BACKGROUND:The form and structure of antigen-extracted xenogeneic cancel ous bone through series of physical and chemical treatment are similar to human tissue. OBJECTIVE:To detect the biocompatibility of antigen-extracted xenogeneic cancel ous bone matrix prepared by three different ways. METHODS:The antigen-extracted xenogeneic cancel ous bone scaffold materials which were prepared through physical, chemical and physical-chemical combined methods and hydroxy apatite biological ceramic materials were implanted into the dorsum subcutaneous tissue. Histological observation was done at 4, 8 and 12 weeks after surgery. The antigen-extracted xenogeneic cancel ous bone scaffold materials which were prepared through physical, chemical and physical-chemical combined methods respectively was used to culture sheep bone marrow mesenchymal stem cells for 7 days. Cel adhesion, growth, proliferation and stroma secretion were observed. RESULTS AND CONCLUSION:At 4 weeks after surgery, a strong inflammatory reaction was detected around materials in four groups. At 12 weeks, the xenogeneic bone materials prepared through physical and physical-chemical combined methods and hydroxy apatite biological ceramic materials internal pore and surrounding tissue inflammation disappeared basical y, with the presence of thimbleful inflammation cells. The material degradation was more than at 8 weeks. The xenogeneic bone materials prepared through chemical methods material internal pore and surrounding tissue inflammation stil existed, suggesting that the xenogeneic bone materials prepared through physical and physical-chemical combined methods exhibited good histocompatibility. A smal amount of orderly osteoblasts existed around hydroxy apatite biological ceramic materials and physical-chemical prepared materials, with a smal amount of bone. These suggested that there was a tendency for ectopic bone formation. The xenogeneic cancel ous bone materials prepared through physical or physical-chemical combined methods have better cytocompatibility. However, scaffold materials prepared through chemical method have poor cytocompatibility and they are not qualified for the safety standards of biological materials.

Objective:To investigate Bcl-2 and Bax gene expression in acute myelogenous Leukemia and the relationship between Bcl-2/Bax ratio and drug resistance.Method:Expression of Bcl-2、Bax was detected by immunohistochemical method while drug resistance of AML was detected by cell culture and MTT assay.Results:A high expression of Bcl-2 and a low expression of Bax were detected in AML,respectively,and the ratio between Bcl-2 and Bax was significantly higher than that in normal control (P＜0.01). The ratio in those who are resistant to chemotherapy was significantly higher than that in those sensitive to chemotherapy (P＜0.05).The responsiveness to chemotherapy of those with a high ratio was poorer than thos with a low ratio (P＜0.05).Conclusion:The alteration of Bcl-2 and Bax played certain role in the development of drug resistance in AML,the test of Bcl-2/Bax ratio may have great significance in choice of chemotherapeutic agents and also provide important information for outcome prediction.

The conduction of performance appraisal in the hospital is of great significance to the perfection of the appraisal system and the improvement of the managerial efficiency of the hospital. The authors suggest that in the process of establishing an appraisal system of hospital performance, it is necessary to use for reference enterprises' experience in performance appraisal and the theories of performance management. Firstly, single-faceted pursuit of economic benefits should be avoided, the establishment of an external hospital appraisal system and the establishment of an internal hospital appraisal system should be combined, and attention should be paid to the overall application of performance appraisal in performance management. Secondly, in light of their own experience in hospital management, the authors put forward the suggestion of establishing a performance appraisal system of three levels: the hospital , the department and the post. They also argue that attention should be given to the selection of comprehensive appraisal methods, continuous communication about performance, and readjustment in a timely manner.

OBJECTIVE To investigate the drug sensitivity situation of Acinetobacter baumannii(ABA) in 3 years to instruct clinical application of the antibiotics.METHODS The drug sensitivity test data of the 428 A.baumannii(ABA) strains from 2006 to 2008 were analyzed retrospectively.RESULTS It was showed from the drug sensitivity test in vitro that the most sensitive drug for A.baumannii(ABA) was imipenem,which resistance rate was 11.3-34%.The resistance rate to amikacin was 29.8-49.5% and to penicillins was is 57.7-91%,the resistance rate to of penicillins drugs was 54-74.5%.The resistance of ABA to ampicillin,cefazolin,cefpodoxime and Cefoxitin was over 91%,and showed the multi-drug resistance features.CONCLUSIONS According to the result of drug sensitive test,the most effective antibiotics are imipenem,meropenem and polymyxin B sulfate.

