BackgroundSpeciation of arsenic trioxide (ATO) metabolites in clinical samples such as peripheral blood (PB) from acute promyelocytic leukemia (APL) patients has been conducted. However, speciation of arsenicals in bone marrow (BM) has not yet been performed. Profiles of arsenic speciation in plasma of BM were thus investigated and compared with those of PB plasma from a relapsed APL patient. The total arsenic concentrations in high molecular weight fraction (HMW-F) of BM and PB plasma were also determined.MethodsResponse assessment was evaluated by BM aspirate examination and fluorescence in situ hybridization analysis. The analyses of total arsenic concentrations and speciation were preformed by inductively coupled plasma mass spectrometry (ICP-MS), and high-performance liquid chromatography (HPLC)/ICP-MS, respectively.ResultsResponse assessment showed that the patient achieved complete remission. The total arsenic concentrations in BM plasma increased with time during the consecutive administration. The PB plasma concentrations of methylated arsenic metabolites substantially increased after the start of administration, while those of inorganic arsenic were still kept at a low level, followed by substantially increase from day-14 after administration. The arsenic speciation profiles of PB plasma were very similar to those of BM plasma. Furthermore, the total arsenic concentrations of HMW-F in BM plasma were much higher than those in PB plasma.ConclusionsThe behaviors of arsenic speciation suggested for the first time that arsenic speciation analysis of PB plasma could be predicative for BM speciation, and showed relatively higher efficiency of drug metabolism in the patient. These results may further provide not only significance of clinical application of ATO, but also a new insight into host defense mechanisms in APL patients undergoing ATO treatment, since HMW proteins-bound arsenic complex could be thought to protect BM from the attack of free arsenic species.
Hematopoiesis occurs in the bone marrow, where primitive hematopoietic cells proliferate and differentiate in close association with a three-dimensional (3D) hematopoietic microenvironment composed of stromal cells. We examined the hematopoietic supportive ability of stromal cells in a 3D culture system using polymer particles with grafted epoxy polymer chains. Umbilical cord blood-derived CD34(+) cells were co-cultivated with MS-5 stromal cells. They formed a 3D structure in the culture dish in the presence of particles, and the total numbers of cells and the numbers of hematopoietic progenitor cells, including colony-forming unit (CFU)-Mix, CFU-granulocyte-macrophage, CFU-megakaryocyte and burst-forming unit-erythroid, were measured every seven days. The hematopoietic supportive activity of the 3D culture containing polymer particles and stromal cells was superior to that of 2D culture, and allowed the expansion and maintenance of hematopoietic progenitor cells for more than 12 weeks. Various types of hematopoietic cells, including granulocytes, macrophages and megakaryocytes at different maturation stages, appeared in the 3D culture, suggesting that the CD34(+) cells were able to differentiate into a range of blood cell types. Morphological examination showed that MS-5 stromal cells grew on the surface of the particles and bridged the gaps between them to form a 3D structure. Hematopoietic cells slipped into the 3D layer and proliferated within it, relying on the presence of the MS-5 cells. These results suggest that this 3D culture system using polymer particles reproduced the hematopoietic phenomenon in vitro, and might thus provide a new tool for investigating hematopoietic stem cell-stromal cell interactions.
Objective Bacillus cereus (B. cereus) septicemia is a cause of life-threatening infection in patients with hematologic diseases. However, preventing a fatal prognosis in patients with B. cereus infection has not yet been achieved due to insufficient clinical investigations. To discover more optimal treatment strategies, we analyzed B. cereus septicemia in patients with hematologic diseases. Methods At our institution, we observed 13 cases of B. cereus septicemia in 12 patients with hematologic diseases between January 2001 and September 2010. The susceptibility of B. cereus strains to antibiotics was also analyzed. Results Of 12 patients, four died of B. cereus septicemia. In this study, the delayed administration of appropriate antibiotics (starting >24 hours after presentation), the presence of liver dysfunction and evidence of central nervous system (CNS) involvement tended to result in a fatal prognosis. All of the bacterial strains were found to be susceptible to vancomycin and quinolones (such as ciprofloxacin and levofloxacin), whereas many strains were resistant to clindamycin (76.9%) and imipenem (30.8%). In seven of 10 patients, central venous (CV) catheter tips were removed and routinely cultured. Catheter tip cultures were positive for B. cereus in three of seven patients. Conclusion Although not specific to B. cereus bacteremia, patients who died of B. cereus tended to present with CNS symptoms and/or liver dysfunction. Our clinical data suggested that carbapenem and clindamycin are no longer appropriate choices for treating B. cereus. In addition, B. cereus septicemia was found to frequently originate from CV catheters. Constant attention must be paid to update assessments of antibiotic susceptibility and careful management must be applied to CV catheters in patients with hematologic diseases.
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