BACKGROUND:The development of calcium phosphate bone cement is limited due to its poor mechanical properties and weak osteogenic ability.Silicate bioactive glass is highly favored due to its excellent biological activity and osteogenic ability.Simultaneously,fiber structures can enhance the mechanical strength of materials.OBJECTIVE:To investigate the mechanical properties,biocompatibility,and osteogenic effect of silicate bioactive glass fiber composite calcium phosphate bone cement.METHODS:Different mass percentages(0％,10％,and 20％)of silicate bioactive glass fiber were added to the solid phase of calcium phosphate bone cement,mixed with the liquid phase and cured for 48 hours to obtain silicate bioactive glass fiber composite calcium phosphate bone cement.The mechanical properties,setting time,and ion precipitation of the cement were characterized.The three groups of bone cement extracts were co-cultured with MC3T3-E1 cells.The cell compatibility of the materials was evaluated by CCK-8 assay,live/dead staining,and phalloidin staining.After osteogenic induction,the osteogenic induction ability of the materials was evaluated by alkaline phosphatase staining,alizarin red staining,RUNX2 immunofluorescence staining,and RT-PCR.RESULTS AND CONCLUSION:(1)With the increase of silicate bioactive glass fiber content,the compressive strength and flexural strength of bone cement increased,and the setting time was prolonged.When bone cement was immersed in simulated body fluid,the precipitation of silicon ions,calcium ions,and phosphorus ions could be detected.Moreover,with the increase of silicate bioactive glass fiber content,the mass concentration of silicon ions and phosphorus ions released by bone cement increased,and the mass concentration of calcium ions decreased.(2)Live/dead staining and phalloidin staining results exhibited that silicate bioactive glass fiber composite calcium phosphate bone cement had no toxic effect on MC3T3-E1 cells.CCK-8 assay results showed that silicate bioactive glass fiber composite calcium phosphate bone cement could promote the proliferation of MC3T3-E1 cells.(3)With the increase of silicate bioactive glass fiber content in bone cement,the alkaline phosphatase activity and extracellular calcium deposition of MC3T3-E1 cells increased,the expression of RUNX2 protein increased,and the expression of alkaline phosphatase,osteocalcin,osteopontin,and RUNX2 mRNA expression increased.(4)The results indicate that silicate bioactive glass fibers can enhance the mechanical properties and osteogenic induction ability of calcium phosphate bone cement,among which 20％silicate bioactive glass fibers have a more obvious effect.

BACKGROUND:The development of calcium phosphate bone cement is limited due to its poor mechanical properties and weak osteogenic ability.Silicate bioactive glass is highly favored due to its excellent biological activity and osteogenic ability.Simultaneously,fiber structures can enhance the mechanical strength of materials.OBJECTIVE:To investigate the mechanical properties,biocompatibility,and osteogenic effect of silicate bioactive glass fiber composite calcium phosphate bone cement.METHODS:Different mass percentages(0％,10％,and 20％)of silicate bioactive glass fiber were added to the solid phase of calcium phosphate bone cement,mixed with the liquid phase and cured for 48 hours to obtain silicate bioactive glass fiber composite calcium phosphate bone cement.The mechanical properties,setting time,and ion precipitation of the cement were characterized.The three groups of bone cement extracts were co-cultured with MC3T3-E1 cells.The cell compatibility of the materials was evaluated by CCK-8 assay,live/dead staining,and phalloidin staining.After osteogenic induction,the osteogenic induction ability of the materials was evaluated by alkaline phosphatase staining,alizarin red staining,RUNX2 immunofluorescence staining,and RT-PCR.RESULTS AND CONCLUSION:(1)With the increase of silicate bioactive glass fiber content,the compressive strength and flexural strength of bone cement increased,and the setting time was prolonged.When bone cement was immersed in simulated body fluid,the precipitation of silicon ions,calcium ions,and phosphorus ions could be detected.Moreover,with the increase of silicate bioactive glass fiber content,the mass concentration of silicon ions and phosphorus ions released by bone cement increased,and the mass concentration of calcium ions decreased.(2)Live/dead staining and phalloidin staining results exhibited that silicate bioactive glass fiber composite calcium phosphate bone cement had no toxic effect on MC3T3-E1 cells.CCK-8 assay results showed that silicate bioactive glass fiber composite calcium phosphate bone cement could promote the proliferation of MC3T3-E1 cells.(3)With the increase of silicate bioactive glass fiber content in bone cement,the alkaline phosphatase activity and extracellular calcium deposition of MC3T3-E1 cells increased,the expression of RUNX2 protein increased,and the expression of alkaline phosphatase,osteocalcin,osteopontin,and RUNX2 mRNA expression increased.(4)The results indicate that silicate bioactive glass fibers can enhance the mechanical properties and osteogenic induction ability of calcium phosphate bone cement,among which 20％silicate bioactive glass fibers have a more obvious effect.

