BACKGROUND: High molecular materials have been proved to enhance the mechanical properties of calcium phosphate bone cement, as well as attenuate the injectability of composite materials. It thereby influences the clinical application of composite materials.OBJECTIVE: To observe the compressive strength and injectability of silk fihroin compound calcium phosphate bone cement, to evaluate the effect of silk fibroin on calcium phosphate, and to investigate the feasibility of applying silk fibroin as an injectable hone substitute to repair hone defects.DESIGN, TIME AND SETTING: Controlled study was performed in the central laboratory of Analysis and Testing Center, Soochow University from September to December in 2007.MATERIALS: Calcium phosphate cement was purchased from Shanghai Rebone Biomaterials Co., Ltd; silk fibroin was offered by Institute of Material & Engineering, Soochow University.METHODS: Six groups were set with different mass fractions (0.5%, 1%, 1.5%, 2%, 2.5%, 3%) of silk fibroin, which were mixed with bone cement at a certain liquid/solid ratio of 0.4 mL/g to prepare the calcium phosphate composite. The calcium phosphate cement without silk fibroin was served as control group.MAIN OUTCOME MEASURES: The compressive strength and injectability were determined. The characteristic microstructure was observed using scanning electron microscope.RESULTS: The compressive strength increased firstly and then decreased with the addition of silk fibroin. The compressive strength of the experimental groups was remarkably higher than the control group when the silk fibroin content was 1%-2.5% (P<0.05). The injectability of the paste diminished with the addition of silk fibroin, which was statistically different when the silk fibroin content was 1.5%-3% (P<0.05). Scanning electron microscope result revealed that the silk fihroin penetrated throughout calcium phosphate crystals, which were tightly connected.CONCLUSION: Silk fibroin can improve the compressive strength of silk fibroin/calcium phosphate cement composites without significant influence of manipulation, and can widen the application field of calcium phosphate bone substitute.

Objective To explore the risk factors of antidepressant treatment emergent suicidal ideas or attempted suicide among patients with bipolar depression. Methods Out of 623 patients with bipolar disorder visiting between June 2006 and June 2009,68 who was initially diagnosed as unipolar disorder and treated with antidepressants were retrospectively surveyed. Suicide and activation symptoms during the process of antidepressant treatment were estimated based on the cases record and semi-structural interviews. Unconditional bivariate logistic regression was conducted to analyze the potential risk factors. Results Of 68 patients,7 ( 10. 3% ) experienced antidepressant treatment emergent suicidal ideas and 4 ( 5.9% ) attempted suicide after 2 to 63 ( 17.45 ± 5.90 )days following the treatment. The antidepressant treatment emergent suicidal ideas or attempted suicide were related to the suicidal level before treatment (P= 0. 012, OR = 2. 072 ) and the combined use of benzodiazepine (P =0. 043, OR = 0.236). Clinical subtypes, gender, age, symptoms feature, types of antidepressant and antidepressanttreatment emergent activation symptoms had little impact on the antidepressant treatment emergent suicidal ideas orattempted suicide (P ＞ 0.05 ). Conclusion The antidepressant treatment emergent suicidal ideas or attempted suicide among patients with bipolar depression are positively related to the suicidal level before treatment while negatively associated with the combined use of benzodiazepine.

