Spinal cord injury (SCI) is a complex pathological process. Based on the encouraging results of preclinical experiments, some stem cell therapies have been translated into clinical practice. Mesenchymal stem cells (MSCs) have become one of the most important seed cells in the treatment of SCI due to their abundant sources, strong proliferation ability and low immunogenicity. However, the survival rate of MSCs transplanted to spinal cord injury is rather low, which hinders its further clinical application. In recent years, hydrogel materials have been widely used in tissue engineering because of their good biocompatibility and biodegradability. The treatment strategy of hydrogel combined with MSCs has made some progress in SCI repair. This review discusses the significance and the existing problems of MSCs in the repair of SCI. It also describes the research progress of hydrogel combined with MSCs in repairing SCI, and prospects its application in clinical research, aiming at providing reference and new ideas for future SCI treatment.
Objective To analyze the results of intra-aortic balloon pump (IABP) support in patients receiving coronary artery bypass graft (CABG) and the risk factors of postoperative death. Methods The clinical data of 334 patients undergoing CABG procedure and receiving IABP support in Fuwai Hospital from January 1999 to April 2012 were retrospectively analyzed. According to the IABP insertion timing, the patients were divided into three groups: pre-, intra- and postoperative IABP groups. There were 45 males and 11 females aged 60.5±10.7 years in the preoperative IABP group, 84 males and 23 females aged 61.1±8.4 years in the intraoperative IABP group and 119 males and 52 females aged 61.4±8.5 years in the postoperative IABP group.Outcomes of the three groups were compared, including mortality, major complications, ICU stay, hospital stay and total costs. Multivariable logistic regression analysis was used to predict independent risk factors for postoperative in-hospital death. Results The total in-hospital mortality was 16.8% (56/334). Mortality was significantly different among the pre-, intra- and postoperative IABP groups (3.6% vs.23.4%vs. 17.0%, P=0.006). There was no significant difference in complications among the three groups (P=0.960). Multivariable logistic regression analysis indicated that independent risk factors for postoperative mortality included old age (OR=1.05, P=0.040), female (OR=3.34, P<0.001) and increasing left ventricular end-diastolic diameter (LVEDD,OR=1.06, P=0.040). Preoperative IABP support was protective factor (OR=0.10, P=0.050). Conclusion The results of IABP support in CABG patients are satisfactory, and patients with preoperative IABP have a lower mortality. Risk factors for postoperative death include old age, female and increasing LVEDD. Preoperative IABP support is a protective factor.
Glaucoma is the leading cause of irreversible blindness, but its early symptoms are not obvious and are easily overlooked, so early screening for glaucoma is particularly important. The cup to disc ratio is an important indicator for clinical glaucoma screening, and accurate segmentation of the optic cup and disc is the key to calculating the cup to disc ratio. In this paper, a full convolutional neural network with residual multi-scale convolution module was proposed for the optic cup and disc segmentation. First, the fundus image was contrast enhanced and polar transformation was introduced. Subsequently, W-Net was used as the backbone network, which replaced the standard convolution unit with the residual multi-scale full convolution module, the input port was added to the image pyramid to construct the multi-scale input, and the side output layer was used as the early classifier to generate the local prediction output. Finally, a new multi-tag loss function was proposed to guide network segmentation. The mean intersection over union of the optic cup and disc segmentation in the REFUGE dataset was 0.904 0 and 0.955 3 respectively, and the overlapping error was 0.178 0 and 0.066 5 respectively. The results show that this method not only realizes the joint segmentation of cup and disc, but also improves the segmentation accuracy effectively, which could be helpful for the promotion of large-scale early glaucoma screening.
Objective To investigate the effect of tetramethylpyrazine (TMP) with a certain concentration added to vitrification solution on peripheral nerve allografts regeneration. Methods Forty-eight healthy clean SD male rats were selected as donors, and 96 healthy clean Wistar male rats as recipients, all rats being 3 months old and weighing 200-250 g. The sciatic nerves segments of 15 mm were removed from the donors, then randomly divided into 4 groups according to vitrificationsolution containing TMP. No TMP was used in group A as the control group; 100 mg/L, 200 mg/L and 400 mg/L TMP were used in group B, group C and group D, respectively. Then them were cryo-preserved at — 196 ℃ for 3 weeks. Nerve defect of 10 mm in length was made in the sciatic nerves of recipients. After rewarming, the allografts were transplanted to the corresponding rats. The gross appearance, the morphological and electrophysiological changes, the image analysis of axons and motor end-plate were detected at 4, 8, 12 and 16 weeks. Results All rates survived to the end of the experiment. The adhesion and edema of allografts in group A and group B were obvious 4 weeks after operation; then adhesion and edema was obvious in group A and were improved in the other groups 8 weeks after operation. Adhesion was observed in groups A and B; no adhesion was observed in groups C and D at 12 weeks. The number of regeneration nerve, the latent, the ampl itude, the nerve conduction velocity, the medullary sheath/μm2, the medullary sheath density/μm2 and the image analysis of axons and motor end-plate in groups A and B were significantly lower than those in groups C and D (P lt; 0.01); and there were no significant differences between groups C and D (P gt; 0.05). The observation of transmission electron microscope showed that medullated nerve fibers and myel in sheath of groups C and D were thicker than groups A and B, layers of groups C and D were clear. Conclusion The vitrification solution with 200 mg/L tetramethylpyrazine has protective effect on regeneration of peripheral nerve allografts．