BACKGROUND:With aging,the regenerative capacity and differentiation function of bone marrow mesenchymal stem cells progressively decline,reducing bone tissue repair efficacy.Thus,identifying bone marrow mesenchymal stem cell subpopulations with enhanced osteogenic potential is of significant importance for advancing bone tissue engineering.OBJECTIVE:To evaluate the osteogenic differentiation potential differences between STRO-1 positive and negative bone marrow mesenchymal stem cells under osteogenic induction conditions.METHODS:SD rat bone marrow mesenchymal stem cells were isolated and cultured.The expression of CD29,CD45,CD90,and STRO-1 was identified via flow cytometry and immunofluorescence.Immunomagnetic cell sorting was used to separate STRO-1 positive and negative bone marrow mesenchymal stem cells.The cells of two groups were subjected to osteogenic induction for 7 and 14 days.qRT-PCR and western blotting were performed to analyze differences in osteogenesis-related gene expression(Collagen I,Runt-related transcription factor 2,osteoprotegerin,and osteocalcin)and protein levels.Alizarin red staining and alkaline phosphatase staining were used to observe calcium nodule formation.RESULTS AND CONCLUSION:Flow cytometry showed high expression levels of CD29 and CD90 and low expression of CD45,with a positive STRO-1 expression rate of 12.8％.Immunofluorescence results were consistent with those of flow cytometry.After magnetic cell sorting,STRO-1 positive cells demonstrated a higher colony formation rate than STRO-1 negative cells.On day 14,STRO-1 positive cells showed significantly higher osteogenic differentiation potential than on day 7,with significantly elevated osteogenesis-related marker levels compared to STRO-1 negative cells(P＜0.01).The findings indicate that STRO-1 positive bone marrow mesenchymal stem cells exhibit significant advantages in osteogenic potential,providing a theoretical basis for their selection as ideal seed cells in bone tissue engineering.In future applications,they may represent a promising therapeutic approach for bone defect repair.

BACKGROUND:With aging,the regenerative capacity and differentiation function of bone marrow mesenchymal stem cells progressively decline,reducing bone tissue repair efficacy.Thus,identifying bone marrow mesenchymal stem cell subpopulations with enhanced osteogenic potential is of significant importance for advancing bone tissue engineering.OBJECTIVE:To evaluate the osteogenic differentiation potential differences between STRO-1 positive and negative bone marrow mesenchymal stem cells under osteogenic induction conditions.METHODS:SD rat bone marrow mesenchymal stem cells were isolated and cultured.The expression of CD29,CD45,CD90,and STRO-1 was identified via flow cytometry and immunofluorescence.Immunomagnetic cell sorting was used to separate STRO-1 positive and negative bone marrow mesenchymal stem cells.The cells of two groups were subjected to osteogenic induction for 7 and 14 days.qRT-PCR and western blotting were performed to analyze differences in osteogenesis-related gene expression(Collagen I,Runt-related transcription factor 2,osteoprotegerin,and osteocalcin)and protein levels.Alizarin red staining and alkaline phosphatase staining were used to observe calcium nodule formation.RESULTS AND CONCLUSION:Flow cytometry showed high expression levels of CD29 and CD90 and low expression of CD45,with a positive STRO-1 expression rate of 12.8％.Immunofluorescence results were consistent with those of flow cytometry.After magnetic cell sorting,STRO-1 positive cells demonstrated a higher colony formation rate than STRO-1 negative cells.On day 14,STRO-1 positive cells showed significantly higher osteogenic differentiation potential than on day 7,with significantly elevated osteogenesis-related marker levels compared to STRO-1 negative cells(P＜0.01).The findings indicate that STRO-1 positive bone marrow mesenchymal stem cells exhibit significant advantages in osteogenic potential,providing a theoretical basis for their selection as ideal seed cells in bone tissue engineering.In future applications,they may represent a promising therapeutic approach for bone defect repair.

