RESUMO
Constructing heterojunction is an attractive strategy for promoting photoelectrochemical (PEC) performance in water splitting and organic pollutant degradation. Herein, a novel porous BiVO4/Boron-doped Diamond (BiVO4/BDD) heterojunction photoanode containing masses of ultra-micro electrodes was successfully fabricated with an n-type BiVO4 film coated on a p-type BDD substrate by magnetron sputtering (MS). The surface structures of BiVO4 could be adjusted by changing the duration of deposition (Td). The morphologies, phase structures, electronic structures, and chemical compositions of the photoanodes were systematically characterized and analyzed. The best PEC activity with the highest current density of 1.8 mA/cm2 at 1.23 VRHE was achieved when Td was 30 min, and the sample showed the highest degradation efficiency towards tetracycline hydrochloride degradation (TCH) as well. The enhanced PEC performance was ascribed to the excellent charge transport efficiency as well as a lower carrier recombination rate, which benefited from the formation of BiVO4/BDD ultra-micro p-n heterojunction photoelectrodes and the porous structures of BiVO4. These novel photoanodes were expected to be employed in the practical PEC applications of energy regeneration and environmental management in the future.
Assuntos
Bismuto , Vanadatos , Bismuto/química , Boro , Diamante , Porosidade , Vanadatos/químicaRESUMO
OBJECTIVE: To explore the hematopoietic reconstitution potential of mesenchymal derived stem like cells. METHODS: We transplanted bone marrow mesenchymal derived stem like cells into lethally irradiated BALB/c mice. Hematopoietic cells were derived from the non-adherent bone marrow cells 24 hours after initial culture while murine mesenchymal derived stem like cells from bone marrow of donor mice were cultured for 10 days before the transplantation. RESULTS: All mice of group 1 and 3 died in 7-8 days post irradiation following transplantation, while all the mice from group 2 and 4 survived. The time course of hematopoietic reconstitution was then observed. The peripheral blood and bone marrow cell count recovered in the MSC + G-CSF transplanted group and the BM transplanted group after 3 weeks. Interestingly, CFU-GM number in the MSC + G-CSF transplanted group increased significantly after 2 weeks and even more than that in the BM transplanted group after 3 weeks while as CFU-GM colony dropped 2 weeks after in the BM transplanted group. Spleen colony (CFU-S) number and size of the MSC + G-CSF transplanted group was significantly greater than the BM transplanted group. Furthermore, PCR analysis was performed using peripheral blood cells to determine if any male-derived cells were present. No male-derived cells were found in any of the mice from group 1 and 3. Y-chromosome-specific src gene was found to be dominant in the MSC + G-CSF transplanted group and the BM transplanted group by week 4 post transplantation. In addition, we demonstrated that induction with G-CSF lead to CFU-GM colony formation from MSC compartment in vitro. CONCLUSION: These results indicate that under stimulation of G-CSF, mesenchymal derived stem like cells might differentiate into hematopoietic primitive stem cells in vivo and have the capacity to re-establish hematopoiesis in lethally irradiated mice. This study should provide an alternative transplantation treatment for malignancy.
