OBJECTIVETo develop nano-hydroxyapatite/collagen (NHAC) composite and test its ability in bone repairing.

METHODSNHAC composite was developed by biomimetic method.

RESULTSThe composite showed some features of natural bone in both composition and microstructure. The minerals could contribute to 50% by weight of the composites in sheet form. The inorganic phase in the composite was carbonate-substituted hydroxyapatite (HA) with low crystallinity and nanometer size. HA precipitates were uniformly distributed on the type I collagen matrix without preferential orientation. The composite exhibited an isotropic mechanical behavior. However, the resistance of the composite to localized pressure could reach the lower limit of that of femur compacta. The tissue response to the NHAC composite implanted in marrow cavity was investigated. Knoop micro-hardness test was performed to compare the mechanical behavior of the composite and bone. At the interface of the implant and marrow tissue, solution-mediated dissolution and macrophage-mediated resorption led to the degradation of the composite, followed by interfacial bone formation by osteoblasts. The process of implant degradation and bone substitution was reminiscent of bone remodeling.

CONCLUSIONThe composite can be incorporated into bone metabolism instead of being a permanent implant.

Animals ; Bone Regeneration ; Bone Remodeling ; Bone Substitutes ; Carbon ; Collagen ; Durapatite ; Femur ; injuries ; surgery ; Implants, Experimental ; Nanotechnology ; Rabbits

OBJECTIVETo construct a mineralized collagen based composite by biomimetic synthesis for bone tissue engineering.

METHODSUsing the molecular collagen as the template, the calcium phosphate is deposited on it to produce a mineralized collagen based composite, then is combined with minute amount of poly lactic acid (PLA), the three-dimensional scaffold composite is prepared by liquid phase separation. Using osteoblast culture technique, the biocompatibility of this biomaterial in vitro is detected by x-ray diffraction, SEM, TEM, fluoroscopy and CLSM.

RESULTSBoth degree and the size of crystals in the composite are low, which are similar to that of nature bone. It possesses porous structure and the porosity of the composite is high. The typical fibrillar microstructure is self-assembled of the collagen and the nano-crystal hydroxyapatite (HA) in the composite, moreover, the x-ray diffraction graphic of HA crystal shows the [002]-oriented.

CONCLUSIONSThe biomimetic three-dimensional composite can serve as one of the optimal scaffold material for bone tissue engineering both on structure and on property.

Animals ; Animals, Newborn ; Biocompatible Materials ; chemistry ; Bone Substitutes ; Calcium Phosphates ; Cells, Cultured ; Collagen ; chemistry ; Lactic Acid ; chemistry ; Nanotechnology ; Osseointegration ; Osteoblasts ; cytology ; Polyesters ; Polymers ; chemistry ; Rats ; Rats, Wistar ; Tissue Engineering

OBJECTIVETo investigate effects of hydroxyapatite (HA) and porous tricalcium phosphate/hydroxyapatite (TCP/HA)-coating titanium on the adhesion behavior of human gingival fibroblasts (HGFs).

METHODSCoatings of HA and duplex phases TCP/HA on titanium (Ti) were formed by ion beam assisted deposition (IBAD) method. Attachment, spreading, extracellular matrix (ECM) production, and focal adhesion plaque formation of HGFs were investigated on commercially pure (CP) titanium, HA-coated CP titanium and porous TCP/HA-coated CP titanium. After incubation of HGFs on these substrates, the number of attached cell, the area of cell spreading, immunostained ECM including fibronectin (FN) and type I collage, and vinculin (presenting the formation of focal adhesion plaque) were quantified by morphometric analysis using immunofluorescence microscope.

RESULTSTCP/HA and HA coatings exhibited that the attached cell number and cell spreading area were greater than those of CP titanium (P < 0.05), and the formation of focal adhesion plaque was earlier than that of uncoated substrate (P < 0.05). The number of attached cell and the formation of type I collagen on TCP/HA were more than those on Ti and HA. After 24-hour incubation on TCP/HA surface, the number of attached cell was 198.1 +/- 27.7 and the fluorescent intensity of type I collagen was 154.10 +/- 31.56. While under the same condition, the corresponding numbers for the CP titanium were 125.1 +/- 29.9 and 132.63 +/- 35.26. The differences between the two groups were significant (P < 0.05).

CONCLUSIONSIn this study, the porous TCP/HA coating significantly facilitated the adherence of human gingival fibroblasts to Ti surface and could improve the biocompatibility of titanium.

