BACKGROUND:Tissue engineering scaffolds can create proper nerve regeneration microenvironment, enrich nutritional factors for nerve regeneration and promote axonal growth. OBJECTIVE:To review the progress of tissue engineering scaffolds in nerve repair in recent years. METHODS:A computer-based retrieval was performed to search ful-text articles addressing tissue engineering scaffolds used to repair nerve damage published from 2009 to 2014 in PubMed databases using the keywords of “nerve regeneration, prostheses and implants” as wel as articles published from 2004 to 2014 in CNKI database using the keywords of “nerve repair, material” in Chinese. RESULTS AND CONCLUSION: Currently, scaffold materials for nerve damage mainly include natural materials, naturaly derived materials, synthetic materials and composites, al of which have their own advantages and disadvantages. By chemical crosslinkers or chemical modification, the naturaly derived polymer can be combined with other natural or synthetic composite materials, to improve their physicochemical and biological properties, i.e., the composite scaffolds have better effects than single materials in nerve regeneration. Therefore the current research focus is composite materials. In clinical research, colagen scaffold for nerve repair has entered the clinical research stage.

Objective To develop an efficient recombinant expression system of alanine aminotransferase ( ALT ) in order to build the foundation for the preparation of feedstock related ALT reference materials.Methods A new human ALT gene was synthesized by optimizing the codons of the nucleic acid sequence encoding human ALT using bioinformatic tools, and then it was cloned into pRSF-Duet expression vector.The recombinant plasmid pRSF-Duet-ALT was transformed into E.coli BL21 and the target protein expression was induced by 2 mmol/L isopropyl β-D-1-thiogalactopyranoside ( IPTG ) .The expression condition for soluble protein was optimized by changing the inducer concentration, shaking speed and induction temperature. The soluble protein was purified by nickel ion affinity chromatography and dextran molecular sieve chromatography, and identified by sodium dodecyl sulfate-polyacrylamide gelelectrophoresis( SDS-PAGE) and Western blot analysis.The activity and stability of recombinant proteins in serum matrix under different storage conditions were detected.Results The usage frequency in E.coli of ALT codons was more than 10%after codon optimization.The expressions of soluble proteins were increased by optimizing the induced expression conditions, including a final concentration of 2 mmol/L of IPTG, and continued incubation with shaking at 150 rpm for 8 h at 25℃.The purified protein was identified as ALT by SDS-PAGE and Western blot with ALT activities of up to 80 000 U/L.Recombinant ALT could be stable for 2-8 d at 2-8 ℃or 25 ℃with a relative standard deviation of less than 5%.Conclusions An efficient recombinant expression system of ALT was developed successfully by codons optimization.The obtained recombinant protein could achieve the requirements of reference material feedstock.

BACKGROUND:In the present quality control file or technique standards of in vitro fertilization medium, the indicators of the component contents and detection methods have not been clearly defined. To ensure the safety and effectiveness of these products, we should establish the quality standards as early as possible. OBJECTIVE:To establish a method for determining the three main bioactive constituents of in vitro fertilizationmedium including glucose, lactic acid sodium salt, pyruvic acid sodium salt by ultra-high performance liquid chromatography tandem mass spectrometric method (UHPLC-MSMS), and to analyze the content of each constituent. METHODS:The UHPLC-MSMS was used, and UHPLC separation was performed on a SUPELCO Discovery HS F5-3 column (15 cm × 2.1 mm, 3μm) in a gradient elute mode with acetonitrile and water (both containing 0.1%formic acid) as the mobile phase at a flow rate of 0.35 mL/min. The column temperature was 40℃. Mass spectrometry detection was performed with multi-reaction monitoring mode using negative electro spray ionization. RESULTS AND CONCLUSION:The linearity was achieved in the range of 0.1-10μg/mL (r=0.999 8) for glucose, 0.05-5μg/mL (r=0.999 4) for lactic acid sodium salt, and 0.1-10μg/mL (r=0.999 4) for pyruvic acid sodium salt. The recoveries were 96.4%-98.1%with relative standard deviation less than 2.8%. To conclude, the UHPLC-MSMS method is sensitive, rapid, accurate and specific, thus providing a basis for the quality standard study of in vitro fertilization medium.