Assuntos
Fator Estimulador de Colônias de Granulócitos e Macrófagos/administração & dosagem , Hematopoese/efeitos dos fármacos , Células-Tronco Hematopoéticas/citologia , Transplante de Células-Tronco , Animais , Transplante de Medula Óssea , Células Cultivadas , Feminino , Hematopoese/efeitos da radiação , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Lesões Experimentais por Radiação , Protetores contra Radiação/administração & dosagem , Irradiação Corporal TotalRESUMO
OBJECTIVE: To isolate and identify the phenotype and biological characteristics of pancreas derived mesenchymal stem cell. METHODS: Fresh pancreas of 4-5 months old aborted fetus was dissected free from connective tissue, and was cut into small pieces. The adherent cells were harvested and subcultured, after the third subculture, the cells were used for examination. Cell cycle was analyzed by measuring DNA content by FACScan flow cytometer. Phenotype of MSCs was analyzed by immunohistochemical SA technique and differentiated cells were identified by relevant specific staining. RESULTS: Fetal pancreas derived cells gave rise to a population of adherent cells characterized by the presence of a predominant cell type with a typical fibroblast like morphology. By transmission electron microcopy, MSC had few endoplasmic reticulums and mitochondrias. During the log phase of growth, MSC proliferated with a two fold population at 30 h. MSC can be ex vivo expanded by successive cycles of trypsinization, seeding, and culture. Under these conditions, MSC had capability of passaging up to 30 times without displaying significant changes in morphology, with 2-fold increase in cell number after each passage. This indicates the high ex vivo expansion potential of MSC. The results showed that the yield of CFU-Fs was above 200 clones even after the 6th passage. Cell cycle analysis by flow cytometry revealed that more than 83% of cells were in the G0/G1 phases, while a small population of cells were actively engaged in proliferation (S + G2 + M = 17%). We also showed that more than 86% of cells were positive stained by FITC labeled CD44, CD29, CD13, and only about 1% of cells were positive for CD34, HLA-DR. Expression of collagen I, III was positive while vWF was negative. In the differentiation study, we found culture-expanded pancreas MSCs could be directed into the osteogenic lineage as detected by osteoblastic morphology, expression of alkaline phosphatase, modulation of osteocalcin mRNA production and the formation of a mineralized extracellular matrix. We also found that MSCs could give rise to the adipogenic and chondrogenic lineage as evidenced by accumulation of lipid-rich vacuoles within cells and the expression of lipoprotein lipase mRNA or the expression of collagen II and the deposition of proteoglycans. CONCLUSION: Mesenchymal stem cells existing in human pancreas can be isolated by their adherent ability and should be essential to sustain a steady supply of primitive cells in tissue remodeling.
Assuntos
Osteogênese , Pâncreas/citologia , Células-Tronco/citologia , Diferenciação Celular , Divisão Celular , Separação Celular , Células Cultivadas , Ensaio de Unidades Formadoras de Colônias , Feto , Fibroblastos/citologia , Humanos , Mesoderma/citologia , FenótipoRESUMO
OBJECTIVE: To study the characteristics of dermal mesenchymal stem cells (DMSC), and explore whether they could enhance hematopoiesis recovery in vivo as well as facilitate proliferation and differentiation of hematopoietic cells in vitro. METHODS: Multipotential stem cells from the murine dermal mesenchyme were dissociated and cultured as donor cells. After 2 approximately 3 passages, the growth status, cell cycle, immunophenotype and morphology of DMSC were analyzed. Hematopoietic cells were plated onto a feeder layer formed by DMSC, cell count and CFU-GM yields were observed dynamically. Female mice received 5 Gy (137)Cs radiation were injected with DMSC cultured for 2 - 3 passages via tail vein. Cell count and CFU-GM yields of the bone marrow were observed regularly. Pathological study of the liver, spleen and bone marrow was done to evaluate hematopoiesis recovery. RESULTS: Murine DMSC are adherent cells with a morphology of fibroblastoid and spindle and multiangle in shape. Immunophenotypes showed that CD(45), CD(34), HL-DR positive DMSC were 1 - 3%, CD(44) and CD(13) positive DMSC 75 approximately 95%. Cell cycle assay demonstrated 83% of DMSC being G(0)/G(1) phase. In vitro, the total cell count and CFU-GM yields in the experimental group were higher than those of the long-term culture bone marrow cells by the third week. The DMSC can sufficiently support the proliferation and differentiation of hematopoietic cells for seven weeks. In vivo, peripheral granulocytic count, cells in the bone marrow of one femoral bone and CFU-GM by the third week in the experimental group were much higher than those of controls. Genetic assay of the murine blood demonstrated Y chromosome. CONCLUSION: The DMSC have characteristics of stem cells. DMSC sped up hematopoiesis recovery of irradiated mice. DMSC as a feeder layer can support proliferation and differentiation of hematopoietic cells.
