[Objective]To investigate the capability of synthesis BMP-2-derived peptide on osteogenic induction in bone marrow stem cells(BMSEs),and to evaluate the osteoinductivity of BMP-2-derived peptide in vitro.[Method]After segregating and cultivating four weeks Wistar rats marrow stromal cells in induction group were induced by osteogenasis medium containing 200 gg/ml BMP-2-derived peptide,and in non-inductional group BMSCs were still culture with DMEM medium.Following continue culture for 2~4 weeks,cells film preparation,alkaline phosphatase activity and calcium deposition were measured.Type I collagen(CoM)and osteopontin(OPN)mRNA expression were measured using real-time fluorescent quantitative polymerase chain reaction(FQ-PCR)technique.The capability of synthesis BMP-2-derived peptide on osteogenic induction of BMSCs was investigated.[Result]After inductived with BMP-2-derived peptide.BMSCs cultured survived well greatly changed in cell morphology,and showed a biological and morphologie characteristics similar to those of osteoblasts.The lever of alkaline phosphatase activity and calcium deposition increased.Col-Ⅰand OPN mRNA were expressed at higher level.In non-inductional group no conspicuous osteogenic induction was shown.[Conclusion]BMP-2-derived peptide can induce BMSCs to differentiate into osteoblasts.It has the similar capacity of osteogenic induction as nature BMP-2,so BMP-2-derived peptide is an ideal cell agent for bone tissue engineering,and can be available widely.

To experimentally evaluate the ectopic osteogenetic capacity of synthesized BMP2-derived peptide P24 combined with poly lactic-co-glycolic acid (PLGA), Wistar rats were divided into two groups: group A, in which BMP2-derived peptide P24/PLGA complex was implanted, and group B which received simple PLGA implant. The complex was respectively implanted into the back muscles of rats. Samples were taken the 1st, 4th, 8th, and the 12th week after the implantation. Their bone formation was detected by X-ray examination, and tissue response was histologically observed. Western blotting was used for the detection of the expression of collagen I (Col-I) and osteopontin (OPN). There was acute inflammation in the tissue around both types of implants at early stage. The cartilage was found around implant areas 4 weeks after the implantation of BMP2-derived peptide p24/PLGA complex, 8 weeks after the implantation, osteoblasts were found, and 12 weeks after the implantation, typical trabecular bone structure was observed. In group B, after 12 weeks, no osteoblasts were found. It is concluded that PLGA is an ideal scaffold material for bone tissue engineering. BMP2-derived peptide can start endochondral ossification and is more effective in inducing ectopic osteogenesis.

In this study, the bioactivity of a novel BMP2-derived oligopeptide P24 was investigated by using the model of rabbit femoral defect after loaded in the biodegradable poly (lactic acid / glycolic acid / asparagic acid-co-polyethylene glycol) (PLGA-[ASP-PEG]). A 1.5-cm unilateral segmental bone defect was created in the left femoral diaphysis in each of the 30 new zealand white rabbits. The defects of 18 legs filled with BMP2-derived peptide P24 combined with PLGA-[ASP-PEG] scaffold serves as the experimental group, and the defects in the rest 12 rabbits filled with (PLGA-[ASP-PEG]) without P24 as control group. The bone-repairing capability in the target region of the two group was grossly, radiologically, histopathologically and biomechanically evaluated 4, 8 and 12 weeks after the operation. Our results showed that in each group, primary healing of incision was achieved in the two groups. Radiographically, in experimental group, defects were filled with induced callus within 8 weeks, and a cortical bone-like structure was observed in some animals at the 12th week. According to the standardized stage of bone defect repair, 9 (64.28%) achieved grade-4 healing. In contrast, little bone formation was seen in the defects even 12 weeks after the operation, and 5 (62.50%) had grade 0 healing in this group. Histologically, tissue engineering material was mostly absorbed and cartilage was found around implants in the experimental group at the 4th week; 8 weeks after operation, the engineering material was completely absorbed, and formation of woven bone was observed and typical trabecular bone structure could be seen. In control group, 8 weeks after operation, the defect was filled with fibrous tissues, and no bone-like structure was observed. Statistical analysis showed very significant difference in biomechanical indicators between the two groups (P<0.05). It is concluded that new oligopeptide P24 can induce excellent bone regeneration and promote bone repair.