Calcium Phosphates ; pharmacology ; Cell Adhesion ; drug effects ; Cells, Cultured ; Coated Materials, Biocompatible ; chemistry ; Durapatite ; pharmacology ; Fibroblasts ; cytology ; drug effects ; Gingiva ; cytology ; Humans ; Materials Testing ; Titanium ; chemistry

Objective:To investigate the effects of 40 Hz and 70 Hz frequency flash stimulation on the ability of learning memory and autonomous exploratory in young rats.Methods:Twenty-seven SPF grade male SD rats aged 19-21 days were divided into control group (Ctr group), 40 Hz group and 70 Hz group with 9 in each group according to the random number table.The rats in Ctr group were not given flash stimulation, while rats in the 40 Hz and 70 Hz group were received 40 Hz, 70 Hz flash stimulation (1.5 h/d for 39 days), respectively.The Morris water maze experiment was used to assess the learning and memory ability of rats, and the open field experiment was used to evaluate the ability of autonomous exploratory of rats.Nissl staining was used to assess the morphology of Nissl bodies in the hippocampus CA1 region of the rats.The local field potentials (LFPs) collected from the primary visual cortex (V1 area) region by electrophysiological experiments was used to verify the synchronization of flash evoked neural oscillations.SPSS 23.0 software was used for statistical analysis.The repeated measures ANOVA and one-way ANOVA were used to analyze normal distribution measurement data, and LSD and Tamhane tests were used for further pairwise comparison.The Kruskal-Wallis test was used for non-normal distribution measurement data.Results:(1) The flash stimulation of 40 Hz and 70 Hz both can effectively caused synchronization of neural oscillations in the primary visual cortex of healthy young rats.(2) The results of repeated measures ANOVA analysis showed that there was no interaction effect of grouping and time in the escape latency of young rats in the Morris water maze positioning navigation phase( F=1.326, P>0.05 ). The escape latency had time main effect ( F=40.025, P<0.05), but no grouping main effect ( F=2.039, P>0.05). With the increase of learning days, the escape latency of young rats in each group decreased significantly.There was no interaction effect of grouping and time in the total distance of young rats ( F=2.029, P>0.079). It had time main effect ( F=32.052, P<0.05), but not grouping main effect ( F=2.390, P>0.05) on total distance.With the increase of learning days, the total distance of young rats in each group significantly shortened.On the 6th day of the Morris water maze experiment, there was no statistically significant difference among groups in terms of time in the target quadrant and the number of crossing platforms ( F=2.511, 0.802, both P>0.05). The results of the open field experiment showed that the total distance traveled in the center of young rats in each group was statistically significant ( H=8.935, P<0.05), the total distance traveled in the center in the 70 Hz group (3.80 (2.25, 6.93) m)was significantly longer than that in the 40 Hz group (0.80 (0.72, 1.46) m), P<0.05). The percentage of time spent in the center was statistically significant in the three groups ( H=11.050, P<0.05). Young rats in the 70 Hz group spent significantly higher percentage of time in the center(3.20(2.43, 8.30)) than those in the 40 Hz group (0.95 (0.37, 1.06 ), P<0.05 ). (3) Nissl staining results showed that Nissl bodies in the hippocampal CA1 area of young rats in Ctr, 40 Hz and 70 Hz group were all arranged neatly and tightly, no edema was found in the surrounding stroma, and no obvious inflammatory cell infiltration was found. Conclusion:70 Hz frequency flash stimulation may promote the ability of learning memory and autonomous exploratory of young rats.

BACKGROUNDEfficient cell adhesion and proliferation is a central issue in cell-based tissue engineering, which offers great promise for repair of urethral defects or strictures. This study evaluated the adhesion and growth of rabbit uroepithelium on a surface-modified three-dimensional poly-L-lactic acid (PLLA) scaffold.

METHODSUrethral mucosa were harvested from male New Zealand rabbits and the urothelium were dissociated and then cultured. Immunocytochemistry on cultured uroepithelium for pancytokeratin and uroplakin II and TE-7 confirmed pure populations. After in vitro proliferation, cells were seeded onto a surface-modified urethral scaffold with non-knitted filaments. The morphology and viability of the cells were examined by immunohistochemical and fluorescence staining. Inverted and scanning microscopes were used to document cell growth and adhesion.

RESULTSThree to five days after primary culture, the uroepithelial cells gradually became confluent, assuming a cobblestone pattern. The filaments of the urethral scaffold had excellent biocompatibility and allowed growth of the uroepithelium, without affecting viability. The uroepithelial cells adhered to and grew well on the scaffold. After 3 - 7 days, the cells grew vigorously and meshes of the scaffold were full of uroepitheliums.

