OBJECTIVE: To summarize the biocharacteristics, separation and purification as well as the culture technique of bone marrow mesenchymal stem cell, which has the potentiality of multiple cellular differentiations, locatedinduced differentiation of bone and cartilage, cellular carrying tray and application in bone tissue engineering.DATA SOURCES: Relative articles were retrieved through Medline database according to the key words of "mesenchymal stem cell, tissue engineer" in English between January 1990 and December 2004. Meanwhile,relative articles were also retrieved in Chinese journal full-text database and Wanfang database with the same key words in Chinese between January 1994 and December 2004.STUDY SELECTION: Articles were retrieved first to select those references which were related to the aspects of biology, isolation and culture of mesenchymal stem cell in tissue engineering. Representative and lated references were included; however, researches on non-bone tissue engineering and repetitive studies were excluded. The rest of articles were looked up for their full text.DATA EXTRACTION: There were 78 articles on mesenchymal stem cell in tissue engineering. Among them, 31 papers were included; the otherbut 47 papers including 13 articles of similar contents and 34 studies on nonbone tissue engineering were excluded.DATA SYNTHESIS: Mesenchymal stem cell mainly existed in bone marrow and could differentiated into multiple tissue cells and increase in vitro.① There were three methods for separation, purification and culture of mesenchymal stem cells: density gradient centrifugation, flow cytometry and adherent screening method. Other scholars obtained cell strain of mesenchymal stem cell through single-cell cloning technique, but this way was more difficult to obtain multiple seed cells. At present, density gradient centrifugation was widely used. ② Mesenchymal stem cell could differentiate into bone cells and cartilae cells through adding inductor into eligible culture medium. Ideal scaffolds could carry and retain the vitality of cells, support rapid endogeny of vessels and be benefit for observing new bone formation under X ray. New bone might be absorbed and replaced in bone rebuilding and form or increase conductive bridging of host bone. Functions of differentiated cells could be maintained by the interaction between scaffolds surface and cells, and the histocompatibility was well. ③ Mesenchymal stem cell was an kind of ideal target cells for gene therapy. It could shift growth factor or cytokine and express foreign protein after multiple desintegration in vitro. It was successful in bone tissue engineering.CONCLUSION: Modern tissue engineering which is presented by stem cells develops quickly at present, but tissue engineering of mesenchymal stem cell starts just now. Bone marrow mesenchymal stem cell is characterized by easily materializing, potentiality of multiple tissue differentiation, stable genetic background, non-rejection in implant button and high proliferation. All properties determine that it will be a useful thing in cell and gene therapy as well as tissue engineering.

BACKGROUND:Studies have found that combination of two of chitosan (CS), nano-hydroxyapatite (nHA) and poly(lactide-co-glycolide) (PLGA) can improve the mechanical properties and biocompatibility of the composite stent in certain extent as wel as improve osteogenic differentiation of the cels, but there is a certain distance from the ideal bone tissue engineering scaffolds.
OBJECTIVE:To study biocompatibility and osteoinductive activity of nHA/CS/PLGA scaffolds with different proportions in vitro.
METHODS: nHA/CS/PLGA scaffolds were prepared at mass ratio of 10:10:80, 10:20:70, 20:10:70 respectively by particle leaching method. And human bone marrow stem cels (hBMSCs) were co-cultured with these scaffolds in vitro. Adhesion, proliferation, and osteoinductive activity of these scaffolds were examined qualitatively and quantitatively by growth curve of hBMSCs on scaffolds. Gene expression of alkaline phosphatase activity and osteocalcin was detected by RT-PCR.
RESULTS AND CONCLUSION: hBMSCs could be attached, proliferated, and osteoinduced better on the nHA/CS/PLGA scaffold with the mass ratio of 20:10:70, compared to the other two groups of scaffolds. The differences were significant statisticaly (P< 0.05). Alkaline phosphatase and osteocalcin expressions were respectively higher in the scaffold with the mass ratio of 20:10:70 after 9-27 days of co-culture and 15-27 days of co-culture, in comparison with the other two groups of scaffolds. These findings indicate that the nHA/CS/PLGA scaffolds with the mass ratio of 20:10:70 demonstrated preferable biocompatibility and osteogenic inductivity, which is expected to be a promising scaffold material for bone tissue engineering.

