The effect of rotational alignment of the femoral components on the patellofemoral biomechanics in total knee arthroplasty / 中华外科杂志

<p><b>OBJECTIVE</b>To study the effect of rotational alignment of the femoral components on the patellofemoral biomechanics in total knee arthroplasty (TKA) demonstrated on autopsy specimens, as the guide for surgeons to choose the correct reference axis for rotational alignment of the femoral components and to reduce the patellofemoral joint complications.</p><p><b>METHODS</b>Select 9 frozen fresh human cadaver knees without gross deformities or instabilities and mount specimens on a patellofemoral joint testing jig connected to a Model 8501 Instron machine (Instron Corporation, Canton, MA). The study simulated the action of squatting from the standing position with the foot firmly planted. Standard TKA was performed in each specimen by the same senior surgeon using Nexgen LPS total knee system (Zimmer Corporation, Warsaw Indiana). Alter rotational alignment of the femoral components referenced to the transepicondylar axis and the Whiteside's line respectively. Measure biomechanics of the patellofemoral joints using Fuji prescale film at 30 degrees , 60 degrees , 90 degrees , 120 degrees of knee flexion respectively. The digital values were obtained by the handheld pressure measurement systems (FPD-305E, FPD-306E) and Autocad software.</p><p><b>RESULTS</b>The rotational alignment of the femoral components paralleled to the transepicondylar axis had the best results of the peak value of the patellofemoral contact pressure (P < 0.05). There were no statistically significant differences in patellofemoral contact area (P > 0.05). But the patellofemoral contact area had the close correlations to the angles of the knee flexion and the specimens.</p><p><b>CONCLUSIONS</b>Rotational alignment of the femoral components has a great influence on the patellofemoral contact pressure in total knee arthroplasty. It is reliable for surgeons to choose the transepicondylar axis as the reference axis to rotate femoral components.</p>

Expression and purification of heptad repeat region of the mumps virus F protein and analysis of characteristics / 生物工程学报

Two Heptad repeat motifs (HR1 and HR2) from paramyxoviruses F protein could form thermostable heterodimers containing high alpha-helix while virus infected host cell. Following that the viral membrane and the host cell membrane were juxtaposed, which leads to membrane fusion. Mumps virus (MuV) is a member of the genus Rubulavirus in the family of Paramyxoviridae. MuV could use similar infection mechanism as well as other paramyxoviruses. In this study the HR1 and HR2 regions of MuV F protein were predicted by a computer program and expressed in E. coli with the GST fusion expression system. The GST fusion or GST-removed proteins were purified with Gluthathion Sepharose 4B Column. GST pull-down experiment suggested the interaction of HR1 and HR2 peptides, and analysis of gel filtration showed two peptides could form multimer, which indicates that the HR regions of MuV F protein may play an important role in virus fusion.

VIABILITY,VIRULENCE AND STORAGE OF VACUUM-DRIED BEAUVERIA BASSIANA CONIDIA POWDER / 微生物学通报

The fresh conidia powder of Beauveria bassiana SGBB8702 produced with diphasic technology was dried using 36-h procedures of vacuum-freeze drying (VFD) or vacuum drying (VD). The VFD and VD procedures reduced water content of the fresh conidia powder from 58.56% to 3.97% and 4.26%, resulting in preparations containing 1.29, and 1.25?10 11 conidia/g. The VFD or VD conidia had the same viability (≥98%) as the fresh ones but germinated slightly more slowly than the fresh ones. The estimates of LC 50 s for the fresh, VFD, and VD conidia against Myzus persicae on day 7 after inoculation were 1.15, 5.89, and 2.95?10 4 conidia/ml, respectively. At the concentration of 10 6 conidia/ml, the LT 50 of the fresh conidia against M. persicae was estimated as 3.6 d, corresponding to 3.9 d and 4.4 d for the VFD and VD conidia, respectively. Due to much lower cost, the VD procedure was of greater potential for drying B. bassiana conidia in mass production though the VFD procedures resulted in slightly better quality of conidia powder. The viability and virulence of the VFD conidia were assessed periodically during 12-mon storage at 4℃ and 20℃, respectively. No viable conidia stored at 20℃ were detected 255 d after storage whereas those stored at 4℃ had a viability of 90.15% and an LT 50 of 4.7 d at the end of 12-mon storage. The results showed that storage of B. bassiana conidia powder at ambient temperature was unable to maintain shelf life at commercially acceptable level even though its water content was reduced to