To evaluate the effect of imatinib mesylate (STI571) on primitive/committed malignant progenitor cells in chronic myelogenous leukemia (CML) and to further elucidate the mechanisms involved in CML relapse and in some CML cells resistant to STI571, bone marrow-derived malignant bcr/abl-positive, Flk1(+)CD31CD34(-) cells with hemangioblastic characteristics from CML patients were grown in Methocult GF+ media with or without STI571, and inhibitory effect of STI571 on proliferation of differentiated and differentiating, bcr/abl(+), Flk1(+)CD31CD34(-) cells with hemangioblastic characteristics was investigated in vitro. The results showed that in vitro exposure to 5 micromol/L STI571 (the concentration of STI571 usually achieved in patients is 1-2 micromol/L) for 96 hours inhibited bcr/abl(+) committed progenitors (colony-forming cells, CFCs). No evident suppression of normal primitive, bcr/abl(+), and Flk1(+)CD31(-)CD34(-) cells were observed. It is concluded that CML primitive stem cells remain viable in the presence of STI571 and that inhibition of bcr/abl tyrosine kinase by STI571 restores normal hematopoiesis by removing the proliferative advantage of CML committed progenitors but that elimination of all CML progenitors may not occur. So despite dramatic short-term responses in vivo, such in vitro resistance to STI571, may translate into disease relapse after prolonged therapy.

To investigate the purging effect of CD3AK/iNOS on primary leukemic cells from chronic myeloid leukemia patients in vitro, amphotropic packaging cell line PA317 transfected with the whole length of iNOS gene was cultivated, amplified and screened by G418. The viral titer was determined by the NIH3T3 cells. Human peripheral blood mononuclear cells were isolated and activated by anti-CD3 monoclonal antibody in vitro. CD3AK cells were incubated with viral supernatant and selected by G418. Resistant clones were assayed for iNOS gene expression by RT-RCR. The content of nitric oxide and the activity of iNOS in the culture supernatant of CD3AK/iNOS were evaluated by the method of Griess. After BMMNC or PBMNC from CML patients were co-cultured with CD3AK/iNOS, CD3AK/Neo and CD3AK/iNOS respectively, the expression of bcr/abl fusion gene was detected by serial dilution semi-quantitative net RT-PCR assay. The results showed that anti-G418 positive packaging cell line PA317 transfected with the whole length of iNOS gene clones could stably synthesize and excrete recombinant retroviral vectors. The titer of recombinant retroviral vectors was 1.0 x 10(5) CFU/ml. After being transfected by recombinant retroviral supernatant, the iNOS cDNA was expressed in CD3AK/iNOS. The content of NO and activity of iNOS that synthesized and excreted by CD3AK/iNOS were notably increased, compared with those of CD3AK. There were statistically significant differences in NO content and iNOS activity between two groups. After BMMNC or PBMNC from CML patients were co-cultured with CD3AK/iNOS, CD3AK/Neo and CD3AK/iNOS respectively, the expression of bcr/abl fusion gene in all of them was down-regulated by serial dilution semi-quantitative RT-PCR assay. It is concluded that construction of CD3AK/iNOS can markedly increase the content of NO and the activity of iNOS, which can be more efficient in in vitro purging leukemia cells for autologous hematopoietic stem cell transplantation.

The purpose of this study is to investigate the influence of enamel matrix proteins(EMPs) on the attachment, spreading and proliferation of cultured porcine bone marrow stromal cells (BMSCs).

The culture of human spermatogonial stem cells (SSC) has not been studied in detail yet. Here we tried to explore the optimized culture method of human SSC by using several different co-culture systems.

Stem cell can both self-renew and have the ability to differentiate into one or more cell types that perform normal tissue/organ function throughout life, including embryonic stem cell and adult stem cell. The treatment with stem cells will be widely used in the future. This article reviews recent advances in studies of the use of embryonic stem cells and spermatogonial stem cells in male reproduction.

To investigate the occurrence of immunological rejection in brain transplantation of neural stem cells (NSCs) in the rat of Parkinson's disease model.

To investigate the effects of ex-vivo expansion on proliferative ability, pluripotentiality and other biologic characteristics of human bone marrow mesenchymal stem cells(MSCs).