Objective: To compare the clinical outcomes and biomechanical characteristics of 1-, 2-, and 3-level pedicle subtraction osteotomy (PSO), and establish selection criteria based on preoperative radiographic parameters. Methods: Patients undergone PSO to treat ankylosing spondylitis from February 2009 to May 2019 in Sun Yat-sen Memorial Hospital of Sun Yat-sen University were enrolled. According to the quantity of osteotomy performed, the participants were divided into group A (1-level PSO, n = 24), group B (2-level PSO, n = 19), and group C (3-level PSO, n = 11). Clinical outcomes were assessed before surgery and at the final follow-up. Comparisons of the radiographic parameters and quality-of-life indicators were performed among and within these groups, and the selection criteria were established by regression. Finite element analysis was conducted to compare the biomechanical characteristics of the spine treated with different quantity of osteotomies under different working conditions. Results: Three-level PSO improved the sagittal parameters more significantly, but resulted in longer operative time and greater blood loss (p < 0.05). Greater stress was found in the proximal screws and proximal junction area of the vertebra in the model simulating 1-level PSO. Larger stress of screws and vertebra was observed at the distal end in the model simulating 3-level PSO. Conclusion Multilevel PSO works better for larger deformity correction than single-level PSO by allowing greater sagittal parameter correction and obtaining a better distribution of stress in the hardware construct, although with longer operation time and greater blood loss. Three-level osteotomy is recommended for the patients with preoperative of global kyphosis > 85.95°, T1 pelvic angle > 62.3°, sagittal vertical alignment > 299.55 mm, and pelvic tilt+ chin-brow vertical angle > 109.6°.

Objective: To compare the clinical outcomes and biomechanical characteristics of 1-, 2-, and 3-level pedicle subtraction osteotomy (PSO), and establish selection criteria based on preoperative radiographic parameters. Methods: Patients undergone PSO to treat ankylosing spondylitis from February 2009 to May 2019 in Sun Yat-sen Memorial Hospital of Sun Yat-sen University were enrolled. According to the quantity of osteotomy performed, the participants were divided into group A (1-level PSO, n = 24), group B (2-level PSO, n = 19), and group C (3-level PSO, n = 11). Clinical outcomes were assessed before surgery and at the final follow-up. Comparisons of the radiographic parameters and quality-of-life indicators were performed among and within these groups, and the selection criteria were established by regression. Finite element analysis was conducted to compare the biomechanical characteristics of the spine treated with different quantity of osteotomies under different working conditions. Results: Three-level PSO improved the sagittal parameters more significantly, but resulted in longer operative time and greater blood loss (p < 0.05). Greater stress was found in the proximal screws and proximal junction area of the vertebra in the model simulating 1-level PSO. Larger stress of screws and vertebra was observed at the distal end in the model simulating 3-level PSO. Conclusion Multilevel PSO works better for larger deformity correction than single-level PSO by allowing greater sagittal parameter correction and obtaining a better distribution of stress in the hardware construct, although with longer operation time and greater blood loss. Three-level osteotomy is recommended for the patients with preoperative of global kyphosis > 85.95°, T1 pelvic angle > 62.3°, sagittal vertical alignment > 299.55 mm, and pelvic tilt+ chin-brow vertical angle > 109.6°.

Objective: To compare the clinical outcomes and biomechanical characteristics of 1-, 2-, and 3-level pedicle subtraction osteotomy (PSO), and establish selection criteria based on preoperative radiographic parameters. Methods: Patients undergone PSO to treat ankylosing spondylitis from February 2009 to May 2019 in Sun Yat-sen Memorial Hospital of Sun Yat-sen University were enrolled. According to the quantity of osteotomy performed, the participants were divided into group A (1-level PSO, n = 24), group B (2-level PSO, n = 19), and group C (3-level PSO, n = 11). Clinical outcomes were assessed before surgery and at the final follow-up. Comparisons of the radiographic parameters and quality-of-life indicators were performed among and within these groups, and the selection criteria were established by regression. Finite element analysis was conducted to compare the biomechanical characteristics of the spine treated with different quantity of osteotomies under different working conditions. Results: Three-level PSO improved the sagittal parameters more significantly, but resulted in longer operative time and greater blood loss (p < 0.05). Greater stress was found in the proximal screws and proximal junction area of the vertebra in the model simulating 1-level PSO. Larger stress of screws and vertebra was observed at the distal end in the model simulating 3-level PSO. Conclusion Multilevel PSO works better for larger deformity correction than single-level PSO by allowing greater sagittal parameter correction and obtaining a better distribution of stress in the hardware construct, although with longer operation time and greater blood loss. Three-level osteotomy is recommended for the patients with preoperative of global kyphosis > 85.95°, T1 pelvic angle > 62.3°, sagittal vertical alignment > 299.55 mm, and pelvic tilt+ chin-brow vertical angle > 109.6°.

