[Objective]To explore the expression of OPG/OPGL protein and its significance in rat model of trauma-induced osteonecrosis of the femoral head(ONFH). [Methods]Thirty-two SD rats about 6 months were divided randomly into experimental and control groups.The animal model of femoral head necrosis was established in 32 SD rats by removing round ligaments of femoral head.Animals were sacrificed at 1,2,4 and 6 weeks after operation,respectively.The specimens were examined through histological observation under light microscope.The other side with sham operation served as normal control group.The comparison of fat tissue with hematopoietic tissue in the cavity of bone marrow of femoral head were performed by CMIAS computer-assisted image and statistical analysis.The percentage of empty lacuna in the femoral heads was obtained.Immunohistochemistry was used to determine the expression of OPG/OPGL protein in ONFH.[Results]ONFH was confirmed in experimental group.The model in various stages was successfully duplicated.Compared with normal control group,the percentage of empty lacuna remarkable increase was found in experimental groups in different periods(P

Objective To compare the value of automatic breast volume scanner (ABVS) with enhanced magnetic resonance imaging(MRI) in the diagnosis of breast masses.Methods Seventy-four patients with 80 breast masses underwent preoperative ultrasound examinations including ABVS and MRI.The values of ABVS and MRI in the diagnosis of breast masses were comparatively analyzed.Results Among the 80 breast masses that were surgically removed,37 masses were benign and 43 masses were malignant.The sensitivity,specificity,accuracy,positive predictive value and negative predictive value of ABVSin the diagnosis of breast malignant masses were 94.6％,79.1％,86.3％,79.5％ and 94.4％,respectively,those of MRI were 94.6 ％,86.0 ％,90.0 ％,85.4 ％ and 94.9 ％,respectively,and those of the combination of ABVS and MRI were 94.6％,93.0％,93.8％,92.1％,and 95.2％,respectively.The sensitivity and specificity were not significant difference between ABVS and MRI in the diagnosis of breast malignant masses(P ＞0.05).The specificity of the combination ABVS and MRI in the diagnosis of breast malignant masses were significantly higher than that of ABVS (x2 =4.17,P =0.04).The sensitivity,specificity and accuracy of convergence sign in the diagnosis of breast malignant masses were 64.9 ％,97.7 ％ and 82.5 ％,respectively.Conclusions ABVS and MRI are both valuable in the diagnosis of breast masses,and the combination of ABVS and MRI is the most valuable due to high specificity.

BACKGROUND:Previous studies have shown that home-made porous tantalum has non-toxicity and good biocompatibility, and can promote osteogenesis. Herein, we explore the mechanisms of tantalum-bone interface osseointegration.OBJECTIVE:To observe the morphological characteristics and expressions of integrin β1 and fibronectin on the interface between porous tantalum and bone tissues after implantation into the right rabbit femur, and to evaluate the biological mechanisms of tantalum-bone interface osseointegration.METHODS: Animal models of bilateral femoral condyle defects were made in Japanese big ear rabbits. Porous tantalum rod and allogeneic bone were respectively implanted into the left (experimental group) and right (control group) femur of rabbits. The animal specimens at the bone defect region were taken and made into paraffin sections and hard tissue sections at postoperative 2, 4, 8 weeks for morphological observation of new bone at the junction between the tantalum rod and host bone under light microscope, for osteogenic observation of the tantalum-bone interface under scanning electron microscope, and for immunohistochemical detection of integrin β1 and fibronectin expression.RESULTS AND CONCLUSION:Porous tantalum was bonded closely with the host bone. The loose and thick fibrous capsule was observed in the early stage and became thinner in the late stage shown by hematoxylin-eosin staining. The new bone was visible on tantalum-bone interface. Hard tissue slicing observation showed that the new bone was seen on the porous tantalum-bone interface, blood capillaries grew into the pores at postoperative 2 weeks and the pores were full of new bone tissues at postoperative 4 and 8 weeks. Under the scanning electron microscope, the osteoblasts appeared on the tantalum surface and in the pores at the early stage, and bone maturation and lamelar bone were seen at the late stage. The immunohistochemical results showed that the expression of integrin β1 in the experimental group was significantly lower than that in the control group at postoperative 2 weeks (P < 0.05), but the expression of fibronectin had no significant difference between the two groups (P > 0.05). In addition, there was a decline trend in the expression of integrin β1 and fibronectin atpostoperative 2, 4, 8 weeks. To conclude, the porous tantalum material is beneficial to enhance adhesion of osteoblasts on the surface and inside the micro-pores. Increased expression of integrin β1 and fibronectin on the tantalum-bone interface at early stage may promote early osteogenesis, while their decreased expression at bone maturing stage can promote osseointegration and bone remodeling.

