ABSTRACT
BACKGROUND: Bone marrow mesenchymal stem cells have been extensively applied in animal experiments and clinical studies. The cell concentration, treatment times and results in each study are different, and there is no standard for optimal cell concentration. OBJECTIVE: To investigate the optimal concentration of bone mesenchymal stem cells injected into articular cavity in the treatment of rabbit cartilage defects. METHODS: Thirty 6-month-old New Zealand white rabbits were selected and randomly divided into control, 1×108, 1×109, 1×1010, and 1×1011/L groups. Cartilage defect models with diameter of 3 mm and depth of 2 mm were established in femoral trochlea in each group. One week after modeling, 1 mL of normal saline was injected into the rabbit’s knee of the control group. The other groups were injected with bone marrow mesenchymal stem cells at corresponding concentrations. After 6 and 12 weeks, gross observation, hematoxylin-eosin staining, Safranin-O-fast green-staining, type I and II collagen staining were performed to assess the cartilage regeneration. RESULTS AND CONCLUSION: In the control group, the defect area was obvious with no cartilage regeneration. The 1×108, 1×109, and 1×1010/L groups showed cartilage regeneration. The repairing effect was increased with the cell concentration increasing. The effect of cartilage repair in the 1×1011/L group was similar to that in the 1×1010/L group (P > 0.05). Therefore, 1×1010/L is the optimal concentration for intra-articular injection of bone marrow mesenchymal stem cells for treating cartilage defects, and higher concentration cannot enhance the repairing effect.
ABSTRACT
Background: Nowadays, leaching-ore bacteria, especially Acidithiobacillus ferrooxidans is widely used to retrieve heavy metals, many researches reflected that extra adding microorganism could promote bioleaching efficiency by different mechanisms, but few of them discussed the interaction between microorganisms and based on growth model. This study aimed to provide theoretical support for the collaborative bioleaching of multiple microorganisms by using the Lotka-Volterra (L-V) model. Results: This study investigated the interaction of Acidithiobacillus ferrooxidans, Rhizobium phaseoli,and Rhodotorula sp. Results showed that the individual growth of the three microorganisms fit the logistic curves. The environmental capacities of A. ferrooxidans, R. phaseoli, and Rhodotorula sp. were 1.88 x 109, 3.26 x 108, and 2.66 x 108 cells/mL, respectively. Co-bioleaching showed mutualism between A. ferrooxidans and R. phaseoli with mutualism coefficients of a =1.19and /3 = 0.31, respectively. The relationship between A. ferrooxidans and Rhodotorula sp. could be considered as commensalism. The commensalism coefficient y of the effect of Rhodotorula sp. on A. ferrooxidans was 2.45. The concentrations of A. ferrooxidans and R. phaseoli were 3.59 x 109 and 1.44 x 109 cells/mL in group E, respectively, as predicted by the model. The concentrations of A. ferrooxidans and Rhodotorula sp. were 2.38 x 109 and 2.66 x 108 cells/mL, respectively. The experimental peak values of the concentrations in microorganism groups E and F were detected on different days, but were quite close to the predicted values. Conclusion: The relationship among microorganisms during leaching could be described appropriately by Lotka-Volterra model between the initial and peak values. The relationship of A. ferrooxidans and R. phaseoli could be considered as mutualism, whereas, the relationship of A. ferrooxidans and R. phaseoli could be considered as commensalism.
Subject(s)
Rhodotorula/growth & development , Acidithiobacillus/growth & development , Rhizobium phaseoli/growth & development , SymbiosisABSTRACT
BACKGROUND: Recently, CD34 antigen expressed on hematopoietic stem cells which is not detected on non-Hodgkin lymphoma (NHL), multiple myeloma and most solid tumors, is identified. In autologous bone marrow transplantation (BMT), positive selection of CD34+ cells may be used to provide hematopoietic stem cells capable of engraftment but depleted of tumor cells. And it can be used to depletion of T lymphocytes to prevent the graft versus host disease (GVHD) in allogeneic BMT. So we performed this study to evaluate the efficacy of purification of CD34+ stem cells with CEPRATE SC Stem Cell Concentration System (CellPro Inc.) and to assess the influence of CD34+ stem cells on engraftment. METHODS: Peripheral blood stem cells were mobilized with cyclophosphamide (except one patient with malignant lymphoma) and G-CSF and harvested using CS-3000 (Fenwall). CD34+ stem cells counted by FACScan (Becton-Dickinson). The conditioning regimens were ICE (Ifosphamide/Carboplatin/Etoposide) in breast cancer, high dose melphalan in multiple myeloma, BEAC (BCNU/Etoposide/Ara-C/Cyclophosphamide) in NHL, TBI (total body irradiation) with cyclophosphamide in acute lymphocytic leukemia (ALL) and busulfan with cyclophosphamide in myelodysplastic syndrome (MDS). We used G-CSF (10 microgram/kg) after transplantation in all patients. RESULTS: Eleven patients, six with high risk or metastatic breast cancer, one with refractory multiple myeloma, one with acute lymphocytic leukemia (transformed from lymphoblasticlymphoma), two with relapsed malignant lymphoma, one with myelodysplastic syndrome (HLA one-locus mismatched allogeneic BMT case, for T lymphocyte depletion) were treated. Hematopoietic stem cells were harvested from autologous peripheral blood in all patients except one patient with MDS whose stem cells were harvested from allogeneic bone marrow. Median duration and number of peripheral blood stem cell (PBSC) harvest were 15 days (13~22) and 3 times (2~8), respectively. The mean number of total stem cells and CD34+ stem cells harvested per pheresis were 204.8 (17.4~797.9)x106/kg and 3.0 (0.3~11.9)x106/kg, respectively. The mean efficacy of CD34+ hematopoietic stem cell selection by CEPRATE SC Stem Cell Concentration System was 47.7% (1.4~99.0%). The number of infused CD34+ stem cells per patient ranged from 0.34 to 4.8x106/kg (mean 2.3x106/kg). After transplantation, the median day of achieving granulocyte counts of >0.5x109/L was 10.5 days and platelet counts of >50x109/L was 14 days. CONCLUSION: CD34+ stem cells separated with CEPRATE SC Stem Cell Concentration System provided reliable and timely hematopoietic reconstitution.