To experimentally evaluate the ectopic osteogenetic capacity of synthesized BMP2-derived peptide P24 combined with poly lactic-co-glycolic acid (PLGA), Wistar rats were divided into two groups: group A, in which BMP2-derived peptide P24/PLGA complex was implanted,and group B which received simple PLGA implant. The complex was respectively implanted into the back muscles of rats. Samples were taken the 1 st, 4 th, 8 th, and the 12 th week after the implantation.Their bone formation was detected by X-ray examination, and tissue response was histologically observed. Western blotting was used for the detection of the expression of collagen Ⅰ (Col- Ⅰ ) and osteopontin (OPN). There was acute inflammation in the tissue around both types of implants at early stage. The cartilage was found around implant areas 4 weeks after the implantation of BMP2-derived peptide p24/PLGA complex, 8 weeks after the implantation, osteoblasts were found, and 12 weeks after the implantation, typical trabecular bone structure was observed. In group B, after 12 weeks, no osteoblasts were found. It is concluded that PLGA is an ideal scaffold material for bone tissue engineering. BMP2-derived peptide can start endochondral ossification and is more effective in inducing ectopic osteogenesis.

In this study, the bioactivity of a novel BMP2-derived oligopeptide P24 was investigated by using the model of rabbit femoral defect after loaded in the biodegradable poly (lactic acid / glycolic acid / asparagic acid-co-polyethylene glycol) (PLGA-[ASP-PEG]). A 1.5-cm unilateral segmental bone defect was created in the left femoral diaphysis in each of the 30 new zealand white rabbits.The defects of 18 legs filled with BMP2-derived peptide P24 combined with PLGA-[ASP-PEG]scaffold serves as the experimental group, and the defects in the rest 12 rabbits filled with(PLGA-[ASP-PEG]) without P24 as control group. The bone-repairing capability in the target region of the two group was grossly, radiologically, histopathologically and biomechanically evaluated 4, 8and 12 weeks after the operation. Our results showed that in each group, primary healing of incision was achieved in the two groups. Radiographically, in experimental group, defects were filled with induced callus within 8 weeks, and a cortical bone-like structure was observed in some animals at the12th week. According to the standardized stage of bone defect repair, 9 (64.28%) achieved grade-4healing. In contrast, little bone formation was seen in the defects even 12 weeks after the operation,and 5 (62.50%) had grade 0 healing in this group. Histologically, tissue engineering material was mostly absorbed and cartilage was found around implants in the experimental group at the 4th week;8 weeks after operation, the engineering material was completely absorbed, and formation of woven bone was observed and typical trabecular bone structure could be seen. In control group, 8 weeks after operation, the defect was filled with fibrous tissues, and no bone-like structure was observed. Statistical analysis showed very significant difference in biomechanical indicators between the two groups (P＜0.05). It is concluded that new oligopeptide P24 can induce excellent bone regeneration and promote bone repair.

Objective To summarize the clinical features of neuroblastoma (NB)with N - myc gene amplifi-cation in order to analyze tumor shrinkage and bone marrow remission in the early stage of chemotherapy,and to eva-luate the children's initial sensitivity to chemotherapy. Methods The medical records of 38 patients with N - myc am-plification of NB were reviewed (bone marrow or tumor tissues were positive during fluorescence in situ hybridization probe),who were treated between February 2012 to December 2016 at the Hematology Oncology Center,Beijing Chil-dren's Hospital,Capital Medical University. The regimens included chemotherapy,surgery,stem cell transplantation, radiotherapy,and maintenance treatment. The data were reviewed for the medical history. The variations of biomarker, bone marrow cells and the primary site were analyzed before and after 2 courses of CAV (Cyclophosphamide + Adriamy-cin + Vincristine)regimen chemotherapy,in order to observe the short - term effect of chemotherapy and the results were described with statistics. Results Total 38 cases were studied,22 boys(58. 9％)and 16 girls(42. 1％). The median age was 30 months. The primary sites of 37 cases of tumor were located in the retroperitoneal and adrenal area,1 case located in the posterior mediastinum. Bone marrow cytology was negative in 12 cases of them,but bone marrow biopsy suggested bone marrow metastasis,while bone marrow cytomorpholigic examinations were positive in the other 26 cases. Of all the 37 cases the lactate dehydrogenase (LDH)levels were reported higher than the normal value. LDH level was under 500 U/ L in one case,9 cases above 4000 U/ L. The neuron specific enolase (NSE)level of all the cases was higher than the normal and NSE level in 36 cases was higher than 100 μg/ L. In one patient the diameter of tumor was less than 5 cm,lager than 10 cm in 32 cases. The lesion of 33 tumor cases before chemotherapy by enhanced CT was ≤100 cm3 in 12 cases,> 100 - 500 cm3 in 11 cases,among which 6 cases ranged from 500 - 1000 cm3 ,4 cases larger than 1000 cm3 . All the 38 cases received 2 courses of chemotherapy. LDH levels of 4 cases became normal,and LDH levels fell under 500 U/ L in 18 cases,while LDH levels of the other 3 cases were above 1000 U/ L. Among 38 cases, the NSE level in 6 cases was reduced to normal,and 16 cases reduced to 25 - 100 μg/ L. The bone marrow examination of 36 cases reversed to negative. According to the image examination,the overall response rate after 2 courses of chemo-therapy was 84. 8％ . One case achieved very good partial remission,21 cases achieved partial response,7 cases a-chieved metastatic remission,2 cases had no remission,while 2 cases showed progression. After 2 courses of chemother-apy,the tumor diameter in 7 cases was less than 5 cm,while that of 22 cases was above 10 cm. Conclusions The ma-jority primary site of NB with N - myc gene amplification is located in retroperitoneal and adrenal area. Patients with the huge tumor have a heavy burden and the biomarker is always high at the early stage. NB with N - myc gene amplifica-tion is sensitive to chemotherapy. After 2 courses of chemotherapy,there is a sharp decrease in the level of biomarker and the tumor burden. Chemotherapy can diminish the burden of tumor in early stage. But because of the huge burden and the huge size of tumor,it's not the best time for surgery and stem cell collection. The patients should go on receiving chemotherapy for remission of disease.

