Karyotyping of bone-marrow cells in hematologic diseases

Cultures of bone-marrow cells incubated for 5 h at 4 degrees had cells in metaphase with elongated chromosomes which were easily Giemsa banded. Colcemid was not necessary for metaphase arrest at this temperature. This technique made possible routine karyotyping of patients with leukemia and other hematological diseases in which the detection of aberrations was otherwise difficult.