Objective To investigate the effects of collagen concentration and pre-freezing temperature on structure and properties of the scaffold. Method A series of porous collagen scaffolds were fabricated with different collagen concentration and pre-freezing temperature by freezing-drying. The effective pore sizes and other properties of the porous scaffolds were evaluated and compared with each other. Chondrocytes of rabbit were separated and cultured on these scaffolds to evaluate their biocompatibility. Result The collagen scaffolds had interconnected pore ranging from 50 to 200 ?m in pore size. With increasing the collagen concentration density and tensile strength of the scaffolds increased, while pore size and degradation rate of the scaffolds decreased, as well as become less homogeneous. Reducing pre-freezing temperature resulted in smaller poresize and slower degradation rate of scaffolds. MTT analyses demonstrated that all the scaffolds availed to cell attachment and proliferation, while increasing collagen concentration and decreasing pre-freezing temperature evidently restrained chondrocytes attachment and proliferation. Conclusion The collagen concentration and pre-freezing temperature have crucial influence on the structure and properties of collagen scaffolds. The suitable collagen scaffolds were obtained by adjusting the collagen concentration and pre-freezing temperature. The bigger of the pore size was. The faster cell proliferation was achieved.

Following the requirements for libraries in the Implementing Rules for Evaluation Standards of Tertiary Hospitals in Guangdong Province and taking municipal or above occupational disease prevention and control institutions as objects,the paper analyzes the construction situations,current collections and operating modes of libraries and discusses the setting of the occupational health information service function from 6 aspects of information sources,service objects and function setting,book retrieval,inter-library loan,service feedback and occupational health information service for labor.

BACKGROUND:Liposomes as a new drug delivery system are characterized by few adverse reactions, no immunogenicity and biodegradation. Furthermore, methotrexate-loaded liposomes can significantly reduce drug toxicity and improve anti-tumor effect. OBJECTIVE:To prepare long-circulating methotrexate-loaded liposomes and to evaluate its antitumor activity in MG-63 in vitro. METHODS:The methotrexate-loaded liposomes were prepared using the film dispersion method, and the long-circulating ones were prepared using the post-insertion method. The initial concentrations of methotrexate were 9.1, 1.82, 0.364 g/L. The ultracentrifugation method and spin column method with Sephadex G-10 or G-50 as packing were employed to separate free drugs from the methotrexate-loaded liposomes. Their recovery, size, morphology, encapsulation efficiency and drug-to-lipid ratio were evaluated. The cytotoxity of the long-circulating methotrexate-loaded liposomes purified with ultracentrifugation method and spin column G-50 method under three dose levels (0, 1, 5, 25 mg/L) were determined by MTS method. RESULTS AND CONCLUSION:According to the recovery rates of three methods, the spin column G-50 method was considered as optimal for the long-circulating methotrexate-loaded liposomes. The long-circulating liposomes were spherical or el ipsoidal under transmission electron microscope, about 200 nm in size. At the certain initial concentration of methotrexate, the encapsulation efficiency and drug-to-lipid ratio of the liposomes purified using the spin column G-50 method were remarkably higher than those purified using the other two methods. At the same mass concentration, the cytotoxity of the liposomes purified with ultracentrifugation or spin column G-50 was significantly higher than that of free methotrexate, and furthermore, the cytotoxity of the liposomes purified with spin column G-50 was higher than that of the liposomes purified with ultracentrifugation method. To conclude, the long-circulating methotrexate-loaded liposomes show a higher antitumor activity than free methotrexate in MG-63 cel s in vitro, providing the basis for further investigation of its antitumor effect on human osteosarcoma in vivo.

ObjectiveThe aim was to construct the recombinant plasmid of pET-28a-G-protein pathway suppressor 2 (GPS2) GPS2,express GPS2 protein in E.coli,and obtain specific polyclonal antiserum of GPS2.MethodsGPS2 gene was obtained and the amplified fragment was then cloned into E.coli expression vector pET-28a to construct recombinant plasmid.The recombinant plasmid was transformed into E.coli expression strain BL21(DE3).IPTG induces the expression protein GPS2 protein,and the induction conditions were optimized.The induced product was purified by Ni2+ affinity chromatography,and the purified product was dialyzed with buffer for refolding.The purified protein can be used as antigen,injected to immunize male New Zealand white rabbit to get polyclonal antiserum.The titer and specificity of the rabbit antiserum were detected by ELISA and Western Blotting.ResultsThe E.coli expression vector pET-28a-GPS2 was constructed successfully and the recombinant protein was efficiently expressed and purified.The purified protein was used to immunize male New Zealand white rabbit to get polyclonal antiserum and the ELISA and Western Blot results showed that the high titer of specific polyclonal antiserum.ConclusionGSP2 could be highly expressed in E.coli.Antiserum of GPS2 protein can be obtained by the purified recombinant to analyze its function.

