Objective To explore the relationship between minimal residual disease(MRD)on the 19th day(D19)and prognosis of children with acute B-lymphoblastic leukemia(B-ALL),as well as the correlation with related biological changes.Methods A total of 88 children with B-ALL newly diagnosed in this hospital from April 2016 to April 2020 who met the enrollment conditions were analyzed for induction therapy D19 MRD,overall survival(OS)rate,event-free survival(EFS)rate,chromosome karyotype,fusion gene and mu-tation gene.MRD≥ 0.01％was considered positive,and they were divided into MRD positive group and MRD negative group.The characteristics of OS rate,EFS rate,immunophenotype and molecular biology/cytogenet-ics were compared between the two groups over a period of 3 years.Results The 3-year OS rate and EFS rate of 88 pediatric patients were 92.0％and 86.4％,respectively.The rates of OS rate and EFS rate in MRD posi-tive group were lower than those in MRD negative group,with statistical significance(P＜0.05).The detec-tion rate of CD10 in MRD positive group was lower than that in MRD negative group,and the difference was statistically significant(P＜0.05).Thirty-two patients(36.4％)detected 8 types of 35 fusion genes.The de-tection rates of BCR-ABL1 and E2A-PBX1 in MRD positive group were higher than those in MRD negative group,and the differences were statistically significant(P＜0.05).Among 48 cases(54.5％)of pediatric pa-tients,41 types of 91 mutated genes were detected,and the remaining mutated genes were less than 5 cases.Abnormal karyotype was detected in 18 cases(20.5％),and no mitotic phase was detected in 17 cases.There was no difference in MRD between normal and abnormal karyotype.Binary Logistic regression analysis showed that BCR-ABL1 and E2A-PBX1 were prognostic factors of children with B-ALL.Conclusion The positive D19 MRD is the influential factor of adverse OS and EFS in children with B-ALL.Both E2A-PBX1 and BCR-ABL1 have adverse effects on the prognosis of children with B-ALL.

BACKGROUND: In recent years, the development of tissue engineering has provided a new approach for the treatment of periodontal bone defect. Tissue engineering therapy includes seed cells, scaffolds and growth factors. Platelet gel contains a large number of platelet growth factors, and collagen is often used for the preparation of scaffold materials. Therefore, the platelet gel and collagen biologically active composite membrane can provide scaffolds and growth factors for the defect bone. OBJECTIVE: To investigate the effect of autologous platelet gel-collagen biologically active composite membrane on the repair of periodontal bone defect in rats. METHODS: Forty-two Wistar rats (Shanghai Xipuer-Bikai Experimental Animal Co., Ltd., China) were selected. (1) Collagen was cut into 5 mm×2 mm size, and 10 mL of whole blood was extracted from 6 rats to obtain platelet-rich plasma. Autologous platelet gel-collagen composite membrane was prepared by adding bovine thrombin, calcium chloride and collagen in a certain proportion. Platelets in whole blood and in platelet-rich plasma were detected. The levels of platelet derived growth factor AB, transforming growth factor-β, basic fibroblast growth factor and vascular endothelial growth factor in whole blood and platelet-rich plasma were detected by ELISA. (2) The models of mandibular periosteal defect were established in 36 rats (the size of the bone defect was 5 mm×2 mm, and the root surface cementum was removed) , and randomly divided into two groups. Autologous platelet gel-collagen group placed the autologous platelet gel-collagen composite membrane in the bone defect, and the control group did not place any materials. The hematoxylin-eosin staining of periodontal tissues of rats in each group was analyzed at 2, 4 and 8 weeks after surgery. Rate of new born, new centumum formation, new alveolar bone formation, and new periodontal ligament tissue formation height were measured. The expression of bone morphogenetic protein-2 was detected by immunohistochemical staining. RESULTS AND CONCLUSION: (1) The mean platelet count in platelet-rich plasma was 4.78 times as high as the whole blood, indicating that the number of platelets increased significantly after prepared into platelet-rich plasma (P < 0.05) . The levels of platelet derived growth factor AB, transforming growth factor-β, basic fibroblast growth factor and vascular endothelial growth factor in platelet-rich plasma were 3.10, 3.45, 7.17 and 5.45 times of the whole blood, respectively (P < 0.05) . (2) The results of hematoxylin-eosin staining observed that the rate of new born, new centumum formation, new alveolar bone formation, and new periodontal ligament tissue formation height at 2 weeks in the autologous platelet gel-collagen group showed no significant difference from the control group (P> 0.05) . At 4 and 8 weeks, all above indexes in the autologous platelet gel-collagen group were significantly higher than those in the control group (P < 0.05) . (3) Results of immunohistochemical staining revealed that at 2 weeks, bone morphogenetic protein-2 in the autologous platelet gel-collagen group began to express, and the expression of bone morphogenetic protein-2 was highest at 4 weeks (P < 0.05) , and the positive expression was weakened at 8 weeks (P> 0.05) . (4) Our results clarify that autologous platelet gel-collagen bioactive composite membrane can significantly promote the regeneration of new tooth, which is associated with the expression of bone morphogenetic protein-2, and reduce the repair time after periodontal tissue defect.