The activity of nucleolar organizer regions of human bone marrow cells studied with silver staining. I. Chronic myelocytic leukemia.

The activity of nucleolar organizer regions (NORs) in chromosomes and interphase nuclei of bone marrow (BM) cells from 21 patients with chronic myelocytic leukemia (CML), including seven patients at the time of blastic crisis (BC), has been studied with silver nitrate staining. The average numbers of Ag-NOR per metaphase in PHA-stimulated peripheral blood lymphocytes from patients with CML and normal individuals were 7.1 +/- 0.3 and 7.4 +/- 0.1, respectively, indicating no statistical difference between them. Those in BM cells from patients with CML, as in the normal donors, were more heterogeneous compared to PHA-stimulated lymphocytes, and most of the metaphases (up to 67%) did not contain silver-stained NORs. The average number of Ag-positive NORs in BM mitoses from untreated patients in the chronic phases of CML and from those in the BC were similar (4.9 +/- 0.3 and 4.8 +/- 0.4, respectively). As for NORs of the Ph chromosome, they were Ag-positive in the majority of patients, including 9 of 14 in the chronic phase and 3 of 7 in the BC. This article contains some data in support of the authors' previous assumption regarding the correlation between BM Ag-NOR patterns and the degree of maturity of the cells tested in mitosis.