Assuntos
Hematopoese , Mesoderma/citologia , Pele/citologia , Células-Tronco/fisiologia , Animais , Transplante de Medula Óssea , Feminino , Imunofenotipagem , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Transplante de Células-TroncoRESUMO
OBJECTIVE: To explore the differences of phenotype and biological characteristics between fetal and adult bone marrow derived mesenchymal stem cells. METHODS: Mononuclear cells from 4-5 months old human aborted fetus and normal adult bone marrow were cultured in SF medium to obtain mesenchymal stem cells. The growth curve, cell cycle, immunophenotype, in vitro expansion potential, differentiation capacities were investigated. RESULTS: The adherent fetal and adult bone marrow-derived cells cultured in the absence of differentiation stimuli gave rise to a population of cells with phenotypical features of mesenchymal stem cells (MSC). These MSCs were similar in cell morphology and antigenic phenotype. The proliferative and multilineage differentiation potential of the bone marrow derived MSC from the fetus is higher than that from the adult, but the adherent ability of the MSCs from the adult is higher than that from the fetus. CONCLUSION: Fetal bone marrow derived MSCs should be enough to sustain a steady supply of low differentiated cells for proliferation, hence an abundant and accessible cellular reservoir for stem cell bioengineering, whereas adult bone marrow derived MSCs are more useful in hematopoietic reconstitution in bone marrow transplantation.
Assuntos
Células-Tronco Adultas/citologia , Células da Medula Óssea/citologia , Células-Tronco Fetais/citologia , Células-Tronco Mesenquimais/citologia , Adulto , Células-Tronco Adultas/imunologia , Células-Tronco Adultas/ultraestrutura , Células da Medula Óssea/imunologia , Células da Medula Óssea/ultraestrutura , Ciclo Celular , Diferenciação Celular , Linhagem da Célula , Proliferação de Células , Células Cultivadas , Células-Tronco Fetais/imunologia , Células-Tronco Fetais/ultraestrutura , Citometria de Fluxo , Humanos , Imunofenotipagem , Células-Tronco Mesenquimais/imunologia , Células-Tronco Mesenquimais/ultraestrutura , Microscopia EletrônicaRESUMO
There has been an increasing interest in recent years in the stromal cell system. The stroma is a complex tissue, composed of a number vascular and connective tissue cell types including endothelial cells, adipocytes, smooth muscle cells, osteogenic cells, and stromal cells. The marrow mesenchymal stem cells are capable of self-renewal and differentiate into various connective tissue lineages including bone, cartilage, tendon, muscle, fat, and marrow stroma. Recently, techniques for the isolation of adult bone marrow-derived human and animal mesenchymal stem cells have been described, as well as the methods to directing their differentiation into osteogenic, chondrogenic, tendogenic, myogenic, adipogenic, and marrow stromal lineages. But there is no report about the fetal bone marrow- and liver-derived mesenchymal stem cells. Are they the same or not? In our assay, human fetal mesenchymal stem cells from 4 - 5 months old human fetal bone marrow and liver low-density mononuclear cells were cultured, and the cell cycle, immunophenotype and ex vivo expansion properties were studied. Results showed that the mesenchymal stem cells from fetal liver and fetal bone marrow were similar in morphology, growth character and immuno-phenotypes, but the liver mesenchymal cells manifested higher ability to support hematopoiesis than the marrow-derived mesenchymal cells. This study demonstrates that adherent fetal marrow- and liver-derived cells cultured in the absence of differentiation stimulus gave rise to a population of cells with phenotypical features of mesenchymal stem cells, and should be enough to sustain a steady supply of low differentiated cells upon proliferation.
RESUMO
Mesenchymal stem cells (MSCs) have been cultured from many sources, including bone marrow and liver. To further support our hypothesis that MSCs exist in most postnatal tissues, we isolated a clonogenic, multipotent, rapidly proliferating population of cells from a fetal pancreas and termed them "pancreas-derived mesenchymal stem cells" (PMSCs). They withstood being passaged as many as 30 times without sustaining significant structural changes. In this study, we showed that PMSCs are positive for CD44, CD29, and CDI3 but negative for CD34 and HLA-DR and that they stained with collagen I and III but not with von Willebrand factor antibody. During the log phase of growth, PMSCs proliferated, doubling in population in about 30 hours. Cell-cycle analysis showed that more than 90% of cells were in the G0 and G1 phases, whereas a small subpopulation of cells were actively engaged in proliferation (S + G2 + M = 3.55%). Under differentiation culture conditions, PMSCs differentiated into cells of osteogenic, chondrogenic, and adipogenic lineages. These results demonstrate that PMSCs can be isolated from human fetal pancreas by means of their adherent ability and that they are capable of self-renewal, propagation, and multipotent differentiation.
