Expression of H5N1 avian influenza virus haemagglutinin protein in pichia pastoris by high-density cell fermentation / 生物工程学报

We produced high pathogenic avian influenza H5N1 haemagglutinin protein HA1 in recombinant Pichia pastoris in a 10 L fermentor, to establish a high-density cell fermentation method. We studied the effects of different factors such as culture temperature, induced temperature, methanol feeding methods, trace elements on the growth of Pichia pastoris, the yield and the biologic activity of recombinant HA1 protein. The culture temperature in pre-induced and induced stage were optimized at 25 degrees C to adapt cell growth and recombinant protein expression, and induced temperature at 25 degrees C also resulted in higher biologic activity of rHA1 than at 30 degrees C. The binding activity of rHA1 against a wide-spectrum neutralizing antibody was susceptible to the presence of any trace elements, although trace elements would essentially benefit for the cell fermentation. As a conclusion, the expression level of rHA1 produced with optimized fermentation process reached 120 mg/L, which was 10.5 times higher than the one produced in regular shaking flask. The resultant high-density cell fermentation can likely produce rHA1 of H5N1 in large scale.

Quantitive analysis of regional left ventricular systolic function before and after PTCA by quantitative tissue velocity imaging / 中国基层医药

Objective To analyze regional left ventricular systolic function before and after percutaneous translumial coronary angioplasty(PTCA),quantitative tissue velocity imaging(QTVI)was used tO detect wall motion of left ventricule.Methods 20 patients with isolated left anterior descending coronary artery(LAD)stenosis(≥70%)and 16 normal control subjects were included in this study.QTVI was performed one day before PTCA+stent,a week and a month after successful PTCA+stent.Peak systolic myocardial velocity(Vs)were measured with QTVI at different wall segments(basal and medial segments).Results Before PTCA+stent,Vs of all segments assigned by LAD were significantly lower than those of corresponding segments in normal subjects(P＜0.01).After PTCA+stent,the above segments showed a significant improvement of Vs in a week and a month(P＜0.01).Conclusion QTVI can quantitively detect changes of myocardiac motion and real-time quantify regional left ventricular systolic function before and after PTCA.