95%). Conclusion Immunomagnetic separation can effectively isolate and purify PSCs.

Objective　To manufacture adriamycin-porous tricalcium phosphate (A-PTCP) ceramic drug delivery system (DDS)as a possible method for bone defect treatment after bone tumor operation. Methods　A-PTCP DDS was made from putting adriamycin into PTCP. Thirty rabbits were divided randomly into group A(24 rabbits) and group B(6 rabbits). A-PTCP was implanted in the greater trochanter of the right femur in group A. Adriamycin were injected into veins in group B. Muscle around A-PTCP and plasma were taken out at different period. Adriamycin concentrations in muscle and plasma were measured by high performance liquid chromatography (HPLC). Results　A-PTCP could gradually release adriamycin over 10 weeks. Adriamycin concentrations in the muscle were higher than that in plasma. Conclusion　A-PTCP may be a new method for repairing bone defects after bone tumor operation.

To investigate the technique of sorting high-purity precartilaginous stem cells from rat's perichondrium, neonatal rat's perichondrium cells suspensions were incubated with monoclone antibody of anti-fibroblast growth factor receptor-3 (anti-FGFR-3), and the labeled cells were separated from the suspension in the magnetic field by immuno-beads coated with the second antibody. Purity of the sorted neural stem cells was found to be 93.0%-99.0%, with living cells amounting to 80% -85 %. The magnetic cell sorting system could effectively separate precartilaginous stem cells from perichondrium cell suspensions.

BACKGROUND: Myelination following axonal regeneration is a key factor affecting the recovery of spinal cord injury. Oligodendrocyte survival directly affects the myelination following axonal regeneration. OBJECTIVE: To investigate the feasibility of differentiation of rat bone marrow mesenchymal stem cells (BMSCs) into oligodendrocytes induced by neurotrophic factors. DESIGN, TIME AND SETTING: The cell molecular biology in vitro study was performed at the Laboratory of Department of Orthopaedics, Tongji Hospital from September 2006 to June 2007. MATERIALS: A total of 5 Sprague Dawley rats aged 2-4 weeks, of both gender were selected. Bilateral femur and tibia bone marrow was obtained to harvest BMSCs. METHODS: At passage 4, BMSCs were incubated in serum-free medium, supplemented with N2, 20 ng/mL basic fibroblast growth factor, 20 ng/mL epidermal growth factor for 48 hours, and incubated in medium containing 500 ng/mL insulin-like growth factor I and N2 for 3 days. MAIN OUTCOME MEASURES: Morphological changes were observed using an phase contrast microscope. Semiquantitative RT-PCR was utilized to detect specific marker mRNA expression of oligodendrocytes. Using neuron marker anti-microtubule-associated protein, astrocyte marker anti-glial fibrillary acidic protein, oligodendrocyte marker anti-galactocerebroside, anti-myelin basic protein antibody, immunocytochemical staining was performed to detect the positive rate of the differentiation of BMSCs into oligodendrocytes. RESULTS: Morphological changes in BMSCs during the differentiation into oligodendrocytes: After the induction, a majority of BMSCs presented the morphological characteristics of oligodendrocytes. Cytoplasm retraction towards nucleus, cell process extension towards outwards, and strong refraction were found. With the prolongation of time, several cell processes connected and formed a typical net-shape structure. Specific marker mRNA expression of oligodendrocytes: Following induction, specific strap of myelin basic protein mRNA and galactocerebroside mRNA could be detected. Positive rate of oligodendrocytes: During induction, the positive rates of galactocarebroside, myelin basic protein and microtubule-associated protein were 65%, 45% and 10%, respectively. CONCLUSION: The combination of epidermal growth factor, basic fibroblast growth factor and insulin-like growth factor can effectively promote the directional differentiation of BMSCs into oligodendrocytes.

Objective In order to eliminate the influences caused by temperature and electrode-polarization, a new circuit of measuring electrical conductivity of water is designed by AT89S52 single-chip. Methods The system adopts the bi-directional pulsed voltage as its exciting source and the DS18B20 sensor as temperature compensation circuit component. Results Three functions which include auto-control, signal-collecting and display are realized by using C51 high-level language to write the modularization program. The precision of system is improved by an auto-temperature compensation way to avoid the blindness of temperature coefficient. Conclusion The system has such advantages as high accuracy and simple operation. Through further fulfilling, it can accord with user applying.

Objective To study the effect of stable expression of reconstructed human transforming growth factor-β3 ( hTGF-β3) on proliferation of precartilaginous stem cells ( PSCs) and their differentiation into cartilage chondrocytes.Methods After isolated and purified by immunological microbeads,PSCs of rats were transfected with pcDNA3.1 ( + )-hTGF-β3.MTT reduction assay ( MTT) and flow cytometry were performed to investigate the effect of transduction on proliferation and DNA synthesis.Biosynthesis of hTGF-β3 and expressions of cartilage associated genes and proteins were examined by qRT-PCR,immunohistology and Western blot.Results hTGF-β3 was expressed in PSCs stably.Compared with non-transfection group,PSCs' DNA synthesis level and proliferation rate were significantly increased after transfection.Quantitative real-time PCR and immunological investigation suggested up-regulated expression of specific genes and proteins of chondrocyte and increase of deposition of chondrocyte typical extracellular matrices proteoglycan and collagen type Ⅱ .Conclusions Gene enhanced PSCs can stably express hTGF-β3 protein to promote proliferation of PSCs and induce differentiation of PSCs in to chondrocytes,which provides a fresh approach to cartilage tissue engineering.

