BrdU/Thymidine

IF STEM CELLS are to be introduced into a tissue as a therapeutic mechanism to stimulate the repair of damaged tissue, or in a preliminary study to see merely where they go, scientists must have a way of monitoring what becomes of the stem cells postinjection. One way is to mark the DNA with a chemical that would remain in the DNA for generations of cell divisions. A marker of choice—until recent warnings—has been BrdU, a thymidine analog.

Deoxyribonucleic acid, or DNA, carries the genetic information of an organism, in most every cell (red blood cells do not contain nuclei and therefore do not carry DNA). DNA is made up of four nucleotide bases that contain nitrogenous rings: deoxyadenosine, deoxycytidine, deoxy—guanosine, and thymidine. Deoxy does not ...