Down's syndrome (DS) is the most common chromosomal abnormality in human. Subjects with DS are known to be peridisposed to develop leukemia. The molecular basis of the association between DS and leukemia is unknown. The unscheduled DNA synthesis (UDS) test measure the ability of DNA-repair in mammalian cells after excision of a stretch of DNA containing the region of damage induced by chemical ...

Chemical or physical modification of DNA may cause an increase in genomic mutations or other genetic alterations, which may ultimately result in the onset of cancer. To avoid these deleterious effects of DNA damage, humans possess DNA repair mechanisms. Decreased DNA repair, induced ex vivo by UV light or ionizing radiation in human peripheral blood lymphocytes (PBLs), has been associated with ...

Cellular DNA can suffer single-stranded chemical damage as a consequence of exposure to highenergy radiation or certain chemicals. Bacteria can repair this damage by excising a segment of the damaged strand and synthesizing a new segment complementary to the undamaged strand (14) . Mammalian cells can also be induced to synthesize small amounts of DNA, when they would not ordinarily be doing so...

Direct measurements of the genetic hazards to man have been determined previously by the appearance of elevated in vivo levels of chromosome aberrations. Here we report that interindividual variations in N-acetoxy-2-acetyl-aminofluorene-induced unscheduled DNA synthesis values parallel the actual in vivo levels of chromosome damage and, therefore, may be a rapid useful supplement in genetic ris...

A technique has been developed for handling human bone marrow cells intended for the examination of DNA repair synthesis. DNA-repair synthesis, induced by melphalan and nitrogen mustard, was measured as the incorporation of 3H-thymidine, registered by autoradiography as unscheduled DNA synthesis (UDS). Comparison of various cell populations disclosed considerable differences in their UDS level,...