Objective To develop a new system of computer-aided design(CAD) for individual metacarpophalangeal joint prosthesis based on rapid prototyping technique. Methods A hand of cadaver was scanned with PLUS-4 spiral computed tomography (CT).Then the transaxial 2D image data of digitus metacarpophalangeal joint were reconstructed into 3D digitized contour data by 3DMSR that was designed by ourselves. Then,the intramedullary stem was designed in software of Surface 9.0. Results The 3D contour image of metacarpophalangeal joint presented was reconstructed by 3DMSR and edited by Surface 9.0 easily for CAD of individual metacarpophalangeal joint.The intramedullary cavity was like choanoid. The intramedullary stem longitude of articular head and fossa were 47.31 and 35.20 mm.The intramedullary stem fit cavity.The model fit anatomical shape. Conclusion The 3D contour image of metacarpophalangeal joint can be obtained by spiral CT scanning,and the digitized data can be applied directly to CAD of individual artificial joint and subsequently rapid prototyping fabricating.In addition,the reconstruction method is simple and can be applied widely to clinical implant fabricating practice of orthopaedics.

Objective To investigate the effects and the mechanism of sorafenib on hepatocellular car-cinoma growth and vasculogenic mimicry (VM)in mice.Methods A subcutaneous implantation mouse model of human hepatocellular carcinoma (HCC)HepG2 cells were established.Mice inoculated with HepG2 cells were randomly divided into the treatment group (sorafenib 30 mg·kg -1 ·d -1 )and the control group by using of paired comparison method.Growth of established tumor xenografts was monitored at least twice weekly by vernier caliper measurements.VMwas assessed by immunohistochemical assay and periodic acid schiff reaction (PAS)histochemical double-staining.The expressions of HIF-1 α,VEGFA,VEGFR-1 and MMP-2 in tumor tissues were also assessed by immunohistochemical assay,Western blotting and real-time quantitative PCR. Results The tumor volume in the sorafenib group was obviously decreased compared with the control group (809.69 mm3 ±208.71 mm3 vs 1 678.00 mm3 ±31 3.29 mm3 ),with a statistically significant difference (t =6.1 03,P =0.030).Haematoxylin and eosin (HE)staining showed that tumor tissues treated with sorafenib were characterized by obvious necrosis,but there were not the same cases in the control group.Sorafenib group significantly reduced the number of tumor functional vessel in HepG2 xenografts compared with the control group,as assessed by tumor vasculature uptake of DiOC7 (4.77 ±0.1 5 vs 8.44 ±0.68,t =9.1 92,P =0.01 3).The number of VMwas significantly decreased by sorafenib (1 .04 ±0.46 vs 2.66 ±0.42,t =4.51 0, P =0.041 ).Relative to controls,CD31 -positive vessels decreased after treatments (3.42 ±0.1 0 vs 1 .26 ± 0.1 4),with a statistically significant difference (t =21 .580,P =0.002).Compared with the control group, the protein levels of HIF-1 α(0.65 ±0.03 vs 1 .00 ±0.00),VEGFA (0.51 ±0.02 vs 1 .00 ±0.00), VEGFR-1 (0.45 ±0.04 vs 1 .00 ±0.00)and MMP-2 (0.69 ±0.02 vs 1 .00 ±0.00)were significantly decreased in the sorafenib group (t =1 9.650,P =0.003;t =40.493,P =0.000;t =23.429,P =0.002;t =26.071 ,P =0.002).Compared with the control group,the mRNA levels of HIF-1 α(0.78 ±0.05 vs 1 .00 ±0.00),VEGFA (0.52 ±0.05 vs 1 .00 ±0.00),VEGFR-1 (0.45 ±0.02 vs 1 .00 ±0.00)and MMP-2 (0.71 ±0.02 vs 1 .00 ±0.00)were also significantly decreased in sorafenib group (t =6.840,P =0.021 ;t =27.71 0,P =0.001 ;t =62.740,P =0.000;t =23.850,P =0.002).Conclusion Sorafenib can inhibit the tumor growth and VMchannels formation,which may be related with the HIF-1 αand VEGFA /VEGFR-1 signa-ling pathway.

