BACKGROUND:Poly(D,L-lactide-co-glycolide)(PLGA)may produce lactic acid and glycolic acid when PLGA degrades,thus leading to the acid accumulation and inducing the inflammatory reaction locally.OBJECTIVE:To investigate the effect of lysine,histidine and arginine on regulating the acid accumulation of PLGA copolymer during the degradation.DESIGN:Repeated measurement and experiment.TIME AND SETTING:The experiments were performed in the College of Bioengineering.Chongqing University from July 2006 to August 2007.MATERIALS:PILGA(80:20)was produced by Sigma(USA);Lysine,histidine and arginine(purlty>99%)were purchased from Sigma(USA);Chitosan(deacetylation degree:85%)was purchased from Chengdu Kelong Chemical Reagent Factory;Algin(viscosity:1.05-1.15)was purchased from Tianiin Damao Chemical Reagent Factory.METHODS:Lysine,histidine and arginine were added into PLGA with the proportion of 5%(w/v)and 10%(w/v)respectively.The resultant film sample was put into a bottle with tri-distilled-water for 2-month degradation at 37℃.The pH value of degradation solution was detected by pH meter;Each film sample was taken out and lyophilized 12 hours to get its dry weight and calculate mass loss ratio.Each variety of the solution was sampled three specimens,the average pH value,average initial weight and average finial weight of these three specimens were taken as the indices at each sampling time point,respectively.Accordingly,the regulation effect of basic amino acid was comparexl with that of algin,chitosan and NaHCO3.MAIN OUTCOME MEASURES:The changes of pH value of degradation solution;the mass loss ratio of the composite.RESULTS:Each basic additive could relieve the acid accumulation,among them,NaHCO3 was the strongest,while algin and chitosan showed a lowest capacity,basic amino acid was moderate;The suitable regulation effect could be achieved at a level of 5%lysine.CONCLUSION:Basic amino acid can effectively regulate the acid accumulation after PLGA degrades,and the optimal concentration of lysine is 5%.

With the rapid development of medical genetics,online Medelian inheritance in man (OMIM) manifests a more and more important role in medical genetics teaching.Using the educational form combining ‘ classroom teaching,review writing and seminar’,‘ Query and use of OMIM ’was introduced into the education of medical genetics.Reality practice revealed that this educational practice maintained advanced and timely status of knowledge and deeply activated self-studying and independent thinking ability of students.

BACKGROUND:It is still a research focus on constructing substitution of the human tissues and organs, or producing the alliance for grafting by engineering methods in tissue engineering. Among these researches, it is pivotal to choose appropriate materials. The prepared scaffolds should have suitable tensile strength and mechanical toughness to withstand the various outside forces without being damaged. So, it is very necessary to evaluate the biomechanical properties of candidated materials in tissue engineering, which can supply the references for selecting materials for tissue scaffolds and their designation.OBJECTIVE: To investigate the biomechanical properties of nine kinds of scaffold materials, in order to supply a biomechanical basis for the selection and design of scaffold materials for tissue engineering.DESIGN: A repetitive measurement study.SETTING: College of Bioengineering, Chongqing University.MATERIALS: The materials involved in this study were poly (DL-lactic-co - glycolic acid) (PLGA), sodium polymannuronate, gelatine, chitosan, collagen, acellular porcine dermis (APD), acellular vascular matrix (AVM),APD-PLGA, AVM-PLGA, modified gelatine and chitosan.METHODS: All the experiments related to this study were completed in the Biorheology laboratory of the College of Bioengineering, Chongqing University from April 2006 to March 2007. The nine materials above were prepared, gelatine and chitosan were modified. Stress-strain testing was performed at 10 mm per minute by a material testing machine (INSTRON 1011, USA). The Yang's modulus was calculated in the range of 0.005 to 0.02, the ultimate strain and stress were also obtained.MAIN OUTCOME MEASURES: The ultimate strain, ultimate stress and Yang's modulus of the nine materials were analyzed.polymannuronate ＞ AVM-PLGA ＞ collagen ＞ gelatine (P ＜ 0.05). The rate of burst straining of chitosan and PLGA were greater than those of other materials, 133% and 276% respectively (P ＜ 0.05). In addition, after being combined with ultimate stresses of APD and APD-PLGA were greater than that of other materials, i.e., their burst strengths were greater than those of other materials. The data also indicated that the burst strength of APD-PLGA was a little greater than that of APD (P ＞ 0.05). The burst strengths of gelatin, chitosan, and collagen were similar at the range of 7.67 to 9.51 MPa (P ＞ 0.05). The burst strengths of collagen and sodium polymannuronate were from 1.16 to 1.40 MPa, which were the least among all the materials. At the same time, being combined with PLGA, the burst strength of AVM-PLGA greatest, i.e., its rigidity was the greatest. The rigidity of APD was the least. After combined with PLGA, the rigidity of AVM and APD were increased (P ＜ 0.05), and corresponded with PLGA (P＞ 0.05). Except for gelatin, the order of rigidity in the materials was AVM-PLGA ＞ PLGA ＞ APD-PLGA ＞ AVM ＞ chitosan ＞ sodium polymannuronate ＞ collagen ＞ APD.CONCLUSION: AVM and APD have good biomechanical properties, which are very different from the water-soluble collagen. It is promising to improve the biomechanical properties of sodium polymannuronate, gelatin and chitosan by the complex of PLGA.

