In order to improve the interfacial bonding strength of hydroxyapatite/polyurethane implanted material and dispersion of hydroxyapatite in the polyurethane matrix, we in the present study synthesized nano-hydroxyapatite/polyurethane composites by in situ polymerization. We then characterized and analyzed the fracture morphology, thermal stability, glass transition temperature and mechanical properties. We seeded MG63 cells on composites to evaluate the cytocompatibility of the composites. In situ polymerization could improve the interfacial bonding strength, ameliorate dispersion of hydroxyapatite in the properties of the composites. After adding 20 wt% hydroxyapatite into the polyurethane, the thermal stability was improved and the glass transition temperatures were increased. The tensile strength and maximum elongation were 6.83 MPa and 861.17%, respectively. Compared with those of pure polyurethane the tensile strength and maximum elongation increased by 236.45% and 143.30%, respectively. The composites were helpful for cell adhesion and proliferation in cultivation.
Biocompatible Materials ; chemistry ; Cell Adhesion ; Cell Line ; Durapatite ; chemistry ; Humans ; Polymerization ; Polyurethanes ; Tensile Strength ; Transition Temperature

Objective To investigate abnormal protein expression of matrix metalloproteinase-9 (MMP-9), vascular endothelial growth factor (VEGF) and proliferating cell nuclear antigen (PCNA) in human gastric adenoearcinoma, and further reveal the clinical significance. Method The MMP-9, VEGF and PCNA proteins expression was determined by immunohistochemistry staining in 45 gastric adenocarcinoma tissues, 45 adjacent specimens and 10 normal gastric mucosa tissues via tissue arrays accordingly. The relationship of these protein expression with differentiation degree, development and progression of gastric adenocarcinoma were also analyzed. Results Positive rates of MMP-9, VEGF and PCNA in gastric adenocarcinoma, adjacent specimens and gastric normal mucosa were as follows: MMP-9, 82.2%(37/45), 64.4% (29/45), 30.0% (3/10) (P=0.019); VEGF, 73.3% (33/45), 62.2% (28/45), 30. 0% (3/10) (P=0.029); PCNA,84.4% (38/45), 71.1% (32/45), 10.0% (1/10) ,there were statistically significant difference (P = 0. 001). The positive rates of MMP-9, VEGF and PCNA in well-differentiated adenocarcinoma, moderately differentiated adenocarcinoma and poorly differentiated adenocarcinoma were as follows: MMP-9,70.0%(7/10), 80. 0% (8/10), 88.0%(22/25), there were statistically significant difference (P=0.015);VEGF, 50.0%(5/10), 60.0% (6/10), 88.0% (22/25), there were statistically significant difference (P =0.000);PCNA, 60.0% (6/10) ,90.0% (9/10) ,92.0% (23/25) ,the difference is significant statistically (P = 0.004). The expression of MMP-9, VEGF and PCNA showed positive relationship with each other by rank correlation analysis (P < 0. 05). Conclusion Tissue arrays technology is effective tool to analyze the expression of cancer related proteins in gastric adenocarcinoma. The expression of MMP-9, VEGF and PCNA proteins participates in the tumorigenesis and development process of gastric adenocarcinoma, and these can be used as indexes to evaluate prognosis in clinical.

Objective To establish a double-antibody sandwich ELISA for the rapid detection of shiga toxin typeⅡ ( StxⅡ) in shiga toxin-producing Escherichia coli ( STEC) infection. Methods A pool of murine hybridomas was used to screen out the optimal antibody pair for the establishment of double-anti-body sandwich ELISA. The established ELISA system was used to detect StxⅡin the culture supernatants of 16 clinical strains of STEC. Specificity and sensitivity of the established ELISA system were also evaluated. Results Two antibodies, S2D8 and S2C6, were successfully screened out, based on which the double-anti-body sandwich ELISA was set up. StxⅡand its variants rather than StxⅠwas detected in the culture super-natants of STEC with a lowest detection limit of 4 ng/ml. Its performance was consistent with that of commer-cial colloidal gold test kit, indicating the characteristics of good specificity and sensitivity. Conclusion The S2D8/S2C6-based ELISA laid a foundation for researches which designates the shiga toxin as a potential can-didate on the diagnosis and therapy of STEC infection.

Objective:To explore the application effect of standardized patient combined with situational simulation teaching in the course of Intensive and Critical Diseases Care among higher vocational college students.Methods:A total of 66 nursing students in direction of intensive care from Batch 2015 and 60 ones from Batch 2016 were selected as the control group and the experiment group respectively. The control group adopted traditional teaching method, while the experiment group adopted the model of standardized patient combined with situational simulation teaching on the basis of traditional teaching methods. Before teaching, we designed the standard cases of the course, set up and trained the standardized patient team members. Then the standardized patient combined with situational simulation teaching was applied to the experimental teaching of the course. At the end of the course, the comparison of the theoretical examination score and the operational examination score of the two groups of students was made, and the self-designed questionnaire survey for the experimental group was used to evaluate the teaching effect.Results:The theoretical examination score [(82.80±4.17) points] and the operational examination score [(85.90±1.85) points] of students in the experiment group were higher than those of students in the control group [(80.74±3.15) points vs. (83.82±1.91) points], with significant differences ( P<0.01). The results of self-designed questionnaire survey showed that more than 90.0% of the students from the experiment group thought that this teaching mode could improve their interest in learning and subjective initiative; more than 76.7% thought that this teaching mode could improve their own abilities such as observation of disease changes, communication, teamwork and clinical thinking; more than 93.3% recognized the application of this teaching mode. Conclusion:The application of standardized patient combined with situational simulation teaching could improve the theoretical knowledge and operational skills of the students, and could also train the students' comprehensive quality such as clinical thinking, emergency handling ability, communication ability and so on, so as to improve the teaching effect.