BACKGROUND: The conical telescopic crown denture has a better long-term effect on dentition defects of few remaining teeth than the traditional removable denture. However, there are few studies to analyze the application of these two kinds of repair methods using the finite element method. OBJECTIVE: To compare the stress distribution of the isolated abutment tooth repaired using the conical telescopic crown denture and traditional removable denture. METHODS: Two-dimensional images of the mandible and dentition in healthy adults were scanned by CT. Three-dimensional finite element models of conical telescopic crown denture and traditional removable denture were established in the mandible only with the bilateral canines. Under the same vertical and oblique loadings, the maximum equivalent stress of the abutment, periodontal membrane or edentulous alveolar ridge was compared between two repair methods. RESULTS AND CONCLUSION: Under the vertical and oblique loadings, the total stress of abutment and periodontal membrane in the traditional removable denture was higher than that in the conical telescopic crown denture and the stress in the corresponding ring was concentrated obviously; the total stress of edentulous alveolar ridge in the conical telescopic crown denture was slightly larger than that in the traditional removable denture, but the stress was wel -distributed and concentrated in a smal area. Under the oblique loading, the total stress of abutment, periodontal membrane and edentulous alveolar ridge was higher than that under the vertical loading in these two dentures, and the stress was concentrated in the periodontal membrane of lingual neck, but the total stress in the traditional removable denture was larger, with a wider concentration range. These findings indicate that the stress on the supporting tissue of conical telescopic crown denture is more evenly distributed within a smal er range than that of traditional removable denture, and the former is more fit for the health of abutment, periodontal tissues and edentulous alveolar ridge.

BACKGROUND: Hydroxyapatite/β-tricalcium phosphate biphasic ceramic bone has good cel compatibility, but its mechanical properties are poor. OBJECTIVE: To construct chitosan/ or calcium alginate/biphasic ceramic bone scaffolds and to detect their mechanical properties and cytocompatibility. METHODS: Different concentrations of chitosan (2%, 4%, 7%, 10%) or calcium alginate (3%, 4%, 5%, 7%) were mixed with biphasic ceramic bone to prepare chitosan/biphasic ceramic bone scaffold and calcium alginate/biphasic ceramic bone scaffold. Their morphology and structure, coagulation time, anti-dissolution properties, shear force, compressive strength and cel compatibility were detected. RESULTS AND CONCLUSION: (1) Coagulation time: with the concentration increase, the initial and final setting time of these two kinds of composite scaffolds were prolonged to some extent. (2) Scanning electron microscopy: these two kinds of composite scaffolds showed porous microstructures with different pore sizes. (3) Anti-dissolution properties: the calcium alginate/biphasic ceramic bone scaffold (3%, 4%, 5%, 7%) and chitosan/biphasic ceramic bone scaffold (7%, 10%) had good anti-dissolution properties in the liquid. (4) Mechanical strength: with the concentration increase, the shear force and compressive strength of the calcium alginate/biphasic ceramic bone scaffold were reduced. (5) Cel compatibility: the cytotoxicity of chitosan/ or calcium alginate/biphasic ceramic bone scaffolds was graded as 0-1 or 2-3, respectively. These results show that the chitosan/biphasic ceramic bone scaffold has better mechanical properties and cel compatibility than the calcium alginate/biphasic ceramic bone scaffold.

