Articular cartilage repair is limited. Current treatments for cartilage defect are less satisfactory, and rarely restore full function or return the tissue to its native normal state. The rise of tissue engineering holds great promise for the generation of functional cartilage tissue substitutes. The history of cartilage tissue engineering and highlights the applications and advantages of various kinds of scaffolds in cartilage tissue engineering, such as native scaffolds, synthesis scaffolds, composite scaffolds and nanometer scaffolds had been introduced. But native scaffolds have weak strength and immunogenicity insufficiency, synthesis scaffolds degrade quickly, whose degrading products have cytotoxicity,which need further improvement. The application of superficial decoration overcomes the disadvantage of some scaffolds to an extend. Composite scaffolds possess the advantages of several scaffolds, it points out the direction of future scaffolds research. The development of Nanometer technique endows newly-synthesis scaffolds with nano-grade, thus it has some advantages and give a new way for the development of tissue engineering. At the end, the problems of these scaffolds, their trend of development and perspective studies were discussed.

2% hydroxypropyl methyl cellulose (HPMC, medical grade, Taian Ruitai Cellulose Co., Ltd.) was added into calcium phosphate cement (Orthopedics Institute of General Hospital of Chinese PLA) and the mixture was put into distilled water to observe whether the surface was corrupt. Some calcium phosphate cement was immersed in water at different time and the residual cement was weighed 24 hours later. The results showed that there was no surface corruption in calcium phosphate cement with 2% HPMC after shake; the residual weight measured 24 hours later showed that 2% HPMC could shorten calcium phosphate cement cohesion time from 4 minutes to 1 minutes. The experiment indicates that 2% HPMC can significantly increase the waterproof performance of calcium phosphate cement, increase the work time and is adaptable in clinical application.

Objectives: To evaluate the feasibility, safety and validity of the early enteral nutrition in severe acute pancreatitis(SAP). Methods: 15 patients of SAP during April 2002 and June 2003 had received early enteral nutrition through naso jejunal tube. The nutrition and immune index and the rates of complications were analyzed. Results: 2～3 days after nutrition tube placed to stomach, the tube heads in 11 cases reached the jejunum automatically, while 3 cases needed the help of X ray and 1 case needed the help of gastroscopy. All of 15 cases tolerated the enteral nutrition well, and there was no relapse of SAP. The nutrition and immune measurement were improved after 2 weeks' enteral nutrition, without infection of pancreatic necrosis. Conclusions: It is safe, efficient and feasible of the early enteral nutrition in severe acute pancreatitis(SAP) through naso jejunal tube. Early enteral nutrition can improve the nutrition, immune function and prognosis.

Objective: To explore the cause and the strategy for air quantity signaling in old patients using mechanic air. Method: Summary and analysis of the causes for air quantity signaling in 187 cases of old patients using respiratory machine. Results: One hundred fifty-one cases showed low-limited air quantity signaling per minute whereas 36 cases presented high-limited air quantity signaling per minute. Conclusion: Judging and removing the obstacle in respiratory machine on time and accurately are the key point raising both the survival rate of severe patients and the successful rate of mechanic air.

Objective To identify the determinants of average length of stay of 16 upper first-class general hospitals from 2000 to 2007.Methods Relative data of 16 upper first-class general hospitals from 2000 to 2007 were collected, and descriptive analysis and multiple linear regression analysis were employed to explore the determinants of average length of stay. Results Operation ratio and days before operation of inpatients, ratio of salary to medical income, ratio of doctors to nurses, successful rescue rate in emergency, number of operation tables and staff had impact on average length of stay. Conclusion Resource allocation should be optimized, health care quality be enhanced, reasonable salary scheme be designed, and rational medical insurance policies be implemented in hospitals to shorten average length of stay.

Objective To comprehensively evaluate the competitiveness of hospitals so as to provide objective referrences for the long-term development. Methods Competitiveness evaluation index system and evaluation model were established. Using related data of 2007, 16 hospitals nationwide were evaluated and factor scores and comprehensive scores were obtained by means of factor analysis. Results Four factors were extracted, which were "technical efficiency factor", "economic income factor", "sustainable development factor" and "resource allocation factor". All hospitals were ranked by each factor score and comprehensive score. Conclusion Each hospital has its advantages and disadvantages, therefore, hospital managers should constitute individual development strategy accordingly.

BACKGROUND:Epidemiologic reports have indicated that excessive weight-bearing exercise is one of important risk factors for lumbar degeneration, but the effects of weight-bearing activity on normal lumbar motion pattern are stil not clear. OBJECTIVE:To measure the changing characteristics and rules of position at the center of rotation of the lower lumbar spine during a weight-lifting activity of normal person. METHODS: Fourteen asymptomatic subjects with a mean age of (25±5) years were recruited for this study. The L4-5 and L5-S1 segments of each subject were CT-scanned to construct 3D models using dual X-ray imaging system and spiral CT examination combined technology in the aid of computer software. The physiological load and lumbar spinal 3D motion under the loading condition were reproduced when matching the flexion, neutrality and extension in the dual X-ray imaging system and on dual oblique lumbar X-ray image. Coordinate systems were established at the vertebral body of L4-S1 to obtain the center of rotation during flexion-to-neutral, neutral-to-extension and the ful flexion-extension motion. RESULTS AND CONCLUSION: (1) Under physiological load, the center of rotation of L4-5 of normal person was located about 1.0 mm anterior to the central axis of the vertebral body, and the center of rotation of L5-S1 was located about 0.7 mm anterior to the central axis of the vertebral body. (2) With weight loading, the center of rotation of both two segments shifted backward about 0.5 mm. There was no statistical difference between these two loading conditions. (3) When the center of rotation in flexion and extension was calculated respectively, the moving range of the center of rotation at both L4-5and L5-S1 became larger due to taking loads of 10 kg (P < 0.05). In flexion, the center of rotation at L5-S1 significantly shifted forward during a weight-lifting activity (P < 0.05). (4) These results confirm that compared with non-weight-bearing condition, the trajectory of the center of rotation was found to be increased when taking loads, especialy during the flexion-to-neutral motion.

