Background Whether the wearing of bifocal lenses can delay the development of myopia in school childhood is in controversy.To assess the effect of bifocal lenses using evidence-based medicine method is of important significance.Objective Present study was to compare the effect of bifocal lenses with single vision lenses in retarding myopia progression in school-aged myopic children.Methods This was a evidence-based medicine study.The systematical literature search was performed from MEDLINE(1966 to October 2010),EMBASE(1974 to October 2010),Cochrane Library,Chinese Biomedical Database(1978 to October 2010),and Chinese Clinical Trial Registry combined with hand searching of related bibliographies of journals and books were applied to collect the randomized-controlled clinical trial about bifocal lenses.Screening,evaluation and data extraction of the retrieved literature were performed by two investigators independently.Mata-analysis was used to assess the progression of refraction and axial length among included randomized clinical trials.Results Three high-quality randomized-controlled clinical trials meeting the inclusion criterion were included in this meta-analysis.The results showed that the weighted mean difference in progression of refraction was 0.22D between bifocal lenses and single vision lenses(95% CI:-0.24-0.67),and the difference was statistical insignificance(P=0.35).The weighted mean difference in progression of refraction during the follow-up durations of 6,12,18,24 and ＞30 months were 0.15(95% CI:-0.09-0.38),0.17(95% CI:-0.05-0.39),0.42(95% CI:-0.14-0.98),0.23(95% CI:-0.21-0.66) and 0.03(95% CI:-0.40-0.46),respectively without statistical significance.The weighted mean difference in elongation of axial length between two interventions was -0.17mm(95% CI:-0.26-0.08) with a statistically significance(P=0.000).Conclusion Based on currently available studies,bifocal lenses could not significantly slow the progression of myopia in myopic school-aged children in comparison with single vision lenses.Because only few high-quality studies are currently available,this conclusion need to be supported by more large-sample-size clinical trials.

Objective To investigate the effect of brain-derived neurotrophic factor (BDNF) gene modified neural stem cells (NSCs)transplantation on cerebral ischemic injury in rats.Methods NSCs from newborn rat hippocampus were isolated,cultured in a medium containing fibroblast factor (FGF) in vitro. Their proliferation and differentiation were detected by immunohistochemistry.Virus vectors pLXSN-BDNF were built and BDNF were transfected into NSCs.Biological activity were detected to obtained engineering stem cells of BDNF protein with secretary activity.Middle cerebral artery occlusion (MCAO) models were made and transplanted with NSCs-BDNF by stereotaxic technique.The effect of transplantation on MCAO models was evaluated histologically and behaviorally.Results Statistical analysis showed that the behavioral performance of the animals improved after transplantation (Longa mark being 1.343?0.293 four weeks after stem cell transplantation).The number of hippocampal dentate gyrus neurons increased to 87.5%?6.6% , four weeks after stem cell transplantation on Nissle stained hippocampal sections,which was significantly different from that of controls.Positively BrdU stained neural stem cells revealed by immunohistochemistry in the cultured cells and in the transplanted brain sections,indicated that the engineering cells transplanted had survived in the host brain and began to proliferate.Conclusion Transplantation of BDNF genetically modified NSCs can effectively promote the recovery from cerebral ischemic injury.

The recombinaut porcine insulin precursor(PIP)produced by Pichia pastoris in shake-flask and 501.fermenter was investigated respectively.The results indicated that 60h induction time length and 2.0%～2.5% methanol addition every day was optimum in shake- flask.The process in 50L fermenter was consisted of batch,feed-batch and induction phases.The relationship between dry cell weight(y) and culture time (t) in growth phase(batch and feed-batch phase)could be described by model y=0.6525e~(0.1907t).Glycerol and ammonia were almost used for cell growth and maintain,and no by-product was observed in batch and fed-batch phase Only 80% ammonia and 70% methanol were used by cell in induction phase.By comparison the results of shake-flask and 50L fermenter,it was concluded that the limit- ing factor in the fermentation of shake-flask and 50L fermenter was dissolved oxygen(DO)and.carbon source,respectively.When scaling the result of shake-flask to 501.fermenter,the control strategy was adapted for 50L fermenter by increasing the feed rate of methanol and the maximum PIP concentration reached 1.72 g/L.

Immobilized penicillin acylase was used for bioconversion of penicillin G into 6-APA in aqueous two-phase systems consisted of a light-sensitive polymer PNBC and a pH-sensitive polymer PADB.Partition coefficients of 6-APA was found to be:about 5.78,in the presence of 1% NaCl.Enzyme kinetic showed that reaction reached equilibrium at 7h or so.The 6-APA mole yields were 85.3%(pH 7.8,and 20 ℃) and this value was about 20%higher than control in reaction of single aqueous phase buffer.Partition coefficient of penicillin G(Na) washardly changeable,while partition coefficient of product,6-APA and phenylacetate acid was significantly changeable.Reason is due to Donnan effect of phase systems andhydrophobicity of products.The change of partition coefficients of products also affects bioconversion yield of products.In the aqueous two-phase systems,substrate,penicillin G,products 6-APA and phenylacetate acid are biased in top phase,while immobilized penicillin acylase is completely partitioned in bottom.Substrate,penicillin G enters into bottom phase,and it is catalyzed into 6-APA and phenylacetate acid,then the products enter into top phase.Finally,inhibition of substrate and products is removed to result in improvement of products yield.Moreover,immobilized enzymehashigher efficiency than immobilized cells and occupy smaller volume.Comparing with free enzyme,immobilized enzymehashigher stability,longer use life,completely partitioned in bottom phase and recycle.Bioconversion in two-phase systems using immobilized penicillin acylase showed outstanding advantage.The light-sensitive copolymer forming aqueous two-phase systems could be recovered by laser radiation at 488 nm or filtrated 450 nm light,while pH-sensitive polymer PADB could be recovered by isoelectric point(pH 4.1).The recovery of the two copolymers was 95%~99%.