Objective To establish the method of isolation,culture and identify biological characterization of mesenchymal stem cells from human umbilical cord (hUCMSCs);and study their multiple differentiation potency.Methods Stem cells from human umbilical cord were cultured by enzyme Wharton jelly method in vitro.The surface markers were identified by flow cytometry.Multi-differentiation capacity was identified by osteogenic and adipogenic differentiation.ALP was detected with Calcium cobalt staining.The mineralized ability in vitro was measured with Alizarin red staining.Theadipocyte differen-tiation ability was measured with oil red-O staining.Results Flow cytometry analysis revealed that CD73 (92.45%),CD90 (95.45%)and CD105 (96.45%)were highly expressed on these cells’surface,while CD34 (1.07%)were negative ex-pressed.Cells were cultured with induced-osteogenic medium after 3 weeks,ALP staining in the cytoplasm of black parti-cles,and a large amount of mineralized nodules within cells was observed after 4 weeks.Cells were cultured with induced-adi-pogenic medium after 2 weeks,the majority of these cells were round,oil red O staining of lipid droplets generated within cells was observed.Conclusion Mesenchymal stem cells from human umbilical cord have the potential of multi-directional differentiation.These cells could be induced to differentiate into adipocytes and osteoblasts,which laid the foundation for clinical stem cell therapy research source of seed cells.

BACKGROUND: Acetabular malignant tumor reconstruction is to obtain pelvic stability and lower limb walking function to excise the tumor at safe margin.Excision range has been evaluated by MRI,CT,X-ray,which are subjective and lack preoperative design.Computer-aided three-dimensional reconstruction can evaluate tumor erosion range from all planes to accurately excise the tumor.OBJECTIVE: To evaluate the value of computer aided design in the treatment of acetabular malignant tumor.METHODS: One case with acetabular hemangiosarcoma was checked with lamellar CT scanning,which acquired some two-dimensional data in disease area.The three-dimensional reconstruction of anatomical model,design of cutting bone extent,design of individual prosthesis and sham operation were made by computer.Based on computer aided design proposal,acetabular tumor was resected,pelvic ring and right hip articulation were reconstructed with allogeneic semi-pelvis and individual total hip replacement.RESULTS AND CONCLUSION: The patient began to non-weight bearing walk with double crutches 2 months after operation.At6 months,the patient walked normally.The right hip joint motion was good with no pain.Postoperative X-ray film displayed individual prosthesis matched to pelvis.The patient fell a little numbness of skin in the lateral of right hip.No phlebothrombosis,prosthesis loosening or dislocation was found.Computer aided design has a good perspective of application in the treatment of acetabular malignant tumor.Individualized treatment can improve operation accuracy,reliability,convenience and curative effect.

Objective To determine the relationship among structural empowerment, occupational benefit and job embeddedness of nurses, and to analysis the role of occupational benefit in structural empowerment and job embeddedness. Methods A total of 422 nurses recruited from five tertiary hospitals in Tianjin. They were investigated with General Information Questionnaire, Condition of the Work Effectiveness Condition Questionnaire, Nurses' Occupational Benefit Scale and the Work Embedded Scale. Results The mean scores of nurses' work efficiency condition questionnaire, occupational benefit, and job embeddedness were (3.14 ± 0.88), (4.27 ± 0.53), (3.64 ± 0.677) points respectively. Structural empowerment, occupational benefit and job embeddedness were positively correlated (r=0.646, 0.536, 0.521, P<0.01);The nurses structural empowerment had significant prediction effect on work engagement (β=0.646, P<0.01),occupational benefit was a partial intermediary between structural empowerment and job embedding. Conclusion Through reasonable authorization, nursing managers actively guide nurses' sense of benefit, improve the close integration of nurses and organizations, then improve the level of nurses' work embedding.

Objective:To develop a questionnaire of knowledge, attitude and practice for intensive care unit nursing staff on prevention of enteral nutrition complications and test its reliability and validity.Methods:Based on knowledge-attitude-practice theory, the questionnaire was developed by using literature review, group discussion and Delphi expert inquiry.A convenience sampling method was used to select 204 ICU nurses from five hospitals in Tianjin from November to December 2021 for the survey to determine the reliability and validity of the questionnaire.Results:The finalized questionnaire included 3 dimensions and 40 items, explaining 68.499% of the variance. Cronbach alpha coefficients of total questionnaire and each dimension were 0.965, 0.946, 0.914 and 0.908 respectively. The content validity of the questionnaire was 0.929, while it ranged from 0.818 to 1.000 for each item.Conclusions:The questionnaire of knowledge, attitude and practice for intensive care unit nursing staff on prevention of enteral nutrition complications has good reliability and validity, and is suitable for measuring the current knowledge and nursing practice activities of ICU nurses on the prevention of enteral nutrition complications.