To investigate the expression of telomerase in cord blood hematopoietic stem/progenitor cells during their committed differentiation in vitro and provide an index of monitoring the proliferating potential of the hematopoietic stem/progenitor cells and security for clinical application. Human CD34 positive cells were isolated from umbilical cord blood by using magnetic cell sorting system (MACS), and were induced to differentiation with hematopoietic growth factors (SCF + IL3 + IL6 + GCSF and SCF + IL3 + IL6 + EPO) in a liquid culture system. The telomerase activity and the cytalytic subunit of telomerase (hTERT) of the cells were analysed during different periods of culture by using TRAP-PCR, TRAP-ELISA, Western blot and RT-PCR techniques, respectively. The results showed that a peak of cell growth was achieved on day 14 - 21 during induction of differentiation in vitro. Total cell number could increase 1006.4 +/- 103.2 times and could not increase there after. Telomerase activity and hTERT expression were low in freshly isolated cord blood CD34(+) cells and increased after about 7 days of culture in addition of cytokine combinations of SCF + IL3 + IL6 + GCSF and SCF + IL3 + IL6 + EPO, respectively. The telomerase activity and hTERT decreased after 14 days of culture and were not detected after 28 days of culture. It was concluded that the hematopoietic stem/progenitor cells can be expanded in large number in vitro and do not have the character of immortality and the telomerase activity could be a useful index in hematopoiesis regulation.

To investigate the expression and function of the receptors of early-acting cytokines on cord blood CD34(+) hematopoietic stem/progenitor cells, the studies of Flt3 and c-kit were undertaken at the gene and protein levels. Fresh and cultured cord blood CD34(+) stem/progenitor cells were analyzed by flow cytometric two-color direct immunofluorescence methods and RT-PCR, while function of receptors was studied in vitro. It was found that (68.8 +/- 15.4)% of CD34(+) cells expressed Flt3, (50.6 +/- 12.7)% of CD34(+) cells expressed c-kit, the proportion of CD34(+) cells expressing Flt3 and c-kit decreased as in vitro culture time extended. It was concluded that cord blood CD34(+) stem/progenitor cells are capable of expressing Flt3 and c-kit for as long as 2 - 3 weeks in liquid medium, during the first week of culture, SCF and FL enhanced the generation of cells and progenitors notably.

Mesenchymal stem cells possess the ability to differentiate into osteoblasts, chondroblasts, lipoblasts, myoblasts and so on, which can be used in the formation of hematopoietic microenvironment, tissue repairing and gene therapy. Growth factors such as TGF-beta, IGF-I, BMP and FGF can influence on the differentiation of MSC and they cooperate with each other. MSCs support hematopoiesis by secreting cytokines including G-CSF, SCF, LIF, M-CSF, IL-6, IL-11 and are related to some diseases. MSC would demonstrate important effect on gene engineering.

To investigate the relationship between interleukin-18 (IL-18) and human acute graft-versus-host disease (aGVHD), 26 patients undergoing allogeneic peripheral blood stem cell transplantation (allo-PBSCT) were included in this study. IL-18 secreted by peripheral blood mononuclear cells (MNCs) was measured by enzyme-linked immunosorbent assay (ELISA) before transplantation and during aGVHD. The results showed that grade I GVHD and grades III-IV GVHD developed in 10 and 5 cases, respectively. The levels in the supernatants of MNCs from patients with aGVHD were significantly higher than those in the cases without aGVHD. The levels of IL-18 were correlated with the severity of aGVHD. It is concluded that IL-18 plays an important role in the development of aGVHD.

Using a fluorochrome Calcein-AM, leukemia cells were labeled and seeded into cell lines or bone marrow cells to establish three cell-models of grafts with leukemia. These cell-models were engaged with CD34 immunomagnetic beads and the purging efficacy was evaluated using both fluorescence microscopy and flow cytometry. The results showed that the cell-models established in this study could be evaluated successfully not only with fluorescence microscopy but also flow cytometry. After CD34 positive selection, KG1a cells were removed by (0.98 +/- 0.09) log in model II and NALM-6 cells were removed by (1.82 +/- 0.51) log in model III, respectively. It is concluded that the models established in this study are stable and direct with an excellent reproducibility and an accuracy, which can be used to evaluate purging efficacy of leukemia cells in model graft using immunomagnetic selection and the experimental studies on tumorcidal effect in vitro.

