Low plasma cell 3(H) thymidine incorporation in monoclonal gammopathy of undetermined significance (MGUS), smouldering myeloma and remission phase myeloma: a reliable indicator of patients not requiring therapy.

The kinetics of bone marrow plasma cells were evaluated by means of in vitro 3(H)thymidine incorporation in 143 patients with monoclonal gammopathies. Fifty-three patients had symptomatic multiple myeloma (MM) at diagnosis, nine were in stable remission, six in unstable remission, and 16 in the relapse phase. Thirty-seven patients were classified has having monoclonal gammopathy of undetermined significance (MGUS) and 22 as smouldering myeloma (SM).

Differences in the in vitro growth pattern of fresh and cryopreserved granulo-monopoietic precursors.

A study of the in vitro growth model of human granulo-monopoietic precursors (CFU-GM) before and after cryopreservation using both leukocyte feeder layers and GCT conditioned medium as the source of colony stimulating activity (CSA) is reported. The number of colonies produced with fresh cells was linearly related to the amount of marrow seeded with both CSA sources, whereas after cryopreservation this was true with feeder layers, and with GCT only at relatively high cell concentrations. This might indicate the production of granulopoietic stimulators on the part of a second population that is at least partly resistant to freezing.

[Current clinical use of radioisotopes in the study of platelet kinetics].

Radioisotopic study of platelet kinetics can provide a preliminary orientation in the diagnosis of thrombocytopenia. A study of the platelet kinetics in thrombocytopenic and normal subjects using the Cr51 isologous platelet labelling technique and subsequent in vivo injection of the labelled platelets was conducted. The results obtained confirm the reliability and usefulness of the technique.