Objective To explore the characteristic of ACE gene I/D polymorphism in Han broad jumpers .Methods Distribu‐tion of ACE gene I/D polymorphism for broad jumpers was analyzed by PCR ,DNA sequencing ,Hardy‐Weinberg and SPSS ,and the results were compared with that of normal people .Results There were II ,DD and ID in gene ACE 16 ,and the Hard‐Weinberg re‐sults showed that the subjects were group representative .The ACE DD genotype and D allele in broad jumpers was statistically higher than normal controls (P<0 .05) .Conclusion The results suggest that ACE DD genotype and D allele are associated with training sensitivity of broad jumpers and could be the molecular marker for athletes choosing genetically .

OBJECTIVETo explore the effects of CXCR7 knock-down by CXCR7-shRNA lentiviral vector on the proliferation and invasion of human hepatoma carcinoma cells in vitro.

METHODSCXCR7-shRNA lentiviral vector was transfected into hepatocellular carcinoma HCCLM3 cells. The changes in mRNA and protein expression of CXCR7 in the transfected cells were investigated using real-time PCR and Western blotting, respectively, and MTT assay was employed to assess the cell proliferation changes. In vitro adhesion assay and transwell chamber test were used to observe the adhesion and invasiveness of HCCLM3 cells, respectively.

RESULTSTransfection of HCCLM3 cells with CXCR7-shRNA lentiviral vector resulted in a significantly decreased expression of CXCR7 at both mRNA and protein levels (P<0.01) and obvious suppression of the cell proliferative activity (P<0.05). CXCR7-shRNA also significantly suppressed the invasiveness and adhesion of HCCLM3 cells (P<0.01).

CONCLUSIONCXCR7 knock-down can significantly inhibit the proliferation and invasiveness of human hepatoma carcinoma cells in vitro, suggesting the value of CXCR7 as a potential target for hepatoma carcinoma therapy.

Carcinoma, Hepatocellular ; genetics ; pathology ; Cell Line, Tumor ; Cell Proliferation ; Genetic Vectors ; Humans ; Lentivirus ; genetics ; Liver Neoplasms ; genetics ; pathology ; RNA, Small Interfering ; genetics ; Receptors, CXCR ; genetics ; Transfection

The effect of the endophytic fungi Botrytis sp. (C1) or Chaetomium globosum (C4) on the drought resistance of Chrysanthemum morifolium was studied. Ch. morifolium plantlets were inoculated with C1, C4 and cultured in the pots for 60 days, then the plantlets were stressed by 0%, 10%, 20%, 30%, 40% PEG6000 respectively in order to simulate different drought conditions. Biomass, the activities of SOD, POD, PAL, the contents of MDA and soluble protein of each group were determined. The results showed that endophytic fungi groups grew better than the control (without inoculation endophytic fungi). With the increasing of the concentration of PEG6000, the biomass of Ch. morifolium of each groups decreased, while the biomass of fungi groups was significantly higher than that of control, moreover C4 group higher than C1 group. With the concentration of PEG increasing, the content of MDA of each group increased too, while POD activity and soluble protein content of all treatments increased at first and then decreased. SOD activity and PAL activity of the control were increased with the increase of PEG concentration, but SOD activity of the two fungi groups were stable. After been stressed by different concentrations of PEG, MDA content of two fungi groups were always lower than the control, while SOD activity, POD activity, PAL activity and soluble protein content were higher. In conclusion, endophytic fungi can increase the drought resistance of Ch. morifolium.
Biomass ; Botrytis ; drug effects ; growth & development ; isolation & purification ; Chaetomium ; drug effects ; growth & development ; isolation & purification ; Chrysanthemum ; drug effects ; metabolism ; microbiology ; Droughts ; Peroxidases ; metabolism ; Polyethylene Glycols ; pharmacology ; Stress, Physiological ; drug effects ; Superoxide Dismutase ; metabolism

Objective:To prepare polyvinyl alcohol (PVA) and hydroxyapatite (HA) composite embolization microspheres and investigate their physicochemical properties.Methods:PVA/HA composite embolization microspheres were prepared by reverse suspension polymerization, using PVA and HA as dispersed phases, liquid paraffin containing sorbitan fatty acid ester as the continuous phase, and glutaraldehyde as the cross-linking agent. The morphology, particle size distribution, and microscopic morphology of PVA/HA composite embolization microspheres were observed by optical microscopy and scanning electron microscopy. The chemical structure of PVA/HA composite embolization microspheres and the elasticity, drug loading, and drug release properties of PVA/HA composite bolus microspheres were characterized by Fourier infrared spectroscopy.Results:The PVA/HA composite embolization microspheres were internal, porous round spheres with a particle size distribution of 50-300 μm. The elastic properties of PVA/HA composite embolization microspheres were(13.6±0.145) kPa, which was 2.28 times that of PVA microspheres, and the drug loading capacity and encapsulation efficiency were (76.80±1.22) mg/g and (38.4±12.7)%, respectively. The maximum cumulative release rate of the microspheres within 7 days was (7.37±0.101)%, and the maximum cumulative release was (256.2±9.8) μg.Conclusions:PVA/HA composite embolization microspheres have good mechanical properties and drug-loading and drug-releasing properties, which provide an important reference for their use as medical devices.