The stem cell leukemia (SCL) gene is a new oncogene related with leukemogenesis. To explore the effects of antisense oligonucleotides of SCL on leukemic cells, SCL antisense phosphorothioate oligodeoxynucleotides (AS-PS-ODN) were used to treat K562 and CEM leukemic cell lines to observe the effects on proliferation, differentiation, apoptosis and SCL mRNA expression in the cells. The results showed that incubation of K562 or CEM cells with AS-PS-ODN at different concentrations led to inhibition of cell proliferation, and the inhibitory effects varied with the incubation time. The positive rate of benzidine staining in K562 cells increased significantly after the inhibition with AS-PS-ODN, compared with S-PS-ODN treatment. The characteristics of apoptosis were observed in K562 cells treated with AS-PS-ODN, but not in CEM cells. Expression of SCL mRNA in K562 and CEM cells and SIL-SCL mRNA in CEM cells decreased after incubation of AS-PS-ODN. It is concluded that SCL AS-PS-ODN inhibits specifically the proliferation of K562 and CEM cells, also decreases the level of SCL and SIL-SCL mRNA expression. AS-PS-ODN enhances erythroid differentiation and induces premature apoptosis in K562 cells.

The biological characterization, differentiation and regeneration of hepatic stem/progenitor cells are the one of very active and interested fields. In this report, intravenous injection of human umbilical cord blood (HUCB) cells into the BALB/c-nu and SCID mice, an animal model for transplantation and liver injury, was reported. Using of flow cytometry and tissue typing (HLA), it was found that the HUCB cells were survived in mouse liver for 9 weeks. After separation from perfused liver, HUCB cells were detected by hematopoietic colonies (CFU-GEM M) in hepatocyte culture. It was concluded that the transplanted HUCB hematopoietic stem/progenitor cells can be survived in the liver over a long period of time.

To elucidate the effect of established primary bone marrow stromal layers on the gene transduction of human hematopoietic stem/progenitor cells (HSC/HPC), mononuclear cells (MNC) from adult bone marrow were isolated by centrifugation on Ficoll-Hypaque gradients and plated in stromal culture medium. The cells were incubated until passage 4 to establish primary stromal layers. The HSC/HPC prestimulated by cytokines were transduced by retroviral supernatant containing mdr1 gene in presence of irradiated stroma-contact support. Transduced cells were plated in a colony-forming unit assay with and without vincristine (VCR) to assess the efficiency of transduction. Individual colonies were also analyzed by polymerase chain reaction (PCR) for the presence of provirus. The results showed that the mixed adherent cell layers were formed when adult bone marrow stromal cells were incubated for four to six weeks, mainly being composed of fibroblasts. In the presence of stroma-contact support, the average of gene transduction efficiency in marrow-derived progenitors increased 2.1 to 3.3 folds measured by colony-forming assay and/or PCR, significantly higher than those without support of stroma. It is concluded that the presence of bone marrow stroma support in combination with cytokine facilitates augmenting the extent of retroviral-mediated gene transduction.

To observe whether bone marrow stromal cell line QXMSC1 (H-2(d)) engineered to secrete IL-3 and IL-6 can improved the hematopoiesis in allogeneic bone marrow transplantation (allo-BMT) mice, the stromal cell line QXMSC1IL-3/IL-6 was established by QXMSC1 cells transduced with the recombined retrovirus vector pL3SN containing mouse IL-3 cDNA and pL6SN containing human IL-6 cDNA. The lethally irradiated C57BL/6 (H-2(b)) mice were engrafted with bone marrow cells (1 x 10(7) cells/mouse BALB/c mice, H-2(d)) in which T cells were depleted by anti-Thy1.2 monoclonal antibody adding complement, and QXMSC1IL-3/IL-6 cells (5 x 10(5)/mouse) were co-infused at same time. The hematopoiesis of recipient mice was observed in 20 and 40 days post-transplantation. Blood RBC and WBC were counted, and nucleated cells, CFU-S, CFU-GM, CFU-E and CFU-GEMM were assayed in recipient bone marrow. Results showed that IL-3 and IL-6 were stably expressed in QXMSCQIL-3/IL-6 cells. Compared with BMT and co-infusion with QXMSC1 or QXMSC1 pLXSN cell groups, co-graft with QXMSC1IL-3/IL-6 cells increased the number of blood RBC and WBC in the recipients, and also significantly increased nucleated cells, CFU-S, CFU-GM, CFU-E and CFU-GEMM in recipient bone marrow. It is concluded that the marrow stromal cells transduced with IL-3/IL-6 cDNA improve the hematopoiesis in allo-BMT mice. Co-graft with QXMSC1IL-3/IL-6 cells has synergistic effect in accelerating hematopoietic reconstitution.