Objective: To compare the clinical outcomes and biomechanical characteristics of 1-, 2-, and 3-level pedicle subtraction osteotomy (PSO), and establish selection criteria based on preoperative radiographic parameters. Methods: Patients undergone PSO to treat ankylosing spondylitis from February 2009 to May 2019 in Sun Yat-sen Memorial Hospital of Sun Yat-sen University were enrolled. According to the quantity of osteotomy performed, the participants were divided into group A (1-level PSO, n = 24), group B (2-level PSO, n = 19), and group C (3-level PSO, n = 11). Clinical outcomes were assessed before surgery and at the final follow-up. Comparisons of the radiographic parameters and quality-of-life indicators were performed among and within these groups, and the selection criteria were established by regression. Finite element analysis was conducted to compare the biomechanical characteristics of the spine treated with different quantity of osteotomies under different working conditions. Results: Three-level PSO improved the sagittal parameters more significantly, but resulted in longer operative time and greater blood loss (p < 0.05). Greater stress was found in the proximal screws and proximal junction area of the vertebra in the model simulating 1-level PSO. Larger stress of screws and vertebra was observed at the distal end in the model simulating 3-level PSO. Conclusion Multilevel PSO works better for larger deformity correction than single-level PSO by allowing greater sagittal parameter correction and obtaining a better distribution of stress in the hardware construct, although with longer operation time and greater blood loss. Three-level osteotomy is recommended for the patients with preoperative of global kyphosis > 85.95°, T1 pelvic angle > 62.3°, sagittal vertical alignment > 299.55 mm, and pelvic tilt+ chin-brow vertical angle > 109.6°.

Objective: To compare the clinical outcomes and biomechanical characteristics of 1-, 2-, and 3-level pedicle subtraction osteotomy (PSO), and establish selection criteria based on preoperative radiographic parameters. Methods: Patients undergone PSO to treat ankylosing spondylitis from February 2009 to May 2019 in Sun Yat-sen Memorial Hospital of Sun Yat-sen University were enrolled. According to the quantity of osteotomy performed, the participants were divided into group A (1-level PSO, n = 24), group B (2-level PSO, n = 19), and group C (3-level PSO, n = 11). Clinical outcomes were assessed before surgery and at the final follow-up. Comparisons of the radiographic parameters and quality-of-life indicators were performed among and within these groups, and the selection criteria were established by regression. Finite element analysis was conducted to compare the biomechanical characteristics of the spine treated with different quantity of osteotomies under different working conditions. Results: Three-level PSO improved the sagittal parameters more significantly, but resulted in longer operative time and greater blood loss (p < 0.05). Greater stress was found in the proximal screws and proximal junction area of the vertebra in the model simulating 1-level PSO. Larger stress of screws and vertebra was observed at the distal end in the model simulating 3-level PSO. Conclusion Multilevel PSO works better for larger deformity correction than single-level PSO by allowing greater sagittal parameter correction and obtaining a better distribution of stress in the hardware construct, although with longer operation time and greater blood loss. Three-level osteotomy is recommended for the patients with preoperative of global kyphosis > 85.95°, T1 pelvic angle > 62.3°, sagittal vertical alignment > 299.55 mm, and pelvic tilt+ chin-brow vertical angle > 109.6°.