Objective To study the biological effects of sinusoidal electromagnetic fields(EMFs)on proliferation and extracellular matrix(ECM)formation by annulus fibrosus(AF)cells in rats.Methods AF cells isolated from rats were randomly divided into a control group and an experimental group.The cells in the experimental group were stimulated with an EMF,while those in the control group were held under the same culture conditions but with no EMF.Flow cytometry and MTT were performed to observe the effects on the ceU cycle and proliferation.Collagen and aggrecan expression were examined after amplification with a reverse transcriptase polymerase chain reaction(RTPCR).Sulfated glycosaminoglycan(sGAG)content wag detected by applying the Alcian blue method. Results AF cell proliferation was not significant until after 4 days of stimulation.Compared with the control group,the expression of type Ⅰ and Ⅱ collagen and Aggrecan were up-regulated,and sGAG content Was increased in the experimental group.Conclusion AF cell proliferation was enhanced by EMF.Gene expression of collagen type Ⅰ and Ⅱ and Aggrecan increased.a8 well as sGAG levels.The results suggest an approach for treating of intervertebral disc degeneration.

Objective To study the operating parameters of the field seawater desalination reverse osmosis device by RO process and analyze quality of the product water.Methods In pressure of 4.90～6.37 MPa,the influence of operating pressure on salt rejection and water flux is researched to determine the best parameter.Except some conventional item test,the water quality analysis also includes BOD,COD,TOC,fluorescence spectra,ultraviolet spectra and chromatography of ions analysis.Results Operating pressure of 5.88 ～6.37 MPa,the water flux reaches 18 ～22 L/h and the ratio of desalinization exceeds 97.4%.The device has an organic contaminant elimination ratio higher than 95% and ion desalination ratio also more than 96%.The fundamental index is consistent with drinking water sanitary standard.Conclusion The field seawater desalination reverse osmosis device by RO process can effectively wipe off bacteria and contaminant of water and also can reduce salt salinity in untreated water to produce pure water for drinking.

This study examined the construction of eukaryotic expression plasmid of human transforming growth factor-β3 (hTGF-β3) and its inducing effect on the differentiation of precartilaginous stem cells (PSCs) into chondroblasts. hTGF-β3 gene was amplified by using polymerase chain reaction (PCR) and then inserted into the eukaryotic expression plasmid pcDNA3.1 to construct the eukaryotic expression plasmid pcDNA3.1(+)-hTGF-β3. Rat PSCs were isolated and purified by employing an immunomagnetic cell sorting system. pcDNA3.1(+)-hTGF-β3 was transfected into purified PSCs with the use of linear polyamines. The expression of TGF-β3 and cartilage-specific extracellular matrix (ECM) components was detected after transfection by real-time quantitative PCR, ELISA, immunochemistry and Western blotting, respectively. The results showed that the eukaryotic expression plasmid pcDNA3.1(+)-hTGF-β3 was successfully established as identified by enzyme digestion and DNA sequencing. Real-time quantitative PCR and ELISA revealed that hTGF-β3 was strongly expressed in pcDNA3.1(+)-hTGF-β3-transfected PSCs. Real-time quantitative PCR, immunochemistry and Western blotting showed that the cartilage-specific ECM markers, i.e., cartilage oligomeric matrix protein (COMP), Aggrecan, collagen type X and II were intensely expressed in the pcDNA3.1(+)-hTGF-β3-transfected cells. It was concluded that hTGF-β3 could be stably expressed in pcDNA3.1(+)-hTGF-β3-transfected PSCs and induce the differentiation of PSCs into chondroblasts.

Objective To investigate the possibility of transforming growth factor β (TGF-p) inducing chondrogenesis of precartilaginous stem cells (PSCs) and discuss expression mechanism of extracel-luar matrix. Methods PSCs were induced into a chondrogenic pathway in alginate bead culture in the absence of serum and in the presence of TGF-β1, β2, or-β3. The temporal pattern of expression of cartilage-specific extracellular matrix during chondrogenesis were analyzed by immunocytochemistry, immunoflu-orescence, RT-PCR, immunoprecipitation, Western blot and spectrophotometer. Results Type Ⅱ collagen staining was positive at days 7, 14 and 21 in alginate bead culture, showing most intense staining in the TGF-p3-treated culture. Expression of type Ⅱ collagen was increased in TGF-β3 group. Immunocytochemi-cal analysis of a number of other extracellular matrix components showed widespread expressions of aggre-can, fibromodulin and COMP in alginate bead culture that presented TGF-p3 for 21 days. The expressions of Aggrcan, fibromodulin, type Ⅰ and ⅹ collagen, and COMP were detected by RT-PCR in TGF-β3 group within 8 days, while type Ⅱ collagen began expression at days 8-21. COMP or type X collagen was present in TGF-β3 group at days 7, 14 and 21 by immunoprecipitation or Western blot analysis respectively. The extracted glycosaminoglycan content or the glycosaminoglycan/DNA rate in TGF-βl group was significantly lower than those in TGF-β2 group or TGF-β3 group at days 14 and 21 (P <0.01). Conclusions TGF-β can evocate chondrogenesis of PSCs, when rapid deposition of cartilage-specific extracellular matrix is involved. The sequential events in this pathway leading from the undifferentiated stem cells to mature chon-drocytes can be investigated by analysis of key matrix elements.