Objective To study the relationship between IGF-1, IGFBP-3 and prostatic volume (PV) by examining the levels of insulin and insulin-like growth fator-1 (IGF-1) and insulin-like growth factor binding protein-3 ( IGFBP-3 ) and other indicators in patients with impaired glucose regulation and benign prostate hypertrophy. Methods According to 75 g oral glucose tolerance test (OGTT) results, 109 BPH patients aged over 50 years were divided into three groups: normal glucose tolerance (NGT) group (n = 56), impaired fasting glucose (IFG) group (n = 14), impaired glucose tolerance (IGT group, n = 39). The biochemical indicators and postatic hyperplasia related factors and IGF-1, GFBP-3 were measured. Results There were no statistical differences between the three groups in terms of blood lipids, homocysteine, urinary inhibition C, fasting insulin (FINS), glycosylated hemoglobin, IGF-1 and IGFBP-3 (P > 0.05). There were no significant differences between the groups in terms of PV, prostate specific antigen, the quality of life score and the international prostate symptom score (P > 0.05). Fasting plasma glucose and insulin resistance index (HOMA IR) were higher in IFG group than NGT group (P′ < 0.017) and IGT group (P′ < 0.017). 2-hour plasma glucose and 2-hour insulin were higher in IGT group than NGT group (P′ < 0.017) and IFG group (P′ < 0.017). PV was positively correlated with FINS but not correlated with IGF-1, IGFBP- 3 by multiple multiple step wise regression analysis. Conclusion Oyperinsulinemia is a risk factor in the development of BPH with IGR, and IGF-1 and IGFBP-3 are not associated with BPH risk. Further investigation is needed to elucidate the role of the IGF-1 and IGFBP-3 in BPH.

Objective:To investigate the regulatory mechanism of PESV on tumor-infiltrating natural killer ( NK) cells in a mice model with H22 orthotopic transplantation tumor .Methods:Suspensions of H22 cells were injected into the lobe of liver on C 57BL/6 mice for establishing liver orthotopic transplantation tumor model ,then the mice were randomly divided into four groups:normal group , control group ,PESV low dose group ( PESV-L ) and PESV high dose group ( PESV-H ) .Mice were either sacrificed for mechanistic studies or survival followed 14 days of therapy.The volume and weight of the tumor were measured .The proportion of infiltrating NK cells was measured by flow cytometry and the expression of NK 1.1(NK) cells was investigated by immunohistochemistry method .The expression of perforin and granzyme B were further investigated by real-time PCR.Results: In contrast to control group , the tumor inhibition rate was 15.38%and 30.77% in PESV-L group and PESV-H group respectively.The survival showed that PESV-H could significantly prolong the survival time of mice ,and life extension rate was 34.06%,(P<0.05).Histological analysis revealed significant pleomorphism of the neoplastic cells and invasive extendion in control group ,while there were more necrosis and less degree of atypia in PESV-L and PESV-H.The level of tumor-infiltrating NK cell was significantly higher in PESV-H than in tumor-bearing control group [(5.91±0.49)%vs.(3.69±0.50)%,P<0.05],and NK cells were infiltrating in peritumoral lesions.The mRNA of perforin and granzyme B in PESV-H were respectively 3.62 and 5.82 times than that of control group ( P<0.05 ) .Conclusion: These findings suggest that the treatment of PESV might increase the infiltration of natural killer cells in the orthotopic transplantation tumor and contribute to NK cells migration to the tumor , which induct and maintain the activities of natural killer cells against tumor cells by expressing perforin and granzyme B in vivo .