This study was undertaken to establish a murine model for unrelated allogeneic umbilical cord blood transplantation (UCBT). The characteristics and percentage of hematopoietic stem/progenitor cells between near-term fetal and neonatal murine peripheral blood (FNPB) and bone marrow (BM) were evaluated by flow cytometry and semisolid methylcellulose culture. BABL/c (H-2(d)) recipient mice conditioned with high dose CTX were transplanted with FNPB form C57BL/6 (H-2(b)) mice and the survival rate, hematopoietic and immunological reconstruction, graft versus host disease (GVHD) and engraftment level were observed. The results showed that the numbers of day 14 CFU-GM and CFU-GEMM in FNPB (176.40 +/- 78.39)% and (141.40 +/- 56.57)%, respectively were much higher than those in BM (75.20 +/- 26.41)% and (68.80 +/- 23.95)%, respectively. Moreover the percentage of Sca-1(+) CD34(+) cell subsets in FNPB (3.63 +/- 1.13)% was also higher than that in BM (1.41 +/- 0.8 7)%. FNPB transplantation improved survival rate and reconstituted hematopoietic and immune function in recipients. There was no evidence of GVHD. Chimeric analysis showed that the proportion of donor cells in BM of recipients was 27.94% at 21 days after transplantation. It was concluded that FNPB contains more hematopoietic stem and progenitor cells with high expansion ability and weak allogeneic immunity, which was similar to human UCB. The murine model for allogeneic UCBT (C57BL/6-->BALB/c) was established successfully.

The purpose of this study is to explore the clinical significance of RBC blood group serological test in nonmyeloablative allogeneic peripheral blood stem cell transplantation (NAPBSCT) of ABO group incompatibility in 4 patients with acute leukemia. ABO and MN blood group of donors and recipients were determined by hemagglutination test and Rh blood group by Diana Gel phenotype Rh card. The changes of blood group in recipients were observed and implant of donor cells was monitored by short tandem repeat-PCR method. The results showed that in 2 cases of 4 recipients the marrow cells appeared mixed chimera of donor and recipient cells, and blood group changed to donor type in 1 of the 2 cases on 100 days after transplantation. In another 2 cases, the marrow cells appeared mixed chimera without blood group chimera on 154 days after transplantation, and rejection of the transplant occurred in 1 of the 2 cases. The determination of hemagglutinin titer showed that the implant rate of donor cells was lower in the recipients with higher hemagglutinin titer and blood group chimera did not appear, conversely, the implant rate was higher in the recipients with lower titer and blood group chimera appeared early. It is concluded that examination of RBC blood group in NAPB SCT can indirectly reflect effectiveness of transplantation, contribute to decide the intensity of conditioning protocol and immunosuppressive therapy after transplantation, estimate prognosis and guide blood transfusion during transplantation.

In order to understand the effect of hematopoietic stem cell mobilization agents, G-CSF and GM-CSF, on the expression of TNF-alpha mRAN and CD69 and secretion of IgG in SLE patients' peripheral blood mononuclear cells (PBMNC), expression of TNF-alpha mRNA and CD69 was measured by RT-PCR and flow cytometry, respectively, and IgG secretion by ELISA. The results showed that 0.1 - 2.0 microg/ml G-CSF did not affect the expression of TNF-alpha mRNA in active and static patients' PBMNC treated with 0.1 - 2.0 microg/ml cytokines, and 2.0 microg/ml GM-CSF increased the expression of TNF-alpha mRNA in active patients' PBMNC. G-CSF and GM-CSF did not interfere the expression of CD69 in active and static patients' PBMNC, however, the expression of CD69 was significantly increased in active patients' PBMNC treated with GM-CSF at more than 8 microg/ml. There was no obvious change of IgG secretion from PBMNC induced with 10 microg/ml G-CSF, while the IgG secretion was stimulated by 10 microg/ml GM-CSF. It was concluded that G-CSF as a mobilization agent could be safe to SLE patients, but GM-CSF may cause some harmful effects to patients because of the increase of the parameters relating to activity of lupus in active SLE patients.