Objective To synthesize a quantum dot (QD) to recognize glioma cells for imaging and photodynamic therapy. Methods By one-pot aqueous approach, near infrared-emitting CdTe was produced. After detection of its physicochemical characterizations, RGD was conjugated. Emission images were observed with confocal microscopy. To test its toxicity, CdTe-RGD with various concentrations was separately added into U251 and 3T3 cells for incubation in dark circulation. To test its photodynamic effect, U251 and 3T3 cells were then irradiated for 5 ~ 60 min using 632.8 nm laser. Results The QD (Φ = 3.75 nm, PL peak wavelength =700 nm, PLQY=20%) achieved was a spherical crystal with excellent monodispersity. Under confocal microscope , U251 cells were visualized but 3T3 cells not. In dark circulation, the survival rates of both U251 and 3T3 cells were above 85%. After laser irradiation, the survival rate of U251 cells decreased to (37 ± 1.6)%with the increasing of irradiation time and CdTe-RGD concentration. Conclusion With good physicochemical characterization and low toxicity, CdTe-RGD could be applied in biomedical imaging and photodynamic therapy of gliomas.

BACKGROUND: Clinical observation demonstrates that accelerated fracture healing or lower limb heterotopic ossifications always occur in patients with paraplegia. It indicates that peripheral nervous system may play an important role in fracture healing process.OBJECTIVE: To observe bone histomorphometery parameter, callus formation and biochemical change during the process of fracture healing of unilateral lower limb denervated tibia.DESIGN: Self-control animal experiment.SETTING: Tianjin Hospital.MATERIALS: Totally 36 six-month-old healthy male Wistar rats, with mean body mass of 210 g, were used in this experiment.METHODS: This experiment was carried out at Animal Experimental Center of Tianjin Hospital from March 2001 to March 2004. Denervated tibia fracture model and innervated tibia fracture model were made in the same rat. Animals were executed under anaesthetic status at week 2 and week 4 after fracture. Bilateral tibias were chosen to take radiografts.Biomachamical strength was measured and non-decalcification sections were prepared to perform bone histomorphometery observation.MAIN OUTCOME MEASURES: ① Comparison of wet weight of bilateral tibias and callus of rats between two groups after fracture. ②X-ray plain film scoring. ③ Biomechanical testing of tibial samples. ④ Histomorphological observation of fracture healing RESULTS: ① Wet weight of bilateral tibia and callus of rats in denervated group was much higher than that in innervated group at weeks 2 and 4 after fracture [(0.94±0.15) vs (0.76±0.14) g, (1.06±0.26)vs (0.81±0.10) g,P ＜ 0.05]. ②In X-ray plain film scoring, callus formation was significantly increased in denervated group (P ＜ 0.01). ③In biomechanical testing of three-point bending of tibial sample, callus intensity was significantly lower at weeks 2 and 4 after fracture in denervated group than in innervated group[ (9.88±8.49)vs ( 16.62±13.38 ) N, ( 12.77±7.55 )vs (20.19±10.60) N,P ＜ 0.05]. ④Bone histomorphometery showed that compared with innervated group, mineralized bone trabecula width of denervated group was significantly reduced (P ＜ 0.05), osteoid width was increased , osteoclast index and bone absorption area were significantly increased (P ＜ 0.05), and there were no significant difference of fibroblast index and bone formation area between two groups; Compared with innervated group, mineralized deposition rate in the denervated group was significantly reduced (P ＜ 0.05), the mature time of osteoid was elongated (P ＜ 0.05).CONCLUSION: Peripheral nervous system may play an important role during early and middle period of fracture healing. Intact innervation is essential for normal fracture healing.

Objective To accurately understand multi-spot medical practice in China and evaluate its effect.Methods Operation data of 2008 and 2009 were gathered from all medical institutions in Kunming to analyze the effect of the practice trial using the fixed effect model.Results Under control of such factors as the scale and type of the hospitals,clinic visits of the second certified hospital benefited by the practice increased by 14％than before,whereas the medical revenue of the institution increased by 29％.The effect proves more significant in terms of total clinic visits and medical revenues at level-1 and level-2 medical institutions.Conclusion Multi-spot medical practice in Kunming proves successful as it increased medical service supply and medical revenue,especially for level-1 and level-2 medical institutions.This effect possibly results from releasing high-level physicians down to lower-level institutions,helping these institutions to attract patients.