Objective To compare target dosimetric distribution and normal tissue radiation between different static intensity-modulated radiation therapy (IMRT)plans and volumetric modulated arc therapy (VMAT),and to identify the best IMRT plan for lymphoma patients needed mediastinal radiation. Methods A total of 11 patients with lymphoma who received first course radiotherapy in the mediastinal region after che-motherapy in Cancer Hospital & Shenzhen Hospital,Chinese Academy of Medical Sciences and Peking Union Medical College from March 2017 to January 2019 were included in the study. There were 8 males and 3 fe-males,2 patients were in Ann Arbor stage Ⅰ-Ⅱ,and 9 cases in Ⅲ-Ⅳ stage. There were 6 patients with Hodgkin lymphoma (HL)and 5 patients with non-Hodgkin lymphoma (NHL). Patients with HL and NHL were given prescript doses of 36 Gy and 50 Gy,respectively. Three plans were designed for each patient:static 5F-IMRT,7F-IMRT and VMAT plan. The target dosimetric distribution,normal tissue radiation dose,and effi-ciency of each plan were evaluated. Results The mean conformity index (CI)and homogeneity index (HI) values of plan target volume (PTV)in 5F-IMRT,7F-IMRT,VMAT plan were 0. 64 ± 0. 06,0. 67 ± 0. 05, 0. 76 ± 0. 04 (F = 17. 045,P < 0. 001)and 1. 07 ± 0. 01,1. 07 ± 0. 01,1. 09 ± 0. 01 (F = 9. 258,P =0. 001),respectively. VMAT showed significantly better CI than two static IMRT plans (both P < 0. 001),but worse HI (both P < 0. 001). The lungs low dose irradiation volume (V (V 5 )and high dose irradiation volume 30 )in 5F-IMRT,7F-IMRT,VMAT plan were (43. 98 ± 7. 77)％,(42. 71 ± 4. 98)％,(55. 92 ± 8. 16)％(F = 8. 281,P = 0. 001)and (8. 19 ± 2. 97)％,(8. 25 ± 2. 87)％,(7. 53 ± 3. 16)％ (F = 0. 140,P =0. 870),respectively. The volume of low dose irradiation in lungs of VMAT plan was significantly higher than 5F-IMRT and 7F-IMRT plans (both P < 0. 001),while high dose volume was no significant difference. The left and right breast low dose irradiation volume (V 4 )in 5F-IMRT,7F-IMRT and VMAT plan were (24. 29 ± 8. 14)％,(23. 87 ± 7. 70)％,(80. 17 ± 22. 92)％ (F = 14. 505,P = 0. 005)and (22. 12 ± 13. 28)％, (21. 13 ± 13. 01)％,(81. 77 ± 20. 76)％ (F = 13. 938,P = 0. 006),respectively. VMAT showed signifi-cantly higher breast low dose irradiation volume than static IMRT plan (both P < 0. 05). The number of monitor units and treatment time in 5F-IMRT,7F-IMRT,VMAT plan were (1622 ± 281)MU,(1729 ± 286)MU, (411 ± 75)MU (F = 105. 277,P < 0. 001)and (6. 79 ± 0. 93)min,(7. 42 ± 0. 95)min,(4. 98 ± 0. 00)min (F = 29. 545,P < 0. 001),respectively. VMAT showed significantly less monitor units than static IMRT (both P < 0. 001)and shorter treatment time (both P < 0. 001). Conclusion For lymphoma patients who have the indication of mediastinal radiotherapy,VMAT is highly efficient and has no definite dose advan-tage,the static 5F-IMRT or 7F-IMRT plan has good conformal and uniform target area,and some organs at risk exposure is even lower.

OBJECTIVETo evaluate the effect of co-culture system of bone marrow mesenchymal stem cells (BMSC) and vascular endothelial cells (EC) on osteogenesis.

METHODSBMSC were isolated by whole bone marrow centrifugal adherent method. Then BMSC were induced into EC with induced medium. Co-culture system in different proportions of BMSC and EC (10:0, 10:1, 8:2, 7:3, 5:5, 3:7, 2:8, 1:10, 0:10) were further evaluated. The cell growth level of BMSC was examined. The CD44 expression of BMSC and von willebrand factor (vWF) expression of vascular EC were examined by immunofluorescence. Furthermore, calcium nodules exhibited by alizarin red staining, alkaline phosphatase activity, and the expression of osteogenic genes by reverse transcription-quantitative PCR (RT-qPCR) were observed to validate the osteogenesis of co-culture system.

RESULTSThe growth curve of P3 passage of BMSC demonstrated the doubling time of BMSC was 39.9 h. The positive specific markers of BMSC and EC showed efficient induction. Although the calcium nodules ratio of the co-culture [group 7:3 (19.0 ± 3.0) and group 5:5 (20.8 ± 2.9)] was not significantly different (P > 0.05), but higher than that of other co-culture groups with a significant difference (P < 0.01). Alkaline phosphatase activity was increased with prolonged induction of osteogenic medium. While alkaline phosphatase activity of group 10:0 (16.84 ± 0.82), group 10:1 (15.86 ± 3.10), group 8:2 (16.37 ± 1.33), group 7:3 (17.99 ± 1.98), and group 5:5 (17.49 ± 0.87) did not show significant difference after osteogenic induction for 7 days (P > 0.05), but significantly higher than that of other co-culture groups (P < 0.05). The co-culture ratio of 7:3 (33.74 ± 0.99) was slightly higher than that of 5:5 (31.09 ± 0.87), but significantly higher than that of other groups (P < 0.01). Moreover, the osteocalcin (OCN) and runt-related transcription factor 2 (RUNX2) expression of group 7:3 was significantly higher than that of other groups.

CONCLUSIONSThe EC that derived from BMSC can promote the BMSC differentiate into osteoblasts. The co-culture system of BMSC and EC with the ratio of 7:3 increases the alkaline phosphatase activity and facilitates the expression of osteogenic genes.

Alkaline Phosphatase ; metabolism ; Bone Marrow Cells ; cytology ; physiology ; Cell Culture Techniques ; Cell Differentiation ; Cell Proliferation ; Coculture Techniques ; Core Binding Factor Alpha 1 Subunit ; metabolism ; Endothelial Cells ; cytology ; physiology ; Humans ; Hyaluronan Receptors ; metabolism ; Mesenchymal Stromal Cells ; cytology ; physiology ; Osteoblasts ; cytology ; Osteocalcin ; metabolism ; Osteogenesis ; physiology ; Time Factors ; von Willebrand Factor ; metabolism