Objective To investigate the beneficial role of synbiotics in the intestinal microbiota of patients with chronic functional constipation (CFC).Methods According to the inclusion and exclusion criteria,6 patients with CFC were enrolled with their fresh fecal samples collected,after a continuous treatment of one month their fresh fecal samples collected again.Meanwhile,6 healthy volunteers were enrolled as the control group with their fresh fecal samples collected.All samples were transported with ice and stored in -80 ℃ refrigerator,and were analyzed by metagenomics sequencing.Results After 4 weeks of symbiotic treatment,the intestinal microbiota had changed in species in patients with CFC.Bacteria of Escherichia_ coli,Clostridium_ sp._ SS2/1 and Clostridium_ sp._ 7_ 3_ 54FAA,which were rich in the people with constipation,decreased in abundance after the treatment.Bacteria of Lactobacillus_ oris and Bifidobacterium _ animalis,which were rich in the healthy people,increased in content after the treatment.Bacteria of Veillonella_ parvula,Veillonella_ sp._ 6_ 1_ 27,Veillonella_ sp._ 3 _ 1_ 44 which were rich in the healthy people,decreased in content after the treatment.LEfSe analysis showed that Parabacteroides distaso nis,Escherichia_ coli and Enterobacter-cloacae were the specific species of the three groups respectively.Conclusion Synbiotics can change the intestinal microbiota showing therapeutic effect,thus can be used as a novel clinical treatment method.

BACKGROUND:Bone morphogenetic protein-2 (BMP-2) is a key to bone formation and repair.However,it has some disadvantages such as easy to lose and degrade and difficult to sustain continuous effect.OBJECTIVE:To study the preparation and properties of silk fibroin/chitosan/nano-hydroxyapatite (SF/CS/nHA) scaffold loading BMP-2.METHODS:After silk degumming,dissolution and purification,2％ SF solution was obtained.BMP-2 was dissolved in 2％ CS solution,and then fully mixed with equal volume of SF solution and proper amount of nHA.At last,the SF/CS/nHA scaffold loading BMP-2 was prepared using freeze-drying method as experimental group.The SF/CS/nHA scaffold was soaked in the BMP-2 solution as control group.The scaffold porosity was measured by Archimedes method,the surface morphology of the scaffold was observed by scanning electron microscope,the compressive strength was measured by universal testing machine.Scaffolds in the two groups were soaked in PBS,and the release of BMP-2 was measured by ELISA method at different time points.RESULTS AND CONCLUSION:(1) The scaffolds in the two groups had irregular porous structure,interconnected pores and uneven pore wall.There was no significant difference between the two groups in mean pore diameter,porosity and maximum compressive strength.(2) On the 1st day,the release rate of BMP-2 was 4.63％ in the experimental group,and the release curve increased slowly.After 28 days,the release curve of BMP-2 was transferred to the plateau stage.But in the control group,the release rate of BMP-2 on the 1stday was 58.84％,and it was a significant initial burst release.The release curve increased rapidly,and was transferred to the platform stage on the 10th day.The release rate of BMP-2 release was significantly different between the two groups at days 1,2,4,10 (P ＜ 0.05).These results show that the SF/CS/nHA scaffold loading BMP-2 could sustainably and slowly release BMP-2.

OBJECTIVE:To provide reference for evaluating the new round of essential medicine bidding and purchase policy in China,ensuring the stability of essential medicine supply and improving national essential medicine system.METHODS:Based on the theoretical analysis,taking Shanghai and Yunan province as sample,the questionnaire was designed to investigate the difficulty to implement essential drug purchase policy in essential medicine supply system,and the bidding situation evaluation of production enterprises by both sides of local drug bidding among staff in production enterprises,circulation enterprises,primary health care institutions and other institutions.The types of influential factors for the implementation of essential medicine purchase policy were determined finally.Factor analysis method was used to screen the key influential factors.RESULTS & CONCLUSIONS:Four common factors had a great influence on the implementation of essential medicine policy in China.The impact of the large to small is the rationality of the tender procurement program,the standardization of pharmaceutical production,the stability of demand for drug use and macroeconomic policy regulation and protection.It is suggested to further improve the drug recruitment system,select the products that have quality assurance and production specifications,and fully meet the diverse needs of the market,while provide relatively stable usage information for manufacturers.If necessary,"drug purchase with target quantity" of Shanghai model can be forced to carry out by policy so as to ensure that the interests of all parties in the pharmaceutical supply chain are treated fairly.