BACKGROUND:The blastula culture medium can assist the development of zygote from the fertilized egg to the blast blastula. The safety and quality of blastula culture medium directly influences the quality of blastula. OBJECTIVE:To evaluate the effect of blastula culture medium on the development of mouse embryos. METHODS: In this study, B6D2F1 mice were used. The female mice were superovulated and mated with male B6D2F1 mice. One day later, the zygotes were colected and cultured in the M16 medium to 4-cel stage. Then, 4-cel stage embryos were transferred into the tested blastula culture medium (experimental group). After 5 days of culture, the forming rate of blastula was examined. Meanwhile, the M16 medium containing endotoxin was used to culture 1-cel mouse zygote (positive control group). The M16 medium with no embryo toxicity was used to culture 1-cel zygote (negative control group). RESULTS AND CONCLUSION:The formation rate of blastula was 0 in the positive group, 87.1% in the negative control group, and 87.3% in the experimental group. From the results, the tested blastula culture medium could assist the 1-cel zygote growing to the stage of blastula, and the formation rate of blastula was above 80%. The tested blastula culture medium had no toxicity to the mouse embryo.

Objective To investigate the time-effect relationship of angiogenesis induced by ultrasound.mediated microbubble destruction in the skeletal muscle of rats.Methods Forty-eight healthy SD rats were divided into 4 groups:ultrasound-mediated microbubble destruction group,ultrasound only group,microbubble only group and control group.In ultrasound-mediated mierobubble destruction group, microbubbles were inj ected by vein at a dose of 0.5 ml and the target skeletal muscle was radiated at 2.0W/cm2.In ultrasound only group,the target skeletal muscle was radiated at 2.0 W/cm2.In microbubble only group.microbubbles were injected by vein at a dose of 0.5 ml.The control rats were without ultrasound radiation and microbubbles.On the 3rd,7th,10th,14th,21st and 28th day after the ultrasound radiation,two rats in each group were sacrificed and the target skeletal muscle was harvested for HE staining to observe the microstructure of tissue,immunohistochemistry staining was used to count the microvessel density (MVD),enzyme 1inked inmmunosorbent assay(ELISA)was used to detect the expression of vascular endothelial grouth factor(VEGF).Results Angiogenesis was significant in ultrasound-mediated mierobubhle destruction group,but a little in ultrasound only group.There was not any angiogenesis in either microbubble only group or control group.MVD and VEGF expression of ultrasound-mediated microbubble destruction group arrived at a peak on the 1Oth day as well as on the 14th day of ultrasound group.Conclusions Ultrasound-mediated microbubble destruction can facilliate the endogenous secretion of VEGF quickly and more,and accelerate the angiogenesis in the skeletal muscle.

Objective To observe the extent of bone coagulation and the thermal field distribution created in ablating the swine vertebral bodies in vitro with multi-polar radiofrequency and to discuss the correlation between the electrode position in the vertebral body and the safety of the spinal cord as well as the soft tissue injury around the vertebral body. Methods Thirty fresh adult porcine vertebrae, were randomly and equally divided into two groups. The depth of the electrode needle was 10 mm or 20 mm. When the ablation process reached to a stable state, the temperature at the scheduled spots was estimated. Twenty minutes after ablation, the vertebral body was cut along the electrode needle plane and also along the plane perpendicular to the electrode needle to observe the extent of bone coagulation. Results The temperature at the scheduled spots reached to a stable state in 3.5 minutes. The more close to the electrode the spot was,the more quickly the temperature rose. No soft tissue injury around the vertebral body was observed in both groups and no spinal cord injury occurred when the electrode needle was 10 mm or 20 mm deep in the vertebral body. Conclusion In treating vertebral metastases, the radiofrequency ablation is safe and reliable if the posterior wall of the vertebral body remains intact.