To compare the expression of CD antigens on immune cells from umbilical cord blood (UCB) and bone marrow (BM) and analyze its clinical significance, the phenotypes of lymphoid cells and nucleated cells from 38 UCB and 10 BM samples were investigated by flow cytometry with double labeling monoclonal antibodies. The results showed that the immature lymphocytes (CD3(-) CD4(+)) were detected in UCB and higher than those in BM; cytotoxic T lymphocytes (CD3(+) CD16(+) CD56(+)) in UCB were significantly lower than those in BM. NK cells (CD3(-) CD16(+) CD56(+)) in UCB were higher than those in BM. The ratio of CD34(+) cells in nucleated cells of UCB was similar to that of BM, however, both the contents of myeloid (CD34(+) CD13(+) and CD34(+) HLA-DR(+)) and lymphoid (CD34(+) CD19(+)) progenitor cells in UCB were lower than those in BM. It is concluded that the immune cells in UCB possess immaturity, which might lead to mild GVHD after UCB transplantation. It is inferred from the higher ratio of NK cells in UCB, GVL will not decrease after UCB transplantation. The lower contents of myeloid and lymphoid progenitor cells in UCB probably accounted for the slow hematopoiesis and immune reconstitution following UCB transplantation.

To explore the effect of retinoic acid (RA) on the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in murine bone marrow stromal cell (BMSC) and adhesive rate of human cord blood mononuclear cell (UCBMNC) to BMSC in vitro, the express ions of ICAM-1 and VCAM-1 of murine BMSC were detected by flow cytometry and the binding capacity of UCBMNC to BMSC was tested by MTT assay after co-culturing with 0.1, 1.0 and 10.0 micro mol/L RA, respectively. The results showed that 1.0 and 10.0 micro mol/L RA increased the expression of ICAM-1 and the adhesive rate of U CBMNC to BMSC, however, RA did not induced the increase of expression of VCAM-1. It was positive correlation between the increments of ICAM-1 expression and the adhesive rate (r = 0.7883, P < 0.05). It is concluded that RA up-regulated ICAM-1 expression of BMSC and increased the adhesion of UCBMNC to BMSC in vitro. These may clarify the correlation between adhesion molecules on BMSC and homing of hematopoietic stem cells, and provide the experimental basis for RA to promote the homing of umbilical cord blood stem cell.

To evaluated the feasibility of preventing infection after high dose chemotherapy and radiotherapy using the granulocytes derived from differentiated from hematopoietic stem/progenitor cells ex vivo, human CD34-positive cells were isolated from umbilical cord blood by using a high-gradient magnetic cell sorting system (MACS), and the cells committedly differentiated with hematopoietic cytokines (SCF + IL-3 + IL-6 + G-CSF) in a liquid culture system. The expanded cell number, ratio of the viable cells, chromosome and phenotype of the differentiated cells and safety analysis of expanded cells were detected by using cell count, trypan blue exclusion test, karyotype analysis, flow cytometry and tumorigenic model of nude mice, respectively. The results showed that the combination of cytokines increased cell number by (1006.4 +/- 103.2) folds and flow cytometric analysis showed myeloid marker CD11b expressed in the about 60% cells. The growth peak of differentiated cells was at 14 days of culture and decreased at about 33 days. No abnormality was found in the karyotype analysis of expanded cells. No tumor was found in the nude mice injected with expanded cells after 35 days and the expanded cells had the ability of phagocytizing bacteria. It is concluded that the cells, differentiated from CD34(+) cells, expanded ex vivo possess the function of granulocyte and it was safe for clinical trial.

In this study, the roles of hematopoietic inhibitors elaborated by bone marrow endothelial cells in the proliferation and differentiation of hematopoietic progenitors were investigated. Murine bone marrow endothelial cell conditioned medium (BMEC-CM) was collected and the components with > 10 kD and < 10 kD were obtained by centrifugal ultrafiltration. The effect of BMEC-CM and its components on proliferation of hematopoietic progenitors was evaluated by CFU-GM and HPP-CFC assay and antibody neutralization test. The expression of the inhibitors in BMEC and BMEC-CM was detected by RT-PCR and Western blot, and change of proliferation and differentiation-related genes during expansion of hematopoietic progenitors was examined by membrane hybridization technique.

To study the possibility that induced marrow stromal cells (MSCs) to neuron in vitro by baicalin, a kind of flavonoid isolated from an important medicinal plant Scutellariae Radix.

To investigate the effect of transfection of 5-aza cytidine (5-aza) induced BMSCs that were transfected with Ad. ANG ex vivo into infarcted myocardium.

To establish embryonic stem (ES) cell lines from human fertilized ovum in China.

To study the feasibility and clinical outcome of granulocyte-colony stimulating factor (G-CSF) mobilized allogeneic bone marrow (G-BM) plus G-CSF mobilized peripheral blood stem cells (G-PBSC) transplantation for malignant hematological disease.