Objective: This study was to investigate the variables in bone marrow harvesting procedure and individual donor factors which can potentially affect the yield of mesenchymal stromal cells (MSC).Methods: We determined the yield of MSC from bone marrow under different clinical conditions by comparing the MSC colony numbers from: (1) donors of different ages; (2) healthy donors and patients with leukemia; (3) bone marrow aspirated at different time points during marrow harvesting; (4) bone marrow harvested by different needles.Results: During the process of harvesting, the number of MSC significantly decreased with increase number of aspiration, from 675/ml at the initial decreased to 60/ml after 100 ml bone marrow aspirated, and 50/ml after 200 ml bone marrow aspirated. The number of MSC retrieved from leukemia patients (99/ml bone marrow) was significantly lower than that of healthy donors (708/ml bone marrow). However, there was no significant difference in growth rate. There was no significant age-related difference of MSC yielded from donors <55 years. And there was no significant difference in MSC number between the samples from single end-holed needle and those from multiple-side-hole needle.Conclusion: The optimal bone marrow samples for MSC collection should be obtained earlier in the process of harvesting procedure. Bone marrow from donors <55 years was equally good as MSC sources. The autologous MSC from leukemia patients can be utilized for in-vitro MSC expansion.

Essential thrombocythemia is a benign disease of older persons. Chinese patients have a low risk of bleeding, and prior myelofibrosis is a major risk factor for evolution to acute myeloid leukemia. Leukemic transformation with hydroxyurea therapy alone is rare and warrants further prospective studies.

Thirty-nine Chinese patients presenting as essential thrombocythemia (ET) were analyzed retrospectively. The median age at presentation was 69 years and the M:F ratio was 1.35:1. At diagnosis, 33 cases (84%) were asymptomatic and the diagnosis was made incidentally, while 3 cases (8%) presented with small vessel, and 2 cases (5%) with large vessel, thrombosis. One patient (3%) presented with minor bleeding. The platelet count ranged from 0.9-34 x 10(12)/l. Of 12 karyotypes done, 2 cases were abnormal, both showing the Philadelphia (Ph) chromosome. First-line therapy was radiophosphorus (32P) in 3 cases, melphalan in 20 cases, and hydroxyurea in 12 cases; 4 cases did not receive specific therapy. During the follow-up (mean = 4 years), no thrombotic or bleeding episodes were observed. One patient with the Ph chromosome underwent blastic transformation. These results indicate that bleeding and thrombosis occur significantly less in Chinese patients than in Western patients. The Ph chromosome appears to be a bad prognostic indicator. Because of the very low incidence of complications and good prognosis, the authors believe that cytoreductive therapy is best achieved by the use of hydroxyurea instead of alkylating agents or radiophorphours, as the latter agents are potentially leukemogenic.