Based on the optimized technology on 50L scale, B subtilis 754# was used to manufacture guanosine on pilot scale (12M 3) and plant scale (100M 3) to give the production of 29 4g/L and 21 4g/L successively Through scale down the process of plant scale to pilot scale, based on the theory of dynamic metabolic flux, DO was found to be another key factor that limited the scale up process After conquering the DO limitation, the optimized technology was successfully scaled up to plant scale and the production was further increased by 18% to 25 2 g/L

In this assay, the reaction kinetics, optimum temperature, pH and various influential factors of ATP microbial rapid detection reagent by bioluminescence were studied. The results showed that it's enough for detection system to have 40 ~ 50?g/mL D-Luciferin. The light production decreased fastest in the first minute of reaction, then began to decay slowly. The optimal reaction temperature was 24℃~25℃and the optimal pH was pH 7.2 -7.4 in the reaction system. In addition, when stored at 4℃for 45h, the dissolved reagent solution could keep its 86% activity. When preserved at 25℃, the enzyme activity decreased less for 1h, and degraded gradually as time went by and only left 53. 5% of its activity after 6. 5h. While stored at 33℃, the enzyme activity decreased quickly with the time and only left 59. 1% after 1. 5h. The result indicated that storage temperature was a very important influential factor to the activity of reagent Meanwhile, different chemical substance such as acid, alkali, salt and surfactants inhibited the ATP bioluminescent reaction. When the concentration of NaCl reached 1. 5g/L, it could inhibit 52. 5% light production. Triton X-100, acid, and alkali also had some effects on the reaction, while CTAB, SDS and TCA would inhibit the bioluminescent reaction seriously.

13C metabolic flux analysis(13CMFA)have been the research hotspots of metabolic engineering internationally due to its accuracy and applicability.It is vital that the measurement of 13C labelling pattern of proteinogenic amino acids for 13C metabolic flux analysis.To acquire 13C-labelling proteinogenic amino acids,Pseudomonas denitrifican which products Vitamin B12 was firstly fed with mimimal culture medium contained 20% U-13C and 80% natural glucose,after the culture reached a steady state,then about 20 mg biomass was hydrolyzed by 1 ml of 6 mol/L hydrochloric acid for 24h at 110℃.Then amino acids was separated,concentrated,evaporated in a vacuum,and derivatized with MBDSTFA,TBDMS-derivatized amino acids can be observed by GC-MS last we get 13C labelling pattern of fifteen aminio acids through mass spectrum.The experimental methods and sample preparation offers referential value for the development of 13C metabolic flux analysis in our courtry.

Optimization of the fermentation condition for human apolipoproteinA-I expression in recombinant Escherichia coli was investigated. The recombinant plasmid pBV220-ApoA-I was transformed respectively into different E.coli hosts such as JM109, BL21(DE3),DH5?, BMH7118,and TG1. The best host E.coli was DH5? in which the recombinant ApoA-I expression percentage was 21.2% corresponding to that in BL21(DE3) in flask shaker cultivation,while the ApoA-I expressed percentage in E.coli TG1 was 11%.Fed-batch cultivation was performed in FMG-5L fermentor,the optimum fermentation cultivation conditions were as following :optimum pH value was 7.0 in growth phase and 7.4 in the expression phase. The initial glucose concentration in batch phase was 3 g?L -1.The optimum C/N ratio was 2∶1.The recombinant ApoA-I reached about 40% of the total protein, and concentration of ApoA-I was 2.86 g?L -1.

The temperature effect on the recombinant protein production formation was investigated in present study. The culture temperature of growth phase is 30℃, and the culture temperature of induction phase was arranged according to three modes. Hign cell-density and high expression culture of E.coli to product recombinant human apolipoprotein A-I Milano by two temperature-shifted induction . Two temperature-shifted induction was carried out high density and high expression recombinant human ApoA-1 Milano. The recombinant protein ApoA-I Milano reached 4.8 g?L -1 with the final cell density of OD 600 150. And the two temperature-shifted induction avoided the acetic acid successfully to the influence of the high density and high expression. Two temperature-shifted induction was viable in high density culture and high expression of heterogenous protein in recombination E.coli.The sduty provides a basic work for production of recombinant ApoA-I Milano in scale.

Marine Actinobacteria are emerging as new resources for bioactive natural products with promise in novel drug discovery. In recent years, the richness and diversity of marine Actinobacteria from the South China Sea and their ability in producing bioactive products have been investigated. The objective of this work is to isolate and identify bioactive secondary metabolites from a marine actinobacterium SCSIO 1934 derived from sediments of South China Sea. The strain was identified as a Streptomyces spieces by analyzing its 16S rDNA sequence. Streptomyces sp. SCSIO 1934 was fermented under optimized conditions and seven bioactive secondary metabolites were isolated and purified by chromatographic methods including colum chromatography over silica gel and Sephadex LH-20. Their structures were elucidated as 17-O-demethylgeldanamycin (1), lebstatin (2), 17-O-demethyllebstatin (3), nigericin (4), nigericin sodium salt (5), abierixin (6), respectively, by detailed NMR spectroscopic data (1H, 13C, COSY, HSQC and HMBC). This work provided a new marine actinobacterium Streptomyces sp. SCSIO 1934, capable of producing diverse bioactive natural products.
Anti-Bacterial Agents ; chemistry ; China ; DNA, Ribosomal ; chemistry ; genetics ; Geologic Sediments ; microbiology ; Oceans and Seas ; RNA, Ribosomal, 16S ; genetics ; Streptomyces ; chemistry ; classification ; genetics ; isolation & purification