Objective To analyze the effect of mesporous calcium silicate (m-CS)/calcium sulfate cement (CSC),m-CSC for short,in bone defect repair.Methods Setting time and compressive strength of the m-CSC (15 m-CSC as group Ⅰ and 30 m-CSC as group Ⅱ) were tested.CSC was used as the control.Cement samples were immersed in Tris-HCl solution,andin vitro degradation of the m-CSC was measured.Cell morphology and cell proliferation as well as differentiation on the samples were assessed.The cements were implanted into the traumatic femoral defects in rabbits,and the in vivo degradability and osteogenesis of the cements were investigated by histological evaluation after implantation for 4,8 and 12 weeks.Results Addition of m-CS into CSC prolonged the setting time (7.8 min in group Ⅰ and 10.5 min in group Ⅱ),obviously longer than 3.7 min in control group and did not have obvious effect on compressive strength of the cements.Weight loss of m-CSC solution was obviously lower (61.8 wt％ in group Ⅰ and50.3 wt％ in group Ⅱ),compared to70.4 wt％ in control group,pH value in group Ⅱ decreased from 7.40 to 7.26,while decreased from 7.40 to 6.86 in control group,m-CSC could promote cell proliferation and differentiation compared to CSC.At postoperative 12 weeks,histological sections showed massive new bony tissue (55.2％) in group Ⅱ,obviously higher than 25.6％ in control group.Conclusion m-CSC exhibits good biocompatibility,degradability and osteogenesis,and can promote bone regeneration in bone defect repair.

Objective To investigate the pathogen distribution and risk factors of pulmonary infection after acute cervical spinal cord injury (ACSCI) in an attempt to offer reference for early antiinfection therapy.Methods The study comprised 223 cases who were admitted from October 2011 to October 2014.There were 149 males and 74 females,at (43.3 ± 13.5) years of age.Species of pathogens identified were gram-positive,gram-negative and mixed.Effects of age,gender,injury types and tracheotomy on pathogen distribution were analyzed.Results Gram-negative infection was found in 114 cases (51.1％),with tracheotomy accounting for 7.0％ of the cases and death accounting for 1.8％ of the cases,and the main causative pathogens were Klebsiella pneumonia,Escherichia coli,Pseudomonas aeruginosa and Acinetobacter baumannii.Gram-positive infection was found in 41 cases (18.4％),with tracheotomy accounting for 12.2％ of the cases and death accounting for 7.3％ of the cases,and the main causative pathogens were Staphylococcus aureus and Streptococcus pneumonia.Mixed infection was found in 68 cases (30.5％),with tracheotomy accounting for 22.1％ of the cases and death accounting for 13.2％ of the cases.Gender had no significant correlation with pathogen distribution.For the cases of complete spinal cord injury and tracheotomy,the ratio of mixed infection increased significantly (P ＜ 0.05).For the cases younger than 30 years,the pathogens were mainly gram-positive bacteria (P ＜ 0.05).Conclusions Main pathogens of pulmonary infection after ACSCI are gram-negative bacteria.The cases younger than 30 years are associated with higher risk of grampositive infection,while the cases with complete injury or tracheotomy are associated with higher risk of mixed infection.