CONCLUSIONSThe surface-modified urethral scaffold with non-knitted filaments allows the growth of uroepithelium and can serve as a carrier for the tissue engineering of urethra.

Absorbable Implants ; Animals ; Cells, Cultured ; Epithelial Cells ; physiology ; Lactic Acid ; Male ; Polyesters ; Polymers ; Rabbits ; Tissue Engineering ; methods ; Urethra ; cytology

Female ; Humans ; Influenza A Virus, H1N1 Subtype ; Influenza Vaccines ; therapeutic use ; Influenza, Human ; prevention & control ; Male ; Medical Staff ; statistics & numerical data ; Refusal to Participate ; statistics & numerical data

OBJECTIVETo investigate the effect of nano-hydroxyapatite/collagen (nHA/collagen) composite as a graft extender and enhancer when combined with recombinant human bone morphogenetic protein-2 (rhBMP-2) on lumbar intertransverse fusion in rabbits.

METHODSSixty-four adult female New Zealand white rabbits, aged 1 year and weighing 3.5-4.5 kg, underwent similar posterolateral intertransverse process arthrodesis and were randomly divided into 4 groups based on different grafts: autogenous cancellous bone alone (ACB group), nHA/collagen alone (HAC group), half autogenous cancellous bone and half nHA/collagen (ACB+HAC group) and nHA/collagen combined with rhBMP-2 (HAC+BMP group). The fusion masses were analyzed by manual palpation, radiography, biomechanical testing and histological examination.

RESULTSFusion was observed in 4 cases in the 6th week and in 5 cases in the 10th week after surgery in ACB group. No case showed fusion in HAC group. In ACB+HAC group, there was fusion in 3 cases in the 6th week and in 4 cases in the 10th week after surgery. In HAC+BMP group, fusion in 1 case was found in the 4th week, in 5 cases in the 6th week and in 6 cases in the 10th week after surgery. It suggested that ACB, ACB+HAC and HAC+BMP groups showed similar fusion ratio and mechanical strength in the 6th and 10th week after surgery. According to the microstructure analysis of the samples, nHA/collagen had no negative effect when implanted together with ilium autograft. In HAC+BMP group, new bone-like tissue was observed in the 2nd week postoperatively, and nearly all of the implanted composites were replaced by mature bone matrix and new bones in 10th week postoperatively.

CONCLUSIONSThe nHA/collagen, especially combined with rhBMP-2, is a promising bone substitute, for it has quick biodegradation, fine bone-bending ability, and high osteoconductivity on posterolateral spinal fusion in rabbits.

Analysis of Variance ; Animals ; Biomechanical Phenomena ; Bone Morphogenetic Protein 2 ; Bone Morphogenetic Proteins ; pharmacology ; Disease Models, Animal ; Durapatite ; pharmacology ; Female ; Lumbar Vertebrae ; drug effects ; surgery ; Osseointegration ; drug effects ; Probability ; Rabbits ; Sensitivity and Specificity ; Spinal Fusion ; methods ; Tensile Strength ; Transforming Growth Factor beta

OBJECTIVETo elucidate the roles of monocyte chemotactic factors (MCP-1, RANTES and Fractalkine) on the vulnerability of atherosclerotic plaques in patients with stable (SAP) and unstable angina pectoris (UAP).

METHODSPatients with SAP (n = 50) and UAP (n = 50) underwent coronary angiography (CAG) and intravenous ultrasound (IVUS) were included in the study. Monocyte chemotaxis was assayed by the transwell chamber. Concentrations of hs-CRP, MCP-1, RANTES and Fractalkine were measured by Enzyme-linked-immunosorbent assay (ELISA). mRNA expression of MCP-1, RANTES and Fractalkine in the monocytes was detected by RT-PCR.

RESULTSIVUS evidenced soft lipid plaques in 48% UAP patients and in 16% SAP patients (P < 0.05). SAP patients had mainly fibrous and mixed plaques. Plaque burden and vascular remodeling index were significantly higher in UAP patients than in SAP patients (P < 0.01). The averaged number of migrated monocytes in the UAP patients were higher than that in patients with SAP (P < 0.01). Concentration of hs-CRP, MCP-1, RANTES and Fractalkine were significantly higher in UAP patients than those of SAP patients (P < 0.05 or P < 0.01). mRNA expression of MCP-1, RANTES and Fractalkine in patients with UAP was significantly higher than those of SAP patients (P < 0.05).

CONCLUSIONUpregulated monocyte chemotactic factors (MCP-1, RANTES and Fractalkine) might promote coronary plaque vulnerability in UAP patients.