We undertook a series of studies to evaluate the role of microenvironment during embryonic stem cell (ESC) proliferation and differentiation. In this paper, cell microencapsulation technology was employed, which allows the free exchange of nutrients, oxygen and biologically active products between the entrapped cell and culture medium. We analyzed the feasibility of mouse ESCs in microcapsules and evaluated the growth, metabolic activity and differentiation of ESCs once enclosed in alginate-Ca(2+) microbead, solid or liquefied core alginate-poly-lysine-alginate (APA) microcapsule, respectively. We found that ESCs grew gradually in both types of microcapsules, but the appearance of cells was distinctive for each type of capsule. In the case of unliquefied microcapsules, cells created multiple spherical or lens-shaped aggregates. In contrast, the liquefied alginate core allowed the enclosed ESCs to grow together in a clump at the periphery of the capsule. Combined with cell viability and activity of glucose/lactic acid metabolism, the liquefied core of APA might provide more suitable culture conditions for the ESC growth in comparison with the unliquefied type or alginate-Ca(2+). For better evaluating the nature of ESC growth in APA microcapsules in vitro (that is whether or not encapsulated ESCs maintained undifferentiated state while they kept the ability for proliferation), the expression of the typical markers for undifferentiated, dividing ESCs, such as the stage specific embryonic antigen (SSEA-1) and alkaline phosphatase (AP), was detected by immunochemistry and immunofluorescence staining. The results showed that cell aggregates formed in the microcapsule still expressed the marker proteins at a higher level on day 22 in vitro. The expression of gene Oct-4, a transcription factor necessary for maintaining ESCs in an undifferentiated state, was also detected when RT-PCR assay was employed (on day 22 in vitro). In addition, cell aggregates were released from the microcapsules by mechanical disruption and induced into insulin-producing cells. These findings further indicate that most of the ESCs in APA microcapsule maintain their multi-potential even though the culture time prolonged as long as 22 d in vitro. Taken together, APA microcapsule provides a suitable microenvironment that promotes ESCs to maintain their stemness. Therefore, the microenvironment plays an important role in the process of ESC proliferation and differentiation.

To evaluate the practicability of cartilage reconstruction using directed inducing bone marrow stem cells(MSCs)- alginate complex.

To examine the effect of salidroside on bone marrow cell cycle and expression of apoptosis-related proteins in bone marrow cells (BMCs) of bone marrow depressed anemia mice, and to explore its mechanism for hematopoietic regulation.

To detect the integration and expression of porcine endogenous retrovirus (PERV) in the immortal cell line of Banna Minipig Inbred Line-Mesenchymal Stem Cells (BMI-MSCs).

To explore morphological recellularization level of bioprosthetic valve scaffold (BVS) and to provide researching means for fabricating tissue engineered heart valve in vitro.

To investigate the effect of dexamethasone, recombinant human fibroblast growth factor (rhFGF) and recombinant human bone morphogenetic protein 2 (rhBMP-2) on the proliferation and differentiation of marrow stromal stem cells (MSCs) for their further application in tissue engineering.

Leydig cells are the primary source of testosterone. As is true for all specialized cells, Leydig cells originally arise from primitive undifferentiated stem cells, stem Leydig cells (SLCs). The huge potential of SLCs is to be used therapeutically to restore testosterone levels in males with androgen deficiency due to diverse causes. The initial paradigm for cell therapy would call for harvesting the SLCs of an androgen deficient male, amplifying these cells in vitro, inducing differentiation in vitro, and then implanting the mature Leydig cells back into the same individual.

To investigate the possibility of reconstruction of dentin-pulp complex by tissue engineering technology.

To observe the effect of connective tissue growth factor (CTGF) on the transdifferentiation of human renal tubular epithelial cells and to explore the influence of CTGF antisense oligodeoxynucleotide (ASODN) transfection on the transdifferentiation process induced by transforming growth factor-beta1 (TGF-beta1).

To evaluate whether mesenchymal stem cells (MSCs) obtained from human proximal femurs possess immunosuppressive effect so as to look for ideal bank of MSCs for clinical prophylaxis and treatment of graft versus host disease (GVHD).

To investigate the preparation method of porcine bladder acellular matrix graft (BAMG) and evaluate the feasibility of using BAMG as biomaterial scaffold to construct tissue engineering bladder.