts which contains DNA-polymerase and DNA capable of acting as primer-template. In six cases of previously untreated acute myeloid leukaemia the 3H-TTP labelling index (3H-TTP LI) was much larger than the fraction in DNA synthesis. After a single 'flash' injection of cytosine arabinoside a pronounced decline was observed in the 3H-TTP LI, which can be explained by a direct inhibition of NDA-polymerase. No change was observed in the fraction of cells labelled with 3H-thymidine. A decrease in 3H-TTP LI was also observed after a single i.v. dose of methotrexate.
mesh_terms: D001853:Bone Marrow / Q000201:enzymology* / Q000378:metabolism; D001854:Bone Marrow Cells; D002467:Cell Nucleus / Q000201:enzymology; D002471:Cell Transformation, Neoplastic; D003561:Cytarabine / Q000494:pharmacology; D004254:DNA Nucleotidyltransferases / Q000032:analysis*; D006801:Humans; D066298:In Vitro Techniques; D015470:Leukemia, Myeloid, Acute / Q000032:analysis / Q000201:enzymology*; D008727:Methotrexate / Q000494:pharmacology; D009363:Neoplasm Proteins / Q000032:analysis*; D013936:Thymidine / Q000378:metabolism; D013942:Thymine Nucleotides / Q000378:metabolism; D014316:Tritium
chemical_list: D009363:Neoplasm Proteins; D013942:Thymine Nucleotides; D003561:Cytarabine; D014316:Tritium; D004254:DNA Nucleotidyltransferases; D013936:Thymidine; D008727:Methotrexate