Objective Take frizzled class receptor 4(FZD4) as an example for exploring whether the transmembrane receptor protein is a suitable marker for wound age estimation. Methods A total of 78 Sprague-Dawley rats were divided randomly into the control group and the contusion groups of 4h, 8h, 12h, 16h, 20h, 24h, 28h, 32h, 36h, 40h, 44h, and 48h after injury (n=6). Using a drop-ball technique, a contusion was produced in the right lamb of rats. The samples were dissected from injury zones. Then the expression of FZD4 was detected using immunofluorescence, real-time PCR and western blot, respectively. Results FZD4 was located on the membrane of skeletal muscle cells. Compared to the control group, FZD4 mRNA showed a signiifcant increase (over 2-fold) in 8h, 12h, 36h, and 40h after injury by Real-time PCR (P<0.05), and FZD4 protein showed a statistical up-regulation (less than 2-fold) in 8h, 36h, 40h, 44h, and 48h post contusion by western blotting (P<0.05). Conclusion The expression of FZD4 mRNA and protein are both time-dependent during contused skeletal muscle repair. To some degree, FZD4 mRNA was more suitable than corresponding protein for determining wound age.

Objective To prepare self-assembled thiolated chitosan derivatives gold nanoparticles (CS-GNRs) and carry out the feature tests.Methods CS-GNRs was prepared by chitosan derivatives and GNRs through strong metal sulfur chemical bond between thiols and gold on GNRs surface.Morphology features was tested by transmission electron microscope,dynamic light scattering was adopted to observe the size of nanoparticles.Ultraviolet-visible spectrophotometer was used to detect the optical properties and the property change.Meanwhile,the surface-enhanced Raman scattering (SERS) activity of CS-GNRs was investigated by using crystal violet (CV) as a probe molecular.Results CS-GNRs were in good shape,uniform particle size and good dispersion.The SERS of CV was enhanced,and the enhancement factor of CV adsorbed on CS-GNRs was up to 2×103.Conclusions The nanoparticles have potential application in molecular detection and Raman spectra detection.

Mussel adhesive proteins have attracted increasing interests for their potential use as environmentally friendly bioadhesives in medicine and aqueous conditions. In this study, surface coating analysis, quartz crystal microbalance (QCM), cell and bone tissue adhesion and cytotoxicity assay were used to study the properties of the Perna viridis foot proteins (Pvfp) extract as bioadhesive. The results of coating ability on various materials and QCM analysis revealed that Pvfp extract has comparable or superior adsorbtion ability to that of Cell-Tak (the naturally extracted MAP mixture from Mytilus edulis, and has been commercialized), and also, the cell adhesion ability of Pvfp extract was stronger than that of Cell-Tak and poly-L-lysine. No cytotoxicity was detected using human HeLa and 293T cells. Furthermore, broken bones of mouse could be stuck together by use of Pvfp extract. In bulk-scale adhesion tests, Pvfp extract showed much greater tensile strength than did fibrin glue for conglutinating poly (vinl chloride) sticks and for binding together pig's femur segments. These results suggested that Pvfp extract be an efficient cell and tissue adhesive in biotechnological application and it might be a potential bioadhesive in medical practice.
Animals ; Bone Cements ; isolation & purification ; Bone and Bones ; drug effects ; HeLa Cells ; Humans ; Mice ; Perna ; chemistry ; Proteins ; isolation & purification ; pharmacology ; Swine ; Tissue Adhesives ; isolation & purification

Objective To investigate the clinical effect of irradiated-host bone ends' union after transplantation of pedicled vascularized fibular periosteum in the treatment of Children's tibia sarcoma.Methods From June,2016 to December,2016,there were 5 children of tibia sarcoma,which were 2 boys and 3 girls,aged of 9-15 years (mean,12 years).They were treated by the re-transplantation of extracorporal irradiated segmental autograft,and used ipsilateral pedicled vascularized fibular periosteum cover the ends of irradiated-host bone to shorten the bone union time of irradiated tibia autograft and prevent nonunion.Patients were 3 cases of osteosarcoma,1 of Ewing's sarcoma,and 1 of relapse of Langerhans's cell histocytosis in tibia.The length of resect bone was 14.0-20.0 cm (mean,17.2cm),constitute of 2 osteoarticular resections and 3 intercalary resections.The method of inactivation of bone segment was intraoperative extracorporal irradiation.Regular followed-up were done postoperative.The X-ray and CT were applied to observe the function of affect limb.The bone union time and complication were record.Results All patients were followed-up of 12-18 months (mean,14.2 months).Eight ends of irradiated-host bone in 5 patients healed completely in 7.8 (6-10) months postoperative.The region of ends were covered by periosteum and showed excellent osteogenic power.There was no leg length discrepancy occurred in patients who received intercalary inactivation because of the preservation of growth plate.But the other 2 osteoarticular inactivated patients suffered leg length discrepancy of 1.0 cm and 1.5 cm respectively because of the inactivation of growth plate.At the follow-up of 12 months post-operation,the mean MTSS of affect limb was 25.8(22-28),and the mean of MTSS％ was 86％(73％-93％).Conclusion Transplantation of pedicled vascularized fibular periosteum can promote effectively healing of irradiated tibia bone after replantation in Children,with simple operation and less complications.