BACKGROUND:Xenogeneic bone has a natural porous structure that is similar to human bone. In the treatment of bone defects, the porous structure is helpful to guide bone regeneration, but different degrees of immune responses wil be caused during the implantation process. OBJECTIVE:To prepare a freeze-dried antigen-extracted sheep cancelous bone scaffold and to evaluate its biocompatibility. METHODS: The sheep vertebral cancelous bone was colected to prepare two kinds of antigen-extracted heterologous bone scaffolds that were treated with chemical methods as chemical group and treated with chemical methods+cryopreservation at a-80℃ refrigerator for 4 weeks+drying in vacuum apparatus+60 RESULTS AND CONCLUSION:Freeze-dried bone had no cytotoxicity, no acute toxicity and heat reaction, and was negative for the intracutaneous stimulation test. The scaffold in the chemical group had cytotoxicity and mild irradiation as freeze-dried bone group. (1)Cytotoxicity test: Bone marrow mesenchymal stem cels isolated from sheep were cultured in extracts of the chemical group, free-dried bone group and Dulbecco’s modified Eagle’s medium/Ham’s nutrient mixture F-12. (2) Heat reaction and acute toxicity tests: Extracts from the chemical group, freeze-dried bone group and normal saline were respectively injected into the ear vein of rabbits. (3) Intracutaneous stimulation test: Extracts from the chemical group, freeze-dried bone group and normal saline were respectively injected subcutaneously into the back of rabbits. Co acute toxicity reaction, sent heat source and had mild irritation. Results show that after freeze drying processing, the sheep vertebral cancelous bone has good biocompatibility, can meet the requirements of bone tissue engineering, but the bone that through chemical processing exhibits a relatively poor biocompatibility that cannot achieve the safety standard of biological scaffold materials.

BACKGROUND:Porcelain jacket crowns have achieved good results in the repair of porcelain ceramic crown and bridge colapse.
OBJECTIVE:To test the bond strength of single porcelain jacket crown, thus determining the feasibility of clinical application of repairing colapsed crown and fixed bridge by porcelain jacket crown, and meanwhile to discuss the influence between blastsanding and silane coupling agent treatment on the metal bonding strength in the repair of porcelain fracture.
METHODS: The porcelain jacket crown was cast in the same shape from disk-shaped waxpatterns. Twenty specimens were chosen without blowholes and casting defects and they were al routinely burnished and cleaned in an ultrasonic bath and dried using an oil-free air stream stand-by. Then we randomly divided the specimens into four groups: specimens were treated with nothing (control), sandblast, silane coupling agent and sandblast+silane coupling agent, respectively. Each of the specimen was bonded with Poly-F Plus. AG-10TA universal testing machine was used to test the tensile strength.
RESULTS AND CONCLUSION:The tensile bond strength of control, sandblast, silane coupling agent and sandblast+silane coupling agent groups respectively were (0.68 0.04), (1.00 0.02), (1.31 0.08), and (1.09 0.04) kN. There were significant differences between groups (P < 0.01). In the control group, the metal surface was smooth, showing some irregular smal superficial veins. In the sandblast group, the metal surface showed irregular scaly protrusions conducive penetrate adhesives. In the silane coupling group, the metal surface manifested a honeycomb structure in favor of chimeric adhesives. The sandblast+silane coupling agent group showed some metal projections ranging in size, on the rough metal surface, which was conducive to bond. Porcelain jacket crown applied to repair colapsed crown and fixed bridge is feasible. Sandblasting and silane coupling agent can improve bond strength of porcelain jacket crown. The bond strength of metal specimens treated with silane coupling agent is the best folowed by the sandblasting+silane coupling agent.

BACKGROUND:Some studies have indicated that different genes in tooth germ tissue play a role at different time, contributing to tooth germ development.
OBJECTIVE:To observe the expressions of dentin matrix protein 1, enamel protein, col agen I and homeobox gene 1 at different stage of in vitro culture of tooth germ cells.
METHODS:RNA from tooth germ cells was extracted at days 1, 3, 6 of in vitro culture. After reverse transcription, real-time quantitative PCR detection was adopted to measure relative expression of dentin matrix protein 1, enamel protein, col agen I and homeobox gene 1 mRNA.
RESULTS AND CONCLUSION:Dentin matrix protein 1, enamel protein, and col agen I mRNA expressions increased with culture time, and reached the peak at day 3 (P<0.05), whereas homeobox gene 1 mRNA decreased with culture time (P<0.05).

50.0%.CONCLUSION:The extensive use of antibacterials results in increased drug resistance,while rational use of antibiotics is the key of decreasing drug resistance and multidrug resistance.It is of great importance to analyze the variation of bacterial drug resistance in area hospital.