Objective:To investigate effects of bone-resorptive lesion on stress distribution of femoral head and on progression in patients with osteonecrosis of the femoral head (ONFH).Methods:From April 2014 to September 2018, a total of 155 femoral heads from 94 patients diagnosed with ARCO stage II and III ONFH were retrospectively reviewed, including 77 males and 17 females with aged 39.90±10.45 years old (ranged from 18-64 years). The hips were divided into two groups according to whether there were bone-resorptive lesions. Further, we compared whether there was statistical difference between the two groups in staging. Then, a case of ARCO II hip joint without bone-resorptive lesion was selected from the included patients. Six femoral head with different diameters of spherical bone-resorptive lesion of 5 mm, 7 mm, 10 mm, 14 mm, 18 mm, and 23 mm were simulated. The influence of bone-resorptive lesion on the stress distribution of necrotic area and a spherical shell extending 1 mm radially around the bone-resorptive lesion was investigated by finite element method in slow walking conditions.Results:Of the 155 ONFH hips, 67 hips are complicated by bone-resorptive lesions, of which 17 were ARCO II, 50 were ARCO III. A total of 88 hips did not contain bone-resorptive lesions, of which 58 were ARCO II, ARCO III 30 cases. The proportion of ARCO stage II in the group with bone-resorptive lesions was significantly higher than that in the group without bone-resorptive lesions (χ 2=25.03, P=0.000). The finite element stress distribution cloud diagram showed that there was a stress concentration area around the bone-resorptive lesions. The maximum von Mises stress around bone-resorptive lesions in the models that contained a synthetic bone-resorptive lesions were significantly higher than those reported in the matched, non-synthetic bone-resorptive lesions finite element models ( t=3.139, P=0.026). The values for maximum von Mises stress around bone-resorptive lesions were 6.94±1.78 MPa and 5.01±0.35 MPa for the group with synthetic bone-resorptive lesions and the group non-synthetic bone-resorptive lesions, respectively. There was a positive correlation between the diameter of bone-resorptive lesions and the maximum and mean von Mises stress of necrotic areas as well as the maximum von Mises stress around bone-resorptive lesions. Conclusion:Bone-resorptive lesions can increase the maximum stress and average stress in the necrotic area. The larger the bone-resorptive lesion, the more the stress increases. There is a stress concentration area around the bone-resorptive lesions, which may accelerate the collapse of the femoral head.

Objective To study the relationship between serum HBV DNA level and apoptosis of peripheral blood mononuclear cells (PBMC) , and the relationship between serum HBV DNA level and the activity of caspase-8 in the patients with chronic hepatitis B (CHB). Method 30 CHB patients were selected as experimental group, and it was divided into three subgroups according to the serum HBV DNA level, subgroup A (high serum HBVDNA), subgroup B (medium serum HBVDNA), and subgroup C (low serum HBVDNA). 10 healthy adults were random selected as control group. PBMC were isolated from two groups by separating medium of lymphocytic cell and culturing it with phytohemagglutinin (PHA) in vitro for 72 hours. The PBMC was stained with PI and the apoptosis was assayed with flow cytometry. At the same time, the aetivity of caspase-8 of PBMC was assayed by color matching. Results The apoptosis rate of PBMC of experimental group ( 26. 88 ± 7.37 ) % were higher than that of the control group ( 14. 95 ±2. 53)% ( P <0. 01 ). In the experimental group, the apoptosis rate of PBMC of subgroups A, B and C showed decreasing order (34. 75 ± 4. 59)%, (25.63 ± 3.55 )%, ( 18. 91 ± 3. 81 )%. The activity of caspase-8 of experimental group 2. 99 ±0. 82 were higher than that of the control group 1.43 ±0. 91 ( P <0. 01 ). The activity of caspase-8 of subgroup A, B and C showed the same decreasing order: 3. 87 ±0. 35,2. 95 ± 0. 36, 1.95 ± 0. 29. There was a positive correlation between the apoptosis level of PBMC and the activity of caspase-8 in experimen tal group ( r = 0. 610, P < 0. 01 ). Conclusion AICD of PBMC was found in patients with CHB. The activity of caspase-8 increased in that process, and it may participate in the transduction of apoptosis signal. Serum HBV DNA level was related with the apoptosis rate of PBMC and the activity of caspase-8, and it may be one of the reasons of apoptosis in PBMC.

OBJECTIVE To investigate the prevalence of ?-lactamases in nosocomial infections of Enterobacter cloacae,study the different genotyping of ?-lactamases,and analyze its independence in drug resistance. METHODS AmpC ?-lactamases and ESBLs were detected by three-dimensional extract tests.PCR was used to determine the genotype of ?-lactamases and their resistance to 13 kinds of antibiotics was detected by Kirby-Bauer method. RESULTS The sensitivity test showed that they were resistant to the most antibiotics.Among the 80 ESBLs strains,29 strains carried ESBLs gene,3 strains carried two different gene.Such as:TEM existed in 6,SHV-Ⅰ existed in 2,CTX-M-2 existed in 5,CTX-M-3 existed in 8 and CTX-M-9 existed in 11 strains.Twenty-six strains carried ampC.The resistant rate of SSBLs-producing E.cloacae to 12 antibiotics except merapenem was 66.7-100.0%.SSBLs strains of E.cloacae were higher than AmpC ?-lactamases in resistance to levofloxacin,cefepime,aztronem and trimethoprim sulpfamethoxazole with significant difference(P