Objective To investigate the clinical effect of using pedicled flap to reconstruct skin and soft tis-sue defect after resection of sarcoma around extremities joint. Methods Retrospectively analysis 103 cases of sar-coma around extremities joint who was treated from June, 2012 to June, 2017 and used the pedicled fasciocutaneous flaps or pedicled musculocutaneous flaps to reconstruct the defect after sarcoma resection. There were 61 males and 42 females, with a mean age of 52.3 (14-82 ) years old. Among these patients, there were 32 initial diagnosis, 30 had been resected in other units, and 41 recurrent tumor. There were 13 patients that tumor around wrist:reconstructed by radial wrist upper branch fasciocutaneous flap, dorso-ulnar flap based on supracarpal perforator, and posterior in-terosseous artery flap. Eight patients with tumor around elbow: reconstructed by lateral arm flap and media arm flap. Eight patients with tumor around shoulder: reconstructed by latissimus dorsi musculocutaneous flap and lateral tho-racic flap. Fourteen patients with tumor around hip: rectus femoris musculocutaneous flap, tensor fascia lata musculo-cutaneous flap, and posterior thigh fasciocutaneous flap. Sixteen patients that tumor around knee:reconstructed by an-terolateral low leg flap, and sural calf fasciocutaneous flap. Forty-four patients that tumor around ankle: reconstructed by saphenous neuro-veno-fasciocutaneous flap, sural neuro-veno-fasciocutaneous flap, lateral supramalleolar flap, and medial plantar flap. The defect area after tumor resection were:3 cm ×4 cm-18 cm×25 cm. After surgery, observe the situation and fitness of flap, complication, joint mobility, and tumor recurrence and metastasis. Results Allflaps survived except 6 died or partial died, with a survival rate of 94.2％, of which dead flap were replaced by a new flap or covered by free skin graft. Infection occurred in 4 cases (2 in donor site and 2 in recipient site), were cured by dressing and antibiotic. Except for 12 cases dropped, all rest 91 cases were followed-up by 33 months on average (1-5 years), flaps' shape and texture were good, without swollen and fester, and fit well. Superficial sensibility of direct fasciocuta-neous flaps and musculocutaneous flaps were normal, protective sensation of reverse fascial flaps were recovered. The mobility of affected joint show no difference compared with the other side. No ulcer occurred on flaps of plantar and but-tocks, that helps normal sit position and gait. There were 17 recurrences and 32 metastasis occurred, 21 patients died so far. There was a statistical difference between recurrent cases with first shot(10.3％) second widely resection(11.5％) and recurrent resection(30.6％)(P<0.05). Conclusion Using pedicled flap to reconstruct skin defect after the resection of sarcoma around extremities joint, can get good clinical result, with simple and reliable operation. It is worth to popularize.

Objective: To understand the trends in malnutrition among primary and middle school students of Han nationality in Hainan Province from 2005 to 2019, so as to provide a basis for improving nutrition intervention measures for children and adolescents. Methods: A sample of 32 949 Han nationality primary and middle school students aged 7-18 years old in Hainan Province were investigated in 2005, 2010, 2014 and 2019 based on national survey on student physical fitness and health. The Malnutrition Screening Standard of Schoolage Children and Adolescents was used to screen malnutrition. Statistical analysis was performed using the χ2 test and the χ2trend test. Results: In the four surveys conducted during 2005 to 2019, the prevalence of malnutrition among primary and middle school students were 22.12%, 18.80%, 15.89% and 9.56%, respectively, with an increase of -12.56% and an average annual increase of -5.82%. The decreasing trend of malnutrition by year was statistically significant (χ2trend=600.72, P<0.01), and the proportion of emaciation type was the highest (8.87%-20.15%). The detection rates of malnutrition among all students aged 7 to 18 showed a decreasing trend from 2005 to 2019 (χ2trend=56.44, 60.04, 61.48, 42.49, 51.81, 50.81, 72.86, 101.34, 86.38, 24.81, 17.72, 10.38, P<0.01). From 2005 to 2019, the detection rates of malnutrition in boys were higher than that of girls (in 4 surveys), and that in rural students from 2005 to 2014 of 3 surveys were higher than that in towns (χ2=92.07, 35.16, 25.29, 29.98; 64.35, 4.26, 6.32, P<0.05). Conclusions The malnutrition of Han nationality primary and middle school students aged 7-18 years in Hainan Province show a trend of improvement year by year from 2005 to 2019, despite the overall high detection rate. Wasting is the most common type of malnutrition. The epidemic of malnutrition varies by age, sex and areas. Further targeted measures should be taken to strengthen intervention in the diet of primary and middle school students, to improve the nutritional status of children and adolescents.