Preparation of functional polyhydroxyalkanoate microspheres and their antibacterial activity and osteogenic effect evaluation / 中国修复重建外科杂志

OBJECTIVE@#To construct polyhydroxyalkanoate (PHA) microspheres loaded with bone morphogenetic protein 2 (BMP-2) and human β-defensin 3 (HBD3), and evaluate the antibacterial activity of microspheres and the effect of promoting osteogenic differentiation, aiming to provide a new option of material for bone tissue engineering.@*METHODS@#The soybean lecithin (SL)-BMP-2 and SL-HBD3 were prepared by SL-mediated introduction of growth factors into polyesters technology, and the functional microsphere (f-PMS) containing BMP-2 and HBD3 were prepared by microfluidic technology, while pure microsphere (p-PMS) was prepared by the same method as the control. The morphology of microspheres was observed by scanning electron microscopy and the water absorption was detected; the release curves of BMP-2 and HBD3 in f-PMS were detected by ELISA kit. The antibacterial effect of microspheres in Staphylococcus aureus and Escherichia coli was tested with the LIVE/DEADTM BacLightTM bacterial staining kit; the biocompatibility of microspheres was tested using Transwell and cell counting kit 8 (CCK-8). The effect of microspheres on osteogenic differentiation was determined by collagen type Ⅰ (COL-1) immunofluorescence staining and alkaline phosphatase (ALP) concentration.@*RESULTS@#In this experiment, the f-PMS and p-PMS were successfully constructed. Morphological characteristics showed that p-PMS surface was rough and distributed with micropores of 1-3 μm, while f-PMS surface was smooth and existed white granular material. There was no significant difference in water absorption between the two groups (P>0.05). The release curves of BMP-2 and HBD3 in the f-PMS and p-PMS were basically the same, showing both early sudden release and late slow release. The antibacterial activity of f-PMS was significantly higher than that of p-PMS in the test that against Staphylococcus aureus and Escherichia coli (P<0.05), but there was no significant difference in biocompatibility between the two groups (P>0.05). The results of osteogenic differentiation of human BMSCs showed that the fluorescence intensity of osteogenic specific protein COL-1 of f-PMS was significantly higher than that in p-PMS, and the activity of ALP in f-PMS was also significantly higher than that in p-PMS (P<0.05).@*CONCLUSION@#The p-PHA have good antibacterial activity and biocompatibility, and can effectively promote the osteogenic differentiation of human BMSCs, which is expected to be applied to bone tissue engineering in the future.

The Value of Susceptibility-weighted Imaging in Evaluating the Histopathologic Grade of Cerebral Astrocytomas / 中国医学影像学杂志

Purpose:To investigate the value of susceptibility-weighted imaging(SWI)in evaluating the histopathologic grade of cerebral astrocytomas.Materials and Methods: 18 patients with histologically proven cerebral astrocytomas,including 7 diffuse astrocytomas,3 ana-plastic astrocytomas and 8 glioblastomas before treatment were involved in this study.The features on SWI were analyzed in 18 cerebral astrocytomas.Results: The veins in the tumors were not detected in 7 diffuse astrocytomas.Slight edema round tumors appeared in all the diffuse astrocytomas.Plenty veins in the tumors and severe edema round the tumors appeared in 3 anaplastic astrocytomas and 8 glioblastomas.The hemorrhagic foci were detected in 1 anaplastic astrocytomas and 6 glioblastomas.The edema round the tumors were moderate or severe in all the anaplastic astrocytomas or glioblastomas.Conclusions: Susceptibility-weighted imaging can provide the informations about blood supply,hemorrhagic focus and edema round the tumors.SWI is very useful for preoperative evaluation of the histopathologic grade of cerebral astrocytomas,especially for evaluation of high or low grade astrocytomas.