BACKGROUND: At present, there is evidence that domestic porous tantalum has good biocompatibility and osteogenic properties, but the specific osteogenic mechanism and its effect on osteogenic factors are still unclear. OBJECTIVE: To observe the effects of domestic porous tantalum materials on the expression of collagen type I, tissue transglutaminase-2 and calcium-binding protein A4 in MG63 cells. METHODS: MG63 cells in logarithmic growth phase were inoculated onto 24-well plates and cultured in three groups: in blank group, conventional medium was added; in tantalum extract group, porous tantalum material extract was added; and in tantalum scaffold group, porous tantalum material and conventional medium were added. On 1, 3, 5, 7 and 9 days of culture, the cell proliferation of each group was detected by cell counting kit-8 method. On 5 days of culture, the levels of collagen type I, tissue transglutaminase-2 and calcium-binding protein A4 secreted by MG63 cells in each group were detected by ELISA. Western blot assay was used to detect the expression of three proteins in each group. RESULTS AND CONCLUSION: (1) With the prolongation of culture time, the number of cells in each group increased gradually. There was no difference in cell proliferation among the three groups at different time points (P> 0.05). (2) The secretory levels of collagen type I and tissue transglutaminase-2 in the tantalum scaffold group were significantly higher than those in the blank group and tantalum extract group (P < 0.05), while the secretion of collagen type I and tissue transglutaminase-2 in the tantalum extract group was significantly higher than that in the blank group (P < 0.05). The secretion of calcium-binding protein A4 in the tantalum scaffold group was significantly lower than that in the other two groups (P < 0.05). (3) The expression of collagen type I and tissue transglutaminase-2 protein in the tantalum scaffold group was significantly higher than that in the blank group and tantalum extract group (P < 0.05), while the expression of collagen type I and tissue transglutaminase-2 protein in the tantalum extract group was significantly higher than that in the blank group (P < 0.05). The expression of calcium-binding protein A4 in the tantalum scaffold group was significantly lower than that in the blank group and tantalum extract group (P < 0.05). To conclude, domestic porous tantalum materials could promote the secretion of collagen type I and tissue transglutaminase-2 by MG63 cells, and inhibit the secretion of calcium-binding protein A4.

BACKGROUND: A number of clinical trials addressing olfactory ensheathing cells for the treatment of chronic spinal cord injury have been conducted in the world, but the efficacy and safety are still controversial. OBJECTIVE: To evaluate the safety and efficacy of olfactory ensheathing cell transplantation for chronic spinal cord injury, and to further compare its short-and long-term efficacy. METHODS: PubMed, Cochrane Library, EMBASE, CNKI and WanFang databases were searched at July 23, 2018 for retrieval of clinical trials addressing olfactory ensheathing cells in the treatment of chronic spinal cord injury. Types and cases of adverse events during the safety trial should be recorded in detail. In the enrolled studies, American Spinal Injury Association scale was used to assess the motor, light touch, and pinprick scores of spinal cord injury patients before and after cell transplantation. The follow-up time was recorded. Systematic evaluation of efficacy data was performed using Review Manager 5.3. RESULTS AND CONCLUSION: Both short-and long-term follow-up data showed that the neurological function of patients was significantly improved after olfactory ensheathing cell transplantation (P < 0.05) , and the results were homogeneous (I2 < 50％ and P> 0.1). However, the long-term efficacy was not as good as the short-term efficacy, which may be related to chronic rejection and olfactory ensheathing cell survival. The overall adverse event rate was 8.99％, and no complications associated with olfactory ensheathing cells occurred. These findings show that olfactory ensheathing cell transplantation is effective and safe in the treatment of chronic spinal cord injury, but it is still necessary to explore more minimally invasive approaches to reduce surgical complications. In addition, a large number of high-quality experiments and clinical trials are warranted to confirm factors affecting the long-term efficacy of olfactory ensheathing cell transplantation.