Objective To approach the changes of cytosol phospholipase A2α(cPLA2α)and nitric oxide (NO)in patients with chronic obstructive pulmonary disease(COPD)and its significance. Methods One hundred patients with COPD admitted into Department of Critical Care Medicine of Affiliated Wuqing Traditional Chinese Medicine(TCM)Hospital of Tianjin University of TCM were enrolled,and according to the COPD severity grading standards,they were divided into mild group(25 cases),moderate group(25 cases),severe group(26 cases) and extremely severe group(24 cases);simultaneously,90 cases with normal pulmonary function who had taken health examination were chosen and assigned to the healthy control group. The cPLA2α level was detected by enzyme linked immunosorbent assay(ELISA),the level of uric acid(UA),total cholesterol(TC),triacylglycerol (TG)were detected by enzymatic method,and serum NO metabolites(NOx)level was detected by nitrate reductase method. Results Compared with the healthy control group,the serum levels of cPLA2α and UA in patients with different severity of COPD were significantly increased;along with the increase of patient's COPD grade of severity,the cPLA2α,UA levels were gradually increased,while NOx level was gradually decreased in mild, moderate, severe, extremely severe groups〔cPLA2α(ng/L):125.60±8.17, 155.20±6.42, 190.20±9.32, 255.80±11.28 vs. 88.50±7.99;UA(μmol/L):381.23±32.22,434.95±87.71,464.81±52.65,487.45±82.61 vs. 241.95±52.33;NOx(μmol/L):59.90±17.52,45.60±6.17,38.20±4.08,25.70±3.04 vs. 74.90±18.31,all P<0.05〕. The differences in blood cPLA2αand serum NOx level among groups with different severity of COPD were of statistical significance(P<0.05). The levels of TC,TG among these different severity groups had no statistical significance(all P>0.05). The cPLA2αand NOx levels presented significant negative correlation(rs=-0.798,P=0.013). Conclusion The combined examination of blood cPLA2αand serum NOx levels can evaluate the severity degree of COPD patients,and cPLA2αcan be used as a new target index for COPD grading.

The functional hemocompatibility between fibrinogen (FIG) and a novel vascular stent material (Ti-O film fixed with albumin and heparin) was investigated as follows: (1) Preparing the new biologic material (Ti-O) film; (2) Coating albumin and heparin on the Ti-O film; (3) Testing platelets (PL) adsorption; (4) Determining FIG adhesion number by use of enzyme linked immunoassay (ELISA); (5) Implanting the films from the test group of Ti-O film and from the comparison group of stainless steel (SS) film into the left and right femoral arteries respectively in 4 dogs. It was proved that albumin and heparin were fixed on Ti-O film. After 6 months, the femoral arteries of the dogs were resected. In the test group of Ti-O film coated with albumin and heparin, few PL adhered to the coat, their form did not change, and no thrombus was found by scanning electron microscopy; the result was better than that of plain Ti-O film, and was much better than that of SS film. Ti-O maintained normal transformation condition of FIG, and no C terminal of gamma chain in FIG was revealed. As it is known whether the hemocompatibility of a biomaterial is good depends upon its adsorption of FIG, and Ti-O has excellent reaction on albumin and heparin by chemical processes. In this study, the Ti-O film coated with albumin and heparin further reduced the absorption of FIG and PL when compared against the plain Ti-O film. So the Ti-O film coated with albumin and heparin has the insistent and permanent anticoagulant character.
Albumins ; chemistry ; Animals ; Coated Materials, Biocompatible ; pharmacology ; Dogs ; Fibrinogen ; chemistry ; Heparin ; chemistry ; Materials Testing ; methods ; Prosthesis Design ; Stents ; Surface Properties ; Titanium ; chemistry

We developed a rapid method to detect Cu2+and glutathione(GSH)based on the fluorescence quenching-recovery properties of graphene quantum dots(GQDs),which were synthesized by the gentle oxidation of graphite powder.The results revealed that the fluorescence intensity of GQDs versus concentration of Cu2+and GSH had good linearity, with the detection limits of 0.01 and 0.1 mmol/L, respectively.The fluorescence quenching was linearly proportional to the concentrations of Cu2+ranging from 1.0 to 10.0 mmol/L;the fluores-cence intensity was linearly enhanced with the concentrations of GSH ranging from 0.1 to 1.0 mmol/L.In addi-tion,the method was successfully applied to the determination of real samples with recoveries falling between 93％-101％ and 96％-107％,respectively.This method is simple,accurate and precise.There was no interference with other familiar co-existing metal ions and potential materials.

Blocking the programmed death-ligand 1 (PD-L1) on tumor cells with monoclonal antibody therapy has emerged as powerful weapon in cancer immunotherapy. However, only a minority of patients presented immune responses in clinical trials. To develop an alternative treatment method based on immune checkpoint blockade, we designed a novel and efficient CRISPR-Cas9 genome editing system delivered by cationic copolymer aPBAE to downregulate PD-L1 expression on tumor cells specifically knocking out Cyclin-dependent kinase 5 () gene . The expression of PD-L1 on tumor cells was significantly attenuated by knocking out , leading to effective tumor growth inhibition in murine melanoma and lung metastasis suppression in triple-negative breast cancer. Importantly, we demonstrated that aPBAE/Cas9-Cdk5 treatment elicited strong T cell-mediated immune responses in tumor microenvironment that the population of CD8 T cells was significantly increased while regulatory T cells (Tregs) was decreased. It may be the first case to exhibit direct PD-L1 downregulation CRISPR-Cas9 genome editing technology for cancer therapy. It will provide promising strategy for preclinical antitumor treatment through the combination of nanotechnology and genome engineering.