Angina Pectoris ; metabolism ; pathology ; Angina, Unstable ; metabolism ; pathology ; Chemokine CCL2 ; metabolism ; Chemokine CCL5 ; metabolism ; Chemokine CX3CL1 ; metabolism ; Coronary Angiography ; Female ; Humans ; Male ; Middle Aged ; Plaque, Atherosclerotic ; pathology ; RNA, Messenger ; genetics

Objective To compare the antibody response between preterm and full-term infants after primary immunization of hepatitis B vaccine (HepB).Methods Infants who were aged 7-12 months and had completed primary immunization with 5 μg HepB made by recombinant dexyribonucleic acid techniques in saccharomyces cerevisiae (HepB-SC) or 10 μg HepB made by recombinant dexyribonucleic acid techniques in Hansenula polymorpha (HepB-HP) on 0-1-6 schedule were investigated in four provinces (municipality) including Beijing,Shandong,Jiangsu and Guangxi of China.Among them,all preterm infants were selected to form the preterm group and the 1:1 matching full-term infants with the same month-age,gender and residence were randomly selected to form the full-term group.Their HepB history was determined by immunization certificate and all of their parents were interviewed with standard questionnaire to get their birth information.Blood samples were obtained from all anticipants and were tested for Anti-HBs by chemiluminescence microparticle immuno-assay (CMIA).Results Total anticipants were 648 pairs of infants.The rates of non-response,low-response,normal-response and high-response after the primary immunization were 1.39％,8.64％,45.83％ and 44.14％ in the preterm group,respectively.The corresponding rates were 1.08％,9.26％,44.91％ and 44.75％ in the full-term group.The above four rates did not show significant differences between the two groups (P＞0.05).The geometric mean concentrations (GMC) of anti-HBs in the pre-term and full-term group were 755.14 and 799.47 mIU/ml respectively.There was no significantly difference in the GMCs between the two groups (P＞0.05).Results from multivariable conditional logistic analysis showed that preterm was not an influencing factor to the antibody response after HepB primary immunization among newborns even after debugging the other influencing factors.Conclusion The autibody response after HepB primary immunization were similar among the preterm and full-term infants.The preterm newborns could be immunized under the same HepB immunization strategy.

Objective To compare the antibody response induced by primary immunization with 5 μ g and 10 μ g hepatitis B vaccine made by recombinant DNA techniques among the newborns.Methods Healthy infants who had completed primary immunization with 5 μg hepatitis B vaccine made by recombinant dexyribonucleic acid techniques in Saccharomyces (Hep-SC) or 10 μg hepatitis B vaccine made by recombinant dexyribonucleic acid techniques in Hansenula polymorpha (HepB-HP) were included in the study.Kids under study were 7-12 months of age and had been on 0-1-6 schedule.Standardized questionnaire was used and blood samples were collected.The titer of antibody to hepatitis B surface antigen (anti-HBs) was detected by Chemiluminescence Microparticle Imunoassay (CMIA).If anti-HBs happened to be under 10 mIU/ml,HBV DNA was further detected by nested-PCR to distinguish occult hepatitis B virus infection.Sero-conversion rate and titer of anti-HBs were compared between the two kinds of hepatitis B vaccines.Multivariate analysis was used to find the relationship between the kind of hepatitis B vaccine as well as the antibody response after debugging the other influencing factors including month-age,gender,birth-weight,premature birth and mother' s HBsAg status.Results 8947 infants vaccinated with 5 μg HepB-SC and 4576 infants vaccinated with 10 μg HepB-HP were investigated.In the 5 μg group,the rates of non-,low-,normal- and high-response were 1.88％,15.18％,61.42％ and 21.52％ respectively.In the 10 μg group,the corresponding rates were 0.15％,2.16％,29.42％ and 68.26％ respectively.The non-,low-,normal-response rates were all higher in 5 μg group than in 10 μg group (P＜0.01),while the high-response rate was much higher in 10 μg group than in 5 μ g group (P＜0.01).The geometric mean concentration (GMC) of anti-HBs were 354.81 mIU/ml (95％ CI:338.84-363.08 mIU/ml) and 1778.28 mIU/ml (95％CI:1698.24-1819.70 mIU/ml) in the 5 μg group and 10 μg group respectively.The GMC was statistically higher in the 10 μg group than in the 5 μg group (P＜0.001).The seroconversion rate and GMC were significantly different between the two groups even after debugging the other influencing factors.Conclusion Better anti-HBs response could be achieved by primary immunization with 10 μg HepB-HP than with 5 μg HepB-SC among newborns.