Objective:To explore the changes in topological attributes of structural covariance network based on cortical thickness and the brain functional activities in patients with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis by graph theory and functional connectivity (FC) analyses, and to investigate whether these changes were correlated to cognitive impairment.Methods:A total of 33 patients with anti-NMDAR encephalitis from Department of Neurology of the First Affiliated Hospital of Guangxi Medical University(patient group) and 35 healthy controls(control group) with matched gender, age, and education were included from July 2018 to November 2021.All subjects received cognitive function assessments, structural and functional magnetic resonance imaging scans.Structural covariance networks were constructed in the two groups based on cortical thickness values and topological characteristics of networks were computed.A non-parametric permutation test which repeated 1 000 times was used to compare the characteristics of the networks between the two groups.Brain regions with abnormal topology were defined as region of interest(ROI), and FC values in global brain level were calculated.SPM 12 and RESTplus were used to identify the brain regions with significant differences in FC values between the two groups.Finally, Spearman correlation analysis between FC values of significant brain regions and cognitive scores were performed by SPSS 24.0.Results:The cognitive score of patients with anti-NMDAR encephalitis (27.0(23.5, 28.0)) was lower than that in control group(29.0(27.0, 30.0)) ( Z=-3.029, P=0.002). Graph theory analysis found that the patients showed significantly increased clustering coefficients ( P=0.004) and decreased global efficiency ( P=0.004) compared with healthy controls.Moreover, the nodal efficiency of left ventral posterior cingulate cortex (vPCC) and right dorsal posterior cingulate cortex (dPCC), as well as the nodal degree centrality of left vPCC and left polar planum of superior temporal gyrus (ppSTG) in patient group were significantly decreased ( P<0.05, FDR corrected) compared with control group.FC analysis showed the increased FC values between left vPCC and posterior cerebellum (MNI: x=6, y=-66, z=-21), as well as between left ppSTG and anterior cerebellum (MNI: x=6, y=-54, z=-12) (GRF corrected, voxel level P<0.001, cluster level P<0.05) in patient grooup.The FC values between left vPCC and posterior cerebellum were negatively correlated with the cognitive scores ( r=-0.403, P=0.020). Conclusion:Patients with anti-NMDAR encephalitis show abnormal topology of structural covariance network based on cortical thickness and altered FC values, some of which are correlated to cognition and may be the underlying neural mechanism of cognitive impairment in patients with anti-NMDAR encephalitis.

Threonine aldolases catalyze the aldol condensation of aldehydes with glycine to furnish β-hydroxy-α-amino acid with two stereogenic centers in a single reaction. This is one of the most promising green methods for the synthesis of optically pure β-hydroxy-α-amino acid with high atomic economy and less negative environmental impact. Several threonine aldolases from different origins have been identified and characterized. The insufficient -carbon stereoselectivity and the challenges of balancing kinetic versus thermodynamic control to achieve the optimal optical purity and yield hampered the application of threonine aldolases. This review summarizes the recent advances in discovery, catalytic mechanism, high-throughput screening, molecular engineering and applications of threonine aldolases, with the aim to provide some insights for further research in this field.
Amino Acids ; Catalysis ; Glycine ; Glycine Hydroxymethyltransferase/metabolism* ; Kinetics ; Substrate Specificity ; Threonine

Food enzymology and enzyme engineering is an important professional course of food science. The course includes the basic theory of enzymology, enzyme engineering technology and the application of enzymes in food industry. Considering the knowledge gap between the teaching contents and the cutting-edge researches, the team constantly adjusted and optimized the course contents to enable students to keep up with state-of-the-art progress by carefully mining the cutting-edge researches. Taking cutting-edge researches as the breakthrough point, we explored the problem-based learning (PBL) teaching model under the guidance of outcome-based education (OBE) concept, and highlighted the importance of the teacher-student and student-student interactions to improve students' enthusiasm and participation. A diversified assessment system was established to evaluate the performance of students in the learning process. The teaching reform consolidated the basic knowledge and expanded the academic frontiers, and fostered students' ability in analyzing problems, designing solutions and achieving team communication. The course may give new insights into the teaching reform of food enzymology and enzyme engineering and other related courses.
Humans ; Students ; Learning

Production of chiral amines and unnatural amino-acid using ω-transaminase can be achieved by kinetic resolution and asymmetric synthesis, thus ω-transaminase is of great importance in the synthesis of pharmaceutical intermediates. By genomic data mining, a putative ω-transaminase gene hbp was found in Burkholderia phytofirmans PsJN. The gene was cloned and over-expressed in Escherichia coli BL21 (DE3). The recombinant enzyme (HBP) was purified by Ni-NTA column and its catalytic properties and substrate profile were studied. HBP showed high relative activity (33.80 U/mg) and enantioselectivity toward β-phenylalanine (β-Phe). The optimal reaction temperature and pH were 40 ℃ and 8.0-8.5, respectively. We also established a simpler and more effective method to detect the deamination reaction of β-Phe by UV absorption method using microplate reader, and demonstrated the thermodynamic property of this reaction. The substrate profiling showed that HBP was specific to β-Phe and its derivatives as the amino donor. HBP catalyzed the resolution of rac-β-Phe and its derivatives, the products (R)-amino acids were obtained with about 50% conversions and 99% ee.
Bacterial Proteins ; biosynthesis ; genetics ; Burkholderia ; enzymology ; Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Transaminases ; biosynthesis ; genetics