Assuntos
Feto/citologia , Mesoderma/citologia , Pâncreas/embriologia , Células-Tronco/citologia , Sequência de Bases , Ciclo Celular , Diferenciação Celular , Divisão Celular , Primers do DNA , Humanos , Imuno-Histoquímica , Fenótipo , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
OBJECTIVES: To explore the feasibility of DC being in vitro induced from AML cells with cytokine cocktails and their biological properties. METHODS: AML cells were cultured in either presence or absence of cytokine cocktails. DC were studied for morphology, and cytochemical and immunofluorescent staining. Functions of DC were examined by MLC, FITC-conjugated dextran uptake test, and LDH release assay. RT-PCR and FISH were used to analyze the specific fusion genes of culture-derived DC. RESULTS: Classical DC morphological changes occurred in all 15 cultured AML cells. DC-associated surface molecules such as CD(1a), CD(80), CD(86), CD(106), CD(83) and HLA-DR were upregulated (P < 0.05). The allostimulatory abilities of culture-derived DC were significantly higher than those of AML cells uncultured or cultured in the absence of cytokines (P < 0.05). Culture-derived DC only in the presence of GM-CSF + IL-4 have phagocytotic activities. CTL assay was performed in 5 of the 15 samples. At effector/target ratio of 20:1, auto-T lymphocytes primed with the culture-derived DC exhibited no more killing activity to auto-AML cells than those stimulated by IL-2 or uncultured AML cells. Culture-derived DC presenced the native AML-specific aberrant karyotype and related fusion gene. CONCLUSIONS: Cytokine cocktails could in vitro induce AML cells into DC with classical morphology, immunophenotype and function. DC maturity induced by different cytokine cocktails could be variable. Culture-derived DC were originated from the native AML cells. AML cells could make the auto-T lymphocyte anergy.
Assuntos
Diferenciação Celular/efeitos dos fármacos , Citocinas/farmacologia , Células Dendríticas/citologia , Leucemia Mieloide Aguda/imunologia , Monócitos/efeitos dos fármacos , Adolescente , Adulto , Idoso , Sinergismo Farmacológico , Feminino , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Humanos , Técnicas In Vitro , Interleucina-4/farmacologia , Leucemia Mieloide Aguda/patologia , Masculino , Pessoa de Meia-Idade , Monócitos/citologia , Fator de Necrose Tumoral alfa/farmacologiaRESUMO
The effects of the Smad3- knockout on the hematopoiesis of mouse were investigated in this work. Five pairs of wild type and Smad3- null mice were studied. White blood cell(WBC), red blood cell(RBC) and platelet (PLT) counting of peripheral blood cells were performed with blood obtained from tails. And white blood cells were classified by their morphology. Bone marrow nucleated cells (BMNCs) were counted and classified. The CFU-GM, BFU-E, CFU-GEMM yields were measured in each pair of mice. CFU-S yield of each mouse was measured by injecting bone marrow cells into lethally irradiated 8-10 weeks old wild type female mice. And the pathomorphism of their bone marrows, spleens and livers were observed. As a result, WBC and PLT of Smad3- null mice were significantly higher than those in wild type mice. Smad3- null mice had much more proportion of granulocytes in classification. There wasn't any difference in RBC counting and BFU-E measurement. The yield of CFU-GM increased, while the yields of CFU-GEMM and CFU-S markedly reduced. Bone marrows are actively proliferative, with granulocytosis. The granulocyte/erythrocyte ratio increased. There were no obviously alterative in spleen and liver. Thus Smad3- knockout results in a decreased number of stem and progenitor cells. Moreover hematopoietic differentiation is abnormal with a tendency to forming more granulocytes and platelets. The effect of Smad3 on hematopoiesis is correlative to that of TGF-beta.