Objective:To explore the clinical significance of the MYCN gene, PHOX2B gene and plasma cell-free DNA (cfDNA) in risk stratification and predicting the prognosis of high-risk neuroblastoma (NB). Methods:This was a prospective study involving 94 high-risk NB children admitted to Beijing Children′s Hospital, Capital Medical University from August 2017 to December 2018.Relative levels of MYCN and PHOX2B and cfDNA at diagnosis, and 4 and 6 cycles of chemotherapy were detected, and their differences were compared by the Chi- square test.Kaplan-Meier survival analysis was performed to explore their prognostic potential in high-risk NB. Results:Among the 94 high-risk NB children, 14 cases (14.9%) had MYCN amplification, 76 cases (80.8%) had positive expression of PHOX2B and 56 cases (59.6%) had cfDNA level higher than 100 μg/L.The proportion of high lactate dehydrogenase (LDH, ≥1 500 U/L) level in the MYCN gene amplification group (6/14 cases) was higher than that in the normal group (9/80 cases) ( P=0.009). The proportion of multi-site metastasis (54/76 cases) and high neuron specific enolase (NSE) level (NSE≥370 μg/L, 37/76 cases) in PHOX2B positive group were significantly higher than those in the negative group (5/14 cases, 2/14 cases) ( P=0.015, 0.020). The proportion of high LDH and high NSE in high cfDNA concentration (≥229.6 μg/L)group (13/37 cases, 28/37 cases) were significantly higher than those in low cfDNA concentration group (2/48 cases, 10/48 cases) (all P<0.001). With the decreased tumor burden during the treatment, the copy number of PHOX2B gene and cfDNA level were significantly lower than those at the initial diagnosis [0 (0-719.6) copies vs.1 723.5 (0-186 000.0) copies; 19.0 (1.1-225.5) μg/L vs.200.6 (8.0-5 247.4) μg/L, all P<0.001]. The 2-year event-free survival (EFS) rate of the MYCN gene amplification group was significantly lower than that of the normal group[(33.3±13.1)% vs.(58.5±7.1)%, P=0.020]. The 2-year EFS rate of PHOX2B positive group was significantly lower than that of the negative group[(47.9±7.1)% vs.(79.1±11.1)%, P=0.043]. EFS rate in high cfDNA concentration group was significantly lower than that in cfDNA low concentration group[(38.6±9.8)% vs.( 71.7±8.2)%, P=0.001]. After 6 cycles of chemotherapy, EFS rate in the PHOX2B positive group was significantly lower than that in the negative group [(16.7±14.4)% vs.( 60.6±6.6)%, P=0.014]; which was significantly lower in the Metaiodobenzylguanidine (MIBG) positive group than that of the negative group[(35.2±11.7)% vs.(65.8±7.1)%, P=0.037]. The MYCN gene and cfDNA concentration were not correlated with the prognosis of high-risk NB.Survival analysis of the combination of PHOX2B and MYCN gene ( PHOX2B+ /MIBG + , PHOX2B+ or MIBG + , PHOX2B-/MIBG -) showed a significant difference in the survival among three groups[0 vs.(53.6±1.2)% vs.(65.5±7.4)%, P=0.003]. Conclusions:The MYCN and PHOX2B gene and cfDNA concentration are of significance in risk stratification and predicting the prognosis of high-risk NB.Compared with the MYCN gene and cfDNA concentration, the PHOX2B gene is more suitable for monitoring the curative effect of chemotherapy on high-risk NB.A combined analysis of PHOX2B gene and MIBG before treatment can be more accurate in evaluating the treatment effect and residual lesions.