Objective To study in vitro sustained release behaviour of the recombinant human bone morphogenetic protein 2(rhBMP-2) from the sample which porous calcium phosphate cement (PCPC) was combined with rhBMP-2, and to evaluate the effect of PCPC/rhBMP-2 composite on repairing bone defect in the animalstudy.Methods rhBMP-2 was absorbed into PCPC by vacuum-adsorption and freeze-dried at -40℃, the PCPC/rhBMP-2 enwrapped with chitosan as the experimental group, the pure PCPC/rhBMP-2 as the control group, then the sustained release ofrhBMP-2 from PCPC was determined in simulated body fluid (SBF) by UV-VIS spectrophotometer. At same time, the PCPC/rhBMP-2 composites with chitosan were implanted into the (4.2 mm×5.0 mm femora defects of rabbits, which were considered as the experimental group, whereas in the control group only PCPC was implanted. The effect of repairingbone defect was evaluated in the 4th and 8th week postoperatively by radiograph and histomorphology.Results The PCPC have a high absorption efficiency to rhBMP-2, and the release of rhBMP-2 was sustained release system. The release of rhBMP-2 from PCPC in the experimental group (99% after 350 hours) was slowerthan that in the control group (100% after 150 hours). In the experimental group, the radiological and histomorphological evaluations showed that theinterfaces between the materials and host bones became blurred both at 4th and 8th week. The implanted materials were partially absorbed, and the implanted areas exhibited the formation of new bone. In the control group, a little amount of new bones was observed. Conclusion The PCPC shows great clinical potential as a carrier for rhBMP-2. The PCPC/rhBMP-2 composite possesses much potentialities of osteoinductivity and the ability of repairing bone defect, so it can be used as a novel bone substitute clinically.
ObjectiveTo systematically review the detection rate of sub-health status of Chinese college students. MethodsThe CNKI, WanFang Data, CBM, VIP, PubMed, EMbase and Web of Science databases were searched to collect cross-sectional studies on the detection rate of sub-health among Chinese college students from inception to February 1, 2023. Two researchers independently screened the literature, extracted data and evaluated the risk of bias of the included studies. Meta-analysis was performed using Stata 17.0 software. At the same time, GIS technology was used to analyze the spatial distribution of the detection rate of sub-health status of college students in China. ResultsA total of 44 articles were included, with a total sample size of 63 435 cases, including 29 255 cases of sub-health status. The results of meta-analysis showed that the detection rate of sub-health status of Chinese college students was 51.2% (95%CI 44.1 to 58.4). The temporal distribution showed a gradual decrease in the detection rate of sub-health states among college students between 2016 and 2020, with a rebound after 2020. The detection rates of sub-health states among college students in different regions and survey instruments varied significantly, with 74.1%, 61.8%, 58.4%, 56.1%, 47.0%, 42.3% and 21.6% in Southwest, Northeast, South, North, Central, East and Northwest China, respectively. The detection rates of sub-health states among college students in Jilin, Sichuan and Hebei provinces were the top 3, and Shanxi province had the lowest detection rate. ConclusionThe detection rate of university sub-health status in China is high, and the detection rate decreased significantly from 2016 to 2020, with a rebound trend in recent years, and there are differences in the detection rate of university sub-health status in different regions and survey instruments. Due to the limitation of the quality and quantity of the included studies, the above findings need to be verified by more high-quality literature.