Objective To evaluate the osteogenic characteristics of an injectable silk fibroin (SF) enhanced calcium phosphate cement (CPC) composite loaded with recombinant human bone morphogenetic protein-2 (rhBMP-2) on lumbar interbody fusion in sheep. Methods Twenty-four mature sheep were randomly divided into two groups. Each sheep underwent L1.2, L3.4 and L5.6 lumber interbody fusion, and the three disc spaces were randomly implanted with three of the following materials: SF/CPC, CPC/rhBMP-2, SF/CPC/rhBMP2 and autogenous iliac crest bone. One group was killed at 6 months and the other at 12 months. The fusion segments were observed and analyzed by manual palpation, CT scan, undestructive biomechanical testing, undecalcified histology, and histomorphology. Results The fusion rates of SF/CPC, CPC/rhBMP-2, SF/CPC/rhBMP-2 and autogenous bone assessed by manual palpation were 0, 33.33%, 55.56% and 77.78% respectively at 6 months. At 12 months, the fusion rates improved to 11.11%, 44.44%, 77.78% and 77.78%, respectively.The biomechanical results showed that fusion stiffness was significantly greater in autograft compared with SF/CPC/rhBMP-2, CPC/rhBMP-2, and SF/CPC in 4 degrees of freedom (flexion, extension, right bending, and left bending) at 6 months. The SF/CPC/rhBMP-2 composite showed similar stiffness as autograft, which was significantly greater than CPC/rhBMP-2 and SF/CPC at 12 nonths. Both CPC/rhBMP-2 and SF/CPC/rhBMP-2 showed significantly greater stiffness at 12 months compared with that of at 6 months. The results showed that bone volume was significantly greater in autograft compared with SF/CPC/rhBMP-2, CPC/rhBMP-2, and SF/CPC at 6 months. There was significant difference among ceramic residue among SF/CPC, CPC/rhBMP-2 and SF/CPC/rhBMP-2, with SF/CPC the greatest and SF/CPC/thBMP-2 the least. At 12 months, the bone volume of SF/CPC/rhBMP-2 composite was comparable with autograft, and greater than that of CPC/rhBMP-2 and SF/CPC. The bone volume of SF/CPC, CPC/rhBMP-2 and SF/CPC/rhBMP-2 was significantly greater at 12 months than that of at 6 months. The ceramic residue of SF/CPC, CPC/rhBMP-2 and SF/CPC/rhBMP-2 were significantly decreased. Conclusion The SF/CPC/rhBMP-2 composite had excellent osteoconduction and osteoinduction, and balanced degradation and osteogenesis, which may be a kind of ideal bone grafts in spinal fusion.

Objective:To analyze the clinical efficacy of treatment of cement dislodgement after vertebral augmentation for osteoporotic vertebral fractures.Methods:A retrospective study was conducted to analyze the data of 13 patients who had been treated at Department of Orthopaedics, The First Affiliated Hospital of Soochow University for cement dislodgement after vertebral augmentation for osteoporotic vertebral fractures from July 2013 to July 2022. There were 4 males and 9 females, with an average age of (76.5±8.6) years and a T value of bone mineral density of -3.3±0.6. By the CT and MRI features of cement dislodgement, their conditions fell in 4 types: cement loosening in situ (4 cases), anterior cement moving (6 cases), anterior cement moving with posterior bone mass moving (2 cases), and posterior cement moving (1 case). They were treated by percutaneous vertebroplasty (3 cases), pedicle screw fixation combined with bone graft fusion and decompression (7 cases), and conservative therapy (3 cases). The curative effects for surgical patients were evaluated by comparing their visual analogue scale (VAS), Oswestry dysfunction index (ODI) and cobb angle of kyphosis at preoperation, 1 week and 1 month postoperation, and the last follow-up, and Frankel grading for nerve injury as well. The curative effects for patients undergoing conservative treatment were evaluated by observing their symptoms.Results:This cohort was followed up for 7 (5, 12) months after treatment. The VAS scores [5.0 (4.0, 5.0) points, 3.0 (2.0, 3.0) points, and 3.0 (2.0, 3.0) points] in the 10 surgical patients at 1 week and 1 month postoperation and the last follow-up were significantly improved compared with the preoperative value [8.5 (8.0, 9.0) points] ( P<0.05); the VAS scores at 1 month postoperation and the last follow-up were also significantly improved compared with that at 1 week postoperation ( P < 0.05), but there was no significant difference between the last follow-up and 1 month postoperation ( P > 0.05). The ODIs (50.6%±4.2%, 37.8%±4.5%, and 29.3%±5.6%) in the 10 surgical patients at 1 week and 1 month postoperation and the last follow-up were significantly improved compared with the preoperative value (93.2%±3.6%), showing significant differences in pairwise comparisons ( P<0.05). The cobb angles [10.0 (9.0, 11.0)°, 9.0 (9.0, 11.0)°, and 10.0 (9.0, 12.0)°] in the 10 surgical patients at 1 week and 1 month postoperation and the last follow-up were significantly improved compared with the preoperative value [12.5 (11.0, 14.0)°] ( P<0.05) , but there was no statistically significant difference between the time points after operation ( P>0.05). The Frankel grading was significantly improved in the 6 patients with nerve injury after operation. Of the 3 patients undergoing conservative treatment, the symptoms were cured in one, showed no change during follow-up in one, and aggravated in one. Conclusion:Surgical treatment can significantly relieve pain, improve spinal dysfunction and repair nerve injury in patients with bone cement dislodgement after vertebral augmentation.